Display apparatus and electronic equipment

Abstract

Provided is a novel display apparatus that has excellent convenience, usefulness, or reliability. The present invention is a display apparatus that includes a first light-emitting device and a second light-emitting device, the second light-emitting device being adjacent to the first light-emitting device. The first light-emitting device comprises a first unit that emits light, a second unit that emits light, a first intermediate layer, and a first layer. The first intermediate layer is sandwiched between the second unit and the first unit; the first layer is sandwiched between the first intermediate layer and the first unit; and unpaired electrons can be observed in the first layer with a spin density of 1 × 1016 to 1 × 1018 spins / cm3 or less. The second light-emitting device comprises a third unit that emits light, a fourth unit that emits light, a second intermediate layer, and a second layer. The second intermediate layer is sandwiched between the fourth unit and the third unit; the second layer is sandwiched between the second intermediate layer and the third unit; there is a gap between the second intermediate layer and the first intermediate layer; and there is a gap between the second layer and the first layer.

Description

Display devices, electronic equipment

[0001] One embodiment of the present invention relates to a display device, an electronic device, or a semiconductor device.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, a driving method thereof, or a manufacturing method thereof.

[0003] A method for manufacturing an organic EL display that can form an emissive layer without using a fine metal mask is known, including the steps of depositing a first luminescent organic material containing a mixture of a host material and a dopant material above an electrode array including first and second pixel electrodes formed above an insulating substrate to form a first luminescent layer as a continuous film extending across a display area including the electrode array, irradiating a portion of the first luminescent layer located above the second pixel electrodes with ultraviolet light without irradiating a portion of the first luminescent layer located above the first pixel electrodes with ultraviolet light, depositing a second luminescent organic material containing a mixture of a host material and a dopant material different from the first luminescent organic material on the first luminescent layer to form a second luminescent layer as a continuous film extending across the display area, and forming a counter electrode above the second luminescent layer (see Patent Document 1).

[0004] JP 2012-160473 A

[0005] An object of one embodiment of the present invention is to provide a novel display device with excellent convenience, usefulness, or reliability, or a novel electronic device with excellent convenience, usefulness, or reliability, or a novel display device, a novel electronic device, or a novel semiconductor device.

[0006] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these will become apparent from the description of the specification, drawings, claims, etc., and it is possible to extract other problems from the description of the specification, drawings, claims, etc.

[0007] (1) One embodiment of the present invention is a display device including a first light-emitting device and a second light-emitting device, wherein the second light-emitting device is adjacent to the first light-emitting device.

[0008] The first light-emitting device comprises a first electrode, a second electrode, a first unit, a second unit, a first intermediate layer, and a first layer, wherein the first unit is sandwiched between the second electrode and the first electrode, the second unit is sandwiched between the second electrode and the first unit, the first intermediate layer is sandwiched between the second unit and the first unit, and the first layer is sandwiched between the first intermediate layer and the first unit.

[0009] The first unit has a function of emitting a first light, and the second unit has a function of emitting a second light.

[0010] The first intermediate layer has a function of supplying holes to the second unit, and the second intermediate layer has a function of supplying electrons to the first layer.

[0011] The first layer contains unpaired electrons, and the unpaired electrons are measured by an electron spin resonance (ESR) apparatus to determine a concentration of 1×10 １６ spins / cm ３ 1x10 or more １８ spins / cm ３ The spin density can be observed as follows: The first layer includes a first inorganic compound and a first organic compound, the first organic compound has an unshared electron pair, and the first organic compound interacts with the first inorganic compound to form a half-occupied orbital.

[0012] The second light-emitting device comprises a third electrode, a fourth electrode, a third unit, a fourth unit, a second intermediate layer, and a second layer, wherein the third unit is sandwiched between the fourth electrode and the third electrode, the fourth unit is sandwiched between the fourth electrode and the third unit, the second intermediate layer is sandwiched between the fourth unit and the third unit, and the second layer is sandwiched between the second intermediate layer and the third unit.

[0013] The third unit has a function of emitting a third light, and the fourth unit has a function of emitting a fourth light.

[0014] The second intermediate layer has a function of supplying holes to the fourth unit, and the second intermediate layer has a function of supplying electrons to the second layer.

[0015] The second intermediate layer has a first gap between it and the first intermediate layer, and the second layer has a second gap between it and the first layer, and the second layer includes a first inorganic compound and a first organic compound.

[0016] (2) Another embodiment of the present invention is a display device in which the first light-emitting device includes a third layer, and the third layer is sandwiched between the first unit and the first electrode.

[0017] The second light-emitting device also includes a fourth layer, the fourth layer being sandwiched between the third unit and the third electrode, and the fourth layer having a third gap between it and the third layer.

[0018] (3) In addition, in one aspect of the present invention, the third layer is 1×10 ２ [Ω・cm] or more 1×10 ８ The display device has an electrical resistivity of [Ω·cm] or less.

[0019] This makes it possible to suppress current flowing between the first intermediate layer and the second intermediate layer. It also makes it possible to suppress current flowing between the third layer and the fourth layer. It also makes it possible to suppress the occurrence of crosstalk between the first light-emitting device and the second light-emitting device. As a result, it is possible to provide a novel display device that is excellent in convenience, usefulness, and reliability.

[0020] (4) Another aspect of the present invention is a display device, in which the unpaired electron has a g value in the range of 2.003 to 2.004.

[0021] (5) Another embodiment of the present invention is a display device in which the unpaired electrons can be observed in the atmosphere after 24 hours with an electron spin resonance (ESR) apparatus at a spin density of 50% or more of the initial spin density.

[0022] This allows for a wider range of processing options to be selected after the first layer is formed. Furthermore, after the first intermediate layer is formed on the first layer, the first intermediate layer and the first layer can be processed into a predetermined shape, for example, by photolithography. Furthermore, after the second unit is formed, the second unit and the first layer can be processed into a predetermined shape, for example, by photolithography. Furthermore, for example, the second light-emitting device can be formed adjacent to the first light-emitting device, separate from it, without using a fine metal mask. As a result, a novel display device with excellent convenience, usefulness, and reliability can be provided.

[0023] (6) Another embodiment of the present invention is a display device in which the first organic compound has an electron-deficient heteroaromatic ring.

[0024] (7) Another embodiment of the present invention is a display device in which the first organic compound has a lowest unoccupied molecular orbital (LUMO) level in the range of −3.6 eV to −2.3 eV.

[0025] (8) Another embodiment of the present invention is a display device in which the first inorganic compound contains a metal element and oxygen.

[0026] (9) Another embodiment of the present invention is a display device in which the first inorganic compound contains lithium and oxygen.

[0027] This makes it possible to reduce the driving voltage of the light-emitting device and the power consumption, thereby providing a novel display device that is highly convenient, useful, and reliable.

[0028] (10) Another embodiment of the present invention is a display device in which the first intermediate layer has unpaired electrons.

[0029] (11) Another embodiment of the present invention is a display device in which the first intermediate layer contains the second organic compound and the third organic compound.

[0030] The second organic compound has at least one of an electron-rich heteroaromatic ring or an aromatic amine, and the second organic compound has a highest occupied molecular orbital (HOMO) level in the range of −5.7 eV to −5.3 eV.

[0031] The third organic compound has fluorine, a lowest unoccupied molecular orbital (LUMO) level of −5.0 eV or less, and an electron accepting property with respect to the second organic compound.

[0032] (12) Another embodiment of the present invention is a display device in which the third organic compound has a cyano group.

[0033] (13) Another embodiment of the present invention is a display device in which the first intermediate layer does not contain a metal element.

[0034] This allows the first intermediate layer to be formed without using a material that requires high temperatures for film formation, such as a metal oxide. Furthermore, the temperature required for film formation of the first intermediate layer can be suppressed. Furthermore, since the first intermediate layer can be easily formed, productivity can be improved. As a result, a novel display device that is excellent in convenience, usefulness, and reliability can be provided.

[0035] (14) Another embodiment of the present invention is a display device in which the first intermediate layer includes a fifth layer and a sixth layer.

[0036] The fifth layer is sandwiched between the first layer and the sixth layer and includes a fourth organic compound having a lowest unoccupied molecular orbital (LUMO) level in the range of −4.0 eV to −3.3 eV.

[0037] This makes it possible to reduce the driving voltage and power consumption, thereby providing a novel display device that is highly convenient, useful, and reliable.

[0038] (15) Another embodiment of the present invention is the display device described above, including a first functional layer, a second functional layer, and a display region.

[0039] The first functional layer includes a driving circuit, and the driving circuit generates a first image signal and a second image signal.

[0040] The second functional layer overlaps the first functional layer, and the second functional layer includes a first pixel circuit and a second pixel circuit, where the first pixel circuit is supplied with a first image signal and the second pixel circuit is supplied with a second image signal.

[0041] The display area comprises a set of pixels, the set of pixels including a first pixel and a second pixel, the first pixel comprising a first light-emitting device and a first pixel circuit, the first light-emitting device being electrically connected to the first pixel circuit, and the second pixel comprising a second light-emitting device and a second pixel circuit, the second light-emitting device being electrically connected to the second pixel circuit.

[0042] (16) Another embodiment of the present invention is an electronic device including a computing unit and the above-described display device.

[0043] The calculation unit generates image information, and the display device displays the image information.

[0044] (17) Another embodiment of the present invention is an electronic device including an arithmetic unit and the above-described display device.

[0045] The first functional layer includes a computing unit, which generates image information, and a display device which displays the image information.

[0046] In the drawings accompanying this specification, components are classified by function and shown as block diagrams that are independent of each other, but in reality, it is difficult to completely separate components by function, and one component may be involved in multiple functions.

[0047] In this specification, the names of the source and drain of a transistor are interchangeable depending on the polarity of the transistor and the level of the potential applied to each terminal. Generally, in an n-channel transistor, a terminal to which a low potential is applied is called a source, and a terminal to which a high potential is applied is called a drain. In a p-channel transistor, a terminal to which a low potential is applied is called a drain, and a terminal to which a high potential is applied is called a source. In this specification, for convenience, the connection relationship of a transistor may be described assuming that the source and drain are fixed, but in reality, the names of the source and drain are interchangeable depending on the above-mentioned potential relationship.

[0048] In this specification, the source of a transistor refers to a source region that is part of a semiconductor film that functions as an active layer, or a source electrode connected to the semiconductor film. Similarly, the drain of a transistor refers to a drain region that is part of the semiconductor film, or a drain electrode connected to the semiconductor film. Furthermore, the gate refers to a gate electrode.

[0049] In this specification, a state in which transistors are connected in series means, for example, a state in which only one of the source or drain of a first transistor is connected to only one of the source or drain of a second transistor, and a state in which transistors are connected in parallel means a state in which one of the source or drain of a first transistor is connected to one of the source or drain of a second transistor, and the other of the source or drain of the first transistor is connected to the other of the source or drain of the second transistor.

[0050] In this specification, "connection" means an electrical connection, and corresponds to a state in which a current, voltage, or potential can be supplied or transmitted. Therefore, a connected state does not necessarily refer to a direct connection, but also includes a state in which a current, voltage, or potential can be supplied or transmitted via a circuit element such as a wiring, resistor, diode, or transistor.

[0051] In this specification, even when components that appear independent on a circuit diagram are connected to each other, in reality, one conductive film may have the functions of multiple components, for example, when part of a wiring functions as an electrode. In this specification, the term "connection" also includes such cases where one conductive film has the functions of multiple components.

[0052] In this specification, one of a first electrode and a second electrode of a transistor refers to a source electrode, and the other refers to a drain electrode.

[0053] According to one embodiment of the present invention, a novel display device with excellent convenience, usefulness, or reliability can be provided. Alternatively, a novel electronic device with excellent convenience, usefulness, or reliability can be provided. Alternatively, a novel display device, a novel electronic device, or a novel semiconductor device can be provided.

[0054] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these will become apparent from the description in the specification, drawings, claims, etc., and it is possible to extract other effects from the description in the specification, drawings, claims, etc.

[0055] FIG. 1 is a diagram illustrating a configuration of a display device according to an embodiment. FIGS. 2A and 2B are diagrams illustrating a configuration of a display panel according to an embodiment. FIG. 3 is a circuit diagram illustrating a pixel of a display panel according to an embodiment. FIGS. 4A and 4B are diagrams illustrating a configuration of a display panel according to an embodiment. FIGS. 5A to 5C are diagrams illustrating a configuration of a display panel according to an embodiment. FIG. 6 is a diagram illustrating a configuration of a display panel according to an embodiment. FIG. 7 is a diagram illustrating a configuration of a display device according to an embodiment. FIG. 8 is a diagram illustrating a configuration of a display device according to an embodiment. FIG. 9 is a diagram illustrating a configuration of a display device according to an embodiment. FIGS. 10A and 10B are diagrams illustrating a configuration of a display device according to an embodiment. FIG. 11 is a diagram illustrating a configuration of a display device according to an embodiment. FIGS. 12A and 12B are diagrams illustrating a configuration of a display device according to an embodiment. FIG. 13 is a diagram illustrating a configuration of a display device according to an embodiment. FIG. 14 is a diagram illustrating a configuration of a display device according to an embodiment. FIG. 15 is a diagram illustrating a configuration of a display device according to an embodiment. FIG. 16 is a diagram illustrating a configuration of a display device according to an embodiment. FIG. 17 is a diagram illustrating a configuration of a display device according to an embodiment. FIGS. 18A to 18C are diagrams illustrating configurations of transistors according to an embodiment. FIGS. 19A to 19C are diagrams illustrating a metal oxide according to an embodiment. FIGS. 20A to 20D are diagrams illustrating an electronic device according to an embodiment. FIGS. 21A and 21B are diagrams illustrating an electronic device according to an embodiment. FIG. 22 is a diagram illustrating a configuration of a light-emitting device according to an example. FIG. 23 is a diagram illustrating a configuration of a light-emitting device according to an example. FIG. 24 is a diagram illustrating a configuration of a light-emitting device according to an example. FIG. 25 is a diagram illustrating current density-luminance characteristics of a light-emitting device according to an example. FIG. 26 is a diagram illustrating luminance-current efficiency characteristics of a light-emitting device according to an example. FIG. 27 is a diagram illustrating voltage-luminance characteristics of a light-emitting device according to an example. FIG. 28 is a diagram illustrating voltage-current characteristics of a light-emitting device according to an example. FIG. 29 is a diagram illustrating an emission spectrum of a light-emitting device according to an example.FIG. 30 is a diagram illustrating the configuration of a light-emitting device according to an example. FIG. 31 is a diagram illustrating the configuration of a light-emitting device according to an example. FIG. 32 is a diagram illustrating the current density-luminance characteristics of a light-emitting device according to an example. FIG. 33 is a diagram illustrating the luminance-current efficiency characteristics of a light-emitting device according to an example. FIG. 34 is a diagram illustrating the voltage-luminance characteristics of a light-emitting device according to an example. FIG. 35 is a diagram illustrating the voltage-current characteristics of a light-emitting device according to an example. FIG. 36 is a diagram illustrating an emission spectrum of a light-emitting device according to an example. FIG. 37 is a diagram illustrating the configuration of a measurement sample according to an example. FIG. 38 is an electron spin resonance spectrum of a measurement sample according to an example. FIG. 39 is an electron spin resonance spectrum of a comparison sample according to an example. FIG. 40 is a diagram illustrating changes in the electron spin resonance spectrum of a measurement sample according to an example. FIG. 41 is an electron spin resonance spectrum of a measurement sample according to an example. FIG. 42 is an electron spin resonance spectrum of a measurement sample according to an example. FIG. 43 is an electron spin resonance spectrum of a measurement sample according to an example. FIG. 44 is a diagram illustrating the spin density of a measurement sample according to an example.

[0056] A display device according to one embodiment of the present invention includes a first light-emitting device and a second light-emitting device adjacent to the first light-emitting device. The first light-emitting device includes a first electrode, a second electrode, a first unit, a second unit, a first intermediate layer, and a first layer, the second electrode overlapping the first electrode, the first unit being sandwiched between the second electrode and the first electrode, the second unit being sandwiched between the second electrode and the first unit, the first intermediate layer being sandwiched between the second unit and the first unit, and the first layer being sandwiched between the first intermediate layer and the first unit. The first unit has a function of emitting first light, the second unit has a function of emitting second light, the first intermediate layer has a function of supplying holes to the second unit, and the first intermediate layer has a function of supplying electrons to the first layer. The first layer contains unpaired electrons, and the unpaired electrons are measured by electron spin resonance (ESR) to determine the unpaired electrons are 1×10 １６ spins / cm ３ 1x10 or more １８ spins / cm３ The following spin density can be observed, and the first layer includes a first inorganic compound and a first organic compound, the first organic compound having an unshared electron pair, and the first organic compound interacts with the first inorganic compound to form a half-occupied orbital.

[0057] The second light-emitting device comprises a third electrode, a fourth electrode, a third unit, a fourth unit, a second intermediate layer, and a second layer, wherein the fourth electrode overlaps the third electrode, the third unit is sandwiched between the fourth electrode and the third electrode, the fourth unit is sandwiched between the fourth electrode and the third unit, the second intermediate layer is sandwiched between the fourth unit and the third unit, the second layer is sandwiched between the second intermediate layer and the third unit, the third unit has a function of emitting third light, the fourth unit has a function of emitting fourth light, the second intermediate layer has a function of supplying holes to the fourth unit, and the second intermediate layer has a function of supplying electrons to the second layer. The second intermediate layer has a first gap between it and the first intermediate layer, and the second layer has a second gap between it and the first layer, and the second layer includes a first inorganic compound and a first organic compound.

[0058] This can suppress the current flowing between the first intermediate layer and the second intermediate layer, and can also suppress the occurrence of crosstalk between the first light-emitting device and the second light-emitting device, thereby providing a novel display device that is highly convenient, useful, and reliable.

[0059] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be readily understood by those skilled in the art that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below. In the configuration of the invention described below, the same parts or parts having similar functions will be denoted by the same reference numerals in different drawings, and repeated explanations will be omitted.

[0060] Embodiment 1 In this embodiment, a structure of a light-emitting device 550X(i,j) of one embodiment of the present invention will be described with reference to FIGS.

[0061] FIG. 1 is a cross-sectional view illustrating a structure of a light-emitting device according to one embodiment of the present invention.

[0062] <Configuration example 1 of light-emitting device 550X(i,j)> The light-emitting device 550X(i,j) has an electrode 551X(i,j), an electrode 552X(i,j), a unit 103X(i,j), a unit 103X2(i,j), and an intermediate layer 106X(i,j).

[0063] Electrode 552X(i,j) overlaps with electrode 551X(i,j). Furthermore, unit 103X(i,j) is sandwiched between electrode 552X(i,j) and electrode 551X(i,j), unit 103X2(i,j) is sandwiched between electrode 552X(i,j) and unit 103X(i,j), and intermediate layer 106X(i,j) has a region sandwiched between unit 103X2(i,j) and unit 103X(i,j).

[0064] The unit 103X(i, j) has a function of emitting light ELX, and the unit 103X2(i, j) has a function of emitting light ELX2.

[0065] In other words, the light-emitting device 550X(i,j) has multiple stacked units between the electrode 551X(i,j) and the electrode 552X(i,j). The number of stacked units is not limited to two, and three or more units can be stacked. A configuration including multiple stacked units sandwiched between the electrode 551X(i,j) and the electrode 552X(i,j) and an intermediate layer 106X(i,j) sandwiched between the multiple units is sometimes referred to as a stacked light-emitting device or a tandem light-emitting device. This allows for high-luminance light emission while maintaining low current density. Alternatively, reliability can be improved. Alternatively, driving voltage can be reduced compared to devices with the same luminance. Alternatively, power consumption can be reduced.

[0066] <<Configuration Example of Unit 103X(i,j)>> The unit 103X(i,j) has a single-layer structure or a laminated structure. For example, the unit 103X(i,j) has a layer 111X(i,j), a layer 112X(i,j), and a layer 113X(i,j) (see FIG. 1 ). The unit 103X(i,j) has a function of emitting light ELX.

[0067] Layer 111X(i,j) has an area sandwiched between layer 112X(i,j) and layer 113X(i,j), layer 112X(i,j) has an area sandwiched between electrode 551X(i,j) and layer 111X(i,j), and layer 113X(i,j) has an area sandwiched between electrode 552X(i,j) and layer 111X(i,j).

[0068] For example, the unit 103X(i,j) can be formed of a layer selected from functional layers such as a light-emitting layer, a hole-transporting layer, an electron-transporting layer, a carrier-blocking layer, etc. Also, the unit 103X(i,j) can be formed of a layer selected from functional layers such as a hole-injecting layer, an electron-injecting layer, an exciton-blocking layer, and a charge-generating layer, etc.

[0069] <<Structure Example of Layer 112X(i,j)>> For example, a material having a hole-transporting property can be used for the layer 112X(i,j). The layer 112X(i,j) can also be referred to as a hole-transporting layer. Note that a structure in which a material having a larger band gap than that of the light-emitting material contained in the layer 111X(i,j) is used for the layer 112X(i,j) is preferable. This can suppress energy transfer from excitons generated in the layer 111X(i,j) to the layer 112X(i,j).

[0070] [Material having hole transport properties] A material having a hole mobility of 1×10 −６ cm ２ A material having a hole transporting property can be suitably used as a material having a hole transporting property.

[0071] For example, an amine compound or an organic compound having a π-electron-rich heteroaromatic ring skeleton can be used as a material having hole transport properties. Specifically, a compound having an aromatic amine skeleton, a compound having a carbazole skeleton, a compound having a thiophene skeleton, a compound having a furan skeleton, or the like can be used. In particular, a compound having an aromatic amine skeleton or a compound having a carbazole skeleton is preferable because it has good reliability, high hole transport properties, and contributes to reducing driving voltage.

[0072] Examples of compounds having an aromatic amine skeleton include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), and 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP). , 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBiBP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), and the like can be used.

[0073] Examples of compounds having a carbazole skeleton that can be used include 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4′-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), and 3,3′-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP).

[0074] Examples of compounds having a thiophene skeleton that can be used include 4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV).

[0075] Examples of compounds having a furan skeleton that can be used include 4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), and the like.

[0076] <<Structure Example of Layer 113X(i,j)>> For example, a material having an electron-transporting property, a material having an anthracene skeleton, a mixed material, or the like can be used for the layer 113X(i,j). The layer 113X(i,j) can be referred to as an electron-transporting layer. Note that a structure in which a material having a larger band gap than that of the light-emitting material contained in the layer 111X(i,j) is used for the layer 113X(i,j) is preferable. This can suppress energy transfer from excitons generated in the layer 111X(i,j) to the layer 113X(i,j).

[0077] [Electron-Transporting Material] For example, a metal complex or an organic compound having a π-electron-deficient heteroaromatic ring skeleton can be used as the electron-transporting material.

[0078] When the square root of the electric field strength [V / cm] is 600, the electron mobility is 1×10 −７ cm ２ / Vs or more, 5×10 −５ cm ２ A material having a .DELTA. / Vs or less can be suitably used as a material having electron transport properties. This can suppress the electron transport properties in the electron transport layer. Alternatively, it can control the amount of electrons injected into the light-emitting layer. Alternatively, it can prevent the light-emitting layer from becoming an electron-excess state.

[0079] Examples of metal complexes include bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq ２ ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), and the like can be used.

[0080] Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include heterocyclic compounds having a polyazole skeleton, heterocyclic compounds having a diazine skeleton, heterocyclic compounds having a pyridine skeleton, and heterocyclic compounds having a triazine skeleton. In particular, heterocyclic compounds having a diazine skeleton or heterocyclic compounds having a pyridine skeleton are preferred because of their high reliability. Furthermore, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton have high electron transport properties and can reduce driving voltage.

[0081] Examples of heterocyclic compounds having a polyazole skeleton include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: O XD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2′,2″-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), and the like can be used.

[0082] Examples of heterocyclic compounds having a diazine skeleton include 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3′-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), and 2-[3′-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II). ]quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzo[h]quinazoline (abbreviation: 4,8mDBtP2Bqn), etc. can be used.

[0083] Examples of heterocyclic compounds having a pyridine skeleton include 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), and the like.

[0084] Examples of heterocyclic compounds having a triazine skeleton include 2-[3′-(9,9-dimethyl-9H-fluoren-2-yl)-1,1′-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 2-[(1,1′-biphenyl)-4-yl]-4-phenyl-6-[9,9′-spirobi(9H-fluoren)-2-yl]-1,3,5-triazine (abbreviation: BP- SFTzn), 2-{3-[3-(benzo“b”naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo“b”naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), and the like can be used.

[0085] [Material Having an Anthracene Skeleton] An organic compound having an anthracene skeleton can be used for the layer 113X(i,j). In particular, an organic compound including both an anthracene skeleton and a heterocyclic skeleton can be preferably used.

[0086] For example, an organic compound containing both an anthracene skeleton and a nitrogen-containing five-membered ring skeleton can be used. Alternatively, an organic compound containing both an anthracene skeleton and a nitrogen-containing five-membered ring skeleton containing two heteroatoms in the ring can be used. Specifically, a pyrazole ring, an imidazole ring, an oxazole ring, a thiazole ring, or the like can be suitably used as the heterocyclic skeleton.

[0087] For example, an organic compound containing both an anthracene skeleton and a nitrogen-containing six-membered ring skeleton can be used. Alternatively, an organic compound containing both an anthracene skeleton and a nitrogen-containing six-membered ring skeleton containing two heteroatoms in the ring can be used. Specifically, a pyrazine ring, a pyrimidine ring, a pyridazine ring, or the like can be suitably used as the heterocyclic skeleton.

[0088] [Configuration Example of Mixed Material] A material in which a plurality of substances are mixed can be used for the layer 113X(i,j). Specifically, a mixed material containing an alkali metal, an alkali metal compound, or an alkali metal complex, and a substance having an electron-transporting property can be used for the layer 113X(i,j). Note that in this specification and the like, the above-described light-emitting device may be referred to as a Recombination-Site Tailoring Injection structure (ReSTI structure).

[0089] The HOMO level of the material having an electron transport property is preferably −6.0 eV or higher. In addition, the alkali metal, alkali metal compound, or alkali metal complex is preferably present with a concentration difference in the thickness direction of the layer 113X(i,j).

[0090] For example, a metal complex containing an 8-hydroxyquinolinato structure can be used. Also, a methyl-substituted metal complex containing an 8-hydroxyquinolinato structure (for example, a 2-methyl-substituted or 5-methyl-substituted metal complex) can be used.

[0091] Examples of metal complexes containing an 8-hydroxyquinolinato structure include 8-hydroxyquinolinato-lithium (abbreviation: Liq), 8-hydroxyquinolinato-sodium (abbreviation: Naq), etc. In particular, complexes of monovalent metal ions, especially lithium complexes, are preferred, with Liq being more preferred.

[0092] <<Structure Example 1 of Layer 111X(i,j)>> For example, a light-emitting material, or a light-emitting material and a host material, can be used for the layer 111X(i,j). The layer 111X(i,j) can also be referred to as a light-emitting layer. Note that a structure in which the layer 111X(i,j) is disposed in a region where holes and electrons recombine can be preferred. This allows the energy generated by carrier recombination to be efficiently converted into light and emitted.

[0093] It is also preferable to arrange the layer 111X(i, j) away from metals used for electrodes, etc. This makes it possible to suppress the quenching phenomenon caused by metals used for electrodes, etc.

[0094] Furthermore, it is preferable to adjust the distance from a reflective electrode or the like to the layer 111X(i,j) and place the layer 111X(i,j) at an appropriate position according to the emission wavelength. This allows the interference phenomenon between the light reflected by the electrode or the like and the light emitted by the layer 111X(i,j) to be utilized to reinforce the amplitude. Furthermore, it is possible to strengthen the light spectrum by intensifying light of a specific wavelength. Furthermore, it is possible to obtain a vivid emission color with high intensity. In other words, a microresonator structure (microcavity) can be formed by placing the layer 111X(i,j) at an appropriate position between the electrodes or the like.

[0095] For example, the luminescent material can be a fluorescent material, a phosphorescent material, or a material exhibiting thermally activated delayed fluorescence (TADF) (also called a TADF material), which allows the energy generated by carrier recombination to be emitted as light ELX from the luminescent material (see FIG. 1).

[0096] [Fluorescent Material] A fluorescent material can be used for the layer 111X(i,j). For example, the fluorescent materials exemplified below can be used for the layer 111X(i,j). Note that the present invention is not limited to these, and various known fluorescent materials can be used for the layer 111X(i,j).

[0097] Specifically, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2′-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4′-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2′-bipyridine (abbreviation: PAPP2BPy), N,N′-diphenyl-N,N′-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N′-bis(3-methylphenyl)-N,N′-bis[3-(9-phenyl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: YGAPA), : 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N',N '-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02), etc. can be used.

[0098] In particular, condensed aromatic diamine compounds typified by pyrenediamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03 are preferred because they have high hole trapping properties and are excellent in luminous efficiency or reliability.

[0099] Also, N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl N-[9,10-bis(1,1′-biphenyl-2-yl)-2-anthryl]-N,N′,N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1′-biphenyl-2-yl)-2-anthryl]-N,N′,N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1′-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), coumarin 545T, N,N′-diphenylquinacridone (abbreviation: DPQd), rubrene, 5,12-bis(1,1′-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), and the like can be used.

[0100] Further, 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM3), (4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]ki] 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(di 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJ™), and the like can be used.

[0101] [Phosphorescent Material] A phosphorescent material can be used for the layer 111X(i,j). For example, the phosphorescent materials exemplified below can be used for the layer 111X(i,j). Note that the present invention is not limited thereto, and various known phosphorescent materials can be used for the layer 111X(i,j).

[0102] For example, organometallic iridium complexes having a 4H-triazole skeleton, organometallic iridium complexes having a 1H-triazole skeleton, organometallic iridium complexes having an imidazole skeleton, organometallic iridium complexes having a phenylpyridine derivative having an electron-withdrawing group as a ligand, organometallic iridium complexes having a pyrimidine skeleton, organometallic iridium complexes having a pyrazine skeleton, organometallic iridium complexes having a pyridine skeleton, rare earth metal complexes, platinum complexes, and the like can be used for the layer 111X(i, j).

[0103] [Phosphorescent Material (Blue)] Examples of organometallic iridium complexes having a 4H-triazole skeleton include tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp) ３ ]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz) ３ ]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b) ３ ]), etc. can be used.

[0104] Examples of organometallic iridium complexes having a 1H-triazole skeleton include tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp) ３ ]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me) ３ ]), etc. can be used.

[0105] Examples of organometallic iridium complexes having an imidazole skeleton include fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi) ３]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me) ３ ]), etc. can be used.

[0106] Examples of organometallic iridium complexes having a phenylpyridine derivative having an electron-withdrawing group as a ligand include bis[2-(4',6'-difluorophenyl)pyridinato-N,C ２’ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C ２’ ]iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C ２’} Iridium(III) picolinate (abbreviation: [Ir(CF ３ ppy) ２ (pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C ２’ ] Iridium (III) acetylacetonate (abbreviation: FIracac), etc. can be used.

[0107] These compounds exhibit blue phosphorescence and have a peak emission wavelength in the range of 440 nm to 520 nm.

[0108] [Phosphorescent Material (Green)] Examples of organometallic iridium complexes having a pyrimidine skeleton include tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ３ ]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ３ ]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ２ (acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ２(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm) ２ (acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm) ２ (acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm) ２ (acac)]), etc. can be used.

[0109] Examples of organometallic iridium complexes having a pyrazine skeleton include (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me) ２ (acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr) ２ (acac)]), etc. can be used.

[0110] Examples of organometallic iridium complexes having a pyridine skeleton include tris(2-phenylpyridinato-N,C ２’ ) Iridium(III) (abbreviation: [Ir(ppy) ３ ]), bis(2-phenylpyridinato-N,C ２’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy) ２ (acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq) ２ (acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq) ３ ]), tris(2-phenylquinolinato-N,C ２’ ) Iridium(III) (abbreviation: [Ir(pq) ３ ]), bis(2-phenylquinolinato-N,C ２’ ) iridium(III) acetylacetonate (abbreviation: [Ir(pq) ２(acac)]), [2-d3-methyl-8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d3) ２ (mbfpypy-d3)]), [2-d3-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy) ２ (mbfpypy-d3)]), etc. can be used.

[0111] The rare earth metal complexes include tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac) ３ (Phen)]), etc.

[0112] These compounds mainly exhibit green phosphorescence, with a peak emission wavelength between 500 nm and 600 nm. Organometallic iridium complexes having a pyrimidine skeleton are also remarkably superior in reliability and luminous efficiency.

[0113] [Phosphorescent material (red)] Examples of organometallic iridium complexes having a pyrimidine skeleton include (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm) ２ (dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm) ２ (dpm)]), bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(dpm) ２ (dpm)]), etc. can be used.

[0114] Examples of organometallic iridium complexes having a pyrazine skeleton include (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr) ２(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr) ２ (dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq) ２ (acac)]), etc. can be used.

[0115] Examples of organometallic iridium complexes having a pyridine skeleton include tris(1-phenylisoquinolinato-N,C ２’ ) Iridium(III) (abbreviation: [Ir(piq) ３ ]), bis(1-phenylisoquinolinato-N,C ２’ ) iridium(III) acetylacetonate (abbreviation: [Ir(piq) ２ (acac)]), etc. can be used.

[0116] Examples of rare earth metal complexes include tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM) ３ (Phen)]), tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA) ３ (Phen)]), etc. can be used.

[0117] As the platinum complex, 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP) and the like can be used.

[0118] These compounds exhibit red phosphorescence, with an emission peak at 600 nm to 700 nm. The organometallic iridium complexes having a pyrazine skeleton emit red light with a chromaticity suitable for use in display devices.

[0119] [Substances Exhibiting Thermally Activated Delayed Fluorescence (TADF)] A TADF material can be used for the layer 111X(i, j). For example, the TADF materials exemplified below can be used as the luminescent material. However, without being limited thereto, various known TADF materials can be used as the luminescent material.

[0120] TADF materials have a small difference between the S1 and T1 levels, allowing reverse intersystem crossing (upconversion) from a triplet excited state to a singlet excited state with a small amount of thermal energy. This allows efficient generation of a singlet excited state from a triplet excited state. Furthermore, the triplet excited energy can be converted into luminescence.

[0121] Furthermore, an exciplex (also called an exciplex) that forms an excited state with two types of substances has an extremely small difference between the S1 level and the T1 level, and functions as a TADF material that can convert triplet excitation energy into singlet excitation energy.

[0122] The T1 level can be determined by using a phosphorescence spectrum observed at low temperatures (e.g., 77 K to 10 K). When a tangent line is drawn at the base of the fluorescence spectrum on the short wavelength side of the TADF material, and the energy of the wavelength of the extrapolated line is defined as the S1 level, and when a tangent line is drawn at the base of the phosphorescence spectrum on the short wavelength side of the TADF material, and the energy of the wavelength of the extrapolated line is defined as the T1 level, the difference between S1 and T1 is preferably 0.3 eV or less, and more preferably 0.2 eV or less.

[0123] When a TADF material is used as a light-emitting material, the S1 level of the host material is preferably higher than the S1 level of the TADF material, and the T1 level of the host material is preferably higher than the T1 level of the TADF material.

[0124] For example, TADF materials can include fullerene and its derivatives, acridine and its derivatives, eosin derivatives, etc. Also, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), etc. can be used as TADF materials.

[0125] Specifically, protoporphyrin-tin fluoride complex (SnF), whose structural formula is shown below, ２ (Proto IX)), mesoporphyrin-tin fluoride complex (SnF ２ (Meso IX)), hematoporphyrin-tin fluoride complex (SnF ２ (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF ２ (Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF ２ (OEP)), etioporphyrin-tin fluoride complex (SnF ２ (Etio I)), octaethylporphyrin-platinum chloride complex (PtCl ２ OEP), etc. can be used.

[0126]

[0127] Furthermore, for example, a heterocyclic compound having one or both of a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring can be used as the TADF material.

[0128] Specifically, the structural formulas of these compounds are as follows: 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9′-phenyl-9H,9′H-3,3′-bicarbazole (abbreviation: PCCzTzn), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4 ,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10′H-spiro[acridin-9,9′-anthracene]-10′-one (abbreviation: ACRSA), and the like can be used.

[0129]

[0130] The heterocyclic compound has a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, and therefore has high electron transport and hole transport properties, and is therefore preferred. In particular, among skeletons having a π-electron-deficient heteroaromatic ring, pyridine skeletons, diazine skeletons (pyrimidine skeletons, pyrazine skeletons, pyridazine skeletons), and triazine skeletons are preferred because they are stable and reliable. In particular, benzofuropyrimidine skeletons, benzothienopyrimidine skeletons, benzofuropyrazine skeletons, and benzothienopyrazine skeletons are preferred because they have high acceptor properties and good reliability.

[0131] Among skeletons having a π-electron-rich heteroaromatic ring, it is preferable to have at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton because they are stable and reliable. Note that the dibenzofuran skeleton is preferable as the furan skeleton, and the dibenzothiophene skeleton is preferable as the thiophene skeleton. Furthermore, the indole skeleton, the carbazole skeleton, the indolocarbazole skeleton, the bicarbazole skeleton, and the 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton are particularly preferable as the pyrrole skeleton.

[0132] In addition, a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded is particularly preferred because the electron-donating property of the π-electron-rich heteroaromatic ring and the electron-accepting property of the π-electron-deficient heteroaromatic ring are both strong, and the energy difference between the S1 level and the T1 level is small, thereby enabling efficient thermally activated delayed fluorescence to be obtained. In addition, an aromatic ring bonded to an electron-withdrawing group such as a cyano group may be used instead of the π-electron-deficient heteroaromatic ring. In addition, an aromatic amine skeleton, a phenazine skeleton, or the like may be used as the π-electron-rich skeleton.

[0133] Furthermore, examples of the π-electron-deficient skeleton that can be used include a xanthene skeleton, a thioxanthene dioxide skeleton, an oxadiazole skeleton, a triazole skeleton, an imidazole skeleton, an anthraquinone skeleton, a boron-containing skeleton such as phenylborane or boranthrene, an aromatic ring or heteroaromatic ring having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, and a sulfone skeleton.

[0134] In this way, a π-electron-deficient skeleton and a π-electron-rich skeleton can be used in place of at least one of a π-electron-deficient heteroaromatic ring and a π-electron-rich heteroaromatic ring.

[0135] <<Structure Example 2 of Layer 111X(i,j)>> A material having carrier transport properties can be used as the host material. For example, a material having hole transport properties, a material having electron transport properties, a substance exhibiting thermally activated delayed fluorescence (TADF), a material having an anthracene skeleton, a mixed material, or the like can be used as the host material. Note that a structure using a material having a larger band gap than the light-emitting material contained in the layer 111X(i,j) is preferable. This can suppress energy transfer from excitons generated in the layer 111X(i,j) to the host material.

[0136] [Material having hole transport properties] A material having a hole mobility of 1×10 −６ cm ２ A material having a hole transporting property can be suitably used as a material having a hole transporting property.

[0137] For example, a material having a hole-transport property that can be used for the layer 112X(i,j) can be used for the layer 111X(i,j). Specifically, a material having a hole-transport property that can be used for a hole-transport layer can be used for the layer 111X(i,j).

[0138] [Electron-Transporting Material] For example, a metal complex or an organic compound having a π-electron-deficient heteroaromatic ring skeleton can be used as the electron-transporting material.

[0139] For example, a material having an electron-transporting property that can be used for the layer 113X(i,j) can be used for the layer 111X(i,j). Specifically, a material having an electron-transporting property that can be used for an electron-transport layer can be used for the layer 111X(i,j).

[0140] [Materials Having an Anthracene Skeleton] Organic compounds having an anthracene skeleton can be used as host materials. In particular, when a fluorescent material is used as the light-emitting material, organic compounds having an anthracene skeleton are suitable. This allows for the realization of light-emitting devices with good luminous efficiency and durability.

[0141] As the organic compound having an anthracene skeleton, an organic compound having a diphenylanthracene skeleton, particularly a 9,10-diphenylanthracene skeleton, is preferred because it is chemically stable. Furthermore, when the host material has a carbazole skeleton, it is preferred because it has improved hole injection and transport properties. In particular, when the host material contains a dibenzocarbazole skeleton, it is preferred because its HOMO level is shallower by about 0.1 eV than that of carbazole, making it easier for holes to enter, and it also has excellent hole transport properties and high heat resistance. From the viewpoint of hole injection and transport properties, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton.

[0142] Therefore, a substance having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton, a substance having both a 9,10-diphenylanthracene skeleton and a benzocarbazole skeleton, or a substance having both a 9,10-diphenylanthracene skeleton and a dibenzocarbazole skeleton is preferable as the host material.

[0143] For example, 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4′-yl}anthracene (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-phenyl-3-[4-(10-phenyl [4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), and the like can be used.

[0144] In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA exhibit very good properties.

[0145] [Substances Exhibiting Thermally Activated Delayed Fluorescence (TADF)] A TADF material can be used as a host material. The TADF material can convert triplet excitation energy into singlet excitation energy through reverse intersystem crossing. Furthermore, a TADF material preferably has a structure in which carriers recombine. This allows triplet excitation energy generated by carrier recombination to be efficiently converted into singlet excitation energy through reverse intersystem crossing. Furthermore, the excitation energy can be transferred to a light-emitting material. In other words, the TADF material functions as an energy donor, and the light-emitting material functions as an energy acceptor. This can improve the luminous efficiency of a light-emitting device.

[0146] A fluorescent material can be suitably used as the energy acceptor. In particular, when the S1 level of the TADF material is higher than the S1 level of the fluorescent material, high luminous efficiency can be obtained. Furthermore, it is more preferable that the T1 level of the TADF material is higher than the S1 level of the fluorescent material. Furthermore, it is more preferable that the T1 level of the TADF material is higher than the T1 level of the fluorescent material.

[0147] It is also preferable to use a TADF material that emits light that overlaps with the wavelength of the lowest energy absorption band of the fluorescent material, which facilitates the transfer of excitation energy from the TADF material to the fluorescent material and allows for efficient emission.

[0148] Furthermore, the fluorescent substance used as the energy acceptor preferably has a luminophore (a skeleton that causes light emission) and a protecting group around the luminophore. It is even more preferable to have multiple protecting groups. This can suppress the phenomenon in which triplet excitation energy generated in the TADF material is transferred to the triplet excitation energy of the fluorescent substance.

[0149] Here, the term "luminophore" refers to an atomic group (skeleton) that causes light emission in a fluorescent substance. The luminophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a fused aromatic ring or a fused heteroaromatic ring.

[0150] Examples of the fused aromatic ring or fused heteroaromatic ring include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, etc. In particular, fluorescent substances having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, or a naphthobisbenzofuran skeleton are preferred because of their high fluorescence quantum yield.

[0151] Furthermore, the protecting group surrounding the luminophore is preferably a substituent that does not have a π bond. For example, saturated hydrocarbons are preferred. Specifically, methyl groups, branched alkyl groups having 3 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms in a ring, and trialkylsilyl groups having 3 to 10 carbon atoms can be used as protecting groups. Substituents that do not have a π bond have poor carrier transport function. This allows the luminophore of the fluorescent material to be separated from the TADF material without significantly affecting carrier transport or carrier recombination, thereby optimizing the distance between the TADF material and the luminophore of the fluorescent material. Furthermore, energy transfer via the Dexter mechanism can be suppressed, while energy transfer via the Förster mechanism can be promoted.

[0152] For example, a TADF material that can be used as a light-emitting material can be used as a host material.

[0153] [Configuration Example 1 of Mixed Material] A material obtained by mixing a plurality of substances can be used as the host material. For example, a material having electron transport properties and a material having hole transport properties can be used as the mixed material. The weight ratio of the material having hole transport properties to the material having electron transport properties contained in the mixed material may be set to (material having hole transport properties / material having electron transport properties) = (1 / 19) or more and (19 / 1) or less. This allows the carrier transport properties of the layer 111X(i,j) to be easily adjusted. Furthermore, the recombination region can be easily controlled.

[0154] [Configuration Example 2 of Mixed Material] A material mixed with a phosphorescent material can be used as a host material. When a fluorescent material is used as an emitting material, the phosphorescent material can be used as an energy donor that provides excitation energy to the fluorescent material.

[0155] When a material containing a phosphorescent substance is used as a host material, the phosphorescent substance preferably has a protecting group, and more preferably has a plurality of protecting groups.

[0156] Furthermore, a substituent without a π bond is preferred as a protecting group. For example, saturated hydrocarbons are preferred. Specifically, a branched alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms in a ring, or a trialkylsilyl group having 3 to 10 carbon atoms can be used as a protecting group. Substituents without a π bond have poor carrier transport function. This allows the luminophores of the fluorescent material to be separated from the phosphorescent material, thereby achieving an appropriate distance between the phosphorescent material and the luminophores of the fluorescent material, without substantially affecting carrier transport or carrier recombination. Furthermore, energy transfer via the Dexter mechanism can be suppressed and energy transfer via the Förster mechanism can be promoted.

[0157] For the same reason, when a material containing a phosphorescent material is used as a host material, the fluorescent material preferably has a luminophore (a skeleton that causes luminescence) and protecting groups around the luminophore. It is even more preferable that the fluorescent material has multiple protecting groups.

[0158] [Structure Example 3 of Mixed Material] A mixed material containing a material that forms an exciplex can be used as a host material. For example, a material whose emission spectrum of the formed exciplex overlaps with the wavelength of the lowest-energy absorption band of the light-emitting material can be used as a host material. This makes energy transfer smooth, thereby improving light-emitting efficiency. Alternatively, driving voltage can be suppressed. With such a structure, light emission can be efficiently obtained using Exciplex-Triple Energy Transfer (ExTET), which is energy transfer from the exciplex to the light-emitting material (phosphorescent material).

[0159] At least one of the materials forming the exciplex can be a phosphorescent material, which allows for the utilization of reverse intersystem crossing or the efficient conversion of triplet excitation energy to singlet excitation energy.

[0160] As a combination of materials for forming an exciplex, it is preferable that the HOMO level of the material having hole transport properties is equal to or higher than the HOMO level of the material having electron transport properties. Alternatively, it is preferable that the LUMO level of the material having hole transport properties is equal to or higher than the LUMO level of the material having electron transport properties. This allows for efficient formation of an exciplex. The LUMO level and HOMO level of the material can be derived from electrochemical properties (reduction potential and oxidation potential). Specifically, the reduction potential and oxidation potential can be measured using cyclic voltammetry (CV) measurement.

[0161] The formation of exciplexes can be confirmed, for example, by comparing the emission spectra of a material having hole transport properties, a material having electron transport properties, and a mixed film obtained by mixing these materials, and observing the phenomenon in which the emission spectrum of the mixed film is shifted to longer wavelengths than the emission spectra of each material (or has a new peak on the longer wavelength side). Alternatively, the formation of exciplexes can be confirmed by comparing the transient photoluminescence (PL) of a material having hole transport properties, the transient PL of a material having electron transport properties, and a mixed film obtained by mixing these materials, and observing differences in transient response, such as the transient PL lifetime of the mixed film having a longer-lifetime component or a larger proportion of delayed components than the transient PL lifetimes of the individual materials. The above-mentioned transient PL may also be interpreted as transient electroluminescence (EL). In other words, the formation of exciplexes can also be confirmed by comparing the transient EL of a material having hole transport properties, the transient EL of a material having electron transport properties, and a mixed film obtained by mixing these materials, and observing the differences in transient response.

[0162] <<Configuration Example of Intermediate Layer 106X(i,j)>> The intermediate layer 106X(i,j) has a function of supplying electrons to one of the unit 103X(i,j) and the unit 103X2(i,j) and supplying holes to the other. The intermediate layer 106X(i,j) also includes unpaired electrons.

[0163] A single layer or a layer formed by stacking multiple layers can be used for the intermediate layer 106X(i,j). For example, the intermediate layer 106X(i,j) includes a layer 106X1(i,j) and a layer 106X2(i,j). The layer 106X2(i,j) is sandwiched between the layer 106X1(i,j) and the unit 103X2(i,j).

[0164] <<Configuration Example of Layer 106X2(i,j)>> For example, a material that supplies electrons to the anode side and holes to the cathode side when a voltage is applied can be used for the layer 106X2(i,j). Specifically, it can supply electrons to the unit 103X(i,j) arranged on the anode side and holes to the unit 103X2(i,j) arranged on the cathode side. In addition, the layer 106X2(i,j) can be referred to as a charge generation layer.

[0165] A substance having an acceptor property can be used for the layer 106X2(i,j). Alternatively, a composite material containing a plurality of kinds of substances can be used for the layer 106X2(i,j).

[0166] [Substance Having Acceptor Property] Organic compounds and inorganic compounds can be used as the substance having acceptor property. The substance having acceptor property can extract electrons from the adjacent hole transport layer or the material having hole transport property by applying an electric field.

[0167] For example, a compound having an electron-withdrawing group (a halogen group or a cyano group) can be used as a substance having acceptor properties. Note that organic compounds having acceptor properties are easy to deposit and form into films. This can improve the productivity of light-emitting devices.

[0168] Specifically, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F ４ -TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile, and the like can be used.

[0169] In particular, a compound in which an electron-withdrawing group is bonded to a condensed aromatic ring having a plurality of heteroatoms, such as HAT-CN, is thermally stable and is therefore preferred.

[0170] [3] Radialene derivatives having an electron-withdrawing group (particularly a halogen group such as a fluoro group or a cyano group) are also preferred because they have very high electron-accepting properties.

[0171] Specifically, α,α',α''-1,2,3-cyclopropane triylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropane triylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], α,α',α''-1,2,3-cyclopropane triylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile], and the like can be used.

[0172] Furthermore, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, or the like can be used as the substance having acceptor properties.

[0173] In addition, phthalocyanine (abbreviation: H ２ and compounds having an aromatic amine skeleton such as 4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB) and N,N′-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (abbreviation: DNTPD).

[0174] Furthermore, polymers such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS) can also be used.

[0175] [Structure Example 1 of Composite Material] For example, a composite material including a substance having an acceptor property and a material having a hole-transport property can be used for the layer 106X2(i,j).

[0176] For example, compounds having an aromatic amine skeleton, carbazole derivatives, aromatic hydrocarbons, aromatic hydrocarbons having a vinyl group, and polymeric compounds (oligomers, dendrimers, polymers, etc.) can be used as the material having hole transport properties for the composite material. −６ cm ２ A material having a hole transporting property can be suitably used as the material of the composite material.

[0177] Furthermore, a substance having a relatively deep HOMO level can be preferably used as the material having hole-transporting properties of the composite material. Specifically, the HOMO level is preferably −5.7 eV or more and −5.3 eV or less. This can facilitate injection of holes into the unit 103X2(i,j). Alternatively, it can facilitate injection of holes into the layer 112X2(i,j). Alternatively, it can improve the reliability of the light-emitting device.

[0178] Examples of compounds having an aromatic amine skeleton that can be used include N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B).

[0179] Examples of the carbazole derivative include 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole, and carbazole (abbreviation: PCzPCN1), 4,4′-di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, and the like can be used.

[0180] Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert-butyl-9,10 10,10'-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, pentacene, coronene, and the like can be used.

[0181] Examples of aromatic hydrocarbons having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA), and the like.

[0182] Examples of polymer compounds that can be used include poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD).

[0183] For example, a substance having a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, or an anthracene skeleton can be suitably used as a material having hole transport properties for the composite material. Furthermore, a substance having an aromatic amine with a substituent containing a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine with a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group can be used as a material having hole transport properties for the composite material. The use of a substance having an N,N-bis(4-biphenyl)amino group can improve the reliability of the light-emitting device.

[0184] Examples of these materials include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4′-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4″-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2 -d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl -4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB-0 3), 4,4'-diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-Diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4′-[4′-(3-phenyl-9H-carbazol-9-yl)phenyl]tris(αNBB1BP), 4,4′-[4 ... 1,1'-biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-diphenyl-4'-(2-naphthyl)-4''-{9-(4-biphenylyl)carbazole)}triphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N-bis(4-biphenylyl)-9 ,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(1,1'-biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(1,1'-biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(4-biphenyl)-N-(dibenzofuran-4-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenyl 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), N,N-bis(9,9- N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, etc. can be used.

[0185] <<Configuration Example of Layer 106X1(i,j)>> For example, a material having electron transport properties can be used for the layer 106X1(i,j). The layer 106X1(i,j) can also be referred to as an electron relay layer. By using the layer 106X1(i,j), the layer in contact with the anode side of the layer 106X1(i,j) can be spaced apart from the layer in contact with the cathode side of the layer 106X1(i,j). The interaction between the layer in contact with the anode side of the layer 106X1(i,j) and the layer in contact with the cathode side of the layer 106X1(i,j) can be reduced. Furthermore, electrons can be smoothly supplied to the layer in contact with the anode side of the layer 106X1(i,j).

[0186] A substance having a LUMO level between the LUMO level of a substance having acceptor properties included in a layer in contact with the anode side of the layer 106X1(i,j) and the LUMO level of a substance included in a layer in contact with the cathode side of the layer 106X1(i,j) can be suitably used for the layer 106X1(i,j).

[0187] For example, a material having a LUMO level in the range of −5.0 eV or more, preferably −5.0 eV or more and −3.0 eV or less, more preferably −4.0 eV or more and −3.3 eV or less can be used for the layer 106X1(i,j).

[0188] Alternatively, a material having an unpaired electron can be used. Specifically, a phthalocyanine-based material can be used for the layer 106X1(i,j). Alternatively, a metal complex having a metal-oxygen bond and an aromatic ligand can be used for the layer 106X1(i,j).

[0189] <<Configuration Example 1 of Unit 103X2(i,j)>> The unit 103X2(i,j) has a single-layer structure or a laminated structure. For example, the unit 103X2(i,j) has a layer 111X2(i,j), a layer 112X2(i,j), and a layer 113X2(i,j) (see FIG. 1 ). The unit 103X(i,j) has a function of emitting light ELX.

[0190] Layer 111X2(i,j) comprises an area sandwiched between layer 112X2(i,j) and layer 113X2(i,j), layer 112X2(i,j) comprises an area sandwiched between intermediate layer 106X(i,j) and layer 111X2(i,j), and layer 113X2(i,j) comprises an area sandwiched between electrode 552X(i,j) and layer 111X2(i,j).

[0191] For example, the unit 103X2(i, j) can be formed of a layer selected from functional layers such as a light-emitting layer, a hole-transporting layer, an electron-transporting layer, a carrier-blocking layer, etc. Also, the unit 103X2(i, j) can be formed of a layer selected from functional layers such as a hole-injecting layer, an electron-injecting layer, an exciton-blocking layer, and a charge-generating layer, etc.

[0192] The configuration that can be used for the unit 103X(i,j) can also be used for the unit 103X2(i,j).

[0193] For example, the same configuration as that employed in unit 103X(i,j) can be used in unit 103X2(i,j). Furthermore, a configuration in which the thickness of a portion of unit 103X(i,j) is changed can be used in unit 103X2(i,j). This allows the distance from a reflective electrode or the like to layer 111X2(i,j) to be adjusted. Furthermore, by utilizing the interference phenomenon between light reflected by an electrode or the like and light emitted by layer 111X2(i,j), the amplitudes can be reinforced. Furthermore, a microresonator structure (microcavity) can be configured.

[0194] <Configuration example 2 of unit 103X2(i,j)> For example, a configuration that emits light of the same hue as the light ELX emitted by unit 103X(i,j) can be used for unit 103X2(i,j), although it is different from the configuration adopted for unit 103X(i,j).

[0195] Specifically, a different structure from that employed in the layer 111X(i,j) can be used in the layer 111X2(i,j), for example, a fluorescent material can be used in one layer and a phosphorescent material can be used in the other.

[0196] More specifically, a different configuration may be used for the layer 112X2(i,j) than that employed for the layer 112X(i,j).

[0197] Specifically, a different configuration from that employed in the layer 113X(i,j) can be used in the layer 113X2(i,j).

[0198] <Configuration Example 3 of Unit 103X2(i,j)> For example, a configuration that emits light of a different hue from the light ELX emitted by unit 103X(i,j) can be used for unit 103X2(i,j).

[0199] Specifically, a unit 103X(i, j) that emits yellow light and a unit 103X2(i, j) that emits blue light can be used. Alternatively, a unit 103X(i, j) that emits red light and green light and a unit 103X2(i, j) that emits blue light can be used. This makes it possible to provide a light-emitting device that emits light of a desired color. For example, it is possible to provide a light-emitting device that emits white light.

[0200] <Configuration example 2 of light-emitting device 550X(i,j)> Furthermore, the light-emitting device 550X(i,j) has an electrode 551X(i,j), an electrode 552X(i,j), a unit 103X(i,j), a unit 103X2(i,j), an intermediate layer 106X(i,j), and a layer 105X2(i,j).

[0201] The layer 105X2(i,j) comprises a region sandwiched between the unit 103X(i,j) and the intermediate layer 106X(i,j).

[0202] <<Configuration Example of Layer 105X2(i,j)>> For example, a material having electron injection properties can be used for the layer 105X2(i,j). The layer 105X2(i,j) can also be referred to as an electron injection layer.

[0203] The layer 105X2(i, j) contains unpaired electrons, and the unpaired electrons are measured by an electron spin resonance (ESR) apparatus to determine whether the unpaired electrons are 1×10 １６ spins / cm ３ 1x10 or more １８ spins / cm ３The unpaired electron can be observed at the following spin density: The unpaired electron has a g value in the range of 2.003 to 2.004.

[0204] Furthermore, the unpaired electrons can be observed in air with a spin density of 50% or more of the initial value after 24 hours using an electron spin resonance (ESR) spectrometer. Note that the elapsed time can be, for example, the time after the sealing structure of the manufactured light-emitting device is destroyed.

[0205] This also reduces the barrier between the intermediate layer 106X(i,j) and the layer 105X2(i,j) when electrons are injected from the intermediate layer 106X(i,j) to the layer 105X2(i,j). This also increases the degree of freedom in processing steps that can be applied after the layer 105X2(i,j) is formed. This also increases the resistance to, for example, a heat treatment step. This also increases the resistance to, for example, a chemical treatment step. After the intermediate layer 106X(i,j) is formed on the layer 105X2(i,j), the intermediate layer 106X(i,j) and the layer 105X2(i,j) can be processed into a predetermined shape using photolithography. Furthermore, for example, after forming the unit 103X2(i,j), the unit 103X2(i,j), the intermediate layer 106X(i,j), the layer 105X2(i,j), and the unit 103X2(i,j) can be processed into a predetermined shape using a photolithography method, thereby providing a novel display device that is highly convenient, useful, and reliable.

[0206] For example, a mixed material containing an organic compound having electron transport properties and an inorganic compound having donor properties can be used for the layer 105X2(i,j).

[0207] [Structure Example 1 of Organic Compound Having Electron Transport Property] An organic compound having an unshared electron pair can be used as an organic compound having electron transport property. The organic compound interacts with an inorganic compound having donor property to form a half-occupied orbital.

[0208] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviation: BPhen), 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), etc. can be used as the organic compound having an unshared electron pair. Note that NBPhen has a higher glass transition temperature (Tg) and is superior in heat resistance compared to BPhen.

[0209] [Structure Example 2 of Organic Compound Having Electron-Transporting Property] An organic compound having an electron-deficient heteroaromatic ring can be used for the layer 105X2(i,j). Specifically, a compound having at least one of a pyridine ring, a diazine ring (a pyrimidine ring, a pyrazine ring, or a pyridazine ring), and a triazine ring can be used.

[0210] Furthermore, an organic compound having a lowest unoccupied molecular orbital (LUMO) level in the range of −3.6 eV to −2.3 eV can be used for the layer 105X2(i, j). Note that the HOMO level and LUMO level of an organic compound can generally be estimated by cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, or the like.

[0211] [Configuration Example 1 of Inorganic Compound] An inorganic compound containing a metal element and oxygen can be used as the inorganic compound having donor properties. For example, an inorganic compound containing an alkali metal and oxygen can be used. Also, an inorganic compound containing an alkaline earth metal and oxygen can be used. In particular, an inorganic compound containing Li and oxygen can be preferably used.

[0212] This makes it possible to reduce the driving voltage of the light-emitting device and the power consumption of the display device, thereby providing a novel display device that is highly convenient, useful, and reliable.

[0213] <Configuration Example 3 of Light-Emitting Device 550X(i,j)> The light-emitting device 550X(i,j) has an electrode 551X(i,j), an electrode 552X(i,j), a unit 103X(i,j), and a layer 104X(i,j).

[0214] The layer 104X(i,j) comprises a region sandwiched between the electrode 551X(i,j) and the unit 103X(i,j).

[0215] <<Structure Example of the Electrode 551X(i,j)>> For example, a conductive material can be used for the electrode 551X(i,j). Specifically, a single layer or a stacked layer of a film containing a metal, an alloy, or a conductive compound can be used for the electrode 551X(i,j).

[0216] For example, a film that efficiently reflects light can be used for the electrode 551X(i,j). Specifically, a film of a metal such as an alloy containing silver and copper, an alloy containing silver and palladium, or aluminum can be used for the electrode 551X(i,j).

[0217] Furthermore, for example, a metal film that transmits part of the light and reflects the other part of the light can be used for the electrode 551X(i,j). This allows a microresonator structure (microcavity) to be provided in the light-emitting device 550X(i,j). Alternatively, light of a specific wavelength can be extracted more efficiently than other light. Alternatively, light with a narrow spectral half-width can be extracted. Alternatively, light of a vivid color can be extracted.

[0218] For example, a film that transmits visible light can be used for the electrode 551X(i,j). Specifically, a single layer or stacked layer of a metal film, an alloy film, a conductive oxide film, or the like that is thin enough to transmit light can be used for the electrode 551X(i,j).

[0219] In particular, a material having a work function of 4.0 eV or more can be suitably used for the electrode 551X(i, j).

[0220] For example, a conductive oxide containing indium can be used, such as indium oxide, indium oxide-tin oxide (abbreviation: ITO), indium oxide-tin oxide containing silicon or silicon oxide (abbreviation: ITSO), indium oxide-zinc oxide, or indium oxide containing tungsten oxide and zinc oxide (abbreviation: IWZO).

[0221] Alternatively, for example, a conductive oxide containing zinc can be used, such as zinc oxide, zinc oxide doped with gallium, or zinc oxide doped with aluminum.

[0222] Alternatively, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or a nitride of a metal material (e.g., titanium nitride) can be used. Alternatively, graphene can be used.

[0223] <<Structure Example of Layer 104X(i,j)>> For example, a material having a hole injection property can be used for the layer 104X(i,j). The layer 104X(i,j) can also be referred to as a hole injection layer.

[0224] Specifically, a substance having an acceptor property can be used for the layer 104X(i,j). Alternatively, a composite material containing a plurality of substances can be used for the layer 104X(i,j). This can facilitate hole injection from the electrode 551X(i,j), for example. Alternatively, the driving voltage of the light-emitting device can be reduced.

[0225] [Substance Having Acceptor Property] For example, a substance having acceptor property that can be used for the layer 106X2(i,j) can be used for the layer 104X(i,j).

[0226] [Structure Example 1 of Composite Material] For example, a composite material containing a substance having an acceptor property and a material having a hole-transport property can be used for the layer 104X(i,j). Specifically, the composite material that can be used for the layer 106X2(i,j) can be used for the layer 104X(i,j). Note that the layer 106X2(i,j) containing the composite material has a density of 1×10 ２ [Ω・cm] or more 1×10 ８ It has an electrical resistivity of [Ω·cm] or less.

[0227] This can facilitate injection of holes into the unit 103X(i, j), or into the layer 112X(i, j), or can improve the reliability of the light-emitting device.

[0228] Note that when a mixed material containing an alkali metal, an alkali metal compound, or an alkali metal complex and a substance having electron-transporting properties is used for the layer 113X(i,j), the composite material can be suitably used for the layer 104X(i,j). In particular, a composite material containing a material having hole-transporting properties and a relatively deep HOMO level HM1 of −5.7 eV or more and −5.4 eV or less and a substance having acceptor properties can be used for the layer 104X(i,j). This can improve the reliability of the light-emitting device.

[0229] Alternatively, the mixed material may be used for the layer 113X(i,j), the composite material may be used for the layer 104X(i,j), and a substance having a HOMO level HM2 in the range of −0.2 eV to 0 eV with respect to the relatively deep HOMO level HM1 may be used for the layer 112X(i,j). This may further improve the reliability of the light-emitting device.

[0230] [Configuration Example 2 of Composite Material] For example, a composite material containing a substance having acceptor properties, a material having hole-transport properties, and an alkali metal fluoride or an alkaline earth metal fluoride can be used as a material having hole-injection properties. In particular, a composite material containing fluorine atoms at an atomic ratio of 20% or more can be preferably used. This can reduce the refractive index of the layer 104X(i,j). Alternatively, a layer with a low refractive index can be formed inside the light-emitting device. Alternatively, the external quantum efficiency of the light-emitting device can be improved.

[0231] <Configuration Example 4 of Light-Emitting Device 550X(i,j)> The light-emitting device 550X(i,j) also has an electrode 551X(i,j), an electrode 552X(i,j), a unit 103X2(i,j), and a layer 105X(i,j).

[0232] The electrode 552X(i,j) has an area overlapping with the electrode 551X(i,j), the unit 103X2(i,j) has an area sandwiched between the electrode 552X(i,j) and the electrode 551X(i,j), and the layer 105X(i,j) has an area sandwiched between the electrode 552X(i,j) and the unit 103X2(i,j).

[0233] <<Structure Example of the Electrode 552X(i,j)>> For example, a conductive material can be used for the electrode 552X(i,j). Specifically, a single layer or a stacked layer of a film containing a metal, an alloy, or a conductive compound can be used for the electrode 552X(i,j).

[0234] For example, a material that can be used for the electrode 551X(i,j) can be used for the electrode 552X(i,j). In particular, a material having a work function smaller than that of the electrode 551X(i,j) can be suitably used for the electrode 552X(i,j). Specifically, a material having a work function of 3.8 eV or less is preferred.

[0235] For example, elements belonging to Group 1 of the periodic table, elements belonging to Group 2 of the periodic table, rare earth metals, and alloys containing these can be used for the electrode 552X(i,j).

[0236] Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), strontium (Sr), europium (Eu), ytterbium (Yb), and alloys containing these (MgAg, AlLi) can be used for the electrode 552X(i, j).

[0237] <<Configuration Example of Layer 105X(i,j)>> For example, a material having an electron injection property can be used for the layer 105X(i,j). The layer 105X(i,j) can also be referred to as an electron injection layer.

[0238] Specifically, a substance having donor properties can be used for the layer 105X(i,j). Alternatively, a composite material of a substance having donor properties and a material having electron-transporting properties can be used for the layer 105X(i,j). Alternatively, an electride can be used for the layer 105X(i,j). This can facilitate electron injection from the electrode 552X(i,j), for example. Alternatively, not only a material having a low work function but also a material having a high work function can be used for the electrode 552X(i,j). Alternatively, a material for the electrode 552X(i,j) can be selected from a wide range of materials regardless of the work function. Specifically, Al, Ag, ITO, indium oxide-tin oxide containing silicon or silicon oxide, or the like can be used for the electrode 552X(i,j). Alternatively, the driving voltage of the light-emitting device can be reduced.

[0239] [Substance Having Donor Properties] For example, alkali metals, alkaline earth metals, rare earth metals, or compounds thereof (oxides, halides, carbonates, etc.) can be used as the substance having donor properties. Alternatively, organic compounds such as tetrathianaphthacene (abbreviation: TTN), nickelocene, and decamethylnickelocene can also be used as the substance having donor properties.

[0240] Examples of alkali metal compounds (including oxides, halides, and carbonates) that can be used include lithium oxide, lithium fluoride (LiF), cesium fluoride (CsF), lithium carbonate, cesium carbonate, and 8-hydroxyquinolinato-lithium (abbreviated as Liq).

[0241] Alkaline earth metal compounds (including oxides, halides, and carbonates) include calcium fluoride (CaF ２ ), etc. can be used.

[0242] [Configuration Example 1 of Composite Material] A composite material of a plurality of substances can be used as a material having an electron injecting property. For example, a material having a donor property and a material having an electron transport property can be used as a composite material.

[0243] [Electron-Transporting Material] For example, a metal complex or an organic compound having a π-electron-deficient heteroaromatic ring skeleton can be used as the electron-transporting material.

[0244] Specifically, a material having an electron transporting property that can be used for the unit 103X(i, j) can be used for the composite material.

[0245] [Configuration Example 2 of Composite Material] A microcrystalline alkali metal fluoride and a material having an electron-transporting property can be used for the composite material. Alternatively, a microcrystalline alkaline earth metal fluoride and a material having an electron-transporting property can be used for the composite material. In particular, a composite material containing 50 wt % or more of an alkali metal fluoride or an alkaline earth metal fluoride can be preferably used. Alternatively, a composite material containing an organic compound having a bipyridine skeleton can be preferably used. This can reduce the refractive index of the layer 105. Alternatively, the external quantum efficiency of the light-emitting device can be improved.

[0246] [Structure Example 3 of Composite Material] For example, a composite material containing a first organic compound having an unshared electron pair and a first metal can be used for the layer 105X(i,j). The sum of the number of electrons in the first organic compound and the number of electrons in the first metal is preferably an odd number. The molar ratio of the first metal to 1 mole of the first organic compound is preferably 0.1 to 10, more preferably 0.2 to 2, and even more preferably 0.2 to 0.8.

[0247] This allows the first organic compound having an unshared electron pair to interact with the first metal to form a Singly Occupied Molecular Orbital (SOMO). Furthermore, when electrons are injected from the electrode 552X(i,j) to the layer 105X(i,j), the barrier between them can be reduced. Furthermore, since the first metal has low reactivity with water or oxygen, the moisture resistance of the light-emitting device can be improved.

[0248] The spin density measured by electron spin resonance (ESR) is preferably 1×10 １６ spins / cm ３ or more, more preferably 5 × 10 １６ spins / cm ３ More preferably, 1×10 １７ spins / cm ３ The above composite material can be used for the layer 105X(i,j).

[0249] [Organic Compound Having an Unshared Electron Pair] For example, a material having electron transport properties can be used as an organic compound having an unshared electron pair. For example, a compound having an electron-deficient heteroaromatic ring can be used. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), and a triazine ring can be used. This can reduce the driving voltage of the light-emitting device.

[0250] The organic compound having an unshared electron pair preferably has a lowest unoccupied molecular orbital (LUMO) of −3.6 eV to −2.3 eV. Generally, the HOMO level and LUMO level of an organic compound can be estimated by cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, or the like.

[0251] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviation: BPhen), 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), etc. can be used as the organic compound having an unshared electron pair. Note that NBPhen has a higher glass transition temperature (Tg) and is superior in heat resistance compared to BPhen.

[0252] Furthermore, for example, copper phthalocyanine, which has an odd number of electrons, can be used as the organic compound having an unshared electron pair.

[0253] [First Metal] For example, when the number of electrons in the first organic compound having an unshared electron pair is even, a composite material of a metal belonging to an odd group in the periodic table and the first organic compound can be used for the layer 105X(i,j).

[0254] For example, manganese (Mn), a Group 7 metal, cobalt (Co), a Group 9 metal, copper (Cu), silver (Ag), and gold (Au), which are Group 11 metals, and aluminum (Al) and indium (In), which are Group 13 metals, belong to odd-numbered groups in the periodic table. The elements of Group 11 have lower melting points than the elements of Groups 7 and 9, making them suitable for vacuum deposition. Ag is particularly preferred due to its low melting point.

[0255] By using Ag for the electrode 552X(i,j) and the layer 105X(i,j), the adhesion between the layer 105X(i,j) and the electrode 552X(i,j) can be improved.

[0256] When the number of electrons in the first organic compound having the lone electron pair is odd, a composite material of the first metal and the first organic compound that belong to an even group in the periodic table can be used for the layer 105X(i,j). For example, iron (Fe), a metal in Group 8, belongs to an even group in the periodic table.

[0257] [Electride] For example, a substance in which electrons are added to a mixed oxide of calcium and aluminum at a high concentration can be used as a material having electron injection properties.

[0258] Note that this embodiment mode can be appropriately combined with other embodiment modes described in this specification.

[0259] Embodiment 2 In this embodiment, a structure of a display device according to one embodiment of the present invention will be described with reference to FIGS.

[0260] 2A and 2B are diagrams illustrating a structure of a display device according to one embodiment of the present invention, in which Fig. 2A is a top view illustrating a display device according to one embodiment of the present invention, and Fig. 2B is a top view illustrating a part of the display device.

[0261] FIG. 3 is a circuit diagram illustrating a pixel of a display device according to one embodiment of the present invention.

[0262] 4A and 4B are cross-sectional views illustrating a structure of a display device according to one embodiment of the present invention. Fig. 4A illustrates a cross section along the cutting lines a1-a2 and a3-a4 and a pair of pixels 703(i, j) shown in Fig. 2A. Fig. 4B is a cross-sectional view illustrating a transistor that can be used in the display device according to one embodiment of the present invention.

[0263] 5A and 5B are cross-sectional views of the pixel taken along the line Y1-Y2 and the line Y3-Y4, respectively, and FIG. 5C is a cross-sectional view of the pixel taken along the line X1-X2.

[0264] FIG. 6 is a cross-sectional view illustrating a structure of a set of pixels in a display device according to one embodiment of the present invention.

[0265] In this specification, variables that take on integer values ​​of 1 or greater may be used as symbols. For example, (p) including a variable p that takes on an integer value of 1 or greater may be used as part of a symbol specifying any one of up to p components. Also, for example, (m, n) including variables m and n that take on integer values ​​of 1 or greater may be used as part of a symbol specifying any one of up to m×n components.

[0266] In this specification, etc., a device fabricated using a metal mask or an FMM (fine metal mask, high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. Also, in this specification, etc., a device fabricated without using a metal mask or an FMM may be referred to as a device with an MML (metal maskless) structure.

[0267] In this specification and the like, a structure in which different light-emitting layers are formed or different light-emitting layers are painted for each color light-emitting device (here, blue (B), green (G), and red (R)) may be referred to as an SBS (Side By Side) structure. In this specification and the like, a light-emitting device that can emit white light may be referred to as a white light-emitting device. In addition, a white light-emitting device can be combined with a colored layer (for example, a color filter) to realize a full-color display device.

[0268] Furthermore, light-emitting devices can be broadly divided into single structures and tandem structures. A single-structure device has one light-emitting unit between a pair of electrodes, and the light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, two or more light-emitting layers may be selected so that the light emitted from each of the two or more light-emitting layers has a complementary color relationship. For example, by making the emission color of the first light-emitting layer and the emission color of the second light-emitting layer complementary, a configuration in which the entire light-emitting device emits white light can be obtained. The same applies to light-emitting devices having three or more light-emitting layers.

[0269] A tandem-structure device preferably has two or more light-emitting units between a pair of electrodes, and each light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, light from the light-emitting layers of the light-emitting units may be combined to obtain white light emission. The configuration for obtaining white light emission is the same as that of the single-structure device. In a tandem-structure device, it is preferable to provide an intermediate layer such as a charge-generating layer between the light-emitting units.

[0270] Furthermore, when comparing the above-described white light-emitting device (single structure or tandem structure) with a light-emitting device having an SBS structure, the light-emitting device having an SBS structure can reduce power consumption compared to the white light-emitting device. When it is desired to reduce power consumption, it is preferable to use a light-emitting device having an SBS structure. On the other hand, the manufacturing process of a white light-emitting device is simpler than that of a light-emitting device having an SBS structure, and therefore the manufacturing cost can be reduced or the manufacturing yield can be increased, making it preferable.

[0271] <Configuration Example 1 of Display Device 700> The display device 700 includes a display area 231, which includes a set of pixels 703(i, j) (see FIG. 2A ). The display area 231 also includes a set of pixels 703(i+1, j) adjacent to the set of pixels 703(i, j) (see FIG. 2B ).

[0272] <Configuration Example 1 of Display Area 231> For example, the display area 231 has a set of 500 or more pixels per inch. Also, the display area 231 has a set of 1,000 or more pixels per inch, preferably 5,000 or more pixels, and more preferably 10,000 or more pixels per inch. This can reduce the screen door effect when used in a goggle-type display device, for example.

[0273] <<Configuration Example 2 of Display Area 231>> The display area 231 includes a plurality of pixels. For example, the display area 231 includes 7,600 or more pixels in the row direction and 4,300 or more pixels in the column direction. Specifically, the display area 231 includes 7,680 pixels in the row direction and 4,320 pixels in the column direction. This allows for the display of a high-resolution image.

[0274] <<Configuration Example 1 of Pixel 703(i,j)>> A plurality of pixels can be used for pixel 703(i,j) (see FIG. 2B ). For example, a plurality of pixels that display colors with different hues can be used. Each of the plurality of pixels can be referred to as a sub-pixel. Alternatively, a set of a plurality of sub-pixels can be referred to as a pixel.

[0275] This allows the colors displayed by the plurality of pixels to be mixed by additive or subtractive color mixing, or allows colors of hues that cannot be displayed by individual pixels to be displayed.

[0276] Specifically, pixel 702B(i,j) displaying blue, pixel 702G(i,j) displaying green, and pixel 702R(i,j) displaying red can be used as pixel 703(i,j). Furthermore, pixel 702B(i,j), pixel 702G(i,j), and pixel 702R(i,j) can each be referred to as a sub-pixel.

[0277] Furthermore, for example, a pixel that displays white or the like can be added to the above set and used as pixel 703(i,j). Also, a pixel that displays cyan, a pixel that displays magenta, and a pixel that displays yellow can be used as pixel 703(i,j).

[0278] Furthermore, for example, a pixel that emits infrared light can be added to the above set and used as pixel 703(i,j). Specifically, a pixel that emits light including light having a wavelength of 650 nm or more and 1000 nm or less can be used as pixel 703(i,j).

[0279] <Configuration Example 2 of Display Device 700> The display device 700 includes a light-emitting device 550G(i,j) and a light-emitting device 550B(i,j) (see FIG. 4A ). The display device 700 also includes a base material 510, a functional layer 520, an insulating film 705, and a base material 770.

[0280] Light-emitting device 550G(i,j) and light-emitting device 550B(i,j) are sandwiched between substrate 770 and functional layer 520.

[0281] The functional layer 520 is sandwiched between the substrate 770 and the substrate 510. The insulating film 705 is also sandwiched between the functional layer 520 and the substrate 770, and the insulating film 705 has the function of bonding the functional layer 520 and the substrate 770 together.

[0282] The functional layer 520 includes a pixel circuit 530G(i,j) and a pixel circuit 530B(i,j). The pixel circuit 530G(i,j) is electrically connected to the light-emitting device 550G(i,j) via an opening 591G, and the pixel circuit 530B(i,j) is electrically connected to the light-emitting device 550B(i,j) via an opening 591B.

[0283] The display device displays information through the base material 770 (see FIG. 4A ). In other words, the light-emitting device 550G(i, j) emits light in a direction where the functional layer 520 is not disposed. The light-emitting device 550G(i, j) can also be called a top-emission light-emitting device.

[0284] The substrate 510 includes a drive circuit GD and terminals 519B, as well as a drive circuit SD (not shown).

[0285] <<Configuration Example of the Driver Circuit GD>> The driver circuit GD has a function of supplying a first selection signal and a second selection signal. For example, the driver circuit GD is electrically connected to the conductive film G1(i) and supplies the first selection signal, and is electrically connected to the conductive film G2(i) and supplies the second selection signal.

[0286] <<Configuration Example of Driver Circuit SD>> The driver circuit SD has a function of supplying an image signal and a control signal, and the control signal includes a first level and a second level. For example, the driver circuit SD is electrically connected to the conductive film S1g(j) and supplies the image signal, and is electrically connected to the conductive film S2g(j) and supplies the control signal.

[0287] <Configuration example 3 of display device 700> The display device 700 has a conductive film G1(i), a conductive film G2(i), a conductive film S1g(j), a conductive film S2g(j), a conductive film ANO, and a conductive film VCOM2 (see FIG. 3).

[0288] For example, the conductive film G1(i) is supplied with a first selection signal, the conductive film G2(i) is supplied with a second selection signal, the conductive film S1g(j) is supplied with an image signal, and the conductive film S2g(j) is supplied with a control signal.

[0289] <<Configuration Example 2 of Pixel 703(i,j)>> A set of pixels 703(i,j) includes a pixel 702G(i,j) (see FIG. 2B). The pixel 702G(i,j) includes a pixel circuit 530G(i,j) and a light-emitting device 550G(i,j) (see FIG. 3).

[0290] <<Configuration Example 1 of Pixel Circuit 530G(i,j)>> The pixel circuit 530G(i,j) is supplied with a first selection signal, and the pixel circuit 530G(i,j) acquires an image signal based on the first selection signal. For example, the first selection signal can be supplied using the conductive film G1(i) (see FIG. 3 ). Alternatively, the image signal can be supplied using the conductive film S1g(j). Note that the operation of supplying the first selection signal and causing the pixel circuit 530G(i,j) to acquire the image signal can be referred to as "writing."

[0291] <<Configuration Example 2 of Pixel Circuit 530G(i,j)>> The pixel circuit 530G(i,j) includes a switch SW21, a switch SW22, a transistor M21, a capacitor C21, and a node N21 (see FIG. 3). The pixel circuit 530G(i,j) also includes a node N22, a capacitor C22, and a switch SW23.

[0292] The transistor M21 has a gate electrode electrically connected to the node N21, a first electrode electrically connected to the light-emitting device 550G(i, j), and a second electrode electrically connected to the conductive film ANO.

[0293] The switch SW21 has a first terminal electrically connected to the node N21, a second terminal electrically connected to the conductive film S1g(j), and a gate electrode having the function of controlling the conductive state or non-conductive state based on the potential of the conductive film G1(i).

[0294] The switch SW22 includes a first terminal electrically connected to the conductive film S2g(j) and a gate electrode having a function of controlling the conductive state or non-conductive state based on the potential of the conductive film G2(i).

[0295] The capacitor C21 includes a conductive film electrically connected to the node N21 and a conductive film electrically connected to the second electrode of the switch SW22.

[0296] This allows an image signal to be stored in node N21. Alternatively, the potential of node N21 can be changed using switch SW22. Alternatively, the intensity of light emitted by light-emitting device 550G(i, j) can be controlled using the potential of node N21.

[0297] <<Structure Example of Transistor M21>> A bottom-gate transistor, a top-gate transistor, or the like can be used for the functional layer 520. Specifically, the transistor can be used as a switch.

[0298] The transistor includes a semiconductor film 508, a conductive film 504, a conductive film 512A, and a conductive film 512B (see FIG. 4B). The transistor is formed over, for example, the insulating film 501C.

[0299] The semiconductor film 508 includes a region 508A electrically connected to the conductive film 512A and a region 508B electrically connected to the conductive film 512B. The semiconductor film 508 includes a region 508C between the region 508A and the region 508B.

[0300] The conductive film 504 has a region overlapping with the region 508C, and the conductive film 504 functions as a gate electrode.

[0301] The insulating film 506 has a region sandwiched between the semiconductor film 508 and the conductive film 504. The insulating film 506 functions as a gate insulating film.

[0302] The conductive film 512A has a function as either a source electrode or a drain electrode, and the conductive film 512B has the other function as either a source electrode or a drain electrode.

[0303] The conductive film 524 can also be used for a transistor. The conductive film 524 has a region where the semiconductor film 508 is sandwiched between the conductive film 524 and the conductive film 504. The conductive film 524 functions as a second gate electrode. The insulating film 501D is sandwiched between the semiconductor film 508 and the conductive film 524 and functions as a second gate insulating film.

[0304] Note that a semiconductor film to be used for a transistor in a pixel circuit can be formed in the same process as a semiconductor film to be used for a transistor in a driver circuit. For example, a semiconductor film having the same composition as that of a semiconductor film to be used for a transistor in a pixel circuit can be used for the driver circuit.

[0305] <<Structure Example 1 of Semiconductor Film 508>> For example, a semiconductor containing a Group 14 element can be used for the semiconductor film 508. Specifically, a semiconductor containing silicon can be used for the semiconductor film 508.

[0306] [Hydrogenated Amorphous Silicon] For example, hydrogenated amorphous silicon can be used for the semiconductor film 508. Alternatively, microcrystalline silicon or the like can be used for the semiconductor film 508. This makes it possible to provide a functional panel with less display unevenness than, for example, a functional panel using polysilicon for the semiconductor film 508. Alternatively, it is easy to increase the size of the functional panel.

[0307] [Polysilicon] For example, polysilicon can be used for the semiconductor film 508. This allows the field-effect mobility of the transistor to be higher than that of a transistor using hydrogenated amorphous silicon for the semiconductor film 508. Alternatively, the driving capability can be improved compared to that of a transistor using hydrogenated amorphous silicon for the semiconductor film 508. Alternatively, the aperture ratio of a pixel can be improved compared to that of a transistor using hydrogenated amorphous silicon for the semiconductor film 508.

[0308] Alternatively, the reliability of the transistor can be improved compared to a transistor using hydrogenated amorphous silicon for the semiconductor film 508, for example.

[0309] Alternatively, the temperature required to manufacture the transistor can be lower than that of a transistor using single crystal silicon, for example.

[0310] Alternatively, a semiconductor film used for a transistor in a driver circuit can be formed in the same process as a semiconductor film used for a transistor in a pixel circuit. Alternatively, the driver circuit can be formed over the same substrate as the substrate on which the pixel circuit is formed. Alternatively, the number of components constituting an electronic device can be reduced.

[0311] [Single Crystal Silicon] For example, single crystal silicon can be used for the semiconductor film 508. This allows for higher definition than, for example, a functional panel using hydrogenated amorphous silicon for the semiconductor film 508. Alternatively, for example, a functional panel with less display unevenness can be provided than, for example, a functional panel using polysilicon for the semiconductor film 508. Alternatively, for example, smart glasses or a head-mounted display can be provided.

[0312] <<Configuration Example 2 of Semiconductor Film 508>> For example, a metal oxide can be used for the semiconductor film 508. This allows the pixel circuit to hold an image signal for a longer period of time compared to a pixel circuit that uses a transistor using silicon for the semiconductor film. Specifically, a selection signal can be supplied at a frequency of less than 30 Hz, preferably less than 1 Hz, and more preferably less than once per minute while suppressing the occurrence of flicker. As a result, fatigue accumulated in a user of an information processing device can be reduced. Furthermore, power consumption associated with driving can be reduced.

[0313] For example, a transistor including an oxide semiconductor can be used. Specifically, an oxide semiconductor containing indium, an oxide semiconductor containing indium, gallium, and zinc, or an oxide semiconductor containing indium, gallium, zinc, and tin can be used for the semiconductor film.

[0314] For example, a transistor having a smaller leakage current in an off state than a transistor using silicon for a semiconductor film can be used. Specifically, a transistor using an oxide semiconductor for a semiconductor film can be used as a switch or the like. This allows the potential of a floating node to be held for a longer time than a circuit using a silicon transistor for a switch.

[0315] <<Structure Example 3 of the Semiconductor Film 508>> For example, a compound semiconductor can be used as a semiconductor for the transistor. Specifically, a semiconductor containing gallium arsenide can be used.

[0316] For example, an organic semiconductor can be used as a semiconductor for a transistor. Specifically, an organic semiconductor containing polyacenes or graphene can be used for a semiconductor film.

[0317] <Configuration Example 1 of Light-Emitting Device 550G(i,j)> The light-emitting device 550G(i,j) is electrically connected to the pixel circuit 530G(i,j) (see FIG. 3). The light-emitting device 550G(i,j) operates based on the potential of the node N21.

[0318] The light-emitting device 550G(i,j) includes an electrode 551G(i,j) and an electrode 552G(i,j). The electrode 551G(i,j) is electrically connected to the pixel circuit 530G(i,j), and the electrode 552G(i,j) is electrically connected to the conductive film VCOM2.

[0319] For example, an organic electroluminescent element, an inorganic electroluminescent element, a light-emitting diode, a QDLED (Quantum Dot LED), or the like can be used for the light-emitting device 550G(i, j).

[0320] <Configuration Example 4 of Display Device 700> A display device 700 described in this embodiment includes a pair of pixels 703(i, j) (see FIG. 5A).

[0321] <<Configuration Example of a Set of Pixels 703(i,j)>> A set of pixels 703(i,j) includes a pixel 702G(i,j), a pixel 702B(i,j), and a pixel 702R(i,j).

[0322] Pixel 702G(i,j) comprises light-emitting device 550G(i,j), pixel 702B(i,j) comprises light-emitting device 550B(i,j), and pixel 702R(i,j) comprises light-emitting device 550R(i,j).

[0323] For example, the light emitting devices can be arranged at a pitch of 2.8 μm along the cutting line X1-X2. The light emitting devices can be arranged at a pitch of 8.4 μm along the cutting line Y3-Y4. A gap of 0.55 μm can be provided between the light emitting devices. This increases the resolution of the display device. The aperture ratio can also be increased.

[0324] <<Configuration Example 2 of Light-Emitting Device 550G(i,j)>> Light-emitting device 550G(i,j) includes electrode 551G(i,j), electrode 552G(i,j), unit 103G(i,j), unit 103G2(i,j), intermediate layer 106G(i,j), layer 105G2(i,j), and layer 104G(i,j) (see FIG. 5B ).

[0325] The conductive film 552 includes an electrode 552G(i, j), and is electrically connected to the conductive film VCOM2.

[0326] Configuration Example 1 of Light-Emitting Device 550B(i,j) The light-emitting device 550B(i,j) includes an insulating film 573 between it and the light-emitting device 550G(i,j) (see FIG. 5C).

[0327] <Structure Example 1 of the Insulating Film 573> For example, the insulating film 573 can be formed using an insulating inorganic material, an insulating organic material, or an insulating composite material containing an inorganic material and an organic material.

[0328] Specifically, the insulating film 573 can be formed using an inorganic oxide film, an inorganic nitride film, an inorganic oxynitride film, or the like, or a stacked material formed by stacking a plurality of films selected from these.

[0329] For example, a film containing a silicon oxide film, a silicon nitride film, a silicon oxynitride film, an aluminum oxide film, or the like, or a film containing a stacked material selected from these films can be used for the insulating film 573. Note that a silicon nitride film is a dense film and has an excellent function of suppressing diffusion of impurities.

[0330] For example, the insulating film 573 can be made of polyester, polyolefin, polyamide, polyimide, polycarbonate, polysiloxane, acrylic resin, or the like, or a laminated material or composite material of a plurality of resins selected from these.

[0331] <<Structure Example 2 of the Insulating Film 573>> The insulating film 573 includes an insulating film 573(1) and an insulating film 573(2).

[0332] For example, an insulating inorganic material can be used for the insulating film 573(1). Specifically, aluminum oxide can be used for the insulating film 573(1). For example, a dense film formed by a chemical vapor deposition method, an atomic layer deposition (ALD) method, or the like can be used for the insulating film 573(1).

[0333] For example, an insulating organic material can be used for the insulating film 573(2). Specifically, polyimide or acrylic resin can be used for the insulating film 573(2). Furthermore, a photosensitive material can be used for the insulating film 573(2).

[0334] <<Configuration Example 1 of Light-Emitting Device 550R(i,j)>> Furthermore, the light-emitting device 550R(i,j) includes an insulating film 573 between it and the light-emitting device 550G(i,j).

[0335] <Configuration Example 5 of Display Device 700> The display device 700 includes a light-emitting device 550G(i,j) and a light-emitting device 550B(i,j) (see FIGS. 5C and 6). The display device 700 also includes a light-emitting device 550R(i,j).

[0336] <<Configuration Example 3 of Light-Emitting Device 550G(i,j)>> The light-emitting device 550G(i,j) includes an electrode 551G(i,j), an electrode 552G(i,j), a unit 103G(i,j), a unit 103G2(i,j), an intermediate layer 106G(i,j), and a layer 105G2(i,j). Note that the unit 103G(i,j) and the unit 103G2(i,j) are configured to emit light of a green hue.

[0337] For example, the configuration of light-emitting device 550X(i,j) described in embodiment 1 can be applied to light-emitting device 550G(i,j). Specifically, the "X" in the symbols used in the description of light-emitting device 550X(i,j) can be replaced with "G" and used in the description of light-emitting device 550G(i,j).

[0338] <<Configuration Example 2 of Light-Emitting Device 550B(i,j)>> The light-emitting device 550B(i,j) includes an electrode 551B(i,j), an electrode 552B(i,j), a unit 103B(i,j), a unit 103B2(i,j), an intermediate layer 106B(i,j), and a layer 105B2(i,j). Note that the unit 103B(i,j) and the unit 103B2(i,j) are configured to emit light of a blue hue.

[0339] For example, the configuration of light-emitting device 550X(i,j) described in embodiment 1 can be applied to light-emitting device 550B(i,j). Specifically, the "X" in the symbols used in the description of light-emitting device 550X(i,j) can be replaced with "B" and used in the description of light-emitting device 550B(i,j).

[0340] <<Configuration Example 2 of Light-Emitting Device 550R(i,j)>> The light-emitting device 550R(i,j) includes an electrode 551R(i,j), an electrode 552R(i,j), a unit 103R(i,j), a unit 103R2(i,j), an intermediate layer 106R(i,j), and a layer 105R2(i,j). Note that the unit 103R(i,j) and the unit 103R2(i,j) are configured to emit light of a red hue.

[0341] For example, the configuration of light-emitting device 550X(i,j) described in embodiment 1 can be applied to light-emitting device 550R(i,j). Specifically, the "X" in the symbols used in the description of light-emitting device 550X(i,j) can be replaced with "R" and used in the description of light-emitting device 550R(i,j).

[0342] <<Configuration Example of Intermediate Layer 106G(i,j), Intermediate Layer 106B(i,j), and Intermediate Layer 106R(i,j)>> Intermediate layer 106B(i,j) has a gap 106GB(i,j) between it and intermediate layer 106G(i,j) (see FIG. 6 ). This makes it possible to suppress current flowing between intermediate layer 106G(i,j) and intermediate layer 106B(i,j). It also makes it possible to suppress crosstalk between light-emitting device 550G(i,j) and light-emitting device 550B(i,j).

[0343] Furthermore, the intermediate layer 106R(i,j) has a gap 106RG(i,j) between it and the intermediate layer 106G(i,j). This makes it possible to suppress current flowing between the intermediate layer 106R(i,j) and the intermediate layer 106G(i,j). This makes it possible to suppress the occurrence of crosstalk between the light-emitting device 550R(i,j) and the light-emitting device 550G(i,j).

[0344] <<Configuration example of layer 105G2(i,j), layer 105B2(i,j), layer 105R2(i,j)>> Layer 105B2(i,j) has a gap 105GB2(i,j) between it and layer 105G2(i,j) (see Figure 6).

[0345] Furthermore, the layer 105R2(i,j) has a gap 105RG2(i,j) between it and the layer 105G2(i,j).

[0346] <<Configuration Example of Layer 104G(i,j), Layer 104B(i,j), and Layer 104R(i,j)>> Layer 104B(i,j) has a gap 104GB(i,j) between it and layer 104G(i,j) (see FIG. 6 ). This can suppress current flow between layer 104G(i,j) and layer 104B(i,j). It can also suppress crosstalk between light-emitting device 550G(i,j) and light-emitting device 550B(i,j).

[0347] Furthermore, the layer 104R(i,j) has a gap 104RG(i,j) between it and the layer 104G(i,j). This makes it possible to suppress current flowing between the layer 104R(i,j) and the layer 104G(i,j). It also makes it possible to suppress the occurrence of crosstalk between the light-emitting device 550R(i,j) and the light-emitting device 550G(i,j).

[0348] Note that this embodiment mode can be appropriately combined with other embodiment modes described in this specification.

[0349] Embodiment 3 In this embodiment, a display device and a display system which are one embodiment of the present invention will be described with reference to FIGS.

[0350] FIG. 7 is a block diagram illustrating a structure of a display device according to one embodiment of the present invention.

[0351] FIG. 8 is a block diagram illustrating the configuration of the display unit shown in FIG.

[0352] FIG. 9 is a block diagram illustrating a structure of a display device according to one embodiment of the present invention.

[0353] FIG. 10 is a block diagram illustrating the configuration of the pixel shown in FIG.

[0354] FIG. 11 is a block diagram illustrating a structure of a display device according to one embodiment of the present invention.

[0355] FIG. 12A is a flowchart relating to the correction method, and FIG. 12B is a schematic diagram illustrating the correction method.

[0356] 7 shows a block diagram for explaining each component included in the display device 10. The display device includes a driver circuit 40, a functional circuit 50, and a display unit 60.

[0357] <<Configuration Example 1 of Drive Circuit 40>> The drive circuit 40 includes, as an example, a gate driver 41 and a source driver 42. The gate driver 41 has a function of driving a plurality of gate lines GL for outputting signals to the pixel circuits 62R, 62G, and 62B. The source driver 42 has a function of driving a plurality of source lines SL for outputting signals to the pixel circuits 62R, 62G, and 62B. The drive circuit 40 also supplies voltages for displaying images in the pixel circuits 62R, 62G, and 62B to the pixel circuits 62R, 62G, and 62B via a plurality of wirings.

[0358] <<Configuration Example 1 of Functional Circuit 50>> The functional circuit 50 has a CPU 51, which can be used for arithmetic processing of data. The CPU 51 also has a CPU core 53. The CPU core 53 has a flip-flop 80 for temporarily holding data used for the arithmetic processing. The flip-flop 80 has a plurality of scan flip-flops 81, and each scan flip-flop 81 is electrically connected to a backup circuit 82 provided in the display unit 60. The flip-flop 80 inputs and outputs data of the scan flip-flops (backup data) to and from the backup circuit 82.

[0359] <Display Unit 60> With reference to FIGS. 7 and 8, a configuration example of the arrangement of the backup circuit 82 and the pixel circuits 62R, 62G, and 62B, which are sub-pixels, in the display unit 60 will be described.

[0360] 8 illustrates a display unit 60 in which a plurality of pixels 61 are arranged in a matrix. Each pixel 61 includes pixel circuits 62R, 62G, and 62B as well as a backup circuit 82. As described above, the backup circuit 82 and the pixel circuits 62R, 62G, and 62B can all be formed using OS transistors and therefore can be arranged within the same pixel.

[0361] The display unit 60 has a plurality of pixels 61, each of which is provided with pixel circuits 62R, 62G, and 62B, and a backup circuit 82. As described in Fig. 8, the backup circuit 82 does not necessarily have to be arranged within the pixel 61, which is the repeating unit. The backup circuit 82 can be arranged freely depending on the shape of the display unit 60, the shapes of the pixel circuits 62R, 62G, and 62B, etc.

[0362] 9 is a block diagram schematically illustrating a structural example of a display device 10 that is a display device of one embodiment of the present invention. The display device 10 includes a layer 20 and a layer 30. The layer 30 can be stacked, for example, above the layer 20. An interlayer insulator or a conductor for electrical connection between different layers can be provided between the layer 20 and the layer 30.

[0363] <<Layer 20>> The transistors provided in the layer 20 can be, for example, transistors having silicon in their channel formation regions (also referred to as Si transistors), such as transistors having single crystal silicon in their channel formation regions. In particular, when a transistor having single crystal silicon in its channel formation region is used as the transistor provided in the layer 20, the on-state current of the transistor can be increased. Therefore, it is preferable because the circuit included in the layer 20 can be driven at high speed. In addition, Si transistors can be formed by microfabrication to have a channel length of 3 nm to 10 nm, and therefore the display device 10 can be provided with an accelerator such as a CPU or a GPU, an application processor, or the like.

[0364] The layer 20 is provided with a driving circuit 40 and a functional circuit 50. The Si transistors in the layer 20 can increase the on-current of the transistors, so that each circuit can be driven at high speed.

[0365] <<Configuration Example 2 of the Drive Circuit 40>> The drive circuit 40 includes a gate line drive circuit, a source line drive circuit, and the like for driving the pixel circuits 62R, 62G, and 62B. As an example, the drive circuit 40 includes a gate line drive circuit and a source line drive circuit for driving the pixels 61 of the display unit 60. By arranging the drive circuit 40 in a layer 20 different from the layer 30 on which the display is provided, the area occupied by the display unit in the layer 30 can be increased. The drive circuit 40 may also include an LVDS (Low Voltage Differential Signaling) circuit or a D / A (Digital to Analog) conversion circuit, which functions as an interface for receiving data such as image data from outside the display device 10. The Si transistors in the layer 20 can increase their on-state current. The channel length or channel width of the Si transistors may be varied depending on the operating speed of each circuit.

[0366] <<Layer 30>> The transistor provided in the layer 30 can be, for example, an OS transistor. In particular, it is preferable to use a transistor including an oxide containing at least one of indium, an element M (the element M is aluminum, gallium, yttrium, or tin), and zinc in a channel formation region as the OS transistor. Such an OS transistor has a characteristic of having a very low off-state current. Therefore, it is preferable to use an OS transistor as a transistor provided in a pixel circuit in a display portion, because analog data written to the pixel circuit can be retained for a long period of time.

[0367] The layer 30 includes a display unit 60 having a plurality of pixels 61. Each pixel 61 includes pixel circuits 62R, 62G, and 62B that control red, green, and blue light emission. The pixel circuits 62R, 62G, and 62B function as subpixels of the pixel 61. The pixel circuits 62R, 62G, and 62B each include an OS transistor, allowing analog data written to the pixel circuit to be retained for a long period of time. Each pixel 61 in the layer 30 is also provided with a backup circuit 82. The backup circuit may also be referred to as a storage circuit or a memory circuit. The backup circuit also inputs and outputs data (backup data BD) from the scan flip-flop to and from the flip-flop 80.

[0368] 10A and 10B show a configuration example of a pixel circuit 62 applicable to the pixel circuits 62R, 62G, and 62B, and a light-emitting element 70 connected to the pixel circuit 62. Fig. 10A is a diagram showing the connection of each element, and Fig. 10B is a diagram schematically showing the hierarchical relationship between the drive circuit 40, pixel circuit 62, and light-emitting element 70.

[0369] In this specification and the like, the term “element” may be replaced with “device” in some cases. For example, a display element, a light-emitting element, and a liquid crystal element may be replaced with a display device, a light-emitting device, and a liquid crystal device, for example.

[0370] 10A and 10B includes a switch SW21, a switch SW22, a transistor M21, and a capacitor C21. The switch SW21, the switch SW22, and the transistor M21 can be OS transistors. Each of the OS transistors SW21, SW22, and M21 preferably includes a back gate electrode. In this case, the back gate electrode may be configured to receive the same signal as the gate electrode, or a signal different from the gate electrode may be applied to the back gate electrode.

[0371] The transistor M21 includes a gate electrode electrically connected to the switch SW21, a first electrode electrically connected to the light-emitting element 70, and a second electrode electrically connected to the conductive film ANO. The conductive film ANO is a wiring for applying a potential for supplying a current to the light-emitting element 70.

[0372] The switch SW21 has a first terminal electrically connected to the gate electrode of the transistor M21, a second terminal electrically connected to the source line SL, and a gate electrode having the function of controlling the conductive state or non-conductive state based on the potential of the gate line GL1.

[0373] The switch SW22 includes a first terminal electrically connected to the wiring V0, a ​​second terminal electrically connected to the light-emitting element 70, and a gate electrode having a function of controlling a conductive state or a non-conductive state based on the potential of the gate line GL2. The wiring V0 is a wiring for applying a reference potential and a wiring for outputting a current flowing through the pixel circuit 62 to the drive circuit 40 or the functional circuit 50.

[0374] The capacitor C21 includes a conductive film electrically connected to the gate electrode of the transistor M21 and a conductive film electrically connected to the second electrode of the switch SW22.

[0375] The light-emitting element 70 includes a first electrode electrically connected to the first electrode of the transistor M21 and a second electrode electrically connected to a conductive film VCOM. The conductive film VCOM is a wiring for applying a potential for supplying a current to the light-emitting element 70.

[0376] This allows the intensity of light emitted by the light-emitting element 70 to be controlled in accordance with an image signal applied to the gate electrode of the transistor M21. Furthermore, the amount of current flowing through the light-emitting element 70 can be increased by applying a reference potential to the wiring V0 via the switch SW22. Furthermore, by monitoring the amount of current flowing through the wiring V0 with an external circuit, the amount of current flowing through the light-emitting element can be estimated. This allows pixel defects and the like to be detected.

[0377] <Pixel Circuit Configuration Example 2> In the configuration shown in FIG. 10B as an example, the wiring electrically connecting the pixel circuit 62 and the drive circuit 40 can be shortened, thereby reducing the wiring resistance of the wiring. This allows data to be written at high speed, thereby enabling the display device 10 to be driven at high speed. This allows the display device 10 to have a large number of pixels 61, ensuring a sufficient frame period, thereby increasing the pixel density of the display device 10. Furthermore, increasing the pixel density of the display device 10 can increase the resolution of images displayed by the display device 10. For example, the pixel density of the display device 10 can be 1000 ppi or more, 5000 ppi or more, or 7000 ppi or more. Therefore, the display device 10 can be used as a display device for AR or VR, for example, and is suitable for use in electronic devices such as HMDs, where the display unit is close to the user.

[0378] 10B illustrates a diagram in which the gate line GL1, the gate line GL2, the conductive film VCOM, the wiring V0, the conductive film ANO, and the source line SL are supplied via wiring from the driver circuit 40 below the pixel circuit 62, but one embodiment of the present invention is not limited to this. For example, wiring for supplying signals and voltages from the driver circuit 40 may be routed to the periphery of the display portion 60 and electrically connected to each pixel circuit 62 arranged in a matrix on the layer 30. In this case, it is effective to provide the gate driver 41 included in the driver circuit 40 on the layer 30. That is, it is effective to use OS transistors as the transistors of the gate driver 41. It is effective to provide part of the function of the source driver 42 included in the driver circuit 40 on the layer 30. For example, it is effective to provide a demultiplexer in the layer 30 that distributes signals output from the source driver 42 to each source line. It is effective to use OS transistors as the transistors of the demultiplexer.

[0379] <Backup Circuit 82> The backup circuit 82 is preferably a memory including an OS transistor, for example. A backup circuit including an OS transistor has advantages such as being able to suppress a voltage drop corresponding to the data to be backed up and consuming almost no power to retain the data, due to the feature of the OS transistor that the off-state current is extremely small. The backup circuit 82 including an OS transistor can be provided in the display unit 60 in which a plurality of pixels 61 are arranged. FIG. 9 illustrates a state in which the backup circuit 82 is provided for each pixel 61.

[0380] The backup circuit 82 formed of an OS transistor can be stacked with the layer 20 having a Si transistor. The backup circuit 82 may be arranged in a matrix similar to the subpixels in the pixel 61, or may be arranged for each of a plurality of pixels. That is, the backup circuit 82 can be arranged in the layer 30 without being restricted by the arrangement of the pixels 61. This increases the degree of freedom in the layout of the display unit / circuit, and allows the backup circuit 82 to be arranged without increasing the circuit area, thereby increasing the storage capacity of the backup circuit 82 required for arithmetic processing.

[0381] <Configuration Example 3 of Display Device> FIG. 11 shows a modified example of each configuration of the display device 10 described above.

[0382] The block diagram of the display device 10A shown in FIG. 11 corresponds to a configuration in which an accelerator 52 is added to the functional circuit 50 in the display device 10 of FIG.

[0383] The accelerator 52 functions as a dedicated arithmetic circuit for the product-sum operation of the artificial neural network NN. The operation using the accelerator 52 can perform processes such as up-converting display data to correct the contours of an image. While the accelerator 52 is performing the operation, the CPU 51 can be configured to be power-gated to reduce power consumption.

[0384] <Configuration Example of Display System> In addition, in a display device according to one embodiment of the present invention, pixel circuits and functional circuits can be stacked, and therefore defective pixels can be detected using the functional circuits provided below the screen circuits. By using information about the defective pixels, display defects due to the defective pixels can be corrected, and normal display can be achieved.

[0385] A part of the correction method exemplified below may be executed by a circuit provided outside the display device, or may be executed by the functional circuit 50 of the display device 10.

[0386] A more specific example of the correction method will be described below: Fig. 12A is a flowchart showing the correction method described below.

[0387] First, in step S1, the correction operation is started.

[0388] Next, in step S2, the pixel current is read out. For example, each pixel can be driven to output a current to a monitor line electrically connected to the pixel.

[0389] Next, in step S3, the read current is converted into a voltage. At this time, if a digital signal is to be handled in subsequent processing, the voltage can be converted into digital data in step S3. For example, analog data can be converted into digital data by using an analog-to-digital converter (ADC).

[0390] Next, in step S4, pixel parameters for each pixel are obtained based on the obtained data, such as the threshold voltage or field effect mobility of the driving transistor, the threshold voltage of the light-emitting element, and the current value at a predetermined voltage.

[0391] Next, in step S5, each pixel is judged to be abnormal based on the pixel parameter. For example, if the value of the pixel parameter exceeds (or falls below) a predetermined threshold value, the pixel is recognized as an abnormal pixel.

[0392] The abnormal pixels include dark spot defects with significantly low brightness relative to the input data potential, and bright spot defects with significantly high brightness.

[0393] In step S5, the address of the abnormal pixel and the type of defect can be identified and acquired.

[0394] Subsequently, in step S6, a correction process is performed.

[0395] An example of the correction process will be described with reference to Fig. 12B. Fig. 12B schematically shows 3 x 3 pixels. Here, the central pixel is assumed to be pixel 61D, which is a dark point defect. Fig. 12B schematically shows a state in which pixel 61D is turned off and the surrounding pixels 61N are turned on at a predetermined brightness.

[0396] A dark point defect is a defect in which the brightness of the pixel is unlikely to reach normal brightness even if a correction is made to increase the data potential input to the pixel. Therefore, as shown in Figure 12B, a correction is made to increase the brightness of pixel 61N surrounding pixel 61D, which is a dark point defect. This makes it possible to display a normal image even if a dark point defect occurs.

[0397] In the case of a bright spot defect, the bright spot defect can be made less noticeable by lowering the brightness of the surrounding pixels.

[0398] In particular, in the case of high-resolution display devices (e.g., 1000 ppi or more), it is difficult to visually recognize each pixel separately, so it is particularly effective to use a correction method that compensates for abnormal pixels using surrounding pixels.

[0399] On the other hand, it is preferable to correct the defective pixels such as dark spots and bright spots so that no data potential is input.

[0400] In this way, correction parameters can be set for each pixel. By applying the correction parameters to input image data, corrected image data can be generated to display an optimal image on the display device 10.

[0401] Furthermore, since variations exist in pixel parameters not only for abnormal pixels and pixels surrounding the abnormal pixels but also for pixels not determined to be abnormal pixels, unevenness due to the variations may be visible when an image is displayed. Therefore, for pixels not determined to be abnormal pixels, correction parameters can be set to cancel (level out) the variations in pixel parameters. For example, a reference value based on the median or average value of pixel parameters for some or all pixels can be set, and a correction value for canceling the difference between the pixel parameters of a specific pixel and the reference value can be set as the correction parameter for that pixel.

[0402] Furthermore, for pixels surrounding an abnormal pixel, it is preferable to set correction data that takes into consideration both the amount of correction for compensating for the abnormal pixel and the amount of correction for canceling variations in pixel parameters.

[0403] Then, in step S7, the correction operation is completed.

[0404] Thereafter, an image can be displayed based on the correction parameters obtained in the above correction operation and the input image data.

[0405] A neural network may be used as one of the correction operations. When performing calculations based on an artificial neural network in the above-described display correction system, the system is configured to repeatedly perform product-sum operations. Calculations using the accelerator 52 can correct the above-described display defects. Power gating control of the CPU 51 can be configured to reduce power consumption during calculations performed by the accelerator 52. For example, the neural network can determine correction parameters based on inference results obtained by machine learning. For example, the correction parameters can be estimated by performing calculations based on artificial neural networks such as deep neural networks (DNNs), convolutional neural networks (CNNs), recurrent neural networks (RNNs), autoencoders, deep Boltzmann machines (DBMs), and deep belief networks (DBNs). When determining correction parameters using a neural network, high-precision correction can be performed to prevent abnormal pixels from becoming noticeable, even without using detailed correction algorithms.

[0406] The above is the explanation of the correction method.

[0407] The calculations performed by the display correction system to correct the current flowing through the pixels can be performed by the CPU 51, which can continuously store data during the calculation as backup data. This is particularly effective when performing computations that require a huge amount of calculations, such as calculations based on artificial neural networks. By making the CPU 51 function as an application processor, it is possible to reduce display defects and power consumption by combining it with a drive that allows the frame frequency to be varied.

[0408] This embodiment mode can be combined with the descriptions of other embodiment modes as appropriate.

[0409] Embodiment 4 In this embodiment, an example of a cross-sectional structure of a display device 10 which is one embodiment of the present invention will be described.

[0410] <Configuration Example 1 of Display Device> FIG. 13 is a cross-sectional view showing a configuration example of a display device 10. The display device 10 includes an insulator 421 and a base material 770, and the insulator 421 and the base material 770 are attached to each other with a sealant 712. An OS transistor is preferably used for a pixel circuit. At least a part of a driver circuit may be formed using an OS transistor. At least a part of a functional circuit may be formed using an OS transistor. At least a part of a driver circuit may be externally provided. At least a part of a functional circuit may be externally provided.

[0411] <Insulator 421, Insulator 214, and Insulator 216> Any of various insulator substrates such as a glass substrate or a sapphire substrate can be used as the insulator 421. The insulator 214 is provided over the insulator 421, and the insulator 216 is provided over the insulator 214.

[0412] <<Insulator 222, Insulator 224, Insulator 254, Insulator 280, Insulator 274, Insulator 281>> Over the insulator 216, the insulator 222, the insulator 224, the insulator 254, the insulator 280, the insulator 274, and the insulator 281 are provided.

[0413] The insulators 421, 214, 280, 274, and 281 function as interlayer films and may also function as planarization films that cover the uneven shapes below them.

[0414] <<Insulator 361>> The insulator 361 is provided on the insulator 281. The conductor 317 and the conductor 337 are embedded in the insulator 361. Here, the height of the top surface of the conductor 337 and the height of the top surface of the insulator 361 can be made approximately the same.

[0415] <<Insulator 363>> The insulator 363 is provided on the conductor 337 and the insulator 361. The conductors 347, 353, 355, and 357 are embedded in the insulator 363. Here, the height of the top surfaces of the conductors 353, 355, and 357 can be made approximately the same as the height of the top surface of the insulator 363.

[0416] The conductors 341, 343, and 351 are embedded in the insulator 363. Here, the height of the top surface of the conductor 351 and the height of the top surface of the insulator 363 can be made to be approximately the same.

[0417] The insulators 361 and 363 function as interlayer films and may also function as planarizing films that cover uneven shapes below them. For example, the top surface of the insulator 363 may be planarized by planarization treatment using a chemical mechanical polishing (CMP) method or the like to improve the planarity.

[0418] <<Connection Electrode 760>> A connection electrode 760 is provided on the conductor 353, the conductor 355, the conductor 357, and the insulator 363. An anisotropic conductor 780 is provided so as to be electrically connected to the connection electrode 760, and an FPC (Flexible Printed Circuit) 716 is provided so as to be electrically connected to the anisotropic conductor 780. Various signals and the like are supplied to the display device 10 from outside the display device 10 via the FPC 716.

[0419] 13 shows three conductors, namely, the conductor 353, the conductor 355, and the conductor 357, as conductors having a function of electrically connecting the connection electrode 760 and the conductor 347; however, one embodiment of the present invention is not limited to this. The number of conductors having a function of electrically connecting the connection electrode 760 and the conductor 347 may be one, two, or four or more. By providing a plurality of conductors having a function of electrically connecting the connection electrode 760 and the conductor 347, contact resistance can be reduced.

[0420] <<Transistor 750>> A transistor 750 is provided over the insulator 214. The transistor 750 can be the transistor provided in the layer 30 described in Embodiment 3. For example, the transistor 750 can be a transistor provided in the pixel circuit 62. An OS transistor can be suitably used as the transistor 750. An OS transistor has an extremely low off-state current. Therefore, the retention time of image data and the like can be extended, thereby reducing the frequency of a refresh operation. Therefore, the power consumption of the display device 10 can be reduced.

[0421] The transistor 750 can be provided in the backup circuit 82. An OS transistor can be preferably used as the transistor 750. An OS transistor has an extremely low off-state current. Therefore, data stored in the flip-flop can be retained even during a period when the shared power supply voltage is stopped. This allows the CPU to operate normally (intermittently stop the power supply voltage). Therefore, the power consumption of the display device 10 can be reduced.

[0422] Conductors 301a and 301b are embedded in the insulators 254, 280, 274, and 281. The conductor 301a is electrically connected to one of the source and the drain of the transistor 750, and the conductor 301b is electrically connected to the other of the source and the drain of the transistor 750. Here, the height of the top surfaces of the conductors 301a and 301b can be made approximately the same as the height of the top surface of the insulator 281.

[0423] The conductors 311, 313, 331, a capacitor 790, a conductor 333, and a conductor 335 are embedded in the insulator 361. The conductors 311 and 313 are electrically connected to the transistor 750 and function as wirings. The conductors 333 and 335 are electrically connected to the capacitor 790. Here, the height of the top surfaces of the conductors 331, 333, and 335 can be made approximately the same as the height of the top surface of the insulator 361.

[0424] 13 , the capacitor 790 has a lower electrode 321 and an upper electrode 325. An insulator 323 is provided between the lower electrode 321 and the upper electrode 325. That is, the capacitor 790 has a layered structure in which the insulator 323, which functions as a dielectric, is sandwiched between a pair of electrodes. Note that while FIG. 13 shows an example in which the capacitor 790 is provided on the insulator 281, the capacitor 790 may be provided on an insulator different from the insulator 281.

[0425] FIG. 13 shows an example in which conductors 301a, 301b, and 305 are formed in the same layer. It also shows an example in which conductors 311, 313, 317, and a lower electrode 321 are formed in the same layer. It also shows an example in which conductors 331, 333, 335, and 337 are formed in the same layer. It also shows an example in which conductors 341, 343, and 347 are formed in the same layer. It also shows an example in which conductors 351, 353, 355, and 357 are formed in the same layer. Forming multiple conductors in the same layer can simplify the manufacturing process of the display device 10, thereby reducing the manufacturing cost of the display device 10. These conductors may be formed in different layers and may contain different types of materials.

[0426] 13 includes a light-emitting element 70. The light-emitting element 70 includes a conductor 772, an EL layer 786, and a conductor 788. The EL layer 786 includes an organic compound or an inorganic compound such as quantum dots.

[0427] Materials that can be used for the organic compounds include fluorescent materials and phosphorescent materials, while materials that can be used for the quantum dots include colloidal quantum dot materials, alloy quantum dot materials, core-shell quantum dot materials, and core quantum dot materials.

[0428] The luminance of the display device 10 is, for example, 500 cd / m ２ or more, preferably 1000 cd / m ２ More than 10000cd / m ２More preferably, 2000 cd / m or less ２ More than 5000cd / m ２ It can be as follows:

[0429] The conductor 772 is electrically connected to the other of the source and the drain of the transistor 750 through the conductors 351, 341, 331, 313, and 301b. The conductor 772 is formed over the insulator 363 and functions as a pixel electrode.

[0430] A material that is transparent to visible light or a material that is reflective to visible light can be used for the conductor 772. As a light-transmitting material, for example, an oxide material containing indium, zinc, tin, or the like can be used. As a reflective material, for example, a material containing aluminum, silver, or the like can be used.

[0431] The light-emitting element 70 can be a top-emission light-emitting element having a light-transmitting conductor 788. Note that the light-emitting element 70 may have a bottom-emission structure in which light is emitted to the conductor 772 side, or a dual-emission structure in which light is emitted to both the conductor 772 and the conductor 788.

[0432] The light-emitting element 70 may have a micro-optical resonator (microcavity) structure, which allows light of a predetermined color (e.g., RGB) to be extracted, enabling the display device 10 to display a high-brightness image. Furthermore, the power consumption of the display device 10 can be reduced.

[0433] <<Light-shielding layer 738, insulator 734>> A light-shielding layer 738 and an insulator 734 in contact with the light-shielding layer 738 are provided on the base material 770 side. The light-shielding layer 738 has a function of blocking light emitted from an adjacent region. Alternatively, the light-shielding layer 738 has a function of blocking external light from reaching the transistor 750 and the like.

[0434] 13, the insulator 730 is provided over the insulator 363. Here, the insulator 730 can be configured to cover part of the conductor 772. Note that although the structure in which the insulator 730 is provided is illustrated in this embodiment, the present invention is not limited to this. For example, a structure in which the insulator 730 is not provided may be used. Note that the case in which the insulator 730 is not provided is preferable because the opening of the display device can be increased.

[0435] The light-shielding layer 738 is provided to have a region overlapping with the insulator 730. The light-shielding layer 738 is covered with the insulator 734. The space between the light-emitting element 70 and the insulator 734 is filled with the sealing layer 732.

[0436] <<Structure 778>> The structure 778 is provided between the insulator 730 and the EL layer 786. The structure 778 is also provided between the insulator 730 and the insulator 734.

[0437] Although not shown in FIG. 13, the display device 10 can be provided with optical members (optical substrates) such as a polarizing member, a phase difference member, an anti-reflection member, and the like.

[0438] Furthermore, a colored layer can be provided. The colored layer is provided so as to have an area overlapping with the light-emitting element 70. By providing the colored layer, the color purity of the light extracted from the light-emitting element 70 can be increased. This allows the display device 10 to display a high-quality image. Furthermore, since, for example, all the light-emitting elements 70 of the display device 10 can be light-emitting elements that emit white light, it is not necessary to form the EL layer 786 by different colors, and the display device 10 can have high definition.

[0439] 14 is a cross-sectional view showing a configuration example of the display device 10. The display device 10 includes a substrate 701 and a base material 770, and the substrate 701 and the base material 770 are attached to each other with a sealing material 712. The display device 10 shown in FIG. 14 differs from the display device 10 shown in FIG. 13 in that it includes a transistor 601.

[0440] <<Substrate 701>> A single crystal semiconductor substrate such as a single crystal silicon substrate can be used as the substrate 701. Note that the substrate 701 may be a semiconductor substrate other than a single crystal semiconductor substrate.

[0441] A transistor 441 and a transistor 601 are provided over a substrate 701. The transistor 441 and the transistor 601 can be the transistors provided in the layer 20 described in Embodiment 3. For example, the transistors 441 and 601 can be used as transistors in the driver circuit 40 or the functional circuit 50 included in the layer 20.

[0442] The transistor 441 includes a conductor 443 that functions as a gate electrode, an insulator 445 that functions as a gate insulator, and a part of the substrate 701, and includes a semiconductor region 447 including a channel formation region, a low-resistance region 449 a that functions as one of a source region and a drain region, and a low-resistance region 449 b that functions as the other of the source region and the drain region. The transistor 441 may be either a p-channel type or an n-channel type.

[0443] The transistor 441 is electrically isolated from other transistors by an element isolation layer 403. Fig. 14 shows a case where the transistor 441 and the transistor 601 are electrically isolated by the element isolation layer 403. The element isolation layer 403 can be formed by a local oxidation of silicon (LOCOS) method, a shallow trench isolation (STI) method, or the like.

[0444] 14, a semiconductor region 447 has a convex shape. A conductor 443 is provided to cover the side surface and the top surface of the semiconductor region 447 with an insulator 445 interposed therebetween. Note that the conductor 443 covering the side surface of the semiconductor region 447 is not shown in FIG. A material that adjusts the work function can be used for the conductor 443.

[0445] A transistor having a convex semiconductor region such as the transistor 441 can be called a fin transistor because it utilizes the convex portion of a semiconductor substrate. Note that an insulator that is in contact with the upper portion of the convex portion and functions as a mask for forming the convex portion may be provided. Although FIG. 14 shows a structure in which the convex portion is formed by processing a part of the substrate 701, a semiconductor having a convex portion may be formed by processing an SOI substrate.

[0446] 14 is just an example, and the transistor 441 is not limited to this configuration and may have an appropriate configuration depending on the circuit configuration, the operation method of the circuit, etc. For example, the transistor 441 may be a planar transistor.

[0447] <<Transistor 601>> The transistor 601 can have a structure similar to that of the transistor 441.

[0448] <<Insulator 405, Insulator 407, Insulator 409, Insulator 411>> In addition to the element isolation layer 403, the transistor 441, and the transistor 601, the insulators 405, 407, 409, and 411 are provided over the substrate 701. A conductor 451 is embedded in the insulator 405, the insulator 407, the insulator 409, and the insulator 411. Here, the height of the top surface of the conductor 451 can be made approximately the same as the height of the top surface of the insulator 411.

[0449] The insulators 405, 407, 409, and 411 each function as an interlayer film and may also function as a planarization film that covers the uneven shapes below each of them.

[0450] <<Insulator 421, Insulator 214, Insulator 216>> The insulator 421 and the insulator 214 are provided over the conductor 451 and the insulator 411. The conductor 453 is embedded in the insulator 421 and the insulator 214. Here, the height of the top surface of the conductor 453 and the height of the top surface of the insulator 214 can be made approximately the same.

[0451] An insulator 216 is provided over the conductor 453 and the insulator 214. A conductor 455 is embedded in the insulator 216. Here, the height of the top surface of the conductor 455 and the height of the top surface of the insulator 216 can be made approximately the same.

[0452] <<Insulator 222, Insulator 224, Insulator 254, Insulator 280, Insulator 274, Insulator 281>> The insulators 222, 224, 254, 280, 274, and 281 are provided over the conductor 455 and the insulator 216.

[0453] Conductor 305 is embedded in insulator 222, insulator 224, insulator 254, insulator 280, insulator 274, and insulator 281. Here, the height of the top surface of conductor 305 and the height of the top surface of insulator 281 can be made approximately the same.

[0454] The insulators 421, 214, 280, 274, and 281 function as interlayer films and may also function as planarization films that cover the uneven shapes below them.

[0455] <<Insulator 361 >> The insulator 361 is provided over the conductor 305 and the insulator 281 .

[0456] <<Transistor 441>> As shown in Figure 14, the low-resistance region 449b, which functions as the other of the source region and the drain region of the transistor 441, is electrically connected to the FPC 716 via a conductor 451, a conductor 453, a conductor 455, a conductor 305, a conductor 317, a conductor 337, a conductor 347, a conductor 353, a conductor 355, a conductor 357, a connection electrode 760, and an anisotropic conductor 780.

[0457] 15 is a cross-sectional view illustrating a configuration example of a display device 10. The display device 10 includes a substrate 701 and a base material 770, and the substrate 701 and the base material 770 are attached to each other with a sealing material 712. The display device 10 illustrated in FIG. 15 differs from the display device 10 illustrated in FIG. 14 in that a transistor 750 has a structure similar to that of the transistor 441.

[0458] <<Substrate 701>> A single crystal semiconductor substrate such as a single crystal silicon substrate can be used as the substrate 701. Note that the substrate 701 may be a semiconductor substrate other than a single crystal semiconductor substrate.

[0459] A transistor 441 and a transistor 601 are provided over a substrate 701. The transistor 441 and the transistor 601 can be the transistors provided in the layer 20 described in Embodiment 3. For example, the transistors 441 and 601 can be used as transistors in the driver circuit 40 or the functional circuit 50 included in the layer 20.

[0460] The transistor 441 includes a conductor 443 that functions as a gate electrode, an insulator 445 that functions as a gate insulator, and a part of the substrate 701, and includes a semiconductor region 447 including a channel formation region, a low-resistance region 449 a that functions as one of a source region and a drain region, and a low-resistance region 449 b that functions as the other of the source region and the drain region. The transistor 441 may be either a p-channel type or an n-channel type.

[0461] The transistor 441 is electrically isolated from other transistors by an element isolation layer 403. Fig. 15 shows a case where the transistor 441 and the transistor 601 are electrically isolated by the element isolation layer 403. The element isolation layer 403 can be formed by a local oxidation of silicon (LOCOS) method, a shallow trench isolation (STI) method, or the like.

[0462] 15, a semiconductor region 447 has a convex shape. A conductor 443 is provided to cover the side surface and the top surface of the semiconductor region 447 with an insulator 445 interposed therebetween. Note that the conductor 443 covering the side surface of the semiconductor region 447 is not shown in FIG. A material that adjusts the work function can be used for the conductor 443.

[0463] A transistor having a convex semiconductor region such as the transistor 441 can be called a fin transistor because it utilizes the convex portion of a semiconductor substrate. Note that an insulator that is in contact with the upper portion of the convex portion and functions as a mask for forming the convex portion may be provided. Although FIG. 15 shows a structure in which the convex portion is formed by processing a part of the substrate 701, a semiconductor having a convex portion may be formed by processing an SOI substrate.

[0464] 15 is just an example, and the transistor 441 is not limited to this configuration and may have an appropriate configuration depending on the circuit configuration, the operation method of the circuit, etc. For example, the transistor 441 may be a planar transistor.

[0465] <<Transistor 601>> The transistor 601 can have a structure similar to that of the transistor 441.

[0466] <<Insulator 405, Insulator 407, Insulator 409, Insulator 411>> In addition to the element isolation layer 403, the transistor 441, and the transistor 601, the insulators 405, 407, 409, and 411 are provided over the substrate 701. A conductor 451 is embedded in the insulator 405, the insulator 407, the insulator 409, and the insulator 411. Here, the height of the top surface of the conductor 451 can be made approximately the same as the height of the top surface of the insulator 411.

[0467] The insulators 405, 407, 409, and 411 each function as an interlayer film and may also function as a planarization film that covers the uneven shapes below each of them.

[0468] <<Insulator 421, Insulator 214, Insulator 216>> The insulator 421 and the insulator 214 are provided over the conductor 451 and the insulator 411. The conductor 453 is embedded in the insulator 421 and the insulator 214. Here, the height of the top surface of the conductor 453 and the height of the top surface of the insulator 214 can be made approximately the same.

[0469] An insulator 216 is provided over the conductor 453 and the insulator 214. A conductor 455 is embedded in the insulator 216. Here, the height of the top surface of the conductor 455 and the height of the top surface of the insulator 216 can be made approximately the same.

[0470] <<Adhesive Layer 459>> An adhesive layer 459 is provided on the insulator 216. A bump 458 is embedded in the adhesive layer 459. The adhesive layer 459 bonds the insulator 216 and the substrate 701B. Furthermore, the lower surface of the bump 458 contacts the conductor 455, and the upper surface of the bump 458 contacts the conductor 305, electrically connecting the conductor 455 and the conductor 305.

[0471] <<Substrate 701B>> A single crystal semiconductor substrate such as a single crystal silicon substrate can be used as the substrate 701B. Note that a semiconductor substrate other than a single crystal semiconductor substrate may also be used as the substrate 701B.

[0472] A transistor 750 is provided over a substrate 701B. The transistor 750 can be the transistor provided in the layer 30 described in Embodiment 3. For example, the transistor 750 can be the transistor provided in the pixel circuit 62.

[0473] <<Transistor 750 >> The transistor 750 can have a structure similar to that of the transistor 441 .

[0474] <<Insulator 405B, Insulator 280, Insulator 274, Insulator 281>> In addition to the element isolation layer 403B and the transistor 750, the insulator 405B, the insulator 280, the insulator 274, and the insulator 281 are provided over the substrate 701B. The conductor 305 is embedded in the insulator 405B, the insulator 280, the insulator 274, and the insulator 281. Here, the height of the top surface of the conductor 305 and the height of the top surface of the insulator 281 can be made approximately the same.

[0475] The insulator 405B, the insulator 280, the insulator 274, and the insulator 281 function as interlayer films and may also function as planarizing films that cover the uneven shapes below them.

[0476] <<Insulator 361 >> The insulator 361 is provided over the conductor 305 and the insulator 281 .

[0477] <<Transistor 441>> As shown in Figure 15, the low-resistance region 449b, which functions as the other of the source region and the drain region of the transistor 441, is electrically connected to the FPC 716 via the conductor 451, the conductor 453, the conductor 455, the bump 458, the conductor 305, the conductor 317, the conductor 337, the conductor 347, the conductor 353, the conductor 355, the conductor 357, the connection electrode 760, and the anisotropic conductor 780.

[0478] <Configuration Example 4 of Display Device> The display device 10 illustrated in FIG. 16 is mainly different from the display device 10 illustrated in FIG. 14 in that the transistors 602 and 603 are OS transistors instead of the transistors 441 and 601. The transistor 750 can be an OS transistor. That is, the display device 10 illustrated in FIG. 14 has a stack of OS transistors. Note that FIG. 16 illustrates an example in which the transistors 602 and 603 are provided over a substrate 701. As described above, the substrate 701 can be a single-crystal semiconductor substrate such as a single-crystal silicon substrate or another semiconductor substrate. Alternatively, the substrate 701 can be any of various insulator substrates such as a glass substrate or a sapphire substrate.

[0479] <Insulator 613 and Insulator 614> The insulator 613 and the insulator 614 are provided over the substrate 701, and the transistor 602 and the transistor 603 are provided over the insulator 614. Note that a transistor or the like may be provided between the substrate 701 and the insulator 613. For example, transistors having structures similar to those of the transistor 441 and the transistor 601 shown in FIG. 14 may be provided between the substrate 701 and the insulator 613.

[0480] <<Transistor 602 and Transistor 603>> The transistor 602 and the transistor 603 can be the transistors provided in the layer 20 described in Embodiment 3.

[0481] The transistors 602 and 603 can have a structure similar to that of the transistor 750. Note that the transistors 602 and 603 may be OS transistors having a different structure from that of the transistor 750.

[0482] <<Insulators 616, 622, 624, 654, 680, 674, and 681>> In addition to the transistors 602 and 603, the insulators 616, 622, 624, 654, 680, 674, and 681 are provided over the insulator 614. The conductor 461 is embedded in the insulators 654, 680, 674, and 681. Here, the height of the top surface of the conductor 461 can be made approximately the same as the height of the top surface of the insulator 681.

[0483] <<Insulator 501>> The insulator 501 is provided over the conductor 461 and the insulator 681. The conductor 463 is embedded in the insulator 501. Here, the height of the top surface of the conductor 463 and the height of the top surface of the insulator 501 can be made approximately the same.

[0484] The insulators 421 and 214 are provided over the conductor 463 and the insulator 501. The conductor 453 is embedded in the insulator 421 and the insulator 214. Here, the height of the top surface of the conductor 453 and the height of the top surface of the insulator 214 can be made approximately the same.

[0485] As shown in Figure 16, one of the source and drain of transistor 602 is electrically connected to FPC 716 via conductor 461, conductor 463, conductor 453, conductor 455, conductor 305, conductor 317, conductor 337, conductor 347, conductor 353, conductor 355, conductor 357, connection electrode 760, and anisotropic conductor 780.

[0486] Conductor 305 is embedded in insulator 222, insulator 224, insulator 254, insulator 280, insulator 274, and insulator 281. Here, the height of the top surface of conductor 305 and the height of the top surface of insulator 281 can be made approximately the same.

[0487] The insulators 613, 614, 680, 674, 681, and 501 function as interlayer films and may also function as planarizing films that cover the uneven shapes below them.

[0488] 16 , the display device 10 can have a narrower frame and be smaller, and all of the transistors included in the display device 10 can be OS transistors. This allows, for example, the transistors provided in the layer 20 and the transistors provided in the layer 30 described in Embodiment 3 to be manufactured using the same device. Therefore, the manufacturing cost of the display device 10 can be reduced, and the display device 10 can be manufactured at a low price.

[0489] 17 is a cross-sectional view illustrating a structural example of a display device 10. The display device 10 mainly differs from the display device 10 illustrated in FIG. 14 in that a layer including a transistor 800 is provided between a layer including a transistor 750 and a layer including a transistor 601 and a transistor 441.

[0490] 17 , the layer 20 described in Embodiment 3 can be formed from a layer including the transistors 601 and 441 and a layer including the transistor 800. The transistor 750 can be the transistor provided in the layer 30 described in Embodiment 3.

[0491] <<Insulator 821, Insulator 814>> The insulator 821 and the insulator 814 are provided over the conductor 451 and the insulator 411. The conductor 853 is embedded in the insulator 821 and the insulator 814. Here, the height of the top surface of the conductor 853 and the height of the top surface of the insulator 814 can be made approximately the same.

[0492] <<Insulator 816>> An insulator 816 is provided over the conductor 853 and the insulator 814. A conductor 855 is embedded in the insulator 816. Here, the height of the top surface of the conductor 855 and the height of the top surface of the insulator 816 can be made approximately the same.

[0493] <<Insulators 822, 824, 854, 880, 874, and 881>> Insulators 822, 824, 854, 880, 874, and 881 are provided on the conductor 855 and the insulator 816. The conductor 805 is embedded in the insulators 822, 824, 854, 880, 874, and 881. Here, the height of the top surface of the conductor 805 and the height of the top surface of the insulator 881 can be made approximately the same.

[0494] The insulator 421 and the insulator 214 are provided over the conductor 817 and the insulator 881 .

[0495] As shown in Figure 17, the low resistance region 449b, which functions as the other of the source region and drain region of the transistor 441, is electrically connected to the FPC 716 via conductor 451, conductor 853, conductor 855, conductor 805, conductor 817, conductor 453, conductor 455, conductor 305, conductor 317, conductor 337, conductor 347, conductor 353, conductor 355, conductor 357, connection electrode 760, and anisotropic conductor 780.

[0496] <<Transistor 800>> The transistor 800 is provided over the insulator 814. The transistor 800 can be the transistor provided in the layer 20 described in Embodiment 3. The transistor 800 is preferably an OS transistor. For example, the transistor 800 can be a transistor provided in the backup circuit 82.

[0497] Conductors 801a and 801b are embedded in the insulators 854, 880, 874, and 881. The conductor 801a is electrically connected to one of the source and the drain of the transistor 800, and the conductor 801b is electrically connected to the other of the source and the drain of the transistor 800. Here, the height of the top surfaces of the conductors 801a and 801b can be made approximately the same as the height of the top surface of the insulator 881.

[0498] <<Transistor 750>> The transistor 750 can be the transistor provided in the layer 30 described in Embodiment 3. For example, the transistor 750 can be a transistor provided in the pixel circuit 62. The transistor 750 is preferably an OS transistor.

[0499] Insulator 405, insulator 407, insulator 409, insulator 411, insulator 821, insulator 814, insulator 880, insulator 874, insulator 881, insulator 421, insulator 214, insulator 280, insulator 274, insulator 281, insulator 361, and insulator 363 function as interlayer films and may also function as planarizing films that cover the uneven shapes below each other.

[0500] 17 shows an example in which a conductor 801a, a conductor 801b, and a conductor 805 are formed in the same layer. Also shown is an example in which a conductor 811, a conductor 813, and a conductor 817 are formed in the same layer.

[0501] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0502] Embodiment 5 In this embodiment, a transistor that can be used in a display device that is one embodiment of the present invention will be described.

[0503] 18A, 18B, and 18C are a top view and a cross-sectional view of a transistor 200A that can be used in a display device of one embodiment of the present invention and a periphery of the transistor 200A. The transistor 200A can be applied to the display device of one embodiment of the present invention.

[0504] FIG. 18A is a top view of the transistor 200A. Also, FIGS. 18B and 18C are cross-sectional views of the transistor 200A. Here, FIG. 18B is a cross-sectional view of a portion indicated by a dashed dotted line A1-A2 in FIG. 18A and is also a cross-sectional view of the transistor 200A in the channel length direction. Also, FIG. 18C is a cross-sectional view of a portion indicated by a dashed dotted line A3-A4 in FIG. 18A and is also a cross-sectional view of the transistor 200A in the channel width direction. Note that in the top view of FIG. 18A, some elements are omitted for clarity.

[0505] As shown in FIG. 18 , the transistor 200A includes a metal oxide 230a disposed on a substrate (not shown), a metal oxide 230b disposed on the metal oxide 230a, a conductor 242a and a conductor 242b disposed spaced apart from each other on the metal oxide 230b, an insulator 280 disposed on the conductors 242a and 242b and having an opening formed between the conductors 242a and 242b, a conductor 260 disposed in the opening, an insulator 250 disposed among the metal oxide 230b, the conductors 242a, the conductors 242b, the insulator 280, and the conductor 260, and a metal oxide 230c disposed among the metal oxide 230b, the conductors 242a, the conductors 242b, the insulator 280, and the insulator 250. 18B and 18C , it is preferable that the top surface of the conductor 260 substantially coincides with the top surfaces of the insulators 250, 254, metal oxide 230c, and 280. Note that, hereinafter, the metal oxides 230a, 230b, and 230c may be collectively referred to as the metal oxides 230. Furthermore, the conductors 242a and 242b may be collectively referred to as the conductors 242.

[0506] 18 , the side surfaces of the conductors 242a and 242b facing the conductor 260 have a substantially vertical shape. Note that the transistor 200A shown in FIG. 18 is not limited to this, and the angle formed between the side surface and the bottom surface of the conductors 242a and 242b may be 10° to 80°, preferably 30° to 60°. Furthermore, the opposing side surfaces of the conductors 242a and 242b may have multiple surfaces.

[0507] 18 , it is preferable that an insulator 254 be disposed between the insulator 224, the metal oxide 230a, the metal oxide 230b, the conductor 242a, the conductor 242b, and the metal oxide 230c and the insulator 280. Here, it is preferable that the insulator 254 be in contact with the side surface of the metal oxide 230c, the top and side surfaces of the conductor 242a, the top and side surfaces of the conductor 242b, the side surfaces of the metal oxide 230a and the metal oxide 230b, and the top surface of the insulator 224, as shown in FIGS.

[0508] Although the transistor 200A has a three-layer structure of the metal oxide 230a, the metal oxide 230b, and the metal oxide 230c in and around a region where a channel is formed (hereinafter also referred to as a channel formation region), the present invention is not limited to this. For example, a two-layer structure of the metal oxide 230b and the metal oxide 230c or a stacked structure of four or more layers may be provided. Furthermore, the transistor 200A has a two-layer structure of the conductor 260, but the present invention is not limited to this. For example, the conductor 260 may have a single-layer structure or a stacked structure of three or more layers. Furthermore, each of the metal oxide 230a, the metal oxide 230b, and the metal oxide 230c may have a stacked structure of two or more layers.

[0509] For example, when metal oxide 230c has a layered structure consisting of a first metal oxide and a second metal oxide on the first metal oxide, it is preferable that the first metal oxide has a composition similar to that of metal oxide 230b, and the second metal oxide has a composition similar to that of metal oxide 230a.

[0510] Here, the conductor 260 functions as the gate electrode of the transistor, and the conductors 242a and 242b function as source and drain electrodes, respectively. As described above, the conductor 260 is formed so as to be embedded in the opening of the insulator 280 and in the region sandwiched between the conductors 242a and 242b. Here, the arrangements of the conductors 260, 242a, and 242b are selected in a self-aligned manner with respect to the opening of the insulator 280. That is, in the transistor 200A, the gate electrode can be arranged between the source and drain electrodes in a self-aligned manner. Therefore, the conductor 260 can be formed without providing an alignment margin, thereby reducing the area occupied by the transistor 200A. This allows for a high-resolution display device. Furthermore, the display device can have a narrow frame.

[0511] As shown in FIG. 18, the conductor 260 preferably has a conductor 260a provided inside the insulator 250 and a conductor 260b provided so as to be embedded inside the conductor 260a.

[0512] The transistor 200A preferably includes an insulator 214 disposed on a substrate (not shown), an insulator 216 disposed on the insulator 214, a conductor 205 disposed so as to be embedded in the insulator 216, an insulator 222 disposed on the insulator 216 and the conductor 205, and an insulator 224 disposed on the insulator 222. A metal oxide 230a is preferably disposed on the insulator 224.

[0513] An insulator 274 functioning as an interlayer film and an insulator 281 are preferably provided over the transistor 200A. Here, the insulator 274 is preferably provided in contact with top surfaces of the conductor 260, the insulator 250, the insulator 254, the metal oxide 230c, and the insulator 280.

[0514] It is preferable that the insulators 222, 254, and 274 have the function of suppressing the diffusion of at least one of hydrogen (e.g., hydrogen atoms, hydrogen molecules, etc.). For example, it is preferable that the insulators 222, 254, and 274 have lower hydrogen permeability than the insulators 224, 250, and 280. It is also preferable that the insulators 222 and 254 have the function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms, oxygen molecules, etc.). For example, it is preferable that the insulators 222 and 254 have lower oxygen permeability than the insulators 224, 250, and 280.

[0515] Here, the insulator 224, the metal oxide 230, and the insulator 250 are separated by the insulators 280 and 281, and the insulators 254 and 274. Therefore, impurities such as hydrogen contained in the insulators 280 and 281 or excess oxygen can be prevented from being mixed into the insulators 224, the metal oxide 230a, the metal oxide 230b, and the insulator 250.

[0516] It is preferable that a conductor 240 (conductor 240a and conductor 240b) electrically connected to the transistor 200A and functioning as a plug be provided. Note that an insulator 241 (insulator 241a and insulator 241b) is provided in contact with the side surface of the conductor 240 functioning as a plug. That is, the insulator 241 is provided in contact with the inner walls of the openings of the insulators 254, 280, 274, and 281. Alternatively, a first conductor of the conductor 240 may be provided in contact with the side surface of the insulator 241, and a second conductor of the conductor 240 may be provided further inside. Here, the height of the top surface of the conductor 240 and the height of the insulator 281 can be made approximately the same. Note that, although the transistor 200A illustrates a structure in which the first conductor of the conductor 240 and the second conductor of the conductor 240 are stacked, the present invention is not limited to this. For example, the conductor 240 may be configured to have a single layer or a laminated structure of three or more layers. When the structure has a laminated structure, the layers may be distinguished by assigning ordinal numbers to indicate the order of formation.

[0517] In the transistor 200A, a metal oxide that functions as an oxide semiconductor (hereinafter also referred to as an oxide semiconductor) is preferably used for the metal oxide 230 (the metal oxide 230a, the metal oxide 230b, and the metal oxide 230c) including the channel formation region. For example, a metal oxide having a band gap of 2 eV or more, preferably 2.5 eV or more, is preferably used as the metal oxide that forms the channel formation region of the metal oxide 230.

[0518] The metal oxide preferably contains at least indium (In) or zinc (Zn). In particular, it is preferable that it contains indium (In) and zinc (Zn). Furthermore, it is preferable that it contains an element M in addition to these. The element M can be one or more of aluminum (Al), gallium (Ga), yttrium (Y), tin (Sn), boron (B), titanium (Ti), iron (Fe), nickel (Ni), germanium (Ge), zirconium (Zr), molybdenum (Mo), lanthanum (La), cerium (Ce), neodymium (Nd), hafnium (Hf), tantalum (Ta), tungsten (W), magnesium (Mg), or cobalt (Co). In particular, it is preferable that the element M is one or more of aluminum (Al), gallium (Ga), yttrium (Y), or tin (Sn). Furthermore, it is more preferable that the element M contains either or both of Ga and Sn.

[0519] 18B , the film thickness of the metal oxide 230b in the region that does not overlap with the conductor 242 may be thinner than the film thickness of the region that overlaps with the conductor 242. This is formed by removing a portion of the upper surface of the metal oxide 230b when forming the conductors 242a and 242b. When a conductive film that will become the conductor 242 is formed on the upper surface of the metal oxide 230b, a low-resistance region may be formed near the interface with the conductive film. In this way, by removing the low-resistance region located between the conductors 242a and 242b on the upper surface of the metal oxide 230b, it is possible to prevent a channel from being formed in that region.

[0520] According to one embodiment of the present invention, a display device having high definition and a small transistor can be provided. Alternatively, a display device having high luminance and a transistor with high on-state current can be provided. Alternatively, a display device having high-speed operation and a transistor with stable electrical characteristics can be provided. Alternatively, a display device having low power consumption and a transistor with low off-state current can be provided.

[0521] The detailed structure of the transistor 200A that can be used in the display device of one embodiment of the present invention will be described.

[0522] The conductor 205 is arranged to have a region overlapping with the metal oxide 230 and the conductor 260. The conductor 205 is preferably embedded in the insulator 216.

[0523] The conductor 205 includes conductor 205a, conductor 205b, and conductor 205c. The conductor 205a is provided in contact with the bottom surface and sidewall of an opening provided in the insulator 216. The conductor 205b is provided so as to be embedded in a recess formed in the conductor 205a. Here, the top surface of the conductor 205b is lower than the top surface of the conductor 205a and the top surface of the insulator 216. The conductor 205c is provided in contact with the top surface of the conductor 205b and the side surface of the conductor 205a. Here, the height of the top surface of the conductor 205c is approximately the same as the height of the top surface of the conductor 205a and the height of the top surface of the insulator 216. In other words, the conductor 205b is configured to be enclosed by the conductors 205a and 205c.

[0524] The conductors 205a and 205c are preferably made of a conductive material that has a function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (NO, NO, NO, etc.), copper atoms, etc. Alternatively, it is preferable to use a conductive material that has a function of suppressing the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.).

[0525] By using a conductive material that has the function of reducing hydrogen diffusion for the conductor 205a and the conductor 205c, it is possible to prevent impurities such as hydrogen contained in the conductor 205b from diffusing into the metal oxide 230 via the insulator 224 or the like. Furthermore, by using a conductive material that has the function of suppressing oxygen diffusion for the conductor 205a and the conductor 205c, it is possible to prevent the conductor 205b from being oxidized and its conductivity from decreasing. Examples of conductive materials that have the function of suppressing oxygen diffusion include titanium, titanium nitride, tantalum, tantalum nitride, ruthenium, and ruthenium oxide. Therefore, the conductor 205a may be formed as a single layer or a multilayer structure using the above-mentioned conductive materials. For example, the conductor 205a may be made of titanium nitride.

[0526] The conductor 205b is preferably made of a conductive material containing tungsten, copper, or aluminum as a main component, for example, tungsten.

[0527] Here, the conductor 260 may function as a first gate (also referred to as a top gate) electrode. The conductor 205 may function as a second gate (also referred to as a bottom gate) electrode. In this case, the potential applied to the conductor 205 may be changed independently of the potential applied to the conductor 260, thereby controlling the V ｔｈ In particular, applying a negative potential to the conductor 205 can control the V ｔｈ Therefore, when a negative potential is applied to the conductor 205, the drain current when the potential applied to the conductor 260 is 0 V can be made smaller than when no negative potential is applied.

[0528] The conductor 205 is preferably provided to be larger than the channel formation region in the metal oxide 230. In particular, as shown in Fig. 18C, the conductor 205 preferably extends also in a region outside the end portion intersecting with the channel width direction of the metal oxide 230. In other words, outside the side surface of the metal oxide 230 in the channel width direction, the conductor 205 and the conductor 260 preferably overlap with each other via an insulator.

[0529] With the above structure, the channel formation region of the metal oxide 230 can be electrically surrounded by the electric field of the conductor 260 that functions as a first gate electrode and the electric field of the conductor 205 that functions as a second gate electrode.

[0530] 18C, the conductor 205 is extended to function as wiring. However, the present invention is not limited to this, and a conductor functioning as wiring may be provided below the conductor 205.

[0531] The insulator 214 preferably functions as a barrier insulating film that prevents impurities such as water or hydrogen from entering the transistor 200A from the substrate side. Therefore, the insulator 214 prevents hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, and nitrogen oxide molecules (N ２ O, NO, NO ２ It is preferable to use an insulating material that has a function of suppressing the diffusion of impurities such as copper atoms (i.e., copper atoms are less likely to penetrate the impurities), or that has a function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms, oxygen molecules, etc.) (i.e., oxygen is less likely to penetrate the insulating material).

[0532] For example, it is preferable to use aluminum oxide, silicon nitride, or the like as the insulator 214. This can prevent impurities such as water or hydrogen from diffusing from the substrate side of the insulator 214 to the transistor 200A side. Alternatively, it can prevent oxygen contained in the insulator 224 or the like from diffusing toward the substrate side of the insulator 214.

[0533] The insulators 216, 280, and 281, which function as interlayer films, preferably have a lower dielectric constant than the insulator 214. Using a material with a low dielectric constant as the interlayer film can reduce parasitic capacitance between wirings. For example, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide to which fluorine has been added, silicon oxide to which carbon has been added, silicon oxide to which carbon and nitrogen have been added, silicon oxide having vacancies, or the like can be used as appropriate for the insulators 216, 280, and 281.

[0534] The insulators 222 and 224 function as gate insulators.

[0535] Here, the insulator 224 in contact with the metal oxide 230 preferably releases oxygen upon heating. In this specification, oxygen released upon heating is sometimes referred to as excess oxygen. For example, the insulator 224 may be made of silicon oxide, silicon oxynitride, or the like as appropriate. By providing an insulator containing oxygen in contact with the metal oxide 230, oxygen vacancies in the metal oxide 230 can be reduced, and the reliability of the transistor 200A can be improved.

[0536] Specifically, an oxide material from which some oxygen is released by heating is preferably used as the insulator 224. The oxide from which oxygen is released by heating is an oxide from which the amount of released oxygen converted into oxygen atoms is 1.0×10 in thermal desorption spectroscopy (TDS) analysis. １８ atoms / cm ３ or more, preferably 1.0 × 10 １９ atoms / cm ３ More preferably, 2.0 × 10 １９ atoms / cm ３ or more, or 3.0 x 10 ２０ atoms / cm ３ The surface temperature of the film during the TDS analysis is preferably in the range of 100°C or higher and 700°C or lower, or 100°C or higher and 400°C or lower.

[0537] 18C , the thickness of the region of insulator 224 that does not overlap with insulator 254 and metal oxide 230b may be thinner than the thickness of the other region. It is preferable that the thickness of the region of insulator 224 that does not overlap with insulator 254 and metal oxide 230b is a thickness that allows sufficient diffusion of the oxygen.

[0538] Like the insulator 214, the insulator 222 preferably functions as a barrier insulating film that prevents impurities such as water or hydrogen from entering the transistor 200A from the substrate side. For example, the insulator 222 preferably has lower hydrogen permeability than the insulator 224. By surrounding the insulator 224, the metal oxide 230, the insulator 250, etc. with the insulators 222, 254, and 274, impurities such as water or hydrogen can be prevented from entering the transistor 200A from the outside.

[0539] Furthermore, it is preferable that the insulator 222 has a function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms, oxygen molecules, etc.) (i.e., the oxygen is less likely to permeate). For example, it is preferable that the insulator 222 has lower oxygen permeability than the insulator 224. The insulator 222 has a function of suppressing the diffusion of oxygen or impurities, which is preferable because it can reduce the diffusion of oxygen contained in the metal oxide 230 toward the substrate side. Furthermore, it can suppress the reaction of the conductor 205 with the insulator 224 or the oxygen contained in the metal oxide 230.

[0540] The insulator 222 may be an insulator containing an oxide of one or both of insulating materials, such as aluminum and hafnium. Examples of the insulator containing an oxide of one or both of aluminum and hafnium include aluminum oxide, hafnium oxide, and oxide containing aluminum and hafnium (hafnium aluminate). When the insulator 222 is formed using such a material, the insulator 222 functions as a layer that suppresses oxygen release from the metal oxide 230 or the intrusion of impurities such as hydrogen into the metal oxide 230 from the periphery of the transistor 200A.

[0541] Alternatively, for example, aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, or zirconium oxide may be added to these insulators. Alternatively, these insulators may be nitrided. Silicon oxide, silicon oxynitride, or silicon nitride may be stacked on the above insulators.

[0542] The insulator 222 may be made of, for example, aluminum oxide, hafnium oxide, tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), or strontium titanate (SrTiO ３ ) or (Ba,Sr)TiO ３ Insulators containing so-called high-k materials such as BST may be used in a single layer or a multilayer configuration. As transistors become smaller and more highly integrated, problems such as leakage current may occur due to thinner gate insulators. By using a high-k material as the insulator that functions as the gate insulator, it is possible to reduce the gate potential during transistor operation while maintaining the physical film thickness.

[0543] The insulator 222 and the insulator 224 may have a stacked structure of two or more layers. In this case, the stacked structure is not limited to a stacked structure made of the same material, and may be a stacked structure made of different materials. For example, an insulator similar to the insulator 224 may be provided below the insulator 222.

[0544] The metal oxide 230 includes a metal oxide 230a, a metal oxide 230b on the metal oxide 230a, and a metal oxide 230c on the metal oxide 230b. By providing the metal oxide 230a below the metal oxide 230b, it is possible to suppress the diffusion of impurities from structures formed below the metal oxide 230a to the metal oxide 230b. Furthermore, by providing the metal oxide 230c on the metal oxide 230b, it is possible to suppress the diffusion of impurities from structures formed above the metal oxide 230c to the metal oxide 230b.

[0545] The metal oxide 230 preferably has a stacked structure of multiple oxide layers with different atomic ratios of each metal atom. For example, when the metal oxide 230 contains at least indium (In) and the element M, the ratio of the number of atoms of the element M contained in the metal oxide 230a to the number of atoms of all elements constituting the metal oxide 230a is preferably higher than the ratio of the number of atoms of the element M contained in the metal oxide 230b to the number of atoms of all elements constituting the metal oxide 230b. Furthermore, the atomic ratio of the element M contained in the metal oxide 230a to In is preferably higher than the atomic ratio of the element M contained in the metal oxide 230b to In. Here, the metal oxide 230c can be the same as the metal oxide 230a or the metal oxide 230b.

[0546] The energy of the conduction band minimum of the metal oxide 230a and the metal oxide 230c is preferably higher than the energy of the conduction band minimum of the metal oxide 230b. In other words, the electron affinity of the metal oxide 230a and the metal oxide 230c is preferably lower than the electron affinity of the metal oxide 230b. In this case, the metal oxide 230c is preferably a metal oxide that can be used for the metal oxide 230a. Specifically, the ratio of the number of atoms of the element M contained in the metal oxide 230c to the number of atoms of all elements constituting the metal oxide 230c is preferably higher than the ratio of the number of atoms of the element M contained in the metal oxide 230b to the number of atoms of all elements constituting the metal oxide 230b. Furthermore, the atomic ratio of the element M contained in the metal oxide 230c to In is preferably higher than the atomic ratio of the element M contained in the metal oxide 230c to In.

[0547] Here, the energy level of the conduction band minimum changes smoothly at the junction between the metal oxide 230a, the metal oxide 230b, and the metal oxide 230c. In other words, the energy level of the conduction band minimum at the junction between the metal oxide 230a, the metal oxide 230b, and the metal oxide 230c changes continuously or forms a continuous junction. To achieve this, it is advisable to reduce the defect level density of the mixed layer formed at the interface between the metal oxide 230a and the metal oxide 230b and the interface between the metal oxide 230b and the metal oxide 230c.

[0548] Specifically, the metal oxide 230a and the metal oxide 230b, and the metal oxide 230b and the metal oxide 230c, have a common element other than oxygen (as a main component), thereby forming a mixed layer with a low defect level density. For example, when the metal oxide 230b is an In—Ga—Zn oxide, the metal oxide 230a and the metal oxide 230c may be made of an In—Ga—Zn oxide, a Ga—Zn oxide, gallium oxide, or the like. The metal oxide 230c may also have a stacked structure. For example, a stacked structure of an In—Ga—Zn oxide and a Ga—Zn oxide on the In—Ga—Zn oxide, or a stacked structure of an In—Ga—Zn oxide and a gallium oxide on the In—Ga—Zn oxide, may be used. In other words, a stacked structure of an In—Ga—Zn oxide and an oxide not containing In may be used as the metal oxide 230c.

[0549] Specifically, the metal oxide 230a may have an atomic ratio of In:Ga:Zn=1:3:4 or 1:1:0.5. The metal oxide 230b may have an atomic ratio of In:Ga:Zn=4:2:3 or 3:1:2. The metal oxide 230c may have an atomic ratio of In:Ga:Zn=1:3:4, In:Ga:Zn=4:2:3, Ga:Zn=2:1, or Ga:Zn=2:5. Specific examples of the metal oxide 230c having a stacked structure include a stacked structure of In:Ga:Zn=4:2:3 [atomic ratio] and Ga:Zn=2:1 [atomic ratio], a stacked structure of In:Ga:Zn=4:2:3 [atomic ratio] and Ga:Zn=2:5 [atomic ratio], and a stacked structure of In:Ga:Zn=4:2:3 [atomic ratio] and gallium oxide.

[0550] In this case, the main carrier path is the metal oxide 230b. By configuring the metal oxide 230a and the metal oxide 230c as described above, the defect state density at the interface between the metal oxide 230a and the metal oxide 230b and at the interface between the metal oxide 230b and the metal oxide 230c can be reduced. This reduces the effect of interface scattering on carrier conduction, allowing the transistor 200A to achieve a high on-state current and high frequency characteristics. Note that when the metal oxide 230c has a stacked structure, in addition to the effect of reducing the defect state density at the interface between the metal oxide 230b and the metal oxide 230c, it is expected that the diffusion of constituent elements of the metal oxide 230c toward the insulator 250 can be suppressed. More specifically, by configuring the metal oxide 230c as a stacked structure and positioning an oxide not containing In above the stacked structure, it is possible to suppress In that may diffuse toward the insulator 250. The insulator 250 functions as a gate insulator, and diffusion of In can result in poor transistor characteristics. Therefore, by forming the metal oxide 230c into a stacked structure, it is possible to provide a highly reliable display device.

[0551] Conductors 242 (conductors 242a and 242b) functioning as a source electrode and a drain electrode are provided on the metal oxide 230b. The conductor 242 is preferably a metal element selected from aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, indium, ruthenium, iridium, strontium, or lanthanum, or an alloy containing any of the above metal elements, or an alloy combining any of the above metal elements. For example, tantalum nitride, titanium nitride, tungsten, a nitride containing titanium and aluminum, a nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, an oxide containing strontium and ruthenium, or an oxide containing lanthanum and nickel is preferably used. In addition, tantalum nitride, titanium nitride, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, and oxides containing lanthanum and nickel are preferred because they are conductive materials that are resistant to oxidation or materials that maintain their conductivity even when they absorb oxygen.

[0552] By providing the conductor 242 so as to be in contact with the metal oxide 230, the oxygen concentration may be reduced in the vicinity of the conductor 242 of the metal oxide 230. Furthermore, a metal compound layer containing the metal contained in the conductor 242 and components of the metal oxide 230 may be formed in the vicinity of the conductor 242 of the metal oxide 230. In such a case, the carrier density increases in the region of the metal oxide 230 in the vicinity of the conductor 242, and this region becomes a low-resistance region.

[0553] Here, the region between the conductor 242a and the conductor 242b is formed to overlap the opening of the insulator 280. This allows the conductor 260 to be arranged in a self-aligned manner between the conductor 242a and the conductor 242b.

[0554] The insulator 250 functions as a gate insulator. The insulator 250 is preferably disposed in contact with the upper surface of the metal oxide 230c. The insulator 250 can be made of silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide doped with fluorine, silicon oxide doped with carbon, silicon oxide doped with carbon and nitrogen, or silicon oxide having vacancies. Silicon oxide and silicon oxynitride are particularly preferred because they are stable against heat.

[0555] The insulator 250 preferably has a reduced concentration of impurities such as water or hydrogen, similar to the insulator 224. The thickness of the insulator 250 is preferably 1 nm or more and 20 nm or less.

[0556] A metal oxide may be provided between the insulator 250 and the conductor 260. The metal oxide preferably suppresses oxygen diffusion from the insulator 250 to the conductor 260. This makes it possible to suppress oxidation of the conductor 260 due to oxygen in the insulator 250.

[0557] The metal oxide may function as part of the gate insulator. Therefore, when silicon oxide or silicon oxynitride is used for the insulator 250, it is preferable to use a metal oxide that is a high-k material with a high dielectric constant. By forming the gate insulator into a stacked structure of the insulator 250 and the metal oxide, a stacked structure that is stable against heat and has a high dielectric constant can be obtained. Therefore, it is possible to reduce the gate potential applied during transistor operation while maintaining the physical thickness of the gate insulator. In addition, it is possible to reduce the equivalent oxide thickness (EOT) of the insulator that functions as the gate insulator.

[0558] Specifically, it is possible to use a metal oxide containing one or more selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, magnesium, etc. In particular, it is preferable to use an insulator containing an oxide of either or both of aluminum and hafnium, such as aluminum oxide, hafnium oxide, or an oxide containing aluminum and hafnium (hafnium aluminate).

[0559] Although the conductor 260 is shown as having a two-layer structure in FIG. 18, it may have a single-layer structure or a laminated structure of three or more layers.

[0560] The conductor 260a is a material containing the above-mentioned hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, and nitrogen oxide molecules (N ２ O, NO, NO ２ It is preferable to use a conductor that has a function of suppressing the diffusion of impurities such as copper atoms, etc. Alternatively, it is preferable to use a conductive material that has a function of suppressing the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.).

[0561] The conductor 260a has a function of suppressing oxygen diffusion, which can suppress a decrease in conductivity due to oxidation of the conductor 260b caused by oxygen contained in the insulator 250. As a conductive material having a function of suppressing oxygen diffusion, it is preferable to use, for example, tantalum, tantalum nitride, ruthenium, ruthenium oxide, or the like.

[0562] The conductor 260b is preferably made of a conductive material containing tungsten, copper, or aluminum as a main component. Furthermore, since the conductor 260 also functions as wiring, it is preferable to use a conductor with high conductivity. For example, a conductive material containing tungsten, copper, or aluminum as a main component can be used. Furthermore, the conductor 260b may have a layered structure, such as a layered structure of titanium or titanium nitride and the above-mentioned conductive material.

[0563] 18A and 18C , in a region of the metal oxide 230b that does not overlap with the conductor 242, in other words, in the channel formation region of the metal oxide 230, the side surfaces of the metal oxide 230 are arranged to be covered with the conductor 260. This makes it easier for the electric field of the conductor 260, which functions as the first gate electrode, to act on the side surfaces of the metal oxide 230. This increases the on-state current of the transistor 200A and improves its frequency characteristics.

[0564] Like the insulator 214, the insulator 254 preferably functions as a barrier insulating film that prevents impurities such as water or hydrogen from entering the transistor 200A from the insulator 280 side. For example, the insulator 254 preferably has lower hydrogen permeability than the insulator 224. Furthermore, as shown in FIGS. 18B and 18C , the insulator 254 preferably contacts the side surface of the metal oxide 230c, the top and side surfaces of the conductor 242a, the top and side surfaces of the conductor 242b, the side surfaces of the metal oxide 230a and the metal oxide 230b, and the top surface of the insulator 224. This structure prevents hydrogen contained in the insulator 280 from entering the metal oxide 230 from the top or side surfaces of the conductor 242a, the conductor 242b, the metal oxide 230a, the metal oxide 230b, and the insulator 224.

[0565] Furthermore, it is preferable that the insulator 254 has a function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms, oxygen molecules, etc.) (i.e., the oxygen is less likely to permeate). For example, it is preferable that the insulator 254 has lower oxygen permeability than the insulator 280 or the insulator 224.

[0566] The insulator 254 is preferably formed by a sputtering method. By forming the insulator 254 by a sputtering method in an oxygen-containing atmosphere, oxygen can be added to the insulator 224 near a region in contact with the insulator 254. This allows oxygen to be supplied from this region into the metal oxide 230 through the insulator 224. The insulator 254 has a function of suppressing upward oxygen diffusion, thereby preventing oxygen from diffusing from the metal oxide 230 to the insulator 280. The insulator 222 has a function of suppressing downward oxygen diffusion, thereby preventing oxygen from diffusing from the metal oxide 230 toward the substrate. In this manner, oxygen is supplied to the channel formation region of the metal oxide 230. This reduces oxygen vacancies in the metal oxide 230 and suppresses the transistor from becoming normally on.

[0567] For example, an insulator containing an oxide of one or both of aluminum and hafnium may be formed as the insulator 254. Note that as the insulator containing an oxide of one or both of aluminum and hafnium, aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), or the like is preferably used.

[0568] The insulator 224, the insulator 250, and the metal oxide 230 are covered with the insulator 254, which has a barrier property against hydrogen, so that the insulator 280 is separated from the insulator 224, the metal oxide 230, and the insulator 250 by the insulator 254. This makes it possible to prevent impurities such as hydrogen from penetrating from the outside of the transistor 200A, thereby providing the transistor 200A with good electrical characteristics and reliability.

[0569] The insulator 280 is provided over the insulator 224, the metal oxide 230, and the conductor 242 with the insulator 254 interposed therebetween. For example, the insulator 280 preferably includes silicon oxide, silicon oxynitride, silicon nitride oxide, silicon oxide to which fluorine has been added, silicon oxide to which carbon has been added, silicon oxide to which carbon and nitrogen have been added, silicon oxide having vacancies, or the like. In particular, silicon oxide and silicon oxynitride are preferable because they are thermally stable. In particular, materials such as silicon oxide, silicon oxynitride, and silicon oxide having vacancies are preferable because they can easily form a region containing oxygen that is released by heating.

[0570] It is preferable that the concentration of impurities such as water or hydrogen is reduced in the insulator 280. The top surface of the insulator 280 may be flattened.

[0571] Similar to the insulator 214, the insulator 274 preferably functions as a barrier insulating film that prevents impurities such as water or hydrogen from entering the insulator 280 from above. As the insulator 274, for example, an insulator that can be used for the insulator 214, the insulator 254, etc. may be used.

[0572] An insulator 281 functioning as an interlayer film is preferably provided over the insulator 274. Like the insulator 224, the insulator 281 preferably has a reduced concentration of impurities such as water or hydrogen.

[0573] The conductor 240a and the conductor 240b are arranged in openings formed in the insulator 281, the insulator 274, the insulator 280, and the insulator 254. The conductor 240a and the conductor 240b are provided opposite each other with the conductor 260 interposed therebetween. Note that the height of the top surfaces of the conductor 240a and the conductor 240b may be flush with the top surface of the insulator 281.

[0574] Note that insulator 241a is provided in contact with the inner walls of the openings of insulators 281, 274, 280, and 254, and a first conductor of conductor 240a is formed in contact with the side surface of insulator 241a. Conductor 242a is located on at least a portion of the bottom of the openings, and conductor 240a is in contact with conductor 242a. Similarly, insulator 241b is provided in contact with the inner walls of the openings of insulators 281, 274, 280, and 254, and a first conductor of conductor 240b is formed in contact with the side surface of insulator 241b. Conductor 242b is located on at least a portion of the bottom of the openings, and conductor 240b is in contact with conductor 242b.

[0575] The conductors 240a and 240b are preferably made of a conductive material containing tungsten, copper, or aluminum as a main component. The conductors 240a and 240b may have a layered structure.

[0576] When the conductor 240 has a layered structure, it is preferable to use the above-mentioned conductors that have the function of suppressing the diffusion of impurities such as water or hydrogen for the conductors in contact with the metal oxide 230a, the metal oxide 230b, the conductor 242, the insulator 254, the insulator 280, the insulator 274, and the insulator 281. For example, it is preferable to use tantalum, tantalum nitride, titanium, titanium nitride, ruthenium, or ruthenium oxide. Furthermore, the conductive material that has the function of suppressing the diffusion of impurities such as water or hydrogen may be used in a single layer or a layered structure. Using such a conductive material can suppress the absorption of oxygen added to the insulator 280 by the conductors 240a and 240b. Furthermore, it is possible to suppress the intrusion of impurities such as water or hydrogen from layers above the insulator 281 into the metal oxide 230 through the conductors 240a and 240b.

[0577] The insulators 241a and 241b may be, for example, an insulator that can be used for the insulator 254. The insulators 241a and 241b are provided in contact with the insulator 254, and therefore can prevent impurities such as water or hydrogen from the insulator 280 from being mixed into the metal oxide 230 through the conductors 240a and 240b. Furthermore, oxygen contained in the insulator 280 can be prevented from being absorbed by the conductors 240a and 240b.

[0578] Although not shown, a conductor functioning as wiring may be disposed in contact with the upper surface of the conductor 240a and the upper surface of the conductor 240b. The conductor functioning as wiring is preferably made of a conductive material containing tungsten, copper, or aluminum as a main component. The conductor may also have a layered structure, for example, a layered structure of titanium or titanium nitride and the above-mentioned conductive material. The conductor may be formed so as to be embedded in an opening provided in an insulator.

[0579] <Constituent Materials of Transistor> Constituent materials that can be used for the transistor will be described.

[0580] [Substrate] The substrate on which the transistor 200A is formed may be, for example, an insulating substrate, a semiconductor substrate, or a conductive substrate. Examples of insulating substrates include glass substrates, quartz substrates, sapphire substrates, stabilized zirconia substrates (e.g., yttria-stabilized zirconia substrates), and resin substrates. Examples of semiconductor substrates include semiconductor substrates such as silicon and germanium, or compound semiconductor substrates made of silicon carbide, silicon germanium, gallium arsenide, indium phosphide, zinc oxide, and gallium oxide. Examples of semiconductor substrates include those having an insulating region within the semiconductor substrate, such as an SOI (Silicon-On-Insulator) substrate. Examples of conductive substrates include graphite substrates, metal substrates, alloy substrates, and conductive resin substrates. Examples of substrates include substrates having a metal nitride or a metal oxide. Examples of substrates include an insulating substrate with a conductor or semiconductor provided thereon, a semiconductor substrate with a conductor or insulator provided thereon, and a conductive substrate with a semiconductor or insulator provided thereon. Alternatively, a substrate provided with elements may be used. The elements provided on the substrate include a capacitor element, a resistor element, a switch element, a light-emitting element, a memory element, and the like.

[0581] [Insulator] Examples of insulators include oxides, nitrides, oxynitrides, nitride oxides, metal oxides, metal oxynitrides, and metal nitride oxides, which have insulating properties.

[0582] For example, as transistors become more miniaturized and highly integrated, problems such as leakage current may occur due to thinner gate insulators. Using a high-k material for the insulator that functions as the gate insulator allows for lower voltage operation of the transistor while maintaining the physical film thickness. On the other hand, using a material with a low dielectric constant for the insulator that functions as the interlayer film can reduce the parasitic capacitance that occurs between wiring. Therefore, it is advisable to select a material depending on the function of the insulator.

[0583] Examples of insulators with a high relative dielectric constant include gallium oxide, hafnium oxide, zirconium oxide, oxides containing aluminum and hafnium, oxynitrides containing aluminum and hafnium, oxides containing silicon and hafnium, oxynitrides containing silicon and hafnium, and nitrides containing silicon and hafnium.

[0584] Examples of insulators with a low dielectric constant include silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide doped with fluorine, silicon oxide doped with carbon, silicon oxide doped with carbon and nitrogen, silicon oxide having voids, or resin.

[0585] The electrical characteristics of a transistor including an oxide semiconductor can be stabilized by surrounding it with an insulator (such as the insulator 214, the insulator 222, the insulator 254, and the insulator 274) that has a function of suppressing the permeation of impurities such as hydrogen and oxygen. Examples of insulators that have a function of suppressing the permeation of impurities such as hydrogen and oxygen include, for example, a single-layer or stacked insulator containing boron, carbon, nitrogen, oxygen, fluorine, magnesium, aluminum, silicon, phosphorus, chlorine, argon, gallium, germanium, yttrium, zirconium, lanthanum, neodymium, hafnium, or tantalum. Specifically, examples of insulators that have a function of suppressing the permeation of impurities such as hydrogen and oxygen include metal oxides such as aluminum oxide, magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, and tantalum oxide; and metal nitrides such as aluminum nitride, aluminum titanium nitride, titanium nitride, silicon nitride oxide, and silicon nitride.

[0586] The insulator functioning as the gate insulator is preferably an insulator having a region containing oxygen that is released by heating. For example, by using a structure in which silicon oxide or silicon oxynitride having a region containing oxygen that is released by heating is in contact with the metal oxide 230, oxygen vacancies in the metal oxide 230 can be compensated for.

[0587] [Conductor] As the conductor, it is preferable to use a metal element selected from aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, indium, ruthenium, iridium, strontium, lanthanum, etc., or an alloy containing the above metal element as a component, or an alloy combining the above metal elements. For example, it is preferable to use tantalum nitride, titanium nitride, tungsten, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, oxides containing lanthanum and nickel, etc. Furthermore, tantalum nitride, titanium nitride, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, and oxides containing lanthanum and nickel are preferred because they are conductive materials that are resistant to oxidation or maintain conductivity even when absorbing oxygen. Furthermore, semiconductors with high electrical conductivity, such as polycrystalline silicon containing impurity elements such as phosphorus, and silicides such as nickel silicide may also be used.

[0588] A plurality of conductors formed from the above materials may be stacked. For example, a stacked structure may be formed by combining the above-mentioned material containing a metal element and a conductive material containing oxygen. A stacked structure may also be formed by combining the above-mentioned material containing a metal element and a conductive material containing nitrogen. A stacked structure may also be formed by combining the above-mentioned material containing a metal element, a conductive material containing oxygen, and a conductive material containing nitrogen.

[0589] When a metal oxide is used for the channel formation region of a transistor, a conductor functioning as a gate electrode preferably has a stacked structure of a combination of a material containing the metal element and a conductive material containing oxygen. In this case, the conductive material containing oxygen is preferably provided on the channel formation region side. By providing the conductive material containing oxygen on the channel formation region side, oxygen released from the conductive material is easily supplied to the channel formation region.

[0590] In particular, as a conductor functioning as a gate electrode, it is preferable to use a conductive material containing oxygen and a metal element contained in the metal oxide in which the channel is formed. Alternatively, a conductive material containing the above-mentioned metal element and nitrogen may be used. For example, a conductive material containing nitrogen, such as titanium nitride or tantalum nitride, may be used. Alternatively, indium tin oxide, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium zinc oxide, or indium tin oxide doped with silicon may be used. Furthermore, indium gallium zinc oxide containing nitrogen may be used. By using such a material, hydrogen contained in the metal oxide in which the channel is formed may be captured. Alternatively, hydrogen introduced from an external insulator or the like may be captured.

[0591] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0592] Embodiment 6 In this embodiment, a metal oxide (hereinafter also referred to as an oxide semiconductor) that can be used for the OS transistor described in the above embodiment will be described.

[0593] <Classification of Crystal Structures> First, classification of crystal structures in oxide semiconductors will be described with reference to Fig. 19A. Fig. 19A is a diagram illustrating classification of crystal structures of oxide semiconductors, typically IGZO (metal oxide containing In, Ga, and Zn).

[0594] As shown in FIG. 19A , oxide semiconductors are broadly classified into "amorphous," "crystalline," and "crystal." Furthermore, "amorphous" includes completely amorphous. Furthermore, "crystalline" includes c-axis-aligned crystalline line (CAAC), nanocrystalline line (nc), and cloud-aligned composite (CAC). The "crystalline" classification excludes single crystal, polycrystalline, and completely amorphous. Furthermore, "Crystal" includes single crystal and poly crystal.

[0595] The structure within the bold frame shown in Figure 19A is an intermediate state between "Amorphous" and "Crystal" and belongs to a new boundary region (New crystalline phase). In other words, this structure can be said to be completely different from the energetically unstable "Amorphous" and "Crystal."

[0596] The crystalline structure of the film or substrate can be evaluated using an X-ray diffraction (XRD) spectrum. Here, FIG. 19B shows an XRD spectrum obtained by GIXD (Grazing-Incident XRD) measurement of a CAAC-IGZO film classified as "Crystalline." The GIXD method is also called the thin film method or the Seemann-Bohlin method. Hereinafter, the XRD spectrum obtained by GIXD measurement shown in FIG. 19B will be simply referred to as the XRD spectrum. The composition of the CAAC-IGZO film shown in FIG. 19B is approximately In:Ga:Zn = 4:2:3 [atomic ratio]. The thickness of the CAAC-IGZO film shown in FIG. 19B is 500 nm.

[0597] As shown in Figure 19B, a peak indicating clear crystallinity is detected in the XRD spectrum of the CAAC-IGZO film. Specifically, a peak indicating c-axis orientation is detected near 2θ = 31° in the XRD spectrum of the CAAC-IGZO film. Note that, as shown in Figure 19B, the peak near 2θ = 31° is asymmetric with respect to the angle at which the peak intensity is detected.

[0598] The crystalline structure of the film or substrate can be evaluated by a diffraction pattern (also referred to as a nanobeam electron diffraction pattern) observed by nanobeam electron diffraction (NBED). The diffraction pattern of the CAAC-IGZO film is shown in FIG. 19C. FIG. 19C is a diffraction pattern observed by NBED, in which an electron beam is incident parallel to the substrate. The composition of the CAAC-IGZO film shown in FIG. 19C is near In:Ga:Zn = 4:2:3 [atomic ratio]. In the nanobeam electron diffraction method, electron beam diffraction is performed using a probe diameter of 1 nm.

[0599] As shown in FIG. 19C, multiple spots indicating c-axis orientation are observed in the diffraction pattern of the CAAC-IGZO film.

[0600] [Structure of Oxide Semiconductor] Note that oxide semiconductors may be classified differently from those shown in FIG. 19A when focusing on their crystal structures. For example, oxide semiconductors are classified into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the above-mentioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, pseudo-amorphous-like oxide semiconductors (a-like OSs), amorphous oxide semiconductors, and the like.

[0601] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0602] [CAAC-OS] A CAAC-OS is an oxide semiconductor having multiple crystalline regions, each with its c-axis aligned in a specific direction. The specific direction refers to the thickness direction of the CAAC-OS film, the normal direction to the surface where the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region having periodic atomic arrangement. If the atomic arrangement is considered as a lattice arrangement, a crystalline region is also a region with a uniform lattice arrangement. Furthermore, a CAAC-OS has a region where multiple crystalline regions are connected in the a-b plane direction, and the region may have distortion. Note that distortion refers to a portion where the lattice arrangement changes between a region with a uniform lattice arrangement and a region with another uniform lattice arrangement in a region where multiple crystalline regions are connected. In other words, a CAAC-OS is an oxide semiconductor whose c-axes are aligned and whose orientation is not clearly aligned in the a-b plane direction.

[0603] Each of the multiple crystalline regions is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of a single minute crystal, the maximum diameter of the crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of the crystalline region may be several tens of nanometers.

[0604] In an In-M-Zn oxide (wherein the element M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, and the like), the CAAC-OS tends to have a layered crystal structure (also referred to as a layered structure) in which a layer containing indium (In) and oxygen (hereinafter referred to as an In layer) and a layer containing the element M, zinc (Zn), and oxygen (hereinafter referred to as an (M, Zn) layer) are stacked. Note that indium and the element M are mutually substituted. Therefore, the (M, Zn) layer may contain indium. The In layer may contain the element M. The In layer may contain Zn. The layered structure is observed as a lattice image in a high-resolution TEM image, for example.

[0605] When a CAAC-OS film is subjected to structural analysis using an XRD apparatus, for example, a peak indicating c-axis orientation is detected at or near 2θ = 31° in out-of-plane XRD measurement using θ / 2θ scanning. Note that the position of the peak indicating c-axis orientation (the value of 2θ) may vary depending on the type, composition, and the like of the metal elements constituting the CAAC-OS.

[0606] For example, multiple bright spots are observed in the electron diffraction pattern of a CAAC-OS film, and the observed spots are at positions that are point-symmetric with respect to a spot of an incident electron beam that has passed through the sample (also referred to as a direct spot).

[0607] When a crystalline region is observed from the specific direction, the lattice arrangement in the crystalline region is basically a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be a non-regular hexagon. The distortion may have a pentagonal, heptagonal, or other lattice arrangement. In the CAAC-OS, no clear grain boundary can be identified even near the distortion. This indicates that the distortion in the lattice arrangement suppresses the formation of grain boundaries. This is thought to be because the CAAC-OS can tolerate distortion due to the lack of close-packed arrangement of oxygen atoms in the a-b plane and the change in interatomic bond distance caused by metal atom substitution.

[0608] Note that a crystal structure in which clear grain boundaries are observed is called polycrystalline. The grain boundaries act as recombination centers, and are likely to trap carriers, resulting in a decrease in the on-state current of a transistor and a decrease in field-effect mobility. Therefore, CAAC-OS, in which clear grain boundaries are not observed, is one of the crystalline oxides having a crystal structure suitable for a semiconductor layer of a transistor. Note that a structure containing Zn is preferable for forming a CAAC-OS. For example, In—Zn oxide and In—Ga—Zn oxide are suitable because they can suppress the generation of grain boundaries more effectively than In oxide.

[0609] CAAC-OS is an oxide semiconductor with high crystallinity and no clear crystal grain boundaries. Therefore, it can be said that the CAAC-OS is less susceptible to a decrease in electron mobility due to crystal grain boundaries. Furthermore, since the crystallinity of an oxide semiconductor can be reduced by the inclusion of impurities or the generation of defects, the CAAC-OS can also be said to be an oxide semiconductor with few impurities or defects (oxygen vacancies, etc.). Therefore, an oxide semiconductor having a CAAC-OS has stable physical properties. Therefore, an oxide semiconductor having a CAAC-OS is heat-resistant and highly reliable. Furthermore, the CAAC-OS is stable even against high temperatures (so-called thermal budget) in the manufacturing process. Therefore, using a CAAC-OS for an OS transistor can increase the flexibility of the manufacturing process.

[0610] [nc-OS] The nc-OS has periodic atomic arrangement in a microscopic region (e.g., a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In other words, the nc-OS has microcrystals. Note that the size of the microcrystals is, for example, 1 nm to 10 nm, particularly 1 nm to 3 nm, and therefore the microcrystals are also called nanocrystals. Furthermore, the nc-OS does not exhibit regularity in the crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Therefore, depending on the analysis method, the nc-OS may be indistinguishable from an a-like OS or an amorphous oxide semiconductor. For example, when a structural analysis of an nc-OS film is performed using an XRD apparatus, no peak indicating crystallinity is detected in out-of-plane XRD measurement using θ / 2θ scanning. When an nc-OS film is subjected to electron diffraction (also referred to as selected-area electron diffraction) using an electron beam with a probe diameter larger than that of a nanocrystal (e.g., 50 nm or more), a diffraction pattern resembling a halo pattern is observed. On the other hand, when an nc-OS film is subjected to electron diffraction (also referred to as nanobeam electron diffraction) using an electron beam with a probe diameter close to or smaller than that of a nanocrystal (e.g., 1 nm to 30 nm), an electron diffraction pattern in which multiple spots are observed within a ring-shaped region centered on a direct spot may be obtained.

[0611] [a-Like OS] The a-like OS is an oxide semiconductor having a structure between the nc-OS and the amorphous oxide semiconductor. The a-like OS has a pore or low-density region. That is, the a-like OS has lower crystallinity than the nc-OS and the CAAC-OS. Furthermore, the a-like OS has a higher hydrogen concentration in the film than the nc-OS and the CAAC-OS.

[0612] [Structure of Oxide Semiconductor] Next, the above-described CAC-OS will be described in detail. Note that the CAC-OS relates to a material structure.

[0613] [CAC-OS] CAC-OS is, for example, a material in which elements constituting a metal oxide are unevenly distributed in a size of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof. Note that hereinafter, a state in which one or more metal elements are unevenly distributed in a metal oxide and regions containing the metal elements are mixed in a size of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof, is also referred to as a mosaic or patch state.

[0614] Furthermore, the CAC-OS has a mosaic structure in which a material is separated into a first region and a second region, and the first region is distributed throughout the film (hereinafter also referred to as a cloud structure). That is, the CAC-OS is a composite metal oxide having a structure in which the first region and the second region are mixed.

[0615] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in the In—Ga—Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS in the In—Ga—Zn oxide, the first region is a region where [In] is larger than [In] in the composition of the CAC-OS film. The second region is a region where [Ga] is larger than [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is a region where [In] is larger than [In] in the second region and [Ga] is smaller than [Ga] in the second region. The second region is a region where [Ga] is larger than [Ga] in the first region and [In] is smaller than [In] in the first region.

[0616] Specifically, the first region is a region whose main component is indium oxide, indium zinc oxide, or the like. The second region is a region whose main component is gallium oxide, gallium zinc oxide, or the like. In other words, the first region can be rephrased as a region whose main component is In. The second region can be rephrased as a region whose main component is Ga.

[0617] It should be noted that there are cases where a clear boundary between the first region and the second region cannot be observed.

[0618] For example, in the case of CAC-OS in an In—Ga—Zn oxide, EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX) can confirm that the CAC-OS has a structure in which a region containing In as a main component (first region) and a region containing Ga as a main component (second region) are unevenly distributed and mixed.

[0619] When a CAC-OS is used in a transistor, the conductivity due to the first region and the insulating property due to the second region act complementarily, thereby providing the CAC-OS with a switching function (a function of turning on / off). That is, a CAC-OS has a conductive function in a part of the material and an insulating function in a part of the material, and functions as a semiconductor as a whole. By separating the conductive function and the insulating function, both functions can be maximized. Therefore, by using a CAC-OS in a transistor, a high on-current (I ｏｎ ), high field-effect mobility (μ), and good switching behavior can be achieved.

[0620] Oxide semiconductors have a variety of structures, each of which has different characteristics. The oxide semiconductor of one embodiment of the present invention may include two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-like OS, a CAC-OS, an nc-OS, and a CAAC-OS.

[0621] <Transistor Having Oxide Semiconductor> Next, a case where the oxide semiconductor is used for a transistor will be described.

[0622] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0623] For the transistor, an oxide semiconductor having a low carrier concentration is preferably used. For example, the carrier concentration of the oxide semiconductor is 1×10 １７ cm −３ Below 1 × 10, preferably １５ cm −３ More preferably, 1×10 １３ cm −３ Less than 1×10, more preferably 1×10 １１ cm −３ More preferably, 1×10 １０ cm −３ is less than 1×10 −９ cm −３That is all. Note that in order to reduce the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced to reduce the density of defect states. In this specification and the like, a semiconductor having a low impurity concentration and a low density of defect states is referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. Note that an oxide semiconductor having a low carrier concentration may also be referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor.

[0624] A highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states, and therefore, the density of trap states may also be low.

[0625] Charges trapped in the trap states of an oxide semiconductor take a long time to dissipate and may behave like fixed charges. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high density of trap states may have unstable electrical characteristics.

[0626] Therefore, in order to stabilize the electrical characteristics of a transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. Furthermore, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in the adjacent film. Impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, and the like.

[0627] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0628] When an oxide semiconductor contains silicon or carbon, which is one of Group 14 elements, defect levels are formed in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor and the concentration of silicon or carbon near the interface with the oxide semiconductor (concentration obtained by SIMS) are calculated to be 2×10 １８ atoms / cm ３ Below 2 × 10, preferably １７ atoms / cm ３ The following applies.

[0629] When an oxide semiconductor contains an alkali metal or an alkaline earth metal, defect levels may be formed and carriers may be generated. Therefore, a transistor using an oxide semiconductor containing an alkali metal or an alkaline earth metal is likely to have normally-on characteristics. For this reason, when the concentration of the alkali metal or the alkaline earth metal in the oxide semiconductor obtained by SIMS is 1×10 １８ atoms / cm ３ Below 2 × 10, preferably １６ atoms / cm ３ Do the following:

[0630] When nitrogen is contained in an oxide semiconductor, electrons serving as carriers are generated, the carrier concentration increases, and the semiconductor is likely to become n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor tends to have normally-on characteristics. Alternatively, when nitrogen is contained in an oxide semiconductor, trap states may be formed. As a result, the electrical characteristics of the transistor may become unstable. For this reason, the nitrogen concentration in the oxide semiconductor obtained by SIMS is measured to be 5×10 １９ atoms / cm ３ Less than 5×10 １８ atoms / cm ３ Less than 1×10, more preferably 1×10 １８ atoms / cm ３ or less, more preferably 5 × 10 １７ atoms / cm ３ Do the following:

[0631] Hydrogen contained in an oxide semiconductor reacts with oxygen bonded to a metal atom to form water, which may form an oxygen vacancy. Hydrogen entering the oxygen vacancy may generate electrons as carriers. Furthermore, some of the hydrogen may bond with oxygen bonded to a metal atom to generate electrons as carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. Therefore, it is preferable to reduce the amount of hydrogen in the oxide semiconductor as much as possible. Specifically, the hydrogen concentration in the oxide semiconductor measured by SIMS is 1×10 ２０ atoms / cm ３ less than 1×10１９ atoms / cm ３ less than 5×10 １８ atoms / cm ３ less than 1×10 １８ atoms / cm ３ Make it less than.

[0632] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0633] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0634] Embodiment 7 In this embodiment, an electronic device including a display device and a display system which are one embodiment of the present invention will be described.

[0635] FIG. 20A is a diagram showing the appearance of the head-mounted display 8200.

[0636] The head-mounted display 8200 includes a mounting portion 8201, a lens 8202, a main body 8203, a display portion 8204, and a cable 8205. The mounting portion 8201 has a built-in battery 8206.

[0637] A cable 8205 supplies power from a battery 8206 to the main body 8203. The main body 8203 is provided with a wireless receiver or the like, and can display an image corresponding to received image data or the like on a display portion 8204. In addition, a camera provided in the main body 8203 captures the movement of the user's eyeball or eyelid, and calculates the coordinates of the user's line of sight based on the information, thereby allowing the user's line of sight to be used as an input means.

[0638] The attachment unit 8201 may be provided with a plurality of electrodes at positions that come into contact with the user. The main body 8203 may have a function of recognizing the user's line of sight by detecting a current flowing through the electrodes in accordance with the movement of the user's eyeballs. The main body 8203 may also have a function of monitoring the user's pulse by detecting the current flowing through the electrodes. The attachment unit 8201 may also have various sensors such as a temperature sensor, a pressure sensor, and an acceleration sensor, and may have a function of displaying biological information of the user on the display unit 8204. The attachment unit 8201 may also detect the movement of the user's head, and change the image displayed on the display unit 8204 in accordance with the movement.

[0639] The display device of one embodiment of the present invention can be applied to the display portion 8204. This allows the power consumption of the head-mounted display 8200 to be reduced, and therefore the head-mounted display 8200 can be used continuously for a long period of time. Furthermore, by reducing the power consumption of the head-mounted display 8200, the battery 8206 can be made smaller and lighter, and therefore the head-mounted display 8200 can be made smaller and lighter. This reduces the burden on a user of the head-mounted display 8200, and the user can feel less fatigued.

[0640] 20B, 20C, and 20D are diagrams showing the external appearance of a head-mounted display 8300. The head-mounted display 8300 includes a housing 8301, a display portion 8302, a band-shaped fixture 8304, and a pair of lenses 8305. A battery 8306 is built into the housing 8301, and power can be supplied from the battery 8306 to the display portion 8302 and the like.

[0641] A user can view the display on the display portion 8302 through the lens 8305. Note that it is preferable to arrange the display portion 8302 in a curved manner. By arranging the display portion 8302 in a curved manner, a user can feel a high sense of presence. Note that although the configuration in which one display portion 8302 is provided has been illustrated in this embodiment, the present invention is not limited thereto. For example, two display portions 8302 may be provided. In this case, if one display portion is provided for one eye of the user, three-dimensional display using parallax or the like can be performed.

[0642] Note that the display device of one embodiment of the present invention can be applied to the display portion 8302. This allows the power consumption of the head-mounted display 8300 to be reduced, and therefore the head-mounted display 8300 can be used continuously for a long period of time. Furthermore, by reducing the power consumption of the head-mounted display 8300, the battery 8306 can be made smaller and lighter, and therefore the head-mounted display 8300 can be made smaller and lighter. This reduces the burden on a user of the head-mounted display 8300, and the user can feel less fatigue.

[0643] Next, an example of an electronic device different from the electronic device shown in FIGS. 20A to 20D is shown in FIGS. 21A and 21B.

[0644] The electronic device shown in Figures 21A and 21B has a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connection terminal 9006, a sensor 9007 (including a function to measure force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays), and a battery 9009.

[0645] The electronic device shown in FIGS. 21A and 21B has various functions. For example, it may have a function to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date, or time, a function to control processing using various software (programs), a wireless communication function, a function to connect to various computer networks using the wireless communication function, a function to send or receive various data using the wireless communication function, a function to read programs or data recorded on a recording medium and display them on the display unit, etc. Note that the functions that the electronic device shown in FIGS. 21A and 21B can have are not limited to these, and it may have various other functions. Also, although not shown in FIGS. 21A and 21B , the electronic device may be configured to have multiple display units. Furthermore, the electronic device may be equipped with a camera or the like, and may have functions such as taking still images, taking videos, saving the captured images to a recording medium (external or built-in to the camera), and displaying the captured images on the display unit.

[0646] The electronic device shown in FIGS. 21A and 21B will be described in detail below.

[0647] FIG. 21A is a perspective view showing a mobile information terminal 9101. The mobile information terminal 9101 has one or more functions selected from, for example, a telephone, a notebook, an information viewing device, and the like. Specifically, it can be used as a smartphone. The mobile information terminal 9101 can display text or images on multiple surfaces. For example, three operation buttons 9050 (also referred to as operation icons or simply icons) can be displayed on one surface of the display unit 9001. Information 9051, indicated by a dashed rectangle, can be displayed on the other surface of the display unit 9001. Examples of the information 9051 include an indication of an incoming email, SNS (social networking service), or phone call, the title of the email or SNS, the name of the sender of the email or SNS, the date and time, the remaining battery level, and the strength of the antenna reception. Alternatively, the operation buttons 9050 or the like may be displayed in place of the information 9051.

[0648] The display device of one embodiment of the present invention can be applied to the portable information terminal 9101. This allows the power consumption of the portable information terminal 9101 to be reduced, and therefore the portable information terminal 9101 can be used continuously for a long period of time. Furthermore, by reducing the power consumption of the portable information terminal 9101, the battery 9009 can be made smaller and lighter, and therefore the portable information terminal 9101 can be made smaller and lighter. This allows the portable information terminal 9101 to be more portable.

[0649] FIG. 21B is a perspective view showing a wristwatch-type portable information terminal 9200. The portable information terminal 9200 can execute various applications such as mobile phone, e-mail, text browsing and creation, music playback, Internet communication, and computer games. The display surface of the display unit 9001 is curved, and display can be performed along the curved display surface. FIG. 21B shows an example in which time 9251, operation buttons 9252 (also referred to as operation icons or simply icons), and content 9253 are displayed on the display unit 9001. The content 9253 can be, for example, a video.

[0650] The portable information terminal 9200 is also capable of performing short-range wireless communication according to a communication standard. For example, hands-free conversation is also possible by mutual communication with a wirelessly enabled headset. The portable information terminal 9200 also has a connection terminal 9006, and can directly exchange data with another information terminal via a connector. Charging can also be performed via the connection terminal 9006. Note that charging may be performed by wireless power supply without using the connection terminal 9006.

[0651] The display device of one embodiment of the present invention can be applied to the portable information terminal 9200. This allows the power consumption of the portable information terminal 9200 to be reduced, and therefore the portable information terminal 9200 can be used continuously for a long period of time. Furthermore, by reducing the power consumption of the portable information terminal 9200, the battery 9009 can be made smaller and lighter, and therefore the portable information terminal 9200 can be made smaller and lighter. This allows the portable information terminal 9200 to be more portable.

[0652] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0653] <Additional Notes Regarding the Description of the Present Specification, etc.> The following additional notes will be given regarding the above-described embodiments and the explanations of the respective configurations in the embodiments.

[0654] The configurations shown in each embodiment can be combined with the configurations shown in other embodiments as appropriate to form one aspect of the present invention. In addition, when multiple configuration examples are shown in one embodiment, the configuration examples can be combined as appropriate.

[0655] In addition, the content (or even a part of the content) described in one embodiment can be applied to, combined with, or replaced with another content (or even a part of the content) described in that embodiment, and / or the content (or even a part of the content) described in one or more other embodiments.

[0656] The contents described in the embodiments refer to the contents described in each embodiment using various figures or the contents described using text in the specification.

[0657] Furthermore, a figure (or even a part thereof) described in one embodiment can be combined with another part of that figure, another figure (or even a part thereof) described in that embodiment, and / or a figure (or even a part thereof) described in one or more other embodiments to form even more figures.

[0658] In addition, in the present specification and the like, in the block diagrams, components are classified by function and shown as mutually independent blocks. However, in actual circuits, etc., it is difficult to separate components by function, and there may be cases where one circuit is involved in multiple functions, or where one function is involved across multiple circuits. Therefore, the blocks in the block diagrams are not limited to the components described in the specification, but may be rephrased appropriately depending on the situation.

[0659] In addition, in the drawings, the size, layer thickness, or region is shown at an arbitrary size for convenience of explanation. Therefore, it is not necessarily limited to the scale. Note that the drawings are shown schematically for clarity, and are not limited to the shapes or values ​​shown in the drawings. For example, it is possible to include variations in signal, voltage, or current due to noise, or variations in signal, voltage, or current due to timing deviations.

[0660] In this specification and the like, when describing the connection relationship of a transistor, the terms "one of the source or drain" (or first electrode or first terminal) and "the other of the source or drain" (or second electrode or second terminal) are used. This is because the source and drain of a transistor vary depending on the structure or operating conditions of the transistor. Note that the source and drain of a transistor can be appropriately referred to as source (drain) terminal, source (drain) electrode, or the like depending on the situation.

[0661] Furthermore, the terms "electrode" and "wiring" used in this specification and elsewhere do not limit the functionality of these components. For example, an "electrode" may be used as part of a "wiring," and vice versa. Furthermore, the terms "electrode" and "wiring" also include cases where multiple "electrodes" or "wirings" are integrally formed.

[0662] Furthermore, in this specification and the like, the terms voltage and potential can be interchanged as appropriate. Voltage refers to the potential difference from a reference potential. For example, if the reference potential is a ground voltage (earth voltage), then voltage can be interchanged with potential. Ground potential does not necessarily mean 0 V. Note that potential is relative, and the potential applied to wiring, etc. may change depending on the reference potential.

[0663] In this specification and the like, terms such as "film" and "layer" can be interchangeable depending on the circumstances. For example, the term "conductive layer" can be changed to the term "conductive film." Or, for example, the term "insulating film" can be changed to the term "insulating layer."

[0664] In this specification, a switch refers to a device that has a function of controlling whether a current flows by being in a conductive state (on state) or a non-conductive state (off state), or a device that has a function of selecting and switching a path for a current to flow.

[0665] In this specification, the channel length refers to, for example, in a top view of a transistor, a region where a semiconductor (or a portion in the semiconductor through which current flows when the transistor is on) and a gate overlap, or a distance between a source and a drain in a region where a channel is formed.

[0666] In this specification, the channel width refers to, for example, the length of the region where the semiconductor (or the portion in the semiconductor through which current flows when the transistor is on) and the gate electrode overlap, or the length of the portion where the source and drain face each other in the region where the channel is formed.

[0667] In this specification, "A and B are connected" includes not only a direct connection between A and B, but also an electrical connection between A and B. Here, "A and B are electrically connected" means that when an object having some kind of electrical effect exists between A and B, transmission of an electrical signal between A and B is possible.

[0668] In this example, a light-emitting device 1, a light-emitting device 2, and a light-emitting device 3 according to one embodiment of the present invention will be described with reference to FIGS.

[0669] FIG. 22 is a diagram illustrating the configuration of the light-emitting device 550G.

[0670] FIG. 23 is a diagram illustrating the configuration of the light-emitting device 550B.

[0671] FIG. 24 is a diagram illustrating the configuration of the light-emitting device 550R.

[0672] FIG. 25 is a diagram illustrating the current density-luminance characteristics of light-emitting device 1, light-emitting device 2, and light-emitting device 3.

[0673] FIG. 26 is a diagram illustrating the luminance-current efficiency characteristics of light-emitting device 1, light-emitting device 2, and light-emitting device 3.

[0674] FIG. 27 is a diagram illustrating the voltage-luminance characteristics of light-emitting device 1, light-emitting device 2, and light-emitting device 3.

[0675] FIG. 28 is a diagram illustrating the voltage-current characteristics of light-emitting device 1, light-emitting device 2, and light-emitting device 3.

[0676] FIG. 29 shows the light emitting devices 1, 2, and 3 at 1000 cd / m ２ 10 is a diagram illustrating an emission spectrum when light is emitted at a luminance of 1000 .mu.m.

[0677] <Light-Emitting Device 1> The light-emitting device 1 fabricated and described in this example has the same configuration as the light-emitting device 550G (see FIG. 22).

[0678] <Configuration of Light-Emitting Device 1> The configuration of light-emitting device 1 is shown in Table 1. The structural formulas of the materials used in the light-emitting device described in this example are shown below.

[0679]

[0680]

[0681] <<Method of Fabricating Light-Emitting Device 1>> The light-emitting device 1 described in this example was fabricated using a method including the following steps.

[0682] [First Step] In the first step, the reflective film REFG was formed by sputtering using silver (Ag) as a target.

[0683] The reflective film REFG contains Ag and has a thickness of 100 nm.

[0684] [Second Step] In the second step, an electrode 551G was formed on the reflective film REFG. Specifically, the electrode 551G was formed by a sputtering method using an indium oxide-tin oxide (abbreviated as ITSO) target containing silicon or silicon oxide.

[0685] The electrode 551G includes ITSO, has a thickness of 10 nm, and is 4 mm ２ It has an area of ​​(2 mm x 2 mm).

[0686] Next, the substrate on which the electrode 551G was formed was washed with water, baked at 200° C. for 1 hour, and then subjected to UV ozone treatment for 370 seconds. −４ The substrate was introduced into a vacuum deposition apparatus whose internal pressure had been reduced to about Pa, and vacuum baking was performed at 170° C. for 30 minutes in a heating chamber of the vacuum deposition apparatus. Thereafter, the substrate was allowed to cool for about 30 minutes.

[0687] [Third Step] In the third step, a layer 104G was formed on the electrode 551G. Specifically, materials were co-evaporated by using a resistance heating method.

[0688] The layer 104G contains N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) and an electron acceptor material (abbreviation: OCHD-003) in a weight ratio of PCBBiF:OCHD-003 = 1:0.15, and has a thickness of 10 nm. OCHD-003 has acceptor properties and contains fluorine. Its molecular weight is 672.

[0689] [Fourth Step] In the fourth step, a layer 112G-1 was formed on the layer 104G. Specifically, a material was evaporated by using a resistance heating method.

[0690] Note that layer 112G-1 includes PCBBiF and has a thickness of 15 nm.

[0691] [Fifth Step] In the fifth step, a layer 112G-2 was formed on the layer 112G-1. Specifically, a material was evaporated by using a resistance heating method.

[0692] The layer 112G-2 contains 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP) and has a thickness of 20 nm.

[0693] [Sixth Step] In the sixth step, the layer 111G was formed on the layer 112G-2 by co-evaporation of materials using a resistance heating method.

[0694] The layer 111G is made of 8-(1,1′-biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 9-(2-naphthyl)-9′-phenyl-9H,9′H-3,3′-bicarbazole (abbreviation: βNCCP), and [2-(4-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy) ２ (4dppy)) to 8BP-4mDBtPBfpm:βNCCP:Ir(ppy) ２ The composition was 4dppy (4dppy) = 0.6:0.4:0.1 (weight ratio) and had a thickness of 40 nm.

[0695] [Seventh Step] In the seventh step, a layer 113G-1 was formed on the layer 111G. Specifically, a material was evaporated by using a resistance heating method.

[0696] Note that layer 113G-1 contains 8BP-4mDBtPBfpm and has a thickness of 10 nm.

[0697] [Eighth Step] In the eighth step, a layer 113G-2 was formed on the layer 113G-1. Specifically, a material was evaporated by using a resistance heating method.

[0698] The layer 113G-2 contains 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) and has a thickness of 20 nm.

[0699] [Ninth Step] In the ninth step, a layer 105G2 was formed on the layer 113G-2 by vapor deposition using a resistance heating method.

[0700] The layer 105G2 contains lithium oxide (abbreviated as Li2O) and has a thickness of 0.1 nm.

[0701] [Tenth Step] In the tenth step, a layer 106G1 was formed on the layer 105G2. Specifically, a material was evaporated by using a resistance heating method.

[0702] The layer 106G1 contains copper phthalocyanine (abbreviated as CuPc) and has a thickness of 2 nm.

[0703] [Eleventh Step] In the eleventh step, a layer 106G2 was formed on the layer 106G1 by co-evaporation of materials using a resistance heating method.

[0704] The layer 106G2 contains PCBBiF and OCHD-003 in a weight ratio of PCBBiF:OCHD-003=1:0.15, and has a thickness of 10 nm.

[0705] [Twelfth Step] In the twelfth step, a layer 112G2-1 was formed on the layer 106G2. Specifically, a material was evaporated by using a resistance heating method.

[0706] Note that the layer 112G2-1 includes PCBBiF and has a thickness of 20 nm.

[0707] [Thirteenth Step] In the thirteenth step, a layer 112G2-2 was formed on the layer 112G2-1. Specifically, a material was evaporated by using a resistance heating method.

[0708] Note that layer 112G2-2 includes PCBBi1BP and has a thickness of 20 nm.

[0709] [14th Step] In the 14th step, the layer 111G2 was formed on the layer 112G2-2 by co-evaporation of materials using a resistance heating method.

[0710] The layer 111G2 is made of 8BP-4mDBtPBfpm, βNCCP, and Ir(ppy). ２ (4dppy) to 8BP-4mDBtPBfpm:βNCCP:Ir(ppy) ２ The composition was 4dppy (4dppy) = 0.6:0.4:0.1 (weight ratio) and had a thickness of 40 nm.

[0711] [15th Step] In the 15th step, a layer 113G2-1 was formed on the layer 111G2. Specifically, a material was evaporated by using a resistance heating method.

[0712] Note that the layer 113G2-1 contains 8BP-4mDBtPBfpm and has a thickness of 10 nm.

[0713] [16th Step] In the 16th step, a layer 113G2-2 was formed on the layer 113G2-1. Specifically, a material was evaporated by using a resistance heating method.

[0714] The layer 113G2-2 contains NBPhen and has a thickness of 20 nm.

[0715] [Seventeenth Step] In the seventeenth step, a layer 105G was formed on the layer 113G2-2. Specifically, a material was evaporated by using a resistance heating method.

[0716] The layer 105G contains lithium fluoride (abbreviated as LiF) and has a thickness of 1 nm.

[0717] [18th Step] In the 18th step, an electrode 552G was formed on the layer 105G by co-evaporation of materials using a resistance heating method.

[0718] The electrode 552G contains silver (Ag) and magnesium (Mg) at a volume ratio of Ag:Mg=10:1, and has a thickness of 15 nm.

[0719] [19th Step] In the 19th step, a layer CAPG was formed on the electrode 552G. Specifically, a material was evaporated by using a resistance heating method.

[0720] The layer CAPG contains 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II) and has a thickness of 70 nm.

[0721] <Light-Emitting Device 2> The light-emitting device 2 fabricated and described in this example has the same configuration as the light-emitting device 550B (see FIG. 23).

[0722] <Configuration of Light-Emitting Device 2> The configuration of light-emitting device 2 is shown in Table 2. The structural formulas of the materials used in the light-emitting device described in this example are shown below.

[0723]

[0724]

[0725] <<Method of Fabricating Light-Emitting Device 2>> The light-emitting device 2 described in this example was fabricated using a method having the following steps.

[0726] [First Step] In the first step, the reflective film REFB was formed by sputtering using silver (Ag) as a target.

[0727] The reflective film REFB contains Ag and has a thickness of 100 nm.

[0728] [Second Step] In the second step, the electrode 551B was formed on the reflective film REFB. Specifically, the electrode 551B was formed by a sputtering method using an indium oxide-tin oxide (abbreviated as ITSO) target containing silicon or silicon oxide.

[0729] The electrode 551B includes ITSO, has a thickness of 85 nm, and is 4 mm ２ It has an area of ​​(2 mm x 2 mm).

[0730] Next, the substrate on which the electrode 551B was formed was washed with water, baked at 200° C. for 1 hour, and then subjected to UV ozone treatment for 370 seconds. −４ The substrate was introduced into a vacuum deposition apparatus whose internal pressure had been reduced to about Pa, and vacuum baking was performed at 170° C. for 30 minutes in a heating chamber of the vacuum deposition apparatus. Thereafter, the substrate was allowed to cool for about 30 minutes.

[0731] [Third Step] In the third step, a layer 104B was formed on the electrode 551B. Specifically, materials were co-evaporated by using a resistance heating method.

[0732] The layer 104B contains N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf) and OCHD-003 in a weight ratio of BBABnf:OCHD-003=1:0.10, and has a thickness of 10 nm.

[0733] [Fourth Step] In the fourth step, a layer 112B-1 was formed on the layer 104B. Specifically, a material was evaporated by using a resistance heating method.

[0734] The layer 112B-1 contains BBABnf and has a thickness of 25 nm.

[0735] [Fifth Step] In the fifth step, the layer 112B-2 was formed on the layer 112B-1 by vapor deposition of a material using a resistance heating method.

[0736] The layer 112B-2 contains 3,3′-(naphthalene-1,4-diyl)bis(9-phenyl-9H-carbazole (abbreviation: PCzN2)) and has a thickness of 10 nm.

[0737] [Sixth Step] In the sixth step, the layer 111B was formed on the layer 112B-2 by co-evaporation of materials using a resistance heating method.

[0738] The layer 111B contains 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) and 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b′]bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) in a weight ratio of αN-βNPAnth:3,10PCA2Nbf(IV)-02=1:0.015, and has a thickness of 25 nm.

[0739] [Seventh Step] In the seventh step, a layer 113B-1 was formed on the layer 111B. Specifically, materials were co-evaporated by using a resistance heating method.

[0740] The layer 113B-1 contains 2-{4-[9,10-di(naphthalen-2-yl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN) and 8-hydroxyquinolinato-lithium (abbreviation: Liq) in a weight ratio of ZADN:Liq = 1:2, and has a thickness of 10 nm.

[0741] [Eighth Step] In the eighth step, a layer 113B-2 was formed on the layer 113B-1 by vapor deposition of a material using a resistance heating method.

[0742] The layer 113B-2 contains NBPhen and has a thickness of 20 nm.

[0743] [Ninth Step] In the ninth step, a layer 105B2 was formed on the layer 113B-2 by vapor deposition using a resistance heating method.

[0744] The layer 105B2 is Li ２ O and has a thickness of 0.05 nm.

[0745] [Tenth Step] In the tenth step, a layer 106B1 was formed on the layer 105B2 by vapor deposition of a material using a resistance heating method.

[0746] The layer 106B1 contains CuPc and has a thickness of 2 nm.

[0747] [Eleventh Step] In the eleventh step, a layer 106B2 was formed on the layer 106B1 by co-evaporation of materials using a resistance heating method.

[0748] The layer 106B2 contains BBABnf and OCHD-003 in a weight ratio of BBABnf:OCHD-003=1:0.2, and has a thickness of 10 nm.

[0749] [Twelfth Step] In the twelfth step, a layer 112B2-1 was formed on the layer 106B2. Specifically, a material was evaporated by using a resistance heating method.

[0750] The layer 112B2-1 contains BBABnf and has a thickness of 25 nm.

[0751] [Thirteenth Step] In the thirteenth step, the layer 112B2-2 was formed on the layer 112B2-1. Specifically, a material was evaporated by using a resistance heating method.

[0752] The layer 112B2-2 contains PCzN2 and has a thickness of 10 nm.

[0753] [Step 14] In step 14, a layer 111B2 was formed on the layer 112B2-2 by co-evaporation of materials using a resistance heating method.

[0754] The layer 111B2 contains αN-βNPAnth and 3,10PCA2Nbf(IV)-02 in a weight ratio of αN-βNPAnth:3,10PCA2Nbf(IV)-02=1:0.015, and has a thickness of 25 nm.

[0755] [15th Step] In the 15th step, a layer 113B2-1 was formed on the layer 111B2 by co-evaporation of materials using a resistance heating method.

[0756] The layer 113B2-1 contains ZADN and Liq in a weight ratio of ZADN:Liq=1:2 and has a thickness of 10 nm.

[0757] [16th Step] In the 16th step, a layer 113B2-2 was formed on the layer 113B2-1. Specifically, a material was evaporated by using a resistance heating method.

[0758] The layer 113B2-2 contains NBPhen and has a thickness of 30 nm.

[0759] [Seventeenth Step] In the seventeenth step, the layer 105B was formed on the layer 113B2-2. Specifically, a material was evaporated by using a resistance heating method.

[0760] The layer 105B contains LiF and has a thickness of 1 nm.

[0761] [Step 18] In step 18, an electrode 552B was formed on the layer 105B by co-evaporation of materials using a resistance heating method.

[0762] The electrode 552B contains Ag and Mg at a volume ratio of Ag:Mg=1:0.1 and has a thickness of 15 nm.

[0763] [Step 19] In step 19, a layer CAPB was formed on the electrode 552B. Specifically, a material was evaporated by using a resistance heating method.

[0764] The layer CAPB includes DBT3P-II and has a thickness of 80 nm.

[0765] <Light-Emitting Device 3> The light-emitting device 3 fabricated and described in this example has the same configuration as the light-emitting device 550R (see FIG. 24).

[0766] <Configuration of Light-Emitting Device 3> The configuration of light-emitting device 3 is shown in Table 3. The structural formulas of the materials used in the light-emitting device described in this example are shown below.

[0767]

[0768]

[0769] <<Method of Fabricating Light-Emitting Device 3>> The light-emitting device 3 described in this example was fabricated using a method having the following steps.

[0770] [First Step] In the first step, the reflective film REFR was formed by sputtering using silver (Ag) as a target.

[0771] The reflective film REFR contains Ag and has a thickness of 100 nm.

[0772] [Second Step] In the second step, an electrode 551R was formed on the reflective film REFR. Specifically, the electrode 551R was formed by a sputtering method using an indium oxide-tin oxide (abbreviation: ITSO) target containing silicon or silicon oxide.

[0773] The electrode 551R includes ITSO, has a thickness of 10 nm, and is 4 mm ２ It has an area of ​​(2 mm x 2 mm).

[0774] Next, the substrate on which the electrode 551R was formed was washed with water, baked at 200° C. for 1 hour, and then subjected to UV ozone treatment for 370 seconds. −４ The substrate was introduced into a vacuum deposition apparatus whose internal pressure had been reduced to about Pa, and vacuum baking was performed at 170° C. for 30 minutes in a heating chamber of the vacuum deposition apparatus. Thereafter, the substrate was allowed to cool for about 30 minutes.

[0775] [Third Step] In the third step, a layer 104R was formed on the electrode 551R. Specifically, materials were co-evaporated using a resistance heating method.

[0776] The layer 104R contains PCBBiF and OCHD-003 in a weight ratio of PCBBiF:OCHD-003=1:0.15, and has a thickness of 10 nm.

[0777] [Fourth Step] In the fourth step, a layer 112R was formed on the layer 104R. Specifically, a material was evaporated by using a resistance heating method.

[0778] Note that layer 112R includes PCBBiF and has a thickness of 70 nm.

[0779] [Fifth Step] In the fifth step, the layer 111R was formed on the layer 112R. Specifically, materials were co-evaporated using a resistance heating method.

[0780] The layer 111R contains 9-[(3′-dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), PCBBiF, and a phosphorescent material (abbreviation: OCPG-006) in a weight ratio of 9mDBtBPNfpr:PCBBiF:OCPG-006=0.6:0.4:0.05, and has a thickness of 50 nm.

[0781] [Sixth Step] In the sixth step, a layer 113R-1 was formed on the layer 111R. Specifically, a material was evaporated by using a resistance heating method.

[0782] The layer 113R-1 contains 9mDBtBPNfpr and has a thickness of 10 nm.

[0783] [Seventh Step] In the seventh step, a layer 113R-2 was formed on the layer 113R-1 by vapor deposition of a material using a resistance heating method.

[0784] The layer 113R-2 contains NBPhen and has a thickness of 20 nm.

[0785] [Eighth Step] In the eighth step, a layer 105R2 was formed on the layer 113R-2 by vapor deposition using a resistance heating method.

[0786] The layer 105R2 is Li ２ O and has a thickness of 0.1 nm.

[0787] [Ninth Step] In the ninth step, a layer 106R1 was formed on the layer 105R2 by evaporating a material using a resistance heating method.

[0788] The layer 106R1 contains CuPC and has a thickness of 2 nm.

[0789] [Tenth Step] In the tenth step, a layer 106R2 was formed on the layer 106R1 by co-evaporation of materials using a resistance heating method.

[0790] The layer 106R2 contains PCBBiF and OCHD-003 in a weight ratio of PCBBiF:OCHD-003=1:0.15, and has a thickness of 10 nm.

[0791] [Eleventh Step] In the eleventh step, a layer 112R2 was formed on the layer 106R2. Specifically, a material was evaporated by using a resistance heating method.

[0792] Note that layer 112R2 includes PCBBiF and has a thickness of 40 nm.

[0793] [Twelfth Step] In the twelfth step, a layer 111R2 was formed on the layer 112R2 by co-evaporation of materials using a resistance heating method.

[0794] The layer 111R2 contains 9mDBtBPNfpr, PCBBiF, and OCPG-006 in a weight ratio of 9mDBtBPNfpr:PCBBiF:OCPG-006=0.6:0.4:0.05, and has a thickness of 50 nm.

[0795] [Thirteenth Step] In the thirteenth step, a layer 113R2-1 was formed on the layer 111R2. Specifically, a material was evaporated by using a resistance heating method.

[0796] The layer 113R2-1 contains 9mDBtBPNfpr and has a thickness of 20 nm.

[0797] [14th Step] In the 14th step, a layer 113R2-2 was formed on the layer 113R2-1. Specifically, a material was evaporated by using a resistance heating method.

[0798] The layer 113R2-2 contains NBPhen and has a thickness of 20 nm.

[0799] [15th Step] In the 15th step, the layer 105R-1 was formed on the layer 113R2-2 by evaporating a material using a resistance heating method.

[0800] The layer 105R-1 contains LiF and has a thickness of 1 nm.

[0801] [16th Step] In the 16th step, a layer 105R-2 was formed on the layer 105R-1 by evaporating a material using a resistance heating method.

[0802] The layer 105R-2 contains Yb and has a thickness of 0.8 nm.

[0803] [Seventeenth Step] In the seventeenth step, the electrode 552R was formed on the layer 105R-2 by co-evaporation of materials using a resistance heating method.

[0804] The electrode 552R contains Ag and Mg at a volume ratio of Ag:Mg, and has a thickness of 15 nm.

[0805] [18th Step] In the 18th step, a layer CAPR was formed on the electrode 552R. Specifically, a material was evaporated by using a resistance heating method.

[0806] The layer CAPR includes DBT3P-II and has a thickness of 70 nm.

[0807] <<Operation Characteristics of Light-Emitting Device 1, Light-Emitting Device 2, and Light-Emitting Device 3>> When power was supplied, light-emitting device 1 emitted light ELG and light ELG2 (see FIG. 22). Light-emitting device 2 emitted light ELB and light ELB2 (see FIG. 23). Light-emitting device 3 emitted light ELR and light ELR2 (see FIG. 24). The operation characteristics of light-emitting devices 1, 2, and 3 were measured at room temperature (see FIGS. 25 to 29). A spectroradiometer (SR-UL1R, manufactured by Topcon Corporation) was used to measure the luminance, CIE chromaticity, and emission spectrum.

[0808] The fabricated light-emitting device had a brightness of 1000 cd / m ２ The main initial characteristics when light was emitted at about this temperature are shown in Table 4. Table 4 also lists the characteristics of other light-emitting devices, the configurations of which will be described later.

[0809]

[0810] It was found that the light emitting devices 1, 2 and 3 exhibited good characteristics.

[0811] In this example, a light-emitting device 4 and a light-emitting device 5 according to one embodiment of the present invention will be described with reference to FIGS.

[0812] FIG. 30 is a diagram illustrating the configuration of a light-emitting device 550G.

[0813] FIG. 31 is a diagram illustrating the configuration of a light-emitting device 550G.

[0814] FIG. 32 is a diagram illustrating the current density-luminance characteristics of the light-emitting device 4 and the light-emitting device 5. In FIG.

[0815] FIG. 33 is a diagram illustrating the luminance-current efficiency characteristics of the light-emitting device 4 and the light-emitting device 5. In FIG.

[0816] FIG. 34 is a diagram illustrating the voltage-luminance characteristics of the light-emitting device 4 and the light-emitting device 5. In FIG.

[0817] FIG. 35 is a diagram illustrating the voltage-current characteristics of the light-emitting device 4 and the light-emitting device 5. In FIG.

[0818] FIG. 36 shows the light emitting device 4 and the light emitting device 5 at 1000 cd / m ２ 10 is a diagram illustrating an emission spectrum when light is emitted at a luminance of 1000 .mu.m.

[0819] <Light-Emitting Device 4, Light-Emitting Device 5> The light-emitting device 4 and light-emitting device 5 fabricated in this example have the same configuration as the light-emitting device 550G (see FIG. 30).

[0820] <Configurations of Light-Emitting Device 4 and Light-Emitting Device 5> The configurations of light-emitting device 4 and light-emitting device 5 are shown in Table 5. The structural formulas of the materials used in the light-emitting devices described in this example are shown below.

[0821]

[0822]

[0823] <<Method of Fabricating Light-Emitting Device 4>> The light-emitting device 4 described in this example was fabricated using a method having the following steps....

Claims

1. a first light emitting device; and a second light emitting device; the second light emitting device is adjacent to the first light emitting device; the first light emitting device comprises a first electrode, a second electrode, a first unit, a second unit, a first intermediate layer, and a first layer; the first unit is sandwiched between the second electrode and the first electrode; the second unit is sandwiched between the second electrode and the first unit; the first intermediate layer is sandwiched between the second unit and the first unit; the first layer is sandwiched between the first intermediate layer and the first unit; the first unit has a function of emitting a first light, the second unit has a function of emitting a second light, the first intermediate layer has a function of supplying holes to the second unit, the first intermediate layer has a function of supplying electrons to the first layer, the first layer comprises an unpaired electron; The unpaired electrons were measured using an electron spin resonance apparatus at 1×10 １６ spins / cm ３ Above 1 x 10 １８ spins / cm ３ It can be observed at the following spin densities: the first layer comprises a first inorganic compound and a first organic compound; The first organic compound has an unshared electron pair, the first organic compound interacts with the first inorganic compound to form a half-occupied orbital; the second light emitting device comprises a third electrode, a fourth electrode, a third unit, a fourth unit, a second intermediate layer and a second layer; the third unit is sandwiched between the fourth electrode and the third electrode; the fourth unit is sandwiched between the fourth electrode and the third unit; the second intermediate layer is sandwiched between the fourth unit and the third unit; the second layer is sandwiched between the second intermediate layer and the third unit; the third unit has a function of emitting a third light, the fourth unit has a function of emitting a fourth light, the second intermediate layer has a function of supplying holes to the fourth unit, the second intermediate layer has a function of supplying electrons to the second layer, the second intermediate layer has a first gap between it and the first intermediate layer; the second layer has a second gap between it and the first layer; The second layer includes the first inorganic compound and the first organic compound.

2. In claim 1, the first light emitting device comprises a third layer; the third layer is sandwiched between the first unit and the first electrode; the second light emitting device comprises a fourth layer; the fourth layer is sandwiched between the third unit and the third electrode; The fourth layer has a third gap between it and the third layer.

3. In claim 2, The third layer is 1×10 ２ Ω・cm or more 1×10 ８ A display device having an electrical resistivity of Ω·cm or less.

4. In any one of claims 1 to 3, The display device, wherein the unpaired electron has a g value in the range of 2.003 or more and 2.004 or less.

5. In any one of claims 1 to 4, The unpaired electrons can be observed in the atmosphere after 24 hours at a spin density of 50% or more of the initial value using an electron spin resonance apparatus.

6. In any one of claims 1 to 5, The display device, wherein the first organic compound has a π-electron deficient heteroaromatic ring.

7. In any one of claims 1 to 6, The display device, wherein the LUMO level of the first organic compound is in the range of −3.6 eV to −2.3 eV.

8. In any one of claims 1 to 7, The display device, wherein the first inorganic compound contains a metal element and oxygen.

9. In any one of claims 1 to 7, The display device, wherein the first inorganic compound contains lithium and oxygen.

10. In any one of claims 1 to 9, The first intermediate layer has unpaired electrons.

11. In any one of claims 1 to 10, the first intermediate layer includes a second organic compound and a third organic compound; the second organic compound has at least one of an electron-rich heteroaromatic ring or an aromatic amine; the HOMO level of the second organic compound is in the range of −5.7 eV to −5.3 eV, the third organic compound has fluorine; the LUMO level of the third organic compound is −5.0 eV or less; The third organic compound has an electron accepting property with respect to the second organic compound.

12. In claim 11, The display device, wherein the third organic compound has a cyano group.

13. In any one of claims 1 to 12, The display device, wherein the first intermediate layer does not contain a metal element.

14. In any one of claims 1 to 13, the first intermediate layer has a fifth layer and a sixth layer; the fifth layer is sandwiched between the first layer and the sixth layer; the fifth layer includes a fourth organic compound; The display device, wherein the LUMO level of the fourth organic compound is in the range of −4.0 eV to −3.3 eV.

15. In any one of claims 1 to 14, A first functional layer; A second functional layer; a display area; the first functional layer includes a driving circuit; the driving circuit generates a first image signal and a second image signal; the second functional layer overlaps the first functional layer; the second functional layer includes a first pixel circuit and a second pixel circuit; the first pixel circuit is supplied with the first image signal; the second pixel circuit is supplied with the second image signal; the display area comprises a set of pixels; the set of pixels includes a first pixel and a second pixel; the first pixel comprises the first light emitting device and the first pixel circuit; the first light emitting device is electrically connected to the first pixel circuit; the second pixel comprises the second light emitting device and the second pixel circuit; The second light emitting device is electrically connected to the second pixel circuit.

16. A display device comprising: a display unit according to any one of claims 1 to 15; and a calculation unit; The calculation unit generates image information, The display device is an electronic device that displays the image information.

17. A display device comprising the display device according to claim 15 and a calculation unit, the first functional layer includes the calculation unit, The calculation unit generates image information, The display device is an electronic device that displays the image information.