Indication device

Abstract

To provide a novel display device that is superior in convenience, usefulness, or reliability. [Solution] A display device comprising a first light-emitting device, a second light-emitting device, an insulating film, a conductive film, a first reflective film, and a second reflective film, wherein the first light-emitting device comprises a first electrode, a second electrode, and a first unit, the first electrode being sandwiched between the first unit and the insulating film. The second light-emitting device comprises a third electrode, a fourth electrode, and a second unit, the third electrode being sandwiched between the second unit and the insulating film, and the third electrode having a first gap between itself and the first electrode. The first gap is sandwiched between the conductive film and the insulating film. The first reflective film is sandwiched between the first electrode and the insulating film and has a first distance DR between itself and the second electrode, and the second reflective film is sandwiched between the third electrode and the insulating film and has a second distance DG between itself and the fourth electrode. The second distance DG is longer than the first distance DR.

Description

[Technical Field]

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

[0002] Furthermore, one aspect of the present invention is not limited to the above-mentioned technical field. The technical field of one aspect of the invention disclosed herein relates to a product, method, or method of manufacture. Alternatively, one aspect of the present invention relates to a process, machine, manufacture, or composition of matter. More specifically, examples of the technical field of one aspect of the present invention disclosed herein include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, methods for driving them, or methods for manufacturing them. [Background technology]

[0003] The practical application of light-emitting devices (organic electroluminescent devices) that utilize electroluminescence (EL) using organic compounds is progressing. The basic structure of these light-emitting devices is an organic compound layer (EL layer) containing a light-emitting material sandwiched between a pair of electrodes. By applying a voltage to this device, carriers (holes and electrons) are injected, and by utilizing the recombination energy of these carriers, light emission can be obtained from the light-emitting material.

[0004] Because these light-emitting devices are self-emissive, using them as pixels in a display offers advantages over liquid crystal displays, such as higher visibility and the elimination of the need for a backlight, making them suitable as flat-panel display elements. Furthermore, displays using such light-emitting devices can be manufactured to be thin and lightweight, which is a significant advantage. Another characteristic is their extremely fast response speed.

[0005] Furthermore, since these light-emitting devices can form a light-emitting layer continuously in two dimensions, they can produce light in a planar manner. This is a feature that is difficult to obtain with point light sources such as incandescent bulbs or LEDs, or line light sources such as fluorescent lamps, and therefore has high value as a planar light source that can be applied to lighting and other applications.

[0006] While displays or lighting devices using light-emitting devices are suitable for various electronic devices, research and development are underway to find light-emitting devices with even better characteristics.

[0007] A light-emitting device that emits light having multiple emission colors is known, wherein the light-emitting device comprises a first light-emitting element and a second light-emitting element, the first light-emitting element comprises a first lower electrode, a first light-emitting layer on the first lower electrode, a second light-emitting layer on the first light-emitting layer, and an upper electrode on the second light-emitting layer, the second light-emitting element comprises a second lower electrode, a first light-emitting layer on the second lower electrode, a second light-emitting layer on the first light-emitting layer, and an upper electrode on the second light-emitting layer, the first light-emitting layer having a peak in its emission spectrum on the longer wavelength side than the second light-emitting layer, and the distance between the first lower electrode and the first light-emitting layer being shorter than the distance between the second lower electrode and the first light-emitting layer (Patent Document 1).

[0008] Furthermore, organic EL devices may be used in the display units of AR or VR display devices or HMDs. As one example of an organic EL device, Non-Patent Document 1 discloses a method for manufacturing an organic optoelectronic device using standard UV photolithography. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2016-85968 [Non-patent literature]

[0010] [Non-Patent Document 1] B. Lamprecht et al., “Organic optoelectronic device fabrication using standard UV photolithography” phys.stat.sol.(RRL)2, No.1, pp.16-18 (2008) [Overview of the project] [Problems that the invention aims to solve]

[0011] One aspect of the present invention aims to provide a novel display device that is superior in convenience, usefulness, or reliability. Alternatively, it aims to provide a novel electronic device that is superior in convenience, usefulness, or reliability. Alternatively, it aims to provide a novel display device, a novel electronic device, or a novel semiconductor device.

[0012] Furthermore, the description of these problems does not preclude the existence of other problems. Moreover, one aspect of the present invention does not need to solve all of these problems. Other problems will naturally become apparent from the description in the specification, drawings, and claims, and it is possible to extract other problems from the description in the specification, drawings, and claims. [Means for solving the problem]

[0013] (1) One aspect of the present invention is a display device having a first light-emitting device, a second light-emitting device, an insulating film, a conductive film, a first reflective film, and a second reflective film.

[0014] The first light-emitting device comprises a first electrode, a second electrode, and a first unit. The first unit is sandwiched between the first electrode and the second electrode, and the first electrode is sandwiched between the first unit and an insulating film.

[0015] The second light-emitting device comprises a third electrode, a fourth electrode, and a second unit. The second unit is sandwiched between the third and fourth electrodes, and the third electrode is sandwiched between the second unit and an insulating film. The third electrode also has a first gap between it and the first electrode.

[0016] The conductive film electrically connects the second and fourth electrodes, and the first gap is sandwiched between the conductive film and the insulating film.

[0017] The first reflective film is sandwiched between the first electrode and the insulating film, and the first reflective film has a first distance DR between it and the second electrode.

[0018] The second reflective film is sandwiched between the third electrode and the insulating film, and the second reflective film has a second distance DG between it and the fourth electrode.

[0019] The second distance DG is in a relationship with the first distance DR that satisfies the following equations (1) to (3).

[0020]

number

[0021] (2) One aspect of the present invention is a display device in which the second unit has the function of emitting a first light, and the first light has the maximum peak of its emission spectrum in the range of 480 nm to 600 nm.

[0022] This makes it possible to reduce the step difference between the first and second light-emitting devices. It also reduces the step difference in the conductive film. Furthermore, it suppresses the phenomenon of cuts or tears occurring in the conductive film along the step difference. In addition, green light can be used for display. As a result, a novel display device with superior convenience, usefulness, and reliability can be provided.

[0023] (3) One aspect of the present invention is the above-mentioned display device having a filler.

[0024] The filler is sandwiched between the first electrode and the third electrode, and between the insulating film and the conductive film. Additionally, the filler is sandwiched between the first unit and the second unit.

[0025] This allows the second light-emitting device to be separated from the first light-emitting device. Furthermore, the gap formed between the first and second light-emitting devices can be filled with a filler material. Additionally, the step resulting from the gap between the first and second light-emitting devices can be reduced. Furthermore, the step resulting in the conductive film can be reduced. Moreover, the phenomenon of cuts or tears forming in the conductive film along the step can be suppressed. As a result, a novel display device with superior convenience, usefulness, and reliability can be provided.

[0026] (4) One aspect of the present invention is the above-described display device having a third light-emitting device and a third reflective film.

[0027] The third light-emitting device comprises a fifth electrode, a sixth electrode, and a third unit. The third unit is sandwiched between the fifth and sixth electrodes, and the fifth electrode is sandwiched between the third unit and an insulating film. The fifth electrode also has a second gap between it and the third electrode.

[0028] The conductive film electrically connects the fourth and sixth electrodes, and the second gap is sandwiched between the conductive film and the insulating film.

[0029] The third reflective film is sandwiched between the fifth electrode and the insulating film, and the third reflective film has a third distance DB between it and the sixth electrode.

[0030] The third distance DB is related to the first distance DR and the second distance DG in a way that satisfies the following equations (1) to (3).

[0031]

number

[0032] (5) One aspect of the present invention is the above-mentioned display device, wherein the third distance DB is 200 nm or less.

[0033] This makes it possible to reduce the step difference between the first and second light-emitting devices. It also makes it possible to reduce the step difference between the second and third light-emitting devices. Furthermore, it makes it possible to reduce the step difference in the conductive film. Additionally, it suppresses the phenomenon of cuts or tears occurring in the conductive film along the step. As a result, it is possible to provide a novel optical functional device with superior convenience, usefulness, and reliability.

[0034] (6) One aspect of the present invention is the above-described display device having a third light-emitting device and a third reflective film.

[0035] The third light-emitting device comprises a fifth electrode, a sixth electrode, and a third unit. The third unit is sandwiched between the fifth and sixth electrodes, and the fifth electrode is sandwiched between the third unit and an insulating film. The fifth electrode also has a second gap between it and the third electrode.

[0036] The conductive film electrically connects the fourth and sixth electrodes, and the second gap is sandwiched between the conductive film and the insulating film.

[0037] The third reflective film is sandwiched between the fifth electrode and the insulating film, and the third reflective film has a third distance DB between it and the sixth electrode.

[0038] The third distance DB is related to the first distance DR and the second distance DG in a way that satisfies the following equations (1) to (3).

[0039]

number

[0040] (7) One aspect of the present invention is the above-described display device, wherein the first distance DR is 150 nm or less.

[0041] This makes it possible to reduce the step difference between the first and second light-emitting devices. It also makes it possible to reduce the step difference between the second and third light-emitting devices. Furthermore, it makes it possible to reduce the step difference in the conductive film. Additionally, it suppresses the phenomenon of cuts or tears occurring in the conductive film along the step. As a result, it is possible to provide a novel optical functional device with superior convenience, usefulness, and reliability.

[0042] (8) One aspect of the present invention is the above-described display device, wherein a first unit has the function of emitting a second light, the second light having a wavelength of 600 nm to 740 nm, and a third unit has the function of emitting a third light, the third light having a wavelength of 400 nm to 480 nm.

[0043] This makes it possible to reduce the step difference between the first and third light-emitting devices. It also reduces the step difference in the conductive film. Furthermore, it suppresses the phenomenon of cuts or tears occurring in the conductive film along the step difference. In addition, red light can be used for display. In addition, blue light can be used for display. As a result, a novel display device with superior convenience, usefulness, and reliability can be provided.

[0044] (9) One aspect of the present invention is the above-described display device, wherein the first light-emitting device comprises a first layer and the second light-emitting device comprises a second layer.

[0045] The first layer is sandwiched between the first unit and the first electrode, and the first layer contains an electron-accepting substance and a hole-transporting material. The first layer is 1 × 10 2 [Ω cm] or more 1×10 8It has an electrical resistivity of [Ω·cm] or less.

[0046] The second layer is sandwiched between the second unit and the third electrode, and the second layer has a third gap between it and the first layer. The second layer also contains an electron-accepting material and a hole-transporting material.

[0047] This makes it possible to suppress the current flowing between the first and second layers. Furthermore, it is possible to suppress the crosstalk phenomenon occurring between the first and second light-emitting devices. As a result, a novel display device with superior convenience, usefulness, and reliability can be provided.

[0048] (10) One aspect of the present invention is a display device having a display area, a first functional layer, and a second functional layer.

[0049] The display area comprises a set of pixels, and the set of pixels includes a first pixel and a second pixel.

[0050] The first pixel comprises 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 first pixel circuit being supplied with a first image signal.

[0051] The second pixel comprises a second light-emitting device and a second pixel circuit, the second light-emitting device being electrically connected to the second pixel circuit, and the second pixel circuit being supplied with a second image signal.

[0052] The first functional layer includes a first pixel circuit and a second pixel circuit. The first functional layer is sandwiched between a first light-emitting device and a second functional layer, and the first functional layer is sandwiched between a second light-emitting device and a second functional layer.

[0053] The second functional layer includes a drive circuit, which generates a first image signal and a second image signal.

[0054] This allows the drive circuit to be placed on top of the first and second pixel circuits. Furthermore, the area outside the display region for image information can be reduced. The distance between the first pixel circuit and the drive circuit can also be shortened. Additionally, image signals can be transmitted without delay. As a result, a novel display device with superior convenience, usefulness, and reliability can be provided.

[0055] (11) One aspect of the present invention is an electronic device having a calculation unit and the above-mentioned display device. The calculation unit generates image information, and the display device displays the image information.

[0056] (12) One aspect of the present invention is an electronic device having a calculation unit and the above-mentioned display device. The second functional layer includes a calculation unit, the calculation unit generates image information, and the display device displays the image information. [Effects of the Invention]

[0057] According to one aspect of the present invention, a novel display device with superior convenience, usefulness, or reliability can be provided. Alternatively, a novel electronic device with superior convenience, usefulness, or reliability can be provided. Alternatively, a novel display device, a novel electronic device, or a novel semiconductor device can be provided.

[0058] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one aspect of the present invention does not necessarily have to possess all of these effects. Other effects will naturally become apparent from the description in the specification, drawings, and claims, and it is possible to extract other effects from the description in the specification, drawings, and claims. [Brief explanation of the drawing]

[0059] [Figure 1] Figure 1 is a diagram illustrating the configuration of a display device according to an embodiment. [Figure 2] Figure 2 is a diagram illustrating the configuration of a display device according to an embodiment. [Figure 3]Figure 3 is a diagram illustrating the configuration of a display device according to an embodiment. [Figure 4] Figures 4A and 4B illustrate the configuration of a light-emitting device according to an embodiment. [Figure 5] Figures 5A and 5B illustrate the configuration of a display device according to an embodiment. [Figure 6] Figures 6A and 6B are cross-sectional views illustrating the configuration of a display device according to an embodiment. [Figure 7] Figure 7 is a circuit diagram illustrating the pixels of a display device according to an embodiment. [Figure 8] Figure 8 is a diagram illustrating the configuration of a display device according to an embodiment. [Figure 9] Figure 9 is a diagram illustrating the configuration of a display device according to an embodiment. [Figure 10] Figure 10 is a diagram illustrating the configuration of a display device according to an embodiment. [Figure 11] Figures 11A and 11B illustrate the configuration of a display device according to an embodiment. [Figure 12] Figure 12 is a diagram illustrating the configuration of a display device according to an embodiment. [Figure 13] Figures 13A and 13B illustrate the configuration of a display device according to an embodiment. [Figure 14] Figure 14 is a diagram illustrating the configuration of a display device according to an embodiment. [Figure 15] Figure 15 is a diagram illustrating the configuration of a display device according to an embodiment. [Figure 16] Figure 16 is a diagram illustrating the configuration of a display device according to an embodiment. [Figure 17] Figure 17 is a diagram illustrating the configuration of a display device according to an embodiment. [Figure 18] Figure 18 is a diagram illustrating the configuration of a display device according to an embodiment. [Figure 19] Figures 19A to 19C illustrate the configuration of a transistor according to an embodiment. [Figure 20]Figures 20A to 20C illustrate a metal oxide according to an embodiment. [Figure 21] Figures 21A to 21D illustrate the electronic device according to an embodiment. [Figure 22] Figures 22A and 22B illustrate the electronic device according to the embodiment. [Figure 23] Figures 23A and 23B illustrate the configuration of a light-emitting device according to an embodiment. [Figure 24] Figure 24 illustrates the current density-luminance characteristics of the light-emitting device according to the embodiment. [Figure 25] Figure 25 illustrates the brightness-current efficiency characteristics of the light-emitting device according to the embodiment. [Figure 26] Figure 26 illustrates the voltage-luminance characteristics of the light-emitting device according to the embodiment. [Figure 27] Figure 27 illustrates the voltage-current characteristics of the light-emitting device according to the embodiment. [Figure 28] Figure 28 illustrates the emission spectrum of the light-emitting device according to the embodiment. [Figure 29] Figure 29 illustrates the current density-luminance characteristics of the light-emitting device according to the embodiment. [Figure 30] Figure 30 illustrates the brightness-current efficiency characteristics of the light-emitting device according to the embodiment. [Figure 31] Figure 31 is a diagram illustrating the voltage-luminance characteristics of the light-emitting device according to the embodiment. [Figure 32] Figure 32 illustrates the voltage-current characteristics of the light-emitting device according to the embodiment. [Figure 33] Figure 33 illustrates the emission spectrum of the light-emitting device according to the embodiment. [Figure 34] Figure 34 illustrates the current density-luminance characteristics of the light-emitting device according to the embodiment. [Figure 35] Figure 35 illustrates the brightness-current efficiency characteristics of the light-emitting device according to the embodiment. [Figure 36]Figure 36 illustrates the voltage-luminance characteristics of the light-emitting device according to the embodiment. [Figure 37] Figure 37 illustrates the voltage-current characteristics of the light-emitting device according to the embodiment. [Figure 38] Figure 38 illustrates the luminance-blue index characteristics of the light-emitting device according to the embodiment. [Figure 39] Figure 39 is a diagram illustrating the emission spectrum of the light-emitting device according to the embodiment. [Figure 40] Figures 40A to 40D illustrate the configuration of the light-emitting device 5 according to the embodiment. [Figure 41] Figure 41 is a diagram illustrating the current density-luminance characteristics of the light-emitting device 5 according to the embodiment. [Figure 42] Figure 42 is a diagram illustrating the brightness-current efficiency characteristics of the light-emitting device 5 according to the embodiment. [Figure 43] Figure 43 is a diagram illustrating the voltage-luminance characteristics of the light-emitting device 5 according to the embodiment. [Figure 44] Figure 44 is a diagram illustrating the voltage-current characteristics of the light-emitting device 5 according to the embodiment. [Figure 45] Figure 45 is a diagram illustrating the emission spectrum of the light-emitting device 5 according to the embodiment. [Figure 46] Figure 46 illustrates the change in normalized brightness over time for the light-emitting device 5 according to the embodiment. [Modes for carrying out the invention]

[0060] A display device according to one aspect of the present invention comprises a first light-emitting device, a second light-emitting device, an insulating film, a conductive film, a first reflective film, and a second reflective film. The first light-emitting device comprises a first electrode, a second electrode, and a first unit, the first unit being sandwiched between the second electrode and the first electrode, and the first electrode being sandwiched between the first unit and the insulating film. The second light-emitting device comprises a third electrode, a fourth electrode, and a second unit, the second unit being sandwiched between the fourth electrode and the third electrode, the third electrode being sandwiched between the second unit and the insulating film, and the third electrode having a first gap between itself and the first electrode. The conductive film electrically connects the second electrode and the fourth electrode, and the first gap is sandwiched between the conductive film and the insulating film. The first reflective film is sandwiched between the first electrode and the insulating film and has a first distance DR between itself and the second electrode. The second reflective film is sandwiched between the third electrode and the insulating film, and has a second distance DG between it and the fourth electrode. The second distance DG is longer than the first distance DR, and the difference is greater than 20 nm and less than 85 nm.

[0061] This makes it possible to reduce the step difference between the first and second light-emitting devices. It also makes it possible to reduce the step difference in the conductive film. Furthermore, it is possible to suppress the phenomenon of cuts or tears occurring in the conductive film along the step. As a result, it is possible to provide a novel display device with superior convenience, usefulness, and reliability.

[0062] Embodiments will be described in detail with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be interpreted as being limited to the contents of the embodiments shown below. In the configuration of the invention described below, the same reference numerals are used in common across different drawings for the same parts or parts having similar functions, and repeated descriptions are omitted.

[0063] (Embodiment 1) In this embodiment, the configuration of a display device 700 according to one aspect of the present invention will be described with reference to Figures 1 to 3.

[0064] Figure 1 is a cross-sectional view illustrating the configuration of a display device according to one embodiment of the present invention.

[0065] Figure 2 is a cross-sectional view illustrating the configuration of a display device according to one embodiment of the present invention.

[0066] Figure 3 is a cross-sectional view illustrating the configuration of a display device according to one embodiment of the present invention.

[0067] <Example of display device configuration 1> The display device 700 described in this embodiment includes a light-emitting device 550R(i,j), a light-emitting device 550G(i,j), an insulating film 521, a conductive film 552, a reflective film REFR(i,j), and a reflective film REGF(i,j) (see Figure 1).

[0068] <Example configuration of light-emitting device 550R(i,j) 1> The light-emitting device 550R(i,j) comprises electrode 551R(i,j), electrode 552R(i,j), and unit 103R(i,j).

[0069] Unit 103R(i,j) is sandwiched between electrodes 552R(i,j) and 551R(i,j), and electrode 551R(i,j) is sandwiched between unit 103R(i,j) and the insulating film 521.

[0070] <Example Configuration 1 of Light-Emitting Device 550G(i,j)> The light-emitting device 550G(i,j) comprises electrode 551G(i,j), electrode 552G(i,j), and unit 103G(i,j).

[0071] Unit 103G(i,j) is sandwiched between electrodes 552G(i,j) and 551G(i,j), and electrode 551G(i,j) is sandwiched between unit 103G(i,j) and insulating film 521.

[0072] 《Example configuration of electrode 551G(i,j)》 Electrode 551G(i,j) has a gap 551RG(i,j) between it and electrode 551R(i,j).

[0073] <Example 1 of the composition of conductive film 552> The conductive film 552 electrically connects electrodes 552R(i,j) and 552G(i,j). Note that one conductive film can be used for the conductive film 552, electrodes 552R(i,j), and electrodes 552G(i,j). In this case, the region of the conductive film that overlaps with electrode 551R(i,j) can be used for electrode 552R(i,j), the region that overlaps with electrode 551G(i,j) can be used for electrode 552G(i,j), and the area between electrodes 552R(i,j) and 552G(i,j) of the conductive film can be used for conductive film 552.

[0074] The gap 551RG(i,j) is sandwiched between the conductive film 552 and the insulating film 521.

[0075] <Example of reflective film REFR(i,j) configuration> The reflective film REFR(i,j) is sandwiched between the electrode 551R(i,j) and the insulating film 521. Furthermore, the reflective film REFR(i,j) has a distance DR between it and the electrode 552R(i,j).

[0076] <Example of reflective film REGF(i,j) configuration> The reflective film REFG(i,j) is sandwiched between the electrode 551G(i,j) and the insulating film 521. Furthermore, the reflective film REFG(i,j) has a distance DG between it and the electrode 552G(i,j).

[0077] Distance DG is in a relationship with distance DR that satisfies all of the following equations (1) to (3). In other words, distance DR is longer than distance DG, and the difference is greater than 20 nm and less than 85 nm. More preferably, distance DR is longer than distance DG, and the difference is greater than 20 nm and less than 40 nm.

[0078]

number

[0079] 《Example configuration of Unit 103G(i,j)》 Unit 103G(i,j) is equipped with the function of emitting photo-ELG. The photo-ELG also has the maximum peak of its emission spectrum in the range of 480 nm to 600 nm.

[0080] This makes it possible to reduce the step difference between the light-emitting device 550R(i,j) and the light-emitting device 550G(i,j). It also makes it possible to reduce the step difference in the conductive film 552. Furthermore, it is possible to suppress the phenomenon of cuts or tears occurring in the conductive film 552 along the step difference. In addition, green light can be used for display. As a result, a novel display device with superior convenience, usefulness, and reliability can be provided.

[0081] <Example of display device configuration 2> The display device 700 described in this embodiment has a filler material 529RG(i,j) (see Figure 1).

[0082] <Example 1 of the composition of filler material 529RG(i,j)> The filler material 529RG(i,j) is sandwiched between electrodes 551R(i,j) and 551G(i,j). In other words, the filler material 529RG is in the gap 551RG, for example, filling the gap 551RG.

[0083] Furthermore, the filler material 529RG(i,j) is sandwiched between the insulating film 521 and the conductive film 552. For example, the filler material 529RG fills the space between the insulating film 521 and the conductive film 552.

[0084] Furthermore, the filler material 529RG(i,j) is sandwiched between units 103R(i,j) and 103G(i,j). For example, filler material 529RG fills the space between units 103R and 103G.

[0085] This allows the light-emitting device 550G(i,j) to be separated from the light-emitting device 550R(i,j). Furthermore, the gap formed between the light-emitting devices 550R(i,j) and 550G(i,j) can be filled using the filler material 529RG(i,j). Additionally, the step resulting from the gap between the light-emitting devices 550R(i,j) and 550G(i,j) can be reduced. Furthermore, the step resulting in the conductive film 552 can be reduced. Moreover, the phenomenon of cuts or tears forming in the conductive film 552 along the step can be suppressed. As a result, a novel display device with superior convenience, usefulness, and reliability can be provided.

[0086] <Example 2 of the composition of filler material 529RG(i,j)> For example, insulating inorganic materials, insulating organic materials, or insulating composite materials containing inorganic and organic materials can be used as fillers 529RG(i,j).

[0087] Specifically, an inorganic oxide film, an inorganic nitride film, or an inorganic oxidnitride film, or a laminated material made by laminating a combination of these, can be used as the filler 529RG(i,j).

[0088] For example, films containing silicon oxide films, silicon nitride films, silicon oxynitride films, aluminum oxide films, or laminated materials made by laminating multiple films selected from these can be used as filler material 529RG(i,j). Note that silicon nitride films are dense films and have excellent function in suppressing the diffusion of impurities.

[0089] For example, the filler 529RG(i,j) can be made of polyester, polyolefin, polyamide, polyimide, polycarbonate, polysiloxane, or acrylic resin, or a laminated or composite material of multiple resins selected from these.

[0090] <Example 3 of the composition of filler material 529RG(i,j)> The filler 529RG(i,j) comprises, for example, filler 529(1) and filler 529(2).

[0091] For example, insulating inorganic materials can be used as the filler 529(1). Specifically, aluminum oxide can be used as the filler 529(1). For example, a dense film formed using chemical vapor deposition or atomic layer deposition (ALD) can be used as the filler 529(1).

[0092] Furthermore, for example, an insulating organic material can be used as the filler 529(2). Specifically, polyimide or acrylic resin can be used as the filler 529(2). In addition, the filler 529(2) can be formed using a photosensitive material.

[0093] <Example of display device configuration 3> The display device 700 described in this embodiment includes a light-emitting device 550B(i,j) and a reflective film REFB(i,j) (see Figure 2). The display device 700 also includes filler material 529GB(i,j) and filler material 529BR(i,j). The light-emitting device 550B(i,j) is adjacent to the light-emitting device 550R(i,j+1).

[0094] <Example configuration of light-emitting device 550B(i,j) 1> The light-emitting device 550B(i,j) comprises electrodes 551B(i,j), 552B(i,j), and unit 103B(i,j).

[0095] Unit 103B(i,j) is sandwiched between electrodes 552B(i,j) and 551B(i,j), and electrode 551B(i,j) is sandwiched between unit 103B(i,j) and the insulating film 521.

[0096] 《Example configuration of electrode 551B(i,j)》 Electrode 551B(i,j) has a gap 551GB(i,j) between it and electrode 551G(i,j).

[0097] <Example 2 of the composition of conductive film 552> The conductive film 552 electrically connects electrodes 552G(i,j) and 552B(i,j).

[0098] The gap 551GB(i,j) is sandwiched between the conductive film 552 and the insulating film 521.

[0099] <Example 1 of the configuration of the reflective film REFB(i,j)> The reflective film REFB(i,j) is sandwiched between the electrode 551B(i,j) and the insulating film 521. Furthermore, the reflective film REFB(i,j) has a distance DB between it and the electrode 552B(i,j).

[0100] Distance DB is related to distance DR and distance DG in a way that satisfies all of the following equations (1) to (3). In other words, distance DB is longer than distance DR, distance DR is longer than distance DG, the difference between distance DB and distance DR is less than 60 nm, and the difference between distance DR and distance DG is less than 35 nm.

[0101]

number

[0102] <Example 2 of the configuration of the reflective film REFB(i,j)> The distance DB is less than 200 nm.

[0103] This makes it possible to reduce the step difference between the light-emitting device 550R(i,j) and the light-emitting device 550G(i,j). It also makes it possible to reduce the step difference between the light-emitting device 550G(i,j) and the light-emitting device 550B(i,j). Furthermore, it makes it possible to reduce the step difference between the light-emitting device 550R(i,j) and the light-emitting device 550B(i,j). In addition, it makes it possible to reduce the step difference in the conductive film 552. Furthermore, it makes it possible to suppress the phenomenon of cuts or tears occurring in the conductive film 552 along the step. As a result, it is possible to provide a novel optical functional device with superior convenience, usefulness, and reliability.

[0104] <Example of display device configuration 4> The display device 700 described in this embodiment includes a light-emitting device 550B(i,j) and a reflective film REFB(i,j) (see Figure 3).

[0105] <Example 3 of the configuration of the reflective film REFB(i,j)> The reflective film REFB(i,j) is sandwiched between the electrode 551B(i,j) and the insulating film 521. Furthermore, the reflective film REFB(i,j) has a distance DB between it and the electrode 552B(i,j).

[0106] Distance DB is related to distance DR and distance DG in a way that satisfies all of the following equations (1) to (3). In other words, distance DR is longer than distance DG, distance DG is longer than distance DB, the difference between distance DR and distance DG is less than 35 nm, and the difference between distance DG and distance DB is less than 35 nm.

[0107]

number

[0108] <Example 4 of the configuration of the reflective film REFR(i,j)> The distance DR is less than 150 nm.

[0109] This makes it possible to reduce the step difference between the light-emitting device 550R(i,j) and the light-emitting device 550G(i,j). It also makes it possible to reduce the step difference between the light-emitting device 550G(i,j) and the light-emitting device 550B(i,j). Furthermore, it makes it possible to reduce the step difference between the light-emitting device 550R(i,j) and the light-emitting device 550B(i,j). In addition, it makes it possible to reduce the step difference in the conductive film 552. Furthermore, it makes it possible to suppress the phenomenon of cuts or tears occurring in the conductive film 552 along the step. As a result, it is possible to provide a novel optical functional device with superior convenience, usefulness, and reliability.

[0110] 《Example configuration of Unit 103R(i,j)》 Unit 103R(i,j) is equipped with the function of emitting optical ELR, and the optical ELR has wavelengths between 600 nm and 740 nm (see Figure 3).

[0111] For example, the configuration described in Embodiment 2 can be used for unit 103R(i,j).

[0112] 《Example configuration of Unit 103B(i,j)》 Unit 103B(i,j) is equipped with the function of emitting optical ELB, and the optical ELB has wavelengths between 400 nm and 480 nm (see Figure 3).

[0113] For example, the configuration described in Embodiment 2 can be used for unit 103B(i,j).

[0114] This makes it possible to reduce the step difference between the light-emitting device 550R(i,j) and the light-emitting device 550B(i,j). It also makes it possible to reduce the step difference in the conductive film 552. Furthermore, it is possible to suppress the phenomenon of cuts or tears occurring in the conductive film 552 along the step difference. In addition, red light can be used for display. In addition, blue light can be used for display. As a result, a novel display device with superior convenience, usefulness, and reliability can be provided.

[0115] <Example configuration of light-emitting device 550R(i,j) 2> The light-emitting device 550R(i,j) comprises layer 104R(i,j), which is sandwiched between unit 103R(i,j) and electrode 551R(i,j).

[0116] Example of layer 104R(i,j) configuration Layer 104R(i,j) contains an electron-accepting material AM and a hole-transporting material HTM. Furthermore, layer 104R(i,j) contains 1 × 10⁻¹⁶ 2 [Ω cm] or more 1×10 8 It has an electrical resistivity of [Ω·cm] or less.

[0117] For example, the configuration of layer 104 described in Embodiment 3 can be used for layer 104R(i,j).

[0118] <Example configuration of light-emitting device 550G(i,j) 2> The light-emitting device 550G(i,j) comprises layer 104G(i,j), which is sandwiched between unit 103G(i,j) and electrode 551G(i,j). Furthermore, layer 104G(i,j) has a gap 104RG(i,j) between it and layer 104R(i,j). Note that the gap 104RG(i,j) can be formed, for example, by etching.

[0119] Specifically, in the first step, a film that will become layer 104R(i,j), a laminated film that will become unit 103R(i,j), and a first sacrificial layer that protects unit 103R(i,j) are formed on electrode 551R(i,j) in this order. In the second step, the first sacrificial layer, unit 103R(i,j), and layer 104R(i,j) are formed into predetermined shapes using photolithography and etching. When removing the unnecessary portion of the laminated film that will become unit 103R(i,j) using etching, the thinner the thickness of the laminated film, the less residue is generated and the easier the processing becomes.

[0120] Next, in the third step, a first sacrificial layer protecting unit 103R(i,j), a film that will become layer 104G(i,j) on electrode 551G(i,j), a laminated film that will become unit 103G(i,j), and a second sacrificial layer protecting unit 103G(i,j) are formed in this order. In the fourth step, the second sacrificial layer, unit 103G(i,j), and layer 104G(i,j) are formed into predetermined shapes using photolithography and etching. When removing unnecessary portions of the laminated film that will become unit 103G(i,j) using etching, the thinner the thickness of the laminated film, the less residue is generated and the easier the processing becomes.

[0121] In this fourth step, a gap 104RG(i,j) can be formed.

[0122] Example configuration of layer 104G(i,j) Layer 104G(i,j) contains an electron-accepting material AM and a hole-transporting material HTM.

[0123] For example, the configuration of layer 104 described in Embodiment 3 can be used for layer 104G(i,j).

[0124] This makes it possible to suppress the current flowing between layer 104R(i,j) and layer 104G(i,j). Furthermore, it is possible to suppress the crosstalk phenomenon occurring between light-emitting devices 550R(i,j) and 550G(i,j). As a result, a novel display device with superior convenience, usefulness, and reliability can be provided.

[0125] In this specification, devices fabricated using a metal mask or FMM (Fine Metal Mask, a high-resolution metal mask) may be referred to as MM (Metal Mask) structured devices. Furthermore, in this specification, devices fabricated without using a metal mask or FMM may be referred to as MML (Metal Maskless) structured devices. Because MML structured display devices are fabricated without a metal mask, they offer greater design flexibility in terms of pixel arrangement and pixel shape compared to FMM or MM structured display devices.

[0126] Furthermore, in the manufacturing method for MML-structured display devices, island-shaped EL layers are not formed by the pattern of the metal mask, but rather by processing after the EL layer has been deposited on the entire surface. Therefore, it is possible to realize high-definition display devices or display devices with a high aperture ratio, which were previously difficult to achieve. In addition, since the EL layer can be manufactured separately for each color, it is possible to realize a display device that is extremely vivid, has high contrast, and has high display quality. Moreover, by providing a sacrificial layer on the EL layer, the damage that the EL layer receives during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

[0127] Furthermore, a display device according to one aspect of the present invention may have a structure in which no insulator is provided to cover the ends of the pixel electrodes. In other words, there is no insulator provided between the pixel electrodes and the EL layer. This configuration allows for efficient extraction of light emitted from the EL layer, thereby significantly reducing the viewing angle dependence. For example, in a display device according to one aspect of the present invention, the viewing angle (the maximum angle at which a constant contrast ratio is maintained when viewing the screen from an oblique direction) can be set to a range of 100° or more and less than 180°, preferably 150° or more and 170° or less. The above viewing angle can be applied to both the vertical and horizontal directions. By using a display device according to one aspect of the present invention, the viewing angle dependence is improved, and the visibility of the image can be enhanced.

[0128] Furthermore, when using a fine metal mask (FMM) structure for the display device, there may be limitations on the pixel arrangement configuration. The FMM structure will be explained below.

[0129] To fabricate an FMM structure, a metal mask (also called an FMM) with openings is set opposite the substrate so that the EL material is deposited in the desired area during EL deposition. Then, EL deposition is performed through the FMM to deposit the EL material in the desired area. As the size of the substrate increases during EL deposition, the size and weight of the FMM also increase. In addition, the FMM may deform because heat is applied to it during EL deposition. Alternatively, there are methods that apply a certain tension to the FMM during EL deposition, so the weight and strength of the FMM are important parameters.

[0130] Therefore, when designing the pixel arrangement configuration of an FMM structure device, it is necessary to consider the above parameters and other factors, and the design must be considered under certain limitations. On the other hand, in one embodiment of the present invention, since the display device is manufactured using an MML structure, it offers superior effects such as greater flexibility in the pixel arrangement configuration compared to the FMM structure. Furthermore, this configuration has high compatibility with flexible devices, for example, and various circuit arrangements can be used for either the pixels or the driving circuit, or both.

[0131] Furthermore, one embodiment of the present invention is a display device having an OS transistor and a light-emitting device with an MML (metal maskless) structure. This configuration makes it possible to extremely reduce the leakage current that can flow through the transistor and the leakage current that can flow between adjacent light-emitting elements (also called lateral leakage current or side leakage current). With this configuration, when an image is displayed on the display device, the observer can observe one or more of the following: image sharpness, image clarity, high saturation, and high contrast ratio. Moreover, by having an extremely low leakage current that can flow through the transistor and lateral leakage current between light-emitting elements, it is possible to achieve a display (also called true black display) with as little light leakage (so-called white floating) that may occur when displaying black as possible.

[0132] This embodiment can be appropriately combined with other embodiments shown in this specification.

[0133] (Embodiment 2) In this embodiment, the configuration of a light-emitting device that can be used in a display device according to one aspect of the present invention will be described with reference to Figure 4.

[0134] Figure 4A is a cross-sectional view illustrating the configuration of a light-emitting device 550 according to one embodiment of the present invention, and Figure 4B is a diagram illustrating the energy levels of the material used in the light-emitting device 550 according to one embodiment of the present invention.

[0135] The configuration of the light-emitting device 550 described in this embodiment can be applied to light-emitting devices 550R(i,j), 550G(i,j), or 550B(i,j). Specifically, the code "550" used in the description of the light-emitting device 550 can be read as "550R(i,j)", "550G(i,j)", or "550B(i,j)" and used in the description of the light-emitting device 550R(i,j), 550G(i,j), or 550B(i,j). Similarly, the codes attached to the elements constituting the light-emitting device 550 can also be read as appropriate.

[0136] For example, the code "103" used in the description of unit 103 can be replaced with "103R(i,j)", "103G(i,j)", or "103B(i,j)" and used in the descriptions of unit 103R(i,j), unit 103G(i,j), or unit 103B(i,j).

[0137] <Example configuration of light-emitting device 550> The light-emitting device 550 described in this embodiment includes an electrode 551, an electrode 552X, and a unit 103. Electrode 552X has a region that overlaps with electrode 551, and unit 103 has a region sandwiched between electrode 551 and electrode 552X.

[0138] <Example configuration of Unit 103> Unit 103 has a single-layer structure or a multi-layer structure. For example, unit 103 has layers 111, 112, and 113 (see Figure 4A). Unit 103 has the function of emitting optical EL1.

[0139] Layer 111 includes a region sandwiched between layers 112 and 113, layer 112 includes a region sandwiched between electrode 551 and layer 111, and layer 113 includes a region sandwiched between electrode 552X and layer 111.

[0140] For example, a layer selected from functional layers such as an emissive layer, a hole transport layer, an electron transport layer, and a carrier block layer can be used in unit 103. Furthermore, a layer selected from functional layers such as a hole injection layer, an electron injection layer, an exciton block layer, and a charge generation layer can also be used in unit 103.

[0141] Example of Layer 112 configuration For example, a hole-transporting material can be used for layer 112. Layer 112 can also be referred to as a hole-transporting layer. It is preferable to use a material for layer 112 that has a larger band gap than the luminescent material contained in layer 111. This suppresses energy transfer from excitons generated in layer 111 to layer 112.

[0142] [Materials with hole transport properties] The hole mobility is 1 × 10⁻⁶. -6 cm 2 Materials with a Vs of 1 / V or higher can be suitably used as materials with hole transport properties.

[0143] For example, amine compounds or organic compounds having a π-electron-rich heteroaromatic ring skeleton can be used in hole-transporting materials. Specifically, compounds having an aromatic amine skeleton, a carbazole skeleton, a thiophene skeleton, a furan skeleton, etc., can be used. Compounds having an aromatic amine skeleton or a carbazole skeleton are particularly preferred because they offer good reliability, high hole transportability, and contribute to reducing the driving voltage.

[0144] Examples of compounds having an aromatic amine skeleton include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviated as TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as mBPAFLP), and 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBA1BP). ,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), etc. can be used.

[0145] Examples of compounds having a carbazole skeleton include 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), and the like.

[0146] Examples of compounds having a thiophene skeleton include, for example, 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), etc., which can be used.

[0147] Examples of compounds having a furan skeleton include, for example, 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), etc., which can be used.

[0148] <<Example of the structure of layer 113>> For example, a material having electron transporting properties, a material having an anthracene skeleton, a mixed material, etc. can be used for layer 113. Also, layer 113 can be referred to as an electron transport layer. In addition, a configuration in which a material having a larger band gap than the luminescent material contained in layer 111 is used for layer 113 is preferable. Thereby, energy transfer from excitons generated in layer 111 to layer 113 can be suppressed.

[0149] [Material having electron transporting properties] For example, a metal complex or an organic compound having a π-electron deficient heteroaromatic ring skeleton can be used as the material having electron transporting properties.

[0150] Under the condition that the square root of the electric field strength [V / cm] is 600, the electron mobility is 1×10 -7 cm 2 / Vs or more and 5×10 -5 cm 2Materials with a Vs of 0.5 or less can be suitably used as electron-transporting materials. This makes it possible to suppress electron transport in the electron transport layer, control the amount of electrons injected into the light-emitting layer, or prevent the light-emitting layer from becoming electron-excessive.

[0151] Examples of metal complexes that can be used include bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviated as BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviated as BAlq), bis(8-quinolinolato)zinc(II) (abbreviated as Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviated as ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviated as ZnBTZ), and the like.

[0152] Organic compounds having a π-electron-deficient heteroaromatic ring skeleton include, for example, 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 a pyridine skeleton are preferred due to their good reliability. Furthermore, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton have high electron transport properties, which can reduce the driving voltage.

[0153] Examples of heterocyclic compounds having a polyazole skeleton include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated as PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated as TAZ), and 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviated as O XD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl]-9H-carbazole (abbreviated as CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviated as TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviated as mDBTBIm-II), etc. can be used.

[0154] 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), and 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h Quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis[3-(phenanthren-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.

[0155] Examples of heterocyclic compounds having a pyridine skeleton include 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), and others.

[0156] 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) and 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), etc. can be used.

[0157] [Materials containing an anthracene skeleton] Organic compounds having an anthracene skeleton can be used in layer 113. In particular, organic compounds containing both an anthracene skeleton and a heterocyclic skeleton can be preferably used.

[0158] 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 a nitrogen-containing five-membered ring skeleton with two heteroatoms in the ring and an anthracene skeleton can be used. Specifically, pyrazole rings, imidazole rings, oxazole rings, thiazole rings, etc., can be suitably used as the heterocyclic skeleton.

[0159] 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 a nitrogen-containing six-membered ring skeleton with two heteroatoms in the ring and an anthracene skeleton can be used. Specifically, pyrazine rings, pyrimidine rings, pyridazine rings, etc., can be suitably used as the heterocyclic skeleton.

[0160] [Example of mixed material composition] Furthermore, a material composed of a mixture of multiple substances can be used in layer 113. Specifically, a mixed material containing an alkali metal, alkali metal compound, or alkali metal complex and an electron-transporting substance can be used in layer 113. It is more preferable that the HOMO level of the electron-transporting material is -6.0 eV or higher.

[0161] For example, a composite material of an electron-accepting material and a hole-transporting material can be used in layer 104. Specifically, a composite material of an electron-accepting material and a material having a relatively deep HOMO level HM1 between -5.7 eV and -5.4 eV can be used in layer 104 (see Figure 4B). By combining this composite material in layer 104 with other materials, the mixed material can be suitably used in layer 113. This improves the reliability of the light-emitting device.

[0162] Furthermore, the configuration in which the mixed material is used as layer 113 and the composite material as layer 104 can be suitably combined with a configuration in which a hole-transporting material is used as layer 112. For example, a material having a HOMO level HM2 in the range of -0.2eV to 0eV relative to the relatively deep HOMO level HM1 can be used as layer 112 (see Figure 4B). This can improve the reliability of the light-emitting device. In this specification, the above light-emitting device may be referred to as a Recombination-Site Tailoring Injection structure (ReSTI structure).

[0163] A configuration in which alkali metals, alkali metal compounds, or alkali metal complexes are present in the thickness direction of layer 113 with a concentration difference (including cases where the concentration is zero) is preferred.

[0164] For example, metal complexes containing an 8-hydroxyquinolinate structure can be used. Alternatively, methyl-substituted metal complexes containing an 8-hydroxyquinolinate structure (e.g., 2-methyl-substituted or 5-methyl-substituted) can also be used.

[0165] As metal complexes containing the 8-hydroxyquinolinate structure, 8-hydroxyquinolinate-lithium (abbreviated as Liq), 8-hydroxyquinolinate-sodium (abbreviated as Naq), etc., can be used. In particular, monovalent metal ion complexes are preferred, among lithium complexes, and Liq is more preferred.

[0166] 《Example of Layer 111 Configuration 1》 For example, a luminescent material, or a luminescent material and a host material, can be used for layer 111. Layer 111 can also be referred to as a light-emitting layer. It is preferable to position layer 111 in a region where holes and electrons recombine. This allows the energy generated by carrier recombination to be efficiently emitted as light.

[0167] Furthermore, it is preferable to position the layer 111 away from the metal used for electrodes, etc. This makes it possible to suppress the quenching phenomenon caused by the metal used for electrodes, etc.

[0168] Furthermore, it is preferable to adjust the distance from the reflective electrodes, etc., to the layer 111 and position the layer 111 at an appropriate location according to the emission wavelength. This allows for the amplification of the light amplitudes by utilizing the interference phenomenon between the light reflected by the electrodes, etc., and the light emitted by the layer 111. It also allows for the amplification of light of a predetermined wavelength, thereby narrowing the light spectrum. Moreover, a vivid emission color can be obtained with high intensity. In other words, by positioning the layer 111 at an appropriate location between the electrodes, etc., a microcavity structure can be constructed.

[0169] For example, fluorescent materials, phosphorescent materials, or materials exhibiting thermally delayed fluorescence (TADF) (also known as TADF materials) can be used as luminescent materials. This allows the energy generated by carrier recombination to be released from the luminescent material as photo-EL1 (see Figure 4A).

[0170] [Fluorescent material] A fluorescent material can be used in layer 111. For example, the fluorescent materials exemplified below can be used in layer 111. However, this is not limited to these examples, and various known fluorescent materials can be used in layer 111.

[0171] Specifically, these include 5,6-bis[4-(10-phenyl-9-antryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-antryl)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), and N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl] Nyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation :2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazole-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-carbazole-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-carbazole-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.

[0172] In particular, condensed aromatic diamine compounds, such as pyrenediamine compounds like 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03, are preferred because they exhibit high hole-trapping properties and excellent luminescence efficiency or reliability.

[0173] 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]chrysen-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl You can use ru-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-carbazole-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracene-9-amine (abbreviation: DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubren, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), etc.

[0174] Also, 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]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis (4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluorantene-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]k [Noridin-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]quinoridin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(di You can use methylamino)phenyl]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]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), etc.

[0175] [Phosphorescent material] A phosphorescent material can be used in layer 111. For example, the phosphorescent materials exemplified below can be used in layer 111. However, it is not limited to these, and various known phosphorescent materials can be used in layer 111.

[0176] 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 with 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, etc., can be used in layer 111.

[0177] [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-triazole-3-yl-κN2]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.

[0178] 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.

[0179] 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]phenanthridine]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), etc.

[0180] Examples of organometallic iridium complexes using phenylpyridine derivatives having electron-withdrawing groups as ligands include bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’ Iridium(III) tetrakis(1-pyrazolyl) borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’ Iridium(III) picolinate (abbreviation: Firpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinate-N,C 2’ Iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’ Iridium(III) acetylacetonate (abbreviated as FIracac), etc., can be used.

[0181] These compounds exhibit blue phosphorescence and have emission wavelength peaks between 440 nm and 520 nm.

[0182] [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.

[0183] Examples of organometallic iridium complexes having a pyrazine skeleton include (acetylacetonato)bis(3,5-dimethyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]), etc.

[0184] Examples of organometallic iridium complexes having a pyridine skeleton include tris(2-phenylpyridinato-N,C) 2’ Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinate-N,C) 2’Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinate)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinate)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinate-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-(2-pyridinyl-κN)benzofl[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κ]iridium(III) (abbreviation: [Ir(5mppy-d3)2(mbfpypy-d3)]), [2-d3-methyl-(2-pyridinyl-κN)benzofl[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy-d3)]), etc. can be used.

[0185] Examples of rare earth metal complexes include tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]).

[0186] These compounds primarily exhibit green phosphorescence and have emission wavelength peaks between 500 nm and 600 nm. Furthermore, organometallic iridium complexes with a pyrimidine skeleton are remarkably superior in terms of reliability or luminescence efficiency.

[0187] [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](dipvaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), bis[4,6-di(naphthalene-1-yl)pyrimidinato](dipvaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), etc.

[0188] Examples of organometallic iridium complexes having a pyrazine skeleton include (acetylacetonato)bis(2,3,5-triphenylpyradinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyradinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), etc.

[0189] 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.

[0190] Examples of rare earth metal complexes that can be used include tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]), tris[1-(2-tenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]), etc.

[0191] Examples of platinum complexes that can be used include 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviated as PtOEP).

[0192] These compounds exhibit red phosphorescence and have an emission peak between 600 nm and 700 nm. Furthermore, organometallic iridium complexes with a pyrazine skeleton produce red emission with a chromaticity suitable for use in display devices.

[0193] [Substances exhibiting thermally activated delayed fluorescence (TADF)] TADF material can be used for layer 111. For example, the TADF material exemplified below can be used as the luminescent material. However, it is not limited to this, and various known TADF materials can be used as the luminescent material.

[0194] TADF materials have a small difference between the S1 and T1 energy levels, allowing for reverse intersystem crossing (upconversion) from a triplet excited state to a singlet excited state with minimal thermal energy. This enables efficient generation of singlet excited states from triplet excited states. Furthermore, the triplet excitation energy can be converted into luminescence.

[0195] Furthermore, an excited complex (also called an exciplex) that forms an excited state with two types of substances has an extremely small difference between the S1 and T1 levels and functions as a TADF material that can convert triplet excitation energy into singlet excitation energy.

[0196] Note that as the index of the T1 level, a phosphorescence spectrum observed at a low temperature (for example, from 77K to 10K) may be used. As the TADF material, a tangent is drawn at the trailing edge on the short wavelength side of its fluorescence spectrum, and the energy of the wavelength of the extrapolated line is taken as the S1 level. When a tangent is drawn at the trailing edge on the short wavelength side of the phosphorescence spectrum and the energy of the wavelength of the extrapolated line is taken as the T1 level, it is preferable that the difference between S1 and T1 is 0.3 eV or less, and more preferably 0.2 eV or less.

[0197] Also, when using a TADF material as the luminescent substance, it is preferable that the S1 level of the host material is higher than the S1 level of the TADF material. Also, it is preferable that the T1 level of the host material is higher than the T1 level of the TADF material.

[0198] For example, fullerenes and their derivatives, acridines and their derivatives, eosin derivatives, etc. can be used as the TADF material. Also, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd), etc. can be used as the TADF material.

[0199] Specifically, protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(Etio I)), octaethylporphyrin-platinum chloride complex (PtCl2OEP), etc. whose structural formulas are shown below can be used.

[0200]

Chemical formula

[0201] In addition, for example, a heterocyclic compound having one or both of a π-electron-rich heterocyclic aromatic ring and a π-electron-deficient heterocyclic aromatic ring can be used as the TADF material.

[0202] Specifically, 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[acridine-9,9'-anthracene]-10'-one (abbreviation: ACRSA), etc., whose structural formulas are shown below, can be used.

[0203]

Chemical formula

[0204] The heterocyclic compound is preferred because it has both a π-electron-excess heteroaromatic ring and a π-electron-deficient heteroaromatic ring, resulting in high electron transport and hole transport properties. In particular, among the skeletons having a π-electron-deficient heteroaromatic ring, the pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and triazine skeleton are preferred because they are stable and reliable. In particular, the benzoflopyrimidine skeleton, benzothienopyrimidine skeleton, benzoflopyrazine skeleton, and benzothienopyrazine skeleton are preferred because they have high electron-withdrawing properties and are reliable.

[0205] Furthermore, among skeletons having a π-electron-excess heteroaromatic ring, the acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton are stable and reliable, and therefore it is preferable to have at least one of these skeletons. Dibenzofuran is preferred as the furan skeleton, and dibenzothiophene is preferred as the thiophene skeleton. Indole, carbazole, indrocarbazole, bicarbazole, and 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole are particularly preferred as the pyrrole skeleton.

[0206] Furthermore, materials in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded are particularly preferred because both the electron-donating ability of the π-electron-rich heteroaromatic ring and the electron-accepting ability of the π-electron-deficient heteroaromatic ring are strengthened, and the energy difference between the S1 and T1 levels is reduced, thus efficiently obtaining thermally activated delayed fluorescence. Alternatively, 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. Additionally, aromatic amine skeletons, phenazine skeletons, and the like can be used as the π-electron-rich skeleton.

[0207] Furthermore, as π-electron-deficient skeletons, xanthene skeletons, thioxanthene dioxide skeletons, oxadiazole skeletons, triazole skeletons, imidazole skeletons, anthraquinone skeletons, boron-containing skeletons such as phenylborane or volanthrene, aromatic rings or heteroaromatic rings having a nitrile group or cyano group such as benzonitrile or cyanobenzene, carbonyl skeletons such as benzophenone, phosphine oxide skeletons, sulfone skeletons, and the like can be used.

[0208] Thus, a π-electron-deficient skeleton and a π-electron-excess skeleton can be used instead of at least one of a π-electron-deficient heteroaromatic ring and a π-electron-excess heteroaromatic ring.

[0209] 《Example of Layer 111 Configuration 2》 Materials with carrier transport properties can be used as the host material. For example, materials with hole transport properties, materials with electron transport properties, materials exhibiting thermally delayed fluorescence (TADF), materials with an anthracene skeleton, and mixed materials can be used as the host material. It is preferable to use a material with a larger band gap than the luminescent material contained in layer 111 as the host material. This makes it possible to suppress energy transfer from excitons generated in layer 111 to the host material.

[0210] [Materials with hole transport properties] The hole mobility is 1 × 10⁻⁶. -6 cm 2 Materials with a Vs of 1 / V or higher can be suitably used as materials with hole transport properties.

[0211] For example, a hole-transporting material that can be used in layer 112 can be used in layer 111. Specifically, a hole-transporting material that can be used in a hole-transporting layer can be used in layer 111.

[0212] [Materials with electron transport properties] For example, an electron-transporting material that can be used in layer 113 can be used in layer 111. Specifically, an electron-transporting material that can be used in an electron transport layer can be used in layer 111.

[0213] [Materials containing an anthracene skeleton] Organic compounds having an anthracene skeleton can be used as host materials. In particular, organic compounds having an anthracene skeleton are suitable when fluorescent materials are used as the light-emitting material. This makes it possible to realize light-emitting devices with good luminescence efficiency and durability.

[0214] Among organic compounds having an anthracene skeleton, organic compounds having a diphenylanthracene skeleton, particularly a 9,10-diphenylanthracene skeleton, are preferred because they are chemically stable. Furthermore, when the host material has a carbazole skeleton, it is preferred because the hole injection and transport properties are enhanced. In particular, when the host material contains a dibenzocarbazole skeleton, the HOMO level becomes about 0.1 eV shallower than that of carbazole, making it easier for holes to enter, and it is also preferred because it 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 a carbazole skeleton.

[0215] Therefore, substances having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton, substances having both a 9,10-diphenylanthracene skeleton and a benzocarbazole skeleton, and substances having both a 9,10-diphenylanthracene skeleton and a dibenzocarbazole skeleton are preferred as host materials.

[0216] 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 [Lu-9-anthryl)phenyl]-9H-carbazole (abbreviated as PCzPA), 9-[4-(10-phenyl-9-antracenyl)phenyl]-9H-carbazole (abbreviated as CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviated as cgDBCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), etc. can be used.

[0217] In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA exhibit very good characteristics.

[0218] [Substances exhibiting thermally activated delayed fluorescence (TADF)] TADF materials can be used as host materials. When TADF materials are used as host materials, the triplet excitation energy generated by the TADF material can be converted into singlet excitation energy through reverse intersystem crossing. Furthermore, the excitation energy can be transferred to the 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 increase the luminescence efficiency of the light-emitting device.

[0219] This is particularly effective when the light-emitting material is a fluorescent material. Furthermore, in order to obtain high luminescence efficiency, it is preferable that the S1 level of the TADF material is higher than that of the fluorescent material. Also, it is preferable that the T1 level of the TADF material is higher than that of the fluorescent material. Therefore, it is preferable that the T1 level of the TADF material is higher than that of the fluorescent material.

[0220] Moreover, it is preferable to use a TADF material that exhibits emission overlapping with the wavelength of the absorption band on the lowest energy side of the fluorescent emitting substance. By doing so, the transfer of excitation energy from the TADF material to the fluorescent emitting substance becomes smooth, and light emission can be efficiently obtained, which is preferable.

[0221] In addition, in order for singlet excitation energy to be efficiently generated from triplet excitation energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. Also, it is preferable that the triplet excitation energy generated in the TADF material does not move to the triplet excitation energy of the fluorescent emitting substance. For this purpose, it is preferable that the fluorescent emitting substance has a protecting group around the luminophore (the skeleton causing light emission) of the fluorescent emitting substance. As the protecting group, a substituent having no π bond is preferable, a saturated hydrocarbon is preferable, and specifically, an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a trialkylsilyl group having 3 to 10 carbon atoms can be mentioned. It is more preferable that there are a plurality of protecting groups. Since a substituent having no π bond has poor ability to transport carriers, it can increase the distance between the TADF material and the luminophore of the fluorescent emitting substance with little influence on carrier transport or carrier recombination.

[0222] Here, the luminophore refers to an atomic group (skeleton) that causes light emission in the fluorescent emitting substance. The luminophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring.

[0223] Examples of the condensed aromatic ring or the condensed heteroaromatic ring include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, etc. In particular, fluorescent emitting 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, and a naphthobisbenzofuran skeleton are preferable because they have a high fluorescence quantum yield.

[0224] For example, TADF material, which can be used as a luminescent material, can be used as a host material.

[0225] [Example of mixed material composition 1] Furthermore, a material composed of a mixture of multiple substances can be used as the host material. For example, a material with electron-transporting properties and a material with hole-transporting properties can be used in the mixture. The weight ratio of the material with hole-transporting properties to the material with electron-transporting properties in the mixture should be (material with hole-transporting properties / material with electron-transporting properties) = (1 / 19) or more and (19 / 1) or less. This allows for easy adjustment of the carrier transport properties of layer 111. In addition, the recombination region can be easily controlled.

[0226] [Example of mixed material composition 2] A material mixed with a phosphorescent substance can be used as a host material. The phosphorescent substance can also be used as an energy donor to supply excitation energy to a fluorescent substance when a fluorescent substance is used as the light-emitting material.

[0227] [Example of mixed material composition 3] A mixed material containing a material that forms an excited complex can be used as the host material. For example, a material in which the emission spectrum of the formed excited complex overlaps with the wavelength of the lowest energy absorption band of the luminescent material can be used as the host material. This allows for smoother energy transfer and improves luminescence efficiency. Alternatively, the driving voltage can be suppressed. With such a configuration, luminescence using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the excited complex to the luminescent material (phosphorescent material), can be efficiently obtained.

[0228] A phosphorescent material can be used as at least one of the materials forming the excitation complex. This allows for the utilization of reverse intersystem crossing. Alternatively, the triplet excitation energy can be efficiently converted to the singlet excitation energy.

[0229] For a combination of materials to form an excited complex, it is preferable that the HOMO level of the hole-transporting material is higher than or equal to the HOMO level of the electron-transporting material. Alternatively, it is preferable that the LUMO level of the hole-transporting material is higher than or equal to the LUMO level of the electron-transporting material. This allows for efficient formation of the excited complex. The LUMO and HOMO levels of the materials can be derived from their electrochemical properties (reduction potential and oxidation potential). Specifically, the reduction potential and oxidation potential can be measured using cyclic voltammetry (CV) measurement.

[0230] The formation of excited complexes can be confirmed, for example, by comparing the emission spectra of a hole-transporting material, an electron-transporting material, and a mixed film made by mixing these materials, and observing that the emission spectrum of the mixed film shifts to a longer wavelength than the emission spectra of each individual material (or has a new peak on the longer wavelength side). Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of a hole-transporting material, the transient PL of an electron-transporting material, and the transient PL of a mixed film made by mixing these materials, and observing differences in the transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component or a larger proportion of the delayed component than the transient PL lifetime of each individual material. Furthermore, the transient PL mentioned above can be replaced with transient electroluminescence (EL). That is, the formation of excited complexes can also be confirmed by comparing the transient EL of a hole-transporting material, the transient EL of an electron-transporting material, and the transient EL of a mixed film made by mixing these materials, and observing the differences in the transient response.

[0231] This embodiment can be appropriately combined with other embodiments shown in this specification.

[0232] (Embodiment 3) In this embodiment, the configuration of a light-emitting device that can be used in a display device according to one aspect of the present invention will be described with reference to Figure 4.

[0233] The configuration of the light-emitting device 550 described in this embodiment can be applied to light-emitting devices 550R(i,j), 550G(i,j), or 550B(i,j). Specifically, the code "550" used in the description of the light-emitting device 550 can be read as "550R(i,j)", "550G(i,j)", or "550B(i,j)" and used in the description of the light-emitting device 550R(i,j), 550G(i,j), or 550B(i,j). Similarly, the codes attached to the elements constituting the light-emitting device 550 can also be read as appropriate.

[0234] For example, the code "551" used in the description of electrode 551 can be replaced with "551R(i,j)", "551G(i,j)", or "551B(i,j)" and used to describe electrode 551R(i,j), electrode 551G(i,j), or electrode 551B(i,j).

[0235] Furthermore, the code "104" used in the description of layer 104 can be replaced with "104R(i,j)", "104G(i,j)", or "104B(i,j)" and used to describe layers 104R(i,j), 104G(i,j), or 104B(i,j).

[0236] <Example configuration of light-emitting device 550> The light-emitting device 550 described in this embodiment includes an electrode 551, an electrode 552X, a unit 103, and a layer 104. Electrode 552X has a region that overlaps with electrode 551, and unit 103 has a region sandwiched between electrode 551 and electrode 552X. Layer 104 also has a region sandwiched between electrode 551 and unit 103. For example, the configuration described in Embodiment 2 can be used for unit 103.

[0237] <Example configuration of electrode 551> For example, conductive materials can be used for the electrode 551. Specifically, a film containing a metal, alloy, or conductive compound can be used for the electrode 551 in a single layer or in a multilayer structure.

[0238] For example, a film that efficiently reflects light can be used for the electrode 551. Specifically, an alloy containing silver and copper, an alloy containing silver and palladium, or a metal film such as aluminum can be used for the electrode 551.

[0239] Furthermore, for example, a metal film that transmits some of the light and reflects other parts of the light can be used for the electrode 551. This allows a microcavity structure to be provided in the light-emitting device 550. Alternatively, light of a predetermined wavelength can be extracted more efficiently than other light. Alternatively, light with a narrow full width at half maximum can be extracted. Alternatively, light of vivid colors can be extracted.

[0240] Furthermore, for example, a film that is transparent to visible light can be used for the electrode 551. Specifically, a thin metal film, alloy film, or conductive oxide film that is thin enough to transmit light can be used for the electrode 551 in a single layer or in a multilayer structure.

[0241] In particular, materials with a work function of 4.0 eV or higher can be suitably used for the electrode 551.

[0242] For example, conductive oxides containing indium can be used. Specifically, indium oxide, indium oxide-tin oxide (abbreviated as ITO), indium oxide-tin oxide containing silicon or silicon oxide (abbreviated as ITSO), indium oxide-zinc oxide, indium oxide containing tungsten oxide and zinc oxide (abbreviated as IWZO), etc., can be used.

[0243] Furthermore, conductive oxides containing zinc can be used, for example. Specifically, zinc oxide, zinc oxide with added gallium, and zinc oxide with added aluminum can be used.

[0244] In addition, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or nitrides of metallic materials (e.g., titanium nitride) can be used. Alternatively, graphene can be used.

[0245] Example of Layer 104 configuration For example, a material with hole-injection properties can be used for layer 104. Layer 104 can also be referred to as a hole-injection layer.

[0246] Specifically, an electron-accepting material can be used in layer 104. Alternatively, a composite material containing multiple types of materials can be used in layer 104. This makes it easier to inject holes, for example, from electrode 551. Alternatively, it can reduce the driving voltage of the light-emitting device.

[0247] [Substances with electron-accepting properties] Organic and inorganic compounds can be used as electron-accepting materials. Electron-accepting materials can extract electrons from adjacent hole transport layers or hole-transporting materials by applying an electric field.

[0248] For example, compounds having electron-withdrawing groups (halogen groups or cyano groups) can be used in electron-accepting materials. Furthermore, electron-accepting organic compounds are easily vapor-deposited and readily formed into films. This can increase the productivity of light-emitting devices.

[0249] Specifically, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviated as HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviated as F6-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malononitrile, etc. can be used.

[0250] In particular, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms, such as HAT-CN, are thermally stable and therefore preferred.

[0251] Furthermore, radialene derivatives having electron-withdrawing groups (especially halogen groups such as fluoro groups or cyano groups) are preferred because they have very high electron-accepting properties.[3]

[0252] Specifically, α,α',α''-1,2,3-cyclopropanetriylidenates[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenates[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenates[2,3,4,5,6-pentafluorobenzeneacetonitrile], etc., can be used.

[0253] Furthermore, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, and the like can be used as electron-accepting materials.

[0254] Furthermore, phthalocyanine-based complex compounds such as phthalocyanine (abbreviated as H2Pc) and copper phthalocyanine (CuPc), and compounds having an aromatic amine skeleton such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB) and N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviated as DNTPD) can be used.

[0255] Furthermore, polymers such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS) can be used.

[0256] [Example of composite material composition 1] Furthermore, for example, a composite material containing an electron-accepting substance and a hole-transporting material can be used for layer 104. This allows not only materials with a large work function but also materials with a small work function to be used for electrode 551. Alternatively, the material to be used for electrode 551 can be selected from a wide range of materials, regardless of the work function.

[0257] For example, compounds having an aromatic amine skeleton, carbazole derivatives, aromatic hydrocarbons, aromatic hydrocarbons having a vinyl group, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used as hole transport materials in composite materials. Furthermore, if the hole mobility is 1 × 10⁻⁶ -6 cm 2 Materials with a Vs of 1 / V or higher can be suitably used as materials with hole transport properties in composite materials.

[0258] Furthermore, materials with relatively deep HOMO levels can be suitably used as hole-transporting materials in composite materials. Specifically, it is preferable that the HOMO level is between -5.7 eV and -5.4 eV. This facilitates the injection of holes into unit 103. It also facilitates the injection of holes into layer 112. In addition, it can improve the reliability of the light-emitting device.

[0259] Examples of compounds having an aromatic amine skeleton include N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviated as DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviated as DNTPD), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviated as DPA3B).

[0260] Examples of carbazole derivatives include 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarb You can use zole (abbreviated as PCzPCN1), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviated as TCPB), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviated as CzPA), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, etc.

[0261] 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), and 2-tert-butyl-9,10 -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, etc. can be used.

[0262] Examples of aromatic hydrocarbons having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviated as DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviated as DPVPA), and the like.

[0263] Examples of polymer compounds that can be used include poly(N-vinylcarbazole) (abbreviated as PVK), poly(4-vinyltriphenylamine) (abbreviated as PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviated as PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviated as Poly-TPD), and the like.

[0264] Furthermore, for example, substances comprising any of the carbazole skeleton, dibenzofuran skeleton, dibenzothiophene skeleton, and anthracene skeleton can be suitably used as hole-transporting materials in composite materials. In addition, substances comprising aromatic amines having substituents including a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines having a naphthalene ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group can be used as hole-transporting materials in composite materials. Moreover, using a substance having an N,N-bis(4-biphenyl)amino group can improve the reliability of light-emitting devices.

[0265] 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), and 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: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazole-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazole-9-yl)phenyl]tris( 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-9Hcarbazole-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobio[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-Fluorene-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 [Fluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl N-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), N,N-bis(9,9- Dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-1-amine, etc. can be used.

[0266] [Example of composite material composition 2] For example, a composite material containing an electron-accepting substance, a hole-transporting material, and an alkali metal fluoride or alkaline earth metal fluoride can be used as a hole-injecting material. In particular, a composite material in which fluorine atoms make up 20% or more of the atomic ratio can be suitably used. This can lower the refractive index of layer 104. 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.

[0267] This embodiment can be appropriately combined with other embodiments shown in this specification.

[0268] (Embodiment 4) In this embodiment, the configuration of a light-emitting device that can be used in a display device according to one aspect of the present invention will be described with reference to Figure 4.

[0269] The configuration of the light-emitting device 550 described in this embodiment can be applied to light-emitting devices 550R(i,j), 550G(i,j), or 550B(i,j). Specifically, the code "550" used in the description of the light-emitting device 550 can be read as "550R(i,j)", "550G(i,j)", or "550B(i,j)" and used in the description of the light-emitting device 550R(i,j), 550G(i,j), or 550B(i,j). Similarly, the codes attached to the elements constituting the light-emitting device 550 can also be read as appropriate.

[0270] For example, the symbol "552X" used in the description of electrode 552X can be replaced with "552R(i,j)", "552G(i,j)", or "552B(i,j)" and used in the description of electrode 552R(i,j), electrode 552G(i,j), or electrode 552B(i,j).

[0271] <Example configuration of light-emitting device 550> The light-emitting device 550 described in this embodiment includes an electrode 551, an electrode 552X, a unit 103, and a layer 105. Electrode 552X has a region that overlaps with electrode 551, and unit 103 has a region sandwiched between electrode 551 and electrode 552X. Layer 105 also has a region sandwiched between unit 103 and electrode 552X. For example, the configuration described in Embodiment 2 can be used for unit 103.

[0272] <Example configuration of electrode 552X> For example, conductive materials can be used for electrode 552X. Specifically, materials containing metals, alloys, or conductive compounds can be used for electrode 552X in a single layer or in a multilayer structure.

[0273] For example, the material that can be used for electrode 551 described in Embodiment 3 can be used for electrode 552X. In particular, a material with a smaller work function than electrode 551 can be suitably used for electrode 552X. Specifically, a material with a work function of 3.8 eV or less is preferred.

[0274] 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 electrode 552X.

[0275] Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), strontium (Sr), europium (Eu), ytterbium (Yb), and alloys containing these elements (MgAg, AlLi) can be used in electrode 552X.

[0276] Example of Layer 105 configuration For example, an electron-injection material can be used for layer 105. Layer 105 can also be referred to as an electron-injection layer.

[0277] Specifically, a donor material can be used in layer 105. Alternatively, a composite material of a donor material and an electron-transporting material can be used in layer 105. Alternatively, an electride can be used in layer 105. This makes it easier to inject electrons, for example, from electrode 552X. Alternatively, not only materials with low work functions but also materials with high work functions can be used in electrode 552X. Alternatively, a material for electrode 552X can be selected from a wide range of materials, regardless of work function. Specifically, Al, Ag, ITO, silicon, or indium oxide-tin oxide containing silicon oxide can be used in electrode 552X. Alternatively, the driving voltage of the light-emitting device can be reduced.

[0278] [Substances with donor properties] For example, alkali metals, alkaline earth metals, rare earth metals, or compounds thereof (oxides, halides, carbonates, etc.) can be used as donor substances. Alternatively, organic compounds such as tetratianaphthalene (abbreviated as TTN), nickerosene, and decamethylnickerosene can also be used as donor substances.

[0279] 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, 8-hydroxyquinolinatolithium (abbreviated as Liq), etc.

[0280] As alkaline earth metal compounds (including oxides, halides, and carbonates), calcium fluoride (CaF2), etc., can be used.

[0281] [Example of composite material composition 1] Furthermore, materials composed of multiple types of substances can be used as materials with electron injection properties. For example, a substance with donor properties and a material with electron transport properties can be used as a composite material.

[0282] [Materials with electron transport properties] Metal complexes or organic compounds having a π-electron-deficient heteroaromatic ring skeleton can be used in electron-transporting materials. For example, an electron-transporting material that can be used in unit 103 can be used in a composite material.

[0283] [Example of composite material composition 2] Furthermore, a composite material can be made from a microcrystalline alkali metal fluoride and an electron-transporting material. Alternatively, a composite material can be made from a microcrystalline alkaline earth metal fluoride and an electron-transporting material. In particular, a composite material containing 50 wt% or more of alkali metal fluoride or alkaline earth metal fluoride can be suitably used. Alternatively, a composite material containing an organic compound having a bipyridine skeleton can be suitably used. This can reduce the refractive index of layer 105, or improve the external quantum efficiency of the light-emitting device.

[0284] [Example of composite material composition 3] For example, a composite material containing a first organic compound having lone pairs of electrons and a first metal can be used for layer 105. Furthermore, it is preferable that the sum of the number of electrons in the first organic compound and the first metal is odd. The molar ratio of the first metal to one 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.

[0285] As a result, the first organic compound, which has lone pairs of electrons, can interact with the first metal to form a Singly Occupied Molecular Orbital (SOMO). Furthermore, when injecting electrons from electrode 552X into layer 105, the barrier between them can be reduced. Additionally, because the first metal has poor reactivity with water or oxygen, the moisture resistance of the light-emitting device can be improved.

[0286] Furthermore, the spin density measured using electron spin resonance (ESR) is preferably 1 × 10⁻⁶. 16 spins / cm 3 The above is more comfortable 5x10 16 spins / cm 3 More preferably 1 × 10 17 spins / cm 3 The composite material described above can be used for layer 105.

[0287] [Organic compounds with lone pairs of electrons] For example, electron-transporting materials can be used in organic compounds containing lone pairs of electrons. For instance, compounds having electron-deficient heteroaromatic rings can be used. Specifically, compounds having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), or a triazine ring can be used. This allows for a reduction in the driving voltage of the light-emitting device.

[0288] Furthermore, it is preferable that the lowest unoccupied molecular orbital (LUMO) level of organic compounds containing lone pairs of electrons is between -3.6 eV and -2.3 eV. In general, the HOMO and LUMO levels of organic compounds can be estimated by methods such as cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, and inverse photoelectron spectroscopy.

[0289] For example, 4,7-diphenyl-1,10-phenanthroline (abbreviated as BPhen), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), and 2,4,6-tris[3'-(pyridine-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPPyTz) can be used in organic compounds containing lone pairs of electrons. NBPhen has a higher glass transition temperature (Tg) and superior heat resistance compared to BPhen.

[0290] Furthermore, copper phthalocyanine can be used, for example, in organic compounds that possess lone pairs of electrons. Note that copper phthalocyanine has an odd number of electrons.

[0291] [First Metal] For example, if the first organic compound having a lone pair of electrons has an even number of electrons, a composite material of a metal belonging to an odd group in the periodic table and the first organic compound can be used for layer 105.

[0292] For example, manganese (Mn), a metal of Group 7; cobalt (Co), a metal of Group 9; copper (Cu), silver (Ag), and gold (Au), metals of Group 11; and aluminum (Al) and indium (In), metals of Group 13, are all odd-numbered groups in the periodic table. Furthermore, elements of Group 11 have lower melting points compared to elements of Group 7 or 9, making them suitable for vacuum deposition. In particular, silver (Ag) is preferred due to its low melting point.

[0293] Furthermore, by using Ag in the electrode 552X and layer 105, the adhesion between layer 105 and electrode 552X can be improved.

[0294] Furthermore, if the number of electrons in the first organic compound, which has a lone pair of electrons, is odd, a composite material of the first metal and the first organic compound, which belong to an even group in the periodic table, can be used for layer 105. For example, iron (Fe), a metal in group 8, belongs to an even group in the periodic table.

[0295] [Electride] For example, a material obtained by adding a high concentration of electrons to a mixed oxide of calcium and aluminum can be used as an electron-injection material.

[0296] This embodiment can be appropriately combined with other embodiments shown in this specification.

[0297] (Embodiment 5) In this embodiment, the configuration of a display device according to one aspect of the present invention will be described with reference to Figure 5.

[0298] Figure 5A is a top view illustrating the configuration of a display device according to one embodiment of the present invention, and Figure 5B is a perspective view illustrating a part of Figure 5A.

[0299] <Example of display device configuration 5> The display device 700 described in this embodiment has a region 231, a functional layer 520, and a functional layer 510 (see Figures 5A, 5B, and 6A).

[0300] <Example configuration of area 231> Region 231 comprises a pair of pixels 703(i,j) (see Figure 5A). Region 231 has the function of displaying image information.

[0301] For example, region 231 comprises a set of 500 or more pixels per inch. It also comprises a group of 1,000 or more pixels per inch, preferably 5,000 or more, and more preferably 10,000 or more pixels per inch. This reduces the screen door effect, for example, when used in a goggle-type display device.

[0302] Furthermore, region 231 comprises multiple pixels. For example, region 231 comprises 7,600 or more pixels in the row direction and 4,300 or more pixels in the column direction. Specifically, it comprises 7,680 pixels in the row direction and 4,320 pixels in the column direction. This allows for the display of a detailed image.

[0303] 《Example of a set of 703 pixels (i,j)》 A pair of pixels 703(i,j) includes pixels 702R(i,j) and 702G(i,j) (see Figure 5B). Furthermore, a pair of pixels 703(i,j) also includes pixel 702B(i,j).

[0304] For example, multiple pixels that display colors with different hues can be used. Each of these multiple pixels can be referred to as a subpixel. Alternatively, multiple subpixels can be grouped together and referred to as a single pixel.

[0305] This allows for additive or subtractive color mixing of the colors displayed by the multiple pixels. Alternatively, it enables the display of hues that cannot be displayed by individual pixels.

[0306] Specifically, the pixel 702B(i,j) that displays blue, the pixel 702G(i,j) that displays green, and the pixel 702R(i,j) that displays red can be used as the pixel 703(i,j). In addition, pixels 702B(i,j), 702G(i,j), and 702R(i,j) can each be referred to as subpixels.

[0307] Furthermore, for example, a pixel that displays white, etc., can be used in addition to the above set of pixels 703(i,j). Also, a pixel that displays cyan, a pixel that displays magenta, and a pixel that displays yellow can be used in pixels 703(i,j).

[0308] Furthermore, for example, a pixel that emits infrared light can be used in addition to the above set for pixel 703(i,j). Specifically, a pixel that emits light including light with wavelengths between 650nm and 1000nm can be used for pixel 703(i,j).

[0309] 《Example configuration of pixel 702R(i,j)》 Pixel 702R(i,j) comprises a light-emitting device 550R(i,j) and a pixel circuit 530R(i,j) (see Figure 6A). The light-emitting device 550R(i,j) is electrically connected to the pixel circuit 530R(i,j). For example, the connection is made via an aperture 591R.

[0310] The pixel circuit 530R(i,j) is supplied with the first image signal.

[0311] 《Example configuration of pixel 702G(i,j)》 Pixel 702G(i,j) comprises a light-emitting device 550G(i,j) and a pixel circuit 530G(i,j). The light-emitting device 550G(i,j) is electrically connected to the pixel circuit 530G(i,j), for example, via an aperture 591G.

[0312] Furthermore, the pixel circuit 530G(i,j) is supplied with a second image signal.

[0313] <Example configuration of functional layer 520> The functional layer 520 includes pixel circuits 530G(i,j) and 530R(i,j).

[0314] The functional layer 520 is sandwiched between the light-emitting device 550R(i,j) and the functional layer 510. Furthermore, the functional layer 520 is sandwiched between the light-emitting device 550G(i,j) and the functional layer 510.

[0315] <Example configuration of functional layer 510> The functional layer 510 includes a drive circuit SD. The functional layer 510 also includes a drive circuit GD. For example, a single-crystal silicon substrate can be used for the functional layer 510.

[0316] 《Example configuration of the SD drive circuit》 The drive circuit SD generates a first image signal and a second image signal.

[0317] This allows the drive circuit SD to be placed on top of the functional layer 520, which includes the pixel circuits 530R(i,j) and 530G(i,j). Furthermore, the area outside the region 231 for displaying image information can be reduced. Additionally, the distance between the pixel circuit 530R(i,j) and the drive circuit SD can be shortened. Moreover, the transfer of the first image signal can be performed without delay. As a result, a novel display device with superior convenience, usefulness, and reliability can be provided.

[0318] Furthermore, the drive circuit SD has the function of supplying image signals and control signals, and the control signals include a first level and a second level. For example, the drive circuit SD is electrically connected to the conductive film S1g(j) to supply image signals and is electrically connected to the conductive film S2g(j) to supply control signals (see Figure 7).

[0319] Example configuration of the drive circuit GD The drive circuit GD has the function of supplying a first selection signal and a second selection signal. For example, the drive 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.

[0320] 《Example Configuration 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 Figure 7). Alternatively, the image signal can be supplied using the conductive film S1g(j). The operation of supplying the first selection signal and causing the pixel circuit 530G(i,j) to acquire an image signal can be called "writing".

[0321] 《Example Configuration 2 of Pixel Circuit 530G(i,j)》 The pixel circuit 530G(i,j) includes switch SW21, switch SW22, transistor M21, capacitor C21, and node N21 (see Figure 7). The pixel circuit 530G(i,j) also includes node N22, capacitor C22, and switch SW23.

[0322] Transistor M21 comprises a gate electrode electrically connected to node N21, a first electrode electrically connected to light-emitting device 550G(i,j), and a second electrode electrically connected to conductive film ANO.

[0323] The switch SW21 comprises a first terminal electrically connected to node N21, a second terminal electrically connected to conductive film S1g(j), and a gate electrode that has the function of controlling a conduction state or a non-conduction state based on the potential of conductive film G1(i).

[0324] The switch SW22 comprises a first terminal electrically connected to the conductive film S2g(j), and a gate electrode that has the function of controlling a conduction state or a non-conduction state based on the potential of the conductive film G2(i).

[0325] Capacitor C21 comprises a conductive film electrically connected to node N21 and a conductive film electrically connected to the second electrode of switch SW22.

[0326] This allows the image signal to be stored in node N21. Alternatively, the potential of node N21 can be changed using switch SW22. Or, the intensity of the light emitted by the light-emitting device 550G(i,j) can be controlled using the potential of node N21.

[0327] 《Example configuration of transistor M21》 Bottom-gate or top-gate transistors can be used in the functional layer 520. Specifically, transistors can be used as switches.

[0328] The transistor comprises a semiconductor film 508, a conductive film 504, a conductive film 507A, and a conductive film 507B (see Figure 6B). The transistor is formed, for example, on an insulating film 501C.

[0329] The semiconductor film 508 includes a region 508A that is electrically connected to the conductive film 507A, and a region 508B that is electrically connected to the conductive film 507B. The semiconductor film 508 includes a region 508C between regions 508A and 508B.

[0330] The conductive film 504 has a region that overlaps with region 508C, and the conductive film 504 has the function of a gate electrode.

[0331] The insulating film 506 comprises a region sandwiched between the semiconductor film 508 and the conductive film 504. The insulating film 506 functions as a gate insulating film.

[0332] Conductive film 507A has either the function of a source electrode or a drain electrode, and conductive film 507B has either the function of a source electrode or a drain electrode. Furthermore, conductive film 507A is electrically connected to conductive film 512A, and conductive film 507B is electrically connected to conductive film 512B.

[0333] Furthermore, the conductive film 524 can be used in a transistor. The conductive film 524 has a region in which the semiconductor film 508 is sandwiched between it 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. The insulating film 518 covers the transistor, and the insulating film 501C is sandwiched between the insulating film 501B and the insulating film 501D. The insulating film 516 also comprises insulating film 516A and insulating film 516B.

[0334] Furthermore, in the process of forming the semiconductor film used for the transistors in the pixel circuit, the semiconductor film used for the transistors in the drive circuit can also be formed. For example, a semiconductor film with the same composition as the semiconductor film used for the transistors in the pixel circuit can be used in the drive circuit.

[0335] 《Example 1 of semiconductor film 508 configuration》 For example, a semiconductor containing group 14 elements can be used for the semiconductor film 508. Specifically, a semiconductor containing silicon can be used for the semiconductor film 508.

[0336] [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 makes it easier to enlarge the functional panel.

[0337] [Polysilicon] For example, polysilicon can be used for the semiconductor film 508. Specifically, low-temperature polysilicon (LTPS (Low Temperature Poly Silicon)) can be used for the semiconductor film 508. This allows for, for example, a higher field-effect mobility of the transistor compared to a transistor using hydrogenated amorphous silicon for the semiconductor film 508. Alternatively, for example, the driving capability can be increased compared to a transistor using hydrogenated amorphous silicon for the semiconductor film 508. Alternatively, for example, the aperture ratio of the pixels can be improved compared to a transistor using hydrogenated amorphous silicon for the semiconductor film 508.

[0338] Alternatively, for example, the reliability of the transistor can be improved compared to a transistor using hydrogenated amorphous silicon as the semiconductor film 508.

[0339] Alternatively, the temperature required for transistor fabrication can be lowered compared to, for example, transistors using single-crystal silicon.

[0340] Alternatively, the semiconductor film used for the transistors in the drive circuit can be formed using the same process as the semiconductor film used for the transistors in the pixel circuit. Alternatively, the drive circuit can be formed on the same substrate as the substrate on which the pixel circuit is formed. Alternatively, the number of components constituting the electronic device can be reduced.

[0341] [Single-crystal silicon] For example, single-crystal silicon can be used for the semiconductor film 508. This allows for higher resolution than, for example, a functional panel using hydrogenated amorphous silicon for the semiconductor film 508. Alternatively, it is possible to provide a functional panel with less display unevenness than a functional panel using polysilicon for the semiconductor film 508. Alternatively, for example, smart glasses or a head-mounted display can be provided.

[0342] 《Example 2 of the configuration of semiconductor film 508》 For example, a metal oxide can be used for the semiconductor film 508. This allows the pixel circuit to hold the image signal for a longer time compared to a pixel circuit using a transistor with silicon as the semiconductor film, for example. Specifically, the 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 by the user of the information processing device can be reduced. In addition, power consumption associated with operation can be reduced.

[0343] For example, transistors using oxide semiconductors can be utilized. Specifically, oxide semiconductors containing indium, oxide semiconductors containing indium, gallium, and zinc, or oxide semiconductors containing indium, zinc, and tin can be used as semiconductor films.

[0344] For example, a transistor with a smaller leakage current in the off state than a transistor using silicon as the semiconductor film can be used. Specifically, a transistor using oxide semiconductor as the semiconductor film can be used as a switch, etc. This allows the potential of the floating node to be maintained for a longer time than in a circuit using a silicon transistor as a switch.

[0345] Transistors using metal oxides in the semiconductor film (also known as OS transistors) have extremely high field-effect mobility compared to transistors using amorphous silicon. Furthermore, OS transistors exhibit remarkably low source-drain leakage current (hereinafter referred to as off-current) in the off state, allowing them to retain charge stored in a capacitor connected in series with the transistor for extended periods. Additionally, the application of OS transistors can reduce the power consumption of display devices.

[0346] Furthermore, the off-current value of an OS transistor per 1 μm channel width at room temperature is 1 aA (1 × 10⁻¹⁰). -18 A) Below, 1zA(1×10 -21 A) Less than or equal to 1yA(1×10 -24 A) It can be less than or equal to the following. Note that the off-current value of a Si transistor per 1 μm of channel width at room temperature is 1 fA (1 × 10⁻¹⁰). -15 A) More than 1pA (1×10 -12 A) The answer is as follows. Therefore, it can be said that the off-current of an OS transistor is about 10 orders of magnitude lower than that of a Si transistor.

[0347] Furthermore, to increase the luminescence brightness of the light-emitting device included in the pixel circuit, it is necessary to increase the amount of current flowing through the light-emitting device. To achieve this, it is necessary to increase the source-drain voltage of the drive transistor included in the pixel circuit. Compared to Si transistors, OS transistors have a higher breakdown voltage between the source and drain, so a higher voltage can be applied between the source and drain of an OS transistor. As a result, by using an OS transistor as the drive transistor in the pixel circuit, the amount of current flowing through the light-emitting device can be increased, thereby increasing the luminescence brightness of the light-emitting device.

[0348] Furthermore, when the transistor operates in the saturation region, OS transistors exhibit smaller changes in source-drain current in response to changes in gate-source voltage compared to Si transistors. Therefore, by using OS transistors as driving transistors in the pixel circuit, the current flowing between the source and drain can be precisely controlled by changes in gate-source voltage, thereby controlling the amount of current flowing to the light-emitting device. This allows for a wider range of tonal gradations in the pixel circuit.

[0349] Furthermore, in terms of the saturation characteristics of the current flowing when a transistor operates in the saturation region, OS transistors can supply a more stable current (saturation current) than Si transistors, even when the source-drain voltage gradually increases. Therefore, by using OS transistors as driving transistors, for example, a stable current can be supplied to a light-emitting device even if there are variations in the current-voltage characteristics of the light-emitting device containing EL material. In other words, when operating in the saturation region, the source-drain current remains almost unchanged even when the source-drain voltage is increased, thus stabilizing the luminescence brightness of the light-emitting device.

[0350] As described above, by using OS transistors in the drive transistors included in the pixel circuit, it is possible to achieve "suppression of black level floating," "increase in luminescence brightness," "multi-gradation," and "suppression of variations in light-emitting devices."

[0351] 《Example 3 of the configuration of semiconductor film 508》 For example, compound semiconductors can be used as semiconductors in transistors. Specifically, semiconductors containing gallium arsenide can be used.

[0352] For example, organic semiconductors can be used as semiconductors in transistors. Specifically, organic semiconductors containing polyacenes or graphene can be used as semiconductor films.

[0353] 《Example 3 of the Pixel Circuit 530G(i,j) Configuration》 For example, by using both LTPS transistors and OS transistors, a display device with low power consumption and high driving capability can be realized. Furthermore, a configuration combining LTPS transistors and OS transistors is sometimes referred to as LTPO. In a more preferable example, it is preferable to apply OS transistors to transistors that function as switches to control conduction and non-conduction between wires, and LTPS transistors to transistors that control current.

[0354] For example, one of the transistors in a pixel circuit functions as a transistor for controlling the current flowing to the light-emitting device and can be called a drive transistor. One of the source and drain of the drive transistor is electrically connected to the pixel electrode of the light-emitting device. It is preferable to use an LTPS transistor for this drive transistor. This allows the current flowing to the light-emitting device in the pixel circuit to be increased.

[0355] On the other hand, another transistor in the pixel circuit functions as a switch to control the selection and deselection of pixels, and can also be called a selection transistor. The gate of the selection transistor is electrically connected to the gate line, and one of the source and drain is electrically connected to the source line (signal line). It is preferable to use an OS transistor for the selection transistor. This allows the pixel gradation to be maintained even when the frame frequency is significantly reduced (e.g., 1 fps or less), and thus power consumption can be reduced by stopping the driver when displaying still images.

[0356] 《Example 4 of the Pixel Circuit 530G(i,j) Configuration》 Furthermore, the transistor configuration used in the display panel can be appropriately selected according to the screen size of the display panel. For example, when using single-crystal Si transistors as the display panel transistors, it can be applied to screen sizes with a diagonal size of 0.1 inches to 3 inches. When using LTPS transistors as the display panel transistors, it can be applied to screen sizes with a diagonal size of 0.1 inches to 30 inches, preferably 1 inch to 30 inches. When using LTPO transistors in the display panel, it can be applied to screen sizes with a diagonal size of 0.1 inches to 50 inches, preferably 1 inch to 50 inches. When using OS transistors as the display panel transistors, it can be applied to screen sizes with a diagonal size of 0.1 inches to 200 inches, preferably 50 inches to 100 inches.

[0357] Furthermore, single-crystal Si transistors are extremely difficult to enlarge due to the size of the single-crystal Si substrate. Similarly, LTPS transistors require laser crystallization during the manufacturing process, making it difficult to accommodate larger screen sizes (typically exceeding 30 inches diagonally). On the other hand, OS transistors are not subject to the constraints of using laser crystallization during the manufacturing process, or can be manufactured at relatively low process temperatures (typically below 450°C), making them suitable for relatively large display panels (typically between 50 and 100 inches diagonally). LTPO transistors can be applied to display panel sizes in the range between those using LTPS and OS transistors (typically between 1 and 50 inches diagonally).

[0358] 《Example configuration of the 550G(i,j) light-emitting device》 The light-emitting device 550G(i,j) is electrically connected to the pixel circuit 530G(i,j) (see Figure 7). The light-emitting device 550G(i,j) operates based on the potential of node N21.

[0359] The light-emitting device 550G(i,j) comprises an electrode 551G(i,j) and an electrode 552G(i,j). Electrode 551G(i,j) is electrically connected to the pixel circuit 530G(i,j), and electrode 552G(i,j) is electrically connected to the conductive film VCOM2.

[0360] For example, organic electroluminescent elements, inorganic electroluminescent elements, light-emitting diodes, or QDLEDs (Quantum Dot LEDs) can be used as the light-emitting device 550G(i,j).

[0361] <Example of display device configuration 6> The display device 700 also has terminal 519B and conductive film VCOM2 (see Figure 5A).

[0362] Terminal 519B is electrically connected to the functional layer 510. The display device can send and receive signals to and from the outside of the display device via terminal 519B.

[0363] Furthermore, the display device 700 has an insulating film 705 and a substrate 770 (see Figure 6A).

[0364] The insulating film 705 is 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.

[0365] The light-emitting devices 550R(i,j) and 550G(i,j) are sandwiched between the substrate 770 and the functional layer 520. The display device displays information through the substrate 770 (see Figure 6A). In other words, the light-emitting device 550G(i,j) emits light in the direction where the functional layer 520 is not located. The light-emitting device 550G(i,j) can also be described as a top-emission type light-emitting device.

[0366] This embodiment can be appropriately combined with other embodiments shown in this specification.

[0367] (Embodiment 6) In this embodiment, a display device and a display system, which are aspects of the present invention, will be described with reference to Figures 8 to 13.

[0368] Figure 8 is a block diagram illustrating the configuration of a display device according to one embodiment of the present invention.

[0369] Figure 9 is a block diagram illustrating the configuration of the display unit shown in Figure 8.

[0370] Figure 10 is a block diagram illustrating the configuration of a display device according to one embodiment of the present invention.

[0371] Figure 11 is a circuit diagram illustrating the pixel configuration shown in Figure 10.

[0372] Figure 12 is a block diagram illustrating the configuration of a display device according to one embodiment of the present invention.

[0373] Figure 13A is a flowchart of the correction method, and Figure 13B is a schematic diagram illustrating the correction method.

[0374] <Example of display device configuration 7> Next, Figure 8 shows a block diagram illustrating the various components of the display device 10. The display device includes a drive circuit 40, a function circuit 50, and a display unit 60.

[0375] 《Example 1 of the configuration of the drive circuit 40》 The drive circuit 40 includes, for example, a gate driver 41 and a source driver 42. The gate driver 41 has the function of driving multiple gate lines GL for outputting signals to pixel circuits 62R, 62G, and 62B. The source driver 42 has the function of driving multiple source lines SL for outputting signals to pixel circuits 62R, 62G, and 62B. The drive circuit 40 also supplies voltage to the pixel circuits 62R, 62G, and 62B via multiple wires for displaying signals.

[0376] 《Example 1 of the configuration of the functional circuit 50》 The functional circuit 50 has a CPU 51, which can be used for data arithmetic processing. The CPU 51 also has a CPU core 53. The CPU core 53 has a flip-flop 80 for temporarily holding data used in 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 the data (backup data) from the scan flip-flops to and from the backup circuit 82.

[0377] 《Display section 60》 Figures 9 and 8 illustrate an example of the arrangement of the backup circuit 82 and the sub-pixels, pixel circuits 62R, 62G, and 62B, within the display unit 60.

[0378] Figure 9 illustrates a configuration in the display unit 60 in which multiple pixels 61 are arranged in a matrix. Each pixel 61 has pixel circuits 62R, 62G, and 62B, as well as a backup circuit 82. As described above, both the backup circuit 82 and the pixel circuits 62R, 62G, and 62B can be made of OS transistors and can therefore be arranged within the same pixel.

[0379] The display unit 60 has multiple pixels 61, each equipped with pixel circuits 62R, 62G, 62B, and a backup circuit 82. As explained in Figure 9, the backup circuit 82 does not necessarily need to be placed within the repeating unit of pixel 61. It can be freely arranged depending on the shape of the display unit 60, the shape of the pixel circuits 62R, 62G, 62B, etc.

[0380] <Example of display device configuration 8> Figure 10 is a schematic block diagram showing an example configuration of a display device 10, which is a display device according to one aspect of the present invention. The display device 10 has a layer 20 and a layer 30, and the layer 30 can be laminated, for example, on top of the layer 20. An interlayer insulator or a conductor for making an electrical connection between different layers can be provided between the layer 20 and the layer 30.

[0381] 《Layer 20》 The transistor provided in layer 20 can be, for example, a transistor having silicon in the channel formation region (also called a Si transistor), or a transistor having single-crystal silicon in the channel formation region. In particular, using a transistor having single-crystal silicon in the channel formation region as the transistor provided in layer 20 allows for a large on-current of the transistor. Therefore, it is preferable because the circuit of layer 20 can be driven at high speed. Furthermore, since Si transistors can be formed with microfabrication such as a channel length of 3 nm to 10 nm, they can be used in a display device 10 equipped with an accelerator such as a CPU or GPU, an application processor, etc.

[0382] Layer 20 is provided with a drive circuit 40 and a functional circuit 50. The Si transistors in layer 20 can have a large on-current. Therefore, each circuit can be driven at high speed.

[0383] 《Example 2 of the drive circuit 40 configuration》 The drive circuit 40 includes gate line drive circuits, source line drive circuits, etc., for driving the pixel circuits 62R, 62G, and 62B. For example, the drive circuit 40 includes gate line drive circuits and source line drive circuits for driving the pixels 61 of the display unit 60. By arranging the drive circuit 40 on a layer 20 different from the layer 30 on which the display is provided, the area occupied by the display unit on 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, etc., which function as an interface for receiving data such as image data from outside the display device 10. The Si transistors on layer 20 can have a high on-current. Depending on the operating speed of each circuit, the channel length or channel width of the Si transistors may be varied.

[0384] 《Layer 30》 The transistor provided in layer 30 can be, for example, an OS transistor. In particular, it is preferable to use an OS transistor having an oxide containing at least one of indium, element M (where element M is aluminum, gallium, yttrium, or tin), and zinc in the channel formation region. Such an OS transistor has the characteristic of having a very low off-current. Therefore, it is preferable to use an OS transistor as a transistor provided in the pixel circuit of the display unit in particular, because it can retain the analog data written to the pixel circuit for a long period of time.

[0385] Layer 30 is provided with a display unit 60 having multiple pixels 61. Each pixel 61 is provided with pixel circuits 62R, 62G, and 62B that control the emission of red, green, and blue light. Pixel circuits 62R, 62G, and 62B function as sub-pixels of pixel 61. Since pixel circuits 62R, 62G, and 62B have OS transistors, they can retain analog data written to the pixel circuits for a long period of time. Each pixel 61 in layer 30 is also provided with a backup circuit 82. The backup circuit may also be called a storage circuit or memory circuit. The backup circuit inputs and outputs data (backup data BD) from a scan flip-flop to a flip-flop 80.

[0386] 《Example of Pixel Circuit Configuration 1》 Figures 11A and 11B show examples of the configuration of the pixel circuit 62 applicable to the pixel circuits 62R, 62G, and 62B, and the light-emitting element 70 connected to the pixel circuit 62. Figure 11A is a diagram showing the connections of each element, and Figure 11B is a diagram schematically showing the vertical relationship between the drive circuit 40, the pixel circuit 62, and the light-emitting element 70.

[0387] In this specification, the term "element" may sometimes be replaced with "device." For example, display elements, light-emitting elements, and liquid crystal elements may be replaced with, for example, display devices, light-emitting devices, and liquid crystal devices.

[0388] The pixel circuit 62 shown as an example in Figures 11A and 11B comprises a switch SW21, a switch SW22, a transistor M21, and a capacitor C21. Switches SW21 and SW22, and transistor M21 can be composed of OS transistors. It is preferable that each OS transistor of switch SW21, switch SW22, and transistor M21 is equipped with a back gate electrode. In this case, the back gate electrode can be configured to receive the same signal as the gate electrode, or to receive a different signal from the gate electrode.

[0389] Transistor M21 comprises a gate electrode electrically connected to switch SW21, a first electrode electrically connected to light-emitting element 70, and a second electrode electrically connected to conductive film ANO. Conductive film ANO is wiring that provides a potential for supplying current to light-emitting element 70.

[0390] The switch SW21 comprises a first terminal electrically connected to the gate electrode of transistor M21, a second terminal electrically connected to the source line SL, and a gate electrode that has the function of controlling a conduction state or a non-conduction state based on the potential of the gate line GL1.

[0391] The switch SW22 comprises a first terminal electrically connected to wiring V0, a ​​second terminal electrically connected to the light-emitting element 70, and a gate electrode that has the function of controlling a conduction state or a non-conduction state based on the potential of the gate wire GL2. Wiring V0 is wiring for supplying a reference potential and wiring for outputting the current flowing through the pixel circuit 62 to the drive circuit 40 or the function circuit 50.

[0392] Capacitor C21 comprises a conductive film electrically connected to the gate electrode of transistor M21 and a conductive film electrically connected to the second electrode of switch SW22.

[0393] The light-emitting element 70 comprises a first electrode electrically connected to the first electrode of the transistor M21, and a second electrode electrically connected to the conductive film VCOM. The conductive film VCOM is a wiring that provides a potential for supplying current to the light-emitting element 70.

[0394] This allows the intensity of light emitted by the light-emitting element 70 to be controlled according to the image signal applied to the gate electrode of transistor M21. Furthermore, the amount of current flowing through the light-emitting element 70 can be increased by the reference potential of the wiring V0 provided via switch SW22. By monitoring the amount of current flowing through wiring V0 with an external circuit, the amount of current flowing through the light-emitting element can be estimated. This allows for the detection of pixel defects and other issues.

[0395] 《Example of Pixel Circuit Configuration 2》 In the configuration shown as an example in Figure 11B, the wiring electrically connecting the pixel circuit 62 and the drive circuit 40 can be shortened, thereby reducing the wiring resistance. As a result, data can be written at high speed, and the display device 10 can be driven at high speed. This allows for a sufficient frame duration even with a large number of pixels 61 in the display device 10, thus increasing the pixel density of the display device 10. Furthermore, increasing the pixel density of the display device 10 improves the resolution of the image displayed by the display device 10. For example, the pixel density of the display device 10 can be set to 1000 ppi or more, or 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, and can be suitably applied to electronic devices such as HMDs where the distance between the display unit and the user is close.

[0396] In Figure 11B, the gate line GL1, gate line GL2, conductive film VCOM, wiring V0, conductive film ANO, and source line SL are shown to be supplied via wiring from the drive circuit 40 below the pixel circuit 62, but the present invention is not limited to this. For example, the wiring that supplies the signals and voltages of the drive circuit 40 may be routed to the outer periphery of the display unit 60 and electrically connected to each pixel circuit 62 arranged in a matrix on layer 30. In this case, it is effective to provide the gate driver 41 of the drive circuit 40 on layer 30. That is, it is effective to use an OS transistor for the gate driver 41. It is also effective to provide part of the function of the source driver 42 of the drive circuit 40 on layer 30. For example, it is effective to provide a demultiplexer on layer 30 that distributes the signals output by the source driver 42 to each source line. It is also effective to use an OS transistor for the demultiplexer.

[0397] Backup circuit 82 The backup circuit 82 is preferably a memory having an OS transistor. A backup circuit composed of an OS transistor has advantages such as being able to suppress the voltage drop corresponding to the data being backed up due to the OS transistor's characteristic of having an extremely small off-current, and consuming almost no power to retain data. The backup circuit 82 having an OS transistor can be provided in a display unit 60 where multiple pixels 61 are arranged. Figure 10 illustrates how the backup circuit 82 is provided for each pixel 61.

[0398] The backup circuit 82, composed of OS transistors, can be stacked with the layer 20 having Si transistors. The backup circuit 82 may be arranged in a matrix similar to the subpixels within the pixel 61, or it may be arranged for each of multiple pixels. In other words, the backup circuit 82 can be placed within the layer 30 without being constrained by the arrangement of the pixels 61. Therefore, it is possible to increase the degree of freedom of the display unit / circuit layout, and to place it without increasing the circuit area, thereby increasing the memory capacity of the backup circuit 82 required for calculation processing.

[0399] <Example of display device configuration 9> Figure 12 shows modified examples of each configuration of the display device 10 described above.

[0400] The block diagram of the display device 10A shown in Figure 12 corresponds to a configuration in which an accelerator 52 is added to the functional circuit 50 of the display device 10 in Figure 8.

[0401] The accelerator 52 functions as a dedicated arithmetic circuit for the multiply-accumulate operation of the artificial neural network (NN). The calculations performed using the accelerator 52 can include processes such as upconverting display data to correct image contours. Furthermore, power consumption can be reduced by configuring the CPU 51 to be power-gated while the accelerator 52 is performing calculations.

[0402] <Example of display system configuration> Furthermore, in one embodiment of the present invention, the display device can have a pixel circuit and a functional circuit stacked on top of each other. Therefore, a functional circuit located below the screen circuit can be used to detect defective pixels. By using this information about defective pixels, display defects caused by defective pixels can be corrected, and a normal display can be achieved.

[0403] Some of the correction methods illustrated below may be performed by circuits located outside the display device. Furthermore, some of the correction methods may be performed by the functional circuits 50 of the display device 10.

[0404] The following shows examples of more specific correction methods. Figure 13A is a flowchart illustrating the correction method described below.

[0405] First, the correction operation is started in step S1 "Start".

[0406] Next, in step S2, "Readout of pixel current," the pixel current is read. For example, each pixel can be driven to output current to the monitor line electrically connected to the pixel.

[0407] Next, in step S3 "voltage conversion," the read current is converted into a voltage. At this point, if digital signals will be handled in subsequent processing, the current can be converted into digital data in step S3. For example, analog data can be converted into digital data using an analog-to-digital converter (ADC).

[0408] Next, in step S4 "Pixel Parameter Acquisition," the pixel parameters of each pixel are acquired based on the acquired data. Examples of pixel parameters include the threshold voltage or field-effect mobility of the drive transistor, the threshold voltage of the light-emitting element, and the current value at a predetermined voltage.

[0409] Next, in step S5 "Anomaly Determination," each pixel is determined to be abnormal or not based on its pixel parameters. For example, if the value of a pixel parameter exceeds (or falls below) a predetermined threshold, that pixel is identified as an abnormal pixel.

[0410] Abnormal pixels include dark spots, which are significantly lower in brightness relative to the input data potential, and bright spots, which are significantly higher in brightness.

[0411] In step S5, the address of the abnormal pixel and the type of defect can be identified and obtained.

[0412] Next, in step S6 "Correction Processing," the correction processing is performed.

[0413] An example of the correction process will be explained using Figure 13B. Figure 13B schematically shows a 3x3 pixel array. Here, the central pixel is assumed to be pixel 61D, which is a dark spot defect. Figure 13B schematically shows a state where pixel 61D is off, and the surrounding pixels 61N are lit at a predetermined brightness.

[0414] A dark spot defect is a defect in which, even if a correction is applied to increase the data potential input to the pixel, the pixel's brightness is unlikely to reach normal levels. Therefore, as shown in Figure 13B, a correction is applied to increase the brightness of the pixels 61N surrounding the dark spot defect pixel 61D. This allows for the display of a normal image even when a dark spot defect occurs.

[0415] In the case of bright pixel defects, the brightness of the surrounding pixels can be reduced to make the bright pixel defects less noticeable.

[0416] In particular, with high-resolution display devices (e.g., 1000 ppi or higher), it is difficult to distinguish and visually identify each individual pixel. Therefore, using correction methods that compensate for abnormal pixels with surrounding pixels is especially effective.

[0417] On the other hand, it is preferable to correct abnormal pixels such as dark spots and bright spots by not inputting data potentials.

[0418] In this way, correction parameters can be set for each pixel. By applying the correction parameters to the input image data, corrected image data can be generated to display an optimal image on the display device 10.

[0419] Furthermore, because variations exist in pixel parameters not only in abnormal pixels and the pixels surrounding them, but also in pixels that were not identified as abnormal, when an image is displayed, inconsistencies caused by these variations may be visible. Therefore, for pixels that were not identified as abnormal, correction parameters can be set to cancel (level out) the variations in pixel parameters. For example, a reference value can be set based on the median or average value of the pixel parameters for some or all pixels, and a correction value can be set as the correction parameter for a given pixel to cancel out the difference from the reference value for the pixel parameters of that pixel.

[0420] Furthermore, for pixels surrounding an abnormal pixel, it is preferable to set correction data that takes into account both a correction amount to compensate for the abnormal pixel and a correction amount to cancel out variations in pixel parameters.

[0421] Next, in step S7, the correction operation is terminated.

[0422] From this point forward, the image can be displayed based on the correction parameters obtained through the above correction operation and the input image data.

[0423] Furthermore, a neural network may be used as one of the correction operations. When calculations based on an artificial neural network are performed in the display correction system described above, the configuration involves repeatedly performing sum-of-accumulate operations. The calculations using the accelerator 52 can perform corrections caused by the display defects described above. Furthermore, power consumption can be reduced by configuring the CPU 51 to be power-gated while the calculation processing by the accelerator 52 is being performed. As for the neural network, for example, the correction parameters can be determined based on inference results obtained by machine learning. For example, they can be estimated by performing calculations based on artificial neural networks such as deep neural networks (DNN), convolutional neural networks (CNN), recurrent neural networks (RNN), autoencoders, deep Boltzmann machines (DBM), and deep belief networks (DBN). When correction parameters are determined using a neural network, high-precision correction can be performed so that abnormal pixels are not noticeable, even without using a detailed correction algorithm.

[0424] The above is an explanation of the correction method.

[0425] Furthermore, the CPU 51, as described above, can continuously retain data in the process of correcting the current flowing to pixels by the display correction system as backup data. Therefore, it is particularly effective when performing computationally intensive processing such as calculations based on artificial neural networks. By making the CPU 51 function as an application processor, it is also possible to reduce display defects and lower power consumption by combining it with features such as variable frame frequency driving.

[0426] This embodiment can be appropriately combined with descriptions of other embodiments.

[0427] (Embodiment 7) In this embodiment, an example of the cross-sectional configuration of a display device 10, which is one aspect of the present invention, will be described.

[0428] <Example of display device configuration 10> Figure 14 is a cross-sectional view showing an example configuration of the display device 10. The display device 10 has an insulator 421 and a substrate 770, and the insulator 421 and the substrate 770 are bonded together by a sealing material 712. It is preferable to use OS transistors for the pixel circuit. Furthermore, at least a part of the drive circuit may be made up of OS transistors. Also, at least a part of the functional circuit may be made up of OS transistors. Also, at least a part of the drive circuit may be external. Also, at least a part of the functional circuit may be external.

[0429] Insulators 421, 214, and 216 Various insulating substrates such as glass substrates and sapphire substrates can be used as the insulator 421. An insulator 214 is provided on the insulator 421, and an insulator 216 is provided on the insulator 214.

[0430] Insulators 222, 224, 254, 280, 274, and 281. Insulators 222, 224, 254, 280, 274, and 281 are provided on the insulator 216.

[0431] Insulators 421, 214, 280, 274, and 281 may function as interlayer films and as planarizing films that cover the uneven surface beneath them.

[0432] Insulator 361 An insulator 361 is provided on an insulator 281. Conductors 317 and 337 are embedded in the insulator 361. Here, the height of the upper surface of the conductor 337 and the height of the upper surface of the insulator 361 can be made to be approximately the same.

[0433] Insulator 363 An insulator 363 is provided on the conductor 337 and on the insulator 361. Conductors 347, 353, 355, and 357 are embedded in the insulator 363. Here, the height of the upper surfaces of conductors 353, 355, and 357 can be made to be approximately the same as the height of the upper surface of the insulator 363.

[0434] Conductors 341, 343, and 351 are embedded in the insulator 363. Here, the height of the upper surface of conductor 351 and the height of the upper surface of insulator 363 can be made to be approximately the same.

[0435] The insulators 361 and 363 may function as interlayer films and as planar films that cover the uneven surface beneath them. For example, the upper surface of the insulator 363 may be planarized by a planarization treatment such as chemical mechanical polishing (CMP) to improve its flatness.

[0436] 《Connecting electrode 760》 Connecting electrodes 760 are provided on the conductor 353, conductor 355, conductor 357, and insulator 363. An anisotropic conductor 780 is provided so as to be electrically connected to the connecting electrodes 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.

[0437] In Figure 14, three conductors, conductor 353, conductor 355, and conductor 357, are shown as conductors that have the function of electrically connecting the connecting electrode 760 and the conductor 347, but the present invention is not limited to these. There may be one, two, or four or more conductors that have the function of electrically connecting the connecting electrode 760 and the conductor 347. By providing multiple conductors that have the function of electrically connecting the connecting electrode 760 and the conductor 347, the contact resistance can be reduced.

[0438] Transistor 750 A transistor 750 is provided on the insulator 214. The transistor 750 can be a transistor provided on layer 30 as shown in Embodiment 6. For example, it can be a transistor provided on pixel circuit 62. An OS transistor can preferably be used as the transistor 750. OS transistors have the characteristic of having an extremely small off-current. Therefore, the retention time of image data, etc. can be extended, and the frequency of refresh operations can be reduced. Therefore, the power consumption of the display device 10 can be reduced.

[0439] Furthermore, transistor 750 can be a transistor provided in the backup circuit 82. Preferably, an OS transistor can be used for transistor 750. OS transistors have the characteristic of having an extremely small off-current. Therefore, the data held by the flip-flop can be retained even during periods when the power supply voltage sharing is stopped. This allows for normally-off operation of the CPU (an operation that intermittently stops the power supply voltage). Thus, the power consumption of the display device 10 can be reduced.

[0440] Conductors 301a and 301b are embedded in insulators 254, 280, 274, and 281, respectively. Conductor 301a is electrically connected to either the source or drain of transistor 750, and conductor 301b is electrically connected to the other source or drain of transistor 750. Here, the height of the upper surfaces of conductors 301a and 301b can be made to be approximately the same as the height of the upper surface of insulator 281.

[0441] Conductors 311, 313, 331, capacitor 790, 333, and 335 are embedded in the insulator 361. Conductors 311 and 313 are electrically connected to the transistor 750 and function as wiring. Conductors 333 and 335 are electrically connected to the capacitor 790. Here, the height of the upper surfaces of conductors 331, 333, and 335 can be made to be approximately the same as the height of the upper surface of the insulator 361.

[0442] 《Capacity 790》 As shown in Figure 14, 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. In other words, the capacitor 790 has a laminated structure in which an insulator 323, which functions as a dielectric, is sandwiched between a pair of electrodes. Although Figure 14 shows an example in which the capacitor 790 is provided on an insulator 281, the capacitor 790 may be provided on an insulator different from the insulator 281.

[0443] Figure 14 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 the lower electrode 321 are formed in the same layer. Furthermore, it 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. In addition, it shows an example in which conductors 351, 353, 355, and 357 are formed in the same layer. By forming multiple conductors in the same layer, the manufacturing process of the display device 10 can be simplified, thereby reducing the manufacturing cost of the display device 10. Note that these may be formed in different layers and may be made of different types of materials.

[0444] 《Light-emitting element 70》 The display device 10 shown in Figure 14 has a light-emitting element 70. The light-emitting element 70 has a conductor 772, an EL layer 786, and a conductor 788. The EL layer 786 has an organic compound or an inorganic compound such as a quantum dot.

[0445] Materials that can be used in organic compounds include fluorescent materials or phosphorescent materials. Materials that can be used in quantum dots include colloidal quantum dot materials, alloy-type quantum dot materials, core-shell type quantum dot materials, and core-type quantum dot materials.

[0446] For example, the brightness of the display device 10 is 500 cd / m². 2 Preferably 1000 cd / m² 2 More than 10000cd / m 2 More preferably, 2000 cd / m² 2 More than 5000cd / m 2 The following is possible:

[0447] The conductor 772 is electrically connected to the other side of the source or drain of the transistor 750 via conductors 351, 341, 331, 313, and 301b. The conductor 772 is formed on the insulator 363 and functions as a pixel electrode.

[0448] The conductor 772 can be made of a material that is transparent to visible light or a material that is reflective to visible light. As a transparent material, for example, an oxide material containing indium, zinc, tin, etc., may be used. As a reflective material, for example, a material containing aluminum, silver, etc., may be used.

[0449] Furthermore, the light-emitting element 70 has a light-transmitting conductor 788, and can be a top-emission type light-emitting element. The light-emitting element 70 may also have a bottom-emission structure that emits light towards the conductor 772, or a dual-emission structure that emits light towards both the conductor 772 and the conductor 788.

[0450] The light-emitting element 70 can have a microcavity structure. This allows it to extract light of a predetermined color (e.g., RGB), enabling the display device 10 to display high-brightness images. It also reduces the power consumption of the display device 10.

[0451] 《Light-shielding layer 738, insulator 734》 On the substrate 770 side, a light-shielding layer 738 and an insulator 734 in contact with them are provided. The light-shielding layer 738 has the function of blocking light emitted from adjacent areas. Alternatively, the light-shielding layer 738 has the function of preventing ambient light from reaching the transistor 750, etc.

[0452] Insulator 730 In the display device 10 shown in Figure 14, an insulator 730 is provided on the insulator 363. Here, the insulator 730 can be configured to cover a part of the conductor 772. In this embodiment, the configuration with an insulator 730 is illustrated, but the embodiment is not limited to this. For example, a configuration without an insulator 730 may be used. In the case of not providing an insulator 730, the opening of the display device can be raised, which is preferable.

[0453] The light-shielding layer 738 is provided so as to have an area that overlaps 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 a sealing layer 732.

[0454] 《Structure 778》 Furthermore, the structure 778 is provided between the insulator 730 and the EL layer 786. Also, the structure 778 is provided between the insulator 730 and the insulator 734.

[0455] Although not shown in Figure 14, the display device 10 can be equipped with optical components (optical substrates) such as polarizing members, phase difference members, and anti-reflective members.

[0456] Furthermore, a colored layer can be provided. The colored layer is provided so as to have an area that overlaps with the light-emitting element 70. By providing a colored layer, the color purity of the light extracted from the light-emitting element 70 can be increased. As a result, a high-quality image can be displayed on the display device 10. In addition, since, for example, all of the light-emitting elements 70 of the display device 10 can be made into light-emitting elements that emit white light, it is not necessary to form the EL layer 786 by painting different colors, and the display device 10 can be made high-definition.

[0457] <Example of display device configuration 11> Figure 15 is a cross-sectional view showing an example of the configuration of the display device 10. The display device 10 has a substrate 701 and a base material 770, and the substrate 701 and the base material 770 are bonded together by a sealing material 712. The display device 10 shown in Figure 15 differs from the display device 10 shown in Figure 14 in that it has a transistor 601.

[0458] Circuit board 701 A single-crystal semiconductor substrate, such as a single-crystal silicon substrate, can be used as the substrate 701. Alternatively, a semiconductor substrate other than a single-crystal semiconductor substrate may be used as the substrate 701.

[0459] Transistors 441 and 601 are provided on the substrate 701. Transistors 441 and 601 can be transistors provided on layer 20 as shown in Embodiment 6. For example, they can be used as transistors in the drive circuit 40 or the functional circuit 50 of layer 20.

[0460] Transistor 441 The transistor 441 consists of 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 has a semiconductor region 447 including a channel formation region, a low-resistance region 449a that functions as either a source region or a drain region, and a low-resistance region 449b that functions as either a source region or a drain region. The transistor 441 may be either a p-channel or an n-channel type.

[0461] Transistor 441 is electrically isolated from other transistors by the element isolation layer 403. Figure 15 shows the case where transistor 441 and transistor 601 are electrically isolated by the element isolation layer 403. The element isolation layer 403 can be formed using the LOCOS (LOCal Oxidation of Silicon) method or the STI (Shallow Trench Isolation) method, etc.

[0462] In this case, the transistor 441 shown in Figure 15 has a convex semiconductor region 447. Furthermore, the sides and top surface of the semiconductor region 447 are covered by a conductor 443 via an insulator 445. Note that Figure 15 does not show how the conductor 443 covers the sides of the semiconductor region 447. In addition, a material that adjusts the work function can be used for the conductor 443.

[0463] A transistor with a convex semiconductor region, such as transistor 441, can be called a fin-type transistor because it utilizes the convex portion of the semiconductor substrate. It may also have an insulator in contact with the upper part of the convex portion, functioning as a mask for forming the convex portion. Furthermore, while Figure 15 shows a configuration where a portion of the substrate 701 is processed to form the convex portion, a semiconductor with a convex shape may also be formed by processing an SOI substrate.

[0464] Note that the configuration of transistor 441 shown in Figure 15 is just one example, and the system is not limited to this configuration. An appropriate configuration may be used depending on the circuit configuration or the way the circuit operates. For example, transistor 441 may be a planar transistor.

[0465] Transistor 601 Transistor 601 can have the same configuration as transistor 441.

[0466] Insulators 405, 407, 409, and 411 On the substrate 701, in addition to the element isolation layer 403, transistors 441 and 601, insulators 405, 407, 409, and 411 are provided. Conductors 451 are embedded in insulators 405, 407, 409, and 411. Here, the height of the upper surface of the conductor 451 and the height of the upper surface of the insulator 411 can be made to be approximately the same.

[0467] Insulators 405, 407, 409, and 411 may function as interlayer films and as planarizing films that cover the uneven surface beneath them.

[0468] Insulators 421, 214, and 216 Insulators 421 and 214 are provided on the conductor 451 and on the insulator 411, respectively. The conductor 453 is embedded in the insulator 421 and in the insulator 214. Here, the height of the upper surface of the conductor 453 and the height of the upper surface of the insulator 214 can be made to be approximately the same.

[0469] An insulator 216 is provided on the conductor 453 and on the insulator 214. The conductor 455 is embedded in the insulator 216. Here, the height of the upper surface of the conductor 455 and the height of the upper surface of the insulator 216 can be made to be approximately the same.

[0470] Insulators 222, 224, 254, 280, 274, and 281. Insulators 222, 224, 254, 280, 274, and 281 are provided on the conductor 455 and on the insulator 216.

[0471] Conductors 305 are embedded in insulators 222, 224, 254, 280, 274, and 281. Here, the height of the upper surface of the conductor 305 and the height of the upper surface of the insulator 281 can be made to be approximately the same.

[0472] Insulators 421, 214, 280, 274, and 281 may function as interlayer films and as planarizing films that cover the uneven surface beneath them.

[0473] Insulator 361 An insulator 361 is provided on the conductor 305 and on the insulator 281.

[0474] Transistor 441 As shown in Figure 15, the low-resistance region 449b, which functions as either the source region or the drain region of transistor 441, is electrically connected to the FPC 716 via conductors 451, 453, 455, 305, 317, 337, 347, 353, 355, 357, connecting electrode 760, and anisotropic conductor 780.

[0475] <Example of display device configuration 12> Figure 16 is a cross-sectional view showing an example of the configuration of the display device 10. The display device 10 has a substrate 701 and a base material 770, and the substrate 701 and the base material 770 are bonded together by a sealing material 712. The display device 10 shown in Figure 16 differs from the display device 10 shown in Figure 15 in that the transistor 750 has the same configuration as the transistor 441.

[0476] Circuit board 701 A single-crystal semiconductor substrate, such as a single-crystal silicon substrate, can be used as the substrate 701. Alternatively, a semiconductor substrate other than a single-crystal semiconductor substrate may be used as the substrate 701.

[0477] Transistors 441 and 601 are provided on the substrate 701. Transistors 441 and 601 can be transistors provided on layer 20 as shown in Embodiment 6. For example, they can be used as transistors in the drive circuit 40 or the functional circuit 50 of layer 20.

[0478] Transistor 441 The transistor 441 consists of 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 has a semiconductor region 447 including a channel formation region, a low-resistance region 449a that functions as either a source region or a drain region, and a low-resistance region 449b that functions as either a source region or a drain region. The transistor 441 may be either a p-channel or an n-channel type.

[0479] As shown in Figure 16, the low-resistance region 449b, which functions as either the source region or the drain region of transistor 441, is electrically connected to the FPC 716 via conductors 451, 453, 455, bump 458, conductors 305, 317, 337, 347, 353, 355, 357, connecting electrode 760, and anisotropic conductor 780.

[0480] Transistor 441 is electrically isolated from other transistors by the element isolation layer 403. Figure 16 shows the case where transistor 441 and transistor 601 are electrically isolated by the element isolation layer 403. The element isolation layer 403 can be formed using the LOCOS (LOCal Oxidation of Silicon) method or the STI (Shallow Trench Isolation) method, etc.

[0481] In this case, the transistor 441 shown in Figure 16 has a convex semiconductor region 447. Furthermore, the sides and top surface of the semiconductor region 447 are covered by a conductor 443 via an insulator 445. Note that Figure 16 does not show how the conductor 443 covers the sides of the semiconductor region 447. In addition, a material that can be used to adjust the work function can be used for the conductor 443.

[0482] A transistor with a convex semiconductor region, such as transistor 441, can be called a fin-type transistor because it utilizes the convex portion of the semiconductor substrate. It may also have an insulator in contact with the upper part of the convex portion, functioning as a mask for forming the convex portion. Furthermore, while Figure 16 shows a configuration where a portion of the substrate 701 is processed to form the convex portion, a semiconductor with a convex shape may also be formed by processing an SOI substrate.

[0483] Note that the configuration of transistor 441 shown in Figure 16 is just one example, and the system is not limited to this configuration. An appropriate configuration may be used depending on the circuit configuration or the way the circuit operates. For example, transistor 441 may be a planar transistor.

[0484] Transistor 601 Transistor 601 can have the same configuration as transistor 441.

[0485] Insulators 405, 407, 409, and 411 On the substrate 701, in addition to the element isolation layer 403, transistors 441 and 601, insulators 405, 407, 409, and 411 are provided. Conductors 451 are embedded in insulators 405, 407, 409, and 411. Here, the height of the upper surface of the conductor 451 and the height of the upper surface of the insulator 411 can be made to be approximately the same.

[0486] Insulators 405, 407, 409, and 411 may function as interlayer films and as planarizing films that cover the uneven surface beneath them.

[0487] Insulators 421, 214, and 216 Insulators 421 and 214 are provided on the conductor 451 and on the insulator 411, respectively. The conductor 453 is embedded in the insulator 421 and in the insulator 214. Here, the height of the upper surface of the conductor 453 and the height of the upper surface of the insulator 214 can be made to be approximately the same.

[0488] An insulator 216 is provided on the conductor 453 and on the insulator 214. The conductor 455 is embedded in the insulator 216. Here, the height of the upper surface of the conductor 455 and the height of the upper surface of the insulator 216 can be made to be approximately the same.

[0489] 《Adhesive layer 459》 An adhesive layer 459 is provided on the insulator 216. Bumps 458 are embedded in the adhesive layer 459. The adhesive layer 459 adheres the insulator 216 and the substrate 701B. The lower surface of the bump 458 is in contact with the conductor 455, and the upper surface of the bump 458 is in contact with the conductor 305, electrically connecting the conductor 455 and the conductor 305.

[0490] Circuit board 701B A single-crystal semiconductor substrate, such as a single-crystal silicon substrate, can be used as substrate 701B. Alternatively, a semiconductor substrate other than a single-crystal semiconductor substrate may be used as substrate 701B.

[0491] A transistor 750 is provided on the substrate 701B. The transistor 750 can be a transistor provided on layer 30 as shown in Embodiment 6. For example, it can be a transistor provided on pixel circuit 62.

[0492] Transistor 750 Transistor 750 can have the same configuration as transistor 441.

[0493] Insulator 405B, Insulator 280, Insulator 274, Insulator 281 On the substrate 701B, in addition to the element isolation layer 403B and the transistor 750, insulators 405B, 280, 274, and 281 are provided. Conductors 305 are embedded in insulators 405B, 280, 274, and 281. Here, the height of the upper surface of the conductor 305 and the height of the upper surface of the insulator 281 can be made to be approximately the same.

[0494] Insulators 405B, 280, 274, and 281 may function as interlayer films and as planarizing films that cover the uneven surface beneath them.

[0495] Insulator 361 An insulator 361 is provided on the conductor 305 and on the insulator 281.

[0496] <Example of display device configuration 13> The display device 10 shown in Figure 17 differs from the display device 10 shown in Figure 15 mainly in that it has OS transistors, transistors 602 and 603, instead of transistors 441 and 601. Furthermore, an OS transistor can be used for transistor 750. In other words, the display device 10 shown in Figure 17 has OS transistors stacked on top of each other. Note that Figure 17 shows an example where transistors 602 and 603 are mounted on a substrate 701. As mentioned above, the substrate 701 can be a single-crystal semiconductor substrate such as a single-crystal silicon substrate, or other semiconductor substrates. Alternatively, various insulating substrates such as glass substrates or sapphire substrates may be used as the substrate 701.

[0497] Insulators 613 and 614 Insulators 613 and 614 are provided on the substrate 701, and transistors 602 and 603 are provided on the insulator 614. Note that transistors or the like may be provided between the substrate 701 and the insulator 613. For example, a transistor with the same configuration as transistors 441 and 601 shown in Figure 15 may be provided between the substrate 701 and the insulator 613.

[0498] Transistor 602, Transistor 603 Transistors 602 and 603 can be transistors provided in layer 20 as shown in Embodiment 6.

[0499] Transistors 602 and 603 can be transistors with the same configuration as transistor 750. Alternatively, transistors 602 and 603 may be OS transistors with a different configuration than transistor 750.

[0500] Insulators 616, 622, 624, 654, 680, 674, and 681. In addition to transistors 602 and 603, insulators 616, 622, 624, 654, 680, 674, and 681 are provided on insulator 614. Conductors 461 are embedded in insulators 654, 680, 674, and 681. Here, the height of the upper surface of conductor 461 and the height of the upper surface of insulator 681 can be made to be approximately the same.

[0501] Insulator 501 An insulator 501 is provided on the conductor 461 and on the insulator 681. The conductor 463 is embedded in the insulator 501. Here, the height of the upper surface of the conductor 463 and the height of the upper surface of the insulator 501 can be made to be approximately the same.

[0502] Insulators 421 and 214 are provided on the conductor 463 and the insulator 501, respectively. Conductor 453 is embedded in insulator 421 and insulator 214. Here, the height of the upper surface of conductor 453 and the height of the upper surface of insulator 214 can be made to be approximately the same.

[0503] As shown in Figure 17, either the source or drain of transistor 602 is electrically connected to FPC 716 via conductors 461, 463, 453, 455, 305, 317, 337, 347, 353, 355, 357, connecting electrode 760, and anisotropic conductor 780.

[0504] Conductors 305 are embedded in insulators 222, 224, 254, 280, 274, and 281. Here, the height of the upper surface of the conductor 305 and the height of the upper surface of the insulator 281 can be made to be approximately the same.

[0505] Insulators 613, 614, 680, 674, 681, and 501 may function as interlayer films and as planarizing films that cover the uneven shapes beneath them.

[0506] By configuring the display device 10 as shown in Figure 17, the display device 10 can be made smaller and have a narrower bezel, while all of its transistors can be OS transistors. This allows, for example, the transistors provided in layer 20 and layer 30, as shown in Embodiment 6, to be manufactured using the same apparatus. Therefore, the manufacturing cost of the display device 10 can be reduced, making the display device 10 a low-cost product.

[0507] <Example of display device configuration 14> Figure 18 is a cross-sectional view showing an example of the configuration of the display device 10. It differs from the display device 10 shown in Figure 15 in that it has a layer with transistor 800 between the layer with transistor 750 and the layer with transistors 601 and 441.

[0508] In the configuration shown in Figure 18, the layer 20 shown in Embodiment 6 can be composed of a layer having transistors 601 and 441, and a layer having transistor 800. Transistor 750 can be the transistor provided in layer 30 shown in Embodiment 6.

[0509] Insulators 821 and 814 Insulators 821 and 814 are provided on the conductor 451 and the insulator 411, respectively. The conductor 853 is embedded in insulator 821 and insulator 814. Here, the height of the upper surface of the conductor 853 and the height of the upper surface of the insulator 814 can be made to be approximately the same.

[0510] Insulator 816 An insulator 816 is provided on the conductor 853 and on the insulator 814. The conductor 855 is embedded in the insulator 816. Here, the height of the upper surface of the conductor 855 and the height of the upper surface of the insulator 816 can be made to be approximately the same.

[0511] Insulators 822, 824, 854, 880, 874, and 881. Insulators 822, 824, 854, 880, 874, and 881 are provided on the conductor 855 and on the insulator 816. Conductors 805 are embedded in insulators 822, 824, 854, 880, 874, and 881. Here, the height of the upper surface of the conductor 805 and the height of the upper surface of the insulator 881 can be made to be approximately the same.

[0512] Insulators 421 and 214 are provided on the conductor 817 and on the insulator 881, respectively.

[0513] As shown in Figure 18, the low-resistance region 449b, which functions as either the source region or the drain region of transistor 441, is electrically connected to the FPC 716 via conductors 451, 853, 855, 805, 817, 453, 455, 305, 317, 337, 347, 353, 355, 357, connecting electrode 760, and anisotropic conductor 780.

[0514] Transistor 800 A transistor 800 is provided on the insulator 814. The transistor 800 can be the transistor provided on layer 20 as shown in Embodiment 6. It is preferable that the transistor 800 is an OS transistor. For example, the transistor 800 can be the transistor provided in the backup circuit 82.

[0515] Conductors 801a and 801b are embedded in insulators 854, 880, 874, and 881, respectively. Conductor 801a is electrically connected to either the source or drain of transistor 800, and conductor 801b is electrically connected to the other source or drain of transistor 800. Here, the height of the upper surfaces of conductors 801a and 801b can be made to be approximately the same as the height of the upper surface of insulator 881.

[0516] Transistor 750 The transistor 750 can be a transistor provided in layer 30 as shown in Embodiment 6. For example, the transistor 750 can be a transistor provided in pixel circuit 62. It is preferable that the transistor 750 is an OS transistor.

[0517] Insulators 405, 407, 409, 411, 821, 814, 880, 874, 881, 421, 214, 280, 274, 281, 361, and 363 may function as interlayer films and as flattening films that cover the uneven shapes beneath them.

[0518] Figure 18 shows an example in which conductors 801a, 801b, and 805 are formed in the same layer. It also shows an example in which conductors 811, 813, and 817 are formed in the same layer.

[0519] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0520] (Embodiment 8) This embodiment describes a transistor that can be used in a display device according to one aspect of the present invention.

[0521] <Example of transistor configuration> Figures 19A, 19B, and 19C are a top view and a cross-sectional view of transistor 200A and its surroundings, which can be used in a display device according to one aspect of the present invention. Transistor 200A can be applied to a display device according to one aspect of the present invention.

[0522] Figure 19A is a top view of transistor 200A. Figures 19B and 19C are cross-sectional views of transistor 200A. Here, Figure 19B is a cross-sectional view of the area indicated by the dashed line A1-A2 in Figure 19A, and is also a cross-sectional view of transistor 200A in the channel length direction. Similarly, Figure 19C is a cross-sectional view of the area indicated by the dashed line A3-A4 in Figure 19A, and is also a cross-sectional view of transistor 200A in the channel width direction. Note that in the top view of Figure 19A, some elements have been omitted for clarity.

[0523] As shown in Figure 19, the transistor 200A includes a metal oxide 230a disposed on a substrate (not shown), a metal oxide 230b disposed on the metal oxide 230a, conductors 242a and 242b disposed on the metal oxide 230b at a distance from each other, an insulator 280 disposed on the conductors 242a and 242b with an opening formed between the conductors 242a and 242b, a conductor 260 disposed in the opening, an insulator 250 disposed between the metal oxide 230b, conductor 242a, conductor 242b, insulator 280, and conductor 260, and a metal oxide 230c disposed between the metal oxide 230b, conductor 242a, conductor 242b, insulator 280, and insulator 250. Here, as shown in Figures 19B and 19C, it is preferable that the upper surface of the conductor 260 substantially coincides with the upper surfaces of the insulator 250, insulator 254, metal oxide 230c, and insulator 280. In the following, metal oxide 230a, metal oxide 230b, and metal oxide 230c may be collectively referred to as metal oxide 230. Also, conductors 242a and conductors 242b may be collectively referred to as conductor 242.

[0524] In the transistor 200A shown in Figure 19, the sides of conductors 242a and 242b facing conductor 260 have a generally vertical shape. However, the transistor 200A shown in Figure 19 is not limited to this, and the angle between the side and bottom surfaces of conductors 242a and 242b may be 10° to 80°, preferably 30° to 60°. Furthermore, the opposing sides of conductors 242a and 242b may have multiple surfaces.

[0525] As shown in Figure 19, it is preferable that an insulator 254 is placed between the insulator 224, metal oxide 230a, metal oxide 230b, conductor 242a, conductor 242b, and metal oxide 230c and the insulator 280. Here, it is preferable that the insulator 254 is 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 metal oxide 230b, and the top surface of the insulator 224, as shown in Figures 19B and 19C.

[0526] In transistor 200A, a configuration is shown in which three layers of metal oxide 230a, metal oxide 230b, and metal oxide 230c are stacked in the channel formation region (hereinafter also referred to as the channel formation region) and its vicinity. However, the present invention is not limited to this. For example, a two-layer structure of metal oxide 230b and metal oxide 230c, or a stacked structure of four or more layers, may be provided. Also, in transistor 200A, the conductor 260 is shown as a two-layer stacked structure. However, the present invention is not limited to this. For example, the conductor 260 may be a single-layer structure or a stacked structure of three or more layers. Furthermore, each of the metal oxides 230a, 230b, and 230c may have a stacked structure of two or more layers.

[0527] For example, if the 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 the same composition as metal oxide 230b and the second metal oxide has the same composition as metal oxide 230a.

[0528] Here, the conductor 260 functions as the gate electrode of the transistor, and the conductors 242a and 242b function as the source electrode or drain electrode, respectively. As described above, the conductor 260 is formed to be embedded in the opening of the insulator 280 and in the region sandwiched between the conductors 242a and 242b. Here, the arrangement of the conductors 260, 242a, and 242b is selected in a self-aligned manner with respect to the opening of the insulator 280. In other words, in transistor 200A, the gate electrode can be positioned in a self-aligned manner between the source electrode and the drain electrode. Therefore, since the conductor 260 can be formed without providing a positional margin, the occupied area of ​​transistor 200A can be reduced. This makes it possible to make the display device high-resolution. It also makes it possible to make the display device have a narrow bezel.

[0529] As shown in Figure 19, it is preferable that the conductor 260 has a conductor 260a provided inside the insulator 250 and a conductor 260b provided so as to be embedded inside the conductor 260a.

[0530] The transistor 200A preferably includes an insulator 214 disposed on a substrate (not shown), an insulator 216 disposed on top of the insulator 214, a conductor 205 disposed so as to be embedded in the insulator 216, an insulator 222 disposed on top of the insulator 216 and the conductor 205, and an insulator 224 disposed on top of the insulator 222. It is preferable that a metal oxide 230a is disposed on top of the insulator 224.

[0531] It is preferable that insulators 274 and 281, which function as interlayer films, be placed on top of the transistor 200A. Here, it is preferable that insulator 274 is placed in contact with the upper surfaces of the conductor 260, insulator 250, insulator 254, metal oxide 230c, and insulator 280.

[0532] It is preferable that insulators 222, 254, and 274 have a function to suppress the diffusion of hydrogen (for example, at least one such as hydrogen atoms or hydrogen molecules). For example, it is preferable that insulators 222, 254, and 274 have lower hydrogen permeability than insulators 224, 250, and 280. It is also preferable that insulators 222 and 254 have a function to suppress the diffusion of oxygen (for example, at least one such as oxygen atoms or oxygen molecules). For example, it is preferable that insulators 222 and 254 have lower oxygen permeability than insulators 224, 250, and 280.

[0533] Here, insulator 224, metal oxide 230, and insulator 250 are separated from insulators 280 and 281 by insulators 254 and 274. Therefore, it is possible to suppress the mixing of impurities such as hydrogen or excess oxygen contained in insulators 280 and 281 into insulators 224, metal oxide 230a, metal oxide 230b, and insulator 250.

[0534] It is preferable that a conductor 240 (conductor 240a and conductor 240b) is provided that is electrically connected to the transistor 200A and functions as a plug. In addition, an insulator 241 (insulator 241a and insulator 241b) is provided in contact with the side surface of the conductor 240 that functions as a plug. That is, the insulator 241 is provided in contact with the inner wall of the opening of the insulator 254, insulator 280, insulator 274, and insulator 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 upper surface of the conductor 240 and the height of the upper surface of the insulator 281 can be made to be approximately the same. Although the transistor 200A shows a configuration in which the first conductor 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 provided as a single layer or as a laminated structure of three or more layers. When the structure has a laminated structure, an ordinal number may be assigned to distinguish it according to the order of formation.

[0535] In transistor 200A, it is preferable to use a metal oxide that functions as an oxide semiconductor (hereinafter also referred to as an oxide semiconductor) for the metal oxide 230 (metal oxide 230a, metal oxide 230b, and metal oxide 230c) that includes the channel formation region. For example, it is preferable to use a metal oxide with a band gap of 2 eV or more, preferably 2.5 eV or more, as the metal oxide that forms the channel formation region of metal oxide 230.

[0536] The above metal oxide preferably contains at least indium (In) or zinc (Zn). In particular, it is preferable that it contains indium (In) and zinc (Zn). In addition, it is preferable that it contains element M. As element M, one or more of the following can be used: 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 element M is one or more of aluminum (Al), gallium (Ga), yttrium (Y), or tin (Sn). Furthermore, it is even more preferable that element M contains either Ga and Sn or both.

[0537] Furthermore, as shown in Figure 19B, the thickness of the metal oxide 230b in the region that does not overlap with the conductor 242 may be thinner than the thickness of the metal oxide 230b in 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 deposited on the upper surface of the metal oxide 230b, a region with low resistance may be formed near the interface with the conductive film. In this way, by removing the region with low resistance located between the conductors 242a and 242b on the upper surface of the metal oxide 230b, it is possible to prevent the formation of a channel in that region.

[0538] According to one aspect of the present invention, a display device with a small size transistor and high resolution can be provided. Alternatively, a display device with a large on-current transistor and high brightness can be provided. Alternatively, a display device with a fast-operating transistor can be provided. Alternatively, a display device with a stable electrical characteristic transistor can be provided and highly reliable can be provided. Alternatively, a display device with a small off-current transistor can be provided and low power consumption can be provided.

[0539] A detailed configuration of transistor 200A, which can be used in a display device according to one aspect of the present invention, will be described.

[0540] The conductor 205 is arranged so as to have an overlapping region with the metal oxide 230 and the conductor 260. Furthermore, it is preferable that the conductor 205 is embedded in the insulator 216.

[0541] The conductor 205 comprises conductor 205a, conductor 205b, and conductor 205c. Conductor 205a is provided in contact with the bottom surface and side wall of an opening provided in the insulator 216. Conductor 205b is provided so as to be embedded in a recess formed in conductor 205a. Here, the upper surface of conductor 205b is lower than the upper surface of conductor 205a and the upper surface of the insulator 216. Conductor 205c is provided in contact with the upper surface of conductor 205b and the side surface of conductor 205a. Here, the height of the upper surface of conductor 205c is approximately equal to the height of the upper surface of conductor 205a and the upper surface of the insulator 216. In other words, conductor 205b is enclosed by conductors 205a and 205c.

[0542] It is preferable that the conductors 205a and 205c use conductive materials that have the function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (N2O, NO, NO2, etc.), and copper atoms. Alternatively, it is preferable to use conductive materials that have the function of suppressing the diffusion of oxygen (for example, at least one such as oxygen atoms or oxygen molecules).

[0543] By using conductive materials that have the function of reducing hydrogen diffusion for conductors 205a and 205c, it is possible to suppress the diffusion of impurities such as hydrogen contained in conductor 205b into the metal oxide 230 via the insulator 224, etc. Furthermore, by using conductive materials that have the function of suppressing oxygen diffusion for conductors 205a and 205c, it is possible to suppress the oxidation of conductor 205b and the resulting decrease in conductivity. As conductive materials that have the function of suppressing oxygen diffusion, it is preferable to use, for example, titanium, titanium nitride, tantalum, tantalum nitride, ruthenium, ruthenium oxide, etc. Therefore, the conductive material can be used as a single layer or in a laminate for conductor 205a. For example, titanium nitride can be used for conductor 205a.

[0544] Furthermore, it is preferable to use a conductive material whose main component is tungsten, copper, or aluminum for the conductor 205b. For example, tungsten may be used for the conductor 205b.

[0545] Here, conductor 260 may function as the first gate (also called the top gate) electrode. Also, conductor 205 may function as the second gate (also called the bottom gate) electrode. In that case, by changing the potential applied to conductor 205 independently of the potential applied to conductor 260, the V of transistor 200A can be controlled. th This can be controlled. In particular, by applying a negative potential to the conductor 205, the V of transistor 200A can be controlled. th By making the voltage greater than 0V, it becomes possible to reduce the off-current. Therefore, applying a negative potential to the conductor 205 reduces the drain current when the potential applied to the conductor 260 is 0V compared to not applying a negative potential.

[0546] The conductor 205 should be larger than the channel-forming region in the metal oxide 230. In particular, as shown in Figure 19C, it is preferable that the conductor 205 extends to the region outside the end that intersects the channel width direction of the metal oxide 230. That is, it is preferable that the conductor 205 and the conductor 260 are superimposed on the outside of the side surface in the channel width direction of the metal oxide 230, with an insulator in between.

[0547] With the above configuration, the channel-forming region of the metal oxide 230 can be electrically surrounded by the electric field of the conductor 260, which functions as the first gate electrode, and the electric field of the conductor 205, which functions as the second gate electrode.

[0548] As shown in Figure 19C, the conductor 205 is extended to function as wiring. However, the configuration is not limited to this, and a conductor that functions as wiring may be provided beneath the conductor 205.

[0549] The insulator 214 preferably functions as a barrier insulating film that suppresses the ingress of impurities such as water or hydrogen from the substrate side into the transistor 200A. Therefore, it is preferable to use an insulating material for the insulator 214 that has the function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (N2O, NO, NO2, etc.), and copper atoms (i.e., the above impurities are less permeable). Alternatively, it is preferable to use an insulating material that has the function of suppressing the diffusion of oxygen (for example, at least one such as oxygen atoms or oxygen molecules) (i.e., the above oxygen is less permeable).

[0550] For example, it is preferable to use aluminum oxide or silicon nitride as the insulator 214. This suppresses the diffusion of impurities such as water or hydrogen from the substrate side to the transistor 200A side beyond the insulator 214. Alternatively, it suppresses the diffusion of oxygen contained in the insulator 224, etc., to the substrate side beyond the insulator 214.

[0551] The insulators 216, 280, and 281, which function as interlayer films, preferably have a lower dielectric constant than insulator 214. By using a material with a low dielectric constant as the interlayer film, parasitic capacitance between wiring can be reduced. For example, silicon oxide, silicon oxynitride, silicon nitride, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen, or porous silicon oxide may be used as insulators 216, 280, and 281.

[0552] Insulators 222 and 224 function as gate insulators.

[0553] Here, it is preferable that the insulator 224 in contact with the metal oxide 230 deoxygenates upon heating. In this specification, oxygen that is deoxygenated upon heating may be referred to as excess oxygen. For example, the insulator 224 may be silicon oxide or silicon oxide nitride, etc., as appropriate. By providing an oxygen-containing insulator in contact with the metal oxide 230, the oxygen deficiency in the metal oxide 230 can be reduced, and the reliability of the transistor 200A can be improved.

[0554] Specifically, it is preferable to use an oxide material in which some oxygen is desorbed upon heating as the insulator 224. An oxide that desorbs oxygen upon heating is one in which the amount of oxygen desorbed, converted to oxygen atoms, is 1.0 × 10¹⁶ as determined by TDS (Thermal Desorption Spectroscopy) analysis. 18 atoms / cm 3 Preferably 1.0 × 10 19 atoms / cm 3 More preferably 2.0 × 10 19 atoms / cm 3 Above, or 3.0 × 10 20 atoms / cm 3 The oxide film is as described above. The surface temperature of the film during the TDS analysis is preferably in the range of 100°C to 700°C, or 100°C to 400°C.

[0555] As shown in Figure 19C, the thickness of the insulator 224 in the region that does not overlap with the insulator 254 and does not overlap with the metal oxide 230b may be thinner than the thickness of the other regions. In the insulator 224, it is preferable that the thickness of the region that does not overlap with the insulator 254 and does not overlap with the metal oxide 230b is such that the above-mentioned oxygen can diffuse sufficiently.

[0556] The insulator 222 preferably functions as a barrier insulating film that suppresses the ingress of impurities such as water or hydrogen into the transistor 200A from the substrate side, similar to the insulator 214. For example, it is preferable that the insulator 222 has lower hydrogen permeability than the insulator 224. By surrounding the insulator 224, metal oxide 230, and insulator 250, etc., with the insulators 222, 254, and 274, it is possible to suppress the ingress of impurities such as water or hydrogen into the transistor 200A from the outside.

[0557] Furthermore, it is preferable that the insulator 222 has a function to suppress the diffusion of oxygen (for example, at least one such as an oxygen atom or oxygen molecule) (i.e., it is difficult for the above-mentioned oxygen to permeate it). For example, it is preferable that the insulator 222 has lower oxygen permeability than the insulator 224. It is preferable that the insulator 222 has a function to suppress the diffusion of oxygen or impurities, thereby reducing the diffusion of oxygen contained in the metal oxide 230 to the substrate side. In addition, it is possible to suppress the reaction of the conductor 205 with the oxygen contained in the insulator 224 or the metal oxide 230.

[0558] The insulator 222 may be an insulator containing an oxide of either or both aluminum and hafnium, which are insulating materials. Preferably, the insulator containing an oxide of either or both aluminum and hafnium is an aluminum oxide, hafnium oxide, or an 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 the release of oxygen from the metal oxide 230 or the incorporation of impurities such as hydrogen from the periphery of the transistor 200A into the metal oxide 230.

[0559] Alternatively, 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 subjected to nitriding treatment. Silicon oxide, silicon oxynitride, or silicon nitride may be laminated onto the above insulators.

[0560] The insulator 222 may be a single-layer or multi-layer insulator containing so-called high-k materials such as aluminum oxide, hafnium oxide, tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO3), or (Ba,Sr)TiO3 (BST). As transistors become smaller and more integrated, thinning of the gate insulator can lead to problems such as leakage current. 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.

[0561] Furthermore, the insulators 222 and 224 may have a laminated structure of two or more layers. In that case, the laminated structure is not limited to being made of the same material, but may be made of different materials. For example, an insulator similar to the insulator 224 may be provided below the insulator 222.

[0562] The metal oxide 230 comprises a metal oxide 230a, a metal oxide 230b on the metal oxide 230a, and a metal oxide 230c on the metal oxide 230b. By having the metal oxide 230a below the metal oxide 230b, the diffusion of impurities from structures formed below the metal oxide 230a to the metal oxide 230b can be suppressed. Furthermore, by having the metal oxide 230c on the metal oxide 230b, the diffusion of impurities from structures formed above the metal oxide 230c to the metal oxide 230b can be suppressed.

[0563] Furthermore, it is preferable that the metal oxide 230 has a layered structure of multiple oxide layers with different atomic ratios of each metal atom. For example, if the metal oxide 230 contains at least indium (In) and element M, it is preferable that the ratio of the number of atoms of element M contained in metal oxide 230a to the total number of atoms of all elements constituting metal oxide 230a is higher than the ratio of the number of atoms of element M contained in metal oxide 230b to the total number of atoms of all elements constituting metal oxide 230b. It is also preferable that the atomic ratio of element M contained in metal oxide 230a to In is higher than the atomic ratio of element M contained in metal oxide 230b to In. Here, metal oxide 230c can be any metal oxide that can be used in metal oxide 230a or metal oxide 230b.

[0564] It is preferable that the energy at the lower end of the conduction band of metal oxide 230a and metal oxide 230c is higher than the energy at the lower end of the conduction band of metal oxide 230b. In other words, it is preferable that the electron affinity of metal oxide 230a and metal oxide 230c is smaller than the electron affinity of metal oxide 230b. In this case, it is preferable that metal oxide 230c is a metal oxide that can be used for metal oxide 230a. Specifically, it is preferable that the ratio of the number of atoms of element M contained in metal oxide 230c to the total number of atoms of all elements constituting metal oxide 230c is higher than the ratio of the number of atoms of element M contained in metal oxide 230b to the total number of atoms of all elements constituting metal oxide 230b. It is also preferable that the atomic ratio of element M contained in metal oxide 230c to In is higher than the atomic ratio of element M contained in metal oxide 230b to In.

[0565] Here, at the junctions of metal oxide 230a, metal oxide 230b, and metal oxide 230c, the energy level at the lower end of the conduction band changes smoothly. In other words, the energy level at the lower end of the conduction band at the junctions of metal oxide 230a, metal oxide 230b, and metal oxide 230c can be said to change continuously or be continuously joined. To achieve this, it is desirable to lower the defect level density of the mixed layer formed at the interface between metal oxide 230a and metal oxide 230b, and at the interface between metal oxide 230b and metal oxide 230c.

[0566] Specifically, a mixed layer with a low defect level density can be formed by having metal oxide 230a and metal oxide 230b, and metal oxide 230b and metal oxide 230c, all having a common element other than oxygen (which serves as the main component). For example, if metal oxide 230b is In-Ga-Zn oxide, then In-Ga-Zn oxide, Ga-Zn oxide, gallium oxide, etc., may be used as metal oxide 230a and metal oxide 230c. Furthermore, metal oxide 230c may be in a layered structure. For example, a layered structure of In-Ga-Zn oxide and Ga-Zn oxide on the In-Ga-Zn oxide, or a layered structure of In-Ga-Zn oxide and gallium oxide on the In-Ga-Zn oxide can be used. In other words, a layered structure of In-Ga-Zn oxide and an oxide that does not contain In may be used as metal oxide 230c.

[0567] Specifically, for metal oxide 230a, a metal oxide with an atomic ratio of In:Ga:Zn = 1:3:4 or 1:1:0.5 may be used. For metal oxide 230b, a metal oxide with an atomic ratio of In:Ga:Zn = 4:2:3 or 3:1:2 may be used. For metal oxide 230c, a metal oxide with 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 may be used. Furthermore, specific examples of layered structures for metal oxide 230c include a layered structure of In:Ga:Zn=4:2:3 [atomic ratio] and Ga:Zn=2:1 [atomic ratio], a layered structure of In:Ga:Zn=4:2:3 [atomic ratio] and Ga:Zn=2:5 [atomic ratio], and a layered structure of In:Ga:Zn=4:2:3 [atomic ratio] and gallium oxide.

[0568] In this case, the main carrier pathway is metal oxide 230b. By configuring metal oxide 230a and metal oxide 230c as described above, the defect level density at the interface between metal oxide 230a and metal oxide 230b, and at the interface between metal oxide 230b and metal oxide 230c, can be reduced. As a result, the influence of interface scattering on carrier conduction is reduced, and transistor 200A can obtain high on-current and high frequency characteristics. Furthermore, if metal oxide 230c is in a multilayer structure, in addition to the effect of reducing the defect level density at the interface between metal oxide 230b and metal oxide 230c as described above, it is expected that the diffusion of constituent elements of metal oxide 230c to the insulator 250 side will be suppressed. More specifically, by making metal oxide 230c in a multilayer structure and positioning an oxide that does not contain In on top of the multilayer structure, it is possible to suppress In that could diffuse to the insulator 250 side. Since insulator 250 functions as a gate insulator, if In diffuses, it will result in poor transistor characteristics. Therefore, by using a layered structure for the metal oxide 230c, it becomes possible to provide a highly reliable display device.

[0569] A conductor 242 (conductor 242a and conductor 242b) that functions as a source electrode and a drain electrode is provided on the metal oxide 230b. 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, and lanthanum as the conductor 242, or an alloy containing the above metal elements, 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.

[0570] By providing the conductor 242 in contact with the metal oxide 230, the oxygen concentration in the vicinity of the conductor 242 in the metal oxide 230 may be reduced. In addition, a metal compound layer containing the metal in the conductor 242 and the components of the metal oxide 230 may be formed in the vicinity of the conductor 242 in the metal oxide 230. In such a case, the carrier density increases in the region of the metal oxide 230 near the conductor 242, and this region becomes a low-resistance region.

[0571] Here, the region between the conductor 242a and the conductor 242b is formed by superimposing it on the opening of the insulator 280. This allows the conductor 260 to be positioned self-aligned between the conductor 242a and the conductor 242b.

[0572] The insulator 250 functions as a gate insulator. It is preferable that the insulator 250 be placed in contact with the upper surface of the metal oxide 230c. The insulator 250 can be silicon oxide, silicon oxide nitride, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen, or silicon oxide with vacancies. In particular, silicon oxide and silicon oxide nitride are preferred because they are stable with respect to heat.

[0573] Similar to the insulator 224, it is preferable that the concentration of impurities such as water or hydrogen in the insulator 250 is reduced. The film thickness of the insulator 250 is preferably 1 nm or more and 20 nm or less.

[0574] A metal oxide may be provided between the insulator 250 and the conductor 260. It is preferable that the metal oxide suppresses oxygen diffusion from the insulator 250 to the conductor 260. This suppresses the oxidation of the conductor 260 by oxygen from the insulator 250.

[0575] 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 making the gate insulator a laminated structure of insulator 250 and the metal oxide, a laminated structure that is stable against heat and has a high dielectric constant can be made. Therefore, it becomes possible to reduce the gate potential applied during transistor operation while maintaining the physical film thickness of the gate insulator. In addition, it becomes possible to thin the equivalent oxide film thickness (EOT) of the insulator that functions as a gate insulator.

[0576] Specifically, metal oxides containing one or more selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, or magnesium can be used. In particular, it is preferable to use insulators containing oxides of aluminum, hafnium, or both, such as aluminum oxide, hafnium oxide, or an oxide containing aluminum and hafnium (hafnium aluminate).

[0577] Although the conductor 260 is shown as a two-layer structure in Figure 19, it may also be a single-layer structure or a laminated structure of three or more layers.

[0578] It is preferable to use a conductor 260a that has the function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (N2O, NO, NO2, etc.), and copper atoms. Alternatively, it is preferable to use a conductive material that has the function of suppressing the diffusion of oxygen (for example, at least one such as oxygen atoms or oxygen molecules).

[0579] The conductor 260a has the function of suppressing oxygen diffusion, thereby preventing the conductor 260b from oxidizing due to oxygen contained in the insulator 250 and reducing its conductivity. It is preferable to use, for example, tantalum, tantalum nitride, ruthenium, or ruthenium oxide as a conductive material that has the function of suppressing oxygen diffusion.

[0580] The conductor 260b is preferably made of a conductive material mainly composed of tungsten, copper, or aluminum. Furthermore, since the conductor 260 also functions as wiring, it is preferable to use a conductor with high conductivity. For example, a conductive material mainly composed of tungsten, copper, or aluminum can be used. The conductor 260b may also have a laminated structure, for example, a laminated structure of titanium or titanium nitride and the above conductive material.

[0581] As shown in Figures 19A and 19C, in the region of the metal oxide 230b that does not overlap with the conductor 242, in other words, in the channel-forming region of the metal oxide 230, the side surface of the metal oxide 230 is covered by the conductor 260. This makes it easier to apply the electric field of the conductor 260, which functions as the first gate electrode, to the side surface of the metal oxide 230. Therefore, the on-current of transistor 200A can be increased and the frequency characteristics can be improved.

[0582] The insulator 254, like the insulator 214, preferably functions as a barrier insulating film that suppresses the ingress of impurities such as water or hydrogen into the transistor 200A from the insulator 280 side. For example, it is preferable that the insulator 254 has lower hydrogen permeability than the insulator 224. Furthermore, as shown in Figures 19B and 19C, it is preferable that the insulator 254 is 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 metal oxide 230b, and the top surface of the insulator 224. With this configuration, it is possible to suppress the ingress of hydrogen contained in the insulator 280 into the metal oxide 230 from the top or side surfaces of the conductor 242a, conductor 242b, metal oxide 230a, metal oxide 230b, and the insulator 224.

[0583] Furthermore, it is preferable that the insulator 254 has the function of suppressing the diffusion of oxygen (for example, at least one such as an oxygen atom or oxygen molecule) (i.e., it is difficult for the above-mentioned oxygen to permeate through it). For example, it is preferable that the insulator 254 has lower oxygen permeability than the insulator 280 or the insulator 224.

[0584] The insulator 254 is preferably deposited using a sputtering method. By depositing the insulator 254 using a sputtering method in an oxygen-containing atmosphere, oxygen can be added to the vicinity of the region of the insulator 224 that is in contact with the insulator 254. This allows oxygen to be supplied from this region to the metal oxide 230 via the insulator 224. Here, the insulator 254 has a function to suppress upward diffusion of oxygen, thereby preventing oxygen from diffusing from the metal oxide 230 to the insulator 280. In addition, the insulator 222 has a function to suppress downward diffusion of oxygen, thereby preventing oxygen from diffusing from the metal oxide 230 to the substrate side. In this way, oxygen is supplied to the channel formation region of the metal oxide 230. This reduces oxygen deficiency in the metal oxide 230 and suppresses normally-on formation of the transistor.

[0585] As the insulator 254, for example, an insulator containing an oxide of one or both of aluminum and hafnium may be formed as a film. It is preferable to use aluminum oxide, hafnium oxide, or an oxide containing aluminum and hafnium (hafnium aluminate) as the insulator containing an oxide of one or both of aluminum and hafnium.

[0586] The insulator 224, insulator 250, and metal oxide 230 are covered by the hydrogen barrier insulator 254, so the insulator 280 is separated from the insulator 224, metal oxide 230, and insulator 250 by the insulator 254. This prevents impurities such as hydrogen from entering the transistor 200A from the outside, thus providing the transistor 200A with good electrical characteristics and reliability.

[0587] The insulator 280 is provided on the insulator 224, the metal oxide 230, and the conductor 242 via the insulator 254. For example, the insulator 280 is preferably silicon oxide, silicon oxynitride, silicon nitride, fluorine-added silicon oxide, carbon-added silicon oxide, carbon and nitrogen-added silicon oxide, or porous silicon oxide. Silicon oxide and silicon oxynitride are particularly preferred because they are thermally stable. Materials such as silicon oxide, silicon oxynitride, and porous silicon oxide are particularly preferred because they can easily form regions containing oxygen that is desorbed by heating.

[0588] It is preferable that the concentration of impurities such as water or hydrogen in the insulator 280 is reduced. Furthermore, the upper surface of the insulator 280 may be flattened.

[0589] The insulator 274 preferably functions as a barrier insulating film that suppresses the incorporation of impurities such as water or hydrogen into the insulator 280 from above, similar to the insulator 214. For example, the insulator 274 can be an insulator that can be used for the insulator 214, insulator 254, etc.

[0590] It is preferable to provide an insulator 281, which functions as an interlayer film, on top of the insulator 274. It is preferable that the insulator 281, like the insulator 224, has a reduced concentration of impurities such as water or hydrogen in the film.

[0591] Conductors 240a and 240b are placed in the openings formed in insulators 281, 274, 280, and 254. Conductors 240a and 240b are provided facing each other with conductor 260 in between. The height of the upper surfaces of conductors 240a and 240b may be on the same plane as the upper surface of insulator 281.

[0592] Furthermore, an insulator 241a is provided in contact with the inner wall of the opening of insulators 281, 274, 280, and 254, and a first conductive portion of conductor 240a is formed in contact with its side surface. Conductor 242a is located in at least a portion of the bottom of the opening, and conductor 240a is in contact with conductor 242a. Similarly, an insulator 241b is provided in contact with the inner wall of the opening of insulators 281, 274, 280, and 254, and a first conductive portion of conductor 240b is formed in contact with its side surface. Conductor 242b is located in at least a portion of the bottom of the opening, and conductor 240b is in contact with conductor 242b.

[0593] It is preferable that the conductors 240a and 240b are made of conductive materials mainly composed of tungsten, copper, or aluminum. Furthermore, the conductors 240a and 240b may be arranged in a laminated structure.

[0594] When the conductor 240 has a laminated structure, it is preferable to use a conductor that has the function of suppressing the diffusion of impurities such as water or hydrogen, as described above, for the conductors that come into contact with the metal oxide 230a, metal oxide 230b, conductor 242, insulator 254, insulator 280, insulator 274, and 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 laminate. By using such a conductive material, it is possible to suppress the absorption of oxygen added to the insulator 280 by the conductors 240a and 240b. In addition, it is possible to suppress the mixing of impurities such as water or hydrogen from the layer above the insulator 281 into the metal oxide 230 through the conductors 240a and 240b.

[0595] For insulators 241a and 241b, any insulator that can be used for insulator 254, for example, may be used. Since insulators 241a and 241b are provided in contact with insulator 254, it is possible to suppress the mixing of impurities such as water or hydrogen from insulator 280, etc., into the metal oxide 230 through conductors 240a and 240b. Furthermore, it is possible to suppress the absorption of oxygen contained in insulator 280 into conductors 240a and 240b.

[0596] Although not shown in the figures, conductors that function as wiring may be placed in contact with the upper surfaces of conductor 240a and conductor 240b. It is preferable that the conductors functioning as wiring be made of a conductive material mainly composed of tungsten, copper, or aluminum. Furthermore, the conductors may have a laminated structure; for example, they may be laminates of titanium or titanium nitride with the conductive material. The conductors may also be formed to be embedded in openings provided in the insulator.

[0597] <Materials used in transistors> This section describes the constituent materials that can be used in transistors.

[0598] [substrate] As the substrate for forming transistor 200A, for example, an insulating substrate, a semiconductor substrate, or a conductive substrate may be used. Examples of insulating substrates include glass substrates, quartz substrates, sapphire substrates, stabilized zirconia substrates (such as yttria-stabilized zirconia substrates), and resin substrates. Examples of semiconductor substrates include silicon, germanium, and other semiconductor substrates, or compound semiconductor substrates made of silicon carbide, silicon germanium, gallium arsenide, indium phosphide, zinc oxide, and gallium oxide. Furthermore, there are semiconductor substrates having insulating regions within the aforementioned semiconductor substrates, such as SOI (Silicon On Insulator) substrates. Examples of conductive substrates include graphite substrates, metal substrates, alloy substrates, and conductive resin substrates. Alternatively, there are substrates having metal nitrides, substrates having metal oxides, etc. Furthermore, there are substrates on which a conductor or semiconductor is provided on an insulating substrate, substrates on which a conductor or insulator is provided on a semiconductor substrate, and substrates on which a semiconductor or insulator is provided on a conductive substrate. Alternatively, substrates on which elements are provided may be used. Elements provided on a substrate include capacitive elements, resistive elements, switch elements, light-emitting elements, and memory elements.

[0599] [Insulator] Insulators include insulating oxides, nitrides, oxidized nitrides, nitride oxides, metal oxides, metal oxidized nitrides, and metal nitride oxides.

[0600] For example, as transistors become smaller and more integrated, thinning of the gate insulator can lead to problems such as leakage current. By using a high-k material for the insulator that functions as the gate insulator, it is possible to lower the voltage during transistor operation while maintaining the physical film thickness. On the other hand, by using a material with a low dielectric constant for the insulator that functions as the interlayer film, parasitic capacitance between wiring can be reduced. Therefore, it is best to select the material according to the function of the insulator.

[0601] Examples of insulators with high dielectric constants include gallium oxide, hafnium oxide, zirconium oxide, oxides containing aluminum and hafnium, oxide nitrides containing aluminum and hafnium, oxides containing silicon and hafnium, oxide nitrides containing silicon and hafnium, or nitrides containing silicon and hafnium.

[0602] Examples of insulators with low dielectric constant include silicon oxide, silicon oxide nitride, silicon oxide nitride, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen, silicon oxide with voids, or resins.

[0603] Transistors using oxide semiconductors can have their electrical characteristics stabilized by surrounding them with an insulator (insulator 214, insulator 222, insulator 254, and insulator 274, etc.) that has the function of suppressing the permeation of impurities such as hydrogen and oxygen. As an insulator that has the function of suppressing the permeation of impurities such as hydrogen and oxygen, for example, an insulator containing boron, carbon, nitrogen, oxygen, fluorine, magnesium, aluminum, silicon, phosphorus, chlorine, argon, gallium, germanium, yttrium, zirconium, lanthanum, neodymium, hafnium, or tantalum may be used in a single layer or in a multilayer structure. Specifically, as an insulator that has the function of suppressing the permeation of impurities such as hydrogen and oxygen, metal oxides such as aluminum oxide, magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, or tantalum oxide, metal nitrides such as aluminum nitride, titanium aluminum nitride, titanium nitride, silicon oxide nitride, or silicon nitride can be used.

[0604] The insulator that functions as a gate insulator is preferably an insulator having a region containing oxygen that is released by heating. For example, by having 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, the oxygen deficiency of the metal oxide 230 can be compensated for.

[0605] [conductor] It is preferable to use a metallic 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., as a conductor, or an alloy containing the above metallic elements, or an alloy combining the above metallic 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. Alternatively, semiconductors with high electrical conductivity, such as polycrystalline silicon containing impurity elements like phosphorus, or silicides such as nickel silicide may be used.

[0606] Multiple conductors formed from the above materials may be used in a laminated structure. For example, a laminated structure may be formed by combining a material containing the aforementioned metal element with a conductive material containing oxygen. Alternatively, a laminated structure may be formed by combining a material containing the aforementioned metal element with a conductive material containing nitrogen. Furthermore, a laminated structure may be formed by combining a material containing the aforementioned metal element with a conductive material containing oxygen and a conductive material containing nitrogen.

[0607] Furthermore, when using a metal oxide for the channel formation region of a transistor, it is preferable to use a laminated structure for the conductor functioning as the gate electrode, which combines a material containing the aforementioned metal element with a conductive material containing oxygen. In this case, it is preferable to place the conductive material containing oxygen on the channel formation region side. By placing the conductive material containing oxygen on the channel formation region side, oxygen released from the conductive material is more easily supplied to the channel formation region.

[0608] In particular, it is preferable to use a conductive material containing metal elements and oxygen contained in the metal oxide in which the channel is formed as the conductor that functions as the gate electrode. Alternatively, conductive materials containing the aforementioned metal elements and nitrogen may be used. For example, conductive materials containing nitrogen such as titanium nitride and tantalum nitride may be used. In addition, 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, and silicon-added indium tin oxide may be used. In addition, indium gallium zinc oxide containing nitrogen may be used. By using such materials, it may be possible to capture hydrogen contained in the metal oxide in which the channel is formed. Alternatively, it may be possible to capture hydrogen that is mixed in from an external insulator or the like.

[0609] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0610] (Embodiment 9) This embodiment describes metal oxides (hereinafter also referred to as oxide semiconductors) that can be used in the OS transistor described in the above embodiment.

[0611] <Classification of crystal structures> First, we will explain the classification of crystal structures in oxide semiconductors using Figure 20A. Figure 20A is a diagram illustrating the classification of crystal structures in oxide semiconductors, specifically IGZO (a metal oxide containing In, Ga, and Zn).

[0612] As shown in Figure 20A, oxide semiconductors are broadly classified into "Amorphous," "Crystalline," and "Crystal." "Amorphous" includes completely amorphous materials. "Crystalline" includes CAAC (c-axis-aligned crystalline), nc (nanocrystalline), and CAC (cloud-aligned composite) (excluding single crystal and polycrystal). Note that single crystal, polycrystal, and completely amorphous materials are excluded from the "Crystalline" classification. "Crystal" includes single crystal and polycrystal materials.

[0613] The structure within the thick frame shown in Figure 20A represents an intermediate state between "Amorphous" and "Crystal," and belongs to a new boundary region (New crystalline phase). In other words, this structure can be described as being completely different from the energetically unstable "Amorphous" and "Crystal" states.

[0614] The crystal structure of a film or substrate can be evaluated using X-ray diffraction (XRD) spectroscopy. Figure 20B shows the XRD spectrum obtained by GIXD (Grazing-Incidence XRD) measurement of a CAAC-IGZO film classified as "Crystalline." The GIXD method is also known as the thin-film method or Seemann-Bohlin method. Hereafter, the XRD spectrum obtained by the GIXD measurement shown in Figure 20B will simply be referred to as the XRD spectrum. The composition of the CAAC-IGZO film shown in Figure 20B is approximately In:Ga:Zn = 4:2:3 [atomic ratio]. The thickness of the CAAC-IGZO film shown in Figure 20B is 500 nm.

[0615] As shown in Figure 20B, the XRD spectrum of the CAAC-IGZO film shows a peak indicating clear crystallinity. Specifically, the XRD spectrum of the CAAC-IGZO film shows a peak indicating c-axis orientation near 2θ=31°. As shown in Figure 20B, the peak near 2θ=31° is asymmetrical with respect to the angle at which the peak intensity was detected.

[0616] The crystal structure of a film or substrate can be evaluated by the diffraction pattern (also called the nano-beam electron diffraction pattern) observed by nano-beam electron diffraction (NBED). The diffraction pattern of a CAAC-IGZO film is shown in Figure 20C. Figure 20C shows the diffraction pattern observed by NBED with the electron beam incident parallel to the substrate. The composition of the CAAC-IGZO film shown in Figure 20C is approximately In:Ga:Zn = 4:2:3 [atomic ratio]. Furthermore, in nano-beam electron diffraction, electron diffraction is performed with a probe diameter of 1 nm.

[0617] As shown in Figure 20C, the diffraction pattern of the CAAC-IGZO film shows multiple spots indicating c-axis orientation.

[0618] [Structure of oxide semiconductors] Note that when focusing on the crystal structure, oxide semiconductors may be classified differently from those shown in Figure 20A. For example, oxide semiconductors can be divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the aforementioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors also include polycrystalline oxide semiconductors, pseudo-amorphous oxide semiconductors (a-like OS), amorphous oxide semiconductors, etc.

[0619] Here, we will explain the details of the CAAC-OS, nc-OS, and a-like OS mentioned above.

[0620] [CAAC-OS] CAAC-OS is an oxide semiconductor having multiple crystalline regions, the c-axis of which is oriented in a specific direction. This specific direction is the thickness direction of the CAAC-OS film, the normal direction to the surface on which the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region with periodic atomic arrangement. If we consider the atomic arrangement as a lattice arrangement, then a crystalline region is also a region with a aligned lattice arrangement. Furthermore, CAAC-OS has regions where multiple crystalline regions are connected in the ab-plane direction, and these regions may exhibit distortion. Distortion refers to a point in the connected region where the orientation of the lattice arrangement changes between a region with a aligned lattice arrangement and another region with a aligned lattice arrangement. In short, CAAC-OS is an oxide semiconductor that is c-axis oriented and does not exhibit clear orientation in the ab-plane direction.

[0621] Each of the multiple crystalline regions described above 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 that crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of that crystalline region may be around several tens of nanometers.

[0622] In In-M-Zn oxide (where element M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, etc.), CAAC-OS tends to have a layered crystalline structure (also called a layered structure) consisting of layers containing indium (In) and oxygen (hereinafter referred to as the In layer) and layers containing element M, zinc (Zn), and oxygen (hereinafter referred to as the (M,Zn) layer). Indium and element M are mutually substitutable. Therefore, the (M,Zn) layer may contain indium. The In layer may also contain element M. The In layer may also contain Zn. This layered structure can be observed, for example, as a lattice image in high-resolution TEM images.

[0623] When structural analysis of a CAAC-OS film is performed using an XRD instrument, for example, out-of-plane XRD measurements using θ / 2θ scanning show a peak indicating c-axis orientation at 2θ = 31° or nearby. Note that the position of the peak indicating c-axis orientation (value of 2θ) may vary depending on the type and composition of the metal elements constituting the CAAC-OS.

[0624] For example, multiple bright spots are observed in the electron diffraction pattern of a CAAC-OS film. These spots are observed at point-symmetric positions with respect to the incident electron beam spot (also called the direct spot) that passed through the sample.

[0625] When the crystal region is observed from the specific direction described above, the lattice arrangement within that crystal region is based on a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be non-regular hexagonal. Furthermore, the strain may have lattice arrangements such as pentagons or heptagons. Moreover, in CAAC-OS, clear grain boundaries cannot be observed even near the strain. In other words, it can be seen that the formation of grain boundaries is suppressed by the strain in the lattice arrangement. This is thought to be because CAAC-OS can tolerate strain due to the non-dense arrangement of oxygen atoms in the ab-plane direction, or because the bond distance between atoms changes due to the substitution of metal atoms.

[0626] A crystal structure in which clear grain boundaries are observed is called a polycrystal. Grain boundaries act as recombination centers, trapping carriers and potentially causing a decrease in transistor on-current and field-effect mobility. Therefore, CAAC-OS, in which clear grain boundaries are not observed, is one of the crystalline oxides with a suitable crystal structure for the semiconductor layer of a transistor. In addition, a structure containing Zn is preferred for the composition of CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are preferred because they suppress the generation of grain boundaries more effectively than In oxide.

[0627] CAAC-OS is an oxide semiconductor with high crystallinity and no clearly defined grain boundaries. Therefore, CAAC-OS is less susceptible to the decrease in electron mobility caused by grain boundaries. Furthermore, since the crystallinity of oxide semiconductors can decrease due to the inclusion of impurities or the generation of defects, CAAC-OS can be said to be an oxide semiconductor with few impurities or defects (such as oxygen vacancies). Consequently, oxide semiconductors containing CAAC-OS have stable physical properties. Therefore, oxide semiconductors containing CAAC-OS are heat-resistant and highly reliable. In addition, CAAC-OS is stable even at high temperatures (so-called thermal budget) during the manufacturing process. Therefore, using CAAC-OS in OS transistors allows for greater flexibility in the manufacturing process.

[0628] [nc-OS] nc-OS exhibits periodicity in atomic arrangement in minute regions (e.g., regions between 1 nm and 10 nm, particularly between 1 nm and 3 nm). In other words, nc-OS contains minute crystals. These minute crystals are also called nanocrystals because their size is, for example, between 1 nm and 10 nm, particularly between 1 nm and 3 nm. Furthermore, nc-OS shows no regularity in crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Consequently, depending on the analytical method, nc-OS may be indistinguishable from a-like OS or amorphous oxide semiconductors. For example, when structural analysis of an nc-OS film is performed using an XRD instrument, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Also, when electron diffraction (also called limited-field electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter larger than that of the nanocrystals (e.g., 50 nm or larger), a diffraction pattern resembling a halo pattern is observed. On the other hand, when electron diffraction (also called nanobeam electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter close to or smaller than the size of the nanocrystal (for example, 1 nm to 30 nm), an electron diffraction pattern may be obtained in which multiple spots are observed within a ring-shaped region centered on a direct spot.

[0629] [a-like OS] a-like OS is an oxide semiconductor having a structure between nc-OS and amorphous oxide semiconductors. a-like OS has porous or low-density regions. That is, a-like OS has lower crystallinity compared to nc-OS and CAAC-OS. Also, a-like OS has a higher hydrogen concentration in the film compared to nc-OS and CAAC-OS.

[0630] [Oxide semiconductor configuration] Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS refers to the material composition.

[0631] [CAC-OS] CAC-OS is a material composition in which, for example, the elements constituting the metal oxide are unevenly distributed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size. In the following, a state in which one or more metal elements are unevenly distributed in a metal oxide, and the regions containing these metal elements are mixed in sizes of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or close to that size, is also referred to as a mosaic or patchy state.

[0632] Furthermore, CAC-OS is a composite metal oxide having a mosaic-like structure formed by the separation of the material into a first region and a second region, with the first region distributed within the film (hereinafter also referred to as a cloud-like structure). In other words, CAC-OS is a composite metal oxide having a structure in which the first region and the second region are mixed.

[0633] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in In-Ga-Zn oxide are denoted as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS of In-Ga-Zn oxide, the first region is the region where [In] is greater than the [In] in the composition of the CAC-OS film. The second region is the region where [Ga] is greater than the [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is the region where [In] is greater than the [In] in the second region, and [Ga] is smaller than the [Ga] in the second region. The second region is the region where [Ga] is greater than the [Ga] in the first region, and [In] is smaller than the [In] in the first region.

[0634] Specifically, the first region described above is a region whose main components are indium oxide, indium zinc oxide, etc. The second region described above is a region whose main components are gallium oxide, gallium zinc oxide, etc. In other words, the first region can be rephrased as a region whose main component is In. Similarly, the second region can be rephrased as a region whose main component is Ga.

[0635] Furthermore, a clear boundary may not be observed between the first region and the second region described above.

[0636] For example, in the case of CAC-OS in In-Ga-Zn oxide, EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX) confirms that it has a structure in which regions mainly composed of In (first region) and regions mainly composed of Ga (second region) are unevenly distributed and mixed.

[0637] When CAC-OS is used in a transistor, the conductivity due to the first region and the insulation due to the second region work complementaryly to give CAC-OS a switching function (on / off function). In other words, CAC-OS has conductive function in part of the material, insulating function in part of the material, and semiconductor function as a whole. By separating the conductive function and the insulating function, both functions can be maximized. Therefore, by using CAC-OS in a transistor, a high on-current (I) can be achieved. on ), high field-effect mobility (μ), and good switching operation can be achieved.

[0638] Oxide semiconductors can take on diverse structures, each possessing different properties. One embodiment of the present invention may include two or more of the following: amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, CAC-OS, nc-OS, and CAAC-OS.

[0639] <Transistors containing oxide semiconductors> Next, we will explain the case where the above oxide semiconductor is used in a transistor.

[0640] By using the above-mentioned oxide semiconductor in transistors, it is possible to realize transistors with high field-effect mobility. Furthermore, it is possible to realize highly reliable transistors.

[0641] It is preferable to use an oxide semiconductor with a low carrier concentration for the transistor. For example, the carrier concentration of an oxide semiconductor is 1 × 10⁻⁶. 17 cm -3 The following is preferably 1 × 10 15 cm -3 More preferably 1 × 10 13 cm -3 More preferably 1 × 10 11 cm -3 More preferably 1 × 10 10 cm -3 It is less than 1 × 10 -9 cm -3 This concludes the explanation. Furthermore, when lowering the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film should be lowered to reduce the defect level density. In this specification, a low impurity concentration and low defect level density are referred to as high-purity intrinsic or substantially high-purity intrinsic. Note that oxide semiconductors with low carrier concentrations are sometimes referred to as high-purity intrinsic or substantially high-purity intrinsic oxide semiconductors.

[0642] High-purity intrinsic or substantially high-purity intrinsic oxide semiconductor films have a low defect level density, which may result in a low trap level density.

[0643] Charges trapped in the trap levels of oxide semiconductors can take a long time to disappear and sometimes behave like fixed charges. Therefore, transistors in which channel formation regions are formed in oxide semiconductors with a high density of trap levels may exhibit unstable electrical properties.

[0644] Therefore, reducing the impurity concentration in the oxide semiconductor is effective in stabilizing the electrical characteristics of the transistor. Furthermore, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in adjacent films. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, and silicon.

[0645] <Impurities> Here, we will explain the effects of various impurities in oxide semiconductors.

[0646] In oxide semiconductors, the presence of silicon or carbon, which are Group 14 elements, leads to the formation of defect levels 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 2 × 10⁻¹⁰. 18 atoms / cm 3 The following is preferably 2 × 10 17 atoms / cm 3 The following applies:

[0647] When alkali metals or alkaline earth metals are present in oxide semiconductors, they can form defect levels and generate carriers. Therefore, transistors using oxide semiconductors containing alkali metals or alkaline earth metals tend to exhibit normally-on characteristics. For this reason, the concentration of alkali metals or alkaline earth metals in the oxide semiconductor obtained by SIMS should be set to 1 × 10⁻⁶. 18 atoms / cm 3 The following is preferably 2 × 10 16 atoms / cm 3 Do the following:

[0648] In oxide semiconductors, the presence of nitrogen generates electrons, which act as carriers, increasing the carrier concentration and making it easier for the semiconductor to become n-type. As a result, transistors using oxide semiconductors containing nitrogen tend to exhibit normally-on characteristics. Alternatively, the presence of nitrogen in oxide semiconductors can lead to the formation of trap levels. This can result in unstable electrical properties of the transistor. Therefore, the nitrogen concentration in oxide semiconductors obtained by SIMS should be set to 5 × 10⁻¹⁰. 19 atoms / cm 3 Less than 5 × 10 18 atoms / cm 3 More preferably 1 × 10 18 atoms / cm 3 More preferably 5 × 10 17 atoms / cm3 Do the following:

[0649] Hydrogen contained in oxide semiconductors can react with oxygen bonded to metal atoms to form water, potentially creating oxygen vacancies. When hydrogen fills these vacancies, electrons, which act as carriers, can be generated. Furthermore, some of the hydrogen can combine with oxygen bonded to metal atoms to generate electrons. Therefore, transistors using oxide semiconductors containing hydrogen tend to exhibit normally-on characteristics. For this reason, it is preferable to reduce the hydrogen content in oxide semiconductors as much as possible. Specifically, in oxide semiconductors, the hydrogen concentration obtained by SIMS should be 1 × 10⁻⁶. 20 atoms / cm 3 Less than 1 × 10 19 atoms / cm 3 Less than 5x10 18 atoms / cm 3 Less than 1 × 10 18 atoms / cm 3 Make it less than.

[0650] By using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of a transistor, stable electrical characteristics can be provided.

[0651] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0652] (Embodiment 10) This embodiment describes an electronic device comprising a display device and a display system, which are aspects of the present invention.

[0653] Figure 21A shows the external appearance of the head-mounted display 8200.

[0654] The head-mounted display 8200 includes a mounting section 8201, lenses 8202, a main unit 8203, a display unit 8204, a cable 8205, etc. The mounting section 8201 also has a built-in battery 8206.

[0655] Cable 8205 supplies power from battery 8206 to main unit 8203. Main unit 8203 is equipped with a wireless receiver and can display images corresponding to received image data on display unit 8204. In addition, a camera provided on main unit 8203 captures the movement of the user's eyeballs and eyelids, and by calculating the coordinates of the user's gaze based on that information, the user's gaze can be used as an input means.

[0656] The attachment part 8201 may have multiple electrodes positioned to come into contact with the user. The main unit 8203 may have a function to recognize the user's gaze by detecting the current flowing through the electrodes in accordance with the user's eye movements. It may also have a function to monitor the user's pulse by detecting the current flowing through the electrodes. Furthermore, the attachment part 8201 may have various sensors such as a temperature sensor, a pressure sensor, and an acceleration sensor, and may have a function to display the user's biometric information on the display unit 8204. It may also detect the user's head movements and change the image displayed on the display unit 8204 in accordance with those movements.

[0657] A display device according to one embodiment of the present invention can be applied to the display unit 8204. This reduces the power consumption of the head-mounted display 8200, allowing it to 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, thus making the head-mounted display 8200 smaller and lighter. This reduces the burden on the user of the head-mounted display 8200, making it less likely for the user to experience fatigue.

[0658] Figures 21B, 21C, and 21D show the external appearance of the head-mounted display 8300. The head-mounted display 8300 comprises a housing 8301, a display unit 8302, a band-shaped fixing device 8304, and a pair of lenses 8305. The housing 8301 also has a built-in battery 8306, which can supply power to the display unit 8302 and other components.

[0659] The user can view the display on the display unit 8302 through the lens 8305. It is preferable to position the display unit 8302 in a curved shape. By positioning the display unit 8302 in a curved shape, the user can experience a high degree of realism. In this embodiment, a configuration with one display unit 8302 has been illustrated, but the system is not limited to this, and for example, a configuration with two display units 8302 may be used. In this case, if one display unit is positioned for each eye of the user, it becomes possible to perform 3D display using parallax, etc.

[0660] Furthermore, a display device according to one embodiment of the present invention can be applied to the display unit 8302. This reduces the power consumption of the head-mounted display 8300, allowing it to be used continuously for a long period of time. In addition, by reducing the power consumption of the head-mounted display 8300, the battery 8306 can be made smaller and lighter, thus making the head-mounted display 8300 smaller and lighter. This reduces the burden on the user of the head-mounted display 8300, making it less likely for the user to feel fatigued.

[0661] Next, Figures 22A and 22B show the electronic equipment shown in Figures 21A to 21D, as well as an example of a different electronic equipment.

[0662] The electronic device shown in Figures 22A and 22B includes a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), connection terminals 9006, sensors 9007 (including functions for measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation), and a battery 9009, etc.

[0663] The electronic devices shown in Figures 22A and 22B have various functions. For example, they may have functions to display various information (still images, videos, text images, etc.) on the display unit, a touch panel function, a function to display a calendar, date, or time, a function to control processing by various software (programs), a wireless communication function, a function to connect to various computer networks using the wireless communication function, a function to transmit 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. However, the functions that the electronic devices shown in Figures 22A and 22B may have are not limited to these and can have various functions. In addition, although not shown in Figures 22A and 22B, the electronic devices may have a configuration with multiple display units. Furthermore, the electronic devices may be equipped with a camera, etc., and have functions to take still images, take videos, save the captured images to a recording medium (external or built into the camera), and display the captured images on the display unit, etc.

[0664] The details of the electronic equipment shown in Figures 22A and 22B will be explained below.

[0665] Figure 22A is a perspective view showing a personal digital information terminal (PDI) 9101. The PDI 9101 has one or more functions selected from, for example, a telephone, a notebook, or an information viewing device. Specifically, it can be used as a smartphone. The PDI 9101 can also display text or images on multiple surfaces. For example, three operation buttons 9050 (also called operation icons or simply icons) can be displayed on one surface of the display unit 9001. Information 9051, shown by a dashed rectangle, can also be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of incoming emails or SNS (Social Networking Service) messages or phone calls, the subject of emails or SNS messages, the sender's name of emails or SNS messages, the date and time, the battery level, the antenna signal strength, etc. Alternatively, operation buttons 9050, etc., may be displayed in place of the information 9051.

[0666] A display device according to one aspect of the present invention can be applied to the personal information terminal 9101. This reduces the power consumption of the personal information terminal 9101, allowing it to be used continuously for a long period of time. Furthermore, by reducing the power consumption of the personal information terminal 9101, the battery 9009 can be made smaller and lighter, thus making the personal information terminal 9101 smaller and lighter. This improves the portability of the personal information terminal 9101.

[0667] Figure 22B is a perspective view showing a wristwatch-type personal information terminal 9200. The personal information terminal 9200 can run various applications such as mobile phone calls, email, document viewing and creation, music playback, internet communication, and computer games. The display unit 9001 has a curved display surface, allowing it to display information along the curved surface. Figure 22B shows an example where the time 9251, operation buttons 9252 (also called operation icons or simply icons), and content 9253 are displayed on the display unit 9001. The content 9253 can be, for example, a video.

[0668] Furthermore, the personal information terminal 9200 is capable of performing standardized short-range wireless communication. For example, it can communicate with a wireless communication-enabled headset to make hands-free calls. The personal information terminal 9200 also has a connection terminal 9006, which allows it to directly exchange data with other information terminals via a connector. It can also be charged via the connection terminal 9006. However, charging may be performed by wireless power supply without using the connection terminal 9006.

[0669] A display device according to one aspect of the present invention can be applied to the personal information terminal 9200. This reduces the power consumption of the personal information terminal 9200, allowing it to be used continuously for a long period of time. Furthermore, by reducing the power consumption of the personal information terminal 9200, the battery 9009 can be made smaller and lighter, thus making the personal information terminal 9200 smaller and lighter. This improves the portability of the personal information terminal 9200.

[0670] This embodiment can be implemented in appropriate combination with other embodiments described herein, at least in part.

[0671] <Notes regarding the description in this specification, etc.> The above embodiments and a description of each component in those embodiments are provided below.

[0672] The configurations shown in each embodiment can be appropriately combined with the configurations shown in other embodiments to form one aspect of the present invention. Furthermore, if multiple configuration examples are shown within a single embodiment, these configuration examples can be appropriately combined.

[0673] Furthermore, the content described in one embodiment (even if only a part of it) can be applied to, combined with, or substituted for other content described in the same embodiment (even if only a part of it), and / or content described in one or more other embodiments (even if only a part of it).

[0674] The content described in the embodiments refers to the content described using various figures or the content described using text in the specification in each embodiment.

[0675] Furthermore, a diagram (even a part of it) described in one embodiment can be combined with another part of that diagram, another diagram (even a part of it) described in that embodiment, and / or a diagram (even a part of it) described in one or more other embodiments to form even more diagrams.

[0676] Furthermore, in this specification, block diagrams classify components by function and show them as independent blocks. However, in actual circuits, it is difficult to separate components by function, and there may be cases where multiple functions are involved in one circuit, 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, and can be appropriately rephrased depending on the situation.

[0677] Furthermore, in the drawings, the size, layer thickness, or area are shown at arbitrary sizes for the sake of explanation. Therefore, they are not necessarily limited to that scale. Also, the drawings are schematic for clarity and are not limited to the shapes or values ​​shown in the drawings. For example, they may include variations in signals, voltages, or currents due to noise, or variations in signals, voltages, or currents due to timing differences.

[0678] In this specification and other documents, when describing the connections 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 transistor's structure or operating conditions. The terms source and drain of a transistor can be appropriately rephrased as source (drain) terminal or source (drain) electrode, depending on the context.

[0679] Furthermore, the terms "electrode" and "wiring" in this specification do not functionally limit these components. For example, "electrode" may be used as part of "wiring," and vice versa. Moreover, the terms "electrode" and "wiring" also include cases where multiple "electrodes" or "wiring" are formed as a single unit.

[0680] Furthermore, in this specification, voltage and potential may be used interchangeably as appropriate. Voltage is the potential difference from a reference potential; for example, if the reference potential is the ground voltage (earth voltage), then voltage can be replaced with potential. Ground potential does not necessarily mean 0V. Note that potential is relative, and depending on the reference potential, it may change the potential applied to wiring, etc.

[0681] In this specification, terms such as "film" and "layer" may be interchanged depending on the context or situation. For example, the term "conductive layer" may be changed to "conductive film." Or, for example, the term "insulating film" may be changed to "insulating layer."

[0682] In this specification, a switch refers to a device that has the function of controlling whether or not to allow current to flow by being in a conductive state (on state) or a non-conductive state (off state). Alternatively, a switch refers to a device that has the function of selecting and switching the path through which current flows.

[0683] In this specification, channel length refers, for example, to the distance between the source and drain in the region where the semiconductor (or the part of the semiconductor through which current flows when the transistor is ON) and the gate overlap in a top view of a transistor, or in the region where the channel is formed.

[0684] In this specification, channel width refers, for example, to the length of the region where the semiconductor (or the part of the semiconductor through which current flows when the transistor is ON) and the gate electrode overlap, or the region in which the channel is formed, where the source and drain face each other.

[0685] In this specification, "A and B are connected" includes not only those that are directly connected, but also those that are electrically connected. Here, "electrically connected" means that when there is an object between A and B that has some kind of electrical effect, it enables the exchange of electrical signals between A and B. [Examples]

[0686] In this embodiment, a light-emitting device that can be used in a display device according to one aspect of the present invention will be described with reference to Figures 23 to 39.

[0687] Figures 23A and 23B illustrate the configuration of the light-emitting device 550.

[0688] Figure 24 illustrates the current density-luminance characteristics of the light-emitting device 1.

[0689] Figure 25 illustrates the luminance-current efficiency characteristics of the light-emitting device 1.

[0690] Figure 26 illustrates the voltage-luminance characteristics of the light-emitting device 1.

[0691] Figure 27 illustrates the voltage-current characteristics of the light-emitting device 1.

[0692] Figure 28 is a diagram for explaining the emission spectrum when the light-emitting device 1 emits light at a luminance of 1000 cd / m 2 .

[0693] Figure 29 is a diagram for explaining the current density-luminance characteristics of the light-emitting device 2.

[0694] Figure 30 is a diagram for explaining the luminance-current efficiency characteristics of the light-emitting device 2.

[0695] Figure 31 is a diagram for explaining the voltage-luminance characteristics of the light-emitting device 2.

[0696] Figure 32 is a diagram for explaining the voltage-current characteristics of the light-emitting device 2.

[0697] Figure 33 is a diagram for explaining the emission spectrum when the light-emitting device 2 emits light at a luminance of 1000 cd / m 2 .

[0698] Figure 34 is a diagram for explaining the current density-luminance characteristics of the light-emitting device 3 and the light-emitting device 4.

[0699] Figure 35 is a diagram for explaining the luminance-current efficiency characteristics of the light-emitting device 3 and the light-emitting device 4.

[0700] Figure 36 is a diagram for explaining the voltage-luminance characteristics of the light-emitting device 3 and the light-emitting device 4.

[0701] Figure 37 is a diagram for explaining the voltage-current characteristics of the light-emitting device 3 and the light-emitting device 4.

[0702] Figure 38 is a diagram for explaining the luminance-blue index characteristics of the light-emitting device 3 and the light-emitting device 4.

[0703] Figure 39 is a diagram for explaining the emission spectrum when the light-emitting device 3 and the light-emitting device 4 emit light at a luminance of 千000 cd / m 2 .

[0704] Figures 40A to 40D illustrate the configuration of the light-emitting device 550.

[0705] Figure 41 illustrates the current density-luminance characteristics of the light-emitting device 5.

[0706] Figure 42 illustrates the luminance-current efficiency characteristics of the light-emitting device 5.

[0707] Figure 43 illustrates the voltage-luminance characteristics of the light-emitting device 5.

[0708] Figure 44 illustrates the voltage-current characteristics of the light-emitting device 5.

[0709] Figure 45 shows the light-emitting device 5 at 1000 cd / m². 2 This diagram illustrates the emission spectrum when the light source is emitted at a specific brightness level.

[0710] Figure 46 shows a constant current density (50 mA / cm²). 2 This figure illustrates the change over time in the normalized brightness of the light-emitting device 5 when it is illuminated by ).

[0711] <Light-emitting device 1> The light-emitting device 1 described in this embodiment can be used in a display device according to one aspect of the present invention. The light-emitting device 1 has the same configuration as the light-emitting device 550 (see Figure 23A).

[0712] Configuration of Light-Emitting Device 1 Table 1 shows the configuration of the light-emitting device 1. The structural formulas of the materials used in the light-emitting device described in this embodiment are shown below. In the table of this embodiment, subscripts and superscripts are written in standard size for convenience. For example, subscripts used in abbreviations and superscripts used in units are written in standard size in the table. These descriptions in the table can be interpreted in reference to the description in the specification. In addition, in the light-emitting device 1, the reflective film REFG(2) has a distance DG of 112 nm between it and the electrode 552G.

[0713] [Table 1]

[0714] [ka]

[0715] 《Method for fabricating light-emitting device 1》 The light-emitting device 1 described in this embodiment was fabricated using a method comprising the following steps.

[0716] [Step 1] In the first step, a conductive film REFG(1) was formed. Specifically, it was formed by sputtering using titanium (Ti) as the target.

[0717] The conductive film REFG(1) contains Ti and has a thickness of 50 nm.

[0718] [Step 2] In the second step, a reflective film REFG(2) was formed on the conductive film REFG(1). Specifically, it was formed by sputtering using aluminum (Al) as the target.

[0719] The reflective film REFG(2) contains Al and has a thickness of 70 nm.

[0720] [Step 3] In the third step, a conductive film REFG(3) was formed on the reflective film REFG(2). Specifically, it was formed by sputtering using Ti as the target.

[0721] The conductive film REFG(3) contains Ti and has a thickness of 6 nm.

[0722] [Step 4] In the first step, electrode 551G was formed. Specifically, it was formed by sputtering using indium tin oxide (ITSO), which contains silicon or silicon oxide, as the target.

[0723] The electrode 551G contains ITSO and has a thickness of 10 nm and 4 mm 2 It has an area of ​​(2mm x 2mm).

[0724] Next, the substrate on which electrode 551G was formed was washed with water, fired at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds. After that, 10 -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa, and vacuum firing was performed at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus. After that, the substrate was allowed to cool for about 30 minutes.

[0725] [Step 5] In the fifth step, layer 104 was formed on electrode 551G. Specifically, the material was co-deposited using resistance heating.

[0726] Layer 104 contains N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBBiF) and an electron-accepting material (OCHD-003) in a weight ratio of PCBBiF:OCHD-003 = 1:0.03, and has a thickness of 10 nm. The electron-accepting material OCHD-003 contains fluorine and has a molecular weight of 672.

[0727] [Step 6] In the sixth step, layer 112 was formed on layer 104. Specifically, the material was deposited using a resistance heating method.

[0728] Layer 112 contains PCBBiF and has a thickness of 10 nm.

[0729] [Step 7] In the seventh step, layer 111G was formed on layer 112. Specifically, the material was co-deposited using the resistance heating method.

[0730] Layer 111G contains 8-(1,1'-biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzoflo[3,2-d]pyrimidine (abbreviated as 8BP-4mDBtPBfpm), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviated as PCCP), and [2-d3-methyl-(2-pyridinyl-κN)benzoflo[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviated as Ir(ppy)2(mbfpypy-d3)) in a weight ratio of 8BP-4mDBtPBfpm:PCCP:Ir(ppy)2(mbfpypy-d3) = 0.6:0.4:0.1 and has a thickness of 40 nm.

[0731] [Step 8] In the eighth step, layer 113(1) was formed on layer 111G. Specifically, the material was deposited using the resistance heating method.

[0732] Layer 113(1) contains 2-[3-(3'-dibenzothiophen-4-yl)biphenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II) and has a thickness of 15 nm.

[0733] [Step 9] In the ninth step, layer 113(2) was formed on layer 113(1). Specifically, the material was deposited using a resistance heating method.

[0734] Layer 113(2) contains 2,9-di(2-naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen) and has a thickness of 15 nm.

[0735] [Step 10] In the tenth step, layer 105 was formed on layer 113(2). Specifically, the material was deposited using a resistance heating method.

[0736] Layer 105 contains lithium fluoride (abbreviated as LiF) and has a thickness of 1 nm.

[0737] [Step 11] In the 11th step, electrode 552G was formed on layer 105. Specifically, the material was co-deposited using resistance heating.

[0738] The electrode 552G contains silver (abbreviated as Ag) and magnesium (abbreviated as Mg) in an Ag:Mg = 1:0.1 (volume ratio) and has a thickness of 25 nm.

[0739] [Step 12] In the twelfth step, a conductive film 552 was formed on the electrode 552G. Specifically, it was formed by sputtering using indium tin oxide (ITO) as the target.

[0740] The conductive film 552 contains ITO and has a thickness of 70 nm.

[0741] Operating characteristics of the light-emitting device 1 When power was supplied, the light-emitting device 1 emitted light EL1 (see Figure 23A). The operating characteristics of the light-emitting device 1 were measured at room temperature (see Figures 24 to 28). A spectroradiometer (Topcon SR-UL1R) was used to measure luminance, CIE chromaticity, and emission spectrum.

[0742] The fabricated light-emitting device has a brightness of 1000 cd / m². 2 Table 2 shows the main initial characteristics when the device is illuminated to a certain degree. The distances in the table refer to the distance from the reflective film REFG(2) to electrode 552G, the distance from the reflective film REFR(2) to electrode 552R, or the distance from the reflective film REFB(2) to electrode 552B. The characteristics of other light-emitting devices and comparison devices, described later, are also shown.

[0743] The Blue Index (BI) is one of the indicators that represent the characteristics of a blue light-emitting device, and it is the value obtained by dividing the current efficiency (cd / A) by the y-chromaticity. Generally, blue light with high color purity is useful for representing a wide color gamut. Also, the higher the color purity of the blue light, the lower the y-chromaticity tends to be. Therefore, the value obtained by dividing the current efficiency (cd / A) by the y-chromaticity serves as an indicator of the usefulness of a blue light-emitting device. In other words, a blue light-emitting device with a high BI is suitable for realizing a display device that has a wide color gamut and high efficiency.

[0744] [Table 2]

[0745] The light-emitting device 1 was found to exhibit excellent characteristics. For example, light-emitting device 1 can be driven at a lower voltage than comparison device 1. Furthermore, it can achieve higher brightness with less power than comparison device 1. Additionally, light-emitting device 1 uses less material than comparison device 1. Moreover, the manufacturing time can be reduced.

[0746] (Reference example 1) The comparative device 1 described in this reference example differs from the light-emitting device 1 in that layer 112 has a thickness of 137.5 nm instead of 10 nm, layer 111G has a thickness of 50 nm instead of 40 nm, and layer 105 contains LiF and Yb in a LiF:Yb=1:1 (weight ratio) instead of LiF and has a thickness of 1.8 nm. In addition, electrode 552G has a thickness of 15 nm instead of 25 nm. In comparative device 1, the reflective film REFG(2) has a distance DG of 250.3 nm between it and electrode 552G.

[0747] <Light-emitting device 2> The light-emitting device 2 described in this embodiment can be used in a display device according to one aspect of the present invention.

[0748] Configuration of Light-Emitting Device 2 Table 3 shows the configuration of the light-emitting device 2. The structural formulas of the materials used in the light-emitting device described in this embodiment are shown below. In the light-emitting device 2, the reflective film REFR(2) has a distance DR of 137 nm between it and the electrode 552R.

[0749] [Table 3]

[0750] [ka]

[0751] The configuration of light-emitting device 2 differs from light-emitting device 1 in that it has electrode 551R instead of electrode 551G, layer 112 has a thickness of 30 nm instead of 10 nm, layer 111R instead of layer 111G, layer 113(2) has a thickness of 20 nm instead of 15 nm, and electrode 552R instead of electrode 552G.

[0752] 《Method for fabricating light-emitting device 2》 The light-emitting device 2 described in this embodiment was fabricated using a method comprising the following steps.

[0753] Note that the method for fabricating the light-emitting device 2 differs from the method for fabricating the light-emitting device 1 in the sixth step of forming layer 112, the seventh step of forming layer 111R, and the ninth step of forming layer 113(2). Here, the differences will be explained in detail, and the above explanation will be used as a reference for parts where the same method is used.

[0754] [Step 6] In the sixth step, layer 112 was formed on layer 104. Specifically, the material was deposited using a resistance heating method.

[0755] Layer 112 contains PCBBiF and has a thickness of 30 nm.

[0756] [Step 7] In the seventh step, layer 111R was formed on layer 112. Specifically, the material was co-deposited using the resistance heating method.

[0757] Layer 111R contains 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]flo[2,3-b]pyrazine (abbreviated as 9mDBtBPNfpr), PCBBiF, and phosphorescent dopant (abbreviated as OCPG-006) in a weight ratio of 9mDBtBPNfpr:PCBBiF:OCPG-006 = 0.6:0.4:0.1, and has a thickness of 40 nm.

[0758] [Step 9] In the ninth step, layer 113(2) was formed on layer 113(1). Specifically, the material was deposited using a resistance heating method.

[0759] Layer 113(2) contains NBPhen and has a thickness of 20 nm.

[0760] Operating characteristics of the light-emitting device 2 When power was supplied, the light-emitting device 2 emitted light EL1 (see Figure 23A). The operating characteristics of the light-emitting device 2 were measured at room temperature (see Figures 29 to 33). A spectroradiometer (Topcon SR-UL1R) was used to measure luminance, CIE chromaticity, and emission spectrum.

[0761] The fabricated light-emitting device has a brightness of 1000 cd / m². 2 Table 2 shows the main initial characteristics when the light was emitted to a certain degree.

[0762] The light-emitting device 2 was found to exhibit superior characteristics. For example, light-emitting device 2 can be driven at a lower voltage than comparison device 2. Furthermore, it can achieve higher brightness with less power than comparison device 2. Additionally, light-emitting device 2 uses less material than comparison device 2. Moreover, the manufacturing time can be reduced.

[0763] In a display device having light-emitting devices 1 and 2, light-emitting device 1 has a distance DG of 112 nm between the reflective film REFG(2) and the electrode 552G. Light-emitting device 2 has a distance DR of 137 nm between the reflective film REFR(2) and the electrode 552R.

[0764] The distance DR at 137nm is 25nm longer than the distance DG at 112nm.

[0765] A display device having light-emitting device 1 and light-emitting device 2 has a smaller step height compared to a display device having comparison device 1 and comparison device 2.

[0766] (Reference example 2) The comparative device 2 fabricated in this reference example differs from light-emitting device 2 in that layer 112 has a thickness of 192.5 nm instead of 30 nm, and layer 105 contains LiF and Yb in a LiF:Yb=1:1 (weight ratio) instead of LiF and has a thickness of 1.8 nm. In addition, electrode 552R has a thickness of 15 nm instead of 25 nm. In comparative device 2, the reflective film REFR(2) has a distance DR of 300.3 nm between it and electrode 552R.

[0767] In a display device having comparison device 1 and comparison device 2, comparison device 1 has a distance DG of 250.3 nm between the reflective film REFG(2) and the electrode 552G. Comparison device 2 has a distance DR of 300.3 nm between the reflective film REFR(2) and the electrode 552R.

[0768] The distance DR at 300.3 nm is 50 nm longer than the distance DG at 250.3 nm.

[0769] <Light-emitting device 3> The light-emitting device 3 described in this embodiment can be used in a display device according to one aspect of the present invention. The light-emitting device 3 has the same configuration as the light-emitting device 550 (see Figure 23B).

[0770] Configuration of Light-Emitting Device 3 Table 4 shows the configuration of the light-emitting device 3. The structural formulas of the materials used in the light-emitting device described in this embodiment are shown below. In the light-emitting device 3, the reflective film REFB(2) has a distance DB of 193.8 nm between it and the electrode 552B.

[0771] [Table 4]

[0772] [ka]

[0773] The configuration of the light-emitting device 3 differs from that of the light-emitting device 1 in that it includes electrode 551B instead of electrode 551G, layers 112(1) and 112(2) instead of layer 112, layer 111B instead of layer 111G, layer 105 contains LiF and Yb in a 1:1 (weight ratio) ratio instead of LiF and has a thickness of 1.8 nm, and electrode 552B instead of electrode 552G. Conductive film REFB(1) has the same configuration as conductive film REFG(1), and conductive film REFB(3) has the same configuration as conductive film REFG(3).

[0774] 《Method for fabricating light-emitting device 3》 The light-emitting device 3 described in this embodiment was fabricated using a method comprising the following steps.

[0775] Note that the method for fabricating the light-emitting device 3 differs from the method for fabricating the light-emitting device 1 in the following steps: the sixth step of forming layer 112(1) instead of layer 112, the sixth-second step of forming layer 112(2) on layer 112(1), the seventh step of forming layer 111B, and the tenth step of forming layer 105. Here, the differences will be explained in detail, and the above explanation will be used as a reference for parts where the same method is used.

[0776] [Step 6] In the sixth step, layer 112(1) was formed on layer 104. Specifically, the material was deposited using a resistance heating method.

[0777] Layer 112(1) contains PCBBiF and has a thickness of 96 nm.

[0778] [Step 6-2] In step 6-2, layer 112(2) was formed on layer 112(1). Specifically, the material was deposited using the resistance heating method.

[0779] Layer 112(2) contains N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP) and has a thickness of 10 nm.

[0780] [Step 7] In the seventh step, layer 111B was formed on layer 112(2). Specifically, the material was co-deposited using the resistance heating method.

[0781] Layer 111B contains 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviated as αN-βNPAnth) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 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.

[0782] [Step 10] In the tenth step, layer 105 was formed on layer 113(2). Specifically, the material was co-deposited using the resistance heating method.

[0783] Layer 105 contains LiF and Yb in a LiF:Yb ratio of 1:1 (by weight) and has a thickness of 1.8 nm.

[0784] Operating characteristics of the light-emitting device 3 When power is supplied, the light-emitting device 3 emits light EL1 (see FIG. 23B). The operating characteristics of the light-emitting device 1 were measured at room temperature (see FIGS. 34 to 39). A spectro-radiometer (SR-UL1R, manufactured by Topcon Corporation) was used to measure the luminance, CIE chromaticity, and emission spectrum.

[0785] When the fabricated light-emitting device was caused to emit light at a luminance of about 1000 cd / m 2 The results of the main initial characteristics are shown in Table 2.

[0786] It was found that the light-emitting device 3 exhibited good characteristics. For example, the light-emitting device 3 emitted light showing a deep blue chromaticity. Also, since it shows a high blue index, it can be said that it is a device suitable for a display device.

[0787] In a display device having the light-emitting device 1, the light-emitting device 2, and the light-emitting device 3, the light-emitting device 1 has a distance DG of 112 nm between the reflective film REF G(2) and the electrode 552G. Also, the light-emitting device 2 ha...

Claims

[Claim 1] A first light-emitting device and A second light-emitting device, insulating film and conductive film and, The first reflective film, The second reflective layer, It has a first layer, The first light-emitting device comprises a first electrode, a second electrode, and a first unit. The first unit is sandwiched between the first electrode and the second electrode, The first electrode is sandwiched between the first unit and the insulating film. The first layer is sandwiched between the first unit and the first electrode. The first layer comprises an electron-accepting material and a hole-transporting material, The first layer is 1 × 10 ２ [Ω・cm] or more 1×10 ８ Having an electrical resistivity of [Ω・cm] or less, The second light-emitting device comprises a third electrode, a fourth electrode, and a second unit. The second unit is sandwiched between the third electrode and the fourth electrode, The third electrode is sandwiched between the second unit and the insulating film. The third electrode has a first gap between it and the first electrode, The conductive film electrically connects the second electrode and the fourth electrode. The first gap is sandwiched between the conductive film and the insulating film. The first reflective film is sandwiched between the first electrode and the insulating film. The first reflective film has a first distance DR between it and the second electrode, The second reflective film is sandwiched between the third electrode and the insulating film. The second reflective film has a second distance DG between it and the fourth electrode, A display device wherein the second distance DG is in a relationship with the first distance DR that satisfies the following formulas (1) to (3). [Math 1]

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