Display device

Abstract

Provided is a highly reliable display device. The display device comprises a transistor on a substrate, a first insulating layer on the transistor, a second insulating layer on the first insulating layer, a plug disposed so as to be embedded in the first insulating layer and the second insulating layer, and a light emitting element on the second insulating layer, wherein: the light emitting element comprises a first conductive layer, an EL layer on the first conductive layer, and a second conductive layer on the EL layer; the plug electrically connects one of the source and the drain of the transistor to the first conductive layer; and the second insulating layer has a higher ability to suppress diffusion of hydrogen than the first insulating layer.

Description

display device

[0001] 1. Field of the Invention One embodiment of the present invention relates to a display device and a display module. 2. Description of the Related Art One embodiment of the present invention relates to a manufacturing method of a display device.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention disclosed in this specification and the like include semiconductor devices, display devices, light-emitting devices, power storage devices, memory devices, electronic devices, lighting devices, input devices, input / output devices, driving methods thereof, and manufacturing methods thereof. Note that in this specification and the like, a semiconductor device refers to any device that can function by utilizing semiconductor characteristics.

[0003] In recent years, there has been a demand for higher definition display panels. Devices requiring high-definition display panels, such as devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), or mixed reality (MR), have been actively developed in recent years.

[0004] Representative examples of display devices applicable to the display panel include liquid crystal display devices, organic EL (Electro Luminescence) elements, light-emitting devices equipped with light-emitting elements such as light-emitting diodes (LEDs: Light Emitting Diodes), and electronic paper that displays using an electrophoresis method.

[0005] For example, the basic structure of an organic EL element is a layer containing a light-emitting organic compound sandwiched between a pair of electrodes. By applying a voltage to this element, light can be emitted from the light-emitting organic compound. A display device using such an organic EL element does not require a backlight, which is necessary in liquid crystal display devices and the like, and therefore can realize a thin, lightweight, high-contrast, and low-power display device. For example, an example of a display device using an organic EL element is described in Patent Document 1.

[0006] JP 2002-324673 A

[0007] For example, in the wearable devices for VR, AR, SR, or MR described above, a focus adjustment lens must be provided between the eyes and the display panel, which enlarges part of the screen, resulting in a problem that if the resolution of the display panel is low, the sense of reality and immersion will be diminished.

[0008] Furthermore, display panels are required to have high color reproducibility. In particular, in the above-mentioned devices for VR, AR, SR, or MR, by using a display panel with high color reproducibility, it is possible to display colors that are close to the colors of real objects, thereby enhancing the sense of realism and immersion.

[0009] An object of one embodiment of the present invention is to provide a display device with extremely high resolution.An object of one embodiment of the present invention is to provide a display device with high reliability.An object of one embodiment of the present invention is to provide a display device with high color reproducibility.An object of one embodiment of the present invention is to provide a display device with high luminance.An object of one embodiment of the present invention is to provide a method for manufacturing the above-described display device.

[0010] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these can be extracted from the description of the specification, drawings, claims, etc.

[0011] One embodiment of the present invention is a display device that includes a transistor over a substrate, a first insulating layer over the transistor, a second insulating layer over the first insulating layer, a plug disposed so as to be embedded in the first insulating layer and the second insulating layer, and a light-emitting element over the second insulating layer, wherein the light-emitting element includes a first conductive layer, an EL layer over the first conductive layer, and a second conductive layer over the EL layer, the plug electrically connects one of a source and a drain of the transistor to the first conductive layer, and the second insulating layer has a higher ability to suppress hydrogen diffusion than the first insulating layer.

[0012] In the above structure, the second insulating layer preferably contains nitrogen and silicon.

[0013] In the above structure, it is preferable that the second insulating layer has a first layer and a second layer on the first layer, the first layer has nitrogen and silicon, and the second layer has oxygen and aluminum.

[0014] In the above structure, it is preferable that the second insulating layer has a first layer and a second layer on the first layer, the first layer has nitrogen and silicon, and the second layer has oxygen and hafnium.

[0015] In the above structure, it is preferable that a third insulating layer be disposed to cover the light emitting element, and that the third insulating layer have a higher ability to suppress hydrogen diffusion than the first insulating layer.

[0016] In the above structure, the third insulating layer is preferably in contact with the second insulating layer in a region that does not overlap with the light-emitting element.

[0017] In the above structure, it is preferable that the third insulating layer has a third layer and a fourth layer on the third layer, the third layer has oxygen and aluminum, and the fourth layer has nitrogen and silicon.

[0018] In the above structure, the EL layer preferably covers a side surface of the first conductive layer.

[0019] In the above structure, it is preferable that an insulator is disposed between the EL layer and the first conductive layer, the insulator has an opening on the first conductive layer, and the EL layer and the first conductive layer are in contact with each other through the opening.

[0020] In the above structure, the first conductive layer preferably has a reflectivity to visible light, and the second conductive layer preferably has a transmissivity and a reflectivity to visible light.

[0021] In the above structure, the substrate is preferably a silicon substrate, and the transistor preferably has silicon in a channel formation region.

[0022] In the above structure, it is preferable that an oxide semiconductor film be provided over the substrate, and that the transistor have the oxide semiconductor film in a channel formation region.

[0023] According to one aspect of the present invention, it is possible to provide a display device with extremely high resolution, a highly reliable display device, a display device with high color reproducibility, a high brightness display device, or a method for manufacturing the display device.

[0024] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these can be extracted from the description in the specification, drawings, claims, etc.

[0025] FIGS. 1A to 1C are diagrams illustrating a structural example of a display device. FIGS. 2A and 2B are diagrams illustrating a structural example of a display device. FIGS. 3A and 3B are diagrams illustrating a structural example of a display device. FIGS. 4A and 4B are diagrams illustrating a structural example of a display device. FIGS. 5A to 5E are diagrams illustrating a manufacturing method example of a display device. FIGS. 6A to 6D are diagrams illustrating a manufacturing method example of a display device. FIG. 7 is a diagram illustrating a structural example of a display device. FIG. 8 is a diagram illustrating a structural example of a display device. FIG. 9 is a diagram illustrating a structural example of a display device. FIG. 10 is a diagram illustrating a structural example of a display device. FIGS. 11A and 11B are diagrams illustrating a structural example of a display module. FIGS. 12A and 12B are circuit diagrams illustrating an example of a display device. FIGS. 13A and 13C are circuit diagrams illustrating an example of a display device. FIG. 13B is a timing chart illustrating an operation example of a display device. FIGS. 14A and 14B are diagrams illustrating structural examples of electronic devices. FIGS. 15A and 15B are diagrams illustrating structural examples of electronic devices. FIGS. 16A to 16C are diagrams illustrating structural examples of a display device. 17A and 17B are diagrams showing the structure of a sample of this example, and FIGS. 18A and 18B are diagrams showing the results of this example.

[0026] Hereinafter, embodiments will be described with reference to the drawings. However, it will be readily understood by those skilled in the art that the embodiments can be implemented in many different ways and that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the following description of the embodiments.

[0027] In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and repeated explanations thereof will be omitted. In addition, when referring to similar functions, the same hatch pattern may be used and no particular reference numeral may be assigned.

[0028] In the drawings described in this specification, the size of each component, the thickness of a layer, or an area may be exaggerated for clarity, and therefore, the drawings are not necessarily limited to the scale.

[0029] In this specification, ordinal numbers such as "first" and "second" are used to avoid confusion of components and do not limit the number.

[0030] Embodiment 1 In this embodiment, a display device according to one embodiment of the present invention and a method for manufacturing the display device will be described.

[0031] A display device according to one embodiment of the present invention includes light-emitting elements (also referred to as light-emitting devices) that emit light of different colors. The light-emitting elements include a lower electrode, an upper electrode, and a light-emitting layer (also referred to as a layer containing a light-emitting compound) between them. As the light-emitting elements, electroluminescent elements such as organic EL elements and inorganic EL elements are preferably used. Alternatively, light-emitting diodes (LEDs) may be used.

[0032] The EL element can be an organic light-emitting diode (OLED), a quantum-dot light-emitting diode (QLED), or the like. Examples of light-emitting compounds (also referred to as light-emitting substances) included in the EL element include fluorescent materials, phosphorescent materials, inorganic compounds (such as quantum dot materials), and thermally activated delayed fluorescence (TADF) materials.

[0033] As the light-emitting substance, a substance that emits light of blue, purple, blue-purple, green, yellow-green, yellow, orange, red, etc. may be appropriately used. A substance that emits near-infrared light may also be used.

[0034] The light-emitting layer may contain one or more compounds (host material, assist material) in addition to the light-emitting substance (guest material). As the host material and the assist material, one or more substances having an energy gap larger than the energy gap of the light-emitting substance (guest material) can be selected and used. As the host material and the assist material, it is preferable to use a combination of compounds that form an exciplex. In order to efficiently form an exciplex, it is particularly preferable to combine a compound that easily accepts holes (hole-transporting material) with a compound that easily accepts electrons (electron-transporting material).

[0035] The light-emitting element can be made of either a low molecular weight compound or a high molecular weight compound, and may contain an inorganic compound (such as a quantum dot material).

[0036] The display device according to one embodiment of the present invention can produce light-emitting elements of different colors with extremely high precision. Therefore, a display device with higher resolution than conventional display devices can be realized. For example, it is preferable that the display device is an extremely high-resolution display device in which pixels each having one or more light-emitting elements are arranged at a resolution of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and 20000 ppi or less, or 30000 ppi or less.

[0037] More specific configuration examples and manufacturing method examples will be described below with reference to the drawings.

[0038] 1A is a cross-sectional schematic diagram illustrating a display device of one embodiment of the present invention. The display device 100 includes a light-emitting element 120R, a light-emitting element 120G, and a light-emitting element 120B. The light-emitting element 120R is a light-emitting element that emits red light, the light-emitting element 120G is a light-emitting element that emits green light, and the light-emitting element 120B is a light-emitting element that emits blue light.

[0039] In the following, when describing matters common to the light-emitting element 120R, the light-emitting element 120G, and the light-emitting element 120B, symbols added to the reference numerals may be omitted and the light-emitting element 120 may be referred to as such. The EL layer 115R, the EL layer 115G, and the EL layer 115B described below may also be referred to as such. The EL layer 115R is included in the light-emitting element 120R. Similarly, the EL layer 115G is included in the light-emitting element 120G, and the EL layer 115B is included in the light-emitting element 120B. The conductive layer 114R, the conductive layer 114G, and the conductive layer 114B described below may also be referred to as such. The conductive layer 114R is included in the light-emitting element 120R. Similarly, the conductive layer 114G is included in the light-emitting element 120G, and the conductive layer 114B is included in the light-emitting element 120B.

[0040] The light-emitting element 120 includes a conductive layer 111 functioning as a lower electrode, an EL layer 115, and a conductive layer 116 functioning as an upper electrode. The conductive layer 111 is reflective to visible light. The conductive layer 116 is transmissive and reflective to visible light. Alternatively, the conductive layer 116 may be semi-transmissive and semi-reflective to visible light. The EL layer 115 includes a light-emitting compound. The EL layer 115 includes at least the light-emitting layer included in the light-emitting element 120.

[0041] The light-emitting element 120 can be an electroluminescent element that emits light in response to a current flowing through the EL layer 115 when a potential difference is applied between the conductive layer 111 and the conductive layer 116. In particular, it is preferable to use an organic EL element that uses a light-emitting organic compound for the EL layer 115. Furthermore, it is preferable that the light-emitting element 120 is an element that emits white light whose emission spectrum has two or more peaks in the visible light region.

[0042] The surface of the conductive layer 111 is reflective to visible light.

[0043] The display device 100 includes a substrate 101 having a semiconductor circuit, and a light-emitting element 120 on the substrate 101. The display device 100 shown in FIG. 1A also includes an insulating layer 121 on the substrate 101, an insulating layer 122 on the insulating layer 121, and the light-emitting element 120 on the insulating layer 122.

[0044] The substrate 101 can be a circuit substrate having transistors, wirings, and the like. When a passive matrix system or a segment system is applicable, an insulating substrate such as a glass substrate can be used as the substrate 101. The substrate 101 is provided with a circuit (also referred to as a pixel circuit) for driving each light-emitting element. The substrate 101 may also be provided with a semiconductor circuit that functions as a driver circuit for driving the pixel circuit. The semiconductor elements constituting such a pixel circuit or semiconductor circuit may be formed using a semiconductor substrate such as a single crystal silicon substrate or an oxide semiconductor film. A more specific example of the structure of the substrate 101 will be described later.

[0045] In the display device 100 shown in FIG. 1A , the substrate 101 and the conductive layer 111 of the light-emitting element 120 are electrically connected via a plug 131. The plug 131 is formed so as to be embedded in an opening provided in the insulating layer 121 and the insulating layer 122. The conductive layer 111 is formed on the insulating layer 122. The conductive layer 111 is provided on the plug 131. The conductive layer 111 and the plug 131 are electrically connected. Furthermore, it is preferable that the conductive layer 111 be in contact with the upper surface of the plug 131. Furthermore, the conductive layer 111 may be configured to be in contact with the upper surface of the insulating layer 122.

[0046] The insulating layer 122 preferably functions as a barrier insulating film against impurities such as hydrogen. The insulating layer 122 is preferably a barrier insulating film against hydrogen or a substance to which hydrogen is bonded (for example, water (H ２ The insulating layer 122 has a function of suppressing the diffusion of at least one of hydrogen and hydrogen-bonded substances, such as oxygen. Therefore, the insulating layer 122 has a higher ability to suppress the diffusion of at least one of hydrogen and hydrogen-bonded substances than the insulating layer 121. Alternatively, the insulating layer 122 preferably has a function of capturing or fixing (also referred to as gettering) at least one of hydrogen and hydrogen-bonded substances. Therefore, the insulating layer 122 preferably has a higher ability to capture or fix at least one of hydrogen and hydrogen-bonded substances than the insulating layer 121. Furthermore, the insulating layer 122 may function as a barrier insulating film against oxygen.

[0047] In this specification, a barrier insulating film refers to an insulating film having barrier properties. In this specification, the barrier properties refer to a function of suppressing the diffusion of a corresponding substance (also referred to as low permeability) or a function of capturing or fixing a corresponding substance (also referred to as gettering).

[0048] In a display device according to one embodiment of the present invention, a barrier insulating film against water, hydrogen, or the like is provided under a light-emitting element, thereby preventing impurities such as water or hydrogen contained in an interlayer insulating film and a semiconductor circuit such as a pixel circuit provided under the light-emitting element from diffusing into the light-emitting element. This prevents deterioration of the light-emitting element. Furthermore, in the display device according to one embodiment of the present invention, a barrier insulating film against oxygen may be provided under the light-emitting element. This prevents deterioration of the light-emitting element due to excessive oxygen diffusing into the light-emitting element.

[0049] Furthermore, when an oxide semiconductor is provided in the semiconductor circuit, impurities such as water or hydrogen contained in the light-emitting element and the interlayer insulating film over the light-emitting element can be prevented from diffusing into the oxide semiconductor, thereby preventing deterioration in the electrical characteristics and reliability of the element including the oxide semiconductor.

[0050] As described above, according to one embodiment of the present invention, diffusion of impurities into a light-emitting element and a semiconductor circuit such as a pixel circuit can be prevented, so that a highly reliable display device can be provided.

[0051] 1B , an insulating layer 124 may be further provided to cover the light-emitting element 120. Like the insulating layer 122, the insulating layer 124 also functions as a barrier insulating film against impurities such as water or hydrogen. By providing the insulating layer 124, it is possible to prevent impurities such as water or hydrogen from diffusing from an interlayer insulating film provided on the light-emitting element 120 to the light-emitting element 120 and the semiconductor circuit of the substrate 101. Like the insulating layer 122, the insulating layer 124 may also function as a barrier insulating film against oxygen. This makes it possible to prevent excess oxygen from diffusing into the light-emitting element 120 and causing deterioration of the light-emitting element 120.

[0052] In this case, it is preferable that the insulating layer 124 be in contact with the insulating layer 122 in a region that does not overlap with the conductive layer 111. Here, the insulating layer 124 is in contact with the top surface and side surfaces of the conductive layer 116, the side surfaces of the EL layer 115, and the side surfaces of the conductive layer 111. This results in a structure in which the light-emitting element 120 is enclosed by the insulating layer 124 and the insulating layer 122, which can further suppress the diffusion of impurities such as water or hydrogen into the light-emitting element 120.

[0053] 1C , if the insulating layer 124 alone can sufficiently suppress the diffusion of impurities, a configuration may be adopted in which only the insulating layer 124 is provided without providing the insulating layer 122. In this case, the insulating layer 124 and the conductive layer 111 are provided in contact with the insulating layer 121.

[0054] In the display device 100 shown in FIGS. 1A to 1C , the EL layer 115 and the conductive layer 116 are separated between adjacent light-emitting elements of different colors. This prevents leakage current from flowing through the EL layer 115 between adjacent light-emitting elements of different colors. Therefore, light emission caused by the leakage current can be suppressed, and a high-contrast display can be achieved. Furthermore, even when the resolution is increased, a highly conductive material can be used for the EL layer 115, which allows for a wider range of material options, making it easier to improve efficiency, reduce power consumption, and improve reliability.

[0055] In the display device 100, the EL layer 115 and the conductive layer 116 are preferably processed so as to be continuous without being separated between pixels that exhibit the same color. For example, the EL layer 115 and the conductive layer 116 can be processed into a stripe shape. This allows the conductive layers 116 of all light-emitting elements to be applied with a predetermined potential without being in a floating state.

[0056] The EL layer 115 and the conductive layer 116 may be formed into island patterns by film formation using a shadow mask such as a metal mask or an FMM (fine metal mask, high-resolution metal mask). However, it is preferable to use a processing method that does not use a metal mask or an FMM. A typical example of such a processing method is photolithography. Other methods that can be used include nanoimprinting and sandblasting. In this specification and the like, a device fabricated using a metal mask or an FMM (fine metal mask, high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. In this specification and the like, a device fabricated without using a metal mask or an FMM may be referred to as a device with an MML (metal maskless) structure.

[0057] This makes it possible to form extremely fine patterns in the MML (metal maskless) structure, and therefore the definition and aperture ratio can be improved compared to the MM (metal mask) structure.

[0058] 1A to 1C , the EL layer 115 may have an edge that is substantially aligned with an edge of the conductive layer 111. Alternatively, the conductive layer 116 may have an edge that is substantially aligned with an edge of the conductive layer 111. Alternatively, the EL layer 115 may have an edge that is located outside the conductive layer 111, and the other edge that is substantially aligned with an edge of the conductive layer 111. Alternatively, the conductive layer 116 may have an edge that is located outside the conductive layer 111, and the other edge that is substantially aligned with an edge of the conductive layer 111.

[0059] The conductive layer 116 may be disposed so as not to short-circuit at least with the conductive layer 111. For example, as shown in FIG. 2A , the EL layer 115 may be disposed so that an end of the EL layer 115 is positioned outside an end of the conductive layer 111 in the cross section of the display device 100. The end of the EL layer 115 covers an end of the conductive layer 111. By positioning the end of the EL layer 115 outside the end of the conductive layer 111, it is possible to prevent a short circuit between the conductive layer 111 and the conductive layer 116. Furthermore, as shown in FIG. 2A , the conductive layer 116 may be disposed so that an end of the conductive layer 116 is positioned outside the end of the conductive layer 111 in the cross section of the display device 100.

[0060] 2B , a configuration may be adopted in which an insulator 117 is provided to cover the end portion of the conductive layer 111. The insulator 117 may also be called a bank, a partition wall, a barrier, an embankment, or the like. The insulator 117 is provided so as to expose the upper surface of the conductive layer 111. By providing the insulator 117, it is possible to suppress short-circuiting between the conductive layer 111 and the conductive layer 116.

[0061] 2A and 2B show a configuration in which insulating layers 122 and 124 are provided, similar to FIG. 1B, but the present invention is not limited to this and the same structure as that shown in FIG. 1A or 1C may also be used.

[0062] [Light-emitting element] The light-emitting element that can be used for the light-emitting element 120 can be a self-luminous element, and includes elements whose brightness is controlled by current or voltage. For example, an LED, an organic EL element, an inorganic EL element, etc. can be used. In particular, it is preferable to use an organic EL element.

[0063] The light-emitting element may be of a top emission type, a bottom emission type, a dual emission type, etc. A conductive film that transmits visible light is used for the electrode from which light is extracted. It is also preferable to use a conductive film that reflects visible light for the electrode from which light is not extracted.

[0064] In one embodiment of the present invention, it is particularly preferable to use a top-emission type light-emitting element that emits light to the side opposite to the formation surface side, or a dual-emission type light-emitting element that emits light to both the formation surface side and the side opposite to the formation surface side.

[0065] The EL layer 115 includes at least a light-emitting layer. The EL layer 115 may further include a layer containing a substance with a high hole-injection property, a substance with a high hole-transport property, a hole-blocking material, an electron-blocking material, a substance with a high electron-transport property, a substance with a high electron-injection property, or a bipolar substance (a substance with high electron-transport property and high hole-transport property), as a layer other than the light-emitting layer.

[0066] Either a low molecular weight compound or a high molecular weight compound, or an inorganic compound, can be used for the EL layer 115. The layers constituting the EL layer 115 can be formed by a method such as vapor deposition (including vacuum vapor deposition), a transfer method, a printing method, an inkjet method, or a coating method.

[0067] When a voltage higher than the threshold voltage of the light-emitting element 120 is applied between the cathode and the anode, holes are injected from the anode side and electrons are injected from the cathode side into the EL layer 115. The injected electrons and holes recombine in the EL layer 115, causing the light-emitting substance contained in the EL layer 115 to emit light.

[0068] Here, the EL layer 115 used for the light-emitting element 120B is referred to as EL layer 115B, the EL layer 115 used for the light-emitting element 120G is referred to as EL layer 115G, and the EL layer 115 used for the light-emitting element 120R is referred to as EL layer 115R. The EL layer 115B contains a light-emitting substance that emits B (blue) light. The EL layer 115G contains a light-emitting substance that emits G (green). The EL layer 115R contains a light-emitting substance that emits R (red). A structure in which different light-emitting elements are colored to emit different colors (here, blue (B), green (G), and red (R)) is sometimes referred to as an SBS (Side By Side) structure. This configuration makes it possible to provide a display device with lower power consumption than a display device with a structure in which white light-emitting elements are colored by colored layers.

[0069] The above-described light-emitting layer and the layer containing a substance with high hole-injection properties, a substance with high hole-transport properties, a substance with high electron-transport properties, a substance with high electron-injection properties, a bipolar substance, or the like may each contain an inorganic compound such as quantum dots or a polymer compound (oligomer, dendrimer, polymer, or the like). For example, quantum dots can be used in the light-emitting layer to function as a light-emitting material.

[0070] Examples of quantum dot materials that can be used include colloidal quantum dot materials, alloy quantum dot materials, core-shell quantum dot materials, and core quantum dot materials. Materials containing elements from groups 12 and 16, 13 and 15, or 14 and 16 may also be used. Alternatively, quantum dot materials containing elements such as cadmium, selenium, zinc, sulfur, phosphorus, indium, tellurium, lead, gallium, arsenic, and aluminum may also be used.

[0071] A conductive film that transmits visible light and can be used for the conductive layer 116 or the like can be formed using, for example, indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide doped with gallium, or the like. Metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, alloys containing these metal materials, or nitrides of these metal materials (e.g., titanium nitride), can also be used by forming them thin enough to have light-transmitting properties. A stacked film of the above materials can also be used as the conductive layer. For example, a stacked film of an alloy of silver and magnesium and indium tin oxide is preferable because it can increase conductivity. Graphene or the like may also be used.

[0072] The semi-transmitting and semi-reflective conductive film that can be used for the conductive layer 116 preferably has a reflectance to visible light (for example, a reflectance to light having a predetermined wavelength in the range of 400 nm to 700 nm) of 20% to 80% inclusive, preferably 40% to 70% inclusive. The reflectance to visible light of a reflective conductive film is preferably 40% to 100% inclusive, preferably 70% to 100% inclusive. The reflectance to visible light of a light-transmitting conductive film is preferably 0% to 40% inclusive, preferably 0% to 30% inclusive.

[0073] The conductive layer 111 preferably includes a conductive film that reflects visible light in a portion located on the EL layer 115 side. For example, the conductive layer 111 can be made of a metal material such as aluminum, gold, platinum, silver, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium, or an alloy containing these metal materials. Copper is preferable because it has a high reflectance to visible light. Aluminum is also preferable because it is easy to process since electrodes can be easily etched and has a high reflectance to visible light and near-infrared light. Lanthanum, neodymium, germanium, or the like may be added to the above metal material or alloy. An alloy containing titanium, nickel, or neodymium and aluminum (aluminum alloy) may also be used. An alloy containing copper, palladium, magnesium, and silver may also be used. An alloy containing silver and copper is preferable because it has high heat resistance.

[0074] The conductive layer 111 may also have a structure in which a conductive metal oxide film is stacked on a conductive film that reflects visible light. Such a structure can suppress oxidation and corrosion of the conductive film that reflects visible light. For example, stacking a metal film or a metal oxide film in contact with an aluminum film or an aluminum alloy film can suppress oxidation. Examples of materials for such metal films and metal oxide films include titanium and titanium oxide. Alternatively, the conductive film that transmits visible light and a film made of a metal material may be stacked. For example, a stacked film of silver and indium tin oxide, or a stacked film of an alloy of silver and magnesium and indium tin oxide can be used.

[0075] 3A, the conductive layer 111 may have a structure in which a conductive layer 111a is provided as a lower conductive layer, and a conductive layer 111b is provided as an upper conductive layer on the conductive layer 111a. In such a structure, a conductive film that reflects visible light is preferably used as the conductive layer 111b. The reflectance of the conductive layer 111a may be lower than that of the conductive layer 111b. A material with high conductivity may be used as the conductive layer 111a. A material with excellent processability may be used as the conductive layer 111a.

[0076] The conductive layer 111b is preferably formed using any of the materials and structures that can be used for the conductive layer 111, as described above.

[0077] The conductive layer 111a can be made of, for example, a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, yttrium, zirconium, or tantalum, an alloy containing these metal materials, or a nitride of these metal materials (e.g., titanium nitride).

[0078] When aluminum is used for the conductive layer 111 or the conductive layer 111b, the thickness is preferably 40 nm or more, more preferably 70 nm or more, to sufficiently increase the reflectance of visible light, etc. When silver is used for the conductive layer 111 or the conductive layer 111b, the thickness is preferably 70 nm or more, more preferably 100 nm or more, to sufficiently increase the reflectance of visible light, etc.

[0079] For example, tungsten can be used for the conductive layer 111a, and aluminum or an aluminum alloy can be used for the conductive layer 111b. The conductive layer 111b may have a structure in which titanium oxide is provided in contact with an upper portion of aluminum or an aluminum alloy. Alternatively, the conductive layer 111b may have a structure in which titanium is provided in contact with an upper portion of aluminum or an aluminum alloy, and titanium oxide is provided in contact with an upper portion of the titanium.

[0080] Alternatively, the conductive layers 111a and 111b may both be formed using a material and a structure selected from the materials and structures that can be used for the conductive layer 111 described above.

[0081] The conductive layer 111 may also be a stacked film of three or more layers.

[0082] Although FIG. 3A shows a configuration in which insulating layers 122 and 124 are provided, similar to FIG. 1B, the present invention is not limited to this and the same structure as that shown in FIG. 1A or 1C may be used.

[0083] Examples of materials that can be used for the plug 131 include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, gold, silver, platinum, magnesium, iron, cobalt, palladium, tantalum, and tungsten, alloys containing these metal materials, and nitrides of these metal materials. Furthermore, films containing these materials can be used as a single layer or a multilayer structure for the plug 131. For example, there are a single-layer structure of an aluminum film containing silicon, a two-layer structure of an aluminum film stacked on a titanium film, a two-layer structure of an aluminum film stacked on a tungsten film, a two-layer structure of a copper film stacked on a copper-magnesium-aluminum alloy film, a two-layer structure of a copper film stacked on a titanium film, a two-layer structure of a copper film stacked on a tungsten film, a three-layer structure of a titanium film or titanium nitride film, an aluminum film or copper film stacked on top of that, and a titanium film or titanium nitride film formed on top of that, a three-layer structure of a molybdenum film or molybdenum nitride film, an aluminum film or copper film stacked on top of that, and a molybdenum film or molybdenum nitride film formed on top of that, etc. Note that oxides such as indium oxide, tin oxide, or zinc oxide may also be used. In addition, using copper containing manganese is preferable because it improves the controllability of the shape by etching.

[0084] The electrodes constituting the light-emitting element may be formed by vapor deposition or sputtering. Alternatively, they may be formed by a discharge method such as an ink-jet method, a printing method such as a screen printing method, or a plating method.

[0085] The insulating layer 121 functions as an interlayer insulating film and preferably has a low dielectric constant. By using a material with a low dielectric constant as the interlayer film, parasitic capacitance occurring between wirings can be reduced. For example, the insulating layer 121 may be formed using silicon oxide, silicon oxynitride, silicon oxide to which fluorine has been added, silicon oxide to which carbon has been added, silicon oxide to which carbon and nitrogen have been added, silicon oxide having vacancies, or the like, as appropriate.

[0086] For example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, silicon nitride oxide, or the like can be used as the insulating layer 122. For example, the insulating layer 122 having a high ability to suppress the diffusion of impurities such as hydrogen can be formed by a silicon nitride (SiN ) film formed by a sputtering method, an ALD method, or the like. ｘ (where x is any number greater than 0) is preferably used. In this case, the insulating layer 122 is an insulator containing at least nitrogen and silicon.

[0087] The insulating layer 122 having a high ability to capture or fix impurities such as hydrogen may be, for example, an aluminum oxide (AlO ｘ : x is any number greater than 0), or hafnium oxide (HfO ｙ It is preferable to use a metal oxide such as aluminum oxide (where y is an arbitrary number greater than 0). When aluminum oxide is used for the insulating layer 122, the insulating layer 122 becomes an insulator containing at least oxygen and aluminum. It is also preferable to use an oxide having an amorphous structure for the insulating layer 122. In such a metal oxide having an amorphous structure, oxygen atoms have dangling bonds, and the dangling bonds may have the property of capturing or fixing hydrogen. By using such a metal oxide having an amorphous structure, hydrogen can be captured or fixed. It is particularly preferable to capture or fix hydrogen contained in the insulating layer 121.

[0088] The insulating layer 122 preferably has an amorphous structure, but may have a crystalline region formed in part. Alternatively, the insulating layer 122 may have a multilayer structure in which an amorphous layer and a layer having a crystalline region are stacked. For example, the insulating layer 122 may have a stacked structure in which a layer having a crystalline region, typically a layer having a polycrystalline structure, is formed on an amorphous layer.

[0089] The insulating layer 122 may have a stacked structure. For example, in the case of a two-layer structure, an aluminum oxide film or a hafnium oxide film can be provided over a silicon nitride film.

[0090] The insulating layer 124 may also be formed using the insulating material that can be used for the insulating layer 122. The insulating layer 124 may also have a stacked structure. For example, in the case of a two-layer structure, an aluminum oxide film or a silicon nitride film formed by a sputtering method may be provided on an aluminum oxide film formed by an ALD method. In addition, in the case of a three-layer structure, for example, an aluminum oxide film formed by a sputtering method may be provided on an aluminum oxide film formed by an ALD method, and a silicon nitride film formed by a sputtering method may be provided on the aluminum oxide film formed by an ALD method.

[0091] The insulating layer 124 preferably includes an aluminum oxide film formed by an ALD method. By forming the insulating layer 124 by an ALD method, the insulating layer 124 can be formed with good coverage over steps formed by the conductive layer 111, the EL layer 115, and the conductive layer 116. This can prevent impurities such as water from entering the light-emitting element 120 from above.

[0092] 1B, it is preferable to use silicon nitride films for the insulating layers 122 and 124, and further provide an aluminum oxide film inside the silicon nitride films, so that hydrogen remaining in the region sealed with the silicon nitride films can be captured or fixed by the aluminum oxide film.

[0093] Furthermore, in the structure shown in FIG. 1B and other figures, the insulating layer 122 is in contact with the conductive layer 111 and the insulating layer 124, but the present invention is not limited to this. For example, as shown in FIG. 3B , a configuration may be adopted in which an insulating layer 125 is provided between the insulating layer 122 and the conductive layer 111 and the insulating layer 124. The insulating layer 125 may be made of an insulating material that can be used for the insulating layer 121. In this case, a recess may be formed in the surface of the insulating layer 125 where the conductive layer 111 is not provided. For example, the recess may be formed by etching the insulating layer 125 during an etching step when forming the conductive layer 111.

[0094] As shown in FIG. 4A , a white-emitting light-emitting substance may be used as the EL layer 115 of the light-emitting element 120. In this case, a colored layer overlapping the light-emitting element 120 may be provided, as described later. When a white-emitting light-emitting substance is used as the EL layer 115, the EL layer 115 preferably contains two or more types of light-emitting substances. For example, white light emission can be obtained by selecting light-emitting substances such that the respective emissions of the two or more light-emitting substances have a complementary color relationship. For example, it is preferable to include two or more light-emitting substances that emit light of R (red), G (green), B (blue), Y (yellow), O (orange), etc., or light-emitting substances that emit light containing two or more spectral components of R, G, and B. It is also preferable to use a light-emitting element whose emission spectrum has two or more peaks in the wavelength range of the visible light region (e.g., 350 nm to 750 nm). It is also preferable that the emission spectrum of a material having a peak in the yellow wavelength region also contains spectral components in the green and red wavelength regions.

[0095] The EL layer 115 may have a stacked configuration in which an emitting layer containing a emitting material that emits one color and an emitting layer containing a emitting material that emits another color are stacked. For example, the multiple emitting layers in the EL layer 115 may be stacked in contact with each other, or may be stacked via a region that does not contain any emitting material. For example, a configuration in which a region that contains the same material (e.g., host material, assist material) as the fluorescent or phosphorescent emitting layer but does not contain any emitting material may be provided between the fluorescent or phosphorescent emitting layer. This facilitates fabrication of the light-emitting element and reduces the driving voltage.

[0096] The light emitting element 120 may be a single element having one EL layer, or may be a tandem element in which a plurality of EL layers are stacked with a charge generating layer interposed therebetween.

[0097] As shown in Fig. 4A , the EL layer 115 may be provided in common to all the light-emitting elements 120. In Fig. 4A , a continuous EL layer 115 is provided so as to cover the conductive layer 111 of each light-emitting element 120. Also, as shown in Fig. 4A , the conductive layer 116 may be provided in common to the light-emitting elements 120R, 120G, and 120B. The conductive layer 116 functions as, for example, an electrode to which a common potential is applied. By providing the conductive layer in common, the number of steps for manufacturing the light-emitting elements 120 can be reduced, which is preferable.

[0098] In the light-emitting element 120, a conductive layer 114 may be provided between the conductive layer 111 and the EL layer 115. The conductive layer 114 has a function of transmitting visible light.

[0099] The conductive layer 114 can be formed using the above-described conductive film that is transparent to visible light. Alternatively, the conductive layer 114 can be formed using a thin conductive film that reflects visible light and is thin enough to transmit visible light. By using a stacked structure of the conductive film and the above-described conductive film that transmits visible light, the conductivity and mechanical strength can be increased.

[0100] 4B , the conductive layer 114 is disposed between the conductive layer 111 and the EL layer 115. The conductive layer 114 is located on the conductive layer 111. Here, the EL layer 115 is preferably provided so as to cover the edge of the conductive layer 114.

[0101] 4B , the conductive layer 114 provided in each light-emitting element 120 preferably has a different thickness for each light-emitting element. Of the three conductive layers 114, conductive layer 114B is the thinnest, and conductive layer 114R is the thickest. Here, the distance between the upper surface of conductive layer 111 and the lower surface of conductive layer 116 (i.e., the interface between conductive layer 116 and EL layer 115) in each light-emitting element is the largest in light-emitting element 120R and the smallest in light-emitting element 120B. By changing the distance between the upper surface of conductive layer 111 and the lower surface of conductive layer 116 in each light-emitting element, the optical distance (optical path length) in each light-emitting element can be changed.

[0102] Of the three light-emitting elements, light-emitting element 120R has the longest optical path length and therefore emits light R, in which light with the longest wavelength is intensified. On the other hand, light-emitting element 120B has the shortest optical path length and therefore emits light B, in which light with the shortest wavelength is intensified. Light-emitting element 120G emits light G, in which light with an intermediate wavelength is intensified. For example, light R can be light in which red light is intensified, light G can be light in which green light is intensified, and light B can be light in which blue light is intensified.

[0103] With this configuration, it is not necessary to create separate EL layers for the light-emitting elements 120 for different colors, and color display with high color reproducibility can be achieved using elements with the same configuration. Also, it becomes possible to arrange the light-emitting elements 120 at an extremely high density. For example, a display device with a resolution of more than 5000 ppi can be realized.

[0104] In each light-emitting element, it is preferable that the optical distance between the surface of the conductive layer 111 that reflects visible light and the conductive layer 116 that is semi-transparent and semi-reflective to visible light is adjusted to be mλ / 2 (m is a natural number, but is not 0) or close to it, where λ is the wavelength of light whose intensity is to be increased.

[0105] It should be noted that the optical distance described above is difficult to precisely adjust because it is related to the product of the physical distance between the reflective surface of the conductive layer 111 and the reflective surface of the semi-transmissive and semi-reflective conductive layer 116 and the refractive index of the layer provided therebetween. Therefore, it is preferable to adjust the optical distance by assuming that the surface of the conductive layer 111 and the surface of the semi-transmissive and semi-reflective conductive layer 116 are each a reflective surface.

[0106] Furthermore, as will be described later, by providing a colored layer overlapping the light emitting element 120, the color purity of the light emitted from the light emitting element can be improved.

[0107] The light-emitting element 120 may have a stacked structure of multiple EL layers. For example, the EL layer 115 may have a stacked structure of an EL layer 115B containing a light-emitting substance that emits blue light, an EL layer 115G containing a light-emitting substance that emits green light, and an EL layer 115R containing a light-emitting substance that emits red light. Each EL layer may have an electron injection layer, an electron transport layer, a charge generation layer, a hole transport layer, a hole injection layer, and the like, in addition to a layer containing a light-emitting compound. A charge generation layer may be provided between the EL layer 115B and the EL layer 115G. Alternatively, a charge generation layer may be provided between the EL layer 115G and the EL layer 115R.

[0108] 16A , the EL layer 115 included in the light-emitting element 120 can be composed of a plurality of layers, such as a layer 4420, a light-emitting layer 4411, and a layer 4430. The layer 4420 can have, for example, a layer containing a substance with high electron-injection properties (electron-injection layer) and a layer containing a substance with high electron-transport properties (electron-transport layer). The light-emitting layer 4411 contains, for example, a light-emitting compound. The layer 4430 can have, for example, a layer containing a substance with high hole-injection properties (hole-injection layer) and a layer containing a substance with high hole-transport properties (hole-transport layer).

[0109] A structure having the layer 4420, the light-emitting layer 4411, and the layer 4430 provided between a pair of electrodes can function as a single light-emitting unit, and the structure of FIG. 16A is referred to as a single structure in this specification.

[0110] Note that a configuration in which a plurality of light-emitting layers (light-emitting layers 4411, 4412, and 4413) are provided between the layer 4420 and the layer 4430 as shown in FIG. 16B is also a variation of the single structure.

[0111] 16C , a configuration in which a plurality of light-emitting units (EL layers 115 a, 115 b) are connected in series via an intermediate layer (charge generating layer) 4440 is referred to as a tandem structure in this specification. Note that although the configuration shown in FIG. 16C is referred to as a tandem structure in this specification and the like, this is not limiting, and for example, the tandem structure may also be referred to as a stack structure. Note that by using a tandem structure, a light-emitting element capable of emitting light with high brightness can be obtained.

[0112] The light-emitting element can emit light of red, green, blue, cyan, magenta, yellow, white, or the like, depending on the material of the EL layer 115. Furthermore, the color purity can be further improved by providing the light-emitting element with a microcavity structure.

[0113] A light-emitting element that emits white light preferably has a structure in which two or more kinds of light-emitting substances are contained in the light-emitting layer. To obtain white light emission, light-emitting substances may be selected such that the respective emissions of the two or more light-emitting substances are in a complementary color relationship.

[0114] The light-emitting layer preferably contains two or more light-emitting materials that emit light of R (red), G (green), B (blue), Y (yellow), O (orange), etc. Alternatively, it is preferable that the light-emitting layer contains two or more light-emitting materials, and the light emitted by each of the light-emitting materials contains spectral components of two or more colors of R, G, and B.

[0115] [Manufacturing Method Example] An example of a manufacturing method of a display device according to one embodiment of the present invention will be described with reference to the drawings.

[0116] Thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum evaporation method, a pulsed laser deposition (PLD) method, an atomic layer deposition (ALD) method, etc. CVD methods include a plasma enhanced chemical vapor deposition (PECVD) method and a thermal CVD method. One type of thermal CVD method is a metal organic chemical vapor deposition (MOCVD) method.

[0117] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed by methods such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating, and knife coating.

[0118] Furthermore, when processing the thin film that constitutes the display device, it can be processed using a photolithography method or the like. Alternatively, the thin film may be processed using a nanoimprint method, a sandblasting method, a lift-off method or the like. Furthermore, the island-shaped thin film may be directly formed by a film formation method using a shielding mask such as a metal mask.

[0119] There are two typical photolithography methods: one is to form a resist mask on the thin film to be processed, process the thin film by etching or the like, and then remove the resist mask; the other is to form a photosensitive thin film, and then process the thin film into the desired shape by exposure and development.

[0120] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or light obtained by mixing these. In addition, ultraviolet light, KrF laser light, ArF laser light, etc. can also be used. Further, exposure may be performed by immersion lithography technology. Also, as the light used for exposure, extreme ultraviolet (EUV: Extreme Ultra-violet) light or X-rays may be used. Instead of the light used for exposure, an electron beam can also be used. Using extreme ultraviolet light, X-rays or an electron beam is preferable because extremely fine processing becomes possible. When performing exposure by scanning a beam such as an electron beam, a photomask may not be used.

[0121] For etching of the thin film, a dry etching method, a wet etching method, a sandblasting method, etc. can be used.

[0122] An example of the method for manufacturing the display device shown in FIG. 1B will be described using FIGS. 5A to 5E and FIGS. SA to 6D. By using the manufacturing method shown in FIGS. 5A to 5E and FIGS. 6A to 6D, the EL layer 115 and the conductive layer 116 can be processed without using a metal mask.

[0123] 〔Preparation of Substrate 101〕 As the substrate 101, a substrate having heat resistance sufficient to withstand at least subsequent heat treatment can be used. When an insulating substrate is used as the substrate 101, examples include a glass substrate, a quartz substrate, a sapphire substrate, and a ceramics substrate. In addition, a single crystal semiconductor substrate, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, and a semiconductor substrate such as an SOI substrate made of silicon or silicon carbide can be used.

[0124] In particular, it is preferable to use, as the substrate 101, a substrate on which a semiconductor circuit including a semiconductor element such as a transistor is formed over the semiconductor substrate or an insulating substrate. Such a semiconductor element may be formed using a semiconductor substrate such as a single crystal silicon substrate, or an oxide semiconductor film. The semiconductor circuit preferably constitutes, for example, a pixel circuit, a gate line driver circuit (gate driver), a source line driver circuit (source driver), or the like. In addition to the above, an arithmetic circuit, a memory circuit, or the like may also be formed.

[0125] In this embodiment, a substrate on which at least pixel circuits are formed is used as the substrate 101 .

[0126] [Deposition of insulating layers 121 and 122] An insulating film to be the insulating layer 121 is deposited on the substrate 101. Next, an insulating film to be the insulating layer 122 is deposited on the insulating layer 121 (see FIG. 5A). The insulating layers 121 and 122 can be formed appropriately using the insulating materials and deposition methods described above.

[0127] Here, by using a material with a low etching rate for the insulating layer 122, the insulating layer 122 can function as an etching stopper when the conductive layer 111, the EL layer 115, and the conductive layer 116 are formed.

[0128] 1C , a configuration without the insulating layer 122 is also possible. In this case, the insulating layer 121 can be made of a material with a high etching rate. This allows relatively easy formation of an opening for embedding the plug 131 in a later step. Furthermore, in a step of forming the conductive layer 111 described later, a recess may be formed in a region of the insulating layer 121 that does not overlap with the conductive layer 111.

[0129] [Formation of Plug 131] Openings are formed in the insulating layers 121 and 122 at positions where the plugs 131 are to be formed, reaching the substrate 101. The openings preferably reach electrodes or wiring provided on the substrate 101. Subsequently, a conductive film is formed to fill the openings, and then a planarization process is performed to expose the top surface of the insulating layer 122. This allows the plugs 131 to be formed embedded in the insulating layers 121 and 122 (see FIG. 5B ).

[0130] [Formation of Conductive Layer 111] A conductive film is formed on the insulating layer 122 and the plug 131. The conductive film is processed into an island shape to form the conductive layer 111 (see FIG. 5C). The conductive layer 111 is electrically connected to the plug 131.

[0131] [Formation of EL Layer 115 and Conductive Layer 116] Next, the EL layer 115Bf and conductive layer 116f of the light-emitting element 120B are formed in this order on the conductive layer 111 and the insulating layer 122. Next, a pattern is formed on the conductive layer 116f using resist RES1 (see FIG. 5D ). Here, the EL layer 115Bf is a layer that will become the EL layer 115B in a later process. The conductive layer 116f is a layer that will become the conductive layer 116 in a later process. The EL layer 115Bf, EL layer 115Gf (described later), and EL layer 115Rf may be collectively referred to as the EL layer 115f.

[0132] The EL layer 115f includes at least a layer containing a light-emitting compound. Alternatively, the EL layer 115f may include a stack of an electron injection layer, an electron transport layer, a charge generation layer, a hole transport layer, and a hole injection layer. The EL layer 115f can be formed by a liquid phase method such as a vapor deposition method or an inkjet method.

[0133] The conductive layer 116f is formed to be transmissive and reflective to visible light. For example, a metal film or alloy film thin enough to transmit visible light can be used. Alternatively, a light-transmitting conductive film (for example, a metal oxide film) may be stacked on such a film.

[0134] Subsequently, etching is performed using the resist RES1 as a mask to form the conductive layer 116 and the EL layer 115B in this order, and then the resist RES1 is removed (see FIG. 5E).

[0135] Next, the EL layer 115Gf and the conductive layer 116f of the light-emitting element 120G are formed in this order on the conductive layer 111, the insulating layer 122, and the conductive layer 116 of the light-emitting element 120B. Next, a pattern is formed on the conductive layer 116f using a resist RES2 (see FIG. 6A). Here, the EL layer 115Gf is a layer that will become the EL layer 115G in a later process.

[0136] Subsequently, etching is performed using the resist RES2 as a mask to form the conductive layer 116 and the EL layer 115G in this order, and then the resist RES2 is removed.

[0137] Next, the EL layer 115Rf and conductive layer 116f of the light-emitting element 120R are formed in this order on the conductive layer 111, the insulating layer 122, the conductive layer 116 of the light-emitting element 120B, and the conductive layer 116 of the light-emitting element 120G. Next, a pattern is formed on the conductive layer 116f using a resist RES3 (see FIG. 6B ). Here, the EL layer 115Rf is a layer that will become the EL layer 115R in a later process.

[0138] Subsequently, etching is performed using the resist RES3 as a mask to form the conductive layer 116 and the EL layer 115R in this order, and then the resist RES3 is removed (see FIG. 6C).

[0139] Note that in this embodiment, the EL layer 115 and the conductive layer 116 are formed after the conductive layer 111 is formed, but the present invention is not limited to this. For example, the conductive layer 111, the EL layer 115f, and the conductive layer 116f can be formed in this order and processed into an island shape all at once to form the conductive layer 111, the EL layer 115, and the conductive layer 116.

[0140] [Deposition of Insulating Layer 124] Next, an insulating film to be the insulating layer 124 is deposited on the insulating layer 122 and the conductive layer 116 (see FIG. 6D). The insulating layer 124 can be formed appropriately using the insulating material and deposition method described above. Note that the deposition temperature of the insulating layer 124 is preferably set within a range in which the EL layer 115 does not deteriorate. Alternatively, as shown in FIG. 1A, a configuration without the insulating layer 124 may be used.

[0141] In this manner, the display device 100 having the light emitting elements 120R, 120G, and 120B can be formed.

[0142] [Configuration Example 2] An example of a display device including a transistor will be described below.

[0143] Configuration Example 2-1 FIG. 7 is a schematic cross-sectional view of a display device 200A.

[0144] The display device 200A includes a substrate 201, a light emitting element 120R, a light emitting element 120G, a light emitting element 120B, a capacitor element 240, a transistor 210, and the like.

[0145] The laminated structure from the substrate 201 to the capacitor element 240 corresponds to the substrate 101 in the first configuration example.

[0146] The transistor 210 is a transistor in which a channel formation region is formed in a substrate 201. The substrate 201 can be, for example, a semiconductor substrate such as a single crystal silicon substrate. The transistor 210 includes a part of the substrate 201, a conductive layer 211, a low-resistance region 212, an insulating layer 213, an insulating layer 214, and the like. The conductive layer 211 functions as a gate electrode. The insulating layer 213 is located between the substrate 201 and the conductive layer 211 and functions as a gate insulating layer. The low-resistance region 212 is a region in which the substrate 201 is doped with impurities and functions as one of a source and a drain. The insulating layer 214 is provided to cover a side surface of the conductive layer 211 and functions as an insulating layer.

[0147] Furthermore, an element isolation layer 215 is provided between two adjacent transistors 210 so as to be buried in the substrate 201 .

[0148] In addition, an insulating layer 261 is provided to cover the transistor 210 , and a capacitor 240 is provided over the insulating layer 261 .

[0149] The capacitor 240 includes a conductive layer 241, a conductive layer 242, and an insulating layer 243 located therebetween. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 242 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as a dielectric of the capacitor 240.

[0150] The conductive layer 241 is provided over the insulating layer 261 and is electrically connected to one of the source and drain of the transistor 210 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 242 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0151] An insulating layer 121 is provided to cover the capacitor element 240, an insulating layer 122 is provided on the insulating layer 121, and the light-emitting elements 120R, 120G, 120B, etc. are provided on the insulating layer 121. Here, an example is shown in which the configuration illustrated in FIG. 1B is used as the configuration of the light-emitting element 120R, the light-emitting element 120G, the light-emitting element 120B, etc., but the present invention is not limited to this, and various configurations exemplified above can be applied.

[0152] In the display device 200A, an insulating layer 124, an insulating layer 162, and an insulating layer 163 are provided in this order to cover the conductive layer 116 of the light-emitting element 120. These three insulating layers function as protective layers that prevent impurities such as water from diffusing into the light-emitting element 120. The insulating layer 163 is preferably made of an inorganic insulating film with low moisture permeability, such as a silicon oxide film, a silicon nitride film, or an aluminum oxide film. The insulating layer 162 can be made of an organic insulating film with high light transmissivity. Using an organic insulating film for the insulating layer 162 reduces the influence of unevenness below the insulating layer 162, making it possible to smooth the surface on which the insulating layer 163 is formed. This reduces the likelihood of defects such as pinholes occurring in the insulating layer 163, thereby further improving the moisture permeability of the protective layer. The configuration of the protective layer covering the light-emitting element 120 is not limited to this, and it may be a single-layer structure, a two-layer structure, or a stacked structure of four or more layers.

[0153] By providing the insulating layers 122 and 124, impurities such as water or hydrogen can be prevented from diffusing into the light-emitting element 120, as described in the above embodiment.

[0154] On the insulating layer 163, a coloring layer 165R overlapping the light-emitting element 120R, a coloring layer 165G overlapping the light-emitting element 120G, and a coloring layer 165B overlapping the light-emitting element 120B are provided. For example, the coloring layer 165R transmits red light, the coloring layer 165G transmits green light, and the coloring layer 165B transmits blue light. This increases the color purity of the light from each light-emitting element, resulting in a display device with higher display quality. Furthermore, by forming each coloring layer on the insulating layer 163, it is easier to align each light-emitting unit with each coloring layer than when the coloring layers are formed on the substrate 202 (described later), resulting in a display device with extremely high resolution. Note that the coloring layers 165R, 165G, and 165B may be omitted.

[0155] The display device 200A has a substrate 202 on the viewing side. The substrate 202 and the substrate 201 are bonded together by a light-transmitting adhesive layer 164. The substrate 202 can be a light-transmitting substrate such as a glass substrate, a quartz substrate, a sapphire substrate, or a plastic substrate.

[0156] With this configuration, a display device with extremely high definition and high display quality can be realized.

[0157] [Configuration Example 2-2] Fig. 8 is a schematic cross-sectional view of a display device 200B. The display device 200B differs from the display device 200A described above mainly in that the transistor configuration is different.

[0158] The transistor 220 is a transistor in which a metal oxide (also referred to as an oxide semiconductor) is used for a semiconductor layer in which a channel is formed.

[0159] The transistor 220 includes a semiconductor layer 221, an insulating layer 223, a conductive layer 224, a pair of conductive layers 225, an insulating layer 226, a conductive layer 227, and the like.

[0160] The substrate 201 over which the transistor 220 is provided can be the insulating substrate or semiconductor substrate described above.

[0161] An insulating layer 232 is provided over the substrate 201. The insulating layer 232 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 201 to the transistor 220 and prevents oxygen from being released from the semiconductor layer 221 toward the insulating layer 232. As the insulating layer 232, for example, a film through which hydrogen or oxygen is less likely to diffuse than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film, can be used.

[0162] A conductive layer 227 is provided over the insulating layer 232, and an insulating layer 226 is provided to cover the conductive layer 227. The conductive layer 227 functions as a first gate electrode of the transistor 220, and part of the insulating layer 226 functions as a first gate insulating layer. An oxide insulating film such as a silicon oxide film is preferably used for at least a portion of the insulating layer 226 that is in contact with the semiconductor layer 221. The top surface of the insulating layer 226 is preferably planarized.

[0163] The semiconductor layer 221 is provided over the insulating layer 226. The semiconductor layer 221 preferably includes a metal oxide (also referred to as an oxide semiconductor) film having semiconductor characteristics. Materials that can be suitably used for the semiconductor layer 221 will be described in detail later.

[0164] The pair of conductive layers 225 is provided over and in contact with the semiconductor layer 221 and functions as a source electrode and a drain electrode.

[0165] An insulating layer 228 is provided to cover top surfaces and side surfaces of the pair of conductive layers 225 and side surfaces of the semiconductor layer 221, and an insulating layer 261b is provided over the insulating layer 228. The insulating layer 228 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 261b or the like to the semiconductor layer 221 and prevents oxygen from being released from the semiconductor layer 221. The insulating layer 228 can be an insulating film similar to the insulating layer 232.

[0166] An opening reaching the semiconductor layer 221 is provided in the insulating layer 228 and the insulating layer 261b. An insulating layer 223 and a conductive layer 224 are buried in the opening and are in contact with side surfaces of the insulating layer 261b, the insulating layer 228, and the conductive layer 225 and an upper surface of the semiconductor layer 221. The conductive layer 224 functions as a second gate electrode, and the insulating layer 223 functions as a second gate insulating layer.

[0167] The upper surfaces of the conductive layer 224, the insulating layer 223, and the insulating layer 261b are planarized so that their heights are approximately the same, and insulating layers 229 and 261a are provided to cover them.

[0168] The insulating layer 261a and the insulating layer 261b function as interlayer insulating layers. The insulating layer 229 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 261a or the like to the transistor 220. The insulating layer 229 can be formed using an insulating film similar to the insulating layer 228 and the insulating layer 232.

[0169] A plug 271 electrically connected to one of the pair of conductive layers 225 is provided to be embedded in the insulating layer 261a, the insulating layer 229, and the insulating layer 261b. Here, the plug 271 preferably includes a conductive layer 271a covering the side surfaces of the openings of the insulating layer 261a, the insulating layer 261b, the insulating layer 229, and the insulating layer 228 and a part of the top surface of the conductive layer 225, and a conductive layer 271b in contact with the top surface of the conductive layer 271a. In this case, the conductive layer 271a is preferably made of a conductive material through which hydrogen and oxygen do not easily diffuse.

[0170] Furthermore, by providing the insulating layer 122 or the insulating layer 124, as described in the above embodiment, diffusion of impurities such as water or hydrogen into the transistor 220 can be suppressed, thereby improving the electrical characteristics and reliability of the transistor 220.

[0171] 9 is a schematic cross-sectional view of a display device 200C. The display device 200C has a stacked structure of a transistor 210 having a channel formed in a substrate 201 and a transistor 220 having a semiconductor layer including a metal oxide and having a channel formed therein.

[0172] An insulating layer 261 is provided to cover the transistor 210, and a conductive layer 251 is provided over the insulating layer 261. An insulating layer 262 is provided to cover the conductive layer 251, and a conductive layer 252 is provided over the insulating layer 262. The conductive layers 251 and 252 each function as wirings. Insulating layers 263 and 232 are provided to cover the conductive layer 252, and the transistor 220 is provided over the insulating layer 232. An insulating layer 265 is provided to cover the transistor 220, and a capacitor 240 is provided over the insulating layer 265. The capacitor 240 and the transistor 220 are electrically connected to each other by a plug 274.

[0173] The transistor 220 can be used as a transistor that forms a pixel circuit. The transistor 210 can be used as a transistor that forms a pixel circuit or a driver circuit (gate line driver circuit, source line driver circuit) for driving the pixel circuit. The transistors 210 and 220 can be used as transistors that form various circuits such as an arithmetic circuit or a memory circuit.

[0174] By using this configuration, not only pixel circuits but also driving circuits etc. can be formed directly below the light-emitting units, making it possible to make the display device smaller than when driving circuits are provided around the periphery of the display area.

[0175] 10 is a schematic cross-sectional view of a display device 200D. The display device 200D differs from the display device 200C described above mainly in that two transistors using an oxide semiconductor are stacked.

[0176] The display device 200D includes a transistor 230 between the transistor 210 and the transistor 220. The transistor 230 has a similar structure to the transistor 220 except that the transistor 230 does not include a first gate electrode. Note that the transistor 230 may include a first gate electrode.

[0177] An insulating layer 263 and an insulating layer 231 are provided to cover the conductive layer 252, and a transistor 230 is provided over the insulating layer 231. The transistor 230 and the conductive layer 252 are electrically connected to each other through a plug 273, the conductive layer 253, and a plug 272. Furthermore, an insulating layer 264 and an insulating layer 232 are provided to cover the conductive layer 253, and a transistor 220 is provided over the insulating layer 232.

[0178] For example, the transistor 220 functions as a transistor for controlling a current flowing through the light-emitting element 120. The transistor 230 functions as a selection transistor for controlling the selection state of the pixel. The transistor 210 functions as a transistor that constitutes a driver circuit for driving the pixel.

[0179] In this way, by stacking three or more layers in which transistors are formed, the area occupied by a pixel can be further reduced, and a high-definition display device can be realized.

[0180] Components such as transistors that can be applied to a display device will be described below.

[0181] [Transistor] A transistor includes a conductive layer functioning as a gate electrode, a semiconductor layer, a conductive layer functioning as a source electrode, a conductive layer functioning as a drain electrode, and an insulating layer functioning as a gate insulating layer.

[0182] Note that the structure of a transistor included in a display device of one embodiment of the present invention is not particularly limited. For example, a planar transistor, a staggered transistor, or an inverted staggered transistor may be used. Furthermore, a top-gate or bottom-gate transistor structure may be used. Alternatively, gate electrodes may be provided above and below a channel.

[0183] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0184] In the following, a transistor using a metal oxide film as a semiconductor layer in which a channel is formed will be described in particular.

[0185] As a semiconductor material for a transistor, a metal oxide having an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more can be used, typically a metal oxide containing indium, such as CAC-OS described later.

[0186] A transistor using a metal oxide, which has a wider band gap and a lower carrier density than silicon, can hold charge accumulated in a capacitor connected in series with the transistor for a long period of time due to its low off-state current.

[0187] The semiconductor layer can be, for example, a film represented by an In-M-Zn-based oxide containing indium, zinc, and M (M is a metal such as aluminum, titanium, gallium, germanium, yttrium, zirconium, lanthanum, cerium, tin, neodymium, or hafnium).

[0188] When the metal oxide constituting the semiconductor layer is an In-M-Zn-based oxide, the atomic ratio of the metal elements in the sputtering target used to deposit the In-M-Zn oxide preferably satisfies In≧M and Zn≧M. The atomic ratio of the metal elements in such a sputtering target is preferably In:M:Zn=1:1:1, In:M:Zn=1:1:1.2, In:M:Zn=3:1:2, In:M:Zn=4:2:3, In:M:Zn=4:2:4.1, In:M:Zn=5:1:6, In:M:Zn=5:1:7, In:M:Zn=5:1:8, etc. The atomic ratio of the semiconductor layer to be deposited varies within ±40% of the atomic ratio of the metal elements contained in the sputtering target.

[0189] The semiconductor layer is a metal oxide film having a low carrier density. For example, the semiconductor layer is a metal oxide film having a carrier density of 1×10 １７ / cm ３ Below 1 × 10, preferably １５ / cm ３ More preferably, 1×10 １３ / cm ３ or less, more preferably 1 × 10 １１ / cm ３ More preferably, 1×10 １０ / cm ３ is less than 1×10 −９ / cm ３ Metal oxides with carrier densities above this level can be used. Such metal oxides are called high-purity intrinsic or substantially high-purity intrinsic metal oxides. These metal oxides have a low density of defect states and stable properties.

[0190] Note that an oxide semiconductor having an appropriate composition may be used depending on the semiconductor characteristics and electrical characteristics (field-effect mobility, threshold voltage, etc.) of the transistor that are required. In order to obtain the semiconductor characteristics of the transistor that are required, it is preferable to set the carrier density, impurity concentration, defect density, atomic ratio of metal element to oxygen, interatomic distance, density, and the like of the semiconductor layer to be appropriate.

[0191] When silicon or carbon, which is one of the Group 14 elements, is contained in the metal oxide constituting the semiconductor layer, oxygen vacancies increase in the semiconductor layer, causing it to become n-type. Therefore, the concentration of silicon or carbon in the semiconductor layer (concentration obtained by secondary ion mass spectrometry) is set to 2×10 １８ atoms / cm ３ Below 2 × 10, preferably １７ atoms / cm ３ The following applies.

[0192] In addition, when an alkali metal or alkaline earth metal is bonded to a metal oxide, carriers may be generated, which may increase the off-state current of a transistor. Therefore, the concentration of an alkali metal or alkaline earth metal in a semiconductor layer obtained by secondary ion mass spectrometry is set to 1×10 １８ atoms / cm ３ Below 2 × 10, preferably １６ atoms / cm ３ Do the following:

[0193] Furthermore, if nitrogen is contained in the metal oxide constituting the semiconductor layer, electrons as carriers are generated, the carrier density increases, and the transistor is likely to become n-type. As a result, a transistor using a metal oxide containing nitrogen is likely to have normally-on characteristics. Therefore, the nitrogen concentration in the semiconductor layer obtained by secondary ion mass spectrometry is 5×10 １８ atoms / cm ３ It is preferable to do the following:

[0194] Furthermore, hydrogen contained in an oxide semiconductor may react with oxygen bonded to a metal atom to form water, thereby forming an oxygen vacancy. When hydrogen enters the oxygen vacancy, electrons serving as carriers may be generated. Furthermore, some of the hydrogen may bond with oxygen bonded to a metal atom to generate electrons serving as carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. Therefore, it is preferable to reduce the amount of hydrogen in the channel formation region of the oxide semiconductor as much as possible. Specifically, the hydrogen concentration in the channel formation region of the oxide semiconductor measured by secondary ion mass spectrometry is 1×10 ２０atoms / cm ３ Less than 5×10 １９ atoms / cm ３ less than 1×10 １９ atoms / cm ３ less than 5×10 １８ atoms / cm ３ less than 1×10 １８ atoms / cm ３ Make it less than.

[0195] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics and reliability can be obtained.

[0196] Oxide semiconductors are classified into single-crystal oxide semiconductors and non-single-crystal oxide semiconductors, and examples of non-single-crystal oxide semiconductors include c-axis-aligned crystalline oxide semiconductor (CAAC-OS), polycrystalline oxide semiconductors, nanocrystalline oxide semiconductors (nc-OS), amorphous-like oxide semiconductors (a-like OS), and amorphous oxide semiconductors.

[0197] Further, a semiconductor layer of the transistor disclosed in one embodiment of the present invention may be formed using a cloud-aligned composite oxide semiconductor (CAC-OS).

[0198] Note that the semiconductor layer of the transistor disclosed in one embodiment of the present invention can preferably be formed using the above-described non-single-crystal oxide semiconductor. As the non-single-crystal oxide semiconductor, an nc-OS or a CAAC-OS can preferably be used.

[0199] In one embodiment of the present invention, a CAC-OS is preferably used for a semiconductor layer of a transistor, because the use of a CAC-OS can impart excellent electrical characteristics or high reliability to the transistor.

[0200] The semiconductor layer may be a mixed film including two or more of a CAAC-OS region, a polycrystalline oxide semiconductor region, an nc-OS region, a pseudo-amorphous oxide semiconductor region, and an amorphous oxide semiconductor region. The mixed film may have a single-layer structure or a stacked-layer structure including two or more of the above-described regions, for example.

[0201] <Structure of CAC-OS> The structure of a CAC-OS that can be used for a transistor disclosed in one embodiment of the present invention is described below.

[0202] CAC-OS is a material in which, for example, elements constituting a metal oxide are unevenly distributed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 2 nm, or in the vicinity thereof. Note that, hereinafter, a state in which one or more metal elements are unevenly distributed in a metal oxide and regions containing the metal elements are mixed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 2 nm, or in the vicinity thereof, is also referred to as a mosaic or patch state.

[0203] The metal oxide preferably contains at least indium, particularly indium and zinc, and may further contain one or more elements selected from aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, and the like.

[0204] For example, CAC-OS in In—Ga—Zn oxide (In—Ga—Zn oxide among CAC-OS may be particularly referred to as CAC-IGZO) is an indium oxide (hereinafter, InO Ｘ１ (X1 is a real number greater than 0).) or indium zinc oxide (hereinafter referred to as In Ｘ２ Zn Ｙ２ O Ｚ２ (X2, Y2, and Z2 are real numbers greater than 0) and gallium oxide (hereinafter referred to as GaO Ｘ３(X3 is a real number greater than 0).) or gallium zinc oxide (hereinafter referred to as Ga Ｘ４ Zn Ｙ４ O Ｚ４ (X4, Y4, and Z4 are real numbers greater than 0).) The material is separated into a mosaic shape, and the mosaic InO Ｘ１ , or In Ｘ２ Zn Ｙ２ O Ｚ２ However, the structure is such that the particles are uniformly distributed in the film (hereinafter also referred to as a cloud-like structure).

[0205] That is, CAC-OS is Ｘ３ The region where In is the main component and Ｘ２ Zn Ｙ２ O Ｚ２ , or InO Ｘ１ In this specification, for example, when the atomic ratio of In to the element M in the first region is greater than the atomic ratio of In to the element M in the second region, the first region is said to have a higher In concentration than the second region.

[0206] IGZO is a common name and may refer to a compound of In, Ga, Zn, and O. A typical example is InGaO ３ (ZnO) ｍ１ (m1 is a natural number), or In （１＋ｘ０） Ga （１−ｘ０） O ３ (ZnO) ｍ０ (-1≦x0≦1, m0 is an arbitrary number).

[0207] The crystalline compound has a single crystal structure, a polycrystalline structure, or a CAAC structure. The CAAC structure is a crystal structure in which multiple IGZO nanocrystals have a c-axis orientation and are connected without being oriented in the a-b plane.

[0208] On the other hand, CAC-OS refers to a material structure of metal oxide. CAC-OS refers to a material structure containing In, Ga, Zn, and O, in which some regions observed as nanoparticles mainly composed of Ga and some regions observed as nanoparticles mainly composed of In are randomly dispersed in a mosaic pattern. Therefore, in CAC-OS, the crystal structure is a secondary element.

[0209] Note that the CAC-OS does not include a stacked structure of two or more films with different compositions, for example, a two-layer structure including a film containing In as the main component and a film containing Ga as the main component.

[0210] In addition, GaO Ｘ３ The region where In is the main component and Ｘ２ Zn Ｙ２ O Ｚ２ , or InO Ｘ１ In some cases, a clear boundary between the region where the main component is the chromatic aberration and the region where the chromatic aberration is the main component may not be observed.

[0211] When one or more elements selected from aluminum, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium are contained instead of gallium, the CAC-OS has a structure in which some regions observed to be nanoparticles containing the metal element as the main component and some regions observed to be nanoparticles containing In as the main component are randomly dispersed in a mosaic pattern.

[0212] The CAC-OS can be formed by sputtering without heating the substrate. When the CAC-OS is formed by sputtering, one or more of an inert gas (typically argon), oxygen gas, and nitrogen gas may be used as the deposition gas. The lower the flow rate of oxygen gas relative to the total flow rate of deposition gas during deposition, the more preferable it is. For example, the flow rate of oxygen gas is preferably 0% or more and less than 30%, and more preferably 0% or more and 10% or less.

[0213] CAC-OS has a characteristic that no clear peak is observed when measured using θ / 2θ scanning by an out-of-plane method, which is one of the X-ray diffraction (XRD) measurement methods. That is, the X-ray diffraction measurement reveals that the orientation of the measurement region in the a-b plane direction and the c-axis direction is not observed.

[0214] In addition, in an electron beam diffraction pattern obtained by irradiating CAC-OS with an electron beam (also referred to as a nanobeam electron beam) with a probe diameter of 1 nm, a ring-shaped region with high brightness and multiple bright spots within the ring-shaped region are observed. Therefore, the electron beam diffraction pattern indicates that the crystal structure of CAC-OS has an nc (nano-crystal) structure that does not have orientation in the planar and cross-sectional directions.

[0215] For example, in the case of CAC-OS in an In—Ga—Zn oxide, EDX mapping obtained by using energy dispersive X-ray spectroscopy (EDX) revealed that GaO Ｘ３ The region where In is the main component and Ｘ２ Zn Ｙ２ O Ｚ２ , or InO Ｘ１ It can be seen that the region where the main component is the crystalline silicon is unevenly distributed and mixed.

[0216] CAC-OS has a structure different from that of an IGZO compound in which metal elements are uniformly distributed, and has properties different from those of an IGZO compound. Ｘ３ and In Ｘ２ Zn Ｙ２ O Ｚ２ , or InO Ｘ１ The structure is such that the regions are separated into a mosaic of regions each containing one of the elements as the main component and a region each containing one of the elements as the main component.

[0217] Here, In Ｘ２ Zn Ｙ２ O Ｚ２ , or InO Ｘ１ The region where is the main component is GaO Ｘ３This region has higher conductivity than the region where the main component is In. Ｘ２ Zn Ｙ２ O Ｚ２ , or InO Ｘ１ When carriers flow through the region where In is the main component, the conductivity of the metal oxide is exhibited. Ｘ２ Zn Ｙ２ O Ｚ２ , or InO Ｘ１ The region where the main component is distributed in a cloud-like manner in the metal oxide can realize a high field-effect mobility (μ).

[0218] On the other hand, GaO Ｘ３ The region where the main components are In Ｘ２ Zn Ｙ２ O Ｚ２ , or InO Ｘ１ This region has higher insulating properties than the region where GaO is the main component. Ｘ３ By distributing regions in which the main components are such as these in the metal oxide, leakage current can be suppressed and good switching operation can be achieved.

[0219] Therefore, when CAC-OS is used in a semiconductor device, GaO Ｘ３ Insulation caused by Ｘ２ Zn Ｙ２ O Ｚ２ , or InO Ｘ１ The conductivity due to the high on-state current (I ｏｎ ), and high field-effect mobility (μ) can be achieved.

[0220] Furthermore, semiconductor elements using the CAC-OS have high reliability, making the CAC-OS ideal for various semiconductor devices such as displays.

[0221] Furthermore, since a transistor having a CAC-OS semiconductor layer has high field-effect mobility and high driving capability, a display device with a narrow frame width (also referred to as a narrow frame) can be provided by using the transistor in a driver circuit, typically a scan line driver circuit that generates gate signals.Furthermore, by using the transistor in a signal line driver circuit (particularly, a demultiplexer connected to an output terminal of a shift register included in the signal line driver circuit) included in the display device, a display device with a small number of wirings connected to the display device can be provided.

[0222] Furthermore, unlike transistors using low-temperature polysilicon, transistors having a CAC-OS semiconductor layer do not require a laser crystallization process. Therefore, even display devices using large-area substrates can be manufactured at low cost. Furthermore, in large-sized display devices with high resolution such as ultra-high-definition ("4K resolution," "4K2K," or "4K") and super-high-definition ("8K resolution," "8K4K," or "8K"), using a transistor having a CAC-OS semiconductor layer in a driver circuit or display portion enables writing in a short time and reduces display defects, which is preferable.

[0223] Alternatively, silicon may be used as a semiconductor in which a channel of a transistor is formed. Although amorphous silicon may be used as the silicon, it is preferable to use silicon having crystallinity. For example, it is preferable to use microcrystalline silicon, polycrystalline silicon, single crystal silicon, or the like. In particular, polycrystalline silicon can be formed at a lower temperature than single crystal silicon, and has higher field-effect mobility and higher reliability than amorphous silicon.

[0224] [Conductive Layer] Materials that can be used for conductive layers such as gates, sources, and drains of transistors, as well as various wirings and electrodes that constitute a display device, include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, and alloys containing these metals as main components. Films containing these materials can be used as a single layer or a stacked layer. For example, there are a single-layer structure of an aluminum film containing silicon, a two-layer structure of an aluminum film stacked on a titanium film, a two-layer structure of an aluminum film stacked on a tungsten film, a two-layer structure of a copper film stacked on a copper-magnesium-aluminum alloy film, a two-layer structure of a copper film stacked on a titanium film, a two-layer structure of a copper film stacked on a tungsten film, a three-layer structure of a titanium film or titanium nitride film, an aluminum film or copper film stacked on top of that, and a titanium film or titanium nitride film formed on top of that, a three-layer structure of a molybdenum film or molybdenum nitride film, an aluminum film or copper film stacked on top of that, and a molybdenum film or molybdenum nitride film formed on top of that, etc. Note that oxides such as indium oxide, tin oxide, or zinc oxide may also be used. In addition, using copper containing manganese is preferable because it improves the controllability of the shape by etching.

[0225] [Insulating Layer] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resins and epoxy resins, and resins having siloxane bonds such as silicone, as well as inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide.

[0226] In this specification, an oxynitride refers to a material whose composition contains more oxygen than nitrogen, and a nitride oxide refers to a material whose composition contains more nitrogen than oxygen. For example, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen.

[0227] Furthermore, the light emitting element is preferably provided between a pair of insulating films with low water permeability, which can prevent impurities such as water from entering the light emitting element and prevent a decrease in the reliability of the device.

[0228] Examples of the insulating film with low water permeability include a film containing nitrogen and silicon, such as a silicon nitride film or a silicon nitride oxide film, or a film containing nitrogen and aluminum, such as an aluminum nitride film. Alternatively, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, or the like may be used.

[0229] For example, the water vapor permeation rate of an insulating film with low water permeability is 1×10 −５ [g / (m ２ ·day)] or less, preferably 1 × 10 −６ [g / (m ２ ·day)] or less, more preferably 1 × 10 −７ [g / (m ２ ·day)] or less, more preferably 1 × 10 −８ [g / (m ２ ・day)] or less.

[0230] [Configuration Example of Display Module] A configuration example of a display module including a display device of one embodiment of the present invention will be described below.

[0231] 11A is a schematic perspective view of a display module 280. The display module 280 includes a display device 200 and an FPC 290. As the display device 200, any of the display devices exemplified in the above-described configuration example 2 (display device 200A to display device 200D) can be applied.

[0232] The display module 280 includes a substrate 201 and a substrate 202. The display module 280 also includes a display unit 281 on the substrate 202 side. The display unit 281 is a region that displays an image in the display module 280, and is a region where light from each pixel provided in a pixel unit 284 (described later) can be viewed. The display module 280 may also include a source driver IC 290b.

[0233] 11B is a perspective view schematically illustrating the configuration on the substrate 201 side. The substrate 201 has a configuration in which a circuit portion 282, a pixel circuit portion 283 on the circuit portion 282, and a pixel portion 284 on the pixel circuit portion 283 are stacked. The substrate 201 also has a terminal portion 285 for connecting to an FPC 290 in a portion of the substrate 201 that does not overlap with the pixel portion 284. The terminal portion 285 and the circuit portion 282 are electrically connected by a wiring portion 286 composed of a plurality of wirings.

[0234] The pixel section 284 has a plurality of periodically arranged pixels 284a. An enlarged view of one pixel 284a is shown on the right side of Fig. 11B. The pixel 284a has a light emitting element 120R, a light emitting element 120G, and a light emitting element 120B.

[0235] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically. The plurality of pixel circuits 283a may be arranged in a delta arrangement as shown in Fig. 11B. The delta arrangement allows pixel circuits to be arranged at high density, making it possible to provide a high-definition display device.

[0236] One pixel circuit 283a is a circuit that controls the light emission of three light-emitting elements included in one pixel 284a. One pixel circuit 283a may be configured to have three circuits that control the light emission of one light-emitting element. For example, the pixel circuit 283a may be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitor for each light-emitting element. In this case, a gate signal is input to the gate of the selection transistor, and a source signal is input to either the source or the drain. This realizes an active matrix display device.

[0237] The circuit portion 282 includes circuits for driving the pixel circuits 283a of the pixel circuit portion 283. For example, the circuit portion 282 preferably includes a gate line driver circuit, a source line driver circuit, etc. In addition, the circuit portion 282 may include an arithmetic circuit, a memory circuit, a power supply circuit, etc.

[0238] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit portion 282. An IC may be mounted on the FPC 290.

[0239] The display module 280 can be configured such that the pixel circuit unit 283 or the circuit unit 282 is stacked below the pixel unit 284, thereby enabling the aperture ratio (effective display area ratio) of the display unit 281 to be extremely high. For example, the aperture ratio of the display unit 281 can be 40% or more and less than 100%, preferably 50% or more and 95% or less, and more preferably 60% or more and 95% or less. Furthermore, the pixels 284a can be arranged at an extremely high density, enabling the resolution of the display unit 281 to be extremely high. For example, it is preferable that the pixels 284a be arranged in the display unit 281 at a resolution of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and 20,000 ppi or less, or 30,000 ppi or less.

[0240] Because such a display module 280 has extremely high resolution, it can be suitably used in VR devices such as head-mounted displays, or in glasses-type AR devices. For example, even in a configuration in which the display unit of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display unit 281, so even when the display unit is enlarged with lenses, the pixels are not visible, allowing for a highly immersive display. Furthermore, the display module 280 is not limited to this, and can be suitably used in electronic devices with relatively small display units. For example, it can be suitably used in the display unit of a wearable electronic device such as a wristwatch.

[0241] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0242] Embodiment 2 In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

[0243] 12A includes a pixel portion 502, a driver circuit portion 504, a protective circuit 506, and a terminal portion 507. Note that the display device of one embodiment of the present invention does not necessarily need to include the protective circuit 506.

[0244] The pixel portion 502 has a plurality of pixel circuits 501 arranged in X rows and Y columns (X and Y are each independently a natural number of 2 or more). Each pixel circuit 501 has a circuit for driving a display element.

[0245] The driver circuit unit 504 includes driver circuits such as a gate driver 504a that outputs scan signals to the gate lines GL_1 to GL_X and a source driver 504b that supplies data signals to the data lines DL_1 to DL_Y. The gate driver 504a may include at least a shift register. The source driver 504b may include, for example, a plurality of analog switches. Alternatively, the source driver 504b may include a shift register.

[0246] The terminal portion 507 is a portion provided with terminals for inputting power, control signals, image signals, and the like from an external circuit to the display device.

[0247] 12A is connected to various wirings, such as a gate line GL between the gate driver 504 a and the pixel circuit 501, or a data line DL between the source driver 504 b and the pixel circuit 501.

[0248] The gate driver 504 a and the source driver 504 b may be provided on the same substrate as the pixel portion 502, or a substrate on which a gate driver circuit or a source driver circuit is separately formed (for example, a drive circuit substrate formed of a single crystal semiconductor or a polycrystalline semiconductor) may be mounted on the substrate by COG or TAB (Tape Automated Bonding).

[0249] In particular, it is preferable to arrange the gate driver 504 a and the source driver 504 b below the pixel portion 502 .

[0250] Furthermore, the plurality of pixel circuits 501 shown in FIG. 12A can have, for example, the configuration shown in FIG. 12B.

[0251] 12B includes transistors 552 and 554, a capacitor 562, and a light-emitting element 572. The pixel circuit 501 is connected to a data line DL_n, a gate line GL_m, a potential supply line VL_a, a potential supply line VL_b, and the like.

[0252] Note that a high power supply potential VDD is applied to one of the potential supply lines VL_a and VL_b, and a low power supply potential VSS is applied to the other. The current flowing through the light-emitting element 572 is controlled in accordance with the potential applied to the gate of the transistor 554, thereby controlling the luminance of light emitted from the light-emitting element 572.

[0253] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0254] Embodiment 3 Hereinafter, a pixel circuit including a memory for correcting a gray scale displayed in a pixel, which can be applied to a display device of one embodiment of the present invention, and a display device including the pixel circuit will be described.

[0255] 13A shows a circuit diagram of a pixel circuit 400. The pixel circuit 400 includes a transistor M1, a transistor M2, a capacitor C1, and a circuit 401. The pixel circuit 400 is also connected to a wiring S1, a wiring S2, a wiring G1, and a wiring G2.

[0256] The transistor M1 has a gate connected to the wiring G1, one of a source and a drain connected to the wiring S1, and the other connected to one electrode of the capacitor C1. The transistor M2 has a gate connected to the wiring G2, one of a source and a drain connected to the wiring S2, and the other connected to the other electrode of the capacitor C1 and the circuit 401.

[0257] The circuit 401 is a circuit including at least one display element. Various elements can be used as the display element, but a light-emitting element such as an organic EL element or an LED element can be typically used. In addition to these, a liquid crystal element, a MEMS (Micro Electro Mechanical Systems) element, or the like can also be used.

[0258] The node connecting the transistor M1 and the capacitor C1 is referred to as a node N1, and the node connecting the transistor M2 and the circuit 401 is referred to as a node N2.

[0259] In the pixel circuit 400, the potential of the node N1 can be maintained by turning off the transistor M1. In addition, the potential of the node N2 can be maintained by turning off the transistor M2. In addition, by writing a predetermined potential to the node N1 via the transistor M1 while the transistor M2 is in the off state, the potential of the node N2 can be changed in accordance with the change in the potential of the node N1 due to capacitive coupling via the capacitor C1.

[0260] Here, the transistor including an oxide semiconductor, as exemplified in Embodiment 1, can be used as one or both of the transistors M1 and M2. Therefore, the potentials of the nodes N1 and N2 can be held for a long period of time due to an extremely low off-state current. Note that when the period for holding the potentials of the nodes is short (specifically, when the frame frequency is 30 Hz or higher), a transistor including a semiconductor such as silicon may be used.

[0261] [Driving Method Example] Next, an example of an operating method of the pixel circuit 400 will be described with reference to Fig. 13B. Fig. 13B is a timing chart relating to the operation of the pixel circuit 400. Note that, for ease of explanation, the influence of various resistances such as wiring resistance, parasitic capacitance of transistors or wiring, threshold voltage of transistors, etc. will not be taken into consideration here.

[0262] 13B, one frame period is divided into a period T1 and a period T2. The period T1 is a period in which a potential is written to the node N2, and the period T2 is a period in which a potential is written to the node N1.

[0263] [Period T1] In the period T1, a potential that turns on the transistor is applied to both the wiring G1 and the wiring G2. In addition, a fixed potential V ｒｅｆ is supplied to the line S2, and the first data potential V ｗ supply.

[0264] The node N1 is connected to the wiring S1 via the transistor M1. ｒｅｆ The node N2 is supplied with a first data potential V ｗ Therefore, the potential difference V ｗ -V ｒｅｆ is maintained.

[0265] [Period T2] Subsequently, in period T2, a potential that turns on the transistor M1 is applied to the wiring G1, and a potential that turns off the transistor M2 is applied to the wiring G2. In addition, a second data potential V ｄａｔａ A predetermined constant potential may be applied to the wiring S2, or the wiring S2 may be in a floating state.

[0266] The node N1 receives a second data potential V ｄａｔａ At this time, the second data potential V ｄａｔａ In other words, the circuit 401 receives the first data potential V ｗ 13B, the potential dV is shown as a positive value, but it may be a negative value. ｄａｔａ is the potential V ｒｅｆ It may be lower.

[0267] Here, the potential dV is roughly determined by the capacitance value of the capacitor C1 and the capacitance value of the circuit 401. When the capacitance value of the capacitor C1 is sufficiently larger than the capacitance value of the circuit 401, the potential dV is equal to the second data potential V ｄａｔａ The potential is close to

[0268] In this way, the pixel circuit 400 can generate a potential to be supplied to the circuit 401 including a display element by combining two types of data signals, and therefore, it is possible to perform gradation correction within the pixel circuit 400.

[0269] The pixel circuit 400 can also generate a potential that exceeds the maximum potential that can be supplied to the wirings S1 and S2. For example, when a light-emitting element is used, high dynamic range (HDR) display or the like can be performed. Furthermore, when a liquid crystal element is used, overdrive driving or the like can be realized.

[0270] 13C includes a circuit 401EL. The circuit 401EL includes a light-emitting element EL, a transistor M3, and a capacitor C2.

[0271] The transistor M3 has a gate connected to the node N2 and one electrode of the capacitor C2, and one of its source and drain connected to the potential V Ｈ The other electrode of the capacitor C2 is connected to a wiring that supplies a potential V ｃｏｍ The other electrode of the light-emitting element EL is connected to a wiring that supplies a potential V Ｌ Connect with the provided wiring.

[0272] The transistor M3 has a function of controlling the current supplied to the light-emitting element EL. The capacitor C2 functions as a storage capacitor. The capacitor C2 can be omitted if it is not necessary.

[0273] Although the anode side of the light-emitting element EL is connected to the transistor M3 in this example, the transistor M3 may be connected to the cathode side. Ｈ and potential V Ｌ The value of can be changed as appropriate.

[0274] In the pixel circuit 400EL, by applying a high potential to the gate of the transistor M3, a large current can flow through the light-emitting element EL, thereby realizing, for example, HDR display, etc. Furthermore, by supplying a correction signal to the wiring S1 or the wiring S2, it is possible to correct variations in the electrical characteristics of the transistor M3 or the light-emitting element EL.

[0275] It should be noted that the circuit is not limited to that shown in FIG. 13C, and a configuration in which a separate transistor or capacitor is added may also be used.

[0276] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0277] Embodiment 4 In this embodiment, structural examples of electronic devices to which a display device of one embodiment of the present invention is applied will be described.

[0278] The display device and the display module of one embodiment of the present invention can be applied to a display portion of an electronic device having a display function, etc. Examples of such electronic devices include electronic devices with relatively large screens such as television devices, notebook personal computers, monitor devices, digital signage, pachinko machines, and game machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound players.

[0279] In particular, the display device and the display module according to one embodiment of the present invention can have high resolution and can therefore be suitably used in electronic devices having a relatively small display area. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), VR devices such as head-mounted displays, and head-mountable wearable devices such as glasses-type AR devices.

[0280] 14A shows a perspective view of an eyeglass-type electronic device 700. The electronic device 700 has a pair of display panels 701, a pair of housings 702, a pair of optical members 703, a pair of mounting portions 704, and the like.

[0281] The electronic device 700 can project an image displayed on the display panel 701 onto a display area 706 of the optical member 703. Furthermore, because the optical member 703 is translucent, the user can see the image displayed in the display area 706 superimposed on a transmitted image visually recognized through the optical member 703. Therefore, the electronic device 700 is an electronic device capable of AR display.

[0282] One of the housings 702 is provided with a camera 705 that can capture an image in front of it. Although not shown, one of the housings 702 is provided with a connector to which a wireless receiver or a cable can be connected, and a video signal or the like can be supplied to the housing 702. The housing 702 can also be provided with an acceleration sensor such as a gyro sensor, which can detect the orientation of the user's head and display an image corresponding to that orientation in the display area 706. The housing 702 is preferably provided with a battery, which can be charged wirelessly or via a wired connection.

[0283] 14B , a method for projecting an image onto display area 706 of electronic device 700 will be described. A display panel 701, a lens 711, and a reflector 712 are provided inside housing 702. In addition, a portion of optical member 703 corresponding to display area 706 has a reflecting surface 713 that functions as a half mirror.

[0284] Light 715 emitted from the display panel 701 passes through the lens 711 and is reflected by the reflector 712 toward the optical member 703. Inside the optical member 703, the light 715 is repeatedly totally reflected by the end surface of the optical member 703 and reaches the reflecting surface 713, whereby an image is projected onto the reflecting surface 713. This allows the user to view both the light 715 reflected by the reflecting surface 713 and the transmitted light 716 that has passed through the optical member 703 (including the reflecting surface 713).

[0285] 14 shows an example in which the reflector 712 and the reflecting surface 713 each have a curved surface. This allows for greater freedom in optical design and allows for a thinner optical member 703 than when these surfaces are flat. Note that the reflector 712 and the reflecting surface 713 may also be flat.

[0286] A member having a mirror surface, preferably one with high reflectivity, can be used as the reflector 712. A half mirror utilizing reflection from a metal film may be used as the reflecting surface 713, but the transmittance of the transmitted light 716 can be increased by using a prism utilizing total reflection or the like.

[0287] Here, the housing 702 preferably has a mechanism for adjusting the distance between the lens 711 and the display panel 701 or the angle therebetween. This makes it possible to adjust the focus, enlarge or reduce the size of an image, etc. For example, one or both of the lens 711 and the display panel 701 may be configured to be movable in the direction of the optical axis.

[0288] Furthermore, the housing 702 preferably has a mechanism that can adjust the angle of the reflector 712. By changing the angle of the reflector 712, it is possible to change the position of the display area 706 where an image is displayed. This makes it possible to position the display area 706 in an optimal position according to the position of the user's eyes.

[0289] The display device or the display module of one embodiment of the present invention can be applied to the display panel 701. Therefore, the electronic device 700 can provide an extremely high-definition display.

[0290] 15A and 15B show perspective views of a goggle-type electronic device 750. Fig. 15A is a perspective view showing the front, top, and left side of electronic device 750, and Fig. 15B is a perspective view showing the back, bottom, and right side of electronic device 750.

[0291] The electronic device 750 includes a pair of display panels 751, a housing 752, a pair of mounting portions 754, a buffer member 755, and a pair of lenses 756. The pair of display panels 751 are provided inside the housing 752 at positions that can be viewed through the lenses 756.

[0292] The electronic device 750 is an electronic device for VR. A user wearing the electronic device 750 can view an image displayed on a display panel 751 through a lens 756. Also, by displaying different images on the pair of display panels 751, a three-dimensional display using parallax can be performed.

[0293] An input terminal 757 and an output terminal 758 are provided on the rear side of the housing 752. A cable for supplying a video signal from a video output device or the like, or for supplying power for charging a battery provided within the housing 752, can be connected to the input terminal 757. The output terminal 758 functions as, for example, an audio output terminal, and earphones, headphones, or the like can be connected. Note that if the device is configured to be able to output audio data via wireless communication or if audio is output from an external video output device, the audio output terminal need not be provided.

[0294] The housing 752 preferably has a mechanism that can adjust the left and right positions of the lens 756 and the display panel 751 so that they are optimally positioned according to the position of the user's eyes. Also, the housing 752 preferably has a mechanism that can adjust the focus by changing the distance between the lens 756 and the display panel 751.

[0295] The display device or display module of one embodiment of the present invention can be applied to the display panel 751. Therefore, the electronic device 750 can display images with extremely high resolution. This allows a user to feel a high sense of immersion.

[0296] The buffer member 755 is a portion that comes into contact with the user's face (forehead, cheeks, etc.). The close contact of the buffer member 755 with the user's face prevents light leakage and enhances the sense of immersion. It is preferable to use a soft material for the buffer member 755 so that it can closely contact the user's face when the user wears the electronic device 750. Materials such as rubber, silicone rubber, urethane, and sponge can be used. Furthermore, using a sponge or the like with a surface covered with cloth, leather (natural leather or synthetic leather), or the like, reduces the likelihood of gaps forming between the user's face and the buffer member 755, thereby effectively preventing light leakage. Furthermore, using such materials is preferable because they are pleasant to the touch and do not cause the user to feel cold when worn in cold weather. It is preferable to make components that come into contact with the user's skin, such as the buffer member 755 or the attachment portion 754, removable for easy cleaning or replacement.

[0297] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0298] In this example, Samples A and B having the structures shown in FIG. 17A and Samples C and D having the structures shown in FIG. 17B were fabricated. These samples were analyzed for deuterium D and oxygen isotopes ( １８ The results of evaluating the concentration of HCl (O) will be described below.

[0299] The structure shown in FIG. 17A includes a silicon substrate 10, a silicon oxide film 12 on the silicon substrate 10, a silicon oxynitride film 13 on the silicon oxide film 12, a silicon nitride film 14 on the silicon oxynitride film 13, a silicon oxynitride film 15 on the silicon nitride film 14, a silicon oxynitride film 16 on the silicon oxynitride film 15, and a silicon nitride film 20 on the silicon oxynitride film 16.

[0300] The structure shown in FIG. 17B has a silicon oxide film 17 instead of the silicon oxynitride film 16 in the structure shown in FIG. 17A.

[0301] First, a method for manufacturing Samples A to D having the structures shown in FIGS. 17A and 17B will be described.

[0302] First, a silicon substrate 10 was subjected to a heat treatment at 950° C. in an HCl atmosphere to form a silicon oxide film 12 having a thickness of 100 nm.

[0303] Next, a silicon oxynitride film 13 having a thickness of 100 nm was formed by PECVD.

[0304] Next, a silicon nitride film 14 having a thickness of 20 nm was formed by RF sputtering using a silicon target. The deposition gases for the silicon nitride film 14 were argon gas (20 sccm) and nitrogen gas (20 sccm), the deposition pressure was 3 mtorr, the substrate temperature was room temperature, and the distance between the target and the substrate was 185 mm. The RF power supply had a power of 1.5 kW.

[0305] Next, a silicon oxynitride film 15 having a thickness of 50 nm was formed by PECVD.

[0306] Next, in Sample A and Sample B, a silicon oxynitride film 16 having a thickness of 50 nm was formed by PECVD. Here, the silicon oxynitride film 16 was formed using deuterium (D ２ 200 sccm (D ２ :Ar=10sccm:190sccm), SiH ４ Gas 2.0 sccm, N ２ O gas was used at 800 sccm.

[0307] Next, in Samples C and D, a silicon oxide film 17 having a thickness of 50 nm was formed by RF sputtering. Here, the silicon oxide film 17 was formed using an oxygen isotope ( １８ 25 sccm of oxygen gas consisting of 2,4-dichloroethane (O) was used.

[0308] Next, a silicon nitride film 20 having a thickness of 20 nm was formed by RF sputtering using a silicon target under the same film formation conditions as those for the silicon nitride film 14.

[0309] Next, Sample A and Sample C were subjected to a heat treatment in a nitrogen atmosphere at 400° C. for 8 hours.

[0310] For Sample A and Sample B, the concentration of deuterium D was evaluated using a SIMS analyzer, and for Sample C and Sample D, the concentration of oxygen isotopes ( １８ The concentration of SiO was evaluated. The analysis was performed from the silicon substrate 10 side of each sample. The results of the SIMS analysis of Samples A and B are shown in FIG. 18A, and the results of the SIMS analysis of Samples C and D are shown in FIG. 18B.

[0311] 18A shows the concentration profile of deuterium D in the depth direction of each sample. In FIG. 18A, the horizontal axis represents the depth [nm] from the top surface of the silicon nitride film 20, and the vertical axis represents the concentration of deuterium D in the film [atoms / cm ３ ] is shown.

[0312] As shown in FIG. 18A, in the sample A and the sample B, the concentration of deuterium D in the layer below the silicon nitride film 14 is 1.0×10 １８ [atoms / cm ３ In other words, regardless of whether or not the sample is subjected to a heat treatment at 400° C. for 8 hours after formation, the diffusion of deuterium D contained in the silicon oxynitride film 16 into the layer below the silicon nitride film 14 is suppressed.

[0313] FIG. 18B shows the oxygen isotope distribution ( １８ 18B, the horizontal axis represents the depth [nm] from the top surface of the silicon nitride film 20, and the vertical axis represents the concentration profile of oxygen isotopes ( １８ O) concentration [atoms / cm ３ ] is shown.

[0314] As shown in FIG. 18B, in samples C and D, the oxygen isotope ( １８ O) concentration is 1.0 × 10 ２１ [atoms / cm ３ In other words, regardless of whether or not the sample was subjected to a heat treatment at 400° C. for 8 hours after formation, the oxygen isotopes ( １８ O) into layers below the silicon nitride film 14 is suppressed.

[0315] As described above, a silicon nitride film with a thickness of 20 nm sufficiently functions as a barrier insulating film against hydrogen and oxygen. By using such a silicon nitride film for the insulating layer 122 or the insulating layer 124 described in the previous embodiment, it is possible to suppress diffusion of hydrogen and oxygen into a light-emitting element or a semiconductor circuit using an oxide semiconductor. Furthermore, as shown in this example, a silicon nitride film functioning as a barrier insulating film sufficiently functions as a barrier insulating film even when formed at room temperature. That is, the barrier insulating film described in this example does not require high-temperature heat treatment during film formation. Therefore, such a barrier insulating film can be used for the insulating layer 124 without deteriorating the light-emitting element 120.

[0316] At least a part of the configurations, methods, and the like shown in this embodiment can be implemented in appropriate combination with the embodiment modes described in this specification.

[0317] C1: capacitance, C2: capacitance, DL_Y: data line, DL_1: data line, G1: wiring, G2: wiring, GL_X: gate line, GL_1: gate line, M1: transistor, M2: transistor, M3: transistor, N1: node, N2: node, RES1: resist, RES2: resist, RES3: resist, S1: wiring, S2: wiring, T1: period, T2: period, 10: silicon substrate, 12: silicon oxide film, 13: silicon oxynitride film, 14: silicon nitride film, 15: silicon oxynitride film, 16: silicon oxynitride film, 17: silicon oxide film, 20: nitride silicon dioxide film, 100: display device, 101: substrate, 111: conductive layer, 111a: conductive layer, 111b: conductive layer, 114: conductive layer, 114B: conductive layer, 114G: conductive layer, 114R: conductive layer, 115: EL layer, 115f: EL layer, 115a: EL layer, 115b: EL layer, 115B: EL layer, 115Bf: EL layer, 115G: EL layer, 115Gf: EL layer, 115R: EL layer, 115Rf: EL layer, 116: conductive layer, 116f: conductive layer, 117: insulator, 120: light-emitting element, 120B: light-emitting element, 120G: light-emitting element, 120R: light-emitting element, 121: insulating layer, 122: insulating layer, 124: insulating layer, 125: insulating layer, 131: plug, 162: insulating layer, 163: insulating layer, 164: adhesive layer, 165B: colored layer, 165G: colored layer, 165R: colored layer, 200: display device, 200A: display device, 200B: display device, 200C: display device, 200D: display device, 201: substrate, 202: substrate, 210: transistor, 211: conductive layer, 212: low resistance region, 213: insulating layer, 214: insulating layer, 215: element isolation layer, 220: transistor, 221: semiconductor layer, 223: insulating layer, 224: conductive layer, 225: conductive layer, 226 : insulating layer, 227: conductive layer, 228: insulating layer, 229: insulating layer, 230: transistor, 231: insulating layer, 232: insulating layer, 240: capacitor element, 241: conductive layer, 242: conductive layer, 243: insulating layer, 251: conductive layer, 252: conductive layer, 253: conductive layer, 261: insulating layer, 261a: insulating layer, 261b: insulating layer, 262: insulating layer, 263: insulating layer, 264: insulating layer, 265: insulating layer, 271: plug, 271a: conductive layer, 271b: conductive layer, 272: plug, 273: plug, 274: plug, 280: display module, 281: display section, 282: circuit section,283: pixel circuit section, 283a: pixel circuit, 284: pixel section, 284a: pixel, 285: terminal section, 286: wiring section, 290: FPC, 290b: source driver IC, 400: pixel circuit, 400EL: pixel circuit, 401: circuit, 401EL: circuit, 501: pixel circuit, 502: pixel section, 504: driver circuit section, 504a: gate driver, 504b: source driver, 506: protection circuit, 507: terminal section, 552: transistor, 554: transistor, 562: capacitance element, 57 2: light-emitting element, 700: electronic device, 701: display panel, 702: housing, 703: optical member, 704: mounting portion, 705: camera, 706: display area, 711: lens, 712: reflector, 713: reflective surface, 715: light, 716: transmitted light, 750: electronic device, 751: display panel, 752: housing, 754: mounting portion, 755: buffer member, 756: lens, 757: input terminal, 758: output terminal, 4411: light-emitting layer, 4412: light-emitting layer, 4413: light-emitting layer, 4420: layer, 4430: layer,

Claims

1. A transistor on the substrate; a first insulating layer over the transistor; a second insulating layer on the first insulating layer; a plug disposed so as to be embedded in the first insulating layer and the second insulating layer; a light emitting element on the second insulating layer, The light-emitting element is A first conductive layer; and an electroluminescent layer on the first conductive layer; a second conductive layer on the EL layer, the plug electrically connects one of a source and a drain of the transistor to the first conductive layer; the second insulating layer has a region in contact with the first insulating layer in a region not overlapping with the first conductive layer, The second insulating layer has a higher ability to suppress hydrogen diffusion than the first insulating layer. Display device.

2. In claim 1, The second insulating layer comprises nitrogen and silicon.

3. In claim 1, the second insulating layer includes a first layer and a second layer on the first layer; the first layer comprises nitrogen and silicon; The second layer comprises oxygen and aluminum.

4. In claim 1, the second insulating layer includes a first layer and a second layer on the first layer; the first layer comprises nitrogen and silicon; The second layer comprises oxygen and hafnium.

5. In any one of claims 1 to 4, A third insulating layer is disposed over the light emitting element; The display device, wherein the third insulating layer has a higher ability to suppress hydrogen diffusion than the first insulating layer.

6. In claim 5, The display device, wherein the third insulating layer is in contact with the second insulating layer in a region that does not overlap with the light-emitting element.

7. In claim 5 or 6, the third insulating layer includes a third layer and a fourth layer on the third layer; the third layer comprises oxygen and aluminum; The fourth layer comprises nitrogen and silicon.

8. In any one of claims 1 to 7, The electroluminescent layer covers a side surface of the first conductive layer.

9. In any one of claims 1 to 8, The display device, wherein the first conductive layer is reflective to visible light.

10. In any one of claims 1 to 9, The second conductive layer is transmissive and reflective to visible light.

11. In any one of claims 1 to 10, the substrate is a silicon substrate, The display device, wherein the transistor has silicon in a channel formation region.

12. In any one of claims 1 to 11, an oxide semiconductor film is provided on the substrate; The display device, wherein the transistor includes the oxide semiconductor film in a channel formation region.