Display devices and electronic devices

Abstract

A low-cost and highly reliable display device is provided. This display device has a structure comprising light-emitting diodes (LEDs) included in a pixel circuit, transistors included in the pixel circuit, and transistors included in a driving circuit of the pixel circuit, all stacked in a manner with overlapping areas. By employing this structure, the display device can be miniaturized. Furthermore, this display device can be manufactured by bonding multiple LEDs to a circuit board on which transistors are formed in a single process. Therefore, the manufacturing cost of the display device can be reduced.

Description

Technical Field

[0001] One embodiment of the present invention relates to a display device.

[0002] Note that one embodiment of the present invention is not limited to the above-described technical fields. As an example of the technical field of one embodiment of the present invention, examples include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, electronic devices, lighting equipment, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), and driving or manufacturing methods of the above devices. Prior Technology

[0003] Display devices that utilize highly reliable light-emitting diodes (LEDs) in display devices (also known as display elements) have been proposed (e.g., Patent Document 1, Patent Document 2). In particular, display devices using Micro LEDs have advantages such as high brightness, high contrast, and long lifespan, and therefore, as a new generation of display devices, their research and development is very active. [Patent Literature]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2008-58535 [Patent Document 2] U.S. Patent Application Publication No. 2014 / 0367705 Summary of the Invention

[0005] When forming LEDs that emit red (R), green (G), or blue (B) light, compound semiconductors with band gaps suitable for each emission color are required. However, even compound semiconductors with the same elemental composition can have their band gaps altered by adjusting the atomic ratio of the elements or introducing impurities. When LEDs emitting red, green, and blue light can be formed separately on the same substrate, the manufacturing process of display devices can be simplified.

[0006] However, manufacturing LED chips with different emitting colors on the same semiconductor substrate requires numerous processes and is currently quite difficult. Therefore, the following process was adopted: LED chips are manufactured using different semiconductor substrates for each emitting color, and they are picked up and placed one by one to create a display device.

[0007] However, the aforementioned LED chip loading and unloading process requires a considerable amount of time, thus failing to reduce manufacturing costs. To address this issue, a structure capable of simultaneously loading and unloading multiple LED chips is preferable. Furthermore, when employing a color-changing technology using monochrome LED chips, mass production of LED chips can reduce manufacturing costs.

[0008] Therefore, one objective of one embodiment of the present invention is to provide a low-cost and highly reliable display device. Furthermore, one objective of one embodiment of the present invention is to provide a compact display device. Furthermore, one objective of one embodiment of the present invention is to provide a display device with high display quality. Furthermore, one objective of one embodiment of the present invention is to provide a display device with low power consumption. Furthermore, one objective of one embodiment of the present invention is to reduce the manufacturing cost of display devices using Micro LEDs. Furthermore, one objective of one embodiment of the present invention is to provide a novel display device. Furthermore, one objective of one embodiment of the present invention is to provide a method for manufacturing the above-described display device.

[0009] Note that the description of these objectives does not preclude the existence of other objectives. One embodiment of the invention does not need to achieve all of the above objectives. Objectives other than those described above can be extracted from the specification, drawings, and claims.

[0010] One embodiment of the present invention is a display device, comprising a transistor, a reflective layer, a light-emitting diode, a first insulating layer, and a second insulating layer, wherein the transistor, the reflective layer, and the light-emitting diode each have overlapping regions, the reflective layer is disposed on the transistor through the first insulating layer, and the light-emitting diode is disposed on the reflective layer through the second insulating layer. The light-emitting diode includes a semiconductor layer, and the semiconductor layer has a region in contact with the second insulating layer.

[0011] The aforementioned display device may further include one or both of a color conversion layer and a color layer, and a third insulating layer. One or both of the color conversion layer and the color layer may be disposed on the light-emitting diode through the third insulating layer. The color conversion layer preferably includes a phosphor or a quantum dot.

[0012] In the above-mentioned display device, preferably, the transistor includes a metal oxide in the channel forming region, the metal oxide comprising In, Zn and M (M is one or more of Al, Ti, Ga, Ge, Sn, Y, Zr, La, Ce, Nd and Hf).

[0013] Another embodiment of the present invention is a display device, including a first layer, a second layer, a third layer, and a fourth layer, wherein the second layer and the third layer are disposed between the first layer and the fourth layer, the second layer is disposed between the first layer and the third layer, the first layer includes a first transistor, the second layer includes a second transistor, the third layer includes a reflective layer, and the fourth layer includes a light-emitting diode. The first transistor, the second transistor, the reflective layer, and the light-emitting diode each have overlapping regions. A first insulating layer is disposed between the first transistor and the second transistor, a second insulating layer is disposed between the second transistor and the reflective layer, and a third insulating layer is disposed between the reflective layer and the light-emitting diode. The light-emitting diode includes a semiconductor layer, and the semiconductor layer has a region in contact with the third insulating layer.

[0014] The aforementioned display device may further include a fifth layer, which may be configured such that a fourth layer is sandwiched between the fifth layer and the third layer. The fifth layer may include one or both of a color conversion layer and a color layer. The color conversion layer and the color layer, the first transistor, the second transistor, the reflective layer, and the light-emitting diode may each have overlapping areas. A fourth insulating layer may be disposed between the light-emitting diode and one or both of the color conversion layer and the color layer.

[0015] In the aforementioned display device, the color conversion layer preferably includes phosphors or quantum dots.

[0016] In the aforementioned display device, the first transistor preferably contains silicon in the channel forming region. Additionally, it is preferable that the second transistor includes a metal oxide in the channel forming region, the metal oxide comprising In, Zn, and M (M being one or more of Al, Ti, Ga, Ge, Sn, Y, Zr, La, Ce, Nd, and Hf).

[0017] In the above-mentioned display device, the first transistor can be a component of the circuit driving the pixel circuit, and the second transistor can be a component of the pixel circuit.

[0018] In both embodiments of the present invention described above, the semiconductor layer is preferably a compound semiconductor containing elements of Group 13 and Group 15. Furthermore, the light-emitting diode is preferably one that emits blue light, blue-violet light, violet light, or ultraviolet light.

[0019] According to one embodiment of the present invention, a low-cost and highly reliable display device can be provided. Furthermore, a compact display device can be provided. Furthermore, a display device with high display quality can be provided. Furthermore, a display device with low power consumption can be provided. Furthermore, the manufacturing cost of display devices using Micro LEDs can be reduced. Furthermore, a novel display device can be provided. Furthermore, a method for manufacturing the above-described display device can be provided.

[0020] Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not require all of the above-described effects to be achieved. Effects other than those described above can be extracted from the specification, drawings, and claims. Simple Explanation of the Diagram

[0021] [Figure 1] is a diagram illustrating the display device. Figures 2A and 2B illustrate the display device. Figures 3A to 3D illustrate the manufacturing method of a light-emitting diode. Figures 4A to 4D illustrate the manufacturing method of a light-emitting diode. Figures 5A to 5D illustrate the manufacturing method of a light-emitting diode. Figures 6A and 6B illustrate the display device. Figures 6C through 6E illustrate the transistor. [Figure 7A] and [Figure 7B] are diagrams illustrating the display device. Figures 8A and 8B illustrate the display device. [Figure 9] is a diagram illustrating the display device. [Figure 10] is a diagram illustrating the display device. [Figure 11] is a diagram illustrating the display device. [Fig. 12A] is a top view illustrating an example of a transistor. [Fig. 12B] to [Fig. 12D] are cross-sectional views illustrating an example of a transistor. [Figure 13] is a circuit diagram illustrating an example of a pixel circuit. [Figure 14A] and [Figure 14B] are diagrams illustrating an example of an electronic device. [Figure 15A] and [Figure 15B] are diagrams illustrating an example of an electronic device. [Figure 16A] and [Figure 16B] are diagrams illustrating an example of an electronic device. [Figure 17A] and [Figure 17B] are diagrams illustrating an example of an electronic device. Figures 18A to 18D are illustrations of an example of an electronic device. Figures 19A to 19F are illustrations of an example of an electronic device. Implementation

[0022] The embodiments will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and those skilled in the art will readily understand that its methods and details can be varied in many ways without departing from the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited only to the contents described in the embodiments shown below.

[0023] Note that in the inventive structures described below, the same symbols are used in different figures to represent the same parts or parts with the same function, and repeated descriptions are omitted. Furthermore, when representing parts with the same function, the same shading lines are sometimes used, without additional element symbols.

[0024] Furthermore, for ease of understanding, the positions, sizes, and extents of the components shown in the drawings may not represent their actual positions, sizes, and extents. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and extents disclosed in the drawings.

[0025] Furthermore, depending on the situation or state, the "film" and "layer" can be interchanged. For example, a "conductive layer" can be changed into a "conductive film." Additionally, for example, an "insulating film" can be changed into an "insulating layer."

[0026] Implementation Method 1 In this embodiment, a display device according to one embodiment of the present invention will be described with reference to the drawings.

[0027] The display device of this embodiment has a structure comprising a light-emitting diode included in a pixel circuit, a transistor included in the pixel circuit, and a transistor included in the driving circuit of the pixel circuit, and these components are stacked in such a way that they have overlapping areas. By adopting this structure, the display device can be miniaturized.

[0028] In the display device manufacturing method of this embodiment, multiple light-emitting diodes (LEDs) can be bonded to a circuit board on which transistors are formed in a single process. Therefore, even when manufacturing display devices with a high pixel count or high resolution, the manufacturing time of the display device can be shortened compared to methods that mount LEDs one by one onto the circuit board. Furthermore, the manufacturing difficulty of the display device can be reduced.

[0029] Figure 1 shows a cross-sectional view of a display device 100A according to an embodiment of the present invention. The display device 100A has a structure in which a layer 11, in which a driving circuit including a pixel circuit is provided, including a transistor, etc., is provided, a layer 12, in which a transistor including a pixel circuit is provided, is provided, a layer 13, in which a reflective layer is provided, and a layer 14, in which a light-emitting device (also called a light-emitting element) including a light-emitting diode included in the pixel circuit is provided, is stacked in sequence.

[0030] Note that in this embodiment, the display device is described in multiple layers for ease of understanding, but the boundaries between layers are not strictly defined. For example, even a component described as a component of layer 11 in this embodiment can be considered a component of layer 12 if it is located near the boundary between layer 11 and layer 12. Furthermore, a component can be located in a layer other than layer 11 as long as its function is not impaired. Additionally, in one embodiment of the invention, other insulating and conductive layers besides the insulating and conductive layers included in each layer may be provided as needed. Furthermore, a portion of the insulating and conductive layers included in each layer may be omitted as needed.

[0031] Layer 11 includes, for example, a transistor 130 comprising components such as a driving circuit for pixel circuitry (one or both of a gate driver and a source driver). Because the transistor 130 requires high-speed operation, it is preferable to use a transistor (hereinafter, Si transistor) that incorporates silicon (monocrystalline silicon, polycrystalline silicon, or amorphous silicon, etc.) in the channel formation region. Figure 1 shows an example of using monocrystalline silicon as a substrate 151, in which the transistor 130 includes a channel formation region.

[0032] A portion of the driving circuit for the pixel circuit can also be housed within an external IC chip connected to the pixel circuit.

[0033] Transistor 130 includes a conductive layer 135, an insulating layer 134, an insulating layer 136, and a pair of low-resistance regions 133. The conductive layer 135 serves as the gate. The insulating layer 134 is located between the conductive layer 135 and the substrate 151 and serves as the gate insulating layer. The insulating layer 136 is disposed covering the sides of the conductive layer 135 and serves as a sidewall. The pair of low-resistance regions 133 are regions in the substrate 151 doped with impurities; one serves as the source of transistor 130, and the other serves as the drain of transistor 130. Additionally, a component separation layer 132 is disposed around transistor 130.

[0034] An insulating layer 139 is provided over the transistor 130, and a conductive layer 138 is provided on the insulating layer 139. Furthermore, a conductive layer 137 is embedded in an opening provided in the insulating layer 139. The conductive layer 138 is electrically connected to one of a pair of low-resistance regions 133 via the conductive layer 137. Additionally, an insulating layer 141 is provided over the conductive layer 138. The conductive layer 138 serves as wiring. This wiring allows other transistors, pixel circuits, or other circuits in a circuit that includes the transistor 130 as a component to be electrically connected to each other.

[0035] Layer 12 includes a transistor 120, insulating layers 142, 162, 181, 182, 183, conductive layers 184a, 184b, 185, 186, 194, and 195, which are components of the pixel circuit. One or more of these components are sometimes considered components of the transistor, but in this embodiment, they are not included in the description of transistor components. The conductive and insulating layers included in layer 12 may have a single-layer structure or a stacked structure.

[0036] An insulating layer 142 is disposed on layer 11. The insulating layer 142 serves as an oxygen barrier layer to prevent impurities such as water or hydrogen from diffusing from layer 11 to transistor 120 and to prevent oxygen from escaping from metal oxide layer 165 to the insulating layer 142 side. As the insulating layer 142, for example, a film that is less susceptible to hydrogen and oxygen diffusion than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film, can be used.

[0037] The transistor 120 includes a conductive layer 161, an insulating layer 163, an insulating layer 164, a metal oxide layer 165, a pair of conductive layers 166, an insulating layer 167, a conductive layer 168, etc. Specific examples of transistors that can be used in a display device according to one embodiment of the present invention will be described in detail in Embodiment 3.

[0038] The transistor 120 is preferably a transistor (hereinafter, OS transistor) that includes a metal oxide layer 165 in the channel forming region. The metal oxide layer 165 has a first region overlapping one of a pair of conductive layers 166, a second region overlapping the other of the pair of conductive layers 166, and a third region between the first region and the second region.

[0039] OS transistors do not require bonding processes and can be formed in areas overlapping with Si transistors, separated by insulating layers. Therefore, multilayer devices can be manufactured with simple processes, thereby reducing manufacturing costs.

[0040] Furthermore, compared to transistors using amorphous silicon, OS transistors offer advantages such as high mobility enabling high-speed operation and high reliability. Additionally, the metal oxides used in OS transistors can be formed during the film deposition process, eliminating the need for laser devices required in the crystallization process of polycrystalline silicon. Therefore, by using OS transistors, inexpensive and highly reliable display devices can be manufactured.

[0041] A conductive layer 161 and an insulating layer 162 are disposed on the insulating layer 142, and an insulating layer 163 is disposed covering the conductive layer 161 and the insulating layer 162. An insulating layer 164 is disposed on the insulating layer 163, and a metal oxide layer 165 is disposed on the insulating layer 164.

[0042] Conductive layer 161 is used as a gate electrode, and insulating layers 163 and 164 are used as gate insulating layers. Conductive layer 161 has a region that overlaps with metal oxide layer 165 through insulating layers 163 and 164. Insulating layer 163 is preferably formed using the same material used as a barrier layer as insulating layer 142. Insulating layer 164 in contact with metal oxide layer 165 is preferably an oxide insulating film such as silicon oxide film.

[0043] A pair of conductive layers 166 are separately disposed on the metal oxide layer 165. One of the pair of conductive layers 166 is used as the source of a transistor, and the other is used as the drain. An insulating layer 181 is disposed covering the metal oxide layer 165 and the pair of conductive layers 166, and an insulating layer 182 is disposed on the insulating layer 181.

[0044] Openings extending to the metal oxide layer 165 are provided in insulating layers 181 and 182, and insulating layers 167 and 168 are embedded within these openings. These openings are located at a position overlapping a third region of the metal oxide layer 165. Insulating layer 167 has regions overlapping with the sides of insulating layers 181 and 182. Conductive layer 168 has regions overlapping with the sides of insulating layers 181 and 182, separated by insulating layers 167.

[0045] The conductive layer 168 is used as the gate electrode, and the insulating layer 167 is used as the gate insulating layer. The conductive layer 168 has a region that overlaps with the metal oxide layer 165 through the insulating layer 167.

[0046] Furthermore, insulating layers 183 and 185 are provided on the top surface covering insulating layers 182, 167 and conductive layers 168.

[0047] The insulating layers 181 and 183 are preferably formed using the same material used as the barrier layer as the insulating layer 142. By covering the pair of conductive layers 166 with the insulating layer 181, oxidation of the pair of conductive layers 166 due to oxygen contained in the insulating layer 182 can be suppressed.

[0048] A plug electrically connected to one of a pair of conductive layers 166 and conductive layer 195 is embedded in an opening provided in insulating layers 181, 182, 183, and 185. The plug may include a conductive layer 184b in contact with the side of the opening and the top surface of one of the pair of conductive layers 166, and a conductive layer 184a embedded inside the conductive layer 184b. The conductive layer 184b is preferably formed using a conductive material that does not readily diffuse hydrogen and oxygen.

[0049] The insulating layer 185 is provided with a conductive layer 195, a conductive layer 194, and an insulating layer 186. The conductive layer 195 is used as wiring to electrically connect the transistor 120 to the light-emitting diode 110 disposed in the layer 14. The conductive layer 194 is used as a plug to electrically connect the transistor 120 to the light-emitting diode 110.

[0050] Materials that can be used for conductive layers 194 and 195 include, for example, metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, tin, zinc, silver, platinum, gold, molybdenum, tantalum, or tungsten, or alloys thereof as the main components (e.g., an alloy of silver, palladium, and copper (Ag-Pd-Cu(APC))). Alternatively, oxides such as tin oxide or zinc oxide can also be used. Furthermore, conductive layers 194 and 195 can also have a laminated structure using any two or more of the aforementioned materials.

[0051] The insulating layer 186 may have a planarization function. The insulating layer 186 is preferably formed by using one or more single layers or stacks of inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, aluminum oxide, hafnium oxide, and titanium nitride.

[0052] Layer 13 is provided with a conductive layer 189, a conductive layer 192, a reflective layer 193, and an insulating layer 187 covering them. The conductive layers 189 and 192 are used as wiring for electrical connection with the light-emitting diode 110. The reflective layer 193 is disposed at a position overlapping the light-emitting diode 110 disposed in layer 14, and has the function of reflecting light emitted from the light-emitting diode 110 to the side of layer 12. By providing the reflective layer 193, the light emitted by the light-emitting diode 110 can be adjusted to be emitted towards the outside of layer 14 (the side of layer 14 opposite to the surface of layer 13).

[0053] The reflective layer 193 preferably also has a region overlapping with the transistor 120 included in layer 12. By means of the reflective layer 193, light emitted from the light-emitting diode 110 towards layer 12 can be blocked, and characteristic variations when light is irradiated onto the transistor 120 can be suppressed. For the same reason, the reflective layer 193 preferably also has a region overlapping with the transistor 130 included in layer 11.

[0054] The transistor having a region overlapping with the reflective layer 193 can also be part of the transistors included in layers 12 and 11. As long as the changes in transistor characteristics caused by light irradiation are within acceptable limits, light shielding is not required. In addition, wiring or electrodes provided in layers 12, 13, etc., are sometimes used as light-shielding layers.

[0055] The reflective layer 193 is preferably formed of a material with high reflectivity for the light emitted by the light-emitting diode 110 included in layer 14. Examples include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, tin, zinc, silver, platinum, gold, molybdenum, tantalum, or tungsten, or alloys thereof as the main components (such as an alloy of silver, palladium, and copper (Ag-Pd-Cu(APC))). Alternatively, the reflective layer 193 may also have a stacked structure using any two or more of the aforementioned materials.

[0056] An insulating layer 187 is provided on the conductive layer 189, the conductive layer 192, and the reflective layer 193. An insulating layer 188 is provided on the insulating layer 187. In addition, an insulating layer 102 is provided on the insulating layer 188.

[0057] One of the pair of conductive layers 166 of transistor 120 is electrically connected to conductive layer 189 via conductive layers 184a and 184b.

[0058] Insulating layers 186 and 187 may have a planarization function. Insulating layers 186 and 187 are preferably formed by using one or more single layers or stacks of inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, aluminum oxide, hafnium oxide, and titanium nitride.

[0059] Note that in this specification, silicon oxynitride refers to a material containing silicon, oxygen, and nitrogen, with an oxygen content exceeding a nitrogen content. Additionally, silicon oxynitride refers to a material containing silicon, oxygen, and nitrogen, with a nitrogen content exceeding an oxygen content.

[0060] The insulating layer 188 can be used as a barrier layer to prevent impurities (hydrogen, water, etc.) from diffusing from layer 14 to transistor 120. As the insulating layer 188, for example, a film that is less susceptible to hydrogen and oxygen diffusion than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film, can be used.

[0061] The insulating layer 102 is preferably formed by using one or more single layers or stacks of inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, aluminum oxide, hafnium oxide, and titanium nitride.

[0062] Transistor 120 can be used as a transistor constituting a pixel circuit. Transistor 130 can be used as a transistor constituting a driving circuit (one or both of a gate driver and a source driver) used to drive the pixel circuit. Note that transistor 130 can also be a transistor constituting a pixel circuit. Furthermore, transistors 120 and 130 can also be used as transistors constituting various circuits such as arithmetic circuits or memory circuits.

[0063] By adopting this structure, components such as transistors included in the pixel circuit can be formed directly under the light-emitting diode, as well as components such as transistors included in the driving circuit. Therefore, compared with the case where the driving circuit is set on the outside of the display section, the display device can be miniaturized. In addition, a display device with a narrow bezel (narrow non-display area) can be realized.

[0064] Layer 14 includes a light-emitting diode 110, an insulating layer 103, and an insulating layer 104. Insulating layers 102, 103, and 104 can all have a single-layer structure or a multilayer structure.

[0065] The light-emitting diode 110 includes a semiconductor layer 113, a light-emitting layer 114, and a semiconductor layer 115, which are stacked sequentially on layer 113. The light-emitting diode 110 may also include multiple layers.

[0066] An insulating layer 103 is disposed covering an insulating layer 102, a semiconductor layer 113, a light-emitting layer 114, and a semiconductor layer 115. Preferably, the insulating layer 103 has a planarization function. An insulating layer 104 is disposed on the insulating layer 103.

[0067] A conductive layer 190a and a conductive layer 191a are provided in the opening provided in the insulating layer 103. A conductive layer 190c and a conductive layer 191c are provided in the openings provided in the insulating layers 103, 102, 188, and 187. The conductive layers 190a, 190c, 191a, and 191c are used as plugs for electrically connecting the various components.

[0068] Semiconductor layer 113 is electrically connected to conductive layer 189 via conductive layers 190a, 190b, and 190c. Semiconductor layer 115 is electrically connected to conductive layer 192 via conductive layers 191a, 191b, and 191c. Here, conductive layers 190b and 191b are used as interconnect wiring.

[0069] Insulating layers 103, 104, 139, 141, 162, 182, and 185 are preferably formed by using one or more single layers or stacks of inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, aluminum oxide, hafnium oxide, and titanium nitride.

[0070] Materials that can be used for conductive layers 190a to 190c and conductive layers 191a to 191c include, for example, metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, tin, zinc, silver, platinum, gold, molybdenum, tantalum, or tungsten, or alloys thereof as the main component (e.g., alloys of silver, palladium, and copper (Ag-Pd-Cu(APC))). Alternatively, oxides such as tin oxide or zinc oxide may also be used. Furthermore, conductive layers 190a to 190c and conductive layers 191a to 191c may also have a laminated structure using any two or more of the aforementioned materials.

[0071] A light-emitting layer 114 is sandwiched between semiconductor layers 113 and 115. In the light-emitting layer 114, electrons and holes bond to emit light. One of the semiconductor layers 113 and 115 can be an n-type semiconductor layer, and the other can be a p-type semiconductor layer. Alternatively, the light-emitting layer 114 can be an n-type, i-type, or p-type semiconductor layer.

[0072] The stacked structure, including semiconductor layer 113, light-emitting layer 114, and semiconductor layer 115, is formed to emit light in a manner that produces red, green, blue, blue-violet, purple, or ultraviolet light. This stacked structure can be, for example, composed of compounds containing Group 13 and Group 15 elements (also known as Group 3-5 compounds). Examples of Group 13 elements include aluminum, gallium, and indium. Examples of Group 15 elements include nitrogen, phosphorus, arsenic, and antimony.

[0073] For example, gallium-phosphorus compounds, gallium-arsenic compounds, gallium-aluminum-arsenic compounds, aluminum-gallium-indium-phosphorus compounds, gallium nitride, indium-gallium nitride compounds, selenium-zinc compounds, etc., can be used to form pn junctions or pin junctions to manufacture light-emitting diodes for the purpose of emitting light. In addition, compounds other than those mentioned above can also be used.

[0074] Furthermore, the pn junction or pin junction can be a homojunction, a heterojunction, or a double heterojunction. In addition, LEDs with quantum well junctions or LEDs using nanopillars can also be used.

[0075] For example, materials such as gallium nitride can be used as light-emitting diodes (LEDs) emitting light in the ultraviolet to blue wavelength range. Materials such as indium gallium nitride compounds can be used as LEDs emitting light in the ultraviolet to green wavelength range. Materials such as aluminum-gallium-indium-phosphorus compounds or gallium-arsenide compounds can be used as LEDs emitting light in the infrared wavelength range. Materials such as gallium-arsenide compounds can be used as LEDs emitting light in the infrared wavelength range.

[0076] When multiple light-emitting diodes 110 disposed on the same surface have a structure capable of emitting light of different colors such as R (red), G (green), and B (blue), color images can be displayed even without using a color conversion layer. Therefore, a process for forming a color conversion layer is not required, thereby reducing the manufacturing cost of the display device.

[0077] Alternatively, all light-emitting diodes 110 disposed on the same surface may also have a structure that emits light of the same color. In this case, the light emitted from the light-emitting layer 114 is extracted to the outside of the display device through one or both of the color conversion layer and the color layer. This structure will be described in detail in Embodiment 2 of the display device.

[0078] Alternatively, the display device of this embodiment may also include a light-emitting diode that emits infrared light. The light-emitting diode that emits infrared light can, for example, be used as a light source for an infrared light sensor.

[0079] Note that although FIG1 shows that the reflective layer 193 can be formed using the same material and process as the conductive layers 189 and 192, the reflective layer 193 can also be disposed in a different layer than the layers on which the conductive layers 189 and 192 are disposed. For example, as shown in FIG2A, the reflective layer 193 can also be disposed on the insulating layer 188 and covered by the insulating layer 102. Alternatively, as shown in FIG2B, the reflective layer 193 can also be disposed between the insulating layer 102 and the light-emitting diode 110. In this case, the reflective layer 193 can also contact the semiconductor layer 113 and be used as an electrode layer in the light-emitting diode 110.

[0080] The light-emitting diode 110 is fabricated as shown in FIG1 after a separately formed stacked structure of a compound semiconductor or the like is fixed to the insulating layer 102. The method of forming the light-emitting diode 110 will be explained using FIGS. 3A to 3D, 4A to 4D and 5A to 5D.

[0081] First, a release layer 310, a semiconductor layer 113a, a light-emitting layer 114a, and a semiconductor layer 115a are formed on the substrate 300 (see Figure 3A).

[0082] As the substrate 300, a single-crystal substrate such as a sapphire (Al2O3) substrate, a silicon carbide (SiC) substrate, a silicon (Si) substrate, or a compound semiconductor can be used. As the compound semiconductor, a compound containing elements from Group 13 and Group 15 can be used. When epitaxially growing the light-emitting layer 114a, the substrate 300 is preferably made of a material whose lattice constant is the same as or slightly different from that of the light-emitting layer 114a.

[0083] For example, when forming a light-emitting diode that emits red light, the light-emitting layer 114a, etc., can be made of aluminum gallium arsenide (AlGaAs). In this case, the substrate 300 can be made of a gallium arsenide (GaAs) substrate, etc.

[0084] A release layer 310 is provided on the substrate 300. The release layer 310 is provided for peeling off the stack including the semiconductor layer 113a, the light-emitting layer 114a, and the semiconductor layer 115a from the substrate 300. The release layer 310 is preferably made of a material that is easily removed in subsequent processes such as wet etching. For example, aluminum arsenide (AlAs) can be used.

[0085] A semiconductor layer 113a, a light-emitting layer 114a, and a semiconductor layer 115a are disposed on the release layer 310. Semiconductor layers 113a and 115a are used as cladding layers; for example, one of semiconductor layers 113a and 115a may have p-type conductivity, while the other may have n-type conductivity. Note that although the basic structure of the light-emitting diode is described here as a three-layer structure, more layers may be included. Alternatively, a structure may be formed by adding impurities to a portion of the light-emitting layer 114a to create a pn junction. Semiconductor layers 113a, 114a, and 115a can be formed, for example, by epitaxial growth using a method such as MOCVD (metal-organic chemical vapor deposition).

[0086] Next, an adhesive layer 320 and a substrate 330 are disposed on the semiconductor layer 115a (see Figure 3B). The substrate 330 can be used as a support substrate when peeling off the stack including the semiconductor layer 113a, the light-emitting layer 114a, and the semiconductor layer 115a. The adhesive layer 320 has the function of bonding the stack to the substrate 330.

[0087] Alternatively, the stack can be processed in an island or strip shape before the adhesive layer 320 and the substrate 330 are disposed on the semiconductor layer 115a.

[0088] The substrate 330 is preferably a substrate with a flat surface. For example, semiconductor substrates such as silicon, glass substrates, ceramic substrates, metal substrates, resin substrates, etc., can be used.

[0089] As the adhesive layer 320, a material that can be peeled off again after bonding can be used. For example, adhesives, UV-curable resins, thermosetting resins, materials soluble in water or organic solvents, etc., can be used.

[0090] Next, the release layer 310 is etched by wet etching with acid or the like (see Figure 3C), and the substrate 300 is separated (see Figure 3D).

[0091] Next, a stack comprising a semiconductor layer 113a, a light-emitting layer 114a, a semiconductor layer 115a, an adhesive layer 320, and a substrate 330 is fixed onto a separately formed stack comprising layers 11, 12, and 13 (see Figures 4A and 4B). Figures 4A and 4B show the components of layer 13 and illustrate the case where the surface of the semiconductor layer 113a exposed in Figure 3D is fixed to the surface of the insulating layer 102.

[0092] Next, the adhesive layer 320 and the substrate 330 are removed from the stack shown in FIG. 4B (see FIG. 4C). The adhesive layer 320 can be weakened by curing or modifying it, thus weakening its adhesion to the semiconductor layer 115a. Alternatively, the substrate 330 can be removed by dissolving the adhesive layer 320.

[0093] Next, the semiconductor layer 113a, the light-emitting layer 114a, and the semiconductor layer 115a are processed into island shapes to form the semiconductor layer 113, the light-emitting layer 114b, and the semiconductor layer 115b (see Figure 4D).

[0094] Next, in order to form a region that electrically connects the semiconductor layer 113 to the conductive layer 190a, the light-emitting layer 114a and the semiconductor layer 115a are processed, exposing a portion of the surface of the semiconductor layer 113 (see Figure 5A). At this time, a stack of the semiconductor layer 113, the light-emitting layer 114, and the semiconductor layer 115 is formed.

[0095] Next, an insulating layer 103 is formed covering the semiconductor layer 113, the light-emitting layer 114, and the semiconductor layer 115 (see Figure 5B).

[0096] Next, openings leading to semiconductor layer 113 and semiconductor layer 115 are formed in insulating layer 103. In addition, openings leading to conductive layer 189 and conductive layer 192 are formed in insulating layers 103, 102, 187 and 186.

[0097] Next, conductive layers (conductive layer 190a, conductive layer 190c, conductive layer 191a, and conductive layer 191c) are embedded in each of the aforementioned openings. Here, conductive layers 190a and 191a can be used as a pair of electrodes for the light-emitting diode 110. Alternatively, the conductive layers used as a pair of electrodes for the light-emitting diode 110 can be provided in contact with semiconductor layers 113 and 115 respectively, so that one of the conductive layers is electrically connected to conductive layer 190a, and the other of the conductive layers is electrically connected to conductive layer 191a.

[0098] Finally, conductive layers 190b and 191b are formed on the insulating layer 103. Conductive layers 190a and 190c are electrically connected through conductive layer 190b, and conductive layers 191a and 191c are electrically connected through conductive layer 191b (see Figure 5C).

[0099] Note that although the example described above shows the semiconductor layer 113 of the light-emitting diode 110 being fixed to the insulating layer 102 in contact with it, an adhesive layer 500 may also be provided between the insulating layer 102 and the semiconductor layer 113 (see Figure 5D). The adhesive layer 500 can be an insulating resin, a conductive resin (including resins containing conductive fillers), etc. When a conductive resin is used as the adhesive layer 500, the adhesive layer 500 can also be used as an electrode layer in the light-emitting diode 110.

[0100] By performing the above process, a light-emitting diode (LED) can be formed, with one electrode in a pair electrically connected to the conductive layer 189 and the other electrode in the pair electrically connected to the conductive layer 192. Note that although only one LED is shown in the diagram illustrating the above process, multiple LEDs can be formed simultaneously in the process. Furthermore, the above process is just one example; other processes can also be used to form LEDs.

[0101] Although the display device 100A shown in Figures 1, 2A and 2B has a stacked structure of layers 11, 12, 13 and 14, it may also have the stacked structure shown in Figures 6A and 6B.

[0102] Figure 6A is an example of a display device 100B having a stacked structure of layers 15, 12, 13, and 14, which differs from display device 100A in that layer 15 is provided instead of layer 11. Note that the same symbols are used for the same components included in layers 14 and 11.

[0103] Here, layer 15 includes a substrate 152. The substrate 152 serves as a support substrate. The substrate 152 can be, for example, a semiconductor substrate such as silicon, a glass substrate, a ceramic substrate, a metal substrate, a resin substrate, etc. In this structure, the driving circuit of the pixel circuit, etc., can be made of an OS transistor disposed in layer 12. For example, as shown in FIG7A, the transistor 120e included in the driving circuit of the pixel circuit is disposed in the region 402 disposed outside the pixel portion 401.

[0104] The structure of the transistor 120 included in layer 12 is one example; it can also be a transistor 120c with the self-aligned structure shown in FIG. 6C. Alternatively, layer 12 may also include transistors with structures such as interlaced, anti-interlaced, coplanar, and anti-coplanar. The structures of the transistors described above can be used in other display devices shown in this embodiment.

[0105] Furthermore, when the substrate 152 is transmissive to the light emitted by the light-emitting diode 110, as shown in FIG8A, light can be emitted to the outside through the substrate 152 by disposing of the reflective layer 193 on the semiconductor layer 115. Alternatively, as shown in FIG8B, a structure in which light is emitted to both sides can be adopted, omitting the reflective layer 193.

[0106] Figure 6B is an example of a display device 100C having a stacked structure of layers 16, 12, 13, and 14, which differs from display device 100A in that layer 16 is provided instead of layer 11; and layer 12 does not have an OS transistor. Note that the same reference numerals are used for the same components included in layers 16 and 11.

[0107] Here, layer 16 is provided with pixel circuitry (excluding display devices) made of Si transistors. Therefore, layer 16 can be, for example, a semiconductor substrate such as silicon. Figure 6B shows an example of a silicon substrate 153 provided with transistor 130d.

[0108] As shown in FIG. 6D, layer 16 may also have a structure in which a silicon layer is disposed on substrate 154 with an insulating layer 143 in between, and the silicon layer includes a transistor 130f with a self-aligned structure having a channel forming region. As this silicon layer, monocrystalline silicon, polycrystalline silicon, microcrystalline silicon, amorphous silicon, etc., can be used. Alternatively, layer 16 may also include an anti-interlaced type transistor 130g as shown in FIG. 6E. Alternatively, layer 16 may also include a transistor having an interlaced, coplanar, or anti-coplanar structure. The above-described transistor structure can be used in layer 11 included in other display devices shown in this embodiment.

[0109] The substrate 154 can be a silicon substrate, glass substrate, ceramic substrate, metal substrate, resin substrate, etc. The insulating layer 143 is preferably formed by forming a single layer or stack of one or more inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, aluminum oxide, hafnium oxide, and titanium nitride.

[0110] In the display device 100C, the driving circuit of the pixel circuit and the like can be provided in layer 16. For example, as shown in FIG7B, the transistor 130e included in the driving circuit of the pixel circuit is provided in region 402 provided outside the pixel section 401.

[0111] In addition, in display devices 100B and 100C, part or all of the driving circuit of the pixel circuit may be disposed in an external IC chip connected to the pixel circuit.

[0112] Figure 9 shows a cross-sectional view of a display device 100D (also called a touch panel) that combines a display device and a touch sensor. Note that although Figure 9 shows the structure of display device 100A, display device 100B or display device 100C can also be combined with a touch sensor.

[0113] There are no limitations on the sensing devices (also referred to as sensing devices, sensing elements, or sensing components) included in the touch panel of one embodiment of the present invention. Various sensors capable of detecting the proximity or contact of a detection object such as a finger or stylus can also be used as sensing devices.

[0114] For example, various methods can be used as sensors, such as electrostatic capacitive, resistive film, surface acoustic wave, infrared, optical, and pressure-sensitive types.

[0115] In this embodiment, a touch panel including an electrostatic capacitive sensing device will be used as an example for explanation.

[0116] As electrostatic capacitive sensors, there are surface-type electrostatic capacitive sensors and projection-type electrostatic capacitive sensors. Furthermore, projection-type electrostatic capacitive sensors include self-capacitance type and mutual-capacitance type. Mutual-capacitance type is preferred because it allows for simultaneous multi-point sensing.

[0117] The touch panel of one embodiment of the present invention can adopt various structures such as a structure in which a display device and a sensing device are bonded together, or a structure in which electrodes constituting the sensing device are provided on one or both of the substrate supporting the display device and the opposing substrate.

[0118] A conductive layer 194 is disposed on the insulating layer 185. The conductive layer 194 is used as an electrode or wiring to supply power or drive signals to the display device 100A. The conductive layer 194 can be formed using the same material and process as the conductive layer 189, conductive layer 192, reflective layer 193, etc.

[0119] The conductive layer 194 is electrically connected to the FPC (Flexible Printed Circuits) 501 via conductive layers 195, 196, and conductor 197. Power and drive signals can be supplied to the display device 100D via the FPC 501.

[0120] As a conductor 197, for example, anisotropic conductive film (ACF) or anisotropic conductive paste (ACP) can be used.

[0121] A touch sensor is disposed on the first surface of the substrate 171. An adhesive layer 179 is disposed such that it covers the components included in the touch sensor, and the adhesive layer 179 is bonded together with the insulating layer 104.

[0122] A conductive layer 177 and a conductive layer 178 are provided on the first surface of the substrate 171. The conductive layers 177 and 178 are formed on the same plane. The conductive layers 177 and 178 can be made of materials that allow visible light to pass through. An insulating layer 173 is provided to cover the conductive layers 177 and 178. The conductive layer 174 is electrically connected to the two conductive layers 178, which are disposed in a manner that sandwiches the conductive layer 177, through an opening provided in the insulating layer 173.

[0123] Conductive layer 178 is connected to conductive layer 175. Conductive layer 175 can be formed using the same material and process as conductive layer 174. Conductive layer 175 is electrically connected to FPC502 via conductor 176. Similar to conductor 197, anisotropic conductive film or anisotropic conductive paste can be used as conductor 176.

[0124] As described above, the display device of this embodiment can form multiple light-emitting diodes in the same process, and can electrically connect these multiple light-emitting diodes and multiple transistors in the same process. Therefore, it is possible to reduce the manufacturing cost of the display device and improve the yield. In addition, by adopting a structure in which the components such as light-emitting diodes included in the pixel circuit, the transistors included in the pixel circuit, and the components such as transistors included in the driving circuit of the pixel circuit each have overlapping areas, the display device can be miniaturized.

[0125] This embodiment can be appropriately combined with other embodiments. Furthermore, in this specification, where multiple structural examples are shown in one embodiment, these structural examples can be appropriately combined.

[0126] Implementation Method 2 In this embodiment, a structure in which a color conversion layer is provided on the light-emitting side of the light-emitting diode of the display device described in Embodiment 1 will be explained. Note that detailed descriptions of components identical to those in Embodiment 1 are omitted.

[0127] Figure 10 shows a cross-sectional view of the display device 100E. The display device 100E includes a pixel 20R that emits red light, a pixel 20G that emits green light, and a pixel 20B that emits blue light. In addition, a layer 17 is provided on the layer 14 on which the light-emitting diode is disposed. The layer 17 is provided with a color conversion layer, a color layer, and a light-shielding layer, etc.

[0128] Pixel 20R includes a light-emitting diode 110R. Pixel 20G includes a light-emitting diode 110G. Pixel 20B includes a light-emitting diode 110B. Light-emitting diodes 110R, 110G, and 110B all emit light of the same color. In other words, light-emitting diodes 110R, 110G, and 110B can all employ the same structure.

[0129] Specifically, light-emitting diodes 110R, 110G, and 110B preferably all emit blue light. When constructing a color image, pixels emitting the three primary colors of red (R), green (G), and blue (B) light can be used. In the display device described in this embodiment, the pixels use a color conversion layer to convert the light emitted by the light-emitting diodes into light of the desired color before emitting it to the outside. Here, since the pixels emitting blue light do not need to use a color conversion layer when using light-emitting diodes that emit blue light, manufacturing costs can be reduced.

[0130] A color conversion layer 360R and a color layer 361R are provided in the area of ​​the red pixel 20R overlapping the light-emitting diode 110R. The light emitted by the light-emitting diode 110R is converted from blue to red in the color conversion layer 360R, and the purity of the red light is increased in the color layer 361R, and this light is emitted to the outside of the display device 100E. Alternatively, the color layer 361R may be omitted.

[0131] A color conversion layer 360G and a color layer 361G are provided in the area of ​​the green pixel 20G overlapping the light-emitting diode 110G. The light emitted by the light-emitting diode 110G is converted from blue to green in the color conversion layer 360G, and the purity of the green light is increased in the color layer 361G, and this light is emitted to the outside of the display device 100E. Alternatively, the color layer 361G can be omitted.

[0132] A color layer 361B is provided in the area of ​​the blue pixel 20B overlapping the light-emitting diode 110B. The blue light emitted by the light-emitting diode 110B has its purity enhanced in the color layer 361B, and this light is emitted to the outside of the display device 100E. Alternatively, the color layer 361B can be omitted. As described above, the color conversion layer can be omitted in the blue pixel 20B.

[0133] Because only one type of light-emitting diode can be manufactured on the substrate in the display device 100E, the manufacturing equipment and process can be simplified compared to manufacturing multiple types of light-emitting diodes.

[0134] A light-shielding layer 350 is provided between pixels of each color. The light-shielding layer 350 is positioned to at least block the light emitted by the light-emitting diode 110 in the lateral direction. If necessary, it may also be positioned to block the light emitted by the light-emitting diode 110 in the oblique direction. In addition, a light-shielding layer 351 covering the area around the pixels is provided on the insulating layer 104.

[0135] By providing light-shielding layers 350 and 351, light emitted by the light-emitting diode can be suppressed from entering adjacent pixel areas of other colors, thereby preventing color mixing. Therefore, the display quality of the display device can be improved. Alternatively, only one of light-shielding layers 350 and 351 may be provided.

[0136] There are no particular limitations on the materials constituting the light-shielding layer 350 and the light-shielding layer 351. For example, inorganic materials such as metal materials or organic materials such as resin materials containing pigments (such as carbon black) or dyes can be used. In addition, the light-shielding layer 351 can also be formed by layering different colored layers. For example, it can be formed by layering red, green and blue colored layers.

[0137] Furthermore, light-emitting diodes 110R, 110G, and 110B can each emit light with a wavelength whose photon energy is higher than that of blue light. For example, light-emitting diodes capable of emitting blue-violet, violet, or ultraviolet light can be used. By using light with high photon energy, color conversion can be performed efficiently in the color conversion layer.

[0138] In this case, as shown in the display device 100F in FIG11, a color conversion layer 360B and a color layer 361B are provided in the area of ​​the blue pixel 20B overlapping the light-emitting diode 110B. The light emitted by the light-emitting diode 110B is converted from blue-violet, violet or ultraviolet to blue in the color conversion layer 360B, and the purity of the blue light is increased in the color layer 361B, and the light is emitted to the outside of the display device 100E. Alternatively, the color layer 361B may be omitted.

[0139] Phosphors or quantum dots (QDs) are preferred as color conversion layers. In particular, quantum dots have narrow emission spectrum peaks, thus resulting in high color purity light emission. Therefore, the display quality of the display device can be improved.

[0140] Color conversion layers are formed by droplet jetting (e.g., inkjet printing), coating, imprinting, and various printing methods (screen printing, offset printing). Alternatively, color conversion films such as quantum dot films can also be used.

[0141] When processing the film that serves as the color conversion layer, photolithography can be used. For example, a photoresist mask can be formed on the film to be processed, the film can be processed by etching, and then the photoresist mask can be removed. Alternatively, a method can be used to process the film into the desired shape by exposure and development after forming a photosensitive film. For example, an island-shaped color conversion layer can be formed by forming a film using a photosensitive material made of mixed quantum dots and processing the film by photolithography.

[0142] There are no particular limitations on the materials used to construct quantum dots. Examples include elements from Group 14, Group 15, and Group 16; compounds containing multiple elements from Group 14; compounds of elements from Groups 4 to 14 and Group 16; compounds of elements from Groups 2 and 16; compounds of elements from Groups 13 and 15; compounds of elements from Groups 13 and 17; compounds of elements from Groups 14 and 15; compounds of elements from Groups 11 and 17; iron oxides; titanium oxides; spinel; and various semiconductor clusters.

[0143] Specifically, examples include cadmium selenide, cadmium sulfide, cadmium telluride, zinc selenide, zinc oxide, zinc sulfide, zinc telluride, mercuric sulfide, mercuric selenide, mercuric telluride, indium arsenide, indium phosphide, gallium arsenide, gallium phosphide, indium nitride, gallium nitride, indium antimonide, gallium antimonide, aluminum phosphide, aluminum arsenide, aluminum antimonide, lead selenide, lead telluride, lead sulfide, indium selenide, indium telluride, indium sulfide, gallium selenide, arsenic sulfide, arsenic selenide, arsenic telluride, antimony sulfide, antimony selenide, antimony telluride, bismuth sulfide, bismuth selenide, bismuth telluride, silicon, silicon carbide, germanium, tin, selenium, tellurium, boron, carbon, phosphorus, boron nitride, boron phosphide, boron arsenide, aluminum nitride, aluminum sulfide, barium sulfide, barium selenide, barium telluride, calcium sulfide, and selenium. Calcium sulfide, calcium telluride, beryllium sulfide, beryllium selenide, beryllium telluride, magnesium sulfide, magnesium selenide, germanium sulfide, germanium selenide, germanium telluride, tin sulfide, tin selenide, tin telluride, lead oxide, copper fluoride, copper chloride, copper bromide, copper iodide, copper oxide, copper selenide, nickel oxide, cobalt oxide, cobalt sulfide, iron oxide, iron sulfide, manganese oxide, molybdenum sulfide, vanadium oxide, tungsten oxide, tantalum oxide, titanium oxide, zirconium oxide, silicon nitride, germanium nitride, aluminum oxide, barium titanate, compounds of zinc cadmium selenide, zinc cadmium selenide, cadmium arsenide, cadmium selenide, cadmium selenide, tellurium cadmium selenide, indium gallium arsenide, indium gallium selenide, indium selenide, copper indium sulfide, and combinations thereof. In addition, so-called alloy-type quantum dots with compositions expressed in arbitrary ratios can also be used.

[0144] Quantum dots can have various structures, including core-shell, core-multishell, and core-multishell types. Furthermore, due to the high proportion of surface atoms, quantum dots exhibit high reactivity and are prone to aggregation. Therefore, it is preferable that the surface of quantum dots is coated with a protective agent or has protective groups. By attaching a protective agent or providing protective groups, aggregation can be prevented and solubility in solvents can be improved. Additionally, reducing reactivity can enhance electrical stability.

[0145] The smaller the size of a quantum dot, the larger its band gap. Therefore, by appropriately adjusting its size, light of the desired wavelength can be obtained. As the crystal size decreases, the emission of quantum dots shifts towards the blue side (i.e., towards the high-energy side). Therefore, by changing the size of the quantum dots, the emission wavelength can be tuned in a wavelength range covering the ultraviolet, visible, and infrared regions of the spectrum. Commonly used quantum dot sizes (diameters) are, for example, 0.5 nm or more and 20 nm or less, preferably 1 nm or more and 10 nm or less. The smaller the size distribution of quantum dots, the narrower the emission spectrum, thus achieving high color purity emission. Furthermore, there are no particular limitations on the shape of quantum dots; they can be spherical, rod-shaped, disk-shaped, or other shapes. Quantum rods made of rod-shaped quantum dots have the function of directional light emission.

[0146] A color layer is a colored layer that allows light in a specific wavelength range to pass through. For example, color filters that allow light in the red, green, blue, or yellow wavelength range to pass through can be used. Examples of materials that can be used for color layers include metallic materials, resin materials, and resin materials containing pigments or dyes.

[0147] Note that although the structure of display device 100E and display device 100D is shown using the structure of display device 100A, the structure of display device 100E and display device 100D can also be used in other display devices shown in Embodiment 1.

[0148] This embodiment can be appropriately combined with other embodiments. Furthermore, in this specification, where multiple structural examples are shown in one embodiment, these structural examples can be appropriately combined.

[0149] Implementation Method 3 In this embodiment, a transistor of a display device applicable to one embodiment of the present invention is described.

[0150] There are no particular restrictions on the structure of the transistors included in the display device. For example, planar transistors, interleaved transistors, or anti-interleaved transistors can be used. Furthermore, transistors can have either a top-gate or bottom-gate structure. Alternatively, gate electrodes can be provided at the top and bottom of the channel.

[0151] As a transistor included in a display device, a transistor in which metal oxide is used for the channel forming region can be used, for example. Therefore, a transistor with extremely low off-state current can be realized.

[0152] As a transistor included in a display device, a transistor containing silicon in the channel forming region can also be used. Examples of such transistors include transistors containing amorphous silicon, transistors containing crystalline silicon (typically low-temperature polycrystalline silicon), and transistors containing monocrystalline silicon. For example, a transistor using metal oxide in the channel forming region and a transistor containing silicon in the channel forming region can also be used in combination.

[0153] Furthermore, the insulators, conductors, oxides, and semiconductors shown below can be formed by sputtering, chemical vapor deposition (CVD), molecular beam epitaxy (MBE), pulsed laser deposition (PLD), or atomic layer deposition (ALD). Note that in this specification, "insulator" may be replaced with "insulating film" or "insulating layer." Similarly, "conductor" may be replaced with "conductive film" or "conductive layer." "Oxide" may be replaced with "oxide film" or "oxide layer." Finally, "semiconductor" may be replaced with "semiconductor film" or "semiconductor layer."

[0154] Figure 12A is a top view of transistor 200. Note that for clarity, some components are omitted in Figure 12A. Figure 12B is a cross-sectional view along the dashed lines A1-A2 in Figure 12A. Figure 12B can be considered a cross-sectional view along the channel length direction of transistor 200. Figure 12C shows a cross-sectional view along the dashed lines A3-A4 in Figure 12A. Figure 12C can also be considered a cross-sectional view along the channel width direction of transistor 200. Figure 12D is a cross-sectional view along the dashed lines A5-A6 in Figure 12A.

[0155] The semiconductor device shown in Figures 12A to 12D includes an insulator 212 on a substrate (not shown), an insulator 214 on the insulator 212, a transistor 200 on the insulator 214, an insulator 280 on the transistor 200, an insulator 282 on the insulator 280, an insulator 283 on the insulator 282, and an insulator 285 on the insulator 283. Insulators 212, 214, 280, 282, 283, and 285 are used as interlayer insulating films. Additionally, it includes conductors 240 (conductors 240a and 240b) that are electrically connected to the transistor 200 and serve as a connector. Furthermore, insulators 241 (insulators 241a and 241b) are provided in contact with the sides of the conductors 240 used as connectors. Additionally, conductors 246 (conductor 246a and conductor 246b) are provided on insulator 285 and conductor 240, respectively, and are electrically connected to conductor 240 and used for wiring.

[0156] An insulator 241a is disposed in contact with the inner wall of the openings of insulators 280, 282, 283, and 285. A first conductor 240a is disposed in contact with the side of insulator 241a, and a second conductor 240a is disposed inside the first conductor 240a. Similarly, an insulator 241b is disposed in contact with the inner wall of the openings of insulators 280, 282, 283, and 285. A first conductor 240b is disposed in contact with the side of insulator 241b, and a second conductor 240b is disposed inside the first conductor 240b. Here, the height of the top surface of the conductor 240 can be approximately the same as the height of the top surface of the insulator 285 overlapping the region of the conductor 246. Furthermore, a structure is shown in which the first conductor and the second conductor are stacked as conductor 240 in the transistor 200, but the present invention is not limited thereto. For example, the conductor 240 may also have a single-layer structure or a stacked structure of three or more layers. In addition, when the structure has a stacked structure, ordinal numbers are sometimes assigned according to the order of formation for distinction.

[0157] [Transistor 200] As shown in Figures 12A to 12D, the transistor 200 includes an insulator 216 on an insulator 214, conductors 205 (conductors 205a and 205b) disposed in the insulator 216, an insulator 222 on the insulator 216 and on the conductors 205, an insulator 224 on the insulator 222, an oxide 230a on the insulator 224, an oxide 230b on the oxide 230a, an oxide 243 (oxides 243a and 243b) on the oxide 230b, a conductor 242a on the oxide 243a, and an insulator 27 on the conductor 242a. 1a. Conductor 242b on oxide 243b, insulator 271b on conductor 242b, insulator 250 (insulator 250a and insulator 250b) on oxide 230b, conductor 260 (conductor 260a and conductor 260b) located on insulator 250 and overlapping a portion of oxide 230b, and insulator 275 configured to cover insulator 222, insulator 224, oxide 230a, oxide 230b, oxide 243a, oxide 243b, conductor 242a, conductor 242b, insulator 271a and insulator 271b.

[0158] Hereinafter, oxides 230a and 230b are sometimes collectively referred to as oxide 230. Additionally, conductors 242a and 242b are sometimes collectively referred to as conductor 242. Furthermore, insulators 271a and 271b are sometimes collectively referred to as insulator 271.

[0159] An opening reaching the oxide 230b is formed in insulators 280 and 275. An insulator 250 and a conductor 260 are disposed within this opening. Furthermore, along the channel length direction of the transistor 200, a conductor 260 and an insulator 250 are disposed between insulators 271a, 242a, and 243a and insulators 271b, 242b, and 243b. The insulator 250 has a region that contacts the side surface of the conductor 260 and a region that contacts the bottom surface of the conductor 260.

[0160] Oxide 230 preferably includes oxide 230a on insulator 224 and oxide 230b on oxide 230a. When oxide 230a is included below oxide 230b, the diffusion of impurities from the structure formed below oxide 230a to oxide 230b can be suppressed.

[0161] Note that in transistor 200, oxide 230 has a two-layer stacked structure of oxide 230a and oxide 230b, but the present invention is not limited thereto. For example, oxide 230 may have a single-layer or three-layer stacked structure of oxide 230b, or it may have a structure in which oxide 230a and oxide 230b are stacked separately.

[0162] Conductor 260 is used as the first gate (also called the top gate) electrode, and conductor 205 is used as the second gate (also called the back gate) electrode. Furthermore, insulator 250 is used as the first gate insulating film, and insulators 224 and 222 are used as the second gate insulating films. Additionally, conductor 242a is used as one of the source electrode and the drain electrode, and conductor 242b is used as the other of the source electrode and the drain electrode. Furthermore, at least a portion of the region of oxide 230 overlapping with conductor 260 is used as a channel forming region.

[0163] Oxide 230b has one of a source region and a drain region in the region overlapping with conductor 242a, and the other of a source region and a drain region in the region overlapping with conductor 242b. In addition, oxide 230b has a channel forming region in the region sandwiched between the source region and the drain region (the region shown in shaded area in FIG12B).

[0164] The channel-forming region is a high-resistivity region with fewer oxygen vacancies or lower impurity concentrations and carrier concentrations compared to the source and drain regions. Here, the carrier concentration in the channel-forming region is preferably below 1 × 10¹⁸ cm⁻³, more preferably below 1 × 10¹⁷ cm⁻³, further preferably below 1 × 10¹⁶ cm⁻³, even more preferably below 1 × 10¹³ cm⁻³, and still more preferably below 1 × 10¹² cm⁻³. Note that there is no particular limitation on the lower limit of the carrier concentration in the channel-forming region; for example, it can be 1 × 10⁻⁹ cm⁻³.

[0165] Note that the above shows an example of forming a channel region, a source region, and a drain region in oxide 230b, but the present invention is not limited thereto. For example, sometimes a channel region, a source region, and a drain region are also formed in oxide 230a in the same way.

[0166] Alternatively, it is preferable that the metal oxide (also known as oxide semiconductor) to be used as a semiconductor in the transistor 200 is used in the oxide 230 (oxide 230a and oxide 230b) containing the channel forming region.

[0167] Furthermore, the band gap of the metal oxide used as a semiconductor is preferably 2 eV or higher, and more preferably 2.5 eV or higher. In this way, by using a metal oxide with a wider band gap, the off-state current of the transistor can be reduced.

[0168] As oxide 230, it is preferably an In-M-Zn oxide containing indium, element M, and zinc (element M is selected from one or more of aluminum, gallium, yttrium, tin, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium). Alternatively, In-Ga oxide, In-Zn oxide, and indium oxide can also be used as oxide 230.

[0169] Preferably, the ratio of the number of In atoms to the number of element M in the metal oxide used for oxide 230b is greater than the ratio of the number of In atoms to the number of element M in the metal oxide used for oxide 230a.

[0170] Specifically, for oxide 230a, a metal oxide with an In:M:Zn ratio of 1:3:4 or similar, or an In:M:Zn ratio of 1:1:0.5 or similar, is acceptable. For oxide 230b, a metal oxide with an In:M:Zn ratio of 1:1:1 or similar, or an In:M:Zn ratio of 4:2:3 or similar, is acceptable. Note that "similar" includes a range of ±30% of the desired atomic ratio. Furthermore, gallium is preferably used as element M.

[0171] Furthermore, when forming metal oxides by sputtering, the aforementioned atomic ratio is not limited to the atomic ratio of the formed metal oxide, but can also be the atomic ratio of the sputtering target used to form the metal oxide.

[0172] Thus, by placing oxide 230a below oxide 230b, the diffusion of impurities and oxygen from the structure formed below oxide 230a to oxide 230b can be suppressed.

[0173] Furthermore, oxides 230a and 230b contain a common element (as a major component) besides oxygen, which can reduce the defect state density at each interface of oxides 230a and 230b. Because the defect state density at the interface of oxides 230a and 230b can be reduced, the influence of interface scattering on carrier conduction is small, thus resulting in a large on-state current.

[0174] Oxide 230b is preferably crystalline. In particular, it is preferred to use CAAC-OS (c-axis aligned crystalline oxide semiconductor) as oxide 230b.

[0175] CAAC-OS possesses a highly crystalline, dense structure and is a metal oxide with few impurities and defects (e.g., oxygen vacancies). In particular, by heat-treating CAAC-OS after its formation at a temperature that prevents polymorphism (e.g., above 400°C and below 600°C), a more crystalline, dense structure can be achieved. Thus, by further increasing the density of CAAC-OS, the diffusion of impurities or oxygen within it can be further reduced.

[0176] On the other hand, distinct grain boundaries are not easily observed in CAAC-OS, thus reducing the likelihood of a decrease in electron mobility due to grain boundaries. Therefore, metal oxides containing CAAC-OS exhibit stable physical properties. Consequently, metal oxides with CAAC-OS possess heat resistance and high reliability.

[0177] At least one of insulators 212, 214, 271, 275, 282, and 283 is preferably used as a barrier insulating film to inhibit the diffusion of impurities such as water and hydrogen from one side of the substrate or above the transistor 200 to the transistor 200. Therefore, at least one of insulators 212, 214, 271, 275, 282, and 283 is preferably an insulating material that has the function of inhibiting the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (N2O, NO, NO2, etc.), and copper atoms (making it difficult for the aforementioned impurities to permeate). Furthermore, it is preferable to use an insulating material that has the function of inhibiting the diffusion of oxygen (e.g., at least one of oxygen atoms and oxygen molecules, making it difficult for the aforementioned oxygen to permeate).

[0178] In addition, in this specification, "barrier insulating film" refers to an insulating film with barrier properties. Note that in this specification, barrier properties mean the ability to inhibit the diffusion of the corresponding substance (also known as low permeability). Alternatively, barrier properties mean the ability to trap and fix the corresponding substance (also known as gettering).

[0179] As insulators 212, 214, 271, 275, 282, and 283, materials such as aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride can be used. For example, silicon nitride, which has higher hydrogen blocking properties, is preferred as insulators 212, 275, and 283. Furthermore, aluminum oxide or magnesium oxide, which have high hydrogen trapping and fixing properties, is preferred as insulators 214, 271, and 282. Therefore, the diffusion of impurities such as water and hydrogen from the substrate side to the transistor 200 side via insulators 212 and 214 can be suppressed. Furthermore, the diffusion of impurities such as water and hydrogen from the interlayer insulating film disposed outside insulator 283 to the transistor 200 side can be suppressed. Additionally, the diffusion of oxygen in insulator 224 to the substrate side via insulators 212 and 214 can be suppressed. In addition, it can suppress the diffusion of oxygen from insulator 280 to the top of transistor 200 via insulator 282. Thus, it is preferable to adopt a structure in which insulator 212, insulator 214, insulator 271, insulator 275, insulator 282 and insulator 283 surround transistor 200, which have the function of suppressing the diffusion of impurities such as water and hydrogen and oxygen.

[0180] Here, insulators 212, 214, 271, 275, 282, and 283 are preferably insulators with an amorphous structure. For example, metal oxides such as AlOx (where x is any number greater than 0) or MgOy (where y is any number greater than 0) are preferred. These amorphous metal oxides have the property that oxygen atoms have dangling bonds, which sometimes trap or fix hydrogen. By using these amorphous metal oxides as components of the transistor 200 or placing them around the transistor 200, hydrogen contained in the transistor 200 or present around the transistor 200 can be trapped or fixed. In particular, it is preferable to trap or fix hydrogen contained in the channel-forming region of the transistor 200. By using amorphous metal oxides as components of the transistor 200 or placing them around the transistor 200, a highly reliable transistor 200 and semiconductor device with good characteristics can be manufactured.

[0181] Furthermore, insulators 212, 214, 271, 275, 282, and 283 are preferably amorphous, but polycrystalline regions may also be formed in some of them. Additionally, insulators 212, 214, 271, 275, 282, and 283 may also have a multilayer structure with layers of amorphous and polycrystalline structures stacked on top of each other. For example, a stacked structure in which polycrystalline layers are stacked on top of amorphous layers may also be present.

[0182] Films of insulators 212, 214, 271, 275, 282, and 283 can be formed, for example, by sputtering. Sputtering eliminates the need for hydrogen as the deposition gas, thus reducing the hydrogen concentration in insulators 212, 214, 271, 275, 282, and 283. Note that the film formation method is not limited to sputtering; CVD, MBE, PLD, ALD, and other methods can also be appropriately used.

[0183] Furthermore, the dielectric constants of insulators 216, 280, and 285 are preferably lower than those of insulator 214. By using materials with low dielectric constants in the interlayer insulating film, parasitic capacitances generated between wirings can be reduced. For example, silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, fluorine-added silicon oxide, carbon-added silicon oxide, silicon oxide with carbon and nitrogen added, or porous silicon oxide are appropriately used as insulators 216, 280, and 285.

[0184] The conductor 205 is arranged to overlap with the oxide 230 and the conductor 260. Preferably, the conductor 205 is embedded in an opening in the insulator 216.

[0185] The conductor 205 includes conductor 205a and conductor 205b. Conductor 205a is in contact with the bottom surface and sidewalls of the opening. Conductor 205b is disposed in a recess formed in conductor 205a. Here, the height of the top surface of conductor 205b is approximately the same as the height of the top surface of conductor 205a and the height of the top surface of insulator 216.

[0186] Conductor 205a can be made of the conductive material described later for conductor 260a. Similarly, conductor 205b can be made of the conductive material described later for conductor 260b. Note that the diagram shows a structure in transistor 200 in which conductors 205a and 205b are stacked, but the invention is not limited to this. For example, conductor 205 can have a single-layer structure, or it can have a stacked structure of two or more layers.

[0187] Insulators 222 and 224 are used as gate insulating films.

[0188] Insulator 222 preferably has the function of suppressing the diffusion of hydrogen (e.g., at least one of hydrogen atoms, hydrogen molecules, etc.). Furthermore, insulator 222 preferably has the function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms, oxygen molecules, etc.). For example, insulator 222 preferably has the function of suppressing the diffusion of hydrogen and / or oxygen compared to insulator 224.

[0189] The insulator 222 is preferably an insulator containing an oxide of one or both of aluminum and hafnium as insulating materials. Preferably, the insulator is aluminum oxide, hafnium oxide, or an oxide containing aluminum and hafnium (hafnium aluminate). Alternatively, a barrier insulating film suitable for use in the aforementioned insulator 214 can also be used as the insulator 222.

[0190] Silicon oxide or silicon oxynitride can be appropriately used as the insulator 224. By providing the oxygen-containing insulator 224 in contact with the oxide 230, oxygen vacancies in the oxide 230 can be reduced, thereby improving the reliability of the transistor 200. Furthermore, the insulator 224 is preferably processed into an island shape, overlapping with the oxide 230a. In this case, the insulator 275 contacts the side surface of the insulator 224 and the top surface of the insulator 222. Thus, the insulator 275 can separate the insulator 224 from the insulator 280, thereby suppressing the diffusion of oxygen from the insulator 280 into the insulator 224 and preventing excessive oxygen in the insulator 224.

[0191] Furthermore, insulators 222 and 224 can also have a stacked structure of two or more layers. In this case, it is not limited to a stacked structure made of the same material; it can also be a stacked structure formed using different materials. Note that Figure 12B, etc., shows an island-like structure in which insulator 224 is formed by overlapping oxide 230a, but the present invention is not limited to this. As long as the oxygen content in insulator 224 can be adjusted to a suitable amount, insulator 224 can be left unpatterned, just like insulator 222.

[0192] Oxides 243a and 243b are disposed on oxide 230b. Oxides 243a and 243b are separated by conductor 260. Oxides 243 (oxides 243a and 243b) preferably have the function of suppressing oxygen permeation. By disposing oxide 243, which has the function of suppressing oxygen permeation, between conductor 242, which is used as a source electrode or drain electrode, and oxide 230b, the resistance between conductor 242 and oxide 230b is reduced, which is preferable. Alternatively, oxide 243 may not be disposed if the resistance between conductor 242 and oxide 230b can be sufficiently reduced.

[0193] Metal oxides containing element M can also be used as oxide 243. In particular, aluminum, gallium, yttrium, or tin are preferably used as element M. The concentration of element M in oxide 243 is preferably higher than that in oxide 230b. Furthermore, gallium oxide can also be used as oxide 243. In addition, metal oxides such as In-M-Zn oxide can also be used as oxide 243. Specifically, the number of atoms of element M relative to In in the metal oxide used for oxide 243 is preferably greater than the ratio of the number of atoms of element M relative to In in the metal oxide used for oxide 230b. Furthermore, the film thickness of oxide 243 is preferably 0.5 nm or more and 5 nm or less, more preferably 1 nm or more and 3 nm or less, and even more preferably 1 nm or more and 2 nm or less.

[0194] Preferably, conductor 242a is in contact with the top surface of oxide 243a, and conductor 242b is in contact with the top surface of oxide 243b. Conductors 242a and 242b are used as the source electrode or drain electrode of transistor 200, respectively.

[0195] As conductors 242 (conductors 242a and 242b), it is preferred to use nitrides containing tantalum, nitrides containing titanium, nitrides containing molybdenum, nitrides containing tungsten, nitrides containing tantalum and aluminum, nitrides containing titanium and aluminum, etc. In one embodiment of the invention, it is particularly preferred to use nitrides containing tantalum. In addition, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, oxides containing lanthanum and nickel, etc., may also be used. These materials are preferred because they are conductive materials that are not easily oxidized or maintain conductivity even when absorbing oxygen.

[0196] Furthermore, it is preferable that no curved surface is formed between the side surface and the top surface of the conductor 242. By eliminating this curved surface, the cross-sectional area of ​​the conductor 242 in the channel width direction, as shown in FIG12D, can be increased. This improves the conductivity of the conductor 242 and thus increases the on-state current of the transistor 200.

[0197] The top surface of insulator 271a is in contact with the top surface of conductor 242a, and the top surface of insulator 271b is in contact with the top surface of conductor 242b.

[0198] The insulator 275 is disposed in contact with the top surface of the insulator 222, the side surface of the insulator 224, the side surface of the oxide 230a, the side surface of the oxide 230b, the side surface of the oxide 243, the side surface of the conductor 242, and the side surface and top surface of the insulator 271. An opening is formed in the insulator 275 in the area where the insulator 250 and the conductor 260 are disposed.

[0199] By providing insulators 214, 271, and 275, which have the function of trapping impurities such as hydrogen, in the region sandwiched between insulator 212 and insulator 275, impurities such as hydrogen in insulators 224 or 216 can be trapped, thereby ensuring that the amount of hydrogen in that region is constant. In this case, insulators 214, 271, and 275 are preferably aluminum oxide containing an amorphous structure.

[0200] The insulator 250 includes an insulator 250a and an insulator 250b on the insulator 250a and is used as a gate insulating film. Preferably, the insulator 250a is arranged in contact with the top surface of the oxide 230b, the side surface of the oxide 243, the side surface of the conductor 242, the side surface of the insulator 271, the side surface of the insulator 275, and the side surface of the insulator 280. Preferably, the film thickness of the insulator 250 is 1 nm or more and 20 nm or less.

[0201] Silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen, and porous silicon oxide can be used as insulator 250a. In particular, silicon oxide and silicon oxynitride have thermal stability, so they are preferred. Similar to insulator 224, it is preferable that the concentration of impurities such as water or hydrogen in insulator 250a is reduced.

[0202] Note that, preferably, insulator 250a is formed using an insulator that releases oxygen upon heating, and insulator 250b is formed using an insulator that has the function of suppressing oxygen diffusion. By having the above structure, the diffusion of oxygen contained in insulator 250a to conductor 260 can be suppressed. In other words, the reduction in the amount of oxygen supplied to oxide 230 can be suppressed. Furthermore, oxidation of conductor 260 caused by oxygen contained in insulator 250a can be suppressed. For example, insulator 250b can be made of the same material as insulator 222.

[0203] Specifically, the insulator 250b can be one or more metal oxides selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, magnesium, etc., or a metal oxide that can be used for oxide 230. In particular, it is preferred to use an insulator containing an oxide of one or both of aluminum and hafnium. As this insulator, aluminum oxide, hafnium oxide, oxides containing aluminum and hafnium (hafnium aluminate), etc., are preferred. In addition, the film thickness of the insulator 250b is preferably 0.5 nm or more and 3.0 nm or less, more preferably 1.0 nm or more and 1.5 nm or less.

[0204] Note that Figures 12B and 12C show an insulator 250 with a two-layer stacked structure, but the invention is not limited thereto. The insulator 250 may also be a single layer or have a stacked structure with three or more layers.

[0205] Conductor 260 is disposed on insulator 250b and serves as the first gate electrode of transistor 200. Conductor 260 preferably includes conductor 260a and conductor 260b disposed on conductor 260a. For example, conductor 260a is preferably disposed such that it surrounds the bottom and side surfaces of conductor 260b. Furthermore, as shown in Figures 12B and 12C, the top surface of conductor 260 is substantially aligned with the top surface of insulator 250. Although conductor 260 has a two-layer structure of conductor 260a and conductor 260b in Figures 12B and 12C, it may also have a single-layer structure or a stacked structure of three or more layers.

[0206] As the conductor 260a, it is preferable to use a conductive material that has the function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules, and copper atoms. Furthermore, it is preferable to use a conductive material that has the function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms and oxygen molecules).

[0207] Furthermore, when the conductor 260a has the function of inhibiting oxygen diffusion, it can prevent the oxygen contained in the insulator 250 from oxidizing the conductor 260b and causing a decrease in conductivity. For example, titanium, titanium nitride, tantalum, tantalum nitride, ruthenium, and ruthenium oxide can be used as conductive materials with the function of inhibiting oxygen diffusion.

[0208] Furthermore, since conductor 260 is also used for wiring, it is preferable to use a conductor with high conductivity. For example, conductor 260b can be a conductive material with tungsten, copper, or aluminum as the main component. In addition, conductor 260b can have a laminated structure, for example, it can have a laminated structure of titanium or titanium nitride with the aforementioned conductive material.

[0209] Furthermore, in the transistor 200, the conductor 260 is formed in a self-aligned manner by filling the openings formed in the insulator 280, etc. By forming the conductor 260 in this way, the conductor 260 can be reliably disposed in the region between the conductor 242a and the conductor 242b without alignment.

[0210] Furthermore, as shown in Figure 12C, in the channel width direction of the transistor 200, with the bottom surface of the insulator 222 as a reference, the height of the bottom surface of the region of the conductor 260 that does not overlap with the oxide 230b is preferably lower than the height of the bottom surface of the oxide 230b. By employing a structure in which the conductor 260, which serves as the gate electrode, covers the side and top surfaces of the channel forming region of the oxide 230b via the insulator 250, it is easier for the electric field of the conductor 260 to act on the entire channel forming region of the oxide 230b. This improves the on-state current and frequency characteristics of the transistor 200. With the bottom surface of the insulator 222 as a reference, the difference between the height of the bottom surface of the conductor 260 and the bottom surface of the oxide 230b in the region where the oxides 230a and 230b do not overlap with the conductor 260 is 0 nm or more and 100 nm or less, preferably 3 nm or more and 50 nm or less, and more preferably 5 nm or more and 20 nm or less.

[0211] An insulator 280 is disposed on an insulator 275, and an opening is formed in the region where the insulator 250 and the conductor 260 are disposed. Furthermore, the top surface of the insulator 280 may be planarized. In this case, the height of the top surface of the insulator 280 is preferably approximately the same as the height of the top surface of the insulator 250 and the top surface of the conductor 260.

[0212] The insulator 282 is disposed in contact with the top surface of the insulator 280, the top surface of the insulator 250, and the top surface of the conductor 260. Preferably, the insulator 282 serves as a barrier insulating film that inhibits the diffusion of impurities such as water and hydrogen from above into the insulator 280 and also has the function of capturing impurities such as hydrogen. Preferably, the insulator 282 also serves as a barrier insulating film that inhibits oxygen permeation. For example, an insulator such as alumina can be used as the insulator 282. By disposing of the insulator 282, which is in contact with the insulator 280 and has the function of capturing impurities such as hydrogen, in the region sandwiched between the insulator 212 and the insulator 283, impurities such as hydrogen contained in the insulator 280 can be captured, and the amount of hydrogen in that region can be kept constant. In particular, using alumina with an amorphous structure or alumina composed of an amorphous structure as the insulator 282 can sometimes further effectively capture or fix hydrogen, which is preferable. Therefore, a transistor 200 and a semiconductor device with good characteristics and high reliability can be manufactured.

[0213] Conductors 240a and 240b are preferably made of conductive materials with tungsten, copper, or aluminum as the main components. Furthermore, conductors 240a and 240b may also have a laminated structure. When conductor 240 adopts a laminated structure, the conductor in contact with insulator 241 is preferably made of a conductive material that suppresses the permeation of impurities such as water and hydrogen. For example, the conductive material described above that can be used in conductor 260a can be used.

[0214] For example, silicon nitride, aluminum oxide, or silicon oxynitride can be used as insulators 241a and 241b. Because insulators 241a and 241b are disposed in contact with insulators 283, 282, and 271, impurities such as water and hydrogen contained in insulators 280 can be suppressed from being mixed into oxide 230 through conductors 240a and 240b.

[0215] Conductors 246 (conductors 246a and 246b) used for wiring can be configured to contact the top surfaces of conductors 240a and 240b. Conductors 246 are preferably made of conductive materials primarily composed of tungsten, copper, or aluminum. Furthermore, the conductor can have a laminated structure, for example, a laminated structure of titanium or titanium nitride with the aforementioned conductive material. Additionally, the conductor can be embedded in an opening in an insulator.

[0216] Therefore, a semiconductor device with good electrical characteristics can be provided. Furthermore, a semiconductor device with high reliability can be provided. Additionally, a semiconductor device that can be miniaturized or highly integrated can be provided. Furthermore, a semiconductor device with low power consumption can be provided.

[0217] [Metal Oxides] Next, metal oxides (also known as oxide semiconductors) that can be used as transistors will be explained.

[0218] The metal oxide preferably contains at least indium or zinc. More preferably, it contains both indium and zinc. Additionally, it preferably also contains aluminum, gallium, yttrium, or tin. Furthermore, it may contain one or more elements selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, and cobalt.

[0219] In addition, metal oxides can be formed by CVD methods such as sputtering, metal-organic chemical vapor deposition (MOCVD), or ALD methods.

[0220] <Classification of Crystal Structures> Examples of crystalline structures for oxide semiconductors include amorphous (including completely amorphous), CAAC (c-axis-aligned crystalline), nc (nanocrystalline), CAC (cloud-aligned composite), single crystal, and polycrystalline.

[0221] The crystal structure of a film or substrate can be evaluated using X-ray diffraction (XRD) spectroscopy. For example, the XRD spectrum obtained by GIXD (Grazing-Incidence XRD) can be used for evaluation. GIXD is also known as the thin film method or the Seemann-Bohlin method.

[0222] For example, the peak shapes of the XRD spectrum of a quartz glass substrate are roughly symmetrical. On the other hand, the peak shapes of the XRD spectrum of an IGZO film with a crystalline structure are asymmetrical. The asymmetry of the XRD peak shapes indicates the presence of crystals in the film or substrate. In other words, unless the XRD peak shapes are symmetrical, it cannot be said that the film or substrate is in an amorphous state.

[0223] Furthermore, the crystal structure of the film or substrate can be evaluated using diffraction patterns observed by nano-beam electron diffraction (NBED). For example, observing a halo pattern in the diffraction pattern of a quartz glass substrate confirms that the quartz glass is in an amorphous state. Conversely, observing a spot-like pattern without a halo in the diffraction pattern of an IGZO film formed at room temperature suggests that the IGZO film formed at room temperature is in an intermediate state, neither crystalline nor amorphous, and therefore cannot be classified as amorphous.

[0224] <<Structure of Oxide Semiconductors>> Furthermore, when considering crystal structure, oxide semiconductors sometimes belong to a different category than those described above. For example, oxide semiconductors can be classified into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include CAAC-OS and nc-OS, as mentioned above. In addition, non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, a-like OS (amorphous-like oxide semiconductor), and amorphous oxide semiconductors.

[0225] Here, we will explain the details of CAAC-OS, nc-OS, and a-like OS.

[0226] [[CAAC-OS]] CAAC-OS is an oxide semiconductor comprising multiple crystalline regions, whose c-axis is aligned in a specific direction. This specific direction refers to the thickness direction of the CAAC-OS film, the normal direction of the formed surface of the CAAC-OS film, or the normal direction of the surface of the CAAC-OS film. Furthermore, a crystalline region is a region exhibiting a periodic atomic arrangement. Note that when atomic arrangement is considered as lattice arrangement, a crystalline region is also a region with a consistent lattice arrangement. Moreover, CAAC-OS has regions where multiple crystalline regions are connected along the ab-plane direction, and sometimes these regions exhibit distortion. Distortion refers to the portion of the lattice arrangement direction that changes between regions with consistent lattice arrangement and other regions with consistent lattice arrangement within the region where multiple crystalline regions are connected. In other words, CAAC-OS refers to an oxide semiconductor with c-axis alignment but no obvious alignment along the ab-plane direction.

[0227] Furthermore, each of the aforementioned multiple crystalline regions is composed of one or more microcrystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of a single microcrystal, the maximum diameter of that region is less than 10 nm. Conversely, when a crystalline region is composed of multiple microcrystals, the size of that region can sometimes be around tens of nm.

[0228] Furthermore, in In-M-Zn oxides (where element M is selected from one or more of aluminum, gallium, yttrium, tin, and titanium), CAAC-OS tends to have a layered crystal structure (also called a layered structure) comprising layers containing stacked indium (In) and oxygen (hereinafter, In layer) and layers containing element M, zinc (Zn), and oxygen (hereinafter, (M,Zn) layer). In addition, indium and element M can substitute for each other. Therefore, sometimes the (M,Zn) layer contains indium. Also, sometimes the In layer contains element M. Note that sometimes the In layer contains Zn. This layered structure is observed, for example, as a lattice image in high-resolution TEM (Transmission Electron Microscope) images.

[0229] For example, when performing structural analysis on CAAC-OS films using an XRD apparatus, the peak value of the c-axis alignment is detected at or near 2θ = 31° in out-of-plane XRD measurements using θ / 2θ scanning. Note that the position (2θ value) representing the peak value of the c-axis alignment sometimes varies depending on the type and composition of the metallic elements constituting CAAC-OS.

[0230] Additionally, for example, multiple bright spots (spots) were observed in the electron diffraction pattern of the CAAC-OS film. Furthermore, when the spot of the incident electron beam passing through the sample (also known as the direct spot) is taken as the center of symmetry, one spot and other spots are observed at point-symmetrical positions.

[0231] When observing the crystalline region from the aforementioned specific directions, although the lattice arrangement in this region is basically hexagonal, the unit lattice is not limited to a regular hexagon; there are also cases where it is non-regular hexagonal. Furthermore, in the aforementioned distortions, pentagonal, heptagonal, and other lattice arrangements are sometimes observed. Additionally, no clear grain boundary is observed near the distortion of CAAC-OS. That is, the distortion of the lattice arrangement inhibits the formation of grain boundaries. This may be because CAAC-OS can tolerate distortions caused by reasons such as a low density of oxygen atoms in the ab-plane direction or changes in the bonding distance between atoms due to the substitution of metal atoms.

[0232] Furthermore, a crystalline structure with clearly defined grain boundaries is called polycrystalline. Grain boundaries act as recombination centers, trapping carriers and potentially leading to a decrease in the transistor's on-state current and field-effect mobility. Therefore, CAAC-OS, which lacks clearly defined grain boundaries, is one of the crystalline oxides that provides an excellent crystalline structure for the semiconductor layer of the transistor. Note that a Zn-containing structure is preferred for constructing CAAC-OS. For example, In-Zn oxides and In-Ga-Zn oxides are preferred because they can further suppress grain boundary formation compared to In oxides.

[0233] CAAC-OS is an oxide semiconductor with high crystallinity and no clearly defined grain boundaries. Therefore, it can be said that in CAAC-OS, the reduction in electron mobility due to grain boundaries is less likely to occur. Furthermore, the crystallinity of oxide semiconductors can sometimes decrease due to the incorporation of impurities and the formation of defects; therefore, CAAC-OS can be considered an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Thus, oxide semiconductors containing CAAC-OS exhibit stable physical properties. Consequently, oxide semiconductors containing CAAC-OS possess high heat resistance and high reliability. In addition, CAAC-OS is stable against high temperatures (so-called thermal budget) in the manufacturing process. Therefore, by using CAAC-OS in OS transistors, process flexibility can be increased.

[0234] [[nc-OS]] In nc-OS, the atomic arrangement in tiny regions (e.g., regions larger than 1 nm and smaller than 10 nm, particularly regions larger than 1 nm and smaller than 3 nm) exhibits periodicity. In other words, nc-OS possesses tiny crystallinity. Furthermore, for example, these tiny crystallinity sizes are between 1 nm and 10 nm, particularly between 1 nm and 3 nm; these tiny crystallinity sizes are referred to as nanocrystals. Additionally, no regularity in crystallization orientation is observed between different nanocrystals in nc-OS. Therefore, no alignment is observed in the overall film. Thus, sometimes nc-OS is indistinguishable from a-like OS or amorphous oxide semiconductors in certain analytical methods. For example, when performing structural analysis on nc-OS films using an XRD apparatus, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Furthermore, when performing electron diffraction (also known as selected area electron diffraction) on nc-OS films using electron beams with a beam diameter larger than that of nanocrystals (e.g., larger than 50 nm), a diffraction pattern resembling a halo pattern is observed. On the other hand, when electron diffraction (also known as nano-beam electron ray) is performed on nc-OS films using electron beams whose beam diameter is close to or smaller than the size of nanocrystals (e.g., above 1 nm and below 30 nm), electron diffraction patterns of multiple spots are sometimes observed in an annular region centered on a direct spot.

[0235] [[a-like OS]] a-like OS is an oxide semiconductor with a structure intermediate between nc-OS and amorphous oxide semiconductors. a-like OS contains voids or low-density regions. That is, a-like OS has lower crystallinity than nc-OS and CAAC-OS. Furthermore, the hydrogen concentration in a-like OS films is higher than that in nc-OS and CAAC-OS films.

[0236] <<Structure of Oxide Semiconductors>> Next, the details of CAC-OS will be explained. Note that CAC-OS is related to the material composition.

[0237] [[CAC-OS]] CAC-OS, for example, refers to a composition in which elements are non-uniformly distributed within a metal oxide, wherein the size of the material containing the non-uniformly distributed elements is 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 3 nm or approximately. Note that, below, the state in which one or more metal elements are non-uniformly distributed within a metal oxide and the regions containing those metal elements are mixed is also referred to as mosaic or patch-like, wherein the size of the region is 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 3 nm or approximately.

[0238] Furthermore, CAC-OS refers to a structure in which the material is divided into a first region and a second region, forming a mosaic-like structure, with the first region distributed throughout the film (hereinafter also referred to as cloud-like). In other words, CAC-OS refers to a composite metal oxide having a structure that combines the first and second regions.

[0239] Here, each of the atomic ratios of In, Ga, and Zn, the metal elements constituting the CAC-OS in the In-Ga-Zn oxide, is denoted as [In], [Ga], and [Zn]. For example, in the CAC-OS of the In-Ga-Zn oxide, a first region is a region where [In] is greater than [In] in the composition of the CAC-OS film. A second region is a region where [Ga] is greater than [Ga] in the composition of the CAC-OS film. Alternatively, for example, a first region is a region where [In] is greater than [In] in the second region and [Ga] is less than [Ga] in the second region. A second region is a region where [Ga] is greater than [Ga] in the first region and [In] is less than [In] in the first region.

[0240] Specifically, the first region mentioned above is a region whose main component is indium oxide or indium zinc oxide. Furthermore, the second region mentioned above is a region whose main component is gallium oxide or gallium zinc oxide. In other words, the first region can be referred to as a region whose main component is In. The second region can be referred to as a region whose main component is Ga.

[0241] Note that sometimes the clear boundaries between the first region and the second region mentioned above are not observable.

[0242] Furthermore, CAC-OS in In-Ga-Zn oxides refers to a structure in which regions dominated by Ga and regions dominated by In are irregularly arranged in a mosaic pattern within a material containing In, Ga, Zn, and O. Therefore, it can be inferred that CAC-OS has a structure with unevenly distributed metallic elements.

[0243] CAC-OS can be formed, for example, by sputtering without heating the substrate. When forming CAC-OS by sputtering, one or more gases selected from inert gases (typically argon), oxygen gases, and nitrogen gases can be used as the deposition gas. Furthermore, the lower the oxygen gas flow rate in the total flow rate of the deposition gas during film formation, the better; for example, it is preferable that the oxygen gas flow rate in the total flow rate of the deposition gas during film formation is 0% or more and less than 30%, more preferably 0% or more and less than 10%.

[0244] For example, in CAC-OS of In-Ga-Zn oxide, based on the EDX surface analysis (mapping) image obtained by Energy Dispersive X-ray spectroscopy (EDX), a structure with an unevenly distributed and mixed structure of regions with In as the main component (first region) and regions with Ga as the main component (second region) can be identified.

[0245] Here, the first region has higher conductivity than the second region. That is, when carriers flow through the first region, it exhibits the conductivity of a metal oxide. Therefore, when the first region is distributed in a cloud-like manner within the metal oxide, a high field mobility (μ) can be achieved.

[0246] On the other hand, the second region is a region with higher insulation than the first region. That is, when the second region is distributed in a metal oxide, leakage current can be suppressed.

[0247] When CAC-OS is used in transistors, the complementary effect of conductivity arising from the first region and insulation arising from the second region enables CAC-OS to possess switching functionality (the function of controlling conduction / turn-off). In other words, a part of the CAC-OS material has conductive functionality and another part has insulating functionality, while the entire material functions as a semiconductor. By separating the conductive and insulating functions, each function can be maximized. Therefore, by using CAC-OS in transistors, high on-state current (Ion), high field-effect mobility (μ), and good switching operation can be achieved.

[0248] Furthermore, transistors using CAC-OS exhibit high reliability. Therefore, CAC-OS is best suited for various semiconductor devices, including display devices.

[0249] Oxide semiconductors possess various structures and properties. In one embodiment of the present invention, the oxide semiconductor may also include two or more of the following: amorphous oxide semiconductor, polycrystalline oxide semiconductor, a-like OS, CAC-OS, nc-OS, and CAAC-OS.

[0250] This implementation method can be appropriately combined with other implementation methods.

[0251] Implementation Method 4 In this embodiment, a display device according to an embodiment of the present invention will be described with reference to FIG13.

[0252] The display device of this embodiment includes a plurality of pixels arranged in a matrix of m rows and n columns (where m and n are both integers greater than or equal to 1). Figure 13 shows an example of a circuit diagram of a pixel PIX(i,j) (where i is an integer greater than or equal to 1 and less than or equal to m, and j is an integer greater than or equal to 1 and less than or equal to n).

[0253] The pixel PIX(i,j) shown in Figure 13 includes the light-emitting diode 110, switch SW21, transistor M, and capacitor C1 described in Embodiment 1. Transistor M corresponds to transistor 120 or transistor 130d described in Embodiment 1. The pixel PIX(i,j) may also include switch SW22. The light-emitting diode 110 is preferably a miniature light-emitting diode or a small light-emitting diode.

[0254] This embodiment shows an example of using a transistor as a switch SW21. The gate of switch SW21 is electrically connected to scan line GL1(i). One of the source and drain of switch SW21 is electrically connected to signal line SL(j), and the other is electrically connected to the gate of transistor M.

[0255] This embodiment shows an example of using a transistor as a switch SW22. The gate of switch SW22 is electrically connected to scan line GL2(i). One of the source and drain of switch SW22 is electrically connected to wiring COM, and the other is electrically connected to the gate of transistor M.

[0256] The gate of transistor M is electrically connected to one electrode of capacitor C1, the other of the source and drain of switch SW21, and the other of the source and drain of switch SW22. One of the source and drain of transistor M is electrically connected to wiring CATHODE, and the other is electrically connected to the cathode of light-emitting diode 110.

[0257] The other electrode of capacitor C1 is electrically connected to the CATHODE wiring.

[0258] The anode of the light-emitting diode 110 is electrically connected to the wiring ANODE.

[0259] Scan line GL1(i) supplies selection signals. Scan line GL2(i) supplies control signals. Signal line SL(j) supplies image signals. Each of the wiring COM, wiring CATHODE, and wiring ANODE is supplied with a fixed potential. The potential on the anode side of the light-emitting diode 110 can be set to a high potential, while the potential on the cathode side can be set to a lower potential than that on the anode side.

[0260] Switch SW21 is controlled by a selection signal and is used as a selection transistor to control the selection state of pixel PIX(i,j).

[0261] Transistor M is used as a driving transistor to control the current flowing through the light-emitting diode 110 according to the potential supplied to the gate. When switch SW21 is in the on state, the image signal supplied to signal line SL(j) is supplied to the gate of transistor M, and the brightness of light emission of light-emitting diode 110 can be controlled according to its potential.

[0262] Switch SW22 has the function of controlling the gate potential of transistor M according to the control signal. Specifically, switch SW22 can supply the potential that makes transistor M non-conducting to the gate of transistor M.

[0263] For example, switch SW22 can be used for pulse width control. During the period based on the control signal, current can be supplied from transistor M to light-emitting diode 110. Alternatively, light-emitting diode 110 can represent grayscale based on image signal and control signal.

[0264] Here, as the transistors included in each pixel PIX(i,j), it is preferable to use metal oxide (oxide semiconductor) transistors for the semiconductor layer that forms the channel for each of them.

[0265] Using metal oxide transistors with a wider band gap and lower carrier concentration than silicon, extremely small off-state currents can be achieved. Therefore, because of their small off-state currents, the charge stored in the capacitor connected in series with the transistor can be maintained for a long period. Therefore, in particular, it is preferable to use oxide semiconductor transistors as switches SW21 and SW22 connected in series with capacitor C1. Furthermore, by using oxide semiconductor transistors in other transistors, manufacturing costs can be reduced.

[0266] Furthermore, the transistors included in the pixel PIX(i,j) can be silicon transistors, which are semiconductors used to form the channels. In particular, it is preferable to use silicon with high crystallinity, such as monocrystalline silicon or polycrystalline silicon, which can achieve high field-efficiency mobility and higher operating speed.

[0267] Alternatively, the following structure can be adopted: one or more of the transistors included in the pixel PIX(i,j) are oxide semiconductor transistors, and silicon transistors are used as other transistors.

[0268] Note that in Figure 13, the transistor is represented as an n-channel transistor, but a p-channel transistor can also be used.

[0269] This implementation method can be appropriately combined with other implementation methods.

[0270] Implementation Method 5 In this embodiment, an electronic device according to one embodiment of the present invention will be described using Figures 14A to 19F.

[0271] The electronic device of this embodiment includes a display device according to one embodiment of the present invention in its display section. The display device according to one embodiment of the present invention has high display quality and low power consumption. Furthermore, the display device according to one embodiment of the present invention is easily made to achieve high definition and high resolution. Therefore, it can be used in the display section of various electronic devices.

[0272] As electronic devices, in addition to electronic devices with large screens such as televisions, desktop or laptop personal computers, monitors for computers, digital signage, and large game consoles such as pinball machines, other examples include digital cameras, digital camcorders, digital photo frames, mobile phones, portable game consoles, portable information terminals, and audio playback devices.

[0273] In particular, because the display device of one embodiment of the present invention can improve clarity, it can be suitably used in electronic devices that include a small display section. Examples of such electronic devices include watch-type or bracelet-type information terminal devices (wearable devices), VR devices such as head-mounted displays, glasses-type AR devices, MR devices, XR devices, or wearable devices that can be worn on the head.

[0274] A display device according to one embodiment of the present invention preferably has extremely high resolution, such as HD (1280×720 pixels), FHD (1920×1080 pixels), WQHD (2560×1440 pixels), WQXGA (2560×1600 pixels), 4K (3840×2160 pixels), 8K (7680×4320 pixels), etc. In particular, it is preferred to set the resolution to 4K, 8K, or higher. Furthermore, the pixel density (clarity) in the display device according to one embodiment of the present invention is preferably 300 ppi or higher, more preferably 500 ppi or higher, further preferably 1000 ppi or higher, even more preferably 3000 ppi or higher, still more preferably 5000 ppi or higher, and even more preferably 7000 ppi or higher. By using the aforementioned high-resolution display devices, the sense of realism and depth can be further enhanced in personal electronic devices such as portable or home-use devices.

[0275] The electronic device in this embodiment may also include a sensor (which has the function of measuring factors such as force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, tilt, vibration, odor, or infrared radiation).

[0276] The electronic device of this embodiment can have various functions. For example, it can have the following functions: displaying various information (still images, moving images, text images, etc.) on the display unit; touch panel function; displaying calendar, date or time, etc.; executing various software (programs); performing wireless communication function; reading programs or data stored in the storage medium; etc.

[0277] Figure 14A shows a perspective view of an eyeglass-type electronic device 700. The electronic device 700 includes a pair of display panels 701, a pair of housings 702, a pair of optical components 703, a pair of mounting parts 704, a frame 707, a nose pad 708, etc.

[0278] The electronic device 700 can project an image displayed by the display panel 701 onto a display area 706 in an optical component 703. Because the optical component 703 is transparent, the user can see the image displayed in the display area 706 by superimposing it with the image seen through the optical component 703. Therefore, the electronic device 700 is an electronic device capable of AR display.

[0279] One or both of the housing 702 may be equipped with a camera capable of capturing images from the front. Additionally, the housing 702 may have a wireless communication device, through which image signals can be supplied to the housing 702. Furthermore, instead of or in addition to the wireless communication device, a connector capable of connecting wires for supplying image signals or power can be included. Furthermore, by providing an accelerometer such as a gyroscope sensor in the housing 702, the orientation of the user's head can be detected, and an image corresponding to that orientation can be displayed on the display area 706.

[0280] One or both of the housings 702 may also be equipped with a processor. The processor has functions such as controlling various components included in the electronic device 700, including the camera, wireless communication device, and a pair of display panels 701, as well as generating images. The processor may also have the function of generating synthetic images for AR display.

[0281] Furthermore, wireless communication devices can communicate with external devices. For example, data transmitted from the outside can be output to a processor, which can then generate image data for AR display based on that data. In addition to image data, other types of data transmitted from the outside include biometric information transmitted from devices such as biosensors.

[0282] The image projection method relative to the display area 706 of the electronic device 700 will be described with reference to FIG14B. A display panel 701 is provided inside the housing 702. In addition, a reflector 712 is provided in the optical component 703, and a reflective surface 713 serving as a semi-reflective mirror is provided in the portion corresponding to the display area 706 in the optical component 703.

[0283] The light 715 emitted by the display panel 701 is reflected by the reflector 712 onto one side of the optical component 703. Inside the optical component 703, the light 715 undergoes repeated total internal reflection at the end face of the optical component 703, and when it reaches the reflective surface 713, the image is projected onto the reflective surface 713. Thus, the user can see the light 715 reflected on the reflective surface 713 and the transmitted light 716 passing through the optical component 703 (including the reflective surface 713).

[0284] Figure 14B shows an example where both the reflector 712 and the reflecting surface 713 are curved. This increases the flexibility of the optical design compared to cases where they are planar, allowing for a reduction in the thickness of the optical component 703. Alternatively, the reflector 712 and the reflecting surface 713 can also be planar.

[0285] As the reflector 712, a component with a mirror surface can be used, and the reflector preferably has a high reflectivity. In addition, as the reflective surface 713, a semi-reflective mirror that utilizes the reflection of a metal film can also be used, but when a prism or the like that that utilizes total internal reflection is used, the transmittance of the transmitted light 716 can be increased.

[0286] Here, the housing 702 may also include a lens between the display panel 701 and the reflector 712. In this case, the housing 702 preferably has a mechanism for adjusting the distance and angle between the lens and the display panel 701. This allows for focus adjustment and image magnification / reduction. For example, one or both of the lens and the display panel 701 can be movable along the optical axis.

[0287] Furthermore, the housing 702 preferably has a mechanism capable of adjusting the angle of the reflector 712. By changing the angle of the reflector 712, the position of the display area 706 for displaying the image can be changed. Thus, the display area 706 can be positioned in the most suitable location according to the user's eye position.

[0288] The housing 702 preferably houses a battery 717 and a wireless power supply module 718. By including the battery 717, the electronic device 700 can be used without a separate battery connection, thus improving convenience. Furthermore, by including the wireless power supply module 718, wireless charging is possible, further enhancing convenience and design. Moreover, compared to wired charging using connectors, the risk of malfunctions such as poor connections is reduced, thereby improving the reliability of the electronic device 700.

[0289] The housing 702 is equipped with a touch sensor module 719. The touch sensor module 719 has the function of detecting whether the outer surface of the housing 702 is touched. Figure 14B shows the case where a finger 720 touches the surface of the housing 702. With the touch sensor module 719, various processes can be performed by detecting user tap or swipe operations. For example, the tap operation can be used to perform processing such as temporarily pausing or replaying moving images, or the swipe operation can be used to perform processing such as fast forward and rewind. In addition, by providing a touch sensor module 719 in each of the two housings 702, the operating range can be expanded.

[0290] Various touch sensors can be used as the touch sensor module 719. For example, capacitive, resistive, infrared, electromagnetic, surface acoustic wave, and optical sensors can be employed. In particular, it is preferred to use capacitive or optical sensors in the touch sensor module 719.

[0291] When using optical touch sensors, photoelectric conversion devices (also called photoelectric conversion elements) can be used as light-receiving devices (also called light-receiving elements). Examples of photoelectric conversion devices include those using inorganic semiconductors as the active layer or those using organic semiconductors.

[0292] The display panel 701 can be applied to a display device according to one embodiment of the present invention. Therefore, an electronic device 700 capable of displaying with extremely high clarity can be realized.

[0293] Figure 15A shows a perspective view of an eyeglass-type electronic device 900. The electronic device 900 includes a pair of display panels 901, a pair of housings 902, a pair of optical components 903, a pair of mounting parts 904, etc.

[0294] The electronic device 900 can project an image displayed on the display panel 901 onto a display area 906 in an optical component 903. Because the optical component 903 is transparent, the user can see the image displayed on the display area 906 by superimposing it with the image seen through the optical component 903. Therefore, the electronic device 900 is an electronic device capable of AR display.

[0295] In addition to its image display function, the display panel 901 included in the electronic device 900 preferably also has a camera function. In this case, the electronic device 900 can receive light incident on the display panel 901 through the optical component 903 and convert it into an electrical signal for output. Thus, it can capture images of the user's eyes or the area around the eyes and output them externally or to the computing unit included in the electronic device 900 as image information.

[0296] One housing 902 is equipped with a front-facing camera 905. Furthermore, although not shown, each housing 902 is equipped with a wireless receiver or a connector for cable connection, allowing image signals to be supplied to the housing 902. Additionally, by incorporating an accelerometer such as a gyroscope into the housing 902, the orientation of the user's head can be detected, and an image corresponding to that orientation can be displayed on the display area 906. Preferably, the housing 902 houses a battery, which is preferably capable of being charged wirelessly or via a wired connection.

[0297] The image projection method relative to the display area 906 of the electronic device 900 will be described with reference to FIG15B. A display panel 901, a lens 911, and a reflector 912 are disposed inside the housing 902. Furthermore, the portion of the display area 906 corresponding to the optical component 903 includes a reflective surface 913 that serves as a semi-reflective mirror.

[0298] The light 915 emitted by the display panel 901 is reflected by the reflector 912 through the lens 911 onto one side of the optical component 903. Inside the optical component 903, the light 915 undergoes repeated total internal reflection at the end face of the optical component 903, and when it reaches the reflective surface 913, the image is projected onto the reflective surface 913. Thus, the user can see both the light 915 reflected on the reflective surface 913 and the transmitted light 916 that has passed through the optical component 903 (including the reflective surface 913).

[0299] Figure 15B shows an example where both the reflector 912 and the reflecting surface 913 are curved. This increases the flexibility of the optical design compared to cases where they are planar, allowing for a reduction in the thickness of the optical component 903. Alternatively, the reflector 912 and the reflecting surface 913 can also be planar.

[0300] As the reflector 912, a component with a mirror surface can be used, and the reflector preferably has a high reflectivity. In addition, as the reflective surface 913, a semi-reflective mirror that utilizes the reflection of a metal film can also be used, but when a prism or the like that that utilizes total internal reflection is used, the transmittance of the transmitted light 916 can be increased.

[0301] Here, the electronic device 900 preferably has a mechanism that adjusts one or both of the distance and angle between the lens 911 and the display panel 901. This allows for focus adjustment and image magnification / reduction. For example, a structure in which one or both of the lens 911 and the display panel 901 can move along the optical axis is sufficient.

[0302] The electronic device 900 preferably has a mechanism capable of adjusting the angle of the reflector 912. By changing the angle of the reflector 912, the position of the display area 906 for displaying the image can be changed. Thus, the display area 906 can be positioned in the most suitable location according to the user's eye position.

[0303] The display panel 901 can be applied to a display device according to one embodiment of the present invention. Therefore, an electronic device 900 capable of displaying with extremely high clarity can be realized.

[0304] Figures 16A and 16B show perspective views of the goggle-type electronic device 950. Figure 16A is a perspective view showing the front, plan, and left side of the electronic device 950, and Figure 16B is a perspective view showing the back, bottom, and right side of the electronic device 950.

[0305] The electronic device 950 includes a pair of display panels 951, a housing 952, a pair of mounting parts 954, a buffer member 955, a pair of lenses 956, etc. Each of the pair of display panels 951 is located inside the housing 952 in a position that can be seen through the lens 956.

[0306] Electronic device 950 is a VR electronic device. Users who have installed electronic device 950 can see the image displayed on display panel 951 through lens 956. In addition, by displaying different images on a pair of display panels 951, three-dimensional display utilizing parallax can also be performed.

[0307] An input terminal 957 and an output terminal 958 are provided on one side of the back of the housing 952. Cables supplying image signals from image output devices or power for charging a battery housed within the housing 952 can be connected to the input terminal 957. The output terminal 958 is used, for example, as an audio output terminal and can be connected to headphones or headsets. Alternatively, if audio data can be output via wireless communication or if audio is output from an external image output device, this audio output terminal may not be required.

[0308] The electronic device 950 preferably has a mechanism that allows adjustment of the left and right positions of the lens 956 and the display panel 951 to position them in the most suitable way according to the user's eye position. Furthermore, it is also preferred to have a mechanism that adjusts the focus by changing the distance between the lens 956 and the display panel 951.

[0309] The display panel 951 can be used with a display device according to one embodiment of the present invention. Therefore, an electronic device 950 capable of displaying extremely high definition can be realized. As a result, the user can experience a high degree of immersion.

[0310] The cushioning member 955 is the part that contacts the user's face (forehead, cheek, etc.). By ensuring a close contact between the cushioning member 955 and the user's face, light leakage can be prevented, thereby further enhancing immersion. The cushioning member 955 is preferably made of a soft material to ensure a close contact with the user's face when the electronic device 950 is installed. For example, materials such as rubber, silicone rubber, polyurethane, and sponge can be used. Furthermore, when the cushioning member 955 is made of a component that covers the surface of the sponge or similar material with cloth or leather (natural or synthetic leather), gaps are less likely to form between the user's face and the cushioning member 955, thus appropriately preventing light leakage. It is preferable that components in contact with the user's skin, such as the cushioning member 955 and the mounting part 954, have a detachable structure for easy cleaning and replacement.

[0311] The electronic device 6500 shown in Figure 17A is a portable information terminal device that can be used as a smartphone.

[0312] The electronic device 6500 includes a housing 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508. The display unit 6502 has a touch panel function.

[0313] The display unit 6502 may use a display device according to one embodiment of the present invention.

[0314] Figure 17B is a cross-sectional view of one end of the microphone 6506, including the housing 6501.

[0315] A light-transmitting protective member 6510 is provided on one side of the display surface of the housing 6501. The space surrounded by the housing 6501 and the protective member 6510 contains a display panel 6511, an optical member 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc.

[0316] The display panel 6511, optical component 6512 and touch sensor panel 6513 are fixed to the protective component 6510 using an adhesive layer (not shown).

[0317] In the area outside the display unit 6502, a portion of the display panel 6511 is folded back, and this folded portion is connected to an FPC 6515. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to terminals disposed on a printed circuit board 6517.

[0318] The display panel 6511 can be a flexible display. This allows for the realization of extremely lightweight electronic devices. Furthermore, because the display panel 6511 is extremely thin, a large-capacity battery 6518 can be installed while minimizing the thickness of the electronic device. Additionally, by folding a portion of the display panel 6511 to provide a connection to the FPC 6515 on the back of the pixel section, a narrow-bezel electronic device can be achieved.

[0319] Figure 18A shows an example of a television set. In the television set 7100, a display unit 7000 is assembled in a housing 7101. The structure in which the housing 7101 is supported by a bracket 7103 is shown here.

[0320] The display unit 7000 may use a display device according to one embodiment of the present invention.

[0321] The television 7100 shown in FIG18A can be operated using the operation switch provided in the housing 7101 or the separately provided remote control 7111. Alternatively, a touch sensor can be provided in the display unit 7000, allowing operation of the television 7100 by touching the display unit 7000 with a finger or similar object. Furthermore, the remote control 7111 can also have a display unit that displays data output from the remote control 7111. Using the operation keys or touch panel provided in the remote control 7111, channel and volume can be adjusted, and the images displayed on the display unit 7000 can be manipulated.

[0322] In addition, the 7100 television set includes a receiver and a modem. The receiver can be used to receive general television broadcasts. Furthermore, the modem connects to wired or wireless communication networks, enabling one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0323] Figure 18B shows an example of a notebook computer. The notebook computer 7200 includes a casing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, etc. A display unit 7000 is assembled in the casing 7211.

[0324] The display unit 7000 may use a display device according to one embodiment of the present invention.

[0325] Figures 18C and 18D show an example of a digital signage.

[0326] The digital signage 7300 shown in Figure 18C includes a housing 7301, a display unit 7000, and a speaker 7303. It may also include LEDs, operation keys (including a power switch or operation switch), connection terminals, various sensors, a microphone, etc.

[0327] Figure 18D shows a digital signage 7400 mounted on a cylindrical column 7401. The digital signage 7400 includes a display section 7000 disposed along the curved surface of the column 7401.

[0328] In Figures 18C and 18D, a display device according to one embodiment of the present invention can be used in the display unit 7000.

[0329] The larger the display unit (7000), the more information it can provide at once. A larger display unit (7000) is also more likely to attract attention, which can improve the effectiveness of advertising.

[0330] By using a touch panel for the display unit 7000, not only can static or dynamic images be displayed on the display unit 7000, but users can also operate it intuitively, which is superior. In addition, when used to provide information such as route information or traffic information, intuitive operation can improve ease of use.

[0331] As shown in Figures 18C and 18D, the digital signage 7300 or 7400 is preferably able to wirelessly communicate with a user's smartphone or other information terminal device 7311 or 7411. For example, advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal device 7311 or 7411. Furthermore, the display on the display unit 7000 can be switched by operating the information terminal device 7311 or 7411.

[0332] Furthermore, the game can be executed on the digital signage 7300 or 7400 using the screen of information terminal device 7311 or 7411 as the operating unit (controller). Thus, multiple users can participate in the game simultaneously and enjoy the experience.

[0333] The electronic devices shown in Figures 19A to 19F include a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), a connection terminal 9006, a sensor 9007 (which has the function of measuring the following factors: force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, tilt, vibration, odor, or infrared radiation), a microphone 9008, etc.

[0334] The electronic devices shown in Figures 19A to 19F have various functions. For example, they may have the following functions: displaying various information (still images, moving images, and text images, etc.) on a display unit; a touch panel function; displaying a calendar, date, or time; controlling processing using various software (programs); performing wireless communication; reading and processing programs or data stored in a storage medium; etc. Note that the functions of an electronic device are not limited to the above-mentioned functions, but can have various functions. An electronic device may include multiple display units. Additionally, a camera or similar device may be installed in the electronic device to enable it to have the following functions: capturing still or moving images and storing the captured images in a storage medium (external storage medium or storage medium built into the camera); displaying the captured images on a display unit; etc.

[0335] The electronic devices shown in Figures 19A to 19F will now be described in detail.

[0336] Figure 19A is a perspective view showing a portable information terminal 9101. The portable information terminal 9101 can be used, for example, as a smartphone. Note that a speaker 9003, a connection terminal 9006, a sensor 9007, etc., can also be provided in the portable information terminal 9101. Furthermore, as a portable information terminal 9101, text or image information can be displayed on multiple surfaces. Examples of three illustrations 9050 are shown in Figure 19A. Additionally, information 9051, shown as a dashed rectangle, can be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of received emails, SNS messages, or phone calls; the subject of emails or SNS messages; the sender's name; the date; the time; remaining battery level; and the display of radio wave intensity. Alternatively, illustrations 9050 can be displayed in the same locations where information 9051 is displayed.

[0337] Figure 19B is a perspective view showing a portable information terminal 9102. The portable information terminal 9102 has the function of displaying information on three or more surfaces of the display unit 9001. Here, examples are shown where information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, when the portable information terminal 9102 is placed in a jacket pocket, the user can check information 9053 displayed in a position visible from above the portable information terminal 9102. For example, the user can check this display without taking the portable information terminal 9102 out of their pocket, thereby determining whether to answer a phone call.

[0338] Figure 19C is a perspective view showing a watch-type portable information terminal 9200. The portable information terminal 9200 can be used, for example, as a smartwatch. Furthermore, the display surface of the display unit 9001 is curved, allowing display along the curved surface. In addition, the portable information terminal 9200 can perform hands-free calls, for example, by communicating with a headset capable of wireless communication. Furthermore, by using the connection terminal 9006, the portable information terminal 9200 can transmit data and charge with other information terminals. Charging can also be performed wirelessly.

[0339] Figures 19D to 19F are perspective views showing the foldable portable information terminal 9201. Figure 19D is a perspective view of the portable information terminal 9201 in its unfolded state, Figure 19F is a perspective view of its folded state, and Figure 19E is a perspective view of the state intermediate when transitioning from one of the states in Figures 19D and 19F to the other. The portable information terminal 9201 offers good portability in its folded state, and its unfolded state provides excellent browsing due to its large, seamlessly integrated display area. The display unit 9001 included in the portable information terminal 9201 is supported by three housings 9000 connected by hinges 9055. The display unit 9001 can be bent, for example, within a radius of curvature of 0.1 mm or more and 150 mm or less.

[0340] This implementation method can be appropriately combined with other implementation methods.

[0341] 11: Floor 12: Floor 13: Floor 14: Floor 15: Floor 16: Floor 17: Floor 20B: pixels 20G: pixels 20R: pixels 100A: Display device 100B: Display device 100C: Display device 100D: Display device 100E: Display device 100F: Display device 102: Insulation layer 103: Insulation layer 104: Insulation layer 110: Light Emitting Diode 110B: Light Emitting Diode 110G: Light Emitting Diode 110R: Light Emitting Diode 113: Semiconductor layer 113a: Semiconductor layer 114: Emissive Layer 114a: Emissive layer 114b: Emissive layer 115: Semiconductor layer 115a: Semiconductor layer 115b: Semiconductor layer 120: Transistor 120C: Transistor 120e: Transistor 130: Transistor 130d: Transistor 130e: Transistor 130F: Transistor 130g: Transistor 132: Component Separation Layer 133: Low resistance region 134: Insulation layer 135: Conductive layer 136: Insulation layer 137: Conductive layer 138: Conductive layer 139: Insulation layer 141: Insulation layer 142: Insulation layer 143: Insulation layer 151:Substrate 152:Substrate 153: Silicon substrate 154:Substrate 161: Conductive layer 162: Insulation layer 163: Insulation layer 164: Insulation layer 165: Metal oxide layer 166: Conductive layer 167: Insulation layer 168: Conductive layer 171:Substrate 173: Insulation layer 174: Conductive layer 175: Conductive layer 176: Conductor 177: Conductive layer 178: Conductive layer 179: Adhesive layer 181: Insulation layer 182: Insulation layer 183: Insulation layer 184a: Conductive layer 184b: Conductive layer 185: Insulation layer 186: Insulation layer 187: Insulation layer 188: Insulation layer 189: Conductive layer 190a: Conductive layer 190b: Conductive layer 190c: Conductive layer 191a: Conductive layer 191b: Conductive layer 191c: Conductive layer 192: Conductive layer 193: Reflective layer 194: Conductive layer 195: Conductive layer 196: Conductive layer 197: Conductor 200: Transistor 205: Conductor 205a: Conductor 205b: Conductor 212: Insulator 214: Insulator 216: Insulator 222: Insulator 224: Insulator 230: Oxides 230a: Oxide 230b: Oxide 240: Conductor 240a: Conductor 240b: Conductor 241: Insulator 241a: Insulator 241b: Insulator 242: Conductor 242a: Conductor 242b: Conductor 243: Oxides 243a: Oxide 243b: Oxide 246: Conductor 246a: Conductor 246b: Conductor 250: Insulator 250a: Insulator 250b: Insulator 260: Conductor 260a: Conductor 260b: Conductor 271: Insulator 271a: Insulator 271b: Insulator 275: Insulator 280: Insulator 282: Insulator 283: Insulator 285: Insulator 300:Substrate 310: Peel-off layer 320: Adhesive layer 330:Substrate 350: Light-shielding layer 351: Light-shielding layer 360B: Color Conversion Layer 360G: Color Conversion Layer 360R: Color Conversion Layer 361B: Color Layer 361G: Color Layer 361R: Color Layer 401: Pixel section 402: Area 500: Adhesive layer 501:FPC 502:FPC 700: Electronic Devices 701: Display Panel 702: Outer shell 703: Optical Components 704: Installation Department 706: Display Area 707: Border 708: Nose pad 712: Reflector 713: Reflective surface 715: Light 716: Through the light 717: Battery 718: Wireless Power Supply Module 719: Touch Sensor Module 720: fingers 900: Electronic Devices 901: Display Panel 902: Outer shell 903: Optical Components 904: Installation Department 905: Camera 906: Display area 911: Lens 912: Reflector 913: Reflective surface 915: Light 916: Through the light 950: Electronic devices 951: Display panel 952: Outer shell 954: Installation Department 955: Buffer component 956: Lens 957: Input Terminal 958: Output Terminal 6500: Electronic Devices 6501: Casing 6502: Display Unit 6503: Power button 6504: Button 6505: Speaker 6506: Microphone 6507: Camera 6508: Light Source 6510: Protective components 6511: Display panel 6512: Optical components 6513: Touch sensor panel 6515:FPC 6516:IC 6517: Printed Circuit Board 6518: Battery 7000: Display Section 7100: Television 7101: Outer casing 7103: Bracket 7111: Remote Control 7200: Notebook PC 7211: Outer casing 7212: Keyboard 7213: Pointing device 7214: External connection port 7300: Digital Kanban 7301: Outer casing 7303: Speaker 7311: Information Terminal Equipment 7400: Digital Kanban 7401: Pillar 7411: Information Terminal Equipment 9000: Casing 9001: Display Unit 9003: Speaker 9005: Operation Key 9006: Connecting terminal 9007: Sensor 9008: Microphone 9050: Illustration 9051: News 9052: News 9053: News 9054: News 9055: Hinges 9101: Portable Information Terminal 9102: Portable Information Terminal 9200: Portable Information Terminal 9201: Portable Information Terminal

Claims

1. A display device, comprising: First layer; Second layer; The third layer; The system comprises a first layer and a fourth layer, wherein the second and third layers are disposed between the first and fourth layers. The second layer is disposed between the first and third layers. The first layer includes a first transistor, the second layer includes a second transistor, the third layer includes a reflective layer, a first conductive layer, and a second conductive layer, and the fourth layer includes a light-emitting diode (LED). The LED includes a first electrode and a second electrode. The first electrode is electrically connected to the first conductive layer, and the second electrode is electrically connected to the second conductive layer. The first and second transistors are transistors constituting a pixel circuit. Each of the first transistor, the second transistor, the reflective layer, and the LED has overlapping areas. A first insulating layer is disposed between the first transistor and the second transistor. A second insulating layer is disposed between the second transistor and the reflective layer. The reflective layer has an area in contact with the second insulating layer. The first conductive layer has an area in contact with the second insulating layer. The second conductive layer has an area in contact with the second insulating layer. A third insulating layer is disposed between the reflective layer and the LED. The light-emitting diode includes a semiconductor layer, and the semiconductor layer has a region in contact with the third insulating layer.

2. A display device, comprising: First layer; Second layer; The third layer; The system comprises a second layer and a third layer, wherein the second layer is disposed between the first layer and the fourth layer, the second layer is disposed between the first layer and the third layer, the first layer includes a first transistor, the second layer includes a second transistor, the third layer includes a reflective layer, a first conductive layer and a second conductive layer, the reflective layer has the same material as the first conductive layer and the second conductive layer, the fourth layer includes a light-emitting diode, the light-emitting diode includes a first electrode and a second electrode, the first electrode is electrically connected to the first conductive layer, the second electrode is electrically connected to the second conductive layer, the first transistor and the second transistor are transistors constituting a pixel circuit, the first transistor, the second transistor, the reflective layer and the light-emitting diode each have overlapping areas, a first insulating layer is disposed between the first transistor and the second transistor, a second insulating layer is disposed between the second transistor and the reflective layer, a third insulating layer is disposed between the reflective layer and the light-emitting diode, the light-emitting diode includes a semiconductor layer, and the semiconductor layer has an area in contact with the third insulating layer.

3. The display device as described in claim 1 or 2 further includes: The fifth layer is provided such that the fourth layer is sandwiched between the third layer and the fifth layer. The fifth layer includes one or both of a color conversion layer and a color layer. The color conversion layer and the color layer, the first transistor, the second transistor, the reflective layer and the light-emitting diode each have overlapping areas. A fourth insulating layer is provided between the light-emitting diode and one or both of the color conversion layer and the color layer.

4. The display device as claimed in claim 3, wherein the color conversion layer comprises a phosphor or a quantum dot.

5. The display device of claim 1 or 2, wherein the first transistor contains silicon in the channel forming region.

6. The display device of claim 1 or 2, wherein the second transistor includes a metal oxide in the channel forming region, and the metal oxide comprises In, Zn and M, wherein M is one or more of Al, Ti, Ga, Ge, Sn, Y, Zr, La, Ce, Nd and Hf.

7. The display device of claim 1 or 2, wherein the semiconductor layer is a compound semiconductor containing elements of group 13 and group 15.

8. The display device as requested in item 1 or 2, wherein the light-emitting diode emits blue light, blue-violet light, violet light or ultraviolet light.

9. An electronic device comprising: The display device requested in item 1 or 2; And one or more of the following: battery, casing, camera, speaker, and microphone.

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