Light-emitting device and substrate for forming light-emitting device

Abstract

To provide a light-emitting device including a gallium nitride film formed on a large substrate such as an amorphous glass substrate, in which the light extraction efficiency is improved.SOLUTION: A light-emitting device includes a plurality of pixels arranged in matrix in a first direction and a second direction intersecting with the first direction. Each of the pixels includes an amorphous substrate and a transflective layer on the amorphous substrate, a first insulating alignment layer on the transflective layer, a first semiconductor layer on the first insulating alignment layer, a light-emitting layer on the first semiconductor layer, a second semiconductor layer on the light-emitting layer, and an electrode layer on the second semiconductor layer. Each of the first semiconductor layer, the light-emitting layer, and the second semiconductor layer contains gallium nitride.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] One embodiment of the present invention relates to a light-emitting device containing gallium nitride. Another embodiment of the present invention relates to a light-emitting device forming substrate on which a plurality of light-emitting devices containing gallium nitride are formed. [Background technology]

[0002] Gallium nitride (GaN) is a direct transition semiconductor characterized by its large bandgap. Taking advantage of gallium nitride's properties, light-emitting diodes (LEDs) using gallium nitride films have already been put into practical use. Generally, gallium nitride films for LEDs are deposited on sapphire substrates at high temperatures of 800°C to 1000°C using MOCVD (Metal Organic Chemical Vapor Deposition) or HVPE (Hydride Vapor Phase Epitaxy).

[0003] Incidentally, in recent years, development has been progressing on so-called micro-LED displays or mini-LED displays, which are next-generation display devices (or next-generation light-emitting devices) that have tiny LED chips mounted within the pixels of a circuit board. Micro-LED displays or mini-LED displays have high efficiency, high brightness, and high reliability. Such micro-LED displays or mini-LED displays are manufactured by transferring LED chips onto a backplane on which thin-film transistors made of oxide semiconductors or low-temperature polysilicon are formed (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] U.S. Patent No. 8791474 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, the manufacturing method of micro-LED displays by transferring LED chips is costly, making it difficult to produce micro-LED displays cheaply. On the other hand, if LEDs can be formed on a large-area substrate such as an amorphous glass substrate, manufacturing costs can be reduced. However, as mentioned above, since gallium nitride films are deposited on sapphire substrates at high temperatures, it is difficult to directly form a gallium nitride film on an amorphous glass substrate.

[0006] Furthermore, even when a gallium nitride film is formed directly on an amorphous glass substrate, gallium nitride is a high refractive index material, so there was a need to improve the light extraction efficiency.

[0007] One embodiment of the present invention aims to provide a light-emitting device with improved light extraction efficiency, which includes a gallium nitride film formed on a large-area substrate such as an amorphous glass substrate, in view of the above-mentioned problems. Another embodiment of the present invention aims to provide a light-emitting device forming substrate on which a plurality of light-emitting devices with improved light extraction efficiency are formed, which include a gallium nitride film. [Means for solving the problem]

[0008] A light-emitting device according to one embodiment of the present invention includes a plurality of pixels arranged in a matrix in a first direction and a second direction intersecting the first direction, each of the plurality of pixels includes an amorphous substrate, a semi-transparent reflective layer on the amorphous substrate, a first insulating orientation layer on the semi-transparent reflective layer, a first semiconductor layer on the first insulating orientation layer, a light-emitting layer on the first semiconductor layer, a second semiconductor layer on the light-emitting layer, and an electrode layer on the second semiconductor layer, each of the first semiconductor layer, the light-emitting layer, and the second semiconductor layer includes gallium nitride.

[0009] A light-emitting device according to one embodiment of the present invention includes a plurality of pixels arranged in a matrix in a first direction and a second direction intersecting the first direction, each of the plurality of pixels includes an amorphous substrate, a first insulating orientation layer on the amorphous substrate, a semi-transparent reflective layer on the first insulating orientation layer, a first semiconductor layer on the semi-transparent reflective layer, a light-emitting layer on the first semiconductor layer, a second semiconductor layer on the light-emitting layer, and an electrode layer on the second semiconductor layer, each of the first semiconductor layer, the light-emitting layer, and the second semiconductor layer includes gallium nitride.

[0010] A light-emitting device according to one embodiment of the present invention includes a plurality of pixels arranged in a matrix in a first direction and a second direction intersecting the first direction, each of the plurality of pixels includes an amorphous substrate, a first insulating orientation layer on the amorphous substrate, an electrode layer on the first insulating orientation layer, a first semiconductor layer on the electrode layer, a light-emitting layer on the first semiconductor layer, a second semiconductor layer on the light-emitting layer, and a semi-transparent reflective layer on the second semiconductor layer, each of the first semiconductor layer, the light-emitting layer, and the second semiconductor layer includes gallium nitride.

[0011] A light-emitting device forming substrate according to one embodiment of the present invention includes a plurality of the above-mentioned light-emitting devices, and the amorphous substrate is a single substrate common to the plurality of light-emitting devices. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing the configuration of a light-emitting device according to one embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view showing the pixel configuration of a light-emitting device according to one embodiment of the present invention. [Figure 3] This is a schematic cross-sectional view showing the region in Figure 2. [Figure 4A] This is a schematic cross-sectional view showing the pixel configuration of a light-emitting device according to one embodiment of the present invention. [Figure 4B] This is a schematic cross-sectional view showing the pixel configuration of a light-emitting device according to one embodiment of the present invention. [Figure 5] This is a schematic cross-sectional view showing the region of Figure 4A or Figure 4B. [Figure 6] It is a schematic cross-sectional view showing the configuration of a pixel of a light-emitting device according to an embodiment of the present invention. [Figure 7] It is a schematic cross-sectional view showing the region of FIG. 6. [Figure 8] It is a schematic cross-sectional view showing the configuration of a pixel of a light-emitting device according to an embodiment of the present invention. [Figure 9] It is a schematic cross-sectional view showing the region of FIG. 8. [Figure 10] It is a graph showing the current efficiency with respect to the change in chromaticity (y coordinate of the chromaticity coordinates) in the microcavity structure of the region shown in FIG. 3. [Figure 11] It is a graph showing the current efficiency with respect to the change in chromaticity (y coordinate of the chromaticity coordinates) in the microcavity structure of the region shown in FIG. 5. [Figure 12] It is a graph showing the current efficiency with respect to the change in chromaticity (y coordinate of the chromaticity coordinates) in the microcavity structure of the region shown in FIG. 7. [Figure 13] It is a schematic cross-sectional view showing the region of a comparative example without a microcavity structure. [Figure 14] It is a graph showing the current efficiency with respect to the change in chromaticity (y coordinate of the chromaticity coordinates) in the structure of the region of the comparative example shown in FIG. 13. [Figure 15] It is a schematic diagram showing the configuration of a light-emitting device formation substrate according to an embodiment of the present invention.

MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, each embodiment according to the present invention will be described with reference to the drawings. Note that each embodiment is merely an example, and what can be easily conceived by those skilled in the art by appropriately changing while maintaining the gist of the invention is naturally included in the scope of the present invention. In addition, for the sake of clearer explanation, in the drawings, the width, thickness, shape, etc. of each part may be schematically represented compared to the actual aspect. However, the illustrated shape etc. are merely examples and do not limit the interpretation of the present invention.

[0014] In this specification, expressions such as "α includes A, B, or C," "α includes any one of A, B, and C," and "α includes one selected from the group consisting of A, B, and C" do not exclude cases where α includes multiple combinations of A, B, and C, unless otherwise explicitly stated. Furthermore, these expressions do not exclude cases where α includes other elements.

[0015] In this specification, for the sake of explanation, the terms "up" or "above" or "down" or "below" will be used. However, as a general rule, the substrate on which the structure is formed is used as the reference point, and the direction from the substrate toward the structure is defined as "up" or "above." Conversely, the direction from the structure toward the substrate is defined as "down" or "below." Therefore, in the expression "structure on a substrate," the surface of the structure facing the substrate is the bottom surface of the structure, and the opposite surface is the top surface of the structure. Furthermore, the expression "structure on a substrate" merely describes the hierarchical relationship between the substrate and the structure, and other components may be placed between the substrate and the structure. In addition, the terms "up" or "above" or "down" or "below" refer to the stacking order in a structure with multiple layers, and do not necessarily mean that the layers are in a superimposed positional relationship in a plan view.

[0016] In this specification, the letters such as "1st," "2nd," or "3rd" attached to each component are merely convenient indicators used to distinguish each component, and unless otherwise specified, they have no further meaning.

[0017] In this specification and drawings, the same reference numeral is used to refer to multiple identical or similar components collectively, and uppercase letters may be added to distinguish each of these components. Furthermore, a hyphen and lowercase letters may be used to distinguish a part of a single component.

[0018] The following embodiments can be combined with each other, provided that no technical inconsistencies arise.

[0019] <First Embodiment> Referring to Figures 1 to 3, the configuration of the light-emitting device 100 according to one embodiment of the present invention will be described.

[0020] Figure 1 is a schematic diagram showing the configuration of a light-emitting device 100 according to one embodiment of the present invention. The light-emitting device 100 has a pixel section 100P and a terminal section 100T formed on an amorphous substrate 110. The pixel section 100P is formed in the central part of the amorphous substrate 110, and the terminal section 100T is formed at the edge of the amorphous substrate 110. The pixel section 100P includes a plurality of pixels 100-px arranged in a first direction and a second direction perpendicular (intersecting) to the first direction. As will be described in detail later, each of the plurality of pixels 100-px has a light-emitting diode (LED) formed on the amorphous substrate 110. The terminal section 100T includes a plurality of terminals 100-t. A power supply line is connected to each of the plurality of terminals 100-t, and a voltage can be applied (current can be supplied) to the LED in the pixel 100-px. Although not shown in detail, a thin-film transistor can also be provided in the pixel 100-px, and the light emission of the LED can be controlled by the thin-film transistor.

[0021] Figure 2 is a schematic cross-sectional view showing the configuration of a pixel 100-px of a light-emitting device 100 according to one embodiment of the present invention. Figure 3 is a schematic cross-sectional view showing region 300 in Figure 2. As shown in Figure 2, the pixel 100-px includes an amorphous substrate 110, a semi-transparent reflective layer 120, an insulating alignment layer 130, a first semiconductor layer 140, a light-emitting layer 150, a second semiconductor layer 160, a first electrode layer 170, and a second electrode layer 180. That is, the pixel 100-px is provided with an LED including the first semiconductor layer 140, the light-emitting layer 150, the second semiconductor layer 160, the first electrode layer 170, and the second electrode layer 180. The LED included in the pixel 100-px has a so-called horizontal electrode structure in which the first electrode layer 170 and the second electrode layer 180 are provided on one side of the light-emitting layer 150. In a 100-px pixel, the light emitted from the light-emitting layer 150 is extracted by passing through the amorphous substrate 110.

[0022] The semi-transparent reflective layer 120 is provided on the amorphous substrate 110. The semi-transparent reflective layer 120 may be provided in common for multiple pixels 100-px.

[0023] The insulating alignment layer 130 is provided on the semi-transparent reflective layer 120. The insulating alignment layer 130 may be provided in common to multiple pixels 100-px.

[0024] The first semiconductor layer 140, the light-emitting layer 150, and the second semiconductor layer 160 are provided on the insulating alignment layer 130 in this order. The first semiconductor layer 140 may be provided in common to multiple pixels 100-px. Each of the light-emitting layer 150 and the second semiconductor layer 160 is provided in an island-like manner within each of the pixels 100-px. That is, the first semiconductor layer 140 includes regions that are not covered by each of the light-emitting layer 150 and the second semiconductor layer 160.

[0025] The first electrode layer 170 is provided on the first semiconductor layer 140. Specifically, the first electrode layer 170 is provided in a region not covered by the light-emitting layer 150 and the second semiconductor layer 160. The second electrode layer 180 is provided on the second semiconductor layer 160. The first electrode layer 170 and the second electrode layer 180 are provided in an island-like manner within the 100-px pixel. That is, the first electrode layer 170 and the second electrode layer 180 are electrically isolated.

[0026] Although not shown in the figures, an insulating layer may be provided on the first semiconductor layer 140, the light-emitting layer 150, and the second semiconductor layer 160 so as to cover the light-emitting layer 150 and the second semiconductor layer 160. In this case, an opening is provided in the insulating layer. The first electrode layer 170 is provided so as to cover the opening in the insulating layer where the first semiconductor layer 140 is exposed, and the second electrode layer 180 is provided so as to cover the opening in the insulating layer where the second semiconductor layer 160 is exposed. In this case, at least one of the first electrode layer 170 and the second electrode layer 180 may be provided in an island-like manner within the pixel 100-px. The other of the first electrode layer 170 and the second electrode layer 180 may be provided in an island-like manner within the pixel 100-px, and may extend in a first or second direction and be provided in common to a plurality of pixels 100-px arranged in the first or second direction. In this case as well, the first electrode layer 170 and the second electrode layer 180 are electrically isolated.

[0027] Next, I will explain the materials used for each component.

[0028] The amorphous substrate 110 is the base material (support substrate) for the light-emitting device 100. As will be described in detail later, in the light-emitting device 100, the first semiconductor layer 140, the light-emitting layer 150, and the second semiconductor layer 160 are each formed on the amorphous substrate 110 using sputtering deposition. Therefore, the amorphous substrate 110 only needs to have heat resistance to a relatively low temperature, such as 400°C. For example, an amorphous glass substrate can be used as the amorphous substrate 110. Alternatively, a resin substrate such as a polyimide substrate, acrylic substrate, siloxane substrate, or fluororesin substrate can be used instead of the amorphous substrate 110. Such amorphous glass substrates or resin substrates are substrates that can be made into large areas. Alternatively, a polycrystalline substrate can be used instead of the amorphous substrate 110. Polycrystalline substrates can be made into larger areas than sapphire substrates which are commonly used in the deposition of gallium nitride films, and can be used as a base material for the light-emitting device 100, similar to amorphous glass substrates or resin substrates. Furthermore, the amorphous substrate may be provided with thin-film transistors for controlling the LEDs.

[0029] To describe the amorphous substrate 110 in more detail, it is preferable that the amorphous substrate 110 has a low coefficient of thermal expansion, a high strain point, and high surface flatness. For example, the amorphous substrate 110 has a coefficient of thermal expansion of 50 × 10⁻⁶. -7 The temperature is preferably less than / °C, and the strain point is preferably 600°C or higher. The amorphous substrate 110 only needs to have a heat resistance of about 400°C, and does not require the heat resistance of 1000°C or higher like a sapphire substrate. If the amorphous substrate 110 is an amorphous glass substrate, then, for example, a glass substrate formed from aluminoborosilicate glass or aluminosilicate glass can be used as an amorphous substrate 110 that satisfies the above characteristics. Such glass substrates are used in liquid crystal displays and organic electroluminescent (OLED) displays, and large-area glass substrates called mother glass are available on the market. Furthermore, it is preferable that the amorphous substrate 110 contains 0.1% or less of alkali metals such as sodium (Na).

[0030] Although not shown in the diagram, a base layer may be provided on the amorphous substrate 110. The base layer can prevent the diffusion of impurities from the amorphous substrate 110 or from the outside (e.g., water or sodium (Na)). As the base layer, for example, silicon nitride (SiN) x A film or the like can be used as the underlayer. Also, for example, silicon oxide (SiO2) can be used. x ) film and silicon nitride (SiN x ) A laminated film with a film can also be used.

[0031] The semi-transparent reflective layer 120 can transmit or reflect light emitted from the light-emitting layer 150 or light reflected by the second electrode layer 180. That is, each pixel 100-px includes a region 300 having a microcavity structure in which reflection is repeated between the semi-transparent reflective layer 120 and the second electrode layer 180. This improves the light extraction efficiency of the light-emitting device 100. Furthermore, the light-emitting device 100 exhibits minimal changes in light extraction efficiency due to chromaticity changes. As the semi-transparent reflective layer 120, for example, a metal such as silver (Ag) or magnesium (Mg), or an alloy thereof, can be used. These metals or alloys have a film thickness that allows light emitted from the light-emitting layer 150 or light reflected by the second electrode layer 180 to transmit. For example, the film thickness of the semi-transparent reflective layer 120 is 1 nm to 50 nm, preferably 5 nm to 30 nm.

[0032] The insulating orientation layer 130 can improve the crystallinity of the first semiconductor layer 140 formed on the insulating orientation layer 130. Specifically, the insulating orientation layer 130 can be controlled so that the first semiconductor layer 140 has c-axis orientation. "A layer having c-axis orientation" means that the c-axis of the crystal structure of the layer is oriented in a direction substantially perpendicular to the surface on which it is formed. As the insulating orientation layer 130, an insulating material having a hexagonal close-packed structure, a face-centered cubic structure, or a structure similar thereto can be used. Here, a hexagonal close-packed structure or a structure similar to a face-centered cubic structure includes a crystal structure in which the c-axis is not 90° with respect to the a-axis and b-axis. An insulating orientation layer 130 using an insulating material having a hexagonal close-packed structure or a structure similar thereto is oriented in the (0001) direction, i.e., in the c-axis direction, with respect to the amorphous substrate 110 (hereinafter referred to as the (0001) orientation of the hexagonal close-packed structure). Furthermore, the insulating orientation layer 130, which is made of a material having a face-centered cubic structure or a similar structure, is oriented in the (111) direction with respect to the amorphous substrate 110 (hereinafter referred to as the (111) orientation of the face-centered cubic structure). By having a (0001) orientation of a hexagonal close-packed structure or a (111) orientation of a face-centered cubic structure, crystal growth in the c-axis direction of the film deposited on the insulating orientation layer 130 is promoted, and the first semiconductor layer 140 on the insulating orientation layer 130 has c-axis orientation. As the insulating orientation layer 130, for example, aluminum nitride (AlN x ), aluminum oxide (AlO x ), lithium niobate (LiNbO), BiLaTiO, SrFeO, BiFeO, BaFeO, ZnFeO, PMnN-PZT, or bioapatite (BAp) can be used. The insulating orientation layer 130 can be deposited using any method (apparatus) such as sputtering or CVD.

[0033] The crystallinity of the first semiconductor layer 140 on the insulating orientation layer 130 is influenced by the surface state of the insulating orientation layer 130. Therefore, it is preferable that the insulating orientation layer 130 has a smooth surface with few irregularities. For example, the arithmetic mean roughness (Ra) of the surface of the insulating orientation layer 130 is preferably less than 2.3 nm. Also, the root mean square roughness (Rq) of the surface of the insulating orientation layer 130 is preferably less than 2.9 nm. When the surface roughness of the insulating orientation layer 130 meets these conditions, the first semiconductor layer 140 has a more crystallinity c-axis orientation. The film thickness of the insulating orientation layer 130 is preferably 50 nm or more.

[0034] One of the first semiconductor layer 140 and the second semiconductor layer 160 transports electrons and injects them into the light-emitting layer 150. That is, one of the first semiconductor layer 140 and the second semiconductor layer 160 is an n-type semiconductor layer. As the n-type semiconductor layer, for example, a silicon (Si)-doped gallium nitride film can be used. The other of the first semiconductor layer 140 and the second semiconductor layer 160 transports holes and injects them into the light-emitting layer 150. That is, the other of the first semiconductor layer 140 and the second semiconductor layer 160 is a p-type semiconductor layer. As the p-type semiconductor layer, for example, a magnesium (Mg)-doped gallium nitride film can be used. A silicon or magnesium-doped gallium nitride film can be deposited using sputtering.

[0035] The light-emitting layer 150 recombines injected electrons and holes to emit light. The light-emitting layer 150 has a multiple quantum well structure. As the light-emitting layer 150, for example, a laminated film in which indium gallium nitride (InGaN) films and gallium nitride films are alternately stacked can be used. The indium gallium nitride film or gallium nitride film can be deposited using sputtering.

[0036] Here, we will describe a method for depositing a gallium nitride film on the insulating orientation layer 130 using sputtering.

[0037] An amorphous substrate 110, on which an insulating orientation layer 130 is formed, is placed in a vacuum chamber facing a gallium nitride target. The composition ratio of gallium nitride in the gallium nitride target is preferably 0.7 to 2 gallium relative to nitrogen. In addition, nitrogen can be supplied to the vacuum chamber separately from the sputtering gas (argon or krypton, etc.). In this case, the composition ratio of gallium nitride in the gallium nitride target is preferably more gallium than nitrogen. For example, nitrogen can be supplied using a nitrogen radical source. The sputtering power supply may be a DC power supply, an RF power supply, or a pulsed DC power supply.

[0038] The amorphous substrate 110 in the vacuum chamber may be heated. For example, the amorphous substrate 110 can be heated from room temperature to less than 600°C. Preferably, it is 100°C or higher and more preferably 400°C or lower. This temperature is lower than the deposition temperature for MOCVD or HVPE and can be applied even to amorphous substrates 110 that have lower heat resistance than sapphire substrates.

[0039] After thoroughly evacuating the vacuum chamber, sputtering gas is supplied. A voltage is then applied between the amorphous substrate 110 and the gallium nitride target at a predetermined pressure to generate plasma and deposit a gallium nitride film.

[0040] The above describes a method for depositing gallium nitride films by sputtering, but the sputtering configuration or conditions can be modified as appropriate. Furthermore, by using a silicon-doped gallium nitride target or a magnesium-doped gallium nitride target instead of a gallium nitride target, n-type or p-type semiconductor films can be deposited. Additionally, by using an indium gallium nitride target or a gallium nitride target, a multilayer film in which indium gallium nitride films and gallium nitride films are alternately stacked can be deposited.

[0041] In the light-emitting device 100, the first semiconductor layer 140, the light-emitting layer 150, and the second semiconductor layer 160 each contain gallium nitride. The gallium nitride film of the first semiconductor layer 140 is directly deposited on the insulating orientation layer 130, but the gallium nitride films of the light-emitting layer 150 and the second semiconductor layer 160 are not directly deposited on the insulating orientation layer 130. However, because the first semiconductor layer 140 on the insulating orientation layer 130 has a highly crystalline c-axis orientation, the first semiconductor layer 140 functions similarly to the insulating orientation layer 130. Therefore, crystal growth in the c-axis direction of the gallium nitride film deposited on the first semiconductor layer 140 is promoted, and the light-emitting layer 150 on the first semiconductor layer 140 has c-axis orientation. Similarly, the second semiconductor layer 160 on the light-emitting layer 150 also has c-axis orientation.

[0042] One of the first electrode layer 170 and the second electrode layer 180 is an n-type electrode, and the other of the first electrode layer 170 and the second electrode layer 180 is a p-type electrode. The polarity of the electrodes of the first electrode layer 170 and the second electrode layer 180 is determined according to the first semiconductor layer 140 and the second semiconductor layer 160. As the n-type electrode, for example, a metal such as silver (Ag) or indium (In), or an alloy thereof, can be used. As the p-type electrode, for example, a metal such as palladium (Pd) or gold (Au), or an alloy thereof, can be used. These metals or alloys have a film thickness that does not transmit light emitted from the light-emitting layer 150 or light reflected by the semi-transparent reflective layer 120.

[0043] Although not shown in the diagram, a protective layer can be provided to cover the LED if necessary. A silicon nitride film can be used as the protective layer. Alternatively, a laminated film of, for example, a silicon oxide film and a silicon nitride film can be used as the protective layer.

[0044] As described above, the light-emitting device 100 according to this embodiment includes a region 300 having a microcavity structure. Therefore, the light-emitting device 100 has improved light extraction efficiency and less change in light extraction efficiency due to chromaticity changes. Furthermore, since the LEDs are formed using an amorphous substrate 110 in the light-emitting device 100, the manufacturing cost of the light-emitting device 100 can be reduced.

[0045] <Second Embodiment> Referring to Figures 4A to 5, another configuration of the light-emitting device 100 according to one embodiment of the present invention will be described. Note that in the following, the description of configurations similar to those described above may be omitted.

[0046] Figures 4A and 4B are schematic cross-sectional views showing the configuration of pixels 100A1-px and 100A2-px of a light-emitting device 100 according to one embodiment of the present invention, respectively. Figure 5 is a schematic cross-sectional view showing region 300A of Figure 4A or Figure 4B. As shown in Figure 4A, pixel 100A1-px includes an amorphous substrate 110, an insulating alignment layer 130A, a semi-transparent reflective layer 120A, a first semiconductor layer 140, a light-emitting layer 150, a second semiconductor layer 160, a first electrode layer 170, and a second electrode layer 180. That is, pixel 100A1-px is provided with an LED including the first semiconductor layer 140, the light-emitting layer 150, the second semiconductor layer 160, the first electrode layer 170, and the second electrode layer 180. The LED included in pixel 100A1-px has a so-called horizontal electrode structure in which a first electrode layer 170 and a second electrode layer 180 are provided on one side of the light-emitting layer 150. In pixel 100A1-px, the light emitted from the light-emitting layer 150 is extracted by passing through the amorphous substrate 110.

[0047] Furthermore, as shown in Figure 4B, the pixel 100A2-px includes an amorphous substrate 110, an insulating alignment layer 130A, a semi-transparent reflective layer 120A, a first semiconductor layer 140, a light-emitting layer 150, a second semiconductor layer 160, and a second electrode layer 180. As will be described in detail later, the semi-transparent reflective layer 120A can function as an electrode for the LED. Therefore, the pixel 100A2-px is provided with an LED that includes the semi-transparent reflective layer 120A, the first semiconductor layer 140, the light-emitting layer 150, the second semiconductor layer 160, and the second electrode layer 180. The LED included in the pixel 100A2-px has a so-called vertical electrode structure in which the semi-transparent reflective layer 120A, which functions as an electrode, is provided on one side of the light-emitting layer 150, and the second electrode layer 180 is provided on the other side of the light-emitting layer 150. In pixel 100A2-px, the light emitted from the light-emitting layer 150 is extracted by passing through the amorphous substrate 110.

[0048] Furthermore, both pixels 100A1-px and 100A2-px include a region 300A having a microcavity structure that repeatedly reflects between the semi-transparent reflective layer 120A and the second electrode layer 180.

[0049] In each of pixels 100A1-px and 100A2-px, the insulating alignment layer 130A is provided on the amorphous substrate 110. The semi-transparent reflective layer 120A is provided on the insulating alignment layer 130A. The first semiconductor layer 140 is provided on the semi-transparent reflective layer 120A. That is, the first semiconductor layer 140 is not provided in contact with the insulating alignment layer 130A. However, the thickness of the semi-transparent reflective layer 120A is small enough for light to pass through, and the insulating alignment layer 130A can control the crystallinity of the first semiconductor layer 140 via the semi-transparent reflective layer 120A. Therefore, the first semiconductor layer 140 provided on the semi-transparent reflective layer 120A has a highly crystalline c-axis orientation.

[0050] Furthermore, in pixel 100A2-px, the semi-transparent reflective layer 120A can be used as an electrode for the LED. If the resistance of the semi-transparent reflective layer 120A is high, the semi-transparent reflective layer 120A may contain a transparent conductive oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO). That is, at least a portion of the semi-transparent reflective layer 120A may be provided with a laminated film of a metal or alloy and a transparent conductive oxide. This makes it possible to reduce the resistance of the semi-transparent reflective layer 120A.

[0051] As described above, the light-emitting device 100 according to this embodiment includes a region 300A having a microcavity structure. Therefore, the light-emitting device 100 has improved light extraction efficiency and less change in light extraction efficiency due to chromaticity changes. Furthermore, since the LEDs are formed using an amorphous substrate 110 in the light-emitting device 100, the manufacturing cost of the light-emitting device 100 can be reduced.

[0052] <Third Embodiment> Referring to Figures 6 and 7, another configuration of the light-emitting device 100 according to one embodiment of the present invention will be described. Note that in the following, the description of configurations similar to those described above may be omitted.

[0053] Figure 6 is a schematic cross-sectional view showing the configuration of a pixel 100B-px of a light-emitting device 100 according to one embodiment of the present invention. As shown in Figure 6, the pixel 100B-px includes an amorphous substrate 110, a first insulating orientation layer 130B-1, a semi-transparent reflective layer 120B, a second insulating orientation layer 130B-2, a first semiconductor layer 140, a light-emitting layer 150, a second semiconductor layer 160, a first electrode layer 170, and a second electrode layer 180. That is, the pixel 100B-px is provided with an LED including the first semiconductor layer 140, the light-emitting layer 150, the second semiconductor layer 160, the first electrode layer 170, and the second electrode layer 180. The LED included in the pixel 100B-px has a so-called horizontal electrode structure in which the first electrode layer 170 and the second electrode layer 180 are provided on one side of the light-emitting layer 150. In a 100B-px pixel, the light emitted from the light-emitting layer 150 is extracted by passing through the amorphous substrate 110.

[0054] Furthermore, each pixel 100B-px includes a region 300B having a microcavity structure that repeatedly reflects between the semi-transparent reflective layer 120B and the second electrode layer 180.

[0055] In pixel 100B-px, the first insulating alignment layer 130B-1 is provided on the amorphous substrate 110. The semi-transparent reflective layer 120B is provided on the first insulating alignment layer 130B-1. The second insulating alignment layer 130B-2 is provided on the semi-transparent reflective layer 120B. The first semiconductor layer 140 is provided on the second insulating alignment layer 130B-2. When the first semiconductor layer 140 is provided on the semi-transparent reflective layer 120B, the c-axis orientation of the first semiconductor layer 140 may not be sufficient. In that case, the second insulating alignment layer 130B-2 is provided on the first semiconductor layer 140. As a result, the second insulating alignment layer 130B-2 can control the crystallinity of the first semiconductor layer 140, so that the first semiconductor layer 140 has highly crystalline c-axis orientation. Furthermore, since the second insulating orientation layer 130B-2 is located between the semi-transparent reflective layer 120B and the second electrode layer 180, the optical distance of the microcavity structure can also be adjusted by changing the film thickness of the second insulating orientation layer 130B-2. For example, the film thickness of the second insulating orientation layer 130B-2 can be greater than the film thickness of the first insulating orientation layer 130B-1.

[0056] As described above, the light-emitting device 100 according to this embodiment includes a region 300B having a microcavity structure. Therefore, the light-emitting device 100 has improved light extraction efficiency and less change in light extraction efficiency due to chromaticity changes. Furthermore, since the LED is formed using an amorphous substrate 110 in the light-emitting device 100, the manufacturing cost of the light-emitting device 100 can be reduced. <Fourth Embodiment> Referring to Figures 8 and 9, another configuration of the light-emitting device 100 according to one embodiment of the present invention will be described. Note that in the following, the description of configurations similar to those described above may be omitted.

[0057] Figure 8 is a schematic cross-sectional view showing the configuration of a pixel 100C-px of a light-emitting device 100 according to one embodiment of the present invention. As shown in Figure 8, the pixel 100C-px includes an amorphous substrate 110, an insulating alignment layer 130C, a conductive alignment layer 170C, a first semiconductor layer 140, an optical distance adjustment layer 190C, a light-emitting layer 150, a second semiconductor layer 160, a semi-transparent reflective layer 120C, and an insulating layer 200C. The conductive alignment layer 170C and the semi-transparent reflective layer 120C can function as the first electrode and second electrode of the LED, respectively. Therefore, the pixel 100C-px is provided with an LED including the conductive alignment layer 170C as the first electrode layer, the first semiconductor layer 140, the light-emitting layer 150, the second semiconductor layer 160, and the semi-transparent reflective layer 120C as the second electrode layer. The LED included in pixel 100C-px has a so-called vertical electrode structure, in which a conductive alignment layer 170C, which functions as a first electrode layer, is provided on one side of the light-emitting layer 150, and a semi-transparent reflective layer 120C, which functions as a second electrode layer, is provided on the other side of the light-emitting layer 150. In pixel 100C-px, the light emitted from the light-emitting layer 150 is extracted by passing through the insulating layer 200C.

[0058] The conductive alignment layer 170C can improve the crystallinity of the first semiconductor layer 140 formed on the conductive alignment layer 170C. Examples of conductive alignment layers 170C include titanium (Ti) and titanium nitride (TiN). x ), titanium dioxide (TiO x ), graphene, zinc oxide (ZnO), magnesium diboride (MgB2), aluminum (Al), silver (Ag), calcium (Ca), nickel (Ni), copper (Cu), strontium (Sr), rhodium (Rh), palladium (Pd), cerium (Ce), ytterbium (Yb), iridium (Ir), platinum (Pt), gold (Au), lead (Pb), actinium (Ac), thorium (Th), BiLaTiO, SrFeO, BiFeO, BaFeO, ZnFeO, or PMnN-PZT can be used. The conductive orientation layer 170C can be deposited using any method (apparatus) such as sputtering or CVD.

[0059] The insulating alignment layer 130C is provided on the amorphous substrate 110. The conductive alignment layer 170C is provided on the insulating alignment layer 130C. The first semiconductor layer 140 is provided on the conductive alignment layer 170C. The optical distance adjustment layer 190C is provided on the first semiconductor layer 140. The light-emitting layer 150 is provided on the optical distance adjustment layer 190C. The second semiconductor layer 160 is provided on the light-emitting layer 150. The semi-transparent reflective layer 120C is provided on the second semiconductor layer 160. The insulating layer 200C is provided on the semi-transparent reflective layer 120C.

[0060] Each of the insulating alignment layer 130C, conductive alignment layer 170C, first semiconductor layer 140, optical distance adjustment layer 190C, light-emitting layer 150, second semiconductor layer 160, semi-transparent reflective layer 120C, and insulating layer 200C may be provided in common to multiple pixels 100C-px. Although not shown, the conductive alignment layer 170C may be provided in an island-like manner within the pixels 100C-px, and the semi-transparent reflective layer 120C may be provided in common to multiple pixels 100C-px. Furthermore, although not shown, the conductive alignment layer 170C may extend in a first direction and be provided in common to multiple pixels 100C-px arranged in the first direction, and the semi-transparent reflective layer 120C may extend in a second direction and be provided in common to multiple pixels 100C-px arranged in the second direction.

[0061] The optical distance adjustment layer 190C can adjust the optical distance of the microcavity structure. Specifically, the film thickness of the optical distance adjustment layer 190C is increased as the wavelength of the extracted light increases. For example, gallium nitride can be used as the optical distance adjustment layer 190C, and it is preferable that it is the same material as the first semiconductor layer 140. In that case, the optical distance adjustment layer 190C can be considered a part of the first semiconductor layer 140. Therefore, the optical distance of the microcavity structure can be adjusted by changing the film thickness of the first semiconductor layer 140.

[0062] Although not shown in the diagram, the optical distance adjustment layer 190C may be provided between the conductive alignment layer 170C and the first semiconductor layer 140.

[0063] The insulating layer 200C allows light incident on the insulating layer 200C from the semi-transparent reflective layer 120C to be emitted to the outside. To improve the light extraction efficiency of the light-emitting device 100, it is preferable that the insulating layer 200C has a high refractive index. For example, aluminum nitride (AlN) can be used as the insulating layer 200C. The insulating layer 200C can be deposited using any method (apparatus) such as sputtering or CVD.

[0064] Although not shown in the diagram, the surface of the insulating layer 200C may have irregularities. This can further improve the light extraction efficiency of the light-emitting device 100.

[0065] In pixel 100C-px, the first semiconductor layer 140 is not provided in contact with the insulating alignment layer 130C, but is provided in contact with the conductive alignment layer 170C. Therefore, the first semiconductor layer 140 has a highly crystalline c-axis orientation. Moreover, the conductive alignment layer 170C provided on the insulating alignment layer 130C has a crystallinity that reflects the influence of the insulating alignment layer 130C, and the first semiconductor layer 140 provided on such a conductive alignment layer 170C is influenced by the insulating alignment layer 130C. Consequently, the first semiconductor layer 140 formed on the insulating alignment layer 130C and the conductive alignment layer 170C has an even more crystalline c-axis orientation.

[0066] As described above, the light-emitting device 100 according to this embodiment includes a region 300C having a microcavity structure. Therefore, the light-emitting device 100 has improved light extraction efficiency and less change in light extraction efficiency due to chromaticity changes. Furthermore, since the LEDs are formed using an amorphous substrate 110 in the light-emitting device 100, the manufacturing cost of the light-emitting device 100 can be reduced.

[0067] <Examples> Simulations were performed on the current efficiency and the change in chromaticity of the current efficiency for the microcavity structure in regions 300 to 300B of the light-emitting device 100 according to the first to third embodiments. The simulations were performed using Setfos (manufactured by Fluxim). In the simulations, the film thickness of the insulating orientation layer was varied, while the film thicknesses of other layers were kept constant.

[0068] [1. Example 1] Figure 10 is a graph showing the current efficiency with respect to the change in chromaticity (y-coordinate of the chromaticity coordinate) in the microcavity structure of region 300 shown in Figure 3. In the simulation of region 300 shown in Figure 3, the amorphous substrate 110, semi-transparent reflective layer 120, insulating orientation layer 130, and second electrode layer 180 used parameters for glass, magnesium silver (MgAg), aluminum nitride (AlN), and silver (Ag), respectively. The first semiconductor layer 140, light-emitting layer 150, and second semiconductor layer 160 all used parameters for gallium nitride (GaN). The film thicknesses of the amorphous substrate 110, semi-transparent reflective layer 120, first semiconductor layer 140, light-emitting layer 150, second semiconductor layer 160, and second electrode layer 180 were 0.5 mm, 15 nm, 10 nm, 20 nm, 20 nm, and 100 nm, respectively. Furthermore, the emission spectrum of the light-emitting layer 150 was determined to be a normal distribution with a peak at a wavelength of 460 nm.

[0069] [2. Example 2] Figure 11 is a graph showing the current efficiency with respect to the change in chromaticity (y-coordinate of the chromaticity coordinate) in the microcavity structure of region 300A shown in Figure 5. In the simulation of region 300A shown in Figure 5, the amorphous substrate 110, insulating orientation layer 130A, semi-transparent reflective layer 120A, and second electrode layer 180 used parameters for glass, aluminum nitride (AlN), magnesium silver (MgAg), and silver (Ag), respectively. The first semiconductor layer 140, light-emitting layer 150, and second semiconductor layer 160 all used parameters for gallium nitride (GaN). The film thicknesses of the amorphous substrate 110, semi-transparent reflective layer 120A, first semiconductor layer 140, light-emitting layer 150, second semiconductor layer 160, and second electrode layer 180 were 0.5 mm, 15 nm, 10 nm, 20 nm, 20 nm, and 100 nm, respectively. Furthermore, the emission spectrum of the light-emitting layer 150 was determined to be a normal distribution with a peak at a wavelength of 460 nm.

[0070] [3. Example 3] Figure 12 is a graph showing the current efficiency with respect to the change in chromaticity (y-coordinate of the chromaticity coordinate) in the microcavity structure of region 300B shown in Figure 7. In the simulation of region 300B shown in Figure 7, the amorphous substrate 110, the first insulating orientation layer 130B-1, the semi-transparent reflective layer 120B, the second insulating orientation layer 130B-2, and the second electrode layer 180 used the parameters of glass, aluminum nitride (AlN), magnesium silver (MgAg), aluminum nitride (AlN), and silver (Ag), respectively. The first semiconductor layer 140, the light-emitting layer 150, and the second semiconductor layer 160 all used the parameters of gallium nitride (GaN). Furthermore, the film thicknesses of the amorphous substrate 110, the first insulating orientation layer 130B-1, the semi-transparent reflective layer 120A, the first semiconductor layer 140, the light-emitting layer 150, the second semiconductor layer 160, and the second electrode layer 180 were 0.5 mm, 60 nm, 15 nm, 10 nm, 20 nm, 20 nm, and 100 nm, respectively. In addition, the emission spectrum of the light-emitting layer 150 was a normal distribution with a peak at a wavelength of 460 nm.

[0071] [4. Comparative Examples] FIG. 13 is a schematic cross-sectional view showing a region 500 of a comparative example having no microcavity structure. In the region 500, an insulating alignment layer 130, a first semiconductor layer 140, a light-emitting layer 150, a second semiconductor layer 160, and a second electrode layer 180 are sequentially provided on the amorphous substrate 110. In the region 500 of the comparative example, the light emitted from the light-emitting layer 150 is extracted through the amorphous substrate 110.

[0072] Further, FIG. 14 is a graph showing the current efficiency with respect to the change in chromaticity (y coordinate of the chromaticity coordinates) in the structure of the region 500 of the comparative example shown in FIG. 13. In the simulation of the region 500 shown in FIG. 13, the amorphous substrate 110, the insulating alignment layer 130, and the second electrode layer 180 used the parameters of glass, aluminum nitride (AlN), and silver (Ag), respectively. The first semiconductor layer 140, the light-emitting layer 150, and the second semiconductor layer 160 all used the parameters of gallium nitride (GaN). Also, the film thicknesses of the amorphous substrate 110, the first semiconductor layer 140, the light-emitting layer 150, the second semiconductor layer 160, and the second electrode layer 180 were 0.5 mm, 10 nm, 20 nm, 20 nm, and 100 nm, respectively. Further, the emission spectrum of the light-emitting layer 150 was a normal distribution with a peak wavelength of 460 nm.

[0073] [5. Results] The results of the simulation were compared between Examples 1 to 3 and the comparative example. The results of the simulation are shown in Tables 1 and 2. Specifically, Table 1 shows the current efficiency (η 0.04 ) at CIE-y (y coordinate of the chromaticity coordinates) = 0.04 and the current efficiency (η 0.05 ) at CIE-y = 0.05, and the rate of change of the current efficiency from CIE-y = 0.04 to CIE-y = 0.05 ((η 0.05 -η 0.04 ) / η 0.04Table 1 shows the difference between the examples normalized by the current efficiency of the comparative example ((η(example)-η(comparative example)) / η(comparative example)×100). From Table 1, it can be seen that the change in current efficiency with respect to chromaticity changes is smaller in Examples 1 to 3 compared to the comparative example. Also, from Table 2, it can be seen that the current efficiency is improved in Examples 1 to 3 compared to the comparative example. Therefore, in Examples 1 to 3, which have a microcavity structure, the light extraction efficiency is improved and the change in light extraction efficiency due to chromaticity changes is reduced.

[0074] [Table 1]

[0075] [Table 2]

[0076] <Fifth Embodiment> Referring to Figure 15, a light-emitting device forming substrate 10 according to one embodiment of the present invention will be described.

[0077] Figure 15 is a schematic diagram showing the configuration of a light-emitting device forming substrate 10 according to one embodiment of the present invention. The light-emitting device forming substrate 10 includes a plurality of light-emitting devices 100. That is, in the light-emitting device forming substrate 10, a plurality of light-emitting devices 100 are manufactured using one amorphous substrate 110. The amorphous substrate 110 is a so-called large-area substrate. In the light-emitting device forming substrate 10, a plurality of light-emitting devices 100 can be manufactured at once using a large-area substrate, so the manufacturing cost of the light-emitting devices 100 can be reduced.

[0078] The embodiments described above as examples of the present invention can be combined and implemented as appropriate, insofar as they do not contradict each other. Furthermore, any modifications made by those skilled in the art to each embodiment, such as adding, deleting, or changing components, or adding, omitting, or changing processes, are also included within the scope of the present invention, as long as they retain the essence of the present invention.

[0079] Any effects or benefits other than those brought about by the embodiments described above, if they are clear from the description herein or easily predictable to a person skilled in the art, are naturally considered to be brought about by the present invention. [Explanation of Symbols]

[0080] 10: Substrate for forming light-emitting device, 100: Light-emitting device, 100P: Pixel section, 100-px, 100A1-px, 100A2-px, 100B-px, 100C-px: Pixel, 100T: Terminal section, 100-t: Terminal, 110: Amorphous substrate, 120, 120A, 120B, 120C: Semitransparent reflective layer, 130, 130A, 130B-1, 130B-2, 130C: Insulating orientation layer, 140: First semiconductor layer, 150: Light-emitting layer, 160: Second semiconductor layer, 170: First electrode layer, 170C: Conductive orientation layer, 180: Second electrode layer, 190C: Optical distance adjustment layer, 200C: Insulating layer, 300, 300A, 300B, 300C: area, 500: area

Claims

1. The amorphous substrate includes a plurality of pixels arranged in a matrix in a first direction and a second direction intersecting the first direction, Each of the aforementioned plurality of pixels is The semi-transparent reflective layer on the amorphous substrate, A first insulating orientation layer on the semi-transparent reflective layer, The first semiconductor layer on the first insulating orientation layer, A light-emitting layer on the first semiconductor layer, A second semiconductor layer on the aforementioned light-emitting layer, The electrode layer on the second semiconductor layer, At least one of the semi-transparent reflective layer and the first insulating orientation layer is provided in common to the plurality of pixels. The first insulating orientation layer has a hexagonal close-packed structure, a face-centered cubic structure, or a structure equivalent to a hexagonal close-packed structure or a face-centered cubic structure. A light-emitting device in which each of the first semiconductor layer, the light-emitting layer, and the second semiconductor layer contains gallium nitride.

2. The amorphous substrate includes a plurality of pixels arranged in a matrix in a first direction and a second direction intersecting the first direction, Each of the aforementioned plurality of pixels is A first insulating orientation layer on the amorphous substrate, A semi-transparent reflective layer on the first insulating orientation layer, The first semiconductor layer on the semi-transparent reflective layer, A light-emitting layer on the first semiconductor layer, A second semiconductor layer on the aforementioned light-emitting layer, The electrode layer on the second semiconductor layer, At least one of the first insulating orientation layer and the semitransparent reflective layer is provided in common to the plurality of pixels. The first insulating orientation layer has a hexagonal close-packed structure, a face-centered cubic structure, or a structure equivalent to a hexagonal close-packed structure or a face-centered cubic structure. A light-emitting device in which each of the first semiconductor layer, the light-emitting layer, and the second semiconductor layer contains gallium nitride.

3. Each of the plurality of pixels further includes a second insulating orientation layer between the semitransparent reflective layer and the first semiconductor layer. The light-emitting device according to claim 2, wherein the second insulating orientation layer has a hexagonal close-packed structure, a face-centered cubic structure, or a structure equivalent to a hexagonal close-packed structure or a face-centered cubic structure.

4. The light-emitting apparatus according to claim 3, wherein the thickness of the second insulating orientation layer is greater than the thickness of the first insulating orientation layer.

5. The amorphous substrate includes a plurality of pixels arranged in a matrix in a first direction and a second direction intersecting the first direction, Each of the aforementioned plurality of pixels is A first insulating orientation layer on the amorphous substrate, The electrode layer on the first insulating orientation layer, The first semiconductor layer on the electrode layer, A light-emitting layer on the first semiconductor layer, A second semiconductor layer on the aforementioned light-emitting layer, The second semiconductor layer includes a semi-transparent reflective layer, At least one of the first insulating orientation layer and the semitransparent reflective layer is provided in common to the plurality of pixels. The first insulating orientation layer has a hexagonal close-packed structure, a face-centered cubic structure, or a structure equivalent to a hexagonal close-packed structure or a face-centered cubic structure. A light-emitting device in which each of the first semiconductor layer, the light-emitting layer, and the second semiconductor layer contains gallium nitride.

6. The light-emitting device according to claim 5, wherein each of the plurality of pixels further includes an insulating layer on the semitransparent reflective layer.

7. Each of the plurality of pixels further includes an optical distance adjustment layer between the first semiconductor layer and the light-emitting layer. The light-emitting apparatus according to any one of claims 1 to 6, wherein the optical distance adjustment layer comprises gallium nitride.

8. The light-emitting apparatus according to any one of claims 1 to 6, wherein the first insulating orientation layer comprises at least one selected from aluminum nitride and aluminum oxide.

9. The light-emitting apparatus according to any one of claims 1 to 6, wherein the semi-transparent reflective layer comprises at least one selected from silver and magnesium.

10. The light-emitting device according to any one of claims 1 to 6, wherein the amorphous substrate is an amorphous glass substrate.

11. A plurality of light-emitting devices according to any one of claims 1 to 6, The amorphous substrate is a single substrate common to the plurality of light-emitting devices, which is a light-emitting device forming substrate.

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