Light-emitting device and method for manufacturing same

Abstract

A light-emitting device according to the present invention comprises a first amorphous substrate and a red light-emitting element including a red light-emitting layer on the first amorphous substrate. The red light-emitting layer includes at least one of an arsenide semiconductor or a phosphide semiconductor and is deposited by sputtering. A method for manufacturing the light-emitting device comprises forming a first buffer layer on a first amorphous substrate, and forming a red light-emitting element including a red light-emitting layer on the first buffer layer. The red light-emitting layer is deposited by sputtering and includes at least one of an arsenide semiconductor or a phosphide semiconductor.

Description

Light-emitting device and method for manufacturing the same

[0001] One embodiment of the present invention relates to a red light-emitting element provided on an amorphous substrate and a method for manufacturing the same.

[0002] As a next-generation display technology, development is underway on so-called microLED displays, which arrange tiny microLEDs within a matrix of pixels. MicroLEDs have a similar structure to conventional LEDs, containing compound semiconductors such as gallium (Ga) or indium (In). Therefore, microLED displays are expected to be a next-generation display with high reliability, high brightness, and high contrast.

[0003] Micro-LEDs used in micro-LED displays are fabricated using a sapphire substrate separate from the circuit board (also called a backplane or TFT substrate). Therefore, in micro-LED displays, it is necessary to place the fabricated micro-LEDs on the circuit board. One method of placing micro-LEDs is to transfer them to the circuit board using a carrier substrate (see, for example, Patent Document 1 or Patent Document 2).

[0004] Incidentally, a method for depositing gallium nitride by metal-organic vapor deposition (MOCVD) on a buffer layer on a glass substrate has been disclosed (for example, Patent Document 3). In other words, technological development of gallium nitride using a glass substrate instead of a sapphire substrate is underway. However, red LEDs containing gallium nitride as the light-emitting layer have lower luminous efficiency than red LEDs containing gallium arsenide as the light-emitting layer.

[0005] U.S. Patent Application Publication No. 2016 / 0240516, U.S. Patent Application Publication No. 2017 / 0047306, Japanese Patent Publication No. 2000-124140

[0006] One embodiment of the present invention aims to provide a light-emitting device and a method for manufacturing the same, which includes a red light-emitting element having high luminescence efficiency, comprising a light-emitting layer formed on an amorphous substrate by sputtering.

[0007] A light-emitting device according to one embodiment of the present invention includes a first amorphous substrate and a red light-emitting element including a red light-emitting layer on the first amorphous substrate, wherein the red light-emitting layer includes at least one of an arsenide semiconductor and a phosphide semiconductor, and the red light-emitting layer is formed by sputtering.

[0008] A method for manufacturing a light-emitting device according to one embodiment of the present invention includes forming a first buffer layer on a first amorphous substrate, and forming a red light-emitting element including a red light-emitting layer on the first buffer layer, wherein the red light-emitting layer is formed by sputtering, and the red light-emitting layer includes at least one of an arsenide semiconductor and a phosphide semiconductor.

[0009] This is a schematic cross-sectional view showing the configuration of a light-emitting device according to one embodiment of the present invention. This is a schematic plan view showing the configuration of a circuit board for a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view showing the configuration of a light-emitting element for a light-emitting device according to one embodiment of the present invention. This is a circuit diagram showing the configuration of a pixel circuit that controls a light-emitting element in a light-emitting device according to one embodiment of the present invention. This is a flowchart illustrating the manufacturing method of a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the manufacturing method of a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the manufacturing method of a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the manufacturing method of a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the manufacturing method of a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the configuration of a light-emitting device according to one embodiment of the present invention. This is a flowchart illustrating the manufacturing method of a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the manufacturing method of a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the configuration of a light-emitting device according to one embodiment of the present invention. This is a flowchart illustrating the manufacturing method of a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the manufacturing method of a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the manufacturing method of a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the configuration of a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view showing the configuration of a light-emitting device according to one embodiment of the present invention. This is a flowchart illustrating the manufacturing method of a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view showing the configuration of a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view showing the configuration of a light-emitting device according to one embodiment of the present invention.This is a flowchart illustrating a method for manufacturing a light-emitting device according to one embodiment of the present invention. This is a schematic cross-sectional view

[0010] Embodiments of the present invention will be described below with reference to the drawings. The following disclosure is merely an example. Configurations that a person skilled in the art could easily conceive by appropriately modifying the configuration of the embodiments while maintaining the spirit of the invention are naturally included within the scope of the present invention. In order to make the explanation clearer, the drawings may schematically represent the width, thickness, and shape of the components compared to the actual embodiments. However, the illustrated shapes are merely examples and do not limit the interpretation of the present invention. In this specification and drawings, components similar to those described above with respect to previously shown figures are denoted by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0011] 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 through C, unless otherwise explicitly stated. Furthermore, these expressions do not exclude cases where α includes other components.

[0012] In this specification and other documents, for the sake of explanation, the terms "up" or "above" or "down" or "below" are used, but the hierarchical relationship may be reversed depending on the constituent element being used as a reference.

[0013] In this specification, "compound semiconductor" refers to a semiconductor containing Group 13 elements such as aluminum (Al), gallium (Ga), or indium (In), and Group 15 elements such as nitrogen (N), phosphorus (P), or arsenic (As). For example, "compound semiconductor" includes, but is not limited to, gallium nitride (GaN), aluminum gallium nitride (AlGaN), gallium phosphide (GaP), aluminum indium phosphide (AlInP), gallium arsenide (GaAs), or aluminum gallium arsenide (AlGaAs).

[0014] In this specification, "nitride semiconductor" refers to a compound semiconductor containing nitrogen as its main constituent element. For example, "nitride semiconductors" include, but are not limited to, gallium nitride (GaN) or aluminum gallium nitride (AlGaN). Also, in this specification, "phosphide semiconductor" refers to a compound semiconductor containing phosphorus as its main constituent element. For example, "phosphide semiconductors" include, but are not limited to, gallium phosphide (GaP) or aluminum indium phosphide (AlInP). Also, in this specification, "arsenide semiconductor" refers to a compound semiconductor containing arsenic as its main element. For example, "arsenide semiconductors" include, but are not limited to, gallium arsenide (GaAs) or aluminum gallium arsenide (AlGaAs). Note that "nitride semiconductors," "phosphide semiconductors," and "arsenide semiconductors" may contain impurity elements in addition to their main constituent elements. For example, gallium indium nitrogen arsenide (GaInNAs) is an arsenide semiconductor containing nitrogen as an impurity element.

[0015] In this specification, "light-emitting device" refers to any device that includes a light-emitting element. For example, "light-emitting device" includes lighting devices that illuminate a specific location, and display devices that display visual images or videos.

[0016] The following embodiments can be combined with each other, provided that no technical inconsistencies arise.

[0017] <First Embodiment> A light-emitting device 10 according to one embodiment of the present invention will be described with reference to Figures 1 to 10. In this embodiment, the light-emitting device 10 will be described as a display device, but the light-emitting device 10 is not limited to a display device.

[0018] [1. Configuration of the Light-Emitting Device 10] [1-1. Overview of the Light-Emitting Device 10] Figure 1 is a schematic cross-sectional view showing the configuration of a light-emitting device 10 according to one embodiment of the present invention.

[0019] As shown in Figure 1, the light-emitting device 10 includes a circuit board 100, a blue light-emitting element 200B, a green light-emitting element 200G, a red light-emitting element 200R, and buffer layers 280B, 280G, and 280R. The light-emitting device 10 has a structure in which the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R are arranged on the circuit board 100. The blue light-emitting element 200B is provided on the circuit board 100 with the buffer layer 280B in between. That is, the buffer layer 280B is provided between the circuit board 100 and the blue light-emitting element 200B. The green light-emitting element 200G is provided on the circuit board 100 with the buffer layer 280G in between. That is, the buffer layer 280G is provided between the circuit board 100 and the green light-emitting element 200G. The red light-emitting element 200R is provided on the circuit board 100 with the buffer layer 280R in between. In other words, the buffer layer 280R is provided between the circuit board 100 and the red light-emitting element 200R. The buffer layers 280B, 280G, and 280R are in contact with the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R, respectively. The circuit board 100 is a substrate on which various circuits (hereinafter sometimes referred to as "control circuits") for controlling the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R are formed. Each of the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R is a so-called light-emitting diode (LED). The blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R are electrically connected to the control circuits in the circuit board 100, and the light-emitting characteristics of each of the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R (e.g., ON or OFF of light emission, and brightness, etc.) are controlled by the control circuits. Although Figure 1 shows one blue light-emitting element 200B, one green light-emitting element 200G, and one red light-emitting element 200R, multiple blue light-emitting elements 200B, multiple green light-emitting elements 200G, and multiple red light-emitting elements 200R are arranged on the circuit board 100.

[0020] In the following description, the configurations of the circuit board 100 and the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R will be explained. However, when the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R are not specifically distinguished, they may be described as the light-emitting element 200.

[0021] [1-2. Configuration of the Circuit Board 100] Figure 2 is a schematic plan view showing the configuration of the circuit board 100 of a light-emitting device 10 according to one embodiment of the present invention.

[0022] As shown in Figure 2, the circuit board 100 has a display unit 110a, a drive circuit unit 110b, and a terminal unit 110c on an amorphous substrate 110. The display unit 110a is located in the center of the amorphous substrate 110. The drive circuit unit 110b is located outside the display unit 110a and can control the display unit 110a. For example, the drive circuit unit 110b includes a scanning drive circuit. The terminal unit 110c is located at the edge of the amorphous substrate 110 and includes a terminal 120 that is electrically connected to an external device. Specifically, a flexible printed circuit board (FPC) is electrically connected to the terminal 120, and signals or power can be supplied to the display unit 110a, the drive circuit unit 110b, or the light-emitting element 200 of the circuit board 100 via the flexible printed circuit board (FPC). A driver IC for controlling the display unit 110a or the drive circuit unit 110b may be provided on the flexible printed circuit board (FPC).

[0023] As the amorphous substrate 110, for example, a glass substrate or a resin substrate such as polyimide resin can be used. If the amorphous substrate 110 is a glass substrate that can be made into a large area, a light-emitting device 10 with a large area can be manufactured.

[0024] Here, we will describe the glass substrate used in the light-emitting device 10. The upper limit of the thermal expansion coefficient of the glass substrate is 4.2 × 10⁻⁶. －６ Less than / K, preferably 4.0 × 10 －６ It is less than / K. The lower limit of the thermal expansion coefficient of the glass substrate is 3.0 × 10⁻⁶. －６ / K exceeds, preferably 3.5 × 10－６ The temperature exceeds / K. The buffer layers 280B, 280G, and 280R, and the light-emitting element 200 are formed at a temperature of less than 650°C. Therefore, it is preferable that the glass substrate has heat resistance at a temperature of at least 650°C. The lower limit of the glass transition temperature of the glass substrate is 650°C or higher, preferably 720°C or higher. The upper limit of the glass transition temperature of the glass substrate is 900°C or lower, preferably 810°C or lower. For similar reasons, the lower limit of the softening point of the glass substrate is 900°C or higher, preferably 950°C or higher. The upper limit of the softening point of the glass substrate is 1150°C or lower, preferably 1050°C or lower.

[0025] Furthermore, the glass material used as the glass substrate preferably has a low alkali metal content to prevent contamination of the light-emitting element 200. For example, the alkali metal content in the glass substrate is 0.1% by mass or less. As the glass substrate, for example, an amorphous glass material composed of aluminoborosilicate glass or aluminosilicate glass is used. Amorphous glass substrates are used in liquid crystal displays and organic electroluminescent (organic EL) displays, and large-area glass substrates called mother glass are available on the market. Therefore, by using a highly versatile glass substrate as the substrate on which the light-emitting element 200 is formed, the light-emitting element 200 can be manufactured at low cost using a large-area substrate.

[0026] The thickness of the glass substrate is not particularly limited, but it is preferable that it be sufficiently greater than the thickness of each of the buffer layers 280B, 280G, and 280R in order to reduce warping of the glass substrate. For example, the thickness of the glass substrate is 0.5 mm or more and 1.0 mm or less. Although not shown in the figures, an underlayer may be formed on the glass substrate to prevent the diffusion of impurities (e.g., water or sodium (Na)) from the glass substrate. As an underlayer, for example, silicon oxide (SiO ｘ ) or silicon nitride (SiN ｘ ) and the like can be used. The underlayer may be a single film or a multilayer film.

[0027] The display unit 110a can display an image or video and includes a plurality of pixels 130 arranged in a matrix. However, the plurality of pixels 130 may be arranged not only in a matrix but also in a staggered pattern. Each pixel 130 includes a pixel circuit consisting of a light-emitting element 200 arranged on a circuit board 100 and a control circuit electrically connected to the light-emitting element 200. Specifically, one pixel 130 contains one blue light-emitting element 200B, one green light-emitting element 200G, and one red light-emitting element 200R. Figure 1 can be said to illustrate the configuration of one pixel 130 of the light-emitting device 10. In each of the plurality of pixels 130, the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R are controlled by the control circuit, thereby enabling the display unit 110a to display an image or video.

[0028] [1-3. Configuration of the Light-Emitting Element 200] Figure 3 is a schematic cross-sectional view showing the configuration of the light-emitting element 200 of the light-emitting device 10 according to one embodiment of the present invention. The structure of the light-emitting element 200 shown in Figure 3 is a basic structure common to the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R.

[0029] As shown in Figure 3, the light-emitting element 200 includes an n-type semiconductor layer 220, a light-emitting layer 230, a p-type semiconductor layer 240, a p-type electrode 250, and an n-type electrode 260. The light-emitting layer 230 is provided on the n-type semiconductor layer 220. The p-type semiconductor layer 240 is provided on the light-emitting layer 230. The p-type electrode 250 is provided on the p-type semiconductor layer 240 and is electrically connected to the p-type semiconductor layer 240. The n-type electrode 260 is provided on the n-type semiconductor layer 220 that is exposed from the light-emitting layer 230 and the p-type semiconductor layer 240 (in other words, within the recess of the n-type semiconductor layer 220) and is electrically connected to the n-type semiconductor layer 220.

[0030] Each of the n-type semiconductor layer 220, the light-emitting layer 230, and the p-type semiconductor layer 240 contains a compound semiconductor. In the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R, the compound semiconductors contained in the n-type semiconductor layer 220, the light-emitting layer 230, and the p-type semiconductor layer 240 may be different.

[0031] The n-type semiconductor layer 220 has electronic conductivity and can transport electrons supplied from the n-type electrode 260 to the light-emitting layer 230. The n-type semiconductor layer 220 includes a compound semiconductor doped with impurities such as silicon (Si) or germanium (Ge) (hereinafter referred to as "n-type impurities"). For the n-type semiconductor layer 220 of the blue light-emitting element 200B and the green light-emitting element 200G, nitride semiconductors such as gallium nitride (GaN) or aluminum gallium nitride (AlGaN) can be used. For the n-type semiconductor layer 220 of the red light-emitting element 200R, arsenide semiconductors or phosphide semiconductors such as gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), aluminum gallium arsenide (GaAlAs), or aluminum indium phosphide (AlInP) can be used.

[0032] The light-emitting layer 230 can emit light when electrons transported from the n-type semiconductor layer 220 and holes transported from the p-type semiconductor layer 240 are recombined. The blue light-emitting element 200B includes a light-emitting layer 230 (blue light-emitting layer) that emits blue light. The green light-emitting element 200G includes a light-emitting layer 230 (green light-emitting layer) that emits green light. The red light-emitting element 200R includes a light-emitting layer 230 (red light-emitting layer) that emits red light. The light-emitting layer 230 of the blue light-emitting element 200B and the green light-emitting element 200G has a multiple quantum well (MQW) structure in which gallium nitride (GaN) and indium gallium nitride (InGaN) are alternately stacked. As the light-emitting layer 230 of the red light-emitting element 200R, an arsenide semiconductor or phosphide semiconductor such as aluminum gallium arsenide (AlGaAs), gallium indium nitrogen arsenide (GaInNAs), gallium indium arsenide (GaInAs), or aluminum gallium indium phosphide (AlGaInP) can be used.

[0033] The p-type semiconductor layer 240 has hole conductivity and is capable of transporting holes supplied from the p-type electrode 250 to the light-emitting layer 230. The p-type semiconductor layer 240 includes a nitride semiconductor doped with an impurity such as magnesium (Mg) (hereinafter referred to as "p-type impurity"). A nitride semiconductor such as gallium nitride (GaN) or aluminum gallium nitride (AlGaN) can be used as the p-type semiconductor layer 240 of the blue light-emitting element 200B and the green light-emitting element 200G. As the p-type semiconductor layer 240 of the red light-emitting element 200R, an arsenide semiconductor or phosphide semiconductor such as gallium arsenide, aluminum gallium arsenide (AlGaAs), gallium aluminum arsenide (GaAlAs), or aluminum indium phosphide (AlInP) can be used.

[0034] The p-type electrode 250 is electrically connected to an electrode of a pixel circuit on the circuit board 100 (not shown in the figure), and can supply holes to the p-type semiconductor layer 240. As the p-type electrode 250, for example, a metal such as palladium (Pd) or gold (Au) can be used.

[0035] The n-type electrode 260 is electrically connected to an electrode of a pixel circuit on the circuit board 100 (not shown in the figure), and can supply electrons to the n-type semiconductor layer 220. As the n-type electrode 260, for example, a metal such as indium (In) can be used.

[0036] Heretofore, the structure of the light-emitting element 200 has been described with reference to FIG. 3. The structure of the light-emitting element 200 shown in FIG. 3 is an example, and the structure of the light-emitting element 200 is not limited thereto. The light-emitting element 200 shown in FIG. 3 has a so-called horizontal electrode structure in which the p-type electrode 250 and the n-type electrode 260 do not overlap in the thickness direction. However, the light-emitting element 200 of the light-emitting device 10 may have a so-called vertical electrode structure in which the p-type electrode and the n-type electrode overlap with the light-emitting layer interposed therebetween in the thickness direction. Furthermore, the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element may have the same structure or different structures. Furthermore, although not shown in FIG. 3, an insulating layer including an undoped compound semiconductor may be provided below the n-type semiconductor layer 220.

[0037] [1-4. Configuration of Pixel Circuit] FIG. 4 is a circuit diagram showing a configuration of a pixel circuit that controls the light emitting element 200 in the light emitting device 10 according to an embodiment of the present invention.

[0038] FIG. 4 shows, as a pixel circuit for driving the light emitting element 200, a first transistor Tr1, a second transistor Tr2, the light emitting element 200, and a capacitive element Cap. That is, the first transistor Tr1, the second transistor Tr2, the light emitting element 200, and the capacitive element Cap are provided in the pixel 130.

[0039] The first transistor Tr1 can function as a selection transistor. That is, the conduction state of the first transistor Tr1 is controlled by the scanning line GL. In the first transistor Tr1, the gate, the source, and the drain are electrically connected to the scanning line GL, the signal line SL, and the gate of the second transistor Tr2, respectively.

[0040] The second transistor Tr2 can function as a driving transistor. That is, the second transistor Tr2 controls the emission luminance of the light emitting element 200. In the second transistor Tr2, the gate, the source, and the drain are electrically connected to the source of the first transistor Tr1, the power supply line PVH, and the anode (p-type electrode 250) of the light emitting element 200, respectively. A predetermined potential (Vcc) is supplied to the power supply line PVH.

[0041] One of the capacitive electrodes of the capacitive element Cap is electrically connected to the gate of the second transistor Tr2 and the drain of the first transistor Tr1. The other capacitive electrode of the capacitive element Cap is electrically connected to the power supply line PVH.

[0042] The anode of the light emitting element 200 is electrically connected to the drain of the second transistor Tr2. Further, the cathode (n-type electrode 260) of the light emitting element 200 is electrically connected to a reference power supply line PVL to which a reference potential (Vss) is supplied.

[0043] The light-emitting element 200, positioned on the pixel 130, is controlled by signals input to the scan line GL and signal line SL to either turn the light emission on or off, or to control the emission time or brightness.

[0044] The pixel circuit shown in Figure 4 is an example of a pixel circuit for controlling the light-emitting element 200, and the pixel circuit is not limited to this. The pixel circuit only needs to have a configuration that can control the light-emitting element 200 arranged within the pixel 130.

[0045] [2. Method for Manufacturing the Light-Emitting Device 10] Next, the method for manufacturing the light-emitting device 10 will be described with reference to Figures 5 to 10.

[0046] Figure 5 is a flowchart illustrating a method for manufacturing a light-emitting device 10 according to one embodiment of the present invention. Figures 6 to 10 are schematic cross-sectional views illustrating a method for manufacturing a light-emitting device 10 according to one embodiment of the present invention.

[0047] As shown in Figure 5, the manufacturing method of the light-emitting device 10 broadly includes the steps of forming a control circuit on an amorphous substrate 110 (step S100), forming a blue light-emitting element 200B (step S200), forming a green light-emitting element 200G (step S300), and forming a red light-emitting element 200R (step S400). Step S100 is the step of manufacturing a so-called circuit board 100. Since the circuit board 100 can be manufactured using conventional manufacturing methods, the explanation of step S100 will be omitted here. In the following, steps S200, S300, and S400 will be explained with reference to Figures 6 to 10 as appropriate.

[0048] Step S200 includes steps S210 and S220.

[0049] In step S210, a buffer layer 280B is formed on the circuit board 100 (see Figure 6). The buffer layer 280B is deposited on the circuit board 100 at a temperature of less than 650°C using sputtering or CVD, and is formed into a predetermined pattern shape using photolithography.

[0050] The buffer layer 280B can control the crystal orientation of a nitride semiconductor formed by sputtering on the buffer layer 280B and improve the crystallinity of the nitride semiconductor. Specifically, the buffer layer 280B can control the c-axis of the nitride semiconductor formed on the buffer layer 280B to grow in the thickness direction. A nitride semiconductor having a hexagonal close-packed structure grows in the c-axis direction to minimize surface energy, and forming the nitride semiconductor on the buffer layer 280B promotes crystal growth of the nitride semiconductor in the c-axis direction. As a result, the nitride semiconductor on the buffer layer 280B has c-axis orientation.

[0051] As the buffer layer 280B, a material having a hexagonal close-packed structure, a face-centered cubic structure, or a structure equivalent thereto can be used. Here, the structure equivalent to a hexagonal close-packed structure or a face-centered cubic structure includes a crystal structure in which the c-axis is not 90° with respect to the a-axis and the b-axis. When the buffer layer 280B has the above structure, the nitride semiconductor formed on the buffer layer 280B has high c-axis-oriented crystallinity.

[0052] For example, as the buffer layer 280B, titanium (Ti), zirconium (Zr), 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), (Th), silicon (Si), germanium (Ge), or alloys thereof, titanium nitride (TiN ｘ ), titanium oxide (TiO ｘ ), graphene, zinc oxide (ZnO), magnesium diboride (MgB ２ ), aluminum nitride (AlN), aluminum oxide (Al ２ O ３), lithium niobate (LiNbO), BiLaTiO, SrFeO, BiFeO, BaFeO, ZnFeO, PMnN-PZT, or bioapatite (BAp) can be used. In particular, it is preferable to use titanium, zirconium, silicon, or zinc oxide as the buffer layer 280B. The thickness of the buffer layer 280B is not particularly limited, but for example, it is 10 nm to 500 nm.

[0053] In step S220, a blue light-emitting element 200B is formed on the buffer layer 280B (see Figure 7). Specifically, an n-type semiconductor layer 220, an emissive layer 230, and a p-type semiconductor layer 240 are sequentially deposited on the buffer layer 280B using sputtering, and a predetermined pattern shape is formed using photolithography. The presence of the buffer layer 280B not only improves the crystallinity of the n-type semiconductor layer 220 in contact with the buffer layer 280B, but also improves the crystallinity of the emissive layer 230 and the p-type semiconductor layer 240 on the n-type semiconductor layer 220. For example, the n-type semiconductor layer 220 and the p-type semiconductor layer 240 can be deposited using gallium nitride containing n-type impurities and gallium nitride containing p-type impurities as sputtering targets, respectively. The emissive layer 230 is formed by alternately depositing gallium nitride and indium gallium nitride using gallium nitride and indium gallium nitride as sputtering targets. Furthermore, a p-type electrode 250 and an n-type electrode 260 are formed so as to be in contact with the p-type semiconductor layer 240 and the n-type semiconductor layer 220, respectively. As a result, a blue light-emitting element 200B is formed on the buffer layer 280B.

[0054] Furthermore, the n-type semiconductor layer 220 and the p-type semiconductor layer 240 may be heat-treated before forming the p-type electrode 250 and the n-type electrode 260. This improves the conductivity of the n-type semiconductor layer 220 and the p-type semiconductor layer 240.

[0055] Step S300 includes steps S310 and S320.

[0056] In step S310, a buffer layer 280G is formed on the circuit board 100 (see Figure 8). The buffer layer 280G is deposited on the circuit board 100 at a temperature of less than 650°C using sputtering or CVD, and is formed into a predetermined pattern shape using photolithography.

[0057] The buffer layer 280G has the same function as the buffer layer 280B. That is, the buffer layer 280G can control the crystal orientation of the nitride semiconductor film deposited on the buffer layer 280G using sputtering, thereby improving the crystallinity of the nitride semiconductor. The buffer layer 280G may be made of the same material as the buffer layer 280B, or it may be made of a different material. It is preferable to use titanium, zirconium, silicon, or zinc oxide as the buffer layer 280G. The thickness of the buffer layer 280G is not particularly limited, but for example, it is between 10 nm and 500 nm.

[0058] In step S320, a green light-emitting element 200G is formed on the buffer layer 280G (see Figure 9). The green light-emitting element 200G can be formed using the same method as the blue light-emitting element 200B, so its description is omitted here.

[0059] Step S400 includes steps S410 and S420.

[0060] In step S410, a buffer layer 280R is formed on the circuit board 100 (see Figure 10). The buffer layer 280R is deposited on the circuit board 100 at a temperature of less than 650°C using sputtering or CVD, and is formed into a predetermined pattern shape using photolithography.

[0061] The buffer layer 280R can control the crystal orientation of the phosphide semiconductor or arsenide semiconductor deposited on the buffer layer 280R using sputtering, thereby improving the crystallinity of the phosphide semiconductor or arsenide semiconductor. For example, the buffer layer 280R can be titanium (Ti), zirconium (Zr), 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), (Th), silicon (Si), germanium (Ge), or alloys thereof, titanium nitride (TiN) ｘ ), titanium oxide (TiO ｘ ), graphene, zinc oxide (ZnO), magnesium diboride (MgB ２ ), aluminum nitride (AlN), aluminum oxide (Al ２ O ３ Materials such as lithium niobate (LiNbO), BiLaTiO, SrFeO, BiFeO, BaFeO, ZnFeO, PMnN-PZT, or bioapatite (BAp) can be used. In particular, silicon, germanium, or graphene is preferred as the buffer layer 280R. The buffer layer 280R may be made of the same material as buffer layers 280B and 280G, or it may be made of a different material. The thickness of the buffer layer 280R is not particularly limited, but for example, it is 10 nm to 500 nm.

[0062] In step S420, a red light-emitting element 200R is formed on the buffer layer 280R. Although the red light-emitting element 200R is made of a different material than the blue light-emitting element 200B, it can be formed using the same method as the blue light-emitting element 200B, so its description is omitted here. Although a detailed explanation is omitted, the manufacturing method of the light-emitting device 10 further includes the step of electrically connecting the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R to the control circuit in the pixel 130. This manufactures the light-emitting device 10 shown in Figure 1.

[0063] Although steps S200, S300, and S400 have been described above, steps S200, S300, and S300 may be performed in this order, or their order may be reversed. Furthermore, some steps may be omitted or combined. For example, when buffer layer 280B and buffer layer 280G are made of the same material, buffer layer 280G may be formed in step S210, as well as buffer layer 280B. Also, step S100 may be performed after steps S200, S300, and S300. That is, the light-emitting element 200 may be formed on the substrate first, and then the control circuit may be laminated on top of the light-emitting element 200.

[0064] According to the light-emitting device 10 of this embodiment, by adjusting the materials of the buffer layers 280B, 280G, and 280R formed on the circuit board 100 including the amorphous substrate 110, not only blue light-emitting elements 200B and green light-emitting elements 200G containing nitride semiconductors, but also red light-emitting elements 200R containing arsenide semiconductors or phosphide semiconductors can be directly formed on the circuit board 100. The red light-emitting element 200R containing phosphide semiconductors or arsenide semiconductors as the light-emitting layer 230 has higher luminescence efficiency than the red light-emitting element containing nitride semiconductors as the light-emitting layer. Therefore, the light-emitting device 10 can be manufactured at low cost using an amorphous substrate and can have high luminescence efficiency not only for blue and green light emission, but also for red light emission.

[0065] <Second Embodiment> A light-emitting device 10A, which is different from the light-emitting device 10, will be described with reference to Figures 11 to 15. In the following, the description of configurations similar to those in the first embodiment may be omitted.

[0066] [1. Configuration of Light-Emitting Device 10A] Figure 11 is a schematic cross-sectional view showing the configuration of a light-emitting device 10A according to one embodiment of the present invention.

[0067] As shown in Figure 11, the light-emitting device 10A includes a circuit board 100, a blue light-emitting element 200B, a green light-emitting element 200G, a red light-emitting element 200R, buffer layers 280B, 280G, and 280R, and an amorphous substrate 310. The circuit board 100 and the amorphous substrate 310 are arranged facing each other, and the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R are arranged between the circuit board 100 and the amorphous substrate 310. The blue light-emitting element 200B is provided on the circuit board 100 with the buffer layer 280B in between. The green light-emitting element 200G is also provided on the circuit board 100 with the buffer layer 280G in between. That is, the blue light-emitting element 200B and the green light-emitting element 200G are provided on the amorphous substrate 310 side of the buffer layers 280B and 280G. On the other hand, the red light-emitting element 200R is provided on the amorphous substrate 310 with a buffer layer 280R in between. In other words, the buffer layer 280R is provided on the side opposite to the circuit board 100 with the red light-emitting element 200R in between. That is, the red light-emitting element 200R is provided between the circuit board 100 and the buffer layer 280R, and is provided on the circuit board 100 side of the buffer layer 280R. The buffer layers 280B, 280G, and 280R are in contact with the blue light-emitting element 200B, the green light-emitting element 200G, and the blue light-emitting element 200B, respectively. In the light-emitting device 10A, the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R in each pixel 130 are electrically connected to the control circuit in the circuit board 100 and are controlled by the control circuit.

[0068] Since the amorphous substrate 310 is the same as the amorphous substrate 110, its description is omitted here.

[0069] Although not shown in the diagram, the circuit board 100 and the amorphous substrate 310 are bonded and fixed together via an adhesive or sealant. The space between the circuit board 100 and the amorphous substrate 310 may be filled with air or a gas such as nitrogen, or it may be filled with an adhesive or the like. In addition, to maintain a constant distance between the circuit board 100 and the amorphous substrate 310, a spacer may be provided between the circuit board 100 and the amorphous substrate 310, or spacers may be scattered between them.

[0070] [2. Method for Manufacturing the Light-Emitting Device 10A] Next, the method for manufacturing the light-emitting device 10A will be described with reference to Figures 12 to 15.

[0071] Figure 12 is a flowchart illustrating a method for manufacturing a light-emitting device 10A according to one embodiment of the present invention. Figures 13 to 15 are schematic cross-sectional views illustrating a method for manufacturing a light-emitting device 10A according to one embodiment of the present invention.

[0072] As shown in Figure 12, the manufacturing method of the light-emitting device 10A broadly includes the steps of forming a control circuit on an amorphous substrate 110, forming a blue light-emitting element 200B in step S200, forming a green light-emitting element 200G in step S300, forming a red light-emitting element 200R in step S400, and bonding the circuit board 100 (amorphous substrate 110) to the amorphous substrate 310 in step S500. In the light-emitting device 10A, the blue light-emitting element 200B and the green light-emitting element 200G are formed on the circuit board 100 (steps S100, S200, and S300), while the red light-emitting element 200R is formed using an amorphous substrate 310 that is different from the amorphous substrate 110 of the circuit board 100 (step S400). Steps S100, S200, and S300 in this embodiment are the same as steps S100, S200, and S300 in the method for manufacturing the light-emitting device 10, so their explanation is omitted here. Steps S400 and S500 will be described below with reference to Figures 13 to 15 as appropriate.

[0073] Step S400 includes steps S410 and S420.

[0074] In step S410, a buffer layer 280R is formed on the amorphous substrate 310 (see Figure 13). The buffer layer 280R is deposited on the amorphous substrate 310 at a temperature of less than 650°C using sputtering or CVD, and is formed into a predetermined pattern shape using photolithography.

[0075] In step S420, a red light-emitting element 200R is formed on the buffer layer 280R. In step S420 of the manufacturing method of the light-emitting device 10A, the multiple red light-emitting elements 200R are formed so as not to collide with the blue light-emitting elements 200B and the green light-emitting elements 200G when the amorphous substrate 310 is bonded to the circuit board 100 in step S500, which will be described later. In other words, each of the multiple red light-emitting elements 200R is formed spaced apart so that it is positioned within the pixel 130 when the amorphous substrate 310 is bonded to the circuit board 100.

[0076] In step S500, the circuit board 100 on which the blue light-emitting element 200B and the green light-emitting element 200G are formed is bonded to the amorphous substrate 310 on which the red light-emitting element 200R is formed. Before bonding the circuit board 100 and the amorphous substrate 310, an adhesive or sealant is applied to at least one of the circuit board 100 or the amorphous substrate 310, and spacers are scattered. This allows the circuit board 100 and the amorphous substrate 310 to be bonded and fixed with a predetermined gap.

[0077] Although a detailed explanation will be omitted, in the manufacturing method of the light-emitting device 10A, before step S500, the blue light-emitting element 200B and the green light-emitting element 200G are electrically connected to the control circuit in the pixel 130, and in step S500, the red light-emitting element 200R is electrically connected to the control circuit in the pixel 130. As a result, the light-emitting device 10A shown in Figure 11 is manufactured.

[0078] The configuration and manufacturing method of the light-emitting device 10A have been described above. However, the light-emitting device 10A can also use a circuit board in which control circuits are formed on an amorphous substrate 310. For example, control circuits for controlling the blue light-emitting element 200B and the green light-emitting element 200G can be formed on the amorphous substrate 110, and a control circuit for controlling the red light-emitting element 200R can be formed on the amorphous substrate 310. In this case, since the light-emitting element 200 can be formed on the circuit board, electrical connection between the light-emitting element and the circuit board becomes easier. Also, since only the red light-emitting element 200R is formed on the amorphous substrate 310, a wide area where the red light-emitting element 200R is not provided can be secured. In this case, control circuits for controlling all of the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R can be formed in such a wide area on the amorphous substrate 310.

[0079] According to the light-emitting device 10A of this embodiment, a red light-emitting element 200R containing an arsenide semiconductor or phosphide semiconductor can be formed by adjusting the material of the buffer layer 280R formed on the amorphous substrate 310 bonded to the circuit board 100. Therefore, it can be manufactured at low cost using an amorphous substrate, and can have high luminescence efficiency not only for blue and green light emission, but also for red light emission.

[0080] <Third Embodiment> The light-emitting device 10 and the light-emitting device 10B, which is different from the light-emitting device 10A, will be described with reference to Figures 16 to 19. In the following, the description of configurations similar to those in the first or second embodiment may be omitted.

[0081] [1. Configuration of Light-Emitting Device 10B] Figure 16 is a schematic cross-sectional view showing the configuration of a light-emitting device 10A according to one embodiment of the present invention.

[0082] As shown in Figure 16, the light-emitting device 10B includes a circuit board 100, a blue light-emitting element 200B, a green light-emitting element 200G, a red light-emitting element 200R, and buffer layers 280B, 280G, and 280R. The light-emitting device 10B has a structure in which the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R are arranged on a circuit board 100 on which a control circuit is formed on an amorphous substrate 110. The blue light-emitting element 200B is provided on the circuit board 100 with the buffer layer 280B in between. The green light-emitting element 200G is provided on the circuit board 100 with the buffer layer 280G in between. The red light-emitting element 200R is provided between the buffer layer 280R and the circuit board 100. In other words, unlike the buffer layers 280B and 280G, the buffer layer 280R is provided on the opposite side of the circuit board 100 with the red light-emitting element 200R in between. The buffer layers 280B, 280G, and 280R are in contact with the blue light-emitting element 200B, the green light-emitting element 200G, and the blue light-emitting element 200B, respectively. In the light-emitting device 10B, the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R in each pixel 130 are electrically connected to the control circuit of the circuit board 100 and are controlled by the control circuit.

[0083] [2. Method for Manufacturing the Light-Emitting Device 10B] Next, the method for manufacturing the light-emitting device 10B will be described with reference to Figures 17 to 19.

[0084] Figure 17 is a flowchart illustrating a method for manufacturing a light-emitting device 10B according to one embodiment of the present invention. Figures 18 and 19 are schematic cross-sectional views illustrating a method for manufacturing a light-emitting device 10B according to one embodiment of the present invention.

[0085] As shown in Figure 17, the manufacturing method of the light-emitting device 10B broadly includes the steps of manufacturing a circuit board 100 (step S100), forming a blue light-emitting element 200B (step S200), forming a green light-emitting element 200G (step S300), forming a red light-emitting element 200R (step S400), and transferring the red light-emitting element 200R to the circuit board 100 (step S600). In the light-emitting device 10B, the blue light-emitting element 200B and the green light-emitting element 200G are formed on the circuit board 100 (steps S100, S200, and S300), while the red light-emitting element 200R is formed using an amorphous substrate 310 that is different from the amorphous substrate 110 of the circuit board 100 (step S400). Steps S100, S200, S300, and S400 in this embodiment are the same as those in the manufacturing method of the light-emitting device 10A, so their explanation is omitted here. Step S600 will be described below with reference to Figures 18 and 19 as appropriate.

[0086] Step S600 includes steps S610, S620, and S630.

[0087] In step S610, the amorphous substrate 310 is placed on the circuit board 100, and the circuit board 100 and the amorphous substrate 310 are bonded together. Unlike step S500, in step S610, the circuit board 100 and the amorphous substrate 310 are not fixed together with adhesive or sealant. However, it is preferable that the red light-emitting element 200R on the amorphous substrate 310 is bonded or adhered to the circuit board 100. For example, the red light-emitting element 200R may be bonded to the circuit board 100 via a conductive adhesive such that the p-type electrode 250 and the n-type electrode 260 are electrically connected to the control circuit of the circuit board 100, respectively.

[0088] In step S620, the buffer layer 280R is irradiated with a laser (see Figure 18). The laser has a wavelength that is absorbed by the buffer layer 280R. This separates the buffer layer 280R from the amorphous substrate 310. Conventional buffer layers contain materials with a large band gap, so short-wavelength lasers such as excimer lasers are used to irradiate the buffer layer 280R. In contrast, the buffer layer 280R contains a metal or a semiconductor or insulator with a small band gap. Therefore, long-wavelength lasers such as visible light lasers or infrared lasers are used to irradiate the buffer layer 280R. For example, the wavelength of the laser irradiated onto the buffer layer 280R is 300 nm to 2,200 nm, preferably 300 nm to 1,100 nm, and more preferably 600 nm to 1,100 nm.

[0089] In step S630, the amorphous substrate 310 is removed (see Figure 19). Since the red light-emitting element 200R is separated from the amorphous substrate 310 together with the buffer layer 280R, the red light-emitting element 200R is transferred from the amorphous substrate 310 to the circuit board 100. As shown in Figure 19, unlike the blue light-emitting element 200B and the green light-emitting element 200G, the red light-emitting element 200R is located between the circuit board 100 and the buffer layer 280R. This results in the production of the light-emitting device 10B shown in Figure 16.

[0090] In the manufacturing method of the light-emitting device 10B, the size of the amorphous substrate 310 is not particularly limited. For example, the amorphous substrate 310 may be smaller than the amorphous substrate 110. In this case, by repeatedly performing step S600 for one circuit board 100, multiple red light-emitting elements 200R can be transferred to the circuit board 100.

[0091] According to the light-emitting device 10B of this embodiment, a red light-emitting element 200R containing an arsenide semiconductor or phosphide semiconductor can be formed by adjusting the material of the buffer layer 280R formed on an amorphous substrate 310 that is different from the amorphous substrate 110 of the circuit board 100. Furthermore, the red light-emitting element 200R formed on the amorphous substrate 310 is transferred to the circuit board 100 using a laser with lower energy than conventional methods, utilizing the buffer layer 280R. Therefore, it is possible to manufacture the device at low cost using an amorphous substrate, and it is possible to have high luminescence efficiency not only for blue and green light emission, but also for red light emission.

[0092] <Modification of the Third Embodiment> Referring to Figure 20, a modification of the light-emitting device 10B, the light-emitting device 10C, will be described.

[0093] Figure 20 is a schematic cross-sectional view showing the configuration of a light-emitting device 10C according to one embodiment of the present invention.

[0094] As shown in Figure 20, the light-emitting device 10C includes a circuit board 100, a blue light-emitting element 200B, a green light-emitting element 200G, a red light-emitting element 200R, and buffer layers 280B and 280G. Unlike the light-emitting device 10B, the light-emitting device 10C does not include the buffer layer 280R. In the light-emitting device 10C, after the red light-emitting element 200R is transferred to the circuit board 100, the buffer layer 280, which was transferred to the circuit board 100 together with the red light-emitting element 200R, is removed by etching. If a different material is used for the buffer layer 280R than for buffer layers 280B and 280G, only the buffer layer 280R can be selectively etched.

[0095] Furthermore, when etching the buffer layer 280R, a protective layer (for example, silicon nitride) may be provided to cover the back surface of the circuit board 100 (the surface opposite to the surface on which the control circuit is formed). By covering the amorphous substrate 110 of the circuit board 100 with a protective layer, etching of the amorphous substrate 110 can be prevented.

[0096] Since the light-emitting device 10C according to this modified example does not include a buffer layer 280R, the light emitted from the red light-emitting element 200R on the circuit board 100 is not affected by the buffer layer 280R. Therefore, the light extraction efficiency of the red light-emitting element 200R is improved in the light-emitting device 10C.

[0097] <Fourth Embodiment> A light-emitting device 10D, which is different from light-emitting devices 10 to 10C, will be described with reference to Figures 21 to 25. In the following, the description of configurations similar to those in the first to third embodiments may be omitted.

[0098] [1. Configuration of the light-emitting device 10D] Figure 21 is a schematic cross-sectional view showing the configuration of the light-emitting device 10D according to one embodiment of the present invention.

[0099] As shown in Figure 21, the light-emitting device 10D includes a circuit board 100, a blue light-emitting element 200B, a green light-emitting element 200G, a red light-emitting element 200R, and buffer layers 280B, 280G, and 280R. The blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R are provided on the circuit board 100. The buffer layer 280B is provided on the blue light-emitting element 200B. In other words, the buffer layer 280B is provided on the opposite side of the circuit board 100 with the blue light-emitting element 200B in between. The buffer layer 280G is provided on the green light-emitting element 200G. In other words, the buffer layer 280G is provided on the opposite side of the circuit board 100 with the green light-emitting element 200G in between. The buffer layer 280R is provided on the red light-emitting element 200R. In other words, the buffer layer 280R is located on the opposite side of the circuit board 100, with the red light-emitting element 200R in between. The buffer layers 280B, 280G, and 280R are in contact with the blue light-emitting element 200B, the green light-emitting element 200G, and the blue light-emitting element 200B, respectively. In the light-emitting device 10D, the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R in each pixel 130 are electrically connected to the control circuit of the circuit board 100 and are controlled by the control circuit.

[0100] [2. Method for Manufacturing the Light-Emitting Device 10D] Next, the method for manufacturing the light-emitting device 10D will be described with reference to Figures 22 to 25.

[0101] Figure 22 is a flowchart illustrating a method for manufacturing a light-emitting device 10D according to one embodiment of the present invention. Figures 23 to 25 are schematic cross-sectional views illustrating a method for manufacturing a light-emitting device 10D according to one embodiment of the present invention.

[0102] As shown in Figure 22, the manufacturing method of the light-emitting device 10D is broadly divided into the steps of: manufacturing a circuit board 100 (step S100); forming a blue light-emitting element 200B (step S200); forming a green light-emitting element 200G (step S300); forming a red light-emitting element 200R (step S400); transferring the blue light-emitting element 200B to the circuit board 100 (step S600B); transferring the green light-emitting element 200G to the circuit board 100 (step S600G); and transferring the red light-emitting element 200R to the circuit board 100 (step S600R). In the light-emitting device 10D, the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R are formed using amorphous substrates 310B, 310G, and 310R, respectively (steps S200, S300, and S400). Step S100 in this embodiment is the same as step S100 in the method for manufacturing the light-emitting device 10, so its explanation is omitted here. Steps S200, S300, and S400 in this embodiment are the same as step S400 in the method for manufacturing the light-emitting device 10A, so their explanation is omitted here. Steps S600B, S600G, and S600R will be described below with reference to Figures 23 to 25 as appropriate.

[0103] In step S600B, the blue light-emitting element 200B formed on the amorphous substrate 310B is transferred onto the circuit board 100 using a laser, and then the amorphous substrate 310B is removed (see Figure 23).

[0104] In step S600G, the green light-emitting element 200G formed on the amorphous substrate 310G is transferred onto the circuit board 100 using a laser, and then the amorphous substrate 310G is removed (see Figure 24).

[0105] In step S600G, the red light-emitting element 200R formed on the amorphous substrate 310R is transferred onto the circuit board 100 using a laser, and then the amorphous substrate 310R is removed (see Figure 25). This manufactures the light-emitting device 10D shown in Figure 21.

[0106] Steps S600B, S600G, and S600R have been described above, but steps S600B, S600G, and S600R may be performed in this order, or the order of steps S600B, S600G, and S600R may be changed.

[0107] According to the light-emitting device 10D of this embodiment, a blue light-emitting element 200B containing a nitride semiconductor can be formed by adjusting the material of the buffer layer 280B formed on the amorphous substrate 310B, a green light-emitting element 200G containing a nitride semiconductor can be formed by adjusting the material of the buffer layer 280G formed on the amorphous substrate 310G, and a red light-emitting element 200R containing an arsenide semiconductor or phosphide semiconductor can be formed by adjusting the material of the buffer layer 280R formed on the amorphous substrate 310R. Furthermore, the blue light-emitting element 200B, green light-emitting element 200G, and red light-emitting element 200R formed on the amorphous substrates 310B, 310G, and 310R, respectively, are transferred to the circuit board 100 using a laser with lower energy than conventional methods, utilizing the buffer layers 280B, 280G, and 280R. Therefore, it is possible to manufacture the device at low cost using an amorphous substrate, and it is possible to have high luminescence efficiency not only for blue and green light emission, but also for red light emission.

[0108] <Modification 1 of the Fourth Embodiment> Referring to Figure 26, a modified light-emitting device 10E, which is a modified version of the light-emitting device 10D, will be described.

[0109] Figure 26 is a schematic cross-sectional view showing the configuration of a light-emitting device 10E according to one embodiment of the present invention.

[0110] As shown in Figure 26, the light-emitting device 10E includes a circuit board 100, a blue light-emitting element 200B, a green light-emitting element 200G, and a red light-emitting element 200R. Unlike the light-emitting device 10D, the light-emitting device 10E does not include buffer layers 280B, 280G, and 280R. In the light-emitting device 10E, after the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R are transferred to the circuit board 100, the buffer layers 280B, 280G, and 280R are removed by etching.

[0111] Since the light-emitting device 10E according to this modified example does not include buffer layers 280B, 280G, and 280R, the light emitted from the blue light-emitting element 200B, green light-emitting element 200G, and red light-emitting element 200R on the circuit board 100 is not affected by the buffer layers 280B, 280G, and 280R. Therefore, the light extraction efficiency of the blue light-emitting element 200B, green light-emitting element 200G, and red light-emitting element 200R is improved in the light-emitting device 10E.

[0112] <Modification 2 of the 4th Embodiment> Referring to Figures 27 to 32, another modification of the light-emitting device 10D, the light-emitting device 10F, will be described.

[0113] [1. Configuration of the light-emitting device 10F] Figure 27 is a schematic cross-sectional view showing the configuration of the light-emitting device 10F according to one embodiment of the present invention.

[0114] As shown in Figure 27, the light-emitting device 10F includes a circuit board 100, a blue light-emitting element 200B, a green light-emitting element 200G, a red light-emitting element 200R, and buffer layers 280B, 280G, and 280R. The blue light-emitting element 200B is provided on the circuit board 100 with the buffer layer 280B in between. The green light-emitting element 200G is provided on the circuit board 100 with the buffer layer 280G in between. The red light-emitting element 200R is also provided on the circuit board 100 with the buffer layer 280R in between. The buffer layers 280B, 280G, and 280R are in contact with the blue light-emitting element 200B, the green light-emitting element 200G, and the blue light-emitting element 200B, respectively. In the light-emitting device 10F, the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R in each pixel 130 are electrically connected to the control circuit of the circuit board 100 and are controlled by the control circuit.

[0115] [2. Method for Manufacturing the Light-Emitting Device 10F] Next, the method for manufacturing the light-emitting device 10F will be described with reference to Figures 28 to 33.

[0116] Figure 28 is a flowchart illustrating the manufacturing method of the light-emitting device 10F according to one embodiment of the present invention. Figures 29 to 33 are schematic cross-sectional views illustrating the manufacturing method of the light-emitting device 10F according to one embodiment of the present invention.

[0117] In the manufacturing method of the light-emitting device 10F, similar to the light-emitting device 10D, a circuit board 100 is manufactured (step S100 in Figure 22), a blue light-emitting element 200B is formed on an amorphous substrate 310B (step S200 in Figure 22), a green light-emitting element 200G is formed on an amorphous substrate 310G (step S300 in Figure 22), and a red light-emitting element 200R is formed on an amorphous substrate 310R (step S400 in Figure 22). On the other hand, in the manufacturing method of the light-emitting device 10F, the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R are transferred to the circuit board 100 using a carrier substrate 400. Figure 28 shows step S600A in which the red light-emitting element 200R is transferred to the circuit board 100, but the blue light-emitting element 200B and the green light-emitting element 200G can also be transferred to the circuit board 100 using the same method as in step S600A. Step S600A will now be explained with reference to Figures 29 to 33 as appropriate.

[0118] Step S600A includes steps S610A to S650A.

[0119] In step S610A, a carrier substrate 400 is placed on the amorphous substrate 310R, and the amorphous substrate 310 and the carrier substrate 400 are bonded together (see Figure 29). The carrier substrate 400 is a substrate for transferring a light-emitting element 200 that is different from the circuit board 100. The carrier substrate 400 is in contact with the light-emitting element 200, allowing the light-emitting element 200 to be adhered to it. For example, the carrier substrate 400 includes an elastic body to which the light-emitting element 200 can be adhered. For example, as the elastic body, natural rubber (NR), silicone rubber (SI), polyurethane rubber (PUR), fluororubber (FPM), nitrile rubber (NBR), styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), ethylene propylene diene rubber (EPDM), acrylic rubber (ACM), isobutylene-isoprene rubber (IIR), or materials made by combining these rubbers individually or in mixtures can be used. In particular, when high heat resistance is required, it is preferable to use silicone rubber or fluororubber as the elastic material.

[0120] In step S620A, the buffer layer 280R is irradiated with a laser (see Figure 30). This separates the buffer layer 280R from the amorphous substrate 310R.

[0121] In step S630A, the amorphous substrate 310R is removed. As a result, the red light-emitting element 200R formed on the laser-irradiated buffer layer 280R is picked up by the carrier substrate 400.

[0122] In step S640A, a carrier substrate with the red light-emitting element 200R picked up is placed on the circuit board 100, and the circuit board 100 and the carrier substrate 400 are bonded together (see Figure 32). As a result, the buffer layer 280R on the carrier substrate 400 comes into contact with the circuit board 100, and it is preferable that the buffer layer 280R is bonded or adhered to the circuit board 100. Furthermore, it is preferable that the bonding or adhesive force between the buffer layer 280R and the circuit board 100 is greater than the adhesive force between the buffer layer 280R and the carrier substrate 400.

[0123] In step S650A, the red light-emitting element 200R is released from the carrier substrate 400 (see Figure 33). This separates the red light-emitting element 200R from the carrier substrate 400, and it is transferred to the circuit board 100. Although a detailed explanation is omitted, after step S650A, if necessary, a step may be included in which the blue light-emitting element 200B, the green light-emitting element 200G, and the red light-emitting element 200R are electrically connected to the control circuit in the pixel 130 (a step of forming wiring). This manufactures the light-emitting device 10F shown in Figure 27.

[0124] The light-emitting device 10F according to this modified example can not only transfer multiple red light-emitting elements 200R (multiple blue light-emitting elements 200B or multiple green light-emitting elements 200G) onto the circuit board 100 at once via the carrier substrate 400, but can also selectively transfer red light-emitting elements 200R by adjusting the position where the laser is irradiated.

[0125] The embodiments described above as embodiments of the present invention can be combined and implemented as appropriate, insofar as they do not contradict each other. Furthermore, any additions, deletions, or design changes to components, or additions, omissions, or changes to processes based on these embodiments, made by those skilled in the art, are also included within the scope of the present invention, as long as they retain the essence of the present invention.

[0126] 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.

[0127] 10, 10A, 10B, 10C, 10D, 10E, 10F: Light-emitting device, 100: Circuit board, 110: Amorphous substrate, 110a: Display unit, 110b: Drive circuit unit, 110c: Terminal unit, 120: Terminal, 130: Pixel, 200: Light-emitting element, 200B: Blue light-emitting element, 200G: Green light-emitting element, 200R: Red light-emitting element, 220: n-type semiconductor layer, 230: Light-emitting layer, 240: p-type semiconductor layer, 250: p-type electrode, 260: n-type electrode, 280B, 280G, 280R: Buffer layer, 310, 310B, 310G, 310R: Amorphous substrate, 400: Carrier substrate, Cap: Capacitive element, GL: Scan line, PVH: Power line, PVL: Reference power line, SL: Signal line, Tr1: First transistor, Tr2: Second transistor

Claims

1. A light-emitting device comprising a first amorphous substrate and a red light-emitting element including a red light-emitting layer on the first amorphous substrate, wherein the red light-emitting layer comprises at least one of an arsenide semiconductor and a phosphide semiconductor, and the red light-emitting layer is formed by sputtering.

2. The light-emitting apparatus according to claim 1, further comprising a first buffer layer in contact with the red light-emitting element, wherein the first buffer layer comprises at least one of germanium, silicon, and graphene.

3. The light-emitting device according to claim 2, wherein the first buffer layer is provided on the side opposite to the first amorphous substrate, with the red light-emitting element in between.

4. The light-emitting device according to claim 1, further comprising: a blue light-emitting element having a blue light-emitting layer on the first amorphous substrate; and a green light-emitting element having a green light-emitting layer on the first amorphous substrate, wherein each of the blue light-emitting layer and the green light-emitting layer comprises a nitride semiconductor, and each of the blue light-emitting layer and the green light-emitting layer is formed by sputtering.

5. The light-emitting device according to claim 4, further comprising: a first buffer layer in contact with the red light-emitting element; a second buffer layer in contact with the blue light-emitting element; and a third buffer layer in contact with the green light-emitting element, wherein the first buffer layer comprises a material different from that of the second buffer layer and the third buffer layer.

6. The light-emitting apparatus according to claim 5, wherein the first buffer layer comprises at least one of germanium, silicon, and graphene.

7. The light-emitting apparatus according to claim 6, wherein each of the second buffer layer and the third buffer layer comprises at least one of titanium, silicon, zinc oxide, and zirconium.

8. The light-emitting device according to claim 5, wherein the first buffer layer is provided between the first amorphous substrate and the red light-emitting element, the second buffer layer is provided between the first amorphous substrate and the blue light-emitting element, and the third buffer layer is provided between the first amorphous substrate and the green light-emitting element.

9. The light-emitting device according to claim 5, wherein the first buffer layer is provided on the opposite side of the first amorphous substrate with the red light-emitting element in between, the second buffer layer is provided on the opposite side of the first amorphous substrate with the blue light-emitting element in between, and the third buffer layer is provided on the opposite side of the first amorphous substrate with the green light-emitting element in between.

10. The light-emitting device according to claim 5, wherein the first buffer layer is provided on the opposite side of the first amorphous substrate with the red light-emitting element in between, the second buffer layer is provided between the first amorphous substrate and the blue light-emitting element, and the third buffer layer is provided between the first amorphous substrate and the green light-emitting element.

11. The light-emitting device according to claim 10, further comprising a second amorphous substrate facing the first amorphous substrate, with the blue light-emitting element, the green light-emitting element, and the red light-emitting element sandwiched between them.

12. A method for manufacturing a light-emitting device, comprising: forming a first buffer layer on a first amorphous substrate; forming a red light-emitting element including a red light-emitting layer on the first buffer layer, wherein the red light-emitting layer is formed by sputtering; and the red light-emitting layer includes at least one of an arsenide semiconductor and a phosphide semiconductor.

13. The method for manufacturing a light-emitting device according to claim 12, further comprising forming a second buffer layer and a third buffer layer on the first amorphous substrate, and forming a blue light-emitting element including a blue light-emitting layer and a green light-emitting element including a green light-emitting layer on the second buffer layer and the third buffer layer, respectively, wherein each of the blue light-emitting layer and the green light-emitting layer is deposited by sputtering, the first buffer layer comprises a different material from the second buffer layer and the third buffer layer, and each of the blue light-emitting layer and the green light-emitting layer comprises a nitride semiconductor.

14. The method for manufacturing a light-emitting device according to claim 12, further comprising: forming a second buffer layer and a third buffer layer on a second amorphous substrate; forming a blue light-emitting element including a blue light-emitting layer and a green light-emitting element including a green light-emitting layer on the second buffer layer and the third buffer layer, respectively; bonding the first amorphous substrate and the second amorphous substrate with the blue light-emitting element, the green light-emitting element, and the red light-emitting element sandwiched between them; each of the blue light-emitting layer and the green light-emitting layer being formed by sputtering; and each of the blue light-emitting layer and the green light-emitting layer containing a nitride semiconductor.

15. The method for manufacturing a light-emitting device according to claim 12, further comprising: forming a second buffer layer and a third buffer layer on a second amorphous substrate; forming a blue light-emitting element including a blue light-emitting layer and a green light-emitting element including a green light-emitting layer on the second buffer layer and the third buffer layer, respectively; and transferring the red light-emitting element from the first amorphous substrate to the second amorphous substrate, wherein each of the blue light-emitting layer and the green light-emitting layer is formed by sputtering; and each of the blue light-emitting layer and the green light-emitting layer includes a nitride semiconductor.

16. The method for manufacturing a light-emitting device according to claim 15, wherein the red light-emitting element is transferred to the second amorphous substrate by irradiating the first buffer layer with a laser.

17. The method for manufacturing a light-emitting device according to claim 16, further comprising removing the first buffer layer which is transferred to the first amorphous substrate together with the red light-emitting element.

18. The method for manufacturing a light-emitting device according to claim 15, wherein the red light-emitting element is transferred from the first amorphous substrate to the second amorphous substrate via a carrier substrate.

19. The method for manufacturing a light-emitting device according to claim 12, further comprising: forming a second buffer layer on a second amorphous substrate; forming a blue light-emitting element including a blue light-emitting layer on the second buffer layer; forming a third buffer layer on a third amorphous substrate; forming a green light-emitting element including a green light-emitting layer on the third buffer layer; transferring the red light-emitting element from the first amorphous substrate to a fourth amorphous substrate; transferring the blue light-emitting element from the second amorphous substrate to the fourth amorphous substrate; and transferring the green light-emitting element from the third amorphous substrate to the fourth amorphous substrate, wherein each of the blue light-emitting layer and the green light-emitting layer is formed by sputtering; and each of the blue light-emitting layer and the green light-emitting layer contains a nitride semiconductor.

20. The method for manufacturing a light-emitting device according to any one of claims 12 to 19, wherein the first buffer layer comprises at least one of germanium, silicon, and graphene.

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