Epitaxial structure of gallium nitride-based diode and preparation method thereof

Abstract

The invention discloses an epitaxial structure of a gallium nitride-based diode and a preparation method of the epitaxial structure, and belongs to the technical field of semiconductors, and the epitaxial structure comprises a first electrode, a first ITO layer, a p-type GaN layer, a multi-quantum well, an n-type GaN layer, a second ITO layer, a total reflection layer, a second electrode and a conductive support which are sequentially laminated, and the first electrode, the first ITO layer, the p-type GaN layer, the multi-quantum well, the n-type GaN layer, the second ITO layer, the total reflection layer and the conductive support are sequentially laminated. The multi-quantum well comprises an InGaN quantum well layer and a GaN barrier layer which are periodically arranged in a laminated mode, an ohmic contact array is arranged on the total reflection layer in a penetrating mode, and the spacing distances between adjacent conductor media in the ohmic contact array are consistent; the second ITO is connected with the second electrode through the conductor medium, and under the condition that the first electrode and the second electrode are connected, electrons and holes generated by the p-type GaN layer and the n-type GaN layer emit light in the multi-quantum well in a composite mode. The light extraction efficiency of the diode is effectively improved.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology, and particularly relates to an epitaxial structure of a gallium nitride-based diode and a preparation method thereof. Background Art

[0002] A gallium nitride-based diode is a semiconductor diode made of gallium nitride material. Gallium nitride material has excellent properties such as a wide bandgap, high thermal conductivity, and high breakdown voltage, so it is widely used in diodes and other semiconductor devices for high-power, high-frequency, and high-temperature working environments. The epitaxial structure refers to the process of growing different semiconductor materials layer by layer on a substrate material through an epitaxial growth method to form a multi-layer structure. The materials between these layers have different electrical and optical properties, and the thickness, doping concentration, etc. of each layer play an important role in the performance of the final device.

[0003] The epitaxial structure of a gallium nitride-based diode is the core of its performance. Different structures and material combinations of the epitaxial layer determine the electronic characteristics, photoelectric conversion efficiency, and thermal stability of the diode. Optimization of the epitaxial structure can improve the conductivity of the device, reduce energy loss, and improve the light extraction efficiency, ensuring the stable operation of the diode in high-power and high-temperature environments. Therefore, the design and optimization of the epitaxial structure play a crucial role in improving the performance and application of gallium nitride-based diodes.

[0004] However, the existing epitaxial structures of gallium nitride-based diodes usually do not consider a large amount of light loss inside the device. Due to different epitaxial structures, the expected light extraction efficiency cannot be achieved. Moreover, the active region, i.e., the quantum well region, usually adopted does not consider the tunneling effect of carriers, which reduces the carrier recombination efficiency, further reduces the light extraction efficiency of the diode, increases the energy loss of the device, and affects the quality and working efficiency of the diode. Summary of the Invention

[0005] In order to solve the technical problems in the prior art that the epitaxial structures of gallium nitride-based diodes usually do not consider a large amount of light loss inside the device, the expected light extraction efficiency cannot be achieved due to different epitaxial structures, and the active region, i.e., the quantum well region, usually adopted does not consider the tunneling effect of carriers, which reduces the carrier recombination efficiency, further reduces the light extraction efficiency of the diode, increases the energy loss of the device, and affects the quality and working efficiency of the diode, the present invention provides an epitaxial structure of a gallium nitride-based diode and a preparation method thereof.

[0006] In the first aspect, the present invention provides an epitaxial structure of a gallium nitride-based diode, including: a first electrode, a first ITO layer, a p-type GaN layer, a multi-quantum well, an n-type GaN layer, a second ITO layer, a total reflection layer, a second electrode, and a conductive support; The first electrode, the first ITO layer, the p-type GaN layer, the multiple quantum wells, the n-type GaN layer, the second ITO layer, the total reflection layer, the second electrode, and the conductive bracket are stacked in sequence; The multiple quantum wells include periodically stacked InGaN quantum well layers and GaN barrier layers. Among them, the GaN barrier layers are used to confine electrons and holes in the InGaN quantum well layers; An ohmic contact array is provided on the total reflection layer in a penetrating manner. Among them, the spacing distances between adjacent conductor media in the ohmic contact array are the same; The second ITO is connected to the second electrode through a conductor medium. When the first electrode and the second electrode are connected, the electrons and holes generated by the p-type GaN layer and the n-type GaN layer recombine and emit light in the multiple quantum wells.

[0007] In a second aspect, the present invention provides a method for preparing an epitaxial structure of a gallium nitride-based diode. The method includes: S1: Grow a total reflection layer, a second ITO layer, an n-type GaN layer, multiple quantum wells, a p-type GaN layer, and a first ITO layer on a substrate in sequence; S2: Generate an ohmic contact array on the total reflection layer through a photolithography technique; S3: Remove the substrate; S4: Generate a first electrode and a second electrode; S5: Bond a conductive bracket to the second electrode to obtain an epitaxial structure of a gallium nitride-based diode.

[0008] Compared with the prior art, the present invention has at least the following beneficial technical effects: By providing two ITO layers, the present invention improves the light extraction efficiency. Moreover, a total reflection layer is provided on one side of the second ITO layer to reflect the light originally absorbed by other layers to the second ITO layer for repeated extraction, further reducing light loss and improving the light extraction efficiency. In addition, an ohmic contact array is provided on the total reflection layer in a penetrating manner. Among them, the spacing distances between adjacent conductor media in the ohmic contact array are the same. The uniform spacing of the ohmic contact array may ensure a more uniform current distribution, reduce local hot spots, and avoid excessive metal blocking of light, thereby ensuring a balanced current input without affecting light reflection. The multiple quantum well region is a periodically stacked structure of InGaN quantum well layers and GaN barrier layers. The setting of the barrier layers can suppress the tunneling effect of carriers, confine more carriers in the InGaN quantum well layers to improve the carrier recombination efficiency, enhance the light emission efficiency of the diode, improve the light extraction efficiency of the diode under the condition of constant voltage, reduce the energy loss of the device, and improve the device quality. Description of the Drawings

[0009] The above characteristics, technical features, advantages and their implementation manners of the present invention will be further described below in a clear and understandable manner in conjunction with the accompanying drawings.

[0010] Figure 1 It is a schematic structural diagram of an epitaxial structure of a gallium nitride-based diode provided by the present invention; Figure 2 It is a schematic flow diagram of a preparation method of an epitaxial structure of a gallium nitride-based diode provided by the present invention. Specific Embodiments

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific embodiments of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings and other embodiments can be obtained.

[0012] Embodiment 1 In one embodiment, referring to the accompanying drawings of the specification Figure 1 It shows a schematic structural diagram of an epitaxial structure of a gallium nitride-based diode provided by the present invention.

[0013] Figure 1 The epitaxial structure of the gallium nitride-based diode is shown, from top to bottom in sequence: a first electrode, a first ITO layer, a p-type GaN layer, a multi-quantum well layer (InGaN quantum well and GaN barrier layer), an n-type GaN layer, a second ITO layer, a total reflection layer, a second electrode, and a conductive bracket. Through this multi-layer structure design, the light extraction efficiency is improved. In particular, by setting two ITO layers and a total reflection layer to reduce light loss and reflecting the unemitted light back to the multi-quantum well region for repeated extraction, thereby enhancing the overall light emission efficiency of the LED. In addition, the uniform distribution of the ohmic contact array helps to ensure the uniform distribution of current, reduce local hot spots and avoid excessive metal blocking light. The InGaN quantum well and GaN barrier layer in the multi-quantum well layer can effectively confine carriers, improve the carrier recombination efficiency, and thus improve the light emission and extraction efficiency. Through these optimizations, the diode improves the light extraction efficiency while maintaining the voltage constant, reduces energy loss, and ultimately enhances the quality and performance of the device.

[0014] An epitaxial structure of a gallium nitride-based diode provided by the present invention includes: a first electrode, a first ITO layer, a p-type GaN layer, a multi-quantum well, an n-type GaN layer, a second ITO layer, a total reflection layer, a second electrode, and a conductive bracket.

[0015] Among them, the first electrode is a metal electrode in contact with the p-type GaN layer, responsible for injecting current into the p-type material of the diode. It provides a current source for the entire diode. The first ITO layer is a transparent conductive oxide layer (Indium Tin Oxide, ITO). It allows light to pass through and provides conductivity for injecting current into the p-type GaN layer, while allowing light to be emitted from the top of the diode. The p-type GaN layer is the p-type material layer of the gallium nitride-based diode, which is responsible for hole injection. This layer provides holes so that electrons and holes can recombine in the multiple quantum wells, thus emitting light. The multiple quantum wells are composed of periodically stacked InGaN quantum well layers and GaN barrier layers. The InGaN quantum well layers are used to improve the carrier recombination efficiency, while the GaN barrier layers confine the carriers within the quantum wells, reducing the carrier tunneling effect, thereby enhancing the light emission efficiency. The n-type GaN layer is the n-type material layer of the gallium nitride-based diode, responsible for providing electrons. Electrons enter the active region from the n-type GaN layer through the electrode and recombine with holes in the multiple quantum wells to emit light. The second ITO layer is another transparent conductive oxide material located above the n-type GaN layer. It provides a current conduction path to transfer current to the n-type GaN layer and allows light to pass through for emission from the LED chip. The total reflection layer (usually made of a high refractive index material) is located under the second ITO layer and is used to reflect the light emitted from inside the LED back into the diode, thereby reducing light loss. Through multiple reflections, the light output is enhanced. The second electrode is usually in contact with the n-type GaN layer and is responsible for injecting current into the n-type GaN layer, thereby providing electrons. The function of this layer is to ensure that current passes through the n-type GaN layer and finally flows into the multiple quantum well region. The conductive bracket is the part that supports the entire diode structure. It is usually a conductive metal bracket, ensuring the stability of the LED structure and providing a current introduction path. It helps to improve the heat dissipation of the diode and strengthen the physical support of the device.

[0016] It can be understood that through the precise design of different layers (including ITO layers, multiple quantum wells, total reflection layers, etc.) in this gallium nitride-based diode epitaxial structure, not only the current distribution is optimized, but also the light extraction efficiency is improved. The multiple quantum well layer improves the carrier recombination efficiency, and the total reflection layer improves the light output. The overall design enables the diode to have higher light emission efficiency and lower energy loss.

[0017] The first electrode, the first ITO layer, the p-type GaN layer, the multiple quantum wells, the n-type GaN layer, the second ITO layer, the total reflection layer, the second electrode, and the conductive bracket are stacked in sequence.

[0018] The multiple quantum wells include periodically stacked InGaN quantum well layers and GaN barrier layers, where the GaN barrier layers are used to confine electrons and holes in the InGaN quantum well layers.

[0019] It should be noted that the multiple quantum well structure is composed of periodically stacked InGaN quantum well layers and GaN barrier layers. The InGaN quantum well layer is the core region for carrier recombination, while the role of the GaN barrier layer is to confine electrons and holes within the quantum well, prevent them from escaping, and ensure that more carriers recombine in the quantum well, thereby improving the light emission efficiency.

[0020] An ohmic contact array is disposed on the total reflection layer in a penetrating manner, wherein the spacing between adjacent conductor media in the ohmic contact array is consistent.

[0021] It should be noted that the ohmic contact array on the total reflection layer is disposed in a penetrating manner to ensure that current can be evenly distributed to each region of the diode. The consistent spacing between adjacent conductor media in the array helps to evenly inject current, reduce local hot spots, and avoid excessive light blocking by the metal layer, thereby improving the light extraction efficiency and ensuring the balanced distribution of current.

[0022] The second ITO is connected to the second electrode through a conductor medium. When the first electrode and the second electrode are connected, electrons and holes generated by the p-type GaN layer and the n-type GaN layer recombine and emit light in the multiple quantum well.

[0023] In the actual application process, the epitaxial structure of the gallium nitride-based diode adopts a multi-layer design, including a first electrode, a first ITO layer, a p-type GaN layer, a multiple quantum well, an n-type GaN layer, a second ITO layer, a total reflection layer, a second electrode, and a conductive support. Among them, the first electrode provides a current source for the p-type GaN layer, the first ITO layer allows light to pass through and injects current, the p-type GaN layer provides holes, and recombines with electrons in the InGaN quantum well and GaN barrier layer in the multiple quantum well layer to emit light. The n-type GaN layer is responsible for providing electrons, and the second ITO layer conducts current and allows light emission. The total reflection layer improves the light extraction efficiency by reflecting the light that has not emitted from the multiple quantum well. At the same time, the ohmic contact array ensures the uniform distribution of current, reduces local hot spots, and avoids light loss. The second electrode ensures the inflow of electrons into the n-type GaN layer, ultimately improving the light emission efficiency. The entire structure optimizes the current distribution and light extraction efficiency, reduces energy loss, and improves the light emission performance of the diode.

[0024] In a possible implementation manner, the p-type GaN layer is a p-type GaN layer doped with Mg, and the thickness of the p-type GaN layer is 120 nm. The n-type GaN layer is an n-type GaN layer doped with Si, and the thickness of the n-type GaN layer is 2 μm.

[0025] It should be noted that the p-type GaN layer is doped with Mg to provide holes, making it a p-type material, and its thickness is 120 nm to ensure sufficient carrier injection. The n-type GaN layer is doped with Si to provide electrons, forming an n-type material, and its thickness is 2 μm to ensure good electron injection ability and optimize device performance. This doping method and thickness design help improve the current transmission efficiency and light emission efficiency of the diode.

[0026] In a possible implementation, the thicknesses of both the first ITO layer and the second ITO layer are 140 nm.

[0027] It should be noted that the thicknesses of both the first ITO layer and the second ITO layer are 140 nm. This thickness is selected to ensure that while providing sufficient conductivity, these two layers can still maintain good light transmittance. ITO materials have excellent transparency and conductivity, which enables them to fully meet the requirements of current injection without hindering light emission. This thickness design optimizes the light extraction efficiency while ensuring uniform current distribution.

[0028] In a possible implementation, with the target emission wavelength of the diode as a constraint, the thickness of the InGaN quantum well layer is determined by combining the Schrödinger equation. The specific calculation formula for the thickness of the InGaN quantum well layer is as follows: ; where, represents the thickness of the InGaN quantum well layer, represents the reduced Planck constant, π represents the pi, represents the effective mass of the carrier, represents the energy difference of the quantization level n related to InGaN, h represents the Planck constant, c represents the speed of light, represents the target emission wavelength, represents the bandgap of InGaN.

[0029] Among them, the Schrödinger equation is a fundamental equation in quantum mechanics, which describes the behavior and state of particles (such as electrons, photons, etc.) in a quantum system. The Schrödinger equation is one of the core equations of quantum mechanics and is used to predict and explain the wave properties of microscopic particles. Specifically, by combining the Schrödinger equation with the target emission wavelength, the design of the quantum well layer is ensured to achieve light emission at a specific wavelength. The Schrödinger equation takes into account multiple physical parameters, such as the effective mass of carriers, the energy difference of quantized energy levels, the target emission wavelength, and the bandgap of InGaN. Through the combination of these parameters, the thickness of the quantum well layer can be precisely controlled to optimize the generation and recombination efficiency of light. The advantage of this method is that the thickness of the quantum well layer can be customized according to specific optical requirements, ensuring that the light-emitting diode (LED) has a high light-emitting efficiency and making the working wavelength of the diode consistent with the design requirements, avoiding unnecessary energy loss, thereby improving the overall performance and light extraction efficiency.

[0030] In a possible implementation, with the constraint that the carrier tunneling probability is less than a preset carrier tunneling probability, the thickness of the GaN barrier layer is calculated. The specific calculation method of the GaN barrier layer thickness is as follows: ; Where, represents the thickness of the GaN barrier layer, P represents the carrier tunneling probability, ln represents the natural logarithm, E represents the carrier energy, represents the barrier height, that is, the energy band offset between the GaN barrier layer and the InGaN quantum well, C ∈ [ 0 . 6 , 0 . 7 ] represents the proportionality coefficient of the conduction band offset related to GaN and InGaN in the total bandgap difference, and respectively represent the GaN bandgap and the InGaN bandgap, represents the preset carrier tunneling probability.

[0031] Optionally, , C can specifically take 0.63.

[0032] It should be noted that by taking the carrier tunneling probability less than the preset tunneling probability as a constraint, it is ensured that during the operation of the device, carriers cannot pass through the barrier layer, avoiding unnecessary penetration of electrons or holes through the barrier, thereby improving the performance of the device. The thickness of the GaN barrier layer in the formula is related to factors such as carrier energy, barrier height, energy band offset, and bandgap difference. The reasonable design of these factors ensures the optimization of the GaN barrier layer. Through calculation, the thickness of the GaN barrier layer can be effectively controlled so that it can effectively isolate carriers without being too thick to affect the recombination efficiency of electrons or holes. This design helps to improve the light-emitting efficiency of the diode and the overall stability of the device, reduce energy loss, and ensure effective recombination of carriers in the quantum well.

[0033] In a possible implementation, the spacing distance is calculated by combining the effective refractive index of the total reflection layer and the target emission wavelength of the diode: ; where d represents the spacing distance, represents the target emission wavelength of the diode, represents the effective refractive index of the total reflection layer.

[0034] In a possible implementation, both the first electrode and the second electrode are electrodes composed of an Al bottom layer, a Ni bonding layer, and an Au top layer.

[0035] It should be noted that by calculating the spacing distance by combining the effective refractive index of the total reflection layer and the target emission wavelength of the diode, the design of the total reflection layer can be precisely optimized, thereby improving the light reflection efficiency and emission efficiency. Adjusting the spacing distance according to the target emission wavelength and the refractive index of the total reflection layer can ensure that the light reaches the best angle and propagation conditions during the reflection process, avoiding light loss. This optimization method not only improves the light extraction efficiency but also reduces the multiple scattering of light in the device, improving the overall light emission efficiency and photoelectric conversion efficiency of the diode.

[0036] In the actual application process, by calculating the spacing distance by combining the effective refractive index of the total reflection layer and the target emission wavelength of the diode, the design of the reflection layer can be precisely adjusted to optimize the light propagation path. This can ensure that the angle and conditions of the reflected light are most suitable for effectively returning to the quantum well region, thereby improving the light reflection efficiency and light extraction efficiency. This optimization method reduces light loss, avoids multiple scattering of light, and at the same time ensures that the light can be efficiently emitted from the diode, improving the overall light emission efficiency and photoelectric conversion efficiency of the diode. In this way, the performance of the diode is significantly improved, and the energy loss is effectively controlled.

[0037] Embodiment 2 In one embodiment, referring to the attached drawings of the specification Figure 2 , a schematic flow chart of a method for preparing an epitaxial structure of a gallium nitride-based diode provided by the present invention is shown.

[0038] A method for preparing an epitaxial structure of a gallium nitride-based diode provided by the present invention includes: S1: Sequentially grow a total reflection layer, a second ITO layer, an n-type GaN layer, multiple quantum wells, a p-type GaN layer, and a first ITO layer on a substrate.

[0039] Specifically, first, multiple layers are grown successively on a substrate (such as a sapphire substrate or an Si substrate). First is the total reflection layer, whose main function is to enhance the reflection of light and improve the light extraction efficiency. Then the second ITO layer is grown, which is a transparent conductive material for current injection and allows light to pass through. Next is the n-type GaN layer, which provides electrons, followed by the multiple quantum wells, which is the region where carriers recombine and emit light. Finally, the p-type GaN layer is responsible for providing holes to ensure the recombination of electrons and holes in the multiple quantum wells to emit light. The topmost is the first ITO layer, which is used to provide a current conduction path and allow light emission. The gradual growth of these layers ensures the efficient working performance of the device.

[0040] More specifically, a suitable substrate material is selected, usually a sapphire substrate or a Si substrate (silicon substrate). The substrate provides structural support and has an important influence on the epitaxial growth of subsequent layers. The total reflection layer is usually grown using a high refractive index material (such as AlGaN or AlN). The function of this layer is to reflect the light emitted from inside the diode back, reducing light loss and improving the light extraction efficiency. The growth method is usually metalorganic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE), which can precisely control the growth thickness and quality of the material. The second ITO layer (transparent conductive oxide layer) is used for current injection and allows light to pass through. This layer is usually deposited by sputtering or chemical vapor deposition (CVD). It has good conductivity and transparency, ensuring current injection and allowing the LED to emit light. The n-type GaN layer is the n-type material layer of the gallium nitride-based diode, used to provide electrons. It is usually grown by MOCVD using ammonia gas and metal organic compounds (such as trimethylaluminum, trimethylgallium). During this process, dopants (such as silicon (Si)) are used to control the electron concentration of n-type GaN. The multi-quantum well layer consists of periodically stacked InGaN quantum well layers and GaN barrier layers. The InGaN quantum well layer is used to improve the carrier recombination efficiency, and the GaN barrier layer is used to confine the movement of carriers in the quantum well and prevent them from escaping. This layer is usually grown using MOCVD technology to precisely control the thickness and composition between InGaN and GaN. The p-type GaN layer is used to provide holes and promote the recombination of electrons and holes in the quantum well. Usually, fluoride doping (such as Mg doping) is used to achieve p-type doping. The growth of this layer also uses MOCVD technology, and its conductivity is adjusted by controlling the doping concentration. Finally, the first ITO layer is also a transparent conductive oxide layer, having the same function as the second ITO layer, capable of both providing current conduction and allowing light emission. This layer is usually grown using the same deposition method as the second ITO layer (such as sputtering). Through this layer-by-layer growth method, the entire gallium nitride-based diode epitaxial structure is formed. The material of each layer plays a crucial role in the optical and electrical properties of the diode. By precisely controlling the growth thickness, doping concentration, and quality of each layer, the light emission efficiency, stability, and performance of the diode can be significantly improved.

[0041] In a possible implementation, the substrate is a sapphire substrate or a Si substrate.

[0042] S2: Generate an ohmic contact array on the total reflection layer through lithography technology.

[0043] It should be noted that an ohmic contact array is formed on the total reflection layer by lithography technology. The specific process is as follows: First, a photoresist is coated on the surface of the total reflection layer. Then, through the exposure and development processes, ultraviolet light (UV light) is used to irradiate a pre-designed mask pattern, and the required pattern is formed in the photoresist after exposure. Next, the unprotected areas of the photoresist are removed through an etching process to form a micro contact array. The design of these arrays enables the current to be evenly distributed in each area of the diode, ensuring good electrical contact and reducing the generation of local hot spots, thereby improving the performance and stability of the device.

[0044] S3: Remove the substrate.

[0045] In a possible implementation, the substrate is removed by chemical or mechanical methods.

[0046] Specifically, for the chemical method, acids or solvents can be used to dissolve the substrate (such as sapphire or Si substrate), or it can be removed by laser lift-off technology. The mechanical method may involve removing the substrate by cutting, grinding, or polishing. These methods can effectively remove the substrate and maintain the integrity of the epitaxial structure, providing the required light-emitting surface for subsequent electrode connection and packaging processes.

[0047] S4: Generate the first electrode and the second electrode.

[0048] Optionally, the generation of the first electrode and the second electrode is achieved through a metallization process. First, a metal material (such as aluminum, nickel, gold, etc.) is deposited on the surface of the diode using evaporation deposition or sputtering technology. These metal layers are used to form current channels to inject current into the p-type GaN layer (through the first electrode) and the n-type GaN layer (through the second electrode) respectively. Through the connection of these electrodes, current can be effectively injected into the active region of the diode to achieve light emission.

[0049] S5: Bond the conductive bracket to the second electrode to obtain the epitaxial structure of the gallium nitride-based diode.

[0050] In the actual application process, the epitaxial structure preparation method of the gallium nitride-based diode optimizes the performance of the diode through a precise multi-layer growth process and subsequent processing. First, a total reflection layer, a second ITO layer, an n-type GaN layer, multiple quantum wells, a p-type GaN layer, and a first ITO layer are sequentially grown on a substrate (sapphire or Si substrate). The gradual growth of these layers ensures the efficiency of current injection and light emission. An ohmic contact array is generated through photolithography technology, and the layout of the contact array is precisely controlled through an etching process to ensure uniform current distribution and reduce local hot spots. Then, the substrate is removed by chemical or mechanical methods to provide support for subsequent packaging and electrode connection. In the metallization process, the first and second electrodes are formed using evaporation deposition or sputtering technology to complete the construction of the current injection channel. Finally, a conductive bracket is bonded to the second electrode to obtain the final epitaxial structure of the gallium nitride-based diode. This method significantly improves the light emission efficiency, stability, and overall performance of the diode by optimizing light extraction, carrier recombination efficiency, and current uniform distribution.

[0051] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0052] The above embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. An epitaxial structure of a gallium nitride-based diode, characterized in that: include: A first electrode, a first ITO layer, a p-type GaN layer, a multi-quantum well, an n-type GaN layer, a second ITO layer, a total reflection layer, a second electrode and a conductive support; The first electrode, the first ITO layer, the p-type GaN layer, the multi-quantum well, the n-type GaN layer, the second ITO layer, the total reflection layer, the second electrode and the conductive support are stacked in sequence; The multiple quantum wells include periodically stacked InGaN quantum well layers and GaN barrier layers, wherein the GaN barrier layers are used to confine electrons and holes to the InGaN quantum well layers; An ohmic contact array is disposed on the total reflection layer in a penetrating manner, wherein the spacing distances between adjacent conductor media in the ohmic contact array are consistent; The second ITO is connected to the second electrode through the conductor medium. When the first electrode and the second electrode are connected, the electrons and holes generated by the p-type GaN layer and the n-type GaN layer recombine and emit light in the multi-quantum well.

2. The epitaxial structure of the gallium nitride-based diode according to claim 1, characterized in that: The p-type GaN layer is a Mg-doped p-type GaN layer, and the thickness of the p-type GaN layer is 120 nm; the n-type GaN layer is a Si-doped n-type GaN layer, and the thickness of the n-type GaN layer is 2 μm.

3. The epitaxial structure of the gallium nitride-based diode according to claim 1, characterized in that: The thickness of the first ITO layer and the second ITO layer are both 140 nm.

4. The epitaxial structure of the gallium nitride-based diode according to claim 1, characterized in that: Taking the target emission wavelength of the diode as a constraint, the thickness of the InGaN quantum well layer is determined in combination with the Schrödinger equation. The calculation formula for the thickness of the InGaN quantum well layer is specifically: ； in, represents the thickness of the InGaN quantum well layer, represents the reduced Planck constant, π represents the circumference of a circle, represents the effective mass of carriers, represents the energy difference of the quantized energy level n associated with InGaN, h represents Planck's constant, c represents the speed of light, Indicates the target emission wavelength, represents the band gap of InGaN.

5. The epitaxial structure of the gallium nitride-based diode according to claim 4, characterized in that: The thickness of the GaN barrier layer is calculated based on the constraint that the carrier tunneling probability is less than the preset carrier tunneling probability. The thickness of the GaN barrier layer is calculated as follows: ； in, represents the thickness of the GaN barrier layer, P represents the probability of carrier tunneling, ln represents the natural logarithm, E represents the carrier energy, represents the barrier height, i.e., the band offset between the GaN barrier layer and the InGaN quantum well. represents the ratio of the conduction band offset associated with GaN and InGaN to the total band gap difference, and represent GaN band gap and InGaN band gap respectively, Represents the preset carrier tunneling probability.

6. The epitaxial structure of the gallium nitride-based diode according to claim 1, characterized in that: The spacing distance is calculated by combining the effective refractive index of the total reflection layer and the target emission wavelength of the diode: ； Where d represents the spacing distance, Indicates the target emission wavelength of the diode, Represents the effective refractive index of the total reflection layer.

7. The epitaxial structure of the gallium nitride-based diode according to claim 1, characterized in that: The first electrode and the second electrode are both electrodes composed of an Al bottom layer, a Ni bonding layer and an Au top layer.

8. A method for preparing an epitaxial structure of a gallium nitride-based diode according to any one of claims 1 to 7, characterized in that: Methods include: S1: sequentially growing the total reflection layer, the second ITO layer, the n-type GaN layer, the multi-quantum well, the p-type GaN layer and the first ITO layer on a substrate; S2: Generating the ohmic contact array on the total reflection layer by photolithography technology; S3: removing the substrate; S4: generating the first electrode and the second electrode; S5: bonding the conductive support to the second electrode to obtain the epitaxial structure of the gallium nitride-based diode.

9. The preparation method according to claim 8, characterized in that: The substrate is a sapphire substrate or a Si substrate.

10. The preparation method according to claim 8, characterized in that: The substrate is removed chemically or mechanically.

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