Method for producing gallium nitride epitaxial wafer

Abstract

The application relates to a preparation method of a gallium nitride epitaxial wafer, which comprises the following steps: providing a substrate; growing a high-temperature gallium nitride core on the substrate; completing growth of a low-temperature gallium nitride nucleation layer on the substrate and the high-temperature gallium nitride core; completing three-dimensional growth of a gallium nitride island on the substrate, the high-temperature gallium nitride core and the low-temperature gallium nitride nucleation layer; and performing two-dimensional growth on the gallium nitride island, which solves the problem that the growth state of the gallium nitride epitaxial wafer is affected by the reaction cavity state of a metal organic chemical vapor deposition device.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a method for preparing gallium nitride epitaxial wafers. Background Technology

[0002] In recent years, Micro LEDs have been regarded as the next generation of display panel technology due to their superior performance in dynamic contrast, brightness, color gamut, and viewing angle, as well as their advantages in low power consumption and energy saving. With the continuous development of the semiconductor industry, third-generation semiconductors, represented by gallium nitride (GaN), possess characteristics such as high breakdown field strength, large bandgap, and high electron mobility, making them suitable for applications in high-frequency, high-voltage, high-power, high-temperature, and high-irradiation environments. They have enormous application prospects in 5G communications, radar, and electronic power. Therefore, GaN-based Micro LEDs have also sparked a research boom in full-color displays.

[0003] However, after years of development, the existing GaN epitaxial wafer growth methods have become relatively mature. However, the growth status of GaN epitaxial wafers is often greatly affected by the reaction chamber state of the metal-organic chemical vapor deposition (MOCVD) equipment. Moreover, the crystal quality of GaN prepared by different MOCVD equipment under the same process varies greatly. Therefore, it is still quite difficult to grow high-quality GaN on the substrate.

[0004] Therefore, how to obtain high-quality GaN on a substrate is an urgent problem to be solved. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this application is to provide a method for preparing gallium nitride epitaxial wafers, which aims to solve the problem that the growth state of gallium nitride epitaxial wafers is affected by the reaction chamber state of the metal-organic chemical vapor deposition equipment.

[0006] A method for fabricating a gallium nitride epitaxial wafer includes: providing a substrate; growing a high-temperature gallium nitride core on the substrate; growing a low-temperature gallium nitride nucleation layer on the substrate and the high-temperature gallium nitride core; growing a gallium nitride island in three dimensions on the substrate, the high-temperature gallium nitride core, and the low-temperature gallium nitride nucleation layer; and growing the gallium nitride island in two dimensions.

[0007] In summary, the gallium nitride epitaxial wafer fabrication method of this application provides stable nucleation sites for the three-dimensional growth of the gallium nitride islands using high-temperature gallium nitride nuclei, which are matched with the three-dimensional lattice of high-temperature gallium nitride. This results in a high-quality gallium nitride epitaxial wafer after the two-dimensional growth of the gallium nitride islands. Furthermore, the gallium nitride epitaxial wafer fabrication method of this application consumes less energy and reduces the dislocation density in the gallium nitride epitaxial wafer with minimal process variations, thereby obtaining a high-quality gallium nitride epitaxial wafer.

[0008] Optionally, the step of growing a high-temperature gallium nitride core on the substrate includes: cleaning the substrate; and growing the high-temperature gallium nitride core on the cleaned substrate.

[0009] Optionally, the cleaning process of the substrate includes: placing the substrate into the reaction chamber of a metal-organic chemical vapor deposition apparatus; cleaning the substrate at a first preset temperature and a first preset chamber pressure; wherein the first preset chamber pressure is 60-300 mbar and the first preset temperature is 950℃-1200℃.

[0010] Optionally, the step of growing the high-temperature gallium nitride nucleus on the cleaned substrate includes: simultaneously introducing ammonia and trimethylgallium into the reaction chamber of the metal-organic chemical vapor deposition apparatus under a first preset chamber pressure and for a first preset time, thereby growing the high-temperature gallium nitride nucleus on the cleaned substrate; stopping the input of trimethylgallium when the first preset time is reached; and continuously introducing ammonia under a second preset chamber pressure and for a second preset time to clean impurities and by-reaction products on the substrate surface and maintain the stable formation of the high-temperature gallium nitride nucleus; wherein the flow rate of trimethylgallium is 0.1-2.5 μmol / min, the flow rate of ammonia is 1-4.5 slm, the first preset time is 60-300 s, the second preset chamber pressure is 100-300 mbar, the second preset time is 20-120 s, and the second preset chamber pressure is greater than the first preset chamber pressure.

[0011] Optionally, the step of growing a low-temperature gallium nitride nucleation layer on the substrate and the high-temperature gallium nitride core includes: growing the low-temperature gallium nitride nucleation layer on the substrate and the high-temperature gallium nitride core; and annealing the low-temperature gallium nitride nucleation layer.

[0012] Optionally, the step of growing the low-temperature gallium nitride nucleation layer on the substrate and the high-temperature gallium nitride core includes: introducing trimethylgallium and ammonia into the reaction chamber of a metal-organic chemical vapor deposition apparatus at a second preset temperature and a third preset chamber pressure; and growing the low-temperature gallium nitride nucleation layer on the substrate and the high-temperature gallium nitride core; wherein the second preset temperature is 500℃-650℃, the third preset chamber pressure is 300-500mbar, the flow rate of trimethylgallium is 0.2-0.8μmol / min, and the flow rate of ammonia is 1-3slm.

[0013] Optionally, the annealing process for the low-temperature gallium nitride nucleation layer includes: annealing the generated low-temperature gallium nitride nucleation layer at a third preset temperature and a fourth preset chamber pressure for a third preset time; wherein the third preset time is 30-120s, the third preset temperature is 1020℃-1100℃, and the fourth preset chamber pressure is 150-350mbar.

[0014] Optionally, the three-dimensional growth of gallium nitride islands on the substrate, the high-temperature gallium nitride core, and the low-temperature gallium nitride nucleation layer includes: performing three-dimensional growth of gallium nitride islands on the substrate, the high-temperature gallium nitride core, and the low-temperature gallium nitride nucleation layer; and performing large-scale growth and lateral growth of the gallium nitride islands.

[0015] Optionally, the three-dimensional growth of gallium nitride islands on the substrate, the high-temperature gallium nitride core, and the low-temperature gallium nitride nucleation layer includes: continuously introducing trimethylgallium and ammonia into the reaction chamber of a metal-organic chemical vapor deposition apparatus; and performing three-dimensional growth of gallium nitride islands on the substrate, the high-temperature gallium nitride core, and the low-temperature gallium nitride nucleation layer under a fifth preset chamber pressure; wherein the fifth preset chamber pressure is 300-500 mbar, the flow rate of trimethylgallium is 1.2-2.5 μmol / min, and the flow rate of ammonia is 2.5-3.5 slm.

[0016] Optionally, the two-dimensional growth of the gallium nitride island includes: continuously introducing trimethylgallium and ammonia into the reaction chamber of a metal-organic chemical vapor deposition apparatus; performing two-dimensional growth on the gallium nitride island to obtain a corresponding gallium nitride epitaxial wafer; wherein the flow rate of trimethylgallium is 1.8-2.8 μmol / min, and the flow rate of ammonia is 3.0-5.0 slm.

[0017] In summary, the gallium nitride epitaxial wafer fabrication method of this application, by introducing a small amount of trimethylgallium and ammonia gas during the substrate treatment stage in a hydrogen atmosphere, can form low-density high-temperature gallium nitride nuclei on the substrate surface. These high-temperature gallium nitride nuclei can provide stable nucleation sites for the three-dimensional growth of gallium nitride islands and match the three-dimensional lattice of high-temperature gallium nitride. This allows for the formation of higher quality and larger gallium nitride islands after high-temperature annealing, thereby obtaining a high-quality gallium nitride epitaxial wafer after the two-dimensional growth of the gallium nitride islands. Furthermore, the gallium nitride epitaxial wafer fabrication method of this application has low energy consumption and can reduce the dislocation density in the gallium nitride epitaxial wafer with minimal process variations, thus obtaining a high-quality gallium nitride epitaxial wafer.

[0018] Based on the same inventive concept, this application also provides a display panel, which includes a display backplate and a gallium nitride epitaxial wafer prepared by the above-described gallium nitride epitaxial wafer preparation method, wherein the gallium nitride epitaxial wafer is mounted to the display backplate.

[0019] In summary, the display panel of this application, during the processing of the substrate in a hydrogen atmosphere by introducing a small amount of trimethylgallium and ammonia gas, can form low-density high-temperature gallium nitride nuclei on the surface of the substrate. These high-temperature gallium nitride nuclei can provide stable nucleation sites for the three-dimensional growth of gallium nitride islands and match the three-dimensional lattice of high-temperature gallium nitride. This allows for the formation of higher quality and larger gallium nitride islands after high-temperature annealing, resulting in a high-quality gallium nitride epitaxial wafer after the two-dimensional growth of the gallium nitride islands. Furthermore, the gallium nitride epitaxial wafer in the display panel of this application has a low dislocation density and high quality.

[0020] Based on the same inventive concept, this application also provides a display device, which includes a support frame and the above-described display panel, wherein the support frame is used to support the display panel.

[0021] In summary, during the processing of the substrate in a hydrogen atmosphere, a small amount of trimethylgallium and ammonia is introduced into the gallium nitride epitaxial wafer of the display panel in the display device of this application. This allows for the formation of low-density, high-temperature gallium nitride nuclei on the surface of the substrate. These high-temperature gallium nitride nuclei provide stable nucleation sites for the three-dimensional growth of the gallium nitride islands and match the three-dimensional lattice of high-temperature gallium nitride. This enables the formation of higher quality and larger gallium nitride islands after high-temperature annealing, resulting in a high-quality gallium nitride epitaxial wafer after the two-dimensional growth of the gallium nitride islands. Furthermore, the gallium nitride epitaxial wafer in the display device of this application exhibits a low dislocation density and high quality. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic flowchart of a method for preparing a gallium nitride epitaxial wafer disclosed in an embodiment of this application;

[0024] Figure 2 for Figure 1 A schematic diagram of the corresponding structure formed in step S10 of the preparation method shown;

[0025] Figure 3 for Figure 1 A schematic diagram of step S20 in the preparation method shown;

[0026] Figure 4 for Figure 3 The diagram shows the corresponding structure formed in step S21 of the preparation method shown.

[0027] Figure 5 for Figure 3 The diagram shows the corresponding structure formed in step S22 of the preparation method shown.

[0028] Figure 6 for Figure 1 A schematic diagram of step S30 in the preparation method shown;

[0029] Figure 7 for Figure 6 The diagram shows the corresponding structure formed in step S31 of the preparation method shown.

[0030] Figure 8 for Figure 6 The diagram shows the corresponding structure formed in step S32 of the preparation method shown.

[0031] Figure 9 for Figure 1 A schematic diagram of step S40 in the preparation method shown;

[0032] Figure 10 for Figure 9 The diagram shows the corresponding structure formed in step S41 of the preparation method shown.

[0033] Figure 11 for Figure 9 The diagram shows the corresponding structure formed in step S42 of the preparation method shown.

[0034] Figure 12 for Figure 1A schematic diagram of the corresponding structure formed in step S50 of the preparation method shown.

[0035] Explanation of reference numerals in the attached figures:

[0036] 10-Substrate;

[0037] 20-High-Temperature GaN Core;

[0038] 30-Low-temperature GaN nucleation layer;

[0039] 40-GaN islands;

[0040] 200-MOCVD equipment

[0041] 202-Reaction Chamber

[0042] The steps of the method for preparing S10-S50 gallium nitride epitaxial wafers;

[0043] S21-S22 - Step S20 in the method for preparing gallium nitride epitaxial wafers;

[0044] S31-S32 - Step S30 in the method for preparing gallium nitride epitaxial wafers;

[0045] Step S40 in the method for preparing gallium nitride epitaxial wafers (S41-S42). Detailed Implementation

[0046] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0048] In recent years, Micro LEDs have been regarded as the next generation of display panel technology due to their excellent performance in dynamic contrast, brightness, color gamut, and viewing angle, as well as their advantages in low power consumption and energy saving. With the continuous development of the semiconductor industry, third-generation semiconductors, represented by gallium nitride (GaN), possess characteristics such as high breakdown field strength, large bandgap, and high electron mobility, making them suitable for applications in high-frequency, high-voltage, high-power, high-temperature, and strong-irradiation environments. They have enormous application prospects in 5G communications, radar, and electronic power. Therefore, GaN-based Micro LEDs have also sparked a research boom in full-color displays. However, after years of development, existing GaN epitaxial wafer growth methods have become relatively mature. The growth status of GaN epitaxial wafers is often significantly affected by the reaction chamber state of the metal-organic chemical vapor deposition (MOCVD) equipment. Moreover, even with the same process, the crystal quality of GaN prepared by different MOCVD equipment reaction chambers varies considerably. Therefore, growing high-quality GaN on substrates remains a challenge. Therefore, how to solve the problem of the influence of the reaction chamber state of MOCVD equipment on the growth state of GaN epitaxial wafers in order to obtain high-quality GaN on the substrate is an urgent problem to be solved.

[0049] Based on this, this application aims to provide a solution that can solve the above-mentioned technical problems, which can solve the problem that the growth state of GaN epitaxial wafers is affected by the reaction chamber state of MOCVD equipment, thereby obtaining high-quality GaN on the substrate. The details will be described in subsequent embodiments.

[0050] This application provides a detailed description of a method for preparing a gallium nitride epitaxial wafer, a display panel, and a display device having the display panel.

[0051] Please see Figure 1 This is a schematic flowchart illustrating a method for preparing a gallium nitride epitaxial wafer disclosed in an embodiment of this application. The method is used to prepare a gallium nitride epitaxial wafer to improve the growth effect of gallium nitride (GaN) and thus obtain high-quality GaN. Figure 1 As shown in the embodiments of this application, the method for preparing the gallium nitride epitaxial wafer may include at least the following steps.

[0052] S10, Provide a substrate 10.

[0053] Specifically, in the embodiments of this application, such as Figure 2As shown, the substrate 10 can be an alumina (Al2O3) sapphire substrate or a silicon (Si) substrate. The substrate 10 has good optical properties, mechanical properties, chemical stability, mechanical properties, and thermal properties.

[0054] S20, a high-temperature GaN core 20 is grown on the substrate 10.

[0055] Specifically, in this embodiment, a high-temperature GaN core 20 is grown on the substrate 10.

[0056] Please see Figure 3 In this embodiment, step S20 may include at least the following steps.

[0057] S21. The substrate 10 is cleaned.

[0058] Specifically, please refer to Figure 4 The substrate 10 is placed in the reaction chamber 202 of the MOCVD equipment 200, and the substrate 10 is cleaned using a hydrogen atmosphere at a first preset temperature and a first preset chamber pressure to clean the surface of the substrate 10.

[0059] In this embodiment, the first preset chamber pressure can be 60-300 mbar, for example, 60 mbar, 70 mbar, 90 mbar, 100 mbar, 130 mbar, 170 mbar, 200 mbar, 240 mbar, 280 mbar, 300 mbar, or other values. The first preset temperature can be 950℃-1200℃, for example, 950℃, 1000℃, 1100℃, 1150℃, 1200℃, or other temperatures.

[0060] S22. The high-temperature GaN core 20 is grown on the cleaned substrate 10.

[0061] Specifically, please refer to Figure 5 After the substrate 10 is cleaned, ammonia (NH3) and trimethylgallium (TMGa) are simultaneously introduced into the reaction chamber 202 of the MOCVD equipment 200 under the first preset chamber pressure and for a first preset time, so that the high-temperature GaN core 20 is grown on the cleaned substrate 10; when the first preset time is reached, the input of TMGa is stopped; under the second preset chamber pressure and for a second preset time, NH3 is continuously introduced to ensure that impurities and by-reaction products on the surface of the substrate 10 are cleaned and to maintain the stable formation of the high-temperature GaN core 20.

[0062] In this embodiment, the flow rate of TMGa can be 0.1-2.5 μmol / min, for example, 0.1 μmol / min, 0.3 μmol / min, 0.6 μmol / min, 1.2 μmol / min, 1.5 μmol / min, 1.8 μmol / min, 2.5 μmol / min, or other values. The flow rate of NH3 can be 1-4.5 slm, for example, 1.0 slm, 1.2 slm, 1.5 slm, 2.0 slm, 2.5 slm, 3 slm, 3.5 slm, 4 slm, 4.3 slm, 4.5 slm, or other values. The first preset time can be 60-300 s, for example, 60 s, 80 s, 90 s, 100 s, 120 s, 150 s, 180 s, 200 s, 210 s, 240 s, 260 s, 270 s, 300 s, or other values. The second preset chamber pressure can be 100-300 mbar, for example, 100 mbar, 110 mbar, 150 mbar, 160 mbar, 180 mbar, 200 mbar, 210 mbar, 240 mbar, 270 mbar, 280 mbar, 300 mbar, or other values. The second preset time can be 20-120 s, for example, 20 s, 40 s, 50 s, 70 s, 100 s, 110 s, 120 s, or other values.

[0063] In this embodiment of the application, the second preset cavity pressure is greater than the first preset cavity pressure.

[0064] S30, the growth of the low-temperature GaN nucleation layer 30 is completed on the substrate 10 and the high-temperature GaN core 20.

[0065] Specifically, in this embodiment, after the high-temperature GaN core 20 is grown, the low-temperature GaN nucleation layer 30 is grown on the substrate 10 and the high-temperature GaN core 20.

[0066] Please see Figure 6 In this embodiment, step S30 may include at least the following steps.

[0067] S31. The low-temperature GaN nucleation layer 30 is grown on the substrate 10 and the high-temperature GaN core 20.

[0068] Specifically, please refer to Figure 7In this embodiment of the application, after the high-temperature GaN core 20 is grown, TMGa and NH3 are introduced into the reaction chamber 202 of the MOCVD equipment 200 at a second preset temperature and a third preset chamber pressure; the low-temperature GaN nucleation layer 30 is grown on the substrate 10 and the high-temperature GaN core 20, that is, part of the low-temperature GaN nucleation layer 30 is grown on the substrate 10 and part of the low-temperature GaN nucleation layer 30 is grown on the high-temperature GaN core 20.

[0069] It should be noted that the low-temperature GaN nucleation layer is mainly composed of disordered zincblende structures and amorphous states. During high-temperature annealing, it can decompose and react with NH3 to generate wurtzite GaN nuclei, which then grow into larger islands during GaN 3D growth.

[0070] In this embodiment, the second preset temperature can be 500℃-650℃, for example, 500℃, 520℃, 550℃, 580℃, 600℃, 625℃, 650℃, or other temperatures. The third preset chamber pressure can be 300-500 mbar, for example, 300 mbar, 330 mbar, 350 mbar, 370 mbar, 400 mbar, 420 mbar, 450 mbar, 480 mbar, 500 mbar, or other values. The flow rate of the TMGa can be 0.2-0.8 μmol / min, for example, 0.2 μmol / min, 0.25 μmol / min, 0.3 μmol / min, 0.36 μmol / min, 0.4 μmol / min, 0.45 μmol / min, 0.5 μmol / min, 0.56 μmol / min, 0.6 μmol / min, 0.55 μmol / min, 0.7 μmol / min, 0.75 μmol / min, 0.8 μmol / min, or other values. The flow rate of the NH3 can be 1-3 slm, for example, 1.0 slm, 1.3 slm, 1.5 slm, 1.7 slm, 2 slm, 2.4 slm, 2.5 slm, 3 slm, or other values.

[0071] S32. Anneal the low-temperature GaN nucleation layer 30.

[0072] Specifically, please refer to Figure 8 In this embodiment, the generated low-temperature GaN nucleation layer 30 is annealed for a third preset time under a third preset temperature and a fourth preset cavity pressure. Annealing releases stress in the low-temperature GaN nucleation layer 30 and increases its ductility and toughness.

[0073] In this embodiment, the third preset time can be 30-120s, for example, 30s, 50s, 60s, 90s, 100s, 110s, 120s, or other values. The third preset temperature can be 1020℃-1100℃, for example, 1020℃, 1040℃, 1050℃, 1060℃, 1080℃, 1090℃, 1100℃, or other temperatures. The fourth preset cavity pressure can be 150-350mbar, for example, 150mbar, 180mbar, 200mbar, 220mbar, 250mbar, 275mbar, 300mbar, 320mbar, 340mbar, 350mbar, or other values.

[0074] S40, complete the three-dimensional growth of GaN island 40 on the substrate 10, the high-temperature GaN core 20 and the low-temperature GaN nucleation layer 30.

[0075] Specifically, in this embodiment, after the growth of the low-temperature GaN nucleation layer 30 is completed, three-dimensional (3D) growth of GaN islands 40 is performed on the substrate 10, the high-temperature GaN core 20, and the low-temperature GaN nucleation layer 30. Thus, some of the GaN islands 40 are grown on the substrate 10, some on the high-temperature GaN core 20, and some on the low-temperature GaN nucleation layer 30. It should be noted that the density and quality of GaN islands are closely related to the dislocation density; therefore, the state of the GaN islands can be controlled to obtain a high-quality GaN epitaxial layer.

[0076] Please see Figure 9 In this embodiment, step S40 may include at least the following steps.

[0077] S41. Three-dimensional growth of GaN islands 40 is performed on the substrate 10, the high-temperature GaN core 20 and the low-temperature GaN nucleation layer 30.

[0078] Specifically, please refer to Figure 10 TMGa and NH3 are continuously introduced into the reaction chamber 202 of the MOCVD equipment 200. Under a fifth preset chamber pressure, GaN islands 40 are 3D grown on the substrate 10, the high-temperature GaN core 20, and the low-temperature GaN nucleation layer 30. That is, by continuously introducing TMGa and NH3 into the reaction chamber 202 of the MOCVD equipment 200 and under a set fifth preset chamber pressure, some GaN islands 40 grow on the substrate 10, some GaN islands 40 grow on the high-temperature GaN core 20, and some GaN islands 40 grow on the low-temperature GaN nucleation layer 30.

[0079] In this embodiment, the pressure of the fifth preset chamber can be 300-500 mbar, for example, 300 mbar, 330 mbar, 350 mbar, 370 mbar, 400 mbar, 420 mbar, 450 mbar, 480 mbar, 500 mbar, or other values. The flow rate of TMGa can be 1.2-2.5 μmol / min, for example, 1.2 μmol / min, 1.2 μmol / min, 1.5 μmol / min, 1.7 μmol / min, 1.8 μmol / min, 2.0 μmol / min, 2.1 μmol / min, 2.3 μmol / min, 2.5 μmol / min, or other values. The flow rate of NH3 can be 2.5-3.5 slm, for example, 2.5 slm, 2.6 slm, 2.8 slm, 3.0 slm, 3.1 slm, 3.3 slm, 3.5 slm, or other values.

[0080] S42, the GaN island 40 is grown and laterally grown.

[0081] Specifically, please refer to Figure 11 After the three-dimensional growth of GaN islands 40 on the substrate 10, the high-temperature GaN core 20, and the low-temperature GaN nucleation layer 30, TMGa and NH3 are continuously introduced into the reaction chamber 202 of the MOCVD equipment 200. Under the fifth preset chamber pressure, the GaN islands 40 undergo growth and lateral growth to complete the three-dimensional growth of the GaN islands 40. In the embodiments of this application, the growth can be the GaN islands 40 growing along a direction perpendicular to the substrate 10, and the lateral growth can be the GaN islands 40 growing along a direction parallel to the substrate 10.

[0082] S50, Perform two-dimensional growth on the GaN island 40.

[0083] Specifically, please refer to Figure 12 In this embodiment, after the three-dimensional growth of GaN islands 40 is completed on the substrate 10, the high-temperature GaN core 20, and the low-temperature GaN nucleation layer 30, TMGa and NH3 are continuously introduced into the reaction chamber of the MOCVD equipment. Under these growth conditions, the GaN islands 40 undergo two-dimensional (2D) growth to obtain the gallium nitride epitaxial wafer. In this embodiment, due to merging during the 2D growth of the GaN islands 40, some dislocations will appear in the GaN islands 40.

[0084] In this embodiment, the flow rate of TMGa can be 1.8-2.8 μmol / min, for example, 1.8 μmol / min, 1.9 μmol / min, 2.0 μmol / min, 2.2 μmol / min, 2.3 μmol / min, 2.4 μmol / min, 2.6 μmol / min, 2.7 μmol / min, 2.8 μmol / min, or other values. The flow rate of NH3 can be 3.0-5.0 slm, for example, 3.0 slm, 3.3 slm, 3.5 slm, 3.7 slm, 4.0 slm, 4.5 slm, 4.8 slm, 5.0 slm, or other values.

[0085] In summary, the gallium nitride epitaxial wafer fabrication method of this application, by introducing a small amount of TMGa and NH3 during the processing stage of the substrate 10 in a hydrogen atmosphere, can form low-density high-temperature GaN cores 20 on the surface of the substrate 10. These high-temperature GaN cores 20 can provide stable nucleation sites for the 3D growth of the GaN islands 40 and are matched with the high-temperature GaN 3D lattice, enabling the formation of higher quality and larger GaN islands 40 after high-temperature annealing. This results in a high-quality gallium nitride epitaxial wafer after the two-dimensional growth of the GaN islands 40. Furthermore, the gallium nitride epitaxial wafer fabrication method of this application has low energy consumption and can reduce the dislocation density in the gallium nitride epitaxial wafer with minimal process variations, thereby obtaining a high-quality gallium nitride epitaxial wafer.

[0086] This application also provides a display panel, which includes a display backplane and a gallium nitride epitaxial wafer prepared by the gallium nitride epitaxial wafer preparation method described in the above embodiments. The gallium nitride epitaxial wafer is used to prepare a light-emitting diode (LED). In other embodiments, the display panel may further include a display area and a non-display area. The LED is disposed in the display area for image display, and the non-display area is disposed around the display area and is not used for image display. The display panel may use liquid crystal material as the display medium, but this application is not limited thereto.

[0087] Understandably, the display panel can be used in electronic devices that include functions such as a Personal Digital Assistant (PDA) and / or a music player, such as mobile phones, tablets, and wearable electronic devices with wireless communication capabilities (such as smartwatches). The aforementioned electronic devices can also be other electronic devices, such as laptops with touch-sensitive surfaces (e.g., touch panels). In some embodiments, the electronic device may have communication capabilities, i.e., it can establish communication with a network via 2G (second-generation mobile communication technology), 3G (third-generation mobile communication technology), 4G (fourth-generation mobile communication technology), 5G (fifth-generation mobile communication technology), or W-LAN (wireless local area network) or other communication methods that may emerge in the future. For the sake of simplicity, this application embodiment does not further limit this aspect.

[0088] This application also provides a display device, which includes a support frame and a display panel as described in the above embodiments, wherein the support frame supports the display panel. The display device includes, but is not limited to, any electronic device or component with display function, such as a Mini LED panel, a Micro LED panel, a mobile phone, a tablet computer, a navigator, or a monitor; this application does not impose specific limitations on this. It is understood that the display device may further include: a pixel circuit disposed in the display area within the display panel for displaying images; and a circuit board assembly for providing operating voltage, driving current, and corresponding functional signals.

[0089] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing a gallium nitride epitaxial wafer, characterized in that, include: Provide a substrate; The process of growing high-temperature gallium nitride (GaN) nuclei on the substrate includes: simultaneously introducing ammonia and trimethylgallium (TMG) into the reaction chamber of a metal-organic chemical vapor deposition (MOCVD) apparatus under a first preset chamber pressure and for a first preset time, thereby growing the high-temperature GaN nuclei on the substrate; stopping the input of TMG when the first preset time is reached; and continuously introducing ammonia under a second preset chamber pressure and for a second preset time to clean impurities and by-reaction products on the substrate surface and maintain the stable formation of the high-temperature GaN nuclei; wherein the flow rate of TMG is 0.1-2.5 μmol / min, the flow rate of ammonia is 1-4.5 slm, the first preset time is 60-300 s, the second preset chamber pressure is 100-300 mbar, the second preset time is 20-120 s, and the second preset chamber pressure is greater than the first preset chamber pressure; A low-temperature gallium nitride (GaN) nucleation layer is grown on the substrate and the high-temperature GaN core, wherein a portion of the low-temperature GaN nucleation layer is grown on the substrate and a portion is grown on the high-temperature GaN core; the growth of the low-temperature GaN nucleation layer on the substrate and the high-temperature GaN core includes: growing the low-temperature GaN nucleation layer on the substrate and the high-temperature GaN core; and annealing the low-temperature GaN nucleation layer; Three-dimensional growth of gallium nitride islands is completed on the substrate, the high-temperature gallium nitride core, and the low-temperature gallium nitride nucleation layer. The high-temperature gallium nitride core provides nucleation sites for the three-dimensional growth of the gallium nitride islands. Some of the gallium nitride islands are grown on the substrate, some are grown on the high-temperature gallium nitride core, and some are grown on the low-temperature gallium nitride nucleation layer. The gallium nitride island is grown in two dimensions.

2. The method for preparing gallium nitride epitaxial wafers as described in claim 1, characterized in that, The process of growing a high-temperature gallium nitride core on the substrate includes: The substrate is cleaned. The high-temperature gallium nitride core is grown on the cleaned substrate.

3. The method for preparing gallium nitride epitaxial wafers as described in claim 2, characterized in that, The cleaning process for the substrate includes: The substrate is placed inside the reaction chamber of a metal-organic chemical vapor deposition apparatus; The substrate is cleaned at a first preset temperature and a first preset chamber pressure. The first preset chamber pressure is 60-300 mbar, and the first preset temperature is 950℃-1200℃.

4. The method for preparing a gallium nitride epitaxial wafer as described in claim 1, characterized in that, The process of growing the low-temperature gallium nitride nucleation layer on the substrate and the high-temperature gallium nitride core includes: At a second preset temperature and a third preset chamber pressure, trimethylgallium and ammonia gas are introduced into the reaction chamber of the metal-organic chemical vapor deposition equipment. The low-temperature gallium nitride nucleation layer is grown on the substrate and the high-temperature gallium nitride core; The second preset temperature is 500℃-650℃, the third preset chamber pressure is 300-500mbar, the flow rate of trimethylgallium is 0.2-0.8μmol / min, and the flow rate of ammonia is 1-3slm.

5. The method for preparing a gallium nitride epitaxial wafer as described in claim 1, characterized in that, The annealing process for the low-temperature gallium nitride nucleation layer includes: The generated low-temperature gallium nitride nucleation layer is annealed for a third preset time under a third preset temperature and a fourth preset cavity pressure. The third preset time is 30-120s, the third preset temperature is 1020℃-1100℃, and the fourth preset cavity pressure is 150-350mbar.

6. The method for preparing a gallium nitride epitaxial wafer as described in claim 1, characterized in that, The three-dimensional growth of gallium nitride islands on the substrate, the high-temperature gallium nitride core, and the low-temperature gallium nitride nucleation layer includes: Three-dimensional growth of gallium nitride islands is performed on the substrate, the high-temperature gallium nitride core, and the low-temperature gallium nitride nucleation layer; The gallium nitride islands are grown both vertically and laterally.

7. The method for preparing a gallium nitride epitaxial wafer as described in claim 6, characterized in that, The three-dimensional growth of gallium nitride islands on the substrate, the high-temperature gallium nitride core, and the low-temperature gallium nitride nucleation layer includes: Trimethylgallium and ammonia gas are continuously introduced into the reaction chamber of the metal-organic chemical vapor deposition equipment; Under the fifth preset cavity pressure, three-dimensional growth of gallium nitride islands is carried out on the substrate, the high-temperature gallium nitride core and the low-temperature gallium nitride nucleation layer; The fifth preset chamber pressure is 300-500 mbar, the flow rate of trimethylgallium is 1.2-2.5 μmol / min, and the flow rate of ammonia is 2.5-3.5 slm.

8. The method for preparing a gallium nitride epitaxial wafer as described in claim 1, characterized in that, The two-dimensional growth of the gallium nitride island includes: Trimethylgallium and ammonia gas are continuously introduced into the reaction chamber of the metal-organic chemical vapor deposition equipment; The gallium nitride islands are grown in two dimensions to obtain corresponding gallium nitride epitaxial wafers; The flow rate of trimethylgallium is 1.8-2.8 μmol / min, and the flow rate of ammonia is 3.0-5.0 slm.

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