GaN-based LED epitaxial wafer and preparation method thereof

Abstract

The invention provides a GaN-based LED epitaxial wafer and a preparation method thereof, and the method comprises the following steps: S1, providing a substrate, and placing the substrate on a graphite disc of an MOCVD reaction chamber; s2, carrying out heat treatment on the substrate; s3, growing a buffer layer on the substrate after heat treatment; s4, sequentially growing an unintentional doping layer and an N-type GaN layer on the buffer layer; s5, growing a multi-quantum well light-emitting layer on the N-type GaN layer; s6, growing a P-type electron blocking layer on the multi-quantum well light-emitting layer; step S7, growing a P-type GaN layer on the P-type electron barrier layer; and S8, after growing the P-type GaN layer, adjusting the temperature of the reaction chamber to 20-30 DEG C to obtain the GaN-based LED epitaxial wafer. The GaN-based LED epitaxial wafer obtained by the method has fewer surface particles and higher surface quality.

Description

Technical Field

[0001] This application belongs to the field of semiconductor technology, and particularly relates to a GaN-based LED epitaxial wafer and a preparation method thereof. Background Art

[0002] Micro LED generally refers to an LED device with a chip size smaller than 100 μm. The array composed of Micro LEDs has the advantages of low driving voltage, fast response speed, high resolution, etc. As the ultimate technology for ultra-high definition displays, Micro LEDs will be applied to application fields such as televisions, mobile phones, AR / VR, in-vehicle displays, wearable electronics, and digital displays in the future. Among them, wearable applications and high-end display applications will be the main entry points for Micro LEDs. Compared with other display technologies, Mini / Micro LED displays have obvious advantages in aspects such as contrast, response time, viewing angle, color gamut, brightness, power consumption efficiency, and resolution.

[0003] The manufacturing process of Micro LED mainly includes: epitaxy, chip manufacturing, mass transfer, packaging, and terminal applications, etc. Among them, epitaxy is the basis for Micro LED manufacturing. As the luminous size decreases, the influence of epitaxial quality on performance becomes more important, including the control of particles in the epitaxial wafer. The particles in the epitaxial wafer correspond to a defective pixel in the chip in Micro LED, which will increase the cost of subsequent chip layout and manufacturing, and directly affect the performance and reliability of Micro LED devices.

[0004] Regarding the control of particles in the epitaxial wafer, researchers at home and abroad have done a lot of research work, including the control of particles on the substrate surface, the cleanliness control of the factory building, the operation and maintenance of MOCVD equipment, and epitaxial technology, etc. However, the above can only partially solve the problem of surface particles and cannot meet the surface requirements of Micro LED. Therefore, new processes and technologies need to be proposed to further reduce surface particles and improve surface quality. Summary of the Invention

[0005] In view of this, this application provides a GaN-based LED epitaxial wafer and a preparation method thereof. The GaN-based LED epitaxial wafer prepared by this method has few surface particles and high surface quality.

[0006] In the first aspect, this application provides a method for preparing a GaN-based LED epitaxial wafer, including the following steps:

[0007] Step S1: Provide a substrate and place the substrate on a graphite disk in an MOCVD reaction chamber;

[0008] Step S2: Heat-treat the substrate. The conditions for the heat treatment include: the temperature of the heat treatment is 1000 - 1100 °C, the pressure in the reaction chamber is 80 - 120 torr, the hydrogen flow rate is 150 - 200 L / min, the rotation speed of the graphite disk is 900 - 1100 r / min, and the treatment time is 1 - 3 min;

[0009] Step S3: Grow a buffer layer on the heat-treated substrate. The conditions for growing the buffer layer include: the temperature in the reaction chamber is 800 - 1050 °C, the pressure in the reaction chamber is 50 - 100 torr, the nitrogen flow rate is 0 - 10 L / min, the hydrogen flow rate is 150 - 200 L / min, the ammonia flow rate is 5 - 30 L / min, the rotation speed of the graphite disk is 900 - 1100 r / min, and the growth thickness is 300 - 1000 nm;

[0010] Step S4: Sequentially grow an unintentionally doped layer and an N-type GaN layer on the buffer layer. The thickness of the unintentionally doped layer is 0.5 - 1 μm, and the thickness of the N-type GaN layer is 2 - 3 μm. The conditions for growing the unintentionally doped layer and the N-type GaN layer include: the temperature in the reaction chamber is 1050 - 1200 °C, the pressure in the reaction chamber is 150 - 200 torr, the nitrogen flow rate is 60 - 80 L / min, the hydrogen flow rate is 100 - 150 L / min, the ammonia flow rate is 40 - 80 L / min, and the rotation speed of the graphite disk is 1000 - 1200 r / min;

[0011] Step S5: Grow a multi-quantum well light-emitting layer on the N-type GaN layer. The conditions for growing the multi-quantum well light-emitting layer include: the temperature in the reaction chamber is 750 - 900 °C, the pressure in the reaction chamber is 200 - 300 torr, the nitrogen flow rate is 90 - 110 L / min, the hydrogen flow rate is 0 - 5 L / min, the ammonia flow rate is 80 - 120 L / min, and the rotation speed of the graphite disk is 1000 - 1200 r / min;

[0012] Step S6: Grow a P-type electron blocking layer on the multi-quantum well light-emitting layer. The conditions for growing the P-type electron blocking layer include: the temperature in the reaction chamber is 850 - 950 °C, the pressure in the reaction chamber is 100 - 150 torr, the nitrogen flow rate is 80 - 100 L / min, the hydrogen flow rate is 0 - 10 L / min, the ammonia flow rate is 10 - 20 L / min, and the rotation speed of the graphite disk is 800 - 1000 r / min;

[0013] Step S7: Grow a P-type GaN layer on the P-type electron blocking layer; wherein, the conditions for growing the P-type GaN layer include: the reaction chamber temperature is 950 - 1050 °C, the reaction chamber pressure is 400 - 600 torr, the nitrogen flow rate is 60 - 80 L / min, the hydrogen flow rate is 150 - 180 L / min, the ammonia flow rate is 60 - 80 L / min, and the graphite disk rotation speed is 900 - 1100 r / min;

[0014] Step S8: After growing the P-type GaN layer, adjust the reaction chamber temperature to 20 - 30 °C to obtain a GaN-based LED epitaxial wafer.

[0015] According to the present application, the GaN-based LED epitaxial wafer is obtained by successively passing through heat treatment, growth of a buffer layer, an unintentionally doped layer and an N-type GaN layer, a multi-quantum well light-emitting layer, a P-type electron blocking layer and a P-type GaN layer, and a temperature reduction stage. By controlling appropriate MOCVD deposition conditions, the obtained GaN-based LED epitaxial wafer has fewer surface particles and higher surface quality.

[0016] Specifically, in the present application, a thin film is deposited on the substrate surface by MOCVD. First, the substrate is heat-treated. Under the above conditions, heat treatment can effectively remove contaminants and oxides on the substrate surface, and at the same time activate the substrate surface, making it in a state conducive to the growth of the epitaxial layer. The increase in surface active sites is conducive to the uniform deposition of the epitaxial buffer layer. In addition, it can enhance the reaction chemistry of the gas in the reactor, accelerate the deposition process of the epitaxial material, make the distribution more uniform, and help quickly enter a stable growth state, avoiding fluctuations in the quality of the epitaxial layer or unstable growth caused by too low temperature;

[0017] In step S3, a buffer layer is grown on the heat-treated substrate. The buffer layer obtained under the above conditions has a relatively uniform structure, which can provide a smooth surface for the subsequent growth of the epitaxial layer; in addition, the buffer layer can improve the lattice mismatch problem between the substrate and the epitaxial layer, reduce the stress caused by the difference in lattice constants, thereby reducing the surface non-uniformity phenomenon; at the same time, the buffer layer obtained under the above conditions can adjust the deposition morphology of the epitaxial layer, control the generation of particles and defects, and thus improve the surface quality of the epitaxial wafer;

[0018] In step S4, an unintentionally doped layer and an N-type GaN layer are grown on the buffer layer. The unintentionally doped layer and the N-type GaN layer obtained under the above conditions have good surface quality. The unintentionally doped layer can serve as a transition layer, providing a stable and high-quality surface for the growth of the N-type GaN layer, thereby promoting the growth of N-type GaN and reducing defects caused by lattice constant differences. Additionally, under the above growth conditions, the growth rate of the N-type GaN layer is moderate, which can reduce the formation of particles due to too fast a growth rate and also reduce the uneven defects caused by too slow a growth rate, improving the surface quality of the epitaxial wafer.

[0019] In step S5, a multi-quantum well light-emitting layer is grown on the N-type GaN layer. By controlling appropriate growth temperature, growth pressure, gas flow rate, and graphite disk rotation speed, the multi-quantum well light-emitting layer has an appropriate deposition rate, reducing defects caused by an overly fast deposition rate resulting in incomplete material structures and reducing surface transition expansion and roughening caused by an overly slow deposition rate. Deposition under the above conditions can ensure a smooth transition between layers and reduce surface defects.

[0020] In step S6, a P-type electron blocking layer is grown on the multi-quantum well light-emitting layer. By controlling appropriate growth temperature, growth pressure, gas flow rate, and graphite disk rotation speed, the P-type electron blocking layer has an appropriate deposition rate, and a P-type electron blocking layer with uniform deposition and a flat surface can be obtained.

[0021] In step S7, a P-type GaN layer is grown on the P-type electron blocking layer. By controlling appropriate growth temperature, growth pressure, gas flow rate, and graphite disk rotation speed, the P-type GaN layer has an appropriate deposition rate, and a P-type GaN layer with uniform deposition and a flat surface can be obtained.

[0022] Finally, after the cooling stage, a GaN-based LED epitaxial wafer with few surface particles and high surface quality can be obtained.

[0023] In some embodiments, the substrate can be a material suitable for the growth of group III-V semiconductor materials, such as sapphire, silicon carbide, silicon, etc. As an example, in one embodiment of the present application, the substrate is Si.

[0024] In some embodiments, before the heat treatment in step S2, it includes: sequentially adjusting to the conditions of the heat treatment through the first stage to the fifth stage, where

[0025] The first stage includes: adjusting the reaction chamber pressure to 20 - 30 torr, adjusting the nitrogen flow rate to 10 - 20 L / min, increasing the graphite disk rotation speed to 100 - 200 r / min, and the duration is 1 - 2 min;

[0026] The second stage includes: adjusting the reaction chamber pressure to 80 - 120 torr, adjusting the nitrogen flow rate to 0 L / min, adjusting the hydrogen flow rate to 70 - 100 L / min, with a duration of 1 - 2 min;

[0027] The third stage includes: adjusting the nitrogen flow rate to 50 - 70 L / min, adjusting the hydrogen flow rate to 100 - 150 L / min, adjusting the rotation speed of the graphite disk to 500 - 700 r / min, with a duration of 1 - 2 min;

[0028] The fourth stage includes: adjusting the reaction chamber temperature to 500 - 600 °C, adjusting the rotation speed of the graphite disk to 900 - 1100 r / min, with a duration of 5 - 7 min;

[0029] The fifth stage includes: adjusting the reaction chamber temperature to 1000 - 1100 °C, adjusting nitrogen to 0 L / min, adjusting hydrogen to 150 - 200 L / min, adjusting the rotation speed of the graphite disk to 900 - 1000 r / min, with a duration of 7 - 10 min.

[0030] In some of the above embodiments, the reactor is adjusted to the heat treatment conditions through five stages. Since the surface quality stability of the substrate is poor before the growth of the buffer layer, by controlling the temperature, pressure, and atmosphere in segments, the substrate surface can gradually adapt to the changes in different stages, making the surface topography more uniform and preventing local surface unevenness, warping, or collapse of the substrate caused by too fast or uneven condition changes. Through the control of the above five stages, the uniformity of the surface topography during subsequent epitaxial growth can be effectively improved.

[0031] In some embodiments, before the step S3, before growing the buffer layer, it includes: sequentially passing through the first stage to the third stage to adjust from the heat treatment conditions to the conditions for growing the buffer layer, where,

[0032] The first stage includes: adjusting the reaction chamber pressure to 50 - 100 torr, adjusting the nitrogen flow rate to 0 - 10 L / min, with a duration of 1 - 2 min;

[0033] The second stage includes: adjusting the hydrogen flow rate to 150 - 200 L / min, adjusting the ammonia flow rate to 5 - 30 L / min, with a duration of 1 - 2 min;

[0034] The third stage includes: adjusting the rotation speed of the graphite disk to 900 - 1100 revolutions / min, adjusting the reaction chamber temperature to 800 - 1050 °C, with a duration of 1 - 2 min.

[0035] In some of the above embodiments, by adjusting the reactor to the conditions for growing the buffer layer in three stages, the pressure fluctuation in the reaction chamber can be reduced, the gas flow rate can be stabilized, the temperature in the reaction chamber can be evenly distributed, and the rotation speed of the graphite disk can be optimized, which can reduce the generation of particles during the deposition process.

[0036] In some embodiments, the buffer layer includes at least one of AlN, GaN, AlGaN, InAlGaN, and InGaN.

[0037] In some of the above embodiments, in step S4, before growing the unintentionally doped layer and the N-type GaN layer, it includes: sequentially passing through the first stage to the third stage to adjust from the conditions of the growth buffer layer to the conditions of growing the unintentionally doped layer and the N-type GaN layer, where

[0038] The first stage includes: adjusting the reaction chamber pressure to 150 - 200 torr, adjusting the nitrogen gas flow rate to 60 - 80 L / min, and the duration is 2 - 3 min;

[0039] The second stage includes: adjusting the hydrogen gas flow rate to 100 - 150 L / min, adjusting the ammonia gas flow rate to 40 - 80 L / min, and the duration is 2 - 3 min;

[0040] The third stage includes: adjusting the rotation speed of the graphite disk to 1000 - 1200 r / min, adjusting the reaction chamber temperature to 1050 - 1200 °C, and the duration is 3 - 4 min.

[0041] In some of the above embodiments, by adjusting the reactor to the conditions for growing the unintentionally doped layer and the N-type GaN layer in three stages, the pressure fluctuation in the reaction chamber can be reduced, the gas flow rate can be stabilized, the temperature in the reaction chamber can be evenly distributed, and the rotation speed of the graphite disk can be optimized, which can reduce the generation of particles during the deposition process.

[0042] In some embodiments, the unintentionally doped layer includes at least one of AlN, GaN, AlGaN, InAlGaN, and InGaN.

[0043] In some embodiments, the N-type GaN layer includes at least one of AlN, GaN, AlGaN, InAlGaN, and InGaN doped with an electron-donating impurity. The electron-donating impurity can be Si.

[0044] In some embodiments, in step S5, before growing the multiple quantum well light-emitting layer, it includes: sequentially passing through the first stage to the third stage to reach the conditions for growing the multiple quantum well light-emitting layer from the conditions of the growth unintentionally doped layer and the N-type GaN layer, where

[0045] The first stage includes: adjusting the reaction chamber pressure to 200 - 300 torr, adjusting the nitrogen flow rate to 90 - 110 L / min, with a duration of 2 - 3 min;

[0046] The second stage includes: adjusting the hydrogen flow rate to 0 - 5 L / min, adjusting the ammonia flow rate to 80 - 120 L / min, with a duration of 3 - 4 min;

[0047] The third stage includes: adjusting the rotation speed of the graphite disk to 1000 - 1200 r / min, adjusting the reaction chamber temperature to 750 - 900 °C, with a duration of 3 - 4 min.

[0048] In some of the above embodiments, by adjusting the reactor to the conditions for growing the multi - quantum well light - emitting layer in three stages, the pressure fluctuation in the reaction chamber can be reduced, the gas flow rate can be stabilized, the temperature in the reaction chamber can be evenly distributed, and the rotation speed of the graphite disk can be optimized, which can reduce the generation of particles during the deposition process.

[0049] In some embodiments, the structure of the multi - quantum well light - emitting layer is (Al x Ga 1-x N / In y Ga 1-y N) n where Al x Ga 1-x N is the barrier, the component x can be between 0 and 0.4, and the thickness is 3 - 5 nm; In y Ga 1-y N is the well, the component y can be between 0 and 0.3, and the thickness is 2 - 4 nm; the number of periods n is 3 - 6.

[0050] In some of the above embodiments, when the multi - quantum well light - emitting layer is composed of the above structure, the defects caused by band mismatch can be reduced, the flatness between layers can be improved, thereby reducing surface defects and improving surface quality.

[0051] In some embodiments, in step S6, before growing the P - type electron blocking layer, it includes: successively going through the first stage to the third stage to adjust from the conditions for growing the multi - quantum well light - emitting layer to the conditions for growing the P - type electron blocking layer, where

[0052] The first stage includes: adjusting the reaction chamber pressure to 100 - 150 torr, adjusting the nitrogen flow rate to 80 - 100 L / min, with a duration of 2 - 3 min;

[0053] The second stage includes: adjusting the hydrogen flow rate to 0 - 10 L / min, adjusting the ammonia flow rate to 10 - 20 L / min, with a duration of 3 - 4 min;

[0054] The third stage includes: adjusting the rotation speed of the graphite disk to 800 - 1000 r / min, adjusting the temperature of the reaction chamber to 850 - 950 °C, and the duration is 2 - 3 min.

[0055] In some of the above embodiments, by adjusting the reactor to the conditions for growing the P-type electron blocking layer (EBL, Electron Blocking Layer) in three stages, the pressure fluctuation in the reaction chamber can be reduced, the gas flow rate can be stabilized, the temperature in the reaction chamber can be evenly distributed, and the rotation speed of the graphite disk can be optimized, thereby reducing the generation of particles during the deposition process.

[0056] In some embodiments, the P-type electron blocking layer includes at least one of pGaN, pAlGaN, pAlInGaN, and pAlN doped with Mg element.

[0057] In some embodiments, the thickness of the P-type electron blocking layer is 20 - 50 nm, and the doping concentration of the Mg element is 5×10 18 ~3.5×10 19 cm -3 。

[0058] In some embodiments, in step S7, before growing the P-type GaN layer, it includes: adjusting from the conditions for growing the P-type electron blocking layer to the conditions for growing the P-type GaN layer through the first stage to the third stage in sequence, where

[0059] The first stage includes: adjusting the pressure in the reaction chamber to 400 - 600 torr, adjusting the nitrogen gas flow rate to 60 - 80 L / min, and the duration is 3 - 4 min;

[0060] The second stage includes: adjusting the hydrogen gas flow rate to 150 - 180 L / min, adjusting the ammonia gas flow rate to 60 - 80 L / min, and the duration is 3 - 4 min;

[0061] The third stage includes: adjusting the rotation speed of the graphite disk to 900 - 1100 r / min, adjusting the temperature of the reaction chamber to 950 - 1050 °C, and the duration is 2 - 3 min.

[0062] In some of the above embodiments, by adjusting the reactor to the conditions for growing the P-type GaN layer in three stages, the pressure fluctuation in the reaction chamber can be reduced, the gas flow rate can be stabilized, the temperature in the reaction chamber can be evenly distributed, and the rotation speed of the graphite disk can be optimized, thereby reducing the generation of particles during the deposition process.

[0063] In some embodiments, the P-type GaN layer is pGaN doped with Mg element, the thickness of the pGaN doped with Mg element is 30 - 60 nm, and the doping concentration of the Mg element is 5×10 18 ~1×1020 cm -3 。

[0064] In some of the above embodiments, adjusting the reaction chamber temperature to 20-30°C after growing the P-type GaN layer includes: successively passing through the first stage to the sixth stage to adjust from the conditions for growing the P-type electron blocking layer to a reaction chamber temperature of 20-30°C, where,

[0065] The first stage includes: adjusting the reaction chamber pressure to 150-200 torr, with a duration of 2-3 min;

[0066] The second stage includes: adjusting the nitrogen flow rate to 120-150 L / min, the hydrogen flow rate to 0 L / min, and the ammonia flow rate to 0 L / min, with a duration of 3-4 min;

[0067] The third stage includes: adjusting the rotation speed of the graphite disk to 600-700 r / min, with a duration of 2-3 min;

[0068] The fourth stage includes: adjusting the reaction chamber temperature to 700-800°C, with a duration of 2-3 min;

[0069] The fifth stage includes: adjusting the reaction chamber temperature to 400-500°C, with a duration of 5-10 min;

[0070] The sixth stage includes: adjusting the reaction chamber temperature to 20-30°C for 5-10 min.

[0071] In some of the above embodiments, adjusting the reactor to 20-30°C through six stages can avoid problems such as thermal stress accumulation, increased surface roughness, and cracks during the cooling process, help repair the crystal curve, reduce internal stress, and improve the surface quality, thereby further improving the surface quality of the epitaxial wafer.

[0072] In a second aspect, the present application provides a GaN-based LED epitaxial wafer prepared by the method according to any one of the embodiments in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 It is a schematic structural diagram of a GaN-based LED epitaxial wafer provided by the present application.

[0074] Figure 2 It is a microscopic photograph of the surface of the GaN-based LED epitaxial wafer obtained in Example 1 of the present application.

[0075] Figure 3 It is a microscopic photograph of the surface of the GaN-based LED epitaxial wafer obtained in Example 2 of the present application.

[0076] Figure 4 This is a microscope photograph of the surface of the GaN-based LED epitaxial wafer obtained in Comparative Example 1 of this application. Detailed implementation manners

[0077] In order to make the objectives, technical solutions and advantages of this application more clear and understandable, the following further elaborates on this application in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely used to explain this application and are not used to limit this application.

[0078] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of this application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0079] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this application, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0080] The following elaborates on the solutions of this application in conjunction with the following specific embodiments. Unless otherwise specified, the raw materials used in the following embodiments are all from ordinary commercially available products, and the devices or equipment used are all purchased from conventional market sales channels.

[0081] Embodiment 1

[0082] Preparation of GaN-based LED epitaxial wafer:

[0083] The structural schematic diagram of the GaN-based LED epitaxial wafer is as Figure 1 shown. Specifically,

[0084] Step S1:

[0085] Provide a substrate Si and place the substrate on the graphite disk in the MOCVD reaction chamber;

[0086] Step S2:

[0087] Adjust the conditions of the MOCVD reaction chamber to the heat treatment conditions through the following five stages:

[0088] The first stage: The pressure in the reaction chamber is adjusted to 20 torr, the nitrogen flow rate is adjusted to 10 L / min, the rotational speed of the graphite disk is increased to 100 r / min, and the duration is 2 min;

[0089] The second stage: The pressure in the reaction chamber is adjusted to 80 torr, the nitrogen flow rate is adjusted to 0 L / min, the hydrogen flow rate is adjusted to 70 L / min, and the duration is 2 min;

[0090] The third stage: The nitrogen flow rate is adjusted to 50 L / min, the hydrogen flow rate is adjusted to 100 L / min, the rotational speed of the graphite disk is adjusted to 500 r / min, and the duration is 2 min;

[0091] The fourth stage: The temperature in the reaction chamber is adjusted to 500 °C, the rotational speed of the graphite disk is adjusted to 900 r / min, and the duration is 7 min;

[0092] The fifth stage: The temperature in the reaction chamber is adjusted to 1100 °C, nitrogen is adjusted to 0 L / min, hydrogen is adjusted to 200 L / min, the rotational speed of the graphite disk is adjusted to 1000 r / min, and the duration is 10 min;

[0093] At this time, the conditions of the MOCVD reaction chamber are: the temperature is 1100 °C, the pressure in the reaction chamber is 120 torr, the hydrogen flow rate is 200 L / min, and the rotational speed of the graphite disk is 1000 r / min;

[0094] Heat treatment is carried out under these conditions, and the treatment time is 3 min;

[0095] Step S3:

[0096] The MOCVD reaction chamber is adjusted from the heat treatment conditions to the growth buffer layer conditions through the following three stages:

[0097] The first stage: The pressure in the reaction chamber is adjusted to 50 torr, the nitrogen flow rate is adjusted to 5 L / min, and the duration is 2 min;

[0098] The second stage: The hydrogen flow rate is adjusted to 150 L / min, the ammonia flow rate is adjusted to 10 L / min, and the duration is 2 min;

[0099] The third stage: The rotational speed of the graphite disk is adjusted to 1100 r / min, the temperature in the reaction chamber is adjusted to 1050 °C, and the duration is 2 min;

[0100] At this time, the conditions of the MOCVD reaction chamber are: the temperature in the reaction chamber is 1050 °C, the pressure in the reaction chamber is 50 torr, the nitrogen flow rate is 5 L / min, the hydrogen flow rate is 150 L / min, the ammonia flow rate is 10 L / min, and the rotational speed of the graphite disk is 1100 r / min;

[0101] Under such conditions, a buffer layer of AlN and AlGaN is grown on the heat-treated substrate, with thicknesses of 300 nm and 500 nm respectively.

[0102] Step S4:

[0103] The MOCVD reaction chamber is adjusted from the conditions for growing the buffer layer to the conditions for growing the unintentionally doped layer and the N-type GaN layer through the following three stages:

[0104] The first stage: The reaction chamber pressure is adjusted to 150 torr, the nitrogen flow rate is adjusted to 60 L / min, and the duration is 3 min;

[0105] The second stage: The hydrogen flow rate is adjusted to 100 L / min, the ammonia flow rate is adjusted to 40 L / min, and the duration is 3 min;

[0106] The third stage: The rotation speed of the graphite disk is adjusted to 1200 r / min, the reaction chamber temperature is adjusted to 1050 °C, and the duration is 4 min;

[0107] At this time, the conditions of the MOCVD reaction chamber are: the reaction chamber temperature is 1050 °C, the reaction chamber pressure is 150 torr, the nitrogen flow rate is 60 L / min, the hydrogen flow rate is 100 L / min, the ammonia flow rate is 40 L / min, and the rotation speed of the graphite disk is 1200 r / min;

[0108] Under such conditions, an unintentionally doped layer and an N-type GaN layer are sequentially grown on the buffer layer. Among them, the thickness of the unintentionally doped layer is 1 μm, the thickness of the N-type GaN layer is 2 μm, the unintentionally doped layer is GaN, and the N-type GaN layer is GaN doped with Si, and the doping concentration is 1×10 19 cm -3 ;

[0109] Step S5:

[0110] The MOCVD reaction chamber is adjusted from the conditions for growing the unintentionally doped layer and the N-type GaN layer to the conditions for growing the multi-quantum well light-emitting layer through the following three stages:

[0111] The first stage: The reaction chamber pressure is adjusted to 200 torr, the nitrogen flow rate is adjusted to 90 L / min, and the duration is 3 min;

[0112] The second stage: The hydrogen flow rate is adjusted to 0 L / min, the ammonia flow rate is adjusted to 80 L / min, and the duration is 4 min;

[0113] The third stage: The rotation speed of the graphite disk is adjusted to 1000 r / min, the reaction chamber temperature is adjusted to 830 °C, and the duration is 4 min;

[0114] At this time, the conditions of the MOCVD reaction chamber are as follows: the reaction chamber temperature is 830 °C and 760 °C, which are the growth temperatures of the barrier and the well respectively, the reaction chamber pressure is 200 torr, the nitrogen flow rate is 90 L / min, the hydrogen flow rate is 0 L / min, the ammonia flow rate is 80 L / min, and the graphite disk rotation speed is 1000 r / min;

[0115] Under these conditions, a multi-quantum well light-emitting layer is grown on the N-type GaN layer. Among them, the structure of the multi-quantum well light-emitting layer is (Al x Ga 1-x N / In y Ga 1-y N) n Among them, Al x Ga 1-x N is the barrier, the component x is 0.05, and the thickness is 3 nm; In y Ga 1-y N is the well, the component y is 0.16, and the thickness is 3 nm; the number of periods n is 6;

[0116] Step S6:

[0117] The MOCVD reaction chamber is adjusted from the conditions for growing the multi-quantum well light-emitting layer to the conditions for growing the P-type electron blocking layer through the following three stages:

[0118] The first stage: the reaction chamber pressure is adjusted to 100 torr, the nitrogen flow rate is adjusted to 80 L / min, and the duration is 3 min;

[0119] The second stage: the hydrogen flow rate is adjusted to 5 L / min, the ammonia flow rate is adjusted to 10 L / min, and the duration is 4 min;

[0120] The third stage: the graphite disk rotation speed is adjusted to 800 r / min, and the reaction chamber temperature is adjusted to 900 °C, and the duration is 3 min;

[0121] At this time, the conditions of the MOCVD reaction chamber are as follows: the reaction chamber temperature is 900 °C, the reaction chamber pressure is 100 torr, the nitrogen flow rate is 80 L / min, the hydrogen flow rate is 5 L / min, the ammonia flow rate is 10 L / min, and the graphite disk rotation speed is 800 r / min;

[0122] Under these conditions, a P-type electron blocking layer (EBL) is grown on the multi-quantum well light-emitting layer. Among them, the P-type electron blocking layer is pGaN doped with Mg, and the doping concentration is 3.5×10 19 cm -3 ⁻³, and the thickness of the P-type electron blocking layer is 30 nm;

[0123] Step S7:

[0124] The MOCVD reaction chamber is adjusted from the conditions for growing the P-type electron blocking layer to the conditions for growing the P-type GaN layer through the following three stages:

[0125] The first stage: The reaction chamber pressure is adjusted to 500 torr, the nitrogen flow rate is adjusted to 60 L / min, and the duration is 4 min;

[0126] The second stage: The hydrogen flow rate is adjusted to 150 L / min, the ammonia flow rate is adjusted to 60 L / min, and the duration is 4 min;

[0127] The third stage: The rotation speed of the graphite disk is adjusted to 900 r / min, the reaction chamber temperature is adjusted to 950 °C, and the duration is 3 min;

[0128] At this time, the conditions of the MOCVD reaction chamber are: the reaction chamber temperature is 950 °C, the reaction chamber pressure is 500 torr, the nitrogen flow rate is 60 L / min, the hydrogen flow rate is 150 L / min, the ammonia flow rate is 60 L / min, and the rotation speed of the graphite disk is 900 r / min;

[0129] The P-type GaN layer is grown on the P-type electron blocking layer under these conditions; among them, the P-type electron blocking layer is pGaN doped with Mg, and the doping concentration is 3×10 19 cm -3 , and the thickness of the P-type layer is 60 nm;

[0130] Step S8:

[0131] The MOCVD reaction chamber is adjusted from the conditions for growing the P-type electron blocking layer to a reaction chamber temperature of 25 °C through the following six stages:

[0132] The first stage: The reaction chamber temperature is adjusted to 750 °C, and the duration is 3 min;

[0133] The second stage: The reaction chamber pressure is adjusted to 200 torr, and the duration is 3 min;

[0134] The third stage: The nitrogen flow rate is adjusted to 120 L / min, the hydrogen flow rate is adjusted to 0 L / min, the ammonia flow rate is adjusted to 0 L / min, and the duration is 4 min;

[0135] The fourth stage: The rotation speed of the graphite disk is adjusted to 700 r / min, and the duration is 3 min;

[0136] The fifth stage: The reaction chamber temperature is adjusted to 500 °C, the rotation speed of the graphite disk is adjusted to 500 r / min, and the duration is 5 min;

[0137] Sixth stage: The temperature of the reaction chamber is adjusted to 25 °C, the rotation speed of the graphite disk is adjusted to 0 r / min, and the time is 10 min;

[0138] At this time, the GaN-based LED epitaxial wafer is obtained.

[0139] Example 2

[0140] Preparation of GaN-based LED epitaxial wafer:

[0141] The structural schematic diagram of the GaN-based LED epitaxial wafer is as Figure 1 shown. Specifically,

[0142] Step S1:

[0143] Provide a substrate Si and place the substrate on the graphite disk in the MOCVD reaction chamber;

[0144] Step S2:

[0145] Adjust the conditions of the MOCVD reaction chamber to the heat treatment conditions through the following three stages:

[0146] First stage: The reaction chamber pressure is adjusted to 80 torr, the nitrogen flow rate is adjusted to 0 L / min, the hydrogen flow rate is adjusted to 70 L / min, and the duration is 2 min;

[0147] Second stage: The nitrogen flow rate is adjusted to 50 L / min, the hydrogen flow rate is adjusted to 100 L / min, the rotation speed of the graphite disk is adjusted to 500 r / min, and the duration is 2 min;

[0148] Third stage: The reaction chamber temperature is adjusted to 1100 °C, nitrogen is adjusted to 0 L / min, hydrogen is adjusted to 200 L / min, the rotation speed of the graphite disk is adjusted to 1000 r / min, and the duration is 10 min;

[0149] At this time, the conditions of the MOCVD reaction chamber are: the temperature is 1100 °C, the reaction chamber pressure is 120 torr, the hydrogen flow rate is 200 L / min, and the rotation speed of the graphite disk is 1000 r / min;

[0150] Heat treatment is carried out under these conditions, and the treatment time is 3 min;

[0151] Step S3:

[0152] Adjust the MOCVD reaction chamber from the heat treatment conditions to the growth buffer layer conditions through the following two stages:

[0153] First stage: The reaction chamber pressure is adjusted to 50 torr, the nitrogen flow rate is adjusted to 5 L / min, the hydrogen flow rate is adjusted to 150 L / min, the ammonia flow rate is adjusted to 10 L / min, and the duration is 2 min;

[0154] The second stage: Adjust the rotation speed of the graphite disk to 1100 revolutions per minute, adjust the reaction chamber temperature to 1050 °C, and the duration is 2 minutes;

[0155] At this time, the conditions of the MOCVD reaction chamber are: the reaction chamber temperature is 1050 °C, the reaction chamber pressure is 50 torr, the nitrogen flow rate is 5 L / min, the hydrogen flow rate is 150 L / min, the ammonia flow rate is 10 L / min, and the rotation speed of the graphite disk is 1100 r / min;

[0156] Under these conditions, a buffer layer of AlN and AlGaN is grown on the heat-treated substrate, with thicknesses of 300 nm and 500 nm respectively;

[0157] Step S4:

[0158] The MOCVD reaction chamber is adjusted from the conditions for growing the buffer layer to the conditions for growing the unintentionally doped layer and the N-type GaN layer through the following two stages:

[0159] The first stage: Adjust the reaction chamber pressure to 150 torr, adjust the nitrogen flow rate to 60 L / min, adjust the hydrogen flow rate to 100 L / min, adjust the ammonia flow rate to 40 L / min, and the duration is 3 minutes;

[0160] The second stage: Adjust the rotation speed of the graphite disk to 1200 r / min, adjust the reaction chamber temperature to 1050 °C, and the duration is 4 minutes;

[0161] At this time, the conditions of the MOCVD reaction chamber are: the reaction chamber temperature is 1050 °C, the reaction chamber pressure is 150 torr, the nitrogen flow rate is 60 L / min, the hydrogen flow rate is 100 L / min, the ammonia flow rate is 40 L / min, and the rotation speed of the graphite disk is 1200 r / min;

[0162] Under these conditions, an unintentionally doped layer and an N-type GaN layer are sequentially grown on the buffer layer. Among them, the thickness of the unintentionally doped layer is 1 μm, the thickness of the N-type GaN layer is 2 μm, the unintentionally doped layer is GaN, the N-type GaN layer is GaN doped with Si, and the doping concentration is 1×10 19 cm -3 ;

[0163] Step S5:

[0164] The MOCVD reaction chamber is adjusted from the conditions for growing the unintentionally doped layer and the N-type GaN layer to the conditions for growing the multi-quantum well light-emitting layer through the following two stages:

[0165] The first stage: The pressure in the reaction chamber is adjusted to 200 torr, the nitrogen flow rate is adjusted to 90 L / min, the hydrogen flow rate is adjusted to 0 L / min, the ammonia flow rate is adjusted to 80 L / min, and the duration is 4 min;

[0166] The second stage: The rotation speed of the graphite disk is adjusted to 1000 r / min, the temperature in the reaction chamber is adjusted to 830 °C, and the duration is 4 min;

[0167] At this time, the conditions of the MOCVD reaction chamber are: the temperature in the reaction chamber is 830 °C and 760 °C, which are the growth temperatures of the barrier and the quantum well respectively, the pressure in the reaction chamber is 200 torr, the nitrogen flow rate is 90 L / min, the hydrogen flow rate is 0 L / min, the ammonia flow rate is 80 L / min, and the rotation speed of the graphite disk is 1000 r / min;

[0168] Under these conditions, a multi-quantum well light-emitting layer is grown on the N-type GaN layer. Among them, the structure of the multi-quantum well light-emitting layer is (Al x Ga 1-x N / In y Ga 1-y N) n Among them, Al x Ga 1-x N is the barrier, the component x is 0.05, and the thickness is 5 nm; In y Ga 1-y N is the quantum well, the component y is 0.16, and the thickness is 3 nm; the number of periods n is 6;

[0169] Step S6:

[0170] The MOCVD reaction chamber is adjusted from the conditions for growing the multi-quantum well light-emitting layer to the conditions for growing the P-type electron blocking layer through the following two stages:

[0171] The first stage: The pressure in the reaction chamber is adjusted to 100 torr, the nitrogen flow rate is adjusted to 80 L / min, the hydrogen flow rate is adjusted to 5 L / min, the ammonia flow rate is adjusted to 10 L / min, and the duration is 4 min;

[0172] The second stage: The rotation speed of the graphite disk is adjusted to 800 r / min, the temperature in the reaction chamber is adjusted to 900 °C, and the duration is 3 min;

[0173] At this time, the conditions of the MOCVD reaction chamber are: the temperature in the reaction chamber is 900 °C, the pressure in the reaction chamber is 100 torr, the nitrogen flow rate is 80 L / min, the hydrogen flow rate is 5 L / min, the ammonia flow rate is 10 L / min, and the rotation speed of the graphite disk is 800 r / min;

[0174] Under such conditions, a P-type electron blocking layer (EBL) is grown on the multi-quantum well light-emitting layer. The P-type electron blocking layer is pGaN doped with Mg, and the doping concentration is 3.5×10 19 cm -3 , and the thickness of the P-type electron blocking layer is 30 nm;

[0175] Step S7:

[0176] The MOCVD reaction chamber is adjusted from the conditions for growing the P-type electron blocking layer to the conditions for growing the P-type GaN layer through the following two stages:

[0177] The first stage: The reaction chamber pressure is adjusted to 500 torr, the nitrogen flow rate is adjusted to 60 L / min, the hydrogen flow rate is adjusted to 150 L / min, the ammonia flow rate is adjusted to 60 L / min, and the duration is 4 min;

[0178] The second stage: The graphite disk rotation speed is adjusted to 900 r / min, the reaction chamber temperature is adjusted to 950 °C, and the duration is 3 min;

[0179] At this time, the conditions of the MOCVD reaction chamber are: the reaction chamber temperature is 950 °C, the reaction chamber pressure is 500 torr, the nitrogen flow rate is 60 L / min, the hydrogen flow rate is 150 L / min, the ammonia flow rate is 60 L / min, and the graphite disk rotation speed is 900 r / min;

[0180] Under such conditions, a P-type GaN layer is grown on the P-type electron blocking layer; the P-type electron blocking layer is pGaN doped with Mg, and the doping concentration is 3×10 19 cm -3 , and the thickness of the P-type layer is 60 nm;

[0181] Step S8:

[0182] The MOCVD reaction chamber is adjusted from the conditions for growing the P-type electron blocking layer to a reaction chamber temperature of 25 °C through the following three stages:

[0183] The first stage: The reaction chamber temperature is adjusted to 750 °C, the reaction chamber pressure is adjusted to 200 torr, and the duration is 3 min;

[0184] The second stage: The nitrogen flow rate is adjusted to 120 L / min, the hydrogen flow rate is adjusted to 0 L / min, the ammonia flow rate is adjusted to 0 L / min, and the graphite disk rotation speed is adjusted to 700 r / min, and the duration is 3 min;

[0185] The third stage: The reaction chamber temperature is adjusted to 25 °C, and the graphite disk rotation speed is adjusted to 0 r / min for 10 min;

[0186] At this time, a GaN-based LED epitaxial wafer is obtained.

[0187] Comparative Example 1

[0188] Preparation of GaN-based LED epitaxial wafer:

[0189] The structural schematic diagram of the GaN-based LED epitaxial wafer is as Figure 1 shown. Specifically,

[0190] Step S1:

[0191] Provide a substrate Si and place the substrate on the graphite disk in the MOCVD reaction chamber;

[0192] Step S2:

[0193] Adjust the conditions of the MOCVD reaction chamber to the heat treatment conditions in one stage for 20 minutes:

[0194] At this time, the conditions of the MOCVD reaction chamber are: the temperature is 1150 °C, the reaction chamber pressure is 150 torr, the hydrogen flow rate is 250 L / min, and the graphite disk rotation speed is 1200 r / min

[0195] Perform heat treatment under these conditions for 5 minutes;

[0196] Step S3:

[0197] Adjust the MOCVD reaction chamber from the heat treatment conditions to the growth buffer layer conditions in one stage for 6 minutes:

[0198] At this time, the conditions of the MOCVD reaction chamber are: the reaction chamber temperature is 1150 °C, the reaction chamber pressure is 30 torr, the nitrogen flow rate is 15 L / min, the hydrogen flow rate is 250 L / min, the ammonia flow rate is 40 L / min, and the graphite disk rotation speed is 1200 r / min;

[0199] Grow a buffer layer of AlN and AlGaN on the heat-treated substrate under these conditions, with thicknesses of 200 nm and 900 nm respectively;

[0200] Step S4:

[0201] Adjust the MOCVD reaction chamber from the growth buffer layer conditions to the growth conditions of the unintentionally doped layer and the N-type GaN layer in one stage for 2 minutes;

[0202] At this time, the conditions of the MOCVD reaction chamber are: the reaction chamber temperature is 1000 °C, the reaction chamber pressure is 250 torr, the nitrogen flow rate is 100 L / min, the hydrogen flow rate is 200 L / min, the ammonia flow rate is 100 L / min, and the graphite disk rotation speed is 900 r / min;

[0203] Under this condition, an unintentionally doped layer and an N-type GaN layer are successively grown on the buffer layer. Among them, the thickness of the unintentionally doped layer is 1.5 μm, the thickness of the N-type GaN layer is 3.5 μm, the unintentionally doped layer is GaN, the N-type GaN layer is Si-doped GaN, and the doping concentration is 1×10 19 cm -3 ;

[0204] Step S5:

[0205] After a certain stage, the MOCVD reaction chamber is changed from the condition for growing the unintentionally doped layer and the N-type GaN layer to the condition for growing the multi-quantum well light-emitting layer, for 5 minutes:

[0206] At this time, the conditions of the MOCVD reaction chamber are: the reaction chamber temperature is 920 °C and 760 °C, which are the growth temperatures of the barrier and the well respectively, the reaction chamber pressure is 150 torr, the nitrogen flow rate is 120 L / min, the hydrogen flow rate is 0 L / min, the ammonia flow rate is 130 L / min, and the graphite disk rotation speed is 900 r / min;

[0207] Under this condition, a multi-quantum well light-emitting layer is grown on the N-type GaN layer. Among them, the structure of the multi-quantum well light-emitting layer is (Al x Ga 1-x N / In y Ga 1-y N) n where Al x Ga 1-x N is the barrier, the component x is 0.05, and the thickness is 5 nm; In y Ga 1-y N is the well, the component y is 0.16, and the thickness is 3 nm; the number of periods n is 6;

[0208] Step S6:

[0209] After a certain stage, the MOCVD reaction chamber is adjusted from the condition for growing the multi-quantum well light-emitting layer to the condition for growing the P-type electron blocking layer, for 3 minutes:

[0210] At this time, the conditions of the MOCVD reaction chamber are: the reaction chamber temperature is 1000 °C, the reaction chamber pressure is 200 torr, the nitrogen flow rate is 120 L / min, the hydrogen flow rate is 15 L / min, the ammonia flow rate is 30 L / min, and the graphite disk rotation speed is 1100 r / min;

[0211] Under this condition, a P-type electron blocking layer (EBL) is grown on the multi-quantum well light-emitting layer. Among them, the P-type electron blocking layer is Mg-doped pGaN, and the doping concentration is 3.5×10 19cm -3 The thickness of the P-type electron blocking layer is 50 nm;

[0212] Step S7:

[0213] After a stage, adjust the MOCVD reaction chamber from the conditions for growing the P-type electron blocking layer to the conditions for growing the P-type GaN layer, for 3 minutes:

[0214] At this time, the conditions of the MOCVD reaction chamber are: the reaction chamber temperature is 900 °C, the reaction chamber pressure is 300 torr, the nitrogen flow rate is 90 L / min, the hydrogen flow rate is 200 L / min, the ammonia flow rate is 100 L / min, and the rotation speed of the graphite disk is 1200 r / min;

[0215] Under these conditions, grow a P-type GaN layer on the P-type electron blocking layer; among them, the P-type electron blocking layer is pGaN doped with Mg, and the doping concentration is 3×10 19 cm -3 The thickness of the P-type layer is 80 nm;

[0216] Step S8:

[0217] After a stage, adjust the MOCVD reaction chamber from the conditions for growing the P-type electron blocking layer to a reaction chamber temperature of 25 °C, a reaction chamber pressure adjusted to 250 torr, and a nitrogen flow rate adjusted to 200 L / min, for 20 minutes;

[0218] At this time, a GaN-based LED epitaxial wafer is obtained.

[0219] <Test part>

[0220] Use a microscope to test the GaN-based LED epitaxial wafers obtained in Examples 1-2 and Comparative Example 1 to obtain their microscope photos, and the results are as Figures 2 to 4 shown.

[0221] Observe the microscope photos of the GaN-based LED epitaxial wafers obtained in Example 1, Example 2, and Comparative Example 1, Figure 2 and Figure 3 The surface of the GaN-based LED epitaxial wafer in has fewer particles, while Figure 4 The surface of the GaN-based LED epitaxial wafer in has more particles. The GaN-based LED epitaxial wafer with fewer surface particles has a higher surface quality. Therefore, compared with Comparative Example 1, the surface quality of the GaN-based LED epitaxial wafers obtained by controlling the MOCVD deposition conditions in Examples 1 and 2 is better.

[0222] In addition, Figure 1 There are almost no particles on the surface of the GaN-based LED epitaxial wafer in, while Figure 2There are a small number of particles on the surface of the GaN-based LED epitaxial wafer. Compared with Figure 2 , Figure 1 , the surface quality is better. That is, the surface quality of the GaN-based LED epitaxial wafer obtained in Example 1 is superior to that of the GaN-based LED epitaxial wafer obtained in Example 2, indicating that during the deposition process, by controlling the deposition conditions of each layer through multi-stage adjustment, the number of particles on the surface of the epitaxial wafer can be effectively reduced, and the surface quality of the epitaxial wafer can be improved.

[0223] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the principles of the present application shall be included within the protection scope of the present application.

Claims

1. A method for preparing a GaN-based LED epitaxial wafer, characterized in that, It includes the following steps: Step S1: Provide a substrate and place the substrate on a graphite disk in an MOCVD reaction chamber; Step S2: Perform heat treatment on the substrate. The conditions for the heat treatment include: the temperature of the heat treatment is 1000 - 1100 °C, the pressure in the reaction chamber is 80 - 120 torr, the hydrogen flow rate is 150 - 200 L / min, the rotation speed of the graphite disk is 900 - 1100 r / min, and the treatment time is 1 - 3 min; Step S3: Grow a buffer layer on the heat-treated substrate. The conditions for growing the buffer layer include: the temperature of the reaction chamber is 800 - 1050 °C, the pressure in the reaction chamber is 50 - 100 torr, the nitrogen flow rate is 0 - 10 L / min, the hydrogen flow rate is 150 - 200 L / min, the ammonia flow rate is 5 - 30 L / min, the rotation speed of the graphite disk is 900 - 1100 r / min, and the growth thickness is 300 - 1000 nm; Step S4: Sequentially grow an unintentionally doped layer and an N-type GaN layer on the buffer layer. The thickness of the unintentionally doped layer is 0.5 - 1 μm, and the thickness of the N-type GaN layer is 2 - 3 μm. The conditions for growing the unintentionally doped layer and the N-type GaN layer include: the temperature of the reaction chamber is 1050 - 1200 °C, the pressure in the reaction chamber is 150 - 200 torr, the nitrogen flow rate is 60 - 80 L / min, the hydrogen flow rate is 100 - 150 L / min, the ammonia flow rate is 40 - 80 L / min, and the rotation speed of the graphite disk is 1000 - 1200 r / min; Step S5: Grow a multi-quantum well light-emitting layer on the N-type GaN layer. The conditions for growing the multi-quantum well light-emitting layer include: the temperature of the reaction chamber is 750 - 900 °C, the pressure in the reaction chamber is 200 - 300 torr, the nitrogen flow rate is 90 - 110 L / min, the hydrogen flow rate is 0 - 5 L / min, the ammonia flow rate is 80 - 120 L / min, and the rotation speed of the graphite disk is 1000 - 1200 r / min; Step S6: Grow a P-type electron blocking layer on the multi-quantum well light-emitting layer. The conditions for growing the P-type electron blocking layer include: the temperature of the reaction chamber is 850 - 950 °C, the pressure in the reaction chamber is 100 - 150 torr, the nitrogen flow rate is 80 - 100 L / min, the hydrogen flow rate is 0 - 10 L / min, the ammonia flow rate is 10 - 20 L / min, and the rotation speed of the graphite disk is 800 - 1000 r / min; Step S7: Grow a P-type GaN layer on the P-type electron blocking layer. The conditions for growing the P-type GaN layer include: the temperature of the reaction chamber is 950 - 1050 °C, the pressure in the reaction chamber is 400 - 600 torr, the nitrogen flow rate is 60 - 80 L / min, the hydrogen flow rate is 150 - 180 L / min, the ammonia flow rate is 60 - 80 L / min, and the rotation speed of the graphite disk is 900 - 1100 r / min; Step S8: After growing the P-type GaN layer, adjust the temperature of the reaction chamber to 20 - 30 °C to obtain a GaN-based LED epitaxial wafer.

2. The method according to claim 1, characterized in that, In the step S2, before the heat treatment, it includes: adjusting to the conditions of the heat treatment through the first stage to the fifth stage in sequence, where, The first stage includes: adjusting the reaction chamber pressure to 20 - 30 torr, the nitrogen flow rate to 10 - 20 L / min, increasing the rotation speed of the graphite disk to 100 - 200 r / min, and the duration is 1 - 2 min; The second stage includes: adjusting the reaction chamber pressure to 80 - 120 torr, the nitrogen flow rate to 0 L / min, the hydrogen flow rate to 70 - 100 L / min, and the duration is 1 - 2 min; The third stage includes: adjusting the nitrogen flow rate to 50 - 70 L / min, the hydrogen flow rate to 100 - 150 L / min, the rotation speed of the graphite disk to 500 - 700 r / min, and the duration is 1 - 2 min; The fourth stage includes: adjusting the reaction chamber temperature to 500 - 600 °C, the rotation speed of the graphite disk to 900 - 1100 r / min, and the duration is 5 - 7 min; The fifth stage includes: adjusting the reaction chamber temperature to 1000 - 1100 °C, the nitrogen to 0 L / min, the hydrogen to 150 - 200 L / min, the rotation speed of the graphite disk to 900 - 1000 r / min, and the duration is 7 - 10 min.

3. The method according to claim 1, characterized in that, In the step S3, before the growth of the buffer layer, it includes: adjusting from the conditions of the heat treatment to the conditions of the growth of the buffer layer through the first stage to the third stage in sequence, where, The first stage includes: adjusting the reaction chamber pressure to 50 - 100 torr, the nitrogen flow rate to 0 - 10 L / min, and the duration is 1 - 2 min; The second stage includes: adjusting the hydrogen flow rate to 150 - 200 L / min, the ammonia flow rate to 5 - 30 L / min, and the duration is 1 - 2 min; The third stage includes: adjusting the rotation speed of the graphite disk to 900 - 1100 r / min, the reaction chamber temperature to 800 - 1050 °C, and the duration is 1 - 2 min.

4. The method according to claim 1, wherein In the step S4, before the growth of the unintentionally doped layer and the N-type GaN layer, it includes: adjusting from the conditions of the growth of the buffer layer to the conditions of the growth of the unintentionally doped layer and the N-type GaN layer through the first stage to the third stage in sequence, where, The first stage includes: adjusting the reaction chamber pressure to 150 - 200 torr, the nitrogen flow rate to 60 - 80 L / min, and the duration is 2 - 3 min; The second stage includes: adjusting the hydrogen flow rate to 100 - 150 L / min, the ammonia flow rate to 40 - 80 L / min, and the duration is 2 - 3 min; The third stage includes: adjusting the rotation speed of the graphite disk to 1000 - 1200 r / min, the reaction chamber temperature to 1050 - 1200 °C, and the duration is 3 - 4 min.

5. The method according to claim 1, characterized in that, In step S5, before growing the multi-quantum well light-emitting layer, the following steps are included: successively passing through the first stage to the third stage to reach the conditions for growing the multi-quantum well light-emitting layer from the conditions for growing the unintentionally doped layer and the N-type GaN layer, where The first stage includes: adjusting the reaction chamber pressure to 200 - 300 torr, adjusting the nitrogen flow rate to 90 - 110 L / min, and the duration is 2 - 3 min; The second stage includes: adjusting the hydrogen flow rate to 0 - 5 L / min, adjusting the ammonia flow rate to 80 - 120 L / min, and the duration is 3 - 4 min; The third stage includes: adjusting the graphite disk rotation speed to 1000 - 1200 r / min, adjusting the reaction chamber temperature to 750 - 900 °C, and the duration is 3 - 4 min.

6. The method according to claim 1, characterized in that, The structure of the multi-quantum well light-emitting layer is (Al x Ga 1-x N / In y Ga 1-y N) n , where Al x Ga 1-x N serves as the barrier, the composition x can range from 0 to 0.4, and the thickness is 3 to 5 nm; In y Ga 1-y N is a potential well, the component y can be between 0 and 0.3, and the thickness is 2 to 4 nm; The number of cycles n is 3 - 6.

7. The method according to claim 1, wherein In step S6, before growing the P-type electron blocking layer, the following steps are included: successively passing through the first stage to the third stage to adjust from the conditions for growing the multi-quantum well light-emitting layer to the conditions for growing the P-type electron blocking layer, where The first stage includes: adjusting the reaction chamber pressure to 100 - 150 torr, adjusting the nitrogen flow rate to 80 - 100 L / min, and the duration is 2 - 3 min; The second stage includes: adjusting the hydrogen flow rate to 0 - 10 L / min, adjusting the ammonia flow rate to 10 - 20 L / min, and the duration is 3 - 4 min; The third stage includes: adjusting the graphite disk rotation speed to 800 - 1000 r / min, adjusting the reaction chamber temperature to 850 - 950 °C, and the duration is 2 - 3 min.

8. The method according to claim 1, characterized in that, In step S7, before growing the P-type GaN layer, the following steps are included: successively passing through the first stage to the third stage to adjust from the conditions for growing the P-type electron blocking layer to the conditions for growing the P-type GaN layer, where The first stage includes: adjusting the reaction chamber pressure to 400 - 600 torr, adjusting the nitrogen flow rate to 60 - 80 L / min, and the duration is 3 - 4 min; The second stage includes: adjusting the hydrogen flow rate to 150 - 180 L / min, adjusting the ammonia flow rate to 60 - 80 L / min, and the duration is 3 - 4 min; The third stage includes: adjusting the graphite disk rotation speed to 900 - 1100 r / min, adjusting the reaction chamber temperature to 950 - 1050 °C, and the duration is 2 - 3 min.

9. The method according to any one of claims 1 to 8, characterized in that After growing the P-type GaN layer, adjusting the reaction chamber temperature to 20 - 30 °C includes: successively passing through the first stage to the sixth stage to adjust from the conditions for growing the P-type electron blocking layer to the reaction chamber temperature of 20 - 30 °C, where The first stage includes: adjusting the reaction chamber pressure to 150 - 200 torr, and the duration is 2 - 3 min; The second stage includes: adjusting the nitrogen flow rate to 120 - 150 L / min, adjusting the hydrogen flow rate to 0 L / min, adjusting the ammonia flow rate to 0 L / min, and the duration is 3 - 4 min; The third stage includes: adjusting the graphite disk rotation speed to 600 - 700 r / min, and the duration is 2 - 3 min; The fourth stage includes: adjusting the temperature of the reaction chamber to 700 - 800 °C, with a duration of 2 - 3 min; The fifth stage includes: adjusting the temperature of the reaction chamber to 400 - 500 °C, with a duration of 5 - 10 min; The sixth stage includes: adjusting the temperature of the reaction chamber to 20 - 30 °C, for 5 - 10 min.

10. A GaN-based LED epitaxial wafer, characterized in that, Prepared by the method according to any one of claims 1 - 9.

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