Red light LED device based on diffusion of In atoms into multiple quantum wells and preparation method thereof

Abstract

The present invention discloses a red light LED based on the diffusion of In atoms into multiple quantum wells and a preparation method thereof, which mainly solves the problems of the existing red light LEDs such as the difficulty in growing InGaN with high In content, serious In atom segregation, and significant quantum confinement Stark effect, which lead to low efficiency of the light-emitting diode. The invention comprises, from bottom to top, a c-plane sapphire substrate layer (1), an AlN nucleation layer (2), an n-type GaN layer (3), an In x Ga 1‑x N / GaN multi-quantum well (4), an electron blocking layer (6) and a p-type layer (7), a positive electrode (8) is provided on the p-type layer, a negative electrode (9) is provided on the n-type GaN layer, a metal In layer (5) is sputtered between the multi-quantum well and the electron blocking layer, and the In component in the multi-quantum well layer is increased through thermal diffusion, and the emission wavelength is lengthened. The invention improves the efficiency of the light-emitting diode, can be used to manufacture a high-efficiency red light emitting device, and realizes full-color display of nitride.

Description

Technical Field

[0001] The invention belongs to the field of microelectronic technology, and particularly relates to a red light emitting diode, which can be used to manufacture a high-efficiency red light emitting device and realize full-color display of nitride. Technical Background

[0002] Currently, red LEDs are mostly made of phosphides. Compared with phosphides, nitrides are harmless, and InGaN-based blue and green LEDs have been commercially mass-produced. If high-efficiency red LEDs can be achieved, full-color display of nitrides can be achieved.

[0003] The efficiency of InGaN-based long-wavelength LEDs decreases rapidly with the increase of In atomic components. Since InN has a low dissociation temperature, InGaN must be grown at low temperature. The defects introduced by this will reduce the luminous efficiency of the LED. At the same time, the increase in In components increases the strain, intensifies the segregation of In atoms, and makes the quantum-confined Stark effect more significant, further reducing the luminous efficiency of red LEDs.

[0004] The patent document with application number 202110219749.5 proposes a method for preparing an InGaN-based red light LED chip structure, including: this preparation method provides a sapphire substrate with an epitaxial surface orientation of a c-plane and a certain bevel angle, the bevel angle is greater than 0.2°, a buffer layer is deposited thereon, and then an LED epitaxial structure is grown, the well layer of the light-emitting layer in the LED epitaxial structure is an InGaN layer, and the band gap of the InGaN layer is made to be 1.6-2eV by controlling the In content in the InGaN layer. This invention can effectively increase the atomic step density of the epitaxial surface, reduce the step terrace width, and promote the entry of In atoms in the InGaN layer, but since a sapphire substrate with a bevel angle greater than 0.2° is required, it brings considerable difficulties to the preparation of the substrate.

[0005] Patent document No. 202010806206.9 proposes a method for preparing an InGaN / GaN multi-quantum well-based red light LED structure, the structure of which is as follows: Figure 1 From bottom to top, it includes: sapphire substrate 1, low-temperature GaN buffer layer 2, undoped GaN layer 3, n-type GaN layer 4, InGaN / GaN superlattice stress release layer 5, InGaN / GaN multi-quantum well active region 6, p-type AlGaN electron blocking layer 7, p-type GaN layer 8, p-type InGaN ohmic contact layer 9. Although the device can achieve a longer red light, the external quantum efficiency of the red LED is low, and the manufacturing difficulty is increased because the superlattice stress release layer 5 needs to be grown under the multi-quantum well. Summary of the invention

[0006] The purpose of the present invention is to address the above-mentioned deficiencies and propose a red light LED device based on the diffusion of In atoms into multiple quantum wells and a preparation method thereof, so as to simplify the device structure and improve the luminous efficiency of the red light LED while ensuring the luminous wavelength.

[0007] The technical idea of ​​the present invention is: based on the green light LED, a metal In layer is sputtered on the multi-quantum well layer, and In atoms are diffused into the In by thermal diffusion. x Ga 1-x In N / GaN multi-quantum wells, increasing the In component in the multi-quantum wells can increase the emission wavelength and improve the luminous efficiency of red LEDs. The implementation scheme is as follows:

[0008] 1. A red light LED device based on the diffusion of In atoms into a multi-quantum well, comprising, from bottom to top: a c-plane sapphire substrate layer (1), an AlN nucleation layer (2), an n-type GaN layer (3), an In x Ga 1-x An N / GaN multi-quantum well (4), an electron blocking layer (6) and a p-type layer (7), wherein a positive electrode (8) is provided on the p-type layer (7), and a negative electrode (9) is provided on the n-type GaN layer (3), characterized in that a metal In layer (5) is provided between the multi-quantum well (4) and the electron blocking layer (6) to increase the In component in the multi-quantum well layer (4), increase the emission wavelength of the device, and improve the luminous efficiency of the red light LED.

[0009] Furthermore, the thickness of the AlN nucleation layer (2) is 20nm-50nm;

[0010] Furthermore, the thickness of the n-type GaN layer (3) is 1000nm-1200nm;

[0011] Furthermore, the thickness of the metal In layer (5) is 8nm-12nm.

[0012] Furthermore, the thickness of the electron blocking layer (6) is 25-35 nm;

[0013] Furthermore, the thickness of the p-type GaN layer (7) is 100-300 nm.

[0014] Further, the In x Ga 1-x The thickness of the N / GaN multi-quantum well (4) is 300-480 nm, and the adjustment range of the In content x is 0.1-0.3.

[0015] 2. A red light LED based on diffusion of In atoms into multiple quantum wells and a preparation method thereof, characterized in that it comprises the following steps:

[0016] 1) Heat-treat the sapphire substrate, clean the c-plane sapphire substrate, place it in the MOCVD reaction chamber, and reduce the vacuum degree of the reaction chamber to less than 2×10 -2 Torr; then introduce hydrogen into the reaction chamber, and heat the substrate to 900-1200°C and maintain it for 5-10 minutes under the condition that the pressure of the MOCVD reaction chamber reaches 20-760 Torr. Place the heat-treated substrate in a reaction chamber at a temperature of 1000-1100°C, introduce ammonia at a flow rate of 3000-4000 sccm, and continue nitriding for 3-5 minutes;

[0017] 2) growing a high-temperature AlN nucleation layer with a thickness of 20-50 nm on the nitrided substrate using a MOCVD process;

[0018] 3) growing an n-type GaN layer with a thickness of 1000-1200 nm on the AlN nucleation layer using a MOCVD process;

[0019] 4) Six cycles of In are grown on the n-type GaN layer using MOCVD x Ga 1-x N / GaN quantum well, single layer In per period x Ga 1-x The thicknesses of the N well layer and the GaN barrier layer are 20-40nm and 60-80nm respectively, and the In content x is adjusted in the range of 0.1-0.3;

[0020] 5) In x Ga 1-x A metal In layer with a thickness of 10 nm is deposited on the N / GaN multi-quantum well structure by sputtering metal, and then the temperature of the reaction chamber is maintained at 600-800°C, and the sample is heat-treated to allow In atoms to diffuse into the multi-quantum well layer;

[0021] 6) Using MOCVD process to grow Al with a thickness of 30nm on the metal In layer y Ga 1-y N electron blocking layer, the adjustment range of y is 0.7-1;

[0022] 7) In Al y Ga 1-y A p-type GaN layer with a thickness of 100-300 nm is grown on the N electron blocking layer, and then the reaction chamber temperature is maintained at 800-1000°C and annealed for 5-10 minutes in a H2 atmosphere;

[0023] 8) Adopting the metal sputtering method to deposit an n-type electrode on the n-type GaN layer and a p-type electrode on the p-type GaN layer, respectively, to complete the production of the light-emitting diode.

[0024] Compared with the traditional method for preparing LED, the present invention has the following advantages:

[0025] In the present invention, a metal In layer is added between the multi-quantum well and the electron blocking layer, so that In atoms can enter the In x Ga 1-x In N / GaN multi-quantum wells, the stress on the multi-quantum wells during the growth process is reduced, which greatly alleviates the quantum confinement Stark effect and weakens the segregation problem of In atoms, greatly improving the luminescence efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the existing red LED structure diagram;

[0027] Figure 2 This is a structural diagram of a red light LED based on the diffusion of In atoms into multiple quantum wells of the present invention;

[0028] Figure 3 The invention is made Figure 2 Schematic diagram of the diode flow chart. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0030] Reference Figure 2 The device structure of the present invention comprises: a c-plane sapphire substrate layer 1, a high-temperature AlN nucleation layer 2, an n-type GaN layer 3, an In x Ga 1-x N / GaN multi-quantum well 4, metal In layer 5, electron blocking layer 6, p-type layer 7 and electrode 8. The high-temperature AlN nucleation layer 2 is located on the c-plane sapphire substrate layer 1, and its thickness is 20-50nm; the n-type GaN layer 3 is located on the high-temperature AlN nucleation layer 2, and its thickness is 1000-1200nm; the In x Ga 1-x The N / GaN multi-quantum well structure 4 is located on the n-type GaN layer 3, with a total of six periods and a total thickness of 300-480nm. The parameter x of the In content is adjusted in the range of 0.1-0.5. Quantum wells with different In contents can prepare LEDs with different luminous wavelengths. The metal In layer 5 is located on the In x Ga 1-x The N / GaN multi-quantum well structure 4 has a thickness of 8-12nm; the electron blocking layer 6 is located on the metal In layer 5, and has a thickness of 25-35nm; the p-type GaN layer 7 is located on the electron blocking layer 6, and has a thickness of 100-300nm; the electrode 8 includes an n-type electrode and a p-type electrode, which are respectively located on the n-type GaN layer 3 and the p-type layer 7.

[0031] Reference Figure 3The present invention provides three embodiments for preparing red light LEDs based on the diffusion of In atoms into multiple quantum wells.

[0032] Example 1: Prepare a red light LED with a light emission wavelength of 630 nm.

[0033] Step 1: pre-treat the substrate.

[0034] 1a) After cleaning, the c-plane sapphire substrate is placed in a metal organic chemical vapor deposition (MOCVD) reaction chamber and the vacuum degree of the reaction chamber is reduced to 2×10 -2 Torr; hydrogen is introduced into the reaction chamber, and when the pressure of the MOCVD reaction chamber reaches 20 Torr, the substrate is heated to 900°C and maintained for 10 minutes to complete the heat treatment of the substrate;

[0035] 1b) placing the heat-treated substrate in a reaction chamber at a temperature of 1000° C., introducing ammonia gas at a flow rate of 3500 sccm for 5 minutes to perform nitridation, thereby completing nitridation.

[0036] Step 2: Using MOCVD process to grow high temperature AlN layer, such as Figure 3 (a).

[0037] The temperature of the reaction chamber was adjusted to 950° C., and ammonia gas with a flow rate of 3000 sccm and an aluminum source with a flow rate of 40 sccm were introduced at the same time. While maintaining the pressure at 20 Torr, a high-temperature AlN nucleation layer with a thickness of 20 nm was grown on the nitrided substrate.

[0038] Step 3: grow n-type GaN layer by MOCVD process, such as Figure 3 (b).

[0039] The temperature of the reaction chamber was adjusted to 950°C, and three gases, namely, ammonia with a flow rate of 2500sccm, gallium source with a flow rate of 150sccm and silicon source with a flow rate of 10sccm, were introduced at the same time. While maintaining the pressure at 20Torr, a 1000nm thick n-type GaN layer was grown on the AlN nucleation layer.

[0040] Step 4: Using MOCVD process to grow In 0.15 Ga 0.85 N / GaN multi-quantum well structure, such as Figure 3 (c).

[0041] The reaction chamber temperature was adjusted to 700°C, the pressure was maintained at 20 Torr, and a nitrogen source with a flow rate of 1000 sccm and a gallium source with a flow rate of 80 sccm were introduced at the same time. Six periods of In were grown on the n-type GaN layer using the MOCVD method. 0.15 Ga 0.85N / GaN quantum well, where In is grown 0.15 Ga 0.85 The indium source flow rate is maintained at 160 sccm for the N-well layer.

[0042] Step 5: deposit a metal In layer, such as Figure 3 (d).

[0043] A metal In layer with a thickness of 8 nm was deposited on the multi-quantum well by sputtering metal. The temperature of the reaction chamber was then maintained at 600°C and the sample was heat treated to allow In atoms to diffuse into the multi-quantum well layer.

[0044] Step 6: Using MOCVD process to grow Al 0.65 Ga 0.35 N electron blocking layer, such as Figure 3 (e).

[0045] The temperature of the reaction chamber was adjusted to 780°C, the pressure was maintained at 20 Torr, and a nitrogen source with a flow rate of 1000 sccm, a gallium source with a flow rate of 40 sccm, and an aluminum source with a flow rate of 200 sccm were introduced at the same time. Al with a thickness of 25 nm was grown on the metal In layer by MOCVD. 0.65 Ga 0.35 N electron blocking layer.

[0046] Step 7: grow a p-type layer using MOCVD process, such as Figure 3 (f).

[0047] The temperature of the reaction chamber was adjusted to 950°C, and ammonia with a flow rate of 2500sccm, a gallium source with a flow rate of 150sccm, and a magnesium source with a flow rate of 100sccm were introduced at the same time. The pressure was maintained at 20Torr, and the MOCVD method was used to generate Al 0.65 Ga 0.35 A p-type GaN layer with a thickness of 100 nm is grown on the N electron blocking layer; then the temperature of the reaction chamber is maintained at 800° C. and annealed for 10 minutes in a H 2 atmosphere.

[0048] Step eight, depositing electrodes, such as Figure 3 (g)

[0049] The metal sputtering method is used to deposit an n-type electrode at a position on the n-type GaN layer where no other layers are grown, and a p-type electrode is deposited on the p-type layer to complete the production of the red light LED device.

[0050] Example 2: Prepare a red light LED with a light emission wavelength of 640 nm.

[0051] Step 1: pre-treat the substrate.

[0052] The specific implementation of this step is the same as step 1 of Example 1.

[0053] Step 2: grow a high temperature AlN layer using MOCVD process, such as Figure 3 (a).

[0054] A high-temperature AlN nucleation layer with a thickness of 35 nm was grown on the pretreated c-plane sapphire substrate using the MOCVD process. The process conditions are:

[0055] The temperature of the reaction chamber was set at 1050° C., and two gases, ammonia with a flow rate of 3500 sccm and aluminum source with a flow rate of 30 sccm, were introduced at the same time, and the pressure was maintained at 40 Torr.

[0056] Step 3, using MOCVD process to grow n-type GaN layer, such as Figure 3 (b).

[0057] An n-type GaN layer with a thickness of 1100 nm is grown on the AlN nucleation layer by MOCVD. The process conditions are:

[0058] The temperature of the reaction chamber was set at 1050° C., and three gases, namely, ammonia with a flow rate of 2800 sccm, gallium source with a flow rate of 160 sccm, and silicon source with a flow rate of 15 sccm, were introduced at the same time, and the pressure was maintained at 40 Torr.

[0059] Step 4: grow In using MOCVD process 0.16 Ga 0.84 N / GaN multi-quantum well structure, such as Figure 3 (c).

[0060] Six periods of In were grown on the n-type GaN layer using MOCVD. 0.16 Ga 0.84 N / GaN quantum well, its process conditions are:

[0061] The reaction chamber temperature is 800°C, the pressure is 40 Torr, the nitrogen source flow rate is 1100 sccm, the gallium source flow rate is 60 sccm, and the In growth 0.16 Ga 0.82 The indium source flow rate for the N-well layer is 180 sccm.

[0062] Step 5, depositing a metal In layer, such as Figure 3 (d).

[0063] A metal In layer with a thickness of 10 nm was deposited on the multi-quantum well by sputtering metal. The temperature of the reaction chamber was then maintained at 700°C and the sample was heat treated to allow In atoms to diffuse into the multi-quantum well layer.

[0064] Step 6: Grow Al using MOCVD process 0.7 Ga0.3 N electron blocking layer, such as Figure 3 (e).

[0065] The Al layer with a thickness of 30 nm is grown on the metal In layer by MOCVD. 0.7 Ga 0.3 N layer, its process conditions are:

[0066] The reaction chamber temperature is 760° C., the pressure is 25 Torr, the flow rate of the nitrogen source is 1100 sccm, the flow rate of the gallium source is 60 sccm, and the flow rate of the aluminum source is 205 sccm.

[0067] Step 7, using MOCVD process to grow p-type layer, such as Figure 3 (f).

[0068] In Al 0.7 Ga 0.3 A 200nm thick GaN layer was grown on the N electron blocking layer by MOCVD. The process conditions were as follows: the reaction chamber temperature was 1050°C, ammonia gas with a flow rate of 2800sccm, gallium source gas with a flow rate of 200sccm, and magnesium source gas were introduced simultaneously, and the pressure was 40Torr.

[0069] Afterwards, the temperature of the reaction chamber was maintained at 900° C. and annealing was performed for 8 min in a H 2 atmosphere.

[0070] Step 8, depositing electrodes, such as Figure 3 (g)

[0071] The specific implementation of this step is the same as step eight of Example 1, and the preparation of a red light LED with a light emission wavelength of 640 nm is completed.

[0072] Example 3: Prepare a red light diode with a light emission wavelength of 650nm.

[0073] Step A: pre-treating the substrate.

[0074] The specific implementation of this step is the same as step 1 of Example 1.

[0075] Step B: growing a high temperature AlN layer using a MOCVD process.

[0076] The reaction chamber temperature was set to 1100°C, and ammonia gas with a flow rate of 4000 sccm and aluminum source with a flow rate of 20 sccm were introduced at the same time. The process condition of the pressure was maintained at 60 Torr, and a high-temperature AlN nucleation layer with a thickness of 50 nm was grown on the pretreated substrate. Figure 3 (a).

[0077] Step C: growing an n-type GaN layer using a MOCVD process.

[0078] The reaction chamber temperature was maintained at 1100°C, the pressure was maintained at 60 Torr, the ammonia flow rate was 3000 sccm, the gallium source flow rate was 180 sccm, and the silicon source flow rate was 20 sccm, and an n-type GaN layer with a thickness of 1200 nm was grown on the AlN nucleation layer. Figure 3 (b).

[0079] Step D, growing In using MOCVD process 0.18 Ga 0.82 N / GaN multiple quantum well structure.

[0080] The process conditions were set at 900°C, 60 Torr, 1200 sccm of nitrogen source flow, and 40 sccm of gallium source flow to grow six cycles of In on the n-type GaN layer. 0.18 Ga 0.82 N / GaN quantum well, where In is grown 0.18 Ga 0.82 When the N-well layer is used, the indium source flow rate is maintained at 200 sccm. Figure 3 (c).

[0081] Step E: depositing a metal In layer.

[0082] A metal In layer with a thickness of 12 nm was deposited on the multi-quantum well by sputtering metal. The temperature of the reaction chamber was then maintained at 800 °C and the sample was heat treated to allow In atoms to diffuse into the multi-quantum well layer. Figure 3 (d).

[0083] Step F, growing Al by MOCVD process 0.75 Ga 0.25 N electron blocking layer.

[0084] Under the process conditions of setting the reaction chamber temperature to 920°C, the pressure to 30 Torr, the nitrogen source flow rate to 1200 sccm, the gallium source flow rate to 80 sccm, and the aluminum source flow rate to 210 sccm, a 35 nm thick Al layer was grown on the metal In layer. 0.75 Ga 0.25 N layers, such as Figure 3 (e).

[0085] Step G: growing a p-type layer by using MOCVD process.

[0086] The process conditions were set as follows: the reaction chamber temperature was 1100°C, the pressure was 60 Torr, the flow rate of the nitrogen source was 3000 sccm, the flow rate of the gallium source was 180 sccm, and the flow rate of the magnesium source was 300 sccm. 0.75 Ga 0.25A p-type GaN layer with a thickness of 300 nm is grown on the N electron blocking layer; then the reaction chamber temperature is maintained at 1000°C and annealed for 5 min in a H2 atmosphere. Figure 3 (f).

[0087] Step H, depositing electrodes.

[0088] The specific implementation of this step is the same as step eight of Example 1, and the preparation of a red light LED with a light emission wavelength of 650 nm is completed. Figure 3 (g).

[0089] The above descriptions are only three specific examples of the present invention and do not constitute any limitation to the present invention. Obviously, for professionals in this field, after understanding the content and principles of the present invention, it is possible to make various modifications and changes in form and details without departing from the principles and structures of the present invention. However, these modifications and changes based on the ideas of the present invention are still within the scope of protection of the claims of the present invention.

Claims

1. A red LED device based on the diffusion of In atoms into multiple quantum wells, comprising from bottom to top: c-plane sapphire substrate layer (1), AlN nucleation layer (2), n-type GaN layer (3), In x Ga 1-x An N / GaN multi-quantum well (4), an electron blocking layer (6) and a p-type layer (7), wherein a positive electrode (8) is provided on the p-type layer (7), and a negative electrode (9) is provided on the n-type GaN layer (3), characterized in that a metal In layer (5) is provided between the multi-quantum well (4) and the electron blocking layer (6) to increase the In component in the multi-quantum well layer (4), increase the emission wavelength of the device, and improve the luminous efficiency of the red light LED.

2. The device according to claim 1, characterized in that: The thickness of the AlN nucleation layer (2) is 20nm-50nm; The thickness of the n-type GaN layer (3) is 1000nm-1200nm; The thickness of the metal In layer (5) is 8nm-12nm; The thickness of the electron blocking layer (6) is 25-35 nm; The thickness of the p-type layer (7) is 100-300 nm.

3. The device according to claim 1, characterized in that: In x Ga 1-x The thickness of the N / GaN multi-quantum well (4) is 300-480nm, and the adjustment range of the In content x is 0.15-0.

18.

4. A red light LED based on diffusion of In atoms into multiple quantum wells and a preparation method thereof, characterized in that: The steps include: 1) heat-treating the sapphire substrate, and then placing the heat-treated substrate in a reaction chamber at a temperature of 1000-1100° C., introducing ammonia gas at a flow rate of 3000-4000 sccm for 3-5 minutes for nitridation; 2) growing a high-temperature AlN nucleation layer with a thickness of 20-50 nm on the nitrided substrate using a MOCVD process; 3) growing an n-type GaN layer with a thickness of 1000-1200 nm on the AlN nucleation layer using a MOCVD process; 4) Six cycles of In are grown on the n-type GaN layer using MOCVD x Ga 1-x N / GaN quantum well, single layer In per period x Ga 1-x The thicknesses of the N well layer and the GaN barrier layer are 20-40nm and 60-80nm respectively, and the In content x is adjusted in the range of 0.15-0.18; 5) In x Ga 1-x A metal In layer with a thickness of 10 nm is deposited on the N / GaN multi-quantum well structure by sputtering metal, and then the temperature of the reaction chamber is maintained at 600-800°C, and the sample is heat-treated to allow In atoms to diffuse into the multi-quantum well layer; 6) Using MOCVD process to grow Al with a thickness of 30nm on the metal In layer y Ga 1-y N electron blocking layer, The adjustment range of y is 0.65-0.75; 7) In Al y Ga 1-y A p-type GaN layer with a thickness of 100-300 nm is grown on the N electron blocking layer, and then the reaction chamber temperature is maintained at 800-1000°C and annealed for 5-10 minutes in a H2 atmosphere; 8) Using a metal sputtering method, an n-type electrode is deposited on the n-type GaN layer, and a p-type electrode is deposited on the p-type GaN layer, respectively, to complete the production of the light-emitting diode.

5. The method according to claim 4, characterized in that In step 1), the substrate is heat treated. First, the c-plane sapphire substrate is cleaned and placed in the MOCVD reaction chamber, and the vacuum degree of the reaction chamber is reduced to less than 2×10 -2 Torr; then hydrogen is introduced into the reaction chamber, and under the condition that the pressure of the MOCVD reaction chamber reaches 20-760 Torr, the substrate is heated to a temperature of 900-1200°C and maintained for 5-10 minutes.

6. The method according to claim 4, characterized in that The MOCVD process used in step 2) is to set the following condition parameters for the reaction chamber: The reaction chamber temperature is 950-1100°C. Maintain the reaction chamber pressure at 20-60 Torr, Two gases, ammonia gas with a flow rate of 3000-4000 sccm and aluminum source gas with a flow rate of 20-40 sccm, are introduced into the reaction chamber at the same time.

7. The method according to claim 4, characterized in that The MOCVD process used in step 3) is to set the following condition parameters for the reaction chamber: The reaction chamber temperature is 950-1100°C. Maintain the reaction chamber pressure at 20-60 Torr, Three gases, namely, ammonia gas with a flow rate of 2500-3000 sccm, gallium source gas with a flow rate of 150-180 sccm, and silicon source gas with a flow rate of 10-20 sccm, are introduced into the reaction chamber at the same time.

8. The method according to claim 4, characterized in that The MOCVD process used in step 4) is to set the following condition parameters for the reaction chamber: The reaction chamber temperature is 700-900°C. Maintain the reaction chamber pressure at 20-60 Torr, Three gases, namely, a nitrogen source with a flow rate of 1000-1200 sccm, a gallium source with a flow rate of 40-80 sccm, and an indium source with a flow rate of 160-200 sccm, are introduced into the reaction chamber at the same time.

9. The method according to claim 4, characterized in that The MOCVD process used in step 6) is to set the following condition parameters for the reaction chamber: The reaction chamber temperature is 780-920°C, Maintain the reaction chamber pressure at 20-30 Torr, Three gases, namely, a nitrogen source with a flow rate of 1000-1200 sccm, a gallium source with a flow rate of 40-80 sccm, and an aluminum source with a flow rate of 200-210 sccm, are introduced into the reaction chamber at the same time.

10. The method according to claim 4, characterized in that The MOCVD process used in step 7) is to set the following condition parameters for the reaction chamber: The reaction chamber temperature is 950-1100°C. Maintain the reaction chamber pressure at 20-60 Torr, Three gases, namely, ammonia gas with a flow rate of 2500-3000 sccm, gallium source gas with a flow rate of 150-180 sccm, and magnesium source gas with a flow rate of 100-300 sccm, are introduced into the reaction chamber at the same time.

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