A GaN-based epitaxial layer growth method for improving light emitting efficiency of LED chips

Abstract

The application relates to the technical field of LED chip, in particular to a GaN-based epitaxial layer growth method for improving the light-emitting efficiency of an LED chip. The GaN-based epitaxial layer growth method for improving the light-emitting efficiency of an LED chip comprises the following steps: S2: setting the reaction cavity temperature, pressure, and introducing ammonia, nitrogen, 100-300 sccm of TMGa2, 400-600 sccm of TMIn and 25-200 sccm of TMAl, and continuously maintaining for 5-20 seconds; making a 0.01-0.03 um doped buffer layer grow on the substrate; S3: making a 0.1-0.15 um undoped buffer layer grow on the doped buffer layer; and S9: completing the growth of the GaN-based epitaxial layer. The GaN-based epitaxial layer has the beneficial effects that the buffer layer of the GaN-based epitaxial layer comprises a high-doped-concentration doped buffer layer (the doped element is TMIN and AL) and an undoped buffer layer, the structure improves the epitaxial stress of the epitaxial layer, thins the buffer layer, and improves the light-emitting efficiency of the LED chip; and the brightness of the GaN-based epitaxial layer is improved by 2%-5% compared with the brightness of a conventional LED structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of LED chip, and particularly relates to a GaN-based epitaxial layer growth method for improving the light-emitting efficiency of an LED chip. BACKGROUND

[0002] As a new type of solid-state lighting source, GaN-based light-emitting diode (LED) is high-efficient, environment-friendly and green, and has the advantages of low voltage, low power consumption, small size, light weight, long service life and high reliability, and is rapidly applied to the fields of traffic signal lamps, mobile phone backlights, outdoor full-color display screens, city landscape lighting, car interior and exterior lamps, tunnel lamps and the like. Therefore, the improvement of various performances of the LED is focused by the industry.

[0003] In the preparation of a GaN-based LED epitaxial layer, the characteristics of a buffer layer are an important factor affecting the electrical properties of the LED. In the growth of an LED epitaxial layer by MOCVD at home, the growth of the buffer layer is usually only TMAl doped or not doped at all. In order to improve the wavelength uniformity, the thickness of the buffer layer is thickened to different degrees, resulting in low light-emitting efficiency of the LED chip, increased energy consumption of the device and the like.

[0004] In order to solve the above problems, the Chinese patent with the publication number CN104009136A discloses an LED epitaxial layer growth method for improving the light-emitting efficiency, which is composed of a low-temperature grown P-type AlGaN / GaN superlattice layer and a high-temperature grown P-type AlGaN / GaN superlattice layer, effectively reduces the Droop effect of the LED chip under a large current density, improves the injection efficiency of the carriers, and improves the light-emitting efficiency of the device.

[0005] However, the above scheme can only improve the light-emitting efficiency of the LED chip within a limited range, and still cannot meet the increasingly high demand in the market. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a GaN-based epitaxial layer growth method for improving the light-emitting efficiency of an LED chip, and to improve the light-emitting efficiency of the LED chip.

[0007] In order to solve the above technical problem, one technical scheme adopted by the present application is as follows: a GaN-based epitaxial layer growth method for improving the light-emitting efficiency of an LED chip, comprising the following steps:

[0008] S1: placing an AlN substrate into a reaction cavity of a metal organic chemical vapor deposition device;

[0009] S2: set the reaction cavity temperature to 780-880 degrees, the pressure to 100-200 mbar, and introduce ammonia, nitrogen, 100-300 sccm of TMGa2, 400-600 sccm of TMIn and 25-200 sccm of TMAl, and keep for 5-20 seconds; grow a 0.01-0.03 um doped buffer layer on the substrate;

[0010] S3: set the reaction cavity pressure to 100-200 mbar and the temperature to 780-880 degrees, and introduce ammonia, nitrogen, 100-300 sccm of TMGa2; keep for 20-60 seconds; grow a 0.1-0.15 um undoped buffer layer on the doped buffer layer;

[0011] S4: grow a U-shaped GaN layer on the undoped buffer layer;

[0012] S5: grow an N-type GaN layer on the U-shaped GaN layer;

[0013] S6: grow a multi-quantum well active region layer on the N-type GaN layer;

[0014] S7: grow a low-temperature P-type GaN layer on the multi-quantum well active region layer;

[0015] S8: grow a high-temperature P-type GaN layer on the low-temperature P-type GaN layer;

[0016] S9: complete the growth of the GaN-based epitaxial layer.

[0017] The GaN-based epitaxial layer growth method for improving the light emitting efficiency of an LED chip provided by the application has the advantages that: the S2 and S3 divide the buffer layer of the LED chip into two steps and form a composite structure. The buffer layer of the GaN-based epitaxial layer includes a doped buffer layer (the doping element is TMIN and AL) with high doping concentration and an undoped buffer layer. This structure improves the epitaxial stress of the epitaxial layer, thins the buffer layer and improves the light emitting efficiency of the LED chip. The brightness of the GaN-based epitaxial layer is improved by 2%-5% compared with the brightness of a conventional LED structure. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a whole structure schematic view of the GaN-based epitaxial layer growth method for improving the light emitting efficiency of an LED chip according to the embodiment of the application;

[0019] Label explanation:

[0020] 1, AlN substrate; 2, doped buffer layer; 3, undoped buffer layer; 4, U-shaped GaN layer; 5, N-type GaN layer; 6, multi-quantum well active region layer; 7, low-temperature P-type GaN layer; 8, superlattice layer; 9, high-temperature P-type GaN layer. DETAILED DESCRIPTION

[0021] To make the technical contents of the present application, the purposes and effects achieved more clear, the following will be described in detail in combination with the embodiments and the accompanying drawings.

[0022] A GaN-based epitaxial layer growth method for improving the light-emitting efficiency of LED chips, comprising the following steps:

[0023] S1: placing the AlN substrate 1 into the reaction cavity of a metal organic chemical vapor deposition device;

[0024] S2: setting the reaction cavity temperature to 780-880 degrees, the pressure to 100-200 mbar, and introducing ammonia, nitrogen, 100-300 sccm of TMGa2, 400-600 sccm of TMIn, and 25-200 sccm of TMAl, and maintaining for 5-20 seconds; growing a 0.01-0.03 um doped buffer layer 2 on the substrate;

[0025] S3: setting the reaction cavity pressure to 100-200 mbar and the temperature to 780-880 degrees, and introducing ammonia, nitrogen, and 100-300 sccm of TMGa2, and maintaining for 20-60 seconds; growing a 0.1-0.15 um undoped buffer layer 3 on the doped buffer layer;

[0026] S4: growing a U-shaped GaN layer 4 on the undoped buffer layer;

[0027] S5: growing an N-type GaN layer 5 on the U-shaped GaN layer;

[0028] S6: growing a multi-quantum well active region layer 6 on the N-type GaN layer;

[0029] S7: growing a low-temperature P-type GaN layer 7 on the multi-quantum well active region layer;

[0030] S8: growing a high-temperature P-type GaN layer 9 on the low-temperature P-type GaN layer;

[0031] S9: completing the growth of the GaN-based epitaxial layer.

[0032] The beneficial effects of the present application are known from the above description: the GaN-based epitaxial layer growth method for improving the light-emitting efficiency of the LED chip provided by the present application, wherein the S2 and S3 divide the Buffer layer of the LED chip into two steps and are composed of two structures. The Buffer layer of the GaN-based epitaxial layer comprises a high-doped Buffer layer (doped elements are TMIN and AL) and an undoped Buffer layer, which improves the epitaxial stress of the epitaxial layer, thins the Buffer layer, and improves the light-emitting efficiency of the LED chip; the brightness of the GaN-based epitaxial layer is improved by 2%-5% compared with the conventional LED structure.

[0033] Further, the S4 is specifically:

[0034] The reaction cavity pressure is set to 250-350 mbar, the temperature is set to 1100-1300 degrees, and nitrogen, hydrogen, ammonia and TMGa2 are introduced; the undoped Buffer layer is grown with a U-shaped GaN layer of 2-3 microns for 11-13 minutes.

[0035] From the above description, the above setting provides a simple and efficient method for growing a U-shaped GaN layer.

[0036] Further, the S5 is specifically:

[0037] The reaction cavity temperature is set to 1000-1100 degrees, the pressure is set to 500-1000 mbar, and a N-type GaN layer of 2-3 microns is grown on the U-shaped GaN layer.

[0038] From the above description, the above setting provides a simple and efficient method for growing a N-type GaN layer. The N-type GaN layer is used for setting an electrode.

[0039] Further, the S6 is specifically: while introducing ammonia, hydrogen, nitrogen and 25-40 sccm of TMGa2 into the reaction cavity, TMIn is intermittently introduced, and a periodic InGaN / GaN multi-quantum well active region layer of 0.15-0.2 microns is grown on the N-type GaN layer;

[0040] From the above description, the In element is doped into the quantum well layer, which helps to reduce the working voltage of the LED chip.

[0041] Further, the S6 is specifically:

[0042] The reaction cavity pressure is set to 500-1000 mbar, the temperature is set to 700-800 degrees, while ammonia, hydrogen, nitrogen and 25-40 sccm of TMGa2 are introduced, 1200-1500 sccm of TMIn is intermittently introduced, so that a periodic InGaN / GaN multi-quantum well active region layer is grown on the N-type GaN layer, the period number of InGaN / GaN is 10-16; the thickness of the multi-quantum well active region layer is 0.15-0.2 microns, and the doping concentration of In is 1E+20-2E+20 atom / cm 3 .

[0043] From the above description, it can be seen that the above setting provides a simple and efficient method for growing a multi-quantum active region layer, and limits the period number of InGaN / GaN and the doping concentration of In, thereby maximizing the operating voltage of the LED chip and improving the light emitting efficiency of the LED chip.

[0044] Further, the S7 is specifically:

[0045] The reaction cavity temperature is set to 600-700 degrees, the pressure is set to 300-800 mbar, 55000-65000 sccm of NH3 and 25-50 sccm of TMGa2 are introduced, and a low-temperature P-type GaN layer with a thickness of 60-90 nm is grown on the multi-quantum well active region layer.

[0046] From the above description, it can be seen that the above setting provides a simple and efficient method for growing a low-temperature P-type GaN layer.

[0047] Further, it further includes a step S7.5 between S7 and S8;

[0048] S7.5: introducing NH3, TMGa2, Cp2Mg and TMAl into the reaction cavity, so that a periodic AlGaN / GaN superlattice layer is grown on the low-temperature P-type GaN layer;

[0049] The S8 is specifically growing a high-temperature P-type GaN layer on the superlattice layer.

[0050] From the above description, it can be seen that the above step forms a superlattice layer 8 between the P-type GaN layers, which is beneficial to reduce the Droop effect of the LED chip under a large current density, improve the injection efficiency of the carriers, and improve the light emitting efficiency of the device.

[0051] Further, the S7.5 is specifically:

[0052] The temperature of the reaction cavity is set to 700-950 degrees, the pressure is set to 300-800 mbar, 30000-60000 sccm of NH3, 30-50 sccm of TMGa2, 1500-2000 sccm of Cp2Mg and 150-200 sccm of TMAl are introduced, and a periodic AlGaN / GaN superlattice layer is grown on the low-temperature P-type GaN layer; the period of the AlGaN / GaN is 5-10, the single-layer thickness of the AlGaN is 4-6 nm, and the thickness ratio of the AlGaN layer to the GaN layer in a single period is 1:1-3:1; the thickness of the superlattice layer is 50-70 nm, the doping concentration of Mg is 1E+18-1E+19 atom / cm 3 , and the doping concentration of Al is 1E+17-1E+18 atom / cm 3 ;

[0053] S8 is specifically growing a high-temperature P-type GaN layer on the superlattice layer.

[0054] It can be known from the above description that the above setting provides a simple and efficient method for growing a superlattice layer, and the incorporation of Al and Mg elements in the superlattice layer is beneficial to improving the light-emitting efficiency of the LED chip.

[0055] Further, S8 is specifically:

[0056] The temperature of the reaction cavity is set to 900-1050 degrees, the pressure is set to 600-1000 mbar, 60000-75000 sccm of NH3, 25-50 sccm of TMGa2 and 2000-3000 sccm of Cp2Mg are introduced, and a doped high-temperature P-type GaN layer is grown on the superlattice layer; the thickness of the high-temperature P-type GaN layer is 60-90 nm, and the doping concentration of Mg is 1E+20-3E+20 atom / cm 3 .

[0057] It can be known from the above description that the above setting provides a simple and efficient method for growing a high-temperature P-type GaN layer, and the incorporation of Mg elements in the high-temperature P-type GaN layer is beneficial to improving the light-emitting efficiency of the LED chip.

[0058] Embodiment one

[0059] The embodiment provides a GaN-based epitaxial layer growth method for improving the light-emitting efficiency of an LED chip, including the following steps:

[0060] S1: placing an AlN substrate into a reaction cavity of a metal organic chemical vapor deposition device;

[0061] S2: set the temperature of the reaction chamber to 780 degrees, the pressure to 100 mbar, and introduce ammonia, nitrogen, 100 sccm of TMGa2, 400-600 sccm of TMIn and 25-200 sccm of TMAl, and maintain for 5-20 seconds; grow a doped buffer layer of 0.01-0.03 um on the substrate;

[0062] S3: set the pressure of the reaction chamber to 100 mbar and the temperature to 780 degrees, and introduce ammonia, nitrogen, 100-300 sccm of TMGa2; maintain for 20-60 seconds; grow an undoped buffer layer of 0.1-0.15 um on the doped buffer layer;

[0063] S4: set the pressure of the reaction chamber to 250 mbar and the temperature to 1100 degrees, and introduce nitrogen, hydrogen, ammonia and TMGa2; maintain for 11-13 minutes; grow a U-shaped GaN layer of 2-3 microns on the undoped buffer layer;

[0064] S5: set the temperature of the reaction chamber to 1000-1100 degrees and the pressure to 500-1000 mbar, and grow a N-type GaN layer of 2-3 microns on the U-shaped GaN layer;

[0065] S6: set the pressure of the reaction chamber to 500-1000 mbar and the temperature to 700-800 degrees, and introduce ammonia, hydrogen, nitrogen and 25-40 sccm of TMGa2, and intermittently introduce 1200-1500 sccm of TMIn, so as to grow a periodic InGaN / GaN multi-quantum well active region layer on the N-type GaN layer, the period number of InGaN / GaN being 10-16; the multi-quantum well active region layer has a thickness of 0.15-0.2 microns and an In doping concentration of 1E+20-2E+20 atom / cm 3 ;

[0066] S7: set the temperature of the reaction chamber to 600 degrees and the pressure to 300 mbar, and introduce 55000-65000 sccm of NH3 and 25-50 sccm of TMGa2, so as to grow a low-temperature P-type GaN layer of 60-90 nm in thickness on the multi-quantum well active region layer;

[0067] S8: set the reaction cavity temperature to 700 degrees, the pressure to 300-800 mbar, and introduce 30000-60000 sccm of NH3, 30-50 sccm of TMGa2, 1500-2000 sccm of Cp2Mg and 150-200 sccm of TMAl, so as to grow a periodic AlGaN / GaN superlattice layer on the low-temperature P-type GaN layer; the period of the AlGaN / GaN is 5-10, the single-layer thickness of the AlGaN is 4-6 nm, and the thickness ratio of the AlGaN and GaN layers in a single period is 1:1-3:1; the thickness of the superlattice layer is 50 nm, the doping concentration of Mg is 1E+18 atom / cm2, the doping concentration of Al is 1E+17-1E+18 atom / cm2. 3 3

[0068] S9: set the reaction cavity temperature to 900 degrees, the pressure to 600-1000 mbar, and introduce 60000 sccm of NH3, 25-50 sccm of TMGa2 and 2000 sccm of Cp2Mg, so as to grow a doped high-temperature P-type GaN layer on the superlattice layer; the thickness of the high-temperature P-type GaN layer is 60-90 nm, and the doping concentration of Mg is 1E+20-3E+20 atom / cm2. 3

[0069] S10: complete the growth of the GaN-based epitaxial layer.

[0070] Embodiment Two

[0071] The embodiment provides a GaN-based epitaxial layer growth method for improving the light-emitting efficiency of an LED chip, which comprises the following steps:

[0072] S1: place an AlN substrate into a reaction cavity of a metal organic chemical vapor deposition device;

[0073] S2: set the reaction cavity temperature to 800 degrees, the pressure to 150 mbar, and introduce ammonia, nitrogen, 200 sccm of TMGa2, 500 sccm of TMIn and 100 sccm of TMAl, and maintain for 12-15 seconds; so as to grow a 0.01-0.03 um doped buffer layer on the substrate;

[0074] S3: set the reaction cavity pressure to 150 mbar and the temperature to 800 degrees, and introduce ammonia, nitrogen and 100-300 sccm of TMGa2; maintain for 20-60 seconds; so as to grow a 0.1-0.15 um undoped buffer layer on the doped buffer layer;

[0075] ​​​S4: set the reaction cavity pressure 250 mbar, temperature 1100 degrees, into the nitrogen, hydrogen, ammonia and TMGa2; last 11-13 minutes, make the growth of 2-3 microns of U-shaped GaN layer on the undoped buffer layer;

[0076] S5: set the reaction cavity temperature 1000-1100 degrees, pressure 500-1000 mbar, grow 2-3 microns of N-type GaN layer on the U-shaped GaN layer;

[0077] S6: set the reaction cavity pressure 500 mbar, temperature 700 degrees, while into the ammonia, hydrogen, nitrogen and 25 sccm of TMGa2, intermittent into 1200 sccm of TMIn, make the growth of periodic InGaN / GaN multi-quantum well active region layer on the N-type GaN layer, the period number of InGaN / GaN is 10; the multi-quantum well active region layer thickness is 0.15-0.2 microns, the In doping concentration is 1E+20-2E+20 atom / cm 3 ;

[0078] S7: set the reaction cavity temperature 650 degrees, pressure 550 mbar, into 55000-65000 sccm of NH3 and 25-50 sccm of TMGa2, grow the thickness of 60-90 nm of low-temperature P-type GaN layer on the multi-quantum well active region layer;

[0079] S8: set the reaction cavity temperature 700 degrees, pressure 300 mbar, into 30000 sccm of NH3, 30 sccm of TMGa2, 1500 sccm of Cp2Mg and 150 sccm of TMAl, make the growth of periodic AlGaN / GaN superlattice layer on the low-temperature P-type GaN layer; the period of AlGaN / GaN is 5, the single layer thickness of AlGaN is 4-6 nm, the thickness ratio of AlGaN and GaN layer in a single period is 1:1-3:1; the superlattice layer thickness is 50-70 nm, the Mg doping concentration is 1E+18-1E+19 atom / cm 3 , the Al doping concentration is 1E+17-1E+18 atom / cm 3 ;

[0080] S9: set the reaction cavity temperature 900 degrees, pressure 600 mbar, into 60000 sccm of NH3, 25 sccm of TMGa2 and 2000 sccm of Cp2Mg, grow the doped high-temperature P-type GaN layer on the superlattice layer; the high-temperature P-type GaN layer thickness is 78 nm, the Mg doping concentration is 1E+20-3E+20 atom / cm 3 ;

[0081] S10: completing the growth of the GaN-based epitaxial layer.

[0082] Embodiment Three

[0083] The embodiment provides a GaN-based epitaxial layer growth method for improving the light emitting efficiency of an LED chip, comprising the following steps:

[0084] S1: placing an AlN substrate into a reaction cavity of a metal organic chemical vapor deposition device;

[0085] S2: setting the temperature of the reaction cavity to 880 degrees, the pressure to 200 mbar, and introducing ammonia, nitrogen, 300 sccm of TMGa2, 400-600 sccm of TMIn and 25-200 sccm of TMAl, and maintaining for 5-20 seconds; and growing a 0.03 um doped buffer layer on the substrate;

[0086] S3: setting the pressure of the reaction cavity to 100-200 mbar and the temperature to 780-880 degrees, and introducing ammonia, nitrogen and 100-300 sccm of TMGa2; and maintaining for 20-60 seconds; and growing a 0.15 um undoped buffer layer on the doped buffer layer;

[0087] S4: setting the pressure of the reaction cavity to 250-350 mbar and the temperature to 1100-1300 degrees, and introducing nitrogen, hydrogen, ammonia and TMGa2; and maintaining for 11-13 minutes; and growing a 3 um U-shaped GaN layer on the undoped buffer layer;

[0088] S5: setting the temperature of the reaction cavity to 1000-1100 degrees and the pressure to 1000 mbar, and growing a 3 um N-type GaN layer on the U-shaped GaN layer;

[0089] S6: setting the pressure of the reaction cavity to 500-1000 mbar and the temperature to 800 degrees, and introducing ammonia, hydrogen, nitrogen and 25-40 sccm of TMGa2, and intermittently introducing 1200-1500 sccm of TMIn, so as to grow a periodic InGaN / GaN multi-quantum well active region layer on the N-type GaN layer, the period number of the InGaN / GaN is 10-16; the thickness of the multi-quantum well active region layer is 0.2 um, and the doping concentration of In is 2E+20 atom / cm 3 ;

[0090] S7: setting the temperature of the reaction cavity to 700 degrees and the pressure to 300-800 mbar, and introducing 55000-65000 sccm of NH3 and 50 sccm of TMGa2, so as to grow a 60-90 nm low-temperature P-type GaN layer on the multi-quantum well active region layer;

[0091] S8: set the reaction cavity temperature to 700-950 degrees, the pressure to 300-800 mbar, and introduce 30000-60000 sccm of NH3, 30-50 sccm of TMGa2, 1500-2000 sccm of Cp2Mg and 200 sccm of TMAl, so as to grow a periodic AlGaN / GaN superlattice layer on the low-temperature P-type GaN layer; the period of the AlGaN / GaN is 8-10, the single-layer thickness of the AlGaN is 4-6 nm, and the thickness ratio of the AlGaN and GaN layers in a single period is 1:1-3:1; the thickness of the superlattice layer is 50-70 nm, and the doping concentration of Mg is 1E+18-1E+19 atom / cm 3 , and the doping concentration of Al is 1E+18 atom / cm 3 ;

[0092] S9: set the reaction cavity temperature to 900-1050 degrees, the pressure to 600-1000 mbar, and introduce 60000-75000 sccm of NH3, 25-50 sccm of TMGa2 and 3000 sccm of Cp2Mg, so as to grow a doped high-temperature P-type GaN layer on the superlattice layer; the thickness of the high-temperature P-type GaN layer is 60-90 nm, and the doping concentration of Mg is 3E+20 atom / cm 3 ;

[0093] S10: complete the growth of the GaN-based epitaxial layer.

[0094] Comparative Example 1

[0095] Table 1

[0096]

[0097] In Table 1, the sample 1 is a plurality of LED chips produced by using the GaN-based epitaxial layer growth method for improving the light-emitting efficiency of LED chips according to the present application.

[0098] The sample 2 is a plurality of LED chips produced by using a conventional method. The conventional method is different from Example 2 only in that the steps S2 and S3 are replaced by growing a buffer layer without doping TMIn on the AlN substrate.

[0099] The parameters in Table 1 are the average values of the parameters of the plurality of LED chips of the sample 1 or the average values of the parameters of the plurality of LED chips of the sample 2.

[0100] As can be seen from Table 1, the LED chips produced by using the GaN-based epitaxial layer growth method for improving the light-emitting efficiency of LED chips according to the present application have a significantly reduced working voltage, and the luminous flux is increased by 5.5% compared with the conventional LED chips. Therefore, the scheme of the present application effectively improves the light-emitting efficiency of LED chips.

[0101] The above merely illustrates the embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent transformation or direct or indirect application in related technical fields based on the content of the present application specification and drawings are also included in the patent protection scope of the present application.

Claims

1. A method for growing a GaN-based epitaxial layer to improve the luminous efficiency of LED chips, characterized in that, Includes the following steps: S1: Place the AlN substrate into the reaction chamber of the metal-organic chemical vapor deposition equipment; S2: Set the reaction chamber temperature to 780-880 degrees Celsius and the pressure to 100-200 mbar. Introduce ammonia, nitrogen, 100-300 sccm of TMGa2, 400-600 sccm of TMIn, and 25-200 sccm of TMAl for 5-20 seconds to grow a 0.01-0.03 μm doped buffer layer on the substrate. S3: Set the reaction chamber pressure to 100-200 mbar and the temperature to 780-880 degrees. Introduce ammonia, nitrogen, and 100-300 sccm of TMGa2. Continue for 20-60 seconds to grow an undoped buffer layer of 0.1-0.15 μm on the doped buffer layer. S4: Grow a U-shaped GaN layer on an undoped buffer layer; S5: Grow an N-type GaN layer on a U-type GaN layer; S6: Growth of a multi-quantum-well active region layer on an N-type GaN layer; S7: Low-temperature P-type GaN layer is grown on the multi-quantum-well active region layer; S8: Growing a high-temperature P-type GaN layer on a low-temperature P-type GaN layer; S9: Complete the growth of the GaN-based epitaxial layer.

2. The method for growing a GaN-based epitaxial layer to improve the luminous efficiency of an LED chip according to claim 1, characterized in that, Specifically, S4 is: Set the reaction chamber pressure to 250-350 mbar and the temperature to 1100-1300 degrees Celsius, and introduce nitrogen, hydrogen, ammonia, and TMGa2; continue for 11-13 minutes to grow a 2-3 micrometer U-shaped GaN layer on the undoped buffer layer.

3. The method for growing a GaN-based epitaxial layer to improve the luminous efficiency of an LED chip according to claim 1, characterized in that, Specifically, S5 is: Set the reaction chamber temperature to 1000-1100 degrees Celsius and the pressure to 500-1000 mbar, and grow an N-type GaN layer of 2-3 micrometers on the U-type GaN layer.

4. The method for growing a GaN-based epitaxial layer to improve the luminous efficiency of an LED chip according to claim 1, characterized in that, Specifically, S6 involves introducing ammonia, hydrogen, nitrogen, and 25-40 sccm of TMGa2 into the reaction chamber while intermittently introducing TMIn, thereby growing periodic InGaN / GaN multi-quantum well active regions of 0.15-0.2 micrometers on the N-type GaN layer.

5. The method for growing a GaN-based epitaxial layer to improve the luminous efficiency of an LED chip according to claim 4, characterized in that, Specifically, S6 is: The reaction chamber pressure is set to 500-1000 mbar and the temperature to 700-800 degrees Celsius. While ammonia, hydrogen, nitrogen, and 25-40 sccm of TMGa2 are introduced, 1200-1500 sccm of TMIn are intermittently introduced to grow periodic InGaN / GaN multi-quantum-well active regions on the N-type GaN layer. The period number of the InGaN / GaN is 10-16. The thickness of the multi-quantum-well active region is 0.15-0.2 micrometers, and the In doping concentration is 1E+20-2E+20 atom / cm². 3 .

6. The method for growing a GaN-based epitaxial layer to improve the luminous efficiency of an LED chip according to claim 1, characterized in that, Specifically, S7 is: The reaction chamber temperature was set to 600-700 degrees Celsius and the pressure to 300-800 mbar. 55,000-65,000 sccm of NH3 and 25-50 sccm of TMGa2 were introduced to grow a low-temperature P-type GaN layer with a thickness of 60-90 nm on the multi-quantum-well active region layer.

7. The method for growing a GaN-based epitaxial layer to improve the luminous efficiency of an LED chip according to claim 1, characterized in that, It also includes step S7.5 between S7 and S8; S7.5: Introduce NH3, TMGa2, Cp2Mg and TMAl into the reaction chamber to grow a periodic AlGaN / GaN superlattice layer on the low-temperature P-type GaN layer. Specifically, S8 involves growing a high-temperature P-type GaN layer on a superlattice layer.

8. The method for growing a GaN-based epitaxial layer to improve the luminous efficiency of an LED chip according to claim 7, characterized in that, Specifically, S7.5 is as follows: The reaction chamber temperature is set to 700-950 degrees Celsius, and the pressure to 300-800 mbar. 30,000-60,000 sccm of NH3, 30-50 sccm of TMGa2, 1500-2000 sccm of Cp2Mg, and 150-200 sccm of TMAl are introduced to grow a periodic AlGaN / GaN superlattice layer on a low-temperature p-type GaN layer. The AlGaN / GaN period is 5-10, the AlGaN monolayer thickness is 4-6 nm, and the thickness ratio of the AlGaN to GaN layers in a single period is 1:1-3:

1. The superlattice layer thickness is 50-70 nm, and the Mg doping concentration is 1E+18-1E+19 atom / cm³. 3 The doping concentration of Al is 1E+17-1E+18 atoms / cm³ 3 ; Specifically, S8 involves growing a high-temperature P-type GaN layer on a superlattice layer.

9. The method for growing a GaN-based epitaxial layer to improve the luminous efficiency of an LED chip according to claim 1, characterized in that, Specifically, S8 is: The reaction chamber temperature is set to 900-1050 degrees Celsius, and the pressure to 600-1000 mbar. NH3 is introduced at 60000-75000 sccm, TMGa2 at 25-50 sccm, and Cp2Mg at 2000-3000 sccm. A high-temperature doped p-type GaN layer is grown on the superlattice layer. The thickness of the high-temperature p-type GaN layer is 60-90 nm, and the Mg doping concentration is 1E+20-3E+20 atom / cm³. 3 .

Images