High reverse voltage high-power LED epitaxial structure and growth method thereof

Abstract

The present application relates to the technical field of LED chip, in particular to a high-reverse-voltage high-power LED epitaxial structure and a growth method thereof. The growth method of the present application grows an InGaN layer as an interface treatment layer on a high-temperature P-type GaN layer. The interface treatment layer utilizes the active characteristics of In atoms to make the InGaN more inclined to three-dimensional growth, which can fill the V-type defects with less thickness, effectively reduce the leakage channel, and improve the reverse voltage and other performances. Compared with the conventional P-type GaN layer filling V-type defects, the thickness of InGaN is thinner, and the influence on the light efficiency and luminous efficiency is smaller. The brightness performance is not affected while the reverse voltage is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of LED chip, and particularly relates to a high-reverse-voltage high-power LED epitaxial structure and a growth method thereof. BACKGROUND

[0002] In recent years, with the development of semiconductor material and device design level and preparation technology, the performance index of light emitting diode (LED) is rapidly improved, and the LED is widely applied and researched in outdoor lighting, automobile lamp, backlight display and microelectronic device, etc., wherein the high-power LED chip as the core of white light LED lighting has become a research hotspot. The light emitting efficiency of the high-power LED decreases with the increase of current, and the reverse voltage sharply decreases with the increase of chip size, which hinders the application of the LED in high-power lighting.

[0003] A epitaxial growth method for improving reverse voltage of GaN-based LED is disclosed in Chinese patent application No. 202310168083.4, which improves the stress and defect density of the multi-quantum well active region layer by changing the In content and passing a small amount of H2 to process the interface of the stress release layer, so as to improve the reverse voltage of the LED chip. This method can improve the reverse voltage of the LED chip by adjusting the In content of the stress release layer to affect the size of the V-shaped opening, but the performance of ESD is reduced. How to improve the reverse voltage without affecting the performance of ESD and brightness is of great importance to the development of high-power LED. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a high-power LED epitaxial structure and a growth method thereof, which can improve the reverse voltage without affecting the brightness performance.

[0005] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows: a growth method of a high-reverse-voltage high-power LED epitaxial structure, comprising the following steps: growing a buffer layer, a U-shaped GaN layer, an N-type GaN layer, a multi-quantum well active region layer and a P-type GaN layer on a substrate in sequence; the P-type GaN layer comprises a low-temperature P-type GaN layer, an electron blocking layer, an InGaN layer and a high-temperature P-type GaN layer grown in sequence.

[0006] Another technical scheme adopted by the present application is a high-reverse-voltage high-power LED epitaxial structure prepared by the above growth method.

[0007] The growth method of the application has the beneficial effects that: the growth method of the application grows an InGaN layer as an interface treatment layer on the high-temperature P-type GaN layer, the interface treatment layer uses the active characteristics of In atoms to make the InGaN more inclined to three-dimensional growth, and the V-type defects can be filled with less thickness, and the leakage channel, the reverse voltage and other performances are effectively reduced. Compared with the conventional method of filling the V-type defects with the P-type GaN layer, the thickness of the InGaN is thinner, and the influence on the light efficiency and the luminous efficiency is smaller, and the brightness performance is not affected while the reverse voltage is improved. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 Fig. 1 is a structural schematic diagram of an epitaxial structure of a specific embodiment of the application;

[0009] Figure 2 Fig. 2 is a comparison diagram of reverse voltages of Examples 1-3 and Comparative Examples 1-3 of the application;

[0010] Figure 3 Fig. 3 is a comparison diagram of light efficiencies of Examples 1-3 and Comparative Examples 1-3 of the application;

[0011] Label explanation: 1, substrate; 2, buffer layer; 3, U-type GaN layer; 4, N-type GaN layer; 5, current spreading layer; 6, multi-quantum well light emitting layer; 7, low-temperature P-type GaN layer; 8, electron blocking layer; 9, InGaN layer; 10, high-temperature P-type GaN layer. DETAILED DESCRIPTION

[0012] To explain the technical content, the purposes and effects of the application in detail, the following will be described in combination with the embodiments and the drawings.

[0013] Please refer to Figure 1 A growth method of a high-reverse-voltage high-power LED epitaxial structure, comprising the following steps: growing a buffer layer, a U-type GaN layer, an N-type GaN layer, a multi-quantum well active region layer and a P-type GaN layer on a substrate in sequence; the P-type GaN layer comprises a low-temperature P-type GaN layer, an electron blocking layer, an InGaN layer and a high-temperature P-type GaN layer grown in sequence.

[0014] As can be known from the above description, the application has the beneficial effects that: there is a large lattice mismatch and thermal mismatch between the gallium nitride material and the sapphire substrate, which leads to a large stress in the epitaxial growth, and then generates V-type defects, especially after the low-temperature growth of the multi-quantum well light emitting layer, the V-type defect opening reaches the maximum, and the leakage channel generated by the V-type defects leads to the reduction of ESD (electrostatic discharge) and the reduction of reverse voltage. The common method is to grow a P-type GaN layer with sufficient thickness to fill the V-type defects, but the thickness of the P-type GaN layer is thicker, which reduces the light efficiency and affects the luminous efficiency.

[0015] The present application grows an InGaN layer as an interface treatment layer on the high-temperature P-type GaN layer, uses the active characteristics of In atoms, makes the InGaN more inclined to three-dimensional growth, can fill the V-type defects with less thickness, effectively reduces the leakage channel, improves the reverse voltage and other performances; the thickness of the InGaN is thin, and the influence on the light emission efficiency and the light emission efficiency is small. The interface treatment layer is grown on the electron blocking layer, before the high-temperature P-type GaN layer, at this time, the opening of the V-type defect is the largest, and the filling effect is the best.

[0016] Further, the low-temperature P-type GaN layer and the high-temperature P-type GaN layer are doped with Mg, and the electron blocking layer and the InGaN layer are undoped.

[0017] From the above description, it can be known that the Mg doped layer absorbs light, which reduces the light emission efficiency and affects the light emission efficiency, therefore, the InGaN layer and the electron blocking layer are designed to be undoped; the low-temperature P-type GaN layer and the high-temperature P-type GaN layer are doped with Mg, which can provide sufficient holes.

[0018] Further, before growing the buffer layer, the substrate is first placed into the reaction chamber, and H2 is used to purge the reaction chamber; then the H2 purging is closed, the pressure of the reaction chamber is set to 500-600 mbar, the temperature is set to 1000-1200℃, and the process is continued for 7-10 min; then H2 and NH3 are used to purge the reaction chamber.

[0019] From the above description, it can be known that the above method is used to remove impurities in the reaction chamber, and the gas required for the subsequent reaction is introduced in advance, the substrate is preprocessed by increasing the temperature and pressure of the reaction chamber, and the quality of the structure on the substrate in the subsequent growth is improved.

[0020] Further, the buffer layer is grown in the reaction chamber, the pressure of the reaction chamber is 100-200 mbar, the temperature is 800-900℃, 60-80 sccm of TMGa and 25-45 sccm of TMAl are introduced into the reaction chamber at the same time, and the process is continued for 4-6 min to grow a buffer layer with a thickness of 0.01-0.02 μm.

[0021] From the above description, a simple and efficient method for growing a buffer layer is provided, and a high-quality buffer layer can be grown.

[0022] Further, the U-shaped GaN layer is grown in the reaction chamber, the pressure of the reaction chamber is 150-500 mbar, the temperature is 900-1100℃, 300-400 sccm of TMGa is introduced into the reaction chamber at the same time, and the process is continued for 6-30 min to grow a U-shaped GaN layer.

[0023] From the above description, the above setting provides a simple and efficient method for growing U-shaped GaN layer, and realizes preparation of high-quality U-shaped GaN layer.

[0024] Further, the N-type GaN layer is grown in a reaction chamber, the pressure of the reaction chamber is 500-1000 mbar, Si is used as a doping element, and the doping concentration is 1E+19-2E+19 atom / cm 3 , and the thickness of the N-type GaN layer is 2-3 microns.

[0025] Further, the electron blocking layer is a P-type AlGaN layer.

[0026] Further, the multi-quantum well active region layer comprises a current spreading layer and a multi-quantum well light emitting layer grown in sequence.

[0027] Further, the current spreading layer is grown in a reaction chamber, the temperature of the reaction chamber is 700-950 DEG C, and 30000-60000 sccm of NH3 and 30-50 sccm of TMGa are introduced into the reaction chamber at the same time; Si is used as a doping element, and the doping concentration is 1E+16-2E+18 atom / cm 3 .

[0028] Further, the multi-quantum well light emitting layer comprises a well layer and a barrier layer, the well layer is InGaN, the barrier layer is GaN, one period is formed by growing the well layer and the barrier layer once, and the period number is 10-16.

[0029] Further, the multi-quantum well light emitting layer is grown in a reaction chamber, and TMAl is introduced into the reaction chamber when the last barrier layer is grown, and the flow rate of TMAl is linearly decreased from 180 sccm to 0 sccm.

[0030] From the above description, Al is doped in the last barrier layer of the multi-quantum well light emitting layer, and the mole number of Al is linearly decreased in the direction away from the substrate, so that the ESD performance and the light emitting efficiency of the LED can be maximally improved.

[0031] Further, when the well layer is grown, the temperature of the reaction chamber is 700-800 DEG C, and 1200-1500 sccm of TMIn and 25-400 sccm of TEGa are introduced into the reaction chamber at the same time; the doping concentration of In of each well layer is 1E+20-2E+20 atom / cm 3 .

[0032] When the barrier layer is grown, the temperature of the reaction chamber is 800-950 DEG C, and 300-1000 sccm of TEGa is introduced into the reaction chamber at the same time.

[0033] Further, the thickness of the multi-quantum well light emitting layer is 0.15-0.2 microns.

[0034] Further, the growth of the low-temperature P-type GaN layer is carried out in a reaction chamber with a temperature of 700-950 DEG C and a pressure of 300-800 mbar, and 55000-65000 sccm of NH3, 25-50 sccm of TMGa and 3600 sccm of Cp2Mg are introduced into the reaction chamber, so as to grow a low-temperature P-type GaN layer with a Mg doping concentration of 1.1-5E+16 atom / cm 3 and a thickness of 20-80 nm.

[0035] As described above, the low-temperature P-type GaN can provide holes and protect the multi-quantum well active region from being damaged by high temperature, so as to maximize the performance and light emitting efficiency of the LED.

[0036] Further, the growth of the electron blocking layer is carried out in a reaction chamber with a temperature of 700-950 DEG C, and 30000-60000 sccm of NH3, 30-50 sccm of TMGa and 150-200 sccm of TMAl are introduced into the reaction chamber, so as to grow an electron blocking layer with an Al doping concentration of 1E+17-1E+18 atom / cm 3 and a thickness of 50-70 nm.

[0037] As described above, the present application provides a simple and efficient method for growing a P-type electron blocking layer.

[0038] Further, the growth of the InGaN layer is carried out in a reaction chamber with a temperature of 900-1050 DEG C and a pressure of 600-1000 mbar, and 30000-60000 sccm of NH3, 60000-85000 sccm of N2, 25-50 sccm of TMGa and 200-600 sccm of TMIn are introduced into the reaction chamber.

[0039] As described above, the present application utilizes the relatively active characteristic of In element under a pure N2 atmosphere to perform interface processing on the V-type defects extending from the light emitting layer, so as to generate an InGaN layer with a more flat interface and less leakage channel, and improve the reverse voltage.

[0040] Further, the InGaN layer has a thickness of 10-90 nm.

[0041] Further, the high-temperature P-type GaN layer is grown in a reaction chamber with a temperature of 900-1050 DEG C and a pressure of 600-1000 mbar, and 60000-75000 sccm of NH3, 25-50 sccm of TMGa and 2000-3000 sccm of Cp2Mg are introduced into the reaction chamber, so as to grow the high-temperature P-type GaN layer with a thickness of 60-90 nm.

[0042] As described above, the high-temperature P-type GaN layer can reduce the working voltage of the LED and improve the light-emitting efficiency of the LED.

[0043] Another technical solution of the present application is to use the high-reverse-voltage high-power LED epitaxial structure prepared by the above growth method.

[0044] Embodiment 1 of the present application is a growth method of a high-reverse-voltage high-power LED epitaxial structure, and the steps are as follows:

[0045] S1: the substrate is placed into a reaction chamber of a metal organic chemical vapor deposition device, and H2 is used to purge the reaction chamber; then the purging of H2 is closed, the pressure of the reaction chamber is set to 550 mbar, and the temperature is set to 1100 DEG C, which lasts for 8.5 min; and then H2 and NH3 are used to purge the reaction chamber.

[0046] S2: the pressure of the reaction chamber is set to 150 mbar, and the temperature is set to 850 DEG C, while 70 sccm of TMGa and 35 sccm of TMAl are introduced into the reaction chamber, which lasts for 5 min, so as to grow a buffer layer with a thickness of 0.015 μm on the substrate.

[0047] S3: the pressure of the reaction chamber is set to 325 mbar, and the temperature is set to 1000 DEG C, while 350 sccm of TMGa is introduced into the reaction chamber, which lasts for 18 min, so as to grow a U-shaped GaN layer on the buffer layer.

[0048] S4: the pressure of the reaction chamber is set to 750 mbar, Si is used as a doping element, and the doping concentration is 1.5E+19 atom / cm 3 , and a N-type GaN layer with a thickness of 2.5 μm is grown on the U-shaped GaN layer.

[0049] S5: the temperature of the reaction chamber is set to 800 DEG C, while 40000 sccm of NH3 and 40 sccm of TMGa are introduced into the reaction chamber; Si is used as a doping element, and the doping concentration is 2E+16 atom / cm 3 , and a current spreading layer with a thickness of 300 nm is grown on the N-type GaN layer.

[0050] S6: growing a multi-quantum well light-emitting layer with a thickness of 0.18 μm on the current spreading layer, the multi-quantum well light-emitting layer comprising well layers and barrier layers alternately grown, the well layers being InGaN, and the barrier layers being GaN, one cycle being formed by growing one well layer and one barrier layer, and the number of cycles being 13;

[0051] When the well layer is grown, the temperature of the reaction cavity is set to 750 ℃, and 1300 sccm of TMIn and 210 sccm of TEGa are introduced into the reaction cavity; the In doping concentration of each well layer is 1.5E+20 atom / cm 3 When the barrier layer is grown, the temperature of the reaction cavity is set to 850 ℃, and 600 sccm of TEGa is introduced into the reaction cavity; when the last barrier layer is grown, TMAl is introduced into the reaction cavity, and the flow rate of TMAl is linearly decreased from 180 sccm to 0 sccm, so that the mole number of Al in the last barrier layer is linearly decreased along the direction away from the substrate, and the ratio of the mole number of Al to the mole number of GaN is linearly decreased from 15% to 0%.

[0052] S7: setting the temperature of the reaction cavity to 850 ℃ and the pressure to 550 mbar, and introducing 60000 sccm of NH3, 35 ccm of TMGa and 3600 sccm of Cp2Mg into the reaction cavity, to grow a low-temperature P-type GaN layer with a Mg doping concentration of 3E+16 atom / cm 3 and a thickness of 60 nm on the multi-quantum well light-emitting layer.

[0053] S8: setting the temperature of the reaction cavity to 850 ℃, and introducing 40000 sccm of NH3, 40 sccm of TMGa and 170 sccm of TMAl into the reaction cavity, so that the Al doping concentration is 1.5E+17 atom / cm 3 and a P-type AlGaN electron blocking layer with a thickness of 60 nm is grown.

[0054] S9: setting the temperature of the reaction cavity to 975 ℃ and the pressure to 800 mbar, and introducing 60000 sccm of NH3, 67500 sccm of N2, 37.5 sccm of TMGa and 200 ccm of TMIn into the reaction cavity, to grow an InGaN layer with a thickness of 20 nm on the P-type electron blocking layer.

[0055] S10: setting the temperature of the reaction cavity to 955 ℃ and the pressure to 800 mbar, and introducing 67500 sccm of NH3, 37.5 sccm of TMGa and 2500 sccm of Cp2Mg into the reaction cavity, to grow a high-temperature P-type GaN layer with a thickness of 75 nm on the InGaN layer.

[0056] Embodiment 2 of the present application is:

[0057] Example 2 differs from Example 1 only in that:

[0058] S9: The temperature of the reaction chamber is set to 935℃, the pressure is set to 800mbar, 60000sccm of NH3, 67500sccm of N2, 37.5sccm of TMGa and 200sccm of TMIn are introduced into the reaction chamber, and an InGaN layer with a thickness of 20nm is grown on the P-type electron blocking layer.

[0059] Example 3 of the present application is:

[0060] Example 3 differs from Example 1 only in that:

[0061] S9: The temperature of the reaction chamber is set to 935℃, the pressure is set to 800mbar, 60000sccm of NH3, 87500sccm of N2, 37.5sccm of TMGa and 200sccm of TMIn are introduced into the reaction chamber, and an InGaN layer with a thickness of 40nm is grown on the P-type electron blocking layer.

[0062] Example 4 of the present application is: a growth method of a high-reverse-voltage high-power LED epitaxial structure, the steps are as follows:

[0063] S1: The substrate is placed in the reaction chamber of the metal organic chemical vapor deposition device, and H2 is used to purge the reaction chamber; then the H2 purge is closed, the pressure of the reaction chamber is set to 500mbar, the temperature is set to 1200℃, and the process is continued for 7min; then H2 and NH3 are used to purge the reaction chamber.

[0064] S2: The pressure of the reaction chamber is set to 100mbar, the temperature is set to 900℃, 60sccm of TMGa and 25sccm of TMAl are introduced into the reaction chamber, and the process is continued for 4min, thereby growing a buffer layer with a thickness of 0.01μm on the substrate.

[0065] S3: The pressure of the reaction chamber is set to 150mbar, the temperature is set to 1100℃, 300sccm of TMGa is introduced into the reaction chamber, and the process is continued for 6min, thereby growing a U-shaped GaN layer on the buffer layer.

[0066] S4: The pressure of the reaction chamber is set to 500mbar, Si is used as the doping element, the doping concentration is 1E+19atom / cm 3 , and a N-type GaN layer with a thickness of 2μm is grown on the U-shaped GaN layer.

[0067] S5: set the temperature of the reaction chamber to 700 DEG C, while introducing 30000 seem of NH3 and 30 seem of TMGa into the reaction chamber; take Si as the doping element, and the doping concentration is 1E+16 atom / cm 3 , and grow a 300 nm current spreading layer on the N-type GaN layer.

[0068] S6: grow a multi-quantum well light emitting layer with a thickness of 0.15 μm on the current spreading layer, the multi-quantum well light emitting layer comprises alternately grown well layers and barrier layers, the well layers are InGaN, and the barrier layers are GaN, one cycle is formed by growing one well layer and one barrier layer, and the number of cycles is 10;

[0069] When growing the well layers, the temperature of the reaction chamber is set to 700 DEG C, while introducing 1200 seem of TMIn and 25 seem of TEGa into the reaction chamber; the doping concentration of In in each well layer is 1E+20 atom / cm 3 ; when growing the barrier layers, the temperature of the reaction chamber is set to 800 DEG C, while introducing 300 seem of TEGa into the reaction chamber; when growing the last barrier layer, TMAl is introduced into the reaction chamber, the flow rate of TMAl is linearly decreased from 180 seem to 0 seem, so that the mole number of Al in the last barrier layer is linearly decreased along the direction away from the substrate, and the ratio of the mole number of Al to the mole number of GaN is linearly decreased from 15% to 0%.

[0070] S7: set the temperature of the reaction chamber to 700 DEG C and the pressure to 800 mbar, while introducing 55000 seem of NH3, 25 seem of TMGa and 3600 seem of Cp2Mg into the reaction chamber, grow a low-temperature P-type GaN layer with a Mg doping concentration of 1.1E+16 atom / cm 3 and a thickness of 20 nm on the multi-quantum well light emitting layer.

[0071] S8: set the temperature of the reaction chamber to 700 DEG C, while introducing 30000 seem of NH3, 30 seem of TMGa and 150 seem of TMAl into the reaction chamber, the doping concentration of Al is 1E+17 atom / cm 3 , and grow a P-type AlGaN electron blocking layer with a thickness of 50 nm.

[0072] S9: set the temperature of the reaction chamber to 900 DEG C and the pressure to 1000 mbar, while introducing 40000 seem of NH3, 60000 seem of N2, 25 seem of TMGa and 300 seem of TMIn into the reaction chamber, grow an InGaN layer with a thickness of 10 nm on the P-type electron blocking layer.

[0073] S10: set the temperature of the reaction chamber to 900 DEG C and the pressure to 1000 mbar, and simultaneously introduce 60000 seem of NH3, 25 seem of TMGa and 2000 seem of Cp2Mg into the reaction chamber to grow a high-temperature P-type GaN layer with a thickness of 60 nm on the InGaN layer.

[0074] Embodiment 5 of the present application is a growth method of a high-reverse-voltage high-power LED epitaxial structure, comprising the following steps:

[0075] S1: place the substrate into the reaction chamber of a metal organic chemical vapor deposition device, and use H2 to purge the reaction chamber; then close the H2 purge, set the pressure of the reaction chamber to 600 mbar and the temperature to 1000 DEG C for 10 min; and then use H2 and NH3 to purge the reaction chamber.

[0076] S2: set the pressure of the reaction chamber to 200 mbar and the temperature to 800 DEG C, and simultaneously introduce 80 seem of TMGa and 45 seem of TMAl into the reaction chamber to grow a buffer layer with a thickness of 0.02 μm on the substrate.

[0077] S3: set the pressure of the reaction chamber to 500 mbar and the temperature to 900 DEG C, and simultaneously introduce 400 seem of TMGa into the reaction chamber to grow a U-shaped GaN layer on the buffer layer for 30 min.

[0078] S4: set the pressure of the reaction chamber to 1000 mbar, and use Si as the doping element with a doping concentration of 2E+19 atom / cm 3 grow a N-type GaN layer with a thickness of 3 μm on the U-shaped GaN layer.

[0079] S5: set the temperature of the reaction chamber to 950 DEG C, and simultaneously introduce 60000 seem of NH3 and 50 seem of TMGa into the reaction chamber; use Si as the doping element with a doping concentration of 2E+18 atom / cm 3 grow a current spreading layer with a thickness of 300 nm on the N-type GaN layer.

[0080] S6: grow a multiple quantum well light-emitting layer with a thickness of 0.2 μm on the current spreading layer, the multiple quantum well light-emitting layer comprising alternately grown well layers and barrier layers, the well layers being InGaN, and the barrier layers being GaN, one cycle being formed by growing one well layer and one barrier layer, and the number of cycles being 16;

[0081] when growing the well layers, set the temperature of the reaction chamber to 800 DEG C, and simultaneously introduce 1500 seem of TMIn and 400 seem of TEGa into the reaction chamber; the doping concentration of In in each well layer is 2E+20 atom / cm 3; when growing the last barrier layer, TMAl is introduced into the reaction chamber, the flow rate of TMAl is linearly decreased from 180sccm to 0sccm, so that the mole number of Al in the last barrier layer is linearly decreased along the direction away from the substrate, and the ratio of the mole number of Al to the mole number of GaN is linearly decreased from 15% to 0%.

[0082] S7: the temperature of the reaction chamber is set to 950℃, the pressure is 300mbar, 65000sccm of NH3, 50sccm of TMGa and 3600sccm of Cp2Mg are introduced into the reaction chamber, and a low-temperature P-type GaN layer with a Mg doping concentration of 5E+16atom / cm 3 and a thickness of 80nm is grown on the multi-quantum well light-emitting layer.

[0083] S8: the temperature of the reaction chamber is set to 950℃, 60000sccm of NH3, 50sccm of TMGa and 200sccm of TMAl are introduced into the reaction chamber, and a P-type AlGaN electron blocking layer with an Al doping concentration of 1E+18atom / cm 3 and a thickness of 70nm is grown.

[0084] S9: the temperature of the reaction chamber is set to 1050℃, the pressure is 600mbar, 30000sccm of NH3, 85000sccm of N2, 50sccm of TMGa and 600sccm of TMIn are introduced into the reaction chamber, and an InGaN layer with a thickness of 90nm is grown on the P-type electron blocking layer.

[0085] S10: the temperature of the reaction chamber is set to 1050℃, the pressure is 600mbar, 75000sccm of NH3, 50sccm of TMGa and 3000sccm of Cp2Mg are introduced into the reaction chamber, and a high-temperature P-type GaN layer with a thickness of 90nm is grown on the InGaN layer.

[0086] Please refer to Figure 1 Embodiment 6 of the present application is a high-reverse-voltage high-power LED epitaxial structure prepared by the growth method of embodiment 1, which comprises, from bottom to top, a substrate 1, a buffer layer 2, a U-shaped GaN layer 3, a N-type GaN layer 4, a current spreading layer 5, a multi-quantum well light-emitting layer 6, a low-temperature P-type GaN layer 7, an electron blocking layer 8, an InGaN layer 9 and a high-temperature P-type GaN layer 10.

[0087] Comparative Example 1 of the present application is:

[0088] The difference between Comparative Example 1 and Example 1 is only that: no InGaN layer is grown, and a high-temperature P-type GaN layer is directly grown on the electron blocking layer.

[0089] Comparative Example 2 of the present application is:

[0090] The difference between Comparative Example 2 and Example 1 is only that: no InGaN layer is grown, and a 95nm high-temperature P-type GaN layer is directly grown on the electron blocking layer.

[0091] Comparative Example 3 of the present application is:

[0092] The difference between Comparative Example 3 and Example 1 is only that: no InGaN layer is grown, and a 300nm high-temperature P-type GaN layer is directly grown on the electron blocking layer.

[0093] LED chips are prepared using the GaN-based epitaxial layers of Examples 1-3 and Comparative Examples 1-3 respectively (the specific steps are epitaxial wafer cleaning - >MESA - >CBL - >ITO - >MET - >PV - >electricity and alloy - >COW test - >grinding and thinning - >cracking - >sorting and full test), and the LED chips are made into 34*16mil blue light core particles. The LED chips are respectively subjected to reverse voltage VZ test, and the test results are shown in Table 1. Figure 2 The LED chips are respectively subjected to light efficiency test, and the test results are shown in Table 2. Figure 3

[0094] From Tables 1 and 2, it can be seen that: using a low-thickness high-temperature P-type GaN layer is difficult to fill the V-type defects, and the reverse voltage is low; using a high-thickness high-temperature P-type GaN layer can improve the reverse voltage, but will affect the light efficiency; the epitaxial wafer obtained by using the growth method of the present application can significantly improve the reverse voltage without affecting the light efficiency. Figure 2 3 In summary, the high-reverse-voltage high-power LED epitaxial structure and the growth method thereof provided by the present application have the following advantages:

[0095] (1) The InGaN interface processing layer is grown at the maximum opening of the V-type defects before the high-temperature P-type GaN layer on the electron blocking layer, and the InGaN is inclined to three-dimensional growth by using the relatively active characteristics of In element under a pure N2 atmosphere, so as to fill the V-type defects and improve the reverse voltage. At the same time, since the InGaN is inclined to three-dimensional growth, the required thickness is thin, and the influence on the light efficiency is reduced.

[0096] (1) The InGaN interface processing layer is grown at the maximum opening of the V-type defects before the high-temperature P-type GaN layer on the electron blocking layer, and the InGaN is inclined to three-dimensional growth by using the relatively active characteristics of In element under a pure N2 atmosphere, so as to fill the V-type defects and improve the reverse voltage. At the same time, since the InGaN is inclined to three-dimensional growth, the required thickness is thin, and the influence on the light efficiency is reduced. ​​

[0097] (2) Before growing buffer layer, remove the impurity gas in the reaction cavity, then pre-put the gas needed in the following reaction to pre-treat the substrate, which can improve the quality of the buffer layer.

[0098] (3) The application can improve the ESD performance and luminous efficiency of LED by doping Al which linearly decreases in the direction away from the substrate in the last barrier layer of the multi-quantum well light emitting layer.

[0099] (3) The LED can improve the luminous efficiency by growing low-temperature P-type GaN layer, electron blocking layer, InGaN layer and high-temperature P-type GaN layer in turn; the low-temperature P-type GaN layer can provide holes and protect the multi-quantum well active region from being damaged by high temperature; the high-temperature P-type GaN layer can reduce the working voltage of the LED, which can improve the performance and luminous efficiency of the LED to the greatest extent.

[0100] The above-mentioned is only the embodiment of the application, and does not limit the patent scope of the application, and any equivalent transformation or direct or indirect application in the related technical field by using the content of the specification and drawings of the application is also included in the patent protection scope of the application.

Claims

1. A method for growing a high-power LED epitaxial structure with high reverse voltage, characterized in that, Includes the following steps: A buffer layer, a U-type GaN layer, an N-type GaN layer, a multi-quantum-well active region layer, and a P-type GaN layer are sequentially grown on a substrate; the P-type GaN layer includes a low-temperature P-type GaN layer, an electron blocking layer, an InGaN layer, and a high-temperature P-type GaN layer grown sequentially. The InGaN layer is grown in a reaction chamber at a temperature of 900-1050°C and a pressure of 600-1000 mbar. Simultaneously, 30,000-60,000 sccm of NH3, 60,000-85,000 sccm of N2, 25-50 sccm of TMGa, and 200-600 sccm of TMIn are introduced into the reaction chamber. The thickness of the InGaN layer is 10~90nm.

2. The method for growing a high-power LED epitaxial structure with high reverse voltage according to claim 1, characterized in that, The electron blocking layer is a P-type AlGaN layer.

3. The method for growing a high-power LED epitaxial structure with high reverse voltage according to claim 1, characterized in that, The multi-quantum-well active region layer includes a current-spreading layer and a multi-quantum-well light-emitting layer grown sequentially.

4. The method for growing a high-power LED epitaxial structure with high reverse voltage according to claim 3, characterized in that, The current-spreading layer is grown in a reaction chamber at a temperature of 700–950°C, while 30,000–60,000 sccm of NH3 and 30–50 sccm of TMGa are simultaneously introduced into the chamber. Si is used as the dopant element, with a doping concentration of 1E+16–2E+18 atom / cm³. 3 .

5. The method for growing a high-power LED epitaxial structure with high reverse voltage according to claim 3, characterized in that, The multi-quantum-well light-emitting layer comprises alternately grown well layers and barrier layers. The well layers are InGaN and the barrier layers are GaN. Each growth of the well and barrier layers constitutes one cycle, and the number of cycles is 10 to 16.

6. The method for growing a high-power LED epitaxial structure with high reverse voltage according to claim 5, characterized in that, The growth of the multi-quantum-well light-emitting layer is carried out in the reaction chamber. During the growth of the last barrier layer, TMAl is introduced into the reaction chamber, and the flow rate of TMAl decreases linearly from 180 sccm to 0 sccm.

7. The method for growing a high-power LED epitaxial structure with high reverse voltage according to claim 3, characterized in that, The thickness of the multi-quantum-well light-emitting layer is 0.15~0.2μm.

8. A high-power LED epitaxial structure with high reverse voltage prepared by any of the growth methods described in claims 1-7.

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