Preparation method of flip green light epitaxial structure with high light efficiency and high ESD

Abstract

The application relates to the technical field of semiconductor photoelectric devices and semiconductor display manufacturing, and particularly relates to a preparation method of a high-light-efficiency high-ESD flip green light epitaxial structure. The preparation method comprises the following steps: sequentially growing an AlGaN / GaN buffer layer, a high-temperature non-doped UGaN layer, a high-temperature doped NGaN layer, an N-AlGaN layer, a multi-period Si-doped N-GaN layer, a superlattice InGaN / GaN stress release layer, a U-shaped electron deceleration layer, a multi-quantum well active region layer, a GaN / Aly1Ga1-y1N layer, a Mg-doped first p-GaN layer, a p-AlGaN layer and a second p-GaN layer on an AlN substrate; the U-shaped (non-Si-doped) electron deceleration layer is added between the stress release layer and the multi-quantum well active region layer, so that the internal quantum well light emitting efficiency and the ESD of the green light epitaxial structure are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor optoelectronic devices and semiconductor display manufacturing, and particularly relates to a preparation method of a high-light-efficiency high-ESD flip green epitaxial structure. BACKGROUND

[0002] A light-emitting diode (LED) releases energy to emit light through the recombination of electrons and holes, and converts electrical energy into light energy to realize the light emission of the light-emitting diode. With the continuous progress and development of science and technology, the light-emitting diode has been widely used in display and lighting. With the increasing demand of people for the display brightness, contrast and resolution of the light-emitting diode, the micro light-emitting diode (Micro LED) emerges as the times require. The micro light-emitting diode designs the light-emitting diode structure to be thin, small and arrayed, and reduces the pixel distance from millimeter level to micrometer level, which shows great advantages in brightness, contrast and reliability.

[0003] The main industry of the light-emitting diode field is to produce blue-green light-emitting diodes. Green light (blue-green light) light-emitting diode is an important component of three primary colors RGB, and the development and industrialization of green epitaxial technology will have great social and economic prospect value. A green epitaxial structure preparation method is disclosed in Chinese patent CN113270525A. The quantum well active region of the green epitaxial structure is a segmented growth GaN / In x1 Ga 1－x1 N / In X2 Ga 1－X2 N / GaN, which can improve the well-barrier mismatch, alleviate the Stark effect and improve the light-emitting efficiency of the light-emitting diode, but still cannot meet the demand of higher light efficiency and high ESD. A high hydrolysis-resistant blue-green LED epitaxial wafer structure and a preparation method thereof are disclosed in Chinese patent CN114551659A. A buffer layer, a u-GaN layer, a first n-GaN layer, an n-AlGaN layer, a second n-GaN layer, an InGaN / GaN layer, a quantum well layer, a first p-GaN layer, a p-AlGaN layer and a second p-GaN layer are grown on a substrate, and a blue-green LED epitaxial wafer is prepared. Although the high hydrolysis resistance is alleviated, the demand for high ESD (electrostatic discharge) and high reliability cannot be met. How to obtain a green light-emitting diode with high light-emitting efficiency and high ESD has become a difficult problem in the field. SUMMARY

[0004] In order to overcome the defects of the prior art, the technical problem to be solved by the present application is how to prepare a high-light-efficiency high-ESD flip green epitaxial structure.

[0005] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows: a preparation method of an inverted green light epitaxial structure with high light efficiency and high ESD, wherein an AlGaN / GaN buffer layer, a high-temperature non-doped UGaN layer, a high-temperature doped NGaN layer, an N-AlGaN layer, a multi-period Si-doped N-GaN layer, a superlattice InGaN / GaN stress release layer, a U-shaped electron deceleration layer, a multi-quantum well active region layer, a GaN / Aly1 Ga1-y1 N layer, a Mg-doped first p-GaN layer, a p-AlGaN layer and a second p-GaN layer are sequentially grown on an AlN substrate.

[0006] The U-shaped electron deceleration layer is a superlattice GaN / InGaN / GaN / AlGaN electron deceleration layer, and the U-shaped electron deceleration layer comprises 1-8 groups of GaN / InGaN / GaN / AlGaN stacks which are sequentially arranged by an InaGa1-aN potential well layer and an AlxGa1-xN potential barrier layer.

[0007] The present application has the advantages that: the present application provides a preparation method of a green light epitaxial structure, a U-shaped (non-Si-doped) electron deceleration layer is added between the stress release layer and the multi-quantum well active region layer, the electron moving speed is slowed down, the electron overflow is prevented, the electron distribution and transportation are effectively improved, the electron-hole recombination and light emission in the active region are increased, the internal quantum well light emission efficiency is improved, the small-current light efficiency is particularly improved, and the effect similar to a capacitor is achieved to improve the ESD of the green light epitaxial structure. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 Fig. 1 is a structural schematic diagram of an inverted green light epitaxial structure according to the present application;

[0009] Label explanation: 1, AlN substrate; 2, AlGaN / GaN buffer layer; 3, high-temperature non-doped UGaN layer; 4, high-temperature doped NGaN layer; 5, N-AlGaN layer; 6, multi-period Si-doped N-GaN layer; 7, superlattice InGaN / GaN stress release layer; 8, U-shaped electron deceleration layer; 9, multi-quantum well active region layer; 10, GaN / Al y1 Ga 1－y1 N layer; 11, Mg-doped first p-GaN layer; 12, p-AlGaN layer; 13, second p-GaN layer. DETAILED DESCRIPTION

[0010] In order to describe the technical content, purposes and effects of the present application in detail, the following will be described in combination with the embodiments and the accompanying drawings.

[0011] The most critical concept of the present application is that: by adding a layer U-shaped (undoped Si) electron deceleration layer between the stress release layer and the multi-quantum well active region layer, the internal quantum well light emitting efficiency and the ESD of the green light epitaxial structure are improved.

[0012] Please refer to Figure 1 The preparation method of the high light efficiency and high ESD flip-chip green light epitaxial structure of the present application is that: on an AlN substrate, an AlGaN / GaN buffer layer, a high-temperature undoped UGaN layer, a high-temperature doped NGaN layer, an N-AlGaN layer, a multi-period Si-doped N-GaN layer, a superlattice InGaN / GaN stress release layer, a U-shaped electron deceleration layer, a multi-quantum well active region layer, a GaN / Al y1 Ga 1－y1 N layer, a Mg-doped first p-GaN layer, a p-AlGaN layer and a second p-GaN layer are sequentially grown.

[0013] The U-shaped electron deceleration layer is a superlattice GaN / InGaN / GaN / AlGaN electron deceleration layer, and the U-shaped electron deceleration layer includes 1-8 groups of GaN / InGaN / GaN / AlGaN stacks which are stacked by In a Ga 1-a N well layers and Al x Ga 1-x N barrier layers.

[0014] Preferably, the U-shaped electron deceleration layer includes 3-5 groups of GaN / InGaN / GaN / AlGaN stacks which are stacked by In a Ga 1-a N well layers and Al x Ga 1-x N barrier layers.

[0015] As can be seen from the above description, the present application provides a preparation method of a green light epitaxial structure, by adding a layer U-shaped (undoped Si) electron deceleration layer between the stress release layer and the multi-quantum well active region layer, the electron moving speed is slowed down, the electron overflow is prevented, the distribution and transportation of the electron are effectively improved, the electron-hole recombination and light emission in the active region are increased, the internal quantum well light emitting efficiency is improved, the small current light efficiency is particularly improved, and the effect similar to a capacitor is achieved to improve the ESD of the green light epitaxial structure.

[0016] The preparation method of the high light efficiency and high ESD flip-chip green light epitaxial structure of the present application is that: on an AlN substrate, an AlGaN / GaN buffer layer, a high-temperature undoped UGaN layer, a high-temperature doped NGaN layer, an N-AlGaN layer, a multi-period Si-doped N-GaN layer, a superlattice InGaN / GaN stress release layer, a U-shaped electron deceleration layer, a multi-quantum well active region layer, a GaN / Al y1 Ga 1－y1N layer, Mg doped first p-GaN layer, p-AlGaN layer and second p-GaN layer, obtaining high light efficiency and high ESD flip green epitaxial structure; wherein high temperature doped type N-GaN layer, N-AlGaN layer and multi-period Si doped N-GaN layer cooperate, Mg doped first p-GaN layer, p-AlGaN layer and second p-GaN layer cooperate to effectively block defects; multi-quantum well active region layer can reduce well barrier mismatch, alleviate the Stark effect, reduce dislocation, improve light emitting efficiency and improve growth yield; multi-period Si doped N-GaN layer can reduce stress; superlattice InGaN / GaN stress release layer reduces dislocation and stress generated by N layer growth; GaN / Al y1 Ga 1－y1 N layer inhibits electron overflow; Mg doped first p-GaN layer, p-AlGaN layer and second p-GaN layer ensure good ohmic contact with the reflective layer and the electrode.

[0017] Further, In a Ga 1-a N potential well layer is 1-5nm thick, Al x Ga 1-x N potential barrier layer is 2-15nm thick, Al x Ga 1-x N potential barrier layer has an Al doping concentration of 5x10 18 -1x10 19 cm -3 .

[0018] Preferably, In a Ga 1-a N potential well layer is 1-3nm thick, Al x Ga 1-x N potential barrier layer is 5-10nm thick.

[0019] From the above description, the thickness of In a Ga 1-a N potential well layer and Al x Ga 1-x N potential barrier layer: if the thickness is thick, the number of cycles is less, and vice versa. The more the layers are stacked, the better the light efficiency is.

[0020] Further, the growth of the U-shaped electron deceleration layer is carried out in a reaction chamber, the temperature of the reaction chamber is 850-950℃, the well-barricade temperature difference is 80-120℃, the pressure of the reaction chamber is 150-200 Tor, the rotation speed is 600 revolutions / minute, H2 carrier gas is used, and the V / Ⅲ molar ratio is 1000-5000.

[0021] Further, the thickness of the second p-GaN layer is 5-50nm.

[0022] Preferably, the thickness of the second p-GaN layer is 10-20 nm.

[0023] As can be seen from the above description, the U-shaped (un-doped Si) electron deceleration layer is added between the stress release layer and the multi-quantum well active region layer, the internal quantum well light emitting efficiency of the epitaxial structure is improved, the second p-GaN layer is thinned, and the external quantum well light emitting efficiency is improved, and the combination of the two greatly improves the light emitting efficiency of the epitaxial structure.

[0024] Further, the growth of the AlGaN / GaN buffer layer is carried out in a reaction cavity, the temperature of the reaction cavity is 700-900℃, the pressure of the reaction cavity is 100-300 Tor, the rotation speed is 800-1200 revolutions / minute, H2 carrier gas is used, and the V / III molar ratio is 60-100.

[0025] As can be seen from the above description, the AlGaN / GaN buffer layer is more suitable for the subsequent GaN lattice growth than the conventional low-temperature AlGaN buffer layer, which is beneficial to the warping adjustment and stress release.

[0026] Further, the growth of the high-temperature undoped UGaN layer is carried out in a reaction cavity, the temperature of the reaction cavity is 1050-1100℃, the pressure of the reaction cavity is 150-300 Tor, the rotation speed is 800-1200 revolutions / minute, H2 carrier gas is used, and the V / III molar ratio is 100-300.

[0027] Further, the thickness of the high-temperature undoped UGaN layer is 1-3 μm.

[0028] Further, the growth of the high-temperature doped NGaN layer is carried out in a reaction cavity, the temperature of the reaction cavity is 1000-1040℃, the pressure of the reaction cavity is 150-300 Tor, the rotation speed is 800-1200 revolutions / minute, H2 carrier gas is used, and the V / III molar ratio is 100-300.

[0029] Further, the thickness of the high-temperature doped NGaN layer is 0.5-2 μm.

[0030] Further, the growth of the N-AlGaN layer is carried out in a reaction cavity, the temperature of the reaction cavity is 900-1000℃.

[0031] Further, the thickness of the N-AlGaN layer is 10-100 nm.

[0032] Further, the growth of the multi-period Si-doped N-GaN layer is carried out in a reaction cavity, the temperature of the reaction cavity is 1000-1050℃, the pressure of the reaction cavity is 150-200 Tor, the rotation speed is 1100 revolutions / minute, H2 carrier gas is used, and the V / III molar ratio is 100-300.

[0033] Further, the thickness of the multi-period Si-doped N-GaN layer is 1.5-2 μm.

[0034] As can be seen from the above description, the periodic growth of the multi-period Si-doped GaN can reduce stress.

[0035] Further, the growth of the superlattice InGaN / GaN stress release layer is performed in a reaction chamber, the temperature of the reaction chamber is 800-900 °C, the pressure of the reaction chamber is 150-200 Tor, the rotation speed is 650 rpm, H2 carrier gas is used, and the V / III molar ratio is 2000-4000.

[0036] As can be seen from the above description, the superlattice InGaN / GaN can reduce dislocations and stress generated by the growth of the N layer.

[0037] Further, the growth of the multi-quantum well active region layer is performed in a reaction chamber, the temperature of the reaction chamber is 900-1000 °C, the well-barrier temperature difference is 100-150 °C, the pressure of the reaction chamber is 250 Tor, the rotation speed is 600 rpm, and H2 carrier gas is used.

[0038] As can be seen from the above description, the multi-quantum well active region layer adopts GaN / In x1 Ga 1－x1 N / In x2 Ga 1－x2 N / GaN, GaN / Al y1 Ga 1－y1 N different In component structures, the content of x1 and the content of x2 are adjusted by temperature, the well-barrier mismatch is reduced, and thus the Stark effect is relieved; the quantum barrier adopts Si-doped GaN, which can reduce dislocations; the light efficiency is improved, and the growth yield is improved.

[0039] As can be seen from the above description, the multi-quantum well active region layer adopts GaN / In y1 Ga 1－y1 N, which can reduce dislocations and improve the light efficiency.

[0040] Further, the growth of the GaN / Al y1 Ga 1－y1 N layer is performed in a reaction chamber, the temperature of the reaction chamber is 950-1000 °C, the pressure of the reaction chamber is 200 Tor, the rotation speed is 600 rpm, and H2 carrier gas is used.

[0041] As can be seen from the above description, the GaN / Al y1 Ga 1－y1 N layer can suppress electron overflow.

[0042] Further, the growth of the Mg-doped first p-GaN layer is performed in a reaction chamber, the temperature of the reaction chamber is 760-780 °C, the pressure of the reaction chamber is 250 Tor, the rotation speed is 600 rpm, H2 carrier gas is used, and the doping concentration is 5×10 19 -1.5×10 20 cm-3 .

[0043] Further, the p-AlGaN layer is grown in a reaction chamber with a temperature of 950-1000℃, a pressure of 100-150 Torr, a rotation speed of 1000 rpm, and H2 carrier gas.

[0044] Further, the p-AlGaN layer has a thickness of 10-100 nm, a Mg doping concentration of 1×1018-2×1019 cm-3, and an Al doping concentration of 1×1018-1×1019 cm-3. 18 20 -3 19 21 -3 .

[0045] Further, the second p-GaN layer is grown in a reaction chamber with a temperature of 800-900℃, a doping concentration of 1×1018-1×1019 cm-3. 18 20 -3 .

[0046] Please refer to FIG. 1, an embodiment of the present application is as follows: Figure 1

[0047] A preparation method of a high-efficiency high-ESD flip green light epitaxial structure, comprising the following steps:

[0048] S1: placing an AlN substrate 1 in a reaction chamber;

[0049] S2: setting a temperature of 700℃, a pressure of 100 Torr, a rotation speed of 800 rpm, using H2 carrier gas, and a V / III molar ratio of 60, and growing an AlGaN / GaN buffer layer 2;

[0050] S3: setting a temperature of 1050℃, a pressure of 150 Torr, a rotation speed of 800 rpm, using H2 carrier gas, and a V / III molar ratio of 100, and growing a high-temperature undoped UGaN layer 3 with a thickness of 1 μm;

[0051] S4: setting a temperature of 1000℃, a pressure of 150 Torr, a rotation speed of 800 rpm, using H2 carrier gas, and a V / III molar ratio of 100, and growing a high-temperature doped NGaN layer 4 with a thickness of 0.5 μm;

[0052] S5: setting a temperature of 900℃, and growing an N-AlGaN layer 5 with a thickness of 10 nm;

[0053] ​​​​​​​​S6: set temperature to 1000℃, pressure to 150 Tor, rotation speed to 1100 rpm, use H2carrier gas, V / III molar ratio to 100, grow multi-period Si-doped N-GaN layer 6 with thickness of 1.5-2 μm;

[0054] S7: set temperature to 800℃, pressure to 150 Tor, rotation speed to 650 rpm, use H2carrier gas, V / III molar ratio to 2000, grow superlattice InGaN / GaN stress release layer 7.

[0055] S8: set temperature to 850℃, well / barrier temperature difference to 80℃, pressure to 200 Tor, rotation speed to 600 rpm, use H2carrier gas, V / III molar ratio to 1000, grow U-shaped electron deceleration layer 8.

[0056] U-shaped electron deceleration layer 8 is a superlattice GaN / InGaN / GaN / AlGaN electron deceleration layer, and the U-shaped electron deceleration layer comprises three groups of GaN InGaN GaN AlGaN layers stacked together. a Ga 1-a N well layers and Al x Ga 1-x N barrier layers, the In a Ga 1-a N well layer has a thickness of 1 nm, the Al x Ga 1-x N barrier layer has a thickness of 5 nm, and the Al x Ga 1-x N barrier layer has an Al doping concentration of 5×10 18 cm -3 -19.

[0057] S9: set temperature to 900℃, well / barrier temperature difference to 100℃, pressure to 250 Tor, rotation speed to 600 rpm, use H2carrier gas, grow multi-quantum well active region layer 9, and the multi-quantum well active region layer 9 adopts GaN / In x1 Ga 1－x1 N / In x2 Ga 1－x2 N / GaN, GaN / Al y1 Ga 1－y1 N different In component structures.

[0058] S10: set temperature to 950℃, pressure to 200 Tor, rotation speed to 600 rpm, use H2carrier gas, grow GaN / Al y1 Ga 1－y1 N layer 10.

[0059] S11: set temperature to 760℃, pressure to 250 Tor, rotation speed to 600 rpm, use H2 carrier gas, grow Mg-doped first p-GaN layer 11 with a doping concentration of 5x1018 cm-3; 19 -3 cm-3;

[0060] S12: set temperature to 950℃, pressure to 100 Tor, rotation speed to 1000 rpm, use H2 carrier gas, grow p-AlGaN layer 12 with a thickness of 10 nm, Mg-doped concentration of 1x1018 cm-3, and Al-doped concentration of 1x1018 cm-3; 18 -3 19 -3 cm-3;

[0061] S13: set temperature to 800℃, grow second p-GaN layer 13 with a thickness of 5 nm and a doping concentration of 1x1018 cm-3. 18 -3 .

[0062] Embodiment two of the present application is:

[0063] A preparation method of a high-efficiency high-ESD flip green light epitaxial structure, comprising the following steps:

[0064] S1: place an AlN substrate in a reaction cavity;

[0065] S2: set temperature to 900℃, pressure to 300 Tor, rotation speed to 1200 rpm, use H2 carrier gas, V / III molar ratio to 100, grow AlGaN / GaN buffer layer;

[0066] S3: set temperature to 1100℃, pressure to 300 Tor, rotation speed to 1200 rpm, use H2 carrier gas, V / III molar ratio to 300, grow high-temperature undoped UGaN layer with a thickness of 3 μm;

[0067] S4: set temperature to 1040℃, pressure to 300 Tor, rotation speed to 1200 rpm, use H2 carrier gas, V / III molar ratio to 300, grow high-temperature doped NGaN layer with a thickness of 2 μm;

[0068] S5: set temperature to 1000℃, grow N-AlGaN layer with a thickness of 100 nm;

[0069] S6: set temperature to 1050℃, pressure to 200 Tor, rotation speed to 1100 rpm, use H2 carrier gas, V / III molar ratio to 300, grow multi-period Si-doped N-GaN layer with a thickness of 2 μm;

[0070] ​​​​​S7: Set the temperature to 900℃, the pressure to 200 Tor, the rotation speed to 650 rpm, use H2 carrier gas, and the V / III molar ratio to 4000 to grow a superlattice InGaN / GaN stress-relief layer.

[0071] S8: Set temperature to 950℃, well-barrier temperature difference to 100℃, pressure to 200 Tor, rotation speed to 600 rpm, use H2 carrier gas, V / III molar ratio to 5000, grow U-shaped electron deceleration layer;

[0072] The U-shaped electron deceleration layer is a superlattice GaN / InGaN / GaN / AlGaN electron deceleration layer. The U-shaped electron deceleration layer includes 5 groups of In a Ga 1-a N-well layer and Al x Ga 1-x A GaN / InGaN / GaN / AlGaN stack formed by stacking N-type barrier layers, In a Ga 1-a The thickness of the N-potential well layer is 3 nm, Al x Ga 1-x The thickness of the N-barrier layer is 7 nm, Al x Ga 1-x The Al doping concentration of the N-barrier layer is 1×10⁻⁶. 19 cm -3 ;

[0073] S9: The set temperature is 1000℃, the well-barrier temperature difference is 150℃, the pressure is 250 Tor, the rotation speed is 600 rpm, H2 carrier gas is used, and a multi-quantum-well active region layer is grown. The multi-quantum-well active region layer adopts GaN / In. x1 Ga 1－x1 N / In x2 Ga 1－x2 N / GaN, GaN / Al y1 Ga 1－y1 Different In component structures;

[0074] The S10 system is set at a temperature of 1000℃, a pressure of 200 Tor, and a rotation speed of 600 rpm, using H2 carrier gas to grow GaN / Al. y1 Ga 1－y1 N layers;

[0075] S11: Set temperature to 780℃, pressure to 250 Tor, rotation speed to 600 rpm, using H2 carrier gas, growth doping concentration to 1.5 × 10⁻⁶. 20 cm -3 The first p-GaN layer is doped with Mg.

[0076] S12: set temperature to 1000 DEG C, pressure to 150 Tor, rotation speed to 1000 rpm, use H2 carrier gas, grow p-AlGaN layer with thickness of 100 nm, Mg doping concentration of p-AlGaN layer is 2*10 20 cm -3 -1, Al doping concentration is 1*10 21 cm -3 -1;

[0077] S13: set temperature to 900 DEG C, grow second p-GaN layer with thickness of 50 nm, doping concentration of second p-GaN layer is 1*10 20 cm -3 -1.

[0078] Embodiment three of the application is:

[0079] A preparation method of a high-efficiency high-ESD flip green light epitaxial structure, comprising the following steps:

[0080] S1: place AlN substrate in reaction cavity;

[0081] S2: set temperature to 800 DEG C, pressure to 200 Tor, rotation speed to 1000 rpm, use H2 carrier gas, V / III molar ratio to 80, grow AlGaN / GaN buffer layer;

[0082] S3: set temperature to 1000 DEG C, pressure to 200 Tor, rotation speed to 900 rpm, use H2 carrier gas, V / III molar ratio to 200, grow high-temperature undoped UGaN layer with thickness of 2 microns;

[0083] S4: set temperature to 1020 DEG C, pressure to 200 Tor, rotation speed to 1100 rpm, use H2 carrier gas, V / III molar ratio to 200, grow high-temperature doped NGaN layer with thickness of 1.5 microns;

[0084] S5: set temperature to 1050 DEG C, grow N-AlGaN layer with thickness of 20 nm;

[0085] S6: set temperature to 1020 DEG C, pressure to 1700 Tor, rotation speed to 1100 rpm, use H2 carrier gas, V / III molar ratio to 200, grow multi-period Si-doped N-GaN layer with thickness of 1.7 microns;

[0086] S7: set temperature to 850 DEG C, pressure to 160 Tor, rotation speed to 650 rpm, use H2 carrier gas, V / III molar ratio to 3000, grow superlattice InGaN / GaN stress release layer.

[0087] S8: set temperature to 900℃, well-barrier temperature difference to 120℃, pressure to 180 Tor, rotation speed to 600 rpm, use H2 carrier gas, V / III molar ratio to 2000, grow U-shaped electron deceleration layer;

[0088] The U-shaped electron deceleration layer is a superlattice GaN / InGaN / GaN / AlGaN electron deceleration layer, and the U-shaped electron deceleration layer comprises 8 groups of GaN / InGaN / GaN / AlGaN stacks arranged in a stack manner, wherein each group of GaN / InGaN / GaN / AlGaN stack comprises a GaN well layer, an InGaN barrier layer, a GaN well layer, and an AlGaN barrier layer. a Ga 1-a N well layer and an Al x Ga 1-x N barrier layer, and the thickness of the In a Ga 1-a N well layer is 5 nm, the thickness of the Al x Ga 1-x N barrier layer is 10 nm, the Al doping concentration of the Al x Ga 1-x N barrier layer is 5×10 19 cm -3 .

[0089] S9: set temperature to 1050℃, well-barrier temperature difference to 130℃, pressure to 250 Tor, rotation speed to 600 rpm, use H2 carrier gas, grow multi-quantum well active region layer, and the multi-quantum well active region layer adopts GaN / In x1 Ga 1－x1 N / In x2 Ga 1－x2 N / GaN, GaN / Al y1 Ga 1－y1 N different In component structures.

[0090] S10: set temperature to 970℃, pressure to 200 Tor, rotation speed to 600 rpm, use H2 carrier gas, and grow GaN / Al y1 Ga 1－y1 N layer.

[0091] S11: set temperature to 770℃, pressure to 250 Tor, rotation speed to 600 rpm, use H2 carrier gas, and grow Mg-doped first p-GaN layer with a doping concentration of 1×10 20 cm -3 .

[0092] S12: set temperature to 970℃, pressure to 130 Tor, rotation speed to 1000 rpm, use H2 carrier gas, grow p-AlGaN layer with a thickness of 30 nm, and the Mg doping concentration of the p-AlGaN layer is 1×10 20 cm -3 , and the Al doping concentration is 1×1020 cm -3 ;

[0093] S13: set the temperature to 870℃, grow a second p-GaN layer with a thickness of 10 nm, and the doping concentration of the second p-GaN layer is 1×1018cm-3. 19 cm -3 .

[0094] The comparative example one of the present application is:

[0095] The comparative example one and the example three are different in that: the U-shaped electron deceleration layer is not contained.

[0096] The comparative example two of the present application is:

[0097] The comparative example two and the example three are different in that: the U-shaped electron deceleration layer is between the multi-period Si-doped N-GaN layer and the stress release layer.

[0098] The comparative example three of the present application is:

[0099] The comparative example three and the example three are different in that: the thickness of the second p-GaN is 100 nm.

[0100] The LED chips are prepared by using the high light efficiency and high ESD flip green light epitaxial structure of the example three and the comparative examples one to three (the specific steps are epitaxial wafer cleaning -> MESA -> CBL -> ITO -> MET -> PV -> electrical and alloy -> COW test -> grinding and thinning -> cleavage -> sorting and full test), and the LED chips are made into 3*6 mil blue light core particles, and the light emitting efficiency and ESD of the core particles are tested, and the test results are shown in Table 1.

[0101] Table 1

[0102]

[0103] In summary, the preparation method of the green light epitaxial structure provided by the present application adds a layer of U-shaped (without Si-doped) electron deceleration layer between the stress release layer and the multi-quantum well active region layer, slows down the electron moving speed, prevents electron overflow, effectively improves the distribution and transportation of electrons, increases the recombination and light emission of electron holes in the active region, improves the internal quantum well light emitting efficiency, especially improves the small current light efficiency, and at the same time plays a similar capacitor effect to improve the ESD of the green light epitaxial structure; the second p-GaN layer is thinned to improve the external quantum well light emitting efficiency, and the combination of the two greatly improves the light emitting efficiency of the epitaxial structure.

[0104] The application grows AlGaN / GaN buffer layer, high-temperature non-doped UGaN layer, high-temperature doped NGaN layer, N-AlGaN layer, multi-period Si-doped N-GaN layer, superlattice InGaN / GaN stress release layer, U-shaped electron deceleration layer, multi-quantum well active region layer, GaN / Al y1 Ga 1－y1 N layer, Mg-doped first p-GaN layer, p-AlGaN layer and second p-GaN layer on AlN substrate in sequence, to obtain an inverted green light epitaxial structure with high light efficiency and ESD; wherein the high-temperature doped NGaN layer, N-AlGaN layer and multi-period Si-doped N-GaN layer cooperate, and the Mg-doped first p-GaN layer, p-AlGaN layer and second p-GaN layer cooperate to effectively block defects; the multi-quantum well active region layer can reduce well-barrier mismatch, relieve Stark effect, reduce dislocation, improve light-emitting efficiency and increase growth yield; the multi-period Si-doped N-GaN layer can reduce stress; the superlattice InGaN / GaN stress release layer reduces dislocation and stress generated by N layer growth; the GaN / Al y1 Ga 1－y1 N layer inhibits electron overflow; and the Mg-doped first p-GaN layer, p-AlGaN layer and second p-GaN layer ensure good ohmic contact with the reflective layer and the electrode.

[0105] The above description is only an embodiment of the application, and does not limit the patent scope of the application, and any equivalent transformation or direct or indirect application in related technical fields using the content of the specification and drawings is also included in the patent protection scope of the application.

Claims

1. A method for fabricating a high-efficiency, high-ESD flip-chip green epitaxial structure, characterized in that, On an AlN substrate, the following layers are sequentially grown: AlGaN / GaN buffer layer, high-temperature undoped UGaN layer, high-temperature doped NGaN layer, N-AlGaN layer, multi-period Si-doped N-GaN layer, superlattice InGaN / GaN stress relief layer, U-shaped electron deceleration layer, multi-quantum well active region layer, and GaN / Al y1 Ga 1－y1 N-layer, Mg-doped first p-GaN layer, p-AlGaN layer and second p-GaN layer; The U-shaped electron deceleration layer is a superlattice GaN / InGaN / GaN / AlGaN electron deceleration layer, comprising 1 to 8 groups of In a Ga 1-a N-well layer and Al x Ga 1-x A superlattice GaN / InGaN / GaN / AlGaN stack formed by stacking N-barrier layers.

2. The method for fabricating a high-efficiency, high-ESD flip-chip green epitaxial structure according to claim 1, characterized in that, The In a Ga 1-a The thickness of the N-potential well layer is 1~5nm, and the Al x Ga 1-x The thickness of the N-barrier layer is 2~15nm, and the Al x Ga 1-x The Al doping concentration of the N-barrier layer is 5 × 10⁻⁶. 18 ~1×10 19 cm -3 .

3. The method for fabricating a high-efficiency, high-ESD flip-chip green epitaxial structure according to claim 1, characterized in that, The growth of the U-shaped electron deceleration layer is carried out in a reaction chamber with a temperature of 850~950℃, a trap-barrier temperature difference of 80~120℃, a pressure of 150~200 Torr, a rotation speed of 600 rpm, H2 carrier gas, and a V / III molar ratio of 1000~5000.

4. The method for fabricating a high-efficiency, high-ESD flip-chip green epitaxial structure according to claim 1, characterized in that, The thickness of the second p-GaN layer is 5~50nm.

5. The method for fabricating a high-efficiency, high-ESD flip-chip green epitaxial structure according to claim 1, characterized in that, The growth of the AlGaN / GaN buffer layer is carried out in a reaction chamber at a temperature of 700-900°C, a pressure of 100-300 Torr, a rotation speed of 800-1200 rpm, using H2 carrier gas, and a V / III molar ratio of 60-100.

6. The method for fabricating a high-efficiency, high-ESD flip-chip green epitaxial structure according to claim 1, characterized in that, The high-temperature undoped UGaN layer is grown in a reaction chamber at a temperature of 1050-1100°C, a pressure of 150-300 Torr, a rotation speed of 800-1200 rpm, using H2 as the carrier gas, and a V / III molar ratio of 100-300.

7. The method for fabricating a high-efficiency, high-ESD flip-chip green epitaxial structure according to claim 1, characterized in that, The high-temperature doped NGaN layer is grown in a reaction chamber at a temperature of 1000-1040°C, a pressure of 150-300 Torr, a rotation speed of 800-1200 rpm, and H2 carrier gas with a V / III molar ratio of 100-300.

8. The method for fabricating a high-efficiency, high-ESD flip-chip green epitaxial structure according to claim 1, characterized in that, The growth of the multi-period Si-doped N-GaN layer is carried out in a reaction chamber at a temperature of 1000~1050℃, a pressure of 150~200 Torr, a rotation speed of 1100 rpm, using H2 as the carrier gas, and a V / III molar ratio of 100~300.

9. The method for fabricating a high-efficiency, high-ESD flip-chip green epitaxial structure according to claim 1, characterized in that, The superlattice InGaN / GaN stress-relief layer is grown in a reaction chamber at a temperature of 800-900°C, a pressure of 150-200 Torr, a rotation speed of 650 rpm, and H2 carrier gas with a V / III molar ratio of 2000-4000.

10. The method for fabricating a high-efficiency, high-ESD flip-chip green epitaxial structure according to claim 1, characterized in that, The growth of the multi-quantum well active region layer is carried out in a reaction chamber with a temperature of 900~1000℃, a well-barrier temperature difference of 100~150℃, a pressure of 250 Torr, a rotation speed of 600 rpm, and H2 carrier gas.

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