A high-efficiency light-emitting diode epitaxial wafer and preparation method thereof

Abstract

The present invention provides a high-efficiency light-emitting diode epitaxial wafer and a preparation method thereof. The light-emitting diode epitaxial wafer comprises a substrate, and a buffer layer, a non-doped GaN layer, an N-type GaN layer, an N-type electron blocking layer, a multi-quantum well layer, an electron blocking layer and a P-type GaN layer sequentially deposited on the substrate; the N-type electron blocking layer comprises a SiN layer, an AlN layer, and a P-type GaN layer sequentially deposited on the N-type GaN layer. a Si 1‑a N layer and super lattice layer, the super lattice layer includes Si doped Al deposited alternately in a preset period b Ga 1‑b N layer and non-doped Al x In y Ga 1‑x‑y N layer. The present invention inserts an N-type electron blocking layer between the N-type GaN layer and the multi-quantum well layer to reduce the movement speed of electrons, effectively reducing the number of electrons in the N-type GaN layer rushing through the multi-quantum well layer to reach the P-type GaN layer and non-radiative recombination with holes, thereby improving the radiative recombination efficiency of electrons and holes in the quantum well layer.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic technology, and in particular to a high-efficiency light-emitting diode epitaxial wafer and a preparation method thereof. Background Art

[0002] In recent years, with the continuous advancement of science and technology, the achievements in semiconductor materials have become increasingly obvious, especially nitride semiconductor materials such as GaN, AlN, InN, and their alloy compounds, which have developed rapidly.

[0003] Among numerous semiconductor materials, GaN, as a representative of compound semiconductors, is attracting increasing attention for its numerous advantages, including energy conservation and environmental protection, compact size, long lifespan, fast lighting response time, and color tunability. N-type doping is essential for the fabrication of semiconductor devices. Doping GaN with Si effectively achieves n-type doping, generating sufficient electrons to enter the quantum wells and recombine with holes.

[0004] Although doping Si into GaN materials can generate enough electrons, the transfer speed of electrons in semiconductors is much higher than the transfer speed of holes in semiconductors. Therefore, the electrons in the Si-doped N-type GaN layer will pass through the multi-quantum well layer and reach the P-type GaN layer, and undergo non-radiative recombination with the holes in the P-type GaN layer, thereby reducing the luminous efficiency of the light-emitting diode. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a high-efficiency light-emitting diode epitaxial wafer and a preparation method to solve the problem in the prior art that the N-type GaN transfer speed is too fast and it is easy to non-radiatively recombine with holes in the P-type GaN layer.

[0006] The first aspect of the present invention provides a high-efficiency light-emitting diode epitaxial wafer, comprising a substrate, and a buffer layer, an undoped GaN layer, an N-type GaN layer, an N-type electron blocking layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer sequentially deposited on the substrate; the N-type electron blocking layer comprises a SiN layer, an AlN layer, and a P-type GaN layer sequentially deposited on the N-type GaN layer. a Si 1-a N layer and super lattice layer, wherein the super lattice layer comprises Si doped Al deposited alternately in a preset period. b Ga 1-b N layer and non-doped Al x In y Ga 1-x- y N layers.

[0007] The beneficial effects of the present invention are as follows: the present invention provides a high-efficiency light-emitting diode epitaxial wafer, wherein an N-type electron blocking layer is inserted between the N-type GaN layer and the multi-quantum well layer, wherein the electron blocking layer comprises a SiN layer, an Al layer, and a SiN layer sequentially deposited on the N-type GaN layer. a Si 1-a N layer and super lattice layer, the super lattice layer includes Si doped Al deposited alternately in a preset period b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y N layer; Due to the defects of the substrate, heterogeneous defects will be generated during epitaxial growth, and dislocations are easily generated along the growth direction of the epitaxial layer. The Si doped in the N-type GaN layer is easy to gather along the dislocations, resulting in leakage. Therefore, the SiN layer and Al2O3 layer are deposited on the N-type GaN layer. a Si 1-a N layer, so that a dense SiN layer and Al a Si 1-a The N-layer film can effectively prevent dislocations from extending to the epitaxial layer, reduce heterogeneous defects, and further reduce the accumulation of Si doping on dislocations, thus preventing leakage. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The superlattice structure formed by the N layer forms a barrier layer and a potential well layer, which makes the energy band of the superlattice layer change. b Ga 1-b In the N layer, due to its higher potential barrier, the electron flow rate is reduced. x In y Ga 1-x-y Since the In atomic radius in the N layer is large, it has a clay effect, which keeps the electrons in the potential well layer. Therefore, through the periodic alternation of the barrier layer / potential well layer, the electrons in the N-type GaN layer are effectively reduced from rushing through the multi-quantum well layer to reach the P-type GaN layer to undergo non-radiative recombination with holes, thereby improving the radiative recombination efficiency of electrons and holes in the quantum well layer.

[0008] Preferably, in the Al a Si 1-a The Al content in the N layer gradually increases along the growth direction of the epitaxial wafer, and the value of a is 0.01-1.

[0009] Preferably, the Si doped with Al b Ga 1-b The value of b in the N layer is 0-0.5.

[0010] Preferably, the Si doped with Alb Ga 1-b The concentration of Si doping in the N layer is 1*10 16 atoms / cm 3 -1*10 18 atoms / cm 3 .

[0011] Preferably, the non-doped Al x In y Ga 1-x-y In the N layer, the value of x is 0-0.1, and the value of y is 0-0.1.

[0012] Preferably, the thickness of the SiN layer is 1nm-100nm, and the Al a Si 1-a The thickness of the N layer is 1nm-100nm, and the Si doped with Al b Ga 1-b The thickness of the N layer is 1nm-50nm, and the non-doped Al x In y Ga 1-x-y The thickness of the N layer is 1nm-10nm.

[0013] Preferably, the preset period is 1-20.

[0014] Another aspect of the present invention provides a method for preparing the above-mentioned high-efficiency light-emitting diode epitaxial wafer, comprising the following steps:

[0015] providing a substrate;

[0016] Depositing a buffer layer, an undoped GaN layer, an N-type GaN layer, an N-type electron blocking layer, a multi-quantum well layer, an electron blocking layer and a P-type GaN layer in sequence on the substrate;

[0017] Wherein, the N-type electron blocking layer comprises a SiN layer, an Al a Si 1-a N layer and super lattice layer, wherein the super lattice layer comprises Si doped Al deposited alternately in a preset period. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y N layers.

[0018] Preferably, the growth atmosphere during the growth of the N-type electron blocking layer is a mixed gas with an N2 / NH3 composition ratio of 1:5-5:1.

[0019] Preferably, the growth pressure during the growth of the N-type electron blocking layer is 50 torr-300 torr; the SiN layer and the Al a Si 1-a The deposition growth temperature of the N layer is 900° C.-1100° C., and the deposition growth temperature of the superlattice layer is 800° C.-1000° C.

[0020] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure of a high-efficiency light-emitting diode epitaxial wafer provided by the present invention;

[0022] Figure 2 This is a flow chart of the method for preparing a high-efficiency light-emitting diode epitaxial wafer provided by the present invention.

[0023] Description of main component symbols:

[0024] substrate 10 buffer layer 20 Undoped GaN layer 30 N-type GaN layer 40 N-type electron blocking layer 50 SiN layer 51 <![CDATA[Al a Si 1-a N layer]]> 52 superlattice layer 53 <![CDATA[Si doped with Al b Ga 1-b N layer]]> 531 <![CDATA[Non-Al-doped x In y Ga 1-x-y N layer]]> 532 Multiple quantum well layers 60 electron blocking layer 70 P-type GaN layer 80

[0025] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0026] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The drawings illustrate several embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0027] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] The present invention provides a high-efficiency light-emitting diode epitaxial wafer and a preparation method thereof, wherein an N-type electron blocking layer is inserted between the N-type GaN layer and the multi-quantum well layer, wherein the electron blocking layer comprises a SiN layer, an AlN layer and a SiN layer sequentially deposited on the N-type GaN layer. a Si 1-a N layer and super lattice layer, the super lattice layer includes Si doped Al deposited alternately in a preset period b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y N layer; through SiN layer and Al a Si 1-a The N layer blocks the dislocation from extending into the epitaxial layer, and the Si-doped Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y N layer, effectively reducing the non-radiative recombination of electrons in the N-type GaN layer through the multi-quantum well layer and the holes in the P-type GaN layer, thereby improving the radiative recombination efficiency of electrons and holes in the N-type GaN layer in the multi-quantum well layer.

[0030] For details, see Figure 1 The high-efficiency light-emitting diode epitaxial wafer provided by the embodiment of the present invention comprises: a substrate 10, and a buffer layer 20, a non-doped GaN layer 30, an N-type GaN layer 40, an N-type electron blocking layer 50, a multi-quantum well layer 60, an electron blocking layer 70 and a P-type GaN layer 80 sequentially deposited on the substrate 10; the N-type electron blocking layer 50 comprises a SiN layer 51, an AlN layer 52, and a P-type GaN layer 80 sequentially deposited on the N-type GaN layer 40. a Si 1-a The N layer 52 and the superlattice layer 53 are alternately deposited on the Al a Si 1-a Si doped with Al on the N layer 52 b Ga 1-b N layer 531 and non-Al doped x In y Ga 1-x-y N layer 532.

[0031] Specifically, substrate 10 can be selected from the group consisting of a sapphire substrate, a SiO2-sapphire composite substrate, a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, and a zinc oxide substrate. Sapphire substrates are currently one of the most commonly used substrates for light-emitting diodes. Sapphire substrates feature mature manufacturing processes, low prices, convenient substrate access, high cost-effectiveness, ease of cleaning and handling, and excellent stability at high temperatures. However, sapphire substrates have significant surface defects, and directly depositing an epitaxial layer on the substrate can easily cause mismatch and generate significant internal stress. Therefore, before depositing the epitaxial layer on the substrate, a buffer layer 20 needs to be deposited on substrate 10 to mitigate surface defects on the sapphire substrate to a certain extent. Specifically, buffer layer 20 can be an AlN buffer layer with a thickness of 10nm-15nm.

[0032] The undoped GaN layer 30 is deposited on the buffer layer 20. The thickness of the undoped GaN layer 30 is 1um-5um. The growth temperature of the undoped GaN layer 30 is high and the pressure is low. The quality of the prepared GaN crystal is better. At the same time, as the thickness of the GaN increases, the compressive stress is released through stacking faults, the line defects are reduced, the crystal quality is improved, and the reverse leakage is reduced. However, at the same time, the increase in the thickness of the GaN layer consumes a large amount of Ga source material, which greatly increases the epitaxial cost of the light-emitting diode (LED). Therefore, in order to balance the quality and production cost of the light-emitting diode, it is preferred that the undoped GaN layer 30 is 2um-3um. The main function of the N-type GaN layer 40 in the LED is to provide sufficient electrons for the LED to emit light. The electrons in the N-type GaN layer 40 undergo radiative recombination with the holes in the multi-quantum well layer 60 to emit light. The more electrons and holes are radiatively recombinated, the better the light-emitting effect of the LED. Specifically, the thickness of the N-type GaN layer 40 is 2um-3um. A sufficiently thick N-type GaN layer can effectively release the stress and improve the luminous efficiency of the light-emitting diode.

[0033] The N-type electron blocking layer 50 includes a SiN layer 51, an AlN layer 52, and a SiN layer 53 sequentially deposited on the N-type GaN layer 40. a Si 1-a N layer 52 and superlattice layer 53, specifically, the thickness of SiN layer 51 is 1nm-100nm, Al a Si 1-a The thickness of the N layer 52 is 1nm-100nm, and the Si is doped with Al b Ga 1-b The thickness of the N layer 531 is 1nm-50nm and is not doped with Al. x In y Ga 1-x-y The thickness of the N layer 532 is 1 nm to 10 nm. a Si 1-aIn the N layer, the Al content gradually increases along the growth direction of the epitaxial wafer, and the value of a is 0.01-1, that is, in the Al a Si 1-a The Al component content in the N layer is 0.01-1 and gradually increases along the growth direction of the epitaxial wafer.

[0034] Since the GaN-based material is epitaxially grown, although a buffer layer 20 is added to the surface of the substrate 10, the defects of the substrate 10 cannot be completely eliminated. Therefore, when the GaN-based material is epitaxially grown on the buffer layer, heterogeneous defects may be generated, resulting in lattice mismatch and thermal mismatch, and then dislocations are easily generated along the growth direction of the epitaxial layer. However, when Si is doped in the GaN-based material, Si will be accumulated along the dislocations, resulting in LED leakage. Therefore, the SiN layer 51 and AlN layer 52 are deposited on the N-type GaN layer 40. a Si 1-a The N layer 52 forms a dense film on the N-type GaN layer 40, effectively blocking dislocations from extending in the extension direction of the epitaxial layer, reducing heterogeneous defects, lowering the concentration of Si doping on dislocations, and preventing leakage.

[0035] Specifically, Al a Si 1-a In the N layer 52, the Al component gradually increases along the growth direction of the epitaxial wafer, so that Al a Si 1-a The potential barrier of the N layer 52 is relatively high, which can reduce the rate at which electrons in the N-type GaN layer 40 flow to the multi-quantum well layer 60. b Ga 1-b The value of b in the N layer 531 is 0-0.5, and the concentration of Si doping is 1*10 16 atoms / cm 3 -1*10 18 atoms / cm 3 . Non-doped Al x In y Ga 1-x-y The value of x in the N layer 532 is 0-0.1, and the value of y is 0-0.1. a Si 1-a Si doped with Al on the N layer 52 b Ga 1-b N layer 531 and non-Al doped x In y Ga 1-x-y The period of N layer 532 is 1-20. Alternating deposition of Si doped with Al b Ga 1-b N layer 531 and non-Al doped x In y Ga 1-x-yThe superlattice layer 53 formed by the N layer 532 constitutes an alternating barrier layer / potential well layer; the superlattice layer 53 forms a structure with high and low energy band variations, and the electrons in the N-type GaN layer 40 are in the Si-doped Al b Ga 1-b In the N layer 531, the electron flow rate is reduced due to its higher potential barrier; in the non-doped Al x In y Ga 1-x-y Since the In atomic radius in the N layer 532 is relatively large, it has a clay effect, which keeps some electrons in the potential well layer. By alternately depositing the barrier layer / potential well layer, the non-radiative recombination of electrons rushing into the multi-quantum well layer and the holes in the P-type GaN layer is effectively reduced, thereby improving the efficiency of electron recombination with holes in the multi-quantum well layer.

[0036] See also Figure 2 , is a method for preparing a high-efficiency light-emitting diode epitaxial wafer in an embodiment of the present invention. Specifically, for preparing the above-mentioned high-efficiency light-emitting diode epitaxial wafer, the method for preparing a high-efficiency light-emitting diode epitaxial wafer provided by the present invention includes steps S10-S90.

[0037] Step S10, providing a substrate;

[0038] Specifically, the substrate can be selected from the group consisting of a sapphire substrate, a SiO2-sapphire composite substrate, a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, and a zinc oxide substrate. Sapphire is currently the most commonly used substrate material for GaN-based LEDs. The greatest advantages of sapphire substrates are mature technology, good stability, and low production costs. Therefore, in this embodiment, sapphire is selected as the substrate.

[0039] Step S20, depositing a buffer layer on the substrate;

[0040] Specifically, the buffer layer can be deposited on the substrate by physical vapor deposition (PVD), and the thickness of the buffer layer is 15nm-20nm. In this embodiment, an AlN buffer layer is used to control substrate crystal defects, improve the quality of subsequent grown crystals, and alleviate the stress between the substrate and the epitaxial layer caused by lattice mismatch and thermal mismatch.

[0041] Step S30 , pre-treating the substrate on which the buffer layer has been deposited.

[0042] Specifically, the sapphire substrate on which the buffer layer has been deposited is transferred to the A7 Metal-organic Chemical Vapor Deposition (MOCVD) equipment of the China Microelectronics Corporation. In the MOCVD equipment, one of high-purity H2 (hydrogen), high-purity N2 (nitrogen), and a mixture of high-purity H2 and high-purity N2 can be used as a carrier gas, high-purity NH3 as an N source, trimethylgallium (TMGa) and triethylgallium (TEGa) as gallium sources, trimethylindium (TMIn) as an indium source, trimethylaluminum (TMAl) as an aluminum source, silane (SiH4) as an N-type dopant, and bis(cyclopentadienyl)magnesium (CP2Mg) as a P-type dopant can be used for epitaxial growth.

[0043] Specifically, the substrate on which the buffer layer has been deposited is treated in an H2 atmosphere for 1-10 minutes at a treatment temperature of 1000°C to 1200°C, and then nitrided to improve the crystal quality of the buffer layer and effectively improve the crystal quality of the subsequently deposited GaN epitaxial layer.

[0044] Step S40: depositing an undoped GaN layer on the buffer layer.

[0045] After the buffer layer is deposited on the substrate and nitrided, an undoped GaN layer is deposited in an MOCVD device, using high-purity NH3 as the N source, and trimethyl gallium (TMGa) and triethyl gallium (TEGa) as the gallium source; the growth temperature of the undoped GaN layer is 1050℃-1200℃, the pressure is 100torr-600torr, and the thickness is 1um-5um; optionally, the growth temperature of the undoped GaN layer is 1100℃, and the growth pressure is 150torr. The growth temperature of the undoped GaN layer is higher and the pressure is lower, and the prepared GaN crystal quality is better. In addition, as the GaN thickness increases, the compressive stress in the undoped GaN layer will be released through stacking faults, reducing line defects, improving crystal quality, and reducing reverse leakage. However, increasing the thickness of the GaN layer consumes more Ga source materials, which greatly increases the epitaxial cost of the LED. Optionally, the undoped GaN growth thickness is 2um-3um, which not only saves production costs, but also has higher crystal quality of the GaN material.

[0046] Step S50 , depositing an N-type GaN layer on the undoped GaN layer.

[0047] Specifically, after depositing the undoped GaN layer, the N-type GaN layer is deposited in the MOCVD device. The growth temperature of the N-type GaN layer is 1050℃-1200℃, the pressure is 100torr-600torr, the deposition thickness is 2um-3um, and Si is used for doping. The Si doping concentration is 1*10 19 atoms / cm 3 -5*1019 atoms / cm 3 Optionally, the N-type GaN layer growth temperature is 1120°C, the growth pressure is 100 torr, the growth thickness is 2um-3um, and the Si doping concentration is 2.5*10 19 atoms / cm 3 . Doping the GaN layer with impurity Si can provide sufficient electrons for the LED to emit light. The electrons in the N-type GaN layer 40 and the holes in the multi-quantum well layer 60 undergo radiation recombination to emit light. The more electrons and holes are radiated and recombinated, the better the light-emitting effect of the LED. In addition, the resistivity of the N-type GaN layer is higher than the resistivity of the transparent electrode on the P-type GaN layer. Therefore, sufficient Si doping can effectively increase the electrons in the N-type GaN layer, reduce the layer resistivity of the N-type GaN, and allow more electrons to enter the multi-quantum well layer for recombination. In addition, sufficient thickness of N-type GaN can effectively reduce line defects, release compressive stress, and improve the luminous efficiency of the light-emitting diode.

[0048] Step S60 , depositing an N-type electron blocking layer on the N-type GaN layer.

[0049] Specifically, SiN layer, Al a Si 1-a N layer and super lattice layer, wherein the super lattice layer comprises Si doped Al deposited alternately in a preset period b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y N layer. Specifically, the deposition thickness of the SiN layer is 1nm-100nm, and the Al a Si 1-a The deposition thickness of the N layer is 1nm-100nm, and the Si is doped with Al b Ga 1-b The deposition thickness of the N layer is 1nm-50nm, and it is not doped with Al. x In y Ga 1-x-y The deposition thickness of the N layer is 1nm-10nm. a Si 1-a In the N layer, the Al content gradually increases along the growth direction of the epitaxial wafer, and the value of a is 0.01-1. b Ga 1-b The value of b in the N layer is 0-0.5, and the concentration of doped Si is 1*10 16 atoms / cm 3 -1*10 18 atoms / cm 3 . Non-doped Al x Iny Ga 1-x-y In the N layer 532, the value of x is 0-0.1, and the value of y is 0-0.1; optionally, the deposition thickness of the SiN layer is 65nm, and the Al a Si 1-a The deposition thickness of the N layer is 50nm, and the Si is doped with Al b Ga 1-b The deposition thickness of the N layer is 25nm, and the non-doped Al x In y Ga 1-x-y The deposition thickness of the N layer is 2.5nm. a Si 1-a In the N layer, the Al content gradually increases to 0.6 along the growth direction of the epitaxial wafer. b Ga 1-b The value of b in the N layer is 0.3, and the concentration of Si doping is 5*10 17 atoms / cm 3 , non-Al-doped x In y Ga 1-x-y In the N layer 532, the value of x is 0.08 and the value of y is 0.05.

[0050] In addition, in the deposition growth of N-type electron blocking layer, SiN layer and Al a Si 1-a The deposition temperature of the N layer is 900℃-1100℃, and the Si-doped Al is deposited and grown. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The temperature of the N layer is 800℃-1000℃. The growth atmosphere during the deposition and growth of the N-type electron blocking layer is a mixture of N2 / NH3 with a ratio of 1:5-5:1, and the growth pressure during the growth process is 50torr-300torr. Alternately deposited Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The deposition cycle of the N layer is 1-20. Optionally, the SiN layer and the Al a Si 1-a The deposition temperature of the N layer is 1020℃, and the Si-doped Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The temperature of the N layer is 900℃, the SiN layer and the Al a Si1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The growth atmosphere during the N layer deposition growth process is a mixture of N2 / NH3 with a ratio of 1:3, and the growth pressure during the growth process is 150torr. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The deposition cycle of the N layer is 6.

[0051] By depositing SiN layer and Al on N-type GaN layer a Si 1-a N layer, so that it forms a dense film on the N-type GaN layer, which can effectively prevent the dislocations on the N-type GaN layer from extending to the epitaxial layer, reduce heterogeneous defects, and further reduce the Si doping accumulation on the dislocations to prevent leakage. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The superlattice structure formed by the N layer forms a barrier layer and a potential well layer, which makes the energy band of the superlattice layer vary. The electrons in the N-type GaN layer are doped with Al in Si. b Ga 1-b In the N layer, due to its higher potential barrier, the electron flow rate is reduced. x In y Ga 1-x-y Since the In atomic radius in the N layer is large, it has a clay effect, which keeps the electrons in the potential well layer. Therefore, through the periodic alternation of the barrier layer / potential well layer, the electrons in the N-type GaN layer are effectively reduced from rushing through the multi-quantum well layer to reach the P-type GaN layer to undergo non-radiative recombination with holes, thereby improving the radiative recombination efficiency of electrons and holes in the quantum well layer.

[0052] Step S70 , depositing a multi-quantum well layer on the N-type electron blocking layer.

[0053] Specifically, the multi-quantum well layer is an alternately deposited InGaN quantum well layer and an AlGaN quantum barrier layer, with a deposition cycle number of 6-12, wherein the InGaN quantum well layer is deposited and grown at a temperature of 790°C-810°C, a thickness of 2nm-5nm, a growth pressure of 50torr-300torr, and an In component of 0.01-0.3. The AlGaN quantum barrier layer is deposited and grown at a temperature of 800°C-900°C, a thickness of 5nm-15nm, a growth pressure of 50torr-300torr, and an Al component of 0.01-0.1. Optionally, the multi-quantum well layer is an alternately deposited InGaN quantum well layer and an AlGaN quantum barrier layer, with a deposition cycle number of 10, wherein the InGaN quantum well layer is deposited and grown at a temperature of 795°C, a thickness of 3.5nm, a growth pressure of 200torr, and an In component of 0.15. The AlGaN quantum barrier layer was deposited at a temperature of 855°C, with a thickness of 9.8nm, a growth pressure of 200 Torr, and an Al composition of 0.05. The multi-quantum well layer is where electrons and holes radiate and recombine. A reasonable structural design can significantly increase the overlap of electron and hole wave functions, thereby improving the luminous efficiency of LED devices.

[0054] Step S80: depositing an electron blocking layer on the multi-quantum well layer.

[0055] Specifically, the electron blocking layer is Al n In m GaN layer, thickness is 10nm-40nm, growth temperature is 900℃-1000℃, growth pressure is 100torr-300torr, among which Al n In m The value of n in the GaN layer is 0.005-0.1, and the value of m is 0.01-0.2. Optionally, the thickness of the electron blocking layer is 15nm, the growth temperature is 965℃, and the growth pressure is 200torr. n In m The Al content in the GaN layer gradually increases from 0.01 to 0.05 along the epitaxial growth direction, with m being 0.01. The electron blocking layer effectively limits electron overflow from the multi-quantum well layer while also reducing the barrier to holes in the P-type GaN layer, thereby increasing the efficiency of hole injection into the multi-quantum wells, reducing carrier Auger recombination, and improving the luminous efficiency of the light-emitting diode.

[0056] Step S90 , depositing a P-type GaN layer on the electron blocking layer.

[0057] Specifically, the growth temperature of the P-type GaN layer is 900-1050°C, the thickness is 10nm-50nm, the growth pressure is 100torr-600torr, and the Mg doping concentration is 1*10 19 atoms / cm 3~1*10 21 atoms / cm 3 Optional, P-type GaN layer growth temperature 985 ℃, thickness 15nm, growth pressure 200torr, Mg doping concentration 2*10 20 atoms / cm 3 Excessively high Mg doping concentrations can damage crystal quality, while low doping concentrations can affect hole concentration. Furthermore, for LED structures containing V-pits, a higher growth temperature for the P-type GaN layer also facilitates merging the V-pits, resulting in smooth-surfaced LED epitaxial wafers.

[0058] Example 1

[0059] A high-efficiency light-emitting diode epitaxial wafer, in this embodiment, uses a sapphire substrate, which has the advantages of good thermal and chemical stability, high mechanical strength, mature technology, and relatively low price. a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The thickness of the N layer is 1nm / 85nm / 50nm / 5nm, and the Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The Al composition in the N layer is 0.01 / 0.5 / 0.05, and Si doped with Al b Ga 1-b The concentration of Si doping in the N layer is 1*10 16 atoms / cm 3 , non-Al-doped x In y Ga 1-x-y The In component in the N layer is 0. The growth atmosphere during the deposition and growth of the N-type electron blocking layer is a mixture of N2 / NH3 with a ratio of 1:5. The Si doped with Al is deposited alternately. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The deposition cycle of the N layer is 1.

[0060] Example 2

[0061] The difference between the light emitting diode epitaxial wafer in this embodiment and the light emitting diode epitaxial wafer in embodiment 1 is that the SiN layer, Ala Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The thickness of the N layer is 10nm / 50nm / 45nm / 3nm, and the Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The Al composition in the N layer is 0.1 / 0.01 / 0, and Si doped with Al b Ga 1-b The concentration of Si doping in the N layer is 1*10 17 atoms / cm 3 , non-Al-doped x In y Ga 1-x-y The In content in the N layer is 0.05. The growth atmosphere during the deposition and growth of the N-type electron blocking layer is a mixture of N2 / NH3 with a ratio of 1:3. The Si doped with Al is deposited alternately. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The deposition cycle of the N layer is 12.

[0062] Example 3

[0063] The difference between the light emitting diode epitaxial wafer in this embodiment and the light emitting diode epitaxial wafer in embodiment 1 is that the SiN layer, Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The thickness of the N layer is 30nm / 55nm / 30nm / 2.5nm, and the Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The Al composition in the N layer is 0.6 / 0 / 0.1, and Si doped with Al b Ga 1-b The concentration of Si doping in the N layer is 2*10 16atoms / cm 3 , non-Al-doped x In y Ga 1-x-y The composition of In in the N layer is 0.1. The growth atmosphere during the deposition and growth of the N-type electron blocking layer is a mixture of N2 / NH3 with a ratio of 1:4. The Si doped with Al is deposited alternately. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The deposition cycle of the N layer is 5.

[0064] Example 4

[0065] The difference between the light emitting diode epitaxial wafer in this embodiment and the light emitting diode epitaxial wafer in embodiment 1 is that the SiN layer, Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The thickness of the N layer is 55nm / 100nm / 25nm / 1nm, and the Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The Al composition in the N layer is 0.4 / 0.2 / 0.06, and Si doped with Al b Ga 1-b The concentration of Si doping in the N layer is 5*10 17 atoms / cm 3 , non-Al-doped x In y Ga 1-x-y The In component of the N layer is 0.08. The growth atmosphere during the deposition and growth of the N-type electron blocking layer is a mixture of N2 / NH3 with a ratio of 2:1. The Si doped with Al is deposited alternately. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The deposition cycle of the N layer is 4.

[0066] Example 5

[0067] The difference between the light emitting diode epitaxial wafer in this embodiment and the light emitting diode epitaxial wafer in embodiment 1 is that the SiN layer, Al a Si1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The thickness of the N layer is 65nm / 50nm / 40nm / 6nm, and the Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The Al composition in the N layer is 0.8 / 0.01 / 0.04, and Si doped with Al b Ga 1-b The concentration of Si doping in the N layer is 2*10 17 atoms / cm 3 , non-Al-doped x In y Ga 1-x-y The In content in the N layer is 0.05. The growth atmosphere during the deposition and growth of the N-type electron blocking layer is a mixture of N2 / NH3 with a ratio of 1:3. The Si doped with Al is deposited alternately. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The deposition cycle of the N layer is 6.

[0068] Example 6

[0069] The difference between the light emitting diode epitaxial wafer in this embodiment and the light emitting diode epitaxial wafer in embodiment 1 is that the SiN layer, Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The thickness of the N layer is 75nm / 10nm / 1nm / 10nm, and the Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The Al composition in the N layer is 0.7 / 0.4 / 0.08, and Si doped with Al b Ga 1-b The concentration of Si doping in the N layer is 8*10 16 atoms / cm3 , non-Al-doped x In y Ga 1-x-y The In content in the N layer is 0.02. The growth atmosphere during the deposition and growth of the N-type electron blocking layer is a mixture of N2 / NH3 with a ratio of 1:1. The Si doped with Al is deposited alternately. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The deposition cycle of the N layer is 1.

[0070] Example 7

[0071] The difference between the light emitting diode epitaxial wafer in this embodiment and the light emitting diode epitaxial wafer in embodiment 1 is that the SiN layer, Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The thickness of the N layer is 80nm / 50nm / 35nm / 6nm, and the Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The Al composition in the N layer is 1 / 0.3 / 0.06, and Si doped with Al b Ga 1-b The concentration of Si doping in the N layer is 1*10 18 atoms / cm 3 , non-Al-doped x In y Ga 1-x-y The composition of In in the N layer is 0.04. The growth atmosphere during the deposition and growth of the N-type electron blocking layer is a mixture of N2 / NH3 with a ratio of 5:1. The Si doped with Al is deposited alternately. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The deposition cycle of the N layer is 20.

[0072] Example 8

[0073] The difference between the light emitting diode epitaxial wafer in this embodiment and the light emitting diode epitaxial wafer in embodiment 1 is that the SiN layer, Al a Si 1-aN layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The thickness of the N layer is 100nm / 80nm / 35nm / 5nm respectively, and the Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The Al composition in the N layer is 0.95 / 0.5 / 0.03, and Si doped with Al b Ga 1-b The concentration of Si doping in the N layer is 5*10 17 atoms / cm 3 , non-Al-doped x In y Ga 1-x-y The In content in the N layer is 0.05. The growth atmosphere during the deposition and growth of the N-type electron blocking layer is a mixture of N2 / NH3 with a ratio of 1:2. The Si doped with Al is deposited alternately. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The deposition cycle of the N layer is 7.

[0074] Example 9

[0075] The difference between the light emitting diode epitaxial wafer in this embodiment and the light emitting diode epitaxial wafer in embodiment 1 is that the SiN layer, Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The thickness of the N layer is 20nm / 1nm / 25nm / 1nm, and the Al a Si 1-a N layer, Si doped with Al b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The Al composition in the N layer is 0.85 / 0.3 / 0.1, and Si doped with Al b Ga 1-b The concentration of Si doping in the N layer is 8*10 17 atoms / cm 3, non-Al-doped x In y Ga 1-x-y The composition of In in the N layer is 0.1, and the growth atmosphere during the deposition and growth of the N-type electron blocking layer is a mixture of N2 / NH3 with a ratio of 1:3. The Si doped with Al is deposited alternately. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y The deposition cycle of the N layer is 15.

[0076] Control Example

[0077] The light emitting diode epitaxial wafer in this embodiment is different from the light emitting diode epitaxial wafer in embodiment 1 in that no N-type electron blocking layer is inserted between the N-type GaN layer and the multi-quantum well layer.

[0078] Please refer to Table 1, which shows the comparison of some parameters of the above embodiments and comparative examples and the corresponding light transmittance comparison results.

[0079] Table 1

[0080]

[0081] As can be seen from Table 1, the photoelectric efficiency of the high-efficiency light-emitting diode epitaxial wafer provided by the present invention is improved by 1%-5% compared with the light-emitting diode epitaxial wafer currently prepared in mass production.

[0082] It should be noted that the above implementation process is only intended to illustrate the feasibility of this application. This does not mean that the high-efficiency light-emitting diode epitaxial wafer of this application is limited to the above-mentioned implementation process. On the contrary, as long as the high-efficiency light-emitting diode epitaxial wafer of this application can be implemented, it can be included in the feasible implementation scheme of this application. In addition, the structure of the light-emitting diode epitaxial wafer in the embodiment of the present invention corresponds to the method for preparing the light-emitting diode epitaxial wafer of the present invention, and the specific implementation details are also the same, which will not be repeated here.

[0083] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0084] The above embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A high-efficiency light-emitting diode epitaxial wafer, characterized in that: The method comprises a substrate, and a buffer layer, an undoped GaN layer, an N-type GaN layer, an N-type electron blocking layer, a multi-quantum well layer, an electron blocking layer and a P-type GaN layer sequentially deposited on the substrate; The N-type electron blocking layer includes a SiN layer, an AlN layer, and a SiN layer sequentially deposited on the N-type GaN layer. a Si 1-a N layer and super lattice layer, wherein the super lattice layer comprises Si doped Al deposited alternately in a preset period. b Ga 1-b N layer and non-doped Al x In y Ga 1-x-y N-layer; In the Al a Si 1-a The Al content in the N layer gradually increases along the growth direction of the epitaxial wafer, and the value of a is 0.01-1; The Si doped Al b Ga 1-b The value of b in the N layer is 0-0.5; The non-doped Al x In y Ga 1-x-y In the N layer, the value of x is 0-0.1, and the value of y is 0-0.

1.

2. The epitaxial wafer according to claim 1, characterized in that The Si doped Al b Ga 1-b The concentration of Si doping in the N layer is 1*10 16 atoms / cm 3 -1*10 18 atoms / cm 3 .

3. The epitaxial wafer according to claim 1, characterized in that The thickness of the SiN layer is 1nm-100nm, and the Al a Si 1-a The thickness of the N layer is 1nm-100nm, and the Si doped with Al b Ga 1-b The thickness of the N layer is 1nm-50nm, and the non-doped Al x In y Ga 1-x-y The thickness of the N layer is 1nm-10nm.

4. The epitaxial wafer according to claim 1, characterized in that The preset period is 1-20.

5. A method for preparing the epitaxial wafer according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: providing a substrate; Depositing a buffer layer, an undoped GaN layer, an N-type GaN layer, an N-type electron blocking layer, a multi-quantum well layer, an electron blocking layer and a P-type GaN layer in sequence on the substrate; Wherein, the N-type electron blocking layer comprises a SiN layer, an Al a Si 1-a N layer and super lattice layer, wherein the super lattice layer comprises Si doped Al deposited alternately in a preset period. b Ga 1-b N layer and non-doped Al x In y Ga 1-x- y N-layer; In the Al a Si 1-a The Al content in the N layer gradually increases along the growth direction of the epitaxial wafer, and the value of a is 0.01-1; The Si doped Al b Ga 1-b The value of b in the N layer is 0-0.5; The non-doped Al x In y Ga 1-x-y In the N layer, the value of x is 0-0.1, and the value of y is 0-0.

1.

6. The preparation method according to claim 5, characterized in that: The growth atmosphere during the growth of the N-type electron blocking layer is a mixed gas with an N2 / NH3 composition ratio of 1:5-5:

1.

7. The preparation method according to claim 5, characterized in that: The growth pressure during the growth of the N-type electron blocking layer is 50 torr-300 torr; The SiN layer and the Al a Si 1-a The deposition growth temperature of the N layer is 900° C.-1100° C., and the deposition growth temperature of the superlattice layer is 800° C.-1000° C.

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