CN116682897A - Light-emitting diode epitaxial wafer, preparation method thereof and light-emitting diode - Google Patents
Light-emitting diode epitaxial wafer, preparation method thereof and light-emitting diode Download PDFInfo
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- 238000002360 preparation method Methods 0.000 title claims abstract description 32
- 239000000758 substrate Substances 0.000 claims abstract description 59
- 229910052594 sapphire Inorganic materials 0.000 claims abstract description 54
- 239000010980 sapphire Substances 0.000 claims abstract description 54
- 239000002131 composite material Substances 0.000 claims abstract description 47
- 229910002704 AlGaN Inorganic materials 0.000 claims abstract description 29
- 238000000034 method Methods 0.000 claims description 41
- 238000004519 manufacturing process Methods 0.000 claims description 19
- 230000000903 blocking effect Effects 0.000 claims description 15
- 238000000059 patterning Methods 0.000 claims description 4
- 238000007781 pre-processing Methods 0.000 claims description 4
- 230000004888 barrier function Effects 0.000 abstract description 7
- 239000004065 semiconductor Substances 0.000 abstract description 4
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 60
- 229910002601 GaN Inorganic materials 0.000 description 59
- 239000013078 crystal Substances 0.000 description 41
- 230000001105 regulatory effect Effects 0.000 description 20
- 230000000694 effects Effects 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 9
- 238000005336 cracking Methods 0.000 description 9
- 239000000463 material Substances 0.000 description 9
- 239000002019 doping agent Substances 0.000 description 6
- 229910017083 AlN Inorganic materials 0.000 description 5
- 238000000137 annealing Methods 0.000 description 5
- 230000002349 favourable effect Effects 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- 239000011777 magnesium Substances 0.000 description 4
- 229910052749 magnesium Inorganic materials 0.000 description 4
- 239000002243 precursor Substances 0.000 description 4
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical group [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 229910000077 silane Inorganic materials 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- ZSWFCLXCOIISFI-UHFFFAOYSA-N endo-cyclopentadiene Natural products C1C=CC=C1 ZSWFCLXCOIISFI-UHFFFAOYSA-N 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- 238000010899 nucleation Methods 0.000 description 2
- 230000006911 nucleation Effects 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- JLTRXTDYQLMHGR-UHFFFAOYSA-N trimethylaluminium Chemical compound C[Al](C)C JLTRXTDYQLMHGR-UHFFFAOYSA-N 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- UOSXPFXWANTMIZ-UHFFFAOYSA-N cyclopenta-1,3-diene;magnesium Chemical compound [Mg].C1C=CC=C1.C1C=CC=C1 UOSXPFXWANTMIZ-UHFFFAOYSA-N 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000003631 expected effect Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- RGGPNXQUMRMPRA-UHFFFAOYSA-N triethylgallium Chemical compound CC[Ga](CC)CC RGGPNXQUMRMPRA-UHFFFAOYSA-N 0.000 description 1
- XCZXGTMEAKBVPV-UHFFFAOYSA-N trimethylgallium Chemical compound C[Ga](C)C XCZXGTMEAKBVPV-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/005—Processes
- H01L33/0062—Processes for devices with an active region comprising only III-V compounds
- H01L33/0066—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound
- H01L33/007—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound comprising nitride compounds
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/12—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a stress relaxation structure, e.g. buffer layer
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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- Microelectronics & Electronic Packaging (AREA)
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Abstract
The invention discloses a light-emitting diode epitaxial wafer and a preparation method thereof, and a light-emitting diode, and relates to the technical field of semiconductors, wherein the preparation method comprises the following steps: providing a patterned sapphire substrate; introducing NH with a first preset flow rate at a first preset temperature and a first preset pressure 3 Pretreating the surface of the patterned sapphire substrate for a first preset time to form a composite layer; introducing TMGa with a second preset flow rate at a second preset temperature and a second preset pressure, and growing a second preset time on the composite layer to form a Ga layer, wherein the first preset temperature is higher than the second preset temperature; alGaN buffer layer, undoped GaN layer, N-type doped GaN layer, multiple quantum well layer, electron barrier layer, P-type doped GaN layer and P-type contact layer are sequentially grown on Ga layer, and the invention can solve the problem that dislocation density is increased or warping is serious caused by growing GaN or AlGaN or AlN buffer layer on patterned sapphire (PSS) substrate in the prior artTechnical problems of (2).
Description
Technical Field
The invention relates to the technical field of semiconductors, in particular to a light-emitting diode epitaxial wafer, a preparation method thereof and a light-emitting diode.
Background
With the development of semiconductor technology, group III nitride semiconductors typified by gallium nitride (GaN) have received attention as ideal materials for electronic and optoelectronic devices such as Light Emitting Diodes (LEDs), lasers (LDs), and High Electron Mobility Transistors (HEMTs). In the epitaxial growth process of the LED, due to the lack of substrate materials matched with GaN, larger lattice mismatch and thermal mismatch exist between a heterogeneous substrate and a GaN film, so that the crystal quality of the GaN film is reduced, and the dislocation density of the GaN film is as high as 10 8 -10 10 cm -2 The high density of dislocations may form leakage paths in the GaN-based devices, degrading device performance and lifetime.
At present, a common light-emitting diode epitaxial wafer generally adopts a patterned sapphire (PSS) substrate to replace a flat substrate so as to reduce the dislocation density of a GaN film and improve the crystal, and then low-temperature GaN or AlGaN is grown on the patterned sapphire (PSS) substrate as a buffer layer, so that the growth method is favorable for the adjustment of warping, the crystal quality of the GaN epitaxial layer can be improved to a certain extent, but the dislocation density is still higher overall; or sputtering an AlN film on a patterned sapphire (PSS) substrate as a buffer layer, wherein the defect density of the AlN buffer layer is reduced, the crystal quality of the GaN epitaxial layer can be improved, and the product performance is improved, but the sputtered AlN film as the buffer layer has great influence on the warping in the epitaxial growth, and impurity pollution exists in the process of turning the sputtering growth into the epitaxial growth.
Therefore, the existing preparation method of the light-emitting diode epitaxial wafer generally has the technical problems that the dislocation density is increased or the warping is serious due to the growth of the GaN or AlGaN or AlN buffer layer on the patterned sapphire (PSS) substrate.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a light-emitting diode epitaxial wafer, a preparation method thereof and a light-emitting diode, and aims to solve the technical problems that the dislocation density is increased or the warping is serious due to the growth of a GaN or AlGaN or AlN buffer layer on a patterned sapphire (PSS) substrate in the prior art.
The first aspect of the present invention provides a method for preparing a light emitting diode epitaxial wafer, which comprises:
providing a patterned sapphire substrate;
introducing NH with a first preset flow rate at a first preset temperature and a first preset pressure 3 Preprocessing the surface of the patterned sapphire substrate for a first preset time to form a composite layer;
introducing TMGa with a second preset flow rate at a second preset temperature and a second preset pressure, and growing a second preset time on the composite layer to form a Ga layer, wherein the first preset temperature is higher than the second preset temperature;
and an AlGaN buffer layer, an undoped GaN layer, an N-type doped GaN layer, a multiple quantum well layer, an electron blocking layer, a P-type doped GaN layer and a P-type contact layer are sequentially grown on the Ga layer.
Compared with the prior art, the invention has the beneficial effects that: the preparation method of the light-emitting diode epitaxial wafer can effectively reduce dislocation and warping, improve the crystal quality of the epitaxial layer grown subsequently, and specifically, introduce NH with a first preset flow rate at a first preset temperature and a first preset pressure 3 Pretreating the surface of the patterned sapphire substrate for a first preset time to form a composite layer, wherein the first preset temperature is higher than the second preset temperature, and NH can be formed by high-temperature growth 3 Is fully cracked to form N 3- And sufficiently diffuse into the patterned sapphire substrate such that a small amount of N 3- Blend in Al 3+ The lattice is used for forming an AlNO composite layer, the lattice constant of the AlNO composite layer is between the patterned sapphire substrate and the N-type doped GaN layer, dislocation density generated by lattice mismatch of the epitaxial layer which is grown subsequently is reduced, and the epitaxial layer with high crystal quality is grown; introducing TMGa with a second preset flow rate at a second preset temperature and a second preset pressure, growing for a second preset time on the composite layer to form a Ga layer, and slowing at a low temperatureThe slow growth is favorable for growing a micro-nano Ga crystal grain layer on the composite layer, and the growth of the Ga crystal grain layer is favorable for the rapid crystallization nucleation of a subsequent epitaxial layer GaN material, so that the crystal quality of the epitaxial layer is improved, and the warping problem is improved; thus, the technical problems that the dislocation density is increased or the warping is serious caused by the ubiquitous growth of the GaN or AlGaN or AlN buffer layer on the patterned sapphire (PSS) substrate are solved.
According to an aspect of the above technical solution, the first preset temperature is 1000 ℃ to 1200 ℃, and the second preset temperature is 650 ℃ to 750 ℃.
According to an aspect of the above technical solution, the first preset flow is 30L/min-50L/min, and the second preset flow is 50sccm-100sccm.
According to an aspect of the above technical solution, the first preset pressure is 100Torr-200Torr, and the second preset pressure is 100Torr-200Torr.
According to an aspect of the above technical solution, the first preset time is 1min-5min, and the second preset time is 30s-60s.
According to an aspect of the above technical solution, the composite layer is an AlNO composite layer, and the Ga layer is a Ga grain layer.
According to one aspect of the above technical scheme, the growth temperature of the AlGaN buffer layer is 800-900 ℃, and the growth pressure is 50Torr-100Torr.
The second aspect of the present invention provides a light emitting diode epitaxial wafer, which is prepared by the above preparation method, and the light emitting diode epitaxial wafer includes:
patterning the sapphire substrate;
the composite layer, the Ga layer, the AlGaN buffer layer, the undoped GaN layer, the N-type doped GaN layer, the multiple quantum well layer, the electron blocking layer, the P-type doped GaN layer and the P-type contact layer are sequentially laminated on the patterned sapphire substrate.
The third aspect of the present invention provides a light emitting diode, where the light emitting diode includes the light emitting diode epitaxial wafer described above.
Drawings
The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:
fig. 1 is a flowchart of a method for manufacturing a light emitting diode epitaxial wafer according to the present invention;
fig. 2 is a schematic structural diagram of an led epitaxial wafer according to the present invention;
description of the drawings element symbols:
the structure comprises a patterned sapphire substrate 100, a composite layer 101, a Ga layer 200, an AlGaN buffer layer 300, an undoped GaN layer 400, an N-type doped GaN layer 500, a multiple quantum well layer 600, an electron blocking layer 700, a P-type doped GaN layer 800 and a P-type contact layer 900.
Detailed Description
In order to make the objects, features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below. Several embodiments of the invention are presented in the figures. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "mounted" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," "upper," "lower," and the like are used herein for descriptive purposes only and not to indicate or imply that the apparatus or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the invention.
In the present invention, unless explicitly stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
Referring to fig. 1, a method for preparing a light emitting diode epitaxial wafer according to the present invention is shown, and the method comprises steps S10-S13:
step S10, providing a patterned sapphire substrate;
compared with a flat substrate, the patterned sapphire substrate can effectively reduce dislocation density of an epitaxial layer which is grown subsequently and improve crystal quality of the epitaxial layer which is grown subsequently.
Preferably, the (001) crystal orientation is adopted to pattern the sapphire Al 2 O 3 Is a substrate.
In addition, the patterned sapphire substrate needs to be pretreated to remove impurities and moisture from the surface of the patterned sapphire substrate.
Specifically, the patterned sapphire substrate is subjected to in-situ annealing treatment in a hydrogen atmosphere, wherein the annealing treatment temperature is 1100-1200 ℃, the pressure is 150Torr-500Torr, and the annealing treatment time is 5-10 min.
Step S11, introducing NH with a first preset flow rate at a first preset temperature and a first preset pressure 3 Preprocessing the surface of the patterned sapphire substrate for a first preset time to form a composite layer;
wherein the composite layer is an AlNO composite layer with the thickness of 1nm-10nm, and NH with a first preset flow is introduced at a first preset temperature and a first preset pressure 3 Can make part of NH 3 Adhering to the substrate surface, N in NH3 3- And patterning O in a sapphire substrate 2- Interdiffusion to make a small amount of N 3- Blend in Al 3+ And (3) a lattice, and forming an AlNO compound layer. Wherein the lattice constant of the AlNO material is between that of the patterned sapphire substrateAl 2 O 3 And dislocation density generated by lattice mismatch of the epitaxial layer which is grown subsequently is reduced between the material and the GaN material, and the epitaxial layer with high crystal quality is grown. The problems of dislocation density improvement or serious warping and the like caused by directly growing a GaN or AlGaN or AlN buffer layer on a patterned sapphire (PSS) substrate are avoided.
Specifically, the first preset temperature is 1000-1200 ℃, the first preset temperature is higher than the second preset temperature, and the high-temperature growth can enable NH 3 Is fully cracked to form N 3- And sufficiently diffuse into the patterned sapphire substrate such that a small amount of N 3- Blend in Al 3+ And (3) a lattice, and forming an AlNO compound layer.
When the first preset temperature is too high, the structure of the patterned sapphire substrate is damaged, so that cracks exist on the surface of the patterned sapphire substrate, and the quality of the epitaxial layer crystal grown later is reduced; when the first preset temperature is too low, NH 3 Low cracking rate, N 3+ Insufficient, alNO complex layer cannot be formed.
Similarly, when the first preset pressure is 100Torr-200Torr, the structure of the patterned sapphire substrate is damaged when the first preset pressure is too high, so that cracks exist on the surface of the patterned sapphire substrate, and the quality of the epitaxial layer crystal grown subsequently is reduced; when the first preset pressure is too low, NH 3 Low cracking rate, N 3+ Insufficient, the AlNO composite layer formed is too thin to achieve the desired effect.
The first preset time is 1-5 min, and when the first preset time is too long, the patterned sapphire substrate is corroded, so that the quality of the epitaxial layer crystal grown later is reduced; when the first preset time is too short, NH 3 Short cracking time, N 3+ Insufficient, the AlNO composite layer formed is too thin to achieve the desired effect.
Similarly, when the first preset flow is 30L/min-50L/min, the patterned sapphire substrate is corroded when the first preset flow is too large, so that the quality of the epitaxial layer crystal grown later is reduced; when the first preset flow is too small, cracking N 3+ Insufficient, the AlNO complex layer formed is too thin to be achievedExpected effect.
Step S12, introducing TMGa with a second preset flow rate at a second preset temperature and a second preset pressure, and growing a Ga layer on the composite layer for a second preset time to form a Ga layer, wherein the first preset temperature is higher than the second preset temperature;
wherein the Ga layer is a Ga crystal grain layer with the thickness of 0.5-5 nm. The first preset temperature is higher than the second preset temperature, the low-temperature slow growth is favorable for growing a micro-nano Ga crystal grain layer on the composite layer, the growth of the Ga crystal grain layer is favorable for the rapid crystallization nucleation of a subsequent epitaxial layer GaN material, and the crystal quality of the epitaxial layer is improved. The problems of dislocation density improvement or serious warping and the like caused by directly growing a GaN or AlGaN or AlN buffer layer on a patterned sapphire (PSS) substrate are avoided.
Specifically, the second preset temperature is 650-750 ℃, the second preset pressure is 100Torr-200Torr, and when the second preset temperature is too low, the Ga crystal grains have slow diffusion rate on the surface of the composite layer, so that the Ga crystal grains in the Ga crystal grain layer are unevenly distributed; when the second preset temperature is too high, the Ga grains grow too fast, resulting in Ga grain clusters.
Specifically, when the second preset flow is 50sccm-100sccm, the Ga grains in the Ga layer grow better, but the warpage is larger, so that cracks are generated on the surface of the epitaxial layer which grows later; when the second preset flow is too small, the Ga grains in the Ga layer grow unevenly, and the quality of the subsequently grown epitaxial layer is not obviously improved.
Specifically, the second preset time is 30s-60s, when the second preset time is too long, the middle Ga crystal grain of the Ga layer grows better, but the larger the warpage is, the more convex the warpage is, so that cracks are generated on the surface of the epitaxial layer which grows later; when the second preset time is too short, ga grains in the Ga layer grow unevenly and warp is concave, so that cracks are generated on the surface of the epitaxial layer which grows later.
Therefore, the warping degree of the Ga layer can be adjusted by controlling the second preset flow and the second preset time, so that the crystal quality of the epitaxial layer which is grown subsequently is improved, and the dislocation generation is reduced.
And S13, sequentially growing an AlGaN buffer layer, an undoped GaN layer, an N-type doped GaN layer, a multiple quantum well layer, an electron blocking layer, a P-type doped GaN layer and a P-type contact layer on the Ga layer.
Specifically, the temperature is regulated to 800-900 ℃, the pressure is regulated to 50Torr-100Torr, and an AlGaN buffer layer with the thickness of 30-200 nm is grown on the Ga layer, wherein the Al component of the AlGaN buffer layer is 0-1. The AlGaN buffer layer is used for releasing lattice mismatch and thermal mismatch between the patterned sapphire substrate and the N-type doped GaN layer.
The temperature is adjusted to 1000 ℃ to 1100 ℃, the pressure is adjusted to 100Torr to 500Torr, and an undoped GaN layer with the thickness of 1 μm to 3 μm is grown on the AlGaN buffer layer. The undoped GaN layer is crystallized and polymerized on the AlGaN buffer layer to form a continuous and flat substrate layer, so that the crystal growth of the N-type doped GaN layer is facilitated.
The temperature is regulated to 1000 ℃ to 1200 ℃, the pressure is regulated to 100Torr to 300Torr, an N-type doped GaN layer with the thickness of 1 mu m to 3 mu m is grown on the undoped GaN layer, wherein the doping agent of the N-type doped GaN layer is silane, and the doping concentration of silicon is 10 19 cm -3 -10 20 cm -3 . The N-type doped GaN layer is used for providing electrons for the multi-quantum well layer so that the electrons and the holes are radiated and compounded in the multi-quantum well layer to achieve the luminous effect of the LED epitaxial wafer.
Growing a multi-quantum well layer on the N-type doped GaN layer, wherein the multi-quantum well layer comprises a plurality of quantum well layers and quantum barrier layers which are stacked periodically, the quantum well layer is an InGaN layer, the In component is 0.1-0.5, the thickness of the quantum well layer is 1-4 nm, the growth temperature is 750-850 ℃, and the growth pressure is 50Torr-100Torr; the quantum barrier layer is a GaN layer, the thickness of the quantum barrier layer is 8nm-20nm, the growth temperature is 850-950 ℃, and the growth pressure is 50Torr-100Torr.
And (3) regulating the temperature to 950-1050 ℃, regulating the pressure to 50-100Torr, and growing an electron blocking layer with the thickness of 50-100 nm on the multi-quantum well layer, wherein the electron blocking layer is an AlGaN layer, and the Al component is 0.1-0.5. The electron blocking layer is used for limiting electron overflow.
Regulating the temperature to 900-1050 ℃ and regulating the pressureGrowing a P-type doped GaN layer with the thickness of 30nm-200nm on the electron blocking layer from 100Torr to 600Torr, wherein the doping agent of the P-type doped GaN layer is magnesium cyclopentadienyl, and the doping concentration of magnesium is 10 19 cm -3 -10 20 cm -3 . The P-type doped GaN layer provides holes for the multi-quantum well layer, so that electrons and holes are combined in the multi-quantum well layer in a radiation manner, and the light-emitting effect of the light-emitting diode epitaxial wafer is achieved.
And (3) regulating the temperature to 1000-1100 ℃, regulating the pressure to 50-100Torr, and growing a P-type contact layer with the thickness of 10-50 nm on the P-type doped GaN layer, wherein the P-type contact layer is an AlGaN layer, and the Al component is 0-0.3. The P-type contact layer is used for being jointed with the electrode to form ohmic contact, so that voltage is effectively reduced, and brightness is effectively improved.
And after the epitaxial structure is grown, the temperature of the reaction cavity is reduced, and annealing treatment is performed in a nitrogen atmosphere at 650-850 ℃ for 5-15 min.
Trimethylaluminum (TMAl), trimethylgallium, or triethylgallium (TMGa or TEGa) as a precursor of the group iii source, ammonia as a precursor of the group v source, silane as a precursor of the N-type dopant, and magnesium dicyclopentadiene as a precursor of the P-type dopant, nitrogen and hydrogen as carrier gases.
In addition, referring to fig. 2, a light emitting diode epitaxial wafer provided by the present invention is shown, where the light emitting diode epitaxial wafer includes:
patterning the sapphire substrate 100; the composite layer 101, the Ga layer 200, the AlGaN buffer layer 300, the undoped GaN layer 400, the N-type doped GaN layer 500, the multiple quantum well layer 600, the electron blocking layer 700, the P-type doped GaN layer 800 and the P-type contact layer 900 which are sequentially laminated on the patterned sapphire substrate 100;
wherein, the composite layer 101 is an AlNO composite layer with a thickness of 1nm-10nm, when the thickness of the composite layer 101 is too thick, the structure of the patterned sapphire substrate 100 will be damaged, the effect of the patterned sapphire substrate 101 is weakened, and when the thickness of the composite layer 101 is too thin, the formed AlNO composite layer is too thin to achieve the expected effect.
The Ga layer 200 is a Ga crystal grain layer, the grain diameter is 0.5nm-5nm, when the grain diameter of the Ga layer 200 is overlarge, the surface of the Ga layer 200 is unevenly distributed, the warping degree is higher, and cracks are generated on the surface of an epitaxial layer which grows subsequently; when the grain size of the Ga layer 200 is too small, dislocations or voids exist between Ga grains, which will increase dislocations of the epitaxial layer to be grown later, resulting in degradation of crystal quality.
In addition, the invention also provides a light-emitting diode, which comprises the light-emitting diode epitaxial wafer.
The invention is further illustrated by the following examples:
example 1
The preparation method of the light-emitting diode epitaxial wafer provided by the first embodiment of the invention comprises the following steps of S10-S13:
step S10, providing a patterned sapphire substrate;
step S11, introducing NH with a first preset flow rate at a first preset temperature and a first preset pressure 3 Preprocessing the surface of the patterned sapphire substrate for a first preset time to form a composite layer;
wherein the composite layer is an AlNO composite layer with the thickness of 1nm-10nm.
Specifically, the first preset temperature is 1200 ℃, the first preset pressure is 500Torr, the first preset time is 5min, and the first preset flow is 50L/min.
Step S12, introducing TMGa with a second preset flow rate at a second preset temperature and a second preset pressure, and growing a Ga layer on the composite layer for a second preset time, wherein the first preset temperature is higher than the second preset temperature;
wherein the Ga layer is a Ga crystal grain layer with the thickness of 0.5-5 nm. The second preset temperature is 700 ℃, the second preset pressure is 200Torr, the second preset flow is 50sccm, and the second preset time is 45s.
And S13, sequentially growing an AlGaN buffer layer, an undoped GaN layer, an N-type doped GaN layer, a multiple quantum well layer, an electron blocking layer, a P-type doped GaN layer and a P-type contact layer on the Ga layer.
Specifically, the temperature is regulated to 800-900 ℃, the pressure is regulated to 50Torr-100Torr, and an AlGaN buffer layer with the thickness of 30-200 nm is grown on the Ga layer, wherein the Al component of the AlGaN buffer layer is 0-1.
The temperature is adjusted to 1000 ℃ to 1100 ℃, the pressure is adjusted to 100Torr to 500Torr, and an undoped GaN layer with the thickness of 1 μm to 3 μm is grown on the AlGaN buffer layer.
The temperature is regulated to 1000 ℃ to 1200 ℃, the pressure is regulated to 100Torr to 300Torr, an N-type doped GaN layer with the thickness of 1 mu m to 3 mu m is grown on the undoped GaN layer, wherein the doping agent of the N-type doped GaN layer is silane, and the doping concentration of silicon is 10 19 cm -3 -10 20 cm -3 。
Growing a multi-quantum well layer on the N-type doped GaN layer, wherein the multi-quantum well layer comprises a plurality of quantum well layers and quantum barrier layers which are stacked periodically, the quantum well layer is an InGaN layer, the In component is 0.1-0.5, the thickness of the quantum well layer is 1-4 nm, the growth temperature is 750-850 ℃, and the growth pressure is 50Torr-100Torr; the quantum barrier layer is a GaN layer, the thickness of the quantum barrier layer is 8nm-20nm, the growth temperature is 850-950 ℃, and the growth pressure is 50Torr-100Torr.
And (3) regulating the temperature to 950-1050 ℃, regulating the pressure to 50-100Torr, and growing an electron blocking layer with the thickness of 50-100 nm on the multi-quantum well layer, wherein the electron blocking layer is an AlGaN layer, and the Al component is 0.1-0.5.
The temperature is regulated to 900-1050 ℃, the pressure is regulated to 100Torr-600Torr, a P-type doped GaN layer with the thickness of 30nm-200nm is grown on the electron blocking layer, wherein the doping agent of the P-type doped GaN layer is magnesium cyclopentadienyl, and the doping concentration of magnesium is 10 19 cm -3 -10 20 cm -3 。
And (3) regulating the temperature to 1000-1100 ℃, regulating the pressure to 50-100Torr, and growing a P-type contact layer with the thickness of 10-50 nm on the P-type doped GaN layer, wherein the P-type contact layer is an AlGaN layer, and the Al component is 0-0.3.
And after the epitaxial structure is grown, the temperature of the reaction cavity is reduced, and annealing treatment is performed in a nitrogen atmosphere at 650-850 ℃ for 5-15 min.
Example two
The preparation method of the light-emitting diode epitaxial wafer provided by the second embodiment of the present invention is different from the preparation method of the light-emitting diode epitaxial wafer in the first embodiment in that:
the first preset temperature is 1000 ℃.
Example III
The preparation method of the light-emitting diode epitaxial wafer provided by the third embodiment of the invention is different from the preparation method of the light-emitting diode epitaxial wafer in the first embodiment in that:
the first preset temperature is 1100 ℃.
Example IV
The fourth embodiment of the present invention provides a method for preparing a light emitting diode epitaxial wafer, which is different from the method for preparing a light emitting diode epitaxial wafer in the first embodiment in that:
the first preset temperature is 1300 ℃.
Example five
The fifth embodiment of the present invention provides a method for manufacturing a light emitting diode epitaxial wafer, which is different from the method for manufacturing a light emitting diode epitaxial wafer in the first embodiment in that:
the first preset pressure is 300Torr.
Example six
The method for preparing a light emitting diode epitaxial wafer according to the sixth embodiment of the present invention is different from the method for preparing a light emitting diode epitaxial wafer according to the first embodiment in that:
the first preset pressure is 400Torr.
Example seven
The seventh embodiment of the present invention provides a method for preparing a light emitting diode epitaxial wafer, which is different from the method for preparing a light emitting diode epitaxial wafer in the first embodiment in that:
the first preset pressure is 600Torr.
Example eight
The method for preparing a light emitting diode epitaxial wafer according to the eighth embodiment of the present invention is different from the method for preparing a light emitting diode epitaxial wafer according to the first embodiment in that:
the first preset time is 3min.
Example nine
The preparation method of the light-emitting diode epitaxial wafer provided by the ninth embodiment of the invention is different from the preparation method of the light-emitting diode epitaxial wafer in the first embodiment in that:
the first preset time is 7min.
Examples ten
The tenth embodiment of the present invention provides a method for manufacturing a light emitting diode epitaxial wafer, which is different from the method for manufacturing a light emitting diode epitaxial wafer in the first embodiment in that:
the first preset flow is 30L/min.
Example eleven
The eleventh embodiment of the present invention provides a method for manufacturing a light emitting diode epitaxial wafer, where the method for manufacturing a light emitting diode epitaxial wafer in this embodiment is different from the method for manufacturing a light emitting diode epitaxial wafer in the first embodiment in that:
the first preset flow is 40L/min.
Example twelve
The method for preparing a light emitting diode epitaxial wafer according to the twelfth embodiment of the present invention is different from the method for preparing a light emitting diode epitaxial wafer according to the first embodiment in that:
the first preset flow is 60L/min.
Example thirteen
The preparation method of the light-emitting diode epitaxial wafer provided by the thirteenth embodiment of the present invention is different from the preparation method of the light-emitting diode epitaxial wafer in the first embodiment in that:
the second preset temperature is 650 ℃.
Examples fourteen
The preparation method of the light-emitting diode epitaxial wafer provided by the fourteenth embodiment of the present invention is different from the preparation method of the light-emitting diode epitaxial wafer in the first embodiment in that:
the second preset temperature is 750 ℃.
Example fifteen
The preparation method of the light-emitting diode epitaxial wafer provided by the fifteenth embodiment of the present invention is different from the preparation method of the light-emitting diode epitaxial wafer in the first embodiment in that:
the second preset pressure is 100Torr.
Examples sixteen
The preparation method of the light-emitting diode epitaxial wafer provided by the sixteenth embodiment of the present invention is different from the preparation method of the light-emitting diode epitaxial wafer in the first embodiment in that:
the second preset pressure is 300Torr.
Example seventeen
The method for preparing a light emitting diode epitaxial wafer according to the seventeenth embodiment of the present invention is different from the method for preparing a light emitting diode epitaxial wafer according to the first embodiment in that:
the second preset time is 30s.
Example eighteen
The eighteenth embodiment of the present invention provides a method for manufacturing a light emitting diode epitaxial wafer, where the method for manufacturing a light emitting diode epitaxial wafer in this embodiment is different from the method for manufacturing a light emitting diode epitaxial wafer in the first embodiment in that:
the second preset time is 60s.
Examples nineteenth
The nineteenth embodiment of the present invention provides a method for manufacturing a light emitting diode epitaxial wafer, where the method for manufacturing a light emitting diode epitaxial wafer in this embodiment is different from the method for manufacturing a light emitting diode epitaxial wafer in the first embodiment in that:
the second preset flow is 25sccm.
Example twenty
The twentieth embodiment of the present invention provides a method for preparing a light emitting diode epitaxial wafer, where the method for preparing a light emitting diode epitaxial wafer in this embodiment is different from the method for preparing a light emitting diode epitaxial wafer in the first embodiment in that:
the second preset flow is 75sccm.
Comparative example one
The preparation method of the light-emitting diode epitaxial wafer provided by the first comparative example is different from the preparation method of the light-emitting diode epitaxial wafer in the first embodiment in that:
blank group, no composite layer and Ga layer.
Comparative example two
The preparation method of the light-emitting diode epitaxial wafer provided by the second comparative example of the present invention is different from the preparation method of the light-emitting diode epitaxial wafer in the first embodiment in that:
only the composite layer, no Ga layer.
Comparative example three
The preparation method of the light-emitting diode epitaxial wafer provided by the second comparative example of the present invention is different from the preparation method of the light-emitting diode epitaxial wafer in the first embodiment in that:
only the Ga layer and no composite layer.
Referring to table 1 below, the parameters corresponding to the above-mentioned first to twenty examples and the comparative examples one to three are shown.
TABLE 1
It should be noted that examples one to twenty and comparative examples one to three were prepared as 12mil by 20mil chips using the same process conditions, and tested for performance at 100mA current.
The XRD takes the half-width of 002/102 crystal face to represent the crystal quality of the chip, and the narrower the half-width is, the better the crystal quality is, and the surface roughness is measured within the range of 5 mu m multiplied by 5 mu m.
It is known from the data of the first to third comparative examples that dislocation and warpage can be effectively reduced and the crystal quality of the epitaxial layer can be improved by growing the composite layer and the Ga layer.
As can be seen from the data of the first to fourth embodiments, when the first preset temperature is too high, the structure of the patterned sapphire substrate is damaged, so that cracks exist on the surface of the patterned sapphire substrate, the effect of the patterned sapphire substrate is weakened, and the quality of the subsequently grown epitaxial layer crystal is reduced; when the first preset temperature is too low, NH 3 Low cracking rate, N 3+ Insufficient AlNO compound layers cannot be formed, so that the quality of the epitaxial layer crystal grown later is not obviously improved.
As can be seen from the data of the first embodiment, the fifth embodiment and the seventh embodiment, when the first preset pressure is too high, the structure of the patterned sapphire substrate is damaged, so that cracks exist on the surface of the patterned sapphire substrate, the effect of the patterned sapphire substrate is weakened, and the quality of the subsequently grown epitaxial layer crystal is reduced; when the first preset pressure is too low, NH 3 Low cracking rate, N 3+ Insufficient, the AlNO composite layer formed is too thin to achieve the desired effect.
As can be seen from the data of the first, eighth and ninth embodiments, when the first preset time is too long, the patterned sapphire substrate is corroded, resulting in degradation of the crystal quality of the subsequently grown epitaxial layer; when the first preset time is too short, NH 3 Short cracking time, N 3+ Insufficient, the AlNO composite layer formed is too thin to achieve the desired effect.
As can be seen from the data of the first embodiment, the tenth embodiment to the twelfth embodiment, when the first preset flow is too large, the patterned sapphire substrate is corroded, so that the quality of the epitaxial layer crystal grown subsequently is reduced; when the first preset flow is too small, cracking N 3+ Insufficient, the AlNO composite layer formed is too thin to achieve the desired effect.
As can be seen from the data of the first, thirteenth and fourteen embodiments, when the second preset temperature is too low, the diffusion rate of Ga grains on the surface of the composite layer is slow, resulting in uneven distribution of Ga grains in the Ga grain layer, and thus the quality of the subsequently grown epitaxial layer crystal is reduced; when the second preset temperature is too high, the Ga grains grow too fast, resulting in Ga grain clusters, which cause a decrease in the quality of the subsequently grown epitaxial layer crystals.
As can be seen from the data of the first, fifteen and sixteenth embodiments, the second preset pressure is not significantly affected by the excessive pressure.
As can be seen from the data of the first embodiment, the seventeenth embodiment and the eighteenth embodiment, when the second preset time is too long, the middle Ga grains of the Ga layer grow better, but the larger the warpage is, the more convex the warpage is, resulting in cracking of the surface of the epitaxial layer that grows subsequently; when the second preset time is too short, ga grains in the Ga layer grow unevenly and warp is concave, so that cracks are generated on the surface of the epitaxial layer which grows later.
As can be seen from the data of the first, nineteenth and twenty embodiments, when the second preset flow rate is too large, the Ga grains in the Ga layer grow better, but the warpage is also larger, so that cracks are generated on the surface of the epitaxial layer which is grown subsequently; when the second preset flow is too small, the Ga grains in the Ga layer grow unevenly, and the quality of the subsequently grown epitaxial layer is not obviously improved.
In conclusion, dislocation and warpage can be effectively reduced by growing the composite layer and the Ga layer, and the crystal quality of the epitaxial layer is improved.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the 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 embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing examples illustrate only a few embodiments of the invention, and are described in detail, but are not to be construed as limiting the scope of the invention. It should be noted that it is possible for those skilled in the art to make several variations and modifications without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (10)
1. The preparation method of the light-emitting diode epitaxial wafer is characterized by comprising the following steps of:
providing a patterned sapphire substrate;
introducing NH with a first preset flow rate at a first preset temperature and a first preset pressure 3 Preprocessing the surface of the patterned sapphire substrate for a first preset time to form a composite layer;
introducing TMGa with a second preset flow rate at a second preset temperature and a second preset pressure, and growing a second preset time on the composite layer to form a Ga layer, wherein the first preset temperature is higher than the second preset temperature;
and an AlGaN buffer layer, an undoped GaN layer, an N-type doped GaN layer, a multiple quantum well layer, an electron blocking layer, a P-type doped GaN layer and a P-type contact layer are sequentially grown on the Ga layer.
2. The method of manufacturing a light emitting diode epitaxial wafer according to claim 1, wherein the first preset temperature is 1000 ℃ to 1200 ℃ and the second preset temperature is 650 ℃ to 750 ℃.
3. The method for manufacturing a light emitting diode epitaxial wafer according to claim 1, wherein the first preset flow is 30-50L/min and the second preset flow is 50-100 sccm.
4. The method for manufacturing a light emitting diode epitaxial wafer according to claim 1, wherein the first preset pressure is 100Torr to 200Torr and the second preset pressure is 100Torr to 200Torr.
5. The method for preparing a light-emitting diode epitaxial wafer according to claim 1, wherein the first preset time is 1min-5min, and the second preset time is 30s-60s.
6. The method for manufacturing a light-emitting diode epitaxial wafer according to claim 1, wherein the composite layer is an AlNO composite layer and the Ga layer is a Ga grain layer.
7. The method for manufacturing a light-emitting diode epitaxial wafer according to claim 1, wherein the growth temperature of the AlGaN buffer layer is 800-900 ℃ and the growth pressure is 50-100 Torr.
8. A light-emitting diode epitaxial wafer, characterized in that the light-emitting diode epitaxial wafer is prepared by the preparation method of any one of claims 1 to 7, the light-emitting diode epitaxial wafer comprising:
patterning the sapphire substrate;
the composite layer, the Ga layer, the AlGaN buffer layer, the undoped GaN layer, the N-type doped GaN layer, the multiple quantum well layer, the electron blocking layer, the P-type doped GaN layer and the P-type contact layer are sequentially laminated on the patterned sapphire substrate.
9. The light-emitting diode epitaxial wafer according to claim 8, wherein the composite layer is an AlNO composite layer with a thickness of 1nm to 10nm, the Ga layer is a Ga grain layer, and the grain size is 0.5nm to 5nm.
10. A light emitting diode comprising the light emitting diode epitaxial wafer of any one of claims 8 or 9.
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