CN-121985637-A - Forming method of Micro-LED epitaxial structure, epitaxial structure and chip

CN121985637ACN 121985637 ACN121985637 ACN 121985637ACN-121985637-A

Abstract

The application relates to the technical field of semiconductor optoelectronic devices, in particular to a method for forming a Micro-LED epitaxial structure, an epitaxial structure and a chip. The Micro-LED epitaxial structure comprises a multi-quantum well layer between an n-type GaN layer and a p-type GaN layer, wherein the multi-quantum well layer comprises 3-10 repeatedly stacked basic units, each basic unit comprises a quantum well layer and a quantum barrier layer on the quantum well layer, the quantum well layer is an InGaN layer, the quantum barrier layer is a GaN layer, and In the step of forming the multi-quantum well layer, the In component incorporation amount influenced by the process condition when the quantum well layer is formed is gradually reduced In the direction from the n-type GaN layer to the p-type GaN layer. The application can lead the content of In components In different quantum well layers In the multi-quantum well layer of the red light Micro-LED to be consistent, thereby improving the luminous effect of the red light Micro-LED.

Inventors

LIU CHUNYU
BI CHAOXIA
LI PANPAN
LI HONGJIAN
YANG XU
HUANG KAI
Li Jincha
ZHANG RONG

Assignees

厦门大学
嘉庚创新实验室

Dates

Publication Date: 20260505
Application Date: 20260116

Claims (10)

1. The method for forming the Micro-LED epitaxial structure is characterized by comprising the following steps of: providing a semiconductor substrate; forming a multiple quantum well layer between an n-type GaN layer close to the semiconductor substrate and a p-type GaN layer far from the semiconductor substrate; The multi-quantum well layer comprises 3-10 repeatedly stacked basic units, wherein each basic unit comprises a quantum well layer and a quantum barrier layer on the quantum well layer, the quantum well layer is an InGaN layer, and the quantum barrier layer is a GaN layer; in the step of forming the multiple quantum well layer, the In component incorporation amount affected by the process condition at the time of forming the quantum well layer gradually decreases In the direction from the n-type GaN layer to the P-type GaN layer.
2. The method of forming a Micro-LED epitaxial structure of claim 1, wherein, The growth temperature of the base units far away from the n-type GaN layer is higher than that of the base units close to the n-type GaN layer between adjacent base units, and other conditions are the same, so that the In component incorporation amount of the quantum well layer In the base units far away from the n-type GaN layer, which is influenced by process conditions, is smaller than that of the quantum well layer In the base units close to the n-type GaN layer between the adjacent base units.
3. The method of forming a Micro-LED epitaxial structure of claim 1, wherein, In the direction from the n-type GaN layer to the P-type GaN layer, dividing all the basic units into a plurality of basic unit groups, wherein each basic unit group comprises one or more basic units; In the direction from the n-type GaN layer to the P-type GaN layer, the growth temperature of the quantum well layer is gradually increased In the base units of different groups, other conditions are the same, so that the In component incorporation amount In the quantum well layer affected by the process conditions is gradually reduced In the base units of different groups, and the growth temperature of the quantum well layer is the same In the base units of the same group, so that the In component incorporation amount In the quantum well layer affected by the process conditions is the same In the base units of the same group.
4. A method for forming a Micro-LED epitaxial structure according to claim 2 or 3, wherein, The gradual rise of the growth temperature is a gradient temperature rise process.
5. The method of forming a Micro-LED epitaxial structure of claim 1, wherein, In the direction from the n-type GaN layer to the P-type GaN layer, the In component charge amount of the base unit far from the n-type GaN layer is smaller than that of the base unit near the n-type GaN layer between the adjacent base units, and other conditions are the same so that the In component incorporation amount of the quantum well layer In the base unit far from the n-type GaN layer, which is affected by the process conditions, is smaller than that of the quantum well layer In the base unit near the n-type GaN layer between the adjacent base units.
6. The method of forming a Micro-LED epitaxial structure of claim 1, wherein, In the direction from the n-type GaN layer to the P-type GaN layer, dividing all the basic units into a plurality of basic unit groups, wherein each basic unit group comprises one or more basic units; in the direction from the n-type GaN layer to the P-type GaN layer, the amount of In component used for forming the quantum well layer is gradually reduced In the base units of different groups, other conditions are the same, so that the amount of In component used In the quantum well layer affected by the process conditions is gradually reduced In the base units of different groups, and the amount of In component used for forming the quantum well layer is the same In the base units of the same group, so that the amount of In component used In the quantum well layer affected by the process conditions is the same In the base units of the same group.
7. A Micro-LED epitaxial structure formed using the method of forming a Micro-LED epitaxial structure of any one of claims 1-6, comprising: a multiple quantum well layer between the n-type GaN layer close to the semiconductor substrate and the p-type GaN layer far from the semiconductor substrate; The multi-quantum well layer comprises 3-10 repeatedly stacked basic units, wherein each basic unit comprises a quantum well layer and a quantum barrier layer on the quantum well layer, the quantum well layer is an InGaN layer, and the quantum barrier layer is a GaN layer or an AlGaN layer; In content difference In different quantum well layers is 4% or less In a direction from the n-type GaN layer to the P-type GaN layer.
8. The Micro-LED epitaxial structure of claim 7, further comprising: the semiconductor substrate is a sapphire substrate, a Si substrate or a SiC substrate; An AlN buffer layer positioned on the surface of the semiconductor substrate; the GaN buffer layer is an undoped GaN layer and is positioned on the surface of the AlN buffer layer; the n-type GaN layer is a Si-doped GaN layer; wherein the doping concentration of Si is 1X10 18 cm -3 ~5×10 19 cm -3 ; The p-type GaN layer comprises a p-type GaN hole injection layer, a lightly doped p-type GaN layer and a heavily doped p-type GaN layer which are stacked on the multi-quantum well layer; The p-type GaN hole injection layer is a Mg-doped GaN layer; Wherein the doping concentration of Mg is 5 multiplied by 10 18 cm -3 ~2×10 20 cm -3 ; The lightly doped p-type GaN layer is an Mg doped GaN layer; wherein the doping concentration of Mg is 5 multiplied by 10 18 cm -3 ~1×10 19 cm -3 ; the heavily doped p-type GaN layer is an Mg doped GaN layer; Wherein the doping concentration of Mg is 5 multiplied by 10 19 cm -3 ~5×10 20 cm -3 ; the Micro-LED epitaxial structure further comprises: The stress release layer is positioned between the multiple quantum well layer and the N-type GaN layer and comprises an In x Ga (1-x) N layer with a period of 1-30, an undoped GaN layer or a superlattice layer with the N-type GaN layer; The electron blocking layer is positioned between the p-type GaN hole injection layer and the lightly doped p-type GaN layer, and is an Mg doped AlGaN layer.
9. The Micro-LED epitaxial structure of claim 8, wherein, In the multiple quantum well layer, the thickness of the quantum well layer is 2-4 nm, the thickness of the quantum barrier layer is 5-30 nm, and the content of In components In the quantum well layer is 30-50%; the thickness of the AlN buffer layer is 10 nm-30 nm; The thickness of the GaN buffer layer is 0.5-4.5 mu m; The thickness of the n-type GaN layer is 0.5-4 mu m; the thickness of the p-type GaN hole injection layer is 5 nm-30 nm; The thickness of the lightly doped p-type GaN layer is 5 nm-150 nm; The thickness of the heavily doped p-type GaN layer is 2 nm-20 nm; the thickness of the InGaN layer In the superlattice layer of the stress release layer is 1-20 nm, the thickness of the undoped GaN layer or the n-type GaN layer is 2-40 nm, and the In component content of the InGaN layer In the stress release layer is 0.1-30%; the thickness of the electron blocking layer is 5 nm-30 nm.
10. A Micro-LED chip is characterized in that, Comprising a red light Micro-LED epitaxial structure formed using the Micro-LED epitaxial structure forming method of any one of claims 1-6.

Description

Forming method of Micro-LED epitaxial structure, epitaxial structure and chip Technical Field The application relates to the technical field of semiconductor optoelectronic devices, in particular to a method for forming a Micro-LED epitaxial structure, an epitaxial structure and a chip. Background With the widespread application of microdisplay technology in Augmented Reality (AR), virtual Reality (VR) and wearable devices, there is an increasing demand for full-color Micro-LED displays with high brightness, high resolution and high color purity. InGaN-based LEDs have become one of the core technological routes for achieving high performance Micro-LED display due to their excellent thermal stability, high reliability, and potential for achieving monolithic full-color integration. The blue light and green light InGaN LED technologies are mature, but the efficiency and color purity of the red light InGaN LED still do not reach the practical application requirements. In the epitaxial structure of Micro-LEDs, inGaN Quantum Wells (QWs) to achieve red emission require high indium (In) compositions (typically over 30%) to obtain long wavelength (> 625 nm) emission. However, a lattice mismatch of about 11% between InN and GaN in InGaN material systems introduces significant strain and dislocation defects at high indium compositions. Such strain not only reduces crystal quality, but also enhances piezoelectric polarization effects, thereby causing a Quantum Confined Stark Effect (QCSE) to be exacerbated, the overlap of electrons with hole wave functions to be reduced, and the Internal Quantum Efficiency (IQE) to be significantly reduced. One of the effects is that the InGaN layer serving as a quantum well In the multi-quantum well layer is uneven In content distribution, so that the red-light InGaN quantum well system is not ideal In light emitting effect. Therefore, a scheme is needed to solve the problem that the light emitting effect of the red light emitting structure is not ideal due to the Micro-LED epitaxial structure. Disclosure of Invention The application provides a method for forming a Micro-LED epitaxial structure, an epitaxial structure and a chip, and aims to solve the problem that the red light emitting structure has an unsatisfactory light emitting effect due to uneven In content distribution In an InGaN layer serving as a quantum well In the Micro-LED epitaxial structure. In one aspect, the application provides a method for forming a Micro-LED epitaxial structure, which comprises the steps of providing a semiconductor substrate, forming a multiple quantum well layer between an n-type GaN layer close to the semiconductor substrate and a P-type GaN layer far away from the semiconductor substrate, wherein the multiple quantum well layer comprises 3-10 repeatedly stacked basic units, each basic unit comprises a quantum well layer and a quantum barrier layer on the quantum well layer, the quantum well layer is an InGaN layer, the quantum barrier layer is a GaN layer or an AlGaN layer, and In the step of forming the multiple quantum well layer, the In component incorporation amount influenced by process conditions when forming the quantum well layer is gradually reduced In the direction from the n-type GaN layer to the P-type GaN layer. In the method for forming the Micro-LED epitaxial structure, in the step of forming the multi-quantum well layer, the In component incorporation amount influenced by the process condition when the quantum well layer is formed is gradually reduced In the direction from the n-type GaN layer to the P-type GaN layer. The In component incorporation amount influenced by the process conditions is controlled to be gradually reduced, so that uneven In component distribution generated by the influence of CPE on the In component In the process of forming the final product is inhibited, the In component difference In InGaN layers serving as quantum well layers In a Micro-LED epitaxial structure of the final product is smaller and more consistent, stable single-peak red light emission can be maintained under high current density, and the light emitting performance of the red light Micro-LED is improved. In some embodiments of the present application, the growth temperature of the base cell away from the n-type GaN layer is higher than that of the base cell close to the n-type GaN layer between adjacent base cells In the direction from the n-type GaN layer to the P-type GaN layer, and other conditions are the same so that the In-composition incorporation amount In the quantum well layer In the base cell away from the n-type GaN layer affected by the process conditions is smaller than that In the quantum well layer In the base cell close to the n-type GaN layer between adjacent base cells. In some embodiments of the application, all the basic units are divided into a plurality of basic unit groups In the direction from the n-type GaN layer to the P-type GaN layer, each basic unit group c