LED epitaxial wafer, preparation method and semiconductor device

Abstract

The invention discloses a preparation method of an LED epitaxial wafer. The preparation method comprises the following steps: S1, providing a substrate; s2, growing a nitride buffer layer on the substrate; s3, growing a non-doped nitride layer on the nitride buffer layer; s4, growing an n-type nitride layer on the non-doped nitride layer; s5, growing an insertion layer unit on the n-type nitride layer, wherein the insertion layer unit comprises a front nitride insertion layer, an oxide insertion layer and a rear nitride insertion layer which grow in sequence; s6, growing a quantum well light-emitting layer on the insertion layer unit; and S7, growing a p-type layer on the quantum well light-emitting layer. According to the preparation method of the LED epitaxial wafer, electrons are decelerated through a high potential barrier of the oxide insertion layer, injection of the electrons into the light-emitting layer is buffered, recombination of the electrons crossing the light-emitting layer to holes of the p-type layer is reduced, the droop effect under large current is improved, electron diffusion is more uniform through the oxide insertion layer, the electron distribution uniformity of the light-emitting layer is improved, and the light-emitting efficiency is improved. The luminous efficiency is improved, and the epitaxial photoelectric uniformity is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to an LED epitaxial wafer, a preparation method and a semiconductor device. Background technique [0002] GaN-based light-emitting diode (LED) is a semiconductor light-emitting device that has the advantages of long life, low energy consumption, small size, and high reliability. It has played an increasingly important role in large-screen color displays, traffic lights, and lighting. [0003] At present, GaN-based LEDs generally grow epitaxial layers on sapphire substrates, which in turn include low-temperature GaN buffer layers, high-temperature non-doped GaN layers, n-type doped layers, InGaN / GaN multi-quantum well layer light-emitting layers, and p-type AlGaN electron blocking layers. layer, p-type layer. On the one hand, because the mobility of electrons is faster than that of holes, and the concentration of free electrons is higher than that of holes, it is easy to caus...

AI Technical Summary

Problems solved by technology

On the one hand, because the mobility of electrons is faster than that of holes, and the concentration of free electrons is higher than that of holes, it is easy to cause uneven distribution of electrons and holes in the MQW, and the holes are concentrated in the MQW closer to the p-type layer. , the gradual attenuation in the n-type direction is not conducive to the recombination of electrons and holes; on the other hand, due to the high electron concentration and fast migration, electrons are easy to overflow into the p-type layer and recombine with ionized holes in the p-type layer. Reduce the ionization efficiency of holes, and produce non-radiative recombination, reduce the injection efficiency of holes and cause a sudden drop in efficiency, which is more serious under high current working conditions

[0004] At present, it is generally used to increase the Al composition of the p-type AlGaN electron blocking layer and place it between the active region and the hole supply layer to block the overflow of electrons. High Al composition can limit part of the electron overflow to the P-type layer, but AlGaN With the increase of the Al composition, the ionization energy of Mg will increase rapidly and the crystal quality will decrease significantly, resulting in a sharp decrease in the ionization efficiency and concentration of holes, which in turn will cause a decrease in brightness and efficiency; the last quantum barrier of the light-emitting layer and The internal polarization field at the interface between AlGaN electron blocking layers and at the interface between the electron blocking layer and the p-type layer, the electron blocking layer with high aluminum composition will lead to severe energy band bending with sharp peaks at the interface , to prevent holes from being effectively injected into the active region; in addition, under the condition of large current injection, a large number of electrons will overflow to the P-type layer in the AlGaN EBL structure with high Al composition, causing efficiency drop effect, aging and light decay At the same time, as the Al composition increases, the crystal quality of the p-type AlGaN electron blocking layer decreases, and dislocations are enlarged in the p-type layer to form a leakage channel, resulting in increased leakage and poor antistatic ability of the LED, and shortened life.

Images