GaN-based LED epitaxial structure capable of improving carrier injection efficiency, and growth method thereof

Abstract

The invention discloses a GaN-based LED epitaxial structure capable of improving the carrier injection efficiency, and a growth method thereof. A light-emitting layer is formed by barrier layers and quantum well layers alternately, the last barrier layer adopts an Al component, namely an AlxGa1-xN barrier layer with x value gradually changing from 0 to 0.15, other barrier layers are GaN barrier layers, a sub-well layer adopts an InyGa1-yN quantum well layer, and y is 0.1 to 0.3. According to the invention, the growth of the AlGaN electron barrier layer is removed, the improvement of a hole barrier caused by p-type Mg doped AlGaN can be reduced, the serious lattice defect and large stress caused by the growth of the AlGaN and the high-temperature damage of the high-temperature growth condition of the AlGaN to a light-emitting layer structure are reduced, the chip quality is improved, and the AlxGa1-xN barrier layer with gradually changed Al components is adopted, the effect of effectively improving the electron potential barrier can still be achieved, meanwhile, the hole potential barrier can be effectively reduced, electron leakage is restrained, and the hole injection capacity isfurther improved, so the effective radiation recombination rate in the light-emitting layer is increased, and the light-emitting efficiency of the GaN-based LED is improved.

Description

technical field [0001] The invention relates to the field of LED design and application, in particular to an LED epitaxial layer structure and a growth method thereof with improved hole injection layer and light emitting layer structures. Background technique [0002] GaN-based LED is currently one of the main light sources for forming white light. It has the advantages of long life and low energy consumption. However, with the requirements of the working environment, GaN-based LEDs are increasingly required to work under high current. The result is that GaN-based LEDs have a large efficiency attenuation under high current. In the current research, electron leakage is an important reason for the efficiency decay, which is due to the higher effective mass of holes relative to electrons, so that the hole injection from the p-type layer to the active region is more than the electron injection from the n-type layer. The injection efficiency is much lower, so a large number of c...

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Problems solved by technology

[0002] GaN-based LED is currently one of the main light sources for forming white light. It has the advantages of long life and low energy consumption. However, with the requirements of the working environment, GaN-based LEDs are increasingly required to work under high current. The result is that GaN-based LEDs have a large efficiency attenuation under high current

In the current research, electron leakage is an important reason for the efficiency decay, which is due to the higher effective mass of holes relative to electrons, so that the hole injection from the p-type layer to the active region is more than the electron injection from the n-type layer. The injection efficiency is much lower, so a large number of carriers accumulate in the last quantum well near the p-type layer, causing most of the electrons to leak to the p-type layer.

[0003] In this regard, the current GaN-based LED epitaxial growth method uses the method of growing an AlGaN electron blocking layer to effectively increase the height of the effective barrier of the p-side energy band of the light-emitting layer, which can effectively suppress electron leakage through energy band engineering. But at the same time, the hole barrier brought by the AlGaN electron blocking layer also reduces the injection of holes from the p-electrode to the light-emitting layer to a certain extent, which limits the improvement of the luminous efficiency of GaN-based LEDs; on the other hand, the AlGaN electron blocking layer The p-type Mg doping activation rate in the layer is low, and with the increase of Al composition, severe lattice defects and large stress will distort the energy band of the light-emitting layer, further limiting the ability of hole injection into the light-emitting layer

[0004] However, in the face of the high photoelectric efficiency requirements of GaN-based LEDs, the industry still grows AlGaN electron blocking layers in epitaxial growth to avoid the occurrence of lower electron barriers in the energy band of the light-emitting layer due to the lack of a p-AlGaN layer. It will further lead to a large amount of electron leakage, resulting in serious photoelectric efficiency attenuation

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