Epitaxial structure of gallium nitride based laser device and manufacturing method of epitaxial structure

Abstract

The invention discloses a preparation method of an epitaxial structure of a gallium nitride based laser device, comprising the following steps of: (a) epitaxially growing one GaN buffer layer on a substrate; (b) epitaxially growing an n-type light limiting layer on the buffer layer; (c) growing a lower waveguide layer; (d) epitaxially growing an InaGa1-aN / GaN multi-quantum well as an active region; after growing the last InaGa1-aN / GaN multi-quantum well, replacing the last GaN barrier layer by an AlGaN layer, wherein the AlGaN layer is an AlxGa1-xN which is 1-50 nm in thickness and has gradually-changed Al components or is composed of at least two layers of AlyGa1-yN layers with gradually-increased Al components; (e) epitaxially growing one p-type AlzGa1-zN electron blocking layer, wherein in the steps (d) and (e), x is more than or equal to 0 and is less than or equal to y, y is more than or equal to x and is less than or equal to z, and z is more than or equal to y and is less than or equal to 1; (f) growing an upper waveguide layer; (g) growing a p-type light limiting layer; and (h) growing an ohm contact layer. According to the preparation method provided by the invention, the problem of electron accumulation of the uppermost GaN barrier layer and an AlGaN electron blocking layer is solved, and the performance of the laser device is effectively improved.

Description

technical field [0001] The invention relates to a GaN-based laser epitaxial structure and a preparation method thereof, belonging to the field of laser structure design in semiconductor technology. Background technique [0002] In the prior art, GaN-based lasers (LDs) and light-emitting diodes (LEDs) both use a single layer of Al with a fixed Al component. x Ga 1-x N (usually x~0.2) acts as an electron blocking layer. However, for the III-V nitride epitaxial structure grown on the (0001)c polar plane, the GaN barrier layer (hereinafter referred to as the uppermost GaN barrier layer) in the traditional quantum well active region is closest to the p-type layer. There will be a sudden change in the composition between AlGaN and the AlGaN electron blocking layer. The sudden change in the composition will lead to changes in the potential distribution and electronic band structure, resulting in a large built-in polarization electric field and electron accumulation on the interfa...

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Problems solved by technology

However, for the III-V nitride epitaxial structure grown on the (0001)c polar plane, the GaN barrier layer (hereinafter referred to as the uppermost GaN barrier layer) in the traditional quantum well active region is closest to the p-type layer. There will be a sudden change in composition between AlGaN and AlGaN electron blocking layers, which will lead to changes in potential distribution and electronic band structure, resulting in a large built-in polarization electric field and electron accumulation on the interface; and electron accumulation It will cause non-radiative recombination or overflow the active area, and may also increase the light absorption of the laser as an absorption area, these effects will reduce the performance of the laser

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