Ultraviolet distributed Bragg mirror based on porous AlGaN and preparation method thereof

Abstract

The invention relates to an ultraviolet distributed Bragg mirror based on porous AlGaN and a preparation method thereof. The ultraviolet distributed Bragg mirror based on porous AlGaN includes a substrate, a nucleation layer, a buffer layer, a stress regulation layer, and Alx(Ga1-x)N layers and porous Aly(Ga1-y)N layers which are in a multi-cycle alternately stacking mode. The invention further provides the preparation method of the ultraviolet distributed Bragg mirror based on the porous AlGaN, the nucleation layer, the buffer layer, the stress regulation layer, and the Alx(Ga1-x)N layers andthe porous Aly(Ga1-y)N layers in a multi-cycle alternately stacking mode are stacked on the substrate, photoelectrochemical etching is then performed, the AlGaN layer is made porous by band gap selectivity of photoelectrochemical reaction, and the ultraviolet distributed Bragg mirror based on the porous AlGaN is formed.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a porous AlGaN-based ultraviolet distributed Bragg reflector and a preparation method thereof. Background technique [0002] The AlGaN-based UV distributed Bragg reflector (Distributed Bragg Reflector, DBR) is the key component of AlGaN-based UV resonant cavity optoelectronic devices (including UV resonant cavity diodes, UV vertical cavity surface emitting laser diodes, UV resonant cavity enhanced detectors, etc.) One of the parts can also be used to enhance the light output of AlGaN-based ultraviolet light-emitting diodes. [0003] AlGaN-based UV DBRs are usually stacked alternately by multi-period AlN layers and AlGaN layers, and are usually epitaxially grown by MOCVD. Since the refractive index difference between the two is very small, more than 30 periods of quarter-wave stacks are generally required ( The thickness of each layer is where λ 0 is the central reflect...

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Problems solved by technology

There are also researches on the preparation of ultraviolet DBR based on electrochemical etching to form porous AlGaN materials, but its Al composition is very low, generally less than 0.3, because the activation energy of n-type doping of AlGaN materials with high Al composition is very high, so the conductivity Poor performance, resulting in more difficult electrochemical etching, lower porosity, difficult to obtain lower refractive index

However, the DBR based on the AlGaN material whose A1 composition is lower than 0.3 can only be used in the UVA band due to the absorption of the material itself.

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