Method for producing air-gap structure by selective etching aluminum arsenide using dilute hydrochloric acid

Abstract

The invention relates to a method for manufacturing an air gap structure by using dilute hydrochloric acid to selectively corrode an aluminum arsenide sacrificial layer, which comprises the following steps: a, growing a structure with the aluminum arsenide sacrificial layer on a gallium arsenide substrate by using a molecular beam epitaxial technique, and arranging a distributed Bragg reflector consisting of gallium arsenide and aluminum gallium arsenide on the aluminum arsenide sacrificial layer; b, photoetching a required graph on the surface of a wafer, non-selectively and vertically corroding a table top on the surface of the wafer, and exposing the side wall of the aluminum arsenide sacrificial layer; c, selectively corroding the aluminum arsenide sacrificial layer on the wafer by dilute hydrochloric acid in a thermostatic water bath; d, transferring the selectively corroded wafer to a beaker filled with methanol or acetone by a special polyfluorin porcelain perforated ladle, and cleaning the wafer; e, keeping the beaker filled with the methanol or the acetone standing in a constant temperature environment until the methanol or the acetone fully volatilizes, and taking out the wafer; and f, measuring the depth of corroding the aluminum arsenide at the side of the dilute hydrochloric acid, and estimating average rate of corroding the aluminum arsenide at the side of the dilute hydrochloric acid to obtain the required air gap structure.

Description

technical field [0001] The invention relates to the technical field of micromachining, and is a method for making an air-gap structure by utilizing the difference in corrosion rate of dilute hydrochloric acid solution to gallium-aluminum arsenide series materials with different aluminum contents to realize selective corrosion of aluminum arsenide sacrificial layer method. The invention can be used to make GaAs-based optoelectronics such as MEMS (micro-mechanical systems) wavelength-tunable vertical cavity optical filters, MEMS wavelength-tunable vertical cavity surface-emitting lasers, and MEMS wavelength-tunable resonator-enhanced photodetectors. device. Background technique [0002] With the development of a new generation of high-capacity and high-speed optical communication systems, dense wavelength division multiplexing technology has played an increasingly important role in optical communication. With the increase of the number of channels of different wavelengths in...

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Problems solved by technology

The selective etching of the sacrificial layer is accomplished by lateral etching. Therefore, when the gallium arsenide sacrificial layer is etched by a dry method, the etching rate is too slow, the time required is too long, and a thick layer must be used. mask to protect the mesa from being etched vertically

Selectively corroding the aluminum arsenide sacrificial layer with hydrofluoric acid solution will leave a reaction residue that is not easy to remove on the upper surface of the substrate, which will affect the optical performance of the surface. The aluminum arsenide sacrificial layer between two mirrors is used The method of selective etching after complete oxidation to alumina makes the process more complicated

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