Study of Mesa Etching for Infrared Detector Based on InAs/GaSb Superlattice

Abstract

InAs/GaSb superlattice in infrared detector was grown on GaSb substrates by molecular beam epitaxy technique. Using inductively coupled plasma (ICP) etching technique and Cl2/Ar etching gas, the smooth mesa of the device was formed. The influence of etching time, Cl2 percent and RF power on the etching rate and the surface morphology of InAs bulk, GaSb bulk materials and superlattice were studied. It showed that the etching rate of InAs was lower than that of GaSb and the etching surface was smooth at Cl2 in the range of 20%~40%. The results will benefit to forming ohm contact and decrease surface leakage current in the photovoltaic detector.