Gallium arsenide and aluminum gallium arsenide reactive ion etching in boron trichloride/argon mixtures

Abstract

GaAs and Al0.3Ga0.7As were reactive ion etched in a mixture of boron trichloride and argon. The effects of the independent variables such as the time, power, pressure, and gas composition on the etch depth as well as the quality of the resulting etched surfaces were analyzed through a multiple linear regression approach. This provided second-order equations with an excellent ability to describe experimental results. The etching conditions for GaAs and AlGaAs were compared and optimum parameters for equal rate etching of GaAs/Al0.3Ga0.7As layers with straight walls were obtained. These were then sucessfully applied to the high-resolution structuring of multiple quantum well layers, and structures as small as 40 nm were etched. The addition of oxygen to the etch gas produced a high-quality etch for GaAs with >5:1 rate selectivity over Al0.3Ga0.7As.