Orientation dependent reactive ion etching of GaAs in SiCl₄

The reactive ion etching characteristics of (100) GaAs in SiCl₄ have been investigated. It was found that pronounced orientation dependent etching could be obtained under plasma conditions of low power density and moderate pressures (around 20 m Torr). At very low pressures, structures with vertical sidewalls were obtained. The structures obtained in the orientation dependent etching mode are similar to those obtained by wet etching and those observed in bromine plasma etching. Etch profiles were different along the [011] and [01̄1] orientations and the relation of etch rates in the different planes follows the relation R_〈100〉>R _〈111〉>R_〈100〉.