Investigation of reactive ion etching induced damage in GaAs–AlGaAs quantum well structures

Abstract

We report on the use of a novel technique to study reactive ion etching (RIE) induced damage using multiple quantum wells of 20-, 40-, 60-, and 90-Å widths as in situ probes. Cathodoluminescence (CL) at low temperature, using a finely focused electron beam, allows sensitive determination of the quality of individual quantum wells before and after RIE damage. There is a correspondence between individual luminescence peaks and the depth of the particular quantum well. We can therefore use the CL spectral information to provide a sensitive profile of the depth of RIE induced damage. Various etching conditions and the effects of postetch anneals are examined. Pure Ar sputtering and enhanced chemical etching using CCl2F2/BCl3 at different bias voltages are investigated. Our results reveal that the degree and spatial extent of damage increase with increasing ion energy and decreasing ion mass.