Characterization of etch rate and anisotropy in the temperature-controlled chemically assisted ion beam etching of GaAs

Abstract

Independent adjustment of etch rate and sidewall profiles in chemically assisted ion beam etching (CAIBE) of GaAs is demonstrated by controlling the temperature of the sample. GaAs etch rate data as a function of sample temperature, ion beam flux, and reactive gas flow is presented for CAIBE using a 500 eV argon ion beam and molecular chlorine. At a constant etch rate of 0.5 μm/min, etch profiles ranging from vertical to crystallographically faceted are obtained. This demonstrated flexibility, combined with the inherent reproducibility of dry etching, make CAIBE an attractive choice for processing advanced semiconductor devices. To illustrate the range of capabilities available with temperature-controlled CAIBE, etched-facet laser structures, self-aligned mesas and fine tips suitable for field-emitting devices are fabricated.