Influence of the Surface Depletion Layer on the Photoetching Rate at Growth Striations in LEC GaAs

Quantitative energy-dependent EBIC measurements have been used to calibrate the photoetching rate in HF-CrO3 aqueous solutions (DSL method: Diluted Sirtl-like etching with the use of Light) as a function of dopant concentration in LEC grown n-type GaAs samples containing growth striations. The relative DSL etching rate depends on the width of the surface depletion region associated with the semiconductor-etching solution interface, i. e. greater etch rates correspond to smaller dopant concentrations. These results are in agreement with the electrochemical model of GaAs etching in the DSL etching system.