Study of segregation inhomogeneities in LEC GaAs by means of DSL Photoetching and EBIC measurements

Selective photoetching in HF-CrO3 aqueous solutions (DSL method: diluted Sirtl-like etching with the use of light) and energy-dependent electron beam induced current (EBIC) have been employed to study segregation inhomogeneities m LEC grown n-type GaAs. The relationship between relative DSL etch depth and dopant concentration across growth striations has been established by means of local EBIC measurements of dopant concentration. It has been found that greater etch depths correspond to smaller dopant concentrations over a dopant concentration range of about one decade. These results are in agreement with the electrochemical model of GaAs etching in a DSL etching system, and can be explained in terms of surface recombination of the photogenerated carriers and cathodic protection.