SULFUR CONTAMINATION OF (100)GAAS RESULTING FROM SAMPLE PREPARATION PROCEDURES AND ATMOSPHERIC EXPOSURE

X-ray photoelectron spectroscopy with argon ion depth profiling was em ployed to investigate sulfur deposition from a standard 3H(2)SO(4):H2O 2:H2O etchant onto (100) GaAs. From these experiments it appears that etching with 3H(2)SO(4):H2O2:H2O leaves a mixed sulfide/oxide layer, w ith free sulfur at the top surface of this layer. The sulfide within t he layer was found to be bound to gallium, and recognition of the pres ence of sulfur allowed the clarification of the Ga(3d) photoelectron p eak position for Ga2O3. No evidence of sulfate formation was found. Re moval of the sulfur contamination using a solution of HCl:H2O was inve stigated. Also, atmospheric contamination of samples exposed to room c onditions for six months was observed. (C) 1996 American Vacuum Societ y.