Oxidation and Carbon Contamination in GaAs (100) Wet Treatments

Abstract

ABSTRACTOxidation and carbon contamination of n-type GaAs (100) surfaces have been investigated by x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and secondary ion mass spectroscopy (SIMS) for a variety of cleaning and etching pretreatment procedures prior to immersion in either (NH4)2S, Na2S aqueous solutions or S2Cl2 solution in dichloromethane. The study has shown that sulfur passivation removes surface oxide and minimize carbon contamination for surfaces treated in (NH4)2S and S2Cl2 solutions. A significant oxygen and carbon contamination in the anodic passivation of GaAs (100) in (NH4)2Sx aqueous solution have been quantitatively measured. In addition, pretreatment in basic solutions have shown minimal oxygen and carbon level in comparison with the acidic solutions. Surface pretreatment carried out ex-situ has shown a higher risk of surface contamination prior to sulfur passivation.