AES and XPS Studies of Surface of Al_xGa_1-xAs (110) Treated by Ammonium Sulfide

Abstract

We applied the technique of ammonium sulfide treatment to Al x Ga 1- x As (110) surfaces and investigated the atomic composition of a surface by Auger electron spectroscopy and X-ray photoelectron spectroscopy. It was found that surface oxidation was significantly reduced by the sulfur treatment and that sulfur atoms were mainly bonded to Al atoms in an Al-enriched sample of Al x Ga 1- x As ( x =0.78). The surface compositions of the Al-enriched specimen ( x =0.43, 0.78) were also found to be As-riched as a result of both sulfur treatment and the preferential etching of metallic atoms by an acidic solution, which prevents the initial oxidation of the surface of Al x Ga 1- x As.