Oxidation of In xGa 1- xAs yP 1- y by NO 2 studied with Auger electron spectroscopy

We have studied the oxidation of quaternary InGaAsP materials by NO ₂, using Auger electron spectroscopy for both elemental and chemical analysis of the surface. We report that NO ₂ induces a preferential oxidation, forming oxides of Ga, In, and P. The As remains unoxidized. From Ar ⁺ ion milling we find that the oxide layers are fairly thin (less than 10 Å), even at high exposures (greater than 1000 L) of NO ₂, where we obtain a saturation coverage of approximately 0.3 ML (monolayers). We have also measured electron energy loss spectra (EELS) and observe the disappearance of the surface plasmon loss feature upon oxide formation.