The use of secondary ion mass spectrometry for studies of oxygen adsorption and oxidation

Thin oxide layers on silicon and tantalum as well as oxygen saturated silicon surfaces have been investigated by means of SIMS. Sputter depth profiling was achieved using a raster scanned 2 keV argon ion beam. The results clearly indicate that oxygen adsorption does not lead to on oxide-like structure. Moreover it is found that air-grown room temperature oxides on silicon are depleted of oxygen as compared to the composition of thick silicon dioxides. The results are discussed with reference to recently reported SIMS studies on oxygen covered surfaces.