Local atomic and electronic structure of oxide/GaAs and SiO2/Si interfaces using high-resolution XPS

The chemical structures of thin SiO2 films, thin native oxides of GaAs (20–30 Å), and the respective oxide–semiconductor interfaces, have been investigated using high-resolution x-ray photoelectron spectroscopy. Depth profiles of these structures have been obtained using both argon ion bombardment and wet chemical etching techniques. The chemical destruction induced by the ion profiling method is shown by direct comparison of these methods for identical samples. Fourier transform data-reduction methods based on linear prediction with maximum entropy constraints are used to analyze the discrete structure in oxides and substrates. This discrete structure is interpreted by means of a structure-induced charge-transfer model (SICT).