XPS and HAXPES analyses for pre-sputtered InP surface and InP/Pt interface

Abstract The state of the pre-sputtered indium phosphide (InP) surface was analyzed by X-ray photoelectron spectroscopy, employing synchrotron-based relatively low-energy X-ray. It was found that the pre-sputtering treatment induced the phosphorus vaporization and made the surface composition In-rich, which was thought to promote oxidation of InP surface in atmosphere. The state of the interface between InP and Pt was also investigated nondestructively, by using hard X-ray photoemission spectroscopy. As a result, it was demonstrated that the interfacial layer was composed of the native oxide (In–O, P–O) and metallic state (In–Pt or In–In, P–P) and that the pre-sputtering treatment increased significantly the amount of the P–O, In–Pt or In–In, and P–P. From a simplified calculation, assuming a Pt/In–Pt/In–P layer stacking structure and neglecting the In–O and P–O components, the thickness of the interfacial layer was estimated to be approximately 3.0 nm.