Reduction of surface states on GaAs by the plasma growth of oxyfluorides

Abstract

Bonding chemistry predicts that native oxides on GaAs produce intrinsic surface state. Native oxyfluoride dielectric are predicted to be stable and free of bonding defects. We have grown native oxides and oxyfluorides on GaAs by a glow discharge plasma process. Oxide MIS structures always have large densities of fast interface states. We have grown oxyfluoride structures in which surface state effects are reduced by about a factor of 50. ESCA and SIMS analysis of the oxyfluoride dielectric showed a uniform fluorine distribution in thermally annealed samples. X- ray photoemission spectroscopy (XPS) indicate that the molecular components of the glass are GaF3 and AsOF3.