Interface formation between GaS and CVD diamond films

Thin GaS films were deposited on B-doped diamond (as-grown) and on oxygen-a nnealed B-doped diamond (O-ann.) films grown by plasma-assisted chemical va por deposition on p(+)-type Si(001) substrate and the interface formation h as been characterized by Auger electron spectroscopy (AES), low-energy elec tron-loss spectroscopy (LEELS) and X-ray photoelectron spectroscopy (XPS). The thermal evaporation of a GaS single crystal is used for the deposition. LEELS spectra taken at low E-p (less than or equal to 200 eV) indicate tha t the surface-related peaks are dominant for both as-grown and O-ann. films . Whereas, Surface- and bulk-plasmon peaks of diamond are dominant in the L EELS spectra taken at high E-p for both as-grown and O-ann. films. After th e deposition of GaS at 500-550 degrees C, some new loss peaks consisting of superposition of the peaks due to GaS appear in the LEELS spectra for both as-grown and O-ann. films. XPS spectra indicate a downward band bending du e to oxygen treatment. The downward band bending decreases as a result of G aS deposition and increases as a result of post-annealing at higher tempera ture. C-S and C-Ga bonds are observed for GaS-deposited diamond films. Seco ndary electron emission spectra indicate that the S-terminated diamond film s seem to possess a positive electron affinity surface. (C) 2000 Elsevier S cience B.V. All rights reserved.