X-ray photoelectron spectroscopy and Auger electron spectroscopy studies of glow discharge Si_1-xC_x:H films

Abstract

X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) were used to characterize the air-exposed and sputter-cleaned surfaces of glow-discharge-produced Si1-xCx:H (x=0.05 to 0.90) films. On the air-exposed surfaces, silicon was preferentially oxidized with the enriched carbon existing as graphite or hydrocarbon. Signal intensities obtained from the surfaces sputter cleaned with 1 keV Ar+ ion beams indicated no significant preferential sputtering of C to Si for these films. The values of the carbon 1s and silicon 2p and 2s binding energies as well as the valence band spectra suggested a significant change in the local atomic configurations at x∼0.6-0.7. Based on these XPS and AES results and the reported IR absorption data, a slightly cross-linked, carbon and hydrogen substituted polysilicon and an almost fully cross-linked, silicon and hydrogen substituted polycarbon were proposed to describe the structure of films below and above x∼0.6-0.7, respectively.