Properties and device applications of hydrogenated amorphous silicon carbide films

Abstract

Hydrogenated amorphous silicon carbide (a-SiC:H) films were deposited with a radio-frequency plasma-enhanced chemical vapor deposition system which utilizes a dc electric field applied independently of the inductively coupled rf field. The source gases were SiH4 and CH4. It was found that application of an electric field directed out of the substrate surface enhances the growth rate and yields some improvements in photoconductivity. The compositions of the films were evaluated by x-ray photoelectron spectroscopy for a range of source gas mixtures. In order to assess the applicability of a-SiC:H thin films, heterojunction a-SiC:H/crystalline Si (c-Si) diodes were fabricated and their electrical characteristics evaluated. The diode capacitance-voltage results confirmed a step junction, which was consistent with the abruptness of the interface demonstrated by high-resolution transmission electron microscopy. The heterojunction diodes also showed good rectifying properties, suggesting promise for a-SiC@B: H in device applications.