Deposition of Hydrogenated Amorphous Silicon Carbon Films Using Vacuum Ultraviolet Light

Abstract

Hydrogenated amorphous silicon carbon films are deposited using disilane and acetylene with vacuum ultraviolet light (147nm) emitted from a microwave-excited Xe resonance lamp. The film shows a high photoconductivity of 1.2 × 10⁻⁵S/cm at an optical bandgap of 2.0eV which is one order larger than that of device-quality films deposited by a glow discharge (GD) method. Because of high photoconductivity in this film, over-hydrogenation of carbon atom is avoided, and tetrahedral bondings seem to form rigid random networks. For an application to the window layer of amorphous silicon-alloy solar cells, p-type doping properties are examined. In this case, a photoconductivity of 3.9 × 10⁻⁶S/cm at an optical bandgap of 2.0eV is obtained, which is comparable to that of device-quality films deposited by a GD method.