FAST GROWTH OF HYDROGENATED AMORPHOUS-SILICON FROM DICHLOROSILANE

We report the discovery of very high growth rates of hydrogenated amorphous silicon (a-Si:H) from a glow discharge in dichlorosilane (SiH2Cl2) with small additions of silane (SiH4). The growth rate reaches approximately 50 angstrom s-1 at substrate temperatures between 200 and 300-degrees-C. The rate depends on substrate temperature and is correlated with the concentrations of hydrogen and chlorine in the films in a way that suggests a SiH4-catalyzed mutual elimination of Cl and H from the growing surface. We observe no dust, and no growth on the cold walls of the chamber. The film properties suggest material close to device quality, with dark conductivities of approximately 10(-12) S cm-1 and photoconductivities of approximately 10(-7) S cm-1. We measured a midgap defect density of 3.3 x 10(16) cm-3 in an as-grown film, and 4.5 x 10(16) cm-3 after 73 h of light soaking at 1 W cm-2. (C) 1994 American Institute of Physics.