Chemistry and physics of silicon-based amorphous semiconductors

This report summarizes the work done under a multi-phased IBM subconstract with the Solar Energy Research Institute. A major thrust of this research was HOMOCVD film growth. This phase of the work concentrated on material properties of a-Si:H and a-Ge:H, and a comparison of these properties with films produced by the glow discharge process. Measurements suggest that HOMOCVD films are less disordered than plasma-deposited a-Si:H, with other material properties being comparable. Schottky barrier devices were made with HOMOCVD a-Si:H, and an external J/sub sc/ of 6 mA/cm/sup 2/ under AM 1 was measured, along with a V/sub oc/ of 508 mV. A diffusion length of 0.4 ..mu..m was estimated from quantum efficiency measurements. Some discussion of plasma physics in a HOMOCVD deposition process is presented. Other areas of research investigated under this contract are window-type materials prepared from silane-phenylsilane mixtures and theoretical investigations of the causes of disorder in a-Si:H.