Physics and Chemistry of Hot-Wire Chemical Vapor Deposition from Silane: Measuring and Modeling the Silicon Epitaxy Deposition Rate

We measure and successfully model the deposition rate (R) of epitaxial Si by hot-wire chemical vapor deposition (HWCVD) onto (100) silicon over a wide range of growth conditions. A deposition rate model based on the fundamentals of gas-filament and gas-substrate interactions is presented; the results are consistent with the observed dependences of R on gas pressure, flow, and filament area. Gas-phase measurements of silane depletion allow calculation of the average radical sticking coefficient from the film deposition rate. Our findings indicate that the epitaxial deposition rate can be increased sufficiently to enable an economical epitaxial film-silicon photovoltaic tech-nology on low-cost foreign substrates. The model can be simply adapted to apply to the HWCVD of amorphous, nanocrystalline, and polycrystalline Si.