Nucleation and growth of silicon on ceramic substrates by RTCVD at atmospheric pressure

Abstract
Thin-film solar cells from silicon on insulating substrates (SOI) are a serious option to reduce the cost and silicon production mass. Here we investigated nucleation and growth of silicon on alumina and mullite ceramics in a lamps-heating assisted CVD reactor working at atmospheric pressure with trichlorosilane as a precursor gas. The nucleation density and the structural quality of the deposited Si layers were analyzed as a function of the deposition conditions and the structure and composition of the ceramic substrate. The results were compared with the well-known growth mechanism of silicon on amorphous substrates like SiO₂. Optimal conditions allowed deposition of 20-30µm thick polycrystalline silicon with grains up 15µm in size and <110> oriented. These layers are very suitable for solar cells processing.