Migration of the aluminium enhanced crystal growth process from quartz to glass using EBEP-CVD

The use of aluminium precursor films has already been shown to enhance the as-deposited grain size of silicon films on quartz substrates as grown by electron beam excited plasma chemical vapour deposition (EBEP-CVD). In this paper, the process is successfully migrated from quartz substrates to Corning 1737, low cost glass. The move to low cost substrates is essential for the viability of the process in producing silicon films suitable for low cost photovoltaics. Thin aluminium layers are evaporated onto Corning 1737 substrates prior to EBEP-CVD deposition of silicon at 400-600/spl deg/C. Subsequent analysis by X-ray diffraction shows increases in as-deposited grain sizes up to 40 nm, exceeding results achieved on quartz; without aluminium the as-deposited grain size is around 5 nm. The grain size enhancement is dependant on the silicon deposition temperature and the substrate cleaning regime. There is also an apparent correlation between the silicon aluminium grain sizes.