Amorphoussiliconfilmsarepreparedatlowertemperatureof350℃bynewcatalyticchemicalvapordepositionmethod.Inthemethod,materialgases(SiH4andH2)aredecomposedbycatalyticreactionatgiventemperature,soa-Sifilmsaredepositedonsubstrates.Itisfoundthata-Sifilmswithhighqualitycanbeobtain,suchashighphotosensitivityof10^6,lowspindensityof2.5×10^16cm^-3.