a-SiOx:H (hydrogenated amorphous silicon oxide) has been successfully deposited by means of HW-CVD. Different amounts of oxygen involved a-Si:H deposition feasibility were explored using catalytic reaction process. Pure silane, hydrogen and oxygen gases were introduced through coiled tungsten catalyst. Material deposition was carried out on glass and C-Si Substrates at 200 degrees C. The calculated optical bandgap value increases with the oxygen to silane gas flow ratio from 1.87 to 2.1 eV, which is related to the oxygen content, as corroborated by FTIR analysis. FTIR mainly revealed Si-O-Si and O-Si-H related bonds. The tungsten catalyst has no appreciable degradation after several sample preparations. (c) 2005 Elsevier B.V. All rights reserved.