Catalytic chemical vapor deposition method to prepare high quality hydro-fluorinated amorphous silicon

Abstract

A new type of chemical vapor deposition method, named ‘‘Catalytic-CVD’’ method, is presented. In the method, deposition gases are decomposed by catalytic or pyrolytic reaction between deposition gases and a heated catalyzer, and films are thermally grown on a substrate at temperatures lower than 300 °C without any help from glow discharge plasma. Hydro-fluorinated amorphous silicon (a-Si:F:H) films are deposited by this method using both a SiF2 and H2 gas mixture and a SiH2F2 and H2 mixture. It is found that a very high quality a-Si:F:H film can be obtained, and for instance, that the photosensitivity for AM-1 of 100 mW/cm2 exceeds 106 and the spin density is as low as 6×1015 cm−3.