Microcrystalline silicon films fabricated by bias-assisted hot-wire chemical vapor deposition

Microcrystalline silicon films (mu c-Si:H) were deposited on stainless steel substrates by bias-assisted hot-wire chemical vapor deposition. The effect of substrate bias and substrate temperature on the crystallinity of mu c-Si:H films was studied by Raman spectroscopy, X-ray diffraction and scanning electron microscopy. The results show that both the Raman peak position and the crystalline fraction of the mu c-Si:H films deposited at 200 A degrees C were obviously improved by introducing -800 V substrate bias. The films deposited at 200 A degrees C with -800 V substrate bias show strongly sharpened Si (111) peak together with Si (220) and Si (311) peaks, which was different from a weak Si (111) peak for those deposited without substrate bias. By increasing the substrate temperature from 200 to 300 A degrees C, while keeping the substrate bias at -800 V, the crystallinity of the silicon films was further improved, and mu c-Si:H films with crystalline fraction of 74 % was obtained.