Effects of deposition parameters on crystallization of PECVD amorphous silicon films

Plasma-enhanced chemical vapor deposition was used to deposit a-Si:H thin films (approx. 1000 angstrom) at various temperatures below 300°C on Corning 7059 glass substrates using a silane-based plasma. These films were used as precursor materials to produce solid phase crystallized polycrystalline silicon (poly-Si) by conventional furnace annealing at 600°C in N₂ ambient. The precursor a-Si and final poly-Si films were examined using spectroscopic ellipsometry and transmission electron microscopy. Precursor film deposition temperatures were found to affect the void density in the a-Si film and grain size in the resulting poly-Si film with lower deposition temperatures leading to higher void density in the a-Si film and larger grain size in the poly-Si film.