Raman study of a-Si:H films deposited by PECVD at various silane temperatures before glow-discharge

The ordering evolution of the amorphous network of a-Si:H thin films with increasing initial silane-gas temperatures was investigated by Raman spectroscopy. The results show that there exists a gradual ordering of the amorphous network, both in the near surface and interior region on increasing the silane-gas temperature. In addition, the increase in the gas temperature leads to an improved ordering of amorphous network on the short and intermediate scales towards the surface of a-Si:H thin films. Post-annealing at 250 °C for 3 h mainly leads to a short and intermediate range improvement in the interior region of the films. Our present results suggest that a-Si:H thin films with better quality could be deposited at higher silane-gas temperature.