Change in crystalline morphologies of polycrystalline silicon films prepared by radio‐frequency plasma‐enhanced chemical vapor deposition using SiF4+H2 gas mixture at 350 °C

Polycrystalline silicon films have been deposited on glass substrates at 350 °C by radio‐frequency plasma‐enhanced chemical vapor deposition using a SiF4+H2 gas mixture. Crystalline fraction decreased abruptly with increasing gas flow ratio. Film structure drastically changed by increasing gas pressure from 0.4 to 2.0 Torr. At lower gas pressure, columnar crystals 30 nm in diameter grew from the glass substrates, while at higher gas pressure larger columnar crystals with a maximum diameter of approximately 100 nm grew on an amorphous Si layer approximately 170 nm thick.