Effects of gas temperature on optical and transport properties of a-Si:H films deposited by PECVD

摘要

Effects of silane temperature (Tg) before glow-discharge on the optical and transport properties of hydrogenated amorphous silicon (a-Si:H) thin films were investigated. The optical measurements show that the refractive index increases with increasing Tg. The transport characterizations show that when Tg increases, the dark conductivity increases. However, the temperature coefficient of resistance decreases. In addition, after holding at 130C for 20 h, the resistance variation, R/R, of the films deposited at Tg = room temperature (10.8%) is much larger than those deposited at silane temperatures of 80C (3%) and 160C (2%). This can be attributed to different rates of defect creation in a-Si:H films caused by various Tg.