Optical, structural and electrical properties of μc-Si:H films deposited by SiH4+H2

Hydrogenated microcrystalline silicon (μc-Si:H) films were prepared by Plasma Enhanced Chemical Vapor Deposition from a mixture of silane highly diluted in hydrogen. The effect of the silane concentration on the deposition rate and on the optical, electrical and structural properties were investigated. The silane concentration appears to control orientation and grain size. Highly conductive μc-Si:H films were grown with high deposition rate at silane concentration of 3%. These films show an enhancement of the optical absorption in the near infrared region. In the visible region the absorption is lower than a-Si:H, however the transient PC signal, induced by 532 nm laser pulses (6 ns time duration), shows an high amplitude and a width comparable with the optical pulse one. μc-Si:H materials can be used for fast photodetectors of pulsed visible light.