Influence of film qualities on noise characteristics of a-Si1−xCx:H thin films deposited by PECVD

This paper describes the influence of film qualities of boron doped hydrogenated amorphous silicon carbide (a-Si1−xCx:H) on the 1f noise in use as semiconductor thermistors. The dependencies of rf-power, CH4SiH4 and B2H6SiH4 gas flow ratio are confirmed experimentally. As the rf-power increased, 1f noise dramatically decreased. Enhancing decomposition of CH4 gas results in reducing the amount of SiCH3 and CHn bonds which were found to be the key factors to reduce noise. As the B2H6SiH4 gas flow ratio increased, carrier density of the film also increased and the increasing rate of 1f noise at low temperature was dramatically reduced. By optimizing deposition parameters, we have successfully fabricated superior thermistors with low noise and high sensitivity characteristics.