p- and n-type microcrystalline Si1−C fabricated by plasma CVD with 40.68-MHz excitation source

Abstract We have investigated p- and n-type microcrystalline Si1−xCx (μc-SiC) thin films fabricated by a plasma chemical vapor deposition method using an excitation frequency of 40.68 MHz in comparison with those fabricated with conventional 13.56-MHz excitation. The μc-SiC films were deposited employing a new carbon source of C2H6 gas on a glass substrate at a low substrate temperature. Differences in structural, optical and electrical properties of the μc-SiC films that occur with the increase in the excitation frequency are discussed. Regarding μc-SiC deposited with 40.68-MHz excitation and reduced total gas flow rate, the optical energy gaps and dark conductivities simultaneously increase due to an increase in the unintentionally introduced oxygen concentration rather than to an increase in the carbon content.