Frequency dependence of conductivity in intrinsic amorphous silicon carbide film, assessed through admittance measurement of metal insulator semiconductor structure

A slightly carbon rich hydrogenated amorphous silicon carbide (a-SiCx:H) film was deposited by 13.56 MHz plasma enhanced chemical vapor deposition technique on p-type silicon (p-Si) wafer. Admittance analyses of the metal-insulator-semiconductor device (Al/a-SiCx:H/p-Si) from strong accumulation to strong inversion gate bias were achieved within a widespread frequency range (101–106 Hz). An adequate equivalent circuit for each bias regime was proposed. The dependence of the ac conductivity both under strong accumulation and inversion on the frequency power-law was interpreted as due to the carrier exchange mechanism by hopping.