Changes of chemical structure of hydrogenated amorphous silicon carbide films with the application of radio-frequency bias voltages during chemical vapor deposition

• a-SiCx:H films were fabricated by using the dissociation of Si(CH3)4 with the microwave plasma flow of Ar.
• Mechanically-hardness was obtained by applying the RF bias voltages to the substrate.
• Various parameters on the chemical structure of films were obtained as the function of the applied RF-bias voltage.
• O atoms are detected with significant fraction in the surface region, and they penetrate into the bulk region of films.

Hydrogenated amorphous silicon carbide films were fabricated using the decomposition of Si(CH3)4 with the microwave discharge flow of Ar. The changes of the chemical structure and the mechanical hardness of films were investigated upon the application of the radio-frequency bias voltages (− VRF) to the substrate. The analysis was based on a combination of Rutherford backscattering and elastic-recoil detection analysis, the X-ray photoelectron spectroscopy, the glow discharge optical emission spectroscopy, the nano-indentation measurements, and Fourier-transformed infrared spectroscopy. The fraction of the C–Si bonding state has a positive dependence on − VRF, whereas that of the C–C bonds in the sp3 hybridized state is negligible. In addition, hydrogen terminations were removed effectively under the low − VRF conditions of 0–20 V. The films show the penetration of O atoms from the atmospheric origin into the bulk region. The mechanical hardness of the present films is the result of the balance among these factors.

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