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Hydrogenated amorphous carbon (a-C:H) films were prepared by reactive very high frequency magnetron sputtering at hydrogen partial pressure of 0 Pa to 1 Pa and substrate biases 0V, 50V and 100V. Influence of substrate bias on hydrogen content, bonding hydrogen configuration and optical energy gap in the a-C:H films were investigated by FT-IR spectroscopy and UV-VIS spectroscopy. As applying substrate bias, the range of hydrogen partial pressure in which the films were able to be formed become narrow. The trend of the dependence of hydrogen content in the a-C:H films prepared with. substrate bias is similar to that without substrate bias. However, the position of partial pressure at the maximum of the hydrogen content shifts toward low pressure with substrate bias. We considered that these results could be due to enhancement of etching process on growing surface by increasing substrate bias. It is also found that optical energy gaps of the films were dependent on strongly the hydrogen content. This result would suggest that the compensation of dangling bond in the films by hydrogen was concerned in optical energy gap.

Hydrogenated amorphous carbon (a-C:H) films were prepared by reactive very high frequency magnetron sputtering at hydrogen partial pressure of 0 Pa to 1 Pa and substrate biases 0V, 50V and 100V. Influence of substrate bias on hydrogen content, bonding hydrogen configuration and optical energy gap in the a-C:H films were investigated by FT-IR spectroscopy and UV-VIS spectroscopy. As applying substrate bias, the range of hydrogen partial pressure in which the films were able to be formed become narrow. The trend of the dependence of hydrogen content in the a-C:H films prepared with. substrate bias is similar to that without substrate bias. However, the position of partial pressure at the maximum of the hydrogen content shifts toward low pressure with substrate bias. We considered that these results could be due to enhancement of etching process on growing surface by increasing substrate bias. It is also found that optical energy gaps of the films were dependent on strongly the hydrogen content. This result would suggest that the compensation of dangling bond in the films by hydrogen was concerned in optical energy gap.