Abstract
Hydrogen bonding configurations and hydrogen content of a-C:H films deposited by H-assisted plasma CVD were investigated by Fourier transform infrared spectroscopy. Plasma parameters related to deposition rate were derived using optical emission spectroscopy. The a-C:H films contain a large number of sp3 configurations (93%) and a few sp2 configurations (7%). Most of the hydrogen is bonded in methyl groups which shows the structure of deposited a-C:H films is polymer-like carbon. The mass density has nearly linear decreases with increasing the hydrogen atom density, indicating that control of hydrogen content is crucial to obtain a-C:H films of high mass density. A slight increase in radical generation rate and significant increases in etching rate by hydrogen atoms lead to decrease the deposition rate when the discharge voltage increases from 170 V to 180 V.
