FTIR characteristics of hydrogenated amorphous carbon films prepared by ECR-PECVD

Hydrogenated amorphous carbon (a-C:H) films were prepared by using electron cyclotron resonance plasma-enhanced chemical-vapor deposition (ECR-PECVD) and various values of the ECR plasma source power, the methane gas flow rat e, the deposition time, and the substrate bias voltage. The characteristics of the atomic bonding structure between carbon and hydrogen in the films w ere analyzed using Fourier transform infrared (FTIR) spectroscopy, From an analysis of the IR absorption peaks which appeared in the range of 2800 sim ilar to 3000 cm(-1), it was found that the bonding structure between C and H in a-C:H films consisted mostly of sp(3) with Some sp(2), bonding. The fo rm of the carbon-to-hydrogen bond in the films changed from CH3 to CH2 or C H as the deposition time increased. The effect of substrate bias voltage du ring fabrication of a-C:H films indicated that the number of carbon-tu-hydr ogen bonds in the film decreased with increasing bias voltage because of en ergetic bombardment of the surface by ions.