Effect of deposition voltage on the microstructure of electrochemically deposited hydrogenated amorphous carbon films Original Research Article

Hydrogenated amorphous carbon (a-C:H) films were deposited on Si substrates by electrolysis in a methanol solution at ambient pressure and a low temperature (50 °C), using various deposition voltages. The influence of deposition voltage on the microstructure of the resulting films was analyzed by visible Raman spectroscopy at 514.5 nm and X-ray photoelectron spectroscopy (XPS). The contents of sp3 bonded carbon in the various films were obtained by the curve fitting technique to the C1s peak in the XPS spectra. The hardness and Young’s modulus of the a-C:H films were determined using a nanoindenter. The Raman characteristics suggest an increase of the ratio of sp3/sp2 bonded carbon with increasing deposition voltage. The percentage of sp3-bonded carbon is determined as 33–55% obtained from XPS. Corresponding to the increase of sp3/sp2, the hardness and Young’s modulus of the films both increase as the deposition voltage increases from 800 V to 1600 V.