Carbon-based materials, i.e., amorphous hydrogenated and nonhydrogenated forms of carbon, have attracted much attentions for application in microelectronic devices due to their importance in electrical, optical, and tribological properties. In this work, the hydrogenated amorphous carbon films were deposited by close field unbalanced magnetron (CFUBM) sputtering method with a graphite target in a mixed Ar (80%) and C2H2 (20%) plasma. We have observed a systematic variation for the properties of these films with the increase of DC bias voltage from 0 to -200 V. The investigation of the composition and structure was performed by Raman analysis, FT-IR (Fourier transform infrared) spectroscopy, and AFM (Atomic Force Microscopy). The electrical properties were observed by current-voltage (I-V) measurement and electrical resistivity. (c) 2004 Elsevier B.V. All rights reserved.