Diamond-like carbon (DLC) films were deposited on polyethylene terephthalate (PET) substrates with the rf plasma chemical vapor deposition method using C2H2 gas and were investigated on the chemical bonding characteristics and microstructures, comparing with those on Si substrates. At the initial stage of deposition (similar to10 s), the DLC films deposited on PET substrates contained more sp(2) bonds and the growth rate was higher. Then, the number of sp(3) bonds increased and became unchanged after 10 s of deposition. Similar results were observed for DLC films on Si substrates. When the input power of rf plasma equipment was higher, the C 1s x-ray photoelectron spectra from DLC films shifted to higher binding energy, but this shift was not observed for the films on Si substrates. Transmission electron microscope observation showed that the films were uniformly deposited on PET substrates and had amorphous structure without graphitic structure even in the restricted area. (C) 2003 American Vacuum Society.