Hydrogen‐free diamond‐like carbon (DLC) films were deposited by the layer‐by‐layer technique using plasma enhanced chemical vapor deposition (PECVD), i.e., the alternative deposition of thin DLC layer and subsequent CF4plasma exposure on its surface. The hydrogen‐free DLC could be grown on the Si wafer by repeated deposition of the 5 nm DLC layer and subsequent 200 s CF4plasma exposure on its surface. On the other hand, the conventional DLC deposited by PECVD contains 25 at. % hydrogen inside. The CF4plasma exposure on the thin DLC layer appears to etch weak C–C bonds and break hydrogen bonds, resulting in a widening optical band gap and increasing conductivity activation energy. ©1996 American Institute of Physics.