Cu/C:H composite films were prepared oil poly ethylene terephthalate (PET) substrate at room temperature by the electron cyclotron resonance-metal organic chemical vapor deposition (ECR-MOCVD) coupled with a negative direct current (DC) bias system. The negative DC bias voltage applied around the substrate strongly affected the crystallographic structure and composition as well as the surface toughness of the copper films. The surface resistivity of films decrease sharply as the bias voltage increase Lip to about 5 mu Omega-cm below which the resistivity remains almost constant in the range of - 900 to - 1700 V Thus, the bias voltage appeared to be a critical deposition parameter for preparing copper films with low resistivity. With interfacial studies Of CU-PET, copper atoms are embedded into the polymer substrate during the growth process. Therefore, Cu/C:H composite films oil PET with good interfacial properties Could be prepared by ECR-MOCVD coupled with a (-)DC bias system. (c) 2005 Elsevier B.V. All rights reserved.