Structural, mechanical and electrical properties of sputter-coated copper thin films on polyethylene terephthalate

In this study, ion-beam-sputtering technique is used to prepare nanocomposite films, consisting of deposited copper nanoparticles (CuNPs) on polyethyleneterephthalate (PET). The successful formation of the flexible Cu/PET composite films is confirmed by X-ray diffraction (XRD). The surface morphology of Cu/PET is studied by atomic force microscopy (AFM). The results show that the surface roughness increased from 22.6 nm for PET to 45.3 nm after 40 min of deposited Cu/PET. The sheet resistance decreases from 5.16 x 10(4) Omega to 1.3 x 10(4) Omega and resistivity decreases from 2.3 x 10(-2) Omega .cm to 1.77 x 10(-2) Omega .cm, as the Cu deposition time increases from 20 min to 60 min. Moreover, Young's modulus increases from 2.82 GPa to 2.96 GPa and the adhesion force enhances from 14.7 nN to 29.90 nN after 40 min of Cu deposition. The DC electrical conductivity at 300 V is improved from 1.75 x 10(-8) S.cm(-1) to 3.57 x 10(-8) S.cm(-1) after 60 min of Cu deposition. The results show the deposited Cu on flexible PET platform clearly exhibits improvement over pristine PET in the mechanical and electrical properties which render it useful for a broad range of dielectric applications.