Metallization of poly(ethylene terephthalate) in the wide range of substrate temperatures

In this work, we present structural and compositional analysis of silver layers on PET and relation between the stress level and process conditions. The silver thin films (1 μm thickness) were deposited on PET (25 μm thickness) by electron beam evaporation in vacuum at different substrate temperatures (20, 40, 80 and 120 °C). The size of the crystal grain was obtained from the peak width of X-ray diffraction using the two major models known and employed in bulk materials: the integral breadth and the Warren–Averbach methods. The classical sin2ψ method of X-ray diffraction was used to measure the residual stresses in fine grained polycrystalline materials. The influence of metal coverage on interface composition, structure, morphology, and particle size of Ag/PET films has been studied employing X-ray photoemission spectroscopy (XPS), atomic force microscopy (AFM) and X-ray diffraction (XRD).According to the AFM and XRD, the structural changes in the polymer occurring above the glass transition temperature of PET (Tg ≈ 80 °C) may contribute to the morphological and stress changes in the Ag/PET system.