Surface analysis of the initial stages of Si film growth

Silicon films were deposited on gold-coated glass, copper-coated glass, bare polyethylene terephthalate (PET), and gold-coated PET substrates for times ranging from 10 s to 40 min at 130 °C for PET and 200 °C for the other substrates in order to study the chemistry of the initial stages of film growth. X-ray photoelectron spectroscopy (XPS) shows the formation of silicon oxide immediately upon commencement of the film growth. This oxide persists throughout the duration of the film growth. In PET films, the oxide is the dominant component of the Si 2p XPS peak, whereas it exists only as a minor, high-energy shoulder on the Si 2p peak for gold and copper-coated glass substrates and gold-coated PET substrates, indicating a less contaminated silicon film. X-ray diffraction (XRD) indicates that films grown on gold-coated glass for 40 min were polycrystalline with a (1 1 1) preferred orientation, and an average grain size of 95 ± 5 nm.