The dependence of filtered vacuum arc deposited ZnO-SnO2 thin films characteristics on substrate temperature

Cetinorgu E., Goldsmith S., Barkay Z., Boxman R. L.

JOURNAL OF PHYSICS D-APPLIED PHYSICS, vol.39, no.24, pp.5245-5251, 2006 (SCI-Expanded) identifier identifier


ZnO-SnO2 thin films were deposited by filtered vacuum arc deposition system and characterized using x-ray diffraction (XRD), energy dispersive spectroscopy, atomic force microscopy (AFM), spectrophotometer and ex situ variable angle spectroscopic ellipsometry. According to the XRD analysis the films were amorphous, independent of the deposition conditions. The root-mean-squares (RMS) of surface roughness and the average grain size obtained from the AFM images were 0.2-0.8 nm and 15-20 nm, respectively. Averaged optical transmission was 85%, and the refractive index and extinction coefficient of the films were in the range 2.05-2.28 and 0.001-0.044 at 500 nm wavelength, respectively. The range of the optical band gap of the films was 3.43-3.70 eV, depending on deposition conditions. The lowest resistivity was of the order of 10(-2) ohm cm for films deposited on 400 degrees C heated substrates, while films deposited on substrates at room temperature were non-conducting, and films on 200 degrees C heated substrates were weakly conducting(similar to 10(1-2) ohm cm). The resistivity of films decreased with increasing pressure for 200 and 400. C heated substrates relative to RT deposited films. The effect of deposition conditions on the optical constants was analysed statistically by single and two sided variance analysis, using the analysis code 'Analysis Of Variance' to determine the significance of the differences between sets.