Calculation of the electron-transfer parameters of thin polycrystalline films of metals

Abstract

Electron transfer parametrs (scattering coefficient R, crystal-boundary transmission coefficient r, film-surface reflection coefficient) are calculated at temperatues t_msm=120, 293, and 573 K using Sc and Re films as an example. The conditions L ≳ d and L < d are satisfied, respectively, for these films (L is the mean diameter of the crystals and d is the thickness of the specimens). The films were obtained in a vacuum of 10⁻⁶-5·10⁻⁷ Pa. In the thickness ranges d≅200–500 Å (Re) and 300–800 Å (Sc), the films had a mean crystallite size of 250 and 600 Å, respectively. Experimental data on the dimensional effect of the temperature coefficient of resistance β was analyzed within the framework of the Mayadas-Shatzkes (MS) theory, the model of isotropic carrier scattering, and the three-dimensional Tellier-Tosser-Pichard (TTP) model. It was concluded that the electrophysical properties of Sc films are satisfactorily described by the TTP model, while the MS theory yields exaggerated values of the coefficients r and p. In the case of films of Re, use was made of the isotropic scattering model and an approximation of the three-dimensional model for polycrystalline films. It was found that the coefficients r and R are independent of temperature.