The effects of grain boundary scattering on electrical resistivity of Ag/NiSi silicide films formed on silicon substrate at 500 °C by RTA

Abstract

Abstract The temperature-dependent resistivity measurements of Ag/Ni-Si silicide films with 28–260 nm thicknesses are studied as a function of temperature and film thickness over the temperature range of 100–900 K. The most striking behavior is that the variation of the resistivity of the films with temperature exhibits an unusual behavior. The total resistivity of the Ag/Ni-Si silicide films in this work increases linearly with temperature up to a T m temperature, and thereafter decreases rapidly. Our analyses have shown that in the temperature range of 100 to T m °K, the parallel-resistor formula reduces to Matthiessen's rule and θ D (Debye temperature) have been found to be about 201–404 K for the films. The correlation of the Ag/Ni-Si silicide formation with its electrical and morphological properties is also established. We have also shown that for temperature range of 100– T m °K, linear variation of the resistivity of the silicide films with temperature has been caused by both grain-boundary scattering and electron-phonon scattering. That is why resistivity data could have been analyzed successfully in terms of the Mayadas–Shatzkes (M–S) model. Theoretical and experimental values of reflection coefficients have been calculated by analyzing resistivity data using the M–S model. According to our analysis, R increases with decreasing film thickness for a given temperature. For room temperature, theoretical and experimental reflection coefficients have been calculated to be R th = 0.264, R exp = 0.296 for the thinnest sample (28 nm). On the other hand, for the thick sample (260 nm), these reflection coefficients have been determined as R th = 0.027, R exp = 0.048.