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

摘要

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.