Temperature and thickness dependence of the grain boundary scattering in the Ni–Si silicide films formed on silicon substrate at 500 °C by RTA

Highlights: ► It is a systematic study of various thicknesses (18–290 nm) of Ni–Si silicide films. ► The temperature-dependent resistivity measurements of the films are studied. ► Resistivity variation of the films with temperature exhibits an unusual behavior. ► Parallel-resistor formula is reduced to Matthiessen's rule in this study. ► Reflection coefficients have been found in a wide temperature and thickness range. - Abstract: The temperature-dependent resistivity measurements of Ni–Si silicide films with 18–290 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 Ni–Si silicide films in this work increases linearly with temperature up to a Tm temperature, thereafter decreases rapidly and finally reaches zero. Our analyses have shown that in the temperature range of 100 to Tm (K), parallel-resistor formula reduces to Matthiessen's rule and θD Debye temperature becomes independent of the temperature for the given thickness range, whereas at high temperatures (above Tm) it increases slightly with thickness. θD Debye temperature have been found to be about 400–430 K for the films. We have also shown that for temperature range of 100 to Tm (K), linear variation of the resistivity of the silicide films with temperature has been caused from both grain-boundary scattering and electron–phonon scattering. That is why, resistivity data could have been analyzed in terms of the Mayadas–Schatzkes (M–S) model successfully. Theoretical and experimental values of reflection coefficients have been calculated by analyzing resistivity data using M–S model. According to our analysis, R increases with decreasing film thickness for a given temperature, while it is almost constant for the thickness range of 200–67 nm and 47–18 nm, over which silicide films show almost the same phases, also confirmed by our XRD, SEM and RBS measurements.