Formation kinetics of CrSi2 films on Si substrates with and without interposed Pd2Si layer

Abstract

We have measured the kinetic rate of formation of CrSi₂ using 2.0‐MeV ⁴He⁺ backscattering spectrometry. CrSi₂ was formed on single‐crystal 〈100〉‐ and 〈111〉‐oriented Si and on Pd₂Si grown on 〈100〉 Si. For both Si‐Cr and Si‐Pd₂Si‐Cr samples the rate of growth of CrSi₂ is linear in time with an activation energy of 1.7±0.1 eV and a value of 0.7 Å/sec at 450 °C. For all annealing temperatures, the growth becomes nonlinear at long annealing times. The nonlinearity is attributed to a contaminant, probably oxygen. On Pd₂Si, CrSi₂ starts to form at about 400 °C, while on Si, CrSi₂ formation is observed at 450 °C and above. The difference in formation temperatures is due to contamination at the Si‐Cr interface, quite probably a thin oxide layer. The growth rate of CrSi₂ in the Si‐Pd₂Si‐Cr samples is independent of the thickness of Pd₂Si.