Activation energy for the C49-to-C54 phase transition of polycrystalline TiSi2 films with arsenic impurities

Abstract
The C49‐to‐C54 transition in TiSi2 was investigated using samples having submicron line width film, by an x‐ray diffraction technique. Arrhenius plots of the transition rate show that the C49‐to‐C54 transition of polycrystalline TiSi2 films with arsenic impurities have an activation energy barrier strongly dependent on the arsenic concentration. The energy increases as a function of arsenic impurity concentration, from 3.5 eV for TiSi2 formed on Si substrate ion implanted with the dose of 2×1015 cm−2, to 7.8 eV with the dose of 5×1015 cm−2. The annealing time dependence of the x‐ray intensity on (004) orientation indicates that TiSi2 formed on Si substrate with the arsenic dose of 2×1015 cm−2 shows a diffusion‐limited process and that with the dose of 5×1015 cm−2 shows an interface‐limited process. The arsenic precipitates act to pin the C49 phase in the C49‐to‐C54 transition.