An ab initio plane-wave ultrasoft pseudopotential method based on the generalized gradient approximations was utilized to investigate the electronic structure, atomic geometry, formation energy to provide a better understanding of properties of Ni disilicide. The vacancy and interstitial formation energies depended largely upon the atomic chemical potentials. The formation energies of vacancies VSi and VNi were in the range of 0.04 to 0.56eV and 1.25 to 2.3eV, respectively and the formation energies of Si and Ni interstitials were 3.89 to 4.42eV and 0.67 to 1.71eV, respectively. The smaller Ni interstitial formation energy was in agreement with the experimental result that Ni interstitial atom was dominant diffusion species in NiSi2.

Ab initio Calculation of Vacancies and Interstitials in NiSi2. T.Wang, Y.B.Dai, S.K.Ouyang, J.S.Wu, H.S.Shen: Chinese Physics Letters, 2004, 21[11], 2163-6