Diffusion and electrical properties of nickel in silicon

Diffusion and electrical properties of nickel in silicon are extensively st udied. The deep level transient spectroscopy (DLTS) and Hall effect measure ments for nickel-doped silicon show that substitutional nickel exhibits an amphoteric nature in silicon, that is, substitutional nickel atoms introduc e one acceptor level at E-c - 0.47 eV in n-type silicon and one donor level at E-v + 0.18 eV in p-type silicon. The amphoteric nature has been confirm ed through isothermal capacitance transient spectroscopy measurements as th e neutral capture for majority carriers at the nickel levels. Interstitial nickel atoms in dislocation-free silicon appear to precipitate in the cryst al bulk during heat treatment at high temperature as well as during quenchi ng. Nickel precipitates are found to play an important role for the site ex change of nickel atoms between interstitial and substitutional sites, as si nks and sources (SS) of vacancies. In-diffusion and annealing processes of nickel in silicon are discussed on the basis of the model in which the nick el precipitates act as SS of vacancies.