Properties of Silicon Doped with Nickel

Abstract

Measurements of the temperature dependence of the resistivity and Hall coefficient of nickel-doped silicon indicate that nickel acts as an acceptor impurity in silicon, introducing two acceptor levels, namely, 0.35±0.03 eV from the conduction band and 0.23±0.03 eV from the valence band. Precipitation of nickel from supersaturated solution in silicon has also been studied. The results can be expressed nearly as an exponential decay with time of the unprecipitated fraction of nickel. Precipitate particles of nickel in heat treated samples are observed by infrared microscopic inspection, but typical cylindrical precipitates are not observed. Therefore, according to Ham's theory the particles are most likely of finite dimension at the start of the precipitationmeasurements. This is probably attributable to the fairly long cooling time, about 40 seconds, after nickel diffusion. Thus, it is expected that nickel atoms have fairly precipitated in the course of the cooling. The nuclei for precipitation of nickel may be considered to be vacancies generated at dislocations.