Depth profiles of the nickel donor center in p-type silicon diffused with dilute nickel measured by deep-level transient spectroscopy

Abstract

The depth profiles of the nickel donor center located at Ev + 0.17 eV (Ev: the top energy of the valence band) in p-type silicon diffused with dilute nickel at 525–900 °C and slowly cooled to room temperature were measured. Owing to the domination of the fast outdiffusion of nickel, the nickel center concentration at the sample surface was highest for the sample diffused at 525 °C, which abruptly decreased with increasing diffusion temperature. The concentrations of the center in the samples diffused at intermediate temperatures sharply increased with increasing depth and converged to an asymptotic value in the deep region. The concentration fractions of the center of the dissolved nickel in the deep region were 4 to 12% for the samples diffused below 900 °C, which were unexpectedly high compared with previous data. A possible formation mechanism of the center through a nitrogen-related defect was discussed.