Energy Levels in Cobalt Compensated Silicon

Abstract

Measurements of the temperature dependence of resistivity and Hall coefficient in cobalt‐doped silicon show a donor level 0.40 eV from the valence band and an acceptor level 0.53 eV from the conduction band. These levels appear to be due to different charge states of the same center. Absorption and photoconductivity measurements support these determinations. Closed tube diffusions of silicon wafers on which cobalt has been evaporated result in maximum concentrations of electrically active cobalt of about 3×10¹⁴ cm⁻³.