Thermal emission rates and activation energies of electrons and holes at cobalt centers in silicon

The thermal ionization rates of electrons and holes at cobalt centers in silicon have been measured using the dark-capacitance and dark-current transient techniques. Using only n+–p diodes, the cobalt charge states, the thermal emission rates including their field dependences are determined. The thermal emission rate data fitted to et = A exp (−ΔE/kT) gives: (i) ΔE = ET − EV = (377 ± 1) meV and A = (4.43 ± 0.33) × 1013 s−1 for the donor level, (ii) ΔE = EC − ET = (569 ± 3) meV and A = (2.59 ± 0.38) × 1012 s−1 for the acceptor level.