During the preparation of the substrates, involving ion implantation (> 1014 O* cm−2) and extended high temperature annealing (∼ 1350°C), many defects are unintentionally introduced, which can act as trapping and recombination centres. In this paper the carrier lifetime distributions and recombination kinetics determined by Photoconductive Frequency Resolved Spectroscopy (PCFRS) are reported. Comparative measurements of the lifetime distributions in bulk silicon, annealed bulk silicon and device quality SIMOX have been made. In annealed silicon and SIMOX higher order recombination kinetics are observed whilst, as expected, the kinetics are first order in unannealed bulk silicon.
Results of PCFRS measurements made as a function of temperature in the range 350 K to 150 K reveal a strong dependence of the lifetime distribution on temperature, confirming the dominance of carrier trapping. Trap parameters have been obtained from Arrhenius plots of the lifetime distributions.