H+ or He+ was implanted at energies of 1, 2.5 and 4 MeV into n-type 〈100〉 4–7.5 Ω cm CZ-Si with doses in the range from 3 × 1010/cm2 to 1 × 1012/cm2. A reduction in minority carrier lifetime was measured by the microwave photoconductive decay (μ-PCD) method using a 904 nm laser pulse. It was shown that the modified lifetime can be directly measured by μ-PCD when the damaged region and the excess charge pocket generated by the laser pulse exactly overlap. This was the case for 4 MeV H+ implantation. For shallower defects, the measured lifetime value is influenced by the diffusion process of excess minority carriers. To extract the real lifetime in this case, a three layer model is presented.
