CHARGE-CARRIER LIFETIME MODIFICATION IN SILICON BY HIGH-ENERGY H-IMPLANTATION( OR HE+ ION)

H+ or He+ was implanted at energies of 1, 2.5 and 4 MeV into n-type [1 00] 4-7.5 Omega cm CZ-Si with doses in the range from 3 x 10(10)/cm(2) to 1x10(12)/cm(2). A reduction in minority carrier lifetime was measu red by the microwave photoconductive decay (mu-PCD) method using a 904 nm laser pulse. It was shown that the modified lifetime can be direct ly measured by mu-PCD when the damaged region and the excess charge po cket generated by the laser pulse exactly overlap, This was the case f or 4 MeV H+ implantation. For shallower defects, the measured lifetime value is influenced by the diffusion process of excess minority carri ers. To extract the real lifetime in this case, a three layer model is presented.