Shallow level analysis in irradiated silicon

Silicon p/sup +//n/n/sup +/ junctions with nominal starting resistivity of 4-6 k/spl Omega/cm have been irradiated with a 1 MeV neutron-equivalent fluence up to 4/spl middot/10/sup 14/ cm/sup -2/. In order to investigate the changes in the shallow level concentrations induced by irradiation, low temperature Thermally Stimulated Current measurements have been performed. For fluences over 10/sup 13/ cm/sup -2/ a phosphorous removal is observed, probably due to the formation of the vacancy-phosphorous complex.