Study of bulk damage in high resistivity silicon detectors irradiated by high dose of /sup 60/Co /spl gamma/-radiation

Displacement damage (or bulk damage) induced by high dose (>200 Mrad) /spl gamma/-radiation in high resistivity (6-10 k/spl Omega/-cm) silicon detectors has been studied. It has been found that detector bulk leakage current increases with /spl gamma/ dose at a rate of 3.3/spl times/10/sup -7/ A/cm/sup 3//Mrad. This damage rate of bulk leakage current originates from the introduction of generation centers and at a dose of 210 Mrad of /spl gamma/-radiation is comparable to that induced by 1/spl times/10/sup 12/ n/cm/sup 2/ of neutron radiation. Nearly 100% donor removal and/or compensation was found in detectors irradiated to 215 Mrad. Space charge sign inversion (SCSI) was observed in detectors irradiated to /spl ges/215 Mrad using the transient current technique (TCT). As many as six deep levels have been observed by current deep level transient spectroscopy (I-DLTS). There was insignificant annealing and no reverse annealing even after elevated temperature treatment for detectors irradiated to 215 Mrad. A small amount of reverse annealing (10 to 15%) has been observed during the room temperature storage period of about 11 months for detectors irradiated to 500 Mrad.