Elevated temperature annealing of the neutron induced leakage current and corresponding defect levels in low and high resistivity silicon detectors

The leakage current (I/sub L/) annealing at elevated temperatures and the corresponding changes of the DLTS spectra of defects for fast neutron irradiated silicon detectors, fabricated on high (4-6 k/spl Omega/-cm), moderate (0.5-1.0 k/spl Omega/-cm), and low (<100 /spl Omega/-cm) resistivity silicon material, have been investigated. For all the resistivities, three annealing stages have been observed: (1) the transformation of carbon related defects at 72/spl deg/C; (2) slight decrease of the peak E/sub c/-0.4 eV at 150/spl deg/C, and (3) significant decrease of the peak E/sub c/-0.4 eV at 350/spl deg/C. The leakage current has been found to decrease monotonously in the temperature range of 20-150/spl deg/C. A sharp decrease of I/sub L/ was observed at 350/spl deg/C due to the annealing of the V-V center for heavily irradiated detectors, whereas I/sub L/ showed a slight saturation tendency for detectors irradiated to low neutron fluence. The V-V center has been found to be dominant in the formation of the E/sub c/-0.4 eV peak and in the annealing of the leakage current. For low resistivity detectors, an anneal at 72/spl deg/C was needed to stimulate the decrease of the effective impurity concentration (N/sub eff/) of the detectors irradiated by high neutron fluence (1-2)/spl times/10/sup 14/ n/cm/sup 2/. In addition, low resistivity detectors have been found to be tolerant in terms of N/sub eff/ stability to the 350/spl deg/C anneal, favorable to the recovery of I/sub L/ after irradiation with high neutron fluence.<>