Neutron induced defects in silicon detectors characterized by DLTS and TSC methods

Abstract

Neutron induced defects in silicon detectors fabricated from n-type float zone material of different resistivity (100–6000Ω cm) have been studied using the C-DLTS (Capacitance-Deep Level Transient Spectroscopy) and TSC (Thermally Stimulated Current) method. While the application of the C-DLTS technique for high resistivity material is limited to neutron fluences below about 10 11 cm −2 the TSC method remains a powerful tool for the defect characterization even at high fluences. Up to 5 defect levels were observed in some of the unirradiated samples. These partly are due to thermal treatments during the fabrication process. After neutron irradiation defect levels at E c − 0.17, −0.23 and −0.42 eV and at E v + 0.36 eV were found. A detailed analysis of the predominant peak at about −0.42 eV has shown that it is a superposition of two levels at −0.39 and −0.42 eV. For these defect levels introduction rates, annealing effects and a comparison between the DLTS and TSC technique are presented. Possible correlations of these results with macroscopic detector properties are discussed.