A detailed microscopic analysis of deep levels in heavily irradiated-medium resistivity silicon detectors

In this work we show a detailed deep levels analysis (an energy resolution of 50 meV was reached) of a set of medium resistivity silicon samples, irradiated up to a fluence of 2.5·10¹⁵ n/cm ². In order to discriminate the large number of deep levels which appear to overlap their contributions in TSC and I-DLTS spectra, we adopted an innovative numerical procedure of data analysis which determines a set of deep levels that can account for both TSC and I-DLTS spectra. We finally obtained a consistent and detailed description of deep level population, clearly showing its evolution with fluence. Some results seem to suggest the possibility of quasi-continuous distributions of localized states inside the gap