PICTS analysis of extended defects in heavily irradiated silicon

Abstract

We report the results of an experimental study on radiation-induced defects in silicon p + n diodes irradiated with 1-MeV neutrons up to a fluence of 2.3 10 15 cm 2 . Heavily irradiated silicon diodes have been studied by means of Photo Induced Current Transient Spectroscopy (PICTS) technique using a variable filling time. For every filling time, a dominant broad and structured peak has been found in the temperature range 200-300 K. Such a broad peak cannot be accounted for by considering isolated point defects, being consistent with a quasi-continuous distribution of deep levels inside the bandgap. In addition, it is observed that the spectral lineshape tends to broaden as the filling time is increased. The details of the lineshape modifications depend strongly on the irradiation fluence of the sample, in such a way that they cannot be explained only in terms of emissions from noninteracting electron states. Thus we suggest that the investigated broad peak should, at least in part, be generated by emission from extended defects, also known as clusters.

Radiation Detection Properties of 4H-SiC Schottky Diodes Irradiated Up to$10^16$n/cm$^2$by 1 MeV Neutrons

“…It is well known that the degradation of the detectors with irradiation is caused by lattice defects, like creation of vacancies (point-like defects) or damage regions (cluster), independently from the material used for their realization, and, again, that a crucial aspect for the understanding of the defect kinetics at a microscopic level is the correct identification of the crystal defects in terms of their electrical activity. The understanding of the defect kinetics, in fact, would inform how to modify deliberately the material in order to reduce the degradation of the electrical properties of the detectors [16]- [18].…”