Influence of {\alpha}-particles irradiation on the performance and defect levels structure of Al/SiO2/p-type Si surface barrier detector

TL;DR

This study investigates how alpha-particle irradiation affects the performance and defect structure of Al/SiO2/p-type Si surface barrier detectors, revealing increased defect levels and changes in electrical characteristics after irradiation.

Contribution

It provides detailed analysis of defect level formation and electrical parameter deterioration in Si detectors caused by alpha-particle irradiation, using CV and DLTS techniques.

Findings

Increased FWHM of alpha peaks from 70 keV to 100 keV after irradiation.

Detection of at least 6×10^12 cm^-3 radiation-induced acceptors.

Identification of V2O defects linked to space charge sign inversion.

Abstract

Deterioration of the operation parameters of Al/SiO2/p-type Si surface barrier detector upon irradiation with alpha-particles at room temperature was investigated. As a result of 40-days irradiation with a total fluence of 8*10^9 {\alpha}-particles, an increase of {\alpha}-peak FWHM from 70 keV to 100 keV was observed and explained by increase of the detector reverse current due to formation of a high concentration of near mid-gap defect levels. Performed CV measurements revealed the appearance of at least 6*10^12 cm-3 radiation-induced acceptors at the depths where according to the TRIM simulations the highest concentration of vacancy-interstitial pairs was created by the incoming {\alpha}-particles. The studies carried out by current-DLTS technique allowed to associate the observed increase of the acceptor concentration with the near mid-gap acceptor level at EV+0.56 eV. This level can be apparently associated with V2O defects recognized previously to be responsible for the space charge sign inversion in the irradiated n-type Si detectors.