Investigations of the ionizing radiation induced effects in ultra-thin strained-silicon layers on insulator using confocal microscopy measurements

This study describes investigations on the ionizing radiation effects induced in ultra-thin Silicon-On-Insulator (SOI) devices. Electrical tests exhibit various behaviors after irradiation which depends on the intrinsic mechanical stress of the thin silicon film. The electrical characteristics of strained Silicon-On-Insulator devices evidence a decrease of the subthreshold slope that may be related to a radiation induced degradation of the carrier mobility. This appears in addition to the deviation of the threshold voltage classically observed on irradiated Silicon-On-Insulator samples. The major issue discussed in this paper is whether a strain relaxation or the buildup of interface states at strained silicon/silica interfaces leads to the observed carrier mobility degradation. Radiation-induced mechanisms are then discussed with electrical measurements and optical spectra obtained by confocal microscopy measurements which have already demonstrated their potential to probe irradiated materials. (C) 2011 Elsevier B.V. All rights reserved.