Structure, microhardness and deformation were investigated, following neutron irradiation, by using optical microscopy and atomic force microscopy. Electron beam-induced current scanning electron microscopy was used for the direct investigation of the effect of neutron irradiation upon a p-n junction space-charge region. The irradiation resulted in a deterioration of the electronic performance. The results showed that, for neutron fluences of 9.9 x 1010 to 3.12 x 1015/cm2, the damage was accumulative. Sudden changes in microstructure, and electrical and mechanical properties, appeared at almost the same fluence (1014/cm2). Microscopic studies showed that, with increasing fluence, various types of defects (dislocation loops, dislocation tangles) appeared. These dislocations were displaced to specific regions; due to vacancies and interstitials which increased their accumulation. Strongly damaged regions were seen microscopically as black islands and the damaged regions were seen as white islands. Atomic force microscopy showed that the white regions contained a smaller number of dislocation loops and a large number of single point defects.

Atomic Force Microscopic Investigation of Dislocation Structures and Deformation Characteristics in Neutron-Irradiated Silicon Detectors. G.Golan, E.Rabinovich, A.Inberg, M.Oksman, P.G.Rancoita, M.Rattaggi, K.Gartsman, A.Seidman, N.Croitoru: Microelectronics Journal, 2000, 31[11-12], 937-44