Radiation-induced defects in Si diodes were investigated after exposure to high doses of 60Co γ-irradiation using the thermally stimulated current method. It was found that, for high irradiation doses, a second-order defect could be detected. This defect was largely suppressed in O-enriched material while it was the main cause for the space charge sign inversion effect observed in standard float-zone material.

Second-Order Generation of Point Defects in Gamma-Irradiated Float-Zone Silicon, an Explanation for “Type Inversion”. I.Pintilie, E.Fretwurst, G.Lindström, J.Stahl: Applied Physics Letters, 2003, 82[13], 2169-71