Study of carrier recombination and trapping processes in γ-ray- and proton-irradiated silicon

Carrier lifetime variations dependent on proton irradiation at fluences in the range from 5×1012 to 1015 cm−2 and γ-ray doses ranging from 50 to 400 Mrad were investigated in high-resistivity oxygenated silicon wafers and pad detectors. Fast recombination and slow trapping constituents within recombination transients have been distinguished by combining analyses of excess carrier decays dependent on excitation intensity and temperature, measured using the technique of microwave absorption by free carriers. Difference in defect formation rate and type of defects in the ranges of moderate and highest proton irradiation fluences as well as between γ-ray- and proton-irradiated material have been revealed from the inverse lifetime dependence on irradiation fluence and on temperature. The activation factors of the capture centers have been evaluated from carrier lifetime variations in the range of low and elevated temperatures.