Issues related to nuclear radiation effects on semiconductor devices

The nuclear radiation damage due to displacement and ionisation effects has been observed on semiconductor diodes and transistors. The devices were irradiated with gamma rays of integrated dose value of 100, 300 and 500 krads with a dose rate of 100 krads/hour. A decrease in the breakdown voltage capacity and increase in leakage current were observed for the rectifier diodes while the common emitter current gain of power transistors reduced to a low value and was found to be highly sensitive to the low dose rate values. Controlled annealing shows improvement in the post-radiation integrity of the lattice through recombination. Utilising the experimental database, the mathematical modelling of nuclear effects can predict life of the devices. Radiation hard power electronic system design approach is discussed.