Abstract
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Effect of gamma and proton irradiation on threshold voltage shift ��V(T) for n-channel MOSFET has been studied. For MOSFET with zero gate bias during gamma irradiation the shift ��V(T) is linear with dose D(��) (up to doses of 10 Gy) and the sensitivity ��V(T)/D(��) is approximately 120 mV �� Gy-1. The sensitivity of MOSFETs with positive gate bias V(g) during irradiation varies as V(g)(2/3) and no saturation is observed up to breakdown voltage. n-MOSFETs with bias of 100 V have the sensitivity of approximately 5 V �� Gy-1. When n-MOSFETs are irradiated with 50 MeV protons the shift ��V(T) varies as D(p)0.67 (for proton doses D(p) ranged from 0.2 to 900 Gy). The positive charge storage in oxide is shown to contribute mainly to the radiation sensitivity of n-MOSFETs investigated.