A comparison of 48MeV Li3+ ion, 100MeV F8+ ion and Co-60 gamma irradiation effect on N-channel MOSFETs

Abstract: N-channel MOSFETs were irradiated by 48MeV Li3+ ions, 100MeV F8+ ions and Co-60 gamma radiation with doses ranging from 100krad to 100Mrad. The threshold voltage (V TH), voltage shift due to interface trapped charge (ΔV Nit), voltage shift due to oxide trapped charge (ΔV Not), density of interface trapped charge (ΔN it), density of oxide trapped charge (ΔN ot), transconductance (g m), mobility (μ) of electrons in the channel and drain saturation current (I D Sat) were studied as a function of dose. Considerable increase in ΔN it and ΔN ot, and decrease in V TH, g m and I D Sat were observed in all the irradiated devices. We correlated the degradation of μ with the ΔN it and the effect of ΔN ot is found to be negligible for degrading the μ. The maximum degradation was observed for the devices irradiated with Co-60 gamma radiation when compared with those irradiated with ions, since gamma radiation can generate more trapped charge in field oxide when compared to the high energy ions. [Copyright &y& Elsevier]