2 MeV electron irradiation effects on the electrical characteristics of MOS capacitors with ALD Al_2O_3 dielectrics of different thickness

摘要

The effects of 2 MeV electron irradiation on the electrical characteristics of atomic layer deposited layers of Al_2O_3 with different thickness are evaluated by using metal-oxide-semiconductor capacitors with a dielectric physical thickness ranging from 2.8 nm to 11.6 nm. The capacitance-voltage and current-voltage characteristics of the capacitors are analysed as a function of electron irradiation. A progressive radiation-induced positive charge trapping and increase of the leakage current with electron fluence is observed for the thickest layers subjected to electron irradiation. However, the effects are significantly lower or even negligible for the thinnest Al_2O_3 films.