2 MeV electron irradiation effects on the electrical characteristics of MOS capacitors with ALD Al2O3 dielectrics of different thickness

• 2 MeV electron irradiation on Si MOS capacitors with ALD Al2O3 of different thickness.
• Capacitance-voltage and current-voltage characteristics as a funtion of irradiation.
• Radiation-induced change of sign of effective charges for the thickest Al2O3 layers.
• Increase of leakage current with irradiation fluence for the thickest Al2O3 layers.
• The effects are significantly lower or even negligible for the thinnest Al2O3 films.

The effects of 2 MeV electron irradiation on the electrical characteristics of atomic layer deposited layers of Al2O3 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 Al2O3 films.