Low-frequency noise and radiation response of metal-oxide-semiconductor transistors with Al2O3/SiOxNy/Si(100) gate stacks

Low-frequency noise and irradiation response are studied for n-channel metal-oxide-semiconductor field-effect transistors with Al2O3/SiOxNy/Si(100) gate stacks. Radiation-induced threshold-voltage shifts and low-frequency noise increase with dose and decrease with postirradiation annealing. The border trap density in the gate dielectric inferred from the noise measurements is significantly higher than that typically observed in thermal SiO2. Similarly, the effective radiation-induced-hole trapping efficiency in Al2O3 gate dielectrics is significantly higher than for SiO2 gate dielectrics of comparable thickness. The low-frequency noise in these high-κ devices can be described well by a number fluctuation model.