Analysis of 80-MeV Carbon and 80-MeV Nitrogen Ion Irradiation Effects on N-Channel MOSFETs

N-channel depletion MOSFETs were irradiated with 80 MeV Carbon (C
⁶⁺
) and 80 MeV Nitrogen (N
⁶⁺
) ions in the dose range from 100 krad (Si) to 30 Mrad (Si). The electrical characteristics of MOSFET such as threshold voltage (V
_th
), density of interface trapped charges (AN
_it
), density of oxide trapped charges (AN
_ot
), transconductance (g
_m
), mobility (μ), leakage current (I
_L
) and drain saturation current (IDSat) were studied as a function of dose. A considerable increase in AN
_it
and AN
_ot
and decrease in V
_th
, g
_m
, μ, and ID Sat was observed after irradiation. The μ was correlated with AN
_it
and it is found that the contribution of AN
_ot
in degrading the mobility of charge carriers is negligible.The ion irradiated results were compared with Co-60 gamma irradiated results and found that the degradation is more for Co-60 gamma irradiated devices at lower doses, whereas at higher doses, the degradation is more for heavy ion irradiated devices.