Fast neutron irradiation effects of silicon MOS-controlled thyristor

Abstract

The effects of fast neutron radiation up to flux of 1014 cm−2 (1 MeV equivalent flux) upon the turn-on and forward static characteristics of MOS-Controlled Thyristor (MCT) are described in this work, based on physics-based 1-dimension analytical calculation and 2-dimension Silvaco simulation. It is reported for the first time that dependency of on-state specific resistance (Ron) upon neutron flux varies with the level of flux. At low flux range (∼1011 cm−2), MCT's on-state behavior is familiar with PIN diode and R on just increases slightly. At middle flux range (∼1011-1013 cm−2), Ron increases quadratically with the increasing of neutron flux and its value is still on the order of mΩ·cm2. Once neutron flux exceeds its critical value (∼1013 cm−2), MCT structure could not be turned on by MOS-gated structure and Ron increases drastically to the value on the order of Ω·cm2. A new on-state behavioural model is also advised for this circumstances, which is PN junction in series with vertical double drift MOS (VDMOS). Furthermore, it shows that the forward reverse blocking capability is enhanced by the neutron radiation and exhibits saturation at high flux (∼1012-1013 cm−2).