Total ionizing dose effect on 0.25 μm SOI NMOS is simulated in this paper. The simulated I-V characteristics curves for different total doses are in good agreement with experimental data. Total ionizing dose effects for various process parameters

such as doping concentration

silicon film thickness

buried oxide layer thickness and gate oxide layer thickness

are investigated under 104 Gy(Si) total ionizing dose for SOI NMOS. The results show that SOI NMOS with heavily doped thin gate oxide layer

appropriate thickness of buried oxide layer and thin silicon film is the best tolerant. The reasons are discussed. These are of help in device hardening design against total ionizing dose effects.