Compact Modeling of Radiation Effects in Thin-Layer SOI-MOSFETs

Radiation can generate huge amounts of carriers in thin-layer SOI-MOSFETs, which change the device-internal potential distribution, known as an origin for of malfunction of circuits. 2D-numerical device-simulation analysis shows that the radiation-generated electrons initially flow-out from the SOI layer to both source and drain electrodes, which moderates the radiation-effect magnitude on device currents in this beginning stage. Subsequent enhancement of the current flow is due to accumulated holes caused by the potential barrier at source/channel junction. Compact modeling of the carrier movements during the initial radiation stage and of the hole-accumulation dynamics is based on the dynamically generated carrier densities. The developed compact model has been implemented into SPICE and model evaluation has been done by comparison to 2D-numerical device-simulation results. Under the off-state, it is shown that circuits can be easily switched to operation condition. Under the on-state, it is demonstrated that circuits can easily malfunction by operating differently from the designed circuit function. Though the radiation itself happens only for a short time, the radiation-induced effects continue for a rather time long, which causes serious effects in the circuits and is explained by the capacitor features of the SOI-MOSFET