Radiation Response of H-Gate DSOI nMOSFETs: Channel Size Dependence on TID Degradation

To enable precise application of back-gate biasing for radiation hardening in double silicon-on-insulator (DSOI) technology, it is essential to evaluate the variation in total ionizing dose (TID) response under different channel size conditions. This paper investigates the influence of channel sizes on TID response in H-gate DSOI nMOSFETs. The experimental results indicate that shorter-channel devices exhibit higher TID sensitivity at low-to-medium doses but demonstrate a significant threshold voltage rebound at high doses. Furthermore, under short-channel conditions, increasing the channel width aggravates degradation, resulting in an anomalous radiation-induced wide channel effect. The 3D TCAD simulation is carried out to further analyze the size-dependence phenomena. Simulation results highlight that channel sizes modulate the local electric field distribution within the buried oxide, thereby influencing the density and spatial evolution of radiation-induced trapped charges. Finally, charge extraction via the mid-gap and DCIV techniques confirms the differences in trapped charge density and provides a mechanistic explanation for the rebound effect.