AN ANALYTICAL MODELING TO STUDY THE RADIATION EFFECTS IN UNDOPED SILICON NANOWIRE GATE-ALL-AROUND (GAA) MOSFET

Abstract

The reliability of ultrathin multi-Gate MOS devices is an important issue for novel nanoscale CMOS technologies, in the radiation environment, the degradation of device performance of the nanowire Gate-All-Around (GAA) is a major reliability concern for space and terrestrial applications. Therefore, we present an analytic degradation model of undoped NW GAA MOSFET considering the effects of radiation induced interface trap charge (INTC) density. In this model, a two dimensional Poisson equation including the mobile charge carriers is solved. The model analysis shows that the localized INTC density affects the position of minimum potential point in the channel region, and the radiation induced degradation become severe with the shorter channel lengths. The variation in degradation mechanism of surface potential and threshold voltage of the GAA MOSFET, with ditferent polarities of the INTC density, fixed and varying length of damaged zone, and with various diameters of NW channel are also modeled. We find from the analytical results of the proposed model, that the larger degradation in device performance is caused by negative INTC density. And these eflcts become dominant with short channel lengths and for thinner NW channel. 'ihe obtained analytical results show a good agreement with the TCAD device simulator over a wide range of device parameters. This highlights model accuracy and provides crucial insights for radiation tolerant NW GAA MOSFETs design.