The Effect of Number of Fins per Transistor on the TID Response of 12LP FinFET Technology

This article presents an analysis of the total ionizing dose (TID) response of n-channel transistors in the 12LP fin-based field effect transistor (FinFET) technology, with a focus on the impact of fin count per transistor. Previous studies, such as those by Vidana (2023), have shown increased off-state current ( $I_{\text {DS}-\text {off}}$ ) in n-channel FinFETs caused by charge buildup in shallow trench isolation (STI) oxides. However, these trends vary based on the number of fins used in the device. This work introduces a physics-based data-driven model supported by TCAD simulations to explain the fin count dependence on TID response. The model identifies variability in charge trapping in different STI regions, specifically highlighting the role of silicon nitride layers in mitigating leakage in devices with two or fewer fins. This research not only corroborates prior findings but also provides new insights into the electrostatic sensitivities unique to nanoscale FinFETs, offering a better understanding of TID effects and potential device hardening strategies.