The bias dependence of radiation-induced narrow-width channel effects (RINCEs) in 65-nm n-type metal-oxidesemiconductor field-effect transistors (NMOSFETs) is investigated. The threshold voltage of the narrow-width 65nm NMOSFET is negatively shifted by total ionizing dose irradiation, due to the RINCE. The experimental results show that the 65nm narrow-channel NMOSFET has a larger threshold shift when the gate terminal is kept in the ground, which is contrary to the conclusion obtained in the old generation devices. Depending on the three-dimensional simulation, we conclude that electric field distribution alteration caused by shallow trench isolation scaling is responsible for the anomalous RINCE bias dependence in 65nm technology.