Radiation induced transconductance overshoot in the 130 nm partially-depleted SOI MOSFETs

Abstract

This paper presents the total ionizing dose (TID) radiation performances of core and input/output (I/O) MOSFETs from 130nm partially-depleted silicon-on-insulator (PDSOI). Both the core NMOS and PMOS are totally hardened to 1.5Mrad(Si), while the I/O devices are still sensitive to TID effect. The worst performance degradation is observed in I/O PMOS which is manifested as significant front gate threshold voltage shift and transconductance decrease. Contrary to PMOS, front gate transconductance overshoot is observed in short channel I/O NMOS after irradiation. A radiation induced localized damage model is proposed to explain this anomalous phenomenon. According to this model, the increments of transconductance depend on the extension distance and trapped charge density of the localized damage region in gate oxide. More trapped charge lead to more transconductance increase. These conclusions are also verified by the TCAD simulations. Furthermore, the model presents a way to extract the trapped charge density in the localized damage region.