Modeling of ionizing radiation-induced degradation in multiple gate field effect transistors

The radiation response of advanced non-planar multiple gate field effect transistors (MuGFETs) has been shown to have a strong dependence on fin width (W). A scalable analytical model that can describe the radiation response of MuGFET devices as a function of W is presented here. A set of extracted parameters are used in conjunction with the closed-form expressions for the surface potential, thereby enabling accurate modeling of radiation-induced degradation of the I-V characteristics for these devices as a function of W. Total ionizing dose (TID) experiments are used to analyze and validate the modeling approach presented in this paper.

I. Introduction

The limits of scaling for the classical “bulk” MOSFET are drawing closer. Short-channel effects (SCE) caused by the decreasing distance between the source and the drain reduce the ability of the gate to control the potential distribution in the channel region [1]. MOSFETs fabricated in silicon-on-insulator (SOI) technologies can result in better control of SCEs. Depending on the Si film thickness , the buried oxide (BOX) thickness and doping concentrations, SOI devices can achieve superior electrical response compared to their bulk counterparts. SOI MOSFETs have also been shown to improve hardness to transient radiation effects [1]. Both standard planar SOI devices and advanced non-planar multiple gate field effect transistors (MuGFETs) are considered for these advantages. Shown in Fig. 1 is a cross-sectional TEM image of a typical non-planar MuGFET device, the FinFET [2]. The figure shows that the body of the FinFET is almost entirely surrounded by the gate terminal. The BOX layer dielectrically isolates the device from the substrate, which significantly reduces the sensitive volume for transient radiation-induced charge collection [1]. Fig. 1.

Cross-sectional tem image of a non-planar (finfet) device [2]