TID Circuit Simulation in Nanowire FETs and Nanosheet FETs

Abstract

In this study, the effects of the total ionizing dose (TID) on a nanowire (NW) field-effect transistor (FET) and a nanosheet (NS) FET were analyzed. The devices have Gate-all-around (GAA) structure that are less affected by TID effects because GAA structures have better gate controllability than previously proposed structures, such as planar MOSFETs and FinFETs. However, even for GAA devices with the same channel cross-sectional area and equivalent oxide thickness, structural differences can exist, which can result in different tolerances of TID effects. To observe the device and circuit operation characteristics of these GAA devices with structural differences, n-type and p-type devices were designed and simulated. The circuit simulation according to TID effects was conducted using Berkeley short-channel insulated-gate FET model (BSIM) common multi-gate (CMG) parameters. The NS-FET generated more VT shift than the NW-FET because the NS-FET had a wider gate oxide area and channel circumference, resulting in more interface hole traps. The abnormal VT shift leads to causing unstable circuit operation and delays. Therefore, it was confirmed that the ability of the NW-FET to tolerate TID effects was better than that of the NS-FET.