Investigation of Work Function Variation on the Electrical Performance of sub-7nm GAA FETs

Abstract

This paper presents the impact of work function variation (WFV) in Gate-All-Around Field Effect Transistors (GAA FETs) using the technology computer-aided design (TCAD) tool for sub-7nm high-performance logic applications. We have compared the WFV induced electrical characteristic variations in nanowire (NW) and nanosheet (NS) GAA FETs. We study the impacts of different grain sizes on the performance of NSFET and NWFET using statistical data analysis. The variation in critical electrical figures-of-merit (VTH, ION, IOFF, SS, and DIBL) have been analyzed. It is predicted that the NSFET shows improved immunity toward VTH variation than NWFET. Overall, the NSFETs are less prone to performance variations compared to NWFET. As such NSFET architectures will be the preferred choice for logic devices below sub-7nm technology nodes.