Statistical Variability Analysis in Vertically Stacked Gate All Around FETs at 7 nm Technology

Abstract

In this paper, the statistical variability in the promoting gate all around field effect transistor (GAAFET) at 7 nm node is performed by 3D TCAD simulation. The effects of random variation sources, such as interface traps fluctuation (ITF), random dopants fluctuation (RDF), work function variation (WFV), and oxide thickness variation (TOXV), are analyzed through 500 investigated samples. A distinct variation dependence is found in fluctuation of DC characteristics. RDF is shown to have great influence on the drive current I _ON , while ITF, TOXV, and WFV are significant to fluctuate V _TH and SS in the subthreshold region. Besides, the sensitive of trap is detected for the optimization of ITF, and the interaction between ITF and TOXV strengthens the variation of subthreshold parameters.