Mechanical stress impact on nanosheet device performance

Abstract

The impact of mechanical stress on nanosheet (NS) nFETs in the linear region is investigated using nanoindenter-based electrical measurements combined with finite element method (FEM) and TCAD simulations. Localized mechanical stress applied by a nanoindenter results in increases in both the on-state current (Ion) and off-state leakage current (Ioff). The stress-induced Ion enhancement is attributed to the piezoresistive effect, and piezoresistive coefficients are quantified by correlating experimental resistance changes with FEM-derived channel stress. The extracted intrinsic NS coefficient is significantly smaller than that of bulk n-type Si due to short-channel effects and strong quantum confinement. TCAD simulations further suggest that the Ioff increase is governed by stress-enhanced trap-assisted tunneling, driven by stress-induced bandgap narrowing at the drain-substrate junction.