Modified Percolation Model for Polycrystalline High-$ \kappa$ Gate Stack With Grain Boundary Defects

Abstract

We modify the existing oxide breakdown (BD) percolation model in this letter to account for the presence of microstructural weakest link grain boundary (GB) defects in polycrystalline high-κ (HK) gate stacks. The different rates of the stress-induced leakage current degradation and oxide trap generation at the bulk and GB regions need to be accounted for in modeling the statistical nature of BD in HK dielectric thin films. Simulated results reveal the dominance of GB-related failures and the origin of the non-Weibull stochastics inherent in polycrystalline HK stacks. We also point to the inability of conventional percolation models with an assumed uniform defect generation to describe the failure statistics of current HK gate stacks.