Optimization of gate leakage and NBTI for plasma-nitrided gate oxides by numerical and analytical models

Abstract

Reduction in static-power dissipation (gate leakage) by using nitrided oxides comes at the expense of enhanced negative-bias temperature instability (NBTI). Therefore, determining the nitrogen content in gate oxides that can simultaneously optimize gate-leakage and NBTI degradation is a problem of significant technological relevance. In this paper, we experimentally and theoretically analyze wide range of gate-leakage and NBTI stress data from a variety of plasma-oxynitride gate dielectric devices to establish an optimization scheme for gate-leakage and NBTI degradation. Calculating electric fields and leakage current both numerically and using simple analytical expressions, we demonstrate a design diagram for arbitrary nitrogen concentration and effective oxide thickness that may be used for process and IC design.