Statistical Simulations for Flash Memory Reliability Analysis and Prediction

Abstract

In this paper, through the use of a recently proposed statistical model of stress-induced leakage current, we will investigate the reliability of actual flash memory technologies and predict future trends. We investigate either program disturbs (namely gate and drain disturbs) and data retention of state-of-the-art flash memory cells and use this model to correlate the induced threshold voltage shift to the typical outputs coming from oxide characterization, that are density, cross section, and energy level of defects. Physical mechanisms inducing the largest threshold voltage (V/sub T/) degradation will be identified and explained. Furthermore, we predict the effects of tunnel oxide scaling on flash memory data retention, giving a rule of thumb to scale the tunnel oxide while maintaining the same retention requirements.