Correlation between negative bulk oxide charge and breakdown: modeling, and new criteria for dielectric quality evaluation

Experimental evidence of the correlation between the negative bulk charge build-up in thin oxides and breakdown is presented. This charge corresponds to stress induced damage in the oxide. The evolution of the silicon interface charge is partly correlated with the bulk oxide degradation. The relative roles of the interfaces and the bulk in the wear-out process are described. A qualitative model for the oxide breakdown is proposed. The degradation rate of the bulk of the oxide layer and two ratios involving charge-to-breakdown values make better evaluation of the quality of the dielectrics and their interfaces possible. >