Relation between Stress-Induced Leakage Current and Dielectric Breakdown in SiN-Based Antifuses

Abstract

We report on the degradation process of metal-to-metal antifuses that use thin silicon nitride film as the dielectric layer under high electric field stress. Stress-induced leakage current was observed in all samples, and it flows through local spots. Two-level fluctuations were found on the leakage current well below the stress voltage, and large and complex fluctuations were observed near the stress voltage. The conduction mechanism of the stress-induced leakage current was the Poole-Frenkel type. It was found that the dielectric constant of the path became large and that the breakdown and the anomalous current depended on the barrier metal thickness. Considering these results, the stress-induced leakage current and the breakdown are thought to be caused by electromigration of electrode material to the SiN film.