Junction leakage current degradation under the off-state bias-temperature stress: a new reliability assessment method for high-density DRAMs

A new reliability assessment method on retention time failure for high-density DRAMs under off-state bias-temperature (B-T) stress was suggested and investigated using the well-known gated-diode test pattern. The transistor junction leakage current degradation, total junction leakage current especially including gate-induced drain leakage (GIDL) component, under the off-state B-T stress was found to be more sensitive than widely-used gate-oxide degradation under the Fowler-Nordheim (F-N) tunneling stress. The off-state bias stress also gives significantly higher degradation on the gate-oxide stress-induced leakage current (SILC) than F-N tunneling current stress. The features of the off-state B-T stress which gives stress to almost all transistor leakage components and the mechanism of the junction leakage current degradation under the off-state bias condition were discussed.