Reliability degradation of high density DRAM cell transistor junction leakage current induced by band-to-defect tunneling under the off-state bias-temperature stress

The band-to-defect tunneling (BDT) induced junction leakage current of high density DRAM cell transistors under off-state bias-temperature (B-T) stress was studied in detail for the first time. It was found that the BDT leakage current is most critical for limiting the cell transistor scaling. The new off-state B-T stress was proven to be a very effective reliability assessment tool for leakage current degradation of the DRAM cell transistor. It was also found to be useful for assessing reliability degradation of future high density DRAMs.