Drain biased TDDB lifetime model for ultra thin gate oxide

For drain biased TDDB, hole injection enhanced gate oxide degradation has been discussed and modeled, and the model is in excellent agreement with the experimental data. Although hole injection will degrade gate oxide, lifetime of drain biased TDDB is better than gate bias due to stress area difference and strong area dependence (/spl beta/ is small) for ultra thin gate oxide; however, it may become a concern for thick oxide for drain bias.