New gate oxide wear-out model for accurate device lifetime projections on vertical drain NMOSFET

In this paper, the reliability of the vertical drain NMOS (VDNMOS) device structure has been evaluated for a state of the art CMOS process. In past technologies, reliability was restricted by hot carrier degradation effects. With technology scaling, gate oxide wear-out has become the reliability limiter. A new VDNMOS oxide wear-out model has been developed and verified with low voltage stress data. This new model accurately captures the dependence of VDNMOS lifetime on drain to gate bias and can be used to better project the maximum drain voltage at operating condition.