Newly Found Anomalous Gate Leakage Current (AGLC) for 65 nm Node and Beyond, and Its Countermeasure Using Nitrogen Implanted Poly-Si

We found a new anomalous gate leakage current (AGLC) of ultra-thin gate-SiON, which may directly impact standby leakage and yield for 65 nm node and beyond. We have identified the AGLC mechanism and also developed gate-stack fabrication process as effective countermeasures. Reducing gate-SiON to less than 1.3 nm induces AGLC leading to reliability degradation in nFET. With relatively large Phosphorous doping of gate electrode, gate length larger than 0.1 mum and very large total width comparable to product level, AGLC can be observed even in 1.3 nm gate-SiON which is a typical gate dielectric thickness for 65 nm node. Nitrogen implantation into poly-Si suppresses AGLC and effectively prevents the reliability degradation while boosting drivability as the poly-Si grain size is reduced. For suppression of AGLC for even thinner gate-SiON of 1.1 nm, additional poly-Si/SiON fabrication process optimization has been implemented