Enhanced hot-hole degradation in P/sup +/-poly PMOSFETs with oxynitride gate dielectrics

A significant degradation under hot-hole injection is observed in P/sup +/-poly PMOSFETs with oxynitride gate dielectrics. Both oxynitrides formed by gate oxide grown on Nitrogen Implanted Si Substrates (NISS) and NO-annealed SiO/sub 2/ oxynitride gate dielectrics are used and compared to control SiO/sub 2/ gate dielectrics of identical thicknesses. A physical model responsible for such enhanced degradation in PMOSFETs with oxynitride gate dielectric is proposed. It is shown that the hole injection barrier lowering as a result of the nitrogen-rich layer at the SiO/sub 2//Si interface in oxynitride is responsible for such enhanced degradation.