A solution of utilizing an N-rich SiON gate dielectric toward achieving highly reliable pMOS is demonstrated. The solution consists of a combination of two techniques: (1) a SiN-based gate dielectric with oxygen-enriched interface (OI-SiN) enabling nMOS and pMOS characteristics superior to plasma-nitrided oxides (PNO) and (2) a dual-core-SiON technique in which SiON in pMOS is selectively thickened by fluorine ion implantation to the poly-Si layer with the aim of acquiring NBTI immunity. The latter improved the NBTI immunity of pMOS with OI-SiN gate dielectrics to a level comparable to that with conventional PNO. Although the thickening of SiON using dual-core-SiON technique naturally decreases pMOS on-current, the performance remains superior to that with PNO