Nitrogen concentration optimization for down-scaled CMOSFET with N/sub 2/O-based oxynitride process

The characteristics of dual gate CMOSFETs with oxynitride gas dielectrics were studied, and the optimization for nitrogen concentration (C/sub N/) in oxynitride film was systematically carried out. It was clarified that the required C/sub N/ for suppressing boron penetration in pMOSFET can be drastically decreased by using BC as a gate dopant instead of BF/sub 2//sup +/. Furthermore, it was found that the introduction of excess nitrogen results in the unique behaviour of short channel characteristics degradation in nMOSFET for the first time, and it becomes one of the limiting factor for nMOSFET miniaturization.