The impact of ultrathin nitrided oxide gate-dielectrics on MOS device performance improvement

The device performance including mobility mu /sub eff/ under high effective normal field E/sub eff/ and switching speed under high gate drive V/sub G/-V/sub T/ at 298 and 82 K is studied in MOSFETs with the nitrided-oxide system. At 298 K, mu /sub eff/ of SiO/sub 2/ is degraded much faster with increasing E/sub eff/ over approximately 0.5 MV/cm than that of nitrided oxide, where mu /sub eff/ alpha E/sub eff//sup -1/3/. The improvement is much more pronounced at 82 K. As a result, the mu /sub eff/ at E/sub eff/=1 MV/cm is much larger by 30(50)% than that of SiO/sub 2/ at 298 (82) K. For improving high-field mu /sub eff/ over SiO/sub 2/, light nitridation is found to be crucial. Rapid nitridation greatly improves current drivability and circuit switching speed under high V/sub G/-V/sub T/. An ultrathin (reoxidized) nitrided oxide significantly reduces the major scaling limitation for MOS device performance improvement in place of gate-SiO/sub 2/.<>