NH3-RTP grown ultra-thin oxynitride layers for MOS gate applications

RTP grown oxynitride layers were applied to NMOS transistors as gate dielectrics and their device performances were compared with those prepared by RF plasma nitridation (RF-PN). Transistors with RTP-grown oxynitride gate show a significantly better uniformity in threshold voltage on 200 mm wafers than those oxynitride layers grown by RF-PN. It was also found that the leakage currents of the RTP and RF-PN gate oxynitrides obey the same trend from the 1.5 nm EOT regime down to the 1.0 nm EOT regime. This observation indicates that the leakage current barrier quality of the RTP oxynitride is at least as good as the RF-PN oxynitrides.