Ultra-thin (T/sub eff/ /sup inv/ = 1.7 nm) poly-Si-gated SiN/HfO/sub 2//SiON high-k stack dielectrics with high thermal stability (1050/spl deg/C)

摘要

Demonstrated the high-performance and high-reliability of ultra-thin poly-Si-gated SiN/HfO/sub 2//SiON high-k stack dielectrics. A SiN layer deposited on HfO/sub 2/ is shown to be indispensable to the suppression of the reaction of poly-Si and HfO/sub 2/, resulting in high thermal stability (1050/spl deg/C). This thermally stable SiN/HfO/sub 2//SiON structure can achieve an ultrathin oxide thickness of T/sub eff//sup inv/ (effective oxide thickness measured in strong inversion region) for 1.7 nm, which is less than 1 nm for EOT. A low leakage current of 5 to 6 orders of magnitude lower than that of SiO/sub 2/ was observed. In addition, this thermal stability can lead to high reliability, which includes TDDB and hot electron integrity.