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

摘要

We 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°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 is demonstrated to lead to high reliability, which includes TDDB and hot electron integrity.