PVD-HfSiON gate dielectrics with Ni-FUSI electrode for 65nm LSTP application

HfSiON gate dielectrics are fabricated by oxidation of co-sputtered Hf and Si, followed by nitridation with NH3 gas. It is found that HfSiO film stays in an amorphous state after oxidation, while HfO2 film tends to crystallize. Due to its thermally robust properties of HfSiON, lower gate leakage and good uniformity are achieved even after high thermal treatment (above 1000 °C). A reduction in capacitance due to lower permittivity is compensated by the introduction of a Ni-FUSI electrode, where improved inversion capacitance leads to a higher on-state drive current.