Nickel-silicide phase effects on flatband voltage shift and equivalent oxide thickness decrease of hafnium silicon oxynitride metal-silicon-oxide capacitors

This Letter reports the nickel-silicide phase effects on the electrical characteristics of high-$k$ and silicon dioxide $(SiO2)$ metal-oxide-semiconductor devices. It was found that the silicon-deficient nickel-silicided gate electrode on the hafnium silicon oxynitride (HfSiON) led to a positive flatband voltage $(Vfb)$ shift and a reduction in the equivalent oxide thickness (EOT). However, negligible $Vfb$ shift and EOT decrease were observed in the case of control hafnium oxide and $SiO2$ structures. It was believed that Si dissociation from the HfSiON layer was the main reason for the positive $Vfb$ shift and the EOT decrease.