Impact of electrode-side chemical structures on electron mobility in metal/HfO/sub 2/ MISFETs with sub-1nm EOT

Extremely high (247cm/sup 2//Vs at peak) electron mobility has been obtained by sub-1 nm EOT of n-metal/HfO/sub 2/ MISFET with well-controlled metal/HfO/sub 2/ interface. It was found that Coulomb scattering due to nitrogen induced fixed charge degrades the mobility by analyzing the chemical structures of the metal electrode/HfO/sub 2/ interface using backside XPS. Based on a consideration of this result, high-performance nMISFET has been fabricated by using nitrogen-free TaSix (/spl Pi//sub m/spl I.bar/eff/=4.36eV on HfO/sub 2/) as the gate electrode.