Session 5A-4

V_FB Roll-off in HfO₂ Gate Stack after High Temperature Annealing Process
- A Crucial Role of Out-diffused Oxygen from HfO₂ to Si -

 

Abstract

We report for the first time that VFB roll-off behavior observed in thinner EOT region for metal/HfO2/SiO2 stacks is directly related to re-oxidation at the bottom SiO2/Si interface. Based on this understanding, we propose a possible solution for keeping high effective work-function without VFB roll-off and demonstrate the obtained effective work-function value of 4.9eV in Pt3Si/HfO2/SiO2 stack.