Formation Mechanism of Metal-Oxides on Plasma-Exposed Wsi/Poly Si Gate Stacks

Abstract

The formation mechanism of deformed tungsten oxides (WOx, x=2,3) on WSix/poly Si gate stacks has been investigated. It was revealed that plasma etching process introduced oxygen impurity into WSix surface and caused the WOx formation during the subsequent thermal oxidation. WSix films preferred corientation were found to be stable in the oxidation process after plasma etching process.