Formation Mechanisms of the Deformed Oxide Layer in a Tungsten Polycide Structure

Abstract

Destructive oxidation mechanisms in a tungsten polycide structure were investigated. In the experiments, the dependencies of the variation in the process flow, structural variations and annealing temperature application on the formation of destructive oxidation were examined. Surface and structural analyses were performed using a variety of analytical techniques such as transmission electron microscopy. The deformed oxide layer, having a pathological morphology of the oxide surface, was formed on the silicide layer during the oxide process after the removal of the surface layer of silicon oxide that initially covered the crystallized silicide film. It was revealed that destructive oxidation resulted from the formation of volatile metal-oxides, which originated during the process of low temperature annealing in ambient O2.