Silicide‐Silicon Interface Degradation during Titanium Silicide/Polysilicon Oxidation

Abstract

We have investigated the silicide‐silicon interface during the oxidation of titanium silicide on polysilicon. We find that during oxidation the polysilicon layer under the silicide is consumed inhomogeneously and that at the same time the titanium silicide moves into the polysilicon layer. Oxidations were carried out both in wet and dry with similar results. This nonuniform consumption of the polysilicon layer appears to be related to the condition of the silicide‐silicon interface prior to the oxidation step. This effect can result in the reduction of the dielectric breakdown strength of underlying gate oxide in titanium silicide/polysilicon/oxide/Si structures.