Formation mechanism of the multilayered-structure barrier of WNx/Si(100)

The chemical bonding states, microstructure, and the formation mechanism of an interfacial layer between WNx/Si(100) treated by rapid thermal annealing at various temperatures were investigated. It was found that the ultrathin interfacial layer had the multilayered structure of SiO2/SiOxNy/nano-WSi2. The interfacial silicon nitride layer formed by lower annealing temperatures was converted into an oxide layer by increasing the annealing temperature. The thickness of the interfacial oxide layer increased from ∼34 to ∼50 A with the annealing temperature. It was found that the interfacial layer played a role as a barrier against silicidation between W and Si(100) up to 1000 °C.