Interfacial reaction of Mo-W alloys with silicon

Solid state contact reactions of thin films of Mo x W 100− x ( x =85, 57, 22) with silicon have been studied using Rutherford backscattering spectrometry, X-ray diffraction and scanning electron microscopy. Reactions and silicide formation were obtained by thermal annealing at temperatures between 450 and 900°C for all the alloys. No layer-by-layer phase separation was observed during silicide growth for the alloy-silicon reaction at these temperatures. The reaction temperature increased with increasing tungsten concentration in the alloys. Ion implantation of 4×10 15 cm −2 of silicon at 250 keV into Mo 57W 43/Si and Mo 22W 78/Si reduced their reaction temperatures and also made the reaction products more uniform.