Chemical effects in cold-wall LPCVD of tungsten

Abstract The reaction between WF 6 and Si was studied in a cold-wall reactor. Although the process appears to be self-limiting, it displays an Arrhenius-type behaviour which would correspond to an apparent activation energy of 0.33 eV. RBS analyses revealed that W deposition is accompanied by a 1.5 to 3 times larger Si consumption. The deposition process is found to be sensitive to the presence of nearby reactive surfaces. A model for W deposition on Si is presented in which Si transport through a porous layer is proposed to determine the ultimate W film thickness.