Refractory metal thin film having a particular step coverage factor and ratio of surface roughness

Abstract

In forming a metal or metal silicide film by CVD, a fluoro-silane is used as a reaction gas, or a fluoro-silane is added to a source gas. Examples of the metal halide used in the present invention include fluorides and chlorides of tungsten, molybdenum, titanium, tantalum and niobium. Among them, fluorides of tungsten and molybdenum are more desirable particularly from the viewpoint of the availability of the deposited metal or metal silicide. It is preferred that the source gases, i.e. silane series gas and metal halide, be diluted with a carrier gas such as nitrogen, hydrogen, helium or argon, and this is also true of the fluoro-silane. The total pressure is preferably 0.01 to 10 Torr. The reaction temperature is desirably 200.degree. to 800.degree. C., more desirably 300.degree. to 500.degree. C. Plasma CVD instead of thermal CVD may be employed for the purpose of lowering the reaction temperature.

Dependencies are inferred from the claim text.