PURPOSE: To form a chemically stable tungsten nitride film by containing compound including nitrogen and halogenated tungsten in material gas to scarcely react silicon with silicon oxide.

CONSTITUTION: Tungsten hexafluoride diluted with argon gas and ammonia are used as material gases, set at 10-3W20 Torr of pressure at 300W1000°C of substrate temperature. Then, a reaction of 2WF6+4NH3→2WN+N2+12HF occurs on a silicon substrate 103 to form a tungsten nitride film. When hydrogen is added to the gas, a reaction of 2WF6+2NH3+3H2→2WN+12HF occurs to also obtain a tungsten nitride film. The film thus obtained has an amorphous or fine crystal structure so that the surface is smooth. lts step coverage is good, and the uniformity in the surface is preferable.