PURPOSE: To form a film having a uniform thickness over the entire surface of a base body in the stage of forming the film by a CVD method on the surface of the base material in a reaction vessel by expanding the sectional area of gaseous low material flow to the same area as the sectional area of the reaction vessel.
CONSTITUTION: A base material 1 to be formed thereon with a film by a CVD is disposed in a reaction vessel 2 and is heated to a prescribed reaction temp. by a heater. A gaseous raw material 4 for forming a film is simultaneously supplied through a nozzle 11 into the vessel. The gaseous raw material is decomposed on the surface of the heated material 1 and is deposited on the surface of said material, thus forming a coating layer thereon. Plural nozzle ports 12 for ejecting spirally gaseous flow 4 are provided on the side face of the nozzle 11 for supplying the material 4. Plural nozzles 13 are otherwise provided on the reaction vessel or a nozzle 14 packed with wool, etc. 16 in an ejecting port 15 having an expanded top end is used. The gaseous raw material 4 flows uniformly distributed over the entire surface of the body 1, thereby forming the film having a uniform thickness over the entire surface of the body 1.
OOI TOSHITSUGU
FUJITA FUSAO
