PURPOSE: To increase the speed of gas evacuation, by providing a shielding plate in a titanium evaporator to keep titanium from clinging to all the inside of a vacuum vessel, and by making the surface of the shielding plate so rough as to have numerous projections and recesses.

CONSTITUTION: Titanium 4 vaporized from the tip 3a of a chip evaporator 3 clings to the inside of a vacuum vessel, with which plasma P does not come into contact. Therefore, the clinging titanium 4 and the plasma P do not interact with each other. Because of the adsorbing action of the clinging titanium, the whole interior of the vacuum vessel 1 is put in a high degree of vacuum. Since the surface of a shielding plate 5 is provided with projections and recesses, the surface area of the plate 5 is increased to heighten the speed of gas evacuation.