PURPOSE: To deposit by evaporation a hard film consisting essentially of a cubic crystal or wurtzite type boron nitride on a base plate by introducing boron- contg. gas and nitrogen-contg. gas respectively from supply electrodes into a vacuum and causing an ionization reaction by an arc discharge in the impression of a magnetic field.
CONSTITUTION: A filament 14 is heated by an AC power source to release thermoelectron and to generate an arc discharge between the filament 14 having zero potential and gas supply electrodes 15a, b having positive potential in a chamber 11 of a vacuum vessel 10. Boron-contg. gas and nitrogen-contg. gas are introduced respectively independently at a prescribed ratio from the electrodes 15a, b disposed at the center of the magnetic field generated by coil 19 in this state and are ionized. The ions are accelerated by a grid 13 connected to a negative high voltage power source so as to collide against a substrate S for vapor deposition maintained at negative potential and to bring the respective ions into reaction on the substrate S thereby forming a hard film consisting essentially of a cubic crystal and/or boron nitride of wurtzite type by vapor deposition on the substrate S.
TAKENO HIROSHI
ISHII MASAJI
