To provide a carbon based film which has both hardness and adhesion to a base material in combination, and to provide a carbon based film forming apparatus where the carbon based film can be formed with satisfactory productivity.
The carbon based film has a layer having a hydrogen concentration of ≤5 atom% and a layer having a hydrogen concentration of >5 to ≤15 atom% at least by one layer, respectively, wherein the layer on the side nearest to the base material is the layer having a hydrogen concentration of ≤5%. In the carbon based film, the concentration of hydrogen changes to the film thickness direction, a film part having the lowest hydrogen concentration of ≤5% and adjacent to the base material W is included, and the average hydrogen concentration in the film is 5 to <15%. The carbon based film forming apparatus for forming the carbon based film on the base material W, by evaporating a cathode 11 consisting mainly of carbon by vacuum arc discharge is provided. For keeping vacuum arc discharge at the arc current of ≤100 A, the apparatus has a gas introduction device G for introducing gas for arc stabilization into the existing region of the cathode and/or a reactance component generation circuit R between an arc power source 13 and the cathode 11.
OKAMOTO YASUO
FUJINAMI YASUSHI
