Patent ID: 8420043

Claim:
A method for manufacturing a nano-crystal diamond film, the method comprising: forming a nano-crystal diamond film on a substrate by means of a plasma CVD method using a raw material gas comprising hydrocarbon, hydrogen, and at least one additive gas selected from the group consisting of hydrogen sulfide, carbon dioxide and oxygen, the substrate being placed outside a plasma region and downstream of the raw material gas flow from the plasma region, the nano-crystal diamond film containing at least one impurity selected from the group consisting of sulfur, boron and oxygen doped with a concentration of 10 16 to 10 21 /cm 3 , not less than 80% of crystal grains in the nano-crystal diamond film being constituted by crystal grains having a grain diameter ranging from 1 nm to not more than 1000 nm; and subjecting the nano-crystal diamond film to a hydrogen plasma treatment using microwave or high-frequency power or a chlorinated gas plasma treatment using microwave or high-frequency power to terminate a surface of the nano-crystal diamond film with hydrogen atoms or chlorine atoms.