Nitrogenated amorphous carbon films prepared by unbalanced magnetron sputtering for high recording density media

Carbon coatings are currently used as a smooth and protective coating on the magnetic disk and head against wear and corrosion as well as against local charging. The rapidly increasing storage density of magnetic thin film media will soon require carbon overcoats of only 2 nm or less in thickness. Nowadays, most of carbon coatings are prepared by conventional magnetron sputtering (CMS) because of the high deposition rate and homogeneity of the films. Several attempts have been reported to improve the hardness and wear resistance of carbon overcoats. The incorporation of nitrogen in amorphous carbon films has shown positive influence on the scratching resistance of carbon film. Amorphous carbon film prepared by unbalanced magnetron sputtering (UBMS) was reported to have a hardness of 24 GPa. The use of unbalanced magnetron configurations allows high ion currents to be transported to the substrate so that coatings of excellent quality can be deposited. In this digest, nitrogenated amorphous carbon films were synthesized by UBMS. The film structures and mechanical properties of the films were investigated as a function of N₂/Ar flow rate ratio.