Abstract
Ti-doped amorphous carbon (a-C) films have been prepared on silicon substrates by DC magnetron sputtering. The adhesive strength of the a-C film and Ti-doped a-C films were measured by scratch tests. The Ti-doped a-C films prepared at 250°C had almost constant values of critical load in the scratch tests irrespective of the Ti concentration. The adhesion of Ti-doped a-C film with high Ti concentration was markedly improved by heat treatment in a vacuum, and the critical loads of the films containing 15 at.% Ti increased from 180 mN to 400 mN. Furthermore, the critical loads of the Ti-doped a-C films increased with increasing deposition temperature. The heat-treated Ti-doped a-C films deposited at 350°C had the maximum critical load of 500 mN. The apparent increase in critical load is caused by the chemical interaction between Ti and the substrate material.
