Characteristics of w-doped nanocrystalline carbon films prepared by pulsed dc unbalanced magnetron sputtering

Tungsten-doped carbon films were deposited via a pulsed direct current unbalanced magnetron sputtering system, with tungsten and graphite targets. Tungsten was used as the doping material in carbon thin films for the surface coating application. The structural, surface, and electrical properties of the WC films fabricated with various pulse frequencies were investigated. The films showed a uniform and smooth surface. The root mean square surface roughness decreased and the contact angle increased with the increase in pulse frequency. The resistivity of the tungsten-doped carbon films decreased as a function of pulse frequency. The surface and electrical properties of the films were improved with an increase in pulse frequency. These results are associated with the nanocrystalline tungsten-doped carbon phase and sp² clusters in carbon networks, which increased with the kinetic energy of the ions as a result of the increasing pulse frequency.