Abstract
Boron-Carbon-Nitrogen (BCN) films are deposited on Si (100) substrates by RF sputtering with a mixture of Ar and N2 gases using a target of graphite combined with semi-circled boron carbide (B4C). A couple of the films located at the positions faced to B4C (BC) and graphite (G) sides are prepared at the same time, and their microstructure and mechanical properties are examined against the substrate bias modes, DC, uni- and bipolar pulses. The films are also examined as a function of the duty cycle in unipolar pulse. The results show that the concentration of C in the G side films is larger than those of the BC side films. For the unipolar pulse mode, the composition and the surface morphology are not significantly affected by the duty cycle. However, the maximal of the mechanical properties of the G side film in hardness and wear resistance are obtained at the duty cycle of 500 micro s. For the bipolar pulse mode, h-BN phase is increased in amount as compared with the unipolar pulse mode. In addition, the B concentration is increased and the mechanical properties are decreased in the BC side films, while, the N concentration is increased and the mechanical properties are increased in the G side films. These effects of the bipolar pulse mode are similar to those of the negative DC mode.
