Enhanced Wettability of Cubic Boron Nitride Films by Plasma Treatment

Abstract

The wettability of hydrogen plasma-treated cubic boron nitride (cBN) films is studied. The films are prepared on Si substrates by inductively coupled plasma (ICP)-enhanced chemical vapor deposition, and further treated by pure hydrogen ICP and microwave plasma (MWP) separately. The surface roughness of the films and the cBN content in the films show only minor changes after the plasma treatment in any treatment condition. The contact angle of polar water and apolar 1-bromonaphthalene is reduced greatly with the ICP post-treatment, while it is reduced only moderately with the MWP post-treatment. The highly hydrophilic behavior with very low contact angles is attributed to a marked increase in the polar component of the apparent surface free energy up to 34 mJ/m2.