AVS 45th International Symposium
    Vacuum Metallurgy Division Tuesday Sessions
       Session VM+TF-TuM

Paper VM+TF-TuM4
AlN/cBN Magnetron Sputtering: Effects on Adhesion and Phase Stabilization

Tuesday, November 3, 1998, 9:20 am, Room 328

Session: Advances in Hard and Superhard Coatings
Presenter: W. Otaño, Pennsylvania State University
Authors: W. Otaño, Pennsylvania State University
L.J. Pilione, Pennsylvania State University
R. Messier, Pennsylvania State University
J.J. Santiago-Avilés, University of Pennsylvania
G. Lamaze, National Institute of Science and Technology
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The deposition of cubic boron nitride (cBN) thin films is of interest from a technological and fundamental point of view. It has been well established that the cubic phase stabilization depends on the energetic bombardment of the growing film. As a result of this bombardment the films show high stress levels that eventually produce delamination from the substrate. It is therefore interesting to consider atomic additions and compliant interfaces as alternative pathways to reduce the cBN stress level and/or improve film adhesion. With this purpose cBN thin films were co-deposited with Al reactively sputtered. The effects of the addition of aluminum and/or the use of AlN interlayers in the stabilization and adhesion of cBN films will be presented. The BN films were deposited by rf unbalanced magnetron sputtering and the substrate was biased using a low frequency dc pulsed excitation signal. Films with over 70% of the cubic phase, as measured by FTIR, were deposited at low negative bias voltages. A second dc pulsed power supply was used to reactively sputter the aluminum. AlN was added as an interlayer between the substrate and the BN film as well as co-deposited at different sputtering powers. The films were analyzed by FTIR, RBS and neutron depth profiling. It was found that the addition of Al to the BN films leads to a destabilization of the cubic phase for AlxB1-xN compositions above x=0.04. AlN interlayers deposited at specific pressures were found to prevent the delamination of the cBN films. A 0.7 micron multilayer coating of AlN/cBN was prepared that did not delaminate from the substrate.