Regensburg 2004 – scientific programme

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DS: Dünne Schichten

DS 6: Spezielle Schichten II

DS 6.1: Talk

Monday, March 8, 2004, 10:15–10:30, HS 32

Mechanical Stability of Nanocrystalline Diamond Films on Silicon — •Giuseppe Bregliozzi, Werner Haenni, and Henry Haefke — CSEM Swiss Center for Electronics and Microtechnology, Inc., Rue Jacquet-Droz 1, CH-2007 Neuchatel, Switzerland

Diamond is an excellent film material due to its outstanding hardness, thermal conductivity and chemical stability and low friction when sliding against itself. In many specific applications (e.g. electrodes and MEMS), these outstanding properties make diamond the best choice. A limiting feature, however, is that only very few support materials have the necessary affinity to stick to diamond: silicon carbide, silicon nitride, silicon as well as refractory carbides. Even with these materials, testing diamond film affinity is a problem due to its superb mechanical properties. This work shows that an excellent technique to test film affinity is to use cavitation erosion, which probes the properties of diamond films under dynamic conditions. In this work, two types of silicon with different surface topographies have been tested for their suitability as a support for a nanocrystalline diamond film. It was found that the surface roughness of the substrate has a strong influence upon the cavitation erosion behavior. Higher roughness results in the presence of more defect sites. Wear damage of the diamond films initiate from these film defects, which then rapidly propagate across the entire film surface. The microwear mechanism of the examined diamond film is characteristic of brittle materials and occurs without any visible deformation as is commonly observed in metals.