Abstract
Diamond is one of the best SAW substrate candidates due to its highest sound velocity and thermal conductivity. But conventional diamond films usually express facet structure with large roughness. Ultra-nanocrystallined diamond (UNCD) films grown in a 2.45 GHz IPLAS microwave plasma enhanced chemical vapor deposition (MPECVD) system on Si (100) substrates in CH 4 -Ar plasma possess naturally smooth surface and are advantageous for device applications. Moreover, highly C-axis textured aluminum nitride (AlN) films can be grown by DC-sputtering directly on UNCD coated Si substrate. However, properties of UNCD films are much complex than microcrystalline diamond films, that is because this is a very complex material system with large but not fixed portion of grain boundaries and sp 2 /sp 3 bonding. Properties of UNCD films could change dramatically with similar deposition condition and with similar morphologies. A simple and quick method to characterize the properties of these UNCD films is important and valuable. Laser-induced SAW pulse method, which is a fast and accurate SAW properties measuring system, for the investigation of mechanical and structure properties of thin films without any patterning or piezoelectric layer. © 2007 Elsevier B.V. All rights reserved.