Surface acoustic wave properties of natural smooth ultra-nanocrystalline diamond characterized by laser-induced SAW pulse technique

• Published in: Diamond and related materials Vol. 17; no. 4; pp. 446 - 450
• Main Authors: Lee, Y.C., Lin, S.J., Buck, V., Kunze, R., Schmidt, H., Lin, C.Y., Fang, W.L., Lin, I.N.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2008; Elsevier
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Laser-induced SAW pulse technique; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nano-diamond; Physical properties of thin films, nonelectronic; Physics; SAW; Specific materials; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thermal stability; thermal effects; Thin film structure and morphology; UNCD; SAW; Laser-induced SAW pulse technique; UNCD; Nano-diamond; Grain boundaries; Methane; Synthetic diamond; Roughness; Acoustic surface waves; Laser irradiation; Surface states; Thin films; Ultrananocrystalline diamond; Thermal conductivity; PECVD; Bonding; Radiation effects; Crystal defects; Patterning; Aluminium nitride; Mechanical properties; Electronic structure; Piezoelectric materials; Morphology; Sputter deposition; Microwave discharge
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2007.08.025

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.