POLYCRYSTALLINE DIAMOND FILMS FOR ACOUSTIC-WAVE DEVICES

A laser ultrasonics technique has been used to measure acoustic wave v elocities in polycrystalline CVD diamond for the first time. Lamb (pla te) waves propagate with very high velocities in the range 8700-12 200 m s(-1); the lowest values are recorded for films with the lowest cry stal quality and highest non-diamond content. High-quality films with differing crystal textures [(100), (110)] or thickness (250-535 mu m) show little variation. The results are discussed in terms of the fabri cation of a high-sensitivity flexural plate wave (FPW) device for sens ing applications in hostile environments. (C) 1998 Elsevier Science S. A.