Patent ID: 6858969
Filing Date: 2005-02-22
Classification: H03H

Abstract:
1. A surface acoustic wave (SAW) device which comprises: (a) a substrate having a surface which has been processed to allow enhanced nucleation of diamond; (b) a nominally unpolished nanocrystalline diamond film deposited on and adhered to the surface of the substrate and having a diamond grain size distribution between 1 nm and 50 nm wherein the nanocrystalline diamond film is formed in a microwave reactor containing argon, with a concentration of 90% by volume or greater, methane and optionally hydrogen at a pressure between 50 and 300 Torr at a flow rate between about 50 and 600 sccm, and a temperature of the substrate of 600° to 800° C., essentially in the absence of nitrogen or oxygen; (c) electrodes deposited on the diamond film, or the piezoelectric overlayer, as interdigitated elements; and (d) a piezoelectric composition coated over the diamond and electrodes, or with electrodes atop the piezoelectric composition, wherein the surface acoustic wave is created on the diamond by electrical waves supplied to the electrodes which strain the piezoelectric composition to produce the surface acoustic wave on the diamond, wherein the SAW device has acoustic wave velocities which have a close correspondence to calculated velocities based upon single crystal diamond values.