Diamond substrate having piezoelectric thin film, and method for manufacturing it

摘要

Further improvements in circuit-element performance of surface-acoustic wave devices are anticipated by being able to produce a diamond substrate on which is formed a Li(NbxTa1-x)O3 (wherein 0<=x<=1) thin film whose c-axis orientation is favorable and whose piezoelectric characteristics are satisfactory. A diamond substrate on which a highly c-axis oriented, piezoelectrically satisfactory Li(NbxTa1-x)O3 (wherein 0<=x<=1) thin film is formed can be obtained by using a laser ablation technique to form a Li(NbxTa1-x)O3 (wherein 0<=x<=1) thin film onto a (110)-oriented gas-phase synthesized polycrystalline diamond substrate, that is superficially mirror-surface processed and superficially covered with an amorphous layer. By utilizing a diamond substrate on which a piezoelectric-substance thin film is formed, surface-acoustic wave devices having high propagation speeds can be offered.