Characterization of the SAW propagation properties for zinc oxide films on silicon carbide

The surface acoustic wave (SAW) propagation properties of zinc oxide (ZnO) films on silicon carbide (SiC) have been initially characterized using interdigital transducer (IDT) structures in four configurations. The dc triode sputtered ZnO films were 400 nm in thickness and the interdigital electrodes were processed on the film surface and at the film/substrate interface with and without a thin shorting metal at the opposite boundary of the ZnO film. The measurements characterized the velocity, propagation loss, and transducer conversion loss of the SAW modes. A generalized SAW mode with velocities between 6000 and 7000 m/s were observed as well as a strong high velocity pseudo-SAW mode with velocities in the 12 000 to 13 000 m/s region. The propagation loss for both modes was 10 dB/cm at 600 MHz and followed a frequency squared loss characteristic