Abstract
We designed a SAW filter in this work by combining the piezoelectric ZnO film with a freestanding double layer diamond film deposited using CH~4~–H~2~ pulsed MPACVD process through two growth stages. The AFM measurements on the nucleation side of the diamond film has shown that this side is smooth enough to perform photolithography process in the SAW device elaboration, while the good quality of the diamond film produced on this side has been confirmed through Raman spectroscopy.
Furthermore, the ZnO films having their c axis perpendicular to the substrate were deposited using reactive magnetron sputtering under the optimal experimental conditions found from XRD measurements. In the SAW device elaboration on this ZnO/bilayer diamond structure, aluminium interdigital transducers (IDTs) were developed by conventional contact UV photolithography on the nucleation side of the freestanding diamond. The frequency response of the device presents harmonics of the acoustic wave modes propagating in the smooth diamond nucleation side. The good agreement obtained between the experimental and theoretical frequency responses attests that the elastic properties of the ZnO and the diamond are similar to those of the single crystal assumed in the theoretical study. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)