High-electromechanical-coupling-coefficient and High-velocity Surface Acoustic Wave Materials of ZnO Films on Diamond

Abstract

Functional coatings are effective for improving the properties of devices. The development of thin-film-based surface acoustic wave (SAW) devices coated with piezoelectric zinc oxide (ZnO) thin films has attracted considerable attention. The orientation and thickness of piezoelectric films will affect the characteristics of SAW devices. In this research, (100) ZnO films were combined with diamond to form new composite SAW substrates. The SAW properties of (100) ZnO films on diamond with four composite structures, namely, interdigital transducer (IDT)/(100)ZnO/diamond, (100)ZnO/IDT/diamond, IDT/(100)ZnO/metal/diamond, and metal/ (100)ZnO/IDT/diamond were systematically analyzed and some excellent SAW properties were observed. In particular, for mode 1 of (100)ZnO/IDT/diamond, a maximum K 2 of 5.85% and a maximum velocity of 8857 m/s were obtained at a minimum film thickness ratio of h/λ = 0.11. Such research results provide a predictable theoretical basis for the further application of such substrates in high-velocity SAW devices.

Improving the acousto‐optical interaction by an introduction of a planarisation SiO 2 layer

“…The hybrid integration of additional materials is a potential promising method to solve the non-piezoelectric effect of silicon for higher integration and flexible design of AO device [14,18,19]. Some researchers introduce a piezoelectric material into the surface of SOI wafer for the generation and propagation of SAW on SOI optical waveguides [14,[18][19][20]. The IDTs are located on the surface of the piezoelectric film to generate SAW.…”

“…The IDTs are located on the surface of the piezoelectric film to generate SAW. The ZnO is the general piezoelectric material due to good piezoelectric properties and high electro-mechanical coupling coefficient [20,21].…”