P5I-4 Diamond Saw Resonators With SiO2/ZnO/IDT/ZnO/Diamond Structure

Diamond surface acoustic wave (SAW) resonators based on a SiO₂/ZnO/diamond structure have been successfully developed to operate at a high frequency (ranging in GHz) and with good temperature stability. According to Lesson´s model, in order to obtain low phase noise the resonators in the oscillator circuit should have high power durability. This paper describes the improved power durability attained by diamond SAW resonators with an improved structure. The improved structure was achieved by adding one thin layer of ZnO film between the SiO₂ and IDT layers of the conventional structure. It was found that the resonator with the improved structure was capable of handling 20 more dB of input power than the conventional structure handles. Structural calculations performed using the finite element method (FEM) confirmed a dramatic improvement in durability without significant changes in characteristics compared to the conventional structure, which does not have a layer of ZnO over the IDT.