High performance lithium niobate surface acoustic wave transducers in the 4-12 GHz super high frequency range

Surface acoustic wave (SAW) transducers are a well-established component used in numerous sensors, communications, and electronics devices. In this work, the authors report a systematic study of 320-800 nm period lithium niobate SAW interdigitated transducers (IDTs) corresponding to resonant frequencies in the 4-12 GHz range. An optimized SAW design and a nanofabrication process flow were developed, which enabled superior device performance in terms of frequency, signal losses, and electromagnetic coupling. The influence of the device alignment on the substrate crystal planes, in addition to the IDT period and electrode design, is found to have a significant impact on various process metrics. As an example, two identical SAW transducers fabricated perpendicular to each other may have a resonant frequency difference approaching 1 GHz, for the same harmonic mode. These and other trends are presented and discussed. (C) 2015 American Vacuum Society.