Solidly Mounted Anti-Symmetric Lamb-Wave Delay Lines as an Alternate to SAW Devices

This letter reports the first results on a new generation of anti-symmetric lamb-wave devices using a simple solidly mounted platform of AlN/Mo/Si and operating at very-high-to-super-high frequency range. AlN/Mo/Si-based solidly mounted resonators (SMRs) with sub-micrometer interdigitated transducers were fabricated using the electron beam lithography and liftoff process. Plasma etching was used to etch vias in ground pads to get access to the bottom electrode for grounding. By comparing the floating, grounded, and no bottom electrode device performances, it has been observed that the presented SMR design with grounded bottom electrode results in enhancement of the coupling efficiency by 500% compared with conventional SAW devices. In addition, these devices are more mechanically robust and can be monolithically integrated with a CMOS platform without requiring complex packaging processes compared with conventional released lamb-wave resonators.