Ferroelectric-on-Si Super-High-Frequency Fin Bulk Acoustic Resonators With Hf0.5Zr0.5O2 Nanolaminated Transducers

This letter reports, for the first time, on the ferroelectric-on-semiconductor fin bulk acoustic resonators (FoS-FinBARs) with lithographically scaled frequencies up to 18 GHz and k _eff². Q as high as 17. The FoS-FinBARs benefit from the large electromechanical coupling of the ferroelectric hafnium zirconium oxide (Hf_0.5Zr_0.5O₂) nanolaminates created by atomic layering. The ferroelectric transducer is conformally deposited on silicon fins with sub-1- μm widths enabling excitation of super-high-frequency bulk acoustic wave resonance modes with increasing k _eff² at higher frequencies. FoS-FinBARs, created by a CMOS-compatible process, are presented with frequencies over 2-18 GHz, Qs exceeding 500, and k _eff²s as high as 4.7%.