Unprecedented figure of merit in excess of 108 in 920 MHz aluminum nitride cross-sectional Lamé mode resonators showing KT2 in excess of 6.2%

Abstract

In this work we demonstrate a 900 MHz cross-sectional Lamé-mode resonator showing a kt2 in excess of 6.2% and a loaded quality factor in excess of 1750. Such a high kt2, which closely matches that Finite-Element-Methods (FEM) predicted value, is attained through the use of a 3-finger CLMR and a thickness-field-excitation (TFE) scheme. This device not only shows a high kt2 comparable to the one attained by film-bulk-acoustic resonators, FBARs, but is also characterized by an unprecedented figure-of-merit (FoM108) that, to the best of the authors’ knowledge, is the highest demonstrated in AlN resonators operating at ~1 GHz.