Design and Fabrication of S<sub>0</sub> Lamb-Wave Thin-Film Lithium Niobate Micromechanical Resonators

Abstract

Commercial markets desire integrated multifrequency band-select duplexer and diplexer filters with a wide fractional bandwidth and steep roll-off to satisfy the ever-increasing demand for spectrum. In this paper, we discuss the fabrication and design of lithium niobate (LN) thin-film S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> Lamb-wave resonators on a piezoelectric-on-piezoelectric platform. Filters using these resonators have the potential to fulfill all the above requirements. In particular, we demonstrated one-port high-order S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> Lamb-wave resonators with resonant frequencies from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 400$ </tex-math></inline-formula> MHz to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 1$ </tex-math></inline-formula> GHz on a black rotated y-136 cut LN thin film. The effective electromechanical coupling factor ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$k_{eff}^{2}$ </tex-math></inline-formula> ) ranges from 7% to 12%, while the measured quality factor ranges from 600 to 3300. The highest <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$k_{eff}^{2} \times Q$ </tex-math></inline-formula> achieved on this chip is 194, significantly surpassing contour mode resonators manufactured in other technologies. [2014-0280]