Thin-Film Lithium Niobate Acoustic Resonator with High Q of 237 and k<sup>2</sup> of 5.1% at 50.74 GHz
Jack Kramer, Vakhtang Chulukhadze, Kenny Huynh, Omar Barrera, Michael E. Liao, Sinwoo Cho, Lezli Matto, Mark S. Goorsky, Ruochen Lu
Abstract
Summary This work reports a 50.74 GHz lithium niobate (LiNbO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> ) acoustic resonator with a high quality factor (Q) of 237 and an electromechanical coupling (k <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) of 5.17% resulting in a figure of merit (FoM, Q•k <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) of 12.2. The LiNbO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> resonator employs a novel bilayer periodically poled piezoelectric film (P3F) 128º Y-cut LiNbO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> on amorphous silicon (a-Si) on sapphire stack to achieve low losses and high coupling at millimeter wave (mm-wave). The device also shows a Q of 159, k <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of 65.06%, and FoM of 103.4 for the 16.99 GHz tone. This result shows promising prospects of P3F LiNbO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> towards mm-wave front-end filters.