[17p-D505-1~11] 1.6 Ultrasonics

△ [17p-D505-5] New method for extracting effective electromechanical coupling coefficient k_eff² directly from high overtone bulk acoustic resonator including electrodes

〇Yohkoh Shimano^1,2, Kohei Yatabe³, Takahiko Yanagitani^1,2,4,5,6 (1.Waseda Univ., 2.ZAIKEN, 3.Tokyo Univ. of Agri. and Tech., 4.JST-CREST, 5.JST-FOREST, 6.JST-START)

Keywords:Piezoelectric thin film, BAW devices, Electromechanical coupling coefficient

Electromechanical coupling coefficient is an important index that determines the bandwidth and insertion loss of RF filters. In high overtone acoustic wave resonator (HBAR), the effective electromechanical coupling coefficient k_eff² including electrode has not yet been directly evaluated. In general, k_eff² is measured using the resonance anti-resonance method (IEEE standard) after the piezoelectric layer is deposited on the substrate and the substrate is removed to form a freestanding bulk acoustic resonator (FBAR). In this report, we propose a new method for extracting k_eff² directly from HBAR including electrodes