[20p-B103-1~19] 6.1 Ferroelectric thin films

△ [20p-B103-12] Comparison of the k_t² extraction methods of piezoelectric film/substrate structure and self-standing film structure

〇Ryo Seki^1,2, Shimizu Yuki^1,2, Yanagitani Takahiko^1,2,3,4 (1.Waseda Univ., 2.ZAIKEN, 3.JST-CREST, 4.JST-FOREST)

Keywords:piezoelectric film

Electromechanical coupling coefficient k_t² is an important factor for evaluating the performance of BAW devices. The resonance-antiresonance method, which is standard for k_t² evaluation, needs self-standing film structure (FBAR). On the other hand, we previously proposed various k_t² extraction methods without removing the substrate such as resonant frequency ratio method, conversion loss (CL) method with electromagnetic signal and CL method with subtracting acoustic losses. In this study, we compared seven k_t² extraction methods at same location on same ScAlN films.