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Temperature Characteristics of ScAlN/SiO2 BAW Resonators

MetadataDetails
Publication Date2018-10-01
AuthorsHonoka Igeta, Makoto Totsuka, Masashi Suzuki, Takahiko Yanagitani
InstitutionsWaseda University
Citations8

The electromechanical coupling coefficient $k_{\text{t}}^{2}$ , TCF and Qm factor of the stack structure of ScAlN/SiO2 or ScAlN/diamond BAW film resonators were simulated to compare with conventional single layer AlN films. $k_{\text{t}}^{2}$ of AlN films is not enough for BAW RF filter applications. ScAlN films have $k_{\text{t}}^{2}$ exceeding AlN films, but $\text{Q}{\text{m}}$ factor deteriorate with Sc doping. We experimentally investigated TCF of SC x A1 1-x N films with various Sc concentration. By using the experiment TCF, Simulated results shows that ScAlN/SiO2 BAW film resonators obtain higher $k{\text{t}^{2}}$ than one of AlN with good TCF. The Qm factor and TCF of ScAlN/diamond BAW film resonators were improved, whereas the $k_{\text{t}}^{2}$ was seriously decreased compared with single layer AlN. Therefore, the ScAIN/SiO2 BAW film resonators may be promising combination for BAW RF filter applications.