Characteristics of c-axis oriented GeAlN films and applications to higher-order mode BAW resonators

Abstract AlN film bulk acoustic wave (BAW) resonators and filters that operate at frequencies above 5 GHz are required for 5G beyond communication applications. However, the power-handling capability, Q factor, electromechanical coupling in high-frequency BAW will be degraded as a result of significantly reduced thickness volume devices. Higher-order mode with polarity inverted (PI) multilayered films can high while maintaining In this study, we fabricated an eight-layered PI GeAlN/AlN resonator by alternately growing Al-polar layers N-polar GeAlN layers. The resonated 8th-order mode. was approximately thirteen times larger than single-layer operating same frequency range.