Raised-Frame BAW Resonators for Low Lateral Energy Leakage

The device is segmented into distinct functional regions: an active region for acoustic wave generation and a raised frame region for acoustic confinement. This segmentation allows the raised frame structure to independently address lateral energy leakage without interfering with the core resonator function, thereby improving quality factor while maintaining clear functional separation.

A raised frame structure composed of low acoustic impedance material (such as silicon dioxide) is introduced as an intermediary element between the active region and the substrate. This intermediary structure acts as an acoustic barrier that reduces lateral energy leakage into the substrate, thereby improving the quality factor without requiring fundamental changes to the resonator design.

The raised frame structure is positioned at specific locations outside the carrier aggregation bands where spurious modes typically occur. By locally addressing these problematic frequency regions rather than attempting global frequency tuning, the structure minimizes insertion loss at critical operating frequencies while maintaining adaptability for different carrier aggregation configurations.

The acoustic impedance parameters of the raised frame structure are specifically optimized to create acoustic barriers at frequencies outside the carrier aggregation bands. By controlling the impedance contrast between the raised frame material and the surrounding structures, the design suppresses spurious modes and reduces insertion loss while allowing the resonator to operate across desired frequency ranges.