18-MHz Silicon Lame Mode Resonators With Corner and Central Anchor Architectures in a Dual-Wafer SOI Technology

This paper presents Lame bulk mode square resonators fabricated in a novel silicon-on-insulator technology, MicraGEM-Si. Structures are formed by patterning two wafers with several etched depths and wafer bonding them to create the released movable resonator structures. Two distinct anchoring architectures are studied: one with suspension beams at the nodal corner points, and the other with a central anchoring support. The center support architecture can be suitable for realizing high-performance gyroscopes. Resonators with different support sizes are fabricated and characterized. Fabricated devices were measured to operate at a resonance frequency of similar to 18 MHz and quality factors as high as similar to 42 000 in atmospheric pressure, which to the best of our knowledge is the highest reported to date at such an ambient pressure, and similar to 871 000 in 100-mtorr vacuum, corresponding to a f.Q product of similar to 1.6x1013.