3-D micromachined hemispherical shell resonators with integrated capacitive transducers

We present a self-aligned fabrication method developed for three-dimensional (3-D) microscale hemispherical shell resonators with integrated capacitive transducers and a center post for electrical access to the shell. The self-aligned process preserves the axisymmetry for robust, balanced resonators that can potentially reach very high-Q due to suppressed anchor loss. High-Q operation of a thin polycrystalline silicon shell resonator is verified by exciting devices capacitively into a breathing resonance mode, with measured Q of 8,000 at 412 kHz in vacuum. This process can be further optimized to batch-fabricate micro-hemispherical resonator gyroscopes for portable inertial navigation.