Fabrication and testing of hemispherical MEMS wineglass resonators

Abstract

This work focuses on understanding the behavior of 3D hemispherical shells operating in wineglass resonance mode through finite element modeling (FEM). Fabrication of the hemispherical shells was done using micromachining technique. The quality factor of the device was in excess of 10,000 when operated in 50mT vacuum. The shell showed better than 95% sphericity and had an rms surface roughness of ~5nm. The separation in the degenerate frequencies of 4-node wineglass resonance was 5 Hz at a resonant frequency of 22 kHz. Modeling of the device behavior relates the frequency mismatch to the asymmetry in the shell and quantifies it.