Microscale three-dimensional hemispherical shell resonators fabricated from metallic glass

A novel use of bulk metallic glasses in microresonator applications is reported and a method for the fabrication of ultra-smooth and highly symmetric three-dimensional wineglass structures with integrated electrode structures is presented. A shell with N=2 modes at 9.393 kHz and 9.401 kHz was characterized for both mounted and unmounted (to the electrode structure) conditions. Prior to mounting, the resonator was found to have quality factors of 7800 and 6500 for the two degenerate modes. After mounting, capacitive readout of the shell structure in both the time and frequency domain showed the resonances shifted to 9.461 kHz and 9.483 kHz respectively, for the N=2 modes increasing the frequency split by 15 Hz. The quality factor was also found to be reduced with values of 5400 and 5300 respectively. This investigation demonstrates that a device such as the one reported here promises robust platforms for complete MEMS inertial sensors with low cost and simplified fabrication.