Effect of annealing on mechanical quality factor of fused quartz hemispherical resonator

This paper reports the experimental demonstration of Quality factor (Q-factor) improvement of fused quartz hemispherical resonators after post-fabrication annealing. Several identical fused quartz 3D hemispherical resonators, thickness 1 mm and diameter 10 mm were fabricated using micro-glassblowing process and tested before and after annealing. Results showed that annealing at 800 °C for 6 hours followed by slow overnight cooling significantly improved Q-factor, from 666×103 to 932×103 in our experiments. The annealing dependence was investigated by varying temperature from 500 °C to 800 °C. Change in Q-factor was observed to be minimal (<;10%), when annealed at 500 °C, for both n=2 and n=3 wineglass modes. Q-factor changes were ~40% when annealed at 800 °C. The experimental result on Q-factor enhancement is valuable for the development of very high Q fused quartz vibratory MEMS resonators for use in precision inertial sensing.