A novel x-axis tuning fork gyroscope with '8 vertical springs-proofmass' structure on (111) silicon

摘要

A novel x-axis tuning fork gyroscope with "8 vertical springs-proofmass" structure is presented. Wafer-thick proofmasses are made out of (111) silicon with bulk micromachining processes to achieve lower thermo-mechanical noise. Each proofmass is supported by 8 vertical springs, which are symmetrically distributed around the proofmass. The dimensions of 8 vertical springs are precisely confined by thermal oxide protected sidewalls and the extreme slowly etched (111)-planes in KOH etching. A mode mismatch of less than 30 Hz is achieved before tuning. Initial test shows a sensitivity of 0.15 mV/ (deg/s) and a rate resolution around 0.1 deg/s under atmosphere pressure.