Fabrication and test of an electromagnetic vibrating ring gyroscope based on SOI wafer

Mode matching is the key to improve the performance of micro-machined vibrating ring gyroscopes. Mass and stiffness asymmetries can lend to normal modes badly mismatch for gyroscopes fabricated by single-crystal silicon. The mismatch of the normal nodes results in large normal mode frequency split and degraded sensitivity. To address this issue, a Silicon-On-Insulator (SOI) wafer is used to fabricate the sensor chips. Meanwhile, a compensate disk and the backside coated negative photo resist (AZ303) is employed to weaken the Lag and Footing effect during the Deep Reactive Ion Etching (DRIE) process. Test results reveal that frequency split between the normal modes is of less than 10 Hz before the following electronic tuning. Thus, the mode matching of the electromagnetic vibrating ring gyroscope is probable to be realized.