A novel bulk micromachined tunneling gyroscope

Abstract

A bulk micromachined vibratory tunneling gyroscope, which employs the high displacement sensitivity of quantum tunneling to obtain the desired resolution and is fabricated with silicon-glass wafer bonding and DRIE (Deep Reactive Ion Etching), has been developed. The device structure consists of a proof mass which can oscillate due to electrostatic comb driving and an out-of-plane silicon frame linked up to substrate by suspended springs. Because of adopting the silicon frame structure to get larger proof mass and putting tunneling tip at the end of silicon frame to obtain remarkable deformation induced by Coriolis force, the new ultracompact devices can provide extremely high sensitivity and wide dynamic range. Based on the modal analysis of gyroscope by FEM method, the structure dimensions are optimized according to resonant frequency matching of driving mode and detection mode. Simulation results demonstrate that the gyroscope owns the sensitivity of 0.7 A(°/sec) at atmospheric pressure. The deep dry silicon on glass (DDSOG) process has been successfully used to fabricate this bulk tunneling gyroscope. The tunneling current is observed at deflection voltage 45.7V. The exponential relationship between tunneling current and square deflection voltage verifies the tunneling effect mechanism between the tip and the detected electrode.