Electrothermally actuated resonant rate gyroscope fabricated using the MetalMUMPs

This paper presents an electrothermally actuated resonant microgyroscope fabricated using commercially available standard MEMS process, MetalMUMPs. A Chevron-shaped thermal actuator has been used to drive the proof mass, whereas parallel plate electrodes have been used for sensing the rotation induced Coriolis force. The proposed model consists of three coupled proof masses that are driven together using a frame. To achieve larger bandwidth and increased sensitivity, the microgyroscope is operated with a slight mismatch in the resonant frequencies of the drive and sense-mode. Modal analysis in IntelliSuite predicted the drive and sense-mode resonant frequency at 5.37 and 5.2 kHz, respectively. A brief theoretical description of the resonant microgyroscope and mechanical design considerations of the proposed model are also discussed. Prototype fabrication using MetalMUMPs has also been investigated in this study. Microsystem Analyzer MSA-400 has been used to test the prototype at atmospheric pressure. The resonant frequency of the fabricated device is measured to be 5.98 kHz for the sense-mode. A drive displacement of 4.2 μm peak-to-peak is achieved by the proof mass when the device is operated at 1.3 Vac applied at 2.99 kHz consuming a power of 0.36 W. The proposed device has a size of 1.8×2.0 mm2. The large voltage–stroke ratio and low damping of chevron-shaped thermal actuator compared to traditional comb drive may result in a high quality factor microgyroscope operating at atmospheric pressure.