Robust MEMS Gyroscope Based on Thermal Principles

Two variants of a novel single-axis thermal gyroscope without seismic mass are designed, fabricated, and characterized in this paper. The operating principle of the device is differential temperature detection due to the Coriolis effect on an oscillatory gas stream created by alternating two resistive microheaters. The fabrication process is based on a bulk micromachining technology on a silicon substrate using platinum as the only conductor layer. The device structure consists of two resistive temperature detectors equally spaced from the two microheaters. The 170-nm-thick platinum heater and detector microstructures are freely suspended over a cavity etched into the substrate, with minimal structural support. A computer-controlled precision rotary stage is constructed to accurately measure the device performance. The devices demonstrate excellent linearity within the tested ±3.5 revolution per second angular rate of rotation and show sensitivities of 0.947 and 1.287 mV/ ^°/s at 20 mW heater powers. The robustness of the devices has been validated by the drop shocks of 2,722 to 16,398g (9.81 m/s²).