Special MEMS Industry Invited Lecture | High-Performance Fused-Silica Vibratory Micro Shell Resonator Gyroscope

Featuring Jae Yoong Cho, CEO of Enertia Microsystems

Abstract: Enertia Micro is commercializing a novel high-precision MEMS gyroscope technology called the birdbath resonator gyroscope (BRG) for rapidly emerging applications requiring excellent performance, small size, low power, and low cost (e.g. autonomous vehicles, industrial robots, consumer electronics, and aerospace applications).  The BRG is the world’s first fused-silica vibratory MEMS gyroscope and is a near-navigation-grade MEMS gyroscope (i.e. in-run bias stability < 0.01 deg/hr).  Fused silica is a very attractive material due to very low thermoelastic damping (TED) (10-100x lower than silicon at frequency < 100 kHz).  At U. Michigan, I invented a novel fused-silica high-temperature reflowing process to produce three-dimensional birdbath (i.e. half-toroidal) fused-silica shell resonators with mechanical quality factor (Q) of ~10 million at a frequency of 6-13 kHz and excellent mechanical uniformity.  The BRG with a 10-mm micro birdbath resonator (i.e. BRG10 or Precision Shell Integrating Gyroscope) demonstrated a Q of 5.2 million, decay time constant of 296 seconds, an angle random walk of 0.00016 deg/sqrt(hr), and an in-run bias stability of 0.0014 deg/hr, which is the best-reported performance from MEMS gyroscopes to date [Cho20].

[Cho20] Cho et al., "0.00016 deg/sqrt(hr) Angle Random Walk (ARW) and 0.0014 deg/hr Bias Instability (BI) from a 5.2M-Q and 1-cm Precision Shell Integrating (PSI) Gyroscope", IEEE Inertial 2020.

Bio: Jae Yoong Cho is the CEO of Enertia Microsystems Inc. (San Leandro, CA).  He received a Ph.D. degree in Electrical Engineering from the University of Michigan in 2012 (Advisor: Khalil Najafi).  He was a postdoc (2012-2015) and an assistant research scientist (2015-2020) at the University of Michigan.  In 2017, he co-founded Enertia Micro to commercialize the birdbath resonator gyroscope (BRG) technology, which he invented under the support of DARPA.  His expertise includes design, fabrication, and control of high-performance MEMS inertial sensors.