SUBJECT: Ph.D. Proposal Presentation
BY: Peng Shao
TIME: Wednesday, November 13, 2013, 11:00 a.m.
PLACE: Van Leer Building, 218
TITLE: Microscale Hemispherical Shell Resonator Gyroscopes
COMMITTEE: Dr. Farrokh Ayazi, Co-Chair (ECE)
Dr. Olivier Pierron, Co-Chair (ME)
Dr. Peter Hesketh (ME)
Dr. Levent Degertekin (ME/ECE)
Dr. Oliver Brand (ECE)


Hemispherical resonator gyroscope (HRG) is one of the most successful designs for navigation grade gyroscope, which has been widely used in high value space missions. The physical principle of the HRG is based on the inertial properties of elastic waves propagating in a solid object. The undisputable advantage of these existing instruments is their high sensitivity, environmental stability, and robust operation over time. A disadvantage is their extremely high cost and large size. With the latest advances in micro-fabrication technology and the development of MEMS inertial sensors, there is a possibility that the conversional HRG can be miniaturized down to chip scale. This work explores the design, fabrication and testing of microscale hemispherical shell resonators (µHSR) and hemispherical resonator gyroscopes (µHRG). Free-standing three-dimensional
hemispherical shells are fabricated in single crystal silicon substrate. Their resonance characteristics are firstly measured by integrating electrode pillars around the hemispherical shells using a wafer assembly approach. This platform gives the possibility of studying the quality factor and frequency mismatch of an axial symmetric hemispherical shell resonator. The results demonstrate a highly symmetric and high Q hemispherical shell structure that is promising for a high performance µHRG. To create a µHRG, a monolithic process flow with co-fabricated and self-aligned polysilicon electrodes around hemispherical shell structure is developed. This 3D manufacturing technology combines the high aspect ratio trench-refill process and high aspect ratio hemispherical shell process. New fabrication technique is also developed for lithography with a three dimensional hemisphere surface topography.