Thermo-acoustic engineering of silicon microresonators via evanescent waves
Abstract
A temperature-compensated silicon micromechanical resonator with a quadratic temperature characteristic is realized by acoustic engineering. Energy-trapped resonance modes are synthesized by acoustic coupling of propagating and evanescent extensional waves in waveguides with rectangular cross section. Highly different temperature sensitivity of propagating and evanescent waves is used to engineer the linear temperature coefficient of frequency. The resulted quadratic temperature characteristic has a well-defined turn-over temperature that can be tailored by relative energy distribution between propagating and evanescent acoustic fields. A 76 MHz prototype is implemented in single crystal silicon. Two high quality factor and closely spaced resonance modes, created from efficient energy trapping of extensional waves, are excited through thin aluminum nitride film. Having different evanescent wave constituents and energy distribution across the device, these modes show different turn over points of 67 °C and 87 °C for their quadratic temperature characteristic.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 29, 2015
- Source ID
- 10.1063/1.4923056
Entities
People
- Farrokh Ayazi
- Roozbeh Tabrizian
Organizations
- Defense Advanced Research Projects Agency
- Georgia Tech
- University of Michigan