New electrostatically excited Silicon resonator vibrating in a thickness extensional mode

Sylvain Ballandras , Mihaela Evan , Bernard Dulmet , Gilles Martin (1) , Thomas Baron

1 FEMTO-ST - Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174)

This paper presents a new micro-mechanical BAW resonator built in Silicon, using an electrostatic excitation. The device is based on a one-port design with a 1µm gap to apply the superimposition of static bias voltage and dynamic excitation to the silicon plate. A thickness extensional mode is exploited, yielding a frequency operation near 10 MHz with a standard 400µm thick Si plate. The resonator presented in the paper is based on a single p-doped (100) Silicon plate bonded onto a Corning® glass substrate by using the anodic bonding technique. The glass layer is machined to create the electrostatic gap mandatory for the electrical excitation. The micro-fabricated resonator was tested in one-port configuration using a network vector analyzer. The electromechanical coupling factor and many resonator features, including the quality factor Q, change with the DC bias polarisation, as expected theoretically. After the static capacitance compensating, the Q factor near 9000 have been observed with a promising coupling w.r.t. quartz resonator values. The resonator was tested in air at different temperatures between 0°C and 100°C and the TCF was found at -28ppm/°C. The stabilization of a RF oscillator using this resonator is still under development.

Mots clés: MEMS; silicon; RF; resonator

Domaines: Acoustique [physics.class-ph]

Sylvain Ballandras, Mihaela Evan, Bernard Dulmet, Gilles Martin, Thomas Baron. New electrostatically excited Silicon resonator vibrating in a thickness extensional mode. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00811246⟩