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Abstract
Biological sensing in the mechanical domain offers novel opportunities to measure cellular processes. Operating mechanical resonators in liquid environment for the detection of mass presents a challenge at least for electrical characterization. In this paper, we demonstrate the full electrical characterization of a micromechanical resonator that is fully immersed in DI-water. The reported device uses piezoelectric transduction through an Aluminium Nitride (AlN) film sputtered on a low damping silicon substrate to provide strong electromechanical coupling. The effect of viscous damping in DI-water is lowered by exciting the resonator to vibrate in an in-plane contour mode. We believe that incorporating a 10 µm thicker silicon substrate layer stiffens the resonant system and thereby increases the energy storage capacity in relation to a resonator structured purely by a thin AlN film. The 14 MHz length extensional (LE) mode resonator presented in this paper shows a quality factor (Q) of 200 when fully immersed in DI-water, which is twice that of previously reported resonators structured purely in AlN. The associated motional resistance of the device in DI-water is 40 kΩ. We have also measured the values of Q for several other in-plane resonant modes with higher resonant frequencies (up to 141.69 MHz) when immersed in DI water. Having found that the high dielectric constant of DI-water significant affects the characterization setup, we have also modeled the various sources of parasitics involved in the setup.
Original language | English |
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Pages (from-to) | 216-223 |
Journal | Sensors and Actuators, A: Physical |
Volume | 241 |
Online published | 15 Feb 2016 |
DOIs | |
Publication status | Published - 15 Apr 2016 |
Funding
The work described in this paper was supported by a grant from the Research Grants Council of Hong Kong under project number CityU 11206414.
Research Keywords
- MEMS resonator
- Thin film piezoelectric-on-silicon
- Feedthrough capacitance
- Viscous damping
- CANTILEVER SENSORS
- CHEMICAL SENSORS
- BIOSENSORS
- MICROCANTILEVER
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Dive into the research topics of 'Electrical characterization of piezoelectric-on-silicon contour mode resonators fully immersed in liquid'. Together they form a unique fingerprint.Projects
- 1 Finished
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GRF: Exploiting Thickness Shear Mode Acoustic Resonance in Piezoelectric-on-Si Unreleased Micromechanical Resonators for Gravimetric Biosensing in Fluid-Damped Media
LEE, E.-Y. J. (Principal Investigator / Project Coordinator) & LAM, H. W. R. (Co-Investigator)
1/01/15 → 31/05/19
Project: Research