Chemical Application of Silicon-Based Resonant Microsensor

The detection of volatile organic compounds in liquid is of interest for applications in public health, workplace safety and environmental monitoring. Traditionally, water samples were taken and analyzed in the laboratory using classical laboratory instrumentation. Current trends target real-time measurements using e.g. chemical microsensors built with microfabrication technologies. Among these, mass-sensitive chemical sensors, based on cantilever beams or surface acoustic devices, have shown substantial promise in gas-phase applications. In a liquid environment, the resonant microstructures typically suffer from high damping, which negatively affects the sensor resolution. In this work, a novel disk-type resonator developed at Georgia Tech was investigated as chemical microsensor for liquid-phase applications. The micromachined resonator vibrates in a rotational in-plane mode shape, reducing damping in a liquid environment. As part of the present research, a measurement setup with a custom-made flow cell for liquid-phase chemical measurements and a coating system to locally deposit polymer sensitive films onto the resonators were developed. To improve the film adhesion on the resonator surface in liquid, physical and chemical binding techniques were developed and tested on wafer samples. Polymers such as poly(4-vinylpyrrolidone), poly(ethylene-co-propylene) and poly(styrene-co-butadiene) were deposited using the custom-designed coating system onto the disk-type resonators. Liquid-phase measurements using tetrachloroethylene as the chemical analyte were performed. The experimental results are discussed, sources of problems are identified and recommendations for future research are made.

Department dc:contributor.department

Electrical and Computer Engineering

Grantor dc:publisher

Georgia Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Byun, Albert Joonsoo

Advisor dc:contributor.advisor

• Brand, Oliver

Committee members dc:contributor.committeemember

• Frazier, Bruno
• Mizaikoff, Boris

• Chemical sensors
• MEMS
• Mass-sensitive
• Resonator
• Liquid measurement
• Polymer coating
• Flow cell
• Disk-type resonator

Handle dc:identifier.uri

http://hdl.handle.net/1853/16296

OAI identifier oai:identifier

oai:repository.gatech.edu:1853/16296