Design, fabrication and vapor characterization of a microfabricated flexural plate resonator sensor and application to integrated sensor arrays

Abstract

A chemical vapor detection and biosensor array based on microfabricated silicon resonators coated with thin film polymer sorption layers is described. The resonators within the array are micro-electromechanical (MEM) flexural plate wave (FPW) sensors that have been miniaturized to allow many independently addressable sensors to be integrated within a single silicon chip. The target analyte of an individual sensor within the chip is selected by placing a polymer coating onto the resonating membrane. Detection is performed by monitoring changes in the frequency and damping factor of the resonance as the coating interacts with the environment. This work documents vapor response characterization of an individual sensor element within an array and reports on the operation of an eight-element sensor array. Polymer coatings targeted toward detection of chemical weapon agents have been applied to the sensor and chemical vapor exposure tests using two chemical weapon simulants and four vapor phase interferents have been performed. Data describing temperature dependence, long-term/short-term drift stability, detection limits, detection linearity and vapor selectivity will be presented. The use of resonant damping information is shown to provide the ability to discriminate between vapor analytes that produce equal resonant frequency shifts.