Novel MEMS Piezoresistive Sensor Array Cell

The future of analytical methods based on micro-fabricated cantilever sensors is critically sensitive to parallel processing: some because of the increased throughput required, but others, because of the complexity of the value to analyze. Parallel functioning needs arrays with cantilevers having two additional properties, simultaneously: to be addressable and to be independently actuated. Fulfilling these two requirements together, causes substantial increasing of complexity of both: layout and manufacturing technology. In present paper we demonstrate a novel design of MEMS-cell solving upper dilemma. The cell consists of four integrated cantilevers, having a single piezo-resistor each and different resonance frequencies. Samples of e-NOSE piezoresistive sensor using micro cantilevers on n-type, <100> Silicon, have been fabricated applying combined dry and wet etching techniques. The cantilever dimensions were chosen to provide approx. 1.5 kHz resonance frequency gap between any two neighbor sensors. The integrated bimorph actuator is common for all four of them, which fit very well a particular application. The behavior of the new cell was studied and its optimization according to both: manufacturing technology and application criteria was discussed.