Polymer-Based Micro/Nano Cantilever Electro-Mechanical Sensor Systems for Bio/Chemical Sensing Applications

In this chapter, we present the status of polymer cantilever sensor platforms for biochemical sensing and energy harvesting applications. We introduce a novel process flow for polymer microstructure fabrication called the SPARE MEMS, which involves Spinning of sacrificial/structural layers, Patterning, Anchor formation and the final RElease of the device stack along with the anchor from the substrate. In this process the wafer is spared and is reusable. An organic/thin film FET embedded cantilever devices (CantiFETs) have been demonstrated using this process in order to reduce the noise levels and to achieve high deflection sensitivities. We have also used the SPARE MEMS process to fabricate a variety of other piezoresistive polymer cantilever devices with the highest reported deflection sensitivity (>100 parts-per-million/nm) to surface stress. Electronic circuit design approaches for the detection of ΔR down to sub parts-per-million level of resolution for piezoresistive cantilevers are also discussed. Using various surface coatings, development of sensor systems and sensor nodes for the detection of nitro-based explosive compounds, cardiac proteins, and environmental sensors are demonstrated. For powering the sensors, a novel piezoelectric polymer composite platform has been proposed.