DESIGN AND FABRICATION OF A MICROCANTILEVER-BASED SENSOR FOR NERVE GAS DETECTION

Surface-micromachined MEMS processes were used to fabricate this gas sensor. We fabricated a variety of designs, including those with one end fixed, two ends fixed and four ends fixed. In addition to the first bending mode, the torsional mode is being used for sensing and actuation. The placement of air venting holes as well as the placement of the sensing and actuating electrodes have been varied in the designs. A custom polymer layer (PPE-1-LBS) that absorbs the nerve gas analog DMMP is applied to the surface of goldcoated microcantilevers. The polymer coating is applied just after the cantilever is released with hydrofluoric acid but before the drying process. This paper describes the important steps in the fabrication process and compares the manufacturability of the various cantilever designs. It also compares the expected performance of four types of designs.