Material Selection and Performance Analysis of Organic MEMS Cantilever Force Sensors with Integrated Piezoresistive Readout

In this work, we investigate the performance of micro-electro-mechanical systems (MEMS) technology based organic cantilever force sensors with integrated piezoresistive readout. The study has been carried out in two phases: Phase-I involves material selection of both the organic cantilever platform and the piezoresistor to maximize the electrical sensitivity of the sensor. Here, the piezoresistor Gauge factor (G) to Young’s modulus (Y) of the cantilever platform material ratio (G/E) is considered as the performance evaluation metric. Subsequently, in phase-II, for the chosen material set, numerical investigation is carried out. Finite element method (FEM) based computer aided design (CAD) software is utilized for numerical simulations. Here, we compare two different organic materials (paper and Polydimethylsiloxane- PDMS) based sensors using simulation software. For comparison of cantilever force sensor performance realized with paper and PDMS, for both cases, we have considered the same cantilever shape, i.e. triangular with constant area (1200 µm²). Simulations were carried out, to investigate the electro-mechanical response of the sensors. From simulation results, it is found that for the same area and external applied force, the combination of Graphite piezoresistor and PDMS substrate depicts relatively higher mechanical sensitivity and electrical sensitivity than its counterpart sensor.