Induced-Stress Analysis of SU-8 Polymer Based Single Mass 3-Axis Piezoresistive MEMS Accelerometer

This paper presents the induced-stress analysis of an SU-8 polymer based 3-axis piezoresistive MEMS accelerometer having a single proof mass along with proposed fabrication process flow. Polymer accelerometers are simple to fabricate and have better sensitivity because of their lower Young's modulus. It is also easy to integrate any highly sensitive piezoresistive material as a layer to further enhance the performance. In this work, structural design and push-pull mechanism of the beam and its use to achieve the desired results have been explained. Using basic structural analysis, locations of the maximum induced stress are identified. For acceleration of 100 g and 1 g, the proposed design has been investigated for the stress field in the structure and shown the improvement by comparing the performance with two published design presented in the paper. The proposed fabrication process is compatible with several piezoresistive materials such as ZnO nanorods, graphene and carbon nanotubes (CNTs).