Design and simulation of silicon and polymer based piezoelectric MEMS microphone

A microphone is a transducer that measures an acoustic pressure and generates an electrical output. MEMS microphones have the advantages such as compact size, high signal-to-noise ratio, high sensitivity, quick response, and long term stability. Depending on the transduction principle microphones are classified as capacitive, piezoresistive, piezoelectric, optical and micro flow. An electret condenser microphone (ECM) works on the principle of piezoelectricity. When an acoustic pressure is applied on a piezoelectric material, it vibrates and charges are accumulated on the surface of the piezoelectric material. In this paper first the stress analysis is carried out on the silicon membrane and also on SU-8 membrane in response to acoustic pressure. The location of maximum stress is determined. The analysis is repeated by depositing the PZT-5H patches in the tensile and compressive stress regions of both membranes. The simulations have been carried out using Structural Mechanics and Piezoelectric Devices (PZD)Physics in COMSOL Multiphysics.