Design and Simulation of Novel MEMS based Capacitive Microphone

Lourembam Bandana, V. S. Selvakumar

Abstract: Nowadays, MEMS (Micro-electromechanical Systems) technology is widely used to design various types of microphone. The capacitive microphone is highly preferable because of its high achievable, sensitivity, miniature size, batch fabrication, integration feasibility and long stability performance. In this paper, a novel MEMS capacitive microphone operating at a low actuating voltage is presented. It consists of Aluminum diaphragm arranged over the rigid Silicon back plate in which the diaphragm includes a number of holes to reduce the acoustical damping as well as stiffness. The design and simulation has been done using the three modules of Intellisuite- Intellimask, 3D builder and TEM (Thermo-electromechanical) analysis. Comparing the diaphragm of two different thicknesses, the thinner one gives higher deflection under the same applied pressure. The variation in the capacitance with the increase in pressure is analysed. The simulated result shows that the pull-in Voltage is 0.3V and the zero bias capacitance is 5.09 Pf. A process flow for the fabrication is designed and simulated using Intellifab.

Keywords: MEMS, microphone, TEM, Pull-In voltage, Intellifab