Design and Simulation of MEMS Capacitive Pressure Sensor B. B. Kirankumar, Vinay Shettar, Sneha B. Kotin and B. G. Sheeparamatti 1 Dept. of ECE, Basaveshwar Engineering College, Bagalkot 587 103. e-mail: kiran4004@gmail.com, vinay.shettar56@gmail.com, snehabk050@gmail.com, sheepar@yahoo.com Abstract. Employing the MEMS technology, high sensitivities and resolutions have been achieved. Capacitive sensing uses the diaphragm deformation-induced capacitance change. In this paper, the design and simulation of conventional slotted and touch mode MEMS capacitive pressure sensor is proposed. The designed sensors are composed of a polysilicon diaphragm that deflects due to pressure applied over it, is accounted for modeling. The simulation results shows that the slotted MEMS capacitive pressure sensor achieves good sensitivity where as the touch mode MEMS capacitive pressure sensor achieves good linearity and large operating pressure range. The proposed MEMS capacitive pressure sensor demonstrated with diaphragm of side length 20 μm, gap depth 2 m is being modelled. The sensor exhibit a linear response for the pressure applied between 0 to 50 MPa. The simulation is carried out for different types of MEMS capacitive pressure sensor using COMSOL Multiphysics. Keywords: MEMS, Capacitive pressure sensor, Touch mode pressure sensor, Slotted diaphragm, COMSOL multiphysics. 1. Introduction MEMS (Micro-Electromechanical Systems)are of small size, light weight, enhanced performance and reliable systems. A typical MEMS Sensor is at least one order of magnitude smaller than the traditional sensors used to measure instantaneous flow quantities. MEMS pressure sensors measure the pressure in term of deflection of sensing plate. Micro Electro Mechanical Systems (MEMS) [1] are the integration of mechanical elements, sensors, actuators and electronics on a common substrate using integrated circuit process sequences. Sensors are the devices used to provide information on the presence or absence of an object and they convert a signal into a readable output. Pressure sensors are the devices that read changes in pressure. MEMS based pressure sensors [2] are mechanically similar to traditional sensors with the exception that these are Silicon based and on micrometer scale. Micro pressure sensors are widely applied in automotive, biomedical, space, military and various industrial applications. Pressure sensors fabricated by MEMS technology have the benefits of small size, low cost and high performance [3]. Capacitive pressure sensors provide very high pressure sensitivity, low noise and low temperature sensitivity and preferred in many high performance applications. Capacitive pressure sensors rely upon the applied pressure altering the distance between the two electrodes resulting in a change in the capacitance. Typically, the position of one electrode is fixed while the second electrode moves relative to it. Nowadays, it has become common for scientist and engineers working in micro-electro mechanical system (MEMS) area to simulate the structures using MEMS simulation software like COMSOL Multiphysics [4] before actual fabrication. COMSOL Multiphysics software is used for simulation of MEMS capacitive pressure sensor to optimize the design, improve the performance and reduce the time of fabrication process of the device. The objectives of analysis are first, to verify the deflection of the diaphragm due to the applied pressure between the diaphragm and the substrate. Second, to verify the deflection and capacitance between the diaphragm and the substrate The main intension in using this software is to optimize the structure dimensions to get the required output which saves time and money during fabrication. 2. Literature Survey Capacitive pressure sensor uses the diaphragm deformation-induced capacitance change. The advantages of a touch mode pressure sensor, the robust structure is to make the sensor to withstand harsh environment, near linear output, © Elsevier Publications 2014. 777