Simulation Thermomécanique de Capteurs de Pression au silicium Pour des Applications Biomédicales

Abstract

"This memoire aims to study the Thermo-Mechanical Behavior of Silicon Pressure Sensors for Biomedical Applications. Even though the main function of silicon pressure sensors stays the same for several years, the optimization of sensors for a given application still always puzzling step. The first chapter provides a general view of the silicon pressure sensors, in addition to the main function and the theoretical model of the capacitive and piezoresistive response. In the second chapter, a 3D model in COMSOL Multi-physics environment is established with an integral structure of the capacitive pressure sensor of the circular diaphragm form by using the Silicon/Pyrex technology. The simulation results show that the temperature sensitivity does not depend on the substrate thickness, but depends on the welding width, the thickness of the diaphragm, the thickness of the cavity and the form of the fixed support. The response of the piezoresistive silicon pressure sensor based on the pressure and the temperature and it is determined in the third chapter. Despite of their many advantages, high accuracy, low non linearity, the piezoresistive pressure sensors are extremely sensitive to temperature. A system for measuring plantar pressure is studied in the fourth chapter. The system is realized through coupling COMSOL Multiphysics and MATLAB-Simulink. This system presents the advantage the simplicity of the conception and the low cost in comparison with devices available in markets"