Analysing the Effects of Temperature and Doping Concentration in Silicon Based MEMS Piezoresistive Pressure Sensor

Wide range of improvements in the silicon integrated circuits and micromachining technology enables the development of various sensing instruments. Micro Electro Mechanical System (MEMS) technology enables fabrication of micromachined components and batch fabrication through Very Large Scale Integrated (VLSI) processing. In MEMS piezoresistive pressure sensor, temperature can be considered as the main environmental condition which affects the system performance. In this work, a study on the effects of temperature and doping concentration in a boron implanted piezoresistor for a high sensitive silicon based MEMS piezoresistive pressure sensor is discussed. Using the fundamental semiconductor equations, the dependance of conductivity and hence the resistivity of a piezoresistor on operating temperature and impurity doping concentration is analysed. It is also being observed that in physical environment, the effect of stress on the performance of MEMS pressure sensor will be more compared with the temperature and for a given pressure output voltage varies in a linear manner. FEA simulation tool CoventorWare® has been used for the simulation.