Performance Optimization of Thin Film Micro-Patterned Piezoresistive Low Pressure Sensor

An array of micro-structured piezoresistive pressure sensors often becomes suitable for low-pressure environmental applications. In this work, we studied two different thin film arrays of triangular and pentagonal structures with different piezoresistive materials and structural configurations. Sensor parameters, such as Von Mises stress, resistance variation and linearity, etc., were evaluated using finite element method. The 0.5 µm height of the triangular structure achieves a higher sensitivity of 10.52 and thus shows the improved design of MEMS (Micro Electro Mechanical System) based piezoresistive pressure sensor. Different piezoresistor configurations also simulated using COMSOL Multiphysics software to obtain the optimal sensing outputs. We observed the best variation in resistance with the triangular and pentagonal array structures having a low-pressure range of 1 Pa to 10 Pa. The maximum deformation of 0.064 µm and 0.052 µm are also determined for both triangular and pentagonal array structures of 0.5 µm in height, respectively. The simulation results show that proper selection of the piezoresistor geometrical structure, shape, and dimensions allows possibilities to improve the sensor sensitivity for low-pressure applications.