Design and optimization of a novel diaphragm structure for MEMS piezoresistive pressure sensors

MEMS piezoresistive pressure sensors are widely applied across diverse fields owing to their low cost, high accuracy, high reliability, and compact size. To address market demands for high-performance pressure sensors, a novel diaphragm structure for MEMS piezoresistive pressure sensors is proposed, optimized for the 0–5 kPa low-pressure range with high sensitivity and low nonlinearity. However, high sensitivity is typically achieved by increasing the diaphragm’s width-to-thickness ratio, which concurrently amplifies nonlinearity; consequently, a trade-off between sensitivity and low-pressure nonlinearity is necessitated in practical applications. The diaphragm structure was designated as the analysis subject, with small-deflection deformation treated as a nonlinear constraint. ANSYS finite element simulations were employed to investigate the effects of diaphragm width, thickness, and mechanical properties on sensor sensitivity and output voltage. Results demonstrate that diaphragm width is positively correlated with output voltage and sensitivity, whereas thickness exhibits a negative correlation; a sensitivity of 7.09 mV/V/kPa and nonlinearity of 0.204% FSS were attained, effectively resolving the sensitivity-nonlinearity trade-off in MEMS pressure sensors.