Investigating the effect of diaphragm cut pattern on overall sensitivity and pressure range of piezoresistive pressure sensor

This study proposes a comprehensive finite element analysis (FEA) of an architected piezoresistive pressure sensor for micro-electromechanical systems (MEMS), focusing on the effects of different diaphragm cut patterns to enhance sensitivity, linearity, and pressure range. Two designs are introduced: Design-1 with straight cuts and Design-2 with arc-shaped cuts. The investigation evaluates stress distribution, deflection, and output voltage across a Wheatstone bridge circuit under varying applied pressures. In Design-1, straight cuts near the diaphragm edges regulate stress distribution, channeling it across the piezoresistors and achieving an 80% increase in sensitivity compared to the baseline design, with a maximum sensitivity of 0.464 mV/V/kPa and nonlinearity error of 1.03%FSS. Parametric studies identify optimal cut dimensions to maximize sensitivity while ensuring linearity and compliance with small deflection theory. Design-2 incorporates arc-shaped cuts that redistribute stress away from the piezoresistors, extending the pressure range to 7 MPa with nonlinearity error of 0.12% (full-scale span) FSS. The strategic placement and geometries of these cuts enable precise control over stress distribution, allowing for tailored performance enhancements in sensitivity or pressure range to meet specific application requirements.