| To meet the stringent requirements for high precision, wide dynamic range, and rapid response under complex operating conditions in high-speed railway traction and braking systems, this study presents the design, fabrication, and multiphysics optimization of a high-performance piezoresistive pressure sensor chip. A comprehensive structural optimization framework was established by coupling solid mechanics, thermoelectric, and carrier transport physics, enabling a systematic investigation into the coupled influence of membrane thickness, piezoresistor placement, and doping concentration on device sensitivity, linearity, and mechanical robustness. A stiffness-to-sensitivity co-optimization strategy was proposed based on a parametric design methodology. Furthermore, a customized eight-mask photolithography process and KOH/IPA hybrid anisotropic wet etching technique were developed, achieving submicron-level precision in suspended diaphragm thickness control. Finite element simulation results demonstrate a sensitivity of 56.987?mV/kPa, a nonlinearity of 0.048% FS, and structural stability under 300% overpressure. This work addresses a key technological bottleneck in high-accuracy MEMS pressure sensor fabrication and lays the foundation for fully localized production of safety-critical sensing components in next-generation traction systems for high-speed rail. |
