Overload Capability Design of MEMS Polycrystalline Silicon Nano-Diaphragm Pressure Sensors

The pressure-sensing diaphragms of micro-electromechanical systems (MEMS) pressure sensors are prone to fracture under high pressure and eventually result in sensor performance failure. To address this issue, a technique is proposed in this study that can improve the overload capacity of MEMS polycrystalline silicon nano-diaphragm pressure sensors. A polycrystalline silicon diaphragm with a thickness of 80 nm is utilized for constructing the pressure-sensing diaphragm structure. Furthermore, the cavity height of the membrane for bottoming protection is analyzed using the static large deformation and contact nonlinear finite element analysis methods. Accordingly, the association of diaphragm sizes with sensor overload capacity is deduced, and the influence of diaphragm size variation on the overload capacity under different sensor ranges is discussed. The simulation results reveal that the MEMS polycrystalline silicon nanomembrane pressure sensor designed for a 1 MPa range exhibits an overload capacity of 8 MPa, which is eight times the sensor range. This study provides novel ideas that can contribute to the preparation of MEMS pressure sensors in real-time production.