A Bulk-Type High-Pressure MEMS Pressure Sensor With Dual-Cavity Induced Mechanical Amplification

A bulk-type, single-cavity, piezoresistive pressure sensor was previously developed and characterized up to 200 MPa. Its sensitivity of
$79~\mu \text{V}$
/V/MPa was limited by the bulging of the surface on which the piezoresistors were constructed. Presently reported is a bulk-type, dual-cavity pressure sensor with an improved construction and a new layout design of the piezoresistors. Simulation based on finite-element analysis has been used to study the dual-cavity induced stress amplification, and to guide the design of the thickness of the pressure sensing plate and the height of the cavities. Characterized over the same pressure range of 200 MPa, the dual-cavity sensor exhibits a ~2.5-times higher sensitivity of
$200~\mu \text{V}$
/V/MPa. Furthermore, compliant silicon pillar connectors have been incorporated in the sensor without requiring additional fabrication processes. Simulation has been performed to show the potential of a chip-scale packaging implementation capable of largely relieving packaging-induced stress. [2022-0019]