Micro Pressure Sensors of 50 μm Size Fabricated by a Standard CMOS Foundry and a Novel Post Process

This paper describes a piezoresistive micro pressure sensor with a size of 50μm made by a standard CMOS foundry and a novel post process. The material of the sensor diaphragm is silicon dioxide, and the piezoresistors are made by polysilicon. For releasing the diaphragms of the micro pressure sensors, this work proposes to use the front-side etching technique with etching holes of 5μm×5μm only. Finally, we use one of the protein stuffs, gelatin, to seal the etching holes. The sensitivity of the piezoresistive pressure sensor is 8.56±0.13 mV/V/psi.