High Sensitivity CMOS Pressure Sensor Using Ring Channel Shaped MOSFET Embedded Sensing

This paper examines the modeling and simulation of a CMOS-MEMS integrated pressure sensor using ring channel shaped MOSFET embedded sensing technique. A resistive loaded n-channel MOSFET based current mirror pressure sensing readout circuitry has been designed using standard 5 mu m CMOS technology. Two structures consisting of a square and a circular ring channel shaped MOSFET embedded on a square and a circular silicon diaphragm, respectively, have been investigated. Piezoresistive effect in MOSFET has been exploited for the calculation of strain induced mobility change under externally applied pressure. Finite element method based COMSOL Multiphysics is utilized for the simulation of pressure sensor. TSpice is employed to evaluate the characteristics of the current mirror pressure sensing circuitry. Simulation results show that the sensitivities of the pressure sensor utilizing the square and the circular diaphragms are approximately 406.88 and 657.91 mV/MPa, respectively. In addition, the non-linearity in the deflection of the square and circular diaphragms as a function of applied pressure has also been investigated. These ring channel shaped MOSFET embedded pressure sensors have a promising application in the design and development of smart sensors for biomedical applications.