CMOS multi-terminal pressure sensor with on-chip biasing circuit

This paper describes the design, microfabrication and characterization of a 0.35 ¿m CMOS compatible multi-terminal pressure sensor (MTPS) with on-chip biasing circuit. This sensor is an alternative to the pressure sensors based on the conventional silicon Wheatstone piezoresistive bridge (WB) or four terminal piezotransducers. The layout of the MTPS is designed in such a way that the sensor sensitivity is effectively improved and the short-circuit effects, which are modeled by the geometrical correction factor (G), can be minimized. This multi-terminal topology maximizes the sensor sensitivity and minimizes the effect of the geometrical correction factor with the aspect ratio of the sensor. A polysilicon gate is also fabricated over the sensor´s active region to further enhance its sensitivity. The sensor design was supported by the finite element method (FEM). The MTPS sensitivity amounts to 0.24 mV/psi.