MEMS Shielded Capacitive Pressure and Force Sensors with Excellent Thermal Stability and High Operating Temperature

Abstract

In this paper, we present an innovative manufacturing process for the production of capacitive pressure and force sensors with excellent thermal stability for high-temperature applications. The sensors, which are manufactured from a stack of two silicon chips mounted via with gold–silicon (Au-Si) or aluminum–silicon (Al-Si) eutectic bonding, are shielded, miniaturized, and allow an operating temperature of up to 500 °C. Compared to conventional methods, the greatest benefit of the manufacturing process is that different sensor dimensions can be produced in the same batch for a wide measuring range, from mN to kN. The characterization of the realized sensors shows a high linearity and a low temperature drift of 99.992% FS and −0.001% FS/K at 350 °C, as well as a nonlinearity of 0.035% FS and a temperature drift of −0.0027% FS/K at 500 °C.

Research of MEMS pressure sensor stability with PDA-NFL circuit

“…The high response to capacitance changes when exposed to vibration is one of the main reasons why the capacitive method was not considered as a working method at the initial stage of this development. Also, despite the advantages of low power consumption, ease of fabrication and small chip size of capacitive pressure sensors, it has a very high nonlinearity error and require the mandatory use of an external processing circuit or ASIC to convert the capacitance into an electrical signal [18][19][20][21][22][23].…”