Development process for MEMS pressure sensors for standarized CMOS read-out circuitry

Abstract

Pressure sensor systems can be realized by the combination of two different technologies: CMOS-technology for the electrical part and MEMS-technology for the pressure sensor part. The challenge is to design the pressure sensor cell in such a way that a wide pressure range can be covered with one fix lateral membrane size, as any change in this lateral dimensions would lead to a new CMOS design, resulting in high costs. The authors describe an approach how to realize pressure sensor systems that on one hand are able to measure a nominal pressure range of several bar, but also to measure in the low pressure range of only several tenth of mbar by keeping a sufficient signal to noise ratio, and without changing the original CMOS circuitry. For the calculation of the sensor signals, an analytical approach, based on the theory of piezoresistivity, is combined it with structural mechanical simulation of mechanical stress, utilizing finite element analysis.