CMOS-SOI-MEMS Uncooled Infrared Security Sensor With Integrated Readout

A new generation of uncooled passive infrared (PIR) security sensors based on a suspended thermal transistor MOS (TMOS), fabricated in standard CMOS-SOI process, released by post-etching, and wafer level packaged achieving a vacuum of <;4 Pa, has been developed at the Technion. One of the important features of TMOS is very low power consumption (in this case, ~2-4 nWatt) due to its subthreshold operation requiring ~10 nA at 0.2 V, enabling wide range of battery applications. This paper focuses on the analog design of monolithically integrated readout for the electronic system, formed by the PIR sensor, its front-end analog interface and the processing circuitry. The measured signal-to-noise ratio of this system is 100-200, depending on the operation point, at the black-body temperature of 50° C, while the total input referred noise is ≤1 μVrms and the total system current consumption is no more than 20 μA. The sensors and read-out are processed with the same CMOS-SOI technology.