Monolithic Sensor Integration in CMOS Technologies

Abstract

Besides being mainstream for mixed-signal electronics, CMOS technology can be used to integrate MEMS on a single die, taking advantage of the structures and materials available in feature sizes around 180 nm. In this article, we demonstrate that the CMOS Back End Of Line (BEOL) layers can be postprocessed and be opportunistically used to create several kinds of MEMS sensors exhibiting good or even excellent performance, such as accelerometers, pressure sensors and magnetometers. Despite the limitations of the available mechanical and material properties in CMOS technology, thanks to monolithic integration, these are compensated by the significant reduction of parasitics and system size. Furthermore, this work opens the path to create monolithic integrated multi-sensor (and even actuator) chips, including data fusion and intelligent processing.