A smart accelerometer with on-chip electronics fabricated by a commercial CMOS process

Piezoresistive accelerometers with a monolithically integrated operational amplifier werc produced, the fabrication process based on a commerial 3 Mym CMOS process. The mecahnical structures were realized using wet anisotropic etching of silicon with KOH and the electrochemical etch-stop at p-n junctions. Measurements show that the integration of these necessary micromachining process steps into the IC process do not influence the parameters of the electronic devices. Also, the parameters of the mechanical structures are comparable to discrete devices. The realization of application-specific smart mechanical sensors and actuators using a standard CMOS process is now possible.