0.2 mT Residual offset of CMOS integrated vertical Hall sensors

A residual offset lower than 0.2 mT is obtained with a CMOS integrated vertical Hall (VH)-sensor microsystem. Instead of the conventional design with five contacts in the sensor active area, we apply a layout with only four contacts. This design shows a higher effectiveness for the offset reduction by the spinning current (SC) method, because of the symmetrical current flow for the two different biasing phases. Furthermore, to obtain very low offsets, coupled sensors are integrated with the spinning current electronics in the final microsystem. A sensitivity up to S v=0.025 V/VT is achieved for these sensors without any additional technology step. The measured output noise level of the integrated microsystem (1.9 μT/ Hz ) is in the usual range of commercial integrated Hall-sensors. Our new developments open the way to the realization of compact, low-cost angular sensors with 10 bit resolution.