Octagonal geometry Hall plate designed for the PiezoHall effect measurement

Hall Effect transducers are the most popular kind of magnetic sensor; however, the offset voltage and drift of their characteristic have limited their usability. The main source of variation is the remaining mechanical stress in the crystalline silicon structure, related to the piezoresistive effect of the semiconductor materials, which can influence the offset and also the sensitivity of the device. This work is going to introduce an eight terminal hall plate fabricated using a commercial CMOS process, which can be used to study the different effects in the hall sensor in the main crystallographic directions. We also applied an offset reduction based in current spinning technique using the 8 terminals device and an on-chip control circuit. Finally, we show the design of the Hall plate over a silicon membrane which is suitable to measure the cross side effect between both hall and piezoeffect, which is called PiezoHall effect.