Fully Integrated Back-Biased 3d Hall Sensor with Wafer-Level Integrated Permanent Micromagnets

This paper reports on a 3D Hall sensor back-biased by rare-earth micromagnets which are integrated directly into the silicon substrate using a wafer-level fabrication process, called PowderMEMS. For the first time, the technique is used to realize a fully integrated back-biased magnetic field sensor. The feasibility of the approach is proven by measurements of the motion of a rotating gear wheel which represents a typical back bias application. Additionally, the ability of the approach to create optimal magnetic field geometries for magnetically biased sensors is demonstrated.