Fully symmetric vertical hall devices in CMOS technology

Abstract

We present a novel CMOS-integrated, vertical Hall sensor (VHS) with optimized symmetry for the measurement of in-plane magnetic field components. Due to the junction field effect, conventional five-contact VHS (5CVHS) suffer from considerable offsets caused by their inherent electrical asymmetry under contact permutations. The novel device achieves a higher degree of symmetry by the appropriate connection of four identical three-contact elements. As a result, with a bias voltage of 3.5 V and after current switching a mean residual offset of 2.5 μV with a standard deviation of 33.8 μV is achieved among 45 samples on an 8-inch wafer. This represents an improvement by a factor of more than 4 over 5CVHS fabricated on the same wafer. In addition, the power consumption is reduced by 47%.