Effect of Stress Due to Plastic Package Moisture Absorption in Hall Sensors

Commercial magnetic sensors based on the Hall effect are usually encapsulated in non-hermetic plastic packages. These plastic packages are known to swell in high humidity conditions due to moisture absorption. This swelling will modify the stress seen by the Hall sensor, causing the Hall sensitivity to be altered due to the piezo-Hall effect. The sensitivity drift, which is random in nature, may become the long-term stability limiting factor in high-end sensors. The objective of this work is to characterize in depth the sensitivity change due to moisture absorption and to review and implement two Hall sensitivity compensation methods.