3D Lorentz force magnetic sensor using ultra-thin piezoresistive cantilevers

This paper reports on a Lorentz force-based triaxial magnetometer using three ultra-thin cantilevers. Instead of wholly fabricating 300nm-thick cantilever sets in plane, one of them is erected with a principle of residual stress of multi-layer to measure an out-of-plane magnetic field. In addition to realizing the highest sensitivity of ultra-thin piezo-resistive cantilevers, sensing characteristics of each direction are also comparable. With 10-mA direct excitation current, the sensor exhibits 3-axis magnetically sensing capability with an average sensitivity of ΔR/R₀=2.63 A^-1 T^-1, resolution of 1mT, and power consumption less than 11mW. The proposed sensor is versatile enough to serve various demands of magnetically measuring works.