High Sensitivity InSb Ultra-Thin Film Micro-Hall Sensors for Bioscreening Applications

A high sensitivity, 4.5 µm×4.5 µm InSb thin film micro-Hall sensor (micro-HS) with a minimum field detection ( B min ) of 77 nT/(Hz) 1/2 was developed for bioscreening applications and used for the detection of a single 2.8 µm diameter superparamagnetic microbead by monitoring its ac magnetic susceptibility. The scalability of the InSb micro-HS was demonstrated by fabricating 500 nm×500 nm InSb nano-Hall sensors with B min of 0.72 µT/(Hz) 1/2 that could potentially be used to detect 100 nm sized superparamagnetic particles.