Design Considerations for CMOS-Integrated Hall-effect Magnetic Bead Detectors for Biosensor Applications

This dissertation presents a design methodology for on-chip magnetic bead label detectors based on Hall-effect sensors to be used for biosensor applications. Signal errors caused by the label binding process and other factors that place constraints on the minimum detector area are quantified and adjusted to meet assay accuracy standards. The methodology is demonstrated by designing an 8,192 element Hall sensor array implemented in a commercial 0.18 um CMOS process with single mask post-processing. The array can quantify a one percent surface coverage of 2.8 mum beads in thirty seconds with a coefficient of variation of 7.4%. This combination of accuracy and speed makes this technology a suitable detection platform for biological assays based on magnetic bead labels.