CMOS Vertical Hall Magnetic Sensors on Flexible Substrate

This paper presents the realization of different vertical Hall sensors (VHSs) implemented using a 0.18- $\mu \text{m}$ CMOS technology and mounted on flexible substrates. Various geometries of VHS have been studied to obtain the optimum sensor device dimension and shape. COMSOL multiphysics simulation results are validated with respect to the electrical behaviour of an eight-resistor Verilog-A model implemented in Cadence environment. Simulation and measurement results are in good agreement. The use of polymeric foils and current spinning technique compensate for the effects caused by mechanical stress and possible fabrication imperfections. Measurement results for a low-offset basic VHS in planar state show a sensitivity of 59 ± 1 V(AT) $^{-1}$ in voltage mode and of $8~\pm ~0.1\%\text{T}^{-1}$ in current mode.