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Split-contact magnetoresistors (SCMs) are Hall effect sensors based on the current deflection effect of the magnetic field. We developed a simulation model of Hall sensors, including SCM, in COMSOL Multiphysics considering the transport mechanisms of diffusion and drift. We can simulate devices with a quite arbitrary shape. We use the magnitude of the current density in the deflection direction (on the longitudinal line of symmetry of the device) as a useful guide for the study of the effects of the geometry on the sensitivity to the magnetic field. Other than rectangular shapes, we propose a device with a Venturi-tube shape to increase the sensitivity of magnetoresistors.

This work presents an analytical methodology to estimate the equivalent rectangular aspect ratio of the active region of a SplitDrain MAGFET (SD-MAGFET) by combining known active regions. With this result, a SPICE Macro Model (SMM) for SDMAGFETs is proposed associating each drain to a MOSFET. The effect of the magnetic flux density is introduced through the substrate-source voltage of each MOSFET, in opposite sense from each other, establishing different channel concentration. The total DC drain current of the equivalent rectangular MOSFET obtained in HSPICE has an error <15% with respect to results experimenttally measured for SD-MAGFETs of W=10µm and different L (2µm, 5µm and 15µm). The drain current imbalance obtained in HSPICE using the proposed SMM has an error <1,6% with respect to results experimentally measured with a SD-MAGFET of W/L=10µm/2µm.

In this paper we show that silicon split-contact magnetoresistors with geometric dimensions of the order of the Debye length (LD) can have much higher sensitivities than the usual devices with much larger length and width than LD. Numerical simulations carried out with Comsol Multiphysics show that silicon n-type magnetoresistors with dimensions of the order of LD can have magnetic sensitivity as high as 60%/T which is ten times higher than usual sensitivities.