Exploiting magnetic sensing capabilities of Short Split-Drain MAGFETs

The magnetic sensing capabilities of Split-Drain MAGFETs (SD-MAGFETs) with a channel that is a short Hall plate, herein called Short Split-Drain MAGFETs, are analyzed. In addition to the current-lines deflection effect, this paper shows that the magnetoresistance effect also contributes to establish the sensitivity of Short SD-MAGFETs. A relationship between the forces acting on the deflection direction and a model of the Hall angle are developed showing that these effects are favored notoriously when L/W ⩽ 0.27. Furthermore, the magnetoresistance effect improves the sensitivity when the channel length is reduced. This allows to design a high-sensitivity SD-MAGFET with a reduced active area. Using the proposed model of the Hall angle with a continuous model of the geometric correction factor, a continuous variation of the Hall angle along the channel for any L/W can be obtained, and a quantitative criterion to establish which range of the L/W values corresponds to a short Hall plate and which one to a long Hall plate can be established. In order to validate the proposed design criteria, a Short SD-MAGFET with L/W = 0.2 and W/L = 10 μm/2  μm has been characterized. Sensing capabilities from 90 μT to 27 μT and sensitivities from 15.51% to 59.9% have been experimentally obtained at room temperature and in strong inversion.