Analysis of split-drain MAGFETs

We present fully three-dimensional simulation results of two-drain and three-drain magnetic field-effect transistors (MAGFET), magnetic sensors based on metal-oxide-semiconductor field-effect transistor (MOSFET) structures. By proper development and discretization of the current density equations comprising the nonzero magnetic field components, a two-drain MAGFET is analyzed at both 77 K and 300 K. The discretization scheme is implemented in the general purpose multidimensional device and circuit simulator MINIMOS-NT which is used to investigate the relative sensitivity, the main figure of merit of any magnetic sensor, as a function of the geometric parameters and bias conditions. Besides, the physical modeling of silicon at 77 K and the Hall scattering factors for the silicon inversion layers are discussed. Our simulation results perfectly match the available experimental data. New in-depth knowledge can be obtained by simulating MOSFET structures at 77 K in the presence of an arbitrary magnetic field.