4.1 The Structure

A two-drain MAGFET is a magnetic sensor based on a MOSFET. Its structure is identical to a MOSFET but the drain is split in two or more parts [25,33,42]. In this chapter, a two-drain MAGFET built with a 10 $\mu$m standard CMOS process will be analyzed. The substrate doping is of $1\times 10^{15}\; \mathrm{cm}^{-3}$ and the oxide thickness is of 60 nm. The metallurgical junction is of 1 $\mu$m and the source/drain doping is of $5\times 10^{18}\; \mathrm{cm}^{-3}$. The structure was built at the National Institute for Astrophysics, Optics, and Electronics (INAOE) Tonantzintla, Puebla, Mexico and measurements were carried out by Dr. Edmundo A. Gutiérrez-Domínguez. Some results are shown in reference [33]. In the following analysis the investigated MAGFET has a $W/L$ ratio of $0.8$ ( $W = 100\,\mu$m and $L = 125\,\mu$m) and a distance between the drains of $10\,\mu$m.

Figure 4.1: Two-drain MAGFET structure.