7.2.1 Operating Principle

The FEMFET technology is still in an early prototype phase, so no canonic sensing scheme exists to the date of this thesis. This subsection introduces a straightforward way to utilize the hysteresis properties of the gate dielectric.

During write operation a positive or negative pulse is applied to the gate, which will orient the dipoles in the gate dielectric either in the up or down direction. Due to the ferroelectric properties, they will keep their orientation after the write pulse has ended and the gate voltage drops back to zero. The impact of the resulting dipole moment on the charge distribution in the channel is schematically outlined in  Fig. 7.10 and Fig. 7.11.

If the device is designed in a way that the threshold voltage is near zero, this will have drastic consequences to the drain current of the device. In the ON state a significant current will be detectable, where as in the OFF state the device is driven deep into the subthreshold regime.

Figure 7.10: ON state of the FEMFET

Figure 7.11: OFF state of the FEMFET