  The effect of polarization rotation on the performance of metal oxide
semiconductor field-effect transistors was investigated with a
Landau-Ginzburg-Devonshire theory based model. In this analytical model,
depolarization field, polarization rotations and the electrostatic properties
of the doped silicon substrate are considered to illustrate the size effect of
ferroelectric oxides and the stability of polarization in each direction. Based
on this model, we demonstrate that MOSFET operation could be achieved by
polarization reorientation with a low operating voltage, if the thickness of
ferroelectric oxide is properly selected. Polarization reorientation can boost
the surface potential of the silicon substrate, leading to a subthreshold swing
S lower than 60 mV/decade. We believe that this model could provide guidance in
designing electronic logic devices with low operating voltages and low active
energy consumption.
