  In this letter, the transient behavior of a ferroelectric (FE)
metal-oxide-semiconductor (MOS) capacitor is theoretically investigated with a
series resistor. It is shown that compared to a conventional high-k dielectric
MOS capacitor, a significant inversion charge-boost can be achieved by a FE MOS
capacitor due to a steep transient subthreshold swing (SS) driven by the free
charge-polarization mismatch. It is also shown that the observation of steep
transient SS significantly depends on the viscosity coefficient under Landau's
mean field theory, in general representing the average FE time response
associated with domain nucleation and propagation. Therefore, this letter not
only establishes a theoretical framework that describes the physical origin
behind the inversion charge-boost in a FE MOS capacitor, but also shows that
the key feature of depolarization effect on a FE MOS capacitor should be the
inversion-charge boost, rather than the steep SS (e.g., sub-60mV/dec at room
temperature), which cannot be experimentally observed as the measurement time
is much longer than the FE response. Finally, we outlines the required material
targets for the FE response in field-effect transistors to be applicable for
next-generation high-speed and low-power digital switches.
