A Retention Model for Ferroelectric-Gate Field-Effect Transistor

By combining the basic device equations of metal-oxide-semiconductor field-effect transistors with the polarization retention characteristics of ferroelectric thin films, a retention model for ferroelectric-gate field-effect transistor (FeFET) is developed based on the depolarization field of the ferroelectric. This model gives the retention characteristics of FeFET both in short and long time scales. Simulations demonstrate that large polarization will result in large depolarization field, which causes fast polarization loss in turn. The retention characteristics of the off-state is poorer than that of the on-state for p-FeFET, because the depolarization field in accumulation state is much larger than that in strong inversion state. Further analysis indicates that an appropriate holding voltage could be used to restrain the depolarization field in accumulation state to improve the retention characteristics of p-FeFET.