Physics based fatigue compact model for ferroelectric capacitors

Abstract

A physics based compact model describing the fatigue behavior of ferroelectric capacitors has been developed. Fatigue is a gradual decrease of detectable polarization with increasing number of polarization cycles. This can be caused by trapped charges which pin dipoles near the interface to the electrode. In order to polarize those pinned dipoles they have to be separated from the trapped charges by a higher electrical force. This force has been described in our model by additional coercive voltages representing the different polarization response of the dipoles in the interface region in contrast to those in the inner region of the ferroelectric capacitor. Our model has been implemented into a common-used circuit simulator showing good agreement with measurements.

A model of ferroelectric behavior based on a complete switching density

“…It is shown that this assumption is not valid when the material is subjected to a ''local imprint'' phenomenon. 11 The experimental PD shown in Fig. 6͑a͒ seems to be a two-dimensional-Gaussian distribution.…”