Implementation of a ferroelectric capacitor model using the preisach hysteresis theory

Abstract

The design of the new ferroelectric memories requires a ferroelectric capacitor model that should be easy to incorporate in a circuit simulator and easy to calibrate based on the experimental measurements. Such a model can be developed by applying the Preisach theory of hysteresis to ferroelectric materials. This theory assumes a distribution of the ferroelectric coercitive voltages. This paper presents the Preisach model and its implementation for the ferroelectric materials based on the experimental determination of the bidimensional Preisach distribution. The relaxation current of the ferroelectric capacitor is also incorporated in the model. Relaxation plays an important roll in the frequency response of these materials. The whole model was implemented into the Spectre® circuit simulator. The simulations of the hysteresis loops show a good agreement with the experiment even for partial hysteresis loops. The memory cell simulations show that the model can be successfully used for the real memory design.

Key Words:

• ferroelectric capacitor
• modeling
• Preisach
• relaxation current