基于极化反转函数的铁电电容器件模型

Device Model of Ferroelectric Capacitor Based on Polarization Reversal Function

通过分析铁电薄膜微观结构及铁电畴在外电场作用下极化反转机理,将铁电畴等效为一群具有相互独立矫顽场的铁电偶极子.采用几何方法,解释了这些偶极子在不规则电压波形驱动下极化反转的规律.在此基础上,引入铁电电容的极化反转函数来表征铁电电容宏观极化强度随外电场变化的数学表达式.该函数的引入不仅简化了模型的计算量,还成功避免了同类模型中数值微分和数值积分所带来的误差,大大提高了模型精确性.

Based on the microstructure and the domain reversal behavior of ferroelectric thin films,the ferroelectric domains are abstracted as a cluster of dipoles. Each dipole has self-independent coercive field,and the complicated mechanism of their polarization switching under random signal is considerably facilitated by a geometric interpretation. Then, we introduce the concept of polarization switching function to represent the relation between the macroscopical polarization and electric field. The polarization switching function also help to simply the computation and avoid the enhanced errors from the differentiations of experimental data. A model based on polarization reversal function is developed, which has explicit physical background and concise mathematical formalism.