Computation of the polarization due to the ferroelectric layer in a stacked capacitor from Sawyer-Tower hysteresis measurements

Reducing thickness of thin ferroelectric films typically comes with an apparent degradation of their dielectric and ferroelectric properties. In practice one observes a marked decrease of the linear dielectric constant and of remanent and maximum polarizations which may arise from the presence of passive layers at the film interfaces. We propose a numerical procedure which allows us to investigate the genuine behavior of switching domains in the ferroelectric layer of a stacked capacitor. This is achieved owing to the computation of the ferroelectric polarization from Sawyer-Tower hysteresis measurements. Moreover, the proposed procedure simultaneously allows us to remove the possible loop deformations through a numerical compensation acting as a modified Sawyer-Tower (ST) circuit. The method is based on a suitable formulation of the polarization taking place in the ferroelectric layer which corrects for both the passive layer effect and for the parasitics of the ST circuit. In addition, a fit procedure is described from which may be derived the linear dielectric constant of the ferroelectric layer, the resistivity, and the interfacial capacitance of the stacked capacitor. (C) 2003 American Institute of Physics.