The interface screening model as origin of imprint in PbZrxTi1-xO3 thin films.: II.: Numerical simulation and verification

In this article, the interface screening model is theoretically discussed which explains imprint in ferroelectric thin films caused by a large electric field within a surface layer with deteriorated ferroelectric properties. During aging this field is gradually screened by electronic charges. Different screening mechanisms such as charge injection from the electrodes into the film as well as charge separation within the surface layer are considered by implementing a numerical simulation based on the different screening mechanisms. A comparison between experimental and simulation results is presented. The best agreement between experiment and simulation is obtained for a Frenkel-Poole type charge separation mechanism within the surface layer. The simulation results indicate relatively shallow trap states (0.35 eV) and a surface layer extension of approximately 5 nm. (C) 2002 American Institute of Physics.