Influence of Frozen a-Domains on Hysteresis Properties of Ferroelectric Thin-Film Capacitors

Abstract

The influence of frozen a-domains which work as paraelectric layers on hysteresis properties was investigated using a double-layers model consisted of a ferroelectric layer and a paraelectric layer in series. As a result, it is found that a few frozen a-domains significantly degrade the hysteresis properties because switching charges derived by an applied voltage induce the voltage on the paraelectric layers and reduce the voltage applied to the ferroelectric layers. Strange behavior in the shift of hysteresis loops can be also explained by this model. The existence of frozen a-domains may be one of reasons why single phase ferroelectric thin-film capacitors with no interface layers sometimes show poor hysteresis properties.

Keywords:

• ferroelectric
• capacitor
• hysteresis
• frozen
• a-domain
• double-layers
• simulation

ACKNOWLEDGEMENTS

The authors would like to thank Prof. H. Funakubo and Mr. H. Morioka for informing permittivity of epitaxial PZT thin films with c- and a-axis orientations. This work was partly supported by a Grant-in-Aid for Scientific Research (C)(2) 15560277.