Failure Analysis of FeCAPs. Electrical Behaviour Under Synchrotron X-Ray Irradiation

Abstract

This paper presents a preliminary study of the degradation and restoration of ferroelectric properties under X-ray irradiation of Pt/SBT/Pt ferroelectric capacitors (FeCAP) and the degradation in Pt/PZT/Pt FeCAPs. The results seem to point out that aging of irradiated capacitors originates from the pinning of domain walls due to trapping of photo-generated carriers at domain boundaries. For SBT FeCAPs, the recovery of a significant switchable polarisation after electrical cycling under X-ray irradiation indicates that the domain walls are probably weakly pinned. In PZT FeCAPs, the fatigue behaviour during X-ray exposure can be explained as a result of X-ray induced acceleration of the bulk screening process due to increasing of the concentration of bulk carriers, which leads to both static and kinetic imprint effects.

Keywords:

• Ferroelectric capacitors
• failure analysis
• PZT and SBT
• synchrotron
• X-ray radiation hardness

ACKNOWLEDGEMENTS

Authors are grateful to T. Schneller who fabricated the investigated PZT films. Part of this work is funded by the IST FLEUR project founded by European Community (“FerroeLectric for EURope,” IST-2000-30153).