Z-contrast and electron energy loss spectroscopy study of passive layer formation at ferroelectric PbTiO3∕Pt interfaces

Scanning transmission electron microscopy and electron energy loss spectroscopy have been applied to investigate the possible structural origins of ferroelectric polarization degradation at PbTiO3∕Pt interfaces. The microscopic analysis revealed that an amorphous Ti-rich interfacial layer as well as nanometer size precipitates was formed at PbTiO3∕Pt interfaces. The interfacial layer appears to form through decomposition of the PbTiO3 film due to a ferroelectric-electrode reaction during Pt deposition. The formation of the interfacial layer and precipitates could contribute to the polarization degradation typically observed for Pt-electroded PbTiO3-based ferroelectric capacitors.