Effect of Ferroelectric/Metal Interface Structure on Polarization Reversal

The ferroelectric behaviors of vinylidene fluoride (VDF) oligomer thin films deposited on various bottom electrode materials (i.e., Au, Pt, Al, Al 2 O 3 /Al, and Al 2 O 3 /Au) were investigated. The coercive electric fields and full width at half maximum (FWHM) of the switching current peak of VDF oligomer thin films on the Au and Pt bottom electrodes were respectively lower and narrower than those of Al. These results indicate that the native oxide layer Al 2 O 3 on the Al electrode surface works as a linear capacitor on ferroelectric capacitors. However, ferroelectric capacitors using Au and Pt bottom electrodes have the tendency to easily break down with the sudden application of an electric field. Their polarization switching and fatigue lifetime are affected by electrode material and the ferroelectric/metal interface.