Imprint and Fatigue Properties of Chemical Solution Derived Pb_1–-xLa_x(Zr_yTi_1–y)_1–x/4O₃ Thin Films

Abstract

We have investigated the effect of oxygen vacancies on imprint and fatigue behavior of the PLZT thin films. It is found that the compensation of oxygen vacancies with various dopant concentrations and electrode structures is an important process parameter in determining the tendency to imprint and fatigue. In the case of PLZT thin films, the voltage shifts related to imprint are attributed to the trapping of electrons at ionic defect sites such as oxygen vacancies near the film/electrode interface, the magnitude of polarization, and concentration of defect-dipole complexes involving oxygen vacancies such as V 00Pb -V ≤≤ O . The strong dependence of fatigue rate on electrode material for PLZT thin films is due to the effect of the ferroelectric/electrode interaction on the pinning and/or unpinning rate involving the accumulation of oxygen vacancies near the film/electrode interface during fatigue cycling. By using RuO 2 as the top and/or bottom electrode instead of Pt, improved fatigue properties are obtained compared to Pt͞PLZT͞Pt capacitors. This is because a reduced accumulation of oxygen vacancies near the interface by the oxide electrode such as RuO 2 may reduce the electronic charge trapping and, consequently, lead to less domain wall pinning.

Leakage current and relaxation characteristics of highly (111)-oriented lead calcium titanate thin films

“…Another origin of the voltage shift is related to the magnitude of polarization. 14 The polarization constitutes an electrostatic potential well that attracts the electronic charge carriers, where they are trapped at near interfacial defect sites. A larger remanent polarization represents a deeper potential well, and consequently the trapping of charge carriers is more effective.…”

Electric response as a function of applied voltage of Bi3.25La0.75Ti3O12 thin films grown by pulsed-laser deposition

“…In order to clarify the interfacial problem, the frequency dependence of complex dielectric constant for some compounds in PZT and (Bi 2 O 2 ) 2+ (A m−1 B m O 3m+1 ) 2− systems has been studied. A remarkable low frequency dielectric dispersion below T c was observed in thin film capacitors of PZT [18], BST [19][20][21], Sr x Bi y Ta 2 O 9 (SBT) [8], Bi 2 Ti 2 O 7 [9], and Bi 4 Ti 3 O 12 [10]. It has been shown that this phenomenon greatly affects the electrical properties of the capacitors.…”

“…They proposed that the BLT thin film exhibits a fatigue-free characteristic and large remanent polarization. However, even if the BLT thin film is free from fatigue and imprint to simple Pt electrodes, they can also see an interfacial (electrode/bulk) problem similar to Pb(Zr x Ti 1−x )O 3 (PZT) [18] and (Ba, Sr)TiO 3 * Corresponding author. Tel.…”

Chemical solution deposition of ferroelectric lead lanthanum zirconate titanate films on base-metal foils

“…The incorporation of less-expensive base metals with high-κ dielectric is challenging. The high firing temperatures and oxidizing atmospheres necessary for synthesis and densification of many oxides can be detrimental to oxidationsensitive base metals, especially copper, whereas the reducing atmospheres that are favored by base metals can result in excessive defect concentrations and frustrated phase formation of the dielectric ceramic films [7,10]. These effects lead to unsatisfactory dielectric performance for practical applications.…”