Downscaling of Pb(Zr,Ti)O3 film thickness for low-voltage ferroelectric capacitors: Effect of charge relaxation at the interfaces

2000 ◽  
Vol 88 (4) ◽  
pp. 2154-2156 ◽  
Author(s):  
I. Stolichnov ◽  
A. Tagantsev ◽  
E. Colla ◽  
S. Gentil ◽  
S. Hiboux ◽  
...  
Keyword(s):  
Film Thickness ◽  
Low Voltage ◽  
Charge Relaxation ◽  
Ferroelectric Capacitors

Low-Voltage Pb(Zr,Ti)O3 Film Capacitors: Control of Charge Relaxation at the Interfaces

1999 ◽  
Vol 596 ◽  
Author(s):  
I. Stolichnov ◽  
A. Tagantsev ◽  
S. Gentil ◽  
S. Hiboux ◽  
P. Muralt ◽  
...  
Keyword(s):  
Size Effects ◽  
Low Voltage ◽  
Charge Injection ◽  
Fatigue Performance ◽  
Charge Relaxation ◽  
Positive Effects ◽  
Pzt Film ◽  
Electrode Interface ◽  
Ferroelectric Capacitors ◽  
Ferroelectric Switching

AbstractIt is suggested that the processes of charge injection and entrapment at the interfacial layer of Pb(Zr,Ti)O3 (PZT) film capacitors are responsible for both polarization fatigue and size effects on ferroelectric switching. The study of the charge injection by analyzing the dependence of coercive field on maximum polarization shows that there is a direct relationship between the charge injection properties and fatigue performance. Based on our results, we conclude that enhancement of charge relaxation at the interfaces of PZT capacitors results in two positive effects: improvement of polarization fatigue performance and suppression of size effects on ferroelectric switching, which are detrimental for low-voltage PZT film capacitors.This idea has been implemented experimentally by introducing a thin RuO2 layer into the top-electrode interface of the Pt/PZT/Pt capacitor. PZT film capacitors of 100–170 nm thickness prepared in this way exhibited substantially improved fatigue in combination with weak size effects, which allows reduction of the operation voltage down to 0.8 V without degradation of the hysteresis properties. Our results show that the control of charge relaxation at the interface is a key issue for development of the low-voltage ferroelectric capacitors.

Lead based ferroelectric capacitors for low voltage non-volatile memory applications

1998 ◽  
Vol 19 (1-4) ◽  
pp. 159-177 ◽  
Author(s):  
S. Aggarwal ◽  
A. S. Prakash ◽  
T. K. Song ◽  
S. Sadashivan ◽  
A. M. Dhote ◽  
...  
Keyword(s):  
Low Voltage ◽  
Non Volatile Memory ◽  
Volatile Memory ◽  
Memory Applications ◽  
Ferroelectric Capacitors

scholarly journals Thin-film chemical expansion of ceria based solid solutions: laser vibrometry study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hendrik Wulfmeier ◽  
Dhyan Kohlmann ◽  
Thomas Defferriere ◽  
Carsten Steiner ◽  
Ralf Moos ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
High Temperature ◽  
Film Thickness ◽  
Solid Solutions ◽  
Low Voltage ◽  
Excitation Frequency ◽  
Dimensional Change ◽  
Potential Core ◽  
Chemical Expansion

Abstract The chemical expansion of Pr0.1Ce0.9O2–δ (PCO) and CeO2–δ thin films is investigated in the temperature range between 600 °C and 800 °C by laser Doppler vibrometry (LDV). It enables non-contact determination of nanometer scale changes in film thickness at high temperatures. The present study is the first systematic and detailed investigation of chemical expansion of doped and undoped ceria thin films at temperatures above 650 °C. The thin films were deposited on yttria stabilized zirconia substrates (YSZ), operated as an electrochemical oxygen pump, to periodically adjust the oxygen activity in the films, leading to reversible expansion and contraction of the film. This further leads to stresses in the underlying YSZ substrates, accompanied by bending of the overall devices. Film thickness changes and sample bending are found to reach up to 10 and several hundred nanometers, respectively, at excitation frequencies from 0.1 to 10 Hz and applied voltages from 0–0.75 V for PCO and 0–1 V for ceria. At low frequencies, equilibrium conditions are approached. As a consequence maximum thin-film expansion of PCO is expected due to full reduction of the Pr ions. The lower detection limit for displacements is found to be in the subnanometer range. At 800 °C and an excitation frequency of 1 Hz, the LDV shows a remarkable resolution of 0.3 nm which allows, for example, the characterization of materials with small levels of expansion, such as undoped ceria at high oxygen partial pressure. As the correlation between film expansion and sample bending is obtained through this study, a dimensional change of a free body consisting of the same material can be calculated using the high resolution characteristics of this system. A minimum detectable dimensional change of 5 pm is estimated even under challenging high-temperature conditions at 800 °C opening up opportunities to investigate electro-chemo-mechanical phenomena heretofore impossible to investigate. The expansion data are correlated with previous results on the oxygen nonstoichiometry of PCO thin films, and a defect model for bulk ceria solid solutions is adopted to calculate the cation and anion radii changes in the constrained films during chemical expansion. The constrained films exhibit anisotropic volume expansion with displacements perpendicular to the substrate plane nearly double that of bulk samples. The PCO films used here generate high total displacements of several 100 nm’s with high reproducibility. Consequently, PCO films are identified to be a potential core component of high-temperature actuators. They benefit not only from high displacements at temperatures where most piezoelectric materials no longer operate while exhibiting, low voltage operation and low energy consumption.

Reliability Properties of Low-Voltage Ferroelectric Capacitors and Memory Arrays

2004 ◽  
Vol 4 (3) ◽  
pp. 436-449 ◽  
Author(s):  
J.A. Rodriguez ◽  
K. Remack ◽  
K. Boku ◽  
K.R. Udayakumar ◽  
S. Aggarwal ◽  
...  
Keyword(s):  
Low Voltage ◽  
Memory Arrays ◽  
Ferroelectric Capacitors

Charge relaxation at the interfaces of low-voltage ferroelectric film capacitors: Fatigue endurance and size effects

2001 ◽  
Vol 258 (1) ◽  
pp. 221-230
Author(s):  
Igor Stolichnov ◽  
Alexander Tagantsev ◽  
Enrico Colla ◽  
Nava Setter
Keyword(s):  
Size Effects ◽  
Low Voltage ◽  
Ferroelectric Film ◽  
Charge Relaxation ◽  
Fatigue Endurance
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