Leakage currents in porous PZT films

AbstractFerroelectric (FE) films, especially PZT films, have received increasing attention for microelectronic applications such as ferroelectric memory and high density DRAM. There has been significant progress in the preparation of high quality PZT films involving wet chemical and physical vapor deposition techniques. Metal-FE-metal structures, typified by Pt-PZT-Pt capacitors, are the basic building blocks for the ferroelectric devices. The leakage currents of the capacitors are known to be non-ohmic and exhibit an exponential dependence on applied voltage.The present paper presents a model based on totally depleted back-to-back Shottky barriers. Predictions based on the model can provide significant new understanding of the FE behavior of thin films. For example, the assumption of total depletion leads to the presence of a built-in field within the film which can explain the ubiquitously higher values of coercive field in FE films than found in bulk ceramics. It will be shown that the agreement between model predictions and actual device I-V characteristics of Pt-PZT-Pt capacitors is very close. Further, the model can also explain the observed hysteresis loop asymmetry and low dielectric constants of films of relaxor FE's, whose dielectric constants are much smaller than those of bulk materials.

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Porous PZT Films Prepared by PVP Assisted Sol-Gel Process

Ferroelectrics ◽

10.1080/00150193.2015.1059680 ◽

2015 ◽

Vol 484 (1) ◽

pp. 43-48 ◽

Cited By ~ 4

Author(s):

D. Seregin ◽

K. Vorotilov ◽

A. Sigov ◽

N. Kotova

Keyword(s):

Sol Gel ◽

Sol Gel Process ◽

Pzt Films ◽

Porous Pzt

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Ion beam etching of dense and porous PZT films

Ferroelectrics ◽

10.1080/00150193.2019.1598188 ◽

2019 ◽

Vol 544 (1) ◽

pp. 75-81

Author(s):

D. A. Abdullaev ◽

D. S. Seregin ◽

K. A. Vorotilov ◽

A. S. Sigov

Keyword(s):

Ion Beam ◽

Ion Beam Etching ◽

Pzt Films ◽

Porous Pzt

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Microstructural and Electrical Properties of Ferroelectric Capacitors with Pt/RuO2 Hybrid Electrodes

MRS Proceedings ◽

10.1557/proc-361-229 ◽

1994 ◽

Vol 361 ◽

Cited By ~ 4

Author(s):

H.N. Al-Shareef ◽

Y.L. Chen ◽

O. Auciello ◽

A.I. Kingon

Keyword(s):

Leakage Current ◽

Sol Gel ◽

Second Phase ◽

Leakage Currents ◽

Barrier Heights ◽

Pzt Film ◽

Sol Gel Process ◽

Pzt Films ◽

Pyrochlore Type ◽

Ferroelectric Capacitors

ABSTRACTThin films of pb(Zr0.53Ti0.47)O3 (PZT) grown in our laboratory on RuO2 electrodes by the sol-gel process are characterized by high leakage currents and by the presence of a pyrochlore-type second phase. We have used a thin Pt interlayer between the PZT film and RuO2 bottom electrode to produce RuO2/PZT/100ÅPt/RuO2/SiO2/Si capacitor structures. It is found that use of such a Pt interlayer significantly reduces or eliminates the second phase in the PZT films, and lowers their leakage currents by more than four orders of magnitude. At the same time, the excellent resistance to polarization fatigue characteristic of the RuO2/PZT/RuO2 capacitors is maintained. The microstructures of PZT films grown on RuO2 electrodes with and without the 100Å Pt interlayer are compared. In addition, the voltage, temperature, and polarity dependence of the leakage current in these samples was measured. The data suggest that leakage current in these samples is most likely Schottky emission controlled. The barrier heights are determined to be about 0.80 and 0.73 eV for the top and bottom interfaces, respectively.

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Discharge currents in dense and porous PZT films

Ferroelectrics ◽

10.1080/00150193.2019.1598192 ◽

2019 ◽

Vol 544 (1) ◽

pp. 82-87

Author(s):

Yu. V. Podgorny ◽

A. N. Antonovich ◽

K. A. Vorotilov ◽

A. S. Sigov

Keyword(s):

Pzt Films ◽

Porous Pzt

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Studies of Asymmetric Hysteresis Loops and Leakage Current Behaviors in Pt/Al2O3/SiO2/Si /PZT/Au Structures Prepared by MOCVD Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.110-116.294 ◽

2011 ◽

Vol 110-116 ◽

pp. 294-298

Author(s):

A. Masruroh ◽

Masayuki Toda

Keyword(s):

Leakage Current ◽

Hysteresis Loops ◽

Test System ◽

Leakage Currents ◽

Pt Electrode ◽

Positive Direction ◽

Polarization Voltage ◽

Asymmetric Behavior ◽

Pzt Films ◽

Current Behavior

The polarization-voltage (P-V) and leakage currents density (J-V) characteristics were investigated on the ferroelectric PZT films deposited on Pt/Al2O3/SiO2/Si substrate with a vapor-deposited gold top electrode. The P-V hysteresis loops and the J-V characteristics were measured after performing a rapid thermal annealing (RTA) process. A ferroelectric test system (Precision LC Radiant Technology) was used to measure their electrical properties with a 90-nm PZT thickness and an area of 7.85 x10-5 cm2. The measurements were taken by connecting a Pt bottom electrode to the drive of the precision LC and the Au top electrode to the drive of the precision LC. The P-V hysteresis and J-V characteristics of PZT samples showed the asymmetry for both measurements. The asymmetric hysteresis loops and leakage current behavior were shifted in the positive direction when the drive was applied to the Pt electrode, while being negatively shifted in the converse case. The asymmetric behavior of the polarized state in the hysteresis loops due to the electrode configuration resulted from different work function between the Pt and Au electrodes, further influencing the leakage current behavior.

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Dielectric and piezoelectric properties of dense and porous PZT films prepared by sol-gel method

Journal of Sol-Gel Science and Technology ◽

10.1007/s10971-007-0739-3 ◽

2007 ◽

Vol 42 (3) ◽

pp. 397-405 ◽

Cited By ~ 8

Author(s):

Yutaka Ohya ◽

Yuki Yahata ◽

Takayuki Ban

Keyword(s):

Piezoelectric Properties ◽

Sol Gel ◽

Gel Method ◽

Sol Gel Method ◽

Pzt Films ◽

Dielectric And Piezoelectric Properties ◽

Porous Pzt

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Effects of Rare Earth Incorporation on the Ferroelectric and Dielectric Properties of Sol-Gel Derived PbTiO3 Films

MRS Proceedings ◽

10.1557/proc-346-291 ◽

1994 ◽

Vol 346 ◽

Author(s):

G. Teowee ◽

C.D. Baertlein ◽

S.A. Schlegel ◽

J.M. Boulton ◽

D.R. Uhlmann

Keyword(s):

Dielectric Constant ◽

Rare Earth ◽

Remanent Polarization ◽

Sol Gel ◽

Dissipation Factor ◽

Leakage Currents ◽

Dielectric Characterization ◽

Low Leakage ◽

Pzt Films ◽

Rare Earth Doped

ABSTRACTFerroelectric (FE) films, especially PZT films, have received increasing attention for microelectronics applications such as FE memory and in high density DRAM's. While rare earth doped PbTiO3 ceramics has been studied for SAW and piezoelectric applications, rare earth-doped films seldom have been systematically explored. A series of sol-gel derived PbTiO3 films with varying amounts (5-15 mole %) of rare earths (such as, Nd, Sm, Tb, Dy, Er ,Yb and La ) have been prepared using acetates and alkoxides as precursors. The solutions were spin coated onto platinized Si wafers. The effects of the type and amount of rare incorporation on the phase assembly and microstructure have been quantified. The results of dielectric characterization (e.g., dielectric constant, dissipation factor and leakage currents) and FE behaviors (viz remanent polarization, and coercive field) are presented; these films exhibited low leakage currents (3E-10 A/cm2) and much higher dielectric constant (up to 525) compared to undoped PbTiO3 films.

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Electron microscopy studies of PZT ferroelectric film capacitor structures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131450 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1364-1365

Author(s):

V. Kaushik ◽

P. Maniar ◽

J. Olowolafe ◽

R. Jones ◽

A. Campbell ◽

...

Keyword(s):

Electric Fields ◽

Sol Gel ◽

Ferroelectric Material ◽

Dielectric Constants ◽

Dielectric Films ◽

Lead Zirconium Titanate ◽

Si Substrate ◽

Film Capacitor ◽

Pzt Films ◽

High Dielectric

Lead zirconium titanate films (Pb (Zr,Ti) O3 or PZT) are being considered for potential application as dielectric films in memory technology due to their high dielectric constants. PZT is a ferroelectric material which shows spontaneous polarizability, reversible under applied electric fields. We report herein some results of TEM studies on thin film capacitor structures containing PZT films with platinum-titanium electrodes.The wafers had a stacked structure consisting of PZT/Pt/Ti/SiO2/Si substrate as shown in Figure 1. Platinum acts as electrode material and titanium is used to overcome the problem of platinum adhesion to the oxide layer. The PZT (0/20/80) films were deposited using a sol-gel method and the structure was annealed at 650°C and 800°C for 30 min in an oxygen ambient. XTEM imaging was done at 200KV with the electron beam parallel to <110> zone axis of silicon.Figure 2 shows the PZT and Pt layers only, since the structure had a tendency to peel off at the Ti-Pt interface during TEM sample preparation.

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