Effect of LaNiO3 electrode on microstructural and ferroelectric properties of Bi3.25Eu0.75Ti3O12 thin films

Ferroelectric SrBi2Ta2O9 (SBT) thin films on Pt/ZrO2/SiO2/Si were successfully prepared by using an alkanolamine-modified chemical solution deposition method. It was observed that alkanolamine provided stability to the SBT solution by retarding the hydrolysis and condensation rates. The crystallinity and the microstructure of the SBT thin films improved with increasing annealing temperature and were strongly correlated with the ferroelectric properties of the SBT thin films. The films annealed at 800 °C exhibited low leakage current density, low voltage saturation, high remanent polarization, and good fatigue characteristics at least up to 1010 switching cycles, indicating favorable behavior for memory applications.

Download Full-text

Improvement of Ferroelectric Properties of Lead Zirconate Titanate Thin Films by Ion-substitution using Rare-earth Cations

MRS Proceedings ◽

10.1557/proc-830-d3.3 ◽

2004 ◽

Vol 830 ◽

Author(s):

Hiroshi Nakaki ◽

Hiroshi Uchida ◽

Shoji Okamoto ◽

Shintaro Yokoyama ◽

Hiroshi Funakubo ◽

...

Keyword(s):

Thin Films ◽

Rare Earth ◽

Lead Zirconate Titanate ◽

Ferroelectric Property ◽

Ferroelectric Properties ◽

Lead Zirconate ◽

Crystal Anisotropy ◽

Pzt Film ◽

Zirconate Titanate ◽

Ion Substitution

ABSTRACTRare-earth-substituted tetragonal lead zirconate titanate thin films were synthesized for improving the ferroelectric property of conventional lead zirconate titanate. Thin films of Pb1.00REx (Zr0.40Ti0.60)1-(3x /4)O3 (x = 0.02, RE = Y, Dy, Er and Yb) were deposited on (111)Pt/Ti/SiO2/(100)Si substrates by a chemical solution deposition (CSD). B-site substitution using rare-earth cations described above enhanced the crystal anisotropy, i.e., ratio of PZT lattice parameters c/a. Remanent polarization (Pr) of PZT film was enhanced by Y3+-, Dy3+- and Er3+-substitution from 20 μC/cm2 up to 26, 25 and 26 μC/cm2 respectively, while ion substitution using Yb3+ degraded the Pr value down to 16 μC/cm2. These films had similar coercive fields (Ec) of around 100 kV/cm. Improving the ferroelectric property of PZT film by rare-earth-substitution would be ascribed to the enhancement of the crystal anisotropy. We concluded that ion substitution using some rare-earth cations, such as Y3+, Dy3+ or Er3+, is one of promising technique for improving the ferroelectric property of PZT film.

Download Full-text

Effect of Bottom Electrodes on Structural and Electrical Properties of Laser Ablated SrBi2Ta2O9 Thin Films

MRS Proceedings ◽

10.1557/proc-688-c4.11.1 ◽

2001 ◽

Vol 688 ◽

Author(s):

Rasmi R. Das ◽

W. Pérez ◽

P. Bhattacharya ◽

Ram. S. Katiyar

Keyword(s):

Thin Films ◽

Barrier Height ◽

Ferroelectric Properties ◽

High Resistivity ◽

Emission Model ◽

X Ray Diffraction ◽

Oxide Electrodes ◽

Maximum Value ◽

Structural And Electrical Properties ◽

Raman Modes

AbstractWe have grown SrBi2Ta2O9 (SBT) thin films on various bottom electrodes such as Pt/TiO2/SiO2/Si (Pt) and LaNiO3/Pt/TiO2/SiO2/Si (LNO) substrates. The substrate temperature and oxygen pressure for the SBT film was maintained at 500 °C and 200 mTorr. As-grown films were post-annealed at a temperature of 800 °C. X-ray diffraction studies revealed that as-grown films were amorphous and crystallized to single phase after annealing. The difficulty of obtaining lowest Raman modes of SBT on platinized silicon substrate was overcome by using conducting oxide electrodes. Films grown on platinized silicon showed maximum value of remanent polarization (2Pr ∼ 21.5 μC/cm2) with coercive field (Ec) of ∼ 67 kV/cm. The degradation of ferroelectric properties of the films was observed with the introduction of 50 nm conducting LaNiO3 electrode at the interface of Pt and SBT film, which was attributed to high resistivity of the oxide electrode layers. Leakage current density was studied with the consideration of the Schottky emission model. The barrier height of the films grown on Pt and LNO were estimated to be 1.27 eV and 1.12 eV, respectively. The reduction of barrier height was attributed to the lower work function of the LNO electrode.

Download Full-text

Dependence of Ferroelectric Properties of SBT Based Capacitors on the Electrode Material

MRS Proceedings ◽

10.1557/proc-541-185 ◽

1998 ◽

Vol 541 ◽

Author(s):

S. Tirumala ◽

S. O. Ryu ◽

K. B. Lee ◽

R. Vedula ◽

S. B. Desu

Keyword(s):

Thin Films ◽

Electrode Material ◽

Electrode Materials ◽

Perovskite Phase ◽

Ferroelectric Properties ◽

Si Substrates ◽

Non Volatile Memory ◽

Metal Organic ◽

Sputter Deposited ◽

Memory Applications

AbstractThe effect of various electrode materials on the ferroelectric properties of SrBi2Ta2O9 (SBT) thin films has been investigated for non-volatile memory applications. Two sets of electrode structures, viz., Pt-Ir based and Pt-Rh based, were sputter deposited in-situ on Si substrates. SBT thin films were deposited on these electrodes using a metal-organic solution deposition technique followed by a post-deposition anneal at 750 °C in oxygen. Structural characterization revealed a polycrystalline nature with predominant perovskite phase in SBT thin films. Ferroelectric properties were studied in capacitor mode by depositing top electrodes, where the top electrode material is identical to that of the bottom electrode. Extensive analysis of the ferroelectric properties signify the important role played by the electrode material in establishing the device applicability is reported in this work.

Download Full-text

Fabrication of V-Substituted (Bi,M)4Ti3O12 [M = Lanthanoids] Thin Films by Chemical Solution Deposition Method

MRS Proceedings ◽

10.1557/proc-688-c2.3.1 ◽

2001 ◽

Vol 688 ◽

Cited By ~ 2

Author(s):

H. Uchida ◽

H. Yoshikawa ◽

I. Okada ◽

H. Matsuda ◽

T. Iijima ◽

...

Keyword(s):

Thin Films ◽

Chemical Solution Deposition ◽

Bismuth Titanate ◽

Ferroelectric Properties ◽

Ferroelectric Materials ◽

Processing Temperature ◽

Chemical Solution ◽

Si Substrate ◽

Solution Deposition ◽

Chemical Solution Deposition Method

AbstractBismuth titanate (Bi4Ti3O12; BIT) -based ferroelectric materials are proposed from the view of the “Site-engineering”, where the Bi-site ions are substituted by lanthanoid ions (La3+ and Nd3+) and Ti-site ions by other ions with higher charge valence (V5+). In the present study, influences of vanadium (V) - substitution for (Bi,M)4Ti3O12 thin films [M = lanthanoid] on the ferroelectric properties are evaluated. V-substituted (Bi,M)4Ti3O12 films have been fabricated using a chemical solution deposition (CSD) technique on the (111)Pt/Ti/SiO2/(100)Si substrate. Remnant polarization of (Bi,La)4Ti3O12 and (Bi,Nd)4Ti3O12 films has been improved by the V-substitution independent of the coercive field. The processing temperature of BLT and BNT films could also be lowered by the V-substitution.

Download Full-text