Preparation and ferroelectric properties of mixed composition layered lead zirconate titanate thin films for nonvolatile memory applications

1999 ◽  
Vol 14 (6) ◽  
pp. 2476-2483 ◽  
Author(s):  
Seung-Hyun Kim ◽  
Dong-Joo Kim ◽  
S. K. Streiffer ◽  
A. I. Kingon

Mixed composition layered lead zirconate titanate (PZT) films sZr/Ti ratio = 30/70 + 65/35d with stoichiometric lead containing PZT thin layer at the film/electrode interface were successfully fabricated by a modified chemical solution deposition method. These modified PZT thin films are highly (111) textured, and have square-shaped P-E hysteresis loops with large remanent polarization and low coercive field, as well as low saturation voltage. In addition, these films show good fatigue and imprint behavior with Pt electrodes; the retained polarization of the modified film was above 50% after fatigue testing to 109 cycles, and the thermally induced voltage shifts (ΔV) were 0.51 V after heating at 150 °C for 4410 s, two times lower than for films without a stoichiometric thin layer.

2004 ◽  
Vol 830 ◽  
Author(s):  
Hiroshi Nakaki ◽  
Hiroshi Uchida ◽  
Shoji Okamoto ◽  
Shintaro Yokoyama ◽  
Hiroshi Funakubo ◽  
...  

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.


2006 ◽  
Vol 16 (4) ◽  
pp. 425-430 ◽  
Author(s):  
Fransiska Cecilia Kartawidjaja ◽  
Zhaohui Zhou ◽  
John Wang

1991 ◽  
Vol 69 (3-4) ◽  
pp. 260-264 ◽  
Author(s):  
E. M. Griswold ◽  
M. Sayer ◽  
D. T. Amm ◽  
I. D. Calder

Ferroelectric thin films have recently proven viable for nonvolatile memory applications in semiconductor technology. Current research is focused on the development of processing technologies and deposition on metallized semiconductor substrates. In this study, niobium-doped lead zirconate titanate thin films were prepared by a dc magnetron-sputtering technique using a multielement metal target. Films were deposited on indium tin oxide coated glass and on metallizations on silicon substrates. The crystallographic structure and surface morphology of the films was examined by scanning electron microscopy and X-ray diffraction as a function of processing variables such as sputtering pressure, film thickness, and niobium content. Electrical characterization of the films is discussed in terms of ferroelectric hysteresis and polarization properties. Improved ferroelectric properties are achieved through a densified structure resulting from niobium-doping.


2007 ◽  
Vol 14 (02) ◽  
pp. 229-234
Author(s):  
SARAWUT THOUNTOM ◽  
MANOCH NAKSATA ◽  
KENNETH MACKENZIE ◽  
TAWEE TUNKASIRI

Lead zirconate titanate (PZT) films with compositions near the morphotropic phase boundary were fabricated on Pt (111)/ Ti / SiO 2/ Si (100) using the triol sol–gel method. The effect of the pre-heating temperature on the phase transformations, microstructures, electrical properties, and ferroelectric properties of the PZT thin films was investigated. Randomly oriented PZT thin films pre-heated at 400°C for 10 min and annealed at 600°C for 30 min showed well-defined ferroelectric hysteresis loops with a remnant polarization of 26.57 μC/cm2 and a coercive field of 115.42 kV/cm. The dielectric constant and dielectric loss of the PZT films were 621 and 0.0395, respectively. The microstructures of the thin films are dense, crack-free, and homogeneous with fine grains about 15–20 nm in size.


2006 ◽  
Vol 928 ◽  
Author(s):  
Sharath Sriram ◽  
Madhu Bhaskaran ◽  
Anthony Stephen Holland ◽  
Geoffrey K Reeves

ABSTRACTStudies on strontium-doped lead zirconate titanate (PSZT) have been reported for its high piezoelectric and ferroelectric properties. For PSZT to exhibit pronounced piezoelectric behaviour it must have a crystalline grain structure (perovskite orientation). This paper is a study of the deposition of PSZT thin films by RF magnetron sputtering and the effect of cooling rate, after deposition at temperatures between 500 °C and 700 °C. X-Ray Diffraction (XRD) results are used to show how a cooling rate of 5 °C/min increases the degree of perovskite orientation in sputtered films, when compared to a cooling rate of 15 °C/min. The absence of significant shifts in the positions of diffraction peak patterns in XRD results are used to demonstrate low stress in the deposited films. Atomic Force Microscope (AFM) imaging is used to show the crystalline nature of the PSZT thin films.


1991 ◽  
Vol 30 (Part 1, No. 9B) ◽  
pp. 2167-2169 ◽  
Author(s):  
Hideo Kidoh ◽  
Toshio Ogawa ◽  
Hideyuki Yashima ◽  
Akiharu Morimoto ◽  
Tatsuo Shimizu

2002 ◽  
Vol 17 (4) ◽  
pp. 871-878 ◽  
Author(s):  
Timothy J. Boyle ◽  
Paul G. Clem ◽  
Bruce A. Tuttle ◽  
Geoffrey L. Brennecka ◽  
Jeffrey T. Dawley ◽  
...  

Lanthanide (Ln) doping of lead zirconate titanate (PLnZT 4/30/70) thin films was conducted to investigate effects on structural and electrical properties. Films were spin-coat deposited from precursor solutions made using a previously reported “basic route to PZT” chemistry. The remanent polarization (Pr), dielectric constant (ε), dielectric loss (tan δ), and lattice parameter values were obtained for each of the doped PLnZT films. Films doped with amphoteric cations (Tb, Dy, Y, and Ho) displayed high Pr values, square hysteresis loops, and enhanced fatigue resistance. Smaller radius Ln-doped films display an increased tendency toward (100) orientation in otherwise (111)-oriented films.


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