Control of Grain Size of Pb(Zr,Ti)O3 Thin Films by MOCVD and the Effect of Size on the Electrical Properties

1998 ◽  
Vol 541 ◽  
Author(s):  
H. Fujisawa ◽  
S. Nakashima ◽  
M. Shimizu ◽  
H. Niu

AbstractThe grain size of MOCVD-Pb(Zr,Ti)O3 (PZT) thin films was successfully controlled by changing the grain size of Ir bottom electrodes and by changing the growth rate of PZT films. In Ir/PZT/Ir/SiO2/Si capacitors, the grain size of PZT thin films increased from 120 to 240nm as the grain size of bottom Ir electrodes increased from 50 to 200nm. The dielectric constants of PZT thin films increased from 760 to 1440 as the grain size increased from 120 to 240nm. Remanent polarization increased and coercive field decreased as the grain size increased. This dependence of electrical properties on the grain size coincided with that of ceramics.

1994 ◽  
Vol 361 ◽  
Author(s):  
Wan In Lee ◽  
J.K. Lee ◽  
Elsub Chung ◽  
C.W. Chung ◽  
I.K. Yoo ◽  
...  

ABSTRACTPZT (Zr/Ti = 53/47), PNZT (4% Nb doped PZT), PSZT (2% Sc doped PZT), and PSNZT (1% Sc and 1% Nb doped PZT) thin films were prepared by a sol-gel process. They were characterized by XRD, SEM and TEM. Both crystallographic orientation and grain size of PZT films can be changed by doping. Pt/PZT/Pt capacitors were fabricated for the measurement of ferroelectric properties. By doping with both Sc and Nb, the fatigue performance of the PZT films was considerably improved and the coercive field was decreased, while the remanent polarization was not changed. In addition, the effect of dopants on the leakage current level of PZT films was studied.


2008 ◽  
Vol 368-372 ◽  
pp. 1814-1816
Author(s):  
Dan Xie ◽  
Zhi Gang Zhang ◽  
Tian Ling Ren ◽  
Li Tian Liu

{0.75SrBi2Ta2O9-0.25Bi3TiTaO9}(SBT-BTT) thin films were prepared by the modified metalorganic solution deposition (MOSD) technique. The microstructure and ferroelectric properties of SBTBTT thin films were studied. The SBT-BTT thin films were produced at 750°C. The grain size and surface roughness of SBT-BTT films showed significant enhancement with an increase in annealing temperatures. It is found that SBT-BTT thin films have good ferroelectric properties. The measured remanent polarization values for SBT-BTT, SBT and BTT capacitors were 15, 7.5 and 4.8μC/cm2, respectively. The coercive field for SBT-BTT capacitors was 50kV/cm. More importantly, the polarization of SBT-BTT capacitors only decreased 5% after 1011 switching cycles at a frequency of 1MHz.


2005 ◽  
Vol 902 ◽  
Author(s):  
Sushil Kumar Singh ◽  
Hiroshi Ishiwara

AbstractMn-doped Bi3.25La0.75Ti3O12 (BLT) thin films were fabricated by depositing sol-gel solutions on Pt/Ti/SiO2/Si <100> substrates. The surface morphology and ferroelectric properties of Mn-doped BLT films depend upon the orientation of the films. Small amount of Mn-doping in BLT films influences the ferroelectric properties of the films, that is, it enhances the remanent polarization and reduces the coercive field. The 1% Mn-doped BLT films show enhanced remanent polarization and reduced the coercive field by about 22%. To the contrary, Mn-doping more than 1% decreases polarization gradually. Mn-doping significantly improves the fatigue resistance of BLT films. The reduced polarization in the 3.3% Mn-doped thin film recovers during switching cycles higher than 5 × 105. Under high switching field, the probability of field-assisted unpinning of domains is expected to be high and this may be the main cause for increase in polarization after 5 × 105 in the 3.3% Mn-doped BLT film.


1995 ◽  
Vol 415 ◽  
Author(s):  
T. Ami ◽  
K. Hironaka ◽  
C. Isobel ◽  
N. Nagel ◽  
M. Sugiyama ◽  
...  

ABSTRACTFerroelectric Bi2 SrTa2 O9 thin films were successfully prepared by liquid delivery MOCVD, and structural and electrical properties were investigated. As-deposited films showed sharp distinct peaks, which were indexed assuming a fluorite-type structure. These precursors were transformed to bismuth-layered structures by annealing at 800 °C in flowing oxygen. Reasonable ferroelectric properties were observed in a film with 170 nm-thickness. Remanent polarization and coercive field were estimated to be 5.2 μC/cm2 and 52 kV/cm, respectively, at 5V.


2004 ◽  
Vol 449-452 ◽  
pp. 477-480
Author(s):  
J.H. Choi ◽  
Tae Sung Oh

Ferroelectric characteristics of the 400 nm-thick SrxBi2.4Ta2O9(0.7≤x≤1.3) thin films processed by metalorganic decomposition were investigated, and electrical properties of the Pt/Sr0.85Bi2.4Ta2O9/TiO2/Si structure prepared using TiO2 buffer layer were characterized. The Sr-deficient SrxBi2.4Ta2O9 films exhibited well-developed ferroelectric hysteresis curves compared to those of the Sr-excess films. The Sr0.85Bi2.4Ta2O9 film exhibited optimum ferroelectric properties, such as high remanent polarization and low leakage current density, among SrxBi2.4Ta2O9 films. A memory window of the Pt/SrxBi2.4Ta2O9/TiO2/Si structure was dependent upon the coercive field of the SrxBi2.4Ta2O9 film, and the Pt/SrxBi2.4Ta2O9/TiO2/Si exhibited a maximum memory window of 1.3 V at the sweeping voltage of ±5 V.


2021 ◽  
Author(s):  
jie jiang ◽  
Lei Liu ◽  
Kuo Ouyang ◽  
Zhouyu Chen ◽  
Shengtao Mo ◽  
...  

Abstract With its excellent ferroelectric properties such as large dielectric constant and large remanent polarization, PZT thin films are extensively used in micro-sensors and other devices. In this study, the sol-gel process was used to fabricate Pb(Zr0.52Ti0.48)O3 thin films with Pb(ZrxTi1−x)O3 seed islands. The experimental consequences demonstrate that all the Pb(Zr0.52Ti0.48)O3 thin films with Pb(ZrxTi1−x)O3 seeds show pure perovskite phase with no other impurity phases, and the electrical properties of Pb(Zr0.52Ti0.48)O3 thin films modified by Pb(ZrxTi1−x)O3 seed islands with different Zr/Ti ratios are improved, such as remanent polarization increased, dielectric properties increased, coercive electric field decreased, leakage current density decreased, etc. In particular, the electrical properties of the Pb(Zr0.52Ti0.48)O3 thin films with Pb(ZrxTi1−x)O3 seed islands are the most optimal when the x is 0.52. This paper provides a new technique for optimizing the electrical properties of PZT thin films, which is of great significance for breaking through the bottleneck of the development of ferroelectric memory.


2007 ◽  
Vol 121-123 ◽  
pp. 195-200 ◽  
Author(s):  
Jiu Peng Zhao ◽  
C.Y. Juan ◽  
Liang Sheng Qiang

In this work, PZT (Zr/Ti=52/48) thin films have been prepared using aqueous organic gel method. The desired metal cations are chelated in a solution using citric acid and ethylenediaminetertraacetic acid (EDTA) as the chelating agents. The thermal decompostion of the metal carboxylate precursors gels have been studied by TG/DTA and the products derived from calcinations of the gels at different temperatures have been characterized by XRD and SEM. By heat-treatment at 650°C for 2h, PZT thin films with smooth and crack-free surface could be achieved. The thickness of each layer was 50nm. Electric properties measurement indicated that the PZT films demonstrated a ferroelectric hysteresis loop. The remanent polarization(Pr) and coercive field (Ec) were 20.7μC/cm2 and 75.5kV/cm, respectively. The dielectric constant and the dielectric loss at 100 kHz of the films were 930 and 0.045, respectively.


1992 ◽  
Vol 271 ◽  
Author(s):  
Yuhuan Xu ◽  
Chih-Hsing Cheng ◽  
Ren Xu ◽  
John D. Mackenzie

ABSTRACTPb(ZrxTi1−x)O3 (PZT) solutions were prepared by reacting lead 2-ethylhexanoate with titanium n-propoxide and zirconium n-propoxide. Films were deposited on several kinds of metal substrate by dip-coating. Crystalline PZT films and amorphous PZT films were heat-treated for 1 hour at 650°C and at 400°C, respectively. Electrical properties including dielectric, pyroelectric and ferroelectric properties of both crystalline and amorphous PZT films were measured and compared. The amorphous PZT thin films exhibited ferroelectric-like behaviors.


2001 ◽  
Vol 688 ◽  
Author(s):  
Jinrong Cheng ◽  
Wenyi Zhu ◽  
Nan Li ◽  
L.Eric Cross

AbstractPZT thin films of different thicknesses and Zr/Ti ratios of 60/40, 52/48 and 45/55 were coated onto platinized silicon substrates by using 2 methoxyethanol (2-MOE) based sol-gel spinon technique and crystallized with a rapid thermal annealing (RTA) process. XRD analysis revealed that thin PZT films exhibit random texture, while the thicker ones exhibit (100) texture, which was independent of composition. Dielectric constants and dissipation factors of PZT thin films were measured at elevated temperatures and as a function of frequency. For films with a thickness of ∼ 4 μm, the Curie points are at 350, 375 and 422°C for Zr/Ti ratios of 60/40, 52/48 and 45/55, respectively. All these films exhibit a high remnant polarization. A remnant polarization of 35 μC/cm2 had been achieved for the 60/40 films. No enhancement of the dielectric constant was observed in films with a composition close to MPB. The higher dielectric constant observed in films with the highest Zr content was explained by the concept of domain engineering.


1999 ◽  
Vol 14 (3) ◽  
pp. 1018-1025 ◽  
Author(s):  
Seung-Hyun Kim ◽  
J. G. Hong ◽  
S. K. Streiffer ◽  
Angus I. Kingon

We have investigated the effect of RuO2 (10, 30, 50 nm)/Pt layered hybrid bottom electrode structure and film composition on the leakage and fatigue properties of chemical solution derived Pb(ZrxTi1−x)O3 (PZT) thin films. It was observed that the use of high Ti content (Zr: Ti = 30: 70) films with control of excess PbO at the thin RuO2 (10 nm)/Pt bottom electrode surface reduced leakage current and showed good fatigue properties with high remanent polarization compared to the use of high Zr films (Zr: Ti = 50: 50) or thicker RuO2 (30, 50 nm)/Pt bottom electrodes. Typical P-E hysteresis behavior of PZT films was observed even at an applied voltage of 3 V, demonstrating greatly improved remanence and coercivity. Fatigue and breakdown characteristics of these modified PZT thin films (Zr: Ti = 30: 70) on RuO2 (10 nm)/Pt, measured at 5 V, showed stable behavior, and less than 15% fatigue degradation was observed up to 1010 cycles.


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