Ferroelectric Property of Ion Beam Enhanced Deposited Lithium Tantalate Thin Film

2011 ◽  
Vol 335-336 ◽  
pp. 1418-1423
Author(s):  
De Yin Zhang ◽  
Wei Qian ◽  
Kun Li ◽  
Jian Sheng Xie

The Ion Beam Enhanced Deposited (IBED) lithium tantalate (LiTaO3) thin film samples with Al/LiTaO3/Pt electrode structure were prepared on the Pt/Ti/SiO2/Si(100) and SiO2/Si(100) substrate respectively. The crystallization, surface morphology, ferroelectric property, and fatigue property of the prepared samples with the different annealed processes were investigated. The XRD measured results show that the prepared samples have the polycrystal structure of LiTaO3 with the preferred orientation of <012> and <104> located at the 2θ of 23.60 and 32.70 respectively. The SEM morphology analysis reveals the prepared film annealed at 550°C is uniform, smooth and crack-free on the surface and cross section. The ferroelectric property measured results show that the remanent polarization Pr of the samples annealed at different temperature almost increase with the electric field intensity stronger. The leakage current makes the hysteresis loop of the samples subjected to a strong measured electric filed difficult to appear the same saturation hysteresis loop as the single-crystal LiTaO3. The prepared samples annealed at 550°C have a Pr value of 11.5μC/cm2 when subjected to the electrical field of 400kV/cm. The breakdown voltage of the 587nm thick thin film sample is high as to 680 kV/cm. The fatigue property measured results show only 15.17% Pr drop of the prepared films annealed at 550°C appear after 5×1010 cycles polarized by the 10MHz sinusoidal signal with the peak-to-peak amplitude of 10 Volt. The ferroelectric properties of the prepared films meet the practical application requirements of charge response measurement of the LiTaO3 infrared detector owe to the Pr of the prepared films annealed at different temperature large beyond 10μC/cm2 when the prepared films subjected to a strong electric filed larger than 400 kV/cm. The experimental results also show that the surface morphology, the ferroelectric and fatigue properties of the IBED LiTaO3 thin films are significant better than those of the Sol-Gel derived LiTaO3 thin films.

1999 ◽  
Vol 596 ◽  
Author(s):  
Tingkai Li ◽  
Sheng Teng Hsu ◽  
Yufei Gao ◽  
Mark Engelhard

AbstractThree kinds of oriented electrodes of Pt, Ir and Pt/Ir electrodes were prepared using electron beam evaporation techniques for deposition of PZT thin films. An oxide MOCVD reactor with liquid delivery system was used for the growth of PZT thin films. [Pb(thd)2], Zr(TMHD)4 and Ti(IPO)4 were dissolved in a mixed solvent of tetrahydrofuran or butyl ether, isopropanol and tetraglyme to form a precursor source. The deposition temperature and pressure were 500 - 650°C and 5 - 10 Torr, respectively. The experimental results showed PZT thin film deposited on various electrodes had different phase formation, microstructure and ferroelectric property. The X-ray patterns showed the perovskite phase of PZT was formed on both Ir and Pt/Ir electrodes at 550°C. The grain size of the PZT thin film increases after a further, higher temperature annealing. The as-deposited PZT thin film on Pt electrode exhibits pyrochlore phase at 550°C. The phase is transformed to perovskite phase after 650°C annealing. The experimental results also indicated that the MOCVD PZT thin film on Pt/Ir exhibits better ferroelectric and electrical properties compared to those deposited on Pt and Ir electrodes. A 300 nm thick PZT thin film on Pt/Ir electrode has a square, well saturated, and symmetrical hysteresis loop with 2Pr value of 40 μC/cm2 and 2Ec of 73 kV/cm at an applied voltage of 5 V. The hysteresis loop of the PZT thin film is almost saturated at 2 V. The leakage current of the film is 6.16 × 10−7 A/cm2 at 100 KV/cm. The electrode effects on ferroelectric properties of PZT thin films also have been investigated.


2011 ◽  
Vol 117-119 ◽  
pp. 840-844
Author(s):  
Xu Yong Wu ◽  
De Yin Zhang ◽  
Kun Li

The novel lithium enriched lithium tantalate (LiTaO3) targets were papered by employing the sol-gel process and the high temperature sintered process. The sol of LiTaO3 was firstly prepared through reacting lithium ethoxide with tantalum ethoxide. The LiTaO3 powder was fabricated by presintered LiTaO3 dry gel 4 hour, at 800°C. The 11cm13cm1cm lithium enriched LiTaO3 target samples were prepared by sintered the pressed LiTaO3 powder billet 4 hour in the 850°C muffle furnace. The density of the 5% overdose lithium enriched LiTaO3 target is measured 5.96g/cm3. The XRD measured results show that the ion beam enhanced deposited (IBED) thin film samples using the prepared 5% overdose lithium enriched LiTaO3 target have the polycrystal structure of LiTaO3, but there has remanent Ta2O5 existed in the IBED thin film samples. The main reason for the remanent Ta2O5 growth was due to the stoichiometric proportion mismatch between Li and Ta in the IBED thin film samples during the high temperature annealed process, which caused the lithium oxide evaporation loss from the IBED thin film samples and made the proportion of Ta2O5 increase. After multipule repeated target prepared experiments, the 8.76% overdose lithium enriched LiTaO3 target is suitable for fabricating the 550°C annealed IBED LiTaO3 thin film. After the repeated process experiments, the suitable deposited process parameters of the IBED-C600M instrument for the 8.76% overdose lithium enriched LiTaO3 target were obtained. The SEM micrographs of the 550°C annealed IBED LiTaO3 thin films prepared by the 8.76% overdose lithium enriched LiTaO3 target reveal the prepared thin films are uniform, smooth and crack-free on the surface, and the perfect adhesion between the thin film and the substrate. The successfully fabricated LiTaO3 thin film samples verify the prepared processes of novel LiTaO3 sputtering target are effective.


2013 ◽  
Vol 832 ◽  
pp. 724-727 ◽  
Author(s):  
Mohamad Hafiz Mohd Wahid ◽  
Rozana Mohd Dahan ◽  
Siti Zaleha Sa'ad ◽  
Adillah Nurashikin Arshad ◽  
Muhamad Naiman Sarip ◽  
...  

The different morphology of 250 nm PVDF-TrFE (70:30 mol%) thin films were observed in relation to its ferroelectricity. The annealing temperatures were varied from solvent evaporation (Ts), Curies transition (Tc), up to melting temperature (Tm). It was found that the annealing process promoted the development of elongated crystallite structure also known as ferroelectric crystal, which significantly improved the ferroelectric properties of PVDF-TrFE (70:30 mol%) thin films. However, the presence of nanoscale separations on the thin film annealed over Tm (AN160) suggested high possibility of defects, and hence a reduction in ferroelectric properties of thin films.


2011 ◽  
Vol 1292 ◽  
Author(s):  
Seiji Nakashima ◽  
Yosuke Tsujita ◽  
Hironori Fujisawa ◽  
Jung Min Park ◽  
Takeshi Kanashima ◽  
...  

ABSTRACTBiFeO3 (BFO) thin films have been deposited on SrRuO3/SrTiO3 (001) substrate by using ion beam sputtering process. At low oxygen partial pressure of 11 m Pa, rhombohedral and large c/a mixed phase thin film have been obtained in spite of rhombohedral BFO single phase formation at high oxygen partial pressure of 73 mPa. From wide area 2θ-Ψ mappings, diffraction peaks from large c/a phase BFO thin film were obtained with the same extinction rule as those of rhombohedral BFO. Reciprocal space mappings around BFO (003) and BFO (103) spots indicate that lattice parameters of large c/a phase BFO were a = 0.381 nm and c = 0.461 nm (c/a =1.22), respectively. Moreover ferroelectric domain switching could be observed in both of rhombohedral BFO and mixed phase BFO thin films.


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.


2010 ◽  
Vol 17 (05n06) ◽  
pp. 445-449 ◽  
Author(s):  
SUHUA FAN ◽  
QUANDE CHE ◽  
FENGQING ZHANG

The (100)-oriented Ca0.4Sr0.6Bi4Ti4O15(C0.4S0.6BTi ) thin film was successfully prepared by a sol-gel method on Pt/Ti/SiO2/Si substrate. The orientation and formation of thin films under different annealing schedules were studied using XRD and SEM. XRD analysis indicated that (100)-oriented C0.4S0.6BTi thin film with degree of orientation of I(200)/I(119) = 1.60 was prepared by preannealing the film at 400°C for 3 min followed by rapid thermal annealing at 800°C for 5 min. SEM analysis further indicated that the (100)-oriented C0.4S0.6BTi thin film with a thickness of about 800 nm was mainly composed of equiaxed grains. The remanent polarization and coercive field of the film were 16.1 μC/cm2 and 85 kV/cm, respectively.


2011 ◽  
Vol 13 ◽  
pp. 87-92 ◽  
Author(s):  
M.S.P Sarah ◽  
F.S. Zahid ◽  
M.Z. Musa ◽  
U.M. Noor ◽  
Z. Shaameri ◽  
...  

The photoconductivity of a nanocomposite MEH-PPV:TiO2 thin film is investigated. The nanocomposite MEH-PPV:TiO2 thin film was deposited on a glass substrate by spin coating technique. The composition of the TiO2 powder was varied from 5 wt% to 20 wt% (with 5 wt% interval). The concentration of the MEH-PPV is given by 1 mg/1 ml. The current voltage characteristics were measured in dark and under illumination. The photoconductivity showed increment in value as the composition of the TiO2 is raised in the polymer based solution. The absorption showed augmentation as the amount of TiO2 is increased. The escalation of the current voltage is then supported by the results of surface morphology.


1995 ◽  
Vol 388 ◽  
Author(s):  
Yoshihisa Watanabe ◽  
Yoshikazu Nakamura ◽  
Shigekazu Hirayama ◽  
Yuusaku Naota

AbstractAluminum nitride (AlN) thin films have been synthesized by ion-beam assisted deposition method. Film deposition has been performed on the substrates of silicon single crystal, soda-lime glass and alumin A. the influence of the substrate roughness on the film roughness is studied. the substrate temperature has been kept at room temperature and 473K and the kinetic energy of the incident nitrogen ion beam and the deposition rate have been fixed to 0.5 keV and 0.07 nm/s, respectively. the microstructure of the synthesized films has been examined by X-ray diffraction (XRD) and the surface morphology has been observed by atomic force microscopy(AFM). IN the XRD patterns of films synthesized at both room temperature and 473K, the diffraction line indicating the alN (10*0) can be discerned and the broad peak composed of two lines indicating the a1N (00*2) and a1N (10*1) planes is also observed. aFM observations for 100 nm films reveal that (1) the surface of the films synthesized on the silicon single crystal and soda-lime glass substrates is uniform and smooth on the nanometer scale, (2) the average roughness of the films synthesized on the alumina substrate is similar to that of the substrate, suggesting the evaluation of the average roughness of the film itself is difficult in the case of the rough substrate, and (3) the average roughness increases with increasing the substrate temperature.


2021 ◽  
Vol 8 ◽  
Author(s):  
Jinyu Ruan ◽  
Chao Yin ◽  
Tiandong Zhang ◽  
Hao Pan

Ferroelectric multilayer films attract great attention for a wide variation of applications. The synergistic effect by combining different functional layers induces distinctive electrical properties. In this study, ferroelectric BaZr0.2Ti0.8O3/PbZr0.52Ti0.48O3/BaZr0.2Ti0.8O3 (BZT/PZT/BZT) multilayer thin films are designed and fabricated by using the magnetron sputtering method, and a LaNiO3 (LNO) seed layer is introduced. The microstructures and electrical properties of the BZT/PZT/BZT films with and without the LNO seed layer are systematically studied. The results show that the BZT/PZT/BZT/LNO thin film exhibits much lower surface roughness and a preferred (100)-orientation growth, with the growth template and tensile stress provided by the LNO layer. Moreover, an enhanced dielectric constant, decreased dielectric loss, and improved ferroelectric properties are achieved in BZT/PZT/BZT/LNO thin films. This work reveals that the seed layer can play an important role in improving the microstructure and properties of ferroelectric multilayer films.


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