scholarly journals Preparation features and electrical properties of Na0.5Bi0.5TiO3 thin films

2020 ◽  
Vol 28 (1) ◽  
pp. 33-38
Author(s):  
T. V. Kruzina ◽  
S. A. Popov ◽  
Yu. N. Potapovich ◽  
S. I. Ryabtsev ◽  
A. S. Rutskiy

Some special features of Na0.5Bi0.5TiO3 (NBT) thin films preparation process and electrical properties of the films are presented. The NBT films were grown on both Pt/sitall and Pt/TiO2/SiO2/Si substrates by ex-situ method with high-frequency (13.56 MHz) magnetron deposition. Thermal treatment of the films was carried out in the temperature range 550°С – 700°С in air. Obtained X-ray diffraction data show that annealing at 700°C promotes crystallization of NBT films in ferroelectric perovskite phase with minor inclusions of pyrochlore phase. Dielectric hysteresis (P-E) loops in electric field of 90 kV/cm (50 Hz) and the current density-electric field (J-E) characteristics of the films are investigated. It is found that densities of leakage currents in weak fields depend on the film substrate and are significantly lower for the films deposited on the Pt/sitall structure (~6.9 10-10 A/cm2) in comparison with the films deposited on the Pt/TiO2/SiO2/Si structure (~10-6 A/cm2). The main mechanisms of leakage currents in thin NBT ferroelectric films and the role of structural defects in charge transfer process are discussed.

2008 ◽  
Vol 23 (2) ◽  
pp. 536-542 ◽  
Author(s):  
Phoi Chin Goh ◽  
Kui Yao ◽  
Zhong Chen

Ferroelectric thin films of the 0.1Pb(Ni1/3Nb2/3)O3–0.35Pb(Zn1/3Nb2/3)O3–0.15Pb (Mg1/3Nb2/3)O3–0.1PbZrO3–0.3PbTiO3 (PNN–PZN–PMN–PZ–PT) complex oxide system were prepared on Pt/Ti/SiO2/Si substrates using a polymer-modified sol-gel method followed by a rapid thermal annealing (RTA) process. It was found that the addition of excess NiO is effective in stabilizing the perovskite phase while suppressing the pyrochlore phase. The crystalline structure and morphology of the films with different amounts of access NiO were studied with x-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM), respectively. The electrical properties, including dielectric, ferroelectric, and piezoelectric, showed a significant improvement with excess NiO. The film sample with 3 mol% of excess NiO exhibited optimized electrical properties. Different parameters, including tolerance factors on the basis of ionic radii, electronegativity differences between cations and anions, and oxygen bond valences, were applied to analyze the stability of the perovskite phase with different amount of excess NiO. Analysis results indicated that only the bond-valence theory could explain the effect of excess NiO on the stability of the perovskite phase under the assumption that the excess Ni2+ entered the A sites of the perovskite structure.


1994 ◽  
Vol 361 ◽  
Author(s):  
S.D. Bernstein ◽  
T.Y. Wong ◽  
S.R. Collins ◽  
Yanina Kisler ◽  
R.W. Tustison

ABSTRACTFilms were deposited onto unheated, Ti/Pt coated Si substrates by reactive sputtering in an argon-oxygen atmosphere from a sintered PZT target, and subsequently crystallized at temperatures between 550 and 650 °C. Pt/PZT/Pt capacitors were formed by ion beam sputtering of top electrodes through a shadow mask. Electrical properties were found to depend on gas pressure during deposition. This effect is interpreted in terms of variations in film stoichiometry (particularly Pb content). Films with large excesses of Pb were found to exhibit high leakage currents and poor ferroelectric behavior, whereas films with lower excesses of Pb had low leakage currents, and good ferroelectric properties. Films with the largest Pb excess had a random orientation, while the film with the lowest Pb excess had a preferred (111) orientation. With 550 °C crystallization temperatures the films consist of a mixture of ferroelectric perovskite phase and either PZT pyrochlore or PbO. At higher crystallization temperatures no pyrochlore is detected.


2018 ◽  
Vol 26 (1) ◽  
pp. 53-56
Author(s):  
T. V. Kruzina ◽  
S. A. Popov ◽  
Yu. N. Potapovich ◽  
A. S. Rutskyi

Na0.5Bi0.5TiO thin films were grown on heated to 200°С Pt/TiO2/SiO2/Si substrates by ex-situ method with high-frequency (13.56 MHz) magnetron deposition. Thermal treatment of the films was carried out at 650°С, 700°С and 800°С. X-ray diffraction investigations showed the films were poly-crystalline and contained additional phase. In the films annealed at 700°C two dominating conduction mechanisms were observed: ohmic at the fields Е < 8 kV/cm and Schottky emission in the field range of 30 – 70 kV/cm. It is also observed that the increase of the film annealing temperature to 800°С leads to the increase of leakage currents. It is assumed that high values of the leakage currents were attributed to the presence of both structure defects and additional unknown phase.


2001 ◽  
Vol 688 ◽  
Author(s):  
Apurba Laha ◽  
S. Saha ◽  
S. B. Krupanidhi

AbstractA study was done on pulsed laser deposited relaxor ferroelectric thin films of 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) deposited on platinized silicon substrates with template layers to observe the influence of the template layers on physical and electrical properties. Initial results, showed that perovskite phase (80% by volume) was obtained through proper selection of the processing conditions on Pt/Ti/SiO2/Si substrates. The films were grown at 300°C and then annealed in a rapid thermal annealing furnace in the temperature range of 750-850°C to induce crystallization. Comparison of the films annealed at different temperatures revealed a change in crystallinity, perovskite phase formation and grain size. These results were further used to improve the quality of the perovskite PMN-PT phase by inserting thin layers of TiO2 on the Pt substrate. These resulted in an increase in perovskite phase in the films even at lower annealing temperatures. Dielectric studies on the PMN-PT films show very high values of dielectric constant (1300) at room temperature, which further improved with the insertion of the template seed layer. The relaxor properties of the PMN-PT were correlated with Vogel-Fulcher theory to determine the actual nature of the relaxation process.


1998 ◽  
Vol 541 ◽  
Author(s):  
S. Tirumala ◽  
S. O. Ryu ◽  
K. B. Lee ◽  
R. Vedula ◽  
S. B. Desu

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.


2006 ◽  
Vol 21 (2) ◽  
pp. 505-511 ◽  
Author(s):  
Lili Hu ◽  
Junlan Wang ◽  
Zijian Li ◽  
Shuang Li ◽  
Yushan Yan

Nanoporous silica zeolite thin films are promising candidates for future generation low-dielectric constant (low-k) materials. During the integration with metal interconnects, residual stresses resulting from the packaging processes may cause the low-k thin films to fracture or delaminate from the substrates. To achieve high-quality low-k zeolite thin films, it is important to carefully evaluate their adhesion performance. In this paper, a previously reported laser spallation technique is modified to investigate the interfacial adhesion of zeolite thin film-Si substrate interfaces fabricated using three different methods: spin-on, seeded growth, and in situ growth. The experimental results reported here show that seeded growth generates films with the highest measured adhesion strength (801 ± 68 MPa), followed by the in situ growth (324 ± 17 MPa), then by the spin-on (111 ± 29 MPa). The influence of the deposition method on film–substrate adhesion is discussed. This is the first time that the interfacial strength of zeolite thin films-Si substrates has been quantitatively evaluated. This paper is of great significance for the future applications of low-k zeolite thin film materials.


2010 ◽  
Vol 434-435 ◽  
pp. 263-266
Author(s):  
Chien Chen Diao ◽  
Chia Ching Wu ◽  
Cheng Fu Yang ◽  
Chao Chin Chan

In this study, 0.95 (Na0.5Bi0.5)TiO3-0.05 BaTiO3 + 1 wt% Bi2O3 (NBT-BT3) composition sintered at 1200oC for 2h is used as target to deposit the NBT-BT3 thin films. The excess 1wt% Bi2O3 is used to compensate the vaporization of Bi2O3 during the deposition process. Ferroelectric NBT-BT3 thin films are deposited on SiO2/Si and Pt/Ti/SiO2/Si substrates using RF magnetron sputter method using the ceramic target fabricated by ourselves. After depositing under the optimal parameters, the thin films are then heated by a conventional thermal annealing (CFA) process conducted in air at temperatures ranging from 600- 800oC for 60min. The morphologies of NBT- BT3 thin films are observed using SEM the crystalline structures of NBT-BT3 thin films are investigated using XRD patterns. The large memory window and stable leakage current density examination reveals that NBT-BT3 thin films annealed on 600oC are better than other thin films under different CTA temperatures. Finally, the top view and cross-sectional images of SEM, memory windows, leakage currents and polarization characteristics of NBT-BT3 thin films are also well developed.


2014 ◽  
Vol 633 ◽  
pp. 378-381
Author(s):  
Bei Li ◽  
X.B. Liu ◽  
M. Chen ◽  
X.A. Mei

Dy-doped Bi4Ti3O12 thin films were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition technique, and the structures and electrical properties of the films were investigated. XRD results indicated that all of Bi4-xDyxTi3O12 films consisted of single phase of a bismuth-layered structure with well-developed rod-like grains. The remanent polarization ( Pr ) and coercive field (Ec) of the Bi4-xDyxTi3O12 Film with x=0.75 were 25μC/cm2 and 85KV/cm , respectively.


2001 ◽  
Vol 685 ◽  
Author(s):  
Won-Jae Lee ◽  
Chang-Ho Shin ◽  
In-Kyu You ◽  
Il-Suk Yang ◽  
Sang-Ouk Ryu ◽  
...  

AbstractThe SrTa2O6 (STO) thin films were prepared by plasma enhanced atomic layer deposition (PEALD) with alternating supply of reactant sources, Sr[Ta(C2H5O)5(C4H10NO)]2 {Strontium bis-[tantalum penta-ethoxide dimethyllaminoethoxide]; Sr(Ta(OEt)5▪dmae)2} and O2plasma. It was observed that the uniform and conformal STO thin films were successfully deposited using PEALD and the film thickness per cycle was saturated at about 0.8 nm at 300°C. Electrical properties of SrTa2O6 (STO) thin films prepared on Pt/SiO2/Si substrates with annealing temperatures have been investigated. While the grain size and dielectric constant of STO films increased with increasing annealing temperature, the leakage current characteristics of STO films slightly deteriorated. The leakage current density of a 40nm-STO film was about 5×10−8A/cm2 at 3V.


1996 ◽  
Vol 433 ◽  
Author(s):  
T. B. Wu ◽  
J. M. Wu ◽  
C. M. Wu ◽  
M. J. Shyu ◽  
M. S. Chen ◽  
...  

AbstractHighly (100)-textured thin film of metallic LaNiO3 (LNO) was grown on the Pt/Ti/SiO2/Si substrates by rf magnetron sputtering at ˜300°C, which was used as a bottom electrode to prepare highly (100)-textured ferroelectric films. Examples on the deposition of PbTiO3, (Pbl−xLax)TiO3, Pb(Zr0.53Ti0.47)O3, Pb[(Mg1/3Nb2/3)1−xTix]O3, and (Ba1−xSrx)TiO3 thin films by rf magnetron sputtering or sol-gel method are shown. A reduction of temperature for perovskite phase formation can be achieved, especially for those difficult to crystallize. The surface roughness of the ferroelectric films is also improved as compared to that of films deposited on conventional Pt electrode. Although the electrical properties of the ferroelectric films are affected by the out-diffusion of LNO when a higher temperature was used in the preparation of the films, under an appropriate processing condition, the highly (100)-textured films can have satisfactory electrical characteristics for application. Moreover, the polarization-fatigue property can be also improved by the use of LNO electrode.


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