bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructural and Electrical Properties of Ferroelectric Capacitors with Pt/RuO2 Hybrid Electrodes
Authors: Al-Shareef H.N. , Chen Y.L. , Auciello O. , Kingon A.I. 
Published: April 2011

ABSTRACTThin films of pb(Zr0.53Ti0.47)O3 (PZT) grown in our laboratory on RuO2 electrodes by the sol-gel process are characterized by high leakage currents and by the presence of a pyrochlore-type second phase. We have used a thin Pt interlayer between the PZT film and RuO2 bottom electrode to produce RuO2/PZT/100ÅPt/RuO2/SiO2/Si capacitor structures. It is found that use of such a Pt interlayer significantly reduces or eliminates the second phase in the PZT films, and lowers their leakage currents by more than four orders of magnitude. At the same time, the excellent resistance to polarization fatigue characteristic of the RuO2/PZT/RuO2 capacitors is maintained. The microstructures of PZT films grown on RuO2 electrodes with and without the 100Å Pt interlayer are compared. In addition, the voltage, temperature, and polarity dependence of the leakage current in these samples was measured. The data suggest that leakage current in these samples is most likely Schottky emission controlled. The barrier heights are determined to be about 0.80 and 0.73 eV for the top and bottom interfaces, respectively.
Effects of Annealings on Pt/TiN/Ti Interfacial Reactions
Authors: Varniere F. , Eakim B. , Agius B. , Bisaro R. , Olivier J. , Chevrier G. , Achard H. , Mace H. , Peccoud L. 
Published: April 2011

ABSTRACTThe selection of a suitable electrode and barrier layer is important in the integration of lead zirconate titanate (PZT) into memory circuits. Processing at elevated temperatures of up to 800°C can give rise to diffusion processes and therefore to formation of poor quality layers.In this paper we used Rutherford Backscattering Spectrometry (RBS), Auger Electron Spectrometry (AES), and X-ray Diffraction (XRD) to study the effects of annealings on the interdiffusion of Pt/TiN/Ti trilayers deposited on BPSG/Si substrates. The wafers were annealed in Ar, N2 or O2 ambients with temperatures ranging from 550 to 700°C for 60 min, 30 min or 30 sec. Drastic changes occur when the as deposited Pt/TiN/Ti layers on BPSG/Si structures are exposed to classical heat treatment: oxidation induces diffusion of Ti into Pt and oxidation of Ti is also observed. Regardeless of annealing proceedure used, significant improvement in the interdiffusion of Pt, Ti and O have been achieved when the TiN/Ti/BPSG/Si structure was heated up to 450°C in vacuum. Platinum films deposited on such a structure seem to be a promising barrier layer for PZT film elements as there was no indication of Pb diffusion into the underlying layers and furthermore the desired crystal structure was obtained.
Influence of Ti Sources on Properties of (Ba,Sr)TiO3 Films Prepared by Liquid Source CVD
Authors: Kawahara T. , Yamamuka M. , Makita T. , Yuuki A. , Mikami N. , Ono K. 
Published: April 2011

ABSTRACTWe have investigated influences of Ti sources on properties of (Ba,Sr)TiO3 [BST] films prepared on Pt/SiO2/Si substrates by liquid source chemical vapor deposition (liquid source CVD): TiO(DPM)2 [titanyl bis (dipivaloylmethanato), TiO(C11 H19O2)2], Ti(O-i-Pr)2 (DPM)2 [bis (isopropoxy) bis (dipivaloylmethanato) titanium, Ti(o-i-C3H7)2(C11H19O2)2], and TTIP [titanium tetraisopropoxide, Ti(O-i-C3H7)4]. Improved electrical properties and step coverage were obtained using TiO(DPM)2 at a substrate temperature TS=420'C and a reactor pressure P=1.5Torr as follows: a dielectric constant ε=210, equivalent SiO2 thickness teq=0.51nm, leakage current density JL=6.6×10∼−8A/cm2 at +1.1V, dielectric loss tan δ=0.007, and coverage of 0.8. However, hillocks appeared on the BST film surface under these conditions, while the film surfaces were relatively smooth using TTIP. The density of these hillocks appeared to be related to the BST(110) peak intensity of the X-ray diffraction pattern.
Autostoichiometric Vapor Deposition of Multicomponent Oxides
Authors: Chour K.W. , Xu R. 
Published: April 2011

ABSTRACTThe theoretical basis of an autostoichiometric vapor deposition method is discussed. We try to define and analyze through the stagnant film model for vapor deposition, the mechanism through which the stoichiometry of a multicomponent oxide film can be precisely controlled. It is found that the utilization of a thermally stable, heterometallic molecular precursor, and a chemical reaction scheme which partially protects the integrity of the precursor molecule during deposition are essential for autostoichiometric vapor deposition. An ideal deposition reaction is the vapor phase hydrolysis, substrate surface polycondensation of volatile double alkoxides. A simple low pressure apparatus can be used to realize autostoichiometric vapor deposition.
Preparation and Characterization of Metal Alkoxide Derived Epitaxial Lead Titanate Based Thin Films
Authors: Nashimoto Keiichi , Nakamura Shigetoshi 
Published: April 2011

ABSTRACTEpitaxial and highly oriented lead titanate based thin films were prepared by a sol-gel process using non-hydrolyzed methoxyethoxide precursors and RTA process. PbTiO3 crystallized with preferred (001) or (100) orientation on SrTiO3 (100) and MgO (100). Solid phase (001) oriented epitaxial growth of PZT on SrTio3 was observed at 425°C, directly from the amorphous phase. That of PZT on MgO was observed at temperatures above 550°C, after the formation of pyrochlore phase. The PZT on SrTiO3 had a single (001) orientation and rocking curve full width at half maximum less than 0.08°. PZT showed a weak preferred (111) orientation on sapphire (0001) substrates, while highly (111) oriented PLT thin films were obtained on them. The guided wave modes were excited by a prism coupling for PZT thin films crystallized on SrTiO3 and MgO. Electrical properties of epitaxial PZT and PLT thin films on Nb-SrTiO3 substrates were characterized.
Dielectric and Ferroelectric Properties of Sol-Gel Derived PLZT Films
Authors: Teowee G. , Quackenbush E.L. , Baertlein C.D. , Boulton J.M. , Kneer E.A. , Uhlmann D.R. 
Published: April 2011

ABSTRACTThere has not been much exploration of PLZT film properties as a function of compostion reported in the literature. A survey of numerous PLZT films covering a wide spectrum of the PLZT phase diagram was undertaken to explore the dependence of film properties on composition. A series of sol-gel derived PLZT films were prepared on platinized Si wafers and fired to 700C to obtain the perovskite phase. The film compositions include PLZT x/65/35, x/20/80, x/53/47 for x = 0, 2, 4, 6, 8, 10 and 12 and 7.5/x/y where x/y = 70/30, 53/47, 20/80 and 0/100. These films were characterized for their dielectric and ferroelectric properties. The films definitely showed a strong dependence of final film properties on composition, providing a valuable tool for the material engineering of ferroelectric film properties.
The Influence of the Crystalline Structure on the Electrical Properties of BaTiO3/SrRuO, Heterostructures
Authors: Wills L.A. , Amano Jun 
Published: April 2011

ABSTRACTEpitaxial BaTiO3/SrRuO3 heterostructures were deposited on MgO and SrTiO3 substrates by 90° off-axis, rf-magnetron sputtering. A template layer growth was required to obtain epitaxy on MgO. The crystalline structure of the films was analyzed with x-ray diffraction. The leakage current and remanent polarization depended on the crystalline structure and processing parameters. The BaTiO3 thin films displayed remanent polarizations of 13 μC/cm2 and leakage current densities of 107 Amps/cm2 at 2 volts. The BaTiO3 thin films grown under optimal conditions displayed very little fatigue up to 5×108 cycles.
Enhancement of the Electrical Properties of BaTiO3 Films on GaAs Using Double Layer Structures
Authors: Chang L.H. , Anderson W.A. 
Published: April 2011

ABSTRACTFerroelectric BaTiO3 thin films have been directly deposited on n-GaAs with carrier concentration of 5.3–8.2×1017/cm2. The BaTiO3 thin films with a thickness in the range of 80–120 nm were prepared by RF magnetron sputtering with a substrate temperature of 300°C. The as-deposited BaTiO3 films appeared to be amorphous with relative dielectric constants of around 15 and gave flat capacitance-voltage (C-V) curves, indicating poor interface properties and very high oxide charge density. After rapid thermal annealing (RTA) at 800°C for 60 sec, the relative dielectric constant of the BaTiO3 film increased to 82 and a sharp C-V curve was observed with oxide charge density of about 7×1012/cm2. However, the leakage current density increased from 4×10'11 A/cm2 for as-deposited BaTiO3 to 2×105 A/cm2 for RTA(800°C)-BaTiO3 at a field of 4×105 V/cm. By taking advantage of the best properties from both as-deposited amorphous BaTiO3 films (low leakage current density) and RTA(800°C)-BaTiO3 (high dielectric constant) the double layer structure was designed to enhance the electrical properties of the BaTiO3 films on GaAs. The most promising results in regards to the dielectric property and leakage current density are 76.5 and 9.7×109 A/cm2, respectively, for the double layer RTA(500°C)-BaTiO3 on RTA(800°C)-BaTiO3 structures.
Epitaxial Growth of Ba1−xSr,TiO3 Films on Si by Pulsed Laser Deposition and Their Dielectric Properties
Authors: Lee Myung-Bok , Kawasaki Masashi , Yoshimoto Mamoru , Moon Bum-Ki , Ishiwara Hiroshi , Koinuma Hideomi 
Published: April 2011

ABSTRACTDielectric Ba1−xSrxTiO3 films were heteroepitaxially grown on Si (100) substrates by employing an epitaxial TiN interlayer. The crystallinity and surface morphology were investigated for the films prepared at various substrate temperatures and oxygen pressures. BaTiO3 and SrTiO3 films grown at 650°C and 550°C, respectively, at oxygen pressure of ∼105Torr had good crystallinity and very smooth surface morphology as observed by scanning electron microscopy and atomic force microscopy. Sharp interfaces with little interdiffusion of atoms were observed for these films by secondary ion mass spectrometry. Dielectric properties were evaluated for metal-insulator-metal capacitor structures, and revealed to be closely related to the crystallinity and surface morphology of films.
Thin Film Formation of Perovskite Type Dielectric and Ferroelectric Materials(MTiO3,M=Ca,Sr,Ba and Pb) by Pulsed Laser Deposition
Authors: Tabata Hitoshi , Tanaka Hidekazu , Kawai Tomoji 
Published: April 2011

ABSTRACTWe have formed thin films of ferroelectric and dielectric materials (BaTiO3, SrTiO3 and CaTiO3) by pulsed laser deposition on various kinds of substrates such as SrTiO3, LaAlO3 and MgO(100) single crystals. All the films can be formed epitaxially on the SrTiO3 substrate with c-axis orientation by choosing suitable conditions. The electrical behavior of these films such as dielectric constant and spontaneous polarization is quite similar to that of single crystals in bulk samples. The remanent polarization of BaTiO3 and PbTiO3 films are about 15 μC/cm2 and 80 μC/cm2, respectively. The value of 80 μC/cm2 is almost the same as that theoretically predicted and have not been obtain in the bulk samples. The unique advantage of the pulsed laser deposition technique is its ability to produce highly oriented stoichiometric films that show good electrical properties.
Investigation of the Characteristics of Ferroelectric Thin Films Deposited by Pulsed Laser Ablation
Authors: Sengupta S. , Vijay D.P. , Desu S.B. 
Published: April 2011

ABSTRACTFerroelectric thin films of barium strontium titanate (BSTO) have been deposited on bare and metallized substrates by pulsed laser ablation method under different oxygen ambients (150 mT and 50 mT). Under an oxygen pressure of 150 mT, the film composition was similar to that of its ablation target composition, viz. Ba0.4TiO3. However, when the films were deposited under the lower oxygen pressure, x-ray diffraction studies showed the presence of a secondary phase. The electrical characteristics of the films were measured to examine the effect of the stoichiometry on the dielectric constant and tunability. The results of this study will be presented.
Characterization of Post - Annealed PZT Thin Films Deposited Using Pulsed Laser Ablation
Authors: Alainen Jyrki Lapp , Frantti Johannes , Leppävuori Seppo 
Published: April 2011

ABSTRACTPulsed laser ablation was used to deposit Nd-doped lead zirconate titanate (PZT) thin films with a thickness of from 100 to 800 nm from a Pb0.97 Nd0.02(Zr0.55Ti0.45)O3 target. The films were ablated onto sapphire and MgO substrates using a XeCl excimer laser (pulse energy 50 mJ, wavelength 308 nm, pulse duration 20 ns). The distance between the target and the substrates was 40 mm, and the angle between the target normal and the incident beam was 45 °. The films were post-annealed in air at various temperatures (600 – 900 °C) with PZT powder. It was found that the laser beam energy density on the surface of the target had a significant effect on the composition of the films, the number of particulates on the surface of the films and the growth rates of the films. Lead deficiency was found in the films in the case of high fluence (> 1.5 J/cm2) while low fluence values (< 1.0 J/cm2) gave an excess of lead and too low Zr/(Zr+Ti) ratios. The particulate number density was low for fluence values between 0.5 and 1.5 J/cm2. EDS and X-ray diffraction was used to determine the composition and the crystal structure of the annealed films. The films deposited using a low fluence showed increasing tetragonal c/a-ratio with increasing post-annealing temperatures. Raman spectra measured from annealed films were found to be typical of PZT.
Preparation of Textured Sn2P2S6 Films and Their Piezoelectric Properties.
Authors: Arnautova E. , Protsenko N. , Sandjiev D. , Zakharchenko I. , Zadorognaya L. 
Published: April 2011

ABSTRACTPolycrystalline Sn2P2S6 films were prepared by “hot wall” method and studied for possible electronic application. This paper deals with the determination of correlation between the preferred crystallite orientation of the film and its piezoelectric parameters. It is shown that is possible to optimize the piezoelectric properties of Sn2P2S6 films by prescribing the certainrelief of the substrate surface.
The effect of rapid solidification by spinning and laser melting On the structure of sendust-type alloys
Authors: Sheftel Elena N. , Kaputkin Dmitry E. , Stroug Raissa E. 
Published: April 2011

AbstractDispersion strengthening of the most wear-resistant soft magnetic alloy Sendust (Fe-9.5 wt.%Si -5.5 wt.% Al, HV=5000 MPa) by carbide and boride phases allowed to increase its wear-resistance by a factor of 2 to 3. Hardness of the dispersion strengthened alloys is HV=5500–6250 MPa. The changes in grain size, ordering and hardness of the Sendust and two dispersion strengthened alloys have been studied after spinning and various regimes of laser melting. Both types of rapid solidification caused a significant decrease of both the solid solution grain size and the size of carbide and boride phases. While spinning only significantly decreased the amount of ordered Fe3(Si,Al) phase in all the alloys, laser melting completely suppressed the ordering. The hardness of the boride strengthened alloy increased up to 7550 MPa after laser melting.
Impression Creep of a Sn-Pb Eutectic Alloy
Authors: Yang Fuqian , Li J. C. M. 
Published: April 2011

AbstractImpression creep tests on a Sn-Pb eutectic alloy showed a hyperbolic sine stress dependence of impressing velocity and an activation energy of 55 kJ/mole which is independent of the punching stress. A finite element simulation showed that this phenomena could be explained by a constitutive law in which the creep rate is also a hyperbolic sine function of stress. This simulation also gives an impressing velocity which is proportional to the punch size for the same punching stress. Then by using lubrication theory, it is possible to relate this constitutive law to an interphase shearing mechanism in which the rate of interphase shear is a hyperbolic sine function of the shear stress. This theory gives a creep rate which depends inversely on the third power of grain size at low stresses.
Characterization of Melt Spun Cu-Nb Ribbons
Authors: Henne Mei Ling , Ebrahimi Fereshteh 
Published: April 2011

AbstractMicrostructure of rapidly solidified Cu-5wt%Nb ribbons produced by melt spinning was investigated by SEM and TEM techniques. Two heat treatments were done: 960°C 1 hour and 900° 3 hours. The microstructures contained three different type particles: (a)large particles located at the grain boundary, (b)small spherical particles located within the grains and at the grain boundaries, and (c)fine precipitates formed upon heat treatment. The evolution of the microstructure is discussed with regard to the previously reported studies.
Room temperature recrystallization of nanocrystalline thin copper foils
Authors: Dille J. , Delplancke J.-L. , Charlier J. , Winand R. 
Published: April 2011

AbstractThin copper foils (100 micrometers thick) are produced by electrolysis on anodized titanium substrates. A sharp distribution of grain diameter is observed around 200 nanometers. The X-ray diffraction pattern shows a slight preferential orientation of the crystals with the (111) planes parallel to the substrate. This X-ray diffraction pattern evolves at room temperature. After 60 days, a preferential orientation of the (200) planes parallel to the substrate is observed. This effect is associated with the recrystallisation of the foil with growth of large copper grains (diameter higher than 5 micrometers) as observed by high resolution transmission electron microscopy.The structural evolution of the copper foils is studied by electron microscopy, X-ray and electron diffractions at different temperatures.The mechanical properties of the foils are also studied as a function of time after electrodeposition.
Norman J. Petch and his Contributions to Materials Science
Authors: Armstrong Ronald W. 
Published: April 2011

AbstractNorman Petch was trained in chemistry at Queen Mary College in London, in metallurgy at Sheffield, and in physics at the Cavendish Laboratory, University of Cambridge. The quantitative nature of his crystallographically-based earliest papers, dealing with the positions of iron and carbon atoms in steel, very probably contributed to the meticulous nature of his follow-on mechanical properties research, initially, into the influence of polycrystal grain size on the plastic yielding and fracturing behavior of iron and steel materials at low temperatures. This work, that was complementary to studies of the yield point behavior of steel by his Cambridge colleague, E.O. Hall, led to the well-established Hall-Petch equation for the stress dependence on reciprocal square root of average grain diameter; perhaps, the most widely quoted equation in materials science. Norman Petch's research, with students and colleagues, led on to predictive and/or interpretive Hall-Petch connected relations for the influence of carbon on the friction stress of steel, hydrogen embrittlement influences on the yield and fracture of steel, the ductile-brittle transition behavior of iron and steel and related materials, the plastic deformation properties of brass and aluminum materials, and the fracturing behavior of ceramic materials and laminated composites.
A Phenomenological Approach to the Ductility in Ultra-Fine Grain, Rapidly Solidified Materials
Authors: Otooni M. A. 
Published: April 2011

AbstractCrystallization in amorphous materials produces polycrystalline materials with fine grains which can be on the order of 1–2 microns, depending on the extent of annealing. Ductility in these materials with this range of grain sizes is generally low. This paper deals primarily with the lack of ductility in these classes of materials and will present a quasi-mathematical approach to this phenomenon. It will be shown that the influence of the plastic zone, the dislocation-free zone, and the grain size can be expressed by a unique formalism from which the propagation of cracks, and the lack of ductility, can be readily predicted. These deductions will become evident from the results of recent simulation experiments which will provide evidence to support the most essential elements of the approach presented in this paper.
Effect of Ion Bombardment on the Structure and Properties of PECVD SiO2
Authors: Lee Jung H. , Kim Dong S. , Lee Young H. 
Published: April 2011

AbstractSiO2 films were deposited on silicon wafers at 25°C by plasma enhanced decomposition of tetraethoxysilane (TEOS) in a mixture of argon and oxygen. The deposition was performed in a rf-powered (13.56 MIHz) asymmetric plasma reactor. The effect of ion bombardment was evaluated by varying the ion energy flux (IEF) at the substrate surface from 0.93 to 9.94 W/cm2. On-line optical emission spectra (OES) revealed CO, CH, and H peaks whose absorption intensities increased with increasing applied power. On-line mass spectrometer data showed that the peak intensities of OC2H5, SiOH (m/e=45), and HSiOH (m/e=46) fragments decreased with increasing applied power indicating the decomposition of these species. FTIR spectra of the deposited films showed that the concentrations of Si-OH and trapped CO gases in the film decreased with increasing IEF. Also, the FTIR results and the refractive index measurements indicated that the film density increased as a function of IEF. The stoichiometry of the film did not change when IEF was below 2, but for IEF greater than 4.91 W/cm2, the film became Si-rich.
Studies of Pecvd and Ozone CVD Deposition Rate, Uniformity and Step Coverage
Authors: Guo Xin , Zhao J. , Qiao J. , Tabata A. , Pang B. , Galiano M. , Sinha A. 
Published: April 2011

AbstractChemical vapor deposition (CVD) has been used to deposit films such as silicon, silicon oxide, silicon nitride, tungsten, silicide, copper and titanium nitride in the semiconductor industry. The reaction driving forces for CVD are typically temperature for thermal CVD, plasma ionization for plasma enhanced CVD, or atomic oxygen for ozone CVD. In the recent years, plasma enhanced CVD (PECVD) and ozone CVD have found extensive applications in the semiconductor industry, due to the higher deposition rate and lower deposition temperature. For example, PECVD and ozone CVD are used to deposit almost all dielectric films such as silicon oxide and silicon nitride on a wafer. The dielectric films on wafers serve as insulating layers between conducting metal layers and as passivation layer on top of semiconductor devices.
Fabrication of Diamond and Diamond-Like Carbon by Low Pressure Inductively Coupled Plasma CVD
Authors: Okada Katsuyuki , Komatsu Shojiro , Ishigaki Takamasa , Matsumoto Seiichiro 
Published: April 2011

AbstractA 13.56 MHz inductively coupled plasma(ICP) system has been applied to fabricate diamond and diamond-like carbon from a CH4/H2/Ar plasma. The characterizations of the obtained deposits by transmission electron diffraction, reflection high energy electron diffraction, and Raman scattering revealed that the deposits are diamond crystallites, with crystal sizes ∼1μm, and that they partially include disordered microcrystalline graphite. Although contamination due to etching of the quartz tube exists, this was drastically suppressed by the electrostatic shield(Faraday shield).
Achieving High Nucleation Density of Diamond Film Under Low Pressures in Hot-Filament Chemical Vapor Deposition
Authors: Chen Yan , Mei Jun , Chen Qijin , Lin Zhangda 
Published: April 2011

AbstractDiamond have been deposited rapidly under low pressures (<0.1 Torr) via hot filament chemical vapor deposition (HFCVD) on either scratched or mirror-smooth single crystalline silicon and titanium with nucleation densities of 109–1011/cm2. The nucleation density increases with the pressure decreases. Hydrogen and methane were used as the gaseous source. Raman spectroscopy and scanning electron microscopy(SEM) were used to analyze the obtained films. This result breaks through the limit that diamond film can only be synthesized above 10 Torr, showing a promising prospect that, as is essential for heteroepitaxial growth of monocrystalline diamond films, diamond film can be easily nucleated on unscratched substrate via Hot Filament CVD.