bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measuring Thin Film Fracture Toughness Using the Indentation Sinking-in Effect and Focused Ion Beam
Authors: Tsui Ting Y. , Joo Young-Chang 
Published: April 2011

AbstractA new experimental technique is developed to measure the fracture toughness of a hard metal thin film deposited on a soft substrate. A pre-crack was fabricated in the thin film by using the advanced focused ion beam (FIB) milling techniques. The crack extension force was generated by means of the indentation sinking-in effect. The effect creates a bending moment and tensile stress on the hard thin film near the indentation, which promotes crack growth. The amount of crack tip blunting prior to the critical failure was measured from the FIB cross-sectioned micrographs. By using the crack tip opening displacement model (CTOD), the fracture toughness of the thin film was calculated. The results show the nickel phosphorus (NiP) thin film fracture toughness is at least 15.0MPa√m. The finite element method (FEM) was used to understand the modes of mixity near the crack tip. The results indicate the crack tip modes of mixity are dominated by the Mode I opening, provided the indentation is sufficiently far from the pre-crack or the indentation depths is small when compared with the film thickness.
Anisotropic Plasma Etching of Barium-Strontium-Titanate Thin Films for 4 Gbit DRAM Devices
Authors: Schneider Stefan , Kennard Mark A. , Waser Raine 
Published: April 2011

AbstractReactive Ion Etching of Ba0.7Sr0.3TiO3 (BST) thin films was studied using a Lam Research Corporation TCP™ 9400SE high density, low pressure plasma reactor. The BST thin films were etched with a variety of reactive gas combinations in a transformer coupled plasma (TCP) by varying etching parameters such as plasma density, DC bias to wafer susceptor, gas pressure, and -flow. The etch process was characterized by measuring the etch rate, etch selectivity to photo resist and SiO2 etch profiles, side wall deposition (fence), and etch product residues. Plasma etching of BST was found to be dominated by physical sputtering. With the chemistries used, the etch products have little or no volatility. Such a process regime is expected to contaminate the wafer with sidewall deposition (fences) and residues, which are both detrimental for further processing and may cause a possible particle problem and a low mean time between cleaning the process tool. The photoresist mask thickness and slope were varied to characterize the relationship between profile and residue. The photoresist mask was sloped using in situ plasma processing. Through optimization of mask and etch parameters, an etch process suitable for integration of BST capacitors into ULSI structures was achieved.
Low Temperature Preparation of Sr2(Ta1-x, Nbx)2O7 Ferroelectric Thin Film by Pulsed Laser Deposition
Authors: Noda Minoru , Nakaiso Toshiyuki , Sugiyama Hideki , Okuyama Masanori 
Published: April 2011

AbstractPreferentially (151)-oriented Sr2(Ta1-x, Nbx)2O7 (STN) thin films on Pt have been prepared at temperatures as low as 550 and 600°C, in O2 and N2O atmospheres, respectively, by pulsed laser deposition (PLD). The temperatures are significantly lower than those prepared by sol-gel methods, where 950°C was reported. These are the lowest growth temperatures of crystalline STN thin films. Composition ratio (x) in the target material was determined to be around 0.3 from measurement of the Curie temperature and ferroelectric properties. Active oxygen generated by laser irradiation in ambient O2 or N2O atmosphere is found to be very effective for chemical reaction, and decreases the growth temperature of crystalline STN films. It is also confirmed by surface AFM and cross-sectional SEM observations that the film has a columnar-shaped structure with grain size ranging from 50 to 100 nm. Remanent polarization (Pr) and coercive field (Ec) are 0.4μ C/cm2 and 30 kV/cm, respectively. Finally, we expect the low temperature STN film prepared by PLD to be a promising ferroelectric for the application in ferroelectric memory FETs.
Frequency Dependence of the Coercive Voltage of Ferroelectric Thin Films
Authors: Waser R. , Lohse O. , Grossmann M. , Boettger U. , Bolten D. , Tiedke S. 
Published: April 2011

AbstractRecent progress in the measuring techniques based on a combination of a quasistatic P-V analysis, conventional dynamic hysteresis measurements, and fast pulse characterization allows to determine the coercive voltage as a function of the frequency over a range of more than seven orders of magnitude. In this review, we explain the experimental techniques and present the results for the thin film systems of SrBi2Ta2O9 (SBT) and Pb(ZrTi)O3 (PZT). Theoretical models of the correlation between the ferroelectric relaxation and the coercive voltage are discussed in the light of the new data.
Magnetooptic Waveguide Material Structures and Devices
Authors: Tsai Chen S. , Su Jun 
Published: April 2011

AbstractRecent advances in the techniques for preparation of Ce-doped yttrium iron garnet (YIG) films on gadolinium gallium garnet (GGG) and semiconductor substrates, hybrid material structures of YIG/GGG- gallium arsenide (GaAs) combination, and the resulting microwave and guided-wave magnetooptic (MO) devices are presented. For example, high-efficiency MO Bragg cell modulators using the YIG/GGG-alumina material structure have been realized using a non-uniform bias magnetic field as well as an electronic feedback. Such MO modulators are being used to construct integrated optic devices such as optical scanners, switches, and frequency shifters. Also, a wideband microwave bandstop filter with a carrier frequency tuning range as high as 2.5 to 23.0 GHz using the YIG/GGG-GaAs material structure has been realized. The same material structure can be employed to perform MO Bragg diffraction experiment at ultrahigh carrier frequencies.
BaTiO3 Waveguides on MgO Buffered-Sapphire Single Crystals
Authors: Lisoni Judit G. , Siegert M. , Lei C. H. , Jia C. L. , Schubert J. , Zander W. , Buchal Ch. 
Published: April 2011

AbstractWithin our program to develop ferroelectric thin film optical waveguides, we have studied the growth of epitaxial waveguides BaTiO3 on r-plane sapphire substrates with a MgO buffer layer. The films were prepared by pulsed laser deposition (PLD). Their structural properties were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), Rutherford backscattering (RBS) in random and channeling (RBS-c) configuration and atomic force microscopy (AFM). They displayed good crystalline quality, characterized by an RBS-c minimum yield of about 4–6%, a full width at half maximum (FWHM) of the XRD rocking curve measurement of the BaTiO3(200) reflection of 0.32° and a rms roughness of 1.2 nm in a film of ∼ 1.0 μm thickness. The epitaxial relationship was found to be BaTiO3(100) // MgO(100) // A12O3(1102). The refractive index, the birefringence and the optical losses have been measured.
Excited State Absorption in Dendrimers Incorporating Diphenylaminodiphenylpolyene Moieties Via Photo-Induced Electron Transfer
Authors: Sonnenberg W. , Hyfield A , Short K , Spangler L. , Spangler C. 
Published: April 2011

AbstractDuring the past decade there has been considerable progress in the design of new organic materials for optical power limiting (OPL) applications. Among the more promising of the new material approaches are reverse saturable absorbers (RSAs) which derive their optical limiting capability from the photogeneration of highly absorbing transient excited states. Most of the previous research in this field has focused on excited state absorption from singlet or triplet states whose cross-sections are greater than the original S0 – S1 transition- However, other transient states, such as polaronic radical ions or bipolaronic diions, formed by photo-induced electron transfer, are attractive alternatives. We have initiated studies to determine if these transient charge states can be photo-generated efficiently, and if their excited states absorption and lifetimes are acceptable for current optical power limiting requirements.
Phosphorescence Studies of Reverse Saturable Absorption Materials
Authors: Pooler E. S. , Clark C. M. , Kirkpatrick S. M. 
Published: April 2011

AbstractPhosphorescence studies of reverse saturable absorption materials (RSA) are discussed. Absorption and emission measurements of an RSA material, specifically Zinc 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrin (ZnOBP), are performed in a proprietary host polymer. Spectra are analyzed to estimate the relative energy level of the first triplet state of ZnOBP with respect to the ground state.
Strain Analysis in Thin La1−xCaxMnO3 Films by Grazing Incidence X-ray Scattering
Authors: Petit M. , Martinez-Miranda L. J. , Rajeswari M. , Biswas A. , Kang D. J. , Venkatesan T. 
Published: April 2011

AbstractWe have performed depth profile analyses of the lattice parameters in epitaxial thin films of La1−xCaxMno3 (LCMO), where x = 0.33 or 0.3, to understand the evolution of strain relaxation processes in these materials. The analyses were done using Grazing Incidence X-ray Scattering (GIXS) on films of different thicnesses on two different substrates, (100) oriented LaAlO3 (LAO), with a lattice mismatch of ∼2% and (110) oriented NGO, with a lattice mismatch of less than 0.1%. Films grown on LAO can exhibit up to three in-plane strained lattice constants, corresponding to a slight orthorhombic distortion of the crystal, as well as near-surface and columnar lattice relaxation. As a function of film thickness, a crossover from a strained film to a mixture of strained and relaxed regions in the film occurs in the range of 700 Å. The structural evolution at this thickness coincides with a change in the resistivity curve near the metalinsulator transition. The in-plane compressive strain has a range of 0.2 – 1.5%, depending on the film thickness for filsm in the range of 400 - 1500 A.
Colossal Magnetoresistance in New Manganites
Authors: Shen C. H. , Liu R. S. , Hu S. F. , Lin J. G. , Huang C. Y. 
Published: April 2011

AbstractThe evolution of structural, electrical and magnetic properties with the isovalent chemical substitution of Ca2+ into the Sr2+ sites in new series of two-dimensional La1.2(Srl.8−XCax)Mn2O7 compounds (x = 0 ∼ 1.8) and three-dimensional La0.6(Sr0.4−xCax)MnO3 compounds (x = 0 ∼ 0.4) are investigated. The highest magnetoresistance (MR) ratios [ρ(0) - ρ(H) / ρ(0)] of 52 % (H = 1.5 T) at 102 K and 13 % (H = 1.5 T) at 210 K were observed for the x = 0.4 samples in La1.2(Sr1.8−xCax Mn2O7 and La0.6(Sr0.4−xCax)MnO3, respectively. The Curie temperatures (Tc) decreased from 135 K to 102 K and 370 K to 270 K for x = 0 to 0.4 in La1.2(Sr1.8−xCax)Mn2O7 and La0.6(Sr0.4−xCax)MnO3, respectively. The compositional dependence of the structural variation has been found in La0.6(Sr0.4−xCax)MnO3. Our results confirm that the dimensionality as well as ionic size plays an important role in controlling the colossal magnetoresistance in manganites.
B-Site Doped Lanthanum Strontium Manganites by the DAAS Technique
Authors: Yang S. , Kolody M.R. , Lin C.-T. , Adams P.M. , Speckman D.M. 
Published: April 2011

AbstractMagnetic perovskites of the general form La0.7Sr0.3Mn1−yFeyO3 (y = 0, 0.05, 0.10, and 0.15) have successfully been synthesized using deposition by aqueous acetate solution (DAAS). Crystalline, iron-doped, lanthanum strontium manganite (Fe-doped LSMO) powders are obtained by preparing an aqueous solution of metal acetate precursors in the proper stoichiometry, drying the solution to generate a glassy gel, consolidating the gel, and then firing the gel for short periods of time (<2hrs). This novel technique has the potential for depositing large area thin films with high throughput and low cost. Powder samples of La0.7Sr0.3Mn1−yFeyO3 prepared by DAAS and annealed for 100 minutes at 1200°C are of high purity, are single phase, and exhibit excellent electrical and magnetic characteristics. Powders annealed at 1200°C or greater exhibit sharp metalinsulator transitions. Increasing the iron dopant concentration in these powders from 0% to 15% decreases the metal-insulator transition temperature of these samples from ∼360K to about 140K. The resistivity of these powders also increases with increasing substitution of the lattice B-site with iron, as does the unit cell volume of the lattice. Preparation of an iron doped LSMO powder that exhibits a maximum magnetoresistance at 305K was successfully carried out via a careful selection of iron content and anneal temperature. This compound, La0.7Sr0.3Mn0.93Fe0.07O3, exhibits a magnetoresistance of 40% at 305K and an applied field of 5 Tesla.
Two Peak Effect in GMR: A Chemical Effect?
Authors: Vertruyen B. , Rulmont A. , Dorbolo S. , Bougrine H. , Vanderbemden Ph. , Ausloos M. , Cloots R. 
Published: April 2011

AbstractWe show that the synthesis conditions have a dramatic influence on the resistivity behavior of calcium and sodium doped LaMnO3. Several samples prepared by lowtemperature techniques exhibit a double-peaked curve of resistance versus temperature. The model of spin-polarized intergranular tunneling provides a good approach to discuss our experimental results. Grain size and crystallinity are proved to be essential parameters, which are strongly influenced by the preparation process (e.g. the precursors nature and the thermal treatment).
Electrodynamic Properties of Single-Crystal and Thin-Film Strontium Titanate, and Thin-Film Barium Strontium Titanate
Authors: Findikoglu A.T. , Jia Q.X. , Kwon C. , Gibbons B.J. , Rasmussen K.Ø. , Fan Y. , Reagor D.W. , Bishop A.R. 
Published: April 2011

AbstractWe have used a coplanar waveguide structure to study broadband electrodynamic properties of single-crystal and thin-film strontium titanate (STO), and thin-film barium strontium titanate (BSTO). We have implemented low-frequency capacitance (100 Hz - 1 MHz), swept-frequency transmittance (45 MHz - 4 GHz), and time-domain transmittance (dc - several GHz) measurements to determine effective refractive index (or, dielectric constant), and dissipation factor (or, loss tangent) as a function of dc bias (up to 4×106 V/m) and temperature (20 - 300 K). The STO samples used superconducting electrodes and were designed to operate at cryogenic temperatures, whereas BSTO samples used normal conducting electrodes and exhibited optimal performance around room temperature. By using nearly identical electrode geometries for all devices, we were able to conduct a direct comparative study among them, and investigate not only single-crystal vs thin-film, but also cryogenic vs room-temperature applications.
Relative Stability of Silicon Self-Interstitial Defects
Authors: Subramanian G. , Jones K.S. , Law M.E. , Caturla M.J. , Theiss S. , Rubia T. Diaz de la 
Published: April 2011

Abstract{311) defects and dislocation loops are formed after ion-implantation and annealing of a silicon wafer. Recent Transmission Electron Microscopy studies by Li and Jones have shown that sub-threshold dislocation loops nucleate from {311} defects. In our study, the conjugate gradient method with the Stillinger Weber potential is used to relax different configurations such as {311} defects with a maximum of five chains and perfect dislocation loops. From the formation energies thus obtained we find that there is an optimal width for each length of the {311} defects. Moreover the relative stability of {311}s and loops is studied as a function of defect size. We observe that at very small sizes the perfect loops are more stable than the {311}s. This may provide an explanation for the experimental observation by Robertson et al that, in an annealing study of end of range damage of amorphized samples, 45% of the loops had nucleated in the first 10 minutes of anneal. Out of these 25% of the loops could not have nucleated by unfaulting of {311}s. We propose that homogeneous nucleation, as against unfaulting of the {311}s, could be the source of these sub-microscopic loops.
Activation of Implanted Poly Gates by Short Cycle Time Annealing
Authors: Fiory A. T. , Bourdelle K. K. 
Published: April 2011

AbstractAmorphous silicon films with B, P, and As implants were activated with thermal anneals that include spiking to the maximum temperature. Films were grown over thermal oxide by chemical vapor deposition as two separately implanted 50-nm layers for manipulating dopant placement and diffusion. Electrical activation was determined by Hall van der Pauw and MOS C-V, and dopant diffusion was profiled by secondary ion mass spectroscopy (SIMS). Flat-band voltage was used to benchmark relative thermal budgets for p-type poly. Temperature-time relationships are used to deduce effective activation energies.
Remote Plasma Nitridation of In-Situ Steam Generated (ISSG) Oxide
Authors: Al-Shareef H.N. , Karamcheti A. , Luo T.Y. , Brown G.A. , Watt V.H.C. , Jackson M.D. , Huff H.R. , Jallepally R. , Noble D. , Tam N. , Miner G. 
Published: April 2011

ABSTRACTElectrical performance of in-situ steam generated (ISSG) oxide nitrided using remote plasma nitridation (RPN) has been evaluated. An equivalent oxide thickness (EOT) of 1.6 nm with gate leakage current around 5×10−3 A/cm2 (at −1.5V) has been achieved. The leakage current of remote plasma nitrided ISSG oxide is lower than that of ISSG only, where more than one order of magnitude leakage current reduction (at the same EOT) has been achieved for some RPN conditions. Moreover, it is observed that the extent to which the RPN process conditions modify device parameters such as EOT, flatband voltage (VFB), and time-to-breakdown (tbd) increases with decreasing ISSG thickness. The thinner ISSG oxides appear to be more susceptible to plasma damage and accumulation of positively charged nitrogen atoms at the oxide/Si interface. Therefore, RPN processes that use lower temperature and shorter time are preferred for very thin oxides. The nitrogen content and profile in the samples evaluated using SIMS analysis, indicate that RPN offers higher nitrogen content and better nitrogen profile compared to conventional nitrogen incorporation methods such as NO annealing [1].
The characteristics of the Electrolyzed D.I.water with chemicals and the outline of the supply system
Authors: Shirakashi Mitsuhiko , Itoh Kenya , Katakabe Ichiro , Tsujimura Mamabu , Saitoh Takayuki , Yamada Kaoru , Miyashita Naoto , Kodera Masako , Matsui Yoshitaka 
Published: April 2011

ABSTRACTIn semiconductor device production, wafers are treated through many cleaning processes. Usually, several chemicals are used so as to match for several purposes like RCA cleaning method. As wafer size becomes larger, large amount of cleaning chemicals usage and waste are necessary, which becomes now a big problem. Considering the above, we developed the Electrolyzed D.I.water with chemicals supply system in order to minimize running cost of chemicals and waste treatment. It is feature that; 1) this system can generate the anode water of the acidity/high ORP (Oxidation-Reduction Potential) and the cathode water of the alkalinity/low ORP by electrolyzing D.I.water adding with a small quantity of chemicals; 2) this system can generate anode water and cathode water at the same time; 3) if necessary, the anode water can be diluted with D.I.water at the optional density, and it is possible with the cathode water that hydrogen peroxide is added. The anode water which shows acidity/high ORP has the effect of removing metal and organic contamination, and the cathode water which shows alkalinity/low ORP has the effect of particle removal. In this report, we explain the outline of this system and the basic characteristic of the Acid and Alkaline water made with this system and its performances.
Spin-dependent electron transport in ferromagnet/semiconductor Schottky barrier structures
Authors: Hirohata Atsufumi , Xu Yong-Bing , Guertler Christian M. , Anthony J. , Bland C. , Holmes Stuart N. 
Published: April 2011

ABSTRACTClear evidence for high efficiency spin-polarized electron transport across ferromagnet/semiconductor Schottky barrier interfaces was observed in Ni80Fe20/GaAs structures. Circularly polarized light was used to excite electrons with a spin polarization perpendicular to the film plane. At negative bias, an almost constant difference between the helicity-dependent photocurrent obtained for the magnetization parallel and perpendicular to the photon helicity was detected. An effective asymmetry, A, was also estimated from the helicity-dependent photocurrent difference, attributed to spin-polarized electron tunneling from GaAs to NiFe (spin filtering). A decreases with increasing photon energy, which is consistent with the energy-dependence of the asymmetry of photoexcited electrons in GaAs. Weak spin injection from NiFe to GaAs was seen at a bias corresponding to the Schottky barrier height, which is likely to occur via a ballistic process.
Influence of Growth Temperature and Phosphine Flow on CuPt Type Ordering in InGaP Grown by Chemical Beam Epitaxy
Authors: Bettini J. , de Carvalho M.M.G. , Hayashi M. A. , Cardoso L. P. , Ugarte D. 
Published: April 2011

ABSTRACTIn this work, In0.5Ga0.5P layers were grown by Chemical Beam Epitaxy on GaAs (001) substrates. A set of samples was grown with temperatures kept in the range of 500°C to 560°C with V/III ratio 15. Another set was grown at 560°C with V/II ratio varied in the range 15 to 35. The evolution of ordering as function of growth temperature and V/III ratio was evaluated by photoluminescence measurements at 77K, Transmission Electron Diffraction (TED) and images using Transmission Electron Microscopy (TEM)-Dark Field. A 48meV reduction in the band gap energy was measured by photoluminescence measurements at 77 K when growth temperature was increased. This result is associated to the occurrence of CuPtB ordering in the InGaP layers observed by TED. The TEM-Dark field examination shows that the ordered domains are larger for samples grown at higher temperaturesA small reduction in band gap, from 1.915eV to 1.902eV, occurs when the V/III ratio is increased from 15 to 35. The TED patterns present diffuse scattering for all samples. For those grown with higher V/III ratio, spots are also observed. TEM-dark field images show that the ordered regions become larger, elongated and inclined; some of them exhibit long range ordering
In Situ Study of Barrier Layers Using Spectroscopic Ellipsometry and Mass Spectroscopy of Recoiled Ions
Authors: Gao Y. , Mueller A.H. , Irene E.A. , Auciello O. , Krauss A.R. , Schultz J.A. 
Published: April 2011

ABSTRACTAn in situ study of barrier layers using spectroscopic ellipsometry (SE) and Time-of-Flight (ToF) mass spectroscopy of recoiled ions (MSRI) is presented. First the formation of copper silicides has been observed by real-time SE and in situ MSRI in annealed Cu/Si samples. Second TaSiN films as barrier layers for copper interconnects were investigated. Failure of the TaSiN layers in Cu/TaSiN/Si samples was detected by real-time SE during annealing and confirmed by in situ MSRI. The effect of nitrogen concentration on TaSiN film performance as a barrier was also examined. The stability of both TiN and TaSiN films as barriers for electrodes for dynamic random access memory (DRAM) devices has been studied. It is shown that a combination of in situ SE and MSRI can be used to monitor the evolution of barrier layers and detect the failure of barriers in real-time.