bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrical Study of Schottky Barriers on Cleaved InP and GaAs (110) Surfaces
Authors: Newman N. , van Schilfgaarde M. , Kendelewicz T. , Spicer W. E. 
Published: March 2011

We have performed a systematic study of the electrical properties of a large number of metal/n-GaAs and metal/n-InP diodes. Diodes were fabricated on clean cleaved InP and GaAs (110) surfaces in ultra-high vacuum with in-situ metal deposition of Cr, Mn, Sn, Ni, Al, Pd, Cu, Ag and Au. Using current-voltage (I-V) and capacitance-voltage (C-V) measuring techniques, we were able to obtain very reliable and consistent determinations of the barrier height, θ/b, and ideality factor, n. All of the metal-semiconductor systems formed on lightly doped (< 5×1016/cm3) substrates were characterized by near-unity (1.05) ideality factors.The effects of doping on the electrical characteristics of the n-GaAs diodes were investigated. A decrease in the effective I-V barrier height, an increase in the ideality factor in forward bias and a strong voltage dependence on the thermionic emission currents in reverse bias were found for diodes formed on the more heavily doped samples. These changes are essentially metal-independent, but depend strongly on the doping of the substrate. The characterization (and elimination in some cases) of peripheral leakage currents from the thermionic emission current for the n-GaAs systems was found to be essential in obtaining consistent results in our work and in reinterpreting some of the prior work in the literature. The dominant leakage current in the GaAs diodes flows through a small area, low barrier at the periphery of the device and can be eliminated by mesa etching.
Uv-Ozone Cleaning of GaAs (100) Surfaces for Device Applications
Authors: Solomon J. S. , Smith S. R. 
Published: March 2011

ABSTRACTGaAs (100) substrates were subjected to UV-ozone, wet chemical, and thermal treatments prior to deposition of Ni contact structures. The use of UV-ozone showed marked improvement in the electrical characteristics compared to the wet chemical and thermal treatments alone. The major effect of UV-ozone is the nondestructive removal of carbonous contaminants. Results of C-V and I-V barrier height measurements on Ni contact structures fabricated on the treated surfaces are presented.
Electrical Properties of Epitaxial Silicide-Silicon Interfaces
Authors: Tung R. T. , Levi A. F. J. , Gibson J. M. , Ng K. K. , Chantre A. 
Published: March 2011

ABSTRACTThe Schottky barrier heights of single crystal NiSi2 layers on Si(111) have been studied by current-voltage, capacitance-voltage and activation energy techniques. Near ideal behavior is found for Schottky barriers grown on substrates cleaned at ∼820°C in ultrahigh vacuum. The Fermi level positions at the interfaces of single crystal type A and type B NiSi2 are shown to differ by ∼0.14 eV. Transmission electron microscopy demonstrated the epitaxial perfection of these suicide layers. At a cleaning temperature of 1050° C, the near surface region of lightly doped n-type Si was converted to p-type. The presence of a p-n junction was directly revealed by spreading resistance measurements and resulted in a high apparent Schottky barrier height (≥0.75 eV) which no longer bears immediate relationship to the interface Fermi level position.
Silicide-Silicon Interface States
Authors: Yang E. S. , Wu X. , Evans H. L. , Ho P. S. 
Published: March 2011

ABSTRACTThe existence and nature of localized states at metal-semiconductor interfaces are long-standing scientific issues that have not been resolved. As device dimensions continue to shrink and packing density continues to increase, interfaces at silicide-silicon contacts will be increasingly influential in determining the circuit behavior. Characterization of these interfaces, whether as ohmic contacts or rectifying junctions, is a necessity for microelectronics. Therefore, the study of silicide-silicon interfaces are important both scientifically and technologically. In this talk, we shall review the theoretical models of the Schottky barrier and the importance of interface states. We shall then introduce available experimental tools for interface state studies. In particular, we shall discuss the measurement of silicide-silicon interface states by an accurate-phase capacitance spectroscopy (APCS). Some of the devices were fabricated with standard chemical cleaning before metal evaporation. Others were prepared in an UHV chamber with heat cleaning before metal deposition. For palladium suicide diodes, the behavior of both chemically-cleaned and UHV-prepared samples is similar. The peak position of the capacitance spectrum correlates with the barrier height, and the magnitude of the peak decreases by a factor of three after annealing. In the case of nickel suicide diodes, a comparison between epitaxial and non-epitaxial interfaces shows much lower interface state density for the former. Experimental data indicate that suicide formation and interfacial perfection are important in specifying the Fermi level.
Electrical Characterization of the Oxide-Silicon Carbide Interface by MOS Conductance Technique
Authors: Chaudhry M. I. , Berry W. B. 
Published: March 2011

ABSTRACTThe electrical properties of the SiO2/SiC interface were studied using the conductance vs voltage (G-V) data for the metal-oxide-SiC (MOS) structure. It was found that the dry oxide contained too mjch charge either at the oxide-SiC interface or within the oxide films to obtain useful data. On the other hand the wet oxide invariably resulted in better capacitance and conductance data. The capacitance-voltage data showed that the SiC surface exhibited accumulation, depletion or inversion when the appropriate gate bias was applied. The conductance-voltage data indicate electronic surface states at the oxide-SiC interface. From this conductance data the interface state density has been estimated.
Epitaxial Growth Of Platinum-Group Metal Silicides On (111) SI
Authors: Chang Y. S. , Chu J. J. , Chen L. J. 
Published: March 2011

ABSTRACTEpitaxial ruthenium, osmium, rhodium and iridium suicides have been successfully grown on silicon. Electroless chemical plating was used to deposit platinum-group metal thin films on silicon. Two step annealing was found to be effective in inducing the growth and improving the quality of the epitaxial suicide on silicon.Transmission electron microscopy was applied to characterize the microstructures and determine the orientation relationships between epitaxial suicides and substrate Si. The compositions of deposited films were determined by scanning Auger electron spec-troscopy combined with depth profiling technique. The percentages of phosphorus were found to be in the range of 2–3 at. %.
Dlts Study of Oxide Traps Near the Si-SiO2 Interface
Authors: Vuillaume D. , Bourgoin J. C. 
Published: March 2011

ABSTRACTWe have used the DLTS (Deep Level Transient Spectroscopy) technique to characterize the traps of the oxide layer near the Si-SiO2 interface. Using the so-called saturating pulse DLTS, no saturation is observed when all the fast interface states are filled. This unusual behavior is interpreted by taking into account tunneling emission from oxide traps situated near the Si-SiO2 interface. We show how the deconvolution between interface states and oxide traps is allowed by introducing a model of tunneling emission from oxide traps into Si substrate, for the derivation of the DLTS response. By this way a depth localisation of these oxide traps is obtained : about 10 to 30 Å from the interface. The experimental study of the filling kinetics allows the determination of the concentration of these oxide traps (≈ 107 to 108 cm-2) and their associated tunneling capture cross-section (≈ 10-22 to 10-21 cm2). The validity of the model and measurements is rapidly discussed.
Microstructure and Magnetic Properties of CoCrTa Thin Films
Authors: Robinson C. J. , Howard J. K. 
Published: March 2011

ABSTRACTThe addition of Ta into thin sputtered films of CoCr greatly affects the microstructure and magnetic properties. Grain size, crystallographic preferred orientation and hysteresis parameters have been studied using transmission electron microscopy, electron diffraction, X-ray diffraction, polar Kerr effect and vibrating sample magnetometry techniques. Crystallographic preferred orientation is enhanced and is accompanied by increased perpendicular magnetic anisotropy. An extremely fine-grained microstructure is produced giving rise to films which show no morphological growth features. Thus the observed magnetocrystalline anisotropy is not attributed to columnar growth. Orientation in these films can be further increased by using under-layers of non-ferromagnetic CoCrTa alloys. The mechanism by which this occurs is discussed.
The Effect of the Oxide Interface on the Material and Electrical Properties of Polysilicon Contacts
Authors: Burk Dorothea E. , Newkirk Joseph W. , Jo Myung-Suk 
Published: March 2011

ABSTRACTA strong correlation has been found between the electrical, compositional and structural properties of the polysilicon contact and its interface with the heavily doped pol isi 1-emitter of a transistor. The integrity and thickness of the oxide interface is a major factor for improving the observed performance. Transistors for which the polysilicon was also the diffusion source for the emitter were studied.
Amorphous Silicon Ultra Thin Base Bipolar Phototransistor with High Performance (β=12, τx ≤30μs)
Authors: Chang C. Y. , Wu B. S. , Fang Y. K. , Lee R. H. 
Published: March 2011

ABSTRACTAn n+ /i/p /i/n amorphous silicon bipolar transistor has been successfully fabricated with a current gain of 12 and a response speed of 30 yS This new structure of bipolar transistor has a very thin base (200Å), therefore, high gain and high speed is obtainable. This device has a very promising applications as a flat panel display transistor and a phototransistor in photosensing element/array and photo coupler. Electrical and optical characteristics have been extensively investigated. Theoretical model and experimental results are plausibly in good agreement.Variation from the fundamental structure is also been developed, such as the Schottky emitter Al/i/p /i/n bipolar transistor.
Influence of Al Thin Film Properties on Wire Bondability of Semiconductor
Authors: Kobayashi M. , Hirota J. , Watanabe N. , Machida K. 
Published: March 2011

ABSTRACTIt is required for the reliable semiconductor to control high junction quality in wire bonding.It is expected that the Al film properties may considerably affect the junction quality. Yamamoto et al. studied the effects of Al film properties on the bondability in wire bonding by thermocompression bonding system, and disclosed that the breakability of oxide film on the Al is a key factor. [1]In this report, effects of fabrication condition, properties and bond-ability of Al thin film were investigated in wire bonding by thermosonic bonding system. As a result, it has clarified that concentration of impurities in the Al film is an extremely influential factor for the stability of adhesion and the expansion of alloying region in the junction boundary, that is, for the improvement of junction quality.
Decohesion of Thin Films From Ceramic Substrates
Authors: Cannon R. M. , Fisher R. M. , Evans A. G. 
Published: March 2011

ABSTRACTDecohesion of thin films from ceramic or semiconductor substrates is strongly influenced by internal stresses in films and stress concentrations from edges or flaws as well as by interfacial fracture energy. Residual stresses can cause spontaneous delamination, splitting and curling of films under tension or delamination, buckling and spal ling of films under residual compression, even with good interfacial bonding. Delamination behavior is considered using simple fracture mechanics models, supplemented with preliminary measurements of interfacial fracture energies. Formation conditions largely control internal stresses in films; whereas fracture energies are dictated by interfacial chemistry and mechanical factors such as plasticity.
An Investigation of The Bond Between Layers of Consolidated Amorphous Ribbon (Powercore™ Strip)
Authors: Raybould D. , Diebold A. 
Published: March 2011

ABSTRACTThin amorphous metal ribbons can be bonded together to form a thick strip which remains amorphous. This, PowercoreTM strip, has similar magnetic properties to the annealed thin ribbon and so is a direct substitute for silicon steel in power transformers. Its good properties are partially a result of the nature of the bond between the layers of ribbon. This paper reports on a study of this bond by Auger microscopy and laser acoustic microscopy.
Correlation between Fracture Mechanical and Atom Probe Investigations on Metallic Glass Ribbon
Authors: Calvo M. , Menand A. , Osterstock F. , Chermant J.L. 
Published: March 2011

ABSTRACTMetallic glasses have good mechanical and magnetical properties. However they embrittle after annealing and/or low temperature testing. In this paper, we describe the rupture of atom probe tips using fracture mechanical measurements. We found boron rich areas which seem to be interconnected and more numerous after annealing and act as crack nuclei. The good correlation between the calculated and the measured size of the critical defect seem to confirm that the boron segregations are on the origin of embrittlement and gives good ground for further straightforward investigations.
Formation of Quasicrystals In Rapidly Solidified Al Alloys
Authors: Schaefer Robert J. , Bendersky Leonid A 
Published: March 2011

ABSTRACTElectron beam surface melting has been used to study Al-Mn and Al-Mn-Si alloys subjected to a wide range of solidification conditions. Several of the reported equilibrium intermetallic phases are not found even at moderate growth rates. Beyond a composition-dependent critical velocity the equilibrium phases are all replaced by the quasicrystalline icosahedral and decagonal (T) phases. The icosahedral phase is favored over the T phase by higher solidification velocities. The addition of Si to Al-Mn alloys eliminates the T phase, but does not significantly facilitate the formation of the icosahedral phase by electron beam melting because the ternary α and β phases of Al-Mn-Si are able to grow rapidly into the electron beam melts.
Formation and Thermal Stability of Quasi Crystalline and Other Metastable Al-RICH Al-Mn Phases
Authors: Quan M.X. , Giessen B.C. 
Published: March 2011

ABSTRACTRSP of Al-rich Al-Mn alloys is known to produce several metastable phases, including (with increasing Mn content) supersaturated Al solid solution and two non-crystallographic phases, identified in the literature as an icosahedral phase (I) and a (probably) decagonal phase (T) with translational symmetry in one direction. The formation of these phases in the composition range from 8 to 30 at. pct. Mn has been studied in melt-spun and arc-furnace quenched alloys. The thermal transformation characteristics of all metastable phases were measured by DSC; transformation temperatures, enthalpies and activation energies were determined. At compositions from 17 to 20 at. pct. Mn, two transformations were observed. Noteworthy results include: smeared out (slow-onset) reactions, transformation temperatures dropping sharply toward lower Mn contents, transformation enthalpies rising steeply in the same range, and activation energies ranging from ~40 kcal/gmol for the low-temperature process (at ~763 K) to ~80 kcal/gmol for the high temperature process (~883 K).
A Study of Amorphous Erbium-Based Alloys Formed by Near-Isothermal Cold-Rolling of Elemental Composites
Authors: Atzmon Michael , Unruh Karl M. , Politis Constantin , Johnson William L. , Keck W. M. 
Published: March 2011

ABSTRACTWe report the formation of single-phase amorphous Cu-Er and Ni-Er alloys in bulk form by cold-rolling of composites prepared from elemental foils. As for previously reported cases of metallic glass formation by solid-state reaction, the driving force for the reaction is the negative enthalpy of mixing of the constituent elements. It occurs during deformation close to room temperature. Amorphous Cu7 2 Er2 8 was also produced by high-energy ball-milling of the elemental powders as well as by sputtering and liquid quenching. The alloys obtained were characterized by means of differential scanning calorimetry and x-ray diffraction. The crystallization behavior observed and the radial distribution functions obtained showed good agreement between the alloys prepared by different methods.
Deposition of TiN Films by Reactive Sputtering with Targets Facing Type of High Rate Sputtering
Authors: Naoe M. , Hoshi Y. 
Published: March 2011

ABSTRACTTiN films lμm thick were deposited on SKH55 alloy substrate at various substrate bias voltage by a reactive sputtering of Ti target in a mixture of Ar (1 mTorr) and N2 (1 mTorr) with a Target Facing type of high rate sputtering apparatus. The color of the film changes in the order of yellow, golden, silver and golden as the substrate bias voltage increases from 0 to 200 V. The reflection ratio and Vicker's hardness of the film also changes with the bias voltage. Besides, the change of the reflection factor corresponds well to the change of theVicker's hardness of the film. The films with silver color and maximum reflection ratio which are obtained at a rf bias voltage around 100 V, have the largest value of the Vicker's hardness about 3500. While, the films with golden color and small reflection factor, which are obtained at both rf bias voltage around 80 V and 150 V, have the lowest Vicker's hardness of about 1500.
Particle Coarsening of Dispersoids In Rapidly Solidified Ti-5Sn-3Y
Authors: Lu Y.Z. , Giessen B.C. , Whang S.H. 
Published: March 2011

ABSTRACTRapidly solidified Ti alloys containing rare earth metal dispersoids, such as La or Er, have excellent resistance to coarsening at elevated temperature (700–900°C). In particular, the coarsening of the dispersoid particles in RSP Ti-5Sn-3Y was studied; these particles were found to be Y5Sn3. The measured growth kinetics were found to be compatible with the modified LSW model; it was concluded from the observed parameters that in this alloy the diffusion rate of Y is the rate determining factor, providing a measurement of the diffusion coefficient of Y in a Ti matrix and yielding its activation energy Q = 272 kJ/mole.
Transition from A Planar Interface to Cellular and Dendritic Structures During Rapid Solidification Processing
Authors: Laxmanan V. 
Published: March 2011

ABSTRACTMicrostructural transitions occurring during solidification processes may be described in terms of three dimensionless parameters, s, p and σC, which include among them various processing variables and relevant material constants. The dimensionless parameter, s, in particular offers a convenient description of both planar-cellular and cell-dendrite transitions. The relationships between σC, s and p predicted by various dendrite growth models have been summarized.
Creep Deformation of Ultrafine Grained Ni7 5B1 7Si8
Authors: Nussbaum Gilles , Ast Dieter G. 
Published: March 2011

ABSTRACTThe creep behavior of the fine grained, intermetallic superplastic alloy of overall composition Ni7 5 B1 7Si8 prepared by crystallizing an amorphous precursor was studied in the temperature range between 500 and 615°C, the stress range between 36 and 800 MPa, and for grain sizes between 6.8 and 1.12*10−5 mm. The strain rates measured varied between 10−7 and 6*10−5 sec−1.Two different creep deformation mechanisms were observed. At low applied stresses, the material deformed in a diffusion controlled mode, with proportional to σ1. No dislocations developed in the grains, and the activation energy for creep was 4 eV. This value is higher than the self-diffusion of Ni in Ni (the principal constituent in the alloy) in agreement with observation in other Ni based alloy systems. At high applied stresses, a second mechanism became rate limiting. The activation energy of this process is about 0.6 eV and dislocations develop in the interior of grains when this mechanism operates.The transition between the two regimes is grain size and temperature dependent and occurs at about 400 MPa at a deformation temperature of 550°C and a grain size of 6.8 10−5 mm. An analysis of the grain size dependence of creep strain rate as well as its absolute value indicates that the low stress regime is Coble type creep.
Fracture Processes in Fully Crystallized Co84Nb10B6 Metallic Glass
Authors: Megusar Janez , Vargas Tina , Grant Nicholas J. 
Published: March 2011

ABSTRACTFracture processes have been studied in a fully crystallized Co84Nb10B6 glass, with the mean grain size ranging from 43 nm to 0.65 μm. Tensile tested specimens with a mean grain size≥ 0.3 μm showed a ductile (dimple) fracture with microvoids initiated at the boride-cobalt matrix interfaces. As the mean grain size (more correctly, the corresponding mean free path of the deforming cobalt phase) was ≤ 0.1 μm, the fracture process may be similarly initiated by the microvoid formation at the boride-cobalt interface. However, one-to-one correspondence between dimples and boride particles may not be preserved. As a result, dimples become more shallow and may include several boride particles instead. Although the fracture surface of the brittle fine grained Co84Nb10B6 alloy gives an appearance of a cleavage fracture on a macroscale, it is distinctly different, by allowing for the microvoid formation on a microscale.
Copper-Base Alloys Processed by Rapid Solidification and Ion Implantation
Authors: Wood J.V. , Elvidge C.J. , Johnson E. , Johansen A. , Sarholt-Kristensen L. , Henriksen O. 
Published: March 2011

ABSTRACTAlloys of Cu-Sn and Cu-B have been processed by both melt spinning and ion implantation. In some instances (eg Cu-Sn alloys) rapidly solidified ribbons have been subjected to further implantation. This paper describes the similarities and differences in structure of materials subjected to a dynamic and contained process. For example in Cu-B alloys (up to 2wt% Boron) extended solubility is found in implanted alloys which is not present to the same degree in rapidly solidified alloys of the same composition. Likewise the range and nature of the reversible martensitic transformation is different in both cases as examined by electron microscopy and differential scanning calorimetry.
Differences between Sputtering Methods in The Formation of Amorphous Magnetic Alloy Films
Authors: Hoshi Y. , Naoe M. 
Published: March 2011

ABSTRACTFe-Si, Co-Ta and Co-Zr amorphous films have been deposited by using various sputtering methods (conventional rf diode sputtering, rf triode sputtering, dc Targets Facing type sputtering (dc TF sputtering) and dual ion beam sputtering (DIB sputtering)). The lower limit of the Si and Ta content to form amorphous Fe-Si and Co-Ta films changes significantly with the sputtering method. These differences between the sputtering methods are mainly caused by the differences in the plasma potential which affects the amount of ion bombardment to the film surface during sputtering,and the minimum content of Si or Ta to obtain amorphous films decreases as the plasma potential increases. These results indicate that the ion bombardment suppresses the growth of crystallites and promotes the formation of the films with amorphous structures. This is confirmed by the deposition of Co-Ta and Co-Zr amorphous films under the condition of various amount of ion bombardment by using a DIB sputtering system.