bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strain Relaxation in Epitaxial Heterostructures: Sensitivity of High Resolution X-Ray Diffraction
Authors: Goorsky M. S. , Horng S. T. , Sriffler S. R. , Stanis C. S. 
Published: March 2011

ABSTRACTComparison of high resolution x-ray diffraction and transmission electron microscopy measurements of Si-based heterostructures demonstrates that diffraction is much more sensitive to strain relaxation than previously reported. This study used as-grown and annealed Si1-x Gex structures grown on (001) Si by UHV/CVD. (004), (113), and (115) rocking curves were employed. Using the TEM measurements as a quantitative guide, relaxation was observed in rocking curves when the misfit dislocation line density was as low as 1 μ-1. Also, interference fringes strongly depend on the presence of interfacial defects. At higher dislocation densities, the diffraction peak from the epitaxial layer broadens considerably but does not shift to a position that represents complete relaxation. Broadening of the substrate diffraction peak also occurs, which is due to dislocations that loop into the substrate.
Single-Crystal AU-NI Solid Solutions Grown by MBE
Authors: Marty A. , Gilles B. , Patrat G. , Joud J. C. , Chamberod A. 
Published: March 2011

ABSTRACTEpitaxial solid solutions Au1-x Nix (100) have been obtained at room temperature on Au(100) substrates by the MBE technique. The layers are 10 nm-thick and the composition x has been varied up to 0.37. A large strain (2–3%) has been measured by X-ray diffraction. The lattice parameters have been measured in two perpendicular directions, perpendicular and parallel to the surface. In the latest case, the grazing-incidence technique has been used. Because this technique is very sensitive to the surface, the strain results may be re-interpreted if, the upperlOO nm are enriched in Au.
Molecular Dynamics Modeling of Growth, Micro-Structure and Stresses in Sputter-Deposited Films with Impurity Atom Incorporation
Authors: Fang C. C. , Jones F. , Prasad V. 
Published: March 2011

ABSTRACTThe structure and intrinsic stresses of sputter-deposited thin films are studied via a two-dimensional molecular dynamics (MD) model. Two body potentials are used to represent the interaction between film atoms, substrate atoms, ions and argon molecules. First, a nearly perfect substrate having zero stress is constructed using constant temperature and constant pressure algorithms. Then the film is deposited with and without in-situ argon ion bombardment and with and without an argon background gas; a source of impurities. The adatom energy is varied in order to investigate its influence on the film structure. During the simulation the film is allowed to expand and contract depending on the intrinsic stresses. The models demonstrate, for the first time, that the transition from large tensile to large compressive stresses in sputter deposited thin films is caused by the incorporation of tightly packed argon impurity atoms, achieved only at sufficiently high levels of argon ion bombardment and nickel adatom energies.
Anisotropic Electrical Transport and Surface Microstructure in GalnP2
Authors: Friedman D. J. , Kurtz S. R. , Kibbler A. E. , Bertness K. A. , Kramer C. , Matson R. , Arent D. J. , Olson J. M. 
Published: March 2011

ABSTRACTWe show that GaInP2 exhibits a directional anisotropy of the electrical conductivity when grown under the appropriate growth conditions. We relate this anisotropy to the characteristic surface microstructure of the material.
Study of Hall Effect and Magnetoresistance on a Novel Epitaxial FeSi Phase on Si(lll)
Authors: Onda N. , Sirringhaus H. , Steiner P. , Von H. 
Published: March 2011

ABSTRACTThe first magneto—transport data taken on thin pseudomorphic FeSi films with the CsCl structure are presented. FeSi appears to be a Kondo system with a Kondo temperature of TK ∼ 15 K. On air-exposed films which have not been protected by a Si-cap an ultrathin magnetic oxide is formed leading to large anomalies in the Hall effect and the magnetoresistance as the film thickness approaches 20 Å.
Microstructural Characterization of High-Pressure Oxidized Si1-x Gex /Si Heterolayers
Authors: David Theodore N. , Tam Gordon 
Published: March 2011

ABSTRACTSiGe alloys have recently been of interest for fabrication of heterojunction bipolar transistors using pre-existing or modified silicon-processing technology. These devices are faster than devices using pure silicon. Because of the interest in developing SiGe device structures, various elements of processing relevant to fabrication of the devices are being investigated. One such element has been the use of thermal oxidation for isolation of SiGe devices. Utilization of the technique requires an understanding of oxidation behavior of SiGe layers under a variety of oxidation conditions. Past studies in the literature have investigated the oxidation of SiGe at atmospheric pressure or at very high pressures (∼650–1300 atmospheres). The present study investigates the wet-oxidation of SiGe structures at intermediate pressures (∼25 atmospheres) and temperatures (∼750°C). Unlike atmospheric oxidation, most of the Ge (from SiGe) remains in the oxidized silicon (SiO2) in the form of GeO2. Occasional segregation of Ge to the oxidizing interface is noted. The microstructural behavior of partially and entirely oxidized structures is presented.
The Regularities of Selective Oxidation of Copper-Aluminium Solid Solutions.
Authors: Akimov A. G. , Melnikova N. A. 
Published: March 2011

ABSTRACTThe regularities of selective oxidation of copper solid solutions with 2–12 at.% aluminium have been studied by TEM, XPS and AES in combination with argon ion sputtering. It has been obtained that the increase of the aluminium concentrations in the solid solutions leads to the change of the oxidation mechanism. The internal oxidation of aluminium in Cu+(2–4at.%)Al results in the formation of the microincluslons of Al2O3 In the alloy. It has been demonstrated that the selective oxidation of aluminium in Cu+(12 at.%)Al results in the formation of uniform thin (<10 nm) aluminium oxide at the alloy surface. The kinetics of this alloy oxidation obeys the parabolic law.
Investigation of Titanium Silicon and Germanium Reaction
Authors: Aldrich D. B. , Sayers D. E. , Nemanich R. J. 
Published: March 2011

ABSTRACTIt has been shown that, across the full range of Si-Ge alloy compositions, C54 Ti(Siy Ge1-y)2 will form from the reaction of Ti with Six Gei1-x (0 ≥ x ≥ 1.00). X-ray Absorption Fine Structure (XAFS) and X-Ray Diffraction (XRD) have been used to define consistent labeling of the C54 lattice parameters. In C54 Ti(Siy Ge1-y )2 the Si and Ge atoms occupy sites equivalent to the Si sites in C54 TiSi2. The Si and Ge atoms form shells about the Ti atoms that, within error, have Si and Ge occupancies consistent with the net Si and Ge atomic percents as determine by Auger microprobe depth profiled compositional analysis. There is an increase in the Si/Ge ratio (i.e., y>x) in the Titanium Germanosilicide. This increase may be due, in part, to the relative diffusion rates of Si, Ge, and Ti. The morphologies of the reacted films can be divided into three groups based on their similarity to the morphologies of C54 TiSi2 and C54 TiGe2 formed from similar solid phase reactions. The morphological groupings indicate that the morphology of the final C54 phase (and probably the reaction path) is strongly related to the Si/Ge content of the film.
Potential Step Probes of Epitaxial Growth in Electrodeposited BCC Tl2O3 Films onto FCC Conducting Metal Oxides
Authors: Phillips Richard J. , Golden Teresa D. , Switzer Jay A. 
Published: March 2011

ABSTRACTPotential step transients were investigated as an in-situ probe of epitaxial growth for electrodeposited conducting metal oxides of the Tl2O3 and PbaTlbOc systems. Changes in the induction time and growth type were observed for Tl2O3 deposition as a function of the substrate. The substrates studied were glassy carbon and [210]-textured Pb0.8Tl0.2O1.9· T12O3 deposited onto the glassy carbon electrode showed a distinct induction time, the magnitude of which was potential dependent. Also the type of growth was characterized as three dimensional with instantaneous nucleation. X-ray diffraction of this film shows a nearly random pattern. The potential step transient for Tl2O3 deposited onto the [210]-textured Pb0.8Tl0.2O1.9, showed the absence of an induction time and elimination of the growth segment. The type of growth was characterized as two dimensional. X-ray diffraction indicated epitaxy was obtained for the Tl2O3 films which grew two dimensionally onto the [210]-textured mixed oxide.
Uniformity and Surface Properties of Diamond Films made by Tilted Oxyacetylene Combustion Flames
Authors: Zhu W. , Tan B. H. , Yin Z. , Ahn J. , Tan H. S. 
Published: March 2011

ABSTRACTHigh quality, transparent diamond films with relatively large deposition areas have been obtained from oxyacetylene combustion flames at the atmospheric pressure using nozzle tilted at an angle φ) with respect to the Mo substrates. These films are studied using scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. Experimental results show that the surface morphology and microstructure depend strongly on the processing parameters such as the gas mixture ratio of acetylene to oxygen, substrate temperature, and the nozzle angle φ. The uniformity of diamond films have been improved using this tilted combustion flame technique and some problems related with this approach are discussed.
Surface Behavior and Lattice Relaxation of SiGe/Si Strained Epitaxial Heterostructures
Authors: Chang Kevin H. , Ming Liaw H. 
Published: March 2011

ABSTRACTThe correlation between the surface morphology and the lattice relaxation in strained SiGe/Si heteroepitaxy has been studied. It is found that the surface crosshateched pattern develops as the strained epilayer thickness increases. The effect of thermal annealing and boron dopant level has also been studied. The result suggests that the crosshatched morphology on the surface is constituted by surface slip steps of glissile dislocation motion in the strained epitaxial growth processing.
Interface Structure and Defects in CVD 3C-SiC on (111) and (112) TiC Substrates
Authors: Chien Fen-Ren , Nutt S. R. , Buchan N. , Carulli J. M. , Beetz C. P. , Yoo W. S. , Cummings D. 
Published: March 2011

ABSTRACT3C-SiC, lattice-matched with TiC, is a candidate for use in wide-bandgap semiconductor devices. Epitaxial 3C-SiC films were grown on (111) and (112) TiC substrates, and defects were characterized by analytical TEM.
Mechanisms and Energetics of Surface Atomic Processes, an Atom-Probe Field ion Microscope Study
Authors: Tsong Tien T. 
Published: March 2011

ABSTRACTAtom-probe field ion microscopy is capable of imaging solid surfaces with atomic resolution, and at the same time chemically analyzing atoms selected by the observer from the atomic image. The samples are restricted to those having a tip shape, but in many cases this is no longer a drawback since structures in high-tech materials are reducing in size to that comparable to or smaller than the field ion emitter tip. This technique is finding many applications in different areas. Our recent applications of this technique to the study of the dynamical behavior of surfaces and surface atoms and their mechanisms and energetics, and the atomic scale chemical and composition analysis will be briefly described.
Atomic Arrangement of Al Near the Phase Boundaries Between √3×√3-A1 and 7×7 Structures on Si(111) Surfaces
Authors: Takaoka Katsuya , Yoshimura Masamichi , Yao Takafumi , Sato Tomoshige , Sueyoshi Takashi , Iwatsuki Masashi 
Published: March 2011

ABSTRACTScanning tunneling microscopy (STM) is used to study the structure of Al-√3×√3 domains on the Si(lll)-7×7 surface and the atomic arrangement near the domain boundary. Al-√3×√3 domains grow from the lower side of the <112> step and extend over the Si-7×7 terrace. The phase transition is observed to occur in units of the 7×7 size. Detailed investigation at around the boundary reveals that faulted halves of the 7×7 unit are adjacent to the boundary on the Si-7×7 side, while on the Al-√3×√3 side, Al adatoms occupy the T4 sites except for the rows adjacent to the phase boundaries where Al atoms occupy the Si adatom sites. The latter Al atoms play an important role to retain the dimer structure at the boundary.
Photoluminescence Intensity Enhancement of GaAs by Vapor-Deposited GaS: a Rational Approach to Surface Passivation
Authors: Jenkins Phillip P. , Hepp Aloysius F. , Power Michael B. , Macinnes Andrew R. , Barrontt Andrew R. 
Published: March 2011

ABSTRACTA two order-of-magnitude enhancement of photoluminescence intensity relative to untreated GaAs has been observed for GaAs surfaces coated with chemical vapor-deposited GaS. The increase in photoluminescence intensity can be viewed as an effective reduction in surface recombination velocity and/or band bending. The gallium cluster [(t-Bu)GaS]4 was used as a single-source precursor for the deposition of GaS thin films. The cubane core of the structurally-characterized precursor is retained in the deposited film producing a cubic phase. Furthermore, a near-epitaxial growth is observed for the GaS passivating layer. Films were characterized by transmission electron microscopy, X-ray powder diffraction, and X-ray photoelectron and Rutherford backscattering spectroscopies.
Iodine-Based dry Etching Chemistries for InP and Related Compounds
Authors: Pearton S. J. , Chakrabarti U. K. , Katz A. , Abernathy C. R. , Hobson W. S. , Ren F. , Fullowan T. R. 
Published: March 2011

ABSTRACTA comparison is given of the dry etching characteristics of InP and related materials in high ion density (>1011 cm−2 ) microwave discharges of HI, CH3I, C2H5I, C3H7I and C2H3I. The InIx species are more volatile than their InClx counterparts near room temperature and rapid etch rates can therefore be achieved without the need for sample heating. HI discharges provide faster etch rates than the halocarbon-based mixtures, but are more corrosive. All of these gas chemistries offer faster rates than conventional CH4/H2 mixtures. Halocarbon-iodide discharges still suffer from polymer deposition on the mask and within the reactor, as with CH4/H2. AES analysis shows an absence of contaminating residues with all of the iodine-based chemistries, and highly anisotropic features are obtained since the etching is driven by ion-enhanced desorption of the reaction products.
Characterisation of Wet Chemical Etching of Algaas Layers Using Dynamic Optical Reflectivity
Authors: Armstrong J. V. , Farrell T. , Turner G. 
Published: March 2011

ABSTRACTWet chemical etching of AlGaAs layers using a dilute mixture of ammonium hydroxide and hydrogen peroxide is monitored in real-time using dynamic optical reflectivity (DOR). The AlGaAs layers were grown as a multilayer reflector stack by chemical beam epitaxy (CBE). The reflectivity of a normal incidence 3 mW, 670 nm semiconductor diode laser is monitored during the etching process and analysis of the DOR trace gives the etch rate for the different etchant concentrations used.
Laser-Induced Selective Copper Deposition on Polyimides and Semiconductors
Authors: Hwang Seong-Don , Kher S. S. , Spencer J. T. , Dowben P. A. 
Published: March 2011

ABSTRACTIt has been demonstrated that copper can be selectively deposited on a variety of substrates including Teflon (polytetrafluroethylene or PTFE), Kapton (polyimide resin), silicon and gallium arsnide from solution by photo-assisted initiated deposition. A copper containing solution was prepared from a mixture of copper(I) chloride (Cu2Ci2) and decaborane (B10H14) in diethyl ether and/or THF (tetrahydrofuran). The copper films were fabricated by ultraviolet photolytic decomposition of copper chloride and polyhedral borane clusters. This liquid phase deposition has a gas-phase cluster analog that also results in copper deposition via pyrolysis. The approach of depositing metal thin films selectively by pholysis from solution is a novel and an underutilized approach to selective area deposition.
Surface Interaction Between Wf6 and GaAs Under UV Laser Illumination
Authors: Tabbal M. , Izquierdo R. , Meunier M. , Yelon A. 
Published: March 2011

ABSTRACTWe have studied laser-CVD of W on GaAs by X-ray Photoelectron Spectroscopy (XPS). Deposition of W is obtained by irradiating GaAs samples with a KrF excimer laser at normal incidence to the substrate, in a cell containing WF6 mixed with H2 and Ar. We have previously shown that WF6 and GaAs react at room temperature even without laser illumination. GaF3 formation and a loss of As were detected at the surface of the samples by XPS. At laser fluences of 50mJ/cm2, this reaction appears to be enhanced by laser heating of the substrate, but no metallic W is formed. At laser fluences of 67 mJ/cm2, metallic W begins to be deposited, through a pyrolytic dissociation reaction with the substrate.
Another Step in Developing a Single Wafer Integrated Process: Rapid Thermal Low Pressure Metalorganic Chemical Vapor Deposition of Local Diffused W(Zn) Contacts
Authors: Katz A. , Feingold A. , El-Roy A. , Moriya N. , Pearton S. J. , Rusby A. , Kovalchick J. , Abernathy C. R. , Geva M. , Lane E. 
Published: March 2011

ABSTRACTA selective deposition of W(Zn) metallization, for formation of diffused ohmic contacts onto InP-based material was realized by means of rapid thermal, low pressure metalorganic chemical vapor deposition (RT-LPMOCVD). The W(Zn) layers were deposited using a reactive gas mixture that contained diethylzinc (DEZn), WF6, H2 and Ar, at temperatures of 450 to 550°C and pressures in the range of 1–5 torr. Uniform andcontinuous layers of W(Zn), 30 to 120 nm thick, were obtained. These layers contained Zn at concentrations higher than 1×l018 cm−3, which was subsequentially in-diffused into the underlying semiconductor layer to form highly doped semiconductor layers as thick as 0.2μm. As a result, the specific contact resistance of the W(Zn)/ In0.53Ga0.47 As contact was reduced to minimum value of 5×l0−6 Ω·cm2. The W(Zn) film were found to be mechanically stable with a small compressive stress of 5.10−8 dyne. cm−2, and dry etch rates of up to 90 nmmin.
Surface Reaction Mechanisms Governing the Selective Area Growth of III-V Compound Semiconductors by Chemical Beam Epitaxy
Authors: Davies G J , Skevington P J , Levoguer C L , French C L , Foord J S 
Published: March 2011

ABSTRACTPrevious studies have helped elucidate the underlying mechanisms for selective area epitaxy in chemical beam epitaxy by investigating the reactions of triethylgallium (TEG) on a silicon nitride surface. However no explanation was produced as to why selective growth is lost at low temperatures or high Gp V beam fluxes. This question is addressed in this paper which examines the interaction between TEG and As2 on the silicon nitridesurface. In the absence of arsenic, TEG adsorbs with a low sticking probability on the dielectric. Adsorbed species mainly desorb rather than decompose, and any Ga produced on the surface becomes converted to a nitride form; no free Ga is produced hence GaAs growth cannot occur. Arsenic is found to form a weakly adsorbed phase on the nitride surface. Reaction with co-adsorbed TEG results in the formation of GaAs. Adsorbed As also is efficient in increasing the reactive sticking probability of TEG.The results provide further insight into the reaction mechanisms governing selected area epitaxy.
Aluminum CVD for Interconnect Thin Films
Authors: Speckman Donna M. 
Published: March 2011

ABSTRACTAluminum thin films were deposited by chemical vapor deposition on SiO2 substrates using trimethylamine alane (TMAA) in a standard low pressure CVD reactor system, with argon as a carrier gas. Film quality and morphology were found to be a sensitive function of reactor flow dynamics. High purity films were obtained with resistivities of ∼5.0 μΩ-cm and grain sizes of 1–2 μm in diameter, but many of these films also exhibited aluminum whiskers, which caused VLSI processing problems. The CVD aluminum films exhibited conformal deposition over 0.5μm topographies, and also demonstrated electromigration lifetimes comparable to those of sputtered aluminum films. Aluminum films deposited using TMAA were also found to be selective at 90°C for titanium oxide.
Influence of a RF Plasma on the Nucleation of Aluminum Using N-Trimethylamine-Alane (TMAA) as Precursor
Authors: Weber A. , Bringmann U. , Schiffmann K. , Klages C.-P. 
Published: March 2011

ABSTRACTAluminum films deposited on silicon with MOCVD methods generally exhibit a high surface roughness due to the hindered nucleation. To decrease the nucleation barrier a pretreat-ment of the wafer with TiCl4 vapor as a chemical activator is commonly suggested.This work examines the influence of a rf hydrogen plasma on the nucleation of aluminum onSi and SiO2 using TMAA as precursor.Atomic force microscopy (AFM) was used to determine the surface roughnesses and crystallite sizes of the aluminum deposits. Without plasma activation the nucleation barrier on Si(111) is substantially higher than on oxidized Si and therefore the pretreatment of the wafer plays an important role. The hydrogen plasma causes a substantial increase of the nucleus density leading to deposits with lower surface roughnesses compared to conventionalMOCVD aluminum. The influence of the substrate on the nucleation is almost “switched off” by the plasma activation and the grain sizes of Al on Si (111) and SiO2 differ only slightly. Relatively smooth films with a resistivity of 2.7 μΩcm are obtainable by employing a plasma activated nucleation step followed by a thermal MOCVD process. The increased nucleation rate is discussed in terms of kinetic effects of plasma activation.
Selectivity and Copper CVD From CuI β-Diketonates: Importance of Gas Phase Chemistry
Authors: Chiang C.-M. , Dubois L. H. 
Published: March 2011

ABSTRACTThe gas phase chemistry of CuI(hexafluroacetylacetonateXvinyltrimethylsilane),Cu(hfac)(vtms), was investigated using molecular beam techniques. Mass spectrometric and infrared spectroscopic data clearly show that Cu(hfac)2 is produced at nozzle temperatures in excess of 500 K. This result suggests that Cu(hfac)(vtms) undergoes a thermally induced disproportionation reaction in the gas phase to yield CuII (hfac)2, vtms, and atomic copper. As a consequence, copper CVD from CuIβdiketonates is deprived of its inherent selectivity.
Reactor Issues Important for the Deposition of Selective Tungsten by Chemical Vapor Deposition Using the SiH4 Reduction of WF6
Authors: Kotecki David E. , Colgan Evan G. , Rose Alan 
Published: March 2011

ABSTRACTWe have analyzed a single-wafer chemical vapor deposition (CVD) reactor used for the selective deposition of tungsten (W) by the silanc (SiH4) reduction of tungsten hcxafluoride (WF6). Results from a reactor model, which incorporates simplified heterogeneous reaction chemistry, arc compared to experimental data obtained from the same reactor to provide insight and understanding into reactor performance and define some of the trade-offs in the design of the reactor. A reactor for this process must provide: acold-wall temperature to suppress homogeneous reactions, a uniform wafer temperature to ensure uniform stress and resistivity in deposited films, and a uniform flux of SiH4 to the wafer surface to ensure uniform thickness of films. Maintaining a small internal volume in the reaction chamber was found to be beneficial for reducing both the quantity of rcactant gas at elevated temperatures and the residence time of the gas in the reactor, both of which lead to improved selectivity.