bluuebunny/crossref_metadata_2025_split huggingface dataset:
Donor Reactivation Kinetics and Hydrogen Redistribution in the Space Charge Layer of N-Type Silicon
Authors: Wu Y. -A. , Roos G. , Johnson N. M. , Herring C. 
Published: September 2012

ABSTRACTThe passivation and reactivation of As donor dopants in n-type Si was studied with both monatomic hydrogen and deuterium. Hydrogenated Schottky diodes were characterized with C-V and DLTS measurements. The reactivation kinetics of the As-H and As-D complexes were studied in the space-charge layer of reverse biased diodes in the temperature range from 60°C to 120°C. These bias-anneals yield dissociation time constants for As-H, from which an averaged activation energy of 1.17±0.1 eV was determined. Although the dissociation of the As-H complex is appreciably slower than that previously measured for P-H, the activation energy is within about 0.05 eV of that determined previously for the P-H complex (1.2 eV). The depth redistribution of the As-H complexes after bias-annealing agrees with the previous conclusion that hydrogen can assume a negative charge state in n-type Si.
The Effect of D-Defect in Silicon Single Crystal on Oxygen Precipitation
Authors: Fusegawa I. , Fujimaki N. , Yamagishi H. 
Published: September 2012

ABSTRACTWe investigated the effect of D-defect in CZ silicon single crystals on the oxygen precipitation by two-step thermal treatments consisting of the first annealing in nitrogen ambient at 1073K and the second annealing in dry oxygen ambient at 1273K. The density of D-defect was measured by counting ‘flow patterns’ using an optical microscope after preferential etching in Secco's solution for 30 minutes. It was found that the amount of oxygen precipitation along the growth axis was not affected by D-defect. The predominant factor of the oxygen precipitation after the two-step thermal process is the nuclei of oxygen precipitation generated around 723K during CZ crystal growth.
Effect of Fluorine on the Dopant Diffusion of Through-Oxtoe Implanted Boron in Si - a Correlation with Microstructural Defects
Authors: Huang J. G. , Lam A. , Jaccodine R. J. 
Published: September 2012

ABSTRACTIn case of boron through-oxide implant, it has been shown that the knocked-in oxygen atoms segregate at initially nucleated dislocation sites during the incubation and no significant junction movement is detected. The trapping of oxygen proceeds up to a certain time at which oxygen-precipitation occurs and this leads to an ejection of excess Si interstitials and further enhancing boron diffusion. However, with fluorine addition we believe that fluorine incorporation in SiO2 and/or SiO2/Si interface not only releases the strain gradient but also suppresses the silicon interstitials ejection and by this means suppresses the oxidation-enhanced boron diffusion. Correlated results of TEM microdefect structures and spreading resistance profiles are used to further support our postulation.
Interaction of Solute in Atoms with Dislocations in Lec GaAs
Authors: Burle-Durbec N. , Rakotobe A. , Pichaud B. , Minari F. 
Published: September 2012

ABSTRACTWe summarize here experimental results about moving dislocations and dislocations sources, in In-doped GaAs; several selective behaviours between α (As core in the glide set) and β dislocations are noticed. We try to correlate these observations with material structure and composition, and we propose a model of atomic interaction between In and α partial dislocations which could explain most of experimental observations. Some ideas about In diffusion are also developed.
Oxygen Precipitation Nonuniformity for Thermal History Around 723K During Cz Crystal Growth
Authors: Fusegawa I. , Yamagishi H. 
Published: September 2012

ABSTRACTWe investigated phenomena of oxygen precipitation nonuni-formity along crystal growth axis due to different thermal histories during CZ crystal growth. The oxygen precipitation process employed in this paper was two-step thermal treatments consisting of the first annealing in nitrogen ambient at 1073K for 4 hrs and the second annealing in dry oxygen ambient at 1273K for 16 hrs. The amount of the oxygen precipitation at the shoulder of a silicon single crystal was higher than the one at the tail end. We found this nonuniform distribution profile was due to the thermal history around 723K during crystal growth. Such an nonuniformity could be improved remarkably by adding a preannealing in dry oxygen ambient at 723K for 2 hrs before the two-step thermal treatment.
Characteristics of Oxygen Precipitation in Silicon Wafers Preannealed at 723K
Authors: Fusegawa I. , Iino E. , Hirohata T. , Yamagishi H. 
Published: September 2012

ABSTRACTWe investigated phenomena of oxygen precipitation in silicon single crystals by two kinds of thermal treatment, supposing a CMOS fabrication process. The one consisted of the first annealing at 1123K for 4 hrs and the second annealing at 1423K for 16 hrs. The other one consisted of the annealing at 1273K for 4 hrs and the second annealing at 1423K for 13 hrs. In the results, a single-step preannealing at 723K for 2 hrs was effective for the oxygen precipitation by the former process and nonuniform distribution profiles along crystal growth axis were well improved, however, insufficiently improved against the latter process. We considered a two-step preannealing process consisting of the first annealing at 723K for 2 hrs and the second annealing at 923K for 2 hrs. This new process was effective for the oxygen precipitation by the latter process. Especially, we could obtain uniform distribution profiles of oxygen precipitation along a crystal growth axis.
Stress-Related Defects in Implanted Locos + Trench - Isolated Structures
Authors: Vasquez Barbara , David Theodore N. 
Published: September 2012

ABSTRACTPoly-buffered local-oxidation of silicon + trench-isolation (PBLT) is a technique being explored for device isolation. In an earlier study, we had reported the presence of dislocations associated with a combination of high-dose (∼5E14 cm2) phosphorous implants and PBLT isolation. In the present study, the behavior of extended defects present in the structures is analyzed in greater detail. The origin and behavior of the defects is modelled to explore potential mechanisms to explain the observations. Implantation induced dislocation-loops interact with stress fields associated with PBLT isolation-trenches. Some of the implant loops (in the presence of a stress field) transform to dislocation sources which then create glide dislocations in the structures. Strategies for defect engineering are discussed, including reducing implant-induced damage (lowering the implant dose) or reducing stress fields (by moving the edge of the implanted region away from the trench). Defect densities can be reduced or eliminated.
Low Frequency Noise in Small MOS Devices
Authors: Uren Michael J. 
Published: September 2012

ABSTRACTRandom telegraph signals can be seen in the conductivity of submicron MOSFETs due to capture and emission from individual SiO2 defects. They show activated capture times, temperature dependent energy levels as well as a complex scattering behaviour. It is shown how 1/f noise in large MOSFETs arises naturally from the properties of these defects and how models based on this understanding can be constructed. 1/f noise is shown to be a poor tool for the study of the traps due to the loss of information associated with averaging over many active signals.
Mechanisms for N-Type Impurity-Induced Disordering of AlGaAs/GaAs Superlattices
Authors: Olmsted B. L. , Houde-Walter S. N. , Enrique Viturro R. 
Published: September 2012

ABSTRACTWe report on a study of disordering by the in-diffusion of a variety of Group IV and Group VI n-type impurities. Secondary ion mass spectroscopy, electrochemical C-V profiling, photoluminescence spectroscopy, and cathodoluminescence spectroscopy were used to determine the extent of interdiffusion, and the spatial distribution of impurities and native defects for impurity-induced disordering. In all cases, the n-type dopants enhance the Al-Ga interdiffusion coefficient over that due to an As overpressure of 2 atm alone. The Si-induced enhancement has been previously attributed to the change in Fermi level with doping and therefore should account for disordering using other n-type impurities. However, we observe important differences in the interdiffusion characteristics (diffusion rate, dopant profiles, energy and intensity of the deep-level emission) induced by Si or Ge, and that by S or Se. Whereas a strong correlation exists between the carrier concentration profile and the disordered regions in the Si-, Ge-, and Se-doped crystals, little direct correspondence is found for crystals doped with S. Instead, the disordering seems to be determined primarily by the presence of Group III vacancies, as is also the case in undoped crystals disordered by an As ambient alone. In addition, the deep level emission at 1.15 and 1.3 eV, which are associated with vacancy defects, correlates well with the extent of the Al-Ga interdiffusion.
Effect of Al Composition on the Deep Level Donors of AlxGa1-xSb/lnAs Single Quantum Wells
Authors: Lo Irai , Mitchel W. C. , Stutz C. E. , Evans K. R. , Manasreh M. O. 
Published: September 2012

ABSTRACTWe have performed Shubnikov-de Haas (SdH) measurements on the AlxGa1-xSb/InAs QW's with x from 0.1 to 1.0 under the negative persistent photoconductivity (NPPC) conditions and confirmed the prediction of Ionized Deep Donor model that the NPPC effect is a universal property for the materials containing ionized deep donors at low temperatures. The time-dependent recombination (electron capture) of the ionized deep donors is similar to that of DX centers. The saturated reduction of carrier concentration in the InAs well increases with increasing x, and rises steeply at about x=0.4. The concentration of deep donors which cause the NPPC in the AlxGa1-xSb/InAs QW's increases with the Al composition.
Gettering of Dissolved and Segregated Impurities in Multicrystalline Silicon Wafers
Authors: Stemmer M. , Perichaud I. , MartiNuzzi S. 
Published: September 2012

ABSTRACTPhosphorus gettering by diffusion from a POCl3 source was applied to matched wafers cut out of the same region of a cast ingot. Light Beam Induced Current mappings with wavelengths in the range between 840 and 980 nm lead to follow the variation of minority carrier diffusion length after gettering at 900°C for 120 and 240 mn, especially near extended crystallographic defects like dislocations and grain boundaries.The mappings show that after the gettering treatments, the local values of L increase due to the reduction of the recombination strength of extended defects and to the improvement of the homogeneous regions of the grains.As SIMS analyses indicate that Fe, Cu and Ni atoms are gettered, it is reasonable to assume that these impurities were initially dissolved in the grains and also segregated at the extended defects.
Spin Polarized Low Energy Electron Microscopy (Spleem) of Single and Combined Layers of Co, Cu, and Pd on W (110)
Authors: Poppa Helmut , Pinkvos Heiko , Wurm Karsten , Bauer Ernst 
Published: September 2012

ABSTRACTIn-situ recording of ultra-thin film growth by Low Energy Electron Microscopy (LEEM) results in accurate determinations of monolayer metal deposition rates for difficult to calibrate deposition geometries. Deposition rates and growth features were determined for Cu and Co on W (110) allowing for thickness control at the submonolayer level. Also, the transparencies of non-Magnetic overlayers of Pd (111) and Cu (111) to very low energy spin polarized electrons were compared and qualitatively explained by band structure considerations. Cu (111) is much more transparent than Pd (111) so that magnetic domain structures can be observed through at least 4 nmof Cu (111). This suggests the use of Cu (111) and other metals of suitable band structure as protective layers for surface magnetic studies.
Theory of the Negative Magnetoresistance in Magnetic Metallic Multilayers
Authors: Hood Randolph Q. , Falicov L. M. 
Published: September 2012

ABSTRACTThe Boltzmann equation is solved for a system consisting of alternating ferromagnetic -normal metallic layers. The in-plane conductance of the film is calculated for two configurations: successive ferromagnetic layers aligned (i) parallel and (ii) antiparallel to each other. The results explain the giant negative magnetoresistance encountered in these systems when an initial antiparallel arrangement is changed into a parallel configuration by application of an external magnetic field. The calculation depends on (A) geometric parameters (the thicknesses of the layers); (B) intrinsic metal parameters (number of conduction electrons, Magnetization and effective masses in the layers); (C) bulk sample properties (conductivity relaxation times); and (D) interface scattering properties (diffuse scattering versus potential scattering at the interfaces). It is found that a large negative magnetoresistance requires, in general, considerable asymmetry in the interface scattering for the two spin orientations. All qualitative features of the experiments are reproduced. Quantitative agreement can be achieved with sensible values of the parameters. The effect can be conceptually explained based on considerations of phase-space availability for an electron of a given spin orientation as it travels through the multilayer sample in the various configurations and traverses the interfaces.
Crystallographic Structure of Cobalt Films on CU (100)
Authors: Heckmann O. , Magnan H. , Le Fevre P. , Chandesris D. 
Published: September 2012

ABSTRACTThe stable structure of cobalt is hexagonal closed packed (hep), but cobalt can be stabilized in the face centered cubic structure (fee) by epitaxy on Cu (100). These films are ferromagnetic with [110] in plane easy axis. The Magnetic anisotropies of these films strongly depend on their structure, and in particular to the possible deviation from the isotropie fee structure. We have studied these films by surface EXAF.S. By recording the spectra both in normal incidence and in grazing incidence we have shown that the Co/Cu (100) films have a face centered tetragonal structure: the mean nearest neighbour distance parallel to the surface is 2.55 Å (same value as in bulk copper) and the interlayer bonds length is 2.50 Å (same value as in bulk cobalt). We conclude that the films are in perfect epitaxy on copper (100) with a contraction of the lattice parameter perpendicular to the surface of 4%. A constant tetragonalization is observed for films of 2 to 15 Monolayers.
Spin Wave Propagation and Brillouin Light Scattering on Antiferromagnetically Coupled Bilayers
Authors: Stamps R. L. , Camley R.E. 
Published: September 2012

ABSTRACTThe ground state spin configuration of antiferromagnetically coupled ferromagnetic thin films is determined by competition between anisotropies, interlayer exchange and the applied magnetic field. It is shown that many details of a ground state spin configuration can be obtained by studying the behavior of the spin wave frequencies as functions of propagation direction and applied field strength. A sensitive dependence on the relative film thicknesses is found for small applied field strengths.
Theory for the Nonlinear Magneto-Optical Kerr-Effect at Ferromagnetic Transition Metal Surfaces
Authors: Pustogowa U. , Hübner W. , Bennemann K. H. 
Published: September 2012

ABSTRACTThe nonlinear Magneto-optical Kerr-effect (NMOKE) has been proven to be an ultrafast spectroscopie probe of the magnetic and electronic properties of ferromagnetic surfaces. Extending our previous theory we calculate the linear and nonlinear Magneto-optical Kerr-spectra of Fe. The results for the nonlinear Kerr spectra are compared with recent experiments on a Fe (110) surface. We derive and discuss general features of the nonlinear Kerr-effect, especially the details of its dependence on exchange interaction and Fermi-level crossings in the Stoner picture and beyond, frequency, and spin-orbit interaction. Furthermore we demonstrate how various electronic material properties, such as d-band width, s-d hybridization or band narrowing due to electronic correlations or caused by geometry (reduced coordination number in thin films), can be extracted from the spectra. As an example, we compare the linear and nonlinear Kerr-spectra of Fe to those of Ni. The extension of our theory to the Kerr spectra of thin magnetic films films as well as of hidden magnetic interfaces occurring in sandwiches and multilayers is discussed.
Canted Magnetic Moments at the Gd (0001) Surface
Authors: Li Dongqi , Zhang Jiandi , Dowben P. A. , Garrison K. , Johnson P. D. , Tang H. , Walker T.G. , Hopster H. , Scott J.C. , Weiler D. , Pappas D. P. 
Published: September 2012

ABSTRACTWith spin polarized electron spectroscopies, we have investigated ordered Gd (0001) films deposited on W (110). The photoemission features of the gadolinium 5d surface state, the 4f levels, and the background exhibit considerable spin polarization along the same direction in the plane of the film, indicative of ferromagnetic coupling between the surface and the bulk. The 4f spin polarized photoemission data provides strong evidence that the surface 4f polarization differs from the bulk 4f polarization for Gd (000l). Our temperature dependent measurements with spin polarized secondary electron spectroscopy conclusively establishes that the surface of clean Gd (0001) possesses a perpendicular polarization component which persists to an enhanced surface Curie temperature. SMall amounts of contamination at the surface result in the disappearance of the perpendicular component and, therefore, a more perfect ferromagnetic coupling between the surface and the bulk.
In-Situ Magneto-Optical Kerr Effect of Epitaxial GD (0001)
Authors: Chappert C. , Weiler D. , Tang H. , Scott J.C. , Hopster H. , Pappas D.P. 
Published: September 2012

ABSTRACTWe have characterized magnetization loops of epitaxially grown Gd (0001) films on W (110) in the temperature range 145≤T≤300K. This was accomplished by measuring magneto-optical Kerr loops in UHV, in the transverse geometry, using a 2×10-4 deg sensitivity differential detector and He-Ne laser light.Films grown in the Stranski-Krastanov (SK) Mode (growth temperature 400°C) and films grown in a Frank-van-der-Merwe (FM) like Mode (growth temperature 20°C) behave significantly differently. While the room temperature grown films (FM) show square hysteresis behavior only after an annealing cycle to at least 300°C, the higher growth temperature (SK) leads to highly remanent films in the as grown state.The hysteresis behavior of these films is most important in conjunction with recently reported spin-polarized photoemission results, which showed that the growth temperature and therefore the film morphology has a strong influence on the surface magnetic reconstruction of Gd (0001) [1].
Growth, Structure and magnetism of Cobalt-Platinum Ultrathin Films and Sandwiches
Authors: Deville J.P. , Barbier A. , Boeglin C. , Carriere B. 
Published: September 2012

ABSTRACTCobalt-platinum alloys and multilayers are now well known for their potentialities in Magneto-optical recording Media. The growth of ultrathin layers and sandwiches is thought to be useful to find the relationship between the structural and magnetic properties at an atomic level. Low Energy Electron Diffraction (LEED) and Auger spectroscopy (AES) are used here to study the crystallography and the growth modes of Pt on Co (0001) surfaces. Co/Pt/Co sandwiches are also built and investigated by the same Methods. At room temperature we show the evidence of a good epitaxy of platinum on the Co (0001) surface leading to the possibility of obtaining ordered Co/Pt/Co sandwiches. Annealings at moderate temperatures lead to an epitaxial alloy formation. Auger results show that alloying indeed induces a magnetic moment on platinum atoms. This could explain the magnetic properties already observed in CO/Pt (111) Multilayers.
Spin Polarized Electron Spectroscopies of 3d and 4f Systems
Authors: Hopster H. 
Published: September 2012

AbstractRecent results from spin polarized electron spectroscopie studies of surfaces and ultrathin films are presented. The Magnetic coupling of 3d transition Metals (Cr,Mn) to the Fe (100) surface is studied by spin polarized electron energy loss spectroscopy. The first atomic layer of Cr and mn aligns antiparallel to the Fe. For larger thicknesses we find evidence for layer-by-layer antiferromagnetic order. In the range of 1–6 atomic layers the behavior is more complex with the surface of the Cr films showing preferential ferromagnetic alignment while the mn surface aligns antiparallel to the Fe substrate.Secondary electrons from Gd (0001) surfaces are shown to be highly spin polarized. However, no enhancement mechanism at low kinetic energy as in the 3d transition metals is observed indicating the absence of strongly spin dependent inelastic scattering in Gd. Temperature dependent spin polarized 4f photoemis-sion results show almost complete polarization demonstrating ferromagnetic surface coupling. However, a perpendicular surface magnetization component is found indicating surface spin canting. A large enhancement of the surface Curie temperature is also present.
Calculations of Bulk and Surface Magnetic Polaritons in Modulated Antiferromagnetic / Non-Magnetic Superlattices
Authors: Lacy Fred , Carter Ernest L. , Richardson Steven L. 
Published: September 2012

ABSTRACTRecent advances in molecular beam epitaxy have renewed research on the physics of artificially structured magnetic superlattices. In particular, there has been much theoretical research on the propagation of magnetic spin waves or magnetic polaritons in magnetic superlattices.1 In this work, we have studied the effect of modulating both the period of an antiferromagnetic/non-Magnetic semi-infinite superlattice and the relative thickness of its individual layers to see how the dispersion relationships co (k) for bulk and surface magnetic polaritons are effected. We have also calculated the effect of an external magnetic field on (u (k) and our calculation goes beyond the magnetostatic approximation by taking retardation effects into account.
Electrical and Optical Properties of Co Alloyed β-FeSi2 Formed by Ion Beam Synthesis
Authors: Panknin D. , Henrion W. , Wieser E. , Voelskow M. , Skorupa W. , Völise H. 
Published: September 2012

ABSTRACTBy subsequent implantation of iron and cobalt into silicon buried layers of semiconductinβ-(Fe1−xCox)Si2 are formed. The band gap energy as well as the spreading resistance decrease with increasing cobalt content. The microstructure of the sulicide layers is characterized by XTFM images.
On the Interface Structure of Buried CoSi2/Si(001) Layers and their Respective Schottky Barrier Heights
Authors: Wemer P. , Jäger W. , Schüppen A. 
Published: September 2012

ABSTRACTThis paper describes a high-resolution transmission electron microscope (HRTEM) study of the morphology and the atomic structure of CoSi2/Si(001) interfaces of continuous buried sulicide layers. These layers were produced by high-dose Co+ ion implantation and subsequent rapid thermal annealing. Planar interface regions of high perfection with domains of different atomic interface structure, and interface steps, frequently with I 111)I facets, were observed. There were significant differences in the interface structure between the upper and lower interfaces. Measuring Schottky barrier heights (SBH's) revealed different values for the upper (0.67eV) and lower (0.78eV) CoSi2/n-Si(001) interfaces. Possible correlations between the atomic interface structures and the resulting electronic properties are discussed.