bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Thermoelectric Power in Quantum Dots of Non-Parabolic Semiconductors in Thr Presence of a Classically Large Field
Authors: Ghatak Ktamkahya P. , De B. , Mondal M. , Biswas S.N. 
Published: March 2011

ABSTRACTWe have studied the thermoelectric power in quantum dots (QDs) of non-parabolic semiconductors in the presence of a classically large magnetic field and we have taken A3N B2V, ternary chalcopyrite, II-VI and III-V semiconductors. It is found that the thermopower increases with increasing film thickness and decreasing electron concentration respectively in all the cases. The numerical values are greatest for Cd3As2 and least for InAs and the theoretical results are in ageement with the experimental observation as reported elsewhere.
X-ray Study of Interdiffusion and Strain Relaxation in Annealed (SimGen)p Atomic Layer Superlattices
Authors: Baribeau J.-M. , Pascual R. , Saimoto S. 
Published: March 2011

ABSTRACTWe have studied interdiffusion and strain relaxation induced by annealing in (SimGen)p atomic layer superlattices grown by MBE using x-ray diffraction techniques. In these expertments, an interdiffusion coefficient Dλ. was determined by monitoring as a function of time, for annealing temperatures between 550° C and 700° C, the decay of the low angle first order 000 diffraction peak arising from the composition modulation wavelength ° of the superlattice. Strain relaxation was studied by measuring the angular shift of the superlattice 400 reflection on annealing. The strain was found to decrease exponentially and although most of the relaxation occurred within the first few minutes of annealing, residual strain was detected after several hours of heat treatment. During relaxation the low angle reflection peak intensity exhibited a rapid decay corresponding to an interdiffusion coefficient Dλ of the order of 5 × 10−23 m2s−1 at 700° C on structures grown on (100) Si with λ ≅ 1.5 nm. After most of the strain has been relieved, a slower linear decay rate was observed indicating a significant decrease of Dλ. The variation of Dλ with periodicity was explored and interdiffusion for structures grown on (100) Si and on Sil-xGex (0<x<l) buffers was compared.
Si/Ge Strained-Layer Epitaxy: Sil−xGex Alloy Buffer Layers and Ultra-Short Period SimGen Superlattices.
Authors: Ospelt M. , Henz J. , MÜller E. , KÄnel H. Von 
Published: March 2011

ABSTRACTSil−xGex alloy layers and ultra-short period SimGen superlattices on alloy buffer layers of the same concentration have been grown by MBE. The superlattices as a whole have been shown to have the lattice constant of the underlying alloy buffer layer, the individual Si and Ge layers being fully strained. Samples with a graded Ge content have been used to study the relaxation as a function of Ge content by means of X-ray diffraction and RBS and channeling.Transmission electron spectroscopy reveals that interface roughness is not simply statistical in these superlattices. Rather, electron diffraction shows additional features from a period doubling in the (111) directions, indicating that a corresponding interfacial ordering occurs. These features show 2- or 3-dimensional behavior depending on the thickness of the Si and Ge layers in the superlattices. Annealing studies show these features to persist even for annealing temperatures where the superlattices disintegrate into alloys.
Heteroepitaxial CxSil−X/Si(100) Metastable Alloys
Authors: Posthill J.B. , Rudder R.A. , Hattangady S.V. , Fountain G.G. , Humphreys T.P. , Nemanich R.J. , Parikh N.R. , Markunas R.J. 
Published: March 2011

ABSTRACTMetastable CxSi1−epitaxial films have been grown on Si(100) by remote plasmaenhanced chemical vapor deposition. Carbon concentrations of ∼ 3 atomic percent have been achieved at a growth temperature of 725 °C. No evidence for the formation or precipitation of SiC was found using x-ray diffraction, Raman scattering spectroscopy, IR. reflectance, or transmission electron microscopy. IR reflectance data gives a preliminary indication that the carbon has been incorporated onto substitutional sites in the Si lattice.
Growth of Epitaxial Layers of GexSi1−x BY UHV/CVD
Authors: Racanelli Marco , Greve David W. 
Published: March 2011

ABSTRACTUndoped epitaxial layers of GexSi1−x have been grown on (100) silicon substrates using the UHV/CVD technique. Epitaxial films were obtained at growth temperatures between 577 and 665 C. The growth rate and germanium content of the layers has been determined as a function of the germane flow and the deposition temperature. A bake at 800 C was found to be highly beneficial in reducing the defect density and improving the film roughness.
Heteroepitaxy and Characterisation Of Ge-Rich SiGe Alloys on GaAs
Authors: Venkatasubramanian R. , Timmons M.L. , Mantini M. , Kao C.T. , Parikh N.I. 
Published: March 2011

ABSTRACTGrowth of SiGe alloys on GaAs substrates at temperatures as low as 590 °C is described. The growth has been accomplished using the pyrolysis of disilane (Si2H6) and Germane (GeH4) at such temperatures. The layers were characterized electrically and show n-type conduction with a carrier concentration of ~ 1 × 1018 cm−3. The high quality of the SiGe layers are evident in the Rutherford backscattering (RBS) channeling results on SiGe/GaAs structures. A Xmin of 5.6% has been obtained for a Si0.05Ge0 95 layer on GaAs. Xmin increases with increasing silicon content in the SiGe layers. The SiGe alloy layers were studied by x-ray diffraction, and the composition was determined assuming coherent, but tetragonally-distorted growth of SiGe on GaAs. The distortion calculations, based on theoretical elastic-constants, were confirmed using Auger electron spectroscopy to check alloy composition.
Meso-Epitaxy: Epitaxial Growth Of Silicon Over Buried Single Crystal Cosi2 Layers.
Authors: Osenbach J. W. , White A. E. , Short K. T. , Praefcke H. C. , Kannon V. C. 
Published: March 2011

ABSTRACTBuried single-crystal layers of CoSi2 were formed in 150Ω-cm, p-type (100) silicon by high dose implantation of Co followed by furnace annealing. Subsequently, epitaxial silicon layers were grown over these buried CoSi2 layers using SiCl2H2 /HCI/H2. The RBS channel yield of the buried CoSi2 and the epitaxial Si layer is less than 4% indicating good crystallinity of the layer. The defect density in the epitaxial silicon layer as revealed by a dilute Schimmel etch, was in excess of 108 dislocations/cm2 which appear to originate from <111> CoSi2 facets. However, both the substrate/CoSi2 and the CoSi2/epi interface are single crystal as revealed by lattice fringes in TEM. To our knowledge, this is the first report of such a structure.
Formation of High Quality Si1−xGex/Si Heterostructures by Selective-Area Mbe Growth
Authors: Murakami Eiichi , Nishida Akio , Etoh Hiroyuki , Nakagawa Kiyokazu , Miyao Masanobu 
Published: March 2011

ABSTRACTSelective-area MBE growth of Si1−xGex film is examined using a Si substrate partially covered with SiO2 film. Elimination of misfit dislocations is observed by TEM. Two possible mechanisms in this elimination, limitation of the lateral extension of misfit dislocations, and partial relaxation of the strain at the SiO2 pattern edge, are discussed.
Columnar Epitaxy of Hexagonal and Orthorhombic Silicides on Si(111)
Authors: Fathauer R.W. , Nieh C.W. , Xiao Q.F. , Hashimoto Shin 
Published: March 2011

ABSTRACTColumnar grains of PtSi and CrSi2 surrounded by high-quality epitaxial silicon are obtained by ultra-high vacuum codeposition of Si and metal in an approximately 10:1 ratio on Si(111) substrates heated to 610-840°C. This result is similar to that found previously for CoSi2 (a nearly-lattice-matched cubic-fluorite crystal) on Si(111), in spite of the respective orthorhombic and hexagonal structures of PtSi and CrSi2. The PtSi grains are epitaxial and have one of three variants of the relation defined by PtSi(010)//Si(111), with PtSi[001]//Si<110>.
Structural Characterization of Ultrathin Epitaxial ErSi2−x on Si(111)
Authors: Kaatz F.H. , Spiegel J. Van der , Graham W.R. 
Published: March 2011

ABSTRACTThe epitaxial structure of ErSi2−x on Si(1 11) has been investigated using Rutherford backscattering (RBS) and transmission electron microscopy (TEM). Films 10 nm. thick show channeling minimum yields of 4% after room temperature deposition and annealing to 800°C. Plan view electron microscopy on ultrathin layers 0.5 nm. to 10 nm. thick reveals the formation of a complex microstructure involving vacancy ordering in these films. This superlattice structure is interpreted by considering domain formation and twinning in the heteroepitaxial ErSi2−x.
Surface Phase Separation and Ordering in Compound Semiconductor Alloys
Authors: Mcdevitt T.L. , Mahajan S. , Laughlin D.E. , Bonner W.A. , Keramidas V.G. 
Published: March 2011

ABSTRACTThe orientation dependence of phase separation has been examined in detail in InGaAsP layers grown by liquid phase epitaxy on (001), (110), (111)In and (123) InP substrates. It is shown that phase separation is two-dimensional in nature and does not occur along the growth direction for the cases examined. Further, phase separation takes place along the soft directions lying in the growth plane. These results very strongly suggest that phase separation evolves at the surface while the layer is growing.CuPt-type ordering characteristics of InGaAsP layers are presented. In addition, the Influence of growth temperature and growth rate on domain sizes have been investigated in GaInP2 layers. A model has been proposed to rationalize the formation of domains and involves steps present on the surface. Results suggest that ordering like phase separation occurs at the surface while the layers is being deposited. It is inferred that the two microstructural features evolve concomitantly at the surface during layer growth.
Optical Investigations of Symmetry Breaking in GaInP2
Authors: Mascarenhas A. , Kurtz Sarah , Kibbler A. , Olsonsolar J.M. 
Published: March 2011

ABSTRACTWe present experimental evidence for the spontaneous breaking of cubic symmetry in the band structure of films of Ga0 52 1n0 48P grown by organomeltallic vapor phase epitaxy on (100) GaAs substrates. We show how this effect is related to the spontaneous ordering of the alloy, and its correlation with the anomalous lowering of the band-gap observed in these films.
An Advanced Mechanical Dimpung Technique for the Preparation of TEM Specimens
Authors: Fischione Paul E. , Howe James M. 
Published: March 2011

ABSTRACTFor materials that are conducive to pre-thinning by mechanical techniques, a combination of dimpling and ion milling is commonly employed to produce TEM specimens. In order to minimize artifacts induced by ion milling and to provide an increased electron-beam transparent area, new instrumentation for mechanical thinning has been developed. Examples illustrating the utilization of this instrument in the preparation of cross-sectional interfaces from layered samples are discussed.
A Streamlined Technique for Preparation of Transverse Specimens for Transmission Electron Microscopy
Authors: Shaapur F. , Park M. 
Published: March 2011

ABSTRACTA procedure for batch processing of up to four specimens for cross-sectional transmission electron microscopy (X-TEM) has been developed. The technique is essentially an extension of the standard multi-slice composite full disc sample preparation method. However, disc cutting and dimple grinding steps have been eliminated. The trimming, gluing, stacking, and sectioning of the wafers from the original sample material to produce composite transverse sections are identical to those of the standard scheme. Grinding and polishing of the sections are carried out in a batch mode which, in turn, reduces the overall processing time per specimen. The prepared composite foils are mounted on metallic disc grids which provide structural support during ion thinning and microscopy.
A Procedure for Cross Sectioning Specific Semiconductor Devices for Both SEM and TEM Analysis
Authors: Benedict J. P. , Anderson Ron , Klepeis S. J. , Chaker M. 
Published: March 2011

ABSTRACTThe procedures described in this paper allow both SEM and TEM analysis to be performed on the same, device specific, semiconductor cross section. In order to accomplish this, a number of tools and fixtures have been constructed that allow the user to polish into the sample to a predetermined plane-of-polish, bisecting the device or feature of interest for SEM analysis. After SEM examination, the specimen is prepared for TEM analysis by first affixing a grid to the just-examined surface, inverting the specimen and parallel-polishing the backside of the specimen until the specimen's total thickness is in the 0.5 to 1.0μm range using the described tools. A subsequent one to ten minute ion milling step cleans the specimen. A very considerable positive side-effectof this method is the nearelimination of artifacts arisingfrom the use of strong chemicals and lengthy ion milling. The method has been extended to the preparation of plan-view device samples and non-semiconductor specimens.
Preparation of TEM Sections using Natural Lithography
Authors: Deckman H. W. , Dunsmuir J. H. 
Published: March 2011

ABSTRACTWe have developed and used a simple lithographic technique that allows preparation of TEM sections from a variety of materials in 10–45 minutes. To obtain TEM sections, 50–5,000 Å diameter cylindrical post structures are microfabricated on the surface of the sample using colloidal particles as an etch mask. The technique simultaneously prepares 104 – 108 posts. This not only allows a statistical characterization of sample structure but also provides enough material for studies of the electronic, spectroscopic and chemical properties of edge sites exposed on the post surfaces. These lithographically prepared posts have been used to study the structure of materials as diverse as a layered transition metal chalcogenide catalysts, semi-insulating polysilicon, amorphous semiconductor superlattices, crystalline metallic and semiconductor superlattices, and molecular-scale microporous superlattices.
Preparation of a Prespecified Interfacial Region by Cross Section Sampling for HREM Investigations
Authors: Paul-Henri Albarede 
Published: March 2011

ABSTRACTThin polysilicon layers are used in microelectronics as a first metal level. With careful annealing, a doped polysilicon layer can also act as a diffusion source for the underlying Si substrate. For such a case, the quality of the polysilicon to substrate Si interface plays an important role in the electrical and migratory properties of the final structure. Therefore, the interface must be observed very closely.Arsenic doped polysilicon was deposited on a <001> oriented Si wafer. Cross-section TEM specimen preparation was performed by first cutting dices centered on the prespecified region of interest. The dices are bounded face to face, and then a parallel double face mechanical polishing of the section reduces the thickness of the cross-section to about 30 microns. An ion milling operation is used to finish the preparation. Localisation precision by this method is not better than 100 microns, but this can be improved to 10 microns by replacing one of the dices with a piece of glass to allow visualization of the surface during polishing.The advantage of this method is that a large region can be observed, 1.5 mm long on each piece, with rather good localisation.An application is the HREM imaging of a typical interfacial region. We could see an ultrathin (1nm) amorphous layer running along the interface between the Si and the polysilicon. Physical characterization (EDXS, EELS) was obtainable from this ultrathin layer.
Magnetic Recording Disk Specimen Preparation for Transmission Electron Microscopy
Authors: Parker Michael A. , Parker K. L. , Meininger M. , Bermea A. 
Published: March 2011

ABSTRACTModifications to conventional techniques required to prepare specimens from magnetic recording disks are described. Both the preparation of through-foil and cross-section specimens are discussed. The differences between preparation techniques for particulate and thin film disks are elucidated. Micrographs of specimens prepared by various techniques from both types of disk technology are presented that show the relative merits of these methods.
Diffuse X-Ray Scattering for the Study of Defects in Silicon
Authors: Larson BC , Barhorst JF 
Published: March 2011

ABSTRACTX-ray diffuse scattering can be used to study the size, concentration, and nature of lattice defects and defect clusters in crystalline materials. The availability of analytical models and detailed numerical calculations for the “Huang” diffuse scattering close to Bragg reflections and the “asymptotic” diffuse scattering at somewhat larger distances from Bragg reflections has made it possible to carry out detailed analyses of the intensity and angular distribution of the diffuse scattering in terms of specific defect parameters. Accordingly, diffuse scattering has been used to study point defects, dislocation loops, and precipitates in metals, semiconductors, and insulators and has provided information on defect geometries, size distributions, and concentrations. In this paper, the theoretical framework necessary for the interpretation of the “Huang” and “asymptotic” diffuse scattering from defect clusters is presented and examples of diffuse scattering calculations for defects in silicon are given. Diffuse scattering from clustered defects in silicon is discussed in terms of the type of information available from this scattering and the relative merits of diffuse scattering as an investigative tool for defect clusters. Diffuse scattering analysis techniques for the determination of separate size distributions for vacancy and interstitial dislocation loops in silicon are presented and applied to diffuse scattering measurements on neutron irradiated silicon. Dislocation loop densities and sizes determined in the as-irradiated state and after thermal anneals are compared with electron microscopy results.
A Tentative Identification of the Nature of {113} Stacking Faults in Si – Model and Experiment
Authors: Tan T.Y. , Foell H. , Mader S. , Krakow W. 
Published: March 2011

ABSTRACTAn atomic model with fully bonded interstitial atoms is proposed for the {113} stacking faults (SF). It is shown that the development of the {113} habit plane is a result of minimizing bond length changes. The fault may be represented by a partial dislocation and a partial will facilitate an unfaulting reaction to result in a edge dislocation. Lattice images were obtained for a {113} SF which showed that the model is essentially correct.
Formation and Effects of Secondary Defects in Ion implanted Silicon
Authors: Washburn Jack 
Published: March 2011

ABSTRACTThe clustering of isolated interstitial silicon, implanted atoms, and vacant lattice sites produced by low temperature and room temperature ion implantation during subsequent annealing is reviewed. An electron microscope method for studying the kinetics of the amorphous to crystalline transformation in silicon is described. The technique is applied to measurement of the activation energy for interface migration and the formation of microtwins for different growth directions. A very brief review of the effects of laser annealing after ion implantation is included.
A Review of Ntd-Induced Defects in Silicon
Authors: Meese J. M. 
Published: March 2011

ABSTRACTNeutron transmutation doping (NTD) has become the preferred method of phosphorus doping of float zone silicon for the Si power device industry. This doping process is accomplished by thermal neutron irradiation in a nuclear reactor. One of the stable isotopes, 30Si, is transmuted to the desired dopant, 31p, by thermal neutron capture and beta decay. This transmuted product becomes electrically active only after suitable annealing of the accompanying radiation damage which is the result of a number of different displacement mechanisms. This paper will present a review of our present understanding of the production and annealing of these displacement defects.
Dislocation Defect States in Deformed Silicon
Authors: Patel J. R. , Kimerling L. C. 
Published: March 2011

ABSTRACTTransient junction capacitance measurements on deformed silicon reveal a variety of states after deformation. Upon annealing or following more homogeneous deformation the defect spectrum shows a single broad feature. A state at E(0.38) has been tentatively assigned to defect sites along the dislocation. A broad band of states at H(0.35) is postulated to represent states due to the reconstructed dislocation core.
Swirl Defects in As-Grown Silicon Crystals
Authors: de Kock A.J.R. 
Published: March 2011

ABSTRACTDuring melt-growth of macroscopically dislocation free bulk silicon crystals (floating-zone and Czochralski technique) microdefects can form due to the condensation of thermal point defects (self-interstitials, vacancies). The formation of these imperfections, generally referred to as “swirl defects”, is strongly affected by the growth conditions (e.g. the crystal pulling rate) and crystal purity. The various reported defect formation models will be discussed. Special attention will be paid to the effect of doping on swirl defect formation.
Oxygen, Oxidation Stacking Faults, and Related Phenomena in Silicon
Authors: Hu S. M. 
Published: March 2011

ABSTRACTSome salient features of the phenomena of oxidation stacking faults (OSF) and oxidation enhanced diffusion(OED) are summarized, and some theories of OSF growth are critiqued. Then a new theory is developed which shows the growth to be reaction controlled, and the retrogrowth to be naturally a regime in the entire OSF growth process. The theory has provided an estimated bound on the activation energy of self-diffusion in silicon. It is shown that the observed power law growth kinetics can be explained quite naturally by a bimolecular annihilation process of the excess self-interstitials. A possible physical model of such an annihilation process is discussed. A number of phenomena related to the nucleation of oxygen precipitates in silicon are reported. Then a model of nucleation is presented which is shown to be consistent with all observed phenomena.In this model, the homogeneous nucleation proceeds not merely via the agglomeration of oxygen atoms, but in combination with small vacancy clusters. Evidence from the OSF and OED phenomena, and the nucleation of oxygen precipitates thus necessitates the dualism of vacancies and interstitials as thermal defects in silicon at high temperatures.
Enhanced Diffusion and Formation of Defects During Thermal Oxidation
Authors: Narayan J. , Fletcher J. , Appleton B. R. , Christie W. H. 
Published: March 2011

ABSTRACTEnhanced diffusion of dopants and the formation of defects during thermal oxidation of silicon has been investigated using electron microscopy, Rutherford backscattering, and secondary ion mass spectrometry techniques. Enhanced diffusion of boron was clearly demonstrated in laser annealed specimens in which secondary defects were not present. In the presence of secondary defects, such as precipitates, enhanced diffusion of boron was not observed. The absence of enhanced diffusion during thermal oxidation was also observed for arsenic in silicon. The mechanisms associated with thermal–oxidation enhanced diffusion are discussed briefly.