bluuebunny/crossref_metadata_2025_split huggingface dataset:
Furnace and Rapid Thermal Annealing of P–Implanted Silicon for Solar Cell Fabrication
Authors: Harrison H.B. , Lee Y.H. , Pogany A. , Kenny M.J. 
Published: March 2011

ABSTRACTSingle crystal silicon has been implanted with low energy (20 keV) phosphorus ions and a comparison made of furnace annealing (which produces excellent solar cells) and rapid annealing using a radiant incoherent light source. The light source is used to anneal and activate implanted layers in the isothermal mode on a time scale of the order of seconds compared with the much longer furnace annealing times of several hours.Initial results using the incoherent light source show a high dark current and inferior photoresponse. However a subsequent thermal treatment at 600°C for 10–15 minutes shows that the resultant photoresponse can approach that of the longer time furnace anneal. Transmission electron microscopy shows the formation of large voids (20–100 nm) after the initial annealing phase. These reduce in size after furnace annealing. This photoresponse may be related to this void formation.
Structural Characterization of Dynamic Annealing Effects of P+ Implanted SI
Authors: Berti Marina , Drigo A.V. , Gabilli E. , Lotti R. , Lulli G. , Merli P.G. , Antisari M. Vittori 
Published: March 2011

ABSTRACTSome renarks about the mechanism for dynamic annealing during high dose rate P implantation of Si are reported. TEM observations and RBS channeling measurements show that the ion bombardment enhances the amorphous to crystalline transformation in the temperature range 200 ≤ T ≤ 600°C. It is found that the ratio between the observed recrystalli-zation velocity and the thermal SPE velocity decreases with increasing temperature. This indicates that a transition temperature must exist between the ion-assisted recrystallization regime and the ?lermal SPE regime. For the energy (100 keV) and the dose rate (60,uA/cm2) used in our experiments the transition temperature is about 700°C.
Electronic and Magnetic Properties of Interstitial 3d Impurities in Silicon
Authors: Katayama-Yoshida H. , Zunger Alex 
Published: March 2011

AbstractSelf-consistent spin-unrestricted all-electron Green's function calculations are reported for the first time for a series of interstitial 3d impurities in silicon. The calculations, performed within the selfinteraction- corrected local-spin-density fromalism show: (i) not all 3d impurities follow Hund's rule: Tio, Ti−, Vo, V+ and Co2+ have a low-spin ground state, (ii) the angular momentum part gL of g-value is quenched due to p-d hybridization effects, (iii) covalency explains also the chemical trends in the central hyperfine coupling constants, (iii) chemical trends in donor andacceptor transitions are reproduced and are consistent with a high-spin to lowspin transition at the low-Z end and high-Z end of the 3d series, (iv) A number of predictions are offered.
Identification of Chalcogen Defects in Silicon
Authors: Beeler Franz , Scheffler Matthias , Jepsen Ove , Gunnarsson Olle 
Published: March 2011

AbstractWe show how self-consistent total-energy calculations can be used to identify the position of defects in semiconductors. Despite intensive experimental research on S, Se and Te point defects in Si, it has remained unclear whether these impurities occupy substitutional or Td-interstitial sites. Our Green-function total-energy calculations show that the substitutional site is favored by several eV and therefore the stable defect position is identified as substitutional. We further consider the formation energies of distant defect pairs consisting of a substitutional chalcogen and a Si self-interstitial and we study the reaction where the two constituents change places.
Microscopic Identification of Defects in Semiconductors by Electron-Spin-Resonance and Related Techniques
Authors: Schneider Jorgen 
Published: March 2011

AbstractThis talk will review and compare very basic intrinsic and extrinsic paramagnetic defect structures which are characteristic for group IIB-VI, III-V and elemental semiconductors. The case of cation vacancy related defects in ZnS and ZnSe, that of antisite defects in GaP and GaAs and that of deep impurity donors in IIB-VI semiconductors and silicon will be treated as representative examples, thus illustrating the possibilities (and limitations) of the ESR technique.
Characterization of Semiconductors and Semiconducting Superlattices Using High-Resolution Photoluminescence Spectroscopy
Authors: Reynolds D. C. , Bajaj K. K. , Litton C. W. 
Published: March 2011

AbstractHigh resolution photoluminescence for the identification of impurities and defects in semiconductors has emerged as a powerful technique. We review the technique with emphasis on GaAs realizing that it is applicable to many different semiconductor materials. The binding energies of thle ground state and of several low-lying excited states of the impurity centers are determined by studying the radiative transitions associated with excitons bound to neutral donors or acceptors. Recent developments in the studies of GaAs-AlGaAs multi-quantum-well (MQW) structures using high resolution photoluminescence are also reported. Variations of the energies of the various transitions in MQW structures as a function of well size are presented. Estimates of the interfacial quality in these heterostructures are made from line shape analysis.
Growth of (110) GaAs/GaAs by Molecular Beam Epitaxy
Authors: Parechanian L.T. , Weber E.R. , Hierl T.L. 
Published: March 2011

AbstractThe simultaneous molecular beam epitaxy (MBE) growth of (100) and (110) GaAs/GaAsintentionally doped with Si(∼lE16/cm^3) was studied as a function of substrate temperature, arsenic overpressure, and epitaxial growth rate. The films wereanalyzed by scanning electron and optical microscopy, liquid helium photoluminescence (PL), and electronic characterization.For the (110) epitaxal layers, an increase in morphological defect density and degradation of PL signal was observed with a lowering of the substrate temperature from 570C. Capacitance-voltage (CV) and Hall Effect measurements yield room temperature donor concentrations for the (100) films of n∼l5/cm^3 while the (110) layers exhibit electron concentrations of n∼2El7/cm^3. Hall measurements at 77K on the (100) films show the expected mobility enhancement of Si donors, whereas the (110) epi layers become insulating or greatly compensated. This behavior suggests that room temperature conduction in the (110) films is due to a deeper donor partially compensated by an acceptor level whose concentration is of the same order of magnitude as that of any electrically active Si. Temperature dependent Hall effect indicates that the activation energy of the deeper donor level lies ∼290 meV from the conduction band. PL and Hall effect indicate that the better quality (110) material is grown by increasingthe arsenic flux during MBE growth. The nature of the defects involved with the growth process will be discussed.
Optically Detected Magnetic Resonance of Copper Doped Gallium Phosphide
Authors: Gislason Haflidi P. , Watkins George D. 
Published: March 2011

AbstractA deep photoluminescence (PL) band peaking at 1.08 eV in Cu-doped GaP has been studied by means of optically detected magnetic resonance (ODMR). We report an intense S=l ODMR spectrum arising from this PL band. The signal is strongly anisotropic and consistent with a center of triclinic symmetry. Some of the ODMR transitions show a well resolved hyperfine structure in agreement with the nuclear spin I=3/2 of Cu, thus suggesting the presence of Cu in the defect.
Defect Identification in High-Purity Semiconductors
Authors: Haller Eugene E. 
Published: March 2011

AbstractThe elemental semiconductors silicon and germanium can be purified to electrically active impurity concentrations as low as ∼1010cm−3. Highly sensitive, energy dispersive analytical techniques have been developed to identify and measure the concentration of the residual elemental impurities. The application of these techniques to very pure materials has also resulted in the discovery of a large number of new levels which are due to impurity/defect complexes. Photothermal ionization spectroscopy using uniaxial stress or a magnetic field, electron paramagnetic resonance, and doping experiments using stable and radioactive elements have been used in combination to identify the composition and the structure of some of the new centers.
Microscopic Identification of Optical Defects in Silicon by Photoluminescence
Authors: Sauer R. 
Published: March 2011

AbstractThe paper reviews isotope effects observed in the photoluminescence (or absorption) of deep defects in silicon introduced by irradiation damage, heating, quenching or during crystal growth. Three examples are discussed in more detail where photoluminescence methods, partially in combination with other analytical methods, have led to microscopic defect models.
Dangling Bonds and Sub-Gap Optical Absorption in Silicon
Authors: Seager C. H. , Lenahan P. M. , Brower K. L. , Mikawa R. E. 
Published: March 2011

AbstractThe silicon “dangling bond” defect plays a large part in controlling the electronic properties of a-Si, polycrystalline silicon, and the Si/Si0 2 interface. Jackson et al. have suggested that transitions of electrons occupying this defect produce the Urbach-like sub-gap absorption tail seen in two of these materials. We have performed optical and electron spin resonance measurements on polycrystalline silicon, plastically deformed silicon, and Si/Si02 interfaces to further examine this contention. In addition to seeing no measurable absorptance due to dangling bond interface states in the latter system, we conclude from the poor correlation of ESR signals with optical data that the Urbach tail in polycrystalline and deformed silicon is not due to transitions of dangling bond electrons.
A Relationship Between Interatomic Bonding and Electron Transport in Plasma–Deposited, Amorphous Metal Alloys
Authors: Pike G. E. , Hays A. K. , Nelson G. C. , Fritz I. J. 
Published: March 2011

ABSTRACTAmorphous metal alloy films have been produced using a new technique. Nominally NiP alloys are made by dissociating mixtures of nickel carbonyl and phosphine using a radio-frequency discharge in either an argon or a hydrogen carrier gas. This process incorporates significant amounts of carbon and oxygen impurities into the film. A previously unreported relationship between the interatomic bonding involving these impurities and the electronic transport properties of the films is discussed in this paper. The bonding studies were carried out principally using Auger lineshape analysis. Transport properties measured included 4-terminal resistivities, Hall mobilities and carrier concentrations, and Seebeck coefficients. Covalent bonding of Ni with C or P with O is strongly correlated with high resistivity, mainly through a decrease in carrier density.
Thermodynamic Considerations in Thin-Film Metallizations
Authors: Beyers Robert 
Published: March 2011

ABSTRACTThe drive to produce smaller devices in integrated circuits is wellknown. Concurrent with this drive is the need to incorporate new materials, such as silicides, as interconnects, diffusion barriers, and contacts. During circuit fabrication, these materials are in contact with other solids and gases at elevated temperatures. Consequently, reactions may occur which degrade the materials present. Since the reactions of interest typically involve three elements distributed in several phases, ternary phase diagrams are required to predict the occurrence of a reaction and the subsequent reaction products, or, conversely, the stability of the phases present. Hence, ternary diagrams can provide important guidance in the selection of optimal materials and the design of reliable processing schedules.
Film Stress in Pd2Si Layers of Varying Thickness
Authors: Coulman Betty , Chen Haydn , Ritz Kenneth 
Published: March 2011

ABSTRACTLittle is known about the development of film stresses in very thin films (thicknesses of the order of a few hundred Angstroms or less). As interest intensifies in the technological application of ever smaller quantities of materials, the behavior of very thin. films will undergo increasing scrutiny. In this study, the film stresses in evaporated Pd films and Pd2Si films formed by reaction with the Si substrates at 250°C were measured for thicknesses ranging from 7 to 107 nm. Stresses were calculated from the substrate radii of curvature determined by X-ray diffraction topography techniques (Lang and double crystal) and Stoney's equation. Because film continuity cannot be taken for granted at low coverage, the films were examined by electron microscopy in an attempt to correlate their morphology with the observed stresses.
Photoconductivity of Boron Doped A—SiN X:H
Authors: Nojima H. , Hayakawa T. , Imada E. , Kojima Y. , Narikawa S. , Matsuyama T. , Ehara S. 
Published: March 2011

AbstractThe photoconductivity of boron doped a—SiNx:H(x=O.07)has been studied by steady state secondary photocurrent, xerographic photodischarge, the time of flight measurement, and ESR. The dominant carrier of the photocurrent in a—SiNx:H is found to be electron. The μτ product of the electron decreases with increasirg doping amount of boron, while that of the hole increases and becomes largerthan 10-8cm2/V. From these results it is found that the life time of the hole becomes longer with increasing the amount of doping boron. The intensity of the ESR signal due to the neutral dangling bonds decreases monotonically with doping boron, and this decrease of the neutral dangling bond density is considered to be due to not only change of the occupation statistics, but mainly to the chemical or electrical interaction between boron and nitrogen.
Enhanced Stability of Amorphous Silicon Pin Solar Cells by Doping Profiles
Authors: Moeller M. , Kausche H. , Guenzel E. , Juergens W. , Stetter W. 
Published: March 2011

Abstractpin cells with the light entering the n-layer (pinITO) or the p-layer (SnO2p(C)in) were prepared taking into account the ‘basic’ boron profile in the i-layer. Their efficiencies (up to 7.4% and 10.1%) show a light-induced degradation. This can be removed by doping the i-layer of pinITO cells with a decreasing boron profile. The initial efficiency is only slightly affected. Cells containing fluorine due to prior plasma-etching require higher amounts of boron for stability. For the cell type SnO2p(C)in, phosphorus profiles, however increasing towards the n-layer, lead to reduced cell degradation without affecting the efficiency. The results of profiling were interpreted in terms of a recombination model.
Amorphous Silicon Thin Film Transistors and Memory Devices
Authors: Lecomber P.G. 
Published: March 2011

AbstractThe preparation of amorphous silicon with a low density of defect states by the glow discharge decomposition of silane and the ability to control its electrical conductivity over many orders of magnitude by the addition of phosphine or diborane to the silane, stimulated a worldwide interest in this material and in its possible applications. This paper begins with a description of the preparation technique and a brief review of some of the important properties of the material. The fabrication and characteristics of a-Si thin-film field effect transistors will be described and followed by a discussion of the applications of these devices in large area liquid crystal displays, in simple logic circuits and in addressable image sensors. Finally, the use of a-Si in memory devices will be briefly described.
An Active Matrix Liquid Crystal Display Using a Novel Amorphous Silicon Switching Device
Authors: Boer W. Den , Payson J.S. , Skebe G. , Swartz L. , Yaniv Z. 
Published: March 2011

AbstractA 32×32 pixel liquid crystal display using amorphous silicon n-i-n diodes as switching elements has been developed. The display can be operated at duty ratios up to 1:256.
High Deposition Rate Amorphous Silicon Alloy Xerographic Photoreceptor
Authors: Hudgens S.J. , Johncock A.G. 
Published: March 2011

AbstractA new multilayer amorphous silicon alloy photoreceptor has been deposited at rates exceeding 36 µm/hr. using 2.45 GHz microwave glow discharge. The device whose structure is Al/a-Si:H:F (B-300)/a-Si:H:F (B-10)/a-Si:H:F:C is deposited in a powderless plasma deposition process which exhibits gas utilization efficiency approaching 100%. The xerographic performance of a 28µm device is: Vsat∼1100 V for a +7 KV corona; dark half decay time ≃5 sec; and photosensitivity ∼0.3 µJ/cm2 at λ = 650 nm. Stable, high quality xerographic images are obtained with these photoreceptors.
Transient Photoconductivity Studies of a-Si:H Interfaces
Authors: Street R. A. 
Published: March 2011

AbstractThe application of transient photoconductivity to the study of contacts and interfaces with a-Si:H is reviewed. The photocurrent is shown to contain three terms - one from the drift of photogenerated carriers, and two from contact and bulk effects due to the electric field induced by the drifting carriers. For different sample configurations, each of these terms can dominate, and each gives different information about a-Si:H bulk or surface electronic properties. The effects are illustrated with data from metal contacts, dielectric interfaces, doped layers and gap cell measurements.
Electronic States Associated with Grain Boundaries in Silicon
Authors: Shyu C. M. , Cheng L. J. 
Published: March 2011

ABSTRACTThe density of states at the grain boundary is found to be a complicated function of both the defect state property and the physical location of the defect at the boundary. A modified double-depletion-layer model concerning the nonuniform distribution of defects along the boundary is presented. A method is developed which can estimate the level location from the complex DLTS spectra.
Electronic Structure of Grain Boundaries and Interfaces in Polycrystalline Zinc Oxide
Authors: Sukkar M. H. , Tuller H. L. , Johnson K. H. 
Published: March 2011

ABSTRACTPreliminary theoretical models for the electronic structure of grain boundaries and interfaces in polycrystalline ZnO have been constructed on the basis of self-consistent-field X-alpha scattered-wave (SCF-Xα-SW) cluster molecular-orbital calculations. The disposition and character of the interface states, relative to the valence and conduction bands of the otherwise perfect crystalline material, have been studied for clusters representing coordinatively unsaturated Zn surface sites and molecular O2 chemisorption thereon. The possible effects of the resuiting interface states on electron transport at grain boundaries in ZnO varistors have been addressed.
Charge Collection Characterization of Polycrystalline n-GaAs Layers for Solar Cells
Authors: Paz O. , Bhat K. N. , Borrego J. M. 
Published: March 2011

ABSTRACTN–type Ga-As polycrystalline layers, grown on Mo substrates by the metal-organic process were investigated using the SEM. Micrographs of charge collection contrast indicate a fairly random distribution of high collection (bright) grains. In a typical cell about 1/3 of its area is bright, with nonuniformities in collection current within and between grains. These results correlate well with Isc measurements, and some of the variations betweencells is explained in terms of insufficient doping of the grain boundaries.Reducing the penetrating depth of the carriers' excitation volume results in lowering of the collection current. The measurements were normalized for changes in beam and EBIC current by a comparison with a single crystal cell of the same geometry. This degradation is explained in terms of contamination or damage of the layer close to the surface during growth.
Grain Boundaries in Crystallized Silicon Thin Films
Authors: Johnson N. M. , Biegelsen D. K. , Moyer M. D. 
Published: March 2011

ABSTRACTThe presence of residual grain boundaries in laser-crystallized thin films of silicon necessitates an understanding of their properties and effects on device operation. In CW laser crystallized silicon islands, lateral p-n junction diodes have been used to evaluate the following: (1) enhanced arsenic diffusion along grain boundaries, (2) current-voltage characteristics, and (3) effects of hydrogenation on diode operation. To study the process of hydrogen passivation, deuterium has been used as a readily identifiable isotope which duplicates hydrogen chemistry. From secondary-ion mass spectrometry, diffusion of deuterium in single-crystal and polycrystalline silicon at low temperatures (e.g., 350 C) clearly demonstrates that grain-boundary diffusion dominates bulk diffusion.
Characterization of Grain Boundaries in Electronic Ceramics by Transmission Electron Microscopy
Authors: Clarke David R. 
Published: March 2011

ABSTRACTThe principal high resolution transmission electron microscopy techniques used in characterizing grain boundaries in electronic ceramics are described, including those recently developed for detecting the presence of extremely thin (∼10Å) intergranular phases. The capabilities of the techniques are illustrated with examples drawn from studies of ZnO varistors, PTC BaTiO3 devices and boundary layer capacitors.
Diffusion of Arsenic and Phosphorus in Laserprocessed-Polycrystalline-Silicon-Thin-Films
Authors: Baumgart H. , Leamy H. J. , Trimble L. E. , Doherty C. J. , Celler G. K. 
Published: March 2011

ABSTRACTGrain boundary diffusion of arsenic and phosphorus in laser processed polycrystalline Si films has been investigated. Mesa diodes were fabricated in LPCVD Si thin films on SiO2 and subsequently recrystallized by cw Ar ion laser processing to form large grain material. The diffusion length of enhanced As and P diffusion along grain boundaries intersecting the p-n junction has been measured by the EBIC technique. Quantitative experimentation allowed determination of the grain boundary diffusion coefficients of As and P in the temperature range from 900°C to 1250°C.
Furnace Annealing of Ion Implanted Polycrystalline Silicon
Authors: Tandon J.L. , Harrison H.B. , Neoh C.L. , Short K.T. , Williams J.S. 
Published: March 2011

ABSTRACTRutherford backscattering, Van der Pauw and TEM measurements were used to characterise the annealing behaviour of antimony implanted LPCVD polysilicon. High electrical activity without dopant redistribution was obtained for 600°C annealing of 1 × 1015 cm−2 and 3×1015 cm−2 antimony implanted samples. Subsequent annealing at temperatures ≥900° C resulted in considerable grain-boundary-assisted redistribution of antimony within the polycrystalline layers and associated changes in sheet resistance. Our results suggest that the sheet resistance of the films is controlled by dopant segregation at grain boundaries and the fraction of antimony distributed on active sites within individual grains.
Laser Recrystallized Polysilicon on Sio2 For High Performance Resistors
Authors: Shah Rajiv R. , Randy Hollingsworth D. , Lloyd Crosthwait D. 
Published: March 2011

ABSTRACTWe demonstrate, for the first time, a technique for the fabrication of polysilicon resistors with excellent control and temperature characteristics: a standard deviation of 2.5 Ω/□ and temperature variation of -5.6% from 25° to 125°C for 1.96kΩ/□, 4.5 × 1014 cm˗2 boron implanted polysilicon resistors. The technique is based on fabricating resistors in laser recrystallized polysilicon on SiO2. Resistor performance is compared to that of similar resistors fabricated in standard LPCVD polysilicon and in single crystal silicon.