bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anneal Behavior of Zn Implanted InP : Furnace and Rapid Thermal Anneals
Authors: Djamei M. , Rao E.V.K. , Krauz P. 
Published: March 2011

ABSTRACTIt is shown here that high-dose Zn implants in semi-insulating InP substrates, after conventional furnace anneals lead to the following anomalies : step-like atomic Zn and carrier distributions and the presence of electrically inactive Zn at all depths of the profiles.Zn anneal behavior is compared using conventional furnace anneals, and two different types of short-time anneals ; rapid furnace anneals(RFA)at ∼750°C with a rise-time of ∼ 50 s, and halogen lamp rapid thermal anneals (RTA)also at ∼ 750°C with a rise-time of ∼ 4 s. We have established that the Zn anomalous diffusion is an instantaneous phexomenon occuring during annealing transients. Also, we have further shown that RTA would help to smooth carrier profiles by removing the step in carrier (but not in atomic Zn) distribution.The properties of differently Zn co-implanted layers (Zn plus P, Zn plus In and Zn plus As) after RTA, and of P or In implanted Zn doped InP substrates after different anneals,have been studied. We have shown that the presence of electrically inactive Zn in the depth of the layers is a consequence of interaction between Zn atoms and defects. A simple model based on the density of damage deposited in the layer during implant, has been proposed and discussed.
Tungsten Silicide Zinc as a High Temperature Zinc Diffusion Source
Authors: Plumton D.L. 
Published: March 2011

ABSTRACTA process for Zn diffusion into GaAs during rapid thermal processing has been developed using Zn doped tungsten silicide as the diffusion source. The WSi:Zn is a sputter deposited, solid source layer that undergoes capless annealing in a quartz-halogen lamp system. For a given time and temperature the diffusion of Zn into GaAs is controlled by both the Zn concentration and the W/Si ratio in the film. Tungsten-rich films are Zn concentration “independent” while Si-rich films are Zn concentration “dependent.” Changing the film composition allows shallow Zn diffusions at either a low or a high temperature. Deep Zn diffusions are possible through higher temperatures or longer anneal times for any given WSi:Zn composition.
Drift of Arsenic in SiO2 in a Lamp Furnace With a Built-In Temperature Gradient
Authors: Celler G. K. , Trimble L. E. , West K. W. , Pfeiffer L. , Sheng T. T. 
Published: March 2011

ABSTRACTWe have found that arsenic implanted into SiO2 segregates at high temperatures in an oxygen-free ambient into spherical, As-rich inclusions of 50 to 500A in diameter. The phase separation prevents diffusion of arsenic, even at temperatures as high as 1400 °C. However, the As-rich inclusions or droplets can be easily moved in a temperature gradient. They migrate towards the heat source at a rate of 2300A /hour in a gradient of 0.14 °C/μm, at 1405 °C, permitting their efficient removal from the oxide and into silicon. We propose a model to explain the dependence of droplet velocity on their size.
Applications of Pulsed Co2 Laser Processing of Silicon
Authors: James B. 
Published: March 2011

ABSTRACTThe absorption of CO2 laser radiation in doped silicon is dominated by free-carrier transitions, which is an extrinsic absorption property. For applications where one would like to preferentially deposit the pulse energy in heavilydoped layers, the CO2 laser is found to be preferable to other laser systems that oscillate at a photon energyexceeding the bandgap.The advantages of laser processing with below-bandgap radiation are illustrated by three different applications that areeither impossible or much more difficult to achieve with a visible or ultraviolet laser: (1) the melting of buried layerswithout melting the material that encapsulates the molten layer, (2) the melting of shallow layers at the surface, and(3)the annealing of lattice imperfections caused by high-temperature diffusion of phosphorus dopants into small diffusion wells.
Characterization of Shallow Junctions Fabricated by Gas Immersion Laser Doping (Gild)
Authors: Carey P.G. , Turner J. E. , Nauka K. , Reid G. A. , Sigmon T. W. 
Published: March 2011

ABSTRACTThe viability of Gas Immersion Laser Doping (GILD) for VLSI processing of ultra shallow junctions is assessed using chemical, electrical and structural characterization of boron doped diodes. Diodes with good ideality factors (1.1) overarange of junction depths (50nm Xj 200 nm) have been fabricated by GILD. This process uses a pulsed XeCI excimer laserincident on a silicon surface saturated with B2H6.Dopant profiles as a function of laser energy and number of pulses aredetermined using Secondary Ion Mass Spectrometry(SIMS). For low energy or a large number of pulses, comparison with computer modelling suggests the junction is determined by melt depth. For higher laser energy and few pulses, liquid phase diffusion limits the depth of dopant incorporation.Leakage current measurements as a function of diode perimeter to area (P/A) ratio and Deep Level Transient Spectroscopy (DLTS) suggest that leakage occurs along the diode perimeter, and is dueto point defects generated from thermal stresses during melt regrowth. Diodes show good I-V characteristics after GILD alone, yet subsequent rapid thermal annealingisfound to further reduce leakage currents, probably due to relief of thermal stresses. Sheet carrier densities from Halleffect measurements show that 5 - 10% of the boron is activated, with doping levels exceeding 1020 cm−3 in some samples. Transmission Electron Microscopy (TEM) demonstrates that reasonable crystalline quality is maintained for moderate GILD conditions with a defect density at the surface of approximately 108 cm−2 .For higher laser energy with boron incorporation exceeding solid solubility, TEM shows stacking faults along <110>directions. Electron diffraction on highly doped samples shows extra spots indicating a high degree of strain in the doped layer.
High-Quality SOI by Oxygen Implantation into Silicon
Authors: Ommen A. H. van , Ligthart H. J. , Politiek J. , Viegers M. P. A. 
Published: March 2011

ABSTRACTHigh quality Silicon-On-Insulator, with a dislocation density lower than 105cm−2, has been formed by high temperature annealing of high-dose oxygen implanted silicon. In the as-implanted state, oxygen was found to form precipitates in the top silicon film. In the upper region these precipitates were found to order into a superlattice of simple cubic symmetry. Near the interface with the buried oxide film the precipitates are larger and no ordering occurs in that region. Contrary to implants without precipitate ordering where dislocations are observed across the entire layer thickness of the top silicon film, dislocations are now only found near the buried oxide. The precipitate ordering appears to prevent the dislocations to climb to the surface. High temperature annealing results in precipitate growth in this region whereas they dissolve elsewhere. These growing precipitates pin the dislocations and elimination of precipitates and dislocations occurs simultaneously, resulting in good quality SOI material.
Mechanisms of Formation of Thin Buried Oxide Layers by Ion Implantation
Authors: White Alice E. , Short K. T. , Pfeiffer L. N. , West K. W. 
Published: March 2011

ABSTRACTWe have studied buried oxide formation as a function of implantation and annealing conditions. The layers appear to form via a nucleation and growth process, so the quality of the oxide and the perfection of the overlying crystalline Si layer depend more strongly on the substrate temperature during implantation than on the annealing temperature. Since it is easier to observe the layer formation process in a thin (<1000Å) layer, we concentrated on sub-stoichiometric doses and chose substrate temperatures below 400°C to stay in a homogeneous nucleation regime. Then we varied the annealing temperature from 1150°C to 1407°C. Modeling the coalescence of the oxide layer as a thermally-activated process yields activation energies of approximately 6 eV, suggesting that crystalline damage removal may be the bottleneck for this substrate temperature regime.
Comparison of the Electrical Properties of Thermal and Ion Beam Oxides
Authors: Dumin David J. , Fossum E. R. , Todorov S. S. 
Published: March 2011

ABSTRACTA comparison of the current-voltage (I-V) and the capacitance-voltage (C-V) characteristics of thermal and low temperature ion beam grown films of silicon oxide was made. The oxides were in the thickness range between 5 nm and 10 nm. The ion beam oxides were grown at room temperature. The bulk resistivities of the thermal oxides were about 1017 ohm cm and were about 5 orders of magnitude lower for the ion beam oxides. The interface charge densities at the Si-SiO2 interface were about an order of magnitude higher in the case of the ion beam oxides. The oxide properties were also measured after current stressing at constant voltages. The thermal oxides showed an increase in the interface trap density at the Si-SiO2 interface after stressing with a distinct trap appearing above mid-gap. The ion beam oxides showed very little increase in the interface trap density after stressing. The higher conductivity of the ion beam oxides may have lead to discharging of the interface traps generated during stressing.
Semiconductor Superlattices: Order and Disorder
Authors: Hull R. , Turner J. E. , Fischer-Colbrie A. , Whitea Alice E. , Short K. T. , Pearton S. J. , Tu C. W. 
Published: March 2011

ABSTRACTWe review and discuss the main structural phenomena inherent in epitaxial multilayer semiconductor growth: lattice mismatch, misfit dislocation generation, two-dimensional vs. threedimensional growth, interface abruptness and planarity and the local atomic structure of semiconductor alloys. The prevalence of metastable structures, often a function of crystal growth temperature, is discussed. We also investigate the effect of Si ion implantation and subsequent rapid thermal annealing of AlGaAs/GaAs and InGaAs/GaAs multilayer structures, with reference to strain relaxation, layer planarity and enhanced Al, In and Si diffusion.
Ion Beam Mixing of Au-Ti
Authors: Fleischer E. L. , Mayer J. W. , Hirvonen J-P. 
Published: March 2011

ABSTRACTMulti-layered films of Ti-Au of linearly varying composition were produced by ion irradiation using 600 KeV Ar++ ions. Rutherford Backscattering Spectrometry showed that mixing was complete. The microstructure observed by transmission electron microscopy consisted of a combination of crystalline and amorphous phases at the Ti-rich end and of a crystalline fcc Au solid solution at the Au-rich end. Corrosion testing in a simple immersion cell revealed remarkable corrosion resistance of the ion beam mixed sample compared to that of pure titanium or as-deposited Ti-Au samples (from 100%Au to 60%Ti-40%Au). Wear and friction testing was performed using a reciprocal sliding apparatus with a polytetrafluoroethylene (PTFE) pin. A composition of 60%Ti-40%Au was chosen as optimal for improved corrosion resistance without appreciable degradation in wear and friction properties.
Identification of Cluster Beam Constituents and Qualitative Descripton of Cluster Emission from Liquid Gold Ion Source
Authors: Bahasadri A. , Pourrezaei K. , François M. , Nayak D. 
Published: March 2011

ABSTRACTThe distribution of charged gold clusters and micro droplets emitted from liquid gold ion source as a function of charge to mass ratio has been investigated using three complementary techniques: transverse magnetic deflection, quadrupole mass spectrometry, and single particle detection scheme. The measurements have been made as a function of total beam current and angle of emission. The above three methods have some overlap range that was used for comparison and verification of data gathered by each technique. The magnetic deflection results indicate that for the source structure used in this study, clusters are present along the axis of the beam, over the entire current range under investigation. However, their relative abundance is significantly increased as total current is increased. The quadrupole data exhibits a broad peak which is centered around 104 Coul/Kg corresponding to a cluster of ≈ 1000 atoms charged to ≈20+. The position of the peak moves slightly toward lower mass (higher Q/m ratio) as the total beam current is increased. The biggest cluster detected so far using single particle detector has a charge to mass ratio of 17 Coulomb/Kg corresponding to a droplet of 108 Au atoms having a radius of ≈ 740Å atoms charged to ≈ 9000+. Several experimental observations point to the fact that cluster dominated emission mode might be qualitatively different from ion emission mode. Based on experimental observations a qualitative model for cluster emission is proposed.
Enhanced Rate of SIO2 Growth in Ge-Implanted SI
Authors: Fathy D. , White C. W. , Holland O. W. 
Published: March 2011

ABSTRACTThe implantation of Ge in Si has been found to considerably increase the steam oxidation rate of Si under certain conditions. This effect has been studied for a range of implanted ion energies and doses. During steam oxidation, implanted Ge is rejected from the growing oxide and forms a thin layer between SiO2 and Si. Segregated Ge is epitaxial with the underlying Si, and leads to enhanced oxidation of the underlying Si. Evidence suggests that the Ge alters the interfacial kinetics associated with oxide formation.
Solid-Phase Epitaxy of Ti-Implanted LiNbO3
Authors: Poker D. B. 
Published: March 2011

ABSTRACTThe implantation of Ti into LiNbO3 has been studied as a means of altering the optical index of refraction to produce optical waveguides. Implanting 2 × 1017 atoms/cm2 of 360-keV Ti at liquid nitrogen temperature produces a highly damaged region extending to a depth of about 4000 Å. Solid-phase epitaxial regrowth of the LiNbO3 can be achieved by annealing in a water-saturated oxygen atmosphere at 400°C, though complete removal of the residual damage usually requires temperatures in excess of 800°C. The solid-phase epitaxial regrowth rate exhibits an activation energy of 2 eV at doses below 3 × 1016 Ti/cm2, but both the regrowth rate and activation energy decrease at higher doses. At doses above 1 × 1017 Ti/cm2, the solid-phase epitaxial regrowth occurs only at temperatures above 800°C.
Indium Ion Doping During Si Molecular Beam Epitaxy
Authors: Hirashita N. , Noel J.-P. , Rockett A. , Markert L. , Greene J.E. , flasan M.A. , Knall J. , Ni W.-X. , Sundgren J.-E. 
Published: March 2011

ABSTRACTA single-grid UHV-compatible ion source was used to provide partially-ionized accelerated In+ dopant beams during Si growth by molecular beam epitaxy (MBE). Indium incorporation probabilities in 800 °C MBE Si(100). as measured by secondary ion mass spectrometry, ranged from < 10−5 (the detection limit) for thermal In to values of 0.02–0.7 for In+ acceleration energies EIn, between 50 and 400 eV. Temperature-dependent Hall-effect and resistivity measurements were carried out on Si films grown at 800 °C with EIn = 200 eV. Indium was incorporated substitutionally in electrically active sites over the entire concentration range examined. 1016— 1019 cm−3, with an acceptor level ionization energy of 165 meV. The 111 meV level associated with In-C complexes and the 18 meV “supershallow” level reported for In ion-implanted Si were not observed. Roomtemperature hole mobilities μ were higher than both annealed In-ion-implanted Si and Irvin's values for bulk Si. Phonon scattering was found to dominate at temperatures between 100 and 330 K and μ varied as T−22.
Tribological Properties of Ion Implanted Amorphous Fe50Ti50 Films
Authors: Hirvonen G.-P. , Nastasi M. , Mayer J. W. 
Published: March 2011

ABSTRACTA surface layer of Fe50Ti50 on AISI 304 stainless steel was produced by ion beam mixing a Fe-Ti multilayer structure. Subsequently, the layer was implanted with C, N, or C+N ions. The dry sliding properties of these surfaces were tested using a ceramic pin as a rider in pin-on-disc measurements. Implantations produced significant improvements in the surface friction and wear properties. Samples implanted with C or C+N showed good tribological properties even under conditions where the Herzian peak pressure exceeded the yield strength of the substrate. As a result of different treatments the appearance of the wear tracks examined with a scanning electron microscope was also changed.
Broad Beam Ultrahigh Current Density Ion Implantation
Authors: Sampath W. S. , Wilbur P. J. 
Published: March 2011

ABSTRACTIn order to achieve low cost rapid surface modification of mechanical components a broad beam (10 cm. dia.), ultrahigh current density (up to 1500 μA/cm2) ion implanter has been developed at Colorado State University. The characteristics of ultrahigh current density ion implantation are compared to those of conventional ion implantation and the relative advantages of the ultrahigh current density implantation are identified. The temperature rise that typical implanted surfaces experience during implantation at various current densities are measured and compared with numerical heat transfer calculations. It is shown that even though the temperature rise can be high at ultrahigh current density implantation conditions, the times at temperature are sufficiently short (typically, 11 sec.) so that no significant tempering, annealing or other diffusion based transformations in the bulk material (i.e. beneath the implanted layer) are induced. The microstructure and hardness beneath the implanted layer are compared before and after ultrahigh current density ion implantation. The results on 1018 martensitic steel, 440C martensitic steel, 52100 martensitic steel, 304 stainless steel, Ti-6A1–4V and 2024-T3 aluminum are presented. The substantial advantage of much deeper (fourfold) ion penetration observed with ultrahigh current density implantation is identified. It is suggested that this increased depth of penetration is due to the phenomenon of radiation enhanced diffusion.
Modification of Stainless Steel Surfaces by Ion Beams for Improved Corrosion Resistance
Authors: Bhattacharya R. S. , Raffoul C. N. , Rai A. K. , Pronko P. P. 
Published: March 2011

ABSTRACTAn investigation of the ion beam mixing of Mo and Ta layers with 304 stainless steel and the potentiodynamic polarization behavior of the modified surfaces are described.Alternating thin layers (<100Å) of stainless steel (304) and either Mo or Ta were deposited by electron beam evaporation. Ion mixing was performed with 2 MeV Ni+ at a fluence of 5 × 1016cm−2. Examination of the mixed surfaces with TEN revealed characteristics of the amorphous phase and in some cases being embedded with crystalline regions for both Mo and Ta mixed stainless steel surfaces. The amorphous surfaces were tested for their corrosion behavior in 1M H2SO4 and O.1M NaCl solutions by the potentiodynamic polarization method. Significantly improved corrosion behavior were obtained for modified surfaces compared to unmodified stainless steel.
Preparation of Thin Films of some Rem Oxides and study of Their Structure, Optical, and electrical properties
Authors: Gvelesiani G. G. , Katsitadze M. A. , Andreeva A. F. 
Published: March 2011

ABSTRACTBy ion bombardment of yttrium and europium hot-pressed oxide targets, their amorphous polycrystalline and monocrystalline films have been obtained on the monocrystalline substrates of (111) molybdenum and (1012). (0001) sapphire. The growth direction of the monocrystalline films with respect to the material and orientation of the substrates corresponds to (011). (211) planes for Y2O3 and (011) Eu2O3.It is determined that the structural imperfection of the grown films does not influence either the square root dependence of the absorption coefficient on decreasing photon energy, the value of their specific electric resistance, or the character of its temperature dependence. The values of the forbidden zone width as well as the energy of the investigated oxide conductivity activation are calculated on the basis of experimental results.It is shown that the light absorption in the Y2O3, Eu2O3 films is mediated by the direct allowed transitions of electrons from the valence band to the conduction band whose extrema are at the same point in k-space. The conductivity of the metal-dielectric-metal structure based on a monocrystalline film of yttrium oxide is mediated by the Frenkel-Poole mechanism.
Defects Annealing of Si+ Implanted GaAs at RT and 100°C
Authors: Bai G. , Jamieson D. N. , Nicolet M-A. , Vreeland T. 
Published: March 2011

ABSTRACTAnnealing behavior of point defects near room temperature is studied by measuring the strain relaxation of Si+ implanted GaAs. Polished semi-insulating GaAs wafers were implanted with 300keV Si+ at liquid nitrogen ( LN2 ) and room temperature (RT ). The strain profile was obtained by the X-ray Double Crystal Diffraction ( DCD) technique and kinematical fitting. The maximum strain of the samples stored at RT and elevated temperature 100°C in air, decreases with time, which indicates the reduction of point defects. Relaxation is exponential in time. At least two time constants of 0.24hrs and 24hrs are needed to fit the data, suggesting that two different processes are responsible for annealing defects. Time constants are obtained for different doses at RT and LN2 implantation temperature, and found to be insensitive to both these quantities. The activation energy for defect migration is estimated using simple diffusion model.
Ion Implantation and Annealing of SrTiO3 and CaTiO3
Authors: White C. W. , Boatner L. A. , Rankin J. , Aziz M. J. 
Published: March 2011

ABSTRACTIon implantation damage and thermal annealing results are presented for single crystals of SrTiO3 and CaTiO3. The near-surface region of both of these materials can be made amorphous by low doses (∼1015/cm2 ) of heavy ions (Pb at 540 keV). During annealing, the amorphous implanted region crystallizes epitaxially on the underlying single-crystal substrate. The kinetics of this solid-phase epitaxial recrystallization process have been measured by employing ion channeling techniques.
Mesotaxy: Single-Crystal Growth of Buried Silicide Layers
Authors: White Alice E. , Short K. T. , Dynes R. C. , Garno J. P. , Gibson J. M. 
Published: March 2011

ABSTRACTRecent progress in the growth of thin epitaxial silicides on silicon has resulted in films of very high quality with especially smooth interfaces. Using a completely different technique, high dose implantation followed by annealing, we have succeeded in creating buried single-crystal layers of CoSi2, NiSi2, and CrSi2 in crystalline silicon. The CoSi2 and NiSi2 layers grow in both the (100) and (111) orientations--those in (111) have better crystallinity, but those in (100) are of higher electrical quality. The CrSi2, on the other hand, only grows in the (111) orientation where its hexagonal structure has an almost perfect lattice match to silicon. We call this new internal growth process “mesotaxy” by analogy with epitaxy which refers to single-crystal growth on surfaces.
X-Ray Diffraction Study of Phase Formation and Growth in Nitrogen Implanted Iron: Temperature Effects
Authors: Arnott R. J. , Burns F. C. , Carreiro L. G. , Chiphan D. R. , Croft W. J. , Johnson E. A. , Marzik J. V. , Sagalyn P. L. 
Published: March 2011

ABSTRACTWe report preliminary results from an ongoing study of iron nitride grains formed in high purity iron under nitrogen ion bombardment. Under various implantation conditions, different iron nitride phases grow large enough to produce sharp x-ray diffraction lines. We have used these lines to examine the influence of target temperature during implantation. Between 200°C and 400°C increasing target temperature, which enhances dopant mobility, reduces the retained dose of nitrogen and restricts the formation of nitride phases. Over this temperature range, however, increasing vacancy mobility favors the growth of nitride grains and x-ray line breadth data suggests an optimum temperature for growth of Fe4N grains.