bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructural Studies of Pulsed-Laser Irradiated Graphite Surfaces
Authors: Speck J. S. , Steinbeck J. , Braunstein G. , Dresselhaus M. S. , Venkatesan T. 
Published: March 2011

ABSTRACTThe surface structures of laser-irradiated samples of highly oriented pyrolytic graphite (HOPG) have been investigated using optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM). The samples were irradiated with a 30 ns ruby laser (λ = 6943 !A) pulse with energy fluences ranging from 0.1 to 3.0 J cm−2. Optically, the specimens show a damage region approximately 5 mm in diameter. The surface structure displays three characteristic regions: an outer boundary characterized by submicron carbon spheroids resting on the surface; an inner boundary characterized by both submicron spheroids and 1 to 5 [m ‘torn’ carbon layers which appear to have broken away from the graphite surface after irradiation; a central region characterized by a uniform density of spheroids and a pattern of surface upheavals which trace out a grain pattern similar to that of the pristine substrate. Electron diffraction patterns taken on the irradiated region indicate an ultra-fine grain 2-dimensionally ordered carbon. Qualitative trends in the areal density of different microstructural features are presented. In addition, a simple model explaining the observed features is given. All observations are consistent with the rapid solidification of liquid carbon.
Kinetics, Microstructure And Mechanisms of Ion Beam Induced Epitaxial Crystallization of Semiconductors.
Authors: Elliman R.G. , Williams J.S. , Maher D.M. , Brown W.L. 
Published: March 2011

ABSTRACTIon-beam induced epitaxy is shown to be essentially athermal over the temperature range 200-400°C, and to exhibit no dependence on substrate orientation and little dependence on doping in this regime. On the other hand, the formation and propagation of defects during growth and the interaction of the advancing crystal-amorphous interface with implanted impurities is essentially identical for both thermally induced and ion-beam induced epitaxy. These observations lead to a simple model for ion-beam induced epitaxial crystallization in which epitaxial growth is nucleated by defects generated at, or near, the crystal-amorphous interface by the ion beam. Comparisons of ion-beam induced epitaxy and thermally induced epitaxy suggest that the 2.7 eV activation energy associated with the latter process is dominated by a 2.0 eV nucleation step.
Microstructure of Niobium Films Oriented By Non-Normal Incidence Ion Bombardment During Growth
Authors: Harper J.M.E. , Smith D.A. , Yu L.S. , Cuomo J.J. 
Published: March 2011

ABSTRACTWe demonstrate that non-normal incidence ion bombardment applied during thin film growth has a pronounced alignment effect on crystallographic orientation. Restricted fiber texture is achieved in Nb films deposited at room temperature onto amorphous silica substrates with simultaneous 200 eV Ar+ ion bombardment at 20 degrees from glancing angle. Xray pole figure measurements and transmission electron diffraction show that the alignment direction is a channeling direction for the incident ions between (110) planes. The degree of alignment increases linearly with the fraction resputtered by the ion beam. Recommendations are given for optimizing this ion beam orientation effect.
Trapping of Interstitials During Ion Implantation In Silicon
Authors: Culbertson R.J. , Pennycook S.J. 
Published: March 2011

ABSTRACTThe solid phase epitaxial regrowth of silicon implanted with a group V dopant, such as antimony, results in excellent incorporation of the dopant atoms into silicon lattice sites. However, annealing at higher temperatures or longer times results in transient dopant precipitation with a diffusion coefficient up to five orders of magnitude above that of tracer diffusion and with a reduced activation energy.This precipitation is accompanied by the nucleation of dislocation loops that are interstitial in nature, and the transient ceases as the dislocation loops develop. It is believed that Si interstitials are trapped in a stable defect complex during the implantation process.Although they survive SPE these complexes dissolve at higher temperatures and release a large supply of interstitials which serve to promote dopant migration via an interstitialcy mechanism until they condense to form the observed dislocation loops. By following the Sb implantation with an implantation of B to an equivalent concentration profile the loop formation is efficiently suppressed. For higher B concentrations the Sb precipitation is no longer observed. Results for As implantation are similar to Sb except that As precipitates can not be directly observed. Calculations of the dopant and interstitial concentration depth distributions were also performed.
Temperature And Dose Dependence of An Amorphous Layer Formed By Ion Implantation
Authors: Richmond Eliezer Dovid , Knudson Alvin R. 
Published: March 2011

ABSTRACTA model is formulated to predict the width of an amorphous layer in Si produced by ion implantation. The dependency of the amorphous Si layer width on the ion implantation energy, dose, and temperature is computed.
Formation of Surface Layers of Icosahedral Al(Mn)
Authors: Knapp J. A. , Follstaedt D. M. 
Published: March 2011

ABSTRACTSurface layers of the icosahedral phase of Al(Mn) have been formed from thin, alternating Al/Mn layers deposited on Al or Fe surfaces by rapid electron-beam or laser melting, by ion beam mixing, and by solid-state diffusion. The electron beam and laser treatments are similar to other liquid quenching techniques used previously to form the phase, but have well defined temperature histories which allow us to place limits on the melting point of the icosahedral phase, the time needed for its nucleation from the melt, and its growth velocity. Ion beam mixing is a way of forming the icosahedral phase which is quite different from melt quenching; the phase is formed during ion beam mixing at temperatures of 100–200°C. For mixing at ≤60C an amorphous phase with icosahedral short-range order is formed; this phase can be converted to the icosahedral phase by subsequent annealing. Formation of the icosahedral phase by reacting the as-deposited layers in the solid state is a new technique not previously reported. The results presented here place new restrictions on proposed structural and thermodynamic models for the icosahedral phase.
Metastable Phases Produced In Nickel By High Dose La And 0 Implantation, And Pulsed Laser Melt Quenching
Authors: Sood D.K. , Pogany A.P. , Battaglin G. , Carnera A. , Mea G. Della , Kulkarni V.L. , Mazzoldi P. , Chaumont J. 
Published: March 2011

ABSTRACTNickel single crystals implanted with La, 0 and La + 0, up to about 9 a/o concentrations were irradiated with spatially homogenised ruby laser pulses (16 ns FWHM) up to 3.7 J/cm2 in vacuum (s~ 10−2 Torr). Phase changes, defect structure and solute migration were studied before and after laser melt quenching using RBS/channeling, TEM and SEM techniques.Both La and La + 0 implants produced a buried amorphous layer on top of a polycrystalline layer above the single crystal matrix. 0 implants did not produce an amorphous phase, but a buried layer containing polycrystalline Ni, metastable hcp Ni particles and a dense dislocation network was formed. Pulsed laser melt quenching of these implanted metastable phases lead to a variety of new phases - all crystalline.
Ion Beam Mixing In Binary Amorphous Metallic Alloys
Authors: Hahn Horst , Averback R. S. , Rubia T. Diaz De La , Okamoto P. R. 
Published: March 2011

ABSTRACTIon beam mixing (IM) was measured in homogeneous amorphous metallic alloys of Cu-Er and Ni-Ti as a function of temperature using tracer impurities, i.e., the so called “marker geometry”. In Cu-Er, a strong temperature dependence in IM was observed between 80 K and 373 K, indicating that radiation-enhanced diffusion mechanisms are operative in this metallic glass. Phase separation of the Cu-Er alloy was also observed under irradiation as Er segregated to the vacuum and SiO2 interfaces of the specimen. At low-temperatures, the amount of mixing in amorphous Ni-Ti is similar to that in pure Ni or Ti, but it is much greater in Cu-Er than in either Cu or Er.
Improving the Structural and Electrical Properties of Epitaxial CaF2 on Si By Rapid Thermal Anneaing
Authors: Phillips Julia M. , Manger Mary L. , Pfeiffer Loren , Joy D. C. , Smith T. P. , Augustyniak W. M. , West K. W. 
Published: March 2011

ABSTRACTRapid thermal annealing (RTA) has been shown to be a useful technique for improving the epitaxial quality of CaF2 films grown on Si(100) by molecular beam epitaxy. We have modified the annealing procedure to prevent crack formation, while still maintaining high film quality. Our work also shows RTA to be useful for improving the crystalline quality, chemical stability, and electrical characteristics of CaF2 films grown on Si(111). After RTA, the crystallinity of CaF2 films on Si(111), as measured by electron channeling, is indistinguishable from bulk single crystal CaF2, and the interface state density is reduced by nearly two orders of magnitude from that found in as-grown films.
Enhancing the Grain Size and {110} Texture of Polycrystalline Si Films By Seed Selection Through Ion Channeling: Implant-Dose Dependence
Authors: Kung Kenneth T-Y. , Reif Rafael 
Published: March 2011

ABSTRACTThis work outlines an optimized seed selection through ion channeling (SSIC) process for enhancing the grain size and {110} texture of polycrystalline Si films grown by LPCVD on SiO2. These films, 0.44 μm thick, were self-implanted at normal incidence to various doses (1×1014 - 20×l014 cm-2) and then recrystallized at 600°C. An enhanced average grain diameter resulted after implantation and annealing, ranging from 0.10 to 2.0 μm (vs. the as-deposited 0.080 μm) and increasing with the implant dose. The grain size vs. implant dose behavior may be explained by a previously proposed stochastic model. An enhanced {110} texture was also observed after processing for implant doscs in the range 6×1014 - 14×1014 cm-2. The optimal dose was 11×1014 cm-2, for which the <110> directions were confined to within ±4° (vs. the as-deposited ±20°) of the surface normal. The overall results suggest a strong potential of SSIC in growing large-grain, restricted fibertextured polycrystalline Si thin films on amorphous insulators.
Morphology of Silicon Islands Grown By Selective Epitaxy Over Silicon Dioxide
Authors: Liu S.T. , Newstrom K. , Hibbs-Brenner M. , Stokes R.J. , Hoefflinger B. , Neudeck G. , Zingg R. , Bousse L. , Meindl J.D. 
Published: March 2011

ABSTRACTWe studied the selective epitaxial deposition of silicon in patterned oxide-free regions over silicon dioxide in a RF-heated, commercial, reduced-pressure epitaxial reactor, using SiH2Cl2/HCl/H2 gas system. We found that etching into silicon occurs at the high end of HCl content, and nucleation on the silicon dioxide at the low end of HCl content. The selective epitaxial growth of silicon islands is obtained in between.
Si-MBE SOI
Authors: Lin T.L. , Chen S.C. , Wang K.L. , Iyer S. 
Published: March 2011

ABSTRACT100 μm-wide silicon-on-insulator (SOI) structures have been accomplished by utilizing silicon molecular beam epitaxial (Si-MBE) growth on porous silicon anid subsequent lateral-enhanced oxidation of porous silicon through pattern widows. A silicon beam method was used for insitu cleaning of Si surface at 750°C, and the effectiveness of this method was demonstrated by Auger electron spectroscopy and checked by the etch-pit density of the grown film. A two-step growth process of Si MBE was used to grow epitaxial layers of high quality. An electron mobility of 1300 cm2V-1s-1 was obtained by van der Pauw measurements.
Epitaxial Growth on Simox Wafers
Authors: Lam Hon Wai 
Published: March 2011

ABSTRACTThe top silicon layer in as-implanted SIMOX wafer is usually too thin to support device fabrication. Hence, an epitaxial layer is usually grown on a SIMOX wafer after oxygen ion implantation and anneal. Because this epitaxial layer is typically very thin,less than 500 nm) and because of the material structure of the S1MOX wafer, special care has to.be exercised in order to obtain desirable epitaxial growth. This paper describes the unique problems of epitaxial growth on SIMOX.
The Effects of Annealing Temperature on the Characteristics of Buried Oxide Silicon-On-Insulator
Authors: Mao B.-Y , Chang P.-H. , Lam H.W. , Shen B.W. , Keenan J.A. 
Published: March 2011

ABSTRACTThe effects of post implantation annealing on the properties of buried oxide silicon-on-insulator (SOI) substrates in the temperature range of 1150°C to 1300°C have been studied. Microstructural analyses showed that the crystallinity of the top silicon layer was improved at higher annealing temperature. Lower thermal donor generation at 450°C was observed in SOI annealed at higher temperature. The improvement in microstructure and lower thermal donor generation were correlated to the lower oxygen concentration in the top silicon film.
Crystalline Films on Amorphous Substrates by Zone Melting and Surface-Energy-Driven Grain Growth in Conjunction with Patferning
Authors: Smith Henry I. , Geis M. W. , Thompson C. V. , Chen C. K. 
Published: March 2011

ABSTRACTTwo approaches to preparing oriented crystalline films on amorphous substrates are reviewed briefly: zone-melting recrystallization (ZMR) and surface-energy-driven grain growth (SEDGG). In both approaches patterning can be employed either to establish orientation or to control the location of defects. ZMR has been highly successful for the growth of Si films on oxidized Si substrates, but its applicability is limited by the high temperatures required. SEDGG has been investigated as a potentially universal, low temperature approach. It has been demonstrated in Si, Ge, and Au. Surface gratings favor the growth of grains with a specific in-plane orientation. In order for SEDGG to be of broad practical value, the mobility of semiconductor grain boundaries must be increased substantially. Mobility enhancement has been achieved via doping and ion bombardment.
The Microchemistry of the SiO2/Silicon Interface
Authors: M-Grovenor C.R. 
Published: March 2011

ABSTRACTThis paper deals with the chemical microanalysis of the Si02/si terface by Pulsed Laser Atom Probe (PLAP). The PLAP technique is briefly described, emphasizing its unique advantages in the study of the chemistry of interfaces. A transition oxide layer of stoichiometry SiO has been identified by PLAP analyses of the Si02/S' interface in thermal and anodic oxides. Simple models of the structure of the interface incorporating this SiO layer are presented, and the possible role of this layer during oxidation is discussed.
A Technique for In—Situ Detection of Growth Dislocations
Authors: Peteves S. D. , Sarreal J. A. , Abbaschian G. J. 
Published: March 2011

ABSTRACTA formidable obstacle to develop the optimal conditions for growing dislocation—free crystals has been the lack of a direct technique to monitor the perfection of the solid/liquid (S/L) interface during growth. Recently we have developed a technique which detects, in—situ, the emergence of dislocation(s) at the crystallization front. This novel technique is based on the thermoelectric principles, and utilizesthe dependence of the Seebeck emf generated across the S/L interface upon the interface temperature, crystal orientation, and dopant concentration. The technique was used to directly measure the S/L interface temperature during growth of Ga and In—doped Ga. For the latter, the technique also shows the breakdown (instability) of the faceted interface, which leads to the entrapment of the In—rich bands. The applicability of the technique to monitor defect formation during crystal growth processes such as thin film zone, Czochralski, or liquid phase epitaxy will be discussed.
Electrical Characterization of Beam—Recrystallized Soi Structures Using a Depletion Mode Transistor
Authors: Vu D.P. , Chantre A. , Ronzani D. , Pfister J.C. 
Published: March 2011

ABSTRACTWe show that a depletion mode transistor is a very versatile tool for the electrical characterization of SOI structures. We apply it to Si thin films recrystallized by a zone—melting technique in which grainboundaries are localized. Apart from the transportparameters, one can get from drain—source current the information usually determined from a MOS capacitor. Owing to the existence in such a transistor of two MOS structures, we are able to characterize both Si-SiO2 interfaces as well as the “bulk” of the Si film.
Process and Device Considerations for Small Grain Polysilicon Transistors
Authors: Shichijo H. , Malhi S.D.S. , Sundaresan R. , Banerjee S.K. , Lam H.W. 
Published: March 2011

ABSTRACTPolysilicon transistors offer the first entry into 3-dimensional ICs. This paper reviews some process and device considerations in using these devices in VLSI environments. The process issues include the choice of polysilicon grain size, layer thickness, doping, and methods of grain boundary passivation. The device considerations are closely related to the effects of grain boundaries in modifying the device characteristics. Three specific application examples are reviewed. It is concluded that polysilicon transistors offer new possibilities to enhance the performance of bulk technologies without resorting to any recrystallization techniques.
Two-Beam Laser Recrystallization of Silicon on an Insulating Substrate
Authors: Dasgupta Samhita , Jackson Howard E. , Boyd Joseph T. 
Published: March 2011

ABSTRACTLaser recrystallization of silicon on an insulating substrate has been carried out by irradiating polysilicon with both an Ar+ laser operating on all lines in the visible and a CO2 laser operating at 10.6 microns. These experiments were carried out over a variety of laser power densities and substrate temperatures. The use of the two lasers allowed for independent spatial control of temperature in both the polysilicon and the SiO2 layers and helped to reduce the strain at the polysilicon - SiO2 interface. We report the successful recrystallization of polysilicon films without substrate heating for two different silicon-on-insulator structures.
Sputter Deposited, Electrically Conductive, Oxidation Resistant Coatings
Authors: Rutledge Sharon K. 
Published: March 2011

ABSTRACTSignificant polymer weight loss has been observed due to environmental ashing by atomic oxygen at low earth orbital (LEO) altitudes. Static charging during deployment and charging caused by the space plasma in LEO polar orbits may cause electromagnetic interference (EMI) problems on insulating polymer materials that are integral to such applications as high voltage solar arrays. Simultaneous ion beam sputter deposited coatings of indium-tin-oxide (ITO) with polytetrafluoroethylene (PTFE), carbon, air, or methane were investigated as potential solutions to these problems. The purpose of this research was to improve the flexibility of ITO coatings with these additives and to study the effect the addition of these materials had not only on the flexibility of ITO sputter deposited thin films but also on the conductivity and optical properties.
Can Amortization Bs Induced by Ion Mixing in Ag-Cu and Ag-Ni Systems?
Authors: Liu B. X. , Huang L. J. , Li J. , Ma S. 
Published: March 2011

ABSTRACTThe extended Structural Difference Rule for amorphous phase formation states that an amorphous phase can be obtained by ion mixing with an alloy with a composition lying in a two-phase region in the equilibrium phase diagram. This criterion has to respond to the challenge that no amorphous alloy has been formed in some early studied systems exhibiting a two-phase region character, e.g. Ag-Cu(typical eutec-tic),Ag-Ni(almost entirely immiscible),etc‥We performed ion mixing experiments for several systems at liquid nitrogen temperature using Xe ions with low current density. Amorphization was indeed observed in both Ag-Cu and Ag-Ni samples, as two halos were seen by TEM SAD immediately after adequate doses ion mixing. These not only support our two-pnase region rule, but also show the possibility of amorphization in a system(Ag-Ni) that has large positive heat of formation.
Computer Simulation of Marker Evolution Upon Ion Irradiation
Authors: Cui Fu-Zhai , Li Heng-De , Liu Bai-Xin 
Published: March 2011

ABSTRACTIn ion beam mixing, the subject on the marker evolution of Si/Pt/Si target during 300 keV Xe ion irradiation has been an interesting topic of recent years. A cottputer simulation for this system by using the Monte Carlo code TCIS-4 is reported here. Dynamic target model was employed. Some radiation-enhanced diffusion and relaxation of the displacement cascades were also considered. Results of this simulation study reveal the evolution of Pt marker profile with fluences during bombardment. The shifts of Pt marker and the dispersions evaluated from the profiles agree fairly well with experimental date, demonstrating a reslistic model of the target being irradiated is important.
Epitaxial Growth of Transition Metal Silicides on Silicon
Authors: Chen L. J. , Cheng H. C. , Lin W. T. 
Published: March 2011

ABSTRACTRecent progresses in the epitaxial growth of refractory metal suicides, FeSi2 and manganese suicides on silicon are reviewed.The formation and structures of epitaxial suicides are described. Factors affecting the suicide epitaxy are examined. The lattice match criteria for the growth of epitaxial suicides are assessed. The effects of anharmonicity in the interatomic force of overlayer on the heteroepitaxial growth and pseudomorphism are discussed. The properties and possible applications of epitaxial suicides are summarized. Prospects for the study of epitaxial suicides are addressed.
Initial Nucleation and the Effects on Epitaxial Silicide Formation
Authors: Nemanich R. J. , Doland C. M. , Fulks R. T. , Ponce F. A. 
Published: March 2011

ABSTRACTThe initial nucleation processes for reactions of Pd and Ti on Si are studied by Raman scattering, and Auger electron spectroscopy. The epitaxial nature of the structures is verified by high resolution TEM. A model of the interface reaction is presented which describes the initial interdiffusion and subsequent nucleation. The aspects of nucleation in a thin film reaction are compared to nucleation processes in vacuum deposition. For Pd/Si a critical depostion thickness is observed which is related to a critical nuclei size. For Ti/Si higher annealing temperatures are required to bring about conditions for nucleation of the suicide.
MBE Growth of Epitaxial Calcium Fluoride on Silicon
Authors: Schowalter L. J. , Fathauer R. W. 
Published: March 2011

ABSTRACTThe growth of an epitaxial insulator such as CaF2. on Si substrates and ita subsequent overgrowth with epitaxial sen iconduct ors have a number of important applications in the electronics industry. In addition, it presents a unique opportunity to study an insulator/semiconductor interface under controlled conditions. We have studied the growth of epitaxial CaF. on Si substrates and their subsequent overgrowth with Si or Ge under various conditions. While epitaxial growth of CaF2, (which has an fee lattice structure as does Si) can be obtained on (100), (110) and (111) oriented Si substrates, the best quality crystal growth and surface morphology is obtained on (111) substrates as the CaF. (111) surface has the lowest free energy. Atomic steps on the original Si substrate surface are shown to have a detrimental effect on the epitaxial growth of CaF2. I-V measurements on the epitaxial (111) films show that the intrinsic breakdown field strength exceeds 2 MV/cm, however, high-field induced ionization can cause thermal breakdown at lower voltages. C-V measurements typically show ∼1012 states/cm in the Si band gap as grown. However, it is possible to reduce this number to less than 10 by annealing procedures after growth.