bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amorphisation Tendency of Intermetallic Compounds Under Electron Irradiation
Authors: Luzzi D. E. , Meshii M. 
Published: March 2011

AbstractThe chemical disordering model for the electron irradiation induced crystalline to amorphous (C-A) transition was previously developed using in-situ experiments in the intermetallic compounds of the Cu-Ti binary alloy system. In the context of this model, a rule was developed which predicts the amorphisation tendency of these and other binary intertransition metal compounds with an accuracy of 92% in the 38 compounds studied to date. Two aspects of this rule, the composition of the compound and the crystal structure are examined through a first approximation computer comparison of ordered, partially ordered, and disordered crystal structures. It is found that in bcc based compounds and in complex crystal structure compounds, the ability of the chemical disordering to raise the energy of the crystal is severely inhibited at compound compositions away from 50:50. During the disordering process, the greatest increase of the crystal energy occurs during the early stages of chemical disordering. These results mesh well with the concept of an amorphous transition driven by the energy increase due to chemical disordering.
Formation of Submicron Metastable Phase Structures in Alloys with Focused Electron or Proton Beams
Authors: Lam N. Q. , Okamoto P. R. , Leaf G. K. 
Published: March 2011

AbstractRecent theoretical and experimental studies of radiation-induced segregation in alloys under irradiation with focused charged-particle beams have shown that point-defect currents generated by axial and radial displacement-rate gradients can cause significant redistribution of the alloying elements within the irradiated zone. In the case of irradiation of thin films with highly-focused electron beams, two important features have been established experimentally: (i) the diameter of the local region in which the alloy composition and phase are modified is practically equal to the beam diameter, and (ii) the time required to produce a given change in the alloy composition in the center of the irradiated zone decreases rapidly with beam diameter. Our theoretical modeling indicates that these features will also be observed in semi-infinite alloys bombarded with focused proton beams. However, in this case, the spatially-nonuniform defect production in both the axial and radial directions renders the compositional redistribution more complex. The present work shows that the ability to locally modify the alloy composition by focused electron or proton beams may offer a new method for producing local regions of controlled composition and microstructure on a submicron scale. The results of our model calculations and experimental studies will be presented to demonstrate the feasibility of this novel technique.
Elimination of Subboundaries in 0.5-µm-Thick Si-on-Insulator Films Produced by ZMR
Authors: Geis M. W. , Chen C. K. , Smith Henry I. 
Published: March 2011

AbstractWhen Si-on-insulator films 0.3 to 0.5 µm thick are recrystallized by zone melting under the usual conditions, the defect trails within grains are subboundaries. We report that the use of an entrainment pattern, consisting of a grating of carbonized photoresist on top of the SiO2 encapsulating layer, can lead to the replacement of subboundaries by defect trails that are spaced dislocation clusters or discrete threading dislocations. Such defects are expected to be less detrimental to submicrometer MOSFET circuits than subboundaries.
Limited Reaction Processing
Authors: Gibbons James F. , Gronet C. M. , Sturm J. C. , King C. , Williams K. , Wilson S. , Reynolds S. , Vook D. , Scott M. , Hull R. , Nauka C. , Turner J. , Laderman S. , Reid G. 
Published: March 2011

AbstractLimited reaction processing (LRP), a new technique which provides precise control of thermally driven surface reactions, was used to grow multilayer structures composed of semiconductors and insulators. Results are presented for group IV-based materials including epitaxial Si, SiGe alloys, SiO2, and polysilicon. III–V materials such as GaAs, AlGaAs, and InGaAs have also been successfully grown. A number of diagnostic techniques were used to define the advantages and capabilities of LRP, including TEM, SIMS and AES. In addition, some preliminary device results are presented.
Rapid Thermal Oxidation of Polysilicon and Silicon
Authors: Nulman Jaim 
Published: March 2011

AbstractGrowth kinetics of silicon dioxide films grown by rapid thermal processing on polysilicon and single crystal silicon films is described. Oxides were grown in pure oxygen and oxygen with up to 4% HCI. For process time in the 1 to 120 s, oxide films thicknesses in the 2 to 36 nm are obtained with a uniformity of ±2% across 100 mm wafers. These oxides show an interface density of states of 5×109 eV−1cm−2 after a 30 s post-oxidation anneal in nitrogen ambient at 1050 C.
Effects of Indium Preamorphization on Boron Implanted Silicon Annealed by RTA
Authors: Ganin E. , Scilla G. , Sedgwick T. O. , Sai-Halasz G. A. 
Published: March 2011

AbstractPreamorphization by indium of boron implanted silicon layers has been studied as a means of reducing defects in the annealed and activated shallow junctions. The In preamorphized samples after RTP annealing at 950 to 1150°C show an absence of spanning dislocations. A 5 sec. anneal at 1100 °C results in the complete annihilation of residual dislocation loops at the original crystalline/amorphous (c/a) interface. The minimum dose to preamorphize Si with 200keV In was 5×1013/cm2. During annealing the In was found to localize at two peaks, one at the original c/a interface and the other closer to the surface, where In precipitation was observed.
Recrystallization of Implanted LPCVD Amorphous Si Films Using Rapid Thermal Annealing
Authors: Kwor R. , Tang S. M. , Alvi N. S. 
Published: March 2011

AbstractThe effect of rapid thermal annealing on the crystallization of arsenic and boron implanted amorphous silicon films is studied. Amorphous Si films of 4000 Å were deposited using LPCVD and implanted with arsenic or boron to doses of 5 × 1013, 5 × 1014, and 5 × 1015 cm−2. These films were then annealed using an Eaton Nova-400 RTA system (with temperature ranging from 900 to 1200 °C and dwell time ranging from 1 to 30 sec). The annealed films were studied using transmission electron microscopy, Hall effect measurement and temperature coefficient of resistance measurement. The optimal annealing conditions for the films were found.
Chemically-Enhanced GaAs Maskless Etching Using a Novel Focused Ion Beam Etching System with a Chlorine Molecular and Radical Beam
Authors: Takado N. , Asakawa K. , Arimoto H. , Morita T. , Sugata S. , Miyauchi E. , Hashimoto H. 
Published: March 2011

AbstractChlorine-enhanced GaAs maskless etching using a novel focused-ion-beametching (FIBE) system has been examined for establishing high-rate and smooth FIBE. The system is composed of an air-locked ultrahigh-vacuum chamber, a 30 KeV Ga+ FIB column and two kinds of chlorine-irradiation nozzles. A fine nozzle enabled us to irradiate a high-density Cl2 flux on a desired, small area of the sample while retaining a sufficiently low surrounding-gas pressure for stable Ga+ FIB emission. Highly chemically-enhanced sputtering yields (up to 50 GaAs molecules per incident ion) were obtained. At the maximum yield, line-scanned deep-groove (6.5 um) etching with a smooth surface, capable of fabricating a laser-cavity optical mirror, was demonstrated. The chemical-enhancement effect showed high FIB-scanning-time dependence. This effect was also observed by irradiating with a plasma-dissociated Cl radicals using a novel radical beam gun. An analytical model, based on the Ga+-ion bombardment on the chlorine-adsorbed substrate surface, suggested that the maximum chemical enhancement is obtained when the Ga+-FIB scanning time is adjusted to the chlorine-coverage time, given by the Cl2-molecule or Cl-radical flux density.
Surface Photochemically Activated Chemical Vapor Deposition of Patterned Aluminum Thin Films
Authors: Higashi G. S. , Blonder G. E. , Fleming C. G. 
Published: March 2011

AbstractKrF excimer laser (248 nm) images of mask patterns have been Iused to photochemically activate tihe surface catalytic decomposition of triisobutylaluminum (TIBA). The activation step is shown to involve the photolysis of organoaluminum surface adlayers leading to the formation of reactive Al sites. These sites serve to selectively nucleate the thermal decomposition of TIBA which results in the growth of high quality Al filns (resistivities ∼5 μΩ-cm). The growth on the chemically inert surfaces of SiO2 and Al2O3 is extremely selective and results in patterns with resolutions ∼2 μm. To evaluate the utility of this process for real circuit applications, the laser activated deposition technique has been used in conjunction with standard photolithographic processing to fabricate metal-oxide field effect transistors and Al interconnects. The successful fabrication of working devices indicates that the laser activated deposition technique is compatible with standard photolithographic patterning schemes and may provide a means for simplifying integrated circuit fabrication.
Direct Writing of Al on Si by UV Exposure Prior to Laser-Assisted CVD
Authors: Bouree J. E. , Flicstein J. , Nissim Y. I. 
Published: March 2011

AbstractPhotodissociation of trimethylaluminum molecules with a UV lamp is shown to be an effective technique for predisposing the irradiated silicon surface prior to subsequent aluminum film growth via visible laser induced pyrolysis. The Al deposits thus obtained are carbon contamination free. The UV exposure time needed for the onset of Al nucleation and growth is deduced from an in situ laser reflectometry technique. Direct laser writing is obtained using this two-step process and a microscopic analysis of the lines is made in correlation with the experimental procedure.
UV Multiphoton Dissociation of Group VIB Hexacarbonyls and Derivatives
Authors: Tyndall George W. , Jackson Robert L. 
Published: March 2011

AbstractFormation of electronically excited metal atoms via excimer laser multiphoton dissociation of Cr(CO)6, C6H6Cr(CO)3, and Mo(CO)6 has been examined in the gas phase. The dissociation mechanism was studied by determining the laserfluence- dependence and buffer-gas-pressure dependence of the metal atom emission intensity. Each of these species was found to form metal atoms via two-photon and three-photon dissociation processes. The data suggest that dissociation occurs by both direct and sequential processes.
Rapid Formation of Beryllium Nitride and Beryllium Oxide by Excimer Laser Irradiation of Samples Immersed in Liquids
Authors: Dijkkamp D. , Wu X. D. , Chan Siu-Wai , Venkatesan T. 
Published: March 2011

AbstractExcimer laser induced rapid formation of nitride and oxide layers on beryllium samples immersed in liquid nitrogen and water, resp., has been studied. From Rutherford backscattering spectra the amounts of incorporated nitrogen and oxygen were determined. In addition, scanning electron microscopy was used to study the morphology of the irradiated surface and compound formation was confirmed by X-ray diffraction. Our results show that extremely rapid reaction takes place when the laser energy is sufficient to melt the beryllium surface. The amount of reaction is found to be proportional to both the energy density and the number of laser shots, until a nearly stoichiometric layer of Be3N2 or BeO is formed at the surface, at which point the reaction saturates. Growth rates on the order 20 nm per shot are deduced from the data, which is orders of magnitude higher than those achieved by conventional means.
Room Temperature Growth of Silicon Dioxide Using a Low Energy Ion Beam
Authors: Todorov S. S. , Fossum E. R. 
Published: March 2011

AbstractUltra-thin films of silicon dioxide are formed on silicon surfaces at room temperature by direct bombardment with an oxygen-containing ion beam at energies of 150 eV or less. The process of film growth is studied.through ellipsometric measurements of their properties as a function of ion energy and dose, oxygen partial pressure and substrate temperature. Typical oxide thicknesses of the order of 50 Å are obtained by three minute or longer exposures to beams of current density 135 μA/cm2. Ion-beam grown oxides are compared to conventional thin oxide films grown at elevated temperatures and show the same stoichiometry. The growth rate decreases rapidly after a continuous oxide film has been formed. Performing the ion bombardment at elevated substrate temperatures leads to only small enhancement of the oxide growth indicating non-thermally driven reaction kinetics.
Photochemical Dry Etching of Semiconductors and its Relationship to Semiconductor Electronic Properties
Authors: Ashby Carol I. H. 
Published: March 2011

AbstractThe general utility and selectivity of photochemical dry etching processes which require direct participation of photogenerated carriers is largely determined by the electronic properties of the semiconductor. The laser which is used to produce the carriers responsible for etching can also provide in situ measurement of some of the important electronic properties which influence the etching process.
Laser-Assisted Selective Chemical Etching of GaAs/AlGaAs Layered Structures
Authors: Brown R. T. , Black J. F. , Sacks R. N. , Peterson G. G. , Leonberger F. J. 
Published: March 2011

AbstractLaser-assisted etching techniques have been developed for alloyselective patterning of GaAs/AlGaAs layered structures. Such techniques are potentially very important for the fabrication of a large variety of heterostructure devices. Studies have been carried out with several liquid etchants and have utilized a CW dye laser tuned to a wavelength above the band edge of GaAs, but below that of the AlGaAs layer (e.g., λ = 0.85 μm) to etch GaAs. Using the laser focal spot to spatially define the etched area, features exhibiting very smooth interface surfaces were produced in MBE-grown epitaxial layers. A high degree of selectivity for GaAs over A1(0.4)Ga(0.6)As, low background etch rates, and high feature etch rates (> 2 μm/min) were demonstrated. Patterned etching with AZ 1350J photoresist exhibited good pattern resolution and nearly vertical sidewall profiles. Etchant mixtures of dilute H2S04:H202:H20 and HNO3:H20 produced qualitatively different results, with the HNO3:H20 mixture exhibiting a tendency to leave a residual GaAs layer at the interface, even for long etch times. Surface analysis techniques, including Auger spectroscopy, profilometry, and interference contrast microscopy have been used to characterize the etched structures, and a simplified analytical model has been used to predict the qualitative dependence of etch rate on layer thickness.
Etching of LiNbO3 by Laser-Driven Fusion of Salts
Authors: Ashby C. I. H. , Brannon P. J. 
Published: March 2011

AbstractLithium niobate exhibits low reactivity with most chemical etchants. Consequently, etching a LiNbO3 surface to produce optical structures such as ridge waveguides or grooves for fiber coupling normally requires relatively slow processes such as ion milling. We have developed a laser-driven chemical etching process for etching highly unreactive ionic solids based on the fusion of salts In the molten phase and show that the etch rate can be more than 100 times faster than ion milling rates. This process involves spatially localized melting of LiNbO3 by high-power density laser pulses with photon energies in excess of the band gap of LiNbO3. While molten, LiNbO3 undergoes reaction with a surface coating of KF to form niobium oxyfluoride anions by fusion of the salts. The resulting solid is highly water soluble. The insolubility of LiNbO3 permits subsequent removal of only the irradiated area by rinsing in water. Surface morphology is determined by laser power density. The process exhibits a wavelength dependence.
Surface Fluorination of Polyimide Thin Films by CF4 + O2 Reactive Ion Beam Etching
Authors: Vanderlinde William E. , Ruoff Arthur L. 
Published: March 2011

AbstractSurface fluorination of polyimide thin films during CF4 + O2 reactive ion beam etching (RIBE) was investigated. The removal of the fluorinated layer by a subsequent oxygen ion beam etch was also studied. Electron spectroscopy for chemical analysis (ESCA) and Rutherford backscattering spectrometry (RBS) detected a fluorinated surface layer on the order of 100 A thick. Fluorine atom concentration in the surface of the film (as measured by RBS) and the etch rate of the film were measured as a function of several experimental parameters: ion energy, ion current density, etch time, and gas composition. The results are compared with theoretical predictions of the total number of fluorine atoms retained in the film after etching.
Control of the Surface Reactivity of the Si(100) Surface
Authors: Yates John T. , Bozack M. J. , Muehlhoff L. , Choyke W. J. 
Published: March 2011

AbstractWe have used molecular beam methods and temperature programmed desorption to probe the reaction of several hydrocarbons with the Si(100) surface at cryogenic temperatures. It has been found that the kinetics of the surface reaction with the C=C bond can be strongly influenced by the production of active surface sites using prebombardment with Ar ions. The chemistry of the adsorbate is also influenced by electron bombardment of the adsorbed layer. Conversely, capping of active sites with atomic hydrogen retards the kinetics of the surface reaction. This work forms a first step in using the methods of surface kinetics and spectroscopy to probe the details of the elementary steps at work in chemical vapor deposition and plasma vapor deposition, leading to the production of SiC films.
Production of Electronically Excited P2 and in from ArF Excimer Laser Irradiation of InP
Authors: Donnelly V. M. , McCrary V. R. , Brasen D. 
Published: March 2011

AbstractWe have investigated the decomposition of single-crystal InP surfaces irradiated by a 193 nm ArF excimer laser. These studies provide insight into mechanisms of thermal decomposition, surface diffusion and epitaxy. Pulsed laser exposure leads to evolution of P2 from the surface which is detected by resonance fluorescence resulting from a fortuitous overlap of the v″ = 0 with the laser frequency. P2-evolution occurs above a threshold fluence of 0.12 J/cm2 and lags the peak laser intensity by ∼20 nsec. These observations are explained by a thermally activated decomposition mechanism, as opposed to any direct, photochemical ejection process. Peak surface temperatures have been calculated and are used to predict P2 yields as a function of fluence and time which are in good agreement with experiments. These findings are also discussed in relation to previous studies of excimer laser stimulated growth of InP.
Crystallographic Effects on the Photoelectrochemical Etching of Gratings in Compound Semiconductors
Authors: Carrabba Michael M. , Nguyen Nguyet M. , Rauh R. David 
Published: March 2011

AbstractGrooves have been etched photoelectrochemically into a (100) n-GaAs surface using a 100 cycle/mm grating mask to define the illuminated area. The degree of mask undercutting and the shape of the groove bottom are shown to be functions of doping density and crystallographic orientation. High doping density gives rise to reduced undercutting, presumably due to a lesser extent of surface diffusion of photogenerated holes.
Laser-Induced Thermal Decomposition of Platinum Metallo-Organic Films
Authors: Gupta A. , Sausa R. C. , White J. R. 
Published: March 2011

AbstractThe focused output from an argon ion laser (514 nm) has been used to pattern micron-size platinum features by decomposition of spun-on metallo-organic film on quartz substrate. The role of laser power and energy density on the thermal decomposition of the film is studied using pulsed and cw laser irradiation. Transient reflectivity has been used as a probe to study the reaction steps involved in the decomposition of the metallo-organic containing film. Preliminary results on the use of the platinum features as seed layer for electroless copper plating is presented.
Mechanical Property Determination for Supported Polymer Films using Double Bending Beams
Authors: Han B. J. , Tong H. M. , Saenger K. , Gryte Carl C. 
Published: March 2011

ABSTRACTA double-bending-beam technique has been developed to determine the mechanical properties (e.g., the elastic stiffness parameter and the in-plane coefficient of thermal expansion) of thin polymer films during thermal cycling. The mechanical properties of poly(methyl methacrylate) and a polyimide have been determined from the combined stress-temperature relationships of identical polymer films coated on two rigid beams (each with a distinctly different Young's modulus and coefficient of thermal expansion). The measured mechanical properties were found to agree with data obtained using conventional techniques. The double-bending-beam technique can be applied to a wide variety of dry and wet processing situations involving thin polymer films.
Evidence for Polycrystalline Si Surface Layer Formation by Argon Implantation and its Passivation by Atomic Hydrogen
Authors: Chien H.-C. , Ashok S. , Slowik J. H. 
Published: March 2011

ABSTRACTAl/p-Si Schottky barriers formed on wafers implanted with 10–20 keV Ar exhibit low-temperature electrical properties characteristic of grain boun1dary transport Subsequent low-energy (0.4 keV), high fluence ( ∼ IOE18 cm−2) H implant is found to passivate the grain boundaries of the Ar implant-induced microcrystals. Extremely high Al/p-Si Schottky barrier heights are obtained following the dual implants, and deep level transient spectroscopy (DLTS) measurements reveal that H also alters the properties of traps introduced by the Ar implant, thus improving the diode characteristics.
A Theoretical Study of the Etchback Planarization Process
Authors: Kuo Yue 
Published: March 2011

ABSTRACTA computer modeling method was used to study various factors such as the etch time, the degree of planarization of the sacrificial layer, the original surface shape of the sacrificial layer, the etch ratio, and the original oxide step shape, that directly affect the topography of an etchback planarized surface.
Nitride, Nitrided Oxide and Oxidized Nitride for Thin Dielectrics
Authors: Tay S. P. , Kalnitsky A. , Ellul J. P. 
Published: March 2011

ABSTRACTIn this paper, comparisons of material and electrical parameters between qate and interpoly dielectrics consistinq of thermal oxides, nitrides, nitrided oxides and oxidized nitrides are reported. A range of dielectrics, 5 nm to 30 nm thick, are thermally grown using a matrix of oxidation cycles, ammonia concentration and nitridation temperatures and pressures. Fabrication of polysilicon gate and interpoly capacitors is typical of industry standards. AES, RBS and ellipsometric analysis of dielectric material properties are discussed and electrical characterization results are presented.
Process-Induced Point Defects in Oxidized Silicon Structures
Authors: Caplan P. J. , Poindexter E. H. , Vasudev P. K. , Henderson R. C. 
Published: March 2011

ABSTRACTPoint defects caused by common fabrication methods may increase device susceptibility to radiation or hot carriers. In this study, defects induced by dry and wet oxidation, ion implantation, and rapid thermal annealing are examined by electron paramagnetic resonance. A brief 02 anneal at 900°C is found to be more effective than N2 in transformation of a steam-grown oxide interface to that of a dry oxide. A N2 anneal at 450 °C has little effect, and must be extended to about 2 hr to dessicate the interface. Implants of B, P, and BF2 have no direct effect on the interface, but activation anneal in N2 at 900°C produced large Pb concentration. Implant generates E′ centers in the oxide, which are eliminated by the activation. Rapid thermal annealing below 600°C reduces interface traps, but increases them above 700°C, with severe oxide and interface damage at 1100 °C. Electron-beam lithography and plasma- or ion-beam etching are discussed briefly.