bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Solute Additions on Electromigration in Aluminum
Authors: Kim Choong-Un , Morris J. W. , Génin F. Y. , Fluss M. J.
Published: April 2011

This study investigates the effect of solute additions on electromigration in Al-based thin film binary alloys. The “cross-strip” technique was used to observe solute electromigration and its influence on Al electromigration. The results of electromigration tests on five alloy additions, Ag, Au, Cu, Pd and Ni, are presented. It is concluded that beneficial solutes have two characteristics. First, they have a large, negative effective valence (Z**). Second, they have sufficient solubility in Al at test temperature to provide a reservoir of mobile atoms. Ag and Au are relatively ineffective because of their low effective valence. Pd and Ni appears to be relatively ineffective because of their low solubility at test temperature. Only Cu satisfies both criteria.
Copper Diffusion Into Aluminum-Silicon Metallizations by Accelerated Thermal and Electrical Stressing
Authors: Ramseyer G. O. , Walsh L. H. , Beasock J. V. , Helbig H. F. , Lacoe R. C. , Brown S.
Published: April 2011

Patterned 930 nm Al(1%-Si) interconnects over 147 nm of Cu were electromigration lifetime tested at 1.0–1.5 × 105 A/cm2 at 250 °C. The morphology of the surfaces of the electromigrated stripes with different line widths and times to failure were characterized by atomic force microscopy, and changes in surface roughness were compared. The diffusion of copper into the electromigrated aluminum stripes was determined by depth profiling using Auger electron spectroscopy. In particular, areas where hillocks formed were examined and compared to areas of median roughness.
Residual Gas Phase Contamination of Al-Cu Alloy Films and its Effect on Electromigration Behavior
Authors: Hashim Imran , Raaijmakers Ivo J. , Adler Glen , Sidhwa Ardy , Chopra Sudhir
Published: April 2011

The major sources of impurities in sputtered Al alloy films for interconnects, prepared by physical vapor deposition include those originating from the target material, residual gases present in the vacuum system, and those introduced through the gas delivery system. In this study, we report the effect of impurities incorporated from residual gases present in vacuum systems on the electromigration performance of 0.6 μm wide Al-l%Cu lines. Controlled leaks of isotope gases H2O18, N215, O218, and C13H4, in 10−6 10−9 Torr range, were introduced into a PVD tool during the sputtering process. Using these isotope gases, the impurities originating from residual gases were distinguished from those originating from other sources of impurities. The sputtering target was found to be the major source of H and O impurities in the film, whereas N atoms are introduced in the film mainly through the gas phase. Furthermore, N atoms in the film were found to affect its electromigration behaviour to a larger extent than O and H.
30 Years of Electromigration Research: A Grand Masters' Perspective
Authors: Lloyd J. R.
Published: April 2011

At the MRS Spring Meeting in San Francisco this year, a special historical session was held in the symposium on Materials Reliability in Microelectronics to reflect upon thirty years of research into electromigration as a failure mode in integrated circuits. Six of the original “discoverers” of electromigration as a reliability issue were invited to speak of their work and to relate stories of the early days of these historic efforts.
Generation of Hole Traps in Silicon Dioxide Under Fowler-Nordheim Stress
Authors: Brożek T. , Chan Y. D. , Viswanathan C. R.
Published: April 2011

High field electron injection in silicon oxide layers in metal-oxide-semiconductor system is widely known to degrade thin silicon oxide layers and the silicon-oxide interface, eventually leading to catastrophic oxide breakdown. In this work we report generation of hole traps under high-field stressing of thermal silicon dioxide layers on silicon. Excess hole trapping on newly generated hole traps is observed by substrate hot-hole injection in 9 nm oxide PMOS transistors after high-field Fowler-Nordheim stress followed by standard post-metallization annealing in nitrogen. The concentration of generated traps is stress-polarity dependent and increases with electron fluence during degrading stress. Relaxation behavior under switching oxide fields indicates that the nature of hole trapping sites is different from anomalous positive charge centers. A correlation of density of generated hole traps with the amount of generated electron traps shows that both types of traps are effectively generated in the oxide layer under Fowler-Nordheim tunneling electron injection.
Transient Photocurrent Spectroscopy of Trap Levels in Ultra-Thin SiO2 Films
Authors: Miura Y. , Fujieda S.
Published: April 2011

Stress-induced trap levels near Si/SiO2 interfaces for MOS diodes with 10 imi-thick oxides are investigated by measuring the transient photocurrent, which depends on the incident photon energy. The electron trap levels are filled by tunneling injection, and the electrons are depopulated by monochromatic light irradiation. The transient photocurrent, which is measured as an external circuit current, decays exponentially with time. Based on a proposed detrapping model, the optical cross section is estimated to be about 1×10−17 cm2 for hv=2−3 eV. The obtained photo-accessible trap density has a broad distribution at around hv=2.5 eV.
Front-End Integration Effects on Gate Oxide Quality
Authors: Lin F. , Ajuria S. A. , Ilderem V. , Masquelier M. P.
Published: April 2011

In this paper, the impact of several front-end processing steps (up to gate oxidation) on gate oxide integrity (GOI) is evaluated. In PBL isolation processing, the use of as-deposited amorphous silicon (a-Si), subsequently annealed during nitride deposition, results in better structural and electrical properties compared to as-deposited polysilicon or as-deposited a-Si with an extra anneal step prior to nitride deposition. Thicker or dual sacrificial schemes exhibit improved gate oxide low voltage breakdown and charge-to-breakdown. Dilute RCA chemistries during pre-gate cleaning produce equal or better surfaces for gate oxidation than the conventional non-dilute RCA with less chemical usage. As gate oxides are scaled below 100Å, lowering gate oxidation temperature is proven to result in far better gate oxide quality than maintaining process temperatures at or above 900°C and diluting oxygen in either argon or nitrogen.
A Novel Method For Studying Degradation Related To Plasma Processing Of Silicon Wafers
Authors: Lagowski J. , Hofl A. , Jastrzebski L. , Edelman P. , Esry T.
Published: April 2011

A new generation of monitoring tools based on oxide potential and surface photovoltage measurements offers real-time, non-contact diagnostics of plasma damage, especially dielectric charge build-up, radiation damage, and heavy metal contamination. The approach relies on reusable, 10 00Åoxide monitor wafers rather than test structures. The technique generates whole wafer maps powerful for correlating plasma damage with plasma equipment characteristics.
Non-Destructive Assessment Of Semiconductor Carrier Lifetime Using Photothermal Radiometry
Authors: Amirhaghi S. , Kenyon A. J. , Federighi M. , Pitt C. W.
Published: April 2011

Of crucial importance to all areas of the microelectronics industry is the characterisation of silicon wafer quality. An important indicator of this is carrier lifetime, and a convenient non-destructive method for its measurement is Pholothermal Radiometry. This involves the photo-generation within a semiconductor sample of electron-hole pairs. Periodic generation of carriers leads to modulation of free-carrier absorption of mid-ir radiation provided by a black body source. The fr-radiation detected from the photo-excited region is inversely proportional to the optically induced carrier density. As the modulation frequency is increased, a point is reached at which the photo-generated carriers no longer have sufficient time to decay between pulses. This frequency is dependent on the carrier lifetime. We present a description of the Photothermal Radiometric lifetime scanning instrument built at UCL. This instrument offers an accurate method for producing detailed maps of carrier lifetime across whole or part wafers. The problem of surface-state effects has been addressed by employing a broad-band uv source to optically fill the surface states of the sample under investigation. The instrument is capable of producing maps of lifetime variation with 0.5 mm resolution. Alternatively, for selected points on a wafer, the instrument can generate detailed frequercy scans of free-carrier absorption. From these, it is possible to obtain information on surface recombination velocity and diffusion length.
An Analysis Of Void Nucleation In Passivated Interconnect Lines Due To Vacancy Condensation And Interface Contamination
Authors: Gleixner R. J. , Nix W. D.
Published: April 2011

Nucleation of voids due to vacancy condensation in passivated aluminum lines is analyzed within the context of classical nucleation theory. A discussion of sources of hydrostatic tensile stress in such lines provides a reasonable upper limit of 2 GPa. The void nucleation rate is then calculated at various sites within the line. Results suggest that nucleation rates are far too low to account for observed rates of voiding. Void nucleation at a flaw at the line/passivation interface is then considered as an alternative nucleation mechanism. Such flaws may be created by contaminants introduced during fabrication of the line. In this case, nucleation is feasible at greatly reduced stresses, well within the observed values. Furthermore, a simple model of void growth indicates that a fast atomic transport path, such as a grain boundary, must intersect the void for an appreciable growth rate. These results suggest that void nucleation in aluminum interconnect lines occurs at flaws at the sidewall of the line and that stress-induced and electromigration-induced voiding can be controlled by eliminating interfacial contamination.
Measurements Of Stress Evolution During Thin Film Deposition
Authors: Chason E. , Floro J. A.
Published: April 2011

We have developed a technique for measuring thin film stress during growth by monitoring the wafer curvature. By measuring the deflection of multiple parallel laser beams with a CCD detector, the sensitivity to vibration is reduced and a radius of curvature limit of 4 km has been obtained in situ. This technique also enables us to obtain a 2-dimensional profile of the surface curvature from the simultaneous reflection of a rectangular array of beams. Results from the growth of SiGe alloy films are presented to demonstrate the unique information that can be obtained during growth.
Isothermal Stress Relaxation In Al, AlCu and AlVPd Films
Authors: Lokker J. P. , Jongste J. F. , Janssen G. C. A. M. , Radelaar S.
Published: April 2011

Mechanical stress and its relaxation in aluminum metallization in integrated circuits (IC) are a major concern for the reliability of the material. It is known that adding Cu improves the reliability but complicates plasma etching and increases corrosion sensitivity. The mechanical behavior of AIVPd, AlCu and Al blanket films is investigated by wafer curvature measurements. During thermal cycling between 50°C and 400°C the highest tensile stress is found in AIVPd. In a subsequent experiment, the cooling was interrupted at several temperatures to investigate the stress behavior during an eight hour isothermal treatment. Isothermal stress relaxation has been observed in the three types of films and is discussed.
Electromigration Characterization for Multilevel Metallizations using Textured AlCu
Authors: Ting Larry M. , Hong Qi-Zhong
Published: April 2011

Electromigration lifetime dependence on crystallographic texture for AlCu interconnects is determined. It is found that enhancement of AlCu texture at <111> orientation improves EM endurance. But this beneficial effect is limited after a certain level of texture enhancement is reached. The effect of lifetime improvement is proved to result from a decrease in atomic diffusivity. Saturation of the lifetime improvement effect for highly textured AlCu indicates a change in the main diffusion mechanism for electromigration, possibly from the regular grain boundary diffusion to diffusion through edge dislocations.
Improvement in Platinum Silicidation for 0.8 m BICMOS Process
Authors: Parikh Suketu , Modi Gaurang , Nagalingam Samuel
Published: April 2011

Platinum Silicidation involves interdiffusion of Pt and Si which finally results in the formation of PtSi. The quality of Platinum Silicide strongly influences the electrical properties such as schottky barrier height and its contact resistance. We demonstrate a two step process using rapid thermal processing (RTP) with 400 °C 30 sec silicidation in N2 atmosphere, followed by 500 °C 30 sec oxidation in O2/N2 mix. The two temperature step process gave better electrical and material characteristics compared to a single step silicidation at 400°C with N2/O2 mix. The two step silicidation recipe also had lower sheet resistance, no unreacted platinum (based on X-ray diffraction analysis) and uniform SiO2 layer (based on Auger Electron Specrtroscopy) on top of silicide, to protect it from aqua regia.
Rapid Thermal Magnetic Annealing: A Novel Technique in Thin-Film Recording Head Production?
Authors: Roozeboom Fred , Ruigrok Jaap J. M. , Klaassens Wilco , Kegel Herbert , Falter Manfred , Walk Heinrich
Published: April 2011

A new emerging application area for Rapid Thermal Annealing (RTA) may be in the manufacturing of thin-film recording heads for high-density (hard disk drive, video, audio and data tape) recording. To that end we co-designed a new commercial reactor with an external electromagnet to anneal thin soft-magnetic films (nanocrystalline iron alloys) deposited on ceramic wafers of up to 150 mm diameter. The electromagnet generates a field controllable up to 660 Oe (52.8 kA/m). It is completely homogeneous in direction (i.e. fully parallel field lines) across the entire wafer area. Wafers can be annealed either statically, or while rotating (up to 120 rpm), or in two subsequent heating steps with a 90° wafer rotation in between.

Nanocrystalline Fe-Nb-Si-N layers have better soft-magnetic properties after Rapid Thermal Magnetic Annealing (RTMA) in a static magnetic field than after conventional furnace annealing in a static field. Temperature-programmed resistance measurements and Transmission Electron Microscopy (TEM) show that the first nanocrystalline, body-centered cubic iron grains start growing already as of 350 °C from the amorphous as-deposited film, whereas the desired segregation of NbN starts only as of 530°C. RTA can be used to promote the kinetics of the segregation of NbN along the boundaries of nanocrystalline iron nuclei. This prevents the iron grains from further growth: with RTMA the iron alloys show smaller nanocrystalline iron particles (order: 10 nm) as observed by TEM.
Monte Carlo Thermal Model of an Integrating Light Pipe for Rapid Thermal Processing
Authors: Thomas J. C. , Dewitt D. P.
Published: April 2011

A Monte Carlo model is developed to simulate transient wafer heating as a function of system parameters in a kaleidoscope- or integrating light-pipe type cavity with square cross-section. Trends in wafer temperature uniformity are examined as a function of length-to-width ratio, cavity width, and the number of heating lamps. The effect on temperature determination by a radiometer placed in the bottom end wall of the cavity is simulated.
Electron Cyclotron Resonance in Strained Si and Si0.94Ge0.06 Channels on Relaxed Si0.62Ge0.38 Buffers Grown by Rapid Thermal Chemical Vapor Deposition
Authors: Liu C. W. , Venkataramana V.
Published: April 2011

We report the far-infrared measurements of the electron cyclotron resonance absorption in n-type Si/Si0. 62Ge0.38 and Si0.94Ge0.06 /Si0. 62Ge0.38 modulation- doped heterostructures grown by rapid thermal chemical vapor deposition. The strained Si and Si0.94Ge0.06 channels were grown on relaxed Si0.62Ge0.38 buffer layers, which consist of 0.6 μm uniform Si0.62Ge0.38 layers and 0.5 μm compositionally graded relaxed SiGe layers from 0% Ge to 38 % Ge. The buffer layers were annealed at 800 °C for 1 hr to obtain complete relaxation. The samples had 100 Å spacers and 300 Å 2×1019 cm-3 n-type supply layers on the tops of the 75 Å channels. The far-infrared measurements of electron cyclotron resonance were performed at 4K with the magnetic field of 4 – 8 Tesla. The effective masses determined from the slope of center frequency of absorption peak vs applied magnetic field plot are 0.20 mo and 0.19 mo for the two dimensional electron gases in the Si and Si0.94Ge0.06 channels, respectively. The Si effective mass is very close to that of two dimensional electron gas in Si MOSFET (0.198mo). The electron effective mass of Si0.94Ge0.06 is reported for the first time and about 5 % lower than that of pure Si.
Nonlinear Model Reduction Strategies for Rapid Thermal Processing Systems
Authors: Banerjee Suman , Cole J. Vernon , Jensen Klavs F. , Emami-Naeni A.
Published: April 2011

This paper presents a systematic way of developing low order nonlinear models from physically- based, large scale finite element models of rapid thermal processing (RTP) systems. The low order model is extracted from transient results of the finite element model using the proper orthogonal decomposition (POD) method. Eigenfunctions obtained from the POD method are used as basis functions in spectral Galerkin expansions of partial differential equations solved by the finite element model to generate the reduced models. Simulation results demonstrate good agreement with steady state and transient data generated from the finite element model.
Application of Holographic Interferometry to Flow Pattern Visualization in an RTCVD Reactor
Authors: Rainova Yu. P. , Pezoldt J. , Antonenko K. I. , Eichhom G.
Published: April 2011

This paper presents the development of an experimental technique for the reception of holographic interferograms of H2 and Ar flows in a RTCVD reactor with a complex geometry. The obtained holographic patterns were analyzed for the reconstruction of the gas flow in the RTCVD reactor. The fringe patterns showing the gas density distributions were recalculated into temperature distributions. Experimental results were compared with the predicted flow field.
Accurate Estimation of Radiative and Convective Losses in a Multizone RTP Reactor
Authors: Nagabushnam R. V. , Singh R. K. , Sharan S. , Sandhu G.
Published: April 2011

We have developed a methodology aimed at accurately determining the various forms of energy transfer(convective loss, radiative loss and absorption of lamp energy by the wafer)occurring in any advanced RTP system, based on basic system identification experiments and simple 3- dimensional physical model depicting the heat transfer processes. The identification experiments help in estimating the uncertain system dependent factors which characterize the various forms of energy transfer, which may be otherwise difficult to calculate on pure theoretical basis. This methodology forms the basic building block of our effort to develop a tool which can predict the temperature distribution across the wafer in a realistic way. This tool can be used both as a wafer temperature control algorithm in any advanced RTP system by incorporating more accurate system impedance parameters(convective and radiative loss) as well as by an end user to calculate the required power level settings to various lamp zones to attain reasonable temperature uniformity for a RTP system which does not have a dynamic con-rol.
Preparation of YBCO Platelets and Films by Mod and Microwave Heating
Authors: Manfredotti C. , Castighioni M. , Polesello P. , Rizzi N. , Volpe P.
Published: April 2011

Metal Organic Deposition (MOD) technique, which represents a flexible method for obtaining both platelets and films of YBCO, is based on baking, pyrolyzing and annealing stages of neodecanoates solutions. The annealing step is generally very long. The whole annealing stage can be simply substituted by a heat treatment (about 1 h) in a commercial microwave (MW) oven, followed by a 15 min. annealing at 900°C in a resistive furnace without oxygenation. With this process, YBCO platelets, films and wires were obtained starting from powders prepared by MO (Metal-Oxide). XRD patterns are indicative of a strong texturing by the evidence of (003) and (005) lines. By the same technique, YBCO films were prepared by spray deposition on A12O 3 for a total thickness of about 5 μm, each spray step, of 1 gm, was followed by 5 min pyrolysis at 500 °C and 1 h MW annealing.

The MW technique was also used for preparation of quartz and ceramic fibers covered by YBCO.
Novel Microstructures in Microwave Sintered Silicon Nitride
Authors: Brito M. E. , Hirao K. , Toriyama M. , Hirota M.
Published: April 2011

Preliminary results on microwave sintering of seeded silicon nitride show that a well defined bi-modal grain size distribution is attainable in Si3N4-Y2O3-Al2O 3-MgO sintered bodies by microwave sintering at 28 GHz of materials seeded with ß-Si3N4 particles (2 vol. %). A positive effect on the mechanical performance is anticipated for these microstructurally controlled silicon nitride ceramics
A comparison of mm-wave Sintering and Fast Conventional Sintering of Nanocrystalline Al2O3
Authors: Link G. , Ivanov V. , Paranin S. , Khrustov V. , Böhme R. , Müller G. , Schumacher G. , Thumm M. , Weisenburger A.
Published: April 2011

The phase transformation and densification behavior under high power millimeter-wave (mm-wave) radiation of a 30 GHz gyrotron and during fast conventional sintering of nanocrystalline γ-A12O3 powder have been investigated and compared. The powder used for compacts was synthesized from aluminum metal by application of the exploding wire technique in an oxidizing atmosphere. The particle size distribution of this powder has a maximum at about 20 nm. Magnetic pulse technique was applied for the compression of samples up to 80% of the theoretical density (TD). Both mm-wave sintering and fast firing in a conventional electrical resistance furnace enable the densification and a complete phase transformation into α-A12O3 already at a temperature of approximately 1150 %C. The average grain size of the sintered ceramic is in the range of 50 to 100 nm. With mm-waves densification starts at about 50 °C lower temperatures compared to conventional techniques and higher final densities were obtained already at 150°C lower temperatures.
Adhesive Bonding Via Exposure to Microwave Radiation and Resulting Mechanical Evaluation
Authors: Paulauskas Felix L. , Meek Thomas T. , Warren C. David
Published: April 2011

Adhesive bonding/joining through microwave radiation curing has been evaluated as an alternative processing technology. This technique significantly reduces the required curing time for the adhesive while maintaining equivalent physical characteristics as the adhesive material is polymerized (crosslinked). This results in an improvement in the economics of the process. Testing of samples cured via microwave radiation for evaluation of mechanical properties indicated that the obtained values from the single lap-shear test are in the range of the conventionally cured samples. In general, the ultimate tensile strength, OB, for the microwave processed samples subjected to this single lap-shear test was slightly higher than for conventionally cured samples. This technology shows promise for being applicable to a wide range of high volume, consumer goods industries, where plastics and polymer composites will be processed.
Overview of Comnonent and Device Characterization
Authors: Rytting Doug
Published: April 2011

The electronics market is constantly pushing the state of the art in design to reduce cost, size, weight, and power consumption. New designs are emerging causing rapid changes in technology driving high design turnover. This drives the need for component and material measurements that will reduced design cycles and time to market. In the design and measurement of linear devices, error corrected S-parameters are traditionally measured with a network analyzer. the network analyzer combines magnitude with phase measurements for improved accuracy. Time domain techniques are used to get a better physical understanding of the device characteristics. Error correction procedures have been improved to provide high accuracy and ease of use. New methods to measure impedance results in high precision capacitor and inductor models necessary for both surface mount and integrated circuit applications. Note: In the following paper the relevant text follows each slide.
A New Approach For Dielectric Measurements At High Temperatures
Authors: Groffils C. , Luypaert P. J. , Zhou Y. , Biest O. Van der
Published: April 2011

Most of the algorithms for cavity dielectric measurements use a full network frequency scan for the perturbation method. At high temperature the measurement points in one frequency scan will have different temperatures due to the fast cooling of the sample inside the cold cavity. This paper presents a new approach for the perturbation method to measure dielectric constants at high temperatures with a two port, two piston cylindrical cavity and external furnace. Special features of this cavity are the possibility to work with different modes and different relative positions of the coupling aperture.

The dielectric properties are extracted from the full sets of S-parameters for two successive frequency points corresponding to approximately the same temperatures. An extraction algorithm is developed and programmed.
Characterization Of Thin Semiconductor Films For (Opto)Electronic Applications
Authors: Elmiger J. R. , Feist H. , Kunst M.
Published: April 2011

A simple set-up to measure the transient photoconductivity in the microwave frequency range is presented. The effective mobility is derived from the end of pulse transient photoconductivity. This can be used for the characterization of semiconductor films. Examples of measurements on a-Si:H films are given.
An Overview Of Electromagnetic Modeling Of Single- And Multi-Mode Applicators At Emr Microwave Technology Corporation
Authors: Tranquilla J. M. , Al-Rizzo H. M. , Clark K. G.
Published: April 2011

This paper examines the design aspects and numerical modeling of single- and multi-mode, high power, microwave resonant cavity applicators. A novel numerical electromagnetic modeling approach, based on the finite difference solution of Maxwell's equations in the time domain, is utilized taking into account the finite conductivity and thickness of the cavity walls. Results obtained from the model enable an unambiguous choice of the optimum iris size for critical coupling; shape, dimension, orientation and number of radiating elements for a prescribed irradiation pattern of slotted waveguide feeds as well as dimensions and excitation mechanism of multimode cavities. The model also allows the evaluation of the volumetric distribution of the microwave energy at any point inside the load and may eventually be used to determine the dynamic transient temperature profiles induced during the curing process.
Influence of Specific Absorbed Microwave Power on Activation Energy of Densification in Ceramic Materials
Authors: Bykov Y. , Eremeev A. , Holoptsev V.
Published: April 2011

Correlation between the rate of densification in powder ceramic materials and specific absorbed microwave power is determined by the experimental method. The approach is based on a comparison of the densification curves obtained at different rates of heating. The changes in the ramping rate are provided by varying the microwave power fed into the microwave furnace. Using the energy balance for the microwave heated samples, the correlation between the apparent energy of activation at the initial stage of densification and the value of the specific microwave power absorbed in heated materials are found. The experiments with silicon nitride-based ceramics allowed to determine the reduction in the value of the activation energy resulted from an increase in the specific absorbed microwave power.
Grain Growth Behavior During Microwave Annealing of Silicon Nitride
Authors: Hirota M. , Brito M. E. , Hirao K. , Watari K. , Toriyama M. , Nagaoka T.
Published: April 2011

A comparative study of grain growth behavior in silicon nitride under conventional and microwave annealing is presented. Microwave annealed specimens showed a faster growth rate as indicated by the quantitative microstructural analysis. The phenomenon was used in combination with seeding techniques to develop a silicon nitride exhibiting a bi-modal microstructure. Microwave annealing was carried out using a microwave radiation frequency of 28 GHz.
Observation of an Electromagnetically Driven Temperature Wave in Porous Zinc Oxide During Microwave Heating
Authors: Dadon D. , Gershon D. , Carmel Y. , Rybakov K. I. , Hutcheon R. , Birman A. , Martin L. P. , Calame J. , Levush B. , Rosen M.
Published: April 2011

Propagation of a sharp temperature wave was observed during microwave heating of porous zinc oxide in nitrogen and argon atmospheres. This wave initiated from the center of the sample and traveled at an average velocity of 0.2 cm/min towards its surface. This temperature wave was attributed to an anomalous peak in the imaginary part of the complex permittivity possibly caused by desorption of chemisorbed oxygen from the surfaces of ZnO crystallites.
Millimeter Wave Material Separation System
Authors: Birken S. , Birken K. , Connor K. , Scheitrum G.
Published: April 2011

A new process is in development that uses high power millimeter wave energy to separate specific components from a composite material stream. The component to be separated from the material stream must have a combination of high loss tangent and low permittivity with respect to the other materials involved. In this case, when the material is subjected to a high power, high frequency RF source, the desired component can be vaporized and extracted without transferring significant heat to the remaining material. Since absorption increases significantly with frequency, it is important to use a millimeter wave source. A vacuum pump with sufficient pumping speed can transport the vaporized component for collection. The bulk material can either be collected or recycled through the system for further extraction.
Design of Microwave Vitrification Systems for Radioactive Waste
Authors: White T. L. , Bostick W. D. , Wilson C. T. , Schaich C. R.
Published: April 2011

Oak Ridge National Laboratory (ORNL) is involved in the research and development of highpower microwave heating systems for the vitrification of Department of Energy (DOE) radioactive sludges. Design criteria for a continuous microwave vitrification system capable of processing a surrogate filtercake sludge representative of a typical waste-water treatment operation are discussed. A prototype 915-MHz, 75-kW microwave vitrification system or “microwave melter” is described along with some early experimental results that demonstrate a 4 to I volume reduction of a surrogate ORNL filtercake sludge.
Application of Multiwavelength Pyrometry in Microwave Processing of Materials
Authors: Donnan R. S. , Samandi M.
Published: April 2011

Over the past decade microwave energy has been increasingly used in materials processing, especially for sintering and more recently for the joining of advanced ceramics. However the hostile electromagnetic and plasma environment within a high power (1–6 kW) microwave applicator poses serious problems for very accurate high temperature measurement by precluding the use of existing classes of thermometry. For instance, conventional probe-based thermometry, multiple-wavelength ratio pyrometry and even the more recently developed technologies of optical fibre thermometry by fluoroptics and radiometry, are either incompatible or of restricted application. The main aim of this paper is to propose multiwavelength pyrometry as a viable technique for wide range (500–5000 K) thermometry in hostile electromagnetic and plasma environments. After briefly reviewing the physical basis of its operation, the experimental set up of the multiwavelength pyrometer is outlined, and consists of a comparatively inexpensive low resolving power grating monochromator and a PbS infrared single element detector. Results are presented that compare the measurements during conventional/microwave heating trials, from this multiwavelength pyrometer and from a K-type thermocouple, a double-wavelength ratio pyrometer and a single wavelength pyrometer aimed at a dummy target (carbon/metal).
Transient Temperature Distributions in a Cylinder Heated by Microwaves
Authors: Jackson H. W. , Barmatz M. , Wagner P.
Published: April 2011

Transient temperature distributions were calculated for a lossy dielectric cylinder coaxially aligned in a cylindrical microwave cavity excited in a single mode. Results were obtained for sample sizes that range from fibers to large cylinders. Realistic values for temperature dependent complex dielectric constants and thermophysical properties of the samples were used. Losses in cavity walls were taken into account as were realistic thermal emissivities at all surfaces. For a fine mesh of points in time, normal mode properties and microwave power absorption profiles were evaluated using analytic expressions. Those expressions correspond to exact solutions of Maxwell's equations within the framework of a cylindrical shell model. Heating produced by the microwave absorption was included in self-consistent numerical solutions of thermal equations. In this model, both direct microwave heating and radiant heating of the sample (hybrid heating) were studied by including a lossy dielectric tube surrounding the sample. Calculated results are discussed within the context of two parametric studies. One is concerned with relative merits of microwave and hybrid heating of fibers, rods, and larger cylinders. The other is concerned with thermal runaway.
Mechanical Behavior of Microwave Processed Polymer Matrix Composites: the Effect Of The Temperature Increase Rate
Authors: Delmotte M. , Fitoussi J. , Toftegaard-Hansen J. , More C. , Jullien H. , Baptiste D.
Published: April 2011

Microwave processed glass reinforced epoxies or glass reinforced polyesters exhibit mechanical behaviors different from conventionally cured materials, relatively to tensile tests. The faster increases of temperature due to microwaves cause a competition between the matrix flow and the crosslinking reaction which can be estimated by porosity variations. Higher mechanical moduih are also obtained, because of both an effect on chemical kinetics and a more homogenous distribution of temperature in materials. Nevertheless, to provide such specific mechanical behaviors in microwave processed composite materials, a best control of the experimental pressure parameters is requested.
Microwave Annealing of Ion Implanted 6H-SiC
Authors: Gardner J. A. , Rao M. V. , Tian Y. L. , Holland O. W. , Kelner G. , Freitas J. A. , AIMAD I.
Published: April 2011

Microwave rapid thermal annealing has been utilized to remove the lattice damage caused by nitrogen (N) ion-implantation as well as to activate the dopant in 6H-SiC. Samples were annealed at temperatures as high as 1400 °C, for 10 min. Van der Pauw Hall measurements indicate an implant activation of 36%, which is similar to the value obtained for the conventional furnace annealing at 1600 °C. Good lattice quality restoration was observed in the Rutherford backscattering and photoluminescence spectra.
Deposition of Thin SiO2 Films on Polymers as a Hard – Coating using a Microwave – ECR Plasma
Authors: Sano K. , Tamamaki H. , Nomura M. , Wickramanayaka S. , Nakanishi Y. , Hatanaka Y.
Published: April 2011

SiO2 thin films were deposited on automobile plastics at low temperatures using a microwave activated ECR plasma. Oxygen was used as the plasma gas while tetraethoxysilane (TEOS) was used as the source gas which was introduced into the downstream. In the present investigation high quality SiO2 films were deposited on polycarbonate (PC) and polypropylene (PP) substrates with and without a mesh and the characteristics of hard coating films were studied. The film growth rate increases with the decrease of substrate temperature when a mesh is inserted into the plasma. The irregularities of polymer surfaces could be planarized by the deposition of 1.0 μm thick SiO2 film. The dynamic hardness of PC and PP are increased by the deposition of SiO2 film, however, films deposited on PP is seen to be cracked while that of on PC is crack-free.
Materials Characterization and Diagnosis Using Variable Frequency Microwaves
Authors: Wei J. Billy , Fathi Zak , Tucker Denise A. , Hampton Michael L. , Garard Richard S. , Lauf Robert J.
Published: April 2011

Product quality control is a crucial part of manufacturing and usually involves materials characterization and diagnosis. Though various microwave assisted nondestructive evaluation (MA-NDE) systems have been fabricated for materials inspection, none of the systems can be applied to materials within a mold or reactor. A broadband variable frequency microwave based, resonant mode MA-NDE was studied as an alternative for characterization of materials within a cavity. The main advantage of the resonant mode MA-NDE are non-intrusive and volumetric diagnosis of the material inside a mold. The principles and possible applications of the resonant mode MA-NDE are discussed. Resonant mode MA-NDE was fully demonstrated by using Vani-Wave to trace material status during microwave curing of Diglycidyl Ether of Bisphenol A (DGEBA)/Diaminodiphenylsulphone (DDS) epoxy samples.
Microwave Separation Measurements of Bulk Lifetime and Surface Recombination Velocities in Si Wafers with Various Surface Properties
Authors: Ogita Y. , Minegishi M. , Higuma H. , Shigeto M. , Yakushiji K.
Published: April 2011

The separation measurements of a bulk lifetime υo, front and back surface recombination velocities S0, Sw have been investigated for both 620 μm and 1.08 mm thick Si wafers with various surface treatments. The separation was made by applying bisurface photocoductivity decay method to the photoconductivity decay curves measured by 500 MHz microwave reflection under the bias light illumination. The bulk lifetime and the surface recombination velocities have been determined, respectively, to be 624–659 μs and 18.4–66.1 cm/s for the oxidized sliced-surface and 6285 cm/s for the sliced surface. And they have been also determined, respectively, to be 412–422 μs and <1 cm/s for the oxidized mirror polished-surface or the oxidized etched surface, 565–626 μs and 1042–1112 cm/s for the oxidized sandblasted-surface. The noncontact microwave BSPCD method with bias lights makes it possible to determine separately the bulk lifetime and surface recombination velocities in the front surface and backsurface in Si wafers with the wafer thickness for the practical use.
Heat and Mass Transport Induced by Collision Cascades
Authors: Carol A. , Alurralde M. , Saliba R. , Caro M.
Published: April 2011

Irradiation of materials with energetic particles produces changes in the microstructure that affect mechanical properties. In previous work we studied the thermal aspects of the quenching of collision cascades that involve nanoscale phase transitions between the solid and the liquid states of the target. In this work we present a rigorous treatment of these phenomena, including a detailed description of the Stefan problem in three dimensions and diffusion in thermal gradients. This approach is oriented to give a quantitative description of the influence of the primary knockon spectrum on the microstructure short after the quenching of the heat spike.
Charge State Defect Engineering of Silicon During Ion Implantation
Authors: Brown R. A. , Ravi J. , Erokhin Y. , Rozgonyi G. A. , White C. W.
Published: April 2011

The effects of in situ interventions which alter defect interactions during implantation, and thereby affect the final damage state, have been investigated. Specifically, we examined the effects of internal electric fields and charge carrier injection on damage accumulation in silicon. In the first part of this work, we implanted H or He ions into diode structures which were either reverse or forward biased during implantation. In the second part, we implanted B or Si ions into plain silicon wafers whilst illuminating them with UV light. In each case, the overall effect is one of damage reduction. Both the electric field and charge carrier injection effects may be understood as resulting from changes in defect interactions caused in part by changes to the charge state of defects formed during implantation.
Electronic Structure and Gate Capacitance-Voltage Characteristics of MBE Silicon δ-Fets
Authors: Manzoli J. E. , Hipólito O.
Published: April 2011

New implementations in MBE growth techniques allow high accuracy in δ-doping profiles in Silicon crystals. In this work we present a self-consistent numerical calculations of the electronic structure of δ-FETs, field effect transistors where electric transport channel is a quasi-two-dimensional plan of Antimonide doping in a Silicon crystal. We made the calculations to the heavy and light electrons at 77 and 300K varying the gate voltage in devices with one to three coupled deltas. We obtain the effective potential, the sub-bands and respective electronic densities, basic calculations to point at optimization of the device. We made considerations on theirs DC - capacitances and free electron density spreadings to achieve the gate-voltage best performance.
Vacancy-Type Defects in Electron and Proton Irradiated II- VI Compounds
Authors: Brunner S. , Puff W. , Mascher P. , Balogh A. G. , Baumann H.
Published: April 2011

In this contribution, we present a study aimed at investigating the basic properties of radiation induced defects in ZnS and ZnO and the influence of the atmosphere on the annealing characteristics of the defects. Positron annihilation experiments (both lifetime and Dopplerbroadening measurements) were performed on both single- and polycrystalline samples, irradiated with 3 MeV protons or 1 MeV electrons. For ZnS it was found that both electron and proton irradiation caused significant changes in the positron annihilation characteristics. The annealing of proton irradiated ZnS in air leads to significant oxidation and eventual transformation into ZnO.
Elevated Temperature Implantation of GaAs With Si Ions
Authors: Bhown R. A. , Williams J. S.
Published: April 2011

Abstbact

The formation of amnorphous layers in GaAs during ion bombardment at elevated temperatures, where dynamic annealing of radiation-induced defects is substantial, is shown to be extremely sensitive to the ion flux. fluence. and implantation temperature. For example. with increasing fluence. damage can first build up extremely slowly. then suddenly collapse to the amorphous phase. Alternatively. for a constant ion fluence, a change in flux by one order of magnitude can change the critical temperature for amorphisation by 27°C. and at constant flux and fluence. a change of only 6°C can alter the residual damage from small clusters barely visible by conventional transmission electron microscopy and Rutherlord backscattering to a thick amorphous layer. The temperature at which this occurs is strongly dependent upon the ion flux and fluence.
Interaction of Cavities and Dislocations in Semiconductors
Authors: Follstaedt D. M. , Myers S. M. , Lee S. R. , Reno J. L. , Dawson R. L. , Han J.
Published: April 2011

Transmission electron microscopy of He-implanted Si-Ge and InGaAs shows an attractive interaction between cavities and dislocations. Calculation indicates that cavities are attracted to dislocations through surrounding strain fields, and strong binding (100s of eV) occurs when a cavity intersects the core. In a strained SiGe/Si heterostructure, He implantation enhances relaxation rates, and cavities bound to misfit dislocations show evidence of increasing relaxation at equilibrium by lowering dislocation energies. The interaction is expected for all crystalline solids, and gives insight into voids in GaN/sapphire and bubbles in He-implanted metals.
Growth of Ge1−xCx, Alloys on Si by Combined Low-Energy Ion Beam and Molecular Beam Epitaxy Method
Authors: Shibata H. , Kimura S. , Fons P. , Yamada A. , Makita Y. , Obara A. , Kobayashi N. , Takahashi H. , Katsumata H. , Tanabe J. , Uekusa S.
Published: April 2011

A combined ion beam and molecular beam epitaxy (CIBMBE) method was applied for the deposition of a Ge1−x, Cx, alloy on Si(100) using a low-energy ( 50 – 100 eV ) C+ ion beam and a Ge molecular beam. Metastable Ge1−xCx solid solutions were formed up to x= 0.047, and the CIBMBE method was shown to have a very high potential to grow metastable Ge1−xCx alloys. It was also revealed that the sticking coefficient of C+ ions into Ge was ˜28% for Ei = 100 eV and ˜18% for Ei. = 50 eV. Structural characterization suggests that the deposited films are single crystals grown epitaxially on the substrate with twins on {111} planes. Characterization of lattice dynamics using Raman spectroscopy suggested that the deposited layers have a small amount of ion irradiation damage.
Effects of the Surface on Displacement Cascades Produced by Heavy-Ion Irradiation of Ni3Al and Cu3Au
Authors: Müller S. , Jenkins M. L. , Abromeit C. , Wollenberger H.
Published: April 2011

Stereo transmission electron microscopy has been used to characterise the distribution in depth of disordered zones and associated dislocation loops in the ordered alloys Ni3Al and Cu3Au after heavy ion irradiation, most extensively for Ni3Al irradiated with 50 keV Ta+ ions at a temperature of 573 K. The Cu3Au specimen was irradiated with 50 keV Ni+ ions at an incident angle of 45° at a temperature of 373 K. In Ni3Al the defect yield, i.e. the probability for a disordered zone to contain a loop was found to be strongly dependent on the depth of the zone in the foil, varying from about 0.7 for near-surface zones to about 0.2 in the bulk. The sizes and shapes of disordered zones were only weakly dependent on depth, except for a small population of zones very near the surface which were strongly elongated parallel to the incident ion beam. In Cu3Au the surface had a smaller but still significant effect on the defect yield. The dependence of the tranverse disordered zone diameter d on ion energy E for Ta+ irradiation of NiA was found to follow a relationship d = k1, E1/α with k, = 2.4 ± 0.4 and α = 3.3 ± 0.4. A similar relationship with the same value of α is valid for a wide variety of incident ion/target combinations found in the literature.
Surface Topography of Thin Au and Pd Films After Ion Bombardment Studied With STM
Authors: Reimann K. P. , Rehmet A. , Bolse W. , Geyer U.
Published: April 2011

The changes in surface topography of thin metallic films during ion bombardment were investigated with STM. Pd and Au thin films, having defect-free, atomically flat areas over at least 300×300Å2 were bombarded with Ar+, Kr+, Xe+ ions. Ion energies and target temperatures were varied. The roughening after high fluence irradiation shows scaling with a roughness exponent 0.84. For 300 K target temperature we observe, both for Au and Pd, 3 D erosion, for 700 K, on the contrary, layer-by-layer erosion. The differences in erosion morphologies between Au and Pd surfaces are supposed to stem from differences in surface mobility of adatoms.
Molecular Dynamics Simulation of Cascade Damage in Gold
Authors: Alonso E. , Caturla M. J. , Tang M. , Huang H. , Rubia T. Diaz de ia
Published: April 2011

High-energy cascades have been simulated in gold using molecular dynamics with a modified embedded atom method potential. The results show that both vacancy and interstitial clusters form with high probability as a result of intracascade processes. The formation of clusters has been interpreted in terms of the high pressures generated in the core of the cascade during the early stages. We provide evidence that correlation between interstitial and vacancy clustering exists.