bluuebunny/crossref_metadata_2025 huggingface dataset:
Magneto-Transport Measurements on Si/Si1−xGex Resonant Tunneling Structures
Authors: Gennser Ulf , Kesan V. P , Syphers D. A. , Smith T. P. , Iyer S. S , Yang E. S.
Published: March 2011

We have investigated magneto-transport properties of differently strained Si/ Si1−xGex resonant tunneling devices. The built-in strain was either put in the Si layers, by means of a thick., relaxed Si1−xGex buffer layer, or in the Si1−xGex layers, in which case all Si1−xGex layers were grown below the critical thickness, and a Si1−xGex spacer layer with graded Ge content was used. Magnetic fields parallel to the interface have been employed to probe the in-plane dispersion in the quantum well. This is used to study the effect of band-mixing in the two strain configurations. A field perpendicular to the interface resolves some Landau level splitting. Most strikingly, however, is the similarity in the spectra with the case when the magnetic field is applied parallel to the interfaces. This indicates broadening of the levels, possibly due to scattering, and the importance of 3-dimensional band structure effects.
Substrate Engineering with Fluoride Buffer Layers on Si
Authors: Taylor A. P. , Li W. , Xiao Q.-F. , Schowalter L. J.
Published: March 2011

Here, we report on our efforts to engineer Si substrates for growth of compound semiconductors through the use of suitable epitaxial buffer layers of CaF2, SrF2, and BaF2 using a recently installed dual growth chamber MBE system. We have also developed new graphite-heater K-cells which have demonstrated reliable, high temperature deposition of the fluorides with excellent uniformity across substrates up to 6 inches in diameter. Excellent epitaxial quality (Xmin<5.0%) and smooth surface morphologies have been achieved for epitaxial CaF2 and SrF2 grown directly on Si (111) and BaF2 grown directly on Si (001). The BaF2 is (111) oriented on the Si (001) substrates with one of the {110} planes of the BaF2 aligned with the (110) plane in the Si (001). PbS1−xSex of excellent epitaxial quality has recently been demonstrated on the BaF2 (111)/Si (001) films. Comparable epitaxial quality has been demonstrated for CaF2 grown on Si (001) substrates using a two step growth method. We also report on preliminary results on epitaxial mixed fluoride growth on Si (111) and Si (001) substrates.
The “Computer-Aided Epitaxy” Si:MBE-Control System
Authors: Kubiak R. A. , Newstead S. M. , Powell A. R. , Bowen D. K. , Barlow R. D. , Dowsett M. G. , Whall T. E. , Parker E. H. C.
Published: March 2011

A dedicated, grower-friendly MBE computer control system is described, and its performance in demonstrated in growth of high resolution doped SiGe structures.
Selective Growth of Heteroepitaxial GexSi1−x/Si Lateral Wells Using Pulsed Laser Induced Epitaxy
Authors: Chang Yih , Kramer J. , Chou S. Y. , Sigmon T. W. , Marshall A. F.
Published: March 2011

Patterned GexSi1−x/Si wells are fabricated for the first time by pulsed laser induced epitaxy technique, employing two different semiconductor processing steps to grow these structures selectively. Two different dimensions of Gt0.12 Si0.55 /Si wells are sucessfully formed, in which one is 3.5 μm wide and 1700Å deep while another is 6 μm wide and 1300Å deep. Transmission electron microscopy combined with energy-dispersive X-ray imaging reveals that the 2-D Ge redistribution profiles are well defined and no significant line or surface defects observed. The 2-D Ge well redistribution behavior, governed by heat and mass transport during laser processing, are also discussed.
The Effect of Line Geometry on Void Growth in Thin, Narrow Aluminum Lines
Authors: Børgesen P. , Lee J. K. , Korhonen M. A. , Li C.-Y.
Published: March 2011

The stress induced growth of individual voids in passivated Al-lines at room temperature was monitored in-situ, without removing the passivation. The kinetics was strongly influenced by variations in line geometry, even over distances of many μm, indicating variations in the stress relaxation as well.
Numerical Analysis of the Ball Forming Process in Copper Ball Bonding
Authors: Hongyuan Fang , Yiyu Qian , Yihong Jiang
Published: March 2011

In this paper, the forming process of copper wire ball in copper ball bonding has been studied by numerical analysis. By means of calculation of temperature field, speed field and displacement field for ultrafine copper wire under a miniarc, the regular pattern of copper wire ball formation has been clarified. In this paper, the calculating result of displacement field has also been tested and verified.
Automatic Determination of In-Depth Profiles of Recombination Lifetime in Epitaxial Si Layer with P+-N−-N+ Stripe Test Pattern Diodes
Authors: Usami Akira , Fujii Yoshimaro , Fujiwara Hideki , Sone Tomiyasu , Wada Takao
Published: March 2011

Recombination lifetime of a epitaxial layer (epilayer) is automatically measured by using the conductivity modulation technique. A lateral p+-n−-n+ diode test structure on the surface of the epilayer is formed to evaluate the minority carrier lifetime. Depth profiles of the recombination lifetime are obtained from current-voltage curves of a lateral p+-n−-n+ diode and a vertical n+-n−-n+ structure between the substrate and the top surface. We measure the lifetime in epilayers with and without a buffer-layer. In addition, photo-response of photodiodes with and without the buffer-layer is measured. Profiles of the recombination lifetime depend on the thickness of the epilayer but not on the thickness of the buffer-layer. Minority carrier lifetime in the epilayer, and the leakage current and the photo-response of photodiodes are improved by the buffer-layer formation between epilayer and substrate.
Characterization of Failure Mechanisms and Failure Rate of Oxide Wearout by Hot Electron Using D.C. and A.C. Substrate Electron Injection
Authors: Nishida Toshikazu , Thompson Scott E. , Kavalieros Jack T.
Published: March 2011

Determination of the failure mechanisms and failure rate of oxide wearout by hot carrier injection in submicron metal-oxide-semiconductor field-effect-transistor (MOSFET) requires special test structures to isolate the oxide field dependence of oxide trap generation and charging. A bipolar-MOS transistor (BiMOS) structure is used which d.c. injects substrate electrons into the gate oxide of a MOS transistor by forward biasing the emitter-base n+/p junction of a vertical n+/p/n-inversion-layer bipolar junction transistor. The field and temperature dependences enable a separation of thermal and tunnel electron detrapping rates at low and high oxide field from the generation rate of new oxide traps at high fields. Pulsed a.c. substrate electron injection in a n+ sourced metal-oxide-semiconductor capacitor (SMOSC) structure is used to characterize the field dependence of oxide degradation in chlorinated oxides.
Basic Concepts in Electromigration
Authors: Sorbello Richard S.
Published: March 2011

A review of basic concepts in electromigration is presented and recent theoretical developments are discussed. The microscopic origin of the driving force for electromigration is elucidated and, as an example, the driving force exerted on an impurity near a grain boundary is calculated in a jellium model. A connection is made between the calculated electromigration driving force and 1/f-noise measurements. Results of the first computer simulations of electromigration at the microscopic level are presented. It is found that dynamical recoil effects can lead to a significant enhancement of electromigration for light interstitial impurities.
Mechanical Stress and Electromigration Failure
Authors: Lloyd J. R.
Published: March 2011

The role of mechanical stress in electromigration failure morphology and time to failure is discussed theoretically. It is seen that a tensile stress can accelerate failure significantly and that accelerations from test conditions are also a function of applied stress.
Electromigration Characteristics Under High Frequency Pulsed Current Stressing
Authors: Kwok Thomas , Kaufman R. , Davari B.
Published: March 2011

Electromigration characteristics of Al lines under pulsed current stressing at frequencies 50–200 MHz were measured. Lifetime was found to depend explicitly on both current on-time and current off period. Lifetime increases with t-off as t50 ∝ (t-off)2.2 and decreases with t-on as t50 ∝ (t-on)−0.7. The data indicate no threshold frequency for drastic change in lifetime. Lifetime was also found to increase with duty cycle as t50 ∝ r−2.7, which is a remarkable improvement over an average current density model.
Electromigration in Al/W and Al(Cu)/W Interconnect Structures
Authors: Hu C-K. , Ho P. S. , Small M. B. , Kelleher K.
Published: March 2011

The electromigration drift velocity of Al in Al(3wt.% Si), Al(2wt.%Cu), and Al(2wt.%Cu,3wt.%Si) was measured in a temperature range 133 to 220 °C with current densities of 1.0 to 1.5×106A/cm2. In Al(3wt.% Si), a significant Al depletion at the cathode end and accumulation at the anode end of stripe were observed within a few hours at 1.5×106A/cm2 and 200°C. In addition, local hillocks and voids along the metal lines were observed. For Al(Cu,Si), the Al drift velocity was slowed down by Cu addition. The majority of hillocks started to grow at a distance about 6 μm away from the cathode end with current density of 1.5×106 A/cm2. The drift velocity of Al in Al(Cu,Si) was found to be a function of time starting with an initial low value and increasing to a an final steady-state value. The behavior was attributed to the migration of Cu and dissolution of Al2Cu precipitates. The activation energies of the depletion 3 Aμm of Al(2%,Cu, 3%Si) was determined to be 0.90±02 eV. The dissolution and growth of A12Cu in the tested samples of Ti/Al(2%Cu)/Ti/TiN were observed using the scanning electron microscope and an electron microprobe.
Mechanical Characterization of Photoresist Polymer Coatings as a Function of Processing History
Authors: Tong Kun , Taylor Jeffery F. , Farris Richard J.
Published: March 2011

Photoresist polymer coatings in the film-substratum systems usually generate selfinduced residual stress during processing. It is believed that the residual stress is the driving force for buckling, cracking and delamination of the polymer coatings. Analysis of the residual stress development during processing is of great interest and practical importance.

Holographic interferometry technique has been developed for the direct measurements of general 2-dimensional stresses in thin films.[l] It turns out that it is a powerful technique to analyze residual stress development in polymer coatings during processing. By directly measuring the residual stress for each processing stage, the history of residual stress evolution can be closely followed and the residual stresses generated from different origins can be separated. By varying UV curing dosage, thermal curing temperature and the sequence of thermal and UV curing procedures, different residual stresses from various processing conditions can be comprehensively analyzed. Combining these data with mechanical properties of the coating offers valuable information for better understanding of the processing mechanism and enables one to optimize processing conditions for the best product capability.
The Interplay of Thermo-Mechanical Properties in the Growth and Processing of III-V Materials
Authors: Jordan A. S. , Swaminathan V.
Published: March 2011

The thermo-mechanical properties of III-V semiconductors, in general, and of GaAs and InP in particular, are reviewed. They play an important role in many aspects of semiconductor device fabrication starting from the growth of bulk crystals. Dislocation generation in GaAs and InP are discussed with the emphasis on the theoretical and experimental aspects of reducing the dislocation density in these materials. Such mechanical properties as glide systems, critical resolved shear stress and impurity hardening are covered. The effects of dislocations on device performance are illustrated with examples from photonic and electronic devices. Finally, the effect of thermomechanical stresses in the degradation and reliability of GaAs/AlGaAs and InP/InGaAsP based opto-electronic devices is considered.
Presence of Anelastic Strains in High Lead Solders at Ambient and High Temperatures
Authors: Tien J.K. , Attarwala A.I.
Published: March 2011

We had reported last year that cyclically tested Pb/Sn solders of different compositions exhibited a complicating anelastic effect. The storage and recovery of anelastic strains suppresses damaging creep strain from being stored thus causing non-conservative life prediction estimates and results in complications with respect to accelerated testing. These complications were at that time believed to be characteristic of only eutectic solders at near ambient temperatures. We now find that said complications exist for high end Pb solders and at higher temperatures. Strain rate behavior of high lead solders indicate that a different failure mechanism might exist at temperatures where the material exists as a two phase and in regimes where it exists as a solid solution. Experiments conducted to determine the effect of grain size on accelerated cycling indicated that recrystallization of large grains occurs due to cycling at high temperatures. At ambient temperature, which is greater than half the absolute melting temperature of 90/10 Pb/Sn, it was observed that large grains suppress creep.
Stress Dependent Electrical Activation of Implanted Si IN GaAs - A Four Point Bending Study
Authors: Huang J. G. , Jaccodine R. J. , Huang J. H. , Schwarz S. A. , Schwartz C. L. , Bhat R.
Published: March 2011

A four point bending experiment was conducted to study the effect of stress on the electrical activation of implanted 29Si in GaAs. The stress distribution in the SiNx-coated GaAs was quantitatively examined. 29Si electrical activation was found to depend strongly on the magnitude of the stress when specimens were annealed under tensile stress; compressive stress had a negligible effect. The n-type GaAs was converted into p-type under excess tensile stress. This stress dependence of electrical activation is attributed to the differences in dislocation characteristics and its interaction with implanted Si under tensile or compressive bending.
A Nonlinear and Time Dependent Finite Element Analysis of Solder Joints in Surface Mounted Components Under Thermal Cycling
Authors: Pao Yi-Hsin , Chen Kuan-Luen , Kuo An-Yu
Published: March 2011

A nonlinear and time dependent finite element analysis was performed on two surface mounted electronic devices subjected to thermal cycling. Constitutive equations accounting for both plasticity and creep for 37Pb/63Sn and 90Pb/10Sn solders were assumed and implemented in a finite element program ABAQUS with the aid of a user subroutine. The FE results of 37Pb/63Sn solder joints were in reasonably good agreement with the experimental data by Hall [19]. In the case of 9OPb/1OSn solder in a multilayered transistor stack, the FE results showed the existence of strong peel stress near the free edge of the joint, in addition to the anticipated shear stress. The effect of such peel stress on the crack initiation and growth as a result of thermal cycling was discussed, together with the singular behavior of both shear and peel stresses near the free edge.
Control of Microstructure and Stress in Sputtered Tungsten Thin Films on Silicon
Authors: Kola R.R. , Celler G.K.
Published: March 2011

Tungsten is attractive for VLSI device metallization because of its high conductivity and resistance to interdiffusion and electromigration. It is also one of the best absorber metals for x-ray lithographic masks. To minimize distortions in an x-ray mask, intrinsic stresses in the absorber films have to be low and reproducible. The physical properties of thin films are very dependent on their microstructure. We present the results of a study of the microstructural evolution and the resulting internal stress of rf sputter-deposited W films as a function of rf power, deposition temperature, and argon pressure. By controlling the nucleating phase and mobility of the adatoms, we have produced W films with low stresses (<±50 MPa). The lattice parameter and the argon content in W films increased with decreasing argon deposition pressure. It was found that a low base pressure (<10−7 torr) is necessary to produce stable α-phase W and to eliminate the metastable β-phase. Stresses in the W films were not affected bysubsequent anneals in vacuum at 200 °C for 50 hrs. In-situ stress measurements indicated stress relaxation by plastic deformation above 300 °C.
Selective Growth of Poly-Diamond Thin Films Using Selective Damaging by Ultrasonic Agitation on a Variety of Substrates
Authors: Ramesham R. , Roppel T. , Ellis C.
Published: March 2011

Polycrystalline diamond thin films have been selectively deposited on Si, SiO2, Si3 N4, Ta, Mo, alumina, and sapphire substrates using selective damaging by ultrasonic agitation. Novel processes were developed to selectively damage the polished substrates by ultrasonic agitation. Optical and scanning electron microscopy is used to study selectivity and morphology of as-grown diamond thin films.
Mechanical Behavior of Materials in Microelectronic and Fiber-Optic Structures: Application of Analytical Modeling - Review
Authors: Suhir E.
Published: March 2011

The overwhelming majority of studies in microelectronics and fiber-optics are experimental. Not too many apply numerical, mainly finite-element, methods to analyze microelectronic and fiberoptic structures. There is a very small number of papers using analytical modeling. At the same time application of powerful and well-developed analytical methods of Engineering Mechanics often enables one to obtain valuable prior information of the mechanical behavior of materials and structures, interpret empirical data, and to extrapolate the accumulated experience on new designs [1,2]. As a rule, application of analytical modeling results in better understanding of the behavior and performance of a material or structure, and in substantial savings of time and expense. This review, based primarily on the author's research, addresses several basic and practically important problems related to the mechanical behavior of materials and-rational structural design of microelectronic and fiber-optic systems and lending themselves to sufficiently simple analytical solutions.
Continuous Wetiability Measurement for Solder Reflow
Authors: Melton Cynthia M. , Yarling Susan M. , Raleigh Carl J.
Published: March 2011

A quantitative dynamic solder wettability mesurement technique was utilized to evaluate the effects of reflow processing on the wettability parameters associated with solder ball alloys. This technique enables the examination of the final degree of solder wetting and the continuous monitoring of wetting as a function of time during the reflow process under nitrogen atmosphere. An experimental design approach employing a 24 full factorial experiment was formulated to illustrate the use of this measurement technique investigating the final result of wetting. Solder wettability was determined with respect to the contact angle, base diameter and height of the reflowed solder ball alloy. The most significant effect estimates with respect to contact angle were solder flux and pad metallization. Solder ball alloy was found to significantly impact the base diameter and height of the reflowed solder. The effect of solder flux activators and pad metallizations on the subsequent continuous solder wettability wetting rates and amount of molten solder spread of solder ball alloys during reflow were measured. Reflow with a relatively more activated solder flux material was found to enhance the rate of solder wetting of the the pad metallization.
Numerical Simulation & Experimental Investigation of SMT Laser Microsoldering Thermal Process
Authors: Chunqing Wang , Yiyu Qian , Yihong Jiang
Published: March 2011

In this paper,a numerical simulation of thermal process in the SMT laser microsoldering joint has been developed, in which, the influence on thermal process of the factors such as the thermal conductivity variation of solder with temperature, light reflection coefficient of the lead wire surface, and heat exchange on the surface of SMT materials all have been considered. In order to carry this numerical calculation practice and prove it's results,the reflexive characteristic of light wave to the SMT materials has been gauged,and the dynamic temperature process of laser microjoint has been measured by a new experimental method which was invented by the authors.

The results of numerical simulation have been borne out by the tests, and the influences of heating parameters on thermal process has been analysed in this paper.The conclusions will be advantageous to the further study of the microjoint quality control in the SMT laser microsoldering.
Mechanisms of Inelastic Deformation and Stress Relaxation in Thin Metallizations Bonded to Hard Substrates
Authors: Korhonen M.A. , Bergesen P. , Li Che-Yu
Published: March 2011

The yield strength of metallic thin films bonded to hard substrates can be significantly higher than is customary for bulk samples of the same metal. This is related to the constrained nature of the deformation. The constrained deformation, as well as the commonly observed crystallographic texture of thin films, places restrictive conditions on the mechanisms of deformation that produce stress relaxation. In narrow aluminum based metallizations used as interconnects in large scale integrated circuits thermal stress induced voiding provides an effective means for stress relaxation. For these interconnects, the stress state is tensile after excursions to higher temperatures; the stresses relax mainly by dislocation glide and grain boundary sliding during the cooldown, while the longer term relaxation is governed by stress-induced voiding and dislocation creep.
Properties Of A Photoimageable Thin Polyimide Film II.
Authors: Maw Taishih , Hopla Richard E.
Published: March 2011

The polylmide synthesized from benzophenonetetracarboxylic dianhydride and alkyl-substituted diamines is inherently photosensitive at ≤365 nm, and a solvent soluble, negative-acting system can be formulated from the fully-imidized resin. The lithographic, thermal, mechanical, and electrical properties of the polyimide films have been characterized. This polyimide film shows good thermal, mechanical, and electrical properties, and a 1:1 aspect ratio is consistently achieved on 10 μm thick films. The thermal properties of the films were determined using TGA and TMA methods. The decomposition temperature was 527°C, the weight loss of the cured film at 350°C in nitrogen was 0.04 %/hour and the thermal expansion coefficient was 37 ppm/°C. The dielectric constant and dissipation factor of the film were 3.0 and 0.003 respectively at 4% humidity. The effects of hard-bake time, hard-bake temperature, nitrogen purge rate during heat treatment, and humidity on the thermal and electrical properties of the thin film were also examined, and are presented here. The rate of weight loss of the cured film increases when the rate of nitrogen purge decreases or when the cure temperature increases. Longer heat treatments resulted in a slight decrease in the CTE and an Increase in the Tg. The electrical properties of the films are dependent both on the humidity during measurement and on the hard-bake temperature.
Electrical Properties Of Thin Polyimide Films Prepared By Ionized Cluster Beam Deposition
Authors: Jung Hyung-Jin , Lee Dong-Heon , Lee Jeon-Kook , Whang Chung-Nam
Published: March 2011

The electrical properties of gold – polyimide - silicon structures were investigated experimentally by capacitance – voltage (C – V) measurement. Polyimide films were deposited on silicon substrate by using ionized cluster beam deposition (ICBD) of PMDA-ODA followed by in-situ thermal curing in N2 atmosphere. The resulting C – V plots show hysteresis, and it was believed to be due to the injection of carriers. The interface trap density is fairly low because of the clean interface provided by ICB technique.
Organo-Soluble, Segmented Rigid-Rod Polyimides: Synthesis and Properties
Authors: Harris F. W. , Hsu S. L. C. , Lee C. J. , Lee B. S. , Arnold F. , Cheng S. Z. D.
Published: March 2011

Several segmented, rigid-rod polyimides have been prepared that are soluble in organic solvents in their fully imidized form. The polymers were prepared from commercial dianhydrides and 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl (TFMB). Their intrinsic viscosities ranged from 1.0 to 4.9 dL/g. Tough, colorless films could be cast from m-cresol solutions at 100°C. The polymers had glass transition temperatures (Tgs) above 275°C and displayed outstanding thermal and thermo-oxidative stability. Fibers were prepared from the 3,3′,4,4′-tetracarboxybiphenyl dianhydride (BPDA) based polymers that had moduli of 130 GPa and tensile strengths of 3.2 GPa. The thermal expansion coefficients and dielectric constants of thin films (20–25 μm) of the polymers were as low as −2.40×10−6 and 2.5, respectively.
Polyimide Copolymers Containing Various Levels Of The 6F Moiety For High Temperature And Microelectronic Applications
Authors: Haider M. , Chenevey E. , Vora R. H. , Cooper W. , Glick M. , Jaffe M.
Published: March 2011

Trifluoromethyl group-containing polyimides not only show extraordinary electrical properties, but they also exhibit excellent long-term thermo-oxidative stability. Among the most thermomechanically stable structural polyimides are those from 6F dianhydride (6FDA) and 6F diamines. The effects of substituting non-fluorine containing monomers such as BTDA, mPDA and 4,4′-DADPS for the hexafluoroisopropylidene monomers on the dielectric, thermo-oxidative, thermal and mechanical properties of the copolymers were studied.
Poly(Enaminonitriles): Novel Materials For Use In Microelectronics
Authors: Moore J. A. , Kim Ji-Heung
Published: March 2011

A series of new poly(enaminonitriles) were synthesized by the condensation polymerization of three different bis(chlorodicyano-vinyl) aromatic monomers with various aromatic diamines. These polymers have moderate to high molecular weight with intrinsic viscosities ranging from 0.35 to 0.77 dl/g and form flexible films. These polymers exhibit good solubility in many organic solvents and excellent thermal stability, retaining their weight up to 400 °C in air. Poly(enaminonitriles) undergo ‘curing’ reactions at high temperature (˜300 °C) to provide insoluble, infusible material without emission of volatile by-products. Dielectric constants of these polymers ranged from 3.5 to 5.2 depending on the structure. Their thermal and dielectric properties are correlated to the structures.
Preparation Of Polyimide-Silica Hybrid Films
Authors: Kakimoto Masa-aki , Morikawa Atsushi , Iyoku Yoshitake , Imai Yoshio
Published: March 2011

Polyimide-silica hybrid films were successfully prepared by the sol-gel reaction starting from a mixture of tetraethoxysilane (TEOS), a solution ofpolyamic acid in N, N-dimethylacetamide and water of pH 7 and pH 3. The hybrid films were obtained by the hydrolysis-polycondensation of TEOS in the polyamic acid solution, followed by heating at 270°C. Fairly flexible films were obtained for silica contents up to 70 wt%. The films containing less than 8 wt% of silica were yellow and transparent, whereas the films with higher silica contents were yellow and opaque. The density of the silica in the hybrid films was estimated to be 1.65 and 1.69 g/cm3 (pH 7 and pH 3). The29Si nuclear magnetic resonance spectrum indicated that the silica in the films consisted of non-hydroxy, monohydroxy, and dihydroxy siloxane structures. Silica particles with submicron diameter were observed in the hybrid films containing less than 8 wt% silica, whereas larger particle size around 5 μ m in the case of higher silica content. The decomposition temperature of the hybrid films increased with increasing silica content. The glass transition temperature of the hybrid films showed the minimum at 8 wt% of silica content. Tensile properties, such as elongation at break, tensile strength, and tensile modulus also exhibited the same tendency. The linear thermal expansion coefficient of the silica in the hybrid films was estimated to be 1.3 × 10−5 and 0.3 × 10−5 (pH 7 and pH 3), which suggested that the silica had a porous structure.
Vertical-Cavity Surface-Emitting Lasers: Mbe Growth and Optical
Information Processing Applications
Authors: Harbison J. P. , Florez L. T. , Scherer A. , Chang-Hasnain C. J. , Lehmen A. C. Von , Chan W. K. , Clausen E. M. , Orenstein M. , Jewell J. L
Published: March 2011

The basic issues involved in the growth by molecular beam epitaxy (MBE) of
vertical-cavity surface-emitting lasers (VCSELs) are discussed. Successful
VCSEL optical information processing applications demonstrated to date are
discussed, including two-dimensional arrays, holographic memory retrieval,
optical addressing, wavelength division multiplexing, and tunable VCSEL
operation.
Quantum-Well Lasers for High-Speed Optical Information
Processing
Authors: Wu M. C. , Chen Y. K. , Tanbun-Ek T. , Logan R. A.
Published: March 2011

Monolithic colliding pulse mode-locked (CPM) multiple quantum well lasers
generating optical pulses as short as 600 femtoseconds are reported. The CPM
laser is built on a single chip of InGaAs/InGaAsP multiple quantum well
laser. The pulse repetition rates are synchronized with an rf synthesizer up
to 40 GHz in hybrid mode-locking scheme. In passive mode-locking scheme, a
record high repetition rate of 350 GHz has been achieved. All the
sub-picosecond pulses obtained have pulse shapes of sech2 and
transform-limited timebandwidth products between 0.30 to 0.34. This new
optical source is very useful for ultra-high speed optical switching and
optical logic in optical fibers, and ultra-long distance optical soliton
transmissions.
AlGaAs/GaAs Double-Heterostructure Optical Waveguide on Si
Substrates
Authors: Yuasa T. , Umeno M. , Sakai S. , Wada N. , Ueta Y.
Published: March 2011

AlGaAs/GaAs double-heterostructure (DH) optical waveguides on Si substrates
which is important in future opto-electric integrated circuits (OEICs)
utilizing both Si and GaAs devices is analyzed by the effective index method
and fabricated by metalorganic chemical vapor deposition (MOCVD).

The structures contain 0.8-μm-thick GaAs guiding layer sandwiched between
two 1-μm-thick Al0.1Ga0.9 As cladding layers. All the
layers were grown by MOCVD on (100) 2°-off Si substrates by two step method.
A top cladding layer was etched leaving 2-μm wide mesa-stripes. The etched
depth was changed from 0.65 to 0.90 μm. The field profiles were calculated
and measured for 1.3 μm wavelength light. The measured and calculated
profiles agree quite well with each other for all the. waveguides having
different mesa height. This agreement makes us possible to design more
complicated AlGaAs/GaAs waveguides and modulators on Si substrates.
Possibility of a Si-Based Infrared Detector Using
Microcrystalline B-Si-Ge Alloys
Authors: Osaka Y. , KOhno K. , Shresta P.
Published: March 2011

Microcrystalline films of B-Si-Ge alloy have been deposited by the
sputtering of Ge target in atmosphere of SiH4 and
B2H6. Microcrystalline B-Si-Ge alloy/Si
hetero-junction was fabricated on p-type Si(100) wafers with the resistivity
of 1∼10 Ωcm. The barrier height of this Schottky structure was estimated to
be in the range of 0.20∼0.30 eV which can be controlled by inclusion amounts
of boron. The reverse biased Schottky characteristic using the
microcrystalline B-Si-Ge alloy as to the gate shows the avalanche breakdown
by illuminating of 6 μm light.
The Problem of Doping Wide Gap II-VI Compound Semiconductors and
Its Solutions
Authors: Wang W. I.
Published: March 2011

Wide gap II-VI compound semiconductors are difficult to be doped
amphoterically. After more than thirty years of research in II-VI compound
semiconductors, there does not even exist a satisfatory simultaneous
explanation as to why ZnSe can be easily doped n-type while undoped ZnTe
only exhibits p-type conductivity. In this paper we propose an explanation
based on the III-V/II-VI analogy which for the first time can explain these
phenomena, and provide solutions to the problem of doping II-VI compound
semiconductors.
Optical Interconnection Network Co-Integration: The Potential of
Optical Polymers
Authors: Hornak L. A. , Weidman T. W.
Published: March 2011

The explosive growth under way in the performance of digital electronic
systems is directly traceable to the impact of Si MOS device scaling and its
accompanying increase in functionality at the chip level. The increasing
data rates and chip I/O that have accompanied this scaling have driven the
evolution of both system architectures and the interconnection and packaging
technologies (i.e. chip carriers, printed circuit boards, bus structures)
that support this CMOS functionality and dominate overall system volume. The
further scaling of CMOS technology towards 0.1 – 2.5μm
minimum gate lengths coupled with modest increases in chip size (i.e. 2–4
cm), promise upwards of a 100 fold increase in chip-level complexity. The
resulting emergence of Ultra Large Scale Integrated (ULSI) processor array
chips and wafer-scale memory (solid state disks) hold the potential for
extremely compact distributed computing systems. Through a continuation of
the evolutionary trends of system scaling, application of chip level process
technology to higher system levels, and mixed technology integration (e.g.
BiCMOS); present advanced packaging technologies based upon Multi-Chip
Modules (MCM) will mature into hybrid wafer-level three-dimensional silicon
systems allowing burdensome driver and communication control functions now
designed at the chip level to move off chip into the active silicon
interconnection substrate where network transmission and control can both be
implemented. Realization of the performance potential of these silicon ULSI
systems will largely depend on the successful implementation of this
wafer-level communication network linking the high-density of processing
nodes. The role that any advanced technology (i.e. high-speed normal
electronic, superconducting, optical) will serve within this network will be
determined by the degree of connectivity it can achieve in this scaled
environment and by its ability to benignly coexist with the dominant CMOS
technology, the network's physical and functional foundation[l].
Photo-Polymerized Acrylic Waveguides for Optical
Interconnects
Authors: Krchnavek Robert R. , Lalk Gail R. , Denton Robert
Published: March 2011

We have fabricated acrylic based optical channel waveguides using proximity
photolithography as well as laser direct writing. The cladding layer is a
photosensitive aliphatic urethane dimethacrylate and the guiding layer is a
photosensitive aromatic acrylated epoxy. This material system provides good
adhesion to a variety of substrate materials. Since both the guiding and
cladding layers are applied, these materials can be employed in several
electrical/optical applications including multi-chip modules using Si,
SiO2, and polyimide as well as high speed electronic board
technologies using teflon based substrates.

Loss measurements show a guide loss of less than 0.08 dB/cm for multi-mode
waveguides fabricated using the direct write laser technique.
Lithographically defined guides have a loss of 0.3 dB/cm for similar size
waveguides.
An Atomistic Study of the Equilibrium Segregation of Hydrogen to Tilt Boundaries in Nickel
Authors: Moody N. R. , Foiles S. M.
Published: March 2011

In this study, Monte Carlo simulations have been combined with Embedded Atom Method (EAM) calculations to study hydrogen segregation at the atomic level in an ideal nickel lattice with a Σ9 tilt boundary. The calculations indicate that trap binding energies exceed 0.5 eV on the tilt boundary, but decrease rapidly with distance. Furthermore, the calculations show that trap site occupancy increases with trap site binding energy and hydrogen activity, and reach saturation at high hydrogen concentrations. Most importantly, significant rearrangements in tilt boundary structure are predicted to occur as hydrogen concentration increases. The results are consistent with observations that show significant hydrogen concentration enhancement at grain boundaries in nickel and palladium. They also parallel the effect of hydrogen concentration on crack growth susceptibility in nickel and iron-rich alloys. However, the change in boundary structure as hydrogen concentration increases challenges our understanding of hydrogen-induced fracture.
Interface Structure and Slip Transmission in TI-49AL-3NB
Authors: Schwartz Daniel S. , Sastry S. M. L.
Published: March 2011

Two types of special grain boundaries were examined in Ti-49Al-3Nb deformed at elevated temperatures. The first can be described as a Σ=2 order-changing boundary. This boundary is faceted and results from the nucleation and growth of variants of the γ phase from the parent α phase. The second type of grain boundary is a γ/α2 interphase boundary, and transmission of slip through this type of boundary was examined. Slip transmission from γ into α2 did not produce distinct slip bands in α2,. Slip transmission from γ through α2, and into the next γ lamella was possible even when the next γ lamella was in an orientation rotated relative to the first γ lamella.
Thermal Desorption of Hg Monolayers from Cu(100)
Authors: Kime Y. J. , Zhang Jiandi , Dowben P. A.
Published: March 2011

A two dimensional phase transition from one adlayer structure to another is an inherent part of the thermal desorption of one monolayer of Hg on Cu(100). The energetics of this phase transition have been studied using thermal desorption spectroscopy (TDS). The TDS spectra reflect the coexistence of the two structural phases for a range of Hg exposures. The TDS spectra have been analyzed within a Polanyi-Wigner framework modified to account for the phase transition.
Grain Boundary Sliding Kinetics and Stress Relaxation Phenomena in Ni Alloys
Authors: Cosandey F. , Ui S. , Cao B. , Schaller R. , Benoit W.
Published: March 2011

Internal friction measurements have been performed on Ni-20 wt% Cr alloys containing trace additions of Ce ranging from 0 to 180 at ppm, in order to determine grain boundary sliding kinetics and associated stress relaxation phenomena. Two anelastic relaxation peaks have been observed corresponding to intrinsic grain boundary sliding between carbide precipitates and to macroscopic sliding with elastic accommodation at triple points. The effects of Ce on these grain boundary phenomena and resulting alloy ductilities are also presented.
Quantitative X-Ray Structure Determination of Superlattices and Interfaces
Authors: Schuller Ivan K. , Fullerton Eric E. , Vanderstraeten H. , Bruynseraede Y.
Published: March 2011

We present a general procedure for quantitative structural refinement of superlattice structures. To analyze a wide range of superlattices, we have derived a general kinematical diffraction formula that includes random, continuous and discrete fluctuations from the average structure. By implementing a non-linear fitting algorithm to fit the entire x-ray diffraction profile, refined parameters that describe the average superlattice structure, and deviations from this average are obtained. The structural refinement procedure is applied to a crystalline/crystalline Mo/Ni superlattices and crystalline/amorphous Pb/Ge superlattices. Roughness introduced artificially during growth in Mo/Ni superlattices is shown to be accurately reproduced by the refinement.
Time-Resolved Si Lattic-Temperature Measurement on Wide Time Scale (10−9–100 sec.) During Laser Annealing
Authors: Murakami Kouichi , Itoh Hisayoshi , Tohmiya Yoshinori , Takita Kōoki , Masuda Kohzoh
Published: March 2011

Time-resolved Si lattice-temperature measurement has been developed on wide time scale from 10−9 to 100 sec during laser annealing, by utilizing the time-dependent optical interference in Si on sappire. This interference is due to small changes in Si refractive index induced by temporal changes in Si lattice-temperature. For ns–pulsed laser annealing, part of the absorbed photon energy is found to be transferred into lattice (phonons) in a time much shorter than 40-ns pulse duration. A new method using a microscope is demonstrated for time- and space-resolved Si latticetemperature measurements during cw laser annealing.
Reflectivity of Silicon-on-Sapphire During Pulsed Laser Annealing
Authors: Chen Y. H. , Lyon S. A.
Published: March 2011

Using a visible probe laser (632.8 nm) we have directly observed motion of the melt front in silicon-on-sapphire during pulsed laser annealing. The average penetration and regrowth velocities have been determined to be 13 and 6.5 m/sec. respectively. These values are in agreement with recent conductivity measurements and heat flow calculations. In addition, the data demonstrate that the high-reflectivity phase can penetrate at least .5 um (Si thickness) and requires a significant amount of the time to do so. These results are further evidence that the high–reflectivity phase is molten silicon.
Optical Response of Electron-Hole Plasma in Surface Excited Semiconductors
Authors: Forchel A. , Schweizer H. , Laurich B. , Tränkle G. , Mahler G.
Published: March 2011

A unified approach is presented which reconciles contradictory results obtained in earlier studies of optical spectra of inhomogeneous electronic systems in semiconductors: A consistent analysis of the optical data implies strong deviations from quasi-equilibrium in the carrier distributions. The non-equilibrium nature of the plasma is confirmed by a Mott-transition based study of the plasma transport.
Semiconductor Processing with Excimer Lasers: An Overview
Authors: Young R. T.
Published: March 2011

The present level of development of excimer lasers, as it relates to semiconductor processing, and the advantages of these lasers for such processing, are reviewed. Extensive comparisons of the quality of annealing of ion-implanted Si obtained with XeCl and ruby lasers are presented. Major applications in the area of solar cell fabrication, siliconon-sapphire technology, laser photochemical processing, and submicron optical lithography are outlined and discussed.
Multiple Layer Sputter Deposition and Laser Annealing of Silicon Films
Authors: Anderson W. W. , Mac Millan H. F. , Katzeff J. S. , Lopez M.
Published: March 2011

The formation of single crystal multiple layers on silicon substrates with thicknesses in excess of 1 μm has been demonstrated to be a viable process. Film build-up is via repetitions of the steps (1) pre-deposition chemical cleaning of wafer, (2) magnetron sputter deposition of 0.3 pm thick amorphous Si, (3) interfacial mixing via 190 keV implantation of Si, and (4) film epitaxial crystallization via pulsed laser annealing. Doping has been demonstrated by both (1) P ion implantation and (2) P incorporation from PH3; included in the sputter gas ambient.
Applications of Energy Beams in Material and Device Processing
Authors: Galvin G.J. , Hung L.S. , Mayer J.W. , Nastasi M.
Published: March 2011

Energetic ion beams used outside the traditional role of ion implantation are considered for semiconductor applications involving interface modification for self-aligned silicide contacts, composition modification for formation of buried oxide layers in Si on insulator structures and reduced disorder in high energy ion beam annealing for buried collectors in transistor fabrication. In metals, aside from their use in modification of the composition of near surface regions, energetic ion beams are being investigated for structural modification in crystalline to amorphous transitions. Pulsed beams of photons and electrons are used as directed energy sources in rapid solidification. Here, we consider the role of temperature gradients and impurities in epitaxial growth of silicon.
Large Area Continuous Electron Beam for Semiconductor Processing
Authors: Moore Cameron A. , Rocca J. J. , Collins G. J. , Russell P. E. , Geller J.
Published: March 2011

We have achieved wide area (38 cm2) electron beam heating of semiconductor materials using a glow discharge electron beam with electron energies between 3 and 7 keV. A continuous beam 7 cm in diameter with a power density up to 90 W/cm2 was used to anneal both boron-implanted (30 keV, 5 × 1015 atoms/cm2) n-type <100> silicon wafers as well as two types of Ti-Si composite films to form this titanium disilicide Annealing of the implanted samples was obtained without redistribution of the original dopant profile using a 15-sec. electron beam exposure. Formation of TiSi2 was found to decrease the sheet resistivity of these samples a factor of ten for both 400 Å films of Ti on Si and codeposited Ti-Si mixtures of overall stoichiometry TiSi2. Due to the high electron beam power density achieved over a large area, one can uniformly anneal an entire wafer in a single exposure without sample or beam scanning.
The Effects of Thermal and Transient Annealing on the Redistribution of Indium Implanted Silicon
Authors: Katz W. , Smith G.A. , Reihl R.F. , Koch E.F.
Published: March 2011

The redistribution of indium in silicon has been studied as a function of dose during rapid thermal annealing. The results show little redistribution of indium for doses 1×1015 cm−2. For a 350keV/5×1015 cm−2 indium implant, the annealed sample showed significant indium precipitation and near surface defects. These data are contrasted to an earlier study of a 300keV/1×1015 cm−2 indium implanted silicon sample that was furnace annealed for 30 minutes at 1050°C. The furance annealed sample showed redistribution to both implant damage and the amorphous crystalline interface as well as a tail on the backside of the implant due to interstitial diffusion. This interstitial tail is clearly minimized in the transient annealed sample.
Germanium Implantation into Silicon: An Alternate Pre-Amorphization/Rapid Thermal Annealing Procedure for Shallow Junction Technology
Authors: Sadana D.K. , Myers E. , Liu J. , Finstad T. , Rozgonyi G.A.
Published: March 2011

Germanium implantation into Si was conducted to pre-amorphize the-si surface layer prior to a shallow/high dose (42 keV, 2 × 1015 cm−2) BF2 implant. Cross-sectional transmission electron microscopy showed that rapid thermal annealing (RTA) of the amorphous layer (without BF2 ) leaves defect-free material in the implanted region. Only a discrete layer of small (∼300Å) dislocation loops due to straggling ion damage was found to be present at a depth corresponding to the amorphous/crystalline interface. RTA of the amorphous layer with the BF2 creatpd a high density of uniformly. distributed fine defect clusters (∼50Å) in the surface region (0–500Å) in addition to the straggling ion damage. Boron and F profiles obtained by secondary ion mass spectrometry from the unannealed and rapid thermally annealed samples showed the presence of high concentrations of these impurities in the surface region where the fine defect clusters were observed. A comparison of the RTA behavior of the pre-amorphized surface layers (with or without BF2 ) produced by Ge and self-implantation is presented.
Effects of Heating Samples on the Extended Defect Generation During Pulsed Electron Beam Annealing of Silicon
Authors: Pitaval M. , Ambri M. , Tholomier M. , Barbier D. , Chemisky G. , Laugier A.
Published: March 2011

A non destructive SEM observation method has been applied to investigate the extended defects created by pulsed electron beam annealing of arsenic–implanted silicon. The defect study was performed on bevelled samples after irradiation using variable beam fluences for both a 20°C or a 450°C specimen starting temperature. Dislocation generation resulting in subgrain boundaries formation occurs during regrowth of the silicon layer which has been heated up to the melt point or higher. For the rather penetrating electron beam pulse used in this work the subgrain size and their depth extent depend on the beam fluence and the substrate temperature. For 450°C pre‐heated samples, annealing of the arsenic implant is possible without any stable extended defect creation using the 1.0 – 1.2 J.cm−2 fluence range.