bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laser Assisted E-Beam Epitaxial Growth of Si/Ge Alloys on Si
Authors: Martin Smith Paul , Lombardo S. , Uttormark M.J. , Cook Stephen J. , Thompson Michael O. 
Published: March 2011

ABSTRACTA novel laser-assisted technique for e-beam epitaxial growth of GexSi1−x alloys on <100> Si has been investigated. During deposition, a XeCl excimer laser is used to either heat, or to melt and crystallize, the GexSi1−x continuously as the material is evaporated. This process of heating or melting and crystallizing can be continued until the desired film thickness is achieved. At incident laser energy densities which produce melt, the underlying crystalline seed ensures epitaxial growth during the subsequent solidification. Depositions of films up to 3 at.% Ge under this liquid regime, with substrates held nominally at room temperature, exhibited complete epitaxial growth. At energy densities below the melt threshold, enhanced surface mobility for epitaxial alignment is required. Depositions in this regime exhibit only partial epitaxial growth with conversion to fine grained polycrystalline growth after short distances.
A New Approach to Grow Strain-Free GaAs on Si
Authors: Sohn Hyunchul , Weber Eicke R. , Tu Jay , Wang Shyh 
Published: March 2011

ABSTRACTThe major problems of the GaAs/Si heteroepitaxy are the high density of threading dislocations and the high residual strain in the GaAs epilayers. The residual strain in the epilayer is attributed to the difference in contraction during cooling down from the growth temperature. It was reported previously that the residual stress in GaAs epilayer could be reduced by reducing the growth area using substrate patterning. In this paper, we report a new approach to grow strain- free GaAs layer on Si substrates. The residual strain in GaAs/Si is tensile in nature, therefore we attempted to compensate this thermally induced strain by compressive lattice mismatched strain. The thermally induced strain in the GaAs layer was successfully compensated by the lattice- mismatch induced strain using In0.032Ga0.968As. By that method, we could grow thin strain- free GaAs layers on Si without patterning. The strain relieving effect was confirmed by photoluminescence experiment.
An in Situ Hrem Study of Crystal Nucleation in Amorphous Silicon thin Films
Authors: Kirtikar A. S. , Morgiel J. , Sinclair R. , Wu I-W. , Chiang A. 
Published: March 2011

ABSTRACTIn Situ high resolution electron microscopy has proved to be a valuable tool in investigations involving interface reactions in a number of thin film systems. We have applied this technique to dynamically record nucleation and growth sequences during the amorphous (a-) to crystalline (c-) phase transformation in silicon thin films. Interpretation of the recordings has yielded a wealth of information on the mechanisms and to some extent the kinetics of solid phase crystallization. In our recordings, we have been able to capture the critical nucleus at the a-Si-SiO2 interface. Incorporating this into classical nucleation theory enables us to make an estimate of the a-Si-c-Si interfacial energy.
Initial Formation of SiGe/Si Epitaxial Structures And Oxides Produced By Wet Oxidation Of Amorphous SixGe1−x Layers.
Authors: Prokes S. M. , Rai A. K. 
Published: March 2011

ABSTRACTEpitaxial SiGe/Si heterostructures have been formed by wet oxidation from amorphous SixGe1−x, films deposited on Si(100). This process does not occur by solid phase epitaxy(SPE) due to the presence of a contamination layer between the film and the substrate. The model which has been suggested involves both the diffusion of Si to the forming oxide and enhanced Ge diffusion below this contamination layer. The oxide which is formed in this process consists of four separate layers, with the middle two containing both SiO2 and GeO2. In addition, initial epitaxial formation appears to occur in random regions, probably where the diffusing Si breaks through the contamination layer. Epitaxial submicron “donut” regions on Si(100) can also be formed by this method, and the mechanism will be discussed.
The Effect of Heat Treatments on the Microstructure and Electrical Properties of A1/Tiw/Polycrystalline Si Contacts
Authors: Berger S. , Komem Y. , Weiss B. Z. 
Published: March 2011

ABSTRACTThe effect of heat treatments on the microstrueture, composition and electrical properties of the Al/TiW/ Polycrystal1ine Si system was studied systematically for the first time. It was found that Al and Si diffuse through the grain boundaries of the TiW layer at 400°C. Subsequently, Si accumulates at the Al/TiW interface while Al diffuses into the po1ycrystal1ine Si. TiSi, TiSi2, Al3Ti, and WAl10 are formed only at the Al/TiW interface as a result of the heat-treatments for 30min at temperatures between 450 and 500°C. The sheet resistance, measured on the surface of the Al film, is constant up to 350°C and then increases with the heat treatment temperature at all times. The I–V curves are characteristic to Schottky diodes. The general dependece of the current on the applied voltage remains the same but the electrical resistance changes as a result of the heat-treatments. At the long annealing time(30min), the electrical resistance decreases with the heat-treatment temperature. However, at the short annealing times(10–60sec), it first incrsases(between 400 and 450°C) and then decreases (between 450 and 500°C). The results of the electrical measurements are correlated to the microstructural and compositional changes occured due to the heat treatments.
Thin Film Reactions on Alloy Semiconductor Substrates
Authors: Olson D. A. , Yu K. M. , Washburn J. , Sands T. 
Published: March 2011

ABSTRACTThe interactions between Pt thin films and In53Ga47As have been studied. An important result is that the reaction kinetics deviate from those of other metal/compound semiconductor reactions. The kinetics can be divided into two stages, where the reaction slows by a factor of 5 after ~60 minutes of annealing at 400°C. In addition, Auger depth-profiling indicates that an In-rich layer develops at the reacted layer/substrate interface.
Coarsening of Ga2Se3 Islands on GaAs Substrates
Authors: Palmer J.E. , Zembutsu S. , Tohno S. , Katsui A. 
Published: March 2011

ABSTRACTThe formation and growth of islands on GaAs substrates has been observed during high temperature (550°C) heat treatment of GaAs substrates in the presence of H2Se. We have used SEM, TEM and XPS to characterize these islands and we have proposed a mechanism for island formation based on coarsening of Ga on the substrate surface followed by reaction with H2Se to form Ga2Se3.
Evidence for a Grain Boundary Grooving Model of Agglomeration in Polycrystalline Tisi2 Thin Films
Authors: Nolan Thomas , Beyers Robert , Sinclair Robert 
Published: March 2011

ABSTRACTAn equilibrium model for agglomeration based upon the mechanism of grain boundary grooving in polycrystalline thin films is suggested. It involves an energy balance between surface, interface, and grain boundary energies, and predicts parameters which will influence the onset of agglomeration. It has been determined that small grain size, low grain boundary energy, high film surface and interface energies, and growth of single crystal epitaxial layers should promote resistance to agglomeration. Polycrystalline TiSi2 thin films deposited on Si substrates have been observed using cross-section TEM. The micrographs provide evidence that, for these films, the grain boundary grooving mechanism is dominant and most of the modeling assumptions are valid.
Nist Program on Measurements of the Properties of Materials in Electronic Packaging
Authors: Carpenter Joseph A. 
Published: March 2011

ABSTRACTReduction in the feature sizes of electronic chips is forcing a commensurate decrease inthe sizes of the various structures in packaging so that the assumption that the materials of the structures have bulk properties is suspect, especially near the interfaces. Historically, packaging has not received research and development as sophisticated as thatof the chip, so a collection of techniques specific to packaging technology has not beendeveloped. The National Institute of Standards and Technology (NIST) has identified the need for and initiated efforts to develop and refine such techniques. This paper will discuss the current NIST program and plans which were developed in conjunction with industry and other government agencies. Initial attention is given to measurements of the electrical, thermal, mechanical, and chemical properties of all types of materials used in the packaging.
Experimental Determination of the Two-Dimensional State of Stress and the Orthotropic Elasticity Coefficients for Coatings
Authors: Farris Richard J. , Maden M. A. , Tong K. 
Published: March 2011

ABSTRACTThe state of stress for a uniform coating away from the edges reduces to that of plane stress, two in-plane normal stresses, and an in-plane shear stress. For this state, the interface between the coating and the substrate is totally stress free. Since the substrate and the coating are not interacting mechanically, an internal section of the substrate can be removed creating a tensioned drum-like membrane without altering the stress state. Holographic interferometry of vibrationally excited membranes is used to evaluate the stress. Using this technique, up to thirty vibrational modes can be obtained. This high degree of redundancy enables one to determine the one shear and two normal stresses that act in the plane of the coating. The only physical property requires is the coating density. The density is obtained from commonly reported literature values. Simple variations on the membrane vibration scheme, e.g., cutting the membrane to create a uniaxially tensioned ribbon, enables one to determine the in-plane Poisson's ratio and shearmodulus.In separate but related experiments on commercially made free-standing films with residual orientation, the above techniques, combined with special free and axially constrainedcompressibility experiments should enable all of the Poisson's ratios and elasticmoduli for an orthotropic material (nine elastic constants) to be determined. Methods for measuring the state of stress and the elastic constants are required to predict the state of stress in complex coating geometries.
Hardness and Adhesion Measurements of Copper Metallizations by a Continuous Indentation Approach
Authors: Lafontaine W.R. , Li Che-Yu 
Published: March 2011

ABSTRACTA continuous indentation test has been used to evaluate the difference in adhesion between copper films deposited on oxidized silicon substrates with different transition metalinterlayers. Variations in adhesion between samples with interlayers of Al,Cr,Ni,Ti and V correlated with the free energy of formation of the particular metal oxide present.
Mechanical Reliability of Film/Substrate Systems Intended for Electronic Packaging
Authors: Chouaf A. , Ignat M. , Norrnandon Ph. , Terriez J.M. 
Published: March 2011

ABSTRACTCalculations of thermoelastic internal stresses for different systems comprised of one or several films deposited on a substrate are presented. The calculated stresses are compared to stresses directly determined by deflection measurements. The film(s)/substrate systems were submitted to cyclic bending tests in order to analyse the evolution of their internal stresses. When a significant relaxation of the stresses is detected, it is discussed with respect to the activation of irreversible deformation mechanisms, which will depend on the nature of the phases constituting the system.
Metallization Behavior in Aluminum Nitride Electronic Packages
Authors: Luh Ellice Y. , Dolhert Leonard E. , Enloe Jack H. , Lau John W. 
Published: March 2011

ABSTRACTCharacteristics such as CTE close to that of silicon, high thermal conductivity, and good dielectric properties make aluminum nitride (AIN) an excellent dielectric for packaging silicon-based high density multichip interconnects. However, there remains many aspects of its behavior that have not been characterized. One such example is the behavior of the various metallizations used within a package. As with A12O3, these metallizations must contribute toward a hermetic seal separating the die from the environment. However, the chemical behavior of the metallization systems used for A12O3 may not be compatible with non-oxide ceramics such as AIN. Consequently, these chemical interactions are investigated in view of the requirements for each application within electronic packages. Hermeticity testing results are also included in the discussion.
A Novel Photosensitive Polyimide
Authors: Hirano Takashi , Sashida Nobuyuki , Takeda Toshiro , Tokoh Akira 
Published: March 2011

ABSTRACTWe developed a novel negative photosensitive polyimide composition for microelectronics. It was prepared by the synthesis of polyamic acid precursor in N, N-dimethly acryl amide. The solution properties, processing conditions and film properties are compared with two conventional, ester and ion type photosensitive polyimides.The novel composition has higher sensitivity than the other two types because the density of the photoreactive groups is much higher. And it provides wider patterning process range, better adhesion and lower final curing temperature.We also examined the effect between three types of polyimides and epoxy molding compounds on the reliability of ICs after moisture/solder reflow process. The novel photosensitive composition has good adhesion to metals, inoranic layers and molding compound and improves the reliability of ICs by supressing the interfacial delamination.
Diffusion and Adhesion of Cu/Parylene
Authors: Yang G. , Dabral S. , You L. , Bakhrut H. , McDonald J. F. , Lu T.-M. 
Published: March 2011

ABSTRACTThe combination of Cu and parylene (poly-p-xylylene) for metallization and insulator in integrated circuit or packaging multilayer interconnection systems gives one of the lowest resistance and capacitance values per unit length. In this paper we present a detailed study of the diffusion characteristics of Cu in parylene-n (PA-n) substrates. PA-n was vapor-deposited and Cu metallization performed at room temperature using the Partially Ionized Beam (PIB) technique. Rutherford Backscattering (RBS) technique has been used to study the diffusion of Cu in PA-n substrate after annealing the samples to elevated temperatures in vacuum. We found no sign of Cu diffusion after the Cu/PA-n sample was annealed at 300°C for 6 hours. Diffusion occurs at 350 °C. However, preannealed PA-n substrate prior to Cu deposition can prevent the diffusion even at a temperatures above 350°C. Also we found that amorphous carbon and chromium are good diffusion barriers of Cu on PA-n. The dry adhesion between PA-n deposited on Al, Cu and Ag was found to be good. The adhesion of these PIB deposited metals on PA-n in high vacuum was also very good.
Moisture Uptake of Bisbenzocyclobutene (BCB) Films for Electronic Packaging Applications
Authors: Pranjoto Hartono , Denton Denice D. 
Published: March 2011

ABSTRACTElectronic packaging has been changing.rapidly to meet the often conflicting demands of higher speed and lower cost. In the multichip module (MCM), an array of semiconductor chips is mounted on a substrate and interconnected via a network of multilevel metal lines with polymer layers used as a dielectric between orthogonal metal signal paths. A potential reliability problem that must be investigated is the absorption of moisture by the dielectric in the MCM package. Moisture absorption may lead to long term problems such as loss of adhesion, corrosion of the metal interconnect and increased insulator conductivity.Bisbenzocyclobutene (BCB) is an insulating polymer that is being used in the MCM package as a dielectric material. In this work, the moisture uptake in BCB is investigated gravimetrically using a Cahn-1000 microbalance with a resolution of I pgram. The BCB films are spincoated onto silicon substrates and cured yielding film thickness ranging from 7 to 20µm. The moisture uptake of the BCB film is monitored in situ and non destructively to reveal the performance of the film as used in an integrated circuit environment. The moisture uptake of the films was monitored at different ambient relative humidity (RIH) values between 20% and 80% at 23°C. The transient behavior of the moisture absorption in BCB films has been characterized. Moisture uptake in BCB films increases as the relative humidity is increased, and reaches a maximum of less than 0.2% by weight at 80% RH. By comparison, this moisture uptake is significantly lower than that of fully cured PMDA-ODA polyimide, which is about 2.5% by weight under similar conditions. The transient data show that the equilibration time for a 22.8 µ.m film is approximately 220 seconds, yielding a diffusion coefficient of about 4.5µm2/s.
Phase Formation in Cr/Co/Au and Cr/Co/Au/Pb(Sn) Multilayered Structures
Authors: Moske Michael A. , Ho Paul S. , Nering Alexander T. , Agarwala Birendra N. 
Published: March 2011

ABSTRACTThin-film reaction with solder and its influence on stress have been investigated in Cr/Co/Au and Cr/Co/Au/Pb(Sn) structures. Results from X-ray analysis and RBS measurements reveal that without the Pb(Sn) layer the dominant reaction occurs by interdiffusion of Co and Cr followed by the reaction of Cr and Au. In contrast, the addition of the Pb(Sn) layer leads to a rapid dissolution of Au into Pb, which is followed by subsequent reaction of Co and Sn. In this reaction the intermetallic phases CoSn and CoSn2 are formed. These material reactions are correlated with measurements of the mechanical stresses of the multilayer structure during annealing which were carried out using a bending beam method. The overall reaction scheme of the multilayer structure and the individual reaction kinetics are discussed.
Copper Film Deposition by Hydrogen Atom Reactions with Copper Compounds
Authors: Li Hongwen , Reeves Robert R. 
Published: March 2011

ABSTRACTA novel low temperature CVD process - atom reaction CVD process for metal film depositions has been developed by using hydrogen atoms reacting with metal compounds. High purity copper films, with low resistivity of ∼ 2 μΩ cm, good step coverage to submicron holes and good adhesion to various substrates, were obtained by using this process with Cu(HFA)2 source at substrate temperatures below 150 °C.
Customized Circuit Interconnect and Repair by Laser Seeding and Constriction-Induced Plating.
Authors: Partridge Julian P. , Chen C. Julian 
Published: March 2011

ABSTRACTA novel method has been developed for producing customized copper interconnections on thermally-sensitive substrates by laser seeding followed by constrictioninduced electroplating. A polyimide, polytetrafluoroethylene, or glass-epoxy substrate is first sprayed with palladium acetate solution. 500 nm thick palladium interconnects are then formed using a 514 nm argon ion laser (10 mW - 50 mW) to selectively pyrolyze the acetate film. After cleaning, the part is immersed in an acid copper electrolyte and an alternating current (0.1 Amp - 2.0 Amp) passed through the palladium seed. Joule heating produces a cathodic shift in the equilibrium potential (dε0/dT = 0.63 mV/degree) which causes electrodeposition of copper along the seeded connection.Cross-sectional microscopy and electrochemical polarization studies show that local plating current densities of 10 mA/cm2 produce 1000 εm × 25 εm × 10 εm line geometries exhibiting excellent mechanical and electrical properties. The large process window suggests that customization and repair on lincwidths below 1 mil (25 εm) should be achievable routinely.
Mechanical Characteristics of In and Pb5Sn Solders in a Thinfilm Multichip Package
Authors: Darveaux Robert , Yung Edward , Turlik Iwona , Murty K.L. 
Published: March 2011

ABSTRACTThe mechanical properties of the solder joints, in a thin film multichip module, were evaluated using constant deformation-rate, creep and load-relaxation tests in shear mode on specially fabricated samples which are representative of the multichip configuration. While majority of the testing was performed at ambient temperature, a limited amount of study was made to characterize the temperature dependence of the deformation characteristics. Constitutive equations were developed for predicting the deformation behaviors of the solder joints under varied test conditions as well as the in-service reliability of these joints.
Subcritical Crack Growth at a Polymer/Glass Interface
Authors: Ritter J.E. , Conley K. , Steul D. , Lardner T.J. 
Published: March 2011

ABSTRACTSubcritical crack growth at polymer/glass interfaces can occur due to a stress dependent chemical reaction at the crack tip at a crack driving force less than the critical fracture energy for catastrophic crack propagation. A four—point flexure apparatus coupled with an inverted microscope allows observation in situ of the subcritical crack growth at the polymer/glass interface. The specimen consists of soda—lime glass plates bonded together with epoxy acrylate. In the four—point flexure test, the strain energy release rate is independent of the interfacial crack length. This test technique allows for subcritical crack growth at the polymer/glass interface to be measured as a function of the applied crack driving force and relative humidity. The results are discussed in terms of a fracture mechanics model.
Selective Growth of GaAs and A1xGa1−xas by Omvpe Using Tertiarybutylarsine
Authors: Tokuda K. L. , Kisker D. W. , Lamont-Schnoes M. , Lopata J. 
Published: March 2011

ABSTRACTWe have investigated the use of tertiarybutylarsine (TBAs) to selectively grow GaAs and AlxGa1−x As in trenches on partially-masked GaAs substrates. Both SiyNz and Si02 masks have been used, with geometries ranging from 4 - 160 μm. By varying temperature and pressure, we have optimized selectivity and minimized “ridge” growth near masked areas. The results show TBAs may be a suitable alternative to arsine for selective regrowth of these materials.
Gas Phase Decomposition of an Organometallic Chemical Vapor Deposition Precursor to Ain: [A1(CH3)2NH2]3
Authors: Amato Carmela C. , Hudson John B. , Interrante Leonard V. 
Published: March 2011

ABSTRACTA CVD reactor has been coupled to a molecular beam apparatus in order to study the gas phase decomposition of an organometallic precursor to AIN, tris-dimethylaluminum amide, [(CH3)2AINH2]3. The onset of decomposition occurs at a reactor temperature of 125°C. By 300°C, all mass spectral signals due to precursor have disappeared. With the addition of helium as a carrier gas in the CVD process, the temperature at which all precursor signals disappear is raised to 400°C. The evolution of methane accompanies the precursor decomposition. Mass spectra of the precursor and its deuterated analogue, [(CH3)2 AIND2]3, obtained between 50°C and 90°C, offer support for the existence of trimer-dimer-monomer equilibria in this temperature range.
Decomposition and Impurity Analysis of Organotellurium Precursors for MOVPE
Authors: Hails J.E. , Girling I.R. , Stern D.R. 
Published: March 2011

ABSTRACTThis paper discusses the application of gas chromatography-mass spectroscopy (GC-MS) to the assessment of precursors for the MOVPE growth of (Hg,Cd)Te. GC-MS has been used to analyse precursors for volatile organic and organometallic impurities. An extension of the technique has also allowed precursor decomposition reactions and interactions to be studied. Information obtained on alkyl purity, decomposition and interactions has been shown to be of direct relevance to the optimisation of growth.