bluuebunny/crossref_metadata_2025 huggingface dataset:
Grain Growth in Titanium Silicide Films During the Formation Reaction
Authors: Corcoran Yunji L. , King Alexander H. , deLanerolle Nimal , Kim Bonggi , Berg John
Published: March 2011

Titanium films of 0.5 µm thickness were sputter deposited on silicon substrates. After rapid thermal annealing at temperatures ranging from 600°C to 850°C for times up to 45 seconds in nitrogen, transmission electron microscope (TEM) cross section specimens were made from the wafers. Grain sizes of the resulting titanium disilicide were measured from TEM cross section micrographs. The results show that C49-TiSi2 has a different grain growth rate than C54-TiSi2- Under our experimental conditions, C54-TiSi2 has a much higher growth rate. Titanium silicide on arsenic implanted silicon substrates shows a lower grain growth rate than that on unimplanted substrates under the same conditions. The thickness of the silicide layer was also measured for each specimen. The relationship of thickness and grain size will be discussed.
Grain Structure and Growth of Dispersed Phase BN-AlN Coatings Grown via Chemical Vapor Deposition
Authors: Freeman Garth B. , Lee Woo Y. , Lackey W. J. , Hanigofsky John A. , More Karren
Published: March 2011

This paper discusses the variation in microstructures encountered during the separate depositions of boron nitride (BN) and aluminum nitride (A1N) as well as during the codeposition of BNߝA1N dispersed phase ceramic coatings. This combination was chosen in order to take advantage of the self lubricating properties of hexagonal BN along with the hard, erosion resistance of A1N. Films were characterized using scanning and transmission electron microscopy (SEM and TEM), x-ray photoelectron spectroscopy (XPS), and x-ray diffraction (XRD).

A range of coating microstructures are possible depending on the conditions of deposition. The best films produced, in terms of hardness, density, and tenacity, were a fine mixture of turbostratic BN and preferentially oriented A1N whiskers aligned with the whisker axis perpendicular to the substrate surface as seen by both electron microscopy and x-ray diffraction.
Texture Evolution During Grain Growth of Aluminum Films
Authors: Knorr David B. , Tracy Daniel P. , Lu Toh-Ming
Published: March 2011

Aluminum films 1pm in thickness are deposited by sputtering and by partially ionized beam (PIB) deposition. In the as-deposited condition, the sputtered film has a weak texture while the PIB film has a very strong {111} fiber texture. Annealing at temperature between 250°C and 400°C for 0.5 hr induces grain growth accompanied by texture evolution. These aluminum films are characterized by an {111} texture superimposed on a random grain distribution. When the {111} component dominates as in the PIB condition, little texture evolution accompanies grain growth at successively higher temperatures. When the {111} component is weak, the random component decreases at the expense of a strengthening {111}. Grain growth kinetics are similar for both cases.
Effect of Heat Treatment on the Microstructures and Electrical Properties of Insb Thin Films
Authors: Wang P. W. , Yeh S. , Chang L.
Published: March 2011

Polycrystalline InSb thin films have been prepared by two-source thermal evaporation method. The as-deposited randomly oriented thin films develop (111) preferred orientation upon heat treatment of different maximum setting temperatures, T(max)s. Under different T(max)s, the elongate (111) grains rotate gradually the direction of the elongation respect to the thermally oxidized Si(100) substrate.

The (111) preferred orientation has been seen from both cross-sectional TEM and X-ray diffraction patterns. The electrical mobility value of the thin film has been measured by the Van der Pauw′s method. A dramatic increase in the electrical mobility from few thousands, for the as-deposited film, to intermediate values of 15,000-30,000 cm2/v-s and the highest value of 36,000 cm2/v-s for thin films subjected to different T(max)s, can be correlated well to the corresponding microstruetures.
ECR Enhancement of Low Pressure PECVD Diamond Synthesis
Authors: Chang Jan-Jue , Mantei Thomas D. , Vuppuladhadium Rama , Jackson Howard E.
Published: March 2011

Diamond films have been synthesized by microwave Plasma Enhanced CVD (PECVD) and permanent magnet induced Electron Cyclotron Resonance (ECR) PECVD of hydrogen diluted methane. The films are characterized by SEM images and Raman spectroscopy. The diamond films grown by ECR-PECVD show clear-cut habits of cubic crystal in SEM images, while the film grown by microwave PECVD are the polycrystalline. A Raman line at 1333cm‒1 and broad band located at ∼1500 cm‒1 were obtained for the films grown by both methods. However, the film grown by microwave PECVD shows a larger broad band which is associated with an sp2-bonded graphitic phase
Evolution of Stress During Formation of Titanium Disilicide by Rta and Tube Furnace Annealing
Authors: Jongste J.F. , Loopstra O.B. , Janssen G.C.A.M. , Radelaar S.
Published: March 2011

Integrated circuit fabrication consists of many processing steps: e.g. lithography, etching, implantation and metallization. Some of these processes are combined with thermal processing. Heat treatments require special attention because previous fabrication steps may be influenced: e.g. dopant profiles may be deteriorated. The amount of interference of an annealing step with a former process is determined by the ratio of the reaction rates (and hence by the difference in activation energies).
A Bulk Study of Homoepitaxy
Authors: Baxter C. S. , Somekh R. E.
Published: March 2011

We present preliminary results aimed at investigating the effects of variation in temperature on the epitaxial growth of thin films of single elements and multilayers.

In this paper we present results of a cross-sectional electron microscopy study of films in which good epitaxy has been established and then the deposition temperature has been significantly reduced (for example to 30°C from 120°C). The main objective was to study the nature of the low temperature limit of layer by layer epitaxy and the degree of roughening as a function of the deposition conditions with an emphasis on the kinetics of the process.
Material Characterization of Low-Temperature Silicon Epitaxial Growth on Patterned Oxidized Wafers by ULPCVD From SiH4/SiF4/H2
Authors: Yew Tri-Rung , Reif Rafael Reif
Published: March 2011

Low temperature silicon selective epitaxial growth on patterned oxidized wafers is becoming crucial to ultra large scale integration (ULSI) technologies. Low temperature processes can reduce dopant redistribution via solid state diffusion so that a sharp transition region can be obtained. This paper presents material characterization of epitaxial films grown on patterned oxidized wafers by ultralow pressure chemical vapor deposition (ULPCVD) from SiH4/SiF4/H2 (≤ 10 mTorr), in which SiF4 was used to explore its capability for selective epitaxial growth. The deposition temperature is 800°C. The effects of the SiF4 addition to SiH4/H2 are discussed. Defects in epitaxial layers resulting from a high composition of the SiF4 during deposition were characterized. Results of in–situ surface cleaning using a SiF4/H2 plasma are also presented.
Structural and Electrical Effects on (A1-Si)/n+Si Ohmic Contact of in Situ Silicon Cleaning by Ar IONS Bombardment
Authors: Santangelo A. , Lanza P. , Viscuso O. , Magro C. , Scandurra A. , Licciardello A. , Torrisi A.
Published: March 2011

In situ etching of native Si02 by Ar+ ion bombardment before metal sputter deposition can increase the contact resistance of the metal-semiconductor contact. This is commonly attributed to surface contamination produced by various mechanisms or to etch-induced surface damage. In this paper, in order to elucidate the cause of the increase of contact resistance, we have studied (Al-Si)/n+Si contacts prepared by various treatments of the Si surface. We attribute the higher postalloy contact resistance of the sputter etched contacts to the existence of an Al doped layer which formation was induced by the preexisting disordered layer created by the Ar+ ion bombardment.
The Sputter Deposition and Characterisation of High Quality Single Crystal Mo Thin Films
Authors: Somekh R. E. , Van Vechten D. , Blamire M. G. , Tricker D. M. , Barber Z. H. , Glowacka D. , Kroeger R. , Stobbs W. M. , Lovellette M. N. , King S. E. , Evetts J. E.
Published: March 2011

We report on the epitaxial growth of superconducting molybdenum films on sapphire substrates. These films are to be etched into arrays of isolated cylinders, each 1–5μm in diameter. When placed in a magnetic field and biased at 0.95 Tc(H), the flux movement associated with their bolometric response to the energy deposited when radiation is absorbed will provide the basis of a gamma-ray detector.

The films were prepared by UHV sputter deposition at temperatures between 650° and 840°C. Besides standard XRD analysis the films were examined by TEM. An epitaxy orientation relationship with sapphire was found similar to that observed for niobium. Electrical conductivity measurements were made as a function of temperature down to Tc, the superconducting transition temperature, which ranged from below 0.35K to above 0.8K for films with a high room temperature resistance ratio (e.g. 300 in a 0.9pjn thick film). Results from a range of films will be presented and their Tc’s discussed.
Growth Mechanism of Epitaxial Oxide Films by Laser MBE
Authors: Nagata Hirotoshi , Yoshimoto Mamoru , Tsukahara Tadashi , Gonda Satoshi , Koinuma Hideomi
Published: March 2011

Crystallographic structure and valence state of CeO2 and Nd2-O3 films deposited by laser MBE on Si substrates were investigated by reflection high energy electron diffraction (RHEED) and X-ray photoelectron spectroscopy (XPS). In contrast with epitaxial growth of CeO2 (111) and Nd2O3(111) on Si (111), epitaxial films were not obtained on Si(001). Partially reduced mixed valence (4+ and 3+) Ce was indicated to exist by XPS in the cerium oxide film within 2nm from the interface with Si. Beyond this transition layer, two-dimensional growth of CeO2 film on Si(111) was verified from in situ RHEED and as well as on Si(001) from XPS measurements.
Domain Boundaries formed during Epitactical Growth of α-Al2O3
Authors: Bentley J. , Sklad P.S.
Published: March 2011

Domain boundaries have been characterized by transmission electron microscopy in single crystal [0001] α-Al2O3 epitactically regrown after being amorphized by stoichiometric ion implantation. The domains are facetted on {1120} and have dislocation-like features at facet intersections. End-of-range dislocation loops on (0001) appear to be the nucleation site for the domains. Diffraction contrast, high resolution imaging, and convergent beam electron diffraction techniques showed that two types of domains are present which involve cation stacking sequences which are out of phase with the matrix as a result of translation along and/or inversion of [0001]. The non-inverted regions can be described as anti-phase domains, whereas those with [0001] inverted also have a basal twin character.
Maskless Deposition of a Micropattern on a Wafer by Liquid Flow
Authors: Mil’shtein S. , Fournier C.
Published: March 2011

Metalization patterns of micron size were deposited chemically on GaAs wafers with no litography masks by means of controlled laminar flow of liquid NaOCl. Iron used for metalization was dissolved in NaOCl wafer solution. To interrupt the continuous deposition of metal on semiconductor surface, the acrylic polymer was also dissolved in the liquid. Iron deposition appears to follow given crystalographic direction <110> creating a set of parallel lines in <110> direction. Spacing between the lines and width of the metallic lines are controlled by the temperature of the process, speed of liquid flow and percentage of polymer present in the solution.
Asymmetric Relaxation in Epitaxial Layers of III-V Compounds
Authors: Turnbull A. G. , Green G. S. , Tanner B. K. , Halliwell M. A. G.
Published: March 2011

Relaxation in a 3μm epitaxial layer of GaAsSb on GaAs, a 1μm layer of InGaAs on InP and an InGaAs superlattice on InP has been investigated by double crystal X-ray diffractometry and double crystal X-ray synchrotron topography and found to be asymmetric. The origins of assymetric relaxation are discussed and the sensitivity of diffractometry and topography to the detection of layer relaxation compared.
Atomistic Simulation of Formation and Structure of Misfit Dislocations
Authors: Nandedkar A.S. , Murthy C.S. , Srinivasan G.R.
Published: March 2011

In our earlier work [1] we had reported first theoretical observations of the spontaneous formation of 60° and 90° misfit dislocations in Au/Ni (15.9% mismatch) systems for the (111) and (001) interfaces respectively. Here, we present the analysis of the evolution of the dislocation configuration as it evolves from a highly strained coherent Au film. The driving force for the formation of these misfit dislocations was the reduction in the config-urational energy during the iterative relaxation of the atoms. A finely stepped energy minimization technique was developed to relax the high energy configuration. Misfit dislocations were also obtained for low misfit systems (Pd/Ni - 10% and Pd/Cu - 7.76%), but a modified approach, which is described here, was used for these systems which shows an energy barrier to the formation of dislocations in the low misfit systems.
In Situ Tem Studies of The Growth of Strained Si1-xGex By Solid Phase Epitaxy
Authors: Paine D. C. , Howard D. J. , Evans N. D. , Greve D. W. , Racanelli M. , Stoffel N.G.
Published: March 2011

In this paper we report on the epitaxial growth of strained thin film Si1-xGex on Si by solid phase epitaxy. For these solid phase epitaxy experiments, a 180-nm-thick strained-layer of Si1-xGex with xGe=11.6 at. % was epitaxially grown on <001> Si using chemical vapor deposition. The near surface region of the substrate, including the entire Si1-xGex film, was then amorphized to a depth of 380 nm using a two step process of 100 keV, followed by 200 keV, 29Si ion implantation. The epitaxial regrowth of the alloy was studied with in situ TEM heating techniques which enabled an evaluation of the activation energy for strained solid phase epitaxial regrowth. We report that the activation energy for Si1-xGex (x=l 1.6 at. %) strained-layer regrowth is 3.2 eV while that for unstrained regrowth of pure Si is 2.68 eV and that regrowth in the alloy is slower than in pure Si over the temperature range 490 to 600°C.
Lattice Relaxation of Eras/Gaas: An X-Ray Scattering Study
Authors: Miceli P. F. , Moyers K. W. , Palmstrøm C. J.
Published: March 2011

The results of a high resolution x-ray scattering study of [001]ErAs epitaxial layers grown on [001]GaAs is presented. ErAs is pseudomorphic on GaAs for thicknesses below 70Å and, for thicker films, lattice relaxation is oberved concomitant with an Increase of the In-plane mosaic due to the formation of misfit dislocations. Above 300Å, the out-of-plane transverse scattering from the ErAs lattice planes Is no longer specular and further relaxation Is related to the out-of-plane mosaic. The ratio of elastic constants, C12/C11, Is determined to be 0.126 and the thermal expansion was measured. Thin film Interference oscillations are observed and modeled. ErAs/GaAs Is an Ideal system for x-ray scattering studies of lattice relaxation and structure in epitaxial layers. Films as thin as 20Å have been studied.
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

A 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

The 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

In 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

Epitaxial 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

The 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

The 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

The 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

An 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

Reduction 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

The 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

A 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

Calculations 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.
Modification and Reactions of Aluminum Nitride Surfaces
Authors: Norton M. Grant , Yang T.K. Andrew , Kotula Paul , Rugg Kevin L. , McKernan Stuart , Carter C. Barry
Published: March 2011

The durability and oxidation behavior of polycrystalline aluminum nitride substrates have been investigated using scanning electron microscopy and x-ray diffraction.
Metallization Behavior in Aluminum Nitride Electronic Packages
Authors: Luh Ellice Y. , Dolhert Leonard E. , Enloe Jack H. , Lau John W.
Published: March 2011

Characteristics 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

We 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

The 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

Electronic 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

Thin-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

A 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

A 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

The 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

Subcritical 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

We 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

A 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

This 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.
Characteristics of Sulfur in OMVPE Grown Indium Phosphide
Authors: Tyagi S.D. , Ehsani H. , Ghandhi S.K.
Published: March 2011

Doping of indium phosphide, grown by organometallic vapor phase epitaxy (OMVPE), has been carried out using hydrogen sulfide. For low partial pressures of H2S, the carrier concentration in the epitaxial layers is found to increase linearly. However, for higher partial pressures a region of superlinear doping is seen. For still higher partial pressures, a rapid decrease in carrier concentration is seen. In the linear region, the doping has a weak dependence on phosphine pressure, however, peak carrier concentration is higher for lower phosphine pressures.

The layers were studied using Hall Effect and Double Crystal X-Ray Diffraction, in order to elucidate the nature of impurities and compensating centers introduced. A model which explains the above characteristics is proposed for S incorporation in MOVPE grown InP.
Solid Phase Equilibria in the Ni-in-P System.
Authors: Andersson-Söderberg Margaretha
Published: March 2011

The solid phase equilibria in the Ni-In-P system at 800 °C have been determined at ambient pressure using X-ray diffraction supplemented with differential thermal analysis from room temperature to 800 °C. One ternary phase, Ni21In2P6, was found in the system. It crystallizes with space group Fm3m and is isostructural with Cr23C6. Indium phosphide forms equilibria with the nickel phosphides Ni2P, Ni5P4, NiP2 and NiP3 and indium with Ni12P5 and Ni2P. The results are in agreement with previous observations that Ni2P is a stable phase when a nickel thin film deposited on InP is reacted to completion.
Doping Effects on the Etching Chemistry of GaAs and Si
Authors: Houle F. A.
Published: March 2011

Doping effects on semiconductor etching rates have been proposed to be associated with field effects in the near-surface region. Detailed investigations of the chemistry of nand p-type Si and GaAs indicate that the majority carrier can also play an important role in determining the reactivity of surface intermediates, providing an independent mechanism for influencing the etch rate. A microscopic picture of central driving forces in semiconductor etching deduced from the doping cffects is proposed.
Homoepitaxial Growth of Crystalline Ge Films through a Liquid Metal Medium at Low Temperature
Authors: Xiong Fulin , Golovehenko Jene A. , Spaepen Frans
Published: March 2011

Crystalline films of Ge have been homoepitaxially grown through a liquid Au medium by the so-called vapor-liquid-solid (VLS) mechanism at relatively low temperature (400-450 °C). During the process, the Ge vapor is delivered by a molecular beam evaporator and the liquid phase in the system is formed at the interface by heating a Au metal film above its eutectic point with the semiconductor. This process has a potential of a high growth rate at low temperature. The growth process and the crystallinity of the films were monitored in situ by high energy ion backscattering and channeling. The surface morphology and quality of the films were examined by scanning electron microscopy and cross-sectional transmission electron microscopy. The experimental results are presented, together with a discussion of the growth mechanism and the nature of the liquid metal-semiconductor interface.
Surface Reaction Mechanisms in Chemical Beam Epitaxy
Authors: Foord John S. , Singh Nagindar K. , Wee Andrew T.S. , French Cathy L. , Fitzgerald Emma T.
Published: March 2011

Surface reaction mechanisms which underly the growth of III-V semiconductors by chemical beam epitaxy have been investigated using a combination of surface spectroscopic techniques in conjunction with modulated molecular beam scattering techniques. Emphasis is placed on understanding the complex growth rate effects observed during the growth of Ga(Al,In)As and the origin of selected area epitaxy. These effects are shown to arise from the surface sensitive nature of the decomposition of the group III alkyl source chemicals used in CBE.
Adsorption and Decomposition of Diethylsilane on Silicon Surfaces
Authors: Coon P.A. , Wise M.L. , Dillon A.C. , Robinson M.B. , George S.M.
Published: March 2011

Diethylsilane (DES), Si(C2H5)2H2, is a promising candidate for the atomic layer epitaxy of silicon. The adsorption and decomposition kinetics of DES on silicon surfaces were studied using laser-induced thermal desorption (LITD), temperature programmed desorption (TPD), and Fourier transform infrared (FTIR) spectroscopy. FTIR studies on porous silicon surfaces indicated that DES dissociatively adsorbs below 600 K and produces Si-H and Si-C2H5 surface species. The desorption products following DES adsorption on Si(111) 7×7 were C2H4 and H2 for all surface coverages using both LITD and TPD techniques. Ethylene and H2 desorption occurred at 700 and 810 K, respectively, during TPD experiments with a heating rate of β = 9 K/s. Ethylene desorption was consistent with a β-hydrogen elimination mechanism from the Si-C2H2 surface species. Isothermal LITD studies monitored the desorption kinetics of C2 H4 from Sl (111) 7×7 as a function of time following DES exposures. The first-order ethylene desorption kinetics were Ed = 36 kcal/mol and vd = 2.7 × 109 s−1. Additional LITD measurements determined that le initial reactive sticking coefficient of DES on Si(111) 7×7 decreased versus surface temperature. The temperature-dependent sticking coefficients suggested a precursormediated adsorption mechanism.
A Molecular Beam Study of the Reaction of Molecular Chlorine with Gallium Arsenide
Authors: Su Chaochin , Dai Zi-Guo , Lee Gang Ho , Vernon Matt
Published: March 2011

Molecular chlorine is scattered from a GaAs(100) surface and the reaction products detected by a mass spectrometer. A careful analysis of the velocity and angular distributions of the reaction products as well as the vibrational energy dependence of the daughter ion fragmentation pattern shows that the steady state reaction is stoichiometric in the removal of Ga and As until the incongruent evaporation rate exceeds the etch rate induced by the incident chlorine flux. The depletion of the nonreactive molecular chlorine signal is accounted for by the flux of chlorinated reaction products. The absolute etch rates as well as the incident chlorine flux are determined from the known evaporation rate of GaAs at the incongruent evaporation temperature. Modulated molecular beam scattering is used to establish some necessary reaction steps.
Comparison of H2 Desorption Kinetics from Si(111)7×7 and Si(100)2×l
Authors: Wise M. L. , Koehler B. G. , Gupta P. , Coon P. A. , George S. M.
Published: March 2011

The desorption kinetics of hydrogen from the β1 H2 -TPD state on Si(111)7×7 and Si(100)2×l were studied using laser-induced thermal desorption (LITD) and temperature programmed desorption (TPD) techniques. Isothermal LITD studies of H2 desorption from Si(111)7×7 revealed second-order kinetics with a desorption activation energy of Ed = 62 ±4 kcal/mol and a preexponential factor of Vd = 92 ±10 cm2 /s. In contrast, H2 desorption from Si(100)2×l revealed first-order kinetics with an activation energy of Ed = 58 ±2 kcal/mol and a preexponential factor of Vd = 5.5 ±0.5 × 1015 s−1. The desorption kinetics yield similar upper limits for the Si-H bond energies but different desorption mechanisms on Si(lll)7×7 and Si(100)2×l.
Apid Thermal Oxidation of Silicon: Aspects of the Initial Regime Kinetics
Authors: Messaoud A. Yahia , Martinez A. , Sarrabayrouse G. , Scheid E.
Published: March 2011

The kinetics of silicon oxidation by rapid thermal processing in the 1000-1200°C range have been studied with particular attention paid to the homogenization and optimization of the heating and to the initial conditions (i.e. sample preparation, insertion into the furnace and measurements of initial thickness ). Special emphasis has also been placed on the accuracy of thickness measurements using ellipsometry and adequate calculations. Comparison of the experimental and simulated thickhnesses using Han and Helms' model and comparative temperature evaluation, allowed the real temperature to be evaluated within ±5°C. Then, it was concluded that RTO kinetics does not reveal any special peculiarities in the 2-35 nm range.

Electrical measurements of RTO capacitors (C-V, I-V, V-t) have been performed. Typically, a breakdown electrical field strength (Eox) of 15 MV/cm, a Nss max of 3.1011 eV−l.cm−2, a Nss midgap of 4.1010 eV−1.cm−2 and a Qbd (charge injected at breakdown) of 40 C.cm−2 were obtained for oxide thicknesses ranging from 8 to 10 nm. These compare favorably with our better standard oxides grown at 900°C with 2% HCI in O2. We can thus conclude that RTO is a very promising process for submicron technologies.