bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reliability Issues of a Crack-Resistant Passivation Layer Process for Sub-Micron Non-Volatile Memory Technology
Authors: Moinpour Mansour , Chu John , Lubic Karen , Moghadam Farhad 
Published: March 2011

AbstractChemically vapor deposited phosphosilicate glass (PSG) has been used extensively for final passivation on EPROM and other Non Volatile Memory (NVM) technologies. The maximum amount of phosphorous that can be added to the passivation oxide (post metallization) is constrained by the stability of the as-deposited, undensified film. Atmosphericpressure chemically vapor deposited films of various dopant levels ranging from pure PSG to various boron and phosphorous wt%BPSG films were studied with respect to their passivation properties. The film performance with respect to passivation crack resistance, step coverage, and impacts on metal cracks/voids was evaluated. It was found that the crack resistance was by far more sensitive to boron concentration than that of phosphorous in the undensified film. The crack resistance is shown to be dependent on the as-deposited film densities, moisture levels and amount of shrinkage after a 400° C alloy/anneal. Other important parameters such as stress levels, UV transparency and sodium gettering capabilities were investigated. Reliability data on packaged-device level testing (both ceramic and plastic units) are also presented.
Iron Redistribution in Aluminum Thin Films
Authors: Barr David L. , Gualtieri G.J. , Case C.B. , Marcus M.A. , Brown W.L. 
Published: March 2011

AbstractStrongly non uniform Fe depth distributions have been observed in AI(0.13 at% Fe) thin films deposited at temperatures of 350ºC and above. The concentration of Fe is uniform in depth at a deposition temperature of 300ºC but is increasingly enhanced toward the substrate interface at 450ºC. Subsequent annealing produces only a slight redistribution of Fe. The Fe is primarily present as precipitates smaller than 100 nm. A model of grain boundary diffusion of Fe and precipitate formation and grain growth is proposed to explain the observed behavior.
A Fresh Insight into Film Morphology Measurement Techniques for Advanced Ulsi Manufacturing
Authors: Ramaswami Seshadri 
Published: March 2011

AbstractA laser based non-destructive technique has been used to study the morphology of sputterdeposited aluminum alloy films. The data emanating from the Therma-wave Imager that makes use of this principle, has been correlated with reflectivity, grain size and micro-roughness of the film. In addition, through the use of a case study, this paper demonstrates the utility of this application as an in-line monitor in an integrated circuit fabrication line.
Observation of Reduced Oxidation Rates for Plasmaassisted CVD Copper Films
Authors: Ding P. J. , Zheng B. , Eisenbraun E. T. , Lanford W. A. , Kaloyeros A. E. , Hymes S. , Murarka S. P. 
Published: March 2011

AbstractOxidation kinetics of plasma-assisted chemical vapor deposited (PA-CVD) copper films were investigated using Rutherford backscattering spectrometry (RBS). The PA-CVD copper films were deposited using hydrogen plasma reduction of bis(hexafluoroacetylacetonato) copper(II), Cu(hfa)2, precursor. Under identical experimental conditions, PA-CVD copper films oxidize more slowly than sputtered copper films. This decrease in oxidationis manifested both as a time delay at the beginning of the oxidation of the PA-CVD copper films and as a decrease in the rate of oxide growth at oxidation temperatures of 200ºC and below. The possivation appears to be caused by the hydrogen plasma present during depostion.
In Situ Xps Studies of the Deposition of Thin Films from Tetrakis(Dimethylamido)Titaniumorganometaluc Precursor for Diffusion Barriers
Authors: Ruhl G. , Rehmet R. , Knoživá M. , Vepřek S. 
Published: March 2011

AbstractWith the decreasing minimum feature size of integrated microcircuits, a low-temperature, chlorine-free CVD process is needed for the deposition of TiN diffusion barriers. A problem during the thermal deposition of titanium nitride from organometallic precursors, such as tetrakis(dimethylamido)titanium, is the high content of carbon in the films. In situ XPS study reveals that most of the carbon is present as CHx inclusions with a smaller but not negligible amount of carbidic component. This can be avoided by using ammonia, but the high rate of the reaction in the gas phase makes the control of the film growth difficult. Most of the problems can be resolved when using hydrogen afterglow.
Stability of Silicide Films Under Post-Annealing: a Dopant Effect
Authors: Shepard C.L. , Lanford W.A. , Pant A.K. , Murarka S. P. 
Published: March 2011

AbstractThe formation of PtSi films by rapid thermal processing of e-beam evaporated Pt on <100> Si has been studied. The current study found that PtSi films have the potentially useful property of oxidizing, i.e., forming a surface layer of Si02 which may be useful for patterning. Rapid oxide formation is found with, possibly, linear growth rates when the film is doped with As to 8E15 atoms/cm2 at 80 KeV but insignificant oxidation if the film is undoped or B-doped. Rutherford backscattering analysis shows significant redistribution of the As during silicidation and oxidation with As excluded from the silicide, diffusing to the oxide and especially the oxide surface. Post-silicidation anneals have been done in a conventional tube furnace at 650ºC for up to 60 minutes and form an oxide thickness of up to 200 nm. NiSi films appear stable if Bdoped, oxidize with Ni piling up at the Si02/Si interface if undoped, and are unstable with Ni diffusing deep into the Si if As-doped.
Amorphous Carbon as a Diffusion Barrier to Copper
Authors: Purser Richard G. , Strane Jay W. , Mayer James W. 
Published: March 2011

AbstractAmorphous carbon was evaluated as a diffusion barrier between Cu and Si. Samples were annealed at 500 ºC for 1 hour in vacuum. Barrier properties were characterized for metallurgical failure with RBS and XTEM, and electrical properties were characterized with pn junction diodes and MOS capacitors. RBS and X-TEM showed that a barrier 13.5 nm thick prevented Cu and Si diffusion during the anneal. The diodes remained rectifying after annealing, although the series resistance went up. C-V measurements of the capacitors did not show the hysteresis that is typical of mobile charge in the oxide. The barrier breakdown mechanism is diffusion through the amorphous structure.
Oxide Degradation Resulting from Photoresist Ashing
Authors: Mikulan P. I. , Koo T. T. , Awadelkarim O. O. , Fonash S. J. , Ta T. , Chan Y. D. 
Published: March 2011

AbstractIn this study, possible SiO2 damage that could result from several different photoresist ashing techniques has been assessed using patterned photoresist over blanket oxides. The types of ashing systems used were RF power (RF), upstream ozone generator (Upstream) and two microwave power reactors (Microwave 1 and Microwave 2). Aluminum capacitors were evaporated on the samples after the ashing for oxide evaluation. Electrical characterization of these MOS structures included capacitance verses voltage and time dependent dielectric breakdown measurements. We also looked for Si substrate damage in these samples using deep level transient spectroscopy and Schottky barrier current-voltage measurements. This characterization showed oxide damage varied widely with ashing tool. In all cases, however, there was no significant Si substrate damage.
The Role of Texture On The Reliability Of Aluminum Based Interconnects
Authors: Knorr David B. 
Published: March 2011

AbstractPreferred crystallographic orientation has long been recognized to play an important role in interconnect reliability where a strong (111) texture improves electromigration lifetime. Detailed microstructural analyses have enabled the role of texture to be better understood. Although Bragg-Brentano scans are often used to characterize texture, it is shown that this technique gives incomplete and sometimes misleading information. The pole figure technique provides a complete description of the texture. The measurement and presentation of textures consider experimental aspects unique to thin film analysis as a prerequisite to developing quality data. Five textural archetypes are identified, and metrics presented for their quantification. Processing effects on texture are complex and depend on all facets of deposition conditions, on substrate/underlayers, and on annealing. General trends and specific examples of the impact of each aspect are given where it will be shown that deposition conditions and the presence of underlayers have the greatest influence. The role of texture on reliability is considered for four failure modes: thermal hillocks, grain collapse, stress voiding, and electromigration. Electromigration results are emphasized where texture must be considered in the context of grain structure, in general, and, more specifically, the ratio of line width to grain size. Most measures of microstructure and reliability are statistical. The importance of local microstructural analysis will be emphasized in terms of both the arrangement of grains relative to the line dimension and microtexture characterization of the grain-to-grain misorientations.
The Effect of Collimation On Sputtered Alcusi and Almg Microstructures And Electromigration Failure Characteristics
Authors: Licata Thomas J. , Sullivan Timothy D. , Bass Roy S. , Ryan James G. , Knorr David B. 
Published: March 2011

AbstractIncreasing circuit densities produce higher metal wiring aspect ratios, and more difficult feature fill for damascene processing. One method of extending the use of sputter deposition to challenging aspect ratios is to collimate the sputtered flux using a collimator plate, and to avoid randomizing the collimated flux by using low process pressures corresponding to long sputtered atom mean free paths. In this paper, we discuss our fabrication of damascene AI-0.5Cu-2Si and AI-2Mg wiring using both collimated and uncollimated sputtering, and our observations of collimation-induced changes in Al alloy electromigration and microstructure. Our experiments show that collimation has only a small effect on AlCuSi, but a large effect on AIMg. Specifically, the median time to electromigration failure for collimated AIMg was ∼10X the value for uncollimated AlMg and ∼6X the values for collimated and uncollimated AlCuSi. Transmission electron microscope and x-ray diffraction analyses of these films show that the collimation-induced improvement in AIMg t50 is associated with the formation of smaller, lower strain grains which are clustered in very well-oriented (111) domains. We propose that the advantageous AlMg microstructure results from enhanced texture produced by aspects of the collimated deposition active in the absence of incoherent precipitates.
Continuum Model of Epitaxial Roughening
Authors: G. Amar Jacques , Family Fereydoon 
Published: March 2011

ABSTRACTA continuum equation for epitaxial and thin-film growth in which diffusion along the surface is the dominant relaxation process and the full diffusion along the surface is taken into account, is studied. The interface width is found to grow linearly with time (height) in agreement with recent experiments. At late times dynamic scaling breaks down and the surface develops a characteristic morphology which is similar to that found in experiments.
Epitaxial Growth of Eute on Pbte (111) Influenced by Strain-Induced Coherent 3D Islanding
Authors: Springholz G. , Bauer G. , Schilcher K. 
Published: March 2011

ABSTRACTEuTe on PbTe is an example of a strained layer heteroepitaxial system with a moderate lattice-Mismatch of 2%. Using reflection high-energy electron diffraction (RHEED), the phase diagram of heteroepitaxial growth of EuTe on PbTe (111) by molecular beam epitaxy was established, indicating that only in a narrow regime of growth conditions does two dimensional layer-by-layer growth occur. Using in situ RHEED, combined with ex situ atomic force Microscopy, the evolution of the surface morphology during heteroepitaxial growth was investigated. It is found that at the critical layer thickness an abrupt surface roughening occurs. Studying the dependence of this surface roughening transition on substrate temperature and on the Eu-to-Te2 beam flux ratio used for growth, the critical layer thickness is found to decrease strongly as the surface kinetics are enhanced, even if the substrate temperature is kept constant. These results indicate that the surface roughening is driven only by the surface kinetics, which strongly supports the model of strain relaxation by coherent three dimensional islanding.
Measurement of Lattice Relaxation During Epitaxy Using Tunneling Microscopy: Ge on Si(111)
Authors: Theiss Silva K. , Chen D.M. , Golovchenko J.A. 
Published: March 2011

ABSTRACTWe have used the tunneling microscope to measure the lattice relaxation of Ge islands on Si (111) as a function of their height. Lattice constants on the top surfaces of individual Ge islands can be measured with an uncertainty of approximately one percent. The lattice constant is a continuous, Monotonically increasing function of island height up to 20 bilayers. At heights around 5O bilayers, the island-top lattice parameter may exceed that of bulk Ge. Defects can be observed penetrating the top surface of islands which have heights around 90 bilayers.
Sem Analysis of the Nucleation of Tin Oxide Films on Glass Surfaces
Authors: Mao Limin , Benoit Robert E. , Proscia James W. 
Published: March 2011

ABSTRACTFluorine-doped tin oxide films were produced by atmospheric pressure chemical vapor deposition (APCVD) from the reaction of tin tetrachloride, water, and difluoroethanc. Tin oxide films deposited on glass substrates containing high sodium concentrations tended to be of lower quality with higher resistivities than films deposited on low sodium glass. Scanning electron Microscopy (SEM) was used to study the differences in film nucleation on the high and low sodium containing glass substrates. Eiarly in the nuclcation process, individual grains of tin oxide crystals arc observed to be distributed discontinuously over the substrates. As the deposition time was increased the number of nucleation sites increased and the individual grains became larger. The number of nucleation sites was consistently higher on the high sodium glass. However, numerous inclusions of sodium chloride crystals were observed by EDX in the tin oxide films deposited on the high sodium glass. SEM cross sections revealed how the film growth converted from the grains, which initially nucleated on the glass surface, to columns in the direction perpendicular to the substrate surface. Results for tin oxide grown on sodium-containing glass over coated with silica are also be presented.
Growth of Cuinse2 on (lOO) Gaas by Molecular Beam Epitaxy
Authors: Tseng Bae-Heng , Lin Song-Bin 
Published: March 2011

ABSTRACTDomain-free epitaxial layer of CuInSe2 has been successfully grown on (lOO) GaAs at the substrate temperature above 470°C. Both TEM and X-ray analyses were performed to verify this result. The CuInSe2/GaAs interface was examined by high resolution TEM. For films high in indium, InSe was identifed by X-ray diffraction. TEM observations showed that the InSe precipitates were rectangular in shape and the habit plane was determined to be (110). Photo-assisted MBE technique had also been used for the growth of CuInSe2 films with high crystalline quality. The epitaxial temperature was significantly reduced to 300°C.
Epitaxial Growth of Titanium Nitride Films On (100) Silicon Three-Dimensional Heterostructures: Processing and Characterization
Authors: Chowdhury Rina , Biunno N. , Narayan J. 
Published: March 2011

ABSTRACTWe have shown that epitaxial films can be grown on highly lattice mismatch systems by domain epitaxial growth. For titanium nitride films on (100) silicon substrates, it is shown that epitaxial growth can occur by Matching M TiN = n asi, where M and n are simple integers with values of 4 and 3 respectively, giving rise to less than 4.0% Misfit. We have investigated the formation of epitaxial titanium nitride films grown on (100) Si by pulsed laser (KrF: λ = 248 nm, τ = 25 ns) physical vapor deposition technique at different substrate temperatures, ranging from 200°C to 600°C. After optimizing the deposition conditions for epitaxial TiN film on Si, we have grown epitaxial silicon film on TiN. The epitaxial relationship was found to be <100> Si ∥ <100> TiN π <100> Si. This semiconductor-Metal-semiconductor device configuration has potential applications in three-dimensional integrated circuits and radiation hardened devices. The success of this technology is predicted on our understanding of: (a) defects at interfaces of Si/TiN/Si, and (b) stresses/strains at interfaces. This paper focuses on the nature of epitaxial growth and analyzes the atomic structures of defects at Si/TiN/Si interfaces using high resolution transmission electron Microscopy (HRTEM). These results are correlated with the results from theoretical modeling of Si/TiN/Si heterostructures.
Room Temperature Epitaxy of Al (100) on Si (111)
Authors: Sosnowski Marek , Ramac Samuel , Brown Walter L. , Kim Young O. 
Published: March 2011

ABSTRACTThere are a number of published reports on the epitaxial growth of Al(111) on Si(111) surfaces usually following a high temperature treatment of the Si surface in UHV. In contrast to these results, we have for the first time observed dominant epitaxial growth of Al(100) films on Si(111) surfaces that have been carefully cleaned and hydrogen terminated and not heated prior to effusion cell deposition of Al at room temperature in UHV. X-ray diffraction shows sharp and intense Al (200) diffraction, enhanced by post deposition annealing. Crystal quality and the dominance of Al(100) structure depend strongly on the substrate treatment and the off-cut angle, both of which control the steps on the Si(111) surface. The steps were found responsible for the epitaxial alignment of the film and the substrate lattices. Details of this alignment were observed in TEM cross-sectional images of the interface.
The Template Technique Applied to Epitaxial Growth of CrSi2 on Silicon (111)
Authors: Manan John E. , Long Robert G. , Vantomme André , Nicolet Marc-A. 
Published: March 2011

ABSTRACTThe template growth technique was applied to the growth of CrSi2 thin films on Si(111) by UHV E-gun evaporation. A 4He+ channeling yield of -50% was obtained for an epitaxial -2100 Å-thick film of continuous morphology grown at 450° C The heteroepitaxial relationship is CrSi2 (001) / Si (lll) with CrSi2[210] ∥ Si<110>.In the case of film formation simply via reactive deposition epitaxy (RDE, chromium evaporation onto hot substrates) a severe crystallinity-Morphology tradeoff is always observed. Continuous films are formed at low temperature but no long-range epitaxy is found. On the other hand, high temperature annealing of these films induces the formation of islands that show good epitaxial alignment with the substrate. This tradeoff was addressed with the template growth technique.
Defect-Free Coalescence of Silicon Layers Over SiO2
Authors: Banhart F. , Nagel N. , Phillipp F. , Bauser E. 
Published: March 2011

ABSTRACTDefect-free coalescence of Si layers which grow laterally over partially oxidized Si substrates is achieved in liquid phase epitaxy from indium solution. An adequate design of the oxide pattern on (111) substrates ascertains that the growth fronts of the Si layers merge gradually on the SiO2 and avoids the formation of inclusions or crystallographic defects. Electron Microscopy in diffraction contrast and convergent beam electron diffraction reveal that the epitaxial Si layers bend towards the substrate as they grow laterally over the SiO2 film. The layers straighten out again as they merge and form a perfect seam of coalescence.
Surface Stress Effects on Thin Film Growth
Authors: Cammarata R.C. 
Published: March 2011

ABSTRACTA review of surface and interface stresses relevant to thin film growth is presented. It is shown that surface stress effects that are generally ignored in the analysis of epitaxy can have an influence on the critical thickness for epitaxy, especially at larger Misfits. A discussion of intrinsic stress generation from surface stress is also presented.
Atomistic Calculations on the Surfactant Role of Indium in the Homoepitaxial Growth of Cu on Cu (100)
Authors: Breeman M. , Barkema G.T. , Boerma D.O. 
Published: March 2011

ABSTRACTWe present atomistic calculations for the system In on Cu (100), using the atom-embedding model of Finnis and Sinclair. It was found that the energy banier for Cu adatoms to jump off a descending step is higher than the adatom migration energy, i.e. descending steps form an additional barrier for diffusion. The presence of In atoms at or in step edges or island edges drastically reduces the energy barrier for interlayer diffusion of Cu adatoms. Therefore, we predict that In atoms may be used as surfactants to improve the homoepitaxial growth of Cu on Cu (100), especially in the temperature range between 150 and 200 K.
Ab Initio Quantum Chemical Studies of Hydrogen and Halogen Migration on the Diamond (110) Surface
Authors: Melnik M. S. , Goodwin D. G. , Goddard W. A. 
Published: March 2011

ABSTRACTActivation energies for the migrations of H, F, and Cl on the diamond C(110) surface are calculated by quantum chemical methods using hydrocarbon cluster Models. The calculations include extensive basis sets with Many-body effects at the level of single and double excitations from Hartree-Fock and Complete-Active-Space wavefunctions. The calculated activation barriers for the (1,2) and (1,3) Migrations indicate that such migrations are too slow to compete with gas-surface reactions during chemical-vapor deposition of diamond. However, the (1,4) migrations of both H and Cl are calculated to be sufficiently fast to compete with gas-surface reactions under typical diamond growth conditions.
Strained Layer Epitaxy: The Role of a Capping Layer and mechanism of Strain Compensation in Multilayers Systems
Authors: Lefebvre I. , Priester C. , Allan G. , Lannoo M. 
Published: March 2011

ABSTRACTWithin a valence force field framework, we calculate the critical thickness of a film lattice mismatched to the substrate on which it is epitaxially deposited. A capping layer lattice matched to the substrate is known to enhance the critical thickness. We calculate the efficiency of the capping layer and study how the capping layer thickness modifies this efficiency. We also demonstrate how using a capping layer which is no more lattice matched to the substrate may improve the effect of the capping layer. Extension to strain compensation in multilayer systems is provided. In the case of uncapped systems, or systems with a thick capping layer lattice matched to the substrate, the results we have obtained using a microscopic description are compared to recent results, obtained using continuous classical elasticity.
Density-Functional Study of Chemisorption of Oxygen on Al (111)
Authors: Ramprasad R. , Drabold D. A. , Adams J. B. 
Published: March 2011

ABSTRACTWe present ab initio studies of oxygen adsorption on Al (111) using a density-functional local-orbital method. Our results indicate that, for very low oxygen exposures, the oxygen atoms are incorporated in the first Al (111) layer. For exposures corresponding to approximately a monolayer of oxygen, an ordered oxygen overlayer with the O atoms sitting on the 3-fold sites was seen. These results are consistent with EXAFS experiments. We have also studied clean Al surfaces and have analyzed their surface relaxations.