bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Influence Of Stress on The Growth of Titanium Silicide Thin Films on (001) Silicon Substrates
Authors: Cheng S. L. , Chang S. M. , Huang H. Y. , Peng Y. C. , Chen L. J. , Tsui B. Y , Tsai C. J. , Guo S. S. 
Published: April 2011

AbstractThe influence of stress on the enhanced formation of C54-TiSi2 phase has been investigated. Tensile stress induced by backside CoSi2 film on the silicon substrate has been found to enhance the growth of C54-TiSi2 on (001)Si. The thickness of amorphous interlayers (a-interlayers) between Ti films and silicon substrates was found to be thicker and thinner in the tensilly and compressively stressed samples, respectively. From auto-correlation function analysis, the thicker a-interlayer was found to consist of a higher density of crystallites. The crystallites provide nucleation sites for C49-TiSi2 and facilitate the formation of C49-TiSi2 of small size. The larger total area of C49-TiSi2 grain boundaries supplies more nucleation sites for the phase transformation of C49- to C54-TiSi2. Therefore, the tensile stress present in the silicon substrate promotes the formation of a-interlayer and decreases the grain size of C49- TiSi2, which increases the nucleation density of the C54-TiSi2 phase. As a result, the transformation of C49- to C54-TiSi2 phase is enhanced.
Multilevel Damascene Interconnection in Integration of MOCVD Cu and Low-k Fluorinated Amorphous Carbon
Authors: Yang Hongning , Evans David R. , Nguyen Tue , Stecker Lisa H. , Ulrich Bruce , Hsu S.-T. 
Published: April 2011

AbstractIn this paper, we present studies on the integration process of CVD Cu with low-k fluorinated amorphous carbon (a-F:C) in single level and multilevel damascene structure. A thin layer of adhesion promoter material, SiC:H, was utilized to enhance the adhesion and mechanical properties of the damascene stacking layers. The SiC:H layer could also serve as a barrier to contain fluorine atoms from diffusion. The improved a-F:C damascene stacking layers are able to sustain the process of CMP, heat treatment, patterning and plasma etching. The fabrication of single and multi-level damascene structures is proved to be feasible. Some of the electrical performance data evaluated on the Cu/a-F:C damascene structure will be also presented in this paper.
Integration Challenges of Inorganic Low-K (K≤2.5) Materials with CU for Sub-0.25μm Multilevel Interconnects
Authors: Yu K. C. , Defilippi J. , Tiwari R. , Sparks T. , Smith D. , Olivares M. , Selinidis S. , Zhang J. , Junker K. , Braekelmann G. , Farkas J. , Lee K. S. , Filipiak S. , Lindell M. , Watanabe J. K. , Wetzel J. T. , Jawarani D. , Herrick M. T. , Cave N. G. , Hobbs C. C. , Stankus J. J. , Mora R. , Freeman M. , Van Gompel T. , Denning D. , Fowler B. W. , Garcia S. , Newton T. , Pena D. , Keyes C. , Nguyen T. , Kirksey S. , Neil T. , Conner J. , Lee J. J. , Fox R. , Hershey R. , Crabtree P. , Sieloff D. D. , Blumenthal R. , Weitzman E. J. 
Published: April 2011

AbstractThe recent introduction of dual inlaid Cu and oxide based interconnects within sub-0.25μm CMOS technology has delivered higher performance and lower power devices. Further speed improvements and power reduction may be achieved by reducing the interconnect parasitic capacitance through integration of low-k interlevel dielectric (ILD) materials with Cu. This paper demonstrates successful multi-level dual inlaid Cu/low-k interconnects with ILD permittivities ranging from 2.0 to 2.5. Integration challenges specific to inorganic low-k and Cu based structures are discussed. Through advanced CMP process development, multi-level integration of porous oxide materials with moduli less than 0.5 GPa is demonstrated. Parametric data and isothermal annealing of these Cu/ low-k structures show results with yield comparable to Cu/oxide based interconnects.
Integration Issues for Low Dielectric Constant Materials in each Generation of ULSI'S
Authors: Gomi Hideki , Kishimoto Koji , Usami Tatsuya , Koyanagi Ken-ichi , Yokoyama Takashi , Oda Noriaki , Matsubara Yoshihisa 
Published: April 2011

AbstractThe technologies utilizing Fluorinated Silicon Oxide (FSG, k=3.6) and Hydrogen Silsesquioxane (HSQ, k=3.0) have been established for 0.25-μm and 0.18-μm generation ULSIs. However, low-k materials for the next generation ULSIs, which have a dielectric constant of less than 3.0, have not become mature yet. In this paper, we review process integration issues in applying FSG and HSQ, and describe integration results and device performance using Fluorinated Amorphous Carbon (a-C:F, k=2.5) as one of the promising low-k materials for the next generation ULSIs.
Rapid Thermal Processing of Hydrogen Silsesquioxane for Low Dielectric Constant Performance
Authors: Bremmer J. N. , Gray D. , Liu Y. , Gruszynski K. , Marcus S. 
Published: April 2011

AbstractLow dielectric constant hydrogen silsesquioxane films were achieved by rapid thermal cure processing with production viable equipment. A reduced dielectric constant of k = 2.5–2.6 is demonstrated by optimizing rapid thermal cure process conditions to produce low density hydrogen silsesquioxane thin films. This is a significant reduction relative to production proven furnace cure processed hydrogen silsesquioxane with k = 2.9. Concurrent with reduced k performance is a characteristic film expansion which contributes to formation of a low density structure. A mechanism for film expansion and relevance to low k performance is described; and issues relative to integration of rapid thermal processed low k hydrogen silsesquioxane are discussed.
Amorphous Carbon Nitride Films as a Candidate for Low Dielectric Constant Materials
Authors: Aono M. , Nitta S. , Iwasaki T. , Yokoi H. , Itoh T. , Nonomura S. 
Published: April 2011

AbstractWe have succeeded to prepare high resistivity and rather low dielectric constant amorphous carbon nitride films a-CNx (0.52<x<0.86) by the reactive radio frequency magnetron sputtering of a graphite target using nitrogen molecules as a sputter gas.The resistivity of a-CNx are 5×1016 to 1017 Ω-cm and be estimated to 1020 Ω-cm, when the ratio of the carbon and nitrogen becomes chemically stoichiometry 3 to 4, i.e. C3N4. The resistivity of a-CNx films prepared by a layer-by-layer method, LL-a-CNx, is 1018 Ω -cm for x=0.6. The layer-by-layer method is a cyclic process of a deposition by the sputtering and an etching by atomic hydrogen. The sample LL-a-CNx made by a layer-by-layer method are compared with that of usual method a-CNx. The dielectric constant of a-CNx films calculated from the refractive index n are 3.6 to 2.8 corresponds to nitrogen contents, 0.52<x<0.86. The dielectric constants ε of a-CNx films decrease with the content of nitrogen x. At an ultimate component of a-CNx, at x=4/3, the dielectric constant is estimated to 1.8.
Mechanisms of Mound Coarsening in Unstable Epitaxial Growth
Authors: Amar Jacques G. 
Published: April 2011

ABSTRACTThe effects of various island and mound relaxation mechanisms on the mound morphology and asymptotic mound coarsening exponent n are investigated for growth on fcc/bcc(001) and fcc (111) metal surfaces. While the strength of the diffusion bias (due for example to an Ehrlich-Schwoebel step barrier) affects the crossover time, the presence or absence of corner diffusion is found to play a crucial role in determining the asymptotic value of the coarsening exponent. In the absence of island-relaxation or in the case of island-relaxation without rapid corner diffusion the asymptotic exponent is found to satisfy n ≃ 1/4. However, when rapid corner-diffusion is allowed, the coarsening exponent is found to approach 1/3. For the case of reversible island growth a strong step-barrier leads to an effective corner diffusion so that a growth exponent of either 1/4 or 1/3 may be observed depending on the strength of the step-barrier. These results appear to account for recent experimental observations of a large coarsening exponent (n ≃ 0.33) in epitaxial growth of Rh/Rh(111) at high temperature as well as of a smaller coarsening exponent (n ≃ 1/4) observed in epitaxial growth of Fe/Fe(001) and Cu/Cu(001). An explanation for these results is also presented in terms of the effects of corner diffusion on the surface current and mound morphology.
Self-Organization of Surface Patterns during Clustering
Authors: Zinke–Allmang Martin , Hul'ko Oleksa , Brongersma Sywert , Carlow Graham 
Published: April 2011

ABSTRACTOstwald ripening, early stage and late stage coalescence growth are well–characterized, fundamental late–stage processes in the phase separation of thin film deposits on surfaces. These processes have recently been studied in respect to ordering of the clustered phase. While late stage coalescence growth is associated with random positions of the growing clusters, partial ordering is observed for early stage coalescence and ripeningTo obtain even higher order of clustering, additional physical driving forces must be included in the process. Two examples are discussed, one utilizing vertical correlation of clusters in super-lattice growth of coherent Stranski–Krastanov structures (coalescence based structures) and a novel concept based on preferential secondary clustering based on ripening morphologies.
Initial Strain Relaxation in S0.91Ge0.09/Si Superlattice Structures via Misfit-Dislocations
Authors: Leininger J. , U'ren G. D. , Goorsky M. S. 
Published: April 2011

ABSTRACTWe addressed the initial strain relaxation of symmetric 95 Å period Si0.91Ge0.09/Si heterostructures grown by ultra-high vacuum chemical vapor deposition on vicinal substrates miscut 2.04° from (001) in a direction 36° from a [110]. Double-axis x-ray topography revealed misfit-dislocation sources in the as-grown samples with an average density of about 60 cm−2, although the distribution of these sites was not homogeneous. The progression of dislocation nucleation and growth was observed during subsequent rapid thermal annealing (800°C, 20s-320s). Physical heterogeneities were identified as dislocation sources, and they gave rise to orthogonal misfit dislocation bundles, which on a macroscopic scale resemble crosses. Upon longer annealing, a more homogeneous distribution of defects was observed without measurable relaxation. These original defects did propagate; however, they did not spur a cross-slip multiplication sequence.
Homoepitaxial Growth of Si at Low Temperature (325 °C)
Authors: Platen J. , Selle B. , Sieber I. , Zeimer U. , Fuhs W. 
Published: April 2011

ABSTRACTElectron cyclotron resonance chemical vapor deposition (ECR-CVD) is used to grow to prepare epitaxial films on Si(100), Si(111), and Si(311) at 325 °C with a growth rate of 10…12 nm/min. On Si(100) up to a layer thickness of more than 300 nm the films exhibit a well defined and smooth interface and a perfectly ordered lattice structure. Beyond a critical thickness of about 500 nm the formation of conically shaped, amorphous regions was observed. At a thickness of 1.6 µm only 10… 15 % of the surface consists of these amorphous cones. On Si(311), Si(111), and Si(011) the critical epitaxial thicknesses hepi depends on the crystallographic orientation of the substrate in the sequence hepi(311) > hepi(111) > hepi(011) with an abrupt change of the film structure from crystalline to amorphous
High Temperature Stable WSi2-Contacts on p-6H-Silicon Carbide
Authors: Erler Frank , Romanus Henry , Lindner Jörg K. N. , Spiess Lothar 
Published: April 2011

ABSTRACTAmorphous tungsten-silicon layers were deposited by DC co-sputtering and subsequently annealed in an argon atmosphere up to 1325 K to form tetragonal crystalline WSi2. Al-implanted p-6H-SiC exhibits a small depletion area forming an ohmic contact with low specific contact resistance. A modified Circular Transmission Line Model (CTLM), introduced by Marlow & Das [1] and Reeves [2], was used to characterize the electrical properties of the prepared contacts in the range between 300 K and 650 K. Deviations between calculated fieldemission contact resistances and measured contact resistances (ρc=2·10−2 Ωcm2, T=650 K) could be explained by TEM-cross section investigations. These deviations are caused by inhomogeneous contact interfaces originating from technological difficulties during contact preparation.
Oxidation Modelling for SiC
Authors: Wright N. G. , Johnson C. M. , O'neill A. G. 
Published: April 2011

ABSTRACTA simple mechanistic model of the oxidation of SiC is presented and analysed using Monte- Carlo simulation techniques. The model explains the observed anisotropic oxidation rate of SiC in terms of the effect of weakening/strengthening of Si-C bonds arising from the ongoing incorporation of highly electronegative oxygen atoms into the crystal lattice. The extraction of key process metrics (such as oxide thickness, interface roughness and oxide defect density) from the Monte-Carlo simulations is discussed.
Effect of Ge on SiC Film Morphology in SiC/Si Films Grown by MOCVD
Authors: Samey W. L. , Salamanca-Riba L. , Zhou P. , Spencer M. G. , Taylor C. , Sharma R. P. , Jones K. A. 
Published: April 2011

ABSTRACTSiC/Si films generally contain stacking faults and amorphous regions near the interface. High quality SiC/Si films are especially difficult to obtain since the temperatures usually required to grow high quality SiC are above the Si melting point. We added Ge in the form of GeH2 to the reactant gases to promote two-dimensional CVD growth of SiC films on (111) Si substrates at 1000°C. The films grown with no Ge are essentially amorphous with very small crystalline regions, whereas those films grown with GeH2 flow rates of 10 and 15 sccm are polycrystalline with the 3C structure. Increasing the flow rate to 20 sccm improves the crystallinity and induces growth of 6H SiC over an initial 3C layer. This study presents the first observation of spontaneous polytype transformation in SiC grown on Si by MOCVD.
Properties of Heteroepitaxial 3C-SiC Layer on Si Using Si2(CH3)6 by CVD
Authors: Chen Y. , Masuda Y. , Nishlo Y. , Matsumoto K. , Nishino S. 
Published: April 2011

ABSTRACTSingle crystal cubic silicon carbide ( 3C-SiC ) has been deposited on Si(100) by atmospheric CVD at 1350°C using Si2(CH3)6. The 3C-SiC epilayers were characterized by XRD, Raman scattering and photoluminescence (PL). The 3C-SiC distinct TO near 796 cm−1 and LO near 973 cm−1 were recorded by Raman measurement. The PL spectra of SiC films at 11K included the nitrogen-bound exciton (N-BE) lines, the ‘defect-related’ W band near 2.15eV, and 2.13eV peak corresponding to D-A pair recombination as well as the ‘divacancy-related’ D 1 peak at 1.97eV. The thickness dependences of Raman and PL measurement were made and it was observed that tensile stress and strain in films decrease with increasing film thickness. Electrical properties of the films were measured by making schottky diodes and using Van der Pauw method. Above 300K, the electron mobility changed as μH ∼ T−1.45 ∼ −1.56 and the highest mobility was about 400 cm2V−1s−1 at room temperature. In 3C-SiC the scattering processes are affected prominently by acoustic scattering in this temperature range.
Characterization of Vanadium-Doped 4H-SiC Using Optical Admittance Spectroscopy
Authors: Smith S. R. , Evwaraye A. O. , Mitchel W. C. , Solomon J. S. , Goldstein J. 
Published: April 2011

ABSTRACTVanadium is an important dopant in SiC because it gives rise to donor levels near the middle of the bandgap which can be used to make the material semi-insulating, and semiinsulating material has many applications as a substrate material for high-power electronics. However, conventional means of characterizing electronic levels in the bandgap of the material require very high temperatures, in the neighborhood of 650–800 °C, in order to move the Fermi level to midgap and cause ionization of the V donors. The technique of Optical Admittance Spectroscopy permits the ionization of the midgap donors using light of the appropriate energy, and thus avoids the need for high temperatures. Using this technique we have examined several specimens of V-doped and high-resistivity 4H-SiC. We have identified levels previously associated with V, and new levels we attribute to Ti. Pinning of the Fermi level in some specimens was verified by high-temperature Hall effect measurements. SIMS measurements were used to determine impurity concentrations. IR absorption measurements were correlated with the Ti, V, and Cr concentrations determined by SIMS.
Online Monitoring of PVT SiC Bulk Crystal Growth Using Digital X-Ray Imaging
Authors: Wellmann P. J. , Bickermann M. , Grau M. , Hofmann D. , Straubinger T. L. , Winnacker A. 
Published: April 2011

ABSTRACTAn advanced method based on x-ray imaging is presented which allows us to visualize the ongoing processes during physical vapor transport (PVT) growth of SiC. Using a high resolution and high speed x-ray imaging detector based on image plates and digital recording we are able to follow the SiC bulk single crystal growth as well as the evolution of the SiC powder source inside the inductively heated graphite crucible on-line and quasi-continuously.
Pendeo-Epitaxial Growth of GaN on SiC and Silicon Substrates via Metalorganic Chemical Vapor Deposition
Authors: Linthicum K. J. , Gehrke T. , Thomson D. , Ronning C. , Carlson E. P. , Zorman C. A. , Mehregany M. , Davis R. F. 
Published: April 2011

ABSTRACTPendeo-epitaxial lateral growth (PE) of GaN epilayers on (0001) 6H-silicon carbide and (011) Si substrates has been achieved. Growth on the latter substrate was accomplished through the use of a 3C-SiC transition layer. The coalesced PE GaN epilayers were characterized using scanning electron diffraction, x-ray diffraction and photoluminescence spectroscopy. The regions of lateral growth exhibited ∼0.2° crystallographic tilt relative to the seed layer. The GaN seed and PE epilayers grown on the 3C-SiC/Si substrates exhibited comparable optical characteristics to the GaN seed and PE grown on 6H-SiC substrates. The near band-edge emission of the GaN/3C-SiC/Si seed was 3.450 eV (FWHM ∼ 19 meV) and the GaN/6H-SiC seed was 3.466 eV (FWHM ∼ 4 meV).
Maskless Lateral Epitaxial Overgrowth of GaN on Sapphire
Authors: Fini P. , Marchand H. , Ibbetson J. P. , Moran B. , Zhao L. , Denbaars S. P. , Speck J. S. , Mishra U. K. 
Published: April 2011

ABSTRACTWe demonstrate a technique of lateral epitaxial overgrowth (LEO) of GaN, termed 'maskless' LEO, in which no mask is deposited prior to LEO regrowth. Instead, a bulk (> 2 μm) GaN layer on sapphire is selectively dry etched, leaving ∼5 μm-wide stripe mesas oriented in the <1010>GaN direction, with a 20 μm period. These stripes serve as seeds for LEO GaN growth, which proceeds from the tops of the stripes and expands laterally, resulting in a ‘T’, or overhang, morphology. As for LEO over an SiO2 mask, significant defect reduction (from ∼109 cm−2 to ∼106 cm−2 ) is observed in cross-sectional transmission electron microscopy (TEM). Atomic force microscopy of the top surface of the LEO GaN reveals that no threading dislocations with screw component terminate at the surfaces of laterally overgrown regions. X-ray diffraction measurements reveal that the wings exhibit a crystallographic tilt away from the seed regions in an azimuth perpendicular to the stripe direction; the tilt angle (∼0.4 – 0.5°) is relatively independent of growth temperature and wing aspect ratio.
Ca Dopant Site Within Ion Implanted GaN Lattice
Authors: Kobayashi H. , Gibson W. M. 
Published: April 2011

ABSTRACTWe have investigated the Ca dopant site within the GaN lattice using ion channeling in combination with Rutherford backscattering spectrometry (RBS), particle induced x ray emission (PIXE) and nuclear reaction analysis (NRA). Metalorganic chemical vapor deposition (MOCVD) grown GaN on c-plane sapphire substrates implanted with 40Ca at a dose of 1×1015 cm−2 with post-implant annealing were investigated. The channeling results indicate that more than 80% of Ca are near Ga sites even in as-implanted samples, however, they are displaced by ∼ 0.2 Å from the Ga sites and that the Ca goes to the exact Ga sites after annealing at 1100°C. We think that the displaced Ca in the as-implanted samples are electrically compensated due to formation of complex defects with donor like point defects, such as CaGa-VN and/or CaGa-GaN, and that CaGa becomes electrically active when these complex defects are broken and the point defects diffuse away with annealing at 1100°C.
Characterization of SiO2/SiC Samples Using Photoelectron Spectroscopy
Authors: Johansson L. I. , Glans P- A. , Wahab Q. , Grehk T. M. , Eickhoff T. H. , Drube W. 
Published: April 2011

ABSTRACTThe results of photoemission studies of SiO2/SiC samples for the purpose of revealing presence of any carbon containing by-products at the interface are reported. Two components could be identified in recorded Si 2p and C ls core level spectra. For Si 2p these were identified to originate from SiO2 and SiC while for C ls they were interpreted to originate from graphite like carbon and SiC. The variation in relative intensity of these components with emission angle was first investigated. Thereafter the intensity of the different components were studied after successive Ar+-sputtering cycles. Both experiments showed contribution from graphite like carbon on top of the oxide but not at the interface.
SIMS and Cl Characterization of Manganese-Doped Aluminum Nitride Films
Authors: Tucceri R. C. , Bland C. D. , Caldwell M. L. , Ervin M. H. , Magtoto N. P. , Spalding C. M. , Wood M. A. , Richardson H. H. 
Published: April 2011

ABSTRACTWe have recently carried out MOCVD experiments that showed for the first time the doping of AlN thin films with manganese. Films of AlN that were doped with less than 0.1% of manganese showed emission bands at 427 nm, 488 nm and 600 nm in accordance with previous published excitation and emission spectra of manganese incorporated in bulk A1N. A film with a higher percentage of manganese (1.7%) grown on top of a pure A1N layer (underlayer) showed weak emission at 601 nm. A portion of the underlayer not covered during growth of the overlayer has a very strong emission band at 408 nm and a weaker band at 605 nm. SIMS and EDX analyses of this film revealed both carbon and oxygen contamination as well as diffusion of manganese into the A1N underlayer. The band at 408 nm is associated with direct gap emission from oxygen contaminated A1N and the band at 605 nm is from manganese incorporated by diffusion into the A1N underlayer.
Disorder Induced IR Anomaly in Hexagonal AlGaN Short-Period Superlattices and Alloys
Authors: Mintairov A. M. , Vlasov A. S. , Merz J. L. , Korakakis D. , Moustakas T. D. , Osinsky A. O. , Gaska R. , Smirnov M. B. 
Published: April 2011

ABSTRACTWe report an experimental (infrared reflectance spectroscopy) and theoretical study of the polar optical phonons in hexagonal ternary nitride compounds: AlNm/GaNn (n=2-8, m=4, 8) superlattices (SL) and spontaneously ordered AlxGa1−xN (x=0.08–0.55) alloys. In infrared (IR) reflectivity spectra we revealed two modes having strong LO-TO splitting (20–150 cm−1), and several modes, having a small (1–3 cm−1) LO-TO splitting. All modes have a very high damping parameter ≥20 cm−1. The unusual observation is the negative value of the oscillator strength for the weak IR mode at ∼690 cm−1, suggesting possible lattice instability, consistent with high damping observed. We found from lattice dynamical calculations that weak IR active modes correspond to modes localized at GaN-AlN interfaces. Our analysis has shown that an anomalous mode is induced by the disorder effects and arises due to strong overlapping of the LO-TO phonon branches of the bulk GaN and AlN. In SL samples the anomalous mode corresponds to phonons localized on interface inhomogenities.