bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Method Of Measuring Hydrogen Diffusivity By Hydrogen Permeation Technique I: Theoretical Modeling
Authors: Zhang Tong-Yi , Zheng Yong-Ping 
Published: April 2011

ABSTRACTA new model on hydrogen permeation is proposed, considering absorption and desorption processes on the sample surfaces. Analytical solution, satisfying the flux continuity rather than the concentration boundary conditions, is derived from the model. Drift velocity through surface and drift velocity in bulk are introduced and their ratio determines the validity of the time-lag model. When the ratio of drift velocity through surface over that in bulk approaches infinity, the proposed model is reduced to the time-lag one. The diffusivity and the drift velocity through surface can be evaluated by fitting the entire normalized permeation curve. The obtained results can predict the effects of temperature, sample thickness and energy barriers of absorption and desorption on the permeation process. The thickness effect occurred in using the time-lag model is well explained by the effects of absorption and desorption on the permeation process.
Hydrogen Local Vibrational Modes in Compound Semiconductors
Authors: Mccluskey M. D. 
Published: April 2011

ABSTRACTLocal vibrational mode (LVM) spectroscopy of hydrogen and deuterium in GaP, AlSb, ZnSe, and GaN has provided important information about the structures of dopanthydrogen complexes and their interaction with the host lattice. In GaN:Mg, for example, hydrogen binds to a host nitrogen which is adjacent to the magnesium acceptor. In GaP and ZnSe, it has been demonstrated that the temperature dependent shifts of LVM's are proportional to the lattice thermal energy, a consequence of the anharmonic coupling of the local mode to acoustical phonons.Large hydrostatic pressures have been applied to semiconductors to probe the vibrational properties of hydrogen-related complexes. In GaAs, the pressure dependent shifts of the 12C-H and 13C-H stretch modes have positive curvatures, while the shift of the S-H stretch mode has a negative curvature. This may be related to the fact that in the bond-centered C-H complex, the hydrogen is compressed between the carbon acceptor and one gallium host atom, whereas in the S-H complex, the hydrogen occupies an interstitial position and is not crowded by neighboring atoms. If these trends are general, then hydrostatic pressure may be a powerful tool in determining the position of the hydrogen atom(s) in a complex.In AISb. pressure was utilized to resolve a mystery as to why the Se-D complex gives rise to one stretch mode peak while the Se-H stretch mode splits into three peaks. This anomalous splitting is explained in terms of a new resonant interaction between the stretch mode and combination modes involving a wag mode harmonic and extended lattice phonons. The interaction gives rise to vibrational modes with both localized and extended components. When the temperature or hydrostatic pressure is varied, the modes exhibit anti-crossing behavior.
Hydrogen in GaN-Experiments
Authors: Pearton S. J. , LEE J. W. , Wilson R. G. , Zavada J. M. , Weinstein M. G. , Song C. Y. , Stavola M. 
Published: April 2011

ABSTRACTHydrogen is an important component of the gas phase growth chemistry for GaN (eg. NH3, (CH 3)3 Ga)and the processing environment for subsequent device fabrication (eg. SiH4 for dielectric deposition, NH3 or H2 annealing ambients), and is found to readily permeate into heteroepitaxial material at temperatures ≤200°C. Its main effect has been the passivation of Mg acceptors in p-GaN through formation of neutral Mg-H complexes, which can be dissociated through minority-carrier (electron) injection or simple thermal annealing. Atomic hydrogen is also found to passivate a variety of other species in GaN, as detected by a change in the electrical or optical properties of the material. An example is the increase in luminescence efficiency of Er3+ ions in AIN after hydrogenation, through passivation of non-radiative states that would be an alternative path for de-excitation. The injection of hydrogen during a large variety of device fabrication steps has been detected by SIMS profiling using 2H isotopic labeling. Basically all of the acceptor species in GaN, namely Mg, C, Ca and Cd are found to form complexes with hydrogen.
Surface Passivation Of Metal Hydrides For Applications
Authors: Suda S. , Li Z. -P. , Sun Y.-M. , Liu B.-H. , Gao X.-P. 
Published: April 2011

ABSTRACTProperties and characteristics of hydriding alloys are strongly dependent on surface compositions and morphologies. For instance, oxides such as La203 on AB5 alloys and ZrO2 on AB2, AB, and body-centered-cubic (BCC) alloys act as the barriers for the conversion of molecular and ionic hydrogen to atomic hydrogen at the surface, thus reducing the kinetics in both the gas-solid and electrochemical reactions.Alloy surfaces chemically treated by an aqueous F-ion containing solution have been developed to solve such problems. F-treated surfaces exhibit significantly improved characteristics in regard to the hydrogen uptakes and the protection against impurities and electrolyte solution. In addition, highly conductive metallic Ni layers can be formed on the surface of the alloy particles by the fluorination.The authors report the properties and characteristics of fluorinated hydriding alloys, mainly of a typical AB2 Laves phase material which represents the difficult activation characteristics and poor long-term durability during electrochemical charge/discharge cycles.
Hydrogen induced plastic deformation of stainless steel
Authors: Gadgil V. J. , Keima E. G. , Geijselaers H. J. M. 
Published: April 2011

ABSTRACTHydrogen can influence the behaviour of materials significantly. The effects of hydrogen are specially pronounced in high fugacities of hydrogen which can occur at the surface of steels in contact with certain aqueous environments. In this investigation the effect of high fugacity hydrogen on the surface of stainless steel was investigated using electrochemical cathodic charging. Microhardness was measured on the cross section. Transmission electron microscopy was used to investigate the dislocation substructure just below the surface. Computer simulation using finite element method was carried out to estimate the extent and severity of the deformation. The significance of the results are discussed in relation to the loss of ductility due to hydrogen.
Gas Atomization Processing of LaNi5-x.Mm, Modified with Silicon and Tin
Authors: Ting J. , Pecharsky V. K. , Anderson I. E. , Witham C. , Bowman R. C. , Fultz B. 
Published: April 2011

ABSTRACTA high pressure gas atomization (HPGA) process has been employed to study microsegregation in LaNi4.75 Sn0.25 and LaNi4.6Si0.4 alloy powders to serve as a basis for further investigations of low cost production of multicomponent alloys in combination with mishmetal (Mm). This investigation is an attempt to produce high quality powders for battery cathode fabrication that can be used in an as-atomized condition without prolong annealing, hydridingdehydriding, and grinding. Argon atomizing gas was used in the HPGA process of the LaNi4.75Sn0.25 and LaNi4.6Si0.4 alloys to investigate rapid solidification effects on microsegregation. Short annealing treatments of 5 minutes at 900°C were able to homogenize both alloy compositions, eliminating solidification micro-segregation along the grain boundaries phases. The rapid homogenization can be attributed primarily to the refined cell structures in gas-atomized particles that provide short diffusion pathways for the dissolving elements.
Hydrogen/Deuterium Interaction With CMOS Transistor Device Structure: Sintering Process Studied by Sims
Authors: Chen P. J. , Wallace R. M. 
Published: April 2011

ABSTRACTPassivation of the SiO2-Si interface by hydrogen/deuterium in MOS transistors serve to ensure their operating reliability against channel hot carriers. Physical characterization of device sintering process in deuterated forming gas (10%D2:90%N2) is carried out by dynamic SIMS on planar CMOS gate stack structures, in conjunction with device hot carrier electrical testing. It is found that incorporation of deuterium in the doped poly-Si/SiO2/Si interfacial region readily occurs under typical post-metallization sintering conditions, demonstrating that transport of deuterium through CMOS gate is an effective pathway in an encapsulated device structure with silicon nitride sidewalls. The measured Si-D areal densities in the interfacial region depend on gate poly-Si doping type, but in both cases, appear to be sufficient to achieve complete interface Si dangling bond (˜1012 cm−2) passivation for the SiO2-Si system.
Interaction of Deuterium with the Simox Oxide
Authors: Zimmerman L. , Riveral A. , De Nijs J. M. M. , Van Veen A. 
Published: April 2011

ABSTRACTThe interaction of deuterium with silicon-implanted-with-oxygen (SIMOX) was studied for samples with and without silicon top layer using thermal desorption measurements. Deuterium is incorporated in the buried oxide by disruption of the Si-O bridging bonds. The data reveal that the top layer reduces the uptake at 1073K. Furthermore, it retards release; a moderate (≈125K) and a high-temperature (≈1400K) retention were observed. It is proposed that release is accompanied by the reconstruction of the Si-O bonds and that the bare oxide surface constitutes an abundant source for defects thus enhancing the generation and elimination of Si-O bridging bond defects.
Hydrogen Passivation and Ozone Oxidation of Silicon Surface
Authors: Kurokawa Akira , Nakamura Ken , Ichimura Shingo 
Published: April 2011

ABSTRACTThe oxidation of H/Si(100) and H/Si(111) with high concentration ozone gas was investigated with X-ray photoelectron spectroscopy(XPS). The ozone oxidation of partially hydride-covered surface was observed. The hydrogen termination reduced the rate of oxygen insertion into silicon backbond. The reduction of oxygen insertion rate by the H-termination for H/Si(100) was larger than that for HSi(111). The dissociation rate of ozone molecule on H/Si was estimated to be ≃0.2 with a directional mass analyzer.
Infrared Spectroscopy of Sub-Surface Defects induced by Remote Hydrogen Plasma exposure of Silicon(100)
Authors: Lamb H. H. , Bedge S. G. , Wan Z. 
Published: April 2011

ABSTRACTInfrared multiple internal reflection (MIR) spectroscopy was used to investigate the local chemical bonding in sub-surface defects induced by remote hydrogen plasma exposure (RHPE) of Si(100) wafers. Exposure of very lightly doped n-type Si ([P] =; 5 × 1013 cm−3) to a remote hydrogen plasma for 2 min at 200°C results in the formation of Si monohydride species. An intense narrow band at 2078 cm−1 (FWHM = 7 cm−1) and a small shoulder at 2065 cm−1 are observed. The data are consistent with monohydride termination of Si{111} platelet defects with a weak interaction between H atoms on opposing internal surfaces. In contrast, platelet nucleation at 200°C followed by growth at 300°C selectively generates Si dihydride species, as evidenced by a single broad infrared band at 2109 cm−1. The P concentration was found to have a marked influence on the areal density and chemical bonding of sub-surface hydrogen. The MIR spectrum of lightly doped Si ([P] = 2 × 1014 cm−3) after RHPE at 200°C contains broad peaks at 2078 and 2130 cm−1 consistent with Si monohydride and trihydride species. We infer that hydrogen saturates broken bonds along Si{111} Type I glide planes (one bond per Si atom) and along Si{111} Type II glide planes (three bonds per Si atom). The Si-H peak area indicates a H areal density ∼2 times higher than in very lightly doped Si.
Theory of Hydrogen in Semiconductors
Authors: van de walle Chris G. 
Published: April 2011

ABSTRACTThis paper treats the subject of hydrogen in semiconductors from various perspectives. First, a brief historical overview is given. Then, some basic principles governing the interaction between hydrogen and semiconductors are outlined. Finally, specific examples will emphasize the impact of hydrogen on technological applications. While the general treatment applies to interactions of hydrogen with any semiconductor, the applications will focus mainly on hydrogen interacting with silicon.
Effect of Helium on the Electronic Structure of Palladium Tritide
Authors: Gupta R. P. , Gupta M. 
Published: April 2011

ABSTRACTTritium is usually stored in the form of a metal tritide since it is safe to handle in this form, easily recoverable, and further large quantities of tritium can be stored. However, since tritium is radioactive it decays into 3He and an electron. Helium recoil energy in this reaction is very small, and not enough to create defects. We have performed ab-initio electronic structure calculations that show that in PdT, a considerable amount of 3He can be accommodated at the 3He results in an overall enhancement in the strength of the metal- tritium bonding that leads to the lowering of the plateau pressure. We also find that there is a weakening of the metal-metal bonds due to the repulsive interaction with 3He.
Hydrogen Solubility in Inhomogeneous PD Alloys
Authors: Flanagan Ted B. , Wang D. , Clewley J. D. 
Published: April 2011

ABSTRACTAs-cast, arc-melted Pd-Ni alloys are inhomogeneous and the H2 isotherms for these differ from their homogeneous counterparts in the two phase, (dilute + hydride), regions but not in the dilute phase regions. Pd-Ni alloys, which become inhomogeneous via a ternary (Pd + Ni + H) equilibrium phase change, have H2 isotherms which differ from those of the homogeneous alloy in both the two-phase and the dilute phase regions. These results are discussed with respect to the expected type of inhomogeneities.
Microstructure and Lifetime Study of Al/Y Films
Authors: Vedula L. , Pillai V. , Nimmagadda V. S. , Singh R. , Poole K. F. , Gao H. , Pennycook S. J. 
Published: April 2011

ABSTRACTThin Al films alloyed with three different compositions (0.1%, 1%, 5% by weight) of Yttrium were deposited by D.C. Magnetron Sputtering onto oxidized Si wafer substrates. The samples were furnace annealed at 425 °C for 30 minutes. Resistivity measured for the as-deposited and annealed Al(0. lwt% Y) were 3.07 and 2.57+/−0.25 μΩcm respectively. Al(0. lwt% Y) was also annealed by furnace annealing (FA), rapid thermal annealing (RTA) and rapid photothermal annealing (RPA). RPA gave a residual resistivity of 2.67μΩcm in 5 minutes and at a temperature of 350 C for Al(0. lwt% Y). Mean time to failure for AI(0. lwt% Y) samples at a current density of 3.2+/−0.5×106A/cm2 at 30 C was 50 hours. TEM results showed grain size variation from 0.5 to 2 μm.
A Novel Low Temperature Self-Aligned Ti Silicide Technology for Sub-0.18 μm CMOS Devices
Authors: Ren L. P. , Liu P. , Pan G. Z. , Woo Jason C. S. 
Published: April 2011

ABSTRACTA novel low temperature self-aligned Ti silicidation with Ge+ pre-amorphization implant (PAI) is presented. Compared to conventional high temperature PAI silicidation, the advantages of Ti salicidation at temperatures below the recrystallization of a pre-amorphized layer are: (1) C49 TiSi2 silicide formation occurs only in the pre-amorphized layer so that the silicide depth can be well controlled, forming a very sharp interface between the silicide and the Si substrate; (2) Ti just reacts with the amorphous layer, avoiding the so-called bridging issue in which the silicide grows laterally over the isolation or spacer; (3) the effects of metal thickness and substrate doping on silicide formation are suppressed.
Copper Electroplating for Damascene ULSI Interconnects
Authors: Dubin V. M. , Lopatin S. , Chen S. , Cheung R. , Ryu C. , Wong S. S. 
Published: April 2011

ABSTRACTCopper was electroplated on sputtered Cu seed layer with Ta diffusion barrier. We achieved enhanced Cu deposition at the bottom of trenches/vias and defect-free filling sub-0.5 μm trenches (down to 0.25 μm width) of high aspect ratio (up to 4:1). Large grains occupying the entire trench were observed. Bottom step coverage of electroplated copper in sub-0.5 μm trenches was estimated to be about 140%, while sidewalls step coverage was about 120%. Via resistance for sub-0.5 μm vias was measured to be below 0.55 Ω. Strong <111> texture, large grains, and low tensile stress were observed in electroplated Cu films and in-laid Cu lines after low temperature anneal.
Extendibility of Cu Damascene to 0.1 μm Wide Interconnections
Authors: Hu C-K. , Lee K. Y. , Gignac L. , Rossnagel S. M. , Uzoh C. , Chan K. , Roper P. , Harper J. M. E. 
Published: April 2011

ABSTRACTWe demonstrate the extendibility of the Cu damascene process to 0.1 μm wide lines. Cu interconnects, 0.1 - 1 μm wide, were fabricated by a damascene process that produced planarized lines and vias, imbedded in insulators. This process was defined by 1) trench and via formation in blanket dielectrics using e-beam lithography and reactive ion etching, 2) trench fill using a series of metal depositions, and 3) chemical mechanical polishing to remove the field metals. Physical vapor and ionized physical vapor deposition techniques were used to deposit the adhesion/diffusion barrier liner and the Cu seed layer, respectively. The main Cu conductor was deposited by an electroplating method. The width of lines and vias were varied from 0.1 μm to 1 μm while the thicknesses were held constant at 0.45 μm. A near bamboo-like structure was observed in the sub-μm wide lines. The effective resistivity of the Cu lines was found to be about 2.3 μΩ-cm and was independent of width after annealing at 400 °C.
Microstructure and Texture of Electroplated Copper in Damascene Structures
Authors: Gross M. E. , Lingk C. , Siegrist T. , Coleman E. , Brown W. L. , Ueno K. , Tsuchiya Y. , Itoh N. , Ritzdorf T. , Turner J. , Gibbons K. , Klawuhn E. , Biberger M. , Lai W. Y. C. , Miner J. F. , Wu G. , Zhang F. 
Published: April 2011

ABSTRACTThe transition from Al to Cu for advanced ULSI interconnects involves changes in architecture and deposition technique that will influence the microstructure and texture of the metal. Cu interconnects are typically formed within the confines of pre-patterned trenches and vias using an electroplating process with a sputtered Cu conduction layer deposited over a refractory metalbased diffusion barrier layer. In this paper, we focus on the influence of the barrier layer (PVD Ti/TiN, Ta, TaN, CVD TiN) and the effect of a vacuum break between barrier and conduction layer depositions, on the texture of the Cu lines, as examined by X-ray diffraction pole figure analysis.A preferred (111) orientation was observed for all samples. The samples with no vacuum break between barrier and conduction layer deposition exhibited in plane anisotropy that was particularly pronounced for the Ta and TaN samples compared with the Ti/TiN sample. Focused ion beam images and transmission electron micrographs showed Cu grain size to be on the order of the trench width with a high degree of twinning, and no boundary could be distinguished between the PVD Cu conduction layer and the electroplated Cu.
Mocvd of Copper from the Solution of New and Liquid Precursor (hfac)Cu(1-pentene)
Authors: Shin H.-K. , Cho Y.-H. , Yoo D.-J. , Shin H.-J. , Lee E.-S. 
Published: April 2011

ABSTRACTIn an attempt to increase the deposition rate, new Cu (I) compounds, (hfac)Cu(1-pentene)(1) and (hfac)Cu(VTMOS)(2) have been synthesized. These species are chartreuse liquids and exhibit sufficient vapor pressures to allow high transport rates.In order to avoid the premature decomposition of the copper precursors during CVD processes, the 50% of free 1-pentene, and VTMOS was added to the compounds 1 and 2 respectively. These mixtures 1 and 2 were used in this study. Approximately 2gm of precursor was used for each experiment. No premature decomposition of the precursor in the source reservoir was observed during CVD processes. It is a sufficiently important result to expect the use of these mixtures in copper CVD to achieve the reproducible deposition.The copper films using these mixtures were deposited in a hot-wall pyrex reactor at a pressure of approximately 10–2 torr under dynamic vacuum. The films deposited at 100°C, 150°C and 200°C from the mixture 1. Pure copper films were deposited from these species. The resistivities 1.8 ∼ 2.1 μΩcm were obtained in the deposition temperature range. SEM revealed that the surface morphology of the films grown in these depositon temperature range was composed of dense film and grains were well connected. The deposition rate at 200°C was 3,500 Å/min.
Sensitive Analysis of Deposition Chemistry of Cu From (Hfac)Cu(Tmvs) Using Well Characterized Test Structure
Authors: Chae Y. K. , Shimogaki Y. , Komiyama H. 
Published: April 2011

ABSTRACTThe chemistry of Cu-CVD from the precursor (hfac)Cu(tmvs) on sputtered TiN films was investigated using a simple tubular reactor analysis. In the present study, the validity of a proposed reaction mechanism and its rate constants were investigated using a well characterized test structure (Macrocavity). The macrocavity was prepared by stacking silicon wafers with spacing ranging from 0.1–0.5mm, and placing the stacked structure in the tubular reactor. The growth rate profile within a macrocavity is simulated from a derived equation using the reaction mechanism and rate constants obtained from previous work. The variation of the absolute growth rate around the center of a macrocavity with varying wafer spacing indicates that the Cu deposition is proceeded via gas phase reaction to produce a reaction intermediate. As a whole, the simulated growth rate profiles agree very well the experimental data. Therefore, we conclude that the mechanism and reaction rate constants from our research are valid and can be applied to the prediction of growth rate of Cu from the (hfac)Cu(tmvs) system.
Pre-Treatment Effect on Aluminum Thin Films Deposition from Cvd Using Dimethylethylamine Alane
Authors: Jang Tae Woong , Rhee Hwa Sung , Ahn Byung Tae 
Published: April 2011

ABSTRACTTo study the effect of pre-treatment of substrates on the deposition behavior of Al films, the surfaces of TiN and SiO2 substrates were exposed to hydrogen plasma or Ar plasma before Al deposition. The Al films were deposited by the pyrolysis of dimethylethylamine alane (DMEAA). A uniform Al film was deposited by the hydrogen plasma exposure of SiO2 substrate, while island grains were grown by the Ar plasma exposure. The pre-treatments of TiN substrate did not affect the deposition rate of Al film. The concentration of OH radicals at the SiO2 surface was increased by the hydrogen plasma treatment. We suggest that the OH radicals enhance the adsorption of DMEAA on SiO2 surface, resulting in the larger number of nucleation sites.
Ion Beam Induced Metallorganic Chemical Vapor Deposition of Titanium Nitride Films as a Diffusion Barrier Between Cu and Si
Authors: Park Ki-Chul , Kim Soo-Hyun , Kim Ki-Bum 
Published: April 2011

ABSTRACTWe have deposited TiN films by using ion-beam-induced chemical-vapor-deposition (IBICVD). Tetrakis-dimethyl-amido-titanium (TDMAT) was used as a precursor. N2 and Ar gas were used to generate the plasma and the ions in the plasma were extracted by using two electrically isolated grids. The energy of ion beam was about 115–127 eV. The use of N-ion beam significantly lowers the resistivity and carbon content of TiN film (∼320 μΩ-cm, 15 at.%), compared with the thermally decomposed film (∼6000 μΩ-cm, 36 at.%). The use of Ar ion beam also considerably lowers the resistivity of films (∼800 μΩ-cm), but does not reduce the carbon content. The step coverage of the thermally-decomposed film was about 70 %, while the step coverages of the films deposited using N2 and Ar ion beams were about 0 and 30 %, respectively, in 0.5 μm x 1.5 μm contacts. The etch-pit test showed that 50-nm-thick films deposited by using N2 and Ar ion beams prevent the diffusion of Cu into the Si substrate up to annealings at 550 °C and 600 °C for 1 hour, while the thermally decomposed film fails at 500 °C.