bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Hydrogen plasma on electrical and optical properties of transparent conductive oxides.
Authors: Raniero L. , Gonçalves A. , Pimentel A. , Ferreira I. , Zhang S. , Pereira L. , Águas H. , Fortunato E. , Martins R. 
Published: June 2019

AbstractIn this work we study the optical and electrical behavior of ZnO:Ga, ITO and IZO films deposited on glass after sustaining different hydrogen plasma conditions and exposure times. This work was complemented by analyzing the surface morphology of the set of films, which allow us to determine the role of hydrogen plasma on the film's properties such as Hall mobility, free carrier concentration, sheet resistance, optical transmittance, figure of merit and state of the surface. Apart from that, the performances of solar cells using an intrinsic layer constituted by nanocrystalline silicon will be also presented. The data show that the electrical properties of solar cells were improved by using ZnO:Ga as front contact, allowing a high current density collection and single pin solar cells with efficiencies exceeding 11%.
Growth Chemistry of Nanocrystalline Si:H Films
Authors: Dalal Vikram L. , Muthukrishnan Kamal , Stieler Daniel , Noack Max 
Published: June 2019

AbstractWe report on the growth of nanocrystalline Si:H films using both plasma CVD and remote hot wire deposition under systematically varied growth conditions. The films were grown from mixtures of silane and hydrogen. It was found that when the films were grown under low pressure VHF plasma growth conditions, the orientation of the film changed as the pressure increased. At the lowest pressures, the films were mainly <111> oriented, but changed to <220> orientation as the pressure increased. The grain size increased as the growth temperature increased. When the films were grown using remote hot wire deposition, the orientation depended upon both hydrogen dilution and growth temperature. As the hydrogen dilution increased, the <220> grain size became smaller. Grain size as large as 36 nm was obtained by controlling the growth conditions in hot wire deposition. As the growth temperature increased, the size of <220> grains increased. Growth rates also increased with increasing temperature. The data can be explained by invoking a growth model which recognizes that the natural growth direction for Si is <220>, since the surface energy is highest for (220) plane. Random nucleation leads to <220> grains. Bonded H is believed to inhibit the growth of <220> grains.
Metal Induced Growth of Poly-Si Solar Cells and Silicide Nanowires by use of Multiple Catalyst Layers
Authors: Kim Joondong , Ji Chunhai , Anderson Wayne A. 
Published: June 2019

AbstractPolycrystalline Si thin films and single NiSi crystalline nanowires were made by the metal induced growth method. The different growth mechanisms for poly-Si and nanowires lie in the metal silicide formation. Poly-Si growth is based on metal disilicide formation and the growth of nanowires depends on metal monosilicide formation. The metal silicide formation depends on catalyst species and sputtering power. Following catalyst coating, Si was deposited in a DC magnetron sputtering system to grow poly-Si or nanowires. Several metals (Ni, Co, Co/Ni and Pd) were used as catalysts to confirm the nanowire growth mechanism as well as to fabricate solar cells. Poly-Si thin films were about 5 μm thick with up to 1 μm crystallite size. Nanowires were up to 10 μm long with about 50 nm diameter.
Annealing characteristics of Al-doped hydrogenated microcrystalline cubic silicon carbide films
Authors: Miyajima S. , Yamada A. , Konagai M. 
Published: June 2019

AbstractAluminum-doped hydrogenated microcrystalline cubic silicon carbide (μc-3C-SiC:H) films deposited by the hot wire chemical vapor deposition technique at a low substrate temperature of about 300 °C were annealed at various temperatures in vacuum atmosphere. The increase in conductivity was observed on annealing the films over 400°C. The onset of hydrogen desorption occurred in the undoped films at about 650°C, while the onset was shifted towards lower temperatures in the case of Al-doped films. These results indicate that hydrogen plays an important role on the conductivity of the Al-doped μc-3C-SiC:H films.
High-Yield Synthesis of Luminescent Silicon Quantum Dots in a Continuous Flow Nonthermal Plasma Reactor
Authors: Mangolini L. , Thimsen E. , Kortshagen U. 
Published: June 2019

AbstractLight-emission from silicon based on quantum confinement in nanoscale structures has sparked intense research into this field ever since its discovery about 15 years ago. The lack of a simple high-yield synthesis approach for luminescent silicon nanocrystals has so far hampered their widespread application in such diverse areas as opto-electronics, solid-state lighting for general illumination, and fluorescent agents for biological applications. In this paper we discuss a nonthermal plasma process for the synthesis of luminescent silicon nanocrystals. The particle size is mainly controlled by the residence time in the plasma region. The system is capable of producing several tens of milligrams of luminescent powder per hour.
TCAD Modeling of Metal Induced Lateral Crystallization of Amorphous Silicon
Authors: Agapov Aleksey M. , Kalinin Valeri V. , Myasnikov Alexandre M. , Poon Vincent M.C. , Vermeire Bert 
Published: June 2019

AbstractIn our previous publications [1, 2] nickel diffusion and spreading resistance probe (SRP) measurements for quality control of metal induced lateral crystallization (MILC) of amorphous silicon (a-Si) were studied. Now we present TCAD modeling and an explanation of experimental results. By using ISE TCAD the Ni concentration distributions were calculated and compared with results obtained by experiments using SIMS analysis.
Morphology Change, Size Distribution, and Nano-sized Channels in Cu6Sn5 Intermetallic Compound Formation at the SnPb Solder and Copper Interface
Authors: Suh J. O. , Tu K. N. , Gusak A. M. 
Published: June 2019

AbstractThe growth and size distribution of scallop-type Cu6Sn5 intermetallic compound (IMC) at the interface between molten SnPb solder and Cu was investigated, along with a systematic study of morphology change of Cu6Sn5 morphology change as a function of SnPb solder composition. When SnPb solder composition was changed from eutectic (63Sn37Pb) to about 40Sn60Pb, Cu6Sn5 with round scallop-type morphology was found. In other compositions, the Cu6Sn5 scallops showed faceted scallop-type morphology. This morphological change is due to variation of interfacial energy between Cu6Sn5 and solder with a change of solder composition. The growth rate of Cu6Sn5 layer was proportional to cube root of time, and size distribution was in good agreement with the Flux-Driven-Ripening (FDR) theory. The pre-exponent factor k obtained by the measurement was 2.10×10-14 cm3/sec. Based on the k value, the calculated channel width with was about 2 nm, which was in good agreement with experimental observation by transmission electron microscopy.
Ultra low κ PECVD Porogen Approach: Matrix Precursors Comparison and Porogen Removal Treatment Study
Authors: Favennec L. , Jousseaume V. , Rouessac V. , Durand J. , Passemard G. 
Published: June 2019

AbstractThe introduction of new dielectrics into silicon chip interconnection technology is necessary to increase electrical performance. Sub-65nm technologies need κ values below 2.5 and the main way to reduce the dielectric constant is to introduce porosity. This work reports results concerning a two steps PECVD porogen approach to perform Ultra Low κ (κ <2.5). The first step is an hybrid material deposition: i.e. an a-SiOC:H matrix containing organic sacrificial inclusions (porogen phase). In the second step, the porogen is removed by a suitable curing to generate porosity. Two siloxane precursors (decamethylcyclopentasiloxane and diethoxymethylsilane) were evaluated as matrix precursors. Their influences, as well as O2 addition in plasma gas feed, in terms of cross-linking and incorporation were evaluated by FTIR analysis. Thermal anneal and UV treatment (thermally assisted) were evaluated as a curing second step. It allows to better understand this critical step which combines porogen removal and material cross-linking. By optimizing deposition and curing parameters, κ value lower than 2.4 were obtained.
Constraint Effects on Cohesive Failures in Low-k Dielectric Thin Films
Authors: Tsui Ting Y. , McKerrow Andrew J. , Vlassak Joost J. 
Published: June 2019

AbstractOne of the most common forms of cohesive failure observed in brittle thin films subjected to a tensile residual stress is channel cracking, a fracture mode in which through-film cracks propagate in the film. The crack growth rate depends on intrinsic film properties, residual stress, the presence of reactive species in the environment, and the precise film stack. In this paper, we investigate the effect of various buffer layers sandwiched between a brittle carbon-doped-silicate (CDS) film and a silicon substrate on channel cracking of the CDS film. The results show that channel cracking is enhanced if the buffer layer is more compliant than the silicon substrate. Crack velocity increases with increasing buffer layer thickness and decreasing buffer layer stiffness. This is caused by a reduction of the constraint imposed by the substrate on the film and a commensurate increase in energy release rate. The degree of constraint is characterized experimentally as a function of buffer layer thickness and stiffness, and compared to the results of a simple shear lag model that was proposed previously.
Plasma-assisted Atomic Layer Deposition of TiN Films at low Deposition Temperature for High-aspect Ratio Applications
Authors: Heil S.B.S. , Langereis E. , Roozeboom F. , Kemmeren A. , Pham N.P. , Sarro P.M. , van de Sanden M.C.M. , Kessels W.M.M. 
Published: June 2019

AbstractA plasma-assisted atomic layer deposition (PA-ALD) process of titanium nitride (TiN) using TiCl4 precursor dosing and H2/N2 plasma exposure is presented. In situ spectroscopic ellipsometry revealed a growth rate at 400 °C of ∼0.7 A/cycle independent of precursor dosing. Varying the plasma exposure time changed the stoichiometry [N]/[Ti] of the films within the range ∼0.93-1.15. At 100 °C a relatively low chlorine impurity level (∼2 at. %) and low resistivity (∼200 νΔcm) were obtained for a ∼45 nm thick film. The growth rate was found to be considerably lower (∼0.3 Å/cycle) at this temperature. Using TEM imaging we found that PAALD TiN films can be deposited conformally in 20:1 aspect-ratio features (1.5 Êm width) but that the step coverage still needs to be improved, probably by a prolonged plasma exposure step.
CVD Boron Carbo-Nitride as Pore Sealant for Ultra Low-K Interlayer Dielectrics
Authors: Fitzpatrick P. Ryan , Satyanarayana Sri , Sun Yangming , White John M. , Ekerdt John G. 
Published: June 2019

AbstractBlanket porous methyl silsesquioxane (pMSQ) films on a Si substrate were studied with the intent to seal the pores and prevent penetration of a metallic precursor during barrier deposition. The blanket pMSQ films studied were approximately 220 nm thick and had been etched and ashed. When tantalum pentafluoride (TaF5) is exposed to an unsealed pMSQ sample, X-ray photoelectron spectroscopy (XPS) depth profiling and secondary ion mass spectroscopy (SIMS) depth profiling reveal penetration of Ta into the pores all the way to the pMSQ / Si interface. Boron carbo-nitride films were grown by thermal chemical vapor deposition (CVD) using dimethylamine borane (DMAB) precursor with Ar carrier gas and C2H4 coreactant. These films had a stoichiometry of BC0.9N0.07 and have been shown in a previous study to have a k value as low as 3.8. BC0.9N0.07 films ranging from 1.8 to 40.6 nm were deposited on pMSQ and then exposed to TaF5 gas to determine the extent of Ta penetration into the pMSQ. Ta penetration was determined by XPS depth profiling and sometimes SIMS depth profiling. XPS depth profiling of a TaF5 / 6.3 nm BC0.9N0.07 / pMSQ / Si film stack indicates the attenuation of the Ta signal to < 2 at. % throughout the pMSQ. Backside SIMS of this sample suggests that trace amounts of Ta (< 2 at. %) are due to knock-in by Ar ions used for sputtering. An identical film stack containing 3.9 nm BC0.9N0.07 was also successful at inhibiting Ta penetration even with a 370°C post-TaF5 exposure anneal, suggesting the stability of BC0.9N0.07 to thermal diffusion of Ta. All BC0.9N0.07 films thicker than and including 3.9 nm prevented Ta from penetrating into the pMSQ.
Analysis of the Interfacial Reaction Between Sn-3.5Ag and Electroplating Interlayers
Authors: Yang S.M. , Chang Y.Y. , Wu Weite 
Published: June 2019

AbstractAt present, Pb-free process is imperative in the electronic packaging industry. Many reports focus on Pb-free solder to improve the solderability, it seems not obtain wettability as good as SnPb solder. In this study, an alloy interlayer with different content was deposited on Cu to balance wettability and diffusion barrier in the interface of joint by electroplating process. There are three types of interlayers including Cu, Ni, and SnNi alloy. The interlayer may react with Sn-3.5Ag solder during reflow process. Sn-Ni alloy plating layer is selected to improve wettability and provide diffusion barrier at the same time in soldering process. For interfacial microstructure examination, morphology characterization can be obtained by using scanning electron microscope (SEM) and energy-dispersive x-ray analysis (EDX). The structure of IMC is identified by x-ray diffraction (XRD).
Mesoporous Low Dielectric Poly(silsesquioxane) Thin Films Templated by Various Surfactants
Authors: Hyeon-Lee Jingyu , Seon Jong-Baek , Jung Myungsup , Kim Jongmin 
Published: June 2019

AbstractMesoporous low dielectric poly(silsesquioxane) thin films have been fabricated by templating various surfactants such as cetyltrimethyl ammonium bromide (CTAB) or 4-octylphenol polyethoxylate (OPE) in the silsesquioxane polymer matrix and their properties of the thin films characterized by electrical, mechanical and structural characterization. Depending on the types of the surfactants, mesoporous poly(silsesquioxane) thin films with different porosities have been formed. The dielectric constant (k) of the films depended on the content or porosity of the surfactants. The dielectric constants of ca. 2.2–2.4 were obtained for the films with relative porosities of about 15–30 vol. % to the polymer matrix itself. The elastic modulus of the films showed a dependency on the type, content of the surfactants and was ca. 2.9 GPa with the k value of ca. 2.38.
Fundamentals of Cu/Barrier-Layer Adhesion in Microelectronic Processing
Authors: Simka Harsono , Shankar Sadasivan , Duran Carolyn , Haverty Michael 
Published: June 2019

AbstractCopper is most widely used interconnect material in present silicon microelectronic technologies. As such, multiple interfaces formed by a thin Cu layer and other materials must be engineered to achieve the desired chemical, mechanical, and electrical properties. Adhesion between Cu and the barrier layer, as well as between Cu and the dielectric, is of particular interest, due to its role in controlling interfacial stability and Cu electromigration behavior [1]. This work focuses on understanding how the interface chemistry affects adhesion. Firstprinciples density functional theory (DFT) calculations were used to determine chemical adhesion energies of interfaces formed by Cu and various metals considered as a diffusion barrier, including Ta, TiN, and W. Calculations predicted increasing adhesion strength in the order of TiN < Si-doped TiN < TaN < Ta, consistent with wetting experiments done using 100Å thick Cu layer samples. The effects of doping at the interface using light elements (C, N, O) were also determined. Calculations were also done for interfaces of Cu with two different classes of amorphous dielectric materials, i.e. silicon nitride and silicon carbide, for which detailed material characterizations are often difficult and time consuming. Calculations predicted Cu/Si-nitride and Cu/Si-carbide adhesion strengths consistent with 4-pt-bend experiments, including the improvement in adhesion energies when silicon was used to dope the interface. In addition, weaker interfaces provide low-resistance diffusion paths for Cu atoms during electromigration. The first-principles based modeling, validated by select adhesion measurements, provides a predictive approach to effectively determine adhesion strengths and predict electromigration reliability in interconnects.
Optimization of the metal/silicon ratio on nickel assisted crystallization of amorphous silicon
Authors: Pereira L. , Beckers M. , Martins R.M.S. , Fortunato E. , Martins R. 
Published: June 2019

AbstractThe aim of this work is to optimize the metal/silicon ratio on nickel metal induced crystallization of silicon. For this purpose amorphous silicon layers with 80, 125 and 220 nm thick were used on the top of which 0.5 nm of Ni was deposited and annealed during the required time to full crystallize the a-Si. The data show that the 80 nm a-Si layer reaches a crystalline fraction of 95.7% (as detected by spectroscopic ellipsometry) after annealed for only 2 hours. No significant structural improvement is detected by ellipsometry neither by XRD when annealing the films for longer times. However, on 125 nm thick samples, after annealing for 2 hours the crystalline fraction is only 59.7%, reaching a similar value to the one with 80 nm only after 5 hours, with a crystalline fraction of 92.2%. Here again no significant improvements were achieved by using longer annealing times. Finally, the 220 nm thick a-Si sample is completely crystallized only after 10 hours annealing. These data clear suggest that the crystallization of thicker a-Si layers requires thicker Ni films to be effective for short annealing times. A direct dependence of the crystallization time on the metal/silicon ratio was observed and estimated.
Co-firing of Low- and Middle Permittivity Dielectric Tapes in Low-Temperature Co-fired Ceramics
Authors: Park Jae-Hwan , Choi Young-Jin , Park Jae-Gwan 
Published: June 2019

AbstractCompatibility in cofiring low-κ and middle-κ based on a same glass composition for the hybrid LTCC material systems was investigated. Designing of appropriate lithium borosilicate glass frit systems allowed us to develop an optimized glass frit system used for low-κ and middle-κ dielectric fillers, commonly. The effects of glass addition on the densification and electrical properties in low-κ and middle-κ dielectric materials were also examined. Controlling glass compositions and contents we tried to match low-κ and middle-κ tapes physically and chemically.
Macroporous Silicon Sensor Arrays for Chemical and Biological Detection
Authors: Clarkson Jeffrey , Rajalingam Vimalan , Hirschman Karl D. , Ouyang Huimin , Sun Wei , Fauchet Philippe M. 
Published: June 2019

AbstractA new class of silicon-based chemical and biological sensors that offer an electrical response to a variety of substances is described. The devices utilize silicon flow-through sensing membranes with deep trench structures formed to depths up to 100μm, fabricated by electrochemical etching which transforms the silicon into macro-porous silicon (MPS). The sensors have demonstrated the ability to detect the presence of certain chemical and biological materials. Although the principle of operation of the devices is fairly complex, the transduction mechanisms can be compared to chemiresistors and chemically sensitive field-effect transistors (chemFETs). The electrical responses that have shown the most sensitivity are AC conductance and capacitance. Previous work has demonstrated that upon exposure to organic solvents (i.e. ethanol, acetone, benzene) the devices exhibit a characteristic impedance signature. The devices have also shown the ability to detect the hybridization of complementary DNA. The incorporation of other materials that have demonstrated sensitivity to low ambient levels of contaminants is also under investigation. The sensors have been designed and fabricated in linear array configurations; a microfluidic transport chip/package co-design is currently in progress.
A Novel Technology to Create Monolithic Instruments for Micro Total Analysis Systems
Authors: Seibel Konstantin , Schöler Lars , Walder Marcus , Schäfer Heiko , Schäfer André , Pletzer Tobias , Püschl René , Waidelich Michael , Ihmels Heiko , Ehrhardt Dietmar , Böhm Markus 
Published: June 2019

AbstractThe feasibility of micro total analysis systems (μTAS) on microchips based on the concept of a monolithic instrument is demonstrated. In such a device a microfluidic layer system is deposited in a backend process on a conventional CMOS integrated circuit with the aim to achieve cost and performance enhancements through integration and miniaturization. Experimental results on elementary functional components of a μTAS are presented including a narrow channel electroosmotic micropump, a micro mass flow meter using the thermal anemometric principle, a micro cytometer with integrated optical detection, and elementary structures for on-chip micro-capillary electrophoresis.
Biosilica Nanofabrication in Diatoms: The Structures and Properties of Regulatory Silaffins
Authors: Kröger Nils , Poulsen Nicole 
Published: June 2019

AbstractDiatoms are a large group of unicellular microalgae encased by silica cell walls that exhibit species-specific, mostly porous micro-and nanopatterns. Previously, from the diatomCylindrotheca fusiformisunique phosphoproteins (termed silaffins) and unusually long polyamine chains (termed LCPA) have been identified and implicated in silica formation. However, analysis of the general role of silaffins in species-specific silica morphogenesis has been hampered by lack of data about silaffins from other diatom species. Recently, we have isolated the five major silaffins from the diatomThalassiosira pseudonanaand aided by the genome data available from this organisms we were able structurally und functionally characterize these molecules. These data clearly support the hypothesis that silaffins play an important role in the nanofabrication of diatom biosilica. The basic insights into the mechanism of biomineral morphogenesis by silaffins and LCPA suggest future pathways for the fabrication of nanostructured minerals by synthetically available polymers.
A High-Throughput Crystallization Device to Study Biomineralization in Vitro
Authors: Becker Alexander , Epple Matthias 
Published: June 2019

AbstractA new crystallization device, based on a constant-composition double-diffusion setup, was constructed to study biomineralization in vitro. The device was tested with poly(aspartic acid) as a model additive in the precipitation of calcium carbonate, showing a complete crystal growth inhibition.
Room-temperature Ferromagnetism in Nanostructured Co-doped ZnO
Authors: Wei M. , Khare N. , Yates K. A. , Zhi D. , MacManus-Driscoll J. L. 
Published: June 2019

AbstractNanosized Co-doped ZnO samples were synthesized using an ultrasonic spray assisted chemical vapour deposition method. Microstructural and magnetic properties of these samples were studied. The room-temperature ferromagnetism was observed in the Co-doped ZnO. Also, x-ray analysis revealed a wurtzite ZnO structure with a small change of the lattice constants due to the doping of Co in ZnO. Raman spectroscopy of the Co-doped ZnO films indicated direct substitution of Co. Scanning electron microscopy showed nanostructured Co-doped ZnO with a ring or cup shape. Transmission electron microscopy analysis revealed nano grains within the rings of an average diameter of around 10 nm. Both energy dispersive spectroscopy and energy-filtered transmission electron microscopy indicated a uniform distribution of Co.