bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactive Pulsed Laser Deposition of Microcrystalline Ge-based Thin Films
Authors: Wills Matthew R. , Shinar Ruth , Constant Alan P. 
Published: June 2019

AbstractPulsed laser deposition (PLD) was used to grow microcrystalline thin films of germanium (Ge) and Ge-carbon (Ge,C) alloys on fused quartz and silicon substrates at substrate temperatures 25°C ≤ Ts ≤ 325°C. The films were analyzed structurally with x-ray diffraction (XRD), optically, electrically with four-point probe measurements, and chemically with x-ray photoelectron spectroscopy (XPS). XRD results displayed a varying degree of crystallinity, with the most crystalline films obtained at Ts > 150°C. The resistivity of the Ge films decreased with increasing temperature, displaying a significant decrease for the films deposited at Ts ≥ 230°C. The growth conditions for Ge films served as a starting point for low-temperature deposition of Ge,C alloys with up to 5% C. The effects of Ts and carbon concentration on film properties are discussed.
High Rate Deposition of Stable Hydrogenated Amorphous Silicon in Transition from Amorphous to Microcrystalline Silicon
Authors: Hou Guofu , Geng Xinhua , Zhang Xiaodan , Zhao Ying , Xue Junming , Ren Huizhi , Sun Jian , Zhang Dekun , Xu Yueqin 
Published: June 2019

AbstractHigh rate deposition of high quality and stable hydrogenated amorphous silicon (a-Si:H) films were performed near the threshold of amorphous to microcrystalline phase transition using a very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) method. The effect of hydrogen dilution on optic-electronic and structural properties of these films was investigated by Fourier-transform infrared (FTIR) spectroscopy, Raman scattering and constant photocurrent method (CPM). Experiment showed that although the phase transition was much influenced by hydrogen dilution, it also strongly depended on substrate temperature, working pressure and plasma power. With optimized condition high quality and high stable a-Si:H films, which exhibit σph/σd of 4.4×106 and deposition rate of 28.8Å/s, have been obtained.
Silicides for the 65 nm Technology Node
Authors: Besser Paul R. , Chan Simon , Paton Eric , Kammler Thorsten , Brown David , King Paul , Pressley Laura 
Published: June 2019

AbstractAt the 65 nm node, silicide faces formidable challenges. Co is the current process of record for most integrated circuit manufacturers and thus becomes baseline silicide for 65 nm. However, Ni is the likely replacement. Both silicides are challenged to meet the requirements at the 65 nm node. This manuscript reviews the current CoSi2challenges (dopant interactions, Ge interactions, linewidth extendibility, impurity effects, agglomeration issues, etc). Ni consumes less Si but has its own challenges, including issues with contact leakage and thermal budget, excessive diffusion and oxidation, interactions with dopant and impurities. Both silicides have formation and stability issues in the presence of Ge. Additions of Ge increase the temperature at which a low resistance CoSi2is formed due to film segregation into CoSi2and Ge-rich Si-Ge grains. With Ni, additions of Ge decrease the temperature at which NiSi converts to a NiSi2, lead to agglomeration at a lower temperature and lead to germanosilicide formation.
Enhancement of Copper Wetting via Surfactant-Based Post-Treatment of Ultra-Thin Atomic Layer Deposited Tantalum Nitride Liners
Authors: Straten Oscar van der , Zhu Yu , Dunn Kathleen , Kaloyeros Alain 
Published: June 2019

AbstractThe influence of surfactant-based liner post-treatment on the wetting and nucleation characteristics of ultra-thin copper (Cu) films has been examined, employing ultra-thin atomic layer deposited (ALD) tantalum nitride (TaNx) as liner material. This surfactant-based posttreatment consists of in-situ exposure of the liner to a metal-organic source containing a low surface free energy metal (Sn) surfactant, which is a potential candidate for enhancing the wetting of Cu on liner surfaces and subsequently suppressing island-type growth of Cu, due to both the high atomic volume and low surface free energy of the surfactant relative to Cu. A methodology involving thermally-enhanced de-wetting of Cu, promoted by annealing Cu/liner stacks in a forming gas (95% Ar, 5% H2) ambient under several applied thermal budgets (annealing at 350°C for 30 minutes, and at 600°C for 4, 12, and 48 hrs, respectively), was utilized to both elucidate and quantify the wetting properties of Cu on liners, via detailed analyses of the surface morphology of annealed stacks by atomic force microscopy (AFM) and scanning electron microscopy (SEM). By comparing stacks containing ALD TaNx liners to those that contain post-treated ALD TaNx liners, this method allowed an evaluation of the effectiveness of surfactant-based liner surface post-treatments in inhibiting Cu de-wetting.
The Integration of Plasma Enhanced Atomic Layer Deposition (PEALD) of Tantalum-Based Thin Films for Copper Diffusion Barrier Applications
Authors: Cheng Degang , Eisenbraun Eric T. 
Published: June 2019

AbstractA plasma-enhanced atomic layer deposition (PEALD) process for the growth of tantalumbased compounds is employed in integration studies for advanced copper metallization on a 200- mm wafer cluster tool platform. This process employs terbutylimido tris(diethylamido)tantalum (TBTDET) as precursor and hydrogen plasma as the reducing agent at a temperature of 250°C. Auger electron spectrometry, X-ray photoelectron spectrometry, and X-ray diffraction analyses indicate that the deposited films are carbide rich, and possess electrical resistivity as low as 250νΔcm, significantly lower than that of tantalum nitride deposited by conventional ALD or CVD using TBTDET and ammonia. PEALD Ta(C)N also possesses a strong resistance to oxidation, and possesses diffusion barrier properties superior to those of thermally grown TaN.
Characterization of Atomic Layer DepositedWNxCy Thin Film as a Diffusion Barrier for CopperMetallization
Authors: Kim Soo-Hyun , Oh Su Suk , Kim Hyun-Mi , Kang Dae-Hwan , Kim Ki-Bum , Li Wei-Min , Haukka Suvi , Tuominen Marko 
Published: June 2019

AbstractThe film properties of WNxCy films deposited by atomic layer deposition (ALD) using WF6, NH3, and triethylboron source gases were characterized as diffusion barrier for Cu metallization. It is noted that the as-deposited film shows an extremely low resistivity of about 350 μΔ-cm with a film density of 15.37 g/cm3. The film composition measured from Rutherford backscattering spectrometry shows W, C, and N of approximately 48, 32, and 20 at.%, respectively. Transmission electron microscopy analyses show that the as-deposited film is composed of face-centered-cubic phase with a lattice parameter similar to both β-WC1-x and β-W2N with an equiaxed microstructure. The barrier property of this ALD-WNxCy film at a nominal thickness of 12 nm deposited between Cu and Si fails only after annealing at 700°C for 30 minutes while the sputter-deposited Ta (12 nm) and ALD-TiN (20 nm) fail at 650 and 600°C, respectively. It is thought that the superior diffusion barrier performance of ALD-WNxCyfilm is the consequence of both nanocrystalline equiaxed grain structure and the formation of high density film.
Grain Boundary Characteristics and Stress-induced Damage Morphologies in Sputtered and Electroplated Copper Films
Authors: Park Hyun , Hwang Soo-Jung , Oh Kyu Hwan , Joo Young-Chang 
Published: June 2019

AbstractVarious Cu films were fabricated using sputtering and electroplating with and without additive, and their surface damages after annealing were investigated. After annealing at 435°C, the difference between damage morphologies of the films was observed. In some films stressinduced grooves along the grain boundaries were observed, while in the others voids at the grain boundary triple junctions were observed. It was also observed that the stress-induced groove was formed along the high energy grain boundaries. To explain the morphological difference of surface damages, a simple parameter considering the contributions of grain structures and grain boundary characteristics to surface and grain boundary diffusions is suggested. The effective grain boundary area, which is a function of grain size, film thickness and the fraction of high energy grain boundaries, played a key role in the morphological difference.
Comparison of the Time-Dependent Physical Processes in the Electromigration of Deep Submicron Copper and Aluminum Interconnects
Authors: Zhang G. , Tan C. M. , Gan Z. H. , Prasad K. , Zhang D. H. 
Published: June 2019

AbstractElectromigration (EM) is a major reliability issue in VLSI. Many physical processes are involved simultaneously in an EM process, namely atom migration due to electron wind force, thermal migration due to temperature gradient, stress migration due to stress gradient, and surface migration (just when free surface is available) due to surface tension. In this work, the intrinsic EM damages of Al and Cu, that is without the effect from the surrounding materials, was investigated and compared based on the finite element analysis (FEA). The FEA results show that, in the intrinsic Al EM damage, electron wind force induced flux divergence is always the main cause of void growth; however, in the intrinsic Cu EM damage, dominant flux divergence varies with time, with the final dominant flux divergence due to electron wind force. It is also found that current density and temperature gradient are the most important factors affecting flux divergence. These simulation predictions agree with experimental observation and theoretical analysis.
Anisotropic Plasma ChemicalVapor Deposition of Copper Films in Trenches
Authors: Takenaka Kosuke , Onishi Masao , Takenshita Manabu , Kinoshita Toshio , Koga Kazunori , Shiratani Masaharu , Watanabe Yukio 
Published: June 2019

AbstractAn ion-assisted chemical vapor deposition method by which Cu is deposited preferentially from the bottom of trenches (anisotropic CVD) has been proposed in order to fill small via holes and trenches. By using Ar + H2 + C2H5OH[Cu(hfac)2] discharges with a ratio H2 / (H2 + Ar) = 83%, Cu is filled preferentially from the bottom of trenches without deposition on the sidewall and top surfaces. The deposition rate on the bottom surface of trenches is experimentally found to increase with decreasing its width.
Afm Studies of Deformation and Interfacial Sliding in Interconnect Structures in Microelectronic Devices
Authors: Park C. , Dutta I. , Peterson K.A. , Vella J. 
Published: June 2019

AbstractBack-end interconnect structures (BEIS) of micro-electronic devices are susceptible to several deformation phenomena during thermal excursions, because of large differences in thermal expansion coefficients (CTE) between Si, interlayer dielectric (ILD) and metal lines. Here we use atomic force microscopy (AFM) to study plastic deformation and interfacial sliding of Cu interconnect lines on embedded in a low K dielectric (LKD). Following thermal cycling, changes were observed in both inplane Cu line dimensions, as well as out-of plane step height between Cu and LKD in single layer structures. The results of AFM measurements following both ex-situ and in-situ thermal cycling presented. A shear-lag based model is utilized to simulate the thermal cycling response, and rationalize the observed interfacial sliding behavior. Results of in-situ AFM experiments to observe the deformation of Cu-low K interconnect structures under far-field (i.e., package-level) stresses are also presented.
High-Frequency Heterodyne Force Microscopy Investigations Of Copper Interconnects
Authors: Zheng Yuegui , Geer Robert 
Published: June 2019

AbstractA nondestructive methodology for characterizing Cu interconnects in integrated circuits (ICs) has long been sought and has motivated significant efforts regarding metrology tool development. Here, we present investigations of high-frequency heterodyne force microscopy (HFM) to investigate the acoustic response of damascene-processed Cu interconnects in a silicon oxide dielectric. HFM is a phase-resolved mechanical imaging technique that can, in principle, measure acoustic phase variations with nanometer spatial resolution. HFM measurements at carrier frequencies of 10.8 MHz and 72.5 MHz reveal phase differences of 0.5°-0.7° and 3.5°-4.5°, respectively, between the SiO2 and Cu regions of the IC test structure. Such phase differences are consistent with expected variations due to acoustic propagation time differentials between the Cu and SiO2 regions. Coupled with detailed mechanical measurements of the Cu and SiO2 regions this data may be used to extract spatial maps of acoustic phase delay and investigate subsurface features of similar IC test structures.
Dielectric GlueWafer Bonding For 3D ICs
Authors: Kwon Y. , Jinda A. , McMahon J.J. , Lu J.Q. , Gutmann R.J. , Cale T.S. 
Published: June 2019

AbstractA process to bond 200 mm wafers for wafer-level three-dimensional integrated circuit (3D-IC) applications is discussed. Four-point bending is used to quantify the bonding strength and identify the weak interface. Using benzocylcobutene (BCB) glue, the bonding strength depends on (1) glue thickness, (2) glue film preparation, and (3) materials and structures on the wafer(s). A seamless BCB-to-BCB bond interface provides the highest bonding strength compared to other interfaces in these structures (> 34 J/m2). Mechanical and electrical properties of a wafer with copper interconnect structures are preserved after wafer bonding and wafer thinning, confirming the potential of the bonding process for 3D ICs.
Plasma Hydrogenation – A New Method of Reducing the k Value of the Low k Polyimide Film
Authors: Kuo Yue , Chung Taewoo , Nominanda Helinda 
Published: June 2019

AbstractA new method of lowering the dielectric constant (k) of a low k polyimide thin film by plasma hydrogenation has been studied. The influence of the plasma process to the material properties, such as the composition, binding energies, and bond types, and dielectric characters, such as k and leakage current, were investigated. The result showed that after hydrogenation, the film's chemical and physical structures were changed. The film's k value could be lowered to 2.3 or less and the leakage current was only slightly increased. The mechanism of the process, which is responsible for the film's material and electrical property changes, is discussed. This is an effective method in preparing dielectrics with very low k values, which is critical for the success of the multilevel interconnection structure.
Indentation Fracture Toughness Measurements of Low Dielectric Constant Materials
Authors: Morris Dylan J. , Cook Robert F. 
Published: June 2019

AbstractThe physics and mechanics of a fracture toughness measurement technique for low-k films are described. It has been observed experimentally that it is possible to generate reproducible stable cracks at indentation sites in thin low-k films using cube-corner indentation. The fracture response depends on the film thickness and follows no simple scaling laws. The physics of a model that takes into account the stress fields from indentation and film stress, with particular attention paid to the Poisson's ratio of the film, are described. The model is able to predict the changes in observables when the film thickness is changed, which allows one to estimate film toughness independent of the configuration of the material.
Controlled Growth of Single-Walled Carbon Nanotubes from a Line Patterned Mesoporous Silica Template
Authors: Huang Limin , Wind Shalom J. , O'Brien Stephen P. 
Published: June 2019

AbstractCarbon nanotubes (CNTs) with controlled orientation and diameter (1-4 nm) were grown from thermally stable, highly ordered mesoporous SiO2 thin films by methane chemical vapor deposition (CVD). Controlled incorporation of Fe precursor into pore channels of the mesoporous SiO2 by a sol-gel process results in a nanostructure catalytically active for CNT growth and stable to typical CVD temperatures. Growth of CNTs starts within the mesoporous SiO2, whose pore direction and pore dimension play an important role in the orientation and diameter of the CNTs at the early stage of the growth. Lateral growth results in a parallel assembly of CNTs with controlled tube dimension from a line-micropatterned mesoporous SiO2 film fabricated by soft-lithography.
Processing of Transparent Polymer Nanotube Composites via Heat, UV Radiation and Ionizing (gamma) Radiation using Ultrasonication and Solvent Dissolution
Authors: Clayton L. M. , Muisener P. A. O'Rourke , Harmon J. P. , Sikder A. K. , Kumar A. , Cassell A. M. , Cinke M. , Meyyappan M. 
Published: June 2019

AbstractPoly (methyl methacrylate)/single walled carbon nanotube (PMMA/SWNT) composites were polymerized in the presence of carbon nanotubes via three methods: heat, uv radiation and ionizing radiation (gamma). Samples were solvent processed and cast into films. Thin films with varying degrees of transparency resulted from these composites. Differential Scanning Calorimetry (DSC) characterized glass transition temperatures. Ultraviolet-visible spectroscopy (UV-VIS) quantified the transparency of composites. The dielectric constant (ε') was obtained from Dielectric Analysis (DEA) and correlated to the refractive index values using Maxwell's Relationship. Scanning Electron Microscopy (SEM) provided images of the polymer- nanotube composite.
Incorporation of Multi Wall Carbon Nanotubes into Glass-Surfaces via Laser-Treatment
Authors: Seeger T. , Fuente G. de la , Maser W.K. , Benito A.M. , Righi A. , Sauvajol J.L. , Martínez M. T. 
Published: June 2019

AbstractCarbon nanotubes (CNT) are interesting candidates for the reinforcement in robust composites and for conducting fillers in polymers due to their fascinating electronic and mechanical properties. For the first time, we report the incorporation of multi walled carbon nanotubes (MWNTs) into silica-glass surfaces by means of partial surface-melting caused by a continuous wave Nd:YAG laser. MWNTs were detected being well incorporated in the silica-surface. The composites are characterized using scanning electron microscopy (SEM) and Raman-spectroscopy. A model for the composite-formation is proposed based on heatabsorption by MWNTs and a partial melting of the silica-surface.
Growth of Multi Walled CNX Nanotubes: The Role of Synthesis Methods
Authors: Castignolles M. , Loiseau A. , Enouz S. , Bernier P. , Glerup M. 
Published: June 2019

AbstractMulti walled nitrogen doped nanotubes were synthesized using two different methods. The growth mechanism and nitrogen concentration of the nanotubes synthesized by both methods are discussed and studied. The morphology and nitrogen concentration of the nanotubes are seen to strongly depend on the synthesis methods. The results are based on detailed high resolution transmission electron microscopy (HRTEM) data coupled with electron energy loss spectroscopy (EELS).
Largest Band Gap of All Single Walled Carbon Nanotubes
Authors: Cabria I. , Mintmire J. W. , White C. T. 
Published: June 2019

AbstractSingle walled carbon nanotubes, SWNTs, are either semiconducting, metallic, or quasimetallic. Early theoretical work based on tight-binding models predicted that the band gap of semiconducting carbon nanotubes should increase with decreasing radius and this picture was later confirmed by experiment. However, local-density functional calculations indicate that these models are not accurate for narrow carbon nanotubes, where the effects of curvature can convert nanotubes expected to be semiconductors to metals. This raises the question, what is the largest semiconducting band gap possible in a SWNT? We present results from first-principles calculations for a range of carbon nanotubes with radii between 0.15 and 1 nm. These results indicate that the (4,3) carbon nanotube has the largest band gap of all SWNTs.
Understanding Noncovalent Absorption and Packing of 1-Pyrene Butanoic Acid Succinimidyl Ester on Single Walled Carbon Nanotubes
Authors: Han Si-Ping , Cagin Tahir , Goddard William A. 
Published: June 2019

AbstractSingle walled carbon nanotubes (SWNT) have unique properties that give them strong potential for applications in high performance sensors and molecular electronics.1 One problem relevant to such technological applications is the functionalization of SWNT sidewalls. Recent experiments at Stanford have shown that 1-pyrene butanoic acid succinimidyl ester (PBSE) shows promise for non-covalent absorption onto SWNT sidewalls. We have conducted studies aimed at understanding the structural arrangement and packing of PBSE on the SWNT sidewall.
Formation and Transistor Behavior of Carbon Nanotube T-junctions
Authors: Chiu Po-Wen , Benoit Jean-Michel , Graupner Ralf , Dettlaff Ursula , Roth Siegmar 
Published: June 2019

AbstractWe present the formation of intermolecular nanotube junctions and investigations of their transistor behavior. T-shape junctions were formed by coupling chemically functionalized nanotubes with molecular linkers. An end-to-side or end-to-end heterojunction can be formed by reacting chloride terminated nanotubes with aliphatic diamine. The chemically modified nanotube mats were characterized by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The incorporation of functional groups into nanotubes are first identified by XPS. The carbon binding energy shifts due to the doping effect by attached functional groups. This also leads to a pronounced shift of tangential vibration modes in Raman spectra. To investigate the electrical transport, functionalized nanotubes were deposited on Si substrates, and metal contacts were applied on top of the selected T-shape junctions. The bar of the “T” is used as a transistor channel and the leg of the “T” is used as a gate. In this configuration, the active area is confined to a few nanometers in all three dimensions and gain values of 100 and above are obtained.
Investigation of the Surface Stress in SiC Nanocrystals by In-situ High Pressure Powder Diffraction Technique
Authors: Palosz B. , Stel'makh S. , Grzanka E. , Gierlotka S. , Zhao Y. , Palosz W. 
Published: June 2019

AbstractThe properties of nanocrystals were studied by in-situ high-pressure powder diffraction technique using our methodology of the structural analysis, the “apparent lattice parameter” (alp) concept. The experiments were performed for nanocrystalline SiC and diamond powders using synchrotron and neutron sources and hydrostatic or isostatic pressure. Elastic properties of the samples were examined based on the measurements of the lattice parameters and of the reflection width, as well as of interatomic distances. The results show a dual nature of the properties (compressibilities) of the powders indicating a complex, core-shell structure of the grains.
Creep Behaviour of a Crystallized Si-B-C-N Ceramic Obtained from the Polymeric Precursor T2-1(B[C2H4Si(CH3)NH]3)n
Authors: Kumar N.V. Ravi , Zimmermann André , Aldinger Fritz 
Published: June 2019

AbstractThe boron modified poly(vinyl)silazane polymer precursor with the chemical composition (B[C2H4Si(CH3)NH]3)n was milled and sieved. The polymer particles from different size fractions were compacted using a graphite die in a uni-axial warm pressing machine at a pressure of 48 MPa and in the temperature range 250°C to 330°C. The green bodies were pyrolysed in an argon atmosphere at a temperature of 1300°C when the organic polymer converts into an inorganic amorphous Si-B-C-N ceramic. These amorphous ceramics were annealed under various conditions of temperature, nitrogen overpressure and holding time in order to crystallize them and to produce nano-crystalline microstructures. Compression creep experiments were carried out in atmospheric ambience at loads varying from 5 – 100 MPa and in the temperature range 1350°C – 1500°C to investigate the high temperature deformation behaviour of the crystalline material. The interest is to understand the mechanisms of deformation in these nanocrystalline Si-B-C-N ceramics at elevated temperatures and to compare the results with that of amorphous ceramics. The investigation also includes the determination of viscosity of the material at high temperatures.