bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new model for Boron diffusion retardation in SiGe-strained layers accounting for the mechanism of Boron trapping/detrapping by Ge atoms.
Authors: Kol'dyaev Victor I. 
Published: April 2011

ABSTRACTThe main drawbacks of the known models of the B diffusion in strained SiGe layers are summarized. A mechanism is suggested to self-consistently explain the main experimental features and original experimental data which considers the trapping of B atoms by Ge atoms during B diffusion in the Si lattice resulting in the retarded B diffusivity. Fluctuations of Ge atom numbers in a nearest B atom environment result in percolation mechanism of B transport through dilatation centers of random size. A new solid state transport modelis generalized by considering dispersion transport of positive and negative point dilatation defects.
Phosphorus diffusion in silicon; influence of annealing conditions
Authors: Christensen J. S. , Kuznetsov A. Yu. , Radamson H. H. , Svensson B. G. 
Published: April 2011

ABSTRACTPhosphorus diffusion has been studied in both pure epitaxially grown silicon and Cz silicon, with a substantial amount of impurities like oxygen and carbon. Anneals have been performed in different atmospheres, N2 and dry O2, as well as in vacuum, at temperatures between 810 – 1100°C. Diffusion coefficients extracted from these anneals show no difference for the P diffusion in the epitaxially grown or the Cz silicon. The diffusion coefficients follow an Arrhenius dependence with the activation energy Ea=2.74±0.07 eV and a prefactor D0 = (8±5)×10−4 cm2/s. These parameters differ considerably from the previously reported and widely accepted values (3.66 eV and 3.84 cm2/s, respectively). However, vacuum anneals of the same samplesresult in values close to this 3.6 eV diffusion mode. Furthermore, control anneals of boron doped samples, with similar design as the phosphorus samples, suggest the same trend for boron diffusion in silicon – lower versus higher values of activation energies for nitrogen and vacuum anneals, respectively. These results are discussed in terms of the concentration of Si self-interstitials mediating the diffusion of phosphorus and boron.
Modeling Threading Dislocation Loop Nucleation and Evolution in MeV Boron Implanted Silicon
Authors: Avci Ibrahim , Law Mark E. , Jasper Craig , Rueda Hernan A. , Thoma Rainer 
Published: April 2011

ABSTRACTA single statistical point defect based model for the nucleation and evolution of dislocation loops during annealing in Si is developed. The model assumes that the radius and the density of dislocation loops follow a log normal distribution. The loop nucleation part of the model also assumes that all the loops come from {311} unfaulting. The model is verified with the experimental results obtained by studying the formation of dislocation loops and threading dislocation loops as a function of implant condition in boron implanted silicon by varying the dose from 1×1013 to 5×1014 cm−2 at an energy of 1.5 MeV. Due to the statistical nature of the model, the threading dislocation loop density is easily obtained from simulation results. The dramatic change in the threading dislocation loop density withthe increasing implant dose is also predicted by the simulations.
Diffusion and Defect Structure in Nitrogen Implanted Silicon
Authors: Dokumaci Omer , Kaplan Richard , Khare Mukesh , Ronsheim Paul , Burnham Jay , Domenicucci Anthony , Li Jinghong , Fleming Robert , Adam Lahir S. , Law Mark E. 
Published: April 2011

ABSTRACTNitrogen diffusion and defect structure were investigated after medium to high dose nitrogen implantation and anneal. 11 keV N2+ was implanted into silicon at doses ranging from 2×1014 to 2×1015 cm−2. The samples were annealed with an RTA system from 750°C to 900°C in a nitrogen atmosphere or at 1000°C in an oxidizing ambient. Nitrogen profiles were obtained by SIMS, and cross-section TEM was done on selected samples. TOF-SIMS was carried out in the oxidized samples. For lower doses, most of the nitrogen diffuses out of silicon into the silicon/oxide interface as expected. For the highest dose, a significant portion of the nitrogen still remains in silicon even after the highest thermal budget. This is attributed to the finite capacity of the silicon/oxide interface to trap nitrogen. When the interface gets saturated by nitrogen atoms, nitrogen in silicon can not escape into the interface. Implant doses above 7×1014 create continuous amorphous layers from the surface. For the 2×1015 case, there is residual amorphous silicon at the surface even after a 750°C 2 min anneal. After the 900°C 2 min anneal, the silicon fully recrystallizes leaving behind stacking faults at the surface and residual end of range damage.
Modeling Boron and Indium Electrical Activities in Silicon in the Presence of Nitrogen
Authors: Zubkov Vladimir , Aronowitz Sheldon , Puchner Helmut , Senosiain Juan P. 
Published: April 2011

ABSTRACTThe ab initio pseudopotential code (VASP) was employed to explore indium and boron electrical activities in silicon in the presence of nitrogen. Electrical activities for the combinations B+N, In+N, and In+B+N were explored. Formation energy of a negatively charged supercell, (E−)f, and a band gap, Eg, from calculations with one k point were chosen as indicators of acceptor activity. For separate dopants the calculated (E−)f and Eg values indicate that substitutional B and In are effective acceptors and N is an extremely weak donor. When nitrogen is adjacent to, or separated 3 - 5 bonds from B or In, it suppresses acceptor activity. Binding is greater for In+N than for B+N in agreement with secondary ion mass spectroscopy (SIMS) data that demonstrates a greater retention of N by In. This should lead to a greater drop in activity for In+N combination versus B+N one, in agreement with spreading resistance profiling (SRP) experiments. Loss of activity in In+B+N combination might be due to long range interactions between dopants.
Laser Thermal Induced Crystallization for 20 nm Device Structures
Authors: Yang Shenzhi , Thompson Michael O. 
Published: April 2011

ABSTRACTThe melt kinetics of shallow junction formation by laser thermal processes has been studied using transient conductance measurements. The melt and solidification dynamics of 20 nm amorphous layers were measured and shown to follow behaviors predicated by deeper melts, including explosive crystallization and interface bounce back. The effects of surface barrier oxides and metal absorber layers, required for CMOS process integration, were examined and shown to be nearly negligible. Quantitative evaluation of a device process window by these measurements was in good agreement with sheet resistance results. Finally, the effect of the buried oxide in SOI structures was investigated. Solidification velocities in such structures were reduced by a factor of three as compared with bulk silicon.
Why abrasive free Cu slurry is promising?
Authors: Kamigata Yasuo , Kurata Yasushi , Masuda Katsuyuki , Amanokura Jin , Yoshida Masato , Hanazono Masanobu 
Published: April 2011

ABSTRACTTo develop high signal speed semiconductor LSIs, Cu interconnection is one of the most important requirements. In the fabrication of Cu interconnections using CMP method, minimized dishing, erosion and reduction in micro-scratches are large issues to be realized. We performed a research for superior properties of Cu CMP. Finally, we succeeded in developing Abrasive Free (AF) Cu slurry suitable for these requirements.We also developed slurry for barrier (TaN) with a high selectivity between TaN and SiO2 of 50 to reduce oxide (SiO2) loss. This reduced oxide loss is directly related to obtaining a controlled circuit resistivity.By applying these two kinds of slurries, ULSIs with multilevel Cu interconnects and excellent reliabilities were obtained.
Polyurethane Pad Degradation and Wear Due to Tungsten and Oxide CMP
Authors: Moy Amy L. , Cecchi Joseph L. , Hetherington Dale L. , Stein David J. 
Published: April 2011

ABSTRACTPolyurethane polishing pads are commonly used for chemical-mechanical polishing (CMP) of semiconductor wafers. Structural, chemical, and mechanical property changes of the polishing pads due to CMP are examined. Tungsten and oxide film layers are polished from the wafer surface using the polishing pad and abrasive slurry system. The polishing pad surface is flattened with polishing, and hence, reducing the effective area for slurry transport. The abrasive is used for abrading off the film from the surface. W, Al, I, and K accumulate in the polishing pad after tungsten CMP and Si accumulates after oxide CMP. Material accumulates in the pad pores and grooves. Electron Microprobe X-ray Analysis and Wavelength Dispersive Spectrometry (WDS) were used to examine the changes across the thickness of the pad. Fourier Transform Infrared Spectroscopy (FTIR) was used to determine the changes to the polyurethane isocyanate group. The reduction in the isocyanate group and increase in the hydroxyl group after tungsten CMP indicates that a hydrolysis reaction of the isocyanate to form carboxylic acid occurs.
High-performance CMP Slurry with Inorganic/Resin Abrasive for Al/Low k Damascene
Authors: Yano Hiroyuki , Matsui Yukiteru , Minamihaba Gaku , Kawahashi Nobuo , Hattori Masayuki 
Published: April 2011

ABSTRACTCMP slurry with inorganic/resin abrasive was investigated for the Al/low k damascene wiring. [1] The slurry showed less scratching, higher polishing rate and better planarity. These advantages are attributable to the elasticity of the resin. The soft resin particle behaves as a cushion and prevents the scratching caused by agglomerated inorganic particles and foreign material. The springy feature of the resin particle increases the selectivity of removal rate at convex portions and concave portions. Furthermore, the pressure is loaded to the Al film surface effectively through the resin particle and higher CMP rate can be achieved even without chemicals such as oxidizers and acids. [2] This chemical free polishing would be the advantageous for preventing the corrosion of Al.
Modeling of Feature-Scale Planarization in STI CMP Using MESATM
Authors: Laursen Thomas , Kim Inki , Schlueter James 
Published: April 2011

ABSTRACTMESA is a feature-scale planarization model that predicts the changing topography of the wafer surface during the chemical mechanical polishing (CMP) process used in IC manufacturing. This model has previously been applied to the polish of inter-level dielectrics and copper. The present study is part of a model validation procedure for shallow trench isolation (STI) using experimental feature-scale data. It was carried out using the SpeedFam-IPEC Auriga polisher with SKW Associates 200-mm wafers (SKW3 MIT-STI-mask), Rodel IC 1000/1400 pads and Cabot SS-12 slurry. MESA accounts for observed differences in planarization using Rodel IC1000 with and without foam backing as well as the pattern-density dependence within each die. The data were obtained and plotted in such a way that the active-area and trench-oxide levels are displayed throughout the whole polish, including the points where active area clears to nitride and silicon as well as where trench oxide dishes below the silicon level. The pattern density effect is evident in both cases, but a comparison between the two pads shows less pattern density effect and improved planarization with the single IC 1000 pad.MESA is shown to predict the details of the topographical evolution for STI CMP on the feature scale. When validated by fitting the pad constants k1 and k2 to describe the planarization, MESA provides reasonably accurate predictions for the polish of any oxide pattern structure as long as the same CMP process is used.
Direct Visualization of Particle Dynamics in Model CMP Geometries
Authors: Zettner Claudia M. , Yoda Minami 
Published: April 2011

ABSTRACTChemical-mechanical polishing (CMP) involves complex mechanical and chemical interactions between a rough elastomeric pad, the wafer being polished and an abrasive slurry containing sub-micron diameter silica particles. The interaction between these abrasive particles and the wafer surface and their impact upon material removal rates is still unclear. Particle dynamics in a model CMP geometry are studied experimentally in this work. Only the particles that actually interact with, and presumably polish, the model wafer surface are visualized using total internal reflection fluorescence (TIRF). The effect of process properties such as particle diameter, particle material, pad-wafer separation and shear rate upon the particle concentration immediately adjacent to the wafer surface is investigated.
Multiprobe End-Point Detection for Precision Control of the Copper CMP Process
Authors: Laursen Thomas , Grief Malcolm 
Published: April 2011

ABSTRACTSentinelä is an optical multiprobe endpoint detection (EPD) system that has been developed by SpeedFam-IPEC (SFI) for the 200-mm and 300-mm Momentum orbital polishers. Sentinel EPD for copper CMP is based on monitoring the visible spectrum of light from a Xenon (Xe) flash lamp, which has been reflected by the wafer surface during polish. Large representative areas of the wafer are monitored from multiple locations in the pad continuously throughout the polish process. Spectra of reflected light from cleared and uncleared copper on a pattern wafer demonstrate a clear transition from copper to the underlying dielectric layer.With the Sentinel EPD system, the wafer is probed at optimized multiple locations constantly throughout the polish process by small-diameter light spots. The coverage of the monitoring is extensive and the radial coverage is substantial on a real-time basis. The EPD call is made based on an EPD signal, which displays the fractional copper coverage as a function of polish time. The detection of copper clearing on the SFI Momentum tools is very reliable and predictable, and not sensitive to process changes.
Comparison Study for TiN Films Deposited from Different Method: Chemical Vapor Deposition and Atomic Layer Deposition
Authors: Kim Byoung-Youp , Lee Seung-Hyun , Park Sang-Gee , Oh Ki-Young , Song Juho , Kim Do-Heyoung 
Published: April 2011

ABSTRACTThis paper compared two different film deposition processes for formation of TiN barrier layers, conventional TiCl4-based chemical vapor deposition and atomic layer deposition (ALD). The 30nm thick TiN film deposited by conventional TiCl4-based CVD at the process temperature of 600°C followed by NH3 post-deposition anneal showed about 180 μΩcm of resistivity, over 95 % of step coverage for the pattern aspect ratio of 6 on 0.35 μm contact diameters, and below 2 at.% of chlorine contents in the film. Meanwhile, the films deposited by ALD at 100°C lower process temperature than CVD showed much better film properties even without post-deposition anneal. It showed lower resistivity values and lower chlorine incorporation along with better step coverage characteristics. More detailed material analysis was done by AFM, SEM, and AES.
Electrochemical Properties of SnO2 Thin Films Doped with Bi and Si for Negative Electrode of Microbattery
Authors: Kim Young-Il , Moon Hee-Soo , Ji Kwang-Sun , Lee You-Kee , Park Jong-Wan 
Published: April 2011

ABSTRACTTin oxide has been proposed as a promising alternative anode material for microbatteries. It has been reported that its theoretical volumetric capacity is four times larger than that of carbon-based materials, while its gravimetric capacity is twice as large. In this experiment, optimal Si and Bi doped SnO2 films were prepared with e-beam evaporation to improve both the cycle performance and the reversible capacity. The films with addition of Si only exhibited reductions in aggregation of tin particles and formation of micro-cracks. However, there still remained cracks, which induce capacity loss during cycling. To improve capacity retention, Bi was added with Si to SnO2 films, which exhibited the highest reversible capacity of 200µAh/cm2-µm at 200th cycle. The films doped with Bi and Si were found to be ill-defined and featureless without noticeable particle aggregation and cracks. However, the films that underwent cycling tests showed again aggregated tin particles and formation of cracks, which would induce cell failure during cycling. We believe that some types of Li-Bi phases as mixed-conductor matrices have improved the cycle life.
Processing of yttria stabilized zirconia thin films by liquid fuel combustion chemical vapor deposition
Authors: Xu Zhigang , Wei Q. , Sankar Jag 
Published: April 2011

ABSTRACTYttria fully stabilized zirconia (YSZ) thin films have been successfully synthesized with atmospheric combustion chemical vapor deposition (ACCVD) technique with liquid fuel. Key processing parameters, such as the ratio of oxygen to liquid fuel in the flame, the concentration of metal reagents in the solution, the temperature of the substrate and substrate material, have been investigated. The as-grown films are characterized with X-ray diffraction and scanning electron microscopy. Within the range of experimental parameters, the phase of the film is predominantly of cubic structure. The phase and crystallinity of the films are strongly dependent upon the experimental variables.
Material and Electrical Characterization of Carbon-Doped Ta2O5 Films for Embedded DRAM Applications
Authors: Chu Karen , Cho Byeong-Ok , Chang Jane P. , Steigerwald Mike L. , Fleming Robert M. , Opila Robert L. , Lang Dave V. , Dover R. Bruce Van , Jones Chris D.W. 
Published: April 2011

ABSTRACTWe studied the effect of carbon incorporation on the material and electrical properties of Ta2O5 thin film. We doped the Ta2O5 films with carbon using pulsed-dc reactive and rfmagnetron sputtering of Ta2O5 performed in an Ar/O2/CO2 plasma. In thick (70 nm) films, an optimal amount (0.8 - 1.4 at.%) of carbon doping reduced the leakage current to 10−8 A/cm2 at +3 MV/cm, a four orders of magnitude reduction compared to that in a pure Ta2O5 film grown in similar conditions without CO2 in the plasma. This finding suggests that carbon doping can significantly improve the dielectric leakage property at an optimal concentration. X-ray Photoemission Spectroscopy (XPS) analysis showed the presence of carbonate in these electrically improved carbon-doped films. Analysis by high-resolution transmission electron microscopy (HRTEM) exhibited no morphological or structural changes in these carbon doped films. Carbon doping showed no improvement in the leakage current in thin (10 nm) Ta2O5 films. This phenomenon is explained by a defect compensation mechanism, in which the carbon-related defects remove carriers at low concentrations but form a hopping conduction path at high concentrations.
Role of Si(100) Surface Patterns in the Phase Separation of Cu/Sn Thin Films
Authors: Hu Qin , Zinke–Allmang Martin , Mitchell Ian V. 
Published: April 2011

ABSTRACTWe report on the competitive phase separation of copper and tin thin film deposits on a pre–patterned Si(100) surface. The initial pattern on Si(100) was achieved through a thermal decomposition process of an ex–situ grown oxide film. Copper and tin phase separation on silicon is a competitive process with Cu forming preferrably silicide. Sn is observed to cover the silicide clusters when present in a sufficient amount. The pre–patterning of the surface introduces a new length scale in the problem. Our data suggest that this length scale plays a role while the clustering (ripening) length scale is of the same order, i.e., during nucleation and the early phase separation, but that both length scales become independent once the length scale of ripening significantly exceeds the length scale of the surface pattern.
The Influence of Plasma Composition on the Properties of Plasma Treated Biomaterials
Authors: Cruz Nilson C. , Rangel Elidiane C. , Gadioli Giovana Z. , Mota Rogério P. , Honda Roberto Y. , Algatti Mauricio A. , Schreiner Wido H. 
Published: April 2011

ABSTRACTThe response of a biological environment when in contact with an artificial material is primarily determined by the material surface properties such as composition, contact angle and free surface energy [1,2]. Owing to that, different treatments have been employed to improve the performance of biocompatible materials. In this sense, plasma-based techniques are very attractive because they enable the surface processing of materials with virtually any geometry preserving bulk properties. Furthermore, other characteristics make plasma treatment of particular interest in biomaterial processing. Those characteristics include, for instance, a) the possibility of using a large number of different chemicals to introduce any desired functional group on the surface, b) the treatment is performed in an intrinsically sterile environment and, c) different kind of materials (such as ceramics, metals and polymers) including those chemically inert can be treated.
Synthesis and Properties of Al-Based Amorphous and Microcrystalline Thin Films
Authors: Ettl Christoph , Berger Lothar , Mrosk Joachim W. , Fecht Hans-Jörg 
Published: April 2011

ABSTRACTAmorphous metal alloys are ideally suited for interconnects in micro-electromechanical sys- tems (MEMS) because of their resistance against stress- and electromigration, and their stability in chemically aggressive environments, which should both lead to a substantial improvement of lifetime and reliability of robust sensors. While amorphous refractory metal alloys and amor- phous silicides are excellent interconnect materials for devices operating at elevated tempera- tures, these systems lack the cost-effective and easy interconnect processing of the prevalent polycrystalline aluminum alloy metallizations. Amorphous aluminum alloys are applicable to devices operating at up to 200°C, and their stressmigration resistance and chemical stability is far superior to conventional polycrystalline aluminum alloys. These new metallizations are very promising for processing interconnects, in particular because of their high strength and ductility, though having low density, and their relatively low electrical resistivity compared to other amor- phous metal alloys. Therefore these metallizations are especially suited for surface acoustic wave (SAW) sensors, where the interconnects are exposed to considerable mechanical strains. In this work amorphous Aluminum Yttrium alloy thin film metallizations deposited on appropriate sub- strates at room temperature (R.T.) by ultra-high vacuum (UHV) electron beam evaporation will be presented, and their mechanical and electronic properties together with their temperature sta- bility will be investigated.
Zinc Oxide/Copper Oxide Mixed Films Deposited by CVD
Authors: Chang Yuneng , Yeh Chihhsiang 
Published: April 2011

ABSTRACTMetal organic chemical vapor deposition (MOCVD) was used to prepare ZnO/Cu2O mixed films. The process condition studied were: deposition temperature from 360oC to 440oC, partial pressures of oxygen, 190-380 torr, precursor copper acetylacetonate (Cu(acac)2), 0.21 torr, and zinc acetylacetonate(Zn(acac)2), 0.45 torr. AES and XPS analysis showed average elemental content being Cu, 52-66%, Zn, 11-20%, O, 30-40%. Copper presented primarily as Cu(I) ions, and Zn as Zn(II) ions. SEM, SAM and XRD indicated that deposited films were polycrystalline with composite structure. Some films had a continuous ZnO thin layer with flat surface, equiax fine grained. On the top of ZnO layer were covered by discrete, irregular shape, coarse Cu2O grains. Primary Cu2O phases were (110), (111), and (200) orientation. ZnO phases were (002), and (103). SEM showed the impact of deposition temperature on Cu2O grain size. Such data were used to estimate the activation energy for grain growth. In fact, to our experiences from these studies, binary metal oxide CVD showed a wide spectrum of film microstructure and morphology. These phenomena reflect the result caused by both thermodynamics as film composition, and kinetics as mass transfer/ surface reaction rate.