bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non-Destructive Method for Simultaneous Mapping of Diffusion Length and Surface Recombination Velocity
Authors: Ostendorf Hans-Christoph , Endrös Arthur L. 
Published: April 2011

AbstractBulk and surface recombination are the main material parameters that determine the performance of crystalline silicon solar cells. We present a new method for the nondestructive, simultaneous mapping of the diffusion length and the surface recombination velocity of a silicon wafer. The method uses the hardware of the electrolytical metal tracer (ELYMAT). The separation between bulk and surface recombination is achieved by illuminating the sample with laser beams of two different colors. By solving the diffusion equation for both laser penetration depths the diffusion length and the surface recombination velocity can be calculated from the measured diffusion currents. First experiments are presented which show the basic feasibility of the method.
Application of Elastic Mid-IR-Laser-Light Scattering for Non-Destructive Inspection in Microelectronics
Authors: Kalinushkin Victor P. , Yuryev Vladimir A. , Astafiev Oleg V. , Buzynin Alexander N. , Bletskan Nikolay I. 
Published: April 2011

AbstractSome possible applications of the low-angle mid-IR-light scattering technique and some recently developed on its basis methods for non-destructive inspection and investigation of semiconductor materials and structures are discussed in the paper. The conclusion is made that the techniques in question might be very useful for solving a large number of problems regarding defect investigations and quality monitoring both in research laboratories and the industry of microelectronics.
Characterization of MOS Devices Fabricated on Carbon Implanted Silicon Substrates
Authors: Ban Ibrahim , Öztürk Mehmet C. , Christensen Kim , Maher Dennis M. 
Published: April 2011

AbstractIn this study, we present characterization of Metal-Oxide-Semiconductor (MOS) capacitors fabricated on carbon (C14) implanted silicon substrates. Carbon was implanted at an energy of 50 keV with doses ranging from 1 × 1012 cm−2 to 4.1×1015 cm−2. Metal-Oxide-Silicon (MOS) capacitors were fabricated and used to determine the MOS capacitance-voltage (C-V) and capacitance-time (C-t) behavior. These measurements revealed a strong correlation between carrier lifetime and the carbon dose. Degradation in lifetime was observed for carbon dose levels as low as 4 × l012 cm−2. At carbon doses equal to and above 6.4 × l013 cm−2, extremely low generation lifetimes were obtained (∼ 10−7 sec). On the other hand, degradation in C-V characteristics was observed only for carbon doses above 2.7 × l014 cm−2. Below this dose, both flatband voltage and interface trap density of the carbon implanted samples were comparable to those of the monitors. Analysis of the samples by cross sectional transmission electron microscopy revealed the absence of extended defects even in samples with high carbon dose levels.
Comparative Study of Experimental Techniques for Boron Profiling at Poly-Si/SiO2 Interface
Authors: Furtsch M. , Bevk J. , Bude J. , Downey S. W. , Krisch K. S. , Moriya N. , Silverman P. J. , Luftman H. S. 
Published: April 2011

AbstractElectrical characterization of MOS structures and device modeling require accurate information about dopant concentration, particularly at the poly-Si/SiO2 interface. We compare four experimental techniques (secondary ion mass spectrometry SIMS, resonant ion mass spectrometry RIMS, differential Hall effect profiling, and spreading resistance analysis) to measure boron and free carrier concentrations in poly-Si, SiO2 and crystalline Si. We find that no single technique completely characterizes the entire MOS structure, and that spreading resistance analysis in particular substantially underestimates the free carrier concentration at the poly-Si/SiO2 interface. We conclude that in most cases of technological interest the magnitude of the poly depletion effect scales with the average carrier concentration at some distance away from the interface and that the interfacial effects, such as dopant segregation, are of only secondary importance. These findings are supported by theoretical modeling of capacitance-voltage behavior of boron-doped MOS capacitors.
Magnetic Exchange Coupling in Asymmetric Trilayers of Co/Cr/Fe
Authors: Theis-BrÖhl K. , Scheidt R. , Zeidler TH. , Schreiber F. , Zabel H. , Mathieu TH. , Mathieu CH. , Hillebrands B. 
Published: April 2011

ABSTRACTWe present first results of anisotropy and exchange coupling studies of a system with two different magnetic layers (Fe and Co) separated by a nonmagnetic Cr spacer. For the magnetic measurements we used the longitudinal magneto-optical Kerr effect and ferromagnetic resonance. The hysteresis data obtained from the trilayer were fit to a theoretical model which contains both bilinear and biquadratic coupling. The in-plane anisotropy was found to be four-fold with the same easy-axis orientation for both the Fe and the Co layers. An analysis of the easy-axishysteresis loops indicates long period oscillatory coupling and also suggests a short period coupling.
Magnetism of Bct Iron Grown In (001) FeIr Superlattices
Authors: Andrieu Stéphane , Bauer Philippe , Lahatra-Razafindramisa Fils , Hennet Louis , Snoeck Etienne , Brunel Michel , Piecuch Michel 
Published: April 2011

ABSTRACTIn this paper, we show that iron can be grown by MBE in a body centered tetragonal structure in (001) FeIr superlattices. The growth, structure and morphology of these superlattices are briefly resumed. A variation of the BCT Fe magnetic moment depending on the Jr thickness is observed. This variation is demonstrated to come from a variation of the BCT Fe atomic volume, due to the competition of the Fe and Ir stresses. A magnetic transition from a non-magnetic to a low spin ferromagnetic state depending on the atomic volume is thus observed.
Structural Studies and Magnetotransport Properties of Sputtered Ni/Co Multilayers
Authors: Freitag J.M. , Bian X. , Altounian Z. , Ström-Olsen J.O. , Cochrane R.W. 
Published: April 2011

ABSTRACTFerromagnetic/ferromagnetic Ni/Co multilayers were prepared by DC-magnetron sputtering with component layer thicknesses ranging from 40 Å down to 5 Å. Structural characterizations by x-ray diffractometry show a well-defined compositional modulation along the film growth direction and a preferred (111) crystalline orientation. A longitudinal magnetoresistance ΔR/R over 2.7% with a sensitivity of ~0.11%/Oe was measured at room temperature in small fields less than 20 Oe. The highest room temperature sensitivity obtained in this system was 0.16%/Oe. Magnetoresistive sensitivity was found to vary inversely with the number of bilayers in the multilayers. The magnetic anisotropy of the films as determined by MOKE magnetometry is correlated to the magnetoresistance and indicative of an AMR effect.
(100) Epitaxial and (111) Polycrystalline Spin Valve Heterostructures on si (100): Magnetotransport and the Importance of Interface Mixing in Ion Beam Sputtering
Authors: Joo Hyun S. , Hashim Imran , Atwater Harry A. , Watson Thomas J. 
Published: April 2011

ABSTRACTWe have investigated magnetoresistance properties of (100) epitaxial, (11) textured and polycrystalline spin valve heterostructures of the form Ni80Fe20/Cu/NiNi80Fe20/Fe50Mn50 on (100) Si substrates by ultra high vacuum (UHV) ion beam sputtering at room temperature. Magnetoresistance was measured as a function of Cu interlayer thickness (ti) with 10 Å ≤ti ≤ 100 Å and the maximum was found at 20 Å in the case of (100) epitaxial spin valves. Highly (11) textured spin valves with heterostructure configurations similar to the (100) spin valves were found to have a slightly lower magnetoresistance than the (100) heterostructures, but the functional dependence of the magnetoresistance on ti was very similar.Interface mixing during the sputtering process by energetic neutral bombardment was found to significantly affect the magnetoresistance. Samples were made under various sputtering conditions (gas pressure, ion beam energy, target and substrate configuration) that could enhance or suppress high energy neutral bombardment of the growing film surface. Samples made under the conditions that suppressed neutral bombardment showed higher magnetoresistance and more abrupt interfaces as confirmed by small angle X-ray diffraction analysis of interface mixing by energetic neutral bombardment during sputter deposition.
Microstructure and Magnetic Properties of Nanocrystalline Fe93-x-yZr7B,xCuy Alloys
Authors: Kopcewicz M. , Grabias A. , Nowicki P. 
Published: April 2011

ABSTRACTAn unconventional technique combining Mossbauer spectroscopy with the effects induced by magnetic radio-frequency fields (if collapse and if sidebands) is employed to study the microstructure and magnetic properties of nanocrystalline clusters of bcc Fe formed by annealing amorphous Fe93-x-yZr7B,xCuy (x=6, 8, 12, y=0, 2) alloys at 500-600°C. The rf-Mössbauer experiments allow us to distinguish magnetically soft nanoclusters from magnetically harder microcrystalline phases. The dependence of the bcc Fe phase formation on the alloy composition is discussed. The Mössbauer results are supplemented by DSC measurements.
Bonding and Penetration at Metal/Self-Assembled Organic Monolayer Interfaces
Authors: Jung D. R. , Czanderna A. W. , Herdt G. C. 
Published: April 2011

ABSTRACTThe purpose of research on metals (M) deposited onto self-assembled monolayers (SAMs) is to understand the interactions between the metal and eventually metal oxide overlayers on well-ordered organic substrates. Applications of M/SAM and inorganic/SAM research results to the understanding of real inorganic/organic interfaces in vacuum and under environmental conditions can potentially play a key role in the development of advanced devices with stable interfacial properties. The results of selected M/SAM studies to date are reviewed, and MISAM combinations ranked according to reactivity and penetration. Specific examples of reactive interfaces (Cu/COOH, Cr/several groups) and nonreactive interfaces with penetration (Ag/CH3, Ag/COOH) are used to illustrate the extremes.
Adhesive Systems Based on Functionalized Block Copolymers
Authors: Saunders Randall S. , Kent Michael S. 
Published: April 2011

ABSTRACTFunctionalized block copolymers were synthesized as adhesion promoters using Ring-Opening Metathesis Polymerization (ROMP). They were designed for glass/epoxy and copper/epoxy interfaces. The former contained triethoxysilane groups in the first block and secondary amine groups in the second. The latter contained imidazole groups in the first and amine groups in the second block. These block copolymers were shown to form ordered monolayers on the respective glass and copper surfaces using neutron reflectivity. Adhesion measurements showed an enhancement of adhesion after application of these block copolymers.
Cleaning of SiO2: Differences Between Thermal and Deposited Oxides
Authors: Ravkin M. , Farber J. J. , Malik I. J. , Zhang J. , Jensen A. J. , de Larios J. M. , Krusell W. C. 
Published: April 2011

ABSTRACTThe effects described in this paper are specific to cleaning with mechanical brush scrubbing. Oxides, both thermally grown and deposited are common cleaning applications for mechanical brush scrubbing. Thermally grown oxides present higher final defect counts after scrubbing with deionized water compared to deposited oxides. In this paper we present our results on the cleaning of unpolished and polished oxide surfaces and show differences in these results to be dependent on the chemistry used for cleaning and the degree of hydrophilicity of the wafer surface.
Studies of the Relationship between Megasonics, Surface Etching, and Particle Removal in SC-1 Solutions
Authors: Cohen S. L. , Rath D. , Lee G. , Furman B. , Pope K. R. , Tsai R. , Syverson W. , Gow C. , Liehr M. 
Published: April 2011

ABSTRACTWafer cleaning studies have been performed so as to understand the influence of acoustic (megasonic) energy on particle removal in dilute SC-1 solutions. Surface etching alone (up to 60Å) has been found to be insufficient to completely remove silicon nitride surface particles from native oxide surfaces in the absence of megasonics. For megasonic cleaning processes the minimum surface etching required for complete nitride particle removal is significantly lower (between 3–12Å) than for a non-megasonic process. The exact 'threshold' for surface etching will depend on the chemical nature of the particle/surface and the megasonics power. Megasonics energy does not appear to enhance chemical etching of the substrate, at least for silicon oxide substrates, however, it significantly improves particle removal. This data suggests that the particle removal process can benefit from both a thermally activated component (etching) as well as an acoustic component (cavitation/ acoustic streaming).
Measuring Diffusion Lengths in Epitaxial Silicon by Surface Photovoltage
Authors: Lowell John , Wenner Valerie , Debusk Damon 
Published: April 2011

ABSTRACTIn CMOS, the use of epitaxial layers for prevention of latch-up in logic technologies is well-known and pervasive. One of the crucial parameters is the amount of metallic contamination due to transition metals such as Fe in the epi since this phenomena effects both device performance and quality. However, the ability to measure this parameter on product material is not generally available due to inherent problems with most known methods. The limitation of traditional surface photovoltage is that the deep optical penetration of over a hundred microns is well-beyond the depth of most epitaxial layers and does not accurately profile the epitaxial region [1]. In this paper we report on the application of optical surface photovoltage (SPV) using a set of ultra-shallow optical filters to both quantify and qualify as-grown epitaxial layers on CZ P-type silicon. We believe that a non-contact, SPV measurement of Fe concentration and diffusion lengths within an epitaxial region has not been previously reported.
Analyzing Atomic Force Micrographs Using Spectral Methods
Authors: Halepete Sameer D. , Lin H. C. , Fang Simon J. , Helms C. R. 
Published: April 2011

ABSTRACTMicroroughness is a critical parameter in ULSI device interface reliability and has been shown to effect several critical MOS electrical properties. The atomic force microscope (AFM) has become the instrument of choice for silicon surface microroughness analysis. The parameters usually specified to characterize roughness are average and root mean square roughness. However, these parameters are spatial averages and can have the same value for two significantly different surfaces. Spectral analysis using the Fast Fourier Transform (FFT) has been applied as a powerful tool to analyze AFM data by looking at roughness as a function of spatial wavelength. The Fast Hartley Transform, being a real transform, is faster than the FFT and is better suited for this analysis. It has been used here to derive spectral information from the AFM height data. Before evaluating the transform, cancellation of any tilt or warp in the AFM data is done to remove frequency components which interfere with other spectral information. A PC-based computer program to determine the transform and its magnitude will be described. The application of this method to analyze data from Si and SiO2 surfaces as a function of pre-oxidation cleaning chemistry will be presented. Significantly better insight into the spatial distribution of roughness is obtained, when compared to previous implementations.
Removal of Metallic Contaminants and Native Oxide from Silicon Wafer Surface by Pure Water Containing a Little Dissolved Oxygen
Authors: Hayami Yuka , Suzuki Miki T. , Okui Yoshiko , Ogawa Hiroki , Fujimura Shuzo 
Published: April 2011

ABSTRACTCleaning effects of pure water containing dissolved oxygen of very low concentration (LDO water) to metallic contaminants on silicon wafer surface were confirmed. To maintain the concentration of the dissolved oxygen in water, experiments were performed in a glove box in which ambience was controlled so as to satisfy Henry's law between the water and the ambient gas. In the experiment using intensionally contaminated wafers, residual metal contaminants except copper on Si-surface decreased from 1014atoms/cm2to 1011atoms/cm2after the 1ppb hot LDO treatment at boiling point. This effect depended on the concentration of dissolve oxygen, treatment temperature, and rinsing time. Contact angle of the wafer surface increased gradually from about 10 [deg] with decrease in the residual metals and jumped up to about 90 [deg]. when the amount of residual metals reached to minimum. Then absorption peak of Si-O bonds in FT-IR-RAS spectra also disappeared. These results therefore show that hot LDO water removed metal contaminants from the wafer surface with etching of the native oxide.
Pulsed-Laser Deposition of Titanium Nitride
Authors: Jiang Wenbiao , Grant Norton M. , Thomas Dickinson J. , EVANS N.D. 
Published: April 2011

AbstractThe pulsed-laser deposition technique has been used to form thin films of TiN on (100)-oriented single crystal substrates of silicon and rocksalt. Using atomic force microscopy, it was revealed that TiN films grown on silicon at substrate temperatures ranging from 50°C to 500°C were extremely smooth—the mean roughness being ~ 0.2 nm. Thin TiN films deposited on freshly cleaved NaCl were found to be epitaxial at substrate temperatures as low as 50°C. Epitaxy in this latter system is believed to be due to the structural similarity between film and substrate and the almost exact 4:3 coincident site lattice.
On- and Off-AXIS Large-Area Pulsed Laser Deposition
Authors: Greer James A. , Tabat M. D. 
Published: April 2011

AbstractOver the past few years Pulsed Laser Deposition (PLD) has become a popular technique for the deposition of a wide variety of thin films, and PLD systems are currently found in numerous industrial, government, university, and military laboratories. At present, it is estimated that well over 200 different materials have been deposited by PLD and the list keeps growing. However, even with all the interest in laser deposition the technique has not yet emerged as an industrial process. At the moment, industry still prefers standard thin film growth techniques such as magnetron and ion beam sputtering, chemical vapor deposition, and electron beam evaporation for production applications. These processes have been in use for decades and have demonstrated the ability to deposit films of most materials over large areas with excellent uniformity at reasonable cost and deposition rates. Furthermore, an entire infrastructure has been built up to support these processes including standardization of deposition rate monitors, power sources, target and crucible sizes, etc. On the other hand, laser-deposition is still an emerging technology, and relatively little infrastructure exists to adequately support either research or industrial applications. Since there are several materials which are difficult if not impossible to grow in thin-film form by more conventional techniques, it is expected that as pulsed laser-deposition matures this unique process will take its rightful place on the manufacturing line.
Growth and Properties of Carbon Nitride Thin Films
Authors: John Zhang Z. , Yang Peidong , Lieber Charles M. 
Published: April 2011

AbstractRecent research on carbon nitride thin films grown using pulsed laser deposition combined with atomic beam techniques is reviewed. the composition, growth mechanism and phases of these films have been systematically investigated. the nitrogen composition was found to increase to a limiting value of 50% as the fluence was decreased for laser ablation at both 532 nm and 248 nm wavelengths. Time of flight mass spectroscopy investigations of the ablation products have shown that the fluence variations affect primarily the yield of the carbon reactant. these experiments demonstrate that the overall film growth rate determines the average nitrogen composition, and furthermore, suggest that a key step in the growth mechanism involves a surface reaction between carbon and nitrogen. INfrared spectroscopy has been used to assess the phases present in the carbon nitride thin films as a function of the overall nitrogen content. these measurements have shown that a cyanogen-like impurity occurs in films with nitrogen compositions greater than 30%. Studies of thermal annealing have shown, however, that this impurity phase can be eliminated to yield a single phase C2N material. IN addition, systematic studies of the electrical resistivity and thermal conductivity of the carbon nitride films are discussed.
Fabrication of a Free-Standing, Synthetic, Single Crystal Diamond Plate Using Ion Implantation and Plasma-Enhanced Chemical Vapor Deposition
Authors: Posthill J.B. , Malta D.P. , Humphreys T.P. , Hudson G.C. , Thomas R.E. , Rudder R.A. , Markunas R.J. 
Published: April 2011

AbstractUsing a specific combination of energetic and chemical processes we have grown homoepitaxial diamond on and lifted it off of a type Ia natural C(100) crystal. Before growth, the C(100) crystal is exposed to a self implant of 190keV energy and dose of 1E16 cm-2. Low temperature (~600°C) homoepitaxial diamond growth conditions were used that are based on water-alcohol source chemistries. To achieve layer separation (lift-off), samples were annealed to a temperature sufficient to graphitize the buried implant-damaged region. Contactless electrochemical etching was found to remove the graphite, and a transparent synthetic (100) single crystal diamond plate of 17.5μm thickness was lifted off. This free-standing diamond single crystal plate was characterized and found to be comparable to homoepitaxial films grown on unimplanted single crystal diamond.
Competitive Oxidation During Buried Oxide Formation Using Separation by Plasma Implantation of Oxygen (Spimox)
Authors: Liu Jingbao , Sundar Kumar Iyer S. , Min Jing , Chu Paul , Gronsky Ron , Hu Chenming , Cheung Nathan W. 
Published: April 2011

AbstractWe have recently demonstrated a new implantation technique called SPIMOX (separation by plasma implantation of oxygen) to synthesize silicon-on-insulator structures using plasma immersion ion implantation (PIII) process. the implantation is performed by applying a large negative bias to a Si wafer immersed in an oxygen plasma created by an ECR source. Since the technique has no mass analysis, coexistence of O+ and O2+ ions in oxygen plasma can cause a non-Gaussian profile of the as-implanted oxygen distribution. We observed that during post-implantation annealing, the ripening process of the oxide precipitates depends on depth and concentration of the oxygen peaks. IN addition, implanted oxygen can migrate towards the Si surface during annealing, preventing a continuous buried oxide layer formation. IN this paper, we report our observation on the effect of the implantation profile on the competitions between internal oxidation at different depths and between internal and surface oxidation processes. With an additional He implantation, we demonstrate that the nucleation of oxide precipitation can be enhanced.