bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preliminary Results on Large Area X-ray a-SiC:H Multilayer Detectors with Optically Addressed Readout
Authors: Vieira Manuela , Vygranenko Yuri , Fernandes Miguel , Louro Paula , Sanguino Pedro , Fantoni Alessandro , Schwarz Reinhard 
Published: April 2011

AbstractThis paper investigates a feasibility of using a large area image sensor with an optically addressed readout for medical X-ray diagnostic imaging. A device prototype comprises a multilayer glass/ZnO:Al/p (a-SiC:H)/i (a-Si:H)/ n (a-SiC:H)/ i(a-Si:H)/p (a-SiC:H)/ a SiNx/ITO structure coupled to a scintillator layer. Here, the p-i-n-i-p structure works in both sensing and switching modes depending on the biasing conditions. A numerical simulation is used to optimize the semiconductor layer thicknesses in order to achieve a photocurrent matching between back-to-back diodes in switching mode. The charge carrier transport within the p-i-n-i-p structure is also analyzed under different electric and optical biasing conditions. A physical model supports the results.
Hot-Wire Deposited Nanocrystalline Silicon TFTs on Plastic Substrates
Authors: Taghibakhsh Farhad , Adachi Michael M. , Karim Karim S. 
Published: April 2011

AbstractHot-wire chemical vapor deposition (HWCVD) technique was used to deposit nanocrystalline silicon (nc-Si) thin film transistors (TFT) on thin polyimide sheets. Two straight tantalum filaments at 1850°C with a substrate to filament distance of 4 cm was used to deposit HWCVD nc-Si with no thermal damage to plastic sheet. Top-gate staggered TFTs were fabricated at 150°C and 250°C using a HWCVD nc-Si channel, PECVD silicon nitride gate dielectric, and microcrystalline n+ drain/source contacts. Leakage current of 3.3×10-12 A, switching current ratio of 3×106, and sub threshold swing of 0.51 V/decade were obtained for TFTs with aspect ratio of 1400 µm / 100 µm fabricated at 150°C. The highest electron field effect mobility was found to be 0.3 cm2/V.s observed for TFTs deposited at lower substrate temperature. Measurements showed superior threshold voltage stability of HW nc-Si TFTs over their amorphous silicon (a-Si) counterparts.
Tailored Deposition by LPCVD of Non-stoichiometric Si Oxides and their Application in the Formation of Si Nanocrystals Embedded in SiO2 by Thermal Annealing
Authors: Morana Bruno , de Sande Juan Carlos G. , Rodríguez Andrés , Sangrador Jesús , Rodríguez Tomás , Avella Manuel , Prieto Ángel Carmelo , Jiménez Juan 
Published: April 2011

AbstractSilicon oxide films with excess of Si were deposited by Low Pressure Chemical Vapor Deposition. The growth rate of the films and the excess of silicon in them have been modeled using a Face-centered Central Composite Design experiment. Samples annealed at 1100°C show luminescence (665 nm) at 80K and at room temperature associated to Si nanocrystals.
Interdigitated Back Contact Silicon Heterojunction (IBC-SHJ) Solar Cell
Authors: Lu Meijun , Bowden Stuart , Das Ujjwal , Burrows Michael , Birkmire Robert 
Published: April 2011

AbstractInterdigitated back contact silicon heterojunction (IBC-SHJ) solar cells have been developed. This structure has interdigitated p/n amorphous silicon (a-Si:H) films deposited by plasma enhanced chemical vapor deposition (PECVD) on the backside of crystalline silicon (c-Si) wafers, with light irradiating the front surface. IBC-SHJ cells possess advantages over front junction a-Si:H/c-Si heterojunction cells due to minimized current losses in the illuminating side, and over traditional diffused back-junction cells due to low temperature processing combined with the potential of high voltages for the heterojunction. Current-voltage curves, spectral response and laser beam induced current maps have been used to characterize the IBC-SHJ cells. It was found that the IBC-SHJ cell has non-linear illumination level dependence that correlates with effective minority-carrier lifetime. As the performance of these cells is very sensitive to the quality of passivation on front surface, they are ideally suited as a diagnostic tool for detail characterization of surface passivation. Initial cell structures have achieved independently confirmed cell efficiencies of 11.8% under AM1.5 illumination. Device simulation shows an efficiency of higher than 20% can be expected after optimizing the IBC-SHJ cells.
Investigation of Diamond Grit Size and Conditioning Force Effect on CMP Pads Topography
Authors: Sun Ting , Borucki Leonard , Zhuang Yun , Philipossian Ara 
Published: April 2011

ABSTRACTIn this study, incremental loading and interferometry analysis were performed on Rohm and Haas IC1000 plain pad surfaces to investigate the effects of diamond size and conditioning force on pad topography. The Rohm and Haas IC1000 plain pad was conditioned by Mitsubishi Materials Corporation 100-grit and 325-grit diamond discs under 3.6 and 8.0 lb. Two pad samples were taken for each disc and each conditioning force test. For each pad sample, a custom-made incremental loading device (ILD) was used to measure pad surface mechanical response under different loads. When loads were applied to the pad sample surface, the pad surface displacement was measured. A decay length was extracted from the log plot of the pressure ratio vs. the change in pad surface displacement. The decay length generally increased with the diamond size and conditioning force. Both dry and wet pad samples were analyzed by the incremental loading device. Results showed that wet pad samples had higher decay lengths than dry pad samples. Separately, optical interferometry was used to probe dry pad sample surfaces without contact and produce surface height probability density functions (PDFs). For all pad samples, the pad surface height PDFs exhibited an exponential tail and a decay length was extracted, which represented the distance over which the pad surface height probability dropped by a factor of 1/e. The decay lengths extracted from the optical interferometry analysis were consistent with those extracted from the incremental loading experiments, indicating that the optically measurable pad surface characteristic had a practical interpretation in terms of the pad surface mechanical response.
Low Defect Ceria for ILD CMP
Authors: Kasthurirangan Jai , Parker John , Bettis Tiffany , Dowell Charles 
Published: April 2011

ABSTRACTThe reduction of wafer scratching is a key goal driving the commercial development of CMP slurries. To better understand the underlying abrasive particle properties critical to the scratch performance of ILD CMP slurries, the scratching behavior of ceria slurries prepared with a range of particle size characteristics are characterized. Scratch results are presented and two effects are proposed to account for the findings. The Removal Rate Effect relies solely on the observed inverse proportionality between scratching and removal rate. This interpretation is consistent with a simple surface balance of scratches but suggests that removal rate differences dominate scratch performance. The Managed Tail Effect considers the effect of particle characteristics on both the creation and the removal of scratches. For a given particle population, the larger particles are assumed to dominate scratch creation. However, larger particles are also seen to drive removal rate which affects the removal of scratches during polishing. This interpretation implies that optimal scratch performance for a ceria ILD CMP slurry will be obtained when the width of the ceria particle's size distribution is optimized relative to its mean.
Micromachined Shear Stress Sensors for Characterization of Surface Forces During Chemical Mechanical Polishing
Authors: Mueller Andrew , White Robert , Manno Vincent , Rogers Chris , Anjur Sriram , Moinpour Mansour 
Published: April 2011

ABSTRACTThis paper describes the fabrication and calibration of micromachined shear stress sensors intended for characterization of the local pad-wafer contact forces present during chemical-mechanical polishing. Sensors consist of arrays of microfabricated poly-dimethyl-siloxane (PDMS) posts and are able to measure forces ranging from 2 to 200 μN. The posts are 100 μm high and have diameters of 40-100 μm. Calibrated post deflection sensitivities are linear and lie between 0.2 μm/μN and 1.3μm/μN. Sensor design, fabrication, and calibration are detailed. Feasibility is established for sensor integration into a CMP scale model test setup, including an optical viewing method for observing post deflection during polishing. Initial micrographs of post deflection during polishing do not yet have sufficient resolution to determine the microscale forces during polishing.
Composite polymer core – ceria shell abrasive particles during silicon oxide CMP
Authors: Armini Silvia , De Messemaeker Joke , Burtovyy Ruslan , Luzinov Igor , Whelan Caroline M. , Moinpour Mansour , Maex Karen 
Published: April 2011

ABSTRACTAlthough dielectric polishing is primarily mechanical in nature, surface chemical effects can be tailored to enhance material removal, selectivity and planarity. The use of ceria abrasives in oxide polishing is particularly attractive because of favorable polishing characteristics that are generally not obtainable using conventional fumed or colloidal silica abrasives. Unfortunately, a characteristic of ceria abrasive is an enhanced tendency toward defectivity in comparison with conventional silica. Entirely novel composite structures comprising 300 nm polymer particles coated by ceria (specific surface area of the powder 61 m2/g), are achieved by either adding silane coupling agents (Composite A) or tuning the pH in order to form electrostatic attractive interactions between the core and the shell (Composite B). The polymer core shows mechanical properties that are highly tunable by variation of its synthesis parameters, while the major advantage of the ceria coating is an enhanced chemical action of the abrasive particles, commonly referred to as the chemical tooth model. In this study we report the evolution of RR, haze, and defects such as particles and scratches in CMP experiments on high-density plasma (HDP) silicon oxide using four abrasive types (14 nm primary size ceria particles, 300 nm polymer particles, composites A and B) at pH 3 and 10. Interestingly, the two types of composite exhibit different RR. This is attributed to differences in morphology and surface composition. Composite B presents more similarities with the ceria, as confirmed by particle / silica surface adhesion forces in different pH solutions, measured by a colloidal AFM technique.
Development and Optimization of Slurry for Ru CMP
Authors: Kim In-Kwon , Kwon Tae-Young , Park Jin-Goo , Park Hyung-Soon 
Published: April 2011

ABSTRACTIn this study, Ruthenium (Ru) chemical mechanical planarization (CMP) slurry was studied and developed to apply it for the formation of Ru bottom electrode in DRAM capacitor. An acidic chemical was chosen as both oxidant and etchant. The effects of the chemical on polishing and etching behavior were investigated as functions of chemical concentration and pHs. The static etch rate of Ru increased with increase of chosen chemical concentration. Also, thin Ru oxide was generated in chemical solution. The highest etching and removal rate were obtained in slurry of pH 6. Ru over etching was generated due to the high etch rate of Ru, and then good planarity was not obtained. However, because Ru over etching was prevented due to low etch rate of Ru, the plarnarity and isolation of each capacitor in slurry of pH 9 was acquired successfully.
Are the Materials Properties of Indiumnitride Dominated by Defects?
Authors: Specht Petra , Hong William , Weber Eicke R. 
Published: April 2011

AbstractIndium nitride (InN) is a promising yet technologically challenging material with a high defect density and unusual material properties. Its high electron mobility may be utilized in high power electronic devices, and its high absorbance and low energy optical response make it a promising candidate for multi-junction, high-efficient solar cell technology. Studies of absorption and photoluminescence optical response of epitaxial InN resulted in a large correction of the fundamental bandgap from the originally proposed 1.9 eV to now below 0.7 eV. Yet, it is still debated if the commonly measured optical transitions below the original high bandgap values are actually caused by a large concentration of defects, on the order of 1020/cm3, rather than reflecting a low fundamental bandgap. Many applications of this material, e.g. in high-efficient solar cell technology, are primarily dependent on the successful production of a contacted p-n junction, which has not yet been achieved. This contribution addresses the controversy in the bandgap discussion of InN. Valence electron energy loss spectroscopy (VEELS) of InN allows spatially resolved analysis of the density of states in the transmission electron microscope (TEM). Standard optical characterization is compared with results from TEM characterization.
Defect Contribution to the Photoluminescence from Embedded Germanium Nanocrystals Prepared by Ion Implantation and Sputter Deposition Methods
Authors: Giri Pravat Kr , Das Kaustuv , Roy Samit K 
Published: April 2011

AbstractIn this work, we present a comparative study of vibrational and luminescent properties of Ge nanocrystals (NCs) prepared by ion implantation (Process I) and radio frequency (RF) sputter deposition techniques (Process II). Optical Raman studies reveal presence of strain in the Ge NCs embedded in SiO2 in both cases. Polarization dependent Raman scattering studies show that process I yields NCs with surface symmetrical Raman modes only, whereas process II yields additional surface quadrupolar Raman modes. Photoluminescence studies using 488 nm excitation show broad PL emissions peaked at ∼2.3 in all the samples with varying intensities. PL studies on Ar implanted and similarly annealed SiO2 layers confirm that 2.3 eV emission is originated from oxygen deficient defects in the SiO2 matrix. PL studies with 325 nm excitation show additional strong peaks at higher energies, which are believed to be due to Ge/O interface defects. It is concluded that room temperature visible light emission from embedded Ge NCs is primarily dominated by the oxygen deficient defects in SiOx matrix and non-bridging oxygen surrounding the Ge NCs, while light emission due to quantum confined carriers in the NCs are quenched perhaps due to inherent strain in the embedded NCs.
Thermally Induced Relaxation in GaInNAsSb Quantum Well Structures
Authors: Pickett Evan , Bank Seth , Yuen Homan , Bae Hopil , Sarmiento Tomás , Marshall Ann , Harris James 
Published: April 2011

AbstractGaInNAsSb quantum wells with GaNAs barriers, grown via molecular beam epitaxy (MBE) on 100–oriented GaAs substrates at varying temperatures, were analyzed using photoluminescence (PL), high-resolution x-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive spectrometry (EDS). Samples grown at 420 °C, 440 °C, and 470 °C were analyzed, as were two pieces of the 440 °C growth temperature sample that had been annealed at 740 °C and 820 °C. These measurements showed that the decrease in PL with higher growth temperatures was due to the onset of 3D growth and the nucleation of dislocations. The degradation associated with overannealing was likely due to dislocation nucleation. The poor PL associated with low growth temperatures was due to another mechanism, most likely arsenic anti-site defects. EDS measurements showed greater composition uniformity with lower growth temperatures, as expected, and also showed that there was no ordered indium-rich or indium-poor phase separation at any temperature. Phase separation upon annealing was not observed.
Anomalous Evolution of Bubbles in Krypton-Implanted SiO2
Authors: Assaf Hannan , Ntsoenzok Esidor , Barthe Marie-France , Leoni Elisa , Ruault Marie-Odile , Ashok S. 
Published: April 2011

AbstractThermally grown SiO2 was implanted at room temperature with 220 keV Kr in order to generate bubbles/cavities in the sample. The formation and thermal stability of these bubbles/cavities is studied in this work. Transmission Electron Microscopy (TEM), Rutherford Backscattering Spectrometry (RBS) and Positron Annihilation Spectroscopy (PAS) were used to provide a comprehensive characterisation of defects (bubbles, vacancy, Kr and other types of defects) created by Kr implantation in SiO2 layer. These measurements suggest that the bubbles observed with TEM were a consequence of the interaction between Kr and vacancies (V), with VnXem complexes created in the whole of implanted zone. After annealing, bubbles/cavities disappear from SiO2 due to the strongly desorption of Kr and the decrease in vacancy concentration.
Characteristics of Strained GaAsSb(N)/InP Quantum Wells Grown by Metalorganic Chemical Vapor Deposition on InP Substrates
Authors: Xu Dapeng , Huang Juno Yu-Ting , Park Joo Hyung , Mawst Luke J , Kuech Thomas F , SONG XUEYAN , Babcock Susan E 
Published: April 2011

AbstractGaAsSb (N) superattices (SLs) grown on InP substrates using metalorganic vapor phase epitaxy are investigated by high resolution X-ray diffraction (XRD), low temperature photoluminescence (PL), and high resolution transmission electron microscopy (TEM). XRD shows very sharp satellite peaks and pendellosung fringes, which indicates excellent crystalline quality and abrupt interfaces in the GaAsSb (N)/InP SL, with Sb varies with 0.2 to 0.7. Low temperature PL shows clearly different features between the 25% Sb and 44% Sb samples. A band alignment difference is proposed to explain these behaviors. Experimental data establishes that the transition from a type-I to a type-II heterostructure occurs for a Sb-content of approximately 40%, which agrees well with the prediction by Model Solid Theory. While N incorporation degrades the PL intensity, it also provides the greater electron confinement needed to achieve mid-IR emission from GaAsSbN/GaAsSb type-II QWs
Nanocavity Buffer Induced by Gas Ion Implantation in Silicon Substrate for Strain Relaxation of Heteroepitaxial Si1-xGex/Si Thin Layers
Authors: Raïssi Mahfoudh , Regula Gabrielle , Belgacem Chokri Hadj , Coudreau Cyril , Nitsche Serge , Lancin Maryse , Holländer Bernhard , Robert Florent , Fnaiech Mustapha , Ntsoenzok Esidor , Lazzari Jean-Louis 
Published: April 2011

AbstractTo weight the importance of a nanocavity buffer in a SiGe deposition substrate, some P type (001) FZ Si wafers are implanted (A samples) or not (B samples) at room temperature with 5×1016 He+ cm–2 at 10keV. They are annealed at 700°C for one hour to form a nanocavity layer close to the Si surface. Then, the wafers are carefully chemically cleaned in a clean room to remove both organic and metallic impurities from the surface. They are coated either by 210 nm (A) or 430 nm (B) Si1−xGex (x=0.20±0.02) alloy grown at 575°C for 0.42 hour by low pressure chemical vapor deposition (LP-CVD) with a growth rate of 8 to 17 nm.mn−1. Both kinds of samples are studied by cross section transmission electron microscopy, X-rays diffraction, Rutherford backscattering, atomic force microscopy and etch pit counts. The association of these techniques demonstrates that the thin SiGe layer which is deposited on sample A is fully relaxed and that the threading dislocation density (estimated to hardly reach 4×103cm−2) is at least one order of magnitude lower than what is obtained so far using ion implantation assistance in SiGe layer growth on Silicon. The roughness of the SiGe surface is low enough to stand a further Si epitaxy. Nevertheless, the mechanism involved responsible for the threading dislocation annihilation and/or confinement is still unclear.
An Evaluation of an Automated Detection Algorithm to Count Defects Present in X-Ray Topographical Images of SiC Wafers
Authors: Brazil Ian , McNally Patrick J. , O'Reilly Lisa , Danilewsky Andreas , Tuomi Turkka O. , Lankinen Aapo , Säynätjoki Antti , Simon Rolf , Soloviev Stanislav , Rowland Larry B. , Sandvik Peter M. 
Published: April 2011

AbstractAn evaluation of an algorithm used to extract Threading Screw Dislocation defect data from Synchrotron White Beam X-Ray Topographical images of SiC wafers is reported. This extraction involves a two-fold process; firstly the algorithm highlights the appropriate defect and secondly updates the counter to provide a final result of defect count. The result of the automated algorithm is compared to hand counts in all cases, this allowing a critical analysis of the technique. Improvements to this algorithm have been made since last reported by the same authors, which are discussed. The analysis herein was also performed on a much larger sample of SiC wafer images than previously used by the same authors [1] allowing a better judgment of performance and critical evaluation. The algorithm is also compared with a previous algorithm that was used. Advantages and deficiencies in the algorithm are outlined and other potential avenues for extraction of the data are also discussed.
Gate-All-Around (GAA) Fully Depleted (FD) Cantilever Channel MOSFET with High-k Dielectric and Metal Gate
Authors: Dey Sagnik , Lee Se-Hoon , Joshi Sachin V. , Majhi Prashant , Banerjee Sanjay K. 
Published: April 2011

AbstractA MOSFET formed by a Si cantilever channel suspended between source/drain “anchors” wrapped all-around by high-κ dielectric and metal gate is demonstrated. The device shows excellent subthreshold characteristics and low leakage currents due to the fully depleted body and the gate-all-around architecture implemented with a high-κ dielectric and metal gate. At the same time this also allows a high drive current due to mobility enhancements arising from volume inversion of the cantilever channel such that a large ION/IOFF is achieved.
Sub-30 nm FinFETs with Schottky-Barrier Source/Drain Featuring Complementary Metal Silicides and Fully-Silicided Gate for P-FinFETs
Authors: Lee Rinus Tek Po , Tan Kian-Ming , Liow Tsung-Yang , Lim Andy Eu-Jin , Lo Guo-Qiang , Samudra Ganesh S. , Chi Dong-Zhi , Yeo Yee-Chia 
Published: April 2011

AbstractWe investigated the material and electrical characteristics of platinum and ytterbium silicides for potential applications as metallic Schottky-barrier source/drain (S/D) and fully-silicided (FUSI) gate electrodes in fin field-effect transistors (FinFETs). Due to the low electro-negativity parameter of ytterbium, a low temperature silicidation process was developed to avoid the reaction of ytterbium with the isolation regions (i.e. SiO2 and SiN) to integrate ytterbium silicide successfully in mesa-isolated n-FinFETs. The integration of FUSI metal gate into p-FinFETs was also explored in this work and a novel two-step silicidation process that integrates simultaneously two different phases of platinum silicide with the appropriate work function values for gate electrode and source/drain application was demonstrated.