bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of an organic dye solution for laser cooling by anti-Stokes fluorescence
Authors: Bartholomew Jarett L. , DeBarber Peter A. , Heeg Bauke , Rumbles Garry 
Published: April 2011

ABSTRACTSeveral independent groups have observed optical cooling by means of anti-Stokes luminescence in condensed media. The most promising materials are grouped into two categories: ion-doped glasses and organic dye solutions. It is this latter group that we focus our efforts on. Recent studies by our group show that irradiating a solution of rhodamine 101 in the long wavelength wing of the absorption spectrum results in the observation of optical cooling. To improve upon the initial observation of a few degree drop in temperature requires a better understanding of the conditions and phenomena leading to anti-Stokes luminescence in dye solutions. We develop a thermal lensing experiment to obtain fluorescence quantum yields of various dye solutions. The importance of concentration, choice of solvent, deuteration, and acidification are discussed.
Electrical and Optical Studies of the Organic Thin Film Devices Produced by Cluster Beam Deposition Methods
Authors: Kim J.Y. , Kim E.S. , Choi J.-H. 
Published: April 2011

ABSTRACTThe neutral and ionized cluster beam deposition (NCBD and ICBD) methods have been applied to fabricate the new double-layer organic light emitting devices (OLEDs) with the structure of indium-tin-oxide (ITO)-coated glass/spin-coated poly[2-(N-carbazolyl)-5-(2-ethyl-hexyloxy)-1,4-phenylenevinylene] (CzEH-PPV)/8-hydroxyquinoline aluminum (Alq3)/Li:Al. The surface morphology profiles measured by atomic force microscopy (AFM) showed that the cluster beam deposition methods are efficient in producing uniform and smooth film surfaces. Photo- and electro-luminescence (PL, EL) spectroscopies demonstrated that while the new hole transporting medium CzEH-PPV is susceptible to the bombardment of energetic ionized beam, the introduction of the neutral buffer layer significantly improves the device characteristics, i.e., lower threshold and turn-on voltages and higher external quantum efficiency (EQE). In addition, the effect of doping of highly fluorescent dye (DCM) into Alq3 layer showed a complete energy transfer, color-tuning capability and higher EQE compared to the undoped devices.
Polygermyne: Germanium sheet polymers with efficient near-infrared luminescence
Authors: Vogg Günther , Brandt Martin S. , Meyer Lex J.-P. , Stutzmann Martin , Hajnal Zoltán , Szücs Bernadett , Rauenheim Thomas 
Published: April 2011

ABSTRACTThe structural, optical and electronic properties of the Ge sheet polymer poylgermyne are summarized. Prepared via topotactic transformation of Zintl-phase CaGe2, (GeH)n forms a layered crystal in a tr6 stacking sequence with a distance of 5.65 Å between adjacent layers. The photoluminescence at 1.3 eV is excited nearly resonantly with a Stokes shift of 0.2 eV. Together with band structure calculations this shows that polygermyne has a direct band gap.
Photoluminescence and Raman Spectroscopy Studies of H+ Ion Implanted SOI Structures Formed by Hydrogen Ion Slicing
Authors: Popov Vladimir P. , Tyschenko Ida E. , Zhuravlev Konstantin S. , Morosov Ivan I. 
Published: April 2011

ABSTRACTH+ ion implanted SOI structures formed by hydrogen ion slicing have been investigated by Raman spectroscopy and photoluminescence (PL). After implantation the wafers have been heat-treated by either furnace annealing (FA) or rapid thermal annealing (RTA). It has been found that implantation of 3 × 1017 H+/cm2 results in the formation of the amorphous Si layer (a-Si) inside silicon film on insulator. Structural transformations in a-Si depended on the annealing conditions. FA led to crystallization of a-Si and to the formation of monocrystalline silicon films. RTA results in the formation of the layers containing a high density of Si nanocrystals. A comparison of the Raman measurements with the PL data allows to conclude that PL bands obtained near 420 and 500 nm are not associated with the radiative recombination in Si nanocrystals.
Luminescence of Lu2O3:Tm3+ nanoparticles
Authors: Donegá Celso de Mello , Zych Eugeniusz , Meijerink Andries 
Published: April 2011

ABSTRACTThis paper presents for the first time a comparison between the luminescence properties (viz. emission and excitation spectra, lifetimes, and concentration quenching) of nanocrystalline and microcrystalline Lu2O3:xTm3+ (x= 0.1– 5 mol%). The results show that the most important difference between the two size regimes is the higher defect concentration in the nanoparticles. These defects give rise to a broadband emission (λmax = 430 nm), and to partial quenching of the Tm3+ emission, in addition to the expected concentration quenching by cross-relaxation between Tm3+ ions. The defect concentration seems to be similar in all nanocrystalline samples, so that those with the lowest Tm3+ concentrations experience the most pronounced quenching. The nature of these defects is as yet unknown. The local structure around the Tm3+ ions is not noticeably different in the two size regimes. No evidence of phonon confinement or quantum size effects was observed in the Tm3+luminescence.
Red Emitting Electroluminescent Devices Using Ga2O3 Phosphor Thin Films Prepared by Sol-Gel Process
Authors: Minami Tadatsugu , Shirai Tetsuya , Miyata Toshihiro 
Published: April 2011

ABSTRACTHigh-luminance red-emitting thin-film electroluminescent (TFEL) devices have been developed using Ga2O3 phosphor thin films prepared by a sol-gel deposition method. Single-insulating-layer-type TFEL devices were fabricated by depositing a Cr- or a Eu-activated Ga2O3 phosphor thin film onto a thick BaTiO3 ceramic sheet insulator. The Ga2O3:Cr or Ga2O3:Eu thin-film emitting layer was prepared by a sol-gel process using gallium acethylacetonate (Ga(C5H7O2)3) as the Ga source with Cr(C5H7O2)3 or EuC13 as the dopant source, respectively. A high red luminance of 622 cd/m2 was obtained for a Ga2O3:Cr TFEL device driven by a sinusoidal wave voltage at 1 kHz.
Novel Fluorescent Labels Prepared by Layer-by-Layer Assembly on Colloids for Biodetection Systems
Authors: Yang Wenjun , Trau Dieter , Renneberg Reinhard , Yu Nai-Teng , Caruso Frank 
Published: April 2011

ABSTRACTFluorescent polystyrene microparticles with different sizes were produced by the consecutive assembly of fluorescently labeled polyelectrolytes using the layer-by-layer self-assembly method. Film growth was characterized by microelectrophoresis and fluorescence microscopic image (FMI) analysis. Alternating negative and positive ζ-potentials with deposition of each successive polyelectrolyte layer demonstrated that the alternate adsorption of polyelectrolytes was achieved. FMI analysis provided direct measurement of the fluorescence intensity of single microparticles. The subsequent deposition of a protein (immunoglobulin G, IgG) layer onto the fluorescent microparticles was confirmed by a sandwich immunoassay.
Color Centers in Magnesium Doped Polycrystalline Alumina
Authors: Brock L. R. , Mishra K. C. , Raukas Madis , Lapatovich Walter P. , Wei George C. 
Published: April 2011

ABSTRACTWe have investigated color centers in MgO-doped polycrystalline alumina (PCA) using absorption, excitation, and emission spectroscopy. Most of the color centers that were reported in earlier studies of the crystalline material have been observed to be present in the polycrystalline material. The absorption spectral features observed in the PCA are attributed to various color centers; however, they are not sufficiently resolved to make unique assignments. Suitable combinations of excitation and emission spectroscopy and also measurements at low temperature were therefore used to identify most of the color centers in this material.Among the numerous color centers that we have identified in PCA are variations of electron centers including F, F+, F2+, F22+ and F+-Mg ((Vo•-MgAl')x). The most prominent oxygen vacancy related defect observed at room temperature was the F+-Mg center, with absorption bands located at 217 and 249 nm, and an emission band at 303 nm. This center can be thought of as being formed by association of an F+ center with a Mg defect. The single crystal sapphire samples containing no Mg show only F+ (Vo•) centers with 230 and 257 nm absorption bands, and a 328 nm emission band.Low temperature (22 K) fluorescence excitation measurements of PCA led to emission from F22+center at 467 nm. Additionally, there is evidence that the observed 368 nm emission band could be attributed to the zero-phonon line associated with the F2+center.
Advanced Ion Implantation Technology for High Performance Transistors
Authors: Suguro Kyoichi , Murakoshi Atsushi , Iinuma Toshihiko , Akutsu Haruko , Shibata Takeshi , Sugihara Yoshikazu , Okumura Katsuya 
Published: April 2011

ABSTRACTCryo-implantation technology is proposed for reducing crystal defects in Si substrates. The substrate temperature was controlled to be below at -160°C during ion implantation. No dislocation was observed in the implanted layer after rapid thermal annealing. Pn junction leakage was successfully reduced by one order of magnitude as compared with room temperature implantation. Precise dose control is indispensable in channel region of high performance MOSFETs. In order to improve the precision of implanted dose, chip size implantation technology without photoresist mask was developed. In this technology, chip-by-chip implantation can be carried out by step-and-repeat wafer stage, and different implantation conditions are available in the same wafer independent of wafer size.
Computer Simulation of Decaborane Implantation into Silicon, Annealing and Re-crystallization of Silicon
Authors: Insepov Zinetulla , Yamada Isao 
Published: April 2011

ABSTRACTMolecular Dynamics (MD) and Activation-Relaxation Technique (ART) models of decaborane ion implantation into Si and following rapid thermal annealing (RTA) processes have been developed. The B and Si atomic positions for implantation of accelerated decaborane ions, with total energy 3.5- 15 KeV, into Si substrate were obtained by MD simulation. The main difference between monomer and decaborane ion implantation with the same doses is the formation of a large amorphized area in a subsurface region for the decaborane case. The number of displaced Si atoms shows non-linear energy dependence at low impact energies. At higher energies ofthe investigated range of the decaborane energy range, however, a linear dependence is observed in accordancewith the prediction of the Kinchin-Pease formula. A new method that incorporates Activation-Relaxation Technique (ART) with MD has been developed and used to study re-crystallization of Si amorphized in the implantation process.
Effect of Arsenic on Extended Defect Evolution in Silicon
Authors: Brindos R. , Jones K. S. , Law M. E. 
Published: April 2011

ABSTRACTThe effect of arsenic on {311} defect formation was determined for temperatures ranging from 700°C to 800°C. Arsenic well structures were formed at arsenic concentrations of 3×1017, 3×1018, and 3×1019 cm−3. A 40 keV 1×1014 cm−2 silicon implant, that is known to form {311} defects, was then incorporated into the structures. Extended defect evolution and dissolution was then studied after furnace annealing at 700°C, 750°C and 800°C for various times. It was determined that arsenic has a strong affect on the nucleation of extended defects. However, once the defects were formed, the dissolution time constant was the same for all concentrations considered. The activation energy for defect dissolution was found to be 3.4eV and was also independent of arsenic concentration. Using a newly developed {311} model in the FLOOPS process simulation software, the effect of the arsenic on {311} formation and dissolution was simulated. It was found that by using a pair model with an arsenic-interstitial binding energy of 0.95eV, the experimental results were able to be simulated.
Influence of Arsenic Clustering and Precipitation on the Interstitial and Vacancy Concentration in Silicon
Authors: Brindos R. , Clark M. H. , Jones K. S. , Griglione M. , Gossmann Hans-J. , Agarwal A. , Murto B. , Andideh E. 
Published: April 2011

ABSTRACTThe point defect injection from arsenic precipitation was studied using boron marker layers and antimony doped superlattices. Comparisons of arsenic and germanium amorphizing implants showed similar boron marker layer diffusion enhancements after spike annealing. The results indicate that the end of range damage caused by the implants was the source of the diffusion enhancement. Additional annealing cycles showed that there was retardation in the diffusion enhancement of the boron marker layers for precipitation range arsenic implants. Antimony marker layers showed no diffusion enhancement due to vacancy injection. The results of the experiments indicate that arsenic-interstitial complexes are the cause of the decrease flux of interstitials to the bulk.
A Study of the Deactivation of High Concentration, Laser Annealed Dopant Profiles in Silicon
Authors: Takamura Yayoi , Jain Sameer , Griffin Peter B. , Plummer James D. 
Published: April 2011

ABSTRACTAs semiconductor device dimensions continue to decrease, the main challenge in the area of junction formation involves decreasing the junction depth while simultaneously increasing the active dopant concentration. Laser annealing is being investigated as an alternative to rapid thermal annealing (RTA) to repair the damage from ion implantation and to activate the dopants. With this technique, uniform, box-shaped profiles are obtained, with dopant concentrations that can exceed equilibrium solubility limits. Unfortunately, these super-saturated dopant concentrations exist in a metastable state and deactivate upon further thermal processing. In this work, a comprehensive study of the deactivation kinetics of common dopants (P, B, and Sb) was performed across a range of annealing conditions. For comparison, As deactivation data from the work of Rousseau et al.1 is also presented. Each dopant exhibits different deactivation behavior, however, As and P can be classified as unstable species while B and Sb are stable against deactivation until higher temperatures of 700-800°C. In addition, a means of maintaining these metastably doped layers is being investigated with the goal of meeting the International Technology Roadmap for Semiconductors (ITRS) requirements for ultrashallow junctions.
Antimony and Boron Diffusion in Silicon and Silicon Germanium under the Influence of Point Defects Injection by Rapid Thermal Anneal
Authors: Dan Aihua , Willoughby Arthur F. W. , Bonar Janet M. , McGregor Barry M. , Dowsett Mark G. , Ormsby Terry J. 
Published: April 2011

ABSTRACTThe effect of point defect injection on the diffusion of antimony and boron in silicon and silicon-germanium alloys has been studied by comparison of inert with injection diffusions. In this work, Sb and B in Si were used as control wafers to investigate Sb and B diffusion behavior in Si0.9Ge0.1. The point defect injection technique was carried out by rapid thermal annealing (RTA) Sb and B in Si and Si0.9Ge0.1 samples with the various surface coatings in either oxygen or ammonia atmospheres to inject either interstitial or vacancy defects. The diffusion profiles for as-grown and RTA annealed samples were measured by Secondary Ion Mass Spectrometry (SIMS). Diffusivities for B in Si and Si0.9Ge0.1 were obtained using computer simulations of the measured boron profiles for their annealed samples. Sb diffusion in Si and Si0.9Ge0.1 was found enhanced by vacancy injection and retarded by interstitial injection. The enhanced B diffusion in Si and Si0.9Ge0.1 was found by interstitial injection. These results confirm that Sb diffusion in Si0.9Ge0.1 is primarily dominated by vacancy-mediated mechanism, while B diffuses in Si0.9Ge0.1 by an interstitially mediated mechanism. The effect of the RTA diffusion time on the B diffusion in Si and Si0.9Ge0.1 has also been investigated. The diffusivity versus diffusion time of B in Si and Si0.9Ge0.1 for inert and injection samples is presented. It was found that the shorter annealing time had the faster diffusion. This suggested that it caused by transient diffusion effect arising from point defects.
Atomistic Modeling of Amorphization in Silicon
Authors: Pelaz Lourdes , Marqués Luis A. , Gilmer George H. , Barbolla Juan 
Published: April 2011

ABSTRACTWe discuss atomistic simulations of ion implantation and annealing of Si over a wide range of ion dose and substrate temperatures. The DADOS Monte Carlo model has been extended to include the formation of amorphous regions, and this allows simulations of dopant diffusion at high doses. As the dose of ions increases, a continuous amorphous layer may be formed. In that case, most of the excess interstitials generated by the implantation may be swept to the surface as the amorphous layer regrows, instead of diffusing through the crystalline region. This process reduces the amount of transient enhanced diffusion during annealing. This model also reproduces the dynamic annealing during high temperature implants.
Evaluation of Mechanical and Tribological Behavior, and Surface Characteristics of CMP Pads
Authors: Sikder A. K. , Irfan I. M. , Kumar Ashok , Belyaev A. , Ostapenko S. , Calves M. , Harmon J. P. , Anthony J. M. 
Published: April 2011

ABSTRACTChemical Mechanical Planarization (CMP) occurs at an atomic level at the slurry/wafer interface and hence slurries and polishing pads play a critical role in the successful implementation of this process. Surface roughness, visco-elastic properties, thickness and pore size also play an important role in this process. Unfortunately the mechanical properties of polyurethane polishing pads used in CMP are poorly understood. Here we have studied the mechanical and visco-elastic properties and surface morphology of CMP pads using nano-indentation and dynamic mechanical analysis along with high resolution scanning electron microscopy. A state-of-the-art Universal Micro-Tribometer was used to measure the pad deformation behavior under load. A novel non-destructive scanning ultrasonic transmission technique was also used to characterize inhomogeneity of the visco-elastic properties of full-size CMP pads. Results obtained by different techniques were analyzed to demonstrate methods for quick and reliable evaluation of pad quality for current CMP technology.
Analysis of Copper to Tantalum Transition in Copper Cmp
Authors: Kang J.M. , Wu S. , Selvaraj T. , Foo P.D. 
Published: April 2011

ABSTRACTThe evolution from Cu to Ta surface during Cu CMP has been investigated. As a first step of Cu CMP, removing excess Cu on field area to Ta often gives rise to topography issues such as dishing or erosion. The exposure of Ta is detected by in-situ reflectance measurement, where the downward slope-start signifies the beginning of Ta exposure. For blanket wafers, the maximum remaining Cu thickness at slope-start increases with initial Cu thickness. Applying lower polishing pressure and table speed, so-called soft landing, near the Cu-Ta transition stage results in thicker remaining Cu. In patterned wafers, Ta exposure starts near high pattern density areas such as wide lines, and contrary to blanket wafers, remaining Cu thickness at slope-start cannot be correlated simply with initial Cu thickness. In this experiment, with increasing initial Cu thickness, remaining Cu thickness at slope-start decreased. The amount of dishing is largely proportional to the initial Cu thickness.
Direct Measurement of Planarization Length for Copper Chemical Mechanical Planarization Polishing (CMP) Processes Using a Large Pattern Test Mask
Authors: Lefevre Paul , Gonzales Albert , Brown Tom , Martin Gerald , Tugbawa Tamba , Park Tae , Boning Duane , Gostein Michael , Nguyen John 
Published: April 2011

ABSTRACTWehaveusedalargepatterntestmaskandaspecificarrangementofstructuresonawaferfor direct measurement of an average planarization length for copper chemical mechanical polishing (CMP)processes.Weproposenewminimum,maximum,andaverageplanarizationlengthdefini-tions, based on up and down area measurements as a function of trench width. The average pla-narizationlengthisusefulforqualitativelycomparingtheplanarizationcapabilityofcopperCMP processes. We have also performed several experiments that show how the average planarization length depends on polish process settings such as down force and relative speed, as well as on consumables such as pad and slurry.
Wafer Nanotopography Effects on CMP: Experimental Validation of Modeling Methods
Authors: Lee Brian , Boning Duane S. , Baylies Winthrop , Poduje Noel , Hester Pat , Xia Yong , Valley John , Koliopoulus Chris , Hetherington Dale , Sun HongJiang , Lacy Michael 
Published: April 2011

ABSTRACTNanotopography refers to 10-100 nm surface height variations that exist on a lateral millimeter length scale on unpatterned silicon wafers. Chemical mechanical polishing (CMP) of deposited or grown films (e.g., oxide or nitride) on such wafers can generate undesirable film thinning which can be of substantial concern in shallow trench isolation (STI) manufacturability. Proper simulation of the effect of nanotopography on post-CMP film thickness is needed to help in the measurement, analysis, diagnosis, and correction of potential problems.Our previous work has focused on modeling approaches that seek to capture the thinning and post-CMP film thickness variation that results from nanotopography, using different modeling approaches. The importance of relative length scale of the CMP process used (planarization length) to the length scale of the nanotopography on the wafer (nanotopography length) has been suggested.In this work, we report on extensive experiments using sets of 200 mm epi wafers with a variety of nanotopography signatures (i.e., different nanotopography lengths), and CMP processes of various planarization lengths. Experimental results indicate a clear relationship between the relative scales of planarization length and nanotopography length: when the planarization length is less than the nanotopography length, little thinning occurs; when the CMP process has a larger planarization length, surface height variations are transferred into thin film thickness variations. In addition to presenting these experimental results, modeling of the nanotopography effect on dielectric CMP processes is reviewed, and measurement data from the experiments are compared to model predictions. Results show a good correlation between the model prediction and the experimental data.
A Planarization Model in Chemical Mechanical Polishing of Silicon Oxide using High Selective CeO2 Slurry
Authors: Lee Jong Won , Yoon Bo Un , Hah Sangrok , Moon Joo Tae 
Published: April 2011

ABSTRACTThis paper attempts to establish planarization model in chemical mechanical polishing of silicon oxide using high selective ceria slurry. Though removal rate of the high area is increased due to a high pressure focused on the area with abrasive and pad, the removal rate of the same area is not increased but decreased even in the very beginning of polishing with ceria slurry. It also observed that only the elevated area is polished and dishing is not occurred during the polishing in high selective ceria CMP. In this work, it is proposed that ceria abrasives are filled in the low trench area and then support the pad as well as high area during the CMP, which results in planarization without dishing.