bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Mobility Nanocrystalline Silicon TFTs for Display Application
Authors: Han Min-Koo , Han Sang-Myeon 
Published: April 2011

AbstractNanocrystalline silicon (nc-Si) thin film transistors (TFTs) of which active layer thickness was 100nm were fabricated using inductively coupled plasma chemical vapor deposition (ICP-CVD) at 150°C. The fabricated nc-Si TFT exhibits rather high field effect mobility exceeding 22cm2/Vs and excellent sub-threshold slope of 0.45V/dec. The nc-Si film deposited 150°C as an active layer of the TFT shows high crystallinity more than 70% and very thin incubation layer less than 20nm. ICP-CVD provides high density plasma with reduced ion bombardment during the deposition on nc-Si and He dilution can enhance the decomposition of SiH4 into Si, SiHX radicals and atomic H, so that high quality nc-Si film can be fabricated. The gate insulator SiO2 film deposited by ICP-CVD at 150°C shows good electrical characteristics such as flat band voltage of -1.8V and breakdown voltage of 6.2MV/cm.
Pecvd Grown p-i-n Si and Si,Ge Thin Film Photodetectors For Integrated Oxygen Sensors
Authors: Ghosh Debju , Shinar Ruth , Dalal Vikram L. , Zhou Zhaoqun , Shinar Joseph 
Published: April 2011

AbstractRecent efforts to advance photoluminescence (PL)-based oxygen sensors have focused on developing compact, field-deployable devices. This has led to organic light emitting device (OLED)-based sensors with a structurally integrated [OLED excitation source]/[sensing film] module. To additionally integrate a photodetector (PD), PECVD for fabrication of thin-film p-i-n and n-i-p Si- and Si,Ge-based PDs was employed. O2 concentrations are advantageously determined by monitoring the effect of O2 on shortening the PL decay time &#61556; of an oxygen-sensitive dye, rather than on quenching its PL intensity. This approach, which employs pulsed OLEDs, eliminates the need for frequent sensor calibration, minimizes issues associated with background light, and eliminates the need for optical filters, which lead to bulkier sensors. However, it requires PDs with response times significantly shorter than &#61556;. Therefore, the development of thin-film PDs focused on decreasing their response time, and understanding the factors affecting it. In this paper we show that boron diffusion during growth from the p+ to the i layer increases the response time of PECVD grown p-i-n PDs. Incorporating a SiC buffer layer and fabricating superstrate structures, where the p+ layer is grown last, decrease it. Additionally, ECR fabricated PDs show a slower response in comparison to VHF PECVD-grown PDs.
Modeling and Characterization of the Hydrogenated Amorphous Silicon Metal Insulator Semiconductor Photosensors for Digital Radiography
Authors: Safavian Nader , Vygranenko Y. , Chang J. , Kim Kyung Ho , Lai J. , Striakhilev D. , Nathan A. , Heiler G. , Tredwell T. , Fernandes M. 
Published: April 2011

AbstractBecause of the inherent desired material and technological attributes such as low temperature deposition and high uniformity over large area, the amorphous silicon (a-Si:H) technology has been extended to digital X-ray diagnostic imaging applications. This paper reports on design, fabrication, and characterization of a MIS-type photosensor that is fully process-compatible with the active matrix a-Si:H TFT backplane. We discuss the device operating principles, along with measurement results of the transient dark current, linearity and spectral response.
Comparative Study of Solid-Phase Crystallization of Amorphous Silicon Deposited by Hot-wire CVD, Plasma-Enhanced CVD, and Electron-Beam Evaporation
Authors: Stradins Paul , Kunz Oliver , Young David L. , Yan Yanfa , Jones Kim M. , Xu Yueqin , Reedy Robert C. , Branz Howard M. , Aberle Armin G. , Wang Qi 
Published: April 2011

AbstractSolid-phase crystallization (SPC) rates are compared in amorphous silicon films prepared by three different methods: hot-wire chemical vapor deposition (HWCVD), plasma-enhanced chemical vapor deposition (PECVD), and electron-beam physical vapor deposition (e-beam). Random SPC proceeds approximately 5 and 13 times slower in PECVD and e-beam films, respectively, as compared to HWCVD films. Doping accelerates random SPC in e-beam films but has little effect on the SPC rate of HWCVD films. In contrast, the crystalline growth front in solid-phase epitaxy experiments propagates at similar speed in HWCVD, PECVD, and e-beam amorphous Si films. This strongly suggests that the observed large differences in random SPC rates originate from different nucleation rates in these materials while the grain growth rates are relatively similar. The larger grain sizes observed for films that exhibit slower random SPC support this suggestion.
Elastic Properties of Several Silicon Nitride Films
Authors: Liu Xiao , Metcalf Thomas H , Wang Qi , Photiadis Douglas M 
Published: April 2011

AbstractWe have measured the internal friction (Q-1) of amorphous silicon nitride (a-Si3Nx) films prepared by a variety of methods, including low-pressure chemical-vapor deposition (LPCVD), plasma-enhanced chemical-vapor deposition (PECVD), and hot-wire chemical-vapor deposition (HWCVD) from 0.5 K to room temperature. The measurements are made by depositing the films onto extremely high-Q silicon double paddle oscillator substrates with a resonant frequency of ~5500 Hz. We find the elastic properties of these a-Si3N4 films resemble those of amorphous silicon (a-Si), demonstrating considerable variation, depending on the film growth methods and post deposition annealing. The internal friction for most of the films shows a broad temperature-independent plateau below 30 K, characteristic of amorphous solids. The values of Q-1, however, vary from film to film in this plateau region by more than one order of magnitude. This is typical for tetrehedrally bonded amorphous thin films, like a-Si, a-Ge, and a-C. The PECVD films have the highest Q-1 just like an ordinary amorphous solid, while LPCVD films have an internal friction more than one order of magnitude lower. All the films show a reduction of Q-1 after annealing at 800°C, even for the LPCVD films which were prepared at 850°C. This can be viewed as a reduction of structural disorder.
Recent Progress in Up-Scaling of Amorphous and Micromorph Thin Film Silicon Solar Cells to 1.4 m2 Modules
Authors: Meier Johannes , Kroll Ulrich , Benagli Stefano , Roschek Tobias , Huegli Andreas , Spitznagel Joel , Kluth Oliver , Borello Daniel , Mohr Michael , Zimin Dmitri , Monteduro Giovanni , Springer Jiri , Ellert Christoph , Androutsopoulos Girogios , Buechel Gerold , Zindel Arno , Baumgartner Franz , Koch-Ospelt Detlev 
Published: April 2011

AbstractIn this paper an overview of our developments towards industrialization of thin film silicon PV modules is presented. Amorphous silicon p-i-n solar cells have been developed in medium size single-chamber R&D KAI-M PECVD reactors. High initial efficiencies of 10.6 % and stabilized of 8.6 % could be achieved for a 1 cm2 a-Si:H p-i-n solar cell of 0.20 m thick i-layer deposited on TCO from Asahi U type (SnO2). On our in-house developed LPCVD ZnO we could further improve the stabilized a-Si:H p-i-n efficiency to a similar level of 8.5 %. Incorporating such cells in commercial available front TCO of lower quality still leads to high initial mini-module aperture efficiencies (10 × 10 cm2) of 9.1% and stabilized ones of 7.46% (independently measured by ESTI JRC-Ispra).Transferring the processes from the KAI-M to the industrial size 1.1×1.25 m2 KAI-1200 R&D reactors resulted in a-Si:H modules of 110.6 W using commercial TCO, respectively 112.4 W when applying in-house developed LPCVD front ZnO. Both initial module performances have been independently measured by ESTI laboratories of JRC Ispra. A typical temperature coefficient for the module power of -0.22 %/°C (relative loss) has been deduced from temperature dependent I-V characteristics at ESTI laboratories of JRC Ispra. Finally, micromorph mini-modules of 10 % initial aperture efficiency have been fabricated.
Time-resolved Cavity Ringdown Spectroscopy as a Monitoring Technique of Nanoparticles in Pulsed VHF Plasmas
Authors: Nagai Takehiko , Smets Arno H. M. , Kondo Michio 
Published: April 2011

AbstractTime-resolved cavity ringdown (τ-CRD) spectroscopy has been applied to monitor the sylil (SiH3) radicals and nano-particles in pulsed very high frequency (VHF) silane (SiH4)/hydrogen (H2) plasmas under microcrystalline silicon (μc-Si:H) deposition conditions. After the plasma ignition, a small constant cavity loss (~100 ppm) on timescales smaller than ~1 s has been observed, whereas on time scales larger than ~1 s after plasma ignition, an additional cavity loss is observed. By variation of the wavelength of the CRD laser pulse, we demonstrate that the cavity loss on time scales smaller than ~1 s reflects the SiH3 absorption. On time scales larger than ~1 s, the additional cavity loss corresponds to the loss of light due to mainly scattering at the nano-particles. Under the conditions studied, the light scattering at nano-particles can be described by Rayleigh scattering during its initial growth. After ~ 2.5 s, the cavity loss reflects the transition of the scattering mechanism from dominant Rayleigh to dominant Mie-scattering. These results are discussed in terms of nano-particles growing in time and further confirmed by additional scanning electron microscopy analyses on the nano-particles created in the plasma pulse.
Advances in Understanding and Control of CMP Performance: Contact-Hydrodynamics at Wafer, Groove, and Asperity Scale
Authors: Muldowney Gregory P. 
Published: April 2011

ABSTRACTExamining CMP at any scale, one finds coupled contact mechanics and fluid mechanics. Increasingly sophisticated experimental and computational techniques have revealed aspects of solid-solid interaction and slurry flow at the wafer and groove scale and, more recently, at the texture scale. Successful prediction of CMP performance hinges on identifying universal physics that span these scales. In this paper we first review results of novel asperity-scale experiments that characterize the pad texture both as a solid topography subject to contact deformation and as an equivalent porous medium for slurry flow. These measures reveal that much of the texture volume is inactive as flow space, a feature confirmed quantitatively by computational modeling of flow across a conditioned CMP pad surface built from 3-D microscopy images. For hydrodynamics, the findings establish active fluid volume per unit area as the property that bridges from asperity scale to wafer scale. We then derive a fundamental basis for CMP removal rate prediction based on contact and hydrodynamics, using a Sommerfeld number defined across the groove and texture length scales. The resulting equation, containing a single unknown proportionality constant, demonstrates that the often used product of downforce and table speed tracks removal rate only when the hydrodynamic state affords adequate pad-wafer contact. Departures from the Preston equation attributed in other models to chemically-limited regimes of CMP are explained in the present treatment as changes in hydrodynamic film thickness and contact area—a fact confirmed by direct measurement. Removal rate predictions are discussed for ILD, STI, and copper processes using both conventional and non-Prestonian slurries, including variations in downforce, table speed, temperature, pad properties, and groove design. Finally, the influence of regional pad-wafer hydrodynamics is illustrated by applying the contact-hydrodynamics equation to grooves specially configured to vary the slurry film thickness from wafer center to edge. Local removal rates are well predicted using locally defined values of the groove-texture Sommerfeld number, confirming the generality of the contact-hydrodynamic description at least from wafer to asperity scale. Findings are further discussed in the context of next-generation pad architectures—not only to achieve more effective pad-wafer contact and slurry delivery, but also to favorably decouple contact and fluid mechanics in CMP pad design.
Surfactants in Controlling Removal Rates and Selectivity in Barrier Slurry for Cu CMP
Authors: Bian Jinru 
Published: April 2011

ABSTRACTLeading edge integrated circuits (ICs) are complicated structures designed to have up to 3 capping layers above a low k dielectric material. The upper capping layer may use TEOS and/or silicon nitride (SiN), while the lower one may use silicon carbon nitride (SiCN), silicon carbide (SiC), or carbon doped oxide (CDO) immediately above the low k dielectric. Therefore, a barrier slurry for copper CMP, in addition to exhibiting a high removal rate of the barrier, must be able to remove the upper capping layer and stop at the underlying dielectric surface.We have developed a slurry family that can effectively remove TaN, TEOS, SiN, CDO, and/or SiCN, or any combination of these films, or can stop at any one or two film surfaces of TEOS, SiN, CDO, SiCN, and SiC, depending on the specific slurry design. Removal rate control is achieved by one or two additives. One of the additives is an anionic surfactant. When selecting a surfactant, the surfactant hydrophobicity and charge interaction between the surfactant and the wafer surface are two important factors to be considered. This report discusses these two factors in selecting a proper surfactant for a specific slurry application.
Defect Structures of B12As2 Epilayers Grown on c-plane and a-plane 6H-SiC Substrates
Authors: Chen Hui , Wang Guan , Dudley Michael , Zhang Lihua , Zhu Yimei , Zhang Yi , Edgar James H. , Kuball Martin 
Published: April 2011

AbstractB12As2 epitaxial layers grown on (0001) 6H-SiC and (1120) 6H-SiC substrates have been studied using scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and synchrotron white beam x-ray topography (SWBXT) and investigated with the aid of crystal visualization software. SWBXT showed that B12As2 adopted [111] growth orientation, parallel to [0001]SiC, on c-plane 6H-SiC and adopted [101] growth orientation, parallel to [1120]SiC, on a-plane 6H-SiC. However, SWBXT also revealed the twins in both sets of the B12As2 films, consistent with the SEM observation of the surface morphology. Cross-sectional HRTEM also confirmed the presence of twins in both cases and also revealed the existence of an intermediate layer between the c-plane 6H-SiC and the B12As2 film. By correlating the HRTEM observation and crystal visualization, the atomic configurations across the twin boundaries in both samples as well as those in the intermediate layer in the c-plane sample were proposed.
Lead Iodide Thin Films Grown Using N.N-Dimethylformamide as Solvent
Authors: Fernando Condeles Jose , Caldeira-Filho Ademar Marques , Mulato Marcelo 
Published: April 2011

AbstractSpray pyrolysis was used for the deposition of lead iodide (PbI2) thin films using N.N-dimethylformamide (DMF) as an alternative solvent under varying deposition parameters. Final thickness of 60 μm was obtained for a total deposition time of 2.5 hours. The films were characterized mainly by using Raman and photoluminescence, but additional techniques such as X-ray diffraction, scanning electron microscopy and dark conductivity as a function of temperature were also employed. Thick PbI2 films deposited by spray pyrolysis using DMF as a solvent are promising to be used in medical systems as X-ray imaging.
Comparison of Silicon Photoluminescence and Photoconductive Decay for Material Quality Characterization
Authors: Johnston Steven , Ahrenkiel Richard , Dippo Pat , Page Matt , Metzger Wyatt 
Published: April 2011

AbstractMinority-carrier lifetime in silicon directly relates to defect- and impurity-related recombination, and thus gives a measure of material quality. Lifetime measurements are useful in research laboratories and commercial production environments as an indicator for process development and quality control. While photoconductivity (PCD) techniques for measuring lifetime are commercially available, there has recently been interest in using photoluminescence (PL) to characterize lifetime in silicon because of the measurement speed to image an entire wafer and higher mapping resolution. The intensity of band-to-band PL is theoretically proportional to the effective bulk lifetime in low-injection conditions if carrier diffusion and re-absorption are neglected, surface recombination is small, and silicon properties, such as carrier concentration and the radiative recombination coefficient, are constant. We show data that compare lifetimes from PCD techniques to PL intensity for varying-resistivity, single-crystal silicon. Surface conditions are also varied (native oxide, thermal oxide, and HF etch/methyl-iodine solution), and the measured lifetimes are compared to corresponding PL intensity.
Characterization of the Segregation of Arsenic at the Interface SiO2/Si
Authors: Steen Christian , Pichler Peter , Ryssel Heiner , Pei Lirong , Duscher Gerd , Werner Matt , van den Berg Jaap A. , Windl Wolfgang 
Published: April 2011

AbstractThe segregation of As atoms at the Si/SiO2 interface during annealing was investigated by grazing incidence X-ray fluorescence spectroscopy in combination with successive removal of silicon layers by etching with thicknesses on the order of a nanometer. With this method it is possible to clearly distinguish between the segregated atoms and the As atoms in the bulk over a large range of implantation doses from 3·12 cm−2 to 1·16 cm−2. The samples were annealed at 900 °C and 1000 °C, respectively, for times sufficiently long to ensure that the segregation reflects an equilibrium effect. The results were confirmed by medium energy ion scattering, Z-contrast measurements and electron energy loss spectroscopy.
An Experimental and Simulation Study of Arsenic Diffusion Behavior in Point Defect Engineered Silicon
Authors: Kong Ning , Kirichenko Taras A. , Hwang Gyeong S. , Mark Foisy C. , Anderson Steven G. H. , Banerjee Sanjay K. 
Published: April 2011

AbstractWe report that arsenic diffusion can be enhanced and retarded by surrounding interstitial rich and vacancy rich environments created by Si point defect engineering implant. The enhancement and retardation can be attributed to the dominant arsenic interstitial diffusion mechanism during post-implant anneal. Kinetic Monte Carlo simulations with newly implemented models show good match with experiments. Our study suggests the importance of arsenic interstitial mechanism and a possible approach for n-type ultra shallow junction fabrication.
Silver Nanocrystals at Cavities Created by High Energy Helium Implantation in Bulk Silicon
Authors: El Bouayadi Rachid , Regula Gabrielle , Lancin Maryse , Larios Eduardo , Pichaud Bernard , Ntsoenzok Esidor 
Published: April 2011

AbstractHigh resolution transmission electron microscopy observations show for the first time the presence of two orientations of pure silver precipitates in nanocavities induced in bulk silicon by implantation at 1.6 MeV with a dose of 5×1016 He+ cm−2 and a two hour annealing at 1050°C. These precipitates were called A and B to refer to the two well-known nickel silicide (NiSi2) precipitates or Ag films on a {111} silicon surface. Thus, the A precipitate corresponds to a growth of silver nanocrystal on {111} cavity walls in epitaxy with the Si matrix with an orientation relationship Ag(-111)[211]||Si(-111)[211]. The B precipitate develops on a {111} plane parallel to a {111} cavity wall as well, but in a twin orientation with respect to the Si matrix defined by Ag(-111)[211]||Si(-111)[-2-1-1]. The Ag nanocrystals have a size ranging from a few nm to 50 nm. Most of them have the faceted-shape characteristic of “clean” cavities. They are either A precipitates or they contain alternatively A and B bands in good agreement with both the low stacking fault energy of silver and the two types of nanocrystal orientations obtained by Ag deposition on (111) Si substrate at room temperature. Some Ag precipitates were also found at dislocations located at the He+ projection range, but these trapping sites were found thermally unstable as compared to the cavity ones. Indeed, during a second identical annealing, the precipitates grow in cavities whereas they fade at dislocations.
Microwave Activation of Exfoliation in Ion–cut Silicon Layer Transfer
Authors: Thompson Douglas C. , Alford T. L. , Mayer J. W. , Hochbauer T. , Lee J. K. , Nastasi M. , Theodore N. David 
Published: April 2011

AbstractMicrowave heating is used to initiate the ion-cut process for transfer of coherent silicon-layers onto insulator substrates. Hydrogen and boron co-implanted silicon was bonded to an insulative substrate before processing inside a 2.45 GHz, 1300 W cavity applicator microwave system. Sample temperatures measured using a pyrometer were comparable to previous ion – cut studies. Selected samples were further annealed to repair any damage created in the ion implant process. Rutherford backscattering spectrometry and selective area electron diffraction patterns show high crystallinity in transferred layers. RUMP simulation of backscattering spectra and cross-sectional transmission electron microscopy demonstrate that thicknesses of the transferred layers are comparable to previous ion-cut exfoliation techniques. Surface quality as characterized by an atomic force microscope compares well with previous ion-cut studies. Hall measurements were used to characterize electrical properties of transferred layers. The mobility and carrier density of microwave activated ion – cut silicon on insulator processed samples compares well with previous annealing techniques.
The Charge Carriers Transport Mechanism Through the Interface Layer of the p-GaSe(Cu)/n+GaAs Heterojunctions
Authors: Cuculescu Elmira I. , Caraman Mihail I. 
Published: April 2011

AbstractThe photoelectrical properties of p-GaSe(Cu)/n-GaAs heterojunctions obtained by optically contacting the components and by thermal evaporation of GaSe, have been studied. The rectification factor for optically contacted heterojunctions is ∼2·102 at 5 V, and the current flow is determined by diffusion mechanism. The diffusion and recombination through the interface defects mechanisms determine de current flow for heterojunctions formed by GaSe evaporation.
Design and Simulation of High Efficiency Silicon Light-Emitting Diodes
Authors: Pan Grant Z. , Peretzman Jaime , Pak Dae H. , Ren Li P. 
Published: April 2011

AbstractFour boron-implanted p-n junction silicon light-emitting diode structures were designed and simulated under an identical process flow by using Silvaco simulators. In the simulation, only boron-implant parameters and post-implant anneal conditions were varied to identify and compare the physical, electrical, and optical properties of the structures. It was found that a pillar structure with a wrapped p-n junction has the greatest radiative recombination rate. Regardless the structure type, the maximum radiative recombination rate always occurs within the p+ region. There exists a peak in the maximum radiative recombination rate when the anneal temperature increases from 700 to 1100 °C, and the anneal temperature at peak increases while the implant dose increases. Furthermore, the radiative recombination rate always increases with the implant dose but it saturates at a high dose. However, the radiative recombination rate does not change significantly with the implant energy.
Bright-Pixel Defects in Irradiated CCD Image Sensors
Authors: McColgin William C , Tivarus Cristian , Swanson Craig C. , Filo Albert J. 
Published: April 2011

AbstractWe have examined environmental radiation sources for digital cameras to find the origins of bright-pixel defects known to accumulate with time. We show that beta and gamma emissions from camera parts and lenses cause image transients, but permanent damage can occur with alpha particles from the CCD cover glass. Our experiments with 14-MeV- and thermal-neutron beams confirm that cosmic rays are the primary cause of new imager bright points.