bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU-8 Processing on a Variety of Substrates
Authors: Chiang Yuh-Min , Bachman Mark , Chang Hung-Pin , Chu Charles , Li G. P. 
Published: April 2011

AbstractSU-8 has become a popular material for micromachining high aspect ratio structures. Typically, SU-8 is spun on a polished silicon wafer for processing. After patterning, the SU-8 is used for micromachined structures directly (such as fluidic channels) or as a mold for electroforming. Non-silicon substrates offer the possibility of cheaper processing, improved mold designs, and multi-material devices. Successful SU-8 processing depends strongly on surface properties of the substrate itself as well as environmental conditions during the processing. We explore the issues involved in transferring SU-8 technology to non-silicon substrates such as glass, plastics and metals. Issues such as wettability, adhesion, and surface tension are explored in this study. The findings indicate the merits of non-spinning approaches, such as dipping, spraying, and brushing and point to new SU-8 processes.
Metal Organic Chemical Vapor Deposition of Co-, Mn-, Co-Zr and Mn-Zr Oxide Thin Films
Authors: Barreca D. , Benetollo F. , Bozza M. , Bozza S. , Carta G. , Cavinato G. , Rossetto G. , Zanella P. 
Published: April 2011

AbstractDeposition of thin films of Co- and Mn- oxides as well as of their mixtures with ZrO2 have been carried out by MOCVD using Co(C5H5)2, Mn(C5F6HO2)2(THF)2and (C5Hs)2Zr(CH3)2as precursors. XRD and XPS analyses of the obtained deposits are reported. Introduction of water vapor into the reactor chamber during the flow of the precursors improved their decomposition efficiency and the quality of the films.
Auger Suppression in and Noise Performance of “Hot” HgCdTe IR Detectors
Authors: Benjaminsen F. , Rheenen A. D.van , Chen X.-Y. 
Published: April 2011

AbstractThe carrier concentration in narrow-gap semiconductors operating at room temperature is usually determined by thermal generation, not by doping. By reverse biasing a specially designed HgCdTe P+ - π - N+ heterostructure, the carrier concentrations in the narrow-gap π layer are held below the intrinsic concentration. Temperature dependent measurements of the reverse-bias current-voltage characteristics reveal that the devices operate as "usual" diodes below approximately 225 K. Above this temperature, the intrinsic carrier concentration increases, and the suppression mechanism appears in the I-V curves as negative differential resistance regions. The low-frequency noise performance of these devices, both in the forward bias and the reverse bias regime, as a function of temperature will be presented.
The Growth of InAsSb/InAs/InPSb/InAs Mid-Infrared Emitters by Metal-Organic Chemical Vapor Deposition
Authors: Biefeld R. M. , Phillips J. D. , Kurtz S. R. 
Published: April 2011

AbstractWe report on the metal-organic chemical vapor deposition (MOCVD) of strained layer superlattices (SLSs) of InAsSb/InAs/InPSb/InAs as well as mid-infrared optically pumped lasers grown using a high speed rotating disk reactor (RDR). The devices contain AlAsSb cladding layers and strained, type I, InAsSb/InAs/InPSb/InAs strained layer superlattice (SLS) active regions. By changing the layer thickness and composition of the SLS, we have prepared structures with low temperature (<20K) photoluminescence wavelengths ranging from 3.4 to 4.8 µm. The optical properties of the InAsSb/InPSb superlattices revealed an anomalous low energy transition that can be assigned to an antimony-rich, interfacial layer in the superlattice. This low energy transition can be eliminated by introducing a 1.Onm InAs layer between the InAsSb and InPSb layers in the superlattice. An InAsSb/InAs/InPSb/InAs SLS laser was grown on an InAs substrate with AlAs0.16Sb0.844cladding layers. A lasing threshold and spectrally narrowed laser emission were seen from 80 through 250 K, the maximum temperature where lasing occurred. The temperature dependence of the SLS laser threshold is described by a characteristic temperature, T0 = 39 K, from 80 to 200 K.
Control of the Intermixing of InGaAs/InGaAsP Quantum Well in Impurity Free Vacancy Disordering by Changing NH3 Flow Rate During the Growth of SiNx Capping Layer
Authors: Choi W.J. , Yi H.T , Woo D.H. , Lee S. , Kim S.H. , Kang K.N. , Cho J. 
Published: April 2011

AbstractThe dependence of impurity free vacancy disordering (IFVD) of InGaAs/InGaAsP QW structure on the characteristics of dielectric capping layer was studied using SiNx film as capping layers. The characteristics of the SiNx capping layer were varied by changing the NH3 flow rate during SiNx deposition by plasma enhanced chemical vapor deposition (PECVD). The degree of quantum well intermixing (QWI) with SiNX capping layer grown at higher NH3 flow rate was larger than that with SiNx film grown at lower NH3 flow rate. This implies that QWI can be easily controlled by simply changing the reactive gas ratio in the growing process of SiN, capping layer. It was also shown that this method to control QWI is better than the method of using two different capping layers such as SiNx film and SiO2 film in order to get spatially selective QWI on the same substrate.
Theoretical and Experimental Investigation of Disordering Effects on Photoluminescence Spectra of InGaAs/InGaAsP Quantum Wells
Authors: Yi J. C. , Choi W. J. , Lee S. , Woo D.H. , Kim S. H. 
Published: April 2011

AbstractThe effect of disordering on photoluminescence spectra of InGaAs/InGaAsP quantum wells has been investigated experimentally and theoretically taking into account the valence band intermixing, strain, exciton effects, and the non-identical diffusion constants for group III and V materials. The disordering profile of 1.55Q InGaAs/InGaAsP quantum wells lattice matched to InP has been controlled by choice of the cap layer materials as well as the diffusion time and diffusion temperature. By comparing the experimental data and theoretical calculations, the diffusion constant for each material has been extracted.
Photoluminescence of Eu3+ in Si/SiO2 Nanostructure Films
Authors: Liu Huimin , Mahfoud Aziz , Nery G. A. , Resto O. , Fonseca Luis F. , Weisz Zvi S. 
Published: April 2011

ABSTRACTEu3+ -doped Si/SiO2 nanocomposites were successfully prepared by Ar sputtering deposition on quartz substrates. The optical properties were studied using time-resolved photoluminescence spectroscopy. Excited by intense picosecond laser pulses with energy greater than1GW/cm2 and wavelength at 532nm the observed photoluminescence consists of a rapidly decaying component with life time of ∼1 s and a slowly component with life time of ∼ 2 ms. The former was recognized as coming from Si/SiO2 nanostructures matrix while the latter as coming from the impurity Eu3+ ions. Using the intense laser excitation a two-photon absorption by silicon matrix occurred, resulting in photo-induced carriers produced in conduction band. A direct recombination from Si/SiO2 nanostructure host gives a weak but fast emission, and creates a large number of nonequilibrium phonon. For Eu3+ emission a set of 5D0 to 7F multiplet transitions were identified. In addition to the direct excitation by 532nm the excited state 5D0 of Eu3+ ions was also found to be populated due to energy transfer from silicon matrix. The mechanism of phonon-assisted energy transfer is discussed.
Non Linear Optical Gain in Bulk Barrier Amorphous Silicon Phototransistor
Authors: Caputo D. , de Cesare G. , Nascetti A. , Palma F. 
Published: April 2011

ABSTRACTIn this work we report studies on the non linear dependence of the optical gain with the incident power in an amorphous silicon bulk barrier phototransistor based on a n-i-p-i-n structure. The optical gain shows a quasi-hyperbolic dependence on the illumination intensity. The non-linear behavior was predicted by an analytical device model which takes into account the properties of both material and structure, which lead to the amplification mechanism of the device.
Amorphous Crystalline Silicon Heterojunction with Silicon Nitride Buffer Layer
Authors: Claudio G. , Rosa R. De , Roca F. , Caputo D. , Tucci M. 
Published: April 2011

ABSTRACTIn this work we study the possibility to use amorphous silicon nitride, grown by plasma, as an alternative way to realize buffer layer in a-Si:H/c-Si heterostructure. We experimented several growing condition for silicon nitride depending on deposition parameters, obtaining samples highly transparent and with optical gap varying in the range 2.4 – 5.2 eV. We found evidence that the gap of the material is principally due to the NH3/N2 ratio. The very low absorption obtainable on this material was successfully utilized to increase the short circuit current density of the device respect to the standard cell with intrinsic amorphous silicon buffer, particularly in the low wavelength region as confirmed by quantum yield measurements. We optimized the thickness of the SiNx buffer layer respect to the photovoltaic parameters of the solar cell. A 0.5 nm thick SiNx ensures good photogeneration in blue region of the visible spectrum and does not appreciably degrade the transport mechanism of the heterojunction.
Amorphous Silicon Microbolometer Technology
Authors: Syllaios A. J. , Schimert T. R. , Gooch R. W. , McCardel W. L. , Ritchey B. A. , Tregilgas J. H. 
Published: April 2011

ABSTRACTHighly sensitive hydrogenated amorphous silicon (a-Si:H) microbolometer arrays have been developed that take advantage of the high temperature coefficient of resistance (TCR) of aSi:H and its relatively high optical absorption coefficient. TCR is an important design parameter and depends on material properties such as doping concentration. Ultra-thin (∼2000 Å) aSiNx:H/a-Si:H/ a-SiNx:H membranes with low thermal mass suspended over silicon readout integrated circuits are built using RF plasma enhanced chemical vapor deposition (PECVD) and surface micromachining techniques. The IR absorptance of the bolometer detectors is enhanced by using quarter-wave resonant cavity structures and thin-film metal absorber layers. To ensure high thermal isolation the microbolometer arrays are vacuum packaged using wafer level vacuum packaging. Imaging applications include a 120×160 a-Si:H bolometer pixel array IR camera operating at ambient temperature. Non-imaging applications are multi-channel detectors for gas sensing systems.
Si-H Vibration Only at 2000 CM-1 in Fully Polycrystalline Silicon Films Made by Hwcvd
Authors: Rath J.K. , Schropp R.E.I. 
Published: April 2011

ABSTRACTThe Si-H vibration in IR spectra of our device quality poly-Si films grown by hot-wire chemical vapour deposition (HWCVD) made at low wire temperature (Tw=1800 °C) is at 2000 cm−1 whereas in a poly-Si film made at high wire temperature (Tw=1900 °C) both 2000 cm−1 vibrations as well as 2100 cm−1 are observed. On the other hand, the Raman spectra (probing the upper part of the film) of Si-H stretching vibration measured for both these samples show only 2000 cm-1 mode. XTEM micrographs of these films show that whereas the low Tw film has a structure made of closely packed crystalline columns, the high Tw film has conical crystalline structures with amorphous region between them. The crystal cones meet each other towards the top of the film and form a closed structure. This is confirmed by Raman spectrum at 520 cm−1. We attribute the 2100 cm−1 mode to the Si-H bonds at the surface of the cones touching the amorphous regions. The Si-H vibration shifts to 2000 cm-1 when the crystalline cones coalesce with each other, as is the case in the upper part of both types of films.
Modeling of Beta Conductivity in Tritiated Amorphous Silicon
Authors: Costea Stefan , Gaspari Franco , Kosteski Tome , Zukotynski Stefan , Kherani Nazir P. , Shmayda Walter T. 
Published: April 2011

ABSTRACTThe change with time in the electrical conductivity of a hydrogenated-tritiated amorphous silicon film (a-Si:H:T) has been studied. The conductivity decreased with time after deposition. A model is developed to account for the decrease. The radioactive decay of tritium into helium produces energetic beta particles. Each β particle creates over 1500 electron-hole pairs in the film thereby increasing the conductivity of the film. The 3He atoms diffuse away leaving dangling bonds behind. We find that neutral dangling bonds (D0) are responsible for the decrease in conductivity by acting as recombination centers in the material.
Laser Processing of Amorphous Silicon for Polysilicon Devices, Circuits and Flat-Panel Imagers
Authors: Boyce J. B. , Fulks R. T. , Ho J. , Lu J. P. , Mei P. , Street R. A. , Schuylenbergh K. F. Van , Wang Y. 
Published: April 2011

ABSTRACTPulsed excimer-laser processing of amorphous silicon on non-crystalline substrates allows for the fabrication of high-quality polysilicon thin-film transistors (TFTs). It also provides procedures for doping self-aligned amorphous silicon TFTs. In addition, laser-crystallized polysilicon exhibits some interesting materials properties, such as, large lateral grain growth with a corresponding enhancement in the electron mobility. Under optimized processing conditions, excellent polysilicon TFTs with high mobilities, sharp turn on, low off-state leakage currents and good spatial uniformity have been achieved. These improved parameters, particularly the low off-state leakage currents and good uniformity, enable not only displays but also the moredemanding flat-panel imaging arrays to be fabricated in polysilicon. Results on both polysilicon CMOS circuits and a polysilicon flat-panel imager are presented.
Methods of Suppressing Cluster Growth in Silane RF Discharges
Authors: Shiratani Masaharu , Maeda Shinichi , Matsuoka Yasuhiro , Tanaka Kenichi , Koga Kazunori , Watanabe Yukio 
Published: April 2011

ABSTRACTThe effects of gas temperature gradient, pulse discharge modulation, hydrogen dilution, gas flow, and substrate materials on growth of clusters below about 10 nm in size in silane parallelplate RF discharges are studied using a high-sensitivity photon-counting laser-light-scattering (PCLLS) method. Thermophoretic force due to the gas temperature gradient between the electrodes drives neutral clusters above a few nm in size toward the cool RF electrode. Pulse discharge modulation is much more effective in reducing the cluster density when it is combined with the gas temperature gradient, and clusters above a few nm in size cannot be detected by the PCLLS method even for the discharge over a few hours. Hydrogen dilution and gas flow are also effective in suppressing growth of clusters, when the H2/SiH4 concentration ratio is above about 5 and the flow velocity is above about 6 cm/s, respectively. Cluster growth rate with a glass or Si substrate is found to be considerably higher than that without the substrate.
Effect of Hydrogen Radical on Properties of Hydrogen in Hydrogenated Microcrystalline Silicon
Authors: Itoh Takashi , Yamana Noriyuki , Inouchi Hiroki , Yoshida Norimitsu , Harada Hidekuni , Kondo Hiroaki , Yamamoto Kanta , Nonomura Shuichi , Nitta Shoji 
Published: April 2011

ABSTRACTHydrogenated microcrystalline silicon (μc-Si:H) films are prepared by hot-wire assisted plasma enhanced chemical vapor deposition, which controls the hydrogen radical density by filament temperatures, Tf, without changing other conditions. The effect of hydrogen radical on the properties of incorporated hydrogen into μc-Si:H films is studied using infrared absorption and gas effusion spectroscopies. The hydrogen concentration decreases with increasing Tf. The crystalline volume fraction, Xc, increases with Tf and shows a peak at Tf of 1850 °C. Integrated intensities of the modes near 2000 and 2100 cm-1 decrease with increasing Tf. Integrated intensity of the mode near 880 cm-1 shows almost same tendency of Xc. The effect of hydrogen radical on the properties of incorporated hydrogen into μc-Si:H films is discussed.
Control of Amorphous Silicon Crystallization Using Germanium Deposited by Low Pressure Chemical Vapor Deposition
Authors: Toita Masato , Kalavade Pranav , Saraswat Krishna C. 
Published: April 2011

ABSTRACTCrystallization behavior of 100nm amorphous silicon film with and without a 160nm poly-Ge layer on top was investigated. Ge was observed to increase the nucleation rate as well as to increase the incubation time for nucleation in a-Si. Activation energy for nucleation was 2.3eV for Ge-covered Si films as compared to 2.7eV for the control a-Si films with no poly-Ge. Activation energy for incubation is almost unchanged for both the films (-3.3eV). An alternative seeding technique for a-Si films using the increase in the incubation time for nucleation due to presence of poly-Ge is proposed.
A Percolative Approach to Electromigration Modelling
Authors: Pennetta C. , Reggiani L. , Trefán Gy. , Fantini F. , Scorzoni A. , DeMunari I. 
Published: April 2011

AbstractWe present a stochastic model which simulates electromigration damage in metallic interconnects by biased percolation of a random resistor network. The main features of experiments including Black's law and the log-normal distribution of the times to failure are well reproduced together with compositional effects showing up in early stage measurements made on Al-0.5%Cu and Al-1%Si lines.
Study of SiH4-based PECVD Low-k Carbon-doped Silicon Oxide
Authors: Yang Hongning , Tweet Douglas J. , Stecker Lisa H. , Pan Wei , Evans David R. , Hsu S.-T. 
Published: April 2011

AbstractIn previous studies, low-k carbon-doped silicon oxide (SiOC) films were deposited using organosilicon precursor: (CH3)xSiH4−x. In this paper, we present the properties of PECVD low-k SiOC films produced by using conventional SiH4 based gas precursors. The SiH4 based SiOC films have similar gross physical and electrical characteristics to those of (CH3)xSiH4−x based SiOC. Since the precursors are inexpensive, commercially available and convenient to operate for existing tools, the process should not require additional cost as compared with that of PECVD silicon dioxide. We demonstrate the feasibility of integrating Cu with SiOC on damascene interconnection. The evaluation on electrical performance of the Cu/SiOC based damascene structure will be discussed.
Backside Copper Contamination Issues in CMOS Process Integration – A Case Study
Authors: Prasad K. , Tee K.C. , Chan L. , See A. K. 
Published: April 2011

AbstractNMOS and PMOS transistors of various (W/L) ratios, down to 0.24µm channel length, have been used to investigate the effects of copper diffusion (from the backside) on their electrical parameters. A thin layer of copper film was deposited on the back surface of the wafer. Over 10 hours of annealing at 4000C was carried out. Electrical parameters such as the threshold voltage (VT0), the drain saturation current (IDsat) and the off-current (Ioff), for transistors, and the leakage current for large diodes were measured. Secondary Ion Mass Spectroscopy (SIMS) was used to monitor the copper diffusion. Even after 10 hours of annealing at 400°C, electrical parameters of both NMOS and PMOS devices and leakage currents of diodes showed no significant degradation.
The Integration of Low-k Dielectric Material Hydrogen Silsesquioxane (HSQ) with Nitride Thin Films as Barriers
Authors: Zeng Yuxiao , Chen Linghui , Alford T. L. 
Published: April 2011

AbstractHSQ (hydrogen silsesquioxane) is one of the promising low-k materials used in VLSI technology as an intra-metal dielectric to reduce capacitance-related issues. Like any other dielectrics, the integration of HSQ in multilevel interconnect schemes has been of considerable importance. In this study, the compatibility of HSQ with different nitride barrier layers, such as PVD and CVD TiN, PVD TaN, and CVD W2N, has been investigated by using a variety of techniques. The refractory metal barriers, Ti and Ta, are also included for a comparison. The degradation of HSQ films indicates a strong underlying barrier layer dependence. With CVD nitrides or refractory metals as barrier, HSQ exhibits a better structural and property stability than that with PVD nitrides. The possible mechanisms have been discussed to account for these observations.
Energetic Inert Gas Atom Impact Effects During Ion Beam Multilayer Deposition
Authors: Zhou X. W. , Zou W. , Wadley H. N. G. 
Published: April 2011

AbstractNew magnetic field sensors and non-volatile magnetic random access memories can be built from giant magnetoresistive multilayers with nanoscale thickness. The performance of these devices is enhanced by decreasing the atomic scale interfacial roughness and interlayer mixing of the multilayers. During ion beam sputtering, inert gas neutrals with energies between 50 and 200 eV impact the growth surface. A molecular dynamics method has been used to study the effects of these impacts on the surface roughness and interlayer mixing of model nickel/copper multilayers. The results indicate that impacts with energy above 50 eV cause mixing due to the exchange of Ni atoms with Cu atoms in an underlying Cu crystal. The extent of the mixing increases with impact energy, but decreases as the number of the Ni monolayers above the Cu crystal increases. While Xe and Ar impacts have a similar mixing effect at low energies, heavier Xe ions/neutrals induce more significant mixing at high energies.
Diamond CVD Growth Mechanisms and Reaction Rates From First-Principles
Authors: Oleinik I.I , Pettifor D.G. , Sutton A.P. , Battaile C.C. , Srolovitz D.J. , Butler J.E. , Dandy D.S. , Harris S.J. , D'evelyn M.P. 
Published: April 2011

AbstractCVD diamond is an enabling material for diverse applications. In recent years, multiscale modelling of CVD growth in conjunction with experimental studies of the deposition processes has made a substantial progress towards our understanding of the fundamental growth chemistry and material quality. Macroscopic gas phase simulations of the CVD reactor, the mesoscale kinetic Monte-Carlo (KMC) modelling of the crystal growth and nanoscale modelling of the surface chemistry are three main legs in the multiscale hierarchy. In the framework of this methodology we have performed first-principles quantum mechanical calculations of bonding and reaction kinetics of the elementary growth processes and provided critical input in the form of atomistic growth mechanisms and reaction rates for the mesoscale KMC modelling of CVD diamond growth. A key success was achieved by combining first-principles and Monte Carlo studies to elucidate (100) growth mechanisms that have perplexed the diamond growth community for many years.