bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Processes during Growth of Hydrogenated Amorphous Silicon
Authors: Aydil Eray S. , Agarwal Sumit , Valipa Mayur , Sriraman Saravanapriyan , Maroudas Dimitrios 
Published: April 2011

ABSTRACTHydrogenated amorphous silicon films for photovoltaics and thin film transistors are deposited from silane containing discharges. The radicals generated in the plasma such as SiH3 and H impinge on the surface and lead to silicon film growth through a complex network of elementary surface processes that include adsorption, abstraction, insertion and diffusion of various radicals. Mechanism and kinetics of these reactions determine the film composition and quality. Developing deposition strategies for improving the film quality requires a fundamental understanding of the radical-surface interaction mechanisms. We have been using in situ multiple total internal reflection Fourier transform infrared spectroscopy and in situ spectroscopic ellipsometry in conjunction with atomistic simulations to determine the elementary surface reaction and diffusion mechanisms. Synergistic use of experiments and atomistic simulations elucidate elementary processes occurring on the surface. Herein, we review our current understanding of the reaction mechanisms that lead to a-Si:H film growth with special emphasis on the reactions of the SiH3 radical.
Roughness evolution of high-rate deposited a-SiNx:H films studied by atomic force microscopy and real time spectroscopic ellipsometry
Authors: Oever P.J. van den , Sanden M.C.M. van de , Kessels W.M.M. 
Published: April 2011

ABSTRACTThe scaling behavior of the roughness evolution of silicon nitride (a-SiNx:H) films with different mass densities (deposited from SiH4-N2-H2 and SiH4-NH3 based plasmas) has been investigated by atomic force microscopy and real time spectroscopic ellipsometry. The observed roughness exponent a is similar for both films, whereas the growth exponent b is a factor of two smaller for the higher density films. The relation between the lower value of b and the higher mass density is discussed.
Low-Temperature Silicon Films Deposition by Pulsed Cathodic Arc Process for Microsystem Technologies
Authors: Xia Hui , Yang Yan , Bergstrom Paul L. 
Published: April 2011

ABSTRACTThe deposition of silicon films was investigated for the first time by the pulsed cathodic vacuum arc process. This method has been employed to take the advantages of its low deposition temperature, high deposition rate, and high-energy capabilities, coupled with its relatively low operational cost. Heavily doped silicon films were deposited on silicon and glass substrates at temperatures below 100°C with pulsed deposition rate of 0.2nm/A·s. Pulsed arc currents up to 400A in 1∼5ms pulse width with 20∼300 pulses per second were studied. Compared with the direct current (D.C.) cathodic vacuum arc, numerous possibilities exist for the pulsed arc deposition to suit specific targeted film growth. The characterization of the films was carried out by scanning electron microscopy (SEM) and X-ray diffraction (XRD) in terms of materials morphological and structural properties. The production of high quality silicon film materials at low temperature would further enable the integration of microsystems with microelectronics.
Correlation of Hydrogenated Nanocrystalline Silicon Microstructure and Solar Cell Performance
Authors: Wang Keda , Canning Anthon , Weinberg-Wolf J.R. , Harley E.C.T. , Han Daxing , Yan Baojie , Yue Guozhen , Yang Jeffrey , Guha Subhendu 
Published: April 2011

ABSTRACTWe used Raman and photoluminescence (PL) spectroscopy to study the relationship between the material properties and the solar cell performance of hydrogenated nanocrystalline silicon (nc-Si:H). The crystalline volume fraction (fc) was deduced from the Raman spectrum. Generally, a high fc leads to a high short circuit current density and a low open circuit voltage. PL spectra were measured using 632.8-nm and 442-nm laser lines. There are two distinguished PL peaks at 80 K, one at ∼1.4 eV originating from the amorphous region, while the other at = 0.9 eV from the nanocrystalline grain boundary regions. Generally, the intensity fraction of this low energy PL peak, IPLc/(IPLa+IPLc), was larger for 442-nm than 632.8-nm excitation, indicating an increase in crystallinity along the growth direction. However, for the best initial performance cells obtained by H2 dilution profiling and the i/p buffer layer, the intensity fraction IPLc/(IPLa+IPLc) decreased from the bulk to the topi/p interface. The Raman and PL results give insight into the correlation between the microstructures and the cell performance, and verified that properly-controlled crystallinity in the intrinsic layer and buffer layer at the i/p interface layer are important for optimizing nc-Si:H solar cells.
Doping and Mobility Profiles in Defect-Engineered Ultra-shallow Junctions: Bulk and SOI
Authors: Smith A. J. , Colombeau B. , Gwilliam R. , Collart E. , Cowern N.E.B. , Sealy B. J. 
Published: April 2011

ABSTRACTSilicon on insulator (SOI - Smartcut®) wafers were implanted with 1MeV and 300keV silicon ions to doses of 3.8x1015 cm−2 and 3x1014 cm−2, respectively, in order to modify the vacancy concentration in a controlled way. Boron was then implanted at 2keV to a dose of 1×1015 cm−2 into the near-surface part of the vacancy-engineered region. Atomic profiles were determined using SIMS and electrical profiles were measured using a novel Differential Hall Effect (DHE) technique, which enables profiling of electrically active dopants with a nanometer depth resolution. The electrical profiles provide pairs of carrier concentration and mobility values as a function of depth. The buried oxide (BOX) is proven to restrict the back diffusing interstitials positioned below the BOX from entering the silicon top layer and interacting with the boron profile. Also an increase of ∼50% in boron activation is achieved when a co-implant is used. However, SOI shows a reduced degree of activation when compared to bulk silicon, with or without a co-implant.
Post-Anneal Stress Reduction of 200 mm Silicon Wafers in Single Wafer Rapid Thermal Annealing
Authors: Setokubo Tsuyoshi , Nakano Eiichi , Aizawa Kazuo , Miyoshi Hidekazu , Yamamoto Jiro , Fukada Takashi , Yoo Woo Sik 
Published: April 2011

ABSTRACTIn every wafer processing step wafer stress management is extremely important for advanced device manufacturing. Thermally induced stress on device wafers has a large impact on lithography and affects device yield. Thermally induced stress during rapid thermal annealing (RTA) steps in high density 512MB DRAM device fabrication was investigated using a lamp-based (cold wall) RTA system and compared to results using a furnace-based (hot wall) single wafer RTA system. Compared to the lamp-based (cold wall) system, RTA in a furnace-based (hot wall) system was found to be very effective in suppressing thermally induced stress and increasing device yield due to superior pattern transfer characteristics in lithography.
Modeling Atomistic Ion-Implantation and Diffusion for Simulating Intrinsic Fluctuation in MOSFETs arising from Line-Edge Roughness
Authors: Hane Masami , Ikezawa Takeo , Ezaki Tatsuya 
Published: April 2011

ABSTRACTWe have developed new simulation tools to enable more precise design of sub-100nm MOSFETs. Intrinsic fluctuations in the characteristics of these devices occur as part of their statistical nature. Our three-dimensional atomistic approach to both process and device simulations enabled us to examine the coupling effects of the most significant sources of fluctuation, i.e.line-edge-roughnessandrandom discrete dopants, considering practical fabrication processes.
Modeling B clustering in Si and SiGe
Authors: Radic Ljubo , Lilak Aaron D. , Law Mark E. 
Published: April 2011

ABSTRACTOur experiments show boron-interstitial cluster dissolution is reduced during oxidation, a behavior not predicted by the current models. Both our experiments and others on the time dependence indicate the reactivation is coming from more than one cluster. Since oxidation induced interstitial injection reduces reactivation, one of the significant clusters has to release an interstitial release during dissolution. Recent ab-initio calculations provide a qualitatively different B clustering model, with two significant cluster species. Based on these energetics, we have developed a new physically based model that for the first time accounts for the experimentally observed cluster dissolution time and ambient dependence.Anomalous B diffusion behavior is also observed in an investigation of Ge influence on B diffusion. Silicon wafers were subjected to a Si preamorphization implant (PAI), followed by Ge and B implants contained within the existing amorphous layer. The control sample received only Si PAI and B implant. Upon annealing, the peak of the B profile shifts towards the surface and increases in magnitude, exhibiting uphill diffusion. The control samples subjected to the same thermal processing exhibit TED, but no uphill diffusion behavior. This is consistent with the model of B diffusion in Si1−xGex, accounting for trapping of B at Ge sites through formation of GeB complex.
Ultra Low-dielectric-constant Materials for 65nm Technology Node and Beyond
Authors: Cui Hao , Moore Darren , Carter Richard , Eda Masaichi , Burke Peter , Gidley David , Peng Huagen 
Published: April 2011

AbstractPore characteristics including pore size distribution, porosity, and pore interconnectivity of PECVD SiCOH inter- layer dielectric (ILD) materials with different dielectric constant (κ) values have been studied. Oxygen plasma damage to SiCOH low-κ films increases dramatically as the κ value decreases. Simulations showed that, compared to the ILD film, the overhead dielectric films have a significant impact on the overall effective κ (κeff) of the BEOL interconnects. Reducing the κ values of these overhead films helps to alleviate the pressure on the κ value requirement of the ILD materials while still meeting the κeff target. Ultra low-κ (ULK) PECVD hydrogenated silicon carbide (H:SiC) films with a κ of 3.0 have been studied for the etch-stop applications. Studies of the chemical composition and bonding structure suggest that less Si-C networκs are formed and more micro-porosity are incorporated in the ULK H:SiC film. The leakage current of the ULK H:SiC film is found to be about 5 times lower than the H:S iC and H:SiCN films with higher κ values. The etch rate of ULK H:SiC film using a standard SiCOH ILD etch chemistry has been found to be negligible. Such an extremely high etch selectivity maκes these films very good etch-stop layers.
Structural and functional characterization of W-Si-N sputtered thin films for copper metallizations
Authors: Vomiero Alberto , Frabboni Stefano , Marchi Enrico Boscolo , Quaranta Alberto , Mea Gianantonio Della , Mariotto Gino , Felisari Laura 
Published: April 2011

AbstractTernary W-Si-N thin films have been reactively sputter-deposited from a W5Si3 target at different nitrogen partial pressures. The composition has been determined by 2.2 MeV4He+ beam, the structure by x-ray diffraction and transmission electron microscope, the chemical bonds by Fourier transform - infrared spectroscopy and the surface morphology by scanning electron microscopy. Electrical resistivity was measured by four point probe technique on the as grown films. The film as-deposited is amorphous with the Si/W ratio increasing from about 0.1 up to 0.55 with the nitrogen content going from 0 to 60 at%. The heat treatments up to 980 °C induce a loss of nitrogen in the nitrogen rich samples. Segregation of metallic tungsten occurs in the sample with low nitrogen content (W58Si21N21). Samples with high nitrogen content preserve the amorphous structure, despite of the precipitation of a more ordered phase inferred by FT-IR absorbance spectrum of the layer treated at highest temperature. The surface morphology depends upon the nitrogen content; the loss of nitrogen induces the formation of blistering and in the most nitrogen rich sample the formation of holes. Electrical resistivity preliminary results on the as grown layers range between 500 and 4750 μωcm passing from the lowest to the highest N concentration.
Optical Interconnect Components for Wafer Level Heterogeneous Hyper-Integration
Authors: Persans P. D. , Ojha M. , Gutmann R. J. , Lu J.-Q. , Filin A. , Plawsky J. 
Published: April 2011

AbstractOptical waveguides for three-dimensionally stacked chip fabrication technologies, in which optical connection between layers plays a central role, are described. CMOS-compatible approaches to optical via and waveguide fabrication are addressed. Detailed modeling is used for design optimization and also addresses how manufacturing variations from ideal design may affect device performance.
Probing Effects of Etching Plasmas on the Properties of Porous Low-k Dielectrics
Authors: Wang L. , Liu J. , Wang W.D. , Chi D.Z. , Gidley D. W. , Yee A. F. 
Published: April 2011

AbstractThe application of porous low-k interlayer dielectrics is needed for reducing the parasitical capacitance, especially at 65-nm node and beyond. The understanding of process-induced modifications to material properties is crucial for a successful integration of these low-k dielectrics. The dry etching processes of porous low-k materials are important modules in ULSI fabrication. In this study, the interaction between MSQ-based JSR LKD-5109 films (shown by PALS to have interconnected 2.8 nm size pores) with CF4/O2 plasma has been investigated. Various ratios of O2 content were designed to characterize its effects on the etch rate, formation of polymerization layer, and properties of the LKD-5109 film. Composition analysis was conducted by SIMS and FTIR. Moisture absorption and fluorine diffusion into low-k films after etch process are observed, along with carbon depletion near the surface region. The influence of etching chemistries on the morphological characteristics of thin Ta barrier layers (8-nm in thickness) deposited on etched low-k films were further investigated by SEM, and it is found that oxygen concentration has significant influences on the morphological characteristics of thin Ta barriers.
Hot Wire Chemical Vapor Deposition as a Novel Synthetic Method for Electroactive Organic Thin Films
Authors: Zaharias Gillian A. , Shi Helen H. , Bent Stacey F. 
Published: April 2011

AbstractWe are exploring the use of hot-wire chemical vapor deposition (HW-CVD) as an alternative, solvent-free technique to produce compact polyconjugated films from vaporized monomers. This paper will focus on our attempts to deposit polyaniline, a polymer with a wide variety of optoelectronic applications. Infrared and X-ray photoelectron spectra have been obtained to characterize HW-CVD films produced using aniline as a precursor. The aromatic ring structure, essential for the polyconjugated network that leads to semiconducting properties, is largely preserved in our method. The bonding structure is analyzed, and the films are found to have significant metal incorporated from the hot wire. The implications of these results for understanding the polymerization and growth mechanism are discussed.
Flexible magnetics on plastic substrates: magnetic lithography, magnetic nanostructures and other applications
Authors: Bandić Z. Z. , Albrecht T.R. , Bonhote C. , Katine J. , Rooks M. 
Published: April 2011

AbstractFlexible Magneticsencompases the design, fabrication and characterization of magnetic devices and systems built on thin flexible substrates. Although device and system functionality is magnetic in nature, flexible magnetics draws interesting parallels to flexible electronics, especially in the challenge of fabrication on plastic substrates. Some of those challenges include substrate surface quality and maximum processing temperature, tooling issues related to mechanical properties of flexible substrates, adhesion of thin films deposited on plastics, as well as thermal stability of fabricated devices.One application of flexible magnetics relevant to the information storage industry is magnetic lithography. Magnetic lithography is a process qualitatively analogous to contact optical lithography. Magnetic lithography transfers information from a patterned magnetic mask (analogous to the optical photomask) to magnetic media (analog of the photoresist), and is interesting for applications in rapid, parallel magnetic recording. The magnetic mask consists of patterned magnetically soft material (FeNiCo, FeCo) on a thin flexible plastic substrate, typically Polyethylene Teraphtalate (PET) or polyimide. When uniformly magnetized media is brought into intimate contact with the magnetic mask, an externally applied magnetic field selectively changes the magnetic orientation in the areas not covered with the soft magnetic material. The flexible magnetic mask offers superior compliance to contaminated or nonplanar magnetic media. We discuss nanofabrication challenges of magnetic masks on plastic substrates, including electron beam lithography, electroplating and lift-off processing on the nanometer scale, adhesion of metal thin films on PET and polyimide substrate, and release of plastic films from the rigid substrates used during the processing. We present results on fabricated magnetic masks, and magnetic force microscopy images of the magnetic transition patterns.Besides fabrication of magnetic nanostructures and devices on plastic substrates, we also present our results on nanoscale patterning of plastic thin film. We will present our results on fabrication of sub-100 nm scale nanochannels in polyimide films, as well as self-assembly of ordered arrays of polyimide nanodots. Nanoscale patterned plastic films are interesting for the potential application in magnetic lithography, as well as for the application in micro- and nanofluidics, due to the mechanical flexibility and biological inertness of plastic materials. We will discuss interesting biosensing systems that may result from the combination of magnetic functionality, electronic control and patterned nanofludic channels on plastic substrates.
Enhancement of the Electrical Properties of ITO Deposited on Polymeric Substrates by Using a ZnO Buffer Layer
Authors: Fortunato E. , Gonçalves A. , Carvalho C. Nunes de , Pimentel A. , Lavareda G. , Marques A. , Martins R. 
Published: April 2011

AbstractIn this paper we present the effect of the insertion of a non-doped nanocrystalline zinc oxide/buffer layer on the electrical, optical and structural properties of indium tin oxide produced at room temperature by radio frequency plasma enhanced reactive thermal evaporation on polymeric substrates. The electrical resistivity of the ITO films is reduced by more than two orders of magnitude (4.5×10−1 to 2.9×10−3 ωcm). From the Hall effect measurements it is observed that the large decrease associated to the electrical resistivity, is due to the increase associated to the Hall mobility. Concerning the optical properties no effect was observed, being the transmittance in the visible and near the infra red region always higher than 80%.
A method for in-situ measurements of the growth in the bulk of deformed single crystals at the 3DXRD microscope
Authors: Schmidt S. , Jensen D. Juul 
Published: April 2011

AbstractWith the Three Dimensional X-ray Diffraction microscope (3DXRD) located at the European Synchrotron Radiation Facility (ESRF) full 3D spatial information of grains in the interior of a sample can be measured non-destructively. In this paper we discuss the possibility of an extension to this scenario, namely in-situ annealing studies, where the 3D spatial grain shape can be monitored as function of time. Consequently, local boundary migration rates can be estimated and compared to the deformed microstructure. Such information may reveal to what extend the deformed microstructure influences the growth of a grain during recrystallization.
The General Synthesis of Nanostructured V/VI Semiconductors
Authors: Christian Paul , O'Brien Paul 
Published: April 2011

ABSTRACTSemiconductors in the V/VI series have band gaps ranging from 2.2 eV for Sb2S3 to 0.21 eV for Bi2Te3 spanning the range seen from conventional mid to narrow band gap materials to semi-metals. These materials, especially those with narrower band gaps, demonstrate thermo-electric properties and are used in Peltier devices. There are examples in the literature of the synthesis of several of these materials in a nanostructured form, however the reactions often rely on highly toxic reagents, especially in the case of tellurium containing materials. Further more there are no reports of general routes applicable to all three chalcogenides.In this paper we describe a general method for the synthesis of chalcogenide V/VI nanomaterials by the reaction of acetate salts with the corresponding chalcogenide under reflux conditions in long chain alkyl amines, typically octylamine or dodecylamine. The effect of temperature and capping agent on the morphology of the final product are discussed and in particular the synthesis of Bi2S3 nanorods, Bi2Se3 and Bi2Te3 nanowafers and Sb2Se3 nanowires are described.
Prospect for III-Nitride Heterojunction MOSFET Structures and Devices
Authors: Johnson M. A. L. , Barlage D. W. , Braddock Dave 
Published: April 2011

ABSTRACTHeterojunction field effect transistors (HFET) for high-frequency and high-power electronics have been an area of active research in recent years as a key enabling technology for applications ranging from wireless communications to power distribution. III-Nitride semiconductors are a leading candidate for fulfilling the material requirements of these devices based on the combination of large bandgap energy, high thermal conductivity, high electron mobility and saturated electron velocity. While III-Nitride HFETs have demonstrated remarkable advances, serious materials related limitations still exist, primarily related to charge states and trapping effects at the semiconductor surface. Several groups have investigated solutions such as the deposition of dielectric passivation layers and asymmetric field-plate gate geometries for controlling the influence of trap states near the metal/semiconductor FET interface. We have demonstrated a metal-oxide semiconductor FET (MOSFET) with a substantially unpinned interface which is capable of establishing substantial charge accumulation under the gate. These III-Nitride MOSFETs may be designed to operate in either depletion mode or enhancement mode. GaN/InGaN heterojunction MOSFETs exhibit enhancement mode peak transconductance at gate voltages Vg>+5V, corresponding to energy greater than the bandgap of the underlying semiconductor which provides strong evidence of an unpinned MOS interface. Additionally III-Nitride MOSFETs eliminate the need for field plate gate structures as the electric field geometry in the gate-drain region changes limiting the tunneling of charge to unfilled surface states. In depletion mode, low-rf dispersion InGaN/GaN MOSFETs exhibit excellent microwave with ft = 8GHz for optically defined gates dimensions.We review the history of compound semiconductor MOSFET development and overlaying these developments with recent advances in the III-Nitride materials and device research. Differences in chemistry of III-Nitrides relative to all other compound semiconductors and the epitaxial deposition of gate-oxides such as Gadolinium Gallium Oxide (GGO), opens the possibility for dramatically improved devices at microwave and mm-wave frequencies as well as power MOSFET rectifiers. Initial III-Nitride MOSFETs results are presented as well as a quaternary thermodynamic framework for the stability of gate-oxide on nitride semiconductors. We also identify key materials related research challenges expected to impact the ongoing development of III-Nitride MOSFETs.