bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of low-k UV Curing: Effect of Wavelength on Critical Properties of the Dielectrics
Authors: Aksenov German , De Roest David , Verdonck Patrick , Marsik Premysl , Shamiryan Denis , Baklanov Mikhail R 
Published: August 2010

AbstractThe results of recent investigations show that after UV curing of CVD SiCOH low-k films deposited with organic material (porogen) some amount of the porogen remains in the cured films in the form of non-volatile graphitized phase, known as “porogen residue”. These residues could influence leakage current and reliability. The goal of the present work is investigation of the different parameters of UV curing that can influence amount of the porogen residue. In this work we focused generally on the study of the amount of porogen residues as function of the wavelength of curing light and the porosity of the material (amount of deposited porogen). To study the curing dependence on the wavelength, we compared optical properties (measured by spectroscopic ellipsometry) and IR adsorption (measured by FTIR) of samples cured by 172 nm monochromatic light (lamp A) with samples cured by broadband source with wavelength more than 200 nm (lamp B). To understand how the amount of porogen residue depends on the amount of deposited porogen (porosity), three films with different k-value were deposited: a film with k = 3 deposited without porogen and two porogen-based low-k with target k-value of 2.5 and 2.3. Furthermore, taking into account that He/H2 plasma effectively removes the porogen residues from porous films without any plasma damage of the matrix material, we exposed the films to that plasma. Then these films were cured by broadband lamp at different temperatures and amount of porogen residues was measured by ellipsometry. It was found that He/H2 plasma cannot fully remove the porogen and causes film shrinkage. The Subsequent UV curing does not produce significant changes.
Large-Scale Electromigration Statistics for Cu Interconnects
Authors: Hauschildt Meike , Gall Martin , Hernandez Richard 
Published: August 2010

AbstractEven after the successful introduction of Cu-based metallization, the electromigration failure risk has remained one of the important reliability concerns for advanced process technologies. The observation of strong bimodality for the electron up-flow direction in dual-inlaid Cu interconnects has added complexity, but is now widely accepted. More recently, bimodality has been reported also in down-flow electromigration, leading to very short lifetimes due to small, slit-shaped voids under vias. For a more thorough investigation of these early failure phenomena, specific test structures were designed based on the Wheatstone Bridge technique. The use of these structures enabled an increase of the tested sample size past 1.1 million, allowing a direct analysis of electromigration failure mechanisms at the single-digit ppm regime. Results indicate that down-flow electromigration exhibits bimodality at very small percentage levels, not readily identifiable with standard testing methods. The activation energy for the down-flow early failure mechanism was determined to be 0.83 ± 0.01 eV. Within the small error bounds of this large-scale statistical experiment, this value is deemed to be significantly lower than the usually reported activation energy of 0.90 eV for electromigration-induced diffusion along Cu/SiCN interfaces. Due to the advantages of the Wheatstone Bridge technique, we were also able to expand the experimental temperature range down to 150 °C, coming quite close to typical operating conditions up to 125 °C. As a result of the lowered activation energy, we conclude that the down-flow early failure mode may control the chip lifetime at operating conditions. The slit-like character of the early failure void morphology also raises concerns about the validity of the Blech-effect for this mechanism. A very small amount of Cu depletion may cause failure even before a stress gradient is established. We therefore conducted large-scale statistical experiments close to the critical current density-length product (jL)*. The results indicate that even at very small failure percentages, this critical product seems to extrapolate to about 2900 ± 400 A/cm for SiCOH-based dielectrics, close to previously determined (jL)* products of about 3000 ± 500 A/cm for the same technology node and dielectric material, acquired with single link interconnects. More detailed studies are currently ongoing to verify the extrapolation methods at small percentages. Furthermore, the scaling behavior of the early failure population was investigated.
Combinatorial Approaches to Investigations of Thermochromic Materials
Authors: Tang Hong , White Mary Anne 
Published: August 2010

AbstractThermochromic materials change color with temperature. Organic ternary mixtures composed of a dye, developer and solvent can reversibly change color with temperature. Although they are used in many commercial products, little is known about the detailed mechanism of thermochromism. Given the wide range of available components and compositions that could potentially show thermochromic behavior, we have embarked on combinatorial studies using inkjet printing to directly prepare thermochromic mixtures on paper.
Fabrication and Electrical Characterization of Metal-Silicide Nanocrystals for Nano Floating Gate Nonvolatile Memory
Authors: Han Seung Jong , Seo Ki Bong , Lee Dong Uk , Kim Eun Kyu , Oh Se-Mam , Cho Won-Ju 
Published: August 2010

AbstractWe have fabricated the nano-floating gate memory with the TiSi2 and WSi2 nanocrystals embedded in the dielectrics. The TiSi2 and WSi2 nanocrystals were created by using sputtering and rapidly thermal annealing system, and then their morphologies were investigated by transmission electron microscopy. These nanocrystals have a spherical shape with an average diameter of 2-5 nm. The electrical properties of the nano-floating gate memory with TiSi2 and WSi2 nanocrystals were characterized by capacitance-voltage (C-V) hysteresis curve, memory speed and retention. The flat-band voltage shifts of the TiSi2 and WSi2 nanocrystals capacitors obtained appeared up to 4.23 V and 4.37 V, respectively. Their flat-band voltage shifts were maintained up to 1.6 V and 1 V after 1 hr.
HfO2-based Thin Films Deposited by RF Magnetron Sputtering
Authors: Khomenkova Larysa , Dufour Christian , Coulon Pierre-Eugène , Bonafos Caroline , Gourbilleau Fabrice 
Published: August 2010

AbstractHfO2-based layers prepared by RF magnetron sputtering were studied by X-ray diffraction, infrared absorption spectroscopy and transmission electron microscopy techniques. The effect of the deposition parameters and post-deposition annealing treatment on the properties of the layers was investigated. The amorphous-crystalline transformation of pure HfO2 layers is observed to be stimulated by annealing treatment at 800 ° C. It was found that the incorporation of silicon in HfO2 matrix allows to prevent crystallization of the layers and to shift the crystallization temperature to values up to 900 °C.
Key Technologies for FeRAM Backend Module
Authors: Ren Tian-Ling , Zhang Ming-Ming , Jia Ze , Wang Lin-Kai , Wei Chao-Gang , Xue Kan-Hao , Zhang Ying-Jie , Hu Hong , Xie Dan , Liu Li-Tian 
Published: August 2010

AbstractFerroelectric random access memory (FeRAM) is believed to be the most promising candidate for the next generation non-volatile memory due to its fast access time and low power consumption. Fabrication technologies of FeRAM can be divided into two parts: CMOS technologies for circuits which are standard and can be shared with traditional IC process line, and process relating to ferroelectric which is separated with CMOS process and defined as backend module. This paper described technologies for integrating ferroelectric capacitors into standard CMOS, mainly about modeling of ferroelectric capacitors and backend fabrication technologies. Hysteresis loop of the ferroelectric capacitor is the basis for FeRAM to store data. Models to describe this characteristic are the key for the design of FeRAM. A transient behavioral ferroelectric capacitor model based on C-V relation for circuit simulation is developed. The arc tangent function is used to describe the hysteresis loop. “Negative capacitance” phenomenon at reversing points of applied voltage is analyzed and introduced to the model to describe transient behaviors of the capacitor. Compact equivalent circuits are introduced to integrate this model into HSPICE for circuit simulation. Ferroelectric materials fabrication, electrodes integration and etching are the main technologies of FeRAM fabrication process. An metal organic chemical vapor deposition (MOCVD) process is developed to fabricate high quality Pb(Zr1-xTix)O3 (PZT) films. Pt is known to cause the fatigue problems when used as electrodes with PZT. Ir is used as electrodes to improve the fatigue property of PZT based capacitors, and mechanism of the fatigue is analyzed. Hard mask is used to reduce the size of the capacitors and damage caused in etching process. In our process, Al2O3 is developed as hard mask, which simplifies the FeRAM backend integration process.
Electrically-controlled Resistance Switching Accompanied by Ultra-high-J Domains of VO2 Films
Authors: Sakai Joe 
Published: August 2010

AbstractThe electric-field-induced resistance switching (EIRS) phenomenon on a VO2 planar-type junction fabricated on a Al2O3 (0001) substrate was studied by performing current-voltage (I-V) measurement and optical microscope observation simultaneously. It was confirmed that current density J of the low-resistance-state (LRS) region is maintained constant at approximately 1.6 × 106 A/cm2, while the volume of the LRS region was changed according to the current. A survey of the previous I-V traces on EIRS of VO2 revealed that almost all the junctions so far had shown non-zero V-intercepts, which are attributed to the volume change of the LRS regions. The maintenance of high-J in the LRS region is considered to be related to the electrically-induced metallic phase mechanism reported in perovskite-type manganites.
Conformal MOCVD Deposition of GeSbTe in High Aspect Ratio Via Structure for Phase Change Memory Applications
Authors: Zheng Jun-Fei , Chen Phil , Hunks William , Stender Matthias , Xu Chongying , Li Weimin , Roeder Jeff , Kamepalli Smuruthi , Schell Carl , Reed James , Ricker Jim , Sandoval Regino , Fournier Jeffery , Czubatyj Wally , Wicker Guy , Dennison Chuck , Hudgens Stephen , Lowrey Tyler 
Published: August 2010

AbstractWe have demonstrated conformal deposition of amorphous GeSbTe films in high aspect ratio structures by MOCVD. SEM analysis showed the as-deposited GeSbTe films had smooth morphologies and were well controlled for void free amorphous conformal deposition. GeSbTe films adhere well to SiO2, TiN, and TiAlN. The morphology and adhesion are stable in 420°C post process. By annealing at 365°C, amorphous GeSbTe films converted into crystalline GeSbTe with polycrystalline grain sizes of 5nm. Film resistivity in the crystalline phase ranged from 0.001 to 0.1 Ω-cm, suitable for device applications. Phase change devices fabricated with confined via structures filled with MOCVD GeSbTe showed cycle endurances up to 1×1010with a dynamic set/rest resistance of two orders of magnitude.
Emerging Technologies and Opportunities Based on the Magneto-Electric Effect in Multiferroic Composites
Authors: Vopsaroiu Marian , Blackburn John , Cain Markys G. 
Published: August 2010

AbstractMultiferroic materials are recognized today as one of the new emerging technologies with huge potential for both academic research and commercial developments. Multiferroic composites are in particular more attractive for studies due to their enhanced properties, especially at room temperature, in comparison to the single-phase multiferroics. In this paper, we examine some of the theoretical aspects regarding one type of multiferroic composites (laminated structures) and we discuss one of the many possible applications of these exciting structures. We highlight the main advantages composite systems have over single-phase multiferroics and the similarities that exist between them.
Room Temperature Ferromagnetism and Lack of Ferroelectricity in Thin Films of ‘Biferroic’ YbCrO3
Authors: Nagar Sandeep , Rao K. V. , Belova Lyubov M. , Catalan G. , Hong J. , Scott James , Tyagi A. K. , Jayakumar O. D. , Shukla R. , Sheng Yi , Guo Jinghua 
Published: August 2010

AbstractSearch for novel multi-functional materials, especially multiferroics, which are ferromagnetic above room temperature and at the same time exhibit a ferroelectric behavior much above room temperature, is an active topic of extensive studies today. Ability to address an entity with an external field, laser beam, and also electric potential is a welcome challenge to develop multifunctional devices enabled by nanoscience. While most of the studies to date have been on various forms of Bi- and Ba based Ferrites, rare earth chromites are a new class of materials which appear to show some promise. However in the powder and bulk form these materials are at best canted antiferromagnetics with the magnetic transition temperatures much below room temperature. In this presentation we show that thin films of YbCrO3 deposited by Pulsed Laser Deposition exhibit robust ferromagnetic properties above room temperature. It is indeed a welcome surprise and a challenge to understand the evolution of above room temperature ferromagnetism in such a thin film. The thin films are amorphous in contrast to the powder and bulk forms which are crystalline. The magnetic properties are those of a soft magnet with low coercivity. We present extensive investigations of the magnetic and ferroelectric properties, and spectroscopic studies using XAS techniques to understand the electronic states of the constituent atoms in this novel Chromite. While the amorphous films are ferromagnetic much above room temperature, we show that any observation of ferroelectric property in these films is an artifact of a leaky highly resistive material.
Competing Magnetic Interactions in Magnetoelectric YbMnO3
Authors: Ray Shishir , Zou Ying , Williamsen Mark S. , Sen Somaditya , Buroker Larry , Guptasarma Prasenjit 
Published: August 2010

AbstractWe clarify here certain aspects of the magnetic field (H) – temperature (T) phase diagram of YbMnO3, a hexagonal Rare-Earth manganite oxide in which two multiferroic ordered states – ferroelectricity and antiferromagnetism coexist at low temperature. Single crystals of YbMnO3 were carefully grown from a Floating Zone (FZ) at low speed, then oriented and studied at variable temperature and magnetic field. Magnetization and heat capacity measurement show features corresponding to the antiferromagnetic (AFM) ordering of Mn3+, and the rare earth Yb3+. We find that the ordering temperature of Mn3+ is independent of applied magnetic field up to 5T. However, contrary to previous reports in flux-grown crystals, we do not observe a complete suppression of Yb3+ order above 0.1T. Instead, we find that Yb3+ remains at least up to 1 T, suggesting a revision of our current understanding of the ordering mechanism of the Mn-Yb and Yb –Yb sub-lattices in this hexagonal structure.
Electrodeposited Cu-In-Ga-Se Thin Films for CIGS-based Solar Cells
Authors: Bhattacharya Raghu 
Published: August 2010

AbstractCyclic voltammogram studies were performed on H2SeO3, CuSO4, In2(SO4)3, GaCl3, H2SeO3 + CuSO4 + In2(SO4)3 and H2SeO3 + CuSO4 + In2(SO4)3 + GaCl3 to understand the electrodeposition mechanism. The reduction potential from the cyclic voltammogram studies indicates that the first deposited layer is Cu from the Cu-In-Se and Cu-In-Ga-Se solution mixture. The subsequent deposition of the In and Ga layer is more favorable on the first-deposited Cu layer.
Electronic structure and phase stability of In-free photovoltaic semiconductors, Cu2ZnSnSe4 and Cu2ZnSnS4 by first-principles calculation
Authors: Maeda Tsuyoshi , Nakamura Satoshi , Wada Takahiro 
Published: August 2010

AbstractWe have theoretically evaluated the phase stability and electronic structure of Cu2ZnSnSe4 (CZTSe) and Cu2ZnSnS4 (CZTS). The enthalpies of formation for kesterite, stannite and wurtz-stannite phases of CZTSe and CZTS were calculated using a plane-wave pseudopotential method within the density functional formalism. For CZTSe, the calculated formation enthalpy (ΔH) of the kesterite phase (−312.7 kJ/mol) is a little smaller than that of the stannite phase (−311.3 kJ/mol) and much smaller than that of the wurtz-stannite phase (−305.7 kJ/mol). For CZTS, the ΔH of the kesterite phase (−361.9 kJ/mol) is smaller than that of the stannite phase (−359.9 kJ/mol) and much smaller than that of the wurtz-stannite phase (−354.6 kJ/mol). The difference of ΔH between the kesterite and stannite phases for CZTS is greater than that for CZTSe. This indicates the kesterite phase is more stable than the stannite phase in CZTS compared with CZTSe. The valence band maximums (VBMs) of both the kesterite- and stannite-type CZTSe(CZTS) are antibonding orbitals of Cu 3d and Se 4p (S 3p). The conduction band minimums (CBMs) are antibonding orbitals of Sn 5s and Se 4p (S 3p). The Zn atom does not affect the VBM or the CBM in either CZTSe(CZTS). The theoretical band gap of the kesterite phase calculated with sX-LDA in both CZTSe and CZTS is a little wider than that of the wurtz-stannite phase and much wider than that of the stannite phase.
Development of ZnTe Contacts for Cd1-xMgxTe Thin-Film Solar Cells for Tandem Applications
Authors: Duenow Joel N. , Dhere Ramesh , Li Jian , Metzger Wyatt K. , Duda Anna , Gessert Tim A. 
Published: August 2010

AbstractPolycrystalline Cd1-xMgxTe (CMT) thin films are a potential absorber material for two-junction thin-film tandem solar cell applications because the desired top cell bandgap range of 1.6 to 1.8 eV is readily obtained using CMT with only small resultant changes in the lattice constant from that of CdTe. Tandem devices require the top cell to have a transparent back contact to transmit the sub-bandgap spectrum to the bottom cell. Sputtered Cu-doped ZnTe (ZnTe:Cu) thin films, which offer potential as a transparent back contact interface layer, have been used successfully in CdTe devices. We apply ZnTe:Cu back contacts to CMT devices to continue development toward a transparent top cell. We describe the effects of depositing ZnTe:Cu at different temperatures and with different Cu contents on the net acceptor concentration, minority carrier lifetime, and device performance. We present here the highest reported CMT device efficiency of 9.6% at a bandgap of 1.57 eV.
Enhancement of InGaN-based MQW Grown on Si(111) Substrate by Underlying AlGaN/GaN SLS Cladding Layer
Authors: Ahmad Shuhaimi Bin Abu Bakar , Suzue Takaaki , Nomura Yukiyasu , Maki Yoshinori , Egawa Takashi 
Published: August 2010

AbstractThis paper reports enhanced internal-quantum-efficiency (IQE) in InGaN-based multi-quantum-well (MQW) grown on Si(111) substrate with underlying strained-layer-superlattice (SLS) cladding layer for application in LDs and LEDs. In comparative study between a thick Al0.03Ga0.97N bulk and an Al0.06Ga0.94N/GaN SLS cladding layer, transmission-electron-microscopy (TEM) images reveal that Al0.06Ga0.94N/GaN SLS cladding layer is effective to suppress threading dislocations. A higher IQE has been achieved in sample with underlying Al0.06Ga0.94N/GaN SLS cladding layer, compared to that of Al0.03Ga0.97N bulk cladding layer. IQE of 31.6% has been achieved in sample with underlying Al0.06Ga0.94N/GaN SLS cladding layer when the MQW thickness is reduced to 2 nm.
ZnO Thin Film Deposition on Sapphire Substrates by Chemical Vapor Deposition
Authors: Chen Zhuo , Salagaj Tom , Jensen Christopher , Strobl Karlheinz , Nakarmi Mim , Shum Kai 
Published: August 2010

AbstractZnO thin films with thickness around 200 nm were deposited on a-plane sapphire substrates by Chemical Vapor Deposition (CVD) method with a mixed ZnO-powder/C-powder solid source. These films were characterized by Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), and photoluminescence (PL) spectroscopy. The correlation between surface structural properties of ZnO thin films and their optical signature measured by temperature dependence of PL is investigated for various growth conditions such as flow rate O2 injection gas and growth temperature. At room temperature, the columbic interaction enhanced absorption edge of 3.305 eV of these films was determined by optical absorption measurements.
Photooxidation of Water Using Vertically Aligned Nanotube Arrays: A comparative study of TiO2, Fe2O3and TaON nanotubes
Authors: Misra Mano , Banerjee Subarna , Mohapatra Susanta K , John Shiny E , Howard Cameron 
Published: August 2010

AbstractThere is a real need for a material which absorbs in the visible light of the solar spectrum, is stable in water and at the same time economical. One-dimensional vertically aligned nanotubes have contributed to a great extent towards the visible light driven photoelectrolysis of water. In this work, we give an overview of the different nanotubes obtained through anodization of various metals and their application in the photooxidation of water
Synthesis and Electrorheological Activity of Nanosized Particles of Hybrid Material Silica / Cetylpyridinium Chloride
Authors: Korobko Evguenia , Kouznetsova Tatyana , Novikova Zoya , Bedik Natalia , Zhurauski Mikalai 
Published: August 2010

AbstractHybrid organic-inorganic nanocomposite silica with surfactant � cetylpyridinium chloride with the polyphase structure, having a high electrorheological activity, is synthesized using sol-gel method. Physical-mechanical characteristics of dispersions based on mineral oil and synthesized powder with the concentration of 20 and 30 % by weight are investigated. The results of the shear stress measurements versus the strength of the dc and ac (frequency 50 Hz) electric fields (0 � 3.5 kV/mm) at Couette shear (shear rate 8 � 390 s) and yield stress in the range of temperatures 20 � 97 �C are presented. The comparative analysis of the results obtained with the results for the powder of the hybrid organic-inorganic nanocomposite silica/ polyethylene glycol is carried out.
Biological Applications of Programmable Optoelectrofluidic Manipulation
Authors: Park Je-Kyun 
Published: August 2010

AbstractThis paper presents a new programmable particle manipulation using a lab-on-a-display platform, which is a kind of optoelectrofluidic platform applying a liquid crystal display (LCD) as a display device for generating virtual electrodes in optoelectronic tweezers. The reconfigurable virtual electrodes in the lab-on-a-display are more advantageous than other devices which apply the micro-patterned electrodes, because we can freely control the size and position of electrodes as well as the voltage conditions, which affect the particle movements such as concentration and separation of particles. Due to its simple structures, cheap manufacturing costs, and high performances, this new LCD-based optoelectrofluidic platform can be applied to the interactive manipulation of polystyrene microspheres and blood cells. In addition, a method to discriminate normal oocytes for in vitro fertilization is demonstrated by combining the gravity effect with the optically induced positive dielectrophoresis (DEP). The discrimination performance can be enhanced due to the reduction of friction forces acting on the oocytes which are relatively large and heavy cells being affected by the gravity field. With the same device, we also demonstrate the size-dependent microparticle separation as well as the local concentration and assembly of microparticles originated from the image-driven AC electrokinetics such as DEP and AC electroosmosis. The particle movements result from the frequency-dependent behavior according to the particle diameter. This novel technique can be applied to rapidly concentrate, separate and pattern micro-/nanoparticles and biomolecules in many biological and chemical applications.