Analysis of Temperature Effect in Quadruple Gate Nano-scale FinFET

Silicon - Quadruple gate FinFET is a promising candidate among other multi-gate MOS devices due to it’s better scalability and higher short channel effect suppression capability in advanced...     

Preface of special issue of CCSN2016

Microsystem Technologies -     

Mixed oxide supported hydrodesulfurization catalysts—a review

Support effects form important aspect of hydrodesulfurization (HDS) studies and mixed oxide supports received maximum attention in the last two decades. This review will focus attention on studies on mixed oxide supported Mo and W catalysts. For convenience of discussion, these are divided into Al₂O₃ containing mixed oxide supports, TiO₂ containing mixed oxide supports, ZrO₂ containing mixed oxide supports and other mixed oxide supports containing all the rest. TiO₂ containing mixed oxides received maximum attention, especially TiO₂–Al₂O₃ supported catalysts. A brief discussion about their prospects for application to ultradeep desulfurization is also included. An overview of the available literature with emphasis on research carried out in our laboratory form the contents of this publication.     

Acoustic study of nano-crystal embedded PbO-P2O5 glass

Nano-crystal embedded PbO-P₂O₅ glass has been prepared and characterized by XRD and TEM measurements. The ultrasonic velocity and attenuation measured within the temperature range 80–300 K show significant structure and interesting feature with the presence of nano-crystalline region. The glass samples were prepared by melt-quench method and nano-crystals of different sizes were produced by heat treatment of the glasses for different durations of heating. All the processes were carried out at or above glass transition temperature. A theoretical model that takes account of the effects of thermally activated relaxation, anharmonicity as well as microscopic elastic inhomogeneities arising out of fluctuations has been successfully applied to interpret the variation of ultrasonic velocity and attenuation data. An interesting outcome of this application has been to propose a method for the determination of the size of nano-crystals from the ultrasonic attenuation data.     

Conducting composites of poly(N‐vinylcarbazole), polypyrrole,and polyaniline with 13X‐zeolite

N‐vinylcarbazole (NVC) was polymerized by 13X zeolite alone in melt (65°C) or in toluene (110°C) and a poly(N‐vinylcarbazole) (PNVC)‐13X composite was isolated. Composites of polypyrrole (PPY) and polyaniline(PANI) with 13X zeolite were prepared via polymerization of the respective monomers in the presence of dispersion of 13X zeolite in water (CuCl₂ oxidant) and in CHCl₃ (FeCl₃ oxidant) at an ambient temperature. The composites were characterized by Fourier transform infrared analyses. Scanning electron microscopic analyses of various composites indicated the formation of lumpy aggregates of irregular sizes distinct from the morphology of unmodified 13X zeolite. X‐ray diffraction analysis revealed some typical differences between the various composites, depending upon the nature of the polymer incorporated. Thermogravimetric analyses revealed the stability order as: 13X‐zeolite > polymer‐13X‐zeolite > polymer. PNVC‐13X composite was essentially a nonconductor, while PPY‐13X and PANI‐13X composites showed direct current conductivity in the order of 10^?4 S/cm in either system. However, the conductivity of PNVC‐ 13X composite could be improved to 10^?5 and 10^?6 S/cm by loading PPY and PANI, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 913–921, 2006     

Analysis of spring softening effect on the collapse voltage of capacitive MEMS ultrasonic transducers

Microsystem Technologies - This paper explained the dependency of collapse voltage on semiconductor device structural features (membrane diameter, membrane thickness and the vertical distance...     

The role of pressure on thin amorphous carbon films deposited using microwave surface wave plasma CVD

We report the effects of gas composition pressure (GCP) on the optical, structural and electrical properties of thin amorphous carbon (a-C) films grown on p-type silicon and quartz substrates by microwave surface wave plasma chemical vapor deposition (MW SWP CVD). The films, deposited at various GCPs ranging from 50 to 110 Pa, were studied by UV/VIS/NIR spectroscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and current–voltage characteristics. The optical band gap of the a-C film was tailored to a relatively high range, 2.3–2.6 eV by manipulating GCPs from 50 to 110 Pa. Also, spin density strongly depended on the band gap of the a-C films. Raman spectra showed qualitative structured changes due to sp³/sp² carbon bonding network. The surfaces of the films are found to be very smooth and uniform (RMS roughness < 0.5 nm). The photovoltaic measurements under light illumination (AM 1.5, 100 mW/cm²) show that short-circuit current density, open-circuit voltage, fill factor and photo-conversion efficiency of the film deposited at 50 Pa were 6.4 μA/cm², 126 mV, 0.164 and 1.4 × 10^− 4% respectively.     

Synthesis of nitrogen incorporated diamond-like carbon thin films using microwave surface-wave plasma CVD

Nitrogenated diamond-like (DLC:N) carbon thin films have been deposited by microwave surface wave plasma chemical vapor deposition on silicon and quartz substrates, using argon gas, camphor dissolved in ethyl alcohol composition and nitrogen as plasma source. The deposited DLC:N films were characterized for their chemical, optical, structural and electrical properties through X-ray photoelectron spectroscopy, UV/VIS/NIR spectroscopy, Raman spectroscopy, atomic force microscope and current–voltage characteristics. Optical band gap decreased (2.7 to 2.4 eV) with increasing Ar gas flow rate. The photovoltaic measurements of DLC:N / p-Si structure show that the open-circuit voltage (V_oc) of 168.8 mV and a short-circuit current density (J_sc) of 8.4 μA/cm² under light illumination (AM 1.5 100 mW/cm²). The energy conversion efficiency and fill factor were found to be 3.4 × 10^{− 4}% and 0.238 respectively.     

Influence of untreated and novel electron‐beam‐modified surface‐coated silica filler on the thermorheological properties of ethylene–octene copolymer

We developed surface‐modified silica fillers by coating these with an acrylate monomer, trimethylolpropane triacrylate, or a silane coupling agent, triethoxyvinyl silane, followed by electron‐beam irradiation at room temperature. These were incorporated in an ethylene–octene copolymer rubber. Thermorheological studies of the unvulcanized ethylene–octene copolymer and its untreated and modified silica‐filled composites were done with a shear dynamic oscillating rheometer. Modification of the silica filler, especially via the silanization process followed by electron beam treatment, significantly reduced filler–filler networking as revealed from the log–log plots of storage modulus and complex shear viscosity, and its real component. The rheological complexity of the compositions was analyzed from a double logarithmic plot of the storage modulus and loss modulus. The results obtained from the master curves constructed on the basis of the time–temperature superposition principle and the activation energy calculated from the Arrhenius equation for the flow of above these compounds further supported these findings. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2453–2459, 2003     

Maya crude hydrodemetallization and hydrodesulfurization catalysts: An effect of TiO2 incorporation in Al2O3

Hydrotreating of Maya heavy crude oil over high specific surface area CoMo/TiO₂–Al₂O₃ oxide supported catalysts was studied in an integral reactor close to industrial practice. Activity studies were carried out with Maya crude hydrodesulfurization (HDS), hydrodemetallization (HDM), hydrodenitrogenation (HDN), and hydrodeasphaltenization (HDAs) reactions. The effect of support composition, the method of TiO₂ incorporation, and the catalyst deactivation are examined. Supported catalysts are characterized by BET specific surface area (SSA), pore volume (PV), pore size distribution (PSD), and atomic absorption. It has been found that sulfided catalysts showed a wide range of activity variation with TiO₂ incorporation into the alumina, which confirmed that molybdenum sulfided active phases strongly depend on the nature of support. The pore diameter and nature of the active site for HDS, HDM, HDN, and HDAs account for the influence of the large reactant molecules restricted diffusion into the pore, and/or the decrease in the number of active sites due to the MoS₂ phases buried with time-on-stream. The textural properties and hysteresis loop area of supported and spent catalysts indicated that catalysts were deactivated at the pore mouth due to the metal and carbon depositions. The atomic absorption results agreed well regarding the textural properties of spent catalysts. Thus, incorporation of TiO₂ with γ-Al₂O₃ alters the nature of active metal interaction with support, which may facilitate the dispersion of active phases on the support surface. Therefore, the TiO₂ counterpart plays a promoting role to HDS activity due to the favorable morphology of MoS₂ phases and metal support interaction.