A CMOS multichannel 10-Gb/s transceiver

We describe a CMOS multichannel transceiver that transmits and receives 10 Gb/s per channel over balanced copper media. The transceiver consists of two identical 10-Gb/s modules. Each module operates off a single 1.2-V supply and has a single 5-GHz phase-locked loop to supply a reference clock to two transmitter (Tx) channels and two receiver (Rx) channels. To track the input-signal phase, the Rx channel has a clock recovery unit (CRU), which uses a phase-interpolator-based timing generator and digital loop filter. The CRU can adjust the recovered clock phase with a resolution of 1.56 ps. Two sets of two-channel transceiver units were fabricated in 0.11-/spl mu/m CMOS on a single test chip. The transceiver unit size was 1.6 mm /spl times/ 2.6 mm. The Rx sensitivity was 120-mVp-p differential with a 70-ps phase margin for a common-mode voltage ranging from 0.6 to 1.0 V. The evaluated jitter tolerance curve met the OC-192 specification.     

High resistivity measurement of SiC wafers using different techniques

To establish fast, nondestructive, and inexpensive methods for resistivity measurements of SiC wafers, different resistivity-measurement techniques were tested for characterization of semi-insulating SiC wafers, namely, the four-point probe method with removable graphite contacts, the van der Pauw method with annealed metal and diffused contacts, the current-voltage (I-V) technique, and the contactless resistivity-measurement method. Comparison of different techniques is presented. The resistivity values of the semi-insulating SiC wafer measured using different techniques agree fairly well. As a result, application of removable graphite contacts is proposed for fast and nondestructive resistivity measurement of SiC wafers using the four-point probe method. High-temperature van der Pauw and room-temperature Hall characterization for the tested semi-insulating SiC wafer was also obtained and reported in this work.     

Metastable phase relation and phase equilibria in the Cr2O3-Fe2O3 system

In order to ascertain the metastable phase relation in the Cr₂O₃-Fe₂O₃ system, the existing phases were investigated by X-ray analysis using samples obtained by heating the coprecipitated powders for 1 h at 600–1000°C. There was a metastable two-phase region of Cr₂O₃-rich (CC) and Fe₂O₃-rich (FC) phases below about 940°C. Equilibrium state of 1:1 composition at 600–900°C was considered to be a single phase of the corundum solid solution. The metastable two-phase CC + FC region was suggested to appear probably due to the compositional inhomogeneity in the coprecipitated powders.     

Experimental characterisation of the drying effect on uniaxial mechanical behaviour of mortar

The main objective of this present study was to evaluate, for a standard mortar, the drying effect on its mechanical behaviour. Numerous uniaxial compression tests were thus performed with loading-unloading cycles. They were carried out on different samples previously preserved under various conditions of conservation: preserved from desiccation, air drying and rapid drying at 60°C. The obtained results showed significant influences of these conditions on the material behaviour (increase in strength, decrease in Young's modulus and Poisson's ratio) and the necessity of taking into account the coupling effects between mechanical—poromechanical behaviours and drying.     

Gamma-irradiation-induced Ag/SiO2 composite films and their optical absorption properties

Small Ag particles or clusters dispersed mesoporous SiO₂ composite films were prepared by a new method: First the matrix SiO₂ films were prepared by sol-gel process combined with the dip-coating technique, then they were soaked in AgNO₃ solutions followed by irradiation of γ-ray at room temperature and in ambient pressure. The structures of these films were examined by X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), and optical absorption spectroscopy. It has been shown that the Ag particles grown within the porous SiO₂ films are very small, and they are isolated and dispersed from each other with very narrow size distributions. With increasing the soaking concentration and an additional annealing, an opposite peakshift effect of the surface plasmon resonance (SPR) was observed in the optical absorption measurements.     

Analysis of the mechanism of die soldering in aluminum die casting

A mechanism of soldering of an aluminum alloy die casting to a steel die is proposed. A soldering critical temperature is postulated, at which iron begins to react with aluminum to form an aluminum-rich liquid phase and solid intermetallic compounds. The liquid joins the die with the casting upon solidification. The critical temperature is determined by the elements in both the casting alloy and the die material and is equal to the solidus temperature of the resulting alloy. The critical temperature is used to predict the onset of die soldering, and the local liquid fraction is related to the soldering tendency. Experiments have been carried out to validate the concept and to determine the critical temperature for die soldering in an iron-aluminum system. Thermodynamic calculations are used to determine the critical temperature and soldering tendency for the cases of pure aluminum and a 380 alloy in a steel mold. Factors affecting the soldering tendency are discussed, and methods for reducing die soldering are suggested.     

Super-multi-fibre PLC connector utilising angled connection between PLC and tens of fibres

A novel super-multi-fibre planar lightwave circuit (PLC) connector, designed to connect tens of optical fibres and a PLC for super-multichannel PLC-based optical modules with a receptacle interface, is proposed. This connector employs an angled connection instead of a PC connection. A 0.127 mm pitch 32-fibre connector is also demonstrated, which exhibits low connection and high return losses.     

Enhanced Photoelectrochemistry in CdS/Au Nanoparticle Bilayers

Three different configurations of Au‐nanoparticle/CdS‐nanoparticle arrays are organized on Au/quartz electrodes for enhanced photocurrent generation. In one configuration, Au‐nanoparticles are covalently linked to the electrode and the CdS‐nanoparticles are covalently linked to the bare Au‐nanoparticle assembly. The resulting photocurrent, φ = 7.5 %, is ca. 9‐fold higher than the photocurrent originating from a CdS‐nanoparticle layer that lacks the Au‐nanoparticles, φ = 0.8 %. The enhanced photocurrent in the Au/CdS nanoparticle array is attributed to effective charge separation of the electron–hole pair by the injection of conduction‐band electrons from the CdS‐ to the Au‐nanoparticles. Two other configurations involving electrostatically stabilized bipyridinium‐crosslinked Au/CdS or CdS/Au nanoparticle arrays were assembled on the Au/quartz crystal. The photocurrent quantum yields in the two systems are φ = 10 % and φ = 5 %, respectively. The photocurrents in control systems that include electrostatically bridged Au/CdS or CdS/Au nanoparticles by oligocationic units that lack electron‐acceptor units are substantially lower than the values observed in the analogous bipyridinium‐bridged systems. The enhanced photocurrents in the bipyridinium‐crosslinked systems is attributed to the stepwise electron transfer of conduction‐band electrons to the Au‐nanoparticles by the bipyridinium relay bridge, a process that stabilizes the electron–hole pair against recombination and leads to effective charge separation.     

Hf-doped and NH/sub 3/-nitrided high-K gate dielectric thin film with least drain current degradation and flatband voltage shift

A novel technique to form high-K dielectric of HfSiON by doping base oxide with Hf and nitridation with NH/sub 3/, sequentially, is proposed. The HfSiON gate dielectric demonstrates excellent device performances such as only 10% degradation of saturation drain current and almost 45 times of magnitude reduction in gate leakage compared with conventional SiO/sub 2/ gate at the approximately same equivalent oxide thickness. Additionally, negligible flatband voltage shift is achieved with this technique. Time-dependent dielectric breakdown tests indicate that the lifetime of HfSiON is longer than 10 years at V/sub dd/=2 V.