Hemispherical grained Si formation on in-situ phosphorus dopedamorphous-Si electrode for 256 Mb DRAM's capacitor

The cylindrical capacitor structure with hemispherical grained-Si (HSG-Si) described here reliably achieves a cell capacitance of 30 fF in a 0.4 μm-high storage electrode with a cell area of a 0.72 μm² for 256 Mbit dynamic random access memory. An HSG-Si formation technology using Si₂H₆-molecule irradiation and annealing enables control of the grain density and grain size of HSG-Si fabricated selectively on the whole surface of phosphorus-doped amorphous Si cylindrical electrodes     

The effect of excess gate current on input impedance of a JFET amplifier

When JFET is used as an amplifier, it should be regarded that the effect of excess gate current on the input impedance is changed by gain of the amplifier. The input impedance or conductance with gain of the JFET amplifier is experimentally analyzed applying small signal equivalent circuit.     

Preparation and catalytic activity of Au-Pd, Au-Pt, and Pt-Pd binary metal dendrimer nanocomposites

Catalytic activity of Au-Pt, Au-Pd, and Pt-Pd dendrimer nanocomposites for reduction of p-nitrophenol was investigated in water. The bimetallic dendrimer nanocomposites were prepared by simultaneous reduction with sodium borohydride in the presence of poly(amidoamine) (PAMAM) dendrimers with amine and carboxyl terminal groups. Average diameters of the obtained particles were 2-4 nm by transmission electron microscopy. From UV-vis spectroscopy, it was found that the particles were not mixtures of monometallic particles but binary ones. X-ray photoelectron spectroscopy showed that formation of binary composite particles prevents palladium atoms from oxidation. The Au-Pd and Pt-Pd binary particles exhibited higher catalytic activity than monometallic ones. On the other hand, catalytic activity of Au-Pt binary particle was comparable to that of platinum nanoparticles.     

Silicon carbide coating on molybdenum by chemical vapor deposition and its stability under thermal cycle conditions

Silicon carbide film (as thick as 25 μm) was chemically vapor deposited on molybdenum in the temperature range of 1050–1300°C by reaction of hydrogen and ethyltrichlorosilane as an application of a low-Z material to fusion reactor protective plates. The films were characterized by using scanning electron microscopy, X-ray diffraction, electron microprobe analysis, and infrared absorption spectroscopy. The deposits consisted of α and β-SiC and a small amount of SiO₂. Underlayer coatings were also attempted to improve the thermal cycling behavior. The coating with a boron underlayer was successfully cycled 2100 times between 800 and 1000°C, and then 560 times between 600 and 1200°C in air under thermal cycling conditions with a heating rate of 20°C/min. Problems in applying SiC-coated molybdenum to the first wall protective plates in a fusion reactor are discussed.