Decomposition of trimethylgallium (TMG) and triethylgallium (TEG) in hydrogen and nitrogen atmospheres was studied by a quadrupole mass analyzer. The decomposition reactions of TMG in H2 and in N2 and of TEG in H2 and in N2 take place in the temperature ranges 370°–460°, 450°–570°, 220°–330°, and 270°–380°C, respectively. The reaction mechanisms are hydrogenolysis for TMG in H2 , homolytic fission for TMG in N2 , and β elimination for TEG in both H2 and N2 . The hydrogenolysis of TMG follows homogeneous first‐order kinetics on TMG concentration.

GaAs/GaAsBi coaxial multishell nanowires were grown by molecular beam epitaxy. Introducing Bi results in a characteristic nanowire surface morphology with strong roughening. Elemental mappings clearly show the formation of the GaAsBi shell with inhomogeneous Bi distributions within the layer surrounded by the outermost GaAs, having a strong structural disorder at the wire surface. The nanowire exhibits a predominantly ZB structure from the bottom to the middle part. The polytipic WZ structure creates denser twin defects in the upper part than in the bottom and middle parts of the nanowire. We observe room temperature cathodoluminescence from the GaAsBi nanowires with a broad spectral line shape between 1.1 and 1.5 eV, accompanied by multiple peaks. A distinct energy peak at 1.24 eV agrees well with the energy of the reduced GaAsBi alloy band gap by the introduction of 2% Bi. The existence of localized states energetically and spatially dispersed throughout the NW are indicated from the low temperature cathodoluminescence spectra and images, resulting in the observed luminescence spectra characterized by large line widths at low temperatures as well as by the appearance of multiple peaks at high temperatures and for high excitation powers.

The mechanism of particle generation is investigated in order to prevent defects formed on wafers in the plasma etching of multi-layered films composed of tungsten silicide (WSi) and polycrystalline silicon (poly-Si). Particles are measured by an in situ monitoring system using laser light scattering during the etching process. The particles are composed of AlF 3 , which is presumably generated by reacting the coating material Al 2 O 3 on the etching chamber wall with plasma containing fluorine atoms, F in the presence of H 2 O absorbed into the chamber parts and materials. We demonstrated successfully that dehydration of the chamber parts and materials by plasma discharge suppresses particle generation.

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To elucidate the mechanism of instantaneous generation of many flaked particles in plasma etching equipment, we investigate the relationship between the generation of flaked particles from deposited films (consisting of etching reaction products on the ground electrode) and the plasma stability under mass-production conditions. Many particles are observed with our particle monitoring system when plasma instability occurs. The generation of such flaked particles correlates well with the occurrence of a large, rapid change in floating potential on the chamber wall. Our results indicate that many flaked particles from films deposited on a ground electrode are generated by electric field stress acting instantaneously and working as an impulsive force. #