We have computationally explored the chemical structures of carbon-doped silicon oxide (SiOCH) films that give the smallest dielectric constant (k) under the required mechanical strength for low-k dielectrics. The focus of this study is on the SiOCH structures that have hydrocarbon components in the polymer network as cross-links. It has been found that SiOCH films of small dielectric constants can have improved mechanical strengths if the hydrocarbon components form cross-links, instead of the terminal methyl groups in the conventional structure. The calculated results suggest that SiOCH films of ideal structures can have substantially smaller dielectric constants than films of current interconnect technology with the same mechanical strengths.
We introduce III-V nitrides growth including GaN as well as InGaN by a newly developed atmospheric-pressure metal-organic vapor phase epitaxy system with a three layered flow channel which is a promising system for a large scale production. First, we have shown through computer simulation that a laminar flow of gases is maintained at 1000 °C in the three layered flow channel. Second, as a part of epitaxial results, we have found that the surface roughness of a low temperature-grown buffer layer on sapphire substrates, which can be measured by atomic force microscope, should be minimum in order to grow high quality GaN. We also report the growth of a double heterostructure of Ino. 15Gao.85N/GaN which shows a strong near band-edge emission in room temperature photoluminescence.
Previous work on a slowly rotating mass shell with Rat interior in a Friedman" universe is extended to second order in the angular velocity w. The rotational perturbations of order w lead to density perturbations and gravihdonal waves in the perturbed Friedman" cosmos of order w2, The density perturbations are discussed with the help of gauge-invariant variables. It is shown that the flatness condition inside the shell can be preserved in order wz if the geameuy of the shell is suitably chosen, though there are gravitational waves in the exterior region. The deformation of the shell is discussed for the very early and late stlges of the universe. PACS numbers: 04201,0430, 9880 t Present address: Max-Planck-Gesellschfc Arkitsgruppe Gravitationstheorie an der Univenilar Iena, Max-Wen-Platz 1. D-07743 ]en& Federal Republic of Germany.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.