ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

structure structure (solids and liquids) D 2000 -025Reduction of Magnesium Orthovanadate Mg 3 (VO 4 ) 2 .-A single crystal of orthorhombic Mg 3 V 2 O 8 (cation-deficient-spinel structure) is transformed into cubic Mg 3 V 2 O 6 (space group Fd-3m, Z = 8) at 560 • C in 7% H 2 /N 2 . Polycrystalline Mg 3 V 2 O 6 can be readily reoxidized to Mg 3 V 2 O 8 in air or oxygen at 500 • C. Single crystal X-ray diffraction analysis shows that Mg 3 V 2 O 6 has a spinel structure with an excess of cations (cation-stuffed-spinel structure). -(WANG, X.; ZHANG, H.; SINKLER, W.; POEPPELMEIER, K. R.; MARKS, L. D.; J. Alloys Compd. 270 (1998) 1-2, 88-94; Dep. Chem., Northwest. Univ., Evanston, IL 60208, USA; EN)

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

TiN diffusion barriers have been widely used in submicron contact structures, due to its good adhesion (to SiO2, W, Al and Si) properties, low diffusivity (for Si, W and Al) and compatibility with TiSi2 processing. The purpose of this paper is to present the results of physical and electrical characterization of contact structures with a TiN barrier and W plugs. Two different barrier metal processes were compared, Viz: sputtered Ti followed by post RTN and Ti/TiN films followed by post RTA in the range of 600° to 800°C. The devices were thermal stressed at 450°C for 7 hrs after W plug formation and Al metallization. Ti/TiN films with post RTA are generally superior barrier layers than Ti films with post RTA as shown by electrical characterization of contact resistance and barrier integrity. The relationship between electrical properties and microstructure for the two different barrier structures is discussed. W/TiN and TiN/TiSi2 interface structures were characterized using high resolution TEM. TiSi2 was found to be epitaxially grown during RTA, under certain process conditions. The crystal structure of TiSi2 was determined from electron diffraction patterns.

Synthesis and Structure of LaSr2CuTiO6.5: A New Oxygen-Deficient Ruddlesden-Popper Phase. -The novel title compound LaSr2CuTiO6.5 (I), prepared by solid state reaction at 975 • C, represents an oxygen-deficient (ABO3)nAO (n = 2) Ruddlesden-Popper phase. According to Rietveld analysis of the powder XRD data, in the structure of (I) (tetragonal, I4/mmm) Cu and Ti are disordered over a single B cation site while La and Sr are nearly perfectly disordered over the two A-cation sites. The occurrence of oxygen vacancies in combination with different coordination preferences of the multiple B-cations does not result in a layered structure for (I). Strategies for inducing a layered arrangement of the B-cations are discussed. -(SARJEANT, G. M.; GREENWOOD, K. B.; POEPPELMEIER, K. R.; ZHANG, H.; SALVADOR, P. A.; MASON, T. O.; MARKS, L. D.; Chem.