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'copper' in keywords Facet   Publication Year 1997  [X]
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1997[X]
1Author    Valerie Bertagna, Francis Rouelle, Marius ChemlaRequires cookie*
 Title    Copper Contamination Mechanism of Silicon Substrates from HF Solutions  
 Abstract    The contamination of silicon wafers from dilute HF solutions containing ultratrace levels of metallic ion impurities is a subject of constant interest. The mechanism of copper electroless deposition from HF onto monocrystalline silicon was investigated using a new electrochemical cell, which proved to be a very sensitive detector for in situ characterization of silicon surfaces. Upon addition of copper trace amounts, the open-circuit potential was observed to shift rapidly towards more positive values at a rate nearly proportional to the copper concentration. All poten-tial/time curves tend to reach a limiting value of the potential, while quantitative measurements of radioactive tracers revealed that during a few tens of minutes, copper ions were continuously reduced on the silicon surface. Electrochemical potentials and voltammetric measurements were interpreted in terms of the mixed potential theory and led to the conclusion that copper nuclei act as a catalyst which enhances the cathodic activity for protons reduction. The model was supported by AFM observations which demonstrated the initiation of corrosion pits around the nuclei. 
  Reference    Z. Naturforsch. 52a, 465—176 (1997); received April 14 1997 
  Published    1997 
  Keywords    Silicon, contamination, copper, catalysis 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0465.pdf 
 Identifier    ZNA-1997-52a-0465 
 Volume    52 
2Author    Hk Wulff, Müller-BuschbaumRequires cookie*
 Title    Planare C u 0 4-Polygone und eine einseitig offene Te4+0 3-Koordination in SrCuTe20 6 Planar C u 0 4 Polygons and a One-Sided Open Te4+0 3 Coordination in SrCuTe-,06 L  
 Abstract    The new compound SrCuTe20 6 has been prepared by quenching single crystals grown from a flux of SrC 03, T e02 and C uC 03 C u(0H)2. X-ray investigations show cubic symmetry, space group 0 7-P4| 32, lattice constant a = 12.473(1), Z = 12. The crystal structure is characterized by square planar C u 0 4 polygons and a one-sided open triangular oxygen coordination of Te4+, both incorporated in a Sr/O network. The one sided oxygen coordination of tellurium is completed by the lone pair of Te4+. Calculations of the Coulomb parts of lattice energy led to the position of the lone pair centre. 
  Reference    Z. Naturforsch. 52b, 1341—1344 (1997); eingegangen am 26. August 1997 
  Published    1997 
  Keywords    Strontium, Copper, Tellurium Oxide, Crystal Structure 
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 TEI-XML for    default:Reihe_B/52/ZNB-1997-52b-1341.pdf 
 Identifier    ZNB-1997-52b-1341 
 Volume    52