| | 1 | Author
| Valerie Bertagna, Francis Rouelle, Marius Chemla | Requires 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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| default:Reihe_A/52/ZNA-1997-52a-0465.pdf | | | | Identifier
| ZNA-1997-52a-0465 | | | | Volume
| 52 | |
| 2 | Author
| WolfgangK. Läuia, Susanne Schoger2, Martin Niegerb | Requires cookie* | | | Title
| Synthesis and Crystal Structure of Perhydro-l,4-benzoxazino[2,3-n]phenoxazine | | | | Abstract
| The oxidation of fra«s-2-aminocyclohexanol with nitrobenzene in the presence of catalytic amounts of iron inter alia yields perhydro-l,4-benzoxazino[2,3-n]phenoxazine (1). This com pound has been characterized analytically, spectroscopically and by X-ray diffraction. It is postulated that the oxidation of the 2-aminoalcohol leads to the intermediate formation of a 1,2-dione. The direct synthesis of 1 from trans-2-aminocyclohexanol and 1,2-cyclohexandione supports this hypothesis. | | | |
Reference
| Z. Naturforsch. 52b, 801—804 (1997); eingegangen am 14. Oktober 1996 | | | |
Published
| 1997 | | | |
Keywords
| Nitrobenzene, Reduction, Aniline, 2-Aminoalcohols, Catalysis | | | |
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| default:Reihe_B/52/ZNB-1997-52b-0801.pdf | | | | Identifier
| ZNB-1997-52b-0801 | | | | Volume
| 52 | |
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