2007 Fiscal Year Final Research Report Summary
Evaluation of thin film on metal and semiconductor surface by electroanalytical methods and certification of thin film standards for surface analysis
| Project/Area Number |
17550086
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Analytical chemistry
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| Research Institution | Tokyo University of Science |
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Principal Investigator |
TANAKA Tatsuhiko Tokyo University of Science, Faculty of Engineering, Professor (40084389)
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| Project Period (FY) |
2005 – 2007
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| Keywords | characterization and evaluation / galvanized steel sheet / silicon wafer / thin film reference materials / chemical analysis |
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| Research Abstract |
Precise electroanalytical methods have been developed for the evaluation of galvanized steel sheet and silicon wafer. The proposed methods are successfully applicable to certify thin film reference materials for surface analysis.
1. Measurement of zinc deposits on galvanized steel sheet
A galvanized steel sheet sample was decomposed with an acid mixture on heating. To the solution was added L (+)-ascorbic acid in order to reduce matrix iron (III) to iron (II) ; pH of the solution was then adjusted to 4. The solution was then diluted to a definite volume with a dilute acid mixture pre-adjusted to pH 4. Zinc (II) in the sample solution was electrodeposited into a hanging mercury drop electrode at -1.15 V vs. Ag/AgC1 for 20 min. The deposits were then stripped at a scan rate of 50 mV/s to -0.7 V vs. Ag/AgC1. The zinc film thickness at the pm level on a galvanized steel sheet was measured with good precision by anodic stripping voltammetry.
The thickness was measured also by stripping coulometry, which involves the complete electrodeposition of zinc(II) in the sample solution, followed by stripping of the deposits and measurement of quantity of electricity (area). The amounts of zinc deposits linked to SI units can be obtained by this definitive method.
2. Measurement of thickness of silicon dioxide film on silicon wafer surface
Silicon dioxide film on silicon wafer surfaces was dissolved in a dilute hydrogen fluoride solution. A complex of silicon(PV) with hexaammonium heptamolybdate, P-silicododecamolybdate, was adsorbed electrolytically on a glassy carbon electrode at -1.0 V vs. Ag/AgC1 for 10 min. The deposits were then stripped by a positive-going scan to -0.3 V vs. Ag/AgC1 at a rate of 50 mV/s. Adsorptive stripping voltammetry is applicable to the measurement of 1 to 100 nm of the film thickness.
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