1998 Fiscal Year Final Research Report Summary
Mechanism of synchrotron radiation etching of diamonds
| Project/Area Number |
09450021
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
表面界面物性
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
ISHIGURO Eiji University of the Ryukyus, College of Education, Professor, 教育学部, 教授 (40047288)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Diamond / Core excitation / Synchrotron radiation / Microfabrication / Etching / Surface reaction / 光脱離 |
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| Research Abstract |
The surface of diamond can be etched in the atmosphere of oxygen by irradiation of synchrotron radiation(SR). The measured etch rate was constant independently of the temperature of the diamond sample and a typical value of the etch rate was 0.13 A/mA min in the pressure 0.1 torr of oxygen with non-dispersed SR.This means that a photoexcitation process is essential in the SR etching of diamond. Photon energy dependence of the etch rate was investigated with a thin film filter of carbon. The k-shell excitation of carbon atoms of diamond resulted in an extremely high etch rate compared with the valence electron excitation. This indicates that Knotek-Feibelman model for photodesorption from surface is also applied to the SR etching of diamond.
NO_2 and H_20 were used as etchant besides 0_2. The etch rate was 0.15 A/mA 1mm for NO_2 in the pressure of 0.1 torr and 0.08 A/Ma/min for H_20. No difference can be seen between NO_2 and 0_2 and the rate for H_20 was almost a half of those of NO_2 and 0_2. The result demonstrates that the etch rate is strongly dependent on the concentration of atomic oxygen dissociated by irradiation of SR but not on the properties of the molecules. To obtain a high concentration of atomic oxygen, a radical generator by means of microwave discharge was used. When the pressure in the reaction chamber was 1 X 10^4 torr, the etch rate was 0.16 A/Ma/min which was remarkably high compared with those for molecular gases, considering a large difference of the pressure in the chamber, Conclusively, the mechanism of etching by SR is considered as follows ; when the surface of diamond is irradiated with SR, multiple holes are produced in the atomic layers by core excitation accompanied with the Auger processes and then carbon atoms are removed from the surface as volatile matter of CO or CO_2 by combined with atomic oxygen existing near the surface.
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Research Products
(12 results)
