2005 Fiscal Year Final Research Report Summary
Development of a high-sensitivity, high-resolution hydrogen detection technique and its application to hydrogen impurities in semiconductors
| Project/Area Number |
15310083
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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 |
Nanomaterials/Nanobioscience
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| Research Institution | The University of Tokyo |
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Principal Investigator |
WILDE Markus The University of Tokyo, Institute of Industrial Science, Research Associate, 生産技術研究所, 助手 (10301136)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUTANI Katsuyuki The University of Tokyo, Institute of Industrial Science, Associate Professor, 生産技術研究所, 助教授 (10228900)
OKANO Tatsuo The University of Tokyo, Institute of Industrial Science, Professor, 生産技術研究所, 教授 (60011219)
MURATA Yoshitada The University of Tokyo, Institute for Solid State Physics, Emeritus professor, 物性研究所, 名誉教授 (10080467)
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| Project Period (FY) |
2003 – 2005
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| Keywords | Quantitative hydrogen detection / Nuclear Reaction Analysis (NRA) / Ion beam analysis (IBA) / Semiconductor impurities / Surface analysis / Non-destructive depth profiling |
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| Research Abstract |
The project has thoroughly explored the viability of applying the 2^<nd> energy resonance of the ^1H(^<15>N, αγ)^<12>C reaction at 13.35 MeV for hydrogen depth profiling, aiming to achieve a sensitivity enhancement for the determination of low hydrogen concentrations in bulk samples by ^<15>N nuclear reaction analysis.
By acquisition of excitation curves of the nuclear reaction the 6.385 MeV and 13.35 MeV from the same thin film specimen of 〜40 nm hydrogenated SiN on H-free crystalline Si(100) the investigation has experimentally verified that the integral reaction cross-sections at the broader 13.35 MeV resonance is (8.7±0.2) times as large as that of the more commonly applied sharper resonance at 6.385 MeV. Combined with the 〜10 % reduced stopping power for ^<15>N at the higher resonance energy, this gain of resonant γ-yield corresponds to a sensitivity improvement for the measurement of bulk H concentrations by a factor of 10.
In order to enable the evaluation of sensitivity restricti
… More
ons imposed by non-resonant reaction yield from hydrogen in surface layers, the off-resonance cross section of the ^1H(^<15>N, αγ)^<12>C reaction in the entire energy range from 6-16 MeV was determined quantitatively. This information is indispensable to estimate the maximum surface hydrogen contamination levels that are tolerable in a given analytical task defined by the stopping power of the target material and the required probing depth. Practical recommendations to overcome possible limitations due to surface contamination have been devised.
The study further revealed that background corrections of the γ-detector output are essential at ^<15>N ion energies exceeding 〜8 MeV due to emission of non-specific continuous γ-radiation. This effect has barely been pointed out in the respective literature so far. In addition the project has lead to the development of a versatile software package capable of simulating experimental NRA yield curves, which proved to be invaluable for the establishment of the off-resonant reaction cross section by enabling the distinction of resonant and non-resonant reaction yield. It furthermore significantly helps interpreting experimental NRA yield curves in terms of the underlying hydrogen depth profile. The developed methods of analysis are universal and considered to be applicable to a large number of NRA investigations benefiting from the enhanced sensitivity of the 13.35 MeV resonance. Quantitative analysis of surface hydrogen using a unique form of zero-point vibrational spectroscopy by NRA has also been achieved. Less
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Research Products
(8 results)
