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Spin polarized ion beam generation apparatus and scattering spectroscopy apparatus using the spin polarized ion beam and specimen processing apparatus 新技術説明会

外国特許コード F110005397
整理番号 K02208WO
掲載日 2011年9月5日
出願国 アメリカ合衆国
出願番号 51635107
公報番号 20100044564
公報番号 8017920
出願日 平成19年11月29日(2007.11.29)
公報発行日 平成22年2月25日(2010.2.25)
公報発行日 平成23年9月13日(2011.9.13)
国際出願番号 JP2007073121
国際公開番号 WO2008069110
国際出願日 平成19年11月29日(2007.11.29)
国際公開日 平成20年6月12日(2008.6.12)
優先権データ
  • 特願2006-321044 (2006.11.29) JP
  • 特願2007-190277 (2007.7.23) JP
  • 2007JP073121 (2007.11.29) WO
発明の名称 (英語) Spin polarized ion beam generation apparatus and scattering spectroscopy apparatus using the spin polarized ion beam and specimen processing apparatus 新技術説明会
発明の概要(英語) A spin polarized ion beam generation apparatus (30) can efficiently generate a spin polarized ion by using a pumping light generator (33) to an ion in a high frequency discharge tube (15) to irradiate optical pumping (33,34) by circularly polarized light and linearly polarized light orthogonal to each other to a metastable atom.
For example, a polarized helium ion beam having a spin polarization rate that exceeds 18% and that is as high as 25% can be generated.
The spin polarized ion beam generation apparatus (30) also can be applied to a processing apparatus and an analysis apparatus that can irradiate a polarized ion beam to a specimen.
According to the spin polarized ion scattering spectroscopy apparatus, the spin status in a region at a depth of about 2 to 3 atomic layers from the surface of the specimen can be measured while discriminating the elements from the atomic layer with a reduced measurement time and with a high accuracy impossible in the conventional technique.
従来技術、競合技術の概要(英語) BACKGROUND
Non Patent Document 1 reported that the spin polarized helium ion is generated by Penning ionization of optical pumped metastable helium atom (He*(23S1)).
The Penning ionization is represented by the following reaction formula (1),
He*+He*-->He++He+e- (1)
where He* represents a metastable helium atom, He+ represents a monovalent helium cation, and e- represents an electron.
In this reaction, a spin angular momentum component of helium is conserved.
Thus, when metastable helium atom (He*) is subjected to an optical pumping and is spin polarized, then an electron of the generated helium ion (He+) is also spin polarized.
In the present invention, such an ion is called a polarized ion or a spin polarized ion.
In the case of a method of using the polarized ion beam to inspect the magnetic property of the surface and interface of material, the measurement time must be minimized in order to prevent the surface contamination during the measurement because the polarized ion beam is very sensitive to the surface.
Conventionally, as disclosed in Non Patent Document 2, the polarization of a helium ion has been provided by an optical pumping using circularly polarized light having a wavelength of the D1 line corresponding to the transition of metastable helium atom 23S1 to 23P1.
Techniques for using circularly polarized light and linearly polarized pumping light that are orthogonal to each other to generate a spin polarized electron out of a metastable helium atom are disclosed in Non Patent Documents 3 and 4.
This conventional technique provides a polarization rate of a helium ion of 18%.
A polarized helium ion having a polarization rate equal to or higher than 18% has been impossible.
Thus, it was difficult to prevent the surface contamination during the measurement, and there has been the limitation on the measurement result.
In a processing such as a surface reforming by using polarized ion beam, there has caused a limitation of processing accuracy due to the low polarization rate of the polarized ion beam.
The analysis for the identification of elements of the magnetic structure is possible by using the conventional techniques such as neutron scattering (Non Patent Document 5) and magnetic circular dichroism spectroscopy (Non Patent Document 6).
However, these techniques are not sensitive to the surface of analyzed specimen, it was impossible to analyze the magnetic structure limited to a few atomic layers of the surface.
On the other hand, the conventional techniques such as the spin polarized photoelectron spectroscopy (Non Patent Document 7) and the spin polarized metastable atom deexcitation spectroscopy (Non Patent Document 8) have the sensitivity to the surface.
Since these techniques have no capability to identify elements, it is impossible to analyze the magnetic structure by discriminating an element from an atomic layer.
As described above, the conventional techniques could not provide an analysis of the magnetic structure by discriminating the elements in a few atomic layers of the surface.
Furthermore, it was possible to analyze the composition and structure of the surface and interface by the conventional ion scattering spectroscopy (Non Patent Document 9).
However, an analysis of the spin in the surface and interface of a specimen could not be achieved.
In other words, while the elucidation of the magnetic structure of the surface and interface has been important in the development of new devices, it has been impossible to analyze to select elements from the outermost surface of about 2 to 3 atomic layers by using the conventional analysis techniques.
Non Patent Document 1: L. D. Schearer, Physical Review Letters, 22, (1969), 629.
Non Patent Document 2: D. L. Bixler, Review of Scientific Instruments, 70, (1999), 240.
Non Patent Document 3: S. Essabaa et al., Nuclear Instruments and Methods in Physics Research, A334, (1994), 315-318.
Non Patent Document 4: L. D. Schearer et al., Physical Review A, Vol. 42, No. 7, (1 Oct. 1990), 4028-4031.
Non Patent Document 5: C. G. Shull et al., Physical Review, 84, (1951), 912.
Non Patent Document 6: Makoto Imada, Butsuri (Membership Journal of the Physical Society of Japan), 55, (2000), 20.
Non Patent Document 7: P. D. Johnson et al., Journal of Physics, Condensed Matter, 10, (1998), 95.
Non Patent Document 8: M. Onellion et al., Physical Review Letters, 52, (1984), 380.
Non Patent Document 9: D. P. Smith, Journal of Applied Physics, 38, (1967), 340.
Non Patent Document 10: W. Happer, Review of Modern Physics, 44, (1972), 169.
Non Patent Document 11: M. Aono and R. Souda, Japanese Journal of Applied Physics, 24, (1985), 1249.
Non Patent Document 12: Taku Suzuki, Extended Abstracts of the 53rd Spring Meeting, The Japan Society of Applied Physics and Related Societies, Tokyo, No. 2, (2006), 782.
Non Patent Document 13: R. Souda et al., Surface Science, 179, (1987), 199.

特許請求の範囲(英語) [claim1]
1. A spin polarized ion beam generation apparatus comprising: a high frequency discharge tube for ion generation;
a laser oscillator; and
a pumping light generator that divides a laser light from said laser oscillator to two lights of a circularly polarized first pumping light and a linearly polarized second pumping light to emit these lights to said high frequency discharge tube with an irradiation angle difference of 90 degrees therebetween, wherein
an extraction electrode for extracting a polarized ion is provided to said high frequency discharge tube.
[claim2]
2. The spin polarized ion beam generation apparatus as set forth in claim 1, wherein said polarized ion beam is extracted in a direction orthogonal to both of said circularly polarized light and said linearly polarized light.
[claim3]
3. The spin polarized ion beam generation apparatus as set forth in claim 1, wherein said high frequency discharge tube includes a repeller electrode opposed to said extraction electrode.
[claim4]
4. The spin polarized ion beam generation apparatus as set forth in claim 3, wherein said extraction electrode includes a fine pore.
[claim5]
5. The spin polarized ion beam generation apparatus as set forth in claim 1, wherein said pumping light generator includes a circularly polarized light controller that controls said circularly polarized first pumping light in a clockwise or a counterclockwise direction.
[claim6]
6. The spin polarized ion beam generation apparatus as set forth in claim 1, wherein said laser oscillator outputs a laser light with a wavelength adjusted so that a polarization rate of a metastable atom as a base of an ion is maximum, said polarization rate being calculated by a measurement of absorption of a probe laser.
[claim7]
7. The spin polarized ion beam generation apparatus as set forth in claim 1 or 6, wherein said ion is a helium ion, said first and second pumping lights have a wavelength of a D0 line, and said probe light has a wavelength of a D0 line that is circularly polarized light in a counterclockwise or clockwise direction.
[claim8]
8. The spin polarized ion beam generation apparatus as set forth in claim 1 or 3, wherein said high frequency discharge tube has therein a helium pressure of 15 Pa or more and 50 Pa or less.
[claim9]
9. A spin polarized ion scattering spectroscopy apparatus comprising: a spin polarized ion beam generator;
a spin polarized ion beam line that irradiates a spin polarized ion beam generated from said spin polarized ion beam generator to a specimen; and
a measurement section that measures energy of ions scattered by interaction of said specimen with said spin polarized ion beam, wherein
said spin polarized ion beam generator including:
a high frequency discharge tube for ion generation;
a laser oscillator; and
a pumping light generator that divides a laser light from said laser oscillator to two lights of a circularly polarized first pumping light and a linearly polarized second pumping light to emit these lights to said high frequency discharge tube with an irradiation angle difference of 90 degrees therebetween, wherein
an extraction electrode for extracting said polarized ion is provided to said high frequency discharge tube.
[claim10]
10. The spin polarized ion beam generation apparatus as set forth in claim 9, wherein said polarized ion beam is extracted in a direction orthogonal to both of said circularly polarized light and said linearly polarized light.
[claim11]
11. The spin polarized ion scattering spectroscopy apparatus as set forth in claim 9, wherein said high frequency discharge tube includes a repeller electrode opposed to said extraction electrode.
[claim12]
12. The spin polarized ion scattering spectroscopy apparatus as set forth in claim 11, wherein said extraction electrode includes a fine pore.
[claim13]
13. The spin polarized ion scattering spectroscopy apparatus as set forth in claim 9, wherein said pumping light generator includes a circularly polarized light controller that controls a circularly polarized light of said first pumping light in a clockwise or a counterclockwise direction.
[claim14]
14. The spin polarized ion scattering spectroscopy apparatus as set forth in claim 9, wherein said laser oscillator outputs a laser light with a wavelength adjusted so that a polarization rate of a metastable atom as a base of an ion is maximum, said polarization rate being calculated by a measurement of absorption of a probe laser.
[claim15]
15. The spin polarized ion scattering spectroscopy apparatus as set forth in claim 9, further comprising: a specimen stage that can control an incident angle to a spin polarized ion entering said specimen.
[claim16]
16. The spin polarized ion scattering spectroscopy apparatus as set forth in claim 9, wherein said spin polarized ion beam line includes a lens having a fine pore functioning as an evacuation hole and said lens is made of a non magnetic material.
[claim17]
17. The spin polarized ion scattering spectroscopy apparatus as set forth in claim 9 or 14, wherein said ion is a helium ion and said first and second pumping lights have a wavelength of a D0 line.
[claim18]
18. A spin polarized ion scattering spectroscopy using the spin polarized ion scattering spectroscopy apparatus according to any of claims 9 to 16 comprising: a step of causing spin polarized ion to enter a specimen;
a step of measuring scattered ions from said specimen; and
a step of measuring scattered ion intensities with regard to respective spins of incident ion species to analyze a magnetic structure of a surface of said specimen based on a dependency of said specimen on a spin of a probability at which an ion enters said specimen is neutralized.
[claim19]
19. The spin polarized ion scattering spectroscopy as set forth in claim 18 further comprising: a step of detecting the scattered ion intensity by an electrostatic analyzer to analyze a magnetic structure of a surface said a specimen based on a difference in the scattered ion intensity depending on a direction of a spin of said ion.
[claim20]
20. The spin polarized ion scattering spectroscopy as set forth in claim 18, further comprising: a step of measuring a dependency of said scattered ion intensity on an incident angle of said spin polarized ion to said specimen; and a step of analyzing a spin while discriminating, based on the measurement of said scattered ion intensity, an atomic layer from an element in a direction of the depth from a surface of said specimen.
[claim21]
21. The spin polarized ion scattering spectroscopy as set forth in claim 18 further comprising: a step of analyzing a magnetic structure of a surface of said specimen based on a detected amount by an electrostatic analyzer before and after changing a direction of a spin of said spin polarized ion.
[claim22]
22. A specimen processing apparatus using spin polarized ion beam comprising: a spin polarized ion beam generator;
a spin polarized ion beam line that irradiates a spin polarized ion beam generated from said spin polarized ion beam generator to a specimen; and
an ultrahigh vacuum chamber that is irradiated a shaped spin polarized ion beam from said spin polarized ion beam line to said specimen thereof, wherein
said spin polarized ion beam generator including:
a high frequency discharge tube for ion generation;
a laser oscillator; and
a pumping light generator that divides a laser light from said laser oscillator to two lights of a circularly polarized first pumping light and a linearly polarized second pumping light to emit these lights to said high frequency discharge tube with an irradiation angle difference of 90 degrees therebetween, wherein
an extraction electrode for extracting said polarized ion is provided to said high frequency discharge tube.
[claim23]
23. The specimen processing apparatus using spin polarized ion beam as set forth in claim 22, wherein said polarized ion beam is extracted in a direction orthogonal to both of said circularly polarized light and said linearly polarized light.
[claim24]
24. The specimen processing apparatus using spin polarized ion beam as set forth in claim 22, wherein said high frequency discharge tube includes a repeller electrode opposed to said extraction electrode.
[claim25]
25. The specimen processing apparatus using spin polarized ion beam as set forth in claim 22, wherein said extraction electrode includes a fine pore.
[claim26]
26. The specimen processing apparatus using spin polarized ion beam as set forth in claim 22, wherein said pumping light generator includes a circularly polarized light controller that controls a circularly polarized light of said first pumping light in a clockwise or a counterclockwise direction.
[claim27]
27. The specimen processing apparatus using spin polarized ion beam as set forth in claim 22, wherein said laser oscillator outputs laser light with a wavelength adjusted so that a polarization rate of a metastable atom as a base of an ion is maximum, said polarization rate being calculated by a measurement of absorption of a probe laser.
[claim28]
28. The specimen processing apparatus using spin polarized ion beam as set forth in claim 22, further compring: a specimen stage that can control an incident angle to said spin polarized ion entering said specimen.
[claim29]
29. The specimen processing apparatus using spin polarized ion beam as set forth in claim 22, wherein said spin polarized ion beam line includes a lens having a fine pore functioning as an evacuation hole and said lens is made of non magnetic material.
[claim30]
30. The specimen processing apparatus using spin polarized ion beam as set forth in claim 22 or 26, wherein said ion is a helium ion and said first and second pumping lights have a wavelength of a D0 line.
  • 発明者/出願人(英語)
  • SUZUKI TAKU
  • YAMAUCHI YASUSHI
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
国際特許分類(IPC)
米国特許分類/主・副
  • 250/423.000R
  • 250/281
  • 250/288
  • 250/305
  • 250/309
  • 250/423.000P
  • 250/424
  • 250/425
参考情報 (研究プロジェクト等) PRESTO Structure Function and Measurement Analysis AREA
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