JP3135733B2 - Spectral element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectroscopic element for selecting soft X-rays necessary for an apparatus for analyzing, with high sensitivity, the chemical state, chemical composition, and impurity concentration of various materials such as semiconductor materials. The present invention relates to an X-ray spectroscopic element required for an X-ray microscope for microfabrication, for LSI and LSI, an X-ray microscope for living body observation, plasma observation, and the like, and an X-ray telescope for sun corona observation.

[0002]

2. Description of the Related Art There are a diffraction grating, a multilayer film, and a monomolecular crystal as devices for dispersing soft X-rays. However, each spectroscopic element has the following disadvantages.

(1) When a diffraction grating is used for analysis such as ordinary photoelectron spectroscopy, the wavelength resolution λ / Δλ is 100.
At about 10 to 30 ° soft X-ray wavelength, which is extremely high, the ratio of the light intensity of the desired wavelength after the spectrum called the diffraction efficiency to the light intensity before the spectrum, which is called diffraction efficiency, is as low as about 1% and high sensitivity is required. It is not suitable for the spectroscopic experiment performed.

(2) Although the diffraction efficiency of a multilayer film is as high as about several tens of percent, the wavelength resolution of dispersed light is 40 to 40%.
Since it shows a low value of about 60, there is a problem that it is not suitable for experiments requiring high-resolution analysis instead of high sensitivity.

(3) Since monolayer crystal is produced by the LB method, it is difficult to produce a crystal having good crystallinity. Therefore, the diffraction efficiency is lower than that of the diffraction grating, and the wavelength resolution is lower than that of the diffraction grating. In addition, there is a problem that it is extremely weak to heat.

[0006]

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above-mentioned problems, and has realized high resolution and diffraction efficiency at the same time, such as application of spectral analysis utilizing X-rays and soft X-rays. It is an object of the present invention to provide a spectroscopy element that is suitably used for:

[0007]

In order to achieve the above object, a spectroscopic element according to the present invention is characterized by comprising a metal-encapsulated fullerene crystal. By using the metal-encapsulated fullerene crystal, the lattice constant can be increased and the diffraction efficiency can be increased.

[0008]

In general, a multilayer film is formed by alternately stacking heavy element layers and light element layers of about 10 to several tens of degrees with a constant layer thickness. The thickness of the heavy element layer and light element layer makes it possible to split a wavelength of several tens of degrees.
Actually, several tens to about 200 layers are manufactured depending on the thickness of each layer. As the number of layers increases, the wavelength resolution improves, and as the number of layers decreases, the wavelength resolution decreases. In addition, when a multilayer film is manufactured, generally, diffusion occurs slightly at the interface between the light element layer and the heavy element layer, and the steepness of separation of the interface density is reduced, which also causes a decrease in wavelength resolution. .

The crystal has a structure in which a very large number of periodic structures are repeated and the disturbance at the atomic level is extremely small, so that the resolution is high. If such a crystal has a periodic structure in which heavy element layers and light element layers, such as a multilayer film, are alternately arranged at long intervals, the reflectivity and the wavelength are several Å or more compared to conventional crystals. A spectral element having high wavelength resolution is obtained.

[0010] Until now, the crystal has rarely a form in which heavy elements and light elements are alternately laminated, and it has not been possible to use a combination of materials exhibiting high reflectivity in an arbitrary wavelength region.

Recently, molecules and crystals called fullerenes or metal-encapsulated fullerenes have been produced. FIG. 1 shows an example of a metal-encapsulated fullerene molecule. The metal-encapsulated fullerene crystal is composed of La, Y, Sc in a spherical net or a cylindrical net composed of bonds of several tens or more C atoms.
These are regularly arranged three-dimensionally in molecular units including various metals. For this reason, it becomes possible to arrange the included metals regularly at intervals much longer than the lattice constant of a normal crystal without the diffusion of atoms as in a multilayer film. Naturally, if a metal-encapsulated fullerene crystal has a periodic structure in which heavy element layers and light element layers, such as a multilayer film, are alternately arranged at long intervals, the wavelength becomes longer than that of conventional crystals, diffraction gratings, and monomolecular crystals. Is a few square meters or more and the reflectance is high, and
It becomes a spectroscopic element having higher wavelength resolution than a multilayer film or a monomolecular crystal. Therefore, when such a spectroscopic element made of a metal-encapsulated fullerene crystal is applied to various analyzes using, for example, X-rays and soft X-rays, the wavelength resolution of the spectroscopic element and the reflectance are improved, and the sensitivity and accuracy are improved. This has the effect of doing so.

[0012]

Next, typical embodiments of the present invention will be described.

A sample prepared by laminating La ₂ O ₃ and graphite powder is carbonized at 1000 ° C., heat-treated at 1200 ° C., and subjected to YAG in an argon atmosphere.
By irradiating a laser, a metal-encapsulated fullerene was produced. After the La-encapsulated C82 fullerene was separated by chromatography, it was vapor-deposited on a fullerene single-crystal substrate to produce a La-encapsulated C82 fullerene crystal having a thickness of 2 μm, which was used as a spectral element. However, at this stage, the half value width of the diffracted X-ray from the crystal is about 2.7 times that of the C60 single crystal, and the crystal integrity is lower than that of the C60 single crystal. FIG. 2 shows an intensity distribution at a wavelength of 10 ° diffracted by a C82 fullerene crystal containing La, a diffraction grating, and a multilayer film. The vertical axis has the same meaning as the diffraction efficiency because it is normalized by the incident light intensity. As apparent from this figure, the diffraction efficiency of the spectroscopic element of the present invention is 22%.
It is about. This value is equivalent to the diffraction efficiency of the multilayer film in the diffraction efficiency of the diffraction grating and the monomolecular film crystal. In addition, the wavelength resolution is estimated to be about 1100 as estimated from the rocking curve of the diffracted light. This value is higher than the resolution of the multilayer film.

In the above embodiment, C8 containing La is used.
Although only 2 fullerene crystals are shown, the inclusion metal may be any substance, and even if the number of inclusion metals is plural, the number of C bonds may be a fullerene having a number other than that of the examples. Can exhibit the same effect. In addition, it goes without saying that the above-mentioned object can be achieved even in a manufacturing method other than the examples as long as the encapsulated metal fullerene crystal can be obtained without using a substrate.

[0015]

As described above, according to the spectroscopic element of the present invention, high efficiency in the soft X-ray region, which has been incompatible with the prior art, can be obtained.
It has become possible to realize high resolution.

[Brief description of the drawings]

FIG. 1 is a diagram showing a metal-encapsulated fullerene molecule. C atoms exist at the intersections of the stitches.

FIG. 2 is an intensity distribution of diffracted light by a spectroscopic element, a diffraction grating, and a multilayer film according to the present invention.

[Explanation of symbols]

 1 La atom, 2 intensity distribution by the spectroscopic element of the present invention, 3 intensity distribution by the multilayer film, 4 intensity distribution by the diffraction grating.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomoaki Kawamura 1-6-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Inside the Nippon Telegraph and Telephone Corporation (72) Takayoshi Hayashi 1-16-1 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Shoji Ojima 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Japan Nippon Telegraph and Telephone Corporation (72) Yoshikazu Ishii 1-1-1, Uchisaiwaicho, Chiyoda-ku, Tokyo No. 6 Inside Nippon Telegraph and Telephone Corporation (58) Field surveyed (Int. Cl. ⁷ , DB name) G21K 1/06

Claims (1)

(57) [Claims] 1. A spectroscopic element comprising a metal-encapsulated fullerene crystal.