JP2968996B2 - X-ray focusing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to X which is preferably used for evaluating the crystallinity of a thin film and the like.
The present invention relates to a line condensing device.

[Prior Art] Today, devices provided with a thin film single crystal layer (including epitaxial growth) on a substrate are increasing dramatically. Also, single crystallization by controlling the orientation of a thin film layer on a substrate, laser annealing, and the like has been active. Heteroepitaxy technology for single crystal thin films by MBE or MOCVD has also been developed. Therefore, it is important to evaluate the crystallinity of thin films formed on these substrates.

On the other hand, a bond method is used for precise measurement of the lattice constant of a single crystal. The bond method is a measurement in which a single crystal sample is moved between symmetric arrangements with respect to one incident X-ray beam, and a precise lattice constant is determined from the angle difference between the arrangements at which the diffraction intensity is maximized. Is the law. It is known that X-ray diffraction measurement of a single crystal is performed by a four-axis automatic diffractometer, a precession camera, a Weissenberg camera, or the like. All of the above single crystal measurement methods are performed using one incident X-ray beam.

[Problems to be solved by the invention]

However, X-ray diffraction of a single crystal layer on a substrate cannot measure X-rays diffracted toward the substrate, and is limited to measurement of only the space on the single crystal layer side. Therefore, in the X-ray diffraction of a single crystal on a substrate, the surface of the single crystal layer to be measured needs to be positioned at the center of rotation, but the method using a single incident X-ray beam conventionally used is not practical. Was difficult.

An object of the present invention is to provide an X-ray condensing apparatus capable of realizing simultaneous measurement of X-ray diffraction at two wavelengths, which has been impossible in the related art, in view of the situation of the related art. I do.

[Means for solving the problem]

To achieve the above object, according to the present invention, one point light source for generating X-rays, two X-ray extraction windows movably provided around the point light source, and each X-ray extraction window And two crystal monochromators for Bragg-reflecting each of the emitted X-ray luminous fluxes to form an image at one point, wherein one of the crystal monochromators is movable on an arc having both ends of a point light source and a focal point, and An X-ray condensing apparatus is provided, wherein the other crystal monochromator has a point light source and a focal point at both ends and is movable on an arc that is antisymmetric with the arc.

[Action]

In the present invention, since the two crystal monochromators are arranged in a specific manner, the X-ray luminous flux emitted from one of the X-ray extraction windows is Bragg-reflected by the corresponding crystal monochromator, and becomes a desired point. An X-ray beam emitted from the other X-ray extraction window, which forms an image, is also Bragg-reflected by the corresponding crystal monochromator and forms an image at the above point. Therefore, the variable crossover angle of the same wavelength 2
One X-ray beam can always be focused on one point.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to examples.

FIG. 1 is a conceptual diagram of a two-beam condensing device according to the present invention. Slits, which are two X-ray extraction windows provided movably on the circumference, around a point light source F that generates X-rays
S ₁ and S ₂ are provided, and the X-ray luminous flux emitted from the slits S ₁ and S ₂ is respectively converted by crystal monochromators M ₁ and M ₂ .
It is reflected by Bragg and passes through slits S ′ ₁ and S ′ ₂ ,
An image is formed at a point P. Monochromator M ₁ ,
For example, a Si single crystal (111) plane can be used for M _2, but is not limited thereto. The monochromators M ₁ and M ₂ can move on a predetermined locus, which will be described in detail with reference to FIG.

As shown in FIG. 2, X of the monochromator M is placed on an arc (a part of the circle 0) having both ends of the point light source F and the focal point (imaging point) P.
Monochromator M such that M ₀ points exposed to linear light beam is located
Is arranged. The circumferential angle ∠PM ₀ F is π−2θ, and the same value is maintained as long as M ₀ moves on this arc. Therefore, the angle of the monochromator M with respect to the incident X-ray FM ₀ ∠M′M ₀ F
(M ′ and M ″ are both end points of the monochromator M) are set to θ, the X-ray luminous flux satisfying the Bragg condition 2dsin = λ (d: constant of the monochromator, λ: wavelength satisfying the Bragg condition) is obtained. It is emitted in the direction of P than M ₀ point of the monochromator M. Although this is equivalent to a monochromator M ₁ of FIG. 1, a monochromator M ₂ of FIG. 1 is also a similar anti-symmetric arrangement satisfies Bragg condition X-ray beam is emitted from the monochromator M ₂ in the direction of P by. thus first
According to the apparatus shown in the figure, two X-ray beams always converge on point P.

Also, by changing the length of the radius M ₀ O of the circle 0 in the above device, the magnitude of the circumferential angle ∠PM ₀ F changes,
It is also possible to continuously change the wavelength satisfying the Bragg condition. If this is used, it was impossible 2
Simultaneous measurement of X-ray diffraction at wavelength can be realized.

〔The invention's effect〕

According to the present invention, because of the above-described configuration, it is possible to provide an apparatus that condenses two X-ray luminous fluxes having the same wavelength and a variable crossing angle on one point P. In addition, the arrangement of the surface of the single crystal layer at the point P can be accurately performed by measuring the symmetric reflection positions of the respective light beams.

Further, in the present light concentrator, X-ray diffraction can be measured by continuously changing the crossing angle of the X-ray light beam while the single crystal is fixed at the point P.

Further, by changing the radius of the moving circle of the monochromator or changing the constant d of the monochromator, it is also possible to make a condensing system that crosses two X-ray beams having different wavelengths at one point. Of course, in this case, the light source needs to emit X-rays of these wavelengths (continuous X-rays or characteristic X-rays).

Furthermore, a light-condensing system for two X-ray beams having different wavelengths can be used for measurement of anomalous dispersion, and has an advantage that two measurements can be reduced to one.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a two-beam condensing device according to the present invention, and FIG. 2 is an explanatory diagram of a moving trajectory of a monochromator used in the present invention. F ...... X-ray point source _{S 1, S 2, S '} 1, S' 2 ...... slits M _1, M ₂ ...... crystal monochromator P ...... focal

Claims (1)

(57) [Claims] 1. A point light source for generating X-rays, two X-ray extraction windows movably provided around the point light source, and an X-ray beam emitted from each X-ray extraction window. Two crystal monochromators for Bragg reflection to form an image at one point, one crystal monochromator being movable on an arc having both ends of a point light source and a focal point, and the other crystal monochromator being a point monochromator. An X-ray focusing apparatus comprising a light source and a focal point at both ends and movable on an arc that is antisymmetric with respect to the arc.