JPH05264477A - Analyzing method for degree of orientation of crystalline phase - Google Patents

Abstract

PURPOSE:To analyze the degree of orientation of a crystalline phase of even a thin surface layer by setting the angle of incidence of X-rays to a sample to be so small as to obtain only the diffraction line by the surface layer. CONSTITUTION:When monochromatic X-rays of good parallelism are cast to a thin film on a substrate, the X-rays are elastically scattered at the crystalline surface of the surface layer or in the base material and observed only in a peculiar direction 2theta to the crystalline phase and the crystalline surface among the incident X-rays. When the angle of incidence alpha is made large, the intensity of a diffraction circle by the crystalline surface in the base material becomes larger as compared with that of a diffraction circle by the crystalline surface in the surface layer, and consequently the diffraction circle by the crystalline surface in the surface layer is hidden. The angle of incidence alpha should accordingly be set to be small in order to obtain the diffraction circle by the crystalline surface in the surface layer. For this purpose, the X-rays are turned to X-rays of good parallelism through a single aperture collimator 11, and brought into a flat sample 13 with small angles whereby only the diffraction line by the surface layer is obtained. The X-rays are diffracted by the sample 13 and caught as a diffraction circle by a film 12. Accordingly, the degree of orientation of the crystalline phase is analyzed.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a surface layer or a thin film (hereinafter,
Both are collectively referred to as "surface layer"), and more specifically, regarding the method for analyzing the orientation of the crystal phase of the crystal phase in the surface layer obtained by plating, vapor deposition, surface modification such as ion plating, or mechanical grinding. Orientation analysis method.

[0002]

2. Description of the Related Art Generally, as a method of analyzing the orientation of a crystal phase for analyzing a crystal structure of a sample, there is a method utilizing an X-ray diffraction method, and more specifically, a Laue method using a photograph or a polar figure measurement. There is a law. Further, the Laue method includes a method called a back reflection Laue method and a method called a transmission Laue method, and the polar figure measuring method also includes a reflection method and a transmission method.

These methods will be described in order with reference to FIGS. First, the back reflection Laue method will be described. This method can also be used when the sample thickness is so large that X-rays cannot pass therethrough. Therefore, in the back reflection Laue method, as shown in FIG. 6, the cassette 12 supports both the film (installed on the sample side surface of the cassette 12) and the single-hole collimator 11, and the single-hole collimator 1
1 is attached to the center of the cassette 12. Then, with the sample 13 placed at a distance D from the film, the sample 13 on the support 14 is irradiated with X-rays through the collimator 11, and the diffracted X-rays reflected from the sample 13 are captured by the film.

Next, the transmission Laue method will be described. This method is used when the sample thickness is thin enough to allow X-rays to pass therethrough, and thick enough to detect diffraction circles. In this method, as shown in FIG. 7, a film (installed on the surface of the cassette 12 on the sample side) is arranged in the direction opposite to the X-ray source with respect to the sample 13, and X-rays are passed through the collimator 11 to support the support table. The sample 13 on 14 is irradiated. Then, the X-rays pass through the sample 13, and the diffracted X-rays thus transmitted are captured by the film.

Further, in the sample system in which the variation of the crystal plane spacing is small, when the orientation of the specific crystal plane with respect to the specific direction in the sample is desired, the polar figure measuring method is used. First, the reflection method will be described. This method is used when the sample thickness is too thick to allow X-rays to pass through, and the optical system in this method has an incident angle and a reflection angle of θ, respectively, as shown in FIG. It is an optical system of equiangular reflection. The reflection method is performed by α rotation about the A axis in the sample surface and β rotation about the sample surface normal (B axis), in other words, goes straight in the specific direction RD in the sample. By rotating the sample 13 around the A axis and the B axis in two directions, the direction of the sample 13 with respect to the incident X-ray is changed, and the intensity distribution of the diffraction line is measured. That is, when the X-ray passes through the DS slit 17 and the Schultz slit 20 and is applied to the sample 13, the X-ray is diffracted by the sample 13, passes through the RS slit 18 and the SS slit 19, and is measured by the counter 16. It

The sample is thin enough to allow X-ray transmission,
When the sample thickness is large enough to detect the diffraction circle, the transmission method is used. As shown in FIG. 9, this is α rotation about the A axis in the sample plane and β which is rotation in the sample plane.
Diffraction line (diffraction angle is 2θ) by changing the sample direction by rotation
The intensity distribution of is measured. In other words, the X-ray is the DS slit 17
When the sample 13 is irradiated through the
Is diffracted by. After the diffracted wave passes through the sample 13, RS
Counter 1 through slit 18 and SS slit 19.
Measured at 6.

When examining the degree of orientation of a crystal phase in a thin film obtained by plating, vapor deposition, surface modification such as ion plating, or mechanical grinding, the sample thickness is so thick that X-rays cannot pass through. Therefore, conventionally, the back reflection Laue method and the reflection method among the polar figure measurement methods have been used among the above methods.

[0008]

However, in the back reflection Laue method and the reflection method in the polarographic measurement method described above, since the diffraction circular intensity by the base material is generally larger than the diffraction circular intensity by the thin film, that is, the surface layer, The diffraction circle may be hidden by the diffraction circle of the base material. Further, when the surface layer was so thin that the diffraction circle could not be detected, analysis was impossible. For this reason, there has been a problem that it is usually difficult to analyze the degree of orientation of the crystal phase in the surface layer.

The present invention has been invented in view of the above problems, and by devising the optical system, the diffraction intensity by the base material is weakened and the diffraction intensity by the surface layer is enhanced, and the conventional optical system can detect the diffraction circle. It is an object of the present invention to provide a method for analyzing the degree of orientation of a crystal phase in a surface layer which can be applied to a thin surface layer which has not been present.

[0010]

In order to achieve the above-mentioned object, the crystal phase orientation analysis method according to the present invention detects a diffracted X-ray two-dimensionally by irradiating a sample with an X-ray passed through a collimator. In the method of measuring the degree of orientation of the crystal phase in the surface layer based on the diffraction circle obtained by the above, the incident angle of the X-ray to the sample is set to a low angle in the range where only the diffraction line by the surface layer is obtained, The feature is that the degree of orientation of a plurality of crystal planes or a plurality of crystal phases is simultaneously measured from the continuity of circles.

[0011]

The concept of the method according to the invention is explained by the oblique incidence Laue method, which is an application of the concept of the back reflection Laue method. The oblique incidence Laue method will be described with reference to FIGS. 1 and 2. Figure 1
2 is a schematic diagram showing the optical system of the oblique incidence Laue method, and FIG. 2 is a schematic diagram considering the spread of incident X-rays in FIG. When the thin film on the substrate is irradiated with monochromatic X-rays with good parallelism, the X-rays elastically scattered by the crystal plane in the surface layer or the base material have a direction 2θ peculiar to the crystal phase and the crystal plane with respect to the incident X-ray. Only observed. The following equation 1 is established between the 2θ and the crystal plane spacing d.

[0012]

2 dsin θ = λ where λ represents the wavelength of the characteristic X-ray generated from the tube 21.

In the measurement, the sample was exposed with the incident X-ray being tilted by a slight incident angle α, and then the sample was removed for a short period of time, and the X-ray was a straight line.
Record point A where Let R be the distance from this point A to the diffraction circle (radius of the diffraction circle), and let X on the sample from this point A.
Assuming that the distance to the line irradiation point is D, the relationship between R and D is as shown in Formula 2.

[0014]

## EQU00002 ## R = Dtan2.theta .. Further, in the Laue method, a monochromatic X having a constant wavelength is used as an incident X-ray.
Not a line but a multi-colored X that is similar to a single color with some continuous X-rays added
Since a line is used, in the diffraction by a specific surface, there are innumerable 2θs that satisfy the equation (1), the background of the film becomes high, and the diffraction circle becomes difficult to see. There is an error in reading the value.
Therefore, in order to accurately measure the R value, it is effective to make the incident X-ray monochromatic or reduce the tube voltage to reduce the contribution of continuous X-rays. Further, in a diffractive circle with a large R, the distance between the X-ray irradiation point and the diffractive circle becomes large, and the X-ray intensity on the film decreases, so that the reading of the R value becomes inaccurate. Further, as shown below, since the diameter φ of the collimator is not zero, the spread of the incident X-ray cannot be ignored in the diffraction circle having a large R. FIG. 2 shows an optical system of the oblique incidence Laue method in consideration of the spread of incident X-rays. From FIG. 2, the major axis of the X-ray irradiation point (ellipse) is φ / s.
It can be seen that it is equal to inα, and the width ΔR of the diffraction circle on the film is obtained by the following formula 3.

[0015]

## EQU00003 ## .DELTA.R = (tan2.theta./tan.alpha.-1) .phi. Due to the widening of the width of the diffraction circle, the R value has a width of .DELTA.R. Therefore, in order to accurately read the R value, it is necessary to substitute the diameter of the collimator into the formula 3 to determine the range of 2θ. For example, when the diameter of the collimator is 1 mm, it is necessary to set α <2θ <30 °. is there. Further, in order to set 2θ within this range, 2θ is calculated in the formula 1 and the expected d
After substituting the value range and, and calculating the range of the value that λ should take,
By using an X-ray tube having a characteristic X-ray wavelength within this range, the accuracy of reading the R value can be improved.

When the incident angle α is increased under the above conditions, the intensity of the diffraction circle by the crystal plane of the base material becomes larger than that by the crystal plane of the surface layer. Hidden in the diffraction circle by the crystal plane of the base material. To obtain the diffraction circle by the crystal plane in the surface layer, conversely α
Is made smaller so that the intensity of the diffraction circle by the crystal plane of the base material is smaller than the intensity of the diffraction circle by the crystal plane in the surface layer.

However, when α is made small, the X-ray irradiation point becomes a flat ellipse, so that it is difficult to obtain an accurate D value. Therefore, first, using a sample whose crystal phase in the base material is known, the incident angle α
Is increased to obtain the diffraction circle of the base material. JCPDS (Joint Committee on the crystalline phase in the base material)
Powder Diffraction Stand
d) of the crystalline phase in the base material can be obtained using the card, and θ can be obtained by substituting this d into the equation 1, while R of the base material can be read from the film, so Substitute R of the material to obtain an accurate D value. Next, α is reduced to obtain a diffraction circle by the surface layer, and R of the surface layer is measured. By substituting the values of D and R of the surface layer that have been obtained in the equation (2), θ in the surface layer is obtained. Furthermore, it is possible to obtain d by substituting this θ into the formula 1 and using the value of this d to obtain the surface index of the surface layer using a JCPDS card.

When α is increased, not only the diffraction circle due to the crystal plane in the surface layer but also the diffraction circle due to the base material appears. Therefore, among the diffraction circles on the film, it depends on the crystal plane of the base material and the crystal plane of the surface layer. The distinction from the object can be made by changing the incident angle α. If the base material is not known, an optical system capable of accurately defining D is required.

[0019]

EXAMPLES Examples of the crystal phase orientation degree analysis method according to the present invention will be described below with reference to the drawings. The components having the same functions as those of the conventional example are designated by the same reference numerals. FIG. 1 is a diagram schematically showing an optical system of a crystal phase orientation analysis method in Examples. In this embodiment, the concept of the back reflection Laue method is applied and the analysis is performed using the oblique incidence Laue method.

The monochromatic X-rays or the near-monochromatic X-rays generated from the X-ray tube 21 pass through the single-hole collimator 11 and become parallel X-rays, which are incident on the flat plate sample 13 at a grazing angle. The X-ray incident at this time is diffracted by the sample 13, becomes a diffraction circle, is captured by the film 12, and the degree of orientation is analyzed.

As sample 13, an alloyed galvanized steel sheet having an average iron content in the plating layer (alloying degree) of 8.5% and a thickness of the plating layer (area weight) of 56.0 g / m ^{2 on} one side was used. I was there. The measurement conditions are as shown in Table 1 below.

[0022]

[Table 1]

The (633) plane and δ _{1 of the} alloy phase Γ in the plating layer appearing near the diffraction circle of the base material α-Fe (211).
The Mo tube (λ = 0.711Å) was used as the tube for the measurement under the condition that α <2θ <30 ° when the degree of orientation of the (554) plane of the phase was set to 1 mm for the collimator. ..

The obtained diffraction circles are as shown in FIG. 3, and the relation between R, 2θ, d and the surface index of each diffraction circle obtained based on the data of FIG. 3 is shown in Table 2. Show.

[0025]

[Table 2]

From FIG. 3, a strong and broad diffraction circle 28 can be seen, and broad diffraction circles 27 and 26, which are slightly weaker than the diffraction circle 28, can be seen inside thereof. Inside is a broader diffraction circle 25, which is slightly weaker than the diffraction circles 27 and 26.
However, on the inner side, the diffraction circles 24, 2 weaker than the diffraction circle 25
3, 22, 21 can be seen in order. This diffraction circle 21-
Since all 28 are semi-circles with uniform intensity on the diffraction circumference, they can be said to be non-oriented around the X-ray incidence axis. For example,
Δ ₁ (554) plane of diffraction circle 26 and Γ (63
3) Taking the plane as an example, similar results were seen when α was constant and the orientation of the sample with respect to the incident X-ray was changed, or when α was changed to 5 degrees and 15 degrees. , Δ ₁ phase and Γ phase are both non-oriented in the plating layer.

The diffraction circle 22 has a δ ₁ (154) plane and a Γ
The diffraction circles of the ₁ (733) plane are overlapped, and the diffraction circle 23 has the ζ (221) plane, the (6 bar 02) plane, and the δ ₁ (33
The diffraction circles of the (0) plane are overlapped.

An accurate D value was found to be 58 mm by the method described in the section of action. Next, by substituting D and the R value of the surface layer into the equation (2), θ by the surface layer is obtained. further,
By substituting this θ into the formula 1, d is obtained, and J is calculated from the value of d.
Table 2 shows a surface index obtained by a CPDS card and summarized for each diffraction circle.

Next, as a comparative example, δ ₁
The results of orientation degree analysis of the (554) plane and the Γ (633) plane will be described.

FIG. 4 is a diagram of a diffraction circle obtained by the back reflection Laue method. The solid line part is the observed diffraction circle, and the dotted line part is the unobserved diffraction circle. The measurement conditions are as shown in Table 3.

[0031]

[Table 3]

In the back reflection Laue method, 2θ is about 120.
Since it is necessary to set it to be at least °, the δ ₁ (554) plane and Γ (6
As the tube, a Cr tube (λ = 2.291Å) was used so that the diffraction circles 33, 32 of the 33) plane could be observed within this range.
However, as can be seen from FIG. 4, the δ ₁ (554) plane and the Γ (6
The diffraction circles 33 and 32 on the (33) plane were not seen. Since the incident angle is as large as 90 degrees, the X-ray path length passing through the plating layer is as small as 12 to 14 μm reciprocating, and therefore,
This is because the diffraction intensity of the alloy phase becomes weak. The D value was 20 mm.

Further, FIG. 5 is a diagram showing a polar figure obtained by a polar figure measuring method by reflection for the same sample. The measurement conditions are shown in Table 4 below.

[0034]

[Table 4]

It can be seen that it is difficult to determine the presence / absence of orientation because the diffraction intensity of the Γ (633) plane is weak. This is because the diffraction intensity of the alloy phase is reduced due to the large incident angle, or the diffraction intensity is reduced due to a slight variation in the crystal plane spacing between the sample preparation history peculiar to plating and slag. In the polarographic measuring method for measuring the intensity at a constant diffraction angle, the influence of the variation of the crystal plane spacing is large.

As described above, according to the conventional back reflection Laue method, the diffraction intensity of the crystal phase in the surface layer is so weak that it cannot be detected on the film, and therefore it is difficult to analyze the degree of orientation of the surface layer.
In the conventional polar figure measurement method, when the diffraction intensity of the crystal phase in the surface layer is weak or the crystal plane spacing fluctuates, it is difficult to determine the presence or absence of the orientation from the polar figure, so it is difficult to analyze the orientation degree of the surface layer. there were. However, in the above examples, by making the incident angle small, it is possible to increase the diffraction intensity of the crystal phase in the surface layer. The orientation of the surface layer can be analyzed.

[0037]

As described above in detail, in the crystal phase orientation analysis method according to the present invention, X-rays are passed through the sample with a collimator.
In the method of measuring the degree of orientation of a crystal phase in a sample based on a diffraction circle obtained by irradiating the sample with a two-dimensional detection of a diffracted X-ray, the incident angle of the X-ray with respect to the sample is determined by the surface layer. By making the angle low enough to obtain only the diffraction line by, the diffraction intensity from the base material is weakened, and the diffraction intensity from the surface layer is strengthened. Even so, it became possible to analyze the degree of orientation.

[Brief description of drawings]

FIG. 1 is a schematic diagram schematically showing an optical system of an oblique incidence Laue method used in an example of a crystal phase orientation degree analyzing method according to the present invention.

FIG. 2 is a schematic diagram of an optical system that considers the spread of incident X-rays in FIG.

FIG. 3 is a schematic diagram of a photograph obtained by measurement by an oblique incidence Laue method used in an example of a crystal phase orientation degree analysis method according to the present invention.

FIG. 4 is a schematic diagram of a photograph obtained by measuring the degree of orientation of the alloy phase of an alloyed galvanized steel sheet by the back reflection Laue method which is a conventional method of analyzing the degree of orientation of a crystal phase.

FIG. 5 is a polar figure obtained by measuring the degree of orientation of an alloy phase of an alloyed galvanized steel sheet by a reflection method in a polar figure measuring method which is a conventional crystal phase orientation degree analysis method.

FIG. 6 is a schematic diagram schematically showing an optical system of a back reflection Laue method which is a conventional crystal phase orientation analysis method.

FIG. 7 is a schematic diagram schematically showing an optical system of a transmission Laue method, which is a conventional crystal phase orientation analysis method.

FIG. 8 is a schematic diagram schematically showing an optical system of a reflection method in a polar figure measuring method which is a conventional crystal phase orientation degree analyzing method.

FIG. 9 is a schematic view schematically showing an optical system of a transmission method in a polar figure measuring method which is a conventional crystal phase orientation degree analyzing method.

[Explanation of symbols]

 11 Single hole collimator 13 Sample

Claims (1)

[Claims] 1. The orientation degree of a crystal phase in a surface layer or a thin film is measured based on a diffraction circle obtained by irradiating a sample with X-rays passed through a collimator and detecting the diffracted X-rays two-dimensionally. In the method, the angle of incidence of X-rays on the sample is set to a low angle within a range where only the diffraction line of the surface layer or thin film of the sample is obtained, and the degree of orientation of a plurality of crystal planes or a plurality of crystal phases is determined from the continuity of diffraction circles. A method for analyzing the degree of orientation of a crystal phase, which is characterized by simultaneous measurement.