JP3504539B2 - X-ray diffractometer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an aperture angle of a light receiving portion in an X-ray diffractometer.

[0002]

2. Description of the Related Art Conventional X-ray diffractometers have been designed with the structural evaluation of bulk materials, simple multilayer thin films and epi films in mind. For this reason, attention has been paid only to the detection sensitivity and the like of the design of the X-ray receiver, and the problem of how many opening angles the X-ray receiver desirably has has been neglected. Substantially no problem occurred in the evaluation of the conventional bulk material, simple thin film, and epi film peak as long as the 2θ opening angle is about 2 degrees. In the past, there was almost no recognition of the necessity or necessity of measuring with a wide opening angle. Rather, in order to improve the measurement sensitivity by cutting unnecessary scattered waves, attention has been paid only to the measurement in which a slit or the like is installed in front of the X-ray receiver, that is, to narrow the opening angle. This tendency is becoming more remarkable as the resolution of the X-ray diffractometer has been increased in recent years.

Further, in recent years, a reciprocal lattice mapping measurement technique has been often used as a new X-ray diffraction measurement technique. The reciprocal lattice mapping measurement can be performed by inserting an extremely high spatial resolution filter called an analyzer crystal in place of the slit in front of the X-ray receiver. The insertion of the analyzer crystal substantially corresponds to extremely narrowing the 2θ opening angle of the light receiving system. This dramatically improves the measurement resolution in the reciprocal lattice space and enables mapping measurement.

In order to perform such a mapping measurement, it is necessary to adjust the measurement condition around the peak to be measured and select it. Performing this work from the beginning by using an X-ray receiving system in which an analyzer crystal is inserted is a very laborious and difficult work. Therefore, generally, the adjustment is first performed in a state in which the analyzer crystal is not inserted, that is, only the X-ray light receiver or the light receiving system in which the X-ray light receiver and the slit are combined. After that, an analyzer crystal is inserted to configure a desired X-ray receiving system, and fine adjustment is performed, whereby it becomes possible to select measurement conditions around the peak to be measured.
Furthermore, in order to make this work more efficient, the first for coarse adjustment
The first X-ray receiving system in which the X-ray receiving device and the slit are combined, and the second X-ray receiving system in which the second X-ray receiving device for fine adjustment and measurement and the analyzer crystal are combined are separately provided. It is usually practiced to construct an integrated light receiving system having two sub light receiving systems by preparing the light receiving system of No. 1 and mounting them on the same table. (For example, Phillips (Ph
X-ray diffractometer X'pert MRD), Inc.) By simply shifting the position 2θ of the integrated light receiving system by a certain amount, it is possible to easily change which of the two sub X-ray light receiving systems is to be used. You can Therefore, the above-mentioned adjustment work is extremely easy to perform. In such an integrated light receiving system, the opening angle of the first X-ray light receiving system is designed to be narrower than in the usual case. Specifically, it is designed to have a 2θ opening angle of about 1 to 2 degrees. The reason for this is that there has not been much demand for measurement with a large opening angle.

[0005]

The conventional design of the aperture angle of the X-ray receiving system described in the section [Prior Art] above was considered to have no problem in the past, but From a point of view, it has become clear that there are problems. First of all, the diversification of measurement samples is the origin of the problem. That is,
Not only conventional bulk materials and simple thin films, evaluation of epi film peaks, but also various structures such as hetero epi films (having large lattice mismatch) and (strain) superlattice structure combining various material systems The sample that has become a target for X-ray diffraction evaluation. The X-ray diffraction peaks from these samples are diverse and distributed over a wide range of the reciprocal lattice space. It is not easy to search such a wide range under the above-mentioned narrow opening angle condition by the method as described in the above [Prior Art] and find out the condition necessary for measurement for each sample. Furthermore, it is inefficient to evaluate all of a series of X-ray diffraction peaks distributed over such a wide range only by the conventional reciprocal lattice mapping measurement, because the measurement time increases significantly. Therefore, the problem that a more efficient method is required has become apparent.

In recent years, the present inventors have proposed a method that is effective in efficiently evaluating a sample having such a complicated structure by X-ray diffraction, and reported its effectiveness. (K. Nakashima and H.S.
ugiura, Jpn. J. Appl. Phys. Pa
rt 1,36,5351 (1997) and K. Na
Kashima and H.M. Sugiura, J .; A
ppl. Crystallogr. , 30, 1002
(1997, etc.) In these methods, the index (hkl) is changed, various X-ray profiles are measured, and the obtained data is analyzed. At this time, particularly in the index (hkl) measurement, it is extremely important to determine how many conditions the aperture angle of the X-ray receiving system should measure. In this case, since the scan direction in the reciprocal lattice space and the direction in which the diffraction spot exists generally do not match, it is required to measure with a wide aperture angle of the X-ray receiving system. However, these points are not taken into consideration at all in the conventional aperture angle design of the X-ray receiving system. In addition, the problem that the aperture angle does not satisfy the requirements even in actual measuring devices has become clear during these research processes. Furthermore, there has been no clear guideline on how to design the opening angle from these viewpoints.

The present invention has been made in view of the above circumstances, and makes it possible to more easily perform general index (hkl) reflection measurement by making it possible to set the aperture angle of the X-ray receiving system to be wider than 3 degrees. An index (hkl) for easy analysis of various samples with complex structures.
Various analysis methods using dependency can be applied more easily X
An object is to provide a line diffraction device.

[0008]

In order to achieve the above object, an X-ray diffractometer according to the present invention comprises an X-ray receiver in an X-ray diffractometer.
A slit is inserted in front of the optical device and the optical receiver.
By holding an auxiliary jig for lit insertion,
Integrated such that it is possible to limit the opening angle of the vessel
X-ray receiving system, which measures without the slit
If the aperture angle of the receiver is 2θ
Integrated X-ray receiver with a wide 2θ opening angle of more than 1 degree
It is characterized by having an optical system.

[0009]

Further, the X-ray diffractometer of the present invention comprises, in the X-ray diffractometer, a first X-ray photoreceiver and a first X-ray photodetector and an auxiliary jig for placing a slit in front of the first photoreceiver. 2 of the X-ray receiving system, which is composed of a line receiving system, a second X-ray receiving unit, and an analyzer crystal in which crystals are arranged in front of the second receiving unit so as to satisfy a Bragg condition. Two x
The line light receiving system is further integrated to form one large light receiving system, and the position 2θ of the large light receiving system is shifted by a certain amount so that either of the two X-ray light receiving systems can be selected and used. An integrated X-ray receiving system,
The first X-ray receiving system is provided with an integrated X-ray receiving system having a wide 2θ opening angle of 3 ° or more in terms of the 2θ expected angle when the measurement is performed by removing the slit. It is characterized by that.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

It is indispensable to have a structure of a light-receiving system that allows easy measurement under a wide opening angle condition of the X-ray light-receiving system. At this time, it is necessary to perform the measurement under the condition that the opening angle is narrow, which has been conventionally considered, so that it is necessary to be able to freely select which opening angle condition is used for the measurement. The present invention considers the following as means for satisfying these requirements.

(1) When the X-ray receiver is viewed from the position of the sample to be measured, the opening angle of the receiver main body has a wide 2θ opening angle of 3 ° or more in terms of the 2θ prospective angle. Set the aperture area and the distance from the sample to the receiver body. This will be specifically described below. FIG. 1 shows a schematic view of the structure of the X-ray photoreceiver in the X-ray diffraction apparatus according to the present invention and the positional relationship with the surroundings, and the 2θ opening angle. As shown in FIG. 1, the angle 2Δθ formed by the opening of the X-ray receiver (light receiving system) 12 measured around the position of the sample 11 is 2θ.
The opening angle. Therefore, under the above conditions, 2Δθ is 3
It means to be more than once. Now, assuming that the radius of the opening of the X-ray receiver 12 is r and the distance from the sample 11 to the X-ray receiver 12 is R, the relational expression of Δθ≈r / R approximately holds. From this, this condition can be realized by taking the ratio of r and R so as to satisfy the above condition. Thirteen
Is an X-ray source.

(2) FIG. 2 is a schematic view of a 2θ opening angle in an X-ray receiving system in which an X-ray receiving device according to the present invention and an auxiliary jig for slit insertion are integrated. In the case of an X-ray receiving system provided with a slit insertion auxiliary jig 15 in which the slit 14 is placed in front of the X-ray receiver 12, in addition to the condition relating to the structure of the receiver main body described in (1) above, the slit 14 is installed. As a condition in the case of pulling out and measuring at the widest opening angle, a wide 2θ opening angle of 3 ° or more is set as a 2θ prospective angle. This corresponds to providing an X-ray receiving system in a structure in which the slit insertion auxiliary jig 15 for placing the slit 14 does not limit the opening angle. That is, as shown in FIG. 2, instead of the opening angle of the X-ray receiver 12 of FIG. 1, the opening angle limited by the slit insertion auxiliary jig 15 is taken and considered in the same manner as in the case of (1). Good. This guarantees that measurement can be performed under the widest opening angle condition of 3 degrees or more, and by changing the width of the slit 14 to be inserted, it is also possible to set and measure the arbitrary opening angle of 3 degrees or less. . That is, it can be seen that the above requirements are satisfied.

(3) In the case of the integrated X-ray light receiving system having two sub-light receiving systems for reciprocal lattice mapping measurement, which was mentioned in the section [Prior Art] above, described in (2). The above structure may be adopted as the structure of the first X-ray receiving system for rough adjustment. Further, the first and second X-ray receiving systems are arranged so that the second X-ray receiving system (such as an analyzer crystal in which multiple crystals are arranged so as to satisfy the Bragg condition) does not obstruct the opening angle of the first X-ray receiving system. A structure that requires a large amount of shift for selecting the X-ray receiving system is also required as a setting condition for integration.

In the above (1) to (3), the condition of the opening angle of 3 degrees or more is a value that has been clarified for the first time as a result of the study on which the present invention is based.

The present invention solves the problems relating to a wide aperture angle condition, which has not been considered in the past, by improving the structure of the aperture angle of the X-ray receiving system portion in the X-ray diffractometer. The present invention enables measurement under a wide aperture angle condition that cannot be measured by the conventional light receiving system. Due to this improvement, measurement using various indices (hkl), which have been increasingly required in recent years with the diversification and complexity of samples, can be performed more easily. In addition, an integrated X with two sub-receiver systems for reciprocal lattice mapping measurements
By applying the present invention to a line receiving system, reciprocal lattice mapping measurement can be performed significantly more easily than in the past.

Next, a specific example of the present invention will be described.

A specific example of the first sub-light-receiving system in the integrated X-ray light-receiving system having two sub-light-receiving systems for reciprocal lattice mapping measurement is shown below. InGaAsP for X-ray diffraction measurement
System strained superlattice samples were used.

First, for comparison, the result of (400) reflection measurement is shown in FIG. 1 / 4m in front of the receiver during this measurement
The measurement was performed by inserting an m-width slit. In this case, the narrow opening angle condition is 0.5 ° or less in terms of the 2θ expected angle. In the case of (400) reflection measurement, since there is no influence of the aperture angle, a large number of peaks up to satellite peaks of high order are clearly observed despite the narrow aperture angle condition.

However, in general index (hkl) reflection measurement, the influence of the aperture angle appears remarkably. Here (42
2) An example of reflection measurement is shown. First, FIG. 4 shows an X-ray diffraction measurement result obtained by using a conventional (first sub) light-receiving system having a structure with a relatively narrow aperture angle and measuring conditions under which a slit is removed.
It shows in (a). Here, the measurement was performed by the asymmetric reflection arrangement. The opening angle of the light receiving system in this measurement is 1 degree in terms of the 2θ expected angle. In principle, a satellite peak profile similar to the (400) reflection measurement profile should be observed in the (422) reflection measurement profile. Therefore, when combined with the results of FIG. 3, many satellite peaks should be observed up to high order in FIG. 4 (a). However, in FIG. 4A, only some low-order satellite peaks near the substrate peak are observed, and high-order peaks are not observed at all. It is considered that this is because the aperture angle is narrow and the higher-order peaks are diffracted to a position where they do not enter the X-ray receiving system. In order to further confirm this, a similar measurement was performed by inserting a slit having a width of 1/4 mm in front of the light receiver. Figure 4 shows the results obtained.
It shows in (b). In this case, the estimated angle of 2θ is 0.5
The opening angle condition is smaller than that, which is narrower than that in FIG. It can be seen that the number of observed satellite peaks is further reduced in FIG. 4B as compared with FIG. 4A. From this result, it was confirmed that the reason why no higher-order peak was observed was that the aperture angle of the conventional X-ray receiving system was too narrow. From these results,
It was found that the conventional light receiving system having a structure with a relatively narrow aperture angle causes a problem in measurement.

On the other hand, if the aperture angle is widened according to the present invention, such higher-order peaks also come into the aperture of the X-ray receiving system, so that they can be observed. Figure 5 (first vice)
The result of the (422) reflection measurement of the same sample measured by the apparatus using the light receiving system (condition without slit) in which the aperture angle of the light receiving system is set to 3 ° and the angle is set to 3 ° is shown. A symmetrical reflection arrangement was used here. In FIG. 5, it can be seen that a series of satellite peaks similar to those in FIG. 1 are clearly observed up to higher orders. That is, due to the effect of widening the opening angle, the (422) reflection measurement can be performed without any problem.
It turns out that the problem in is solved. Also, in the case of a general index (hkl) reflection measurement, it can be experimentally confirmed in the same manner that the measurement can be performed without any problem if the aperture angle of the light receiving system is set to 3 ° or more with an estimated angle of 2θ.

From the above specific examples, it can be seen that the present invention allows the general index (hkl) reflection measurement to be performed more easily.

Further, the above effect is reversed when the present invention is applied to the first sub-light-receiving system in the integrated X-ray light-receiving system having two sub-light-receiving systems for reciprocal lattice mapping measurement. It also makes a significant difference on the grid mapping measurements. This will be explained below. In the reciprocal lattice mapping measurement, an outline of the diffraction pattern is usually measured in advance by θ-2θ mode scanning using the first sub-light-receiving system, and which part is actually reciprocal lattice mapped based on the obtained diffraction pattern. Decide The reciprocal lattice mapping measurement is usually performed using a biaxial scan that is a combination of the θ-2θ mode scan and the ω mode scan, and the measurement range is specified by specifying the range for each θ-2θ and ω mode. . Further, in the actual reciprocal lattice mapping measurement, switching to the second sub-light receiving system is performed. In order to perform this switching work efficiently, a structure in which two sub-light receiving systems are integrated is essential. A specific example of the outline of the diffraction pattern obtained by using the first sub-light receiving system in such an integrated light receiving system corresponds to FIGS. 4 and 5 described above. That is, FIG. 4 shows θ-2 when the first sub-light receiving system has a conventional narrow aperture angle.
FIG. 5 is a diffraction pattern by θ mode measurement, and FIG. 5 shows θ-2θ when the opening angle according to the present invention is widened to 3 degrees or more.
Corresponds to the diffraction pattern by mode measurement.

There is a significant difference between the two cases in setting the reciprocal lattice mapping measurement range from these diffraction patterns. In the case of FIG. 4 of the related art, only a few peaks appear in the range of θ of about ± 1 degree around the peak of the substrate. On the basis of this result, if the θ-2θ mode scan range for reciprocal lattice mapping measurement is selected to be ± 1 degree around the substrate peak, it is impossible to actually observe peaks outside the range. Become. In FIG. 4, when it is desired to measure the area outside the observation by reciprocal lattice mapping, it is necessary to set a scan range that is much wider than about ± 1 degree. However, it is virtually impossible to set the measurement conditions from the diffraction pattern data of FIG. In such a case, the measurement range is usually widened to some extent and the measurement is repeated by trial and error. However, since reciprocal lattice mapping is a time-consuming measurement method, setting a large scan range unnecessarily leads to a significant increase in measurement time, which is inefficient and should be avoided in practice. From the above, it can be concluded that the conventional first sub-light receiving system having a narrow aperture angle has a problem in setting the measurement range of reciprocal lattice mapping.

In FIG. 5, which is a specific example of the present invention, however, all diffraction peaks can be observed due to the effect of widening the aperture angle. That is, it can be considered that there are no peaks other than the peaks observed in FIG. Due to this effect, in setting the θ-2θ mode scan range at the time of reciprocal lattice mapping measurement, it is important to be able to determine efficiently from only the data in FIG. For example, in FIG.
From the results, it is sufficient to set the θ-2θ mode scan range at the time of the reciprocal lattice mapping measurement to about ± 2 degrees around the substrate peak in order to be able to observe all the peaks. It can be seen that a meaningful peak can never be obtained even if the range is widened. Also, when it is desired to measure the reciprocal lattice mapping only around a specific peak located away from the substrate peak, it is easy to determine how far away from the substrate peak the scanning range should be based on FIG. Can be set to. From these examples, by preliminarily storing the measurement data of FIG. 5, it is possible to efficiently set the θ-2θ mode scan range at the time of reciprocal lattice mapping measurement. That is, it is possible to remarkably reduce the labor for repeating the determination by trial and error as described in the case of FIG. 4 of the conventional method. Further, it is also an important effect obtained by the present invention that the measurement time of the reciprocal lattice mapping measurement can be remarkably shortened due to the fact that the scan range can be minimized. FIG. 6 shows an example of the (422) reflection reciprocal lattice mapping measurement measured by the above procedure in this example. It can be seen that the scan range is efficiently selected for the obtained peak.

[0027]

When a general index (hkl) reflection measurement is performed using an X-ray diffractometer having a conventional X-ray receiving system with a relatively narrow aperture angle, a peak (higher-order satellite) apart from the substrate peak is measured. There was a problem that observations (such as peaks) did not take place. According to the present invention, the opening angle of the X-ray receiving system is set to 3
By allowing the setting to be wider than that, it has become possible to solve this problem and perform general index (hkl) reflection measurement more easily. Due to the effect of the present invention, it becomes possible to more easily set the conditions for performing the method of performing the measurement such as the reciprocal lattice mapping measurement with the aperture angle extremely narrowed. In addition, it is expected that various analysis methods using exponential (hkl) dependence for easy analysis can be more easily applied to various samples having a complicated structure. .

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a structure of an X-ray photoreceiver in an X-ray diffraction device according to the present invention and a positional relationship between the X-ray photoreceiver and its surroundings, and a 2θ opening angle.

FIG. 2 is a schematic diagram showing an example of a 2θ opening angle in a light receiving system in which an X-ray light receiver according to the present invention and a slit insertion auxiliary jig are integrated.

FIG. 3 shows InGaAsP / In used in an embodiment of the present invention.
FIG. 6 is a characteristic diagram showing a (400) X-ray diffraction profile of a GaAsP strained superlattice sample. 1 in front of the receiver when measuring
The measurement was performed by inserting a slit having a width of / 4 mm. This condition is a narrow opening angle condition with an estimated 2θ angle of 0.5 degrees or less.

FIG. 4 is the InGaAsP / InGaAsP used in FIG.
(422) reflection θ-2 of a strained superlattice sample measured by a conventional method
It is a characteristic view which shows a (theta) scan measurement result. (A) In the case of measurement without a slit in front of the first sub-light receiver. The opening angle of the first sub-light-receiving system in this measurement is 1 degree, which is a 2θ expected angle. (B) A case in which a slit having a width of 1/4 mm is inserted in front of the first sub-light receiver for measurement. In this case, the angle of 2θ is 0.5 ° or less, which is a narrower opening angle condition than that of (a).

5 is a specific example of the present invention, which is measured by an apparatus using a first sub-light receiving system (without slit) in which an opening angle is set to 2θ prospective angle and set to 3 degrees (422 of the sample of FIG. )
It is a characteristic view which shows the result of reflection (theta) -2 (theta) scan measurement.
Measured with symmetrical reflection arrangement.

FIG. 6 is a characteristic diagram showing an example of a (422) reflection reciprocal grating mapping measurement according to a specific example of the present invention.

[Explanation of symbols]

11 samples 12 X-ray receiver 13 X-ray source 14 slits 15 Auxiliary jig for slit insertion

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 23/00-23/227 G21K 1/00-1/06

Claims (2)

(57) [Claims] 1. A in the X-ray diffraction apparatus by slits placed in front of the X-ray light receiver and the light receiving unit has combined slit insertion <br/> auxiliary Sukeji instrument is inserted, the light receiving unit a integrated X-ray light receiving system such that it is possible to limit the opening angle of, the light receiving unit opening angle when measuring except the slit, at least three times in the 2θ prospective angle An X-ray diffraction apparatus comprising an integrated X-ray receiving system having a wide 2θ opening angle. 2. An X-ray diffractometer, comprising: a first X-ray receiving system comprising a first X-ray receiving device and an auxiliary jig for placing a slit in front of the first light receiving device; Multiple crystals in front of the X-ray receiver and the second receiver Bragg
The two X-ray receiving systems of the second X-ray receiving system composed of analyzer crystals arranged so as to satisfy the conditions are further integrated to form one large receiving system, and the position 2 of the large receiving system is set.
An integrated X-ray receiving system in which one of the two X-ray receiving systems can be selected and used by shifting θ by a certain amount, and the slit is provided in the first X-ray receiving system. When the measurement is performed excluding, the aperture angle of the receiver is
An X-ray diffraction device comprising an integrated X-ray receiving system having a wide 2θ opening angle of 3 ° or more in terms of a 2θ prospective angle.