JPS61153552A - Automatic x-ray diffraction device - Google Patents

Abstract

PURPOSE:To make possible automatic adjustment by applying a DC voltage between two electrodes on the diagonal lines of two square semiconductor plates disposed in a measuring sample position and X-ray detector position to form a Wheatstone bridge and using the current flowing between the electrodes on the other diagonal lines as a control signal for a driving device. CONSTITUTION:The square semiconductor 22 is attached, perpendicularly to an X-ray beam, to a supporting part 13 of a head of a goniometer 11. The X-ray beam is irradiated to the plate 22 and a DC voltage 27 is impressed to lead wires 23, 25. A sample stage 17 is moved in directions x, z by the driving device 18 so as to minimize the current flowing in the lead wires 24, 26. The X-ray beam is thereby positioned to the center of the plate 22 and thereafter the plate 22 is removed and a sample crystal is attached to the same position. The semiconductor plate 28 is attached to a supporting part 20 of a detector stage 19 and is irradiated with the X-ray beam emitted from the sample. The stage 19 is moved in the directions x', z' so as to minimize the current flowing in the lead wires 30, 32.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an X-ray diffraction apparatus that eliminates manual X-ray beam adjustment.

[Prior art and its problems]

X-ray diffractometers are very important as a means of crystal evaluation. For example, in evaluating various crystals used in the semiconductor industry, their lattice constants, lattice defect distributions, etc. are measured using X-ray rocking curves and X-ray topography.

When handling an X-ray device, it is extremely important to make the X-ray beam accurately enter the sample at an intended diffraction angle, and to accurately guide the X-rays emitted from the sample to a detector or dry plate. Traditionally, this adjustment has been done manually based on the operator's experience.As is well known, exposure to X-rays has extremely harmful effects on health, and cumulative exposure over a long period of time can even be life-threatening. . For this reason, workers always pay close attention to adjusting the equipment, but scattering from unintended directions 1
Exposure due to reflection is unavoidable, and there is a particular danger from the fact that X-rays are not visible.

In order to avoid such a risk, there is a system in which a large number of detectors capable of detecting minute positional changes are arranged side by side to facilitate position adjustment, but there is a problem that the system itself is expensive.

[Purpose of the invention]

An object of the present invention is to eliminate such conventional drawbacks and provide an X-ray diffraction apparatus that can be automatically adjusted.

[Structure of the invention]

The automatic X-ray diffraction apparatus of the present invention includes an X-ray source, a goniometer that supports a measurement sample that is irradiated with X-rays emitted from the X-ray source, and means for detecting the X-rays that have passed through the measurement sample.
Ohmic electrodes are provided at four corners, and square-shaped first and second semiconductor plates, which are removable at the position of the measurement sample and the position of the detection means, respectively, are provided and are opposite to each other on a diagonal line of the semiconductor plate. A Wheatstone bridge is formed by applying a DC voltage between the two ohmic electrodes, and when X-rays are incident, a current flowing between the remaining two ohmic electrodes is applied to the drive device of the goniometer and/or The present invention is characterized in that at least the position of the measurement sample, the inclination of the measurement sample, and the position of the detection unit are automatically adjusted as control signals for the drive device of the detection unit.

[Function/principle of the invention]

The present invention utilizes the internal photoelectric effect of semiconductors. As shown in Figure 2, ohmic electrodes 2, 3, 4, 5 are provided at the four corners of a square semiconductor board l, and a constant DC voltage is applied between the two diagonally opposing electrodes 2 and 4. A high precision ammeter 7 is connected between the other two opposing electrodes 3 and 5. FIG. 3 shows its electrical equivalent circuit. As long as the semiconductor board 1 is a highly accurate and uniform resistor, the semiconductor board 1 can be regarded as a resistance circuit in which 4 (solid resistances R, , R2, R3, and R4 are connected in a bridging shape) as shown in Fig. 3. Therefore, these resistors, the constant voltage source 6, and the ammeter 7 constitute a Wheatstone bridge.

When the semiconductor board 1 is irradiated with an X-ray beam, carriers are generated locally in the irradiated area, and the conductivity of that area changes. For this reason, when the X-ray beam is irradiated to a position deviated from the center of the semiconductor board 1, for example, as shown by circle 8 in FIG. Equilibrium condition R1・R3==R2・
R4 collapses, and the ammeter 7 detects a minute current. Therefore, by adjusting the irradiation position of the X-ray beam so that the current value of the ammeter 7 is minimized, the X-ray beam can be aligned accurately with the center of the semiconductor plate 1.

If a Wheatstone brigade using such a semiconductor board is used in an X-ray diffraction device, the X-ray beam can be accurately incident on the measurement sample, and the X-ray beam emitted from the sample can be accurately guided to the detector or film. This makes it possible to automate the device.

〔Example〕

FIG. 1 is a schematic perspective view of an automatic X-ray diffraction apparatus that is an embodiment of the present invention. This device basically consists of an X-ray source 1
0, a goniometer 11 that holds a measurement sample, and a detector 12. The goniometer 11 has a support section 13. which removably supports a sample and a semiconductor plate to be described later on its head. X-axis goni 14th. Y-axis goni 15th. It is composed of a 16th Z-axis goni and is provided on the sample stage 17. X-axis goni 14th. The 15th Y-axis goni and the 16th Z-axis goni have rotational axes in the x, y, and z coordinate axes shown in the figure, and are drive devices 18 equipped with servo motors and the like.
rotated by Further, the sample stage 17 is moved in the x and z directions by a drive device 18.

The detector 12 is provided on a detector stage 19,
A support section 20 to which a semiconductor board, which will be described later, can be attached and detached is attached to the front surface of the detector 12 on this detector stage.

The detector stage 19 is moved by a drive device 21 including a servo motor or the like to move x / , y l ,
It is moved in the x' and z' directions of the z' coordinate.

The support portion 13 of the goniometer 11 can removably support the semiconductor board 22 . This semiconductor plate is a thin film or thin square semiconductor having a size comparable to the sample to be measured. Semiconductor materials can be any semiconductor material, including intrinsic semiconductors such as silicon and germanium, impurity semiconductors made by adding impurities to these materials, and single crystal or polycrystalline materials, as long as they can provide accurate and uniform resistance. may also be used. Furthermore, regarding its thickness,
The thickness shall be appropriately selected so as to satisfy the above-mentioned Wheatstone bridge equilibrium conditions.

As explained in FIG. 2, ohmic electrodes (not shown) are provided at the four corners of such a semiconductor board 22, and lead wires 23 and 24 are connected from these ohmic electrodes, respectively.
, 25.26 are drawn out. Lead wires 23 and 2 drawn out from diagonally opposing ohmic electrodes
A DC constant voltage source 27 is connected between the ohmic electrode 5 and the lead wires 24 and 26 drawn out from the remaining ohmic electrodes are connected to the drive device 18.

On the other hand, the support portion 20 of the stage 19 of the detector 12 can also removably support a semiconductor board 28 similar to the semiconductor board 22. In this case, the size of the semiconductor board 28 is made large enough to cover the detection surface of the detector 12. This semiconductor board 2
Ohmic electrodes (not shown) are provided at the four corners of 8.
Lead wires 29.3 from each of these ohmic electrodes
0.31.32 is drawn. A DC constant voltage source 33 is connected between lead wires 29 and 31 drawn out from diagonally opposing ohmic electrodes, and lead wires 30 and 32 drawn out from the remaining ohmic electrodes.
is connected to the drive device 21. These lead wires 30
．． 32 is further connected to the drive device 1 via lead wires 34 and 35.
8 is connected.

In the automatic X-ray diffraction apparatus having the above structure, first, the semiconductor plate 22 is attached to the support part 13 in the head of the goniometer 11. From the X-ray source 10, X is emitted parallel to the y-axis.
It is assumed that a ray beam is emitted, and the semiconductor plate 22 is arranged perpendicular to the X-ray beam. In this state, the X-ray source 10
The power is turned on and the semiconductor board 22 is irradiated with an X-ray beam. Then, the sample stage 17 is moved in the x and z directions by the drive device 18 so that the current flowing through the lead wires 24 and 26 of the semiconductor board 22 is minimized. As explained in FIG. 2, when the X-ray beam is irradiated to the center of the semiconductor plate 22, the Wheatstone bridge equilibrium condition is established and the flowing current is minimized. Adjusted to illuminate the center. Such an operation is automatically performed by the drive device 18 detecting the current flowing through the lead wires 24 and 26 of the semiconductor board 22 as a control signal. When the adjustment of the incident position of the X-ray beam is completed, the power to the X-ray source 10 is turned off, the semiconductor plate 22 is removed from the support part 13, the sample crystal is attached to the same position, and the Z-axis goni is rotated for a predetermined number of times at the 16th rotation. Set the angle of incidence to a reasonable value. This operation is automatically performed by a servo motor provided within the drive device 18.

Next, the semiconductor board 28 is attached to the support part 20 of the detector stage 19.
Attach to. Unlike the detector 12, this semiconductor board is characterized in that it can sensitively measure minute positional fluctuations. With the semiconductor board 28 attached to the support part 20,
The power to the radiation source 10 is turned on again to emit an X-ray beam.

The emitted X-ray beam is accurately incident on the center position of the sample crystal by the above-mentioned adjustment, and is emitted from the sample. The X-ray beam emitted from the sample enters the semiconductor plate 28. Then, similarly to the adjustment of the sample stage 17, the detector stage 19 is moved in the x' and z' directions by the drive device 21 so that the current flowing through the lead wires 30 and 32 of the semiconductor board 28 is minimized. The current is the best.

The X-ray beam emitted from the sample enters the center of the semiconductor plate 28 at the position where it becomes smaller. In order to adjust the position of the detector in this way, the drive device 21 connects the leads 30.3 of the semiconductor board 28.
This is done automatically by detecting the current flowing through 2.

The current flowing through lead wires 30 and 32 further flows through lead wire 3.
4.35 to the drive device 18, and the X-axis goni first
4 and Y-axis goni are used as control signals for the 15th adjustment. The drive device 18 rotates the 14th X-axis goni and the 15th Y-axis goni so that this control signal, that is, the current, is minimized and corrects the verticality of the sample (so-called
Perform tilt correction). These operations are automatically performed by a servo motor provided within the drive device 18.

After the position, inclination, and detector position of the measurement sample are accurately determined as described above, the semiconductor board 2 is
8 from the support 20, the measurement is started.

Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and it goes without saying that various modifications and changes can be made within the scope of the present invention. for example,
A goniometer can also be used to support the detector, in which case not only the position but also the inclination of the detector can be adjusted.

Also, a film may be placed in place of the detector.

【Effect of the invention〕

As explained above, according to the automatic X-ray diffraction apparatus of the present invention, the X-ray beam position, measurement sample position, and detector position are uniquely determined, making it possible to obtain highly reproducible data. . This is particularly useful for evaluating crystallinity by measuring at half-maximum of the rocking curve.

In addition, manual adjustment by the operator is unnecessary, so
radiation exposure can be avoided, thus solving the safety problem for workers.

Furthermore, compared to conventional X-ray diffraction equipment that has a large number of detectors arranged side by side that can detect minute positional fluctuations, it is possible to obtain an automatic X-ray diffraction equipment that is inexpensive because it uses a semiconductor board and uses a Wheatstone bridge. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a schematic perspective view showing an embodiment of the automatic X-ray diffraction apparatus of the present invention, Fig. 2 is a diagram showing a Wheatstone bridge using a semiconductor board, and Fig. 3 is an equivalent circuit diagram of Fig. 2. . 10...X, radiation source 11...goniometer 12...detector 13.20...support part 14...X axis goni 15th...Y axis Goniometer 16...2-axis gonier 17...Sample stage 18.21...Driver 19...Detector stage 22.28...Semiconductor plate 27.33...DC constant voltage source

Claims (1)

[Claims] (1) An X-ray source, a goniometer that supports a measurement sample that is irradiated with X-rays emitted from the X-ray source, a means for detecting the X-rays that have passed through the measurement sample, and ohmic electrodes provided at four corners. square-shaped first and second electrodes which are detachably attached to the position of the measurement sample and the position of the detection means, respectively.
A Wheatstone bridge is formed by applying a DC voltage between the two ohmic electrodes facing each other diagonally on the semiconductor board, and when X-rays are incident, the remaining two ohmic electrodes A current flowing between the electrodes is used as a control signal for a drive device of the goniometer and/or a drive device for the detection means to automatically adjust at least the position of the measurement sample, the inclination of the measurement sample, and the position of the detection means. Automatic X-ray diffraction equipment.