CN103175857B - Device specially used for grazing incidence XAFS (X-ray Absorption Fine Structure) experiment and regulating method of device - Google Patents

Abstract

Disclosed is a device dedicated to grazing incidence XAFS experiments and its adjustment method, wherein the device includes: a device for generating X-rays required for grazing incidence XAFS experiments; a front slit to limit the size of X-rays; a first lift The first lifting table makes the front slit vertically lift; the sample holder carries the sample; the rotating table makes the sample on the sample holder rotate to obtain the required X-ray grazing incidence angle; the second lifting table makes the rotating table vertically The rear slit limits the size of the total reflection X-ray; the third lifting platform makes the rear slit vertically ascending and descending; the first detector detects the fluorescent signal emitted from the sample; the second detector , to detect total reflection X-ray signals. By adopting the device and method, the initial position of the sample can be quickly and accurately set, and the angle of the sample can be adjusted precisely, and the experimental detection data of the sample can be obtained with a high signal-to-noise ratio, and a high-quality grazing incidence XAFS experimental spectrum can be obtained.

Description

Device and its adjustment method dedicated to grazing incidence XAFS experiments

technical field

The present invention relates to a modern material structure analysis method - synchrotron radiation experiment method, in particular to a device specially used for grazing incidence X-ray Absorption Fine Structure (X-ray Absorption Fine Structure, XAFS) experiment and an adjustment method of the device.

Background technique

The synchrotron radiation XAFS spectrum experiment system has become an effective means to study the structure of matter, serving multidisciplinary fields, such as life sciences, new materials, environmental health, and industrial applications.

XAFS spectra were determined by photon energy scanning using a twin crystal monochromator. The monoenergetic beam from the monochromator is incident on the sample, and the sample absorbs different photons with different energies, and the XAFS spectrum can be obtained by detecting the change of the light intensity before and after the sample with the photon energy. The structural information in the sample can be obtained by analyzing the XAFS spectrum.

With the development of energy, environment and new material science and the deepening of related scientific research, people need to know the structural properties of thin films, device surfaces, solid-solid and solid-liquid interfaces with various functions. However, the conventional XAFS experimental system Structural information on the sample surface was not available. Thus, the grazing incidence XAFS (Grazing-incidence Absorption Fine Structure, GXAFS) spectrum experimental system appeared.

When the X-ray is incident on the material surface at a very small angle, its penetration depth becomes sharply smaller. When the grazing incidence angle of the X-ray is less than a material-related specific angle (such as the critical angle), the incident X-ray is completely reflected , only interact with the surface layer of the material, so that the emitted X-rays only contain the structural information of the surface layer of the material. This phenomenon is the physical basis of grazing incidence XAFS spectroscopy experiments.

Some foreign laboratories, such as KEK (National High Energy Physics Laboratory) and SPRING-8 in Japan, ESRF (European Synchrotron Radiation Facility) in France, APS (American Physical Society), ALS (Advanced Light Source Synchrotron Radiation Facility) and BNL in the United States (Brookhaven National Laboratory), domestic laboratories such as Hefei National Synchrotron Radiation Laboratory and Beijing Synchrotron Radiation Laboratory have successively developed XAFS experimental methods for various thin film samples, and obtained some solid surface, interface and The structure of the thin film has obtained properties such as surface catalysis and chemical adsorption, surface and interface atomic structure reconstruction, diffusion and stress relaxation. However, in experiments, how to improve the signal-to-noise ratio and reduce the interference of stray light or diffraction peaks according to the characteristics of X-ray sources and detectors is still a very challenging topic.

The existing general solution is to use the θ-2θ angle meter, and its setting principle is shown in Figure 1. Figure 1 schematically shows the schematic diagram of the θ-2θ rotator used in the grazing incidence XAFS experiment in the prior art, the X-rays passing through the monochromator are incident on the sample through the front ionization chamber, the sample stage is fixed on the axle seat, and the axle seat itself It can rotate around the central axis of the goniometer (theta rotation). The detector (usually a NaI scintillation detector) is fixed on the shaft arm, and the shaft arm can also rotate around the axis (2θ rotation). The entire turntable is placed on an electric lifting platform to adjust its vertical height. A fluorescence ionization chamber is fixed on the turntable base above the sample stage to receive the fluorescence signal of the sample.

This setup has the following problem: the initial position of the sample is difficult to locate precisely. Also, the angle of rotation of the sample in this setup is difficult to adjust precisely. In addition, the detection noise of this setup is large, and the quality of the spectrum is not high.

Contents of the invention

In order to overcome one or more of the above-mentioned problems in the prior art, embodiments of the present application provide a device dedicated to grazing incidence XAFS experiments and an adjustment method for the device.

The embodiment of the present application provides a device dedicated to grazing incidence XAFS experiments, including:

means for generating the x-rays required for said grazing incidence XAFS experiments;

a front slit for limiting the size of the X-rays emitted by the X-ray source;

a first lifting platform, used to install the front slit, and make the front slit lift in a direction perpendicular to the direction of the X-ray optical axis;

a sample holder for carrying a sample whose surface interacts with the X-rays emerging from the front slit;

A rotary table, used to install the sample holder, and make the sample on the sample holder rotate, so as to obtain the required X-ray grazing incidence angle;

The second lifting platform is used to install the rotating platform, and make the rotating platform lift in a direction perpendicular to the direction of the X-ray optical axis;

a rear slit for defining the size of the totally reflected x-rays after interacting with the surface of the sample;

a third lifting platform, used to install the rear slit, and make the rear slit move up and down in a direction perpendicular to the X-ray;

The base lifting part is used to install the first lifting platform, the second lifting platform and the third lifting platform, so that the first lifting platform, the second lifting platform and the third lifting platform are in contact with the third lifting platform The X-rays are raised and lowered in a direction perpendicular to the optical axis direction;

a first detector for detecting a fluorescent signal emitted from said sample;

The second detector is used to detect the X-ray signals emitted from the rear slit.

On the basis of the foregoing structure, it may further include a slit assembly disposed between the sample holder and the first detector; the slit assembly includes a set of non-parallel blades and has a focal point. And the distance from the centerline of the sample to the table top of the rotating stage is the focal length of the slit assembly.

On the basis of the foregoing embodiments, a light shield may be provided on the first detector.

The embodiment of the present application also provides a method for adjusting the aforementioned device, including:

Adjusting the base lifting part so that the base lifting part reaches a vertical height matching the collimated beam;

Opening the front slit, removing the sample, and adjusting the height of the rear slit in the direction perpendicular to the optical axis of the X-ray through a third lift until the output of the second detector reaches the maximum;

Adjust the slit width of the front slit, and adjust the height of the front slit in the direction perpendicular to the optical axis of the X-ray through the first lifting platform until the output of the second detector reaches the maximum;

The sample is placed on the sample holder, and the height of the sample holder in the direction perpendicular to the optical axis of the X-ray is adjusted by the second lifting platform until the output of the second detector reaches half of the maximum; then the rotary table is driven, until the output of the second detector reaches the maximum; repeat the steps of vertically adjusting the sample holder until the output of the second detector reaches half of the maximum, and rotate the turntable in both clockwise and counterclockwise directions When , the outputs of the second detectors all decrease.

On the basis of the above steps, it may also include: rotating the turntable according to the required grazing incidence angle; setting the distance from the rear slit to the sample holder, according to the grazing incidence angle, the rear slit the distance to the sample holder, calculate and set the vertical position of the rear slit; rotate the turntable until the output of the second detector reaches the maximum value.

The device dedicated to the grazing incidence XAFS experiment provided by the embodiment of the present application replaces the structure of the sample holder and the detection part in the conventional XAFS experimental system, and can be combined with the conventional XAFS experimental system to form hardware with the function of realizing the grazing incidence XAFS experiment environment.

Using the device dedicated to grazing incidence XAFS experiments provided by the embodiment of the present application and the adjustment method of the device, after adjusting the slit width and vertical height of the front and rear slits, the sample is placed on the sample holder and adjusted by the second lifting platform. The height of the sample holder in the vertical direction, and then drive the rotary stage until the output of the second detector reaches the maximum; repeat the steps of adjusting the sample holder vertically until the output of the second detector reaches half of the maximum, and rotate clockwise and When the turntable is turned counterclockwise in both directions, the output of the second detector decreases. Through such an adjustment method, the sample can be adjusted to the center of the beam and the surface is parallel to the beam, so that the initial position of the sample can be quickly and accurately set, and the angle of the sample can be adjusted accurately, and the experiment of the sample can be obtained with a high signal-to-noise ratio Detect data and obtain high-quality grazing incidence XFAS experimental spectra.

In this device, two high-sensitivity detectors are used, which can simultaneously detect the fluorescence generated by the sample and the total reflection X-ray signal. Since the intensity of the X-ray signal generated by the sample in the grazing incidence state is lower than that generated by the sample in the normal incidence state, the high-sensitivity detector can ensure the quality of the spectrum. Moreover, the second detector supports sample position setting, so that a θ-2θ detection mode is formed between the second detector and the sample. In addition, in this device, by setting a light shield on the detector port of the fluorescence detector (that is, the first detector), the scattering background caused by X-ray signal scattering when propagating in the air is reduced, reducing the Detect noise and improve the quality of spectrum acquisition.

During the XAFS spectrum acquisition process, the silicon substrate of the sample will produce diffraction peaks, and the existence of the diffraction peaks will destroy the XAFS spectrum. Diffraction peaks are often excited by the exposure of the silicon substrate at the front of the sample to X-rays. By applying the device provided in the embodiment of this application and fine-tuning the vertical position of the sample, the generation of diffraction peaks can be avoided, thereby solving the problem of semiconductor surface structure. Test questions.

In addition, due to the rotation error of the turntable, it is possible that the position of the sample does not reach the exact grazing incidence angle after the turntable turns. Using the adjustment method provided by the embodiment of the present application, after rotating the rotary stage according to the required grazing incidence angle, set the distance from the rear slit to the sample holder, and combine the θ-2θ relationship according to the grazing incidence angle, the distance from the rear slit to the sample holder , calculate and set the vertical position of the rear slit, and then turn the rotary table until the output of the second detector reaches the maximum value. In this way, the rotation error of the rotary table is eliminated, and the precise adjustment of the rotation angle of the sample is realized.

The above and other objects, features and advantages of the present invention will be more apparent through the following description of preferred embodiments with reference to the accompanying drawings.

Description of drawings

Fig. 1 schematically shows the schematic diagram of the θ-2θ goniometry used in the grazing incidence XAFS experiment in the prior art;

Figure 2 schematically shows the basic principle of grazing incidence XAFS spectroscopy experiment;

Fig. 3 schematically shows a side-view structure diagram of a device dedicated to grazing incidence XAFS experiments according to an embodiment of the present application;

Figure 4 schematically shows a schematic diagram of the relative positions of a rotary table and a sample in an embodiment of the present application;

Fig. 5 schematically shows a schematic diagram of a fluorescent X-ray detector with the slit assembly;

Figure 6 schematically shows the flow chart of the adjustment method of the device dedicated to grazing incidence XAFS experiments according to the embodiment of the present application

Figure 7A and Figure 7B show a schematic diagram of the adjustment of the initial position of the sample in the embodiment of the present application;

FIG. 8 schematically shows a mechanical structure diagram of a device dedicated to grazing incidence XAFS experiments according to an embodiment of the present application;

Fig. 9 schematically shows a grazing incidence XAFS spectrum obtained by applying the device and adjustment method provided by the embodiment of the present application.

Detailed ways

Before describing the device dedicated to the grazing-incidence XAFS experiment of the embodiment of the present application, the basic principle of the grazing-incidence XAFS spectrum experiment will be described first.

Figure 2 schematically shows the basic principle of grazing incidence XAFS spectroscopy experiments. The X-ray 11 is grazingly incident on the sample S at a grazing incidence angle slightly smaller than the critical angle, and the incident X-ray 11 is fully emitted on the surface of the sample S, and only interacts with the material on the surface of the sample S with a thickness of several nanometers to tens of nanometers (specifically The penetration depth is related to factors such as the energy of X-rays and the material itself). The fluorescence 13 generated on the surface contains the structural information of the material on the surface of the sample. The single-energy X-ray scanning is performed on the absorption edge of the detection element, and the fluorescence 13 is received by the fluorescence detector FD at the same time, so as to obtain the surface XAFS spectrum of a certain depth of the sample.

Next, the device dedicated to the grazing incidence XAFS experiment of the embodiment of the present application will be described.

Fig. 3 schematically shows a side-view structural diagram of a device dedicated to grazing incidence XAFS experiments according to an embodiment of the present application, the device includes: a device 201 for generating X-rays required for grazing incidence XAFS experiments, a front slit 202, The first lifting platform 203 , the sample holder 204 , the rotating platform 205 , the second lifting platform 206 , the rear slit 207 , the third lifting platform 208 , the first detector 209 and the second detector 210 .

Wherein, the front slit 202, the first lifting platform 203, the sample holder 204, the rotating platform 205, the second lifting platform 206, the rear slit 207, the third lifting platform 208, the first detector 209 and the second detector 210 can be All are located on a base lifting part 211, and the base lifting part 211 is used to install the first lifting platform 203, the second lifting platform 206 and the third lifting platform 208, so that the first lifting platform 203, the second lifting platform 206 and the The third elevating table 208 simultaneously elevates in a direction perpendicular to the X-ray optical axis direction. The direction of the optical axis of the X-rays may be shown by the dotted line F in FIG. 3 .

The base lifting part 211 may include an installation base plate 211a and a fourth lift platform 211b, the installation base plate 211a is used for installing the first lift platform 203, the second lift platform 206 and the third lift platform 208, and the fourth lift platform 211b is used for The mounting substrate 211a is mounted such that the mounting substrate 211a is raised and lowered in a direction perpendicular to the X-ray optical axis direction. The fourth lifting platform 211b can be a manual or electric lifting platform. The height of the entire device in the vertical direction can be adjusted through the base lifting part 211 .

The base lifting part 211 can be fixed on the slider 212, so that the whole device can slide in a direction parallel to the X-ray optical axis.

In the apparatus shown in FIG. 3 , the apparatus 201 for generating X-rays required for grazing incidence XAFS experiments can have various structures. For example, the device 201 may include a synchrotron radiation light source, a twin-crystal monochromator, and the like. The synchrotron radiation light source covers visible light to hard X-rays of hundreds of keV, and has a series of advantages such as high intensity, high collimation, small emission angle, broad spectrum, time structure, polarization, certain coherence, and accurate calculation. . According to the Bragg formula, the single-energy adjustable X-ray energy scanning required by the grazing incidence XAFS experiment can be realized by using the double crystal monochromator. Of course, the device 201 may also adopt other structures capable of generating required X-rays.

The front slit 202 is used to limit the size of the X-rays emitted by the device 201 for generating X-rays required for grazing incidence XAFS experiments. The slit width of the front slit 202 can be adjusted manually.

The first lifting platform 203 is disposed under the front slit 202 for making the front slit 202 vertically lift. The first lifting platform 203 can be a lifting platform of the type KZG06030-C from Suruga, Japan. The adjustment accuracy of the lifting platform is 0.05 μm. The lifting platform can be driven by a DS102 controller (a stepping motor controller). Realize manual or automatic control.

The sample holder 204 is used to carry the sample S. The X-rays emitted from the front slit 202 interact with the sample S on the sample holder 204 to generate fluorescence and total reflection light.

The rotating stage 205 is used to install the sample holder 204 and make the sample holder 204 (that is, make the sample S) rotate to obtain a desired X-ray grazing incidence angle. The rotation axis of the rotary table 205 may be located at the intersection of the dashed lines F and L in FIG. 3 and be perpendicular to the paper. The surface of the sample S can also be perpendicular to the paper. When the rotary table 205 rotates, the sample S rotates, and the grazing incidence angle of X-rays also changes.

One of the design points of the sample holder 204 is to make the rotation axis of the rotating stage 205 pass the surface of the sample S along the extending direction of the surface of the sample S, so that the vertical movement of the sample will not occur when the grazing incidence angle of the sample changes. Fig. 4 schematically shows a schematic view of the relative position of a rotary table and the sample in the embodiment of the present application, in this figure, the rotation axis of the rotary table 205 (as shown by the dotted line) passes through the surface of the sample along the direction in which the surface of the sample S extends .

The sample holder 204 can be designed as a detachable structure, which facilitates the installation of the sample S.

The second lifting platform 206 is used to install 205 the rotating platform, and make the rotating platform 205 rise and fall in a direction perpendicular to the direction of the X-ray optical axis. The second lifting platform 206 can also be a lifting platform of the model KZG06030-C from Suruga, Japan. The rotary table 205 can be a rotary table of the type KRW04360 from Suruga, Japan, and the adjustment accuracy is 10 arc seconds. Both the rotating platform 205 and the second lifting platform 206 can be driven by the DS102 controller, and can be controlled manually or automatically.

Through the rotating table 205 and the second elevating table 206, vertical lifting of the sample S and setting of the rotational position can be performed.

The rear slit 207 is used to define the size of the totally reflected X-rays after interacting with the surface of the sample S. The rear slit 207 is a fixed width slit. Slits with different slit widths can be selected as the rear slit 207 .

The third lifting table 208 is used to install the rear slit 207 and make the rear slit 207 rise and fall in a direction perpendicular to the X-ray. The third lifting platform 208 can also adopt the lifting platform of the model KZG06030-C of Suruga, Japan. The third lifting platform can also be driven by DS102 controller, which can realize manual or electric control.

The first detector 209 is a fluorescence detector for detecting fluorescence signals emitted from the sample S. For example, a fluorescence detector model LYTLE can be used. The probe face of the LYTLE fluorescence detector is vertically downward to receive the fluorescence signal emitted from the sample S. The fluorescence detector 209 can be arranged on the detector support 214, and the detector support 214 can be arranged on the second lifting platform 206, and a fixed distance is kept between the fluorescence detector 209 and the sample holder 204, and the detector 209 is synchronized with the sample holder 204 lift.

A slit assembly (not shown in the figure) may be provided between the fluorescence detector 209 and the sample holder 204 . The slot assembly may include a set of non-parallel blades and have a focal point. The distance from the midline of the sample S (as shown by the dotted line in Figure 4) to the slit assembly is the focal length of the slit assembly. Specifically, the slit assembly may use a fluorescent x-ray detector (Fluorescent x-ray detector) produced by EXAFS. Fig. 5 schematically shows a schematic diagram of a fluorescent X-ray detector with the slit assembly. In the embodiment of the present application, the slit assembly provided by the company is separated from the fluorescent X-ray detector and used alone to achieve the purpose of the present invention. By using the slit assembly, X-rays in all directions at the focal point can be received by the fluorescence detector 209 , thereby maximizing the X-rays received by the fluorescence detector 209 .

In addition, the mouth of the fluorescent detector 209 can be provided with a shading cover to reduce the scattering background caused by scattering of X-ray signals when propagating in the air.

The second detector 210 is used to detect the X-ray signals emitted from the rear slit 207 . The second detector 210 can be a photodiode (PD), which can detect the intensity of X-rays emitted from the rear slit 207 . The second detector 210 can be installed on the third lifting platform 208 together with the rear slit 207 , so that both the second detector 210 and the rear slit 207 have a degree of freedom of adjustment in the vertical direction.

The third lifting platform 208 can be installed on the linear sliding platform 215, through which the linear sliding platform 215 can be manually adjusted horizontally and over a long distance. The sliding direction of the third lifting platform 208 is parallel to the optical axis direction of X-rays. Since both the rear slit 207 and the second detector 210 are arranged on the third lifting platform 208, the rear slit 207 and the second detector 210 can also slide in the horizontal direction. That is to say, the rear slit 207 and the second detector 210 not only have an adjustment degree of freedom in the vertical direction, but also have an adjustment degree of freedom in the horizontal direction. By sliding the rear slit 207 and the second detector 210 in the horizontal direction, the horizontal distance between the rear slit 207 and the sample S can be precisely adjusted.

In addition, in the device shown in FIG. 3 , both the first lifting platform 203 and the second lifting platform 206 can be installed on the spacer 213 , which is convenient for adjusting the vertical heights of the first, second and third lifting platforms.

The adjustment method of the device shown in Fig. 3 dedicated to grazing incidence XAFS experiments will be described below. FIG. 6 schematically shows a flow chart of an adjustment method of a device dedicated to grazing incidence XAFS experiments according to an embodiment of the present application. The method comprises the steps of:

Step S31 , adjusting the base lifting part so that the base lifting part reaches a vertical height matching the collimated light beam.

The adjustment process is the preparatory work before the XAFS experiment, and the device 201 does not need to emit X-rays, so the adjustment can be made by simulating the X-ray source through a collimated light source whose light output direction is consistent with that of the X-rays. Specifically, X-ray sensitive paper can be used to expose to X-rays at two points, and the beam direction of the collimated light source can be determined by the spatial positions of the two spots. The collimated light source can be a collimated laser.

In step S31, a rough adjustment is performed, and the entire device is raised to an appropriate height based on the collimated light beam.

Step S32, open the front slit, remove the sample, and adjust the height of the rear slit in the direction perpendicular to the optical axis of the X-ray through the third lifting platform until the output of the second detector reaches the maximum. At this time, it indicates that the rear slit is collimated with the beam center of the collimated light source, that is, with the beam center of the X-ray.

Step S33 , adjusting the slit width of the front slit, and adjusting the height of the front slit in the direction perpendicular to the optical axis of the X-ray through the first lifting platform until the output of the second detector reaches the maximum. At this time, it shows that both the front and rear slits are collimated with the beam center of the collimated light source, that is to say, with the beam center of the X-ray. By setting in this way, the position of the beam between the front and rear slits and the cross-sectional size of the beam are both limited.

Step S34, the sample is placed on the sample holder, and the height of the sample holder in the direction perpendicular to the optical axis of the X-ray is adjusted through the second lifting platform until the output of the second detector reaches half of the maximum value; then the rotary table is driven , until the output of the second detector reaches the maximum; repeat the steps of adjusting the sample holder vertically until the output of the second detector reaches half of the maximum, and when the turntable is rotated clockwise and counterclockwise, the second detector The output of the device is reduced. This indicates that the surface of the sample is parallel to the collimated beam and that the sample is in the middle of the beam.

Specifically, as shown in FIG. 7A and FIG. 7B , FIG. 7A and FIG. 7B show a schematic diagram of adjusting the initial position of the sample in the embodiment of the present application. For ease of illustration, the size of the collimated beam is exaggerated in FIGS. 7A and 7B .

If the surface of the sample is not parallel to the collimated beam, and the sample is not located in the middle of the collimated beam, as shown in Figure 7A, then when the rotating stage is rotated so that the sample rotates counterclockwise, the section of the collimated beam blocked by the sample increases, the second The output of the detector decreases. However, when the rotating stage is rotated so that the sample rotates clockwise, the cross-section of the collimated beam blocked by the sample becomes smaller, so the output of the second detector increases.

If the surface of the sample is parallel to the collimated beam, and the sample is located in the middle of the collimated beam, as shown in Figure 7B, when the sample is rotated clockwise and counterclockwise, the cross section of the collimated beam blocked by the sample increases , the output of the second detector decreases.

Step S34 is actually a "recovery" process, through the adjustment of step S34, the sample is located at a position where the grazing incidence angle is zero.

After the above-mentioned steps S31 to S34, the rapid and accurate setting of the initial position of the sample is completed.

The adjustment method provided in the embodiment of the present application may also include the following steps:

Step S35 , rotating the rotary table according to the required grazing incidence angle (for example, 0.15 degrees).

Step S36 , setting the distance from the rear slit to the sample holder, and calculating and setting the vertical position of the rear slit according to the grazing incidence angle, the distance from the rear slit to the sample holder and the relationship between θ-2θ.

According to the measurement principle of θ-2θ, when the incident light rotates θ, the second detector needs to change the angle of 2θ. Specifically, for the device shown in FIG. 3 , when the rotary table is rotated to obtain a grazing incidence angle after step S34 , the vertical position of the second detector changes.

Step S36 is equivalent to calculating and setting the vertical position of the rear slit through theoretical calculation.

Step S37, rotating the rotary table until the output of the second detector reaches the maximum value.

Due to the rotation error of the rotary table, the grazing incidence angle after the rotation in step S35 may not be accurate enough. After the vertical position of the rear slit is set in step S36, the exact position of the rear slit is obtained. By rotating the rotary table, the optical signal transmitted through the rear slit and incident on the second detector is the largest, and the sample grazing incidence can be realized. Precise adjustment of the angle.

It can be seen that the above steps S35-S37 actually play a role of checking the grazing incidence angle, thereby ensuring the precise adjustment of the grazing incidence angle.

By moving back the combination of the rear slit and the second detector, the grazing incidence angle of the sample can be calculated according to the distance from the sample to the rear slit and the vertical distance of the rear slit from its initial position.

The above adjustment methods provided in the embodiments of the present invention can be compiled into program software implemented by a computer, so that the automation of the entire adjustment method can be realized.

Fig. 8 schematically shows the mechanical structure diagram of the device dedicated to the grazing incidence XAFS experiment of the embodiment of the present application, please note that the device for generating X-rays required for the grazing incidence XAFS experiment is omitted in this figure. The whole device is built on the lifting installation plate 501, and the base platform is installed by a manual lifting platform to adjust the height of the whole device. The manual lifting platform is fixed on the slider, and the slider can move along the optical axis on the track of the test bench. This part is realized by AH long-distance translation stage 502, linear bearing assembly 510, hexagon socket screws (GBT70.1-2000) 526 and 525, and lifting installation base plate 511.

The leftmost part of the device is a front slit 509 whose width can be adjusted manually. The front slit 509 is fixed on the vertical electric lifting platform 503 through the corner plate 508 and the spacer 504, and then the front slit 509 can be adjusted in vertical position. The model of the electric lifting platform 503 is Japan Suruga KZG06030-C, and its adjustment accuracy is 0.05 μm. Electric lifting platform 503 is driven by DS102 controller, which can realize manual or automatic control.

Behind the front slit 509 is the sample rack 514, and the sample rack 514 is fixed on the vertical electric lifting table 503 and the electric turntable 506, which can realize the vertical lift and rotation spatial position setting of the sample. The model of the electric turntable 506 is Japan Suruga KRW04360, and its adjustment accuracy is 10 arc seconds. Both the electric turntable 506 and the vertical lifting platform 503 are driven by the DS102 controller, which can realize manual or automatic control. The motorized turntable 506 can be set on the turntable installation platform 505 .

A sample rack 514 is provided on a sample rack mounting plate 515 , and the sample rack 514 has a sample plate 516 . One of the design points of the sample holder 514 is to make the rotation axis of the motorized turntable 506 pass the surface of the sample along the extending direction of the surface of the sample. The sample rack 514 is detachable for easy sample installation.

An X-ray fluorescence detector 513 is installed above the sample holder 514, the model of the detector is LYTLE, and the probe surface of the detector is vertically downward to receive the fluorescence signal emitted by the sample. A fixed distance is maintained between the detector 513 and the sample holder 514 . A slit assembly (not shown in the figure) may also be provided between the detector 513 and the sample holder 514 . The detector port of the detector 513 may be provided with a shading cover to reduce the scattering background caused by scattering of the X-ray signal when propagating in the air. The detector 513 may be arranged on the corner plate 520 of the detector bracket.

The rear side of the sample holder 514 is a rear slit 518, which has a fixed slit width and is fixed by a corner plate 517 and a pressing plate 519, and slits with different slit widths can be selected for installation. Behind the rear slit 518 is a photodiode 522 mounted on the detector mounting plate 507 for detecting the intensity of X-rays passing through the rear slit 518 . Both the rear slit 518 and the photodiode 522 are installed on the vertical electric lifting platform 521, so that both the rear slit 518 and the photodiode 522 have vertical adjustment freedom. The model of the vertical electric lifting table 521 is Japan Suruga KZG06030-C, and its adjustment accuracy is 0.05 μm. The electric lifting platform 521 can be driven by the DS102 controller, and can realize manual or automatic control.

The electric lifting platform 521 is installed on a set of linear sliding platform, including a slide plate 523 and a transition plate 524, through which the linear sliding platform can carry out horizontal long-distance manual movement. The combination formed by the rear slit 518 and the photodiode 522 not only has an adjustment degree of freedom in the vertical direction, but also has an adjustment degree of freedom in the direction of the optical axis, so that the relationship between the rear slit 518 and the photodiode 522 can be precisely set in the direction of the optical axis distance between samples.

Reference numeral 537 in FIG. 8 is a washer, 538 is a hex nut (GBT6170-2000M4), and 525-536 is a hexagon socket screw (GBT70.1-2000).

At least one of the following effects can be obtained by using the device and its adjustment method dedicated to grazing incidence XAFS experiments of the present application.

The device dedicated to the grazing incidence XAFS experiment provided by the embodiment of the present application replaces the structure of the sample holder and the detection part in the conventional XAFS experimental system, and can be combined with the conventional XAFS experimental system to form hardware with the function of realizing the grazing incidence XAFS experiment environment.

Using the XAFS spectrum measurement device provided in the embodiment of the present application, the sample is adjusted to the center of the beam and the surface is parallel to the beam by using the rotating table and the second lifting table, so that the initial position of the sample can be quickly and accurately set.

In the device of the embodiment of the present application, the angle and vertical position of the sample stage plane to X-rays can be accurately set and read out, and the readout accuracy and adjustment accuracy can reach 10 arcseconds (0.003 degrees) and 0.05 μm, respectively.

In this device, two high-sensitivity detectors are used, which can simultaneously detect the fluorescence generated by the sample and the total reflection X-ray signal. Since the intensity of the X-ray signal generated by the sample in the grazing incidence state is lower than that generated by the sample in the normal incidence state, the high-sensitivity detector can ensure the quality of the spectrum. Moreover, the position of the supporting sample of the second detector is set such that a θ-2θ detection mode is formed between the second detector and the sample. In addition, in this device, by setting a hood on the detector port of the fluorescence detector, the scattering background caused by the scattering of the X-ray signal when propagating in the air is reduced, the detection noise is reduced, and the spectrum acquisition is improved. quality.

During the XAFS spectrum acquisition process, the silicon substrate of the sample will produce diffraction peaks, and the existence of the diffraction peaks will destroy the XAFS spectrum. Diffraction peaks are often excited by the exposure of the silicon substrate at the front of the sample to X-rays. By applying the device provided in the embodiment of this application and fine-tuning the vertical position of the sample, the generation of diffraction peaks can be avoided, thereby solving the problem of semiconductor surface structure. Test questions.

Fig. 9 schematically shows the grazing incidence XAFS spectrum obtained by applying the device and the adjustment method provided by the embodiment of the present application, and the spectrum includes the surface structure information of the sample. The sample was a platinum-coated silicon substrate with a 100 μm film and a grazing incidence angle of 0.15 degrees. In the figure, the abscissa is the photon energy of the incident monoenergetic X-ray, and the ordinate is the absorption coefficient of the sample.

While this invention has been described with reference to a few exemplary embodiments, it is to be understood that the terms which have been used are words of description and illustration, rather than of limitation. Since the present invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above-described embodiments are not limited to any of the foregoing details, but should be construed broadly within the spirit and scope of the appended claims. , all changes and modifications falling within the scope of the claims or their equivalents shall be covered by the appended claims.

Claims (7)

1. be exclusively used in the device that glancing incidence XAFS tests, comprise:

The device of the X ray needed for testing for generation of described glancing incidence XAFS;

Front slit, for limit described to test for generation of described glancing incidence XAFS needed for the size of X ray that sends of the device of X ray;

First lifting table, for installing described front slit, and makes described front slit be elevated on the direction vertical with the optical axis direction of described X ray;

Specimen holder, for carrying sample, the surface of described sample with interact from the X ray of described front slit outgoing;

Universal stage, for installing described specimen holder, and makes the sample on described specimen holder rotate, to obtain required X ray glancing incidence angles;

Second lifting table, for installing described universal stage, and makes described universal stage be elevated on the direction vertical with the optical axis direction of described X ray;

Rear slit, for limit with the surface interaction of described sample after the size of full-reflection X ray;

3rd lifting table, for installing described rear slit, and makes described rear slit be elevated on the direction vertical with described X ray;

Pedestal lifting unit, for installing described first lifting table, described second lifting table and described 3rd lifting table, makes described first lifting table, the second lifting table be elevated on the direction vertical with the optical axis direction of described X ray with described 3rd lifting table simultaneously;

First detector, for detecting the fluorescence signal sent from described sample;

Second detector, for detecting the X ray signal from described rear slit outgoing;

Wherein, the rotating shaft of described universal stage along the surperficial bearing of trend of described sample through the surface of described sample;

Described first detector is provided with light shield.

2. device according to claim 1, also comprises slit assembly, is arranged between described specimen holder and described first detector; Described slit assembly comprises one group of uneven blade and has focus.

3. device according to claim 2, wherein, the center line of described sample to the distance of the table top of described universal stage is the focal length of described slit assembly.

4. device according to claim 1, wherein, described second detector is arranged on described 3rd lifting table;

Described 3rd lifting table is arranged on linear slide platform, and the glide direction of described 3rd lifting table on described linear slide platform is parallel with the optical axis direction of described X ray.

5. the device according to claim arbitrary in claim 1-4, described pedestal lifting unit comprises:

Installation base plate, for installing described first lifting table, described second lifting table and described 3rd lifting table;

4th lifting table, for installing described installation base plate, makes described installation base plate be elevated on the direction vertical with the optical axis direction of described X ray.

6. a method of adjustment for the device as described in claim arbitrary in claim 1-5, comprising:

Adjusting base lifting unit, makes described pedestal lifting unit reach the vertical height matched with collimated light beam;

Open front slit, remove sample, regulate the height of described rear slit on the direction vertical with the optical axis of X ray, until the output of the second detector reaches maximum by the 3rd lifting table;

Before regulating, the seam of slit is wide, and regulates the height of described front slit on the direction vertical with the optical axis of X ray, until the output of the second detector reaches maximum by the first lifting table;

Sample is placed on specimen holder, regulates the height of described specimen holder on the direction vertical with the optical axis of X ray, until the half when output of the second detector reaches maximum by the second lifting table; Then universal stage is driven, until the output of the second detector reaches maximum; Repeated vertical regulates the step of described specimen holder, until the half when output of described second detector reaches maximum, and when clockwise and counterclockwise both direction rotates described universal stage, the output of described second detector all reduces.

7. method according to claim 6, also comprises:

Described universal stage is rotated according to required glancing incidence angles;

The distance of described rear slit to described specimen holder is set, according to described glancing incidence angles, described rear slit to the distance of described specimen holder, calculates and the upright position of described rear slit is set;

Rotate described universal stage, until the output of described second detector reaches maximal value.