JPS62226048A - Spectrochemical analysis of crystal solid - Google Patents

Abstract

PURPOSE:To improve spectral sensitivity by analyzing a crystal solid sample under the conditions under which an incident X-ray forms a standing wave in said sample. CONSTITUTION:The Bragg's condition expressed by the prescribed equation can be satisfied which the continuous X-ray generated from an X-ray light source 1 is made chromatic by a mechanism 2 for forming monochromatic light and is made incident at an incident angle theta on the crystal solid sample disposed in a sample vessel 3 and held to a rotatable holding member. The incident angle theta is fixed near the Bragg conditions and the wavelength lambda of the incident light is continuously changed by the mechanism 2. The quantity I of secondary electrons such as fluorescent X-ray generated from the sample 5 is monitored by an electron amplifier 6 or electron energy analyzer 7 and is recorded by a recorder 9a via a counter circuit 8a. An I-lambda curve is measured and the max. wavelength lambda of the electron quantity of the fluorescent X-ray quantity appearing in the I-lambda curve is determined. The photon energy of the fluorescent X-ray generated under such conditions and the number thereof are detected 10. The fluorescent X-ray spectra is determined by a recorder 9b via a counter circuit 8b, by which the kind and quantity of the element consisting the sample 5 are analyzed from the spectra obtd. in such a manner.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a method for spectroscopic analysis of crystalline solids.

(Prior Art) Fluorescence X-ray spectroscopy, for example, has been known as a spectroscopic analysis method using X-rays generated from a crystalline solid sample, and is mainly used for qualitative and quantitative analysis of crystalline solid samples. There is. This spectroscopic analysis method involves irradiating the surface of a crystalline solid sample with X-rays, and as a result of the interaction between the X-rays and the electrons of the sample's constituent atoms, the energy of the X-rays (fluorescent X-rays) emitted from the sample and its photons are determined. The number distribution (spectrum) is measured, and the types and amounts of the constituent elements, and in some cases, the state of chemical bonds, etc., are analyzed from the spectrum.

In particular, since this spectroscopic analysis method uses X-rays as incident quanta, it causes much less damage to crystalline solid samples than analysis methods that use electron beams or ions, and allows so-called non-destructive analysis, making it highly versatile. It is a sophisticated analytical method.

However, X-ray fluorescence spectroscopy is inferior to other methods such as secondary ion mass spectrometry in terms of sensitivity, for example in the analysis of trace elements in semiconductor materials, and higher sensitivity is desired. There is.

For this reason, efforts are being made to increase the intensity of incident X-rays and the sensitivity of X-ray detectors. In particular, with the recent appearance of synchrotron radiation, which is a powerful X-ray, attempts have begun to utilize synchrotron radiation as a light source for fluorescence X-ray spectroscopy. However, if such a light source is used to increase the X-ray intensity and increase the sensitivity of analysis, there is a problem that the apparatus becomes large or expensive.

On the other hand, ion desorption spectroscopy uses X-rays to analyze the types and amounts of elements constituting a solid sample, and photoelectron spectroscopy uses X-rays to analyze the types, amounts, and chemical bonding states of elements constituting a solid sample. Analytical methods are known. However, like the fluorescent X-ray spectroscopy method, these methods have a problem of low absolute detection sensitivity.

(Problems to be Solved by the Invention) The present invention was made to solve the above problems, and it is possible to improve the spectral sensitivity without increasing the incident X-ray intensity or the sensitivity of the detector. The present invention aims to provide a possible method for spectroscopic analysis of crystalline solids.

[Structure of the Invention] (Means for Solving the Problems) The present invention irradiates the surface of a crystalline solid sample with X-rays from an X-ray generator, and the interaction between the X-rays and the atoms constituting the sample causes light to be removed from the sample. In a method of measuring physical quantities of electromagnetic waves or charged particles emitted into a vacuum and thereby analyzing at least the type and amount of elements constituting the sample, the incident X-rays form a standing wave within the crystalline solid sample. This is a method for spectroscopic analysis of crystalline solids, characterized in that analysis is performed under certain conditions.

The spectroscopic analysis method of the present invention includes three analysis methods described below depending on the types of electromagnetic waves and charged particles emitted from a crystalline solid sample and the physical quantities they have to be measured.

(2) The electromagnetic waves emitted from a crystalline solid sample by X-ray irradiation are fluorescent X-rays, and the physical quantities of the fluorescent X-rays are photon energy and photon number. ) is a fluorescent X-ray spectroscopic analysis method that measures the types and amounts of sample constituent elements. In this fluorescent X-ray spectroscopy method, fluorescent X-rays emitted from a crystalline solid sample are
The atmosphere of the line does not necessarily have to be a vacuum.

(2) The electromagnetic waves emitted from a crystalline solid sample by X-ray irradiation are electron beams, and the physical quantities of the electron beams are kinetic energy and its amount, and from these kinetic energy and its amount, the types of sample constituent elements can be determined. , Melon and an electron spectroscopy method for measuring chemical bonding states.

(2) Charged particles emitted from a crystalline solid sample by X-ray irradiation are ions, and the physical quantities of the ions are mass and its amount, and from these masses and mass, the type and amount of the constituent elements of the sample can be determined. Ion desorption spectroscopy method to measure. Here, ion desorption refers to the desorption of ions from a crystalline solid sample by irradiation with light (X-rays). This is photodetachment (PI+oton S stimulated
It is also called Desovptlon; PSD). The mechanism of PSD is that (a) surface atoms undergo inner shell ionization by incident light, (b) energy is relaxed by interatomic or intraatomic Ojo transitions, and (c) as a result, several 1Sl atoms are removed from surface anion atoms. electrons are lost, (d)
Ions are desorbed by the Coulomb repulsion generated by this. Therefore, in order to improve the sensitivity of the ion desorption spectroscopy method, for example, it is sufficient to increase the inner shell ionization efficiency described in (a) above.

(Function) Next, the function of the spectroscopic analysis method of the present invention will be explained. however,
Here, a fluorescent X-ray spectroscopy method will be explained as an example.

When X-rays are incident on a crystalline solid sample near the Bragg condition,
A standing wave of X-rays is generated within the sample due to interference between the incident wave and the diffracted wave. The nodes and antinodes of the standing wave are parallel to the lattice planes of the crystal involved in diffraction, and their spacing matches that of the lattice planes. At this time, when the antinode of the standing wave is on the sample constituent atoms, the electrons in the atoms receive a strong wave field from the standing wave and are emitted from the sample due to the photoelectric effect. also occurs.

Therefore, we create conditions in which a standing wave is generated and its antinode is on the atoms constituting the crystalline solid sample, and measure the fluorescent X-ray R energy and the number of photons emitted under these conditions with a detector. If a fluorescent X-ray spectrum is obtained, the spectral intensity will increase, and the analytical sensitivity will be improved several times or more.

In addition, in the electron spectroscopy method, X-rays are incident on the crystalline solid sample near the Bragg condition to generate a standing wave, and the conditions are such that the antinode of the standing wave coincides with the atoms constituting the sample. If the kinetic energy and amount of the original electrons and original electrons are measured with a detector and a photoelectron spectrum is obtained, the intensity of the spectrum will increase and the analytical sensitivity will be improved several times over.

In addition, in the ion desorption spectroscopy method, X-rays are incident on the crystalline solid sample near the Bragg condition to generate a standing wave, and the condition is such that the antinode of the standing wave coincides with the sample constituent atoms. If the mass and amount of emitted core ions are measured with a detector and a spectrum is obtained, the analytical sensitivity can be improved several times or more.

(Embodiments of the Invention) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Example 1 Example 1 is an example related to fluorescent X-ray spectroscopy, and will be described with reference to FIGS. 1 and 2.

First, continuous X-ray light (for example, synchrotron radiation light) generated from an X-ray light source 1 is made monochromatic by a monochromating mechanism 2,
When this X-ray (wavelength λ) is made incident at an incident angle e into a crystalline solid sample 5 with, for example, a lattice spacing d, which is placed in a sample container 3 and held at a fixed angle by a rotatable holding member 4, the following results. It was possible to form an X-ray standing wave very close to the total reflection region of so-called Bragg reflection, which satisfies the Bragg condition of equation (1).

2dsine-λ ・(1) Near the Bragg condition of equation (1) above, for example, the incident angle e
is fixed (θf)L, and the wavelength of the incident light from the monochromating mechanism 2 is λ
is continuously changed, and the breath (I) of secondary electrons such as fluorescent X-rays and photoelectrons generated from the sample 5 at that time is monitored by the electron amplifier tube 6 or the electron energy analyzer 7, and the counting circuit 8a
The I-2 curve is measured by recording with the recorder 9a.

The maximum amount of electrons appearing on the I-2 curve thus obtained determines the wavelength λ (λM) of the maximum fluorescence XgH. Then, under such conditions (ef-λM), fluorescent
By obtaining a fluorescent X-ray spectrum using the recorder 9b through the 100-degree recording device, it was possible to analyze the types and amounts of the constituent elements of the crystalline solid sample from the spectrum. In this case,
The fluorescent X-ray R energy and the number of photons generated under the condition of ef-λ are detected by the ray detector 10, and the intensity of the fluorescent X-ray spectrum determined by the recorder 9b via the counting circuit 8b is set to the above conditions. The increase was markedly greater than that of the fluorescent X-ray spectrum simply measured without the use of fluorescent X-rays, so we were able to improve the analytical sensitivity by several times.

In addition, near the Bragg condition of equation (1) above, the incident light wavelength λ is fixed (λf), and the crystal solid sample 5 is intermittently rotated by the holding member 4 to continuously change the incident angle θ2. At that time, ffl (1) of secondary electrons such as fluorescent X-rays and photoelectrons generated from the sample 5 is monitored by an electron amplifier tube 6 or an electron energy analyzer 7, and recorded by a recorder 9a via a counting circuit 8a. and measure the I-9 curve. The maximum amount of electrons appearing on the I-0 curve thus obtained determines the incident angle e(0M) of the maximum amount of fluorescent X-rays. Then, by detecting the fluorescent X-ray Aζ and the number of photons generated under such conditions (λf-θM) with the X-ray detector 10, and obtaining the fluorescent X-ray spectrum with the recorder 9b via the counting circuit 8b, From this spectrum, it was possible to analyze the types and amounts of the constituent elements of the crystalline solid sample. Even in this case, the X-ray detector 10 detects 0. -0.0i. Engineering, reproduction, fluorescence, Yu&
The intensity of the fluorescent X-ray spectrum obtained in the same manner as above by detecting the number of photons and photons is significantly increased compared to the fluorescent X-ray spectrum simply measured without setting the above conditions.
We were able to improve the analytical sensitivity by several times.

Example 2 Example 2 is an example related to electron spectroscopy, and will be described with reference to FIGS. 3 and 4.

First, continuous X-ray light generated from an X-ray light source 1 is monochromated by a monochromating mechanism 2, and this X-ray (wavelength λ) is placed in a sample container 3 in which a vacuum atmosphere is created by a vacuum pump 11.
When the light is incident at an incident angle e onto a crystalline solid sample 5 with a lattice spacing d, which is held at a fixed angle by a rotatable holding member 4, all of the so-called Bragg reflections that satisfy the Bragg condition of equation (1) mentioned above are generated. We were able to form a standing wave of X-rays very close to the reflection area.

Near the Bragg condition of equation (1) above, for example, the incident angle e
(Of) L, the wavelength λ of the 4J light input from the monochromating mechanism 2 is continuously changed, and the in (1) of secondary electrons such as photoelectrons generated from the sample 5 at that time is monitored by the electron amplifier tube 6. is recorded by the recorder 9a via the counting circuit 8a, and the I
-Measure the λ curve. The wavelength λ (λM) of the maximum amount of electrons appearing on the I-λ curve thus obtained is determined. and,
The kinetic energy and the amount of electrons generated under the condition (ef-λM) are detected by the electron energy analyzer 12,
By obtaining a photoelectron spectrum using a recorder 9b via a counting circuit 8b, it was possible to analyze the types, amounts, and chemical bonding states of the constituent elements of the crystalline solid sample from the spectrum. In this case, the electron energy analyzer 12 detects the kinetic energy and its amount of electrons generated under the condition of Of-λM, and the intensity of the photoelectron spectrum determined by the recorder 9b via the counting circuit 8b is set to the above conditions. The increase was markedly greater than that of the photoelectron spectrum simply measured without the use of a photoelectron, so we were able to improve the analytical sensitivity by several times.

In addition, near the Bragg condition of equation (1) above, the incident light wavelength λ is fixed (λf), and the crystalline solid sample 5 is intermittently rotated in the vacuum atmosphere of the container 3 by the holding member 4, and the incident light is The angle θ2 is continuously changed, and m (1) of secondary electrons such as photoelectrons generated from the sample 5 are transferred to the electron amplifier tube 6.
The I-9 curve is measured by monitoring with a recorder 9a via a counting circuit 8a. The incident angle e (eM) of the maximum amount of electrons appearing on the I-9 curve thus obtained is determined. Then, the kinetic energy and the amount of electrons generated under such conditions (λf-eM) are detected by the electron energy analyzer 12, and the photoelectron spectrum is obtained by the recorder 9b via the counting circuit 8b. We were able to analyze the types, amounts, and chemical bonding states of the constituent elements of crystalline solid samples.

Even in this case, the electron energy analyzer 12 calculates λfe
The intensity of the photoelectron spectrum obtained in the same manner as above by detecting the kinetic energy and its amount of electrons generated under the conditions of M is significantly increased compared to the photoelectron spectrum simply measured without setting the above conditions. , we were able to improve the analytical sensitivity by several times.

Example 3 Example 3 is an example related to ion desorption spectrometry,
This will be explained with reference to FIGS. 3 and 4. However, in this ion desorption spectrometry, a quadrupole mass spectrometer was used in place of the electron energy analyzer 12 in FIGS. 3 and 4.

First, continuous X-ray light generated from an X-ray light source 1 is monochromated by a monochromating mechanism 2, and this X-ray (wavelength λ) is placed in a sample container 3 in which a vacuum atmosphere is created by a vacuum pump 11.
When the light is incident at an incident angle θ onto a crystalline solid sample 5 with, for example, a lattice spacing d held at a constant angle by a rotatable holding member 4, all of the so-called Bragg reflections that satisfy the Bragg condition of equation (1) mentioned above are generated. We were able to form a standing wave of X-rays very close to the reflection area.

Near the Bragg condition of equation (1) above, for example, the incident angle e
is fixed (ef) L, and the wavelength λ of the incident light from the monochromating mechanism 2 is
is continuously changed, and the amount (I) of secondary electrons such as photoelectrons generated from the sample 5 at that time is monitored by the electron amplifier tube 6, and recorded by the recorder 9a via the counting circuit 8a. Measure the curve. At this time, if fluorescent X-rays are generated from the sample 5, a semiconductor detector is used instead of an electron amplifier tube to detect the fluorescent X-rays. (1) is detected. Thus obtained l-
The maximum amount of electrons appearing in the two curves determines the maximum wavelength λ (λM) of fluorescent X-rays. And under such conditions (ef-
The mass and amount of ions generated at λM) are measured using mass spectrometer 1.
2, and by obtaining an ion desorption spectroscopic analysis spectrum using a recorder 9b via a counting circuit 8b, it was possible to analyze the types and amounts of the constituent elements of the crystalline solid sample from the spectrum. In this case, the mass and amount of ions generated under the conditions of θf-λM are detected by the mass spectrometer 12, and the intensity of the ion desorption spectrometry spectrum determined by the recorder 9b via the counting circuit 8b is determined under the conditions described above. This is a significant increase compared to the ion desorption spectrometry spectrum that was simply measured without any settings, so we were able to improve the analytical sensitivity by several times.

In addition, near the Bragg condition of equation (1) above, the incident light wavelength λ is fixed (λf) L, and the crystalline solid sample 5 is intermittently rotated in the vacuum atmosphere of the container 3 by the holding member 4, and the incident light is While the angle el is continuously changed, the IS (I) of secondary electrons such as photoelectrons generated from the sample 5 is monitored with an electron amplifier tube 6, and the amount of fluorescent X-rays (1) is monitored with a semiconductor detector. , the I-8 curve is measured by recording with the recorder 9a via the counting circuit 8a. The maximum amount of electrons appearing on the I-8 curve thus obtained determines the maximum incident angle θ (eM) of the fluorescent X-ray. Then, the mass and amount of ions generated under such conditions (λf −eu ) are detected by the mass spectrometer 12,
By obtaining the ion desorption spectroscopic analysis spectrum with the recorder 9b via the counting circuit 8b, it was possible to analyze the types and amounts of constituent elements of the crystalline solid sample from the spectrum. Even in this case, the mass spectrometer 12
The mass and amount of ions generated under the conditions of θM are detected, and the intensity of the ion desorption spectrometry spectrum obtained in the same manner as above is compared to the ion desorption spectrometry spectrum simply measured without setting the above conditions. As a result, we were able to improve the analytical sensitivity by several times.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to improve the spectral sensitivity of a crystalline solid using existing equipment without using a high-output X-ray generator or a high-sensitivity detector. Qualitative with precision
A spectroscopic analysis method capable of quantitative determination can be provided.

[Brief explanation of drawings]

Figure 1 is a schematic perspective view showing the fluorescence X-ray spectrometer used in Example 1, Figure 2 is a cross-sectional view of Figure 1, and Figure 3 is the electron spectrometer used in Example 2 or 3. A schematic perspective view showing the device (or ion desorption spectrometer), FIG.
FIG. DESCRIPTION OF SYMBOLS 1... X-ray light source, 2... Monochromating mechanism, 4... Rotatable holding member, 5... Crystal solid sample, 6... Electron amplifier tube, 7... Electron energy analyzer , 8a, 8b...
- Counting circuit, 10... X-ray detector, 11... Vacuum pump, 12... Electronic energy analyzer (or mass spectrometer). Applicant's agent Patent attorney Takehiko Suzue Figure 2 Figure 4

Claims (4)

[Claims] (1) The surface of a crystalline solid sample is irradiated with X-rays from an X-ray generator, and the physical quantities of electromagnetic waves or charged particles emitted from the sample into a vacuum due to the interaction of the X-rays and the sample constituent atoms are measured. and a method for analyzing at least the types and amounts of elements constituting a sample, characterized in that the analysis is performed under conditions in which the incident X-rays form a standing wave within the crystalline solid sample. Analysis method. (2) Electromagnetic waves emitted from a crystalline solid sample cause fluorescence
2. The method for spectroscopic analysis of a crystalline solid according to claim 1, wherein the fluorescent X-rays are fluorescent X-rays and the physical quantities thereof are photon energy and the number of photons. (3) The crystal according to claim 1, wherein the charged particles emitted from the crystalline solid sample are electron beams, and the physical quantities of the electron beams are kinetic energy and its amount. Methods for spectroscopic analysis of solids. (4) Spectroscopy of a crystalline solid according to claim 1, wherein the charged particles emitted from the crystalline solid sample are ions, and the physical quantities of the ions are mass and its amount. Analysis method.