JP2020187872A - Sample analysis method - Google Patents

Abstract

To provide a sample analysis method that enables high-resolution and temporal analysis of a sample surface using an electron beam device while introducing hydrogen into a sample.SOLUTION: A sample analysis method using an electron beam device 100 by which an electron beam is injected onto a surface 11a of a sample 11 and which detects one or more selected from electrons and X-rays emitted from the surface 11a, includes the steps of injecting an electron beam onto the surface 11a, providing a delivery and discharge unit (nozzle 12) having a delivery portion 12a and an electrode portion 12b inside the electron beam device 100, applying a voltage to the electrode portion 12b while blowing a hydrogen-containing gas from the delivery portion 12a to the surface 11a, and generating a glow discharge between the surface 11a and the electrode portion 12b.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sample analysis method.

In the development of high-strength steel, hydrogen embrittlement, in which strength and toughness are deteriorated by hydrogen, has become a major problem. However, the structural changes in materials related to hydrogen embrittlement are uncertain, and in order to elucidate the mechanism of hydrogen embrittlement, it is desirable to observe over time while introducing hydrogen into steel.

Non-Patent Document 1 proposes a method of observing the shape of the surface of a test piece with an atomic force microscope (AFM) while performing electrolytic charging in an electrolytic solution.

A. Barnoush et al., Direct observation of hydrogen-enhanced plasticity in super duples stainless steel by means of in situ electrochemical methods, Scripta Materialia, 62 (2010) 242

By the way, in recent years, as a result of repeated studies by the present inventors on hydrogen embrittlement of metal materials, hydrogen invading the material has an effect on strain distribution, phase transformation, dislocation motion, etc. caused by stress loading. However, it has gradually become clear that it is the cause of hydrogen embrittlement.

Along with this, it has become necessary to analyze changes over time in the above physical phenomena when stress is applied while hydrogen is being introduced into the material with high resolution and over a wide area. An electron beam device typified by a scanning electron microscope (SEM) is indispensable for analyzing these physical phenomena occurring in a material.

That is, it has come to be recognized that it is necessary to analyze the surface of the material with high resolution by using an electron beam device with hydrogen introduced into the material and stress is applied as necessary.

The AFM used in Non-Patent Document 1 can analyze the surface shape of a material with high accuracy, but cannot analyze strain distribution, phase transformation, dislocation motion, and the like. Further, in Non-Patent Document 1, since electrolytic charging is performed in the electrolytic solution, it is impossible to apply the technique of Non-Patent Document 1 as it is to the electron beam apparatus maintained at a high vacuum degree. Further, there is a possibility that the surface of the material is deteriorated due to a chemical reaction with the electrolytic solution, which is not preferable. In addition, there is no mention of applying stress during electrolytic charging.

An object of the present invention is to provide a sample analysis method capable of analyzing a sample surface with high resolution and over time by using an electron beam device while introducing hydrogen into the sample.

The present invention has been made to solve the above problems, and the following sample analysis method is the gist of the present invention.

(1) A method for analyzing a sample using an electron beam device that injects an electron beam onto the surface of the sample and detects one or more selected from electrons and X-rays emitted from the surface.
The step of incident the electron beam on the surface and
A discharge / discharge unit having a discharge portion and an electrode portion is provided inside the electron beam device, and a voltage is applied between the surface and the electrode portion while blowing a hydrogen-containing gas from the discharge portion to the surface. A step of applying and generating a glow discharge between the surface and the electrode portion is provided.
Sample analysis method.

(2) The discharge / discharge unit is made of a conductive material so as to function as the electrode portion, and includes a nozzle in which the discharge portion is formed.
The sample analysis method according to (1) above.

(3) The discharge / discharge unit includes a nozzle in which the discharge portion is formed and the electrode portion.
The sample analysis method according to (1) above.

(4) The electrode portion is provided on the nozzle.
The sample analysis method according to (3) above.

(5) The sample is a metallic material.
The sample analysis method according to any one of (1) to (4) above.

(6) In the step of generating the glow discharge, the magnitude of the voltage is set to 100 V or more and 5 kV or less.
The sample analysis method according to any one of (1) to (5) above.

(7) The opening cross-sectional area of the discharge portion is 1 μm ² or more and 0.01 mm ² or less.
The sample analysis method according to any one of (1) to (6) above.

(8) In the step of generating the glow discharge, the distance between the surface and the discharge portion is set to 10 μm or more and 2 cm or less.
The sample analysis method according to any one of (1) to (7) above.

(9) In the step of generating the glow discharge, the flow rate of the hydrogen-containing gas is set to 1 mL / min or more and 100 mL / min or less.
The sample analysis method according to any one of (1) to (8) above.

(10) In the step of incident the electron beam, the energy of the electron beam is set to 200 eV or more.
The sample analysis method according to any one of (1) to (9) above.

(11) In the step of incident the electron beam, the irradiation current of the electron beam is set to 10 pA or more.
The sample analysis method according to any one of (1) to (10) above.

(12) Further comprising a step of applying stress to the sample.
The sample analysis method according to any one of (1) to (11) above.

According to the present invention, it is possible to analyze the sample surface with high resolution and over time by using an electron beam device while introducing hydrogen into the sample.

It is a figure which shows the schematic structure of the electron beam apparatus used in the sample analysis method which concerns on one Embodiment of this invention. It is a figure which showed typically an example of the shape of the sample corresponding to the applied stress. It is a figure which shows the schematic structure of the electron beam apparatus used in the sample analysis method which concerns on other embodiment of this invention. It is a figure which shows the schematic structure of the electron beam apparatus used in the sample analysis method which concerns on other embodiment of this invention. It is a figure which shows the schematic structure of the electron beam apparatus used in the sample analysis method which concerns on other embodiment of this invention. It is a figure for demonstrating the size and shape of a test piece. It is a figure for demonstrating the size and shape of a wedge. It is a figure for demonstrating the discharge direction of a hydrogen-containing gas by a nozzle, and the incident direction of an electron beam. It is a figure which showed the secondary electron image acquired before and after the application of voltage.

A sample analysis method according to an embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a diagram showing a schematic configuration of an electron beam apparatus 100 used in the sample analysis method according to the embodiment of the present invention. The electron beam apparatus 100 includes, for example, an SEM.

First, the structure of the electron beam apparatus 100 used in the sample analysis method according to the embodiment of the present invention will be described. As shown in FIG. 1, the inside of the electron beam apparatus 100 is divided into a sample chamber 10, an intermediate chamber 20, and an electron gun chamber 30.

A vacuum exhaust unit 40 is provided in each of the sample chamber 10, the intermediate chamber 20, and the electron gun chamber 30. As the vacuum exhaust unit 40, for example, a vacuum pump such as a turbo molecular pump, a diffusion pump, an ion pump, a titanium sublimation pump, an oil rotary pump, or a dry pump can be used.

When analyzing the sample, the sample 11 is placed in the sample chamber 10. As for the type of sample 11, a sample having conductivity is targeted. The shape of the sample 11 is not particularly limited, and may be any shape such as a plate shape, a granular shape, a rod shape, or the like that can be placed in the sample chamber 10. Further, it can be processed into a preferable shape according to the type of stress applied to the sample 11. In the present embodiment, a case where a metal material is used as the sample 11 and a change over time in the surface of the metal material when hydrogen embrittlement occurs by applying various stresses will be analyzed as an example.

Further, a nozzle 12 is provided in the sample chamber 10. A predetermined flow rate of hydrogen-containing gas is supplied to the nozzle 12 by the flow rate controller 13 (mass flow controller), and the hydrogen-containing gas is blown onto the surface 11a of the sample 11 from the discharge portion 12a formed in the nozzle 12.

In this embodiment, the nozzle 12 is made of a conductive material. The material is not particularly limited as long as it has conductivity, and for example, stainless steel or copper can be used. It is necessary for the nozzle 12 to have conductivity in order to generate a glow discharge between the surface 11a and the nozzle 12.

The sample 11 and the nozzle 12 are connected to a power source arranged outside the sample chamber 10. When a voltage (hereinafter referred to as “power supply voltage”) is applied between the surface 11a of the sample 11 and the nozzle 12 by a power source while blowing a hydrogen-containing gas onto the surface 11a, a glow is applied between the surface 11a and the nozzle 12. A discharge occurs. The sample 11 may be an anode and the nozzle 12 may be a cathode, or the sample 11 may be a cathode and the nozzle 12 may be an anode.

If the opening cross-sectional area of the discharge portion 12a of the nozzle 12 is too large, the pressure of the hydrogen-containing gas on the surface 11a may become insufficient, and the glow discharge described later may not occur. On the other hand, if the opening cross-sectional area of the discharge portion 12a is too small, it is necessary to increase the supply pressure of the hydrogen-containing gas in order to generate glow discharge, and the nozzle 12 or the gas pipe may be damaged. Therefore, the opening cross-sectional area of the discharge portion 12a is preferably 1 μm ² or more and 0.01 mm ² or less.

Further, if the distance between the surface 11a and the discharge portion 12a is too long, the pressure of the hydrogen-containing gas on the surface 11a may become insufficient and glow discharge may not occur. On the other hand, if this distance is too short, the region where the glow discharge occurs becomes narrow, and hydrogen may be introduced into only a very small part of the sample 11. If this distance is too short, the pressure of the hydrogen-containing gas on the surface 11a becomes too high, the surface 11a is heated by the collision of hydrogen ions, an arc discharge occurs, and the elements constituting the sample 11 may evaporate. There is. Therefore, the distance between the surface 11a and the discharge portion 12a is preferably 10 μm or more and 2 cm or less. By setting the size to 2 cm or less, unexpected discharges other than the sample 11 can be sufficiently suppressed.

Further, the sample chamber 10 is provided with a detector 14. The detector 14 detects one or more selected from electrons and X-rays emitted from the surface 11a when an electron beam is incident on the surface 11a of the sample 11 at a predetermined accelerating voltage. The electrons include secondary electrons, backscattered electrons, Auger electrons and the like. Further, the detector 14 includes a secondary electron detector (SE detector), a backscattered electron detector (BSE detector), an electron backscatter diffraction detector (EBSD detector), a semiconductor detector (EDS detector), and the like. Is included.

Further, in the configuration shown in FIG. 1, the sample chamber 10 is further provided with a stress loading unit 15 for applying stress to the sample 11. The type of stress applied to the sample 11 is not particularly limited, and may be any of tensile stress, compressive stress, bending stress, and torsional stress. FIG. 2 is a diagram schematically showing an example of the shape of the sample according to the applied stress. For example, the shape may be a tensile test piece (FIG. 2a), a bending test piece (FIG. 2b), a cantilever test piece (FIG. 2c), a torsion test piece (FIG. 2d), or the like. The processing method of the sample 11 is not particularly limited, and the sample 11 may be appropriately produced by machining, electric discharge machining, focused ion beam machining, or the like. Further, the sample 11 may be provided with a notch or a pre-crack in order to limit the region where the crack occurs. There are no restrictions on the method of applying stress, and methods such as inserting a wedge into the notch and fastening the test piece with a bolt can be used.

The intermediate chamber 20 is communicated with the sample chamber 10 and the electron gun chamber 30, respectively, via the small holes 20a and 20b. By providing the intermediate chamber 20 between the sample chamber 10 and the electron gun chamber 30 to form a differential exhaust system, even if hydrogen-containing gas is supplied into the sample chamber 10, the electron gun chamber 30 has a high degree of vacuum. It will be possible to maintain. In the example shown in FIG. 1, the number of intermediate chambers 20 is one, but a plurality of intermediate chambers 20 may be provided.

An electron gun 31 for irradiating an electron beam is provided in the electron gun chamber 30. The type of the electron gun 31 is not particularly limited, and for example, a field emission type or filament type electron gun can be used. An electronic lens and a scanning coil (not shown) are provided in the electron gun chamber 30, and by controlling these, an electron beam is scanned on the surface 11a of the sample 11.

As described above, in the configuration shown in FIG. 1, a nozzle 12 made of a conductive material and having a discharge portion 12a formed therein is provided in the sample chamber 10. However, the present invention is not limited to this, and it is sufficient that the sample chamber 10 is provided with a discharge / discharge unit having a discharge portion 12a and an electrode portion 12b. That is, in the configuration shown in FIG. 1, the nozzle 12 itself functions as the electrode portion 12b.

3 to 5 are diagrams showing a schematic configuration of an electron beam apparatus 100 used in the sample analysis method according to another embodiment of the present invention. In the configuration shown in FIG. 3, the annular electrode portion 12b is provided on the outer peripheral surface of the nozzle 12 on which the discharge portion 12a is formed. In this case, the nozzle 12 does not have to be conductive. Further, the discharge portion 12a may be made of a conductive material and may function as the electrode portion 12b.

In the configuration shown in FIG. 3, the electrode portion 12b and the nozzle 12 are integrated, but the electrode portion 12b may be separated from the nozzle 12 as shown in FIG. That is, the discharge / discharge unit may be composed of two members. In FIG. 4, the electrode portion 12b may have an annular structure in which the hydrogen-containing gas passes through the inside, or a mesh-like structure in which the hydrogen-containing gas passes through the gap.

In the configurations shown in FIGS. 1, 3 and 4, by arranging the electrode portion 12b on the flow path of the hydrogen-containing gas, it is possible to efficiently generate glow discharge. However, the present invention is not limited to these, and as shown in FIG. 5, the electrode portion 12b and the nozzle 12 may be arranged in different directions, and the electrode portion 12b may be separated from the flow path of the hydrogen-containing gas.

Next, the sample analysis method according to the embodiment of the present invention will be described by taking the configuration shown in FIG. 1 as an example. First, as shown in FIG. 1, the sample 11 is placed in the sample chamber 10 in a state where stress can be applied by the stress loading portion 15. Then, the insides of the sample chamber 10, the intermediate chamber 20, and the electron gun chamber 30 are maintained in a state of high vacuum degree. The degree of vacuum at this time is preferably ^{10-9 to 1} Pa.

After that, a hydrogen-containing gas is sprayed from the discharge portion 12a of the nozzle 12 onto the surface 11a of the sample 11, and a voltage is further applied by a power source to generate a glow discharge between the surface 11a and the nozzle 12. As a result, plasma is generated, and hydrogen in the hydrogen-containing gas sprayed on the surface 11a is ionized into hydrogen ions. Then, the hydrogen ions in the plasma are electrically attracted to the surface 11a and are efficiently introduced into the sample. In order to introduce sufficient hydrogen into the sample, the hydrogen concentration in the hydrogen-containing gas is preferably 5% by volume or more, more preferably 20% by volume or more.

Next, an electron beam is incident on the surface 11a. Then, the surface shape, crystal orientation, element distribution, etc. of the sample 11 are analyzed by detecting one or more selected from the electrons and X-rays emitted from the surface 11a. For example, by analyzing the surface shape, it is possible to analyze the origin of hydrogen embrittlement cracks, the propagation path, and the like. Further, by analyzing the crystal orientation, the effects of strain, crystal structure, etc. on hydrogen embrittlement can be analyzed.

Subsequently, stress is applied to the sample 11. The stress loading method is not particularly limited as described above. Hydrogen is introduced into the sample from the surface 11a, stress is further applied while the electron beam is incident on the surface 11a, and the sample surface is analyzed to determine the presence or absence of cracks, the crack generation starting point, and the propagation path. Etc. can be evaluated. Further, it is also possible to obtain the fracture toughness value or the like from the applied stress value.

In the above example, the electron beam is incident after the glow discharge is generated, but the glow discharge may be generated in the state where the electron beam is incident. Further, the glow discharge may be stopped in the middle of the surface analysis, or the surface analysis and the glow discharge may be alternately performed. It should be noted that backscattered electrons and the like can be detected during glow discharge, but secondary electrons with low energy cannot be detected. Therefore, when it is desired to observe the secondary electron image, it is necessary to suspend the glow discharge at the time of detection. When the glow discharge is stopped, the introduced hydrogen is released. Therefore, in order to suppress the release of hydrogen as much as possible, it is preferable to keep the sample at a low temperature.

Further, in the above example, although hydrogen is introduced into the sample and then stress is applied, hydrogen may be introduced after applying stress, or they may be performed at the same time. The stress may be fluctuating stress, cyclic stress or constant stress. For example, hydrogen may be introduced after applying a constant elastic stress, the stress may be continuously increased while introducing hydrogen, or hydrogen may be introduced while applying repeated elastic stress. May be good. Moreover, the load step may be omitted. In that case, it is not necessary to provide the stress loading portion 15 as in the configurations shown in FIGS. 4 and 5.

The flow rate of the hydrogen-containing gas supplied from the discharge unit 12a is preferably 1 mL / min or more and 100 mL / min or less. If this flow rate is too small, the pressure of the hydrogen-containing gas on the surface 11a becomes low, and there is a risk that glow discharge will not occur. On the other hand, if this flow rate is too large, the pressure of the hydrogen-containing gas on the surface 11a becomes too high, the surface 11a is heated by ion collision, an arc discharge occurs, and the elements constituting the sample 11 may evaporate. .. The flow rate of the hydrogen-containing gas is more preferably 5 mL / min or more and 80 mL / min or less.

In order to generate a glow discharge between the surface 11a of the sample 11 and the nozzle 12, the power supply voltage is preferably 100 V or more. In order to efficiently introduce hydrogen into the sample, the above power supply voltage is more preferably 200 V or more. On the other hand, if the power supply voltage is too high, the energy of hydrogen ions becomes high, so that the surface 11a is heated by the collision of hydrogen ions, an arc discharge occurs, and the elements constituting the sample 11 may evaporate. .. The above power supply voltage is more preferably 5 kV or less.

On the other hand, when the sample 11 is used as the cathode, the electron beam decelerates. Therefore, if the power supply voltage is too high, the electron beam cannot reach the surface 11a. Therefore, when the sample 11 is used as a cathode, the power supply voltage needs to be less than the accelerating voltage of the electron beam.

If the energy of the electron beam is too low, not only the probability of scattering the electron beam by hydrogen molecules increases, but also the probe diameter of the electron beam becomes large, which may make it impossible to obtain high-resolution analysis results. Therefore, the energy of the electron beam is preferably 200 eV or more, and more preferably 1 keV or more.

On the other hand, if the energy of the electron beam is too high, the number of electrons emitted from the surface 11a of the sample 11 may decrease. Therefore, the energy of the electron beam is preferably 50 keV or less, and more preferably 30 keV or less.

That is, the accelerating voltage of the electron beam is preferably 200 V or more, and more preferably 1 kV or more. The accelerating voltage is preferably 50 kV or less, and more preferably 30 kV or less.

If the irradiation current of the electron beam is low, the intensity of the electrons or X-rays emitted from the surface 11a of the sample 11 may be insufficient to detect. Therefore, the irradiation current of the electron beam is preferably 10 pA or more, and more preferably 100 pA or more.

On the other hand, if the irradiation current of the electron beam is too high, the probe diameter of the electron beam becomes large, and there is a risk that high-resolution analysis results cannot be obtained. Therefore, the irradiation current of the electron beam is preferably 1.5 μA or less, and more preferably 10 nA or less.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Martensitic steel (SCM435 steel) having the chemical composition shown in Table 1 and having a tensile strength of 1892 MPa was used as a sample. A test piece having the dimensions and shape shown in FIG. 6 was taken from this sample, and a wedge having the dimensions and shape shown in FIG. 7 was inserted into the notch to introduce a pre-crack. The wedge was held in a state of being inserted into the test piece, and a constant strain was applied to the test piece.

In this example, the test was carried out in an electron beam apparatus having the configuration shown in FIG. In addition, a glass window is provided in the sample chamber so that the test piece can be observed. As shown in FIG. 8, the injection shaft of the nozzle was perpendicular to the analysis surface of the test piece, and the material of the nozzle was stainless steel (SUS316 steel).

First, using the nozzle as an anode and the test piece as a cathode, a glow discharge was generated between the nozzle and the test piece, and it was investigated whether hydrogen was introduced into the test piece by hydrogen plasma. Within the range where the pressure in the sample chamber is 3 kPa or less, the opening cross-sectional area of the discharge part of the nozzle, the distance between the discharge part and the test piece, the flow rate of hydrogen-containing gas, and the power supply voltage are variously changed, and the nozzle and test are performed for 3 minutes. A voltage was applied between the pieces. Then, before and after the application of the voltage, the surface of the test piece was scanned with an electron beam in a vacuum to obtain a secondary electron image.

The energy of the electron beam was 15 keV, the irradiation current was 100 pA, and the electron beam was incident at an angle of 45 ° with respect to the normal direction of the surface of the test piece. When hydrogen is introduced into the test piece, hydrogen embrittlement occurs and cracks grow. The crack positions of these acquired secondary electron images were compared, and the presence or absence of hydrogen introduction was determined from the presence or absence of crack growth.

Table 2 shows the determination results of hydrogen introduction under various discharge conditions. The condition in which glow discharge is continuously generated and the crack grows by 20 μm or more due to the discharge is indicated by “◯”, and the condition in which the crack grows by 50 μm or more is particularly indicated by “⊚”. Further, the condition that the glow discharge is generated intermittently and the crack growth due to the discharge is less than 20 μm is indicated by “Δ”. Furthermore, although glow discharge occurred and cracks grew, arc discharge also occurred in a slight mixture, and the conditions under which evaporation was observed in a region of less than 5% of the sample surface on which hydrogen-containing gas was injected are indicated by "▲". ..

Further, FIG. 9 shows secondary electron images acquired before and after the application of the voltage under the discharge condition 9 in Table 2. As is clear from Table 2 and FIG. 9, when the opening cross-sectional area of the discharge part, the distance between the discharge part and the test piece, the flow rate of the hydrogen-containing gas, and the power supply voltage are properly set, between the nozzle and the test piece. It was confirmed that a glow discharge occurred and hydrogen was introduced into the test piece by hydrogen plasma. When the light emitting part of the glow discharge was visually inspected through the glass window of the sample chamber, it was also confirmed that the glow discharge was generated only between the nozzle and the test piece under all the discharge conditions in Table 2.

Next, the conditions of electron beam irradiation were investigated so that the surface of the test piece could be observed while introducing hydrogen. For this purpose, with the glow discharge generated under the discharge conditions 3 or 20 in Table 2, the electron beam energy and irradiation current are variously changed, the surface of the test piece is scanned with the electron beam, and the test piece is reflected every 30 seconds. An electronic image was acquired. The electron beam was incident on the surface of the test piece from an angle of 70 ° with respect to the normal direction.

Table 3 shows the measurement results. In the reflected electron image, the condition in which the crack can be observed with a resolution of 100 nm or more is indicated by “◯”, and the condition in which the crack can be observed with a high resolution of 20 nm or more is indicated by “⊚”. In addition, the condition that the crack was observable but the resolution was less than 100 nm and was slightly low is indicated by “Δ”. Furthermore, the condition that the crack was observable but the image was slightly noisy is indicated by "▲".

As is clear from Table 3, it was confirmed that the reflected electron image can be obtained while introducing hydrogen by appropriately setting the electron beam energy and the irradiation current.

According to the present invention, a glow discharge is generated only in the sample-electrode portion, and hydrogen is introduced into the sample by the generated hydrogen plasma, and the sample surface is analyzed with high resolution and over time by using an electron beam device. Becomes possible.

10. Sample room 11. Sample 11a. Surface 12. Nozzle 12a. Discharge unit 12b. Electrode part 13. Flow controller 14. Detector 15. Stress loading part 20. Intermediate chambers 20a, 20b. Small hole 30. Electron gun room 31. Electron gun 40. Vacuum exhaust unit 100. Electron beam device

Claims (12)

A method for analyzing a sample using an electron beam device that injects an electron beam onto the surface of the sample and detects one or more selected from electrons and X-rays emitted from the surface.
The step of incident the electron beam on the surface and
A discharge / discharge unit having a discharge portion and an electrode portion is provided inside the electron beam device, and a voltage is applied between the surface and the electrode portion while blowing a hydrogen-containing gas from the discharge portion to the surface. A step of applying and generating a glow discharge between the surface and the electrode portion is provided.
Sample analysis method. The discharge / discharge unit is made of a conductive material so as to function as the electrode portion, and includes a nozzle in which the discharge portion is formed.
The sample analysis method according to claim 1. The discharge / discharge unit includes a nozzle in which the discharge portion is formed and the electrode portion.
The sample analysis method according to claim 1. The electrode portion is provided on the nozzle.
The sample analysis method according to claim 3. The sample is a metallic material,
The sample analysis method according to any one of claims 1 to 4. In the step of generating the glow discharge, the magnitude of the voltage is set to 100 V or more and 5 kV or less.
The sample analysis method according to any one of claims 1 to 5. The opening cross-sectional area of the discharge portion is 1 μm ² or more and 0.01 mm ² or less.
The sample analysis method according to any one of claims 1 to 6. In the step of generating the glow discharge, the distance between the surface and the discharge portion is set to 10 μm or more and 2 cm or less.
The sample analysis method according to any one of claims 1 to 7. In the step of generating the glow discharge, the flow rate of the hydrogen-containing gas is set to 1 mL / min or more and 100 mL / min or less.
The sample analysis method according to any one of claims 1 to 8. In the step of incident the electron beam, the energy of the electron beam is set to 200 eV or more.
The sample analysis method according to any one of claims 1 to 9. In the step of incident the electron beam, the irradiation current of the electron beam is set to 10 pA or more.
The sample analysis method according to any one of claims 1 to 10. A step of applying stress to the sample is further provided.
The sample analysis method according to any one of claims 1 to 11.