JP6367618B2 - Light element analyzer and light element analysis method - Google Patents

Description

The present invention relates to a light element analysis apparatus and a light element analysis method.

Until now, elemental composition analysis has been performed with high spatial resolution using an analytical electron microscope or the like for material development. In this elemental composition analysis, heavy element analysis was mainly performed, and light element analysis was not performed. Light elements include hydrogen (H), helium (He), lithium (Li), beryllium (Be), boron (B), carbon (C), nitrogen (N), oxygen (O), and fluorine (F). This is because the detection of light elements was technically more difficult than the detection of heavy elements. Therefore, in recent years, research and development of light element analysis has begun.
Examples of techniques related to light element analysis include the following.

Non-Patent Document 2 relates to light element analysis by electron transition induced desorption (DIET) using an electron beam. DIET is a phenomenon that is generally observed when electronic excitation of the surface occurs, and is widely known. When particles such as light, atoms, electrons, and ions are irradiated on the surface of an object, the electronic state of the surface is excited and the bonds between atoms and molecules and the surface are broken. As a result, these substances constituting the surface are detached from the surface. This is a phenomenon of separation. DIET desorbs light element ion species from the surface. In addition to the desorbed light element ion species, ions emitted by sputtering with scattered helium ions or incident helium ions are hereinafter collectively referred to as secondary ions.

Non-Patent Document 3 shows an adsorption structure analysis by electron stimulated desorption ion angle distribution (ESDIAD). ESDIAD is the direction dependency that particles generally desorbed by DIET have. Since this direction dependency reflects the structure in the adsorption state before desorption, the adsorption state of the light element is analyzed by measuring this direction dependency.

Non-Patent Document 4 relates to light element analysis on the surface by time-of-flight analysis using secondary electrons and secondary ions.
Non-Patent Document 5 relates to light element analysis of a surface by time-of-flight analysis using an ion beam as an incident species and using secondary electrons and secondary ions.
Non-Patent Document 6 relates to DIET by ion beam and fluorine ion desorption.
Non-Patent Document 7 relates to secondary ion mass spectrometry used for analyzing the distribution of ion species constituting the surface by detecting secondary ions using an ion beam as an incident species.

Non-Patent Document 8 uses time-of-flight secondary ion mass spectrometry (TOF-SIMS) used for analyzing the distribution of ion species constituting the surface by detecting secondary ions using a pulsed ion beam as an incident species. ). In TOF-SIMS, distribution analysis of ion species constituting the surface is performed by injecting a pulsed ion beam and performing mass analysis of secondary ions by a time-of-flight method.

Non-Patent Document 9 relates to various microscopic methods such as secondary ion mass spectrometry used for analyzing the distribution of ion species constituting the surface by detecting secondary ions using an ion beam as an incident species. It is. It also describes surface analysis by DIET and ESDIAD.
Non-patent documents 10 and 11 disclose fluorine analysis by DIET.
Non-Patent Document 12 discloses DIET using light or metastable atoms.

Patent Document 1 relates to a light element analyzer using a neutron generator tube equipped with an α-ray detector and a light element detector capable of identifying the flight direction and energy of the light element.
Patent Document 2 relates to a light element analysis / evaluation apparatus in an insulator by low energy ion irradiation.
Using any of these advanced measurement techniques, it has not been easy to detect light elements with a high spatial resolution of 10 nm or less.

On the other hand, Non-Patent Document 1 relates to a helium ion microscope and its application. The helium ion microscope is an existing technology, and there is a helium ion beam microscope (product name: Orion PLUS, manufactured by Carl Zeiss) sold by Carl Zeiss. A helium ion beam of about 30 keV with a narrow diameter of 2 nm is incident on the sample surface, and by measuring secondary electrons and secondary ions, contrast resulting from surface morphology, structure and composition can be obtained with high spatial resolution. Yes.

JP 2007-71799 A JP 2006-46964 A

B. W. Ward et al. , J .; Vac. Sci. Technol. B 24 (2006) 2871. R. D. Ramsier and J.M. T.A. Yates, Jr. , Surf. Sci. Rep. 12 (1991) 243. P. A. Thiel and T. E. Madey, Surf. Sci. Rep. 7 (1987) 211. F. Busch et al. , Nucl. Instr. Meth. 171 (1980) 71. K. Yasuda et al. , Nucl. Instr. Meth. Phys. Res. B 269 (2011) 1019. R. Souda et al. Phys. Rev. B 15 (1999) 13854. Fujinori Fuji, Kenichiro Komaki, “Material Analysis and Modification by Ion Beam”, Uchida Otsutsuru, ISBN 4-7536-5033-2 C 3055, p. 113-144 Atsushi Murase, Toyota Central R & D Review 34 (1999) 11. M.M. Mundschau, Ultramicroscopy 36 (1991) 29 M.M. Batzill and K.M. J. et al. Snowdon, Appl. Phys. Lett. 77 (2000) 1955. L. Guo et al. , Key Engineering Materials, 562-565 (2013) 1069. T.A. Suzuki et al. Phys. Rev. Lett. 16 (2001) 3654.

An object of the present invention is to provide a light element analysis apparatus and a light element analysis method capable of easily detecting a light element with a high spatial resolution of 10 nm or less.

In view of the above circumstances, the present inventor made trial and error, and (1) even if the sample was irradiated with a continuous (CW) ion beam instead of a pulsed ion beam, based on electron transition induced desorption (DIET), Secondary electrons and secondary ions desorbed from the surface when the sample surface is electronically excited can be measured. (2) The time of flight (TOF) of secondary electrons is compared to the TOF of secondary (light element) ions. Since it is so short as to be negligible, a specific secondary ion peak is obtained at the position of a predetermined time-of-flight spectrum, triggered by secondary electrons desorbed from the surface when the sample surface is excited with electrons. (3) The inventors have come up with the idea that light elements can be detected with a high spatial resolution of 10 nm or less by irradiating a sample with a continuous ion beam that is very narrowly focused. In other words, a continuous ion beam is used and DIET is combined with TOF analysis. In fact, a continuous helium ion beam with a diameter of 2 nm or less and a kinetic energy of 30 keV is incident on the sample surface, and lithium ions desorbed from the surface by electron transition induced desorption are time-correlated with secondary electrons (flight) The present invention was completed by discovering that the lithium ion concentration can be detected with a high spatial resolution of 2 nm or less.
The present invention has the following configuration.

(1) A light element analyzer having a secondary ion detector having an ion detection surface, an electron detector having an electron detection surface, and a substrate holder on which a sample having an analysis target portion can be placed, the substrate The position of the holder can be moved horizontally, vertically, and rotationally with respect to the position of the secondary ion detector and the position of the electron detector, and the analysis target portion is made to be the ion detection surface and the electron detection surface. The shortest distance D from the analysis target part to the ion detection surface when the opposite arrangement is made, the _{secondary ion flight distance} is 12 mm or more and 300 mm or less, and from the analysis target part The shortest distance D to the electron detection surface D The _{secondary electron flight distance} is 2 mm or more and 100 mm or less.

(2) The light element analyzer according to (1), wherein the secondary ion detector has a substantially plate shape.
(3) The light element analyzer according to (2), wherein a beam passage hole is provided in the secondary ion detector so as to communicate one side and the other side.
(4) The secondary ion detector has a substantially hemispherical dome shape, and has a substantially hemispherical outer shape with a substantially hemispherical recess, and a beam passage hole so that the outer surface side and the inner surface side communicate with each other. And the ion detection surface is provided on the inner wall surface of the recess.

(5) A light element analysis method using an ion beam microscope, in which a sample is placed on a substrate holder provided in a lens barrel of the ion beam microscope, and the position of the substrate holder is moved horizontally, vertically and rotationally. The shortest distance D from the analysis target portion of the sample to the ion detection surface of the secondary ion detector after the ion detection surface and the electron detection surface are arranged opposite to each other in the sample analysis target portion D _{secondary ion flight A distance} between 12 mm and 300 mm and the shortest distance D from the analysis target part to the electron detection surface of the electron detector; a _{secondary electron flight distance} between 2 mm and 100 mm; A step of irradiating the analysis target portion with an ion beam emitted from an ion beam source; a step of detecting electrons emitted from the analysis target portion on the electron detection surface; Light element analysis method characterized by comprising the steps of: detecting secondary ions emitted from the analysis unit in the ion detection surface.

(6) Calculating the amount of light elements in the analysis target part by measuring ion intensity after the passage of secondary ion flight time according to each light element from the time when electrons are first detected on the electron detection surface. (4) The light element analysis method according to (5).
(7) The light element analysis method according to (6), wherein the light intensity of the linear region is calculated by scanning the ion beam in one direction while detecting the ion intensity.
(8) The light element amount described in (6) is calculated by scanning the ion beam in one direction and a direction perpendicular thereto while detecting the ion intensity. Elemental analysis method.

A light element analyzer of the present invention includes a secondary ion detector having an ion detection surface, an electron detector having an electron detection surface, and a substrate holder on which a sample having an analysis target portion can be placed. The position of the substrate holder can be moved horizontally, vertically, and rotationally with respect to the position of the secondary ion detector and the position of the electron detector, and the analysis target portion is detected by the ion detection. A shortest distance D _{secondary ion flight distance} from the analysis target part to the ion detection surface is 12 mm or more and 300 mm or less when the surface and the electron detection surface are arranged to face each other, and since configurations minimum distance D _{2-electron flight distance} from the analyzed portion to the electron detection surface and wherein the at 2mm or more than 100mm, less high spatial resolution 10nm Light elements can be easily detected.

The light element analysis method of the present invention is a light element analysis method using an ion beam microscope, in which a sample is placed on a substrate holder provided in a lens barrel of the ion beam microscope, and the position of the substrate holder is set horizontally. Vertically and rotationally moved, the analysis target part of the sample is placed in the shortest distance from the analysis target part of the sample to the ion detection surface of the secondary ion detector after the ion detection surface and the electron detection surface are arranged to face each other. the distance D _{2 ion flight distance} and 12mm or 300mm or less, and a step of the shortest distance D _{2-electron flight distance} to the electron detection surface of the electron detector with 2mm or more than 100mm from the analysis target part, a reduced pressure atmosphere The step of irradiating the analysis target portion with an ion beam emitted from an ion beam source of an ion beam microscope, and the electrons detected from the analysis target portion to the electron detection surface A step of detecting, the step of detecting the secondary ions emitted from the analyte portion at the ion detector surface, since the configuration having a light element can be easily detected by the following high spatial resolution 10 nm.

It is a figure explaining an example of the light element analyzer which is embodiment of this invention, Comprising: It is a perspective view (a) and sectional drawing (b). It is a perspective view explaining another example of the light element analyzer which is embodiment of this invention. It is a perspective view explaining another example of the light element analyzer which is embodiment of this invention. It is the cross-sectional schematic which shows the light element analyzer used in the present Example. It is a time-of-flight spectrum of each sample of MgLi, LiCoO ₂ , Si, and Ta. It is a secondary electron image of _{LiCoO 2 (800nm) / Nb-} SrTiO 3 samples. It is a graph which shows the lithium distribution analysis result obtained along the white line position of the secondary electron image shown in FIG.

(Light element analyzer)
(First embodiment of the present invention)
First, an example of a light element analyzer that is an embodiment of the present invention will be described.
FIG. 1 is a view for explaining an example of a light element analyzer according to an embodiment of the present invention, and is a perspective view (a) and a sectional view (b).
As shown in FIGS. 1A and 1B, a light element analyzer 11 according to an embodiment of the present invention includes a secondary ion detector 23 having an ion detection surface 23a and an electron detection having an electron detection surface 24a. And a substrate holder 26 on which a sample 25 having an analysis target portion 25a can be placed.

The light element analyzer 11 is an apparatus that is arranged in a lens barrel of an ion beam microscope using an apparatus in the ion beam microscope.
The light element analyzer 11 is arranged on the tip side of the ion microscope tube tip 22.

The ion beam source 21 and the ion so that the linear direction connecting the ion beam source 21 and the analysis target portion 25a passes through the hole 22c of the ion microscope tube tip 22 and the beam passage hole 23c of the secondary ion detector 23. The microscope tube tip 22 and the light element analyzer 11 are arranged.

The secondary ion detector 23 has a substantially plate shape that is annular in plan view. Further, a beam passage hole 23c is provided so as to communicate the one surface side and the other surface side, and an ion detection surface 23a is provided on the one surface side. However, the present invention is not limited to this configuration. For example, the secondary ion detector 23 may be configured without the beam passage hole 23c.

The position of the substrate holder 26 can be moved horizontally, vertically and rotationally with respect to the position of the secondary ion detector 23 and the position of the electron detector 24. Thereby, the analysis target part 25a of the sample 25 can be arranged toward the ion beam source 21.
Thereby, the sample can be irradiated with the ion beam emitted from the ion beam source 21 arranged on the other end side of the ion microscope tube tip 22.

The analysis target portion 25a can be disposed to face the beam passage hole 23c, the ion detection surface 23a, and the electron detection surface 24a. Thereby, ion beam irradiation, secondary ion detection, and electron detection can be performed on the analysis target portion 25a.

When the opposing arrangement is made, the shortest distance D _{secondary ion flight distance} from the analysis target portion 25a to the ion detection surface 23a is 12 mm or more and 300 mm or less. Thereby, secondary ions can be detected efficiently. When the distance is less than 12 mm, secondary ions reach the ion detection surface 23a in a short time, and therefore secondary ion species cannot be identified by the time-of-flight method. In the case of more than 300 mm, the number of secondary ions radiated to other than the ion detection surface 23a is increased, sensitivity is lowered, and detection efficiency is lowered. For this reason, it is more preferable to set it to 15 mm or more and 30 mm or less.

Wherein when the opposed, minimum distance D _{2-electron flight distance} from the analysis unit 25a to the electron detection surface is a 2mm or less than 100mm. Thereby, secondary electrons can be detected efficiently. If it is less than 2 mm, the secondary electron detector and the secondary ion detector interfere with each other, so that secondary electrons cannot be detected. In the case of more than 100 mm, the number of secondary electrons radiated to other than the electron detection surface 24a is increased, sensitivity is lowered, and detection efficiency is lowered.

(Second embodiment of the present invention)
Next, another example of the light element analyzer which is an embodiment of the present invention will be described.
FIG. 2 is a perspective view for explaining another example of the light element analyzer according to the embodiment of the present invention.
As shown in FIG. 2, the light element analyzer 12 according to the embodiment of the present invention has the same configuration as that of the first embodiment except that the secondary ion detector 33 has a substantially hemispherical dome shape. Yes.
The secondary ion detector 33 has a substantially hemispherical dome shape in which a substantially hemispherical outer portion 33b is provided with a substantially hemispherical recess 33c. An ion detection surface 33a is provided on the inner wall surface of the recess 33c. With this configuration, the secondary ions can be detected without fail.

A beam passage hole 33d is provided so as to communicate the outer surface side and the inner surface side. Thereby, an ion beam can be irradiated to the analysis object part 25a.

Furthermore, another beam passage hole 33e is provided so as to communicate the outer surface side and the inner surface side. Thereby, secondary electrons can be detected by the electron detection surface 24a.

(Third embodiment of the present invention)
Next, still another example of the light element analyzer which is an embodiment of the present invention will be described.
FIG. 3 is a perspective view illustrating still another example of the light element analyzer according to the embodiment of the present invention.
As shown in FIG. 3, in the light element analyzer 13 according to the embodiment of the present invention, the secondary ion detector 43 has a substantially disk shape, and is arranged apart from the ion beam passing direction. The configuration is the same as that of the first embodiment.
The secondary ion detector 43 is provided with a substantially circular ion detection surface 43a. Since the ion detection surface 43a is arranged to face the analysis target portion 25a, secondary ions can be detected.

Since the secondary ion detector 43 is arranged away from the ion beam passage direction, the ion beam can be irradiated to the analysis target portion 25a.

(Light element analysis method)
(Light element analysis of dotted areas)
Next, a light element analysis method according to an embodiment of the present invention will be described using the light element analysis apparatus 11 according to the first embodiment of the present invention.
A light element analysis method according to an embodiment of the present invention is a light element analysis method using an ion beam microscope, which includes a sample placement step S1, an ion beam irradiation step S2, an electron detection step S3, and secondary ion detection. Step S4.

(Sample placement step S1)
First, the sample 25 is placed on the substrate holder 26 provided in the lens barrel of the ion beam microscope.
Next, the position of the substrate holder 26 is moved horizontally, vertically, and rotationally so that the analysis target portion 25a of the sample 25 is disposed so that the ion detection surface 23a and the electron detection surface 24a face each other. At this time, the substrate holder 26 may be arranged after the inside of the lens barrel is depressurized.
Then, the shortest distance D _{2 ion flight distance} from the analysis portion 25a of the sample 25 to the ion detection surface 23a of the secondary ion detector 23 and 12mm above 300mm or less, and the electron detector from the analysis unit 25a 24 the shortest distance D _{2-electron flight distance} to the electron detection surface 24a and 2mm or less than 100mm.

(Ion beam irradiation step S2)
Next, the ion beam radiated from the ion beam source 21 of the ion beam microscope is passed through the beam passage hole 23c and irradiated on the analysis target portion 25a in a reduced pressure atmosphere.
The ion beam is controlled by a voltage adjusting unit (not shown) between the ion beam source 21 and the ion microscope tube tip 22 to control the beam direction.

As the incident species of the ion beam emitted from the ion beam source 21, various atomic and molecular ion species can be used. Since an apparatus of a helium ion beam microscope can be easily used, it is preferable to use a helium ion beam as incident ions. Furthermore, a material having a constant kinetic energy of about 30 keV and capable of narrowing down to a diameter of 2 nm or less is preferable. This allows light element analysis with high spatial resolution.

In addition, as long as the particles have a large kinetic energy of 100 eV or more, particles such as electrically neutral atoms can be detected by MCP. Since the kinetic energy of light element particles desorbed on the surface by DIET is 100 eV or less, electrically neutral desorbed particle species are not detected by MCP.

When the ion beam is irradiated onto the analysis target portion 25a of the sample, electronic excitation occurs on the surface of the sample 25, and DIET is observed. In DIET, first, surface electronic excitation occurs, and then hydrogen (H), helium (He), lithium (Li), beryllium (Be), boron (B), carbon (C), nitrogen (N), Light elements such as oxygen (O) and fluorine (F) are desorbed. Light element desorption occurs when the lifetime of surface excitation is longer than the time it takes for the desorbed particles to be sufficiently far from the surface.

Due to the generation of secondary electrons, the surface is excited electronically, and electron transition induced desorption (DIET), that is, light element surface desorption occurs simultaneously, and some of the light elements desorbing from the surface desorb as positive ions. .
Although DIET can occur inside a solid, it becomes atoms as a result of being neutralized in the process of escape to the surface, so that the desorbed ionic species detected are limited to those originating from the surface.

(Electron detection step S3)
Next, electrons emitted from the analysis target portion 25a of the sample 25 are detected by the electron detection surface 24a.

(Secondary ion detection step S4)
Secondary ions emitted from the analysis target portion 25a are detected by the ion detection surface 23a.

From the above detection results, secondary ion flight time (START time: 0 sec) corresponding to each light element from the time when electrons are first detected on the electron detection surface 24a using secondary electrons as triggers (start signals) ( By measuring the ionic strength after the lapse of Time of flight (TOF), the light element amount in the analysis target portion 25a can be calculated.
This is because the secondary ion flight time of each light element ion is fixed. For example, in the ion detector and sample arrangement shown in FIG. 4, the TOF _{Li ion} for 15.0 eV Li ⁺ _ions is about 660 ns, and the TOF _{H ion} for 13.4 eV H ⁺ _ions is About 270 ns.

Since electrons are 1000 times lighter than ions, the speed of secondary electrons is overwhelmingly faster than that of secondary ions. Therefore, the time of flight of secondary electrons between the surface of the sample 25 and the electron detector 24 is overwhelmingly short and negligible compared to the time until the secondary ions are emitted from the surface of the sample 25 and then arrive at the MCP. .

In addition, since the generation probability of secondary electrons is overwhelmingly higher than the light element ion generation probability by DIET, the secondary ions are used as a trigger, and signal processing using secondary electrons as a stop signal is effective. A time-of-flight spectrum of the next ion can be obtained (hereinafter referred to as pre-trigger measurement). However, the time-of-flight spectrum can be obtained by using secondary electrons as triggers.

As described above, a He ion beam having a diameter of 2 nm is irradiated, and the surface desorption ion concentration due to DIET generated by the ion beam irradiated on the sample surface of the sample 25 can be detected, and the ion concentration can be detected with a spatial resolution of 2 nm. Can be detected, and the light element analysis of the analysis target portion of the dotted region of the sample 25 can be performed.

(Light element analysis of linear region)
The light element analysis may be performed in the same manner as the light element analysis method described above except that the ion beam is scanned in one direction while detecting the ion intensity.
Thereby, the light element quantity of the linear area | region of the analysis object part 25a is computable.

(Light element analysis of planar area)
Light element analysis may be performed in the same manner as the light element analysis method described above, except that the ion beam is scanned in one direction and a direction perpendicular thereto while detecting the ion intensity.
Thereby, the light element quantity of the planar area | region of the analysis object part 25a is computable.

The light element analyzers 11, 12, and 13 according to the embodiment of the present invention include secondary ion detectors 23, 33, and 43 having ion detection surfaces 23a, 33a, and 43a, and an electron detector 24 having an electron detection surface 24a. And a substrate holder 26 on which the sample 25 having the analysis target portion 25a can be placed. The position of the substrate holder 26 is determined by the positions of the secondary ion detectors 23 and 33 and the electron detector 24. The analysis target portion 25a can be disposed opposite to the ion detection surfaces 23a, 33a, 43a and the electron detection surface 24a. Further, the shortest distance D _{secondary ion flight distance} from the analysis target part 25a to the ion detection surfaces 23a and 33a is 12 mm or more and 300 mm or less, and the analysis target part 25a The shortest distance D from the electron detection surface 24a to the electron detection surface 24a is a structure in which the _{secondary electron flight distance} is not less than 2 mm and not more than 100 mm.

In the light element analyzers 11 and 13 according to the embodiment of the present invention, since the secondary ion detectors 23 and 43 are substantially plate-shaped, light elements can be easily detected with a high spatial resolution of 10 nm or less.

Since the light element analyzer 11 according to the embodiment of the present invention has a configuration in which the beam passage hole 23c is provided in the secondary ion detector 23 so as to communicate the one surface side and the other surface side, a high spatial resolution of 10 nm or less. Can easily detect light elements.

In the light element analyzer 12 according to the embodiment of the present invention, the secondary ion detector 33 has a substantially hemispherical dome shape, and a substantially hemispherical outer shape portion 33b is provided with a substantially hemispherical concave portion 33c. Since the beam passage hole 33d is provided to communicate the outer surface side and the inner surface side, and the ion detection surface 33a is provided on the inner wall surface of the recess 33c, light elements can be easily detected with a high spatial resolution of 10 nm or less. .

A light element analysis method according to an embodiment of the present invention is a light element analysis method using an ion beam microscope, in which a sample 25 is arranged on a substrate holder 26 provided in a lens barrel of the ion beam microscope, and the substrate holder The position 26 is horizontally / vertically / rotated so that the analysis target portion 25a of the sample 25 is disposed opposite to the ion detection surface 23a and the electron detection surface 24a, and then the secondary ion detection is performed from the analysis target portion 25a of the sample 25. The shortest distance D _{secondary ion flight distance} to the ion detection surface 23a of the detector 23 is set to 12 mm or more and 300 mm or less, and the shortest distance D _{secondary electron flight distance} from the analysis target portion 25a to the electron detection surface 24a of the electron detector 24 And irradiating the portion to be analyzed with an ion beam emitted from an ion beam source of an ion beam microscope in a reduced pressure atmosphere. A step of detecting electrons radiated from the analysis target portion on the electron detection surface, and a step of detecting secondary ions radiated from the analysis target portion on the ion detection surface. Light elements can be easily detected with a high spatial resolution of 10 nm or less.

The light element analysis method according to the embodiment of the present invention measures the ion intensity after the lapse of the secondary ion flight time according to each light element from the time when electrons are first detected on the electron detection surface 24a, and the analysis target portion. Since the light element amount is calculated at 25a, the light element can be easily detected with a high spatial resolution of 10 nm or less.

The light element analysis method according to an embodiment of the present invention is configured to calculate the amount of light elements in a linear region by scanning the ion beam in one direction while detecting the ion intensity. Light elements can be easily detected with spatial resolution.

The light element analysis method according to an embodiment of the present invention is configured to calculate the amount of light elements in a planar region by scanning the ion beam in one direction and a direction perpendicular thereto while detecting the ion intensity. Therefore, light elements can be easily detected with a high spatial resolution of 10 nm or less.

The light element analysis apparatus and the light element analysis method according to the embodiment of the present invention are not limited to the above embodiment, and can be implemented with various modifications within the scope of the technical idea of the present invention. Specific examples of this embodiment are shown in the following examples. However, the present invention is not limited to these examples.

Example 1
Light element analysis was performed by the following time-of-flight analysis method.
FIG. 4 is a schematic cross-sectional view showing the light element analyzer used in this example.
First, this light element analyzer was installed in a lens barrel of a Carl Zeiss helium ion microscope (Orion PLUS) installed on the NIMS nanotechnology platform.

As a secondary ion detector (microchannel plate (MCP)), a ring-shaped detector having a central hole was used, and a plate-like MgLi sample was placed on a substrate holder (not shown).
In addition, an electron detector (not shown) was disposed in the vicinity of the secondary ion detector.

After the inside of the lens barrel is evacuated to an ultra-high vacuum, the position of the substrate holder is manipulated to set the facing distance between the sample surface of the sample and the ion detection surface of the secondary ion detector (microchannel plate (MCP)) to 12 .9 mm, the facing distance (working distance) between the sample surface and the lens barrel tip was 18 mm, the radius of the inner circle of the ring-shaped ion detection surface was adjusted to 2.25 mm, and the radius of the outer circle was adjusted to 5.75 mm. .

Next, a helium ion beam controlled to a constant kinetic energy of about 30 keV and narrowed to a diameter of 2 nm or less was generated.
Next, an appropriate voltage was selectively input between the internal input and the external input, and the irradiation position of the helium ion beam was controlled to a desired position on the sample surface and irradiated.

Next, the output of a pulse signal of +10 V or less having a half width of about 250 ns was confirmed by a digital oscilloscope connected to an electron detector, and the generated secondary electrons were confirmed.

Next, the output of another pulse signal was confirmed with a digital oscilloscope connected to the secondary ion detector, and secondary ions emitted between the trajectory A and the trajectory B from the sample toward the MCP were confirmed.

Next, pulse signals of secondary electrons and secondary ions are input to one of the digital oscilloscopes, triggered at the rising edge of the secondary ion pulse, the secondary electron pulse signals are integrated, and emitted simultaneously from the surface. The time correlation between secondary ions and secondary electrons was investigated. And the mass of the secondary ion was analyzed from the known flight distance of each light element.

(Example 2)
The mass of the secondary ions was analyzed in the same manner as in Example 1 except that the sample was LiCoO ₂ .

(Example 3)
The mass of the secondary ions was analyzed in the same manner as in Example 1 except that the sample was Si.

Example 4
The mass of secondary ions was analyzed in the same manner as in Example 1 except that the sample was Ta.

FIG. 5 is a time-of-flight spectrum of each sample of MgLi, LiCoO ₂ , Si, and Ta.
The vertical axis represents the intensity of secondary ions (arbitrary unit), and the horizontal axis represents the flight time (ns). TOF is related to the time-of-flight difference Δt between secondary electrons and secondary ions, and TOF = k−Δt (k is a constant determined by the apparatus configuration).

A clear lithium ion peak was detected in MgLi and LiCoO ₂ containing lithium. Lithium ions were well separated from other peaks. The intensity of the lithium ion peak was measured as a function of the irradiation position of the helium ion beam, and the distribution of lithium on the sample surface could be analyzed with high spatial resolution.

On the other hand, no lithium ion peak was detected in Si or Ta containing no lithium. In the sample containing no lithium (Si and Ta), a peak due to protons (hydrogen positive ions) appeared at about 2500 ns.

Time-of-flight spectrum peak due to scattering particles (helium ions and neutralized helium atoms), proton time-of-flight spectrum peak due to DIET, and time-of-flight spectrum peak of lithium ion due to DIET Was detected. That is, the order of arrival at the secondary ion detector was from the earlier to the order of scattering particles, protons, and lithium ions. In this measurement, a secondary ion is used as a trigger, so that the longer the flight time, the faster the ions.

(Example 5)
First, a portion of a plate-like Nb 0.5% -SrTiO ₃ sample having a side of 10 mm square is masked with a metal wire, LiCoO ₂ is deposited on the exposed portion, and a LiCoO ₂ (800 nm) / Nb—SrTiO ₃ sample is obtained. Produced.

Next, a secondary electron image of the border portion between the vapor deposition part and the non-vapor deposition part of the LiCoO ₂ (800 nm) /Nb0.5%-SrTiO ₃ sample was measured by scanning the helium ion beam and measuring the secondary electron intensity. did.
FIG. 6 is a secondary electron image of a LiCoO ₂ (800 nm) / Nb 0.5% -SrTiO ₃ sample. The black upper right region with poor contrast is a portion where Nb 0.5% -SrTiO ₃ is masked with a metal wire during deposition of LiCoO ₂ , and LiCoO ₂ was not deposited in this region. On the other hand, LiCoO ₂ was deposited on the lower left portion where the black and white contrast appeared.

Next, a helium ion beam was scanned along the white line position of the secondary electron image shown in FIG. 6 to perform TOF measurement.
FIG. 7 is a graph showing the lithium distribution analysis result obtained along the white line position of the secondary electron image shown in FIG. FIG. 7 is obtained by dividing the white line in FIG. 6 into 80, obtaining flight time spectra in order, finally obtaining the integrated intensity of the lithium ion peak in each spectrum, and plotting it as a function of the beam irradiation position. One pixel corresponds to 350 nm, and the measurement time at each pixel is 10 seconds.

In the region where no LiCoO ₂ was deposited, almost no lithium ion signal was observed. On the other hand, a lithium ion signal was observed in the region where LiCoO ₂ was deposited. In the deposited area, the signal intensity of lithium ions varied greatly depending on the location. That is, the distribution of lithium was not uniform.

The light element analysis apparatus and the light element analysis method of the present invention have a configuration in which a continuous ion beam is used and a combination of DIET and TOF analysis, and light elements can be easily detected with high spatial resolution of 10 nm or less. It can be widely applied to the distribution analysis of light elements such as, and can be used in the light element analysis industry. Further, it may be used in the light element analyzer industry, the fuel cell industry using light elements, the secondary battery industry, and the like.

DESCRIPTION OF SYMBOLS 11, 12, 13 ... Light element analyzer, 21 ... Ion beam source, 22 ... Ion microscope tube tip, 22c ... Hole, 23 ... Secondary ion detector (MCP), 23a ... Ion detection surface, 23c ... Beam passage Hole: 24 ... Electron detector, 24 ... Electron detection surface, 25 ... Sample, 25a ... Analysis target part, 26 ... Substrate holder, 33 ... Secondary ion detector (MCP), 33a ... Ion detection surface, 33b ... External part , 33c ... concave portion, 33d, 33e ... beam passage hole, 43 ... secondary ion detector (MCP), 43a ... ion detection surface.

Claims (7)

An ion beam source, a light element analyzer having a secondary ion detector, an electron detector with an electron detection surface, and a sample can be arranged a substrate holder having an analyte portion having ion-detection surface ,
The ion beam source irradiates the analysis target part with a continuous (CW) ion beam,
The position of the substrate holder can be horizontally / vertically / rotatably moved with respect to the position of the secondary ion detector and the position of the electron detector,
The analysis target portion can be disposed opposite to the ion detection surface and the electron detection surface,
When arranged oppositely, the shortest distance D from the analysis target part to the ion detection surface is a _{secondary ion flight distance} of 12 mm to 300 mm, and the shortest distance D from the analysis target part to the electron detection surface _{The secondary electron flight distance} is 2 mm or more and 100 mm or less ,
By measuring the ion intensity after the time of secondary ion flight time (TOF) corresponding to each light element from the time when electrons were first detected on the electron detection surface, the amount of light elements in the analysis target portion light element analysis device comprising a calculation child a.   The light element analyzer according to claim 1, wherein the secondary ion detector has a substantially plate shape.   3. The light element analyzer according to claim 2, wherein a beam passage hole is provided in the secondary ion detector so as to communicate one surface side with the other surface side.   The secondary ion detector has a substantially hemispherical dome shape, and has a substantially hemispherical outer shape with a substantially hemispherical recess, and a beam passage hole is provided so as to communicate the outer surface side and the inner surface side. The light element analyzer according to claim 1, wherein an ion detection surface is provided on an inner wall surface of the recess. A light element analysis method using an ion beam microscope,
A sample is placed on a substrate holder provided in a lens barrel of an ion beam microscope, and the position of the substrate holder is moved horizontally, vertically, and rotated, and the analysis target portion of the sample is moved to the ion detection surface and the electron detection. The shortest distance D from the analysis target portion of the sample to the ion detection surface of the secondary ion detector after being disposed opposite to the surface is set to a _{secondary ion flight distance} of 12 mm or more and 300 mm or less, and electron detection is performed from the analysis target portion. The shortest distance D to the electron detection surface of the instrument, the step of making the _{secondary electron flight distance} 2 mm or more and 100 mm or less,
A reduced-pressure atmosphere, continuously radiated from the ion beam source of an ion beam microscope (DW) Lee Onbimu, irradiating the analyte portion,
Detecting the electrons emitted from the analysis target portion on the electron detection surface;
Detecting secondary ions emitted from the analysis target portion on the ion detection surface;
Measuring the ion intensity after the lapse of the secondary ion flight time according to each light element from the time when electrons are first detected on the electron detection surface, and calculating the amount of light element in the analysis target portion. A light element analysis method characterized by the above. The light element analysis method according to claim 5 , wherein the light element amount in the linear region is calculated by scanning the ion beam in one direction while detecting the ion intensity. 6. The light element analysis according to claim 5, wherein the amount of light elements in the planar region is calculated by scanning the ion beam in one direction and a direction perpendicular thereto while detecting the ion intensity. Method.