JP2017101971A - Element identification device, element identification program, and element identification method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an element identification device capable of identifying an element in a short time.SOLUTION: The element identification device includes: a calculation part that makes association an atom position in an image of scanning transmission electron microscope with a plurality of groups 52 and 54 based on a signal strength corresponding to the atom in the scanning transmission electron microscope image, calculates shortest routes 63 and 65 each of which passes all the atom positions in each of the plurality of groups, and replaces a part of the atom positions among the plurality of groups on the basis of the calculation result; and an element identification part that, after the calculation part has replaced a part of the atom position, identifies the atom position in the plurality of groups as the respective elements.SELECTED DRAWING: Figure 14

Description

  The present invention relates to an element identification device, an element identification program, and an element identification method. For example, the present invention relates to an element identification device, an element identification program, and an element identification method for identifying an element from a scanning transmission electron microscope image.

  A transmission electron microscope (TEM) method is used, for example, when performing structural analysis or composition analysis at the atomic level of a material. Elemental element identification at the atomic level by using electron electron-loss spectroscopy (EELS) or energy dispersive X-ray spectroscopy (EDX) in combination with transmission electron microscopy (For example, Patent Documents 1 and 2).

JP 2001-124709 A JP 2001-153820 A

  In the method using both the TEM method and the EELS method or EDX method, analysis is performed for each atom. For this reason, the image capturing time becomes longer. As a result, for example, sample drift or damage due to electron beam irradiation occurs.

  An object of the present element identification device, element identification program, and element identification method is to enable element identification in a short time.

  Based on the signal intensity corresponding to the atoms in the scanning transmission electron microscope image, the atomic positions in the scanning transmission electron microscope image are made to correspond to a plurality of groups, respectively, and within each of the plurality of groups, the shortest route that passes through all the atom positions The calculation unit that calculates and replaces a part of the atomic positions between the plurality of groups based on the calculation result, and the atomic position in the plurality of groups is different after the calculation unit replaces a part of the atomic positions. An element identification device including an element identification unit for identifying an element is used.

  Based on the signal intensity corresponding to the atoms in the scanning transmission electron microscope image, the computer associates the atomic positions in the scanning transmission electron microscope image with a plurality of groups, and passes all the atomic positions in each of the plurality of groups. The shortest route is calculated, and based on the calculation result, a part of the atomic positions are replaced between the plurality of groups, and after a part of the atomic positions are replaced, the atomic positions in the plurality of groups are identified by different elements. An element identification program is used.

  An element identification method to be executed by a computer, the atomic positions in the scanning transmission electron microscope image corresponding to a plurality of groups based on the signal intensity corresponding to the atoms in the scanning transmission electron microscope image, and each of the plurality of groups And calculating a shortest route that passes through all the atom positions, replacing a part of the atom positions between the plurality of groups based on a calculation result, and replacing a part of the atom positions, and then replacing the atoms in the plurality of groups. An element identification method is used in which different elements are identified by different positions.

  According to this element identification device, element identification program, and element identification method, element identification can be performed in a short time.

FIG. 1 is a block diagram illustrating a system in which the element identification device according to the first embodiment is used. FIG. 2 is a schematic diagram of an electron microscope used in the first embodiment. FIG. 3 is a block diagram of a computer that functions as an element identification device according to the first embodiment. FIG. 4 is a functional block diagram of the element identification device according to the first embodiment. FIG. 5 is a flowchart illustrating processing performed by the computer according to the first embodiment. FIG. 6 is a flowchart showing the element identification process in the first embodiment. FIG. 7 is a diagram illustrating an example of an electron microscope image. FIG. 8 is a signal intensity histogram of FIG. FIG. 9 is a diagram showing a peak extraction image of region A in FIG. FIG. 10 is a histogram of the extracted peak intensity. FIG. 11 is a diagram showing a range that is difficult to identify in the histogram of FIG. FIG. 12A to FIG. 12C are diagrams showing atomic positions corresponding to the electron microscope image of FIG. FIG. 13A to FIG. 13D are diagrams (part 1) showing atomic positions included in each group. FIG. 14A to FIG. 14C are diagrams (part 2) showing the positions of atoms included in each group. FIG. 15A and FIG. 15B are diagrams (part 1) illustrating atomic positions corresponding to an electron microscope image in element identification processing. FIG. 16A and FIG. 16B are diagrams (part 2) illustrating atomic positions corresponding to an electron microscope image in element identification processing.

  Embodiments will be described with reference to the drawings.

  FIG. 1 is a block diagram illustrating a system in which the element identification device according to the first embodiment is used. As shown in FIG. 1, the system includes an element identification device 30, an electron microscope 32, an image input device 34, and an image output device 36. The element identification device 30 is, for example, a computer. The electron microscope 32 is a scanning transmission electron microscope. The image input device 34 is, for example, a computer. The image output device 36 is, for example, a display device such as a liquid crystal display device, a printing device such as a printer, or a computer having these.

  The electron microscope 32 captures an atomic level electron microscope image and outputs the electron microscope image to the element identification device 30. The image input device 34 outputs an electron microscope image taken by the electron microscope 32 in the past to the element identification device 30. It is sufficient that at least one of the electron microscope 32 and the image input device 34 is provided. The element identification device 30 identifies an element in the electron microscope image and outputs an element identification image to the image output device 36. The image output device 36 displays an element identification image. The element identification device 30, the electron microscope 32, the image input device 34, and the image output device 36 may be connected, for example, via the Internet. Input / output of images and the like between the element identification device 30, the electron microscope 32, the image input device 34, and the image output device 36 may be performed using a portable storage medium.

  FIG. 2 is a schematic diagram of an electron microscope used in the first embodiment. As shown in FIG. 2, a sample 40 is provided in the electron microscope 32. An electron beam 41 is irradiated on the upper surface of the sample 40. The electron beam 41 is converged to the atomic level on the upper surface of the sample 40. The electron beam 41 is scanned on the upper surface of the sample 40. The electrons transmitted through the sample 40 are classified into electrons 43 scattered at a high angle and electrons 45 scattered at a low angle. The electrons 43 scattered at a high angle are electrons diffused and diffused in the sample 40. The electrons 45 scattered at a low angle are electrons that are elastically scattered by the electrons in the sample 40. The annular dark field detector 42 detects the electrons 43. A circular bright field detector 44 detects electrons 45.

  The signal intensity output from the dark field detector 42 and the bright field detector 44 is formed as an image according to the position of the scanned electron beam 41. The image of the signal intensity output from the dark field detector 42 is a dark field image and is called a HAADF (High-angle Annular Dark Field) STEM image. An image of the signal intensity output from the bright field detector 44 is a bright field image and is called a HABF (High-angle Bright Field) STEM image. When the brightness of the HAADF STEM image is reversed, a HABF STEM image is obtained. The signal intensity at the atomic position in the HAADF STEM image is mainly derived from the atomic number. That is, the signal intensity increases as the atomic number increases. In Example 1, a HAADF STEM image is used.

  FIG. 3 is a block diagram of a computer that functions as an element identification device according to the first embodiment. The computer 10 includes a central processing unit (CPU) 11, a display device 12, an input device 13, an output device 14, a storage device 15, a storage medium drive 16, a communication interface 17, and an internal bus 18. The display device 12 includes a display panel such as a liquid crystal panel, for example, and displays commands or data. The input device 13 is a keyboard, a mouse, a touch panel, or the like, for example, and inputs commands or data. The output device 14 is a printer, for example, and outputs a command or data. The storage device 15 is, for example, a volatile memory such as a RAM (Random Access Memory), or a nonvolatile memory such as a flash memory or a hard disk, and stores a program, data during or after processing. The storage medium drive 16 is used when a program stored in the storage medium 19 is installed. The storage medium drive 16 acquires an electron microscope image from the storage medium 19 or stores an element identification image in the storage medium 19. The communication interface 17 acquires electron microscope image data from the electron microscope 32 or the image input device 34. Further, the communication interface 17 outputs an element identification image to the image output device 36. The internal bus 18 connects each device in the computer 10.

  A portable storage medium can be used as the storage medium 19 that can be read by the computer 10 storing the program. As the portable storage medium, for example, a CD-ROM (Compact Disc Read Only Memory) disc, a DVD (Digital Video Disc) disc, a Blu-ray disc, or a USB (Universal Serial Bus) memory can be used. As the storage medium 19, a flash memory or an HDD (Hard Disk Drive) may be used.

  FIG. 4 is a functional block diagram of the element identification device according to the first embodiment. The computer 10 functions as shown in FIG. 4 in cooperation with each member shown in FIG. 3 and software. The image acquisition unit 20 acquires an electron microscope image from the electron microscope 32 or the image input device 34. The computing unit 22 groups atomic positions based on the signal intensity corresponding to the atoms in the electron microscope image. Details will be described later. The element identifying unit 24 identifies atomic positions in the divided groups as different elements. Details will be described later. The image generation unit 26 generates and outputs an element identification image based on the element identification result.

  FIG. 5 is a flowchart illustrating processing performed by the computer according to the first embodiment. FIG. 6 is a flowchart showing the element identification process in the first embodiment. As shown in FIG. 5, the image acquisition unit 20 acquires an electron microscope image from the electron microscope 32 or the image input device 34 (step S10). For example, the CPU 11 acquires an electron microscope image via the communication interface 17. The computing unit 22 computes a peak extraction image from the electron microscope image (step S12). The calculation unit 22 calculates a histogram of peak intensity (step S14).

The processing in steps S10 to S14 will be described with reference to FIGS. FIG. 7 is a diagram showing an example of an electron microscope image, which is a dark field image (ie, HAADF STEM image) of a cross section of a sample obtained by growing LaCoO ₃ on SrTiO ₃ . As shown in FIG. 7, the left side is the domain 56 of SrTiO ₃ (strontium titanate) and the right side is the domain 58 of LaCoO ₃ (tantalum cobaltate) across the boundary 55 between the domains 56 and 58. The brightness (signal intensity) of the atomic image depends on the atomic number of the element.

  FIG. 8 is a histogram of the signal intensity of FIG. 7 and shows the number of pixels (pixels) in the electron microscope image with respect to the signal intensity (arbitrary coordinates). As shown in FIG. 8, there are two peaks in the histogram. In FIG. 8, signals of four elements of Ti (titanium), Sr (strontium), Co (cobalt), and La (lanthanum) are included. However, it is difficult to separate each element from the histogram of FIG. This is because there are signals in FIG. 7 other than the center position of the atoms.

  Therefore, in step S14, a pixel having a peak signal intensity of each atom is extracted from the electron microscope image of FIG. FIG. 9 is a diagram showing a peak extraction image of region A in FIG. As shown in FIG. 9, only the pixel of the peak signal in each atom (Ti and Sr) is white. That is, only the pixel of the peak signal in each atom (Ti and Sr) is extracted. The position of the extracted pixel in the electron microscope image is an atomic position, and the signal intensity of the extracted pixel is the intensity at which the signal intensity reaches a peak (that is, peak intensity). In the first embodiment, the pixel having the highest signal intensity is extracted for each atom. For example, the atomic position and peak intensity may be calculated by fitting assuming that the signal intensity is Gaussian in each atom.

  FIG. 10 is a histogram of the extracted peak intensity, and shows the number of pixels of the peak extracted image with respect to the peak intensity (arbitrary coordinates). As shown in FIG. 10, there are three peaks in the histogram. A peak with a low peak intensity corresponds to Ti, and a peak with a high peak intensity corresponds to La. However, the peak intensity peaks of Sr and Co overlap and cannot be separated.

  Returning to FIG. 5, the element identifying unit 24 identifies the element of each atom based on the peak intensity histogram (step S <b> 16). For example, in FIG. 10, three peaks are identified from each element. For example, the peak having the smallest peak intensity is identified as Ti having the smallest atomic number. The peak having the highest peak intensity is identified as La having the largest atomic number. Thereby, the atomic position included in the group 51 of FIG. 10 is identified as Ti, and the atomic position included in the group 53 is identified as La.

  Returning to FIG. 5, the calculation unit 22 determines whether there is a peak that is difficult to identify (step S <b> 18). For example, as illustrated in FIG. 10, when the number of constituent elements and the number of peaks in the peak intensity histogram are different, the calculation unit 22 determines that identification is difficult. When No, the process proceeds to step S24. When the result is Yes, the calculation unit 22 sets a range that is difficult to identify (step S20). FIG. 11 is a diagram showing a range that is difficult to identify in the histogram of FIG. As shown in FIG. 11, the histogram is the same as FIG. The range 50 is a range in which the peak intensities of Sr and Co overlap and it is difficult to identify elements from the histogram. Therefore, the calculation unit 22 sets the range 50 as a difficult-to-identify range.

  Returning to FIG. 5, the calculation unit 22 performs element identification processing (step S <b> 22). As shown in FIG. 6, the calculating part 22 divides | segments the identification difficulty range into a some group (step S30). As shown in FIG. 11, the range 50 is divided into two adjacent groups 52 and 54 that do not overlap each other.

  12 (a) to 12 (c) are diagrams showing atomic positions corresponding to the electron microscope image of FIG. 7, and have peak intensities included in the range 50 and the groups 52 and 54 shown in FIG. 11, respectively. It is a figure which shows the atomic position of a pixel. As shown in FIG. 12A, the atomic positions of the pixels having the peak intensity included in the range 50 are distributed throughout, and Sr and Co are not identified. As shown in FIG. 12 (b), atomic positions with small peak intensities included in the group 52 are mainly located in the domain 56, but some are located in the domain 58. As shown in FIG. 12 (c), the atomic position having a high peak intensity included in the group 54 is located in the domain 58, but there is also a region where the atomic position is not displayed in the domain 58. Thus, it can be seen that the elements cannot be identified by simply dividing the range 50 into the groups 52 and 54.

  Returning to FIG. 6, the computing unit 22 computes the shortest distance route of one-stroke writing passing through all the atom positions in each of the groups 52 and 54 (step S <b> 32). This problem is called the traveling salesman problem, and various solutions are known. In the first embodiment, a annealed (simulated annealing) method is used. The computing unit 22 determines whether there is a place where the interval between adjacent atomic positions on the route is longer than the nearest interatomic distance (step S34). If no, the process ends. When the result is Yes, the calculation unit 22 moves an atomic position longer than the closest interatomic distance to another group (step S36).

  The computing unit 22 determines whether there is an atomic position sandwiched by a route having a distance between adjacent atomic positions on the route that is longer than a certain distance (step S38). The fixed distance is, for example, twice the closest interatomic distance. When No, the process proceeds to step S42. When the result is Yes, the calculation unit 22 moves all the atomic positions sandwiched by this path to another group (step S40). The calculation unit 22 determines whether the arrangement is the same as the previous atomic position (step S42). When yes, the process ends. If no, the process returns to step S32.

  First, the flow excluding steps S38 and S40 will be described. FIG. 13A to FIG. 14C are diagrams showing atomic positions included in each group. FIG. 13A schematically shows, for example, atomic positions included in the range 50 of FIG. FIGS. 13B to 14C schematically show the positions of atoms included in the groups 52 and 54. Although the domains 56 and 58 may be unknown, the element 62 is included in the domain 56 and the element 64 is included in the domain 58. The boundary 55 is a boundary between the domains 56 and 58.

  As shown in FIG. 13A, six elements 62 are arranged in the domain 56, and six elements 64 are arranged in the domain 58. It can be seen that at the atomic positions included in the range 50, the elements 62 and 64 are not classified. As shown in FIG. 13B, the range 50 is divided into two groups 52 and 54 in step S30. Atomic position 64 a is included in group 52 and is not completely classified as domains 56 and 58. As shown in FIG. 13C, in step S32, the traveling salesman problem is solved in each of the groups 52 and 54, and the shortest distance routes 63 and 65 are calculated by a single stroke passing through all the atomic positions.

  As shown in FIG. 13D, there are paths 63a and 65a in which the distance between adjacent atomic positions on the routes 63 and 65 is longer than the closest interatomic distance in step S34. The paths 63a and 65a are unnatural as paths connecting adjacent atomic positions in the same domains 56 and 58. In this case, the atom positions 64a and 64b (circled atom positions) to which the paths 63a and 65a are connected may not belong to the original group. When one atomic position is sandwiched between the paths 63a as in the atomic position 64a, the sandwiched atomic position 64a is extracted. When the path 65a exists alone as in the path 65a, either one of both ends of the path 65a is extracted as the atomic position 64b depending on the scanning direction of the route 65.

  As shown in FIG. 14A, the atomic position 64a is moved to the group 54 and the atomic position 64b is moved to the group 52 in step S36. The atomic position 64 b is an atomic position that does not have to move to the group 52. However, in FIG. 13D, the atomic position 64 a is missing from the group 54, so the path 65 a is extracted, and as a result, the atomic position 64 b has moved to the group 52. As shown in FIG. 14B, the process returns to step S32, and the shortest distance routes 63 and 65 are calculated by a single stroke passing through all the atom positions. In step S <b> 34, a path 63 a in which the distance between adjacent atomic positions on the route 63 is longer than the closest interatomic distance exists. In group 54, there is no long path. In FIG. 14C, the atomic position 64b connected to the long path 63a is moved to the group 54. Thereby, the elements 62 and 64 can be classified into the domains 56 and 58, respectively. In step S42, since the same result is obtained even if the same calculation is repeated thereafter, the calculation is terminated. In this way, the elements can be identified by repeating steps S30 to S36.

  An example of calculation in which steps S32 to S42 are repeated with respect to FIGS. 12B and 12C will be described. FIG. 15A to FIG. 16B are diagrams showing atomic positions corresponding to an electron microscope image in element identification processing. In each figure, the left side corresponds to the group 52 and the right side corresponds to the group 54. The left side in each group 52 and 54 corresponds to the domain 56, and the right side corresponds to the domain 58. In an actual calculation, the domains 56 and 58 may be unknown, but the domains 56 and 58 will be used for easy understanding.

  FIG. 15A shows the result of solving the traveling salesman problem with respect to the atomic positions in FIGS. 12A and 12B. Routes 63 and 65 are set for the groups 52 and 54. In the group 52, many atomic positions on the route 63 remain in the domain 58. In the group 54, the atomic position on the route 65 remains in the domain 56. FIG. 15B shows the result of repeating steps S32 to S42 10 times. In the group 54, there is no atomic position on the route 65 in the domain 56 except near the boundary 55. However, in the group 52, many atomic positions on the route 63 remain in the domain 58.

  FIG. 16A shows the result of repeating steps S32 to S42 50 times. In the group 52, a block 67 of an atomic position on the route 63 exists in the domain 58. Both ends of the block 67 on the route 63 are connected to the domain 56 via a path 63b. In the path 63b, the distance between adjacent atomic positions on the route 63 is longer than twice the distance between the nearest atoms. Such a block 67 sandwiched between the paths 63 b is unnatural to belong to the same domain as the domain 56. In step S38, the calculation unit 22 determines Yes. In step S40, the calculation unit 22 moves the block 67 sandwiched by the path 63b to the group 54.

  As shown in FIG. 16 (b), when the block 67 is moved to the group 54, the groups 52 and 54 are classified into the atomic positions of the domains 56 and 58. After this, even if steps S32 to S42 are repeated, the result does not change and converges. Therefore, in step S42, the calculation unit 22 determines Yes. Even after convergence, the two arrangements may be repeated. For this reason, in step S42, it is determined whether or not it has converged by determining whether or not it has changed from the arrangement of atomic positions two times before in the loop of steps S32 to S42.

  Returning to FIG. 6, when the calculation unit 22 determines Yes in step S <b> 42, the process ends, and the process proceeds to step S <b> 24 in FIG. 5. The element identification unit 24 identifies the element for each of the groups 52 and 54 and generates an element identification image. Thereafter, the element identification image is output to the image output device 36 (step S24). For example, the atomic position in the group 52 is identified as Sr, and the atomic position in the group 54 is determined as Co. The atomic positions of Ti and La identified in step S16 are aligned, and an element identification image corresponding to the electron microscope is generated. For example, the element identification image is an image in which an atomic image of an electron microscope image is colored according to the type of element. The element identification image may be an image displaying an atomic image of only a specific element in the electron microscope image. For example, four images displaying atomic images respectively corresponding to Ti, Sr, Ca, and La may be generated as element identification images. Moreover, the element identification part 24 may produce | generate an element identification result as numerical data, without producing | generating an element identification image. Then exit.

  For example, when the element identification program and the element identification method of Example 1 are executed by a commercially available personal computer, an element having an atomic position of 1000 or more can be identified in about several seconds from an electron microscope image having one side of 512 pixels. On the other hand, when elements are identified with the same resolution using the EELS method, if the EELS analysis time per pixel is about 0.1 seconds, the element identification time for 512 pixels per side is about 7 hours. . Thus, in Example 1, element identification can be performed at an extremely high speed.

  As described above, the electron microscope image in which the element type and domain are known as shown in FIG. 7 has been described as an example. Even when there is no element composition and domain information in the electron microscope image (for example, when the crystal information of the sample is unknown), element identification is possible. For example, the user transmits an electron microscope image to the element identification device 30 via the Internet or the like without disclosing crystal information. The element identification device 30 automatically identifies the element and transmits the result to the image output device 36 of the user via the Internet or the like. Thus, the user can obtain an element identification image without disclosing any crystal information. Such a cloud service or the like can also be performed using the first embodiment.

  According to the first embodiment, as shown in step S30 of FIG. 6, the calculation unit 22 corresponds the atomic positions in the image to the plurality of groups 52 and 54 based on the signal intensity corresponding to the atoms in the scanning transmission electron microscope image, respectively. Let As in step S32, the shortest routes 63 and 65 passing through all the atom positions are calculated in each of the plurality of groups 52 and 54. As in steps S34 and S36, the computing unit 22 interchanges some of the atomic positions between the plurality of groups 52 and 54 based on the calculation result. As in steps S22 and S24 of FIG. 5, the element identifying unit 24 identifies the atomic positions in the plurality of groups 52 and 54 after replacement as different elements. Thereby, element identification time can be shortened compared with the method using TEM method, EELS method, or EDX method together. Thereby, the damage by the drift of a sample or electron beam irradiation can be suppressed, for example. Further, it is not necessary to use an expensive apparatus such as the EELS method or the EDX method.

  In Example 1, although the HAADF STEM image was demonstrated as an electron microscopic image, a HABF STEM image may be sufficient as an electron microscopic image. When the HABF STEM image is used as the electron microscope image, inversion processing such as multiplying the signal intensity by −1 is performed before step S12. In the electron microscope image, the signal intensity may be dependent on the atomic number.

  As in step S <b> 12 of FIG. 5, the calculation unit 22 associates the atomic positions in the electron microscope image with the plurality of groups 52 and 54 based on the intensity at which the signal intensity corresponding to the atoms peaks. Thereby, as shown in FIG. 10, the identification of the element by the signal intensity becomes easier. When element identification is possible using FIG. 8, the element identification processing may be performed from the signal intensity of FIG. 8 without extracting the peak intensity.

  As shown in step S30 of FIG. 6 and FIG. 11, the calculation unit 22 divides the signal intensity range 50 in which element identification is difficult into a plurality of ranges. The computing unit 22 associates atomic positions having signal intensities within a plurality of ranges with a plurality of groups 52 and 54, respectively. Thereby, the element in the range where element identification is difficult can be identified.

  Although the number of groups to be divided in step S30 in FIG. 6 is arbitrary, the number of the plurality of groups is preferably the same as the number of elements that are difficult to identify in the signal intensity range 50 where it is difficult to identify the elements. . Thereby, a group can be made to correspond to an element on a one-to-one basis.

  As in steps S34 and S36, the calculation unit 22 moves an atomic position where the distance between adjacent atomic positions on the shortest route is longer than a first distance (for example, the closest interatomic distance) to another group. When the distance between adjacent atom positions in the shortest route is longer than the distance between the nearest atoms, the group to which the atom position belongs may not be correct. Therefore, this atomic position is moved to another group. This facilitates element identification. The first distance may be equal to or greater than the nearest interatomic distance. When the first distance is more than twice the nearest interatomic distance, even if the group to which the atomic position belongs is not correct, the atomic position may not be moved to another group. Therefore, the first distance is preferably a constant distance that is equal to or greater than the nearest interatomic distance and shorter than twice the nearest interatomic distance. The closest interatomic distance may vary depending on the crystal orientation. For example, in the route 65 in the group 54 in FIG. 14B, the closest interatomic distance in the oblique direction may be larger than the closest interatomic distance in the horizontal direction and the vertical direction.

  In FIG. 16A, when steps S38 and S40 are not performed, steps S32 to S42 are repeated until convergence to FIG. 16B. Therefore, as in steps S38 and S40, the calculation unit 22 determines an atomic position sandwiched by a path in which the distance between adjacent atomic positions on the shortest route is longer than a second distance (for example, twice the distance between nearest atoms). Move to another group. As in the group 52 in FIG. 16A, the block 67 at the atomic position sandwiched by the path 63b in which the distance between adjacent atomic positions is longer than twice the distance between the nearest atoms may belong to an incorrect group. high. Therefore, the group is moved together with the block 67. Thereby, the calculation time can be shortened compared with the case where steps S38 and S40 are not performed. The second distance may be a certain distance that is at least twice the distance between the nearest atoms.

  In the groups 52 and 54, the element identification unit 24 repeats steps S32 to S42 in each of the groups 52 and 54, and identifies elements as elements when replacement of part of atomic positions is no longer performed as in step S42. Thereby, the element can be identified after the convergence of the calculation.

  As shown in FIG. 7, the electron microscope image includes a plurality of domains 56 and 58. In such a case, by identifying the element, the boundary 55 between the domains 56 and 58 can be determined as shown in FIG. Therefore, the domains 56 and 58 can be extracted.

  As in step S <b> 16 of FIG. 5, the element identification unit 24 identifies another element from a signal intensity other than the signal intensity range 50 in which it is difficult to identify the element. Thereby, another element can be easily identified.

  As in step S <b> 24 of FIG. 5, the image generation unit 26 generates an image that identifies the element corresponding to the electron microscope image based on the element identified by the element identification unit 24. Thereby, an element identification result can be expressed visually.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

In addition, the following additional notes are disclosed regarding the above description.
(Appendix 1) Based on the signal intensity corresponding to the atoms in the scanning transmission electron microscope image, the atomic positions in the scanning transmission electron microscope image are respectively associated with a plurality of groups, and all the atomic positions in each of the plurality of groups An arithmetic unit that calculates a shortest route to pass, and replaces part of the atomic positions between the plurality of groups based on the calculation result; and after the arithmetic unit replaces part of the atomic positions, the atoms in the plurality of groups An element identification device comprising: an element identification unit for identifying each position by a different element.
(Supplementary note 2) The supplementary note 1, wherein the calculation unit associates atomic positions in the scanning transmission electron microscope image with a plurality of groups based on the intensity at which the signal intensity corresponding to the atoms reaches a peak. Element identification device.
(Additional remark 3) The said calculating part divides | segments the range of the signal intensity | strength where it is difficult to identify an element into a some range, and signal intensity makes each atomic position in the said some range correspond to the said some group, respectively. The element identification device according to Supplementary Note 1 or 2.
(Supplementary note 4) The element identification device according to supplementary note 3, wherein the number of the plurality of groups is the same as the number of elements that are difficult to identify in a signal intensity range in which the elements are difficult to identify.
(Additional remark 5) The said calculating part moves the atomic position where the distance of the adjacent atomic position on the said shortest route is longer than 1st distance more than the nearest interatomic distance to another group from the additional remark 1 characterized by the above-mentioned. 5. The element identification device according to any one of 4.
(Additional remark 6) The said calculating part moves the atomic position on which the distance of the adjacent atomic position on the said shortest route is pinched | interposed by the path | route longer than 2nd distance more than twice the distance between nearest atoms to another group The element identification device according to supplementary note 5, wherein
(Additional remark 7) The said element identification part repeats the calculation which the said calculating part calculates the said shortest route in each of these groups, and replaces a part of atomic position between these groups, The element identification device according to any one of appendices 1 to 6, wherein when a part of the replacement is not performed, the atomic positions in the plurality of groups are identified by different elements.
(Supplementary note 8) The element identification device according to any one of supplementary notes 1 to 7, wherein the scanning transmission electron microscope image includes a plurality of domains.
(Supplementary note 9) The element identification device according to supplementary note 3 or 4, wherein the element identification unit identifies another element from a signal intensity outside a signal intensity range in which it is difficult to identify the element.
(Supplementary note 10) Any one of Supplementary notes 1 to 9, further comprising an image generation unit that generates an image that identifies the element corresponding to the scanning transmission electron microscope image based on the element identified by the element identification unit. An element identification device according to claim 1.
(Supplementary Note 11) A computer is caused to correspond to each atom position in the scanning transmission electron microscope image based on the signal intensity corresponding to the atom in the scanning transmission electron microscope image, and in each of the plurality of groups, an atom The shortest route that passes through all the positions is calculated, and based on the calculation result, a part of the atomic positions are replaced between the plurality of groups, and after a part of the atomic positions are replaced, the atomic positions in the plurality of groups are different from each other. An element identification program characterized by allowing an element to be identified.
(Supplementary note 12) An element identification method to be executed by a computer, wherein the atomic positions in the scanning transmission electron microscope image are respectively associated with a plurality of groups based on the signal intensity corresponding to the atoms in the scanning transmission electron microscope image, Within each of the plurality of groups, the shortest route that passes through all the atomic positions is calculated, and based on the calculation result, a part of the atomic positions is replaced between the plurality of groups, and after a part of the atomic positions are replaced, A method for identifying an element, characterized in that each atom position in a group is identified by a different element.

DESCRIPTION OF SYMBOLS 10 Computer 20 Image acquisition part 22 Operation part 24 Element identification part 26 Image generation part 30 Element identification apparatus 32 Electron microscope 34 Image input apparatus 36 Image output apparatus 50 Difficult-of-identification range 52, 54 Group 55 Boundary 56, 58 Domain 62, 64 Element 64a, 64b Atomic position 63, 65 Route 63a, 63b, 65a Route

Claims (10)

Based on the signal intensity corresponding to the atoms in the scanning transmission electron microscope image, the atomic positions in the scanning transmission electron microscope image are made to correspond to a plurality of groups, respectively, and within each of the plurality of groups, the shortest route that passes through all the atom positions A calculation unit that calculates and replaces part of atomic positions between the plurality of groups based on the calculation result;
After the arithmetic unit replaces a part of the atomic positions, an element identifying unit that identifies the atomic positions in the plurality of groups as different elements, and
An element identification device comprising:   2. The element identification according to claim 1, wherein the calculation unit associates each atomic position in the scanning transmission electron microscope image with a plurality of groups based on an intensity at which a signal intensity corresponding to the atom reaches a peak. apparatus.   The calculation unit divides a range of signal intensity where it is difficult to identify an element into a plurality of ranges, and the signal intensity corresponds to atomic positions in the plurality of ranges respectively corresponding to the plurality of groups. 3. The element identification device according to 1 or 2.   4. The element identification device according to claim 3, wherein the number of the plurality of groups is the same as the number of elements that are difficult to identify in a signal intensity range in which the elements are difficult to identify.   5. The calculation unit according to claim 1, wherein the calculation unit moves an atomic position having a distance between adjacent atomic positions on the shortest route that is longer than a first distance that is equal to or greater than the nearest interatomic distance to another group. An element identification device according to claim 1.   The arithmetic unit moves an atomic position sandwiched by a path longer than a second distance in which the distance between adjacent atomic positions on the shortest route is twice or more the closest interatomic distance to another group, The element identification device according to claim 5.   The element identification unit repeats an operation in which the calculation unit calculates the shortest route in each of the plurality of groups, and replaces part of the atomic positions between the plurality of groups, thereby replacing part of the atomic positions. 7. The element identification device according to claim 1, wherein when the operation is stopped, the atomic positions in the plurality of groups are identified as different elements.   The element identification apparatus according to claim 1, wherein the scanning transmission electron microscope image includes a plurality of domains. On the computer,
Based on the signal intensity corresponding to the atoms in the scanning transmission electron microscope image, the atomic positions in the scanning transmission electron microscope image correspond to a plurality of groups,
Within each of the plurality of groups, calculate the shortest route through all the atom positions,
Based on the calculation results, replace some of the atomic positions between the plurality of groups,
An element identification program, wherein after replacing a part of the atomic positions, the atomic positions in the plurality of groups are identified by different elements. An element identification method executed by a computer,
Based on the signal intensity corresponding to the atoms in the scanning transmission electron microscope image, the atomic positions in the scanning transmission electron microscope image correspond to a plurality of groups,
Within each of the plurality of groups, calculate the shortest route through all the atom positions,
Based on the calculation results, replace some of the atomic positions between the plurality of groups,
After exchanging a part of the atomic positions, the element identifying method includes identifying different atomic positions in the plurality of groups.

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