Analysis method using electron microscope, and electron microscope

An analysis method using an electron microscope, detects by a first electronography detector an electron beam transmitted through or scattered by a sample to detect an ADF image of the sample, detects by a second electronography detector the electron beam passing through the first electronography detector to detect an MABF image, adjusts a focal point of the electron beam to be located on the film of the sample to obtain first and second electronographies by the second and first electronography detectors, respectively, adjusts the focal point of the electron beam to be located on the substrate of the sample to obtain third and fourth electronographies by the second and first electronography detectors, respectively, aligns positions of the second and fourth electronographies based on the first and third electronographies, and after the aligning, subtracts the fourth electronography from the second electronography to obtain an image of the film.

FIELD

The embodiments discussed herein are related to an analysis method using electron microscope, and an electron microscope.

BACKGROUND

A TEM (Transmission Electron Microscope) and an STEM (Scanning Transmission Electron Microscope) are useful techniques for performing structural analysis and composition analysis at atomic levels of materials. However, the TEM acquires an image using an electron beam transmitted through a sample, and the structure in the acquired image reflects 2-dimensinoal symmetry. For this reason, there are demands to develop a method of acquiring a 3-dimensional tomogram using the TEM. Recently, development of a spherical aberration correcting apparatus enabled forming of an electromagnetic lens having a shallow DOF (Depth Of Field). Hence, by using the spherical aberration correcting apparatus and acquiring an image by varying a focal position, it is now possible to acquire the 3-dimensional tomogram. Actual observation examples using the spherical aberration correcting apparatus include pinpoint observation results of a boundary or a film deposited on a substrate surface reported in Japanese Laid-Open Patent Publication No. 2012-43563, and N. Shibata et al., “Atomic-scale imaging of individual dopant atoms in a buried interface”, Nature Materials, Vol. 8, August 2009, pp. 654-658, for example.

However, when acquiring the 3-dimensional tomogram using the TEM or the like, accurate positional relationship, and definite atomic deviation and distortion are required of the image that is acquired at each of a plurality of depth positions. For example, in the case of the sample in which a film made of a material having a composition different from that of a substrate is deposited on the substrate, it may be important to definitely know the relationship at the atomic level between the substrate and the film, and the atomic deviation and distortion of the film. However, according to a method proposed in Japanese Laid-Open Patent Publication No. 2012-43563, for example, the images at each of the substrate and the film are acquired by varying the focal position, and the sample moves (or drifts) at the atomic level while the focal position is varied. In a case in which the sample moves at the atomic level while the focal position is varied, it is difficult to detect the atomic deviation and distortion between the substrate and the film. In addition, because the film that is deposited on the substrate is thin, information of the substrate is included in the image of the film that is acquired, thereby making it difficult to detect the atomic deviation and distortion of the film deposited on the substrate.

SUMMARY

Accordingly, it is an object in one aspect of the embodiments to provide an analysis method using electron microscope, and an electron microscope, which can definitely detect the atomic deviation and distortion of the film that is deposited on the substrate.

According to one aspect of the embodiments, an analysis method uses an electron microscope including an electron source, a first electronography detector, and a second electronography detector, and includes accelerating and irradiating an electron beam emitted from the electron source on a sample so that a focal point of the electron beam is located on the sample, wherein the sample includes a substrate that includes fluorine or an element lighter than fluorine, and a film formed on a surface of the substrate; detecting, by the first electronography detector, the electron beam transmitted through or scattered by the sample, to detect an ADF (Annular Dark-Field) image of the sample; detecting, by the second electronography detector, the electron beam passing through the first electronography detector, to detect an MABF (Middle-Angle Bright-Field) image, adjusting the focal point of the electron beam to be located on the film of the sample, to obtain a first electronography by the second electronography detector and a second electronography by the first electronography detector; adjusting the focal point of the electron beam to be located on the substrate of the sample, to obtain a third electronography by the second electronography detector and a fourth electronography by the first electronography detector; aligning positions of the second electronography and the fourth electronography, based on the first electronography and the third electronography; and after the aligning, performing an image computation to subtract the fourth electronography from the second electronography, to obtain an image of the film.

DESCRIPTION OF EMBODIMENTS

A description will now be given of the analysis method using the electron microscope, and the electron microscope, in each embodiment according to the present invention. In the drawings, those parts that are the same are designated by the same reference numerals, and a description of the same parts will not be repeated.

First, a description will be given of the STEM in one embodiment, by referring toFIG. 1. In one embodiment, the STEM is a CSTEM (Confocal STEM) that includes a field emission electron gun11and a accelerator12. The field emission electron gun11is an example of an electron source that emits an electron beam10. The accelerator12accelerates the electron beam10emitted from the field emission electron gun11.

The electron beam10that is accelerated by the accelerator12is converged by convergent lenses13and14, and an irradiation half-angle of the electron beam10that is irradiated on a sample40is thereafter adjusted by a convergent lens limiter15.FIG. 1illustrates an example in which a focusing lens has a 2-stage configuration including the convergent lenses13and14. An electron beam probe including the converted electron beam10is deflected by scan coils16that form an example of an electron beam scanner. The electron beam probe further passes through a spherical aberration corrector17, and is thereafter formed into a micro-electron beam probe by an objective lens18and is irradiated on the sample40. In this STEM, the electron beam10can be caused to scan by deflecting the electron beam10by the scan coils16. Atomic images or the like forming the sample40may be obtained by scanning by the sample40by the electron beam10. The spherical aberration corrector17is an example of the spherical aberration correcting apparatus described above, and can correct spherical aberration and chromatic aberration of the electron beam10. The spherical aberration corrector17can reduce a spherical aberration coefficient to 1 μm or less. Although the focusing lens of the STEM illustrated inFIG. 1has the 2-stage configuration including the convergent lenses13and14, the focusing lens may have a multi-stage configuration that includes3or more stages.

By adjusting the convergent lenses13and14, the electron beam10that is adjusted of its focal position and formed into the micro-electron beam probe, is irradiated on the sample40. The micro-electron beam probe is transmitted through the sample40or is scattered at the sample40. The electron beam that is transmitted through or is scattered at the sample40, passes through a projection lens19, and is detected by a first electronography detector21and a second electronography detector22that are arranged at stages subsequent to the sample40. The first electronography detector21detects an ADF-STEM image, and has a ring shape with an aperture21aat a center part thereof. The second electronography detector22detects an MABF (Middle-Angle Bright-Field)-STEM image. The second electronography detector22is configured to detect the electron beam passing through the aperture21aof the first electronography detector21.FIG. 2is a diagram illustrating the electron beam10irradiated on the sample40, and a relationship between the first electronography detector21and the second electronography detector22.

The STEM in one embodiment includes a controller and analyzer50. The controller and analyzer50includes a computing device51that computes an amount of error between image positions, an image position aligning device52, an image normalization device53, an image computing device54, and an image output device55. Image information that is output from the image output device55is displayed on a display device60that is connected to the controller and analyzer50. The controller and analyzer50has functions to control the convergent lenses13and14, the spherical aberration corrector17, the objective lens18, the projection lens19, or the like. The controller and analyzer50may control the scan coils16. In addition, the control and analyzer50has functions to perform an analysis or the like based on information detected by the first electronography detector21and the second electronography detector22.

The controller and analyzer50may be formed by a processor that performs processes of the computing device51, the image position aligning device52, the image normalization device53, the image computing device54, and the image output device55.

(Analysis Method of Electron Microscope)

Next, a description will be given of the analysis method of the electron microscope in one embodiment. When performing the analysis method using the electron microscope in one embodiment, the sample40is a target of the analysis. The sample40includes a substrate41that is made of a crystal formed by an oxide or the like, and a film42that is formed on a surface of the substrate41by crystal growth of a material different from the material forming the substrate41, as illustrated inFIG. 3. In one embodiment, the substrate41is formed by a material including an element lighter than fluorine. For example, the material forming the substrate41may be an oxide, a nitride, a fluoride, carbide, or the like.

In the STEM in one embodiment illustrated inFIG. 1, it is possible to simultaneously obtain the ADF-STEM image by the first electronography detector21and the MABF-STEM image by the second electronography detector22. In general, the ADF-STEM is an observation method by which a high intensity appears at a position where a heavy element exists, and the MABF-STEM is an observation method by which a high intensity appears at a position where a light element exists.

The analysis method using the electron microscope in one embodiment acquires information of atomic positions by irradiating the electron beam perpendicularly with respect to a substrate surface of the sample40. Hence, the substrate41and the film42exist along an incident direction of the electron beam. For this reason, in a case in which the focal position of the electron beam is located on the film42, information of the heavy element included in the material forming the film42and information of the heavy element included in the material forming the substrate41may simultaneously appear in the ADF-STEM image. In other words, in the case in which the focal position of the electron beam is located on the film42, not only the information of the heavy element included in the material forming the film42, but also the information of the heavy element included in the material forming the substrate41may simultaneously appear in the ADF-STEM image. In this case, it is impossible to obtain only the information of the film42. Such a phenomenon becomes more conspicuous as the thickness of the film42becomes thinner.

In addition, in the MABF-STEM image, information of the light element having a higher percentage in the entire sample40appear more conspicuously. Accordingly, in a case in which the substrate41is thick compared to the film42, the information of the light element included in the material forming the substrate41appears as main information in the MABF-STEM image, even when the focal position of the electron beam is located on the film42.

In a case in which the focal position of the electron beam is located on the substrate41, the information of the heavy element included in the material forming the substrate41appears in the ADF-STEM image. In addition, in the case in which the focal position of the electron beam is located on the film42, the information of the light element included in the material forming the substrate41appears as the main information in the MABF-STEM image.

As described above, when the focal position of the electron beam is moved from the substrate41to the film42, a drift generally occurs, and the observation position deviates at the atomic level. In one embodiment, the ADF-STEM image and the MABF-STEM image are simultaneously obtained at the same focal position of the electron beam, and there is no positional error of the images between the ADF-STEM image and the MABF-STEM image. Further, in the case of the MABF-STEM image, even when the focal position of the electron beam is changed from the substrate41to the film42, there is no change in the observed information of the light element. Accordingly, in one embodiment, the positional error of the images is corrected based on the MABF-STEM image for the case in which the focal position of the electron beam is located on the substrate41and the MABF-STEM image for the case in which the focal position of the electron beam is located on the film42. As a result, it is possible to accurately align (or match positions of) the ADF-STEM image for the case in which the focal position of the electron beam is located on the substrate41and the ADF-STEM image for the case in which the focal position of the electron beam is located on the film42.

As described above, the information of the heavy element included in the material forming the film42and the information of the heavy element included in the material forming the substrate41may simultaneously appear in the ADF-STEM image for the case in which the focal position of the electron beam is located on the film42. Only the information of the heavy element included in the material forming the substrate41appears in the ADF-STEM image for the case in which the focal position of the electron beam is located on the substrate41. Accordingly, in one embodiment, the alignment (or position matching) of the ADF-STEM image for the case in which the focal position of the electron beam is located on the film42and the ADF-STEM image for the case in which the focal position of the electron beam is located on the substrate41is performed, based on the MABF-STEM image for the case in which the focal position of the electron beam is located on the film42and the MABF-STEM image for the case in which the focal position of the electron beam is located on the substrate41. Thereafter, an image computation is performed by subtracting the ADF-STEM image for the case in which the focal position of the electron beam is located on the substrate41from the ADF-STEM image for the case in which the focal position of the electron beam is located on the film42. As a result, it is possible to obtain, as an image, the information of the position of the heavy element included in the material forming the film42.

In other words, in one embodiment, the analysis method first obtains the MABF-STEM image and the ADF-STEM image for the case in which the focal position of the electron beam is located on the film42, and the MABF-STEM image and the ADF-STEM image for the case in which the focal position of the electron beam is located on the substrate41. Thereafter, the analysis method performs the image computation between the ADF-STEM image for the case in which the focal position of the electron beam is located on the film42from the ADF-STEM image for the case in which the focal position of the electron beam is located on the substrate41, to obtain the image information of the film42.

In the case of a high-resolution STEM image, the electron beam that is converged to nm order or less is irradiated on the sample40and diffracted at the sample40. Electrons reaching a ring-shaped ADF detector that is provided at a diffraction image surface are counted. The counted number of electrons is synchronized to the position of the incident electrons, and used as an intensity of the image. Such an operation is performed while causing the converged electron beam to scan, to thereby obtain a 2-dimensional dark-field STEM image. This 2-dimensional dark-field STEM image is generally referred to as an HAADF (High-Angle Annular Dark-Field)-STEM image, which is a type of ADF-STEM image. According to the HAADF-STEM image, an intensity corresponding to an atomic number of an element of an atom is obtained at the position of the atom. In addition, because a contrast of the image is considerably insensitive to a focal point of the electromagnetic lens that converges the electron beam, and to the thickness of the sample, it is possible to obtain an image having a superior direct viewing of the atom. In the CSTEM, a spatial resolution of the image depends on a diameter of the converged electron beam, and in the case in which the spherical aberration correcting apparatus is used, the spatial resolution can be reduced to 1 μm or less. Because of these features, the CSTEM is popularly used also for the structural analysis.

In one embodiment, the ring-shaped first electronography detector21is used when detecting the HAADF-STEM image. Accordingly, the electron beam passing through the aperture21aformed at the center part of the first electronography detector21is detected by the disk-shaped second electronography detector22. The image that is obtained from the electron beam detected by the disk-shaped second electronography detector22is generally referred to as a BF (Bright-Field)-STEM image. Characteristics of the BF-STEM image greatly changes according to beam acquiring conditions that are set for the disk-shaped second electronography detector22. The image that is obtained by setting a beam acquiring angle to a large angle is generally known as a complementary image of the HAADF-STEM image, and is categorized as a HABF (High-Angle Bright-Field)-STEM image. In addition, a BF-STEM image that is obtained by setting the beam acquiring angle to a medium angle on the order of 9 mrad (milli-radians) to 12 mrad is categorized as an MABF-STEM image, and it is known that the image is bright at the position of the light element.

Next, a description will be given of a simulation of the analysis method using the electron microscope in one embodiment. This simulation employs a model of the sample40having a configuration that includes an SrTiO3crystal substrate as the substrate41, and an LaCoO3crystal film that is formed as the film42on the substrate41by crystal growth. In addition, in the model of the sample40, the substrate41has a thickness of 68 nm, and the film42has a thickness of 12 nm, and the atomic positions in the substrate41and the film42are shifted by (1/4 1/4 0) with reference to a unit cell. The incident direction of the electron beam is set to a [001] direction, and the method of acquiring the 3-dimensional tomogram is similar to the method proposed in Japanese Laid-Open Patent Publication No. 2012-43563. Because the electron beam formed by the electromagnetic lens and subjected to the spherical aberration correction has a considerably shallow DOF, the method proposed in Japanese Laid-Open Patent Publication No. 2012-43563 obtains the image by varying the focal point of the electromagnetic lens so that the focal point is located at a part that is the observation target.

As illustrated inFIG. 5, in the case in which the focal position of the electron beam is located on the film42, the computation is performed in a defocused state so that the focal point is located at a position having a depth of 5 nm from the surface of the film42in the sample40in a direction (hereinafter also referred to as a “depth direction”) in which the depth is taken (Df=−5 nm inFIG. 5). On the other hand, in the case in which the focal position of the electron beam is located at the substrate41, the computation is performed in the defocused state so that the focal point is located at a position having a depth of 30 nm from the surface of the film42in the sample40in the depth direction (Df=−30 nm inFIG. 5).FIGS. 6A and 6Bare diagrams illustrating electronographies obtained by the simulation for the case in which the focal position of the electron beam is located on the film42. More particularly,FIG. 6Aillustrates an MABF-STEM image for the case in which the focal position of the electron beam is located at the position having the depth of 5 nm in the depth direction from the surface of the film42in the sample40. On the other hand,FIG. 6Billustrates an ADF-STEM image for the case in which the focal position of the electron beam is located at the position having the depth of 5 nm in the depth direction from the surface of the film42in the sample40.FIGS. 6C and 6Dare diagrams illustrating electronographies obtained by the simulation for the case in which the focal position of the electron beam is located on the substrate41. More particularly,FIG. 6Cillustrates an MABF-STEM image for the case in which the focal position of the electron beam is located at the position having the depth of 30 nm in the depth direction from the surface of the film42in the sample40. On the other hand,FIG. 6Dillustrates an ADF-STEM image for the case in which the focal position of the electron beam is located at the position having the depth of 30 nm in the depth direction from the surface of the film42in the sample40.

In one embodiment, the MABF-STEM image illustrated inFIG. 6Amay be referred to as a first electronography, and the ADF-STEM image illustrated inFIG. 6Bmay be referred to as a second electronography. In addition, the MABF-STEM image illustrated inFIG. 6Cmay be referred to as a third electronography, and the ADF-STEM image illustrated inFIG. 6Dmay be referred to as a fourth electronography.

Next, a more detailed description will be given of the STEM images that are obtained.FIG. 7Aillustrates a state for the case in which the focal position of the electron beam is located on the film42, that is, the focal position of the electron beam is located at the position having the depth of 5 nm in the depth direction from the surface of the sample40(Df=−5 nm inFIG. 7A).FIG. 7Billustrates an MABF-STEM image (first electronography) that is obtained in this case, andFIG. 7Cillustrates an ADF-STEM image (second electronography) that is obtained in this case. In the MABF-STEM image (first electronography) illustrated inFIG. 7B, the position of the light element in the substrate41, that is, the position of the oxygen (O) in the SrTiO3forming the substrate41, appears brightest. In addition, in the ADF-STEM image (second electronography) illustrated inFIG. 7C, the position of the heavy element in the substrate41and the position of the heavy element in the film42appear bright. In other words, the positions of Sr and Ti in the SrTiO3forming the substrate41, and the positions of La and Co in the LaCoO3forming the film42, appear bright in the ADF-STEM image (second electronography) illustrated inFIG. 7C. This is because thermal diffuse scattering electrons scattered from the heavy elements existing at the focal position of the electron beam are detected in the ADF-STEM image (second electronography) illustrated inFIG. 7C, and the heavy elements at the focal position mainly appear in the image. On the other hand, in the MABF-STEM image (first electronography) illustrated inFIG. 7B, the position of the light element in the substrate41appear brightest, because in the entire sample40, the position where the amount of light element is the largest appears brightest in the image.

FIG. 8Aillustrates a state for the case in which the focal position of the electron beam is located on the substrate41, that is, the focal position of the electron beam is located at the position having the depth of 30 nm in the depth direction from the surface of the sample40Df=−30 nm inFIG. 8A).FIG. 8Billustrates an MABF-STEM image (third electronography) that is obtained in this case, andFIG. 8Cillustrates an ADF-STEM image (fourth electronography) that is obtained in this case. In the MABF-STEM image (third electronography) illustrated inFIG. 8B, the position of the light element in the substrate41, that is, the position of the oxygen (O) in the SrTiO3forming the substrate41, appears brightest. In addition, in the ADF-STEM image (fourth electronography) illustrated inFIG. 8C, the position of the heavy element in the substrate41, that is, the positions of Sr and Ti in the SrTiO3forming the substrate41, appear bright.

In one embodiment, the amount of error between the image positions is first computed from the MABF-STEM image (first electronography) for the case in which the focal position of the electron beam is located on the film42and the MABF-STEM image (third electronography) for the case in which the focal position of the electron beam is located on the substrate41. Thereafter, the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42and the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41are relatively shifted by the computed amount of error between the image positions. Hence, it is possible to match the positions of the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42and the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41. Thereafter, the brightness of the image is normalized in the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42and the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41. Thereafter, an image computation is performed to subtract the ADF-STEM image (fourth electronography) illustrated inFIG. 9Bfor the case in which the focal position of the electron beam is located on the substrate41from the ADF-STEM image (second electronography) illustrated inFIG. 9Afor the case in which the focal position of the electron beam is located on the film42. As a result of this image computation, an image illustrated inFIG. 9Cis obtained. The image illustrated inFIG. 9Cindicates the structure of the film42, that is, the positions of the heavy elements La and Co in LaCoO3forming the film42.

The method of computing the amount of error between the image positions from the MABF-STEM image for the case in which the focal position of the electron beam is located on the film42and the MABF-STEM image for the case in which the focal position of the electron beam is located on the substrate41, may include the correlation method, the phase-only correlation method, or the like.

Next, a description will be given of the analysis method using the electron microscope in one embodiment, by referring to the flow chart illustrated inFIG. 10.

First, in step S102, the MABF-STEM image (first electronography) for the case in which the focal position of the electron beam is located on the film42and the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42are acquired. More particularly, the electron beam is irradiated by adjusting the focal position of the electron beam to be located on the film42of the sample40, and the electron beam that is transmitted through the sample40, or scattered in the sample40, is detected by the first electronography detector21and the second electronography detector22. Hence, the MABF-STEM image (first electronography) for the case in which the focal position of the electron beam is located on the film42is detected by the second electronography detector22. In addition, the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42is detected by the first electronography detector21.

Next, in step S104, the MABF-STEM image (third electronography) for the case in which the focal position of the electron beam is located on the substrate41and the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41are acquired. More particularly, the electron beam is irradiated by adjusting the focal position of the electron beam to be located on the substrate41of the sample40, and the electron beam that is transmitted through the sample40, or scattered in the sample40, is detected by the first electronography detector21and the second electronography detector22. Hence, the MABF-STEM image (third electronography) for the case in which the focal position of the electron beam is located on the substrate41is detected by the second electronography detector22. In addition, the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41is detected by the first electronography detector21.

Next, in step S106, the amount of error between the image positions for the case in which the focal position of the electron beam is located on the film42and the case in which the focal position of the electron beam is located on the substrate41is computed. More particularly, the MABF-STEM image (first electronography) for the case in which the focal position of the electron beam is located on the film42and the MABF-STEM image (third electronography) for the case in which the focal position of the electron beam is located on the substrate41are input to the computing device51of the controller and analyzer50. Thereafter, the computing device51computes the amount of error between the image positions, based on the MABF-STEM image (first electronography) for the case in which the focal position of the electron beam is located on the film42and the MABF-STEM image (third electronography) for the case in which the focal position of the electron beam is located on the substrate41.

Next, in step S108, the alignment (or position matching) of the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42and the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41is performed. In other words, based on the amount of error between the image positions computed in step S106, the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41is moved with respect to the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42. The process of step S108is performed by the image position aligning device52. Accordingly, it is possible to align (or match positions of) the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42and the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41. The position of the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42and the position of the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41can be aligned (or matched) in this manner.

Next, in step S110, the brightness intensity of the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42and the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41is normalized. The image normalization device53performs this normalization process. More particularly, the normalization process causes the brightness of the heavy element in the substrate41to approximately match between the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42and the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41.

Next, in step5112, the image computation is performed to subtract the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41from the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42. As a result, in the image of the film42is obtained. More particularly, the image computing device54performs the image computation to subtract the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41from the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42. The image of the film42that is obtained by this image computation is displayed on the display device60via through image output device44. Accordingly, in the case in which the film42is formed from LaCoO3, it is possible to know the structure of LaCoO3forming the film42, that is, the positions of La and Co in LaCoO3.

Next, a description will be given of one exemplary implementation according to one embodiment. In one exemplary implementation, the sample40uses, as the substrate41, an SrTiO3(001) substrate, and LaCoO3including distortion is grown on the substrate41, as the film42.

FIG. 11illustrates the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42of the sample40, andFIG. 12is a diagram illustrating the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41of the sample40. In one exemplary implementation, the amount of error between the image positions is first computed, based on the MABF-STEM image (first electronography) for the case in which the focal position of the electron beam is located on the film42and the MABF-STEM image (third electronography) for the case in which the focal position of the electron beam is located on the substrate41. Next, the alignment (or position matching) of the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42and the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41is performed. Then, the normalization is performed to level the brightness of the images with respect to the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42and the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41. Next, the image computation is performed to subtract the ADF-STEM image (fourth electronography) for the case in which the focal position of the electron beam is located on the substrate41from the ADF-STEM image (second electronography) for the case in which the focal position of the electron beam is located on the film42. As a result, as illustrated inFIG. 13, it is possible to obtain the image of the film42, which is made of LaCoO3and is grown on the substrate41.FIG. 14illustrates an image that is obtained by performing an FFT (Fast Fourier Transform) on the obtained image illustrated inFIG. 13.

According to one exemplary implementation, it is possible to obtain the image of an atomic arrangement in the film42that is deposited on the substrate41. For this reason, it is possible to easily know the distortion or the like in the film42that is deposited on the substrate41.

According to the disclosed analysis method using electron microscope, and the disclosed electron microscope, it is possible to definitely detect the atomic deviation and distortion of the film that is deposited on the substrate.