Charged particle beam device and sample observation method

Abstract

A charged particle beam device 100 includes an electron beam irradiation unit 1, a sample holder 9, and a light irradiation unit 12. The sample holder 5 has a first electrode part 15, a first potential transmission part 16 connected to the first electrode part 15, and a second potential transmission part. A predetermined potential difference is generated in a sample 5 by irradiating the first electrode part 15 with pulsed light 13 from the light irradiation part 12. Time-resolved observation data of the sample 5 can be acquired by irradiating the sample 5 with a pulsed electron beam 2 from the electron beam irradiation unit 1 while synchronizing the irradiation cycle of the pulsed light 13 with the irradiation cycle of the pulsed electron beam 2.

Description

Charged particle beam device and sample observation method

[0001] The present invention relates to a charged particle beam device and a sample observation method.

[0002] Charged particle beam devices are used in a variety of fields, from physical science research to biology, to observe and analyze the structure of materials at atomic resolution. In particular, for atomic-level observations, electrons are accelerated by an accelerating voltage of 100 kV or higher, and a short-wavelength electron beam is used. Examples of such charged particle beam devices include transmission electron microscopes (TEMs) and scanning transmission electron microscopes (STEMs). In a transmission electron microscope, an electron beam transmitted through a sample is focused by a lens to obtain an image of the sample. In a transmission electron microscope, a finely focused electron beam is irradiated onto the sample, and the transmitted electrons are detected while the electron beam is scanned, thereby obtaining an image of the sample.

[0003] In recent years, with the practical application of aberration correctors, electron microscopes equipped with aberration correctors can achieve atomic resolution even at an accelerating voltage of around 30 kV. Furthermore, the accelerating voltage of an electron microscope can be selected according to the purpose of observation.

[0004] On the other hand, in research into physical properties, semiconductors, or environmental batteries, time-resolved observations are also required to analyze how the subject behaves when voltage is applied.

[0005] For example, as disclosed in Patent Document 1, a method is used in which a sample itself is irradiated with pulsed light to cause an interaction between the sample and the light, and a pulsed electron wave is irradiated onto the sample, thereby observing the sample with time resolution. The pulsed light is also called "pump light" in the sense that it stimulates the sample, and the pulsed electron wave is also called "probe electron" in the sense that it measures the sample, and the method of Patent Document 1 is called the pump-probe method.

[0006] In the pump-probe method, the timing of irradiating the sample with probe electrons is gradually changed relative to the timing of irradiating the sample with pump light, allowing for time-resolved observation of the sample. This allows for measurement of the temporal changes in the sample before and after stimulating the sample with pump light with high time resolution of sub-nanoseconds, without being limited by the camera's capture speed.

[0007] U.S. Pat. No. 1,155,1906

[0008] In conventional pump-probe methods, the sample itself is irradiated with light to stimulate it, which causes interactions such as heating, light absorption, or electronic excitation, and therefore it is not possible to supply a purely controlled potential difference to the sample.

[0009] Therefore, in the conventional pump-probe method, as shown in Figure 1, a lead wire 10 is introduced into a sample holder 9, and the potential difference supplied from an external power source 11 to a sample 5 is controlled. In this state, a pulsed electron wave 2 is irradiated from an electron beam irradiation unit 1 onto the sample 5, and the sample is observed with time resolution.

[0010] However, because the specimen holder 9 must be inserted from the outside of the electron microscope into the center of the microscope, the specimen holder 9 typically has a long, narrow shape of 200 mm or more. The internal conductor 10 of the specimen holder 9 and the specimen holder 9 form a structure similar to that of a coaxial cable, and the finite cutoff frequency becomes a physical barrier. Therefore, it is difficult to change the potential of the specimen 5 over time from the external power source 11 at a speed faster than approximately 1 MHz (potential control speed of approximately 1 microsecond). In other words, it is difficult to rapidly generate a predetermined potential difference in the specimen using this cutoff frequency and perform time-resolved observations with the electron microscope.

[0011] The main object of the present application is to provide a technique for generating a predetermined potential difference across a sample at high speed, thereby enabling high-speed observation of the sample with time resolution. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings.

[0012] A brief summary of a representative embodiment of the present invention will be given below.

[0013] In one embodiment, a charged particle beam device includes a charged particle beam irradiation unit for irradiating a sample with a pulsed charged particle wave, a sample holder for placing the sample, and a light irradiation unit for irradiating the electrode unit with pulsed light. The sample holder has an electrode unit, a first potential transmission unit connected to the electrode unit, and a second potential transmission unit. When the sample is placed on the sample holder, the sample is electrically connected to the first potential transmission unit and the second potential transmission unit. When the light irradiation unit irradiates the electrode unit with the pulsed light, a predetermined potential difference is generated in the sample. The charged particle beam irradiation unit irradiates the sample with the pulsed charged particle wave while synchronizing the period of irradiation of the pulsed light and the period of irradiation of the pulsed charged particle wave.

[0014] In one embodiment, a charged particle beam device includes a charged particle beam irradiation unit for irradiating a sample with a pulsed charged particle wave, a sample holder for placing the sample on it, and a light irradiation unit for irradiating the electrode unit with pulsed light. The sample holder has an electrode unit, a first potential transmission unit and a second potential transmission unit connected to the electrode unit. When the sample is placed on the sample holder, the sample is not in direct contact with the first potential transmission unit and the second potential transmission unit. The light irradiation unit irradiates the electrode unit with the pulsed light, generating a predetermined stress in the sample. The charged particle beam irradiation unit irradiates the sample with the pulsed charged particle wave while synchronizing the period of irradiation of the pulsed light with the period of irradiation of the pulsed charged particle wave.

[0015] In one embodiment, a sample observation method is a method for acquiring time-resolved observation data of a sample using a charged particle beam irradiation unit for irradiating a pulsed charged particle wave, a sample holder having an electrode unit, a first potential transmission unit and a second potential transmission unit connected to the electrode unit, and a light irradiation unit for irradiating a pulsed light, wherein when the sample is placed on the sample holder, the sample is electrically connected to the first potential transmission unit and the second potential transmission unit, and the light irradiation unit irradiates the electrode unit with the pulsed light, generating a predetermined potential difference in the sample, and the charged particle beam irradiation unit irradiates the sample with the pulsed charged particle wave while synchronizing the period of irradiation of the pulsed light and the period of irradiation of the pulsed charged particle wave, thereby acquiring time-resolved observation data of the sample using a charged particle beam device.

[0016] According to one embodiment, it is possible to provide a technique for generating a predetermined potential difference in a sample at high speed and for performing high-speed observation of the sample with time resolution.

[0017] 1 is a schematic diagram showing a charged particle beam device in the prior art; FIG. 1 is a schematic diagram showing a charged particle beam device in embodiment 1; FIG. 2 is a schematic diagram showing a sample holder in embodiment 1; FIG. 3 is a schematic diagram showing a potential difference measuring unit and deflection of a pulsed electron wave in embodiment 1; FIG. 4 is a schematic diagram showing a GUI in embodiment 1; FIG. 5 is a graph showing relationship information between the intensity of pulsed light and the potential difference in embodiment 1; FIG. 6 is a graph showing temporal changes in the potential difference and the intensity of the pulsed electron wave in embodiment 1; FIG. 7 is a graph showing temporal changes in the potential difference and the intensity of the pulsed electron wave in embodiment 1; FIG. 8 is a flowchart showing a sample observation method in embodiment 1; FIG. 9 is a schematic diagram showing a sample holder in embodiment 2; FIG. 10 is a schematic diagram showing a charged particle beam device in embodiment 3; FIG. 11 is a schematic diagram showing a charged particle beam device in embodiment 4; FIG. 12 is a schematic diagram showing a charged particle beam device in modification 1 of embodiment 4; FIG. 13 is a schematic diagram showing a charged particle beam device in modification 2 of embodiment 4; FIG. 14 is a schematic diagram showing a charged particle beam device in modification 3 of embodiment 4;

[0018] Hereinafter, embodiments will be described in detail with reference to the drawings. In all drawings for explaining the embodiments, components having the same functions are designated by the same reference numerals, and repeated explanations thereof will be omitted. In the following embodiments, explanations of the same or similar parts will not be repeated unless particularly necessary.

[0019] In the embodiments, a charged particle beam device using an electron beam (pulsed electron wave) as a charged particle beam will be described. However, the charged particle beam device can also be applied to cases where the charged particle beam is an ion beam or a neutron beam.

[0020] 2 to 9, a charged particle beam device 100 according to the first embodiment will be described. The charged particle beam device 100 is, for example, a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM).

[0021] As shown in FIG. 2 , the charged particle beam device 100 includes a housing 54, an electron beam irradiation unit 1, a first irradiation electron lens 3, a second irradiation electron lens 4, an objective lens 6, a magnifying lens 7, a sample holder 9, a light irradiation unit 12, a mirror 14, a control personal computer (control PC) 50, a monitor 51, and a control system 52.

[0022] The electron beam irradiation unit 1, the first irradiation electron lens 3, the second irradiation electron lens 4, the objective lens 6, the magnifying lens 7, the sample holder 9, and the mirror 14 are provided inside a housing 54. When observing the sample 5, the inside of the housing 54 is evacuated to a vacuum by a vacuum pump (not shown).

[0023] The electron beam irradiation unit (charged particle beam irradiation unit) 1 is attached to the housing 54 and is provided to irradiate a pulsed electron wave (pulsed charged particle wave) 2. The electron beam irradiation unit 1 has a pulsed electron source.

[0024] The pulsed electron source irradiates the electron source with a pulsed laser, accelerates the laser-excited electrons, and introduces the pulsed electron wave 2 into the housing 54. Alternatively, the pulsed electron source irradiates the back surface of the electron source with a pulsed laser, accelerates the electrons emitted from the front surface of the electron source, and introduces the pulsed electron wave 2 into the housing 54. Alternatively, the pulsed electron source uses a beam chopper such as electrostatic blanking to introduce the accelerated electron beam emitted from the electron source into the housing 54 as the pulsed electron wave 2. Although not shown, the electron beam irradiating unit 1 has a laser light source for irradiating the electron source with a pulsed laser, a mirror, a lens, an electrostatic blanking mechanism for chopping the electron beam, and the like.

[0025] The sample holder 9 is provided for placing the sample 5 thereon. The sample holder 9 also has a first electrode unit 15. The pulsed electron wave 2 emitted from the electron beam irradiation unit 1 is irradiated onto the sample 5 after the irradiation conditions are adjusted by the first irradiation electron lens 3 and the second irradiation electron lens 4. Two or more irradiation electron lenses may be used. Although not shown, an aperture may be provided between the electron beam irradiation unit 1 and the sample 5 in order to adjust the electron wave irradiation area on the sample 5.

[0026] The pulsed electron wave 2 transmitted through the sample 5 is enlarged or reduced by the action of the objective lens 6 and the magnifying lens 7, and is detected as an electron microscope image using a camera or the like installed near the observation surface 8.

[0027] The light irradiation unit 12 is provided to irradiate pulsed light 13 and has a pulsed light source. The pulsed light 13 emitted from the pulsed light source is reflected and collected by a mirror 14, and is irradiated onto a first electrode unit 15. The first electrode unit 15 is electrically connected to the sample 5. Although not shown, the light irradiation unit 12 also has a mechanism for adjusting the wavelength of the pulsed light 13 emitted from the pulsed light source, the pulse width and pulse interval of the pulsed light 13 in the time direction, and the timing of irradiating the pulsed light 13. As will be described later, the pulsed light 13 may also be irradiated onto a second electrode unit 18.

[0028] Furthermore, the light irradiation unit 12 is provided outside the housing 54. The housing 54 is provided with a window for introducing the pulsed light 13 from the light irradiation unit 12 into the inside of the housing 54. Furthermore, for the purpose of adjusting the focus of the pulsed light 13, multiple lenses or multiple mirrors may be provided between the light irradiation unit 12 and the mirror 14.

[0029] The control system 52 controls the operations of the electron beam irradiation unit 1, the first irradiation electron lens 3, the second irradiation electron lens 4, the objective lens 6, the magnifying lens 7, the sample holder 9, and the light irradiation unit 12. Although not shown, the control system 52 also controls mechanisms such as a deflection system that changes the traveling direction of the pulsed electron wave 2 and an aperture that limits the area through which the pulsed electron wave 2 passes. The control system 52 also controls measurements by the electron detector 53.

[0030] The control PC 50 is electrically connected to the control system 52, manages various information processes performed in the charged particle beam device 100, and issues instructions to the control system 52. The control PC 50 has a typical computer configuration, such as a central processing unit (CPU), a memory serving as a storage unit, an input / output interface, etc. In this specification, the control PC 50 and the control system 52 may be collectively referred to as the "control unit" of the charged particle beam device 100.

[0031] The monitor 51 is electrically connected to the charged particle beam device 100. Various pieces of information performed by the charged particle beam device 100 are displayed on the monitor 51 as a GUI (Graphical User Interface). When a user works on the monitor 51 using an input / output interface provided in the control PC, various pieces of information are input to or output from the control PC.

[0032] 3 shows a detailed structure of the sample holder 9. As shown in FIG. 3, the sample holder 9 has a MEMS (Micro Electro Mechanical System) chip 23, a first electrode unit 15, a first potential transmission unit 16, a second electrode unit 18, and a second potential transmission unit 19. Here, the first electrode unit 15, the first potential transmission unit 16, the second electrode unit 18, and the second potential transmission unit 19 are provided on the MEMS chip 23. The sample 5 is placed on the MEMS chip 23.

[0033] The first electrode 15 is a portion irradiated with the pulsed light 13 and is connected to a first potential transmitter 16. The second electrode 18 is a portion irradiated with the pulsed light 13 and is connected to a second potential transmitter 19.

[0034] When the sample 5 is placed on the sample holder 9 (MEMS chip 23), the sample 5 is electrically connected to the first potential transmission unit 16 and the second potential transmission unit 19 so as to bridge between the first potential transmission unit 16 and the second potential transmission unit 19. The first electrode unit 15, the first potential transmission unit 16, the second electrode unit 18, and the second potential transmission unit 19 are made of conductors with low electrical resistance.

[0035] The sample 5 is thinned using, for example, a focused ion beam (FIB) device so that the pulsed electron wave 2 incident from a direction perpendicular to the plane of the paper in Fig. 3 can pass through the sample 5. The sample holder 9 and the MEMS chip 23 are provided with holes 24 so that the pulsed electron wave 2 can pass through. The holes 24 may be membranes.

[0036] The shape of the MEMS chip 23 is not limited to that shown in FIG. 3, and it is sufficient if the MEMS chip 23 has the first electrode portion 15, the first potential transmission portion 16, the second electrode portion 18, and the second potential transmission portion 19.

[0037] Furthermore, either the first electrode unit 15 or the second electrode unit 18 may not be provided. For example, the second electrode unit 18 may not be provided, and the second potential transmission unit 19 may be electrically connected to a ground or an external power supply (not shown) via a conductor having an appropriate resistance. In this case, the shape, resistance, capacitance, and dielectric constant of the conductor relate to the response frequency when viewed as a circuit including the sample 5, and the shape, resistance, capacitance, and dielectric constant of the conductor can be selected according to the target response frequency. Furthermore, a resistor and a capacitor may be mounted on the MEMS chip 23.

[0038] When the light irradiation unit 12 irradiates the first electrode unit 15 with pulsed light 13, electrons are emitted from the first electrode unit 15 due to the photoelectric effect, and a predetermined potential difference is generated in the sample 5. In order to emit electrons from the first electrode unit 15, the surface of the first electrode unit 15 is irradiated with pulsed light 13 having energy greater than the work function.

[0039] For example, if the material constituting the first electrode unit 15 is platinum and the work function of platinum is 5.3 eV, the wavelength of the pulsed light 13 is shorter than 234 nm. By adjusting the intensity of the pulsed light 13 irradiated onto the first electrode unit 15, the potential difference between the first electrode unit 15 and the second electrode unit 18 can be adjusted, and a potential difference can be applied to the left and right sides of the sample 5 by the first potential transmission unit 16 and the second potential transmission unit 19. The intensity of the pulsed light 13 is the number of photons irradiated onto the first electrode unit 15 per unit time.

[0040] Furthermore, by changing the position at which the pulsed light 13 is irradiated to the second electrode portion 18, a potential difference of the opposite polarity can be applied to the sample 5 compared to when the pulsed light 13 is irradiated to the first electrode portion 15.

[0041] In Figure 3, the first potential transmission unit 16 and the second potential transmission unit 19 are placed on the left and right sides of the sample 5 as positions for applying a potential difference to the sample 5, but if it is desired to apply a potential difference to a specific location on the sample 5, the positions of the first potential transmission unit 16 and the second potential transmission unit 19 can be changed.

[0042] The emission of electrons from the first electrode 15 due to the photoelectric effect occurs in an extremely short time, such as attoseconds to femtoseconds, allowing the potential of the sample 5 to be controlled at a speed significantly faster than conventional methods (for example, nanoseconds).

[0043] The sample holder 9 (MEMS chip 23) further includes a potential difference measuring unit 22 for measuring the potential difference occurring in the sample 5. That is, the potential difference measuring unit 22 has a third electrode unit 20 electrically connected to the first potential transmitting unit 16 and a fourth electrode unit 21 electrically connected to the second potential transmitting unit 19 in order to measure the potential difference between the first potential transmitting unit 16 and the second potential transmitting unit 19.

[0044] 4 is a schematic diagram of the potential difference measuring unit 22 as viewed from a direction perpendicular to the path of the pulsed electron wave 2. An electric field is generated by the potential difference generated between the third electrode unit 20 and the fourth electrode unit 21. The propagation direction of the pulsed electron wave 2 is deflected by the influence of this electric field.

[0045] An analysis is performed by electron beam path simulation based on the relationship between the deflection amount of the pulsed electron wave 2, the distance W between the third electrode unit 20 and the fourth electrode unit 21, and the height H of each of the third electrode unit 20 and the fourth electrode unit 21. This analysis makes it possible to calculate the potential difference between the third electrode unit 20 and the fourth electrode unit 21, that is, the potential difference between the first potential transmission unit 16 and the second potential transmission unit 19, and the potential difference generated in the sample 5.

[0046] A method for measuring the deflection amount of the pulsed electron wave 2 includes, for example, the TIE (Transport Intensity Equation) method, which involves shifting the focus during image observation using an electron microscope and analyzing the distribution of image contrast associated with the deflection of the electron beam. Other methods include a method using Lorentz microscopy, a method using electron holography, or a method using STEM. The method for measuring the deflection amount of the pulsed electron wave 2 by the potential difference measuring unit 22 is not limited to these methods.

[0047] 5 shows an example of a GUI displayed on the monitor 51. Before irradiating the first electrode unit 15 with the pulsed light 13, the irradiation position of the pulsed light 13 and the size of the pulsed light 13 are adjusted.

[0048] On the GUI, a planned sample position 5a where the sample 5 is to be placed is displayed in a light irradiation area 30. Within the light irradiation area 30, the irradiation position and size of the pulsed light 13 are set in order to irradiate the first electrode unit 15 with the pulsed light 13. The user can adjust the X, Y, and Z coordinates of the pulsed light 13 by manipulating the irradiation position and irradiation size 31 displayed as a circle on the GUI using, for example, a mouse. Alternatively, the user may input numerical values ​​into the X, Y, and Z coordinates using, for example, a keyboard.

[0049] The shape of the MEMS chip 23, the position of the intended sample position 5a, and the positions of the first electrode unit 15, the first potential transmission unit 16, the second potential transmission unit 19, and the potential difference measurement unit 22 are predetermined depending on the type of MEMS chip 23. Therefore, by the user selecting "MEMS Pattern," various patterns of the MEMS chip 23 can be read out.

[0050] The relationship between the irradiation intensity of the pulsed light 13 and the potential difference generated in the sample 5 is calibrated before the actual measurement.

[0051] The user inputs the minimum and maximum values ​​of the irradiation intensity of the pulsed light 13 and the number of steps for acquiring the calibration data. The user also inputs the acceleration voltage of the pulsed electron wave 2 and the shape and dimensions of the potential difference measuring unit 22. Thereafter, the user presses the "Execute" button.

[0052] By performing calculations using this information, relationship information between the irradiation intensity of the pulsed light 13 and the potential difference generated in the potential difference measuring unit 22 (potential difference generated in the sample 5) is obtained, as shown in Fig. 6. The GUI also has a function for "saving" and "reading" all of this information so that it can be used repeatedly.

[0053] In actual measurements, in order to generate a predetermined potential difference in the sample 5, the irradiation intensity of the pulsed light 13 is adjusted based on the relationship information in Figure 6, and then the pulsed light 13 is irradiated onto the first electrode unit 15 or the second electrode unit 18.

[0054] 7 and 8 show the time-dependent changes in the potential difference generated in the sample 5 and the intensity of the pulsed electron wave 2. FIG.

[0055] As shown in FIG. 7, first, the first electrode 15 or the second electrode 18 is irradiated with pulsed light 13, and a predetermined potential difference is applied to the sample 5 for a certain period of time.

[0056] Thereafter, the sample 5 is irradiated with a pulsed electron wave 2 at a timing with a time difference δτ with respect to the timing of irradiating the sample 5 with the pulsed light 13, and the sample 5 is observed. Generally, when observing with a time resolution of nanoseconds or less, the number of electrons that can be injected into one pulsed electron wave 2 is finite, and therefore, in many cases, the S / N (Signal / Noise) ratio is insufficient in a single measurement.

[0057] Therefore, by irradiating the sample 5 with the pulsed electron wave 2 from the electron beam irradiation unit 1 while synchronizing the irradiation period T of the pulsed light 13 with the irradiation period T of the pulsed electron wave 2, observation data with a time resolution of the sample 5 can be acquired. That is, observation is repeatedly performed in which the pulsed electron wave 2 is irradiated onto the sample 5 at a timing with a time difference δτ with respect to the timing of irradiating the sample 5 with the pulsed light 13. In this way, observation data with a time resolution of the sample 5 at a certain time difference δτ can be acquired.

[0058] Furthermore, the time difference δτ is changed multiple times to obtain observation data with time resolution of the sample 5. That is, by changing the timing of irradiating the first electrode unit 15 or the second electrode unit 18 with the pulsed electron wave 2 multiple times with respect to the timing of irradiating the sample 5 with the pulsed light 13, observation data with time resolution of the sample 5 can be obtained for each multiple times.

[0059] When the measurement method shown in Figure 7 is used, for example, it is possible to analyze the behavior of carriers in sample 5 as they start to move when a potential difference begins to occur, and then as the potential difference returns to 0 V (zero volts), until the carriers relax to a steady state.

[0060] Fig. 8 is similar to Fig. 7 in terms of acquiring observation data with time resolution of the sample 5, but Fig. 8 has a different waveform of the pulsed light 13 compared to Fig. 7. As shown in Fig. 8, the pulsed light 13 is irradiated from the light irradiating unit 12 to the first electrode unit 15 or the second electrode unit 18 so that the potential difference generated in the sample 5 changes continuously over time during one cycle T of irradiation of the pulsed light 13.

[0061] When the measurement method shown in Figure 8 is used, for example, in a device operating at high frequency, it is possible to locally analyze with nanoscale resolution which part of the device is experiencing a potential difference or conductance defect that is the rate-limiting factor for operating the device at high speed.

[0062] The waveforms of the potential difference shown in FIGS. 7 and 8 are merely examples, and a waveform of the potential difference other than those shown in FIGS. 7 and 8 may be applied to the sample depending on the target of analysis or the content of the analysis to be performed.

[0063] 9 is a flowchart showing a sample observation method according to embodiment 1. First, in step S1, relationship information between the irradiation intensity of pulsed light 13 and the potential difference generated in potential difference measuring unit 22 (potential difference generated in sample 5) is acquired, as shown in FIG.

[0064] Next, in step S2, conditions for potential difference control and image capture are set. For example, a potential difference waveform is set as described with reference to Figures 7 and 8. Also, the maximum potential difference, the amplitude of the potential difference, the period T, the number of measurements, the amount of change in the time difference δτ, and the measurement time per measurement are set.

[0065] Next, in step S3, the sample 5 is observed. That is, when the sample 5 is placed on the sample holder 9, the sample 5 is electrically connected to the first potential transmitter 16 and the second potential transmitter 19. By irradiating the first electrode unit 15 or the second electrode unit 18 with pulsed light 13 from the light irradiator 12, a predetermined potential difference is generated in the sample 5. By irradiating the sample 5 with the pulsed electron wave 2 from the electron beam irradiator 1 while synchronizing the irradiation cycle of the pulsed light 13 with the irradiation cycle of the pulsed electron wave 2, observation data of the sample 5 with time resolution is acquired.

[0066] As described above, according to the charged particle beam device 100 and the sample observation method of the first embodiment, a predetermined potential difference can be generated in the sample 5 at high speed, enabling high-speed observation of the sample 5 with time resolution. For example, the potential difference generated in the sample 5 can be controlled at a frequency on the THz level, enabling time-resolved observation of the sample 5. For example, if the sample 5 is a semiconductor device, it is possible to observe the carrier movement accompanying a change in potential difference, thereby clarifying the distribution and pinning mechanism of carriers trapped at junction interfaces or defects. Note that this method can be applied not only to semiconductor devices but also to various materials for the environmental field.

[0067] (Embodiment 2) A charged particle beam device 100 according to embodiment 2 will be described below with reference to Fig. 10. In the following description, differences from embodiment 1 will be mainly described, and descriptions of points that overlap with embodiment 1 will be omitted.

[0068] Fig. 10 is a schematic diagram showing a sample holder 9 in the second embodiment. In the second embodiment, the sample holder 9 has an optical element. As shown in Fig. 10, an optical fiber 25 is connected to the light irradiation unit 12. The sample holder 9 has a mirror 14 as an optical element and a mounting unit (not shown) for mounting the optical fiber 25. The sample holder 9 may also have a plurality of optical elements other than the mirror 14, such as other mirrors or lenses.

[0069] The pulsed light 13 emitted from the light irradiation unit 12 is irradiated onto the first electrode unit 15 or the second electrode unit 18 via the optical fiber 25 and the mirror 14. That is, the pulsed light 13 passes through the inside of the optical fiber 25, is emitted from the optical fiber 25, is reflected and collected by the mirror 14, and is irradiated onto the first electrode unit 15 or the second electrode unit 18. Since the sample holder 9 has an optical element, equipment for installing the optical element in the charged particle beam device 100 can be omitted.

[0070] (Embodiment 3) A charged particle beam device 100 according to embodiment 3 will be described below with reference to Fig. 11. In the following description, differences from embodiment 1 will be mainly described, and descriptions of points that overlap with embodiment 1 will be omitted.

[0071] The charged particle beam device 100 in the third embodiment further includes an electron biprism. By using the electron biprism, a hologram 72 is acquired from the pulsed electron wave 2 that has transmitted through the sample 5. As shown in Fig. 11 , the electron biprism includes, for example, an electrode filament 70 and a parallel plate 71. The electrode filament 70 is installed between the observation surface 8 and the magnifying lens 7. The parallel plate 71 is electrically connected to the ground potential.

[0072] When a potential is applied to the electrode filament 70, an electric field is generated between the electrode filament 70 and the parallel plate 71. This electric field causes one side of the pulsed electron wave 2 that has passed through the sample 5 to be superimposed on the other side of the pulsed electron wave 2 that has not passed through the sample 5 on the observation surface 8. As a result, a hologram 72, which is an interference pattern of the pulsed electron wave 2, is generated on the observation surface 8. The hologram 72 is detected by the electron detector 53 and stored in the control PC 50.

[0073] When performing phase reconstruction in electron holography, the detected hologram 72 is analyzed by the Fourier transform method and is used to analyze the phase of the pulsed electron wave 2 that has passed through the sample 5. When a predetermined potential difference is generated in the sample 5, a local electric field or magnetic field is generated. From the amount of change in the detected hologram 72, the change in the local electric field or magnetic field can be measured with high time resolution.

[0074] Furthermore, in order to realize a more highly accurate phase analysis, for example, a double biprism method may be used by preparing a two-stage electron biprism.

[0075] Furthermore, the technology disclosed in the third embodiment can be applied in combination with the technology disclosed in the second embodiment.

[0076] (Fourth Embodiment) A charged particle beam device 100 according to a fourth embodiment will be described below with reference to Fig. 12. In the following description, differences from the first embodiment will be mainly described, and descriptions of points that overlap with the first embodiment will be omitted.

[0077] In the fourth embodiment, a differential phase contrast (DPC) method, which is a type of scanning transmission electron microscopy, is used. The scanning transmission electron microscopy is a technique in which a focused pulsed electron wave 2 is irradiated onto a sample 5, the irradiation position of the focused pulsed electron wave 2 is scanned using a deflection coil (not shown), and the electrons transmitted through the sample 5 are detected to obtain a secondary electron image.

[0078] The charged particle beam device 100 in the fourth embodiment includes, for example, an objective lens 80, a first projection lens 81, and a second projection lens 82. The objective lens 80 is provided between the first irradiation electron lens 3 and the sample 5. The first projection lens 81 and the second projection lens 82 are provided between the sample 5 and the observation surface 8.

[0079] A pulsed electron wave 2 is emitted from the electron beam irradiation unit 1, the convergence angle of the pulsed electron wave 2 is adjusted by the first irradiation electron lens 3 and the objective lens 80, and the converged pulsed electron wave 2 is irradiated onto the sample 5. The pulsed electron wave 2 that has passed through the sample 5 is magnified or reduced by the action of the first projection lens 81 and the second projection lens 82, and is detected by the electron detector 53 on the observation plane 8.

[0080] When an electric field or a magnetic field is present in the sample 5, the traveling direction of the pulsed electron wave 2 is deflected, and the position of the pulsed electron wave 2 detected by the electron detector 53 changes. When a predetermined potential difference is generated in the sample 5, a local electric field or magnetic field is generated. From the amount of change in the position where the pulsed electron wave 2 is detected, the change in the local electric field or magnetic field can be measured with high time resolution.

[0081] Furthermore, the technology disclosed in the fourth embodiment can be applied in combination with the technology disclosed in the second embodiment.

[0082] (Modification 1) A charged particle beam device 100 according to Modification 1 of the fourth embodiment will be described below with reference to FIG.

[0083] 13 , the charged particle beam device 100 in Modification 1 includes a secondary electron detector 83. A focused pulsed electron wave 2 is irradiated onto a sample 5, and the irradiation position of the focused pulsed electron wave 2 is scanned using a deflection coil (not shown). A secondary electron image is obtained by detecting secondary electrons generated from the sample 5 with the secondary electron detector 83. By using the secondary electron detector 83, it is possible to measure local changes in the amount of secondary electrons generated with high time resolution.

[0084] (Modification 2) A charged particle beam device 100 according to Modification 2 of the fourth embodiment will be described below with reference to FIG.

[0085] 14 , the charged particle beam device 100 in Modification 2 includes an energy dispersive X-ray spectrometer 84. A focused pulsed electron wave 2 is irradiated onto a sample 5, and the irradiation position of the focused pulsed electron wave 2 is scanned using a deflection coil (not shown). Characteristic X-rays are emitted from the sample 5 due to an interaction between the pulsed electron wave 2 irradiated onto the sample 5 and the sample 5. Elemental analysis of the sample 5 becomes possible by detecting the emitted characteristic X-rays with the energy dispersive X-ray spectrometer 84. Use of the energy dispersive X-ray spectrometer 84 makes it possible to measure local changes in the sample 5 with high time resolution.

[0086] Although not shown, the charged particle beam device 100 in Modification 2 may further include a cathodoluminescence detector. Measurement of optical properties using the cathodoluminescence detector and elemental analysis of the sample 5 using the energy dispersive X-ray spectrometer 84 may be combined.

[0087] (Modification 3) A charged particle beam device 100 according to Modification 3 of the fourth embodiment will be described below with reference to FIG.

[0088] 15 , the charged particle beam device 100 in Modification 3 includes an electron energy loss spectrometer 85. A narrowed pulsed electron wave 2 is irradiated onto a sample 5, and the irradiation position of the narrowed pulsed electron wave 2 is scanned using a deflection coil (not shown). Due to an interaction between the pulsed electron wave 2 irradiated onto the sample 5 and the sample 5, the pulsed electron wave 2 that passes through the sample 5 contains electrons having an energy different from the energy before passing through the sample 5. The pulsed electron wave 2 that has passed through the sample 5 is magnified or reduced by the action of a first projection lens 81 and a second projection lens 82, and is detected by the electron energy loss spectrometer 85.

[0089] When a predetermined potential difference is generated in the sample 5, the distribution of the chemical bonding states or the distribution of the density of states changes in the sample 5. By analyzing the energy distribution of the pulsed electron wave 2 using the electron energy loss spectrometer 85, the change in the distribution of the chemical bonding states or the distribution of the density of states in the sample 5 can be measured with high time resolution.

[0090] Fifth Embodiment A charged particle beam device 100 according to a fifth embodiment will be described below with reference to Fig. 16. In the following description, differences from the first embodiment will be mainly described, and descriptions of points that overlap with the first embodiment will be omitted.

[0091] 15 , the sample holder 9 in the fifth embodiment has a piezoelectric element 26. The first potential transmission unit 16 and the second potential transmission unit 19 are electrically connected to the piezoelectric element 26. The sample 5 is placed on the sample holder 9 so as to be in contact with the piezoelectric element 26 without being in direct contact with the first potential transmission unit 16 and the second potential transmission unit 19.

[0092] In the fifth embodiment, a potential difference is not generated directly in the sample 5, but is generated in the piezoelectric element 26. The potential difference is converted into stress by the piezoelectric element 26, and the stress is applied from the piezoelectric element 26 to the sample 5. At this time, a change in the arrangement of the sample 5 or the degree of cracking of the sample 5 can be measured with time resolution.

[0093] The potential difference may be converted into a magnetic field by replacing the piezoelectric element 26 with a multiferroic material. In this case, the first potential transmission unit 16 and the second potential transmission unit 19 are electrically connected to the multiferroic material. When the light irradiation unit 12 irradiates the first electrode unit 15 with pulsed light 13, a potential difference is generated in the multiferroic material, and the potential difference is converted into a magnetic field by the multiferroic material. A predetermined stress is applied to the sample 5 by this magnetic field.

[0094] The potential difference may be converted into an electrostatic field by replacing the piezoelectric element 26 with space. In this case, an electrostatic field is generated between the first potential transmission unit 16 and the second potential transmission unit 19 by irradiating the first electrode unit 15 with pulsed light 13 from the light irradiation unit 12. A predetermined stress is applied to the sample 5 by this electrostatic field.

[0095] Furthermore, the technology disclosed in the fifth embodiment can be applied in combination with the technologies disclosed in the second to fourth embodiments.

[0096] The present invention has been specifically described above based on the above embodiment, but the present invention is not limited to the above embodiment and can be modified in various ways without departing from the spirit of the present invention.

[0097] 100 Charged particle beam device 1 Electron beam irradiation unit (charged particle beam irradiation unit) 2 Pulsed electron wave (pulsed charged particle wave) 3 First irradiation electron lens 4 Second irradiation electron lens 5 Sample 5a Intended sample position 6 Objective lens 7 Magnifying lens 8 Observation surface 9 Sample holder 10 Conductive wire 11 Power supply 12 Light irradiation unit 13 Pulsed light 14 Mirror 15 First electrode unit 16 First potential transmission unit 17 Photoelectron emission 18 Second electrode unit 19 Second potential transmission unit 20 Third electrode unit 21 Fourth electrode unit 22 Potential difference measurement unit 23 MEMS chip 24 Hole 25 Optical fiber 26 Piezo element 30 Light irradiation possible area 31 Irradiation position and irradiation size 50 Control PC 51 Monitor 52 Control system 53 Electron detector 54 Housing 70 Electrode filament of electron biprism 71 Parallel plate of electron biprism 72 Hologram 80 Objective lens 81 First projection lens 82 Second projection lens 83 Secondary electron detector 84 Energy dispersive X-ray spectrometer 85 Electron energy loss spectrometer

Claims

1. A charged particle beam device comprising: a charged particle beam irradiation unit for irradiating a pulsed charged particle wave; a sample holder for placing a sample; and a light irradiation unit for irradiating pulsed light, wherein the sample holder has an electrode unit, a first potential transmission unit connected to the electrode unit, and a second potential transmission unit, wherein when the sample is placed on the sample holder, the sample is electrically connected to the first potential transmission unit and the second potential transmission unit, and a predetermined potential difference is generated in the sample by irradiating the electrode unit with the pulsed light from the light irradiation unit, and the pulsed charged particle wave is irradiated from the charged particle beam irradiation unit to the sample while synchronizing the period of irradiation of the pulsed light and the period of irradiation of the pulsed charged particle wave.

2. A charged particle beam device according to claim 1, wherein the sample holder further comprises a MEMS chip, the electrode portion, the first potential transmission portion and the second potential transmission portion are provided on the MEMS chip, and the sample is placed on the MEMS chip.

3. A charged particle beam device according to claim 1, wherein the sample holder further has a potential difference measuring unit for measuring the potential difference occurring in the sample, and the potential difference measuring unit has a third electrode unit electrically connected to the first potential transmission unit and a fourth electrode unit electrically connected to the second potential transmission unit.

4. A charged particle beam device according to claim 3, wherein the irradiation position of the pulsed light and the size of the pulsed light are adjusted before the pulsed light is irradiated onto the electrode portion.

5. A charged particle beam device according to claim 4, wherein, before irradiating the electrode unit with the pulsed light, relationship information between the irradiation intensity of the pulsed light and the potential difference generated in the potential difference measuring unit is obtained by calculating using the minimum and maximum values ​​of the irradiation intensity of the pulsed light, the acceleration voltage of the pulsed charged particle wave, and the shape and dimensions of the potential difference measuring unit, and after adjusting the irradiation intensity of the pulsed light from the light irradiating unit, the electrode unit is irradiated with the pulsed light.

6. A charged particle beam device according to claim 1, wherein the timing of irradiating the electrode with the pulsed charged particle wave is changed multiple times relative to the timing of irradiating the sample with the pulsed light, thereby making it possible to obtain observation data of the sample with time resolution for multiple times.

7. A charged particle beam device according to claim 6, wherein the pulsed light is irradiated from the light irradiation unit to the electrode unit so that the potential difference generated in the sample changes continuously over time during one period of irradiation of the pulsed light.

8. A charged particle beam device according to claim 1, further comprising an optical fiber, wherein the sample holder further comprises an optical element, and wherein the pulsed light emitted from the light irradiation unit is irradiated onto the electrode unit via the optical fiber and the optical element.

9. A charged particle beam device according to claim 1, further comprising an electron beam birefringence, wherein the electron beam birefringence is used to obtain a hologram from the pulsed charged particle wave that has passed through the sample.

10. A charged particle beam device according to claim 1, wherein the focused pulsed charged particle wave is irradiated onto the sample, and the irradiation position of the focused pulsed charged particle wave is scanned.

11. A charged particle beam device comprising: a charged particle beam irradiation unit for irradiating a sample with a pulsed charged particle wave; a sample holder for placing the sample; and a light irradiation unit for irradiating the electrode unit with pulsed light, wherein the sample holder has an electrode unit, a first potential transmission unit connected to the electrode unit, and a second potential transmission unit, wherein when the sample is placed on the sample holder, the sample is not in direct contact with the first potential transmission unit and the second potential transmission unit, and a predetermined stress is generated in the sample by irradiating the electrode unit with the pulsed light from the light irradiation unit, and the pulsed charged particle wave is irradiated from the charged particle beam irradiation unit to the sample while synchronizing the period of irradiation of the pulsed light and the period of irradiation of the pulsed charged particle wave.

12. A charged particle beam device according to claim 11, wherein the sample holder further has a piezoelectric element, the first potential transmission unit and the second potential transmission unit are electrically connected to the piezoelectric element, and when the pulsed light is irradiated from the light irradiation unit to the electrode unit, a potential difference is generated in the piezoelectric element, and the predetermined stress is applied from the piezoelectric element to the sample.

13. A charged particle beam device according to claim 11, wherein the sample holder further comprises a multiferroic material, the first potential transmission unit and the second potential transmission unit are electrically connected to the multiferroic material, and when the pulsed light is irradiated from the light irradiation unit to the electrode unit, a potential difference is generated in the multiferroic material, the potential difference is converted into a magnetic field by the multiferroic material, and the predetermined stress is applied to the sample by the magnetic field.

14. A charged particle beam device as described in claim 11, wherein an electrostatic field is generated between the first potential transmission unit and the second potential transmission unit by irradiating the pulsed light from the light irradiation unit to the electrode unit, and the predetermined stress is applied to the sample by the electrostatic field.

15. A sample observation method for obtaining time-resolved observation data of a sample using a charged particle beam irradiation unit for irradiating a pulsed charged particle wave, a sample holder having an electrode unit, a first potential transmission unit and a second potential transmission unit connected to the electrode unit, and a light irradiation unit for irradiating pulsed light, wherein when the sample is placed on the sample holder, the sample is electrically connected to the first potential transmission unit and the second potential transmission unit, and a predetermined potential difference is generated in the sample by irradiating the electrode unit with the pulsed light from the light irradiation unit, and the charged particle beam irradiation unit irradiates the sample with the pulsed charged particle wave while synchronizing the period of irradiation of the pulsed light and the period of irradiation of the pulsed charged particle wave, thereby obtaining time-resolved observation data of the sample using a charged particle beam device.

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