JP2009121841A - Combined electron spectrometer and electron spectroscopy method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron spectrometer and an electron spectroscopy method for easily obtaining accurate information on an electron structure and a local structure of the chemical species for forming a surface or an interface of a single-layer or multi-layer solid sample. <P>SOLUTION: The electron spectrometer is provided with: a vacuum vessel 11; a sample holding section 13a for holding the sample 12 within the vacuum vessel 11; an X ray source 31 disposed in a position of the vacuum vessel 11 in which a measurement point 12b of the sample 12 is viewed, and irradiating the measurement point 12b with X rays; an ultraviolet ray source 32 for irradiating it with ultraviolet rays; a plurality of electron beam sources 33 for irradiating electron beams; and an electron energy analyzer 40 for detecting photoelectrons emitted from the sample 12 by irradiating it with the X rays, the ultraviolet rays or the electron beams, or electrons scattered by the sample 12. A plurality of the electron beam sources 33, 33, ... are disposed so as to cause incident angles of the electron beams to be different relative to a sample surface 12a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electron spectroscopic analysis composite apparatus and an electron spectroscopic analysis method for obtaining information on the electronic structure and local structure of a chemical species forming the surface or interface of a single-layer or multilayer solid sample with high accuracy.

  Conventionally, methods for analyzing the surface or interface of a single-layer or multilayer solid sample (hereinafter simply referred to as “sample”) include electron energy loss spectroscopy (EELS), X-ray photoelectron spectroscopy (XPS), and ultraviolet light. An analysis method using spectroscopy such as photoelectron spectroscopy (UPS) is known. By analyzing each data obtained from these spectroscopic methods, information such as an electronic structure and a local structure described later on the surface or interface of the sample can be obtained.

  Depending on the EELS, XPS and UPS, different shell electron states in atoms or molecules can be obtained, respectively. Specifically, EELS means that a monochromatic electron beam is irradiated onto a measurement point on a sample surface, and electrons transmitted through the sample or inelastically scattered electrons on the sample surface are detected. Be analyzed. In this way, information on the sample surface can be obtained by detecting a loss of energy characteristic of the chemical bonding state of a certain element. In particular, a method of spectrally analyzing the energy of the scattered electrons (hereinafter also referred to as “scattered electrons”) is called REELS.

  The spectrum obtained from the EELS includes structural information on the atomic and molecular scales as in the X-ray absorption fine structure (XAFS). Therefore, information on the local structure such as the atomic species coordinated with a certain analysis element constituting the sample surface, the coordination number, the distance to the coordination atom, and the three-dimensional structure, the electronic state of the conduction band, etc. can be obtained. . The EELS includes REELS.

  Further, information on the band gap and the electron density of the film can be obtained from the plasmon loss peak appearing in the spectrum obtained from EELS. This plasmon loss peak appears when energy is lost due to collective motion (plasma oscillation) of electrons occurring at the valence band level.

  XPS and UPS are both types of photoelectron spectroscopy. In photoelectron spectroscopy, when an electromagnetic wave is irradiated from an excitation source to a measurement point on the sample surface, photoelectrons having specific kinetic energy corresponding to the chemical state or bonding state of an element are emitted from the sample surface by the photoelectric effect. . In this way, the photoelectrons emitted in this manner are detected and subjected to spectroscopic analysis to obtain information on the sample surface. In such photoelectron spectroscopy, the one using X-rays as an excitation source is XPS, and the one using ultraviolet rays as an excitation source is UPS. From these XPS and UPS, information on the chemical bond species of each element constituting the sample surface, the valence, the electronic state of the valence band reflecting the surface state of the sample, the work function, and the like can be obtained.

  The sample surface analysis by each spectroscopic method such as EELS, XPS, and UPS may be performed on the same sample (see Non-Patent Document 1).

  Furthermore, in order to obtain not only information on the surface of the sample but also information on the inside of the sample, for example, information on the interface in the sample composed of multiple layers, an analyzer using REELS that can change the incident angle of the electron beam to the sample surface ( Hereinafter, simply referred to as “REELS analyzer” has been developed (see Patent Document 1). Like this analyzer, the incident angle of the electron beam with respect to the sample surface changes, so that the incident depth of the electron beam incident on the inside from the sample surface changes corresponding to the incident angle. Therefore, according to this analyzer, information on the electronic structure or local structure inside the sample according to the incident depth of the electron beam can be obtained.

Also, an electron gun that can change the incident angle of the electron beam to the sample surface without changing the measurement point that is the electron beam irradiation position on the sample surface, and an electron that can change the detection angle of scattered electrons scattered on the sample surface A REELS analyzer including an energy analyzer has also been developed (see Patent Document 2). According to this analyzer, not only unidirectional structural information but also omnidirectional structural information can be obtained among atoms existing around inelastically scattered atoms.
JOURNAL OF APPLIED PHYSICS 99, 044911 (2006) JP-A-63-190239 JP-A-5-332959

By the way, in order to obtain highly accurate information such as the electronic structure and local structure of chemical species that form the surface or interface of a single-layer or multi-layer sample, not only the analysis of the sample by a single spectroscopic method but also multiple spectroscopy. Analysis by law is required. For example, in order to examine the electronic structure of the surface of a Nb ₂ N thin film or NbN thin film, it is generally measured by XPS. At that time, as shown in Non-Patent Document 1, the measurement is further performed by spectroscopy such as UPS and EELS, and each information obtained by the plurality of spectroscopy is analyzed, whereby the electron on the surface of the sample is analyzed. Information such as structure can be obtained with higher accuracy.

  However, the conventional analyzer is an X-ray photoelectron spectroscopic analyzer for XPS analysis, an ultraviolet photoelectron spectroscopic analyzer for UPS, a REELS analyzer described in Patent Document 1 for obtaining interface information, etc. Thus, there was only a separate device for each spectroscopic method and measurement purpose. Therefore, in order to obtain highly accurate information such as the electronic structure on the surface of the sample, measurement and analysis by each spectroscopic method and the like must be individually performed by each analyzer.

  In this case, it is necessary to move the sample between the analyzers. Therefore, the working time, for example, the total time for taking out and moving the sample from one analyzer, introduction to other analyzers, adjustment, etc. will increase, and the measurement point shifts when set in each analyzer In addition, the sample surface is contaminated by the air that is moving between the analyzers. As a result, the obtained data for each analytical device is obtained as individual data having respective environments, conditions, and device functions (see the shape of each spectrum in FIG. 5). However, due to the displacement of the measurement points and the contamination of the sample surface as described above, each data is combined into one, that is, the spectra in FIG. There has been a problem that information such as the electronic structure of the specified measurement point on the interface cannot be comprehensively evaluated, or becomes extremely difficult and complicated.

  Further, in the analyzers described in Documents 1 and 2 as described above, the incident angle of the electron beam and the electron detection angle are moved in order to obtain information on the target electronic structure and local structure of the sample. There is a need. Therefore, a predetermined time is required for the electron gun or the like to be moved to a predetermined position. In addition, when the electron beam is incident on the sample again at the same incident angle, it is very difficult to ensure the reproducibility of the incident angle. Therefore, there is a possibility that problems such as inconvenience in operation and measurement of the analyzer become very complicated and difficult and inefficient.

  In view of the above problems, the present invention provides an electron spectroscopic analysis that can easily obtain highly accurate information such as the electronic structure and local structure of a chemical species that forms the surface or interface of a single-layer or multilayer solid sample. It is an object to provide an apparatus and an electron spectroscopic analysis method.

  In order to solve the above problems, an electron spectroscopic analysis composite apparatus according to the present invention includes a vacuum vessel, a sample holding unit for holding a sample in the vacuum vessel, and the sample holding unit in the vacuum vessel. An X-ray source that is arranged at a position facing a measurement point of a sample to be held, irradiates the measurement point with X-rays, an ultraviolet ray source that irradiates ultraviolet rays, and a plurality of electron beam sources that irradiate electron beams; An electron energy analyzer for detecting photoelectrons emitted from the sample by being irradiated with ultraviolet rays or an electron beam or electrons scattered by the sample, and the plurality of electron beam sources with respect to the surface of the sample. It is characterized in that the incident angles of electron beams are different from each other.

  According to such a configuration, each measurement and analysis by XPS, UPS, and EELS (including REELS) is performed in a state where the sample is held in the sample holding unit, and therefore work when moving the sample between analyzers There is no increase in time or deviation of measurement points in each measurement. Furthermore, since each measurement is performed in the same vacuum vessel, the sample is not exposed to the atmosphere. Therefore, the sample is not polluted by the atmosphere. Therefore, the data obtained by each measurement method can be comprehensively evaluated, and various highly accurate information such as the electronic structure and local structure of the surface or interface of the sample, the electronic state, the work function, and the band gap can be obtained.

  Further, a plurality of electron beams can be sequentially irradiated at different incident angles with respect to the measurement point on the sample surface without moving the electron beam source. Therefore, when obtaining the structural information of the sample at the incident depth corresponding to the incident angle of the electron beam, it is not necessary to move the electron beam source to a predetermined position. Furthermore, since the electron beam source is configured not to move when the electron beam is incident again at the same incident angle, it is extremely easy to ensure the reproducibility of the incident angle.

  In addition, since photoelectrons and scattered electrons can be detected by a single electron energy analyzer, the apparatus can be reduced in size and cost.

  The plurality of electron beam sources includes two electron beams: a vertical electron beam source that irradiates the surface of the sample with an electron beam from a vertical direction and a low angle electron beam source that irradiates an electron beam from a low angle. The electron energy analyzer is opposed to the low-angle electron beam source across the sample, and the detection angle corresponds to the incident angle of the electron beam from the low-angle electron beam source with respect to the surface of the sample The structure arrange | positioned in the position which becomes an angle to do may be sufficient.

  With such a configuration, information such as the electronic structure between the sample surface and the inside of the sample can be obtained with two electron beam sources. That is, information such as the electronic structure at a depth position that varies greatly from the sample surface toward the inside can be obtained. As a result, the number of electron beam sources can be reduced, and the structure of the analyzer can be simplified and the cost can be reduced. In the present invention, the low angle refers to an angle at which electrons constituting the irradiated electron beam are scattered in several atomic layers on the surface of the sample while hardly entering the sample.

  In addition, when an electron beam is irradiated on the sample surface from a low angle, the yield of scattered electrons by the electron beam, that is, the inelastically scattered electrons by the sample surface is very small. Therefore, the electron energy analyzer has an angle corresponding to the irradiation angle of the low-angle electron beam source with respect to the sample surface, that is, the irradiated electron beam is regularly reflected at the measurement point of the sample (for example, an incident angle and By detecting the scattered electrons in the vicinity of the orbit when the reflection angle is the same, the scattered electrons can be detected efficiently.

  The electron beam source may be a scanning electron gun.

  According to such a configuration, a predetermined region including the measurement point on the sample surface is scanned with an electron beam with a predetermined acceleration voltage. At that time, loss of electron energy occurs due to atoms having a characteristic in the target energy, a bonding state, or the like in the scanned region. In the region, the electron energy analyzer detects the measurement point where the loss of the electron energy has occurred due to atoms, bonding state, etc. and the change in the yield of scattered electrons including the energy loss, and the scanning and the yield are synchronized. Thus, a distribution map for each chemical state in the region can be obtained.

  Further, the low-angle electron beam source may be arranged so that an incident angle of the electron beam with respect to the surface of the sample is 10 ° to 15 °.

  According to such a configuration, scattered electrons scattered on the sample surface are efficiently emitted. For this reason, it is easy to obtain information such as the electronic structure of several atomic layers on the sample surface.

  The secondary electron detector that detects secondary electrons emitted from the sample by the electron beam irradiated from the vertical electron beam source may be further provided at a position facing the measurement point of the sample. .

  According to such a configuration, an image of the sample surface at the measurement point of the sample can be obtained based on the secondary electrons detected by the secondary electron detector, and the state of the sample surface can be obtained as visual information. .

  Further, each spectrum based on the photoelectrons or scattered electrons detected by the electron energy analyzer is combined in energy by irradiating the sample from each excitation source of the X-ray source, ultraviolet ray source and electron beam source. A spectrum measurement means capable of producing one continuous spectrum, the spectrum measurement means being a common correction function (device function) for obtaining each spectrum based on the detected photoelectrons or scattered electrons It can be set as the structure which has these.

  According to such a configuration, each spectrum obtained individually by irradiation of the sample by each excitation source can be combined in energy, and one continuous spectrum is obtained. That is, each spectrum obtained by measurement at each excitation source is formed by the spectrum measuring means using a common correction function (device function) related to energy. Therefore, the respective spectra are easily combined as one spectrum without considering the difference in the correction function (device function) related to energy.

  Furthermore, based on the one continuous spectrum obtained in this way, data obtained by measurement with each light source can be comprehensively evaluated. That is, measurement by each excitation source is performed without moving the measurement point of the sample while being held by the sample holding unit in the same vacuum container. Therefore, similarly to the above, there is no displacement of the measurement point in the measurement with each excitation source and no contamination of the sample surface by the atmosphere. Therefore, it is possible to comprehensively evaluate the measurement at each excitation source based on the obtained one continuous spectrum without considering the problems such as the deviation and contamination.

  In addition, a posture control means for controlling the posture of the sample holding portion is further provided, and the posture control means holds the sample without changing the relative position between the measurement point of the sample held in the sample holding portion and the vacuum vessel. The X-ray source and the ultraviolet ray source are arranged closer to the electron energy analyzer in the direction connecting the electron energy analyzer and the low-angle electron beam source than the measurement point of the sample. It may be configured.

  According to such a configuration, even if the posture of the sample holder is changed by the posture control means, the posture of the sample surface is perpendicular to the direction connecting the measurement point of the sample surface and the electron energy analyzer. The X-ray source (or ultraviolet light source) can irradiate the measurement point of the sample with X-rays (or ultraviolet light). Therefore, photoelectrons emitted from the sample surface are efficiently detected by the electron energy analyzer, and information such as the electronic structure of the sample surface can be obtained in more detail.

  An ion gun that irradiates an ion beam to perform sputter etching on the measurement point of the sample faces the measurement point of the sample, and electrons in a direction connecting the electron energy analyzer and the low-angle electron beam source. The structure further provided in the energy analyzer side may be sufficient.

  According to such a configuration, sputter etching in the vicinity of the measurement point of the sample is possible even when the sample holder changes the posture as described above when X-rays or ultraviolet rays are irradiated. Therefore, in addition to the composition distribution in the depth direction of the sample, information such as the electronic structure in the depth direction can be obtained with high accuracy.

  Furthermore, even if the sample holder changes its posture as described above, it is possible to remove contaminants and oxide films on the sample surface, so that the information can be obtained with higher accuracy and detail.

  In addition, the sample holder may be configured to include at least one of a heating unit and a cooling unit for heating or cooling the sample.

  According to this configuration, since the sample can be heated or cooled, information such as the electronic structure on the surface and the like can be obtained for the sample after being heated or cooled in the vacuum vessel.

  Further, in order to solve the above problem, the composite electron spectroscopic analysis method according to the present invention introduces a sample into a vacuum vessel and arranges the measurement point of the sample to be a predetermined position in the vacuum vessel. After individually irradiating the measurement point of the sample with X-rays and ultraviolet rays, the same measurement point is irradiated with an electron beam in order from a plurality of directions, and the irradiated X-rays, ultraviolet rays or electron beams are emitted from the sample. The emitted photoelectrons or the electrons scattered by the sample are detected by the same electron energy analyzer, respectively.

  According to such a configuration, since the same measurement point of the sample is sequentially irradiated by each excitation source without moving the measurement point of the sample from a predetermined position in the same vacuum vessel, it is moved between the analyzers as described above. Therefore, there is no increase in work time and no shift in measurement points. Further, since the sample does not come into contact with the atmosphere, the sample is not contaminated by the atmosphere. Therefore, each data detected (obtained) by irradiation of each excitation source is comprehensively evaluated, and various data such as an electronic structure on the surface of the sample are obtained.

  At this time, since an electron beam having a large interaction with atoms is irradiated after irradiation of X-rays and ultraviolet rays, it is not necessary to consider damage to the sample surface by the electron beam with respect to the obtained data. Therefore, highly accurate and detailed information such as the electronic structure on the surface of the sample can be easily obtained.

  Further, in order to obtain structural information of the sample having an incident depth corresponding to the incident angle of the electron beam, the electron beam can be irradiated at a different incident angle with respect to the measurement point on the sample surface without moving the irradiation direction of the electron beam. Therefore, there is no need for time for moving the electron beam irradiation direction. Furthermore, it is very easy to ensure the reproducibility of the incident angle when the electron beam is incident again at the same incident angle.

  In addition, since the photoelectrons or scattered electrons are detected by the same electron energy analyzer, measurement (analysis) is easily performed and cost reduction is achieved.

  Further, the electron beam irradiated from the plurality of directions is from two directions that are irradiated in order from either the vertical electron beam irradiated from the vertical direction or the low angle electron beam irradiated from a low angle to the surface of the sample. The electron energy at a position opposite to the irradiation position of the low-angle electron beam across the sample and at an angle corresponding to the incident angle of the low-angle electron beam with respect to the surface of the sample. The analyzer may be configured to detect each electron scattered by the sample.

  According to such a configuration, information such as the electronic structure between the sample surface and the inside of the sample can be obtained by two electron beam irradiations. That is, information such as the electronic structure at a depth position that varies greatly from the sample surface toward the inside can be obtained. As a result, the number of times of electron beam irradiation can be reduced, and the procedure can be simplified and the cost can be reduced.

  Moreover, when an electron beam is irradiated on the sample surface from a low angle, the yield of inelastically scattered electrons by the electron beam is very small. Therefore, in the same manner as described above, the electron energy analysis is performed in order to emit scattered electrons near the orbit when the irradiated electron beam is specularly reflected at the measurement point (for example, reflection with the same incident angle and reflection angle). The detector can detect the scattered electrons efficiently.

  Moreover, after irradiating an ultraviolet-ray and X-ray in order, the structure which irradiates a low-angle electron beam or a vertical electron beam in order from either one may be sufficient.

  According to such a configuration, after the sample surface is measured with ultraviolet rays, information such as the electronic structure of an energy level deeper than the ultraviolet rays is measured by X-rays. Thereafter, information such as an electronic structure is further measured with an electron beam which is a particle beam. By irradiating in this order, damage to the sample due to each previously irradiated excitation line is sufficiently suppressed. Therefore, by irradiating each excitation line in the above order, damage to the sample is suppressed, and highly accurate and detailed information such as the electronic structure on the surface of the sample can be obtained.

  As described above, according to the present invention, an electronic spectroscopic analysis composite apparatus capable of easily obtaining highly accurate information such as the electronic structure and local structure of a chemical species that forms the surface or interface of a single-layer or multilayer solid sample, and An electron spectroscopic analysis method can be provided.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  As shown in FIGS. 1 to 3, an electron spectroscopic analysis composite apparatus (hereinafter, also simply referred to as “analysis apparatus”) 10 includes a single-layer or multilayer solid sample (hereinafter simply referred to as “sample”) in a vacuum vessel 11. The sample holder 13a for holding 12), a plurality of excitation sources 30 for irradiating the held sample 12 with electromagnetic waves or electron beams, and the sample by the irradiation from the excitation source 30. And an electron energy analyzer 40 for detecting electrons emitted from 12 (photoelectrons) or electrons scattered by the sample 12 (scattered electrons). The analysis apparatus 10 configured as described above is based on the photoelectrons or scattered electrons detected by the electron energy analyzer 40 and provides high-precision information such as the electronic structure and local structure of the chemical species that form the surface or interface of the sample 12. Can be obtained.

  Hereinafter, the analyzer 10 will be described in detail. The vacuum vessel 11 is a so-called vacuum chamber formed in a hollow spherical shape, and includes a vacuum exhaust system (not shown) for exhausting the inside of the vacuum vessel 11 to make an ultra-high vacuum.

  The stage (sample holding unit) 13 a is for placing and holding the sample 12, and is arranged at the center of the vacuum vessel 11. The stage 13a constitutes a manipulator 13 together with a posture control means 13b for controlling the posture of the stage 13a.

  More specifically, the stage 13 a is arranged so that the measurement point 12 b of the sample 12 is positioned at the center of the vacuum vessel 11 when the sample 12 is held. The posture control means 13b connected to the stage 13a and controlling the posture is configured so that the posture of the stage 13a can be changed without changing the relative position between the measurement point 12b of the sample 12 and the vacuum vessel 11. That is, the posture control means 13b can change the posture of the stage 13a in a state where the measurement point 12b of the sample 12 held on the stage 13a is always located at the center of the vacuum vessel 11. The stage 13 a further includes at least one of a heating unit or a cooling unit for heating or cooling the sample 12. In the present embodiment, the stage 13 a includes a heating / cooling device 13 c that can heat and cool the held sample 12.

  The plurality of excitation sources 30 are for irradiating the measurement point 12b of the sample surface 12a held by the stage 13a with electromagnetic waves or electron beams. The plurality of excitation sources 30 includes an X-ray source 31 that irradiates X-rays, an ultraviolet source 32 that irradiates ultraviolet rays, and a plurality of electron beam sources 33, 33,. Each of these excitation sources 31, 32, and 33 is disposed at a position facing the measurement point 12b of the vacuum vessel 11 so that the measurement point 12b of the sample 12 can be irradiated with electromagnetic waves (X-rays or ultraviolet rays) or an electron beam. Further, the plurality of electron beam sources 33, 33,... Are arranged at positions where the incident angles of the electron beams irradiated from the respective electron beam sources with respect to the sample surface 12a are different.

  In the present embodiment, the plurality of electron beam sources 33 includes two electron beam sources 33 and 33. When the posture of the stage 13a is set so that the sample surface 12a is along the horizontal direction (see FIG. 2 or FIG. 3), one electron beam source 33a is at a low angle (close to horizontal) with respect to the sample surface 12a. This is a low-angle electron beam source 33a disposed in the vacuum vessel 11 so as to irradiate an electron beam from an angle. In the present embodiment, the low angle refers to an angle at which the electrons constituting the irradiated electron beam are scattered on the sample surface 12a with almost no incident on the inside of the sample 12. Specifically, it is about 0 ° to 30 ° with respect to the surface of the sample 12. In the present embodiment, the low-angle electron beam source 33a takes into account the three-dimensional structure of the low-angle electron beam source 33a, so that the incident angle of the electron beam with respect to the sample surface 12a is 10 ° to more close to the measurement point. It arrange | positions in the vacuum vessel 11 so that it may become 15 degrees (refer (alpha) in FIG. 3). The other electron beam source 33 is a vertical electron beam source 33b disposed in the vacuum container 11 so as to irradiate the sample surface 12a with an electron beam from the vertical direction. These two electron beam sources 33a and 33b are both constituted by a scanning electron gun.

  In this embodiment, the electron energy analyzer 40 is configured not only to detect photoelectrons or scattered electrons but also to perform analysis based on the detected photoelectrons or scattered electrons and to output various data such as spectrum waveforms. Has been. This electron energy analyzer 40 is opposed to the low-angle electron beam source 33a in the vacuum vessel 11 with the sample 12 (measurement point 12b) in between, and the detection angle is an electron from the low-angle electron beam source 33a with respect to the sample surface 12a. It is arranged at a position where the angle corresponds to the incident angle of the line.

  That is, when the apparatus 10 is viewed from the plane direction, the electron energy analyzer 40, the sample 12, and the low-angle electron beam source 33a are disposed on the same straight line. In addition, in the vertical cross section passing through the same straight line, the electron energy analyzer 40 is slightly different from the trajectory of the electron beam when the electron beam irradiated from the low-angle electron beam source 33a is regularly reflected at the measurement point 12b of the sample 12. It is arranged at a position shifted to. This is because the electron energy analyzer 40 (more specifically, the detection unit of the electron energy analyzer 40) is positioned on the regular reflection orbit of the electron beam, that is, the detection angle is the same as the incident angle of the electron beam. This is because there is a possibility that the amount of scattered electrons emitted from the measurement point reaching the electron energy analyzer 40 is too large to be detected.

  The X-ray source 31 and the ultraviolet light source 32 are not particularly limited in position as long as they are positions that do not hinder the arrangement of other components in the vacuum vessel 11 and face the measurement point 12b of the sample 12. The That is, in the present embodiment, the X-ray source 31 and the ultraviolet ray source 32 are the manipulator 13, the low-angle electron beam source 33a, the vertical electron beam source 33b, the electron energy analyzer 40, and the sample introduction described later in the vacuum vessel 11. It is arranged at a position where the measurement point 12b can be irradiated with X-rays or ultraviolet rays without disturbing the arrangement and operation of the machine 14.

  Preferably, the position is such that photoelectrons emitted from the sample 12 by irradiation with X-rays or ultraviolet rays efficiently reach the electron energy analyzer 40. Specifically, the arrangement positions of the X-ray source 31 and the ultraviolet ray source 32 are closer to the electron energy analyzer 40 side in the direction connecting the electron energy analyzer 40 and the low-angle electron beam source 33a than the measurement point 12b of the sample 12. It is a position. That is, when the posture of the stage 13a is changed by the posture control means 13b so that the sample surface 12a has a posture orthogonal to the direction connecting the measurement point 12b of the sample surface 12a and the electron energy analyzer 40, The position is such that the X-ray source 31 (or ultraviolet light source 32) can irradiate the measurement point 12b of the sample 12 with X-rays (or ultraviolet light).

  In the present embodiment, the angle formed by the line connecting the measurement point 12b of the sample 12 from the X-ray source 31 (or the ultraviolet ray source 32) and the line connecting the measurement point 12b of the sample 12 and the electron energy analyzer 40 is the emission. Considering that many photoelectrons to be detected are detected, the angle is 50 ° to 60 °, and more preferably 55 °. If the angle is smaller than 50 °, the tip of the X-ray source 31 (or the ultraviolet ray source 32) may come into contact with the sample surface 12a. In order to avoid this contact, the X-ray (or ultraviolet ray) exit port. When the distance (working distance) to the sample surface 12a is increased, there is a problem that the intensity of X-rays (or ultraviolet rays) is insufficient. If the angle is greater than 60 °, the X-ray source 31 (or the ultraviolet ray source 32) may come into contact with the electron energy analyzer 40. If the working distance is increased to avoid this contact, the X-ray source is the same as above. This is because the problem of insufficient (or ultraviolet) intensity occurs.

  In the present embodiment, the analysis apparatus 10 further includes a sample introduction machine 14, an ion gun 15, a neutralization gun 16, and a secondary electron detector 17.

  The sample introduction machine 14 is for introducing the sample 12 to the stage 13 a from the outside of the vacuum vessel 11. The sample introduction machine 14 includes a front chamber 14a composed of an airtight chamber that can be evacuated, and a gate valve 14b that can keep the inside of the vacuum chamber 11 and the front chamber 14a airtight. The gate valve 14b is disposed closer to the vacuum container 11 than the front chamber 14a. Further, a vacuum exhaust system (not shown) for exhausting the inside is connected to the front chamber 14a. The sample introduction machine 14 is not particularly limited as long as it is a position in the vacuum vessel 11 where the sample 12 can be placed on the stage 13a. In the present embodiment, the sample introduction machine 14 is arranged so as to be positioned on the same horizontal plane as the stage 13a so that even the sample 12 that is inconvenient when tilted can be easily placed on the stage 13a.

  The ion gun 15 irradiates an ion beam for performing sputter etching on the measurement point 12b of the sample 12 and its vicinity. Further, the neutralizing gun 16 irradiates an ion beam for neutralizing the charging at the measurement point 12b of the sample 12 and the vicinity thereof. These ion gun 15 and neutralizing gun 16 are provided in the vacuum vessel 11 with each excitation source (X-ray source 31, ultraviolet source 32 and electron beam source 33) 30, electron energy analyzer 40, manipulator 13 and sample introduction machine 14. Is arranged at a position where the ion beam can be irradiated to the measurement point 12b without hindering the arrangement and operation of.

  In the ion gun 15 of the present embodiment, the stage is controlled by the attitude control means 13b so that the sample surface 12a is in an attitude orthogonal to the direction connecting the measurement point 12b of the sample surface 12a and the electron energy analyzer 40. This is a position where the ion beam of the ion gun 15 can be irradiated to the measurement point 12b of the sample when the posture of 13a is changed. Further, a position where the irradiation angle of the ion beam of the ion gun 15 with respect to the sample surface 12a becomes a high angle (closer to the orthogonal direction) is more preferable. This is because the irradiation area of the ion beam is suppressed on the sample surface 12a as the irradiation angle becomes higher for the same ion beam.

  The secondary electron detector 17 is for detecting secondary electrons emitted from the sample 12 by the electron beam irradiated from the vertical electron beam source 33b. This secondary electron detector 17 does not hinder the arrangement and operation of each excitation source 30, electron energy analyzer 40, manipulator 13, sample introduction machine 14, ion gun 15 and neutralizing gun 16 in the vacuum vessel 11, The secondary electron emitted from the sample 12 is arranged at a position where it can be detected efficiently. Note that the secondary electron detector 17 can change the detection efficiency by changing the posture of the stage 13a. Therefore, in the present embodiment, the sample 12 is inclined by 45 ° with respect to the horizontal plane. In order to obtain high strength efficiently, it is arranged at a low angle (0 °) with respect to the horizontal plane.

  Moreover, the analyzer 10 is provided with a spectrum measuring means (not shown). Each spectrum obtained by the spectrum measuring means based on the photoelectrons or scattered electrons detected by the electron energy analyzer 40 by irradiation of the sample 12 from each excitation source 31, 32, 33 is coupled in energy. It becomes a spectrum that can be. This is because the spectrum measuring means has an inherent correction function (device function), so that each spectrum based on the photoelectrons or scattered electrons detected by the electron energy analyzer 40 has the same correction function. This is because the spectrum is affected. Therefore, a continuous spectrum can be formed from each spectrum corresponding to each excitation source 31, 32, 33 obtained by the spectrum measuring means (see FIG. 4). The spectrum created in this way is output by output means (not shown) such as a monitor or a printer. In addition, each spectrum may be individually output as it analyzed with the conventional separate analyzer, without couple | bonding with a continuous spectrum (refer FIG. 5).

  The electron spectroscopic analysis composite apparatus 10 according to the present embodiment has the above configuration. Next, a measurement (analysis) method of the electron spectroscopic analysis composite apparatus 10 will be described.

  First, evacuation, so-called evacuation is performed by an evacuation system connected to the inside of the vacuum vessel 11, and an ultra-high vacuum state is obtained. In this state, the sample 12 is introduced onto the stage 13 a from the outside of the vacuum vessel 11 by the sample introduction machine 14. At this time, in the sample introduction machine 14, the sample 12 is carried into the front chamber 14a, and is evacuated by the connected vacuum exhaust system until the inside of the front chamber 14a reaches a high vacuum level. Thereafter, the gate valve 14b that partitions the front chamber 14a and the inside of the vacuum vessel 11 is opened, and the front chamber 14a and the inside of the vacuum vessel 11 communicate with each other. In this state, the sample introduction machine 14 places the sample 12 in the front chamber 14a on the stage 13a.

  Next, if necessary, the ion gun 15 is operated to irradiate the sample surface 12a with the ion beam. Thereby, the contaminants and oxide film on the sample surface 12a are uniformly etched and removed.

  Then, the sample 12 is irradiated with an electromagnetic wave or an electron beam from each excitation source 30. Specifically, first, the ultraviolet ray source 32 is operated to irradiate the sample 12 (measurement point 12b) with ultraviolet rays. The electron energy analyzer 40 detects and analyzes the photoelectrons emitted from the sample 12 by this ultraviolet irradiation. In this way, UPS spectrum data is obtained from the electron energy analyzer 40. Further, when the sample 12 is irradiated with ultraviolet rays, the manipulator 13 is operated, and the posture of the stage 13a is changed so that the electron energy analyzer 40 can detect photoelectrons efficiently. That is, the posture of the stage 13a is changed by the posture control means 13b so that the sample surface 12a has a posture (direction) orthogonal to the direction connecting the measurement point 12b of the sample surface 12a and the electron energy analyzer 40. .

  After the desired data is obtained by the irradiation of ultraviolet rays, the ultraviolet ray source 32 is stopped or the irradiation of ultraviolet rays is stopped. Thereafter, the X-ray source 31 is operated to irradiate the sample 12 (measurement point 12b) with X-rays. The electron energy analyzer 40 detects and analyzes the photoelectrons emitted from the sample 12 by this X-ray irradiation. In this way, XPS spectrum data is obtained from the electron energy analyzer 40. In addition, after the ultraviolet irradiation, the stage 13a is preferably changed to an X-ray irradiation posture so that the electron energy analyzer 40 can efficiently detect photoelectrons emitted by the X-ray irradiation.

  After desired data is obtained by X-ray irradiation, the X-ray source 31 is stopped or X-ray irradiation is stopped. Then, the manipulator 13 is operated to change the posture of the stage 13a so that the sample surface 12a is horizontal. Thereafter, the low-angle electron beam source 33a or the vertical electron beam source 33b is operated to irradiate the sample 12 (measurement point 12b) with the electron beam, and the electron energy analyzer 40 detects the electrons scattered by the sample (scattered electrons). And analyze. In this way, the REELS and plasmon loss peak data at positions corresponding to the sample surface 12a and the incident depth are obtained from the electron energy analyzer 40.

  After desired data is obtained by electron beam irradiation from a low angle and electron beam irradiation from the vertical direction on the sample surface 12a, the low angle electron beam source 33a and the vertical electron beam source 33b are stopped, or The electron beam irradiation is stopped. In the present embodiment, ultraviolet rays, X-rays, and electron beams having different irradiation angles are sequentially irradiated and each spectrum is continuously measured. However, only individual spectra may be measured.

  Further, as described above, the ion gun 15 is used not only for removing contaminants and oxide films on the sample surface 12a to be measured but also for analyzing the sample 12 in the depth direction. That is, by operating the ion gun 15 and irradiating the sample surface 12a with the ion beam, a predetermined region of the sample surface 12a is uniformly etched at a constant depth. In this state, information such as the electronic structure of the sample 12 at the certain depth can be obtained by irradiating each excitation source 30 with an electromagnetic wave or an electron beam. Thereafter, by repeating the above procedure, information such as the electronic structure of the sample 12 in the depth direction can be obtained.

  In addition, when information such as the electronic structure on the surface of the sample 12 after the heat treatment (or cooling treatment) is necessary, after the sample 12 is placed on the stage 13a in the above procedure, the stage 13a The sample 12 is heated (or cooled) by the heating / cooling device 13c. Then, according to the said procedure, each excitation source 30 is irradiated and a measurement (analysis) is performed.

  Next, functions and effects of the analyzer 10 will be described.

  The analyzer 10 is arranged at one vacuum vessel 11, a stage 13 a for holding the sample 12 in the vacuum vessel 11, and a position in the vacuum vessel 11 facing the measurement point 12 b of the sample 12. The X-ray source 31 for irradiating 12b with X-rays, the ultraviolet ray source 32 for irradiating ultraviolet rays, and a plurality of electron beam sources 33, 33,... For irradiating electron beams, and the excitation sources 31, 32, 33. And an electron energy analyzer 40 for detecting photoelectrons emitted from the sample 12 or scattered electrons scattered by the sample 12. The plurality of electron beam sources 33, 33,... Are arranged such that the incident angles of the electron beams with respect to the sample surface 12a are different. Therefore, each measurement (analysis) by XPS, UPS, and REELS is performed in a state where the sample 12 is held on the stage 13a, and an increase in work time when the sample 12 is moved between analyzers as in the past, There is no measurement point shift in each measurement. Furthermore, since each measurement is performed in the same vacuum vessel 11, the sample 12 is not exposed to the atmosphere. Therefore, the sample 12 is not polluted by the atmosphere. Therefore, the data obtained by each measurement method can be comprehensively evaluated, and various highly accurate data (information) such as the electronic structure or local structure of the surface or interface of the sample 12, the electronic state, the work function, the band gap, etc. can get. In addition, since the obtained data (spectrum) is a result at the same measurement point 12b of the sample 12, the problem of separation of evaluation between spectra due to measurement point errors is also solved.

  Further, without moving the electron beam source 33, a plurality of electron beams 33, 33,... Can be sequentially irradiated at different incident angles with respect to the measurement point 12b on the sample surface 12a. Therefore, when obtaining the structural information of the sample 12 at the incident depth corresponding to the incident angle of the electron beam, it is not necessary to move the electron beam source 33 to a predetermined position. Furthermore, since it is not necessary to move the electron beam source 33 when the electron beam is incident again at the same incident angle, it is very easy to ensure the reproducibility of the incident angle.

  Moreover, since photoelectrons and scattered electrons can be detected by one electron energy analyzer 40, the apparatus 10 can be reduced in size and cost.

  In the present embodiment, the plurality of electron beam sources 33, 33,... Are a vertical electron beam source 33b that irradiates the sample surface 12a with an electron beam from the vertical direction, and a low angle electron that irradiates the electron beam from a low angle. They are two electron beam sources with the source 33a. The electron energy analyzer 40 is opposed to the low-angle electron beam source 33a with the sample 12 in between, and the detection angle is an angle corresponding to the incident angle of the electron beam from the low-angle electron beam source 33a with respect to the sample surface 12a. It is arranged at such a position. Therefore, information such as the electronic structure between the sample surface 12a and the inside of the sample can be obtained by the two electron beam sources 33 and 33. That is, information such as the electronic structure at a depth position that varies greatly from the sample surface 12a toward the inside can be obtained. As a result, the number of electron beam sources 33 can be reduced, and the structure of the analyzer 10 can be simplified and the cost can be reduced.

  In the case of the present embodiment, the low-angle electron beam source 33a is arranged at a position where the incident angle of the electron beam with respect to the sample surface 12a is 10 ° to 15 °. Therefore, scattered electrons suitable for obtaining information such as the electronic structure in several atomic layers of the sample surface 12a are efficiently emitted, and information such as the electronic structure of the sample surface 12a is easily obtained.

  By the way, when the sample surface 12a is irradiated with an electron beam from a low angle, the yield of inelastically scattered electrons by the electron beam is very small. Therefore, as described above, by detecting scattered electrons at a position near the orbit when the irradiated electron beam is regularly reflected at the measurement point 12b, that is, a low angle corresponding to the irradiation angle of the low-angle electron beam source 33a. By using this detection angle, the electron energy analyzer 40 can efficiently detect the scattered electrons.

  Moreover, in this embodiment, after irradiating with an ultraviolet-ray and X-ray in order, a low angle electron beam or a vertical electron beam is irradiated in order. Therefore, after the sample surface 12a is measured by ultraviolet rays, information such as the electronic structure at a position deeper than the ultraviolet rays is measured by X-rays. Thereafter, information such as an electronic structure is further measured with an electron beam having a larger interaction with the atom. By irradiating in this order, it is not necessary to consider the damage of the sample 12 due to the previously irradiated electromagnetic wave or electron beam. Therefore, more accurate and detailed information such as the electronic structure on the surface of the sample 12 can be obtained.

  Further, since both the low-angle and vertical electron beam sources 33a and 33b are composed of scanning electron guns, a predetermined region including the measurement point 12b on the sample surface 12a is scanned with an electron beam with a predetermined acceleration voltage. . At that time, loss of electron energy occurs in the scanned region due to atoms interacting with the energy of interest, bonding state, and the like. Then, the electron energy analyzer detects the measurement point where the loss of electron energy occurs due to atoms and bonding states in the region and the intensity change of the scattered electrons including the energy loss, and synchronizes scanning and yield. Thus, a distribution map for each chemical state in the region can be obtained.

  Further, a secondary electron detector 17 for detecting secondary electrons emitted from the sample 12 by an electron beam irradiated from the vertical electron beam source 33b is further provided at a position facing the measurement point 12b of the sample 12. Therefore, an image of the sample surface 12a at the measurement point 12b of the sample 12 can be obtained based on the secondary electrons detected by the secondary electron detector 17, and the state of the sample surface 12a can be obtained as visual information.

  Further, the spectrum corresponding to each excitation source 31, 32, 33 is obtained by spectrum measuring means based on photoelectrons or scattered electrons detected by the electron energy analyzer 40 by irradiating the sample 12 from each excitation source 31, 32, 33. Can be obtained. These spectra are affected by a correction function (device function) unique to the spectrum measuring means. Therefore, spectra obtained individually by irradiation of the sample 12 by the respective excitation sources 31, 32, and 33 can be combined to obtain one continuous spectrum. More specifically, one of the data obtained by the electron energy analyzer 40 by irradiation of the sample 12 by each excitation source 31, 32, 33 is used, and the energy having a known peak position in the displayed spectrum is used. Perform calibration. By applying the deviation width at that time to other data, it is possible to calibrate the energy of all the data used for combining with one spectrum. Furthermore, by correcting the energy value of each data so that each data overlaps on energy, it can output as one spectrum continuous on energy as shown in FIG. By this continuous spectrum, the energy difference (band cap) between the valence band and the conduction band, which could not be directly evaluated by the electron spectrum until now, is evaluated by a direct energy value.

  Further, the posture control means 13b of the manipulator 13 is configured to be able to change the posture of the stage 13a without changing the relative position between the measurement point 12b of the sample 12 held on the stage 13a and the vacuum vessel 11. The X-ray source 31 and the ultraviolet ray source 32 are arranged closer to the electron energy analyzer 40 in the direction connecting the electron energy analyzer 40 and the low-angle electron beam source 33a than the measurement point 12b of the sample 12. Therefore, even if the posture of the stage 13a is changed by the posture control means 13b so that the sample surface 12a has a posture orthogonal to the direction connecting the measurement point 12b of the sample surface 12a and the electron energy analyzer 40, X The radiation source 31 (or ultraviolet light source 32) can irradiate the measurement point 12b of the sample 12 with X-rays (or ultraviolet light). By changing the posture of the stage 13a in this way, photoelectrons emitted from the sample surface 12a are efficiently detected by the electron energy analyzer 40, and information such as the electronic structure of the sample surface 12a can be obtained in more detail.

  In addition, an ion gun 15 that irradiates an ion beam to perform sputter etching on the measurement point 12b of the sample 12 faces the measurement point 12b of the sample 12, and the electron energy analyzer 40 and the low-angle electron beam source 33a. It is further provided on the electron energy analyzer 40 side in the connecting direction. Therefore, even if the stage 13a changes its posture as described above when irradiated with X-rays or ultraviolet rays, sputter etching in the vicinity of the measurement point 12b of the sample 12 becomes possible, and the composition distribution in the depth direction of the sample 12 becomes possible. In addition, information such as the electronic structure in the depth direction can be obtained with high accuracy. Furthermore, even if the posture of the stage 13a is changed as described above, contaminants and oxide films on the sample surface 12a can be removed, so that the information can be obtained with higher accuracy and detail.

  Further, the stage 13a is provided with at least one of heating means or cooling means for heating or cooling the sample (in this embodiment, a heating / cooling device 13c is provided). Therefore, the sample 12 can be heated or cooled, and information such as the electronic structure on the surface of the sample 12 can be obtained before and after the heating or cooling process.

  Note that the electron spectroscopic analysis composite apparatus 10 of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

The schematic block diagram of the plane direction of the electronic-spectroscopy analysis composite apparatus which concerns on this embodiment is shown. AA sectional drawing of FIG. 1 is shown. The BB sectional view of Drawing 1 is shown. An example of the waveform of the spectrum obtained by the electron spectroscopic analysis composite apparatus according to the present embodiment is shown. An example of the waveform of the spectrum obtained with the analyzer by each conventional spectroscopy is shown.

Explanation of symbols

10 Combined electron spectroscopy analyzer (analyzer)
11 Vacuum container 12 Sample 12a Sample surface 12b Measurement point 13a Sample holder (stage)
31 X-ray source 32 Ultraviolet source 33 Electron beam source 40 Electron energy analyzer

Claims (12)

A vacuum vessel;
A sample holder for holding the sample in the vacuum vessel;
A plurality of X-ray sources for irradiating X-rays, UV sources for irradiating ultraviolet rays, and a plurality of electron beams for irradiating the measurement points of the sample held by the sample holder in the vacuum vessel. An electron beam source of
An electron energy analyzer for detecting photoelectrons emitted from the sample by being irradiated with the X-ray, ultraviolet ray or electron beam or electrons scattered by the sample, and
The plurality of electron beam sources are arranged so that incident angles of electron beams with respect to the surface of the sample are different from each other. The electron spectroscopic analysis composite device according to claim 1,
The plurality of electron beam sources includes two electron beam sources, a vertical electron beam source that irradiates the surface of the sample with an electron beam from a vertical direction and a low angle electron beam source that irradiates an electron beam from a low angle. Yes,
The electron energy analyzer faces the low-angle electron beam source across the sample, and a detection angle is an angle corresponding to an incident angle of the electron beam from the low-angle electron beam source with respect to the surface of the sample. An electronic spectroscopic analysis composite apparatus characterized by being arranged at such a position. The electron spectroscopic analysis composite apparatus according to claim 2,
The electron beam source is a scanning electron gun. The electron spectroscopic analysis composite apparatus according to claim 2 or 3,
The low-angle electron beam source is arranged so that an incident angle of an electron beam with respect to the surface of the sample is 10 ° to 15 °. In the electron spectroscopic analysis composite device according to any one of claims 2 to 4,
An electron spectroscopic analysis characterized by further comprising a secondary electron detector for detecting secondary electrons emitted from the sample by an electron beam irradiated from the vertical electron beam source at a position facing a measurement point of the sample. Compound device. The electron spectroscopic analysis composite apparatus according to any one of claims 1 to 5,
Each spectrum based on the photoelectrons or scattered electrons detected by the electron energy analyzer is combined in energy by irradiating the sample from each excitation source of the X-ray source, the ultraviolet ray source, and the electron beam source. Equipped with a spectral measurement means that can produce two consecutive spectra,
The spectrum measuring unit has a common correction function for obtaining each spectrum based on the detected photoelectrons or scattered electrons. The electron spectroscopic analysis composite apparatus according to any one of claims 1 to 6,
A posture control means for controlling the posture of the sample holder;
The posture control means is configured to change the posture of the sample holder without changing the relative position between the measurement point of the sample held in the sample holder and the vacuum vessel,
The X-ray source and the ultraviolet ray source are arranged on the electron energy analyzer side in a direction connecting the electron energy analyzer and the low-angle electron beam source with respect to the measurement point of the sample. Compound device. The electron spectroscopic analysis composite device according to claim 7,
Electron energy analysis in a direction in which an ion gun that irradiates an ion beam to perform sputter etching on the measurement point of the sample faces the measurement point of the sample and connects the electron energy analyzer and the low-angle electron beam source An electron spectroscopic analysis composite apparatus, further provided on the vessel side. The electron spectroscopic analysis composite apparatus according to any one of claims 1 to 8,
The electron spectroscopic analysis composite apparatus, wherein the sample holder is provided with at least one of a heating unit and a cooling unit for heating or cooling the sample. A sample is introduced into the vacuum vessel and arranged so that the measurement point of this sample is at a predetermined position in the vacuum vessel,
After individually irradiating the measurement point of the sample with X-rays and ultraviolet rays, the same measurement point is irradiated with an electron beam in order from a plurality of directions,
An electron spectroscopic analysis method, wherein photoelectrons emitted from the sample by the irradiated X-rays, ultraviolet rays, or electron beams or electrons scattered by the sample are detected by the same electron energy analyzer. The electron spectroscopic analysis method according to claim 10,
The electron beams irradiated from the plurality of directions are electron beams from two directions that are irradiated in order from either the vertical electron beam irradiated from the vertical direction or the low angle electron beam irradiated from a low angle on the surface of the sample. And
The sample is opposed to the irradiation position of the low-angle electron beam across the sample and at a position corresponding to the incident angle of the low-angle electron beam with respect to the surface of the sample by the electron energy analyzer. An electron spectroscopic analysis method characterized in that each of the electrons scattered by the light is detected. The electron spectroscopic analysis method according to claim 11,
An electron spectroscopic analysis method characterized by irradiating a low-angle electron beam or a vertical electron beam in order from either one after sequentially irradiating ultraviolet rays and X-rays.

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