JP2003344319A - Ion scattering analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion scattering analyzer which analyzes scattering ions due to irradiation with an ion beam, which is miniaturized, which realizes an analysis with high resolution and high sensitivity, and which easily can perform a double channeling measurement. <P>SOLUTION: The ion scattering analyzer A is provided with an ion-beam generation means X used to irradiate a sample with an accelerated ion beam 1, an ion extraction means used to extract only a specified ionic species from the accelerated ion beam 1, and a spectrum measuring means used to measure an energy spectrum of the scattering ions scattered from the sample 2 when the sample 2 arranged inside a vacuum chamber 3 is irradiated with the ion beam 1 from which only the specific ionic species is extracted. The ion extraction means and the spectrum measuring means are constituted so as to be provided with a common bending magnet W. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The sample surface is irradiated with accelerated ions of single energy such as hydrogen or helium,
The present invention relates to an ion scattering analyzer for identifying a component element of a sample or analyzing a composition in a depth direction by measuring an energy spectrum of scattered ions scattered on the surface of the sample.

[0002]

2. Description of the Related Art In the field of semiconductor development in recent years, it is inevitable that the equivalent thickness of a gate insulating film is extremely thin (1 nm or less) due to the miniaturization of elements due to integration or miniaturization, and the actual film thickness is As it becomes thinner, the adoption of high dielectrics containing heavy elements is beginning. Further, in a magnetoresistive thin film head for a high density magnetic disk, a GMR or TMR having an ultrathin multilayer film structure in which ultrathin films of 1 nm or less are stacked
The adoption of is starting. With these materials, the surface layer,
Specifically, since the characteristics of a single atomic layer to several atomic layers (for example, vacancy, impurity adsorption, or abnormal growth) vary greatly, the information about defects in the surface layer is not available in the development process or production control. This is very important information. As a method of analyzing information on defects in the surface layer of such an ultrathin film sample, "secondary ion mass spectrometry: SIMS", "Auger electron spectroscopy: AE"
The destructive analysis method based on the surface spattering of the sample surface such as “S” has a limited application, so that the sample surface can be analyzed nondestructively by the “Rutherford backscattering method: RBS
The law is drawing attention. However, the widely known RBS method detects the energy spectrum of scattered ions scattered from a sample by irradiation of an accelerated ion beam using a surface barrier type semiconductor detector, and based on the detected energy spectrum. The element composition distribution under the surface of the sample is analyzed. Therefore, the resolution in the depth direction is determined by the energy resolution of the semiconductor detector and remains at most several tens nm. for that reason,
With such an RBS method, it has been impossible to analyze defects in the surface layer of the ultrathin film sample as described above. Therefore, "high resolution Rutherford backscattering method: HRBS method" was realized by Kimura (Kyoto University) and others by improving the conventional RBS method to realize depth resolution that enables analysis of each atomic layer on the sample surface. , "Developopm
ent of a Compact High-Res
solution RBS System for mo
Nonaly Analysis "(Appl. P
hys. Lett. 64 (1994) 2232) as an ion scattering analyzer using the HRBS method. (Prior Art) Ion Scattering Analyzer B
As shown in FIG. 2, an ion beam generator X (corresponding to ion beam generating means), a Wien filter Y and a slit 7 (corresponding to ion extracting means), a quadrupole lens 1
1 and a vacuum container 3 in which a sample 2 to be analyzed is placed,
An electromagnet spectrometer Z (corresponding to spectrum measuring means) for measuring the energy spectrum of scattered ions scattered from the surface of the sample 2 is provided.
The ion beam generator X uses the gas (for example, helium gas) supplied from the cylinder 15 for the ion source 1.
The light ions generated by 2 are accelerated in the accelerating tube 13 to a constant energy by the high voltage supplied from the Cockcroft type high voltage circuit 14 and then irradiated. The Wien filter Y and the slit 7 extract only specific ion species (for example, helium monovalent ions) from the ion beam 1 accelerated and irradiated by the ion beam generator X. Here, the Wien filter Y produces a deflection action (proportional to the momentum of the ions) by the magnetic field generated by the magnetic pole 17, the coil 18, and the return yoke 19 with respect to the passing ions, and an electric field generated by the parallel electrode 20. The deflecting action (proportional to the energy of ions) is a filter configured to work in mutually opposite directions, and causes only a specific ion species (for example, helium monovalent ions) of the ion beam 1 to go straight and It has the property of bending the trajectory of ion species other than (for example, helium divalent ion, hydrogen atom ion, etc.). Due to the characteristics of the Wien filter Y described above, ion species other than the specific ion species used for analysis are provided downstream of the Wien filter Y in the ion beam incident direction, and are set so that only straight-ahead ions can pass through. Further, it cannot be passed through the slit 7 and is removed. The ion beam 1 in which only specific ion species are extracted in this manner is used as the slit 7
It is focused by the quadrupole lens 11 provided on the downstream side of the ion beam incident direction, and the surface of the sample 2 is irradiated with a predetermined beam spot. The ion beam 1 irradiated on the surface of the sample 2 is scattered on the surface of the sample 2,
A part of the scattered ions is incident on the electromagnet spectrometer Z. Here, the electromagnet spectrometer Z guides the scattered ions passing therethrough to the detection element 8 after deflecting the scattered ions according to the energy of the scattered ions by the magnetic field generated by the coil 4, the return yoke 5, and the magnetic pole 6. It is a thing. As a result, in the detection element 8, it is possible to analyze the energy spectrum of the scattered ions scattered from the surface of the sample 2 in detail based on the position where the scattered ions are detected (the amount of deflection by the magnetic field). Thus, the ion scattering analyzer B is
It enables atomic layer level analysis of the sample surface that could not be measured by the conventional ion scattering analyzer applying the RBS method, and is also applied to the analysis of defects in the surface layer of the material of the ultra-thin film described above. be able to.

[0003]

However, the electromagnet spectrometer Z used in the ion scattering analyzer B is large in size as compared with the surface barrier type semiconductor detector which has been conventionally used. Since the coil 4, which is a constituent element, generates heat, it is necessary to install the electromagnet spectrometer Z and the vacuum container 3 with a certain distance. As a result, the ion scattering analyzer B has the following problems. (Problem 1) Compared with an ordinary electron microscope and other analyzers (which can be suppressed to about 1.5 m at most), the ion scattering analyzer B cannot avoid an increase in size ( The total length is about 4m). (Problem 2) Here, the scattering phenomenon of the RBS method is described by the following elastic scattering process. When an incident ion with energy E and mass M ₁ collides with a component atom of mass M ₂ located at a depth τ near the surface of the sample to be analyzed and is scattered at an angle θ, the energy E of the ion immediately after the collision ₁ is expressed by the following equation. E ₁ = K (M ₁ , M ₂ , θ) · E Equation 1 where K in the above Equation 1 is Kinematic
It is called Factor (hereinafter referred to as K factor), and is a coefficient having the following relationship.

[Equation 1] From the above equation 2, if M ₁ , M ₂ and θ are constant, the ratio of E to E ₁ is always constant, so that from the energy E _{1 of} the ions emitted from the sample, the components in the sample that collide The atomic mass can be uniquely calculated. Furthermore, the incident ions are
If incident at θ ₁ with respect to the normal line of the surface of the sample 2, the sample 2 is moved by COS θ ₁ / τ until the collision,
A certain amount of energy is lost due to inelastic scattering with the constituent atoms in the sample 2. Due to the loss of these energies, the deeper the position of the colliding atom, the lower the energy E _{1 of the} scattered ion detected. This phenomenon is the basic principle of Rutherford backscattering analysis. By the way, in the above-mentioned principle of Rutherford backscattering, K that expresses so-called resolution performance, that is, how the mass or depth position of the sample surface element is reflected in the energy of scattered ions.
Let us consider the characteristics of the factor (Equation 2). Figure 5 shows K
Amount of change of the target element of the factor with respect to mass difference: (ΔK / K)
/ (ΔM ₂ / M ₂ ) (however, ΔM ₂ = 1 amu) with respect to various target elements (B, N, S ...)
This is a graph with °) as a parameter. As is clear from the figure, the scattering angle is rearmost (scattering angle = 18
The closer to 0 °, the greater the change in the K factor (higher sensitivity), and the higher the sensitivity of discrimination of the target element. Therefore, in order to discriminate the target element with high sensitivity, it is desirable to analyze the scattered ions scattered from the sample surface, which has the rearmost scattering angle. Next, FIG. 6 shows the amount of change in the K factor per 1 ° of angular width within the width of the scattering angle of the scattered ions captured by the detection system (solid angle formed by the detection system):
(ΔK / K) / Δθ (where Δθ = 1 °) is plotted as a graph with the scattering angle (0 to 180 °) as a parameter, and for scattered ions captured within the finite solid angle of the detection system, The width of the scattering angle represents the degree to which the element identification ability is impaired. As is clear from the figure,
The degree of loss of the element discriminating ability within the finite solid angle of the detection system is the smallest at the forefront (scattering angle = 0 °) or the rearmost (scattering angle = 180 °), and shows the maximum near 90 °. Therefore, when the scattering angle (θ) is around 90 °, in order to secure the analysis accuracy (to suppress the change of the K factor), the solid angle of the detection system must inevitably be reduced, The capture efficiency (detection sensitivity) of scattered ions is reduced. Due to such a constitution, in the configuration, the conventionally known ion scattering analyzer B (see FIG. 2) in which the scattering angle (θ) of scattered ions has to be close to 90 °,
It cannot be said that optimal analysis is performed in terms of resolution performance or sensitivity. (Problem 3) On the other hand, as an example of an important analysis method in the RBS method, there are crystallinity evaluation using double channeling measurement, highly accurate quantification of light elements, or interstitial position identification of ion-implanted elements. Here, the outline of the ion channeling phenomenon will be described with reference to FIGS. 3A to 3C and FIG. 4. When the ion beam 1 is incident on the crystal base sample 2 from a direction other than the crystal axis,
As shown in (a), more scattering is caused by the atoms under the surface, and the resulting energy spectrum becomes noisy as shown by A in FIG. 4, and the information on the surface layer of the sample 2 is accurately obtained. I can't figure it out. Therefore, if the crystal axis direction and the incident direction of the ion beam 1 are aligned by inclining the sample 2 appropriately, FIG.
As shown in FIG. 4, the surface lattice atoms hide the atoms under the surface of the skin, and the measured energy spectrum is B in FIG. That is, the sample surface peak becomes clear, and in the energy spectrum A, the signal of the light element hidden by the scattering from the atoms under the surface can be detected. like this,
The measurement under the condition that the crystal axis of the sample and the incident direction of the ion beam are aligned (channeling condition) is called ion channeling measurement and is effective in the above-mentioned crystallinity evaluation. Furthermore, of the above ion channeling measurements,
Regarding the direction of detecting scattered ions, the measurement under the condition (double channeling condition) as shown in FIG. 3 (c) aligned with the crystal axis of Sample 2 (in the figure, the diagonal direction of the lattice atoms of Sample 2) , Called double channeling measurement. According to this, since the deeper signal is further reduced as compared with the above-mentioned ion channeling measurement, more rigorous sample analysis becomes possible and it becomes possible to effectively detect scattered ions due to impurities existing between crystal lattices. It is also effective for identifying the interstitial position of ion-implanted impurities. (The measured energy spectrum is C in FIG. 4.) As described above, the use of the double channeling measurement in the analysis of the sample using the RBS method can be applied to more diverse analyzes and the analysis accuracy can be improved. Therefore, it is very important. Here, in order to satisfy the channeling condition in the double channeling measurement, it is necessary to align the ion beam incident direction with the crystal axis of the sample and the detection direction of scattered ions with high precision. However, in the above-mentioned conventional ion scattering analyzer B, it is difficult to install the electromagnet spectrometer Z for detecting scattered ions with high accuracy according to the crystal axis of the sample each time the measurement is performed. Channeling measurements were virtually impossible. Therefore,
The present invention has been made in view of the above circumstances, and an object thereof is an ion scattering analyzer for analyzing scattered ions due to irradiation of an ion beam, which has a high resolution and a high resolution as well as downsizing of the device. It is intended to realize a sensitive analysis and to provide an instrument that can easily perform double channeling measurement.

[0004]

In order to achieve the above object, the present invention provides an ion beam generating means for irradiating an accelerated ion beam, and an ion for extracting only a specific ion species from the accelerated ion beam. An extraction means and a spectrum measurement means for measuring an energy spectrum of scattered ions scattered from the sample when the sample placed in a vacuum container is irradiated with the ion beam in which only a specific ion species is extracted In the above ion scattering analyzer, the ion extracting means and the spectrum measuring means are configured to include a common bending electromagnet, and the ion scattering analyzer is configured. With such a configuration, it is possible to reduce the size of the conventional ion scattering analyzer, which is a major factor that hinders its spread, and to reduce the size. Further, in the ion scattering analyzer according to the present invention, only a single port connected to the sample chamber is used and the ion beam (1
Since it is possible to inject the secondary beam) and extract scattered ions, it is possible to connect to not only the sample chamber prepared for this analyzer but also a chamber that has at least one port that can be connected to this analyzer. The measurement can be performed under the conditions of. For example, the deposition chamber of the molecular beam epitaxial deposition system is shared as a sample chamber, and the composition change of the sample can be observed with this device while depositing a film, or it can be connected to a high temperature chamber equipped with a heater on the sample stage to increase the temperature. Can be analyzed. That is, in the film forming process and the surface processing process,
A device that can be used as a -situ (in-situ) observation device can be configured.

The spectrum measuring means measures the energy spectrum of the scattered ions scattered near the rearmost (scattering angle of 180 °) among the scattered ions scattered from the sample by the irradiation of the ion beam. It is desirable to be provided as follows. This allows RBS
It is possible to realize the highest resolution and high sensitivity of sample analysis using the method. Here, when performing measurement with the above-mentioned scattered ions scattered to the rear,
By aligning the incident direction of the ion beam with the crystal axis of the sample, the direction for detecting the scattered ions is also aligned with the crystal axis of the sample (double channeling condition is satisfied).
Therefore, it is possible to perform the double channeling measurement, which is not possible with the conventionally known ion scattering analyzer.

Furthermore, the deflection magnet has an incident angle at which the scattered ions scattered from the sample enter the deflecting electromagnet, and an outgoing angle at which the scattered ion incident on the deflecting electromagnet exits. It is also conceivable that the and can be adjusted arbitrarily. According to such a configuration, the deflected ions incident on the deflection magnet are generated so as to generate a predetermined magnetic field satisfying the double focusing condition capable of being focused at one point on the spectrum measuring means. It is possible to adjust the magnet. That is, even when the sample element to be measured is different and the double focusing condition is different, by adjusting the incident angle and the output angle of the scattered ions with respect to the deflection magnet according to the double focusing condition, Accurate energy analysis is always possible. Here, since the incident point of the scattered ions is also the outgoing point of the ion beam at the same time, changing the incident angle with respect to the deflection magnet depending on the sample (the scattered ions) means that the deflection magnet of the ion beam is simultaneously changed. It means that the emission angle with respect to is changed. Therefore, in the case of the above-described embodiment, it is desirable to provide one or more quadrupole electromagnetic lenses upstream of the deflection electromagnet in the ion beam incident direction. As a result, it becomes possible to electrically correct the focused and divergent state of the ion beam, and even when the exit angle of the ion beam in the deflection electromagnet is changed, the surface of the sample is formed by the ion beam forming a predetermined beam spot. Can be irradiated.

Further, it is conceivable that a mode further comprising neutral scattering particle spectrum measuring means for measuring the energy spectrum of the neutral scattering particles scattered from the sample together with the scattered ions by the irradiation of the ion beam. . In this case, it becomes possible to compensate the element quantitativeness of the sample by using the measured energy spectrum of the neutral scattering particles, which can further improve the analysis accuracy.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments and examples of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention. It should be noted that the following embodiments and examples are merely examples embodying the present invention and are not of the nature to limit the technical scope of the present invention. 1 is a diagram showing a schematic configuration of an ion scattering analyzer according to an embodiment of the present invention, FIG. 2 is a diagram showing a schematic configuration of a conventionally known ion scattering analyzer, and FIG. 3 is a physics of ion channeling phenomenon. Fig. 4 is a diagram showing the relationship between the angle of incidence of the ion beam and the RBS spectrum, Fig. 5 is a diagram showing the amount of change in the K factor with respect to the mass difference of the target element, and Fig. 6 is the solid angle formed by the detection system. 5 is a diagram showing the amount of change in the K factor per 1 ° of the angular width in FIG.

The ion scattering analyzer according to the embodiment of the present invention is embodied as an ion scattering analyzer A as shown in FIG. The ion scattering analyzer A includes an ion beam generator X (corresponding to an ion beam generating means), a quadrupole electromagnetic lens 10, and a deflection electromagnet W (a common deflection electromagnet provided in the ion extracting means and the spectrum measuring means). (Corresponding), the slit 7, the vacuum container 3 in which the sample 2 to be analyzed is placed, and the detection element 8 (corresponding to spectrum measuring means). The ion beam generator X is a gas supplied from the cylinder 15 (for example,
Light ions generated by the ion source 12 using helium gas) are accelerated in the accelerating tube 13 to a constant energy by the high voltage supplied from the Cockcroft high voltage circuit 14, and then irradiated. The quadrupole electromagnetic lens 10 is
The deflection electromagnet provided downstream of the ion beam incident direction of the quadrupole electromagnetic lens 10 so that the ion beam 1 irradiated from the ion beam generator X forms a predetermined spot shape on the surface of the sample 2. The lens condition is set in consideration of the deflection effect by the magnetic field generated by W, and the incident ion beam 1 is shaped into a vertical and horizontal oscillation state (emittance). The deflection electromagnet W introduces the ion beam 1 shaped in the vertical and horizontal oscillation states into the gap 6c (see the cross-sectional view shown in FIG. 1) sandwiched by the opposing magnetic poles 6. Here, in the deflection electromagnet W, only a specific ion species (helium monovalent ions in this embodiment) is deflected by 90 ° by a magnetic field generated by the magnetic pole 6, the coil 4, and the return yoke 5, and It is set so as to be emitted toward the vacuum container 3 provided downstream of the deflection electromagnet W in the ion beam incident direction. Therefore, ion species other than helium monovalent ions used for analysis can pass through the slit 7 which is provided on the upstream side of the vacuum vessel 3 in the ion beam incident direction and is set so that only straight-ahead ions can pass. Be removed without. The ion beam 1 in which only helium monovalent ions are extracted in this way
However, the helium monovalent ions introduced into the vacuum vessel 3 introduced into the vacuum vessel 3 are scattered on the sample 2 which is suitably tilted and arranged so as to satisfy the ion channeling condition described above. To be done. Of the helium monovalent ions scattered from the surface of the sample 2, the helium monovalent ions (hereinafter simply referred to as scattered helium) scattered in the ion beam incident direction of the vacuum container 3, that is, in the vicinity of the rearmost (scattering angle 180 °). The monovalent ions) pass through the slit 7 and are incident on the gap 6c of the magnetic pole 6 of the deflection electromagnet W again. In this case, the scattered helium monovalent ions incident on the deflecting electromagnet W are generated by the magnetic fields generated by the magnetic poles 6, the coils 4, and the return yoke 5 as in the case where the ion beam is incident. After being deflected in accordance with the above, the light is emitted toward the detection element 8 provided on the deflection electromagnet W. Here, the incident angle when the scattered helium monovalent ions are incident on the deflecting electromagnet W and the outgoing angle when the scattered helium monovalent ions are emitted from the deflecting electromagnet W are in accordance with the double focusing condition described later. With suitable settings, the scattered helium monovalent ions can be focused on the detection element 8 at one point. Thus, in the detection element 8, the energy spectrum of the scattered helium monovalent ions from the surface of the sample 2 is accurately determined based on the position (the amount of deflection by the magnetic field) at which the scattered helium monovalent ions focused on one point are detected. It becomes possible to analyze. As described above, the ion scattering analyzer A according to the present embodiment
Is the Wien filter Y and the electromagnet spectrometer Z in the conventionally known ion scattering analyzer B.
However, focusing on the fact that the deflection action by the deflection electromagnet is used together to realize the function, the feature is that the deflection electromagnet is shared. As a result, it is possible to make the device more compact than the conventionally known device. Further, in the ion scattering analyzer A according to the present embodiment, the detection element 8 can be provided at a position where the scattered ions from the surface of the sample 2 scattered near the rearmost position are measured. Therefore, the theoretically most accurate and highly sensitive analysis can be performed. Here, when the scattered ions scattered near the rearmost are used for analysis,
As shown in (d), if the ion beams incident on the crystal axis of the sample 2 are aligned, the detection direction of scattered ions and the crystal axis of the sample 2 are necessarily aligned. Therefore, the ion scattering analyzer A according to the present embodiment is
The conventionally known ion scattering analyzer B can easily realize double channeling measurement, which is virtually impossible, by appropriately adjusting the inclination of the sample 2.

Next, the setting of the incident angle when helium monovalent ions are incident on the deflection electromagnet W and the emission angle when helium monovalent ions are emitted from the deflection electromagnet W will be described. Here, the incident angle when the helium monovalent ions are incident and the outgoing angle when the helium monovalent ions are emitted are the helium monovalent ions scattered from the sample on the detection element 8.
It is necessary to set it according to the condition (double focusing condition) to focus again. Here, such a condition is
Similar to the case of the above-mentioned electromagnet spectrometer Z used in a conventionally known ion scattering analyzer, it can be easily calculated by numerical analysis of charged particle trajectories in a magnetic field. For example, the distance from the sample 2 to the deflection electromagnet W and the distance from the deflection electromagnet W to the detection element 8 are both 1
When the helium monovalent ions are deflected by 120 ° with an orbital radius of 150 R by a magnetic field in the deflection electromagnet W of 74 mm, the incident angle and the exit angle of the deflection electromagnet W are respectively helium monovalent ions. By inclining at an angle of 41 ° with respect to the normal line of the central orbit of, the double focusing condition is satisfied, and helium monovalent ions can be focused on one point on the detection element 8. However, when the sample 2 to be analyzed is different, the energies of scattered ions are also different, and thus the double focusing condition may be different.
For example, when the energy of scattered scattered ions is small, as shown by an arrow 1a in FIG.
However, when the energy of scattered scattered ions is small and large, the deflection by the deflection electromagnet W becomes small as indicated by an arrow 1b in the figure.
As described above, in order to adapt to the double focusing condition which differs depending on the sample 2 to be analyzed, in the present embodiment, the movable magnetic pole 6a near the position where the scattered ions are incident and the position where the scattered ions are emitted. The movable magnetic pole 6b in the vicinity is formed in a mechanically slidable semi-cylindrical shape, and has a mechanism for rotating it as needed by a rotation mechanism (not shown).
With such a configuration, the movable magnetic poles 6 can be arranged in accordance with the double focusing condition calculated for each type of sample.
By sliding a and 6b, the angle (shape) of the magnetic pole boundary surface of the deflection electromagnet W can be arbitrarily set, and even when the double focusing conditions are different, the scattered ions are always It is possible to generate a magnetic field that focuses the light on the detection element 8 at one point. here,
Since the movable magnetic pole 6a is both the incident point of scattered ions and the emission point of the ion beam emitted from the ion beam generator X, the movable magnetic pole 6a is rotated according to the double focusing condition. In this case, it should be noted that the angle of emission of the ion beam emitted from the deflection electromagnet W is changed. That is, the focused / divergent state of the ion beam may change due to the change of the emission angle, and the beam spot (for example, 0.1 mmφ or less) formed by the ion beam on the surface of the sample 2 may change. Therefore, in the present embodiment, two quadrupole electromagnetic lenses 10 are provided upstream of the deflection electromagnet W in the ion beam incident direction. As a result, the deviation of the focused and divergent state of the ion beam caused by the rotation of the movable magnetic pole 6a is
It becomes possible to make electrical correction by means of the quadrupole electromagnetic lens 10, and even if the emission angle (focusing / divergence state) of the ion beam is changed according to the change of the double focusing condition, a predetermined beam spot is obtained. It becomes possible to irradiate the surface of the sample with the ion beam that forms the.

Here, when the sample 2 is irradiated with the ion beam, not all of them are backscattered as scattered ions, and the neutral scattering particles are deprived of the charge of the sample 2 or received. There is something that becomes. The energy spectrum of the neutral scattering particles can be important information for knowing the internal composition of the sample 2. Therefore, in the ion scattering analyzer A according to the present embodiment, as shown in FIG. 1, the neutral scattering particle detecting means 9 for detecting the neutral scattering particles is coaxial with the incident axis of the scattering ions to the deflection electromagnet W. Is provided. By using a superconducting tunnel junction type detector having an energy gap of several meV as the neutral scattering particle detecting means 9, low energy neutral scattering particles can also be detected. As a result, it becomes possible to accurately detect the neutral scattered particles that are generated at the same time as the scattered ions by the irradiation of the ion beam, and for example, it can be used for compensating the element quantitativeness of the sample 2 described above. As a result, the accuracy of analysis can be improved. Here, it is desirable that the neutral scattering particle detecting means 9 is provided with an ion beam shielding plate 9a for preventing the incident ion beam from being mixed, as shown in the figure.

[0012]

As described above, according to the present invention, an ion beam generating means for irradiating an accelerated ion beam,
Ion extraction means for extracting only specific ion species from the accelerated ion beam, and scattering from the sample when the sample placed in the vacuum container is irradiated with the ion beam extracted only for specific ion species In the ion scattering analyzer including a spectrum measuring means for measuring the energy spectrum of the scattered ions, the ion extracting means and the spectrum measuring means are provided with a common bending electromagnet. Configured as a scattering analyzer. With such a configuration, it is possible to reduce the size of the conventional ion scattering analyzer, which is a major factor that hinders its spread, and to reduce the size. Further, in the ion scattering analyzer according to the present invention, it is possible to inject an ion beam (primary beam) and extract scattered ions using only a single port connected to the sample chamber. Not only the sample chamber prepared for the analyzer but also a chamber having at least one port connectable to the analyzer can be connected to perform measurement under various conditions.
For example, the deposition chamber of the molecular beam epitaxial deposition system is shared as a sample chamber, and the composition change of the sample can be observed with this device while depositing a film, or it can be connected to a high temperature chamber equipped with a heater on the sample stage to increase the temperature. Can be analyzed. That is,
It is possible to configure an apparatus that can be used as an in-situ (in-situ) observation apparatus in the film forming process and the surface processing process.

The spectrum measuring means measures the energy spectrum of the scattered ions scattered near the rearmost (scattering angle of 180 °) among the scattered ions scattered from the sample by the irradiation of the ion beam. It is desirable to be provided as follows. This allows RBS
It is possible to realize the highest resolution and high sensitivity of sample analysis using the method. Here, when performing measurement with the above-mentioned scattered ions scattered to the rear,
By aligning the incident direction of the ion beam with the crystal axis of the sample, the direction for detecting the scattered ions is also aligned with the crystal axis of the sample (double channeling condition is satisfied).
Therefore, it is possible to perform the double channeling measurement, which is not possible with the conventionally known ion scattering analyzer.

Further, the deflection magnet has an incident angle when the scattered ions scattered from the sample are incident on the deflection electromagnet, and an emission angle when the scattered ions incident on the deflection electromagnet are emitted. It is also conceivable that the and can be adjusted arbitrarily. According to such a configuration, the scattered ions that are incident on the deflection magnet are generated so as to generate a predetermined magnetic field that satisfies the double focusing condition that allows the scattered ions to be focused at one point on the spectrum measuring means. It is possible to adjust the magnet. That is, even when the sample element to be measured is different and the double focusing condition is different, by adjusting the incident angle and the output angle of the scattered ions with respect to the deflection magnet according to the double focusing condition, Accurate energy analysis is always possible. Here, since the incident point of the scattered ions is also the outgoing point of the ion beam at the same time, changing the incident angle with respect to the deflection magnet depending on the sample (the scattered ions) means that the deflection magnet of the ion beam is simultaneously changed. It means that the emission angle with respect to is changed. Therefore, in the case of the above-described embodiment, it is desirable to provide one or more quadrupole electromagnetic lenses upstream of the deflection electromagnet in the ion beam incident direction. As a result, it becomes possible to electrically correct the focused and divergent state of the ion beam, and even when the exit angle of the ion beam in the deflection electromagnet is changed, the surface of the sample is formed by the ion beam forming a predetermined beam spot. Can be irradiated.

Further, a mode may be considered, which further comprises neutral scattering particle spectrum measuring means for measuring the energy spectrum of the neutral scattering particles scattered from the sample together with the scattered ions by the irradiation of the ion beam. . In this case, it becomes possible to compensate the element quantitativeness of the sample by using the measured energy spectrum of the neutral scattering particles, which can further improve the analysis accuracy.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an ion scattering analyzer according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a conventionally known ion scattering analyzer.

FIG. 3 is a physical explanatory diagram of the ion channeling phenomenon.

FIG. 4 is a diagram showing a relationship between an incident angle of an ion beam and an RBS spectrum.

FIG. 5 is a diagram showing the amount of change in the K factor with respect to the mass difference of the target element.

FIG. 6 is a diagram showing the amount of change in the K factor per 1 ° of angular width in the solid angle formed by the detection system.

[Explanation of symbols]

A ... Ion scattering analyzer B ... Ion scattering analyzer W ... Analytical electromagnet X ... Ion beam generator Y ... Vienna filter Z ... Electromagnetic spectrometer 1 ... Ion beam 2… Sample 3 ... Vacuum container 4 ... coil 5 ... Return yoke 6 ... Magnetic pole 6a ... movable magnetic pole 6b ... movable magnetic pole 6c ... Gap 7 ... Slit 8 ... Detection element 9. Neutral scattering particle detecting means 9a ... Ion beam shield plate 10 ... Quadrupole electromagnetic lens 11 ... Quadrupole lens 12 ... Ion source 13 ... Accelerator 14 ... Cockcroft type high voltage circuit 15 ... Cylinder 16 ... Insulating gas filling tank 17 ... Magnetic pole 18 ... Coil 19 ... Return yoke 20 ... Parallel electrodes

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ichihara             1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture             Kobe Steel Co., Ltd.Kobe Research Institute (72) Inventor Hirofumi Fukuyama             2-3-3 Niihama, Arai-cho, Takasago, Hyogo Prefecture             Takasago Works, Kobe Steel, Ltd. F-term (reference) 2G001 AA05 BA06 BA15 CA04 EA04                       GA01 GA06 GA08 GA13 KA01                       SA01 SA04

Claims (5)

[Claims] 1. An ion beam generating means for irradiating an accelerated ion beam, an ion extracting means for extracting only a specific ion species from the accelerated ion beam, and the ion beam for extracting only a specific ion species. And a spectrum measuring means for measuring an energy spectrum of scattered ions scattered from the sample when the sample is placed in a vacuum container. However, the ion scattering analyzer is characterized by comprising a common bending electromagnet. 2. The spectrum measuring means measures an energy spectrum of the scattered ions scattered near the rearmost (scattering angle 180 °) among the scattered ions scattered from the sample by the irradiation of the ion beam. The ion scattering analyzer according to claim 1, wherein the ion scattering analyzer is provided as follows. 3. An angle of incidence of the deflecting magnet when the scattered ions scattered from the sample enter the deflecting electromagnet, and an angle of emission of the scattering ion incident on the deflecting electromagnet. 3. The ion scattering analyzer according to claim 1 or 2, which can be arbitrarily adjusted. 4. The ion scattering analyzer according to claim 3, wherein one or more quadrupole electromagnetic lenses are provided upstream of the deflection electromagnet in the ion beam incident direction. 5. The neutral scattering particle spectrum measuring means for measuring the energy spectrum of neutral scattering particles scattered from the sample together with the scattered ions by irradiation of the ion beam, according to claim 1. The ion scattering analyzer according to any one of claims.