JPH0921769A - Ion beam analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ion beam analyzer capable of easily and surely realizing the selection of a beam size (shape) at a low cost corresponding to analyzing technique. SOLUTION: The ion beam analyzer comprises an angle varying means 15 capable of holding a sample 13 on a sample pedestal 12 so that the surface to be irradiated becomes perpendicular or oblique to an ion beam 7, a first slit 9A having a circular or square opening used also as RBS (backscattering analysis) or PIXE(proton-induced x-ray emission), a second slit iB having a rectangular opening of a short side in a beam scattering direction for special purpose of ERDA(elastic recoil particle detection method), and a slit holding means for alternately installing both the slits on an ion beam line, wherein both the slits are formed integrally on one plate piece, the holding means is so coupled to the piece as to be able to alternately dispose the opening on the beam line, the means 15 is provided in interlocking relation with the holding means, and the surface to be irradiated is set to be perpendicular or oblique in response to the disposition of the first and second slits on the beam line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects ion beam scattering energy generated when a sample is irradiated with a high energy ion beam, and analyzes light elements on the surface of the sample, and analyzes light element distribution in the depth direction. The present invention relates to an ion beam analyzer capable of performing the above.

[0002]

2. Description of the Related Art Conventionally, an elastic recoil particle detection method (ER) has been used as one analysis method in high energy ion beam analysis.
DA: Elastic Recoiling Detection Analysis), which is used as an analysis of light elements. This method
A method of ejecting light elements on the surface of a sample in a chamber by a high-energy ion beam that is focused by an electromagnet lens or cut out through a slit and irradiated.For example, in the latter method, the sample is ionized. A method of obliquely injecting a high-energy ion beam at an angle with respect to the incident direction of the beam and ejecting the light element forward, measuring the energy spectrum of the ejected light element, and then The count value of the recoil particles with respect to the incident ion beam amount of is the amount of the light element.

In this analysis, since the collision between the incident ions and the recoil particles is elastic scattering, it is possible to calculate the concentration using physical data. The theoretical formula in this case is: Y = Q · Ω · σ · N · Δx / sinα (A) where Y: spectrum height (count number) at depth x, Q: ion dose, Ω: Detector solid angle, σ: Scattering cross section, N: Hydrogen concentration, Δx: Thickness of sample at depth x, 1 / sin α: Oblique incident correction value, where ions are incident and scattered It is known that each angle (incident angle α, emission angle β) that pops out by doing so theoretically affects the quantification accuracy of the amount of the light element. Therefore, the semiconductor detector, which is a detector for detecting recoil particles, is provided with a slit because it is necessary to guide ion beam scattering from the correct direction to the detector. This slit has a narrow width in the direction in which the beam is scattered so that the recoil angle θ (α + β) can be set correctly, and the width in the direction perpendicular to that is to increase the beam yield (the amount of ions jumping into the detector). It is wide.

From the above formula (A), the deviation of the recoil angle θ of the ions affects the value of Y based on the term of sin α, and
The energy E of the recoiled particle is finally calculated by the following equation (B)
, E _out = K _r E ₁ − [(K _r S _in / sin α) + (S _out / sin β)] x (B), the amount of hydrogen at the depth x is determined by the energy spectrum. The recoil angle θ (α, β) is also included in this equation (B), and this angle determines the analysis accuracy. Therefore, it is extremely important to suppress this recoil angle θ so that it falls within a certain range from the set value, because it improves the accuracy of the analyzer, but for that reason, there is a limit to narrowing the slit width. Therefore, the sample and the slit are separated by a large distance.

Further, in addition to installing the sample and the slit at a large distance from each other, it has been conventionally practiced to reduce the spot diameter of the beam hitting the sample to improve the accuracy of the beam scattering angle. There is. As a concrete means for this, the beam from the slit is cut out and applied to the sample. There are two ways to narrow the beam by the electromagnetic field to make it smaller on the sample.

[0006]

In the above case, the slits are formed in a rectangular shape. However, if the sample is installed at an angle with respect to the incident direction of the ion beam. , A square-shaped ion beam is formed on the sample, and this is another usual analysis method, for example, Rutherford Backscattering Analysis (RBS).
ttering Spectro-scopy) and particle excitation X-ray analysis (PI
In XE (Particle Induced Xray Emission), there is a problem that the beam cutting slit shape is inconvenient for measurement.
On the other hand, in the case of 1, the various devices required for beam focusing are arranged on the beam line, which causes the disadvantages of increasing the size of the device and increasing the cost.

From the above, in various analysis methods using a high-energy ion beam, if each beam is made to be about 1 mm or less on the sample so that the same beam can be processed, In the irradiation of the sample, it is necessary to take measures suitable for each analysis.

The present invention has been made in order to solve such problems, and an object of the present invention is to analyze each analysis method in an ion beam analyzer having a single high energy ion beam line. It is an object of the present invention to provide an apparatus that can easily select a beam size (shape) corresponding to, and can be realized reliably and at low cost.

[0009]

The present invention has the following configuration to achieve the above object. That is, the present invention, in an ion beam analyzer for irradiating a sample with a high-energy ion beam passing through a slit installed on an ion beam line to perform elemental analysis or the like of the sample surface, on a sample table that holds the sample, There is provided an angle varying means capable of holding the sample such that the surface to be irradiated is a surface vertical to the ion beam or an inclined surface which is inclined in one direction, and the slit has a circular shape for both RBS and PIXE. A first slit with a shape or square opening, and E
A second slit having a rectangular opening having a short side in the beam scattering direction dedicated to RDA is provided, and further, slit holding means capable of alternately installing both slits on the ion beam line is provided. Ion beam analyzer.

According to the present invention, in the ion beam analyzer having the above-mentioned structure, the first slit and the second slit are integrally formed as one plate piece, while the slit holding means is provided on the plate piece. The ion beam analyzer is characterized in that it is provided so as to be connected to the plate piece so that round or square openings and rectangular openings can be alternately arranged on the ion beam line.

According to the present invention, in the ion beam analyzer having the above-mentioned structure, the first slit and the second slit are provided adjacent to each other before and after the ion beam line, respectively, while the slit holding means is provided for both slits. The ion beam analyzer is characterized in that the slits are connected to both slits so that they can be alternately arranged on the beam line.

According to the present invention, in the ion beam analyzer having the above-mentioned structure, the angle varying means provided on the sample stage is provided in an interlocking relationship with the slit holding means, and the first slit is on the ion beam line. In the ion beam analyzer, the irradiated surface is a vertical surface according to the arrangement of the second slit and the irradiated surface is an inclined surface according to the arrangement of the second slit on the ion beam line. is there.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, referring to FIG. 1, a sample stage 12 is provided with an angle varying means 15, and a surface to be irradiated is a surface vertical to an ion beam 7 or one direction. The sample can be held so as to have an inclined surface that is inclined obliquely. Further, the first slit 9A having a round or square opening for both RBS and PIXE, and the second slit 9B having a rectangular opening having a short side in the beam scattering direction for ERDA are provided, and both slits 9A are provided. , 9B
Is provided on the ion beam line alternately with a slit holding means 14.

ERDA in which the irradiation angle of the sample and the beam scattering direction are geometrically different from those of other analytical methods.
When performing the analysis by the method, the second slit 9B is arranged on the ion beam line by the operation of the slit holding means 14, and the sample stage 12 is moved by the angle changing means 15.
When the analysis by the RBS or PIXE method is performed, the first slit 9A is operated by the operation of the slit holding means 14 so that the irradiation surface is inclined so that the irradiation surface becomes an inclined surface. It may be arranged on the beam line, and the sample table 12 may be placed at the irradiation position by the operation of the angle varying means 15 so that the irradiation surface becomes a vertical surface. Thus, it is possible to perform analysis operations by different methods on the same sample stage and the same ion beam line, and to provide a multi-functional device that is easy to handle by simply operating the slit holding means 14 and the angle varying means 15. it can.

In this case, while the first slit 9A and the second slit 9B are integrally formed as one plate piece,
An operation for analysis is performed by providing the slit holding means 14 connected to the plate piece and the angle changing means 15 provided on the sample table 12 in an interlocking relationship with the slit holding means 14. Becomes even simpler.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows the outline of the structure of the ion beam analyzer according to the first embodiment of the present invention, and FIG. 2 shows the slit portion in the embodiment of FIG. 1 in an enlarged cross section. With reference to FIGS. 1 and 2, this ion beam analyzer includes an accelerator 1, an ion source 2, an accelerating tube 3, a deflection analyzing electromagnet 4, a primary slit 8, a first slit 9A, a second slit 9B, and a sample chamber 5. For provision, they are arranged in the order listed from front to rear. In this device, the accelerator 1, the ion source 2 and the accelerating tube 3 form an accelerator, while the deflection analyzing electromagnet 4 has a deflection coil 10a.
Further, a detector 11 and a sample table 12 are housed in the sample chamber 5. The accelerator and the entrance side of the deflection analysis electromagnet 4 are connected by a vacuum duct 6A for guiding the ion beam 7, and the exit side of the deflection analysis electromagnet 4 and the entrance side of the sample chamber 5 are the same. Is connected by a vacuum duct 6B for guiding the latter, and in the middle of the vacuum duct 6B provided with the axis of the latter extending horizontally, a rear-stage slit including a front-stage slit 8, a first slit 9A, and a second slit 9B from the upper side. 9 are provided.

In the ion beam analyzer having such a structure, the ion source 2 and the accelerator 1 generate ions and the accelerating tube 3 accelerates the ion beam 7, and the accelerated ion beam 7 passes through the deflection analyzing electromagnet 4. Usually, it is shaken at an angle of 15 ° or more, and the ion species are selected by energy selection during this period, and then the beam is cut out by the front slit 8 while moving straight in the vacuum duct 6B in the horizontal direction, and then the latter stage. The beam is further cut out by either one of the first slit 9A and the second slit 9B in the slit 9, and after the beam has a predetermined beam shape, it enters the sample chamber 5 and is held and fixed on the surface portion of the sample table 12. The sample 13 as a target is irradiated with the beam to connect the beam spots.

The first slit 9A and the second slit 9B are
A slit plate (referred to as an aperture) made of molybdenum (Mo) or tungsten (W) and having a predetermined shape is provided on the upper side for defining the beam size that directly impinges on the sample 13. The first slits 9A are formed in the respective slits by being perforated at a central position closer to them, and the first slits 9A have a circular frame (a) in FIG.
As shown therein, the opening is a circular round opening 19A.
The second slit 9B has a rectangular opening 19 having a horizontally long rectangular shape, as shown in the circular frame (b).
B. Needless to say, the opening of the first slit 9A may be a square opening having the same length and width in place of the round opening. And both slits 9A and 9B are
It is inserted in the vacuum duct 6B and positioned at a predetermined position in the front-rear direction, and is provided so as to cross the line of the ion beam 7 so that the plate surfaces are orthogonal to each other.

The first slit 9A and the second slit 9B, which are inserted in the vacuum duct 6B, are provided with slit holding means 14 which is provided by hermetically penetrating the peripheral wall of the vacuum duct 6B.
And is held at the predetermined location,
By operating the holding means 14 outside the vacuum duct 6B, the first slits 9A and the second slits 9B can be alternately arranged on the ion beam line. When 9A intervenes, the ion beam 7 passes through the round opening 19A, and conversely, when the second slit 9B intervenes, the ion beam 7 passes through the rectangular opening 19B.
The first slit 9A is used in the case of the RBS method or the PIXE method, and the second slit 9B is used in the case of the ERDA method, and is placed on the sample 13 held on the surface of the sample table 12. The beam is cut out in a predetermined size.

The slit holding means 14 includes a first slit holding means 14A directly connected to the first slit 9A,
The second slit holding means 14B is directly connected to the second slit 9B. Both holding means 14A, 14B have the same structure, and a rod 18 coaxially directly connected to each slit 9A, 9B and an air cylinder 16 mounted on the peripheral wall of the vacuum duct 6B and operated outside the duct.
And a bellows 17 for interposing the rod 18 and the air cylinder 16 to connect them to each other, and by extending the piston rod of the air cylinder 16, each slit 9A, 9B is interposed on the ion beam line. , Each slit 9 by shortening the piston rod
It is possible to retract A and 9B laterally from the ion beam line. Both holding means 14A and 14B are
When one is operating on the piston rod extension side,
The other is alternately operated in the forward and reverse directions so that the other operates on the piston rod shortening side.

The sample table 12 housed in the sample chamber 5 is held by the angle varying means 15 and attached to the chamber wall. Although the detailed structure of the angle varying means 15 is not shown, the angle varying means 15 is attached to the central portion on the back surface side of the sample table 12, and is held horizontally parallel to the plate surfaces of the slits 9A and 9B to support the bearing. The rotary switch 22 is provided with a rotary drive source such as a step motor for rotating the rotary shaft 22 about its own axis, and a limit switch 20. The angle varying means 15 is configured to rotate the rotary shaft 2 by the rotary drive source.
The sample table 12 is rotated by rotating 2 so that its surface, that is, the surface to be irradiated is in a state of a vertical surface orthogonal to the ion beam 7, or in one direction shown in FIG. It can be held in a state of an inclined surface that is inclined at a predetermined angle. In this case, the above-mentioned state of the vertical surface is accurately positioned as the origin, for example, by a mechanical stopper mechanism, while the state of the inclined surface inclined by a predetermined angle is:
It can be electrically detected by the limit switch 20, and this detection signal is introduced into the controller 21.

A method for evaluating the surface condition of the sample 3, for example, using the first embodiment described above will be described below.
In the case of the PIXE method, the angle varying means 15 is set to the origin state, and the sample table 12 holding the sample 3 on the surface portion is a vertical surface whose irradiation surface is orthogonal to the ion beam 7. Position it so that In this state, the first slit holding means 14A is instructed by the controller 21 based on the OFF signal of the limit switch 20.
Is the piston rod extension side, the second slit holding means 14
By operating B on the piston rod shortening side, the first slit 9A having the round opening 19A is inserted at a right angle on the ion beam line, and the second slit 9B having the rectangular opening 19B is inserted from the ion beam line. Evacuated. As a result, the ion beam 7 has a round opening 19
A circular beam spot corresponding to this, which is cut out by A, is irradiated on the surface of the sample 13 held in a vertical state, and thus analysis such as crystallinity evaluation can be performed.

On the other hand, in order to evaluate the surface condition by the ERDA method, the angle varying means 15 is operated in an inclined state,
The sample table 12 holding the sample 3 on its surface is positioned so that the surface to be irradiated is inclined in one direction perpendicular to the ion beam 7. In this state, based on the limit switch 20 outputting an ON signal, the second slit holding means 14B is set to the piston rod extension side and the first slit holding means 14A is set to the piston rod shortening side in response to a command from the controller 21, respectively. By operating, the second slit 9B having the rectangular opening 19B
Is inserted on the ion beam line at a right angle, and the circular aperture 1
The first slit 9A having 9A is retracted from the ion beam line. As a result, the ion beam 7 is cut out by the rectangular aperture 19B, and a rectangular beam spot having a short side in the beam scattering direction corresponding to the ion beam 7 is obliquely applied to the surface of the sample 13 held in an inclined state. Thus, analysis such as crystallinity evaluation by counting recoil particles can be performed.

FIG. 3 shows an outline of the structure of an ion beam analyzer according to the second embodiment of the present invention, and FIG. 4 shows an enlarged cross section of the front surface of the slit portion in the embodiment of FIG. Further, in FIG. 5, the right side surface of the slit portion is also shown in an enlarged manner. The second embodiment shown in FIGS. 3 to 5 is similar to the first embodiment, and corresponding members are designated by the same reference numerals.

The point of interest in this second embodiment is that
The first slit 9A and the second slit 9B are integrally provided by consolidating into one aperture, while the first slit holding means 14A and the second slit holding means 14B.
And are grouped as the slit holding means 14 having a single structure and provided so as to be connected to the aperture. That is, the circular opening 19A and the rectangular opening 19B are opened side by side in a vertical relationship with respect to one aperture, while the slit holding means 14 of a single structure composed of the rod 18, the air cylinder 16 and the bellows 17 is provided. The rod 18 has a structure directly connected to the aperture. By setting the expansion / contraction stroke of the slit holding means 14 to an appropriate value, it is possible to select and interpose the round openings 19A and the rectangular openings 19B alternately on the line of the ion beam 7. In the second embodiment configured as described above, the means for selectively switching in the case of the RBS, PIXE method or the ERDA method according to the purpose of analysis is equivalent to that in the first embodiment. Therefore, the description is omitted here.

[0026]

As described above, according to the present invention, the sample holder for holding the sample is arranged such that the surface to be irradiated is a surface vertical to the ion beam or an inclined surface inclined in one direction. Is provided with an angle varying means capable of holding the RBS and PIXE, and a first slit having a round or square opening for both RBS and PIXE and a rectangular opening having a short side in the beam scattering direction dedicated to ERDA. RBS, PIXE, ERDA are provided with two slits, and further provided with slit holding means capable of alternately installing both slits on the ion beam line.
The analysis method using high-energy ions can be set easily and inexpensively with one beam line. Further, in the case of the ERDA method, since the beam recoil angle based on the rectangular slit can be set easily and accurately, an ion beam analyzer capable of improving the ERDA analysis accuracy can be provided.

Further, according to the present invention, the first slit and the second slit are integrally formed as one plate piece,
The slit holding means is connected to the plate piece so that the round or square openings and the rectangular openings provided in the plate piece are alternately arranged on the ion beam line. It is possible to easily obtain two kinds of beam sizes by using the slit mechanism, and it is possible to obtain a beam with excellent economy and operability. Further, the angle varying means provided on the sample stage is provided in an interlocking relationship with the slit holding means, and the irradiated surface is a vertical surface according to the arrangement of the first slit on the ion beam line,
By arranging the irradiated surface to be an inclined surface according to the slits being arranged on the ion beam line, it is possible to select an appropriate slit according to its use for various analysis methods. A remarkable effect is achieved in labor saving in operation and prevention of erroneous operation.

[Brief description of drawings]

FIG. 1 is a schematic structural diagram of an ion beam analyzer according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a slit portion in the first embodiment shown in FIG.

FIG. 3 is a schematic structural diagram of an ion beam analyzer according to a second embodiment of the present invention.

4 is an enlarged sectional front view of a slit portion in the second embodiment shown in FIG.

FIG. 5 is a right side view corresponding to FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Accelerator 2 ... Ion source 3 ... Acceleration tube 4 ... Deflection analysis electromagnet 5 ... Sample chamber 6A ... Vacuum duct 6B ... Vacuum duct 7 ... Ion beam 8 ... Primary slit 9 ... Slit 9A ... 1st slit 9B ... 2nd slit 10 Deflection coil 11 Detector 12 Sample stage 13 Sample 14 Slit holding means 14A First slit holding means 14B Second slit holding means 15 Angle changing means 16 Air cylinder 17 Bellow 18 Rod 19A ... Round opening 19B ... Rectangular opening 20 ... Limit switch 21 ... Controller

Claims (4)

[Claims] 1. An ion beam analyzer for irradiating a sample with a high-energy ion beam passing through a slit installed on an ion beam line to perform elemental analysis or the like on the surface of the sample. An angle changing means capable of holding the sample is provided so that the irradiation surface is a vertical surface with respect to the ion beam or an inclined surface inclined in one direction, and the slit has a round shape for both RBS and PIXE. Or the first slit with a square opening and E
A second slit having a rectangular opening having a short side in the beam scattering direction dedicated to RDA is provided, and further, slit holding means capable of alternately installing both slits on the ion beam line is provided. Ion beam analyzer. 2. The first slit and the second slit are integrally formed as one plate piece, while the slit holding means has an ion beam having a round or square opening and a rectangular opening provided in the plate piece. The ion beam analyzer according to claim 1, wherein the ion beam analyzer is provided so as to be connected to the plate pieces so as to be alternately arranged on a line. 3. A first slit and a second slit are provided side by side adjacent to each other before and after the ion beam line, while the slit holding means is provided on both slits so that they can be alternately arranged on the ion beam line. The ion beam analyzer according to claim 1, wherein the ion beam analyzers are connected to each other. 4. The angle varying means provided on the sample stage is provided in an interlocking relationship with the slit holding means.
3. The irradiation surface is a vertical surface when the slit is arranged on the ion beam line, and the irradiation surface is an inclined surface when the second slit is arranged on the ion beam line. 3. The ion beam analyzer according to item 3.