WO2017029754A1 - Ion beam device and method for analyzing sample elements - Google Patents

Abstract

The present invention provides a practical technique for analyzing sample elements using an ion beam, wherein ultra micro-trace amounts of hydrogen and oxygen, in particular, in a sample can be detected with very high sensitivity. The present invention also provides a technique for conventionally difficult element analysis for investigating the 3D distribution of trace amounts of hydrogen and oxygen in a sample. The ion beam device of the present invention has: an ion source, an ion beam irradiation system for irradiating ions discharged from an ion source to a sample, a sample chamber for accommodating the sample, a detection system for detecting secondary ions discharged from the sample irradiated with the ion beam, an alkali metal feed system for feeding an alkali metal to the sample, and a specified-gas removal unit for removing hydrogen gas and/or oxygen gas originating in the alkali metal fed to the sample.

Description

Ion beam apparatus and sample element analysis method

The present invention relates to an ion beam apparatus and a sample element analysis method.

If the sample is irradiated with an ion beam and the secondary ions released from the sample are subjected to mass analysis, the sample surface can be subjected to elemental analysis. This is called secondary ion mass spectrometry (Secondary Ion Mass Spectrometry, hereinafter abbreviated as SIMS). Patent Document 1 discloses a SIMS device equipped with a Dioplasmatron surface ionization type cesium ion source and a side entry type liquid metal ion source as an ion source. Patent Document 2 discloses a technique for detecting a composite ion of sample element M and cesium by irradiating a sample with gallium ions and depositing neutral cesium on the sample with a SIMS apparatus.

Japanese Unexamined Patent Publication No. 5-264448 JP 2006-504090 Gazette

In conventional SIMS, three types of ion sources are mainly used. One is an oxygen plasma ion source, which is mainly used to analyze electropositive elements. At this time, positive secondary ions are detected. The other is a cesium surface ionization ion source, which is mainly used for analyzing electronegative elements, hydrogen, oxygen, carbon and the like. At this time, negative secondary ions are detected. A gallium liquid metal ion source or a gas field ion source can be used to analyze a minute portion.

In recent years, there has been an increasing need for elemental analysis of trace amounts of impurities with an extremely fine structure. In particular, it is necessary to examine a three-dimensional distribution by detecting a very small amount of hydrogen or oxygen by irradiating a very fine beam. In order to detect hydrogen and oxygen with high sensitivity, conventionally, a method of irradiating cesium ions as described above is used.

However, the surface ionization type ion source that generates cesium ions has a problem that the performance of the ion source is limited and a fine beam cannot be formed.

There was also an attempt to supply cesium to the sample in a neutral state, but hydrogen and oxygen supplied to the sample simultaneously with cesium were not sufficiently considered. That is, when supplying cesium to a sample as neutral vapor instead of ions, it is necessary to heat cesium to a temperature higher than room temperature. At this time, the inventors say that hydrogen and oxygen slightly contained in and on the surface and inside of the high-purity metal cesium, and further slight hydrogen and oxygen contained in the heated container surface and inside reach the sample surface. I found out. That is, in this case, the inventors try to detect a very small amount of hydrogen, oxygen, etc. in the sample, because a very small amount of hydrogen or oxygen is supplied as a background from the high-purity metal cesium supply system. It has been found that the problem that the lower limit of detection of hydrogen and oxygen in the inside becomes high arises. Therefore, the distribution of trace amounts of hydrogen, oxygen, etc. in the sample cannot be examined. Conventionally, when high-purity metal cesium is used when supplying cesium, it is considered that there are few impurities, and this problem has not been discovered. Although the beam can be miniaturized by using the above-described gallium liquid metal ion source and gas field ion source, the problem of oxygen and hydrogen being supplied as a background even when these are used is solved. Therefore, the detection sensitivity of hydrogen and oxygen in the sample cannot be increased.

For the reasons described above, a practical elemental analyzer that can detect a very small amount of hydrogen and oxygen in a very small portion of the sample with ultrahigh sensitivity has not been realized. Also, an elemental analysis device for examining the three-dimensional distribution of trace amounts of hydrogen and oxygen in a sample has not been realized.

The present invention has been made in view of such a situation, and in a sample element analysis apparatus using an ion beam, practical elemental analysis capable of detecting extremely small amounts of hydrogen and oxygen in a very small part of the sample, in particular, with extremely high sensitivity. Provide technology. The present invention also provides an elemental analysis technique for examining a three-dimensional distribution of trace amounts of hydrogen and oxygen in a sample, which has been difficult in the past.

In order to solve the above-described problems, an ion beam apparatus according to the present invention includes an ion source, an ion beam irradiation system that irradiates a sample with ions emitted from the ion source, a sample chamber that stores the sample, and an ion beam as a sample. A detection system for detecting secondary ions emitted from the sample upon irradiation, an alkali metal supply system for supplying alkali metal to the sample, and hydrogen gas and / or oxygen gas resulting from the alkali metal supplied to the sample A specific gas removing unit to be removed.

Further features related to the present invention will become apparent from the description of the present specification and the accompanying drawings. The embodiments of the present invention can be achieved and realized by elements and combinations of various elements and the following detailed description and appended claims.

It should be understood that the descriptions in this specification are merely exemplary, and are not intended to limit the scope of the claims or the application of the present invention in any way.

According to the present invention, it is possible to realize a practical elemental analysis that can detect a very small amount of hydrogen or oxygen in a sample with extremely high sensitivity. Further, it becomes possible to investigate a three-dimensional distribution of a trace amount of hydrogen and oxygen in a sample, which has been difficult in the past.

It is a figure which shows the schematic structural example of the ion beam elemental analyzer by embodiment of this invention. It is a figure which shows the schematic structural example of the alkali metal supply part by the 1st Embodiment of this invention. It is a figure which shows the example of the control system of the ion beam elemental analyzer by embodiment of this invention. It is a figure which shows the procedure of activation of the non-evaporable getter material with which the purification chamber is equipped. It is a figure which shows the procedure which supplies an alkali metal to the sample surface. It is a figure which shows the example of schematic structure of the alkali metal supply part by the 2nd Embodiment of this invention. It is a figure which shows the example of schematic structure of the ion beam elemental analyzer by the 3rd Embodiment of this invention.

Embodiments of the present invention provide two types of impurity removal configurations in order to remove trace amounts of hydrogen and oxygen that are supplied as a background from a high-purity alkali metal supply system. One is a first exhaust mechanism for exhausting impurities inside the storage chamber for storing the alkali metal, and the other is hydrogen remaining from the alkali metal after impurities are removed by the first exhaust mechanism and / or Alternatively, the second exhaust mechanism exhausts oxygen.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, functionally identical elements may be denoted by the same numbers. The attached drawings show specific embodiments and implementation examples based on the principle of the present invention, but these are for understanding the present invention and are not intended to limit the present invention. Not used.

This embodiment has been described in sufficient detail for those skilled in the art to practice the present invention, but other implementations and configurations are possible without departing from the scope and spirit of the technical idea of the present invention. It is necessary to understand that the configuration and structure can be changed and various elements can be replaced. Therefore, the following description should not be interpreted as being limited to this.

(1) First Embodiment <Configuration of Ion Beam Device>
FIG. 1 is a diagram illustrating a configuration example of an ion beam apparatus according to an embodiment of the present invention. Below, the 1st example of an ion beam elemental-analysis apparatus is demonstrated as an ion beam apparatus.

The ion beam elemental analyzer of this example includes a gas field ion source 1, an ion beam irradiation system column 2, a sample chamber 3, a cooling mechanism 4, a time-of-flight mass analysis column (mass spectrometer) 6, An alkali metal supply unit 30 and an ion source gas supply unit 26 are provided. Here, the gas field ion source 1, the ion beam irradiation system column 2, the sample chamber 3, the time-of-flight mass spectrometry column 6 and the like are vacuum containers. According to the ion beam elemental analyzer, it is possible to identify an element of a sample, acquire a two-dimensional distribution image of a specific element, and analyze a three-dimensional distribution.

As shown in FIG. 1, the ion beam irradiation system column 2 is, for example, installed upright with respect to the ion beam element analyzer installation surface 20, that is, the floor, and the time-of-flight mass analysis column 6 is inclined. An alkali metal supply unit 30 is attached to the sample chamber 3. The alkali metal supply unit 30 supplies an alkali metal such as lithium, sodium, potassium, rubidium, cesium, and francium to the surface of the sample 9. In the present embodiment, an example in which cesium is used as an alkali metal will be described as an example.

First, the gas field ion source 1 includes a needle-like emitter tip 21, an extraction electrode 24 provided facing the emitter tip 21 and having an opening 27 through which ions pass, a thin filament 22, It has a cylindrical filament mount 23 and a cylindrical emitter base mount 64.

Further, the gas field ion source 1 is provided with an ion source evacuation pump 12 for evacuating the vacuum vessel 15. The ion source evacuation pump 12 is connected to the vacuum container 15 through a valve 29 that can be evacuated.

Furthermore, the gas field ion source 1 includes a tilt mechanism 61 that changes the tilt of the emitter tip 21. The tilt mechanism 61 is fixed to the emitter base mount 64. This tilting mechanism 61 is used to accurately align the direction of the tip of the emitter tip with the ion beam irradiation axis 62. As in this embodiment, when the ion beam irradiation system column 2 stands upright with respect to the ion beam element analyzer installation surface 20 or floor, that is, when the gas field ion source 1 stands upright, the tilt mechanism 61 is provided. In addition, the tilt accuracy of the emitter tip 21 can be improved, and there is no drift movement in the tilt direction, so that a suitable ion element analyzer can be realized.

The gas field ion source 1 is connected to at least three kinds of gas containers. The first gas container 81 contains at least oxygen gas, the second gas container 82 contains at least one of neon, argon, xenon, and krypton, and the third gas container 83 contains either hydrogen or helium. Contains.

The ion beam irradiation system includes a focusing lens 5 that focuses the ion beam emitted from the gas field ion source 1, a pulsed electrode 7, and an objective lens 8. The focusing lens 5 and the objective lens 8 are electrostatic lenses composed of a plurality of electrodes. The pulsed electrode 7 is, for example, an opposing parallel electrode. Although not shown, the ion beam irradiation system includes a movable aperture that limits the ion beam 14 that has passed through the focusing lens 5 and a deflector that scans or aligns the ion beam that has passed through the aperture. Has been. These are used for emission pattern observation from the ion source 1 and scanning ion beam image acquisition.

The sample chamber 3 includes a sample stage 10 on which the sample 9 is placed and a charged particle detector (not shown) that detects secondary electrons emitted from the sample when the ion beam collides with the sample. And an electron gun (not shown) for neutralizing the charge-up of the sample 9. The ion element analyzer of this example further includes a sample chamber evacuation pump 13 that evacuates the sample chamber 3. In the present embodiment, a vacuum exhaust pump 52 that further contains a non-evaporable getter material 51 is provided, and a vacuum shut-off valve 53 and a heating mechanism 54 are disposed between the sample chamber 3 and the vacuum exhaust pump 52. ing.

The time-of-flight mass spectrometry column 6 is a vacuum vessel, and includes an ion lens 71 for focusing secondary ions, an ion lens 72 for imaging secondary ions, and the like. The secondary ion detector 55 includes a microchannel plate 56 and a two-dimensional electric detector. In the present embodiment, the time-of-flight mass spectrometry column 6 further includes a vacuum exhaust pump 74 that contains a non-evaporable getter material 73. This vacuum exhaust pump 74 is provided with a heating mechanism 76 (a recess for inserting the heating mechanism 76 in the vacuum exhaust pump 74) on the atmosphere side, and the heating mechanism 76 is connected to the inside of the vacuum exhaust pump 74. Has an isolated structure). Further, a valve 75 capable of shutting off the vacuum is disposed between the sample chamber 3 and the vacuum exhaust pump 74.

Furthermore, a non-evaporable getter material 77 is installed in the vicinity of the sample (inside the sample chamber 3). A heating mechanism 78 for heating the non-evaporable getter material is installed on the atmosphere side of the container of the sample chamber 3. Further, a base plate 18 is disposed on the device mount 17 disposed on the floor 20 via, for example, a vibration isolation mechanism 19. The gas field ion source 1, the ion beam irradiation system column 2, and the sample chamber 3 are supported by a base plate 18.

Next, the cooling mechanism 4 connected to the gas field ion source 1 will be described. The cooling mechanism 4 cools the inside of the gas field ion source 1 and the emitter tip 21. The cooling mechanism 4 may be a Gifford-McMahon type (GM type) refrigerator, for example. Although a Pulrus tube refrigerator can be used, in this case, a compressor unit (compressor) using helium gas as a working gas (not shown) is installed on the floor 20. The vibration of the compressor unit (compressor) is transmitted to the apparatus base 17 via the floor 20. Therefore, as described above, the vibration isolation mechanism 19 is disposed between the apparatus base 17 and the base plate 18. This makes it difficult for high-frequency vibrations of the floor to be transmitted to the field ionization ion source 1, the ion beam irradiation system column 2, the vacuum sample chamber 3, and the like. Here, the refrigerator and the compressor have been described as the cause of the vibration of the floor 20, but the cause of the vibration of the floor 20 is not limited to this, and may be a vibration due to the installation environment. Further, the vibration isolation mechanism 19 may be configured by a vibration isolation rubber, a spring, a damper, or a combination thereof.

<Detailed configuration of alkali metal supply unit>
Next, the alkali metal supply unit 30 will be described. FIG. 2 is a diagram illustrating a detailed configuration of the alkali metal supply unit 30.

The alkali metal supply unit 30 includes an alkali metal storage chamber 31 that stores the alkali metal 29 therein, a first heating mechanism 32 that heats the alkali metal storage chamber 31, an alkali metal storage chamber 31, and a first valve 37. The first exhaust section is connected to the purification chamber 34 connected to the alkali metal storage chamber 31 via the second valve 38 and removes impurities by evacuating the alkali metal storage chamber 31 and the purification chamber 34. 33, a second heating mechanism 35 for heating the purification chamber 34, and a second exhaust for removing hydrogen and / or oxygen (hydrogen or oxygen contained in the alkali metal surface or inside) remaining in the purification chamber 34. And a nozzle 40 which is connected to the purification chamber 34 via a third valve 39 and guides alkali metal to the surface of the sample 9. The purification chamber 34 is provided with an open container 41 for storing alkali metal. The first exhaust unit 33 is configured by a combination of a turbo molecular pump 42 and a dry pump 43. Further, the second exhaust part has a non-evaporable getter material 44 and a heating mechanism 45 thereof, and the hydrogen and oxygen in the purification chamber 34 are removed by heating the non-evaporable getter material 44 by the heating mechanism 45. Remove. The heating mechanism 45 is disposed in the atmosphere outside the vacuum vessel.

Further, the alkali metal storage chamber 31 is connected to the purification chamber 34 by a connecting pipe 46. Each valve can be vacuum-blocked, for example. Further, as the alkali metal 29, lithium, sodium, potassium, rubidium, cesium, and francium can be used, but cesium is used in this embodiment. Cesium is sealed in a glass ampoule because it reacts with oxygen and water.

<Ion beam miniaturization>
The tip of the emitter tip 21 of the gas field ion source 1 is formed with, for example, a nanometer-order pyramid structure by atoms. This is called the nano pyramid. Nanopyramids typically have a single atom at the tip, a layer of 3 or 6 atoms below it, and a layer of 10 or more atoms below it.

The material of the emitter tip 21 is tungsten, molybdenum fine wire, or the like. As a method of forming the nanopyramid at the tip of the emitter tip 21, a method of heating the emitter tip at a high temperature by energizing the filament after coating iridium, platinum, rhenium, osmium, palladium, rhodium, etc. In addition, there are field evaporation in vacuum, gas etching, ion beam irradiation, a remodeling method, and the like. According to such a method, an atomic nanopyramid can be formed at the tip of a tungsten wire or a molybdenum wire. For example, when a <111> tungsten wire is used, the tip is composed of one or three tungsten atoms or atoms such as iridium. In addition to this, a similar nanopyramid can be formed by etching or remodeling in vacuum at the tip of a thin wire such as platinum, iridium, rhenium, osmium, palladium, and rhodium.

Thus, the feature of the emitter tip 21 of the gas field ion source 1 according to the present embodiment is the nanopyramid (triangular pyramid shape). The strength of the electric field formed at the tip of the emitter tip 21 is adjusted (a strong electric field is formed at the tip of the emitter tip 21 by adjusting the value of the applied high voltage of several kV. The higher the voltage, the stronger the electric field. However, if the applied voltage value is equal to or higher than a predetermined value, the electric field becomes weak.) Thus, ions can be generated in the vicinity of one atom at the tip of the emitter tip. Therefore, the region from which ions are emitted, that is, the ion light source is a very narrow region, which is less than a nanometer. Thus, by generating ions from a very limited region, the beam diameter can be reduced to 1 nm or less (subnanometer). Therefore, the current value per unit area and unit solid angle of the ion source increases. This is an important characteristic for obtaining an ion beam with a fine diameter and a large current on a sample.

When a nanopyramid with one tip atom is formed using platinum, rhenium, osmium, iridium, palladium, rhodium, etc., the current emitted from the unit area / unit solid angle, that is, the ion source is similarly applied. The luminance can be increased, which is suitable for reducing the beam diameter on the sample of the ion element analyzer or increasing the current. However, when the emitter tip is sufficiently cooled and the gas supply is sufficient, it is not always necessary to form a single tip, even if the number of atoms is 3, 6, 7, 10, etc. It can demonstrate sufficient performance. In particular, when the tip is composed of 4 or more atoms and less than 10 atoms (when the tip of the emitter tip 21 is not sharpened), the ion source brightness can be increased and the tip atoms are not easily evaporated and stabilized. Operation is possible.

<Control system of ion element analyzer>
FIG. 3 is a diagram showing a configuration example in which each control system is attached to the ion element analyzer (FIG. 1) according to the embodiment of the present invention. The control system of this example includes a gas field ion source controller 91 that controls the gas field ion source 1, a cooling mechanism controller 92 that controls the cooling mechanism 4, and a lens that controls the focusing lens 5 and the objective lens 8. Control device 93, pulsed electrode control device 94, time-of-flight mass spectrometer control device 95 for controlling ion lenses 71 and 72 contained in time-of-flight mass analysis column 6, and secondary ion detector control device 96, a sample stage control device 97 for controlling the sample stage 10, a vacuum pump control device 98 for controlling the sample chamber vacuum pump 13, an ionized gas control device 191, and an alkali metal supply controller 192. And a main body control device 99 having a calculation processing capability.

The main body control device 99 is configured by a general computer and includes, for example, an arithmetic processing unit, a storage unit, an image display unit, and the like. The image display unit displays an image generated from the detection signal of the charged particle detector 11 and information input by the input unit.

The sample stage 10 includes a mechanism for linearly moving the sample 9 in two orthogonal directions within the sample placement surface, a mechanism for linearly moving the sample 9 in a direction perpendicular to the sample placement surface, and the sample 9 on the sample placement surface. It has a mechanism to rotate inside. The sample stage 10 further includes a tilt function that can vary the irradiation angle of the ion beam 14 to the sample 9 by rotating the sample 9 about the tilt axis. These controls are executed by the sample stage control device 97 in accordance with commands from the main body control device (calculation processing device) 99.

Also, the operating conditions for each part of the ion element analyzer (FIG. 1) are input from the main body controller 99. Various conditions such as an acceleration voltage at the time of generating an ion beam, an ion beam deflection width / deflection speed, a stage moving speed, and an image signal capturing timing from the image detection element are input to the main body control device 99 in advance. Then, the main body control device 99 controls the control devices for each element as a whole and serves as an interface with the user. The main body control device 99 may be composed of a plurality of computers that share roles and are connected by communication lines.

<Operation of gas field ion source>
Next, the operation of the gas field ion source 1 of this example will be described. The vacuum vessel 15 is evacuated, and after a sufficient time has elapsed, the cooling mechanism (refrigerator) 4 is operated. The emitter tip 21 is cooled by the operation of the cooling mechanism 4.

After the emitter tip 21 is cooled, a positive high voltage is applied to the emitter tip 21 as an ion acceleration voltage. Next, a high voltage is applied to the extraction electrode 24 so as to have a negative potential with respect to the emitter tip 21. Then, a strong electric field is formed at the tip of the emitter tip 21. When the ionized gas is supplied from the ionized gas supply unit 26, the ionized gas is pulled to the emitter tip surface by a strong electric field. Further, the ionized gas reaches the vicinity of the tip of the emitter tip 21 having the strongest electric field. Therefore, the ionized gas is field-ionized and an ion beam is generated.

The generated ion beam is guided to the ion beam irradiation system column 2 through the hole 27 of the extraction electrode 24. In the embodiment, argon gas is introduced as the ionized gas.

The ion beam 14 emitted from the gas field ion source 1 is focused by the focusing lens 5 and the objective lens 8 and irradiated onto the sample 9. At this time, since the diameter of the gas field ion source 1 is as small as a nanometer and the energy width of the ion beam is as small as 1 eV, if these characteristics are utilized, the diameter of the ion beam 14 on the sample 9 can be reduced. It can be as small as a sub-nanometer. In this way, the ion beam 14 can be miniaturized.

By using the gas field ion source 1, other ion sources such as a duoplasma ion source, a Penning ion source, an inductively coupled plasma (ICP) plasma ion source, and a microwave plasma (MIP: Microwave (Induced (Plasma)) It has the effect that an ion element analyzer image with higher resolution can be obtained compared to the case of using a plasma ion source.

<Operation of alkali metal supply unit>
4 and 5 are diagrams for explaining the operation of the alkali metal supply unit. FIG. 4 is a diagram showing a procedure for activating the non-evaporable getter material which is the second exhaust part 36 provided in the purification chamber 34. FIG. 5 is a diagram showing a procedure for supplying an alkali metal to the sample surface.

(Figure 4: Activation of non-evaporable getter material)
(I) Steps 101 and 102
The third valve 39 is closed, and then the first valve 37 and the second valve 38 are opened.
(Ii) Step 103
The purification chamber 34 is evacuated by the first exhaust part 33.
(Iii) Step 104
The purification chamber 34 is heated to about 150 ° C. by the second heating mechanism 35. The heating is continued for about 10 hours.
(Iv) Step 105
When the heating of the purification chamber 34 is continued for about 10 hours, the non-evaporable getter material 44 is heated to about 400 ° C. by the heating mechanism 45. The heating is continued for about 1 hour. The heating of the purification chamber 34 is continued during the heating of the non-evaporable getter material 44.
(V) Step 106
After heating the non-evaporable getter material 44 is continued for about 1 hour, heating of the non-evaporable getter material 44 and the purification chamber 34 is stopped.

By performing the above processing, the purification chamber 34 can be brought into an ultra-high vacuum state.

(Figure 5: Supply of alkali metal to the sample surface)
(I) Steps 201 and 202
The storage chamber 31 is opened to the atmosphere with the first valve 37 closed.
(Ii) Step 203
A glass ampoule containing cesium which is an alkali metal is placed in the storage chamber 31.
(Iii) Steps 204 and 205
After closing the lid of the storage chamber 31, the storage chamber 31 is evacuated by the first exhaust unit 33.
(Iv) Step 206
The glass ampule is divided in the vacuum storage chamber 31. In order to break the glass ampule, a straight line introduction mechanism or a rotation mechanism may be used.
(V) Step 207
The first valve 37 is opened to connect the storage chamber 31 and the purification chamber 34.
(Vi) Step 208
The storage chamber 31 is heated to about 200 ° C. by the first heating mechanism 32. Then, cesium becomes vapor and diffuses in the vacuum. Cesium vapor diffuses through the connecting pipe 46 to the purification chamber 34. An opening container 41 for storing cesium is disposed in the purification chamber 34 in the vicinity of the terminal end of the connection pipe 46. If the open container 41 is cooled to about 20 ° C. in advance, cesium can be efficiently condensed. Similarly, hydrogen gas, oxygen gas, nitrogen gas, water vapor, and the like diffused from the storage chamber 31 are diffused and introduced into the purification chamber 34, but are absorbed by the non-evaporable getter material 44 with high efficiency. By the above operation, cesium is highly purified and the purification chamber 34 is maintained in an ultrahigh vacuum.
(Vii) Step 209
The first valve 37 is closed.
(Viii) Steps 210 and 211
When the third valve 39 is opened and cesium is heated by the second heating mechanism 35, high-purity cesium is supplied to the surface of the sample 9 through the nozzle 40. Since the purification chamber 34 is maintained in an ultrahigh vacuum, hydrogen gas, oxygen gas, and the like hardly reach the surface of the sample 9.
(Ix) Step 212
In a state where high-purity cesium is supplied to the surface of the sample 9, the sample 9 is irradiated with an argon ion beam 14 focused to a sub-nanometer diameter.
(X) Step 213
Mass analysis of the secondary ions 16 emitted from the sample 9 is performed.

<Mass spectrometry of secondary ions>
In the present embodiment, the time-of-flight mass spectrometer 6 performs mass analysis. Therefore, the ion beam 14 is pulsed by the pulsed electrode 7 and irradiated on the sample 9. The secondary ions 16 emitted from the sample 9 by irradiating the sample 9 with the ion beam 14 are taken into the time-of-flight mass spectrometer 6. At this time, a light element such as hydrogen reaches the two-dimensional electric detector 57 early, and a heavy element such as gold arrives late. This principle (the arrival time varies depending on the element) enables elemental analysis.

As described above, by supplying cesium to the surface of the sample 9, the high secondary hydrogen and oxygen yields can be increased and the background of hydrogen and oxygen can be reduced. Sensitivity elemental analysis can be realized.

If the intensity of the electric field formed at the tip of the emitter tip 21 is adjusted to reduce the size of the ion beam 14, the ion beam 14 is focused on the sub-nanometer diameter and scanned while irradiating the sample 9 with the sub-nanometer resolution. The two-dimensional elemental distribution image can be obtained. Further, when scanning is continued by irradiating the gas ion beam 14, the sample 9 can be shaved in the depth direction of the sample 9 over time. In this way, the three-dimensional element distribution analysis of the elements in the sample 9 can be performed. In particular, it was found that when a neon beam or an argon beam is used, the amount of hydrogen remaining in the background can be reduced to perform highly sensitive analysis. That is, the inventors have a strong electric field when extracting ions, and impurity ions such as hydrogen do not reach the tip of the emitter tip 21 and emit in a direction greatly deviated from the direction of the sample 9. I found out. In other words, the hydrogen ion beam is applied to the sample 9 and embedded in the sample 9 to prevent the hydrogen from being detected. Thus, since high purity cesium is supplied to the surface of the sample 9, the effect of improving the negative secondary ion collection efficiency of hydrogen and oxygen and the effect of reducing the amount of hydrogen gas and oxygen gas to a very small amount By this, ultrasensitive analysis of hydrogen and oxygen is realized. Further, since the diameter of the argon ion beam is focused on the bunameter, an extremely fine two-dimensional element distribution image can be obtained, and the three-dimensional element distribution analysis can be performed.

Conventionally, reduction of a large amount of impurities when reducing cesium chromate to generate cesium vapor has been a problem, and it has been considered that the problem can be solved by using pure metal. And it was based on the vacuum degree of a sample chamber not deteriorating. However, even when pure metal is used, the inventors have found that a very small amount of hydrogen gas, oxygen gas, water vapor, etc. impedes high-sensitivity analysis in order to increase the background when analyzing hydrogen or oxygen. It was. That is, heating is performed when cesium is evaporated and transported to the surface of the sample 9. At this time, a small amount of hydrogen gas, oxygen gas, water vapor or the like is generated from the container or cesium and supplied to the surface of the sample 9 simultaneously with cesium. It will be done. It was a newly discovered fact that the subject was not conceived even when the degree of vacuum in the sample chamber 3 was measured.

<Operational effect of non-evaporable getter material provided near the sample>
In the present embodiment, as shown in FIG. 1, a non-evaporable getter material 77 is disposed in the vicinity of the sample 9 (in the sample chamber). For this reason, when hydrogen gas, oxygen gas, etc. were adsorbed by the non-evaporable getter material 77, it was found that the concentration of hydrogen or oxygen existing in the background is lowered and high sensitivity analysis is realized. A heating mechanism 78 for the non-evaporable getter material is installed on the atmosphere side of the sample chamber container so that the non-evaporable getter material 77 can be reactivated. That is, there is an effect that a state in which high sensitivity analysis is possible can be continued for a long time.

<Effect of vacuum pump connected to sample chamber and containing non-evaporable getter material>
In the present embodiment, as shown in FIG. 1, a vacuum exhaust pump 52 that contains a non-evaporable getter material 51 is connected to the sample chamber 3 via a valve 53 that can be vacuum-blocked. In the case of adopting such a configuration, although the exhaust conductance becomes low, the same effect as when the non-evaporable getter material 51 is arranged in the vicinity of the sample 9 can be obtained.

Furthermore, when oxygen ions are selected as the primary ions 14 when the sample 9 is irradiated, the valve 53 that can be shut off by vacuum is closed. In the opened state, the non-evaporable getter material 51 adsorbs oxygen gas, so the time until the non-evaporable getter material 51 is reactivated is shortened. However, the valve 53 that can shut off the vacuum can be closed. This is because the time until the non-evaporable getter material 51 is reactivated can be lengthened. That is, there is an effect that a state in which high sensitivity analysis can be performed efficiently can be continued for a long time.

<Effect of vacuum pump connected to mass spectrometer and containing non-evaporable getter material>
In this embodiment, the mass spectrometer 6 is connected to a vacuum exhaust pump 74 containing a non-evaporable getter material 73 via a valve 75 that can be shut off by vacuum. Conventionally, hydrogen gas and oxygen gas diffused from the material analyzer 6 and supplied to the surface of the sample 9 have not been considered.

However, when the evacuation pump 74 including the non-evaporable getter material 73 is operated, the amount of hydrogen and oxygen present in the background is reduced, and high sensitivity analysis of hydrogen and oxygen present in the sample 9 is realized. Will be able to.

In the above case, as shown in FIG. 1, the ion beam irradiation system column 2 for supplying the irradiation ion beam stands upright with respect to the ion beam elemental analyzer installation surface 20, that is, the floor, and connects the secondary ion beam. The ion detection system column (time-of-flight mass spectrometry column) 6 to be imaged is installed at an inclination. With such a structure, the structural distortion of the ion beam irradiation system is small, the aberration of the lens is small, and the extremely fine ion beam 14 is directed toward the sample 9. As a result, it was found that the resolution of the two-dimensional element distribution image was increased.

<Projection mass spectrometry>
In the time-of-flight mass spectrometer 6 according to the present embodiment, projection mass spectrometry is performed. That is, the secondary ions 16 emitted from the sample 9 are imaged on the microchannel plate 56 by the two ion lenses 71 and 72. Then, the two-dimensional signal intensity of the microchannel plate is output as an image signal. However, the ion beam 14 does not necessarily have to scan over the sample 9. In the present embodiment, a time-of-flight mass spectrometer is used as the mass spectrometer 6. However, a quadrupole mass spectrometer and a sector mass spectrometer can be applied.

<Types of ion gas>
Although argon ions are used in this embodiment, similar effects can be obtained by using xenon, krypton, or the like. In addition, when xenon or krypton is used, it is possible to expect an effect that the magnetic field noise is not particularly affected. Further, it may be a mixed gas including a plurality of gas types such as two types of mixed gases and three types of mixed gases.

In this embodiment, the gas field ion source 1 is connected to at least three gas containers. The first gas container 81 contains at least oxygen gas, the second gas container 82 contains at least one of neon, argon, xenon, and krypton, and the third gas container 83 contains either hydrogen or helium. It is out.

In this way, if the oxygen gas in the first gas container 81 is used, the sample 9 is irradiated with an oxygen gas ion beam, and positive secondary ions are detected, thereby realizing highly sensitive analysis of electropositive elements. can do. In addition, any one of neon, argon, xenon, and krypton in the second gas container 82 is used. Then, while supplying alkali metal from the alkali metal supply unit 30 to the sample, the sample 9 is irradiated with the gas ion beam 14 to detect negative secondary ions, thereby detecting high sensitivity of hydrogen and oxygen contained in the sample 9. Analysis can be realized. Furthermore, if secondary electrons are detected by irradiating the sample 9 with an ion beam 14 of either hydrogen or helium in the third gas container 83, a scanned ion image of the surface of the sample 9 can be obtained without damaging the sample. Obtainable. In other words, an elemental analyzer that can obtain structural information and elemental information on the surface of the sample 9 is provided.

In the ion beam apparatus (ion beam elemental analysis apparatus) according to the present embodiment, a mixed gas container containing a plurality of gas types such as two kinds of mixed gases or three kinds of mixed gases may be used. Gas may be used alternately.

(2) Second Embodiment The ion beam elemental analyzer according to the second embodiment differs from that according to the first embodiment in the configuration of the alkali metal supply unit 30. Other configurations are the same as those of the ion beam element analyzer (FIG. 1) according to the first embodiment.

<Configuration of alkali metal supply unit>
FIG. 6 is a diagram illustrating a configuration example of the alkali metal supply unit 30 according to the second embodiment.

The alkali metal supply unit 30 includes an alkali metal storage chamber 31 that stores the alkali metal 29 therein, a first heating mechanism 32 that heats the alkali metal storage chamber 31, an alkali metal storage chamber 31, and a first valve 37. A purification chamber 34 that is connected to each other, a first exhaust part 33 that is connected to the alkali metal storage chamber 31 via a second valve 38 and removes impurities by evacuating the alkali metal storage chamber 31, and purification. A second heating mechanism 35 for heating the chamber 34, a second exhaust part 36 for removing hydrogen and / or oxygen remaining in the purification chamber 34 (hydrogen or oxygen contained in the alkali metal surface or inside), A nozzle 40 that is connected to the purification chamber 34 via a third valve 39 and guides alkali metal to the surface of the sample 9, and a third exhaust unit 4 that is connected to the purification chamber 34 via a fourth valve 48. And, the has.

In the alkali metal storage chamber 31, an alkali metal (for example, rubidium) 29 is placed on the metal net 47. The purification chamber 34 is provided with an open container 41 for storing the alkali metal 29. The first exhaust part 33 is configured by, for example, a combination of a turbo molecular pump 42 and a rotary pump 50. The second exhaust part 36 includes a non-evaporable getter material 44 and a heating mechanism 45 thereof. As described above, the heating mechanism 45 is disposed in the atmosphere outside the vacuum vessel. Each valve can be vacuum shut off.

As the alkali metal, lithium, sodium, potassium, rubidium, cesium, and francium can be used. In this embodiment, for example, rubidium is used.

The non-evaporable getter material 44 that is the second exhaust part 36 provided in the purification chamber 34 is brought into an ultra-high vacuum state by an activation procedure similar to that of the first embodiment. In the present embodiment, the purification chamber 34 can be directly evacuated using the third exhaust part 49 connected to the purification chamber 34 via the fourth valve 48.

<Purification treatment of alkali metal>
Next, the process for purifying the alkali metal executed in the alkali metal supply unit 30 according to the present embodiment will be described.

First, the storage chamber 31 is opened to the atmosphere with the first valve 37 closed. Since rubidium 29, which is an alkali metal, reacts with oxygen, water, and the like, in this embodiment, it is disposed on the metal net 47 in the storage chamber in a nitrogen purged atmosphere.

Next, the second valve 38 is opened, and the storage chamber 31 is evacuated by the first exhaust part 33. Then, the storage chamber 31 is heated to about 50 ° C. by the first heating mechanism 32. Then, rubidium 29 melts. When the rubidium 29 is dissolved, the first valve 37 is opened and the storage chamber 31 and the purification chamber 34 are connected. The melted rubidium 29 passes through the connecting pipe 46 and falls to the purification chamber 34.

In the purification chamber 34, an open container 41 for storing rubidium is disposed in the vicinity of the terminal end of the connecting pipe 46. When the rubidium 20 is supplied from the storage chamber 31 to the purification chamber 34, hydrogen gas, oxygen gas, nitrogen gas, water vapor, and the like are also diffused from the storage chamber 31 and introduced into the purification chamber 34. However, these gases are absorbed with high efficiency by the non-evaporable getter material 44.

By the above operation, the rubidium 29 is highly purified, and the purification chamber 34 is maintained in an ultra-high vacuum.

Then, when the third valve 39 is opened and the rubidium 29 is heated by the second heating mechanism 35, the high-purity rubidium 29 is supplied to the surface of the sample 9 through the nozzle 40. At this time, the hydrogen gas and oxygen gas generated in the purification chamber 34 are absorbed by the non-evaporable getter material 44, so that these gases hardly reach the sample 9.

<About elemental analysis>
In a state where high-purity rubidium 29 is supplied to the surface of the sample 9, the sample 9 is irradiated with the argon ion beam 14 to detect secondary ions emitted from the sample 9. In this way, ultra-sensitive elemental analysis of hydrogen and oxygen contained in the sample 9 can be performed by the effect of increasing the negative secondary ion yield of hydrogen and oxygen and the effect of reducing the background of hydrogen and oxygen. Can be realized.

If the ion beam 14 is made finer by adjusting the electric field strength formed at the tip of the emitter tip 21, focused with a subnanometer diameter, and scanned while irradiating the sample 9 with the ion beam 14, the subnanometer resolution can be obtained. The two-dimensional elemental distribution image can be obtained. Furthermore, if the scanning is continued by irradiating the sample 9 with the gas ion beam 14, the sample 9 can be shaved in the depth direction as time passes. In this way, the three-dimensional element distribution analysis of the elements in the sample 9 can be performed.

It should be noted that the activation of the non-evaporable getter material 44 built in the purification chamber 34 can also be performed using the fourth valve 48 and the third exhaust part 49. That is, the hydrogen generated from the non-evaporable getter material 44 when the non-evaporable getter material 44 is heated by the heating mechanism 45 and the first valve 37 and the third valve 39 are closed and the fourth valve 48 is opened. Gas, oxygen gas, or the like is exhausted by the third exhaust unit 49. After the reactivation, the fourth valve 48 is closed. By doing so, the non-evaporable getter material 44 can be activated.

(3) Third Embodiment An ion beam apparatus according to the third embodiment has an alkali metal ion irradiation system column 200 in place of the alkali metal supply unit 30 in the first and second embodiments. Yes.

<Configuration of ion beam device>
FIG. 7 is a diagram illustrating a configuration example of the ion beam apparatus according to the third embodiment. Hereinafter, an ion beam element analyzer will be described as an example of the ion beam apparatus.

The ion beam elemental analyzer of this example includes a gas field ion source 1, an ion beam irradiation system column 2, a sample chamber 3, a cooling mechanism 4, a time-of-flight mass spectrometry column 6, and a cesium ion irradiation system column. 200 and an ion source gas supply unit 26. Here, the gas field ion source 1, the ion beam irradiation system column 2, the sample chamber 3, the time-of-flight mass spectrometry column 6, the cesium ion irradiation system column 200, and the like are vacuum containers. According to the ion beam elemental analysis apparatus, it is possible to identify an element of the sample 9, obtain a two-dimensional distribution image of a specific element, and analyze a three-dimensional distribution.

The operation of the gas field ion source, the operation of the ion beam irradiation system, the operation of the mass spectrometer, and the like are the same as in the first embodiment. In the present embodiment, neon is used as the gas ion species with which the sample 9 is irradiated.

As shown in FIG. 7, the ion beam irradiation system column 2 stands upright with respect to the ion beam element analyzer installation surface 20, that is, the floor, and the time-of-flight mass analysis column 6 is inclined. In the cesium ion irradiation system column 200, the angle of the irradiation direction from the surface of the sample 9 is preferably 0 degrees or more and at most 10 degrees so that the irradiation direction of the cesium ion beam is substantially parallel to the surface of the sample 9. It is arranged to be as follows.

The cesium ion irradiation system column 200 includes a cesium liquid metal ion source 201, an ion potential electrode 202, a focusing lens 203, an objective lens 204, and the like. For example, a positive 0.5 kV is applied to the cesium liquid metal ion source 201, and a negative 3 kV is applied to the ion potential electrode 202. In this way, the sample 9 is irradiated with cesium ions having a low energy of 0.5 kV. When the ion beam with low energy is irradiated almost parallel to the surface of the sample 9 as in this embodiment, the unevenness of the surface of the sample 9 formed by the neon ion beam irradiated from the vertical direction is eliminated, and The inventors have found that an appropriate amount of cesium is supplied to the surface of the sample 9. That is, the inventors found that the yield of negative secondary ions of hydrogen and oxygen increases because an appropriate amount of cesium is supplied to the sample 9.

Conventionally, since secondary ions generated when the sample 9 was irradiated with the cesium ion beam were detected, elemental analysis of a very small portion of the sample 9 was difficult. Even if the sample 9 is irradiated with cesium and gallium ions in advance, the sensitivity of the first surface layer increases, but the sensitivity decreases thereafter, and highly sensitive depth analysis and three-dimensional analysis are realized. It wasn't.

According to the third embodiment, since the cesium concentration can always be kept in an optimum state, the cesium concentration can be adjusted so that the sensitivity of hydrogen and oxygen does not change. Further, the sample 9 is irradiated with cesium with extremely low energy using an ion potential electrode. For this reason, the effect that the sputter damage by cesium ion can be reduced can be expected. The same effect can be obtained with lithium, sodium, potassium, rubidium, and francium, which are alkali metals other than cesium. It was also found that when argon was used in addition to neon, the ion source generated an ion beam of hydrogen and oxygen with less sensitivity, enabling ultra-high sensitivity analysis.

As described above, in the third embodiment, the gas field ion source 1, the ion beam irradiation system that irradiates the sample 9 with the gas ion beam 14 emitted from the ion source 1, and the ions that irradiate the sample 9 with alkali metal ions. When the beam irradiation system and the sample chamber 3 for storing the sample 9 and the alkali metal ion beam can be irradiated to the sample 9 from a substantially parallel direction, the gas ion beam 14 is irradiated to the sample 9 from a substantially vertical direction. And an ion beam elemental analysis apparatus having a system capable of detecting secondary ions emitted from a sample 9. In this way, when the sample 9 is irradiated with a gas ion beam from a substantially vertical direction and the sample 9 is three-dimensionally analyzed, irregularities are generated on the surface of the sample 9 by ion sputtering. Therefore, the unevenness on the surface of the sample 9 can be reduced by irradiating the sample 9 with the alkali metal ion beam from a substantially parallel direction. That is, it is possible to expect an effect that distortion can be reduced when three-dimensional reconstruction is performed from the analysis result. In addition, the secondary ion yield of hydrogen and oxygen is increased, and the detection sensitivity of hydrogen and oxygen is improved.

<Effects of non-evaporable getter material placed in sample chamber>
In the ion beam apparatus, a non-evaporable getter material 77 is installed in the vicinity of the sample 9 placed in the sample chamber 3. A heating mechanism 78 for heating the non-evaporable getter material 77 is installed on the atmosphere side of the container of the sample chamber 3.

In this apparatus, since hydrogen gas, oxygen gas, and the like are adsorbed by the non-evaporable getter material 77, the concentration of hydrogen and oxygen present in the background decreases, and the hydrogen and oxygen contained in the sample 9 are analyzed with high sensitivity. It becomes possible. A heating mechanism 78 for the non-evaporable getter material 77 is installed on the atmosphere side of the container of the sample chamber 3. Thereby, the non-evaporable getter material 77 can be reactivated. That is, there is an effect that a state in which high sensitivity analysis is possible can be continued for a long time.

(4) Summary of Embodiment (i) The ion beam apparatus (ion beam elemental analysis apparatus) according to the present embodiment has a supply unit for supplying an alkali metal to a sample. The supply unit includes a first exhaust unit and a second exhaust unit (specific gas removal unit) that exhausts hydrogen gas or oxygen gas after the operation of the first exhaust unit. By doing so, it is possible to provide a practical ion beam apparatus that can detect a very small amount of hydrogen and oxygen with extremely high sensitivity. In particular, impurity gas generated from the atmosphere and alkali metal in the supply unit is exhausted by the first exhaust unit. Further, a very small amount of hydrogen gas or oxygen gas (specific gas) is exhausted by the second exhaust unit. For this reason, it becomes possible to supply an alkali metal, supplying almost no hydrogen gas or oxygen gas to a sample. Therefore, analysis is possible in a situation where the background of hydrogen and oxygen secondary ions is low and the yield of negative secondary ions of hydrogen and oxygen is large. Therefore, a very small amount of hydrogen and oxygen contained in the sample can be detected with extremely high sensitivity.

The second exhaust part may include a non-evaporable getter material. Impurity gas generated from the atmosphere and alkali metal in the supply unit is exhausted by the first exhaust unit, and further generated from a container or the like when pure alkali metal is heated by the non-evaporable getter material contained in the second exhaust unit Remove hydrogen gas and oxygen gas. Since the non-evaporable getter material has a high exhaust rate (removal) of hydrogen gas or oxygen gas, hydrogen and oxygen gas can be reduced, and the secondary ion background can be lowered. Therefore, a very small amount of hydrogen and oxygen contained in the sample can be detected with extremely high sensitivity.

The supply unit has a purification chamber and a storage chamber for storing alkali metal. The purification chamber and the sample chamber are connected by a first valve, and the storage chamber and the purification chamber are connected by a second valve, respectively. First, a material containing an alkali metal is disposed in the storage chamber, and the alkali metal is stored in a vacuum by exhausting the impurity gas generated from the atmosphere and the alkali metal in the storage chamber with the second valve closed. Next, the alkali metal is evaporated by heating with the first valve opened and the second valve closed. Thereby, a part of alkali metal can be moved to the purification chamber. And since the 2nd exhaust part contains a non-evaporable getter material, when heating a pure alkali metal, hydrogen gas and oxygen gas which generate | occur | produce from a container etc. can be removed. Note that a non-evaporable getter material and a heating unit may be provided inside the purification chamber. Thus, after the purification chamber is exhausted by the first exhaust part, the non-evaporable getter material in the second exhaust part can be heated and activated. That is, it becomes possible to keep the exhaust speed of the non-evaporable getter material with respect to hydrogen gas and oxygen gas at a high level.

The ion source may be a gas field ion source. The sample can be irradiated with a gas ion beam emitted from a gas field ion source. In particular, two-dimensional and three-dimensional elemental analysis can be performed by irradiating a sample with an extremely fine gas ion beam. That is, it becomes possible to investigate the three-dimensional distribution of extremely small amounts of hydrogen and oxygen. In addition, the sample is less damaged than when a conventional gallium metal is used, which is suitable for examining the structure of the sample.

In the ion beam apparatus, the gas field ion source is connected to at least three kinds of gas containers. The first gas container contains at least oxygen gas, the second gas container contains at least one of neon, argon, xenon, and krypton, and the third gas container contains either hydrogen or helium. Thereby, various types of gas ion beams can be irradiated onto the sample from the gas field ion source. For example, if oxygen gas in the first gas container is used, highly sensitive analysis of an electropositive element can be realized by irradiating the sample with an oxygen gas ion beam and detecting positive secondary ions. Using a gas of neon, argon, xenon, or krypton in the second gas container and irradiating the sample with a gas ion beam while supplying alkali metal from the alkali metal supply unit to the sample, negative secondary By detecting ions, a highly sensitive analysis of hydrogen and oxygen can be realized. Furthermore, if a secondary electron is detected by irradiating the sample with either an ion beam of hydrogen or helium in a third gas container, a scanned ion image of the sample surface can be obtained without damaging the sample. That is, structural information and element information on the sample surface can be obtained.

(Ii) In the ion beam apparatus according to the present embodiment, as described above, a non-evaporable getter material for removing a trace amount of hydrogen gas or oxygen gas (specific gas) may be disposed in the supply unit. Separately or in addition, a container for storing the non-evaporable getter material may be connected to the sample chamber. Even in this case, the hydrogen gas and oxygen gas in the sample chamber can be exhausted at high speed by the non-evaporable getter material, the hydrogen and oxygen gas can be reduced, and the secondary ion background can be lowered. Therefore, a very small amount of hydrogen and oxygen contained in the sample can be detected with extremely high sensitivity. The container for storing the non-evaporable getter material and the sample chamber are connected via a valve. Thus, if the valve is closed during elemental analysis other than hydrogen and oxygen analysis, the activation interval of the non-evaporable getter material can be lengthened. That is, an efficient operation of the apparatus is realized.

(Iii) In the ion beam apparatus according to the present embodiment, as described above, a non-evaporable getter material for removing a trace amount of hydrogen gas or oxygen gas (specific gas) is disposed in the supply unit, and the non-evaporable getter is disposed in the sample chamber. A container for storing the material may be connected. Alternatively, or in addition thereto, a non-evaporable getter material may be installed in the sample chamber (near the sample). Even in this case, the hydrogen gas and oxygen gas in the sample chamber can be reduced, and the secondary ion background can be lowered. Then, if the gas ion beam emitted from the gas field ion source is finely bundled and irradiated on the sample, ultra-sensitive two-dimensional and three-dimensional elemental analysis of hydrogen and oxygen becomes possible.

(Iv) The ion beam apparatus according to the present embodiment is emitted from the sample, the ion beam irradiation system for irradiating the sample with the gas ion beam emitted from the ion source, the ion beam irradiation system for irradiating the sample with alkali metal ions. And a system capable of detecting secondary ions. The alkali metal ion beam can be irradiated from the substantially parallel direction to the sample, and the gas ion beam is irradiated from the substantially vertical direction to the sample. When performing a three-dimensional analysis of a sample by irradiating the sample with a gas ion beam from a substantially vertical direction, there is a problem that irregularities due to ion sputtering occur on the sample surface. Therefore, the unevenness of the sample surface can be reduced by irradiating the sample with an alkali metal ion beam from a substantially parallel direction. That is, there is an effect that distortion can be reduced when three-dimensional reconstruction is performed from the analysis result.

(V) Sample element analysis in the present embodiment is performed by irradiating a sample with a gas ion beam, evaporating an alkali metal raw material, adsorbing hydrogen or oxygen by a non-evaporated getter material, and supplying an alkali metal vapor to the sample. , And irradiating the sample with a gas ion beam to detect secondary ions emitted from the sample. By doing so, when supplying the alkali metal vapor to the sample, hydrogen and oxygen are rarely supplied to the sample, so that hydrogen and oxygen in the sample can be analyzed with ultra-high sensitivity. Note that any one of cesium, lithium, and sodium can be used as the alkali metal.

1 gas field ion source, 2 ion beam irradiation system column, 3 sample chamber, 4 cooling mechanism, 5 focusing lens, 6 time-of-flight mass spectrometry column, 7 pulsed electrode, 8 objective lens, 9 sample, 10 sample stage, 11 charged particle detector, 12 ion source evacuation pump, 13 sample chamber evacuation pump, 14 ion beam (gas ion beam), 15 vacuum vessel, 16 secondary ion, 17 device mount, 18 base plate, 19 vibration isolation Mechanism, 20 floor (ion beam element analyzer installation surface), 21 emitter tip, 22 filament, 23 filament mount, 24 extraction electrode, 26 ion source gas supply section, 29 alkali metal, 30 alkali metal supply section, 31 alkali metal storage Chamber, 32 first heating mechanism, 33 first exhaust section, 34 purification chamber, 35 second chamber Heat mechanism, 36 Second exhaust part, 37 First valve, 38 Second valve, 39 Third valve, 40 Nozzle for introducing alkali metal to sample surface, 41 Open container, 42 Turbo molecular pump, 43 Dry pump , 44 Non-evaporable getter material, 45 Heating mechanism, 46 Connecting pipe, 47 Metal mesh, 48 Fourth valve, 49 Third exhaust part, 50 Rotary pump, 51 Non-evaporable getter material, 52 Vacuum exhaust pump, 53 Vacuum shut-off Possible valve, 54 heating mechanism, 55 secondary ion detector, 56 micro-channel plate, 57 two-dimensional electric detector, 61 tilt mechanism, 62 ion beam irradiation axis, 64 emitter base mount, 71 ion lens, 72 ion lens, 73 Non-evaporable getter material, 74 Vacuum pump, 75 Vacuum shut-off valve, 76 Non-evaporable getter material heating mechanism , 77 Non-evaporable getter material, 78 Heating mechanism of non-evaporable getter material, 81 First gas container, 82 Second gas container, 83 Third gas container, 91 Gas field ionization ion source controller, 92 Cooling mechanism control Equipment, 93 lens control device, 94 pulsed electrode control device, 95 time-of-flight mass spectrometer control device, 96 secondary ion detector control device, 97 sample stage control device, 98 vacuum pump control device, 99 main body control Device, 191 ionization gas control device, 192 alkali metal supply control device, 200 cesium ion irradiation system column, 201 cesium liquid metal ion source, 202 ion potential electrode, 203 focusing lens, 204 objective lens

Claims (15)

1. An ion source;
   An ion beam irradiation system for irradiating the sample with an ion beam emitted from the ion source;
   A sample chamber for storing the sample;
   A detection system for irradiating the sample with the ion beam to detect secondary ions emitted from the sample;
   An alkali metal supply system for supplying an alkali metal to the sample;
   A specific gas removing unit that removes hydrogen gas and / or oxygen gas caused by the alkali metal supplied to the sample;
   An ion beam apparatus.
2. In claim 1,
   The specific gas removal unit is included in the alkali metal supply system,
   The alkali metal supply system further includes an exhaust section for exhausting the alkali metal supply system,
   The said alkali metal supply system is an ion beam apparatus which removes the hydrogen gas and / or oxygen gas resulting from the said alkali metal by the said specific gas removal part after the action | operation of the exhaust operation by the said exhaust part.
3. In claim 1,
   The specific gas removing unit is an ion beam apparatus including a non-evaporable getter material.
4. In claim 2,
   The alkali metal supply system is connected to the exhaust unit via a first valve, and is connected to a storage chamber for storing alkali metal and the storage chamber via a second valve, thereby purifying the alkali metal. And an ion beam apparatus.
5. In claim 4,
   The specific gas removal unit includes a non-evaporable getter material and a heating unit that heats the non-evaporable getter material,
   The non-evaporable getter material is an ion beam device installed in the purification chamber.
6. In claim 1,
   The ion beam device is a gas field ion source.
7. In claim 6,
   The gas field ion source is connected to at least three gas containers;
   The first gas container contains at least oxygen gas,
   The second gas container contains at least one gas selected from neon, argon, xenon, and krypton,
   The third gas container is an ion beam apparatus including one of hydrogen and helium.
8. In claim 1,
   The specific gas removing unit is an ion beam apparatus attached to the sample chamber.
9. In claim 1,
   The ion source is a gas field ion source;
   The ion beam irradiation system irradiates the sample with the ion beam from a substantially vertical direction,
   The said alkali metal supply system is an ion beam apparatus which irradiates the said alkali metal ion beam with respect to the said sample from a substantially parallel direction.
10. In claim 9,
    The specific gas removing unit includes an non-evaporable getter material and is installed inside the sample chamber.
11. In claim 9,
    A mass spectrometer column that analyzes the mass of secondary ions emitted from the sample by irradiating the sample with an ion beam;
    The ion beam apparatus, wherein the mass spectrometer column is inclined with respect to the ion beam apparatus installation surface.
12. A gas field ion source;
    An ion beam irradiation system for irradiating a sample with an ion beam emitted from the gas field ion source;
    A sample chamber for storing the sample;
    A system capable of detecting secondary ions emitted from the sample by irradiating the ion beam;
    An ion beam apparatus comprising a non-evaporable getter material installed in the vicinity of the sample.
13. In claim 12,
    A non-evaporable getter material is contained in a container, and the container is connected to the sample chamber via a valve.
14. Irradiating the sample with a gas ion beam;
    Evaporating alkali metal to produce alkali metal vapor;
    Adsorbing hydrogen or oxygen with a non-evaporable getter material;
    Supplying the alkali metal vapor to the sample;
    Irradiating the sample with the gas ion beam to detect secondary ions emitted from the sample;
    A sample elemental analysis method including:
15. In claim 14,
    The sample elemental analysis method, wherein the alkali metal is any one of cesium, lithium, sodium, and potassium.

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