JPH06132007A - Exb type mas separator - Google Patents

Abstract

PURPOSE:To simplify and miniaturize a mass separator added with separating and removing function of neutral particles. CONSTITUTION:A vacuum chamber 21, serving as a beam passageway, is composed of an opposing wall 211 made of a magnetic material and an opposing wall 212, attached thereto via an insulator 26, made of a non-magnetic material. The opposing wall 21, made of a magnetic material is attched to a magnetic path 23 containing an exciting coil 22, which serves as a magnetic pole. The opposing wall 212 made of a non-magnetic material serves as an electrode for forming an electric field. Further, providing an insulator in the magnetic path 23 electrically insulates the opposing wall 211 made of a magnetic material. When applying a DC voltage across the opposing wall 211 made of a magnetic material so as to form an electric field between the opposing walls, any ion of a desired mass can be deflected in the electric filed's direction, so that a function of the separation of ions and neutral particles introduced in the vacuum chamber and the removal of the neutral particles can be added.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an E.times.B type mass separator which has a function of reducing the size of a vacuum chamber which serves as a beam passage and has a function of separating and removing neutral particles.

[0002]

2. Description of the Related Art An E × B type mass separator (E cross B type mass separator, also known as Wien filter) utilizing an electric field E and a magnetic field B which are orthogonal to each other is a molecular beam epitaxy (MBE).
It is used as a means for separating and extracting ions of a desired mass in a low-energy ion gun or an irradiation device attached to the apparatus, a primary optical system in a secondary ion mass spectrometer, and the like.

FIG. 4 is a basic configuration diagram of a low energy ion irradiation apparatus using an E × B type mass separator. The ion beam extracted from the ion source 1 is an E × B type mass separator 2
Will be introduced to. Ions of the desired mass go straight through the separator and pass through the analysis slit 3. As with the ions of desired mass, neutral particles that have entered straight into the separator 2 also go straight through and pass through the analysis slit 3, so an electrostatic deflector 4 for removing neutral particles is provided downstream of the slit. , Only the desired ion beam is slightly deflected, and the target 5
Irradiate and inject.

FIG. 5 is a cross-sectional view showing an example of the E × B type mass separator 2, which relates to the invention by the present inventors who had previously applied for a patent (Japanese Patent Application No. 4-119940).
issue). The vacuum chamber 21 serving as a beam passage is formed of a facing wall 21 ₁ made of a magnetic material and a facing wall 21 ₂ made of a non-magnetic material. The opposing wall 21 ₁ of the magnetic steel is coupled magnetic path 23 having the exciting coil 22 of the magnetomotive force source, the opposing wall forms a uniform magnetic field in the chamber 21 by energizing the exciting coil It works as a magnetic pole. in this way,
Since the magnetic pole, which has been provided separately from the vacuum chamber that serves as the beam passage, is configured as a part of the vacuum chamber 21, the chamber and the magnetic pole are downsized, and the magnetic gap is shortened. Since the magnetomotive force can be reduced, including the magnetic path having the magnetomotive force source,
The entire mass separator can be miniaturized. In order to form an electric field orthogonal to the magnetic field in the vacuum chamber 21,
A parallel plate electrode 24 is provided in parallel with the opposing wall 21 ₂ made of a non-magnetic material.
Is provided, and a DC voltage for forming an electric field is applied to the electrode via a feedthrough terminal 25 provided on a non-magnetic opposed wall.

[0005]

As described above, in the E × B type mass separator 2, since the parallel plate electrode 24 for forming an electric field is installed in the vacuum chamber 21 so as to be insulated from the chamber, the beam passage path is not provided. Becomes narrower, and accordingly, the vacuum chamber must be provided with a feed-through terminal 25 for power supply, which complicates the entire structure.

Further, with respect to the E × B type mass separator 2, the action force of the magnetic field and the action force of the electric field with respect to the ions of the desired mass are balanced based on the usual usage thereof, and as shown in FIG. When the mass separation is carried out so as to go straight, if the neutral particles are introduced into the mass separator, in order to remove the neutral particles and separate the ions and the neutral particles of the desired mass, The electrostatic deflector 4 must be provided as a separate mechanism, which increases the size of the entire ion irradiation apparatus.

An object of the present invention is to provide an E × B type mass separator in which the mass separation mechanism is simplified and miniaturized, and further, separation of ions of a desired mass from neutral particles and neutral particles. The purpose of the present invention is to provide an E × B type mass separator that also has a removal function of

[0008]

The present invention relates to an E × B type mass separator having a vacuum chamber having a rectangular cross section which serves as a beam passage, and is made of a magnetic material coupled to a magnetic path having a magnetomotive force source. It is characterized by comprising a facing wall and the vacuum chamber composed of a facing wall made of a non-magnetic material and electrically coupled to the facing wall and to which a direct current voltage is applied.

Further, according to the present invention, the opposing wall made of a magnetic material and coupled to the magnetic path having the magnetomotive force source is electrically insulated by an insulator provided in the magnetic path. Is also characterized in that a DC voltage is applied.

[0010]

The vacuum chamber having a rectangular cross section which serves as a beam passage is composed of a magnetic opposing wall and a non-magnetic opposing wall electrically insulated and coupled to the magnetic opposing wall. In addition to making the opposing wall made of a body function as a magnetic pole for forming a magnetic field, the opposing wall made of a non-magnetic body can be made to function as an electrode for forming an electric field, and a parallel plate electrode is provided separately from the chamber. Since it is not necessary to provide the beam passage of a sufficient size in the vacuum chamber, the structure of the chamber and the electromagnetic field forming unit can be simplified and downsized. Further, since a DC voltage for forming an electric field can be directly applied to the opposing wall made of a non-magnetic material from the atmosphere, it is not necessary to provide a feedthrough terminal in the vacuum chamber.

Further, a DC voltage is applied to the opposing walls made of a magnetic material to form an electric field between the walls. Along with this, of the ions and neutral particles having a desired mass that travel straight, the ions are deflected in the direction of the electric field between the opposing walls made of a magnetic material.
The × B type mass separator has a function of separating ions having a desired mass from neutral particles and a function of removing neutral particles.

[0012]

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing the structure of an E × B type mass separator.
In the following description, the same symbols as those in FIGS. 4 and 5 indicate the same parts. The vacuum chamber 21 that serves as a beam passage in the E × B type mass separator 2 has a facing wall 21 made of a magnetic material.
₁ and a facing wall 21 ₂ made of a non-magnetic material. An exciting coil 22 as a magnetomotive force source is provided on the opposing wall 21 ₁ made of a magnetic material.
Is connected to the magnetic path 23, and the opposing wall functions as a magnetic pole that forms a uniform magnetic field in the chamber 21 by energizing the exciting coil. Opposing wall 21 made of non-magnetic material
_2, the opposing wall 21 ₁ of the magnetic steel is coupled through an insulator 26, the opposed walls, by applying a DC voltage, in parallel to form an electric field perpendicular to the magnetic field in the chamber 21 electrodes Work as.

With this configuration, it is not necessary to insulate the vacuum chamber 21 and to provide the parallel plate electrodes, and it is possible to secure a beam passage of a sufficient size. Further, since the opposing wall 21 ₂ of the outer surface of the non-magnetic material is located in the air unit, in the opposite wall, without providing a feedthrough terminal having a vacuum sealing function, directly from the atmosphere unit, applying a DC voltage You can

FIG. 2 is a cross-sectional view of another embodiment, and the same reference numerals as those in FIG. 1 denote the same parts. This E × B type mass separator 2
Is the same as the one shown in FIG.
7, the opposing walls 21 ₁ made of magnetic material are electrically insulated from each other.

By applying a DC voltage to the electrically insulated opposing walls 21 ₂ made of a magnetic material, an electric field is formed between the opposing walls. Ions having a desired mass introduced into the vacuum chamber 21 generate a magnetic field formed between the opposing walls 21 ₁ made of a magnetic material, and the opposing wall 2 made of a non-magnetic material orthogonal to the magnetic field.
An electric field formed between 1 and ₂ advances straight in the chamber, but an ion of a desired mass is deflected in the direction of the electric field due to the electric field formed between the opposing walls 21 ₁ made of a magnetic material and orthogonal to this electric field, and is bent. To be Therefore, it is possible to separate ions of a desired mass and neutral particles that are introduced into the vacuum chamber together with the same ions and are not affected by the electromagnetic field and go straight as they are, and have a neutral particle removal function. Become.

By using the E × B type mass separator 2 as described above, the ion irradiation apparatus does not require an electrostatic deflector for removing neutral particles, and is constructed as shown in FIG. can do. The analysis slit 3 is provided so that only the deflected ions having a desired mass pass through the slit, and neutral particles traveling straight through the mass separator 2 are shielded and removed by the analysis slit 3.

[0017]

Since the present invention is configured as described above, the vacuum chamber having a rectangular cross-section serving as a beam passage is composed of a magnetic material opposing wall and a non-magnetic material opposing wall.
In addition to having the opposing walls made of magnetic material function as magnetic poles for forming a magnetic field, the opposing walls made of non-magnetic material also function as electrodes for forming an electric field, so parallel plate electrodes are provided separately from the chamber. In addition, a DC voltage for forming an electric field can be directly applied from the atmosphere to the opposing wall made of a non-magnetic material, which eliminates the need to provide feedthrough terminals in the vacuum chamber. It is possible to simplify the mass separation mechanism of the chamber and the electromagnetic field forming unit and to downsize the entire mass separator while forming a beam passage of a sufficiently large size.

Further, by applying a DC voltage to the opposing walls made of a magnetic material and forming an electric field between the walls, only the ions having the desired mass to be introduced and the neutral particles are magnetized. It can be deflected in the direction of the electric field between the opposed body walls, separating the desired mass of ions and neutral particles and allowing the neutral particles to be removed.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of another embodiment.

3 is a configuration diagram of an ion irradiation apparatus using the E × B type mass separator shown in FIG.

FIG. 4 is a configuration diagram of an ion irradiation apparatus using an E × B type mass separator.

FIG. 5 is a sectional view showing an example of an E × B type mass separator.

[Explanation of symbols]

1 Ion source 2 E × B type mass separator 3 Analysis slit 4 Electrostatic deflector 5 Target 21 Vacuum chamber 21 ₁ Opposing wall made of magnetic material 21 ₂ Opposing wall made of non-magnetic material 22 Excitation coil 23 Magnetic path 26,27 Insulator

Claims (2)

[Claims] 1. An E × B type mass separator having a vacuum chamber having a rectangular cross section which serves as a beam passage, and an opposing wall made of a magnetic material, which is coupled to a magnetic path having a magnetomotive force source, and the opposing wall. An E × B mass separator, characterized in that it comprises the vacuum chamber which is electrically insulated and coupled, and comprises a non-magnetic opposed wall to which a DC voltage is applied. 2. An E × B type mass separator having a vacuum chamber having a rectangular cross section which serves as a beam passage, and is electrically connected to a magnetic path having a magnetomotive force source by an insulator provided in the magnetic path. And a non-magnetic opposing wall that is electrically insulated from the opposing wall and is electrically insulated from the opposing wall and is applied with a DC voltage. E × characterized by comprising
B type mass separator.