JPH0917367A - Ion source device - Google Patents

Abstract

PURPOSE: To eliminate instability of an ion beam extraction characteristic by failure of a using electrode by lengthening the service life by improving oxidation resistance or corrosion resistance of extraction electrodes. CONSTITUTION: An ion source device extracts an ion beam 18 from plasma 17 generated in a plasma generating vessel 1 by using one or more extraction electrodes 15. In this ion source device, at least the most plasma side electrode 6 of the electrodes 15 is covered with a film 16 composed of at least one kind among gold, silver and platinum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion source device for extracting an ion beam from plasma generated in a plasma generating chamber by using one or more extraction electrodes.

[0002]

2. Description of the Related Art A conventional ion source device of this type introduces a gas or an ionized substance such as a vaporized metal into a plasma generating container to form a plasma generating container also serving as an anode and an electron emission source such as a filament. Arcing between
Plasma is generated, and an ion beam is extracted from the plasma by the action of an electric field by a porous extraction electrode.

As a material for the electrode, a refractory metal such as molybdenum or tungsten is used because it is exposed to high-density plasma when the ion beam is extracted.

[0004]

In the case of the above-mentioned conventional apparatus, when plasma is generated using a gas containing oxygen or a halogen element as a raw material, the material of the extraction electrode is oxidized or corroded, and the life is shortened. In addition, there is a problem that the ion beam extraction characteristics become unstable due to defective electrodes during use.

In the present invention, in consideration of the above points, the oxidation resistance or the corrosion resistance of the extraction electrode is improved to prolong the life,
It is an object of the present invention to provide an ion source device capable of eliminating the instability of the characteristics of extracting an ion beam due to a defective electrode in use.

[0006]

In order to solve the above-mentioned problems, the ion source device of the present invention is such that at least one electrode of at least one of the extraction electrodes on the most plasma side is at least one of gold, silver and platinum. It is coated with a film consisting of.

[0007]

In the ion source device of the present invention configured as described above, at least the electrode on the most plasma side of the extraction electrode is made of gold,
Since it is coated with a film composed of at least one of silver and platinum, an electrode with good oxidation resistance or corrosion resistance is constructed,
Even when plasma is generated by using an oxidizing or corrosive gas containing oxygen or halogen element as a raw material, the life of the electrode can be extended and the instability of the ion beam extraction characteristics due to the defect of the electrode during use can be eliminated. It

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment, for example, a bucket type ion source device will be described with reference to FIGS. 1 is a cut-away front view, and FIG. 2 is a front view of a part of the electrode of FIG. 1, in which 1 is a plasma generation container in which a plasma chamber 2 is formed, and 3 is an upper opening of the container 1. Lid plate,
Reference numeral 4 denotes a flange whose upper surface is attached to the lower surface of the container 1 via an insulator 5, and 6 denotes a porous plasma electrode on the most plasma side as an acceleration electrode to which a positive voltage is applied.
The plasma electrode 6 is supported on the flange 4 by being mounted on the upper surface of the supporting portion projecting inwardly of the via the insulator 7. Reference numeral 8 denotes a cooling pipe provided on the plasma electrode 6, both ends of which penetrate the flange 4 and are supported by the flange 4 to alleviate thermal strain of the plasma electrode 6.

Reference numeral 9 denotes a flange mounted on the lower surface of the flange 4 via an insulator 10, and reference numeral 11 denotes a porous type suppression electrode having a diameter smaller than that of the plasma electrode 6 to which a negative voltage is applied. It is located and is supported by the flange 9 via a support member (not shown). Reference numeral 12 denotes a cooling pipe which is provided on the suppression electrode 11 and whose both ends are supported by the flange 9. Reference numeral 13 denotes a porous suppression electrode 1 which is grounded.
The ground electrode has a diameter smaller than that of 1, and is located below the suppression electrode 11 and is supported by the flange 9 via a support member (not shown). Reference numeral 14 is a cooling pipe which is provided on the ground electrode 13 and whose both ends are supported by the flange 9.

Reference numeral 15 is an extraction electrode composed of the plasma electrode 6, the suppression electrode 11 and the ground electrode 13, and is located at the lower opening of the container 1 facing the lid plate 3. Reference numeral 16 is a film made of at least one of gold, silver and platinum, which is at least the electrode on the most plasma side of the extraction electrodes 15, that is, the plasma electrode 6 by the PVD method such as electrolytic plating, thermal spraying, vacuum deposition or sputtering. Is covered with.

Then, an oxidizing or corrosive gas containing oxygen or a halogen element is introduced into the plasma chamber 2 of the container 1,
When electrons are emitted by an electron emission source (not shown) above the container 1, for example, a filament, and the container 1 is set to an anode potential and the filament is set to a cathode potential, a plasma 17 is generated by arc discharge, and the plasma 17 is generated. The ion gas in the plasma 17 is extracted by the extraction electrode 15 and is densified by a cusp magnetic field formed by a permanent magnet (not shown) provided on the outside of the container 1, as shown by the arrow in FIG. Thus, the ion beam 18 is extracted.

At this time, since at least the plasma electrode 6 of the extraction electrode 15 is covered with the film 16, the plasma electrode 6 is not oxidized or corroded, and the ion beam extraction characteristics are stable.

It goes without saying that the suppression electrode 11 and the ground electrode 13 may be covered with the film 16.

The materials for the electrodes 6, 11 and 13 are metals such as molybdenum, tungsten, tantalum, stainless steel, copper, carbon, silicon carbide, titanium boride, and the like.
It may be selected from conductive ceramics such as chromium boride and zirconium boride.

Further, the material of the cooling pipes 8, 12, 14 may be selected from metals such as molybdenum, tungsten, tantalum, stainless steel and copper, and the cooling pipes 8, 12, 14 are also covered with the film 16. Preferably.

The present invention can also be applied to an extraction electrode without a cooling pipe.

[0017]

Since the present invention is constructed as described above, it has the following effects.

The ion source device of the present invention comprises an extraction electrode 15
Since at least the electrode 6 on the most plasma side is covered with the film 16 made of at least one of gold, silver and platinum, the electrode 6 having good oxidation resistance or corrosion resistance can be formed, and the electrode 6 containing oxygen or halogen element is included. Even when the plasma 17 is generated by using an oxidizing or corrosive gas as a raw material, it is possible to extend the life of the electrode 6 and eliminate the instability of the ion beam extraction characteristics due to the defect of the electrode 6 during use. You can

[Brief description of the drawings]

FIG. 1 is a cutaway front view of one embodiment of the present invention.

2 is a front view of a portion of the electrode of FIG.

[Explanation of symbols]

 1 Plasma Generation Container 6 Electrode 15 Extraction Electrode 16 Film 17 Plasma 18 Ion Beam

Claims (1)

[Claims] 1. An ion source device having a structure for extracting an ion beam from plasma generated in a plasma generation chamber by using one or more extraction electrodes, wherein at least the electrode on the most plasma side of the electrode is made of gold, silver, or An ion source device characterized by being coated with a film made of at least one of platinum.