JPH02815B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to the improvement of a needle-type liquid metal ion source, which is a high-intensity ion source necessary for generating ion microbeams, and particularly relates to the improvement of a needle-type liquid metal ion source, which is a high-intensity ion source necessary for generating ion microbeams. This relates to longer life and higher performance in power sources.

[Background of the invention]

Conventional means for replenishing ionized substances in needle-type liquid metal ion sources can be broadly classified into two types.

One ion source has a storage section for ionized material directly above the needle support section, from which the needle is supplied in liquid form. Although this configuration is excellent in terms of longevity, it has the following problems. Because the needle and reservoir are not sufficiently insulated, it is necessary to heat not only the needle but also the reservoir during operation of the ion source.
Heating the reservoir requires more power as the melting point of the ionized substance increases, and since this is not directly related to ionization, it becomes less efficient in terms of energy. Furthermore, if the surface of the reservoir is heated to a high temperature of several hundred degrees or higher, contaminating elements such as alkali metals are ionized and released through the surface ionization process. This is often inconvenient because the target ion species tends to be mixed in as impurity ions.

Another ion source utilizes the V-shaped corner of a hairpin as a source of ionized material. In order to store a large amount of
As shown in Japanese Patent No. 114257, this corner may be bridged with a metal wire, or it may be wrapped in a spiral shape. Although this configuration has a simple structure and requires less electric power to heat the anode, it has the disadvantage that a large amount of ionized material cannot be deposited.

[Purpose of the invention]

The present invention solves the above-mentioned drawbacks, namely, when the ion source is operated, only the anode is heated and other parts are not heated to high temperatures, and the liquid metal ion source can store a large amount of ionized substance and extend its life. The purpose is to provide a source of information.

[Summary of the invention]

Therefore, in the present invention, the space between the anode and the ionized substance storage section is insulated, and the ionized substance is supplied from the ionized substance storage section to the anode by heating the storage section to evaporate the ionized substance when necessary. The liquid metal ion source is configured to perform this by blowing vapor onto the anode and condensing it.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 1 shows the basic configuration of a liquid metal ion source according to the present invention. In the vicinity of the anode 1 there is a reservoir 2 for ionized material 4, which is equipped with a nozzle 3. The reservoir 2 can be heated by a heater 5, and the vapor 6 of the ionized substance 4 is emitted from the noise 3 and blown onto the anode 1. This improved heating of only the anode 1 during operation of the ion source.

When the ionized substance 4 is gold, the melting point is 1063℃, and the temperature of the anode 1 is 1100-1300℃ during operation.
Keep it. At this time, when a positive potential of several KV or more is applied to the anode 1, gold ions of about 10 μA are obtained from the needle tip of the anode 1. When gold is placed on anode 1 in a spherical volume with a diameter of less than 1 mm,
The lifetime of a stable ion beam is about 100 hours. Therefore, when the beam became unstable, the ionized material storage section 2 was heated and the ionized material was newly supplied to the anode 1. By doing this, we were able to extend the lifespan. Naturally, its value is proportional to the amount of ionized substance 4 put into reservoir 2.

In the above example, there is one nozzle 3 from the reservoir 2 and it is installed in one direction of the anode 1, but a plurality of nozzles 3 may be provided and arranged around the anode 1.

Furthermore, a configuration may be adopted in which a plurality of ionized substance storage units are prepared and ions of a plurality of elements are generated in time series.

〔Effect of the invention〕

As described above, the present invention has made it possible to provide a liquid metal ion source that is power efficient and has a long life.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of a liquid metal ion source according to the present invention. 1...Anode, 2...Part for ionized substance, 3
...Nozzle, 4...Ionized substance, 5...Heater, 6
...gas vapor of ionized substances.

Claims (1)

[Claims] 1. In a liquid metal ion source that wets the tip of a needle with a molten metal substance to be ionized and extracts ions from the tip using a strong electric field, the ionized substance contained in the reservoir is heated to form a vapor, and the vapor is A liquid metal ion source characterized in that the ionized substance is supplied by colliding with the needle or a support portion of the needle and condensing it.