JPS60185338A - ion source - Google Patents

Abstract

PURPOSE:To use as an electric field ionization ion source as well as an electro- hydrodynamic ion source by constructing such that an anode will penetrate through the bottom of an insulative bottle to flow gas between the control electrode and the bottle. CONSTITUTION:An ion source is comprised of an anode 1 where a needle is welded to the end of a hairpin filament and fixed to the bottom of a silicon bottle 4, a control electrode 2 and a cathode 3. When using as an electro-hydrodynamic ion source, ionization substance 5 is adhered to the filament and heated through power supply, then the tip of said needle is dampened thereafter high voltage negative against the anode 1 is applied onto the cathode 3 to produce an ion beam 8, while when using as an electric field ionization source, ionization substance or gas is fed between the bottle 4 and the control electrode 2 to apply voltage thus to produce an ion beam 8. In such a manner, it can be used in two systems as required.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an ion source, and more particularly to an anode having a needle, a capillary, or a capillary needle attached to its end, and an anode provided opposite to the anode. The present invention relates to a high-intensity ion source comprising: a cathode with a J=ii2 anode; and a control electrode provided between the cathodes.

[Background of the invention]

High brightness ion sources include electrohydrodynamic (E), electro
-hydrodynamic) (hereinafter abbreviated as EHD in this specification) ion source and electric field ionization (
There is an ion source (hereinafter abbreviated as FI). The former is
While the element to be ionized is a low melting point metal element, the latter is a gas element. Emitting various ion species from the same ion source is very effective when considering the application of ion microbeam technology. For example, the present invention eliminates the need for readjustment of the optical system as in the prior art. Conventionally,
No ion source existed that could be operated as both an E HD ion source and an FT ion source.

Known examples of ionization using gas include J, H,
0rloff and L, W, Swanson
: “5tudy ofa field joniza
tion 5source for mjcroprob
eapplicat, jon”J, Vac, Sci, T
echnol,,Vow,]2゜No, 6. NOV
, /DAC,]975.

[Purpose of the invention]

The object of the invention is therefore to provide an ion source that can be operated both as a 1Σ)(I) ion source and as an FT ion source.

[Summary of the invention]

In order to achieve the above objective, the present invention provides an ion source of the kind mentioned at the outset, in which the anode is provided through the bottom of a bottle made of an insulating material into which a coolant can be placed. , an ion source characterized in that it can operate as both an electrohydrodynamic ion source and a field ionization ion source, in which a gas can flow between a control electrode and a cathode or between a bottle and a control electrode. .

[Embodiments of the invention]

The present invention will be described in more detail below using examples with reference to the accompanying drawings, but these are merely illustrative, and it goes without saying that various improvements and modifications may be made without going beyond the scope of the present invention. It is.

FIG. 1 is a cross-sectional view of an ion source according to the present invention.

The ion source consists of an anode 1, a control electrode 2, and a cathode 3, as shown. In this case, the anode 1 is of a needle type, and a needle having a tip with a curvature of several α nm or more in diameter is welded to a spora 1 at its terminal end to the hairpin-shaped filament 1. This anode is attached to the bottom of a bottle 4 made of an insulating material such as stone yellow.
The ionizable substance 5 for the ETTD mode is attached to the filament 1. In order to extract these ions, the temperature of the anode is increased by heating the filament with electricity, the ionized substance is melted and wetted to the tip of the needle, and then the potential of the cathode 3 is set to several kV or more negative with respect to the anode 1. When set to 1-, ion beam 8 is obtained.

On the other hand, in order to operate in the Fl mode, the anode temperature is kept below the melting point of the ionized substance to prevent future ion release. between the control electrode 2 and the cathode 3
Introduced from between.

When a potential of the same polarity as in EHD is applied between the anode 1 and the cathode 3, the gas is extracted as an elemental ion beam 8. In this mode, the gas partial pressure in the region between the bottle 4 and the cathode 3 must be about 40-'' Pa. Also, in this mode, in order to increase the ion current, A coolant 7 such as liquid nitrogen or liquid helium is placed inside the bottle 4 so that the anode temperature can be lowered to a minimum temperature of about 4.

In either mode, the control electrode is connected to the positive or negative 1. A potential of about kV or less is applied to control the ion current.

Using the ion source described above, in EHI) mode, when the extraction voltage is 4 to 10 kV, G a I A I
ITBj, etc. were extracted as an ion current of 1 to 10 μA. On the other hand, in FI Mol, liquid nitrogen was used as the coolant, and when the extraction voltage was 8-20 kV, an ion current of 10-3 to 10''μA of H, Ar, etc. was obtained. Tungsten was used for the needle at this time.

Although the above example uses a needle type anode, similar results have been obtained with a capillary type and a capillary needle type.

〔Effect of the invention〕

According to the present invention, one ion source can be used as an EHD as needed.
It can be used in either mode or FT mode.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an ion source according to the present invention. 1... Anode 2... Control electrode 3... Cathode 4... Bottle 5... Ionized substance 6... Gas 7 - Coolant 8... Ion beam agent patent attorney
Junnosuke Nakamura Figure 1 2 “Viscous IT-, -1r-3 -μF (method)%
Formula % [1 1, Indication of the case Patent Application No. 2314 of 1982] / No. 1 2, Title of the invention Ion source 3, Relationship with the person making the amendment Patent applicant name (51,0) Co., Ltd. Ne1 :11 Ritsu Seisakusho 4, Agent 6, Subject of amendment Column 7 for detailed explanation of the invention in the specification, Contents of the amendment Attachment (As shown in Appendix J Contents of the amendment (1) From line 19 of page 2 of the specification Page 3, line 2, J, H, -- Nov./Dec., 1975, J. H. Owluff and L. D. Swanson: “Study of Afield Ionization Sources for Microprobe Applications” J. . Vacuum, Society, Technology 1. Volume,
12. No. 6, November/December 1
975 (J, H, Orl, off and L,
W. Swanson: “5tudy of a
field 1onjzation 5source
formjcroprobeappljcation
” J, Vac, Scj. Technol, Vow, 12. No.
6, Nov./Dec. 1975).

Claims (1)

[Claims] An ion source comprising: an anode having a needle, capillary, or capillary needle attached to its end; a cathode opposite the anode; and a control electrode between the anode and the cathode. , the anode is provided through the bottom of a bottle made of an insulating material capable of containing a coolant, and the gas is allowed to flow between the control electrode and the cathode or between the bottle and the control electrode. An ion source characterized in that it is capable of operating both as an electrohydrodynamic ion source and as a field ionization ion source.