JPS5852295B2 - metal ion source - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal ion source that generates metal ions used in ion accelerators and the like.

FIG. 1 is a longitudinal sectional view showing a conventional metal ion source.

In the figure, 1 is a container body, 2 is a cathode, 3 is an anode, 4 is a solenoid for plasma excitation, 5 is an inlet for gas that becomes plasma, 6 is an opening for drawing out metal ions in the plasma,
7 is a terminal for supplying power to the anode 3; 8 is a container for evaporating metal; 9 is metal grains for emitting the desired ion species; 10 is for heating the metal grains to release the metal particles. This is a heater for evaporation.

Next, the operation of the metal ion source with the above configuration will be explained.

First, the heater 10 is heated to heat the metal particles 9 in the container 8 to a high temperature to generate metal vapor.

Then, when a high voltage is applied between the cathode 2 and the anode 3 and the plasma excitation solenoid 4 is driven to introduce gas to become plasma from the inlet 5, plasma is generated between the cathode 2 and the anode 3.

When the generated metal vapor is introduced into the plasma excited region composed of the cathode 2 and the anode 3, the metal vapor is ionized by the plasma, and the metal ions are released outward from the ion extraction port 6. is released.

However, because it requires a two-step process of generating metal vapor and ionizing the generated metal vapor, the structure is more complex and the entire device becomes larger than an ion source using a substance that is a gas at room temperature. do.

That is, the temperature is usually between 500°C and 20°C for the generation of metal vapor.
Since the extremely high temperature of 00°C is required, an evaporation container made of a substance with a high melting point is required, and a heater that efficiently generates extremely high temperatures, a power source for the heater, and a temperature measurement inside the evaporation container are required. However, it requires a thermometer for adjustment, a temperature controller, a heat insulator and a cooling device (not shown) to protect peripheral equipment from the high temperature of the hexagram and evaporation vessel.

Furthermore, when gaseous ions are required, it is necessary to break the vacuum and replace the ion source, which is extremely troublesome.

Therefore, an object of the present invention is to provide a metal ion source that does not require any equipment for generating metal vapor, has a simple structure, and can be made compact.

In order to achieve such an object, the present invention is such that at least one of the cathode and anode is made of or contains a metal that releases the desired metal ions. This will be explained in detail using .

FIG. 2 is a longitudinal sectional view showing an embodiment of the metal ion source according to the present invention.

In the figure, reference numeral 11 denotes a cathode capable of releasing a target metal ion, and may be made of, for example, a metal capable of releasing the metal ion, or may be made of a material containing the metal.

Next, the operation of the metal ion source with the above configuration will be explained.

First, between the cathode 11 and the anode 3, for example, IKV to 3K
When a high voltage of V is applied and the plasma excitation solenoid 4 is energized, four magnetic fields parallel to the cylinder axis are generated.

When an inert gas having a relatively large mass, such as argon or xenon, is introduced from the gas inlet 5, an inert gas plasma is generated under high voltage and a magnetic field.

The inert gas ions generated in this plasma are transferred to the anode 3.
Accelerated by the high voltage between the button and the pole 11, the cathode 11
of.

Collision with a surface.

Therefore, metal atoms on the surface of the cathode 11 are sputtered by inert gas ions, eject into the plasma, and are ionized there.

Then, some of the ionized inert gas ions and metal atom ions are extracted from the opening 6.

In addition, although the cathode 11 is configured so as to be able to emit the intended metal ions, it goes without saying that the anode or both the anode and the cathode may be configured in the same manner.

As explained above in detail, the metal ions according to the present invention do not require a set of evaporators that generate metal vapor,
The simple structure allows metal ions to be easily generated.

Furthermore, since it can be used for gas, it is extremely easy to switch from metal ions to gas ions or vice versa, and it has great economic advantages such as shortening work time.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a conventional metal ion source, and FIG. 2 is a longitudinal sectional view showing an embodiment of the metal ion source according to the present invention. 1... vessel body, 2... cathode, 3...
...anode, 4... solenoid for plasma excitation,
5...Inlet, 6...Opening, 7...
...one terminal, 8...container, 9...metal particles, 10...heater, 11...pak pole Note that the same 〇 symbol indicates the same or A considerable portion is shown.

Claims (1)

[Claims] 1 A container provided with an inlet for introducing gas to become plasma at one end and an opening for drawing out metal ions in the plasma at the other end, a cathode and an anode arranged facing each other inside this container, and the above-mentioned container. In a metal ion source equipped with a solenoid for plasma excitation provided on the outer periphery of the body, at least one of the cathode and the anode is made of or contains a metal capable of emitting the intended metal ions. Characteristic metal ion source.