JPS5929290B2 - Dissolution method - Google Patents

Description

Detailed Description of the Invention This invention purifies the dissolved substance by injecting the ionized and accelerated substance into the dissolved substance and using the kinetic energy of the ionized and accelerated substance. Regarding the solvency power method.

Normally, the method of dissolving a substance involves heating the substance to be dissolved to the melting temperature or higher in a high vacuum or low gas pressure region to melt the substance, venting the occluded gas and releasing impurities. A vacuum melting method is used to obtain highly pure substances.

In addition, for example, an inert gas such as Ar may be introduced to control the amount of evaporation of the substance to be dissolved, or a reducing gas such as N2 may be introduced to remove oxides, or conversely, 0
Gas introduction methods that utilize the characteristics of gases are used, such as introducing reactive gases such as □ and N2 to generate oxides, nitrides, and the like.

These methods are mainly based on the use of thermal energy, but when looking at this thermal energy from the perspective of kinetic energy, it is kT/ekiT/1.16
As is clear from equation 10', even if the temperature T of the melting crucible for the substance to be melted is 2300°, the temperature T of the substance to be melted is 0.
The voltage is only 2eV, and 0.2V is applied to ions with charge e.
This is only the energy equivalent to applying an accelerating voltage of .

Note that k is Boltzmann's constant.

On the other hand, when implanting ions into a solid surface, several tens of K
Even ions with a kinetic energy of ev~several 100 KeV can reach only a few micrometers of the solid surface layer, and can only be used to treat the solid surface.

This invention takes the above points into consideration, and by injecting an ionized and accelerated substance into a melted substance, the present invention generates energy of several 100 V to several 10 KV, compared to the conventional case of using heat energy) When an accelerating voltage is applied, kinetic energy equivalent to a temperature of several million to hundreds of millions of degrees is imparted to the melted substance using the above-mentioned melting method using thermal energy, which is only possible at high temperatures, which is impossible to achieve. Reactions that would otherwise be impossible can be carried out under feasible conditions.

Furthermore, compared to ion implantation, since ionized substances are injected into dissolved and liquefied substances, not only does the depth of the implanted layer become deeper, but also the liquefied substances flow.
New surfaces of material are continually exposed on the crucible surface and injected one after another, and all the material to be melted and processed is processed by high-speed particles with kinetic energy.

Moreover, from a mechanical point of view, the injection of ionized and accelerated material into the surface of a dissolved material produces a pressurizing effect from the surface of the liquid phase, similar to that when attempting to pressurize mechanically. In addition, there is no need to heat the tool to a temperature higher than the temperature of the solution, and electrical pressure can be applied without contact, and the crystal composition of the dissolved substance can be greatly influenced by pressure condensation.

Next, the solving power method of the present invention will be explained in detail with reference to drawings showing examples thereof.

First of all, Figure 1 shows a relatively high-grade melting method.
d, metals such as Zn, magnetic materials such as Gd and Co, Si
The substance 1 to be dissolved, such as semiconductor materials such as Ge, other insulating materials, and organic materials, is placed in a high vacuum (10-10~
In the case of a metal or magnetic material, it is radio-frequency heated by a high-frequency coil 4 to which power from a high-frequency power supply 3 is introduced so that it becomes liquid in the crucible 2 at a temperature of 10-' Torr.

When the substance 1 to be melted is a semiconductor material, an insulating material, or an organic material, the crucible 2 may be heated by applying low voltage and large current directly to the crucible 2, or by emitting electrons to the outside of the crucible 2. A positive high voltage may be applied to the crucible 2.

It goes without saying that these heating means can also be applied to metals or magnetic materials.

- The required ions are generated by the ion source 5 provided in the same high vacuum container as the crucible 2.

That is, a vaporization chamber 8 communicating with an ion generation chamber 7 formed by an ion generation envelope 6 is loaded with a substance 9 to be ionized, which is the same type or different from the substance 1 to be dissolved, and the vaporization chamber 8 A heater 1 provided on the outer periphery of
0, the vaporization chamber 8 is heated, and the temperature of the vaporization chamber 8 is adjusted by the thermocouple 11 inserted into a part of the vaporization chamber 8, and the substance 9 to be ionized is heated to a vapor pressure of 10-3 to 10-3.
The ion generation chamber 7 is vaporized to about 10”-ITorr.
sent to.

The illustrated ion source 5 is an example using a type normally called a cold cathode PIG type ion source, in which a discharge anode 12 is provided in the ion generation chamber 7, and a protruding part is provided on a part of the envelope 6. A cold cathode 13 is formed, a discharge voltage Vd is applied between the discharge anode 12 and the cold cathode 13, and the vaporized substance 9 is ionized.

Furthermore, a magnet 14 is provided on the outside of the envelope 6,
A spiral motion is given to the electrons in the ion generation chamber 7 to improve ionization efficiency.

Note that instead of the cold cathode 13, a hot cathode filament independent from the envelope 6 may be provided.

The substance 9 ionized in the ion generation chamber 7 is
The ions are extracted from an ion extraction hole 15 formed in a part of the envelope 6, and accelerated by an ion extraction electrode 16 provided outside the ion extraction hole 15 and to which an ion acceleration voltage Va is applied.

Further, an ion beam forming focusing system 17 to which an appropriate voltage is applied is provided outside the ion extraction electrode 16,
Ions are focused by this focusing system 17 to form an ion beam 18, which is sent to a mass separator 19.

An ion beam slit 20 is appropriately provided at the entrance of the mass separator 19 to maintain the size of the ion beam 18 appropriately.

And, by the magnet that constitutes the mass separator 19,
A magnetic field is applied perpendicular to the direction of motion of the ion beam 18 to deflect the ion beam 18 as shown.

In this case, since the deflection sensitivity of the ion beam 18 differs depending on the substance constituting the ions, the magnetic field generated by the mass separator 19 is appropriately adjusted to purely extract and analyze only the necessary ions.

The ion beam 18 analyzed by the mass separator 19 is then projected onto the surface of the liquid substance 1 in the crucible 2 .

As a result, as described above, the kinetic energy of the ion beam 18 produces the same effect as mechanical pressure, which affects the crystal structure of the substance 1 or controls the crystal composition by the ion implantation effect, and at the same time Since the surface of the substance 1 is constantly flowing, the effect can be uniformly applied to the entire substance 1.

Note that during the above operation, it is also possible to introduce various gaseous substances continuously or alternately in a high vacuum region to chemically activate and promote chemical reactions.

For example, when making a transition metal silicide among intermetallic compounds, a typical example is Fe.

The case of synthesis of Si will be explained.

Fe is loaded into the crucible 2 and melted, and Si is loaded into the vaporization chamber 8 communicating with the ion generation chamber 7, vaporized and ionized, and accelerated with an ion acceleration voltage of 5 to 10 KV applied to the ion extraction electrode 16. , a focusing system 17, and a mass separator 19, and then impinge on the surface of the liquid Fe material 1 in the crucible 2 as a Si ion beam 18.

Generally, when synthesizing two or more substances, those component substances are melted in the same crucible, and only those with a specific composition determined from a phase diagram can be synthesized.

By the way, in the case of Fe and Si, it is Fe5i (ε type).

F es i2 (I'm) can maintain stoichiometric equilibrium.

However, according to the method of the present invention, the thermal equilibrium state can be removed with the help of kinetic energy, so the stoichiometric equilibrium state can be changed.

Furthermore, as mentioned above, since it is possible to simultaneously introduce reactive gases such as 02 or N2, Fe, S
In the case of i, it is also possible to introduce an oxygen atmosphere of about 10 -4 to 1 O -2 Torr to create an impurity level of 0□ in Fe and Si.

Furthermore, ε-type FeSi prepared by the conventional melting method has a Seebeck coefficient α of 40 μV/deg, whereas the value obtained by the method of the present invention is , it becomes 10 MV/deg, and a high conversion efficiency that could not be obtained conventionally can be obtained.

Furthermore, with conventional melting methods, synthetic materials exhibit polycrystalline properties, making it difficult to form them into an amorphous structure.

However, according to the method of this invention, it can be carried out very close to the melting point of Fe and rapid cooling is possible, so F
eSi can be made and high conversion efficiency as described above can be obtained.

Next, the case of GdCo2 as the magnetic material will be explained.

Generally, a magnetic material is made by melting Gd and Co in a single crucible, but in that case, only a polycrystalline structure can be produced.

Also, the melting point of Gd is 1312°C, and the melting point of Co is 1495°C.
.degree. C., the temperature must be at least 1495.degree. C. or higher, which makes rapid cooling difficult and requires a complicated device to maintain the high temperature.

However, according to the method of this invention, Gd with a low melting point can be melted in a crucible, Co can be ionized, and the surface of Gd can be irradiated, so the temperature of the crucible does not necessarily need to be 1495°C or higher, and the temperature is relatively low. In addition, it is possible to produce an amorphous material whose composition deviates from the stoichiometric equilibrium state determined by the phase diagram.

As mentioned above, there is no need to heat component substances with high melting points, operating conditions can be obtained to suit component substances with low melting points, and rapid cooling is easy, so it is possible to obtain materials that previously only had a polycrystalline structure. A major feature of this invention is that it can be obtained as an amorphous structure.

Furthermore, this invention can be applied to combinations of various substances,
For example, in the case of TiZr, the melting point of Ti is 1680° C. as the standard while the melting point of Zr is 1860° C., and the range of application is wide.

Next, the present invention is also extremely advantageous in the synthesis of organic metals.

That is, generally, an organic substance has a low melting point, and a metal bonded thereto often has a high melting point.

In this case, it is possible to control the chemical composition and structure by liquefying the organic substance and ionizing the metal elements.

For example, dimethyl zinc (CH3)2 Z n %
Examples include F-limethylgallium (CH3)3Ga.

The explanation of FIG. 1 above is an advanced method of selecting ions very strictly when injecting ions into the surface of a liquid substance 1, but it is also possible to use a simple dissolving power method as shown in FIG. 2. You can also do it.

That is, in FIG. 2, the ion beam forming focusing system 1T and mass separator 19 shown in FIG. The electron beam 22 obtained from the electron beam 21 is directly irradiated onto the surface of the substance 1 to be melted in the crucible 2 to melt it.

The electric power of this electron beam 22 is applied to the substance 1 to be dissolved.
Although it depends on the type and amount of
A current of about several hundred mA is used.

Electric power, the ionization of the substance 9 to be ionized is also the first
Unlike the case shown in the figure, a substance 9 to be ionized is loaded into a closed crucible 23 and heated.

In the illustrated case, this heating is performed by forming power supply terminals 24.25 on the outer wall of the crucible 23 and flowing a low voltage of 5 to 10 Ω and a large current of several 10 OA between both terminals 24.25. In addition to this, an electron impact heating method, a high frequency heating method, or a combination heating method thereof may be used.

The substance 9 heated and vaporized in the crucible 23 is injected from one or more injection nozzles 26 formed in the crucible 23.

An ionizing electrode 30 consisting of an ionizing electron emitting filament 27, an electron accelerating anode 28, and a shielding electrode 29 is provided on the outside of the injection nozzle 26.
Kinetic energy is applied by 8, and a part or most of the vaporized substance 9 is ionized, becoming ionized substance vapor 32, and further accelerated by an accelerating electrode 33 or a shielding electrode 29.
Accelerated by the voltage applied to the liquid substance 1, the injected vapor, which is not ionized and remains neutral, is forced into the surface of the liquid substance 1.

In addition, in order to give acceleration energy to the electron beam 22 of the electron gun 21, a negative high voltage is applied to the accelerating electrode of the electron gun 21 with respect to the crucible 2, while the crucible 2 is placed on the side to be ionized and accelerated.
Since a positive high voltage must be applied to the electron gun 21 and the ionization electrode 30, a shielding partition 34
It is desirable to provide

The process shown in FIG. 2 is carried out in the envelope 35 indicated by the dashed line in the figure.Similar to the case shown in FIG. It may be introduced continuously or intermittently at an appropriate pressure.

Furthermore, in FIGS. 1 and 2, the substance that is ionized, accelerated, and injected into the dissolved substance is solid at room temperature, but it is of course possible to use a gaseous substance. .

Furthermore, although we have explained about so-called positive ions with a charge of 10, ionized substances have the same effect with negative ions of -0, and in this case, a high positive voltage is used as the ion acceleration voltage. Bye.

As described above, according to the dissolving power method of the present invention, by injecting an ionized and accelerated substance into a dissolved substance, the kinetic energy of the ionized and accelerated substance is used in conjunction with the ionized and accelerated substance. Control of crystal structure or composition or compound synthesis, which is difficult to obtain by dissolution methods, can be easily performed.

[Brief explanation of drawings]

The drawings show an embodiment of the melting method of the present invention, and FIG. 1 is an explanatory diagram of one embodiment, and FIG. 2 is an explanatory diagram of another embodiment. 1...Substance to be dissolved.

Claims (1)

[Claims] 1. In a vacuum or low gas pressure region, the substance to be dissolved is heated and melted using direct current or alternating current power, high frequency, electron beam irradiation, etc., and the dissolved substance is ionized and accelerated to contain the same or different substance as the substance. Solvent force method characterized by injecting a substance.