JP2023154377A - Vaporizer, ion source equipped with the same, and method for manufacturing aluminum-containing vapor - Google Patents

Abstract

To provide a new vaporizer capable of solving the problem of insulation of an extraction electrode without using hydrogen gas.SOLUTION: A vaporizer 1 includes a crucible 2 in which an aluminum-containing solid material 7 is placed, and a heater 5 that heats the crucible 2, and the crucible 2 includes a chlorine-containing gas inlet 2b that introduces chlorine-containing gas into the crucible 2, and a steam release port 2a that releases aluminum-containing steam generated by heating the reaction product of the chlorine-containing gas and the solid material 7 to the outside of the crucible 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vaporizer, an ion source including the vaporizer, and a method for producing aluminum-containing vapor.

Silicon carbide (SiC) devices are expected to be used in high-voltage, high-temperature applications such as electric vehicles, railways, and power plants. Something similar to a silicon device is used.

In the ion implantation process for SiC devices, nitrogen ions and phosphorus ions are implanted as N-type dopants, and aluminum ions and boron ions are implanted as P-type dopants into a SiC wafer to produce a PN junction.

Nitrogen ions, phosphorus ions, and boron ions are generated by turning raw material gas into plasma.
On the other hand, when generating aluminum ions, there is no optimal gas as a raw material, and solid materials containing aluminum and auxiliary gases such as fluorine-containing gases are used.

Patent Document 1 discloses a method for generating an ion beam containing aluminum ions using an aluminum-containing solid material.
An aluminum-containing solid material is placed in the plasma generation chamber of the ion source. Next, a corrosive gas containing a fluorine component such as phosphorus trifluoride, phosphorus pentafluoride, or boron trifluoride is supplied to the plasma generation chamber to generate plasma containing fluorine ions and fluorine radicals.

The aluminum-containing solid material is supported by a reflective electrode to which a negative voltage is applied. Fluorine ions in the plasma are attracted to the reflective electrode on which the aluminum-containing solid material is supported and physically sputter the aluminum-containing solid material.
On the other hand, fluorine radicals in the plasma chemically react with the aluminum-containing solid material to chemically sputter the aluminum-containing solid material.
Aluminum particles are released from aluminum-containing solid materials by physical or chemical sputtering.

Aluminum particles emitted from the solid material collide with high-energy electrons emitted from the cathode within the plasma generation chamber and are ionized. As a result, aluminum ions are generated in the plasma derived from the corrosive gas.
An ion extraction port for extracting the ion beam is formed on one surface of the plasma generation chamber. An ion beam containing aluminum ions is extracted from the plasma in the plasma generation chamber through an ion extraction port by an extraction electrode disposed adjacent to the plasma generation chamber.
The extracted ion beam is subjected to mass analysis along the ion beam transport path, and then irradiated onto the SiC wafer, thereby implanting aluminum ions into the SiC wafer.

JP2011-124059 JP2014-502409

During operation of the ion source, aluminum fluoride (AlF ₃ ), which is a reaction product between fluorine and aluminum, and reaction products between fluorine and high melting point materials (tungsten and molybdenum) that make up the extraction electrode are deposited on the extraction electrode surface. .
These deposits are insulators. Over time, the surface of the extraction electrode is covered with deposits and the extraction electrode becomes insulated.
If the extraction electrode is insulated, it becomes impossible to extract the desired ion beam, so the operation of the ion source is temporarily stopped to clean the deposits on the extraction electrode.

However, when cleaning the extraction electrode, a problem arises in that the operating rate of the ion source decreases. Therefore, in order to improve the operating rate of the ion source while solving the problem of electrode insulation, a method using hydrogen gas disclosed in Patent Document 2 has been proposed. In this method, hydrogen fluoride (gas) is generated by introducing hydrogen gas into the plasma generation chamber during operation of the ion source and reacting with the fluorine component that causes electrode insulation. Finally, the generated hydrogen fluoride is exhausted to the outside of the device using a vacuum pump. By using this method, the amount of deposits deposited on the extraction electrode is reduced, so the period until the extraction electrode needs to be cleaned is lengthened, and the operating rate of the ion source is improved.
However, since the method of Patent Document 2 requires a large amount of hydrogen gas, there are problems such as the need for gas supply piping for hydrogen gas and the complexity of gas management due to an increase in the types of gas to be managed. becomes.

Therefore, we have developed a new vaporizer and an ion source equipped with this vaporizer that can solve the problem of insulating the extraction electrode and improve the operating rate of the ion source without using hydrogen gas, as well as Provide a generation method.

The vaporizer is
a crucible in which an aluminum-containing solid material is placed;
and a heater that heats the crucible,
The crucible includes a chlorine-containing gas inlet for introducing a chlorine-containing gas into the crucible;
The crucible has a steam discharge port for discharging aluminum-containing steam generated by heating the reaction product of the chlorine-containing gas and the solid material to the outside of the crucible.

In order to vaporize the aluminum-containing solid material itself, it is necessary to heat the solid material to a high temperature, but in the case of aluminum chloride, which is a reaction product with chlorine, the temperature to vaporize it is low. This facilitates the production of aluminum-containing vapor.
The vaporization temperature of aluminum chloride is lower than the surface temperature of the extraction electrode during ion source operation, so even if aluminum-containing vapor, mainly aluminum chloride, adheres to the extraction electrode, it will not be deposited on the extraction electrode. Evaporate. As a result, the problem of insulating the extraction electrode does not occur, and the operating rate of the ion source is improved to a great extent.
Further, since there is no problem with insulation of the extraction electrode, hydrogen gas is not required, and various problems that have occurred with the use of hydrogen gas are also solved.

To increase the proportion of aluminum in aluminum vapor,
Preferably, the solid material is pure aluminum.

Pure aluminum has a high boiling point, and in order to generate steam from pure aluminum, it is necessary to raise the temperature of pure aluminum to about 2500° C. under atmospheric pressure, which requires a high-output heater.
However, the vaporization temperature of aluminum chloride, which is a reaction product with a chlorine-containing gas, is as low as about 180° C., so a high-output heater is not required.

In order to uniformize the plasma density within the plasma generation chamber by supplying steam in a distributed manner,
Preferably, the steam outlet emits the aluminum-containing steam in multiple directions.

The configuration of the ion source is
The above vaporizer;
It has a plasma generation chamber that generates plasma inside,
Preferably, the ion source emits the aluminum-containing vapor into the plasma generation chamber through a wall surface of the plasma generation chamber.

When considering ionic species contamination,
The plasma generation chamber has a first gas inlet and a second gas inlet,
The aluminum-containing vapor is supplied to the first gas inlet through the vaporizer,
It is desirable that a gas made of a component other than aluminum is supplied to the second gas inlet.

In order to equalize the crucible temperature,
The crucible is
a first end including the chlorine-containing gas inlet, a second end including the steam discharge port, and a main body between the first end and the second end in a first direction. ,
In the first direction, the heater is preferably arranged eccentrically toward the first end.

In order to maintain airtightness between the crucible and the plasma generation chamber,
It is desirable to include an elastic member that biases the crucible toward the wall surface of the plasma generation chamber using an elastic force.

To reduce the effects of radiant heat from the plasma generation chamber,
It is desirable to have a heat shield between the plasma generation chamber and the crucible.

As a method of generating aluminum-containing steam,
Supplying a chlorine-containing gas to a crucible in which an aluminum-containing solid material is placed and heating the crucible,
Aluminum-containing vapor is produced within the crucible.

To vaporize a solid material containing aluminum, it is necessary to heat it to a relatively high temperature, but if it is a reaction product with chlorine, the temperature required for vaporization is low. The generation of contained steam becomes easy.

In order to vaporize the aluminum-containing solid material itself, it is necessary to heat the solid material to a high temperature, but in the case of aluminum chloride, which is a reaction product with chlorine, the temperature to vaporize it is low. This facilitates the production of aluminum-containing vapor.
The vaporization temperature of aluminum chloride is lower than the surface temperature of the extraction electrode during ion source operation, so even if aluminum-containing vapor, mainly aluminum chloride, adheres to the extraction electrode, it will not be deposited on the extraction electrode. Evaporate. As a result, the problem of insulating the extraction electrode does not occur, and the operating rate of the ion source is improved to a great extent.
Further, since there is no problem with insulation of the extraction electrode, hydrogen gas is not required, and various problems that have occurred with the use of hydrogen gas are also solved.

Schematic cross-sectional view of the ion source Enlarged view of the first nozzle Cross-sectional view taken along line AA in Figure 1 Cross-sectional view when looking in the Z direction in Figure 3 Schematic cross-sectional view of the ion source in Figure 1 viewed from the ZX plane Schematic cross-sectional view of an ion source with a changed first nozzle Schematic cross-sectional view of an ion source with an eccentrically arranged heater Schematic cross-section of ion source with added heat shield Explanatory diagram of a configuration with multiple heat shields Schematic cross-sectional view of an ion source with an insulating member attached to the first nozzle Enlarged view of the area around the first nozzle shown in Figure 10 Perspective view of insulating member Explanatory diagram of how to install insulation members Explanatory diagram of how to install insulation members A schematic cross-sectional view of an ion source in which the crucible and the second nozzle are made of a single member. Schematic cross-sectional view of an ion source with solid material placed throughout the crucible Flowchart showing the method for producing aluminum-containing steam Flowchart showing another method for producing aluminum-containing steam

FIG. 1 is a schematic cross-sectional view of the ion source IS. The ion source IS is an indirectly heated cathode (IHC) ion source. In this ion source IS, the filament 23 heats the cathode 22, and the heated cathode 22 emits ionized electrons into the plasma generation chamber 21. A reflective electrode 24 is arranged inside the plasma generation chamber 21 so as to face the cathode 22 . A negative voltage is applied to the reflective electrode 24 by a power source (not shown), and ionized electrons emitted from the cathode 22 toward the reflective electrode 24 are reflected toward the cathode 22 near the reflective electrode 24.

An electromagnet (not shown) is arranged outside the plasma generation chamber 21 . This electromagnet generates a magnetic field inside the plasma generation chamber 21 along the direction in which the cathode 22 and the reflective electrode 24 face each other. The ionized electrons emitted from the cathode 22 are captured by the magnetic field generated by the electromagnet and directed toward the reflective electrode 24, thereby preventing the ionized electrons from disappearing due to collision with the inner wall of the plasma generation chamber 21.

Steam containing aluminum is supplied from the vaporizer 1 into the plasma generation chamber 21 . In the plasma generation chamber 21, plasma P is generated from aluminum-containing vapor. The ion beam IB containing aluminum ions is extracted from the ion extraction port 25 of the plasma generation chamber 21 by the extraction electrode E.

In FIG. 1, the extraction electrode E is composed of a suppression electrode 29 and a ground electrode 30. In the XY plane of FIG. 1, each electrode is a flat or disc-shaped electrode, and has a hole in the center through which the ion beam IB passes.
The suppression electrode 29 is an electrode for preventing electrons from flowing into the plasma generation chamber 21 from the downstream side (Z direction side) of the extraction electrode E. The ground electrode 30 is an electrode for fixing the ground potential.
The extraction electrode E shown in FIG. 1 is an example, and the structure and number of extraction electrodes E may be changed as appropriate depending on the configuration of the ion source.

The vaporizer 1 includes a crucible 2 in which an aluminum-containing solid material 7 (eg, pure aluminum, aluminum nitride, aluminum oxide, etc., including powdered materials) is placed.
The crucible 2 illustrated in FIG. 1 is a cylindrical member that is long in one direction (Z direction). A steam discharge port 2 a for supplying aluminum-containing steam to the plasma generation chamber 21 is provided at one longitudinal end of the crucible 2 . A chlorine-containing gas inlet 2b for supplying chlorine-containing gas to the crucible 2 is provided at the other end of the crucible 2 in the longitudinal direction.
In some embodiments, the chlorine-containing gas may be, for example, chlorine gas (Cl ₂ ) or hydrogen chloride gas (HCl). Additionally, the gas may be isotopically enriched.

A first nozzle 3 and a second nozzle 4 are detachably attached to the crucible 2. The first nozzle 3 and the second nozzle 4 are each elongated cylindrical members.
In some embodiments, the material of the first nozzle 3, second nozzle 4 and crucible 2 is graphite. However, graphite is only one example and other materials may be used.

Various methods can be used to attach the first nozzle 3 and the second nozzle 4 to the crucible 2 (for example, fitting and/or screwing). The first nozzle 3 extends the steam outlet 2a of the crucible 2, and the second nozzle 4 extends the chlorine-containing gas inlet 2b of the crucible 2.

In FIG. 1, arrow G indicates the flow of chlorine-containing gas supplied to crucible 2. The chlorine-containing gas is supplied from the first gas supply source 11 to the plasma generation chamber 21 through the first valve 12, first pipe 13, second nozzle 4, crucible 2, and first nozzle 3 in this order. The chlorine-containing gas reacts with the aluminum-containing solid material 7 to generate aluminum chloride (AlCl ₃ ) and the like. By heating the generated aluminum chloride, etc., aluminum-containing vapor containing aluminum particles is generated. Finally, this aluminum-containing vapor is supplied to the plasma generation chamber 21 through the first nozzle 3.

In some embodiments, the aluminum-containing solid material 7 is pure aluminum with a purity of 99.90% or greater. Pure aluminum increases the proportion of aluminum in aluminum-containing vapors compared to other materials. It is desirable to use pure aluminum for the solid material 7 in order to increase the amount of beam current derived from aluminum in the ion beam extracted from the ion source IS.
However, the aluminum-containing solid material 7 is not limited to pure aluminum. In some embodiments, aluminum nitride, aluminum oxide and/or other aluminum-containing solid materials may be used.

As shown in FIG. 1, the chlorine-containing gas may be supplied to the second nozzle 4 via a piping attachment member 9 fitted inside the second nozzle 4. For example, in some embodiments, the chlorine-containing gas may be supplied directly from the first pipe 13 to the second nozzle 4.
In some embodiments, the crucible 2, the first nozzle 3, the second nozzle 4, and other members that serve as flow paths for the chlorine-containing gas may be made of a corrosion-resistant material (e.g., carbon material). .

The tip 3 a of the first nozzle 3 projects inside the plasma generation chamber 21 . Openings are formed in the tip 3a to release steam in four orthogonal directions.
By using the above-described configuration, it is possible to diffuse the supply of aluminum-containing vapor to the plasma generation chamber 21 and generate uniform plasma.
In the embodiment shown in FIG. 1, the opening formed in the tip portion 3a also serves as the first gas introduction port 27 into the plasma generation chamber 21.

FIG. 2 is an enlarged view of the first nozzle 3 shown in FIG. The broken line in FIG. 2 is the steam discharge port 2a extended by the first nozzle 3, through which the chlorine-containing gas and the aluminum-containing steam pass. The steam outlet 2a communicates with an opening H of the tip 3a of the first nozzle 3. Each opening H is connected to the inside and outside of the first nozzle 3 in four directions: front, back, left, and right in the drawing.

In FIGS. 1 and 2, the tip end 3a has four openings H, but the number of openings H is not limited to four.
In some embodiments, the number of openings H may be less than four, or more than four. When the number of openings H increases, the aluminum-containing vapor can be discharged into the plasma generation chamber 21 from more directions, thereby improving the effect of distributing and supplying the vapor inside the plasma generation chamber 21.

Returning to FIG. 1, a heater 5 (a linear or sheet-like coil) having a thermocouple is spirally wound around the crucible 2. This heater 5 is used to heat the crucible 2 and vaporize reaction products such as aluminum chloride produced in the crucible 2. A first heat shield 6 is arranged around the outer periphery of the heater 5 to block heat emitted from the heater 5.
The heater 5 is not limited to a coil, and various types of heaters may be used. Alternatively, a plurality of heaters 5 may be provided, and the temperature control at the center and ends of the crucible 2 may be made independent.

In some embodiments, the second nozzle 4 has a large diameter portion 4a. Additionally, a mounting flange 8 is provided to attach the vaporizer 1 to the ion source flange 26.
In FIG. 1, the ion source flange 26 indirectly connects the plasma generation chamber 21 and other components disposed near the plasma generation chamber 21 (for example, the filament 23 and the cathode 22) by supporting parts not shown. I support it. The ion source flange 26 is a flange used when the ion source IS is assembled into a semiconductor manufacturing device, typically an ion implantation device. When the ion source IS is assembled into an ion implantation apparatus, the plasma generation chamber 21 side with the ion source flange 26 in between is placed in a vacuum, and the opposite side is placed in the atmosphere.

An elastic member 10 (for example, a coil spring) may be provided between the mounting flange 8 and the large diameter portion 4a of the second nozzle 4. The elastic member 10 keeps the space between the first nozzle 3 and the plasma generation chamber 21 airtight and prevents aluminum-containing vapor and/or chlorine-containing gas from flowing out. Since the first nozzle 3 is attached to the crucible 2, it can be said that the elastic member 10 is a member that urges the crucible 2 toward the outer wall surface of the plasma generation chamber 21 by elastic force.
Further, the elastic member 10 is not limited to a coil spring, and other structures such as a plate spring may be used.

In some embodiments, one or more gaskets (not shown) are provided between the vaporizer 1 and the outer wall surface of the plasma generation chamber 21 in order to maintain airtightness between the first nozzle 3 and the plasma generation chamber 21. may be provided.
In some embodiments, a damper (for example a snap ring or a spring clip) may be attached to the first nozzle 3 to avoid excessive pressure due to the elastic force of the elastic member 10.
In still another embodiment, in order to prevent excessive pressure due to the elastic force of the elastic member 10, a damper (for example, a snap ring or a spring clip) may be provided.
In some embodiments, one or all of one or more gaskets and/or dampers may be provided.
The gaskets and dampers are exemplary only, and different or additional structures may be used in other embodiments.

FIG. 3 is a cross-sectional view taken along line AA shown in FIG. The upper end of the aluminum-containing solid material 7 coincides with the lower end of the chlorine-containing gas inlet 2b.
FIG. 4 is a cross-sectional view of FIG. 3 when viewed in the Z direction. The configuration is similar to that of FIG. 3, and the upper end of the aluminum-containing solid material 7 coincides with the lower end of the steam outlet 2a.

With the above configuration, since the chlorine-containing gas flows along the surface of the aluminum-containing solid material 7, the chlorine-containing gas and the aluminum-containing solid material 7 can be reacted efficiently. That is, the configuration shown in FIG. 3 is advantageous in that the reaction between the chlorine-containing gas and the aluminum-containing solid material 7 is promoted.
As shown in FIG. 3, in some embodiments, the aluminum-containing solid material 7 may be semi-circular in cross-section. However, this configuration is only an example, and in other embodiments, the cross-sectional shape of the aluminum-containing solid material 7 can be changed depending on the cross-sectional shape of the crucible 2. Note that if the aluminum-containing solid material 7 does not completely block the chlorine-containing gas inlet 2b of the second nozzle 4 and the steam discharge port 2a of the first nozzle 3, the aluminum-containing solid material 7 may be larger or more Can be made into small shapes.

In some embodiments, the aluminum-containing solid material 7 is provided as a plurality of rods and/or plates extending longitudinally of the crucible 2 to facilitate the reaction between the chlorine-containing gas and the aluminum-containing solid material 7. may be done.
In such a configuration, the rods and/or plates may be suspended inside the crucible 2 by supports.
In some embodiments, the diameter of the crucible 2 in the XY plane may be equivalent to the diameters of the chlorine-containing gas inlet 2b and the steam outlet 2a.

With the semicircular cross-section of the aluminum-containing solid material 7, substantially half of the internal volume of the crucible 2 (e.g. the upper half in the example shown in FIGS. 3 and 4) is an open space from which the aluminum-containing vapor can be obtained. becomes.
Considering the efficiency of supplying aluminum-containing vapor to the plasma generation chamber 21, it is advantageous to have a smaller open space. However, if the open space is too small, the pressure inside the crucible 2 will increase due to aluminum-containing vapor vaporized by heat transfer from the plasma generation chamber 21 after heating by the heater 5 is stopped, and the pressure inside the crucible 2 will increase, making it unnecessary for the plasma generation chamber 21. There is concern that aluminum-containing vapor may leak out.

During operation of the ion source IS, the temperature of the extraction electrode E is approximately 400 to 500°C. The boiling point of aluminum chloride contained in aluminum-containing vapor is about 180° C., although it varies depending on the pressure at the location where aluminum chloride is produced. For this reason, deposits derived from aluminum chloride, which is the main component of the aluminum-containing vapor, are not deposited on the surface of the extraction electrode E but evaporate.
Therefore, in the ion source IS in the various embodiments described above, the problem that the extraction electrode E becomes insulated over time and the electrode surface needs to be cleaned is avoided. That is, in the ion source IS in various embodiments, there is no need to use hydrogen gas in order to avoid the problem of insulating the extraction electrode E, as in the prior art.

Ionic species other than aluminum ions are also used to create PN junctions in SiC devices. Gases that are sources of ion species other than aluminum ions (PH ₃ , PF ₃ , BF ₃ , N _{2 ,} etc.) are sent to the plasma generation chamber 21 through the same flow path as the chlorine-containing gas and aluminum-containing vapor in the vaporizer 1. May be supplied.
However, reaction products generated by the reaction between the aluminum-containing solid material 7 in the crucible 2 and other gas species, and reaction products between the residual gas and/or residual vapor in the flow path and other gas species. Other reaction products may cause problems such as unexpected discharge. For this reason, it is desirable to provide a flow path for other gas types separately from the flow path for chlorine-containing gas and aluminum-containing vapor.
That is, aluminum-containing vapor is supplied from the first gas inlet 27 to the plasma generation chamber 21, and gas that becomes a source of ion species other than aluminum ions is supplied to the plasma generation chamber 21 from the second gas inlet 28.

FIG. 5 is a schematic cross-sectional view of the ion source IS in the ZX plane in various embodiments. In FIG. 5, the same reference numbers as in FIG. 1 refer to the same elements, and their repeated description will be omitted for the sake of brevity. This also applies to other figures described later.
A second gas inlet 28 is connected to the wall surface of the plasma generation chamber 21 to which an L-shaped joint 34 (hatched member in the figure) is connected for supplying other gas types into the plasma generation chamber 21. is provided.

For example, in some embodiments, other gas species comprising components other than aluminum can be supplied from the second gas source 31 via the second valve 32. The specific configuration of the second gas supply source 31 is limited to the illustrated configuration as long as it can supply other gas types to the second piping 33 and finally to the second gas inlet 28. It is not something that will be done.

In the above embodiment, the IHC ion source was described as an example of the ion source IS. However, the IHC ion source is only one embodiment; other embodiments may use other types of ion sources as the ion source IS, such as a Bernas ion source, an inductively coupled plasma (ICP) ion source, etc. You can.

Although FIG. 1 shows a configuration in which the tip 3a of the first nozzle 3 protrudes into the plasma generation chamber 21, this configuration is only an example.
In other embodiments, as in the ion source IS illustrated in FIG. You may choose to stay inside. That is, the tip portion 3a of the first nozzle 3 may be configured not to protrude into the plasma generation chamber 21. In the configuration shown in FIG. 6, the number of openings H formed in the tip 3a of the first nozzle 3 is one in the Z direction.

1 and 6 depict an example of an ion source IS provided with one first nozzle 3 and one second nozzle 4. However, in some embodiments, for example, a plurality of second nozzles 4 may be provided for the purpose of increasing the contact area between the chlorine-containing gas and the aluminum-containing solid material 7. Further, the number of first nozzles 3 is not limited to one, and may be plural in order to individually supply aluminum-containing vapor to a plurality of locations in the plasma generation chamber 21.

During operation of the ion source IS, the heat in the plasma generation chamber 21, which has become high in temperature, is transferred to the crucible 2 through the first nozzle 3. Furthermore, the heat in the crucible 2 escapes to the outside through the second nozzle 4.
Due to such heat transfer, when a temperature gradient occurs in the temperature distribution of the crucible 2 in the Z direction in FIG. 1, the consumption of the solid material 7 becomes uneven depending on the temperature gradient. This makes it difficult to control the temperature of the crucible 2 by the heater 5, to control the amount of aluminum-containing vapor generated due to the temperature control, and to set the beam current amount of the ion beam containing aluminum to a desired value.

In order to equalize the temperature distribution in the Z direction of the crucible 2, some configurations may be changed or added in the embodiments described so far.
In comparison with the configuration in FIG. 1, in FIG. 7, the mounting position of the heater 5 has been changed. In the Z direction, the crucible 2 can be divided into three parts. Specifically, each part includes a first end 2d including the chlorine-containing gas inlet 2b, a second end 2e including the steam discharge port 2a, and a second end 2e between the first end 2d and the second end 2e. The main body part 2c is located there.
With respect to the center position C1 of the crucible 2 in the Z direction, the center position C2 of the heater 5 in the same direction is biased toward the first end 2d side. With such an eccentric arrangement of the heater 5, heating can be focused on the second nozzle 4 side where heat escapes, so that uneven temperature distribution in the crucible 2 can be reduced.
On the other hand, when the temperature of the crucible 2 on the plasma generation chamber 21 side is made high, the center position C2 of the heater 5 may be eccentrically arranged on the opposite side from the embodiment of FIG.

In FIG. 8 , a second heat shield 41 is placed between the plasma generation chamber 21 and the crucible 2 . The second heat shield 41 is, for example, a flat heat shield in the XY plane, and is a member in which an opening for inserting the first nozzle 3 is formed in the center. By providing the second heat shield 41, it is possible to reduce radiant heat from the plasma generation chamber 21 to the crucible 2.
The embodiment of FIG. 8 adopts a configuration in which a second heat shield 41 is added to the embodiment of FIG. 7, but the second heat shield 41 is added to the embodiment of FIG. A configuration in which 41 is added may also be adopted.
The number of second heat shields 41 is not limited to the one illustrated, but may be multiple. For example, as shown in FIG. 9, when a plurality of second heat shields 41 are used, it is desirable to form a convex portion 43 on each shield to ensure a gap between each shield. With such a gap, when the ion source IS is placed in a vacuum, the vacuum heat insulation effect in each gap makes it possible to reduce the radiant heat from the plasma generation chamber 21 in various stages.

In addition to radiation, heat from the plasma generation chamber 21 is transmitted to the crucible 2 through the first nozzle 3 . In the embodiment of FIG. 10, an insulating member 42 is attached to the first nozzle 3 for the purpose of reducing heat transfer due to contact between members. The insulating member 42 is a member having a lower thermal conductivity than the first nozzle 3, and is, for example, an insulator such as aluminum oxide or aluminum nitride.
The structure of the first nozzle 3 and the insulating member 42 and how to assemble each member will be explained using FIGS. 11 to 14.

FIG. 11 is an enlarged view of the first nozzle 3 and the insulating member 42 shown in FIG. 10. FIG. 12 is a perspective view of only the insulating member 42 taken out. The outer wall of the insulating member 42 is provided with a protrusion T projecting outward.
The first nozzle 3 has a linear portion 3b forming the steam discharge port 2a, a ring-shaped connecting portion 3d extending in a direction 90 degrees different from the linear portion 3b, and a bent portion 3c bent in multiple directions. ing.
As shown in FIG. 12, an opening W into which the straight portion 3b of the first nozzle 3 is inserted is formed in the center of the insulating member 42. As shown in FIG. 11, when each member is assembled, the protrusion T of the insulating member 42 is arranged in the gap S formed inside the bent part 3c (on the straight part 3b side).

13 and 14 are more detailed explanatory diagrams of the assembly of the first nozzle 3 and the insulating member 42. FIG. Each figure shows the first nozzle 3 shown in FIG. 10 viewed from the direction U shown in the drawing.
In FIG. 13, a partial notch V for allowing the protrusion T of the insulating member 42 to fall into the gap S is formed in the bent portion 3c. By aligning the protrusion T of the insulating member 42 with this notch V and moving the insulating member 42 toward the connecting portion 3d side (backward side in the figure), the insulating member 42 is inserted into the gap S of the first nozzle 3. 42 protrusions T are arranged.

The gap S is formed around the linear portion 3b of the first nozzle 3, and allows the protrusion T of the insulating member 42 to rotate. In FIG. 13, after the protrusion T of the insulating member 42 is placed in the gap S, the insulating member 42 is rotated 90 degrees. At this time, the positions of the protrusions T of the insulating member 42 move from the positions 270 and 90 in FIG. 13 to the positions 0 and 180 in FIG. By using such an assembly structure, it is possible to prevent the insulating member 42 from falling off from the first nozzle 3.
By using such an insulating member 42, heat transfer from the plasma generation chamber 21 to the first nozzle 3 is reduced.

Unlike the embodiment described above, the first nozzle 3 may be made of a material with low thermal conductivity without using the insulating member 42.
Further, the configurations of the first nozzle 3 and the insulating member 42 described in FIGS. 11 to 14 are merely examples, and other configurations may be adopted. The tip portion 3a of the first nozzle 3 may be formed of an insulating member 42, and the insulating member 42 may be screwed onto the first nozzle 3.

In order to adjust the temperature gradient of the crucible 2, the crucible 2 and the second nozzle 4 may be integrally molded and constituted by a single member, as shown in FIG. 15. Further, the crucible 2 and the first nozzle 3 may be integrally molded, or both the first nozzle 3 and the second nozzle 4 may be integrally molded with the crucible 2.

In order to improve the usage efficiency of the chlorine-containing gas introduced into the crucible 2, it is desirable to increase the contact area between the chlorine-containing gas and the aluminum-containing solid material 7. In FIG. 16, the solid material 7 is placed throughout the crucible 2. In this case, the solid material 7 is a porous body in which a large number of holes are formed through which chlorine-containing gas passes, or it is composed of a collection of fine solid materials in the form of powder or pellets.
In order to release the aluminum-containing steam from the steam outlet 2a, the illustrated solid material 7 is designed so that when the chlorine-containing gas is introduced, the aluminum-containing steam and a small amount of the chlorine-containing gas flow out through the steam outlet 2a. It is configured.

17 and 18 are embodiments of a method for producing aluminum-containing steam.
In the embodiment of FIG. 17, first, a chlorine-containing gas is supplied to the crucible 2 in which the aluminum-containing solid material 7 is placed (processing S1). Next, the crucible 2 is heated with the heater 5 until the temperature reaches a predetermined temperature (processing S2).
In the process S1, aluminum chloride, which is a reaction product of the aluminum-containing solid material 7 and the chlorine-containing gas, is produced. In process S2, aluminum-containing vapor is generated by heating the generated aluminum chloride to a predetermined temperature.

On the other hand, in the embodiment of FIG. 18, compared to the embodiment of FIG. 17, the order of processing S1 and processing S2 is reversed. Even if the process S2 is performed first and the crucible 2 is heated to a predetermined temperature with the heater 5 as in the embodiment of FIG. 18, aluminum vapor can be generated in the same manner as in FIG. The reason for this is that if there is no aluminum chloride produced in the process S1, no aluminum-containing vapor will be produced even if the temperature of the crucible 2 is heated to a predetermined temperature. From this, the order in which processing S1 and processing S2 are performed may be performed in any order.

In addition, it goes without saying that the present invention is not limited to the embodiments described above, and that various modifications can be made without departing from the spirit thereof. May be combined.

1 : Vaporizer 2 : Crucible 2a : Steam discharge port 2b : Chlorine-containing gas inlet 2c : Main body part 2d : First end part 2e : Second end part 3 : First nozzle 3a : Tip part 4 : Second nozzle 5 : Heater 7 : Solid material 10 : Elastic member 11 : First gas supply source 21 : Plasma generation chamber 27 : First gas inlet 28 : Second gas inlet 41 : Second heat shield IS : Ion source

Claims (9)

a crucible in which an aluminum-containing solid material is placed;
and a heater that heats the crucible,
The crucible includes a chlorine-containing gas inlet for introducing a chlorine-containing gas into the crucible;
A vaporizer, the vaporizer having a vapor discharge port for discharging aluminum-containing vapor generated by heating a reaction product of the chlorine-containing gas and the solid material to the outside of the crucible. A vaporizer according to claim 1, wherein the solid material is pure aluminum. The vaporizer of claim 1, wherein the vapor outlet releases the aluminum-containing vapor in multiple directions. The vaporizer according to claim 1;
It has a plasma generation chamber that generates plasma inside,
An ion source that emits the aluminum-containing vapor into the plasma generation chamber through a wall surface of the plasma generation chamber. The plasma generation chamber has a first gas inlet and a second gas inlet,
The aluminum-containing vapor is supplied to the first gas inlet through the vaporizer,
5. The ion source according to claim 4, wherein a gas made of a component other than aluminum is supplied to the second gas inlet. The crucible is
a first end including the chlorine-containing gas inlet, a second end including the steam discharge port, and a main body between the first end and the second end in a first direction. ,
The ion source according to claim 4, wherein the heater is eccentrically arranged toward the first end in the first direction. The ion source according to claim 4, further comprising an elastic member that biases the crucible toward a wall surface of the plasma generation chamber using an elastic force. The ion source according to claim 4, further comprising a heat shield between the plasma generation chamber and the crucible. Supplying a chlorine-containing gas to a crucible in which an aluminum-containing solid material is placed and heating the crucible,
A method for producing aluminum-containing steam, comprising producing aluminum-containing steam in the crucible.