Vaporizer, ion source including the same, and method for generating aluminum-containing vapor

Abstract

To provide a new vaporizer capable of solving a 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 disposed, and a heater 5 that heats the crucible 2, wherein the crucible 2 has a chlorine-containing gas inlet 2b through which a chlorine-containing gas is introduced into the crucible 2, and a vapor outlet 2a through which an aluminum-containing vapor generated by a reaction product of the chlorine-containing gas and the solid material 7 being heated is discharged to the outside of the crucible 2, and the chlorine-containing gas does not contain dopant components in an ion implantation process.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vaporizer, an ion source having the vaporizer, and a method for producing an aluminum-containing vapor. [Background technology]

[0002] Silicon carbide (SiC) devices are expected to be used in high-voltage, high-temperature applications such as electric vehicles, railways, and power plants. The manufacturing process for SiC devices is similar to that for conventional silicon devices in that it uses an ion implantation process.

[0003] In the ion implantation process for SiC devices, nitrogen ions or phosphorus ions are implanted as N-type dopants, and aluminum ions or boron ions are implanted as P-type dopants into the SiC wafer to fabricate PN junctions.

[0004] Nitrogen ions, phosphorus ions, and boron ions are generated by turning the raw material gas into plasma. On the other hand, when generating aluminum ions, there is no optimal gas as a raw material, and therefore an aluminum-containing solid material and an auxiliary gas, typically a fluorine-containing gas, are used.

[0005] Patent Document 1 discloses a method for generating an ion beam containing aluminum ions using a solid material containing aluminum. The aluminum-containing solid material is placed in the plasma generation chamber of the ion source. Next, a corrosive gas containing fluorine, 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.

[0006] The aluminum-containing solid material is supported on a repeller to which a negative voltage is applied, and fluorine ions in the plasma are attracted to the repeller, physically sputtering the aluminum-containing solid material. On the other hand, fluorine radicals in the plasma chemically react with the aluminum-containing solid material, chemically sputtering the aluminum-containing solid material. Physical and chemical sputtering causes aluminum particles to be released from aluminum-containing solid materials.

[0007] Aluminum particles emitted from the solid material collide with high-energy electrons emitted from the cathode in the plasma generation chamber and are ionized, producing aluminum ions in the plasma derived from the corrosive gas. An ion extraction port for extracting an ion beam is formed on one side of the plasma generation chamber. An extraction electrode disposed adjacent to the plasma generation chamber extracts an ion beam containing aluminum ions from the plasma in the plasma generation chamber through the ion extraction port. The extracted ion beam is subjected to mass analysis along the ion beam transport path and then irradiated onto a SiC wafer, thereby implanting aluminum ions into the SiC wafer. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent Publication No. 2011-124059 [Patent Document 2] Patent Publication No. 2014-502409 Summary of the Invention [Problem to be solved by the invention]

[0009] During operation of the ion source, aluminum fluoride (AlF3), a reaction product of fluorine and aluminum, and reaction products of fluorine and the high-melting-point materials (tungsten and molybdenum) that make up the extraction electrode, are deposited on the surface of the extraction electrode. These deposits are insulating materials, and over time, the deposits cover the surface of the extraction electrode, making the electrode insulating. If the extraction electrode becomes insulated, it becomes impossible to extract the desired ion beam, so the operation of the ion source is temporarily stopped and the deposits on the extraction electrode are cleaned off.

[0010] However, cleaning the extraction electrode poses a problem of reduced availability of the ion source. Therefore, to solve the problem of electrode insulation while improving the availability of the ion source, a method using hydrogen gas, as disclosed in Patent Document 2, has been proposed. In this method, hydrogen gas is introduced into the plasma generation chamber during operation of the ion source, and reacts with the fluorine component that causes electrode insulation, thereby generating hydrogen fluoride (gas). Finally, the generated hydrogen fluoride is exhausted to the outside of the device using a vacuum pump. Using this method reduces the amount of deposits that accumulate on the extraction electrode, thereby extending the period until the extraction electrode needs to be cleaned, thereby improving the availability of the ion source. However, the method of Patent Document 2 requires a large amount of hydrogen gas, which poses problems such as the need for gas supply piping for hydrogen gas and the increased complexity of gas management due to the increased number of gases to be managed.

[0011] Therefore, we provide a new vaporizer, an ion source equipped with the same, and a method for generating aluminum-containing vapor that can solve the problem of insulating the extraction electrode without using hydrogen gas and improve the operating rate of the ion source. [Means for solving the problem]

[0012] The vaporizer is a crucible having an aluminum-containing solid material disposed therein; a heater for heating the crucible, The crucible has a chlorine-containing gas inlet for introducing a chlorine-containing gas into the crucible; a vapor outlet for discharging aluminum-containing vapor generated by heating the reaction product of the chlorine-containing gas and the solid material to the outside of the crucible; death, The chlorine-containing gas is characterized by not containing a dopant component in the ion implantation process.

[0013] The ion source is configured as follows: The vaporizer; A plasma generation chamber is provided inside to generate plasma, The aluminum-containing gas is introduced into the plasma generation chamber through the wall of the plasma generation chamber. Preferably, it is an ion source that emits vapor.

[0014] Methods for generating aluminum-containing vapor include: A crucible containing aluminum-containing solid material is placed It does not contain dopant components in the ion implantation process. supplying a chlorine-containing gas and heating the crucible; An aluminum-containing vapor is generated within the crucible. [Effects of the Invention]

[0015] Vaporizing an aluminum-containing solid material itself requires high-temperature heating of the solid material, but if aluminum chloride, a reaction product with chlorine, is used, the temperature for vaporizing it can be lowered, making it easier to generate aluminum-containing vapor. The vaporization temperature of aluminum chloride is lower than the surface temperature of the extraction electrode during operation of the ion source, and even if aluminum-containing vapor, mainly aluminum chloride, adheres to the extraction electrode, it evaporates without being deposited on the electrode. This prevents insulation problems on the extraction electrode, significantly improving the operating rate of the ion source. Furthermore, since the problem of insulating the extraction electrode does not arise, hydrogen gas is no longer necessary, and the various problems that arise with the use of hydrogen gas are also resolved. [Brief explanation of the drawings]

[0016] [Figure 1] Schematic cross-sectional view of the ion source [Figure 2] Enlarged view of No. 1 nozzle [Figure 3] Cross section of line AA in Figure 1 [Figure 4] Cross-sectional view of Figure 3 when viewed from the Z direction [Figure 5]Schematic cross-sectional view of the ion source in Figure 1 as seen from the ZX plane [Figure 6] Schematic cross-sectional view of an ion source with a modified first nozzle [Figure 7] Schematic cross-sectional view of an ion source with an eccentrically placed heater [Figure 8] Schematic cross-section of the ion source with the heat shield added [Figure 9] An explanatory diagram of a configuration with multiple heat shields [Figure 10] Schematic cross-sectional view of an ion source with an insulating member attached to the first nozzle [Figure 11] Enlarged view of the first nozzle and its surroundings shown in Figure 10 [Figure 12] A perspective view of an insulating member [Figure 13] Illustration of how to attach the insulating material [Figure 14] Illustration of how to attach the insulating material [Figure 15] Schematic cross-sectional view of an ion source in which the crucible and second nozzle are made of a single member [Figure 16] Schematic cross-sectional view of an ion source with solid material placed throughout the crucible [Figure 17] Flowchart showing a method for producing aluminum-containing vapor [Figure 18] 1 is a flowchart illustrating another method for producing aluminum-containing vapor. DETAILED DESCRIPTION OF THE INVENTION

[0017] 1 is a schematic cross-sectional view of an ion source IS. The ion source IS is an indirectly heated cathode (IHC) ion source. In this ion source IS, a filament 23 heats a cathode 22, and the heated cathode 22 emits ionization electrons into a plasma generation chamber 21. A reflecting electrode 24 is disposed inside the plasma generation chamber 21, facing the cathode 22. A negative voltage is applied to the reflecting electrode 24 by a power supply (not shown), and the ionization electrons emitted from the cathode 22 toward the reflecting electrode 24 are reflected toward the cathode 22 near the reflecting electrode 24.

[0018] An electromagnet (not shown) is disposed outside the plasma generation chamber 21. This electromagnet generates a magnetic field inside the plasma generation chamber 21 along the opposing direction of the cathode 22 and the reflecting electrode 24. Ionized electrons emitted from the cathode 22 are captured by the magnetic field generated by the electromagnet and directed toward the reflecting electrode 24, thereby preventing the ionized electrons from colliding with the inner wall of the plasma generation chamber 21 and being lost.

[0019] Vapor 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 the vapor containing aluminum. An ion beam IB containing aluminum ions is extracted from an ion extraction port 25 of the plasma generation chamber 21 by an extraction electrode E.

[0020] 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 disk-shaped electrode with 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 electrodes E shown in FIG. 1 are merely exemplary, and the structure and number of the extraction electrodes E may be changed as appropriate depending on the configuration of the ion source.

[0021] The vaporizer 1 includes a crucible 2 in which an aluminum-containing solid material 7 (for example, pure aluminum, aluminum nitride, aluminum oxide, etc., including powdered materials) is placed. 1 is a cylindrical member that is long in one direction (Z direction). One longitudinal end of the crucible 2 is provided with a vapor outlet 2a for supplying aluminum-containing vapor to the plasma generation chamber 21. The other longitudinal end of the crucible 2 is provided with a chlorine-containing gas inlet 2b for supplying chlorine-containing gas to the crucible 2. In some embodiments, the chlorine-containing gas may be, for example, chlorine gas (Cl) or hydrogen chloride gas (HCl). Additionally, the gas may be isotopically enriched.

[0022] 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 an elongated cylindrical member. In some embodiments, the material of the first nozzle 3, the second nozzle 4, and the crucible 2 is graphite. However, graphite is only an example and other materials may be used.

[0023] Various methods (for example, fitting and / or screwing) can be used to attach the first nozzle 3 and the second nozzle 4 to the crucible 2. The first nozzle 3 extends the vapor outlet 2a of the crucible 2, and the second nozzle 4 extends the chlorine-containing gas inlet 2b of the crucible 2.

[0024] In FIG. 1, arrow G indicates the flow of chlorine-containing gas supplied to crucible 2. The chlorine-containing gas is supplied from first gas supply source 11 through first valve 12 and first piping 13, passing through second nozzle 4, crucible 2, and first nozzle 3 in this order, to plasma generation chamber 21. The chlorine-containing gas reacts with aluminum-containing solid material 7 to generate aluminum chloride (AlCl3) and the like. Heating the generated aluminum chloride and the like generates aluminum-containing vapor containing aluminum particles. Finally, this aluminum-containing vapor is supplied to plasma generation chamber 21 through first nozzle 3.

[0025] In some embodiments, the aluminum-containing solid material 7 is pure aluminum having a purity of 99.90% or greater. Pure aluminum increases the proportion of aluminum in the aluminum-containing vapor compared to other materials. Using pure aluminum as the solid material 7 is desirable in order to increase the amount of aluminum-derived beam current in the ion beam extracted from the ion source IS. However, the aluminum-containing solid material 7 is not limited to pure aluminum, and in some embodiments, aluminum nitride, aluminum oxide, and / or other aluminum-containing solid materials may be used.

[0026] 1, the chlorine-containing gas may be supplied to the second nozzle 4 via a piping fitting 9 fitted within the second nozzle 4. For example, in some embodiments, the chlorine-containing gas may be supplied directly to the second nozzle 4 from the first piping 13. In some embodiments, the crucible 2, the first nozzle 3, the second nozzle 4, and other components that serve as a passage for the chlorine-containing gas may be made of a corrosion-resistant material (for example, a carbon material).

[0027] A tip 3a of the first nozzle 3 protrudes into the inside of the plasma generation chamber 21. The tip 3a has openings formed therein for emitting steam in four directions that are perpendicular to each other. By using the above-described configuration, it becomes possible to diffuse the supply of aluminum-containing vapor into the plasma generation chamber 21 and generate uniform plasma. In the embodiment of FIG. 1, the opening formed in the tip portion 3a also serves as the first gas inlet 27 to the plasma generation chamber .

[0028] Figure 2 is an enlarged view of the first nozzle 3 shown in Figure 1. The dashed lines in Figure 2 indicate vapor outlets 2a extended by the first nozzle 3, through which the chlorine-containing gas and aluminum-containing vapor pass. The vapor outlets 2a communicate with openings H at 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, the front, back, left, and right, of the drawing.

[0029] In Figs. 1 and 2, the tip portion 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 4 or may be greater than 4. As the number of openings H increases, the aluminum-containing vapor can be emitted into the plasma generation chamber 21 from more directions, improving the vapor dispersion and supply effect inside the plasma generation chamber 21.

[0030] Returning to Fig. 1, a heater 5 (a wire or sheet-like coil) having a thermocouple is wound spirally 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 the heat emitted from the heater 5. The heater 5 is not limited to a coil and may be of various other shapes. Furthermore, a plurality of heaters 5 may be provided, and the temperature at the center and the ends of the crucible 2 may be controlled independently.

[0031] In some embodiments, the second nozzle 4 has an enlarged diameter portion 4a. A mounting flange 8 is also provided for mounting the vaporizer 1 to the ion source flange . 1, the ion source flange 26 supports components (not shown), thereby indirectly supporting the plasma generation chamber 21 and other components (e.g., the filament 23 and the cathode 22) disposed nearby the plasma generation chamber 21. The ion source flange 26 is a flange used when assembling the ion source IS to a semiconductor manufacturing device such as an ion implantation device. When the ion source IS is assembled to the ion implantation device, the plasma generation chamber 21 side of the ion source flange 26 is placed in a vacuum, and the opposite side is placed in the atmosphere.

[0032] An elastic member 10 (e.g., 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 maintains an airtight seal between the first nozzle 3 and the plasma generation chamber 21, preventing the aluminum-containing vapor and / or chlorine-containing gas from leaking out. Since the first nozzle 3 is attached to the crucible 2, the elastic member 10 can also be said to be a member that urges the crucible 2 toward the outer wall surface of the plasma generation chamber 21 by elastic force. Furthermore, the elastic member 10 is not limited to a coil spring, and other configurations such as a leaf spring may also be used.

[0033] In some embodiments, one or more gaskets (not shown) may be provided between the vaporizer 1 and the outer wall surface of the plasma generation chamber 21 to keep the gap between the first nozzle 3 and the plasma generation chamber 21 airtight. In some embodiments, a damper (for example, a snap ring or spring clip) may be attached to the first nozzle 3 to prevent excessive pressure due to the elastic force of the elastic member 10. In yet another embodiment, a damper (e.g., a snap ring or a spring clip) may be provided between the large diameter portion 4a of the second nozzle 4 and the inner wall of the first heat shield 6 to prevent excessive pressure due to the elastic force of the elastic member 10. 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 in other embodiments, different or additional structures may be used.

[0034] Fig. 3 is a cross-sectional view taken along the line AA in Fig. 1. 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 seen from the Z direction side in Fig. 3. It has the same configuration as Fig. 3, and the upper end of the aluminum-containing solid material 7 coincides with the lower end of the vapor discharge port 2a.

[0035] With the above configuration, the chlorine-containing gas flows along the surface of the aluminum-containing solid material 7, and therefore, it is possible to efficiently react the chlorine-containing gas with the aluminum-containing solid material 7. 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. 3, in some embodiments, the aluminum-containing solid material 7 may have a semicircular cross section. However, this configuration is merely 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 the aluminum-containing solid material 7 can be made larger or smaller inside the crucible 2 as long as it does not completely block the chlorine-containing gas inlet 2b of the second nozzle 4 and the vapor outlet 2a of the first nozzle 3.

[0036] In some embodiments, the aluminum-containing solid material 7 may be provided as a plurality of rods and / or plates extending longitudinally of the crucible 2 to facilitate reaction between the chlorine-containing gas and the aluminum-containing solid material 7. 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 equal to the diameter of the chlorine-containing gas inlet 2b and the vapor outlet 2a.

[0037] With a 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 examples shown in Figures 3 and 4) is open space from which aluminum-containing vapor can be obtained. A smaller open space is advantageous in terms of the efficiency of supplying aluminum-containing vapor to the plasma generation chamber 21. However, if the open space is too small, the pressure inside the crucible 2 may 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 there is a concern that unnecessary aluminum-containing vapor may flow into the plasma generation chamber 21.

[0038] During operation of the ion source IS, the temperature of the extraction electrode E reaches approximately 400 to 500°C. Although this varies depending on the pressure at the location where aluminum chloride is generated, the boiling point of aluminum chloride contained in the aluminum-containing vapor is approximately 180°C. For this reason, deposits derived from aluminum chloride, the main component of the aluminum-containing vapor, evaporate without being deposited on the surface of the extraction electrode E. Therefore, the ion source IS in the various embodiments described above avoids the problem that the extraction electrode E becomes insulated over time, requiring cleaning of the electrode surface. That is, the ion source IS in the various embodiments does not need to use hydrogen gas to avoid the insulation problem of the extraction electrode E, as in the conventional technology.

[0039] Ion species other than aluminum ions are also used to fabricate PN junctions in SiC devices. Gases (PH, PF, BF, N, etc.) that are sources of ion species other than aluminum ions may be supplied to plasma generation chamber 21 through the same flow path as the chlorine-containing gas and aluminum-containing vapor in vaporizer 1. However, reaction products generated by the reaction of aluminum-containing solid material 7 in crucible 2 with other gas species, or reaction products generated by the reaction of residual gas and / or residual vapor in the flow path with other gas species, may cause unexpected problems such as discharge. For this reason, it is desirable to provide flow paths for other gas species separately from the flow paths for the chlorine-containing gas and aluminum-containing vapor. That is, aluminum-containing vapor is supplied to the plasma generation chamber 21 from the first gas inlet 27, and gas that will become the source of ion species other than aluminum ions is supplied to the plasma generation chamber 21 from the second gas inlet .

[0040] Figure 5 is a schematic cross-sectional view of an ion source IS in the ZX plane according to various embodiments. In Figure 5, the same reference numerals as in Figure 1 refer to the same elements, and for the sake of brevity, repeated explanations will be omitted. This also applies to other figures described below. A second gas inlet 28 is provided on the wall surface of the plasma generation chamber 21 to which an L-shaped joint 34 (the hatched member in the figure) for supplying other gas species into the plasma generation chamber 21 is connected.

[0041] For example, in some embodiments, a gas species other than aluminum can be supplied from the second gas supply source 31 via the second valve 32. The specific configuration of the second gas supply source 31 is not limited to the configuration shown in the figure, as long as it is capable of supplying the other gas species to the second pipe 33 and ultimately to the second gas inlet 28.

[0042] In the above embodiment, an IHC ion source has been described as an example of the ion source IS. However, the IHC ion source is only one embodiment, and in other embodiments, other types of ion sources such as a Bernas ion source or a high-frequency inductively coupled plasma (ICP) ion source may be used as the ion source IS.

[0043] FIG. 1 shows a configuration in which the tip 3a of the first nozzle 3 protrudes into the plasma generation chamber 21, but this configuration is merely one example. In other embodiments, like the ion source IS illustrated in Fig. 6, the tip 3a provided on the first nozzle 3 may be flush with the inner wall surface of the plasma generation chamber 21 or may remain within the wall of the plasma generation chamber 21. In other words, the tip 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 in the Z direction is one.

[0044] 1 and 6 illustrate 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 in order to increase the contact area between the chlorine-containing gas and the aluminum-containing solid material 7. Furthermore, the number of first nozzles 3 is not limited to one, and a plurality of first nozzles 3 may be provided in order to individually supply aluminum-containing vapor to a plurality of locations in the plasma generation chamber 21.

[0045] During operation of the ion source IS, the heat of the plasma generation chamber 21, which has become high in temperature, is transferred to the crucible 2 through the first nozzle 3. In addition, the heat of the crucible 2 escapes to the outside through the second nozzle 4. 1, if a temperature gradient occurs in the temperature distribution of the crucible 2 in the Z direction, the solid material 7 will be consumed non-uniformly 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 as a result of the temperature control, and ultimately to achieve a desired beam current of the aluminum-containing ion beam.

[0046] In order to achieve a more uniform temperature distribution in the Z direction of the crucible 2, some configurations may be modified or added to the embodiments described above. 7, the mounting position of the heater 5 is changed compared to the configuration in FIG. 1. In the Z direction, the crucible 2 can be divided into three parts. Specifically, the parts are a first end 2d including a chlorine-containing gas inlet 2b, a second end 2e including a vapor outlet 2a, and a main body 2c located between the first end 2d and the second end 2e. The center position C2 of the heater 5 in the Z direction is biased toward the first end 2d relative to the center position C1 of the crucible 2. This eccentric arrangement of the heater 5 allows for focused heating of the second nozzle 4 side, where heat escapes, thereby reducing uneven temperature distribution in the crucible 2. Conversely, when the temperature of the crucible 2 on the plasma generation chamber 21 side is to be increased, the center position C2 of the heater 5 may be eccentrically arranged on the opposite side to the embodiment of FIG.

[0047] 8, a second heat shield 41 is disposed 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 having an opening formed in the center for inserting the first nozzle 3. By providing the second heat shield 41, it is possible to reduce the radiant heat from the plasma generation chamber 21 to the crucible 2. The embodiment of Figure 8 adopts a configuration in which a second heat shield 41 is added to the embodiment of Figure 7, but a configuration in which a second heat shield 41 is added to the embodiment of Figure 1 may also be adopted without using it in combination with the embodiment of Figure 7. The number of second thermal shields 41 is not limited to one as shown in the figure, and may be multiple. For example, as shown in Fig. 9, when multiple second thermal shields 41 are used, it is desirable to form convex portions 43 on each shield to ensure gaps between the shields. If such gaps are provided, and the ion source IS is disposed in a vacuum, the vacuum insulation effect in each gap can significantly reduce the radiant heat from the plasma generation chamber 21.

[0048] In addition to radiation, heat is transferred from the plasma generation chamber 21 to the crucible 2 through the first nozzle 3. In order to reduce heat transfer due to contact between members, in the embodiment of Fig. 10, an insulating member 42 is attached to the first nozzle 3. The insulating member 42 is a member with 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 these members will be described with reference to FIGS.

[0049] Fig. 11 is an enlarged view of the first nozzle 3 and insulating member 42 shown in Fig. 10. Fig. 12 is a perspective view of the insulating member 42 alone. The insulating member 42 has a protrusion T on its outer wall that protrudes outward. The first nozzle 3 has a straight portion 3b forming the steam discharge port 2a, a ring-shaped connecting portion 3d extending in a direction different by 90 degrees from the straight portion 3b, and a bent portion 3c bent in multiple directions. 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 the components are assembled, a protrusion T of the insulating member 42 is disposed in a gap S formed inside the bent portion 3c (on the side of the straight portion 3b).

[0050] 13 and 14 are more detailed explanatory views of the assembly of the first nozzle 3 and the insulating member 42. Each figure shows the first nozzle 3 depicted in FIG. 10 as viewed from the U direction shown in the figure. 13, a partial notch V is formed in the bent portion 3c so that the protrusion T of the insulating member 42 can be dropped into the gap S. The protrusion T of the insulating member 42 is aligned with the notch V, and the insulating member 42 is moved toward the connecting portion 3d (the back side of the figure), whereby the protrusion T of the insulating member 42 is positioned in the gap S of the first nozzle 3.

[0051] Gap S is formed around linear portion 3b of first nozzle 3, allowing rotation of protrusion T of insulating member 42. In FIG. 13, after protrusion T of insulating member 42 is placed in gap S, insulating member 42 is rotated 90 degrees. At this time, the position of protrusion T of insulating member 42 moves from position 270, 90 in FIG. 13 to position 0, 180 in FIG. 14. Using such an assembly structure makes it possible to prevent insulating member 42 from falling off from first nozzle 3. By using such an insulating member 42, the heat transfer from the plasma generation chamber 21 to the first nozzle 3 is reduced.

[0052] Unlike the above-described embodiment, the insulating member 42 may not be used, and the first nozzle 3 may be made of a material with low thermal conductivity. 11 to 14 are merely examples, and other configurations may be adopted. The tip 3a of the first nozzle 3 may be formed of the insulating member 42, and the insulating member 42 may be screwed onto the first nozzle 3.

[0053] 15, the crucible 2 and the second nozzle 4 may be integrally molded to form a single member. Alternatively, 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.

[0054] In order to improve the efficiency of use 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 disposed over the entire area of ​​the crucible 2. In this case, the solid material 7 is either a porous body having a large mass with many holes formed therein through which the chlorine-containing gas passes, or is composed of an aggregate of fine powder- or pellet-shaped solid material. In order to release the aluminum-containing vapor from the vapor outlet 2a, the illustrated solid material 7 is configured so that when a chlorine-containing gas is introduced, the aluminum-containing vapor and a small amount of the chlorine-containing gas flow out through the vapor outlet 2a.

[0055] 17 and 18 show an embodiment of a method for producing aluminum-containing vapor. 17, first, a chlorine-containing gas is supplied to the crucible 2 in which the aluminum-containing solid material 7 is placed (step S1). Next, the crucible 2 is heated by the heater 5 until the temperature reaches a predetermined temperature (step S2). In process S1, aluminum chloride is generated as a reaction product between the aluminum-containing solid material 7 and the chlorine-containing gas. In process S2, the generated aluminum chloride is heated to a predetermined temperature to generate aluminum-containing vapor.

[0056] On the other hand, in the embodiment of Fig. 18, the order of the steps S1 and S2 is reversed compared to the embodiment of Fig. 17. As in the embodiment of Fig. 18, even if the step S2 is performed first and the crucible 2 is heated to a predetermined temperature by the heater 5, aluminum vapor can be generated as in Fig. 17. The reason for this is that if aluminum chloride is not produced in the process S1, aluminum-containing vapor will not be produced even if the temperature of the crucible 2 is heated to a predetermined temperature. Therefore, the order in which the processes S1 and S2 are performed does not matter.

[0057] Furthermore, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications are possible within the scope of the spirit thereof. The embodiments depicted in each drawing can be used alone or in combination with each other. [Explanation of symbols]

[0058] 1: Vaporizer 2: Crucible 2a: Steam outlet 2b: Chlorine-containing gas inlet 2c: Main body 2d: 1st end 2e: Second end 3: First nozzle 3a:Tip 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

1. a crucible having an aluminum-containing solid material disposed therein; a heater for heating the crucible, The crucible has a chlorine-containing gas inlet for introducing a chlorine-containing gas into the crucible; a vapor outlet 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; The vaporizer is characterized in that the chlorine-containing gas does not contain a dopant component in an ion implantation process.

2. 2. The carburetor of claim 1, wherein said solid material is pure aluminum.

3. A vaporizer as described in claim 1, wherein the chlorine-containing gas is chlorine gas.

4. The vaporizer of claim 1; A plasma generation chamber is provided inside to generate plasma, an ion source that emits the aluminum-containing vapor into the interior of the plasma generation chamber through a wall of the plasma generation chamber;

5. supplying a chlorine-containing gas that does not contain a dopant component in an ion implantation process to a crucible in which an aluminum-containing solid material is placed, and heating the crucible; The method for producing an aluminum-containing vapor includes producing an aluminum-containing vapor in the crucible.

Images