Vaporizer and ion source

Abstract

To provide a vaporizer having an optimum crucible shape for achieving a long life.SOLUTION: A vaporizer 1 includes a crucible 2 containing a solid material 7 and a heater 5 for heating a crucible 2. The crucible 2 include a wall W defining an internal space R, an inlet 2a connected to the wall W for discharging a reactive gas into the internal space R, and an outlet 2b connected to the wall W for discharging the reactive gas and vapor of a reaction product generated by the reaction between the reactive gas and the solid material 7 from the internal space R to the outside. The internal space R narrows toward at least one of the inlet 2a and the outlet 2b.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vaporizer and an ion source having the vaporizer. [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 create PN junctions.

[0004] When generating nitrogen ions, phosphorus ions, and boron ions, plasma is generally generated using gas as a raw material. On the other hand, when generating aluminum ions, since there is no suitable gas as a raw material, a solid material containing aluminum (including powder) is placed in the plasma generation chamber and sputtered to generate plasma containing aluminum ions.

[0005] Another method is to generate plasma containing aluminum ions using a vaporizer. In this method, a solid material containing aluminum is placed in the vaporizer's crucible, and vapor is generated from the solid material by raising the crucible temperature. The generated vapor is then supplied to a plasma generation chamber, where plasma containing aluminum ions is generated from the supplied vapor.

[0006] In response to this prior art, the inventors of the present application have proposed a new vaporizer described in Patent Document 1.

[0007] Unlike conventional vaporizers, this vaporizer supplies a reactive gas into a crucible. In the crucible, the reactive gas reacts with the solid material, generating a reaction product on the solid material. The generated reaction product is vaporized by heating the crucible to a high temperature and supplied to a plasma generation chamber. In the plasma generation chamber, plasma containing aluminum ions is generated from the supplied vapor. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent Publication No. 2023-154377 Summary of the Invention [Problem to be solved by the invention]

[0009] One of the key factors in improving productivity in the semiconductor device manufacturing process is to operate the vaporizer for a long period of time, i.e., to extend the vaporizer's lifespan. To extend the vaporizer's operating time, it is necessary to increase the size of the solid material placed in the crucible. However, simply increasing the size of the solid material may cause problems in the operation of the vaporizer. A primary object of the present invention is to provide a vaporizer having an optimum crucible shape for achieving a long life of the vaporizer, and an ion source equipped with the vaporizer. [Means for solving the problem]

[0010] The vaporizer is a crucible containing a solid material; a heater for heating the crucible; the crucible has a wall that forms an internal space, an inlet connected to the wall for discharging a reactive gas into the internal space, and an outlet connected to the wall for discharging the reactive gas and a vapor of a reaction product generated by the reaction between the solid material and the reactive gas from the internal space to the outside; The internal space narrows toward at least one of the inlet and the outlet.

[0011] By configuring the internal space of the crucible so that it narrows toward at least one of the inlet and outlet, a larger solid material can be placed in the internal space of the crucible without interfering with the operation of the vaporizer.

[0012] The vaporizer is a crucible for receiving the solid material; a heater for heating the crucible, the crucible having an inlet for receiving a reactive gas into the crucible; an outlet through which reactive gases and vapors are released from the crucible; a wall connecting the inlet and the outlet; the wall has a first portion, a second portion, and a third portion; the first section extends parallel to the inlet and the outlet, the second section connects the first section to the inlet, and the third section connects the first section to the outlet; At least the second section decreases in dimension toward the inlet or the third section decreases in dimension toward the outlet.

[0013] The wall of the crucible is divided into a first section, a second section, and a third section, and the dimensions of at least the second section decrease toward the inlet or the dimensions of the third section decrease toward the outlet, so that larger solid materials can be placed inside the crucible without interfering with the operation of the vaporizer.

[0014] The ion source is The vaporizer described above; a plasma generation chamber for generating plasma from the vapor supplied from the vaporizer; and an extraction electrode for extracting an ion beam from the plasma. [Effects of the Invention]

[0015] The internal space of the crucible is configured to narrow toward at least one of the inlet and outlet, or the wall of the crucible is divided into first, second, and third sections, and the dimensions of at least the second section decrease toward the inlet or the dimensions of the third section decrease toward the outlet, so that larger solid materials can be placed inside the crucible without interfering with the operation of the vaporizer. [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] A perspective view of an insulating member [Figure 4] An explanatory diagram of how to attach the insulating member to the first nozzle [Figure 5] An explanatory diagram of how to attach the insulating member to the first nozzle [Figure 6] Schematic cross-sectional view showing the configuration of a crucible in one embodiment. [Figure 7] Cross section of line AA shown in Figure 6 [Figure 8] FIG. 7 is a schematic cross-sectional view showing a comparative example to the embodiment of FIG. 6; [Figure 9] Schematic cross-sectional view showing the configuration of a crucible in another embodiment. [Figure 10] FIG. 10 is a schematic cross-sectional view showing a comparative example to the embodiment of FIG. [Figure 11] Schematic cross-sectional view showing the configuration of a crucible in another embodiment. [Figure 12] Schematic cross-sectional view showing the configuration of a crucible in another embodiment. [Figure 13] Schematic cross-sectional view showing the configuration of a crucible in another embodiment. [Figure 14] Schematic cross-sectional view showing the configuration of a crucible in another embodiment. [Figure 15] Schematic cross-sectional view showing the configuration of a crucible in another embodiment. [Figure 16] Schematic cross-sectional view showing the configuration of a crucible in another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] FIG. 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 16 heats a cathode 15. The heated cathode 15 emits ionization electrons into a plasma generation chamber 14. A reflector 17 is disposed opposite the cathode 15. The reflector 17 repels ionization electrons that approach the reflector 17 toward the cathode 15. An electromagnet (not shown) is disposed outside the plasma generation chamber 14. This electromagnet generates a magnetic field inside the plasma generation chamber 14 along the direction in which the cathode 15 and the reflecting electrode 17 face each other.

[0018] Vapor containing aluminum (aluminum-containing vapor) is supplied from the vaporizer 1 into the plasma generation chamber 14. In the plasma generation chamber 14, plasma P is generated from the aluminum-containing vapor. An ion beam IB containing aluminum ions is extracted by an extraction electrode E from an ion extraction port 23 of the plasma generation chamber 14. In FIG. 1, two annular extraction electrodes E having a hole in the center through which the ion beam IB passes are shown, but the number of extraction electrodes E is merely an example. In some embodiments, the number of extraction electrodes E may be more or less than two. The number of extraction electrodes E may be changed depending on the configuration of the ion source. The vaporizer 1 includes a crucible 2 in which an aluminum-containing solid material 7 (e.g., a solid material such as pure aluminum, aluminum nitride, or aluminum oxide, including powdered material) is placed.

[0019] The crucible 2 illustrated in Fig. 1 is a cylindrical member that is long in one direction. For example, the axis of the crucible 2 may extend along its longitudinal direction (for example, the Z-axis direction in Fig. 1). One longitudinal end of the crucible 2 is provided with an outlet 2b for supplying aluminum-containing vapor and a reactive gas to the plasma generation chamber 14. The other longitudinal end of the crucible 2 is provided with an inlet 2a for supplying a gas containing chlorine (chlorine-containing gas), which is a reactive gas, into the crucible 2. In some embodiments, the chlorine-containing gas is, for example, chlorine gas (Cl) or hydrogen chloride gas (HCl). It may also be a gas obtained by vaporizing a chlorine-containing dimethylaluminum chloride solution.

[0020] A first nozzle 3 is detachably attached to the crucible 2. In the configuration example of Fig. 1, a second nozzle 4 for supplying a reactive gas into the crucible 2 is integrally formed with the crucible 2. Various methods (for example, fitting and / or screwing) can be used to attach the first nozzle 3 to the crucible 2. The first nozzle 3 and the second nozzle 4 each have an elongated cylindrical shape. In some embodiments, the first nozzle 3, the second nozzle 4, and the crucible 2 are made of graphite. However, graphite is merely an example, and other materials may be used in some embodiments.

[0021] In FIG. 1, arrow J indicates the flow of chlorine-containing gas supplied to crucible 2. The chlorine-containing gas flows from gas supply source 11 through valve 12, passes through second nozzle 4, crucible 2, and first nozzle 3, and then enters plasma generation chamber 14. The chlorine-containing gas reacts with aluminum-containing solid material 7 heated to a high temperature. This reaction produces reaction products such as aluminum chloride (AlCl3). The produced reaction products are vaporized in high-temperature crucible 2. This vapor contains aluminum particles. The aluminum-containing vapor and chlorine-containing gas are supplied from crucible 2 to plasma generation chamber 14 via first nozzle 3.

[0022] 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. As a result, the ion beam current of the ion beam containing aluminum ions extracted from the ion source IS increases. 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.

[0023] 1 , the chlorine-containing gas may be supplied to the second nozzle 4 via a coupling member 9 fitted inside the second nozzle 4. For example, in some embodiments, the chlorine-containing gas may be supplied from a gas supply source 11 configured to supply the chlorine-containing gas. For example, a mass flow controller may be connected to a pipe 13 connecting the gas supply source 11 and the coupling member 9 to control the flow rate of the chlorine-containing gas. However, the specific configuration for the gas supply is not particularly limited as long as it can supply the chlorine-containing gas to the coupling member 9. In some embodiments, the crucible 2, the first nozzle 3, the second nozzle 4, and other components that serve as a flow path for the chlorine-containing gas may be formed from a corrosion-resistant carbon material.

[0024] The tip 3a of the first nozzle 3, located opposite the end attached to the crucible 2, protrudes into the plasma generation chamber 14. The tip 3a is provided with openings for supplying vapor in four orthogonal directions. This configuration of the openings for supplying vapor allows the aluminum-containing vapor to be diffused and supplied in multiple directions inside the plasma generation chamber 14. Not limited to the above embodiment, the tip 3a of the first nozzle 3 may have a single opening in the extending direction of the nozzle. In this case, the first nozzle 3 may be kept within the wall surface of the plasma generation chamber 14 without protruding into the plasma generation chamber 14. The plasma generation chamber 14 may be provided with a gas supply port 22 through which gases such as boron trifluoride, phosphine, and arsine are supplied in addition to the vapor supplied from the vaporizer 1.

[0025] 2 is a diagram showing an example of a more detailed configuration of the first nozzle 3 of the ion source IS shown in FIG. A flow path 3-4 indicates a flow path for a chlorine-containing gas and an aluminum-containing vapor. The flow path 3-4 communicates with an opening H at the tip 3a of the first nozzle 3. 2 and in the up-down direction. With this configuration of the openings H, the first nozzle 3 can supply the chlorine-containing gas and aluminum-containing vapor in four directions within the plasma generation chamber 14.

[0026] 1 and 2, the distal end 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 more than 4. Increasing the number of openings allows the aluminum-containing vapor to be supplied to the plasma generation chamber 14 from more directions, thereby achieving a more dispersed supply of gas within the plasma generation chamber 14.

[0027] Returning to Fig. 1, a heater 5 is disposed on the outer periphery of the crucible 2. This heater 5 is, for example, a coil heater or a sheet heater, but various heaters may also be used. A first heat shielding plate 6a for blocking heat radiation from the heater 5 is disposed around the outer periphery of the heater 5.

[0028] In some embodiments, the second nozzle 4 may have an enlarged diameter portion 4a. In some embodiments, a flange 8 may be provided for attaching the vaporizer 1 to an ion source flange 18. In FIG. 1, the ion source flange 18 supports components not shown, thereby indirectly supporting the plasma generation chamber 14 and other components such as the filament 16 and cathode 15 around the plasma generation chamber 14.

[0029] A coil spring 10 may be provided between the flange 8 and the large diameter portion 4a of the second nozzle 4. The coil spring 10 urges the vaporizer 1 against the side wall of the plasma generation chamber 14 to keep the space between the first nozzle 3 and the plasma generation chamber 14 airtight and to prevent the aluminum-containing vapor and / or chlorine-containing gas from leaking out from between the members. Furthermore, the elastic member that biases the vaporizer 1 against the side wall of the plasma generation chamber 14 is not limited to the coil spring 10, and other alternative means such as a leaf spring may be used.

[0030] In some embodiments, one or more gaskets (not shown) may be provided between the vaporizer 1 and the sidewall of the plasma generation chamber 14 to maintain an airtight seal between the first nozzle 3 and the plasma generation chamber 14. In some embodiments, a damper, for example a spring clip in the form of a snap ring, may be attached to the first nozzle 3 to prevent excessive pressure due to the elastic force of the coil spring 10 . In yet another embodiment, a damper, for example, 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 6a to prevent excessive pressure due to the elastic force of the coil spring 10. In some embodiments, one or all of one or more gaskets, snap rings, and / or spring clips may be provided. The gaskets, snap rings, and spring clips are exemplary only, and in other embodiments, different or additional structures may be used.

[0031] In some embodiments, only a portion of the interior of the crucible 2 may be filled with the solid material 7. For example, in some embodiments, the upper end of the solid material 7 may coincide with the lower end of the outlet 2b.

[0032] The above description is provided using the example of an IHC ion source, however, the IHC ion source is only one example embodiment and in other embodiments, other types of ion sources such as a Bernas ion source, a radio frequency inductively coupled plasma ion source, etc. may be used as the ion source IS.

[0033] As described above, heat transfer from the plasma generation chamber 14 to the end of the crucible 2 occurs near the plasma generation chamber 14, and accordingly, a large temperature difference occurs from one end of the crucible 2 to the other, which may make it difficult to achieve a stable vapor supply from the vaporizer 1 to the plasma generation chamber 14. In some embodiments, the vaporizer 1 can include an insulator 21 surrounding the first nozzle 3 that supplies the aluminum-containing vapor to the plasma generation chamber 14 . In some embodiments, the second heat shield 6b may be omitted and the vaporizer 1 may include an insulator 21. In some embodiments, the insulator 21 may be formed of alumina (Al2O3). In some embodiments, the insulator 21 may be formed of boron nitride (BN). However, the material of insulator 21 is not limited to these examples, and in some embodiments, other materials that provide thermal insulation may be used.

[0034] The insulator 21 can insulate the first nozzle 3 and its tip 3 a from the heat generated by the plasma generation chamber 14 . The insulator 21 may function to prevent heat from the plasma generation chamber 14 from heating the end of the crucible 2 near the first nozzle 3 and the plasma generation chamber 14 .

[0035] 2 is a diagram showing an example of a more detailed configuration of the first nozzle 3 of the ion source IS shown in FIG. A flow path 3-4 indicates a flow path for a chlorine-containing gas and an aluminum-containing vapor. The flow path 3-4 communicates with an opening H at the tip 3a of the first nozzle 3. 2 and in the up-down direction. The openings H enable the first nozzle 3 to supply the chlorine-containing gas and aluminum-containing vapor in four directions within the plasma generation chamber 14.

[0036] 1 and 2, the distal end 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 more than 4. Increasing the number of openings allows the aluminum-containing vapor to be supplied to the plasma generation chamber 14 from more directions, thereby achieving a more dispersed supply of gas within the plasma generation chamber 14.

[0037] The first nozzle 3 may have a first portion 3-1 including an annular groove G therein, a second portion 3-2 extending along a flow path 3-4, and a third portion 3-3 connecting the first portion 3-1 and the second portion 3-2. The flow path 3-4 connects the inside of the crucible 2 with the inside of the plasma generation chamber 14, and provides a path for the reactive gas and aluminum-containing vapor. The flow path 3-4 is connected to an opening H of the tip 3a of the first nozzle 3.

[0038] 2, the insulator 21 may be provided so as to cover at least a portion of the outer surface of the second portion 3-2 of the first nozzle 3, and may be in contact with the inner surface of the first portion 3-1. The insulator 21 may include a main body MB and protrusions Pr each extending radially outward from the main body MB of the insulator 21.

[0039] Figures 3-5 are diagrams illustrating an example of an insulator 21 according to some embodiments. Figure 3 is a perspective view of the insulator 21. Figure 4 shows the insulator 21 attached to the first nozzle 3 before rotation. Figure 5 shows the insulator 21 attached to the first nozzle 3 after rotation.

[0040] As shown in Figures 3-5, the insulator 21 may be composed of a generally cylindrical main body MB and a protrusion Pr that protrudes radially outward from the main body MB at a position along the main body MB that is closer to the crucible 2 than the plasma generation chamber 14 when the insulator 21 is attached to the first nozzle 3. In some embodiments, two protrusions Pr may be provided, as shown in Figures 3-5. However, this is merely an example, and in some embodiments, more than one protrusion Pr may be provided.

[0041] In some embodiments, the first portion 3-1 of the first nozzle 3 may have a slot S extending axially from the outer edge OE of the first portion 3-1 to the annular groove G (see FIG. 2). The insulator 21 is slid onto the first nozzle 3 in a configuration in which the protrusions Pr match the slots S (see FIG. 4) so ​​that the protrusions Pr slide within the slots S until they reach the annular groove G. Thereafter, the insulator 21 is rotated so that the protrusion Pr slides circumferentially in the annular groove G (see FIG. 5), and the insulator 21 is fixed to the first nozzle 3 so that the insulator 21 does not shift from the first nozzle 3.

[0042] For example, as shown in FIG. 4, the slots S may be provided at 90 degrees and 270 degrees, and to secure the insulator 21 onto the first nozzle 3, the insulator 21 may be rotated 90 degrees clockwise so that the protrusions Pr move from 90 degrees and 270 degrees in FIG. 4 to 0 degrees and 180 degrees in FIG. 5. In some embodiments, the annular groove G may be provided in two arc segments, one extending from 270 degrees to 0 degrees and the other extending from 90 degrees to 180 degrees. However, the configuration of the annular groove G is merely exemplary, and in some embodiments, the annular groove G may be an annular groove that extends 360 degrees around the first nozzle 3. In other embodiments, the arc segments may be provided between different circumferential angles, as long as the protrusions Pr of the insulator 21 can be rotated into position within the annular groove G to secure the insulator 21 on the first nozzle 3.

[0043] 6 is a schematic cross-sectional view of an example crucible 2 according to some embodiments. In FIG. 6, like reference numerals refer to like elements in FIGS. 1-5, and repeated descriptions thereof will be omitted for the sake of brevity.

[0044] Wall W, which defines the internal space R of crucible 2, is made up of a portion of crucible 2 and a portion of first nozzle 3. Wall W communicates with inlet 2a and outlet 2b in the longitudinal direction of crucible 2 (the Z-axis direction in the drawing). Crucible 2 has a cylindrical shape extending in one direction, but may also have a rectangular cylindrical shape. Crucible 2 has a length direction and a width direction that are perpendicular to each other. In the cross-sectional view of FIG. 6, the length direction of crucible 2 is the Z-axis direction, and the width direction of crucible 2 is the Y-axis direction.

[0045] A wall W that forms the internal space R of the crucible 2 is divided into three regions in the longitudinal direction (e.g., the Z-axis direction) of the crucible 2. In the first region W1, the wall W extends parallel to the direction connecting the inlet 2a and the outlet 2b (e.g., the Z-axis direction), and the width dimension of the wall W along the longitudinal direction of the crucible 2 (e.g., the dimension in the Y-axis direction) is constant. In the second region W2 adjacent to the first region W1, the width dimension of the wall W (e.g., the dimension in the Y-axis direction) decreases from the first region W1 toward the inlet 2a.

[0046] In a third region W3 adjacent to the first region W1, the width dimension of the wall W decreases from the first region W1 toward the outlet 2b. More specifically, the wall W changes linearly between the second region W2 and the third region W3. Due to this inclined structure, the width dimension of the wall W decreases from the first region W1 toward the inlet 2a or from the first region W1 toward the outlet 2b.

[0047] Fig. 7 is a cross-sectional view taken along line AA in Fig. 6. If the temperature of the crucible 2 is set to a temperature equal to or higher than the melting temperature of the solid material 7, there is a concern that the solid material 7 may flow into the inlet 2a or the outlet 2b. Therefore, as shown in Fig. 7, the position of the top surface of the solid material 7 is made lower than the bottom surface of the inlet 2a. Note that Fig. 7 only shows the outlet 2b side, but the same relationship applies to the inlet 2a side.

[0048] FIG. 8 shows a comparative example to the crucible 2 of FIGS. 6 and 7. In the crucible 2-1 of FIG. 8, the wall W includes only the first portion W1. When a solid material 7 having the same width as that shown in FIG. 6 is placed in the crucible 2-1 of FIG. 8, the dimensions of the solid material 7 are smaller than the dimensions of the solid material 7 that can be accommodated in the crucible 2 of FIG. 6. The configuration of the crucible 2 of FIG. 6 allows for a larger solid material 7 to be placed therein. As a result, the life of the vaporizer 1 can be extended.

[0049] 6, the dimensions of the solid material 7 that can be accommodated in the crucible 2 are smaller in the width direction (e.g., Y-axis direction) of the crucible 2 than the distance from the bottom of the crucible 2 to the inlet 2a and the outlet 2b. However, as shown in FIG. 9, the dimensions of the solid material 7 that can be accommodated in the crucible 2 may be larger in the width direction (e.g., Y-axis direction) of the crucible 2 than the distance from the bottom of the crucible 2 to the inlet 2a or the outlet 2b.

[0050] The intersection of the second portion W2 of the wall W with the first portion W1, and the intersection of the third portion W3 of the wall W with the first portion W1 restrict the movement of the aluminum-containing solid material 7 in the longitudinal direction (e.g., the Z-axis direction) within the crucible 2. In this way, the second portion W2 and the third portion W3 of the wall W restrict the movement of the solid material 7 in the longitudinal direction of the crucible 2 (e.g., the Z-axis direction), but even if the solid material 7 is arranged in such a large amount, the solid material 7 does not block the inlet 2a and the outlet 2b, so the vaporizer 1 can be operated without any problems. That is, in the crucible 2, a flow can be maintained in which reactive gas and vapor are blown into the crucible 2 from the inlet 2a, flow around to the top of the solid material 7, and then blown out from the outlet 2b.

[0051] FIG. 10 is a diagram showing a comparative example of the crucible 2 shown in FIG. 9. A solid material 7 having the same dimensions as that shown in FIG. 9 is placed in a crucible 2-1 in FIG. 10. The wall W of the crucible 2-1 in FIG. 10 has only the first portion W1, and therefore has no portion that restricts the movement of the solid material 7 in the longitudinal direction of the crucible 2 (e.g., the Z-axis direction). Therefore, during heating, the solid material 7 may move in the longitudinal direction within the crucible 2 and seal the inlet 2a and outlet 2b, which may interfere with the operation of the vaporizer 1.

[0052] In the crucible 2 shown in FIGS. 1, 6, 7, and 9, the second nozzle 4 and the crucible 2 are integrally formed. Alternatively, as shown in FIG. 11, the second nozzle 4 and the crucible 2 may be separate entities, and the second nozzle 4 may be attached to the crucible 2. In this configuration, the second nozzle 4 also serves as part of the crucible 2, and the wall W forming the internal space R of the crucible 2 includes part of the crucible 2, part of the first nozzle 3, and part of the second nozzle 4. In the wall W of the crucible 2 shown in FIGS. 1, 6, 7, 9, and 11, linear slopes SL are formed in the second region W2 and the third region W3. Other examples of such slopes SL include a curved shape as shown in FIG. 12 and a stepped shape as shown in FIG. 13.

[0053] The slope SL need not be straight, curved, or stepped, but may be any combination of these in some embodiments. The walls W of the crucible 2 in Figures 1, 6, 7, 9, and 11-13 have a symmetrical structure at the longitudinal ends of the crucible 2. However, in some embodiments, an asymmetrical structure may be used.

[0054] For example, as shown in Fig. 14, the wall W of the crucible 2 may have a first portion W1 and a second portion W2, but may not have a third portion W3. Even if the wall W has the third portion W3, the shapes of the wall W at the second portion W2 and the third portion W3 may be different. The wall W at the second portion W2 and the third portion W3 does not need to be inclined over the entire wall. For example, as shown in Fig. 15, an inclined structure may be adopted only on the lower side of the wall W, sandwiching the inlet 2a and the outlet 2b.

[0055] In some embodiments, the inlet 2a and the outlet 2b are arranged side by side along the longitudinal direction of the crucible 2. That is, in some embodiments, the inlet 2a and the outlet 2b are on the same axis. 16, the positions where they are arranged may be different in the width direction (for example, the Y-axis direction) of the crucible 2. The aluminum-containing solid material 7 may be in the form of a powder, pellets, or block. The blocks generally facilitate the placement of the aluminum-containing solid material 7 at a specific location.

[0056] This vaporizer 1 can also be used to produce other metal ions by replacing the aluminum-containing solid material 7 with titanium, nickel and / or their compounds. Additionally, the type of reactive gas can be changed.

[0057] Furthermore, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0058] 1. Vaporizer 2 Crucible 2a entrance 2b exit 5 Heater 7 Solid materials 14 Plasma generation chamber E Extraction electrode W wall W1 1st part W2 2nd section W3 3rd part R Interior space IS ion source

Claims

1. a crucible containing a solid material; a heater for heating the crucible; the crucible has a wall that forms an internal space, an inlet connected to the wall for discharging a reactive gas into the internal space, and an outlet connected to the wall for discharging the reactive gas and a vapor of a reaction product generated by the reaction between the solid material and the reactive gas from the internal space to the outside; A vaporizer, wherein the interior space narrows toward at least one of the inlet and the outlet.

2. 2. The carburetor of claim 1, wherein the interior space narrows toward both the inlet and the outlet.

3. The vaporizer according to claim 1 , wherein a portion of the wall has an inclined structure, thereby narrowing the internal space.

4. 2. The vaporizer of claim 1, wherein the direction of release of the reactive gas from the inlet coincides with the direction of release of the reactive gas and the vapor of the reaction product from the outlet.

5. 2. The vaporizer according to claim 1, wherein the internal space is symmetrical on the inlet side and the outlet side when viewed from the center of the internal space.

6. a crucible for receiving the solid material; a heater for heating the crucible, the crucible having an inlet for receiving a reactive gas into the crucible; an outlet through which reactive gases and vapors are released from the crucible; a wall connecting the inlet and the outlet; the wall has a first portion, a second portion, and a third portion; the first portion extends parallel to the inlet and the outlet, the second portion connects the first portion to the inlet, and the third portion connects the first portion to the outlet; A carburetor wherein at least the second section decreases in dimension toward the inlet or the third section decreases in dimension toward the outlet.

7. 7. The carburetor of claim 6, wherein the wall has the second portion tapered from the first portion toward the inlet.

8. 7. The carburetor of claim 6, wherein the wall has the third portion tapered from the first portion toward the outlet.

9. 8. The vaporizer of claim 7, wherein the wall has the third portion tapered from the first portion toward the outlet.

10. A vaporizer according to any one of claims 1 to 9; a plasma generation chamber for generating plasma from the vapor supplied from the vaporizer; an extraction electrode for extracting an ion beam from the plasma;

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