JP2001192293A - Source for molecular beam and molecular beam epitaxy device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently secure a filling amount of a molecular beam material even when a crucible is allowed to incline and to obtain stable strength of the molecular beam even when the amount of the molecular beam material is reduced. SOLUTION: In a molecular beam source cell 101, a crucible 102 having an inlet opening part 111 and a heater 103 which is attached to the crucible 102 and heats a molecular beam material filled in the crucible 102 to generate the molecular beam by evaporation and sublimation from the inlet opening part 111 are provided. The crucible 102 mentioned above is bent between a part 108 to be filled with the molecular beam material and the inlet opening part 111 so that the molecular beam material filled in the part 108 can be seen from the inlet opening part 11, and each sectional area in the horizontal direction of the part 108 to be filled with the molecular beam material is made nearly uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molecular beam source and a molecular beam epitaxy apparatus, and more particularly, to a method in which a molecular beam material is put in a molecular beam crystal growth (Molecular Beam Epitaxy or MBE) method, and is evaporated and sublimated by heat. The present invention relates to a molecular beam source and a molecular beam epitaxy apparatus that generate a molecular beam by causing the molecular beam to be generated.

[0002]

2. Description of the Related Art MBE
The method is a technique of generating a molecular beam by evaporating and sublimating a high-purity material, and growing the crystal on a GaAs substrate or the like in a high vacuum, and is widely used as a method for producing a semiconductor thin film constituting a compound semiconductor such as a semiconductor laser. It is a method used and researched and developed for further improvement.

An important matter in producing the semiconductor thin film is to reduce residual impurities in the vacuum chamber. To this end, improvements have been made to the exhaust system, chamber baking has been performed, and a good semiconductor thin film has been obtained. However, when the liquid nitrogen is removed from the shroud, the molecular gas source (hereinafter referred to as “molecular beam source cell” or (Sometimes simply referred to as a "cell"). The dropped deposits re-evaporate during the next crystal growth, increasing residual impurities in the vacuum chamber, deteriorating the quality of the semiconductor thin film, and also used for heating the material of the crucible of the molecular beam source cell and for measuring the temperature. There is a possibility that a trouble such as insulation failure may occur by getting into a thermocouple lead wire or the like.

For this reason, measures have been taken to incline the chamber so as to make it difficult for the adhering substances attached to the shroud and the like around the substrate to enter the cell even if it falls. However, with such a configuration, in the case of using crucibles 601 and 602 having a conventional structure (hereinafter sometimes simply referred to as containers) 601 and 602 shown in FIG. 10 or FIG. 11, a cell attached to an upper port has a larger inclination. Therefore, the amount of molecular beam material that can be filled in the crucibles 601 and 602 is reduced. Therefore, the number of maintenance operations for filling the material has increased, resulting in a decrease in the operation rate of the apparatus and an increase in product cost.

Further, in the case where the inclination angle of the chamber is large and the port mounting angle is such that the opening of the cell is lower than horizontal, the crucible 60 having the conventional structure shown in FIG. 10 or FIG.
When 1 · 602 is used, a molten molecular beam material cannot be used, and the usable material is limited to a sublimation type material.
Japanese Unexamined Patent Publication No. Hei 11-504613 discloses a crucible 603 having a single unitary structure as shown in FIG. With this structure, for example, a molten molecular beam material can be used even when the cell is installed horizontally.

[0006] As described above, when the chamber is tilted in order to prevent the deposits attached to the shroud or the like from falling, the amount of molecular beam material that can be filled in the crucible decreases as the cell attached to the upper port decreases the material. There is a problem that the number of maintenance times for filling increases, the machine time decreases, and the product cost increases. Further, when the cell is installed substantially horizontally using the crucible having the conventional structure shown in FIG. 12, the molecular beam material is consumed, the liquid level is lowered, and the evaporation area of the material is changed, that is, the molecular beam intensity, in other words, The flux intensity changes. Usually, the molecular beam intensity is adjusted by correcting the heater temperature by measuring periodically, but when the evaporation area is likely to change in the structure, it is necessary to frequently perform the measurement and correction,
This leads to problems such as a decrease in equipment operation rate and an increase in product cost.

Further, as a conventional molecular beam source cell, FIG.
As shown in FIG. 3, the shroud 6 around the substrate holder 642
Some are attached to the inclined vacuum chamber 641 so that the deposits falling from the 43 do not enter the inside. As shown in FIG. 14, this molecular beam source cell 644A,
Each of 644B and 644C has a crucible for accommodating the molecular beam material 646, that is, containers 645A, 645B, and 645C.

By the way, the molecular beam source cells 644A, 6
In 44B and 644C, the molecular beam source cells 644A and 644 are used.
Since the B and 644C themselves are inclined, the container 645B has a smaller filling amount of the molecular beam material 646 than the container 645C, and the container 645A has a smaller molecular beam material 646 than the container 645B having the smaller filling amount. Is low. That is, the containers 645A, 645B, 645
There is a problem in that the amount of the molecular beam material 646 that can be filled in C decreases as the cells become higher. Also,
Deposits attached to the shroud 643 above the molecular beam source cells 644A, 644B, 644C fall into the molecular beam source cells 644A, 644B, 644C, and impurities are mixed in the molecular beam material 646. The impurities re-evaporated at the time of crystal growth contaminate the inside of the vacuum chamber 641 and degrade the quality of the crystal-grown thin film.

Further, such a molecular beam source cell 644A,
In a molecular beam epitaxy apparatus (hereinafter sometimes simply referred to as an MBE apparatus or a molecular beam crystal growth apparatus) 651 including 644B and 644C, molecular beam source cells 644A and 644 are provided.
Since the filling amount of the molecular beam material 646 in B and 644C is small, it is necessary to frequently replenish the molecular beam material 646, and the number of maintenances accompanying the replenishment of the molecular beam material 646 increases. This maintenance is performed by the MBE device 65.
After stopping the operation, the inside of the vacuum chamber 641 is returned to normal pressure, and then the molecular beam material 646 is put in the containers 645A, 645B, and 645C. It takes a considerable date and time to make As described above, since the number of times of maintenance requiring a considerable date and time increases, the operating rate of the MBE apparatus 651 decreases significantly, and there is a problem that the manufacturing cost of the semiconductor thin film increases.

Therefore, one of the objects of the present invention is to provide a molecular beam source capable of increasing the filling amount of the molecular beam material and preventing contamination of the molecular beam material. Another object of the present invention is to provide a molecular beam epitaxy apparatus having such a molecular beam source, which can reduce the number of maintenance operations, reduce the manufacturing cost of a semiconductor thin film, and improve the yield.

[0011]

In order to achieve the above object, a molecular beam source according to the present invention comprises a crucible having an inlet opening, and the crucible is filled inside as viewed from the inlet opening. It is characterized in that the molecular beam material is bent so that it cannot be seen.

According to the molecular beam source having the above structure, the crucible (container) is filled with a molecular beam material. This crucible,
The molecular beam is bent so that the molecular beam material cannot be seen from the entrance opening (which is also an opening that emits toward the substrate). Thus, since the crucible is bent so that the molecular beam material cannot be seen from the entrance opening, impurities entering from the entrance opening adhere to the molecular beam material accommodated in the bottom of the crucible. Hateful. Therefore, it is possible to prevent the impurities from contaminating the molecular beam material.

Even if the inlet opening is inclined, the crucible is bent so that the molecular beam material cannot be seen from the inlet opening, so that the bottom for accommodating the inlet molecular beam material does not tilt. Therefore, the filling amount of the molecular beam material in the crucible can be increased.

Further, the present invention provides a crucible having an entrance opening, and a molecular beam material mounted on the crucible and filled in the crucible is heated and evaporated and sublimated from the entrance opening to generate a molecular beam. A crucible is bent between a portion for filling the molecular beam material and the entrance opening so that the molecular beam material to be filled is not visible from the entrance opening, and To provide a molecular beam source in which each horizontal cross-sectional area of a portion filled with is substantially uniform.

That is, in the molecular beam source according to the present invention, the whole shape of the crucible is bent so that the molecular beam material filled in the bottom from the inlet opening of the crucible cannot be seen, and the shape of the material-filled portion is material. The evaporation surface area is made substantially uniform so as not to change with the amount of the material, thereby making it possible to secure a sufficient amount of the molecular beam material even when the crucible is inclined, and to reduce the molecular beam material. In addition, stable molecular beam intensity can be obtained.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a molecular beam source and a molecular beam epitaxy apparatus including the same according to the present invention will be described in detail with reference to the illustrated embodiments. Note that the present invention is not limited by this.

(1) In the molecular beam source cell as the molecular beam source according to one embodiment of the present invention, the opening surface of the entrance opening of the molecular beam source cell itself is oriented in the horizontal direction or below the horizontal direction. It is characterized by:

According to the molecular beam source cell of the above embodiment,
Since the opening surface of the molecular beam source cell itself is oriented in the horizontal direction or below the horizontal direction, impurities falling from above do not enter the molecular beam source cell. As a result, impurities do not adhere to the molecular beam material in the container serving as the crucible, and contamination of the molecular beam material can be more reliably prevented.

In one embodiment, the molecular beam source cell has at least two heaters, a first heater for evaporating the molecular beam material and a second heater for controlling the amount of molecular beam generated from the molecular beam material. It is characterized by having.

In the molecular beam source cell according to the embodiment, the molecular beam material is evaporated by the first heater and the amount of the molecular beam generated from the molecular beam material is controlled by the second heater. Regardless of the shape, the amount of molecular beam can be controlled with good reproducibility.

Further, when controlling the amount of the molecular beam with good reproducibility, the shape of the container for containing the molecular beam material can be freely set because it does not depend on the shape of the molecular beam material.
That is, the degree of freedom of the shape of the container is improved.

Further, a molecular beam epitaxy apparatus of one embodiment, that is, a molecular beam crystal growing apparatus is characterized by having the above-mentioned molecular beam source cell.

The molecular beam crystal growing apparatus of the above embodiment is
By using the above-mentioned molecular beam source cell, the filling amount of the molecular beam material in the container can be increased, so that the number of times of replenishment of the molecular beam material is reduced, and the number of maintenances accompanying the replenishment can be reduced. As a result, the number of maintenances that require a considerable amount of time is reduced, so that the operation rate of the apparatus is improved and the productivity is improved. Therefore, it is possible to reduce the manufacturing cost of a thin film manufactured by this molecular beam crystal growth apparatus.

Further, since the contamination of the molecular beam material can be prevented, the molecular beam generated from the molecular beam material can be kept clean. Therefore, crystal growth is not performed by the contaminated molecular beam, and a thin film having good film quality is formed. As a result, the yield can be improved.

Further, since the amount of molecular beams generated from the molecular beam material can be controlled with good reproducibility, the reproducibility of crystal growth can be improved, and the yield can be further improved.

(2) Further, in a molecular beam epitaxy apparatus having a tilt type chamber, even when the molecular beam source according to the present invention is attached to the upper port, a large amount of molten molecular beam material can be filled, and material filling can be performed. Can be lengthened. Therefore, it is possible to improve the device operation rate. In addition, since the evaporation area does not change even when the molecular beam material is consumed and the liquid level is lowered, it is not necessary to frequently perform the molecular beam intensity correction, that is, the flux correction, and it is possible to improve the operation rate of the apparatus. .

As a specific form of the molecular beam source according to the present invention, the crucible is formed into a cylindrical shape (more preferably, a cylindrical shape), and the material filling portion of the crucible and the direction determining portion of the molecular beam, that is, the crucible are formed. The central axis of the two types of cylindrical portions, that is, the portion between the inlet opening and the material filling portion, is coplanar, and the angle between the two axes is 30 ° or more and 150 ° or less. It can be realized, and the material filling amount can be increased.

In the molecular beam source according to the present invention, when the heater is provided at least in a portion of the crucible filled with the molecular beam material and a ceiling portion almost directly above the portion, the ceiling portion is provided. Is a place where the molten material easily flies and adheres, so that the adhesion of the material can be effectively prevented. Of course, if the heater is arranged so as to cover substantially the entire crucible, the entire crucible can be kept at a high temperature, and it is possible to prevent the molecular beam material from adhering and depositing without being able to re-evaporate. It is more preferable because it is possible.

Further, it is preferable that the molecular beam source according to the present invention includes one system of heaters, and the heaters are arranged so that the temperature of the other portion is higher than the temperature of the material-filled portion. Furthermore, it has at least two systems of heater parts that can be controlled independently, and each heater part is divided into a material-filled part and other parts, and compared with the temperature of the material-filled part. When the temperature of other parts is increased, the molecular beam material hardly adheres to the inner wall surface of the crucible, and the flux intensity is easy to control, even though the molecular beam material is not visible from the entrance opening of the crucible. Is preferable.

In the molecular beam source of the present invention, when a water cooling mechanism, specifically, a water cooling jacket is arranged outside the heater,
Although most of the high-temperature portions such as the heater are not covered with the shroud, the temperature of the port portion of the apparatus and the vacuum vessel portion of the molecular beam source does not rise and the degree of vacuum does not deteriorate.

According to another aspect of the present invention, there is provided (a) a crucible having an inlet opening, and a molecular beam material mounted on the crucible and filled in the crucible is heated and evaporated from the inlet opening. A heater for generating a molecular beam by sublimation, wherein a crucible is provided between the portion for filling the molecular beam material and the entrance opening so that the molecular beam material to be filled is not visible from the entrance opening. A molecular beam source having a substantially uniform horizontal cross-sectional area at a portion where the molecular beam material is filled, (b) a vacuum chamber supporting the molecular beam source, and (c) an inner wall of the vacuum chamber. (D) a shroud provided along
There is provided a molecular beam epitaxy apparatus including a substrate holder provided in the shroud so as to face an inlet opening of the crucible of the molecular beam source.

Further, when the molecular beam epitaxy apparatus is provided with two or more molecular beam source portions, it is possible to increase the amount of the molecular beam material even in a molecular beam epitaxy apparatus having a tilted chamber, In addition, even if the attachment of the shroud falls, it is possible to prevent the trouble from entering the molecular beam source cell, so that the operation rate of the apparatus can be improved. Also, it is possible to prevent the adhering matter from entering the crucible at the time of film formation to deteriorate the film quality of the semiconductor thin film,
Product yield is improved.

(3) Several embodiments will be specifically described below. (First Embodiment) FIG. 1 is a schematic sectional view of an MBE apparatus as a molecular beam epitaxy apparatus according to a first embodiment of the present invention. As shown in FIG. 1, the MBE apparatus 13 includes a vacuum chamber 10 installed at an angle to the horizontal direction, a substrate holder 11 housed in the vacuum chamber 10,
A molecular beam source cell 1A, 1B, 1C is provided in the vacuum chamber 1 so as to face the substrate holder 11. A shroud 12 is attached to the inner wall of the vacuum chamber 1.

As shown in FIG. 2, the molecular beam source cell 1B includes a molecular beam material 7 accommodated in the bottom 2a when viewed from the tip 5a as an opening for emitting a molecular beam toward the substrate 6.
Crucible 2 as a container bent so as not to be seen, a bent bottomed cylindrical main body 5 accommodating this crucible 2, and first and second heaters arranged between main body 5 and crucible 2 3,
4 is provided. The first heater 3 is provided at the bottom 2 a of the crucible 2.
, While the second heater is disposed around the tip 2 b of the crucible 2. Also, the bottom 2 of the crucible 2
a, thermocouples 8, 9 for temperature detection are attached to the tip 2b.

The opening 1 of the molecular beam source cell 1B itself is used.
6 is formed at the tip 5a of the main body 5 on the substrate 6 side.
The upper portion 17 of the tip 5a extends longer toward the substrate 6 than the tip 2b of the crucible 2, and the lower portion 18 of the tip 5a extends slightly longer toward the substrate 6 than the tip 2b of the crucible 2. ing. Also, the upper part 1 of the tip 5a
7, a plane including the tips 19 and 20 of the lower portion 18, that is, the opening surface 15 is oriented in the horizontal direction. However, the opening surface 15 may face downward from the horizontal direction. Although only the molecular beam source cell 1B has been described in detail with reference to FIG. 2, the molecular beam source cells 1A and 1C shown in FIG. Although the direction of the surface is different, other configurations are the same. Molecular beam source cell 1
In each of A, 1B, and 1C, the direction of the opening surfaces 65, 15, and 75 is horizontal or downward.

The molecular beam source cells 1A, 1B, 1C having the above configuration
Then, at the time of crystal growth, the molecular beam material 7 is evaporated to generate a molecular beam in the first heater 3, and the amount of the molecular beam is controlled by the second heater 4 so that the molecular beam is
The light is emitted from the tip portion 5 a toward the substrate 6 to grow a crystal on the substrate 6. At this time, if liquid nitrogen is removed from the shroud 12, the attached matter which is an impurity attached to, for example, the shroud 12 other than the substrate 6 is peeled off and falls, but the molecular beam material 7 cannot be seen from the tip 5 a. Since the crucible 2 is bent as described above, the adhering matter entering through the opening 16 of the tip 5a does not easily adhere to the molecular beam material 7 stored in the bottom 2a of the crucible 2. Therefore, contamination of the molecular beam material 7 can be prevented.

Further, even if the tip 5a is inclined, the crucible 2 is held so that the molecular beam material 7 cannot be seen from the tip 5a.
Are bent, so that the bottom 2a for accommodating the molecular beam material 7 is formed.
Does not lean. Therefore, the filling amount of the molecular beam material 7 in the crucible 2 can be increased. Specifically, the amount of the molecular beam material 46 of the conventional containers 45A, 45B, and 45C shown in FIG. 6 was about 10 cc, whereas the molecular beam material 7 was 60 cc or more in the crucible 2 shown in FIG. You can enter.

The molecular beam source cells 1A, 1B, 1C
Since the opening surfaces 65, 15, and 75 of the self are oriented in the horizontal direction or the lower side than the horizontal direction, even if the attached matter which is an impurity attached to the shroud 12 or the like peels off during the crystal growth, it falls. The attached matter does not enter the molecular beam source cells 1A, 1B, 1C, and the attached matter does not enter the crucible 2 in the molecular beam source cells 1A, 1B, 1C. Therefore, the above crucible 2
Adherents as impurities do not adhere to the molecular beam material 7 therein, and the contamination of the molecular beam material 7 can be more reliably prevented.
Further, since the attached matter of the shroud 12 does not enter the molecular beam source cells 1A, 1B, 1C, the attached matter is the first and the second.
Troubles such as poor insulation caused by entering the lead wires of the second heaters 3 and 4 and the thermocouples 8 and 9 can be prevented.

Further, a first method for evaporating the molecular beam material 7 is described below.
Since the heater 3 and the second heater 4 for controlling the amount of the molecular beam generated from the molecular beam material 7 are provided, the amount of the molecular beam can be controlled with good reproducibility regardless of the shape of the molecular beam material 7. . At this time, since the shape of the molecular beam material 7 does not need to be limited, the shape of the crucible 2 containing the molecular beam material 7 can be freely set. That is, the degree of freedom of the shape of the crucible 2 is improved.

Further, such a molecular beam source cell 1A, 1
In the MBE apparatus 13 equipped with B and 1C, the number of times of replenishment of the molecular beam crystal material 7 is reduced to 1/6 or less as compared with the conventional case,
The number of maintenance operations accompanying the replenishment is also reduced. Therefore, the number of maintenances that require a considerable amount of time is reduced, so that the operation rate of the MBE apparatus 13 is improved, and the productivity is improved. Therefore, the manufacturing cost of the semiconductor thin film by the MBE device 13 can be reduced. Specifically, the manufacturing cost can be reduced to 1/4 or less as compared with the related art.

Further, in the MBE apparatus 13, since the contamination of the molecular beam material 7 in the molecular beam source cells 1A, 1B, 1C can be prevented, crystal growth is not performed on the contaminated molecular beam. Therefore, a thin film having good film quality is formed, and the yield can be improved.

Further, the MBE apparatus 13 includes the first heater 3 for evaporating the molecular beam material 7 and the second heater 4 for controlling the amount of molecular beam generated from the molecular beam material 7. The instability of the molecular dose due to a decrease in the molecular beam material 7 is eliminated, and the amount of molecular beams generated from the molecular beam material 7 can be controlled with good reproducibility. Therefore, the reproducibility of crystal growth is improved, and the yield can be further improved. Specifically, the yield was improved by about 30% as compared with the conventional case.

In the MBE apparatus 13, since the molecular beam source cells 1A, 1B, and 1C can be attached to the side surface of the vacuum chamber 10, the degree of freedom in the layout of the molecular beam source cells 1A, 1B, and 1C is improved. I have. In addition, when the molecular beam material 7 is filled, there is no need to work in a narrow space below the MBE device 13, so that workability is good.

In the above embodiment, the molecular beam source cell 1
The opening surface 15 of B itself is the tip 1 of the tip 5 a of the main body 5.
9 and 20, but the tip 2b of the crucible 2
May be included. That is, the opening of the molecular beam source cell itself may be formed in the main body or in the crucible. Also, regarding the molecular beam source cells 1A and 1C,
The opening surfaces of the molecular beam source cells 1A and 1C themselves may include the tip of the tip of the crucible.

In the above embodiment, the molecular beam source cell 1
Although the opening surfaces 65, 15, and 75 of A, 1B, and 1C themselves face the horizontal direction or the lower side than the horizontal direction, it is more preferable that they face the lower side than the horizontal direction.

In the above embodiment, the main body 5 is
However, the main body may be integrated with the crucible.

(Second Embodiment) FIG. 3 is a schematic sectional view of an MBE apparatus as a molecular beam crystal growth apparatus according to a second embodiment of the present invention. As shown in FIG.
Is a vacuum chamber 3 installed parallel to the horizontal direction.
0, the molecular beam source cells 21A, 21B, 21C arranged on the right side of the vacuum chamber 30 in the drawing, and the molecular beam source 2
Vacuum chamber 3 so as to face 1A, 21B, 21C
And a substrate holder 31 housed in the housing. A shroud 32 is provided on the inner wall of the vacuum chamber 30.
Is installed.

As shown in FIG. 4, the molecular beam source cell 21A has a molecular beam material 27 housed in the bottom 22a when viewed from the tip 25a as an opening for emitting a molecular beam toward the substrate 26. A crucible 22 serving as a container bent so as to be invisible, a bent bottomed cylindrical main body 25 accommodating the crucible 22, and first and second heaters 23 disposed between the main body 25 and the crucible 22 , 24. The first heater 23 is arranged around the bottom 22 a of the crucible 22, while the second heater 24 is arranged around the tip 22 b of the crucible 22. Further, thermocouples 28 and 29 for temperature detection are attached to the bottom portion 22a and the tip portion 22b of the crucible 22.

The opening 36 of the molecular beam source cell 21A itself is formed at the front end 25a of the main body 25 on the substrate 26 side. Upper part 37 and lower part 38 of this tip 25a
Extends slightly longer toward the substrate 26 than the tip portion 22b of the crucible 22. Also, the upper part 3 of the tip part 25a
7, a plane including the distal ends 39 and 40 of the lower portion 38, that is, the opening surface 35 faces downward from the horizontal direction. However,
This opening surface 35 may be oriented in the horizontal direction. Although only the molecular beam source cell 21A has been described in detail with reference to FIG. 4, the molecular beam source cells 21B and 21C shown in FIG. Although the direction of the surface is different, other configurations are the same. Each of the molecular beam source cells 21A, 21B, and 21C has an opening surface 3
The directions of 5, 85, 95 are horizontal or downward.

The molecular beam source cells 21A, 21B,
21C and the MBE device 33 comprising each
The same effects as those of the molecular beam source cell and the MBE device of the embodiment are obtained.

Further, since the crucible 22 is bent at a substantially right angle so that the molecular beam material 27 accommodated in the bottom portion 22a cannot be seen from the distal end portion 25a from which the molecular beam is emitted, the attachment of the shroud 32, etc. Impurities in the opening 36 of the tip 25a.
, The impurities hardly adhere to the molecular beam material 27 on the bottom 22a. Therefore, contamination of the molecular beam material 27 in the crucible 22 can be prevented very reliably.

In the above embodiment, the molecular beam source cell 2
Although the opening surface 35 of 1A itself includes the distal ends 39 and 40 of the distal end portion 25a of the main body 25, it may include the distal end of the distal end portion 22b of the crucible 22. That is, the opening of the molecular beam source cell itself may be formed in the main body or in the crucible. In addition, molecular beam source cells 21B and 21C
Also, the opening surfaces of the molecular beam source cells 21B and 21C may include the tip of the tip of the crucible.

In the above embodiment, the molecular beam source cell 2
Although the opening surfaces 35, 85, 95 of 1A, 21B, 21C themselves face the horizontal direction or lower than the horizontal direction, it is more preferable that they face lower than the horizontal direction.

In the above embodiment, the main body 25 is separate from the crucible 22, but the main body may be integral with the crucible.

As is clear from the above, the molecular beam source of the present invention includes a crucible having an inlet opening, and the crucible does not show the molecular beam material filled therein when viewed from the inlet opening. As a result, the impurities entering from the inlet opening hardly adhere to the molecular beam material filled in the crucible. Therefore, it is possible to prevent the impurities from contaminating the molecular beam material.

In the molecular beam source cell according to one embodiment, the crucible is bent so that the molecular beam material cannot be seen from the entrance opening even if the entrance opening is inclined, so that the molecular beam material is accommodated therein. The bottom does not tilt, and the filling amount of the molecular beam material in the crucible can be increased.

In the molecular beam source cell of one embodiment, since the opening surface of the entrance opening of the molecular beam source cell itself is oriented in the horizontal direction or lower than the horizontal direction, impurities falling from above are not affected by the molecular beam. The contamination of the molecular beam material can be more reliably prevented without entering the source cell.

In the molecular beam source cell of one embodiment, the molecular beam material is evaporated by the first heater and the amount of the molecular beam generated from the molecular beam material is controlled by the second heater. Regardless, the amount of molecular beam can be controlled with good reproducibility. At this time, since the shape of the molecular beam material does not depend on the shape, the degree of freedom of the shape of the container accommodating the molecular beam material is improved.

In the molecular beam crystal growth apparatus according to one embodiment, by providing the above-mentioned molecular beam source cell, the filling amount of the molecular beam material can be increased. The operation rate of the device can be improved, and the productivity can be improved. Therefore, the manufacturing cost of the semiconductor thin film manufactured by the molecular beam crystal growth apparatus can be reduced.

In the molecular beam crystal growing apparatus of one embodiment, since the molecular beam source cell is provided, the contamination of the molecular beam material can be prevented, so that the crystal growth is not performed by the contaminated molecular beam, and the film quality is good. A thin film can be formed. Therefore, the yield can be improved.

In the molecular beam crystal growing apparatus according to one embodiment, the amount of molecular beams generated from the molecular beam material can be controlled with good reproducibility by providing the above-mentioned molecular beam source cell, so that the reproducibility of crystal growth can be improved. . As a result, the yield can be further improved.

(4) Some embodiments will be described below more specifically. (Third Embodiment) FIG. 5 is an explanatory view of the configuration of a third embodiment of the molecular beam source according to the present invention. In FIG. 5, a molecular beam source cell (corresponding to the molecular beam source of the present invention) 10 of the third embodiment is shown.
Reference numeral 1 denotes a crucible 102 filled with a molecular beam material 106 (for example, gallium), a heater 103, a thermocouple 104, and a reflector 1
05, and a water-cooling jacket 107 is provided on an outer wall of a container (hereinafter, referred to as a vacuum container) 110 for holding a vacuum around the crucible 102. The crucible 102 is PBN as an example.
(Pyrolytic boron nitride), the overall shape of the crucible is an L-shape with a cylinder that extends upward as shown in the figure and is bent horizontally (at 90 °) in the middle, and one side (lower side) is sealed Have been.

In the portion extending upward, the molecular beam material 106
Is formed in the other horizontal portion, and a molecular beam shape determining portion 109 (between the entrance opening 111 and the material filling portion 108) that is opened and determines the shape of the molecular beam is formed in the other horizontal portion. It is configured.

The heater 103 is helically disposed so as to cover substantially the entire material filling portion 108 and the molecular beam shape determining portion 109. The interval between the heaters 103 is compared with the material-filled portion 108 and the molecular beam shape determining portion
Are arranged to be denser. The heaters of the respective portions are connected in series in one system, and the temperature of the molecular beam shape determining portion 109 becomes higher than that of the material filling portion 108 by flowing an electric current.

FIG. 6 shows a molecular beam source cell 101 according to the third embodiment.
FIG. 1 is an explanatory diagram showing a schematic configuration of an MBE apparatus (molecular beam epitaxy apparatus) 201 using a device. In FIG. 6, the MBE device 20
1 includes a molecular beam source cell 202, a substrate holder 203 provided with a substrate rotating / heating mechanism, and a shroud 204. The crucible entrance opening 205 of the molecular beam source cell 202 is a substrate holder 2
The molecular beam is set so as to face the center of 03 and enter at an angle of 25 ° with respect to the normal direction of the substrate holder 203 as an example. In the third embodiment, the molecular beam source cell 202 of the MBE apparatus 201 is installed so that the rotation axis of the substrate holder 203 is horizontal.

In such a configuration, the molecular beam source cell 202 has a molten molecular beam material despite the crucible inlet opening 205 of the molecular beam source cell 202 attached to the uppermost cell port being directed downward. 100 cc or more.

On the other hand, when the crucible having the conventional structure shown in FIG. 12 is used, the filling amount is about 1 cc, the filling amount of the molecular beam source cell 202 of the third embodiment is about 100 times, and the material filling cycle is 50 times. The product cost can be reduced to half or less, and the product cost can be reduced to half or less. Further, when the conventional structure shown in FIG. 12 is used, as the material is consumed and the liquid level decreases, the evaporation area decreases. Therefore, when the heater temperature is constant, the flux intensity decreases, and it is necessary to always correct the heater temperature in order to obtain a constant flux intensity. Usually, it is necessary to perform the flux correction after growing several times. Molecular beam source cell 2 of third embodiment
When 02 is used, even if the material is consumed and the liquid level is lowered, the evaporation area does not change, so that the heater temperature is constant and the flux intensity is substantially constant. Therefore, it is possible to lengthen the interval at which flux correction is performed, and it is possible to improve the operation rate of the apparatus.

Further, since the entrance opening 205 of the crucible of the molecular beam source cell 202 faces downward from the horizontal, even if the adhered substance of the shroud 201 falls, it may fall into the molecular beam source cell 202. Without the heater 103 or the thermocouple 10
4 can prevent a decrease in cell reliability due to insulation failure. In addition, it is possible to prevent deterioration of the film quality of the semiconductor thin film due to deposits entering the crucible during film formation.

In the third embodiment, the heater 103 is connected to the crucible 1
02 is disposed so as to cover almost the entirety of the crucible 1
In the case where there is a portion where the heater 103 is not provided in the portion 02, the temperature of the portion decreases, so that the molecular beam material cannot be re-evaporated and adheres and deposits. Therefore, heater 1
03 is desirably disposed so as to cover almost the entire crucible 102.

In the molecular beam source according to the present invention, most of the high-temperature portions such as the heater 103 are not covered with the shroud 204 of the apparatus. Therefore, the ports of the apparatus and the vacuum vessel of the molecular beam source are heated to a high temperature. Easy to be. Since a high temperature of the vacuum vessel affects the degree of vacuum, a water-cooling jacket 107 is provided as in the third embodiment to prevent the temperature of the port portion of the apparatus and the vacuum vessel portion of the molecular beam source from rising. desirable. In the present embodiment, the water cooling jacket 107 is provided outside the vacuum vessel, but the same effect can be obtained when a water cooling mechanism is provided outside the heater inside the vacuum vessel. In the third embodiment, the angle between the molecular beam shape determining portion 109 and the material filling portion 108 of the crucible 102 is 9 as an example.
Although set to 0 °, a similar effect can be obtained in the range of 30 ° to 150 °.

(Fourth Embodiment) FIG. 7 shows a molecular beam source cell having the same structure as that of the molecular beam source cell 101 of the third embodiment.
FIG. 2 is a schematic configuration explanatory view when the electronic device is attached to a BE device 301. In FIG. 7, an MBE apparatus 301 includes a molecular beam source cell 302 and a substrate holder 30 having a substrate rotating / heating mechanism.
3 and a shroud 304, the opening of the crucible 302 is directed to the center of the substrate holder 303, and the molecular beam is set to be incident at an angle of 25 ° with respect to the normal direction of the substrate holder 303, for example. The MBE apparatus 301 is installed so that the rotation axis of the substrate holder 303 forms an angle of, for example, 65 ° from the vertical.

The molecular beam source cell 302 includes an MBE device 301.
It is attached to the horizontal port of this, and according to this configuration,
250 cc or more of the molten molecular material can be filled.
When the conventional crucible shown in FIG. 12 is used, the filling amount is 20 cc, and the filling amount of the molecular beam source cell 302 of the fourth embodiment is about 10 times as compared with this.
The material filling cycle can be extended 5 times or more, and the product cost can be reduced to 2/3 or less.

Further, when the conventional crucible shown in FIG. 12 is used, the evaporation area becomes smaller as the material is consumed and the liquid level decreases, so that the flux intensity decreases when the heater temperature is constant. . Therefore, it is necessary to always correct the heater temperature in order to obtain a constant flux intensity. Usually, this flux correction needs to be performed after several growths. When the molecular beam source cell 302 of the fourth embodiment is used, the evaporation area does not change even if the material is consumed and the liquid level decreases, so that the heater temperature is constant and the flux intensity is substantially constant. Therefore, it is possible to lengthen the interval at which flux correction is performed, and it is possible to improve the operation rate of the apparatus.

Further, when the conventional crucible shown in FIG. 12 is used, there is a disadvantage that the film thickness distribution at the position of the substrate holder 303 changes because the shape of the molecular beam changes depending on the amount of the material. In the fourth embodiment, the angle between the molecular beam shape determining portion 109 of the crucible 102 and the material filling portion 108 is set to 90 ° as an example, but the same effect can be obtained if it is in the range of 30 ° to 150 °.

(Fifth Embodiment) FIG. 8 is a structural explanatory view showing a molecular beam source cell 401 of a fifth embodiment. In FIG. 8, the molecular beam source cell 401 of the fifth embodiment includes a crucible 402 filled with a molecular beam material, a heater 403 (corresponding to one heater part of the present invention), and a heater 404 (corresponding to the other heater part of the present invention). 405), a thermocouple 406, and a reflection plate 407. The crucible 402 is PBN as an example.
The shape of the whole crucible is, for example,
The shape is bent at 35 °. One side of the crucible is sealed, and this portion is a material filling portion 410 for filling the molecular beam material 408. The other end of the crucible is opened and forms a molecular beam shape determining part 411 for determining the shape of the molecular beam.

The two systems of heaters 403 and 404 are arranged so as to cover the molecular beam shape determining portion 411 and the material filling portion 410 of the crucible 402, respectively, and cover almost the entire crucible 402 with the two systems of heaters. The two thermocouples 405 and 406 are arranged to measure the temperatures of the molecular beam shape determining part 411 and the material filling part 410, respectively. Therefore, the temperature of the molecular beam shape determining portion 411 and the material filling portion 410 can be independently controlled.

FIG. 9 is a schematic structural explanatory view of an MBE apparatus 501 using a molecular beam cell according to the fifth embodiment. In FIG. 9, the MBE apparatus 501 includes a molecular beam source cell 502, a substrate holder 503 having a substrate rotating / heating mechanism, a shroud 5
04, the crucible inlet opening of the molecular beam source cell 502 faces the center of the substrate holder 503, and the molecular beam
For example, it is set to be incident at an angle of 25 ° with respect to the normal direction of 03. Further, the MBE device 501 is installed so as to be inclined so that the rotation axis of the substrate holder 503 is horizontal.

When the molecular beam source cell of the fifth embodiment is used in such a configuration, 300 cc or more of the molten molecular beam material can be filled. For comparison, FIG. 10 shows a conventional conical crucible. The filling amount is 20 cc, the filling amount of the molecular beam source cell of this embodiment is about 15 times, and the material filling cycle is 5 times or more. Therefore, the product cost can be reduced to 2/3 or less. When the crucible shown in FIG. 10 is used, the evaporation area becomes smaller as the material is consumed and the liquid level is lowered. Therefore,
When the heater temperature is constant, the flux intensity decreases. Therefore, it is necessary to always correct the heater temperature in order to obtain a constant flux intensity. Normally, this flux correction needs to be performed after several growths. When the molecular beam source cell according to the present embodiment is used, the evaporation area does not change even when the material is consumed and the liquid level is lowered. Therefore, even when the heater temperature is constant, the flux intensity is substantially constant. Therefore, it is possible to lengthen the interval at which flux correction is performed, and it is possible to improve the operation rate of the apparatus.

For comparison, FIG. 11 shows a conventional cylindrical crucible. The filling amount is about 50 cc, the filling amount of the molecular beam source cell of the present embodiment is about four times, The period can be extended more than twice. Therefore, the product cost can be reduced to 3/4 or less. Further, when the crucible shown in FIG. 11 is used, the evaporation area does not change even if the material is consumed and the liquid level is lowered. Therefore, if the heater temperature is kept constant, the flux intensity is almost constant, and the flux is frequently reduced. No correction is required. However, when the crucible shown in FIG. 11 is used, there is a disadvantage that the molecular beam shape becomes sharper as the material is consumed and the liquid level decreases, so that the film thickness distribution at the position of the substrate holder 503 is deteriorated. .

In this embodiment, the heaters 403 and 404
Is placed so as to cover almost the entire crucible 402,
If there is a portion in the crucible 402 where a heater is not installed, the temperature of that portion drops, so that the molecular beam material cannot be re-evaporated and adheres and deposits. Therefore, it is desirable to arrange the heater so as to cover almost the entire crucible 402. The molecular beam source according to the present invention includes heaters 403 and 404.
Most of the hot parts, such as
Since the arrangement is not covered by the above, the ports of the apparatus and the vacuum vessel of the molecular beam source are likely to be heated to a high temperature. Since a high temperature of the vacuum vessel affects the degree of vacuum, a water cooling jacket 409 may be provided as in this embodiment so that the temperature of the port portion of the apparatus or the vacuum vessel portion of the molecular beam source does not rise. desirable. In this embodiment, the water cooling jacket 409 is provided outside the vacuum, but the same effect can be obtained when a water cooling mechanism is provided outside the heater inside the vacuum.

In the present embodiment, the angle formed by molecular beam shape determining portion 411 of crucible 402 and material filling portion 410 is set to 135 ° as an example, but the same effect can be obtained in the range of 30 ° to 150 °. .

[0082]

As is clear from the above description, according to the molecular beam source of the present invention, the entire shape of the crucible is bent so that the molecular beam material filled in the bottom from the opening opening of the crucible cannot be seen. Therefore, it is possible to prevent impurities coming from the opening from contaminating the molecular beam material accommodated in the bottom of the crucible. Further, the configuration of the material-filled portion is characterized in that the evaporation surface area of the material is substantially uniform without changing according to the amount of the material, whereby a sufficient amount of the molecular beam material can be secured even when the crucible is inclined. In addition, the number of corrections of the heater temperature can be reduced, and uniform molecular beam intensity can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a main part of an MBE apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of the molecular beam source cell of the first embodiment.

FIG. 3 is a schematic sectional view of a main part of an MBE device according to a second embodiment of the present invention.

FIG. 4 is a schematic sectional view of a molecular beam source cell according to the second embodiment.

FIG. 5 is a configuration explanatory view showing a third embodiment of the molecular beam source cell according to the present invention.

FIG. 6 is a schematic configuration explanatory view showing a third embodiment of the molecular beam epitaxy apparatus according to the present invention.

FIG. 7 is a diagram corresponding to FIG. 6, showing a fourth embodiment of the molecular beam epitaxy apparatus according to the present invention.

FIG. 8 is a diagram corresponding to FIG. 5, showing a fifth embodiment of the molecular beam source cell according to the present invention.

FIG. 9 is a diagram corresponding to FIG. 6, showing a fifth embodiment of the molecular beam epitaxy apparatus according to the present invention.

FIG. 10 is a sectional view showing a crucible of a conventional conical molecular beam source.

FIG. 11 is a cross-sectional view showing a crucible of a conventional cylindrical molecular beam source.

FIG. 12 is a cross-sectional view showing another crucible of the conventional molecular beam source.

FIG. 13 is a schematic sectional view of a main part of a conventional MBE apparatus.

FIG. 14 is a schematic sectional view of the conventional molecular beam source cell.

[Explanation of symbols]

1A, 1B, 1C, 21A, 21B, 21C Molecular beam source cell 44A, 44B, 44C Molecular beam source cell 2,22 Crucible 3,23 First heater 4,24 Second heater 5,25 Main body 5a, 25a Tip 6 , 26 substrate 7,27,646 molecular beam material 8,9,28,29 thermocouple 10,30,641 vacuum chamber 11,31 substrate holder 12,32,643 shroud 13,33,651 MBE device 15,35,65 , 75, 85, 95 Opening surface 45A, 45B, 45C Vessel 101, 401 Molecular beam source cell 102, 402 Crucible 103, 403, 404 Heater 104, 405, 406 Thermocouple 105, 407 Reflector 106, 408 Molecular beam material 107 , 409 Water cooling jacket 108, 410 Material filling part 109, 411 Molecular beam shape determining part 10 the vacuum chamber 111 inlet opening 201,301,501 molecular beam epitaxy apparatus 202,302,502 molecular beam source cell 203,303,503 substrate holder 204,304,504 shroud

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kawa ▼ Saki ▲ Takashi 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Makino Noriyuki 22-22-Nagaikecho, Abeno-ku, Osaka-shi, Osaka No. Sharp Corporation (72) Inventor Yasuo Suga 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Prefecture Sharp Corporation (72) Inventor Zenpei 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Sharp stock Company F term (reference) 4G077 SC12 5F103 AA04 BB02 BB11 BB19 BB23 BB26 RR01 RR08

Claims (14)

[Claims] 1. A molecular beam, comprising: a crucible having an inlet opening, wherein the crucible is bent so that a molecular beam material filled therein cannot be seen from the inlet opening. source. 2. The molecular beam source according to claim 1, wherein an opening surface of the inlet opening faces a horizontal direction or a lower side than the horizontal direction. 3. The crucible is cylindrical, and the direction of the central axis between the inlet opening and the portion to be filled with the molecular beam material and the central axis of the portion to be filled with the molecular beam material are flush with each other. The molecular beam source according to claim 1, wherein the molecular beam source is crossed at an angle of 30 to 150 °. 4. A crucible having an inlet opening, and a heater for heating a molecular beam material mounted in the crucible and filled in the crucible, evaporating and sublimating from the inlet opening to generate a molecular beam. Wherein the crucible is bent between a portion for filling the molecular beam material so that the molecular beam material to be filled is not visible from the entrance opening and the entrance opening, and a portion for filling the molecular beam material. A molecular beam source characterized in that each horizontal cross-sectional area is substantially uniform. 5. The molecular beam source according to claim 4, wherein the heater is disposed at least in a portion of the crucible filled with the molecular beam material and a ceiling portion almost directly above the portion. 6. The molecular beam source according to claim 4, wherein the heater is disposed so as to cover substantially the entire crucible. 7. The molecular beam source according to claim 4, wherein the heater heats the other portion of the crucible to a higher temperature than the portion of the crucible charged with the molecular beam material. 8. The molecular beam source according to claim 4, wherein the heater comprises two independently controllable heater portions. 9. The heater comprises two independently controllable heater portions, one for the portion of the crucible filled with the molecular beam material and the other for the other portion of the crucible. Claim 4 to which each is arranged
8. The molecular beam source according to any one of 7. 10. The heater according to claim 4, wherein the heater comprises at least two heaters: a first heater for evaporating the molecular beam material, and a second heater for controlling the amount of the molecular beam generated from the molecular beam material. The molecular beam according to any one of the above. 11. The molecular beam source according to claim 4, further comprising a vacuum vessel covering an outer periphery of the crucible, and a water-cooling jacket mounted on the vacuum vessel. 12. The molecular beam source according to claim 1, a vacuum chamber supporting the molecular beam source, a shroud provided along an inner wall of the vacuum chamber, and the shroud. A molecular beam epitaxy apparatus comprising: a substrate holder provided inside the crucible of the molecular beam source so as to face an opening of the crucible. 13. A molecular beam source comprising two or more molecular beam source portions, these molecular beam source portions being supported vertically one above the other in a vacuum chamber, and having an entrance opening of each crucible facing a substrate holder. 13. The molecular beam epitaxy device according to claim 12, wherein the molecular beam epitaxy device is formed. 14. The molecular beam epitaxy apparatus according to claim 12, wherein the vacuum chamber is installed obliquely.