JPH0241164B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is a molecular beam epitaxial growth method that allows molecular beam epitaxial growth to be performed continuously on molecular beam epitaxial growth substrates (hereinafter simply referred to as growth substrates) one by one. This relates to growth equipment.

FIG. 1 is a schematic diagram showing a conventional molecular beam epitaxial growth apparatus. In the figure, 1 is a vacuum pump, 2 is a growth chamber that is always kept in an ultra-high vacuum and performs molecular beam epitaxial growth, 3 is a substrate preparation room, 4 is a molecular beam source that emits a molecular beam 5, and 6 is its details. As shown in FIG. 2, there is a three-dimensional substrate holder made of a suitable material; Substrates 8, 9 and 10 are each valves.

Note that for convenience of explanation, a vacuum system, a control system, etc. are not shown in the drawings, but they are of course provided.

Next, a procedure for performing molecular beam epitaxial growth using the molecular beam epitaxial growth apparatus having the above configuration will be explained.

First, the valves 8 and 9 are closed and the valve 10 is opened, and the substrate holder 6 with the growth target substrate 7 mounted thereon is placed into the substrate preparation chamber 3. Next, the valve 10 is closed and the valve 9 is opened, and the vacuum pump 1 is used to evacuate the substrate preparation chamber 3 until the degree of vacuum in the substrate preparation chamber 3 becomes approximately the same as the degree of vacuum in the growth chamber 2. Next, valve 9
Close the valve 8 and open the growth substrate 7.
The substrate holder 6 with the attached substrate holder 6 is placed in the growth chamber 2. Then, when the molecular beam source 4 is driven, the growth substrate 7 is irradiated with the molecular beam 5 . Therefore, the substance constituting the molecular beam 5 is epitaxially grown on the growth substrate 7. When the molecular beam epitaxial growth is completed, the substrate holder 6 is returned to the substrate preparation chamber 3, the valve 8 is closed, the valve 10 is opened, and the substrate holder 6 is taken out. By repeating this operation many times, a large number of films can be grown by molecular beam epitaxial growth.

However, in the conventional molecular beam epitaxial growth apparatus, the number of growth target substrates 7 that can be loaded into the growth chamber 2 at one time is limited to four at most. Therefore, in order to perform molecular beam epitaxial growth on a large number of growth substrates 7 for the purpose of mass production, it is necessary to load the growth substrates 7 into the growth chamber 2 in multiple batches. In this case, each time the growth substrate 7 is loaded into the growth chamber 2, the substrate preparation chamber 3 must be evacuated and the valves 8 and 10 must be opened and closed. It takes a long time to do so. Moreover, impurities in the substrate preparation chamber 3 due to the opening and closing of the valves 8 and 10 enter the growth chamber 2, resulting in a disadvantage that the purity of the epitaxially grown film is reduced.

Therefore, an object of the present invention is to enable molecular beam epitaxial growth to be performed successively on each growth substrate one by one, thereby enabling mass production and maintaining high purity of the epitaxially grown film. The present invention provides a molecular beam epitaxial growth apparatus that can perform molecular beam epitaxial growth.

In order to achieve such an object, the present invention provides a substrate body each supporting a substrate for molecular beam epitaxial growth to be subjected to molecular beam epitaxial growth, and having an electrode wiring section provided with a heater wire for heating the substrate; A cassette that stores a large number of these board bodies,
A substrate preparation chamber that receives this cassette and has a valve for inserting this cassette from the outside, a growth substrate introduction chamber, a substrate growth chamber where molecular beams are irradiated from a molecular beam source, and a growth substrate extraction chamber. a substrate body storage chamber having a valve for mounting an empty cassette and taking out the cassette to the outside, and a valve provided between the substrate preparation chamber and the substrate body storage chamber, respectively; a detection mechanism that is provided at a boundary between the growth substrate introduction chamber and the substrate growth chamber and detects that the substrate body has moved from the growth substrate introduction chamber to the substrate growth chamber;
When the detection mechanism detects that the substrate body has moved from the growth substrate introduction chamber to the substrate growth chamber, the next substrate body is brought to a movement stop state;
It has a stopper and a pair of magnets for canceling the movement stop state when the preheating of the next substrate body is completed, and is movably provided inside the substrate preparation chamber and the growth chamber, and is located at the tip of the cassette. is moved to a predetermined position in the growth substrate introduction chamber, and the substrate stored in the cassette at this predetermined position is moved through the growth substrate introduction chamber to the position of the detection mechanism. a push rod for moving the push rod from the outside, an external pair of magnets provided outside to move the push rod from the outside by magnetically coupling with a pair of magnets, and an external pair of magnets provided inside the growth chamber for contacting the electrode wiring portion of the substrate body. The surface of the substrate for epitaxial growth of the molecular beam, which has entered the substrate growth chamber, is directly directed to the molecular beam source by a substrate heating pretreatment electrode for supplying current and an external magnetic coupling. The substrate rotation mechanism is provided with a substrate rotation mechanism that rotates the substrate so as to rotate the substrate in a manner that the substrate rotates in a direction opposite to each other.

FIG. 3 is a schematic diagram showing an embodiment of the molecular beam epitaxial growth apparatus according to the present invention. In the figure, reference numeral 11 has a substrate 7 for growth mounted on a substrate holder 12 made of a material such as molybdenum, as shown in detail in FIG. 4, and has an electrode wiring part 13 shown in FIG. 14 is a cassette constructed as shown in FIGS. 6a, 6b, and 6c, and 15 is a cassette whose detailed structure is shown in FIG. As shown in FIG. 7, a growth substrate introducing chamber of the growth chamber 2, 16 a substrate growth chamber in this growth chamber 2, 17 a growth substrate outlet chamber in this growth chamber 2, 18 and 19 valves, Reference numeral 20 indicates a substrate body storage chamber for storing an empty cassette 14, and 21 indicates its detailed configuration in the eighth section.
As shown in the figure, a detection mechanism is provided at the boundary between the growth substrate introducing chamber 15 and the substrate growth chamber 16, 22 is a U-shaped growth table as shown in FIGS. This is a substrate body rotation mechanism whose details are shown in FIG.

The substrate preparation chamber 3 and the growth substrate introduction chamber 15, the substrate growth chamber 16, and the growth substrate extraction chamber 7 in the growth chamber 2 are evacuated to the same degree of vacuum as the growth chamber 2. Further, the substrate body storage chamber 20 and the growth substrate body discharge chamber 17 are inclined so that the substrate body 11 that has entered the substrate body 11 slides under its own weight and is stored in the empty cassette 14 of the substrate body storage chamber 20. In the substrate body 11 shown in FIGS. 4 and 5, 11a and 11b are two upper protrusions and two lower protrusions formed on the upper and lower parts of the substrate holder 12, respectively, in order to smoothly transport the substrate body 11. The protrusions 11c protrude higher than the surface of the growth substrate 7 in order to prevent the surface of the growth substrate 7 from colliding with the adjacent substrate holder 12 when the substrate body 11 is packed into the cassette 14. The collision prevention protrusion 11d is provided in the substrate growth chamber 1 in order to epitaxially grow the growth substrate 7 one by one.
The substrate holder 12 passes through the substrate growth chamber 16 so that only one substrate body 11 can enter the substrate growth chamber 6 at any time.
This is an electrode contact surface (hereinafter simply referred to as "confirmation contact surface") for confirming the passage of the substrate provided on the upper surface of the substrate holder 12 to confirm that the substrate has entered the substrate. Note that this substrate body 11 is connected to the opening 14c of the cassette 14 (FIG. 6c).
The cassette 14 is packed in the cassette 14 so that the surface of the growth substrate 7 faces the opening direction of the growth chamber 2, and the cassette 14 is installed in the substrate preparation chamber 3 so that the opening 14c of the cassette 14 faces the growth chamber 2. Furthermore, in the electrode wiring section 13 shown in FIG.
25a and 25b are substrate heating electrodes provided on the protrusion 11a of the substrate body 11, and 26 is an insulator for insulating the heater wire 24 and the substrate heating electrode 25. Also,
In the cassette 14 shown in FIGS. 6a, 6b, and 6c, 14a and 14b are guide grooves for guiding the upper projection 11a and lower projection 11b of the substrate holder 12, respectively, and 14c is a guide groove in which the substrate body 11 moves. 14d is the opening for the push rod (7th
pin grooves 14e and 1 for inserting the
It is a through hole with 4f. Also, in Figure 7,
27 is a push rod with a pin 27a, 28 is a pair of magnets provided at the end of this push rod 27, and 29 is an external magnet pair that is magnetically coupled with this magnet pair 28 in order to rotate and move this push rod 27 from the outside. be. Note that in FIG. 7, only one substrate body 11 is shown for convenience of explanation. Also,
In the detection mechanism 21 shown in FIG.
a stopper 3 for preventing two or more substrate bodies 11 from entering the substrate growth chamber 16 at the same time when entering the substrate growth chamber 16;
1, in order to operate this stopper 30, the substrate body 11 is connected to the growth substrate introduction chamber 15 and the substrate growth chamber 16.
A reference numeral 32 designates a substrate passage confirmation electrode for confirming that the substrate 11 has passed through the boundary surface, and a substrate heating pretreatment electrode 32 for preheating the growth substrate 7 of the substrate body 11 . In addition, in the substrate rotation mechanism 23 shown in FIG. 10, 33 is an L-shaped protrusion provided at the opening side of the growth table 22, and 34 is an L-shaped protrusion 33 that is connected to the growth chamber by using a magnetic coupling (not shown). This is a drive arm that is rotationally driven in the direction of the arrow from the outside. Although the vacuum system and control system are not shown in FIG. 3 as in FIG. 1, it goes without saying that they are provided.

Next, the operation of the molecular beam epitaxial growth apparatus having the above configuration will be explained with reference to FIGS. 4 to 12.

First, the substrate 7 for growth is attached to the substrate holder 12 as shown in FIG. 4 to form the substrate body 11. Then, the upper projection 11a and lower projection 11b of the substrate body 11 are fitted into the guide grooves 14a and 14b of the cassette 14 shown in FIGS. 6a to 6c. In this way, a large number of substrate bodies 11 are placed in the cassette 1.
Attach it to 4. Then, the cassette 14 containing the substrate body 11 is set in the substrate preparation chamber 3 as shown in FIG. On the other hand, an empty cassette 14 is set in the substrate storage chamber 20. Next, the valve 8 is opened, and the tip of the cassette 14 containing the substrate 11 is inserted into the growth substrate introduction chamber 15 at a predetermined position 15a (the first
At the same time, the valve 18 is opened and the tip of the empty cassette 14 is moved to a predetermined position 17a (see FIG. 11) in the growth substrate outlet chamber 17. As shown in FIG. 7, the movement of the cassette 14 is as shown in FIG. 7. When the external magnet pair 29 is moved, the magnetically coupled magnet pair 28 is also moved, so that the push rod 27 is moved. By this movement of the push rod 27, the cassette 14 containing the substrate body 11 is moved to a predetermined position 15a (see FIGS. 7 and 11) in the growth substrate introduction chamber 15. When the external magnet pair 29 is rotated, the magnetically coupled magnet pair 28 is also rotated, so the push rod 27 is also rotated, and the pin 27a and the pin groove 1 of the cassette 14 are rotated.
4e and 14f are combined. Then, when the external magnet pair 29 is moved again, the push rod 27 is inserted into the cassette 14 via the magnetically coupled magnet pair 28, and the substrate body 11 is moved as shown in FIG. into the introduction chamber 15. Meanwhile, move the empty cassette 14 in the same way,
As shown in FIG. 11, the growth substrate deriving chamber 17
set at the predetermined position 17a. Next, as shown in FIG. Stops at. Then, spring-shaped substrate heating pretreatment electrodes 32 are brought into contact with the substrate heating electrodes 25a and 25b on the upper protrusion of the substrate body 11, respectively. For this reason, the substrate body 11
Since a current flows through the internal heater wire 24 (see FIG. 5), the growth substrate 7 mounted on the substrate body 11 is preheated. Next, the stopper 30 is removed and the substrate body 11 is placed in the substrate growth chamber 16.
When the substrate body is pushed inward, the pair of substrate body passage confirmation electrodes 31 comes into contact with the confirmation contact surface 11d of the substrate body 11, and a current flows between the substrate body passage confirmation electrodes 31. When the substrate body passage confirmation electrode 31 separates from the confirmation contact surface 11d, this current is cut off, the stopper 30 is activated, and the substrate body 11 to be pushed in next is prevented from entering the substrate growth chamber 16. . Then, the substrate body 11 entered the substrate growth chamber 16
As shown in FIG. 9 or 12, the substrate 7 is rotated 90 degrees by guide grooves 14a and 14b and mounted on the growth stage 22, so that the surface of the substrate 7 to be grown directly faces the molecular beam source 4. Then, the molecular beam 5 emitted from the molecular beam source 4 is irradiated onto the growth substrate 7, and the substance constituting the molecular beam 5 is epitaxially grown. Then, the substrate body 11 with the epitaxially grown substrate 7 mounted thereon is moved to the growth substrate deriving chamber 17, but as shown in FIG. The drive arm 34 is driven from the outside of the L-shaped protrusion 3.
Rotate 3 in the direction of the arrow. Therefore, as shown in FIG. 12, this substrate body 11 is rotated 90 degrees again in the direction of the arrow by the guide groove 35 of the substrate growth chamber 16 and slides down into the growth substrate body outlet chamber 17. In addition, this L-shaped protrusion 33 rotates in the opposite direction and connects to the growth table 22.
It is returned to the same plane. Then, the substrate body 11 is stored in an empty cassette 14. On the other hand, the substrate body 1
The guide groove 1 of the growth substrate introduction chamber 15 is designed to smoothly and accurately perform the two rotations of the growth substrate introduction chamber 15.
4a, 14b and the guide grooves 14a, 14b of the growth substrate outlet chamber 17, the guide grooves 35 of the substrate growth chamber 16 intersect with each other in a curved line (see FIG. 12). By repeating the above steps,
The epitaxial growth of the substrate bodies 11 set in the cassette 14 onto the growth substrate 7 is successively completed one by one, and all of the completed substrate bodies 11 are stored in the empty cassette 14. Then, make sure that the pins of the push rod (not shown) do not enter the pin grooves 14e and 14f of this cassette 14,
By pulling back this push rod (not shown),
The cassette 14 containing the completed substrate 11 is loaded and returned to the substrate storage chamber 20. Then, by closing the valve 18 and opening the valve 19, the cassette 14 can be taken out.

Although the capacity of the cassette 14 is limited by the size of the substrate preparation chamber 3, it is of course possible to lengthen the substrate preparation chamber 3 and increase the capacity of the cassette 14. In addition, the substrate holder 1
Of course, the number and shape of the upper protrusion 11a and lower protrusion 11b, the guide grooves 14a and 14b, and the collision prevention protrusion 11c are not limited to these, and can be arbitrarily determined. Also, push rod 2
The operating mechanism of 7 used a magnetic coupling, but
It goes without saying that the format is not limited to this, and any format can be used. In addition, the growth substrate derivation chamber 17
It goes without saying that the inclination of the substrate storage chamber 20 may be arbitrarily determined within the range of 1 degree to 90 degrees with respect to the horizontal. Further, although the rotation of the substrate 11 entering the substrate growth chamber 16 from the growth substrate introduction chamber 15 was set to 90 degrees, it is of course possible to rotate the substrate 11 at any angle as long as it directly faces the molecular beam source 4.

As described in detail above, according to the molecular beam epitaxial growth apparatus according to the present invention, a cassette containing a large number of substrate bodies is moved from the substrate preparation chamber to the growth substrate introduction chamber, and the growth substrate body is The substrates are moved one by one from the introduction chamber to the substrate growth chamber, molecular beam epitaxial growth is performed on the growth substrate supported by the substrate, and then the substrates are transferred one by one into another cassette. By storing the growth substrate, molecular beam epitaxial growth can be performed continuously one by one, making mass production possible.Moreover, molecular beam epitaxial growth films formed on the growth substrate can be can be kept at high purity.

In addition, the push rod that moves the cassette and substrate body, and the substrate rotation mechanism that rotates the substrate body so that the surface of the substrate to be grown directly faces the molecular beam source, are operated by a pair of magnets that are magnetically coupled with an external device. Because it is driven, there is no risk of dust generation in the substrate preparation chamber, growth chamber, and substrate storage chamber, and the high purity of the molecular beam epitaxial growth film formed on the growth substrate can be maintained in the same way as mentioned above. .

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a conventional molecular beam epitaxial growth apparatus, FIG. 2 is a perspective view showing a substrate holder equipped with the substrate for molecular beam epitaxial growth shown in FIG. 1, and FIG. 3 is a diagram showing the present invention. 4 and 5 are a perspective view showing the substrate body of FIG. 3 and a sectional view showing its electrode wiring portion, and FIG.
Figures a, 6b and 6c are a left side view, a sectional view and a right side view of the cassette shown in figure 3;
The figure is a diagram for explaining the relationship between the substrate preparation chamber and the growth substrate introduction chamber when loading the cassette in Figure 3, Figure 8 is a perspective view showing the detection mechanism in Figure 3, and Figure 9 is a A perspective view showing the state of the substrate body in the growth substrate body introduction chamber and the substrate growth chamber shown in FIG.
The figure is a perspective view showing the substrate body rotation mechanism in Figure 3.
1 is a plan view for explaining the operation of FIG. 3, and FIG. 12 is a sectional view showing the growth substrate introduction chamber, the substrate growth chamber, and the growth substrate discharge chamber of FIG. 3. 1... Vacuum pump, 2... Growth chamber, 3... Substrate preparation room, 4... Molecular beam source, 5... Molecular beam, 6...
Substrate holder, 7... Substrate for molecular beam epitaxial growth, 8, 9 and 10... Bulb, 11...
Substrate body, 12... Substrate holder, 13... Electrode wiring section, 14... Cassette, 15... Growth substrate introduction chamber, 16... Substrate growth chamber, 17... Growth substrate derivation chamber, 18 and 19... Valve, 20...
Substrate body storage chamber, 21...Detection mechanism, 22...Growth stage, 23...Substrate body rotation mechanism, 24...Heater wire, 25a and 25b...Substrate heating electrode, 2
6... Insulator, 27... Push rod, 27a...
Pin, 28... Magnet pair, 29... External magnet pair, 3
0...stopper, 31...electrode for confirming passage of the substrate, 32...electrode for substrate heating pretreatment, 33...L
Character Tsute, 34... Drive arm. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A substrate body each supporting a substrate for molecular beam epitaxial growth to be subjected to molecular beam epitaxial growth, and having an electrode wiring section provided with a heater wire for heating the substrate, and a plurality of these substrate bodies. a substrate preparation chamber having a cassette for storing the substrates, a valve for receiving the cassette and inserting the cassette from the outside, a growth substrate introduction chamber, a substrate growth chamber to which molecular beams are irradiated from a molecular beam source, and a growth chamber. a growth chamber having a substrate body ejection chamber; a substrate body storage chamber having an empty cassette and a valve for taking out the cassette to the outside; and a substrate body storage chamber between the substrate preparation chamber and the substrate body storage chamber. a detection mechanism provided at the boundary between the growth substrate introduction chamber and the substrate growth chamber to detect movement of the substrate from the growth substrate introduction chamber to the substrate growth chamber; When the detection mechanism detects that the substrate body has moved from the growth substrate introduction chamber to the substrate growth chamber, the movement of the next substrate body is stopped, and when preheating of the next substrate body is completed. has a stopper for canceling the movement stop state, and a pair of magnets, and is movably provided inside the substrate preparation chamber and the growth chamber, and is configured to move the tip of the cassette to a predetermined position in the growth substrate introduction chamber. a push rod for moving the substrate housed in the cassette at the predetermined position through the growth substrate introduction chamber to the position of the detection mechanism; , an external magnet pair for moving the push rod from the outside by magnetically coupling with the magnet pair; and a pre-heating magnet for supplying current by contacting the electrode wiring portion of the substrate body, which is provided in the growth chamber. A processing electrode, and a substrate rotation mechanism that is driven by an external magnetic coupling and rotates the surface of the substrate for molecular beam epitaxial growth that has entered the substrate growth chamber so as to directly face the molecular beam source. A molecular beam epitaxial growth apparatus characterized by: