JP2830467B2 - Single crystal manufacturing equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for growing a single crystal of a compound containing a volatile component by a Czochralski vapor pressure control method.

[Prior Art] FIG. 3 shows an example of a conventional technique for producing a single crystal by a Czochralski method with vapor pressure control. In the apparatus shown in FIG. 3, a susceptor 6 is rotatably provided at a lower portion, and a crucible 9 is placed on the susceptor 6. An annular groove 6a is formed around the upper part of the susceptor 6, and a sealing agent 8 is stored in this groove. Above the center of the crucible 9,
A pulling shaft 4 for pulling a single crystal is rotatably provided, and a seed crystal 3 is attached to a lower end thereof. A conical airtight container 5 is provided so that the pulling shaft 4 is passed through the liquid reservoir 5 a and covers the crucible 9. Airtight container 5
The leg 5b is fitted in the annular groove 6a and is immersed in the sealant 8. Further, the gap between the liquid reservoir 5a of the airtight container 5 and the lifting shaft 4 is also sealed by the sealant 8. In this way, the crucible 9 is sealed by the airtight container 5 and the susceptor 6, and a sealed growth chamber 10 for growing a single crystal is formed above the crucible. On the other hand, from the airtight container 5 to the susceptor 6, a heater 7
a, 7b and 7c are provided.

In the apparatus configured as described above, in order to pull up a single crystal, a melt 1 of a compound containing a volatile component is prepared in a crucible 9, and a seed crystal 3 at a lower end of a pulling shaft 4 is added to the melt. The pull-up shaft 4 is rotated and raised while the temperature is controlled by the heater, and the seed crystal 3 is pulled up. At this time, in the growth chamber 10 sealed by the airtight container 5 and the susceptor 6, an atmosphere of a volatile component is formed at a predetermined pressure.

[Problem to be Solved by the Invention] In the above apparatus, the surface of the airtight container 5 is coated with PBN or the like so that volatile components and the like in the growth chamber sealed by the airtight container do not leak outside. However, the part immersed in the sealant with such a coating, for example, the coating of the leg 5b of the hermetic container 5,
During the growth of the single crystal many times, it may peel off. This is because when cooling the inside of the airtight container 5,
It is considered that the sealing agent 8 solidifies and contracts. If the coating is peeled off in this way, the vapor of the volatile component in the reaction chamber leaks, and it becomes impossible to stably grow the single crystal.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a single-crystal backing imaging apparatus which does not cause leakage of volatile component vapor and the like even when used continuously for a long period of time.

[Means for Solving the Problems] A single crystal manufacturing apparatus according to the present invention is a single crystal manufacturing apparatus for manufacturing a single crystal of a compound containing a volatile component by a Czochralski method. A crucible, a susceptor for placing the crucible, an annular groove formed around the susceptor for storing a sealant, and a sealant covering the crucible and having legs stored in the annular groove An airtight container that seals the crucible with the susceptor by forming a coating surface on at least one of the inner surface and the outer surface for preventing the passage of volatile component vapors. It is characterized in that a protective member for preventing erosion of the coating surface is provided on the coating surface of the leg.

The material of the protection member according to the present invention may be, for example, carbon.

[Operation and Effect of the Invention] In the single crystal manufacturing apparatus according to the present invention, the crucible is covered,
A protective member is provided on the coating surface of the leg among the coating surfaces of the airtight container that seals the crucible together with the susceptor. With this protective member, the coating surface of the leg is protected from erosion due to solidification shrinkage of the sealant. In the conventional apparatus, as described above, the coating surface used for the sealant of the legs of the hermetic container peels off, resulting in a situation in which the hermeticity is reduced. However, in the device according to the present invention, since the coating surface is protected by the protective member as described above, a situation in which airtightness is reduced due to peeling of the coating surface is avoided. Therefore, the apparatus according to the present invention does not peel off the coating surface even when the crystal is continuously grown for a long period of time, and does not leak the volatile component vapor or the like. As described above, the apparatus of the present invention is excellent in durability and can pull up a high-quality single crystal for a long period of time.

Embodiment FIG. 1 is a sectional view showing a single crystal manufacturing apparatus according to the present invention. This device has a structure in which a crucible 9 for accommodating a melt 1 of a compound is placed on a susceptor 6 and sealed by an airtight container 5 as in the above-described conventional device. A liquid reservoir 5a is formed in the hermetic container 5 as in the prior art, and a pull-up shaft 4 to which a seed crystal 3 is attached is passed through at the lower end, and its leg 5b is formed in an annular groove 6a And covers the crucible 9. In addition, the gap between the annular groove 6 and the liquid reservoir 5a and the lifting shaft 4 is sealed with a sealant 8 as in the conventional case. Above the crucible 9 sealed with the susceptor 6 and the airtight container 5 in this manner,
A sealed growth chamber 10 is formed. Further, a heater 7a and a heater 7a are provided around the airtight container 5 to the susceptor 6.
7b and 7c are provided.

In the device configured as described above, a protection member 11 is attached to the leg 5b of the airtight container 5 as shown in the figure. FIG. 2 is an enlarged sectional view showing a state where the protection member 11 is attached. As shown in FIG. 2, an L-shaped protection member 11 is screwed on the inner wall of the leg 5b of the airtight container 5.
Installed by 12. The protection member 11 is in close contact with the inner wall of the leg 5b, and covers the tip of the leg 5b. Airtight container 5
A coating layer 5c for maintaining airtightness is formed on the inner surface of the substrate, but by providing the protective member 11 in this manner, the coating layer 5c does not come into contact with the sealant 8 in the annular groove 6a. . In consideration of the possibility that droplets are generated from the surface of the sealant 8 and adhere to the airtight container 5, the sealant 8
Protect the airtight container 5 from the surface of the
Erosion by droplets can also be prevented.

A GaAs single crystal was grown using the above-described apparatus. In the device, the crucible is made of PBN with an inner diameter of 4 inches,
The airtight container is made of carbon and has an inner diameter of 6.2 inches and a wall thickness of 0.4 inches. The inner wall is coated with PBN. Also,
The protection member has a cylindrical shape and is made of carbon having an inner diameter of 6 inches and a thickness of 0.2 inches. 1 kg of GaAs polycrystal as raw material
After charging the crucible, the growth chamber was set to an atmosphere of 5 atm As, and the raw material charged in the crucible was heated and melted by a heater. Next, after lowering the pull-up shaft and allowing the seed crystal to sufficiently adapt to the melt, the temperature is adjusted to the crystal growth temperature by a heater,
The crystal was pulled at a rotation speed of the pulling shaft of 5 rpm, a rotation speed of the susceptor of 10 rpm, and a pulling speed of the pulling shaft of 6 mm / hr. When the crystal was repeatedly grown ten times, the dimensions of the obtained crystals were all around 60 mmφ × 120 mm. Airtight container P
Peeling of the BN coat was scarcely observed, and the single crystallization ratio of the obtained crystals was as high as about 80%. Thus, the apparatus according to the present invention has high performance as a single crystal manufacturing apparatus.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a single crystal manufacturing apparatus according to the present invention. FIG. 2 is an enlarged sectional view showing an attached state of the protection member shown in FIG. FIG. 3 is a sectional view showing an example of a conventional single crystal manufacturing apparatus. In the figure, 1 is a melt, 2 is a single crystal, 3 is a seed crystal, 4 is a pulling shaft, 5 is an airtight container, 6 is a susceptor, 8 is a sealant, 9
A crucible, 10 is a growth chamber, 11 is a protective member, and 12 is a screw.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-286992 (JP, A) JP-A-3-252385 (JP, A) JP-A-1-317186 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) C30B 27/02 C30B 15/00

Claims (1)

(57) [Claims] 1. A single crystal manufacturing apparatus for manufacturing a single crystal of a compound containing a volatile component by a Czochralski method, comprising: a crucible for containing a melt of the compound; and a susceptor for mounting the crucible. Around the susceptor, an annular groove formed for storing a sealant, covering the crucible, a leg portion is immersed in the sealant stored in the annular groove, and the volatile An airtight container that seals the crucible with the susceptor by forming a coating surface for preventing the passage of component vapors, and prevents the coating surface from eroding on the coating surface of the airtight container legs. A single crystal manufacturing apparatus, comprising: a protection member provided for the same.