JP2664085B2 - Compound semiconductor single crystal manufacturing equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for producing a compound semiconductor single crystal by a vertical temperature gradient method.

[Prior art] Vertical Gradient Freeze Meth
od) according to conventional manufacturing equipment, for example,
earch Society Symposia Proceedings, volume90, p.1
11-p.118). In these conventional manufacturing apparatuses, after putting raw materials in a quartz tube which is a growth container,
A growth ampoule is prepared by vacuum encapsulation, the growth ampule is set in a furnace to start growth, and after the growth is completed, the ampoule is cracked to take out a crystal grown therein.

FIG. 2 is a schematic sectional view showing an example of such a conventional manufacturing apparatus. Put the raw materials in the container 21 and then
Is melted by a cap 24 and heated by a heater 26 to form a melt 22, and the melt 22 is gradually cooled and solidified to grow a grown crystal 23. Note that the cap 24 is attached to the tip of the shaft 25.

[Problems to be Solved by the Invention] However, in such an apparatus, when a compound semiconductor containing a component having a high vapor pressure such as CdTe is grown, the component having a high vapor pressure evaporates in the container 21, There is a fear that the internal pressure in the container increases and the container is broken. Further, when a single crystal is manufactured by such a conventional apparatus, there is a problem that after the growth is completed, the container must be broken and taken out in order to take out the single crystal.

Further, as described above, in the conventional manufacturing apparatus, there is also a problem that after the raw material is put in the container, the opening of the container must be welded and sealed with a cap. The conventional manufacturing apparatus requires such a welding process or a process in which the growth crystal must be taken out by destroying the container, which is not preferable from the viewpoint of the production process, and the cost is high.

An object of the present invention is to provide a compound semiconductor single crystal manufacturing apparatus capable of efficiently growing a compound semiconductor single crystal by solving the conventional problems and simplifying a production process.

[Means for Solving the Problems] The production apparatus of the present invention comprises: placing a raw material in a growth vessel, sealing the growth vessel with a cap, and heating the raw material inside the growth vessel to form a melt; An apparatus for manufacturing a compound semiconductor single crystal by a vertical temperature gradient method in which a melt is gradually cooled from below to solidify and grow a compound semiconductor single crystal, and an annular ring along the opening of the growth vessel is provided at the top of the growth vessel. A liquid reservoir is provided, and a peripheral wall portion extending downward in a cylindrical shape is provided at a peripheral edge portion of the cap, and the tip of the peripheral wall portion is immersed in the liquid in the liquid reservoir, so that the growth container is provided. Is characterized by being sealed.

[Operation] In the manufacturing apparatus of the present invention, the growth vessel is hermetically sealed by immersing the tip of the peripheral wall of the cap in the liquid reservoir at the top of the growth vessel. For this reason, it is not necessary to weld the cap to the opening of the growth container as in the related art, and such a step is not required.

Further, after the growth is completed, the crystal grown in the growth vessel can be taken out by pulling up the tip of the peripheral wall of the cap from the liquid reservoir of the growth vessel. Disappears.

Further, when the internal pressure increases due to evaporation of the volatile element in the growth vessel, the pressure between the inside and the outside can be balanced by increasing the pressure outside the growth vessel. For this reason, unlike the conventional case, the internal pressure does not increase during the growth and the container is not damaged.

Embodiment FIG. 1 is a schematic sectional view showing an embodiment of the present invention. A raw material container 2 is placed in the growth container 1, and the raw material is placed in the raw material container 2.

Above the growth vessel 1, a liquid reservoir 9 is provided along the outer peripheral surface of the opening, and in the liquid reservoir 9, a sealant 6 is put. In the liquid sealing agent 6 in the liquid reservoir 9, the tip of the peripheral wall portion 10 extending downward from the peripheral end of the cap 5 in a cylindrical shape is immersed. The cap 5 is supported by a shaft 12.

The raw material placed in the growth vessel 1 is heated by the heater 7 to become the melt 3. Below the raw material container 2,
A seed mounting portion 11 is provided.
Is equipped with a seed crystal. The melt 3 is solidified by being gradually cooled from below, and the grown crystal 4 grows.

The entire device is housed in a pressure vessel 8.

At the time of crystal growth, when a component element having a high vapor pressure evaporates from the melt 3 and the pressure in the growth vessel 1 increases, a pressure corresponding to the pressure in the pressure vessel 8 is applied to increase the pressure inside the growth vessel 1. Balance pressure with external pressure.

Further, when removing the grown crystal after the completion of the growth, the axis 12
And the tip of the peripheral wall 10 of the cap 5 may be pulled up from the liquid reservoir 9.

Hereinafter, an experimental example in which a single crystal of CdZnTe is grown using the apparatus shown in FIG. 1 will be described.

As a raw material, 500 g of CtTe and 6.75 g of ZnTe are put in the raw material container 2. The raw material container 2 is formed by coating glassy carbon on a carbon base material.

The diameter of the wide mouth portion of the raw material container 2 is 40 mm, and the diameter of the narrow mouth portion is 30 mm. The length from the wide mouth to the narrow mouth is 80 mm, and it is connected to a 40 mm long, 5 mm square seed mounting part 11.

The growth vessel 1 is provided so as to hold the raw material vessel 2, and is formed by coating the inner surface of a quartz ampule with glassy carbon. The cap 5 is also a quartz base material coated with glassy carbon.

The materials of the growth container 1, the material container 2 and the cap 5 are not necessarily limited to the above-mentioned combination, but those having appropriate wettability, airtightness, and in which the reaction with the material is not remarkable, for example,
BN, P-BN, carbon, pyrolytic carbon and the like may be used.

The liquid reservoir 9 contains 250 g of B ₂ O ₃ as the sealant 6.

The growth procedure is as follows. First, the cap 5 is positioned upward, and the growth vessel 1 is evacuated while the opening is opened, and then the sealing agent 6 in the liquid reservoir 9 is melted by the heater 7. When the temperature reached 800 ° C., the tip of the peripheral wall portion 10 of the cap 5 was lowered into the melted B ₂ O ₃ to seal the inside of the growth vessel 1.

Next, the temperature of the raw material portion was increased, and the inside of the pressure vessel 8 was filled with an inert gas and pressurized so as to be balanced with the vapor pressure of Cd. The temperature at which the melt 3 is completely melted is about 1200 ° C
At this time, the inside of the pressure vessel 8 was set to 5 atm. In this state, after holding for about 2 hours, the temperature gradient near the growth interface is set to 5 to 10 ° C./cm, and the growth interface is set to 0.5 to 2 mm / hr.
Moved.

After all the melt 3 is solidified, the grown crystal is heated at 3 to 5 ° C /
When the temperature reached 650 ° C., the cap 5 was raised to open the sealed state of the growth vessel 1, and then cooled to around room temperature to take out a grown crystal.

The grown crystal obtained as described above was almost the same as the grown crystal obtained by the conventional apparatus.

In this embodiment, the growth of a CdZnTe compound semiconductor single crystal has been described as an example, but the manufacturing apparatus of the present invention can be applied to the manufacture of other compound semiconductor single crystals.

[Effects of the Invention] As described above, in the manufacturing apparatus of the present invention, the growth container is provided by providing the liquid reservoir in the upper part of the growth container and dipping the tip of the peripheral wall of the cap into the liquid reservoir. Sealed. Therefore, unlike the conventional manufacturing apparatus, a step of welding the cap to the container is not required, and the step can be simplified.

Further, in the manufacturing apparatus of the present invention, since the inside and the outside of the growth container are in contact with each other via the liquid in the liquid reservoir, when the pressure inside the growth container increases, the outside of the growth container is By increasing the pressure, the balance between the inside and the outside of the growth vessel can be balanced, and there is no possibility that the growth vessel is destroyed due to an increase in the internal pressure during the manufacturing process unlike the conventional manufacturing apparatus.

Further, in the manufacturing apparatus of the present invention, the growth container can be easily opened by pulling up the tip of the peripheral wall portion of the cap from the liquid in the liquid storage section after the growth is completed, as in the conventional manufacturing apparatus. Therefore, it is not necessary to destroy the growth container every time the growth is performed.

As described above, by using the manufacturing apparatus of the present invention, the same growth vessel can be used repeatedly, and the process can be greatly simplified, so that the productivity is excellent.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of the present invention. FIG. 2 is a schematic sectional view showing an example of a conventional device. In the figure, 1 is a growth vessel, 2 is a raw material vessel, 3 is a melt, 4 is a growth crystal, 5 is a cap, 6 is a sealant, 7 is a heater, 8 is a pressure vessel, 9 is a liquid reservoir, Reference numeral 10 denotes a peripheral wall portion, 11 denotes a seed mounting portion, and 12 denotes a shaft.

Claims (1)

(57) [Claims] After the raw material is put in the growth vessel and the growth vessel is sealed with a cap, the raw material in the growth vessel is heated to obtain a melt, and the melt is gradually cooled from below to be solidified. In an apparatus for manufacturing a compound semiconductor single crystal by a vertical temperature gradient method for growing a compound semiconductor single crystal, an annular liquid reservoir along an opening of the growth vessel is provided at an upper portion of the growth vessel, and a periphery of the cap is provided. A compound is characterized in that a peripheral wall portion extending downward in a cylindrical shape is provided at an end portion, and the tip of the peripheral wall portion is immersed in the liquid in the liquid storage portion to seal the growth container. Semiconductor single crystal manufacturing equipment.