JP2876765B2 - Method and apparatus for growing single crystal - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for growing a single crystal of a III-V compound semiconductor such as GaAs and InP.

[Prior Art] When a single crystal such as a compound semiconductor is manufactured by a pulling method, a method in which a crucible is charged only once with a raw material single crystal or a raw material element or an impurity at first and does not replenish the raw material on the way is dominant. It is a target. In such a method, the size of the single crystal to be pulled is limited by the amount of the raw material single crystal and the like initially charged into the crucible.

Therefore, a method of replenishing a single crystal into a raw material melt during pulling has been developed for the purpose of pulling a longer single crystal without increasing the size of the crucible. As such a method, the method disclosed in JP-A-61-158897 can be mentioned.

In this method, a single crystal is manufactured using, for example, the apparatus shown in FIG. This manufacturing method will be described below.
Referring to FIG. 2, a crucible 24 is provided in a susceptor 23 supported by a rotatable lower shaft 22. The raw material melt 25 is accommodated in the crucible 24, and the temperature is controlled by the heater 21. The raw material melt 25 is entirely covered with a liquid capsule layer 26. An upper shaft 33 is hung above the center of the crucible 24, and a seed crystal 27 is mounted at the lower end. The upper shaft 33 is rotatable up and down. To produce a single crystal, the upper shaft 33 is lowered, the seed crystal 27 is immersed in the raw material melt 25, and then the single crystal is pulled up by raising the upper shaft 33.

In addition to the above steps, in this method, the replenishment crystal 29 hung on the support rod 30 is stored in the liquid capsule holding cylinder 32,
This is immersed in the raw material melt 25 in the crucible 24. Then, the support rod 30 is lowered, and the supply crystal 29 is gradually introduced into the raw material melt 25.
Immerse. While pulling up the single crystal, the replenishing crystal 29 gradually melts from its tip in the crucible 24 and replenishes the raw material melt 25.

[Problems to be Solved by the Invention] When the above-described method for producing a single crystal is applied to the vapor pressure control pulling method, the above-described material supply mechanism is provided in an airtight container accommodating necessary equipment such as a crucible. Must be provided. In this case, the material supply mechanism has a very complicated structure in terms of maintaining airtightness and the like. Further, since the replenishing material is provided in the hermetic container, the supply amount of the replenishing material is also limited by the size of the hermetic container. Furthermore, in the above-mentioned method, since a crystal synthesized in advance is used as a supplementary material, the cost of the supplementary material is high. Further, the raw material melt may be contaminated with impurities brought in from the replenishing raw material, which may hinder the growth of 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 growth method and a single crystal growth method capable of producing a desired long single crystal with a device having a simpler structure and without the influence of impurities or the like. It is to provide a device.

[Means for Solving the Problems] A method for growing a single crystal according to the present invention is a method for growing a single crystal of a group III-V compound semiconductor by a pulling method. A second crucible having a communicating hole for allowing a melt to flow into the first crucible accommodated therein;
Providing a crucible, pulling a single crystal from the melt flowing into the second crucible through the communicating hole, and supplying a group III element and a group V element to the third crucible when pulling the single crystal To prepare a melt of a III-V compound semiconductor,
Supplying the prepared melt from the third crucible to the first crucible, wherein the surface of the melt prepared in the third crucible is sealed by a sealing agent contained in the third crucible. It is characterized by covering.

Further, the apparatus for growing a single crystal according to the present invention comprises a III-V
An apparatus for growing a single crystal of a group III compound semiconductor by a pulling method, comprising: a first crucible for accommodating a melt of a III-V compound semiconductor; and a first crucible provided in the first crucible;
A second crucible having a communication hole for allowing a melt contained in the crucible to flow therein, and a crystal for pulling a single crystal of a III-V compound semiconductor from the melt flowing into the second crucible A pulling shaft, a mixture of a group III element and a group V element
A third crucible for preparing a melt of a II-V compound semiconductor, a plurality of containers each containing a group III element and a group V element, and a group III element and a group V element from the plurality of containers, respectively. A plurality of raw material supply pipes for supplying to the third crucible; supply means for supplying the melt prepared in the third crucible to the first crucible; a first crucible, a second crucible, and a second crucible. And a high-pressure container accommodating the third crucible, wherein the opening of the third crucible is open to the atmosphere in the high-pressure container.

[Action] According to the single crystal growth method according to the present invention, the second crucible having the communication hole is provided in the first crucible containing the melt, and the melt flowing into the second crucible from the communication hole is provided. The single crystal is pulled from the liquid. When pulling a single crystal, a plurality of raw materials of the melt are supplied to a third crucible, a melt is prepared from these raw materials in the third crucible, and the melt is supplied to the first crucible. I do. Thus, in the present invention,
Since the single crystal is pulled up while supplying the raw material from the outside and preparing the melt, the long single crystal can be pulled up without being limited to the size of the crucible accommodating the melt. What is replenished at the time of pulling up is not the crystal as in the conventional case but the raw material of the melt. Therefore, there is no need to worry about contamination by impurities from the replenishment crystal as in the related art.

The apparatus for growing a single crystal according to the present invention includes a crucible for preparing a melt by mixing the raw materials, and the melt is supplied from the crucible to a crucible for pulling a single crystal by a supply unit. I have. Therefore, according to this device,
In accordance with the above-described method for growing a single crystal, the single crystal can be pulled while supplying the melt.

Embodiment FIG. 1 shows an example of a single crystal growing apparatus according to the present invention. Referring to FIG. 1, this apparatus pulls a single crystal in a high-pressure vessel 2 in which the atmosphere has been replaced by an inert gas 1. In the high-pressure vessel 2, a crucible 3 for crystal growth and a crucible 4 for synthesizing a melt are provided. The lower part of the crucible 3 for crystal growth and the lower part of the crucible 4 for melt synthesis are connected by a communication pipe 5. Further, heaters 13 and 14 are arranged around these crucibles, respectively. The melt 6 is accommodated in the crucible 3 for crystal growth, and an inner crucible 16 is provided. A communication hole 16a is provided at the bottom of the inner crucible 16, so that the melt 6 flows into the inside. On the other hand, above the center of the crystal growth crucible 3, a crystal pulling shaft 9 that can be rotated and raised and lowered.
The seed crystal 10 is attached to the lower end of the crystal pulling shaft 9. In addition, a cylindrical inner crucible rotating shaft 15 is rotatably provided around the crystal pulling shaft 9 so as to surround the shaft. The inner crucible rotation shaft 15 is connected to the inner crucible 16 by an inner crucible suspending jig 18, and the inner crucible 16 rotates within the crystal growth crucible 3 according to the rotation of the inner crucible rotation shaft 15. Both the crystal pulling shaft 9 and the inner crucible rotating shaft 15 pass through above the high-pressure vessel 2, and the penetrated portion is sealed with a sealant (not shown).
On the other hand, an ampoule 17 is provided in the high-pressure vessel 2 above the crucible 4 for melt synthesis. A raw material supply pipe 17a is formed in the ampoule 17, and the raw material supply pipe 17a extends into the crucible 4 for melt synthesis. A heater 23 is provided around the ampoule 17. Further, an ampoule 19 is provided outside the high-pressure vessel 2. A raw material supply pipe 19a is formed in the ampoule 19, and the raw material supply pipe 19a extends into the crucible 4 for melt synthesis through the high-pressure vessel 2. In addition,
The fortune in which the high-pressure vessel 2 is penetrated by the raw material supply pipe 19a is sealed.

As shown in FIG. 1, the raw material (Group V element such as As) contained in the ampoule 17 is supplied to the crucible 4 for synthesizing a melt through a raw material supply pipe 17a. The raw material (Group III element such as Ga) contained in the ampoule 19 is supplied to the melt synthesizing crucible 4 via the raw material supply pipe 19a. In the crucible 4 for melt synthesis,
The respective raw materials are mixed to prepare a melt of a III-V compound semiconductor. The surface of the melt prepared in the melt synthesizing crucible 4 is filled with the sealing agent 7 contained in the melt synthesizing crucible 4.
Covered by The crucible 3 for growing crystals, the inner crucible 16 and the crucible 4 for synthesizing a melt are accommodated in a high-pressure vessel 2. As shown in the figure, the opening of the crucible 4 for melt synthesis is open to the atmosphere in the high-pressure vessel 2.

A single crystal of GaAs was grown using the apparatus configured as described above. First, a crystal growth crucible 3 made of PBN having a diameter of 6 inches is filled with 5 kg of GaAs single crystal and a sealant 7 (B ₂ O ₃ 700
g) is accommodated in the crucible 4 for synthesizing the melt, and the sealant 7 (B ₂ O
₃ 500 g). Also, provided in the high-pressure vessel 2,
In a carbon ampoule 17 whose inner surface is coated with PBN, 5.4 kg of the raw material As is stored and provided outside the high-pressure vessel 2. Similarly, a carbon ampoule 19 whose inner surface is coated with PBN has 5 kg of raw material Ga was stored. Next, after filling the high-pressure vessel 2 with N ₂ gas at a predetermined pressure, the heaters 13 and 14 are filled.
The GaAs single crystal and B ₂ O ₃ charged in advance were melted by heating. The melt after melting flowed from the crucible 3 for crystal growth into the crucible 4 for synthesizing the melt through the communication pipe 5, and the tips of the raw material supply pipes 17a and 19a were submerged in the melt.
Next, the temperature of the ampoule 17 was set to 617 ° C. by the heater 23,
Heater (not shown) provided around raw material supply pipe 17a
, The temperature of the entire As supply system was set to 617 ° C or higher. In the above state, the positions of the crystal pulling shaft 9 and the inner crucible rotating shaft 15 were adjusted, and the inner crucible 16 was immersed in the melt. The crystal pulling shaft 9 is lowered while rotating the crystal pulling shaft 9 at 3 rpm and the inner crucible rotating shaft 15 at 10 rpm in opposite directions,
Seed crystal 10 was immersed in the melt. Then, after controlling the melt to a growth temperature by each heater, the crystal pulling shaft 9 was raised to pull the single crystal. When pulling the single crystal, Ga was continuously supplied from the ampoule 19 so that the position of the melt surface in both crucibles did not change, and As was supplied from the ampoule 17 as a gas of about 1 atm. In this way, the synthesized melt was always kept at a stoichiometric composition.

According to the above process, 3 inches in diameter and 21 inches in length
As a result of growing a GaAs single crystal, the obtained crystal was semi-insulating over the entire region and had uniform characteristics.

In the apparatus used in the above embodiment, the ampoule for supplying As is provided inside the high-pressure vessel. However, the ampule may be provided outside the high-pressure vessel.

[Effects of the Invention] As described above, according to the present invention, a single crystal can be pulled while supplying a raw material, so that a long single crystal can be used without increasing the size of a crucible for accommodating a raw material melt. Can be raised. In addition, even when single crystals need to be grown by a vapor pressure control method in a high-pressure closed vessel to contain highly dissociated components, the melt is prepared by supplying the raw material from the ampule for the raw material to the crucible for synthesizing the melt. This makes it possible to easily charge the melt continuously. Moreover, as shown in the embodiment, the supply mechanism of the raw material and the melt can be simple. Furthermore, since replenishment is performed in the form of constituent materials, there is no concern about contamination by impurities derived from replenishment crystals as in the conventional case. Further, the cost for crystal formation can be reduced as compared with the case where the raw material is continuously charged in the form of crystals. The composition of the single crystal to be pulled can be controlled by controlling the supply amount of the raw material. As mentioned above, single crystals formed according to the present invention have good crystal properties. From the advantages described above, it is very effective to use the present invention for growing long single crystals such as compound semiconductors and oxides containing highly dissociated components.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of the device according to the present invention. FIG. 2 is a sectional view showing an apparatus used in the conventional method. In the figure, 2 is a high pressure vessel, 3 is a crucible for crystal growth, 4
Is a crucible for synthesizing a melt, 5 is a communication tube, 6 is a melt, 7 is a sealant, 9 is a crystal pulling shaft, 10 is a seed crystal, 13, 14 and 23 are heaters, 15 is a rotating shaft of an inner crucible, 16 is the inner crucible, 17 and 19
Indicates an ampule, and 17a and 19a indicate raw material supply pipes.

Claims (2)

(57) [Claims] 1. A method for growing a single crystal of a group III-V compound semiconductor by a pulling method, wherein the melt is placed in a first crucible containing a melt of the group III-V compound semiconductor. Providing a second crucible having a communication hole for inflow, and pulling a single crystal of the group III-V compound semiconductor from a melt flowing into the second crucible from the communication hole; When pulling the crystal, put it in the third crucible III
A group III element and a group V element are supplied to prepare a melt of the III-V compound semiconductor, and the prepared melt is mixed with the third melt.
Supplying the melt from a crucible to the first crucible, wherein the surface of the melt prepared in the third crucible is covered with a sealant contained in the third crucible. A method for growing a single crystal. 2. An apparatus for growing a single crystal of a group III-V compound semiconductor by a pulling method, comprising: a first crucible for containing a melt of a group III-V compound semiconductor; A second crucible provided in the crucible and having a communication hole for allowing the melt accommodated in the first crucible to flow therein; and the III-V compound from the melt flowing into the second crucible. A crystal pulling axis for pulling a semiconductor single crystal, a third crucible for mixing a group III element and a group V element to prepare a melt of the III-V compound semiconductor, A plurality of containers each containing a group III element and the group V element; and a plurality of raw material supply pipes for supplying the group III element and the group V element from the plurality of containers to the third crucible, respectively. Melting the melt prepared in the third crucible into the first crucible; And a high-pressure container accommodating the first crucible, the second crucible, and the third crucible, and the opening of the third crucible has an atmosphere in the high-pressure container. An apparatus for growing a single crystal, which is open to a single crystal.