JPS606920B2 - Gallium arsenide single crystal production equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for producing high-quality semi-insulating gallium arsenide GaAs single crystals, and more specifically, the present invention relates to an apparatus for producing high-quality semi-insulating gallium arsenide GaAs single crystals, and more specifically, a production apparatus for producing GaAs single crystals equipped with means for blowing steam into a raw material melt. Regarding manufacturing equipment.

Among m-V group compounds, GaAs has a high electron mobility and is being widely used as a material for high-speed integrated circuits, optics, and electronic devices.

GaAS is attracting attention because of its high quality G.
A: It has high insulation properties with a false resistivity of 1 or more, it has few defects in the crystal and has a uniform distribution, and it is easy to manufacture large wafers. . A method for manufacturing GaAs single crystals that satisfies such requirements is the liquid confinement pulling method (LEC method).
This liquid sealing pulling method includes a low pressure sealing pulling method and a high pressure sealing pulling method. The low-pressure sealing pulling method uses a GaAs polycrystal containing impurities such as Si, which is prepared in advance by a boat growth method, as a single crystal as a raw material, and therefore requires the addition of chromium to make it semi-insulating, which is not preferable. In addition, the high-pressure sealed pulling method that directly synthesizes the raw materials does not require the addition of chromium, but the raw material Ga and the sealant &03
When put into a crucible and heated under high pressure for synthesis, a large amount of As, which has a low vapor pressure, transpires. Therefore, Ga of the desired composition ratio
Although the amount of lees added is increased to obtain As molten liquid,
The amount of false transpiration varies depending on the conditions, and the amount of Ga in the melt
Due to variations in the vessel composition ratio, it has been difficult to obtain high-quality additive-free (undoved) Ca whistle single crystals with good reproducibility. An object of the present invention is to provide a single crystal manufacturing apparatus capable of manufacturing a high quality semi-insulating additive-free Ga common single crystal with good reproducibility.

Therefore, in the single crystal manufacturing apparatus according to the present invention,
Equipped with a means for blowing melon steam into the crystal raw material melt in Rubbo, if a shortage of AS is found during raw material synthesis, As vapor is directly blown into the raw material melt to adjust the GaAs composition ratio to a predetermined value. After that, crystal growth is performed.

Therefore, high quality GaAs single crystals can always be obtained with good reproducibility. First, the method proposed by the present inventors for measuring the GaAs composition ratio in the crystal raw material melt will be explained with reference to FIG. A covered rubbo 3 made of quartz, boron nitride, etc. is provided, and this rubbo 3 is rotatably supported by a rotation support shaft 6.A heater 2 is placed around the crucible 3.
is installed to heat and maintain Rubbo at a predetermined temperature.

A conductive pulling shaft 5 with a seed crystal 9 attached to the lower end is provided on the upper part of Rubbo 3, and this pulling shaft is configured to rotate and move up and down. Lead wires 10 and 11 are connected to the Rubbo support member 4 and the seed crystal pulling shaft 5.
Connect each. Inside Rubbo 3, there is G as a crystal material.
A, As, and a predetermined amount of boron oxide B03 as a high-pressure sealant are put in, the inside of the container is pressurized with an inert gas, and heated with a heater to a temperature higher than the melting point of the raw material. When the raw material in the Luppo melts, the pulling shaft is removed. 5 is lowered to bring the seed crystal 9 into contact with the raw material melt 7 in the rubbo 3. In this state, when an AC voltage is applied from the power supply 12 to the crucible support 4 and the pulling shaft 5 via the lead wires 10 and 11, the GaAs melt is treated as a resistor, and since the crucible is an insulator, it becomes a capacitor. By configuring this, the ammeter 13 displays a current value corresponding to the resistance value of the raw material melt.

The above current value changes depending on the composition ratio of GaAs melted in the crucible.

As an example, when Rubbo is heated to about 126,000 G
The relationship between the composition ratio of aAs and the current value is as shown in Figure 2.
The maximum current value is exhibited when the composition ratio is approximately 51.3% Ga and 48.7% As, and as the number of ships increases beyond that, the current value rapidly decreases. Normally, the composition ratio of Ga and As in the melt to obtain a high-quality single crystal is said to be in the range of 50%±0.2, and the current value can be adjusted to 0.2 by adjusting the composition ratio of GaAs in the melt. When a range of 27 to 0.3 hA (range indicated by the dotted line in the figure) is specified, a high quality GaAs single crystal can be obtained with good reproducibility by performing a crystal pulling operation. FIG. 3 is a cross-sectional view of the single crystal manufacturing apparatus shown in FIG. 1, which is equipped with an As supply means according to the present invention. Connect the ends airtight.

Inside the cylinder 15 is a support rod 1 whose tip protrudes into the high pressure container 1.
8, and a phosphorus storage container 16 is fixed at the tip of the support rod.
A permanent magnet 20 is provided at the rear end of this support rod. Umatsutsu 15
An annular permanent magnet 19 is attached to the outer circumferential surface of the support rod, and this permanent magnet 19 and the magnet 20 at the rear end of the support rod are attracted to each other across the wall of the cylinder, and the permanent magnet 19 is moved along the outer circumference of the cylinder. When the support rod 18 is slid, the support rod 18 also moves back and forth within the cylinder. The support rod may be held and slid by other methods. One end of a pipe 17 is connected to the vicinity of the fixed end of the support rod of the container 16, and the pipe 17 is bent so that its tip extends toward the front of the container, so that when the support rod descends inside the blind cylinder, the raw material melt in the crucible 3 7.
A heater 21 is provided on the circumferential surface of the container to heat the inside of the container. The container, support rod, and tube described above are made of quartz or Pyrolitec boron nitride. To explain how to use the single crystal manufacturing apparatus having such a configuration, As is loaded into the storage container 16 in advance, and the support rod 18 is pulled up to the upper end by the annular magnet 19 to place the container into the entrance part 14. Make it standby.

Ga, As, and B203 are put into the Lubbo 3, maintaining the predetermined pressure and temperature, and when the raw materials in the Lubbo are melted, the seed crystal 9 is lowered, brought into contact with the GaAs melt 7, and the current value is measured. If it is determined from the measured current value that As is insufficient, the annular magnet 19 aligned with the blind cylinder 15 is lowered.

As a result, the container 16 approaches the crucible 3, and the tip of the pipe 17 plunges into the GaAs melt 7 inside the crucible 3. Because the temperature inside the high-pressure vessel 1 is higher than the melting point of the ship,
As vapor is ejected from the tip of the pipe, and is blown into the GaAs melt. If the amount of blown steam is insufficient, the amount of ship steam blown out is increased by further actively heating the container 16 from the heater 21'. When the GaAs melt in Rubbo is adjusted to a predetermined composition ratio, the heating of the container 16 is stopped, the support rod is pulled up, the container 16 is placed on standby in the closing part 14, and the seed crystal 9 is rotated and pulled up. Normal single crystal production is carried out by When a single crystal is produced by rotating and pulling a seed crystal in contact with a Ga vessel melt, the composition ratio of GaAs in the raw material melt has a large effect on the quality of the produced single crystal.

In particular, As has a lower evaporation temperature than Ga, and when the raw materials are synthesized under high pressure, if the conditions change even slightly, the Ga carrier composition ratio of the synthesized melt will change slightly, resulting in GaAs having the desired composition ratio. It is difficult to synthesize a melt with good reproducibility. However, with the present invention, it is possible to supply As to the Ga vessel melt in the high-pressure vessel, and the composition ratio of the melt is adjusted before the crystal pulling operation, making it possible to obtain high-quality CaAs single crystals with good reproducibility. Furthermore, during raw material synthesis or crystal pulling, As is injected into the high-pressure vessel from the pipe connected to the melon storage vessel, forming the atmosphere that the ship contains in large quantities. Due to the presence of the pine tree, A
It suppresses transpiration of s and contributes to improving the quality of single crystals. Note that the method for measuring the composition ratio of the GaAs melt described in the specification is just one example, and based on the results obtained by other measurement methods, As is supplied to the crystal raw material melt using the apparatus of the present invention, Needless to say, it is possible to manufacture single crystals.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of a single crystal manufacturing apparatus equipped with a means for measuring the GaAs composition ratio in the melt, Fig. 2 is a graph showing an example of the relationship between the GaAs composition ratio and the current value, and Fig. 3 FIG. 2 is an enlarged cross-sectional view of the feed means of the single crystal manufacturing apparatus according to the present invention. In the figure, 1 is a high-pressure vessel, 2 is a heater, 3 is a receptacle, 5 is a pulling shaft, 6 is a seed crystal, 7 is a Ga pseudo melt, 13 is an opening, 14 is a cylinder, 15 is an As storage container, 16 is a pipe, 17 is a support rod, 18 and 19 are magnets, and 20 is a heater. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A rotating crucible that is heated by a heater to melt raw materials in a high-pressure container, and a pulling shaft that can rotate and move up and down with its lower end facing above the crucible and a seed crystal attached to the lower end,
Once the raw material in the crucible is melted, the pulling shaft is lowered,
In a single crystal manufacturing apparatus that rotates and pulls a seed crystal at the lower end in contact with the melt in the crucible, a blind tube is provided with the open end airtightly connected to an opening opened in the upper side wall of the high pressure container; A support rod whose tip extends into the high-pressure container is housed in the blind tube, and a means for sliding the support rod along the blind tube is provided on the outer periphery of the blind tube and the support rod, and a means for sliding the support rod along the blind tube is provided. Gallium arsenide crystal production characterized in that an arsenic storage container having a heater provided on its circumferential surface is fixed to the tip of the support rod, and a pipe is provided protruding from the arsenic storage container with its tip directed toward the crucible. Device.