JPS606919B2 - Method for producing Group 3-5 compound single crystal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing high quality m-V group compound single crystals.

Among the m-V group compounds, high purity potassium boronate (GaA
s) A single crystal is a semi-insulating material with a resistivity of 1 pQ or more, and has recently attracted attention as a crystal substrate for elements of ultra-high-speed integrated optoelectronic integrated circuits.

However, the additive-free ○aAs single crystal produced by the currently known high-pressure sealing and pulling method has an uneven resistance distribution within the crystal, with a resistivity of more than 1 PQ. It has been difficult to produce uniform single crystals with good reproducibility.

Reasons for this include that technology for detecting and controlling the composition of the GaAs melt has not been established, and that there is no method for measuring the quality of GaAs during melting. This invention was made in view of the above, and m-
Focusing on the fact that the current value changes depending on the composition ratio of Group V compounds, it is possible to know the composition ratio of the melt by applying a voltage to the compound melt and measuring the current value. The current value is measured while adjusting the current value, and when a predetermined value is reached, the seed crystal is pulled up, thereby obtaining a high quality m-V group single crystal having a desired resistance value.

Hereinafter, the present invention will be explained with reference to the accompanying drawings. FIG. 1 shows an example of a single crystal manufacturing apparatus, and 1 is a high-pressure container,
A rubbo 3 made of quartz, boron nitride, etc., whose outer periphery is covered with a support member 4 made of carbon material, etc. is provided inside the high-pressure vessel 1, and the rubbo 3 is supported by a rotation support shaft 6 so that it can rotate and move up and down. , a heater 2 is provided around the Lutsupo 3,
Heat and maintain the crucible 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. Then, lead wires 10 and 11 are connected to the support section 4 of Rubbo and the seed crystal pulling shaft 5, respectively. In the apparatus configured as described above, the crucible 3 is filled with predetermined amounts of group m and group V elements constituting the m-V group compound, and boron oxide (
A predetermined amount of B203) is added, the Rubbo is placed in a high-pressure container 1, the inside of the container is pressurized with an inert gas such as argon or nitrogen, and the heater 2 is heated to a temperature higher than the melting temperature of the raw material elements. melt the elements. Examples of m-V group compounds include GaAs, InP, Gap, and Gasb, and elements constituting these are used as raw materials. By the above-described heat treatment, &03 melt 8 is formed as a high-pressure sealant in the upper layer in Rubbo 3, and m-V group compound melt 7 is formed in the lower layer.

When the raw material in Rubbo is melted, the pulling shaft 5 is lowered to bring the seed crystal 9 into contact with the melt 7 in Rubbo 3. In this state, the crucible support 4 is connected via the lead wires 10 and 11.
When an AC voltage is applied from the power source 2 to the pulling shaft 5,
The crystal raw material melt 7 can be regarded as a resistor, and since Rubbo is an insulator, it can be thought of as a capacitor, and the ammeter 13 will display a current value corresponding to the resistance value of the melt 7.

The value of the current flowing through the above-mentioned electric circuit changes depending on the composition ratio of the m-V group compound melted in Rubbo.

For example, when Lubbo is heated to about 126,000 ℃, the change in the composition ratio of the Ga vessel and the change in the current value have a relationship as shown in the graph of Figure 2, where Ga is about 51.3% and As is about 48%.
The maximum current value is shown when the composition ratio is 7%, and the current value is 0.27 to 0.
When a current in the range of 3 mA (range indicated by the dotted line in the figure) flows, the composition ratio of molten GaAs in Rubbo is within the optimum range for crystal growth. This electrical signal is
Moreover, it changes depending on the temperature of the m-V group compound melt in Rubbo.

In other words, as shown in Figure 3, if the heating temperature of Rubbo is increased while the composition ratio of the Ga vessel in Rubbo is constant (Ga 50%, false 50%), the current value increases as the temperature rises. Therefore, it is considered that the change in the current value at the time of seeding reflects the temperature at which the crystal starts to solidify, and is correlated with the solidification start temperature due to the change in composition.This invention is as described above.

By measuring the current value of the melt before carrying out the crystal pulling operation, the composition ratio of the melt can be accurately determined.
If the amount of As is excessive, a single crystal having a desired composition ratio can be obtained by supplying As to the melt in the rubbo and performing a crystal pulling operation when the current reaches a predetermined value. If As is excessive, the current value will increase by reducing the pressure in the high-pressure container by a predetermined value to evaporate As from the crystal raw material melt in Rubbo. An example of an As supply device used for adjusting a molten liquid containing excess Ga is explained with reference to FIG. 4.
Connect the open □ end of the cylinder 15 to 4 in an airtight manner.

Inside the cylinder 15 is a support device 1 whose tip enters 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 28 is provided at the rear end of this support rod. Umatsutsu 15
An annular permanent magnet 19 is iron-coupled to the outer circumferential surface of the support pole, and the annular magnet 19 and the magnet 2Q at the rear end of the support pole are attracted to each other across the wall of the cylinder, and the annular magnet 9 is attached to the outer circumference of the cylinder. When the support rod 18 is slid along the cylinder, the support rod 18 is moved back and forth within the cylinder. One end of a pipe 17 is connected to the vicinity of the fixed end of the support rod 8 of the storage container 6, and the pipe 17 is bent so that its tip extends to the front of the container, so that when the support rod descends inside the cylinder, Configure it to enter. A heater 21 is provided around the container 16 to heat the inside of the container. The support rod and cylinder of the container described above are made of quartz or Pyrolithic boron nitride. The container is pulled up to the upper end and kept waiting inside the open square section 14.

A raw material is put into the Lubbo 3, the pressure and temperature are set to a predetermined value, and when the raw material in the Lubbo is melted, the seed crystal 9 is lowered and brought into contact with the crystal raw material melt 7, and the current value is measured. If it is determined that As is insufficient based on the measured current value, the annular magnet 19 aligned with the cylinder 15 is lowered, and as a result, the As storage container 16 approaches the crucible 3 and the pipe 17
The tip will be plunged into the melt 7.

Since the temperature inside the high-pressure container 1 is higher than the melting point of Aa, As
Steam is ejected from the end of the pipe 17, and As is blown into the crystal raw material solution. If the blowing amount is insufficient, the container 16 is further actively heated by the heater 21', thereby increasing the blowout amount of melon steam. The thus vaporized As is blown into the melt and reacted.
When the current value falls to a predetermined value, a crystal pulling operation is performed. If As is in excess, the pressure in the high-pressure container is reduced and $ is evaporated to maintain the pressure balance, so adjustment is easier than in the case of excess Ga.

The graph in FIG. 5 is a graph showing the relationship between the As evaporation treatment time and the current value, and as a result of measuring the current value of the melt,
Since the value was about 0.2 touch, the pressure inside the high pressure vessel was reduced to 3.
As a result of measuring the current value 1 hour and 2 hours after lowering the atmospheric pressure from 1 atm to 1 atm, it can be seen that the current value gradually increases and As gradually decreases. As described above, this invention measures the current value of the melt before performing the crystal pulling operation, and if a current value corresponding to the composition ratio within a predetermined range cannot be obtained, as described above, As is supplied or Alternatively, since the crystal is pulled after adjusting the desired composition ratio by evaporation, high-quality single-line crystals of Yama-V group compounds can be obtained with good reproducibility. It can also be applied to the production of m-V group compound single crystals such as.

- Next, examples of the present invention will be described.

In a single crystal manufacturing apparatus having a structure as shown in Fig. 1, a rubbo made of Pyrolithic boron nitride with an inner diameter of 100 ribs and a depth of 100 yen is coated with 500 g of gallium, 550 g of phosphorus, and a water content of 1.
After putting 180 tons of 0Q blood boron oxide, placing it in a high-pressure container and pressurizing argon gas to make it about 5 pressures, heat the rubbo to 130,000 degrees to create a layer of 03 molten liquid on the top and a layer of molten GaVs on the bottom. When the liquid layer is formed, the temperature of the crucible is increased to 12
The pressure inside the container was lowered to 2 p atm, the seed crystal was brought into contact with the GaAs melt, and an AC voltage of 15 V was applied.

Since the current value at this time was 0.3, the vaporized gunpowder was blown into the melt for 30 minutes using the As supply device shown in FIG. Since the temperature had dropped to several hA, the seed crystal was brought into contact with the molten liquid of the Ga vessel, and a pulling operation was performed at a speed of 10 sails/hour to obtain a Ga pine single crystal with a diameter of about 5 ribs and a length of about 10 sails. Ta. The graph of FIG. 6 shows the results of examining the resistance distribution in the crystal growth direction using this single crystal as a vertically divided wafer. In the graph, curve a is the resistance value of the crystal obtained by the method of the present invention, which is 1080 in the entire crystal growth direction.
・It showed a stable high resistance value that was higher than that of the skin. For reference, the resistance value in the growth direction of a vertically split single crystal wafer manufactured without performing the As blowing operation is as shown in curve b.
It was non-uniform and showed a tendency of excessive Ga at the crystal edges, and decreased rapidly.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a single crystal manufacturing apparatus for carrying out the method of the present invention, and FIG. 2 is a graph showing an example of the relationship between Ga lees composition ratio and current value. FIG. 3 is a graph showing the relationship between the temperature of the GaAs melt and the current value, FIG. 4 is a cross-sectional view showing an example of an As supply device, and FIG.
The figure is a graph showing the relationship between the transpiration state of As and the current value. 6th
The figure is a resistance value distribution diagram of a Ga carrier single crystal obtained by the method of the present invention. In the figure, 1 is a high pressure vessel, 2 is a heater,
3 is Rubbo, 5 is the pulling axis, 7 is the crystal raw material melt, 9
indicates a seed crystal/crystal, and 12 indicates a power source. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. A method for producing III-V group compound crystals by a pulling method, in which an alternating current voltage is applied to a III-V group compound melt and the current value is in the range of 0.27 to 0.3 mA. 1. A method for producing a III-V compound crystal, which comprises adjusting the composition ratio of the III-V compound in the melt and pulling the seed crystal. 2. The manufacturing method according to claim 1, wherein the III-V group compound is a potassium arsenic compound.