KR940009942B1 - Method for monocrystaline growth of dissociative compound semiconductors - Google Patents

Abstract

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Description

High dissociation compound semiconductor single crystal growth method and apparatus

1 is a schematic cross-sectional view showing an example of an apparatus for practicing the first invention.

2 is a schematic cross-sectional view showing an example of an apparatus for implementing the conventional high dissociation-pressure compound semiconductor single crystal growth method.

* Explanation of symbols for main parts of the drawings

1: Outer container 2: Sealed container

4: upper axis posbaa 5: lower axis posbaa

7: Raw material melt container (crucible) 8, 8 ': Heating mechanism (heater)

9: high dissociation pressure component gas pressure control furnace 16: raw material melt

23, 26: outer shaft outer tube 24: first low-cell

27: low cell load 29: second low cell

The present invention relates to a high dissociation compound compound single crystal growth method and apparatus for performing pressure control of the high dissociation pressure component gas.

An example of the method for estimating the high dissociation compound semiconductor single crystal is a method using the apparatus shown in FIG.

This method will be described in detail with reference to FIG.

The growth apparatus of the high dissociation-pressure compound semiconductor single crystal of FIG. 2 includes a sealed container 2 composed of a sealed outer container 1, a sealed container upper body 2a housed therein, and a lower container 2b of the sealed container. And a compression shaft (3) provided with a flange (3a) at the upper end and a buffer mechanism (3b) in the middle so as to penetrate the outer container (1) in an airtight manner so as to be able to move up and down. It extends into the sealing container 2 through the upper walls of the outer container 1 and the sealing container upper body 2a, and is lowered like the force bar 4 which is vertically rotatable and rotatable. A lower shaft force bar 5 extending through the lower wall of the outer container 1 and the sealing container body 2b from the inside of the sealing container 2, and capable of moving up and down and rotating; On the outside of the sealing container 2, a susceptor 6 provided at the upper end of the osbar 5, a raw material melt container (crucible) 7 blocked by the susceptor 6, and a sealing container 2; Contact with the high dissociation pressure component gas pressure control passage 9 installed in the four-row heaters 8, 8 'and the sealed container 2, the sealed container upper body 2, and the upper shaft force bar 4; In contact with the sliding part, the sealing container body 2b, and the lower shaft force bar 5, respectively, the liquid sealing agent 10, 10 'and the upper side of the outer container 1 are provided in the sealing container 2, respectively. A transparent rod 13 is hermetically inserted. In addition, the sealing container upper body 2a and the sealing container 2b are joined by the joining parts 2c and 2d, and the sealing container 2 is sealed.

Reference numeral 9a denotes a high dissociation-pressure component solid As.

When the compound semiconductor single crystal is grown using this apparatus, firstly, Group III metal (Ga), which is a raw material, is introduced into the crucible (7), and a high dissociation-pressure component solid (As) is placed at the bottom of the sealing container (2). The outer container 1 and the sealed container 2 in a vacuum state, and then the heaters 8 and 8 'are heated to heat the sealed container 2 in which the liquid sealants 10 and 19' are melted. ) Is isolated from the outer container 1, and the inside of the outer container 1 is set to a predetermined pressure as an inert gas, and the heater 8 'is heated again to evaporate the high dissociation pressure component solid, and further, the high dissociation pressure component gas pressure. The control furnace 9 is adjusted to fill the sealed container 2 with the high dissociation pressure component gas (As) at a predetermined pressure, and the high dissociation pressure component gas reacts with the Group III metal in the crucible (7) to melt the raw material (GaAs). ) 16, and in this state, the upper shaft force bar 4 is lowered, so that the seed crystal (GaAs) 17 is immersed in the raw material melt 16, and the upper shaft force bar (4). To I, while it is possible, by pulling as (引 上) to obtain a compound semiconductor single crystal (GaAs).

At this time, the composition control of the raw material melt is performed by temperature control of the high dissociation component gas pressure control passage 9.

However, when the compound semiconductor single crystal is grown by the single crystal pulling method which controls the pressure of the high dissociation pressure component gas as described above, the composition control becomes important when making the raw material melt by direct synthesis. Since the composition control of the melt was carried out by temperature control of the high dissociation component gas pressure control furnace, since the composition ratio was not accurately determined, many experiments were required in the process to know the optimum high dissociation component gas pressure control temperature. there was.

In addition, in the process of performing direct synthesis, the end of the synthesis cannot be confirmed, and the change operation is performed after the holding time deemed appropriate. Therefore, improvement is necessary so that the transfer can be carried out after the completion of the synthesis is confirmed. It is becoming.

In order to improve the above state, the weight of the total raw material melt container including the raw material melt container (crucible) support shaft may be measured, the exact weight of the raw material melt may be measured, and precise composition control of the raw material melt may be performed. Since the weight of the group III element in the crucible is already known in order to accurately measure the raw material melt, it is good if the weight change due to the high dissociation pressure component dissolved by the reaction can be accurately measured.

However, in the above-described conventional example shown in FIG. 2, since the lower cell force bar 5 is not provided with a low cell, the weight of the raw material melt cannot be measured, so that precise composition control cannot be performed. there was.

Therefore, although it is conceivable to attach the low cell to the lower axis force bar 5, even if the low cell is attached to the lower axis force bar 5, the structure of the pulling device is derived from the inside of the sealing container 2 There is a problem that the measurement of the low cell is difficult due to the pressure difference between the outer container 1.

That is, in order to seal the high dissociation-pressure component gas in the sealing container 2, the lower shaft force bar 5 receives a force equal to the pressure difference between the internal pressure of the sealing container 2 and the internal pressure of the outer container 1. .

For this reason, it becomes difficult to detect the exact total weight of the crucible, and furthermore, it becomes difficult to perform accurate composition control of the raw material melt 16.

SUMMARY OF THE INVENTION In order to solve the above problems with the conventional high dissociation compound semiconductor single crystal growth method and apparatus, the present invention provides precise composition control of the raw material melt while ensuring the airtightness of the sealed container. In the second invention, a high dissociable compound semiconductor single crystal growth method capable of providing a high dissociation compound semiconductor single crystal growth apparatus capable of precise composition control of a raw material melt while ensuring airtightness of a sealed container is provided. do.

In order to achieve the above object, the present invention has the following configuration.

That is, in the first invention, the upper shaft force inserted into the sealing container from the top of the sealing container in which the compound semiconductor single crystal was delivered in the sealing container while controlling the pressure of the high dissociation pressure component gas sealed in the heat-sealing container. A method for producing a compound semiconductor single crystal by the Czoc hralski process, which is pulled up by a bar, comprising a first low cell attached to a lower shaft force bar supporting a raw material melt container in the sealed container, and an electric seal. The weight change of the raw material melt in the above-mentioned raw material melt container is measured by the second low cell installed in the low cell rod extending into the sealed container by airtightly and moving through the wall of the container. The composition of the raw material melt is controlled by calculating the weight of the raw material melt directly synthesized by the present invention. In the second invention, the external container and the external container The upper and lower shaft force bars installed in the sealed container through the upper and lower walls of the outer container and the sealed container, and rotatably and hermetically penetrating through the sealed container, respectively. A raw cell rod, which is movably and airtightly penetrated through the walls of the outer container and the sealed container, is extended to the inside of the sealed container, a raw material melt container supported by the lower shaft force bar in the sealed container; A heating mechanism provided outside the sealed container so as to be heatable, the high dissociation component gas pressure control furnace provided in the sealed container, the first low cell connected to the lower shaft force bar, and the low A second low cell connected to the decel rod is constructed.

In the first invention, the first low cell attached to the lower shaft force bar and the second low cell attached to the low cell rod which extends in the sealed container through the airtight and movable walls of the sealed container in an airtight and movable manner. By measuring the weight change of the raw material melt, calculating the weight of the raw material melt directly synthesized by the measured weight change, and automatically controlling the composition of the raw material melt, the pressure difference between the internal pressure of the sealed container and the internal pressure of the external container It solves the adverse effect on the measurement accuracy of the total raw material melt weight, enabling accurate automatic composition control of the raw material melt.

In the second invention, the first row cell attached to the lower shaft force bar and the second row attached to the row cell rod extending into the sealed container hermetically and mobilely through the walls of the outer container and the sealed container. The weight change of the raw material melt is measured by the decell, and the weight of the directly synthesized raw material melt is accurately calculated based on this weight change, and the raw material melt composition is automatically controlled by adjusting the temperature by controlling the high dissociation pressure component gas pressure. It is possible to carry out precise composition control of.

In the present embodiment, in view of the situation of the conventional method described above, the first low-cell force bar 5 includes the first low cell 24 and the first low-cell force bar 5 is provided. In addition, the lower cell of the sealing container 2 is airtightly and movably penetrated so that the low cell rod 27 is provided, and the low cell cell 27 is provided with the second low cell 29, thereby providing raw materials. The exact weight of the melt was measured to enable accurate composition control of the raw material melt 16.

In the present embodiment, when the weight of the raw material melt is measured only by using the first low cell 24, the internal pressure of the sealing container 2 and the internal pressure of the external container 1 are measured on the lower shaft force bar 5. Since a force equal to the pressure difference between and is applied, in order to prevent the weighing of the raw material melt from being inaccurate, the above-described low cell force bar 5 and the lower cell shell rod 27 and the second low cell 29 were provided. .

That is, the low cell rod 27 having the pressure difference between the internal pressure of the sealed container 2 and the pressure in the outer container 1 at Δp, the radius of the lower axis force bar 5 at R ₁ , and the lower part of the sealed container 2 is provided. The radius of R ₂ , the weight detected by the first low cell 24 attached to the lower axis force bar 5, W ₁ , the true weight W ₁ , the second low cell attached to the low cell rod 27 When the weight detected by (29) is W ₂ , and the true weight is W ₂ , the internal pressure of the sealed container 2 and the internal pressure of the external container 1 are applied to the first and second door cells 12 and 24. As it affects the fluctuation of the pressure difference between

W ₁ = W1 + Δp × π × R ² ₁

W ₂ = W2-Δp × π × R ² ₂

from

×Δp=(W₂-W2)÷R² ₂

× Δp = (W ₂ -W2) ÷ R ² ₂

1W1 = W _1- (W ₂ -W2) × R ² ₁ ÷ R ² ₂

From here,

R ₁ = k × R ₂

If W2 is constant,

W ₁ = W _1- (W ₂ -W2) × k ²

W ₁ = W ₁ -k ² × W _{2 + C}

The correct crucible weight is obtained. (Where _C is an integer)

In addition, in order to determine the total weight of the crucible, a lower vessel cell 27 is inserted in the lower part of the inside of the crucible, and instead of installing the second lower cell 29 in the outer cell rod 27, a sealed container ( 2) A lower cell rod (same as the second cell shell 29) may be installed in the lower cell rod by inserting a lower cell rod (same as the lower cell rod 27) in the upper part. In the,

W1 = W ₁ + (W ₂ -W2) × k ²

W1 = W ₁ + k ² × W ² + c '

(Where c 'is an integer)

Next, in order to implement this first invention, the method of the first invention will be described based on the apparatus shown in FIG.

In addition, in the apparatus of this embodiment, the same code | symbol is used for the same part as a conventional example, and the description is abbreviate | omitted.

In the apparatus of the present embodiment, the first low cell 24 is installed in the lower axis force bar 5, and the new low cell rod 27 is added by inserting it into the lower part of the sealing container 2, and the low cell The point at which the second low cell 29 is provided at 27 is different from the high dissociation compound semiconductor single crystal growth apparatus shown in FIG. 2 of the conventional example.

The upper shaft force bar 4, the lower shaft force bar 5, and the lower cell rod 27 have different outer diameters in FIG. 1, but they may have the same diameter.

In the present embodiment, the flange 3a is provided on the upper portion, and the buffer mechanism 3b is provided in the middle, and the compression shaft 3 is provided by penetrating the outer container 1 up and down in an airtight manner. The flange 3a of the compression shaft 3 is joined to the bottom of the sealing container 2.

In the compression shaft 3 and the shock absorbing mechanism 3b, a lower shaft outer pulltube 23 fitted to the lower shaft force bar 5 is inserted to be capable of vertically sliding and sliding rotation, and the lower shaft outer pull tube. The rotary drive mechanism (not shown) is attached to the web 23.

A second low cell 24 is attached to the lower end of the lower axis POSBAR 5 and the lower axis outer full tube 23, and the first low cell 24 is connected to the computer via an A / D converter 25. 15) is connected.

Moreover, the lower shaft outer pull tube 26 is attached to the bottom of the outer container 1 by airtightly and vertically sealing in the shape which hanged down.

The lower cell outer tub 26 has a low cell rod 27 inserted therein. The low cell rod 27 extends into the sealed container 2 through the outer container 1, the flange 3a, and the lower body 2b of the sealed container so as to be movable up and down.

On the bottom inner surface of the lower body 2b of the sealed container, a container 28 is disposed at the contact portion between the sealed container body 2b and the low cell rod 27 and holds a liquid sealant 10 "therein. A second lower cell 29 is attached to the lower end of the lower shaft outer pull tube 26 and the lower cell rod 27.

The computer 15 is connected to the second low cell 29 via the A / D converter 30. Then, the weight change of the raw material melt 16 is measured using the first low cell 24 and the second low cell 29.

That is, the output signals from the first and second loudspeakers 24 and 29 are converted into digital signals by the A / D converters 25 and 30 and read-in to the computer 15. -in), numerical calculation is performed, the correct total crucible weight is calculated, and the temperature of the high dissociation pressure component gas pressure control furnace 9 is adjusted based on this value to automatically control the raw material melt composition.

Using a high dissociation compound semiconductor single crystal growth apparatus having the structure shown in FIG. 1, the GaAs single crystal was pulled up while controlling the vapor pressure of As.

The growth conditions were set at pulling speed of 5 mm / h, crystal rotation of 5 rpm, and crucible rotation of 5 rpm.

The obtained crystal was a single crystal having a diameter of 80 mm and a length of 100 mm, and was a good thing having high uniformity.

In the conventional high dissociation compound semiconductor crystal growth method and apparatus for performing pressure control of the high dissociation pressure component gas, it is difficult to perform composition control, but according to the present embodiment, a uniform single crystal having a composition control is obtained and furthermore, The end point of the direct synthesis of the melt 16 can be confirmed, and furthermore, since the additional cell shell rod 27 does not require rotation, the cost is lowered.

In the above-described result, as in the first low cell 24 attached to the lower shaft force bar 5 through the lower shaft outer tubing 23, the lower cell rod 27 through the lower shaft outer tubing 26 added again. The second low cell 29 may be attached to the c) to enable accurate measurement of the weight of the raw material melt.

As a method of performing the above-described arithmetic processing, there is a method by the computer 15, a method by an electric circuit, and the like.

Further, precise composition control can be easily performed by performing automatic composition control based on the weight of the accurate raw material melt thus obtained.

Next, the second invention will be described. As an embodiment of the second invention, an implementation by the apparatus shown in FIG. 1 is already described. According to the embodiment of the present invention, the weight change of the raw material melt is measured, and the weight of the directly synthesized raw material melt is accurately calculated based on the weight change, and the high dissociation component gas pressure control is used to adjust the temperature to accurately and automatically control the raw material melt composition. can do.

In addition, in the above-mentioned embodiment, although the lower cell rod 27 was inserted in the lower part in the sealing container 2, and the second lower cell 29 was attached to the lower cell rod 27, the present invention is not limited thereto. A plurality of low cell rods may be inserted into the lower part of the sealing container 2, and the low cell cells may be attached to each of the low cell cells, and instead of the above-mentioned low cell rods 27 and the second low cell 29. From the upper side of the sealing container 2, one or two or more row cell rods are inserted into the upper part of the sealing container 2, and the second, third,... A lower cell rod may be attached, and one or two or more lower cell rods are inserted into the sealing container 2 from the side of the sealing container 2, and the second, third, … The low cell rod may be attached.

According to the first aspect of the present invention, a raw material is formed by a first low cell attached to a lower shaft force bar and a second low cell mounted on a low cell rod which extends into the sealed container by airtightly and movably penetrating the walls of the sealed container. The weight change of the melt can be measured, and the weight of the raw material melt synthesized directly from the measured weight change can be used to automatically check the composition of the raw material melt, thereby making the total raw material due to the pressure difference in the sealed container and the external container. The adverse effect on the measurement accuracy () of the melt weight can be eliminated, so that the precise composition control of the raw material melt can be easily performed, and the end point of the direct synthesis of the raw material melt can be confirmed.

In addition, according to the second invention, the first low cell attached to the lower shaft force bar and the second low cell installed in the low cell rod which extends into the sealed container through the airtight and movable airtightness of the sealing container. By measuring the weight change of the raw material melt, accurately calculating the weight of the directly synthesized raw material melt on the basis of the weight change, and controlling the temperature by the high dissociation pressure component gas pressure control, it is possible to automatically and accurately control the raw material melt composition easily and easily. In addition, it is possible to confirm the end point of the direct synthesis of the raw material melt.

Claims (2)

While controlling the pressure of the high dissociation-pressure component gas sealed in the heat-sealing container 2, in the sealing container 2 from the top of the sealing container 2 in which the compound semiconductor single crystal was delivered in the above-mentioned sealing container 2. A method for producing a compound semiconductor single crystal by the Czochralski method pulled by the inserted upper shaft force bar (4), the lower shaft force bar (5) for supporting the raw material melt container (7) in the sealed container (2). A second low cell (29) mounted on the first low cell (24) attached to the first low cell (27) and the low cell rod (27) extending through the airtight and moving wall of the sealed container (2). To measure the weight change of the raw material melt 16 in the raw material melt container 7 described above, and calculate the weight of the raw material melt 16 directly synthesized by the measured weight change to control the composition of the raw material melt. High dissociation compound semiconductor stage, characterized in that How to grow forward. The outer container 1, the sealed container 2 installed in the outer container, and the upper wall and the lower wall of the outer container 1 and the sealed container 2, respectively, which vertically and rotatably penetrate through the seal, are sealed. The sealed container is movable and airtightly penetrated through the upper shaft force bar 4 and the lower shaft force bar 5 extending into the container, and the walls of the outer container 1 and the sealed container 2 that are moved. (2) the lower cell rod 27 extending into the interior, the raw material melt container 7 supported by the lower shaft force bar 5 in the sealed container 2, and the sealed container ( 2) a heating mechanism (8) and (8 ') provided outside the sealed container, a high dissociation pressure component gas pressure control path (9) provided in the sealed container (2), and an electric lower shaft force. A first low cell 24 connected to the bar 5 and a second low cell 29 connected to the above-described low cell rod 27. High dissociation compound semiconductor single crystal growth apparatus.

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