JPH06275532A - Manufacture of iii-v compound semiconductor - Google Patents

Abstract

PURPOSE:To improve the productivity of a semiconductor without lowering the synthesizing temperature by separately arranging a sealed boat filled up with a raw material of a group III element and another raw material of a group V element and passing an introducing pipe for introducing the vapor of the group V element through the partition between the boat and the raw material of the group V element, and then, controlling the temperature of an area containing the partition, entrance of the introducing pipe, and group V element to a value lower than a specific value. CONSTITUTION:A raw material 9 of a group V element vaporized by sublimation enters an introducing pipe 5 from its entrance and reacts to another raw material 2 of a group III element in a boat 1, resulting in the solution of a III-V compound semiconductor. When the solution is solidified by gradually lowering the temperature of the solution from one end of the boat 1, polycrystalline grains or single crystal of the semiconductor is obtained. At this time, the temperature of an area containing a partition 6, the entrance of the pipe 5, and raw material of the group V element is controlled to <1,050 deg.C so as to suppress the reaction between the raw material of the group V element and a sealed quartz tube. Therefore, the risk of the occurrence of such a case that SiO is introduced to the boat 1 through the pipe 5 and gets mixed in the semiconductor can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses a quartz tube III
The present invention relates to a method for manufacturing a group V compound semiconductor.

[0002]

2. Description of the Related Art III-V group compound semiconductors such as GaP and GaAs are used as materials for optical devices such as laser diodes and light emitting diodes and high speed devices such as HEMTs. In most of these III-V group compound semiconductors, a group III element and a group V element are separately arranged in a quartz sealed tube and vacuum-sealed, and a method such as GF method, Bridgman method, or zone melting method is used. It is manufactured by directly synthesizing in. However, in these methods, as the boat for filling the group III element, a boat type or a cylindrical type boat having a slit for introducing the group V element is used, and the reaction between the quartz sealed tube and the group V element, for example, P In the case of, P ₄ (g) + 4SiO ₂ (s) → 4SiO (g) + PO (g) 4SiO (g) + P ₄ (g) → Si (s) + PO (g) (1) (g): gas, (S): Solid In the case of As, As ₄ (g) + 4SiO ₂ (s) → 4SiO (g) + AsO (g) 4SiO (g) + As ₄ (g) → Si (s) + AsO (g) (2) ), SiO directly penetrated into the boat and was synthesized.
Si in III-V compound semiconductor polycrystal or single crystal
Is mixed in. Si is an impurity that needs to be reduced because it easily serves as a donor in the III-V compound semiconductor and affects the control of the carrier concentration in the subsequent single crystal pulling and epitaxial growth. (1),
The reaction between the sealed quartz tube and the group V element represented by the formula (2) is likely to be promoted at a temperature of 1050 ° C. or higher at which the viscosity of quartz is lowered. Therefore, conventionally, in order to suppress the mixing of Si, the synthesis temperature and the vapor pressure of the group V element at the time of manufacturing are lowered. However, when the synthesis temperature and the vapor pressure of the group V element are lowered, the synthesis time becomes long, and the excess of the group III element is likely to be formed, resulting in a drawback that productivity is deteriorated.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, to improve productivity without lowering the synthesis temperature, and to improve S
An object of the present invention is to provide a method for producing a III-V group compound semiconductor in which i contamination is suppressed.

[0004]

In order to achieve the above-mentioned object, the present invention provides a closed boat in which a group III element raw material is filled in a quartz sealed tube and a group V element raw material, which are separately arranged. A partition plate slightly smaller than the inner diameter of the quartz sealed tube is placed between the group V element raw materials, and an introduction pipe for introducing the vapor of the group V element is extended from one end of the boat and installed through the partition plate. The present invention provides a method for producing a III-V group compound semiconductor, characterized in that the temperature in the range where the partition plate, the inlet of the introduction pipe and the group V element raw material are placed is less than 1050 ° C.

[0005]

In the present invention, the closed boat for filling the group III element raw material is a cylindrical boat made of graphite, and one end thereof is provided with a mounting hole for an introduction pipe for introducing the vapor of the group V element. The introduction tube is a cylindrical tube made of graphite,
It is important to have an inner diameter such that the vapor of the group V element does not solidify in the tube and cause clogging, and an inner diameter of 5 mm or more is preferable. The partition plate installed between the boat and the group V element raw material is
It is made of opaque quartz, has an outer diameter slightly smaller than the inner diameter of a quartz sealed tube in which these are put, and has a hole for penetrating the introduction tube. The difference between the outer diameter of the partition plate and the inner diameter of the quartz sealed tube and the difference between the outer diameter of the hole of the partition plate and the outer diameter of the introduction tube are each preferably within 1 mm. Further, when the synthesis temperature is a high temperature at which quartz is easily softened and the boat is heated to a high temperature by high-frequency induction heating, an opaque quartz heat shield tube covering the boat is used to prevent the quartz sealed tube from being broken. Set up. Then, a group V element raw material is put into the quartz sealed tube, the group III element raw material is filled in the boat, one of the introduction pipes is attached to a hole provided at one end of the boat, and the other of the introduction pipes is attached. First, the partition plate is attached, and when the heat shield tube is required, the boat is inserted thereinto, and in this state, the boat is put into the quartz sealed tube and vacuumed to be sealed. The sealed quartz sealed tube is placed in a furnace using a high-pressure container, and several tens of kg of inert gas is used in the furnace in order to prevent the quartz sealed tube from bursting due to an increase in vapor pressure of the group V element raw material.
Pressurize to / cm ³ . After that, the boat is heated to the synthesis temperature, and the temperature is raised so that the group V element raw material is gradually sublimated.

The group V element raw material which has been sublimated into vapor is
The melt of the III-V group compound semiconductor is synthesized by reacting with the group III element raw material filled in the boat from the inlet of the introduction tube through the tube. Then, by gradually lowering the temperature from one end of the boat to solidify the melt, III-V
Group compound semiconductor polycrystals or single crystals are produced. At this time, by controlling the temperature of the partition plate, the inlet of the introduction pipe, and the region in which the group V element raw material is present to less than 1050 ° C., the reaction represented by the above formula (1) or (2) hardly occurs. Therefore, the possibility that SiO enters the boat through the introduction pipe and mixes Si is reduced. Further, between the partition plate and the quartz sealing tube and between the partition plate and the introduction tube,
Since it is not completely sealed and there is a narrow gap, the group V element raw material penetrates through the gap to the side where the boat is placed, and the quartz seal in the portion heated to high temperature The reaction represented by the formula (1) or (2) occurs on the inner surface of the tube or the surface of the heat shield tube. However, while the group V element raw material was sublimated, the internal pressure on the side where the group V element raw material was placed was slightly higher than the internal pressure on the side where the boat was placed, with the partition plate as a boundary. There is little possibility that SiO will enter the side where the group V element raw material is placed, and there is little concern that Si will be mixed.

[0007]

An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic diagram of GaP synthesis by a horizontal zone melting method using high frequency induction heating and a heating temperature distribution diagram in a furnace. In the figure, outer diameter 48 mm, inner diameter 4
On a boat 1 made of graphite with a length of 0 mm and a length of about 700 mm
About 2 kg of Ga2, which is a group III element raw material, is filled and the outer diameter is 4
8mm, 10mm thick graphite caps 3, 4
Seal both ends of the boat 1 with. Further, the cap 4 is provided with a through hole having an inner diameter of 12 mm, and the hole has an outer diameter of 12 m.
A graphite introducing tube 5 having a diameter of m, an inner diameter of 8 mm and a length of 200 mm is fitted. And outer diameter 59mm, thickness 10mm
Then, an opaque quartz partition plate 6 having a through hole with an inner diameter of 12.5 mm is fitted into the introduction pipe 5, and in that state an outer diameter of 56 mm,
The boat 1 is put into an opaque quartz heat shield tube 7 having an inner diameter of 54 mm and a length of 800 mm. Next, outer diameter 66 mm, inner diameter 6
After putting about 1 kg of the P9 ingot, which is a group V element raw material, into the transparent quartz sealed tube 8 having a length of 0 mm, a length of 12 mm, and a shaft connecting ring on one side of the sealed portion, the introduction tube 5,
The boat 1 to which the partition plate 6 is attached is put together with the heat shield tube 7. After that, the mouth of the quartz sealed tube 8 is closed, and the inside is filled with 10 ⁻⁶ To.
Vacuum up to rr order and cut off. Then, the quartz sealed tube 8 is pushed into the furnace using the high-pressure vessel 10 while being connected to the sealed tube moving shaft 11, and the cap 4 is placed in the high-frequency coil 12 so that the cap 4 does not generate excessive heat at the start of heating. It is installed at a position of 20 mm to 30 mm protruding from one end to the outside. Then, while heating, nitrogen gas is put into the high-pressure container 10 and pressurized to 40 kg / cm ² . As for the heating temperature, a part of the boat 1 is kept near 1470 ° C. which is the melting point of GaP by the high frequency coil 12, P9 is raised from 300 ° C. to 700 ° C. by the resistance heater 13, and Ga2 in the boat 1 is raised by the resistance heater 14. Fifty
Hold in the range of 0 ° C to 600 ° C. As a result, P9 sublimates and becomes vapor, which passes through the introduction pipe 5 and reacts with Ga2 in the boat 1 heated to a temperature near 1470 ° C.
It becomes an aP melt. And 40 mm after 2 hours from the start of heating
The quartz sealed tube 8 is moved by the sealed tube moving shaft 11 at a speed of / Hr to gradually solidify GaP from the end, and a GaP polycrystalline ingot having a length of about 700 mm and a weight of about 2.9 kg is taken in about 19 hours. obtain. At this time, the temperature near the inlet of the introduction pipe 5 and the partition plate 6 is much lower than 1050 ° C.
Since the temperature is controlled from 00 ° C to 700 ° C, the reaction between the vapor of P9 and the inner surfaces of the partition plate 6 and the quartz sealed tube 8 is unlikely to occur, and the narrow gap between the partition plate 6 and the quartz sealed tube 8 causes P9
The steam of the invades the part where the boat 1 is placed, and part 147
Even if SiO reacts with the surface of the heat shield tube 7 heated to a temperature of about 0 ° C., the boat 1 is sealed, so that it does not come into contact with the GaP melt inside and the partition plate 6 is sandwiched. While the internal pressure on the P9 side is slightly higher than the internal pressure on the boat 1 side while the temperature is being raised from 300 ° C to 700 ° C, SiO enters the P9 side and enters the boat 1 from the inlet of the introduction pipe. Since it is unlikely to enter, it is possible to suppress Si mixed in GaP during the synthesis to be small.

[0008]

According to the present invention, SiO generated by the reaction between the group V element and quartz is suppressed, and the SiO-III-
Since the possibility of contact with the group V compound semiconductor melt can be reduced, the Si concentration in the group III-V compound semiconductor can be reduced without lowering the synthesis temperature, and in the case of GaP synthesized by the conventional method, The Si concentration was 1.3 ppm or more, whereas it was 0.3 ppm or less in the examples.

[Brief description of drawings]

FIG. 1 is a schematic diagram of GaP synthesis by a horizontal zone melting method using high frequency induction heating and a heating temperature distribution diagram in a furnace showing an embodiment of the present invention.

[Explanation of symbols]

 1 boat 2 group III element raw material 3,4 cap 5 introduction tube 6 partition plate 7 heat shield tube 8 quartz sealed tube 9 V group element raw material 10 high pressure vessel 11 shaft for moving sealed tube 12 high frequency coil 13,14 resistance heater

Claims (1)

[Claims] 1. A closed boat in which a group III element raw material is filled in a quartz sealed tube and a group V element raw material are separately arranged, and the space between the boat and the group V element raw material is slightly smaller than the inner diameter of the quartz sealed tube. A small partition plate is placed, and an introduction pipe for introducing the vapor of the group V element is installed so as to extend from one end of the boat and penetrate the partition plate, and the partition plate, the inlet of the introduction pipe, and the group V element raw material are A method for producing a III-V group compound semiconductor, characterized in that the temperature of the placed range is less than 1050 ° C.