JP2001335307A - Method for synthesis of polycrystal of compound semi- conductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for synthesis of polycrystal of a group III-V compound semi-conductor in which uniformity of thickness and increase of charging amount of raw materials are contrived. SOLUTION: This method for synthesis of a polycrystal of compound semiconductor comprises arranging a boat 10 filled with a group III raw material 40 at one end inside a seal pipe 6, and a group V raw material 90 at the other end, heating the whole seal pipe, reacting the group III raw material with the material gas generated from the group V raw material by locally heating the group III material at a higher temperature, and synthesizing a group III-V compound semiconductor polycrsytal while relatively shifting a high temperature part. In this case, the inside of the boat is compared into the regions 31, 32 and 33 in its longitudinal direction by arranging, along the width direction of the boat, the partition materials 21 and 22 which are formed of the group III-V compound semiconductor polycrystal, and the group III material is divided into three and filled in the comparted regions, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for preparing III-
The present invention relates to a method for synthesizing a group V compound semiconductor polycrystal, and in particular, it is possible to achieve a uniform thickness of the obtained group III-V compound semiconductor polycrystal and an increase in raw material input amount.
The present invention relates to a method for synthesizing a group V compound semiconductor polycrystal.

[0002]

2. Description of the Related Art Group III-V compound semiconductors such as GaP are
Conventionally, it is used for materials such as opto devices such as laser diodes and light emitting diodes, and high-speed devices such as HEMTs.

[0003] In such a III-V compound semiconductor, it is difficult to directly react a group III material such as Ga with a group V material such as P to grow a single crystal.
First, a group III compound semiconductor polycrystal was synthesized, and then this III-
III using Group V compound semiconductor polycrystal by LEC method etc.
A method of growing a group V compound semiconductor single crystal has been employed.

The III-V compound semiconductor polycrystal is loaded into a horizontal high-pressure furnace b as shown in FIG. 5 by placing a sealed tube a made of quartz or the like filled with each raw material as shown in FIG. And a method of synthesizing.

That is, as shown in FIG.
The group raw material c is filled in a boat boat or a cylindrical boat boat e (see FIG. 6) provided with a slit d, and the entire boat e is housed in an inner tube f made of quartz or the like and sealed. A group V raw material g such as P is disposed at one end of the tube a, and is disposed at the other end of the sealed tube a via a heat shielding plate h. The sealed tube a filled with the raw material and the like is then vacuum-sealed and sealed.

Next, the above-mentioned sealed tube a which has been sealed by vacuum
Is carried into a horizontal high-pressure furnace b composed of a high-pressure vessel having a high-frequency coil i at the center and a resistance heater j on both sides of the high-frequency coil i at the center.

Then, the entire sealed tube a is heated in the horizontal high-pressure furnace b, and the high-frequency coil i
While the group III raw material c is locally further heated to a high temperature,
The raw material gas generated from the group V raw material g is introduced into the inner tube f via the introducing tube k attached to the heat shield h, and
By reacting with the group I raw material c and moving the sealed tube a in the horizontal high-pressure furnace b in the direction of the arrow α or fixing the sealed tube a and moving the horizontal high-pressure furnace b in the opposite direction ( That is, a III-V group compound semiconductor polycrystal (relatively moving the high temperature portion) is synthesized.

[0008]

The above-mentioned sealed tube a
In the method of synthesizing a III-V compound semiconductor polycrystal to which the horizontal high-pressure furnace b is applied, there is a problem that the thickness of the obtained III-V compound semiconductor polycrystal tends to be non-uniform. In particular, the reaction start end portion tends to be thin, and the reaction end portion tends to be thick. In extreme cases, the difference in wall thickness between both end portions may be 15 mm or more.

Further, when the difference in wall thickness is large, the raw material may spill from the graphite boat e at the end of the reaction, which causes problems such as deterioration of the quality and damage to the quartz inner tube f and the graphite boat e. There was a problem. In particular, there is a problem that when the quartz outer tube (that is, the sealed tube a) is affected, the sealed tube is ruptured, so that economic damage is further increased.

[0010] Further, if the temperature of the group V raw material g is increased to increase the supply amount in order to increase the wall thickness of the reaction start end, the raw material vapor pressure increases, and the pressure difference between the inside and outside of the sealed tube a increases. And the temperature control becomes difficult.

[0011] For this reason, the volume of the synthesized III-V compound semiconductor polycrystal is limited by the amount of the raw material charged to the graphite boat e.
Therefore, there was a problem that the capacity of the graphite boat e could not be fully utilized.

The present invention has been made in view of such a problem.
It is an object of the present invention to provide a method for synthesizing a group III-V compound semiconductor polycrystal, which can make the thickness of the group III compound semiconductor polycrystal uniform and increase the amount of raw material input.

[0013]

That is, according to the first aspect of the present invention, a boat filled with a Group III raw material is disposed at one end in a sealed tube, and a Group V raw material is placed at the other end in the sealed tube. Arrange, heat the entire sealed tube and locally heat the Group III raw material in the boat to a higher temperature to react the raw material gas generated from the Group V raw material with the Group III raw material, Assuming a method of synthesizing a compound semiconductor polycrystal in which a group III-V compound semiconductor polycrystal is synthesized while gradually moving relative to each other, one or more partition members made of the group III-V compound semiconductor polycrystal are placed in the width direction of the boat. Along with dividing the inside of the boat into two or more regions along its length, the group III raw material is distributed and filled in each of the divided regions. Is what you do.

According to the method for synthesizing a compound semiconductor polycrystal according to the first aspect of the present invention, one or more partition members made of a group III-V compound semiconductor polycrystal are arranged along the width direction of the boat. The interior of the boat is divided into two or more regions along the length thereof, and the group III raw materials are distributed and filled in each of the divided regions. In each of the regions, the group III-V compound semiconductor polycrystals are individually synthesized, and the whole is integrated via the above-mentioned partition member made of the group III-V compound semiconductor polycrystal.

[0015] By the action of the partition member made of polycrystalline III-V compound semiconductor, the boat was filled in the boat regardless of the degree of growth of the crystal at the beginning of the reaction.
Since the phenomenon that the group III raw material is pushed to the terminal end side (that is, the bias phenomenon of the raw material) is eliminated, the thickness of the obtained III-V compound semiconductor polycrystal can be made uniform and the raw material can be pushed. As a result, it is possible to prevent the raw material from spilling from the boat, and to increase the raw material input amount.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

That is, the method of synthesizing a compound semiconductor polycrystal according to the present embodiment comprises, as shown in FIG. 1, two boats formed of a group III-V compound semiconductor polycrystal in a boat filled with a group III raw material. Conventionally, except that the partitioning material is arranged and the inside of the boat is divided into three regions along its length direction, and that the group III raw material is distributed and filled in each of the divided regions. Is almost the same as the synthesis method.

First, as shown in FIG. 2, the boat 10 has a cylindrical boat main body 12 made of graphite having a slit 11 formed in the upper outer peripheral surface, and a graphite boat closing both open portions of the cylindrical boat main body 12. The boat 10 has two substantially semi-cylindrical partition members 21 made of III-V compound semiconductor polycrystals.
22 are arranged along the width direction of the boat 10 with the arc side thereof facing downward, and the partitioning materials 21 and 22 divide the inside of the boat 10 into three regions 3 along its length direction.
1, 32, and 33, and each area 31,
Group III raw materials 40 are distributed and filled in 32 and 33, respectively. It is desirable that the volumes of the three regions 31, 32, and 33 and the amounts of the group III raw materials 40 charged in the respective regions be equal to each other in principle, but they are not necessarily required to be equally divided into three. In this example, two partition members 2
1 and 22 are arranged, but any number of 1 and 22 is optional.

The boat 10 containing the partition members 21 and 22 and the group III raw material 40 is housed in a quartz inner tube 5, and as shown in FIG. 6), a group V raw material 90 is disposed at the other end of the quartz sealed tube 6, and a heat shield plate 71 made of opaque quartz is provided at substantially the center of the quartz sealed tube 6. , 72 are arranged. The heat shield plates 71 and 72 are provided with an introduction pipe 80.
The space in which the group V raw material 90 is arranged and the inner quartz tube 5 communicate with each other via the introduction tube 80.

Next, the mouth of the quartz sealed tube (outer tube) 6 containing the inner quartz tube 5, the heat shielding plates 71 and 72, and the group V raw material 90 and the like is closed, evacuated, and then sealed off. .

Next, a high-frequency coil 51 is provided at the center, and the high-frequency coil 51 is provided at the center thereof. The quartz sealed tube (outer tube) 6 is carried in, and an inert gas such as nitrogen is filled in a high-pressure vessel 54 of a horizontal high-pressure furnace 50 to set the high-pressure furnace to a high-pressure state. The quartz sealed tube (outer tube) 6
The whole is heated, and the high-frequency coil 51 is operated to locally heat the group III raw material 40 in the region 33 of the boat 10 to a higher temperature.

The raw material gas from the group V raw material 90 introduced into the quartz inner tube 5 through the introducing tube 80 attached to the heat shielding plates 71 and 72 and the group III raw material 40 in the region 33 of the boat 10 And move the quartz sealed tube (outer tube) 6 or the horizontal high-pressure furnace 50 (ie,
(The high-temperature portion is relatively moved), and the above reactions are sequentially advanced from the region 33 to the region 31 in the boat 10 to be integrated.
A III-V compound semiconductor polycrystal is synthesized.

According to the synthesizing method according to this embodiment,
Due to the action of the partition members 21 and 22 made of the polycrystalline group III-V compound semiconductor, the group III raw material 40 filled in the boat 10 is filled regardless of the degree of growth of the reaction start part crystal in the region 33. Since the phenomenon of being pushed to the reaction termination portion side is eliminated, the thickness of the obtained III-V compound semiconductor polycrystal can be made uniform, and the boat 10 caused by the pushing of the group III raw material 40 can be removed from the boat 10. This has the advantage that the raw material spill can be prevented, and the amount of raw material input can be increased.

The shape of the partition members 21 and 22 made of a polycrystalline group III-V compound semiconductor is appropriately set according to the internal shape of the boat 10 on which the partition members are arranged. Is cylindrical, it is set to a substantially semi-cylindrical shape having an inside diameter substantially the same as the inside diameter of the boat. The height may be at least half the inner diameter of the boat, and the composition of the III-V compound semiconductor polycrystal is arbitrary.

[0025]

Embodiments of the present invention will be specifically described below.

Embodiment 1 First, an outer diameter of 48 m shown in FIG.
m, 40 mm in diameter and 15 m in width along the width direction in a cylindrical graphite boat 10 having an inner diameter of 40 mm and a length of 745 mm.
m, partition members 21 and 22 made of GaP polycrystal having a height of 30 mm are arranged, and the inside of the boat 10 is divided into three equal parts along its length direction, and each divided into three equal parts Gallium (Ga), which is a Group III raw material 40, was divided into three equal portions and filled in 31, 32, and 33, respectively.

Next, the boat 10 containing the partition members 21 and 22 and the group III raw material 40 is housed in the inner quartz tube 5 and, as shown in FIG. And 920 g of red phosphorus (P), which is a group V raw material 90, was placed at the other end of the quartz sealed tube 6. Note that, in the quartz sealed tube 6, opaque quartz heat shielding plates 71 and 72 to which an introduction tube 80 for introducing the raw material gas of the group V raw material 90 into the inner quartz tube 5 are arranged. .

Next, the opening of the quartz inner tube 5, the heat shielding plates 71 and 72, the quartz sealed tube 6 containing the group V raw material 90 and the like is closed, and the inside is evacuated to the order of 10 ^-6 Torr. Cut off the seal.

Next, the high-frequency coil 51 is provided at the center, and the high-frequency coil 51 is provided at the center thereof. The above quartz sealed tube 6 is carried in,
After filling the high-pressure vessel 54 of the horizontal high-pressure furnace 50 with nitrogen gas and setting the high-pressure furnace to a high-pressure state (40 kg / cm ² ), resistance heaters 52 and 53 are operated to heat the entire quartz sealed tube 6. Red phosphorus (P), which is a group V raw material 90, is heated to 300 ° C. to 7
The temperature is raised to 00 ° C., and the group III raw material 40 in the boat 10
Gallium (Ga) is held in the range of 500 ° C. to 600 ° C., and the region 33 of the boat 10 is held at a temperature around 1470 ° C., which is the melting point of GaP, by operating the high-frequency coil 51.

The raw material gas from the group V raw material 90 introduced into the quartz inner tube 5 through the introducing tube 80 attached to the heat shielding plates 71 and 72 and the group III raw material 40 in the region 33 of the boat 10 And the quartz sealed tube 6 is moved in the horizontal high-pressure furnace 50 in the direction of the arrow α (that is, the high-temperature portion is relatively moved), and the region 33 in the boat 10 is moved.
From above to the region 31 to synthesize an integrated group III-V compound semiconductor (GaP) polycrystal.

The partition members 21 and 22 function as partition members until they are heated in the high-temperature portion, and after being heated in the high-temperature portion, melted and synthesized in each region. It is integrated with a semiconductor (GaP) polycrystal.

Then, the thickness of the crystal is determined from the obtained III-V compound semiconductor (GaP) polycrystal, the spillage of the raw material from the boat 10 during the synthesis is examined, and the utilization rate (%) of the graphite boat is measured. I also checked. The results are shown in Table 1 below.

Example 2 The fact that 2100 g of gallium (Ga), which is a group III raw material 40, was divided into three equal portions and charged into the respective regions 31, 32, and 33 of the boat 10, A III-V compound semiconductor (GaP) polycrystal was synthesized under substantially the same conditions as in Example 1 except that the input amount of a certain red phosphorus (P) was changed to 960 g.

Then, the crystal thickness is determined from the obtained III-V compound semiconductor (GaP) polycrystal, the spillage of the raw material from the boat 10 during the synthesis is investigated, and the utilization rate (%) of the graphite boat is determined. I also checked. The results are also shown in Table 1 below.

Example 3 Group 250 raw material gallium (Ga) (2250 g) was divided into three equal parts and charged into each of the regions 31, 32, and 33 of the boat 10; A group III-V compound semiconductor (GaP) polycrystal was synthesized under substantially the same conditions as in Example 1 except that the input amount of a certain red phosphorus (P) was changed to 1050 g.

Then, the crystal thickness is determined from the obtained III-V compound semiconductor (GaP) polycrystal, the spillage of the raw material from the boat 10 during the synthesis is examined, and the utilization rate of the graphite boat (%) I also checked. The results are also shown in Table 1 below.

Comparative Example A III-V compound semiconductor (GaP) polycrystal was synthesized under substantially the same conditions as in Example 1 except that the partition members 21 and 22 made of GaP polycrystal were not applied. .

Then, the crystal thickness is determined from the obtained III-V compound semiconductor (GaP) polycrystal, the spillage of the raw material from the boat 10 during the synthesis is examined, and the utilization rate of the graphite boat (%) I also checked. The results are also shown in Table 1 below.

[0039]

[Table 1] In Table 1, "thickness difference" is obtained by subtracting the minimum thickness value from the maximum thickness value of the synthesized III-V compound semiconductor (GaP) polycrystal.

The “raw material spill rate” is the ratio of the number of spilled raw materials to the number of composites.

The "graphite boat utilization rate (%)" is the ratio of the synthesized III-V compound semiconductor (GaP) polycrystal to the internal volume of the graphite boat.

[Confirmation] From the results in Table 1, the following can be confirmed. (1) In each example, the difference between the maximum thickness value and the minimum thickness value of the synthesized III-V compound semiconductor (GaP) polycrystal (that is, the “thickness difference”) is about 5 mm. The difference in wall thickness is dramatically reduced as compared with the example of 13.9 mm. (2) In addition, since the maximum thickness of the synthesized III-V compound semiconductor (GaP) polycrystal is smaller than that of the comparative example, raw material spillage is prevented. (3) The utilization rate (%) of the graphite boat in Example 3 was 8
It is 4.5%, and the utilization rate is 10 compared with the comparative example.
It can be confirmed that the raw material input amount can be increased by 13%.

[0043]

According to the method for synthesizing a compound semiconductor polycrystal according to the first aspect of the present invention, at least one partition member made of a group III-V compound semiconductor polycrystal is arranged along the width direction of the boat. And divide the inside of the boat into two or more areas along the length of the boat.
Since the group III raw materials are distributed and filled respectively, in each region partitioned by the partition material,
-Group V compound semiconductor polycrystals are synthesized individually and II
The whole is integrated via the above-mentioned partition member made of polycrystalline group IV-compound semiconductor.

Then, by the action of the above-mentioned partition member made of the polycrystalline group III-V compound semiconductor, the boat was filled into the boat regardless of the degree of growth of the crystal at the beginning of the reaction.
Since the phenomenon that the group III raw material is pushed to the terminal end side (that is, the bias phenomenon of the raw material) is eliminated, the thickness of the obtained III-V compound semiconductor polycrystal can be made uniform and the raw material can be pushed. Therefore, there is an effect that it is possible to prevent the raw material from spilling from the boat due to the above, and it is possible to increase the raw material input amount.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration in a quartz sealed tube applied to a method for synthesizing a compound semiconductor polycrystal according to an embodiment of the present invention, and a positional relationship between a group III material and a group V material arranged in the sealed tube. .

FIG. 2 is a schematic perspective view showing a boat applied to a method for synthesizing a compound semiconductor polycrystal according to an embodiment of the present invention and a partition member disposed therein.

FIG. 3 is an explanatory view showing a method for synthesizing a compound semiconductor polycrystal according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a configuration inside a quartz sealed tube applied to a method of synthesizing a compound semiconductor polycrystal according to a conventional example, and a positional relationship between a group III raw material and a group V raw material arranged in the sealed tube.

FIG. 5 is an explanatory view showing a method for synthesizing a compound semiconductor polycrystal according to a conventional example.

FIG. 6 is a schematic perspective view of a boat applied to a compound semiconductor polycrystal synthesis method according to a conventional example.

[Explanation of symbols]

 Reference Signs List 5 inner quartz tube 6 sealed quartz tube 10 boat 21 partitioning material 22 partitioning material 31 region 32 region 33 region 40 Group III raw material 90 Group V raw material

Claims (1)

[Claims] 1. A boat filled with a group III raw material is disposed at one end of a sealed tube, and a group V raw material is disposed at the other end of the sealed tube. III
The group III source is locally heated to a higher temperature to cause the source gas generated from the group V source to react with the group III source, and the III-V compound semiconductor polycrystal is formed while gradually moving the high temperature part relatively. In the method for synthesizing a compound semiconductor polycrystal to be synthesized, one or more partition members composed of a group III-V compound semiconductor polycrystal are arranged along the width direction of the boat and the inside of the boat extends along the length direction. A method for synthesizing a compound semiconductor polycrystal, wherein the compound is divided into the above regions, and the group III raw material is distributed and filled in each of the divided regions.