JPH0491442A - Manufacturing apparatus for crystal - Google Patents

Abstract

PURPOSE:To obtain an apparatus for obtaining an epitaxial crystal containing a predetermined composition and made of HgCdTe, etc., having high uniformity of composition with high reproducibility by providing a vertical reaction tube, a substrate mounting base, a rotary shaft, a carrier gas inlet tube, an organic metal gas inlet tube, and heating means. CONSTITUTION:A vertical reaction tube 11 provided with a liquid reservoir 12 for containing material liquid for epitaxial growth in a bottom, a substrate mounting base 13 capable of mounting a substrate 18 oppositely to the surface of the liquid and rotating, a rotary shaft 16 connected to the base 13 to transmit the rotation of rotary means 20, a carrier gas inlet tube 23 inserted into the tube 11 for introducing carrier gas for evaporating the liquid, an organic metal gas inlet tube 21 inserted into the tube 11 between the base 13 and the reservoir 12 for introducing organic metal gas, and heating means 14 for heating the tube 11 and the reservoir 12 are provided. Further, for example, an organic metal gas reverse flow preventing partition 22 having a plurality of through holes 19 for reducing the internal sectional area of the tube 11 is provided between the reservoir 12 and the tube 21.

Description

[Detailed Description of the Invention] [Table of Contents] Overview ・・・ ・・・ ・・・・・・・・・ ・・
・Page 5 Industrial application fields・・・・・・・・・・・・
・・・・・・・・・・・・Page 6 Conventional technology...
・・・・・・・・・・・・Page 6 Problem to be solved by the invention・・・・・・・・・Page 8 Means to solve the problem・・・・・・・・・・・・・・10 page action ・・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・Page 13 Example・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・Page 18 Effects of the invention・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・Page 27 It is configured by providing an introduction tube and a heating means installed on the side surface of the reaction tube to heat the substrate and the liquid reservoir.

〔overview〕

Regarding the manufacturing equipment for compound semiconductor crystals, the aim is to provide a crystal manufacturing equipment that can obtain epitaxial crystals having a predetermined composition and high compositional uniformity with good reproducibility. a vertical reaction tube provided therein; a rotatable substrate installation stand on which a substrate can be placed facing the liquid surface of the raw material liquid; and a rotation shaft connected to the substrate installation stand and transmitting the rotation of the rotation means. a carrier gas introduction tube inserted into the reaction tube to introduce a carrier gas that evaporates the raw material liquid; and a carrier gas introduction tube inserted into the reaction tube between the substrate installation stand and the liquid reservoir to introduce an organometallic gas. Organometallic Gas [Industrial Application Field] The present invention relates to the MOCVD growth method of narrow bandgap compound semiconductors containing mercury (Hg) such as mercury-cadmium-tellurium (HgCdTe) used as materials for infrared sensors. The present invention relates to a crystal manufacturing apparatus for obtaining an epitaxial crystal having a high composition and high composition uniformity with good reproducibility.

(Prior art) Conventional MOCV for manufacturing crystals such as HgCdTe
A crystal manufacturing apparatus according to method D is shown in FIG. 8. As shown in FIG. mercury is introduced into a reaction tube 3, and is supplied to a substrate 4 for epitaxial growth housed in the reaction tube.

Although not shown, cadmium (Cd) and tellurium (Te)
) The hydrogen gas described above is introduced into an evaporator containing a liquid organometallic compound, and the hydrogen gas capable of supporting the organometallic compound is supplied into the reaction tube 3 from an organometallic gas introduction pipe 5.

And a carbon board installation stand 6 on which this board 4 is installed.
By heating the substrate 4 by heating means 7 consisting of a high-frequency induction coil provided outside the reaction tube, mercury and the organometallic compound are thermally decomposed, and a compound semiconductor crystal containing mercury is placed on the substrate in a vapor phase. Growing.

As another method using a horizontal reaction tube, as shown in FIG. 9, a mercury reservoir 8 is installed upstream of the substrate 4 for epitaxial growth when viewed from the gas flow direction shown by arrow A in the reaction tube 3. Then, the mercury in the mercury reservoir 8 is heated by a heater 9 provided outside the reaction tube 3, and the mercury is supplied to the substrate 4.
Hydrogen gas that can support organometallic compounds such as diethyl tellurium and dimethyl cadmium is introduced from the gas introduction pipe 2 to produce Hg.
A method is known in which a CdTe epitaxial crystal is grown on the substrate 4 in a vapor phase.

[Problem to be solved by the invention]

Among the conventional methods, the former method shown in FIG. 8 uses organic cadmium (Cd) such as dimethyl cadmium,
A raw material gas such as organic tellurium (Te) such as diethyl tellurium is diluted with hydrogen gas or the like and introduced into the reaction tube 3 without passing through the mercury evaporator 1. Therefore, there is a problem that the mercury does not mix uniformly with the gas introduced through the evaporator 1, and the partial pressure of mercury in the reaction tube 3 becomes non-uniform.

Furthermore, the area between the mercury evaporator 1 and the substrate 4 for epitaxial growth is heated by a heater 9, but if there is a low temperature area in between, mercury condensation, etc. will occur, and the amount of mercury supplied to the reaction tube 3 will decrease. There is also the problem of instability.

In addition, in the latter method shown in FIG. There is a problem that the mercury concentration is not stable.

Furthermore, since hydrogen gas containing organic metals such as dimethyl cadmium passes over the mercury reservoir 8 through the gas introduction pipe 2, the mercury surface of the mercury reservoir is contaminated, and the amount of mercury evaporated from the mercury reservoir 8 is unstable. There's a problem.

Furthermore, both methods have the problem that, since mercury vapor is heavy, this mercury vapor is unevenly distributed below the reaction tube 3, and the mercury partial pressure around the substrate 4 becomes non-uniform.

In addition, on the gas discharge side, in order to take in and take out the substrate 4,
A flange 10 with a large diameter is required, and this flange is equipped with O, which has poor heat resistance, in order to improve airtightness inside the reaction tube.
Since it is necessary to use a ring or the like, there is a problem in that the temperature in that part becomes low and the mercury partial pressure in the reaction tube becomes non-uniform.

In addition, since the mercury vapor pressure is high and the mercury partial pressure is high, the amount of mercury consumed from the mercury reservoir 8 is large, and the amount of mercury in the mercury reservoir changes during growth, so the amount of mercury supplied to the substrate 4 is unstable. There is a problem.

There is also the problem that with regard to organometallic compounds other than mercury, there is no guarantee that they will be uniformly supplied near the substrate, and once the crystal manufacturing equipment is decided, it is not possible to adjust the organometallic concentration near the substrate by changing the crystal growth conditions. There is.

As mentioned above, in conventional crystal manufacturing equipment, when manufacturing a crystal containing mercury, which easily evaporates, it is difficult to maintain a constant mercury partial pressure around the substrate with high precision, which reduces the rate of mercury adhesion to the substrate. Since the mercury dissociation rate from the substrate is not constant and the organic metal concentration near the substrate cannot be adjusted, there are problems in that the control accuracy of the crystal composition is poor and the uniformity of the composition within the crystal is also poor.

[Means to solve the problem]

The crystal manufacturing apparatus of the present invention includes a vertical reaction tube equipped with a liquid reservoir at the bottom for containing a raw material liquid for epitaxial growth, and a substrate that can be installed facing the surface of the raw material liquid and can be rotated. a support rod connected to the substrate installation table and transmitting rotation of the rotation means; inserted into the reaction tube;
a carrier gas introduction tube for introducing a carrier gas for evaporating the raw material liquid = 10; an organometallic gas introduction tube inserted into a reaction tube between the substrate installation stand and the liquid reservoir and introducing an organometallic gas; The method is characterized in that a heating means is installed on a side surface of the reaction tube and heats the substrate and the liquid reservoir.

Further, the upper part of the substrate of the reaction tube is inscribed in the inner wall of the reaction tube at a predetermined interval so as to be freely inserted, and has a through hole in the center for inserting a rotation shaft for rotating the substrate installation stand; 1; A spacer for preventing heat dissipation is provided which is heated by the heating means on the side surface of the reaction tube.

Further, a columnar organometallic gas backflow prevention partition wall having a plurality of through holes for reducing the internal cross-sectional area of the reaction tube is provided between the liquid reservoir and the organometallic gas introduction tube.

Further, the tip of the carrier gas introduction pipe is equipped with a nozzle that sprays the carrier gas onto the surface of the raw material liquid in the liquid reservoir, or is immersed in the raw material liquid in the liquid reservoir, and the tip of the carrier gas introduction pipe is Each is provided with a gas flow rate adjusting means.

Further, the structure of the nozzle for spraying the carrier gas onto the surface of the raw material liquid in the liquid reservoir is such that it has an open end portion provided with a plurality of carrier gas blowing holes like the tip structure of a water blower.

Further, a plurality of gas outlet ports at the tip of the organometallic gas introducing tube are provided with flow rate adjusting means so that the gas is blown toward the growth surface of the substrate, The gas blow-off ports are arranged at positions that are rotationally symmetrical about the rotation axis of the substrate mounting table.

Furthermore, a raw material liquid supply tank connected to the liquid reservoir by a communication pipe is provided outside the reaction tube, and a light source that obliquely impinges a light beam on the raw material liquid surface of the raw material liquid supply tank, and a source liquid of the light beam. It is equipped with a raw material liquid level needle consisting of a photodetector that detects reflected light on the liquid surface.

Further, the communication pipe is formed of a deformable flexible pipe, and the raw material liquid supply tank can be moved up and down by a moving mechanism in response to a signal from a liquid level meter of the raw material liquid.

Furthermore, a raw material liquid replenishment device is connected to the raw material liquid supply tank, and the raw material liquid is sent to the raw material liquid supply tank according to the signal from the raw material liquid level level needle, and the raw material liquid in the raw material liquid supply tank is Try to keep the liquid level constant.

[For production]

In the crystal manufacturing apparatus of the present invention, a reservoir 12 of a raw material liquid such as mercury is arranged at the bottom of a vertical reaction tube 11 shown in FIG. 1, and a heater 14 is installed to heat the reaction tube and the reservoir. We are prepared.

Since the mercury evaporated from the mercury in the liquid reservoir 12 is heavy, the mercury concentration tends to increase the lower it goes. Therefore, the liquid reservoir is placed under the substrate installation stand 13 and mercury is supplied from there. This stabilizes the mercury concentration distribution and improves the control accuracy of the mercury partial pressure near the substrate 18 for epitaxial growth.

Further, the substrate mounting table 13, which can hold the substrate 18 downward with the growth surface facing the liquid reservoir 12, has a structure in which mercury is supplied from below, and the mercury concentration in the reaction tube 11 is determined by the height. Combined with this, the concentration of mercury on the substrate surface can be kept constant.

Further, the rotation mechanism of the substrate mounting table 13 is effective for making the mercury concentration on the surface of the growth substrate more uniform.

Further, on the gas discharge side, a spacer 17 inscribed in the inner wall of the reaction tube so as to have a narrow gap with the reaction tube 11 is provided on the substrate side of the flange 15 having a large diameter for taking the substrate 18 in and out, and this spacer is heated. It is equipped with a heater 14^. By setting the spacer 17 to the reaction tube 11 at a distance of about 10 m or less, backflow of gas is reduced, and even if the flange 15 is at a low temperature, it produces the same effect as if the entire inside of the reaction tube 11 were raised to a high temperature.

This spacer 17 has a simple columnar or cylindrical structure, and is formed using a highly heat-resistant material such as quartz glass.

Furthermore, the outlet at the tip of the organometallic gas introduction tube 21 that supplies crystalline components other than mercury to the reaction tube is provided between the liquid reservoir 12 and the substrate installation stand 13, so that the mercury in the liquid reservoir 12 can be It is possible to reduce contamination caused by metals.

Furthermore, it is possible to provide an area between the mercury reservoir 12 and the outlet at the tip of the organometallic gas introduction tube 21 to reduce the cross-sectional area of the reaction tube 11, for example by reducing the radius of the reaction tube 11. It is effective in preventing backflow of metal gas. An effective way to reduce this cross-sectional area is to install a cylinder with multiple holes or a cylindrical organometallic gas backflow prevention partition wall 22, thereby uniformly supplying mercury to the growth substrate. It can also be done.

Further, by attaching the backflow prevention partition 22, it is possible to prevent the organometallic gas from flowing back into the mercury reservoir 12, thereby preventing the liquid surface of the mercury reservoir from being contaminated and changing the amount of mercury evaporation.

A flow rate adjustment means 26 is installed in each of the plurality of organometallic gas introduction tubes 21, with the outlet at the tip of the organometallic gas introduction tube directed in the direction in which the gas is blown onto the growth surface of the growth substrate.
By attaching this, the distribution of the amount of organic metal supplied to the substrate can be adjusted. The synergistic effect with the rotation mechanism of the substrate mounting table 13 makes it possible to uniformly supply the organic metal to the surface of the substrate.

In particular, different metal-organic gas inlet pipes are provided for different types of organic metals, and gas outlets for the different types of organic metals are arranged at positions rotationally symmetrical about the rotation axis 16 of the substrate installation table 13. As a result, the distribution of the amount of organic metal supplied to the substrate surface can be adjusted independently for each organic metal component.

In addition, the blowing nozzle at the tip of the hydrogen carrier gas introducing pipe 23 for evaporating the mercury in the raw material liquid is connected to the liquid reservoir 12.
In order to reliably supply mercury from the mercury into the reaction tube 11, a structure may be adopted in which the mercury is immersed below the liquid surface of the liquid reservoir 12 and hydrogen is bubbled therein.

In addition, in order to stably supply mercury to the reaction tube, the gas blowing nozzle of the hydrogen carrier gas introduction tube is
It is also effective to spray hydrogen onto the mercury surface as shown in Figure (a). In order to supply mercury more stably, it is preferable that the hydrogen blowing nozzle has an open end 25 like the tip of a watering can, as shown in FIG. 4(c). Further, by providing a plurality of hydrogen carrier gas introduction tubes and providing a flow rate adjustment means for each carrier gas introduction tube, mercury can be uniformly supplied to the reaction tube by adjusting the flow rate.

Furthermore, as shown in FIG.
By providing a mercury supply tank 28 connected to the reaction tube 1
By supplying mercury to the mercury reservoir 12 from the outside of the mercury reservoir 12, the mercury liquid level in the reservoir can be kept constant.

This mercury supply tank 28 stores relatively low-temperature mercury, and from the viewpoint of strength, it is preferable to have a structure in which the inside of the metal is coated with chemically stable fluorinated ethylene. In order to keep the mercury liquid level in this mercury supply tank constant, a mercury liquid level meter is necessary, and various types of liquid level meters can be considered, but as shown in Fig. 6, the light source 31 and Photodetector 33
A mercury level needle with a combination of these is preferable because the mercury level can be measured without contact. In addition, a mercury replenishment device 34 was provided to maintain a constant level of the mercury liquid level in the mercury supply tank 28 shown in FIG. A structure is adopted in which a predetermined amount of mercury is replenished into the mercury supply tank according to the liquid level of mercury.

In addition to using a mercury replenishment device, another method is to prevent mercury contamination by constructing the communication pipe 27 with a deformable pipe and changing the height of the mercury supply tank with a moving mechanism that moves it up and down. Preferable for its meaning.

For the same reason as the mercury supply tank, this deformable communication tube can be made of fluoroethylene or a tube made of fluoroethylene inside a metal bellows.

A mercury supply tank 28 connected to the bottom of the mercury reservoir 12 through a communication pipe 27 supplies mercury from the outside of the reaction tube 11 to the reservoir 12 to keep the mercury liquid level in the reservoir constant. . By keeping the height of the liquid level in the liquid reservoir constant, the amount of mercury evaporated from the liquid reservoir 12 to the reaction tube 11 is made more stable over time.

〔Example〕

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

FIG. 1 is a block diagram of an embodiment of the crystal manufacturing apparatus of the present invention, and shows an MOCVD crystal manufacturing apparatus. The present embodiment will be described with reference to FIG. 1. A liquid reservoir 12 containing mercury is placed at the bottom of a vertical reaction tube 11 made of quartz glass or the like. 20 From the liquid reservoir 12 to the substrate installation stand 13
The walls of the reaction tube 11 up to the temperature of the mercury reservoir 12 or higher (
For example, it can be heated to 250° C. by a heater 14 or the like. The substrate mounting table 13 is made of carbon or the like, and can be heated to, for example, 4 (10)° C. using a high frequency induction heating method.

The substrate installation table 13 uses a vacuum chuck or the like to place the substrate 18 facing downward so as to face the liquid reservoir 12.

The flange 15 on the gas discharge side is made of stainless steel or the like, and is kept airtight with an O-ring or the like.

Between the board installation stand 13 and the flange 15, as shown in Fig. 2(a)
As shown in FIG. 2(c), which is a cross-sectional view taken along line nn'' in FIG. 2(a), the first
A cylindrical or cylindrical spacer 17 is provided with a through hole 19 through which the rotating shaft 16 shown in the figure is inserted, and is installed so as to be in contact with the inner wall of the reaction tube 11 at a distance of about 10 mm. has been done.

As a modification of the spacer 17, it may be attached in an integral structure connected to the flange 15. A mercury liquid reservoir 1 is located between the substrate installation stand 13 and the spacer 17.
In order to maintain the temperature above 2, it can be heated with a heater 14A or the like.

In addition, the organometallic gas introduction pipe 21 such as diethyl cadmium or diethyl tellurium is made of quartz glass or the like that does not react with mercury vapor.
Attach it between 3 and 3. Between the mercury reservoir 12 and the organometallic gas introduction tube 21, a partition wall 22 for preventing backflow of organometallic gas with a plurality of holes in order to reduce the cross-sectional area of the reaction tube 11 is installed using quartz glass, carbon, etc. Make reaction tube 1 with
It is attached to the inner wall of 1.

The structure of this backflow prevention partition wall has a large number of through holes 19, as shown in the side view of FIG. .

As shown in FIG. 1, the carrier gas introduction tube 23 for evaporating the mercury in the liquid reservoir 12 is formed of a quartz glass tube or the like, and the nozzle at the tip of the gas introduction tube is used to evaporate the mercury in the liquid reservoir 12. 12 and is immersed below the surface of the liquid to bubble hydrogen.

In addition, in another embodiment of the gas inlet tube, as shown in FIG. In order to ensure stable supply, a structure may be adopted in which hydrogen is sprayed onto the surface of the liquid surface 24A of the mercury 24, avoiding large fluctuations in the liquid surface 24A of the mercury 24 due to bubbling.

In yet another embodiment, as shown in FIG. 4(c), in order to further stably supply mercury into the reaction tube, the outlet at the tip of the hydrogen gas blowout nozzle 23^ is connected to a watering can. The open end 25 may be provided with a large number of fine through holes like the structure of the tip.

As shown in FIG. 1 described above, a plurality of these hydrogen gas carrier gas introduction tubes 23 are provided, and in order to uniformly supply mercury to the reaction tube by adjusting the flow rate of the carrier gas flowing therein, each carrier gas is A flow rate adjusting means 26 such as a flow meter is attached to each gas introduction pipe 23.

Further, FIGS. 5(a) and 5(b) show the layout of the gas outlet of the organometallic gas introduction tube shown in FIG. 1.

FIG. 5(a) is a side view of the gas outlet of the gas introduction pipe, and FIG. 5(b) is a plan view thereof.

As shown in the figure, the gas outlet 21-1 of the organometallic gas inlet pipe 21 is connected to the rotating shaft 16 shown in FIG. Place it in a rotationally symmetrical position.

For example, in the figure, 2l-IA is the gas outlet of the diethyl tellurium gas inlet pipe, and 2l-IB is the gas outlet of the dimethyl cadmium gas inlet pipe.

In this way, the organometallic gas containing Cd or Te is mixed with mercury vapor at a uniform concentration.

Further, a mercury supply tank 28 is provided by connecting to the mercury liquid reservoir 12 shown in FIG.
2 is supplied with mercury to keep the mercury liquid level in the liquid reservoir 12 constant. Since the temperature of this mercury liquid reservoir 12 is comparatively high by -21=, heat is conducted from the mercury liquid reservoir 12, but the mercury temperature in the communication pipe 27 does not rise excessively due to convection or the like. Since the mercury supply tank 28 only needs to store relatively low-temperature mercury, it may have a structure in which the inside of the metal is coated with chemically stable ethylene fluoride.

In order to keep the mercury liquid level in the mercury reservoir 12 constant, it is necessary to keep the mercury liquid level in the mercury supply tank 28 constant.

FIG. 6 shows an embodiment of a mercury level meter 29 necessary for keeping the level of the mercury liquid level in the mercury supply tank 28 constant. A photodetector 33 having an array structure is combined. The height of the mercury liquid level 24^ is detected depending on which of the photodetecting elements 33^ in the array-structured photodetector the reflected light beam 32 reflected from the mercury liquid level 24A is incident on. It is something to do.

As a method of feeding back the signal from the mercury level meter 29 to maintain a constant height of the mercury liquid level in the mercury supply tank 28 shown in FIG. 34 is connected, and appropriate amounts of pulp in the mercury supply tank 28 and the mercury inlet pipe 35 of the mercury replenishment device 34 are opened and closed in accordance with the signal from the liquid level meter.

As another embodiment, in addition to using the mercury replenishment device, the communication pipe 27 may be made of fluoroethylene or a deformable pipe such as a pipe made of fluoroethylene with a fluoroethylene pipe inside a metal bellows. As shown in FIG. 7, the mercury supply tank 28 is equipped with a fixed rod 42 with teeth cut into one side, a gear 43 that meshes with the fixed rod, and a guide roll 44 that moves in conjunction with the gear.
Then, the above-mentioned raw material liquid supply tank 28 is installed on the installation stand 45 that moves according to this guide roll, and the installation stand 45 is rotated by a motor 46 that rotates the gear 43 to move the installation stand up and down, It is also possible to have a structure in which the height of the raw material liquid supply tank 28 is changed.

As described above, according to the crystal manufacturing apparatus of the present invention, the mercury reservoir 12 is disposed at the bottom of the vertical reaction tube 11, and by providing a structure for heating the reaction tube and the mercury reservoir, Mercury vapor is heavy, and the mercury concentration tends to increase as it goes downward. Therefore, supplying mercury to the substrate 18 from the downward side stabilizes the mercury concentration distribution and accurately controls the mercury partial pressure on the surface of the substrate 18 for epitaxial growth. Can be controlled.

The flange 15 on the gas discharge side is provided with a spacer 17 that is inscribed in the inner wall of the reaction tube 11 with a narrow interval and a heater 14A that heats this spacer, thereby reducing the backflow of gas. The same effect as when the entire inside of reaction tube 11 is raised to a high temperature is brought about, and the mercury partial pressure inside reaction tube 11 can be kept constant.

Then, the blowing nozzle 23A at the tip of the carrier gas introduction pipe 23 for hydrogen gas is immersed below the liquid surface of the mercury liquid reservoir 12, and hydrogen is bubbled or hydrogen is sprayed onto the mercury surface. By doing so, mercury can be supplied reliably and stably. Furthermore, by providing a plurality of hydrogen gas carrier gas introduction tubes 23 and providing a flow rate adjustment means 26 for each carrier gas introduction tube, mercury can be uniformly supplied to the reaction tube.

Furthermore, a mercury supply tank 28 is provided which is connected to the bottom of the mercury reservoir 12 through a communication pipe 27, and mercury is supplied from the outside of the reaction tube 11 to the mercury reservoir 12 to keep the mercury liquid level in the reservoir constant. By doing so, the amount of mercury evaporated from the liquid reservoir can also be stabilized. In particular, by using the liquid level meter 29 that uses a light source and a photodetector, the height of the mercury liquid level can be measured without contact, and mercury contamination can be prevented.

In addition, as a method of keeping the level of mercury in the mercury supply tank 28 constant, the mercury supply tank 2 is connected to a moving mechanism 41 that moves up and down.
By installing 8 and changing the height of the mercury supply tank, mercury contamination can be prevented.

Furthermore, by holding the crystal growth surface of the substrate 18 for epitaxial growth facing downward and facing the mercury reservoir 12, mercury is supplied from below, and the mercury concentration in the reaction tube 11 is determined by the height. Combined with this, it becomes easier to maintain a constant mercury concentration on the surface of the growth substrate. Furthermore, by rotating the substrate mounting table 13, the mercury concentration on the surface of the growth substrate can be made more uniform.

Furthermore, by providing the gas outlet 21-1 of the organometallic gas introduction tube 21 for supplying crystalline components other than mercury to the reaction tube between the mercury liquid reservoir 12 and the substrate installation stand 13, the mercury liquid reservoir 12 can reduce organometallic contamination.

Furthermore, by installing a pillar-shaped backflow prevention partition 22 with a plurality of holes between the mercury liquid reservoir 12 and the gas outlet of the organometallic gas introduction tube, a means for reducing the cross-sectional area of the reaction tube is provided. The backflow of organometallic gas can be prevented and the contamination of the mercury reservoir by organometals can be reduced.

Aim the outlet of the organometallic gas introduction tube in the direction in which the gas will be blown onto the growth surface of the epitaxial growth substrate.
By attaching the flow rate adjusting means 26 to each of the plurality of organometallic gas introduction tubes, the distribution of the amount of organometallic gas supplied to the growth substrate can be adjusted. By further rotating the substrate mounting table 13, the substrate 1 for epitaxial growth is
8. Uniform supply of organometallic gas to the surface becomes possible.

In particular, by arranging the outlets of different types of organometallic gas introduction tubes in rotationally symmetrical positions around the rotation axis of the substrate installation table, the supply amount for each organometallic component can be adjusted to the surface of the substrate for epitaxial growth. This makes it possible to control the distribution of organic metals, and it becomes possible to uniformly supply the organic metal to the surface of the growth substrate.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a mercury-based compound semiconductor crystal having a uniform composition can be manufactured with good reproducibility.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of the crystal manufacturing apparatus of the present invention, FIG. 2(a) and FIG. 2(c) are side views and cross-sectional views of the spacer of the present invention, and FIG. 3(a) 3(b) is a side view and a sectional view of the backflow prevention partition of the present invention, and FIG. 4(a) and 4(b) are explanatory diagrams of the structure of the tip of the carrier gas introduction pipe of the liquid reservoir. , Figures 5(a) and 5(c) are arrangement diagrams of the gas outlet of the organometallic gas inlet pipe, Figure 6 is an explanatory diagram of the liquid level meter of the present invention, and Figure 7 is the raw material liquid supply. An explanatory diagram of a tank moving mechanism, and FIGS. 8 and 9 are explanatory diagrams of a conventional crystal manufacturing apparatus. 46 indicates a motor. In the figure, 11 is a reaction tube, 12 is a liquid reservoir, 13 is a substrate installation stand, 14,
14A is a heater, 15 is a flange, 16 is a rotating shaft, 17
is a spacer, 1B is a substrate, 19 is a through hole, 21 is an organic metal gas introduction tube, 21-1.2l-IA, 2l-IB
is a gas outlet, 22 is a backflow prevention partition, 23 is a carrier gas introduction pipe, 23A is a blowout nozzle, 24 is mercury,
24A is a liquid level, 25 is an open end, 26 is a flow rate adjusting means,
27 is a communication pipe, 28 is a raw material liquid (water 1) supply tank, 29 is a liquid level needle, 31 is a light source, 32 is a reflected light beam, 33 is a photodetector, 33^ is a photodetecting element, 34 is a raw material liquid ( mercury)
Replenishment device, 35, mercury introduction tube, 36, valve, 41, moving mechanism, 42, fixed rod, 43, gear, 44, guide roll, 45, installation stand, 9 legs

Claims (11)

[Claims] (1) A vertical reaction tube (11) with a liquid reservoir (12) at the bottom containing a raw material liquid for epitaxial growth, and a substrate that can be installed facing the surface of the raw material liquid and can be rotated. a board installation stand (13); and a rotation means (20) connected to the board installation stand (13).
a rotating shaft (16) that transmits the rotation of the reaction tube (11), and a carrier gas introduction tube (2) that is inserted into the reaction tube (11) and introduces a carrier gas that evaporates the raw material liquid.
3); and an organometallic gas introduction tube (21) inserted into the reaction tube (11) between the substrate installation stand (13) and the liquid reservoir (12) to introduce an organometallic gas; A crystal manufacturing apparatus characterized in that a pipe (11) and a heating means (14) for heating the liquid reservoir (12) are provided. (2) The rotation shaft (16) is inscribed in the upper part of the substrate of the reaction tube (11) so that it can be inserted freely into the inner wall of the reaction tube at a predetermined interval, and supports and rotates the substrate installation stand (13) at the center. ) has a through hole (19) for inserting the reaction tube (1
The crystal manufacturing apparatus according to claim 1, further comprising a spacer (17) heated by the side heating means (14A) of claim 1). (3) An organometallic gas backflow prevention partition comprising a plurality of through holes (19) between the liquid reservoir (12) and the organometallic gas introduction tube (21) to reduce the internal cross-sectional area of the reaction tube (11). (2
2) The crystal manufacturing apparatus according to claim 1, further comprising: 2). (4) The tip of the carrier gas introduction pipe (23) is connected to the liquid reservoir (
12) is equipped with a blowing nozzle (23A) for blowing carrier gas onto the surface of the raw material liquid, or a liquid reservoir (12) is provided.
2) The crystal manufacturing apparatus according to claim 1, wherein the crystal manufacturing apparatus is immersed in the raw material liquid of claim 2). (5) The crystal manufacturing apparatus according to claim 1 or 4, wherein each of the carrier gas introduction pipes (23) is provided with a gas flow rate adjusting means (26). (6) The structure of the blow-off nozzle (23A) that blows the carrier gas onto the surface of the raw material liquid in the liquid reservoir (12) is an open end (25) with a plurality of carrier gas blow-off holes like the tip structure of a watering can. The crystal manufacturing apparatus according to claim 1 or 4, characterized in that it has the following. (7) A plurality of organometallic gas introduction tubes (21) are provided with flow rate adjustment means (26), and the gas outlet (21-1) at the tip of the gas introduction tube is arranged on the growth surface of the substrate. 2. The crystal manufacturing apparatus according to claim 1, wherein the crystal manufacturing apparatus is capable of blowing gas toward the crystal. (8) Gas outlet of organometallic gas inlet pipe (21) (
21-1) is arranged at a rotationally symmetrical position about the rotation axis (16) of the substrate installation table (13), or (7). Device. (9) A raw material liquid supply tank (28) connected to the liquid reservoir (12) by a communication pipe (27) is provided outside the reaction tube (11), and the raw material liquid in the raw material liquid supply tank (28) is A liquid level meter (29) for raw material liquid, which is composed of a light source (31) that makes a light beam obliquely incident on the surface, and a photodetector (33) that detects the reflected light beam (32) of the light beam on the liquid surface of the raw material liquid. ) The crystal manufacturing apparatus according to claim 1, further comprising: (10) The communication pipe (27) is formed of a deformable flexible pipe, and the raw material liquid supply tank (28) can be moved up and down according to the signal from the raw material liquid level meter (29). Claim (1) characterized by comprising a moving mechanism (41).
), or the crystal manufacturing apparatus according to (9). (11) A raw material liquid replenishment device (34) is connected to the raw material liquid supply tank (28), and a raw material liquid level meter (29) is provided.
), the raw material liquid is transferred to the raw material liquid supply tank (28
), and the liquid level of the raw material liquid in the raw material liquid supply tank (28) is kept constant. .