JP2713347B2 - Vapor phase crystal growth equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vapor-phase crystal growth apparatus for growing a compound semiconductor epitaxial crystal on a substrate by flowing a source gas together with a carrier gas from upstream to downstream. More particularly, the present invention relates to a vapor phase crystal growth apparatus improved so as to obtain a steep hetero interface.

[Prior Art] Compound semiconductor heteroepitaxial crystals are widely used as crystal materials for optoelectronic devices and ultrahigh-speed electronic devices.

FIG. 8 schematically shows the internal structure of a reaction tube of a conventional vapor phase crystal growth apparatus for producing a heteroepitaxial crystal. Referring to FIG. 8, reference numeral 2 denotes a reaction tube. An electric furnace (heating furnace) 1 is arranged around the reaction tube 2. A substrate 3 is accommodated in the reaction tube 2. The substrate 3 is supported by a substrate holder 4. On the upstream side 10 in the reaction tube 2, a first vapor growth chamber 6 and a second vapor growth chamber 5 for growing a compound semiconductor epitaxial crystal on the substrate 3 are provided. On the downstream side 11 in the reaction tube 2, there is provided a communication chamber 9 that connects the downstream ends of the first vapor-phase growth chamber 6 and the second vapor-phase growth chamber 5 to each other. The first vapor growth chamber 6 is connected to a first raw material gas introduction pipe 6 a for feeding a first raw material gas and a carrier gas into the first vapor growth chamber 6. The second vapor-phase growth chamber 5 is connected to a second raw-material gas introduction pipe 5 a for feeding a second raw-material gas and a carrier gas into the second vapor-phase growth chamber 5. In the figure,
Arrow 7 indicates the flow of the second source gas necessary for epitaxial growth. Arrow 8 indicates the flow of the first source gas required for epitaxial growth.
An exhaust pipe 9a is connected to the communication room 9. The first source gas is supplied from the first source gas inlet pipe 6a to the first gas phase growth chamber 6.
Inside, pass through the communication room 9 and exit through the exhaust pipe 9a. The second source gas enters the second vapor phase growth chamber 5 from the second source gas introduction pipe 5a, passes through the communication chamber 9, and passes through the exhaust pipe 9a.
Get out of.

Next, a method of manufacturing a substrate on which a heteroepitaxial crystal is grown as shown in FIG. 9 using this apparatus will be described. In FIG. 9, reference numeral 12 denotes a substrate. substrate
A first compound semiconductor epitaxial layer 13 made of InP is formed on 12, and a second compound semiconductor epitaxial layer 14 made of InGaAs is formed thereon.

Returning to FIG. 8, a source gas required for forming InP is introduced into the first vapor growth chamber 6 from the first source gas introduction pipe 6a. Next, the second source gas introduction pipe 5a
Thus, a second source gas necessary for forming InGaAs is introduced into the second vapor deposition chamber 5. Next, the substrate 3 supported by the substrate holder 4 is inserted into the first vapor deposition chamber 6. Then, the first compound semiconductor epitaxial layer 13 made of InP grows on the substrate 12. Next, the substrate 3 is pulled out into the communication chamber 9 and rotated by 180 ° to form the second vapor deposition chamber 5.
Insert into Then, a second compound semiconductor epitaxial layer 14 made of InGaAs is formed on the first compound semiconductor epitaxial layer 13.

[Problems to be Solved by the Invention] Since the conventional vapor phase growth apparatus is configured as described above, referring to FIG. 8, the communication chamber 9 located on the downstream side 11 is made of InP and InGaAs. Source gas is flowing in an uncontrolled manner. In the process of transferring the substrate 3 from the first vapor growth chamber 6 to the second vapor growth chamber 5 for the growth of InGaAs after the growth of InP, the time during which the substrate passes through the communication chamber 9 is several seconds. It is. However, during this time, there is a problem that the transition layer whose composition is not controlled grows by about 40 °, and the quality of the hetero interface deteriorates.

The present invention has been made to solve the above-described problems, and has as its object to provide a vapor-phase crystal growth apparatus capable of obtaining a steep heterointerface.

[Means for Solving the Problems] The present invention relates to a vapor phase crystal growth apparatus for growing a compound semiconductor heteroepitaxial crystal on a substrate by flowing a source gas together with a carrier gas from upstream to downstream. The apparatus includes a reaction tube that accommodates a substrate. Downstream of the reaction tube, a first vapor growth chamber and a second vapor growth chamber for growing a compound semiconductor epitaxial crystal on a substrate in the chamber are provided. A communication chamber that connects the upstream ends of the first and second vapor-phase growth chambers to each other is provided upstream of the reaction tube.
The communication chamber is connected to a carrier gas introduction means for sending a carrier gas into the reaction tube. A first source gas introducing means for feeding a first source gas into the first vapor deposition chamber is connected to the first vapor deposition chamber. The second vapor phase growth chamber is provided with a second raw material gas introducing means for feeding a second raw material gas into the second vapor phase growth chamber. Then, the apparatus inserts the substrate into the first vapor deposition chamber,
Next, after the compound semiconductor epitaxial crystal is grown on the substrate, the substrate is drawn into the communication chamber, and thereafter, there is provided driving means for inserting the substrate into the second vapor phase growth chamber.

[Operation] According to the present invention, after forming the first compound semiconductor epitaxial layer on the substrate in the first vapor phase growth chamber, the substrate is drawn into the communication chamber. In the present invention, since the communication chamber is provided on the upstream side in the reaction tube, only the carrier gas is filled in the communication chamber, and no source gas exists. Therefore, even if the substrate on which the first compound semiconductor epitaxial layer is formed is drawn into the communication chamber, a transition layer whose composition is not controlled unlike the related art is not formed. Therefore, next, when the substrate is transferred from the communication chamber to the second vapor phase growth chamber to form the second compound semiconductor epitaxial layer on the first compound semiconductor epitaxial layer,
One having a steep hetero interface is obtained.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a vapor phase crystal growth apparatus according to one embodiment of the present invention, and FIG. 2 is a sectional view taken along the line II-II in FIG. Referring to these drawings, the vapor phase crystal growth apparatus according to the embodiment includes a reaction tube 2. Reaction tube 2
A first vapor growth chamber 6 and a second vapor growth chamber 5 are provided on the downstream 11 side. The first vapor deposition chamber 6 and the second vapor deposition chamber 5 are separated by a partition plate 15. On the upstream 10 side in the reaction tube 2, a communication chamber 9 for connecting the upstream ends of the first vapor growth chamber 6 and the second vapor growth chamber 5 to each other is provided. The downstream ends of the first vapor deposition chamber 6 and the second vapor deposition chamber 5 are connected to an exhaust port 19. The communication chamber 9 is connected to a carrier gas introduction pipe 16 for sending a carrier gas (H ₂ gas) into the reaction tube 2. In the first vapor growth chamber 6, for example, a first InP
A first source gas introduction pipe 17 for feeding the source gas into the first vapor phase growth chamber 6 is connected. A second source gas introduction pipe 18 for feeding a second source gas such as IGaAs into the second vapor phase growth chamber 5 is connected to the second vapor phase growth chamber 5. A substrate 3 is accommodated in the reaction tube 2. The substrate 3 is held by a substrate holder 4. The substrate holder 4 is connected to a support rod 24. The support rod 24
It is connected to driving means (not shown) so that it can reciprocate in the direction of arrow AB. Further, the support rod 24 is connected to a driving means (not shown) so as to rotate about its axis.

The carrier gas that has entered the communication chamber 9 from the carrier gas introduction pipe 16 flows in the direction indicated by the arrow 20 (the direction from the upstream to the downstream), and flows into the first vapor growth chamber 6 and the second vapor growth chamber 5. And is discharged to the outside through the exhaust port 19. The first source gas entered from the first source gas introduction pipe 17 flows through the first vapor phase growth chamber 6 to the outside through the exhaust port 19. The second source gas that has entered through the second source gas inlet pipe 18 is the second source gas.
Flows out of the exhaust port 19 through the vapor phase growth chamber 5.

Next, a method for growing a heteroepitaxial crystal on a substrate using the above-described apparatus will be described.

H ₂ gas, which is a carrier gas, is introduced into the communication room 9 from the carrier gas introduction pipe 16. A first source gas of, for example, InP is introduced into the first vapor growth chamber 6 from the first source gas introduction pipe 17. A second source gas of, for example, InGaAs is introduced into the second vapor phase growth chamber 5 from the second source gas introduction pipe 18. In such a state, the substrate 3 is
Is introduced into the vapor phase growth chamber 6. Then, InP is placed on the substrate 3.
Epitaxial crystal grows. Next, referring to FIG. 3, the support rod 24 is pulled up in the direction of the arrow A (that is, upstream), and the substrate 3 is pulled out into the communication chamber 9. Thereafter, the support bar 24 is rotated by 180 ° in the direction of arrow R, and then the support bar 24 is pulled down in the direction of arrow B. Then, the substrate 3 is inserted into the second vapor deposition chamber 5. Thus, already formed
An InGaAs epitaxial crystal grows on the InP epitaxial crystal.

According to the present embodiment, referring to FIG. 3, after forming a first compound semiconductor epitaxial layer on substrate 3 in first vapor phase growth chamber 6, substrate 3 is drawn out into communication chamber 9. Since the communication chamber 9 is provided on the upstream side in the reaction tube 2, the communication chamber 9 is filled only with hydrogen gas as a carrier gas, and there is no source gas. Therefore, even if the substrate on which the first compound semiconductor epitaxial layer is formed is pulled into the communication chamber 9, a transition layer whose composition is not controlled is not formed as in the related art. Therefore, the next time the substrate 3 is transferred from the communication chamber 9 to the second vapor phase growth chamber 5 to form the second compound semiconductor epitaxial layer on the first compound semiconductor epitaxial layer, Is obtained.

FIG. 5 is a sectional view of another embodiment of the present invention, and FIG. 6 is a sectional view taken along the line VI-VI in FIG. The embodiment shown in FIGS. 5 and 6 has the following exceptions.
This embodiment is the same as the embodiment shown in FIGS. 1 and 2, and the corresponding parts are denoted by the same reference numerals and the description thereof will be omitted.

In the embodiment shown in FIG. 5 and FIG.
On the downstream side 11 are a first vapor growth chamber 20, a second vapor growth chamber 21, a third vapor growth chamber 22, and a fourth vapor growth chamber 23.
Is provided. The first vapor growth chamber 20 is provided to face the third vapor growth chamber 22, and the second vapor growth chamber 21 is
Is provided opposite to the vapor phase growth chamber 23 of FIG.

A first source gas introduction pipe 17 for introducing a first source gas of, for example, InP is connected to the first vapor phase growth chamber 20, and the first vapor phase growth chamber 22 is also provided with a first source gas introduction pipe 17 (not shown). Are connected. A second source gas introduction pipe 18 for introducing a second source gas of, for example, InGaAs is connected to the second vapor phase growth chamber 21. Are connected. Support rod
On 24, substrate holders 4a and 4b for holding the substrate 3 are supported. The substrate holder 4a and the substrate holder 4b are arranged so as to be symmetrical with respect to the support rod 24.

Next, the operation of crystal growth will be described. H ₂ gas as a carrier gas is supplied from the carrier gas inlet pipe 16 to the communication room 9.
Pour in From the first source gas introduction pipe 17, for example, InP
Is introduced into the first vapor phase growth chamber 6.
A second source gas of, for example, InGaAs is introduced into the second vapor phase growth chamber 5 from the second source gas introduction pipe 18. Next, the support rod 24 is pushed down in the direction of arrow B, and the substrate 3a held by the substrate holder 4a is inserted into the first vapor deposition chamber 20. At this time, the substrate 3b held by the substrate holder 4b is also
Is inserted into the vapor phase growth chamber 22. Thus, a first compound semiconductor epitaxial layer of, for example, InP is formed on the substrate 3a and the substrate 3b. Thereafter, the support rod 24 is pulled up in the direction of arrow A, and the substrates 3a and 3b
Pull out inside. Since the communication chamber 9 is provided on the upstream side in the reaction tube 2, the communication chamber 9 is filled only with hydrogen gas as a carrier gas, and there is no source gas.
Therefore, even if the substrates 3a and 3b on which the first compound semiconductor epitaxial layers are formed are pulled into the communication chamber 9, a transition layer whose composition is not controlled is not formed as in the related art. Next, the support bar 24 is rotated by 90 ° and pushed down in the direction of arrow B. As a result, the substrate 3a is inserted into the second vapor growth chamber 21, and the substrate 3b is inserted into the fourth vapor growth chamber 23, and the state shown in FIG. 7 is realized. Since the second source gas such as InGaAs is introduced into the second vapor-phase growth chamber 21 and the fourth vapor-phase growth chamber 23, the substrate 3a on which the first compound semiconductor epitaxial layer is formed is formed. For example, the second InGaAs
A compound semiconductor epitaxial layer of
Substrate on which first compound semiconductor epitaxial layer is formed
A second compound semiconductor epitaxial layer is formed on 3b.

Also in this embodiment, since a transition layer whose composition is not controlled is not formed as in the prior art, a device having a steep hetero interface can be obtained.

In the embodiment shown in FIGS. 5 and 6,
Since two substrates can be processed at the same time, an effect that productivity is further improved is produced.

Note that, in the above embodiment, the case where a compound semiconductor heteroepitaxial crystal composed of a binary compound semiconductor epitaxial crystal such as InP and a ternary compound semiconductor epitaxial crystal such as InGaAs is grown is described as an example.
The apparatus can be applied to the growth of a quaternary compound semiconductor epitaxial crystal such as GaAsP.

Further, in the above-described embodiment, the case where the number of the vapor phase growth chambers is two or four is exemplified, but the number can be further increased.

Further, in the above-described embodiment, a vertical device has been exemplified. According to this, InP etc. have a high specific gravity, and I
This has an effect that nP or the like is not mixed at all. However, the present invention is not limited to this, and may be a horizontal device.

Although the present invention has been described with reference to specific embodiments, the preferred embodiments described in this specification are illustrative and not restrictive. The scope of the invention is defined by the appended claims, and all modifications that come within the meaning of the claims are intended to be covered by the present invention.

According to the present invention, after forming a first compound semiconductor epitaxial layer on a substrate in a first vapor phase growth chamber, the substrate is drawn out to a communication chamber. Since the communication chamber is provided on the upstream side in the reaction tube, the communication chamber is filled only with the carrier gas and there is no source gas. Therefore, even if the substrate on which the first compound semiconductor epitaxial layer is formed is drawn into the communication chamber, a control layer whose composition is not controlled is not formed as in the related art. Therefore, when the substrate is transferred from the communication chamber to the second vapor-phase growth chamber to form the second compound semiconductor epitaxial layer on the first compound semiconductor epitaxial layer, the substrate has a steep hetero interface. The effect that a thing is obtained is produced. Therefore, electrical,
It is expected that the optical characteristics disappear and contribute to the improvement of various device characteristics.

[Brief description of the drawings]

FIG. 1 is a sectional view of one embodiment of the present invention. FIG. 2 is a sectional view taken along the line II-II in FIG. Third
FIG. 4 and FIG. 4 are diagrams for explaining the operation of the apparatus according to the embodiment shown in FIG. FIG. 5 is a sectional view of a vapor phase crystal growth apparatus according to another embodiment of the present invention. Sixth
The figure is a sectional view taken along the line VI-VI in FIG. FIG. 7 is a view when the substrate is moved in the embodiment shown in FIG. FIG. 8 is a schematic view of a conventional vapor phase crystal growth apparatus. FIG. 9 is a sectional view of a substrate on which a compound semiconductor heteroepitaxial crystal has grown. In the figure, 2 is a reaction tube, 3 is a substrate, 4 is a substrate holder,
Reference numeral 5 denotes a second vapor phase growth chamber, 6 denotes a first vapor phase growth chamber, 9 denotes a communication chamber, 10 denotes an upstream side, 11 denotes a downstream side, 16 denotes a carrier gas introduction pipe, and 17 denotes a first source gas introduction. A tube, 18 is a second source gas introduction tube, and 24 is a support rod.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Katayama, 1-1-1 Kunyokita, Itami-shi, Itami-shi, Hyogo Sumitomo Electric Industries, Ltd. Itami Works (56) Reference JP-A-63-73616 (JP, A JP-A-2-32531 (JP, A)

Claims (1)

(57) [Claims] 1. A vapor phase crystal growth apparatus for flowing a source gas together with a carrier gas from upstream to downstream to grow a compound semiconductor epitaxial crystal on a substrate, comprising: a reaction tube accommodating the substrate; A first vapor phase growth chamber and a second vapor phase growth chamber provided on the downstream side for growing the compound semiconductor epitaxial crystal on the substrate in the chamber; and A communication chamber interconnecting the upstream ends of the first and second vapor deposition chambers; and a carrier gas introducing means connected to the communication chamber and feeding the carrier gas into the reaction tube. A first source gas introduction unit connected to the first vapor phase growth chamber to feed a first source gas into the first vapor phase growth chamber; and a first source gas introduction unit connected to the second vapor phase growth chamber; The second source gas is supplied to the second gas. Second source gas introducing means for feeding into the growth chamber; and inserting the substrate into the first vapor phase growth chamber; and then, after growing the compound semiconductor epitaxial crystal on the substrate, moving the substrate into the communication chamber. And a driving unit for inserting the substrate into the second vapor phase growth chamber, and then driving the substrate into the second vapor phase growth chamber.