JPH10223539A - Organic metal vapor growth method and its vapor growth device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure of a device by connecting at least two organic metal feed gases in the same family to a reaction pipe where a substrate under processing of an organic metal vapor growth device is arranged, merging it to a reactor line where a carrier gas is supplied before starting to supply, and supplying it to the reaction pipe where the substrate is arranged. SOLUTION: An organic metal gas taken out of organic metal gas take-out pipes 141, 142, 143, and 144 merge at merging parts 301 and 302 before the gases reach a reactor line 22. The merged organic metal feed gases are guided to the reactor line 22 and are fed to a reaction pipe 13 for performing a final target vapor growth. Then, a first semiconductor film made of AlGaAs is formed by the feed gas of a first raw material system 1 and a second semiconductor made of AlGaAs with a different ratio of elements for constituting a semiconductor film by a second raw material system 2 is formed. A cost can be reduced by simplifying the structure of an organic metal vapor growth device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metalorganic vapor phase epitaxy method and a vapor phase epitaxy apparatus therefor.

[0002]

2. Description of the Related Art For example, an LED (Light Emitting Diod)
e), HEMT (High Electron Mobility Transistor)
In various semiconductor device devices including compound semiconductors, for example, epitaxial growth, metal organic chemical vapor deposition (hereinafter, referred to as MOCVD) which can control supply of raw materials accurately and reproducibly, Molecular beam epitaxy (MBE) is suitable. Further, these methods are characterized by crystal growth in a non-equilibrium state, and can obtain a multi-component compound semiconductor mixed crystal which is difficult by liquid phase growth. In particular, in the MOCVD apparatus, the scale can be easily increased, and the compound semiconductor can be efficiently and easily grown.

FIG. 2 is a schematic view of a conventional MOCVD apparatus having a plurality of metal organic source gas supply sources. For example, A
When performing epitaxial growth of the lGaAs compound semiconductor layer by the MOCVD method, organic metal source gas supply sources 61 to 64 for obtaining an organic metal source gas of trimethylgallium (TMGa) and trimethylaluminum (TMAl) as the group III source are provided. , V source material supply source 32 is provided with arsine (AsH ₃ ). In this case, for the organometallic raw material gas supply sources 61 to 64, for example, 61 and 63 are replaced by trimethylgallium (TMGa).
, 62 and 64 as trimethylaluminum (TMA
l) can be a source.

The organic metal raw material gas supply sources 61 to 64 contain the above-mentioned liquid organic metal raw materials (not shown), respectively, and contain hydrogen carrier purified by a purifying device (not shown). The flow rate of the carrier gas from the gas supply source 12 is controlled through mass flow controllers (MFCs) 81 to 84 so that the carrier gas supply pipes 51 are respectively provided.
To 54, and bubbling is performed to take out the organometallic raw material gas together with the carrier gas from the organometallic raw material gas take-out tubes 41 to 44, and transfer them to a reaction tube on which a substrate on which metalorganic vapor phase epitaxy is performed is arranged. connection,
Leading to the reactor line 22 where the carrier gas is supplied,
Finally, it is led to a reaction tube 13 for performing a target vapor phase growth.

The organometallic raw material gas thus sent into the reaction tube 13 is heated by a heating means 14 such as a high-frequency coil or the like to a substrate 16 on a susceptor 15 maintained at a constant temperature.
Where thermal decomposition occurs to perform epitaxial growth of the target compound semiconductor layer on the substrate 16.

On the other hand, when the epitaxial growth is to be stopped, the supply of the carrier gas to the organic metal source gas supply sources 61 to 64, that is, the supply of the organic metal source gas to the reaction tube 13 may be stopped. ,
When the pressure in the reaction tube 13 changes, the quality of the compound semiconductor layer grown on the substrate 16 may be deteriorated and the composition may be changed.

Therefore, in order to keep the pressure inside the reaction tube 13 constant, as shown in FIG.
Through a reaction tube 13 and an exhaust passage, a so-called vent line (Ve
nt Line) 21, valves 71a-74a and 71b
A dummy line 20 of the carrier gas which is switched by the switching means 71 to 74 of the carrier gas is provided. The flow rate of the dummy carrier gas is set according to the flow rate of the organometallic source gas required for forming the compound semiconductor layer. On the other hand, the organometallic source gas from the organometallic source gas supply sources 61 to 64 can also be switched and sent to the reaction tube 13 and the vent line 21 by the valves 71a to 74a and 71b to 74b of the switching means 71 to 74. To do.

The dummy line 20 of the carrier gas is supplied to the vent line 21 when the epitaxial growth is performed by operating the valves 71a to 74a and 71b to 74b. Are the valves 71a-
By switching between 74a and 71b to 74b, a dummy carrier gas is switched, and a dummy carrier gas is flown into the reaction tube 13, and the organometallic raw material gas is caused to flow to the vent line 21. Even when the supply is stopped, the pressure in the reaction tube 13 does not change.

In order to more reliably perform the operation for keeping the pressure in the reaction tube 13 constant, the carrier line 12 shown in FIG.
The carrier gas is also supplied to the sub-line 120 connected to the second line. Then, the mass flow controller 1
07, the pressure in the reaction tube 13 is kept constant together with the carrier gas in the dummy line 20.

[0010] Also, organometallic raw material gas extraction pipes 41-41
44, piezo valves 501 to 5 incorporating a piezoelectric element.
By arranging 04, the amount of the organic metal source gas can be controlled more precisely.

A mass flow controller (MFC)
The flow rates of the organic metal raw material gas supply sources 61 to 61 are controlled through carrier gas supply pipes 51 to 54, respectively.
Since a relatively small amount of hydrogen is blown into the chamber 64, the carrier gas push-out lines 131 to 134 increase the gas velocity of the organometallic raw material gas generated by the bubbling and push the gas into the reactor line 22.
Mass flow control 101 to 10
4. Controlled flow.

As described above, the epitaxial growth can be performed without changing the pressure in the reaction tube 13 while preventing the deterioration of the film quality and the fluctuation of the composition.

[0013]

However, in general, in MOCVD, for example, on AlGaAs,
When growing an AlGaAs semiconductor film having a different ratio of constituent elements or a different kind of semiconductor film, it is necessary to change the organometallic raw material gas supplied into the reaction tube 13 and change the supply amount thereof. Each time, a pipe is installed for each raw material, and valves 71a to 74a and 71b to 74b of switching means 71 to 74 for switching the carrier gas and the organometallic raw material gas to the vent line 21 and the reactor line 22; It is necessary to install a mass flow controller (MFC) for controlling the flow rate of the carrier gas and the like, so that the entire apparatus has a very complicated configuration.

On the other hand, the conventional MOC shown in FIG.
In the VD apparatus, each of the organometallic raw material gases is divided into a vent line 21 and a reactor line 22 so as to flow. In this case, an extremely small amount is supplied from any of the organometallic raw material gas supply sources. When the organometallic raw material gas needs to be sent out to the reactor line 22, the organometallic raw material gas is not supplied at a sufficient speed to reach the reaction tube 13. There is.

Further, in order to produce a semiconductor film having a multilayer structure having a different composition, it is necessary to switch and supply a necessary organometallic raw material gas for each layer of the produced semiconductor film. Each time the raw material gas is switched for each layer, the organic metal raw material gas in the organic metal raw material supply source located at a position separated from the reaction tube 13 is slower in reaching the reaction tube 13, so that the substantial supply of the supply gas is performed. The ratio may deviate from the predetermined supply ratio, and as a result, the composition of the semiconductor film may fluctuate or the film quality may deteriorate.

Therefore, in the present invention, the structure of the MOCVD apparatus is simplified, and the flow rates of the organometallic raw material gas and the carrier gas can be controlled simply. When it is generated, the organic metal source gas required for each semiconductor layer is simultaneously supplied to the reaction tube 13.
, And the organic metal source gas can be sufficiently distributed to the reaction tube 13. As a result, the composition and film quality of the semiconductor film are improved.

[0017]

The metalorganic vapor phase epitaxy method of the present invention comprises connecting each of two or more homologous metalorganic source gases to a reaction tube in which a substrate on which metalorganic vapor phase epitaxy is performed is arranged. Are combined before supply to a reactor line to which a carrier gas is supplied, and supplied to a reaction tube in which a substrate on which metalorganic vapor phase epitaxy is performed is arranged.

Further, in the metalorganic vapor phase epitaxy apparatus of the present invention, a supply source of at least two organic metal source gases of the same family is provided, and the source gas from each metal organic source gas is supplied from the organic metal source gas. A junction is provided, which is connected to a reaction tube in which a substrate on which vapor phase growth is to be performed is arranged and is joined before supply to a reactor line to which a carrier gas is supplied.

According to the present invention, the structure of the MOCVD apparatus can be simplified by merging two or more organic metal source gases of the same family before supplying them to the reactor line.

[0020] Further, by combining two or more organic metal raw material gases of the same family before supply to the reactor line, a large flow rate of the organic metal raw material gas can be sent to the reactor line. The control of the flow rates of the gas and the carrier gas can be performed simply.

Further, a sufficient amount of the organic metal source gas required for forming the semiconductor film can be distributed to the reaction tube for each of the organic metal source gases required for forming each semiconductor film. As a result, a semiconductor film having a multilayer structure in which the composition change at the interface between the layers is sharp can be formed.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the metal organic chemical vapor deposition method and the metal organic chemical vapor deposition apparatus of the present invention will be described.

FIG. 1 is a schematic structural view of a metal organic chemical vapor deposition apparatus according to the present invention. In this example, Al _x Ga _{1 -x} A
compound semiconductor layer of the structure of _{s / Al y Ga 1-y} As (x ≠ y), i.e., in the first layer and the second layer, when the proportion of elements constituting were different, epitaxial growth by MOCVD Will be described.

In this case, as the group III raw material, trimethyl gallium (TMGa), trimethyl aluminum (T
Metal organic source gas supply sources 161 and 162 for obtaining an organic metal source gas of MAl) are provided, and these are referred to as a first raw material system 1.

Further, metal metal source gas supply sources 163 and 164 for obtaining an organic metal material gas of trimethylgallium (TMGa) and trimethylaluminum (TMAl) are provided while changing the ratio from the first material system. Second
Of raw material system 2.

In this case, arsine (AsH ₃ ) is provided as the group V raw material supply source 32.

In the MOCVD apparatus according to the present invention, the first raw material system 1 is used to form a group III organometallic raw material necessary for forming an AlGaAs semiconductor film, ie, trimethylgallium (TMGa) or trimethylaluminum (TMAl). Before the metal raw material gas reaches the reactor line 22, the merging section 3
01 is provided. Here, the reactor line 22 is
This is a line connected to a reaction tube on which a substrate on which metal organic chemical vapor deposition is to be performed is arranged and to which a carrier gas is supplied. In FIG. 1, the line is indicated by a dotted line.

The second raw material system 2 allows AlGa
Group III organometallic raw materials necessary for forming an As semiconductor film, that is, trimethylgallium (TMGa) and trimethylaluminum (TMAl) organic metal source gases are
Before reaching the reactor line 22, a merging portion 302 is provided so as to merge.

Each organic metal source gas supply source 1 shown in FIG.
Numerals 61 to 164 transfer mass-purified carrier gas from the hydrogen carrier gas supply source 12 by a purifying device (not shown) to mass flow controllers (MFC) 181 to 184.
Through the carrier gas supply pipe 1
The organic metal raw material gas is blown from 51 to 154 and bubbling is performed to take out the organic metal raw material gas together with the carrier gas from the organic metal raw material gas extraction pipes 141 to 144.

As described above, the organometallic raw material gases taken out of the organometallic raw material gas take-out pipes 141 and 142 join at the junction 301 before these gases reach the reactor line 22.

Further, an organic metal raw material gas extraction pipe 143
Similarly, the organometallic raw material gases taken out of the reactor 144 also merge at the junction 302 before reaching the reactor line 22.

The organometallic raw material gas (organometallic raw material gas from the first raw material system 1) merged at the junction 301 is
It is led to a reactor line 22 and finally sent to a reaction tube 13 for performing a target vapor phase growth.

Also, the organometallic source gas (organic metal source gas from the second source system 2) that has merged at the junction 302 is led to the reactor line 22 and finally undergoes the intended vapor phase growth. It is sent to the reaction tube 13.

The organometallic raw material gases of the first raw material system 1 and the second raw material system 2 sent into the reaction tube 13 are respectively heated on a susceptor 15 maintained at a constant temperature by a heating means 14 such as a high-frequency coil. Is transferred to the substrate 16, where thermal decomposition is caused to cause epitaxial growth of the target compound semiconductor layer on the substrate 16. That is, in this example, the first semiconductor film of AlGaAs is formed by the organometallic raw material gas of the first raw material system 1,
Using the second raw material system 2, a second semiconductor film made of AlGaAs having different ratios of elements constituting the semiconductor film is formed.

On the other hand, when the epitaxial growth is stopped, the supply of the carrier gas to the organic metal source gas supply sources 161 to 164, that is, the supply of the organic metal source gas to the reaction tube 13 may be stopped. When the pressure in the reaction tube 13 changes, the substrate 16
In some cases, the film quality of the compound semiconductor layer grown thereon may be degraded and the composition may be changed.

In order to keep the pressure inside the reaction tube 13 constant, as shown in FIG.
Through a reaction tube 13 and an exhaust passage, a so-called vent line (V).
ent Line) 21 and switching means 171 and 1 for valves 171a, 172a and 171b, 172b.
A dummy line 20 of the carrier gas switched by 72 is provided. The flow rate of the carrier gas in the dummy line 20 is set according to the flow rate of the organic metal source gas required for forming the compound semiconductor layer.

On the other hand, the organic metal raw material gas supply sources 161-1
For the organometallic raw material gas from No. 64, the valve 171 is also used.
a, 172a and 171b, 172b by means of switching means 171 and 172 so that they can be switched and sent to the reaction tube 13 and the vent line 21.

The dummy line 20 for the carrier gas is supplied to the vent line 21 when the epitaxial growth is performed by operating the valves 171a and 172a and the valves 171b and 172b. Is switched to a dummy carrier gas by switching valves 171a, 172a and 171b, 172b so that a dummy carrier gas flows in the reaction tube 13 and an organometallic raw material gas flows to the vent line 21, Even when the supply of the organometallic raw material gas is stopped, the reaction tube 13
The pressure inside is kept unchanged.

In order to more reliably perform the operation for maintaining the pressure in the reaction tube 13 constant, the carrier gas supply source 12 shown in FIG.
The carrier gas is also supplied to the sub-line 120 leading to. Then, the flow rate is determined by the mass flow controller 10
7, the pressure inside the reaction tube 13 is kept constant together with the carrier gas in the dummy line 20.

In the vicinity of the junctions 301 and 302,
Piezo valves 401 and 402 incorporating a piezoelectric element
Is arranged, the amount of the organic metal source gas can be controlled more precisely.

A mass flow controller (MFC)
The amount of hydrogen blown into the organic metal source gas supply sources 161 to 164 from the carrier gas supply pipes 151 to 154 by controlling the flow rate through 181 to 184 is relatively small. To increase the gas velocity of each of the junctions 301 and 3
Since it is necessary to extrude the carrier gas into the carrier gas, the carrier gas is desirably controlled by the mass flow controllers 201 and 202 to flow through the carrier gas pushing lines 231 and 232.

According to the above-described embodiment, when growing a group III-V compound semiconductor, II
Although elements of Group I and Group V elements were used, the present invention is not limited to this example, and materials of Group II and Group VI elements may be used as raw materials for growing II-VI group compound semiconductors. The same effect can be obtained also when using.

Further, in the above-described embodiment, the case where a ternary mixed crystal semiconductor film is formed has been described. However, the present invention is not limited to this example. When applicable.

In the metalorganic vapor phase epitaxy method of the present invention, a substrate on which metalorganic vapor phase epitaxy is performed by combining two or more homologous metalorganic source gases before supply to a reactor line is arranged. Is supplied to the reaction tube.

Further, the metal organic chemical vapor deposition apparatus of the present invention
Providing a supply source of at least two organic metal source gases of the same family,
The source gas from each metal organic source gas supply source is connected to the reaction tube where the substrate on which metal organic chemical vapor deposition is to be performed is connected to the reaction tube where the carrier gas is supplied. It is provided.

According to the present invention, the structure of the MOCVD apparatus can be simplified by merging two or more organic metal raw material gases of the same family before supplying them to the reactor line. Thus, the number of pressure control devices can be reduced, and the cost can be reduced.

Further, by combining two or more organic metal raw material gases of the same family before supplying them to the reactor line, a larger flow rate of the organic metal raw material gas than before can be sent to the reactor line. The flow rate of the organic metal source gas and the carrier gas can be controlled simply,
The material can be rapidly switched when the semiconductor film is formed.

Further, a sufficient amount of the organic metal source gas necessary for forming the semiconductor film can be simultaneously and simultaneously reach the reaction tube in a sufficient amount for each of the organic metal source gases constituting each semiconductor film. As a result, a semiconductor film having a multilayer structure in which the composition change at the interface between the layers is sharp can be formed.

[0049]

According to the present invention, the structure of the MOCVD apparatus can be simplified by merging two or more organic metal source gases of the same family before supplying them to the reactor line. As a result, the number of parts, pipes, and pressure control devices can be reduced, and costs can be reduced.

Further, by combining two or more organic metal raw material gases of the same family before supply to the reactor line, a large flow rate of the organic metal raw material gas can be sent to the reactor line. The flow rate of the gas and the carrier gas could be controlled simply.

In addition, a sufficient amount of the organic metal source gas required for forming the semiconductor film is simultaneously and simultaneously distributed to the reaction tube in a sufficient amount for each of the organic metal source gases for forming each semiconductor film. As a result, a semiconductor film having a multilayer structure in which the composition change at the interface between the layers was sharp was able to be formed.

[Brief description of the drawings]

FIG. 1 is a schematic view of an MOCVD apparatus having a plurality of organic metal source gas supply sources according to the present invention.

FIG. 2 is a schematic view of a conventional MOCVD apparatus having a plurality of organic metal source gas supply sources.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 first raw material system, 2 second raw material system, 12 carrier gas supply source, 13 reaction tube, 14 heating means, 15 susceptor, 16 substrate, 20 carrier gas dummy line, 21 vent line, 22 reactor line, 32
Source gas supply source, 41-44, 141-144 Organometallic source gas outlet pipe, 51-54, 151-154
Carrier gas supply pipe, 61-64, 161-164
Organic metal raw material gas supply source, 71 to 74, 171, 172
Switching means, 71a to 74a, 71b to 74b, 1
71a, 172a, 171b, 172b Valve, 81
~ 84,97,101 ~ 104,107,181 ~ 18
4, 201, 202 Mass flow controller, 120
Sub-line of carrier gas, 131 to 134, 23
1,232 carrier gas extrusion line, 301
A first junction, 302 a second junction, 401, 402,
501-504 Piezo valve

Claims (6)

[Claims] 1. An organic metal raw material gas of two or more of the same family is connected to a reaction tube in which a substrate on which metal organic chemical vapor deposition is to be performed is arranged, and is joined before being supplied to a reactor line to which a carrier gas is supplied. A metalorganic vapor phase epitaxy method comprising supplying a reaction tube in which a substrate on which metalorganic vapor phase epitaxy is performed is disposed. 2. The method according to claim 1, wherein the two or more binary organic metal source gases are
2. The metalorganic vapor phase epitaxy method according to claim 1, wherein the organic metal source gas is a group III element. 3. The method according to claim 1, wherein each of the two or more organometallic raw material gases comprises:
2. The metalorganic vapor phase epitaxy method according to claim 1, wherein the organic metal source gas is a group II element. 4. A supply source of at least two organic metal source gases of the same family is provided, and a substrate on which the source gas from each of the organic metal source gases is subjected to metal organic chemical vapor deposition is arranged. A metal-organic vapor phase epitaxy apparatus, wherein a merging section is provided before the carrier gas is supplied to a reactor line connected to the reaction tube. 5. The organometallic vapor phase epitaxy apparatus according to claim 4, wherein each of said at least two organic metal source gases of the same family is an organic metal source gas of a group III element. 6. The organometallic vapor phase epitaxy apparatus according to claim 4, wherein each of said at least two organic metal source gases of the same family is an organic metal source gas of a Group II element.