JP2001302389A - Vapor phase growing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a growing method by which an epitaxial film such as InGaAs layer and InP layer, being markedly different in composition, can be laminated and grown without lowering steepness at the interface. SOLUTION: The vapor phase growing method comprises arranging a substrate on a substrate supporting stand provided at the inside of a reaction furnace, supplying a source gas for growing a desired thin film, and successively depositing/growing at least two kinds of thin layers, being different in the composition, on the surface of the substrate. The vapor phase growing method includes the process of introducing a first source gas into the reaction furnace and growing a first layer on the substrate, the process of introducing a second source gas and growing an intermediate layer on the first layer in order to prevent vaporization of a volatile element constituting the first layer while discharging the first source gas, the growth interruption process of introducing a purge gas which contains one or two kinds of gases selected from the source gases for growing the second layer and which is capable of thermally etching the intermediate layer and discharging the first and second gases while etching the intermediate layer and the process of introducing a third source gas and growing a second layer lattice-aligning to the first layer and having a composition different from that of the first layer, on the intermediate layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor phase growth method for stacking and growing epitaxial films of compound semiconductors having different compositions, and more particularly to a technique suitable for application to a metal organic vapor phase growth method.

[0002]

2. Description of the Related Art In recent years, a technique of growing an epitaxial film on a compound semiconductor substrate such as gallium arsenide (GaAs) or indium phosphide (InP) has attracted much attention. According to recent technologies, indium gallium arsenide (InGaAs), indium gallium phosphide (InGaP), aluminum gallium arsenide (AlGaAs), indium aluminum arsenide (In) are used as epitaxial films.
AlAs), indium gallium arsenide phosphorus (InGaAs)
A so-called mixed crystal layer such as sP) can also be grown.

One of the effective methods for growing these epitaxial films is metal organic chemical vapor deposition (MOCVD).
There is. Here, the metal organic chemical vapor deposition method will be briefly described with reference to FIG.

FIG. 5 is a schematic view of an apparatus capable of realizing a metal organic chemical vapor deposition method, wherein reference numeral 1 denotes a reaction tube, 2a denotes an inlet for an organic metal material (TMI, TMG, etc.), and 2b denotes a 5B group. inlet of the hydrogenation gas (PH _3, AsH _3, etc.), 3 is a heater mainly to heat the substrate, the substrate for 4 to grow an epitaxial film, 5 is a substrate holder, 6 is an exhaust port.

[0005] Trimethylindium (TMI), trimethylgallium (TMG), triethylgallium (TE
G) and so-called organic metal such as trimethylaluminum (TMA) and arsine (AsH ₃ ) or phosphine (PH ₃ ) gas as raw material gas, and the substrate 4 through the inlet 2 together with hydrogen (H ₂ ) as a carrier gas. When the raw material gas is supplied into the placed reaction tube 1, the raw material gas is decomposed on the upstream side U of the substrate 4,
A group (3B) element and a group 15 (5B) element react to grow a thin film. In addition, as a raw material gas, an organic metal such as trimethyl arsenic or tert-butyl phosphine can be used instead of a gas such as arsine or phosphine.

For example, a description will be given according to a supply gas switching sequence shown in FIG.
If I, TMG and AsH ₃ are introduced into the reaction tube as raw materials, they are decomposed on the upstream side U of the substrate and reacted on the substrate 4 to grow an InGaAs layer (first layer). Then S1
In step 2, if the supply of TMG and AsH ₃ is stopped and the supply of PH ₃ is started, TMI and PH ₃ are decomposed at the upstream side U of the substrate and reacted on the InGaAs layer to react with the InP layer (second layer).
Can grow.

At this time, the source gas for forming the InP layer (second layer) is a source gas for the InGaAs layer (first layer), which is unnecessary for forming the InP layer, ie, TMG.
If InH ₃ or AsH ₃ is mixed, the crystallinity of the InP layer deteriorates.
In order to sufficiently exhaust the remaining TMG and AsH ₃ by the carrier gas H ₂ , the crystal growth is interrupted by inserting a growth interrupting process between the first layer growing process and the second layer growing process. I am trying to do it.

However, during the growth interruption process, In
An epitaxial film containing a Group 5B element such as P (first
If the layer is left as it is, there is a problem that the group 5B element (P) evaporates from the layer surface due to high vapor pressure. Therefore, in the growth interruption process, a gas containing a group 5B element (AsH ₃ , P
A method has been proposed in which H ₃ ) is continuously supplied as a purge gas for a predetermined period of time, and then is switched to the source gas of the second layer.

For example, Japanese Unexamined Patent Publication No. 9-213641 (a method of forming a steep heterointerface by metalorganic vapor phase epitaxy) is disclosed in Oki Electric Industry Co., Ltd.
In the case of growing an nP layer, after growing an InGaAs layer, AsH ₃ is supplied as a purge gas for a predetermined time and the InGaAs is grown.
The first layer source gas is exhausted while preventing As from evaporating from the GaAs layer surface, and then the InP source gas T
Technical supplies MI and PH ₃ are disclosed. This technique uses a Group 5B element (As, P) contained in the first layer.
Is also included in the second layer, for example, when the first layer is InGaP
In the case where the second layer is InP, P
By supplying H ₃ , P can be prevented from evaporating from the first layer due to the partial pressure and TMG can be exhausted, so that there is an advantage that PH ₃ can be used as a source gas for the second layer as it is. .

[0010]

However, in the above prior art, the first layer is an InGaAs layer and the second layer is an InP layer.
It has been found that the following problem occurs when epitaxial films having greatly different compositions are stacked and grown as in the case of a layer.

For example, on an InGaAs layer (first layer),
Consider a case where InP (second layer) is grown. According to the technique described above, InGaAs is used in the growth interruption process.
In order to prevent As from evaporating from the layer surface, AsH ₃ is supplied, and thereafter, switching from AsH ₃ to TMI and PH ₃ is performed. In this case, in the growth interruption process, A
Since sH ₃ is supplied, evaporation of As from the first layer can be prevented. However, when the supply of TMI and PH ₃ is started, AsH ₃ still remains, so that TMI, PH ₃ and AsH ₃ are present in the reaction tube in a mixed state. As a result, the crystallinity of the InP layer (second layer) formed from these gases decreases, and the steepness of the interface between the first and second layers also deteriorates. This effect tends to increase as the growth time of the first layer increases, and depends on the shape of the reaction tube, the gas supply conditions, the composition of the growing layer, etc., but the gas before and after switching is mixed in the order of several seconds to tens of minutes. It has been confirmed by the inventor's experiment that the above-mentioned state continues.

Conversely, an InGaAs layer (first layer) is grown.
In the growth interruption process _ThreeDo you only supply
Et al., TMI and PH_ThreeTo supply InP (second layer).
When it is formed, TMG unnecessary for forming the InP layer is formed.
AsH_ThreeIs exhausted completely and mixes with the source gas of the InP layer.
But the InG in the growth interruption process
As evaporates from the surface of the aAs layer, or As in the InGaAs layer.
As and PH_ThreeOf InGaAs is replaced by InGaAs.
The quality of the layer is reduced.

Therefore, the present invention solves the above-mentioned problems, and
It is an object of the present invention to provide a method capable of stacking and growing epitaxial films having greatly different compositions, such as an nGaAs layer and an InP layer, without impairing the steepness of the interface.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and is intended to dispose a semiconductor substrate on a substrate holder provided in a reaction furnace and grow a desired thin film. In a vapor phase growth method in which at least two thin films having different compositions are sequentially laminated and grown on the surface of the semiconductor substrate, a first raw material gas is introduced into the reaction furnace. A process of growing a first layer on a substrate and an intermediate step of introducing a second source gas and exhausting the first source gas to prevent evaporation of volatile elements constituting the first layer. A process of growing a layer on the first layer, and introducing one or two kinds of source gases for growing the second layer, the purge gas being capable of thermally etching the intermediate layer; Do not etch the intermediate layer A growth interruption process to evacuate the al first and second raw material gas, by introducing a third source gas,
Lattice-matched to the first layer on the intermediate layer;
And a process of growing a second layer having a composition different from that of the layer.

By growing the intermediate layer on the first layer, it is possible to prevent the constituent elements of the first layer from evaporating in the growth interruption process and to prevent the surface state of the first layer from deteriorating. Since the first source gas for the growth can be sufficiently exhausted so as not to be mixed with the third source gas for growing the second layer, even when the thin films having different compositions are stacked and grown, the crystal having excellent steepness can be obtained. An interface is formed, and high-quality crystals can be obtained.

It is preferable that the intermediate layer is grown so as to remain after the thermal etching in the growth interruption process at a thickness that does not affect the quality of the whole crystal. That is, the time for performing the growth interruption process is set based on the time for sufficiently exhausting the source gas of the first layer,
It is desirable to form the intermediate layer to such a thickness that the entire intermediate layer is etched by thermal etching during the growth interruption process so that the surface of the first layer is not exposed. As a result, the entire intermediate layer is etched, the surface of the first layer is exposed, and the constituent elements (group 5B) of the first layer evaporate to form the first layer.
Deterioration of the surface state of the layer can be prevented, and the intermediate layer does not lower the crystal quality.

Further, it is preferable that the above-mentioned process is performed in a metal organic chemical vapor deposition method.

At least one of the epitaxial films may be a compound semiconductor mixed crystal. Further, the semiconductor substrate may be a compound semiconductor.

[0019] In particular, the semiconductor substrate and the epitaxial film are formed of a group IIIB element and a group 5B element.
By using a group II-V compound semiconductor, the effect of the present invention is remarkably exhibited.

Further, when the semiconductor substrate is InP and the epitaxial films are all III-V compound semiconductors lattice-matched to InP within 0.5%, it is possible to obtain crystals of particularly excellent quality. it can.

The intermediate layer is a group III-V compound semiconductor, and the second layer contains a group 5B element contained in the intermediate layer.

Thus, by supplying a gas containing a Group 5B element contained in the intermediate layer and the second layer in the growth interruption process, it is possible to prevent the Group 5B element from evaporating from the surface of the intermediate layer. Impurity gas (first and second source gases) can be prevented from being mixed into the third source gas. Further, although the intermediate layer is removed by thermal etching in the growth interruption process, it is difficult to completely remove the intermediate layer. Therefore, in order to improve the quality of the whole crystal, the remaining intermediate layer has good crystallinity. It is desirable. Therefore, it is important to prevent the Group 5B element from evaporating from the surface of the intermediate layer.

Further, it is desirable that the thickness of the remaining intermediate layer is smaller because the influence on the quality of the whole crystal is reduced, and when the crystallinity of the intermediate layer is good and the thickness is sufficiently small,
Experiments have shown that the presence of the intermediate layer does not affect the overall quality of the crystal. Specifically, if the thickness of the intermediate layer after thermal etching is 1 to 20 nm, the quality of the entire crystal is not affected when the thickness of the entire crystal is 0.1 μm or more.

Further, the III-V group compound semiconductor is
For example, as in InGaP, InGaAs, and InGaAsP, at least three elements out of In and Ga as Group 3B elements and As and P as Group 5B elements can be included. The present invention can be applied when growing epitaxial films having such a large difference in composition.

In the growth interruption process, AsH ₃ when the intermediate layer contains As, PH ₃ when the intermediate layer contains P, and AsH ₃ and PH when the intermediate layer contains As and P. The mixed gas of No. ₃ was introduced as a purge gas. Thus, the gas supplied in the growth interruption process can be supplied as it is as the third source gas, so that the operation can be performed efficiently.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

An InGaAs layer (first layer) 12 and an InP layer (second layer) 1 are formed on an InP substrate 13 as shown in FIG.
No. 1 was laminated and epitaxially grown to produce a semiconductor crystal. Note that InGaAs and InP are crystals that are lattice-matched within 0.1%.

As a raw material, trimethylindium (TM
I), trimethylgallium (TMG), arsine (As
H ₃ ) and phosphine (PH ₃ ) were used. The growth temperature was 650 ° C., the total gas flow rate was 50,000 sccm, and the growth pressure was 50 torr.

Here, [sccm] is 0 ° C.
The flow rate for one minute under one atmosphere is expressed in cc and refers to a standard volume.

FIG. 1 shows a sequence for switching the supply of the source gas in the crystal growth of the present embodiment. In this sequence, [ON] indicates that the source gas is being supplied into the reaction tube, and [OFF] indicates that the supply of the source gas has been stopped. FIG. 7 is a schematic view showing a crystal growth process of the present embodiment.

First, in process P1, AsH ₃ is 500 sccm, TMI is 2.5 sccm and TMG
Is supplied at 2.5 sccm for 60 minutes, and the InP substrate 13 is supplied.
An InGaAs layer (first layer) 12 was grown thereon by 2.5 μm (FIG. 7A). Next, in process P2, A
Stop supply of sH ₃ and TMG and adjust PH ₃ to 600 scc
m and TMI were supplied at 6.0 sccm for 1 minute to grow an InP layer 14 as an intermediate layer to a thickness of 15 nm (FIG. 7).
(B)).

Next, in process P3, 10min at 600sccm only PH ₃ by stopping the supply of TMI
The supplied AsH ₃ and TMG remaining in the reaction tube were replaced with PH ₃ (FIG. 7 (c)). At this time, the InP intermediate layer 14 formed in the process P2 forms InGaAs.
The evaporation of As from the layer 13 is prevented. In the process P3, AsH ₃ and TMG are replaced with PH ₃ , and the portion 14b in FIG. 7C is thermally etched. At the end of the process P3, the InP intermediate layer 14a
Had a thickness of 5 nm.

[0033] Next, in the process P4, to start the supply of TMI while continuing the supply of PH _3, PH ₃ 60
By supplying 0 sccm and TMI at 6.0 sccm for 60 minutes, the InP layer (second layer) 11 was grown to 1.5 μm (FIG. 7D).

When the obtained crystal was observed with an optical microscope, it was a good crystal and no defect was observed.
Further, from the analysis result by SIMS shown in FIG.
The amount of As mixed in the layer 11 is 2 to 10 × 10 ^{19 at.}
ms / cc, the mixing amount of Ga is 1 to 10 × 10 ^{18 at}
ms / cc.

For comparison, when the time of the growth interruption process in the process P3 was set to 1 minute, the InP layer 11 was formed.
Cross hatch-like defects occurred on the surface. This is because the remaining TMG, AsH ₃ and P
It is considered that the cause was that TMG and AsH ₃ were mixed in the source gas supplied in the process P4 because H ₃ was not sufficiently substituted.

For further comparison, the InP intermediate layer 14 was grown to a thickness of 100 nm in the process P2 and the time in the process P3 was set to 10 minutes.
The crystallinity of the P layer 11 deteriorated, and cross-hatched defects were observed. This is considered to be because the InP intermediate layer 14a having poor crystallinity was not removed by thermal etching to such an extent that its influence could be ignored.

From the above, although the conditions vary depending on the layer to be grown, the gas supply amount, the vapor phase growth apparatus, etc., the growth interruption time (process P3) Is set, and the InP intermediate layer 14 is not completely etched by the thermal etching performed in the growth interruption process, and has such a thickness that the crystallinity of the whole crystal is not affected.
It is understood that it is necessary to optimize such as by growing.

Next, for comparison, the crystal shown in FIG. 6 was grown and its crystallinity was evaluated in accordance with the conventional material gas supply switching sequence shown in FIGS.

FIG. 2 shows a sequence when the growth interruption process is not performed. First, as in the process P1, A
By supplying sH ₃ at 500 sccm, TMI at 2.5 sccm and TMG at 2.5 sccm for 60 min, InP
An InGaAs layer was grown on the substrate 13 by 1 μm (process P11). Next, supply of AsH ₃ and TMG was stopped, PH ₃ was set to 600 sccm, and TMI was set to 6.0 sccm.
For 60 minutes to grow the InP layer 13 to 1.5 μm (process P12).

When the obtained crystal was observed with an optical microscope, the crystallinity of the InP layer 11 on the GaInAs layer 12 was deteriorated, and a defect on the cross hatch was observed on the surface of the InP layer 11. Further, from the analysis result by SIMS shown in FIG. 9, the mixing amount of As in the InP layer 11 is 5 × 10 ¹⁹ to 8 × 10 ²⁰ atoms / cc, and the mixing amount of Ga is 2 × 10 ¹⁸ to 2 × 10 ¹⁹ atoms. / Cc, and the mixing amount is increased by one digit or more as compared with the crystal of the present embodiment.

FIG. 3 shows that AsH during the growth interruption process._ThreeTo
This is the sequence in the case of supplying. First, AsH_Three5
00 sccm, TMI 2.5 sccm and TMG
Supply at 2.5 sccm for 60 min on InP substrate 13
A 1 μm InGaAs layer was grown on the substrate (process P2).
1). Next, the supply of TMG is stopped and AsH_ThreeOnly
It was supplied at 500 sccm for 20 minutes (process P2
2). Next, AsH _ThreeStop supply of PH_ThreeWhen
Start supply of TMI, PH_Three600 sccm, TM
I is supplied at 6.0 sccm for 60 minutes, and the InP layer 13 is supplied.
Was grown 1.5 μm (process P23).

Also in this case, cross-hatched defects were observed on the surface of the InP layer 11. This is because if the group 5B element As contained in the first layer is supplied in the growth interruption process (process P22), the evaporation of As from the surface of the first layer can be prevented, but the supplied source gases are MTI and PH. _Three
Since the AsH ₃ remains when switching to
This is because As is mixed into the nP layer 11.

FIG. 4 shows a sequence when PH ₃ is supplied during the growth interruption process. First, 50 AsH ₃
By supplying 0 sccm, TMI of 2.5 sccm and TMG of 2.5 sccm for 60 minutes, an InGaAs layer was grown to 1 μm on the InP substrate 13 (process P3).
1). Next, the supply of TMG was stopped, and only PH ₃ was changed to 6
It was supplied at 00 sccm for 20 minutes (process P3
2). Next, PH ₃ starts the supply of TMI while supplying, the PH ₃ 600 sccm, the TMI 6.0Sccm
And the InP layer 13 was grown 1.5 μm by supplying for 60 minutes (process P33).

In this case, although the gas was sufficiently replaced in the growth interruption process (process P32), no cross hatch-like defect was generated. However, during the growth interruption process, As evaporated from the InGaAs layer or P , The surface state of the InGaAs layer deteriorated.

From these results, it was proved that according to the crystal growth method of the present invention, it is possible to grow an InP layer on an InGaAs layer with good interface steepness.

Although the invention made by the inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments.

For example, in the present embodiment, the second layer (I
nP) and a crystal (InP) lattice-matched with
As described above, since the intermediate layer is removed by thermal etching to a thickness that does not affect the quality of the whole crystal, another composition such as GaP can be used as the intermediate layer. In that case, the combination of the thickness of the intermediate layer and the optimum value of the growth interruption time is different from the case where the intermediate layer is the InP layer. Specifically, the time for performing the growth interruption process is set based on the time for sufficiently exhausting the source gas of the first layer, and the etching amount (thickness) removed by thermal etching during the growth interruption process is determined. The thickness (time) for forming the intermediate layer may be determined based on the thickness. Of course, the thickness of the intermediate layer after the etching is preferably reduced to such an extent that the crystallinity of the whole crystal is not affected.

Table 1 shows combinations of materials to which the present invention can be applied. It has been confirmed that good quality crystals can be obtained with at least the combinations of the materials listed in Table 1. The combination of materials is not limited to the examples shown in Table 1, and the intermediate layer is formed so as to include at least one of the elements belonging to Group 5B which is a constituent element of the second layer. In the interruption process, the gas containing the Group 5B element may be supplied as the purge gas.

[0049]

[Table 1]

In this embodiment, the case where two types of epitaxial films having different compositions are grown on the substrate has been described. However, the present invention further provides a third layer, a fourth layer,.
It is also applicable to a method of growing a crystal having a multilayer structure. At this time, the intermediate layer formed between the second layer and the third layer, and the intermediate layer formed between the third layer and the fourth layer are each composed of a 5B layer included in the layer grown on the intermediate layer. The growth interruption process may be performed by including at least one group element and supplying a gas including the group 5B element as a purge gas.

[0051]

According to the invention disclosed in the present application,
By growing the intermediate layer on the first layer, it is possible to prevent the constituent elements of the first layer from evaporating in the growth interruption process and to prevent the surface state of the first layer from deteriorating. Since the exhaust gas can be sufficiently exhausted so as not to be mixed into the two-layer source gas, a crystal interface having excellent steepness is formed, and a high-quality crystal can be obtained. In particular, the InGaAs layer and In
A remarkable effect can be obtained by applying the present invention to a case where epitaxial films having greatly different compositions such as a P layer are stacked and grown.

[Brief description of the drawings]

FIG. 1 is a supply gas switching sequence diagram in crystal growth of the present invention.

FIG. 2 is a supply gas switching sequence diagram in crystal growth when a growth interruption process is not performed.

FIG. 3 is a supply gas switching sequence diagram in crystal growth when AsH ₃ is supplied in a growth interruption process.

FIG. 4 is a supply gas switching sequence diagram in crystal growth when PH ₃ is supplied in a growth interruption process.

FIG. 5 is a schematic diagram of a metal organic chemical vapor deposition apparatus.

FIG. 6 is a schematic view of a crystal grown in the present embodiment.

FIG. 7 is a schematic view illustrating a crystal growth process of the present embodiment.

8 is a SIMS measurement result chart of the crystal grown according to the crystal growth sequence of FIG.

FIG. 9 is a SIMS measurement result chart of the crystal grown according to the crystal growth sequence of FIG. 2;

[Explanation of symbols]

 Reference Signs List 1 reaction tube 2a inlet for organometallic raw material 2b inlet for group 5B hydrogenated gas 3 heater 4 substrate 5 substrate holder 6 exhaust outlet U upstream side L downstream side 11 InP layer (second layer) 12 InGaAs layer (first layer) 13 InP substrate 14 InP intermediate layer 14a InP layer (remaining portion) 14b InP layer (etching portion)

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Mitsuhiro Kamoto 3-17-35 Niisominami, Toda City, Saitama Prefecture Nikko Materials Isohara Plant Toda branch room F term (reference) 4G077 AA03 AB07 BE41 BE47 DB08 ED06 HA06 TA04 5F041 AA31 AA40 CA34 CA39 CA64 CA65 CA74 CA77 5F045 AA04 AB12 AB17 AC08 AC09 AE23 AF04 BB05 EB14 5F073 CA07 CA17 CB02 DA05 DA35

Claims (10)

[Claims] 1. A semiconductor substrate is placed on a substrate holding table provided in a reaction furnace, and a source gas necessary for growing a desired thin film is supplied. A method of introducing a first source gas into the reaction furnace to grow a first layer on the substrate; and introducing a second source gas into the reaction furnace. A process of growing an intermediate layer on the first layer for preventing the volatile elements constituting the first layer from evaporating while exhausting the first source gas; 1 or 2 of source gas
A growth interruption process of introducing a purge gas capable of thermally etching the intermediate layer and exhausting the first and second source gases while etching the intermediate layer; Introducing, and growing a second layer having a composition different from that of the first layer lattice-matched to the first layer on the intermediate layer. 2. The vapor phase growth method according to claim 1, wherein the intermediate layer remains at a thickness that does not affect the quality of the whole crystal after the thermal etching in the growth interruption process. 3. The vapor phase growth method according to claim 1, wherein the epitaxial film is grown by a metal organic chemical vapor deposition method. 4. The semiconductor device according to claim 3, wherein at least one of said epitaxial films is a compound semiconductor mixed crystal.
3. The vapor phase growth method according to item 1. 5. The vapor deposition method according to claim 4, wherein said semiconductor substrate is a compound semiconductor. 6. The semiconductor substrate and the epitaxial film are formed of a Group 13 (3B) element and a Group 15 (5B).
The method according to claim 5, wherein the method is a group III-V compound semiconductor comprising an element. 7. The semiconductor device according to claim 6, wherein the semiconductor substrate is InP, and each of the epitaxial films is a group III-V compound semiconductor lattice-matched to InP within 0.5%. Phase growth method. 8. The semiconductor device according to claim 6, wherein the intermediate layer is a III-V compound semiconductor, and the second layer includes a Group 15 (5B) element contained in the intermediate layer. 8. The vapor phase growth method according to 7. 9. The first and second layers are formed of In, G,
9. The vapor phase growth method according to claim 6, comprising at least three elements of a, As and P. 10. In the growth interruption process, when the intermediate layer contains As, AsH ₃ is used, and when the intermediate layer contains P,
The PH ₃ if it contains, according case where the intermediate layer containing As and P from claim 6, characterized in that a mixed gas of AsH ₃ and PH ₃ as a purge gas to one of claims 9 Vapor phase growth method.