JPH11145061A - Vapor growth method for group iii-v compound semiconductor, and light emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen point defects, etc., caused by oxygen atoms, by supplying group V material, Si material, and group Ill material onto a crystal substrate so as to execute the crystal growth of a group III-V compound semiconductor crystal layer, after supplying Si material and group III material onto the crystal substrate. SOLUTION: In the course before start of crystal growth, the first process of supplying material compounds including group V onto a crystal substrate, and the second process of supplying group V material onto the crystal substrate are interrupted. Then, after supply of Si material and group III material onto the crystal substrate, group V material and group III material are supplied onto the crystal substrate, thus the crystal growth of a group III-V compound semiconductor crystal layer is executed. As a result, a Si-doped group III-V compound semiconductor crystal can be grown on the crystal substrate where the group III-V compound semiconductor crystal layer is made on the surface. To be concrete, crystal growth is executed after performing the switching of gas in sequence on the Si-doped GaAs substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a semiconductor laser, L
The present invention relates to a vapor phase growth method of a III-V compound semiconductor such as ED and HEMT, and a light emitting device.

[0002]

2. Description of the Related Art Metalorganic vapor phase epitaxy (MOCVD), molecular beam epitaxy (MBE), etc., are excellent in mass productivity and can grow ultra-thin film crystals. It is the most promising in the future. These typical n-type group III-V compound semiconductor crystal growth methods employ a method in which the temperature of a crystal substrate having a group III-V compound semiconductor crystal layer formed thereon is raised and lowered.
A group V element is supplied onto the crystal surface to prevent arsenic, which is a group element, from thermally desorbing from the crystal surface.
A group I element, a group V element, and Si are simultaneously supplied on the crystal surface to perform crystal growth of a Si-added n-type III-V compound semiconductor.

[0003] Specifically, III in the MOCVD method
An example of a method for vapor-phase growth of a -V compound semiconductor will be described below.

On a Si-doped GaAs substrate, a Si-doped Ga
When growing an As crystal layer, triethyl gallium (TEGa) or trimethyl gallium (TMGa) as a group III material and arsine (AsH ₃ ) as a group V material are used.
And silane (SiH ₄ ) or disilane (S
i ₂ H ₆₎ using a, in heating and cooling supplies arsine purpose of suppressing escape As, then TEGa or TMGa,
By supplying AsH ₃ , SiH _4, Si ₂ H ₆ or the like, the crystal growth of the Si-doped GaAs crystal layer is performed.

An oxide film is formed on the surface of the III-V compound semiconductor crystal layer. If the oxide film is not removed before the crystal growth, the crystal grown on the substrate has a bad influence. Various measures have been taken. In JP-A-1-301584, active hydrogen is irradiated on a substrate surface in a high vacuum to remove a surface oxide film and grow the substrate. In JP-A-3-227531, the substrate is grown by etching the substrate surface with a reactive gas to remove the surface oxide film. In JP-A-7-94411, a surface oxide is removed by thermal cleaning to provide a group III stabilized surface, and crystal growth is performed.

[0006]

In the above conventional method,
In the case where Si or Al is contained in the outermost surface layer of the crystal substrate having the III-V compound semiconductor crystal layer formed on the surface, the outermost surface is oxidized by thermal cleaning as disclosed in JP-A-7-94411. After removing the film,
Although there is no damage on the substrate surface, it is difficult to remove the bond between Si and oxygen (Si-O) and the bond between Al and oxygen (Al-O) on the outermost surface, so that the oxide film on the uppermost surface of the substrate cannot be completely removed.

Therefore, as shown in FIG. 7 (b), when the substrate surface is exposed to oxygen atoms bonded to Si or Al, the As group Si elements and As group Si elements and the above group III element Ga atoms are exposed. At the same time on a crystal substrate, and III-
When performing crystal growth of the group V compound semiconductor crystal layer, As and Ga are hardly bonded to oxygen, and even if bonded to oxygen, the bonding energy is small, so that they are immediately dissociated. Si is easily bonded to oxygen, but the group V element A
Since s, Si, and Ga, which is the group III element, are simultaneously supplied onto the crystal substrate, the probability of bonding between Si and oxygen is reduced. Therefore, in the vicinity of the oxygen atom, As enters the atomic position of Ga, or there is no atom at the atomic position of Ga, and a point defect due to the oxygen atom easily occurs. If crystal growth is performed in this state, dislocation defects due to point defects naturally occur as shown in FIG.

In the case where Si or Al is contained in the outermost layer of the III-V compound semiconductor crystal layer, Japanese Patent Application Laid-Open Nos. 1-301584 and 3-22
When the outermost oxide film is removed using active hydrogen or a reactive gas as disclosed in Japanese Patent No. 7531, even if the oxide film on the outermost surface can be completely removed, damage to the substrate surface and carrier carriers on the substrate surface may occur. With the consequence of deficiency.

As a result, dislocation defects are caused by damage to the substrate surface and oxygen at the interface between the substrate and the crystal layer. When the dislocation defect is present, the I-crystal formed on the crystal substrate on which the III-V compound semiconductor crystal layer is formed is formed.
Dislocation defects occur throughout the II-V compound semiconductor crystal layer. As a result, an impurity having a large diffusion coefficient such as zinc, beryllium, magnesium, and selenium is added.
Diffusion occurs due to dislocation defects in the added impurities in the group V compound semiconductor crystal layer. Along with the dislocation defect and the diffusion of the additional impurity, the III-V compound semiconductor light emitting device
This causes a problem such as element deterioration during energization, and further lowers the yield.

According to the present invention, as a result of studying the above problems, it has been found that a high quality crystal growth film capable of forming a high quality crystal growth film with reduced dislocation defects caused by damage to the substrate surface and oxygen at the interface between the substrate and the crystal layer can be formed. Invented is a method for vapor-phase growth of a group III compound semiconductor.

[0011]

According to the present invention, there is provided a vapor phase for growing a group III-V compound semiconductor crystal doped with Si on a crystal substrate having a group III-V compound semiconductor crystal layer formed thereon. In the growth method, before the start of crystal growth, a first step; a second step of supplying a group V source material onto the crystal substrate; interrupting the supply of the group V source material onto the crystal substrate; After the raw material and the group III raw material are supplied on the crystal substrate, the group V raw material, the Si raw material, and the group III raw material are supplied on the crystal substrate, and the crystal growth of the III-V compound semiconductor crystal layer is performed. It is another object of the present invention to provide a method for vapor-phase growing a group III-V compound semiconductor.

Further, the present invention provides a vapor phase growth method for growing a group III-V compound semiconductor crystal to which Si is added on a crystal substrate having a group III-V compound semiconductor crystal layer formed thereon. In the process before the start of crystal growth, a first step; a second step of supplying a group V source onto the crystal substrate; interrupting the supply of a group V source onto the crystal substrate;
A third step of supplying a Si raw material and a Group III raw material onto the crystal substrate; stopping supplying the Si raw material and the Group III raw material onto the crystal substrate, and supplying a Group V raw material onto the crystal substrate. After that, a group V material, a Si material and a group III material are supplied onto the crystal substrate, and a crystal growth of a group III-V compound semiconductor crystal layer is performed. It provides a growth method.

More specifically, after gas is switched on a Si-doped GaAs substrate in the sequence shown in FIGS. 1 and 2, crystal growth is performed.

Further, according to the present invention, the n-type impurity
In a III-V compound semiconductor light emitting device using
An object of the present invention is to provide a III-V compound semiconductor light emitting device manufactured using the method of vapor-phase growing a III-V compound semiconductor.

[0015]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a Si-added III-V
Prior to the crystal growth of the group III compound semiconductor crystal, in the first step, oxygen combined with As and oxygen combined with Ga are decomposed and separated while supplying a group V element such as arsenic during the temperature rise of the substrate, As shown in FIG. 6B, the surface of the substrate is almost covered with As atoms.
Since the bond between oxygen and oxygen hardly breaks down at this point,
Oxygen atoms bonded to Si or Al are exposed to the surface of the substrate.

In the next second step, the supply of the group V raw material onto the crystal substrate is interrupted, and the Si raw material and the group III raw material are supplied onto the crystal substrate.
Ga couples with As as shown in FIG. Si combines with oxygen and enters the atomic position of Ga. As a result, only Ga and Si remain on the substrate surface.

In the state where only Ga and Si are exposed to the substrate surface, the point defects at the substrate interface are reduced, so that the group V raw material, the Si raw material and the group III raw material are simultaneously supplied onto the crystal substrate. As shown in FIG. 6D, a high-quality group III-V compound semiconductor crystal with reduced dislocation defects can be grown. Further, since the substrate surface treatment such as etching is not performed, no damage is given to the substrate surface, so that a high-quality III that eliminates dislocation defects caused by damage to the substrate surface is obtained.
-Group V compound semiconductor crystal can be grown.

Hereinafter, embodiments of the present invention will be described in detail. (Embodiment 1) In this embodiment, a method of growing a Si-doped GaAs crystal film on a Si-doped GaAs substrate will be described.

Si-doped GaAs on a Si-doped GaAs substrate
Trimethyl gallium (TMGa) for growing thin film
And arsine (AsH ₃ ) diluted to 10% with hydrogen (H ₂ )
And disilane (Si ₂ H ₆ ) diluted to 100 ppm with H ₂
Was used as a raw material. The apparatus used was a vapor phase growth apparatus of a reduced-pressure horizontal high-frequency heating furnace, and the furnace pressure was set to 76 Torr. The crystal growth was performed according to the sequence shown in FIG.

After starting the temperature increase of the Si-doped n-type GaAs substrate,
Start supplying AsH ₃ onto the Si-doped n-type GaAs substrate,
After the substrate temperature rises to 750 ° C.,
Cool down to 70 ° C. Thereafter, the supply of AsH _{3 to} the substrate is temporarily stopped, and TMGa and Si ₂ H ₆ are added to the Si-added n-type Ga.
It is supplied on an As substrate. Thereafter, the ratio of the supply amount of the raw material compound containing the group III element (TMGa) to the supply amount of the raw material compound containing the group V element (AsH ₃ ) is set to 120, and AsH ₃ ,
At the same time, TMGa and Si ₂ H ₆ are supplied onto the Si-doped n-type GaAs substrate, and the substrate temperature is raised to 750 ° C.
Crystal growth of a Si-doped GaAs thin film was performed. The growth time is 90 min and the Si-added n-type GaAs having a thickness of 2 μm
An s thin film was obtained.

For comparison, as shown in the sequence of FIG. 3, supply of AsH ₃ onto a Si-added n-type GaAs substrate is started, and after the substrate temperature is stabilized at 750 ° C., AsH ₃ and TMG
a, supplying Si ₂ H ₆ onto a Si-doped n-type GaAs substrate;
A conventional method for crystal growth of a Si-doped GaAs thin film is used.
A Si-doped GaAs thin film having a thickness of μm was also prepared.

[0022] Although the dislocation defect density after the crystal growth of the resulting two growth layers were measured, in the conventional method 1000 / cm ²
However, by using the crystal growth method of the present invention,
It can be dramatically reduced to 300 / cm ² .

Further, as a result of impurity analysis of the two grown layers obtained by using a secondary ion mass spectrometer (SIMS), the oxygen concentration at the interface between the Si-doped n-type GaAs substrate and the Si-doped GaAs thin film was reduced. Compared with the method, the reduction was achieved by using the crystal growth method of the present invention. From the above, it is understood that a high-quality Si-doped GaAs thin film can be manufactured by using the crystal growth method of the present invention.

In this embodiment, a method of growing a Si-doped GaAs crystal film on a Si-doped GaAs substrate is described.
Similar results can be obtained with nP or the like, or other S
i-added III-V compound semiconductor crystal film, for example, Al
GaAs, InGaAs, AlGaInP, InGa
Similar results are obtained with P, InGaAsP, and the like.

(Embodiment 2) In this embodiment, Si-added Al
A method for growing a Si-added AlGaAs crystal film on a GaAs crystal layer will be described.

On a Si-doped GaAs substrate, a Si-doped AlGaAs thin film having a thickness of 1 μm is lengthened, and once exposed to the atmosphere, a surface oxide film is removed by wet etching, and a 1 μm thick film is formed thereon. AlG with Si
An aAs thin film was grown. The raw materials used were trimethylgallium (TMGa) and trimethylaluminum (TMA).
l) and arsine (As) diluted to 10% with hydrogen (H ₂ )
Silane (Si) diluted to 100 ppm with H ₃ ) and H ₂
H ₄ ), the apparatus used was a vapor phase growth apparatus for a reduced-pressure horizontal high-frequency heating furnace, and the furnace pressure was set to 76 Torr.

The growth of the Si-doped AlGaAs crystal thin film on the Si-doped AlGaAs crystal thin film layer was performed according to the sequence shown in FIG. In the sequence of FIG. 2, as shown in Step 3, the supply of the Si source and the Group III source onto the crystal substrate is interrupted, and the step of supplying the Group V source onto the crystal substrate is performed. Supplying a raw material, a Si raw material, and a group III raw material onto the crystal substrate, and performing crystal growth of the III-V compound semiconductor crystal layer, thereby further reducing the oxygen concentration at the regrowth interface of the Si-added AlGaAs crystal thin film layer. Becomes possible. Specifically, the procedure was performed as follows.

After starting the temperature rise of the Si-doped GaAs substrate having the Si-doped AlGaAs thin film formed on the surface, AsH ₃ is added to S
The supply is started on the i-doped AlGaAs thin film, and after the substrate temperature rises to 750 ° C., the substrate temperature is lowered to 620 ° C. Then, AsH ₃ Si-added AlGaAs
Suspending the supply on the thin film, TMGa, TMAl, S
iH ₄ is supplied on the Si-doped AlGaAs thin film. Thereafter, Si-added AlGa of TMGa, TMAl, SiH ₄
The supply on the As thin film is temporarily stopped, and AsH ₃ is again
The temperature of the substrate is raised to 750 ° C. at the same time when the substrate is supplied onto the added AlGaAs thin film. Then, the ratio between the supply amount of the raw material compound containing the group III element (TMGa) and the supply amount of the raw material compound containing the group V element (AsH ₃ ) is set to 120, and As is obtained.
N-type Al doped with H ₃ , TMGa, TMAl and SiH ₄
The Si-added AlGaAs thin film having a thickness of 1 μm was supplied on the GaAs thin film and grown on the Si-added AlGaAs thin film.

Impurity analysis of the Si-doped AlGaAs thin film obtained by the above method of the present invention was measured by a secondary ion mass spectrometer (SIMS), and the obtained result is shown in FIG.

For comparison, a Si-added AlGaAs thin film having a thickness of 1 μm was formed on the Si-added AlGaAs thin film by using two kinds of conventional methods.

A first method is to irradiate an active hydrogen in a high vacuum on the oxide film on the surface of the Si-doped AlGaAs thin film to remove the surface oxide film and then remove the surface oxide film as shown in the sequence of FIG. AsH ₃ is started to be supplied onto the Si-doped AlGaAs thin film, and after the substrate temperature is stabilized at 750 ° C., AsH ₃ and T
A conventional method of supplying Mga, TMAl, and SiH ₄ onto a Si-doped AlGaAs thin film to grow a crystal of the Si-doped AlGaAs thin film. The second method is a Si-doped AlGaAs thin film.
After removing the surface oxide film by wet etching of the oxide film on the thin film surface, as shown in the sequence of FIG.
₃ is started to be supplied on the Si-doped AlGaAs thin film, and after the substrate temperature is stabilized at 750 ° C., AsH ₃ , TMGa, TMA
1, SiH ₄ is supplied on the Si-doped AlGaAs thin film,
This is a conventional method for performing crystal growth of a Si-doped AlGaAs thin film.

The Si-added A obtained by the above conventional method
Impurity analysis of the lGaAs thin film was performed by secondary ion mass spectrometry (S
(IMS) apparatus, and the obtained results are shown in FIGS. 8, 9, and 10, the horizontal axis represents the depth of the grown film, and the vertical axis represents the impurity concentrations of oxygen (O) and silicon (Si).

FIGS. 8, 9 and 10 show Si-doped AlGaAs.
At the s-regrowth interface, the oxygen concentration is as shown in FIG. 9 <FIG. 8 <FIG.
From the viewpoint of removing the surface oxide film, the best method is to irradiate the substrate surface with active hydrogen in a high vacuum to remove the surface oxide film. However, while the silicon concentration at the regrowth interface does not change in FIGS. 8 and 10, it decreases in FIG. 9 and carrier deficiency occurs.

Further, the dislocation defect density after crystal growth of the obtained three grown layers was measured.
Although it is 10 ⁴ / cm ² and 1 × 10 ⁴ / cm ² in the second conventional method, by using the crystal growth method of the present invention, it is ² × 10 ⁴ / cm 2.
× 10 ³ / cm ² .

As described above, by using the crystal growth method of the present invention, there is no lack of carriers at the crystal interface, the surface oxide film is removed, and a high-quality Si-doped AlGaAs thin film with reduced dislocation defects is produced. It can be seen that is possible.

In this embodiment, a method of growing a Si-doped AlGaAs crystal film on a Si-doped AlGaAs crystal layer is shown. However, other Si-doped III-V compound semiconductor crystal layers, such as GaAs, AlGaAs, InGaAs, and IGaAs
Similar results can be obtained on a crystal layer of nP, AlGaInP, InGaP, InGaAsP, or the like. Alternatively, in the case of growing another Si-added III-V compound semiconductor crystal film, for example, GaAs, AlGaAs, InGaAs, IGaAs
Similar results are obtained for nP, AlGaInP, InGaP, InGaAsP, and the like.

(Embodiment 3) In this embodiment, the Si
The optimization of the growth temperature of the added AlGaAs crystal film will be described.

After growing a Si-added AlGaAs thin film having a thickness of 1 μm on a Si-doped GaAs substrate, once exposing it to the atmosphere, removing the surface oxide film by wet etching, and then forming a 1 μm-thick film thereon. Si-added Al having
A GaAs thin film was grown. The raw materials used were trimethylgallium (TMGa) and trimethylaluminum (TMA).
l) and arsine (As) diluted to 10% with hydrogen (H ₂ )
Silane (Si) diluted to 100 ppm with H ₃ ) and H ₂
H ₄ ), the apparatus used was a vapor phase growth apparatus for a reduced-pressure horizontal high-frequency heating furnace, and the furnace pressure was set to 76 Torr.

In the crystal growth, the substrate temperature T1 (° C.) in the first step and the substrate temperature T2 in the second step in the sequence of FIG.
(° C.) at different temperatures.

After starting the temperature rise of the Si-doped GaAs substrate having the Si-doped AlGaAs thin film formed on the surface, AsH ₃ was changed to S
The supply is started on the i-doped AlGaAs thin film, and the substrate temperature is set to T
Then, after a while, the substrate temperature is changed to T2. After that, Si-added Al of AsH ₃
The supply to the GaAs thin film is temporarily stopped, and TMGa and TMA are stopped.
1, SiH ₄ is supplied on the Si-doped AlGaAs thin film. Thereafter, the supply of TMGa, TMAl, and SiH _{4 to} the Si-added AlGaAs thin film is temporarily stopped, and the supply of AsH _{3 is} stopped again.
Is supplied onto the Si-doped AlGaAs thin film, and at the same time, the substrate temperature is changed to 750 ° C. Then, the ratio of the supply amount of the raw material compound containing the group III element (TMGa) to the supply amount of the raw material compound containing the group V element (AsH ₃ ) was set to 120, and AsH ₃ , TMGa, TMAl, and SiH ₄ were added to the Si-added n-type. Si-doped AlGaAs supplied on AlGaAs thin film
Si-doped AlGaAs having a thickness of 1 μm on an s thin film
Crystal growth of the thin film was performed.

The substrate temperature T1 in the first step and the substrate temperature T2 in the second step were within a normal temperature range of a general reduced-pressure horizontal high-frequency heating furnace between 550 ° C. and 850 ° C.

The impurity analysis of the Si-doped AlGaAs thin film obtained by the above method of the present invention was measured by a secondary ion mass spectrometer (SIMS). As a result, it was found that the oxygen concentration in the Si-doped AlGaAs regrown thin film was independent of the temperature of the second step, but was dependent on the temperature of the first step. When the growth temperature in the first step is equal to or lower than 600 ° C., the oxygen concentration sharply increases.

Further, as a result of measuring the dislocation defect density after crystal growth of the obtained growth layer, the growth temperature in the second step was 650.
When the temperature is higher than or equal to ° C., the effect of reducing the dislocation defect density is not seen.

Further, even if the source gas is switched in the second and third steps while the growth temperature is not constant, if the growth temperature in the second step is 650.degree.
It has nothing to do with the oxygen concentration of the lGaAs thin film or the dislocation defect density after crystal growth.

As described above, in the crystal growth method of the present invention, as shown in FIG.
It can be seen that if the growth temperature in the second step is not less than 650C and the growth temperature in the second step is not more than 650C, it is possible to further remove the surface oxide film and produce a high-quality Si-doped AlGaAs thin film with reduced dislocation defects.

As shown in FIG. 5, if the growth temperature in the first step is not less than 600 ° C. and not more than 650 ° C., the growth temperature in the second step does not have to be lower than the growth temperature in the first step. It is understood that it is possible to remove the oxide film and produce a high-quality Si-doped AlGaAs thin film with reduced dislocation defects.

In this embodiment, a method of growing a Si-doped AlGaAs crystal film on a Si-doped AlGaAs crystal layer is described. However, other Si-doped III-V compound semiconductor crystal layers, such as GaAs, AlGaAs, InGaAs, and IGaAs
Similar results can be obtained on a crystal layer of nP, AlGaInP, InGaP, InGaAsP, or the like. Alternatively, in the case of growing another Si-added III-V compound semiconductor crystal film, for example, GaAs, AlGaAs, InGaAs, IGaAs
Similar results are obtained for nP, AlGaInP, InGaP, InGaAsP, and the like.

In this embodiment, the case of the sequence shown in FIG. 2 has been described. However, similar results can be obtained for the optimum temperature ranges of the first step and the second step of the sequence shown in FIG.

(Embodiment 4) In this embodiment, a semiconductor laser using the crystal growth method of the present invention will be described. FIG.
FIG. 1 is a sectional view of the semiconductor laser device of the present embodiment. In the first crystal growth, a Si-added n-type GaAs buffer layer 2, an n-type AlGaAs cladding layer 3, an AlGaAs active layer 4, a p-type AlGaAs first cladding layer 5, and a p-type GaAs etching are formed on a Si-added n-type GaAs substrate 1. Stop layer 6,
A p-type AlGaAs second cladding layer 7 and a p-type GaAs protection layer 8 are sequentially laminated. A stripe-shaped mesa structure is formed from above the p-type GaAs etching stop layer 6. Both sides of the mesa stripe are filled with a Si-doped n-type AlGaAs current block layer 9, an n-type GaAs current block layer 10, and a p-type GaAs planarization layer 11 in the second crystal growth. p-type GaAs protective layer 8 and p-type GaAs planarization layer 11
A p-type GaAs contact layer 12 is formed thereon. A p-side metal electrode 13 is deposited on the p-type GaAs contact layer 12, and an n-side metal electrode 14 is deposited on the Si-added n-type GaAs substrate 1.

In the above-mentioned semiconductor laser device, Si-doped n-type Ga
Each layer of the As buffer layer 2 to the p-type GaAs contact layer 12 is made of trimethylgallium (TMG) as a Ga material.
a), trimethyl aluminum (TMA)
1) Arsine (AsH ₃ ) as an As material, silane (SiH ₄ ) as a Si material as an n-type impurity, and diethyl zinc (DEZn) as a Zn material as a p-type impurity. The furnace pressure was set at 76 Torr in a furnace vapor phase growth apparatus.

First, the first crystal growth was performed by the following method. After starting the temperature increase of the Si-doped n-type GaAs substrate, AsH
₃ is started to be supplied on the Si-doped n-type GaAs substrate 1 and the substrate temperature is raised to 750 ° C.
Cool down to ° C. Thereafter, the supply of AsH _{3 to} the substrate is temporarily stopped, and TMGa and SiH ₄ are supplied onto the Si-doped n-type GaAs substrate 1. Thereafter, the ratio between the supply amount of the raw material compound containing the group III element (TMGa supply amount or the sum of the TMGa supply amount and the TMAl supply amount) and the supply amount of the raw material compound containing the group V element (AsH ₃ ) is set to 120, and AsH ₃ , TMG
a, SiH ₄ is supplied onto the Si-doped n-type GaAs substrate 1 and at the same time the substrate temperature is raised to 750 ° C.
The crystal growth of the added n-type GaAs buffer layer 2 is started.

From the Si-doped n-type GaAs buffer layer 2 to p
After the layers are sequentially stacked up to the p-type GaAs protective layer 8, the p-type GaAs etching stop layer 6 is once etched out of the vapor phase growth apparatus and etched to form a stripe-shaped mesa structure. After the etching, the substrate was again brought into the vapor phase growth apparatus, and second crystal growth was performed.

After the start of heating the regrown substrate, AsH ₃ , DE
Starting supply of Zn onto the regrown substrate, and substrate temperature of 750 ° C.
Then, the substrate temperature is lowered to 640 ° C. Thereafter, supply of AsH ₃ and DEZn to the substrate is temporarily stopped, and TMGa and SiH ₄ are supplied onto the regrown substrate.
Then, the supply amount of the raw material compound containing the group III element (TM
Ga supply amount or the sum of TMGa supply amount and TMAl supply amount) and supply amount of raw material compound containing group V element (AsH ₃ )
Of AsH ₃ , TMAl, TMGa, S
At the same time as supplying iH ₄ onto the regrowth substrate, the substrate temperature was raised to 700 ° C. to grow a crystal of the Si-added n-type AlGaAs current block layer 9.

The impurity analysis of the current block portion of the semiconductor laser device of the present invention obtained by the above method was measured by a secondary ion mass spectrometer (SIMS), and the obtained result is shown in FIG. For comparison, AsH ₃ was added with Si.
Is started on a GaAs substrate, and after the substrate temperature is stabilized at 750 ° C., AsH ₃ , TMGa, and SiH ₄ are doped with Si-added n-type G.
An impurity analysis of a current block portion of a semiconductor laser device obtained by a conventional method of supplying crystal onto an aAs substrate and starting crystal growth of a Si-doped n-type GaAs buffer layer is measured by a secondary ion mass spectrometer (SIMS). FIG. 13 shows the obtained results.
Shown in 12 and 13, the horizontal axis represents the depth of the grown film, and the vertical axis represents the impurity concentrations of zinc (Zn) and silicon (Si).

Referring to FIGS. 12 and 13, p-type AlGaAs
Although the diffusion of Zn in the s first cladding layer does not occur in FIG. 12, Zn diffuses in the n-type cladding layer and the n-type current blocking layer in FIG. 8 × 10 ¹⁷ / cm, the amount of impurity added
Not ³ This shows that the use of the crystal growth method of the present invention enables accurate control of impurity additives. Also, the dislocation defect density after crystal growth is 1 × 10 ⁵ / cm ² in the conventional method,
By using the crystal growth method of the present invention, 5 × 10 ³
/ Cm ² .

The semiconductor laser device of the present invention has a good reproducibility, and the yield is significantly improved as compared with the semiconductor laser device according to the conventional method. Also, in the reliability test at 60 ° C. and 35 mW, 500
The vehicle travels stably for 0 hour or more, which indicates that a high-quality and highly reliable semiconductor laser device can be manufactured.

Embodiment 5 In this embodiment, a light emitting diode using the crystal growth method of the present invention will be described.

FIG. 14 is a sectional view of a light emitting diode element according to the fifth embodiment. On the Si-added n-type GaAs substrate 15, S
i-doped n-type AlInP cladding layer 16, AlGaInP
Active layer 17, p-type AlInP cladding layer 18, p-type Ga
P current diffusion layers 19 are sequentially stacked. On the p-type GaP current diffusion layer 19, a p-side metal electrode 20, a Si-added n-type Ga
An n-side metal electrode 21 is deposited on the As substrate 15.

The Si-doped n-type A of the above light emitting diode element
Each layer of the lInP cladding layer 16 to the p-type GaP current spreading layer 19 is made of trimethyl gallium (TMG
a), trimethyl aluminum (TMA)
l), ln as raw material trimethylindium (TMI)
n), arsine (AsH ₃ ) as an As material, phosphine (PH ₃ ) as a P material, silane (SiH ₄ ) as a Si material as an n-type impurity, and diethyl zinc (DEZn) as a Zn material as a p-type impurity. The apparatus used was a vapor-phase growth apparatus of a reduced-pressure horizontal high-frequency heating furnace, and the furnace pressure was set to 76 Torr.

After starting the temperature increase of the Si-added n-type GaAs substrate 15, supply of AsH ₃ is started on the Si-added n-type GaAs substrate 15, and after the substrate temperature is stabilized at 770 ° C., the supply of AsH _{3 to} the substrate is stopped. TMAl, TMIn, SiH ₄ to Si
It is supplied on an additive n-type GaAs substrate. Then TMA
1, the supply of TMIn, SiH _{4 to} the substrate is temporarily stopped,
PH ₃ is supplied on a Si-doped n-type GaAs substrate. Thereafter, the supply amount of the raw material compound containing the group III element (TMGa
(The sum of the supply amount, the TMAl supply amount, and the TMIn supply amount) and the supply amount (PH ₃ ) of the raw material compound containing the group V element are set to 300.
Then, PH ₃ , TMAl, TMIn, and SiH ₄ are supplied onto the Si-added n-type GaAs substrate 15 and the Si-added n-type AlI
Crystal growth of the nP cladding layer 16 was started, and growth was performed sequentially.

The dislocation defect density of the light emitting diode of the present invention obtained by the above-described method is remarkably reduced as compared with the prior art, and as a result, the zinc in the AlGaInP active layer 17 and the Si-added n-type AlInP cladding layer 16 is reduced. Is reduced, the brightness is dramatically improved,
This indicates that a light emitting diode with high quality and high luminance can be manufactured.

(Embodiment 6) In this embodiment, Si-doped Ga
A method for growing a Si-doped GaAs crystal film on an As substrate by MBE will be described.

On a Si-doped GaAs substrate, a Si-doped GaAs
Crystal growth was performed using the MBE crystal growth method to grow the s thin film. The crystal growth was performed according to the sequence shown in FIG. The Si-added n-type GaAs substrate was introduced into the load lock chamber, and after evacuation, the substrate was heated to 250 ° C. to remove water from the substrate surface, and then transferred to the growth chamber. After the transfer, the shutter of the As cell is opened, As is supplied to the substrate surface, the substrate temperature is raised to 620 ° C, and then the substrate temperature is lowered to 480 ° C. afterwards,
The supply of As is temporarily stopped, the shutter of the Ga and Si cells is opened, and the supply of As is performed on the Si-doped n-type GaAs substrate. Then, the shutter of the As cell is opened again, and As, Ga, S
i is supplied onto the Si-doped n-type GaAs substrate, and at the same time, the substrate temperature is raised to 620 ° C.
Crystal growth of the thin film was performed. The growth time is 1.
A Si-added n-type GaAs thin film having a thickness of 5 μm was obtained.

As a result of impurity analysis of the obtained grown layer measured by a secondary ion mass spectrometer (SIMS), it was found that
By using the crystal growth method of the present invention, the oxygen concentration at the interface between the type GaAs substrate and the Si-doped GaAs thin film is larger than that of the film obtained by the growth method excluding the second step described in FIG. Had been reduced.

From the above, it can be understood that a high quality Si-doped GaAs thin film can be produced by using the crystal growth method of the present invention.

In all of the above embodiments, the switching between the supply and the stop of the raw material in the first step and the second step is performed even if the switching is performed while the growth temperature is not constant.
There is no particular relation to the oxygen concentration of the As thin film and the dislocation defect density after crystal growth. However, it is preferable to supply the raw material for crystal growth after the substrate temperature is raised to a certain temperature, since the control of the amount of added Si becomes easy. More preferably, when crystal growth is performed after the substrate temperature has reached 650 ° C. or higher, oxygen is less likely to be taken into the film, so that deterioration in crystal quality can be prevented.

[0067]

As described above, the present invention relates to III
In a vapor phase growth method for growing a group III-V compound semiconductor crystal to which Si is added on a crystal substrate having a group V compound semiconductor crystal layer formed on the surface, a first step is performed before starting crystal growth. Supplying a group V material onto the crystal substrate; stopping supplying the group V material onto the crystal substrate, and supplying a Si material and a group III material onto the crystal substrate. After performing, group V raw material, Si raw material and III
By supplying a group III raw material onto the crystal substrate and performing crystal growth of the group III-V compound semiconductor crystal layer, it is possible to reduce point defects caused by oxygen atoms and dislocation defects caused by damage to the substrate surface. Since it becomes possible to suppress the diffusion of the additional impurity that has contributed to the defect, it is possible to grow a group III-V compound semiconductor crystal having good crystallinity on a crystal substrate, and to obtain a semiconductor laser, an LED.
Greatly contribute to the improvement of the characteristics of the semiconductor light emitting device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a source gas sequence of the present invention.

FIG. 2 is a diagram showing a sequence of a source gas of the present invention.

FIG. 3 is a diagram showing a sequence of a source gas in a conventional method.

FIG. 4 is a diagram illustrating a sequence of an MBE cell according to the present invention.

FIG. 5 is a diagram showing a sequence of a source gas and a substrate temperature according to the present invention.

FIG. 6 is an atomic arrangement diagram of a group III-V compound semiconductor crystal according to the method of the present invention.

FIG. 7 is an atomic arrangement diagram of a group III-V compound semiconductor crystal according to a conventional method.

FIG. 8 is a diagram showing a result of SIMS measurement of a group III-V compound semiconductor crystal according to the method of the present invention.

FIG. 9 is a diagram showing a SIMS measurement result of a group III-V compound semiconductor crystal according to a first conventional method.

FIG. 10 is a diagram showing a result of SIMS measurement of a group III-V compound semiconductor crystal by the second conventional method.

FIG. 11 is a sectional view of a semiconductor laser device of Example 4.

FIG. 12 is a diagram illustrating a SIMS measurement result of a current block portion of a semiconductor laser device according to the method of the present invention.

FIG. 13 is a diagram showing a SIMS measurement result of a current block portion of a semiconductor laser device according to a conventional method.

FIG. 14 is a sectional view of a light emitting diode according to a fifth embodiment.

[Explanation of symbols]

 1, 15 Si-doped n-type GaAs substrate 2 Si-doped n-type GaAs buffer layer 3 n-type AlGaAs cladding layer 4 AlGaAs active layer 5 p-type AlGaAs first cladding layer 6 p-type GaAs etching stop layer 7 p-type AlGaAs second cladding layer Reference Signs List 8 p-type GaAs protective layer 9 Si-doped n-type AlGaAs current blocking layer 10 n-type GaAs current blocking layer 11 p-type GaAs planarization layer 12 p-type GaAs contact layer 13, 20 p-side metal electrode 14, 21 n-side metal electrode 16 Si-doped n-type AlInP cladding layer 17 AlGaInP active layer 18 p-type AlInP cladding layer 19 p-type GaP current diffusion layer

Claims (7)

[Claims] 1. A semiconductor comprising a group III-V compound semiconductor crystal layer on a surface of which a silicon is added.
In a vapor phase growth method for growing a group V compound semiconductor crystal, a first step; a step of supplying a raw material compound containing a group V element onto the crystal substrate; After the supply of the group V raw material onto the crystal substrate is interrupted and the supply of the Si raw material and the group III raw material onto the crystal substrate is performed, the group V raw material, the Si raw material, and the group III raw material are placed on the crystal substrate. A method for vapor-phase growing a group III-V compound semiconductor, comprising supplying and growing a group III-V compound semiconductor crystal layer. 2. A III-V compound semiconductor crystal layer, comprising a crystal substrate having a surface on which a Si-added III is formed.
In a vapor phase growth method for growing a group V compound semiconductor crystal, a first step; a second step of supplying a group V material onto the crystal substrate; A third step of interrupting the supply of the Si source and the group III source onto the crystal substrate; and stopping the supply of the Si source and the group III source onto the crystal substrate; After supplying the group V raw material onto the crystal substrate, supplying a group V raw material, a Si raw material, and a group III raw material onto the crystal substrate, and performing crystal growth of a III-V compound semiconductor crystal layer. III-V
A vapor phase growth method for a group III compound semiconductor. 3. The crystal substrate according to claim 1, wherein the outermost surface layer of the crystal substrate on which the III-V compound semiconductor crystal layer is formed contains Si. A vapor phase growth method for a III-V compound semiconductor. 4. The crystal substrate according to claim 1, wherein the outermost surface layer of the crystal substrate on which the III-V compound semiconductor crystal layer is formed contains Al. A vapor phase growth method for a III-V compound semiconductor. 5. The method according to claim 1, wherein in the first step, the temperature of the crystal substrate on which the III-V compound semiconductor crystal layer is formed is raised to a temperature of 600 ° C. or more and 850 ° C. or less. Item 5. The method for vapor-phase growth of a group III-V compound semiconductor according to any one of items 1 to 4. 6. The method according to claim 1, wherein the second step includes a period in which the temperature of the crystal substrate on which the III-V compound semiconductor crystal layer is formed is 550 ° C. or more and 650 ° C. or less. III- according to any one of claims 1 to 5.
A vapor phase growth method for a group V compound semiconductor. 7. The method according to claim 1, wherein Si is used as the n-type additive impurity.
A III-V compound semiconductor light-emitting device, which is manufactured using the method for vapor-phase growing a III-V compound semiconductor according to claim 1.