JP2001326385A - Method of manufacturing semiconductor light-emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a high-quality nitride III-V compound semiconductor light-emitting element, by which problem of nonuniformity in mixed crystal composition of a nitride III-V compound semiconductor layer is settled, especially for improved uniformity in mixed crystal, when indium is contained. SOLUTION: A manufacturing method of a semiconductor light-emitting element such as a laser diode is provided which comprises a process where, by an organic metal chemical vapor-phase growth method, the nitride III-V compound semiconductor layer containing indium and the like is crystal-grown and formed. Here, the flow velocity of material gas 34 containing ammonia gas and the like in a reactive tube 30 for crystal growth is set to 3-5 m/s while the pressure in the reactive tube is set to higher than a normal pressure, to form at least a part of the III-V compound semiconductor layer such as a light- emitting layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a group III-V compound semiconductor light-emitting device containing nitrogen (hereinafter also referred to as a nitride-based compound), and more particularly to a method of crystal growth by metal organic chemical vapor deposition. The present invention relates to a method for manufacturing a semiconductor light emitting device that forms a nitride III-V compound semiconductor light emitting layer.

[0002]

2. Description of the Related Art A nitride-based III-V compound semiconductor represented by gallium nitride (GaN) (hereinafter also referred to as a "GaN-based semiconductor") emits light that can emit light in a range from green to blue and even ultraviolet rays. It is promising as a material for devices and the like. In particular, since the light-emitting diode (LED) using the GaN-based semiconductor was put to practical use, GaN-based semiconductors have received a great deal of attention. The realization of a semiconductor laser using this GaN-based semiconductor has also been reported,
A device that reads (reproduces) information recorded on an optical recording medium (hereinafter, also referred to as an optical disc) such as a digital versatile disc (hereinafter also referred to as an optical disc) or writes (records) information to or from them. The optical pickup device is also expected to be applied to an optical pickup device incorporated therein.

FIG. 1 shows the above-mentioned Ga having a general structure.
FIG. 3 is a perspective view of an N-based semiconductor light emitting device (laser diode LD). A GaN-based semiconductor layer including an active layer 16 having a multiple quantum well structure is stacked on a sapphire substrate 11 to form a semiconductor stacked body 10. In the semiconductor laminate 10, a p-type electrode 10a and an n-type electrode 10b are formed so as to be connected to the p-type clad layer and the n-type clad layer formed so as to sandwich the active layer 16, respectively. I have. Here, since the sapphire substrate 11 is insulative, the semiconductor layer connected to the n-type cladding layer or n
The lead portion 10c of the mold cladding layer itself is formed on the sapphire substrate 11 so as to protrude from the semiconductor laminate 10, and the n-type electrode 10b is formed on this upper layer. A power supply B is connected to the p-electrode 10a and the n-electrode 10b.
When a predetermined voltage is applied, the laser light L is emitted from the active layer 16 in the semiconductor laminate 10.

FIG. 2A is a cross-sectional view illustrating the above-described semiconductor laminate 10 in more detail. For example, a buffer layer 12 made of GaN or the like is formed on a sapphire substrate 11.
Is formed thereon, and for example, about 5.0 μm
GaN layer 13 doped with Si having a thickness of about 0.5 μm
AlGaN layer 14 doped with Si having a thickness of
A multi-quantum well (MQ) made of Si-doped GaN layer 15 having a thickness of
W) Active layer (light-emitting layer) 16 having a structure, AlGaN layer 17 doped with Mg having a thickness of about 0.02 μm, about 0.1 μm
GaN layer 18 doped with Mg having a thickness of about 0.5 μm
AlGaN layer 19 doped with Mg having a thickness of
Each of the GaN layers 20 doped with Mg having a thickness of μm is laminated.

FIG. 2B is a schematic diagram showing the potential of the active layer 16 having the above-described multiple quantum well structure. In the active layer 16, layers having an indium (In) content of 2% and layers having an indium content of 8% are alternately stacked, and the potentials of the respective layers are different, so that a multiple quantum well structure is formed. .

A method for manufacturing the above-mentioned GaN-based semiconductor light emitting device (laser diode LD) will be described. G above
When manufacturing a light emitting element or the like from an aN-based semiconductor,
It is necessary to grow a GaN-based semiconductor in multiple layers on a sapphire substrate, a SiC substrate, or the like. As a method for growing the GaN-based semiconductor, there is known a metal organic chemical vapor deposition (MOCV) method.
There are D) method and molecular beam epitaxy (MBE) method. Of these methods, MOCVD method is practically advantageous because it does not require a high vacuum, and is widely used.

FIG. 3 is a schematic view of an example of the above MOCVD apparatus. The MOCVD reaction tube (hereinafter, simply referred to as a reaction tube) 30 is made of a material having sufficient strength and being thermally stable.
For example, it is formed of quartz glass or the like. Reaction tube 3
0, a susceptor 31 made of, for example, graphite is provided, and a substrate 32 to be grown on the susceptor 31 is grown.
Is placed and processed. An RF coil 33 is provided so as to surround the outer periphery of the reaction tube 30.
The susceptor 31 is heated by the induction heating by the F coil 33, and the substrate 32 to be processed is heated by the heat conduction from the susceptor 31.
Is heated. A source gas 34 containing ammonia gas is supplied to the heated susceptor 31 and the substrate 32 to be processed. The raw material gas 34 containing ammonia and the like supplied into the above-described reaction tube 30 is supplied to a hydrogen gas supply unit 35, an ammonia gas supply unit 36 and a raw material gas supply unit 37 by a mass flow controller (MFC) 38 and an intake valve 39. The raw material gas is supplied from a raw material gas supply path 40 connected through the air. Unnecessary gas in each source gas supply path 40 and the reaction tube 30 is discharged to an exhaust gas treatment device 43 via an exhaust valve 41, a source gas delivery unit 42, and the like.

When a GaN-based semiconductor is grown by MOCVD, a raw material such as gallium (Ga), aluminum (Al), or indium (In) is placed in a reaction tube of an MOCVD apparatus, depending on the GaN-based semiconductor to be grown. By supplying the carrier gas together with the carrier gas into the reaction tube 30 and simultaneously supplying ammonia (NH ₃ ) as a nitrogen raw material into the reaction tube, the GaN-based semiconductor is placed on the substrate 32 to be processed placed in the reaction tube 30. Grow.

A process for growing a GaN-based semiconductor in multiple layers using the MOCVD apparatus having the above configuration will be described. First, as shown in FIG. 4A, a buffer layer 12 made of GaN or the like, a GaN layer 13 doped with Si having a thickness of about 5.0 μm, a GaN layer 13 having a thickness of about 0.5 μm are formed on a sapphire substrate 11 by MOCVD. AlGaN layer 14 doped with Si having a thickness of about 0.1 μm and S
A GaN layer 15 doped with i is formed by sequentially growing crystals.

[0010] Next, as shown in FIG.
According to the D method, a multiple quantum well (MQ) made of, for example, GaInN doped with Si is formed on the GaN layer 15 doped with Si.
An active layer (light emitting layer) 16 having a W) structure is formed by crystal growth. At this time, the reaction tube 3 of the MOCVD apparatus shown in FIG.
0 (ie, the flow rate of the source gas at the growth pressure (m ³ / s) / the value of the cross-sectional area of the reaction tube (m
² )) is about 1 m / s.

Next, an Al layer doped with Mg having a thickness of about 0.02 μm is formed on the active layer 16 by MOCVD.
A GaN layer 17, a GaN layer 18 doped with Mg having a thickness of about 0.1 μm, an AlGaN layer 19 doped with Mg having a thickness of about 0.5 μm, and a Mg layer having a thickness of about 0.1 μm.
A GaN layer 20 doped with is formed by crystal growth in order to reach the structure shown in FIG. In the subsequent steps, a lead portion 10c of the n-type cladding layer itself shown in FIG. 1 is formed by etching, electrodes (10a, 10b) are formed, and a laser cavity end face is formed by etching or the like. A desired laser diode can be obtained.

[0012]

However, when the nitride III-V compound semiconductor layer containing indium (In) is crystal-grown in the above-mentioned manufacturing method, it is difficult for the mixed crystal composition of indium to be uniform. And, as a result, a nitride system III- containing indium having non-uniform crystallinity.
There is a problem that only a group V compound semiconductor layer can be obtained.

FIG. 6 (b) shows that the light emitting layer having a non-uniform mixed crystal composition of indium formed by the above-described conventional method is used.
It is an emission spectrum in photoluminescence when a He-Cd laser having an emission wavelength of 325 nm is irradiated as excitation light. As shown in FIG. 6B, when the mixed crystal composition of indium is non-uniform, a sub-peak component exists on both shoulders of a main peak on an emission spectrum so that a plurality of light-emitting components are mixed. In addition, the full width at half maximum of the emission spectrum is wide, and the emission characteristics are inferior.

Accordingly, an object of the present invention is to provide a nitride III
-Eliminating the non-uniformity of the mixed crystal composition in the group V compound semiconductor layer and improving the uniformity of the mixed crystal composition particularly when indium is contained, thereby producing a high-quality nitride-based III-V compound semiconductor light emitting device. Is to provide a way that can be done.

[0015]

In order to achieve the above object, a method for manufacturing a semiconductor light emitting device according to the present invention comprises the steps of: growing a group III-V compound semiconductor layer containing nitrogen by a metalorganic chemical vapor deposition method; A method of manufacturing a semiconductor light emitting device having a step of forming a semiconductor light emitting device, wherein a flow rate of a source gas in a reaction tube in which the crystal growth is performed is 3 m / s or more and 5 m / s.
and forming at least a part of the group III-V compound semiconductor layer.

Nitride-based I by metalorganic chemical vapor deposition
When the II-V compound semiconductor layer is crystal-grown, a method of controlling the gas phase reaction between the source gases is to shorten the time from the mixing of the source gases to the thermal decomposition on the substrate surface to form crystals. Was found to be effective, and it was discovered that it was important to increase the flow rate of the source gas in order to shorten the time during which the mixed source gas was supplied to the substrate surface.

On the other hand, when a nitride III-V compound semiconductor crystal is grown by metal organic chemical vapor deposition,
If the flow rate of the raw material gas is too high, the flow of the raw material gas will be disturbed, which causes the mixed crystal composition to be non-uniform. Therefore, it is also important not to make the flow rate of the source gas too high.

That is, the method of manufacturing a semiconductor light emitting device according to the present invention comprises the steps of:
When forming the group IV compound semiconductor layer by crystal growth, the flow rate of the source gas in the reaction tube for crystal growth is set to 3 m / s or more, and after the source gases are mixed, the surface of the substrate is It is possible to shorten the time required for thermal decomposition to form crystals. As a result, a gas phase reaction between source gases can be controlled, and a nitride III-V compound semiconductor layer having good mixed crystal composition uniformity can be formed. Further, the flow rate of the raw material gas in the reaction tube is set to 5
m / s or less, the turbulence of the flow of the source gas can be suppressed, and the uniformity of the mixed crystal composition can be improved in the production of the nitride-based III-V compound semiconductor layer. As described above, a high-quality nitride III-V compound semiconductor light-emitting device can be manufactured by the method for manufacturing a semiconductor light-emitting device of the present invention.

In the method of manufacturing a semiconductor light emitting device of the present invention, preferably, the flow rate of the source gas in the reaction tube for performing the crystal growth is set to 3 m / s or more and 5 m / s or less, and In the step of forming at least a part of the group V compound semiconductor layer, a III-V compound semiconductor light emitting layer is formed. More preferably, a light emitting layer containing indium is formed as the III-V compound semiconductor light emitting layer. Alternatively, more preferably, the above III-
A light emitting layer having a multiple quantum well structure containing indium is formed as a group V compound semiconductor light emitting layer. In the light emitting layer having a multiple quantum well structure containing indium, for example,
By improving the uniformity of the mixed crystal composition and the device characteristics, a high-quality nitride-based III-V compound semiconductor light-emitting device can be manufactured.

In the above method for manufacturing a semiconductor light emitting device of the present invention, preferably, the raw material gas contains ammonia gas.
The flow rate of the source gas containing ammonia gas in the reaction tube is 3 m
/ S or more and the nitride-based III-V compound semiconductor light-emitting layer is grown so that more nitrogen source species contributing to the growth are supplied onto the substrate to be processed, and Since the evaporation of nitrogen from the compound III-V compound semiconductor film is suppressed, the resulting nitride II
The nitrogen deficiency in the IV compound semiconductor film is eliminated. The source gas containing ammonia gas supplied to the reaction tube is heated by the susceptor for heating the substrate to be processed or the heated substrate to be processed and is supplied onto the substrate to be processed. If the flow rate is too high, the ammonia is not sufficiently heated, and the decomposition efficiency is extremely reduced, thereby increasing the number of nitrogen vacancies in the nitride-based III-V compound semiconductor and causing deterioration in crystallinity. However, by setting the flow rate of the raw material gas containing the ammonia gas in the reaction tube to 5 m / s or less, the crystallinity can be improved without increasing the number of nitrogen vacancies.
As described above, a nitride III-V compound semiconductor film having improved crystallinity can be obtained, and a high-quality nitride II
A group IV compound semiconductor light emitting device can be manufactured.

In the method for manufacturing a semiconductor light emitting device of the present invention, preferably, in the step of forming at least a part of the group III-V compound semiconductor layer, the pressure in the reaction tube for performing the crystal growth is further reduced. The crystal is grown at a pressure higher than normal pressure. When the pressure of the raw material gas in the reaction tube is set to a pressure higher than the normal pressure, the nitride-based material with significantly improved crystallinity is compared with the conventional case where the reaction tube is grown at normal pressure or reduced pressure. A III-V compound semiconductor film can be obtained.

In the method of manufacturing a semiconductor light emitting device according to the present invention, a laser diode is preferably formed as the semiconductor light emitting device. A semiconductor light emitting element that operates as a laser diode is required to have particularly uniform element characteristics, but a high-quality nitride III-V compound semiconductor film can be obtained by the method for manufacturing a semiconductor light emitting element of the present invention. Therefore, it is suitable for manufacturing a laser diode.

The nitride III-V compound semiconductor manufactured by the method for manufacturing a semiconductor light emitting device of the present invention described above comprises:
At least one group III element selected from the group consisting of Ga, Al, In and B, and at least N;
In some cases, the present invention can be preferably applied to a group III-V compound semiconductor comprising a group V element containing As or P. Specific examples of the nitride-based group III-V compound semiconductor include GaN, AlN, InN, and AlGaN. , GaI
nN, AlGaInN, and the like can be given. In particular, In tends to cause non-uniformity of the mixed crystal composition and causes deterioration of device characteristics. In the present invention, however, the uniformity of the mixed crystal composition is improved, and a high-quality nitride III-V compound is improved. A semiconductor film can be obtained.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a semiconductor light emitting device and a method for manufacturing the same according to the present invention will be described below with reference to the drawings. In all the drawings of the embodiments, the same or corresponding portions are denoted by the same reference numerals.

FIG. 1 shows a nitride III according to this embodiment.
FIG. 2 is a perspective view of a GaN-based semiconductor light-emitting device (laser diode LD) that is a group V compound semiconductor light-emitting device. On a sapphire substrate 11, a GaN-based semiconductor layer, which is a group III-V compound semiconductor including an active layer 16 having a multiple quantum well structure, is laminated to form a semiconductor laminate 10. In the semiconductor laminate 10, a p-type electrode 10a and an n-type electrode 10b are formed so as to be connected to the p-type clad layer and the n-type clad layer formed so as to sandwich the active layer 16, respectively. I have. Here, since the sapphire substrate 11 is insulative, the lead portion 10 of the semiconductor layer connected to the n-type cladding layer or the n-type cladding layer itself is used.
c is formed on the sapphire substrate 11 so as to protrude from the semiconductor laminate 10, and the n-type electrode 10 b is formed on this upper layer. By applying a predetermined voltage from the power supply B to the p-electrode 10a and the n-electrode 10b,
Laser light L is emitted from the active layer 16 in the semiconductor laminate 10.

FIG. 2A is a cross-sectional view for explaining in more detail the portion of the semiconductor laminate 10 which is the GaN-based compound. For example, a buffer layer 12 made of GaN or the like is formed on a sapphire substrate 11, and
For example, GaN doped with Si having a thickness of about 5.0 μm
Layer 13, AlG doped with about 0.5 μm thick Si
aN layer 14, G doped with about 0.1 μm thick Si
an active layer (light emitting layer) 16 having a multiple quantum well (MQW) structure made of GaInN or the like doped with Si,
AlGaN layer 17 doped with Mg having a thickness of about 0.02 μm, GaN layer 18 doped with Mg having a thickness of about 0.1 μm, AlGa doped with Mg having a thickness of about 0.5 μm
N layer 19, Ga doped with Mg having a thickness of about 0.1 μm
The N layers 20 are respectively stacked.

FIG. 2B is a schematic diagram showing the potential of the active layer 16 having the multiple quantum well structure. In the active layer 16, layers having an indium (In) content of 2% and layers having an indium content of 8% are alternately stacked, and the potentials of the respective layers are different, so that a multiple quantum well structure is formed. .

A method of manufacturing the GaN-based semiconductor light emitting device (laser diode LD) will be described. G above
When manufacturing a light emitting element or the like from an aN-based semiconductor,
It is necessary to grow a GaN-based semiconductor in multiple layers on a sapphire substrate, a SiC substrate, or the like. As a method for growing the GaN-based semiconductor, there is known a metal organic chemical vapor deposition (MOCV) method.
D) method, molecular beam epitaxy (MBE) method, or the like can be used.

FIG. 3 is a schematic diagram of an example of the above MOCVD apparatus. The MOCVD reaction tube (hereinafter, simply referred to as a reaction tube) 30 is made of a material having sufficient strength and being thermally stable.
For example, it is formed of quartz glass or the like. The wall of the reaction tube 30 is formed sufficiently thick so that it can withstand the external pressure, that is, the pressure of the atmospheric pressure even when the internal pressure of the reaction tube 30 becomes 2 atm. A susceptor 31 made of, for example, graphite is provided inside the reaction tube 30, and a substrate 32 to be grown which is to be grown is placed on the susceptor 31 for processing. An RF coil 33 is provided so as to surround the outer periphery of the reaction tube 30.
The susceptor 31 is heated by the induction heating by 3, and the substrate 32 is heated by heat conduction from the susceptor 31. In the heated susceptor 31 and the substrate 32 to be processed,
A source gas 34 containing ammonia gas is supplied. The source gas 34 containing ammonia and the like supplied into the above-described reaction tube 30 is supplied to a hydrogen gas supply unit 35, an ammonia gas supply unit 36, and a source gas supply unit 37 by a mass flow controller (MFC) 38 and an intake valve 39. The raw material gas is supplied from a raw material gas supply path 40 connected through the air. Also,
Unnecessary gas in each source gas supply path 40 and the reaction tube 30 is discharged to an exhaust gas treatment device 43 via an exhaust valve 41, a source gas delivery unit 42, and the like.

When a GaN-based semiconductor is grown by the MOCVD method, raw materials such as gallium (Ga), aluminum (Al), and indium (In) are placed in a reaction tube of the MOCVD apparatus according to the GaN-based semiconductor to be grown. By supplying the carrier gas together with the carrier gas into the reaction tube 30 and simultaneously supplying ammonia (NH ₃ ) as a nitrogen raw material into the reaction tube, the GaN-based semiconductor is placed on the substrate 32 to be processed placed in the reaction tube 30. Grow. The source gas including the ammonia gas and the like flowing inside the reaction tube 30 is used to control the flow rate of the source gas inside the reaction tube 30 by changing the supply amount of the source gas and the pressure inside the reaction tube 30. Can be.

A process for growing a GaN-based semiconductor in multiple layers using the MOCVD apparatus having the above-described configuration will be described. First, as shown in FIG. 4A, a buffer layer 12 made of GaN or the like, a GaN layer 13 doped with Si having a thickness of about 5.0 μm, a GaN layer 13 having a thickness of about 0.5 μm are formed on a sapphire substrate 11 by MOCVD. AlGaN layer 14 doped with Si having a thickness of about 0.1 μm and S
A GaN layer 15 doped with i is formed by sequentially growing crystals.

Next, as shown in FIG.
According to the D method, a multiple quantum well (MQ) made of, for example, GaInN doped with Si is formed on the GaN layer 15 doped with Si.
An active layer (light emitting layer) 16 having a W) structure is formed by crystal growth.

Next, an Al layer doped with Mg having a thickness of about 0.02 μm was formed on the active layer 16 by MOCVD.
A GaN layer 17, a GaN layer 18 doped with Mg having a thickness of about 0.1 μm, an AlGaN layer 19 doped with Mg having a thickness of about 0.5 μm, and a Mg layer having a thickness of about 0.1 μm.
A GaN layer 20 doped with is formed by crystal growth in order to reach the structure shown in FIG. In the subsequent steps, a lead portion 10c of the n-type cladding layer itself shown in FIG. 1 is formed by etching, electrodes (10a, 10b) are formed, and a laser cavity end face is formed by etching or the like. A desired laser diode can be obtained.

In the step of forming at least a part of the group III-V compound semiconductor layer by the MOCVD method, an active layer (light emitting layer) 16 having a multiple quantum well (MQW) structure made of, for example, GaInN doped with Si is formed. In the crystal growth step, the flow rate of the source gas in the reaction tube 30 of the MOCVD apparatus shown in FIG. 3 (that is, the flow rate of the source gas at the growth pressure (m ³ / s) / the value of the cross-sectional area of the reaction tube (m ² )) )) Is set to 3 m / s or more and 5 m / s or less. For example, in order to deposit a GaInN film, a mixed gas of a hydrogen gas, an ammonia gas and an organic metal material gas which is an organic compound of Ga and In is supplied.
The flow rate of the mixed raw material gas in the reaction tube in the OCVD apparatus is set to 3 m / s or more and 5 m / s or less. To have a multiple quantum well (MQW) structure, I
In the case of alternately laminating the layers having the n content of 2% and the layer of 8%, the layers can be formed by changing the partial pressure of the In compound in the source gas.

Further, the pressure in the reaction tube is preferably set to a pressure higher than the normal pressure, for example, set to 1.6 atm. The processing temperature (susceptor temperature) in the MOCVD process is, for example, about 785 to 800 ° C. in the case of an active layer containing In, and is, for example, about 1000 ° C. in other cases.

In order to examine the light emission characteristics of the active layer (light emitting layer) having a multiple quantum well (MQW) structure made of GaInN formed as described above, a photoluminescence method is widely used. In the photoluminescence method,
For example, when a target film is irradiated with He-Cd laser light having an emission wavelength of 325 nm as excitation light, emission emitted from the target film is measured by performing spectroscopy or the like. As described above, it is necessary to irradiate the target film with He-Cd laser light. Therefore, the upper layer of the target film has a thickness enough to transmit the laser light (for example, 100 μm for a GaN film).
An element for measurement having only a film having a thickness of about nm) is prepared.

FIG. 5 is a cross-sectional view of the above-described device dedicated to photoluminescence measurement. For example, sapphire substrate 1
1, a buffer layer 12 made of GaN or the like is formed.
A layer 21, an active layer (light emitting layer) 22 having a multiple quantum well (MQW) structure made of SiIn-doped GaInN or the like, and a Si-doped GaN layer 2 having a thickness of about 100 nm.
3 are laminated. In the above configuration, Ga
The active layer 22 is irradiated with the He-Cd laser light L by passing through the N layer 23, and the light emission PL emitted from the active layer 22 is emitted.
Is measured.

FIG. 6A shows that the flow rate of the raw material gas is 3 m.
5 is a photoluminescence emission spectrum of an active layer (light emitting layer) 22 having a multiple quantum well (MQW) structure formed at a rate not less than / s and not more than 5 m / s. FIG. 6 showing a conventional example
In FIG. 6A of the present invention, the intensity of the sub-peak component present at both shoulders of the main peak as seen in the spectrum shown in FIG. This indicates that the full width at half maximum of the emission spectrum was narrowed, and the emission characteristics were able to be improved.

FIG. 7 is a diagram in which the value of the full width at half maximum of the photoluminescence emission spectrum is plotted against the flow rate of the source gas. As shown in FIG. 7, when the flow rate of the source gas containing ammonia is increased, the full width at half maximum of the emission spectrum of photoluminescence is reduced, specifically, 3 m / s.
From the above, it was found that the value was almost constant. This is because the spatial fluctuation of the mixed crystal composition of indium in the formed nitride III-V compound semiconductor multiple quantum well structure is reduced,
This shows that the uniformity of the emission wavelength is improved. That is, when performing vapor phase growth of the nitride III-V compound semiconductor light emitting layer, the flow rate of the source gas containing ammonia is set to 3 m.
By adjusting so as to be larger than / s, the quality of the grown crystal can be improved.

Further, when the flow rate of the source gas containing ammonia is larger than 5 m / s, the full width at half maximum of the emission spectrum of photoluminescence is increased. This is because, when the flow rate of the source gas is set to be greater than 5 m / s, the flow of the source gas is disturbed, and the uniformity of the nitride III-V compound semiconductor light emitting layer is reduced. -V
This is because the rate of non-radiative recombination caused by a crystal defect or the like of the group III compound semiconductor decreases, and the luminous intensity of photoluminescence increases. That is, by adjusting the flow rate of the source gas containing ammonia to 5 m / s or less, the quality of the grown crystal can be improved.

In the method of the present invention, the nitride III-V
In the case of performing vapor phase growth of a group III compound semiconductor, the inside of the reaction tube can be similarly performed under normal pressure, reduced pressure, or any pressure under pressure, and in any case, a raw material containing ammonia By specifying the gas flow rate within the above-mentioned predetermined range, a nitride III-V having excellent crystallinity can be obtained.
An element having a group III compound semiconductor light emitting layer can be manufactured. In particular, in a GaN-based compound semiconductor, the high saturation vapor pressure makes it easier for nitrogen atoms to evaporate from the GaN-based compound semiconductor film during vapor phase growth. As a result, the obtained GaN-based compound semiconductor film becomes insufficient in nitrogen, and the film quality may be impaired. Therefore, by intentionally performing gas phase growth under a pressure higher than 1 atm in the reaction tube, more nitrogen source species can be supplied onto the substrate, and the growing GaN-based compound can be supplied. Evaporation of nitrogen atoms from the semiconductor film can also be suppressed, and nitrogen deficiency in the obtained GaN-based compound semiconductor film can be avoided, so that a high-quality GaN-based compound semiconductor film can be manufactured.

In the above-described embodiment of the method of the present invention, the RF coil 33 is used to heat the susceptor 31 in the reaction tube 30. However, the present invention is not limited to this example, and is conventionally known. The susceptor 31 can be heated using a heater.

According to the method for manufacturing a semiconductor light emitting device according to the present embodiment, when a group III-V compound semiconductor layer containing nitrogen is formed by crystal growth by metal organic chemical vapor deposition, crystal growth is performed. By setting the flow rate of the raw material gas in the reaction tube to be 3 m / s or more, the time from mixing of the raw material gases to thermal decomposition on the substrate surface to form crystals can be shortened, and the surface of the substrate to be processed can be reduced. Enough nitrogen source species to be supplied, thereby making it possible to form a nitride-based III-V compound semiconductor layer having a small number of non-radiative recombination centers and excellent crystallinity. 5
By setting the flow rate to m / s or less, disturbance of the flow of the source gas can be suppressed, and the uniformity of the mixed crystal composition can be improved. Therefore, a high-quality nitride III-V compound semiconductor light emitting device Can be manufactured.

Using the laser diode according to the present embodiment, it is possible to preferably configure a laser coupler mounted on an optical pickup device for an optical disk device.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to these embodiments. For example, the light emitting wavelength of the light emitting device according to the present invention is not particularly limited, and may be a wavelength employed in DVD or other next-generation optical disk systems. In the embodiment, a laser diode is described. However, the present invention is not limited to a laser, but can be applied to a light emitting diode (LED). In addition, the present invention can be applied to other GaN-based semiconductor layer forming steps such as a GaN layer forming step in addition to the GaInN layer forming step. Further, a semiconductor light emitting device in which a plurality of light emitting elements are monolithically configured can be manufactured by using the manufacturing method of the present invention. In this case, for example, a light-emitting device having a plurality of light-emitting elements such as light-emitting elements with different emission wavelengths, light-emitting elements with different element characteristics such as the same emission wavelength and different emission intensity, and further, a light-emitting element with the same element characteristic. It is possible to apply. Although the current constriction structure of the laser diode is not shown in detail in the embodiment, it can be applied to other lasers having various characteristics such as a gain guide type, an index guide type, and a pulsation laser. is there. In addition, various changes can be made without departing from the spirit of the present invention.

[0046]

According to the method of manufacturing a semiconductor light emitting device of the present invention, a nitrogen-containing I
When the group II-V compound semiconductor layer is formed by crystal growth, the flow rate of the source gas in the reaction tube where the crystal growth is performed is set to 3 m / s or more, so that the source gases are mixed with each other before the substrate surface is mixed. It is possible to shorten the time required for thermal decomposition to form a crystal, and to supply a sufficient amount of nitrogen source species to the surface of the substrate to be treated. A group V compound semiconductor layer can be formed, and the flow rate of the source gas is 5 m / s
By setting the following, it is possible to suppress the disturbance of the flow of the source gas and improve the uniformity of the mixed crystal composition, so that a high-quality nitride-based III-V compound semiconductor light-emitting device is manufactured. be able to.

[Brief description of the drawings]

FIG. 1 is a perspective view of a semiconductor light emitting device (laser diode) according to the present invention and a conventional example.

2A is a cross-sectional view of a semiconductor laminate portion of the semiconductor light emitting device shown in FIG. 1, and FIG. 2B is a potential diagram of an active layer.

FIG. 3 is a schematic configuration diagram of an MOCVD apparatus.

FIG. 4 is a cross-sectional view illustrating a manufacturing process of a method for manufacturing a semiconductor light emitting device according to the present invention and a conventional example.
(A) shows up to the step of forming the lower layer of the active layer, and (b) shows the step up to the step of forming the active layer.

FIG. 5 is a sectional view of an element dedicated to photoluminescence measurement.

FIG. 6 is a photoluminescence emission spectrum of an active layer of a semiconductor light emitting device according to (a) the present invention and (b) a conventional example.

FIG. 7 is a diagram in which the value of the full width at half maximum of the photoluminescence emission spectrum is plotted against the flow rate of the source gas.

[Explanation of symbols]

10 semiconductor laminate, 10a p-electrode, 10b n-electrode, 10c lead-out part, 11 sapphire substrate, 12
... buffer layer, 13 ... GaN layer doped with Si, 14
... AlGaN layer doped with Si, 15 ... GaN layer doped with Si, 16 ... Active layer (light emitting layer), 17 ... AlGaN layer doped with Mg, 18 ... Ga doped with Mg
N layer, 19 ... AlGaN layer doped with Mg, 20 ... M
g doped GaN layer, 21... Si doped Ga
N layer, 22: active layer (light emitting layer), 23: GaN layer doped with Si, 30: reaction tube, 31: susceptor, 32: substrate to be processed, 33: RF coil, 34: source gas, 35 ...
Hydrogen gas supply unit, 36 ... Ammonia gas supply unit, 37 ...
Material gas supply unit, 38: Mass flow controller (MF
C), 39: intake valve, 40: source gas supply path, 41: exhaust valve, 42: source gas delivery unit, 43: exhaust gas treatment device,
B: power supply, L: laser light, LD: laser diode.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yuki Asazuma 6-35 Kita Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F-term (reference) 5F041 AA11 AA40 CA05 CA34 CA40 CA46 CA49 CA65 FF16 5F045 AA04 AB09 AB14 AB17 AB18 AC08 AC12 AD11 AD12 AD14 AE30 AF09 BB04 BB12 CA12 DA55 EE12 EE17 EK03 5F073 AA74 CA07 CB05 CB07 DA05 DA06 DA35 EA29

Claims (7)

[Claims] 1. A method for manufacturing a semiconductor light emitting device, comprising: forming a nitrogen-containing group III-V compound semiconductor layer by crystal growth by a metal organic chemical vapor deposition method. The flow rate of the source gas in the pipe is set to 3 m / s or more and 5 m / s or less, and the above III
-A method for manufacturing a semiconductor light emitting device, comprising a step of forming at least a part of a group V compound semiconductor layer. 2. The step of forming at least a part of the group III-V compound semiconductor layer by setting a flow rate of a source gas in a reaction tube for performing crystal growth to be 3 m / s or more and 5 m / s or less, 2. The method for manufacturing a semiconductor light emitting device according to claim 1, wherein a III-V compound semiconductor light emitting layer is formed. 3. The method according to claim 2, wherein a light emitting layer containing indium is formed as the III-V compound semiconductor light emitting layer. 4. The method of manufacturing a semiconductor light emitting device according to claim 2, wherein a light emitting layer having a multiple quantum well structure containing indium is formed as the III-V compound semiconductor light emitting layer. 5. The method according to claim 1, wherein said source gas contains ammonia gas. 6. The method according to claim 1, wherein in the step of forming at least a part of the group III-V compound semiconductor layer, the pressure in the reaction tube for performing the crystal growth is set to a pressure higher than normal pressure, and the crystal is grown. The manufacturing method of the semiconductor light emitting device according to the above. 7. The method for manufacturing a semiconductor light emitting device according to claim 1, wherein a laser diode is formed as said semiconductor light emitting device.