JP2001358082A - Method of growing semiconductor layer and semiconductor light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of growing a semiconductor layer such as a GaN layer grown in excellent crystal having a small number of through dislocations and a semiconductor light emitting device formed through the same. SOLUTION: A groove G having an inner side nearly vertical to the main surface of a substrate is provided to the III-V compound semiconductor substrate such as a GaN substrate, extending in a prescribed direction such as a <1-100> direction or a <11-20> direction, and a III-V compound semiconductor layer such as a GaN layer is made to grow through a vapor growth method under conditions that a growth rate in the direction of the main surface of the substrate 30 is set faster than that in the direction vertical to the main surface of the substrate 30. Before a vapor growth is carried out, mask layers (33a and 33b) may be formed on the surface of the substrate 30 except the base of the groove G and a groove G forming region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for growing a semiconductor layer and a semiconductor light-emitting device, and more particularly, to a method for growing a III-V compound semiconductor layer containing nitrogen (hereinafter also referred to as nitride). And a semiconductor light emitting device using a semiconductor layer grown by this method.

[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. 13 is a perspective view of the GaN-based semiconductor light-emitting device (laser diode LD ') having a general structure using an insulating sapphire substrate. 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, the active layer 1
The p-type electrode 10 is connected to each of the p-type cladding layer and the n-type cladding layer formed so as to sandwich
The a and n electrodes 10b are respectively formed. here,
Since the sapphire substrate 11 is insulative, the semiconductor layer connected to the n-type cladding layer or the lead-out portion 10c of the n-type cladding layer itself is formed on the sapphire substrate 11 so as to protrude from the semiconductor laminate 10. The n-electrode 10b is formed on this upper layer. P above
When a predetermined voltage is applied from the power supply B to the electrode 10a and the n-electrode 10b, the laser light L is emitted from the active layer 16 in the semiconductor laminate 10.

The above laser diode LD 'has a MOC
A sapphire substrate is mainly used as a substrate formed by a crystal growth method such as a metal organic chemical vapor deposition (VD) method.
However, a lattice mismatch between the sapphire substrate and the GaN film is large, and a large number of threading dislocations are introduced into a grown semiconductor laminate such as a GaN film, thereby lowering the reliability of the device.

Therefore, for example, GaN is formed on a sapphire substrate.
After the film is grown to a thickness of 2 μm, the GaN film is processed into a ridge structure in which the GaN film protrudes on the sapphire substrate by RIE (reactive ion etching) or the like.
Attempts have been made to obtain a high-quality crystal region with less threading dislocation by changing the direction of threading dislocation by laterally growing the film from the side surface and converging it.

In recent years, GaN substrates formed by the HVPE (hydride vapor phase epitaxy) method have been produced, and instead of sapphire substrates, GaN substrates have been developed.
It has been used as a substrate for growing an aN film. A semiconductor laminate using a GaN substrate can grow a GaN film of higher quality than a sapphire substrate in terms of lattice matching. In addition, since the GaN substrate has conductivity, a p-electrode and an n-electrode can be formed on the upper and lower surfaces of the semiconductor laminate, respectively, and the size of the device can be reduced. In addition, since it has cleavage, it is easy to form a laser cavity end face.

FIG. 10 is a perspective view of a GaN-based semiconductor light emitting device (laser diode LD) using a GaN substrate. An active layer 1 having a multiple quantum well structure on a GaN substrate 11
The semiconductor stacked body 10 is formed by stacking GaN-based semiconductor layers including the semiconductor layers 6. 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. When a predetermined voltage is applied to the p-electrode 10a and the n-electrode 10b by the power supply B, the active layer 1 in the semiconductor laminate 10
The laser light L is emitted from 6.

[0008]

However, as the GaN substrate formed by the above-mentioned conventional HVPE method,
Since a high-quality crystal with sufficiently few threading transitions has not been obtained, even if a GaN layer is grown on the GaN substrate by MOCVD or the like, the threading transition of the GaN substrate is inherited as it is, and the characteristics It has been difficult to obtain a device with good performance.

Accordingly, an object of the present invention is to provide a method for growing a semiconductor layer such as a GaN layer capable of growing a high-quality crystal with little threading dislocation, and a semiconductor light emitting device using the semiconductor layer thus grown. It is to provide.

[0010]

In order to achieve the above object, a method of growing a semiconductor layer according to the present invention comprises the steps of: providing a group III-V compound substrate with an inner surface substantially perpendicular to a main surface of the substrate; Having a step of forming a groove extending in a predetermined direction, and a growth rate in a direction perpendicular to the main surface of the substrate,
A step of vapor-phase growing a group III-V compound semiconductor layer on the substrate on which the groove is formed, under conditions where the growth rate of the substrate in the main surface direction is high.

In the method for growing a semiconductor layer according to the present invention, preferably, after the step of forming the groove, the semiconductor layer is formed on the substrate.
Before the step of vapor-phase growing an IV compound semiconductor layer,
Forming a mask layer on the bottom surface of the groove to prevent vapor phase growth from the bottom surface;
In the step of vapor-phase growing the -V group compound semiconductor layer, vapor-phase growth is performed on the substrate except for the bottom surface of the groove.

In the method of growing a semiconductor layer according to the present invention, preferably, after the step of forming the groove, the semiconductor substrate is grown on the substrate.
Before the step of vapor-phase growing an IV compound semiconductor layer,
Forming a mask layer on the surface of the substrate excluding the region where the groove is formed to prevent vapor growth from the surface of the substrate; and forming a group III-V compound semiconductor layer on the substrate by vapor phase growth. In the step of performing the vapor deposition, vapor-phase growth is performed on the substrate in a region where the groove is formed.

In the method for growing a semiconductor layer according to the present invention, preferably, after the step of forming the groove, the semiconductor layer is formed on the substrate.
Before the step of vapor-phase growing an IV compound semiconductor layer,
A step of forming a mask layer on the surface of the substrate and the bottom surface of the groove excluding the formation region of the groove to prevent vapor phase growth from the surface and the bottom surface of the substrate; In the step of vapor-phase growing the group V compound semiconductor layer, vapor-phase growth is performed on the inner surface of the groove.

In the method of growing a semiconductor layer according to the present invention, preferably, the III-V compound semiconductor substrate is a GaN substrate, and the III-V compound semiconductor layer is a GaN layer. More preferably, in the step of forming the groove, the <1-100> direction of the substrate or the <11-2>
0> direction.

The method for growing a semiconductor layer according to the present invention described above includes the method of
a III-V compound semiconductor substrate, such as an aN substrate, having an inner surface that is substantially perpendicular to the main surface of the substrate;
A groove extending in a predetermined direction such as the 0> direction or the <11-20> direction is formed. Then, the growth rate in the direction perpendicular to the main surface of the substrate is more reduced in the direction within the main surface of the substrate. Under a condition of a high growth rate, a III-V compound semiconductor layer such as a GaN layer is vapor-phase grown on the substrate in which the groove is formed.
Since the growth rate in the lateral direction from the inner surface of the groove is high, the direction of the threading dislocation is changed and converged, so that a high-quality crystal region with few threading dislocations is grown in a region other than the region where the threading dislocation has converged. Can be done.

Before the vapor phase growth, the bottom of the groove,
By forming a mask layer for preventing vapor phase growth on the surface of the substrate excluding the region where the groove is formed, growth from the bottom surface of the groove and the surface of the substrate excluding the region where the groove is formed can be prevented. In addition, since it is possible to prevent the threading transition from being inherited from the surface of the substrate excluding the groove forming region, it is possible to grow a high-quality crystal region with a smaller threading transition.

In order to achieve the above object, a semiconductor light emitting device of the present invention comprises a III-V compound semiconductor substrate, a first cladding layer of at least a first conductivity type formed on the substrate, An active layer, and a semiconductor laminate including a laminate of a second cladding layer of a second conductivity type, wherein the substrate has an inner side surface that is substantially perpendicular to the main surface, and is provided in a predetermined direction. An extending groove is formed, and I is in contact with the substrate.
The II-V compound semiconductor layer is a layer which is vapor-phase grown so as to fill the above-mentioned groove.

Preferably, in the semiconductor light emitting device of the present invention, a mask layer for preventing vapor phase growth from the bottom surface is formed on the bottom surface of the groove.

Preferably, in the semiconductor light emitting device of the present invention described above, a mask layer for preventing vapor phase growth from the surface of the substrate is formed on the surface of the substrate except for the region where the groove is formed.

In the semiconductor light emitting device of the present invention, preferably, the vapor phase growth from the surface of the substrate and the bottom surface of the groove is prevented on the surface of the substrate and the bottom surface of the groove except for the region where the groove is formed. A mask layer is formed.

In the above-described semiconductor light emitting device of the present invention, preferably, the III-V compound semiconductor substrate is a GaN substrate, and the III-V compound semiconductor layer is a GaN layer. More preferably, the groove is <1-10 of the substrate.
0> direction or <11-20> direction.

In the semiconductor light emitting device of the present invention, a semiconductor laminate including at least a first conductive type first clad layer, an active layer, and a second conductive type second clad layer is formed. A III-V compound semiconductor substrate such as a GaN substrate has an inner surface that is substantially perpendicular to the main surface, and <1-
A groove extending in a predetermined direction such as the <100> direction or the <11-20> direction is formed, and the groove in contact with the substrate is formed.
A III-V compound semiconductor layer such as an N layer is a layer which is vapor-phase grown so as to fill a groove. III above
In the group V compound semiconductor layer, it is possible to change the direction of the threading transition inherited from the substrate and converge it, so that a region other than the area where the threading transition converges has a good crystal region with less threading transition. And the semiconductor light emitting device formed in this region has excellent characteristics.

In a structure in which a mask layer for preventing vapor phase growth is formed on the bottom surface of the groove or on the surface of the substrate except for the region where the groove is formed, the group III-V compound semiconductor layer is formed on the bottom surface of the groove,
Since the layer is prevented from growing from the surface of the substrate except for the region where the groove is formed, the layer is grown while preventing the transfer of threading transfer from the bottom surface of the groove and the surface of the substrate except for the region where the groove is formed. And a high-quality crystal region with less threading dislocation.

[0024]

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

First Embodiment A method for growing a semiconductor layer according to this embodiment will be described with reference to the drawings. In the present embodiment, G formed by HVPE (hydride vapor phase epitaxial growth) or the like is used.
A GaN layer is grown on the aN substrate by MOCVD. First, as shown in FIG. 1A, a PVD such as evaporation is formed on a GaN substrate 30 formed by the HVPE method or the like.
(Physical Vapor Deposition) method or CVD (Ch
emical Vapor Deposition) method, for example, 0.5μ
An m-th silicon oxide film 31 is formed. The above-described silicon oxide film is a layer that serves as an etching mask for forming a groove in the GaN substrate 30 and is used as a layer that prevents the growth of the GaN film from a region where the silicon oxide film is left. There is also. The thickness of the silicon oxide film can be set according to the etching selectivity when etching the GaN substrate in a later step. Further, in addition to silicon oxide, a material having a selectivity of etching with respect to a GaN substrate, such as silicon nitride, is used.
A material that prevents the growth of the aN film can be used.

Next, as shown in FIG. 1B, a resist film R1 having a pattern for opening a region where a groove is to be formed in the GaN substrate 30 in a later step is formed on the silicon oxide film 31 by a photolithography step. Form. Here, the formation direction of the groove is, for example, <1-100 of the GaN substrate 30.
> Direction or <11-20> direction. Next, the silicon oxide film 31 in a region where a groove opened in the resist film R1 is formed is removed by etching such as RIE (reactive ion etching) using a CF ₄ or CHF ₃ gas, and a mask layer is formed. 31a.

Next, as shown in FIG.
₂ After removing the resist film R1 by ashing,
Using the mask layer 31a as a mask, for example, etching such as RIE using a Cl ₂ or SiCl ₄ gas is performed to form a groove G in the GaN substrate 30. Under normal etching conditions, the inner surface of the groove G is formed substantially perpendicular to the main surface of the GaN substrate 30.

Next, as shown in FIG. 2B, the mask layer 31a is removed by HF wet etching. The groove G formed as described above is, for example, GaN
<1-100> direction of substrate 30 or <11-20>
The width W1 is, for example, 8 to 12 μm, and the depth d is, for example, 2 to 3 μm. Further, the distance between the grooves G (the width of the region where the surface of the GaN substrate 30 is left without forming the grooves) W
2 is, for example, 2 to 4 μm.

Next, as shown in FIG. 3, the growth rate in the direction perpendicular to the main surface of the GaN substrate 30 is smaller than that in the direction perpendicular to the main surface of the GaN substrate 30, for example, under a reduced pressure condition. Under a condition of a high growth rate, for example, a GaN layer 32 or the like as a III-V compound semiconductor layer is grown on the GaN substrate 30 in which the groove G is formed.

In FIG. 3, in the GaN layer 32, the growth layer surface S at each point during the growth is depicted. G
With the growth of the aN layer 32, the threading transition is inherited from the GaN substrate 30 in the GaN layer 32. However, under the condition that the growth rate of the GaN substrate 30 in the in-plane direction is faster than the growth rate in the direction perpendicular to the main surface of the GaN substrate 30, the growth in the in-principal direction proceeds. As a result, the through transition T inherited from the inner surface of the groove G and the bottom surface of the groove G which is substantially perpendicular to the main surface of the GaN substrate 30
Are bent in the GaN layer 32 to change the stretching direction.
For this reason, according to the semiconductor layer growth method of the present embodiment,
The threading transition T converges to a certain region on the surface of the GaN layer 32 to be formed, and a high-quality crystal region having a small threading transition T can be grown in the region X excluding the region where the threading transition T converges.

Second Embodiment A method for growing a semiconductor layer according to the present embodiment is different from the method shown in FIG. 2A described in the first embodiment in that the growth of the GaN substrate 30 is performed under reduced pressure conditions. Under the condition that the growth rate in the in-plane direction of the GaN substrate 30 is higher than the growth rate in the direction perpendicular to the plane, the III-V compound semiconductor layer is formed on the GaN substrate 30 in which the groove G is formed. As a method, for example, a GaN layer 32 or the like is vapor-phase grown. As a result, the structure shown in FIG. 4 is obtained.

In FIG. 4, the growth layer surface S at each point during the growth is depicted in the GaN layer 32. G
With the growth of the aN layer 32, the threading transition is inherited from the GaN substrate 30 in the GaN layer 32. However, under the condition that the growth rate of the GaN substrate 30 in the in-plane direction is faster than the growth rate in the direction perpendicular to the main surface of the GaN substrate 30, the growth in the in-principal direction proceeds. As a result, the through transition T inherited from the inner surface of the groove G and the bottom surface of the groove G which is substantially perpendicular to the main surface of the GaN substrate 30
Are bent in the GaN layer 32 to change the stretching direction.
For this reason, according to the semiconductor layer growth method of the present embodiment,
The threading transition T converges to a certain region on the surface of the GaN layer 32 to be formed, and a high-quality crystal region having a small threading transition T can be grown in the region X excluding the region where the threading transition T converges.

The GaN substrate 3 excluding the region where the groove G is formed
0, a mask layer 31a used as an etching mask for forming the groove G is left. Since the mask layer 31a has a function of preventing vapor phase growth, the surface of the GaN substrate 30 excluding the region where the groove G is formed is formed. From the surface of the GaN substrate 30 excluding the region where the groove G is formed. Therefore, according to the method for growing a semiconductor layer of the present embodiment, a high-quality crystal region with less threading transition can be grown.

Third Embodiment A method for growing a semiconductor layer according to this embodiment will be described with reference to the drawings. The process up to the structure shown in FIG. 2B is performed in the same manner as in the first embodiment. Next, as shown in FIG.
On the entire surface of the GaN substrate 30 including the inner side surface and the bottom surface of the groove G, for example, a silicon oxide film 33 is formed by a PVD method such as vapor deposition or a CVD method. In the case of vapor deposition, the conditions can be, for example, a growth temperature of 150 ° C. and a growth rate of about 0.3 nm / min.

In the above-described step of forming the silicon oxide film 33, a plane parallel to the main surface of the GaN substrate 30 (the surface of the GaN substrate 30 excluding the region where the groove G is formed and the bottom surface of the groove G) according to the forming conditions. The upper part has higher quality (chemical stability) than the part on the plane perpendicular to the main surface of the GaN substrate 30 (the inner side surface of the groove G). A> b (for example, b) in the thickness a of the portion on a plane parallel to the
Is about 70% of a), and thus the silicon oxide film 33 can be formed.

Next, as shown in FIG. 5B, a portion of the silicon oxide film 33 on a surface perpendicular to the main surface of the GaN substrate 30 (the inner side surface of the groove G) is removed. The silicon oxide film is left on the plane parallel to the main surface (the surface of the GaN substrate 30 excluding the region where the groove G is formed and the bottom surface of the groove G) to form a mask layer (33a, 33b). The removal of the silicon oxide film 33 on the surface perpendicular to the main surface of the GaN substrate 30 (the inner side surface of the groove G) is performed, for example, by using a KOH solution (3% by weight, 60%
C.) for 5 minutes.

Next, as shown in FIG. 6, the growth rate in the direction perpendicular to the main surface of the GaN substrate 30 is smaller than that in the direction perpendicular to the main surface of the GaN substrate 30, for example, under a reduced pressure condition. Under a condition of a high growth rate, for example, a GaN layer 32 or the like as a III-V compound semiconductor layer is grown on the GaN substrate 30 in which the groove G is formed. In the above,
Since the mask layer (33a, 33b) is formed on the surface of the GaN substrate 30 excluding the bottom surface of the groove and the region where the groove G is formed, the vapor phase growth from this surface is prevented. It grows only from the side.

FIG. 6 shows a growth layer surface S at each point during the growth in the GaN layer 32. G
With the growth of the aN layer 32, the threading transition is inherited from the GaN substrate 30 in the GaN layer 32. However, under the condition that the growth rate of the GaN substrate 30 in the in-plane direction is faster than the growth rate in the direction perpendicular to the main surface of the GaN substrate 30, the growth in the in-principal direction proceeds. As a result, the through transition T inherited from the inner surface of the groove G substantially perpendicular to the main surface of the GaN substrate 30
2 and the stretching direction is changed. For this reason, according to the semiconductor layer growth method of the present embodiment, the Ga
The threading transition T converges to a certain region on the surface of the N layer 32, and a high-quality crystal region having a small threading transition T can be grown in a region X excluding the region where the threading transition T converges.

On the surface of the GaN substrate 30 excluding the bottom surface of the groove and the region where the groove G is formed, a mask layer (33a, 33
Since b) is formed, inheritance of threading dislocation from this plane can be prevented, and a high-quality crystal region with less threading dislocation can be grown.

Fourth Embodiment A method for growing a semiconductor layer according to this embodiment will be described with reference to the drawings. The process up to the structure shown in FIG. 5B is performed in the same manner as in the first embodiment and the third embodiment. Next, FIG.
As shown in (a), a photoresist film R2 is applied over the entire surface to form a film. At this time, with respect to the depth d of the groove G, application is performed so that the thickness D of the photoresist film formed when applied on a flat substrate is D <d. For example,
When d = 2 μm and D = 0.8 μm, the thickness d ′ of the resist film R2 on the mask layer 33a on the surface of the GaN substrate 30 excluding the region where the groove G is formed is sufficiently larger than the depth d of the groove G. It can be small, for example, d ′ = 0.1 to 0.2 μm.

Next, as shown in FIG.
A part of the resist film R2 is removed by an etching process E such as RIE using ₂ . At this time, the mask layer 33
The resist layer R2 on the mask layer 3 is completely removed.
3a, while the mask layer 33b on the bottom of the groove G is exposed.
An etching process is performed so that the upper resist film R2 can be left.

Next, as shown in FIG.
The mask layer 33 on the surface of the GaN substrate 30 excluding the region where the groove G is to be formed by F-based wet etching or etching such as RIE using a CF ₄ -based gas.
a is removed. At this time, the mask layer 33 on the bottom surface of the groove G
b is not removed because it is protected by the resist film R2.

Next, as shown in FIG.
_{(2) The} resist film R2 is removed by ashing.

Next, as shown in FIG. 9, for example, the growth rate in the direction perpendicular to the main surface of the GaN substrate 30 is smaller in the direction in the main surface of the GaN substrate 30 than in the growth under reduced pressure conditions. Under a condition of a high growth rate, for example, a GaN layer 32 or the like as a III-V compound semiconductor layer is grown on the GaN substrate 30 in which the groove G is formed. In the above,
Since the mask layer 33b is formed on the bottom surface of the groove, vapor phase growth from this surface is prevented, and the GaN layer is grown from the inner surface of the groove G and the surface of the GaN substrate 30 excluding the region where the groove G is formed. become.

In FIG. 9, the growth layer surface S at each point during the growth is depicted in the GaN layer 32. G
With the growth of the aN layer 32, the threading transition is inherited from the GaN substrate 30 in the GaN layer 32. However, under the condition that the growth rate of the GaN substrate 30 in the in-plane direction is faster than the growth rate in the direction perpendicular to the main surface of the GaN substrate 30, the growth in the in-principal direction proceeds. As a result, the through transition T inherited from the inner surface of the groove G substantially perpendicular to the main surface of the GaN substrate 30
2 and the stretching direction is changed. For this reason, according to the semiconductor layer growth method of the present embodiment, the Ga
The threading transition T converges to a certain region on the surface of the N layer 32, and a high-quality crystal region having a small threading transition T can be grown in a region X excluding the region where the threading transition T converges.

Further, since the mask layer 33b is formed on the surface of the bottom surface of the groove, it is possible to prevent the transfer of threading dislocation from this surface, and to grow a high-quality crystal region with less threading dislocation.

Fifth Embodiment FIG. 1 is a perspective view of a GaN-based semiconductor light emitting device (laser diode LD) which is a nitride III-V compound semiconductor light emitting device according to the present embodiment. A GaN-based semiconductor layer including an active layer 16 having a multiple quantum well structure is stacked on a GaN substrate 11 to form a semiconductor stacked body 10. In the semiconductor laminate 10, the p-type electrode 10a and the n-type electrode 1 are connected to the p-type clad layer and the n-type clad layer formed so as to sandwich the active layer 16, respectively.
0b are respectively formed. When a predetermined voltage is applied from the power supply B to the p-electrode 10a and the n-electrode 10b, the laser light L is emitted from the active layer 16 in the semiconductor laminate 10.

FIG. 11A 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 GaN substrate 11, and an n-type GaN layer (contact layer) 13 having a thickness of about 5.0 μm, about 0.5 μm N-type AlGaN layer (cladding layer) 14 having a thickness of about 0.1 μm and n-type Ga
An N layer (guide layer) 15, an active layer (light emitting layer) 16 having a multiple quantum well (MQW) structure made of GaInN or the like;
P-type AlGaN layer (cap layer) 1 having a thickness of 02 μm
7. A p-type GaN layer (guide layer) having a thickness of about 0.1 μm
18, a p-type AlGaN layer (cladding layer) 19 having a thickness of about 0.5 μm, and a p-type GaN layer (contact layer) 20 having a thickness of about 0.1 μm. In the above description, silicon (Si) or the like is used as the n-type impurity (donor impurity) doped into the n-type layer, and magnesium (Mg) or zinc (zinc) is used as the p-type impurity (acceptor impurity) doped into the p-type layer. Zn) or the like.

In the semiconductor laminate 10 described above, GaN
The buffer layer 12 made of GaN on the substrate 11 is a layer grown according to the first to fourth embodiments. That is, G
The inner surface of the aN substrate 11 is substantially perpendicular to the GaN substrate 30 and has a <1-100> direction or a <11-20> direction.
A groove (not shown) extending in the> direction is formed. The width of the groove is, for example, 8 to 12 μm, the interval between the grooves is 2 to 4 μm, and the width of the semiconductor laminate 10 is several hundred μm.
For example, about 10 to 30 grooves are formed side by side. GaN substrate 11 having the above groove formed
The growth rate in the direction perpendicular to the main surface of the GaN substrate 30 is reduced by MOCVD or the like.
The buffer layer 12 made of GaN is formed under the condition that the growth rate in the main surface direction is high. Therefore, as described in the first to fourth embodiments, the buffer layer 12 has a region with a small threading transition, and the light emitting element in which the light emitting region is arranged in the region with a small threading transition can provide a device characteristic. Can be improved.

FIG. 10B is a schematic diagram showing the potential of the active layer 16 having the multiple quantum well structure. In the active layer 16, the content of indium (In) is 2%.
And 8% of layers are alternately stacked, and the potential of each layer is different, so that a multiple quantum well structure is formed.

A method for manufacturing the GaN-based semiconductor light emitting device (laser diode LD) will be described. First, as shown in FIG. 12A, a groove (not shown) is formed in the GaN substrate 11 using the semiconductor layer growth method according to the first to fourth embodiments, and Ga is formed on the upper surface thereof by MOCVD or the like.
A buffer layer 12 is formed by growing an N layer. The buffer layer 12 having a region with little threading dislocation can be grown by the semiconductor layer growth method according to the first to fourth embodiments. Next, the buffer layer 12 is formed by MOCVD or the like.
An n-type GaN layer (contact layer) 13 having a thickness of about 5.0 μm and an n-type AlGa layer having a thickness of about 0.5 μm
An N layer (cladding layer) 14 and an n-type GaN layer (guide layer) 15 having a thickness of about 0.1 μm are formed by sequentially growing crystals. In the above, n doped into each of the n-type layers
Silicon (Si) or the like is used as the type impurity (donor impurity).

Next, as shown in FIG. 12B, GaIn is formed on the n-type GaN layer 15 by MOCVD, for example.
An active layer (light emitting layer) 16 having a multiple quantum well (MQW) structure made of N is formed by crystal growth.

Next, a p-type A layer having a thickness of 0.01 to 0.5 μm is formed on the active layer 16 by MOCVD, for example.
An lGaN layer (cap layer) 17, a p-type GaN layer (guide layer) 18 having a thickness of about 0.1 μm, a p-type AlGaN layer (cladding layer) 19 having a thickness of about 0.5 μm, and about 0 μm. .1 μm-thick p-type GaN layer (contact layer) 2
0 are formed by crystal growth in order, leading to the structure shown in FIG. In the above, magnesium (M) is used as a p-type impurity (acceptor impurity) doped into each p-type layer.
g) or zinc (Zn). In the subsequent steps, a desired laser diode can be obtained by forming the electrodes (10a, 10b) and forming the end faces of the laser resonator by etching or cleavage.

Using the laser diode according to the present embodiment, a laser coupler mounted on an optical pickup device for an optical disk device can be preferably configured.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to these embodiments. For example, as a method of growing a semiconductor layer, GaN
Not limited to the growth of a GaN layer on a substrate, but other III-
Other group III-V compound semiconductor layers can be grown on the group V compound semiconductor substrate. The emission wavelength of the laser diode or other light emitting element of 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). 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.

[0056]

According to the method for growing a semiconductor layer of the present invention,
By changing and converging the direction of the threading transition inherited from the substrate, it is possible to grow a high-quality crystal region with a small threading transition in a region other than the region where the threading transition has converged.

According to the semiconductor light emitting device of the present invention,
Since it is possible to change the direction of the threading transition inherited from the substrate and make it converge, a region other than the area where the threading transition converges has a high-quality crystal region with few threading transitions. The semiconductor light emitting device formed in the above has excellent characteristics.

[Brief description of the drawings]

FIGS. 1A and 1B are cross-sectional views illustrating a method for growing a semiconductor layer according to the present invention, in which FIG. 1A illustrates up to a step of forming a silicon oxide layer, and FIG.

FIG. 2 is a sectional view showing a step subsequent to that of FIG. 1;
(A) shows up to the step of forming a groove, and (b) shows up to the step of removing the mask layer.

FIG. 3 is a schematic cross-sectional view showing a semiconductor layer grown by the method for growing a semiconductor layer according to the first embodiment.

FIG. 4 is a schematic cross-sectional view showing a semiconductor layer grown by a method for growing a semiconductor layer according to a second embodiment.

FIG. 5 is a sectional view showing a step continued from FIG. 2;
(A) shows up to the step of forming a silicon oxide layer, and (b) shows up to the step of forming a mask layer.

FIG. 6 is a schematic cross-sectional view showing a semiconductor layer grown by a method for growing a semiconductor layer according to a third embodiment.

FIG. 7 is a sectional view showing a step subsequent to that of FIG. 5;
(A) shows up to the step of forming a resist film, and (b) shows up to the step of etching the resist film.

FIG. 8 is a sectional view showing a step subsequent to that of FIG. 7;
(A) shows up to the step of removing the mask layer exposed from the resist film, and (b) shows the step up to the step of removing the resist film.

FIG. 9 is a schematic cross-sectional view showing a semiconductor layer grown by a method for growing a semiconductor layer according to a fourth embodiment.

FIG. 10 is a perspective view of a semiconductor light emitting device (laser diode) according to the present invention and a conventional example.

11A is a cross-sectional view of a semiconductor laminate portion of the semiconductor light emitting device shown in FIG. 10, and FIG. 11B is a potential diagram of an active layer.

12A and 12B are cross-sectional views illustrating a manufacturing process of the method for manufacturing the semiconductor light emitting device shown in FIG. 11, in which FIG. 12A is a process up to a process of forming a lower layer of an active layer, and FIG. Up to

FIG. 13 is a perspective view of a semiconductor light emitting device (laser diode) according to a conventional example.

[Explanation of symbols]

Reference numeral 10: semiconductor laminate, 10a: p electrode, 10b: n electrode, 10c: lead portion, 11: GaN substrate, 11 '...
Sapphire substrate, 12: buffer layer, 13: n-type GaN
Layers (contact layer), 14 ... n-type AlGaN layer (cladding layer), 15 ... n-type GaN layer (guide layer), 16 ... active layer (light-emitting layer), 17 ... p-type AlGaN layer (cap layer), 18 ... p-type GaN layer (guide layer), 19 ... p-type A
lGaN layer (cladding layer), 20: p-type GaN layer (contact layer), 30: GaN substrate, 31, 33: silicon oxide film, 31a, 33a, 33b: mask layer, 32: G
aN layer, B: power supply, E: etching, G: groove, L: laser beam, LD, LD ': laser diode, R1, R2 ...
Resist film, S: growth layer surface, T: penetration transition.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Satoru Kishima 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F-term (reference) 5F041 AA40 CA05 CA33 CA34 CA40 CA65 CA74 CA75 5F045 AA04 AB14 AF04 AF12 AF13 BB12 CA10 DA55 DB02 DB04 5F073 AA74 CA07 CB02 CB07 DA05 DA07 DA25

Claims (12)

[Claims] A step of forming a groove in a group III-V compound substrate having an inner surface substantially perpendicular to the main surface of the substrate and extending in a predetermined direction; Under the condition that the growth rate in the in-plane direction of the substrate is faster than the growth rate in the direction perpendicular to the direction, the group III-V compound semiconductor layer is vapor-phase grown on the substrate in which the groove is formed. And growing the semiconductor layer. 2. The method according to claim 1, wherein after the step of forming the groove, before the step of vapor-phase growing the III-V compound semiconductor layer on the substrate, the vapor-phase growth from the bottom of the groove is prevented. The method according to claim 1, further comprising a step of forming a mask layer, wherein in the step of vapor-phase growing the III-V compound semiconductor layer on the substrate, the vapor-phase growth is performed on the substrate except for a bottom surface of the groove. A method for growing a semiconductor layer. 3. After the step of forming the groove, before the step of vapor-phase growing a group III-V compound semiconductor layer on the substrate, the surface of the substrate except for a region where the groove is formed is formed on the surface of the substrate. A step of forming a mask layer for preventing vapor phase growth from the surface; and a step of vapor-phase growing the group III-V compound semiconductor layer on the substrate. 2. The method for growing a semiconductor layer according to claim 1, wherein the semiconductor layer is grown by vapor phase. 4. The method according to claim 1, wherein after the step of forming the groove, before the step of vapor-phase growing a group III-V compound semiconductor layer on the substrate, the surface of the substrate excluding a region where the groove is to be formed and the groove. A step of forming a mask layer on the bottom surface for preventing vapor phase growth from the surface of the substrate and the bottom surface, wherein the step of vapor-phase growing a group III-V compound semiconductor layer on the substrate comprises: 2. The method for growing a semiconductor layer according to claim 1, wherein the semiconductor layer is grown on the inner surface of the groove by vapor phase growth. 5. The method according to claim 1, wherein the III-V compound semiconductor substrate is Ga.
The method for growing a semiconductor layer according to claim 1, wherein the substrate is an N substrate, and the III-V compound semiconductor layer is a GaN layer. 6. The method of growing a semiconductor layer according to claim 5, wherein, in the step of forming the groove, the groove is formed in a <1-100> direction or a <11-20> direction of the substrate. 7. A III-V compound semiconductor substrate, and at least a first conductive type first semiconductor substrate formed on the substrate.
A clad layer, an active layer, and a semiconductor laminate including a laminate of a second clad layer of the second conductivity type; the substrate has an inner surface that is substantially perpendicular to the main surface; A semiconductor light emitting device, wherein a groove extending in a predetermined direction is formed, and the group III-V compound semiconductor layer in contact with the substrate is a layer grown by vapor phase so as to fill the groove. 8. The semiconductor light emitting device according to claim 7, wherein a mask layer for preventing a vapor phase growth from said bottom surface is formed on a bottom surface of said groove. 9. The semiconductor light emitting device according to claim 7, wherein a mask layer for preventing a vapor phase growth from the surface of the substrate is formed on a surface of the substrate except for a region where the groove is formed. 10. The mask layer according to claim 7, wherein a mask layer for preventing a vapor phase growth from the substrate surface and the bottom surface is formed on the surface of the substrate and the bottom surface of the groove except for the region where the groove is formed. Semiconductor light emitting device. 11. The method according to claim 11, wherein the III-V compound semiconductor substrate is G
The semiconductor light emitting device according to claim 7, wherein the semiconductor light emitting device is an aN substrate, and the III-V compound semiconductor layer is a GaN layer. 12. The semiconductor light emitting device according to claim 11, wherein said groove is formed in a <1-100> direction or a <11-20> direction of said substrate.