JP2003046195A - Nitride-based semiconductor light emitting element and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nitride-based semiconductor light emitting element that can stabilize shut-out of light in the horizontal direction. SOLUTION: This nitride-based semiconductor light emitting element is provided with an MQW light emitting layer 8, a p-type second clad layer 10 that is formed on the MQW light emitting layer 8 and is made of p-type AlGaN and constitutes a current passage, and a current block layer 14 that is formed as cover the sides of the current passage and is made of Si doped GaInN. The current block layer 14 is formed adjacent to the current passage, and an area excluding the vicinity of the current passage includes areas where the current block layer 14 is not formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitride semiconductor light emitting device and a manufacturing method thereof, and more particularly to a nitride semiconductor light emitting device having a current blocking layer and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, a nitride-based semiconductor laser device, which is one of nitride-based semiconductor light-emitting devices, is expected to be used as a light source for a next-generation large-capacity disk. It is being appreciated. In a conventional nitride-based semiconductor laser device, a structure in which a current block layer made of a material having a conductivity opposite to that of the nitride-based semiconductor layer forming the ridge is provided on the side of the ridge that serves as a current passage part. Are known to have. A nitride-based semiconductor laser device having such a structure is disclosed in, for example, Japanese Patent Laid-Open No. 10-321962.
It is disclosed in the publication.

As an example of the structure of a nitride-based semiconductor laser device having the ridge portion and the current blocking layer as described above, an n-type nitride-based semiconductor layer and a light emitting layer are formed on a substrate. A p-type cladding layer having a convex portion (ridge portion) is formed on the light emitting layer. Then, an n-type clad layer having a conductivity opposite to that of the p-type clad layer is formed so as to cover the side part of the ridge part serving as a current passage part and the entire flat part other than the ridge part on the upper surface of the p-type clad layer. A current blocking layer made of a material is formed.

In the conventional nitride semiconductor laser device described above, the current blocking layer is formed using a material having a refractive index different from that of the p-type cladding layer, so that the light-emitting layer below the p-type cladding layer and the current An effective refractive index difference can be generated between the light emitting layer below the block layer. By utilizing this difference in refractive index, it is possible to confine lateral light in the light emitting layer.

In this case, in order to strengthen the confinement of the laser light in the light emitting layer or to obtain a good vertical far-field image, the p-type cladding layer on the light emitting layer and the current blocking layer are refracted. It is necessary to increase the rate difference. in this way,
In order to increase the refractive index difference, a method of increasing the Al composition of the current blocking layer made of AlGaN, or GaIn
There is a method of increasing the In composition of the current blocking layer made of N.

By constructing the current blocking layer using a material having a refractive index smaller than that of the material of the p-type cladding layer, an effective refractive index difference can be formed in the light emitting layer. For example, when the p-type cladding layer and the current blocking layer are formed of AlGaN, the Al composition of AlGaN forming the current blocking layer is made larger than the Al composition of AlGaN forming the p-type cladding layer, Light can be confined laterally in the light emitting layer. The nitride-based semiconductor laser device having such a structure is generally called a real index guided laser.

Further, the current blocking layer can be made of a material having a band gap smaller than that of the light emitting layer. For example, when the light emitting layer and the current blocking layer are formed using InGaN, and the In composition of InGaN forming the current blocking layer is made larger than the In composition of InGaN forming the light emitting layer, the light emitting layer and the current blocking layer are generated in the light emitting layer. Part of the generated light can be absorbed by the current blocking layer. This allows light to be confined laterally. The nitride semiconductor laser device having such a structure is generally called a complex index guided laser.

[0008]

In the conventional real index waveguide type laser described above, the current block layer is formed above the substrate or the nitride-based semiconductor layer having a large thickness on the substrate. In this case, when GaN is used as the substrate or the nitride-based semiconductor layer having a large thickness on the substrate, the lattice constant of AlGaN forming the current block layer is smaller than the lattice constant of GaN. When the Al composition of the layer is increased, strain is applied to the current blocking layer. Therefore, there is a disadvantage that cracks and lattice defects are likely to occur in the current blocking layer. as a result,
Since it is difficult to form the current blocking layer thick, it is difficult to stabilize the optical confinement in the lateral direction.

Also in the above-described conventional complex index guided laser, the current block layer is formed above the substrate or the thick nitride semiconductor layer on the substrate, as in the conventional real index laser. Has been done. In this case, as the substrate or the nitride-based semiconductor layer having a large thickness on the substrate, Ga
When N is used, the lattice constant of InGaN forming the current blocking layer is larger than that of GaN, so that I
When the In composition of the current blocking layer made of nGaN is increased, strain is applied to the current blocking layer. For this reason, there arises a disadvantage that lattice defects are likely to occur in the current blocking layer. Also in this case, it is difficult to form the current blocking layer thickly, and it is difficult to stabilize the optical confinement in the lateral direction.

The present invention has been made to solve the above problems, and one object of the present invention is to:
It is an object of the present invention to provide a nitride-based semiconductor light emitting device capable of stabilizing lateral light confinement.

Another object of the present invention is to provide a method for manufacturing a nitride-based semiconductor light-emitting device capable of easily forming a nitride-based semiconductor light-emitting device capable of stabilizing optical confinement in the lateral direction. Is to provide.

[0012]

In order to achieve the above object, a nitride semiconductor light emitting device according to a first aspect of the present invention includes a light emitting layer and a first nitride semiconductor formed on the light emitting layer. And a clad layer including a current passage portion, and a current block layer formed to cover a side surface of the current passage portion and formed of a second nitride-based semiconductor, in a region other than the vicinity of the current passage portion, It includes a region where the current blocking layer is not formed. For example, it may include a region where the current blocking layer is not formed on the light emitting layer.

In the nitride-based semiconductor light emitting device according to the first aspect, the current blocking layer is configured so as to include a region where the current blocking layer is not formed in a region other than the vicinity of the current passage portion. The width of the current block layer is smaller than that in the case where it is formed on the entire surface other than the vicinity of the portion. Thereby, the strain applied to the current block layer due to the difference in lattice constant between the current block layer and the nitride semiconductor substrate or the nitride semiconductor layer formed on the substrate can be relaxed, so that the current It is possible to suppress the occurrence of cracks and lattice defects in the block layer. As a result, the thickness of the current blocking layer can be increased, so that lateral optical confinement can be stabilized.

In the nitride semiconductor light emitting device according to the first aspect, preferably, the current block layer is formed only near the current passage portion. According to this structure, the width of the current block layer is reduced, so that the strain applied to the current block layer can be further relaxed.

In the above nitride semiconductor light emitting device,
The total width of the current passage portion and the current block layer is preferably 3 times or more and 7 times or less the width of the current passage portion. That is, when the total width of the current passage portion and the current block layer is smaller than three times the width of the current passage portion, the formation range of the current block layer becomes too small, so that optical confinement in the lateral direction becomes insufficient. . Further, when the total width of the current passage portion and the current block layer is larger than 7 times the width of the current passage portion, the strain applied to the current block layer increases, so that many crystal defects occur in the current block layer. , Cracks easily occur. Therefore, the total width of the current passage portion and the current block layer is preferably 3 times or more and 7 times or less the width of the current passage portion.

Further, the above nitride-based semiconductor light emitting device preferably further comprises a mask layer formed on the clad layer at a predetermined distance from the current passage portion for selectively growing the current blocking layer. According to this structure, the current blocking layer can be selectively grown using the mask layer, so that the crystallinity of the current blocking layer can be improved. In this case, the mask layer is formed so as to be separated from the current passage portion by a distance of 1 to 3 times the width of the current passage portion. According to this structure, since the current block layer can be selectively grown only in the vicinity of the current passage portion using the mask layer as a mask, the strain applied to the current block layer can be easily relaxed. In this case, the mask layer preferably contains an oxide film or a nitride film containing at least one element selected from the group consisting of Si, Ti and Zr.

In the above nitride-based semiconductor light emitting device, preferably, the cladding layer includes a convex portion forming a current passage portion and a flat portion, and the current block layer is on a side surface of the convex portion and flat. It is formed on the part. According to this structure, it is possible to easily obtain a ridge-type semiconductor light emitting device including a current block layer in which the occurrence of cracks is suppressed. In this case, the mask layer is formed on the flat portion of the cladding layer, and the current blocking layer is formed on the side surface of the convex portion of the cladding layer, on the flat portion of the cladding layer, and on the mask layer. Good.

In the above nitride-based semiconductor light emitting device, preferably, the current blocking layer includes an opening,
The cladding layer includes a first cladding layer having a substantially flat upper surface and a second cladding layer formed on the first cladding layer in the opening and having a current passage portion. According to this structure, it is possible to easily obtain the self-aligned semiconductor light emitting device including the current block layer in which the generation of cracks is suppressed.

A nitride-based semiconductor light-emitting device according to a second aspect of the present invention includes a light-emitting layer, a first nitride-based semiconductor formed on the light-emitting layer, a clad layer including a current passage portion, and a current layer. A current blocking layer formed to cover the side surface of the passage portion and made of a second nitride-based semiconductor, wherein the current blocking layer is provided in a region other than the vicinity of the current passage portion, and has a thickness greater than that in the vicinity of the current passage portion. Includes a region of small thickness.

In the nitride-based semiconductor light-emitting device according to the second aspect, the current blocking layer is configured to include a region having a thickness smaller than the thickness in the vicinity of the current passage portion in a region other than the vicinity of the current passage portion. By doing so, the strain applied to the current block layer due to the difference in lattice constant between the current block layer and the nitride-based semiconductor substrate or the nitride-based semiconductor layer formed on the substrate is reduced by the thickness of the current block layer. It is easy to concentrate on a small area. As a result, crystal defects and cracks are likely to occur in regions of the current block layer having a small thickness other than in the vicinity of the current passage portion, so that cracks and lattice defects are generated in the current block layer near the current passage portion. Can be suppressed. As a result, the thickness of the current blocking layer in the vicinity of the current passage portion can be increased, so that lateral optical confinement can be stabilized.

In the nitride semiconductor light emitting device according to the second aspect, preferably, a step portion formed in a region other than the vicinity of the current passage portion is further provided, and the thickness is smaller than the thickness in the vicinity of the current passage portion. The region of the current block layer is formed in the step portion. With this configuration,
Since the current block layer can be selectively grown using the step portion, the crystallinity of the current block layer can be improved. Further, if the current block layer is selectively grown using the step portion, it is possible to easily form a region of the current block layer having a small thickness in the step portion. In this case, it is preferable that the step portion has a width of the current passage portion 1
It is formed at a position that is more than twice and less than three times.

In the nitride semiconductor light emitting device according to the first or second aspect, preferably, the current blocking layer contains at least one element selected from the group consisting of B, Ga, Al, In and Tl. N and.

In the nitride semiconductor light emitting device according to the first or second aspect, preferably, the current block layer includes an AlGaN layer, and the current block layer is G
The current blocking layer is formed on either the aN substrate or the GaN layer formed on the substrate.
It includes a second nitride-based semiconductor layer having a lattice constant smaller than N.
In this case, since the strain applied to the current block layer due to the difference in the lattice constant between the current block layer and GaN can be relaxed, it is possible to suppress the occurrence of cracks or lattice defects in the current block layer. . As a result, the lattice constant of the current blocking layer can be reduced, or the thickness of the current blocking layer can be increased, so that lateral optical confinement can be stabilized. For example, GaN
AlGa as a nitride semiconductor layer having a smaller lattice constant
The current blocking layer may include N. as a result,
Since the Al composition of AlGaN can be increased, the optical confinement in the lateral direction can be stabilized.

In the nitride-based semiconductor light emitting device according to the first or second aspect, preferably, the current blocking layer has a refractive index smaller than that of the first nitride-based semiconductor layer forming the cladding layer. A second nitride-based semiconductor layer having. In this case, the difference in refractive index between the clad layer and the current blocking layer can be increased, so that optical confinement in the lateral direction can be stabilized.

In the nitride-based semiconductor light emitting device according to the first or second aspect, preferably, the current block layer has a lattice constant smaller than that of the first nitride-based semiconductor layer forming the cladding layer. A second nitride-based semiconductor layer having. In this case, it is possible to suppress the occurrence of cracks and lattice defects in the current blocking layer. As a result, the current blocking layer having good crystallinity can be formed. Further, since the difference in lattice constant between the clad layer and the current blocking layer can be increased, lateral optical confinement can be stabilized.

In the nitride semiconductor light emitting device according to the first or second aspect, preferably, the current block layer includes an Al _x Ga _{1 -x} N layer and the cladding layer is A.
The current blocking layer and the cladding layer are formed so as to have a composition satisfying x> y, including the l _y Ga _{1 -y} N layer. In this case, it is possible to suppress the occurrence of cracks and lattice defects in the current blocking layer. As a result, the current blocking layer having good crystallinity can be formed. Further, since the difference in Al composition between the cladding layer and the current blocking layer can be increased, the difference in refractive index between the cladding layer and the current blocking layer can be increased. As a result, lateral optical confinement can be stabilized.

In the nitride semiconductor light emitting device according to the first or second aspect, preferably, the current block layer is a GaN substrate or a Ga formed on the substrate.
The current blocking layer formed on any one of the N layers includes a second nitride-based semiconductor layer having a lattice constant larger than that of GaN. In this case, since the strain applied to the current block layer due to the difference in the lattice constant between the current block layer and GaN can be relaxed, it is possible to suppress the occurrence of lattice defects in the current block layer.
As a result, the current blocking layer having good crystallinity can be formed. Further, since the lattice constant of the current blocking layer can be increased or the thickness of the current blocking layer can be increased, the lateral optical confinement can be stabilized. For example, the current blocking layer
G, which is a nitride-based semiconductor layer having a lattice constant smaller than that of GaN
You may form so that aInN may be included. In this case, Ga
Since the In composition of InN can be increased, lateral optical confinement can be stabilized.

In the nitride-based semiconductor light emitting device according to the first or second aspect, preferably, the current block layer includes a second nitride-based semiconductor layer that absorbs light emitted from the light emitting layer. In this case, more light generated in the light emitting layer can be absorbed in the current blocking layer.
As a result, the difference in refractive index between the clad layer and the current blocking layer can be increased, so that optical confinement in the lateral direction can be stabilized. For example, the current blocking layer may be formed to include the second nitride semiconductor layer having a smaller bandgap than the light emitting layer.

In the nitride semiconductor light emitting device according to the first or second aspect, preferably, the current block layer includes a Ga _1-x In _x N layer and the light emitting layer is a Ga layer.
_{The 1-y} In _y N layer is included, and the current blocking layer and the light emitting layer are
It is formed to have a composition satisfying x> y. In this case, it is possible to suppress the occurrence of lattice defects in the current blocking layer, so that the I
The difference in n composition can be increased. As a result, the current blocking layer having good crystallinity can be formed. Further, more light generated in the light emitting layer can be absorbed in the current blocking layer. As a result, the difference in refractive index between the cladding layer and the current blocking layer can be increased, so that optical confinement in the lateral direction can be stabilized.

A method of manufacturing a nitride-based semiconductor light-emitting device according to a third aspect of the present invention comprises a step of forming a clad layer made of a first nitride-based semiconductor on a light-emitting layer and including a current passage portion, A current blocking layer made of a second nitride semiconductor is formed near the current passage portion so as to cover the side surface of the current passage portion, and the current block layer is not formed in a region other than the vicinity of the current passage portion. And a step of forming a region.

In the method for manufacturing a nitride-based semiconductor light-emitting device according to the third aspect, as described above, the region where the current block layer is not formed is formed in the region other than the vicinity of the current passage portion. The width of the current block layer is smaller than that in the case where the current block layer is formed on the entire surface other than the vicinity of the current passage portion. Thereby, the strain applied to the current block layer due to the difference in lattice constant between the current block layer and the nitride semiconductor substrate or the nitride semiconductor layer formed on the substrate can be relaxed, so that the current It is possible to suppress the occurrence of cracks and lattice defects in the block layer. As a result, since the thickness of the current blocking layer can be increased, it is possible to easily form the nitride-based semiconductor light emitting device capable of stabilizing the optical confinement in the lateral direction.

In the method for manufacturing a nitride-based semiconductor light emitting device according to the third aspect, it is preferable that the method further comprises the step of forming a mask layer on the clad layer at a predetermined distance from the current passage portion. The step of forming the layer includes a step of selectively growing the current blocking layer using the mask layer to form the current blocking layer only in the vicinity of the current passage portion so as to cover the side surface of the current passage portion. According to this structure, the current blocking layer can be selectively grown using the mask layer, so that the crystallinity of the current blocking layer can be improved. Further, since the current blocking layer can be selectively grown only in the vicinity of the current passage portion using the mask layer as a mask, the strain applied to the current blocking layer can be easily relaxed.

A method of manufacturing a nitride-based semiconductor light-emitting device according to a fourth aspect of the present invention comprises a step of forming a clad layer made of a first nitride-based semiconductor on a light-emitting layer and including a current passage portion, Forming a current block layer made of a second nitride-based semiconductor that covers the side surface of the current passage portion and includes a region having a thickness smaller than the thickness in the vicinity of the current passage portion in a region other than the vicinity of the current passage portion. I have it.

In the method for manufacturing the nitride-based semiconductor light emitting device according to the fourth aspect, the region other than the vicinity of the current passage portion is
By forming a current block layer including a region having a thickness smaller than the thickness in the vicinity of the current passage portion, the lattice constant of the current block layer and the nitride-based semiconductor substrate or the nitride-based semiconductor layer formed on the substrate The strain applied to the current block layer due to the difference of 1 is likely to be concentrated in a region of the current block layer having a small thickness. As a result, crystal defects and cracks are likely to occur in regions of the current block layer having a small thickness other than in the vicinity of the current passage portion, so that cracks and lattice defects are generated in the current block layer near the current passage portion. Can be suppressed. As a result, the thickness of the current blocking layer in the vicinity of the current passage portion can be increased, so that a nitride-based semiconductor light emitting device capable of stabilizing lateral optical confinement can be easily formed.

In the method for manufacturing a nitride-based semiconductor light emitting device according to the fourth aspect, preferably, the step of forming the current block layer includes the step of forming a step portion in a region other than the vicinity of the current passage portion, and the step difference. Forming a region of the current block layer having a smaller thickness than the thickness of the current block layer in the vicinity of the current passage portion in the step portion by selectively growing the current block layer in the vicinity of the current passage portion using the portion. Including and According to this structure, since the current block layer can be selectively grown using the step portion, the crystallinity of the current block layer can be improved. Further, if the current block layer is selectively grown using the step portion,
It is possible to easily form the region of the current blocking layer having a small thickness in the step portion.

According to a fifth aspect of the present invention, a method for manufacturing a nitride-based semiconductor light-emitting device includes a step of forming a first cladding layer made of a first nitride-based semiconductor on a light-emitting layer, and a current passage portion. Forming a current blocking layer made of a second nitride-based semiconductor having an opening in the vicinity of the region to be formed, and forming a current passage portion on the first cladding layer in the opening of the current blocking layer. And a step of forming a second clad layer made of a nitride semiconductor.

In the method for manufacturing the nitride-based semiconductor light emitting device according to the fifth aspect, as described above, the current made of the second nitride-based semiconductor having the opening in the vicinity of the region where the current passage portion is formed is formed. After forming the block layer, the second clad layer made of the third nitride-based semiconductor forming the current passage part is formed on the first clad layer in the opening of the current block layer, so that the current can be easily formed. It is possible to form a self-aligned nitride-based semiconductor light emitting device in which the current block layer is formed only near the passage portion. As a result, the width of the current block layer becomes smaller than that in the case where the current block layer is formed on the entire surface other than the vicinity of the current passage portion. Therefore, the strain applied to the current block layer due to the difference in lattice constant between the current block layer and the nitride-based semiconductor substrate or the nitride-based semiconductor layer formed on the substrate can be relaxed. It is possible to suppress the occurrence of cracks and lattice defects in the block layer. as a result,
Since the thickness of the current blocking layer can be increased,
It is possible to easily form a self-aligned nitride-based semiconductor light-emitting device that can stabilize lateral optical confinement.

In the method for manufacturing a nitride semiconductor light emitting device according to the fifth aspect, preferably, a mask layer is formed on the first cladding layer at a predetermined distance from a region where the current passage portion is formed. The step of forming the current blocking layer further includes the step of selectively growing the current blocking layer using the mask layer to form the current blocking layer only in the vicinity of the region where the current passage portion is formed. including. According to this structure, using the mask layer,
Since the current blocking layer can be selectively grown, the crystallinity of the current blocking layer can be improved in the self-aligned nitride-based semiconductor light emitting device. Further, since the current block layer can be selectively grown only in the vicinity of the current passage portion using the mask layer as a mask, in the self-aligned nitride-based semiconductor light emitting device, strain applied to the current block layer can be easily relaxed. be able to.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a sectional view showing a nitride semiconductor laser device according to a first embodiment of the present invention. The structure of the nitride-based semiconductor laser device according to the first embodiment of the present invention will be described with reference to FIG. The nitride semiconductor laser device according to the first embodiment is a complex index guided laser device.

The structure of the nitride-based semiconductor laser device according to the first embodiment is as follows: sapphire (0001) plane substrate 1
(Hereinafter referred to as "sapphire substrate 1"), approximately 15n
A buffer layer 2 made of AlGaN having a thickness of m and an undoped GaN layer 3 having a thickness of about 0.5 μm are formed. On the undoped GaN layer 3, an n-type contact layer 4 made of n-type GaN having a mesa-shaped portion with a width of about 70 μm and a thickness of about 4 μm is formed. The sapphire substrate 1 is an example of the “substrate” in the present invention, and the n-type contact layer 4 is an example of the “nitride-based semiconductor layer” in the present invention.

On the upper surface of the mesa portion of the n-type contact layer 4, n-type Ga _0.95 In having a film thickness of about 0.1 μm is formed.
Crack prevention layer 5 made of _0.05 N, n-type second cladding layer 6 made of Si-doped Al _0.3 Ga _0.7 N having a thickness of about 1 μm, Si-doped GaN having a thickness of about 50 nm
An n-type first cladding layer 7 made of and an MQW light emitting layer 8 made of a GaInN multiple quantum well (MQW) are formed. The MQW light emitting layer 8 has a structure in which five undoped GaN barrier layers having a thickness of about 4 nm and four undoped Ga _0.85 In _0.15 N well layers having a thickness of about 4 nm are alternately stacked. The MQW light emitting layer is an example of the "light emitting layer" in the present invention.

A p-type first cladding layer 9 made of Mg-doped GaN having a film thickness of about 40 nm is formed on the MQW light emitting layer 8. On the upper surface of the p-type first cladding layer 9, M having a width of about 2 μm and a film thickness of about 0.45 μm.
p made of g-doped AlGaN (Al composition: 0.08)
The mold second clad layer 10 is formed. Further, a cap layer 11 made of p-type GaN having a film thickness of about 50 nm is formed so as to come into contact with almost the entire upper surface of the p-type second cladding layer 10. With the p-type second cladding layer 10 and the cap layer 11, the width W1 (first
In the embodiment, the current passage portion (ridge portion) 12 having a thickness of about 2 μm is formed. The p-type first cladding layer 9 and the p-type second cladding layer 10 are examples of the “cladding layer” in the present invention.

On the upper surface of the p-type first cladding layer 9, a mask layer 13 made of Si nitride such as Si ₃ N ₄ having an opening with a width of about 10 μm around the current passage portion 12 is formed. Has been done. The upper surface of the p-type first cladding layer 9 exposed in the opening of the mask layer 13 and a partial region on the upper surface of the mask layer 13 are filled with the side portions of the current passage portion 12 so as to be approximately A current blocking layer 14 made of Si-doped GaInN (In composition: 0.2) having a film thickness of 3 μm is formed. In this case, the current passage portion 12
And the total width W2 of the current blocking layer 14 (about 10 μm)
Is more than three times the width W1 (about 2 μm) of the current passage portion 7
It is set to a range equal to or less than twice (5 times in the first embodiment). This is for the following reason.

That is, when the total width W2 of the current passage portion 12 and the current block layer 14 is smaller than three times the width W1 of the current passage portion 12, the formation range of the current block layer 14 becomes too small. , Lateral light confinement becomes insufficient. The total width W2 of the current passage portion 12 and the current block layer 14 is 7 times the width W1 of the current passage portion 12.
When it is larger than twice, the strain applied to the current block layer 14 increases, and thus many lattice defects occur in the current block layer 14. Therefore, the total width W2 of the current passage portion 12 and the current block layer 14 is set to the width W of the current passage portion 12.
It is preferable to set the range of 3 times or more and 7 times or less.

On the current passage portion 12 and the current block layer 14, the current passage portion 12 (cap layer 11) is formed.
Covering almost the entire upper surface of the current block layer 1 and
3 μm to about 5 μm so as to cover a partial area on the upper surface of No. 4
A p-type contact layer 15 made of Mg-doped GaN having a film thickness of m is formed. In addition, each layer 2-11, 1
4 and 15 have a wurtzite structure and are formed by growing in the [0001] direction of a nitride semiconductor.

Au / Pd is formed on the p-type contact layer 15.
Is formed on the p-side electrode 16. An n-side electrode 17 made of Au / Ti is formed on the exposed surface of the n-type contact layer 4.

In the first embodiment, as described above, the current blocking layer 14 is provided with the width W2 (about 1) of the opening of the mask layer 13.
By forming it within the range of 0 μm), the current blocking layer 14 can be formed only in the vicinity of the current passage portion 12. As a result, the width of the current blocking layer 14 becomes smaller than that in the case where the current blocking layer 14 is formed in the vicinity of the current passage portion 12 and the entire surface other than the vicinity. As a result, the current block layer 14 is added to the current block layer 14 due to the difference in lattice constant between the current block layer 14 and the n-type contact layer 4 made of n-type GaN formed on the sapphire substrate 1 with a large thickness (about 4 μm). Since the strain can be relaxed, generation of lattice defects in the current blocking layer 14 can be suppressed. As a result, the thickness of the current blocking layer 14 can be increased, and the optical confinement in the lateral direction can be stabilized.

2 to 7 are sectional views for explaining the method for manufacturing the nitride-based semiconductor laser device according to the first embodiment of the present invention. With reference to FIG. 1 to FIG.
A method for manufacturing the nitride-based semiconductor laser device according to the embodiment will be described.

First, as shown in FIG. 2, MO under atmospheric pressure is used.
VPE method (Metal Organic Vapor)
Phase Epitaxy: metalorganic vapor phase epitaxy) and AlGa having a film thickness of about 15 nm on the sapphire substrate 1 while maintaining the substrate temperature at about 600 ° C.
A buffer layer 2 made of N is formed. Next, with the substrate temperature kept at about 1150 ° C., an n-type contact made of undoped GaN layer 3 having a thickness of about 0.5 μm and Si-doped GaN having a thickness of about 4 μm is formed on the buffer layer 2. Form layer 4. Furthermore, the substrate temperature is set to about 88.
With the temperature kept at 0 ° C., the crack prevention layer 5 made of n-type Ga _0.95 In _0.05 N having a film thickness of about 0.1 μm is formed on the n-type contact layer 4. On the crack prevention layer 5, while maintaining the substrate temperature at about 1150 ° C., an n-type second cladding layer 6 made of Si-doped Al _0.3 Ga _0.7 N having a thickness of about 1 μm and a thickness of about 50 nm were formed. The n-type first cladding layer 7 made of Si-doped GaN is formed.

Next, with the substrate temperature kept at about 880 ° C., five undoped G layers were formed on the n-type first cladding layer 7.
The MQW light emitting layer 8 is formed by alternately stacking an aN barrier layer and four undoped Ga _0.85 In _0.15 N well layers.
To form. Then, with the substrate temperature kept at about 1150 ° C., the p-type first cladding layer 9 made of Mg-doped GaN having a thickness of about 40 nm is formed on the MQW light emitting layer 8.
Mg-doped AlGaN having a film thickness of about 0.45 μm
(Al composition: 0.08) p-type second cladding layer 1
A cap layer 11 made of p-type GaN having a thickness of 0 and about 50 nm is sequentially formed.

Then, in a predetermined region on the cap layer 11,
As shown in FIG. 3, a striped Ni mask layer 18 having a width of about 2 μm is formed. Then, using the Ni mask layer 18 as a mask, the cap layer 11 and the p-type second clad layer 10 are converted to the p-type first clad by using, for example, CF ₄ as an etching gas by using RIE (reactive ion etching) method or the like. Etch until layer 9 is exposed. As a result, as shown in FIG.
A current passage portion (ridge portion) 12 including a p-type second clad layer 10 and a cap layer 11 having a width of 10 is formed. Then, the Ni mask layer 18 is removed.

Next, a Si nitride layer (not shown) such as Si ₃ N ₄ is formed so as to cover the entire surface by using, for example, ECR plasma CVD method, followed by photolithography technology and BHF (buffered fluorine). By patterning using wet etching using acid), a mask layer 13 as shown in FIG. 4 is formed. The mask layer 13 is formed on the upper surface of the current passage portion 12 (cap layer 11) and a partial region on the upper surface of the p-type first cladding layer 9. The mask layer 13 on the upper surface of the p-type first cladding layer 9 has a thickness of approximately 10 μm centered on the current passage portion 12.
It is formed to have an opening having a width of m. The upper surface of the p-type first cladding layer 9 is exposed in the openings between the mask layers 13.

Next, as shown in FIG. 5, using the mask layer 13 as a mask, a reduced pressure MOV is applied at a pressure of about 1 × 10 ⁴ Pa.
A current blocking layer 14 having a thickness of about 3 μm is selectively grown on the exposed upper surface of the first p-type cladding layer 9 by the PE method so as to cover the side portions of the current passage portion 12. In this case, for example, while holding the substrate temperature at about 880 ° C., the flow rate of NH _3, is about three times the flow rate of NH ₃ used in the MOVPE method under atmospheric pressure. Under these conditions,
When the current blocking layer 14 is grown, on the upper surface of the p-type first cladding layer 9 exposed in the openings between the mask layers 13,
Further, the current block layer 14 is formed on a partial region on the upper surface of the mask layer 13 so as to cover the side portions of the current passage portion 12. After that, the current passage portion 12 (cap layer 11)
The upper mask layer 13 is removed.

Then, as shown in FIG. 6, about 1 × 10 ⁴
A Mg-doped Ga having a film thickness of about 3 μm to about 5 μm is formed on the current passage portion 12 (cap layer 11) and the current block layer 14 using a reduced pressure MOVPE method at a pressure of Pa.
A p-type contact layer 15 made of N is formed. In this case, the Mg-doped GaN is grown on the current passage portion 12 (cap layer 11) and the current block layer 14 under the condition that the Mg-doped GaN is selectively grown. As a result, the p-type contact layer 15 having a width of about 8 μm is formed around the current passage portion 12. MOV
As a source gas for forming each of the layers 2 to 11, 14 and 15 made of a nitride-based semiconductor on the sapphire substrate 1 by using the PE method, for example, trimethylaluminum (TMAl), trimethylgallium (TMGa), trimethyl are used. Indium (TMIn), NH ₃ , SiH ₄ and cyclopentadienyl magnesium (CP ₂ Mg) are used.

Next, a metal mask and EB (Elec
For example, a width of about 70 μm and a width of about 3 μm to about 5 μm are formed in a predetermined area on the wafer by using the tron beam evaporation method.
Forming a striped Ni mask (not shown) having a film thickness of. After that, using the RIE method or the like, the mask layer 13, the p-type first cladding layer 9, and the Ni mask are used as an etching gas with CF ₄ as an etching gas.
MQW light emitting layer 8, n-type first cladding layer 7, n-type second cladding layer 6, crack prevention layer 5 and n-type contact layer 4
By removing a part of the area, a mesa portion having a width of about 70 μm is formed as shown in FIG.
Then, the Ni mask is removed using hydrochloric acid or the like.

Finally, as shown in FIG. 1, the p-side electrode 16 made of Au / Pd is formed on the p-type contact layer 15. Further, on the surface of the n-type contact layer 4 exposed by etching, the n-side electrode 17 made of Au / Ti is formed.
To form. Then, the wafer formed as described above is cleaved to form a resonator structure having a resonator length of about 300 μm in the extending direction of the stripe shape. In this way, the nitride-based semiconductor laser device according to the first embodiment is manufactured.

In the method for manufacturing the nitride-based semiconductor laser device of the first embodiment, as described above, the current blocking layer 14 is formed by selective growth using the mask layer 13 as a mask, whereby the vicinity of the current passage portion 12 is formed. The current blocking layer 14 can be formed only in the above. Thereby, strain applied to the current block layer 14 due to a difference in lattice constant between the current block layer 14 and the n-type contact layer 4 made of n-type GaN having a large thickness (about 4 μm) is relaxed. You can

(Second Embodiment) FIG. 8 is a sectional view showing a nitride-based semiconductor laser device according to the first embodiment of the present invention. The structure of the nitride-based semiconductor laser device according to the second embodiment of the present invention will be described with reference to FIG. The nitride-based semiconductor laser device according to the second embodiment is a real refractive index type laser device. In addition, in the above-described first embodiment, an example in which the mask layer is used to selectively grow the current block layer only in the vicinity of the current passage portion is shown. In the second embodiment, the step portion is used to form the current block layer. An example is shown in which a current block layer having a thickness smaller than the thickness of the current block layer in the vicinity of the current passage portion is formed in a region other than the vicinity of the current passage portion by selective growth. The details will be described below.

That is, as the structure of the nitride-based semiconductor laser device according to the second embodiment, sapphire (000
1) A buffer layer 22 made of AlGaN having a thickness of about 15 nm and an undoped GaN layer 23 having a thickness of about 0.5 μm are formed on a plane substrate 21 (hereinafter referred to as “sapphire substrate 21”). ing. An n-type contact layer 24 made of n-type GaN having a mesa-shaped portion with a width of about 10 μm and a film thickness of about 4 μm is formed on the undoped GaN layer 23. The sapphire substrate 21 is an example of the “substrate” in the present invention,
The n-type contact layer 24 is an example of the “nitride-based semiconductor layer” in the present invention.

On the mesa portion of the n-type contact layer 24, n-type Ga _0.95 In _0.05 having a film thickness of about 0.1 μm is formed.
The crack prevention layer 25 made of N, the Si-doped Al _0.1 Ga _0.9 N having a thickness of about 1 μm, the second cladding layer 26 made of Si, and the Si-doped GaN having a thickness of about 50 nm.
N-type first cladding layer 27 and GaInN
MQW light emitting layer 28 composed of multiple quantum wells (MQW)
Are formed to have a width of about 10 μm. The MQW light emitting layer 28 includes five undoped GaN barrier layers having a thickness of about 4 nm and 4 having a thickness of about 4 nm.
It has a structure in which two undoped Ga _0.85 In _0.15 N well layers are alternately laminated. The MQW light emitting layer 28 is an example of the “light emitting layer” in the present invention.

A p-type first clad layer 29 made of Mg-doped GaN having a width of about 2 μm and a film thickness of about 40 nm is formed almost at the center of the upper surface of the MQW light emitting layer 28. In addition, a width of about 2 μm and a width of about 0.45 μm are provided so as to contact almost the entire upper surface of the p-type first cladding layer 29.
Mg-doped AlGaN (Al composition:
0.08) p-type second cladding layer 30 and
P-type GaN having a width of about 2 μm and a film thickness of about 50 nm
A cap layer 31 made of is formed. These p
The width W1 (in the second embodiment, in the second embodiment, the first type clad layer 29, the p-type second clad layer 30, and the cap layer 31).
A current passage portion 32 having a thickness of about 2 μm is formed.

Further, M located on both sides of the current passage portion 32
The exposed portion (terrace) 28a on the upper surface of the QW light emitting layer 28 is
Each has a width of about 4 μm. Also, the terrace 28a
A stepped portion 100 having a height of about 3 μm is formed on the outer side of the. That is, the step portion 100 is formed at a position separated from the current passage portion 32 by the width of the terrace 28a (about 4 μm). As described above, the stepped portion 100 has the current passage portion 32.
It is preferable to form the current passage portion 32 at a position separated by 1 to 3 times the width (about 2 μm) of the current passage section 32 (2 times (about 4 μm) in this embodiment). The p-type first cladding layer 2
9 and the p-type second cladding layer 30 are examples of the “cladding layer” in the present invention.

Further, a part of the side portion of the current passage portion 32 and M
A current block layer 33 made of undoped Al _0.3 Ga _0.7 N is formed so as to cover the upper surface of the QW light emitting layer 28 and the step portion 100. In this case, the MQW light emitting layer 28
The current blocking layer 33 formed on the upper surface of the current blocking layer 33 has a thickness of about 3 μm on the terrace 28a near the current passage portion 32, and in the step portion 100, the current blocking layer 33 near the current passage portion 32. The film thickness is smaller than that of In this case, the step portion 10 including the current passage portion 32
The distance W2 between 0s (about 10 μm) is formed to be 3 times or more and 7 times or less (five times in this embodiment) the width W1 (about 2 μm) of the current passage portion 32.

Then, about 1 μm is formed so as to cover a part of the upper surface of the current block layer 33 near the current passage portion 32 and the current passage portion 32 (cap layer 31) exposed on the current block layer 33. And a p-type contact layer 34 made of Mg-doped GaN having a film thickness of 3 is formed. Each of the layers 22 to 31, 33, and 34 has a wurtzite structure and is formed by growing in the [0001] direction of the nitride-based semiconductor. Further, as a source gas for forming each of the layers 22 to 31, 33 and 34 made of a nitride semiconductor on the sapphire substrate 21 by using the MOVPE method, for example, trimethylaluminum (TMAl), trimethylgallium (TMGa) is used. , Trimethylindium (TMIn), NH ₃ , SiH _4, and cyclopentadienyl magnesium (CP ₂ Mg) are used.

Au / Pd is formed on the p-type contact layer 34.
Is formed on the p-side electrode 35. An n-side electrode 36 made of Au / Ti is formed on the exposed surface of the n-type contact layer 24.

In the second embodiment, as described above, the current blocking layer 33 is provided in the vicinity of the current passage portion 32 by about 3 μm.
Of the current blocking layer 3 in the step portion 100 which is a region other than the vicinity of the current passage portion 32.
3 is thinly formed, the current blocking layer 33 is formed.
And the strain applied to the current block layer 33 due to the difference in lattice constant between the n-type contact layer 24 made of n-type GaN and formed on the sapphire substrate 21 with a large thickness (about 4 μm). It becomes easy to concentrate on a region (stepped portion 100) having a small thickness. As a result, lattice defects and cracks are likely to occur in regions where the thickness of the current block layer 33 is small except for the vicinity of the current passage portion 32.
It is possible to suppress the occurrence of cracks and lattice defects in the current blocking layer 33 near the current passage portion 32. As a result, the thickness of the current blocking layer 33 in the vicinity of the current passage portion 32 can be increased, so that the lateral optical confinement can be stabilized.

9 to 14 are sectional views for explaining the method for manufacturing the nitride-based semiconductor laser device according to the second embodiment of the present invention. With reference to FIGS. 8 to 14,
The method for manufacturing the nitride-based semiconductor laser device according to the second embodiment will be described.

First, under the same growth conditions as those of the first embodiment shown in FIG. 2, as shown in FIG.
About 15 sapphire substrate 21 is formed by using the OVPE method.
buffer layer 2 made of AlGaN having a thickness of nm
2, undoped GaN layer 2 having a thickness of about 0.5 μm
3, n-type contact layer 24 made of Si-doped GaN having a thickness of about 4 μm, n having a thickness of about 0.1 μm
Crack prevention layer 25 made of Ga _0.95 In _0.05 N, an n-type second cladding layer 26 made of Si-doped Al _0.1 Ga _0.9 N having a thickness of about 1 μm, and n made of Si-doped GaN having a thickness of about 50 nm. Mold first clad layer 2
Form 7.

Next, five undoped GaN barrier layers and four undoped Ga layers are formed on the n-type first cladding layer 27.
_The MQW light emitting layer 28 is formed by alternately stacking _0.85 In _0.15 N well layers. Then, Mg-doped Ga having a film thickness of about 40 nm is formed on the MQW light emitting layer 28.
The p-type first clad layer 29 made of N, Mg-doped AlGaN having a thickness of about 0.45 μm (Al composition: 0.0
8) p-type second cladding layer 30 and about 50 nm
A cap layer 31 made of p-type GaN having a film thickness of 3 is formed.

Then, in a predetermined region on the cap layer 31,
As shown in FIG. 10, a striped Ni mask layer (not shown) having a width of about 10 μm is formed. Then, using the Ni mask layer as a mask, the cap layer 31, the p-type second clad layer 30, the p-type first clad layer 29, the MQW light emitting layer 28, and the like, using CF ₄ as an etching gas, using RIE or the like. n-type first cladding layer 2
7. Partial regions of the n-type second cladding layer 26, the crack prevention layer 25 and the n-type contact layer 24 are removed by etching. Thereby, the step portion 100 is formed. Then, the Ni mask layer is removed.

Then, a striped Ni mask layer (not shown) having a width of about 2 μm is formed on the cap layer 31.
To form. Then, using the Ni mask layer as a mask, the cap layer 31 and the p-type second cladding layer 3 are formed by using, for example, CF ₄ as an etching gas by using the RIE method or the like.
0 and p-type first clad layer 29, MQW light emitting layer 28
After etching to expose the Ni mask layer, the Ni mask layer is removed. As a result, as shown in FIG. 11, about 2 μm
A current passage portion (ridge portion) 32 including a p-type first clad layer 29, a p-type second clad layer 30, and a cap layer 31 having a width of 4 is formed. In this case, the current passage portion 32
The MQW light emitting layer 28 on both sides of the
A terrace 28a having a width of m is formed. After that, the current passage portion 3 is formed by using, for example, the ECR plasma CVD method.
A mask layer 37 made of Si nitride such as Si ₃ N ₄ having a width of about 2 μm and a film thickness of about 0.5 μm is formed only on the upper surface of 2 (cap layer 31).

Next, as shown in FIG.
With a pressure of about 1 × 10 ⁴ Pa and a reduced pressure MOVPE
Method, the current block layer 33 is selectively grown. Thereby, a partial region of the side of the current passage portion 32, the upper surface of the MQW light emitting layer 28, the MQW light emitting layer 28, the n-type first cladding layer 27, the n-type second cladding layer 26, and the crack prevention layer 25. And the side surface of the n-type contact layer 24 (the step portion 10
0) and the upper surface of the n-type contact layer 24 so as to cover the current blocking layer 33 made of undoped AlGaN.
Is formed. By performing the selective growth using the step portion 100, the current blocking layer 33 formed in the vicinity of the current passage portion 32 on the MQW light emitting layer 28 has a thickness of about 3 mm.
The step portion 100 is formed with a large film thickness of μm.
The current blocking layer 33 formed in the above is formed with a smaller film thickness than the current blocking layer 33 in the vicinity of the current passage portion 32. After that, the mask layer 37 on the current passage portion 32 (cap layer 31) is removed.

Then, as shown in FIG. 13, about 1 × 10
Using a reduced pressure MOVPE method at a pressure of ⁴ Pa, a part of the current block layer 33 near the current path part 32 and the current path part 32 (cap layer 31) exposed on the current block layer 33 are removed. Mg with a film thickness of about 1 μm to cover
A p-type contact layer 34 made of doped GaN is formed.

Next, a striped Ni mask layer (not shown) having a width of about 70 μm and a film thickness of about 3 μm to about 5 μm is formed in a predetermined region on the wafer by using a metal mask and an EB vapor deposition method. To form. And this N
By using the i mask layer as a mask, a partial region of the current blocking layer 33 and the n-type contact layer 24 is removed by using RIE or the like, for example, CF ₄ as an etching gas, and as shown in FIG. A part of the upper surface of the mold contact layer 24 is exposed. Then, the Ni mask is removed using hydrochloric acid or the like.

Finally, as shown in FIG. 8, a p-side electrode 35 made of Au / Pd is formed on the p-type contact layer 34. Further, on the surface of the n-type contact layer 24 exposed by etching, the n-side electrode 3 made of Au / Ti is formed.
6 is formed. Then, the wafer formed as described above is cleaved to form a resonator structure having a resonator length of about 300 μm in the extending direction of the stripe shape. In this way, the nitride-based semiconductor laser device of the second embodiment is manufactured.

In the method for manufacturing the nitride-based semiconductor laser device of the second embodiment, the crystallinity of the current block layer 33 is formed by forming the current block layer 33 by selective growth using the step portion 100 as described above. Can be improved. In addition, the current blocking layer 3 is formed by using the step portion 100.
By selectively growing 3, the region of the current blocking layer 33 having a small thickness can be easily formed in the step portion 100 located in a region other than the vicinity of the current passage portion 32. As a result, the strain applied to the current block layer 33 due to the difference in lattice constant between the current block layer 33 and the n-type contact layer 24 made of n-type GaN having a large thickness (about 4 μm) causes It becomes easy to concentrate on the region where the thickness of the layer 33 is small. As a result, it is possible to suppress the occurrence of cracks and lattice defects in the current blocking layer 33 near the current passage portion 32.

(Third Embodiment) FIG. 15 shows a third embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a nitride-based semiconductor laser device according to an embodiment. The structure of the nitride-based semiconductor laser device according to the third embodiment of the present invention will be described with reference to FIG. In this third embodiment, a real index guided type self-aligned nitride semiconductor laser device will be described.

The structure of the nitride-based semiconductor laser device according to the third embodiment is an n-type Si (111) plane substrate 41.
Approximately 15n on (hereinafter referred to as "n-type Si substrate 41")
Buffer layer 4 made of n-type AlGaN having a thickness of m
2, n-type G made of n-type GaN having a thickness of about 4 μm
aN layer 43, n-type Ga _0.95 having a thickness of about 0.1 μm
A crack prevention layer 44 made of In _0.05 N, an n-type second clad layer 45 made of n-type AlGaN having a thickness of about 1 μm, and an n-type first clad layer made of n-type GaN having a thickness of about 50 nm. 46 is formed.

On the n-type first cladding layer 46, G
An MQW light emitting layer 47 formed of a multiple quantum well (MQW) of aInN is formed. The MQW light emitting layer 47 includes five undoped GaN barrier layers having a thickness of about 4 nm and four undoped Ga _0.85 having a thickness of about 4 nm.
It has a structure in which In _0.15 N well layers are alternately laminated.
The n-type Si substrate 41 is an example of the “substrate” in the present invention, and the n-type GaN layer 43 is an example of the “nitride-based semiconductor layer” in the present invention. The MQW light emitting layer 47 is an example of the “light emitting layer” in the present invention.

On the MQW light emitting layer 47, a p-type first cladding layer 48 made of Mg-doped GaN having a film thickness of about 40 nm is formed. In a partial region on the upper surface of the p-type first cladding layer 48, S having an opening with a width of about 8 μm is formed.
A mask layer 49 made of Si nitride such as i ₃ N ₄ is formed. Further, on the upper surface of the p-type first cladding layer 48 exposed in the openings between the mask layers 49, there is an opening and the undoped AlGa having a film thickness of about 3 μm.
A current blocking layer 50 made of N (Al composition: 0.2) is formed with a width W2 (about 8 μm). On the p-type first clad layer 48 in the opening of the current blocking layer 50, Mg-doped AlGaN (A having a thickness of about 0.45 μm) is formed.
A p-type second cladding layer 52 having an l composition of 0.08) is formed. The p-type second cladding layer 52 has an inverted mesa shape (inverted trapezoidal shape), and the surface of the p-type second cladding layer 52 on the p-type first cladding layer 48 side is about 2 μm.
It is formed to have a width W1 of m. The side surface of the p-type second cladding layer 52 is formed so as to contact the inner side surface of the opening of the current blocking layer 50. In addition,
The p-type first cladding layer 48 is an example of the “first cladding layer” in the present invention, and the p-type second cladding layer 52 is an example of the “second cladding layer” in the present invention.

On the upper surface of the current block layer 50,
A mask layer 51 made of Si nitride such as Si ₃ N ₄ is formed. A p-type contact layer 53 made of Mg-doped GaN having a film thickness of about 3 μm to about 5 μm is formed on the p-type second cladding layer 52 and the mask layer 51. Due to the p-type second cladding layer 52 and the p-type contact layer 53, the width W1 (in the third embodiment, about 2
μm) is formed. The width of the opening between the mask layers 49 (the total width of the current passage portion and the current block layer 50) W2 (about 8 μm) is equal to the width W1 of the current passage portion (the lower surface of the p-type second cladding layer 52) (about 2μ
m) to 3 times or more and 7 times or less (4 times in this embodiment)
Is set to. This is for the following reason.

That is, when the total width W2 of the current passage portion and the current block layer 50 is smaller than three times the width W1 of the current passage portion, the formation range of the current block layer 50 becomes too small, so that Directional light confinement becomes insufficient. Further, when the total width W2 of the current passage portion and the current block layer 50 is larger than 7 times the width W1 of the current passage portion, the strain applied to the current block layer 50 increases, so that the current block layer 50 is increased in strain. Many lattice defects occur and cracks occur. For this reason, it is preferable to set the total width W2 of the current passage portion and the current block layer 50 within a range of 3 times or more and 7 times or less of the width W1 of the current passage portion. In addition, each of the layers 42 to 48, 50, 52 and 53 has a wurtzite structure and is composed of a nitride-based semiconductor [000
1] direction.

Au / Pd is formed on the p-type contact layer 53.
Is formed on the p-side electrode 54. An n-side electrode 55 made of Au / Ti is formed on the back surface of the conductive n-type Si substrate 41.

In the third embodiment, as described above, the current block layer 50 is formed within the range of the width W2 (about 8 μm) of the opening between the mask layers 49, so that the current block layer 50 is formed in the current path. It can be formed only near the portion. As a result, compared with the case where the current blocking layer 50 is formed in the vicinity of the current passage portion and on the entire surface other than the vicinity,
The width of the current blocking layer 50 becomes smaller. As a result, the current block layer 50 is added to the current block layer 50 due to the difference in lattice constant between the current block layer 50 and the n-type GaN layer 43 made of n-type GaN formed with a large thickness (about 4 μm) on the Si substrate 41. Since the strain can be relaxed, the generation of cracks or lattice defects in the current blocking layer 50 can be suppressed. As a result, the thickness of the current blocking layer 50 can be increased, and the lateral optical confinement can be stabilized.

16 to 19 are sectional views for illustrating the method for manufacturing the nitride-based semiconductor laser device according to the third embodiment of the present invention. A method of manufacturing the nitride-based semiconductor laser device according to the third embodiment will be described below with reference to FIGS.

First, as shown in FIG. 16, M under atmospheric pressure
Using the OVPE method, while maintaining the substrate temperature at about 1150 ° C., the buffer layer 42 made of n-type AlGaN having a thickness of about 15 nm and the Si having a thickness of about 4 μm are formed on the n-type Si substrate 41. N-type G made of doped GaN
The aN layer 43 is formed. Next, with the substrate temperature kept at about 880 ° C., about 0.1 μm was formed on the n-type GaN layer 43.
A crack prevention layer 44 made of n-type Ga _0.95 In _0.05 N having a film thickness of is formed. On the crack prevention layer 44, while maintaining the substrate temperature at about 1150 ° C., about 1 μm
m-thickness n-type second cladding layer 45 made of Si-doped Al _0.15 Ga _0.85 N and Si having a thickness of about 50 nm
An n-type first cladding layer 46 made of doped GaN is formed.

Next, with the substrate temperature kept at about 880 ° C., five undoped GaN barrier layers and four undoped Ga _0.85 In _0.15 N were formed on the n-type first cladding layer 46.
The MQW light emitting layer 47 is formed by alternately stacking well layers. Then, with the substrate temperature kept at about 1150 ° C., the p-type first cladding layer 48 made of Mg-doped GaN having a film thickness of about 40 nm is formed on the MQW light emitting layer 47.

Thereafter, as shown in FIG. 17, a stripe-shaped mask layer 49 made of Si nitride such as Si ₃ N ₄ having an opening with a width of about 8 μm is formed on the upper surface of the p-type first cladding layer 48. To form. Then, using the mask layer 49 as a mask, a reduced pressure MOVPE is performed at a pressure of about 1 × 10 ⁴ Pa.
On the upper surface of the p-type first cladding layer 48 exposed in the opening between the mask layers 49 by using the
By selectively growing (Al composition: 0.2), the current blocking layer 50 made of undoped AlGaN (Al composition: 0.2) having a film thickness of about 3 μm is formed.
In this case, for example, in a state where the substrate temperature was increased to about 100 ° C., the flow rate of NH _3, is about three times the flow rate of NH ₃ used in the MOVPE method under atmospheric pressure. When the current blocking layer 50 is grown under such conditions, the mask layer 49
Undoped AlGaN selectively grows upward from the upper surface of the p-type first cladding layer 48 exposed in the opening between the undoped AlGa and the mask layer 49.
N is not grown. As a result, the mask layer 4 is formed on the upper surface of the p-type first cladding layer 48 exposed between the mask layers 49.
The current blocking layer 50 is formed within the width W2 (see FIG. 15) of about 8 μm of the opening between the holes 9.

Next, as shown in FIG. 18, a mask layer 51 made of SiN is formed on the upper surface of the current block layer 50 except for the portion which becomes the current passage portion. And
Using the mask layer 51 as a mask, using the RIE method or the like,
For example, using CF ₄ as an etching gas, the current blocking layer 50 is etched until the upper surface of the p-type first cladding layer 48 is exposed by a width of about 2 μm. As a result, an opening serving as a current passage portion is formed in the current block layer 50.

Next, as shown in FIG. 19, the p-type first cladding layer 48 exposed in the opening of the current blocking layer 50.
On the upper surface of the depressurized MOVP with a pressure of about 1 × 10 ⁴ Pa.
Using the E method, Mg-doped AlGaN (Al composition: 0.
08) to grow the p-type second cladding layer 52.
Thereby, the p-type second having a width (bottom width) of about 2 μm is formed.
The clad layer 52 is formed in a self-aligned manner. Then, on the upper surface of the p-type second cladding layer 52 and the mask layer 5
A p-type contact layer 53 made of Mg-doped GaN and having a film thickness of about 3 μm to about 5 μm is formed on the substrate 1.

The layers 42 to 48 made of a nitride semiconductor are formed on the n-type Si substrate 41 by the MOVPE method.
As a source gas for forming 50, 52 and 53, for example, trimethylaluminum (TMAl), trimethylgallium (TMGa), trimethylindium (TMIn), NH ₃ , SiH ₄ and cyclopentadienyl magnesium (CP ₂ Mg) are used. And so on.

Finally, as shown in FIG. 15, the p-side electrode 54 made of Au / Pd is formed on the p-type contact layer 53. Further, the n-side electrode 55 made of Au / Ti is formed on the back surface of the conductive n-type Si substrate 41. Then, the wafer formed as described above is cleaved to form a resonator structure having a resonator length of about 300 μm in the extending direction of the stripe shape. In this way, the self-aligned nitride semiconductor laser device according to the third embodiment is manufactured.

In the method for manufacturing the nitride-based semiconductor laser device of the third embodiment, as described above, the mask layer 49 is used to cover the region where the current passage portion is formed on the upper surface of the p-type first cladding layer 48. Current blocking layer 50 having an opening in the vicinity thereof
After the formation of the p-type second p-type clad layer 48 in the opening of the current blocking layer 50, the p-type second clad layer constituting the current passage part is formed.
By forming the cladding layer 52 and the p-type contact layer 53, it is possible to easily form a self-aligned nitride-based semiconductor laser device in which the current block layer 50 is formed only near the current passage portion. As a result, the width of the current block layer 50 becomes smaller than that in the case where the current block layer 50 is formed in the vicinity of the current passage portion and on the entire surface other than the vicinity. Therefore, the current blocking layer 50
And the strain applied to the current blocking layer 50 due to the difference in lattice constant between the n-type GaN layer 43 made of n-type GaN and having a large thickness (about 4 μm) can be relaxed. It is possible to suppress the occurrence of cracks and lattice defects in 50.

Further, in the third embodiment, as described above,
By forming the current blocking layer 50 by selective growth using the mask layer 49 as a mask, the crystallinity of the current blocking layer 50 can be improved in the self-aligned nitride-based semiconductor laser device.

(Fourth Embodiment) FIG. 20 shows a fourth embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a nitride-based semiconductor laser device according to an embodiment. The structure of the nitride-based semiconductor laser device according to the fourth embodiment of the present invention will be described with reference to FIG. In the fourth embodiment, an n-type GaN substrate is used in a self-aligned nitride semiconductor laser device. Further, in the fourth embodiment, a complex index guided type nitride semiconductor laser device will be described. Less than,
The details will be described.

Nitride-based semiconductor laser according to the fourth embodiment
The structure of the device is as follows: n-type GaN (0001) plane substrate 6
1 (hereinafter referred to as “n-type GaN substrate 61”),
N-type Ga having a film thickness of 0.1 μm_0.95In_0.05From N
Crack prevention layer 62, Si having a film thickness of about 1 μm
Doped Al_0.3Ga_0.7N-type second cladding layer 6 made of N
3, made of Si-doped GaN having a thickness of about 50 nm
N-type first clad layer 64 and GaInN multiplex
An MQW light emitting layer 65 composed of a quantum well (MQW) is formed.
Has been. The MQW light emitting layer 65 has a thickness of about 4 nm.
5 undoped GaN barrier layers with a thickness of about 4 nm
4 undoped Ga having only_0.85In _0.15N well layer
It has a structure in which and are alternately stacked. Note that n-type GaN
The substrate 61 is an example of the “GaN substrate” in the present invention, and M
The QW light emitting layer 65 is an example of the “light emitting layer” in the present invention.

On the MQW light emitting layer 65, a p-type first cladding layer 66 made of Mg-doped GaN having a film thickness of about 40 nm is formed. In a partial region on the upper surface of the p-type first cladding layer 66, S having an opening with a width of about 8 μm is formed.
A mask layer 67 made of Si nitride such as i ₃ N ₄ is formed. Further, on the upper surface of the p-type first cladding layer 66 exposed in the openings between the mask layers 67, there is an opening and an undoped Ga _0.85 film having a film thickness of about 3 μm.
The current blocking layer 68 made of In _0.15 N has a width W2 (about 8
μm). On the p-type first cladding layer 66 in the opening of the current blocking layer 68, Mg-doped AlGaN (Al composition: 0.0
The p-type second cladding layer 70 of 8) is formed. The p-type second cladding layer 70 has an inverted mesa shape (inverse trapezoidal shape), and the surface of the p-type second cladding layer 70 on the p-type first cladding layer 66 side has a width W1 of about 2 μm. Is formed in. The side surface of the p-type second cladding layer 70 is formed so as to contact the inner side surface of the opening of the current blocking layer 68. The p-type first cladding layer 66 is an example of the “first cladding layer” in the present invention, and the p-type second cladding layer 70 is an example of the “second cladding layer” in the present invention.

On the upper surface of the current block layer 68,
A mask layer 69 made of Si nitride such as Si ₃ N ₄ is formed. A p-type contact layer 71 made of Mg-doped GaN and having a film thickness of about 3 μm to about 5 μm is formed on the p-type second cladding layer 70 and the mask layer 69. Due to the p-type second clad layer 70 and the p-type contact layer 71, the width W1 (in the fourth embodiment, about 2
μm) is formed. The width of the opening between the mask layers 67 (total width of the current passage portion and the current block layer 68) W2 (about 8 μm) is equal to the width W1 (about the lower surface of the p-type second cladding layer 70) of the current passage portion. 2μ
It is set in the range of 3 times or more and 7 times or less of m). The reason for setting this range is the same as in the first embodiment. In addition, each of the layers 62 to 66, 68, 70 and 71 is
It has a wurtzite structure and a nitride-based semiconductor [0
It is formed by growing in the [001] direction.

Au / Pd is formed on the p-type contact layer 71.
The p-side electrode 72 is formed. On the back surface of the n-type GaN substrate 61 having conductivity, Au / Pt /
An n-side electrode 73 made of Ti / Al / Ti is formed so that Ti contacts the n-type GaN substrate 61 side.

In the fourth embodiment, as described above, the current blocking layer 68 is formed within the range of the width W2 (about 8 μm) of the opening between the mask layers 67, so that the current blocking layer 68 is formed. It can be formed only near the portion. As a result, compared with the case where the current blocking layer 68 is formed in the vicinity of the current passage portion and on the entire surface other than the vicinity,
The width of the current blocking layer 68 becomes smaller. As a result, the strain applied to the current blocking layer 68 due to the difference in the lattice constant between the current blocking layer 68 and the n-type GaN substrate 61 can be relaxed, so that cracks or lattice defects occur in the current blocking layer 68. Can be suppressed. As a result, the thickness of the current blocking layer 68 can be increased, and the optical confinement in the lateral direction can be stabilized.

21 to 24 are sectional views for illustrating the method for manufacturing the nitride-based semiconductor laser device according to the fourth embodiment of the present invention. 20 to 24, the method for manufacturing the nitride-based semiconductor laser device according to the fourth embodiment will be described below.

First, as shown in FIG. 21, M under atmospheric pressure
A crack prevention layer 62 made of n-type Ga _0.95 In _0.05 N having a film thickness of about 0.1 μm is formed on the n-type GaN substrate 61 by using the OVPE method while maintaining the substrate temperature at about 880 ° C. To do. An n-type second layer made of Si-doped Al _0.3 Ga _0.7 N having a film thickness of about 1 μm is formed on the crack prevention layer 62 while maintaining the substrate temperature at about 1150 ° C.
A clad layer 63 and an n-type first clad layer 64 made of Si-doped GaN having a film thickness of about 50 nm are formed.

Next, with the substrate temperature kept at about 880 ° C., five undoped GaN barrier layers and four undoped Ga _0.85 In _0.15 N were formed on the n-type first cladding layer 64.
The MQW light emitting layer 65 is formed by alternately stacking well layers. Then, with the substrate temperature kept at about 1150 ° C., the Mg-doped Ga is deposited on the MQW light emitting layer 65.
A p-type first cladding layer 66 made of N is formed.

After that, as shown in FIG. 22, a stripe-shaped mask layer 67 made of Si nitride such as Si ₃ N ₄ having an opening with a width of about 8 μm is formed on the upper surface of the p-type first cladding layer 66. To form. Then, using the mask layer 67 as a mask, a reduced pressure MOVPE is performed at a pressure of about 1 × 10 ⁴ Pa.
Of undoped GaInN on the upper surface of the p-type first cladding layer 66 exposed in the openings between the mask layers 67 by using the
Is selectively grown to form a current blocking layer 68 made of undoped GaInN having a film thickness of about 3 μm. In this case, for example, with the substrate temperature raised by about 100 ° C., the flow rate of NH ₃ is set to MOVP under atmospheric pressure.
The flow rate of NH ₃ used in the E method is about 3 times. When the current blocking layer 68 is grown under such conditions, the undoped GaInN is selectively grown upward from the upper surface of the p-type first cladding layer 66 exposed between the mask layers 67, and the mask layer is also formed. Undoped GaInN is not grown on 67. As a result, the current blocking layer 68 is formed on the upper surface of the p-type first cladding layer 66 exposed between the mask layers 67 within the range of the width W2 (see FIG. 20) of about 8 μm of the openings between the mask layers 67. It is formed.

Next, as shown in FIG. 23, a mask layer 69 made of SiN is formed on the upper surface of the current block layer 68 except for the portion which becomes the current passage portion. And
Using the mask layer 69 as a mask, using the RIE method or the like,
For example, using CF ₄ as an etching gas, the upper surface of the p-type first cladding layer 66 has a width W1 of about 2 μm (see FIG. 20).
The current blocking layer 68 is etched until it is exposed. As a result, an opening serving as a current passage portion is formed between the current block layer 68 and the mask layer 69.

Next, as shown in FIG. 24, the p-type first cladding layer 66 exposed in the opening of the current blocking layer 68.
On the upper surface of the depressurized MOVP with a pressure of about 1 × 10 ⁴ Pa.
Using the E method, Mg-doped AlGaN (Al composition: 0.
08) of the p-type second clad layer 70 is grown.
Thereby, the p-type second having a width (bottom width) of about 2 μm is formed.
The clad layer 70 is formed in a self-aligned manner. Then, on the upper surface of the p-type second cladding layer 70 and the mask layer 6
A p-type contact layer 71 made of Mg-doped GaN and having a film thickness of about 3 μm to about 5 μm is formed on the substrate 9.

Note that n-type GaN is formed by using the MOVPE method.
Layers 62 to 6 made of a nitride-based semiconductor on the substrate 61
As a raw material gas for forming 6, 68, 70 and 71, for example, trimethyl aluminum (TMAl),
Trimethyl gallium (TMGa), trimethyl indium (TMIn), NH ₃ , SiH ₄ and cyclopentadienyl magnesium (CP ₂ Mg) are used.

Finally, as shown in FIG. 20, a p-side electrode 72 made of Au / Pd is formed on the p-type contact layer 71. Further, an n-side electrode 73 made of Au / Pt / Ti / Al / Ti is formed on the back surface of the conductive n-type GaN substrate 61 so that Ti contacts the n-type GaN substrate 61 side. Then, the wafer formed as described above is cleaved to form a resonator structure having a resonator length of about 300 μm in the extending direction of the stripe shape. In this way, the self-aligned nitride semiconductor laser device according to the fourth embodiment is manufactured.

In the method for manufacturing the nitride-based semiconductor laser device of the fourth embodiment, as described above, the mask layer 67 is used to form the region where the current passage portion is formed on the upper surface of the p-type first cladding layer 66. After forming the current block layer 68 having an opening in the vicinity of, the p in the opening of the current block layer 68 is formed.
By forming the p-type second cladding layer 70 and the p-type contact layer 71 forming the current passage portion on the type first cladding layer 66, the current block layer 68 can be easily formed only in the vicinity of the current passage portion. It is possible to form a self-aligned nitride-based semiconductor laser device. As a result, the width of the current block layer 68 becomes smaller than that in the case where the current block layer 68 is formed in the vicinity of the current passage portion and on the entire surface other than the vicinity. Therefore, the current blocking layer 6
8 and the strain constant applied to the current blocking layer 68 due to the difference in lattice constant between the n-type GaN substrate 61 and the n-type GaN substrate 61.

Further, in the fourth embodiment, as described above,
By selectively growing the mask layer 67 as a mask to form the current block layer 68, the crystallinity of the current block layer 68 can be improved in the self-aligned nitride-based semiconductor laser device.

It should be understood that the embodiments disclosed this time are exemplifications in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and includes meaning equivalent to the scope of claims for patent and all modifications within the scope.

For example, Si ₃ N ₄ , SiO ₂ , Al ₂ O ₃ or Ti is further formed on the cavity facets of the nitride-based semiconductor laser devices formed in the first to fourth embodiments.
An end face high reflection film or an end face low reflection film such as a dielectric multilayer film in which O ₂ is laminated may be formed.

Further, in the above-mentioned first to fourth embodiments, the example in which the present invention is applied to the nitride-based semiconductor laser device has been shown, but the present invention is not limited to this, and may be applied to, for example, a surface-emitting type semiconductor laser device. The application of is also possible. In this case, assuming that the diameter of the light emitting region is B, for example, a mask layer having a substantially circular opening (preferably diameters 3B to 7B) is formed around the light emitting region, and the light emitting region in the opening of the mask layer is formed. The current blocking layer may be formed only around the area. Also,
After forming a stepped portion around a substantially circular terrace (flat portion) (preferably, diameter 3B to 7B) around the light emitting region,
If the current block layer is selectively grown using the step portion, a thin portion of the current block layer can be formed in the step portion so as to surround the light emitting layer. Further, application to a super luminescent light emitting diode element or the like is also possible.

Further, although the sapphire substrate, the n-type Si substrate and the n-type GaN substrate are used in the above-mentioned first to fourth embodiments, the present invention is not limited to this, and an insulating substrate such as spinel, GaAs, GaP. Alternatively, a 3-5 group semiconductor substrate such as InP or a SiC substrate may be used.

In the first to fourth embodiments, the MQ
Although GaInN is used as the material of the W light emitting layer, the present invention is not limited to this, and the light emitting layer is formed using a material having a band gap smaller than the band gaps of the n-type first cladding layer and the n-type second cladding layer. You may. In particular, Al
GaN, GaN or AlGaN / GaN / AlGaN
In a device having a light emitting layer having a bandgap larger than that of GaInN, such as a quantum well structure, AlBGaN is used.
Alternatively, since it is necessary to form a current block layer having a smaller lattice constant composed of AlGaN or the like having a large Al composition, the current block layer and the GaN layer or GaN
The difference in lattice constant from the substrate becomes large. Also in this case, the current blocking layer is formed only in the vicinity of the current passage portion, or the thickness of the current blocking layer is formed to be thin in the portion other than the vicinity of the current passage portion.
The same effect as that of the fourth embodiment can be obtained.

Although AlGaN is used as the material of the n-type first clad layer and the n-type second clad layer in the first to fourth embodiments, the present invention is not limited to this, and AlB may be used.
Any material such as GaN, AlBN or AlBGaInN having a lattice constant different from that of the underlying layer may be used.

In the first to fourth embodiments, the p-type layers are formed after the n-type layers are formed on the substrate. However, the present invention is not limited to this, and the p-type layers may be formed on the substrate. After forming the mold layers, the n-type layers may be formed.

Further, in the above-mentioned first to fourth embodiments,
The crystal structure of the nitride-based semiconductor may be a wurtzite type structure or a zinc blende type structure.

Further, in the above-mentioned first to fourth embodiments, the crystal growth of each of the nitride-based semiconductor layers is performed by using the MOVPE method or the like, but the present invention is not limited to this, and the HVPE method or TMAl, Crystal growth may be performed using a gas source MBE method using TMGa, TMIn, NH ₃ , SiH _4, Cp ₂ Mg, or the like as a source gas.

Further, in the second and third embodiments,
The Al composition of Al _x Ga _1-x N forming the current blocking layer was made larger than the Al composition of Al _z Ga _1-z N forming the n-type cladding layer formed on the substrate side with respect to the light emitting layer. As described above, generally, when the Al composition of the current block layer is large, cracks and lattice defects are likely to occur, but in the present invention, it is possible to suppress the occurrence of cracks and lattice defects in the current block layer. it can. As a result, n
Since the difference in the lattice constant between the mold cladding layer and the current blocking layer can be increased, the lateral optical confinement can be stabilized. Further, even when x ≦ z, the present invention can suppress the occurrence of cracks and lattice defects in the current blocking layer. As a result, the same effect can be obtained in that the current blocking layer having good crystallinity can be formed.

[0122]

As described above, according to the present invention, lateral light confinement can be stabilized in a nitride semiconductor light emitting device. In addition, it is possible to easily form a nitride-based semiconductor light emitting device capable of stabilizing light confinement in the lateral direction.

[Brief description of drawings]

FIG. 1 is a sectional view showing a nitride semiconductor laser device according to a first embodiment of the present invention.

FIG. 2 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the first embodiment of the present invention.

FIG. 3 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the first embodiment of the present invention.

FIG. 4 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the first embodiment of the present invention.

FIG. 5 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the first embodiment of the present invention.

FIG. 6 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the first embodiment of the present invention.

FIG. 7 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the first embodiment of the present invention.

FIG. 8 is a sectional view showing a nitride semiconductor laser device according to a second embodiment of the present invention.

FIG. 9 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the second embodiment of the present invention.

FIG. 10 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the second embodiment of the present invention.

FIG. 11 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the second embodiment of the present invention.

FIG. 12 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the second embodiment of the present invention.

FIG. 13 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the second embodiment of the present invention.

FIG. 14 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the second embodiment of the present invention.

FIG. 15 is a sectional view showing a nitride-based semiconductor laser device according to a third embodiment of the present invention.

FIG. 16 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the third embodiment of the present invention.

FIG. 17 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the third embodiment of the present invention.

FIG. 18 is a sectional view illustrating the method for fabricating the nitride-based semiconductor laser device according to the third embodiment of the present invention.

FIG. 19 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the third embodiment of the present invention.

FIG. 20 is a sectional view showing a nitride semiconductor laser device according to a fourth embodiment of the present invention.

FIG. 21 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the fourth embodiment of the present invention.

FIG. 22 is a cross-sectional view illustrating the method of manufacturing the nitride-based semiconductor laser device according to the fourth embodiment of the present invention.

FIG. 23 is a cross-sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the fourth embodiment of the present invention.

FIG. 24 is a sectional view illustrating the method for manufacturing the nitride-based semiconductor laser device according to the fourth embodiment of the present invention.

[Explanation of symbols]

1,21 Sapphire substrate (substrate) 4, 24 n-type contact layer (nitride-based semiconductor layer) 8, 28, 47, 65 MQW light emitting layer (light emitting layer) 9, 29 p-type first clad layer (clad layer) 10, 30 p-type second clad layer (clad layer) 12, 32 Current passage section 13, 49, 67 Mask layer 14, 33, 50, 68 Current blocking layer 41 n-type Si substrate (substrate) 43 n-type GaN layer (nitride-based semiconductor layer) 48, 66 p-type first clad layer (first clad layer) 52, 70 p-type second cladding layer (second cladding layer) 61 n-type GaN substrate 100 step

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Daijiro Inoue             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. F term (reference) 5F073 AA21 AA51 AA74 CA07 CB05                       CB22 DA05 DA25 EA15

Claims (26)

[Claims] 1. A light emitting layer, a clad layer formed on the light emitting layer and made of a first nitride-based semiconductor, the clad layer including a current passage portion, and a side surface of the current passage portion. A current blocking layer made of a nitride semiconductor, the current blocking layer is formed in the vicinity of the current passage portion, and the current blocking layer is formed in a region other than in the vicinity of the current passage portion. A nitride-based semiconductor light-emitting device including a non-doped region. 2. The nitride-based semiconductor light emitting device according to claim 1, wherein the current blocking layer is formed only near the current passage portion. 3. The nitride-based semiconductor light emitting device according to claim 1, wherein the total width of the current passage portion and the current block layer is 3 times or more and 7 times or less the width of the current passage portion. 4. The mask layer, which is formed on the cladding layer at a predetermined distance from the current passage portion, for selectively growing the current blocking layer.
4. The nitride-based semiconductor light emitting device according to any one of 3 to 3. 5. The mask layer is formed from the current passage portion,
The nitride-based semiconductor light-emitting device according to claim 4, wherein the nitride-based semiconductor light-emitting device is formed at intervals of 1 to 3 times the width of the current passage portion. 6. The mask layer is made of Si, Ti and Zr.
The nitride-based semiconductor light-emitting device according to claim 4, comprising an oxide film or a nitride film containing at least one element selected from the group consisting of: 7. The clad layer includes a convex portion that constitutes the current path portion and a flat portion, and the current block layer is formed on a side surface of the convex portion and on the flat portion. The nitride-based semiconductor light-emitting device according to claim 1. 8. The mask layer is formed on a flat portion of the cladding layer, and the current blocking layer is on a side surface of a convex portion of the cladding layer, on a flat portion of the cladding layer, and the mask layer. The nitride-based semiconductor light-emitting device according to claim 7, which is formed on and above. 9. The current blocking layer includes an opening, the cladding layer has a first cladding layer having a substantially flat upper surface, and the cladding layer is formed on the first cladding layer in the opening. A second cladding layer having a passage portion is included.
9. The nitride-based semiconductor light emitting device according to any one of 1. 10. A light emitting layer, a clad layer formed on the light emitting layer, comprising a first nitride-based semiconductor, including a current passage portion, and formed to cover a side surface of the current passage portion. 2. A current blocking layer made of a nitride-based semiconductor, wherein the current blocking layer includes a region in a region other than the vicinity of the current passage portion, the region having a smaller thickness than a thickness in the vicinity of the current passage portion. -Based semiconductor light emitting device. 11. A step portion formed in a region other than the vicinity of the current passage portion is further provided, and a region of the current block layer having a thickness smaller than a thickness in the vicinity of the current passage portion is formed in the step portion. The nitride-based semiconductor light emitting device according to claim 10, which is 12. The stepped portion extends from the current passage portion,
The nitride-based semiconductor light-emitting device according to claim 11, wherein the nitride-based semiconductor light-emitting device is formed at positions separated by 1 to 3 times the width of the current passage portion. 13. The current blocking layer comprises B, Ga, A
The nitride-based semiconductor light-emitting device according to claim 1, comprising N and at least one element selected from the group consisting of 1, In, and Tl. 14. The current blocking layer includes an AlGaN layer, and the current blocking layer is formed on either a GaN substrate or a GaN layer formed on the substrate. The nitride-based semiconductor light emitting device according to claim 1, further comprising: the second nitride-based semiconductor layer having a lattice constant smaller than that of GaN. 15. The current blocking layer includes the second nitride-based semiconductor layer having a refractive index smaller than that of the first nitride-based semiconductor layer forming the cladding layer.
The nitride-based semiconductor light-emitting device according to claim 1. 16. The current blocking layer includes the second nitride semiconductor layer having a lattice constant smaller than that of the first nitride semiconductor layer forming the cladding layer. 9. The nitride-based semiconductor light emitting device according to any one of 1. 17. The current blocking layer comprises Al _x Ga _1-x.
Includes N layers, the clad layer comprises Al _y Ga _1-y N layer, said current blocking layer and the cladding layer is formed so as to have a composition satisfying x> y, claim 1
17. The nitride-based semiconductor light emitting device according to any one of 16. 18. The current blocking layer is formed on either a GaN substrate or a GaN layer formed on the substrate, and the current blocking layer has a lattice constant larger than that of GaN. The nitride-based semiconductor light-emitting device according to claim 1, further comprising: the second nitride-based semiconductor layer having the same. 19. The nitride-based material according to claim 1, wherein the current blocking layer includes the second nitride-based semiconductor layer that absorbs light emitted from the light-emitting layer. Semiconductor light emitting device. 20. The current blocking layer comprises Ga _1-x In _x
14. An N layer, wherein the light emitting layer includes a Ga _1-y In _y N layer, and the current blocking layer and the light emitting layer are formed to have a composition satisfying x> y. , 18 and 1
9. The nitride-based semiconductor light emitting device according to any one of 9 above. 21. A step of forming, on the light emitting layer, a clad layer made of a first nitride semiconductor and including a current passage portion, and the vicinity of the current passage portion so as to cover a side surface of the current passage portion. And forming a current blocking layer made of a second nitride-based semiconductor on the region other than the vicinity of the current passage portion,
And a step of forming a region where the current blocking layer is not formed. 22. The method further comprising the step of forming a mask layer on the cladding layer at a predetermined distance from the current passage portion, wherein the step of forming the current blocking layer uses the mask layer to form the mask layer. 22. The nitride-based semiconductor according to claim 21, comprising the step of selectively growing the current blocking layer to form the current blocking layer only in the vicinity of the current passage portion so as to cover the side surface of the current passage portion. Method for manufacturing light emitting device. 23. A step of forming, on the light emitting layer, a clad layer made of a first nitride-based semiconductor and including a current passage portion; covering a side surface of the current passage portion; Forming a current blocking layer made of a second nitride-based semiconductor including a region having a smaller thickness than the region near the current passage portion in the region of 1. 24. The step of forming the current blocking layer includes the step of forming a step portion in a region other than the vicinity of the current passage portion, and the step of forming the step portion in the vicinity of the current passage portion. 24. The step of forming a region of the current block layer having a thickness smaller than a thickness of the current block layer in the vicinity of the current passage part in the step portion by selectively growing a layer. Of manufacturing a nitride-based semiconductor light-emitting device of. 25. A step of forming a first cladding layer made of a first nitride semiconductor on the light emitting layer, and a second nitride semiconductor having an opening in the vicinity of a region where the current passage portion is formed. And forming a second clad layer made of a third nitride-based semiconductor forming the current passage part on the first clad layer in the opening of the current block layer. A method for manufacturing a nitride-based semiconductor light emitting device, comprising: 26. The method further comprises the step of forming a mask layer on the first cladding layer at a predetermined distance from the region where the current passage portion is formed, and the step of forming the current block layer comprises: 26. The nitride according to claim 25, comprising the step of selectively growing the current blocking layer using the mask layer to form the current blocking layer only near a region where the current passage portion is formed. -Based semiconductor light emitting device manufacturing method.