JPH10242510A - Semiconductor light emitting element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the luminous efficiency and reliability of a semiconductor light emitting element, by correcting the lattice distortion of a Ga1-x Inx P(0<x<1) current diffusing layer by forming the current diffusing layer on a laminated semiconductor structure. SOLUTION: After an n-type GaAs buffer layer 2 is formed on an n-type GaAs substrate 1, a laminated semiconductor structure 12 composed of an n-type AlGaInP clad layer 3, an AlGaInP active layer 4, and a p-type AlGaInP clad layer 5 is formed on the buffer layer 2, and a p-type Ga1-x Inx P(0<x<1) current diffusing layer 6 is formed on the structure 12. A p-type electrode 11 is provided on the central part of the layer 6, and an n-type electrode 10 is provided on the whole lower surface of the substrate 1. Therefore, the luminous efficiency and reliability of a semiconductor light emitting element thus constituted can be improved, because the crystal defect in the current diffusing layer 6 can be reduced and, at the same time, the crystal defect resulting from the dislocation of the active layer 4, etc., constituting the light emitting section of the element can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting device such as a light emitting diode and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a semiconductor light emitting device using an AlGaInP-based semiconductor material has been used as a light emitting device for a visible region. The reason is that AlGaInP-based materials can be lattice-matched with a GaAs substrate.
This is because it has the feature that the band gap of the direct transition is the largest among II-V compound semiconductors.
In particular, for light emitting diodes, 550 nm to 690 nm
In this range, high emission efficiency can be obtained because direct transition light emission is performed.

However, the conventional surface-emitting type semiconductor light emitting device using an AlGaInP-based material has a problem in light extraction efficiency. This problem will be described with reference to a light emitting diode shown in FIG. This light emitting diode is formed on an n-type GaAs substrate 121 by n-type AlGaI.
A semiconductor multilayer structure 1212 including an nP first cladding layer 123, a GaInP active layer 124, and a p-type AlGaInP second cladding layer 125 is provided. A p-type electrode 1211 is provided on the center of the p-type cladding layer 125, and an n-type electrode 1210 is provided on the entire surface of the n-type substrate 121. Light generated in the GaInP active layer 124 which is a light emitting portion is transmitted to the p-type electrode 1211 on the p-type electrode 1211 side.
Is taken out from the part where it is not formed. In this light emitting diode, in order to increase the luminous efficiency, the current injected from the p-type electrode 1211 is applied to the GaInP active layer 1.
24. However, p-type AlGaI
Since the resistivity of the nP cladding layer 125 is large, the current spreads only a little in the p-type cladding layer 125, and GaInP
Light emission was obtained only in the portion of the active layer 124 immediately below the p-type electrode 1211. For this reason, in the conventional light emitting diode as shown in FIG. 12, the light extraction efficiency in the upper surface direction has become extremely small.

In order to solve this problem, a semiconductor light emitting device in which a GaP current diffusion layer is provided to spread the current to a wider portion is disclosed in, for example, Robert M. U by Fletcher et al.
nighted States Patent 5,000
8,718.

The proposed semiconductor light emitting device will be described below with reference to FIG. This semiconductor light emitting device is a light emitting diode, and n-type GaAs substrate 131 has n
-Type AlGaInP first cladding layer 133, GaInP active layer 134 and p-type AlGaInP second cladding layer 1
There is provided a semiconductor laminated structure 1312 consisting of 35, on which a p-type GaP current diffusion layer 136 is provided. p
The p-type electrode 13 is provided on the center of the GaP current diffusion layer 136.
11 are provided, and an n-type electrode 1310 is provided on the entire surface of the n-type substrate 131. In this semiconductor light emitting device,
The resistivity of the p-type GaP current diffusion layer 136C is p-type AlGa
Since the current is smaller than the resistivity of the InP cladding layer 135 and the current spreads in the p-type current diffusion layer 136, light emission can be obtained in a wide range in the GaInP active layer 124, and luminous efficiency is improved. Light generated in the active layer 134 is extracted from the p-type electrode 1311 side. However, the band gap of the p-type GaP current diffusion layer 136 is larger than the band gap of the p-type AlGaInP cladding layer 135, and the emitted light is p-type. Since the light is transmitted without being absorbed by the current diffusion layer 136, the luminous efficiency can be increased.

[0006]

However, FIG.
In the conventional semiconductor light emitting device shown in (1), since the GaP layer is used as the current diffusion layer, there are the following problems.

A first problem is that good crystallinity cannot be obtained with a GaP layer. In the GaP layer, Ga atoms and P atoms are strongly bonded to each other in the crystal, so that the Ga atoms are unlikely to diffuse (migrate) on the growth surface, resulting in island growth instead of good layer growth, and crystal defects occur. It is a probable cause. Due to these crystal defects, Ga
Since the crystallinity of the P layer is reduced and the resistivity is increased, this has been a factor of reducing the luminous efficiency and reliability of the semiconductor light emitting device.

[0008] The second problem is that the lattice constant of the GaP layer is
GaAs substrate and AlGaInP lattice-matched therewith
That is, the lattice constant of the system semiconductor layer is greatly different. G
The lattice constant of aAs is 5.65 angstroms, whereas the lattice constant of GaP is 5.45 angstroms, and a lattice mismatch of -3.54% occurs. The occurrence of the lattice mismatch also causes the first problem described above, and crystal defects occur in the GaP crystal to lower the crystallinity. This also reduced the luminous efficiency and reliability of the semiconductor light emitting device.

A third problem is that the lattice mismatch of GaP, which is the second problem, adversely affects the light emitting portion. Dislocations occur due to the -3.54% lattice mismatch, and crystal defects also occur in the active layer, the cladding layer, and the like, which are light emitting portions, and are factors that cause non-radiative recombination centers. For this reason, the luminous efficiency of the semiconductor light emitting element has been significantly reduced, and the reliability has also been significantly reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems of the prior art, and has as its object to provide a semiconductor light emitting device capable of greatly improving luminous efficiency and reliability and a method of manufacturing the same. Aim.

[0011]

According to the present invention, there is provided a semiconductor light emitting device having a semiconductor laminated structure including at least a first cladding layer of a first conductivity type, an active layer, and a second cladding layer of a second conductivity type on a substrate. Is provided, and a current diffusion layer made of Ga _1-x In _x P (0 <x <1) of the second conductivity type is provided on the semiconductor multilayer structure, thereby achieving the above object.

When the In composition ratio x of the current diffusion layer is 0 <x <
It is preferably 0.49.

When the In composition ratio x of the current diffusion layer is 0 <x <
It is preferably set to 0.27.

According to the semiconductor light emitting device of the present invention, a first conductive type first cladding layer, an active layer and a second conductive type second cladding layer are formed on a substrate.
A semiconductor multilayer structure including at least a cladding layer, and a second conductivity type Ga _1-x In _x P in which the In composition ratio x is changed in the layer thickness direction on the semiconductor multilayer structure.
A current diffusion layer composed of (0 <x <1) is provided;
Thereby, the above object is achieved.

The changed In composition ratio x of the current diffusion layer
Is preferably 0 <x <0.49.

The changed In composition ratio x of the current diffusion layer
Is preferably 0 <x <0.27.

The active layer is (Al _y Ga _{1 -y} ) _z In _{1 -z} P
(0 ≦ y ≦ 1, 0 ≦ z ≦ 1), Al _p Ga _1-p As (0 ≦
p ≦ 1) or In _q Ga _1-q As (0 ≦ q ≦ 1).

A pair of electrodes are provided with the substrate, the semiconductor laminated structure and the current diffusion layer interposed therebetween, and the current blocking layer is opposed to the electrode on the current diffusion layer side with the current diffusion layer interposed therebetween. May be provided.

An electrode on the side of the current diffusion layer may be provided on a central portion of the current diffusion layer, and light may be extracted from a portion where the electrode is not formed.

An electrode on the side of the current diffusion layer may be provided so as to surround a central portion of the current diffusion layer, and light may be extracted from a portion where the electrode is not formed.

When the current blocking layer is Ga _1-a In _a P (0 <a
<1) may be included.

The current blocking layer may be made of a compound semiconductor containing Al.

The current blocking layer is made of Al _b Ga _{1 -b} As (0 ≦
b ≦ 1) or (Al _c Ga _1-c ) _d In _1-d P (0 ≦ c ≦
1, 0 ≦ d ≦ 1).

According to the method of manufacturing a semiconductor light emitting device of the present invention, a semiconductor laminated structure including at least a first conductive type first clad layer, an active layer and a second conductive type second clad layer is provided on a substrate. A current blocking layer of the first conductivity type is provided on the semiconductor multilayer structure so as to partially overlap with the semiconductor stacked structure, and Ga _1-x In _{x of} the second conductivity type is formed over a portion where the current blocking layer is formed and a portion where the current blocking layer is not formed.
A current diffusion layer made of P (0 <x <1) is provided, one electrode is provided so as to interpose the current diffusion layer and face the current blocking layer, and the other electrode is provided on the substrate side. A method for manufacturing a semiconductor light emitting device provided with an electrode,
Forming the semiconductor laminated structure on the substrate and forming a current blocking layer forming layer made of an Al-containing compound semiconductor on the semiconductor laminated structure with a protective layer made of an Al-free material interposed therebetween; And selectively etching the layer for forming the current blocking layer and the protective layer to leave a current blocking layer so as to partially overlap the semiconductor multilayer structure, thereby achieving the above object. Is achieved.

In the etching, the etching may be performed so that the current blocking layer remains on the central portion of the semiconductor multilayer structure.

At the time of the etching, the etching may be performed so that the current blocking layer surrounds the central portion of the semiconductor multilayer structure and remains.

As the current blocking layer, Al _b Ga _{1 -b} As
(0 ≦ b ≦ 1) layer or (Al _c Ga _1-c ) _d In _1-d P
(0 ≦ c ≦ 1, 0 ≦ d ≦ 1) layers may be formed.

Hereinafter, the operation of the present invention will be described.

[0029] In the present invention, since the current is widened by semiconductor multilayer structure provided on _{Ga 1-x In x P (} 0 <x <1) current spreading layer, the light-emitting in a broad range of the active layer can get. Since the GaInP current diffusion layer contains In atoms having an atomic radius larger than that of P atoms, it is difficult for P atoms to move through the crystal during the crystal growth.
Crystal defects are less likely to occur. GaInP has a lattice mismatch with a GaAs substrate or a semiconductor layer formed thereon.
Since it is smaller than P, crystal defects hardly occur in the current diffusion layer itself, and crystal defects hardly occur in the active layer, the cladding layer, or the like, which is a light emitting portion.

When the In composition ratio x of the current diffusion layer is 0 <x <
Assuming 0.49, the GaInP active layer and the AlGaInP
Light emitted from the active layer can be transmitted without absorption, and crystal defects due to lattice mismatch with the GaAs substrate and the semiconductor layer formed thereon can be reduced.

The In composition ratio x of the current diffusion layer is set to 0 <x
If <0.27, the band gap is almost the same as that of GaP, so that the light generated in the active layer as the light emitting portion is not absorbed by the current diffusion layer, and the current diffusion layer does not deteriorate due to light absorption.

When the In composition ratio x of the current diffusion layer is gradually changed in the layer thickness direction, lattice distortion can be gradually relaxed and lattice distortion can be reduced.

The changed In composition ratio x of the current diffusion layer
Is 0 <x <0.49, the GaInP active layer and the Al
The light emitted from the GaInP active layer can be transmitted without absorption, and crystal defects due to lattice mismatch with the GaAs substrate and the semiconductor layer formed thereon can be reduced.

When the changed In composition ratio x of the current diffusion layer is 0 <x <0.27, the band gap is Ga
Since it is almost the same as P, light generated in the active layer, which is a light emitting portion, is not absorbed by the current diffusion layer, and deterioration of the current diffusion layer due to light absorption does not occur.

As the active layer, Al _y Ga _1-y ) _z In _1-z
P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1), Al _p Ga _1-p As (0
≦ p ≦ 1) or a compound semiconductor such as In _q Ga _1-q As (0 ≦ q ≦ 1), so that a light emitting portion with few crystal defects can be obtained.

When a current blocking layer is provided with the current diffusion layer interposed therebetween so as to face the electrode on the current diffusion layer side of the pair of electrodes provided with the substrate, the semiconductor laminated structure and the current diffusion layer interposed therebetween. In the current diffusion layer, a current is guided to a portion where the current blocking layer is not formed. Since the current is efficiently guided to a desired region of the active layer, the luminous efficiency in that portion is improved, and since no electrode is provided on the light emitting portion, the light extraction efficiency from the electrode non-formed portion is reduced. improves.

For example, if an electrode on the side of the current diffusion layer is provided on the center of the current diffusion layer, and a current blocking layer is provided so as to face the electrode, current is led to the peripheral portion of the active layer, and In this case, the light emission efficiency is improved, and the light extraction efficiency from the peripheral portion where the electrode is not formed is improved.

When an electrode on the side of the current diffusion layer is provided so as to surround the center of the current diffusion layer, and a current blocking layer is provided so as to face the electrode, current is led to the center of the active layer. Thus, the luminous efficiency at that portion is improved, and the light extraction efficiency from the central portion where the electrode is not formed is improved.

This current blocking layer is Ga _{1 -a} In _a P (0 <a
In the case of <1) layer, the lattice mismatch between the current blocking layer and the GaAs substrate or the semiconductor layer formed thereon is reduced, and the crystal defects are further reduced.

Further, Al _b Ga _{1 -b} As is used as a current blocking layer.
(0 ≦ b ≦ 1) or (Al _c Ga _1-c ) _d In _1-d P (0 ≦ c
When a compound semiconductor layer containing Al such as ≦ 1, 0 ≦ d ≦ 1) is used, a current blocking layer is formed on the semiconductor laminated structure via a protective layer made of a material containing no Al, thereby forming a protective layer. By selectively etching the current blocking layer, the current blocking layer can be disposed in a desired region.

[0041]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) In this embodiment 1, Ga
AlGa provided with _1-x In _x P (0 <x <1) current diffusion layer
An InP-based semiconductor light emitting device will be described.

FIG. 1 is a sectional view of the semiconductor light emitting device of the first embodiment.

This semiconductor light emitting device is a light emitting diode, and n-type GaAs (for example, Si
Buffer layer 2 (concentration: 5 × 10 ¹⁷ cm ⁻³ , thickness: 0.5 μm)
Is provided thereon, and n-type (Al _y Ga _1-y ) _z In _1-z P
(0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 0.5, z =
0.5, Si concentration 5 × 10 ¹⁷ cm ^-3 , thickness 1.0 μm)
Cladding layer _{3, (Al y Ga 1-} y) z In 1-z P (0 ≦ y ≦
1, 0 ≦ z ≦ 1, for example, y = 0, z = 0.5, thickness 0.
5 μm) Active layer 4 and p-type (Al _y Ga _1-y ) _z In _1-z
P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 0.5, z =
0.5, Zn concentration 5 × 10 ¹⁷ cm ^-3 , thickness 1.0 μm)
A semiconductor laminated structure 12 including the clad layer 5 is provided. On top of this, p-type Ga _1-x In _x P (0 <x <1, for example, x = 0.40, Zn concentration 5 × 10 ¹⁸ cm ⁻³ , thickness 5.
0 μm) The current spreading layer 6 is provided. A p-type electrode 11 is provided on the center of the p-type current diffusion layer 6, and an n-type electrode 10 is provided on the entire surface of the n-type substrate 1.

In the semiconductor light emitting device of this embodiment,
Since the Ga _1-x In _x P (x = 0.55) current diffusion layer 6 is used, lattice distortion can be improved. This will be described with reference to FIG.

FIG. 2 is a graph showing the relationship between the In composition x in Ga _1-x In _x P and the lattice mismatch ratio with GaAs. As can be seen from FIG. 2, when In composition x = 0.49 in Ga _1-x In _x P, the lattice constant matches that of GaAs, and the lattice mismatch rate becomes zero. In the present embodiment, Ga
The lattice mismatch ratio of the _1-x In _x P (x = 0.40) current diffusion layer 6 is -0.6%, and the lattice mismatch ratio of the GaP current diffusion layer in the conventional semiconductor light emitting device shown in FIG. -3.
The lattice distortion could be improved by 83% compared to 54%.

In the semiconductor light emitting device of this embodiment, (Al _y Ga _{1 -y} ) _z In _{1 -z} P (y = 0, z = 0.
5) Ga _1-x In _x P (x = 0.40) for the active layer 4
Since the current diffusion layer 6 is used, light generated in the active layer 4 is not absorbed by the current diffusion layer 6. This is illustrated in FIG.
This will be described with reference to FIG.

FIG. 3 is a graph showing the relationship between the In composition x in Ga _1-x In _x P and the band gap Eg. As can be seen from FIG. 3, when the In composition ratio x in Ga _1-x In _x P satisfies 0 <x ≦ 0.27, the transition is an X transition which is an indirect transition, so that the band gap Eg of GaP = 2. 27 eV
The band gap is almost the same as that of the GaP band gap. When 0.27 <x <1, the transition is a 遷移 transition which is a direct transition, and is therefore smaller than the band gap of GaP. In this embodiment, Ga _1-x
In _x P _(x = 0.40) is a band gap Eg = 2.0 eV of the current diffusion layer _{6, (Al y Ga 1-} y) z In 1-z
P (y = 0, z = 0.5) Band gap E of active layer 4
Since g is larger than 1.9 eV, light generated in the active layer 4 is extracted from the upper surface without being absorbed by the current diffusion layer 6.

As described above, in the semiconductor light emitting device of this embodiment, crystal defects in the current diffusion layer 6 can be reduced, and crystal defects due to dislocations in the active layer 4 or the like, which is a light emitting portion, can be greatly reduced. Efficiency and reliability could be greatly improved. Further, since the light generated in the active layer 4 is not absorbed by the current diffusion layer 6, the luminous efficiency does not decrease,
No deterioration of device characteristics due to light absorption occurred. Regarding the device characteristics, the luminous efficiency of the red light emitting diode with a wavelength of 650 nm is improved by 20% compared with the conventional device, and the reliability is increased by 1.5 times in the time required for the luminous intensity to be reduced to half under the condition of 60 ° C. when driven at 20 mA. did.

In this embodiment, the n-type clad layer, the active layer and the p-type clad layer are formed (Al _y G
a _1-y ) The composition ratios y and z of _z In _1-z P may be appropriately changed. This is the same in the following embodiments. Further, the structure of the semiconductor light emitting device is not limited to the light emitting diodes described in the present embodiment and the following embodiments.
Other structures can also be adopted as long as they are surface emitting semiconductor light emitting elements using a compound semiconductor material that lattice-matches with the As substrate.

(Embodiment 2) In this embodiment 2, Ga
A semiconductor light emitting device in which the In composition ratio x of the _1-x In _x P current diffusion layer is different from that of the first embodiment will be described.

FIG. 4 is a sectional view of the semiconductor light emitting device of the second embodiment.

This semiconductor light emitting device is a light emitting diode, and n type GaAs (for example, S
A buffer layer 22 having an i concentration of 5 × 10 ¹⁷ cm ⁻³ and a thickness of 0.5 μm is provided, and an n-type (Al _y Ga _1-y ) _z In
_1-z P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 1.0,
z = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.0 μ
m) cladding layer _{23, (Al y Ga 1-} y) z In 1-z P (0
≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 0.45, z = 0.
5, 0.5 μm thick active layer 24 and p-type (Al _y G
a _1-y ) _z In _1-z P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 1.0, z = 0.5, Zn concentration 5 × 10 ¹⁷ cm ⁻³ ,
A semiconductor multilayer structure 212 including a cladding layer 25 (thickness: 1.0 μm) is provided. On top of this, p-type Ga _1-x In _x
P (0 <x <1, for example, x = 0.2, Zn concentration 5 × 10
^A current diffusion layer 26 ( ¹⁸ cm ⁻³ , thickness 5.0 μm) is provided. On the central portion of the p-type current diffusion layer 26, the p-type electrode 2
The n-type electrode 2 is provided on the entire surface of the n-type substrate 21 side.
10 are provided.

In this embodiment, Ga _1-x In _x P
(X = 0.2) Since the current diffusion layer 26 is used, FIG.
As shown in FIG. 13, the lattice mismatch rate becomes -2.1%, and FIG.
The lattice distortion of the GaP current diffusion layer in the conventional semiconductor light emitting device shown in FIG.

Although the effect of reducing the lattice distortion is smaller than that of the first embodiment, the band gap of the current diffusion layer can be made larger in the second embodiment than in the first embodiment. In the semiconductor light emitting device of the present embodiment, as shown in FIG.
The band gap Eg of the _1-x In _x P (x = 0.2) current diffusion layer 26 is almost the same as the band gap of GaP 2.27.
a _{eV, (Al y Ga 1-} y) z In 1-z P (y = 0.4
5, z = 0.5) Band gap Eg of active layer 24 =
Since it is larger than 2.18 eV, green light generated in the active layer 24 is not absorbed by the current spreading layer 26 but is extracted from the upper surface.

As described above, in the semiconductor light emitting device of the present embodiment, since the crystal defects in the current diffusion layer 26 can be reduced, the luminous efficiency and the reliability can be greatly improved. The green light generated in the active layer 24 is
6, the luminous efficiency did not decrease, and the device characteristics did not deteriorate due to light absorption. Regarding the device characteristics, the luminous efficiency of the green light-emitting diode having a wavelength of 550 nm is improved by 30% compared with the conventional device, and the reliability is also improved by 20%.
The time required to reduce the luminous intensity by half under the condition of 60 ° C. at the time of driving with mA was increased by 2.0 times.

(Embodiment 3) In this embodiment 3, Ga
A semiconductor light emitting device in which the In composition ratio x of the _1-x In _x P current diffusion layer is different from that of the first and second embodiments will be described.

FIG. 5 is a sectional view of the semiconductor light emitting device of the third embodiment.

This semiconductor light emitting device is a light emitting diode, and n type GaAs (for example, S
A buffer layer 32 having an i concentration of 5 × 10 ¹⁷ cm ⁻³ and a thickness of 0.5 μm) is provided, and an n-type (Al _y Ga _1-y ) _z In
_1-z P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 1.0,
z = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.0 μ
m) cladding layer _{33, (Al y Ga 1-} y) z In 1-z P (0
≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 0.30, z = 0.
5, a 0.5 μm thick active layer 34 and a p-type (Al _y G
a _1-y ) _z In _1-z P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 1.0, z = 0.5, Zn concentration 5 × 10 ¹⁷ cm ⁻³ ,
A semiconductor laminated structure 312 composed of a cladding layer 35 (1.0 μm thick) is provided. On top of this, p-type Ga _1-x In _x
P (0 <x <1, for example, x = 0.01, Zn concentration 5 × 1
(0 ¹⁸ cm ⁻³ , thickness 5.0 μm) The current diffusion layer 36 is provided. A p-type electrode 311 is provided on the center of the p-type current diffusion layer 36, and an n-type electrode 310 is provided on the entire surface of the n-type substrate 31.

In this embodiment, Ga _1-x In _x P
(X = 0.1) Since the current diffusion layer 36 is used, FIG.
As shown in FIG. 13, the lattice mismatch rate of the GaP current diffusion layer in the conventional semiconductor light emitting device shown in FIG. However, in the present embodiment, the Ga _1-x In _x P (x = 0.1) current diffusion layer 36
By using, the crystallinity could be improved as compared with the GaP layer. This will be described below. G
In the aP layer, Ga atoms and P atoms are strongly bonded in the crystal, so that Ga atoms diffuse on the growth surface (migration).
However, the growth is not good and the growth becomes island-like, which causes crystal defects to occur easily. In contrast, In
In GaInP containing even a small amount of atoms, crystal defects are significantly reduced. The reason that the crystal defects are reduced as described above is that the In atom has a small bond energy with the P atom,
Atoms easily diffuse (migrate) on the growth surface,
It is considered that Ga atoms are also diffused along with this, good layer growth is obtained, crystal defects are reduced, and good crystallinity is obtained.

Further, in the semiconductor light emitting device of this embodiment, as shown in FIG. 3, Ga _{1 -x} In _x P (x = 0.0
1) the band gap Eg of the current diffusion layer 36 is substantially the same 2.27eV bandgap of GaP, (Al _y
Ga _1−y ) _z In _1−z P (y = 0.30, z = 0.5) Since the bandgap of the active layer 34 is larger than that of the active layer 34, the yellow light generated in the active layer 34 also has a current diffusion layer 36. And is taken out from the upper surface.

As described above, in the semiconductor light emitting device of the present embodiment, since the crystal defects in the current diffusion layer 36 can be reduced, the luminous efficiency and the reliability can be greatly improved. The green light generated in the active layer 34 is
6, the luminous efficiency did not decrease, and the device characteristics did not deteriorate due to light absorption. Regarding the device characteristics, the luminous efficiency of the yellow light emitting diode having a wavelength of 590 nm is improved by 20% compared with the conventional device, and the reliability is also improved by 20%.
The time required to reduce the luminous intensity by half under the condition of 60 ° C. at the time of driving with the mA was increased by 1.5 times.

(Embodiment 4) In this embodiment 4, Ga
The In composition ratio x of the _1-x In _x P current diffusion layer is gradually changed in the layer thickness direction, and In _q Ga _1-q As (0 ≦ q ≦
A semiconductor light emitting device using the method 1) will be described.

FIG. 6 is a sectional view of the semiconductor light emitting device of the fourth embodiment.

This semiconductor light emitting device is a light emitting diode, and n-type GaAs (for example, S
A buffer layer 62 having an i concentration of 5 × 10 ¹⁷ cm ⁻³ and a thickness of 0.5 μm is provided, and an n-type (Al _y Ga _1-y ) _z In
_1-z P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 0.5,
z = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.0 μ
m) cladding layer _{63, In q Ga 1-q} As (0 ≦ q ≦ 1,
For example q = 0.6, thickness 0.5 [mu] m) active layer 64 and p-type _{(Al y Ga 1-y)} z In 1-z P (0 ≦ y ≦ 1,0 ≦ z
≦ 1, for example, y = 0.5, z = 0.5, Zn concentration 5 × 1
(0 ¹⁷ cm ⁻³ , thickness 1.0 μm) A semiconductor multilayer structure 612 including the cladding layer 65 is provided. On top of that, p-type Ga _1-x In _x P (0 <x <1, for example, x = 0.4 → 0.
2, a Zn concentration of 5 × 10 ¹⁸ cm ⁻³ and a thickness of 5.0 μm). A p-type electrode 611 is provided on the center of the p-type current diffusion layer 66, and an n-type electrode 610 is provided on the entire surface of the n-type substrate 61.

In the present embodiment, the Ga _{1 -x} In _x P current diffusion layer 66 is grown by gradually changing the In composition ratio x from 0.4 to 0.2 in the thickness direction. As a result, the lattice distortion could be gradually reduced, and the occurrence of lattice distortion in the light emitting portion could be improved.

In the semiconductor light emitting device of the present embodiment, the band gap Eg of the Ga _{1 -x} In _x P (x = 0.4 → 0.2) current diffusion layer 66 is In _q Ga _{1 -q} As ( q =
0.6) Since the bandgap of the active layer 64 is larger than that of the active layer 64, the infrared light generated in the active layer 64 is not absorbed by the current diffusion layer 66 but is extracted from the upper surface.

As described above, in the semiconductor light emitting device of this embodiment, lattice distortion can be improved, and luminous efficiency and reliability can be greatly improved. Further, since the infrared light generated in the active layer 64 was not absorbed by the current diffusion layer 66, the luminous efficiency did not decrease, and the device characteristics did not deteriorate due to the light absorption. For the element characteristics, the wavelength 950
The luminous efficiency of the infrared light emitting diode of 30 nm is improved by 30% compared with the conventional one, and the reliability is 60% when driven at 20 mA.
The time required for the luminous intensity to be reduced to half under the condition of ° C. is 1.8.
Increased by a factor of two.

In the present embodiment, the composition ratio q of In _q Ga _{1 -q} As forming the active layer may be changed as appropriate. Further, an In _q Ga _1-q As (0 ≦ q ≦ 1) layer may be used as the n-type cladding layer and the p-type cladding layer.

(Embodiment 5) In this embodiment 5, Ga
An AlGaAs-based semiconductor light emitting device in which the In composition ratio x of the _1-x In _x P current diffusion layer is gradually changed in the thickness direction will be described.

FIG. 7 is a sectional view of the semiconductor light emitting device of the fifth embodiment.

This semiconductor light emitting device is a light emitting diode, and n type GaAs (for example, S
A buffer layer 72 having an i concentration of 5 × 10 ¹⁷ cm ⁻³ and a thickness of 0.5 μm) is provided, and an n-type Al _p Ga _{1 -p} As (0 ≦
p ≦ 1, for example, p = 0.7, Si concentration 5 × 10 ¹⁷ c
m ^-3 , thickness 1.0 μm) cladding layer 73, Al _p Ga _1-p
As (0 ≦ p ≦ 1, for example, p = 0, thickness 0.5 μm) active layer 74 and p-type Al _p Ga _1-p As (0 ≦ p ≦ 1, for example p = 0.7, Zn concentration 5 × 10) ¹⁷ cm ^-3 , thickness 1.
0 μm) Semiconductor laminated structure 712 including cladding layer 75
Is provided. A p-type Ga _1-x In _x P (0 <
x <1, for example, x = 0.2 → 0.01, Zn concentration 5 × 1
0 ¹⁸ cm ⁻³ , thickness 5.0 μm) current diffusion layer 76 is further provided thereon, and a p-type Ga _1-x In _x P (0 <x <1,
(For example, x = 0.01, Zn concentration 5 × 10 ¹⁸ cm ⁻³ , thickness 2 μm) The current diffusion layer 77 is provided. A p-type electrode 711 is provided on the center of the current diffusion layer 77, and an n-type electrode 710 is provided on the entire surface of the n-type substrate 71.

In the present embodiment, the Ga _{1 -x} In _x P current diffusion layer 76 is grown by gradually changing the In composition ratio x from 0.2 to 0.01 in the layer thickness direction. As a result, the lattice distortion could be gradually reduced, and the occurrence of lattice distortion in the light emitting portion could be improved.

In the semiconductor light emitting device of this embodiment, the band gap Eg of the Ga _{1 -x} In _x P (x = 0.2 → 0.01) current diffusion layer 76 is Al _p Ga _{1 -p} As ( p
= 0) Since it is larger than the band gap of the active layer 74, the infrared light generated in the active layer 74 is not absorbed by the current diffusion layer 76 but is extracted from the upper surface.

As described above, in the semiconductor light emitting device of this embodiment, lattice distortion can be improved, and luminous efficiency and reliability can be greatly improved. Further, since the infrared light generated in the active layer 74 was not absorbed by the current diffusion layer 76, the luminous efficiency did not decrease, and the device characteristics did not deteriorate due to the light absorption. Regarding element characteristics, wavelength 850
The luminous efficiency of the infrared light emitting diode of 10 nm is improved by 10% compared with the conventional one, and the reliability is 60% at 20 mA driving.
Under the condition of ° C., the time required for the luminous intensity to be reduced to half is 1.3.
Increased by a factor of two.

In this embodiment, Al _p Ga constituting the n-type cladding layer, the active layer and the p-type cladding layer is used.
The composition ratio p of _1-p As may be changed as appropriate.

(Embodiment 6) In this embodiment 6, a current blocking layer is provided on a central portion of a semiconductor multilayer structure, and a G layer is formed thereon.
AlG provided with a _1-x In _x P (0 <x <1) current diffusion layer
The aInP-based semiconductor light emitting device will be described.

FIG. 8 is a sectional view of a semiconductor light emitting device according to the sixth embodiment.

This semiconductor light emitting device is a light emitting diode, and n type GaAs (for example, S
A buffer layer 82 having an i concentration of 5 × 10 ¹⁷ cm ⁻³ and a thickness of 0.5 μm is provided, and an n-type (Al _y Ga _1-y ) _z In
_1-z P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 1.0,
z = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.0 μ
m) cladding layer _{83, (Al y Ga 1-} y) z In 1-z P (0
≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 0.15, z = 0.
5, 0.5 μm thick active layer 84 and p-type (Al _y G
a _1-y ) _z In _1-z P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 1.0, z = 0.5, Zn concentration 5 × 10 ¹⁷ cm ⁻³ ,
A semiconductor multilayer structure 812 including a cladding layer 85 (thickness: 1.0 μm) is provided. The semiconductor laminated structure 812
N-type Ga _1-a In _a P (0 <a <1, for example, a = 0.2, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 0.5 μm)
m) A current blocking layer 88 is provided, on which the current blocking layer 8 is formed.
8 over the formed portion and the non-formed portion of p-type Ga _1-x In _x
P (0 <x <1, for example, x = 0.2, Zn concentration 5 × 10
^A current spreading layer 86 is provided ( ¹⁸ cm ^-3 , thickness 5.0 μm). A p-type electrode 811 is provided on the center of the p-type current diffusion layer 86 so as to face the current blocking layer 88, and an n-type electrode 810 is provided on the entire surface of the n-type substrate 81.

In the semiconductor light emitting device of this embodiment,
Since the current blocking layer 88 is provided on the central portion of the semiconductor multilayer structure 812 and the current spreading layer 86 is provided thereon, the current injected from the p-type electrode 811 is further spread to the peripheral portion by the current spreading layer 86. In addition, the light extraction efficiency from the periphery where the p-type electrode 811 is not formed is further improved. Further, p-type Ga _1-a In _a P (0 <a
Since <1) was used, the lattice distortion was reduced and the luminous efficiency and the reliability were improved as in the case of the current diffusion layer 86. Regarding the device characteristics, the luminous efficiency of the light-emitting diode having a wavelength of 610 nm is improved by 30% compared with the conventional device, and the reliability is reduced by a factor of 2.5 when the luminous intensity is reduced to half at 60 ° C. at 20 mA. Increased.

In this embodiment, the current blocking layer is provided on the central portion of the semiconductor laminated structure in order to block the current injected into the central portion of the light emitting portion. However, the semiconductor laminated structure is provided on the central portion of the substrate. A current blocking layer may be provided so as to bury the surrounding area. The current blocking layer has the same conductivity type as the substrate, but may be an insulating material. These are the same in an embodiment 8 described later.

(Embodiment 7) In this embodiment 7, a current blocking layer is provided so as to surround the central portion of the semiconductor multilayer structure, and Ga _1-x In _x P (0 <x <1) current diffusion is provided thereon. An AlGaInP-based semiconductor light emitting device provided with a layer will be described.

FIG. 9 is a sectional view of a semiconductor light emitting device according to the seventh embodiment.

This semiconductor light emitting device is a light emitting diode, and n type GaAs (for example, S
A buffer layer 92 having an i concentration of 5 × 10 ¹⁷ cm ⁻³ and a thickness of 0.5 μm is provided, and an n-type (Al _y Ga _1-y ) _z In
_1-z P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 1.0,
z = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.0 μ
m) cladding layer _{93, (Al y Ga 1-} y) z In 1-z P (0
≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 0.4, z = 0.
5, 0.5 μm thick active layer 94 and p-type (Al _y G
a _1-y ) _z In _1-z P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 1.0, z = 0.5, Zn concentration 5 × 10 ¹⁷ cm ⁻³ ,
A semiconductor multilayer structure 912 including a 1.0 μm thick cladding layer 95 is provided. The semiconductor laminated structure 912
N-type Ga _1-a In _a P (0 <
a <1, for example, a = 0.2, Si concentration 5 × 10 ¹⁷ c
m ⁻³ , 0.5 μm in thickness. A current blocking layer 98 is provided, and p-type Ga _1-x In _x P (0 <x <1, for example, x) = 0.
2, Zn concentration 5 × 10 ¹⁸ cm ⁻³ , thickness 5.0 μm) A current diffusion layer 96 is provided. A p-type electrode 911 is provided thereon so as to surround the center of the p-type current diffusion layer 96 and face the current blocking layer 98, and the n-type substrate 91 has an n-type electrode 910 are provided.

In the semiconductor light emitting device of this embodiment,
Since the current blocking layer 98 is provided so as to surround the central portion of the semiconductor laminated structure 912 and the current diffusion layer 96 is provided thereon, the current injected from the p-type electrode 911 is applied to the central portion by the current diffusion layer 96. The light is efficiently concentrated from the central portion where the p-type electrode 911 is not formed. Further, as the current blocking layer 98, p-type Ga _1-a In _a P
Since (0 <a <1) was used, the lattice distortion was reduced and the luminous efficiency and the reliability were improved as in the case of the current diffusion layer 96. Regarding element characteristics, wavelength 550n
luminous efficiency of the green light emitting diode of m
5% improvement, and reliability is 60 ° C at 20 mA drive.
Under the conditions, the time required for the luminous intensity to decrease by half increased 2.7 times.

In this embodiment, the current blocking layer is provided so as to surround the central portion of the semiconductor laminated structure in order to block the current injected into the peripheral portion of the light emitting portion. A current blocking layer may be provided so as to surround the part and bury the part therein. The current blocking layer has the same conductivity type as the substrate, but may be an insulating material. The same applies to the ninth embodiment described later.

(Embodiment 8) In this embodiment 8, a compound semiconductor containing Al, for example, (Al _c Ga _{1 -c} ) _d In _{1 -d} P (0 ≦ c ≦ 1, 0 ≦ d ≦
1) A current blocking layer comprising 1) Ga _1-x In _x
An AlGaInP-based semiconductor light emitting device provided with a P (0 <x <1) current diffusion layer will be described.

FIG. 10C is a sectional view of a semiconductor light emitting device according to the eighth embodiment.

This semiconductor light emitting device is a light emitting diode. An n type GaAs (for example, Si concentration 5 × 10 ¹⁷ cm ⁻³ , 0.5 μm thick) buffer layer 102 is provided on an n type GaAs substrate 101, n-type (Al _y Ga _1-y ) _z
In _1-z P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 1.
0, z = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.
0 .mu.m) cladding layer _{103, (Al y Ga 1-} y) z In 1-z
P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 0.45, z
= 0.5, thickness 0.5 [mu] m) active layer 104 and the p-type _{(Al y Ga 1-y)} z In 1-z P (0 ≦ y ≦ 1,0 ≦ z ≦
1, for example, y = 1.0, z = 0.5, Zn concentration 5 × 10
^A semiconductor laminated structure 1012 including a ¹⁷ cm ⁻³ , 1.0 μm thick cladding layer 105 is provided. P _- type Ga _1-r In _r P (0 <r <
1, for example, r = 0.2, Zn concentration 5 × 10 ¹⁸ cm ⁻³ , thickness 0.5 μm). A protective layer 109 is provided, and an n-type (Al _c Ga _1-c ) _d In _{1- d} P (0 ≦ c ≦ 1, 0 ≦
d ≦ 1, for example, c = 0.2, d = 0.5, Si concentration 5 ×
(10 ¹⁷ cm ⁻³ , thickness 0.5 μm) A current blocking layer 108 is provided. Furthermore, the p-type Ga _1-x In _x P (0 <
x <1, for example, x = 0.2, Zn concentration 5 × 10 ¹⁸ c
m ⁻³ , thickness 5.0 μm). A p-type electrode 1011 is provided on a central portion of the p-type current diffusion layer 106 so as to face the current blocking layer 108,
An n-type electrode 1010 is provided on the entire surface of the n-type substrate 101.

This semiconductor light emitting device can be manufactured, for example, as follows.

First, as shown in FIG.
an n-type GaAs buffer layer 102 on an aAs substrate 101;
n-type _{(Al y Ga 1-y)} z In 1-z P cladding layer 103,
(Al _y Ga _{1 -y} ) _z In _{1 -z} P active layer 104, p-type (Al
_y Ga _1-y ) _z In _{1 -z} P cladding layer 105, p-type Ga _1-r
In _r P protective layer 109 and n-type (Al _c Ga _{1 -c} ) _d In
A layer 108a of _1- dP for forming a current blocking layer is sequentially grown.

Next, as shown in FIG. 10B, a current blocking layer 108 is formed by etching a layer for forming a current blocking layer while leaving only the central portion of the protective layer 109. At this time, by using an etchant having an etching rate dependent on Al, for example, a phosphoric acid (H ₃ PO ₄ ) -based etchant, the layer 108a for forming the current blocking layer made of a compound semiconductor containing Al and Al is included. Selective etching with the protective layer 109 made of a non-existing material becomes possible, and the etching can be stopped at the protective layer 109.

Thereafter, as shown in FIG. 10C, a p-type Ga _1-x In _x P current diffusion layer 106 is grown, and an n-type electrode 1010 and a p-type electrode 1011 are formed. Complete.

In the semiconductor light emitting device of this embodiment,
The current blocking layer 108 contains Al (Al _c Ga _{1 -c} ) _d In
_1-d P (c = 0.2, d = 0.5)
-Free Ga _{1 -r} In _r P (r = 0.2) protective layer 109
By performing the selective etching described above, the yield in the manufacturing process was significantly improved, and the cost was significantly reduced.

(Embodiment 9) In this embodiment 9, a current blocking made of a compound semiconductor containing Al, for example, Al _b Ga _{1 -b} As (0 ≦ b ≦ 1) surrounds the central portion of the semiconductor multilayer structure. Layer, and Ga _1-x In _x P (0 <
x <1) An AlGaInP-based semiconductor light emitting device provided with a current diffusion layer will be described.

FIG. 11C is a sectional view of the semiconductor light emitting device of the ninth embodiment.

This semiconductor light-emitting device is a light-emitting diode, and an n-type GaAs (for example, 5 × 10 ¹⁷ cm ⁻³ , 0.5 μm thick) buffer layer 112 is provided on an n-type GaAs substrate 111. n-type (Al _y Ga _1-y ) _z
In _1-z P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 1.
0, z = 0.5, Si concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.
0 μm) cladding layer 113, (Al _y Ga _1-y ) _z In _1-z
P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1, for example, y = 0.4, z =
0.5, thickness 0.5 μm) active layer 114 and p-type (A
_{l y Ga 1-y) z} In 1-z P (0 ≦ y ≦ 1,0 ≦ z ≦ 1, for example y = 1.0, z = 0.5, Zn concentration 5 × 10 ¹⁷ cm
^-3 , thickness 1.0 μm). A semiconductor laminated structure 1112 comprising a cladding layer 115 is provided. On the semiconductor laminated structure 1112, p-type Ga _1-r In _r P (0 <r <1, for example, r = 0.2, Zn concentration 5 × 10 ¹⁸ cm ⁻³ , thickness 0.
5 μm) protective layer 119 is provided, and n-type Al _b Ga _{1 -b} As (0 ≦ b ≦ 1, for example, b = 0.2, Si concentration 5 × 10 ¹⁷ cm ⁻³ , 0.5μ thickness
m) A current blocking layer 118 is provided. Further, a p-type Ga _1-x In _x P (0 <x <1, for example, x = 0.2,
A current diffusion layer 116 having a Zn concentration of 5 × 10 ¹⁸ cm ⁻³ and a thickness of 5.0 μm is provided. A p-type current spreading layer 1
16 so as to surround the central portion thereof and the current blocking layer 1
A p-type electrode 1111 is provided so as to face
An n-type electrode 1110 is provided on the entire surface of the mold substrate 111.

The semiconductor light emitting device can be manufactured, for example, as follows.

First, as shown in FIG.
an n-type GaAs buffer layer 112 on an aAs substrate 111,
n-type _{(Al y Ga 1-y)} z In 1-z P cladding layer 113,
(Al _y Ga _{1 -y} ) _z In _{1 -z} P active layer 114, p-type (Al
_y Ga _1-y ) _z In _{1 -z} P cladding layer 115, p-type Ga _1-r
A layer 118a for forming a current blocking layer made of an In _r P protective layer 119 and n-type Al _b Ga _{1 -b} As is sequentially grown.

Next, as shown in FIG. 11B, the current blocking layer 118 is etched by leaving a layer for forming a current blocking layer so as to surround the central portion of the protective layer 119.
To form At this time, by using an etchant having an Al dependency on the etching rate, for example, a phosphoric acid (H ₃ PO ₄ ) -based etchant, a current blocking layer formed of a compound semiconductor containing Al is formed in the same manner as in the eighth embodiment. Layer 118a and protective layer 11 made of a material not containing Al
9 can be selectively etched, and the etching can be stopped at the protective layer 119.

Thereafter, as shown in FIG. 11C, a p-type Ga _1-x In _x P current diffusion layer 116 is grown, and an n-type electrode 1110 and a p-type electrode 1111 are formed. Complete.

In the semiconductor light emitting device of this embodiment,
Current blocking layer 118 includes _{Al Al b Ga 1-b As} (b =
0.2), Ga _1-r In _r P not containing Al
(R = 0.2) By performing selective etching with the protective layer 119, the yield in the manufacturing process was significantly improved, and the cost was significantly reduced.

[0103]

As described in detail above, according to the present invention,
Since the lattice distortion of the current diffusion layer can be improved, the crystal defects of the current diffusion layer itself can be reduced, and the generation of crystal defects in the light emitting portion such as the active layer can be prevented. Can be improved.

When the In composition ratio x of the current diffusion layer is set to 0 <x <
0.49, the GaInP layer or the AlG
The light emitted from the aInP layer can be transmitted without being absorbed, and the crystal defects of the current diffusion layer can be reduced, so that the luminous efficiency and the reliability can be further improved.

The In composition ratio x of the current diffusion layer is set to 0 <x
By setting the value to <0.27, light absorption in the current spreading layer does not occur, and the crystallinity of the current spreading layer is improved.
Further, luminous efficiency and reliability can be improved.

By gradually changing the In composition ratio x of the current diffusion layer in the layer thickness direction, the lattice distortion is gradually relaxed. Therefore, the lattice distortion is further reduced to improve the luminous efficiency and the reliability. be able to.

The changed In composition ratio x of the current diffusion layer
Is set to 0 <x <0.49, light emitted from the GaInP layer or the AlGaInP layer can be transmitted without absorption, and crystal defects in the current diffusion layer can be reduced. Efficiency and reliability can be improved.

By setting the changed In composition ratio x of the current diffusion layer to 0 <x <0.27, light absorption in the current diffusion layer does not occur, and the crystallinity of the current diffusion layer is improved. Therefore, luminous efficiency and reliability can be further improved.

This current diffusion layer is made of (Al _y Ga _{1 -y} ) _z I
n _1-z P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1), Al _p Ga _1-p A
When used in a semiconductor light emitting device having a light emitting portion such as s (0 ≦ p ≦ 1) or In _q Ga _1-q As (0 ≦ q ≦ 1), a light emitting portion free of crystal defects can be obtained, and the luminous efficiency can be improved. Can be improved.

If a current blocking layer is provided with the current spreading layer interposed therebetween so as to face the electrode on the side of the current spreading layer, the current spreading layer efficiently conducts a current to a portion where the current blocking layer is not formed to emit light. The efficiency of light extraction from the non-electrode-formed portion can be increased, as well as the efficiency.

For example, if an electrode on the side of the current diffusion layer is provided on the center of the current diffusion layer and a current blocking layer is provided so as to face the electrode, light from the peripheral portion where no electrode is formed can be obtained. The extraction efficiency is improved.

Further, when the electrode on the side of the current diffusion layer is provided so as to surround the central portion of the current diffusion layer, and the current blocking layer is provided so as to face the electrode, the central portion where the electrode is not formed is provided. Light extraction efficiency is improved.

Ga _1-a In _a P (0 <a
<1) By using the layer, the lattice distortion of the current blocking layer is also improved, so that the luminous efficiency and the reliability can be improved.

The current blocking layer is made of Al _b Ga _{1 -b} As.
(0 ≦ b ≦ 1) or (Al _c Ga _1-c ) _d In _1-d P (0 ≦ c
By using a compound semiconductor containing Al such as ≦ 1, 0 ≦ d ≦ 1) or the like, a current blocking layer can be formed in a desired region by performing selective etching, so that the yield of the manufacturing process is greatly improved. In addition, the cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a semiconductor light emitting device according to a first embodiment.

FIG. 2 is a graph showing a relationship between an In composition x in Ga _1-x In _x P and a lattice mismatch ratio with respect to GaAs.

FIG. 3 is a graph showing a relationship between an In composition x in Ga _1-x In _x P and a band gap Eg.

FIG. 4 is a sectional view of a semiconductor light emitting device according to a second embodiment.

FIG. 5 is a sectional view of a semiconductor light emitting device according to a third embodiment.

FIG. 6 is a sectional view of a semiconductor light emitting device according to a fourth embodiment.

FIG. 7 is a sectional view of a semiconductor light emitting device according to a fifth embodiment.

FIG. 8 is a sectional view of a semiconductor light emitting device according to a sixth embodiment.

FIG. 9 is a sectional view of a semiconductor light emitting device according to a seventh embodiment.

FIG. 10 is a cross-sectional view showing a manufacturing step of the semiconductor light emitting device of the eighth embodiment.

FIG. 11 is a cross-sectional view showing a manufacturing step of the semiconductor light emitting device of the ninth embodiment.

FIG. 12 is a sectional view of a conventional semiconductor light emitting device.

FIG. 13 is a sectional view of a conventional semiconductor light emitting device.

[Description of Signs] 1, 21, 31, 61, 71, 81, 91, 101, 1
11 Substrate 2, 22, 32, 62, 72, 82, 92, 102, 1
12 buffer layer 3, 23, 33, 63, 73, 83, 93, 103, 1
13 n-type cladding layer 4, 24, 34, 64, 74, 84, 94, 104, 1
14 Active layer 5, 25, 35, 65, 75, 85, 95, 105, 1
15 p-type cladding layer 6, 26, 36, 66, 76, 86, 96, 106, 1
16 Current spreading layer 10, 210, 310, 610, 710, 810, 91
0, 1010, 1110 n-type electrode 11, 211, 311, 611, 711, 811, 91
1, 1011, 1111 p-type electrode 12, 212, 312, 612, 712, 812, 91
2, 1012, 1112 Semiconductor multilayer structure 77 Current diffusion layer 88, 98, 108, 118 Current blocking layer 109, 119 Protective layer

Claims (17)

[Claims] A semiconductor laminated structure including at least a first cladding layer of a first conductivity type, an active layer, and a second cladding layer of a second conductivity type is provided on a substrate, and a second clad layer is formed on the semiconductor laminated structure. A semiconductor light emitting device provided with a current diffusion layer made of conductive Ga _1-x In _x P (0 <x <1). 2. The current diffusion layer according to claim 1, wherein an In composition ratio x is 0 <x.
The semiconductor light emitting device according to claim 1, wherein <0.49 is satisfied. 3. The current diffusion layer according to claim 1, wherein an In composition ratio x is 0 <x.
The semiconductor light emitting device according to claim 1, wherein <0.27 is satisfied. 4. A semiconductor laminated structure including at least a first conductive type first clad layer, an active layer, and a second conductive type second clad layer is provided on a substrate, and the semiconductor laminated structure is provided on the semiconductor laminated structure. A semiconductor light emitting device provided with a current diffusion layer made of Ga _1-x In _x P (0 <x <1) of a second conductivity type in which an In composition ratio x is changed in a layer thickness direction. 5. The semiconductor light emitting device according to claim 4, wherein the changed In composition ratio x of the current diffusion layer is set to 0 <x <0.49. 6. The semiconductor light emitting device according to claim 4, wherein the changed In composition ratio x of the current diffusion layer is set to 0 <x <0.27. 7. The method according to claim 1, wherein the active layer is (Al _y Ga _{1 -y} ) _z In _{1 -z}
P (0 ≦ y ≦ 1, 0 ≦ z ≦ 1), Al _p Ga _1-p As (0
7. The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting device is made of ≦ p ≦ 1) or In _q Ga _1-q As (0 ≦ q ≦ 1). 8. A pair of electrodes are provided with the substrate, the semiconductor laminated structure, and the current diffusion layer interposed therebetween, and a current is supplied so as to face an electrode on the current diffusion layer side with the current diffusion layer interposed therebetween. The semiconductor light emitting device according to claim 1, further comprising a blocking layer. 9. The semiconductor light emitting device according to claim 8, wherein the electrode on the side of the current diffusion layer is provided on a central portion of the current diffusion layer, and light is extracted from a portion where the electrode is not formed. 10. The semiconductor according to claim 8, wherein an electrode on the side of the current diffusion layer is provided so as to surround a central portion of the current diffusion layer, and light is extracted from a portion where the electrode is not formed. Light emitting element. 11. The method according to claim 1, wherein the current blocking layer is Ga _1-a In _a P (0
The semiconductor light emitting device according to claim 9, wherein <a <1). 12. The semiconductor light emitting device according to claim 9, wherein said current blocking layer is made of a compound semiconductor containing Al. 13. The current blocking layer according to claim 1, wherein said current blocking layer is Al _b Ga _{1 -b} As.
(0 ≦ b ≦ 1) or (Al _c Ga _1-c ) _d In _1-d P (0
13. The semiconductor light emitting device according to claim 12, wherein ≤c≤1, 0≤d≤1). 14. A semiconductor laminated structure including at least a first conductive type first clad layer, an active layer, and a second conductive type second clad layer is provided on a substrate, and a semiconductor laminated structure is formed on the semiconductor laminated structure. A current blocking layer of the first conductivity type is provided so as to partially overlap;
A current diffusion layer made of Ga _1-x In _x P (0 <x <1) of the second conductivity type is provided over the portion where the current blocking layer is formed and the portion where the current blocking layer is not formed. A method for manufacturing a semiconductor light-emitting device in which one electrode is provided so as to face the current blocking layer and the other electrode is provided on the substrate side, wherein the semiconductor laminated structure is formed on the substrate. Forming a layer for forming a current blocking layer made of a compound semiconductor containing Al on the semiconductor laminated structure with a protective layer made of a material containing no Al interposed therebetween; and a layer for forming the current blocking layer. And selectively etching the protective layer to leave a current blocking layer so as to partially overlap the semiconductor laminated structure. 15. The method according to claim 14, wherein the etching is performed such that the current blocking layer remains on a central portion of the semiconductor multilayer structure during the etching. 16. The method for manufacturing a semiconductor light emitting device according to claim 14, wherein the etching is performed such that the current blocking layer surrounds a central portion of the semiconductor multilayer structure and remains. 17. The method according to claim 17, wherein the current blocking layer is formed of Al _b Ga _1-b A.
s (0 ≦ b ≦ 1) layer or (Al _c Ga _1-c ) _d In _1-d P
The method for manufacturing a semiconductor light emitting device according to claim 14, wherein (0 ≦ c ≦ 1, 0 ≦ d ≦ 1) layers are formed.