JPH10270752A - Semiconductor light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance light picking-up efficiency by efficiently passing current to a light-emitting portion, and by preventing light absorption, oxidation of current diffusion layers, and diffusion of p-type dopants. SOLUTION: An n-type clad layer 2, an active layer 3 and a p-type clad layer 4 are, respectively, provided one after another on an n-type GaAs substrate 1 with a current inhibition layer 6 arranged at the top center thereof. The layer 6 is provided thereon with a p-type current diffusion layer 7 made of a compound semiconductor which contains no Al or has an Al content of more than 0 and less than 0.3, and has a bandgap larger than the active layer 3. A p-type electrode 11 is further provided on the layer 7 in face-to-face relation with the current inhibition layer 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor light emitting device such as a light emitting diode.

[0002]

2. Description of the Related Art In recent years, a semiconductor light emitting device using an AlGaAs-based material or a GaInAs-based material among III-V compound semiconductor materials has attracted attention. The reason is,
This is because these semiconductor materials have a direct transition band gap, and light emission in a band of 0.7 μm to 1.2 μm can be obtained. Semiconductor light-emitting devices using these material systems are particularly applied to spatial communication and optical fiber communication as infrared communication devices, and improvement in optical output is required. For example, in the case of a pn junction type light emitting diode (LED) having a light emitting portion made of these materials on a GaAs substrate, in order to improve the light output, not only the light emission efficiency but also the light inside the device must be increased. It is important to realize effective light extraction to the outside of the element by reducing the absorption or adjusting the relative positional relationship between the light emitting unit and the electrode.

Conventionally, as one method of improving the light extraction efficiency to the outside of the device, a current diffusion layer is provided between the light emitting portion and the electrode on the light extraction side to diffuse the current uniformly throughout the light emitting portion. A method has been proposed (for example, see
-229665). This semiconductor light emitting device is a light emitting diode using an AlGaInP-based material for a light emitting portion,
Although a semiconductor light emitting device using an AlGaAs-based material and an AlGaInAs-based material has a different material system, the structure in which a current diffusion layer is provided between a semiconductor laminated structure and a light extraction side electrode is the same.

The proposed semiconductor light emitting device will be described below with reference to FIG.

In this semiconductor light emitting device, an n-type AlGaInP first cladding layer 15 is formed on an n-type GaAs substrate 151.
2. AlGaInP active layer 153 and p-type AlGaI
A semiconductor multilayer structure including an nP second cladding layer 154 is provided, and a p-type GaInP intermediate band gap layer 155 and an n-type AlGaInP current blocking layer 156 are provided thereon. The current blocking layer 156 is processed into, for example, a circular shape by selective etching with the intermediate band gap layer 155. A p-type AlGaAs current diffusion layer 157 is provided on the current blocking layer 156 and the intermediate band gap layer 155. A p-type electrode 15 is formed on the current diffusion layer 157 via a p-type GaAs contact layer 159.
11 are provided, and an n-type electrode 151 is provided on the n-type substrate 151 side.
0 is provided. The p-type electrode 1511 is formed so as to face the current blocking layer 156 by a lift-off method using a resist or the like or by etching.
The portion of the contact layer 159 where 11 is not provided is removed by selective etching.

According to this semiconductor light emitting device, the p-type electrode 1
The current injected from 511 into the current diffusion layer 157 spreads to the outside of the current blocking layer 156 in the current diffusion layer 157, and is then injected into the p-type second cladding layer 154. As described above, the light-emitting region can be expanded over a wide area other than immediately below the p-type electrode 1511, so that light extraction efficiency can be improved.

[0007]

However, FIG.
In the conventional semiconductor light emitting device shown in (1), since AlGaAs containing Al is used for the current diffusion layer 157, there are the following problems when using an AlGaAs-based material or a GaInAs-based material for the light emitting portion. .

The first problem is that device characteristics are deteriorated due to oxidation of Al contained in the current diffusion layer 157. Generally, in order to make the current diffusion layer 157 transparent with respect to light emission from the active layer 153 as a light emitting unit, the band gap of the current diffusion layer 157 needs to be larger than the band gap of the active layer 153. Al _f Ga _1-f
In the case of an infrared light emitting device (emission wavelength: 830 nm) in which the Al composition f of the As active layer 153 is 0.3, Al _g Ga _{1 -g} As
The Al composition g of the current diffusion layer 157 must be set to 0.4 or more. However, even if Al is contained in the compound, it has high reactivity and is easily bonded to oxygen or the like in the atmosphere. Therefore, when the Al composition in the current diffusion layer 157 becomes large,
The Al is oxidized by bonding with oxygen in the air, and the crystallinity of the current diffusion layer 157 is reduced. As a result, light absorption or the like due to formation of a deep level occurs, which adversely affects device characteristics. . In addition, semiconductor light-emitting elements are often used outdoors as display elements and the like, and are more easily oxidized under high-temperature and high-humidity conditions. The reliability was low.

The second problem is that the light absorption of the current diffusion layer 157 increases and the light extraction efficiency decreases.
For example, in the case of an infrared light emitting device (emission wavelength: 770 nm) in which the Al composition f of the Al _f Ga _{1 -f} As active layer 153 is 0.5, the Al composition _{g of} the Al _g Ga _{1 -g} As current diffusion layer 157 is You have to do more. However, in the region where the Al composition is 0.5 or more, AlGaAs makes an indirect transition, so that even if the Al composition is increased, the band gap does not increase so much, and the light absorption by the current diffusion layer 157 increases.

A third problem is that the p-type dopant contained in the current diffusion layer 157 has an adverse effect on the light emitting portion. For example, the Al _g Ga _{1 -g} As current diffusion layer 15
If the Al composition g of 7 is 0.7 or more, the ionization rate of a p-type dopant such as Zn or Mg becomes low, so that it is necessary to supply a large amount of the p-type dopant in order to set a desired carrier concentration. Yes, there are many p-type dopants other than lattice positions. However, these p-type dopants cause the cladding layer 15 to grow during crystal growth of the current diffusion layer 157 and the like.
2, 154 and the active layer 153, which adversely affect the device, resulting in deterioration of device characteristics.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems of the prior art. The present invention efficiently guides a current to a light emitting portion to increase luminous efficiency, and absorbs light by a current diffusion layer, oxidizes light, and reduces p. It is an object of the present invention to provide a high-luminance semiconductor light-emitting device in which diffusion of a type dopant and the like are prevented and light extraction efficiency is enhanced.

[0012]

According to the semiconductor light emitting device of the present invention, a current blocking layer is partially provided on a compound semiconductor laminated structure having a light emitting portion provided on a substrate. A compound containing no Al or having an Al composition of greater than 0 and less than or equal to 0.3 and having a band gap larger than that of the light-emitting portion over the semiconductor laminated structure where the current blocking layer is not formed. A current spreading layer made of a semiconductor is provided, and a light extraction side electrode is provided on the current spreading layer so as to face the current blocking layer, thereby achieving the above object.

[0013] The semiconductor light emitting device of the present invention comprises a compound semiconductor laminated structure having a light emitting portion provided on a substrate,
Contains no Al or has an Al composition greater than 0 and 0.3
A first current spreading layer made of a compound semiconductor having a band gap larger than that of the light emitting portion is provided; a current blocking layer is provided partially on the first current spreading layer; Above and over the first current spreading layer on which the current blocking layer is not formed, Al is not contained, or the Al composition is greater than 0 and 0.3 or less, and the band gap is larger than that of the light emitting portion. The second compound semiconductor
A second current spreading layer of a conductivity type is provided, and a light extraction side electrode is provided on the second current spreading layer so as to face the current blocking layer, thereby achieving the above object. You.

The compound semiconductor laminated structure includes at least a compound semiconductor layer of the first conductivity type and a compound semiconductor layer of the second conductivity type, and the semiconductor layer of the first conductivity type is more than the semiconductor layer of the second conductivity type. The current blocking layer provided on the substrate side may be made of a first conductivity type compound semiconductor or a high resistance material.

The compound semiconductor laminated structure includes at least a first conductivity type compound semiconductor layer and a second conductivity type compound semiconductor layer, and the first conductivity type semiconductor layer is more than the second conductivity type semiconductor layer. The current blocking layer is provided on the substrate side, the current blocking layer is made of a second conductivity type compound semiconductor, and since the current blocking layer is formed, a hetero barrier in a region where the current blocking layer is formed is not formed by the current blocking layer. It may be larger than the hetero barrier in the formation region.

The current diffusion layer is of the second conductivity type, and the material thereof is GaP, Zn _a Mg _{1 -a} S _{1 -b} Se _b (0 ≦ a ≦ 1, 0 ≦
_{b ≦ 1), Ga 1-} c In c N (0 ≦ c ≦ 1), (Al x G
a _1-x ) _1-y In _y P (0 <x ≦ 0.3, 0 ≦ y ≦ 1),
_{(Al s Ga 1-s)} 1-t In t N (0 <s ≦ 0.3,0 ≦ t
≦ 1) or (Al _p Ga _1-p ) _{1-q Inq} As (0 <p ≦
0.3, 0 ≦ q ≦ 1).

_Gn In _1-n P (0 ≦ n ≦ 1) and Al _m Ga _1- mA are provided between the current blocking layer and the semiconductor multilayer structure.
s (0 ≦ m ≦ 1) , (Zn d Mg 1-d) S 1-e Se e (0 ≦
d ≦ 1, 0 ≦ e ≦ 1), Ga _A In _1- AN (0 ≦ A ≦ 1)
Or _{(Al D Ga 1-D)} 1-E In E As (0 ≦ D ≦ 1,0 ≦
A protective layer comprising E ≦ 1) may be provided.

The light emitting portion is formed of Al _i Ga _{1 -i} As (0 ≦ i ≦
1) or (Al _j Ga _1-j ) _1-k In _k As (0 ≦ j ≦
1, 0 ≦ k ≦ 1).

The operation of the present invention will be described below.

In the semiconductor light emitting device of the present invention, since the current is spread by the current diffusion layer, the light emitting region can be expanded over a wide area other than immediately below the electrode, and the light extraction efficiency is improved. Since the band gap of the current spreading layer is larger than the band gap of the light emitting section, light from the light emitting section is not absorbed by the current spreading layer, and the light extraction efficiency is improved. Further, since the current diffusion layer does not contain Al or is made of a compound semiconductor having an Al composition of greater than 0 and less than or equal to 0.3, the current diffusion layer differs from the conventional semiconductor light emitting device using the AlGaAs current diffusion layer. Oxidation of the layer, light absorption by the current diffusion layer, p contained in the current diffusion layer
Diffusion of the type dopant does not occur, and the problems of deterioration of device characteristics and reliability can be improved.

When a current blocking layer is partially provided between the semiconductor laminated structure and the current diffusion layer, a current injected into the current diffusion layer is efficiently guided to a region where the current blocking layer is not formed. Since the current blocking layer faces the light extraction side electrode, luminous efficiency in a region other than immediately below the electrode is further improved.

When the current diffusion layer is divided into two layers and a current blocking layer is partially provided between the two layers and is opposed to the light extraction side electrode, the current blocking layer in the electrode side current diffusion layer is formed. Since the current can be spread in the current diffusion layer on the substrate side in addition to spreading the current in a region where no light is formed, light emission can be obtained in a wider region.

The current blocking layer may be made of a first conductivity type compound semiconductor or a high resistance material. In particular, when the current blocking layer is made of a high resistance material, there is no need to control the conductivity type of the current blocking layer or control the carrier concentration of the current blocking layer, so that the manufacturing process is simplified and In addition, adverse effects due to re-diffusion of impurities can be prevented.

The current blocking layer is formed such that the formation of the current blocking layer makes the heterobarrier in the formation region larger than that in the non-formation region.
It may be made of a conductive type compound semiconductor. In this case, since all the semiconductor layers on the light emitting portion can be of the same conductivity type, the manufacturing process can be simplified, and adverse effects due to re-diffusion of the opposite conductivity type impurity can be prevented. For example, the current blocking layer has a two-layer structure to increase the hetero barrier between them, the hetero barrier between the current blocking layer and the layer above it, or the hetero barrier between the current blocking layer and the layer below it. can do.

As the current diffusion layer, for example, GaP of the second conductivity type, Zn _a Mg _{1 -a} S _{1 -b} Se _b (0 ≦ a ≦ 1,
0 ≦ b ≦ 1), Ga 1-c In c N (0 ≦ c ≦ 1), (Al
_x Ga _1-x ) _1-y In _y P (0 <x ≦ 0.3, 0 ≦ y ≦
_{1), (Al s Ga 1} -s) 1-t In t N (0 <s ≦ 0.3,
0 ≦ t ≦ 1) or (Al _p Ga _1-p ) _{1-q Inq} As (0
<P ≦ 0.3, 0 ≦ q ≦ 1) and the like can be used.

The GaP layer does not contain Al, unlike the AlGaAs layer used in the conventional semiconductor light emitting device.
Since oxidation due to the bond between l and oxygen does not occur, there is no decrease in device characteristics such as deterioration in crystallinity or light absorption due to formation of deep levels, and a significant decrease in luminance under high temperature and high humidity conditions. Be improved. Further, since the GaP layer has a larger band gap than the AlGaAs layer used in the conventional semiconductor light emitting device, the absorption of light from the light emitting portion by the current diffusion layer can be reduced. The GaP layer has an Al composition g of 0.1.
Since the ionization rate of a p-type dopant such as Zn or Mg is higher than that of an Al _g Ga _1-g As layer having a thickness of 4 or more, the p-type dopant existing at a position other than the lattice position can be reduced.
It is possible to prevent the p-type dopant from diffusing into the cladding layer or the active layer during the crystal growth and adversely affecting device characteristics. Further, since the GaP layer can be provided with an electrode directly thereon, a contact layer as in a conventional semiconductor light emitting element is not required, and the number of manufacturing steps can be reduced to realize a significant cost reduction.

Zn _a Mg _1-a S _1-b Se _b (0 ≦ a ≦ 1,0
≦ b ≦ 1) The layer does not contain Al like the GaP layer,
Oxidation due to the bond between oxygen and oxygen does not occur, so there is no decrease in device characteristics such as reduction in crystallinity or light absorption due to formation of deep levels, and significant reduction in brightness under high temperature and high humidity conditions Is done. In addition, Zn _a Mg _1-a S _1-b Se _b (0 ≦ a ≦
The 1,0 ≦ b ≦ 1) layer can have a larger band gap than the GaP layer, so that the absorption of light from the light emitting portion by the current diffusion layer can be further reduced. further,
The Zn _a Mg _1-a S _1-b Se _b (0 ≦ a ≦ 1, 0 ≦ b ≦ 1) layer is capable of lattice matching with the GaAs substrate and the light emitting portion, and thus has a bad influence on the light emitting portion. Has no effect.

The Ga _1-c In _c N (0 ≦ c ≦ 1) layer is made of Ga
Like the P layer, it does not contain Al, and does not oxidize due to the bond between Al and oxygen. Therefore, it does not cause deterioration in device characteristics such as deterioration of crystallinity or light absorption due to formation of deep levels, and high temperature and high humidity. The reduction in brightness under conditions is also greatly improved. G
_{a 1-c In c N (} 0 ≦ c ≦ 1) layer, it is possible to increase further the bandgap than GaP layer, it is possible to further reduce the absorption of light from the light emitting portion due to current spreading layer. Further, since the GaInN layer can be provided with an electrode directly thereon, there is no need for a contact layer as in a conventional semiconductor light emitting device, and the number of manufacturing steps can be reduced to realize a significant cost reduction.

(Al _x Ga _{1 -x} ) _{1 -y} In _y P (0 <x ≦
In the 0.3, 0 ≦ y ≦ 1) layer, since the Al composition is 0.3 or less, the current diffusion layer is not easily oxidized, and the reliability does not decrease. Also, (Al _x Ga _{1 -x} ) _{1 -y} In _y P (0 <x ≦ 0.
3, 0 ≦ y ≦ 1) layer is made of AlGaAs used in a conventional semiconductor light emitting element even if the Al composition is 0.3 or less.
Since the band gap can be set larger than that of the layer, the absorption of light from the light emitting portion by the current diffusion layer can be reduced. Further, (Al _x Ga _{1 -x} ) _{1 -y} In _y P (0 <
The x ≦ 0.3, 0 ≦ y ≦ 1) layer can be lattice-matched with the GaAs substrate and the light emitting unit, and therefore does not adversely affect the light emitting unit.

[0030] _{(Al s Ga 1-s)} 1-t In t N (0 <s ≦
In the 0.3, 0 ≦ t ≦ 1) layer, since the Al composition is 0.3 or less, the current diffusion layer is not easily oxidized, and the reliability does not decrease. _{Further, (Al s Ga 1-s} ) 1-t In t N (0 <s ≦ 0.
3, 0 ≦ t ≦ 1) The layer can set the band gap larger than that of the GaP layer even when the Al composition is 0.3 or less, so that the current diffusion layer absorbs light from the light emitting portion. Can be reduced. _{Further, (Al s Ga 1-s} ) 1-t In t
Since an electrode can be directly provided on the N (0 <s ≦ 0.3, 0 ≦ t ≦ 1) layer, a contact layer as in a conventional semiconductor light emitting element is unnecessary, and the number of manufacturing steps is reduced. As a result, a significant cost reduction can be realized.

(Al _p Ga _1-p ) _1-q In _q As (0 <p ≦
In the 0.3, 0 ≦ q ≦ 1) layer, since the Al composition is 0.3 or less, the current diffusion layer is not easily oxidized, and the reliability does not decrease. Also, (Al _p Ga _1-p ) _{1-q Inq} As (0 <p ≦
The 0.3, 0 ≦ q ≦ 1) layer can have a band gap larger than that of the light-emitting portion made of GaInAs or the like even when the Al composition is 0.3 or less, so that light emission by the current diffusion layer is achieved. The absorption of light from the part can be reduced.

By providing a protective layer between the current blocking layer and the semiconductor laminated structure, it is possible to prevent the AlGaAs clad layer made of a material containing Al from being exposed and oxidized before regrowth. As this protective layer, for example, Ga
_n In _1-n P (0 ≦ n ≦ 1), Al _m Ga _1-m As (0 ≦ m
_{≦ 1), (Zn d Mg} 1-d) S 1-e Se e (0 ≦ d ≦ 1,0
≦ e ≦ 1), Ga _A In _1- AN (0 ≦ A ≦ 1) or (A
_{l D Ga 1-D) 1} -E In E As (0 ≦ D ≦ 1,0 ≦ E ≦ 1)
And the like can be used. In particular, if a material that can be selectively etched with the current blocking layer is used, the manufacturing process is greatly simplified.

As the light emitting portion, Al _i Ga _{1 -i} As (0 ≦
When the i <1) layer is used, a high-output semiconductor light-emitting device can be obtained in the infrared region in the 0.68 μm to 0.86 μm band. Further, (Al _j Ga _1-j ) _1-k In _k
When an As (0 ≦ j ≦ 1, 0 ≦ k ≦ 1) layer is used, 0.9
A high-output semiconductor light emitting device can be obtained in the infrared region of the band from 5 μm to 1.25 μm.

[0034]

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

(Embodiment 1) In this embodiment 1, Ga
An AlGaAs-based light emitting diode provided with a P current diffusion layer will be described.

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

This semiconductor light emitting device has an n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example, h
= 0.70, Si carrier concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.0 μm) Cladding layer 2, Al _i Ga _1-i As (0 ≦ i
≦ 1, for example, i = 0.30, thickness 0.5 μm) Active layer 3
And p-type Al _h Ga _1-h As (0 ≦ h ≦ 1, for example, h =
(0.70, Zn carrier concentration 5 × 10 ¹⁷ cm ⁻³ , thickness 1.0 μm) A semiconductor multilayer structure including a cladding layer 4 is provided, and p-type _Gn In _1-n P (0 ≦ n ≦ 1) is formed thereon. (For example, n = 0, thickness 0.1 μm). An n-type GaP (for example, Si carrier concentration of 2 × 10 ¹⁸ cm ⁻³ , thickness 0.3 μm) current blocking layer 6 is provided in a circular shape on the central portion of the protective layer 5. A p-type GaP (for example, a Zn carrier concentration of 5 × 10 ¹⁸ c) is formed over the protective layer 5 where the layer 6 is not formed.
m ⁻³ , thickness 5.0 μm). A p-type electrode 11 made of Au-Zn or the like is provided in a circular shape on the center of the current diffusion layer 7 so as to face the current blocking layer 6, and an n-type electrode made of Au-Ge or the like is provided on the n-type substrate 1 side. The mold electrode 10 is provided on the entire surface.

This semiconductor light emitting device can be manufactured as follows.

First, as shown in FIG.
MOCVD (metal organic chemical vapor deposition) on As substrate 1
As a result, the n-type Al _h Ga _{1 -h} As clad layer 2, Al _i G
An a _{1 -i} As active layer 3, a p-type Al _h Ga _{1 -h} As clad layer 4, a p-type _Gn In _1-n P protective layer 5 and an n-type GaP current blocking layer 6 are sequentially grown.

Next, as shown in FIG. 1B, a current blocking layer 6 is formed in a circular shape by applying a resist 12 on the current blocking layer 6 and etching it.

Subsequently, as shown in FIG. 1C, the resist is removed, and p-type GaP current diffusion is performed by MOCVD over the current blocking layer 6 and the protective layer 5 where the current blocking layer 6 is not formed. The layer 7 is grown.

Thereafter, as shown in FIG. 1D, a p-type electrode 11 is provided on the current diffusion layer 7 and processed into a circular shape, and an n-type electrode 10 is provided on the substrate 1 side. Is completed.

In the thus obtained semiconductor light emitting device of the present embodiment, the current diffusion layer 7 is made of GaP containing no Al, so that it is
The following four improvement effects were obtained. As a first improvement effect, the GaP layer does not contain Al, and the crystallinity does not decrease due to oxidation of Al. Therefore, the reliability of the device can be greatly improved. As a second improvement effect, Al _i G
Even in the case of an infrared light-emitting element (emission wavelength: 830 nm) in which the Al composition i of the a _1-i As active layer 53 is 0.3, the band gap of the GaP layer is larger than the band gap of the active layer 3, so that current diffusion is performed. In the layer 7, the absorption of light emitted from the active layer 3 was small, and the light extraction efficiency was improved, so that a high-luminance semiconductor light emitting device could be obtained. As a third improvement effect, the GaP layer has a higher ionization rate of a p-type dopant such as Zn or Mg than the Al _g Ga _1-g As layer in which the Al composition g is 0.4 or more. The amount of the p-type dopant present was reduced, and the diffusion of the p-type dopant during the crystal growth was reduced, thereby greatly improving the device characteristics. As a fourth improvement effect, since a GaP layer can be provided with an electrode directly thereon, a GaAs contact layer as in a conventional semiconductor light emitting element is unnecessary, and the growth and etching steps of the contact layer are simplified. And realized a significant cost reduction.

When a voltage of 50 mA was applied to the semiconductor light emitting device of this embodiment by applying a voltage in the forward direction,
Light emission with a light output exceeding 1.8 mW was obtained at a peak wavelength of 830 nm. On the other hand, in the conventional semiconductor light emitting device, an optical output of only about 1 mW was obtained.

In this embodiment, each semiconductor layer is grown by MOCVD. However, MBE (molecular beam epitaxy), MOMBE (organic metal molecular beam epitaxy) or the like may be used.

(Embodiment 2) In Embodiment 2, instead of the n-type GaP current blocking layer of Embodiment 1, an n-type (Al _{v
Ga 1-v) 1-w} In w P (0 <v ≦ 1,0 ≦ w ≦ 1) semiconductor light-emitting device having a current blocking layer will be described.

FIG. 2 is a sectional view of the semiconductor light emitting device of the second embodiment.

In this semiconductor light emitting device, n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example, h = 0.50, Si carrier concentration 5 × 10 ¹⁷ cm ⁻³⁾ is formed on an n-type GaAs substrate 21. ) Cladding layer 22, Al _i Ga _1-i As (0 ≦ i ≦ 1, for example, i = 0.30) active layer 23 and p-type Al _h Ga _1-h As
(0 ≦ h ≦ 1, for example, h = 0.50, Zn carrier concentration 5 × 10 ¹⁷ cm ⁻³ ) A semiconductor multilayer structure including the cladding layer 24 is provided, and a p-type Ga _n In _1-n P ( 0 ≦ n
.Ltoreq.1, for example, n = 0) The protective layer 25 is provided. An n-type (Al _v Ga _{1 -v} ) _1-w In _w
P (0 <v ≦ 1, 0 ≦ w ≦ 1, for example, v = 0.20, w
= 0.50, Si carrier concentration 2 × 10 ¹⁸ cm ⁻³ ) The current blocking layer 26 is provided in a circular shape, and p is applied over the current blocking layer 26 and the protective layer 25 where the current blocking layer 26 is not formed. GaP (eg, Zn carrier concentration 5)
× 10 ¹⁸ cm ⁻³ ) A current diffusion layer 27 is provided. On the central portion of the current diffusion layer 27, a p-type electrode 211 is provided in a circular shape so as to face the current blocking layer 26, and the n-type substrate 2
On one side, an n-type electrode 210 is provided on the entire surface.

In the semiconductor light emitting device of this embodiment,
Current blocking layer 26 is _{(Al v Ga 1-v)} 1-w In w P (0 <v
≦ 1, 0 ≦ w ≦ 1), the use of an appropriate etchant causes a difference in the etching rate with respect to the GaInP protective layer 25. Therefore, selective etching is performed to simplify the manufacturing process and improve the yield. I was able to.

[0050] (Embodiment 3) In Embodiment 3, n-type Al _u G instead of n-type GaP current blocking layer of the first embodiment
A semiconductor light emitting device provided with a _1-u As (0 <u ≦ 1) current blocking layer will be described.

FIG. 3 shows a sectional view of the semiconductor light emitting device of the third embodiment.

In this semiconductor light emitting device, n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example, h = 0.30, Si carrier concentration 5 × 10 ¹⁷ cm ⁻³⁾ is formed on an n-type GaAs substrate 31. ) Cladding layer 32, Al _i Ga _1-i As (0 ≦ i ≦ 1, for example, i = 0.10) active layer 33 and p-type Al _h Ga _1-h As
(0 ≦ h ≦ 1, for example, h = 0.30, Zn carrier concentration 5 × 10 ¹⁷ cm ⁻³ ) A semiconductor multilayer structure including the cladding layer 34 is provided, and p-type _Gn In _1-n P ( 0 ≦ n
.Ltoreq.1, for example, n = 0) A protective layer 35 is provided. On the central portion of the protective layer 35, n-type Al _u Ga _1-u As (0 <u
≦ 1, for example, u = 0.30, Si carrier concentration 2 × 10
¹⁸ cm ⁻³ ) A current blocking layer 36 is provided in a circular shape, and p-type GaP (for example, Zn) is formed over the current blocking layer 36 and the protective layer 35 where the current blocking layer 36 is not formed.
Carrier concentration 5 × 10 ¹⁸ cm ⁻³ ) A current diffusion layer 37 is provided. A p-type electrode 311 is provided in a circular shape on the center of the current diffusion layer 37 so as to face the current blocking layer 36, and an n-type electrode 310 is provided on the entire surface of the n-type substrate 31.

In the semiconductor light emitting device of this embodiment,
Since the current blocking layer 36 is made of Al _u Ga _1-u As (0 <u ≦ 1), if an appropriate etchant is used, there will be a difference in the etching rate with the GaInP protective layer 35. 2 can be made larger than the AlGaInP current blocking layer, so that selective etching can be performed more reliably to simplify the manufacturing process and improve the yield.

(Embodiment 4) In this embodiment 4, Ga
An AlGaInAs-based light emitting diode provided with a P current diffusion layer will be described.

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

This semiconductor light emitting device has an n-type GaAs substrate 41 on an n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example, h = 0.30, Si carrier concentration 5 × 10 ¹⁷ cm ^−3). ) Cladding layer 42, (Al _j Ga _1-j ) _1-k In _k As (0 ≦ j
≦ 1,0 ≦ k ≦ 1, for example, j = 0, k = 0.80) active layer 43 and p-type _{Al h Ga 1-h As (} 0 ≦ h ≦ 1, for example, h = 0.30, Zn carrier concentration 5 × 10 ¹⁷ cm ^-3 )
The semiconductor multilayer structure composed of the cladding layer 44 is provided, p-type _{Ga n In 1-n P (} 0 ≦ n ≦ 1 thereon, for example, n =
0.50) A protective layer 45 is provided. An n-type (Al _v Ga _1-v ) _1-w In _w P (0 ≦ v) is formed on the central portion of the protective layer 45.
≦ 1, 0 ≦ w ≦ 1, for example, v = 0.70, w = 0.5
0, Si carrier concentration 2 × 10 ¹⁸ cm ⁻³ ) Current blocking layer 4
6, a p-type GaP (for example, a Zn carrier concentration of 5 × 10 ¹⁸⁾ is formed over the current blocking layer 46 and over the protective layer 45 where the current blocking layer 46 is not formed.
cm ⁻³ ) The current diffusion layer 47 is provided. A p-type electrode 411 is provided in a circular shape on the center of the current diffusion layer 47 so as to face the current blocking layer 46, and an n-type electrode 410 is provided on the entire surface of the n-type substrate 41.

In the semiconductor light emitting device of this embodiment,
Since the current diffusion layer 47 is made of GaP,
The band gap can be sufficiently increased even with respect to the active layer 43 made of an s-based material, the light emission from the active layer 43 is not absorbed in the current diffusion layer 47, and the light extraction efficiency is improved to increase the brightness. Was obtained.

When a voltage of 50 mA was applied to the semiconductor light emitting device of this embodiment by applying a voltage in the forward direction,
Light emission with a light output exceeding 1.2 mW was obtained at a peak wavelength of 980 nm. On the other hand, in the conventional semiconductor light emitting device, an optical output of only about 0.5 mW was obtained.

(Embodiment 5) In Embodiment 5, a semiconductor light emitting device in which the current diffusion layer of Embodiment 1 has a two-layer structure and a current blocking layer is provided between them will be described.

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

In this semiconductor light emitting device, n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example, h = 0.30, Si carrier concentration 5 × 10 ¹⁷ cm ⁻³⁾ is formed on an n-type GaAs substrate 51. )
Cladding layer 52, Al _i Ga _1-i As (0 ≦ i ≦ 1, for example, i = 0.10) active layer 53 and p-type Al _h Ga _1-h A
s (0 ≦ h ≦ 1, for example, h = 0.30, Zn carrier concentration of 5 × 10 ¹⁷ cm ⁻³ ) A semiconductor multilayer structure including a cladding layer 54 is provided, and p-type GaP (for example, Zn carrier concentration of 5 × 10 ¹⁸ cm ⁻³ ) First current diffusion layer 57 a and p-type _Gn In _1-n P (0 ≦ n ≦ 1, for example, n = 0.
50) A protective layer 55 is provided. An n-type (Al _v Ga _{1 -v} ) _1-w In _w P (0 ≦ v ≦
1, 0 ≦ w ≦ 1, for example, v = 0.70, w = 0.50,
Si carrier concentration 2 × 10 ¹⁸ cm ⁻³ ) A current blocking layer 56 is provided in a circular shape, and p-type GaP (for example, Zn) is formed over the current blocking layer 56 and the protective layer 55 where the current blocking layer 56 is not formed. Carrier concentration 5 × 10 ¹⁸ cm
^-3 ) The second current diffusion layer 57b is provided. A p-type electrode 511 is provided in a circular shape on the center of the second current diffusion layer 57b so as to face the current blocking layer 56, and the n-type substrate 5
On one side, an n-type electrode 510 is provided on the entire surface.

In the semiconductor light emitting device of this embodiment,
Since the current blocking layer 56 is provided between the current spreading layers 57a and 57b having the two-layer structure, the current spread to the peripheral portion of the current blocking layer 56 in the second current spreading layer 57b is reduced by the first current spreading. The light was further expanded in the layer 57a and efficiently guided to the active layer 53 in a wide area other than immediately below the p-type electrode 511, and the light-emitting area was expanded to further improve the light extraction efficiency.

When a voltage of 50 mA was applied to the semiconductor light emitting device of this embodiment in the forward direction to apply a voltage,
Light emission with a light output exceeding 2.0 mW was obtained at a peak wavelength of 850 nm. On the other hand, in the conventional semiconductor light emitting device, an optical output of only about 1.0 mW was obtained.

(Embodiment 6) In this embodiment 6, a p-type current blocking layer having a two-layer structure is provided in place of the n-type current blocking layer of the first embodiment, and the hetero barrier in the formation region is made higher than the hetero barrier in the non-formation region. A semiconductor light emitting device having a larger size will be described.

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

In this semiconductor light emitting device, an n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example, h = 0.50, a Si carrier concentration of 5 × 10 ¹⁷ cm ⁻³⁾ is formed on an n-type GaAs substrate 61. 3.) Cladding layer 62, Al _i Ga _1-i As (0 ≦ i ≦ 1, for example i = 0.30) active layer 63 and p-type Al _h Ga _1-h As
(0 ≦ h ≦ 1, for example, h = 0.50, Zn carrier concentration 5 × 10 ¹⁷ cm ⁻³ ) A semiconductor multilayer structure including the cladding layer 64 is provided, and p-type GaAs (for example, Zn carrier concentration 1 × 10 ¹⁷ cm ⁻³ ) First current blocking layer 6
6 and p-type (Al _v Ga _1-v ) _1-w In _w P (0 ≦ v ≦
1, 0 ≦ w ≦ 1, for example, v = 0.70, w = 0.50,
Zn carrier concentration 1 × 10 ¹⁷ cm ⁻³ ) Second current blocking layer 6
8 is provided in a circular shape, and a p-type GaP (for example, Zn carrier concentration of 5 × 10 ¹⁸ cm ⁻³ ) current is formed over the current blocking layers 66 and 68 and over the semiconductor laminated structure where the current blocking layers 66 and 68 are not formed. A diffusion layer 67 is provided. On the central part of the current diffusion layer 67, the current blocking layers 66, 6
A p-type electrode 611 is provided in a circular shape so as to face 8, and an n-type electrode 610 is provided on the entire surface of the n-type substrate 61.

In the semiconductor light emitting device of this embodiment,
The current blocking layer is composed of the GaAs first current blocking layer 66 and AlGaI.
Since it is composed of a heterojunction with the nP second current blocking layer 68,
In the region where the current blocking layer is formed, a large band discontinuity (heterobarrier) occurs on the valence band side. This heterobarrier
AlGaAs in a region where no current blocking layer is formed
It is larger than the hetero barrier between the s second cladding layer 64 and the GaP current diffusion layer 67, and the injected current is efficiently guided to the region where the current blocking layers 66 and 68 are not formed. Light emission was obtained in the active layer 63 in the region, and the light extraction efficiency was improved, so that a high-luminance semiconductor light emitting device could be obtained. Further, in the semiconductor light emitting device of the present embodiment, the current blocking layers 66 and 68 are both p
Since it is a type, all of the crystals on the light emitting portion can be of the same conductivity type, the manufacturing process can be simplified, and the re-diffusion of impurities of the opposite conductivity type can be prevented from adversely affecting the element characteristics. Was.

(Embodiment 7) In Embodiment 7, instead of providing a p-type current blocking layer having a two-layer structure of Embodiment 6, p
A semiconductor light emitting device in which the hetero barrier between the type current blocking layer and the protective layer thereunder is increased will be described.

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

This semiconductor light emitting device has an n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example, h = 0.50, a Si carrier concentration of 5 × 10 ¹⁷ cm ⁻³⁾ on an n-type GaAs substrate 71. ) Cladding layer 72, Al _i Ga _1-i As (0 ≦ i ≦ 1, for example, i = 0.30) active layer 73 and p-type Al _h Ga _1-h As
(0 ≦ h ≦ 1, for example, h = 0.50, Zn carrier concentration 5 × 10 ¹⁷ cm ⁻³ ) A semiconductor multilayer structure including the cladding layer 74 is provided, and p-type Al _m Ga _1- mAs ( 0 ≦
(m ≦ 1, for example, m = 0.10) A protective layer 75 is provided. On the center of the protective layer 75, p-type Al _u Ga _1-u As
(0 ≦ u ≦ 1, for example, u = 0.40, Zn carrier concentration 1 × 10 ¹⁷ cm ⁻³ ) The current blocking layer 76 is provided in a circular shape, and the current blocking layer 76 and the current blocking layer 76 are formed. P-type GaP over the unprotected protective layer 75
(For example, Zn carrier concentration of 5 × 10 ¹⁸ cm ⁻³ ) The current diffusion layer 77 is provided. A p-type electrode 711 is provided in a circular shape on the center of the current diffusion layer 77 so as to face the current blocking layer 76, and an n-type electrode 710 is provided on the entire surface of the n-type substrate 71.

In the semiconductor light emitting device of this embodiment, in the region where the current blocking layer is formed, the AlGaAs current blocking layer 76 is formed.
A large band discontinuity (heterobarrier) occurs on the valence band side due to the heterojunction between AlGaP and the AlGaP protective layer 75.
This heterobarrier serves as an AlGaP protective layer 75 and a GaP current diffusion layer 7 in a region where a current blocking layer is not formed.
7, the injected current is spread to a region where the current blocking layer 76 is not formed, so that light emission can be obtained in the active layer 73 in a wide region other than immediately below the electrode, and light extraction efficiency Was improved, and a high-luminance semiconductor light emitting device was obtained. Further, in the semiconductor light emitting device of this embodiment, since the current blocking layer 76 is of the p-type, all the crystals on the light emitting portion can be of the same conductivity type. It was also possible to prevent the re-diffusion of the impurities from adversely affecting the device characteristics.

(Embodiment 8) In Embodiment 8, a semiconductor light emitting device in which the current diffusion layer of Embodiment 6 has a two-layer structure and a current blocking layer is provided between them will be described.

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

This semiconductor light emitting device has an n-type GaAs substrate 81 on an n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example, h = 0.30, Si carrier concentration 5 × 10 ¹⁷ cm ^−3). ) Cladding layer 82, Al _i Ga _{1 -i} As (0 ≦ i ≦ 1, e.g., i = 0) active layer 83 and p-type Al _h Ga _{1 -h} As (0 ≦
h ≦ 1, for example, h = 0.30, Zn carrier concentration 5 × 1
0 ¹⁷ cm ⁻³ ) is provided with a semiconductor laminated structure composed of a cladding layer 84, on which a first current diffusion layer 87 a of p-type GaP (for example, a Zn carrier concentration of 5 × 10 ¹⁸ cm ⁻³ ) is provided. P-type GaAs on its central portion (e.g. Zn carrier concentration of 1 × 10 ¹⁷ cm ^-3) the first current blocking layer 86 and the p-type _{(Al v Ga 1-v)} 1-w In w P (0 ≦ v ≦ 1 , 0 ≦ w
≦ 1, for example, v = 0.70, w = 0.50, Zn carrier concentration 1 × 10 ¹⁷ cm ⁻³ ) The second current blocking layer 88 is provided in a circular shape, and the second current blocking layer 88 and the current A p-type GaP (for example, with a Zn carrier concentration of 5 × 10 5) over the semiconductor stacked structure where the blocking layers 86 and 88 are not formed.
¹⁸ cm ^-3 ) The second current diffusion layer 87b is provided. The current blocking layers 86 and 8 are provided on the central portion of the second current spreading layer 87b.
A p-type electrode 811 is provided in a circular shape so as to be opposed to 8, 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,
In addition to the effects described in the sixth embodiment, since the current blocking layers 86 and 88 are provided between the current spreading layers 87a and 87b having the two-layer structure, the current blocking layers 86 and 88 are provided in the second current spreading layer 87b. The current spread to the periphery of 88 is further spread in the first current diffusion layer 87a and efficiently guided to the active layer 83 in a wide area other than immediately below the p-type electrode 811, and the light emitting area is expanded to extract light. Efficiency could be further improved.

Ninth Embodiment In a ninth embodiment, a semiconductor light emitting device in which a high-resistance current blocking layer is provided instead of the n-type current blocking layer of the first embodiment will be described.

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

This semiconductor light emitting device has n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example h = 0.70, Si carrier concentration 5 × 10 ¹⁷ cm ⁻³⁾ on an n-type GaAs substrate 91. ) Cladding layer 92, Al _i Ga _1-i As (0 ≦ i ≦ 1, for example, i = 0.50) active layer 93 and p-type Al _h Ga _1-h As
(0 ≦ h ≦ 1, for example, h = 0.70, Zn carrier concentration of 5 × 10 ¹⁷ cm ^-3) semiconductor multilayer structure composed of the cladding layer 94 is provided, p-type Ga _n In _1-n P thereon ( 0 ≦ n
.Ltoreq.1, for example, n = 0.50) A protective layer 95 is provided. (Al _v Ga _1-v ) _1-w I
n _w P (0 ≦ v ≦ 1, 0 ≦ w ≦ 1, for example, v = 0, w =
0) A current blocking layer 96 is provided in a circular shape, and p-type GaP (for example, a Zn carrier concentration of 5 × 10 ¹⁸ cm ⁻³⁾ is formed over the current blocking layer 96 and over the protective layer 95 where the current blocking layer 96 is not formed. ) A current diffusion layer 97 is provided. A p-type electrode 911 is provided in a circular shape on the center of the current diffusion layer 97 so as to face the current blocking layer 96.
On the mold substrate 91 side, an n-type electrode 910 is provided on the entire surface.

As a method of forming a high-resistance current blocking layer, there are, for example, a method of not doping an impurity and a method of doping an impurity which easily forms a deep level. Can grow. In the present embodiment, the growth temperature is set to 600 ° C. without doping the impurity, so that the high-resistance current blocking layer 9 is formed.
6 grew.

In the semiconductor light emitting device of this embodiment,
By providing the high resistance current blocking layer 96,
Since the injected current is spread to a region where the current blocking layer 96 is not formed, light emission can be obtained in the active layer 93 in a wide region other than immediately below the electrode, and a high-brightness semiconductor light emitting device can be obtained by improving light extraction efficiency. And could be. Further, in the semiconductor light emitting device of the present embodiment, it is not necessary to control the conductivity type and carrier concentration of the current blocking layer 96, so that the manufacturing process can be simplified.

(Embodiment 10) In this embodiment 10,
A semiconductor light emitting device according to the ninth embodiment in which the current diffusion layer has a two-layer structure and a current blocking layer is provided between them will be described.

FIG. 10 is a sectional view of the semiconductor light emitting device of the tenth embodiment.

In this semiconductor light emitting device, n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example, h = 0.50, Si carrier concentration 5 × 10 ¹⁷ cm ⁻³⁾ is formed on an n-type GaAs substrate 101. )
Cladding layer 102, Al _i Ga _1-i As (0 ≦ i ≦ 1, for example, i = 0.30) active layer 113 and p-type Al _h Ga
_A semiconductor laminated structure including a _1-h As (0 ≦ h ≦ 1, for example, h = 0.50, Zn carrier concentration of 5 × 10 ¹⁷ cm ⁻³ ) cladding layer 104 is provided, and a p-type GaP (for example, Zn A carrier concentration of 5 × 10 ¹⁸ cm ⁻³ ) a first current diffusion layer 107 a and a p-type _Gn In _1-n P (0 ≦ n ≦ 1, for example, n = 0.50) protection layer 105 are provided. (Al _v Ga _{1 -v} ) _{1 -w} In _w P
(0 ≦ v ≦ 1, 0 ≦ w ≦ 1, for example, v = 0, w = 0) The current blocking layer 106 is provided in a circular shape, and the current blocking layer 1
A second p-type GaP (for example, Zn carrier concentration of 5 × 10 ¹⁸ cm ⁻³ ) second current diffusion layer 107b is provided on the surface of the protective layer 105 on which the current blocking layer 106 is not formed. A p-type electrode 1011 is provided on the central portion of the second current diffusion layer 107b so as to face the current blocking layer 106.
Are provided in a circular shape, and an n-type electrode 1 is provided on the n-type substrate 101 side.
010 is provided on the entire surface.

In the semiconductor light emitting device of this embodiment,
In addition to the effects of the ninth embodiment, the current diffusion layer 10 having a two-layer structure
7a and 107b, the current blocking layer 106 is provided between the second current spreading layer 107b and the current blocking layer 106.
Current spread to the periphery of the first current diffusion layer 107
a, the light was efficiently guided to the active layer 103 in a wide area other than immediately below the p-type electrode 1011, and the light-emitting area could be expanded to further improve the light extraction efficiency.

(Eleventh Embodiment) In the eleventh embodiment,
Instead of the GaP current diffusion layer of Embodiment 1, Zn _a Mg _1-a
A description will be given of a semiconductor light emitting device provided with a current diffusion layer of S _1-b Se _b (0 ≦ a ≦ 1, 0 ≦ b ≦ 1).

FIG. 11 is a sectional view of a semiconductor light emitting device according to the eleventh embodiment.

This semiconductor light emitting device has an n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example, h = 0.70, a Si carrier concentration of 5 × 10 ¹⁷ cm ⁻³⁾ on an n-type GaAs substrate 111. )
Cladding layer 112, Al _i Ga _1-i As (0 ≦ i ≦ 1, for example, i = 0.50) active layer 113 and p-type Al _h Ga
_A semiconductor laminated structure including a _1-h As (0 ≦ h ≦ 1, for example, h = 0.70, Zn carrier concentration 5 × 10 ¹⁷ cm ⁻³ ) cladding layer 114 is provided, and a p-type (Zn _d Mg
_{1-d) S 1-e} Se e (0 ≦ d ≦ 1,0 ≦ e ≦ 1, for example, d
= 0.85, e = 0.85, Zn carrier concentration 5 × 10
¹⁷ cm ^-3 ) The protective layer 115 is provided. Protective layer 11
N-type on the central portion of the _{5 (Zn r Mg 1-r} ) S 1-z Se z (0
≦ r ≦ 1, 0 ≦ z ≦ 1, for example, r = 0.85, z = 0.
85, Si carrier concentration 2 × 10 ¹⁸ cm ⁻³ ) A current blocking layer 116 is provided in a circular shape, and a protective layer 115 on the current blocking layer 116 and on which the current blocking layer 116 is not formed.
P-type Zn _a Mg _1-a S _1-b Se _b (0 ≦ a
≦ 1, 0 ≦ b ≦ 1, for example, a = 0.85, b = 0.8
5. Zn carrier concentration 1 × 10 ¹⁸ cm ⁻³ ) Current diffusion layer 1
17 are provided. A p-type electrode 1111 is provided in a circular shape on a central portion of the current diffusion layer 117 via a p-type ZnTe (for example, Zn carrier concentration of 1 × 10 ¹⁸ cm ⁻³ ) contact layer 119 so as to face the current blocking layer 116. And
On the n-type substrate 111 side, an n-type electrode 1110 is provided on the entire surface.

In the semiconductor light emitting device of this embodiment,
Zn _a Mg _1-a S _{1-b in which the} current diffusion layer 117 does not contain Al
Since Se _b (0 ≦ a ≦ 1, 0 ≦ b ≦ 1), Ga
Similar to the P layer, Al does not oxidize, and can prevent deterioration of device characteristics such as deterioration of crystallinity and light absorption due to formation of deep levels, and significant reduction in luminance under high temperature and high humidity conditions. Could be improved. Also, Zn _a Mg _1-a S _1-b Se
_{The b} (0 ≦ a ≦ 1, 0 ≦ b ≦ 1) layer can have a larger band gap than the GaP layer depending on its composition, and therefore, the absorption of light from the light emitting portion by the current diffusion layer can be further reduced. As a result, the light extraction efficiency was improved, and a high-luminance semiconductor light emitting device was obtained. Furthermore, Zn _a
Mg _1-a S _1-b Se _b (0 ≦ a ≦ 1, 0 ≦ b ≦ 1) layer
Since the lattice matching between the GaAs substrate and the light emitting unit was possible, the light emitting unit was allowed to emit light with high luminous efficiency without adversely affecting the light emitting unit.

(Twelfth Embodiment) In the twelfth embodiment,
Ga _1-c In c instead of GaP current spreading layer embodiments 1
N (0 ≦ c ≦ 1) current diffusion layer or (Al _s Ga _1-s )
_{1-t In t N (0} <s ≦ 0.3,0 ≦ t ≦ 1) semiconductor light-emitting device having a current diffusion layer is described.

FIG. 12 is a sectional view of a semiconductor light emitting device according to the twelfth embodiment.

This semiconductor light emitting device has an n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example, h = 0.50, a Si carrier concentration of 5 × 10 ¹⁷ cm ⁻³⁾ on an n-type GaAs substrate 121. )
Cladding layer 122, Al _i Ga _1-i As (0 ≦ i ≦ 1, for example, i = 0.30) active layer 123 and p-type Al _h Ga
_1-h As (0 ≦ h ≦ 1, for example, h = 0.50, Zn carrier concentration 5 × 10 ¹⁷ cm ⁻³ ), a semiconductor multilayer structure including a cladding layer 124 is provided, and p-type Ga _A In _{1 1} is formed thereon. _-A
An N (0 ≦ A ≦ 1, for example, A = 0) protective layer 125 is provided. On the center of the protective layer 125, an n-type Ga _1- BI
_{n B N (0 ≦ B ≦} 1, for example, B = 0.10, Si carrier concentration 2 × 10 ¹⁸ cm ^-3) current blocking layer 126 is provided in a circular shape, the current blocking layer 126 and on the current blocking layer 1
P-type _{Ga 1-c In c N (} 0 ≦ c ≦ 1 over the protective layer 125 portions 26 are not formed, for example, c = 0, Zn
(Carrier concentration: 1 × 10 ¹⁸ cm ⁻³ ) A current diffusion layer 127 is provided. A p-type electrode 1211 is provided in a circular shape on the center of the current diffusion layer 127 so as to face the current blocking layer 126, and an n-type electrode 1210 is provided on the entire surface of the n-type substrate 121.

In the semiconductor light emitting device of this embodiment,
Current spreading layer 127 does not contain _{Al Ga 1-c In c N} (0
.Ltoreq.c.ltoreq.1), oxidation of Al does not occur as in the case of the GaP layer, and it is possible to prevent deterioration of device characteristics such as deterioration of crystallinity and light absorption due to formation of deep levels. The decrease in luminance under the conditions was also significantly improved. _{Also, Ga 1-c In c N} (0 ≦ c ≦ 1) layer, it is possible to increase the further bandgap than GaP layer by the composition, the absorption of light from the light emitting portion due to current spreading layer further As a result, the light extraction efficiency was improved, and a high-brightness semiconductor light emitting device was obtained. Furthermore, G
_{a 1-c In c N (} 0 ≦ c ≦ 1) layer, it is possible to provide a direct electrode thereon, a contact layer, such as a conventional semiconductor light emitting element is required, with less manufacturing steps Significant cost reduction was realized.

In the semiconductor light emitting device of this embodiment, (Al _s G
_{a 1-s) 1-t} In t N (0 <s ≦ 0.3,0 ≦ t ≦ 1) the case of providing a current spreading layer, the current diffusion layer because Al composition is 0.3 or less hardly oxidized No device characteristics were degraded. _{Further, (Al s Ga 1-s} ) 1-t In t N (0 <s ≦
The 0.3, 0 ≦ t ≦ 1) layer can have a larger band gap than the GaP layer even if the Al composition is 0.3 or less, so that the current diffusion layer absorbs light from the light emitting portion. To further improve light extraction efficiency,
A high-brightness semiconductor light emitting device was obtained. further,
_{(Al s Ga 1-s)} 1-t In t N (0 <s ≦ 0.3,0 ≦ t
.Ltoreq.1) Since an electrode can be provided directly on the layer, a contact layer as in a conventional semiconductor light emitting element is unnecessary, and the number of manufacturing steps can be reduced to realize a significant cost reduction.

(Thirteenth Embodiment) In the thirteenth embodiment,
Instead of the GaP current diffusion layer of the first embodiment, (Al _x Ga
_{1-x) 1-y In} y P (0 <x ≦ 0.3,0 ≦ y ≦ 1) semiconductor light-emitting device having a current diffusion layer is described.

This semiconductor light emitting device has an n-type GaAs substrate 131 on which n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example, h = 0.50, and a Si carrier concentration of 5 × 10 ¹⁷ cm ^−3). )
Cladding layer 132, Al _i Ga _1-i As (0 ≦ i ≦ 1, for example, i = 0.30) active layer 133 and p-type Al _h Ga
_A semiconductor multilayer structure including a _1-h As (0 ≦ h ≦ 1, for example, h = 0.50, Zn carrier concentration 5 × 10 ¹⁷ cm ⁻³ ) cladding layer 134 is provided, and a p-type _Gn In ₁ is formed thereon. _-n
A P (0 ≦ n ≦ 1, for example, n = 0) protective layer 135 is provided. An n-type GaP (for example, a Si carrier concentration of 2 × 10 ¹⁸ cm ⁻³ ) current blocking layer 1 is formed on the central portion of the protective layer 135.
36 is provided in a circular shape, and the p-type (Al _x Ga _1-x ) _1-y In _y P (0 <) is formed over the current blocking layer 136 and the protective layer 135 where the current blocking layer 136 is not formed.
x ≦ 0.3, 0 ≦ y ≦ 1, for example x = 0.1, y = 0.
1. Zn carrier concentration 5 × 10 ¹⁸ cm ⁻³ ) Current diffusion layer 1
37 are provided. A p-type electrode 1311 is provided on the center of the current diffusion layer 137 in a circular shape via a p-type GaAs (for example, Zn carrier concentration of 5 × 10 ¹⁸ cm ⁻³ ) contact layer 139 so as to face the current blocking layer 136. And
On the n-type substrate 131 side, an n-type electrode 1310 is provided on the entire surface.

In the semiconductor light emitting device of this embodiment,
The current diffusion layer 137 has an Al composition of 0.3 or less (Al _x G
a _1-x ) _1-y In _y P (0 <x ≦ 0.3, 0 ≦ y ≦ 1), the current diffusion layer was hardly oxidized, and the device characteristics did not deteriorate. Also, (Al _x Ga _1-x ) _1-y In _y P
The (0 <x ≦ 0.3, 0 ≦ y ≦ 1) layer has an Al composition of 0.2.
Since the band gap can be made larger than that of the GaP layer even when the thickness is 3 or less, the light absorption efficiency from the light emitting portion by the current diffusion layer is further reduced to improve the light extraction efficiency, and the semiconductor light emitting device of high brightness Could be obtained. Further, (Al _x Ga _{1 -x} ) _{1 -y} In _y P (0 <x ≦ 0.3, 0
≦ y ≦ 1) layer can be lattice-matched with the GaAs substrate and the light emitting section, so that no adverse effect on the light emitting section occurs.
It was possible to emit light with high luminous efficiency.

(Embodiment 14) In this embodiment 14,
Instead of the GaP current diffusion layer of the first embodiment, (Al _p Ga
_{1-p) 1-q In} q As (0 <p ≦ 0.3,0 ≦ q ≦ 1) semiconductor light-emitting device having a current diffusion layer is described.

In this semiconductor light emitting device, an n-type Al _h Ga _{1 -h} As (0 ≦ h ≦ 1, for example, h = 0.30, a Si carrier concentration of 5 × 10 ¹⁷ cm ⁻³⁾ is formed on an n-type GaAs substrate 141. )
Cladding layer 142, (Al _j Ga _1-j ) _1-k In _k As (0
≦ j ≦ 1, 0 ≦ k ≦ 1, for example, j = 0, k = 0.90)
The active layer 143 and the p-type Al _h Ga _1-h As (0 ≦ h ≦
1, for example, h = 0.30, Zn carrier concentration 5 × 10 ¹⁷
cm ⁻³ ) A semiconductor multilayer structure including a cladding layer 144 is provided, and a p-type (Al _D Ga _{1 -D} ) ₁ -E _InE As is provided thereon.
(0 ≦ D ≦ 1, 0 ≦ E ≦ 1, for example, D = 0, E = 0.8
0) A protective layer 145 is provided. N-type on the central portion of the protective layer _{145 (Al F Ga 1-F} ) 1-G In G As (0 ≦ F
≦ 1,0 ≦ G ≦ 1, for example, F = 0, G = 0.80, for example, Si carrier concentration 2 × 10 ¹⁸ cm ^-3) current blocking layer 14
6 is provided in a circular shape, and the p-type (Al _p Ga _1-p ) _{1-q Inq} As (0 <) is formed over the current blocking layer 146 and the protective layer 145 where the current blocking layer 146 is not formed.
p ≦ 0.3, 0 ≦ q ≦ 1, for example, p = 0.1, q = 0.
80, Zn carrier concentration 5 × 10 ¹⁸ cm ⁻³ ) A current diffusion layer 147 is provided. A p-type GaAs is formed on the central portion of the current diffusion layer 147 so as to face the current blocking layer 146.
(For example, Zn carrier concentration 5 × 10 ¹⁸ cm ⁻³ ) A p-type electrode 1411 is provided in a circular shape via a contact layer 149, and an n-type electrode 1410 is provided on the entire surface of the n-type substrate 141.

In the semiconductor light emitting device of this embodiment,
The current diffusion layer 147 has an Al composition of 0.3 or less (Al _p G
a _1-p ) _1-q In _q As (0 <p ≦ 0.3, 0 ≦ q ≦ 1)
, The current diffusion layer was hardly oxidized, and the device characteristics did not deteriorate. Also, (Al _p Ga _1-p ) _{1-q Inq} A
The s (0 <p ≦ 0.3, 0 ≦ q ≦ 1) layer can have a band gap larger than that of the GaP layer even when the Al composition is 0.3 or less. The light extraction efficiency was further reduced by further reducing the absorption of light from the substrate, and a high-brightness semiconductor light emitting device was obtained.

Note that the present invention is not limited to the above embodiments, and various modifications are possible. For example, the n-type clad layer, the active layer, the p-type clad layer, and the protective layer may be made of other materials, and the composition may be appropriately changed.

The current spreading layer has a larger band gap than the active layer and does not contain Al or has an Al composition of 0.3.
Other materials may be used as long as they are the following compound semiconductors, and the composition may be appropriately changed.

The current blocking layer preferably has a band gap larger than that of the active layer. However, the present invention is not limited to this. A material having the same band gap as the active layer or a material smaller than the active layer may be used. The composition may be appropriately changed.

In the above embodiment, each semiconductor layer is grown on an n-type substrate, but a p-type substrate may be used. In this case, the conductivity type of each semiconductor layer may be reversed.

In the above embodiment, the circular current blocking layer is provided on the central portion of the semiconductor laminated structure. However, the current blocking layer may be formed on a part of the semiconductor laminated structure.
For example, it may be provided on both ends of the semiconductor multilayer structure, or may be provided so as to surround the center of the semiconductor multilayer structure.

Further, in the above embodiment, the semiconductor light emitting device using the double hetero junction structure in which the active layer is provided between the p-type cladding layer and the n-type cladding layer has been described. The present invention can be applied to a semiconductor light emitting device having a structure.

[0106]

As described in detail above, according to the present invention,
Light emission in a wide area other than immediately below the electrodes can be realized, and a high-luminance semiconductor light-emitting element with improved light extraction efficiency can be obtained.
Further, since the current diffusion layer is made of a compound semiconductor having a large band gap, light from the light emitting portion is not absorbed by the current diffusion layer, and a high-brightness semiconductor light emitting device can be obtained. Further, the current spreading layer does not contain Al, or A
Since the semiconductor is composed of a compound semiconductor having a composition greater than 0 and 0.3 or less, the current diffusion layer is oxidized, the light is absorbed by the current diffusion layer, and the current diffusion is performed, as in a conventional semiconductor light emitting device using an AlGaAs current diffusion layer. Diffusion of the p-type dopant contained in the layer does not occur, and the reliability can be improved. Further, since the current blocking layer is partially provided between the semiconductor laminated structure and the current diffusion layer, the luminous efficiency in a region other than immediately below the electrode is further improved.

When the current diffusion layer is formed as two layers and a current blocking layer is partially provided therebetween, the current spreads to a region where the current blocking layer is not formed in the current diffusion layer on the light extraction electrode side. In addition, since the current is spread in the current diffusion layer on the substrate side, light emission can be obtained in a wider area.

The current blocking layer may be made of a first conductivity type compound semiconductor or a high resistance material. In particular, when the current blocking layer is made of a high resistance material,
Since there is no need to control the conductivity type of the current blocking layer or control the carrier concentration of the current blocking layer, it is possible to simplify the manufacturing process and prevent adverse effects due to re-diffusion of impurities. Further, as the current blocking layer, a compound semiconductor layer of the second conductivity type, in which the current blocking layer is formed so that the hetero barrier in the formation region is larger than the hetero barrier in the non-formation region, can be used. In this case, since all the crystals on the light emitting portion have the same conductivity type,
The manufacturing process is simplified, and adverse effects due to re-diffusion of impurities of the opposite conductivity type can be prevented.

In the case where a GaP layer is used as the current diffusion layer, since Al is not contained, deterioration of device characteristics due to its oxidation does not occur, and reliability can be greatly improved. In addition, the GaP layer has a larger band gap than the AlGaAs layer used in the conventional semiconductor light emitting device, and can reduce the absorption of light from the light emitting portion by the current diffusion layer. It is possible to obtain a high-brightness semiconductor light-emitting element by improving. G
The aP layer is made of Al _g Ga _1-g having an Al composition g of 0.4 or more.
Since the ionization rate of the p-type dopant is higher than that of the As layer,
The p-type dopant diffused during the crystal growth can be prevented from adversely affecting the device characteristics. Further, since the GaP layer can be provided with an electrode directly thereon, a contact layer such as a conventional semiconductor light emitting device is not required,
Significant cost reduction can be realized by reducing the number of manufacturing steps.

As the current diffusion layer, Zn _a Mg _1-a S _1-b
When the Se _b (0 ≦ a ≦ 1, 0 ≦ b ≦ 1) layer is used, G
Since it does not contain Al as in the case of the aP layer, the device characteristics do not deteriorate due to its oxidation, and the reliability can be greatly improved. Also, Zn _a Mg _1-a S _1-b Se _b (0 ≦ a ≦ 1,
The 0 ≦ b ≦ 1) layer can further increase the band gap compared to the GaP layer, so that the absorption of light from the light emitting portion by the current diffusion layer can be further reduced to obtain a high-luminance semiconductor light emitting device. it can. Further, Zn _a Mg _1-a S
_{Since the 1-b} Se _b (0 ≦ a ≦ 1, 0 ≦ b ≦ 1) layer can be lattice-matched with the GaAs substrate and the light emitting unit, it does not adversely affect the light emitting unit.

[0111] _{Ga 1-c In c N (} 0 as the current diffusion layer
≦ c ≦ 1) When the layer is used, it does not contain Al as in the case of the GaP layer.
The reliability can be greatly improved. Ga _{1-c
In c N (0 ≦ c ≦} 1) layer, it is possible to increase further the bandgap than GaP layer, further reduced by high-intensity semiconductor light-emitting element absorption of light from the light emitting portion due to current spreading layer Can be obtained. Further, Ga
_{1-c In c N (0} ≦ c ≦ 1) layer, it is possible to provide a direct electrode thereon, a contact layer, such as a conventional semiconductor light emitting element is not required, greatly reduces the manufacturing process Cost reduction can be realized.

As the current diffusion layer, (Al _x Ga _{1 -x} )
_{When a 1-y} In _y P (0 <x ≦ 0.3, 0 ≦ y ≦ 1) layer is used, the current diffusion layer is hardly oxidized and the reliability does not decrease because the Al composition is 0.3 or less. . Also, (Al _x G
a _1-x ) _1-y In _y P (0 <x ≦ 0.3, 0 ≦ y ≦ 1) layer has a band gap larger than that of the light emitting portion even when the Al composition is 0.3 or less. It is possible to reduce the absorption of light from the light emitting portion by the current diffusion layer, so that it is possible to improve the light extraction efficiency and obtain a high-luminance semiconductor light emitting device. Furthermore, (Al _x Ga _1-x ) _1-y In _y
Since the P (0 <x ≦ 0.3, 0 ≦ y ≦ 1) layer can be lattice-matched with the GaAs substrate and the light emitting unit, no adverse effect is exerted on the light emitting unit.

As the current diffusion layer, (Al _s Ga _{1 -s} )
_1-t In _t N when using a (0 <s ≦ 0.3,0 ≦ t ≦ 1) layer, hardly current diffusion layer is oxidized so Al composition is 0.3 or less, it is not reduced reliability . In addition, (Al _s G
_{a 1-s) 1-t} In t N (0 <s ≦ 0.3,0 ≦ t ≦ 1) layer, even Al composition 0.3 or less have been used in the conventional semiconductor light emitting element Since the band gap can be set larger than that of the AlGaAs layer, absorption of light from the light emitting portion by the current diffusion layer can be reduced. further,
_{(Al s Ga 1-s)} 1-t In t N (0 <s ≦ 0.3,0 ≦ t
.Ltoreq.1) Since an electrode can be provided directly on the layer, a contact layer as in a conventional semiconductor light emitting device is not required, and the number of manufacturing steps can be reduced to realize a significant cost reduction.

As the current diffusion layer, (Al _p Ga _{1 -p} )
_{When a 1-q} In _q As (0 <p ≦ 0.3, 0 ≦ q ≦ 1) layer is used, since the Al composition is 0.3 or less, the current diffusion layer is not easily oxidized and the reliability does not decrease. . Also, (Al _p
Ga _1-p ) _1-q In _q As (0 <p ≦ 0.3, 0 ≦ q ≦
1) Even if the Al composition is 0.3 or less, the band gap can be set to be larger than that of the light emitting portion, so that light absorption from the light emitting portion by the current diffusion layer can be reduced.

By providing a protective layer between the current blocking layer and the semiconductor laminated structure, it is possible to prevent the cladding layer made of a material containing Al from being exposed and oxidized before regrowth. In addition, if a protective layer made of a material that can be selectively etched with the current blocking layer is provided, the manufacturing process can be greatly simplified and a significant cost reduction can be realized.

As the light emitting portion, Al _i Ga _{1 -i} As (0 ≦
When the i <1) layer is used, a high-output semiconductor light-emitting device can be obtained in the infrared region in the 0.68 μm to 0.86 μm band. Further, (Al _j Ga _1-j ) _1-k In _k
When an As (0 ≦ j ≦ 1, 0 ≦ k ≦ 1) layer is used, 0.9
A high-output semiconductor light emitting device can be obtained in the infrared region of the band from 5 μm to 1.25 μm.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a manufacturing process of a semiconductor light emitting device of Embodiment 1.

FIG. 2 is a cross-sectional view illustrating a semiconductor light emitting device according to a second embodiment.

FIG. 3 is a cross-sectional view illustrating a semiconductor light emitting device according to a third embodiment.

FIG. 4 is a sectional view showing a semiconductor light emitting device according to a fourth embodiment.

FIG. 5 is a sectional view showing a semiconductor light emitting device of a fifth embodiment.

FIG. 6 is a cross-sectional view illustrating a semiconductor light emitting device according to a sixth embodiment.

FIG. 7 is a sectional view showing a semiconductor light emitting device of a seventh embodiment.

FIG. 8 is a sectional view showing a semiconductor light emitting device according to an eighth embodiment.

FIG. 9 is a sectional view showing a semiconductor light emitting device according to a ninth embodiment.

FIG. 10 is a sectional view showing a semiconductor light emitting device according to a tenth embodiment.

FIG. 11 is a sectional view showing a semiconductor light emitting device according to an eleventh embodiment.

FIG. 12 is a sectional view showing a semiconductor light emitting device according to a twelfth embodiment.

FIG. 13 is a sectional view showing a semiconductor light emitting device according to a thirteenth embodiment.

FIG. 14 is a sectional view of a semiconductor light emitting device according to a fourteenth embodiment.

FIG. 15 is a sectional view of a conventional semiconductor light emitting device.

[Explanation of symbols]

1, 21, 31, 41, 51, 61, 71, 81, 9
1, 101, 111, 121, 131, 141 n-type substrate 2, 22, 32, 42, 52, 62, 72, 82, 9
2, 102, 112, 122, 132, 142 n-type cladding layers 3, 23, 33, 43, 53, 63, 73, 83, 9
3, 103, 113, 123, 133, 143 Active layer 4, 24, 34, 44, 54, 64, 74, 84, 9
4, 104, 114, 124, 134, 144 p-type cladding layer 5, 25, 35, 45, 55, 75, 95, 105, 1,
15, 125, 135, 145 Protective layer 6, 26, 36, 46, 56, 66, 68, 76, 8
6, 88, 96, 106, 116, 126, 136, 1
46 current blocking layers 7, 27, 37, 47, 57a, 57b, 67, 77,
87a, 87b, 97, 107a, 107b, 117,
127, 137, 147 Current diffusion layer 119, 139, 149 Contact layer 10, 210, 310, 410, 510, 610, 71
0, 810, 910, 1010, 1110, 1210,
1310, 1410 n-type electrode 11, 211, 311, 411, 511, 611, 71
1, 811, 911, 1011, 1111, 1211,
1311, 1411 p-type electrode

Claims (7)

[Claims] 1. A semiconductor in which a current blocking layer is partially provided on a compound semiconductor laminated structure having a light emitting portion provided on a substrate, and the current blocking layer is not formed on the current blocking layer and the current blocking layer. A current diffusion layer made of a compound semiconductor containing no Al or having an Al composition greater than 0 and 0.3 or less and having a band gap larger than that of the light-emitting portion is provided over the stacked structure portion. A semiconductor light emitting device having a light extraction side electrode provided on a current diffusion layer so as to face the current blocking layer. 2. The semiconductor device according to claim 2, wherein the compound semiconductor laminated structure having a light emitting portion provided on the substrate does not contain Al or has an Al composition of more than 0 and 0.3 or less. A first current spreading layer made of a compound semiconductor having a large band gap is provided, a current blocking layer is provided partially on the first current spreading layer, and the current blocking layer and the current blocking layer are formed. Over the first current diffusion layer that does not include the second conductive type of a compound semiconductor containing no Al or having an Al composition of greater than 0 and less than or equal to 0.3 and a band gap larger than the light emitting portion. A semiconductor light emitting device comprising: a second current diffusion layer; and a light extraction side electrode provided on the second current diffusion layer so as to face the current blocking layer. 3. The compound semiconductor multilayer structure includes at least a first conductivity type compound semiconductor layer and a second conductivity type compound semiconductor layer, wherein the first conductivity type semiconductor layer is a second conductivity type semiconductor layer. 3. The semiconductor light emitting device according to claim 1, wherein the current blocking layer is provided closer to the substrate side, and the current blocking layer is made of a first conductivity type compound semiconductor or a high resistance material. 4. 4. The compound semiconductor multilayer structure includes at least a first conductivity type compound semiconductor layer and a second conductivity type compound semiconductor layer, wherein the first conductivity type semiconductor layer is a second conductivity type semiconductor layer. The current blocking layer is made of a second conductivity type compound semiconductor, and the current blocking layer is formed so that the hetero barrier in the current blocking layer formation region is The semiconductor light-emitting device according to claim 1, wherein the semiconductor light-emitting device is larger than the heterobarrier in the non-forming region. 5. The current diffusion layer is of a second conductivity type and is made of GaP, Zn _a Mg _{1 -a} S _{1 -b} Se _b (0 ≦ a ≦ 1, 0
_{≦ b ≦ 1), Ga 1} -c In c N (0 ≦ c ≦ 1), (Al x
Ga _1-x ) _1-y In _y P (0 <x ≦ 0.3, 0 ≦ y ≦
_{1), (Al s Ga 1} -s) 1-t In t N (0 <s ≦ 0.3,
0 ≦ t ≦ 1) or (Al _p Ga _1-p ) _{1-q Inq} As (0
5. The semiconductor light emitting device according to claim 1, wherein <p ≦ 0.3, 0 ≦ q ≦ 1). 6. _Gn In _1-n P (0 ≦ n ≦ 1), Al _m Ga _1-m between the current blocking layer and the semiconductor multilayer structure.
As (0 ≦ m ≦ 1) , (Zn d Mg 1-d) S 1-e Se e (0
≦ d ≦ 1, 0 ≦ e ≦ 1), Ga _A In _1- AN (0 ≦ A ≦
1) or _{(Al D Ga 1-D)} 1-E In E As (0 ≦ D ≦
The semiconductor light-emitting device according to claim 1, further comprising a protective layer comprising: 1, 0 ≦ E ≦ 1). 7. The light-emitting unit according to claim 1, wherein the light emitting unit is Al _i Ga _{1 -i} As (0 ≦ i
≦ 1) or _{(Al j Ga 1-j)} 1-k In k As (0 ≦ j ≦
7. The method according to claim 1, wherein the following condition is satisfied: 1, 0 ≦ k ≦ 1).
4. A semiconductor light emitting device according to any one of the above.