JPH0974221A - Semiconductor light emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture the high reliable and brightness semiconductor light emitting element by improving the light emitting efficiency while suppressing the decline in element characteristics and reliability due to the oxidation of a current diffused layer. SOLUTION: The semiconductor light emitting element is provided with a current diffused layer 7 between a light emitting part 3a including an active lawyer 3 and a p-type electrode 11 while a current blocking layer 6 opposing to the electrode 11 is provided between the current diffused layer 7 and the light emitting part 3a furthermore, the current diffused layer 7 is composed of a compound semiconductor (GaP) including no Al at all making a larger gap than that of the light emitting part 3a.

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, and more particularly to a semiconductor light emitting device using an AlGaInP based semiconductor material.

[0002]

2. Description of the Related Art AlGaInP-based materials have the largest direct transition type band gap among the III-V group compound semiconductor materials excluding nitrides, and have attracted attention as a light-emitting device material family in the 0.5 to 0.6 μm band. ing. In particular, a pn junction type light emitting diode (LED) using GaAs as a substrate material and having a light emitting portion made of AlGaInP lattice-matched to this.
Is capable of emitting light with high brightness in a wavelength range extending from red to green, as compared with a conventional material using an indirect transition type material such as GaP or GaAsP.

Further, in order to realize a high-brightness LED, it is effective not only to increase the luminous efficiency but also to the outside in consideration of light absorption inside the element, relative positional relationship between the light emitting portion and the electrode, and the like. It is important to realize light extraction.

FIG. 14 is a sectional view showing the structure of a conventional LED having an AlGaInP light emitting portion (see Japanese Patent Laid-Open No. 4-229665).

In the figure, reference numeral 201 denotes a pn junction light emitting diode (LED), and an AlGaInP active layer 213 is provided on an n-GaAs substrate 211 thereof with an n-AlGaInP active layer 213.
A laminated structure 210 sandwiched by a lower clad layer 212 and a p-AlGaInP upper clad layer 214 is provided, and this laminated structure 210 has a double heterojunction portion, and light generated in the active layer 213 is emitted. It is a light emitting part.

A p-GaAs contact layer 219 is formed at the center of the surface of the upper cladding layer 214, and a p-type electrode 201b made of AuZn is provided on the contact layer 219, and n is formed. -GaAs substrate 21
N-type electrode 201a made of AuGe is formed on the entire back surface of
Are formed.

In the LED 201, a portion directly below the p-type electrode 201b of the active layer 213 and a peripheral portion thereof form a light emitting region 240, and an operating current flows into this portion as indicated by an arrow A. There is.

However, the LE having the structure shown in FIG.
In D201, p-AlGaInP upper cladding layer 214
Has a large resistivity, the current does not spread so much in the cladding layer. Therefore, the light emitting region 240 in the active layer 213 is provided in the contact layer 219 and the electrode 201b.
It is only the part directly under. That is, in the LED 201, the emitted light that is going to be emitted to the outside of the element is blocked by the p-type electrode 201b, and the light extraction efficiency in the upper surface direction of the element is extremely low.

In order to solve such a problem, in order to improve the current distribution in the light emitting section 210, an element structure is proposed in which a layer for diffusing the current is provided between the light emitting section and the electrode on the light extraction side. ing.

For example, Japanese Unexamined Patent Publication No. 4-229665 discloses an LED adopting this element structure.
The LED will be described below.

FIG. 15 is a cross-sectional view for explaining the LED. In the figure, 202 is a pn junction light emitting diode (LED), and like the LED 201, its n-Ga.
An AlGaInP active layer 223 is formed on the As substrate 221, and an n-AlGaInP lower cladding layer 222 and a p-AlG are formed.
A laminated structure 210 sandwiched between aInP upper cladding layers 224 is provided, and this laminated structure 220 has a double heterojunction portion and serves as a light emitting portion from which light generated in the active layer 223 is emitted. .

In the LED 202, the surface of the upper clad layer 224 constituting the light emitting portion is p-GaIn.
An intermediate bandgap layer (hereinafter also referred to as a protective film) 225 made of P is covered, and a current blocking layer 22 made of n-AlGaInP is formed in the central portion of the protective film 225.
6 are arranged. A current diffusion layer 227 made of p-AlGaAs is formed on the protective film 225 and the current blocking layer 226. On the surface of the current diffusion layer 227, a current diffusion layer 227 is formed so as to face the current blocking layer 226. -GaA
A contact layer 229 made of s is arranged, and a p-type electrode (AuZn) 202b is provided on the contact layer 229. An n-type electrode 202a made of AuGe is formed on the entire back surface of the n-GaAs substrate 201.

Next, a method of manufacturing the LED 202 will be described.

First, n-A is formed on the n-GaAs substrate 221.
lGaInP lower clad layer 222, AlGaInP active layer 223, p-AlGaInP upper clad layer 224, p
-GaInP intermediate bandgap layer 225, and n-A
The lGaInP current blocking layer 226 is sequentially grown.

Next, the n-AlGaInP current blocking layer 22 is formed.
6 is processed into a circular shape, for example, by selective etching. Next, the intermediate band gap layer 225 and the current blocking layer 2
P-AlGaAs current spreading layer 227 and p-
The GaAs contact layer 229 is sequentially grown.

Then, the p-GaAs contact layer 229
The p-type electrode 202b made of AuZn and n-G
The n-type electrode 2 made of AuGe is provided on the side of the aAs substrate 151.
02a is formed.

Here, the p-type electrode 202b is n-A formed by a lift-off method using a resist or an etching method.
It is patterned so as to remain only directly above the 1GaInP current blocking layer 226, and the p-
The GaAs contact layer 229 has been removed by selective etching.

In this LED 202, the p-type electrode 202b
The current injected from the current diffusion layer 227 into the current diffusion layer 227 is diffused in the layer direction by the current diffusion layer 227, and further, the current blocking layer 22.
6 to the outside of the p-cladding layer 224
Is injected into. Therefore, the light emitting region can be expanded to a wide area of the active layer other than directly under the p-type electrode, and the light extraction efficiency can be improved.

[0019]

However, in the conventional semiconductor light emitting element described above, the current spreading layer is made of GaAs.
From the viewpoint of lattice matching with the substrate, AlGa containing Al
Since As was used, there were the following problems.

The first problem is (Al _x Ga _{1 -x} )
_1-y In y when the Al composition x of P active layer is a yellow light emitting element (emission wavelength 585～590Nm) is 0.3, Al _x G
The band gap of the a _1-x As current diffusion layer is larger than the band gap of the active layer (2.2 eV), and Al _x Ga is required to be transparent to light emitted from the active layer.
The Al composition x of _1-x As had to be set to 0.7 (2.38 eV in band gap) or more.

Further, Al has a high reactivity among the compounds and is easily bonded to oxygen in the atmosphere, so that Al _x Ga _1-x A
Oxidation of Al in the s current diffusion layer was a very big problem. Al _x Ga _1-x As As a result of the oxidation of Al in the current diffusion layer due to the bond with oxygen, the crystallinity of the current diffusion layer is reduced, and light absorption due to the formation of deep levels occurs, which may affect the device characteristics. It had a bad effect.

Further, the light emitting element has many applications such as outdoor display, and particularly when it is operated under high temperature and high humidity conditions such as outdoors, the brightness is lowered due to the presence of Al in the current diffusion layer. In addition, there is a problem that the reliability is significantly reduced.

The second problem is that (Al _x Ga _1-x )
In the case of a green light emitting device (emission wavelength 555 nm) in which the Al composition x of the _1-y In _y P active layer is 0.5, Al _x Ga _1-x As
To prevent the current spreading layer from absorbing light from the active layer, the Al composition x must be further increased.
As the l composition becomes higher, the band gap does not increase so much even with the increase, and the Al composition increases.
It has been difficult to reduce the absorption of emitted light in the current diffusion layer.

A third problem is that in an Al _x Ga _1-x As layer having an Al composition x of 0.7 or more, ionization of p-type dopants such as Zn, Be and Mg is caused by the effect of oxygen combined with Al. Since the ratio is low, it is necessary to supply a large amount of p-type dopant to set a desired carrier concentration. For this reason, many p-type dopants exist in addition to the lattice positions, and these dopants diffuse into the cladding layer and the active layer during growth, resulting in deterioration of device characteristics.

The present invention has been made in order to solve the above-mentioned conventional problems, and improves the current distribution in the light emitting portion, and also improves the light absorption and oxidation in the current diffusion layer to guide the light. An object of the present invention is to provide a high-luminance semiconductor light emitting device with improved efficiency.

[0026]

Means for Solving the Problems Accordingly, the present inventor has proposed:
As a result of diligent research aimed at achieving the above-mentioned object, the current diffusion layer is focused on the point that it is separated from the active layer by a distance corresponding to at least the thickness of the upper cladding layer. A for lattice matching with GaAs)
Apart from the common sense that 1GaAs is used, it has been found that a material that does not lattice match with GaAs can be used as its constituent material.

That is, it has been found that the above problem can be solved by using a compound semiconductor which is larger than the bandgap of the active layer and does not contain Al as the current diffusion layer.

A semiconductor light emitting device according to the present invention (claim 1) is a compound semiconductor substrate of the first conductivity type, and at least a cladding layer of the first conductivity type, an active layer and a second conductivity type on the compound semiconductor substrate. A light emitting part formed by sequentially forming a clad layer, a first conductivity type current blocking layer disposed on a predetermined region of the light emitting part, and formed on the light emitting part and the first conductivity type current blocking layer. And a light-extraction-side electrode disposed on the current diffusion layer so as to face the current blocking layer.

The current blocking layer blocks current flow between the light extraction side electrode and the light emitting portion,
The current diffusion layer diffuses the current so that the cross-sectional area of the current path between the light extraction side electrode and the light emitting portion becomes wider toward the light emitting portion side.

The current diffusion layer is composed of a compound semiconductor that does not contain Al and has a bandgap larger than that of the semiconductor material forming the light emitting portion. Thereby, the above object is achieved.

A semiconductor light emitting device according to the present invention (claim 2) is a compound semiconductor substrate of the first conductivity type, and at least a cladding layer of the first conductivity type, an active layer and a second conductivity type on the compound semiconductor substrate. A light emitting portion formed by sequentially forming a clad layer, a second conductive type first current diffusion layer formed on the light emitting portion, and a predetermined region of the light emitting portion on the first current diffusion layer. A current blocking layer of a first conductivity type disposed so as to face the first current spreading layer, a second current spreading layer of a second conductivity type formed on the first current spreading layer and the current blocking layer, and a second current spreading layer of the second conductivity type. An electrode on the light extraction side formed at a position facing the current blocking layer on the current diffusion layer.

The current blocking layer blocks the flow of current between the light extraction side electrode and the light emitting portion, and the first and second current diffusion layers are respectively connected to the light extraction side electrode and the light extraction side electrode. The current is diffused so that the cross-sectional area of the current path between the light emitting portion and the light emitting portion becomes wider toward the light emitting portion side.

The current diffusion layer is composed of a compound semiconductor that does not contain Al and has a bandgap larger than that of the semiconductor material forming the light emitting portion. Thereby, the above object is achieved.

A semiconductor light emitting device according to the present invention (claim 3) is a compound semiconductor substrate of the first conductivity type, and at least a cladding layer of the first conductivity type, an active layer and a second conductivity type on the compound semiconductor substrate. Light emitting portion formed by sequentially forming a clad layer, a second conductivity type current blocking layer disposed on a predetermined region of the light emitting portion, and a second conductive material formed on the light emitting portion and the current spreading layer. A current diffusion layer of a mold and an electrode on the light extraction side arranged on the current diffusion layer so as to face the current blocking layer.

The current blocking layer blocks current flow between the light extraction side electrode and the light emitting portion,
A hetero barrier larger than a hetero barrier between the light emitting portion and the current diffusion layer is formed between the current blocking layer and the light emitting portion.

The current diffusion layer diffuses the current so that the cross-sectional area of the current path between the light extraction side electrode and the light emitting portion becomes wider toward the light emitting portion side, and constitutes the light emitting portion. Has a larger bandgap than semiconductor materials
It is composed of a compound semiconductor not containing l. Thereby, the above object is achieved.

A semiconductor light emitting device according to the present invention (claim 4) is a compound semiconductor substrate of the first conductivity type, and at least a cladding layer of the first conductivity type, an active layer and a second conductivity type on the compound semiconductor substrate. A clad layer is sequentially formed, a second conductive type first current spreading layer formed on the light emitting part, and a predetermined light emitting part of the light emitting part on the first current spreading layer. A second conductivity type current blocking layer disposed so as to face the region, a second conductivity type second current spreading layer formed on the first current spreading layer and the current blocking layer, and the second And a light extraction side electrode formed on the current diffusion layer so as to face the current blocking layer.

The current blocking layer blocks current flow between the light extraction side electrode and the light emitting portion,
A hetero barrier larger than a hetero barrier between the light emitting portion and the current diffusion layer is formed between the current blocking layer and the light emitting portion.

The first and second current diffusion layers diffuse the current such that the cross-sectional area of the current path between the light extraction side electrode and the light emitting portion becomes wider toward the light emitting portion side. The both current diffusion layers are composed of a compound semiconductor that does not contain Al and has a band gap larger than that of the semiconductor material forming the light emitting portion. Thereby, the above object is achieved.

A semiconductor light emitting device according to the present invention (claim 5) is a compound semiconductor substrate of the first conductivity type, and at least a cladding layer of the first conductivity type, an active layer and a second conductivity type on the compound semiconductor substrate. And a current blocking layer disposed on a predetermined region of the light emitting section, and a second conductivity type current spreading layer formed on the light emitting section and the current blocking layer. A light extraction side electrode arranged on the current diffusion layer so as to face the current blocking layer.

The current blocking layer has a higher resistance than the compound semiconductor forming the current diffusion layer so as to block the flow of current between the light extraction side electrode and the light emitting portion.

The current diffusion layer diffuses the current so that the cross-sectional area of the current path between the light extraction side electrode and the light emitting portion becomes wider toward the light emitting portion side, and constitutes the light emitting portion. Has a larger bandgap than semiconductor materials
It is composed of a compound semiconductor not containing l. Thereby, the above object is achieved.

A semiconductor light emitting device according to the present invention (claim 6) is a compound semiconductor substrate of a first conductivity type, and at least a clad layer of the first conductivity type, an active layer and a second conductivity type on the compound semiconductor substrate. A clad layer is sequentially formed, a second conductive type first current spreading layer formed on the light emitting part, and a predetermined light emitting part of the light emitting part on the first current spreading layer. A current blocking layer disposed so as to face the region, a second current spreading layer of the second conductivity type formed on the first current spreading layer and the current blocking layer, and on the second current spreading layer And an electrode on the light extraction side formed so as to face the current blocking layer.

The current blocking layer has a higher resistance than the compound semiconductor forming the current diffusion layer so as to block the flow of current between the light extraction side electrode and the light emitting portion.

Each of the first and second current diffusion layers diffuses the current so that the cross-sectional area of the current path between the light extraction side electrode and the light emitting portion becomes wider toward the light emitting portion side. Both of the current diffusion layers are made of a compound semiconductor that does not contain Al and has a bandgap larger than that of the semiconductor material forming the light emitting portion. Thereby, the above object is achieved.

Here, in the semiconductor light emitting device according to any one of claims 1 to 6, the active layer is (Al _x Ga _1-x ) _1-y In _y
It is preferably composed of a P layer (0 ≦ x ≦ 1, 0 ≦ y ≦ 1).

The present invention (Claim 7) includes Claims 1 to 6.
In the semiconductor light emitting device according to any one of 1 to 3, the current diffusion layer is composed of a GaP layer.

The present invention (Claim 8) includes Claims 1 to 6.
In the semiconductor light-emitting device according to any one of items 1 to 5, the current diffusion layer is formed of (Zn _x Mg _1-x ) S _1-y Se _y (0 ≦ x ≦ 1,0
≦ y ≦ 1) layer or ZnTe layer.

According to a ninth aspect of the present invention, in the semiconductor light emitting device according to any one of the first to sixth aspects, the current diffusion layer is composed of a Ga _{1 -y} In _y N (0≤y≤1) layer. It was done.

According to a tenth aspect of the present invention, in the semiconductor light emitting device according to any one of the first to sixth aspects, the surface of the second conductivity type cladding layer on the upper side of the active layer forming the light emitting portion is protected by a protective film. The protective film is covered with a semiconductor material having etching selectivity with respect to the semiconductor material forming the current blocking layer.

According to a tenth aspect of the present invention, in the semiconductor light emitting device according to the tenth aspect, the current blocking layer is made of Al.
_x Ga _1-x As (0 ≦ x ≦ 1) layer or (Al _x G
a _1-x ) _{1- y} In _y P (0 <x ≦ 1, 0 <y ≦ 1) layer, and the protective film is Ga _1-y In _y P (0 ≦ y ≦ 1)
It is composed of layers.

According to the present invention (claim 12), in the semiconductor light emitting device according to any one of claims 1 to 6, the current diffusion layer is made of an Al composition having a band gap larger than that of a semiconductor material forming the light emitting portion. It is composed of a compound semiconductor of 0.3 or less.

According to a thirteenth aspect of the present invention, in the semiconductor light emitting element according to the twelfth aspect, the current diffusion layer is formed of (Al
_x Ga _1-x ) _1-y In _y P (0 <x ≦ 0.3, 0 ≦ y ≦ 1)
It is composed of layers.

The present invention (claim 14) provides the semiconductor light-emitting device according to claim 12, wherein the current diffusion layer is made of (Al
_x Ga _1-x ) _1-y In _y N (0 <x ≦ 0.3, 0 ≦ y ≦ 1)
It is composed of layers.

The operation of the present invention will be described below.

According to the present invention (claim 1), a current diffusion layer is provided between the light extraction side electrode and the light emitting portion to diffuse the current so that the cross-sectional area of the current path becomes wider toward the light emitting portion side. Therefore, it is possible to realize light emission in a wide area of the active layer other than directly under the electrode, improve the light extraction efficiency, and increase the brightness of the semiconductor light emitting device.

Further, since the current diffusion layer is made of a compound semiconductor having a bandgap larger than that of the light emitting portion, light from the active layer is not absorbed by the current diffusion layer, and the light extraction efficiency is further improved. Therefore, it is possible to further increase the brightness of the semiconductor light emitting device. Further, the current spreading layer is A
Since the current diffusion layer does not include l,
Element characteristics and reliability can be improved as compared with the conventional light emitting element made of AlGaAs lattice-matched with the aAs substrate.

That is, AlGaA is used for the conventional current spreading layer.
In LED with s layer, Al is greater reactivity among the compounds, easily attached such as oxygen in the air, Al _x G
Oxidation of Al in the a _1-x As current diffusion layer deteriorates the crystallinity of the current diffusion layer and adversely affects the device characteristics such as absorption of light due to the formation of deep levels. In addition, the light-emitting element has many applications such as outdoor display, and when it is operated under such a high temperature and high humidity condition, the brightness and reliability are significantly reduced.

On the other hand, in the present invention, the current spreading layer has A
Since 1 is not contained, there is no reaction between the constituent elements of the current diffusion layer and oxygen, and problems such as deterioration of device characteristics and reliability due to oxygen can be greatly improved.

Further, since the current diffusion layer is separated from the active layer by a distance corresponding to at least the layer thickness of the upper cladding layer, even if the compound semiconductor forming the current diffusion layer is not lattice-matched with the substrate material, It has almost no effect on the active layer. Further, by forming the active layer thin, it is possible to reduce the influence of lattice mismatch between the constituent material of the current spreading layer and the substrate material on the active layer.

According to the present invention (Claim 2), Claim 1
In addition to the above configuration, the second conductivity type current spreading layer is made into two layers,
Since the current blocking layer of the first conductivity type is provided between them, the current spreading to the peripheral portion of the current blocking layer directly below the electrode in the current spreading layer on the electrode side further spreads to the current spreading layer on the light emitting section side. Therefore, the light emitting region in the active layer can be further expanded.

In the present invention (claim 3), unlike the claim 1, the current blocking layer is formed of a semiconductor layer of the same conductivity type as the current diffusion layer, and the current is spread by utilizing the difference in the hetero barrier. Therefore, all the semiconductor layers on the light emitting portion can be formed by crystal growth of semiconductor layers of the same conductivity type, which simplifies the manufacturing process and prevents adverse effects due to re-diffusion of impurities of the opposite conductivity type. It becomes possible.

According to the present invention (claim 4), in addition to the structure of claim 3, the current diffusion layer is composed of two layers, and the current blocking layer utilizing the hetero barrier is provided between them. The current spreading in the current spreading layer to the peripheral portion of the current blocking layer directly below the electrode is further spread in the current spreading layer on the light emitting portion side, and the light emitting region in the active layer can be further expanded.

In the present invention (Claim 5), by spreading the current over a wider area by the high resistance current blocking layer, it is possible to realize light emission over a wide area other than the portion of the active layer facing the electrode. A high-brightness semiconductor light emitting device with improved derivation efficiency can be obtained. Further, since it is not necessary to control the conductivity type and 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.

In the present invention (claim 6), in addition to the structure of claim 5, two second conductivity type current diffusion layers are provided, and a high resistance current blocking layer is provided between them. The current spreading to the peripheral portion of the current blocking layer directly below the electrode in the current diffusion layer on the electrode side is further spread to the current diffusion layer on the light emitting portion side, and the light emitting region in the active layer can be further expanded.

In the present invention (claim 7), the current diffusion layer is composed of a GaP layer. The GaP layer is the conventional A
Unlike 1GaAs, it does not contain Al. Therefore, there is no oxidation due to the bond between the constituent elements of the current diffusion layer and oxygen, the deterioration of the device characteristics such as the deterioration of crystallinity and the absorption of light due to the formation of deep levels, and the deterioration of the brightness under high temperature and high humidity conditions. Is greatly improved, and the reliability can be greatly improved.

The GaP layer is made of AlGa used in the conventional example.
Since the bandgap is larger than that of As, and the absorption of the light emitted from the light emitting portion can be reduced, the light emitting efficiency can be further improved and a semiconductor light emitting element with high brightness can be obtained. In addition, the GaP layer can be in ohmic contact with a metal material, and the electrode can be directly provided on the surface of the GaP layer, so that the contact layer set in the conventional example is not necessary and the number of steps can be reduced.
Significant cost reduction can be realized.

In the present invention (claim 8), the current spreading layer is formed of (Zn _x Mg _1-x ) S _1-y Se _y (0 ≦ x ≦ 1,0 ≦
Since it is composed of a y ≦ 1) layer or a ZnTe layer, the same (Zn _x Mg _1-x ) S _ly Se _y as the GaP layer of claim 7 is formed.
The layer does not contain Al, unlike the AlGaAs current spreading layer of conventional LEDs. Therefore, there is no oxidation due to the combination of the constituent elements of the current diffusion layer with oxygen, and the deterioration of the device characteristics such as the deterioration of crystallinity and the absorption of light due to the formation of deep levels and the deterioration of the brightness under high temperature and high humidity conditions. Is greatly improved, and the reliability can be greatly improved.

Further, since the band gap of the (Zn _x Mg _1-x ) S _ly Se _y layer or ZnTe layer can be made larger than that of the GaP layer, absorption of light emitted from the light emitting portion can be further reduced. Further, a high-brightness semiconductor light emitting device can be obtained by further improving the light extraction efficiency. In addition, (Zn _x
Since Mg _1-x ) S _1-y Se _y (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) or ZnTe layer can be lattice-matched with the GaAs substrate and the light-emitting portion, it is caused by the lattice mismatch with the light-emitting portion. Has no adverse effect.

The ZnMgSSe layer or Zn
The growth temperature of the Te layer is as low as 600 ° C., and re-diffusion in the light emitting portion can be suppressed during the process of forming the current diffusion layer.

In the present invention (claim 9), since the current diffusion layer is composed of the Ga _1-y In _y N (0 ≦ y ≦ 1) layer, the Ga _1-y In _y N (0 ≦ y) Since the ≦ 1) layer can have a larger bandgap than the GaP layer, it is possible to further reduce the absorption of light emitted from the light emitting portion, improve the light extraction efficiency, and obtain a semiconductor light emitting device with high brightness. To be However, the Ga _1-y In _y N layer does not lattice match with GaAs used as a substrate material, and its growth temperature is 10
00 ° C and the growth temperature of the ZnMgSSe layer (600 ° C
Higher than C).

In the present invention (claim 10), a protective film is provided between the current blocking layer and the light emitting portion, and the protective film is made of a semiconductor material having etching selectivity with respect to the semiconductor material forming the current blocking layer. (Al _x Ga _1-x ) _1-y before re-growth, that is, before growth of the current diffusion layer
While preventing oxidation due to exposure of the In _y P clad layer,
Selective etching becomes possible at the time of etching the current blocking layer, and the manufacturing process can be greatly simplified.

In the present invention (claim 11), the current blocking layer is an Al _x Ga _1-x As (0 ≦ x ≦ 1) layer or an (Al _x Ga _1-x ) _1-y In _y P ( 0 <x ≦ 1, 0 <y
≦ 1) layer, and the protective film is formed of Ga _1-y In _y P
Since it is composed of (0 ≦ y ≦ 1) layers, as an etchant for etching the current blocking layer, a phosphoric acid-based solution such as H ₂ PO ₃ or a mixed solution of sulfuric acid and hydrogen peroxide solution (sulfuric acid) is used. : H ₂ O ₂ : H ₂ O set to a predetermined ratio) or aqua regia (mixed solution of hydrochloric acid and nitric acid), etc., the difference in etching rate between the protective film and the current blocking layer Occurs, and selective etching of the current blocking layer can be easily performed.

In the present invention (claim 12), since the current diffusion layer is made of a compound semiconductor having a bandgap larger than that of the light emitting portion and an Al composition of 0.3 or less, the current diffusion layer is relatively oxidized. Less likely to occur and less likely to reduce reliability.

In the present invention (claim 13), the current diffusion layer is composed of an AlGaInP layer having a bandgap larger than that of the light emitting portion and an Al composition of 0.3 or less.
Similar to the above, the current diffusion layer is less likely to be oxidized, and a decrease in reliability can be prevented.

The AlGaInP layer has an Al composition of 0.
Even if it is 3 or less, it is possible to set the bandgap larger than that of AlGaAs used in the conventional example, and it is possible to reduce the absorption of the light emitted from the light emitting portion. A semiconductor light emitting device can be obtained. In addition, since the AlGaInP layer can be lattice-matched with the GaAs substrate and the light emitting portion, there is no adverse effect due to the lattice mismatch with the light emitting portion.

In the present invention (claim 14), the current diffusion layer is composed of an AlGaInN layer having a band gap larger than that of the light emitting portion and an Al composition of 0.3 or less. Even if the Al composition of the element is 0.3 or less, it is possible to make the bandgap larger than that of GaP, and it is less likely to be adversely affected by the oxidation of the current diffusion layer and further reduce the absorption of light emitted from the light emitting portion. Therefore, it is possible to obtain a semiconductor light emitting device with higher brightness by further improving the light extraction efficiency.

[0078]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 is a diagram for explaining a semiconductor light emitting device according to Embodiment 1 of the present invention.
FIG. 1D is a diagram showing a manufacturing process of the semiconductor light emitting device in the order of steps.

In the figure, reference numeral 1001 denotes a light emitting diode which is the semiconductor light emitting element of the first embodiment. On the n type GaAs substrate 1 which constitutes the light emitting diode 1001, the n type lower cladding layer 2 is formed on the surface thereof. A light emitting portion 3a, which is formed by sequentially crystallizing the active layer 3 and the p-type upper cladding layer 4, is arranged. The light emitting portion 3a has a double heterojunction portion, and the light generated in the active layer 3 is emitted. It is supposed to do.

The surface of the p-type upper cladding layer 4 of the light emitting portion 3a is covered with the p-type protective layer 5, and the n-type GaP current blocking layer 6 is arranged on a predetermined region of the surface of the protective layer 5. Has been done. Moreover, p is formed on the protective layer 5 and the current blocking layer 6.
A type GaP current diffusion layer 7 is formed, and Au is formed on the surface of the current diffusion layer 7 so as to face the current blocking layer 6.
A p-type electrode 11 made of Zn is arranged. Strictly speaking, the p-type electrode has a two-layer structure of a lower AuZn layer and an upper Au layer.

Here, the lower clad layer 2, the active layer 3,
And the upper clad layer 4 are (Al _x Ga _1-x ) _{1-y, respectively.}
In _y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1). In the lower clad layer 2 and the upper clad layer 4, for example, the composition ratios x and y are x = 1.0 and y = 0.50, and the layer thicknesses thereof are both 1.0 μm. The carrier concentration of the dopant Si and the carrier concentration of the dopant Zn in the upper cladding layer 4 are both 5 × 10 ¹⁷ cm ⁻³ . Further, in the active layer 3, the composition ratio x, y
Is x = 0.30, y = 0.50, the layer thickness is 0.50μ
It has become m.

Further, the protective layer 5 has, for example, a composition ratio y.
= 0 p-type Ga _1-y In _y P (0 ≦ y ≦ 1), the layer thickness is 0.1 μm, and the carrier concentration of the dopant Zn is 5 × 10 ¹⁸ cm ⁻³ . Also, the n-type G
The aP current blocking layer 6 has a layer thickness of 0.3 μm and a dopant Si carrier concentration of 2 × 10 ¹⁸ cm ⁻³ . The p-type GaP current diffusion layer 7 has a layer thickness of 5 μm and a dopant Zn carrier concentration of 5 × 1.
It is 0 ¹⁸ cm ^-3 . An n-type electrode 10 made of AuGe is formed on the back surface of the n-type GaAs substrate 21.

Next, the manufacturing method will be described.

First, an n-type A is formed on the n-type GaAs substrate 1.
The thickness of 1.0 μm so that the Si carrier concentration is 5 × 10 ¹⁷ cm ^{−3 by using} 1 _0.5 In _0.5 P as the n-type lower cladding layer 2.
Grow to a degree. Then, (Al _0.3 Ga _0.7 ) _0.5 In
_0.5 P is formed as an active layer 3 to a thickness of about 0.50 μm, and p-type Al _0.5 In _0.5 P is further formed as a p-type upper cladding layer 4 on which Zn carrier concentration is 5 × 10 ¹⁷ cm ^−3.
To a thickness of about 1 μm.

Subsequently, p-type Ga is formed on the upper cladding layer 4.
With P as the protective layer 5, the Zn carrier concentration is 5 × 10 ¹⁸ c
was grown to a thickness 0.1μm about so as to be m ^-3, further as the current blocking layer 6 n-type GaP thereon, the thickness of 0.3μm to Si carrier concentration of 2 × 10 ¹⁸ cm ^-3 Sequentially grows (FIG. 1 (a)).

Next, a resist film 12 having a predetermined pattern is formed on the n-type GaP current blocking layer 6, and the n-type GaP is formed.
The current blocking layer 6 is selectively etched so that it has a circular plane pattern (FIG. 1 (b)).

After this etching, the resist film 12 is removed (FIG. 1C), and the p-type GaP is used as the current diffusion layer 7.
5 μm so that the Zn carrier concentration is 5 × 10 ¹⁸ cm ⁻³
It grows to a certain thickness. After that, the p-type electrode 11 made of AuZn is formed on the current diffusion layer 7 and AuG is formed on the back surface of the substrate.
An n-type electrode 10 made of e is formed.

Next, as shown in FIG. 1D, the p-type electrode 1
1 is processed into a circular shape similar to the plane pattern of the current blocking layer 6 so as to face the current blocking layer 6 to complete the light emitting diode 1001.

Although the growth of each semiconductor layer is performed by MOCVD here, the semiconductor growth method is MB
Any growth method such as E method or MOMBE method may be used.

In the first embodiment, the current spreading layer 7 has A
Since the GaP layer not containing 1 was used, there were the following four improvement effects over the conventional example.

As the first effect, since the GaP current diffusion layer 7 does not contain Al, the crystallinity due to the oxidation of Al does not decrease and the reliability of the device is greatly improved.

As the second effect, (Al _x Ga _1-x ) _1-y
Even in the case of a green light emitting device (emission wavelength of 555 nm) in which the Al composition x of the In _y P active layer is 0.5, the GaP layer has a larger bandgap than the active layer and little absorption of light emitted from the active layer. A high-brightness semiconductor light emitting device was obtained by increasing the light extraction efficiency.

As a third effect, the GaP layer has a Zn, B content higher than that of an Al _x Ga _{1 -x} As layer having an Al composition x of 0.7 or more.
Since the ionization rate of p-type dopants such as e and Mg is large, the p-type dopants existing at positions other than the lattice position are reduced,
The diffusion of these dopants during growth can be reduced, and the device characteristics are greatly improved.

As a fourth effect, since the GaP layer can be directly provided with an electrode, the contact layer which is required in the LED using the conventional AlGaAs current diffusion layer is not required, and the contact layer growth step and the etching step are eliminated. Thus, the electrode forming process can be simplified and a significant cost reduction can be realized.

When a voltage was applied in the forward direction to the semiconductor light emitting device according to the first embodiment to pass a current, a peak wavelength of 5
Emission with an intensity of more than 5 cd at 85 nm was obtained. By the way, the conventional LED has a luminous intensity of 1 cd under the same conditions.
Was over.

The composition of the active layer is (Al _x Ga _{1 -x} )
_{When 1-y} In _y P (x = 0.50, y = 0.50) was used, pure green light emission exceeding 3 cd was obtained at the peak wavelength of 555 nm due to the light absorption reduction effect of the GaP layer. By the way, with the conventional LED, the luminous intensity is 1c under the same conditions.
It was about d.

(Second Embodiment) FIG. 2 is a diagram showing a sectional structure of a light emitting diode (semiconductor light emitting element) according to a second embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same elements as the light emitting diode 1001 of the first embodiment, and 1002 is the light emitting diode of the second embodiment. The light emitting diode 1001 of the first embodiment is a current element. The only difference is that an AlGaInP layer is used as the layer 26, and the other configurations are the same as those in the first embodiment.

The current blocking layer 26 is made of n-type (Al _x
Ga _1-x ) _1-y In _y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1), where the composition ratios x and y are x =
0.70, y = 0.50, the carrier concentration of the dopant Si is 2 × 10 ¹⁸ cm ⁻³ , and the layer thickness is 0.3 μm.

In the light emitting diode 1002 of the second embodiment having such a configuration, the current blocking layer 26 is formed of (Al _x G
Since the a _1-x ) _1-y In _y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) layer is used, the following effects are obtained in addition to the effects of the first embodiment.

That is, A which constitutes the current blocking layer 26
With lGaInP and p-type GaP forming the protective layer 25, a phosphoric acid-based solution such as H ₂ PO ₃ or a mixed solution of sulfuric acid and hydrogen peroxide (sulfuric acid: H ₂ O ₂ : H) is used as an etchant.
₂ O set to a predetermined ratio), aqua regia (mixed solution of hydrochloric acid and nitric acid), etc. causes a slight difference in etching rate, which enables selective etching and simplifies the manufacturing process. There is an effect. Note that phosphoric acid as the above-mentioned etchant is AlGaInP at low temperature.
The etching rate of GaP is higher than that of GaP, and at high temperatures, the etching rate of GaP is AlGaIn.
It has the characteristic of being faster than the etching rate of P.

(Embodiment 3) FIG. 3 is a diagram showing a cross-sectional structure of a light emitting diode (semiconductor light emitting element) according to Embodiment 3 of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same parts as the light emitting diode 1001 of the first embodiment.

Reference numeral 1003 denotes the light emitting diode of the third embodiment. In this diode 1003, an AlGaAs layer is used as the current blocking layer 36, and the light emitting portion 33a is used.
As the active layer 33 has a thickness of 0.5 μm (Al _0.5 G
a _0.5 ) _0.5 In _0.5 P layer. The other structure is the same as that of the first embodiment.

That is, the current blocking layer 36 is made of n-type Al.
_{x Ga 1-x As (0} ≦ x ≦ 1) are composed of, in this case, the composition ratio x is x = 0.70, the dopant S
The carrier concentration of i is 2 × 10 ¹⁸ cm ⁻³ , and the layer thickness thereof is 0.1.
It is 3 μm.

In the light emitting diode 1003 of the third embodiment having such a structure, the current blocking layer 36 is formed of Al _x Ga _{1 -x} A.
Since the s (0 ≦ x ≦ 1) layer is used, the following effects are obtained in addition to the effects of the first embodiment.

That is, A which constitutes the current blocking layer 36
lGaAs and p-type GaP forming the protective layer 35 are used as etchants such as a phosphoric acid-based solution such as H ₂ PO ₃ and a mixed solution of sulfuric acid and hydrogen peroxide (sulfuric acid: H ₂ O ₂ : H).
_The difference in the etching rate is caused by using ₂ O set to a predetermined ratio). This is Embodiment 2
Is larger than the difference in etching rate between AlGaInP and GaP, reliable selective etching is possible, and the manufacturing process can be further simplified and the cost can be reduced.

(Embodiment 4) FIG. 4 is a diagram showing a sectional structure of a light emitting diode (semiconductor light emitting element) according to Embodiment 4 of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same elements as those of the light emitting diode of the first embodiment.

Reference numeral 1004 denotes a light emitting diode according to the fourth embodiment. In this light emitting diode 1004, a p-type GaInP layer is used as the protective layer 45 and an n-type AlGaInP layer is used as the current blocking layer 46. Other configurations are the same as those of the light emitting diode 1001 of the first embodiment.

That is, the protective layer 45 is formed of p-type Ga _1-y In _y
P (0 ≦ y ≦ 1), the composition ratio y is y = 0.50, the carrier concentration of the dopant Zn is 5 × 10 ¹⁸ cm ⁻³ , and the layer thickness is 0.1 μm. Has become.

The current blocking layer 46 is made of (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P having a thickness of 0.3 μm, and the carrier concentration of the dopant Si thereof is 2 × 10 ¹⁸ cm ⁻³ . The light emitting diode 1 of the fourth embodiment having such a configuration
In 004, p-type Ga _1-y In _y P (0 ≦ y
Since the ≦ 1) layer is used, the following effects are obtained in addition to the effects of the first embodiment.

The GaInP layer forming the protective layer 45 and the current blocking layer used in the first to third embodiments (Al _x G
a _1-x ) _1-y In _y P layer and Al _x Ga _1-x As,
When the etchants described in the second and third embodiments are used, the etching rates are different. The difference in etching rate in this case is larger than in the second and third embodiments, and reliable selective etching of the current blocking layer with respect to the protective layer is possible, which further simplifies the manufacturing process and reduces cost.

In the fourth embodiment, unlike the first to third embodiments in which GaP is used as the protective film, the GaInP layer of the present embodiment is an absorption layer for the light emission of the active layer 43 due to its composition. However, if the thickness is made sufficiently thin, the absorption effect will be small. Therefore, in the fourth embodiment, the thickness is set to about 100 angstroms.

(Fifth Embodiment) FIG. 5 is a diagram showing a sectional structure of a light emitting diode (semiconductor light emitting element) according to a fifth embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same parts as the light emitting diode 1001 of the first embodiment.

Reference numeral 1005 denotes the light emitting diode of the fifth embodiment. In the light emitting diode 1005, the current diffusion layer has a two-layer structure, and the current blocking layer is provided between them. Further, a p-type GaInP layer is used as the protective film 55, and an n-type AlGaInP layer is used as the current blocking layer 56. The other structure is the same as that of the first embodiment.

That is, the first p-type GaP current diffusion layer 57 is formed on the light emitting portion 3a, and the surface thereof is
The p-type protective layer 55 covers the p-type protective layer 55, and an n-type AlGaInP current blocking layer 56 is formed on a predetermined region of the surface of the p-type protective layer 55.
Is arranged. A second p-type GaP current spreading layer 58 is formed on the protective layer 55 and the current blocking layer 56, and the surface of the current spreading layer 58 faces the current blocking layer 56. P-type electrode 11 made of AuZn
Is arranged.

Here, the first and second current diffusion layers 5 are
The layer thicknesses of 7,58 are 2.5 μm, respectively, and the carrier concentration of the dopant Zn is 5 × 10 ¹⁸ cm ⁻³ . The protective layer 55 is made of p-type Ga _0.5 In _0.5 P, has a layer thickness of 0.1 μm, and has a carrier concentration of the dopant Zn of 5 × 10 ¹⁸ cm ⁻³ . Further, the current blocking layer 56 is formed of n-type (Al _x Ga _1-x ) _1-y In _y P (0
≦ x ≦ 1, 0 ≦ y ≦ 1), where the composition ratio x is x = 0.70, y = 0.50, and the carrier concentration of the dopant Si is 2 × 10 ¹⁸ cm ^{−. 3} , the layer thickness is 0.3 μm.

When a voltage was applied in the forward direction to the semiconductor light emitting device according to the fifth embodiment to pass a current, a peak wavelength of 5 was obtained.
Emission with an intensity of more than 6 cd at 85 nm was obtained.

The composition of the active layer is (Al _x Ga _1-x )
_{When it was set to 1-y} In _y P (x = 0.50, y = 0.50), pure green light emission exceeding 4 cd was obtained at a peak wavelength of 555 nm.

In the light emitting diode according to the fifth embodiment having such a structure, the current diffusion layer has a two-layer structure and the current blocking layer is provided between them. Therefore, in addition to the effect of the first embodiment, the second embodiment is provided. The current spreading in the current spreading layer to the peripheral portion of the current blocking layer directly below the electrode is further spread in the first current spreading layer, which has the effect of further expanding the light emitting region.

(Embodiment 6) FIG. 6 is a diagram showing a sectional structure of a light emitting diode (semiconductor light emitting element) according to Embodiment 6 of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same elements as the light emitting diode 1001 of the first embodiment, and 1006 is the light emitting diode of the sixth embodiment, in which the current blocking layer 66 and the upper cladding layer are included. 4 and the size of the heterobarrier formed between the current diffusion layer 7 and the upper cladding layer 4, the current blocking layer 66.
Has a structure that blocks current. Further, here, a protective layer for covering the surface of the upper clad layer 4 is not provided. The other structure is the same as that of the first embodiment.

That is, the p-type GaAs current blocking layer 66 is formed on a predetermined region of the surface of the p-type upper cladding layer 4 of the light emitting section 3a.
And a p-type AlGaInP current blocking layer 68 is disposed. A p-type GaP current spreading layer 7 is formed on the upper cladding layer 4 and the current blocking layer 68, and the surface of the current spreading layer 7 faces the current blocking layers 66 and 68. A p-type electrode 11 made of AuZn is arranged.

Here, the p-type GaAs current blocking layer 6 is used.
6 has a dopant Zn carrier concentration of 1 × 10 ¹⁷ cm
^-3 , and the layer thickness is 0.3 μm. The p-type AlGaInP current blocking layer 68 is (Al _x Ga _{1 -x} )
_1-y In _y P layer having a composition ratio x, y of x = 0.
7, y = 0.5, the carrier concentration of the dopant Zn is 1 × 10 ¹⁷ cm ⁻³ , and the layer thickness thereof is 0.3 μm.

In the semiconductor light emitting device of the sixth embodiment having such a structure, the valence band is formed at the interface between the p-type GaAs layer forming the current blocking layer 66 and the AlGaInP layer forming the upper cladding layer 4. A large band discontinuity (hetero barrier) is generated on the side, and this hetero discontinuity is caused by the heterogeneity between the AlGaInP layer in the region of the upper clad layer 4 where there is no current blocking layer and the GaP layer forming the current diffusion layer. Greater than discontinuous.

In the present light emitting diode, by utilizing such a band discontinuity structure, the electric current used for light emission can be spread over a wider area of the generation layer, whereby light emission over a wide area can be realized and the light is led out. A high-luminance semiconductor light emitting device with improved efficiency can be obtained.

In the sixth embodiment, the GaAs current blocking layer 66 and the AlGaInP current blocking layer 68 are both p-type.
Since the semiconductor layers on the light emitting portion can all be formed by growing semiconductor crystals of the same conductivity type, the manufacturing process can be simplified and diffusion of impurities of the opposite conductivity type into the p-type upper cladding layer 4 can be performed. It is possible to prevent the influence on the element characteristics due to.

Further, in the present embodiment, the current blocking layer utilizing the hetero barrier has a two-layer structure in which the AlGaInP current blocking layer 68 is further formed on the p-type GaAs current blocking layer 66, so that the current blocking layer is arranged. The current blocking effect in the portion becomes larger than that in the current blocking layer having the single-layer structure.

(Embodiment 7) FIG. 7 is a diagram showing a sectional structure of a light emitting diode (semiconductor light emitting element) according to Embodiment 7 of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same parts as the light emitting diode 1001 of the first embodiment.

Reference numeral 1007 denotes a light emitting diode according to the seventh embodiment. In this light emitting diode 1007, an AlGaP protective layer 75 is formed on the upper clad layer 4 constituting the light emitting portion 3a and corresponds to the electrode 11 on the surface of the protective layer. In the area where
An aAs current blocking layer 76 is provided, and a hetero barrier larger than the hetero barrier between the protective layer 75 and the current diffusion layer 7 is formed between the protective layer 75 and the current blocking layer 76.
Other configurations are the same as those in the first embodiment.

That is, the protective layer 75 is made of p-type Al _x G
a _1-x P (0 ≦ x ≦ 1), the composition ratio x is 0.5,
The layer thickness is 0.1 μm, and the carrier concentration of the dopant Zn is 5 × 10 ¹⁸ cm ⁻³ . The current blocking layer 76 is made of p-type Al _x Ga _1-x As (0 ≦ x ≦ 1), the composition ratio x is 0.7, and the carrier concentration of the dopant Zn is 1 × 10 ¹⁷ cm ^−3. The layer thickness is 0.3 μm.

As described above, in the seventh embodiment, the light emitting section 3
In a region where the current blocking layer 76 on a exists, Al _x Ga _1-x As forming the current blocking layer 76 and Al _x Ga _1-x P forming the protective layer 75 are provided between them. When the junction is formed, a large band discontinuity (heterobarrier) occurs on the valence band side. Due to the composition, this hetero discontinuity is caused in a region where there is no current blocking layer on the light emitting portion 3a.
It can be larger than the hetero discontinuity between Al _x Ga _1-x P layer constituting the protective film 75 and the GaP layer forming the current spreading layer 7. In this light emitting diode, the current supplied to the active layer can be spread over a wide range by utilizing the difference in the size of band discontinuity at the heterojunction surface, and light emission over a wide area can be realized. A high-brightness semiconductor light emitting device with improved light extraction efficiency can be obtained.

Further, in the seventh embodiment, the current blocking layer 7 is used.
Since 6 can be set to be p-type, semiconductor layers of the same conductivity type are all required to be crystal-grown on the light emitting portion, which simplifies the manufacturing process and prevents impurities of the opposite conductivity type from being added to the p-type upper cladding layer. It is possible to prevent the adverse effect of diffusion.

(Embodiment 8) FIG. 8 is a diagram showing a sectional structure of a light emitting diode (semiconductor light emitting element) according to an embodiment 8 of the invention. In the figure, the same reference numerals as those in FIG. 6 denote the same parts as the light emitting diode 1006 of the sixth embodiment.

Reference numeral 1008 denotes the light emitting diode of the eighth embodiment. In the light emitting diode 1008, the current diffusion layer has a two-layer structure, and the current blocking layer is provided between them. Other configurations are the same as those of the light emitting diode 1006 of the sixth embodiment.

That is, the first GaP current diffusion layer 87a is formed on the p-type upper clad layer 4 constituting the light emitting portion 3a, and the p-type current diffusion layer 87a is formed on the predetermined region on the surface of the current diffusion layer 87a. GaAs current blocking layer 66 and p-type (Al _0.7 G
a _0.3 ) _0.5 In _0.5 P current blocking layer 68 is disposed. In addition, the first current spreading layer 87a and the p-type Al
A second p-type GaP current diffusion layer 87b is formed on the GaInP current blocking layer 88, and the surface of the current diffusion layer 87 faces the current blocking layers 66 and 68.
A p-type electrode 11 made of AuZn is arranged.

Here, the layer thickness of each of the first current diffusion layer 87a and the second current diffusion layer 87b is 2.5 μm, and the carrier concentration of the dopant Zn is 5 × 10 ¹⁸ cm ^−3. Has become.

In the eighth embodiment, in addition to the structure of the sixth embodiment, the current diffusion layer has a two-layer structure and the current blocking layers 66 and 68 are provided between them. Therefore, the second current diffusion layer 87 is provided.
The current that has spread to the peripheral portions of the current blocking layers 66 and 68 immediately below the electrodes at b is further spread at the first current diffusion layer 87a, which has the effect of further expanding the light emitting region.

(Ninth Embodiment) FIG. 9 is a diagram showing a sectional structure of a light emitting diode (semiconductor light emitting element) according to a ninth embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same parts as the light emitting diode 1001 of the first embodiment.

Reference numeral 1009 denotes a light emitting diode according to the ninth embodiment, in which the current element layer 96 has high resistance and a GaInP layer is used as the protective layer 95. Other configurations are the same as those of the light emitting diode 1001 of the first embodiment.

That is, the protective layer 95 is a p-type Ga _1-y In _y P layer.
The composition ratio y is y = 0.5, the carrier concentration of the dopant Zn is 5 × 10 ¹⁸ cm ⁻³ ,
The layer thickness is 0.1 μm.

The p-type current blocking layer 96 is made of (Al _x G
a _1-x ) _1-y In _y P layer (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) layer, and the composition ratios x and y are x = 0 and y =
It is 0.

Here, as a method of making the current blocking layer 96 have a high resistance, there are a method of not doping an impurity and a method of doping an impurity that easily forms a deep level, but a method suitable for a combination with growth conditions. Can be used. In the ninth embodiment, the current blocking layer 96 can have a high resistance by setting the growth temperature to 600 ° C. without doping impurities.

In the ninth embodiment, the above current diffusion layer 96 is used.
Since the current can be spread to the outside of the current blocking layer by utilizing, the light emission can be realized in a wide area of the active layer other than the region corresponding to the portion where the electrodes are arranged, and the high light emission efficiency is improved. A bright semiconductor light emitting device can be obtained.

Further, in this embodiment, the current blocking layer 9
Since it is not necessary to control the conductivity type and carrier concentration of No. 6, the growth process can be simplified.

(Embodiment 10) FIG. 10 is a diagram showing a sectional structure of a light emitting diode (semiconductor light emitting element) according to Embodiment 10 of the present invention. In the figure, the same reference numerals as those in FIG. 9 denote the same parts as the light emitting diode 1009 of the ninth embodiment.

Reference numeral 1010 denotes the light emitting diode of the tenth embodiment. In this light emitting diode 1010, the current diffusion layer has a two-layer structure, and the current blocking layer is provided between them. Other configurations are the same as those of the light emitting diode 1009 according to the ninth embodiment.
Is the same as

That is, the first GaP current diffusion layer 107a is formed on the p-type upper cladding layer 4 forming the light emitting portion 3a, and the surface of the current diffusion layer 107a is covered with the p-type protection layer 95. ing. A high resistance GaP current blocking layer 96 is disposed on a predetermined region of the surface of the protective layer 95. A second p-type GaP current spreading layer 107b is formed on the protective layer 95 and the current blocking layer 96, and the surface of the current spreading layer 107b is opposed to the current blocking layer 96. , AuZn p-type electrode 11
1 is arranged.

Here, the layer thickness of each of the first current diffusion layer 107a and the second current diffusion layer 107b is 2.5 μm.
The carrier concentration of the dopant Zn is 5 × 10 ¹⁸ cm ⁻³ .

In the tenth embodiment, the effect of spreading the current to the outside of the current blocking layer 96 by the high resistance current blocking layer 96 is the same as in the ninth embodiment. In addition to the effect of the ninth embodiment, since the current diffusion layer has a two-layer structure and the current blocking layer 96 is provided between the two layers, the second current diffusion layer 107b is located in the peripheral portion of the current blocking layer immediately below the electrode. The current that has spread to the first current diffusion layer 107a is further spread, and the light emitting region in the active layer can be further expanded.

(Embodiment 11) FIG. 11 is a diagram showing a sectional structure of a light emitting diode (semiconductor light emitting element) according to an embodiment 11 of the invention. In the figure, the same reference numerals as those in FIG. 1 denote the same parts as the light emitting diode 1001 of the first embodiment.

Reference numeral 1011 denotes the light emitting diode of the eleventh embodiment. In this light emitting diode 1011, a ZnMgSSe layer is used as the current diffusion layer 117, and a p-type ZnTe contact layer 119 is provided on the current diffusion layer 117. Thus, the p-type electrode 11 made of AuZn is provided. Other configurations are the same as those shown in the first embodiment.

That is, the current spreading layer 117 is formed of (Zn _x M
g _1-x ) S _1-y Se _y (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) layer, and the composition ratio x, y is x = 0.85, y
= 0.85, the carrier concentration of the dopant Zn is 1 x 10
^{It is 18} cm ⁻³ and the layer thickness is 5 μm.

The p-type ZnTe contact layer 11 is also used.
No. 9 has a carrier concentration of the dopant N (nitrogen) of 1 ×
It is 10 ¹⁸ cm ⁻³ and the layer thickness is 0.5 μm.

When a voltage was applied in the forward direction to the semiconductor light emitting device according to this example and a current was applied, a peak wavelength of 585n was obtained.
Luminous intensity of more than 7 cd was obtained at m.

The composition of the active layer is (Al _x Ga _{1 -x} )
_{When it was set to 1-y} In _y P (x = 0.50, y = 0.50), pure green light emission exceeding 5 cd was obtained at a peak wavelength of 555 nm.

In the eleventh embodiment, the current spreading layer 117 is used.
As (Zn _x Mg _1-x ) S _1-y Se _y (0 ≦ x ≦ 1,0
Since the ≦ y ≦ 1) layer is used, since it does not contain Al like the GaP layer, the current diffusion layer is not oxidized. In addition, the composition makes it possible to make the bandgap larger than that of the GaP current diffusion layer of the first embodiment, and therefore, the absorption of light emission from the active layer in the current diffusion layer can be further reduced, and the high light emission efficiency due to the increased light extraction efficiency. The semiconductor light emitting device of was obtained.

In addition, (Zn _x Mg _1-x ) S _1-y Se _y (0
In the case of ≦ x ≦ 1, 0 ≦ y ≦ 1), the lattice matching with the GaAs substrate and the light emitting portion is possible, and therefore the adverse effect of the lattice mismatch with the light emitting portion is not exerted.

The growth temperature of the ZnMgSSe layer is as low as 600 ° C., and re-diffusion in the light emitting portion can be suppressed during the formation process of the current diffusion layer.

In the eleventh embodiment, the ZnMgSSe layer is used as the current diffusion layer, but a ZnTe layer may be used as the current diffusion layer, and in this case also, the above-described eleventh embodiment. The same effect as can be obtained.

(Embodiment 12) FIG. 12 is a diagram showing a sectional structure of a light emitting diode (semiconductor light emitting element) according to Embodiment 12 of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same parts as the light emitting diode 1001 of the first embodiment.

Reference numeral 1012 denotes the light emitting diode of the twelfth embodiment, which is different from the light emitting diode 1001 of the first embodiment in that the current spreading layer 127 is composed of an n-type GaN layer, and the structure of other layers. Is the same as in the first embodiment.

The current spreading layer 127 is made of p-type Ga _1-y I
n _y N layers (0 ≦ y ≦ 1), for example, the composition y is y = 0, and the carrier concentration of the dopant Zn is 1
× 10 ¹⁸ cm ^-3 , and its layer thickness is 5 μm.

When a voltage was applied in the forward direction to the semiconductor light emitting device according to this example and a current was applied, a peak wavelength of 585n was obtained.
Luminous intensity of more than 7 cd was obtained at m.

The composition of the active layer is (Al _x Ga _{1 -x} )
_{When it was set to 1-y} In _y P (x = 0.50, y = 0.50), pure green light emission exceeding 5 cd was obtained at a peak wavelength of 555 nm.

In the twelfth embodiment, the current spreading layer 12 is
Since a Ga _1-y In _y N layer (0 ≦ y ≦ 1) layer was used for 7,
The composition makes it possible to make the bandgap larger than that of the GaP layer of the first embodiment. Therefore, the absorption of light emitted from the active layer in the current diffusion layer can be reduced, and the high efficiency of the semiconductor light emitting device can be achieved due to the increased light extraction efficiency. Was obtained.

In addition, (Al _x Ga _1-x ) is added to the current diffusion layer.
_{Even if a 1-y} In _y N layer (0 <x ≦ 0.3, 0 ≦ y ≦ 1) layer is used, if the Al composition is 0.3 or less, there is almost no oxidation and the band gap can be increased. Further, the absorption of light emitted from the active layer can be further reduced, and a high-brightness semiconductor light emitting device can be obtained by increasing the light extraction efficiency.

In addition, since the GaN current spreading layer does not require a contact layer, the electrode forming process can be simplified by eliminating the contact layer growth step and the etching step.

(Embodiment 13) FIG. 13 is a diagram showing a sectional structure of a light emitting diode (semiconductor light emitting element) according to Embodiment 13 of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same parts as the light emitting diode 1001 of the first embodiment.

Reference numeral 1013 denotes the light emitting diode of the thirteenth embodiment. In this light emitting diode 1013, the current diffusion layer 137 has an Al composition having a bandgap larger than that of the compound semiconductor material forming the light emitting portion 3a and 0.3 or less. (A
l _x Ga _1-x ) _1-y In _y P layer (0 <x ≦ 0.3, 0 ≦ y ≦
1) Layers are used. In addition, AuZ is formed on the current diffusion layer 137 via a p-type GaAs contact layer 139.
A p-type electrode 11 made of n is arranged. Other configurations are the same as those of the first embodiment.

The current diffusion layer 137 is made of p-type (Al _x G
a _1-x ) _1-y In _y P layer (0 <x ≦ 0.3, 0 ≦ y ≦ 1)
And the composition ratio x, y is x = 0.1,
y = 0.1, the carrier concentration of the dopant Zn is 5 × 10
^{It is 18} cm ⁻³ and its layer thickness is 5 μm. Further, the p-type GaAs contact layer 139 has the dopant Z
The carrier concentration of n is 5 × 10 ¹⁸ cm ⁻³ , and the layer thickness is 0.1.
It is 5 μm.

In the thirteenth embodiment, the current spreading layer 13 is
(AlxGa _1-x ) _1-y In _y P layer (0 <x ≦ 0.
3,0 ≦ y ≦ 1) layer is used, the band gap can be made larger than that of the GaP current diffusion layer of the first embodiment depending on the composition, and therefore absorption of light emitted from the active layer in the current diffusion layer is further increased. A high-brightness semiconductor light-emitting device can be obtained by increasing the light extraction efficiency.

In the above current diffusion layer, if the Al composition was 0.3 or less, there was almost no oxidation, and a highly reliable and high-luminance semiconductor light emitting device was obtained.

The present invention is not limited to the above embodiments. In the above embodiment, the Al composition of the active layer is 0.3 or 0.5.
By changing the composition, light emission in the visible light range from red to green can be obtained. Therefore, Al
It goes without saying that the effect of the present invention can be obtained even if the composition is changed. This also applies to other cladding layers, current blocking layers, and current diffusion layers.

The compound semiconductor material forming the current diffusion layer has a band gap larger than that of the active layer and does not contain Al or is a compound semiconductor having an Al composition of 0.3 or less. But it's okay.

The current blocking layer preferably has a bandgap larger than that of the active layer, but the material is not limited to this and other materials may be used.

Although the substrate is n-type in each of the above-mentioned embodiments, the substrate may be p-type and each semiconductor layer forming the light-emitting diode may be of a conductivity type opposite to that of each of the above-mentioned embodiments. In addition, the present invention can be implemented with various modifications without departing from the scope of the invention.

[0175]

As described above, according to the semiconductor light emitting device of the present invention (Claim 1), it is possible to realize light emission in a wide area other than directly below the electrode of the active layer, and improve the light extraction efficiency. Thus, a high-luminance semiconductor light emitting device can be obtained.

Further, since the current diffusion layer is made of a compound semiconductor having a bandgap larger than that of the light emitting portion, light from the active layer is not absorbed by the current diffusion layer, and the brightness of the semiconductor light emitting device is further enhanced. Can be achieved.

In addition, Al is used as a constituent element in the current diffusion layer.
As the current diffusion layer is not oxidized,
It is possible to improve reliability as compared with an element using a GaAs current diffusion layer.

According to the present invention (Claim 2), in addition to the structure of the semiconductor light emitting element according to Claim 1, two current diffusion layers of the second conductivity type are provided, and a current diffusion layer of the first conductivity type is provided therebetween. Since the current blocking layer is provided, the current spreading in the current spreading layer on the electrode side to the periphery of the current blocking layer directly below the electrode is further spread in the current spreading layer on the light emitting part side, and the light emitting region is further expanded. There is also an effect that can be.

According to the present invention (Claim 3), since the semiconductor layer of the same conductivity type as the current diffusion layer is used as the current blocking layer and the current is blocked by utilizing the difference of the hetero barrier, the light emitting section is provided. Each of the upper semiconductor layers can be formed by growing semiconductor crystals of the same conductivity type, which simplifies the manufacturing process and adversely affects the re-diffusion of impurities of the opposite conductivity type into the already grown semiconductor layer. Can be prevented.

According to the present invention (Claim 4), in addition to the structure of Claim 3, two current diffusion layers of the second conductivity type are provided, and a current is blocked by utilizing the difference in hetero barrier between them. The current spreading layer on the electrode side spreads the current spreading to the periphery of the current blocking layer directly below the electrode in the current spreading layer on the electrode side, and further spreads on the current spreading layer on the light emitting portion side, thereby further improving the light emitting region. There is also the effect that it can be expanded.

According to the present invention (Claim 5), since the current blocking layer is composed of the high resistance layer, it is not necessary to control the conductivity type and carrier concentration of the current blocking layer, and therefore the manufacturing process can be simplified. At the same time, it is possible to prevent adverse effects due to rediffusion of impurities for determining the conductivity type of the current blocking layer into the already grown semiconductor layer.

According to the present invention (Claim 6), in addition to the structure of Claim 5, two second conductivity type current diffusion layers are provided, and a high resistance current blocking layer is provided therebetween. Therefore, the current spreading in the current diffusion layer on the electrode side to the peripheral portion of the current blocking layer directly below the electrode is further spread in the current diffusion layer on the light emitting portion side, and there is also an effect that the light emitting region can be further widened.

According to the present invention (Claim 7), since the current diffusion layer is composed of the GaP layer, since the current diffusion layer does not contain Al, the reliability due to the oxidation of the current diffusion layer is high. The reliability can be improved significantly without any decrease in In addition, the GaP layer has a larger bandgap than AlGaAs used as a current diffusion layer in the conventional LED, and can reduce absorption of light emitted from the light emitting portion. Therefore, light extraction efficiency is further improved and high-brightness semiconductor light emission is achieved. The device is obtained. In addition, since the GaP layer can be directly provided with an electrode, the contact layer set in the conventional example is unnecessary, the number of steps can be reduced, and a significant cost reduction can be realized.

According to the present invention (claim 8), the current spreading layer is formed of (Zn _x Mg _1-x ) S _1-y Se _y (0 ≦ x ≦ 1, 0 ≦ y ≦
1) layer or ZnTe layer, the current diffusion layer does not contain Al as in the case of claim 7, so that reliability is not deteriorated due to oxidation and the reliability is significantly improved. You can In addition, (Zn _x Mg _1-x ) S _{1- y}
Since the Se _y layer or the ZnTe layer can have a larger band gap than the GaP layer, it is possible to further reduce the absorption of light emitted from the light emitting portion, and thus a semiconductor light emitting device with high brightness can be obtained. In addition, (Zn _x Mg _1-x ) S
_{Since the 1-y} Se _y layer or the ZnTe layer can be lattice-matched with the GaAs substrate and the light emitting portion, it is possible to avoid an adverse effect due to lattice mismatch with the light emitting portion.

According to the present invention (Claim 9), the current diffusion layer is composed of a Ga _1-y In _y N (0 ≦ y ≦ 1) layer. Since the diffusion layer does not contain Al, there is no reduction in reliability due to oxidation of the current diffusion layer, and the reliability can be greatly improved. Further, since the Ga _1-y In _y N layer can have a larger band gap than the GaP layer, absorption of light emitted from the light emitting portion can be further reduced, and a high-luminance semiconductor light emitting device can be obtained.

According to the present invention (claim 10), a Ga _1-y In _y P protective layer (0 ≦ y ≦ is provided between the current blocking layer and the light emitting portion.
Since (1) is provided, (Al _x Ga _1-x ) before regrowth
Prevents the oxidation due to exposure _1-y In _y P cladding layer, enables selective etching during etching of the current blocking layer can greatly simplify the manufacturing process.

According to the present invention (claim 11), the current blocking layer is formed of an Al _x Ga _1-x As (0 ≦ x ≦ 1) layer or an (Al _x Ga _1-x ) _1-y In _y P layer. (0 <x ≦ 1, 0 <y ≦
1) layer, and the protective film is formed of Ga _1-y In _y P (0
≦ y ≦ 1) layer, so as a etchant for etching the current blocking layer, a phosphoric acid-based solution such as H ₂ PO ₃ or a mixed solution of sulfuric acid and hydrogen peroxide solution (sulfuric acid:
H ₂ O ₂ : H ₂ O set to a predetermined ratio) or aqua regia (mixed solution of hydrochloric acid and nitric acid)
Since a difference in etching rate occurs between the protective film and the current blocking layer, selective etching of the current blocking layer can be easily performed.

According to the present invention (Claim 12), since the current diffusion layer is composed of a compound semiconductor having a bandgap larger than that of the light emitting portion and having an Al composition of 0.3 or less, the current diffusion layer containing Al. Is relatively less likely to oxidize, which has the effect that the reliability of the device is less likely to decrease.

According to the present invention (Claim 13), the current diffusion layer is composed of an AlGaInP layer having a bandgap larger than that of the light emitting portion and an Al composition of 0.3 or less. Therefore, the current diffusion layer is not easily oxidized. It is possible to prevent deterioration of reliability.

The AlGaInP layer has an Al composition of 0.
Even if it is 3 or less, it is possible to set the bandgap larger than that of AlGaAs used as a current diffusion layer in a conventional LED, and it is possible to reduce absorption of light emitted from the light emitting portion, thereby improving light extraction efficiency. Thus, a high-luminance semiconductor light emitting device can be obtained. In addition, AlGaI
Since the nP layer can be lattice-matched with the GaAs substrate and the light emitting portion, there is an effect that there is no adverse effect due to the lattice mismatch with the light emitting portion.

According to the present invention (Claim 14), the current diffusion layer is composed of an AlGaInN layer having a band gap larger than that of the light emitting portion and an Al composition of 0.3 or less. Even if the Al composition of the semiconductor is 0.3 or less, the band gap can be made larger than that of GaP, and in addition to suppressing the oxidation of the current diffusion layer, the absorption of light emitted from the light emitting portion in the current diffusion layer is also possible. It is possible to obtain a high-brightness semiconductor light emitting device in which the light emission efficiency is further improved.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a semiconductor light emitting device according to a first embodiment of the present invention, and FIGS. 1 (a) to 1 (d) are
The manufacturing process of the semiconductor light emitting device is shown in the order of steps.

FIG. 2 is a sectional view showing a structure of a semiconductor light emitting device according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a structure of a semiconductor light emitting device according to a third embodiment of the present invention.

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

FIG. 5 is a sectional view showing a structure of a semiconductor light emitting device according to a fifth embodiment of the present invention.

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

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

FIG. 8 is a sectional view showing a structure of a semiconductor light emitting device according to an eighth embodiment of the present invention.

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

FIG. 10 is a sectional view showing a structure of a semiconductor light emitting device according to a tenth embodiment of the present invention.

FIG. 11 is a sectional view showing a structure of a semiconductor light emitting device according to an eleventh embodiment of the present invention.

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

FIG. 13 is a sectional view showing a structure of a semiconductor light emitting device according to a thirteenth embodiment of the present invention.

FIG. 14 is a sectional view showing a structure of a conventional semiconductor light emitting device.

FIG. 15 is a cross-sectional view showing the structure of a semiconductor light emitting element using a conventional current blocking layer.

[Explanation of symbols]

1 n-GaAs substrate 2 n-lower clad layer 3,33 active layer 3a, 33a light emitting part 4 p-upper clad layer 5,45,75,95 protective layer 6,26,36,46,56,66,68, 76,96
Current blocking layer 7, 57, 58, 87a, 87b, 107a, 107
b, 117, 127, 137 current diffusion layer 10 n-type electrode 11 p-type electrode 139 p-type contact layer 1001 to 1013 semiconductor light emitting device

Claims (14)

[Claims] 1. A first-conductivity-type compound semiconductor substrate, and a light-emitting section formed by sequentially forming at least a first-conductivity-type cladding layer, an active layer, and a second-conductivity-type cladding layer on the compound-semiconductor substrate. A first conductivity type current blocking layer disposed on a predetermined region of the light emitting portion, a second conductivity type current spreading layer formed on the light emitting portion and the first conductivity type current blocking layer, A light extraction side electrode arranged to face the current blocking layer on the current diffusion layer, the current blocking layer blocking a current flow between the light extraction side electrode and the light emitting portion. The current diffusion layer diffuses the current so that the cross-sectional area of the current path between the light extraction side electrode and the light emitting portion becomes wider toward the light emitting portion side, and constitutes the light emitting portion. Al-free compound with a larger bandgap than semiconductor materials A semiconductor light emitting device composed of a semiconductor. 2. A first-conductivity-type compound semiconductor substrate, and a light-emitting portion formed by sequentially forming at least a first-conductivity-type clad layer, an active layer, and a second-conductivity-type clad layer on the compound semiconductor substrate. A first current diffusion layer of a second conductivity type formed on the light emitting portion, and a first conductivity type of a first conductivity type disposed on the first current diffusion layer so as to face a predetermined region of the light emitting portion. A current blocking layer, and a second current diffusion layer and a second current blocking layer formed on the current blocking layer.
A conductive type second current spreading layer; and a light extraction side electrode arranged on the second current spreading layer so as to face the current blocking layer, wherein the current blocking layer is the light extraction side. Current flow is blocked between the electrode and the light emitting portion, and the first and second current diffusion layers each have a cross-sectional area of a current path between the light extraction side electrode and the light emitting portion, The current is diffused so that it spreads as it approaches the light emitting part side,
A semiconductor light emitting device in which the both current diffusion layers are made of a compound semiconductor that does not contain Al having a band gap larger than that of a semiconductor material forming the light emitting portion. 3. A first-conductivity-type compound semiconductor substrate, and a light-emitting section formed by sequentially forming at least a first-conductivity-type cladding layer, an active layer, and a second-conductivity-type cladding layer on the compound-semiconductor substrate. A second conductive type current blocking layer disposed on a predetermined region of the light emitting section, a second conductive type current spreading layer formed on the light emitting section and the current spreading layer, and on the current spreading layer An electrode on the light extraction side arranged to face the current blocking layer, wherein the current blocking layer blocks a current flow between the light extraction side electrode and the light emitting portion, A hetero barrier larger than a hetero barrier between the light emitting portion and the current diffusion layer is formed between the current blocking layer and the light emitting portion, and the current diffusion layer includes the light extraction side electrode and the light emitting portion. The cross-sectional area of the current path between the two becomes wider toward the light emitting part side. A semiconductor light emitting element made of a compound semiconductor that does not contain Al and has a bandgap larger than that of the semiconductor material forming the light emitting portion. 4. A first-conductivity-type compound semiconductor substrate, and a light-emitting portion formed by sequentially forming at least a first-conductivity-type clad layer, an active layer, and a second-conductivity-type clad layer on the compound semiconductor substrate. A first current spreading layer of a second conductivity type formed on the light emitting portion, and a second conductivity type arranged on the first current spreading layer so as to face a predetermined region of the light emitting portion. Current blocking layer, and a second current diffusion layer and a second current blocking layer formed on the current blocking layer.
A second current spreading layer of conductivity type; and a light extraction side electrode formed on the second current spreading layer so as to face the current blocking layer, wherein the current blocking layer is the light extraction side. A current barrier is blocked between the electrode and the light emitting portion, and a hetero barrier larger than a hetero barrier between the light emitting portion and the current diffusion layer is formed between the current blocking layer and the light emitting portion. The first and second current diffusion layers diffuse the current so that the cross-sectional area of the current path between the light extraction side electrode and the light emitting portion becomes wider toward the light emitting portion side. And both of the current diffusion layers are made of a compound semiconductor that does not contain Al having a bandgap larger than that of the semiconductor material forming the light emitting portion. 5. A first-conductivity-type compound semiconductor substrate, and a light-emitting portion formed by sequentially forming at least a first-conductivity-type cladding layer, an active layer, and a second-conductivity-type cladding layer on the compound-semiconductor substrate. A current blocking layer disposed on a predetermined region of the light emitting portion, a second conductivity type current spreading layer formed on the light emitting portion and the current blocking layer, and a current blocking layer on the current spreading layer. A compound semiconductor that comprises a light-extraction-side electrode arranged so as to face each other, and the current-blocking layer constitutes the current-spreading layer so as to block current flow between the light-extraction-side electrode and the light-emitting portion. The resistance of the current diffusion layer is higher than that of the current diffusion layer, and the current diffusion layer diffuses the current such that the cross-sectional area of the current path between the light extraction side electrode and the light emitting portion becomes wider toward the light emitting portion side. From the semiconductor material that constitutes the light emitting portion A semiconductor light emitting device composed of a compound semiconductor having a large band gap and not containing Al. 6. A first-conductivity-type compound semiconductor substrate, and a light-emitting portion formed by sequentially forming at least a first-conductivity-type cladding layer, an active layer, and a second-conductivity-type cladding layer on the compound-semiconductor substrate. A first current spreading layer of a second conductivity type formed on the light emitting portion, and a current blocking layer arranged on the first current spreading layer so as to face a predetermined region of the light emitting portion. A second current diffusion layer and a second current blocking layer formed on the current blocking layer
A second current spreading layer of conductivity type; and a light extraction side electrode formed on the second current spreading layer so as to face the current blocking layer, wherein the current blocking layer is the light extraction side. The resistance is higher than that of the compound semiconductor forming the current diffusion layer so as to block the flow of current between the electrode and the light emitting portion, and the first and second current diffusion layers are respectively The current is diffused so that the cross-sectional area of the current path between the light extraction side electrode and the light emitting portion becomes wider toward the light emitting portion side,
A semiconductor light emitting device in which the both current diffusion layers are made of a compound semiconductor that does not contain Al having a band gap larger than that of a semiconductor material forming the light emitting portion. 7. The semiconductor light emitting device according to claim 1, wherein the current diffusion layer is a GaP layer. 8. The current spreading layer is (Zn _x Mg _1-x ) S
_1-y Se _y (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) layer or ZnT
The semiconductor light emitting device according to claim 1, which is an e layer. 9. The current spreading layer is a Ga _{1 -y} In _y N layer (0
The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting device is a ≦ y ≦ 1) layer. 10. The surface of the second-conductivity-type cladding layer on the upper side of the active layer forming the light-emitting portion is covered with a protective film, and the protective film covers the semiconductor material forming the current blocking layer. 7. The semiconductor light emitting device according to claim 1, which is made of a semiconductor material having etching selectivity. 11. The semiconductor light emitting device according to claim 10, wherein the current blocking layer is an Al _x Ga _1-x As (0 ≦ x ≦ 1) layer or an (Al _x Ga _{1 -x} ) _1-y In _y. P (0 <x ≦ 1,0
<Y ≦ 1) layer, and the protective film is a Ga _1-y In _y P (0 ≦ y ≦ 1) layer. 12. The current diffusion layer is made of a compound semiconductor having an Al composition of 0.3 or less, which has a bandgap larger than that of a semiconductor material forming the light emitting portion.
7. The semiconductor light emitting device according to any one of 1 to 6. 13. The current spreading layer is (Al _x Ga _1-x )
13. The semiconductor light emitting device according to claim 12, which is a _1-y In _y P (0 <x ≦ 0.3, 0 ≦ y ≦ 1) layer. 14. The current spreading layer is (Al _x Ga _{1 -x} )
13. The semiconductor light emitting device according to claim 12, which is a _1-y In _y N (0 <x ≦ 0.3, 0 ≦ y ≦ 1) layer.