JP2002353499A - Semiconductor light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor light-emitting device that has high luminance, and solves the problem of transparent conductive layer peeling off, due to dicing or the like. SOLUTION: This semiconductor light-emitting device has multilayered structure (in the case of transparent conductive layers 6 and 7), or gradient composition structure (in the case of a transparent conductive layer 8). In the multilayer structure, a light-emitting section layer 12 comprising an active layer 3 held between first and second conductivity type cladding layers 2 and 4, a transparent conductive layer 6, 7, or 8 made of a metal oxide, electrodes 9 and 10 are formed on a first conductivity-type substrate 1, and at least two transparent conductive layers are provided. In the gradient composition structure, the composition changes gradually. Preferably, a second conductivity-type current dispersion layer 5 and/or a compound semiconductor layer 11 are formed between the light-emitting section layer 12 and the transparent conductive layer.

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 having a transparent conductive layer, and more particularly to a semiconductor light emitting device having a metal oxide transparent conductive layer having high luminance, low manufacturing cost, and having no problem of peeling.

[0002]

2. Description of the Related Art Conventional light emitting diodes (LEDs)
Most of them were aP-based green light emitting diodes and AlGaAs-based red light emitting diodes. However, recently, GaN and AlGaInP
A technique for growing a system-based crystal layer by metal organic chemical vapor deposition (MOVPE) has been developed, and high-brightness light-emitting diodes of orange, yellow, green, and blue can be manufactured.

[0003] When an epitaxial wafer formed by the MOVPE method is used, it is possible to manufacture an LED which emits light of a short wavelength and high luminance, which have been impossible so far. Figure 5 shows the conventional L
1 shows an example of a cross-sectional structure of an ED. This LED is an n-type GaAs substrate 1
A light emitting portion layer 12 having a double hetero structure composed of an n-type AlGaInP cladding layer 2 / an undoped AlGaInP active layer 3 / p-type AlGaInP cladding layer 4 on the first main surface. Further, a current dispersion layer 5 made of p-type GaP or the like is formed on the p-type cladding layer 4, and a transparent conductive layer 6 is formed thereon. A surface electrode 9 (light extraction side) made of Au or the like is formed on a part of the surface of the transparent conductive layer 6, and Au is formed on the entire second main surface of the substrate 1.
An electrode 10 (substrate-side electrode) made of a Ge alloy or the like is formed.

In order to obtain high-luminance light emission from the LED having this structure, it is necessary to increase the current injected from the surface electrode 9 of the light emitting element to the light emitting element. However, the active layer 3 made of a p-type semiconductor generally has a specific resistance. Therefore, the current injected from the surface electrode 9 into the active layer 3 becomes dense near the electrode 9. Electrode 9
Since light emission concentrates on a portion where the current is nearby, it is necessary to make the current distribution uniform in the light emitting portion layer in order to prevent local concentration of the current and obtain a high-brightness LED. Therefore, a current dispersion layer made of a substance having a low resistance and having a small absorption at the emission wavelength is provided between the light emitting portion layer and the electrode.

However, the GaP used for the current dispersion layer 5 does not have a very high carrier density and has a relatively high specific resistance. For this reason, in order to obtain a sufficient current dispersing action, it is necessary to grow the GaP layer thickly. For example, p-type Ga
In the case of P (Zn doping amount 1 × 10 ¹⁸ cm ⁻³ ), the film thickness needs to be about 50 μm or more. However, increasing the thickness of the GaP layer increases the manufacturing cost of the LED.

To reduce the cost of the LED, it is only necessary to make the current dispersion layer thinner. However, this requires an epitaxial layer having a low resistance, and a high carrier concentration layer is required.
However, with a semiconductor material such as AlGaInP or GaN, it is difficult to grow a p-type epitaxial layer having a high carrier concentration. Any other semiconductor that satisfies this condition may be used, but no semiconductor having such characteristics has been found.

For this reason, various proposals have been made for a low-resistance current spreading layer. One of them is to use a metal thin film as a transparent conductive layer for a GaN-based LED (Japanese Patent Laid-Open No. 10-1).
73224). However, it is necessary to make the metal thin film extremely thin in order to sufficiently enhance the light transmittance, and the metal thin film does not have low resistance. On the other hand, if the resistance is to be kept low, the thickness of the metal thin film is limited, and the light transmittance is poor.

A metal oxide such as indium tin oxide (ITO) is known as a material that satisfies sufficient translucency and conductivity necessary for obtaining sufficient current dispersion. When an ITO film is used as a current spreading layer, a conventional thick semiconductor current spreading layer is not required, so that a low-cost and high-brightness LED can be obtained. Examples of LEDs having an ITO film between the light extraction side surface electrode and the light emitting section layer are described in U.S. Pat.
It is described in JP-A-11-4020.

However, it has been found that in an LED in which an ITO film is formed on an epitaxial wafer, there is a problem that the ITO film is peeled off in a process such as dicing. Therefore, it has been difficult to commercialize an LED having an ITO film on an epitaxial wafer. Therefore, development of a semiconductor light emitting device using a metal oxide-based transparent conductive layer such as ITO and having no problem of peeling from an epitaxial wafer at the time of dicing is desired.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a semiconductor light emitting device which has high luminance and has no problem of peeling of a transparent conductive layer due to dicing or the like.

[0011]

Means for Solving the Problems As a result of intensive studies in view of the above-mentioned objects, the present inventors have found that the present inventors have found that the light emitting portion layer (the current distribution layer and / or
Or, if a compound semiconductor layer is provided, on it)
Instead of forming a single layer of transparent conductive layer, by forming two or more transparent conductive layers having different compositions or forming a transparent conductive layer whose composition gradually changes, the transparent conductive layer at the time of dicing is formed. They discovered that peeling could be suppressed, and reached the present invention.

That is, a first semiconductor light emitting device according to the present invention is a light emitting unit comprising an active layer sandwiched between a first conductive type clad layer and a second conductive type clad layer on a first conductive type substrate. A transparent conductive layer made of a metal oxide; and an electrode, wherein the transparent conductive layer has a multilayer structure of two or more layers.

A second semiconductor light emitting device according to the present invention comprises a light emitting portion layer comprising an active layer sandwiched between a first conductive type clad layer and a second conductive type clad layer on a first conductive type substrate. A transparent conductive layer made of a metal oxide and an electrode are formed, and the transparent conductive layer has a gradient composition structure in which the composition gradually changes.

In any of the first and second semiconductor light emitting devices, a current spreading layer and / or a compound semiconductor layer of the second conductivity type may be formed between the light emitting portion layer and the transparent conductive layer. good.

In one preferred embodiment of the present invention, the transparent conductive layer on the light emitting portion layer side is made of SnO ₂ or at least one of Sb and F.
Consists SnO ₂ containing species element, a transparent conductive layer on the surface electrode side is made of In ₂ O ₃ or Sn-doped In ₂ O _3.

In another preferred embodiment of the present invention, the transparent conductive layer on the light emitting portion layer side is made of ZnO or ZnO containing at least one element selected from the group consisting of Al, In and F, and has a surface. The transparent conductive layer on the electrode side is made of ITO.

In yet another preferred embodiment of the present invention,
The transparent conductive layer on the light emitting portion layer side is made of Zn ₂ SnO ₄ , and the transparent conductive layer on the surface electrode side is made of ITO.

In yet another preferred embodiment of the present invention,
The transparent conductive layer on the light emitting portion layer side is made of TiO ₂ , and the transparent conductive layer on the surface electrode side is made of ITO.

The substrate is made of GaAs, and the active layer is made of AlGaIn.
It is preferably made of P or GaInP. Preferably, the current dispersion layer is made of at least one compound semiconductor selected from the group consisting of GaP, GaAlP, GaAlAs, GaAsP, AlGaInP, and AlInP.

The compound semiconductor layer may be made of (1) InP or InAs
(2) a ternary compound semiconductor of AlInAs or AlInP, and (3) at least one ternary compound semiconductor selected from the group consisting of AlGaAs, AlGaP, GaInAs, and GaInP (molar of Ga). (Ratio: 0.2 or less), (4) AlInAsP quaternary compound semiconductor, (5) AlGaInP, AlGaInAs, AlGaAsP and GaIn
At least one quaternary compound semiconductor selected from the group consisting of AsP (Ga molar ratio: 0.2 or less), or (6) AlGaInA
It is any of pentagonal compound semiconductors composed of sP (molar ratio of Ga: 0.2 or less).

[0021]

FIG. 1 is a sectional view showing a layer structure of a semiconductor light emitting device according to an embodiment of the present invention. In this embodiment, the first conductivity type is the n-type and the second conductivity type is the p-type, but the reverse is also possible.

On the first main surface of the n-type GaAs substrate 1, an n-type AlGaInP
A clad layer 2 is formed, an undoped AlGaInP active layer 3 is formed on the clad layer 2, and a p-type AlGaInP clad layer 4 is formed on the active layer 3. The n-type cladding layer 2, the active layer 3, and the p-type cladding layer 4 constitute a light emitting section layer 12 having a double hetero structure. In the embodiment of FIG. 1, the p-type current spreading layer 5 is formed on the light emitting section layer 12, but the current spreading layer 5 is not essential. A p-type front surface electrode 9 is partially formed on the transparent conductive layer 7, and an n-type back surface electrode 10 is formed on the back surface of the substrate 1.

The light emitting section layer 12 is composed of an AlGaInP mixed crystal having a pn junction type double hetero junction structure. Particularly, the indium composition ratio is set to about 0.5 (Al _x Ga _1-x ) _0.5 In _0.5 P
(0 ≦ x ≦ 1) is preferable because of lattice matching with the GaAs single crystal substrate 1. The thickness of each cladding layer 2, 4 is preferably 0.2
3.03.0 nm, more preferably 0.3-1.0 nm. Further, the thickness of the active layer 3 is preferably 0.2 to 1.0 nm, more preferably 0.6 to 1.0 nm.

The p-type current distribution layer 5 is usually made of p-type GaP, GaAl
It is made of at least one compound semiconductor selected from the group consisting of P, GaAsP, GaAlAs, AlGaInP, and AlInP. It is necessary that the compound semiconductor constituting the p-type current dispersion layer 5 has a small absorption at the emission wavelength and a low specific resistance. Generally red
In an orange light emitting diode, the current spreading layer 5 is made of GaAlAs, and in a yellow to green light emitting diode, the current spreading layer 5 is made of GaAlAs.
Is made of GaP or GaAsP. The current dispersion layer 5 is preferably as thin as possible.

In this embodiment, two transparent conductive layers 6 and 7 having different compositions are formed on the current distribution layer 5. Of course, the number of transparent conductive layers is not limited to two, and may be three or more.
The combination of the transparent conductive layers 6 and 7 includes (1) the transparent conductive layer 6
There consists SnO ₂ containing at least one element of the tin oxide (SnO ₂₎ or Sb and F, the transparent conductive layer 7 is In ₂ O ₃ or Sn
In the case where the transparent conductive layer 6 is made of doped indium oxide (In ₂ O ₃ ), the transparent conductive layer 6 is made of zinc oxide (ZnO) or ZnO containing at least one element selected from the group consisting of Al, In and F. (3) when the transparent conductive layer 7 is made of indium tin oxide (ITO), (3) when the transparent conductive layer 6 is made of zinc tin oxide (Zn ₂ SnO ₄ ), and (4) when the transparent conductive layer 7 is made of ITO. The transparent conductive layer 6 may be made of titanium oxide (TiO ₂ ), and the transparent conductive layer may be made of ITO.

In the case of (1), when the transparent conductive layer 6 contains at least one element of Sb and F, the content of the element is 1 to 10 atomic% with respect to the whole transparent conductive layer 6 as 100 atomic%. Preferably it is. When the transparent conductive layer 7 contains Sn, the content is 100 atomic% of the entire transparent conductive layer 7.
Is preferably 1 to 10 atomic%.

In the case (2), the transparent conductive layer 6 is made of Al, In and F
When at least one element selected from the group consisting of is contained, the content of the element is 10
It is preferably 1 to 10 atomic% as 0 atomic%.

The specific resistance of ITO is generally about 3 × 10 ⁻⁶ Ωm, which is about one hundredth of the specific resistance of the p-type GaP forming the current distribution layer 5. Therefore, when the transparent conductive layer 7 is made of ITO or a composition close to ITO, the thickness of the current dispersion layer 5 can be greatly reduced.

The transparent conductive layers 6 and 7 can be formed by a wet method in which a coating film is formed by a spin coater or the like and then a heat treatment, or a dry method such as a sputtering method or various vapor deposition methods.

Since the p-type front electrode 9 is used for wire bonding and the n-type back electrode 10 is used for die bonding, the p-type front electrode 9 and the n-type back electrode 10 have good bonding characteristics, Good ohmic characteristics and adhesion to the lower layer are required. Therefore, each of the electrodes 9 and 10 is preferably constituted by a plurality of metal layers. Each of the electrodes 9 and 10 may have an oxide layer. Further, each of the electrodes 9 and 10 preferably has a metal layer having good bonding characteristics, such as Au or Al, as the uppermost layer. For example, AuZn / Ni / Au is applied to the p-type surface electrode 9.
It is preferable to use an AuGe / Ni / Au laminated electrode for the n-type back electrode 10.

The metal layers of the electrodes 9 and 10 are formed by resistance heating evaporation,
It can be formed by an evaporation method such as an electron beam evaporation method.
Further, heat treatment (alloying) for imparting ohmic properties to each of the electrodes 9 and 10 may be performed. The oxide layer can be formed by various known film formation methods.

FIG. 2 is a sectional view showing a layer structure of a semiconductor light emitting device according to another embodiment of the present invention. n-type GaAs substrate 1,
Light emitting section layer 12 (n-type AlGaInP clad layer 2, undoped AlG
The aInP active layer 3 and the p-type AlGaInP cladding layer 4), the p-type current dispersion layer 5, the p-type front electrode 9 and the n-type back electrode 10 are the same as those of the semiconductor light emitting device of the embodiment of FIG. In this semiconductor light emitting device, the transparent conductive layer 8 has a gradually changing gradient composition. Even in the case of the graded composition, the composition of the surface on the light emitting portion layer 12 side (first composition) and the composition of the surface on the surface electrode 9 side (second composition) are the same as described above in (1) SnO ₂ ( Or Sb
And SnO ₂ ) / In ₂ O ₃ containing at least one element of F
Or Sn-doped In ₂ O _3, Zn containing at least one element selected from (2) ZnO (or Al, the group consisting of In and F
O) / ITO, (3) Zn ₂ SnO ₄ / ITO, and (4) TiO ₂ / ITO combinations.

The transparent conductive layer 8 can be formed, for example, by an alternate sputtering method using a first target having a first composition and a second target having a second composition. The rate of change of the composition of the transparent conductive layer 8 is obtained by gradually changing the ratio between the time for sputtering with the first target and the time for sputtering with the second target.
It can be set appropriately. That is, first, the first target is sputtered using 100% of the first target,
Next, the time for sputtering with the second target is gradually increased, and the time for sputtering with the first target is gradually decreased.
To perform sputtering.

The semiconductor light emitting device shown in FIG. 3 is the same as the semiconductor light emitting device of FIG. 1, except that a compound semiconductor layer 11 is formed between the current spreading layer 5 and the transparent conductive layer 6. Further, the semiconductor light emitting device shown in FIG. 4 has a configuration in which a compound semiconductor layer 11 is formed between the current distribution layer 5 and the transparent conductive layer 8
This is the same as the semiconductor light emitting device of FIG.

In any case, the compound semiconductor layer 11
(1) InP or InAs binary compound semiconductor, (2) AlInAs or AlInP ternary compound semiconductor, (3) AlGaAs, AlGaP, Ga
A ternary compound semiconductor of at least one selected from the group consisting of InAs and GaInP, wherein the molar ratio of Ga is 0.2 or less; (4) a quaternary compound semiconductor of AlInAsP; (5) AlGaIn
P, AlGaInAs, at least one selected from the group consisting of AlGaAsP and GaInAsP, and a quaternary compound semiconductor having a molar ratio of Ga of 0.2 or less, or (6) AlGaInAsP, wherein the molar ratio of Ga is 0.2 It is preferable to form the pentagonal compound semiconductor below. In the Ga-containing compound semiconductors (3) and (5), the molar ratio of Ga to the entire compound semiconductor 6 is preferably set to 0.2 or less. This is because the peeling of the layer 6 increases. A more preferred molar ratio of Ga is 0 to 0.15.

Type of Compound Semiconductor and Compound Semiconductor Layer 11
It is preferable to appropriately select the thickness and the like according to the conditions such as the emission wavelength and the luminance of the semiconductor light emitting element. Compound semiconductor layer 11
When a material having low transparency to the emission wavelength is used, the thinner the better, the better. When a material having excellent transparency is used, the thickness does not matter.

The compound semiconductor layer 11 can be formed by an epitaxial growth method, for example, a metal organic chemical vapor deposition method (M0VPE method).

The semiconductor light emitting device of the present invention may have a buffer layer (not shown) and a distributed Bragg reflection layer (DBR layer, not shown) between the substrate 1 and the n-type cladding layer 2. The buffer layer can be formed of n-type (Se-doped) GaAs. In addition, the substrate 1 of the light beam from the active layer 3 is formed by the DBR layer.
And the luminous efficiency of the semiconductor light emitting device can be increased.

[0039]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 A red light emitting diode chip having a structure shown in FIG. 1 and having a light emission wavelength of about 630 nm was manufactured by the following procedure.

First, on an n-type GaAs substrate 1 heated to 700 ° C.,
500nm thick n-type (Se-doped) GaAs buffer layer, 500n thickness
m n-type (Se-doped) (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 2
(Se doping amount: 1.0 × 10 ¹⁸ cm ⁻³ ) 600 nm thick undoped (Al _0.15 Ga _0.85 ) _0.5 In _0.5 P active layer 3, 500 nm thick p-type
(Zinc-doped) (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 4 (zinc-doped amount: 5 × 10 ¹⁷ cm ⁻³ ) and p-type (zinc-doped) GaP current dispersion layer 5 with a thickness of 2 μm (zinc-doped) Quantity: 5 × 10 ¹⁸ c
m ⁻³ ) were epitaxially grown in order by the MOVPE method. MOVPE growth up to the cladding layer 4 made of p-type AlGaInP was performed at a temperature of 700 ° C. and a pressure of 50 Torr at a growth rate of 0.3 to 1.0 nm / sec. The supplied ratio of group V element to group III element (V / III ratio) was in the range of 300 to 600. The GaP layer was formed under the conditions of a growth rate of 1 nm / sec and a V / III ratio of 100.

Using hydrogen as a carrier gas,
Trimethylaluminum as a source (TMA), trimethyl gallium as Ga source (TMG), trimethyl indium as an In source (TMI), arsine As source (AsH _3), phosphine as P source (PH _3), Zn Diethyl zinc (DEZ) as source and H ₂ S as Se source
e was used.

Next, a 150 nm thick transparent conductive layer 6 made of SnO ₂ containing 5% of Sb is formed on the epitaxial wafer by sputtering, and a 150 nm thick indium tin oxide (ITO) is further formed by sputtering. Was formed. Using a mask having a plurality of circular openings with a diameter of 150 μm on the transparent conductive layer 7, a 60 nm thick gold-zinc alloy, a 10 nm thick nickel,
Then, gold having a thickness of 1000 nm was sequentially deposited, and a plurality of circular p-type surface electrodes 9 having a diameter of 150 μm were formed on the entire surface of the transparent conductive layer 7 at equal intervals. The thickness of the n-type GaAs substrate 1 is
A 0 nm gold-germanium alloy, a 10 nm thick nickel and a 500 nm thick gold were sequentially deposited to form an n-type back electrode 10.

The transparent conductive layers 6, 7 thus produced
Then, the epitaxial wafer having the electrodes 9 and 10 is diced to a size of 300 μm square including one front electrode 9, fixed to a frame, wire-bonded to the front electrode 9, and die-bonded to the back electrode 10 to emit light. A diode chip was manufactured.

With respect to the obtained light emitting diode chip,
When the ratio of the light emitting diode chips showing the defect that the transparent conductive layers 6 and 7 were peeled off from the epitaxial layer was examined by a chip surface evaluation apparatus, it was 1% or less of the whole.

[0046]Example 2 Red light emission near 630 nm wavelength with the structure shown in Fig. 2
A diode chip was manufactured according to the following procedure. Example 1
Epitaxial wafer same as (emission wavelength: around 630nm)
While heating to 600 ℃, SnO_TwoThe first consisting of
Target and In_TwoO _ThreeAlternate with a second target consisting of
Depending on the sputtering method used, the composition is SnO_TwoFrom In
_TwoO_ThreeA transparent conductive layer 8 having a thickness of 300 nm which gradually changes
Was.

Using a mask having a plurality of circular openings each having a diameter of 150 μm on the transparent conductive layer 8, a gold film having a thickness of 60 nm is formed.
A zinc alloy, nickel having a thickness of 10 nm, and gold having a thickness of 1000 nm were sequentially deposited, and a plurality of circular p-type electrodes 9 having a diameter of 150 μm were formed on the entire surface of the transparent conductive layer 8 at equal intervals. N-type GaA
A 60 nm thick gold-germanium alloy, a 10 nm thick nickel and a 500 nm thick gold were sequentially deposited on the entire bottom surface of the s substrate 1 to form an n-type back electrode 10.

The epitaxial wafer provided with the transparent conductive layer 8 and the electrodes 9 and 10 thus manufactured is placed on the surface electrode 9
And the surface state of the light emitting diode was examined while being fixed to the frame. As a result, 1% of the light emitting diodes showed a defect that the transparent conductive layer 8 was peeled off from the epitaxial layer. .

EXAMPLE 3 A buffer layer, a first cladding layer 2, an active layer 3, a second cladding layer 4 and a current spreading layer 5 were epitaxially grown on a substrate 1 in the same condition as in Example 2 by MOVPE. I let it. On the obtained epitaxial wafer, the composition was changed from Sb / SnO ₂ by an alternate sputtering method using a first target composed of SnO ₂ containing 5% Sb and a _second target composed of In ₂ O _3. A transparent conductive layer 8 having a thickness of 300 nm and gradually changing to In ₂ O ₃ was formed.

After the same electrodes as in Example 1 were formed on the epitaxial wafer manufactured in this manner, the surface condition of the light emitting diode chip was examined by the same method as in Example 1, and the transparent conductive layer 8 was separated from the epitaxial layer. 1% of the light-emitting diodes exhibiting defective defects.

Comparative Example 1 A light emitting diode having a structure shown in FIG. First, the buffer layer, the first cladding layer 2, the active layer 3, the second cladding layer 4, and the current dispersion layer 5 were epitaxially grown on the substrate 1 in the same conditions as in Example 1 by MOVPE. An ITO film (transparent conductive layer 6) having a thickness of 300 nm was formed on the obtained epitaxial wafer by a sputtering method, and electrodes 9 and 10 were formed on both surfaces under the same conditions as in Example 1.

The transparent conductive layer (IT
O) Epitaxial wafer with 6 and electrodes 9, 10
Dicing was performed with a size of 300 μm square including one surface electrode 9, and the surface state of the light emitting diode chip was examined while being fixed to the frame. %
That was all.

As described above, the light emitting portion layer 12 having the double hetero structure is made of Al
Although the case of forming with GaInP has been described as an example, the present invention is not limited to this. For example, the present invention is also applicable to a semiconductor light emitting device using another compound semiconductor such as AlGaAs for the light emitting portion layer 12. In the case of a semiconductor light emitting device having the compound semiconductor layer 11, the peeling resistance of the transparent conductive layer is further improved.

[0054]

As described above in detail, the transparent conductive layer made of a metal oxide has a structure of two or more layers having different compositions.
With a gradient composition structure in which the composition gradually changes,
Peeling of the transparent conductive layer from the epitaxial wafer can be significantly suppressed. As a result, the thickness of the epitaxial wafer of the semiconductor light emitting device can be reduced to 1/5 to 1/10 that of the conventional semiconductor light emitting device, and the luminance can be reduced by about 50%.
% Can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a semiconductor light emitting device according to an embodiment of the present invention.

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

FIG. 3 is a cross-sectional view illustrating a semiconductor light emitting device according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a semiconductor light emitting device according to another embodiment of the present invention.

FIG. 5 is a sectional view showing a conventional semiconductor light emitting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... 1st cladding layer 3 ... Active layer 4 ... 2nd cladding layer 5 ... Current dispersion layer 6 ... 1st transparent conductive layer 7 ... 2nd transparent Conductive layer 8 ... Transparent conductive layer with gradient composition 9 ... Surface electrode 10 ... Back electrode 11 ... Compound semiconductor layer 12 ... Light emitting layer

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Kenji Shibata 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Prefecture F-term in the Hidaka Factory, Hitachi Cable, Ltd. 5F041 AA03 AA04 AA08 CA04 CA34 CA64 CA85 CA92 DA07

Claims (19)

[Claims] 1. A light emitting portion layer comprising an active layer sandwiched between a first conductive type clad layer and a second conductive type clad layer on a first conductive type substrate, and a transparent conductive layer made of a metal oxide. When,
A semiconductor light emitting device having electrodes formed thereon, wherein the transparent conductive layer has a multilayer structure of two or more layers. 2. The semiconductor light emitting device according to claim 1, wherein a current spreading layer of a second conductivity type is formed between said light emitting portion layer and said transparent conductive layer. . 3. The semiconductor light emitting device according to claim 1, wherein a compound semiconductor layer is formed between said light emitting portion layer and said transparent conductive layer. 4. The semiconductor light emitting device according to claim 2, wherein a compound semiconductor layer is formed between said current dispersion layer and said transparent conductive layer. 5. The semiconductor light emitting device according to claim 1, wherein the transparent conductive layer on the light emitting portion layer side is made of SnO _2.
Or SnO ₂ containing at least one element of Sb and F, and the transparent conductive layer on the surface electrode side is made of In ₂ O ₃ or Sn-doped I
A semiconductor light-emitting device comprising n ₂ O ₃ . 6. The semiconductor light emitting device according to claim 1, wherein the transparent conductive layer on the light emitting portion layer side is ZnO.
Or at least one selected from the group consisting of Al, In and F
A semiconductor light-emitting device comprising ZnO containing various kinds of elements, and wherein the transparent conductive layer on the surface electrode side is composed of ITO. 7. The semiconductor light emitting device according to claim 1, wherein the first transparent conductive layer on the light emitting portion layer side is
A semiconductor light emitting device comprising Zn ₂ SnO ₄ and a transparent conductive layer on the surface electrode side comprising ITO. 8. The semiconductor light emitting device according to claim 1, wherein the transparent conductive layer on the light emitting portion layer side is made of TiO _2.
Wherein the transparent conductive layer on the surface electrode side is made of ITO. 9. A light emitting portion layer comprising an active layer sandwiched between a first conductive type clad layer and a second conductive type clad layer on a first conductive type substrate, and a transparent conductive layer made of a metal oxide. When,
A transparent conductive layer having a gradient composition structure in which the composition gradually changes. 10. The semiconductor light emitting device according to claim 9, wherein a current spreading layer of a second conductivity type is formed between the light emitting portion layer and the transparent conductive layer. . 11. The semiconductor light emitting device according to claim 9, wherein a compound semiconductor layer is formed between the light emitting portion layer and the transparent conductive layer. 12. The semiconductor light emitting device according to claim 10, wherein a compound semiconductor layer is formed between the current dispersion layer and the transparent conductive layer. 13. The semiconductor light emitting device according to claim 9, wherein the composition of the transparent conductive layer is such that the light emitting portion layer side contains SnO ₂ or SnO ₂ containing at least one element of Sb and F. _2. A semiconductor light emitting device according to ₂ , wherein the surface electrode side is In ₂ O ₃ or Sn-doped In ₂ O ₃ , and the composition is gradually changed between the two. 14. The semiconductor light emitting device according to claim 9, wherein the composition of the transparent conductive layer is at least one selected from the group consisting of ZnO or Al, In, and F on the light emitting portion layer side. ZnO containing various elements, the surface electrode side is ITO
And a composition gradually changing between the two. 15. The semiconductor light-emitting device according to claim 9, wherein the composition of the transparent conductive layer is such that the light-emitting portion layer side is Zn ₂ SnO ₄ , the surface electrode side is ITO, and the composition is between the two. A semiconductor light-emitting device characterized in that the composition gradually changes. 16. The semiconductor light-emitting device according to claim 9, wherein the composition of the transparent conductive layer is such that the light-emitting portion layer side is TiO ₂ , the surface electrode side is ITO, and the composition is between the two. Is a semiconductor light emitting device characterized by a gradual change. 17. The semiconductor light emitting device according to claim 1, wherein said substrate is made of GaAs, and said active layer is made of AlGaInP or GaInP. 18. The semiconductor light emitting device according to claim 1, wherein the current distribution layer is formed of GaP, GaAlP, GaAlAs, or GaAs.
A semiconductor light emitting device comprising at least one compound semiconductor selected from the group consisting of P, AlGaInP, and AlInP. 19. The semiconductor light emitting device according to claim 3, wherein the compound semiconductor layer comprises: (1) a binary compound semiconductor of InP or InAs; and (2) a ternary compound semiconductor of AlInAs or AlInP. -Based compound semiconductor, (3) AlGaAs, AlGaP, GaInAs and G
at least one ternary compound semiconductor (Ga molar ratio: 0.2 or less) selected from the group consisting of aInP, (4) a quaternary compound semiconductor of AlInAsP, (5) AlGaInP, AlGaInAs, AlGaAsP and GaInAsP At least one quaternary compound semiconductor (Ga molar ratio: 0.2 or less) selected from the group; or (6) A
Pentium compound semiconductor composed of lGaInAsP (Ga molar ratio: 0.
(2) or less).