JP2001156333A - AlGaInP LIGHT EMITTING DIODE - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-luminance AlGaInP LED which has a window layer and the light emitting area of which is expanded by preferentially and uniformly diffusing an operating current in an open light emitting area, by suppressing the leakage of the operating current to the area immediately below a pedestal electrode. SOLUTION: A III-V compound semiconductor junction layer which forms a p-n junction is provided in the area immediately below the pedestal electrode and ohmic electrodes are dispersedly arranged in the open light emitting area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to (Al _M Ga _1-M )
_N In _1- NP (0 ≦ M ≦ 1, 0 <N <1) (hereinafter referred to as AlG
a light emitting diode (AlGaInP-based LED) having a light emitting portion in its light emitting portion.
The present invention relates to a technique for obtaining a high-brightness AlGaInP-based visible light emitting diode having a configuration in which a drive current can be preferentially passed through a light emitting region.

[0002]

2. Description of the Related Art As one of conventional means for obtaining a high-brightness AlGaInP-based LED, (Al _X Ga _{1 -X} ) _0.5 In _0.5 P
Means for providing a window layer made of a conductive transparent oxide material such as indium oxide / tin (ITO) in the upper part of a light emitting portion having a pn junction type double hetero (DH) structure made of No. 11-4020).
However, according to the invention described in Japanese Patent Application Laid-Open No. H11-4020, the I-type pedestal electrode for connection (bonding) is laid.
A metal thin film such as zinc (element symbol: Zn) is provided between the TO transparent electrode layer and the AlGaInP-based LED constituent layer. In this prior art, a metal film of Zn or the like is arranged evenly and almost over the entire surface of the light emitting portion in order to enhance the adhesion between the ITO electrode layer and the III-V compound semiconductor constituent layer. It has become. Accordingly, since the light emitted from the light emitting layer is relentlessly absorbed by the metal film disposed on the metal film disposed immediately below the ITO transparent electrode layer, the high brightness AlGaI
This is an obstacle to obtaining nP-based LEDs.

[0003] (Al _x Ga _{1 -x} ) _0.5 In _0.5 constituting an LED with an oxide layer such as ITO constituting an electrode layer or a window layer
Only by directly joining a III-V group compound semiconductor layer such as P directly forms a relatively high junction barrier,
It is also known that a high forward voltage (so-called Vf) is unnecessarily obtained. Gallium indium nitride (composition formula Ga
_{Z In 1-Z N: 0} ≦ Z ≦ 1) According to recent research reports on system LED, the LED of Vf provided with the junction structure of the group III nitride semiconductor layer and the ITO window layer generally a Vf value (Appl. Phys. Lett., 74).
(26) (1999), p. 3930-3932).
In addition, due to the formation of the junction barrier, the drive current cannot be diffused widely into the light emitting region, and therefore, the high brightness AlGa
There is a problem in obtaining InP-based LEDs.

Conventionally, a transparent oxide layer such as ITO has been
A contact layer is arranged between the III-V compound semiconductor constituent layer constituting D and the ohmic contact between the oxide layer and the III-V compound semiconductor constituent layer is improved. A technique for causing such a phenomenon is disclosed (see Japanese Patent Application Laid-Open No. H11-17220). In the conventional example disclosed in Japanese Patent Application Laid-Open No. 11-17220, GaAs and gallium arsenide phosphide (composition formula:
GaAs _1-Z P _Z : 0 ≦ Z ≦ 1) and the like. However, conventionally, (Al _X Ga _{1 -X} ) _0.5
A contact layer having a smaller forbidden band width than that corresponding to the emission wavelength from the In _0.5 P (0 ≦ X ≦ 1) light emitting layer is laid to cover the surface of the light emitting region (see Japanese Patent Application Laid-Open No.
No. 17220). In this configuration, light emission is absorbed by the contact layer, which hinders obtaining a high-luminance III-V compound semiconductor LED.

[0005]

In a conventional AlGaInP-based LED having a transparent oxide layer as a window layer or the like,
In a region immediately below the pedestal electrode provided on the upper surface of the transparent oxide layer, ITO and LE which form a relatively high junction barrier are used.
The structure is such that the D-group III-V compound semiconductor constituent layer is directly joined (see JP-A-11-17220). However, even though it is a high barrier, it only increases Vf about twice. Therefore, it is not possible to sufficiently prevent the operation current from flowing into the projection area of the pedestal electrode immediately below the pedestal electrode. Light emission in a region immediately below the pedestal electrode (projection region of the pedestal electrode) is shielded by the pedestal electrode, and thus cannot be efficiently extracted to the outside. That is, the operating current flowing into the region immediately below the pedestal electrode is wasted without improving the efficiency of extracting light to the outside.

In order to achieve high brightness, it is possible to avoid wasting operating current to a region immediately below the pedestal electrode and to take out light emission to the outside through the transparent window layer (so-called “outside projection region”). A configuration that can be preferentially dispersed in an open light emitting region) is required. In addition, the configuration allows the operating current to flow preferentially to the open light emitting region, and furthermore, it is not necessary to provide a thin film layer that absorbs light emission as in the related art over the entire open light emitting region. It is necessary to take measures to spread the preferentially supplied operating current without shielding.

An object of the present invention is to provide a high-luminance AlGaInP-based LED by solving the above-mentioned problems in the prior art. A high-brightness AlGaInP-based LED having a configuration that can sufficiently prevent current leakage and a configuration of an ohmic electrode that has a small degree of blocking light emission from the light-emitting layer and that can widely diffuse an operation current into a light-emitting region. It is intended to provide.

[0008]

Means for Solving the Problems The present inventors have intensively studied to solve the above-mentioned problems, and have arrived at the present invention. That is, the present invention provides [1] a group III-V compound semiconductor constituent layer,
In an AlGaInP-based light-emitting diode having a structure in which an ohmic electrode and a pedestal electrode are each in contact with a light-emitting / transmitting window layer, a III-V compound semiconductor layer (hereinafter referred to as III) having a conductivity type opposite to that of a III-V compound semiconductor constituent layer -V
A) is formed in the projection area of the pedestal electrode on the element plane, and the ohmic electrodes are dispersed and arranged in areas other than the projection area.
The outer shape of the 1GaInP-based light emitting diode, [2] III-V compound semiconductor junction layer in the element plane is similar to the bottom shape of the pedestal electrode, and is provided so that the center is coincident. AlGaI according to [1]
The outer shape of the nP-based light emitting diode and the [3] III-V compound semiconductor bonding layer in the element plane is 0.5 times or more and 1.5 times or less the bottom area of the pedestal electrode. ] Or [2], wherein the [4] light emitting layer is made of (Al _x Ga _{1 -x} ) _0.5 In.
AlGaIn according to any one of [1] to [3], wherein the AlGaIn is formed from _0.5 P (0 ≦ X ≦ 1).
P-based light emitting diode, [5] III-V compound semiconductor junction layer is (Al _Y Ga _{1 -Y} ) _0.5 In _0.5 P (X ≦ Y ≦
The present invention relates to the AlGaInP-based light-emitting diode according to [4], which is configured from 1).

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS AlGaInP LED of the present invention
Has a basic structure in which a III-V compound semiconductor constituent layer, an ohmic electrode, and a pedestal electrode are each in contact with a light-emitting and transmitting window layer. AlGaInP-based LED according to the present invention
1 is exemplified in FIG. Referring to FIG. 1, the LED 10 of the first embodiment according to the first embodiment of the present invention mainly includes a conductive single crystal substrate 1.
And n-type or p-type clad layers 104 and 106 made of, for example, (Al _x Ga _{1 -x} ) _0.5 In _0.5 P, which are stacked on the surface of the semiconductor device 01 by an epitaxial growth method.
A light emitting section 10a formed by a hetero junction with a light emitting layer 105 made of (Al _x Ga ₁ -x) _0.5 In _0.5 P
And a window layer 108 made of a conductive transparent oxide layer covered on the upper cladding layer 106 constituting the light emitting portion 10a. Lower cladding layer 104
Bragg reflection (DBR)
There is no problem even if a configuration in which 103 is inserted is used. Window layer 1
A pedestal electrode 109 for supplying an LED driving current is provided at the center of the upper surface of the substrate 08. In addition, the LED 1 of the present invention
0 is characterized by a III-V compound semiconductor bonding layer having a conductivity type opposite to that of the upper cladding layer 106 between, for example, the AlGaInP upper cladding layer 106 on which the transparent oxide layer forming the window layer 108 is deposited. 107 is arranged.

III-V compound semiconductor bonding layer 107
As shown in the sectional structural view of the LED 10 illustrated in FIG. 1, for example, the LED is provided only on the projection region 109 a of the pedestal electrode 109 on the surface of the upper cladding layer 106. For example,
On the p-type upper cladding layer 106, an n-type III-V
A group III compound semiconductor bonding layer 107 is provided. n-type III-
A p-type group III-V compound semiconductor junction layer is provided on the group V compound semiconductor constituent layer. For example, the upper cladding layer 1
A pn junction is formed by bonding a bonding layer of the conductivity type opposite to the bonding layer to the III-V compound semiconductor constituent layer constituting the LED 10 such as 06. Pedestal electrode 109
By forming a pn junction in the projection region 109a of the pn junction that obstructs current flow, short-circuit leakage of the operating current supplied from the pedestal electrode 109 to the light emitting unit 10a can be avoided. In other words, the effect that the operating current is preferentially flown into the open light emitting area 106a around the projection area 109a of the pedestal electrode 109 is improved. That is, waste of the operating current in the light-shielding region is suppressed, and the open light-emitting region 1 from which light can be extracted to the outside can be obtained.
06a can be preferentially allocated, which is advantageous for achieving higher luminance.

III-V compound semiconductor bonding layer 107
Can be formed on the upper cladding layer 106 by an epitaxial growth means such as a metal organic chemical decomposition (MOCVD) method or a molecular beam epitaxial (MBE) method. By patterning the formed III-V compound semiconductor bonding layer 107 using a known photographic technique and removing unnecessary portions, the III-V compound semiconductor bonding layer is formed only in the projection region 109a of the pedestal electrode 109. Layer 107 can be left. It is desirable that the layer thickness of the III-V compound semiconductor bonding layer 107 does not exceed the layer thickness of the window layer 108 made of a transparent oxide. I
The layer thickness of the II-V compound semiconductor bonding layer 107 is changed to the window layer 10.
If it is larger than that of 8, the step between the bonding layer 107 and the layer to be deposited is increased, and it becomes difficult to cover the periphery of the bonding layer 107 without voids. Since it is desired to set the thickness of the window layer 108 to a thickness that results in the maximum transmittance for the light emitted from the light emitting layer 105,
Therefore, it is desirable that the thickness of the bonding layer 107 be equal to or less than the thickness of the window layer 108 that provides the maximum transmittance for the emission wavelength.

III-V compound semiconductor bonding layer 107
In addition, the leakage of the operating current to the area immediately below the pedestal electrode 109 is reduced.
The effect of blocking by forming a pn junction with the lower layer is better.
In order to exhibit the efficiency more efficiently, a group III-V compound
The carrier concentration of the conductor bonding layer 107 is, for example,
About 1/10 or more of the carrier concentration of the layer to be deposited such as
It is desirable that The layer to be deposited has, for example, a carrier concentration
Is 1 × 10¹⁸cm^-3N-type III-V compound semiconductor
If it is a body layer, the III-V compound semiconductor bonding layer 107
Is p-type and its carrier concentration is 1 × 10¹⁷cm^-3Less than
It is preferably above. Furthermore, 1 × 10¹⁷cm^-3that's all
At 1 × 10¹⁹cm^-3It is preferred that: III-
The carrier concentration of the group V compound semiconductor bonding layer 107 is 1 ×
10¹⁹cm ^-3If it exceeds, the crystallinity is inferior.
This is not preferable because it may cause a breakdown voltage failure.

III-V compound semiconductor bonding layer 107
Achieves good lattice matching with the underlying layer II
It can be preferably composed of an IV group compound semiconductor layer. Good lattice matching means that the degree of lattice mismatch given by the value obtained by dividing the difference in lattice constant by the lattice constant of the layer to be deposited is approximately 5%.
% Or less. For example, (Al _P Ga _1-P ) _{0.
There is an example in which} the III-V compound semiconductor bonding layer 107 is composed of aluminum / gallium arsenide (composition formula: Al _C Ga _1-C As: 0 ≦ C ≦ 1) for the layer to be deposited made of ₅ In _0.5 P. .

After providing the III-V compound semiconductor bonding layer 107 which can prevent the leakage of the operating current to the region immediately below the pedestal electrode 109 as described above, the present invention further provides a plurality of ohmic contacts in the open light emitting region 106a. The electrodes 110 are provided in a dispersed manner. The open light emitting area 106a is the pedestal electrode 1
09 refers to a region other than the region where the laying is provided, from which light can be extracted to the outside (other than the projection region of the pedestal electrode on the element plane). In the LED 10 illustrated in FIG. 1, ohmic electrodes 110 each having a circular planar shape are arranged in the open light emitting region 106a. The planar shape of the ohmic electrode 110 may be elliptical, square, or polygonal. There is no limitation on the number of the ohmic electrodes 110 to be dispersed. The ohmic electrode 110 can be made of, for example, a gold (Au) / germanium (Ge) alloy, a gold (Au) / zinc (Zn) alloy, or the like. The pn junction with the III-V compound semiconductor junction layer suppresses the leakage of the operating current to the region directly below the pedestal electrode 109, and creates a situation where the operating current can be preferentially distributed to the open light emitting region 106a. By dispersing and providing the ohmic electrodes 110 in the open light emitting region 106a, the operating current can be spread over a wide range of the open region 106a through each ohmic electrode 110.

According to a second embodiment of the present invention, a III-V compound semiconductor bonding layer 1 is provided.
07 is made of a crystal layer having a similar relationship to the outer shape of the pedestal electrode 109 in the element plane. That is, for the circular pedestal electrode, the group III-V compound semiconductor bonding layer 107 having a circular planar shape is disposed. A polygonal high-resistance III-V compound semiconductor layer is provided for a polygonal pedestal electrode. For the square base electrode, a square group III-V compound semiconductor bonding layer is provided. In particular, it is desirable that the planar shape of the III-V compound semiconductor bonding layer 107 be similar to the shape of the bottom surface of the pedestal electrode 109 that contacts the window layer 108.

Further, the III-V compound semiconductor bonding layer 1
Reference numeral 07 is provided such that the center M of the planar shape matches the center point C of the planar shape of the pedestal electrode 109. By making the planar shape of the III-V compound semiconductor bonding layer 107 similar to the bottom shape of the pedestal electrode 109 and arranging the center points M and C so as to match each other, the overall bottom surface of the pedestal electrode 109 is formed. It is possible to efficiently prevent the short-circuiting operation current from flowing to the light-emitting portion 10a in the appropriate region. For example, once on the upper cladding layer 106, the III-V compound semiconductor bonding layer 10
7, for example, metalorganic thermal decomposition vapor deposition (MOCVD)
After stacking by the method, the center is matched with the center of the projection region 109a of the pedestal electrode 109 by a patterning technique using a general photolithography technique, and the III-V
It is preferable to leave the group III compound semiconductor bonding layer 107. By aligning the center points M and C of the planar shapes of the III-V compound semiconductor bonding layer 107 and the pedestal electrode 109, the operating current is caused to drift to the light emitting portion 10a due to the "deviation" of the planar shape center. Can be prevented. If the center points C and M do not match, the operating current supplied from the pedestal electrode 109 will be II due to the "shift" of the center points C and M in the projection area 109a of the pedestal electrode 109.
The inconvenience of short-circuiting to the light emitting portion 10a through the uncovered region of the IV compound semiconductor bonding layer 107 occurs.

III- with respect to the bottom area of the pedestal electrode 109
There is a suitable range for the ratio of the area of the outer shape on the element plane of the group V compound semiconductor bonding layer 107. Pedestal electrode 109
III-V compound semiconductor bonding layer 10 with respect to the bottom area of
If the area occupied by 7 is extremely small, a short-circuit current to the light emitting unit 10a increases. On the other hand, if the area of the III-V compound semiconductor bonding layer 107 is extremely large, the open light-emitting area decreases, and it becomes difficult to increase the luminance of light emission. Therefore, in the third embodiment according to the third aspect of the present invention,
The area of the outer shape of the II-V compound semiconductor bonding layer 107 in the element plane is approximately 0.1 mm as compared with the bottom area of the pedestal area.
It is desirable to set it to 5 times or more and 3 times or less. Furthermore, 0.
It is preferable that the ratio be 7 times or more and 1.2 times or less.

In the fourth and fifth embodiments according to the fourth and fifth aspects of the present invention, the light emitting layer 105 is made of G
(Al _x Ga _1-x ) _0.5 I that is easily lattice-matched to the aAs substrate
An n _0.5 P (0 ≦ X ≦ 1) layer is formed, and the III-V compound semiconductor junction bonding layer 107 forms the (Al _x Ga _1-x ) _0.5 In _0.5 P (0 ≦ X ≦ 1) The layer is composed of (Al _Y Ga _1-Y ) _0.5 In _0.5 P (that is, X ≦ Y ≦ 1) having an aluminum composition ratio (= Y) which is equal to or more than the aluminum (Al) composition ratio (= X) of the layer. It is characterized by. (Al
_Y Ga _1-Y ) _0.5 In _0.5 P is the aluminum composition ratio (= Y)
In addition to achieving good lattice matching with (Al _X Ga _{1 -x} ) _0.5 In _0.5 P, the band gap increases with an increase in the aluminum composition ratio (= Y). The aluminum composition ratio (= Y) was changed to
(= X) or more (Al _Y Ga _{1 -Y} ) _0.5 In _0.5
P can transmit light. Therefore, from the band gap of (Al _Y Ga _{1 -Y} ) _0.5 In _0.5 P having a band gap equal to or larger than that of the light emitting layer 105, III- which exhibits a function as a current blocking layer while transmitting light emission.
The group V compound semiconductor bonding layer 107 can be formed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail by taking as an example the case of forming an AlGaInP-based LED having a III-V compound semiconductor junction layer. FIG. 2 shows A according to this embodiment.
1 shows a schematic plan view of an lGaInP-based LED 20. FIG. Also,
FIG. 3 is a schematic cross-sectional view of the LED 20 shown in FIG. 2 along the broken line AA ′.

The LED 20 is made of zinc (Z) having a diameter of about 50 mm.
n) Doped p-type (001) -GaAs single crystal circular substrate 2
01, a Zn-doped p-type GaAs buffer layer 202, which is sequentially stacked, and a Zn-doped p-type Al _0.40 G
a Bragg reflection (DB) having a periodic structure in which ten a _0.60 As layers and ten p-type Al _0.95 Ga _0.05 As layers are alternately stacked.
R) layer 203, Zn-doped p-type (Al _0.7 Ga _0.3 ) _0.5
A lower cladding layer 204 made of In _0.5 P, a light emitting layer 205 made of an undoped n-type (Al _0.2 Ga _0.8 ) _0.5 In _0.5 P mixed crystal, and a Si-doped n-type (Al _0.7 Ga _0.3 ) _0.5 I
n _0.5 P upper cladding layer 206, Zn-doped p
III-V consisting of (Al _0.3 Ga _0.7 ) _0.5 In _0.5 P
The epitaxial laminated structure (wafer) 2A composed of the group III compound semiconductor bonding layer 207 was formed as a base material.

Each constituent layer 202 constituting the laminated structure 2A
To 207 are trimethyl aluminum ((CH ₃ ) ₃ A)
l), trimethylgallium ((CH ₃ ) ₃ Ga) and trimethyl indium ((CH ₃ ) ₃ In) were formed by a low-pressure MOCVD method using a group III constituent element as a raw material. Diethyl zinc ((C ₂ H ₅ )) is used as a zinc (Zn) doping source.
₂ Zn) was used. Disilane (Si ₂ H ₆ ) was used as a silicon (Si) dopant source. Each constituent layer 202-2
The film forming temperature of 07 was unified to 730 ° C. The carrier concentration of the buffer layer 202 was about 5 × 10 ¹⁸ cm ⁻³ , and the layer thickness was about 1 μm. P-type Al _0.40 Ga forming the DBR layer 203
The thickness of each of the _0.60 As layer and the p-type Al _0.95 Ga _0.05 As layer was about 40 nm. Each carrier concentration is about 1 × 1
0 ¹⁸ cm ⁻³ . The lower cladding layer 204 has a carrier concentration of about 3 × 10 ¹⁸ cm ⁻³ and a thickness of about 1.5 μm.
And The thickness of the light emitting layer 205 was about 750 nm, and the carrier concentration was about 5 × 10 ¹⁶ cm ⁻³ . The carrier concentration of the upper cladding layer 206 was about 1 × 10 ¹⁸ cm ^−3, and the layer thickness was about 5 μm. Zn-doped p-type (Al _0.7
Ga _{0 .3) 0.5} In _0.5 the carrier concentration of the P layer 207 is about 5
× 10 ¹⁸ cm ^-3 and a layer thickness of about 100 nm.

Next, using a known photolithography technique, only the projection region 209a corresponding to the region where the pedestal electrode 209 is to be formed on the surface of the window layer 208 is formed in a circular shape with a Zn-doped p-type having a diameter of 110 μm. Shape (Al _0.7 G
a _0.3 ) _0.5 In _0.5 P layer 207 was left. The center point C of the projection region 209a of the pedestal electrode 209 and the lower layer III
The center point M of the −V group compound semiconductor bonding layer 207 was matched. After that, the Zn-doped p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P exposed in a region other than the projection region 209a
Once on the entire surface of the layer 207, gold (Au 88% by weight)
A germanium (Ge 12 wt%) alloy film was deposited by a common vacuum deposition method. Alloy film thickness is about 100nm
And Next, patterning is performed again using photolithography technology, and this time, ohmic electrodes 210 are formed.
The above Au / Ge alloy film was left only in the region where was formed. The region where the alloy film was left was a square having a side of 20 μm. After that, argon (element symbol: Ar)
An alloying heat treatment was performed at 420 ° C. for 10 minutes in an air stream. The ohmic electrodes 210 are located on the surface of the open light-emitting region 206a of the upper cladding layer 206 at a total of eight locations.
It was formed by dispersing at an equal distance of 0 μm.

Next, the ohmic electrode 210, the surface of the upper cladding layer 206 other than the dispersed ohmic electrode 210, and the group III-V compound semiconductor bonding layer 207 left only in the projection region 209a of the pedestal electrode 209 are removed. An indium tin oxide (ITO) film was applied as a window layer 208 for transmitting light emission to the outside so as to cover the film. The ITO film was applied by a general magnetron sputtering method. The specific resistance of the ITO layer is about 5 × 10 ⁻⁴ Ω · cm,
The layer thickness was about 600 nm. Next, after a general organic photoresist material was applied to the entire surface of the window layer 208, a region where the pedestal electrode 209 was to be provided was patterned using a known photolithography technique. Thereafter, a gold (Au) film was deposited on the entire surface by a vacuum deposition method while the patterned resist material was left. Gold (A
u) The thickness of the film was about 700 nm. After that, according to a well-known lift-off means, the Au film was left only in the region where the pedestal electrode 209 was to be formed while the resist material was peeled off. From this, the diameter is about 1
A circular pedestal electrode 209 having a thickness of 10 μm was formed. That is, the surface area of the group III-V compound semiconductor bonding layer 207 was the same.

After a p-type ohmic electrode 211 made of a gold-zinc (Au-Zn) alloy is formed on the back surface of the p-type GaAs single crystal substrate 201, the laminated structure (wafer) 2A is cut by a usual scribing method. And subdivide it individually,
The LED 20 had a side length of 260 μm. p
When a current was passed between the ohmic electrode 211 and the pedestal electrode 209 in the forward direction, red-orange light having a wavelength of about 620 nm was emitted through the open light emitting region 206a. The half width of the light emission spectrum was about 20 nm, and the light emission was excellent in monochromaticity. The forward voltage (Vf: ＠ 20 mA) when a current of 20 milliamperes (mA) flows is about 2.1 volts (V), reflecting the good ohmic characteristics of the distributed ohmic electrode 210. It became. Also,
Due to the effect of distributing and arranging the ohmic electrodes 210, light emission is also observed in the region of the peripheral edge 20b of the chip 20, and the light emission intensity measured simply with the visibility corrected is about 70 mm. Candela (mcd). Further, in the LED 20 of the present embodiment, even from the viewpoint of the near-field light emission pattern, the distribution of the light emission intensity on the open light emission surface 206a was uniform due to the effect of the uniform distribution of the operation current by the ohmic electrode 210. .

[0025]

According to the first aspect of the present invention, the ohmic electrodes are dispersedly provided in the open light-emitting area outside the projection area of the pedestal electrode, and the p-type is formed in the area immediately below the pedestal electrode.
Since the structure is such that the III-V compound semiconductor junction layer forming the n-junction is provided, the short-circuit leakage of the operating current to the light emitting portion immediately below the pedestal electrode is suppressed, and the operation is preferentially supplied to the open light emitting region. Since the current can be widely distributed in the same region, an AlGaInP-based light-emitting diode having a high luminance and an enlarged light-emitting region can be provided.

According to the second aspect of the present invention, a III-V compound semiconductor bonding layer similar in shape to the pedestal electrode is provided so as to match the center of the planar shape of the pedestal electrode. Therefore, particularly, the leakage of the operating current to the region immediately below the pedestal electrode can be efficiently prevented, and the operating current can be preferentially distributed to the open light emitting region, so that a high-luminance AlGaInP-based light emitting diode can be provided.

According to the third aspect of the present invention, the surface area of the III-V compound semiconductor bonding layer is defined with respect to the surface area of the pedestal electrode.
The effect of efficiently preventing the operating current from leaking to the region immediately below the pedestal electrode is improved, and a high-luminance AlGaInP-based light-emitting diode can be provided.

According to the fourth and fifth aspects of the present invention, the substrate is lattice-matched (Al _x Ga _{1 -x} ).
_A light emitting layer composed of _0.5 In _0.5 P, and a (Al _Y Ga _1-Y ) _0.5 In _0.5 P to III having a band gap greater than or equal to the light emitting layer
Since a -V compound semiconductor junction layer is to be formed,
Since light emission can be transmitted while suppressing leakage of an operating current directly below the pedestal electrode, a high-luminance AlGaInP-based light-emitting diode can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an AlGaInP-based LED according to the present invention.

FIG. 2 is a schematic plan view of the AlGaInP-based LED described in Example 1.

FIG. 3 is a schematic cross-sectional view of the LED of FIG. 2 along a broken line AA ′.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 AlGaInP-based LED 10 a pn junction type double hetero junction light emitting unit 101 single crystal substrate 102 buffer layer 103 Bragg reflection layer 104 lower cladding layer 105 light emitting layer 106 upper cladding layer 106 a open light emitting region 107 III-V compound semiconductor bonding layer 108 window Layer 109 Pedestal electrode 109a Projection area of pedestal electrode 110 Ohmic electrode 111 Ohmic electrode on backside of substrate C Center point of pedestal electrode M Center point of MIII-V compound semiconductor bonding layer 2A Stacked structure 20 AlGaInP LED 20b Outer edge of LED chip 201 p-type GaAs single crystal substrate 202 p-type GaAs buffer layer 203 Bragg reflection layer 204 AlGaInP-based lower clad layer 205 AlGaInP-based light-emitting layer 206 AlGaInP-based upper clad layer 206a open light emission Projection region 210 ohmic electrode 211 p-type ohmic electrode band 207 III-V group compound semiconductor junction layer 208 conductive transparent oxide window layer 209 the base electrode 209a seat electrode

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takashi Udagawa 1505 Shimokagemori, Chichibu-shi, Saitama F-term (reference) 5F041 AA03 CA04 CA34 CA36 CA65 CA73 CA74 CA83 CA85 CA88 CA93 CA98 CB15

Claims (5)

[Claims] 1. An AlGaInP-based light-emitting diode having a structure in which a III-V compound semiconductor constituent layer, an ohmic electrode, and a pedestal electrode are each in contact with a light-emitting / transmitting window layer, the opposite of the III-V compound semiconductor constituent layer. A conductive type III-V compound semiconductor layer (hereinafter referred to as a III-V compound semiconductor junction layer) is formed in a projection area of a pedestal electrode on an element plane, and ohmic electrodes are dispersed and arranged in areas other than the projection area. AlGa characterized in that
InP-based light emitting diode. 2. The semiconductor device according to claim 1, wherein the outer shape of the III-V compound semiconductor bonding layer in the element plane is similar to the bottom shape of the pedestal electrode, and is provided so as to coincide with the center. 2. An AlGaInP-based light-emitting diode according to item 1. 3. The device according to claim 1, wherein the outer shape of the III-V compound semiconductor bonding layer in the element plane is 0.5 times or more and 1.5 times or less the bottom area of the pedestal electrode. 2. An AlGaInP-based light-emitting diode according to item 1. 4. A light-emitting layer comprising: (Al _X Ga _{1 -X} ) _0.5 In _0.5 P
The AlGaInP-based light-emitting diode according to claim 1, wherein the AlGaInP-based light-emitting diode is formed from (0 ≦ X ≦ 1). 5. The method according to claim 1, wherein the group III-V compound semiconductor bonding layer comprises (A)
5. The AlGaIn according to claim 4, wherein the AlGaIn is composed of (L _Y Ga _1-Y ) _0.5 In _0.5 P (X ≦ Y ≦ 1).
P-based light emitting diode.