JP2004193338A - Nitride based compound semiconductor light emitting element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nitride based compound semiconductor element excellent in outputting the light. <P>SOLUTION: In the nitride based compound semiconductor light emitting element, an electrode for a p-type, a p-type semiconductor layer, a light emitting layer, an n-type semiconductor layer and an electrode for an n-type are formed sequentially on a base substrate. The electrode side for an n-type is the main light output surface. The element is characterized by that a current inhibition layer is formed in a part between the p-type semiconductor layer and the electrode for a p-type. The manufacturing method of the element contains a process for forming sequentially the n-type semiconductor layer, a light emitting layer, and the p-type semiconductor layer on the substrate; a process for forming the electrode for a p-type after the current inhibition layer is formed in a part on the p-type semiconductor layer; a process for forming the seating substrate on the electrode for a p-type; and a process for eliminating a part or the whole oh the substrate, and exposing a part or the whole of the n-type semiconductor layer. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor light emitting device using a nitride-based compound semiconductor (In _x Al _Y Ga _{1 -XYN} : 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) and a method for manufacturing the same.
[0002]
[Prior art]
A nitride-based compound semiconductor light emitting device containing nitrogen such as gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN), and a mixed crystal thereof mainly emits light of a short wavelength such as blue or blue-green. It is used as a light emitting element to bring about. Various attempts have been made to increase the light emission intensity of such a nitride compound semiconductor light emitting device. For example, there is a technique in which a current blocking layer and a conductive thin film electrode are interposed between a pedestal electrode and a contact layer in order to increase the ratio of an operating current that contributes to light emission (see Patent Document 1).
[0003]
In this light-emitting device, as shown in FIG. 7, an n-type GaN lower cladding layer 102, a light-emitting layer 103, a p-type upper cladding layer 104, and a p-type contact layer 105 are formed on a sapphire substrate 101, and then the current is blocked. A layer 108 is formed, and a conductive thin film electrode 109 and a pad electrode 110 are formed thereon. Light emission due to an operating current directly injected from the pad electrode 110 into the light emitting layer 103 is blocked by the pad electrode 110 and does not contribute to light extraction. For this reason, by providing the current blocking layer 108 to block conduction of the operating current from the pad electrode 110 to the light emitting layer 103, unnecessary light emission that does not contribute to light extraction is reduced. Further, the light-transmitting conductive thin film electrode 109 made of a metal or the like can diffuse an operating current over a wide range of the light-emitting layer 103 and increase the proportion of the operating current that contributes to light emission.
[0004]
[Patent Document 1]
JP-A-9-129921 (pages 2 to 6)
[0005]
[Problems to be solved by the invention]
However, in this technique, although no current flows directly under the opaque pad electrode, no light is emitted.However, of the light emitted from other portions, light emitted below the light emitting layer is emitted on the bottom surface of the substrate. When the light is reflected and returns to the pad electrode again, light is absorbed by the pad electrode, leading to a decrease in light output. Further, the conductive thin-film electrode provided on the p-type electrode side is a translucent film made of a metal or the like, though it is translucent, and therefore has a large light absorption, leading to a decrease in light output.
[0006]
An object of the present invention is to provide a nitride-based compound semiconductor light emitting device having good light extraction efficiency.
[0007]
[Means for Solving the Problems]
In the nitride-based compound semiconductor light emitting device of the present invention, a p-type electrode, a p-type semiconductor layer, a light-emitting layer, an n-type semiconductor layer, and an n-type electrode are sequentially formed on a pedestal substrate. In a light emitting element in which the main electrode is the main light extraction surface, a current blocking layer is provided in a part between the p-type semiconductor layer and the p-type electrode.
[0008]
Further, the method for manufacturing a nitride-based compound semiconductor light emitting device of the present invention includes a step of sequentially forming an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer on a substrate; Forming a current blocking layer in the portion, forming a p-type electrode, forming a pedestal substrate on the p-type electrode, removing part or all of the substrate, and forming an n-type semiconductor layer. Exposing a part or the whole thereof.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
(Nitride compound semiconductor light emitting device)
In the nitride-based compound semiconductor light emitting device of the present invention, the n-type electrode side is a main light extraction surface, and a current blocking layer is provided in a part between the p-type semiconductor layer and the p-type electrode. Features. By using the electrode for n-type as the light extraction surface, it is not necessary to use an electrode made of a translucent metal thin film, so that there is little decrease in light output, and by providing a current blocking layer, unnecessary light emission is eliminated. The light extraction efficiency can be greatly increased.
[0010]
A part of the n-type electrode functions as a bonding pad electrode, or a bonding pad electrode is formed on the n-type electrode, and the bonding pad electrode is opaque to light emitted from the light emitting layer. It is preferable that the electrode is formed so as to be located inside the region where the current blocking layer is formed when viewed from above the n-type electrode. By forming the opaque bonding pad electrode so as to fit inside the region where the current blocking layer is formed, no light is emitted immediately below the bonding pad electrode, so that there is no unnecessary light emission and light extraction efficiency can be increased. It is also preferable that the n-type electrode also functions as a bonding pad electrode, and in this case, the bonding electrode is opaque. Therefore, a part of the n-type electrode is used as the bonding pad electrode. Need to work.
[0011]
The n-type electrode is preferably a transparent conductive film. By using a transparent conductive film as the n-type electrode, current can be injected into the n-type layer without blocking light from the light-emitting layer. The pedestal substrate is preferably opaque to light emitted from the light-emitting layer, and the p-type electrode is formed of a highly reflective layer having a reflectance of 60% or more at the wavelength of light emitted from the light-emitting layer. And the reflectance is more preferably 80% or more. By providing an opaque pedestal substrate on the p-type semiconductor layer side and providing a highly reflective layer between the p-type semiconductor layer and the opaque pedestal substrate, light emitted from the light emitting layer and emitted to the pedestal substrate side Is reflected by the high reflection layer and emitted to the upper part, so that the light extraction efficiency can be improved. Therefore, the driving voltage can be reduced, and there is no peeling even after long-term use, and the reliability is high.
[0012]
The current blocking layer preferably has at least one of a high-resistance layer having a specific resistance of 1 Ωcm or more, an n-type semiconductor layer, and a Schottky junction layer, from the viewpoint of sufficiently blocking a current. The high reflection layer in the p-type electrode preferably contains Ag from the viewpoint that an electrode having a high reflectance can be obtained. On the other hand, the pedestal substrate is preferably made of a metal, an alloy, or Si because an inexpensive element can be manufactured. For example, metals such as Ni, Al, and Cu, zinc alloys, and aluminum alloys such as Al-Mg and Al-Mg-Si are preferable.
[0013]
(Method of manufacturing nitride compound semiconductor light emitting device)
The method for manufacturing a nitride-based compound semiconductor light-emitting device according to the present invention includes a step of sequentially forming an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer on a substrate; After forming the current blocking layer, forming a p-type electrode, forming a pedestal substrate on the p-type electrode, removing a part or all of the substrate, and forming a part of the n-type semiconductor layer. Or exposing the whole. According to this method, a nitride-based compound semiconductor light-emitting device having no light emission and good light extraction efficiency can be manufactured.
[0014]
From the viewpoint of obtaining a good ohmic junction between the p-type contact layer and the p-type electrode and increasing the adhesion, it is preferable to perform a heat treatment at 300 ° C. to 700 ° C. after forming the p-type electrode. From this viewpoint, it is more preferable to perform the heat treatment at 500 ° C. to 600 ° C. for 1 minute to 5 minutes. Further, in the manufacturing method of the present invention, the substrate on which the n-type semiconductor layer, the light-emitting layer, the p-type semiconductor layer, and the like are sequentially formed is removed after the formation of the pedestal substrate, but the etching includes hydrofluoric acid and nitric acid. A substrate made of Si is preferable because it can be dissolved in a liquid and easily removed. On the other hand, the etching solution containing hydrofluoric acid and nitric acid shows strong selectivity to a nitride-based compound semiconductor such as AlN, and exposes a buffer layer such as AlN having a flat surface by etching. be able to. In the etching, an n-type semiconductor layer made of GaN or the like can function as an etching stop layer.
[0015]
The pedestal substrate is preferably formed by a plating method in that a conductive pedestal substrate can be easily obtained. The pedestal substrate is a Si substrate, and it is preferable to form such a substrate on the p-type electrode by thermocompression bonding, since sufficient bonding strength can be obtained. In the thermocompression bonding, AuSn, AuGe, or the like is preferably used as the metal to be bonded, and it is preferable to perform bonding at a temperature lower than the eutectic point of the metal to be bonded.
[0016]
【Example】
Example 1
FIG. 1 is a cross-sectional view of a light-emitting element in which a pedestal substrate is a thick film Ni. FIG. 1A is a cross-sectional view in the middle of manufacturing, and FIG. It is sectional drawing. A buffer layer 11 made of Si-doped AlN and an n-type semiconductor layer 12 made of Si-doped GaN are formed on a Si substrate 10, and a multi-quantum structure composed of a barrier layer made of GaN and a well layer made of InGaN is formed thereon. A light emitting layer 13 of a well was formed. A p-type cladding layer 14 made of p-type AlGaN was formed on the light emitting layer 13, and a p-type contact layer 15 made of p-type GaN was formed on the p-type cladding layer 14. Next, an SiO ₂ layer having a thickness of 10 nm was formed as a current blocking layer 16 on the surface of the p-type contact layer 15 by a lift-off method.
[0017]
On the surface of the p-type contact layer 15 and on the current blocking layer 16, a 1.5-nm-thick Pd adhesion layer 17a and a 150-nm-thick Ag high-reflection layer 17b are deposited as p-type electrodes 17 by vacuum evaporation. At 500 ° C. for 3 minutes to form an alloy with the p-type contact layer 15. By this heat treatment, a good ohmic junction between the p-type contact layer 15 and the p-type electrode 17 was obtained, and the adhesion was increased. Next, 300 nm thick Au is deposited on the p-type electrode 17 as a plating base layer 18, and a 100 μm thick thick film Ni is formed on the plating base layer 18 as a pedestal substrate 19 by an electrolytic plating method. Formed. In the state where the plating base layer 18 is formed, the region where the current blocking layer 16 is formed has a convex shape. However, Ni is formed by electrolytic plating so that the convex portion becomes gentle. In the state formed with 100 μm, it was almost flat.
[0018]
Next, in order to remove the Si substrate 10, the side surfaces of the pedestal substrate 19 and the wafer are covered with electron wax, and etching is performed by mixing 70% hydrofluoric acid, 60% nitric acid and glacial acetic acid at a ratio of 5: 2: 2. The liquid was used to dissolve and remove the Si substrate 10, exposing the surface of the buffer layer 11 made of Si-doped AlN. By using such an etchant, the etching rate was low for a nitride-based compound semiconductor such as AlN, selective etching was performed favorably, and the surface of the exposed AlN buffer layer became flat. The electron wax was removed with an organic solvent such as acetone. Next, an n-type electrode 20 made of ITO having a thickness of 200 nm was formed on the buffer layer 11 made of Si-doped AlN by sputtering. By heating at 250 ° C. during sputtering, a good ohmic junction was obtained between the buffer layer 11 made of Si-doped AlN and the n-type electrode 20.
[0019]
Next, a Mo adhesion layer 21a having a thickness of 10 nm and an Au bonding layer 21b having a thickness of 500 nm were formed on the n-type electrode 20 as the pad electrodes 21 for bonding. At this time, the pad electrode 21 for bonding was formed by a lift-off method using ordinary photolithography so that the pad electrode 21 for bonding was located inside the current blocking layer 16 when viewed from above the n-type electrode 20. Next, in order to remove ITO in a portion to be diced, portions other than the dicing line were covered with a photoresist, and the ITO was removed by wet etching with an iron chloride-based etchant.
[0020]
After that, portions other than the dicing lines were covered with a photoresist in order to remove a portion of the semiconductor layer to be diced by dry etching. As a dry etching method, a portion not covered with the photoresist was etched until the p-type electrode 17 was exposed. Finally, the wafer was divided into 300 μm pieces by dicing. FIG. 2 is a plan view of the light-emitting device manufactured as described above, as viewed from above the n-type electrode. In FIG. 2, the n-type electrode 220 is formed on the p-type electrode 217, and the bonding pad electrode 221 is formed to fit inside the region where the current blocking layer 216 is formed.
[0021]
Since the manufactured light emitting element does not emit light immediately below the bonding pad electrode made of a thick metal that does not transmit light, useless light emission can be eliminated. In addition, since the p-type electrode has a high reflectance with respect to light emitted from the light emitting layer, light extraction efficiency was good. For this reason, peeling did not occur even in a long drive test at a low drive voltage, and the reliability was improved. In this embodiment, AlN is doped with Si, but non-doped AlN may be used for the buffer layer. In this case, after removing the Si substrate, part or all of the AlN is removed by dry etching to expose the Si-doped GaN layer. In this case, an n-type electrode may be formed.
[0022]
Further, in the present embodiment, the thick film Ni of the pedestal substrate is formed by the electrolytic plating method. However, an electroless plating method may be used, and any material other than Ni may be used as long as it can be formed by the plating method. Are preferred. Further, in this embodiment, ITO is formed on the entire surface of the n-type semiconductor layer as the n-type electrode, but the pad electrode may be formed without forming the ITO. In this case, the pad electrode is preferably formed by forming Hf to a thickness of 5 nm and then forming Al to a thickness of 150 nm.
[0023]
Example 2
FIG. 3 is a plan view when an SiO ₂ mask 331 for selectively growing a crystal is provided on a Si substrate 330. The mask 331 has a thickness of 300 nm, and the openings are 200 μm square and arranged at a pitch of 300 μm. FIGS. 4A and 4B are cross-sectional views of a light emitting device formed using a Si substrate 30 in order to manufacture a light emitting device in which the pedestal substrate 40 is a thick film Ni. FIG. (B) is a cross-sectional view before a substrate is divided, and (c) is a cross-sectional view at a completed stage.
[0024]
As shown in FIG. 4A, when the nitride-based compound semiconductor is grown on the Si substrate 30, the nitride-based compound semiconductor is formed only in the region where the mask 31 does not exist, that is, only in the opening where the Si surface is exposed. Grew selectively. In this embodiment, a buffer layer 32 made of AlN and an n-type semiconductor layer 33 made of silicon-doped GaN are formed on an Si substrate 30 on which a selective growth mask 31 is partially formed, and GaN is formed thereon. A multiple quantum well light emitting layer 34 composed of a barrier layer and a well layer made of InGaN was formed. A p-type cladding layer 35 made of p-type AlGaN was formed on the light emitting layer 34, and a p-type contact layer 36 made of p-type GaN was formed on the p-type cladding layer 35. Next, an SiO ₂ layer having a thickness of 100 nm was formed as a current blocking layer 37 on the surface of the p-type contact layer 36 by a lift-off method.
[0025]
On the surface of the p-type contact layer 36 and the current blocking layer 37, a 1.5-nm-thick Pd adhesion layer 38a and a 150-nm-thick Ag high-reflection layer 38b are formed by vapor deposition as p-type electrodes. By performing a heat treatment at 500 ° C. for 3 minutes, alloying with the p-type contact layer 36 was performed. By this heat treatment, a good ohmic junction between the p-type contact layer 36 and the p-type electrode was obtained, and the adhesion was increased. Next, an Au layer having a thickness of 300 nm was deposited as a plating base layer 39 on the p-type electrode. Next, a thick film Ni having a thickness of 100 μm was formed as a pedestal substrate 40 on the plating base layer 39 by an electrolytic plating method. FIG. 4A shows a state at this stage.
[0026]
Thereafter, in order to remove the Si substrate 30, the side surfaces of the pedestal substrate 40 and the wafer are covered with electron wax, and etching is performed by mixing 70% hydrofluoric acid, 60% nitric acid, and glacial acetic acid at a ratio of 5: 2: 2. The liquid was used to dissolve and remove the Si substrate 30, exposing the surface of the buffer layer 32 made of AlN. At this time, the selective growth mask 31 was also removed by the etchant. The p-type electrode 38 was exposed in the portion where the selective growth mask 31 was removed, and a portion was etched, but the etching was stopped by Au therebelow. By using such an etchant, the etching rate was low for a nitride-based compound semiconductor such as AlN, selective etching was performed favorably, and the surface of the exposed AlN buffer layer became flat. The electron wax was removed with an organic solvent such as acetone, and after removing the insulating buffer layer 32 made of AlN by dry etching, the n-type semiconductor layer 33 made of Si-doped GaN was exposed.
[0027]
Next, 200 nm thick ITO was formed as the n-type electrode 41 on the surface of the n-type semiconductor layer 33 made of Si-doped GaN by sputtering. By heating to 250 ° C. during the sputtering, good ohmic contact was obtained between the n-type semiconductor layer 33 made of Si-doped GaN and the n-type electrode 41. Subsequently, a 10-nm-thick Mo adhesion layer 42a and a 500-nm-thick Au bonding layer 42b were formed on the n-type electrode 41 as bonding pad electrodes. At this time, the bonding pad electrode 42 was formed by a lift-off method using ordinary photolithography so that the pad electrode 42 for bonding was located inside the current blocking layer 37 when viewed from above the n-type electrode 41. Next, in order to remove ITO in a portion to be diced, portions other than the dicing line were covered with a photoresist, and the ITO was removed by wet etching with an iron chloride-based etchant. FIG. 4B shows a state at this stage.
[0028]
Finally, dicing was performed along the dotted line in FIG. FIG. 4C is a cross-sectional view of the light emitting device manufactured as described above. Since the manufactured light emitting element does not emit light immediately below the bonding pad electrode made of a thick metal that does not transmit light, useless light emission can be eliminated. In addition, since the p-type electrode had a high reflectance, the light extraction efficiency was good, the driving voltage was low, the peeling did not occur even in a long-term energizing test, and the reliability was high. In this embodiment, AlN is not doped with impurities. However, if AlN is doped with Si, an n-type electrode may be formed on Si-doped AlN without removing AlN by dry etching. Further, in the present embodiment, the thick film Ni of the pedestal substrate is formed by the electrolytic plating method. However, an electroless plating method may be used, and other materials other than Ni may be used as long as they can be formed by the plating method. It is preferable to use a conductive material. Further, in this embodiment, ITO is formed on the entire surface of the n-type semiconductor layer as the n-type electrode, but the pad electrode may be formed without forming the ITO. In this case, it is preferable that the pad electrode is formed by forming Hf to a thickness of 5 nm and then forming Al to a thickness of 150 nm.
[0029]
Example 3
FIG. 5A is a cross-sectional view illustrating a state in which electrodes are formed on a pedestal substrate 59, and FIG. 5B is a cross-sectional view illustrating a state in which an n-type semiconductor layer 52 and the like are formed on a Si substrate 50. It is. FIG. 5C is a cross-sectional view illustrating a state after the thermal pressing. As shown in FIG. 5B, a Si-doped AlN buffer layer 51 and an n-type semiconductor layer 52 made of Si-doped GaN are formed on a Si substrate 50, and a GaN barrier layer and a well layer made of InGaN are formed thereon. The light emitting layer 53 of the multiple quantum well composed of was formed. A p-type AlGaN cladding layer 54 was formed on the light emitting layer 53, and a p-type GaN contact layer 55 was formed on the p-type cladding layer 54. Next, in order to form a current blocking region 56 on the surface of the p-type contact layer 55, a mask made of a photoresist is formed at that portion, and a 1.5 nm-thick Pd-contact electrode 57 is formed thereon as a p-type electrode 57. After depositing the layer 57a and the Ag high reflection layer 57b having a thickness of 150 nm, a current blocking region 56 was formed by a lift-off method.
[0030]
By performing a heat treatment at 500 ° C. for 3 minutes in a vacuum, the p-type contact layer 55 and the p-type electrode 57 were alloyed. By this heat treatment, a good ohmic junction between the p-type contact layer 55 and the p-type electrode 57 was obtained, and the adhesion was increased. Next, a 300-nm-thick AuSn-bonded metal layer 58a was deposited on the p-type electrode 57. Since the adhered metal layer 58a is in direct contact with the current blocking region 56, the current blocking region 56 does not form an ohmic junction but serves as a current blocking region. On the other hand, as shown in FIG. 5A, a Si substrate is prepared as the pedestal substrate 59, and a titanium layer 60a having a thickness of 15 nm and an aluminum layer 60b having a thickness of 150 nm are deposited on the pedestal substrate 59 as the ohmic electrodes 60. Formed. A 100 nm-thick Mo barrier metal layer 61 was deposited thereon, and a 300 nm-thick AuSn sticking metal layer 58b was deposited thereon.
[0031]
Next, the pasted metal layer 58a and the pasted metal layer 58b were joined, and they were joined by applying a pressure of 400 N while heating to 200 ° C. in a vacuum. The eutectic point of AuSn of the adhered metal is 230 ° C., and in this embodiment, the eutectic point was heat-welded at 200 ° C. which is lower than the eutectic point. FIG. 5C is a cross-sectional view illustrating a state after the thermal pressing. Subsequently, in order to remove the Si substrate 50, the pedestal substrate 59 side and the side surfaces of the wafer were covered with electron wax, and 70% hydrofluoric acid, 60% nitric acid and glacial acetic acid were mixed at a ratio of 5: 2: 2. The Si substrate 50 was dissolved and removed with an etchant to expose the surface of the buffer layer 51 made of Si-doped AlN. By using such an etchant, the etching rate was low for a nitride-based compound semiconductor such as AlN, selective etching was performed favorably, and the surface of the exposed AlN buffer layer became flat. The electron wax was removed with an organic solvent such as acetone.
[0032]
Thereafter, as shown in FIG. 6A, an n-type electrode 62 made of ITO having a thickness of 200 nm was formed on the buffer layer 51 made of Si-doped AlN by sputtering. By heating at 250 ° C. during the sputtering, a good ohmic contact was obtained between the buffer layer 51 made of Si-doped AlN and the n-type electrode 62. Subsequently, a Mo adhesion layer 63a having a thickness of 10 nm and an Au bonding layer 63b having a thickness of 500 nm are formed on the n-type electrode 62 as a bonding pad electrode 63 by a lift-off method using ordinary photolithography. did. FIG. 6B is a plan view when viewed from above the n-type electrode 62. As is clear from FIG. 6B, the pad electrode 63 for bonding is formed so as to fit inside the region where the current blocking layer 56 is formed.
[0033]
Thereafter, in order to remove the ITO at the portion to be diced, portions other than the dicing line were covered with a photoresist, and the ITO was removed by wet etching with an iron chloride-based etchant. Using the photoresist for the ITO etching as it is as the mask for the dry etching, the semiconductor layer in the portion to be diced was removed by the dry etching method. As a dry etching method, a portion not covered with the photoresist was etched by RIE until the p-type electrode 57 was exposed. Finally, it was divided into 300 μm squares by dicing. FIG. 6A is a cross-sectional view of the manufactured light emitting device.
[0034]
The light emitting device manufactured in this manner does not emit light immediately below the bonding pad electrode made of a thick metal that does not allow light to pass therethrough, so that unnecessary light emission can be eliminated. Further, since the p-type electrode has a high reflectance with respect to the light emitted from the light emitting layer, the light extraction efficiency was good. For this reason, it was found that peeling did not occur even at a low driving voltage even in a long-term energization test, and the reliability was high. In this embodiment, AlN doped with Si is used. However, non-doped AlN may be used for the buffer layer. In this case, after removing the Si substrate, part or all of the AlN is removed by dry etching, and SiN is removed. The n-type electrode may be formed by exposing the doped GaN layer. In this embodiment, a Si substrate is used as the base substrate, but other substrates may be used, and a conductive substrate is preferable. Further, the current blocking region was formed by not forming an ohmic electrode in the current blocking region. However, the surface of the p-type semiconductor layer in the portion serving as the current blocking region was slightly etched by dry etching to form an ohmic contact with the p-type electrode. Therefore, the current blocking region may be formed by dry etching.
[0035]
The embodiments and examples disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[0036]
【The invention's effect】
By providing the n-type electrode side as a main light extraction surface and providing a current blocking region, light extraction efficiency can be improved.
[Brief description of the drawings]
FIGS. 1A and 1B are cross-sectional views of a light-emitting element manufactured in Example 1 of the present invention, in which FIG. 1A is a cross-sectional view in the middle of manufacturing, and FIG. 1B is a cross-sectional view in a completed state.
FIG. 2 is a plan view of a light emitting device manufactured in Example 1 of the present invention.
FIG. 3 is a plan view when a mask is provided on a substrate in Embodiment 2 of the present invention.
4A and 4B are cross-sectional views of a light-emitting element manufactured in Example 2 of the present invention, in which FIG. 4A is a cross-sectional view when a pedestal substrate is formed, and FIG. 4B is a cross-sectional view before a substrate is divided. (C) is a cross-sectional view at the stage of completion.
5A and 5B are cross-sectional views of a light-emitting element manufactured in Example 3 of the present invention, in which FIG. 5A is a cross-sectional view illustrating a state in which electrodes are formed on a pedestal substrate, and FIG. It is sectional drawing showing the state in which the semiconductor layer etc. were formed, and (c) is sectional drawing showing the state after heat-pressure welding.
6A and 6B show a light emitting device manufactured in Example 3 of the present invention, wherein FIG. 6A is a sectional view and FIG. 6B is a plan view.
FIG. 7 is a cross-sectional view of a conventional light emitting device.
[Explanation of symbols]
10 Si substrate, 11 buffer layer, 12 n-type semiconductor layer, 13 light emitting layer, 14 p-type cladding layer, 15 p-type contact layer, 16 current blocking layer, 17 p-type electrode, 17 a adhesion layer, 17 b high reflection layer, 18 plating base layer, 19 pedestal substrate, 20 n-type electrode, 21 bonding pad electrode.

Claims (15)

In a light-emitting element in which a p-type electrode, a p-type semiconductor layer, a light-emitting layer, an n-type semiconductor layer, and an n-type electrode are sequentially formed on a pedestal substrate, and the n-type electrode side is a main light extraction surface. A nitride-based compound semiconductor light emitting device, wherein a current blocking layer is provided in a part between the p-type semiconductor layer and the p-type electrode. A part of the n-type electrode functions as a bonding pad electrode, or a bonding pad electrode is formed on the n-type electrode, and the bonding pad electrode receives light emitted from the light emitting layer. The bonding pad electrode is formed so as to be located inside a region where the current blocking layer is formed, as viewed from above the n-type electrode. 2. The nitride-based compound semiconductor light-emitting device according to 1. The nitride-based compound semiconductor light-emitting device according to claim 1, wherein the n-type electrode is a transparent conductive film. The nitride-based compound semiconductor light emitting device according to claim 1, wherein the pedestal substrate is opaque to light emitted from the light emitting layer. The nitride compound according to any one of claims 1 to 4, wherein the p-type electrode has a highly reflective layer having a reflectance of 60% or more at a wavelength of light emitted from the light emitting layer. Semiconductor light emitting device. 6. The current blocking layer according to claim 1, wherein the current blocking layer has at least one of a high resistance layer having a specific resistance of 1 Ωcm or more, an n-type semiconductor layer, and a Schottky junction layer. Nitride semiconductor light emitting device. The nitride-based compound semiconductor light emitting device according to claim 1, wherein the highly reflective layer in the p-type electrode contains Ag. The nitride-based compound semiconductor light emitting device according to claim 1, wherein the pedestal substrate is made of a metal or an alloy. 9. The nitride-based compound semiconductor light emitting device according to claim 1, wherein said pedestal substrate is a Si substrate. Sequentially forming an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer on a substrate;
Forming a current blocking layer on a part of the p-type semiconductor layer, and then forming a p-type electrode;
Forming a pedestal substrate on the p-type electrode;
Removing a part or the whole of the substrate to expose a part or the whole of the n-type semiconductor layer. The method of manufacturing a nitride-based compound semiconductor light emitting device according to claim 10, further comprising a step of performing a heat treatment at 300 ° C. to 700 ° C. after forming the p-type electrode. The method according to claim 10, wherein the substrate is a Si substrate. A part or the whole of the Si substrate is removed by an etching solution containing hydrofluoric acid and nitric acid, and the n-type semiconductor layer formed on the Si substrate functions as an etching stop layer. A method for manufacturing a nitride-based compound semiconductor light-emitting device according to claim 10. 14. The method according to claim 10, wherein the pedestal substrate is formed on the p-type electrode by a plating method. The method according to claim 10, wherein the pedestal substrate is a Si substrate, and is formed on the p-type electrode by thermocompression bonding.

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