JP2019212875A - Light emitting element and manufacturing method thereof - Google Patents

Abstract

ABSTRACT: To provide a light emitting element of a type manufactured by joining window layer/support substrates through a dielectric film such as a SiOlayer and removing a starting substrate with improved light extraction efficiency and a manufacture method thereof.SOLUTION: A light emitting element includes a window layer/support substrate, a light emitting unit including a second conductive type second semiconductor layer, an active layer, and a first conductive type first semiconductor layer provided in this order on the window layer/support substrate, and the light emitting element includes a removed portion from which at least the first semiconductor layer and the active layer are removed, a non-removal portion other than removal portion, a first ohmic electrode provided in the non-removal portion, and a second ohmic electrode provided in the removal portion, is obtained by bonding the window layer/support substrate and the light emitting unit via a dielectric film, and includes an antireflection layer between the light emitting unit and the dielectric film.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a light emitting element and a method for manufacturing the light emitting element.

  A product such as a chip-on-board (COB) is an LED chip mounting method that is excellent in heat dissipation from the LED element and is employed in applications such as lighting. When mounting an LED on a COB or the like, flip mounting in which a chip is directly bonded to a board is essential. In order to realize flip mounting, it is necessary to manufacture a flip chip in which energization pads having different polarities are provided on one surface of a light emitting element. Further, the surface opposite to the surface provided with the energization pad needs to be made of a material having a light extraction function.

  When a flip chip is manufactured using yellow to red LEDs, an AlGaInP-based material is used for the light emitting layer. Since the AlGaInP-based material has no bulk crystal and the LED portion is formed by an epitaxial method, a material different from AlGaInP is selected for the starting substrate. In many cases, GaAs or Ge is selected as the starting substrate, and these substrates have a property of absorbing light with respect to visible light. Therefore, when a flip chip is manufactured, the starting substrate is removed. However, since the epitaxial layer forming the light emitting layer is an extremely thin film, it cannot stand by itself after the starting substrate is removed. Therefore, it is necessary to replace the starting substrate with a material / structure having a function as a supporting substrate having a thickness sufficient to make the light emitting layer transparent to the emission wavelength and function as a window layer and to be self-supporting. is there.

  GaP, GaAsP, sapphire, or the like is selected as a replacement material having the function of the window layer / supporting substrate. Whichever material is selected, since it is a different material from the AlGaInP-based material, mechanical properties such as lattice constant, thermal expansion coefficient and Young's modulus are different from those of the AlGaInP-based material.

As such a technique, Patent Document 1 discloses a method of forming GaP as a window layer and supporting substrate by crystal growth and direct bonding. In this technique, the size of the light emitting element wafer is determined by the size of the GaP substrate to be directly bonded, and it is difficult to increase the diameter of the wafer. For this reason, even if this technique is suitable for manufacturing a small light emitting element, it is not suitable for manufacturing a large light emitting element. Patent Document 2 discloses a method of forming GaP by crystal growth as a window layer and supporting substrate. According to this technology, since the GaP substrate is not bonded, the size of the bonded substrate is not restricted. However, large lattice irregularities exist in the GaP and AlGaInP light emitting layer portions, and warpage occurs. When the wafer diameter is increased, the warpage increases, and there is a problem that the device process becomes difficult when a large wafer is used. For this reason, even if this technique is suitable for manufacturing a small light emitting element, it is not suitable for manufacturing a large light emitting element. Patent Document 3 discloses a technique for joining a transparent substrate made of sapphire or the like as a window layer and supporting substrate via an SiO ₂ layer. With this technique, even a large-diameter wafer can reduce warpage and bonding failure. However, in this case, since reflection occurs between the semiconductor portion and the SiO ₂ layer, the light extraction efficiency to the transparent substrate side is disadvantageous.

JP-A-2015-12028 Japanese Patent Laying-Open No. 2015-5551 JP 2017-126720 A

The present invention has been made in view of the above problems, and is a type of light emitting device manufactured by joining a window layer / support substrate via a dielectric film such as a SiO ₂ layer and removing the starting substrate. Thus, an object of the present invention is to provide a light emitting device with improved light extraction efficiency and a method for manufacturing the same.

  In order to achieve the above object, in the present invention, a window layer / support substrate, a second conductivity type second semiconductor layer provided on the window layer / support substrate, an active layer, and a first conductivity type A light emitting device having a light emitting portion including a first semiconductor layer in this order, wherein the light emitting device includes at least a removed portion from which the first semiconductor layer and the active layer are removed, and a non-removed portion other than the removed portion. A first ohmic electrode provided in the non-removable part and a second ohmic electrode provided in the removed part, and the window layer / support substrate and the light emitting part Provided is a light-emitting element which is bonded through a dielectric film and has an antireflection layer between the light-emitting portion and the dielectric film.

  With such a light-emitting element, light emitted from the light-emitting portion can be suppressed from being reflected by the dielectric film, so that light extraction efficiency can be improved.

At this time, it is preferable that the dielectric film is a SiO ₂ layer, and the antireflection layer has a refractive index of 1.6 or more and 2.9 or less.

  With such a dielectric film and antireflection layer, the light extraction efficiency can be improved more reliably.

  The dielectric film is composed of a first dielectric film provided on the light emitting unit side and a second dielectric film provided on the window layer / supporting substrate side, and the first dielectric film is provided. It is preferable that the body film and the second dielectric film are directly joined.

  With such a dielectric film, there is little peeling due to poor bonding.

  The dielectric film is composed of a first dielectric film provided on the light emitting unit side and a second dielectric film provided on the window layer / supporting substrate side, and the first dielectric film is provided. The body film and the second dielectric film are preferably bonded via an adhesive.

  Even with such a dielectric film, peeling due to poor bonding is reduced.

  According to the present invention, there is also provided a method of manufacturing a light emitting device, the step of preparing a starting substrate, and the first conductive type first semiconductor layer, the active layer, and the second by epitaxial growth on the starting substrate. A step of forming a laminated structure including a light emitting part in which conductive second semiconductor layers are sequentially laminated, and a step of producing a light emitting element wafer; and a step of forming a first dielectric film on the light emitting element wafer A step of preparing a window layer / support substrate, a step of forming a second dielectric film on the window layer / support substrate, the light emitting element wafer and the window layer / support substrate, Bonding through one dielectric film and a second dielectric film, producing a bonded substrate, removing the starting substrate in the bonded substrate, and exposing the first semiconductor layer; In a partial region of the bonding substrate, at least the Forming a removed portion from which the semiconductor layer and the active layer have been removed and a non-removed portion other than the removed portion; a first ohmic electrode on the surface of the non-removed portion; and a second ohmic on the surface of the removed portion A step of forming an electrode, and a step of separating the light emitting element from the bonding substrate into a dice using a scribing and breaking method using laser light, and the step of forming the first dielectric film. Before, a method for manufacturing a light emitting device is provided, wherein an antireflection layer is formed on the light emitting portion of the light emitting device wafer.

  With such a method of manufacturing a light emitting device, it is possible to suppress the light emitted from the light emitting portion from being reflected by the dielectric film, and thus manufacturing a light emitting device capable of improving the light extraction efficiency. can do.

At this time, it is preferable that the first dielectric film and the second dielectric film are SiO ₂ layers, and the refractive index of the antireflection layer is 1.6 or more and 2.9 or less.

  By using such a first dielectric film, a second dielectric film, and an antireflection layer, the light extraction efficiency can be improved more reliably.

  Further, at this time, in the step of manufacturing the bonding substrate, the window layer supporting substrate and the light emitting element wafer may be directly bonded to the first dielectric film and the second dielectric film. preferable.

  If the dielectric films are bonded in this way, peeling due to bonding failure can be reduced.

  At this time, in the step of manufacturing the bonding substrate, the window layer / supporting substrate and the light emitting element wafer are bonded to the first dielectric film and the second dielectric film with an adhesive. It is preferable.

  Even when the dielectric films are bonded in this way, peeling due to bonding failure can be reduced.

  As described above, according to the light-emitting element of the present invention, light emitted from the light-emitting portion can be suppressed from being reflected by the dielectric film, and thus light extraction efficiency can be improved.

In 1st embodiment of this invention, it is the schematic of the wafer for light emitting elements in which the antireflection layer and the 1st dielectric film were formed. In 1st embodiment of this invention, it is the schematic of the window layer and support substrate in which the dielectric film was formed. It is the schematic of the joining board | substrate formed in 1st embodiment of this invention. In the first embodiment of the present invention, it is a schematic view of a structure in which a starting substrate and a selective etching layer are removed. In 1st embodiment of this invention, it is the schematic of the structure in which the removal part was formed. In 1st embodiment of this invention, it is the schematic of the structure which formed the 3rd dielectric material layer and provided the opening part. In 1st embodiment of this invention, it is the schematic of the structure in which the 1st ohmic electrode and the 2nd ohmic electrode were formed. In 1st embodiment of this invention, it is the schematic of the structure in which the coating | coated part and the opening part were formed. In 1st embodiment of this invention, it is the schematic of the structure which exposed a part of window layer and support substrate. It is the schematic of the light emitting element before scribing of 1st embodiment of this invention. In 2nd embodiment of this invention, it is the schematic of the wafer for light emitting elements in which the antireflection layer, the 1st dielectric film, and the 1st contact bonding layer were formed. In 2nd embodiment of this invention, it is the schematic of the window layer and support substrate in which the dielectric film and the 2nd contact bonding layer were formed. It is the schematic of the joining board | substrate formed in 2nd embodiment of this invention. In the second embodiment of the present invention, it is a schematic view of a structure in which the starting substrate and the selective etching layer are removed. It is the schematic of the structure in which the removal part was formed in 2nd embodiment of this invention. In 2nd embodiment of this invention, it is the schematic of the structure which formed the 3rd dielectric material layer and provided the opening part. In 2nd embodiment of this invention, it is the schematic of the structure in which the 1st ohmic electrode and the 2nd ohmic electrode were formed. In 2nd embodiment of this invention, it is the schematic of the structure in which the coating | coated part and the opening part were formed. In 2nd embodiment of this invention, it is the schematic of the structure which exposed a part of window layer and support substrate. It is the schematic of the light emitting element before scribing of 2nd embodiment of this invention. It is a figure which shows the improvement rate of the integrated output of light emission about what changed the material of the antireflection layer of Example 1 (Examples 1-1 to 1-6) and a comparative example. It is a figure which shows the improvement rate of the integrated output of light emission of Example 1-1, Example 2, and a comparative example. It is a figure which shows the relationship between the refractive index of the antireflection layer of this invention, and a total reflection angle.

As described above, in a light emitting device manufactured by joining a window layer / supporting substrate through a dielectric film such as a SiO ₂ layer and removing the starting substrate, a light emitting device with improved light extraction efficiency is provided. It was sought after.

As a result of intensive studies on the above problems, the inventors of the present invention have a light-emitting device manufactured by joining a window layer / support substrate through a dielectric film such as a SiO ₂ layer and removing the starting substrate. The inventors have found that the light extraction efficiency can be improved by providing an antireflection layer between the light emitting portion and the dielectric film, and the present invention has been completed.

That is, the present invention includes a window layer / support substrate, a second conductivity type second semiconductor layer, an active layer, and a first conductivity type first semiconductor layer provided on the window layer / support substrate. A light-emitting element having a light-emitting portion including in this order,
The light emitting device has a removed portion from which at least the first semiconductor layer and the active layer have been removed, and a non-removed portion other than the removed portion, and a first ohmic electrode provided in the non-removed portion And a second ohmic electrode provided in the removal portion,
The window layer / support substrate and the light emitting part are bonded via a dielectric film,
The light-emitting element includes an antireflection layer between the light-emitting portion and the dielectric film.

  Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[Light Emitting Element of First Embodiment]
First, the light emitting device of the first embodiment of the present invention will be described.

  FIG. 10 shows a schematic diagram of a light-emitting element 1000 before scribing according to the present invention.

As shown in FIG. 10, the light emitting device according to the first embodiment of the present invention includes a transparent substrate 120 (window layer / support substrate) 120 as a window layer / support substrate made of GaP, GaAsP, sapphire, and the like. A second dielectric film 122 having a thickness of 0.05 to 1.0 μm and a first dielectric film 112 having a thickness of 0.05 to 1.0 μm are formed on the surface. The dielectric film can be SiO ₂ or SiN _x .

  On the first dielectric film 112, an antireflection layer (AR layer) 111 having an antireflection function is disposed.

_{Al z Ga 1-z As (} 0 ≦ z ≦ 1) or _{GaAs w P 1-w (0} ≦ w ≦ 1) having a thickness of 0.5~5.0μm consisting current spreading layer 107 thereon, InGaP Alternatively, an intermediate composition layer 106 made of AlInP and having a thickness of 0.1 to 1.0 μm, (Al _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) or Al _z Ga _1-z As (0 ≦ z ≦ 1) and a second conductivity type second semiconductor layer 105 having a thickness of 0.5 to 1.0 μm, an active layer 104 having a thickness of 0.1 to 1.0 μm, a thickness A light emitting unit 108 including the first conductive type first semiconductor layer 103 of 0.5 to 1.0 μm in this order is formed.

Active layer 104, depending on the emission wavelength _{(Al x Ga 1-x)} y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) or _Al z _{Ga 1-z} As ( 0 ≦ z ≦ 0.45). When it is applied to visible light illumination, it is preferable to select AlGaInP, and when it is applied to infrared illumination, it is preferable to select AlGaAs or InGaAs. However, the design of the active layer 104 is not limited to the above materials because the extraction wavelength can be adjusted in addition to a suitable wavelength resulting from the material composition by using a superlattice or the like.

  AlGaInP or AlGaAs is selected for the first semiconductor layer 103 and the second semiconductor layer 105, and the selection does not necessarily have to be the same material system as that of the active layer 104.

  Further, the light emitting device includes a removal portion 136 from which the active layer 104 and the first conductive type first semiconductor layer 103 are removed, and a non-removal portion 135 other than the removal portion 136. At this time, the second conductive type second semiconductor layer 105 and the intermediate composition layer 106 may also be removed to form a removed portion. And it has the 1st ohmic electrode 185 provided on the surface of the 1st semiconductor layer 103 of the non-removal part 135, and the 2nd ohmic electrode 186 provided on the surface of the removal part 136.

  With such a light emitting element, the presence of the antireflection layer 111 can suppress the light emitted from the light emitting unit 108 from being reflected by the dielectric film 132, thereby improving the light extraction efficiency. Can do.

For the antireflection layer 111, it is preferable to select a material having a refractive index lower than that of GaP and higher than that of the dielectric film, which is about 1.6 or more and 2.9 or less. More preferred is a range of 2 to 2.5. Specifically, the antireflection layer 111 is made of AlN, GaN, Ta ₂ O ₃ , TiO ₂ , ZnS, ZnSe, or the like. The same effect can be obtained even if the antireflection layer 111 is composed of two or more layers.

FIG. 23 is a diagram showing the relationship between the refractive index of the antireflection layer and the total reflection angle. For example, when there is no antireflection layer, when light enters the dielectric film 132 made of SiO ₂ (refractive index 1.5) from the current diffusion layer 107 made of GaP (refractive index 3), the total reflection angle θ is Since sin θ = 1.5 / 3, it is 30 °. Therefore, the reflection angle of the antireflection layer 111 is such that the total reflection angle in the incidence of light from the current diffusion layer 107 to the antireflection layer 111 and the incidence of light from the antireflection layer 111 to the dielectric film 132 exceeds 30 °. It is sufficient to select a refractive index. 23, from 1.6 to 2.9, the total reflection in the incidence of light from the current diffusion layer 107 to the antireflection layer 111 and the incidence of light from the antireflection layer 111 to the dielectric film 132. Since the angle exceeds 30 °, a material having a refractive index in such a range may be used for the antireflection layer 111.

  With such a dielectric film and antireflection layer, the light extraction efficiency can be improved more reliably.

  The first dielectric film 112 and the second dielectric film 122 of this light emitting element are directly bonded without using an adhesive to form a dielectric film 132, thereby realizing bonding with less peeling due to bonding failure. can do.

[Method for Manufacturing Light-Emitting Element of First Embodiment]
Next, the manufacturing method of the light emitting element of 1st embodiment is demonstrated using FIGS.

  First, as shown in FIG. 1, a starting substrate 100 having a crystal axis inclined in the [110] direction from the [001] direction is prepared. As the starting substrate 100, GaAs or Ge can be preferably used. If the starting substrate 100 is selected from the above materials, the material of the active layer 104 can be epitaxially grown in a lattice-matched system, so that the quality of the active layer 104 can be easily improved, and the luminance and life characteristics can be improved. .

Next, for example, (Al _x Ga _1-x ) _y In _{1 is formed} on the starting substrate 100 by, for example, MOVPE (metal organic vapor phase epitaxy), MBE (molecular beam epitaxy), or CBE (chemical beam epitaxy). _-Y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) or Al _z Ga _1-z As (0 ≦ z ≦ 1) and the first conductivity type first having a thickness of 0.5 to 1.0 μm. The semiconductor layer 103, the active layer 104 having a thickness of 0.1 to 1.0 μm, and the second semiconductor layer 105 of the second conductivity type having a thickness of 0.5 to 1.0 μm are epitaxially grown in this order. An intermediate composition layer 106 having a thickness of 0.1 to 1.0 μm and a current diffusion layer 107 having a thickness of 0.5 to 5.0 μm are epitaxially grown thereon to form a stacked structure including the light emitting portion 108. A light emitting device wafer 110 is manufactured.

  A selective etching layer 102 for removing the substrate is inserted between the starting substrate 100 and the first semiconductor layer 103.

As the current diffusion layer 107, AlGaAs, GaAsP, or GaP can be suitably used. When the current spreading layer 107 is formed of GaAs _x P _1-x (0 ≦ x <1), the intermediate composition layer 106 is preferably formed of InGaP or AlInP. Since there is a lattice mismatch between GaAs _x P _1-x (x ≠ 1) and the AlGaInP-based material or AlGaAs-based material, GaAs _x P _1-x (x ≠ 1) Threading dislocation enters. The threading dislocation density can be adjusted by the composition x.

Next, an antireflection layer 111 having an antireflection function is disposed on the current diffusion layer 107. For the antireflection layer 111, it is preferable to select a material having a refractive index lower than that of GaP and higher than that of the dielectric film and having a value of 1.6 to 2.9. More preferred is a range of 2 to 2.5. Specifically, the antireflection layer 111 is made of AlN, GaN, Ta ₂ O ₃ , TiO ₂ , ZnS, ZnSe, or the like. The same effect can be obtained even if the antireflection layer 111 is composed of two or more layers.

  With such a dielectric film and antireflection layer, the light extraction efficiency can be improved more reliably.

Next, a first dielectric film 112 made of SiO 2 or SiN _{x is formed} on the antireflection layer 111 with a thickness of 0.4 μm, for example.

Next, as shown in FIG. 2, a dielectric film 122 made of SiO ₂ or SiN _x is formed on the window layer / support substrate 120 such as GaP, sapphire, or quartz.

Next, as shown in FIG. 3, the first dielectric film 112 and the second dielectric film 122 are opposed to each other, and pressure and heat are applied in a vacuum or a reduced pressure atmosphere to thereby form the first dielectric layer 112 The second dielectric layer 122 is directly bonded, the dielectric film 132 is formed, and the bonding substrate 130 is formed. Adhesion is performed by pressure bonding under conditions where the pressure is 6 N / cm ² or more and the temperature is 150 ° C. or more. In particular, if bonding is performed under conditions that reach 30 N / cm ² and 350 ° C. or higher, it is preferable because bonding can be performed more reliably.

  Next, as shown in FIG. 4, the starting substrate 100 is removed from the bonding substrate 130 by chemical etching. The chemical etchant preferably has an etching selectivity with respect to the AlGaInP-based material, and is generally removed with an ammonia-containing etchant. After removing the starting substrate 100, the selective etching layer 102 is removed to form a structure 131 having a first surface 135 (non-removed portion). The selective etching layer 102 is removed with a mixed solution of hydrogen peroxide and acid that etches the AlGaInP-based material.

  Before and after the removal of the starting substrate 100, a surface opposite to the bonding surface of the visible transparent substrate 120 may be roughened by lapping or etching to provide an additional antireflection effect.

  Next, as shown in FIG. 5, a part of the first surface 135 is cut away from the structure 131 to form a second surface (removal part) 136.

Next, as shown in FIG. 6, the third dielectric layer 180 is formed so as to cover the cut-out side surface 137, and the opening 181 is provided. The third dielectric layer 180 is preferably SiO ₂ or SiN _x . As a method for forming the third dielectric layer 180, any of a sol-gel method, a sputtering method, and a CVD method can be selected. Next, the opening 181 is formed by depositing the third dielectric layer 180, forming a mask portion by photolithography, and forming an exposed portion by wet etching using BHF.

  Next, as shown in FIG. 7, a first ohmic electrode 185 is formed on a part of the first surface (non-removed part) 135, and a second ohmic electrode 186 is formed on a part of the second surface 136.

  Next, as shown in FIG. 8, a cover 190 and an opening 191 that cover the entire first surface 135 and a part of the second surface 136 are formed of a photoresist.

Next, as shown in FIG. 9, the opening 191 is removed by a dry etching method, and a part of the window layer / supporting substrate 120 is exposed to form an exposed portion 192. The removal of the AlGaInP layer can be performed in a mixed atmosphere of Cl ₂ containing gas and Ar in the ICP apparatus, and the removal of the dielectric layer of SiO ₂ or SiN _x can be carried out in a mixed atmosphere of F containing gas and Ar. . The pressure atmosphere is 0.5 Pa, and the output is 300 W plasma. The removal of the layer using the Cl ₂ containing gas and the removal of the layer using the F containing gas can also be performed in separate chambers.

  Next, as shown in FIG. 10, the covering portion 190 is removed. After removing the covering portion 190, the exposed portion 192 is irradiated with a laser to form a scribe portion 193. Then, the light emitting element 1000 before scribing is subjected to a braking process along the scribe part 193 to be diced to produce a light emitting element.

  With such a method of manufacturing a light emitting element, the presence of the antireflection layer 111 can suppress the light emitted from the light emitting unit 108 from being reflected by the dielectric film, thereby improving the light extraction efficiency. The light emitting element which can be made to provide can be provided.

[Light Emitting Element of Second Embodiment]
Next, the light emitting device of the second embodiment of the present invention will be described.

  FIG. 20 shows a schematic view of the light emitting device 2000 before scribing according to the second embodiment of the present invention.

As shown in FIG. 20, the light emitting device of the second embodiment of the present invention is formed on a transparent substrate as a window layer / supporting substrate 220 made of GaP, GaAsP, sapphire, etc. A second dielectric film 222 having a thickness of 05 to 1.0 μm and a first dielectric film 212 having a thickness of 0.05 to 1.0 μm are formed. The dielectric film can be SiO ₂ or SiN _x .

  An antireflection layer 211 having an antireflection function is disposed on the first dielectric film 212.

On top of this, a current diffusion layer 207 having a thickness of 0.5 to 5.0 μm made of Al _z Ga _1-z As (0 ≦ z ≦ 1) or GaAs _w P _1-w (0 ≦ w ≦ 1), InGaP Alternatively, an intermediate composition layer 206 made of AlInP and having a thickness of 0.1 to 1.0 μm, (Al _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) or Al _z Ga _1-z As (0 ≦ z ≦ 1), a second conductive type second semiconductor layer 205 having a thickness of 0.5 to 1.0 μm, an active layer 204 having a thickness of 0.1 to 1.0 μm, and a thickness A light emitting unit 208 including the first conductive type first semiconductor layer 203 of 0.5 to 1.0 μm in this order is formed.

The active layer 204 has (Al _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) or Al _z Ga _1-z As (0 ≦ z ≦ 0.45). When it is applied to visible light illumination, it is preferable to select AlGaInP, and when it is applied to infrared illumination, it is preferable to select AlGaAs or InGaAs. However, the design of the active layer 204 is not limited to the above materials because the extraction wavelength can be adjusted in addition to a suitable wavelength due to the material composition by using a superlattice or the like.

  AlGaInP or AlGaAs is selected for the first semiconductor layer 203 and the second semiconductor layer 205, and the selection does not necessarily have to be the same material system as that of the active layer 204.

  Further, the light emitting element has a removal portion 236 from which the active layer 204 and the first conductive type first semiconductor layer 203 are removed, and a non-removal portion 235 other than the removal portion 236. At this time, the second conductive type second semiconductor layer 205 and the intermediate composition layer 206 may also be removed to form a removed portion. And it has the 1st ohmic electrode 285 provided on the surface of the 1st semiconductor layer 203 of the non-removal part 235, and the 2nd ohmic electrode 286 provided on the surface of the removal part 236.

  In such a light emitting element, the presence of the antireflection layer 211 can suppress the light emitted from the light emitting unit 208 from being reflected by the dielectric film, thereby improving the light extraction efficiency. it can.

For the same reason as the light emitting device of the first embodiment, the antireflection layer 211 has a refractive index lower than the refractive index of the window layer / supporting substrate 220 and higher than the refractive index of the dielectric film, not less than 1.6 and not more than 2.9. It is preferable to select a material of a degree. More preferred is a range of 2 to 2.5. Specifically, the antireflection layer 211 is made of AlN, GaN, Ta ₂ O ₃ , TiO ₂ , ZnS, ZnSe, or the like. The same effect can be obtained even if the antireflection layer 211 is composed of two or more layers.

  With such a dielectric film and antireflection layer, the light extraction efficiency can be improved more reliably.

  The first dielectric film 212 and the second dielectric film 222 of this light-emitting element are bonded through an adhesive to form a dielectric film 232, thereby realizing bonding with less peeling due to poor bonding. Can do.

[Method for Manufacturing Light-Emitting Element of Second Embodiment]
Next, the manufacturing method of the light emitting element of 2nd embodiment is demonstrated using FIGS.

  First, as shown in FIG. 11, a starting substrate 200 having a crystal axis inclined in the [110] direction from the [001] direction is prepared. As the starting substrate 200, GaAs or Ge can be preferably used. If the starting substrate 200 is selected from the above materials, the material of the active layer 204 can be epitaxially grown in a lattice-matched system, so that the quality of the active layer can be easily improved, and the luminance can be increased and the life characteristics can be improved.

Next, for example, (Al _x Ga _1-x ) _y In _{1 is formed} on the starting substrate 200 by, for example, MOVPE (metal organic vapor phase epitaxy), MBE (molecular beam epitaxy), or CBE (chemical beam epitaxy). _-Y P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) or Al _z Ga _1-z As (0 ≦ z ≦ 1) and the first conductivity type first having a thickness of 0.5 to 1.0 μm. The semiconductor layer 203, the active layer 204 having a thickness of 0.1 to 1.0 μm, and the second semiconductor layer 205 of the second conductivity type having a thickness of 0.5 to 1.0 μm are epitaxially grown in this order. An intermediate composition layer 206 having a thickness of 0.1 to 1.0 μm and a current diffusion layer 207 having a thickness of 0.5 to 5.0 μm are epitaxially grown thereon to form a stacked structure including the light emitting portion 208. A light emitting device wafer 210 is manufactured.

  A selective etching layer 202 for removing the substrate is inserted between the starting substrate 200 and the first semiconductor layer 203.

As the current diffusion layer 207, AlGaAs, GaAsP, or GaP can be suitably used. When the current spreading layer 207 is formed of GaAs _x P _1-x (0 ≦ x <1), the intermediate composition layer 206 is preferably formed of InGaP or AlInP. Since there is a lattice mismatch between GaAs _x P _1-x (x ≠ 1) and the AlGaInP-based material or AlGaAs-based material, GaAs _x P _1-x (x ≠ 1) Threading dislocation enters. The threading dislocation density can be adjusted by the composition x.

Next, an antireflection layer 211 having an antireflection function is disposed on the current diffusion layer 207. For the antireflection layer 211, it is preferable to select a material having a refractive index lower than that of GaP and higher than that of the dielectric film and having a value not lower than 1.6 and not higher than 2.9. More preferred is a range of 2 to 2.5. Specifically, AlN, GaN, SiN _x , Ta ₂ O ₃ , TiO ₂ , ZnS, ZnSe and the like. The same effect can be obtained even if the antireflection layer 211 is composed of two or more layers.

  With such a dielectric film and antireflection layer, the light extraction efficiency can be improved more reliably.

Next, a first dielectric film 212 made of SiO ₂ or SiNx is formed on the antireflection layer 211 with a thickness of 0.4 μm, for example.

  Next, for example, a first adhesive layer 213 is formed by applying a BCB adhesive by spin coating. The thickness of the first adhesive layer 213 varies depending on the viscosity of the BCB adhesive and the rotational speed at the time of spin coating. For example, the thickness can be 0.5 μm at a rotational speed of 5000 rpm.

Next, as shown in FIG. 12, a dielectric film 222 made of SiO ₂ or SiN _x is formed on the window layer / support substrate 220 such as GaP, sapphire, or quartz.

  Next, for example, a BCB adhesive is applied to form the second adhesive layer 223. The thickness of the second adhesive layer 223 varies depending on the viscosity of the BCB adhesive and the rotational speed at the time of spin coating. For example, the thickness can be 0.5 μm at a rotational speed of 5000 rpm. Although the case where BCB is used as an adhesive is illustrated, the first adhesive layer 213 and the second adhesive layer 223 may be formed of other transparent and room temperature liquid members such as epoxy.

Next, as shown in FIG. 13, the first adhesive layer 213 and the second adhesive layer 223 are opposed to each other, and pressure and heat are applied in a vacuum or a reduced pressure atmosphere so that the first adhesive layer 213 and the second adhesive layer 223 are Bonding is performed using an adhesive to form the dielectric film 232, and the bonding substrate 230 is manufactured. Adhesion is performed by pressure bonding under conditions where the pressure is 6 N / cm ² or more and the temperature is 100 ° C. or more. In particular, it is preferable to perform bonding under conditions that reach 30 N / cm ² and 300 ° C.

  Next, as shown in FIG. 14, the starting substrate 200 is removed from the bonding substrate 230 by chemical etching. The chemical etchant preferably has an etching selectivity with respect to the AlGaInP-based material, and is generally removed with an ammonia-containing etchant. After removing the GaAs substrate 200, the selective etching layer 202 is removed to form a structure 231 having a first surface 235 (non-removed portion). The selective etching layer 202 is removed with a mixed solution of hydrogen peroxide and acid for etching the AlGaInP-based material.

  Before and after the starting substrate 200 is removed, an additional structure may be provided in which the surface opposite to the bonding surface of the visible transparent substrate 220 is roughened by lapping or etching to have an antireflection effect.

  Next, as shown in FIG. 15, a part of the first surface 235 is cut away from the structure 231 to form a second surface (removal part) 236.

Next, as shown in FIG. 16, the third dielectric layer 280 is formed so as to cover the cut-out side surface 237, and the opening 281 is provided. The third dielectric layer 280 is preferably SiO ₂ or SiN _x . As a method for forming the third dielectric layer 280, any of a sol-gel method, a sputtering method, and a CVD method can be selected. Next, after forming the third dielectric layer 280 in the opening 281, a mask portion is formed by photolithography, and an exposed portion is formed by wet etching using BHF.

  Next, as shown in FIG. 17, a first ohmic electrode 285 is formed on a part of the first surface 235, and a second ohmic electrode 286 is formed on a part of the second surface 236.

  Next, as shown in FIG. 18, a covering portion 290 and an opening 291 that cover the entire first surface 235 and a part of the second surface 236 are formed of a photoresist.

Next, as shown in FIG. 19, the opening 291 is removed by a dry etching method to expose a part 292 of the window layer / supporting substrate 220. The removal of the AlGaInP layer is performed in a mixed atmosphere of Cl ₂ containing gas and Ar in the ICP apparatus, and the removal of the SiO ₂ or SiNx dielectric layer and the BCB layer is carried out in a mixed atmosphere of F containing gas and Ar. Can do. The pressure atmosphere is 0.5 Pa, and the output is 300 W plasma. The removal of the layer using the Cl ₂ containing gas and the removal of the layer using the F containing gas can also be performed in separate chambers.

  Next, as shown in FIG. 20, the covering portion 290 is removed. After removing the covering portion 290, the exposed portion 292 is irradiated with a laser to form a scribe portion 293. Then, the light emitting element 2000 before scribing is subjected to a braking process along the scribe part 293 to be diced to manufacture a light emitting element.

  With such a method for manufacturing a light emitting element, the presence of the antireflection layer 211 can suppress the light emitted from the light emitting unit 208 from being reflected by the dielectric film, thereby improving the light extraction efficiency. The light emitting element which can be made to provide can be provided.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example and a comparative example, this invention is not limited to these.

[Example 1]
The light emitting element before scribing as shown in FIG. 10 was scribed to produce 10,000 light emitting elements. More specifically, the window layer and the supporting substrate made of GaP, the second thickness 0.5μm composed of SiO ₂ dielectric film, likewise the first dielectric film having a thickness of 0.5μm made of SiO ₂ An antireflection layer made of TiO ₂ (refractive index: 2.493) is formed thereon, a current diffusion layer made of AlGaAs with a thickness of 1.0 μm, an intermediate composition layer made of AlInP with a thickness of 0.5 μm, A light emitting unit is formed which includes a 1.0 μm thick p-type second semiconductor layer made of AlGaInP, a 0.5 μm thick active layer, and a 1.0 μm thick n type first semiconductor layer in this order. Yes. Furthermore, it has the removal part from which the active layer and the 1st conductivity type 1st semiconductor layer were removed, and the non-removal part other than a removal part. A first ohmic electrode having a thickness of 500 nm made of AuGeNi on the surface of the first semiconductor layer in the non-removed portion; and a second ohmic electrode having a thickness of 500 nm made of AuBe on the surface of the second semiconductor layer in the removed portion; have. Further, the first dielectric film and the second dielectric film were directly bonded without using an adhesive under the conditions of 30 N / cm ² and 350 ° C. (Example 1-1).

Moreover, the light emitting element was manufactured similarly to Example 1-1 except that the antireflection layer was manufactured using the material shown below instead of TiO ₂ (Examples 1-2 to 1-6). As the material for the antireflection layer, AlN (refractive index: 2.164) was used (Example 1-2). As a material for the antireflection layer, Ta ₂ O ₃ (refractive index: 2.165) was used (Example 1-3). As a material for the antireflection layer, ZnS (refractive index: 2.355) was used (Example 1-4). As a material for the antireflection layer, GaN (refractive index: 2.38) was used (Example 1-5). As a material for the antireflection layer, ZnSe (refractive index: 2.599) was used (Example 1-6).

[Example 2]
The light emitting elements before scribing as shown in FIG. 20 were scribed to produce 10,000 light emitting elements. More specifically, the window layer and the supporting substrate made of GaP, the second thickness 0.5μm composed of SiO ₂ dielectric film, likewise the first dielectric film having a thickness of 0.5μm made of SiO ₂ An antireflection layer made of TiO ₂ is formed thereon, a current diffusion layer made of AlGaAs having a thickness of 1.0 μm, an intermediate composition layer made of AlInP having a thickness of 0.5 μm, and a thickness made of AlGaInP. A light emitting portion including a 0 μm p-type second semiconductor layer, a 0.5 μm thick active layer, and a 1.0 μm thick n type first semiconductor layer in this order is formed. And it has the removal part from which the 1st semiconductor layer of the 1st conductivity type was removed, and the non-removal part other than a removal part. A first ohmic electrode having a thickness of 500 nm made of AuGeNi on the surface of the first semiconductor layer of the non-removed portion; and a second ohmic electrode having a thickness of 500 nm made of AuBe on the surface of the second semiconductor layer of the removed portion. have. Further, the first SiO ₂ film and the second SiO ₂ film were bonded under the conditions of 30 N / cm ² and 350 ° C. via the BCB adhesive layer.

[Comparative example]
10,000 light-emitting elements were produced in the same manner as in Example 1-1 except that the antireflection layer was not formed.

  FIG. 21 shows the improvement rate of the integrated output of light emission for the comparative example with the antireflection layer material of Example 1 changed (Examples 1-1 to 1-6) and the comparative example. Moreover, the improvement rate of the integrated output of light emission of Example 1-1, Example 2, and a comparative example is shown in FIG. The integrated output of each example when the integrated output when there was no antireflection layer (comparative example) was 100% was taken as the improvement rate.

  Thus, it was found that the integrated output is greatly improved when the antireflection layer is provided as compared with the case where the antireflection layer is not provided (comparative example). Therefore, the light-emitting element of the present invention can improve the light extraction efficiency because the light emitted from the light-emitting portion can be prevented from being reflected by the dielectric film.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

100, 200 ... starting substrate, 102, 202 ... selective etching layer,
103, 203 ... first semiconductor layer, 104, 204 ... active layer,
105, 205 ... second semiconductor layer, 106, 206 ... intermediate composition layer,
107, 207 ... current spreading layer, 108, 208 ... light emitting part,
110, 210 ... Wafer for light emitting element,
111, 211 ... antireflection layer (AR layer), 112, 212 ... first dielectric film,
120, 220 ... window layer and supporting substrate (transparent substrate),
122, 222 ... second dielectric film, 132, 232 ... dielectric film 120, 220 ... window layer and supporting substrate,
130, 230 ... bonded substrate, 131, 231 ... structure,
135, 235 ... non-removal part (first surface), 136, 236 ... removal part (second surface),
137, 237 ... side surface, 180, 280 ... third dielectric layer,
181, 191, 281, 291 ... opening,
185, 285 ... first ohmic electrode, 186, 286 ... second ohmic electrode,
190, 290 ... covering portion, 192, 292 ... exposed portion,
193, 293 ... scribe part, 213 ... first adhesive layer, 223 ... second adhesive layer,
1000, 2000: Light emitting element before scribing.

Claims (8)

A light emitting section including a window layer / support substrate, a second conductivity type second semiconductor layer, an active layer, and a first conductivity type first semiconductor layer provided on the window layer / support substrate in this order; A light emitting device comprising:
The light emitting device has a removed portion from which at least the first semiconductor layer and the active layer have been removed, and a non-removed portion other than the removed portion, and a first ohmic electrode provided in the non-removed portion And a second ohmic electrode provided in the removal portion,
The window layer / support substrate and the light emitting part are bonded via a dielectric film,
A light emitting device comprising an antireflection layer between the light emitting portion and the dielectric film. The light emitting device according to claim 1, wherein the dielectric film is a SiO ₂ layer, and the antireflection layer has a refractive index of 1.6 or more and 2.9 or less.   The dielectric film comprises a first dielectric film provided on the light emitting part side and a second dielectric film provided on the window layer / supporting substrate side, and the first dielectric film The light emitting device according to claim 1, wherein the second dielectric film and the second dielectric film are directly bonded.   The dielectric film comprises a first dielectric film provided on the light emitting part side and a second dielectric film provided on the window layer / supporting substrate side, and the first dielectric film The light emitting device according to claim 1, wherein the second dielectric film is bonded via an adhesive. A method of manufacturing a light emitting device,
Preparing a starting substrate;
A stacked structure including a light emitting portion in which a first conductive type first semiconductor layer, an active layer, and a second conductive type second semiconductor layer are sequentially stacked is formed on the starting substrate by epitaxial growth. Producing a wafer for use,
Forming a first dielectric film on the light emitting device wafer; and
Preparing a window layer and supporting substrate;
Forming a second dielectric film on the window layer and supporting substrate;
Bonding the light emitting element wafer and the window layer / support substrate via a first dielectric film and a second dielectric film, and producing a bonded substrate;
Removing the starting substrate and exposing the first semiconductor layer in the bonding substrate;
Forming a removed portion from which at least the first semiconductor layer and the active layer are removed and a non-removed portion other than the removed portion in a partial region of the bonding substrate;
Forming a first ohmic electrode on the surface of the non-removable part and forming a second ohmic electrode on the surface of the removed part;
A step of separating the light emitting element from the bonding substrate into a dice using a scribing and breaking method by laser light;
And an antireflection layer is formed on the light emitting portion of the light emitting element wafer before the step of forming the first dielectric film. 6. The first dielectric film and the second dielectric film are SiO ₂ layers, and the refractive index of the antireflection layer is 1.6 or more and 2.9 or less. Manufacturing method of light emitting element.   The step of producing the bonding substrate is characterized in that the first dielectric film and the second dielectric film are directly bonded to the window layer / supporting substrate and the light emitting element wafer. The manufacturing method of the light emitting element of Claim 5 or Claim 6.   In the step of manufacturing the bonding substrate, the window layer / supporting substrate and the light emitting element wafer are bonded to each other with the first dielectric film and the second dielectric film. The manufacturing method of the light emitting element of Claim 5 or Claim 6.

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