KR102496616B1 - Light emitting device and display device having thereof - Google Patents

Abstract

Embodiments include a light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer; an insulating layer disposed on the other side of the light emitting structure; a first electrode electrically connected to the first conductive semiconductor layer through the insulating layer; a second electrode electrically connected to the second conductive type semiconductor layer through the insulating layer; a first ohmic electrode electrically connected to the first conductive semiconductor layer; and a second ohmic electrode electrically connected to the second conductivity type semiconductor layer, wherein the active layer emits light in a red wavelength range, and the first conductivity type semiconductor layer has a first ohmic electrode in contact with the first ohmic electrode. It includes an ohmic layer, and the first ohmic layer discloses a light emitting device having a GaAs composition and a display device including the same.

Description

Light emitting device and display device including the same {LIGHT EMITTING DEVICE AND DISPLAY DEVICE HAVING THEREOF}

The embodiment relates to a light emitting device and a display device including the same.

A light emitting diode (LED) is one of light emitting devices that emits light when a current is applied thereto. A light emitting diode can emit light with high efficiency at a low voltage and thus has an excellent energy saving effect. Recently, the luminance problem of light emitting diodes has been greatly improved, and they are applied to various devices such as backlight units of liquid crystal display devices, electronic signboards, displays, and home appliances.

A light emitting diode having AlGaInP uses a GaAs substrate as a growth substrate, but in order to manufacture a flip chip type, it is necessary to remove the GaAs substrate to prevent light absorption. However, the GaAs substrate has a problem in that it is difficult to remove the existing LLO (Laser Lift-Off) process. Therefore, light emitting diodes having AlGaInP are mostly manufactured in a vertical type.

The embodiment provides a flip chip type red light emitting device.

In addition, a light emitting device having excellent light extraction efficiency is provided.

In addition, a light emitting device having excellent current spreading effect is provided.

In addition, a light emitting device having excellent ohmic contact is provided.

One embodiment of the present invention, a light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer; an insulating layer disposed on the other side of the light emitting structure; a first electrode electrically connected to the first conductive semiconductor layer through the insulating layer; a second electrode electrically connected to the second conductive type semiconductor layer through the insulating layer; a first ohmic electrode electrically connected to the first conductive semiconductor layer; and a second ohmic electrode electrically connected to the second conductivity type semiconductor layer, wherein the active layer emits light in a red wavelength range, and the first conductivity type semiconductor layer has a first ohmic electrode in contact with the first ohmic electrode. An ohmic layer is included, and the first ohmic layer has a GaAs composition.

A light transmitting substrate disposed on one side of the light emitting structure may be included.

An optical layer covering the light emitting structure may be included, and the light transmitting substrate may be disposed on the optical layer.

The first conductive semiconductor layer may include a first cladding layer, a first current spreading layer, and a first ohmic layer contacting the first ohmic electrode.

The first current spreading layer may have a smaller energy band gap than the first cladding layer and a larger energy band gap than the first ohmic layer.

The first cladding layer and the first current spreading layer may include Al, In, or P.

The first ohmic layer may include a dopant.

The first ohmic layer may have the highest doping concentration in the first conductivity type semiconductor layer.

The second conductive semiconductor layer may include a second cladding layer, a second current diffusion layer, and a second ohmic layer.

The second cladding layer may include Al, In, and P.

The second current spreading layer and the second ohmic layer may include Ga and P.

The second ohmic layer may include carbon.

The concentration of the carbon may be 5×10 ¹⁹ /cm ³ to 2×10 ²⁰ /cm ³ .

A panel according to an embodiment of the present invention includes an array substrate; a common wiring formed on the array substrate; a plurality of driving wires formed on the array substrate; a light emitting structure comprising a plurality of light emitting elements mounted on the array substrate, wherein the light emitting elements include a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer; an insulating layer disposed on the other side of the light emitting structure; a first electrode electrically connected to the first conductive semiconductor layer through the insulating layer; a second electrode electrically connected to the second conductive type semiconductor layer through the insulating layer; a first ohmic electrode electrically connected to the first conductive semiconductor layer; and a second ohmic electrode electrically connected to the second conductivity type semiconductor layer, wherein the active layer emits light in a red wavelength range, and the first conductivity type semiconductor layer has a first ohmic electrode in contact with the first ohmic electrode. An ohmic layer is included, and the first ohmic layer has a GaAs composition.

According to an embodiment, the red light emitting device may be implemented in a flip chip form.

In addition, a light emitting device having excellent light extraction efficiency can be manufactured.

In addition, a light emitting device having excellent ohmic contact can be manufactured.

Various advantageous advantages and effects of the present invention are not limited to the above description, and will be more easily understood in the process of describing specific embodiments of the present invention.

1 is a conceptual diagram of a light emitting device according to an embodiment of the present invention;
2a to 2i are various embodiments of a light emitting structure,
3A to 3E are various modified examples of the buffer layer inserted into the second conductivity type semiconductor layer;
4 is a conceptual diagram of a light emitting device according to another embodiment of the present invention;
5 to 9 are views showing a method of manufacturing a light emitting device according to an embodiment of the present invention,
10 to 13 are views showing a method of manufacturing a light emitting device according to another embodiment of the present invention.
14 is a conceptual diagram of a display device according to an embodiment of the present invention.

The present embodiments may be modified in other forms or combined with each other, and the scope of the present invention is not limited to each of the embodiments described below.

Even if a matter described in a specific embodiment is not described in another embodiment, it may be understood as a description related to another embodiment, unless there is a description contrary to or contradictory to the matter in another embodiment.

For example, if the characteristics of component A are described in a specific embodiment and the characteristics of component B are described in another embodiment, the opposite or contradictory description even if the embodiment in which components A and B are combined is not explicitly described. Unless there is, it should be understood as belonging to the scope of the present invention.

In the description of the embodiment, in the case where an element is described as being formed “on or under” of another element, on or under (on or under) or under) includes both elements formed by directly contacting each other or by indirectly placing one or more other elements between the two elements. In addition, when expressed as "on or under", it may include the meaning of not only the upward direction but also the downward direction based on one element.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention.

1 is a conceptual diagram of a light emitting device according to an embodiment of the present invention.

Referring to FIG. 1 , the light emitting device 100A penetrates the light emitting structure P1, the insulating layer 190 disposed on the other side P12 of the light emitting structure P1, and the insulating layer 190 to pass through the first conductive type. It includes a first electrode 182 electrically connected to the semiconductor layer 120 and a second electrode 181 electrically connected to the second conductive semiconductor layer 140 through the insulating layer 190 .

The light emitting structure P1 includes a first conductive semiconductor layer 120 , an active layer 130 , and a second conductive semiconductor layer 140 . The wavelength type of the light emitting structure P1 is not particularly limited. Hereinafter, light emitted from the light emitting structure P1 will be described as light in a red wavelength band.

The plurality of first ohmic electrodes 170 may pass through the insulating layer 190 and contact the first conductive type semiconductor layer 120 . The first ohmic layer 121 of the first conductivity-type semiconductor layer 120 may have a GaAs composition having a low energy band gap. Accordingly, contact resistance between the first conductive semiconductor layer 120 and the first ohmic electrode 170 may be reduced. Since the first ohmic layer 121 absorbs light in the red wavelength band, an area other than the area where the first ohmic electrode 170 is formed may be removed. The area of the first ohmic layer 121 may be 2% to 7% of the total area of the second conductive semiconductor layer 140 .

A reflective electrode layer 150 may be disposed on the first conductive semiconductor layer 120 . The reflective electrode layer 150 may entirely cover the first ohmic electrode 170 . The reflective electrode layer 150 may include a transparent electrode layer and a reflective layer.

The transparent electrode layer may be formed of a material having excellent electrical conductivity so that current injected from the outside can be evenly spread horizontally. The transparent electrode layer may be formed of a transparent conductive oxide (TCO). The transparent conductive oxide film is ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), AZO (Aluminum Zinc Oxide), AGZO (Aluminum Gallium Zinc Oxide), IZTO (Indium Zinc Tin Oxide), IAZO (Indium Aluminum Zinc Oxide), IGZO (Indium Gallium Zinc Oxide), IGTO (Indium Gallium Tin Oxide), ATO (Antimony Tin Oxide), GZO (Gallium Zinc Oxide), IZON (IZO Nitride), ZnO, IrOx, RuOx and NiO.

The reflective layer is formed of a material with high reflectivity, such as Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf, or a material with high reflectance and IZO, IZTO, IAZO, IGZO, or IGTO. , AZO, may be formed by mixing transparent conductive materials such as ATO.

The insulating layer 190 may be entirely disposed on the other side P12 of the light emitting structure P1. The insulating layer 190 may be formed by selecting at least one from the group consisting of SiO ₂ , SixOy, Si3N4, SixNy, SiOxNy, Al2O3, TiO2, AlN, and the like, but is not limited thereto. The insulating layer 190 may be formed as a single layer or multiple layers. Illustratively, the insulating layer 190 may also have a DBR structure made of Si oxide or a Ti compound.

The insulating layer 190 may be formed on the sidewall of the through hole formed in the light emitting structure P1 to electrically insulate the second electrode 181 from the active layer 130 .

The second ohmic electrode 160 may contact the second conductivity type semiconductor layer 140 . The second conductivity type semiconductor layer 140 contacting the second ohmic electrode 160 may have a GaP composition. Accordingly, contact resistance between the second conductive semiconductor layer 140 and the second ohmic electrode 160 may be reduced. A thickness d1 between the second ohmic electrode 160 and the first conductive semiconductor layer 20 may range from 150 nm to 4250 nm.

The first ohmic electrode 170 and the second ohmic electrode 160 are indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), and indium gallium oxide (IGZO). zinc oxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO Nitride), AGZO (Al-Ga ZnO), IGZO (In -Ga ZnO), ZnO, IrOx, RuOx, NiO, RuOx/ITO, Ni/IrOx/Au, or Ni/IrOx/Au/ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, It may be formed including at least one of In, Ru, Mg, Zn, Pt, Au, and Hf, but is not limited to these materials.

The optical layer 112 may be formed on one side P11 of the light emitting structure P1 to adhere the light transmitting substrate 111 and the light emitting structure P1. The optical layer 112 may be a resin such as polycarbonates (PC) or poly-methyl-methacrylate (PMMA), or may be an optical clear adhesive (OCA). The optical layer 112 is not particularly limited as long as it is made of a material that transmits visible light.

The light transmission substrate 111 may be an insulating substrate. The light transmitting substrate 111 may be formed of a material selected from sapphire (Al ₂ O ₃ ), SiC, GaN, ZnO, Si, GaP, InP, and Ge, but is not particularly limited as long as it transmits visible light.

The light transmitting substrate 111 may have a thickness of 100 um to 1000 um. Accordingly, light is emitted to the side of the light-transmissive substrate 111, and light extraction efficiency can be improved. A plurality of concavo-convex portions may be formed on the light-transmitting substrate 111 . The uneven portion may improve light extraction efficiency.

2a to 2i are various examples of light emitting structures, and FIGS. 3a to 3e are various modified examples of a buffer layer.

Referring to FIG. 2 , the light emitting structure P1 may include a first conductive semiconductor layer 120 , an active layer 130 , and a second conductive semiconductor layer 140 .

The first conductivity type semiconductor layer 120 may be implemented with at least one of group III-V and II-VI compound semiconductors doped with a first conductivity type dopant.

The first conductivity-type semiconductor layer 120 may be formed of, for example, a semiconductor material having a composition formula of InxAlyGa1-x-yP (0≤x≤1, 0≤y≤1, 0≤x+y≤1).

The first conductive semiconductor layer 120 may include, for example, at least one of AlGaInP, AlInP, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, and GaAsP.

The first conductive semiconductor layer 120 may be an n-type semiconductor layer doped with an n-type dopant such as Si, Ge, Sn, Se, or Te. The first conductive type semiconductor layer 120 may be disposed in a single layer or multiple layers.

The first conductive semiconductor layer 120 according to the embodiment may include a first cladding layer 123 , a first current diffusion layer 122 , and a first ohmic layer 121 .

The first cladding layer 123 may be an n-type carrier injection layer and may include AlInP. The concentration of Al may be 0.2 to 0.7. The thickness of the first cladding layer 123 may be 300 nm to 700 nm. The first cladding layer 123 may be a layer having the highest transmittance of light in the red wavelength band because the concentration of Al is relatively high. Doping concentration of the dopant may be 4.0×10 ¹⁷ /cm ³ to 6.0×10 ¹⁷ /cm ³ .

The first current spreading layer 122 serves to spread the current injected through the electrode. The first current spreading layer 122 may have a smaller energy bandgap than the first cladding layer 123 and a larger energy bandgap than the first ohmic layer 121 .

The first current spreading layer 122 may include AlGaInP. As the concentration of Al increases, the transmittance increases, but the resistance may also increase. The first current diffusion layer 122 has a lower Al concentration than the first cladding layer 123 and can serve as a low resistance layer. Doping concentration of the dopant may be 0.8.0×10 ¹⁸ /cm ³ to 1.2×10 ¹⁸ /cm ³ .

The thickness of the first current spreading layer 122 may be 2500 nm to 3000 nm. The surface of the first current diffusion layer 122 has irregularities to increase light extraction efficiency. The irregularities may be formed by dry etching.

The first ohmic layer 121 may include Ga (gallium) and As (arsenic), and may be doped with an n-type dopant such as Si, Ge, Sn, Se, or Te. The thickness of the first ohmic layer 121 may be about 20 nm to about 80 nm. Since the energy band gap of the first ohmic layer 121 is smaller than that of the first current spreading layer 122, ohmic contact with the electrode may be facilitated.

For example, the first ohmic layer 121 may have an energy band gap of 1.4 eV. The doping concentration of the dopant of the first ohmic layer 121 is 4.0×10 ¹⁸ /cm ³ to 6.0×10 ¹⁹ /cm ³ , which may be the highest in the first conductivity-type semiconductor layer 120 . Therefore, contact resistance with the ohmic electrode can be lowered.

However, it is not necessarily limited thereto, and the structure of the first conductivity type semiconductor layer 120 may be modified in various ways. Illustratively, as shown in FIG. 2B, the first conductivity-type semiconductor layer 120 may include a first cladding layer 123 and a first current diffusion layer 122, and as shown in FIG. 2D, the first ohmic layer 121 and a first clad layer 123.

The active layer 130 may be formed of at least one of a single well, a single quantum well, a multi-well, a multi-quantum well (MQW) structure, a quantum-wire structure, or a quantum dot structure. .

In the active layer 130, electrons (or holes) injected through the first conductive semiconductor layer 120 and holes (or electrons) injected through the second conductive semiconductor layer 140 meet each other, thereby forming the active layer 130. It is a layer that emits light by the band gap difference according to the forming material.

The active layer 130 may be implemented as a compound semiconductor. For example, the active layer 130 may be implemented with at least one of group II-VI and group III-V compound semiconductors.

Referring to FIG. 2E , the active layer 130 includes a plurality of well layers 131 and a plurality of barrier layers 132 alternately disposed, and the number of well layer 131/barrier layer 132 pairs is 2 to 100. It can be formed in 30 cycles. The period of the well layer 131/barrier layer 132 is, for example, AlInGaP/AlInGaP, InGaN/GaN, GaN/AlGaN, AlGaN/AlGaN, InGaN/AlGaN, InGaN/InGaN, AlGaAs/GaAs, InGaAs/GaAs, and at least one of InGaP/GaP, AlInGaP/InGaP, or InP/GaAs pairs.

The well layer 131 may be formed of a semiconductor material having a composition formula of InxAlyGa1-x-yP (0<x≤1, 0≤y≤1, 0≤x+y<1). The barrier layer 132 may be formed of a semiconductor material having a composition formula of InxAlyGa1-x-yP (0≤x≤1, 0≤y≤1, 0≤x+y<1).

The thickness of the well layer 131 may be about 5 nm to about 10 nm, and the thickness of the barrier layer 132 may be about 10 to 20 nm.

The active layer 130 may include outermost barrier layers 133a and 133b disposed adjacent to the first conductive semiconductor layer 120 and the second conductive semiconductor layer 140 . The outermost barrier layers 133a and 133b may have a composition of AlGaInP and may have a thickness of 40 nm to 60 nm.

The second conductivity-type semiconductor layer 140 may be formed of, for example, a semiconductor material having a composition formula of InxAlyGa1-x-yP (0≤x≤1, 0≤y≤1, 0≤x+y≤1).

The second conductive semiconductor layer 140 may include, for example, at least one of AlInP, GaP, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaAs, GaAsP, or AlGaInP, and Mg and The same p-type dopant can be a doped p-type semiconductor layer.

The second conductive type semiconductor layer 140 may be disposed in a single layer or multiple layers. The second conductivity-type semiconductor layer 140 may have a superlattice structure in which at least two different layers are alternately disposed.

The second conductive semiconductor layer 140 may include a second cladding layer 142 , a second current diffusion layer 148 , and a second ohmic layer 149 .

The second cladding layer 142 may be a P-type carrier injection layer and may include AlInP. The concentration of Al may be 0.2 to 0.7. The second clad layer 142 may have a thickness of 300 nm to 700 nm. Doping concentration of the dopant may be 1.0×10 ¹⁸ /cm ³ to 2.0×10 ¹⁸ /cm ³ .

The second current spreading layer 148 serves to spread the current injected through the electrode. The second current spreading layer 148 may have a smaller energy bandgap than the second cladding layer 142 and a larger energy bandgap than the second ohmic layer 149 . The second current spreading layer 148 may include GaP.

The second current spreading layer 148 may have a thickness of 3000 nm to 4000 nm. Doping concentration of the dopant may be 1.0×10 ¹⁸ /cm ³ to 2.0×10 ¹⁸ /cm ³ .

The second ohmic layer 149 may include GaP and may be doped with carbon. The second ohmic layer 149 may have a thickness of about 150 nm to about 250 nm. The doping concentration of carbon may be 5.0×10 ¹⁹ /cm ³ to 2.0×10 ²⁰ /cm ³ . The doping concentration of carbon is 5.0×10 ¹⁹ /cm ³ to 2.0×10 ²⁰ /cm ³ , ohmic contact with metal or ITO may be improved. The concentration of carbon may increase as the distance from the active layer 130 increases. However, it is not necessarily limited thereto, and carbon may not be doped.

Since the second current diffusion layer 148 has a thickness of 3000 nm to 4000 nm and the thickness of the second ohmic layer 149 has a thickness of 150 nm to 250 nm, the second conductivity type remains between the second ohmic electrode 160 and the optical layer 112. The thickness of the semiconductor layer 140 (d1 in FIG. 1 ) may be 150 nm to 4250 nm. When the thickness of the remaining second conductive semiconductor layer 140 (d1 in FIG. 1 ) is 250 nm or less, contact resistance may be lowered due to contact with the second ohmic layer 149 .

However, it is not necessarily limited thereto, and the structure of the second conductivity type semiconductor layer 140 may be modified in various ways. Illustratively, as shown in FIG. 2G , the second conductivity type semiconductor layer 140 may include a second cladding layer 142 and a second ohmic layer 148 . Alternatively, as shown in FIG. 2H, the second conductive semiconductor layer 140 may include a second cladding layer 142 and a second current diffusion layer 148, and the second current diffusion layer 148 may be doped with carbon.

Referring to FIG. 3A , a plurality of buffer layers may be disposed between the second clad layer 142 and the second current diffusion layer 148 .

The composition of the first buffer layer 143 may be AlGaInP, the thickness may be 150 nm to 250 nm, and the doping concentration of the dopant may be 1.0×10 ¹⁸ /cm ³ to 2.0×10 ¹⁸ /cm ³ . The second buffer layer 144 may have a composition of AlGaInP, a thickness of 10 nm to 15 nm, and a dopant concentration of 1.0×10 ¹⁸ /cm ³ to 2.0×10 ¹⁸ /cm ³ .

The first buffer layer 143 and the second buffer layer 144 can alleviate the energy bandgap difference between AlInP and GaP while gradually reducing the concentration of Al.

The composition of the third buffer layer 145 may be GaInP, the thickness may be 20 nm to 40 nm, and the doping concentration of the dopant may be 1.0×10 ¹⁸ /cm ³ to 2.0×10 ¹⁸ /cm ³ . The third buffer layer 145 can alleviate strain caused by a crystal lattice difference between AlGaP and GaP.

The fourth buffer layer 146 has a GaP composition, and the film quality of the second current diffusion layer 148 may be improved by controlling a growth rate and a growth temperature.

The thickness of the 4-1st buffer layer 146a may be 10 nm to 15 nm, the thickness of the 4-2 buffer layer 146b may be 40 nm to 60 nm, and the thickness of the 4-3 buffer layer 146c may be 60 nm to 80 nm. All of the doping concentrations of the 4-1st to 4-3rd buffer layers 146c may be 1.0×10 ¹⁸ /cm ³ to 2.0×10 ¹⁸ /cm ³ .

The second anti-diffusion layer 147 has a low doping concentration of 2.0×10 ¹⁷ /cm ³ to 3.0×10 ¹⁷ /cm ³ and can prevent diffusion of a dopant such as magnesium. The second diffusion barrier layer 147 may have a thickness of 150 nm to 250 nm.

A first diffusion barrier layer 141 may also be disposed between the active layer 130 and the second conductive semiconductor layer 140 . The first diffusion barrier layer 141 can prevent the dopant of the second conductive semiconductor layer 140 from diffusing into the active layer 130 . The composition of the first diffusion barrier layer 141 may be AlInP, and the thickness may be 200 nm to 300 nm.

However, it is not necessarily limited thereto, and the buffer layer disposed between the second conductive type semiconductor layers 140 may be variously modified as shown in FIGS. 3B to 3E.

4 is a conceptual diagram of a light emitting device according to another embodiment of the present invention.

Referring to FIG. 4 , in the light emitting device 100B according to the embodiment, the second ohmic electrode 163 may be entirely formed on the light emitting structure 163 . The second ohmic electrode 163 may be a transparent conductive oxide layer. The transparent conductive oxide film is ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), AZO (Aluminum Zinc Oxide), AGZO (Aluminum Gallium Zinc Oxide), IZTO (Indium Zinc Tin Oxide), IAZO (Indium Aluminum Zinc Oxide), IGZO (Indium Gallium Zinc Oxide), IGTO (Indium Gallium Tin Oxide), ATO (Antimony Tin Oxide), GZO (Gallium Zinc Oxide), IZON (IZO Nitride), ZnO, IrOx, RuOx and NiO.

The structure of the light emitting structure may be applied to both structures described in FIGS. 2 and 3 . Therefore, since the surface layer (the layer farthest from the active layer) of the second conductive semiconductor layer 140 contains carbon, ohmic contact efficiency with a transparent electrode such as ITO can be improved.

The second electrode 181 may pass through (181a) the light emitting structure P1 and be electrically connected to the second ohmic electrode 163 formed thereon.

According to the embodiment, since a transparent ohmic electrode is formed on the light emitting structure, it is possible to minimize light absorption while facilitating current distribution.

5 to 9 are views showing a method of manufacturing a light emitting device according to an embodiment of the present invention.

Referring to FIGS. 5 and 6 , an anti-etching layer 20 may be formed on the growth substrate 10 and the light emitting structure P1 may be grown thereon.

The growth substrate 10 may be a GaAs substrate. The thickness of the substrate may be 0.5 to 0.8 mm. An off-angle of the growth substrate 10 (an angle at which the wafer ingot is cut with respect to a flat surface) may be 15 degrees. When the off-angle is 15 degrees, the epi growth rate may be increased.

Thereafter, the growth substrate 10 is preheated and stress relieving layers 11 and 12 are formed. The stress relief layers 11 and 12 have a composition of GaAs and may have a thickness of 200 nm to 400 nm. An n-type dopant may be doped as needed.

Thereafter, an anti-etching layer 20 may be formed. The anti-etching layer 20 may have a composition of GaInP, and may be doped with an n dopant as needed. However, it is not necessarily limited thereto, and various P-based semiconductor layers (eg, InP, etc.) may be used as the etch stop layer. The anti-etching layer 20 may be formed to a thickness of about 100 nm to about 200 nm.

The first ohmic layer 121 may include GaAs and may be doped with an n-type dopant such as Si, Ge, Sn, Se, or Te. The thickness of the first ohmic layer 121 may be about 20 nm to about 50 nm. The first ohmic layer 121 has a smaller energy bandgap than the first current diffusion layer 122 , and ohmic contact may be facilitated. For example, the first ohmic layer 121 may have an energy band gap of 1.4 eV.

The first current spreading layer 122 serves to spread the current injected through the electrode. The first current spreading layer 122 may have a smaller energy bandgap than the first cladding layer 123 and a larger energy bandgap than the first ohmic layer 121 . The first current spreading layer 122 may include AlGaInP.

The thickness of the first current diffusion layer 122 may be manufactured to be 2500 nm to 3000 nm. Light extraction efficiency may be increased by forming irregularities on the surface of the first current diffusion layer 122 . The unevenness can be formed by dry etching.

The first cladding layer 123 may be an n-type carrier injection layer and may include AlInP. The concentration of Al may be 0.2 to 0.7. The thickness of the first cladding layer 123 may be 300 nm to 700 nm.

The active layer 130 may alternately form a plurality of well layers 131 and a plurality of barrier layers 132 . The number of each layer may be 20 pairs, but is not necessarily limited thereto.

The thickness of the well layer 131 may be about 5 nm to about 10 nm, and the thickness of the barrier layer 132 may be about 10 to 20 nm.

The active layer 130 may include outermost barrier layers 133a and 133b disposed adjacent to the first conductive semiconductor layer 120 and the second conductive semiconductor layer 140 .

A diffusion barrier layer 141 may be formed between the active layer 130 and the second conductive semiconductor layer 140 . The diffusion barrier layer 141 may prevent the dopant of the second conductive semiconductor layer 140 from diffusing into the active layer 130 .

The second conductivity-type semiconductor layer 140 may be formed of, for example, a semiconductor material having a composition formula of InxAlyGa1-x-yP (0≤x≤1, 0≤y≤1, 0≤x+y≤1).

The second cladding layer 142 may be a P-type carrier injection layer and may include AlInP. The concentration of Al may be 0.2 to 0.7. The second clad layer 142 may have a thickness of 300 nm to 700 nm. Doping concentration of the dopant may be 1.0×10 ¹⁸ /cm ³ to 2.0×10 ¹⁸ /cm ³ .

The second current spreading layer 148 serves to spread the current injected through the electrode. The second current spreading layer 148 may have a smaller energy bandgap than the second cladding layer 142 and a larger energy bandgap than the second ohmic layer 149 . The second current spreading layer 148 may include GaP.

The second current spreading layer 148 may have a thickness of 3000 nm to 4000 nm. Doping concentration of the dopant may be 1.0×10 ¹⁸ /cm ³ to 2.0×10 ¹⁸ /cm ³ .

The second ohmic layer 149 may include GaP and may be doped with carbon. The second ohmic layer 149 may have a thickness of about 150 nm to about 250 nm. The doping concentration of carbon may be 5.0×10 ¹⁹ /cm ³ to 2.0×10 ²⁰ /cm ³ . The doping concentration of carbon is 5.0×10 ¹⁹ /cm ³ to 2.0×10 ²⁰ /cm ³ , the ohmic contact with a metal or transparent electrode (eg, ITO) may be improved.

A plurality of buffer layers may be disposed between the second clad layer 142 and the second current diffusion layer 148 . The composition of the first buffer layer 143 may be AlGaInP, the thickness may be 150 nm to 250 nm, and the doping concentration of the dopant may be 1.0×10 ¹⁸ /cm ³ to 2.0×10 ¹⁸ /cm ³ . The second buffer layer 144 may have a composition of AlGaInP, a thickness of 10 nm to 15 nm, and a dopant concentration of 1.0×10 ¹⁸ /cm ³ to 2.0×10 ¹⁸ /cm ³ . The first buffer layer 143 and the second buffer layer 144 can alleviate the energy bandgap difference between AlInP and GaP.

The composition of the third buffer layer 145 may be GaInP, the thickness may be 20 nm to 40 nm, and the doping concentration of the dopant may be 1.0×10 ¹⁸ /cm ³ to 2.0×10 ¹⁸ /cm ³ . The third buffer layer 145 can alleviate stress due to a crystal lattice difference between AlGaP and GaP.

The fourth buffer layer 146 has a GaP composition, and the film quality of the second current diffusion layer 148 may be improved by controlling a growth rate and a growth temperature.

The thickness of the 4-1st buffer layer 146a may be 10 nm to 15 nm, the thickness of the 4-2 buffer layer 146b may be 40 nm to 60 nm, and the thickness of the 4-3 buffer layer 146c may be 60 nm to 80 nm. All of the doping concentrations of the 4-1st to 4-3rd buffer layers 146c may be 1.0×10 ¹⁸ /cm ³ to 2.0×10 ¹⁸ /cm ³ .

The anti-diffusion layer 147 is fabricated at a low doping concentration of 2.0×10 ¹⁷ /cm ³ to 3.0×10 ¹⁷ /cm ³ to prevent diffusion of a dopant such as magnesium. The thickness of the anti-diffusion layer 147 may be 150 nm to 250 nm.

Referring to FIG. 7 , an optical layer 112 and a light transmission substrate 111 may be formed. Specifically, after coating a resin such as PC, PMMA, or silicon on the light emitting structure P1, the light transmitting substrate 111 may be covered and cured thereon.

The light transmitting substrate 111 may be formed of a material selected from among sapphire (Al ₂ O ₃ ), SiC, GaN, ZnO, Si, GaP, InP, and Ge, and is not particularly limited as long as it transmits visible light.

Thereafter, the growth substrate 10 may be removed. What is the growth substrate 10? It can be removed using a wet-etching method. As the etching solution, various etching solutions capable of selectively removing GaAs may be selected. Illustratively, the etching solution may be an ammonia solution.

The etching solution can remove GaAs but does not etch GaInP. Therefore, the growth substrate 10 may be selectively removed using an etching solution. Thereafter, the anti-etching layer 20 may be removed. A method of removing the etch-stop layer 20 is not particularly limited. Illustratively, the anti-etching layer 20 may be removed using polishing.

Referring to FIG. 8 , after forming the first ohmic electrode 170 on the first ohmic layer 121 of the first conductivity-type semiconductor layer 120, the reflective electrode layer 150 may be formed thereon. At this time, since the first ohmic layer 121 is made of GaAs and absorbs red light, the region where the first ohmic electrode 170 is not formed can be deleted. Thereafter, the first through hole H1 is formed by etching the first conductive semiconductor layer 120 and the active layer 130 and the second ohmic electrode 160 is formed.

A reflective electrode layer 150 is formed on the second ohmic electrode 160, and an insulating layer 190 is formed thereon as a whole.

Then, as shown in FIG. 9, the first electrode 182 and the first conductive semiconductor layer 120 are electrically connected through the insulating layer 190, and the second electrode 181 is connected to the second conductive semiconductor layer ( 140) and can be electrically connected.

10 to 13 are views showing a method of manufacturing a light emitting device according to another embodiment of the present invention.

Referring to FIG. 10 , a second ohmic electrode 163 is formed on the light emitting structure P1. The second ohmic electrode 163 may be a transparent electrode such as ITO.

In this case, the surface layer of the second conductive semiconductor layer 140 may be doped with carbon. The doping concentration of carbon may be 5.0×10 ¹⁹ /cm ³ to 2.0×10 ²⁰ /cm ³ . When the doping concentration of carbon is 5.0×10 ¹⁹ /cm ³ to 2.0×10 ²⁰ /cm ³ , ohmic contact with a metal or a transparent electrode (eg, ITO) may be improved. Thereafter, as shown in FIG. 11 , an optical layer 112 and a light transmitting substrate 111 are formed.

Referring to FIG. 12 , a through hole H1 may be formed in the light emitting structure P1 to expose the second ohmic electrode 163 . Then, as shown in FIG. 13 , a second electrode 181 is formed and electrically connected to the second ohmic electrode 163 .

14 is a conceptual diagram of a display device according to an embodiment of the present invention.

Referring to FIG. 14 , the display device includes an array substrate 200 in which a plurality of common wires 241 and driving wires 242 intersect, and light emitting device packages 60 respectively disposed in a pixel area P. The panel 40, the first driver 32 for applying a driving signal to the common wiring 241, the second driver 31 for applying a driving signal to the driving wiring 242, and the first driver 20 2 may include a controller 50 that controls the driver 31 .

The array substrate 200 may be a circuit board on which the light emitting device package 60 is mounted. The array substrate 200 may be a single layer or multi-layer rigid substrate or a flexible substrate. A common wiring 241 and a driving wiring 242 may be formed on the array substrate 200 .

The pixel area P may be defined as an area where a plurality of common wires 241 and driving wires 242 intersect, and the pixel area P may include RGB sub-pixels. The light emitting device package 60 in which the first to third light emitting devices 100-1, 100-2, and 100-3 are disposed is mounted in the pixel area P, and may serve as an RGB sub-pixel. Hereinafter, three light emitting devices will be described as functioning as RGB sub-pixels, but the number of light emitting devices can be adjusted as needed.

The first light emitting device 100-1 may serve as a first subpixel outputting light in a blue wavelength range. The second light emitting device 100-2 may serve as a second subpixel outputting light in a green wavelength range. The third light emitting device 100-3 may serve as a third subpixel outputting light in a red wavelength range. All of the first to third light emitting devices 100A to 100C may be of a flip chip type.

The common wire 241 may be electrically connected to the light emitting elements disposed in the plurality of pixel regions P disposed in the first direction (X direction).

An electrical connection method between the common wire 241 and the light emitting devices 100A, 100B, and 100C is not limited. Illustratively, the common wire 241 and the light emitting element may be electrically connected using a through electrode or a lead electrode of a substrate.

The first to third driving wires 243 , 244 , and 245 may be electrically connected to light emitting elements disposed in a plurality of pixel regions P disposed in the second direction (Y direction).

The first driving wiring 243 is electrically connected to the first light emitting device 100-1, the second driving wiring 244 is electrically connected to the second light emitting device 100-2, and the third driving wiring may be electrically connected to the third light emitting device 100-3.

An electrical connection method between the driving wire 242 and the light emitting devices 100A, 100B, and 100C is not limited. Illustratively, the drive wire 242 and the light emitting element may be electrically connected using a through electrode or a lead electrode of a substrate.

The protective layer 47 may be disposed between the light emitting device packages 60 . The protective layer 47 may protect the circuit patterns of the light emitting device package 60 and the array substrate 200 .

The protective layer 47 may be formed of a material such as solder resist or an insulating material. The protective layer 47 may include at least one of SiO2, Si3N4, TiO2, Al2O3, and MgO.

The protective layer 47 may include a black matrix material. When the protective layer 47 is made of a black matrix material, it may be made of, for example, carbon black, graphite, or polypyrrole.

The controller 50 outputs a control signal to the first and second drivers 20 and 30 so that power is selectively applied to the common wire 241 and the first to third drive wires 243, 244 and 245, The first to third light emitting devices 100-1, 100-2, and 100-3 in the pixel P may be individually controlled.

The display device has SD (Standard Definition) resolution (760 × 480), HD (High definition) resolution (1180 × 720), FHD (Full HD) resolution (1920 × 1080), UH (Ultra HD) resolution ( 3480×2160), or UHD-level or higher resolution (eg, 4K (K=1000), 8K, etc.). In this case, the first to third light emitting devices 100-1, 100-2, and 100-3 according to the embodiment may be arranged and connected in plurality according to the resolution.

The display device may be an electronic display board or TV having a diagonal size of 100 inches or more, and pixels may be implemented as light emitting diodes (LEDs). Therefore, it can be provided with low power consumption, low maintenance cost, long lifespan, and a high-brightness self-luminous display.

Since the embodiment implements videos and images using the light emitting device package 60, it has excellent advantages in color purity and color reproduction.

Since the embodiment implements videos and images using a light emitting device package having excellent linearity, a clear large display of 100 inches or more can be implemented.

The embodiment can implement a large display device of 100 inches or more with high resolution at low cost.

The light emitting device package 60 according to the embodiment may be applied not only to the display device but also to a lighting unit, an indicator device, a lamp, a street light, a vehicle lighting device, a vehicle display device, and a smart watch, but is not limited thereto.

Claims (15)

A light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer;
an insulating layer disposed on the other side of the light emitting structure;
a first electrode electrically connected to the first conductive semiconductor layer through the insulating layer;
a second electrode electrically connected to the second conductive type semiconductor layer through the insulating layer;
a first ohmic electrode electrically connected to the first conductive semiconductor layer; and
A second ohmic electrode electrically connected to the second conductive semiconductor layer;
The active layer emits light in a red wavelength range,
The first conductivity-type semiconductor layer includes a first ohmic layer in contact with the first ohmic electrode, and the first ohmic layer has a GaAs composition;
A reflective electrode layer is disposed on the first conductivity type semiconductor layer,
The reflective electrode layer covers upper and side surfaces of the first ohmic electrode,
The reflective electrode layer includes a transparent electrode layer and a reflective layer.
According to claim 1,
The first conductive semiconductor layer includes a first cladding layer, a first current spreading layer, and a first ohmic layer contacting the first ohmic electrode;
The first current diffusion layer has a smaller energy band gap than the first cladding layer and a larger energy band gap than the first ohmic layer.
According to claim 2,
The first cladding layer and the first current diffusion layer include Al, In, and P,
The first ohmic layer has the highest doping concentration in the first conductivity type semiconductor layer.
According to claim 1,
The second conductive semiconductor layer includes a second cladding layer, a second current diffusion layer, and a second ohmic layer,
The second cladding layer includes Al, In, and P,
The second current diffusion layer and the second ohmic layer include Ga and P.
According to claim 4,
The second ohmic layer includes carbon,
The carbon concentration is 5×10 ¹⁹ /cm ³ to 2×10 ²⁰ /cm ³ Light emitting device. delete delete delete delete delete delete delete delete delete delete

Images