KR20140099687A

KR20140099687A - Light emitting device

Info

Publication number: KR20140099687A
Application number: KR1020130012405A
Authority: KR
Inventors: 최원희; 조현민
Original assignee: 엘지이노텍 주식회사
Priority date: 2013-02-04
Filing date: 2013-02-04
Publication date: 2014-08-13

Abstract

A light emitting device according to an embodiment of the present invention is configured to comprise: a first semiconductor layer; an electron blocking layer disposed on the first semiconductor layer; a strain reducing layer disposed on the electron blocking layer to reduce strain generated in the semiconductor layer; an active layer on the strain reducing layer; and a light emitting structure including the second semiconductor layer on the active layer, wherein the electron blocking layer contains InGaN, the strain reducing layer includes at least two pairs of an InGaN layer and a GaN layer which are alternatively stacked thereon, and the content ratio of In of the electron blocking layer is greater than the content ratio of In in the InGaN layer of the strain reducing layer.

Description

[0001]

An embodiment relates to a light emitting element.

As a typical example of a light emitting device, a light emitting diode (LED) is a device for converting an electric signal into an infrared ray, a visible ray, or a light using the characteristics of a compound semiconductor, and is used for various devices such as household appliances, remote controllers, Automation equipment, and the like, and the use area of LEDs is gradually widening.

In general, miniaturized LEDs are made of a surface mounting device for mounting directly on a PCB (Printed Circuit Board) substrate, and an LED lamp used as a display device is also being developed as a surface mounting device type . Such a surface mount device can replace a conventional simple lighting lamp, which is used for a lighting indicator for various colors, a character indicator, an image indicator, and the like.

As the use area of the LED is widened as described above, it is important to increase the luminance of the LED as the brightness required for a lamp used in daily life and a lamp for a structural signal is increased.

In addition, the electrode of the light emitting device should have excellent adhesive force and excellent electrical characteristics.

Further, research is underway to improve the probability of recombination of electrons and holes in the active layer of the light emitting device.

There is a problem that lattice mismatching of the semiconductor layer occurs due to different lattice constants between materials.

Embodiments provide a light emitting device that prevents electrons from overflowing, improves the efficiency of the light emitting device, and improves the quality of the light emitting structure.

A light emitting device according to an embodiment includes a first semiconductor layer, an electron blocking layer disposed on the first semiconductor layer, a strain relief layer disposed on the electron blocking layer to relax a strain generated in the semiconductor layer, And a second semiconductor layer on the active layer, wherein the electron blocking layer comprises InGaN, and the strain relief layer includes at least two pairs of InGaN and GaN layers, And the In content ratio of the electron blocking layer is larger than the In content ratio of the InGaN layer of the strain relaxation layer.

According to the embodiment, the strain relieving layer has an advantage of relieving strain generated between the first semiconductor layer and the active layer due to different lattice constants between the materials.

In addition, the embodiment does not change the strain abruptly in the strain relief layer, but layers having tensile and compressive strains are laminated alternately first thinly and then later thickly alternately to gradually change the strain , The strain between the active layer and the first semiconductor layer can be relaxed.

In addition, in the embodiment, the layers having tensile and compressive strains are laminated at first on a thin alternating basis, and then laminated in the same manner as the thicknesses of the barrier layers or the well layers to form an environment similar to the active layer in advance, And the strain generated between the active layer and the active layer can be relaxed.

In addition, the embodiment relaxes the lattice mismatch occurring in the semiconductor layer, and thus has the advantage of improving the quality of the semiconductor layer.

Further, in the embodiment, the energy band gap of the electron blocking layer is formed to be larger than the energy band gap of the strain relaxing layer, thereby blocking the electrons that overflow. This improves the probability of bonding of electrons and holes in the active layer, and thus has an advantage of improving the luminous efficiency of the light emitting device.

1 is a cross-sectional view illustrating a light emitting device according to an embodiment,
FIG. 2 is an enlarged sectional view of a portion A of the light emitting device of FIG. 1,
3 is an energy band diagram of a light emitting device according to an embodiment,
4 is a cross-sectional view illustrating a light emitting device according to another embodiment,
5 is a perspective view of a light emitting device package including a light emitting device according to an embodiment,
6 is a sectional view of a light emitting device package including a light emitting device according to an embodiment,
7 is an exploded perspective view of a display device having a light emitting device according to an embodiment.
8 is a view showing a display device having a light emitting device according to an embodiment.
9 is an exploded perspective view of a lighting device having a light emitting device according to an embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element. Thus, the exemplary term "below" can include both downward and upward directions. The elements can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size and area of each component do not entirely reflect actual size or area.

Further, the angle and direction mentioned in the description of the structure of the light emitting device in the embodiment are based on those shown in the drawings. In the description of the structure of the light emitting device in the specification, reference points and positional relationship with respect to angles are not explicitly referred to, refer to the related drawings.

FIG. 1 is a cross-sectional view showing a light emitting device according to an embodiment, FIG. 2 is an enlarged sectional view of a light emitting device of FIG. 1, and FIG. 3 is an energy band diagram of a light emitting device according to an embodiment.

Referring to FIG. 1, a light emitting device 100 according to an embodiment includes a first semiconductor layer 120, an electron blocking layer 125 on the first semiconductor layer 120, A strain relieving layer 140 that relaxes strain generated in the active layer 130 and a light emitting structure 140 that includes the active layer 130 on the strain relieving layer 140 and the second semiconductor layer 150 on the active layer 130 160 < / RTI >

1, the light emitting device 100 may include a substrate 110 and a light emitting structure 160 disposed on the substrate 110. The light emitting structure 160 may include a first semiconductor layer 120, An electron blocking layer 125, a strain relief layer 140, an active layer 130, and a second semiconductor layer 150.

The substrate 110 may be formed of any material having optical transparency, for example, sapphire (Al ₂ O ₃ ), GaN, ZnO, or AlO. However, the present invention is not limited thereto. Further, it can be a SiC supporting member having a higher thermal conductivity than a sapphire (Al ₂ O ₃ ) supporting member. However, it is preferable that the refractive index of the substrate 110 is smaller than the refractive index of the first semiconductor layer 120 for light extraction efficiency.

On the other hand, a PSS (Patterned SubStrate) structure may be provided on the upper surface of the substrate 110 to enhance light extraction efficiency. The support member 110 referred to herein may or may not have a PSS structure.

A buffer layer (not shown) may be disposed on the substrate 110 to mitigate lattice mismatch between the substrate 110 and the first semiconductor layer 120 and to facilitate growth of the semiconductor layer. The buffer layer (not shown) can be formed in a low-temperature atmosphere and can be made of a material that can alleviate the difference in lattice constant between the semiconductor layer and the supporting member. For example, materials such as GaN, InN, AlN, AlInN, InGaN, AlGaN, and InAlGaN can be selected and not limited thereto.

A buffer layer (not shown) may be grown on the substrate 110 as a single crystal, and a buffer layer (not shown) grown by a single crystal may improve the crystallinity of the first semiconductor layer 120 grown on the buffer layer have.

On the buffer layer (not shown), the undoped semiconductor layer 115 may be located. The undoped semiconductor layer 115 is a nitride semiconductor layer which does not intentionally implant n-type impurity but has an n-type conductivity. For example, the undoped semiconductor layer 115 may be formed of Undoped-GaN It is possible.

The light emitting structure 160 including the first semiconductor layer 120, the strain relaxation layer 140, the active layer 130, and the second semiconductor layer 150 may be formed on the unshown semiconductor layer 115.

The first semiconductor layer 120 may be located on the un-oxidized semiconductor layer 115. The first semiconductor layer 120 may be formed of an n-type semiconductor layer and may provide electrons to the active layer 130. The first semiconductor layer 120 may be a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? _Y? 1, 0? _X + y? For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, and AlInN, and n-type dopants such as Si, Ge, and Sn may be doped.

An electron blocking layer 125 is disposed on the first semiconductor layer 120. A detailed description of the electron blocking layer 125 will be described later.

A strain relief layer 140 may be formed on the electron blocking layer 125.

The strain relief layer 140 may have a supper lattice structure to mitigate the strain generated in the light emitting structure 160.

That is, the strain relieving layer 140 relaxes strain generated between the first semiconductor layer 120 and the active layer 130 due to lattice constants having different lattice constants between the materials, and the first semiconductor layer 120 The injected electrons are blocked to prevent electron overflow phenomenon.

The active layer 130 may be formed on the strain relief layer 140. The active layer 130 may be formed of a single or multiple quantum well structure, a quantum-wire structure, a quantum dot structure, or the like using a compound semiconductor material of Group 3-V group elements.

When the active layer 130 is formed of a quantum well structure, for example, a well layer having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? Y? 1, 0? X + y? 1) And a barrier layer having a composition formula of In _a Al _b Ga _1-ab N (0? A? ₁ , 0? B? ₁ , 0? A + b? 1). The well layer may be formed of a material having a band gap smaller than the band gap of the barrier layer.

A conductive clad layer (not shown) may be formed on and / or below the active layer 130. The conductive clad layer (not shown) may be formed of an AlGaN-based semiconductor and may have a band gap larger than that of the active layer 130.

The second semiconductor layer 150 may be implemented as a p-type semiconductor layer to inject holes into the active layer 130. The second semiconductor layer 150 may be a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? _Y? 1, 0? _X + y? For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN and AlInN, and a p-type dopant such as Mg, Zn, Ca, Sr and Ba may be doped.

A current blocking layer (not shown) may be formed between the active layer 130 and the second semiconductor layer 150, and electrons injected from the first semiconductor layer 120 into the active layer 130 May be an electron blocking layer for preventing the second semiconductor layer 150 from being recombined in the active layer 130 and flowing to the second semiconductor layer 150. The current blocking layer has a band gap relatively larger than that of the active layer 130 so that electrons injected from the first semiconductor layer 130 are injected into the second semiconductor layer 150 without being recombined in the active layer 130 . Accordingly, it is possible to increase the probability of recombination of electrons and holes in the active layer 140 and to prevent a leakage current.

On the other hand, the current blocking layer may have a band gap larger than the band gap of the barrier layer included in the active layer 130, and may be formed of a semiconductor layer containing Al, such as p-type AlGaN, but is not limited thereto.

The first semiconductor layer 120, the active layer 130, and the second semiconductor layer 150 may be formed using a metal organic chemical vapor deposition (MOCVD) method, a chemical vapor deposition (CVD) method, ), A plasma enhanced chemical vapor deposition (PECVD) method, a molecular beam epitaxy (MBE) method, a hydride vapor phase epitaxy (HVPE) method, or a sputtering method The present invention is not limited thereto.

In addition, the doping concentrations of the conductive dopants in the first semiconductor layer 120 and the second semiconductor layer 150 can be uniformly or nonuniformly formed. That is, the plurality of semiconductor layers may be formed to have various doping concentration distributions, but the invention is not limited thereto.

The first semiconductor layer 120 may be a p-type semiconductor layer, the second semiconductor layer 150 may be an n-type semiconductor layer, and an n-type or p-type semiconductor may be formed on the second semiconductor layer 150. [ A third semiconductor layer (not shown) may be formed. Accordingly, the light emitting device 100 may have at least one of np, pn, npn, and pnp junction structures.

A part of the first semiconductor layer 120 may be exposed and the first electrode 174 may be formed on the exposed first semiconductor layer 120. In this case, Can be formed. That is, the first semiconductor layer 120 includes an upper surface facing the active layer 130 and a lower surface facing the substrate 110, and an upper surface including a region exposed at least one region, As shown in FIG.

Meanwhile, a method of exposing a part of the first semiconductor layer 120 may use a predetermined etching method, but is not limited thereto. The etching method may be a wet etching method or a dry etching method.

A transparent electrode layer 180 may be formed on the second semiconductor layer 150. The transparent electrode layer 170 plays a role of uniformly spreading current to the second semiconductor layer 150.

The transparent electrode layer 180 may be formed of, for example, ITO, IZO (In - ZnO), GZO (Ga - ZnO), AZO (Al - ZnO), AGZO , RuOx, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO.

A second electrode 172 may be formed on the transparent electrode layer 180.

The first and second electrodes 172 and 174 may be formed of a conductive material such as In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, And may include metals selected from Ti, Ag, Cr, Mo, Nb, Al, Ni, Cu, and Ti, or an alloy thereof and may be formed as a single layer or a multilayer .

The strain relieving layer 140 may be formed by alternately stacking at least two pairs of InGaN layers 141A, 143A and 145A and GaN layers 141B, 143B and 145B.

Preferably, referring to FIG. 2, the strain relief layer 140 may include at least two subgroups. In FIG. 2, three subgroups 141, 143, and 145 are shown, but the present invention is not limited thereto. Here, the first sub-group 141 and the second sub-group 143 and 145 are defined as the first sub-group 141, the second sub-group 143 and the fourth sub-group 145 in the direction of the active layer 130, .

The number of subgroups 141, 143, and 145 is not limited, but may have 2 to 8 subgroups.

On the other hand, the subgroups 141, 143, and 145 may be formed by alternately stacking at least two pairs of InGaN layers and GaN layers. More preferably three pairs to eight pairs can be alternately stacked.

The thickness of each of the subgroups 141, 143, and 145 may be thicker toward the active layer 130. The thickness of each of the subgroups 141, 143 and 145 becomes thicker toward the active layer 130 and becomes closer to the active layer 130 so that the active layer 130 has a structure similar to that of the active layer 130, ), The lattice constant of the strain relieving layer 140 becomes similar to that of the active layer 130, and strain can be reduced.

The arrangement in which the thickness of each of the subgroups 141, 143, and 145 becomes thicker toward the active layer 130 may have various arrangements.

For example, the thickness of the second subgroup 143 may be thicker than the thickness of the first subgroup 141, and the thickness of the third subgroup 145 may be thicker than the thickness of the second subgroup 143.

The number of the InGaN layers 141A, 143A, and 145A and the number of the GaN layers 141B, 143B, and 145B in the subgroups 141, 143, and 145 are the same. For example, the number of InGaN layers 141A in the first subgroup 141 and the number of InGaN layers 143A and 145A in the second subgroup 143 and the third subgroup 145 are set to be the same And the number of the GaN layers 141B in the first subgroup 141 and the number of the GaN layers 143B and 145B in the second subgroup 143 and the third subgroup 145 are the same. It is preferable that the thicknesses of the InGaN layers 141A, 143A, 145A and the GaN layers 141B, 143B, 145B are uniformly arranged in the subgroups 141, 143, 145. That is, the thicknesses of the InGaN layers 141A, 143A, and 145A and the GaN layers 141B, 143B, and 145B may be different if the subgroups 141, 143, and 145 are different.

The thicknesses of the InGaN layers 141A, 143A and 145A and the GaN layers 141B, 143B and 145B may be 1 nm to 1 nm and the thicknesses of the GaN layers 141B, 143B and 145B may be InGaN layers 141A, Or greater than the thickness of < / RTI >

Another example of the arrangement in which the thickness of each of the subgroups 141, 143, and 145 becomes thicker toward the active layer 130 is as follows. However, the above description is premised.

For example, the thickness of the InGaN layer in the subgroup adjacent to the active layer 130 may be greater than the thickness of the InGaN layer in the subgroup adjacent to the first semiconductor layer 120. That is, the thickness of the InGaN layer 143A in the second subgroup 143 may be greater than the thickness of the InGaN layer 141A in the first subgroup 141, and the thickness of the InGaN layer 145A May be thicker than the thickness of the InGaN layer 143A in the second subgroup 143. [ In other words, the thickness of the InGaN layers 141A, 143A, and 145A can be thicker as the subgroups 141, 143, and 145 are adjacent to the active layer 130. [ At this time, the GaN layers 141B, 143B and 145B of the subgroups 141, 143 and 145 are constant in thickness or formed thicker in the GaN layers 141B, 143B and 145B of the subgroups 141, 143 and 145 adjacent to the active layer 130 .

At this time, it is preferable that the thickness of the InGaN layers 141A, 143A and 145A is a thickness of the barrier layer or the well layer of the active layer 130. [ That is, the thickness of the InGaN layer of the third sub-group 145 adjacent to the active layer 130 may be the same as the barrier layer or the well layer of the active layer 130. That is, the thickness of the InGaN layers 141A, 143A, and 145A is initially set to be thin, and finally the thickness of the InGaN layers 141A, 143A, and 145A is set to be similar to the thicknesses of the barrier layer and the well layer of the active layer 130, It is possible to alleviate the strain generated in the substrate.

As another example, the thickness of the GaN layer in the subgroup adjacent to the active layer 130 may be greater than the thickness of the GaN layer in the subgroup adjacent to the first semiconductor layer 120. That is, the thickness of the GaN layer 143B in the second subgroup 143 may be greater than the thickness of the GaN layer 141B in the first subgroup 141, and the thickness of the GaN layer 145B May be thicker than the thickness of the GaN layer 143B in the second subgroup 143. [ The thickness of the GaN layers 141B, 143B, and 145B may be thicker as the subgroups 141, 143, and 145 are adjacent to the active layer 130. [ At this time, the InGaN layers 141A, 143A, and 145A of the subgroups 141, 143, and 145 are constant in thickness or formed thicker in the InGaN layers 141A, 143A, and 145A of the subgroups 141, 143 and 145 adjacent to the active layer 130 .

At this time, it is preferable that the thickness of the GaN layers 141B, 143B, 145B is limited to the thickness of the barrier layer or the well layer of the active layer 130. That is, the thickness of the GaN layer of the third sub-group 145 adjacent to the active layer 130 may be the same as the barrier layer or the well layer of the active layer 130. That is, the thickness of the GaN layers 141B, 143B, and 145B is initially set to be thin, and finally, the thicknesses of the barrier layer and the well layer of the active layer 130 are set to be close to each other between the first semiconductor layer 120 and the active layer 130 It is possible to alleviate the strain generated in the substrate.

Here, the same meaning does not mean that the mathematical meaning is completely equal, but means the same in a range including an error.

The thicknesses of the InGaN layer and the GaN layer of the subgroups 141, 143 and 145 increase as they are adjacent to the active layer 130 and become similar to the thicknesses of the barrier layer or the well layer of the active layer 130, (130).

The embodiment is not to change the strain abruptly in the strain relieving layer 140 but rather to alternately laminate the layers having tensile and compressive strains alternately first thinly and then thickly alternately and gradually changing the strain The strain between the active layer 130 and the first semiconductor layer 120 can be relaxed.

In addition, in the embodiment, since layers having tensile and compressive strains are laminated at first on a thin and alternate basis, and then laminated in the same manner as the thicknesses of the barrier layer and the well layer to form an environment similar to the active layer 130 in advance The strain generated between one semiconductor layer 120 and the active layer 130 can be relaxed.

The In content ratio (concentration) of the InGaN layers 141A, 143A and 145A can be made higher as the InGaN layers 141A, 143A and 145A of the subgroups 141, 143 and 145 adjacent to the active layer 130 are.

The In content ratio of the InGaN layers 141A, 143A, and 145A may be smaller than the In content ratio of the electron blocking layer 125. [ For example, the In content ratio of the InGaN layers 141A, 143A, and 145A may be 1% to 10%. However, the present invention is not limited thereto.

The energy band gap of the electron blocking layer 125 is formed to be larger than the energy band gap of the strain relief layer 140, thereby blocking the electrons that overflow. This improves the probability of bonding of electrons and holes in the active layer 130, so that the luminous efficiency of the light emitting device is improved.

The electron blocking layer 125 may be made of various materials, but may include InGaN. At this time, the In content (ratio) of the electron blocking layer 125 may be larger than the In content (ratio) of the strain relaxation layer 140. For example, the In content ratio of the electron blocking layer 125 may be 10% to 25%. When the In content ratio of the electron blocking layer 125 is less than 10%, the piezoelectric polarization phenomenon occurring between the electron blocking layer 125 and the strain relaxing layer 140 hardly occurs and the first semiconductor layer The electron blocking layer 125 can not effectively block the electrons injected into the electron blocking layer 125. When the In content ratio of the electron blocking layer 125 is larger than 25%, the quality of the electron blocking layer 125 is deteriorated. ) And the electron blocking layer 125 are largely generated.

The electron blocking layer 125 is disposed in contact with the strain relief layer 140. The In content ratio of the electron blocking layer 125 is set to be in contact with the InGaN layer 141A or the GaN layer 141B of the electron blocking layer 125 or the strain relieving layer 140, Is less than when the electron blocking layer 125 is in contact with the InGaN layer 141A at the time of bonding with the GaN layer 141B.

The thickness of the electron blocking layer 125 is not limited, but may be thicker than the thickness of the InGaN layers 141A, 143A, and 145A and the GaN layers 141B, 143B, and 145B. This is to effectively block the electrons supplied to the first semiconductor layer 120. Is sufficient between the electron blocking layer 125 and the strain relieving layer 140 to provide a sufficient piezoelectric field for blocking electrons. More preferably, the thickness of the electron blocking layer 125 may be between 1 nm and 10 nm.

Referring to FIG. 3, the advantages of the embodiment will be described as follows.

Piezoelectric polarizations may occur in the semiconductor layer due to the stress caused by the difference in lattice constant and the orientation between the semiconductor layers. Since the semiconductor material forming the light emitting element has a large value of the piezoelectric coefficient, it can cause a very large polarization even with a small strain. The electric field induced by the two polarization changes the energy band structure of the quantum well structure, distorting the distribution of electrons and holes. This effect is called the quantum confined stark effect (QCSE).

An electric field induced by the above-described polarization is formed between the electron blocking layer 125 and the strain relaxing layer 140 of the embodiment to block a part of electrons supplied to the first semiconductor layer 120 . Therefore, this improves the luminous efficiency. That is, the embodiment can prevent the electrons injected from the second semiconductor layer 150 from being injected into the first semiconductor layer 120 without being recombined in the active layer 250.

The lattice mismatch caused by the electron blocking layer 125 can be solved by disposing the strain relief layer 140 as described above. Therefore, the quality of the light emitting device can be improved.

4 is a cross-sectional view illustrating a light emitting device according to another embodiment.

Referring to FIG. 4, the light emitting device 200 according to the embodiment includes a support member 210, a first electrode layer 215 disposed on the support member 210, a second electrode layer 215 on the first electrode layer 215, An active layer 230 on the first semiconductor layer 250, a strain relief layer 240 on the active layer 230, an electron blocking layer 225 on the strain relief layer 240, A first semiconductor layer 220, and a second electrode layer 282 on the first and second electrodes 225 and 225.

The support member 210 may be formed using a material having a high thermal conductivity, or may be formed of a conductive material. The support member 210 may be formed using a metal material or a conductive ceramic. The support member 210 may be formed as a single layer, and may be formed as a double structure or a multiple structure.

That is, the support member 210 may be formed of any one selected from a metal, for example, Au, Ni, W, Mo, Cu, Al, Ta, Ag, Pt, and Cr, or may be formed of two or more alloys. The above materials can be laminated. In addition, the support member 210 may be implemented with a carrier wafer such as Si, Ge, GaAs, ZnO, SiC, SiGe, GaN, Ga 2 O 3.

Such a support member 210 facilitates the release of heat generated in the light emitting device 200, thereby improving the thermal stability of the light emitting device 200.

A first electrode layer 215 may be formed on the support member 210. The first electrode layer 215 may include an ohmic layer (not shown), a reflective layer (not shown) and a bonding layer (not shown). For example, the first electrode layer 215 may be a structure of an ohmic layer / a reflection layer / a bonding layer, a laminate structure of an ohmic / reflective layer, or a structure of a reflection layer (including ohmic) / bonding layer. For example, the first electrode layer 215 may be formed by sequentially stacking a reflective layer and an ohmic layer on an insulating layer.

The reflective layer (not shown) may be disposed between an ohmic layer (not shown) and an insulating layer (not shown), and may be formed of a material having excellent reflection characteristics, such as Ag, Ni, Al, Rh, Pd, , Zn, Pt, Au, Hf, and combinations thereof. Alternatively, the metal material and the transparent conductive material such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, . Further, the reflective layer (not shown) can be laminated with IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni and the like. When a reflective layer (not shown) is formed of a material that makes an ohmic contact with the light emitting structure 260 (for example, the second semiconductor layer 250), an ohmic layer (not shown) may not be formed separately, I do not.

The ohmic layer (not shown) is in ohmic contact with the lower surface of the light emitting structure 260, and may be formed in a layer or a plurality of patterns. The ohmic layer (not shown) may be formed of a transparent electrode layer and a metal. For example, ITO (indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tin oxide) ), IGZO (indium gallium zinc oxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IrO _x , RuO _x , RuO _x / Ni, Ag, Ni / IrO _x / Au, and Ni / IrO _x / Au / ITO. The ohmic layer (not shown) is provided for smoothly injecting carriers into the second semiconductor layer 250, and is not necessarily formed.

The first electrode layer 215 may include a bonding layer (not shown), wherein the bonding layer (not shown) may include a barrier metal or a bonding metal such as Ti, Au, Sn, Ni , Cr, Ga, In, Bi, Cu, Ag, or Ta.

The light emitting structure 260 may include at least a first semiconductor layer 220, an active layer 230 and a second semiconductor layer 250 and may be formed between the first semiconductor layer 220 and the second semiconductor layer 250 And the active layer 230 may be disposed.

A second semiconductor layer 250 may be formed on the first electrode layer 215. The second semiconductor layer 250 may be a p-type semiconductor layer doped with a p-type dopant. The p-type semiconductor layer is a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? Y? 1, 0? X + y? 1) AlGaN, InGaN, InN, InAlGaN, AlInN and the like, and a p-type dopant such as Mg, Zn, Ca, Sr and Ba may be doped.

The active layer 230 may be formed on the second semiconductor layer 250. The active layer 230 may be formed of a single or multiple quantum well structure, a quantum-wire structure, a quantum dot structure, or the like using a compound semiconductor material of Group 3-V group elements.

When the active layer 230 is formed of a quantum well structure, for example, a well layer having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? Y? 1, 0? X + y? 1) And a barrier layer having a composition formula of In _a Al _b Ga _1-ab N (0? A? ₁ , 0? B? ₁ , 0? A + b? 1). The well layer may be formed of a material having a band gap smaller than the band gap of the barrier layer.

A conductive clad layer (not shown) may be formed on and / or below the active layer 230. The conductive clad layer (not shown) may be formed of an AlGaN-based semiconductor and may have a band gap larger than that of the active layer 230.

A strain relief layer 240 is formed on the active layer 230. The structure of the strain relief layer 240 is the same as that described with reference to FIG. 2, and is different from FIG.

On the strain relief layer 240, an electron blocking layer 225 is formed. The electron blocking layer 225 is a layer for blocking electrons and the description thereof is the same as that described in the embodiment of FIG.

The first semiconductor layer 220 may be formed on the electron blocking layer 225. The first semiconductor layer 220 may be formed of an n-type semiconductor layer, and the n-type semiconductor layer may include, for example, In _x Al _y Ga _1-xy N (0? X? 1, 0? Y? for example, Si, Ge, Sn, Se, Te, or the like can be selected from a semiconductor material having a composition formula of Si, Ge, Sn, Type dopant can be doped.

A second electrode layer 282 electrically connected to the first semiconductor layer 220 may be formed on the first semiconductor layer 220. The second electrode layer 282 may include at least one pad or / . &Lt; / RTI > The second electrode layer 282 may be disposed in a center region, an outer region, or an edge region of the upper surface of the first semiconductor layer 220, but the present invention is not limited thereto. The second electrode layer 282 may be disposed in a region other than the first semiconductor layer 220, but the present invention is not limited thereto.

The second electrode layer 282 may be formed of a conductive material such as In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, W, , Mo, Nb, Al, Ni, Cu, and WTi.

A light extracting structure 284 may be formed on the upper portion of the light emitting structure 260.

The light extracting structure 270 may be formed on the upper surface of the first semiconductor layer 220 or may be formed on a transparent electrode layer (not shown) after forming a transparent electrode layer (not shown) on the light emitting structure 260 But not limited to,

The light extracting structure 284 may be formed in a light transmitting electrode layer (not shown), or a part or all of the upper surface of the first semiconductor layer 220. The light extracting structure 284 may be formed by performing etching on at least one region of the light transmitting electrode layer (not shown) or the top surface of the first semiconductor layer 220, but is not limited thereto. The etching process includes a wet etching process and / or a dry etching process. As the etching process is performed, the upper surface of the light transmitting electrode layer (not shown) or the upper surface of the first semiconductor layer 220 forms the light extracting structure 284 And may include roughness. The roughness may be irregularly formed in a random size, but is not limited thereto. The roughness may be at least one of a texture pattern, a concave-convex pattern, and an uneven pattern, which is an uneven surface.

The roughness may be formed to have various shapes such as a cylinder, a polygonal column, a cone, a polygonal pyramid, a truncated cone, a polygonal pyramid, and the like, preferably including a horn shape.

Meanwhile, the light extracting structure 284 may be formed by a photoelectrochemical (PEC) method or the like, but is not limited thereto. Light generated from the active layer 230 may be transmitted through the light-transmitting electrode layer (not shown) or the first semiconductor layer 220 (not shown) as the light extracting structure 284 is formed on the upper surface of the light- It is possible to prevent light from being totally reflected from the upper surface of the light emitting device 220 and being reabsorbed or scattered, thereby contributing to improvement of light extraction efficiency of the light emitting device 200.

The passivation 290 may be formed on the side and upper regions of the light emitting structure 260 and the passivation 290 may be formed of an insulating material.

FIG. 5 is a perspective view illustrating a light emitting device package including the light emitting device according to the embodiment, and FIG. 6 is a cross-sectional view illustrating a light emitting device package including the light emitting device according to the embodiment.

5 and 6, the light emitting device package 500 includes a body 510 having a cavity 520, first and second lead frames 540 and 550 mounted on the body 510, A light emitting device 530 electrically connected to the first and second lead frames 540 and 550 and an encapsulant (not shown) encapsulated in the cavity 520 to cover the light emitting device 530.

The body 510 may be made of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), liquid crystal polymer (PSG), polyamide 9T (SPS), a metal material, sapphire (Al ₂ O ₃ ), beryllium oxide (BeO), and a printed circuit board (PCB). The body 510 may be formed by injection molding, etching, or the like, but is not limited thereto.

The inner surface of the body 510 may be formed with an inclined surface. The reflection angle of the light emitted from the light emitting device 530 can be changed according to the angle of the inclined surface, and thus the directivity angle of the light emitted to the outside can be controlled.

Concentration of light emitted to the outside from the light emitting device 530 increases as the directivity angle of light decreases. Conversely, as the directivity angle of light increases, the concentration of light emitted from the light emitting device 530 decreases.

The shape of the cavity 520 formed in the body 510 may be circular, rectangular, polygonal, elliptical, or the like, and may have a curved shape, but the present invention is not limited thereto.

The light emitting element 530 is mounted on the first lead frame 540 and may be a light emitting element that emits light such as red, green, blue, or white, or a UV (Ultra Violet) However, the present invention is not limited thereto. In addition, one or more light emitting elements 530 may be mounted.

The light emitting device 530 may be a horizontal type or a vertical type formed on the upper or lower surface of the light emitting device 530 or a flip chip Applicable.

The encapsulant (not shown) may be filled in the cavity 520 to cover the light emitting device 530.

The encapsulant (not shown) may be formed of silicon, epoxy, or other resin material. The encapsulant may be filled in the cavity 520 and ultraviolet or thermally cured.

In addition, the encapsulant (not shown) may include a phosphor, and the phosphor may be selected to be a wavelength of light emitted from the light emitting device 530 so that the light emitting device package 500 may emit white light.

The phosphor may be one of a blue light emitting phosphor, a blue light emitting phosphor, a green light emitting phosphor, a sulfur green light emitting phosphor, a yellow light emitting phosphor, a yellow red light emitting phosphor, an orange light emitting phosphor, and a red light emitting phosphor depending on the wavelength of light emitted from the light emitting device 530 Can be applied.

That is, the phosphor may be excited by the light having the first light emitted from the light emitting device 530 to generate the second light. For example, when the light emitting element 530 is a blue light emitting diode and the phosphor is a yellow phosphor, the yellow phosphor may be excited by blue light to emit yellow light, and blue light and blue light emitted from the blue light emitting diode As the excited yellow light is mixed, the light emitting device package 500 can provide white light.

Similarly, when the light emitting element 530 is a green light emitting diode, the magenta phosphor or the blue and red phosphors are mixed, and when the light emitting element 530 is a red light emitting diode, the cyan phosphors or the blue and green phosphors are mixed For example.

Such a fluorescent material may be a known fluorescent material such as a YAG, TAG, sulfide, silicate, aluminate, nitride, carbide, nitridosilicate, borate, fluoride or phosphate.

The first and second lead frames 540 and 550 may be formed of a metal material such as titanium, copper, nickel, gold, chromium, tantalum, (Pt), tin (Sn), silver (Ag), phosphorus (P), aluminum (Al), indium (In), palladium (Pd), cobalt (Co), silicon (Si), germanium , Hafnium (Hf), ruthenium (Ru), and iron (Fe). Also, the first and second lead frames 540 and 550 may be formed to have a single layer or a multilayer structure, but the present invention is not limited thereto.

The first and second lead frames 540 and 550 are separated from each other and electrically separated from each other. The light emitting element 530 is mounted on the first and second lead frames 540 and 550 and the first and second lead frames 540 and 550 are in direct contact with the light emitting element 530, And may be electrically connected through a conductive material such as a conductive material. In addition, the light emitting device 530 may be electrically connected to the first and second lead frames 540 and 550 through wire bonding, but is not limited thereto. Accordingly, when power is supplied to the first and second lead frames 540 and 550, power may be applied to the light emitting device 530. Meanwhile, a plurality of lead frames (not shown) may be mounted in the body 510 and each lead frame (not shown) may be electrically connected to the light emitting device 530, but is not limited thereto.

The light emitting device according to the embodiment can be applied to a lighting device. The lighting system includes a structure in which a plurality of light emitting elements are arrayed and includes a display device shown in Figs. 7 and 8, a lighting device shown in Fig. 9, and may include a lighting lamp, a traffic light, a vehicle headlight, have.

7 is an exploded perspective view of a display device having a light emitting device according to an embodiment.

7, a display device 1000 according to an embodiment includes a light guide plate 1041, a light source module 1031 for providing light to the light guide plate 1041, and a reflection member 1022 An optical sheet 1051 on the light guide plate 1041 and a display panel 1061 on the optical sheet 1051 and the light guide plate 1041 and the light source module 1031 and the reflection member 1022 But is not limited to, a bottom cover 1011.

The bottom cover 1011, the reflective sheet 1022, the light guide plate 1041, and the optical sheet 1051 can be defined as a light unit 1050.

The light guide plate 1041 serves to diffuse light into a surface light source. The light guide plate 1041 may be made of a transparent material, for example, acrylic resin such as polymethylmethacrylate (PET), polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin copolymer (COC), and polyethylene naphtha late Resin. &Lt; / RTI >

The light source module 1031 provides light to at least one side of the light guide plate 1041, and ultimately acts as a light source of the display device.

The light source module 1031 includes at least one light source module 1031 and may directly or indirectly provide light from one side of the light guide plate 1041. The light source module 1031 includes a substrate 1033 and a light emitting device 1035 according to the embodiment described above and the light emitting devices 1035 may be arrayed at a predetermined interval on the substrate 1033 .

The substrate 1033 may be a printed circuit board (PCB) including a circuit pattern (not shown). However, the substrate 1033 may include not only a general PCB, but also a metal core PCB (MCPCB), a flexible PCB (FPCB), and the like. When the light emitting element 1035 is mounted on the side surface of the bottom cover 1011 or on the heat radiation plate, the substrate 1033 can be removed. Here, a part of the heat radiating plate may be in contact with the upper surface of the bottom cover 1011.

The plurality of light emitting devices 1035 may be mounted on the substrate 1033 such that the light emitting surface is spaced apart from the light guiding plate 1041 by a predetermined distance. However, the present invention is not limited thereto. The light emitting device 1035 may directly or indirectly provide light to the light-incident portion, which is one surface of the light guide plate 1041, but the present invention is not limited thereto.

The reflective member 1022 may be disposed under the light guide plate 1041. The reflection member 1022 reflects the light incident on the lower surface of the light guide plate 1041 so as to face upward, thereby improving the brightness of the light unit 1050. The reflective member 1022 may be formed of, for example, PET, PC, or PVC resin, but is not limited thereto. The reflective member 1022 may be an upper surface of the bottom cover 1011, but is not limited thereto.

The bottom cover 1011 may house the light guide plate 1041, the light source module 1031, the reflective member 1022, and the like. To this end, the bottom cover 1011 may be provided with a housing portion 1012 having a box-like shape with an opened upper surface, but the present invention is not limited thereto. The bottom cover 1011 may be coupled to the top cover, but is not limited thereto.

The bottom cover 1011 may be formed of a metal material or a resin material, and may be manufactured using a process such as press molding or extrusion molding. In addition, the bottom cover 1011 may include a metal or a non-metal material having good thermal conductivity, but the present invention is not limited thereto.

The display panel 1061 is, for example, an LCD panel, including first and second transparent substrates facing each other, and a liquid crystal layer interposed between the first and second substrates. A polarizing plate may be attached to at least one surface of the display panel 1061, but the present invention is not limited thereto. The display panel 1061 displays information by light passing through the optical sheet 1051. Such a display device 1000 can be applied to various types of portable terminals, monitors of notebook computers, monitors of laptop computers, televisions, and the like.

The optical sheet 1051 is disposed between the display panel 1061 and the light guide plate 1041 and includes at least one light-transmitting sheet. The optical sheet 1051 may include at least one of a sheet such as a diffusion sheet, a horizontal and vertical prism sheet, and a brightness enhancement sheet. The diffusion sheet diffuses incident light, and the horizontal and / or vertical prism sheet condenses incident light into a display area. The brightness enhancing sheet improves the brightness by reusing the lost light. A protective sheet may be disposed on the display panel 1061, but the present invention is not limited thereto.

Here, the optical path of the light source module 1031 may include the light guide plate 1041 and the optical sheet 1051 as an optical member, but the invention is not limited thereto.

8 is a view showing a display device having a light emitting device according to an embodiment.

8, the display device 1100 includes a bottom cover 1152, a substrate 1120 on which the above-described light emitting device 1124 is arrayed, an optical member 1154, and a display panel 1155.

The substrate 1120 and the light emitting device 1124 may be defined as a light source module 1160. The bottom cover 1152, the at least one light source module 1160, and the optical member 1154 may be defined as a light unit 1150. The bottom cover 1152 may include a receiving portion 1153, but the present invention is not limited thereto. The light source module 1160 includes a substrate 1120 and a plurality of light emitting devices 1124 arranged on the substrate 1120.

Here, the optical member 1154 may include at least one of a lens, a light guide plate, a diffusion sheet, a horizontal and vertical prism sheet, and a brightness enhancement sheet. The light guide plate may be made of a PC material or a polymethyl methacrylate (PMMA) material, and the light guide plate may be removed. The diffusion sheet diffuses incident light, and the horizontal and vertical prism sheets condense incident light into a display area. The brightness enhancing sheet enhances brightness by reusing the lost light.

The optical member 1154 is disposed on the light source module 1160 and performs surface light source, diffusion, and light condensation of light emitted from the light source module 1160.

9 is an exploded perspective view of a lighting device having a light emitting device according to an embodiment.

9, the lighting apparatus according to the embodiment includes a cover 2100, a light source module 2200, a heat discharger 2400, a power supply unit 2600, an inner case 2700, and a socket 2800 . Further, the illumination device according to the embodiment may further include at least one of the member 2300 and the holder 2500. The light source module 2200 may include a light emitting device according to an embodiment of the present invention.

For example, the cover 2100 may have a shape of a bulb or a hemisphere, and may be provided in a shape in which the hollow is hollow and a part is opened. The cover 2100 may be optically coupled to the light source module 2200. For example, the cover 2100 may diffuse, scatter, or excite light provided from the light source module 2200. The cover 2100 may be a kind of optical member. The cover 2100 may be coupled to the heat discharging body 2400. The cover 2100 may have an engaging portion that engages with the heat discharging body 2400.

The inner surface of the cover 2100 may be coated with a milky white paint. Milky white paints may contain a diffusing agent to diffuse light. The surface roughness of the inner surface of the cover 2100 may be larger than the surface roughness of the outer surface of the cover 2100. This is for sufficiently diffusing and diffusing the light from the light source module 2200 and emitting it to the outside.

The cover 2100 may be made of glass, plastic, polypropylene (PP), polyethylene (PE), polycarbonate (PC), or the like. Here, polycarbonate is excellent in light resistance, heat resistance and strength. The cover 2100 may be transparent so that the light source module 2200 is visible from the outside, and may be opaque. The cover 2100 may be formed by blow molding.

The light source module 2200 may be disposed on one side of the heat discharging body 2400. Accordingly, heat from the light source module 2200 is conducted to the heat discharger 2400. The light source module 2200 may include a light emitting device 2210, a connection plate 2230, and a connector 2250.

The member 2300 is disposed on the upper surface of the heat discharging body 2400 and has guide grooves 2310 into which the plurality of light emitting elements 2210 and the connector 2250 are inserted. The guide groove 2310 corresponds to the substrate of the light emitting device 2210 and the connector 2250.

The surface of the member 2300 may be coated or coated with a light reflecting material. For example, the surface of the member 2300 may be coated or coated with a white paint. The member 2300 reflects the light reflected by the inner surface of the cover 2100 toward the cover 2100 in the direction toward the light source module 2200. Therefore, the light efficiency of the illumination device according to the embodiment can be improved.

The member 2300 may be made of an insulating material, for example. The connection plate 2230 of the light source module 2200 may include an electrically conductive material. Therefore, electrical contact can be made between the heat discharging body 2400 and the connecting plate 2230. The member 2300 may be formed of an insulating material to prevent an electrical short circuit between the connection plate 2230 and the heat discharging body 2400. The heat discharger 2400 receives heat from the light source module 2200 and heat from the power supply unit 2600 to dissipate heat.

The holder 2500 blocks the receiving groove 2719 of the insulating portion 2710 of the inner case 2700. Therefore, the power supply unit 2600 housed in the insulating portion 2710 of the inner case 2700 is sealed. The holder 2500 has a guide protrusion 2510. The guide protrusion 2510 may have a hole through which the protrusion 2610 of the power supply unit 2600 passes.

The power supply unit 2600 processes or converts an electrical signal provided from the outside and provides the electrical signal to the light source module 2200. The power supply unit 2600 is housed in the receiving groove 2719 of the inner case 2700 and is sealed inside the inner case 2700 by the holder 2500.

The power supply unit 2600 may include a protrusion 2610, a guide unit 2630, a base 2650, and a protrusion 2670.

The guide portion 2630 has a shape protruding outward from one side of the base 2650. The guide portion 2630 may be inserted into the holder 2500. A plurality of components may be disposed on one side of the base 2650. The plurality of components include, for example, a DC converter for converting AC power supplied from an external power source into DC power, a driving chip for controlling driving of the light source module 2200, an ESD (ElectroStatic discharge) protective device, and the like, but the present invention is not limited thereto.

The protrusion 2670 has a shape protruding outward from the other side of the base 2650. The protrusion 2670 is inserted into the connection portion 2750 of the inner case 2700 and receives an external electrical signal. For example, the protrusion 2670 may be equal to or smaller than the width of the connection portion 2750 of the inner case 2700. One end of each of the positive wire and the negative wire is electrically connected to the protrusion 2670 and the other end of the positive wire and the negative wire are electrically connected to the socket 2800.

The inner case 2700 may include a molding part together with the power supply part 2600. The molding part is a hardened portion of the molding liquid so that the power supply unit 2600 can be fixed inside the inner case 2700.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

A first semiconductor layer;
An electron blocking layer disposed on the first semiconductor layer;
A strain relief layer disposed on the electron blocking layer to relax a strain generated in the semiconductor layer;
An active layer on the strain relief layer; And
And a light emitting structure including a second semiconductor layer on the active layer,
Wherein the electron blocking layer comprises InGaN,
Wherein the strain relief layer is formed by alternately stacking at least two pairs of InGaN layers and GaN layers,
Wherein a content ratio of In of the electron blocking layer is larger than a content ratio of In of the InGaN layer of the strain relaxation layer.

The method according to claim 1,
Wherein an energy band gap of the electron blocking layer is larger than an energy band gap of the strain relief layer.

The method according to claim 1,
Wherein the thickness of the electron blocking layer is thicker than the thickness of the InGaN layer and the GaN layer.

The method according to claim 1,
Wherein a content ratio of In of the electron blocking layer is 10% to 25%.

The method according to claim 1,
And the content ratio of In in the InGaN layer is 1% to 10%.

The method according to claim 1,
Wherein the thickness of the electron blocking layer is 1 nm to 10 nm.

The method according to claim 1,
And the electron blocking layer is in contact with the InGaN layer of the strain relief layer.

The method according to claim 1,
And the electron blocking layer is in contact with the GaN layer of the strain relief layer.

The method according to claim 1,
Wherein the strain relief layer comprises at least two subgroups,
At least two pairs of the InGaN layer and the GaN layer are alternately stacked in the subgroup,
Wherein the thickness of the sub-group is thicker adjacent to the active layer.

10. The method of claim 9,
Wherein the number of the InGaN layers and the number of GaN layers in each subgroup are equal to each other.

The method according to claim 1,
The InGaN layer has a compressive stress,
Wherein the GaN layer has a tensile stress.

11. The method of claim 10,
Wherein the thickness of the InGaN layer is constant in the subgroup.

13. The method of claim 12,
Wherein a thickness of the InGaN layer in the subgroup adjacent to the active layer is thicker than a thickness of the InGaN layer in the subgroup adjacent to the first semiconductor layer.

13. The method of claim 12,
Wherein a thickness of the InGaN layer in the subgroup is thicker as the subgroup is adjacent to the active layer.

14. The method of claim 13,
Wherein a thickness of the GaN layer in each of the subgroups is equal to a thickness of the GaN layer in the other subgroups.

15. The method according to any one of claims 12 to 14,
Wherein the GaN layer thickness is constant in the subgroup.

17. The method of claim 16,
Wherein a thickness of the GaN layer in the subgroup adjacent to the active layer is thicker than a thickness of the GaN layer in the subgroup adjacent to the first semiconductor layer.

17. The method of claim 16,
Wherein the thickness of the GaN layer in the sub-group is thicker as the sub-group is adjacent to the active layer.

10. The method of claim 9,
Wherein the In concentration of the InGaN layer in the subgroup is higher as the subgroup is adjacent to the active layer.

10. The method of claim 9,
Wherein the InGaN layer and the GaN layer have a thickness of 1 nm to 1 nm.

10. The method of claim 9,
Wherein the thickness of the GaN layer is greater than or equal to the thickness of the InGaN layer.

10. The method of claim 9,
The strain relief layer has a supper lattice structure.

14. The method of claim 13,
And the thickness of the InGaN layer of the subgroup adjacent to the active layer is equal to the thickness of the barrier layer or the well layer constituting the active layer.

18. The method of claim 17,
And the thickness of the GaN layer of the subgroup adjacent to the active layer is equal to the thickness of the barrier layer or the well layer constituting the active layer.

A light emitting device package comprising the light emitting device according to any one of claims 1 to 24.

An illumination system comprising the light-emitting device according to any one of claims 1 to 24.

A display device comprising the light-emitting element according to any one of claims 1 to 24.