KR20120042340A - Light emitting device - Google Patents

Abstract

PURPOSE: A light emitting device is provided to improve extraction efficiency of light emitting to a second conductivity type semiconductor layer from an active layer by forming a conductive layer on the second conductivity type semiconductor layer. CONSTITUTION: A light emitting structure(120) is arranged on a substrate(110). The light emitting structure comprises a conductive semiconductor layer(122), an active layer(124), and a second conductivity type semiconductor layer(126). A conductive layer(130) is arranged on the second conductivity type semiconductor layer. A first electrode(142) is arranged on a first conductivity type semiconductor layer which is exposed by an etching process. A second electrode(144) is arranged on the conductive layer.

Description

Light emitting device

An embodiment relates to a light emitting device.

Light emitting devices such as light emitting diodes or laser diodes using semiconductors of Group 3-5 or 2-6 compound semiconductor materials of semiconductors have various colors such as red, green, blue and ultraviolet rays due to the development of thin film growth technology and device materials. It is possible to realize efficient white light by using fluorescent materials or combining colors, and it has low power consumption, semi-permanent life, fast response speed, safety and environmental friendliness compared to conventional light sources such as fluorescent and incandescent lamps. Has an advantage.

Therefore, a white light emitting device that can replace a fluorescent light bulb or an incandescent bulb that replaces a Cold Cathode Fluorescence Lamp (CCFL) constituting a backlight of a transmission module of an optical communication means and a liquid crystal display (LCD) display device. Applications are expanding to diode lighting devices, automotive headlights and traffic lights.

Embodiments provide a light emitting device capable of improving internal quantum efficiency and light output.

The embodiment includes a substrate and a light emitting structure in which a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer are stacked on the substrate, wherein the active layer is alternately stacked two or more times with a well layer and a barrier layer. The energy band gap of the barrier layer between at least two or more well layers sequentially adjacent to the second conductivity type semiconductor layer is smaller than the energy band gap of the remaining barrier layers.

At least two or more well layers sequentially adjacent to the second conductivity type semiconductor layer have a continuous energy level and a quantized energy level around a reference energy band. In addition, the reference energy band may be an energy band of the barrier layer between at least two or more well layers sequentially adjacent to the second conductivity type semiconductor layer. The energy band higher than the reference energy band may have a continuous energy level, and the energy band lower than the reference energy band may have a quantized energy level.

In addition, at least two or more well layers sequentially adjacent to the second conductive semiconductor layer may share at least one first energy level and have at least one second energy level that is quantized independently of each other.

Another embodiment includes a substrate, an active layer on the first conductive semiconductor layer having a first conductive semiconductor layer, well layers and barrier layers on the substrate, a second conductive semiconductor layer on the active layer, the well layer And the barrier layers are nitride semiconductor layers containing indium, and the indium content of the first barrier layer located between at least two or more well layers sequentially adjacent from the second conductivity type semiconductor layer among the well layers. Is greater than the indium content of the second barrier layer located between the remaining well layers and less than the indium content of the well layers.

Embodiments can improve internal quantum efficiency and light output.

1 shows a light emitting device according to an embodiment.
2 illustrates an energy band gap of a multi quantum well structure of an active layer according to an embodiment.
FIG. 3 shows the radiation recombination of the multiple quantum well structure shown in FIG. 2 upon current injection.
4 shows an energy band diagram of a typical multi quantum well structure during current injection.
5 shows an energy band diagram of a multi quantum well structure at current injection in accordance with an embodiment.
6 shows light output characteristics of the multi-quantum well structure according to the embodiment.
7 shows the internal quantum efficiency of a multi quantum well structure according to an embodiment.
8 shows an energy band gap of a multi-quantum well structure of a typical active layer.
9 shows radiation recombination of multiple quantum well structures of a typical active layer during current injection.
10 illustrates a light emitting device according to another embodiment.
11 illustrates a light emitting device package according to an embodiment.

Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings.

In the description of the embodiments, it is to be understood that each layer (film), region, pattern or structure is formed "on" or "under" a substrate, each layer The terms " on "and " under " encompass both being formed" directly "or" indirectly " In addition, the criteria for the top or bottom of each layer will be described with reference to the drawings.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

1 shows a light emitting device 100 according to an embodiment. Referring to FIG. 1, the light emitting device 100 includes a substrate 110, a light emitting structure 120, a conductive layer 130, a first electrode 142, and a second electrode 144.

The substrate 110 may be any one of a sapphire substrate, a silicon (Si) substrate, a zinc oxide (ZnO) substrate, and a nitride semiconductor substrate, or a template substrate on which at least one of GaN, InGaN, AlGaN, and AlInGaN is stacked. have.

The light emitting structure 120 is disposed on the substrate 110 and has a structure in which the first conductive semiconductor layer 122, the active layer 124, and the second conductive semiconductor layer 126 are stacked. In addition, a portion of the second conductive semiconductor layer 126, the active layer 124, and the first conductive semiconductor layer 122 is etched in the light emitting structure 120 to expose a portion of the first conductive semiconductor layer 122. .

In order to alleviate the difference between the lattice constant and the coefficient of thermal expansion, a buffer layer (not shown) may be interposed between the substrate 110 and the light emitting structure 120, and the crystallinity of the first conductivity-type semiconductor layer 122 may be improved. An undoped semiconductor layer (not shown) may be interposed therebetween.

In this case, the buffer layer may be grown at a low temperature, and the material may be a GaN layer or an AlN layer, but is not limited thereto. The undoped semiconductor layer may be lower than the first conductive semiconductor layer 122 because the n-type dopant is not doped. It may be the same as the first conductivity type semiconductor layer 122 except for having electrical conductivity.

The conductive layer 130 is disposed on the second conductive semiconductor layer 126 to increase the extraction efficiency of light emitted from the active layer 124 to the second conductive semiconductor layer 126. The conductive layer may be made of a transparent oxide material having high transmittance, such as indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), zinc oxide (ZnO), or the like. have.

The first electrode 142 is disposed on the first conductive semiconductor layer 122 exposed by etching, and the second electrode 144 is disposed on the conductive layer 130.

The first conductive semiconductor layer 122 is disposed on the substrate 110 and may be an n-type semiconductor layer. For example, semiconductor material having a compositional formula of the first conductive type semiconductor layer 122 is _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, and the like may be selected, and n-type dopants such as Si, Ge, Sn, Se, Te, and the like may be doped.

The active layer 124 is disposed on the first conductivity type semiconductor layer 122.

The second conductive semiconductor layer 126 is disposed on the active layer 124 and may be a p-type semiconductor layer. For example, the second conductivity type semiconductor material having a composition formula of the semiconductor layer 126 is _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, etc. may be selected, and p-type dopants such as Mg, Zn, Ca, Sr, and Ba may be doped.

The active layer 124 generates light by energy generated in the process of recombination of electrons provided from the n-type semiconductor layer 122 and holes provided from the p-type semiconductor layer 126. Can be.

The active layer 124 may include a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x + y≤1), and the active layer 124 may be a multi quantum well structure (MQW) in which a quantum well layer and a quantum barrier layer are alternately stacked two or more times.

In this case, the multi-quantum well structure includes quantum well layers and quantum barrier layers spaced apart from the first conductive semiconductor layer 122 in the direction of the second conductive semiconductor layer 126. Each of the quantum barrier layers is disposed between adjacent quantum well layers.

At least two or more quantum barrier layers between at least two or more quantum well layers (hereinafter referred to as "first quantum well layers") sequentially adjacent from the second conductivity type semiconductor 126 in a multi quantum well structure ( The energy band gap of the following "first quantum barrier layers" is smaller than the energy band gap of the remaining quantum barrier layers (hereinafter referred to as "second quantum barrier layers") except for the first quantum barrier layers.

That is, the energy band gap of the first quantum barrier layers is greater than the energy band gap of the second quantum barrier layers adjacent to the quantum well layers (hereinafter referred to as "second quantum well layers") except for the first quantum well layers. small.

In addition, the first quantum well layers have a continuous energy level and a quantized energy level based on the reference energy band. The reference energy band may be an energy band of the first quantum barrier layers.

The first quantum well layers share a continuous energy level seen in bulk at an energy band higher than the reference energy band, and are each quantized individually in an energy band lower than the reference energy band.

2 illustrates an energy band gap of the multiple quantum well structure (MQW) of the active layer 124 according to an embodiment. Referring to FIG. 2, the multi-quantum well structure MQW includes seven quantum well layers QW1 to QW7 and six quantum barriers spaced apart from each other between the first semiconductor layer 122 and the second semiconductor layer 126. Layers QB1 to QB6. At this time, any one of the quantum barrier layers is disposed between adjacent well layers QW1 and QW2, QW2 and QW3, QW3 and QW4, QW4 and QW5, QW5 and QW6, and QW6 and QW7. The energy band gaps E3 of the quantum well layers QW1 to QW7 are the same.

Four quantum well layers QW4 to QW7 sequentially adjacent from the second conductive semiconductor layer 126 become “first quantum well layers”, and the remaining quantum well layers except for the first quantum well layers ( QW1 to QW3) become second quantum well layers.

The barrier layer disposed between adjacent first quantum well layers QW4 to QW7 becomes “first quantum barrier layers QB4 to QB6”. In addition, the remaining quantum barrier layers QB1 to QB3 except for the first quantum barrier layers QB4 to QB6 become “second quantum barrier layers”.

The energy band gap E3 of the second quantum well layers QW1 to QW3 and the first quantum well layers QW4 to QW7 are all the same. The energy band gap E2 of the first quantum barrier layers QB4, QB5, and QB6 may include the energy band gaps of the first quantum well layers QW1 to QW3 and the second quantum well layers QW4 to QW7. Greater than E3) and less than the energy band gap E1 of the second quantum barrier layers QB1, QB2, QB3 (E3 <E2 <E1).

The first quantum well layers by lowering the energy band gap of the first quantum barrier layers QB4 to QB6 existing between the first quantum well layers QW4 to QW7 than the energy band gap of the second quantum barrier layers. QW4 to QW7 share at least one first energy level (eg, n = 2) and have at least one second energy level (eg, n = 1) that is quantized independently of each other. Wherein at least one first energy level is a continuous quantum level and at least one second energy level is a quantized energy level. The at least one first energy level may also be a plurality of consecutive quantum levels having different levels, and the at least one second energy level may be quantized energy levels having a plurality of different levels.

8 shows an energy band gap of a multi-quantum well structure of a typical active layer. Referring to FIG. 8, in general, quantization energy levels in a quantum well layer may only retain a certain amount of electrons or holes in quantum mechanics. Therefore, when the quantity of electrons injected from the electron injection layer or the hole injected from the hole injection layer is large enough, surplus electrons or excess holes that are not effectively bound in the quantum well layers W1 to W7 may occur. These surplus electrons or surplus holes do not participate in generating light and are self-extinguishing in the active layer or leak out of the active layer. As a result, when the injected current is increased, the non-luminescence loss of electrons and holes is increased, thereby reducing the emission efficiency (Internal Quantum Efficiency) of the active layer.

In particular, since the hole mobility is generally low at the time of high current injection, the hole injection is not smooth and uniform throughout the multi-quantum well structure. Therefore, light emission mainly occurs at the last quantum well W7 of the multi-quantum well structure. As a result, uniform light emission does not occur in all regions of the active layer, thereby reducing light emission efficiency.

However, FIG. 2 shows that the multi-quantum well structure of the active layer 124 according to the embodiment efficiently transfers electrons or holes to the first quantum through at least one first energy level (for example, n = 2) which is shared with each other during current injection. It can be uniformly transported and distributed into the well layers QW4 to QW7, and can emit light independently at at least one second energy level of each of the first quantum well layers QW4 to QW7. have. Therefore, the four quantum well layers QW4 to QW7 may emit light uniformly, thereby improving internal quantum efficiency IQE and output power characteristics of the light emitting device 100 during current injection.

FIG. 9 shows radiation recombination of a multi quantum well structure of a typical active layer during current injection, and FIG. 3 shows radiation recombination of the multi quantum well structure (MQW) shown in FIG. 2 during current injection. 3 and 9, when a current (eg, I = 600 A / m, A / m is Ampere per meter) is injected, light emission mainly occurs in the last quantum well layer W7 in a general multi quantum well structure. In the multi-quantum well structure according to the embodiment, it can be seen that light emission by radiative recombination occurs in each of the first four quantum well layers QW4 to QW7. Accordingly, the internal quantum efficiency (IQE) may be improved in the embodiment, compared to a general multi quantum well structure in which light emission is mainly generated at the last quantum well W7 of the multi quantum well structure during current injection.

4 is an energy band diagram of a general multi quantum well structure during current injection, and FIG. 5 is an energy band diagram of a multi quantum well structure during current injection according to an embodiment.

Referring to FIG. 4, in a general multi-quantum well structure, a wave function 501 is located at the quantized energy levels of the quantum well layers W1 to W7. On the other hand, referring to FIG. 5, in the multi-quantum well structure according to the embodiment, wave functions exist in the quantized energy levels of the first quantum well layers QW4 to QW7 as well as continuous quantum energy levels shared with each other. Since the wave functions exist, it can be seen that holes are uniformly distributed in the first quantum well layers QW4 to QW7. In addition, in the case of the embodiment, since the Fermi level (Quasi-Fermi level, 603) of the hole in the active layer is lower than the Fermi level 503 of the general multi-quantum well structure, it can be seen that there is a high probability that more holes can be distributed in the active layer. have.

FIG. 6 shows the output power characteristics of the multi quantum well structure according to the embodiment, and FIG. 7 shows the internal quantum efficiency of the multi quantum well structure according to the embodiment. Here, g1 and f1 each represent an output power and an internal quantum efficiency (IQE) of a light emitting device having a multi quantum well structure according to an embodiment, and g2 and f2 are light of a light emitting device having a general multi quantum well structure. Output and internal quantum efficiency are shown.

6 and 7, g1> g2 and f1> f2 upon injection of current (eg, I = 600 A / m). Therefore, in the current injection, the light emitting device according to the embodiment improves the light output and the internal quantum efficiency.

The first and second quantum well layers QW1 to QW7 may have a composition of In _x Ga _{1 - x} N (0 ≦ _x ≦ 1), and the first quantum barrier layers QB4 to QB6 may be In _y Ga. _It may have a composition of _{1 - y} N (0 ≦ _y ≦ 1), and the second quantum barrier layers QB1 to QB3 may have a composition of In _z Ga _{1 - z} N (0 ≦ _z ≦ 1).

The content ratio y of the indium In of the first quantum barrier layers QB4 to QB6 is greater than the content ratio z of the indium In of the second quantum barrier layers QB1 to QB3. And less than the content ratio x of indium of the second quantum well layers (z <y <x).

For example, the indium content ratio (x) of the first and second quantum well layers QW1 to QW7 may be 0.14 to 0.15, and preferably 0.147. In addition, the indium content ratio y of the first quantum barrier layers QB4 to QB6 may be 0.05 to 0.1, and preferably 0.08. The indium content ratio z of the second quantum barrier layers QB1 to QB3 may be 0.01 to 0.05, preferably 0.02.

For carrier confinement, the thickness or width of the first quantum barrier layers QB4 to QB6 may be 5 nm to 15 nm. Also, in order to have at least one quantized energy level, the thickness or width of the first quantum well layers QW4 to QW7 may be 10 nm to 15 nm.

10 illustrates a light emitting device 200 according to another embodiment. Referring to FIG. 10, the light emitting device 200 includes a second electrode layer 205, a protective layer 230, a light emitting structure 240, a passivation layer 250, and a first electrode 255.

The second electrode layer 205 includes a support substrate 210, a bonding layer 215, a reflective layer 220, and an ohmic layer 225. The support substrate 210 supports the light emitting structure 240, and supplies power to the light emitting structure 240 together with the first electrode 255. The support substrate 210 is conductive, for example copper (Cu), gold (Au), nickel (Ni), molybdenum (Mo), copper-tungsten (Cu-W), carrier wafers (eg, Si , Ge, GaAs, ZnO, SiC).

The bonding layer 215 is formed on the support substrate 210. The bonding layer 215 is a bonding layer and is formed below the reflective layer 220. The bonding layer 215 may be in contact with the reflective layer 220 and the ohmic layer 225 so that the reflective layer 220 and the ohmic layer 225 may be bonded to the supporting substrate 210. The bonding layer 215 may include a barrier metal or a bonding metal, and may include, for example, at least one of Ti, Au, Sn, Ni, Cr, Ga, In, Bi, Cu, Ag, or Ta.

The reflective layer 220 is formed on the bonding layer 215. The reflective layer 220 may reflect light incident from the light emitting structure 240, thereby improving light extraction efficiency. The reflective layer 220 may be formed of, for example, a metal or an alloy including at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf. In addition, the reflective layer 220 may be formed in a multilayer using a metal or an alloy and a light-transmitting conductive material such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, or ATO. For example, IZO / Ni, AZO / Ag, It can be laminated with IZO / Ag / Ni, AZO / Ag / Ni and the like. The reflective layer 220 is to increase the light efficiency and does not have to be formed.

The ohmic layer 225 is formed on the reflective layer 220. The ohmic layer 225 is in ohmic contact with the second conductive semiconductor layer 242 of the light emitting structure 240 so that power can be smoothly supplied to the light emitting structure 240. The ohmic layer 225 may selectively use a transparent conductive layer and a metal, and may include indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IZAO), and IGZO (IG). indium gallium zinc oxide (IGTO), indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrO _x , RuO _x , RuO _x / ITO, Ni, Ag, One or more of Ni / IrO _x / Au and Ni / IrO _x / Au / ITO can be used to implement a single layer or multiple layers.

The ohmic layer 225 is for smoothly injecting a carrier into the second conductivity-type semiconductor layer 242 and is not necessarily formed. For example, instead of separately forming the ohmic layer 225, the material used as the reflective layer 220 may be selected as a material in ohmic contact with the second conductivity-type semiconductor layer 242 to make ohmic contact.

The protective layer 230 is formed on the second electrode layer 205. The protective layer 135 may reduce a phenomenon in which the interface between the light emitting structure 240 and the bonding layer 215 is peeled off, thereby reducing the reliability of the light emitting device 200. The protective layer 135 may be a conductive protective layer formed of a conductive material or a non-conductive protective layer formed of a non-conductive material.

The light emitting structure 240 is formed on the second electrode layer 205. The light emitting structure 240 may have a structure in which the second conductive semiconductor layer 242, the active layer 244, and the first conductive semiconductor layer 246 are sequentially stacked on the second electrode layer 205.

The active layer 244 includes the first and second quantum well layers QW1 to QW7, the first quantum barrier layers QB4 to QB6, and the second quantum barrier layers QB1 to QB3 described with reference to FIG. 2. do. Therefore, as described above, since light emission is uniformly generated in each of the first quantum well layers QW4 to QW7 during current injection, the internal quantum efficiency of the multi-quantum well structure can be improved and the light output can be improved.

The passivation layer 250 may be formed on the side surface of the light emitting structure 240 to electrically protect the light emitting structure 240, but is not limited thereto. For example, the passivation layer 250 may be SiO ₂ , SiO _x , SiO _x N _y , Si ₃ N ₄ , to be formed of Al ₂ O ₃ Can be.

A roughness pattern 260 may be formed on the top surface of the first conductive semiconductor layer 246 to increase light extraction efficiency. The first electrode 255 is formed to contact the upper surface of the light emitting structure 240. The roughness pattern 260 may or may not be formed on a portion of the first conductivity-type semiconductor layer 246 under the first electrode 255.

11 illustrates a light emitting device package according to an embodiment. Referring to FIG. 11, the light emitting device package may include a package body 710, a first metal layer 712, a second metal layer 714, a light emitting device 720, a reflector 725, a wire 730, and an encapsulation layer ( 740).

The package body 710 has a structure in which a cavity is formed in one region. At this time, the side wall of the cavity may be formed to be inclined. The package body 710 may be formed of a substrate having good insulation or thermal conductivity, such as a silicon-based wafer level package, a silicon substrate, silicon carbide (SiC), aluminum nitride (AlN), or the like. It may have a structure in which a plurality of substrates are stacked. Embodiment is not limited to the material, structure, and shape of the body described above.

The first metal layer 712 and the second metal layer 714 are disposed on the surface 710 of the package body 710 to be electrically separated from each other in consideration of heat dissipation or mounting of a light emitting device. The light emitting device 720 is electrically connected to the first metal layer 712 and the second metal layer 714. In this case, the light emitting device 720 may be the light emitting device 100 or 200 illustrated in FIG. 1 or 10.

For example, the second electrode layer 205 of the light emitting device 200 is electrically connected to the second metal layer 714, the first electrode 255 is bonded to one side of the wire 730, and the other of the wire 730. The side may be bonded to the first metal layer 712.

For example, although not shown in FIG. 7, the first electrode 142 of the light emitting device 100 is electrically connected to the first metal layer 712, and the second electrode 144 is electrically connected to the second metal layer 714. Can be connected.

The reflector plate 725 is formed on the sidewall of the cavity of the package body 710 to direct light emitted from the light emitting device 100 or 200 in a predetermined direction. The reflector plate 725 is made of a light reflective material, and may be, for example, a metal coating or a metal flake.

The encapsulation layer 740 surrounds the light emitting device 720 positioned in the cavity of the package body 710 to protect the light emitting device 720 from the external environment. The encapsulation layer 740 is made of a colorless transparent polymer resin material such as epoxy or silicon. The encapsulation layer 740 may include a phosphor to change the wavelength of light emitted from the light emitting device 720. The light emitting device package may include at least one of the light emitting devices of the embodiments disclosed above, but is not limited thereto.

A plurality of light emitting device packages according to the embodiment may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, or the like, which is an optical member, may be disposed on an optical path of the light emitting device package. The light emitting device package, the substrate, and the optical member may function as a backlight unit.

Another embodiment may be implemented as a display device, an indicator device, or a lighting system including the light emitting device or the light emitting device package described in the above embodiments, and for example, the lighting system may include a lamp or a street lamp.

In addition, the above description has been made with reference to the embodiment, which is merely an example, and is not intended to limit the present invention. Those skilled in the art to which the present invention pertains will be illustrated as above without departing from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

110 substrate 120 light emitting structure
124: active layer 130: conductive layer
142: first electrode 144: second electrode
160: n-type electrode 170: p-type electrode
MQW: multi quantum well structure QW4 to QW7: first quantum well layers
QW1 to QW3: second quantum well layers QB4 to QB6: first quantum barrier layers QB3 to QB: second quantum barrier layers.

Claims (12)

Substrate: and
A light emitting structure in which a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer on the substrate are stacked;
The active layer,
A well layer and a barrier layer are alternately stacked two or more times, and the energy band gap of the barrier layer between at least two or more well layers sequentially adjacent from the second conductive semiconductor layer is larger than the energy band gap of the remaining barrier layers. Small light emitting element. The method of claim 1,
And at least two or more well layers sequentially adjacent to the second conductivity type semiconductor layer have a continuous energy level and a quantized energy level around a reference energy band. The method of claim 2,
The reference energy band is an energy band of the barrier layer between at least two or more well layers sequentially adjacent from the second conductivity type semiconductor layer. The method of claim 2,
And a continuous energy level in an energy band higher than the reference energy band, and a quantized energy level in an energy band lower than the reference energy band. The method of claim 1,
And at least two or more well layers sequentially adjacent to the second conductive semiconductor layer share at least one first energy level and have at least one second energy level that is quantized independently of each other. The method of claim 1,
The thickness of the barrier layer between at least two or more well layers sequentially adjacent to the second conductivity type semiconductor layer is 5 nm to 15 nm. The method of claim 1,
The light emitting device of claim 2, wherein the barrier layer between the at least two well layers adjacent to the second conductive semiconductor layer and the remaining barrier layers have different indium (In) contents. Board;
A first conductivity type semiconductor layer on the substrate;
An active layer on the first conductivity type semiconductor layer having well layers and barrier layers;
A second conductivity type semiconductor layer on the active layer,
The well layers and the barrier layers are nitride semiconductor layers comprising indium,
An indium content of at least one first barrier layer located between at least two or more well layers sequentially adjacent from the second conductivity type semiconductor layer among the well layers is at least one located between the remaining well layers. A light emitting device that is larger than the indium content of the second barrier layer and smaller than the indium content of the well layers. The method of claim 8,
The composition of the well layers is In _x Ga _{1 - x} N (0 ≦ _x ≦ 1), and the composition of the at least one first barrier layer is In _y Ga _{1 - y} N (0 ≦ _y ≦ 1). The composition of the at least one second barrier layer is In _z Ga _1-z N (0 ≦ _z ≦ 1), wherein z <y <x. The method of claim 8,
x is 0.14 to 0.15, y is 0.05 to 0.1, and z is 0.01 to 0.05. The method according to claim 1 or 8,
In the light emitting structure, a portion of the second conductive semiconductor layer, the active layer, and the first conductive semiconductor layer are etched to expose a portion of the first conductive semiconductor layer.
A conductive layer on the second conductive semiconductor layer;
A first electrode on the first conductive semiconductor layer exposed by the etching; And
The light emitting device further comprises a second electrode on the conductive layer. The method according to claim 1 or 8,
A bonding layer between the substrate and the light emitting structure;
A reflective layer and an ohmic layer between the bonding layer and the light emitting structure; And
The light emitting device further comprises an electrode on the light emitting structure.

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