KR20130031932A

KR20130031932A - Light emitting device

Info

Publication number: KR20130031932A
Application number: KR1020110095348A
Authority: KR
Inventors: 이선균; 나종호; 심상균
Original assignee: 엘지이노텍 주식회사
Priority date: 2011-09-21
Filing date: 2011-09-21
Publication date: 2013-03-29

Abstract

PURPOSE: A bonding wire including a rod coated with carbon allotrope is provided to improve oxidation resistance by preventing oxygen or carbon dioxide from penetrating into the rod. CONSTITUTION: A bonding wire includes a rod and a coating layer. The rod is made of copper, copper alloy, and hetero-metal coated copper/copper alloy. A coating layer includes diamond, and DLC(Diamond Like Carbon) and carbon nanotube. The coating layer is a single layer or multiple layers.

Description

Light Emitting Device {LIGHT EMITTING DEVICE}

An embodiment relates to a light emitting device.

LED (Light Emitting Diode) is a device that converts electrical signals into infrared, visible light or light using the characteristics of compound semiconductors. It is used in household appliances, remote controls, display boards, The use area of LED is becoming wider.

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.

LED semiconductors are grown by a process such as MOCVD or molecular beam epitaxy (MBE) on a substrate such as sapphire or silicon carbide (SiC) having a hexagonal system structure.

In the active layer, the holes provided in the p-type semiconductor layer and the electrons provided in the n-type semiconductor layer recombine to generate light. In the LED, improving the probability of recombination of holes and electrons in the active layer is an important issue for improving the light efficiency. In particular, it is important to maximize the light efficiency at 10 to 60A / cm ² within the driving range of commercialized products. In addition, there is a need to improve the efficiency efficiency (efficiency droop) by increasing the drive current density of the product. Therefore, consideration is required for a method of maintaining the mobility of holes in which mobility is lower than that of the former.

In the active layer, the holes provided in the p-type semiconductor layer and the electrons provided in the n-type semiconductor layer recombine to generate light. In the LED, improving the probability of recombination of holes and electrons in the active layer is an important issue for improving the light efficiency. Publication No. 10-2011-0072424 describes a technique for an active layer to increase the probability of recombination of electrons and holes.

The embodiment provides a light emitting device having improved light efficiency.

The light emitting device according to the embodiment includes a first conductive semiconductor layer doped with a first conductive type; An active layer of a multi-quantum well structure (MQW) disposed on the first conductivity type semiconductor layer and including a plurality of well layers and a barrier layer; A second conductive semiconductor layer doped with a second conductivity type disposed on the active layer, wherein each of the plurality of barrier layers is doped with a second conductivity type, and the doping concentration of the barrier layer is in the direction of the second conductive semiconductor layer. It can increase as you go.

In the light emitting device according to the embodiment, holes provided in the first conductivity-type semiconductor layer including indium in the barrier layer are evenly transferred to the plurality of well layers, thereby increasing luminous efficiency.

In the light emitting device according to the embodiment, the barrier layer is doped with a P-type dopant, thereby increasing the probability of recombination of holes and electrons, thereby improving internal quantum efficiency.

The light emitting device according to the embodiment may increase the hole mobility to improve the light efficiency degradation due to the increase of the driving current density.

The light emitting device according to the embodiment may increase the overlapping interval of the wave function of electrons and holes by adjusting the energy band gap of the barrier layer, thereby increasing the probability of recombination of electrons and holes.

1 is a cross-sectional view showing the structure of a light emitting device according to the embodiment;
2 is a partially enlarged cross-sectional view of a light emitting device according to the embodiment;
3A, 3B, and 3C are diagrams illustrating an energy band gap of a light emitting device according to an embodiment.
4 is a cross-sectional view showing the structure of a light emitting device according to the embodiment;
5 is a partially enlarged cross-sectional view of a light emitting device according to the embodiment;
6 is a graph illustrating internal quantum efficiency (IQE) according to current of a light emitting device;
7A is a perspective view showing a light emitting device package including the light emitting device of the embodiment,
FIG. 7B is a cross-sectional view illustrating a light emitting device package including the light emitting device of the embodiment,
8A is a perspective view illustrating a lighting device including a light emitting device module according to an embodiment,
FIG. 8B is a cross-sectional view illustrating a lighting device including a light emitting device module according to an embodiment,
9 is an exploded perspective view showing a backlight unit including a light emitting device module according to an embodiment, and
10 is an exploded perspective view showing a backlight unit including a light emitting device module according to an embodiment.

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 above or below each layer will be described with reference to the drawings.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. In addition, the size of each component does not necessarily reflect the actual size.

Hereinafter, embodiments will be described in detail with reference to the drawings.

1 is a cross-sectional view illustrating a structure of a light emitting device 100 according to an embodiment, and FIG. 2 is an enlarged cross-sectional view of a portion A of the light emitting device 100 of FIG. 1.

1 and 2, the light emitting device 100 according to the embodiment is disposed on the first conductive semiconductor layer 120 and the first conductive semiconductor layer 120 doped with a first conductivity type. An active layer 130 and an active layer 130 of the multi-quantum well structure (MQW) including a plurality of well layers Q1, Q2, Q3, and Q4 and barrier layers B1, B2, B3, and B4. A second conductive semiconductor layer 150 doped with a second conductivity type, each of the plurality of barrier layers B1, B2, B3, and B4 is doped with a second conductivity type, and the barrier layers B1, B2, and B3 , B4) may increase toward the second conductivity type semiconductor layer 150.

The substrate 110 may be disposed under the first conductivity type semiconductor layer 120. The substrate 110 may support the first conductivity type semiconductor layer 120. The substrate 110 may receive heat from the first conductivity type semiconductor layer 120. The substrate 110 may have a light transmissive property. The substrate 110 may have a light transmissive property when using a light transmissive material or formed below a predetermined thickness, but is not limited thereto. The refractive index of the substrate 110 may be smaller than the refractive index of the first conductivity type semiconductor layer 120 for light extraction efficiency.

The substrate 110 may be formed of a semiconductor material according to an embodiment, for example, silicon (Si), germanium (Ge), gallium arsenide (GaAs), zinc oxide (ZnO), silicon carbide (SiC), It may be implemented as a carrier wafer such as silicon germanium (SiGe), gallium nitride (GaN), gallium (III) oxide (Ga ₂ O ₃ ).

The substrate 110 may be formed of a conductive material according to an embodiment. According to the embodiment, the metal may be formed of, for example, gold (Au), nickel (Ni), tungsten (W), molybdenum (Mo), copper (Cu), aluminum (Al), tantalum (Ta), or silver. It may be formed of any one selected from (Ag), platinum (Pt), chromium (Cr) or formed of two or more alloys, and may be formed by stacking two or more of the above materials. When the substrate 110 is formed of a metal, the thermal stability of the light emitting device may be improved by facilitating the emission of heat generated from the light emitting device.

The substrate 110 may include a patterned substrate (PSS) structure on an upper surface thereof to increase light extraction efficiency, but is not limited thereto. The substrate 110 may improve the thermal stability of the light emitting device 100 by facilitating the emission of heat generated from the light emitting device 100. The substrate 110 may include a layer having a difference between the first conductivity type semiconductor layer 120 and the lattice constant, thereby alleviating the difference in the lattice constant between the first conductivity type semiconductor layer 120 and the first conductivity type semiconductor layer 120.

The buffer layer (not shown) may be disposed between the substrate 110 and the first conductivity type semiconductor layer 120. Buffer layers (not shown) include gallium nitride (GaN), indium nitride (InN), aluminum nitride (AlN), aluminum indium nitride (AlInN), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), and indium It may be formed of one or more materials of aluminum gallium nitride (InAlGaN), but is not limited thereto. The buffer layer (not shown) may be grown as a single crystal on the substrate 110.

The buffer layer (not shown) may mitigate lattice mismatch between the substrate 110 and the first conductivity-type semiconductor layer 120. The buffer layer (not shown) may allow the first conductivity type semiconductor layer 120 to be easily grown on the top surface. The buffer layer (not shown) may improve crystallinity of the first conductivity-type semiconductor layer 120 disposed on the upper surface. The buffer layer (not shown) may be made of a material that can alleviate the lattice constant difference between the substrate 110 and the first conductivity-type semiconductor layer 120.

The first conductivity type semiconductor layer 120 may be disposed on the substrate 110. The first conductivity type semiconductor layer 120 may be disposed on a buffer layer (not shown) to match the difference in lattice constant with the substrate 110, but is not limited thereto. The first conductive semiconductor layer 120 may be grown on the substrate 110, but is not limited to the horizontal light emitting device but may be applied to the vertical light emitting device.

A first conductive type semiconductor layer 120 may be implemented as an n-type semiconductor layer, the n-type semiconductor layer is for example, In _x Al _y Ga ₁ _-x- _y N (0≤x≤1, 0≤y≤ 1, 0 ≦ x + y ≦ 1, a semiconductor material, for example, gallium nitride (GaN), aluminum nitride (AlN), aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), or indium nitride (InN) ), InAlGaN, AlInN and the like. That is, the first conductivity type may be n-type. The first conductivity-type semiconductor layer 120 may be, for example, silicon (Si), germanium (Ge), tin (Sn), selenium (Se), and tellurium (Te). N-type dopant such as) may be doped.

The first conductivity type semiconductor layer 120 may receive power from the outside. The first conductivity type semiconductor layer 120 may provide electrons to the active layer 130.

The active layer 130 may be formed on the first conductivity type semiconductor layer 120. 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.

Well active layer 130 having a composition formula of In this case, formed of a quantum well structure, for _{example, In x Al y Ga 1 -x-} y N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) A barrier layer having a compositional formula of layers Q1, Q2, Q3, Q4 and In _a Al _b Ga ₁ _-a- _b N ( _{0≤a≤1, 0≤b≤1, 0≤a} + b≤1) It may have a quantum well structure having B1, B2, B3, B4). The well layers Q1, Q2, Q3 and Q4 may be formed of a material having a band gap smaller than that of the barrier layers B1, B2, B3 and B4.

A conductive clad layer (not shown) may be formed on or under the active layer 130, and the conductive clad layer (not shown) may be formed of an AlGaN-based semiconductor, rather than a band gap of the active layer 130. It can have a large band gap.

The barrier layers B1, B2, B3, and B4 may be repeatedly stacked with the well layers Q1, Q2, Q3, and Q4. The barrier layers B1, B2, B3, and B4 may be plural in number. The barrier layers B1, B2, B3, and B4 may include indium (In). The barrier layer may comprise In _x Ga ₁ _- _x N (0 <x <1). The barrier layers B1, B2, B3, and B4 may include indium (In), thereby reducing the energy band gap. The barrier layers B1, B2, B3, and B4 have a lower energy barrier, so that holes provided from the second conductivity-type semiconductor layer 150 are provided to all of the well layers Q1, Q2, Q3, and Q4, thereby reducing recombination rate with electrons. It can be maximized.

Indium (In) content of the barrier layers (B1, B2, B3, B4) x may be 0.01 to 0.05. When x, the indium (In) content of the barrier layers (B1, B2, B3, B4) is less than 0.01, the effect of maintaining hole mobility may be halved, and when x is greater than 0.05, the barrier It may be difficult to maintain the shape of the layers B1, B2, B3, B4.

Barrier layers B1, B2, B3, and B4 may be doped with dopants. The dopant may be a p-type dopant and may be, for example, one dopant among magnesium (Mg), zinc (Zn), calcium (Ca), strontium (Sr), or barium (Ba).

2, the light emitting device according to the embodiment may have four barrier layers B1, B2, B3, and B4. The barrier layers B1, B2, B3, and B4 may include a first barrier layer B1, a second barrier layer B2, a third barrier layer B3, and a fourth barrier layer B4. The first barrier layer B1 is disposed on the first conductive semiconductor layer 120, the second barrier layer B2 is disposed on the first barrier layer B1, and the third barrier layer B3 is The fourth barrier layer B4 may be disposed on the second barrier layer B2, and the fourth barrier layer B4 may be disposed on the third barrier layer B3.

The barrier layers B1, B2, B3, and B4 may be plural, and the closer the barrier layers B1, B2, B3, and B4 to the second conductive semiconductor layer 150, the higher the doping concentration. The first barrier layer B1 may have a doping concentration of 1 × 10 ¹⁶ to 1 × 10 ¹⁷ cm ⁻³ , and the second barrier layer B2 may have a doping concentration of 3 × 10 ¹⁶ to 3 × 10 ¹⁷ cm ^-3. The third barrier layer B3 may have a doping concentration of 9 × 10 ¹⁶ to 9 × 10 ¹⁷ cm ⁻³ , and the fourth barrier layer B4 has a doping concentration of 1.5 × 10 ¹⁷ to 1.5 × 10 ^It can be ¹⁸ cm ^-3 .

As described above, when the doping concentration is sequentially increased, an excessive amount of holes may exist in the first conductive semiconductor layer 120 and the adjacent well Q1 layer, and some may escape to the first conductive semiconductor layer 120. Leakage current can be minimized. In addition, the amount of holes transferred to the well layers Q1, Q2, Q3, and Q4 spaced apart from the second conductivity type semiconductor layer 150 may be increased. Therefore, the recombination rate of electrons and holes is increased to improve the light efficiency of the light emitting device.

The thickness d2 of the barrier layer may be 5-10 nm. If the thickness of the barrier layer (d2) is 5 nm or less, the effect of trapping electrons and holes in the well layers (Q1, Q2, Q3, Q4) may be reduced.If the thickness is 10 nm or more, the holes do not pass through the barrier layer. The probability of failure is so great that the rate of recombination of holes and electrons can decrease. Each of the barrier layers may have a different thickness, but is not limited thereto.

The well layers Q1, Q2, Q3, and Q4 may be repeatedly stacked with the barrier layer. The well layers Q1, Q2, Q3, and Q4 may be plural in number. The well layers Q1, Q2, Q3, and Q4 may include indium (In). Well layer (Q1, Q2, Q3, Q4 ) is In _y Ga ₁ _- may include _{y N (0 <y <1} , x <y).

The indium (In) content of the well layers Q1, Q2, Q3, and Q4 may be 0.08 to 0.13. If y, the indium (In) content of the well layers (Q1, Q2, Q3, Q4) is less than 0.08, the energy band gap is so large that the recombination effect of electrons and holes can be slowed, and if y is greater than 0.13, Since the energy band gap is too small, most holes in the well layers Q1, Q2, Q3, and Q4 close to the second conductivity-type semiconductor layer 150 may recombine with electrons, thereby reducing light efficiency.

The thickness d1 of the well layers Q1, Q2, Q3, and Q4 may be 3 to 5 nm. If the thickness (d1) of the well layers (Q1, Q2, Q3, Q4) is 3 nm or less, it is too narrow to reduce the probability of recombination of fast electrons with holes. It can be difficult to grow layers. The plurality of well layers Q1, Q2, Q3, and Q4 may have different thicknesses, but is not limited thereto.

The second conductivity type semiconductor layer 150 may be formed on the active layer 130. The second conductive semiconductor layer 150 may be implemented as a p-type semiconductor layer doped with a p-type dopant. That is, the second conductivity type may be p type. A second conductive semiconductor layer 150 is a semiconductor material having a compositional formula of _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) Example For example, it may be selected from gallium nitride (GaN), aluminum nitride (AlN), aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), indium nitride (InNN), InAlGaN, AlInN, and the like (Mg) and zinc (Zn). ), P-type dopants such as calcium (Ca), strontium (Sr), and barium (Ba) may be doped.

The first conductive semiconductor layer 120, the active layer 130, and the second conductive semiconductor layer 150 may be, for example, metal organic chemical vapor deposition (MOCVD) or chemical vapor deposition (CVD). Deposition), Plasma-Enhanced Chemical Vapor Deposition (PECVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), and the like. It is not limited thereto.

The light emitting structure 160 may have a uniform or non-uniform doping concentration of the conductive dopant in the first conductive semiconductor layer 120 and the second conductive semiconductor layer 150, but is not limited thereto. The interlayer structure of the light emitting structure 160 may be variously formed, but is not limited thereto.

The light emitting structure 160 may include a third semiconductor layer (not shown) having a polarity opposite to that of the second conductive semiconductor layer 150 on the second conductive semiconductor layer 150. In the light emitting structure 160, the first conductivity-type semiconductor layer 120 may be an n-type semiconductor layer, and the second conductivity-type semiconductor layer 150 may be implemented as a p-type semiconductor layer. Accordingly, the light emitting structure 160 may include at least one of an N-P junction, a P-N junction, an N-P-N junction, and a P-N-P junction structure.

Meanwhile, the electron blocking layer 140 may be disposed between the active layer 130 and the second conductive semiconductor layer 150. The electron blocking layer prevents electrons injected from the first conductive semiconductor layer 120 from the first conductive semiconductor layer 120 to the second conductive semiconductor layer 150 without recombination in the active layer 130 when a high current is applied. Can be. The electron blocking layer 140 has a relatively larger energy band gap than the active layer 130, so that electrons injected from the first conductive semiconductor layer 120 do not recombine in the active layer 130, and the second conductive semiconductor layer does not have an energy band gap. The shape injected into the 150 can be prevented. Accordingly, the probability of recombination of electrons and holes in the active layer 130 may be increased and leakage current may be prevented.

The electron blocking layer 140 may have a band gap larger than that of the barrier layer included in the active layer 130, and may be formed of a semiconductor layer including Al such as p-type AlGaN, but is not limited thereto.

Meanwhile, a portion of the active layer 130 and the second conductive semiconductor layer 150 may be removed to expose a portion of the first conductive semiconductor layer 120, and on the exposed first conductive semiconductor layer 120. The first electrode 174 may be formed. That is, the first conductivity type semiconductor layer 120 includes an upper surface facing the active layer 130 and a lower surface facing the substrate 110, and the upper surface includes a region where at least one region is exposed, and the first electrode 174. May be disposed on the exposed area of the top surface.

Meanwhile, a method of exposing a portion of the first conductivity type 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.

In addition, a second electrode 172 may be formed on the second conductivity-type semiconductor layer 150.

Meanwhile, the first electrode 174 and the second electrode 172 are conductive materials such as In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, It may include a metal selected from Ir, W, Ti, Ag, Cr, Mo, Nb, Al, Ni, Cu, and WTi, or may include alloys thereof, and may be formed in a single layer or multiple layers. It is not limited.

3A, 3B, and 3C are diagrams illustrating an energy band gap of the light emitting device 100 according to the embodiment.

Referring to FIG. 3A, the barrier layers B1, B2, B3, and B4 and the well layers Q1, Q2, Q3, and Q4 of the light emitting device according to the exemplary embodiment may have a structure in which a plurality of layers are alternately stacked. The energy band gaps of the two barrier layers B1, B2, B3, and B4 may be the same. The indium content of each barrier layer B1, B2, B3, B4 may be the same.

Referring to FIG. 3B, a plurality of barrier layers of a light emitting device according to another embodiment may be provided, and energy band gaps may be different from each other.

The light emitting device may include at least three barrier layers B1, B2, and B3. For example, the light emitting device may include a first barrier layer B1, a second barrier layer B2, and a third barrier layer B3.

The energy barrier gaps of the first barrier layer B1 and the third barrier layer B3 may be the same, and the second barrier layer B2 may be less than the first barrier layer B1 and the third barrier layer B3. The energy bandgap may be larger.

The first barrier layer B1 and the third barrier layer B3 may have the same indium content, and the second barrier layer B2 may have indium content than the first barrier layer B1 and the third barrier layer B3. This can be lower.

Referring to FIG. 3C, a light emitting device according to another embodiment may include at least three barrier layers B1, B2, and B3. For example, the light emitting device may include a first barrier layer B1, a second barrier layer B2, and a third barrier layer B3.

The energy bandgap of the second barrier layer B2 may be modified to be different from the energy bandgap of the first barrier layer and the third barrier layers B1 and B3 to control or adjust the movement of carriers. The energy band gap of the second barrier layer B2 may be adjusted to maximize the overlap of the wave function of electrons and holes. This may increase the recombination rate of electrons and holes and improve the internal quantum efficiency (IQE).

The energy band gaps of the well layers Q1, Q2, and Q3 may be the same. Indium contents of the plurality of well layers Q1, Q2, and Q3 may be the same. By equalizing the energy band gaps of the well layers Q1, Q2, and Q3, the wavelengths of light generated by recombination of electrons and holes in the well layers Q1, Q2, and Q3 may be the same.

4 is a view illustrating a light emitting device according to an embodiment, and FIG. 5 is an enlarged cross-sectional view of a portion B of the light emitting device 100 of FIG. 4. However, the above-described matters will not be further explained in detail.

Referring to FIG. 4, the light emitting device 200 according to the embodiment may include a substrate 210, a first electrode layer 220 disposed on the substrate 210, and a second conductive semiconductor layer doped with a second conductivity type. 230, an active layer 250, and a light emitting structure 270 including a first conductive semiconductor layer 260 doped with a first conductivity type, and a second electrode layer 282.

The substrate 210 may be formed using a material having excellent thermal conductivity, and may also be formed of a conductive material, and may be formed using a metal material or a conductive ceramic. The substrate 210 may be formed of a single layer and may be formed of a dual structure or multiple structures.

That is, the substrate 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. It can be formed by stacking materials. In addition, the substrate 210 may be formed of Si, Ge, GaAs, ZnO, SiC, SiGe, GaN, Ga ₂ O ₃ It may be implemented as a carrier wafer such as.

The substrate 210 may facilitate the emission of heat generated from the light emitting device 200, thereby improving the thermal stability of the light emitting device 200.

The first electrode layer 220 may be formed on the substrate 210, and the first electrode layer 220 may be an ohmic layer (not shown), a reflective layer (not shown), or a bonding layer (not shown). At least one layer of a bonding layer (not shown) may be included. For example, the first electrode layer 220 may be a structure of an ohmic layer / a reflection layer / a bonding layer, a laminate structure of an ohmic layer / a reflection layer, or a structure of a reflection layer (including an ohmic layer) / a bonding layer. For example, the first electrode layer 220 may have a form in which a reflective layer (not shown) and an ohmic layer (not shown) are sequentially stacked on the insulating layer.

The reflective layer (not shown) may be disposed between the ohmic layer (not shown) and the insulating layer (not shown), and have excellent reflective properties such as Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg , Zn, Pt, Au, Hf, or a combination of these materials, or a combination of these materials or IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, to form a multi-layer using a transparent conductive material such as Can be. Further, the reflective layer (not shown) can be laminated with IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni and the like. In addition, when the reflective layer (not shown) is formed of a material in ohmic contact with the light emitting structure 270 (eg, the second conductivity type semiconductor layer 230), the ohmic layer (not shown) may not be separately formed. It is not limited to.

The ohmic layer (not shown) is in ohmic contact with the bottom surface of the light emitting structure 270, 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 for smoothly injecting the carrier into the second conductivity-type semiconductor layer 230 and is not necessarily formed.

The first electrode layer 220 may include a bonding layer (not shown), and the bonding layer 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 270 may include at least a second conductivity type semiconductor layer 230, an active layer 250, and a first conductivity type semiconductor layer 260, and include the second conductivity type semiconductor layer 230 and the first conductivity. The active layer 250 may be disposed between the type semiconductor layers 260.

A second conductivity type semiconductor layer 230 may be formed on the first electrode layer 220. The second conductive semiconductor layer 230 may be implemented as a p-type semiconductor layer doped with a p-type dopant. That is, the second conductivity type may be p type. The p-type semiconductor layer contains a semiconductor material, for example, having a compositional formula of _{In x Al y Ga 1 -x- y} N (0 = x = 1, 0 = y = 1, 0 = x + y = 1) GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN and the like may be selected, and p-type dopants such as Mg, Zn, Ca, Sr, and Ba may be doped.

The active layer 250 may be formed on the second conductive semiconductor layer 230. The active layer 250 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.

Well active layer 250 has a composition formula in this case formed of a quantum well structure, for _{example, In x Al y Ga 1 -x-} y N (0 = x = 1, 0 = y = 1, 0 = x + y = 1) Barrier layer having a compositional formula of layers Q1, Q2, Q3, Q4 and In _a Al _b Ga ₁ _-a- _b N (0 = a = 1, 0 = b = 1, 0 = a + b = 1) It may have a single or quantum well structure having B1, B2, B3, B4). The well layers Q1, Q2, Q3, and Q4 may be formed of a material having a band gap smaller than that of the barrier layers B1, B2, B3, and B4.

In addition, when the active layer 250 has a multi-quantum well structure, each of the well layers Q1, Q2, Q3, and Q4 may have different In contents, different band gaps, and different thicknesses, but is not limited thereto. No.

The barrier layers B1, B2, B3, and B4 may be repeatedly stacked with the well layers Q1, Q2, Q3, and Q4. The barrier layers B1, B2, B3, and B4 may be plural in number. The barrier layers B1, B2, B3, and B4 may include indium (In). The barrier layer may comprise In _x Ga ₁ _- _x N (0 <x <1). The barrier layers B1, B2, B3, and B4 may include indium (In), thereby reducing the energy band gap. The barrier layers B1, B2, B3, and B4 have a lower energy barrier, so that holes provided from the second conductivity-type semiconductor layer 230 are provided to all of the well layers Q1, Q2, Q3, and Q4 to improve recombination rate with electrons. It can be maximized.

Referring to FIG. 5, the light emitting device 200 according to the embodiment may have four barrier layers B1, B2, B3, and B4. The barrier layers B1, B2, B3, and B4 may include a first barrier layer B1, a second barrier layer B2, a third barrier layer B3, and a fourth barrier layer B4. The fourth barrier layer B4 is disposed on the second conductivity type semiconductor layer 230, the third barrier layer B3 is disposed on the fourth barrier layer B4, and the second barrier layer B2 is The first barrier layer B3 may be disposed on the third barrier layer B3, and the first barrier layer B1 may be disposed on the second barrier layer B2.

The barrier layers B1, B2, B3, and B4 may be plural, and the closer the barrier layers B1, B2, B3, and B4 are to the second conductivity type semiconductor layer 230, the higher the doping concentration may be. The first barrier layer B1 may have a doping concentration of 1 × 10 ¹⁶ to 1 × 10 ¹⁷ cm ⁻³ , and the second barrier layer B2 may have a doping concentration of 3 × 10 ¹⁶ to 3 × 10 ¹⁷ cm ^-3. The third barrier layer B3 may have a doping concentration of 9 × 10 ¹⁶ to 9 × 10 ¹⁷ cm ⁻³ , and the fourth barrier layer B4 has a doping concentration of 1.5 × 10 ¹⁷ to 1.5 × 10 ^It can be ¹⁸ cm ^-3 .

If the doping concentration is sequentially increased as described above, an excessive amount of holes may exist in the first conductive semiconductor layer 260 and the adjacent well Q1 layer, and some may escape to the first conductive semiconductor layer 260. Leakage current can be minimized. In addition, the amount of holes transferred to the well layers Q1, Q2, Q3, and Q4 spaced apart from the second conductivity type semiconductor layer 230, for example, the first well layer Q1, may be increased. Therefore, the recombination rate of electrons and holes is increased to improve the light efficiency of the light emitting device.

The thickness d2 of the barrier layers B1, B2, B3, and B4 may be 5 to 10 nm. When the thickness d2 of the barrier layers B1, B2, B3, and B4 is 5 nm or less, the effect of trapping electrons and holes in the well layers Q1, Q2, Q3, and Q4 may be reduced, and the thickness may be 10 nm or more. In this case, the probability that the hole does not pass through the barrier layers B1, B2, B3, and B4 is too high, which may reduce the recombination rate of the hole and the electron. The barrier layers B1, B2, B3, and B4 may have different thicknesses, but the thickness of the barrier layers B1, B2, B3, and B4 is not limited thereto.

The well layers Q1, Q2, Q3, and Q4 may be repeatedly stacked with the barrier layers B1, B2, B3, and B4. The well layers Q1, Q2, Q3, and Q4 may be plural in number. The well layers Q1, Q2, Q3, and Q4 may include indium (In). Well layer (Q1, Q2, Q3, Q4 ) is In _y Ga ₁ _- may include _{y N (0 <y <1} , x <y).

The indium (In) content of the well layers Q1, Q2, Q3, and Q4 may be 0.08 to 0.13. If y, the indium (In) content of the well layers (Q1, Q2, Q3, Q4) is less than 0.08, the energy band gap is so large that the recombination effect of electrons and holes can be slowed, and if y is greater than 0.13, Since the energy band gap is too small, most holes in the well layers Q1, Q2, Q3, and Q4 close to the second conductivity-type semiconductor layer 230 may recombine with electrons, thereby reducing light efficiency.

A conductive clad layer (not shown) may be formed on and / or below the active layer 250. 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 250.

Meanwhile, an electron blocking layer 240 may be formed between the active layer 250 and the second conductive semiconductor layer 230, and the electron blocking layer 240 may be formed from the first conductive semiconductor layer 260 when a high current is applied. The electron injected into the active layer 250 may be an electron blocking layer that prevents electrons from flowing into the second conductive semiconductor layer 230 without recombination in the active layer 250. The intermediate layer (not shown) has a band gap relatively larger than that of the active layer 250, so that electrons injected from the first conductive semiconductor layer 260 are not recombined in the active layer 250, and the second conductive semiconductor layer 230 is not. ) Can be prevented. Accordingly, the probability of recombination of electrons and holes in the active layer 250 can be increased and leakage current can be prevented.

Meanwhile, the above-described electron blocking layer 240 may have a bandgap larger than the bandgap of the barrier layer included in the active layer 250, and may be formed of a semiconductor layer including Al such as p-type AlGaN. Not.

The first conductivity type semiconductor layer 260 may be formed on the active layer 250. The first conductivity-type semiconductor layer 260 may be implemented as an n-type semiconductor layer, the n-type semiconductor layer is, for example, In _x Al _y Ga _1-xy N (0≤x≤1, 0≤y≤1, 0 ≦ x + y ≦ 1), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, and the like, and for example, Si, Ge, Sn, Se, Te and The same n-type dopant may be doped.

A second electrode layer 282 electrically connected to the first conductive semiconductor layer 260 may be formed on the first conductive semiconductor layer 260, and the second electrode layer 282 may include at least one pad or / and a predetermined shape. It may include an electrode having a pattern. The second electrode layer 282 may be disposed in the center region, the outer region, or the corner region of the upper surface of the first conductivity type semiconductor layer 260, but is not limited thereto. The second electrode layer 282 may be disposed in a region other than the first conductive semiconductor layer 260, but is not limited thereto.

The second electrode layer 282 may be a conductive material, for example, In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, W, Ti, Ag, It can be formed in a single layer or multiple layers using a metal or alloy selected from Cr, Mo, Nb, Al, Ni, Cu, and WTi.

The light emitting structure 270 may include a third semiconductor layer (not shown) having a polarity opposite to that of the first conductive semiconductor layer 260 on the first conductive semiconductor layer 260. In addition, the second conductivity-type semiconductor layer 230 may be an n-type semiconductor layer, and the first conductivity-type semiconductor layer 260 may be implemented as a p-type semiconductor layer. Accordingly, the light emitting structure layer 270 may include at least one of an N-P junction, a P-N junction, an N-P-N junction, and a P-N-P junction structure.

A light extracting structure 284 may be formed on the upper portion of the light emitting structure 270.

The light extracting structure 270 is formed on the upper surface of the first conductivity type semiconductor layer 260, or after the light transmitting electrode layer (not shown) is formed on the light emitting structure 270, and then on the light transmitting electrode layer (not shown). It may be formed, but is not limited thereto.

The light extracting structure 284 may be formed in a part or the entire area of the light transmissive electrode layer (not shown) or the upper surface of the first conductivity type semiconductor layer 260. The light extracting structure 284 may be formed by performing etching on at least one region of the light transmissive electrode layer (not shown) or the upper surface of the first conductive semiconductor layer 260, but is not limited thereto. The etching process may include a wet or / and dry etching process, and as the etching process is performed, the top surface of the light transmissive electrode layer (not shown) or the top surface of the first conductive semiconductor layer 260 may be formed using the light extraction structure 284. Roughness may be included. 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. As the light extracting structure 284 is formed on the light transmissive electrode layer (not shown) or on the top surface of the first conductivity type semiconductor layer 260, the light generated from the active layer 250 is transmitted to the light transmissive electrode layer (not shown) or the first. Since total reflection from the upper surface of the conductive semiconductor layer 260 may be prevented from being resorbed or scattered, it may contribute to the improvement of light extraction efficiency of the light emitting device 200.

Passivation (not shown) may be formed on side and upper regions of the light emitting structure 270, and passivation (not shown) may be formed of an insulating material.

FIG. 6 is a graph illustrating internal quantum efficiency (IQE) according to current of a light emitting device.

Referring to FIG. 6, in the active layer, the barrier layer includes undoped GaN, and the well layer includes internal quantum efficiency (b) according to the current of the light emitting device including InGaN and internal quantum according to the current of the light emitting device according to the embodiment. Efficiency (a) can be compared.

In the light emitting device according to the embodiment, it can be seen that the barrier layer in the low current region has superior internal quantum efficiency than the light emitting device including undoped GaN.

7A is a perspective view illustrating a light emitting device package 300 according to an embodiment of the present invention, and FIG. 7B is a cross-sectional view illustrating a cross section of the light emitting device package 300 according to another embodiment.

7A and 7B, the light emitting device package 300 according to the embodiment includes a body 310 having a cavity formed therein, and first and second electrodes 340 and 350 mounted on the body 310. The light emitting device 320 electrically connected to the two electrodes and the encapsulant 330 formed in the cavity may be included, and the encapsulant 330 may include a phosphor (not shown).

The body 310 may be made of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), photo sensitive glass (PSG), polyamide 9T ), new geo-isotactic polystyrene (SPS), metal materials, sapphire (Al ₂ O _3), beryllium oxide (BeO), is a printed circuit board (PCB, printed circuit board), it may be formed of at least one of ceramic. The body 310 may be formed by injection molding, etching, or the like, but is not limited thereto.

The inner surface of the body 310 may be formed with an inclined surface. The reflection angle of the light emitted from the light emitting device 320 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 adjusted.

The shape of the cavity formed in the body 310 as viewed from above may be circular, rectangular, polygonal, elliptical, or the like, and in particular, may have a curved shape, but is not limited thereto.

The encapsulant 330 may be filled in the cavity and may include a phosphor (not shown). The encapsulant 330 may be formed of transparent silicone, epoxy, and other resin materials. The encapsulant 330 may be formed in such a manner that the encapsulant 330 is filled in the cavity and then cured by ultraviolet rays or heat.

The phosphor (not shown) may be selected according to the wavelength of the light emitted from the light emitting device 320 to allow the light emitting device package 300 to realize white light.

The fluorescent material (not shown) included in the encapsulant 330 may be a blue light emitting phosphor, a blue light emitting fluorescent material, a green light emitting fluorescent material, a yellow green light emitting fluorescent material, a yellow light emitting fluorescent material, Fluorescent material, orange light-emitting fluorescent material, and red light-emitting fluorescent material may be applied.

The phosphor (not shown) may be excited by the light having the first light emitted from the light emitting device 320 to generate the second light. For example, when the light emitting element 320 is a blue light emitting diode and the phosphor (not shown) is a yellow phosphor, the yellow phosphor may be excited by blue light to emit yellow light, and blue light emitted from the blue light emitting diode As the yellow light generated by excitation by blue light is mixed, the light emitting device package 300 can provide white light.

When the light emitting device 320 is a green light emitting diode, a magenta phosphor or a blue and red phosphor (not shown) is mixed. When the light emitting device 320 is a red light emitting diode, a cyan phosphor or a blue and green phosphor is mixed. For example,

The phosphor (not shown) may be a known one such as YAG, TAG, sulfide, silicate, aluminate, nitride, carbide, nitridosilicate, borate, fluoride, or phosphate.

The first electrode 340 and the second electrode 350 may be mounted on the body 310. The first electrode 340 and the second electrode 350 may be electrically connected to the light emitting device 320 to supply power to the light emitting device 320.

The first electrode 340 and the second electrode 350 are electrically separated from each other and reflect light generated from the light emitting device 320 to increase light efficiency. The first electrode 340 and the second electrode 350 may discharge heat generated from the light emitting device 320 to the outside.

In FIG. 7B, the light emitting device 320 is mounted on the first electrode 340, but is not limited thereto. The light emitting device 320, the first electrode 340, and the second electrode 350 may be wire bonded. May be electrically connected by any one of the following methods, a flip chip method, and a die bonding method.

The first electrode 340 and the second electrode 350 may be formed of a metal material such as titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chromium (Cr), tantalum ), Platinum (Pt), tin (Sn), silver (Ag), phosphorous (P), aluminum (Al), indium (In), palladium (Pd), cobalt ), Hafnium (Hf), ruthenium (Ru), and iron (Fe). The first electrode 340 and the second electrode 350 may have a single-layer structure or a multi-layer structure, but the present invention is not limited thereto.

The light emitting device 320 is mounted on the first electrode 340 and may be a light emitting device that emits light such as red, green, blue, or white, or a UV (Ultra Violet) However, the present invention is not limited thereto. One or more light emitting devices 320 may be mounted.

The light emitting device 320 is applicable to both a horizontal type whose electrical terminals are all formed on the upper surface, a vertical type formed on the upper and lower surfaces, or a flip chip.

The light emitting device package 300 may include a light emitting device.

The light emitting device 320 may be p-doped such that the barrier layer (not shown) includes indium (In) and the plurality of barrier layers (not shown) have different doping concentrations. The light emitting device 320 includes a plurality of barrier layers (not shown) including indium (In) and p-doped so as to maintain the mobility of holes provided from the second conductive semiconductor layer (not shown). Can provide a hole.

The light emitting device 320 including the barrier layer (not shown) may be included to maximize reliability and light extraction amount of the light emitting device package 300.

A light guide plate, a prism sheet, a diffusion sheet, and the like, which are optical members, may be disposed on a light path of the light emitting device package 300.

The light emitting device package 300, the substrate, and the optical member may function as a light unit. Another embodiment may be implemented as a display device, an indicating device, a lighting system including a light emitting device (not shown) or a light emitting device package 300, for example, the lighting system may include a lamp, a streetlight .

8A is a perspective view illustrating a lighting system 400 including a light emitting device according to an embodiment, and FIG. 8B is a cross-sectional view taken along line D-D 'of the lighting system of FIG. 8A.

8B is a cross-sectional view of the illumination system 400 of FIG. 8A cut in the longitudinal direction Z and the height direction X and viewed in the horizontal direction Y. FIG.

8A and 8B, the illumination system 400 may include a body 410, a cover 430 coupled to the body 410, and a finishing cap 450 positioned at opposite ends of the body 410 have.

The lower surface of the body 410 is fastened to the light emitting device module 443, the body 410 is conductive and so that the heat generated from the light emitting device package 444 can be discharged to the outside through the upper surface of the body 410 The heat dissipation effect may be formed of an excellent metal material, but is not limited thereto.

The light emitting device package 444 may include a light emitting device (not shown).

The light emitting device (not shown) may be p-doped such that the barrier layer (not shown) includes indium (In) and the plurality of barrier layers (not shown) have different doping concentrations. In the light emitting device (not shown), a plurality of barrier layers (not shown) include indium (In) and are p-doped to maintain the mobility of holes provided in the second conductivity type semiconductor layer (not shown). Hole) can be provided.

Including a light emitting device (not shown) including the barrier layer (not shown), it is possible to maximize the reliability and light extraction amount of the light emitting device package 444 and the lighting system 400.

The light emitting device package 444 may be mounted on the substrate 442 in multiple colors and in multiple rows to form a module. The light emitting device package 444 may be mounted at the same interval or may be mounted at various separation distances as necessary to adjust brightness. As the substrate 442, a metal core PCB (MCPCB) or a PCB made of FR4 may be used.

The cover 430 may be formed in a circular shape to surround the lower surface of the body 410, but is not limited thereto.

The cover 430 may protect the light emitting device module 443 from the foreign matters. The cover 430 may include diffusing particles to prevent glare of light generated from the light emitting device package 444 and to uniformly emit light to the outside, and may also include at least one of an inner surface and an outer surface of the cover 430. A prism pattern or the like may be formed on the surface. In addition, a phosphor may be applied to at least one of an inner surface and an outer surface of the cover 430.

Since the light generated from the light emitting device package 444 is emitted to the outside through the cover 430, the cover 430 should be excellent in light transmittance, and sufficient heat resistance to withstand the heat generated from the light emitting device package 444. It should be provided, the cover 430 may be formed of a material including polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), etc. have.

Closing cap 450 is located at both ends of the body 410 may be used for sealing the power supply (not shown). Power cap 452 is formed in the closing cap 450, the lighting system 400 according to the embodiment can be used immediately without a separate device to the terminal from which the existing fluorescent lamps are removed.

9 is an exploded perspective view of a liquid crystal display including a light emitting device according to an embodiment.

9 is an edge-light method, and the liquid crystal display 500 may include a liquid crystal display panel 510 and a backlight unit 570 for providing light to the liquid crystal display panel 510.

The liquid crystal display panel 510 may display an image by using light provided from the backlight unit 570. The liquid crystal display panel 510 may include a color filter substrate 512 and a thin film transistor substrate 514 facing each other with a liquid crystal interposed therebetween.

The color filter substrate 512 may implement colors of an image displayed through the liquid crystal display panel 510.

The thin film transistor substrate 514 is electrically connected to the printed circuit board 518 on which a plurality of circuit components are mounted through the driving film 517. The thin film transistor substrate 514 may apply a driving voltage provided from the printed circuit board 518 to the liquid crystal in response to a driving signal provided from the printed circuit board 518.

The thin film transistor substrate 514 may include a thin film transistor and a pixel electrode formed of a thin film on another substrate of a transparent material such as glass or plastic.

The backlight unit 570 may convert the light provided from the light emitting device module 520, the light emitting device module 520 into a surface light source, and provide the light guide plate 530 to the liquid crystal display panel 510. Reflective sheet for reflecting the light emitted from the rear of the light guide plate 530 and the plurality of films 550, 560, 564 to uniform the luminance distribution of the light provided from the 530 and improve the vertical incidence ( 540.

The light emitting device module 520 may include a printed circuit board 522 such that a plurality of light emitting device packages 524 and a plurality of light emitting device packages 524 are mounted to form a module.

The light emitting device package 524 may include a light emitting device.

Including a light emitting device (not shown) including the barrier layer (not shown) can maximize the reliability and light extraction of the light emitting device package 524 and the backlight unit 570.

The backlight unit 570 includes a diffusion film 566 for diffusing light incident from the light guide plate 530 toward the liquid crystal display panel 510 and a prism film 550 for condensing the diffused light to improve vertical incidence. It may be configured, and may include a protective film 564 for protecting the prism film 550.

10 is an exploded perspective view of a liquid crystal display device including a light emitting device according to an embodiment. However, the parts shown and described in FIG. 9 will not be described in detail repeatedly.

10 illustrates a liquid crystal display 600 of a direct type according to an embodiment. The liquid crystal display 600 may include a liquid crystal display panel 610 and a backlight unit 670 for providing light to the liquid crystal display panel 610. Since the liquid crystal display panel 610 is the same as that described with reference to FIG. 11, a detailed description thereof will be omitted.

The backlight unit 670 may include a plurality of light emitting device modules 623, a reflective sheet 624, a lower chassis 630 in which the light emitting device modules 623 and the reflective sheet 624 are accommodated, and an upper portion of the light emitting device module 623. It may include a diffusion plate 640 and a plurality of optical film 660 disposed in the.

The light emitting device module 623 may include a printed circuit board 621 such that a plurality of light emitting device packages 622 and a plurality of light emitting device packages 622 may be mounted to form a module.

The light emitting device package 622 may include a light emitting device.

Including a light emitting device (not shown) including the barrier layer (not shown), the reliability and light extraction amount of the light emitting device package 622 and the backlight unit 670 may be maximized.

The reflective sheet 624 reflects the light generated from the light emitting device package 622 in the direction in which the liquid crystal display panel 610 is positioned to improve light utilization efficiency.

Light generated by the light emitting device module 623 is incident on the diffusion plate 640, and the optical film 660 is disposed on the diffusion plate 640. The optical film 660 includes a diffusion film 666, a prism film 650, and a protective film 664.

The configuration and the method of the embodiments described above are not limitedly applied, but the embodiments may be modified so that all or some of the embodiments are selectively combined so that various modifications can be made. .

Although the preferred embodiments have been illustrated and described above, the invention is not limited to the specific embodiments described above, and does not depart from the gist of the invention as claimed in the claims. Various modifications can be made by the person who has them, and these modifications should not be understood individually from the technical idea or the prospect of the present invention.

110 substrate 120 first conductive semiconductor layer
130: active layer 140: electron blocking layer
150: second conductive semiconductor layer 160: light emitting structure
172: second electrode 174: first electrode
300: light emitting device package.

Claims

A first conductive semiconductor layer doped with a first conductive type;
An active layer of a multi-quantum well structure (MQW) disposed on the first conductivity type semiconductor layer and including a plurality of well layers and a barrier layer;
And a second conductive semiconductor layer disposed on the active layer and doped with a second conductive type.
Each of the plurality of barrier layers is doped to the second conductivity type, and the doping concentration of the barrier layer increases toward the second conductivity type semiconductor layer.

The method of claim 1,
The second conductivity type p-type light emitting device.

The method of claim 1,
The barrier layer comprises at least four first barrier layers, a second barrier layer, a third barrier layer, and a fourth barrier layer,
A light emitting element ^3, the ^first barrier layer is 10 × ¹⁶ is the doping concentration to 1 10 ¹⁷ cm × 1.

The method of claim 3,
The fourth barrier layer is the doping concentration of 1.5 × 10 ¹⁷ to 1.5 × 10 ¹⁸ cm ^- ³ in the light emitting device.

5. The method of claim 4,
And ^3, ^wherein the second barrier layer is that the doping concentration of 3 × 10 ¹⁶ to 3 × 10 ¹⁷ cm
The third barrier layer the doping concentration of 9 × 10 ¹⁶ to 9 × 10 ¹⁷ cm ^- ³ in the light emitting device.

The method of claim 1,
The barrier layer includes indium (In).

The method according to claim 6,
The barrier layer includes In _x Ga ₁ _- _x N (0 <x <1).

The method of claim 7, wherein
X is 0.01 to 0.05.

The method of claim 7, wherein
The well layer includes In _y Ga ₁ _- _y N (0 <y <1, x <y).

10. The method of claim 9,
Y is 0.08 to 0.13.

The method of claim 10,
The well layer has a thickness of 3 to 5nm, the barrier layer has a thickness of 5 to 10nm.

The method of claim 1,
The barrier layers have different energy band gaps.

The method of claim 1,
The barrier layer includes at least three first barrier layers, a second barrier layer, and a third barrier layer, wherein the second barrier layer has an energy bandgap of energy bands of the first barrier layer and the third barrier layer. Light emitting element smaller than the gap.

The method of claim 1,
The barrier layer includes at least three first barrier layers, a second barrier layer, and a third barrier layer, wherein the second barrier layer has an energy bandgap of energy bands of the first barrier layer and the third barrier layer. Light emitting element larger than the gap.

The method of claim 1,
The well layer is a plurality,
A light emitting device in which the plurality of well layers have the same energy band gap.