KR20130080298A

KR20130080298A - Light emitting device

Info

Publication number: KR20130080298A
Application number: KR1020120001130A
Authority: KR
Inventors: 심상균; 강동훈
Original assignee: 엘지이노텍 주식회사
Priority date: 2012-01-04
Filing date: 2012-01-04
Publication date: 2013-07-12

Abstract

PURPOSE: A light emitting device is provided to improve the intensity of light by controlling the composition of Al or In on an electron blocking layer. CONSTITUTION: An active layer (114) is formed on a first conductive semiconductor layer. The active layer includes a quantum well (114a) and a quantum wall (114b). An electron blocking layer (126) is formed on the active layer. The electron blocking layer includes a first electron blocking layer (126a), a second electron blocking layer (126b), and a third electron blocking layer (126c). The first electron blocking layer has an energy band gap over the energy band gap of the quantum wall. The third electron blocking layer has an energy band gap over the energy band gap of the first electron blocking layer.

Description

[0001] LIGHT EMITTING DEVICE [0002]

Embodiments relate to a light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system.

A light emitting device is a device in which electrical energy is converted into light energy. For example, the LED can realize various colors by adjusting the composition ratio of the compound semiconductor.

The nitride semiconductor thin film-based light emitting device has advantages of low power consumption, semi-permanent life, fast response speed, safety, and environmental friendliness compared to conventional light sources such as fluorescent and incandescent lamps. Therefore, LED backlights that replace the Cold Cathode Fluorescence Lamp (CCFL), which forms the backlight of liquid crystal display (LCD) displays, white LED lighting devices that can replace fluorescent or incandescent bulbs, and automotive headlights. And the application is expanding to traffic lights.

Increasing the application range of nitride semiconductor light emitting device basically requires the development of high power and high efficiency technology of the light emitting device.

On the other hand, according to the prior art, in the nitride semiconductor light emitting device having the multi-quantum well structure active layer, all the quantum well layers in the active layer cannot uniformly disperse the injected carriers, and only a few quantum well layers adjacent to the hole injection layer are provided. There is a problem that mainly contributes to light emission. Therefore, when the amount of injection current is large enough, excess electrons are generated which are not effectively bound in the active layer.

These excess electrons do not participate in generating light and self-dissipate in the active layer or leak out of the active layer.

Leakage out of the active layer occurs mainly in the form of a quantum barrier overflow of injected carrier.

In addition, in the conventional nitride semiconductor light emitting device, electrons injected into the active layer have a hot carrier property and thus have a serious carrier overflow problem.

As a result, when the injected current is increased, the non-luminescence loss of electrons and holes is increased, so that the luminous efficiency of the active layer, for example, the internal quantum efficiency is seriously reduced.

Accordingly, according to the related art, an electron blocking layer is formed between the P-GaN layer and the active layer. The electron blocking layer has a larger energy band gap than the quantum wall of the active layer to block electrons supplied from the N-GaN layer from passing through the active layer to the P-GaN layer without participating in light emission.

On the other hand, according to the prior art, the electron blocking layer has a P-AlGaN layer, but the hole injection (Hole injection) is not properly, the recombination rate (low recombination rate) is lowered, the brightness is improved and the operating voltage is adversely affected.

Embodiments provide a light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system capable of improving brightness and improving an operating voltage.

A light emitting device according to an embodiment includes a first conductive semiconductor layer; An active layer formed on the first conductivity type semiconductor layer including a quantum well and a quantum wall; An electron blocking layer on the active layer; And a second conductive semiconductor layer on the electron blocking layer, wherein the electron blocking layer comprises: a first electron blocking layer having an energy band gap greater than or equal to that of the quantum wall; And a second electron blocking layer on the first electron blocking layer in which an energy band gap gradually decreases from the active layer toward the second conductive semiconductor layer.

According to the light emitting device, the manufacturing method of the light emitting device, the light emitting device package, and the lighting system according to the embodiment, the brightness and the operating voltage can be improved by controlling the Al or In composition of the electron blocking layer.

1 is a cross-sectional view of a light emitting device according to an embodiment.
2 is an exemplary energy band diagram of a light emitting device according to the embodiment;
3 is a diagram illustrating an energy band level simulation of a light emitting device according to an embodiment.
Figure 4 is an exemplary energy band level simulation of a light emitting device according to the prior art.
5 is a diagram illustrating an internal quantum efficiency of the light emitting device according to the embodiment.
6 to 8 are cross-sectional views of a method of manufacturing a light emitting device according to the embodiment.
9 is a cross-sectional view of a light emitting device package according to the embodiment.
10 is a perspective view of a lighting unit according to an embodiment.
11 is a perspective view of a backlight unit according to an embodiment.

In the description of the embodiments, it is to be understood that each layer (film), area, pattern or structure may be referred to as being "on" or "under" the substrate, each layer Quot; on "and" under "are intended to include both" directly "or" indirectly " do. Also, the criteria for top, bottom, or bottom of 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.

(Example)

1 is a cross-sectional view of a light emitting device 100 according to an embodiment, FIG. 2 is a diagram illustrating an energy band diagram of a light emitting device according to an embodiment, and FIG. 3 is an energy band level simulation example of a light emitting device according to an embodiment. It is also. 1 illustrates a horizontal light emitting device, but the embodiment is not limited thereto.

The light emitting device 100 according to the embodiment includes a first conductive semiconductor layer 112, an active layer formed on the first conductive semiconductor layer 112 including a quantum well 114a and a quantum wall 114b. 114, an electron blocking layer 126 on the active layer 114, and a second conductivity-type semiconductor layer 116 on the electron blocking layer 126.

In order to solve the above problems, the embodiment may control the Al composition during the growth of the electron blocking layer to improve the droop phenomenon of the efficiency and increase the light extraction efficiency.

For example, in the exemplary embodiment, the electron blocking layer 126 is disposed on the first electron blocking layer 126a and the first electron blocking layer 126a having an energy band gap greater than or equal to the energy band gap of the quantum wall 114b. The second electron blocking layer 126b may gradually include an energy band gap in the active layer 114 toward the second conductive semiconductor layer 116.

In an embodiment, the maximum value of the energy band gap of the second electron blocking layer 126b may be greater than the energy band gap of the first electron blocking layer 126a.

According to an embodiment, the third electron blocking layer 126c may have an energy band gap greater than or equal to an energy band gap of the first electron blocking layer 126a between the first electron blocking layer 126a and the second electron blocking layer 126b. ) May be further included.

The first electron blocking layer 126a includes Al _x1 In _y1 Ga _(1-x1- _y1 ₎ N (where 0 ≦ x1 ≦ ₁ , 0 ≦ _y1 ≦ 1), and the second electron blocking layer 126b. ) Includes Al _x2 In _y2 Ga _(1-x2- _y2 ₎ N (where 0 ≦ _x2 ≦ 1 and 0 ≦ _y2 ≦ 1), and the composition of Al of the second electron blocking layer 126b (x2) May gradually decrease from the active layer 114 toward the second conductivity-type semiconductor layer 116.

For example, the first electron blocking layer 126a may have Al _x1 In _y1 Ga _(1-x1- _y1 ₎ N (where 0 ≦ x1 ≦ ₁ and 0 ≦ y1 ≦ 1). 0.01 <y1 <0.2, the thickness may be about 0.5 ~ 3nm but is not limited thereto. In this case, the content (x1) of Al of the first electron blocking layer 126a may be 0.1 <x1 <0.2, but is not limited thereto. When the Al content (x1) of the first electron blocking layer 126a is 0.1 or less, damage may be caused to the active layer 114 by Mg back diffusion, and when 0.2 or more, the hole is an active layer ( The injection rate into 114 can be reduced.

In addition, the second electron blocking layer 126b has Al _{x 2} In _{y 2} Ga _(1- _x _2- _{y 2} ₎ N (where ₀ _{≦ x 2 ≦} ₁ and 0 ≦ y 2 ≤ 1), and the In content (y 2) is 0.01 < It may be y1 <0.2, the Al content (x2) of the second electron blocking layer 126b may be 0.1 <x2 <0.2, but is not limited thereto.

In this case, the composition (x2) of Al of the second electron blocking layer 126b may gradually decrease from the active layer 114 toward the second conductive semiconductor layer 116.

In addition, the composition (y2) of In of the second electron blocking layer 126b may gradually increase from the active layer 114 toward the second conductive semiconductor layer 116.

Accordingly, according to the embodiment, the In, Al, Ga can be flowed to give the composition a grading, thereby increasing the hole injection efficiency.

In an embodiment, the composition (x2) of Al of the second electron blocking layer 126b may be higher than the composition (x1) of Al of the first electron blocking layer 126a, and the second electron blocking layer 126b may be In. The composition (y2) may be lower than the In composition (y1) of the first electron blocking layer 126a, but is not limited thereto.

For example, the third electron blocking layer 126c may have an In composition (y3) of Al _x3 In _y3 Ga _(1-x3- _y3 ₎ N (where 0 _≦ _x3 _{≦ 1 and 0 ≦} _y3 _{≦ 1} ). It may be <y3 <0.1, the composition of Al (x3) may be 0.15 <x3 <0.3, the thickness may be about 0.5nm ~ 3nm, but is not limited thereto. If the Al composition (x3) of the third electron blocking layer 126c is 0.15 or less, the electron blocking may not function properly. If 0.2 or more, the hole is injected into the active layer. rate can be reduced.

3 is a diagram illustrating an energy band level simulation of a light emitting device according to an embodiment, FIG. 4 is a diagram illustrating an energy band level simulation of a light emitting device according to the prior art, and FIG. 5 is a diagram illustrating an internal quantum efficiency of a light emitting device according to an embodiment. It is also.

According to the embodiment, when the grade is formed in the electron blocking layer 126 so as to gradually reduce the energy band gap in the direction of the second conductive type semiconductor layer from the active layer by controlling Al composition or In composition, Injection can be good.

For example, according to the embodiment, tunneling may occur in the conduction band Ec of the electron blocking layer 126, and the level of the household appliance conductor Ev is lower than in the prior art, thereby reducing the energy barrier. Due to this, the injection rate of holes may increase.

In the prior art, a region in which the energy band gap rapidly changes between the second conductive semiconductor layer and the electron blocking layer forms a kink, and as the kink is high and low, hole movement may be affected.

Meanwhile, according to the exemplary embodiment, as the energy band gap of the second electron blocking layer 126b is gradually reduced in the direction of the second conductive type semiconductor layer 116 from the active layer 114, holes are injected ( hole injection)

Accordingly, according to the embodiment S as shown in FIG. 5, it can be seen that the internal quantum efficiency IQE increases with an increase in the applied voltage V, compared to the prior art Ref. Can increase the extraction effect

Unexplained reference numerals in Figure 1 will be described in the manufacturing method below.

According to the light emitting device, the manufacturing method of the light emitting device, the light emitting device package, and the lighting system according to the embodiment, the brightness and the operating voltage can be improved by controlling the Al composition or the In composition of the electron blocking layer.

Hereinafter, a method of manufacturing a light emitting device according to an embodiment will be described with reference to FIGS. 6 to 8.

First, the first substrate 105 is prepared as shown in FIG. 6. The first substrate 105 may include a conductive substrate or an insulating substrate. For example, the first substrate 105 may include sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, and Ga ₂ 0 ₃ May be used. An uneven structure may be formed on the first substrate 105, but is not limited thereto.

The first substrate 105 may be wet-cleaned to remove impurities on the surface.

A light emitting structure 110 including a first conductive semiconductor layer 112, an active layer 114, and a second conductive semiconductor layer 116 may be formed on the first substrate 105.

A buffer layer 107 may be formed on the first substrate 105. The buffer layer 107 may mitigate lattice mismatch between the material of the light emitting structure 110 and the first substrate 105. The material of the buffer layer 107 may be a Group III-V group compound semiconductor, eg, GaN, InN. It may be formed of at least one of, AlN, InGaN, AlGaN, InAlGaN, AlInN.

An undoped semiconductor layer may be formed on the buffer layer 107, but is not limited thereto.

The first conductivity type semiconductor layer 112 may be implemented as a group III-V compound semiconductor doped with a first conductivity type dopant, and when the first conductivity type semiconductor layer 112 is an N-type semiconductor layer, The first conductive dopant may be an N-type dopant and may include Si, Ge, Sn, Se, or Te, but is not limited thereto.

The first conductive semiconductor layer 112 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 + .

The first conductive semiconductor layer 112 may be formed of any one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP, InP.

The first conductive semiconductor layer 112 may form an N-type GaN layer using a chemical vapor deposition method (CVD), molecular beam epitaxy (MBE), or sputtering or hydroxide vapor phase epitaxy (HVPE). . In addition, the first conductive semiconductor layer 112 may include a silane containing n-type impurities such as trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and silicon (Si). The gas SiH ₄ may be injected and formed.

Next, the current diffusion layer 122 is formed on the first conductivity type semiconductor layer 112. The current diffusion layer 122 may be an undoped gallium nitride layer, but is not limited thereto. The current spreading layer 122 may have a thickness of 50 nm to 200 nm, but is not limited thereto.

Next, in an embodiment, the electron injection layer 124 may be formed on the current spreading layer 122. The electron injection layer 124 may be a first conductivity type gallium nitride layer. For example, the electron injection layer 124 can be efficiently injected by the n-type doping element is doped at a concentration of 6.0x10 ¹⁸ atoms / cm ³ ~ 8.0x10 ¹⁸ atoms / cm ³ . The electron injection layer 124 may be formed to a thickness of about 1000 μm or less, but is not limited thereto.

In addition, the embodiment may form a strain control layer (not shown) on the electron injection layer 124. For example, a strain control layer formed of In _y Al _x Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) / GaN may be formed on the electron injection layer 124.

The strain control layer can effectively alleviate the stress that is caused by the lattice mismatch between the first conductive semiconductor layer 112 and the active layer 114.

Further, as the strain control layer is repeatedly laminated in at least six cycles having compositions such as first In _x1 GaN and second In _x2 GaN, more electrons are collected at a low energy level of the active layer 114, The probability of recombination of holes is increased and the luminous efficiency can be improved.

Thereafter, an active layer 114 is formed on the strain control layer (not shown).

The active layer 114 has an energy band inherent in the active layer (light emitting layer) material because electrons injected through the first conductive semiconductor layer 112 and holes injected through the second conductive semiconductor layer 116 formed thereafter meet each other. It is a layer that emits light with energy determined by.

The active layer 114 may be formed of at least one of a single quantum well structure, a multi quantum well structure (MQW), a quantum-wire structure, or a quantum dot structure. For example, the active layer 114 may be formed with a multiple quantum well structure by injecting trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) But is not limited thereto.

The well layer / barrier layer of the active layer 114 is formed of one or more pair structures of InGaN / GaN, InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, GaAs (InGaAs) / AlGaAs, GaP (InGaP) / AlGaP. But it is not limited thereto. The well layer may be formed of a material having a lower band gap than the band gap of the barrier layer.

In an embodiment, the electron blocking layer 126 is formed on the active layer 114 to improve the luminous efficiency by acting as electron blocking and cladding of the active layer. For example, the electron blocking layer 126 may be formed of Al _x In _y Ga _(1-xy) N (0 ≦ _x ≦ 1,0 ≦ _y ≦ 1) based semiconductor, and may be formed of the active layer 114. It may have a higher energy band gap than the energy band gap, and may be formed to a thickness of about 100 kPa to about 600 kPa, but is not limited thereto.

In addition, the electron blocking layer 126 may be formed of a superlattice made of Al _z Ga _(1-z) N / GaN (0? _Z ? 1), but is not limited thereto.

The electron blocking layer 126 may efficiently block electrons overflowed by ion implantation into a p-type and increase hole injection efficiency. For example, the electron blocking layer 126 may efficiently block electrons that overflow due to ion implantation in a concentration range of about 10 ¹⁸ to 10 ²⁰ / cm ³ and increase the injection efficiency of holes.

In order to solve the above problems, the embodiment may control the composition during growth of the electron blocking layer to improve the droop phenomenon of efficiency and increase the light extraction efficiency.

In addition, the second electron blocking layer 126b has Al _{x 2} In _{y 2} Ga _(1- _x _2- _{y 2} ₎ N (where ₀ _{≦ x 2 ≦} ₁ and 0 ≦ y 2 ≤ 1), and the In content (y 2) is 0.01 < It may be y1 <0.2, and the content (x2) of Al in the second electron blocking layer 126b may be 0.1 <x2 <0.2, but is not limited thereto.

Accordingly, according to the embodiment, it can be seen that the internal quantum efficiency (IQE) is increased according to the increase in the applied voltage (V), compared to the prior art, and the embodiment can increase the QCSE reduction and light extraction effect.

Next, a second conductivity type semiconductor layer 116 is formed on the electron blocking layer 126.

The second conductive type semiconductor layer 116 is a second conductive type dopant is doped -5-group three-V compound semiconductor, for _{example, In x Al y Ga 1 -x-} y N (0≤x≤1, 0≤y And a semiconductor material having a composition formula of ≦ 1, 0 ≦ x + y ≦ 1). When the second conductive semiconductor layer 116 is a P-type semiconductor layer, the second conductive dopant may include Mg, Zn, Ca, Sr, Ba, or the like as a P-type dopant.

The second conductivity type semiconductor layer 116 is a bicetyl cyclone containing p-type impurities such as trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and magnesium (Mg) in the chamber. Pentadienyl magnesium (EtCp ₂ Mg) {Mg (C ₂ H ₅ C ₅ H ₄ ) ₂ } may be injected to form a p-type GaN layer, but is not limited thereto.

In an exemplary embodiment, the first conductive semiconductor layer 112 may be an N-type semiconductor layer, and the second conductive semiconductor layer 116 may be a P-type semiconductor layer, but is not limited thereto. In addition, a semiconductor, for example, an N-type semiconductor layer (not shown) having a polarity opposite to that of the second conductive type may be formed on the second conductive type semiconductor layer 116. Accordingly, the light emitting structure 110 may be implemented as any one of an N-P junction structure, a P-N junction structure, an N-P-N junction structure, and a P-N-P junction structure.

Next, the transparent electrode layer 130 is formed on the second conductive semiconductor layer 116. For example, the transparent electrode layer 130 may be formed by stacking multiple single metals, metal alloys, metal oxides, and the like to efficiently inject carriers. For example, the transparent electrode layer 130 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), or IGTO. (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO Nitride), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), ZnO, IrOx, RuOx, NiO, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt At least one of Au, Hf, and the like may be formed, and the material is not limited thereto.

Next, as shown in FIG. 7, the transparent electrode layer 130, the light emitting structure 110, and the like are partially removed to expose the first conductive semiconductor layer 112.

Next, as shown in FIG. 8, a first electrode 141 is formed on the exposed first conductive semiconductor layer 112, and a second electrode 142 is formed on the transparent electrode layer 130.

According to the light emitting device, the manufacturing method of the light emitting device, the light emitting device package, and the illumination system according to the embodiment, the brightness and the operating voltage can be improved by controlling the Al composition of the electron blocking layer.

9 is a view illustrating a light emitting device package in which a light emitting device is installed, according to embodiments.

The light emitting device package 200 according to the embodiment includes a package body 205, a third electrode layer 213 and a fourth electrode layer 214 provided on the package body 205, a package body 205, And a molding member 230 surrounding the light emitting device 100. The light emitting device 100 is electrically connected to the third electrode layer 213 and the fourth electrode layer 214,

The package body 205 may include a silicon material, a synthetic resin material, or a metal material, and an inclined surface may be formed around the light emitting device 100.

The third electrode layer 213 and the fourth electrode layer 214 are electrically isolated from each other and provide power to the light emitting device 100. The third electrode layer 213 and the fourth electrode layer 214 may function to increase light efficiency by reflecting the light generated from the light emitting device 100, And may serve to discharge heat to the outside.

The light emitting device 100 may be a horizontal type light emitting device illustrated in FIG. 1, but is not limited thereto.

The light emitting device 100 may be installed on the package body 205 or on the third electrode layer 213 or the fourth electrode layer 214.

The light emitting device 100 may be electrically connected to the third electrode layer 213 and / or the fourth electrode layer 214 by a wire, flip chip, or die bonding method. In the exemplary embodiment, the light emitting device 100 is electrically connected to the third electrode layer 213 and the fourth electrode layer 214 through a wire, but is not limited thereto.

The molding member 230 surrounds the light emitting device 100 to protect the light emitting device 100. In addition, the molding member 230 may include a phosphor 232 to change the wavelength of light emitted from the light emitting device 100.

A light guide plate, a prism sheet, a diffusion sheet, a fluorescent sheet, and the like, which are optical members, may be disposed on a path of light emitted from the light emitting device package. The light emitting device package, the substrate, and the optical member may function as a backlight unit or function as a lighting unit. For example, the lighting system may include a backlight unit, a lighting unit, a pointing device, a lamp, and a streetlight.

10 is a perspective view 1100 of a lighting unit according to an embodiment. However, the lighting unit 1100 of FIG. 10 is an example of a lighting system, but is not limited thereto.

In the embodiment, the lighting unit 1100 is connected to the case body 1110, the light emitting module unit 1130 installed on the case body 1110, and the case body 1110 and receive power from an external power source. It may include a terminal 1120.

The case body 1110 may be formed of a material having good heat dissipation characteristics. For example, the case body 1110 may be formed of a metal material or a resin material.

The light emitting module unit 1130 may include a substrate 1132 and at least one light emitting device package 200 mounted on the substrate 1132.

The substrate 1132 may be a circuit pattern printed on an insulator, and for example, a general printed circuit board (PCB), a metal core PCB, a flexible PCB, a ceramic PCB, and the like. It may include.

In addition, the substrate 1132 may be formed of a material that reflects light efficiently, or the surface may be formed of a color that reflects light efficiently, for example, white, silver, or the like.

The at least one light emitting device package 200 may be mounted on the substrate 1132. Each of the light emitting device packages 200 may include at least one light emitting diode (LED) 100. The light emitting diodes 100 may include colored light emitting diodes emitting red, green, blue, or white colored light, and UV light emitting diodes emitting ultraviolet (UV) light.

The light emitting module unit 1130 may be disposed to have a combination of various light emitting device packages 200 to obtain color and luminance. For example, a white light emitting diode, a red light emitting diode, and a green light emitting diode may be combined to secure high color rendering (CRI).

The connection terminal 1120 may be electrically connected to the light emitting module unit 1130 to supply power. In an embodiment, the connection terminal 1120 is coupled to the external power source by a socket, but is not limited thereto. For example, the connection terminal 1120 may be formed in a pin shape and inserted into an external power source, or may be connected to the external power source by a wire.

11 is an exploded perspective view 1200 of a backlight unit according to an embodiment. However, the backlight unit 1200 of FIG. 11 is an example of the illumination system, and the present invention is not limited thereto.

The backlight unit 1200 according to the embodiment includes a light guide plate 1210, a light emitting module unit 1240 that provides light to the light guide plate 1210, a reflective member 1220 under the light guide plate 1210, and the light guide plate. 1210, a bottom cover 1230 for accommodating the light emitting module unit 1240 and the reflective member 1220, but is not limited thereto.

The light guide plate 1210 serves to diffuse light into a surface light source. The light guide plate 1210 may be made of a transparent material such as acrylic resin such as PMMA (polymethyl methacrylate), polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin copolymer (COC), and polyethylene naphthalate Resin. &Lt; / RTI >

The light emitting module unit 1240 provides light to at least one side of the light guide plate 1210 and ultimately serves as a light source of a display device in which the backlight unit is installed.

The light emitting module 1240 may be in contact with the light guide plate 1210, but is not limited thereto. Specifically, the light emitting module 1240 includes a substrate 1242 and a plurality of light emitting device packages 200 mounted on the substrate 1242. The substrate 1242 is mounted on the light guide plate 1210, But is not limited to.

The substrate 1242 may be a printed circuit board (PCB) including a circuit pattern (not shown). However, the substrate 1242 may include not only a general PCB, but also a metal core PCB (MCPCB), a flexible PCB (FPCB), and the like.

The plurality of light emitting device packages 200 may be mounted on the substrate 1242 such that a light emitting surface on which the light is emitted is spaced apart from the light guiding plate 1210 by a predetermined distance.

The reflective member 1220 may be formed under the light guide plate 1210. The reflection member 1220 reflects the light incident on the lower surface of the light guide plate 1210 so as to face upward, thereby improving the brightness of the backlight unit. The reflective member 1220 may be formed of, for example, PET, PC, or PVC resin, but is not limited thereto.

The bottom cover 1230 may receive the light guide plate 1210, the light emitting module 1240, and the reflective member 1220. For this purpose, the bottom cover 1230 may be formed in a box shape having an opened upper surface, but the present invention is not limited thereto.

The bottom cover 1230 may be formed of a metal material or a resin material, and may be manufactured using a process such as press molding or extrusion molding.

According to the light emitting device, the manufacturing method of the light emitting device, the light emitting device package, and the lighting system according to the embodiment, the brightness and the operating voltage can be improved by controlling the composition of the electron blocking layer.

The features, structures, effects and the like described in the embodiments are included in at least one embodiment and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in each embodiment may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Accordingly, the contents of such combinations and modifications should be construed as being included in the scope of the embodiments.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. It can be seen that the modification and application of branches are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

100: light emitting element, 112: first conductivity type semiconductor layer
114a: quantum well 114a, 114b: quantum wall, 114: active layer
126: electron blocking layer, 126a: first electron blocking layer
126b: second electron blocking layer, 126c: third electron blocking layer
116: second conductivity type semiconductor layer

Claims

A first conductive semiconductor layer;
An active layer formed on the first conductivity type semiconductor layer including a quantum well and a quantum wall;
An electron blocking layer on the active layer; And
And a second conductivity type semiconductor layer on the electron blocking layer.
The electron blocking layer,
A first electron blocking layer having an energy band gap equal to or greater than an energy band gap of the quantum wall; And
And a second electron blocking layer on the first electron blocking layer, the energy band gap of which gradually decreases from the active layer toward the second conductive semiconductor layer.

The method according to claim 1,
And a third electron blocking layer having an energy band gap greater than or equal to that of the first electron blocking layer between the first electron blocking layer and the second electron blocking layer.

3. The method according to claim 1 or 2,
The maximum value of the energy bandgap of the second electron blocking layer is larger than the energy bandgap of the first electron blocking layer.

3. The method according to claim 1 or 2,
The first electron blocking layer includes Al _x1 In _y1 Ga _(1-x1- _y1 ₎ N (where 0 ≦ x1 ≦ ₁ and 0 ≦ _y1 ≦ 1).
The second electron blocking layer includes Al _x2 In _y2 Ga _(1-x2- _y2 ₎ N (where 0 ≦ _x2 ≦ 1 and 0 ≦ _y2 ≦ 1).
The composition (x2) of Al in the second electron blocking layer is gradually reduced in the direction of the second conductive semiconductor layer in the active layer.

3. The method according to claim 1 or 2,
The first electron blocking layer includes Al _x1 In _y1 Ga _(1-x1- _y1 ₎ N (where 0 ≦ x1 ≦ ₁ and 0 ≦ _y1 ≦ 1).
The second electron blocking layer includes Al _x2 In _y2 Ga _(1-x2- _y2 ₎ N (where 0 ≦ _x2 ≦ 1 and 0 ≦ _y2 ≦ 1).
The composition (y2) of In of the second electron blocking layer is gradually increased in the direction of the second conductive semiconductor layer in the active layer.

5. The method of claim 4,
The second electron blocking layer includes Al _x2 In _y2 Ga _(1-x2- _y2 ₎ N (where 0 ≦ _x2 ≦ 1 and 0 ≦ _y2 ≦ 1).
And a composition (x2) of Al of the second electron blocking layer is higher than an Al composition (x1) of the first electron blocking layer.

6. The method of claim 5,
The second electron blocking layer includes Al _x2 In _y2 Ga _(1-x2- _y2 ₎ N (where 0 ≦ _x2 ≦ 1 and 0 ≦ _y2 ≦ 1).
The light emitting device of In of the second electron blocking layer (y2) is lower than the In composition (y1) of the first electron blocking layer.