KR20130018069A

KR20130018069A - Light emitting device

Info

Publication number: KR20130018069A
Application number: KR1020110080908A
Authority: KR
Inventors: 정종필; 김종국; 황정현
Original assignee: 엘지이노텍 주식회사
Priority date: 2011-08-12
Filing date: 2011-08-12
Publication date: 2013-02-20

Abstract

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 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; And a second conductivity type semiconductor layer on the active layer, wherein the quantum well of the active layer is In _p Ga ₁ _- _p N quantum well (where 0 <p <1); And In _y Al _z Ga _(1-yz) N quantum wells (where 0 <y <1, 0 <z <1) and 0 <y + z <1).

Description

[0001] LIGHT EMITTING DEVICE [0002]

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

A light emitting device is a device that converts electrical energy into light energy, and various colors can be realized by adjusting the composition ratio of the compound semiconductor.

The light emitting device according to the prior art includes an N-type GaN layer and a P-type GaN layer and an active layer therebetween, and the quantum wells (MQW) constituting the active layer are InGaN quantum wells and GaN quantum barriers. ), And electrons injected into the active layer through the N-type GaN layer and holes injected into the active layer through the P-type GaN layer are bound to the InGaN quantum well and are coupled to each other to generate light.

The efficiency of the light emitting device can be maximized by improving the IQE (internal quantum efficiency) and EQE (external quantum efficiency).

According to the prior art, research is being conducted on the optimization of the multi-quantum well (MQW) and the hole injection efficiency to improve the internal quantum efficiency in the epitaxial growth of the light emitting device.

On the other hand, as the size of horizontal chips decreases, the reliability improvement and the internal quantum efficiency droop have been raised.

For example, GaN and InN, which are nitride semiconductor materials, have the same crystallographic orientation on hetero-bulk substrates, and when grown in a thin film form, their lattice constant difference is about 10%. For example, the plane lattice constant of InN is about 10% larger than the plane lattice constant of GaN.

Therefore, the quantum well formed by mixing GaN and InN in a ratio has an InGaN composition, and the lattice constant of the InGaN quantum well is larger than GaN constituting the quantum wall. Therefore, the InGaN quantum well is severely subjected to compressive stress in the active layer of the InGaN quantum well / GaN quantum wall structure formed on the N-type GaN substrate.

Severe compressive stresses acting on InGaN quantum wells generate a large internal field, creating a piezo electric field and modifying the energy band structure of the InGaN quantum wells.

As a result, electrons and holes in a conventional rectangular-potential quantum well are spatially separated to reduce recombination efficiency, resulting in a QCSE (quantum-confined Stark effect) phenomenon in which the self-luminous rate is significantly lowered. .

In addition, according to the related art, a droop phenomenon in which luminous efficiency decreases as the current increases, thereby causing a problem in that the luminous efficiency decreases as the current increases.

Embodiments provide a high efficiency light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system.

In addition, the embodiment is to provide a light emitting device, a method of manufacturing a light emitting device, a light emitting device package and an illumination system with improved reliability.

In addition, the embodiment is to provide a high output light emitting device, a method of manufacturing a light emitting device, a light emitting device package and an illumination system that can improve the droop phenomenon.

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; And a second conductivity type semiconductor layer on the active layer, wherein the quantum well of the active layer is In _p Ga ₁ _- _p N quantum well (where 0 <p <1); And In _y Al _z Ga _(1-yz) N quantum wells (where 0 <y <1, 0 <z <1) and 0 <y + z <1).

In addition, the light emitting device according to the embodiment includes a first conductivity type semiconductor layer; An active layer disposed on the first conductivity type semiconductor layer and having quantum wells and quantum walls repeatedly stacked; A last quantum wall disposed on the active layer and having an energy bandgap larger than the quantum wall and a thickness thicker than the quantum wall; And a second conductivity type semiconductor layer disposed on the last quantum wall, wherein the quantum well has a step with the first quantum well on the first quantum well and the first quantum well. And a second quantum well having a smaller energy bandgap and having a thickness thicker than that of the first quantum well.

According to the embodiment, it is possible to provide a light emitting device having high efficiency, a manufacturing method of the light emitting device, a light emitting device package and an illumination system.

In addition, the embodiment can provide a light emitting device, a manufacturing method of the light emitting device, a light emitting device package and an illumination system with improved reliability.

In addition, the embodiment can provide a high output light emitting device, a manufacturing method of the light emitting device, a light emitting device package, and an illumination system in which the droop phenomenon is improved.

1 is a cross-sectional view of a light emitting device according to an embodiment.
2 to 4 are cross-sectional views of the active layer in the light emitting device according to the embodiment.
5 and 6 are views illustrating internal quantum efficiency (IQE) results in the light emitting device according to the embodiment.
7 is an exemplary diagram illustrating a band diagram of a quantum well of a light emitting device according to an embodiment, and a comparative example of recombination efficiency of electrons and holes according to the related art and an embodiment.
8 is an IV curve of a light emitting device according to the prior art and 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, and FIGS. 2 to 4 are cross-sectional views of the active layer 114 in the light emitting device according to the embodiment.

The light emitting device 100 according to the embodiment includes a first conductive semiconductor layer 112, an active layer 114 and an active layer formed on the first conductive semiconductor layer 112, including a quantum well and a quantum wall. The second conductive semiconductor layer 116 is included on the 114.

The first conductivity type semiconductor layer 112, the active layer 114, and the second conductivity type semiconductor layer 116 may form a light emitting structure 110.

The light emitting device 100 according to the embodiment is disposed on the first conductive semiconductor layer 112 and the first conductive semiconductor layer 112, and the quantum well 114W and the quantum wall 114B are repeatedly stacked. The last quantum wall 114BL and the last quantum wall 114BL which are disposed on the active layer 114 and the active layer 114 and have an energy bandgap larger than the quantum wall 114B and a thickness thicker than the quantum wall. And a second conductivity type semiconductor layer 116 disposed thereon, wherein the quantum well 114W has a step with the first quantum well on the first quantum well and the first quantum well. An energy band gap smaller than that of the quantum well may include a second quantum well having a thickness greater than that of the first quantum well.

The light emitting structure 110 may be formed on a substrate 105, and the substrate 105 may include a conductive substrate or an insulating substrate. For example, the 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.

1 illustrates a horizontal light emitting device, but the embodiment is not limited thereto and may be applied to a vertical light emitting device. For example, the substrate 105 may be removed, and a pad electrode (not shown) may be formed under the exposed light emitting structure 110, and a second electrode layer (not shown) may be formed above the light emitting structure 110. Can be.

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 conductivity type dopant may be an N type dopant and may include Si, Ge, Sn, Se, 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 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. The active layer 114 will be described later in detail.

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 conductivity type semiconductor layer 116 is a P type semiconductor layer, the second conductivity type dopant may include Mg, Zn, Ca, Sr, Ba, or the like as a P type dopant.

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.

In addition, the embodiment is to provide a high output light emitting device, a method of manufacturing a light emitting device, a light emitting device package and an illumination system with improved droop phenomenon.

To this end, the embodiment can optimize the structure of the active layer to minimize the grid mismatch between the quantum well and the quantum wall to improve the reliability and improve the internal quantum efficiency.

2 is a cross-sectional view of the active layer 114A in the light emitting device according to the first embodiment.

In an exemplary embodiment, the quantum well 114W of the active layer 114 may be In _y Al _z Ga _(1-yz) N quantum well (where 0 <y <1, 0 <z <1, 0 <y + z <1). may include _p N quantum well (where, 0 <p <1) ( 114Wb) -) (114Wa) and said in _y Al _z Ga _(1-yz) N quantum well (in _p Ga ₁ on 114Wa) .

According to the first embodiment, the In _y Al _z Ga _(1-yz) N quantum well 114Wa is disposed on the In _x Ga ₁ _- _x N quantum wall 114B, and the In _p Ga ₁ _- _p N The quantum well 114Wb may be disposed on the In _y Al _z Ga _(1-yz) N quantum well 114Wa.

According to an embodiment In _p Ga ₁ _- _p N quantum well (114Wb) and In _y Al _z Ga _(1-yz) N quantum between In _x Ga ₁ _- _x N quantum wall (0 <x <1) (114B) Improves reliability and internal quantum efficiency (IQE) by minimizing misfit dislocation by forming two-step quantum wells of wells 114Wa to reduce the crystal lattice difference between quantum wells and quantum walls can do.

For example, according to the embodiment, In _y Al _z Ga _(1-yz) N quantum well 114W including Al is formed to grow a lattice matched well layer.

In an embodiment the composition of the In the _{In y Al z Ga (1-} yz) N quantum well (114Wa) (y) is a In _p Ga ₁ _- smaller than the composition of In (p) of the _p N quantum well (114Wb) Can be.

For example, the composition _{y of} the In _y Al _z Ga _(1-yz) N quantum well 114Wa is set in a range of about 10% to 20%, thereby reducing the crystal lattice difference between the quantum well and the quantum wall. By reducing the occurrence of misfit dislocation, the reliability and internal quantum efficiency (IQE) can be improved.

According to the embodiment _{In y Al z Ga (1-} yz) N quantum well (114Wa) Composition (y) a In _p Ga ₁ of In _- smaller than the composition (p) of the In of the _p N quantum well (114Wb) set Accordingly, reliability and internal quantum efficiency (IQE) can be improved by reducing the crystal lattice difference between the quantum walls contacting the In _y Al _z Ga _(1-yz) N quantum well 114Wa.

Example said _{In y Al z Ga (1-} yz) in N quantum well (114Wa) is a In _p Ga ₁ _- and also improve the reliability and the internal quantum efficiency (IQE) being formed to be thinner than the _p N quantum well (114Wb) At the same time, by not forming too thick, it is possible to prevent the performance degradation of the quantum well by Al. For example, the In _y Al _z Ga _(1-yz) N quantum well 114Wa may be formed to a thickness of about 4 kV to about 6 kW, and the In _p Ga ₁ _- _p N quantum well 114Wb may be about It may be formed to a thickness of 25Å to about 35Å, but is not limited thereto.

FIG. 5 is a diagram illustrating an internal quantum efficiency (IQE) result in the light emitting device according to the embodiment. In FIG. 5, the composition _{y of} In _y Al _z Ga _(1-yz) N quantum well 114W is about Illustrative examples and examples of the internal quantum efficiency (IQE) result of 15% are not limited to these compositions.

Referring to FIG. 5, a two-step quantum well of In _p Ga ₁ _- _p N quantum well 114 Wb and In _y Al _z Ga _(1-yz) N quantum well 114W is formed between quantum walls. It can be seen in (A1) that the internal quantum efficiency is increased compared to the prior art (B1), and the droop phenomenon in which the energy efficiency is reduced at high current density is improved.

2, the both walls of the active layer 114 in the examples are In _x Ga ₁ _- _x N may include a quantum wall (0 <x <1) ( 114B).

According to the embodiment, by providing a quantum wall including indium (In), the internal quantum efficiency (IQE) can be improved, and the droop phenomenon can be remarkably improved.

In an embodiment, the In _x Ga ₁ _- _x N quantum wall 114B may include indium (In) in a ratio of about 0.5% to about 10%, and as the indium is included in the quantum wall, the energy band gap is narrowed. The mobility of the carrier is very good, and the distribution of the light emitting region is expanded, and the crystallinity is improved by indium, thereby improving the piezo-electric field and improving the internal quantum efficiency (IQE) by 5% or more.

In an embodiment, the In _x Ga ₁ _- _x N quantum wall 114B is ineffective when the composition of indium (In) is less than 0.5%, and when the composition of the indium is greater than 10%, the barrier structure may collapse. Can be.

The In _x Ga ₁ _- _x N quantum wall (114B) in the last corresponding to the nearest i.e., the last quantum wall on the P-type semiconductor layer In _x Ga ₁ _- _x N quantum wall (114BL) is different from the In _x Ga ₁ _- _x N can be formed thicker than the quantum wall (114B).

The In _x Ga ₁ _- _x N quantum wall 114B may be formed to have a thickness of about 50 μs to about 55 μs, and the last In _x Ga ₁ _- _x N quantum wall 114BL may have a thickness of about 90 μs to about 100 μs. It may be formed, but is not limited thereto.

6 is a diagram illustrating an internal quantum efficiency (IQE) result in the light emitting device according to the embodiment. In FIG. 6, the In _x Ga ₁ _- _x N quantum wall 114B has an indium (In) composition of about 5%. Illustrative drawings and examples of the internal quantum efficiency (IQE) results are not limited to these compositions.

6 is in between the two walls In _p Ga ₁ _- in the case of forming a two-phase (two step) quantum well _p N quantum well (114Wb) and _{In y Al z Ga (1-} yz) N quantum well (114Wa) and This effect is obtained when In _x Ga ₁ _- _x N quantum walls 114B are used as quantum walls. According to the embodiment (A2), the internal quantum efficiency (IQE) is improved by 5% or more compared to the prior art (B2). It can be seen that the droop phenomenon is improved by more than 50%.

3 is a cross-sectional view of the active layer 114B in the light emitting device according to the second embodiment.

The second embodiment can employ the technical features of the first embodiment.

For example, according to the second embodiment, the In _y Al _z Ga _(1-yz) N quantum well 114W is disposed on the In _x Ga _1-x N quantum wall 114B, and the In _p Ga _{The 1} _- _p N quantum well 114Wb may be disposed on the In _y Al _z Ga _(1-yz) N quantum well 114Wa.

The second embodiment is the In _p Ga ₁ _- may further include the _{2 In y Al z Ga (1} -yz) N quantum well (114Wc) disposed on the _p N quantum well (114Wb).

According to the second embodiment, in the case where the active layer has a multi-quantum well structure, In _p Ga ₁ _- _p N quantum well 114 Wb is In _y Al _z Ga _(1-yz) N quantum well 114 Wa and the second In _y Al _z Intervening between Ga _(1-yz) N quantum wells 114Wc may further improve internal quantum efficiency and reliability.

4 is a cross-sectional view of the active layer 114C in the light emitting device according to the third embodiment.

The third embodiment can employ the technical features of the first embodiment.

For example, the quantum well (114W) of the active layer (114C) in the third embodiment In _p Ga ₁ _- _p N quantum well (where, 0 <p <1) ( 114Wb) and the In _p Ga ₁ _- _p The In _y Al _z Ga _(1-yz) N quantum well (0 <y <1, 0 <z <1) 114Wa may be included on the N quantum well 114Wb.

According to the third embodiment, the In _p Ga ₁ _- _p N quantum well 114Wb is disposed on the In _x Ga ₁ _- _x N quantum wall 114B and the In _y Al _z Ga _(1-yz) N quantum well (114Wa) is a in _p Ga ₁ _- may be disposed on the _p N quantum well (114Wb).

According to the third embodiment, the In _y Al _z Ga _(1-yz) N quantum well 114Wa is in contact with the In _x Ga _1-x N quantum wall 114B formed thereafter, thereby improving internal quantum efficiency and reliability. can do.

7 is an exemplary diagram illustrating a band diagram of a quantum well of a light emitting device according to an embodiment, and a comparative example of recombination efficiency of electrons and holes according to the prior art and the embodiment.

For example, FIG. 7A illustrates four light emitting devices having four quantum wells in a direction from a first conductive semiconductor layer 112 toward a second conductive semiconductor layer 116. Is a band diagram A3 of the quantum well in the embodiment. According to the embodiment, the stepped portion S may be formed in the energy band gap by including In _y Al _z Ga _(1-yz) N quantum well 114Wa.

According to the prior art, InGaN quantum wells are severely subjected to compressive stress in an active layer of an InGaN quantum well / GaN quantum wall structure formed on an N-type GaN substrate.

According to the light emitting device according to the embodiment, the lattice mismatch between the quantum well and the quantum wall can be minimized by optimizing the active layer quantum well and the quantum wall structure, thereby eliminating the piezo-electric field between the quantum well and the quantum wall. have.

Accordingly, in the embodiment, the band diagram A3 of the quantum well may recover a square-potential quantum well band diagram.

7 (b) is a comparative example of recombination efficiency (B4) of electrons and holes according to the related art and electron and hole recombination efficiency (A4) according to the embodiment.

In FIG. 7, the prior art is an example in which an InGaN quantum well / GaN quantum wall is provided as an active layer, and the active layer of the embodiment in FIG. 7 is In _x Ga ₁ _- _x N quantum wall 114B / In _y Al _z Ga _{(1). -yz)} N quantum well _{(114Wa) / in p Ga 1} - p N is not an example of the case having a quantum well (114Wb) or embodiment is not limited thereto.

According to the embodiment, the recombination efficiency (A4) of the electrons and holes may be increased by about 100% or more compared to the recombination efficiency (B4) of the prior art.

For example, as shown in FIG. 7B, the energy band level of the last well QW4 is restored, thereby significantly improving luminous efficiency and reliability in the last well, which is a main light emitting region.

8 is an exemplary view showing an I-V curve B5 of a light emitting device according to the related art and an I-V curve A5 of a light emitting device according to an embodiment.

In FIG. 8, the prior art is an example in which an InGaN quantum well / GaN quantum wall is provided as an active layer, and the active layer of the embodiment in FIG. 8 is In _x Ga ₁ _- _x N quantum wall 114B / In _y Al _z Ga _{(1). -yz)} N quantum well _{(114Wa) / in p Ga 1} - p N is not an example of the case having a quantum well (114Wb) or embodiment is not limited thereto.

It can be seen that the rated voltage VFa according to the embodiment is remarkably improved compared to the rated voltage VFb according to the prior art.

To this end, the embodiment forms a current diffusion layer 122, an electron injection layer (not shown), and a strain control layer 124 on the first conductivity type semiconductor layer 112, and then emits light by forming an active layer 114. It is possible to provide a light emitting device having high efficiency by improving the reliability of the device.

The current spreading 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.

Thereafter, an electron injection layer (not shown) may be formed on the current spreading layer 122. The electron injection layer (not shown) may be a first conductivity type gallium nitride layer. For example, the electron injection layer may be the electron injection efficiently by being doped at a concentration of the n-type doping element ^{6.0x10 18 atoms / cm 3 ~ 8.0x10} 18 atoms / cm 3.

In addition, the embodiment may form the strain control layer 124 on the electron injection layer. For example, the strain control layer 124 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.

The strain control layer 124 may effectively alleviate stresses that are odd due to lattice mismatch between the first conductivity-type semiconductor layer 112 and the active layer 114.

In addition, as the strain control layer 124 is repeatedly stacked in at least 6 cycles having a composition of 1 In _{x 1} GaN, 2 In _x 2 GaN, and the like, more electrons are collected at a lower energy level of the active layer 114, and as a result, As a result, the probability of recombination of electrons and holes may be increased, thereby improving luminous efficiency.

In addition, in the embodiment, an electron blocking layer 126 is formed between the active layer 114 and the second conductive semiconductor layer 116 to serve as electron blocking and cladding of the active layer. The luminous efficiency can be improved.

According to the embodiment, the electron blocking layer 126 is formed on the active layer 114 to serve as electron blocking and cladding of the active layer, thereby improving luminous efficiency. 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.

According to the embodiment, it is possible to provide a high efficiency light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system, including a current diffusion layer, an electron injection layer, a strain control layer, or an electron blocking layer.

An embodiment may include a first electrode 140 on the first conductive semiconductor layer 112 exposed by mesa etching and a second electrode 130 on the transparent electrode layer 129. The first electrode 140 and the second electrode 130 are titanium (Ti), chromium (Cr), nickel (Ni), aluminum (Al), platinum (Pt), gold (Au), tungsten (W), It may be formed of at least one of molybdenum (Mo), but is not limited thereto.

The transparent electrode layer 129 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), and indium gallium tin (IGTO). oxide), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IZO (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, Au, Hf It may be formed to include at least one of, and is not limited to these materials.

9 is a view illustrating a light emitting device package 200 in which a light emitting device is installed, according to embodiments.

The light emitting device package 200 according to the embodiment may include a package body 205, a third electrode layer 213 and a fourth electrode layer 214 installed on the package body 205, and the package body 205. The light emitting device 100 is installed at and electrically connected to the third electrode layer 213 and the fourth electrode layer 214, and a molding member 230 surrounding the light emitting device 100 is included.

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. A vertical light emitting device may also be applied.

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.

The molding member 230 may surround 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 the light emitted from the light emitting device 100.

A plurality of light emitting device packages according to the embodiment may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, a fluorescent sheet, or the like, which is an optical member, 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 surface light by diffusing light. The light guide plate 1210 is made of a transparent material, for example, an acrylic resin series such as polymethyl metaacrylate (PMMA), polyethylene terephthlate (PET), polycarbonate (PC), cycloolefin copolymer (COC), and polyethylene naphthalate (PEN). It may include one of the resins.

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 unit 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 light is emitted is spaced apart from the light guide 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 accommodate the light guide plate 1210, the light emitting module unit 1240, the reflective member 1220, and the like. 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.

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.

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; And
A second conductivity type semiconductor layer on the active layer;
The quantum well of the active layer,
In _p Ga ₁ _- _p N quantum well (where, 0 <p <1); And
A light emitting device comprising In _y Al _z Ga _(1-yz) N quantum wells (where 0 <y <1, 0 <z <1) and 0 <y + z <1).

The method according to claim 1,
The quantum wall of the active layer,
A light emitting device comprising In _x Ga ₁ _- _x N quantum walls (0 <x <1).

The method of claim 2,
The In _y Al _z Ga _(1-yz) N quantum well is disposed on the In _x Ga ₁ _- _x N quantum wall,
The In _p Ga ₁ _- _p N quantum well is disposed on the In _y Al _z Ga _(1-yz) N quantum well.

The method of claim 3,
A light emitting device further comprising a second In _y Al _z Ga _(1-yz) N quantum well disposed on the In _p Ga ₁ _- _p N quantum well.

The method of claim 2,
The In _p Ga ₁ _- _p N quantum well is disposed on the In _x Ga ₁ _- _x N quantum wall,
The In _y Al _z Ga _(1-yz) N quantum well is disposed on the In _p Ga ₁ _- _p N quantum well.

The method according to claim 1,
Said _{In y Al z Ga (1-} yz) N composition (y) of the In of the quantum well is a In _p Ga ₁ _- a small light emitting element than the composition (p) of _p N of the quantum well In.

The method of claim 6,
The composition (y) of In of the In _y Al _z Ga _(1-yz) N quantum well is in a range of 10% to 20%.

The method according to claim 1,
The In _y Al _z Ga _(1-yz) N quantum well
A light emitting device formed thinner than In _p Ga ₁ _- _p N quantum wells.

The method of claim 2,
The In _x (In) of the In _x Ga ₁ _- _x N quantum wall (x) is in the range of 0.5% to 10% light emitting device.

10. The method of claim 9,
The In _x Ga ₁ _- _x N quantum wall includes a last In _x Ga ₁ _- _x N quantum wall,
The Lat's In _x Ga ₁ _- _x N quantum wall is the In _x Ga ₁ _- _x N thick light-emitting device than the quantum wall.

A first conductive semiconductor layer;
An active layer disposed on the first conductivity type semiconductor layer and having quantum wells and quantum walls repeatedly stacked;
A last quantum wall disposed on the active layer and having an energy bandgap larger than the quantum wall and a thickness thicker than the quantum wall; And
A second conductivity type semiconductor layer disposed on the last quantum wall;
The quantum well is a second quantum having a smaller energy bandgap than the first quantum well and having a thickness thicker than the first quantum well so as to have a step with the first quantum well on the first quantum well and the first quantum well. Light emitting device comprising a well.