KR20130039353A - Light emitting device - Google Patents

Abstract

In one embodiment, a light emitting device includes: a first light emitting structure including a conductive substrate, a first semiconductor layer on the conductive substrate, a second semiconductor layer, and a first active layer formed between the first and second semiconductor layers; A second light emitting structure on the first light emitting structure, the second light emitting structure including a third semiconductor layer, a fourth semiconductor layer, and a second active layer formed between the third and fourth semiconductor layers; A first electrode electrically connected together, and a second electrode electrically connected with the fourth semiconductor layer, wherein the first semiconductor layer is electrically connected with the conductive substrate, and the first and third semiconductor layers are first conductive. Doped to a type, and the second and fourth semiconductor layers are doped to a second conductivity type.

Description

[0001] LIGHT EMITTING DEVICE [0002]

An embodiment relates to a light emitting element.

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.

Patent Document 10-2009-0082453 (hereinafter referred to as "1") in the light emitting device unit, the rectifier circuit unit for converting AC power into DC power, and the smoothing circuit unit for controlling the size of the rectified power supply to the light emitting device unit Disclosed is a light emitting device comprising a.

However, in the prior art 1, the rectifier circuit part and the smoothing circuit part are required to drive the light emitting element part from the AC power source, so that the economic efficiency of the light emitting device may be impaired.

The embodiment provides a light emitting device capable of driving both forward voltage and reverse voltage in an AC power supply.

In one embodiment, a light emitting device includes: a first light emitting structure including a conductive substrate, a first semiconductor layer on the conductive substrate, a second semiconductor layer, and a first active layer formed between the first and second semiconductor layers; A second light emitting structure on the first light emitting structure, the second light emitting structure including a third semiconductor layer, a fourth semiconductor layer, and a second active layer formed between the third and fourth semiconductor layers; A first electrode electrically connected together, and a second electrode electrically connected with the fourth semiconductor layer, wherein the first semiconductor layer is electrically connected with the conductive substrate, and the first and third semiconductor layers are first conductive. Doped to a type, and the second and fourth semiconductor layers are doped to a second conductivity type.

The light emitting device according to the embodiment can be driven at both the forward voltage and the reverse voltage in the AC power supply. Therefore, an AC power source can be used as a power source of the light emitting device without a separate rectifying circuit. Thus, there is no need for a separate electrical element, such as a rectifier circuit, or an ESD element in an AC power source.

In addition, in the light emitting device according to the embodiment, forward voltage driving and reverse voltage driving in an AC power source may be performed in one chip. Therefore, luminous efficiency per unit area can be improved.

In addition, since the light emitting device according to the embodiment includes a forward voltage driving light emitting structure and an reverse voltage driving light emitting structure in one chip in an AC power source and can be grown in one process, the light emitting device manufacturing process is simplified and the Economics can be improved.

1 is a cross-sectional view of a light emitting device according to an embodiment;
2 is a plan view of a light emitting device according to an embodiment;
3 is a circuit diagram of a light emitting device according to an embodiment;
4 is a driving diagram when a forward voltage is applied to the light emitting device according to the embodiment;
5 is a driving diagram when applying a reverse voltage of the light emitting device according to the embodiment;
6 is a cross-sectional view of a light emitting device according to the embodiment;
7 is a cross-sectional view of a light emitting device according to the embodiment;
8 is a partially enlarged cross-sectional view of a light emitting device according to the embodiment;
9 is a cross-sectional view of a light emitting device according to the embodiment;
10 is a cross-sectional view of a light emitting device according to the embodiment;
11 is a cross-sectional view of a light emitting device according to the embodiment;
12 is a cross-sectional view of a light emitting device according to the embodiment;
13 is a cross-sectional view of a light emitting device according to the embodiment;
14 is a cross-sectional view of a light emitting device according to the embodiment;
15 is a cross-sectional view of a light emitting device according to the embodiment;
16 is a cross-sectional view of a light emitting device according to the embodiment;
17 is a cross-sectional view of a light emitting device according to the embodiment;
18 is a cross-sectional view of a light emitting device according to the embodiment;
19 is a partially enlarged cross-sectional view of a light emitting device according to the embodiment;
20 is a view showing an energy band diagram of a light emitting device according to the embodiment;
21 is a view showing an energy band diagram of a light emitting device according to the embodiment;
22 is a cross-sectional view of a light emitting device according to the embodiment;
23 is a cross-sectional view of a light emitting device according to the embodiment;
24 is a conceptual diagram illustrating a circuit diagram of a lighting system including a light emitting device according to an embodiment;
25 is a conceptual diagram illustrating a circuit diagram of a lighting system including a light emitting device according to an embodiment;
26 is a perspective view of a light emitting device package including a light emitting device according to the embodiment;
27 is a cross-sectional view of a light emitting device package including a light emitting device according to the embodiment;
28 is a cross-sectional view of a light emitting device package including a light emitting device according to the embodiment;
29 is a perspective view of a lighting system including a light emitting device according to the embodiment;
30 is a cross-sectional view taken along the line CC ′ of the lighting system of FIG. 29;
31 is an exploded perspective view of a liquid crystal display device including a light emitting device according to the embodiment; and
32 is an exploded perspective view of a liquid crystal display including the light emitting device according to the embodiment.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

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

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

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

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

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

1 is a cross-sectional view of a light emitting device 100 according to the embodiment, and FIG. 2 is a plan view of the light emitting device 100 according to the embodiment.

1 and 2, the light emitting device 100 according to the embodiment includes a conductive substrate 142, a first semiconductor layer 122, a second semiconductor layer 126, and a conductive substrate 142. And a first light emitting structure 120 including a first active layer 124 formed between the first and second semiconductor layers 122 and 126, and a third semiconductor layer formed on the first light emitting structure 120. A second light emitting structure 130 including a second active layer 134 formed between the first and second semiconductor layers 132 and 132, and between the third and fourth semiconductor layers 132 and 136. A first electrode 144 connected with the third semiconductor layers 126 and 132, and a second electrode 146 connected with the fourth semiconductor layer 136, and the first semiconductor layer 122 is conductive. Electrically connected to the substrate 142, the first and third semiconductor layers 122, 132 are doped in a first conductivity type, and the second and fourth semiconductor layers 126, 136 are doped in a second conductivity type. Can be.

The conductive substrate 142 may be formed under the first semiconductor layer 122 and may be connected to the first semiconductor layer 122 to serve as one electrode. The conductive substrate 142 may include at least one of an ohmic layer (not shown), a reflective layer (not shown), and a bonding layer (not shown). For example, the conductive substrate 142 may be a structure of an ohmic layer / reflective layer / bonding layer, a stacked structure of an ohmic layer / reflective layer, or a structure of a reflective layer (including ohmic) / bonding layer, but is not limited thereto. For example, the conductive substrate 142 may have a form in which a reflective layer and an ohmic layer 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 first light emitting structure 120, the ohmic layer (not shown) may not be separately formed, but is not limited thereto.

The ohmic layer (not shown) is in ohmic contact with the bottom surface of the first light emitting structure 120, 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 a carrier into the first semiconductor layer 122 and is not necessarily formed.

In addition, the conductive substrate 142 may include a bonding layer (not shown), wherein the bonding layer (not shown) may be a barrier metal or a bonding metal such as Ti, Au, Sn, Ni, It may include, but is not limited to, at least one of Cr, Ga, In, Bi, Cu, Ag, or Ta.

Since the conductive substrate 142 is formed under the first semiconductor layer 122, it is necessary to separately etch the first and second light emitting structures 120 and 130 to form an electrode on the first semiconductor layer 122. There will be no.

In addition, since the conductive substrate 142 is formed over the lower area of the first semiconductor layer 122, current spreading and heat dissipation functions may be improved.

The first light emitting structure 120 may include a first semiconductor layer 122, a first active layer 124, and a second semiconductor layer 126.

The first semiconductor layer 122 may be located on the conductive substrate 142. The first semiconductor layer 122 may be doped with a first conductivity type. In this case, the first conductivity type may be n type. For example, the first semiconductor layer 122 may be implemented as an n-type semiconductor layer, and may provide electrons to the first active layer 124. The first semiconductor layer 122 may be a nitride based semiconductor layer. For example, semiconductor material having a compositional formula of the first semiconductor layer 122 is _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) It may include, for example, may include GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN. Meanwhile, the first semiconductor layer 122 may be a zinc oxide semiconductor layer. For example, the first semiconductor layer 122 may be formed of a semiconductor material having a composition formula of In _x Al _y Zn _{1 -x- y} O (0≤x≤1, 0≤y≤1, 0≤x + y≤≤). And include, for example, ZnO, AlO, AlZnO, InZnO, InO, InAlZnO. AlInO, and the like, but are not limited thereto. In addition, the first semiconductor layer 122 may be doped with n-type dopants such as Si, Ge, Sn, and the like.

In addition, an undoped semiconductor layer (not shown) may be further included below the first semiconductor layer 122, but embodiments are not limited thereto. The undoped semiconductor layer (not shown) is a layer formed to improve the crystallinity of the first semiconductor layer 122, except that the n-type dopant is not doped and thus has lower electrical conductivity than that of the first semiconductor layer 122. And may be the same as the first semiconductor layer 122.

The first active layer 124 may be formed on the first semiconductor layer 122. The first active layer 124 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 a group III-V group element. .

When the first active layer 124 has a quantum well structure, the first active layer 124 may have a multi-quantum well structure. In addition, the first active layer 124 may be a nitride-based or zinc oxide-based semiconductor layer. For example, the first active layer 124 is _{In x Al y Ga 1 -x- y} N well layer having a composition formula of (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1) and In _a It may have a single or multiple quantum well structure having a barrier layer having a composition formula of Al _b Ga _{1 -a- b} N (0 _{≦ a ≦ 1} , 0 _{≦ b ≦ 1} , 0 ≦ a + b ≦ 1). On the other hand, the well layer has a composition formula of In _x Al _y Zn _{1 -x- y} O (0≤x≤1, 0≤y≤1, 0≤x + y≤1), and the barrier layer is In _a Al _b Zn _1-ab O (0 ≦ a ≦ ₁ , 0 ≦ b ≦ 1, 0 ≦ a + b ≦ 1), but is not limited thereto. Meanwhile, the well layer may be formed of a material having a band gap smaller than the band gap of the barrier layer.

In addition, when the first active layer 124 has a multi-quantum well structure, each well layer (not shown), the barrier layer (not shown) may have different compositions, different thicknesses, and different band gaps, This will be described later.

A conductive clad layer (not shown) may be formed on or under the first active layer 124. The conductive cladding layer (not shown) may be formed of, for example, an AlGaN-based or AlZnO-based semiconductor, and may have a band gap larger than that of the first active layer 124.

The second semiconductor layer 126 may be doped with a second conductivity type. In this case, the second conductivity type may be p-type. For example, the second semiconductor layer 126 may be implemented as a p-type semiconductor layer to inject holes into the first active layer 124. The second semiconductor layer 126 may be a nitride based semiconductor layer. For example, semiconductor material having a composition formula of the second semiconductor layer 126 is _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) It may include, for example, may include GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN. Meanwhile, the second semiconductor layer 126 may be a zinc oxide semiconductor layer. For example, the second semiconductor layer 126 may include a semiconductor material having a composition formula of In _x Al _y Zn _{1 -x- y} O (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1). And ZnO, AlO, AlZnO, InZnO, InO, InAlZnO. AlInO, and the like, but is not limited thereto. The second semiconductor layer 126 may be doped with p-type dopants such as Mg, Zn, Ca, Sr, and Ba.

The first semiconductor layer 122, the first active layer 124, and the second semiconductor layer 126 may be, for example, metal organic chemical vapor deposition (MOCVD) or chemical vapor deposition (CVD). Vapor Deposition, Plasma-Enhanced Chemical Vapor Deposition (PECVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), Sputtering, etc. It may be formed using, but is not limited thereto.

In addition, the doping concentrations of the conductive dopants in the first semiconductor layer 122 and the second semiconductor layer 126 may be uniformly or non-uniformly formed. That is, the plurality of semiconductor layers may be formed to have various doping concentration distributions, but the invention is not limited thereto.

In addition, the first semiconductor layer 122 may be implemented as a p-type semiconductor layer, the second semiconductor layer 126 may be implemented as an n-type semiconductor layer, and the n-type or p-type semiconductor is formed on the second semiconductor layer 126. A semiconductor layer (not shown) including a layer may be formed. Accordingly, the first light emitting structure 120 may have at least one of np, pn, npn, and pnp junction structures.

The second light emitting structure 130 may be formed on the first light emitting structure 120.

The second light emitting structure 130 may include a third semiconductor layer 132, a second active layer 134, and a fourth semiconductor layer 136.

The third semiconductor layer 132 may be positioned on the second semiconductor layer 126. The third semiconductor layer 132 may be doped with the first conductivity type. In this case, the first conductivity type may be n type. For example, the third semiconductor layer 132 may be implemented as an n-type semiconductor layer, and may provide electrons to the second active layer 134. The third semiconductor layer 132 may be a nitride based semiconductor layer. For example, the third semiconductor layer 132 may include 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) For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, and the like may be included. Meanwhile, the first semiconductor layer 122 may be a zinc oxide semiconductor layer. For example, the third semiconductor layer 132 is a semiconductor material having a composition formula of In _x Al _y Zn _{1 -x- y} O (0≤x≤1, 0≤y≤1, 0≤x + y≤1). , For example ZnO, AlO, AlZnO, InZnO, InO, InAlZnO. The first semiconductor layer 122 may be doped with an n-type dopant, such as Si, Ge, Sn, or the like.

The second active layer 134 may be formed on the third semiconductor layer 132. The second active layer 134 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 a group III-V group element. .

The second active layer 134 may be formed in a quantum well structure. In addition, the second active layer 134 may be a nitride-based or zinc oxide-based semiconductor layer. For example, the second active layer 134 may include a well layer having a composition formula of In _x Al _y Ga _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1) and In _a Al _b It may have a single or multiple quantum well structure having a barrier layer having a composition formula of Ga _{1-a- b} N (0 _{≦ a ≦ 1} , 0 _{≦ b ≦ 1} , 0 ≦ a + b ≦ 1). On the other hand, the well layer has a composition formula of In _x Al _y Zn _{1 -x- y} O (0≤x≤1, 0≤y≤1, 0≤x + y≤1), and the barrier layer is In _a Al _b Zn _{1-a- b} O ( _{0≤a≤1, 0≤b≤1, 0≤a} + b≤1) may be formed to have a composition formula, but is not limited thereto. Meanwhile, the well layer may be formed of a material having a band gap smaller than the band gap of the barrier layer.

In addition, when the second active layer 134 has a multi-quantum well structure, each well layer (not shown) may have a different composition and a different band gap, which will be described later.

A conductive clad layer (not shown) may be formed on or under the second active layer 134. The conductive cladding layer (not shown) may be formed of, for example, an AlGaN-based or AlZnO-based semiconductor, and may have a band gap larger than that of the second active layer 134.

The fourth semiconductor layer 136 may be doped with a second conductivity type. In this case, the second conductivity type may be p-type. For example, the fourth semiconductor layer 136 may be implemented as a p-type semiconductor layer to inject holes into the second active layer 134. The fourth semiconductor layer 136 may be a nitride based semiconductor layer. For example, the fourth semiconductor material having a composition formula of the semiconductor layer 136 is _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) It may include, for example, may include GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN. Meanwhile, the fourth semiconductor layer 136 may be a zinc oxide semiconductor layer. For example, the fourth semiconductor layer 136 is a semiconductor material having a composition formula of In _x Al _y Zn _{1 -x- y} O (0≤x≤1, 0≤y≤1, 0≤x + y≤1). It may include, for example ZnO, AlO, AlZnO, InZnO, InO, InAlZnO. AlInO, and the like, but is not limited thereto. Meanwhile, the fourth semiconductor layer 136 may be doped with p-type dopants such as Mg, Zn, Ca, Sr, and Ba.

For example, the third semiconductor layer 132, the second active layer 134, and the fourth semiconductor layer 136 may be formed of, for example, metal organic chemical vapor deposition (MOCVD) or chemical vapor deposition (CVD). Vapor Deposition, Plasma-Enhanced Chemical Vapor Deposition (PECVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), Sputtering, etc. It may be formed using, but is not limited thereto.

In addition, the doping concentrations of the conductive dopants in the third semiconductor layer 132 and the fourth semiconductor layer 136 may be uniformly or non-uniformly formed. That is, the plurality of semiconductor layers may be formed to have various doping concentration distributions, but the invention is not limited thereto.

In addition, the third semiconductor layer 132 may be implemented as a p-type semiconductor layer, the fourth semiconductor layer 136 may be implemented as an n-type semiconductor layer, and the n-type or p-type semiconductor is formed on the fourth semiconductor layer 136. A semiconductor layer (not shown) including a layer may be formed. Accordingly, the second light emitting structure 130 may have at least one of np, pn, npn, and pnp junction structures.

The first light emitting structure 120 and the second light emitting structure 130 may be integrally formed. For example, the first light emitting structure 120 and the second light emitting structure 130 may be sequentially grown, but the present invention is not limited thereto. The second light emitting structure 130 may be formed of the same material, but is not limited thereto. In addition, as described above, the first and second light emitting structures 120 and 130 may have at least one of np, pn, npn, and pnp junction structures, respectively, and thus, the light emitting device 100 may include npnp, nppn, It may have at least one of npnpn, nppnp, pnnp, pnpn, pnnpn, pnpnp, npnnp, npnpn, npnnpn, npnpnp, pnpnp, pnppn, pnpnpn, and pnppnp junction structures, but is not limited thereto.

Meanwhile, the light generated by the first light emitting structure 120 and the second light emitting structure 130 may have different wavelengths, and the amount of light generated may also be different from each other. For example, the amount of light generated by the first light emitting structure 120 may be greater than the amount of light generated by the second light emitting structure 130.

In addition, the first light emitting structure 120 and the second light emitting structure 130 may have different structures, materials, thicknesses, compositions, and sizes, but are not limited thereto.

1 and 2, the light emitting device 100 is illustrated as including a first light emitting structure 120 and a second light emitting structure 130 formed on the first light emitting structure 120, but is not limited thereto. No, the light emitting device 100 may include at least two light emitting structures (not shown).

The first electrode 144 may be formed on at least one region of the second semiconductor layer 126 and the third semiconductor layer 132. For example, at least one region of the second light emitting structure 130 may be removed to expose one region of the second semiconductor layer 126 and the third semiconductor layer 132, and the first electrode 144 may be exposed to the exposed region. ) May be formed. That is, as shown in FIG. 1, the second and third semiconductor layers 126 and 132 include an upper surface facing the fourth semiconductor layer 136 and a lower surface facing the conductive substrate 142, and the upper surface has at least one region. Including the exposed area, the first electrode 144 may be disposed on the exposed area of the upper surface. Meanwhile, a hole penetrating a region of the third semiconductor layer 132 may be formed to expose a portion of the second semiconductor layer 126. The first electrode 144 may be connected to the second semiconductor layer 126 through the third semiconductor layer 132 through the hole.

Meanwhile, a method of exposing a part of the second and third semiconductor layers 126 and 132 to each other 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, the etching method may be a mesa etching method.

The second electrode 146 may be formed on the fourth semiconductor layer 136. The second electrode 146 may be formed in at least one region on the fourth semiconductor layer 136, and may be formed in the center or corner region of the fourth semiconductor layer 136, but is not limited thereto.

As the first electrode 144 is formed on the second and third semiconductor layers 126 and 132 and the second electrode 146 is formed on the fourth semiconductor layer 136, the first and second electrodes ( 144 and 146 may be formed in the same direction.

The conductive substrate 142 and the second electrode 146 may be interconnected. Accordingly, power having the same polarity may be applied to the first semiconductor layer 122 and the fourth semiconductor layer 136 through the conductive substrate 142 and the second electrode 146.

In addition, the first electrode 144 is formed on the second semiconductor layer 126 and the third semiconductor layer 132 to supply power having the same polarity to the second semiconductor layer 126 and the third semiconductor layer 132. Can be authorized.

Meanwhile, the first and second electrodes 144 and 146 may be conductive materials such as In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, It may include a metal selected from W, Ti, Ag, Cr, Mo, Nb, Al, Ni, Cu, and WTi, or may include an alloy thereof, and the metal material and IZO, IZTO, IAZO, IGZO , IGTO, AZO, ATO, and the like may include a transparent conductive material, but is not limited thereto.

In addition, at least one of the first and second electrodes 144 and 146 may have a single layer or a multilayer structure, but is not limited thereto.

Hereinafter, an operation of the light emitting device 100 according to the embodiment will be described with reference to FIGS. 3 to 5. In the following description, it is assumed that the first and third semiconductor layers 122 and 132 are n-type semiconductor layers, and the second and fourth semiconductor layers 126 and 136 are p-type semiconductor layers.

3 is a circuit diagram of a light emitting device 100 according to an embodiment.

As described above, the conductive substrate 142 is connected to the first semiconductor layer 122, the first electrode 144 is connected to the second semiconductor layer 126, and the third semiconductor layer 132, and the second electrode 146 may be connected to the fourth semiconductor layer 136, and the conductive substrate 142 and the second electrode 146 may be connected to each other. In this case, the first and third semiconductor layers 122 and 132 may be doped with the first conductivity type, and the second and fourth semiconductor layers 126 and 136 may be doped with the second conductivity type. Therefore, the light emitting device 100 according to the embodiment may have a circuit structure in which two light emitting diodes are connected in an anti-parallel structure as shown in FIG. 3.

4 is a view illustrating driving of the light emitting device 100 according to the embodiment when a forward bias is applied.

As shown in FIG. 4, in an AC power source, a positive voltage (+) may be connected to the first electrode 144, and a negative voltage (−) may be connected to the conductive substrate and the second electrodes 142 and 146. have.

In this case, a first current path A flowing from the second semiconductor layer 126 through the active layer 124 to the first semiconductor layer 124 is formed in the first light emitting structure 120. As described above, since the second semiconductor layer 126 is a p-type semiconductor layer and the first semiconductor layer 122 is formed of an n-type semiconductor layer, the first light emitting structure 120 is turned on so that the first active layer 124 is formed. ) Can generate light.

On the other hand, a positive voltage (+) is connected to the third semiconductor layer 132 and a negative voltage (-) is connected to the fourth semiconductor layer 136, and a reverse voltage is applied to the second light emitting structure 130. Thus, no current path is formed and the second light emitting structure 130 is turned off.

5 is a view illustrating driving of the light emitting device 100 when a reverse bias is applied to the light emitting device 100 according to the embodiment.

As illustrated in FIG. 5, a negative voltage (−) may be supplied to the first electrode 144, and a positive voltage (+) may be supplied to the conductive substrate and the third electrodes 142 and 146.

In this case, a second current path B flowing from the fourth semiconductor layer 136 through the second active layer 134 to the third semiconductor layer 134 is formed in the second light emitting structure 130. As described above, since the fourth semiconductor layer 136 is a p-type semiconductor layer, and the third semiconductor layer 132 is formed of an n-type semiconductor layer, the second light emitting structure 130 is turned on to form the second active layer 134. Can generate light.

Meanwhile, in the first light emitting structure 120, a positive voltage (+) is connected to the first semiconductor layer 122 and a negative voltage (−) is connected to the second semiconductor layer 126, thereby applying a reverse voltage. Thus, no current path is formed and the first light emitting structure 120 is turned off.

As shown in FIG. 4 and FIG. 5, the light emitting device 100 according to the embodiment may emit light for both forward bias and reverse bias in an AC power source.

Therefore, when the AC power source is used as the power source of the light emitting device 100, a separate rectifying circuit or a plurality of light emitting devices is not required. Therefore, the light emitting device 100 according to the embodiment and the light emitting device 100 according to the embodiment are The economics of the apparatus used can be improved.

In addition, since the light emitting device 100 formed of a single chip can emit light with respect to both the constant voltage bias and the reverse voltage bias, the light emission efficiency per unit area of the light emitting device 100 can be improved.

In addition, since a current path is formed for both the constant voltage and the reverse voltage, damage to the light emitting device 100 by ESD may be prevented, and a separate ESD protection device may not be required. In addition, since a separate ESD device may not be provided in the light emitting device package or the lighting device using the light emitting device 100 according to the embodiment, the volume of the light emitting device package or the lighting device may be reduced and the light of the ESD device may be reduced. Losses can be prevented.

In addition, each light emitting structure 120 and 130 generating light with respect to the reverse bias and the forward bias is included in one light emitting device 100 and each light emitting structure 120 and 13 is integrally formed so that one process In the first and second light emitting structures 120 and 130 may be grown. Therefore, the economics of the manufacturing process of the light emitting device 100 can be improved.

6 is a cross-sectional view of a light emitting device 100 according to the embodiment.

Referring to FIG. 6, the light emitting device 100 according to the embodiment may be formed on the support member 110, the conductive substrate 142 formed on the support member 110, and the conductive substrate 142. A first light emitting structure 120 including a first semiconductor layer 122, a second semiconductor layer 126, and a first active layer 124 formed between the first and second semiconductor layers 122 and 126; The second active layer 134 formed on the first light emitting structure 120 and formed between the third semiconductor layer 132, the fourth semiconductor layer 136, and the third and fourth semiconductor layers 132 and 136. It may include a second light emitting structure 130 including a.

The support member 110 may be formed using a material having excellent thermal conductivity and may be formed of a conductive material, and may be formed using a metal material or a conductive ceramic. The support member 110 may be formed in a single layer, or may be formed in a double structure or multiple structures.

That is, the support member 110 may be formed of any one selected from a metal, for example, Au, Ni, W, Mo, Cu, Al, Ta, Ag, Pt, and Cr, or may be formed of two or more alloys. The above materials can be laminated and formed. In addition, the support member 110 is Si, Ge, GaAs, ZnO, SiC, SiGe, GaN, Ga ₂ O ₃ It may be implemented as a carrier wafer such as.

The support member 110 may facilitate the emission of heat generated from the light emitting device 100 to improve the thermal stability of the light emitting device 100.

7 is a cross-sectional view of a light emitting device 100 according to the embodiment.

Referring to FIG. 7, the light emitting device 100 according to the embodiment is formed between the first semiconductor layer 122, the second semiconductor layer 126, and the first and second semiconductor layers 122 and 126. The first light emitting structure 120 including the first active layer 124, the third semiconductor layer 132, the fourth semiconductor layer 136, and the third and the third light emitting structures formed on the first light emitting structure 120. A second light emitting structure 130 including a second active layer 134 formed between the four semiconductor layers 132 and 136, and an intermediate layer formed between the first light emitting structure 120 and the second light emitting structure 130 ( 150).

The intermediate layer 150 may have a predetermined thickness to isolate the first light emitting structure 120 from the second light emitting structure 130. Meanwhile, as illustrated in FIG. 7, one region of the intermediate layer 150 may be removed, and the first electrode 144 may be formed to contact the second semiconductor layer 126 through the region.

The intermediate layer 150 may be, for example, an undoped semiconductor layer that is not doped. Therefore, the intermediate layer 150 may have low electrical conductivity because the p-type dopant or the n-type dopant is not doped. On the other hand, except that the dopant is not doped as described above may have the same composition and structure as each semiconductor layer forming the first light emitting structure 120, or the second light emitting structure 130.

As the intermediate layer 150 is formed between the first light emitting structure 120 and the second light emitting structure 130, diffusion between the first light emitting structure 120 and the second light emitting structure 130 occurs and leakage current is generated. This can be prevented.

Meanwhile, referring to FIG. 8, the intermediate layer 150 may have a multilayer structure including several layers 151, 152, 153, 154, and 155. Although several layers 151, 152, 153, 154, and 155 are illustrated in FIG. 10, the present invention is not limited thereto, and at least two layers may be formed.

Each layer 151, 152, 153, 154, 155 may have at least two different bandgaps. For example, the intermediate layer 150 may have a structure in which several layers 151, 152, 153, 154, and 155 having different band gaps are repeatedly stacked alternately, but is not limited thereto.

A growth substrate (not shown) in which the semiconductor layer is grown and the first semiconductor layer 122 may have a large difference in lattice constant. In particular, such crystal defects tend to increase with the growth direction. The intermediate layer 150 includes several layers 151, 152, 153, 154, and 155 having different bandgaps from each other, and is formed between the first light emitting structure 120 and the second light emitting structure 130, thereby forming an intermediate layer. (150) It can block the propagation of crystal defects occurring at the bottom. Therefore, it is possible to suppress the crystal defects from being transferred above the intermediate layer 150. Therefore, the reliability and luminous efficiency of the light emitting device 100 can be improved.

Meanwhile, the intermediate layer 150 may be formed of, for example, GaN, InN, InGaN, AlGaN, ZnO, AlO, AlZnO, InZnO, InO, InAlZnO. A semiconductor layer including AlInO may be included, and each layer may be disposed such that the layer having the smallest bandgap and the layer having the smallest bandgap are in contact with each other.

For example, the higher the composition of AlN, the larger the bandgap, and the higher the composition of InN, the smaller the bandgap, so that the bandgap of the layer containing InN is the lowest and the bandgap of the layer containing AlN can be the largest. have. Therefore, the layer containing AlN having the largest band gap and the layer containing InN having the smallest band gap can be formed in contact with each other.

On the other hand, the layer containing AlN having a small lattice constant generates tensile stress, and the layer containing InN having a large lattice constant may generate compressive stress. Therefore, when layers including AlN and layers including InN are alternately stacked, stress between layers can be alleviated.

The intermediate layer 150 may include a reflective material having a reflectance. Meanwhile, each of the layers 151, 152, 153, 154, and 155 may have at least two different refractive indices. The intermediate layer 150 may include several layers 151, 152, 153, 154, and 155 having at least two different refractive indices, such that the intermediate layer 150 may function as a distributed Bragg reflector (DBR) layer having reflectance.

Since the intermediate layer 150 has a reflectance, light generated in the first and second light emitting structures 120 and 130 may be reflected by the intermediate layer 150. Therefore, the light generated by the first light emitting structure 120 may be reflected without traveling through the second light emitting structure 130 to travel laterally. Meanwhile, the light generated by the second light emitting structure 130 may be reflected without traveling through the first light emitting structure 120 and may proceed upward. Therefore, light loss of the light emitting device 100 is reduced, and lateral light emission can be enabled.

9 and 10 are cross-sectional views showing a light emitting device 100 according to the embodiment.

9, the light emitting device 100 according to the embodiment is formed between the first semiconductor layer 122, the second semiconductor layer 126, and the first and second semiconductor layers 122 and 126. The first light emitting structure 120 including the first active layer 124, the third semiconductor layer 132, the fourth semiconductor layer 136, and the third and the third light emitting structures formed on the first light emitting structure 120. And a second light emitting structure 130 including a second active layer 134 formed between the four semiconductor layers 132 and 136, and at least one region of the side surfaces of the first and second light emitting structures 120 and 130. The first uneven portion 160 may be formed.

The first uneven portion 160 may be formed in at least one region of the side surfaces of the first and second light emitting structures 120 and 130, and may be formed in several regions or the entire region, but is not limited thereto. The first uneven portion 160 may be formed by performing etching on at least one region of the side surfaces of the first and second light emitting structures 120 and 130, but is not limited thereto.

Meanwhile, the etching process may include a wet and / or dry etching process, but is not limited thereto.

The etching process may be formed through a wet etching process using an etchant such as photo electrochemical (PEC) or KOH solution.

As the etching process is performed, first uneven parts 160 may be formed on side surfaces of the first and second light emitting structures 120 and 130, and the height may be 0.1 μm to 3 μm. The first uneven portion 160 may be irregularly formed in a random size or may have a desired shape and arrangement, but is not limited thereto. The first uneven portion 160 is an uneven surface and may include at least one of a texture pattern, an uneven pattern, and an uneven pattern.

In addition, the shape of the first concave-convex portion 160 may be formed to have various shapes such as a cylinder, a polygonal pillar, a cone, a polygonal pyramid, a truncated cone, a polygonal truncated cone, and preferably includes a horn shape.

The first uneven portion 160 prevents light generated from the first and second active layers 124 and 134 from totally reflecting from the side surfaces of the first and second light emitting structures 120 and 130 to be reabsorbed or scattered. The light extraction structure is formed. That is, the first uneven portion 160 has an incident angle of less than or equal to a critical angle when light generated from the first and second active layers 124 and 134 is incident on the side surfaces of the first and second light emitting structures 120 and 130. Can be formed.

As the first uneven portion 160 is formed on the side surfaces of the first and second light emitting structures 120 and 130, light generated from the first and second active layers 124 and 134 is first and second. Since it is possible to prevent the total reflection from the side of the light emitting structure (120, 130) to be reabsorbed or scattered, it can contribute to the improvement of light extraction efficiency of the light emitting device (100).

Meanwhile, as illustrated in FIG. 10, side surfaces of the first and second light emitting structures 120 and 130 may be formed to have an inclination angle. As the side surfaces of the first and second light emitting structures 120 and 130 are formed to have an inclination angle, an etching process is performed on the side surfaces of the first and second light emitting structures 120 and 130 to form a twenty-first uneven portion ( 160 may be easy to form. In addition, the light distribution pattern of the light emitting device 100 may be improved by the light traveling through the side surfaces of the first and second light emitting structures 120 and 130 in various directions including the lateral direction.

On the other hand, when the inclination angle is too large or too small, the ratio of the size of the first and second active layers 124 and 134 to the size of the light emitting device 100 is reduced, so that the luminous efficiency of the light emitting device 100 is reduced. The angle of inclination may be between 50 ° and 90 °.

Meanwhile, the growth surfaces of the first and second light emitting structures 120 and 130 may be nonpolar or semipolar crystal surfaces. For example, the C-plane {0001} of the GaN crystals forming the first and second light emitting structures 120 and 130 may be formed on the sides of the first and second light emitting structures 120 and 130, and thus Ga-face, or N-face, may be formed on the side surfaces of the first and second light emitting structures 120 and 130.

That is, when the growth surfaces of the first and second light emitting structures 120 and 130 are nonpolar or semipolar crystal surfaces, the Ga-face or N-face may be formed on the side surfaces of the first and second light emitting structures 120 and 130. Can be formed. Since the Ga-face and the N-face may be easily etched through a wet etching process, the uneven portions 160 may be formed on the side surfaces of the first and second light emitting structures 120 and 130 through the wet etching process. have. In addition, since the growth surfaces of the first and second light emitting structures 120 and 130 are formed as non-polar or semi-polar crystal surfaces, the piezoelectric polarization and the electrostatic field due to the piezoelectric polarization are weakened. The probability of recombination of electrons and holes in the second active layers 132 and 134 is increased, and the luminous efficiency of the light emitting device 100 can be improved.

11 is a cross-sectional view of a light emitting device according to the embodiment.

Referring to FIG. 11, the light emitting device 100 according to the embodiment may include a conductive substrate 142, a first semiconductor layer 122, a second semiconductor layer 126, and a first semiconductor layer on the conductive substrate 142. And a first light emitting structure 120 including a first active layer 124 formed between the second semiconductor layers 122 and 126, and a third semiconductor layer 132 formed on the first light emitting structure 120. And a second light emitting structure 130 including a fourth semiconductor layer 136 and a second active layer 134 formed between the third and fourth semiconductor layers 132 and 136, and the conductive substrate 142. ) And the second electrode 146 are connected, a first insulating layer 148 is formed between the second electrode 146 and the first and second light emitting structures 120 and 130, and the first electrode 144 The second insulating layer 149 may be formed between the second light emitting structure 130 and the second light emitting structure 130.

The conductive substrate 142 and the second electrode 146 may be formed to be connected to each other, for example, may be formed continuously.

Meanwhile, a connection electrode 147 having electrical conductivity may be formed between the conductive substrate 142 and the second electrode 146 to connect the conductive substrate 142 and the second electrode 146, but is not limited thereto. . The connection electrode 147 may be formed on side surfaces of the first and second light emitting structures 120 and 130, but is not limited thereto.

The first insulating layer 148 is formed between the connecting electrode 147 and the sides of the first and second light emitting structures 120 and 130 to connect the connecting electrode 147, the conductive substrate 142, and the third electrode 146. The first and second light emitting structures 120 and 130 may be prevented from being shorted unnecessarily.

Meanwhile, the conductive substrate 142 may extend laterally so that the conductive substrate 142 and the second electrode 146 may be connected to each other.

The second insulating layer 149 may be formed on sidewalls of the second light emitting structure 130 to prevent the first electrode 144 and the second light emitting structure 130 from being shorted unnecessarily.

That is, the second insulating layer 149 may be formed on the sidewall of the mesa-etched second light emitting structure 130 described above.

The first and second insulating layers 148 and 149 are electrically insulating materials such as SiO ₂ , SiO _x , SiO _x N _y , Si ₃ N ₄ , Al ₂ O ₃ , TiO _x , TiO ₂ , Ti, Al It may include any one of Cr, but is not limited thereto.

12 is a cross-sectional view of a light emitting device according to the embodiment.

Referring to FIG. 12, the light emitting device 100 according to the embodiment is formed between the first semiconductor layer 122, the second semiconductor layer 126, and the first and second semiconductor layers 122 and 126. The first light emitting structure 120 including the first active layer 124, the third semiconductor layer 132, the fourth semiconductor layer 136, and the third and the third light emitting structures formed on the first light emitting structure 120. And a second light emitting structure 130 including a second active layer 134 formed between the four semiconductor layers 132 and 136, and the second and third electrodes 144 and 146 may have a multilayer structure. .

Hereinafter, although the second electrode 146 is described, it is obvious that the present invention can be applied to the first electrode 144 as well as the second electrode 146.

Referring to FIG. 12, the second electrode 146 may include a bonding layer 146a, a reflective layer 146b, and a protective layer 146c. In addition, the wire bonding layer 146d may be further included to connect the wires when the light emitting device package (not shown) is manufactured as described below.

The reflective layer 146b may include silver alloy.

Since the reflective layer 146b includes silver (Ag) having high reflectivity, the reflectivity of the second electrode 146 may be improved and the luminous efficiency of the light emitting device 100 may be improved. In addition, by being made of a silver alloy, it is possible to prevent the point where Vf increases when the second electrode 146 is heat treated, and that the galvanic corrosion or the like occurs due to the contact potential difference or the like.

On the other hand, when the fourth semiconductor layer 136 is formed of an n-type semiconductor layer and the reflective layer 146b is formed of simple silver, it may be difficult for the second electrode 146 and the fourth semiconductor layer 136 to form ohmic contact. have. However, as the reflective layer 146b includes a silver alloy, high reflectivity by silver may be ensured, and at the same time, the third semiconductor layer 136 and the first second electrode 146 may form ohmic contacts.

Meanwhile, the silver alloy may include silver (Ag) and at least one of Cu, Re, Bi, Al, Zn, W, Sn, In, and Ni, but is not limited thereto. On the other hand, silver alloy is 100? To 700? It can be formed by performing an alloy in.

On the other hand, silver (Ag) may contain 50 wt% or more, but is not limited thereto.

The bonding layer 146a may be formed of at least one of Cr, Ti, V, Ta, and Al. The bonding layer 146a may improve adhesion between the second electrode 146 and the third semiconductor layer 136. It suppresses excessive diffusion and migration of silver contained in. In addition, the protective layer 146c may be formed of at least one of Cr, Ti, Ni, Pd, Pt, W, Co, and Cu, which suppresses excessive injection of external oxygen and excessive external diffusion of silver particles, It can prevent agglomeration and public phenomena.

Meanwhile, the bonding layer 146a, the reflective layer 146b, and the protective layer 146c may be sequentially deposited or formed at the same time, and the annealing process may be performed after the formation, but is not limited thereto. Meanwhile, only the bonding layer 146a and the reflective layer 146b may be sequentially deposited or simultaneously formed, but are not limited thereto. Meanwhile, when the bonding layer 146a and the reflective layer 146b are simultaneously formed and alloyed, they may be formed of one layer Ag _x M _y A _z (1 ≧ x ≧ 0.5).

When the second electrode 146 configured as described above is subjected to heat treatment, the second electrode 146 may be bonded to the fourth semiconductor layer 136 with low contact resistance and strong adhesive force.

In addition, galvanic corrosion due to heat treatment does not occur, and excessive diffusion of silver particles by heat treatment is prevented by the bonding layer 146a and the protective layer 146c, so that the second electrode 146 has a high light characteristic of silver. Reflectivity characteristics can be maintained.

Meanwhile, when the light emitting device 100 is mounted on a light emitting device package (not shown), the wire bonding layer 146d may be formed such that a wire connected to apply an external power source is bonded. The wire bonding layer 146d may include, for example, gold, but is not limited thereto.

Meanwhile, at least one of the second and third electrodes 144 and 146 may be a pad electrode.

13 and 14 are cross-sectional views of the light emitting device 100 according to the embodiment.

Referring to FIG. 13, the light emitting device according to the embodiment may include a first active layer formed between the first semiconductor layer 122, the second semiconductor layer 126, and the first and second semiconductor layers 122 and 126. A first light emitting structure 120 including 124, a third semiconductor layer 132, a fourth semiconductor layer 136, and third and fourth semiconductor layers formed on the first light emitting structure 120. A second light emitting structure 130 including a second active layer 134 is formed between the (132, 136), and the transparent electrode layer 170 may be formed on the second light emitting structure (130).

The transparent electrode layer 170 may include a light transmissive conductive material such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, but is not limited thereto.

By forming the transparent electrode layer 170 on the second light emitting structure 130, current spreading may be improved. Therefore, the current provided to the second light emitting structure 130 may be evenly spread so that the recombination rate between electrons and holes in the second active layer 134 may increase.

Meanwhile, as illustrated in FIG. 14, at least one region of the transparent electrode layer 170 may be removed to expose the fourth semiconductor layer 136 and the fourth semiconductor layer 136 and the second electrode 146 may be in contact with each other. It is not limited thereto.

In this case, the fourth semiconductor layer 136 and the second electrode 146 may form a Schottky junction. In this case, the metal material forming the second electrode 146 may have a higher work function than the fourth semiconductor layer 136. As the fourth semiconductor layer 136 and the second electrode 146 form a Schottky junction, the current supplied through the second electrode 146 is not concentrated under the second electrode 146, and the light transmissive electrode layer 170 is provided. Flow through) may improve current spreading.

15 is a cross-sectional view of a light emitting device 100 according to the embodiment.

Referring to FIG. 15, the light emitting device 100 according to the embodiment may be formed of a first semiconductor layer 122, a second semiconductor layer 126, and first and second semiconductor layers 122 126. The first light emitting structure 120 including the first active layer 124, the third semiconductor layer 132, the fourth semiconductor layer 136, and the third and fourth formed on the first light emitting structure 120 A second light emitting structure 130 including a second active layer 134 formed between the semiconductor layers 132 and 136, and several light transmitting structures 172, and a light transmissive structure on the second light emitting structure 130. The transparent electrode layer 170 may be formed on the structure 172.

The light transmissive structure 172 may be formed such that several structures having light transmissivity are arranged on the fourth semiconductor layer 136. The light-transmitting structure 172 may include, for example, materials of Al ₂ O ₃ , SiO ₂ , IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, and the like, but is not limited thereto.

The translucent structure 172 is formed by, for example, several particles having a predetermined size scattered on the fourth semiconductor layer 136, or a layer having a predetermined thickness and roughness formed on the fourth semiconductor layer! 36. It can be formed by this, but is not limited thereto. On the other hand, the light-transmitting structure 172 may be disposed having a predetermined pattern, or randomly distributed, but is not limited thereto.

Meanwhile, as illustrated in FIG. 15, the transparent electrode layer 170 may be formed on the transparent structure 172. The formation of the transmissive electrode layer 170 on the translucent structure 172 improves current spreading and prevents the translucent structure 172 from escaping from the fourth semiconductor layer 136 or damaging the translucent structure 172. Can be.

By forming several translucent structures 172 on the fourth semiconductor layer 136, the second uneven portion 174 having a predetermined roughness may be formed on the fourth semiconductor layer 136.

The second uneven portion 174 may be formed to have a regular shape and arrangement, and may be formed to have an irregular shape and arrangement, but is not limited thereto. The second uneven portion 174 is an uneven upper surface, and a plurality of irregular shapes are arranged or form a predetermined pattern to form at least one of a texture pattern, an uneven pattern, and an uneven pattern. It may include, but is not limited to.

The second concave-convex portion 174 may be formed to have various shapes such as a cylinder, a polygonal pillar, a cone, a polygonal pyramid, a truncated cone, a polygonal truncated cone, and preferably includes a horn shape.

The second uneven portion 174 forms a light extraction structure that prevents light generated from the first and second active layers 124 and 134 from being totally reflected on the upper surface of the second light emitting structure 130 to be reabsorbed or scattered. do. That is, the second uneven portion 174 may form an angle of incidence below the critical angle when light generated from the first and second active layers 124 and 134 is incident on the upper surface of the second light emitting structure 130.

As the second uneven portion 174 is formed on the top surface of the second light emitting structure 130, light generated from the first and second active layers 124 and 134 is totally reflected at the top surface of the second light emitting structure 130. Since it can be prevented to be reabsorbed or scattered, it can contribute to the improvement of the light extraction efficiency of the light emitting device 100.

16 is a cross-sectional view of a light emitting device according to the embodiment.

Referring to FIG. 16, the light emitting device 100 according to the embodiment is formed between the first semiconductor layer 122, the second semiconductor layer 126, and the first and second semiconductor layers 122 and 126. The first light emitting structure 120 including the first active layer 124, the third semiconductor layer 132, the fourth semiconductor layer 136, and the third and the third light emitting structures formed on the first light emitting structure 120. And a second light emitting structure 130 including a second active layer 134 formed between the four semiconductor layers 132 and 136, and the first and second light emitting structures 120 and 130 may each have an electron limiting layer ( EBL: Electron Blocking Layer (128, 138) may be included.

For example, as illustrated in FIG. 16, the first light emitting structure 120 may include a first electron blocking layer 128, and the second light emitting structure 130 may include a second electron blocking layer 138. .

The first and second electron confinement layers 128 and 138 have relatively larger bandgaps than the first and second active layers 124 and 134, thereby implanting from the first and third semiconductor layers 122 and 132. The electrons can be prevented from being injected into the second and fourth semiconductor layers 126 and 136 without being recombined in the first and second active layers 124 and 134. Accordingly, the probability of recombination of electrons and holes in the first and second active layers 124 and 134 may be increased, and leakage current may be prevented.

Meanwhile, the above-described first and second electron limiting layers 128 and 138 may have a bandgap larger than that of the barrier layers included in the first and second active layers 124 and 134, for example, p-type AlGaN. It may be formed of a semiconductor layer including Al, such as, but not limited to.

Meanwhile, the first and second electron limiting layers 128 and 138 may be disposed between the first semiconductor layer 122 and the second semiconductor layer 126, and between the third semiconductor layer 132 and the fourth semiconductor layer 136. Can be formed. In FIG. 16, a first electron limiting layer 128 is formed between the second semiconductor layer 126 and the first active layer 124, and second electrons are formed between the fourth semiconductor layer 136 and the second active layer 134. The restriction layer 138 is formed, but is not limited thereto. That is, as shown in FIG. 17, the first electron limiting layer 128 is formed between the first semiconductor layer 122 and the first active layer 124, and the third semiconductor layer 132 and the second active layer 134 are formed. The second electron limiting layer 138 may be formed between the layers, but is not limited thereto.

18 is a cross-sectional view of a light emitting device according to the embodiment, FIG. 19 is an enlarged cross-sectional view showing a region B of FIG. 18, and FIGS. 20 and 21 are diagrams showing energy band diagrams of the light emitting device according to the embodiment.

Referring to FIG. 18, the second active layer 134 of the light emitting device 100 may have a multi-quantum well structure. For example, the second active layer 134 may include first to third well layers Q1, Q2, and Q3 and first to third barrier layers B1, B2, and B3.

Hereinafter, the multi-quantum well structure of the second active layer 134 will be described, but the first active layer 124 may also have a multi-quantum well structure, and the following description is also the same for the first active layer 124.

The first to third well layers Q1, Q2, and Q3 and the first to third barrier layers B1, B2, and B3 may have a structure in which they are alternately stacked as shown in FIG. 21.

Meanwhile, in FIG. 19, the first to third well layers Q1, Q2, and Q3 and the first to third barrier layers B1, B2, and B3 are formed, respectively, and the first to third barrier layers B1, B2, B3) and the first to third well layers Q1, Q2, and Q3 are alternately formed, but are not limited thereto, and the well layers Q1, Q2, and Q3 and the barrier layers B1, B2, and B3 may be alternately formed. ) May be formed to have any number, and the arrangement may also have any arrangement. In addition, as described above, the composition ratios, band gaps, and thicknesses of the materials forming the respective well layers Q1, Q2, and Q3, and the respective barrier layers B1, B2, and B3 may be different from each other. It is not limited as shown in 19.

20 to 21, the band gap of the third well layer Q3 may be larger than the band gaps of the first and second well layers Q1 and Q2.

The band gap of the third well layer Q3 adjacent to the fourth semiconductor layer 136, which provides holes in the second active layer 134, is larger than the band gaps of the first and second well layers Q1 and Q2. As it is formed, the movement of holes can be facilitated. Accordingly, the efficiency of injecting holes into the first and second well layers Q1 and Q2 and the overall hole injection efficiency may be increased.

In addition, since the band gap of the third well layer Q3 is larger than the first and second well layers Q1 and Q2 and smaller than the barrier layers B1, B2 and B3, the barrier layers B1 and B2 having a large band gap are provided. , B3) and the second semiconductor layer 126 and the band gap between the small band gap well layers Q1, Q2, and Q3, to alleviate interlayer stress generation, thereby further improving the reliability of the light emitting device 100. Can be.

On the other hand, in as described above, the well layer (Q1, Q2, Q3) is _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1) It may have a composition formula. The higher the In content of the well layers Q1, Q2, and Q3, the smaller the band gap. On the contrary, the smaller the In content of the well layers Q1, Q2, and Q3, the smaller the band gap of the well layers Q1, Q2, and Q3. Can be large.

For example, the In content of the third well layer Q3 may be 90% to 99% of the In content of the first and second well layers Q1 and Q2. When the In content is less than 90%, the difference in lattice constant between the first and second well layers Q1 and Q2 becomes larger in the band gap of the third well layer Q3, and the crystallinity is lowered. In addition, when In content is 99% or more, there is no big difference with 1st and 2nd well layers Q1 and Q2, and it does not have a big influence on hole injection and hardening improvement. The ratio may be any one of a molar ratio, a volume ratio, and a mass ratio, but is not limited thereto.

On the other hand, the piezoelectric polariziton generated by the stress due to the lattice constant difference and the orientation between the semiconductor layers may occur in the semiconductor layer. The semiconductor material forming the light emitting element has a large value of the piezoelectric coefficient and thus can cause very large polarization even at small strains. The electric field caused by the two polarizations changes the energy band structure of the quantum well structure, thereby distorting the distribution of electrons and holes. This effect is called the quantum confined stark effect (QCSE), which causes low internal quantum efficiency in light emitting devices that generate light by recombination of electrons and holes, and emits light such as red shift in the emission spectrum. It may adversely affect the electrical and optical characteristics of the device.

As it described above, the composition formula of the well layer (Q1, Q2, Q3) is _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1) The barrier layers B1, B2, and B3 may have a composition formula of In _a Al _b Ga _{1 -a- b} N (0≤a≤1, 0≤b≤1, 0≤a + b≤1). . The lattice constant of InN is larger than GaN, and as the In content included in the well layers Q1, Q2, and Q3 increases, the lattice constant of the well layers Q1, Q2, and Q3 increases, so that the barrier layers B1, B2, and B3 The difference in lattice constant between the well layers Q1, Q2, and Q3 increases, which results in more strain between the layers. Due to this strain, the polarization effect as described above is further increased to strengthen the internal electric field. Accordingly, the band bends according to the electric field, resulting in a pointed triangle potential well, and the shape where electrons or holes are concentrated in the triangle potential well. May occur. Therefore, the recombination rate of electrons and holes may decrease.

According to an embodiment, as the In content of the third well layer Q3 decreases to decrease the lattice constant, the lattice constant difference between the barrier layers B1, B2 and B3 and the third well layer Q3 may decrease. Can be. Therefore, the generation of the above-described triangle potential wells can be reduced, thus the recombination rate of electrons and holes can be increased, and the luminous efficiency of the light emitting device 100 can be improved.

In addition, the band gap of the third well layer Q3 adjacent to the fourth semiconductor layer 126 is large and has a high potential barrier, thereby providing a carrier (for example, a hole) provided in the second semiconductor layer 126. Resistivity can lead to hole diffusion. Recombination of electrons and holes occurs in a wider range over the area of the second active layer 134 through the path diffusion of holes, thereby improving the coupling ratio of electrons and holes, thus improving the luminous efficiency of the light emitting device 100. Can be.

On the other hand, the crystal defects due to the lattice constant difference between the growth substrate (not shown) on which the semiconductor layer is grown and the first light emitting structure 120 formed on the growth substrate (not shown) tend to increase along the growth direction. The fourth semiconductor layer 136 formed at the position spaced apart from the growth substrate (not shown) may have the largest crystal defect. Considering the fact that the hole mobility is lower than the electron mobility, the decrease in the hole injection efficiency due to the decrease in the crystallinity of the fourth semiconductor layer 136 is the luminous efficiency of the light emitting device 100. Can be lowered.

However, as in the embodiment, since the band gap of the third well layer Q3 of the second active layer 134 is formed to be large, the propagation of crystal defects can be blocked, so that the crystal defects of the fourth semiconductor layer 136 can be improved. In addition, the luminous efficiency of the light emitting device 100 may be improved.

Meanwhile, as illustrated in FIG. 21, the band gaps of the first to third well layers Q1, Q2, and Q3 may be formed to be large in sequence.

That is, the content of In included in the first to third well layers Q1, Q2, and Q3 may be sequentially decreased from the first well layer Q1 to the third well layer Q3.

The holes of the first to third well layers Q1, Q2, and Q3 are formed as the well layers Q1, Q2, and Q3 have larger band gaps as they are adjacent to the fourth semiconductor layer 136 that injects holes. Injection efficiency may be improved, and thus, light emission efficiency of the light emitting device 100 may be improved.

In addition, as the band gaps are sequentially increased from the first well layer Q1 to the third well layer Q3, the well layers Q1, Q2, and Q3, the barrier layers B1, B2, and B3, and the third, The difference in the lattice constant between the fourth semiconductor layers 132 and 134 is alleviated, thereby reducing the occurrence of the triangle potential well, thus increasing the recombination rate of electrons and holes, and improving the luminous efficiency of the light emitting device 100. Can be.

On the other hand, the thickness of the well layer (not shown) of the first active layer 124, the thickness and the band gap size of the first to third well layers (Q1, Q2, Q3) of the second active layer 134 may be different from each other. Can be.

For example, the energy level formula of light generated in the well layer is as follows.

At this time, L corresponds to the thicknesses d1 and d2 of the well layer. Therefore, as the thicknesses of the first to third well layers Q1, Q2 and Q3 become thicker, the energy level of light generated in the first to third well layers Q1, Q2 and Q3 becomes lower.

The thickness of the well layer (not shown) of the first active layer 124 and the thickness of the first to third well layers Q1, Q2, and Q3 of the second active layer are formed to be different from each other, thereby forming the first light emitting structure 120. ) And the second light emitting structure 130 may generate light having different wavelengths. For example, the first light emitting structure 120 may generate blue light, and the second light emitting structure 130 may generate green light. Accordingly, the light emitting device 100 may emit light of a plurality of colors, and may generate predetermined light such as white light without using a separate photocatalyst such as a phosphor (not shown) through overlapping of the multicolored light.

22 is a cross-sectional view of a light emitting device according to the embodiment.

Referring to FIG. 3, a current blocking layer 180 (CBL) may be disposed between the conductive substrate 142 and the first light emitting structure 120.

The current limiting layer 180 may be formed using at least one of a material having electrical insulation, for example, a material having a lower electrical conductivity than the conductive substrate 142, and a material forming a Schottky contact with the first semiconductor layer 122. For example, it may include at least one of Si ₃ N ₄ , Al ₂ O ₃ , TiO _x , TiO ₂ , Ti, Al, Cr.

Since the current limiting layer 180 is disposed between the conductive substrate 142 and the first light emitting structure 120, current grouping may be prevented. The current limiting layer 180 may be plural, and at least one of the current limiting layers 180 may be at least one region perpendicular to the first electrode 144 that may be formed on the third semiconductor layer 132. Can be arranged to overlap.

For example, the current limiting layer 180 may be formed to form a groove in at least one region of the conductive substrate 142 and be disposed in the groove region, but is not limited thereto.

23 is a cross-sectional view of a light emitting device according to the embodiment.

Referring to FIG. 23, a channel layer 182 may be formed between an outer region of the light emitting structure 142 and the conductive substrate 142.

The channel layer 182 may be disposed in a channel region that is a peripheral region of the light emitting device. The channel layer 182 may, for example, form a groove in at least one region of the conductive substrate 142 and be disposed in the groove region.

The channel layer 182 may be formed in a pattern of a loop shape, a ring shape, or a frame shape around the lower surface of the first semiconductor layer 122. The channel layer 182 may include a continuous pattern or a discontinuous pattern shape, or may be formed on a path of a laser irradiated to the channel region in the manufacturing process.

The channel layer 182 may be selected from a material of an oxide, a nitride, or an insulating layer, and for example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), and indium aluminum zinc oxide (AZO) ), Indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), SiO2, SiOx, SiOxNy, Si3N4, Al2O3, TiO2 And the like.

The channel layer 182 may prevent the first and second light emitting structures 120 and 130 from being damaged when the light emitting device 100 is separated by a predetermined method. For example, the channel layer 182 may prevent the first and second light emitting structures 120 and 130 from being damaged when the conductive substrate 142 is separated into individual device units.

24 and 25 are conceptual views illustrating a circuit diagram of an illumination system 200 including a light emitting device 100 according to an embodiment.

24 and 25, the lighting system 200 including the light emitting device 100 according to the embodiment includes at least one light emitting device 100, and each light emitting device 100 is configured to be connected in series. Can be.

Each light emitting device 100 may be connected to a substrate (not shown) through a predetermined circuit pattern to form a light emitting device array. In this case, the light emitting device 100 is mounted on, for example, a light emitting device package 500 to be described later, and the light emitting device package 500 is configured to be mounted on a substrate (not shown), or a light emitting device on a substrate (not shown). It may be configured in the form of (COB: Chip on Board) is mounted 100, but is not limited thereto.

In addition, the lighting system 200 including the light emitting device 100 according to the embodiment may include, for example, a lighting device such as a lamp, a street lamp, a backlight unit, but is not limited thereto.

The light emitting device 100 according to the embodiment includes a first light emitting structure 120 and a second light emitting structure 130 which can generate light in the reverse voltage and the constant voltage phase of the AC power, respectively, When the AC power is connected to the system 200, the light emitting device 100 may emit light for both the reverse voltage and the constant voltage phase. Therefore, flickering of the lighting system 200 may occur when the reverse voltage is applied and the constant voltage is applied. Can be prevented.

In addition, each light emitting device 100 can drive in both a reverse voltage and a constant voltage phase, and a current path corresponding to each case is formed, and thus, for example, as shown in FIGS. 24 and 25, several light emitting devices ( 100 may be configured to be connected in series to an AC power source. Therefore, the connection of several light emitting devices 100 may be facilitated, and the output of the lighting system 200 may be improved and output may be adjusted.

26 to 28 are a perspective view and a cross-sectional view showing a light emitting device package according to the embodiment.

26 to 28, the light emitting device package 500 may include a body 510 having a cavity 520, first and second lead frames 540 and 550 mounted on the body 510, and a first one. And a light emitting device 530 electrically connected to the second lead frames 540 and 550, and a resin layer (not shown) filled in the cavity 520 to cover the light emitting device 530.

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

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

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

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

The light emitting device 530 is mounted on the first lead frame 540 and may be, for example, a light emitting device emitting light of red, green, blue, white, or UV (ultraviolet) light emitting device emitting ultraviolet light. But it is not limited thereto. In addition, one or more light emitting elements 530 may be mounted.

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

Meanwhile, the light emitting device 530 according to the embodiment may include first and second light emitting structures (not shown), and the first and second light emitting structures (not shown) may be driven in a reverse bias and a forward bias, respectively. . Therefore, the light emitting device package 500 according to the embodiment can emit light in both the reverse bias and the forward bias in the AC power source, the luminous efficiency can be improved.

In addition, since a separate ESD device is not required in the AC power source, light loss by the ESD device in the light emitting device package 500 may be prevented.

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

The resin layer (not shown) may be formed of silicon, epoxy, and other resin materials, and may be formed by filling the cavity 520 and then UV or heat curing the same.

In addition, the resin layer (not shown) may include a phosphor, and the kind of the phosphor may be selected by the wavelength of the light emitted from the light emitting device 530 so that the light emitting device package 500 may realize the white light.

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

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

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

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

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

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

28, the light emitting device package 500 according to the embodiment may include an optical sheet 580, and the optical sheet 580 may include a base portion 582 and a prism pattern 584. Can be.

The base portion 582 is made of a transparent material having excellent thermal stability as a support for forming the prism pattern 584. For example, the base portion 582 is made of polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polystyrene, and polyepoxy. It may be made of any one selected from the group, but is not limited thereto.

In addition, the base portion 582 may include a phosphor (not shown). As an example, the base portion 582 may be formed by curing the phosphor (not shown) evenly in a state in which the base portion 582 is uniformly dispersed. As such, when the base portion 582 is formed, the phosphor (not shown) may be uniformly distributed over the base portion 582.

On the other hand, a three-dimensional prism pattern 584 that refracts and collects light may be formed on the base portion 582. The material constituting the prism pattern 584 may be acrylic resin, but is not limited thereto.

The prism pattern 584 includes a plurality of linear prisms arranged in parallel with one another in one direction on one surface of the base portion 582, and a vertical cross section of the linear prism in the axial direction may be triangular.

Since the prism pattern 584 has an effect of condensing light, when the optical sheet 580 is attached to the light emitting device package 500, the linearity of the light may be improved, and thus the brightness of the light of the light emitting device package 500 may be improved. have.

On the other hand, the prism pattern 584 may include a phosphor (not shown).

The phosphor (not shown) is uniformly formed in the prism pattern 584 by forming the prism pattern 584 in a dispersed state, for example, by mixing with an acrylic resin to form a paste or slurry, and then forming the prism pattern 584. Can be included.

As such, when the phosphor (not shown) is included in the prism pattern 584, the uniformity and distribution of the light of the light emitting device package 500 may be improved, and in addition to the light condensing effect by the prism pattern 584, the phosphor (not shown) may be used. Due to the light scattering effect, the directivity of the light emitting device package 500 can be improved.

A plurality of light emitting device packages 500 according to the embodiment may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, or the like, which is an optical member, may be disposed on an optical path of the light emitting device package 500. Such a light emitting device package, a substrate, and an optical member can function as a light unit. Another embodiment may be implemented as a display device, an indicator device, or a lighting system including the light emitting device or the light emitting device package described in the above embodiments, and for example, the lighting system may include a lamp or a street lamp.

29 is a perspective view illustrating a lighting device including a light emitting device package according to an embodiment, and FIG. 30 is a cross-sectional view illustrating a C-C 'cross section of the lighting device of FIG. 29.

29 and 30, the lighting device 600 may include a body 610, a cover 630 fastened to the body 610, and a closing cap 650 located at both ends of the body 610. have.

A light emitting device module 640 is coupled to a lower surface of the body 610. The body 610 is electrically conductive so that heat generated from the light emitting device package 644 can be emitted to the outside through the upper surface of the body 610. [ And a metal material having an excellent heat dissipation effect.

The light emitting device package 644 may be mounted on the PCB 642 in a multi-color, multi-row manner to form an array. The light emitting device package 644 may be mounted at equal intervals or may be mounted with various spacings as required. As the PCB 642, MPPCB (Metal Core PCB) or FR4 material PCB can be used.

On the other hand, the light emitting device package 644 according to the embodiment includes a light emitting device (not shown), the light emitting device (not shown) includes a first and a second light emitting structure (not shown), the first and second The light emitting structure (not shown) may be driven at reverse bias and forward bias, respectively. Therefore, the lighting device 600 according to the embodiment can emit light in both the reverse bias and the forward bias in the AC power source, the flicker phenomenon can be eliminated and the luminous efficiency can be improved.

The cover 630 may be formed in a circular shape so as to surround the lower surface of the body 610, but is not limited thereto.

The cover 630 protects the internal light emitting element module 640 from foreign substances or the like. The cover 630 may include diffusion particles so as to prevent glare of light generated in the light emitting device package 644 and uniformly emit light to the outside, and may include at least one of an inner surface and an outer surface of the cover 630 A prism pattern or the like may be formed on one side. Further, the phosphor may be applied to at least one of the inner surface and the outer surface of the cover 630.

On the other hand, since the light generated from the light emitting device package 644 is emitted to the outside through the cover 630, the cover 630 should have excellent light transmittance, and has sufficient heat resistance to withstand the heat generated from the light emitting device package 644. The cover 630 is preferably formed of a material including polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), or the like. .

The finishing cap 650 is located at both ends of the body 610 and can be used to seal the power supply unit (not shown). In addition, the finishing cap 650 is provided with the power supply pin 652, so that the lighting apparatus 600 according to the embodiment can be used immediately without a separate device on the terminal from which the conventional fluorescent lamp is removed.

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

31 is an edge-light method, the liquid crystal display 700 may include a liquid crystal display panel 710 and a backlight unit 770 for providing light to the liquid crystal display panel 710.

The liquid crystal display panel 710 can display an image using light provided from the backlight unit 770. The liquid crystal display panel 710 may include a color filter substrate 712 and a thin film transistor substrate 714 facing each other with a liquid crystal therebetween.

The color filter substrate 712 can realize the color of an image to be displayed through the liquid crystal display panel 710.

The thin film transistor substrate 714 is electrically connected to a printed circuit board 718 on which a plurality of circuit components are mounted via a driving film 717. The thin film transistor substrate 714 may apply a driving voltage provided from the printed circuit board 718 to the liquid crystal in response to a driving signal provided from the printed circuit board 718. [

The thin film transistor substrate 714 may include a thin film transistor and a pixel electrode formed as a thin film on another substrate of a transparent material such as glass or plastic.

The backlight unit 770 may include a light emitting device module 720 for outputting light, a light guide plate 730 for changing the light provided from the light emitting device module 720 into a surface light source, and providing the light to the liquid crystal display panel 710. Reflective sheet for reflecting the light emitted from the back of the light guide plate 730 and the plurality of films 752, 766, 764 to uniform the luminance distribution of the light provided from the 730 and improve the vertical incidence ( 740.

The light emitting device module 720 may include a PCB substrate 722 for mounting a plurality of light emitting device packages 724 and a plurality of light emitting device packages 724 to form an array.

On the other hand, the backlight unit 770 according to the embodiment includes a light emitting device (not shown), the light emitting device (not shown) includes a first and second light emitting structure (not shown), the first and second light emission The structure (not shown) can drive in reverse bias and forward bias, respectively. Therefore, the backlight unit 770 according to the embodiment can emit light in both the reverse bias and the forward bias in the AC power source, the flicker phenomenon can be eliminated and the luminous efficiency can be improved.

Meanwhile, the backlight unit 770 includes a diffusion film 766 for diffusing light incident from the light guide plate 730 toward the liquid crystal display panel 710, and a prism film 750 for condensing the diffused light to improve vertical incidence. It may be configured as), and may include a protective film 764 for protecting the prism film 750.

32 is an exploded perspective view of a liquid crystal display including the light emitting device according to the embodiment. However, the parts shown and described in FIG. 31 will not be repeatedly described in detail.

32 is a direct view, the liquid crystal display device 800 may include a liquid crystal display panel 810 and a backlight unit 870 for providing light to the liquid crystal display panel 810.

Since the liquid crystal display panel 810 is the same as that described with reference to FIG. 31, a detailed description thereof will be omitted.

The backlight unit 870 includes a plurality of light emitting element modules 823, a reflective sheet 824, a lower chassis 830 in which the light emitting element module 823 and the reflective sheet 824 are accommodated, And a plurality of optical films 860. The diffuser plate 840 and the plurality of optical films 860 are disposed on the light guide plate 840. [

LED Module 823 A plurality of light emitting device packages 822 and a plurality of light emitting device packages 822 may be mounted to include a PCB substrate 821 to form an array.

On the other hand, the backlight unit 870 according to the embodiment includes a light emitting device (not shown), the light emitting device (not shown) includes a first and second light emitting structure (not shown), the first and second light emission The structure (not shown) can drive in reverse bias and forward bias, respectively. Therefore, the backlight unit 870 according to the embodiment can emit light in both the reverse bias and the forward bias in the AC power source, the flicker phenomenon can be eliminated and the luminous efficiency can be improved.

The reflective sheet 824 reflects light generated from the light emitting device package 822 in a direction in which the liquid crystal display panel 810 is positioned, thereby improving light utilization efficiency.

Light generated in the light emitting element module 823 is incident on the diffusion plate 840 and an optical film 860 is disposed on the diffusion plate 840. The optical film 860 may include a diffusion film 866, a prism film 850, and a protective film 864.

Meanwhile, the light emitting device according to the embodiment is not limited to the configuration and method of the embodiments described above, but the embodiments may be modified so that all or some of the embodiments may be selectively And may be configured in combination.

In addition, while the preferred embodiments have been shown and described, the present invention is not limited to the specific embodiments described above, and the present invention is not limited to the specific embodiments described above, and the present invention may be used in the art without departing from the gist of the invention as claimed in the claims. Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

100 light emitting element 120 first light emitting structure
122: first semiconductor layer 124: first active layer
126: second semiconductor layer 130: second light emitting structure
132: third semiconductor layer 134: second active layer
136: fourth semiconductor layer 142: conductive substrate
144: first electrode 146: second electrode

Claims (16)

Conductive substrate;
A first light emitting structure including a first semiconductor layer, a second semiconductor layer, and a first active layer formed between the first and second semiconductor layers on the conductive substrate;
A second light emitting structure on the first light emitting structure and including a third semiconductor layer, a fourth semiconductor layer, and a second active layer formed between the third and fourth semiconductor layers;
A first electrode electrically connected with the second and third semiconductor layers; And
And a second electrode electrically connected to the fourth semiconductor layer.
The first semiconductor layer is electrically connected to the conductive substrate,
The first and third semiconductor layers are doped with a first conductivity type,
And the second and fourth semiconductor layers are doped with a second conductivity type. The method of claim 1,
The conductive substrate and the second electrode are electrically connected to each other,
The first light emitting structure and the second light emitting structure,
Light emitting devices connected in parallel to each other in a parallel structure. The method of claim 1,
The first conductivity type is n-type light emitting device. The method of claim 1,
The first to fourth semiconductor layer,
A light emitting device comprising a nitride semiconductor. The method of claim 1,
The first to fourth semiconductor layer,
A light emitting device comprising a zinc oxide semiconductor. The method of claim 1,
The conductive substrate,
Light emitting device having a multilayer structure. The method of claim 1,
The conductive substrate,
A light emitting device comprising at least one of an ohmic layer, a reflective layer, and a bonding layer. The method of claim 1,
The second light emitting structure is first mesa etched to expose at least one region of the upper surface of the third semiconductor layer,
The first electrode is formed on the exposed region of the third semiconductor layer. The method of claim 1,
Wherein the second electrode comprises:
The light emitting device formed on the fourth semiconductor layer. The method of claim 1,
And a connection electrode electrically connecting the second electrode and the conductive substrate.
The connection electrode is formed on the side of the first and second light emitting structure. The method of claim 10,
And a first insulating layer between the connection electrode and the first and second light emitting structures. The method of claim 1,
And a current limiting layer formed between the conductive substrate and the first semiconductor layer. The method of claim 12,
The current limiting layer,
The light emitting device overlapping at least one region perpendicular to the first electrode. The method of claim 1,
And a channel layer formed on the outer side of the conductive support substrate. Conductive substrate;
A first light emitting structure including a first semiconductor layer of a first conductivity type and a second semiconductor layer of a second conductivity type on the conductive substrate;
A second light emitting structure including a third semiconductor layer of a first conductivity type and a fourth semiconductor layer of a second conductivity type on the first light emitting structure;
A first electrode electrically connected to the fourth semiconductor layer;
A second electrode electrically connecting the second semiconductor layer and the third semiconductor layer;
The first electrode and the conductive substrate are connected to a first end of an AC power source,
The second electrode is connected to the second end of the AC power source,
A first current path is formed in the first light emitting structure during the first bias of the AC power source to generate first light,
A second current path is formed in the second light emitting structure during the second bias of the AC power source to generate second light;
The light emitting device of which the first bias and the second bias have opposite polarities. 16. The method of claim 15,
A connection electrode on sidewalls of the first light emitting structure and the second light emitting structure;
The connection electrode is a light emitting device for electrically connecting the conductive substrate and the first electrode.

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