KR20130065095A - Light emitting device - Google Patents

Abstract

PURPOSE: A light emitting device is provided to improve luminous efficiency by promoting the horizontal and vertical transfer of holes which move from a second conductive semiconductor layer to an active layer. CONSTITUTION: A second conductive semiconductor layer(126) is arranged on a first conductive semiconductor layer(122). An active layer(124) is arranged between the first conductive semiconductor layer and the second conductive semiconductor layer. An electron barrier layer(125-1) is arranged between the active layer and the second conductive semiconductor layer. The electron barrier layer includes at least one current spreading layer(201-1-201-n) having a superlattice structure. The current spreading layer includes a first horizontal transfer layer(210-1-210-n) and a first vertical transfer layer(220-1-220-n).

Description

[0001]

Embodiments relate to a light emitting device, and a light emitting device package, a lighting device, and a display device including the same.

Light Emitting Diodes (LEDs) using Group 3-5 or 2-6 compound semiconductor materials of semiconductors can realize various colors such as red, green, blue and ultraviolet rays through the development of thin film growth technology and device materials. Efficient white light can be realized by using fluorescent materials or combining colors, and has the advantages of low power consumption, semi-permanent life, fast response speed, safety and environmental friendliness compared to conventional light sources such as fluorescent and incandescent lamps. For the structure of such a light emitting device can be referred to Patent Publication No. 10-2009-0002241.

Therefore, a transmission module of the optical communication means, a light emitting diode backlight replacing a cold cathode fluorescent lamp (CCFL) constituting a backlight of an LCD (Liquid Crystal Display) display device, a white light emitting element capable of replacing a fluorescent lamp or an incandescent lamp Diode lighting, automotive headlights, and traffic lights.

The embodiment provides a light emitting device capable of improving luminous efficiency and reducing operating voltage.

The light emitting device according to the embodiment is disposed between a first conductivity type semiconductor layer, a second conductivity type semiconductor layer disposed on the first conductivity type semiconductor layer, the first conductivity type semiconductor layer, and the second conductivity type semiconductor layer. And an electron blocking layer disposed between the active layer and the second conductive semiconductor layer, wherein the electron blocking layer includes at least one first horizontal transport layer, and the at least one first horizontal transport layer includes: A first layer having a composition of AlN, a second layer having a composition of GaN, and a third layer having a composition of Al _x Ga _(1-x) N (0 <x <1).

The first layer is located between the active layer and the second conductivity type semiconductor layer, the second layer is located between the first layer and the second conductivity type semiconductor layer, and the third layer is located between the second layer and the second layer. The second conductive semiconductor layer may be positioned between the second conductive semiconductor layer. The at least one first horizontal transport layer may have a superlattice structure.

The composition of the third layer is Al _x Ga _(1-x) N (0 <x≤0.22), and the content (x) of aluminum in the third layer is from the first conductivity type semiconductor layer to the second conductivity type. As it progresses toward the semiconductor layer, it may increase. The second layer may be an undoped layer. The third layer may be doped with a p-type dopant.

The electron blocking layer is positioned between the third layer and the second conductive semiconductor layer, and has a composition of Al _y Ga _(1-y) N (0 <y <1), and the content of aluminum (Al) (y). The semiconductor device may further include a first vertical transport layer that decreases from the first conductive semiconductor layer toward the second conductive semiconductor layer.

The composition of the first vertical transport layer may be Al _y Ga _(1-y) N (0 < _y ≦ 0.22). The electron blocking layer is located between the first horizontal transport layer and the first vertical transport layer, a fourth layer having a composition of AlN, a fifth layer having a composition of GaN, between the fourth layer and the first vertical transport layer, And a second vertical transport layer between the fifth layer and the first vertical transport layer, the second vertical transport layer including a sixth layer having a composition of Al _a Ga _(1-a) N (0 <a ≦ 0.22). .

The content x of the aluminum of the sixth layer may increase as the direction of the second conductive semiconductor layer moves from the first conductive semiconductor layer. The fifth layer may be an undoped layer, and the sixth layer may be doped with a p-type dopant.

The electron blocking layer is positioned between the first vertical transport layer and the second conductive semiconductor layer, and has a composition of Al _y Ga _(1-z) N (0 <z <1), and the content of aluminum (Al) (z). ) May further include a second vertical transport layer that decreases from the first conductivity type semiconductor layer toward the second conductivity type semiconductor layer. The composition of the second vertical transport layer may be Al _z Ga _(1-z) N (0 < _z ≦ 0.22). The maximum value of the aluminum content (z) of the second vertical transport layer may be less than or equal to the maximum value of the aluminum content (y) of the first vertical transport layer.

An embodiment of the light emitting device may include a substrate disposed under the first conductive semiconductor layer, a conductive layer disposed on the second conductive semiconductor layer, a first electrode disposed on the first conductive semiconductor layer, And a second electrode disposed on the conductive layer.

Another embodiment of the light emitting device may further include an ohmic layer disposed under the second conductive semiconductor layer, a reflective layer disposed under the ohmic layer, and a first electrode disposed on the first conductive semiconductor layer. Can be.

The embodiment can improve the luminous efficiency and reduce the operating voltage.

1 is a cross-sectional view of a light emitting device according to an embodiment.
FIG. 2 illustrates a first embodiment of the electron blocking layer illustrated in FIG. 1.
FIG. 3 shows an energy band diagram of the electron blocking layer shown in FIG. 2.
4 illustrates a second embodiment of the electron blocking layer illustrated in FIG. 1.
FIG. 5 shows an energy band diagram of the electron blocking layer shown in FIG. 4.
FIG. 6 illustrates a third embodiment of the electron blocking layer illustrated in FIG. 1.
FIG. 7 shows an energy band diagram of the electron blocking layer shown in FIG. 6.
8 illustrates a light emitting device according to another embodiment.
9 illustrates a light emitting device package according to an embodiment.
10 is an exploded perspective view of a lighting device including a light emitting device package according to an embodiment.
11 illustrates a display device including a light emitting device package according to an exemplary embodiment.

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

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

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size of each component does not fully reflect its actual size. Hereinafter, a light emitting device according to an embodiment will be described with reference to the accompanying drawings.

1 is a sectional view of a light emitting device 100 according to an embodiment. Referring to FIG. 1, the light emitting device 100 includes a substrate 110, a first conductive semiconductor layer 122, an active layer 124, an electron blocking layer 125, and a second conductive semiconductor. The light emitting structure 120 includes a layer 126, a conductive layer 130, a first electrode 142, and a second electrode 144.

The substrate 110 supports the light emitting structure 120. The substrate 110 may be formed of a material suitable for growing a semiconductor material. In addition, the substrate 110 may be formed of a material having excellent thermal conductivity, and may be a conductive substrate or an insulating substrate. For example, the substrate 110 may be sapphire (Al ₂ O ₃ ) or a material including at least one of GaN, SiC, ZnO, Si, GaP, InP, Ga ₂ O ₃ , GaAs. Unevenness may be formed on the upper surface of the substrate 110 to improve light extraction.

A buffer layer (not shown) may be disposed between the first conductivity type semiconductor layer 122 and the substrate 110 in order to alleviate the lattice mismatch caused by the difference in the lattice constant between the substrate 110 and the light emitting structure 120. . The buffer layer may be a nitride semiconductor including a Group 3 element and a Group 5 element. For example, the buffer layer may include at least one of InAlGaN, GaN, AlN, AlGaN, and InGaN. The buffer layer may be a single layer or a multi-layer structure, and a Group 2 element or a Group 4 element may be doped with an impurity.

In addition, an undoped semiconductor layer (not shown) may be interposed to improve crystallinity of the first conductive semiconductor layer 122. The undoped semiconductor layer may be the same as the first conductive semiconductor layer 122 except that the n-type dopant is not doped and thus has a lower electrical conductivity than the first conductive semiconductor layer 122.

The light emitting structure 120 is disposed on the substrate 110, and generates light. The light emitting structure 120 includes a second conductive semiconductor layer 126, an electron blocking layer 125, an active layer 124, and a first conductive semiconductor layer 122 to expose a portion of the first conductive semiconductor layer 122. ) May be a partially etched structure.

The conductive layer 130 is disposed on the second conductive semiconductor layer, and not only reduces total reflection but also has good light transmittance, so that the extraction efficiency of light emitted from the active layer 124 to the second conductive semiconductor layer 126 may be improved. Can be increased.

The conductive layer 130 may be formed of a transparent conductive oxide, such as indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), indium aluminum zinc oxide (IZAZO), or IGZO (IGZO). Indium Gallium Zinc Oxide (IGTO), Indium Gallium Tin Oxide (IGTO), Aluminum Zinc Oxide (AZO), Antimony Tin Oxide (ATO), Gallium Zinc Oxide (GZO), IrOx, RuOx, RuOx / ITO, Ni, Ag, Ni / IrOx / Au, or Ni / IrOx / Au / ITO can be used to form a single layer or multiple layers.

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

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

The active layer 124 is disposed between the first conductive semiconductor layer 122 and the second conductive semiconductor layer 126. The active layer 124 is formed by energy generated in the process of recombination of electrons provided from the first conductivity type semiconductor layer 122 and holes provided from the second conductivity type semiconductor layer 126. Can produce light.

The active layer 124 is _{In x Al y Ga 1 -x- y} N may be a semiconductor having a composition formula of (0≤x≤1, 0≤y≤1, 0≤x + y≤1 ), the active layer 124 Is a quantum well including a quantum well layer (QW1 to QWn, a natural number with n≥1, see FIG. 3) and a quantum barrier layer (QB1 to QBm, a natural number with m≥1, see FIG. 3) alternately arranged one or more times. It may be a structure. For example, the active layer 124 may be a multi quantum well (MQW) structure. The energy band gap of the quantum barrier layers (QB1 to QBm, a natural number with m ≧ 1, see FIG. 3) may be greater than the energy band gap of the quantum well layers (QW1 to QWn, natural number with n ≧ 1, see FIG. 3).

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

The electron blocking layer 125 is disposed between the active layer 124 and the second conductive semiconductor layer 126, and electrons injected from the first conductive semiconductor layer 122 into the active layer 124 are second conductive semiconductors. It prevents leakage current by blocking the overflow to the layer.

The energy band gap of the electron blocking layer 125 may be larger than the energy band gap of the quantum barrier layer.

FIG. 2 shows a first embodiment 125-1 of the electron blocking layer 125 shown in FIG. 1, and FIG. 3 shows an energy band diagram of the electron blocking layer 125-1 shown in FIG. 2.

2 and 3, the electron blocking layer 125-1 includes at least one current spreading layer 201-1 to 201-n having a superlattice, a natural number of n ≧ 1.

The current spreading layers 201-1 to 201-n (natural numbers of n≥1) may include a first lateral transport layer (210-1 to 210-n, natural numbers of n≥1), and a first vertical transport layer (vertical transport). layer, 220-1 to 220-n, and a natural number of n≥1).

The first horizontal transport layers 210-1 to 210-n, and a natural number of n ≧ 1, may serve to distribute a current flowing from the second electrode 144 to the first electrode 142 in a lateral direction. have. The horizontal direction 102 may be a direction perpendicular to the direction from the second conductive semiconductor layer 126 to the first conductive semiconductor layer 122.

The first horizontal transport layer 210-1 to 210-n (a natural number of n≥1) is a first layer having a composition of AlN (212-1 to 212-n, a natural number of n≥1), and a second layer having a composition of GaN (214-1 to 214-n, a natural number with n≥1), and a third layer 216-1 to 216-n, n≥ with a composition of Al _x Ga _(1-x) N (0 <x≤0.22) 1 natural number).

The thicknesses of the first layers 212-1 to 212-n and n ≧ 1 may be 1 nm to 3 nm, and the thicknesses of the second layers 214-1 to 214-n and n ≧ 1 may be 2 nm. It may be ~ 4nm, the thickness of the third layer (216-1 to 216-n, n≥1 natural number) may be 5nm or less. In addition, the thicknesses of the second layers 214-1 to 214-n and n≥1 are greater than the thicknesses of the first layers 212-1 to 212-n and n≥1 and the third layer 216. -1 to 216-n, a natural number of n≥1) may be smaller than, but is not limited to.

The second layer (214-1 to 214-n, n≥1 natural number) may be an undoped layer, and the third layer (216-1 to 216-n, n≥1 natural number) is p-type The dopant (eg, Mg, Zn, Ca, Sr, Ba) may be doped p-Al _x Ga _(1-x) N (0 <x≤0.22). In addition, the content (x) of aluminum (Al) contained in the third layers 216-1 to 216-n, a natural number of n≥1, is from the first conductive semiconductor layer 122 to the second conductive semiconductor layer 126. As it progresses toward), it may increase linearly or nonlinearly.

First layer 212-1 through 212-n, n≥1 natural number, second layer 214-1 through 214-n, n≥1 natural number, and third layer 216-1 through 216-n , the first layer (212-1 to 212-n, n≥1 natural number) and the third layer (216-1 to 216-n, n≥1 by the influence of the composition and polarization between n≥1 natural number) Phosphorus), a two-dimensional hole gas region 10 having a low mobility in the vertical direction 101 and a high mobility in the horizontal direction 102 may be formed.

The vertical direction 101 may be a direction from the second conductivity type semiconductor layer 126 to the first conductivity type semiconductor layer 122, and the horizontal direction 102 may be a direction perpendicular to the vertical direction 101. .

In general, due to the low mobility of the holes, the light emitting efficiency of the large-area high-output light emitting device is difficult to disperse the holes in the horizontal direction, so that the luminous efficiency is reduced. As a result, the two-dimensional hole gas region 10 is formed, whereby the holes are easily dispersed in the horizontal direction 102, so that the luminous efficiency can be improved.

The composition of the first vertical transport layers 220-1 to 220-n, a natural number of n ≧ 1, may be Al _y Ga _(1-y) N (0 < _y ≦ 0.22), and the content of aluminum (Al) may be ) May decrease linearly or nonlinearly from the first conductive semiconductor layer 122 toward the second conductive semiconductor layer 126.

The thickness of the first vertical transport layers 220-1 to 220-n and a natural number of n ≧ 1 may be 5 nm or less. The thickness of the first vertical transport layers 220-1 to 220-n, and natural numbers of n≥1 may be the same as the thickness of the third layers 216-1 to 216-n, natural numbers of n≥1, but is not limited thereto. It doesn't happen.

Since the aluminum (Al) content (y) of the first vertical transport layers 220-1 to 220-n (n = 1 natural number) gradually decreases, the first vertical transport layers 220-1 to 220-n, n≥1. Phosphorus natural number) may have a barrier with a gentle slope. Therefore, the embodiment can easily move the hole in the vertical direction 101 in the hole injection side, thereby improving the hole injection efficiency to improve the luminous efficiency and reduce the operating voltage.

As a result, as described above, the embodiment may improve transport in the vertical and horizontal directions of holes passing from the second conductivity-type semiconductor layer 126 to the active layer 124, thereby improving luminous efficiency and decreasing operating voltage. have.

4 shows a second embodiment 125-2 of the electron blocking layer 125 shown in FIG. 1, and FIG. 5 shows an energy band diagram of the electron blocking layer 125-2 shown in FIG. 4. The same reference numerals as those of Fig. 2 and Fig. 3 denote the same configuration, and the content overlapping with the above description will be omitted or briefly described.

4 and 5, the electron blocking layer 125-2 includes at least one current spreading layer 301-1 to 301-n having a superlattice, a natural number of n ≧ 1.

The current spreading layers 301-1 to 301-n, and a natural number of n≥1, include the first horizontal transport layers 210-1 to 210-n and a natural number of n≥1, and the second horizontal transport layers 310-1 to 310-n. , n ≧ 1, and a first vertical transport layer 220-1 to 220-n, and n ≧ 1.

The composition and thickness of the second horizontal transport layers 310-1 to 310-n, and n≥1 are natural numbers of the first horizontal transport layers 210-1 to 210-n, and n≥1 shown in FIGS. 2 and 3. May be the same as the composition and thickness.

That is, the electron blocking layer 125-2 may include the first horizontal transport layers 210-1 to 210-n of the electron blocking layer 125-1, a natural number of n≥1, and the first vertical transport layer ( The second horizontal transport layer 310-1 to 310-n and a natural number of n ≧ 1) may be interposed between 220-1 to 220-n and a natural number of n≥1.

A two-dimensional hole gas region 10 is formed in the first horizontal transport layers 210-1 to 210-n, and n≥1, and a natural number of second horizontal transport layers 310-1 to 310-n, and n≥1. ) May be formed with a two-dimensional hole gas region 20. Compared with the first embodiment, since the holes are more easily dispersed in the horizontal direction 102 by the two-dimensional hole gas regions 10 and 20, the luminous efficiency may be further improved.

FIG. 6 shows a third embodiment 125-3 of the electron blocking layer 125 shown in FIG. 1, and FIG. 7 shows an energy band diagram of the electron blocking layer 125-3 shown in FIG. The same reference numerals as those of Fig. 2 and Fig. 3 denote the same configuration, and the content overlapping with the above description will be omitted or briefly described.

6 and 7, the current diffusion layers 401-1 to 401-n, and natural numbers of n≥1, may include a first horizontal transport layer 210-1 to 210-n, natural numbers of n≥1, and a first vertical direction. And transport layers 220-1 to 220-n (natural numbers of n ≧ 1) and second vertical transport layers (410-1 to 410-n, natural numbers of n ≧ 1).

The composition and thickness of the second vertical transport layers 410-1 to 410-n, and n≥1 are natural numbers of the first vertical transport layers 220-1 to 220-n, and n≥1 shown in FIGS. 2 and 3. May be the same as the composition and thickness.

That is, the electron blocking layer 125-3 further includes a second vertical transport layer 410-1 to 410-n, a natural number of n≥1, in addition to the electron blocking layer 125-1 according to the first embodiment. It can have

The composition of the second vertical transport layers 410-1 to 410-n, a natural number of n ≧ 1, may be Al _z Ga _(1-z) N (0 < _z ≦ 0.22), and the content of aluminum (Al) (z ) May decrease linearly or nonlinearly.

The maximum value z _max of the aluminum content z of the second vertical transport layers 410-1 to 410-n, a natural number of n≥1, is equal to the first vertical transport layers 220-1 to 220-n, n≥1. May be less than or equal to the maximum value y _max of the aluminum content y of the natural number) (z _max ≦ y _max ). As a result, in comparison with the first and second embodiments, the electron blocking layer 125-3 of the third embodiment may have a barrier having a more gentle slope in terms of movement of holes in the vertical direction.

The thickness of the second vertical transport layers 410-1 to 410-n, a natural number of n ≧ 1, may be 5 nm or less. The thickness of the second vertical transport layers 410-1 to 410-n, a natural number of n≥1 may be the same as the thickness of the third layers 216-1 to 216-n, a natural number of n≥1, but is not limited thereto. It doesn't happen.

Compared with the first and second embodiments, since the third embodiment has a barrier having a gentler slope, the hole can be moved more easily in the vertical direction 101, thereby improving the hole injection efficiency. It is possible to further improve the luminous efficiency and to further reduce the operating voltage.

8 illustrates a light emitting device 200 according to another embodiment. Referring to FIG. 8, the light emitting device 200 includes a second electrode layer 405, a protective layer 430, a light emitting structure 120, a passivation layer 440, and a first electrode 450.

The second electrode layer 405 together with the first electrode 450 provides power to the light emitting structure 120. The second electrode layer 405 may include a support substrate 422, a bonding layer 424, a barrier layer 426, a reflective layer 428, and an ohmic layer 429.

The support substrate 422 supports the light emitting structure 120 and may be formed of a conductive material. For example, the support substrate 422 may include copper (Cu), gold (Au), nickel (Ni), molybdenum (Mo), copper-tungsten (Cu-W), carrier wafers (eg, Si, Ge, GaAs, ZnO, SiC) may be included.

The barrier layer 426 is disposed on the support substrate 422, and prevents metal ions of the support substrate 110 from diffusing into the reflective layer 428 and the ohmic layer 429. For example, the barrier layer 426 includes at least one of Ni, Pt, Ti, W, V, Fe, and Mo, and may be a single layer or a multilayer.

The bonding layer 424 is disposed between the support substrate 422 and the barrier layer 426. The bonding layer 424 is a bonding layer, which allows the reflective layer 428 and the ohmic layer 429 to be bonded to the supporting substrate 422. The bonding layer 424 may include at least one of a bonding metal, for example, Ti, Au, Sn, Ni, Cr, Ga, In, Bi, Cu, Ag, or Ta.

Reflective layer 428 is disposed on barrier layer 426. The reflective layer 428 may reflect light incident from the light emitting structure 120, thereby improving light extraction efficiency. The reflective layer 428 may be formed of a metal or an alloy including a reflective material, for example, at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf. In addition, the reflective layer 428 may be formed in a multilayer using a metal or an alloy and a transparent conductive material such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, or ATO. For example, the reflective layer 428 may be formed of IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni, or the like.

The ohmic layer 429 is disposed on the reflective layer 428. The ohmic layer 429 is in ohmic contact with the second conductive semiconductor layer 126 of the light emitting structure 120 to smoothly supply power to the light emitting structure 120. The ohmic layer 429 may selectively use a light transmissive conductive layer and a metal. For example, the ohmic layer 429 may include indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), and indium gallium (IGTO). tin oxide), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrO _x , RuO _x , RuO _x / ITO, Ni, Ag, Ni / IrO _x / Au, and Ni / One or more of IrO _x / Au / ITO can be used to implement a single layer or multiple layers.

The protective layer 430 is disposed on the second electrode layer 405. The protective layer 430 may reduce a phenomenon in which the interface between the light emitting structure 120 and the barrier layer 426 is peeled off, thereby reducing the reliability of the light emitting device 200. The protective layer 430 may be a conductive material or a non-conductive material. For example, the conductive protective layer may be formed of a transparent conductive oxide film or may include at least one of a metal material such as Ti, Ni, Pt, Pd, Rh, Ir, and W. In addition, the non-conductive protective layer may be formed of a material having a lower electrical conductivity than the reflective layer 428 or the ohmic layer 429, a material forming Schottky contact with the second conductive semiconductor layer 126, or an electrically insulating material. have. For example, the nonconductive protective layer may be formed of ZnO or SiO ₂ .

The light emitting structure 120 is disposed on the second electrode layer 405. The light emitting structure 120 may include a first conductivity type semiconductor layer 122, an active layer 124, an electron blocking layer 125, and a second conductivity type semiconductor layer 126, as described with reference to FIG. 1. can do. The electron blocking layer 125 may be any one of the first to third embodiments. In order to avoid duplication, a description of the light emitting structure 120 will be omitted.

The passivation layer 440 may be formed on the side of the light emitting structure 120 to electrically protect the light emitting structure 120, but is not limited thereto. The passivation layer 440 may be formed of an insulating material such as SiO ₂ , SiO _x , SiO _x N _y , Si ₃ N ₄ , to be formed of Al ₂ O ₃ Can be. Roughness (not shown) may be formed on the top surface of the first conductive semiconductor layer 122 to increase light extraction efficiency. The first electrode 450 is disposed on the upper surface of the light emitting structure 120.

As described above, the embodiment illustrated in FIG. 8 may improve the luminous efficiency and reduce the operating voltage by the electron blocking layers 125-1 to 125-3 according to the first to third embodiments.

9 illustrates a light emitting device package according to an embodiment. 9, the light emitting device package may include a package body 510, a first metal layer 512, a second metal layer 514, a light emitting device 520, a reflector 530, a wire 530, and a resin layer ( 540).

The package body 510 is a structure in which a cavity consisting of side and bottom is formed in one region. At this time, the side wall of the cavity may be formed to be inclined. The package body 510 may be formed of a substrate having good insulation or thermal conductivity, such as a silicon-based wafer level package, a silicon substrate, silicon carbide (SiC), aluminum nitride (AlN), or the like. It may have a structure in which a plurality of substrates are stacked. The embodiments are not limited to the material, structure, and shape of the body described above.

The first metal layer 512 and the second metal layer 514 are disposed on the surface of the package body 510 to be electrically separated from each other in consideration of heat dissipation or mounting of a light emitting device. The light emitting device 520 is electrically connected to the first metal layer 512 and the second metal layer 514. In this case, the light emitting device 520 may be any one of the embodiments 100 or 200.

The reflective plate 530 is formed on the side wall of the cavity of the package body 510 to direct light emitted from the light emitting element 520 in a predetermined direction. The reflector plate 530 is made of a light reflective material, and may be, for example, a metal coating or a metal flake.

The resin layer 540 surrounds the light emitting device 520 positioned in the cavity of the package body 510 to protect the light emitting device 520 from the external environment. The resin layer 540 is made of a colorless transparent polymer resin material such as epoxy or silicon. The resin layer 540 may include a phosphor to change the wavelength of light emitted from the light emitting device 520. The light emitting device package may include at least one of the feet and the devices according to the exemplary embodiment disclosed above, but is not limited thereto.

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

Still another embodiment may be implemented as a display device, an indicating device, and a lighting system including the light emitting device or the light emitting device package described in the above embodiments. For example, the lighting system may include a lamp and a streetlight.

10 is an exploded perspective view of a lighting device including a light emitting device package according to an embodiment. Referring to FIG. 10, the lighting apparatus according to the embodiment includes a light source 750 for projecting light, a housing 700 in which the light source 750 is built, a heat dissipation unit 740 for dissipating heat from the light source 750, and a light source. The holder 760 couples the 750 and the heat dissipation part 740 to the housing 700.

The housing 700 includes a socket coupling portion 710 coupled to an electric socket (not shown), and a body portion 730 connected to the socket coupling portion 710 and having a light source 750 embedded therein. One air flow hole 720 may be formed through the body portion 730.

A plurality of air flow holes 720 are provided on the body portion 730 of the housing 700 and one or more air flow holes 720 may be provided. The air flow port 720 may be disposed radially or in various forms on the body portion 730.

The light source 750 includes a plurality of light emitting device packages 752 provided on the substrate 754. [ The substrate 754 may have a shape that can be inserted into the opening of the housing 700 and may be made of a material having a high thermal conductivity to transmit heat to the heat dissipating unit 740 as described later. The plurality of light emitting device packages may be the above-described embodiments.

A holder 760 is provided below the light source 750, and the holder 760 may include a frame and other air flow holes. Although not shown, an optical member may be provided under the light source 750 to diffuse, scatter, or converge light projected from the light emitting device package 752 of the light source 750.

11 illustrates a display device including a light emitting device package according to an exemplary embodiment. Referring to FIG. 11, the display device 800 includes a bottom cover 810, a reflector 820 disposed on the bottom cover 810, light emitting modules 830 and 835 that emit light, and a reflector 820. ) An optical sheet including a light guide plate 840 which is disposed in front of the light guide plate and guides light emitted from the light emitting modules 830 and 835 to the front of the display device, and prism sheets 850 and 860 disposed in front of the light guide plate 840. And a display panel 870 disposed in front of the optical sheet, an image signal output circuit 872 connected to the display panel 870 and supplying an image signal to the display panel 870, and in front of the display panel 870. It may include a color filter 880 disposed. Here, the bottom cover 810, the reflection plate 820, the light emitting modules 830 and 835, the light guide plate 840, and the optical sheet may form a backlight unit.

The light emitting module comprises a light emitting device package 835 on a substrate 830. The substrate 830 may be a PCB or the like. The light emitting device package 835 may be a light emitting device package according to an embodiment.

The bottom cover 810 can house components within the display device 800. [ Also, the reflection plate 820 may be formed as a separate component as shown in the drawing, or may be provided on the rear surface of the light guide plate 840 or on the front surface of the bottom cover 810 in a state of being coated with a highly reflective material .

Here, the reflection plate 820 can be made of a material having a high reflectance and can be used in an ultra-thin shape, and polyethylene terephthalate (PET) can be used.

The light guide plate 830 may be formed of polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene (PE), or the like.

The first prism sheet 850 may be formed of a light-transmissive and elastic polymeric material on one side of the support film, and the polymer may have a prism layer in which a plurality of three-dimensional structures are repeatedly formed. Here, as shown in the drawings, the plurality of patterns may be provided with a floor and a valley repeatedly as stripes.

In the second prism sheet 860, the direction of the floor and the valley on one side of the supporting film may be perpendicular to the direction of the floor and the valley on one side of the supporting film in the first prism sheet 850. This is for evenly distributing the light transmitted from the light emitting module and the reflective sheet to the front surface of the display panel 1870.

Although not shown, a diffusion sheet may be disposed between the light guide plate 840 and the first prism sheet 850. The diffusion sheet may be made of polyester and polycarbonate-based materials, and the light incidence angle can be maximized by refracting and scattering light incident from the backlight unit. The diffusion sheet includes a support layer including a light diffusing agent, a first layer formed on the light exit surface (first prism sheet direction) and a light incidence surface (in the direction of the reflection sheet) . &Lt; / RTI &gt;

In an embodiment, the diffusion sheet, the first prism sheet 850, and the second prism sheet 1860 form an optical sheet, which optical sheet is made of another combination, for example, a micro lens array or a diffusion sheet and a micro lens array. Or a combination of one prism sheet and a micro lens array.

The display panel 870 may include a liquid crystal display (LCD) panel, and may include other types of display devices that require a light source in addition to the liquid crystal display panel 860.

In addition, the above description has been made with reference to the embodiments, which are merely exemplary and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains will be illustrated above in the range without departing from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are possible.

110,420: substrate 120: light emitting structure
122: first conductivity type semiconductor layer 124: active layer
125: electron blocking layer 126: second conductivity type semiconductor layer
130: conductive layer 142, 450: first electrode
144: second electrode 210-1 to 210-n: first horizontal transport layer
212-1 to 212-n: first layer 214-1 to 214-n: second layer
216-1 to 216-n: third layer 220-1 to 220-n: first vertical transport layer
310-1 to 310-n: second horizontal transport layer 410-1 to 410-n: second vertical transport layer
405: second electrode layer 422: support substrate
424: bonding layer 426: barrier layer
428: reflective layer 429: ohmic layer
430: protective layer 440: passivation layer
QW1 to QW3: quantum well layers QB1 to QB2: quantum barrier layers.

Claims (16)

A first conductive semiconductor layer;
A second conductivity type semiconductor layer disposed on the first conductivity type semiconductor layer;
An active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer; And
An electron blocking layer disposed between the active layer and the second conductive semiconductor layer,
Wherein the electron blocking layer
At least one first horizontal transport layer,
The at least one first horizontal transport layer,
A first layer having a composition of AlN;
A second layer having a composition of GaN; And
A light emitting device comprising a third layer having a composition of Al _x Ga _(1-x) N (0 <x <1). The method of claim 1,
The first layer is located between the active layer and the second conductivity type semiconductor layer, the second layer is located between the first layer and the second conductivity type semiconductor layer, and the third layer is located between the second layer and the second layer. A light emitting device positioned between the second conductive semiconductor layer. The method of claim 1,
The at least one first horizontal transport layer is a light emitting device having a superlattice structure. The method of claim 1,
The composition of the third layer is Al _x Ga _(1-x) N (0 <x≤0.22), and the content (x) of aluminum in the third layer is from the first conductivity type semiconductor layer to the second conductivity type. A light emitting device that increases in the direction of the semiconductor layer. The method of claim 1,
The second layer is an undoped layer. The method of claim 1,
The third layer is a light emitting device doped with a p-type dopant. The method of claim 1, wherein the electron blocking layer,
Located between the third layer and the second conductivity-type semiconductor layer, has a composition of Al _y Ga _(1-y) N (0 <y <1), the content (y) of aluminum (Al) is the first conductive The light emitting device of claim 1, further comprising a first vertical transport layer that decreases from the semiconductor semiconductor layer toward the second conductive semiconductor layer. The method of claim 7, wherein
The composition of the first vertical transport layer is Al _y Ga _(1-y) N (0 <y≤0.22). The method of claim 8, wherein the electron blocking layer,
A fourth layer disposed between the first horizontal transport layer and the first vertical transport layer and having a composition of AlN;
A fifth layer located between the fourth layer and the first vertical transport layer and having a composition of GaN; And
And a second vertical transport layer disposed between the fifth layer and the first vertical transport layer, the second vertical transport layer comprising a sixth layer having a composition of Al _a Ga _(1-a) N (0 <a ≦ 0.22). 10. The method of claim 9,
The content (x) of aluminum in the sixth layer increases as the direction progresses from the first conductive semiconductor layer toward the second conductive semiconductor layer. 10. The method of claim 9,
And the fifth layer is an undoped layer, and the sixth layer is doped with a p-type dopant. The method of claim 7, wherein the electron blocking layer,
Located between the first vertical transport layer and the second conductivity-type semiconductor layer, has a composition of Al _y Ga _(1-z) N (0 <z <1), the content (z) of aluminum (Al) is The light emitting device further comprising a second vertical transport layer that decreases from the conductive semiconductor layer toward the second conductive semiconductor layer. The method of claim 12,
The composition of the second vertical transport layer is Al _z Ga _(1-z) N (0 < _z ≤ 0.22). The method of claim 12,
The maximum value of the aluminum content (z) of the second vertical transport layer is less than or equal to the maximum value of the aluminum content (y) of the first vertical transport layer. 15. The method according to any one of claims 1 to 14,
A substrate disposed under the first conductive semiconductor layer;
A conductive layer disposed on the second conductive semiconductor layer;
A first electrode disposed on the first conductive semiconductor layer; And
And a second electrode disposed on the conductive layer. 15. The method according to any one of claims 1 to 14,
An ohmic layer disposed under the second conductive semiconductor layer;
A reflective layer disposed below the ohmic layer; And
The light emitting device further comprising a first electrode disposed on the first conductive semiconductor layer.

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