WO2016003049A1

WO2016003049A1 - Light emitting element and lighting system including same

Info

Publication number: WO2016003049A1
Application number: PCT/KR2015/002544
Authority: WO
Inventors: 최광용; 장정훈
Original assignee: 엘지이노텍 주식회사
Priority date: 2014-06-30
Filing date: 2015-03-17
Publication date: 2016-01-07
Also published as: KR20160001951A; KR102261948B1

Abstract

A light emitting element according to an embodiment comprises: a substrate; a first buffer layer disposed on the substrate; a second buffer layer that is disposed on the first buffer layer and contains Al; a first conductive type semiconductor layer disposed on the second buffer layer; an active layer disposed on the first conductive type semiconductor layer; and a second conductive type semiconductor layer disposed on the active layer, wherein the second buffer layer includes a first layer and a second layer that are horizontally arranged, in which case the first layer has a gradually increasing Al ratio toward the first conductive type semiconductor layer, and the second layer has a gradually decreasing Al ratio toward the first conductive type semiconductor layer. In the embodiment, the first layer that has a linearly increasing Al ratio and the second layer that has a linearly decreasing Al ratio are horizontally arranged in the buffer layer, which makes it possible to effectively control strain caused by lattice mismatch and a difference in a coefficient of thermal expansion between the substrate and the first conductive type semiconductor layer.

Description

Light emitting device and lighting system having same

The embodiment relates to a light emitting device for improving light efficiency.

In general, a light emitting device is a compound semiconductor having a characteristic in which electrical energy is converted into light energy. The light emitting device may be formed of compound semiconductors such as group III and group V on the periodic table, and various colors may be adjusted by adjusting the composition ratio of the compound semiconductor. Implementation is possible.

When the forward voltage is applied, the n-layer electrons and the p-layer holes combine to emit energy corresponding to the bandgap energy of the conduction band and the valence band. Is mainly emitted in the form of heat or light, and emits light in the form of light emitting elements. For example, nitride semiconductors are receiving great attention in the field of optical devices and high power electronic devices due to their high thermal stability and wide bandgap energy. In particular, blue light emitting devices, green light emitting devices, and ultraviolet light emitting devices using nitride semiconductors are commercially used and widely used.

Conventional nitride semiconductors are formed by sequentially stacking a first conductive semiconductor layer of GaN material, an active layer and a second conductive semiconductor layer on a substrate, and smoothly flow holes between the active layer and the second conductive semiconductor layer. A hole injection layer for forming is formed.

Although the hole injection layer is mainly formed of a single layer doped with Mg, a problem occurs in that the output Po and the light efficiency measurement voltage VF1 fall in the long wavelength region.

In order to solve the above problems, an embodiment is to provide a light emitting device for improving the light efficiency and an illumination system having the same.

In order to achieve the above object, a light emitting device according to an embodiment includes a substrate, a first conductive semiconductor layer disposed on the substrate, an active layer disposed on the first conductive semiconductor layer, and on the active layer A second conductive semiconductor layer disposed, a first hole injection layer disposed between the active layer and the second conductive semiconductor layer and undoped, and a second doped p-type dopant disposed on the first hole injection layer It may include a hole injection layer including a hole injection layer.

The embodiment has the effect of improving the output voltage and the light efficiency measurement voltage while maintaining the operating voltage by forming a layer in which the p-type dopant is removed in the hole injection layer.

In addition, in the embodiment, the hole injection layer is formed so that the first hole injection layer and the second hole injection layer are paired, thereby reducing the lattice mismatch of the upper and lower layers.

In addition, the embodiment further includes an InN layer in the hole injection layer, thereby preventing the p-type dopant from diffusing into the active layer.

In addition, the embodiment further improves the hole injection efficiency by further disposing a GaN layer having a lower p-type dopant concentration of the lowermost layer of the hole injection layer.

1 is a cross-sectional view of a light emitting device according to a first embodiment.

2 is a cross-sectional view illustrating a hole injection layer of the light emitting device according to the first embodiment.

3 to 6 are graphs showing the Mg doping method of the hole injection layer according to the first embodiment.

7 is a graph showing Po of the light emitting device according to the first embodiment.

8 is a graph illustrating VF1 of the light emitting device according to the first embodiment.

9 is a graph showing VF3 of the light emitting device according to the first embodiment.

10 is a sectional view showing a light emitting device according to the second embodiment.

11 is a cross-sectional view illustrating a hole injection layer of a light emitting device according to a second embodiment.

12 is a sectional view showing a light emitting device according to the third embodiment.

13 and 14 are cross-sectional views illustrating a hole injection layer of the light emitting device according to the third embodiment.

15 is a sectional view showing a light emitting device according to the fourth embodiment.

16 is a cross-sectional view illustrating a hole injection layer of a light emitting device according to a fourth embodiment.

17 is a cross-sectional view illustrating a package of a light emitting device with a light emitting device according to embodiments.

18 to 20 are exploded perspective views showing embodiments of a lighting system having a light emitting device according to the embodiments.

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

1 is a cross-sectional view illustrating a light emitting device according to a first embodiment, FIG. 2 is a cross-sectional view showing a hole injection layer of a light emitting device according to a first embodiment, and FIGS. 3 to 6 are hole injections according to a first embodiment. FIG. 7 is a graph showing Po of the light emitting device according to the first embodiment, FIG. 8 is a graph showing VF1 of the light emitting device according to the first embodiment, and FIG. A graph showing VF3 of the light emitting device according to the embodiment.

1 and 2, the light emitting device according to the first embodiment includes a substrate 110, a buffer layer 181 disposed on the substrate, and a strain control layer 183 disposed on the buffer layer 181. ), A first conductive semiconductor layer 120 disposed on the strain control layer 183, a current spreading layer 185 disposed on the first conductive semiconductor layer 120, and the current spreading layer ( The active layer 130 disposed on the active layer 130, the hole injection layer 140 disposed on the active layer 130, the electron blocking layer 187 disposed on the hole injection layer 140, and the electrons. The second conductive semiconductor layer 150 disposed on the blocking layer 187, the light transmissive electrode layer 189 disposed on the second conductive semiconductor layer 150, and the first conductive semiconductor layer 120. The first electrode 160 is disposed on the first electrode 160, and the second electrode 170 is disposed on the transparent electrode layer 189.

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 use at least one of sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, and Ga ₂ 0 ₃ .

A buffer layer 181 may be disposed on the substrate 110. The buffer layer 181 serves to alleviate the lattice mismatch between the material of the light emitting structure and the substrate 110. The buffer layer 181 may include a group III-V compound semiconductor. The buffer layer 181 may be formed of a material including Al. The buffer layer 120 may be formed of at least one of AlN, AlGaN, InAlGaN, and AlInN. A strain control layer 183 may be disposed on the buffer layer 181.

The first conductivity type semiconductor layer 120 may be disposed on the strain control layer 183.

The first conductivity-type semiconductor layer 120 may include, for example, an n-type semiconductor layer. The first conductivity type semiconductor layer 120 may be implemented as a compound semiconductor. The first conductivity type semiconductor layer 120 may be implemented as, for example, a group II-VI compound semiconductor or a group III-V compound semiconductor.

The first conductivity type semiconductor layer 120 is formed of a semiconductor material having a composition formula of In _x Al _y Ga ₁ _-x- _y N (0≤x≤1, 0≤y≤1, 0≤x + y≤1). Can be. The first conductivity type semiconductor layer 120 may be selected from, for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP, and the like. N-type dopants such as Se and Te may be doped.

The current diffusion layer 185 may be disposed on the first conductivity type semiconductor layer 120.

The current diffusion layer 185 may increase light efficiency by improving internal quantum efficiency, and may be an undoped gallium nitride layer. An electron injection layer (not shown) may be further formed on the current diffusion layer 185. The electron injection layer may be a conductive gallium nitride layer. For example, in the electron injection layer, the n-type doping element is doped at a concentration of 6.0x10 ¹⁸ atoms / cm ³ to 3.0x10 ¹⁹ atoms / cm ³ , thereby enabling efficient electron injection.

The active layer 130 may be disposed on the current spreading layer 185.

In the active layer 130, electrons (or holes) injected through the first conductive semiconductor layer 120 and holes (or electrons) injected through the second conductive semiconductor layer 150 meet each other, and thus, the active layer is formed. The layer emits light due to a band gap difference of an energy band according to the forming material of 130. The active layer 130 may be formed of any one of a single well structure, a multiple well structure, a quantum dot structure, or a quantum line structure, but is not limited thereto.

The active layer 130 may be implemented with a compound semiconductor. The active layer 130 may be implemented as, for example, a group II-VI or group III-V compound semiconductor. The active layer 130 may be formed of, for example, a semiconductor material having a composition formula of In _x Al _y Ga ₁ _-x- _y N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1). have. When the active layer 130 is implemented as the multi-well structure, the active layer 130 may be implemented by stacking a plurality of well layers and a plurality of barrier layers, for example, an InGaN well layer / GaN barrier layer. Can be implemented in cycles.

The hole injection layer 140 may be disposed on the active layer 130.

The hole injection layer 140 may increase the light emission efficiency by effectively moving holes to the center of the light emitting layer. The hole injection layer 140 may include a first hole injection layer 141 and a second hole injection layer 143. The first hole injection layer 141 may be an undoped layer. The second hole injection layer 143 may be a layer doped with a p-type dopant. The hole injection layer 140 will be described in detail later with reference to the drawings.

An electron blocking layer EBL 187 may be disposed on the hole injection layer 140.

The electron blocking layer 187 serves as electron blocking and cladding of the active layer, thereby improving luminous efficiency. The electron blocking layer 187 may be formed of an Al _x In _y Ga _(1-xy) N (0 ≦ _x ≦ 1,0 ≦ _y ≦ 1) based semiconductor, and may be higher than the energy band gap of the active layer 130. It may have an energy band gap, and may be formed to a thickness of about 100 kPa to about 600 kPa, but is not limited thereto. Alternatively, the electron blocking layer 187 may be formed of Al _z Ga _(1-z) N / GaN (0 ≦ z ≦ 1) superlattice.

The second conductivity type semiconductor layer 150 may be disposed on the electron blocking layer 187.

The second conductivity-type semiconductor layer 150 may be implemented with, for example, a p-type semiconductor layer. The second conductivity-type semiconductor layer 150 may be implemented as a compound semiconductor. For example, the second conductivity-type semiconductor layer 150 may be implemented as a group II-VI compound semiconductor or a group III-V compound semiconductor.

The second conductive type semiconductor layer 150 is a semiconductor material having a compositional formula of _{_{_{_{_{In x Al y Ga 1 -x- y}}}}} N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) Can be implemented. The second conductive semiconductor layer 150 may be selected from, for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP, and the like, and may include Mg, Zn, Ca, P-type dopants such as Sr and Be may be doped.

The first conductive semiconductor layer 120 may include a p-type semiconductor layer, and the second conductive semiconductor layer 150 may include an n-type semiconductor layer. In addition, a semiconductor layer including an n-type or p-type semiconductor layer may be further formed below the second conductive semiconductor layer 150. Accordingly, the light emitting structure may have at least one of np, pn, npn, and pnp junction structures.

Doping concentrations of impurities in the first conductive semiconductor layer 120 and the second conductive semiconductor layer 150 may be uniformly or non-uniformly formed. That is, the structure of the light emitting structure may be formed in various ways, but is not limited thereto.

The light transmissive electrode layer 189 may be disposed on the second conductive semiconductor layer 150.

The translucent electrode layer 189 may stack a single metal, a metal alloy, a metal oxide, or the like in multiple layers so as to efficiently inject carriers. For example, the light transmissive electrode layer 189 may be formed of a material having excellent electrical contact with a semiconductor. The light transmissive electrode layer 189 may be indium tin oxide (ITO), indium zinc oxide (IZO), or indium zinc tin oxide (IZTO). , Indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IZO Nitride ), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), ZnO, IrOx, RuOx, NiO, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO, Ag, Ni, Cr , Ti, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf may be formed including at least one, and is not limited to these materials.

The second electrode 170 is formed on the light transmissive electrode layer 189, and the first electrode 160 is formed on the first conductive semiconductor layer 120 having a portion of the upper portion exposed. As the first electrode 160 and the second electrode 170, for example, Cr, Ti, Ag, Ni, RH, Pd, Ir, Ru, Mg, Zn, Pt, Cu, Au. It may be formed of a metal or an alloy containing any one of Hf. Thereafter, the first electrode 160 and the second electrode 170 are finally connected to each other, thereby manufacturing the light emitting device.

As shown in FIG. 2, the hole injection layer 140 according to the first embodiment may include a first hole injection layer 141 and a second hole injection layer 143.

A first hole injection layer 141 can be a layer of undoped _{_{_{_{_{In x Al y Ga 1 -x- y}}}}} N (0 <x≤1, 0 <y≤1, 0 <x + y≤1). The second hole injection layer 143 can be a layer of p-type dopant of _{_{_{_{_{In x Al y Ga 1 -x- y}}}}} N (0 <x≤1, 0 <y≤1, 0 <x + y≤1) doped . The p-type dopant may include Mg, Zn, Ca, Sr, Be. The composition of Al in the first hole injection layer 141 and the second hole injection layer 143 may be 25% to 35%, and more specifically, 30%. When the composition of Al is 25% or less or 35% or more, the output voltage Po decreases.

For example, the total thickness T11 of the hole injection layer 140, for example, the first hole injection layer 141 and the second hole injection layer 143, may be 15 μm to 25 μm, and more specifically, 20 μm to be formed. Can be. The thickness T12 of the first hole injection layer 141 may be smaller than the thickness T13 of the second hole injection layer 143. Alternatively, the thickness T12 of the first hole injection layer 141 may be the same as the thickness T13 of the second hole injection layer 143. The ratio of the thickness T12 of the first hole injection layer 141 and the thickness T13 of the second hole injection layer 143 may be 1: 1 to 1: 3.

When the thickness T13 of the second hole injection layer 143 is formed to be thinner than the thickness T12 of the first hole injection layer 141, the concentration of the p-type dopant is decreased, so that the output voltage Po in the long wavelength region is obtained. Although the light efficiency measuring voltage VF1 has an improvement effect, a problem arises in that the operating voltage VF3 becomes high. Therefore, when the ratio of the thickness T12 of the first hole injection layer 141 and the thickness T13 of the second hole injection layer 143 is 1: 1, as shown in Table 1, in the long wavelength region, The output voltage Po and the light efficiency measurement voltage VF1 may obtain an improvement effect, from which the thickness T12 of the first hole injection layer 141 and the thickness T13 of the second hole injection layer 143 may be obtained. When the ratio is 1: 1 to 1: 3, the improvement effect of the output voltage Po and the light efficiency measurement voltage VF1 may be maximized.

Table 1

Run Information			Low current	characteristic
NO	Purpose	Epi structure	Ir Vr Vf1 Vf2-5V -10uV 0.1uV 0.1uV	Vf3 Po350mA 350mA
One	Dual Peak LED	Repeat S0738	0.002 20.7 1.94 2.1587% 66% 93% 94%	2.97 493.099% 78%
2	2step pQ test	Based on S0876	0.002 20.7 1.88 2.0992% 79% 86% 89%	3.00 438.9 100% 69%
Run Information			yield	wavelength
NO	Purpose	Epi structure	Target SCR Recognition Good Good Good Good Reject after Prober initial SCR	Wd Wp350mA 350mA
One	Dual Peak LED	Repeat S0738	466 301 235 68 66 100% 65% 50% 15% 14%	443.6 438.822% 97%
2	2step pQ test	Based on S0876	435 334 287 253 47 100% 77% 66% 58% 11%	448.5 445.384% 100%

The p-type dopant of the second hole injection layer 143, for example, the concentration of Mg may be 1E18 to 3E20. As described above, the concentration of Mg is a concentration value for optimizing the output voltage Po and the light efficiency measurement voltage VF1 in the long wavelength region.

The p-type dopant may be formed to have a uniform concentration value along the thickness direction of the second hole injection layer 143.

As shown in FIG. 3, the p-type dopant may be supplied at a uniform concentration in the thickness direction of the second hole injection layer 143. For example, the p-type dopant may be continuously supplied to the second hole injection layer 143 while the target concentration value Ta, that is, 1E18 to 3E20 is maintained.

Alternatively, as shown in FIG. 4, the p-type dopant may be supplied at a uniform concentration in the thickness direction of the second hole injection layer 143, and the p-type dopant may be repeatedly supplied at a predetermined time.

The p-type dopant may be formed to increase the concentration value along the thickness direction of the second hole injection layer 143.

As shown in FIG. 5, the p-type dopant may be supplied while sequentially increasing the concentration in the thickness direction of the second hole injection layer 143. Here, the p-type dopant may be supplied at a concentration value Tb higher than the target target concentration value Ta to adjust the p-type dopant concentration value of the second hole injection layer 143 to 1E18 to 3E20.

Alternatively, as shown in FIG. 6, the p-type dopant is supplied while increasing the concentration in the thickness direction of the second hole injection layer 143 sequentially, and the p-type dopant may be repeatedly supplied at a predetermined time.

As shown in FIG. 7, when the output voltage Po between the hole injection layer 140 and the conventional hole injection layer R according to the embodiment is described, the hole injection layer structure according to the embodiment has a long wavelength region ( As shown to A), it can be seen that the output voltage Po is improved compared to the conventional hole injection layer R structure. For example, it can be seen that the hole injection layer 140 structure according to the embodiment is increased by about 20 mW by 4% on average.

As shown in FIG. 8, when looking at the light efficiency voltage VF1 of the hole injection layer 140 and the conventional hole injection layer R according to the embodiment, the structure of the hole injection layer 140 according to the embodiment It can be seen that toward the long wavelength region A, the light efficiency voltage VF1 is improved.

As shown in FIG. 9, the hole injection layer 140 according to the embodiment includes the second hole injection layer including the p-type dopant even if the first hole injection layer from which the p-type dopant is removed exists, thereby operating voltage. It can be seen that (VF3) was kept stable.

As shown in FIGS. 7 to 9, the hole injection layer 140 of the two-layer structure according to the embodiment improves the output voltage Po and the light efficiency measurement voltage VF1 while maintaining the operating voltage VF3. It can be seen that there is an effect of improving the efficiency.

10 is a sectional view showing a light emitting device according to the second embodiment, and FIG. 11 is a sectional view showing a hole injection layer of the light emitting device according to the second embodiment.

Referring to FIG. 10, the light emitting device according to the second embodiment includes a substrate 210, a buffer layer 281 disposed on the substrate 210, and a strain control layer 283 disposed on the buffer layer 281. ), A first conductive semiconductor layer 220 disposed on the strain control layer 283, a current spreading layer 285 disposed on the first conductive semiconductor layer 220, and the current spreading layer ( The active layer 230 disposed on the 285, the hole injection layer 240 disposed on the active layer 230, the electron blocking layer 287 disposed on the hole injection layer 240, and the electrons. The second conductive semiconductor layer 250 disposed on the blocking layer 287, the transmissive electrode layer 289 disposed on the second conductive semiconductor layer 250, and the first conductive semiconductor layer 220. The first electrode 260 is disposed on the second electrode 260, and the second electrode 270 is disposed on the transparent electrode layer 289. Here, the configuration except for the hole injection layer 240 is the same as the configuration of the light emitting device according to the first embodiment and thus will be omitted.

As illustrated in FIG. 11, the hole injection layer 240 may include a first hole injection layer 241, a second hole injection layer 243, a third hole injection layer 245, and a fourth hole injection layer 247. It may include. The first hole injection layer 241 and the third hole injection layer 245 may be undoped InAlGaN layer. The second hole injection layer 243 and the fourth hole injection layer 247 may be an InAlGaN layer doped with a p-type dopant.

The thickness T21 of the hole injection layer 240 may be 15 mm to 25 mm. The thickness of the first hole injection layer 241 may be the same as the thickness of the third hole injection layer 245. The thickness of the second hole injection layer 243 may be the same as the thickness of the fourth hole injection layer 247. The ratio of the thicknesses of the first hole injection layer 241 and the second hole injection layer 243 may be 1: 1 to 1: 3. Correspondingly, the ratio of the thicknesses of the third hole injection layer 245 and the fourth hole injection layer 247 may be 1: 1 to 1: 3.

The p-type dopant of the second hole injection layer 243 and the fourth hole injection layer 247, for example, the concentration of Mg may be 1E18 to 3E20.

As described above, in the light emitting device according to the second embodiment, a plurality of hole injection layers 240 are formed such that the first hole injection layer and the second hole injection layer are paired, thereby alleviating the lattice mismatch between the layers. It has an effect.

12 is a cross-sectional view illustrating a light emitting device according to a third embodiment, and FIGS. 13 and 14 are cross-sectional views illustrating a hole injection layer of a light emitting device according to a third embodiment.

Referring to FIG. 12, the light emitting device according to the third embodiment includes a substrate 310, a buffer layer 381 disposed on the substrate 310, and a strain control layer 383 disposed on the buffer layer 381. ), A first conductive semiconductor layer 320 disposed on the strain control layer 383, a current spreading layer 385 disposed on the first conductive semiconductor layer 320, and the current spreading layer ( The active layer 330 disposed on the 385, the hole injection layer 340 disposed on the active layer 330, the electron blocking layer 387 disposed on the hole injection layer 340, and the electrons. The second conductive semiconductor layer 350 disposed on the blocking layer 387, the transparent electrode layer 389 disposed on the second conductive semiconductor layer 350, and the first conductive semiconductor layer 320. The first electrode 360 is disposed on the first electrode 360, and the second electrode 370 is disposed on the light transmissive electrode layer 389. Here, the configuration except for the hole injection layer 340 is the same as the configuration of the light emitting device according to the first embodiment and will be omitted.

As shown in FIG. 13, the hole injection layer 340 includes a first hole injection layer 341 and a second hole injection layer 343 and the first hole injection layer disposed on the first hole injection layer 341. The third hole injection layer 345 may be disposed between the layer 341 and the second hole injection layer 343.

The first hole injection layer 341 may be an undoped InAlGaN layer. The second hole injection layer 343 may be an InAlGaN layer doped with a p-type dopant. The p-type dopant of the second hole injection layer 343, for example, the concentration of Mg may be 1E18 to 3E20.

The third hole injection layer 345 may include InN. The third hole injection layer 345 serves to prevent the p-type dopant included in the second hole injection layer 343 from diffusing into the active layer 330. That is, the third hole injection layer 345 uses In to prevent diffusion of Mg, which is a p-type dopant.

The hole injection layer 340 may have a thickness of 15 mm to 25 mm. The ratio of the thicknesses of the first hole injection layer 341 and the second hole injection layer 343 may be 1: 1 to 1: 3. The thickness of the third hole injection layer 345 may be formed to be 5 Å or less. The sum of the thicknesses of the first hole injection layer 341 and the third hole injection layer 345 is preferably smaller than the thickness of the second hole injection layer 343.

When the sum of the thicknesses of the first hole injection layer 341 and the third hole injection layer 345 is greater than the thickness of the second hole injection layer 343, the concentration of the p-type dopant decreases and the output voltage in the long wavelength region is reduced. Although the Po and the light efficiency measurement voltage VF1 have an improvement effect, a problem arises in that the operating voltage VF3 is increased.

Alternatively, as shown in FIG. 14, the hole injection layer 340 may include the second hole injection layer 343 and the second hole injection layer 343 disposed on the first hole injection layer 341 and the first hole injection layer 341. The first hole injection layer 341 may include a third hole injection layer 345 disposed under the hole injection layer 341.

15 is a cross-sectional view illustrating a light emitting device according to a fourth embodiment, and FIG. 16 is a cross-sectional view illustrating a hole injection layer of a light emitting device according to a fourth embodiment.

Referring to FIG. 15, the light emitting device according to the fourth embodiment includes a substrate 410, a buffer layer 481 disposed on the substrate 410, and a strain control layer 483 disposed on the buffer layer 481. ), A first conductivity type semiconductor layer 420 disposed on the strain control layer 483, a current diffusion layer 485 disposed on the first conductivity type semiconductor layer 420, and the current diffusion layer ( An active layer 430 disposed on the 485, a hole injection layer 440 disposed on the active layer 430, an electron blocking layer 481 disposed on the hole injection layer 440, and the electrons The second conductive semiconductor layer 450 disposed on the blocking layer 481, the transparent electrode layer 489 disposed on the second conductive semiconductor layer 450, and the first conductive semiconductor layer 420. The first electrode 460 is disposed on the second electrode 460, and the second electrode 470 is disposed on the light transmissive electrode layer 489. Here, the configuration except for the hole injection layer 440 is the same as the configuration of the light emitting device according to the first embodiment and thus will be omitted.

As shown in FIG. 16, the hole injection layer 440 includes a first hole injection layer 441 and a second hole injection layer 443 disposed on the first hole injection layer 441, and a first hole injection layer. It may include a third hole injection layer 445 disposed below the layer 441.

The first hole injection layer 441 may be an undoped InAlGaN layer. The second hole injection layer 443 may be an InAlGaN layer doped with a p-type dopant. The p-type dopant of the second hole injection layer 443, for example, the concentration of Mg may be 1E18 to 3E20.

The third hole injection layer 445 may include GaN, InGaN, AlGaN, InAlGaN. The third hole injection layer 445 may include a p-type dopant. The p-type dopant included in the third hole injection layer 445 may have a concentration value of 1/2 or less of the second hole injection layer 443.

The third hole injection layer 445 may improve the output voltage and the light efficiency voltage by minimizing the diffusion of Mg into the active layer 430 by lowering the concentration of the p-type dopant. At the same time, since the third hole injection layer 445 is formed of GaN, InGaN, AlGaN, or InAlGaN, the hole injection efficiency can be further improved.

As shown in FIG. 17, the light emitting device package 500 includes a package body 505, a third electrode layer 513 and a fourth electrode layer 514 disposed on the package body 505, and The light emitting device 100 disposed on the package body 505 and electrically connected to the third electrode layer 513 and the fourth electrode layer 514, and the molding member 530 surrounding the light emitting device 100. Included.

The package body 505 may include a silicon material, a synthetic resin material, or a metal material, and an inclined surface may be formed on a circumference of the light emitting device 100.

The third electrode layer 513 and the fourth electrode layer 514 are electrically separated from each other, and serve to provide power to the light emitting device 100. In addition, the third electrode layer 513 and the fourth electrode layer 514 may serve to increase light efficiency by reflecting the light generated from the light emitting device 100, and generated from the light emitting device 100. It may also serve to release heat to the outside.

The light emitting device 100 may be disposed on the package body 505 or on the third electrode layer 513 or the fourth electrode layer 514.

The light emitting device 100 may be electrically connected to the third electrode layer 513 and / or the fourth electrode layer 514 by any one of a wire method, a flip chip method, or a die bonding method. In the embodiment, the light emitting device 100 is electrically connected to the first electrode layer 513 and the second electrode layer 514 through wires, respectively, but is not limited thereto.

The molding member 530 may surround the light emitting device 100 to protect the light emitting device 100. In addition, the molding member 530 may include a phosphor 532 to change the wavelength of light emitted from the light emitting device 100.

As shown in FIG. 18, the lighting apparatus according to the embodiment includes a cover 2100, a light source module 2200, a heat radiator 2400, a power supply 2600, an inner case 2700, and a socket 2800. It may include. In addition, the lighting apparatus according to the embodiment may further include any one or more of the member 2300 and the holder 2500. The light source module 2200 may include a light emitting device 100 or a light emitting device package 200 according to the present invention.

For example, the cover 2100 may have a shape of a bulb or hemisphere, may be hollow, and may be provided in an open shape. The cover 2100 may be optically coupled to the light source module 2200. For example, the cover 2100 may diffuse, scatter or excite the light provided from the light source module 2200. The cover 2100 may be a kind of optical member. The cover 2100 may be coupled to the heat sink 2400. The cover 2100 may have a coupling part coupled to the heat sink 2400.

An inner surface of the cover 2100 may be coated with a milky paint. The milky paint may include a diffuser to diffuse light. The surface roughness of the inner surface of the cover 2100 may be greater than the surface roughness of the outer surface of the cover 2100. This is for the light from the light source module 2200 to be sufficiently scattered and diffused to be emitted to the outside.

The cover 2100 may be made of glass, plastic, polypropylene (PP), polyethylene (PE), polycarbonate (PC), or the like. Here, polycarbonate is excellent in light resistance, heat resistance, and strength. The cover 2100 may be transparent and opaque so that the light source module 2200 is visible from the outside. The cover 2100 may be formed through blow molding.

The light source module 2200 may be disposed on one surface of the heat sink 2400. Thus, heat from the light source module 2200 is conducted to the heat sink 2400. The light source module 2200 may include a light source unit 2210, a connection plate 2230, and a connector 2250.

The member 2300 is disposed on an upper surface of the heat dissipator 2400 and has a plurality of light source parts 2210 and guide grooves 2310 into which the connector 2250 is inserted. The guide groove 2310 corresponds to the board and the connector 2250 of the light source unit 2210.

The surface of the member 2300 may be coated or coated with a light reflective material. For example, the surface of the member 2300 may be coated or coated with a white paint. The member 2300 is reflected on the inner surface of the cover 2100 to reflect the light returned to the light source module 2200 side again toward the cover 2100. Therefore, it is possible to improve the light efficiency of the lighting apparatus according to the embodiment.

The member 2300 may be made of an insulating material, for example. The connection plate 2230 of the light source module 2200 may include an electrically conductive material. Therefore, electrical contact may be made between the radiator 2400 and the connection plate 2230. The member 2300 may be formed of an insulating material to block an electrical short between the connection plate 2230 and the radiator 2400. The radiator 2400 receives heat from the light source module 2200 and heat from the power supply unit 2600 to radiate heat.

The holder 2500 may block the accommodating groove 2719 of the insulating portion 2710 of the inner case 2700. Therefore, the power supply unit 2600 accommodated in the insulating unit 2710 of the inner case 2700 is sealed. The holder 2500 has a guide protrusion 2510. The guide protrusion 2510 has a hole through which the protrusion 2610 of the power supply unit 2600 passes.

The power supply unit 2600 processes or converts an electrical signal provided from the outside to provide the light source module 2200. The power supply unit 2600 is accommodated in the accommodating groove 2725 of the inner case 2700, and is sealed in the inner case 2700 by the holder 2500.

The power supply unit 2600 may include a protrusion 2610, a guide unit 2630, a base 2650, and an extension unit 2670.

The guide part 2630 has a shape protruding outward from one side of the base 2650. The guide part 2630 may be inserted into the holder 2500. A plurality of parts may be disposed on one surface of the base 2650. The plurality of components may include, for example, a DC converter for converting AC power provided from an external power source into DC power, a driving chip for controlling the driving of the light source module 2200, and an ESD for protecting the light source module 2200. (ElectroStatic discharge) protection element and the like, but may not be limited thereto.

The extension part 2670 has a shape protruding outward from the other side of the base 2650. The extension part 2670 is inserted into the connection part 2750 of the inner case 2700 and receives an electrical signal from the outside. For example, the extension part 2670 may be provided to be equal to or smaller than the width of the connection part 2750 of the inner case 2700. Each end of the "+ wire" and the "-wire" may be electrically connected to the extension 2670, and the other end of the "+ wire" and the "-wire" may be electrically connected to the socket 2800. .

The inner case 2700 may include a molding unit together with the power supply unit 2600 therein. The molding part is a part where the molding liquid is hardened, so that the power supply part 2600 can be fixed inside the inner case 2700.

As shown in FIG. 19, the lighting apparatus according to the embodiment may include a cover 3100, a light source unit 3200, a radiator 3300, a circuit unit 3400, an inner case 3500, and a socket 3600. have. The light source unit 3200 may include a light emitting device or a light emitting device package according to the embodiment.

The cover 3100 has a bulb shape and is hollow. The cover 3100 has an opening 3110. The light source 3200 and the member 3350 may be inserted through the opening 3110.

The cover 3100 may be coupled to the radiator 3300 and may surround the light source unit 3200 and the member 3350. By combining the cover 3100 and the radiator 3300, the light source 3200 and the member 3350 may be blocked from the outside. The cover 3100 and the radiator 3300 may be coupled to each other through an adhesive, and may be coupled in various ways such as a rotation coupling method and a hook coupling method. The rotation coupling method is a method in which a screw thread of the cover 3100 is coupled to a screw groove of the heat sink 3300, and the cover 3100 and the heat sink 3300 are coupled by the rotation of the cover 3100. The hook coupling method is a method in which the jaw of the cover 3100 is fitted into the groove of the heat sink 3300 and the cover 3100 and the heat sink 3300 are coupled to each other.

The cover 3100 is optically coupled to the light source 3200. In detail, the cover 3100 may diffuse, scatter, or excite light from the light emitting device 3230 of the light source unit 3200. The cover 3100 may be a kind of optical member. Here, the cover 3100 may have a phosphor on the inside / outside or inside to excite the light from the light source unit 3200.

An inner surface of the cover 3100 may be coated with a milky paint. Here, the milky white paint may include a diffusion material for diffusing light. The surface roughness of the inner surface of the cover 3100 may be greater than the surface roughness of the outer surface of the cover 3100. This is to sufficiently scatter and diffuse the light from the light source unit 3200.

The cover 3100 may be made of glass, plastic, polypropylene (PP), polyethylene (PE), polycarbonate (PC), or the like. Here, polycarbonate is excellent in light resistance, heat resistance, and strength. The cover 3100 may be a transparent material that can be seen by the light source unit 3200 and the member 3350 from the outside, or may be an invisible opaque material. The cover 3100 may be formed through, for example, blow molding.

The light source unit 3200 may be disposed on the member 3350 of the radiator 3300 and may be disposed in plural. Specifically, the light source 3200 may be disposed on one or more side surfaces of the plurality of side surfaces of the member 3350. In addition, the light source 3200 may be disposed at an upper end of the side of the member 3350.

The light source unit 3200 may be disposed on three side surfaces of six side surfaces of the member 3350. However, the present invention is not limited thereto, and the light source unit 3200 may be disposed on all side surfaces of the member 3350. The light source 3200 may include a substrate 3210 and a light emitting device 3230. The light emitting device 3230 may be disposed on one surface of the substrate 3210.

The substrate 3210 has a rectangular plate shape, but is not limited thereto and may have various shapes. For example, the substrate 3210 may have a circular or polygonal plate shape. The substrate 3210 may be a circuit pattern printed on an insulator. For example, a printed circuit board (PCB), a metal core PCB, a flexible PCB, a ceramic PCB, and the like may be printed. It may include. In addition, it is possible to use a Chips On Board (COB) type that can directly bond the LED chip unpacked on the printed circuit board. In addition, the substrate 3210 may be formed of a material that efficiently reflects light, or may be formed of a color that reflects light efficiently, for example, white, silver, or the like. The substrate 3210 may be electrically connected to the circuit unit 3400 accommodated in the radiator 3300. The substrate 3210 and the circuit unit 3400 may be connected by, for example, a wire. A wire may pass through the radiator 3300 to connect the substrate 3210 and the circuit unit 3400.

The light emitting device 3230 may be a light emitting diode chip emitting red, green, or blue light or a light emitting diode chip emitting UV. The LED chip may be a horizontal type or a vertical type, and the LED chip may emit blue, red, yellow, or green. Can be.

The light emitting device 3230 may have a phosphor. The phosphor may be one or more of a Garnet-based (YAG, TAG), a silicate (Silicate), a nitride (Nitride) and an oxynitride (oxyxyride). Alternatively, the phosphor may be one or more of a yellow phosphor, a green phosphor, and a red phosphor.

The radiator 3300 may be coupled to the cover 3100 to radiate heat from the light source unit 3200. The radiator 3300 has a predetermined volume and includes an upper surface 3310 and a side surface 3330. A member 3350 may be disposed on the top surface 3310 of the heat sink 3300. An upper surface 3310 of the heat sink 3300 may be coupled to the cover 3100. The top surface 3310 of the heat sink 3300 may have a shape corresponding to the opening 3110 of the cover 3100.

A plurality of heat sink fins 3370 may be disposed on the side surface 3330 of the heat sink 3300. The heat radiating fins 3370 may extend outward from the side surface 3330 of the heat sink 3300 or may be connected to the side surface 3330. The heat dissipation fins 3370 may improve heat dissipation efficiency by widening a heat dissipation area of the heat dissipator 3300. Here, the side surface 3330 may not include the heat dissipation fins 3370.

The member 3350 may be disposed on an upper surface 3310 of the heat sink 3300. The member 3350 may be integrated with the top surface 3310 or may be coupled to the top surface 3310. The member 3350 may be a polygonal pillar. Specifically, the member 3350 may be a hexagonal pillar. The member 3350 of the hexagonal column has a top side and a bottom side and six sides. Here, the member 3350 may be a circular pillar or an elliptical pillar as well as a polygonal pillar. When the member 3350 is a circular pillar or an elliptic pillar, the substrate 3210 of the light source unit 3200 may be a flexible substrate.

The light source unit 3200 may be disposed on six side surfaces of the member 3350. The light source unit 3200 may be disposed on all six side surfaces, or the light source unit 3200 may be disposed on some of the six side surfaces. In FIG. 16, the light source unit 3200 is disposed on three side surfaces of the six side surfaces.

The substrate 3210 is disposed on the side surface of the member 3350. Side surfaces of the member 3350 may be substantially perpendicular to the top surface 3310 of the heat sink 3300. Accordingly, the substrate 3210 and the top surface 3310 of the heat sink 3300 may be substantially perpendicular to each other.

The material of the member 3350 may be a material having thermal conductivity. This is for receiving heat generated from the light source unit 3200 quickly. The material of the member 3350 may be, for example, aluminum (Al), nickel (Ni), copper (Cu), magnesium (Mg), silver (Ag), tin (Sn), or an alloy of the metals. Alternatively, the member 3350 may be formed of a thermally conductive plastic having thermal conductivity. Thermally conductive plastics are lighter than metals and have the advantage of having unidirectional thermal conductivity.

The circuit unit 3400 receives power from the outside and converts the received power to match the light source unit 3200. The circuit unit 3400 supplies the converted power to the light source unit 3200. The circuit unit 3400 may be disposed on the heat sink 3300. In detail, the circuit unit 3400 may be accommodated in the inner case 3500 and may be accommodated in the radiator 3300 together with the inner case 3500. The circuit unit 3400 may include a circuit board 3410 and a plurality of components 3430 mounted on the circuit board 3410.

The circuit board 3410 has a circular plate shape, but is not limited thereto and may have various shapes. For example, the circuit board 3410 may have an oval or polygonal plate shape. The circuit board 3410 may have a circuit pattern printed on an insulator.

The circuit board 3410 is electrically connected to the substrate 3210 of the light source unit 3200. The electrical connection between the circuit board 3410 and the substrate 3210 may be connected through, for example, a wire. A wire may be disposed in the heat sink 3300 to connect the circuit board 3410 and the board 3210.

The plurality of components 3430 may include, for example, a DC converter for converting an AC power provided from an external power source into a DC power source, a driving chip for controlling the driving of the light source unit 3200, and the protection of the light source unit 3200. Electrostatic discharge (ESD) protection element and the like.

The inner case 3500 accommodates the circuit unit 3400 therein. The inner case 3500 may have an accommodating part 3510 for accommodating the circuit part 3400.

For example, the accommodating part 3510 may have a cylindrical shape. The shape of the accommodating part 3510 may vary depending on the shape of the heat sink 3300. The inner case 3500 may be accommodated in the heat sink 3300. The accommodating part 3510 of the inner case 3500 may be accommodated in an accommodating part formed on a lower surface of the heat sink 3300.

The inner case 3500 may be coupled to the socket 3600. The inner case 3500 may have a connection part 3530 that is coupled to the socket 3600. The connection part 3530 may have a thread structure corresponding to the screw groove structure of the socket 3600. The inner case 3500 is an insulator. Therefore, an electrical short circuit between the circuit part 3400 and the heat sink 3300 is prevented. For example, the inner case 3500 may be formed of plastic or resin.

The socket 3600 may be coupled to the inner case 3500. In detail, the socket 3600 may be coupled to the connection part 3530 of the inner case 3500. The socket 3600 may have a structure such as a conventional conventional incandescent bulb. The circuit unit 3400 and the socket 3600 are electrically connected to each other. Electrical connection between the circuit unit 3400 and the socket 3600 may be connected through a wire. Therefore, when external power is applied to the socket 3600, the external power may be transferred to the circuit unit 3400. The socket 3600 may have a screw groove structure corresponding to the screw structure of the connection part 3550.

As shown in FIG. 20, the lighting apparatus, for example, the backlight unit includes a light guide plate 1210, a light emitting module unit 1240 for providing light to the light guide plate 1210, and a reflective member 1220 under the light guide plate 1210. ) And a bottom cover 1230 for accommodating the light guide plate 1210, the light emitting module unit 1240, and the reflective member 1220, but is not limited thereto.

The light guide plate 1210 serves to surface light by diffusing light. The light guide plate 1210 is made of a transparent material, for example, an acrylic resin series such as polymethyl metaacrylate (PMMA), polyethylene terephthlate (PET), polycarbonate (PC), cycloolefin copolymer (COC), and polyethylene naphthalate (PEN). It may include one of the resins.

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

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

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

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

The reflective member 1220 may be formed under the light guide plate 1210. The reflective member 1220 may improve the luminance of the backlight unit by reflecting the light incident on the lower surface of the light guide plate 1210 upward. The reflective member 1220 may be formed of, for example, PET, PC, or PVC resin, but is not limited thereto.

The bottom cover 1230 may accommodate the light guide plate 1210, the light emitting module unit 1240, the reflective member 1220, and the like. To this end, the bottom cover 1230 may be formed in a box shape having an upper surface opened, but is not limited thereto.

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

Although described above with reference to the drawings and embodiments, those skilled in the art will understand that the embodiments can be variously modified and changed without departing from the spirit of the embodiments described in the claims below. Could be.

The embodiment can improve the reliability of the light emitting device.

Claims

Board;

A first conductivity type semiconductor layer disposed on the substrate;

An active layer disposed on the first conductivity type semiconductor layer;

A second conductivity type semiconductor layer disposed on the active layer; And

A hole injection layer including a first hole injection layer disposed between the active layer and the second conductive semiconductor layer and undoped, and a second hole injection layer disposed on the first hole injection layer and doped with a p-type dopant;

Light emitting device comprising a.
The method of claim 1,

The p-type dopant is Mg, Zn, Ca, Sr, Be comprising a light emitting device.
The method of claim 2,

A light emitting device including the first hole injection layer and the second hole injection layer is In x Al y Ga 1 -x- y N (0 <x≤1, 0 <y≤1, 0 <x + y≤1) .
The method of claim 3, wherein

The hole injection layer has a thickness of 15 kHz to 25 kHz.
The method of claim 4, wherein

The ratio of the thickness of the first hole injection layer and the thickness of the second hole injection layer is 1: 1 to 1: 3.
The method of claim 1,

The p-type dopant concentration is 1E18 to 3E20 light emitting device.
The method of claim 6,

The p-type dopant of the second hole injection layer has the same concentration value in the thickness direction.
The method of claim 6,

The p-type dopant of the second hole injection layer is a light emitting device that the concentration value increases in the thickness direction.
The method of claim 1,

A light emitting device in which a plurality of first and second hole injection layers are arranged in pairs on the hole injection layer.
The method of claim 1,

The hole injection layer further comprises a third hole injection layer including InN.
The method of claim 10,

The third hole injection layer is a light emitting device disposed between the first hole injection layer and the second hole injection layer.
The method of claim 10,

The third hole injection layer is disposed between the active layer and the first hole injection layer.
The method of claim 10,

The third hole injection layer has a thickness of 5 Å or less.
The method of claim 1,

The hole injection layer further comprises a third hole injection layer having a p-type dopant concentration of 1/2 or less of the second hole injection layer.
The method of claim 14,

The third hole injection layer is disposed between the active layer and the first hole injection layer.
The method of claim 15,

The third hole injection layer includes a GaN, InGaN, AlGaN, InAlGaN.
The method of claim 1,

And a buffer layer and a strain control layer disposed between the substrate and the first conductive semiconductor layer.
The method of claim 1,

And a current spreading layer disposed between the first conductive semiconductor layer and the active layer.
The method of claim 1,

The light emitting device further comprising a translucent electrode layer disposed on the second conductive semiconductor layer.
20. An illumination system comprising the light emitting device of any one of claims 1-19.