KR20140072606A - Light emittng device - Google Patents

Abstract

According to an embodiment of the present invention, a light emitting device includes: a first conductive semiconductor layer; an active layer arranged on the first conductive semiconductor layer; and a second conductive semiconductor layer which is arranged on the active layer and includes an electron blocking layer. The electron blocking layer includes an AlGaN layer, an MgN layer, and an undoped GaN layer.

Description

[0001] LIGHT EMITTING DEVICE [0002]

An embodiment relates to a light emitting element.

GaN, and AlGaN are widely used for optoelectronics and electronic devices due to their advantages such as wide and easy bandgap energy.

Particularly, a light emitting device such as a light emitting diode (Ligit Emitting Diode) or a laser diode using a semiconductor material of a 3-5 group or a 2-6 group compound semiconductor has been widely used in various fields such as red, green, blue and ultraviolet It can realize various colors, and it can realize efficient white light by using fluorescent material or color combination. It has low power consumption, semi-permanent lifetime, fast response speed, safety, and environment compared to conventional light sources such as fluorescent lamps and incandescent lamps Affinity.

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.

1 is a view showing a conventional light emitting device.

A conventional light emitting device 100 includes a buffer layer 115 and a light emitting structure disposed on a substrate 110 made of sapphire or the like and the light emitting structure includes a first conductive semiconductor layer 120 and an active layer 130, The first electrode 170 and the second electrode 180 are disposed on the first conductivity type semiconductor layer 120 and the second conductivity type semiconductor layer 140, respectively.

Electrons injected through the first conductivity type semiconductor layer 120 and holes injected through the second conductivity type semiconductor layer 140 meet with each other to form an energy band unique to the active layer 130 And emits light having energy determined by the light intensity. The light emitted from the active layer 130 may be different depending on the composition of the active layer 130 and may be blue light, ultraviolet (UV) light or deep ultraviolet (UV) light.

2 is a detailed view illustrating the structure of the light emitting structure of FIG.

The second conductive semiconductor layer 140 may include a p-InAlGaN layer 142, a p-AlGaN layer 144 and a p-GaN layer 146. The p- Lt; / RTI >

However, due to the bonding energy of aluminum, it is difficult for the dopant such as magnesium (Mg) to be made into holes. That is, in order to increase the electron blocking effect, aluminum may be included in the electron blocking layer. In this case, the doping of magnesium is not easy, so that the hole injection effect may be decreased and the decrease of the hole injection may lead to a decrease in the luminous efficiency in the active layer . In addition, if the amount of magnesium to be implanted is increased, the quality of the conductive type semiconductor layer may be deteriorated.

The embodiment attempts to improve the luminous efficiency of the light emitting device by preventing deterioration in quality while increasing the electron blocking effect and the hole injection effect of the electron blocking layer of the light emitting device.

The embodiment includes a first conductivity type semiconductor layer; An active layer disposed on the first conductive semiconductor layer; And a second conductive type semiconductor layer disposed on the active layer and including an electron blocking layer, wherein the electron blocking layer includes an AlGaN layer, an MgN layer, and an undoped GaN layer.

Another embodiment includes a first conductive semiconductor layer; An active layer disposed on the first conductive semiconductor layer; And a second conductive type semiconductor layer disposed on the active layer and including an electron blocking layer, wherein the electron blocking layer includes an AlGaN layer, an MgN layer, and an InGaN layer.

The electron blocking layer may be arranged alternately 1 to 50 times.

The AlGaN layer may be of the second conductivity type.

The AlGaN layer may have a thickness of 1 nanometer to 50 nanometers.

The undoped GaN layer and / or the InGaN layer may have a thickness of 1 nanometer to 50 nanometers.

The light emitting device may further include an InAlGaN layer disposed in the second conductivity type semiconductor layer and disposed between the active layer and the electron blocking layer.

The InAlGaN layer may be of the second conductivity type.

The AlGaN layer may be disposed closest to the active layer in the electron blocking layer, the undoped GaN layer may be disposed the farthest from the active layer, and the InGaN layer may be disposed farthest from the active layer.

The light emitting device may further include a second conductive type GaN layer disposed in the second conductive type semiconductor layer, and the second conductive type GaN layer may be disposed in a direction opposite to the active layer with respect to the electron blocking layer.

The electron blocking layer may be arranged such that the AlGaN layer, the MgN layer, and the undoped GaN layer are alternately disposed at least twice, and the MgN layer may be disposed in the region in contact with the second conductivity type GaN layer.

The electron blocking layer may be arranged such that the AlGaN layer, the MgN layer, and the InGaN layer are alternately disposed at least twice, and the MgN layer may be disposed in a region in contact with the second conductive GaN layer.

The light emitting device according to the present embodiment includes an AlGaN layer, an MgN layer, and an undoped GaN layer as electron blocking layers, which improves the electron blocking effect and the hole injecting effect while improving the current spreading and improving the light efficiency of the light emitting device great.

1 is a view showing a conventional light emitting device,
FIG. 2 is a detailed view of the structure of the light emitting structure of FIG. 1,
3 is a detailed view showing a structure of a light emitting structure of a light emitting device according to an embodiment,
FIGS. 4A and 4B are views showing the configuration of one embodiment of the electron blocking layer of FIG. 3,
5A to 5G are views showing a manufacturing process of an embodiment of a light emitting device,
6 is a view showing another embodiment of the light emitting device,
7 is a detailed view of the structure of a light emitting structure of another embodiment of the light emitting device,
8A and 8B are diagrams showing configurations of one embodiment of the electron blocking layer of FIG. 7,
9 is a view showing an embodiment of a light emitting device package in which a light emitting device is disposed,
10 is a view showing an embodiment of a lighting device in which a light emitting element is disposed,
11 is a view showing an embodiment of a video display device in which a light emitting device is arranged.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

In the description of the embodiment according to the present invention, in the case of being described as being formed "on or under" of each element, the upper (upper) or lower (lower) or under are all such that two elements are in direct contact with each other or one or more other elements are indirectly formed between the two elements. Also, when expressed as "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

FIG. 3 is a detailed view illustrating the structure of a light emitting structure of one embodiment of the light emitting device, and FIGS. 4A and 4B are views showing the structure of one embodiment of the electron blocking layer of FIG.

The light emitting structure of the light emitting device according to the present embodiment may include a first conductive semiconductor layer 220, an active layer 230, and a second conductive semiconductor layer 240.

The first conductive semiconductor layer 220 may be formed of a semiconductor compound. Group 3-Group 5, Group 2-Group 6, and the like, and the first conductive type dopant may be doped. When the first conductive semiconductor layer 220 is an n-type semiconductor layer, the first conductive dopant may include Si, Ge, Sn, Se, and Te as an n-type dopant.

The first conductive semiconductor layer 220 includes 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? can do. The first conductive semiconductor layer 220 may be formed of one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP and InP.

The active layer 230 is formed on the active layer 230 by electrons injected through the first conductive semiconductor layer 220 and holes injected through the second conductive semiconductor layer 240 by energy bands unique to the active layer 230 And is a layer that emits light having energy to be determined.

The active layer 230 may be formed of a material selected from the group consisting of a double heterojunction structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum-wire structure, or a quantum dot structure Or at least one of them may be formed. For example, the active layer 230 may be formed with a multiple quantum well structure by injecting trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) But is not limited thereto.

The well layer / barrier layer of the active layer 230 may be formed of any one of InGaN / GaN, InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, InAlGaN / InAlGaN, GaAs (InGaAs) / AlGaAs, GaP But it is not limited thereto. The well layer may be formed of a material having a band gap lower than the band gap of the barrier layer.

A conductive clad layer (not shown) may be formed on and / or below the active layer 230. The conductive cladding layer may be formed of a semiconductor having a band gap wider than the barrier layer or band gap of the active layer 230. For example, the conductive clad layer may include GaN, AlGaN, InAlGaN, superlattice structure, or the like. Further, the conductive clad layer may be doped with n-type or p-type.

A second conductive type semiconductor layer is disposed on the active layer 230. The second conductivity type semiconductor layer may include a p-InAlGaN layer 242, an electron blocking layer 244 and a p-GaN layer 246 from the active layer 230 direction. The electron blocking layer 244 may include AlGaN / MgN / undoped GaN (u-GaN).

In the embodiment shown in FIG. 4A, an electron blocking layer is formed by arranging AlGaN layer 244a / MgN layer 244b / undoped GaN layer (u-GaN) 244c a plurality of times, Up to 50 times.

Here, the AlGaN layer 244a may be doped p-type for reasons such as being partially supplied from the MgN layer 244b without dopant supply in the manufacturing process, and the thickness t ₁ ). MgN layer (244b) is formed into a thin film is difficult to measure the thickness (t _2), an undoped GaN layer (244c) may have a thickness (t ₃₎ of 1 nanometer to 50 nanometers.

In Fig. 4A, the AlGaN layer 244a may be disposed in the active layer direction and the undoped GaN layer 244c may be disposed the farthest from the active layer. The combination of the AlGaN layer 244a / MgN layer 244b / undoped GaN layer 244c disposed in the electron blocking layer is referred to as a first electron blocking layer 244 ₁ to an nth electron blocking layer 244 _n , .

The second conductivity type semiconductor layer having the electron blocking layer structure of FIG. 4A may include a second conductivity type GaN layer disposed in contact with the n-th electron blocking layer 244 _n , And may be disposed in the direction opposite to the active layer with respect to the electron blocking layer.

The structure of the electron blocking layer shown in FIG. 4B is similar to the structure shown in FIG. 4A, except that the last n-th electron blocking layer 244n consists of only the AlGaN layer 244a and the MgN layer 244b. That is, the first electron blocking layer 244 ₁ to the ( _n-1 ) _th electron blocking layer 244 _n-1 are different from each other in the composition and configuration of the last _n-th electron blocking layer 244 _n . Therefore, the MgN layer 244b may be disposed in the region contacting the p-GaN layer 246 described above, and the p-GaN layer may be doped more p-type than in the embodiment shown in FIG. 4A have. On the other hand, the embodiment shown in FIG. 4A can perform the current spreading better than the present embodiment, but the resistance is larger and the operating voltage can be increased.

The p-GaN layer 246 may be formed of a semiconductor compound, and may be formed of a compound semiconductor such as Group 3-Group 5, Group 2-Group 6, or the like, and may be doped with a p-type dopant. Further, it may include 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) Zn, Ca, Sr, Ba, and the like.

The electron blocking layer 244 should block electrons injected from the active layer direction and facilitate the injection of holes from the p-GaN layer 246. The AlGaN layer 244a has a higher quality than that of the conventional p-AlGaN but does not contain a dopant, so that the hole injection effect may be lowered, so that the MgN layer 244b may be added to improve the hole injection effect. The undoped GaN layer 244c may be disposed on the entire surface of the light emitting structure and the undoped GaN layer 244c may be formed on the MgO layer 244c so that the current Spreading and crystal quality can be improved.

5A to 5G are views showing a manufacturing process of an embodiment of a light emitting device.

First, as shown in FIG. 5A, a buffer layer 215, a first conductive semiconductor layer 220, and an active layer 230 are grown on a substrate 210.

The substrate 210 may be formed of a material suitable for semiconductor material growth or a carrier wafer, may be formed of a material having excellent thermal conductivity, and may include a conductive substrate or an insulating substrate. For example, at least one of sapphire (Al ₂ O ₃ ), SiO ₂ , SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge and Ga ₂ O ₃ can be used.

The buffer layer 215 may be formed of at least one of AlAs, GaN, InN, InGaN, AlGaN, InAlGaN, and AlInN in addition to a Group III-V compound semiconductor such as AlN.

When a substrate 210 is formed of sapphire or the like and a light emitting structure including GaN or AlGaN is disposed on the substrate 210, the lattice mismatch between GaN and AlGaN and sapphire is very large, A dislocation, a melt-back, a crack, a pit, and a defective surface morphology, which deteriorate the crystallinity, may occur because the difference in thermal expansion coefficient is very large, As the buffer layer 215, AlN or the like can be used.

Although not shown, an undoped GaN layer or an AlGaN layer may be disposed between the buffer layer 220 and the light emitting structure to prevent the potentials and the like from being transmitted into the light emitting structure.

The light emitting structure includes a first conductive semiconductor layer 220, an active layer 230, and a second conductive semiconductor layer.

The first conductive semiconductor layer 220 may be formed using an AlGaN layer doped with an n-type dopant by using a chemical vapor deposition (CVD) method, molecular beam epitaxy (MBE), sputtering or vapor phase epitaxy (HVPE) Can be formed. The first conductive semiconductor layer 220 may be formed by depositing a silane gas containing an n-type impurity such as trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ) (SiH ₄ ) may be implanted.

The active layer 230 may be formed by implanting trimethylgallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) But is not limited thereto.

Then, a second conductivity type semiconductor layer is grown on the active layer 230 as shown in FIGS. 5B to 5F.

In FIG. 5B, the InAlGaN layer 242 is grown on the active layer 230, and the second conductivity type, that is, the p-type dopant may be added to grow the p-type.

5C to 5E, the AlGaN layer 244a, the MgN layer 244b, and the undoped GaN layer 244c may be successively grown to form the electron blocking layer.

In FIG. 5C, the AlGaN layer 244a is grown by supplying TMAL, TMGa, and NH ₃ , and the MgN layer 244b is grown by supplying Cp ₂ Mg and NH ₃ in FIG. 5D. The amount of magnesium (Mg) Can supply 1 to 4 times the amount of magnesium that was conventionally doped with a dopant. In FIG. 5D, magnesium is supplied for 5 seconds to 60 seconds with Cp ₂ Mg and NH ₃ , and if supplied for too short time, doping is not performed properly, and if supplied for too long, crystal quality may be deteriorated.

In FIG. 5E, the undoped GaN layer 244c can be grown by supplying TMGa and NH ₃ . The processes of Figs. 5C to 5E are repeated one to fifty times in sequence, so that the AlGaN layer 244a, the MgN layer 244b and the undoped GaN layer 244c are repeatedly disposed one to fifty times in the electron blocking layer .

4B, the AlGaN layer 244a, the MgN layer 244b, and the undoped GaN layer 244c are alternately arranged in the electron blocking layer a plurality of times, and the second conductivity type GaN layer 246 The MgN layer 244b may be disposed. That is, in the electron blocking layer, the AlGaN layer 244a and the MgN layer 244b are disposed in the region farthest from the active layer 230, and the growth of the undoped GaN layer 244c can be omitted.

The AlGaN layer 244a may be doped with a second conductive dopant or p-type dopant and may be grown to a thickness of 1 nanometer to 50 nanometers and the undoped GaN layer 244c may have a thickness of 1 nanometer to 50 nanometers Lt; RTI ID = 0.0 > nanometers. ≪ / RTI >

The second conductive GaN layer 246 may be grown as shown in FIG. 5F. The grown second conductive GaN layer 246 may be disposed in a direction opposite to the active layer 230 with respect to the electron blocking layer. .

5G, a side surface of the light emitting structure may include a part of the electron blocking layer 244, the active layer 230, and a part of the first conductivity type semiconductor layer 220 from the second conductive type GaN layer 246 A part of the first conductivity type semiconductor layer 220 may be exposed. Such a mesa etch structure may be useful when using the substrate 210 as an insulating material.

The first electrode 270 may be disposed on a surface of the exposed first conductive semiconductor layer 220 and the second electrode 280 may be disposed on a surface of the second conductive GaN layer 246. At least one of the first electrode 270 and the second electrode 280 may include at least one of aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), copper (Cu) And may be formed as a single layer or a multi-layer structure.

FIG. 5G shows a horizontal light emitting device including the electron blocking layer, and FIG. 6 shows a vertical light emitting device including the above-described electron blocking layer as another embodiment of the light emitting device.

In the light emitting device shown in FIG. 6, the first conductive semiconductor layer 220 and the active layer 230 that constitute the light emitting structure, the p-InAlGaN layer 242 and the electron blocking layer 244 in the second conductive semiconductor layer, the composition of the p-GaN layer 246 and the composition of the AlGaN layer 244a / MgN layer 244b / undoped GaN layer (u-GaN) 244c in the electron blocking layer 244 and the composition of the first electrode 270 ) Is the same as the embodiment shown in Fig. 5G and the like.

The ohmic layer 282, the reflective layer 284, the bonding layer 286, and the conductive supporting substrate 288 are disposed at the bottom of the light emitting structure, specifically, below the p-GaN layer 246, .

The ohmic layer 282 may be about 200 Angstroms thick. The ohmic layer 282 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide ), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO nitride), AGZO (Al- Ga ZnO), IGZO , NiO, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, Ru, Au, and Hf, and is not limited to such a material.

The reflective layer 284 may comprise a metal layer comprising aluminum (Al), silver (Ag), nickel (Ni), platinum (Pt), rhodium (Rh), or an alloy comprising Al, Ag, Pt or Rh . When the above-described semiconductor device is a light-emitting device, aluminum, silver, or the like can effectively reflect light generated in the active layer 230, thereby greatly improving the light extraction efficiency of the semiconductor device.

Since the metal support 288 can use a metal having a high electrical conductivity and sufficiently dissipate heat generated during operation of the semiconductor device, a metal having high thermal conductivity can be used.

The conductive support substrate 288 may be formed of a metal or a semiconductor material or the like. And may be formed of a material having high electrical conductivity and high thermal conductivity. For example, a material selected from the group consisting of molybdenum (Mo), silicon (Si), tungsten (W), copper (Cu) and aluminum (Al) (Cu-W), a carrier wafer (e.g., GaN, Si, Ge, GaAs, ZnO, SiGe, SiC, SiGe, Ga ₂ O _3, etc.) And the like.

The conductive support substrate 288 may have a mechanical strength enough to separate the entire nitride semiconductor into separate chips through a scribing process and a breaking process without causing warpage of the entire nitride semiconductor.

The bonding layer 286 bonds the reflective layer 264 and the conductive support substrate 288 and may be formed of one of gold (Au), tin (Sn), indium (In), aluminum (Al), silicon (Si) , Nickel (Ni), and copper (Cu), or an alloy thereof.

The surface of the first conductive semiconductor layer 220 may be patterned to improve the light extracting effect. The portion where the first electrode 270 is disposed may be flat, and the light emitting structure 220 The passivation layer 290 may be formed of an insulating material and the insulating material may be made of a non-conductive oxide or nitride. As an example, the passivation layer 290 may be formed of a silicon oxide (SiO ₂ ) layer, an oxynitride layer, or an aluminum oxide layer.

7 is a detailed view of the structure of a light emitting structure of another embodiment of the light emitting device, and FIGS. 8A and 8B are views showing the structure of one embodiment of the electron blocking layer of FIG.

The light emitting device according to the present embodiment differs in that the light emitting device 7 is similar to the light emitting device of FIG. 3 except that the InGaN layer 245c is disposed instead of the undoped GaN layer 244c. The electron blocking layer 245 may be disposed from the AlGaN layer 245a / the MgN layer 245b / the InGaN layer 245c a plurality of times.

Here, the AlGaN layer 245a may be doped p-type for reasons such as a part being supplied from the MgN layer 245b without supplying a dopant in the manufacturing process, and the thickness t ₁ ). The MgN layer 245b is formed as a thin film to make it difficult to measure the thickness t ₂ and the InGaN layer 245c may have a thickness t ₃ of 1 nm to 50 nm.

In Fig. 8A, the AlGaN layer 245a may be disposed in the active layer direction and the InGaN layer 245c may be disposed the farthest from the active layer. The combination of the AlGaN layer 245a / MgN layer 245b / InGaN layer 245c disposed in the electron blocking layer is referred to as a first electron blocking layer 245 ₁ to an nth electron blocking layer 245 _n .

The second conductivity type semiconductor layer having the electron blocking layer structure of FIG. 8A may include a second conductivity type GaN layer disposed in contact with the n-th electron blocking layer 245 _n , And may be disposed in the direction opposite to the active layer with respect to the electron blocking layer.

The structure of the electron blocking layer shown in FIG. 8B is similar to that shown in FIG. 8A, except that the n-th electron blocking layer 245n disposed at the end consists of only the AlGaN layer 245a and the MgN layer 245b. That is, the first electron blocking layer 245 ₁ to the ( _n-1 ) _th electron blocking layer 245 _n-1 are different from each other in composition and configuration of the last _n- th electron blocking layer 245 _n . Therefore, the MgN layer 245b may be disposed in the region contacting the p-GaN layer 246 described above, and the p-GaN layer may be doped more p-type than in the embodiment shown in FIG. 8A have. On the other hand, the embodiment shown in FIG. 8A is better in current spreading than the present embodiment, but the resistance is larger, so that the operating voltage can be increased.

The electron blocking layer 245 should be capable of blocking electrons injected from the active layer direction and facilitating the injection of holes from the p-GaN layer 246. The AlGaN layer 245a has a higher quality than that of the conventional p-AlGaN but does not contain a dopant, which may lower the hole injecting effect, so that the MgN layer 245b can be added to improve the hole injecting effect. In the embodiment described above, the undoped GaN layer 244c can improve the quality of the crystal to enhance the function of the electron blocking layer 244. In this embodiment, the InGaN layer 245c has the electron blocking layer 245 The manufacturing method of the light emitting device of FIGS. 7 to 8B is the same as the method shown in FIGS. 5A to 5G except that the undoped GaN layer 244c is replaced by InGaN Layer 245c. ≪ / RTI > That is, the AlGaN layer 245a, the MgN layer 245b, and the InGaN layer 245c can be grown repeatedly once to 50 times to form the electron blocking layer 245, and the InGaN layer 245c can be grown to a thickness of 1 nm To 50 nanometers in thickness.

The electron blocking layer having the above-described structure can also be applied to the vertical light emitting device shown in Fig.

9 is a view illustrating an embodiment of a light emitting device package in which a light emitting device is disposed.

The light emitting device package 300 according to the embodiment is a flip chip type light emitting device package including a body 310 including a cavity and a first lead frame 321 and a second lead frame 322 provided on the body 310, A light emitting device 200 according to the above-described embodiments, which is electrically connected to the first lead frame 321 and the second lead frame 322, installed in the body 310, And a molding part 350 formed in the cavity.

The body 310 may be formed of a silicon material, a synthetic resin material, or a metal material. When the body 310 is made of a conductive material such as a metal material, an insulating layer is coated on the surface of the body 310 to prevent an electrical short between the first and second lead frames 321 and 322 .

The first lead frame 321 and the second lead frame 322 are electrically disconnected from each other and supply current to the light emitting device 200. The first lead frame 321 and the second lead frame 322 may reflect the light generated from the light emitting device 200 to increase the light efficiency, It may be discharged.

The light emitting device 200 may be electrically connected to the first lead frame 321 and the second lead frame 322 by ball solder 340 and may be electrically connected to the lead frame and the body Can be fixed.

The molding part 350 may surround and protect the light emitting device 200. In addition, the phosphor 360 is conformally coated on the molding part 350 as a separate layer from the molding part 350. In this structure, the phosphors 360 are distributed so that the wavelength of the light emitted from the light emitting device 200 can be changed in the entire region where the light of the light emitting device package 300 is emitted.

The light in the first wavelength range emitted from the light emitting device 200 is excited by the phosphor 360 and converted into light in the second wavelength range and light in the second wavelength range passes through the lens (not shown) The light path can be changed.

The light emitting device disposed inside the light emitting device package 300 includes an AlGaN layer, an MgN layer, and an undoped GaN layer, which are electron blocking layers, and is excellent in electron blocking effect, hole injection effect and quality, So that the light efficiency of the light emitting device is also excellent.

The light emitting device package 300 may be mounted on one or a plurality of light emitting devices according to the embodiments described above, but the present invention is not limited thereto.

A plurality of light emitting device packages according to embodiments may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, and the like may be disposed on the light path of the light emitting device package. Such a light emitting device package, a substrate, and an optical member can function as a light unit. Still another embodiment may be implemented as a display device, an indicating device, a lighting system including the semiconductor light emitting device or the light emitting device package described in the above embodiments, for example, the lighting system may include a lamp, a streetlight . Hereinafter, a head lamp and a backlight unit will be described as an embodiment of an illumination system in which the above-described light emitting device package is disposed.

10 is a view showing an embodiment of a headlamp in which a light emitting device package is disposed.

The light emitted from the light emitting device module 401 in which the light emitting device package is disposed is reflected by the reflector 402 and the shade 403 and then transmitted through the lens 404 to the front of the vehicle body You can head.

As described above, the light emitting device used in the light emitting device module 401 is composed of an AlGaN layer, an MgN layer, and an undoped GaN layer, which are electron blocking layers, and is excellent in electron blocking effect and hole injection effect and quality, The current spreading is increased in the conductive type semiconductor layer, and the light efficiency of the light emitting element is also excellent.

11 is a view showing an embodiment of a video display device in which a light emitting device is arranged.

As shown in the drawing, the image display apparatus 500 according to the present embodiment includes a light source module, a reflection plate 520 on the bottom cover 510, and a reflection plate 520 disposed in front of the reflection plate 520, A first prism sheet 550 and a second prism sheet 560 disposed in front of the light guide plate 540 and a second prism sheet 560 disposed between the first prism sheet 560 and the second prism sheet 560, A panel 570 disposed in front of the panel 570 and a color filter 580 disposed in the front of the panel 570.

The light source module comprises a light emitting device package 535 on a circuit board 530. Here, the circuit board 530 may be a PCB or the like, and the light emitting device package 535 is the same as that described with reference to FIG.

The bottom cover 510 can house the components in the image display apparatus 500. The reflective plate 520 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 540 or on the front surface of the bottom cover 510 with a highly reflective material.

The reflector 520 can be made of a material having a high reflectance and can be used in an ultra-thin shape, and a polyethylene terephthalate (PET) can be used.

The light guide plate 540 scatters the light emitted from the light emitting device package module so that the light is uniformly distributed over the entire screen area of the LCD. Accordingly, the light guide plate 530 is made of a material having a good refractive index and transmittance. The light guide plate 530 may be formed of poly methylmethacrylate (PMMA), polycarbonate (PC), or polyethylene (PE). Also, if the light guide plate 540 is omitted, an air guide display device can be realized.

The first prism sheet 550 is formed on one side of the support film with a translucent and elastic polymer material. The polymer may have a prism layer in which a plurality of steric structures are repeatedly formed. As shown in the drawings, the plurality of patterns may be repeatedly provided with a stripe pattern.

In the second prism sheet 560, a direction of a floor and a valley of one side of the supporting film may be perpendicular to a direction of a floor and a valley of one side of the supporting film in the first prism sheet 550. This is for evenly distributing the light transmitted from the light source module and the reflective sheet in all directions of the panel 570.

In this embodiment, the first prism sheet 550 and the second prism sheet 560 constitute an optical sheet, which may be made of other combinations, for example, a microlens array or a combination of a diffusion sheet and a microlens array Or a combination of one prism sheet and a microlens array, or the like.

A liquid crystal display (LCD) panel may be disposed on the panel 570. In addition to the liquid crystal display panel 560, other types of display devices requiring a light source may be provided.

In the panel 570, a liquid crystal is positioned between glass bodies, and a polarizing plate is placed on both glass bodies to utilize the polarization of light. Here, the liquid crystal has an intermediate property between a liquid and a solid, and liquid crystals, which are organic molecules having fluidity like a liquid, are regularly arranged like crystals. The liquid crystal has a structure in which the molecular arrangement is changed by an external electric field And displays an image.

A liquid crystal display panel used in a display device is an active matrix type, and a transistor is used as a switch for controlling a voltage supplied to each pixel.

A color filter 580 is provided on the front surface of the panel 570 so that only the red, green, and blue light is transmitted through the panel 570 for each pixel.

The light emitting device disposed in the image display device according to the present embodiment includes an AlGaN layer, an MgN layer, and an undoped GaN layer, which are electron blocking layers, and is excellent in electron blocking effect, hole injection effect and quality, And the light efficiency of the light emitting device is also excellent.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

100: light emitting device 110: buffer layer
120: first conductivity type semiconductor layer 130: active layer
140: second conductivity type semiconductor layer 142, 242: p-InAlGaN layer
144: p-AlGaN layer 146, 246: p-GaN layer
150: transparent conductive layer 170: first electrode
180: second electrode 244, 245: electron blocking layer
244a, 245a: AlGaN layer 244b, 245b: MgN layer
244c: undoped GaN layer 245c: InGaN layer
282:
284: reflective layer 286: bonding layer
288: Conductive support substrate 290: Passivation layer
300: light emitting device package 310: body
321, 322: first and second lead frames 340: solder
350: molding part 360: phosphor layer
400: head lamp 410: light emitting element module
402: Reflector 403: Shade
404: Lens 500: Display device
510: bottom cover 520: reflector
530: circuit board module 540: light guide plate
550, 560: first and second prism sheets 570:
580: Color filter

Claims (15)

A first conductive semiconductor layer;
An active layer disposed on the first conductive semiconductor layer; And
And a second conductive type semiconductor layer disposed on the active layer and including an electron blocking layer,
Wherein the electron blocking layer comprises an AlGaN layer, a MgN layer, and an undoped GaN layer. A first conductive semiconductor layer;
An active layer disposed on the first conductive semiconductor layer; And
And a second conductive type semiconductor layer disposed on the active layer and including an electron blocking layer,
Wherein the electron blocking layer comprises an AlGaN layer, a MgN layer, and an InGaN layer. 3. The method according to claim 1 or 2,
Wherein the electron blocking layer is disposed alternately one to fifty times. 3. The method according to claim 1 or 2,
Wherein the AlGaN layer is a second conductive type. 3. The method according to claim 1 or 2,
Wherein the AlGaN layer has a thickness of 1 nanometer to 50 nanometers. The method according to claim 1,
Wherein the undoped GaN layer has a thickness of 1 nanometer to 50 nanometers. 3. The method of claim 2,
Wherein the InGaN layer has a thickness of 1 nanometer to 50 nanometers. 3. The method according to claim 1 or 2,
And an InAlGaN layer disposed in the second conductivity type semiconductor layer and disposed between the active layer and the electron blocking layer. 9. The method of claim 8,
And the InAlGaN layer is a second conductive type. The method according to claim 1,
Wherein the AlGaN layer is disposed closest to the active layer in the electron blocking layer and the undoped GaN layer is disposed farthest from the active layer. 3. The method of claim 2,
Wherein the AlGaN layer is disposed closest to the active layer in the electron blocking layer and the InGaN layer is disposed farthest from the active layer. The method according to claim 1,
And a second conductive type GaN layer disposed in the second conductive type semiconductor layer, wherein the second conductive type GaN layer is disposed in a direction opposite to the active layer with respect to the electron blocking layer. 13. The method of claim 12,
Wherein the electron blocking layer is arranged such that the AlGaN layer, the MgN layer, and the undoped GaN layer are alternately arranged at least twice, and the MgN layer is disposed in a region in contact with the second conductive GaN layer. 3. The method of claim 2,
And a second conductive type GaN layer disposed in the second conductive type semiconductor layer, wherein the second conductive type GaN layer is disposed in a direction opposite to the active layer with respect to the electron blocking layer. 15. The method of claim 14,
Wherein the electron blocking layer is arranged such that the AlGaN layer, the MgN layer, and the InGaN layer are alternately arranged at least twice, and the MgN layer is disposed in a region in contact with the second conductive GaN layer.

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