KR20120045536A - Light emitting device and fabrication method thereof - Google Patents

Abstract

PURPOSE: A light emitting device and a manufacturing method thereof are provided to prevent a current concentration phenomenon by forming a light transmissive electrode layer on the entire outer surface of a second conductivity type semiconductor layer. CONSTITUTION: A light emitting device comprises a substrate and a light emitting structure(100). The light emitting structure located on the substrate includes a first conductivity type semiconductor layer, and active layer(120), and a second conductivity type semiconductor layer(130). The second conductivity type semiconductor layer includes a first layer and a second layer arranged on the first layer. The first layer and the second layer are alternatively laminated twice. The impurity doping concentration of the second layer is greater than the impurity doping concentration of the first layer.

Description

Light emitting device and manufacturing method thereof

The embodiment relates to a light emitting device and a method of manufacturing the same.

Light Emitting Device (LED) is a device that converts an electric signal into a form of light such as infrared rays, visible rays or ultraviolet rays by using the characteristics of a compound semiconductor, and is used for home appliances, remote controls, electronic displays, indicators, and various automation devices. It is used, and the use area of the light emitting device is gradually increasing.

As the use area of the light emitting device becomes wider as described above, the luminance required for electric light used for living, electric light for rescue signals, and the like is increased. Therefore, it is important to increase the light emission luminance of the light emitting device.

On the other hand, the light emission of the light emitting device is due to the recombination of the electron (Electrode) and the hole (Hall), because the hole is usually less mobility than the electron, the number is smaller than the electron, the electron and the hole actually recombination The light emission luminance of the resulting light emitting device depends on the holes.

However, when the doping concentration of the impurity is increased to increase the concentration of the holes, the crystal structure of the semiconductor layer may be lowered and the surface may be roughened. Accordingly, the luminous efficiency and luminance of the light emitting device may be lowered.

The embodiment provides a light emitting device capable of improving light emission luminance by increasing hole concentration and hole mobility without deteriorating crystal quality of a semiconductor layer, and a method of manufacturing the same.

The light emitting device according to the embodiment includes a light emitting structure disposed on the substrate and the substrate, the light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer, wherein the second conductive semiconductor layer comprises a first layer and a first layer. And a second layer of phases, wherein the first layer and the second layer are alternately stacked at least twice alternately with each other, and the impurity doping concentration of the second layer may be greater than the impurity doping concentration of the first layer.

In addition, the second conductive semiconductor layer may be an InAlGaN, AlGaN, InGaN, or GaN semiconductor layer.

In addition, the Ga inclusion amount of the first layer may be larger than the Ga inclusion amount of the second layer.

In addition, the impurities may include at least one of Mg, Zn, Ca, Sr, and Ba.

In addition, the method of manufacturing a light emitting device according to the embodiment may include forming a first conductive semiconductor layer on a substrate, forming an active layer on the first conductive semiconductor layer, and forming a second conductive semiconductor layer on the active layer. The second conductive semiconductor layer may be grown under a nitrogen (N ₂ ) gas atmosphere and periodically supply and block hydrogen (H ₂ ) gas during growth of the second conductive semiconductor layer.

In addition, the second conductive semiconductor layer may be an InAlGaN, AlGaN, InGaN, or GaN semiconductor layer doped with impurities, and may include a first layer grown while the hydrogen gas is blocked and a second layer grown while the hydrogen gas is supplied. have.

Hydrogen gas can also selectively etch Ga.

In addition, the second conductive semiconductor layer may have a doping concentration profile including spikes in the form of sharp peaks.

In the light emitting device of the embodiment, the light emission luminance may increase as the concentration of holes increases and the hole diffusion effect is improved.

1 is a cross-sectional view showing a cross section of a light emitting structure included in a light emitting device according to the embodiment;
FIG. 2 illustrates a doping concentration profile of a second conductive semiconductor layer of the light emitting structure of FIG. 1;
3 is a cross-sectional view showing a cross section of a light emitting device according to the embodiment;
4 is a cross-sectional view showing a cross section of a light emitting device according to the embodiment;
5 is a cross-sectional view showing a cross section of a light emitting device package according to the embodiment;
6A is a perspective view illustrating a lighting device including a light emitting device package according to an embodiment;
6B is a cross-sectional view illustrating a cross section along AA ′ of the lighting apparatus of FIG. 5A;
7 is an exploded perspective view of a liquid crystal display device including the optical sheet according to the embodiment, and
8 is an exploded perspective view of a liquid crystal display including the optical sheet according to the embodiment.

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

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

1 is a cross-sectional view showing a cross-section of a light emitting structure included in the light emitting device according to the embodiment, Figure 2 is a view showing a doping concentration profile of the second conductive semiconductor layer of the light emitting structure of FIG.

Referring to FIG. 1, the light emitting structure 100 may include a first conductive semiconductor layer 110, an active layer 120, and a second conductive semiconductor layer 130, and the second conductive semiconductor layer 130 may alternate with each other. The first layer 131 and the second layer 132 on the first layer 131 may be stacked.

First, the first conductive semiconductor layer 110 may be implemented as an n-type semiconductor layer to provide electrons to the active layer 120. A first semiconductor material having a composition formula of the conductive semiconductor layer 110 is _{In x Al y Ga 1 -x- y} N (0 = x = 1, 0 = y = 1, 0 = x + y = 1), e. For example, it may be selected from GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, and the like, and an n-type dopant such as Si, Ge, Sn, or the like may be doped.

In addition, an undoped semiconductor layer (not shown) may be further included under the first conductive semiconductor layer 110, but embodiments are not limited thereto. The undoped semiconductor layer is a layer formed to improve the crystallinity of the first conductive semiconductor layer 110, except that the n-type dopant is not doped and thus has lower electrical conductivity than the first conductive semiconductor layer 110. It may be the same as the first conductive semiconductor layer 110.

The active layer 120 is a region where electrons and holes are recombined. The active layer 120 transitions to a low energy level as the electrons and holes recombine, and may generate light having a corresponding wavelength.

Active well 120 having a compositional formula of In this case, formed of a quantum well structure, for _{example, In x Al y Ga 1 -x-} y N (0 = x = 1, 0 = y = 1, 0 = x + y = 1) It may have a single or quantum well structure having a layer and a barrier layer having a compositional formula of In _a Al _b Ga _{1 -a- b} N (0 = a = 1, 0 = b = 1, 0 = a + b = 1). have. The well layer may be formed of a material having a lower band gap than the band gap of the barrier layer. Therefore, more electrons are collected at the low energy level of the quantum well layer, and as a result, the probability of recombination of electrons and holes can be increased, thereby improving the luminous effect. In addition, a quantum wire structure or a quantum dot structure may be included.

A second semiconductor material having a composition formula of the conductive semiconductor layer 130 is _{In x Al y Ga 1 -x- y} N (0 = x = 1, 0 = y = 1, 0 = x + y = 1), e. For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, etc. may be selected, and doped with a p-type dopant such as Mg, Zn, Ca, Sr, Ba, etc. are implemented as a p-type semiconductor layer to hole in the active layer 120 Can be injected.

According to an embodiment, the second conductive semiconductor layer 130 may include a first layer 131 alternately stacked and a second layer 132 on the first layer 131. 131 and the second layer 132 may be stacked alternately at least twice alternately with each other. In addition, the doping concentration of the impurity of the second layer 132 may be greater than the doping concentration of the impurity of the first layer 131.

As such, since the first layer 131 and the second layer 132 having different doping concentrations are repeatedly formed, the deterioration of crystallinity due to excessive injection of impurities in the process of forming the second conductive semiconductor layer 130 is minimized. can do.

In addition, in the second layer 132 having a relatively high doping concentration, a potential well due to a strong electric field due to impurities may be formed, and a high concentration hole layer may be formed in the potential well to provide holes rich in the active layer 120. Since the first layer 131 having a relatively low doping concentration has a large specific resistance, it is possible to provide uniform holes into the active layer 120 due to the diffusion of holes, and the second layer 132. By being located close to the active layer 120, the mobility of holes can be improved.

The first layer 131 and the second layer 132 may be formed by repeatedly blocking and supplying a hydrogen (H ₂ ) gas when the second conductive semiconductor layer 130 is formed.

For example, the second conductive semiconductor layer 130 may be grown as a p-GaN layer or a p-AlGaN layer in a p-type doping atmosphere, wherein the first layer 131 is grown in a nitrogen (N ₂ ) gas atmosphere. The second layer 132 may be grown by further injecting hydrogen (H 2) gas.

The hydrogen (H ₂ ) gas has a higher etching effect than the nitrogen (N ₂ ) gas, and the hydrogen (H 2) gas supplied during the growth of the second layer 132 selectively etches gallium (Ga). Accordingly, in the second layer 132, relatively more impurities, such as Mg, may remain in the crystal structure than the first layer 131.

Therefore, according to the embodiment, the first layer 131 and the second layer 132 having different doping concentrations of impurities are easily blocked by repeatedly blocking and supplying hydrogen (H ₂ ) gas when forming the second conductive semiconductor layer 130. ) Can be formed.

FIG. 2 illustrates a doping concentration profile of the second conductive semiconductor layer 130 of the light emitting structure 100 of FIG. 1.

Referring to FIG. 2, when the second layer 132 is grown, hydrogen (H ₂ ) gas is additionally supplied, and the hydrogen (H ₂ ) gas is selectively etched Ga at the same time as supplying the second conductive semiconductor. Layer 130 may have a doping concentration profile that includes spikes in the form of pointed peaks. Accordingly, the first layer 131 may include a relatively large amount of Ga, and the crystallinity may be improved compared to the second layer 132.

In addition, since hydrogen (H ₂ ) gas is supplied during the growth of the second layer 132 and is blocked during the growth of the first layer 131, the interface between the first layer 131 and the second layer 132. The doping concentration of the impurities at the odd-numbered interface may be greater than the doping concentration of the impurities at the even-numbered interface.

The hydrogen (H ₂ ) gas may be repeatedly supplied and interrupted at regular intervals. In particular, the supply time of the hydrogen (H ₂ ) gas may be 10 seconds to 30 seconds per time, preferably 15 seconds to 20 seconds per time. The supply and blocking of the hydrogen (H ₂ ) gas as described above may be preferably repeated 10 to 15 times. By repeatedly supplying and blocking hydrogen (H ₂ ) gas as described above, an effect of delta doping of impurities such as Mg can be obtained.

The first conductive semiconductor layer 110, the active layer 120, and the second conductive semiconductor layer 130 described above may be, for example, metal organic chemical vapor deposition (MOCVD) or chemical vapor deposition (CVD). Deposition), Plasma-Enhanced Chemical Vapor Deposition (PECVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), and the like. It is not limited thereto.

In addition, a third conductive semiconductor layer (not shown) including an n-type or p-type semiconductor layer may be formed on the second conductive semiconductor layer 130. Accordingly, the light emitting structure 100 may have np, pn, npn. , pnp junction structure.

In addition, the doping concentrations of the conductive dopants in the first conductive semiconductor layer 110 and the second conductive semiconductor layer 130 may be uniformly or non-uniformly formed. That is, the structure of the plurality of semiconductor layers may be variously formed, but is not limited thereto.

3 is a cross-sectional view showing a cross section of a light emitting device according to the embodiment.

The light emitting device 200 according to the embodiment may include a substrate 210, a light emitting structure 100 on the substrate 210, a light transmitting electrode layer 240 on the light emitting structure 100, and the light emitting structure 100. A portion of the upper surface of the first conductive semiconductor layer 110 may be exposed, and may include a first electrode 260 positioned on the exposed upper surface and a second electrode 250 on the transparent electrode layer 240. The light emitting structure 100 is the same as shown and described with reference to FIGS. 1 and 2, and thus will not be repeated.

The substrate 210 may be formed of a material having a light transmitting property, for example, any one of sapphire (Al ₂ O ₃ ), GaN, ZnO, and AlO, but is not limited thereto. In addition, the SiC substrate may be more thermally conductive than the sapphire (Al ₂ O ₃ ) substrate.

Although not shown, a buffer layer (not shown) that mitigates lattice mismatch between the substrate 210 and the first conductive semiconductor layer 110 may be positioned on the substrate 210. The buffer layer (not shown) may be grown on the substrate 210 as a single crystal, and the buffer layer (not shown) grown as the single crystal may improve the crystallinity of the first conductive semiconductor layer 110 growing on the buffer layer (not shown). Can be.

The buffer layer (not shown) may be formed using a compound semiconductor of Group III-Group 5 elements, and the buffer layer may reduce the difference in lattice constant from the substrate.

Meanwhile, a portion of the active layer 120 and the second conductive semiconductor layer 130 are removed to expose a portion of the first conductive semiconductor layer 110, and titanium is disposed on the exposed upper surface of the first conductive semiconductor layer 110. The first electrode 260 may be formed.

In addition, a transparent electrode layer 240 may be formed on the second conductive semiconductor layer 130, and a second electrode 250 made of nickel (Ni) may be formed on an outer surface of the transparent electrode layer 240.

The transparent electrode layer 240 includes ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrOx, RuOx, RuOx At least one of / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO may be formed and formed on the entire outer surface of the second conductive semiconductor layer 130 to prevent current grouping. have.

4 is a cross-sectional view showing a cross section of a light emitting device according to the embodiment.

Referring to FIG. 4, the light emitting device 300 according to the embodiment includes a support substrate 310, a light emitting structure positioned on the ohmic layer 312 and the ohmic layer 312 on the first surface of the support substrate 310. 100, the light emitting structure 100 may include a first conductive semiconductor layer 110, a second conductive semiconductor layer 130, and a first conductive semiconductor layer 110 and a second conductive semiconductor layer 130. The active layer 120 may be provided on the second conductive semiconductor layer 130. In addition, the second conductive semiconductor layer 130 may be formed by stacking several layers having different doping concentrations of impurities. The light emitting structure 100 is the same as shown and described with reference to FIGS. 1 and 2, and thus will not be repeated.

The support substrate 310 may be formed using a material having excellent thermal conductivity, and may be formed of a conductive material, and may be formed using a metal material or a conductive ceramic. The support substrate 310 may be formed of a single layer and may be formed of a dual structure or multiple structures.

That is, the support substrate 310 may be formed of any one selected from, for example, Au, Ni, W, Mo, Cu, Al, Ta, Ag, Pt, and Cr, or may be formed of two or more alloys. Can be formed by laminating.

The ohmic layer 312 may be used in the form of at least one of ITO, AZO, IZO, Ag, Pt, Ni, Au, Rh, Pd, or an alloy thereof, and the ohmic layer 312 and the supporting substrate 310 by an adhesive layer. May be attached to the light emitting structure 100. The adhesive layer may be a high temperature polymer adhesive so as to maintain adhesiveness in a spin on glass (SOG) or a high temperature atmosphere and not to melt.

Although not shown in the drawings, a reflective film (not shown) may be positioned between the ohmic layer 312 and the support substrate 310, and the reflective film (not shown) is one of light generated in the active layer 120 of the light emitting structure 100. When a part is directed to the support substrate 310, the light extraction efficiency of the light emitting device 300 may be improved by reflecting the light toward the upper portion of the light emitting device 300.

On the other hand, the light emitting device 300 according to the embodiment may include a third electrode 350 on the first conductive semiconductor layer 110, the support substrate 310 facing the first surface of the support substrate 310 The fourth surface 370 may be included on the second surface of the substrate. That is, the third electrode 350 and the fourth electrode 370 may be positioned to face each other.

In addition, the light emitting device 300 may include a concave-convex structure on an upper surface of the first conductive semiconductor layer 110 to improve light extraction efficiency, and include a protective layer 340 on the side surface of the light emitting structure 100. have.

The uneven structure may be formed by a predetermined etching method on a portion of the surface of the first conductive semiconductor layer 110 or the entire region, and the protective layer 340 may be formed of silicon oxide (SiO ₂ ) or silicon nitride (Si ₃ N _4). It can be formed using an insulating material such as).

5 is a cross-sectional view showing a cross section of a light emitting device package according to the embodiment.

Referring to FIG. 5, the light emitting device package 400 according to the embodiment includes a body 410 forming a cavity, a first electrode layer 431 and a second electrode layer 432 provided on the body 410, and a first electrode layer ( The light emitting device 420 electrically connected to the second electrode layer 432 and the resin layer 440 filled in the cavity may be included.

The body 410 is made of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), photosensitive glass (PSG), polyamide 9T (PA9T) ), Neo geotactic polystyrene (SPS), a metal material, sapphire (Al ₂ O ₃ ), beryllium oxide (BeO) may be formed of at least one of a printed circuit board (PCB, Printed Circuit Board).

In addition, the body 410 may include a bottom portion and a wall portion to form a cavity, and the bottom portion and the wall portion may be integrally formed by injection molding, an etching process, and the like, but are not limited thereto. An inner surface of the wall portion may be formed with an inclined surface, and in particular, an angle formed between the side surface of the wall portion forming the cavity and the top surface of the bottom portion may exceed 90 degrees.

On the other hand, the shape viewed from the top of the body 410 may be a shape of a circle, a square, a polygon, an elliptical shape, etc., but may be a curved shape of the corner, but is not limited thereto.

The light emitting device 420 may be, for example, a colored light emitting device emitting light of red, green, blue, white, or the like, or an ultraviolet (Ultra Violet) light emitting device emitting ultraviolet light, but is not limited thereto. In addition, two or more light emitting devices 420 may be mounted in the body 410 at the same time.

In addition, the light emitting device 420 is a horizontal type in which all of its electrical terminals are located on the upper surface as shown and described with reference to FIG. 3, or the upper and lower electrical terminals as shown and described with reference to FIG. 4. Applicable to both vertical type located on the surface.

In FIG. 5, the light emitting device 420 is disposed on the second electrode 532, and is connected to the first electrode layer 431 and the second electrode layer 432 by a wire method, but is not limited thereto. Or it may be electrically connected by any one of the die bonding scheme.

The first electrode layer 431 and the second electrode layer 432 are electrically separated from each other, and supply power to the light emitting device 420. In addition, the first electrode layer 431 and the second electrode layer 432 may increase the light efficiency by reflecting the light generated from the light emitting device 420, and the heat generated from the light emitting device 420 to the outside Can be.

The first electrode layer 431 and the second electrode layer 432 are made of a metal material, for example, titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chromium (Cr), and tantalum (Ta). ), Platinum (Pt), tin (Sn), silver (Ag), phosphorus (P), aluminum (Al), indium (In), palladium (Pd), cobalt (Co), silicon (Si), germanium (Ge) ), Hafnium (Hf), ruthenium (Ru), iron (Fe) may include one or more materials or alloys. In addition, the first electrode layer 431 and the second electrode layer 432 may be formed to have a single layer or a multilayer structure.

The resin layer 440 may be filled in the cavity to cover the light emitting device 420. The resin layer 440 may be formed of silicon, epoxy, and other resin materials, and may be formed by filling in a cavity and then UV or thermosetting it.

On the other hand, the resin layer 440 may include a phosphor 450. The phosphor 450 may be selected according to the wavelength of light generated by the light emitting device 420 so that the light emitting device package may realize white light.

In addition, the phosphor 450 may be disposed in the form of a conformal coating on the upper surface of the light emitting device 420 or the upper surface of the body 410.

The phosphor 450 may be excited by light having a first light emitted from the light emitting element 420 to generate a second light. For example, the light emitting element 420 is a blue light emitting element and the phosphor is yellow. In the case of the phosphor, the yellow phosphor may be excited by blue light to emit yellow light. As the yellow light generated by the blue light and blue light generated by the blue light emitting device is mixed, the light emitting device package 400 may be white. Can provide light.

Similarly, when the light emitting device 420 is a green light emitting device, a magenta phosphor or a mixture of blue and red phosphors is mixed. When the light emitting device 420 is a red light emitting device, a cyan phosphor or a blue and green phosphor is used. For example,

The phosphor 450 may be a known phosphor 450 such as YAG, TAG, sulfide, silicate, aluminate, nitride, carbide, nitridosilicate, borate, fluoride, or phosphate. Can be.

A plurality of light emitting device packages 400 according to the embodiment may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, or the like, which is an optical member, may be disposed on an optical path of the light emitting device package 400. The light emitting device package 400, the substrate, and the optical member may function as a backlight unit or as a lighting unit. For example, the lighting system may include a backlight unit, a lighting unit, an indicator device, a lamp, and a street lamp. .

6A is a perspective view illustrating a lighting device including a light emitting device package according to an embodiment, and FIG. 6B is a cross-sectional view illustrating a C-C 'cross section of the lighting device of FIG. 6A.

Hereinafter, in order to describe the shape of the lighting device 500 according to the embodiment in more detail, the longitudinal direction (Z) of the lighting device 500, the horizontal direction (Y) perpendicular to the longitudinal direction (Z), and the length The height direction X perpendicular to the direction Z and the horizontal direction Y will be described.

That is, FIG. 6B is a cross-sectional view of the lighting apparatus 500 of FIG. 6A cut in the plane of the longitudinal direction Z and the height direction X, and viewed in the horizontal direction Y. As shown in FIG.

6A and 6B, the lighting device 500 may include a body 510, a cover 530 fastened to the body 510, and a closing cap 550 located at both ends of the body 510. have.

The light emitting device module 540 is fastened to the lower surface of the body 510, and the body 510 is conductive so that heat generated in the light emitting device package 544 can be discharged to the outside through the upper surface of the body 510. And it may be formed of a metal material having an excellent heat dissipation effect.

The light emitting device package 544 may be mounted on the PCB 542 in multiple colors and in multiple rows to form an array. The light emitting device package 544 may be mounted at the same interval or may be mounted with various separation distances as necessary to adjust brightness. As the PCB 542, a metal core PCB (MPPCB) or a PCB made of FR4 may be used.

In particular, the light emitting device package 544 according to the embodiment includes a light emitting device (not shown) in which the concentration of holes is increased, and the light emitting device module 540 may be implemented to increase light emission brightness and improve light emission efficiency.

The cover 530 may be formed in a circular shape to surround the lower surface of the body 510, but is not limited thereto.

The cover 530 protects the internal light emitting device module 540 from external foreign matters. In addition, the cover 530 may include diffusing particles to prevent glare of the light generated from the light emitting device package 544 and to uniformly emit light to the outside, and may also include at least one of an inner surface and an outer surface of the cover 530. A prism pattern or the like may be formed on either side. In addition, a phosphor may be applied to at least one of an inner surface and an outer surface of the cover 530.

On the other hand, since the light generated from the light emitting device package 544 is emitted to the outside through the cover 530, the cover 530 should have excellent light transmittance, and has sufficient heat resistance to withstand the heat generated from the light emitting device package 544. The cover 530 is preferably formed of a material containing polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), or the like. .

The closing cap 550 is located at both ends of the body 510 and may be used for sealing a power supply (not shown). In addition, the closing cap 550 is formed with a power pin 552, the lighting device 500 according to the embodiment can be used immediately without a separate device in the terminal from which the existing fluorescent lamps are removed.

7 is an exploded perspective view of a liquid crystal display including the optical sheet according to the embodiment.

7 is an edge-light method, the liquid crystal display 600 may include a liquid crystal display panel 610 and a backlight unit 670 for providing light to the liquid crystal display panel 610.

The liquid crystal display panel 610 may display an image using light provided from the backlight unit 670. The liquid crystal display panel 610 may include a color filter substrate 612 and a thin film transistor substrate 614 facing each other with a liquid crystal interposed therebetween.

The color filter substrate 612 may implement a color of an image displayed through the liquid crystal display panel 610.

The thin film transistor substrate 614 is electrically connected to the printed circuit board 618 on which a plurality of circuit components are mounted through the driving film 617. The thin film transistor substrate 614 may apply the driving voltage provided from the printed circuit board 618 to the liquid crystal in response to the driving signal provided from the printed circuit board 618.

The thin film transistor substrate 614 may include a thin film transistor and a pixel electrode formed of a thin film on another transparent material such as glass or plastic.

The backlight unit 670 may include a light emitting device module 620 for outputting light, a light guide plate 630 for changing the light provided from the light emitting device module 620 into a surface light source, and providing the light to the liquid crystal display panel 610. Reflective sheet for reflecting the light emitted to the light guide plate 630 to the plurality of films 650, 666, 664 and the light guide plate 630 to uniform the luminance distribution of the light provided from the 630 and improve the vertical incidence ( 640).

The light emitting device module 620 may include a PCB substrate 622 such that a plurality of light emitting device packages 624 and a plurality of light emitting device packages 624 are mounted to form an array.

In particular, the light emitting device package 624 according to the embodiment may include a light emitting device (not shown) having an increased concentration of holes, and may implement a backlight unit 670 having an increased light emission luminance and improved light emission efficiency.

Meanwhile, the backlight unit 670 may include a diffusion film 666 for diffusing light incident from the light guide plate 630 toward the liquid crystal display panel 610, and a prism film 650 for condensing the diffused light to improve vertical incidence. ) And a protective film 664 for protecting the prism film 650.

8 is an exploded perspective view of a liquid crystal display including the optical sheet according to the embodiment. However, the parts shown and described in FIG. 7 will not be repeatedly described in detail.

8, the liquid crystal display 700 may include a liquid crystal display panel 710 and a backlight unit 770 for providing light to the liquid crystal display panel 710.

Since the liquid crystal display panel 710 is the same as that described with reference to FIG. 7, a detailed description thereof will be omitted.

The backlight unit 770 includes a plurality of light emitting device modules 723, a reflective sheet 724, a lower chassis 730 in which the light emitting device modules 723 and the reflective sheet 724 are accommodated, and an upper portion of the light emitting device module 723. It may include a diffusion plate 740 and a plurality of optical film 760 disposed in the.

LED Module 723 A plurality of light emitting device packages 722 and a plurality of light emitting device packages 722 may be mounted to include a PCB substrate 721 to form an array.

In particular, the light emitting device package 722 according to the embodiment includes a light emitting device (not shown) having an increased concentration of holes, and can implement a backlight unit 770 with increased light emission luminance and improved light emission efficiency.

The reflective sheet 724 reflects the light generated from the light emitting device package 722 in the direction in which the liquid crystal display panel 710 is positioned to improve light utilization efficiency.

Meanwhile, light generated by the light emitting device module 723 is incident on the diffuser plate 740, and the optical film 760 is disposed on the diffuser plate 740. The optical film 760 includes a diffusing film 766, a prism film 750, and a protective film 764.

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 should be understood that various modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

100: light emitting structure 110: first conductive semiconductor layer
120: active layer 130: second conductive semiconductor layer
131: first layer 132: second layer
200, 300: light emitting element
400: light emitting device package

Claims (16)

Board; And
And a light emitting structure on the substrate, the light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer.
The second conductive semiconductor layer includes a first layer and a second layer on the first layer, wherein the first layer and the second layer are alternately stacked at least twice alternately with each other,
A light emitting device in which the impurity doping concentration of the second layer is greater than the impurity doping concentration of the first layer. The method of claim 1,
The light emitting device of claim 1, wherein a doping concentration of an impurity at an odd-numbered interface among the interfaces between the first layer and the second layer is greater than a doping concentration of the impurity at an even-numbered interface. The method of claim 1,
The second conductive semiconductor layer is an InAlGaN, AlGaN, InGaN or GaN semiconductor layer light emitting device. The method of claim 1,
The light emitting element in which Ga content of a said 1st layer is larger than Ga content of a said 2nd layer. The method of claim 1,
The impurities include at least one of Mg, Zn, Ca, Sr, Ba. The method of claim 1,
A light emitting device comprising a first electrode pad exposed at a portion of an upper surface of the first conductive semiconductor layer and positioned on the exposed upper surface. The method of claim 1,
A light emitting device comprising a light transmitting electrode layer on the second conductive semiconductor layer, and a second electrode on the light transmitting electrode layer. The method of claim 1,
And a second electrode electrically contacting the first conductive semiconductor layer and a second electrode electrically contacting the second conductive semiconductor layer, wherein the first electrode and the second electrode are positioned to face each other. The method of claim 8,
An upper surface of the first conductive semiconductor layer forms an uneven structure, and includes a protective layer on the side of the light emitting structure. Forming a first conductive semiconductor layer on the substrate;
Forming an active layer on the first conductive semiconductor layer; And
Forming a second conductive semiconductor layer on the active layer;
The second conductive semiconductor layer is grown in a nitrogen (N ₂ ) gas atmosphere, the method of manufacturing a light emitting device to periodically supply and block hydrogen (H ₂ ) gas during the growth of the second conductive semiconductor layer. The method of claim 10,
The second conductive semiconductor layer is a light emitting device manufacturing method is an InAlGaN, AlGaN, InGaN or GaN semiconductor layer doped with impurities The method of claim 11,
The second conductive semiconductor layer includes a first layer growing while the hydrogen gas is blocked and a second layer growing while the hydrogen gas is supplied. The method of claim 12,
The hydrogen gas is a light emitting device manufacturing method for selectively etching Ga. The method of claim 12,
The second conductive semiconductor layer is a light emitting device manufacturing method having a doping concentration profile comprising a spike portion of the pointed peak shape. The method of claim 12,
And a doping concentration of the impurities in the second layer is greater than a doping concentration of the impurities in the first layer. The method of claim 11,
The impurity is a light emitting device manufacturing method comprising at least one of Mg, Zn, Ca, Sr, Ba.

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