KR101911865B1 - Light emitting device - Google Patents

Abstract

A light emitting device according to an embodiment includes a light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer; A second electrode layer located in the direction of the second conductivity type semiconductor layer of the light emitting structure and electrically connected to the second conductivity type semiconductor layer; A main electrode disposed on one surface of the second electrode layer in a direction opposite to the second conductivity type semiconductor layer; a second electrode layer branched from the main electrode and penetrating through the second electrode layer, the second conductivity type semiconductor layer, A first bottom electrode including at least one branch electrode electrically connected to the one conductivity type semiconductor layer; At least one first top electrode positioned on the first conductive semiconductor layer; And a first insulating layer disposed between the first bottom electrode and the second electrode layer and between the first bottom electrode and the light emitting structure.

Description

[0001] LIGHT EMITTING DEVICE [0002]

An embodiment relates to a light emitting element.

BACKGROUND ART Light emitting devices such as a light emitting diode (LD) or a laser diode using semiconductor materials of Group 3-5 or 2-6 group semiconductors are widely used for various colors such as red, green, blue, and ultraviolet And it is possible to realize white light rays with high efficiency by using fluorescent materials or colors, and it is possible to realize low energy consumption, semi-permanent life time, quick response speed, safety and environment friendliness compared to conventional light sources such as fluorescent lamps and incandescent lamps .

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

The light emitting device based on the silicon substrate has a higher price competitiveness than the conventional sapphire based structure, but the n-GaN semiconductor layer is formed by the melt-back at the interface between the silicon substrate and the nitride semiconductor layer (GaN) It is difficult to realize a high doping concentration. In addition, it is difficult to grow a sufficient thickness of the n-GaN semiconductor layer on the silicon substrate due to stress due to the difference in lattice mismatching and thermal expansion coefficient between the silicon substrate and the nitride semiconductor layer, this causes the R _th is high, the driving voltage of the light emitting element is formed in the n-type high current density at the electrode neighborhood (current crowding) phenomenon is generated.

Therefore, it is necessary to improve the efficiency of current injection into the light emitting device by improving the current crowding phenomenon in the electrode adjacent portion.

The embodiment attempts to improve the luminous efficiency of the light emitting device.

A light emitting device according to an embodiment includes a light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer; A second electrode layer located in the direction of the second conductivity type semiconductor layer of the light emitting structure and electrically connected to the second conductivity type semiconductor layer; A main electrode disposed on one surface of the second electrode layer in a direction opposite to the second conductivity type semiconductor layer; a second electrode layer branched from the main electrode and penetrating through the second electrode layer, the second conductivity type semiconductor layer, A first bottom electrode including at least one branch electrode electrically connected to the one conductivity type semiconductor layer; At least one first top electrode positioned on the first conductive semiconductor layer; And a first insulating layer disposed between the first bottom electrode and the second electrode layer and between the first bottom electrode and the light emitting structure.

Wherein the first conductivity type semiconductor layer includes a first region corresponding to an upper portion of a branch electrode of the first bottom electrode and a second region corresponding to a lower portion of the first top electrode, The second region may be non-overlapping.

The branch electrode of the first bottom electrode may have a width of 10 [mu] m to 100 [mu] m.

The branch electrode of the first bottom electrode may be spaced from the neighboring branch electrode by an interval of 20 [mu] m to 500 [mu] m.

The first top electrode may have a width of between 5 um and 100 um.

The branch electrode of the first bottom electrode and the first top electrode may be separated by a horizontal distance of 10 [mu] m to 500 [mu] m.

A roughness pattern may be located on the surface of the first conductivity type semiconductor layer.

At least a part of the second electrode layer may be exposed to the outside of the light emitting structure, and the electrode pad may be located on the exposed second electrode layer.

The second electrode layer may include at least one of an ohmic layer and a reflective layer.

And a second insulating layer surrounding the side surface of the light emitting structure.

And a supporting substrate positioned adjacent to the main electrode of the first bottom electrode.

The first top electrode may be spaced from the neighboring first top electrode by an interval of 10 um to 500 um.

The branch electrode of the first bottom electrode and the first top electrode may be spaced apart from each other with at least a part of the first conductivity type semiconductor layer interposed therebetween.

According to the embodiment, the first bottom electrode and the first top electrode are positioned in both directions of the first conductivity type semiconductor layer to improve current density and current injection efficiency, thereby improving the luminous efficiency of the light emitting device .

1 is a side cross-sectional view of a light emitting device according to an embodiment,
FIGS. 2 to 8 are views illustrating a manufacturing process of a light emitting device according to an embodiment,
9 is an image profile of a light emitting device that shows the intensity of light emitted when only the first bottom electrode exists and when the first bottom electrode and the first top electrode are present together,
10 is a view illustrating a light emitting device package including a light emitting device according to an embodiment,
11 is a view showing an embodiment of a headlamp in which the light emitting device according to the embodiment is disposed,
12 is a diagram illustrating a display device in which a light emitting device package according to an embodiment is disposed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

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.

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

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

A light emitting device 100 according to an exemplary embodiment includes a light emitting structure 110 including a first conductive semiconductor layer 112, an active layer 114, and a second conductive semiconductor layer 116; A second electrode layer 140 located in the direction of the second conductivity type semiconductor layer 116 of the light emitting structure 110 and electrically connected to the second conductivity type semiconductor layer 116; The main electrode 120a located on one side of the second electrode layer 140 and the second electrode layer 140 branched from the main electrode 120a and the second conductivity type semiconductor layer 116 and the active layer 114 A first bottom electrode 120 including at least one branch electrode 120b electrically connected to the first conductivity type semiconductor layer 112 through the first bottom electrode 120; At least one first top electrode (130) located on the first conductive semiconductor layer (112); And a first insulating layer 150 between the first bottom electrode 120 and the second electrode layer 140 and between the first bottom electrode 120 and the light emitting structure 110.

The light emitting device 100 includes an LED (Light Emitting Diode) using a semiconductor layer of a plurality of compound semiconductor layers, for example, a group III-V element, and the LED is a coloring material that emits light such as blue, green, LED or UV LED. The emitted light of the LED may be implemented using various semiconductors, but is not limited thereto.

The light-emitting structure 110 may be formed by, for example, metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD) (MBE), hydride vapor phase epitaxy (HVPE), or the like, but the present invention is not limited thereto.

The first conductive semiconductor layer 112 may be formed of a semiconductor compound, for example, a compound semiconductor such as a group III-V element or a group II-VI element. The first conductive type dopant may also be doped. When the first conductive semiconductor layer 112 is an n-type semiconductor layer, the first conductive dopant may include Si, Ge, Sn, Se, Te, or the like as the n-type dopant, but is not limited thereto. In addition, when the first conductive semiconductor layer 112 is a p-type semiconductor layer, the first conductive dopant may include Mg, Zn, Ca, Sr, and Ba as a p-type dopant, but is not limited thereto .

The first conductive semiconductor layer 112 includes a semiconductor material having a composition formula of Al _x In _y Ga _(1-xy) N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) can do. The first conductive semiconductor layer 112 may be formed of one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP and InP.

A roughness pattern 180 may be formed on the surface of the first conductivity type semiconductor layer 112 to improve light extraction efficiency. The roughness pattern 180 may be formed by a dry etching process or a wet etching process.

The second conductive semiconductor layer 116 may be formed of a semiconductor compound, for example, a group III-V compound semiconductor doped with a second conductive dopant. The second conductivity type semiconductor layer 116 has a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) Semiconductor material. When the second conductive semiconductor layer 116 is a p-type semiconductor layer, the second conductive dopant may include Mg, Zn, Ca, Sr, and Ba as p-type dopants, but is not limited thereto. When the second conductivity type semiconductor layer 116 is an n-type semiconductor layer, the second conductivity type dopant may include Si, Ge, Sn, Se, and Te as n-type dopants, but is not limited thereto .

In the present embodiment, the first conductive semiconductor layer 112 may be an n-type semiconductor layer, and the second conductive semiconductor layer 116 may be a p-type semiconductor layer. Alternatively, the first conductivity type semiconductor layer 112 may be a p-type semiconductor layer, and the second conductivity type semiconductor layer 116 may be an n-type semiconductor layer. Also, an n-type semiconductor layer (not shown) may be formed on the second conductive semiconductor layer 116 if the semiconductor having the opposite polarity to the second conductive type, for example, the second conductive semiconductor layer is a p-type semiconductor layer . Accordingly, the light emitting structure may have any one of an n-p junction structure, a p-n junction structure, an n-p-n junction structure, and a p-n-p junction structure.

The active layer 114 is positioned between the first conductive semiconductor layer 112 and the second conductive semiconductor layer 116.

The active layer 114 is a layer in which electrons and holes meet each other to emit light having energy determined by the energy band inherent in the active layer (light emitting layer) material. When the first conductivity type semiconductor layer 112 is an n-type semiconductor layer and the second conductivity type semiconductor layer 116 is a p-type semiconductor layer, electrons are injected from the first conductivity type semiconductor layer 112, A hole can be injected from the conductive type semiconductor layer 116.

The active layer 114 may be formed of at least one of a single well structure, a multi-well structure, a quantum-wire structure, or a quantum dot structure. For example, the active layer 114 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.

InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, GaAs (InGaAs) / AlGaAs, GaP (InGaP), and InGaN / / AlGaP, but the present invention is not limited thereto. The well layer may be formed of a material having a bandgap narrower than the bandgap of the barrier layer.

A conductive clad layer (not shown) may be formed on and / or below the active layer 114. The conductive clad layer may be formed of a semiconductor having a band gap wider than the band gap of the barrier layer of the active layer. For example, the conductive clad layer may comprise GaN, AlGaN, InAlGaN or a superlattice structure. Further, the conductive clad layer may be doped with n-type or p-type.

The second electrode layer 140 is located in the direction of the second conductivity type semiconductor layer 116 of the light emitting structure 110 and the second conductivity type semiconductor layer 116 and the second electrode layer 140 are electrically connected.

The second electrode layer 140 includes a conductive layer 142 having excellent electrical conductivity such that the current injected from the outside can be uniformly distributed horizontally. The conductive layer 142 is formed of, for example, Ti, Au, Ni , In, Co, W, Fe. Rh, Cr, Al, and the like, but is not limited thereto.

The second electrode layer 140 may include an ohmic layer 144 or a reflective layer 146 and may have a stacked structure of an ohmic layer 114 and a reflective layer 146 as shown in FIG.

The ohmic layer 144 may be positioned in contact with the second conductive semiconductor layer 116 of the light emitting structure 110. The second conductivity type semiconductor layer 116 has a low impurity doping concentration and may have a high contact resistance and thus may not have good ohmic characteristics with the metal. For this reason, the ohmic layer 144 must be formed It is not.

The ohmic layer 144 may be made of a transparent conductive layer and a metal. For example, ITO (indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tin oxide), IZO ), IGZO (indium gallium zinc oxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON TiO 2, Ag, Ni, Cr, Ti, Al, Rh, ZnO, IGZO (In-Ga ZnO), ZnO, IrOx, RuOx, NiO, RuOx / ITO, Ni / IrOx / Au, Pd, Ir, Sn, In, Ru, Mg, Zn, Pt, Au, and Hf.

Since the ohmic layer 144 is disposed between the light emitting structure 110 and the reflective layer 146 to be described later, the ohmic layer 144 may be formed of a transparent electrode or the like and may be formed of a layer or a plurality of patterns.

The reflective layer 146 may be positioned on one surface of the ohmic layer 144 that is not in contact with the second conductivity type semiconductor layer 116.

The reflective layer 146 can improve the luminous efficiency of the light emitting device by causing the light generated in the active layer 114 to be reflected without being extinguished inside the light emitting device to be emitted outside the light emitting device 100.

The reflective layer 146 may be formed of a material having a high reflectance and may be formed of a material such as Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Or may be formed in a multi-layer structure using the metal material and a light-transmitting conductive material such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, and ATO. Also, the reflective layer 146 may be formed of a laminated structure of IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / When the reflective layer 146 is formed of a material that makes an ohmic contact with the light emitting structure (for example, the second conductive semiconductor layer 116), the ohmic layer 144 may not be formed separately, .

The support substrate 160 is disposed on one surface of the main electrode 120a of the first bottom electrode 120 as a support for supporting the light emitting structure 110, the second electrode layer 140, and the first bottom electrode 120, do.

The supporting substrate 160 supports the light emitting structure 110 and may be a conductive substrate or an insulating substrate. Further, it can be formed of a material having high electrical conductivity and high thermal conductivity. For example, the support substrate 160 may be a base substrate having a predetermined thickness, and may be a substrate made of molybdenum (Mo), silicon (Si), tungsten (W), copper (Cu) (Au), copper alloy (Cu Alloy), nickel (Ni), copper-tungsten (Cu-W), carrier wafers (e.g., GaN, Si, a Ge, GaAs, ZnO, SiGe, SiC, SiGe, Ga 2 O 3 , etc.) or a conductive sheet or the like may optionally be included.

The bonding layer 165 may be positioned between the supporting substrate 160 and the main electrode 120a. The bonding layer 165 may be formed of a material selected from the group consisting of Au, Sn, In, Ag, Ni, Nb and Cu, or an alloy thereof, but is not limited thereto.

The first bottom electrode 120 includes a main electrode 120a disposed on one side of the second electrode layer 140 in a direction opposite to the second conductivity type semiconductor layer 116 and a second main electrode 120b branched from the main electrode 120a And at least one branch electrode 120b that penetrates the second electrode layer 140, the second conductivity type semiconductor layer 116, and the active layer 114 and contacts the first conductivity type semiconductor layer 112.

At least one first top electrode 130 is disposed on the first conductivity type semiconductor layer 112.

The branch electrode 120b of the first bottom electrode 120 and the first top electrode 130 are spaced apart from each other with at least a part of the first conductivity type semiconductor layer 112 therebetween.

The branch electrode 120b of the first bottom electrode 120 and the first top electrode 130 are formed such that the regions extending in the vertical direction do not overlap each other.

That is, the first region A of the first conductivity type semiconductor layer 112 corresponding to the upper portion of the branch electrode 120b and the second region A of the first conductivity type semiconductor layer corresponding to the lower portion of the first top electrode 130 The regions B are non-overlapping with each other.

The positional relationship between the branch electrode 120b of the first bottom electrode 120 and the first top electrode 130 will be described with reference to a path through which the current flows. 130 are connected to the first path 191 of the current flowing from the second electrode layer 140 to the first bottom electrode 120 and the second path 191 of the current flowing from the second electrode layer 140 to the first top electrode 130. [ (192) are not overlapped.

In the present embodiment, at least one branch electrode 120b and at least one first top electrode 130 are disposed on different sides of the first conductivity type semiconductor layer 112 to disperse a current flowing path, It is possible to improve the current crowding phenomenon and improve the current injection efficiency.

Particularly, when a silicon-based substrate such as Si or SiC is used as a growth substrate, a stress due to a difference in lattice mismatching and a thermal expansion coefficient between the silicon substrate and the first conductivity type semiconductor layer 112, It is difficult to grow the first conductivity type semiconductor layer 112 having a sufficient thickness, so that the surface resistance R _th is high due to the low doping concentration, so that a current is concentrated in the vicinity of the first electrode.

The first path 191 of the current flowing from the second electrode layer 140 to the branch electrode 120b of the first bottom electrode 120 and the first path 191 of the current flowing from the second electrode layer 140 to the first top electrode 130 The current path is evenly distributed throughout the light emitting device as in the case of the second path 192 of the current flowing in the light emitting device.

In one example, the branch electrode 120b of the first bottom electrode 120 may be formed with a width d ₁ of 10 um to 100 um and the first top electrode 130 has a width d ₂ of 5 um to 100 um. As shown in FIG.

If the widths d ₁ and d _{2 of the} branch electrode 120b and the first top electrode 130 are formed too narrow, the effect of improving the current crowding phenomenon may be insignificant. On the other hand, if the width d ₁ of the branch electrode 120b is too wide, the area of the light emitting structure 110 removed by etching increases, If the width d ₂ is formed too wide, the first top electrode 130 may absorb light or interfere with light propagation to the outside.

The branch electrode 120b of the first bottom electrode 120 and the first top electrode 130 may be spaced apart by a horizontal distance d ₃ of 10 to 500 μm.

If the distance d ₃ between the branch electrode 120b and the first top electrode 130 is too narrow, the widths d ₁ and d _{2 of} the branch electrode 120b and the first top electrode 130 are too wide And if the separation distance d ₃ between the branch electrode 120b and the first top electrode 130 is too wide, the effect of improving the current densification phenomenon may be insignificant.

The top electrode of Q1 electrode (120b) of the bottom electrode 120 is spaced apart by a branch electrode (120b) and 20um to 500um distance (d ₄₎ adjacent may be located, the first top electrode 130 adjacent are spaced apart by 130 and 10um to 500um distance (d ₅₎ may be located.

Branch separation distance of the electrodes (120b), (d ₄₎ can be adjusted to the width (d ₂₎ and the number of the first top electrode 130 is positioned between two branch electrode (120b), a first top The spacing d ₅ of the electrodes 130 can be adjusted according to the width d ₁ and the number of the branch electrodes 120b located between the two first top electrodes 130.

The above-described numerical values (d ₁ to d ₅ ) are only examples, and may be changed according to the embodiment.

The branch electrode 120b and the first top electrode 130 of the first bottom electrode 120 may have a radial pattern, a cruciform pattern, a line pattern, a curved pattern, a loop pattern, a ring pattern, Pattern, but it is not limited thereto.

A roughness pattern (not shown) may be formed at a portion of the first bottom electrode 120 where the branch electrode 120b and the first conductivity type semiconductor layer 112 are in contact with each other. Such a roughness pattern can increase the area in which the branch electrode 120b and the first conductivity type semiconductor layer 112 are in contact with each other to improve the electrical characteristics of the light emitting device 100. The branch electrode 120b and the first conductivity- The reliability of the light emitting device 100 can be improved by increasing the adhesion between the semiconductor layers 112.

1, one branch electrode 120b and one first top electrode 130 are alternately arranged. However, the branch electrodes 120b and 120b may be alternately arranged according to an embodiment of the present invention. The number of first top electrodes 130 may vary.

At least a portion of the second electrode layer 140 is exposed to the outside of the light emitting structure 110, and the electrode pad 170 is located at the exposed portion. The electrode pad 170 may be disposed in contact with the conductive layer 142 of the second electrode layer 140.

Although only one electrode pad 170 is shown as an example in FIG. 1, two or more electrode pads 170 may exist according to an embodiment.

The electrode pad 170 is electrically connected to both the first top electrode 130, the first bottom electrode 120 and the second electrode layer 140 to supply a current required for driving the light emitting device.

The first bottom electrode 120 and the first top electrode 130 are formed of a metal selected from Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, Ti, It can be made in an optional combination. In addition, the first bottom electrode 120 and the first top electrode 130 may be formed as a single layer or multiple layers of an electrode material having ohmic characteristics.

The first bottom electrode 120 and the first top electrode 130 may be formed of one selected from the group consisting of ITO (indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tin oxide), IAZO (indium aluminum zinc oxide), IGZO zinc oxide, indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrOx, RuOx, RuOx / ITO, Ni / IrOx / IrOx / Au / ITO, and the material is not limited thereto.

In addition, the first bottom electrode 120 may be formed of a reflective electrode material so as to reflect light generated in the active layer 114 without absorbing the light. The main electrode 120a may include a bonding layer, The bonding layer may include at least one of Ti, Au, Sn, Ni, Cr, Ga, In, Bi, Cu, Ag and Ta.

When the main electrode 120a of the first bottom electrode 120 includes a bonding layer, the bonding layer 165 may not be separately formed.

The first insulating layer 150 is positioned between the first bottom electrode 120 and the second electrode layer 140 and between the first bottom electrode 120 and the light emitting structure 110 to electrically isolate the first insulating layer 150 from the first bottom electrode 120. [

The first insulating layer 150 may be made of a non-conductive oxide or nitride. As an example, the insulating layer 170 may be formed of a silicon oxide (SiO ₂ ) layer, an oxynitride layer, or an aluminum oxide layer.

In addition, the second insulating layer 175 may be positioned to surround the side surface of the light emitting structure 110. The second insulating layer 175 may also be formed of a nonconductive oxide or a nitride. For example, the insulating layer 170 may be formed of a silicon oxide (SiO ₂ ) layer, an oxynitride layer, or an aluminum oxide layer .

FIGS. 2 to 8 are views illustrating a manufacturing process of a light emitting device according to an embodiment. Hereinafter, an embodiment of a method for manufacturing a light emitting device will be described with reference to FIGS. 2 to 8. FIG.

Referring to FIG. 2, a light emitting structure 110 is grown on a substrate 101.

The substrate 101 may be formed of a material suitable for semiconductor material growth, or a carrier wafer. Further, it may be formed of a material having excellent thermal conductivity, and may be a conductive substrate or an insulating substrate. For example, at least one of sapphire (Al ₂ O ₃ ), SiC, GaAs, GaN, ZnO, Si, GaP, InP, Ge, and Ga ₂ O ₃ can be used as the substrate 101. A concave-convex structure may be formed on the substrate 101, but the present invention is not limited thereto. The substrate 101 may be wet-cleaned to remove impurities on the surface.

The light emitting structure 110 may be formed by successively growing a first conductive semiconductor layer 112, an active layer 114, and a second conductive semiconductor layer 116 on a substrate 101.

The light-emitting structure 110 may be formed by, for example, metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD) (MBE), hydride vapor phase epitaxy (HVPE), or the like, but the present invention is not limited thereto.

The template layer 104 can be grown between the light emitting structure 110 and the substrate 101. [

The template layer 104 includes a buffer layer and may further include a stress relief layer depending on the type of the substrate 101. [

The buffer layer is for reducing the difference in lattice mismatch and thermal expansion coefficient between the substrate 101 and the material of the first conductivity type semiconductor layer 112. The buffer layer is made of Group III-V compound semiconductor such as GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN.

The stress relieving layer may include AlN or AlGaN having an Al composition of 50% or more, and may be formed of a single layer of AlN, AlGaN, or a laminated structure of AlN / AlGaN.

Referring to FIG. 3, a second electrode layer 140 is formed on the second conductive semiconductor layer 114.

The second electrode layer 140 may include at least one of an ohmic layer 144 and a reflective layer 146. The conductive layer 142 may include a conductive layer 142 having excellent electrical conductivity so that the current injected from the outside may spread horizontally evenly. .

The second electrode layer 140 may be formed by any one of E-beam deposition, sputtering, and plasma enhanced chemical vapor deposition (PECVD), but the present invention is not limited thereto.

4, at least one via hole (not shown) for exposing the first conductivity type semiconductor layer 112 through the second electrode layer 140, the second conductivity type semiconductor layer 116, and the active layer 114 210 are formed.

The via hole 210 may be formed using, for example, a photolithography process or an etching process. The second electrode layer 140 may be selectively etched to expose the second conductive semiconductor layer 116, The exposed portion of the second conductive semiconductor layer 116 and the active layer 114 under the exposed second conductive semiconductor layer 116 may be etched to expose the first conductive semiconductor layer 112.

5, a first insulating layer 150 is formed on the upper surface of the second electrode layer 140 and at least a part of the side surface and the bottom surface of the via hole 210. Referring to FIG.

The first bottom electrode 120 is formed by filling the via hole 210 with a conductive material and applying a conductive material to cover the upper portion of the second electrode layer 140.

The portion of the conductive material disposed in parallel with the second electrode layer 140 becomes the main electrode 120a of the first bottom electrode 120 and the portion of the conductive material filled in the via hole 210 becomes the branch electrode of the first bottom electrode 120. [ (120b).

The first bottom electrode 120 may be formed of a metal selected from Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, Ti and Cr.

Referring to FIG. 6, the supporting substrate 160 is disposed on the first bottom electrode 120.

The supporting substrate 160 may be formed by a bonding method, a plating method, or a deposition method. When the supporting substrate 160 is formed by a bonding method, the first bottom electrode 120 and the supporting substrate 110 may be attached using a separate bonding layer 165, for example.

Then, as shown in Fig. 7, the substrate 101 is separated.

The substrate 101 may be separated by a laser lift off (LLO) method using an excimer laser or the like, or by dry etching and wet etching.

When excimer laser light having a wavelength in a certain region in the direction of the substrate 101 is focused and irradiated by using the laser lift-off method as an example, heat energy is applied to the interface between the substrate 101 and the light emitting structure 140 The interface is separated into gallium and nitrogen molecules, and the substrate 101 is instantaneously separated from the laser light passing portion. After removing the substrate 101, the template layer 104 may be removed through a separate etching process.

Referring to FIG. 8, the light emitting structure 110 is subjected to isolation etching so as to be separated into the respective light emitting device units. The isolation etching can be performed by, for example, a dry etching method such as ICP (Inductively Coupled Plasma). A part of the second electrode layer 140 may be opened to the outside of the light emitting structure 110 by the isolation etching. For example, the light emitting structure 110 may be etched by isolation etching to open one side of the second electrode layer 140, that is, a part of the rim.

A first top electrode 130 is formed on the first conductive semiconductor layer 112 of the light emitting structure 110.

The first top electrode 130 and the branch electrode 120b of the first bottom electrode 120 are formed so that regions extending in the vertical direction do not overlap with each other.

That is, the first region A of the first conductivity type semiconductor layer 112 corresponding to the upper portion of the branch electrode 120b and the second region A of the first conductivity type semiconductor layer corresponding to the lower portion of the first top electrode 130 The first top electrode 120 is arranged so that the regions B are non-overlapping with each other.

The electrode pad 170 is formed on the exposed portion of the second electrode layer 140 that is opened by the isolation etching.

The electrode pad 170 may be electrically connected to the first top electrode 130, the first branch electrode 120 and the second electrode layer 140 to supply a current required to drive the light emitting device 100.

A second insulating layer 175 is formed to surround the side surface of the light emitting structure 110. The second insulating layer 175 may be formed to cover a portion of the upper surface of the first conductive type semiconductor layer 112.

FIG. 9 is an image profile of a light emitting device that shows the intensity of light emitted when only the first bottom electrode exists and when the first bottom electrode and the first top electrode are present together.

9A shows a case where only the first bottom electrode exists, and the branch electrode of the first bottom electrode is formed in a rectangular loop pattern.

FIG. 9B illustrates a case where the first bottom electrode and the first top electrode exist together according to the embodiment, wherein the inner rectangular loop pattern is the first top electrode and the outer rectangular loop pattern is the first bottom electrode .

When the intensity of the emitted light is represented by a numerical value from 0 to 100 as shown in FIG. 9 (c), when the image profile is close to the purple color (0), when the intensity of the light is weak and when it is close to the red color 100 It can be said that the intensity of light is big.

Referring to FIG. 9, a light emitting device (b) having a first bottom electrode and a first top electrode together with a light emitting device (b) having only a first bottom electrode (a) It can be seen that the intensity of light is greater when the first bottom electrode and the first top electrode are present together according to the embodiment and that the distribution of the color is uniform and the spread of the current is also improved have. The power of the light emitting device also showed a higher value of 550 mW in the case of the embodiment (b).

10 is a view illustrating a light emitting device package including a light emitting device according to an embodiment.

The light emitting device package 300 according to an embodiment includes a body 310, a first lead frame 321 and a second lead frame 322 provided on the body 310, A light emitting device 100 according to the above embodiments electrically connected to the first lead frame 321 and the second lead frame 322 and a molding part 340 formed in the cavity. A cavity may be formed in the body 310.

The body 310 may include 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 separated from each other and supply current to the light emitting device 100. The first lead frame 321 and the second lead frame 322 may increase the light efficiency by reflecting the light generated from the light emitting device 100. The heat generated from the light emitting device 100 To the outside.

The light emitting device 100 may be mounted on the body 310 or may be mounted on the first lead frame 321 or the second lead frame 322. The first lead frame 321 and the light emitting element 100 are directly energized and the second lead frame 322 and the light emitting element 100 are connected to each other through the wire 330 in this embodiment. The light emitting device 100 may be connected to the lead frames 321 and 322 by a flip chip method or a die bonding method in addition to the wire bonding method.

The molding part 340 may surround and protect the light emitting device 100. In addition, the phosphor 350 may be included on the molding part 340 to change the wavelength of light emitted from the light emitting device 100.

The phosphor 350 may include a garnet-based phosphor, a silicate-based phosphor, a nitride-based phosphor, or an oxynitride-based phosphor.

For example, the garnet-base phosphor is _{YAG (Y 3 Al 5 O 12} : Ce 3 +) or TAG: may be a _{(Tb 3 Al 5 O 12 Ce} 3 +), wherein the silicate-based phosphor is (Sr, Ba, Mg, Ca) ₂ SiO ₄ : Eu ^{2 +} , and the nitride phosphor may be CaAlSiN ₃ : Eu ^{2 +} containing SiN, and the oxynitride phosphor may be Si _{6 - x Al x O x N 8 -x:} Eu 2 + (0 <x <6) can be.

The light of the first wavelength range emitted from the light emitting device 100 is excited by the fluorescent material 250 to be converted into the light of the second wavelength range and the light of the second wavelength range passes through the lens (not shown) The light path can be changed.

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, the headlamp and the backlight unit will be described as an embodiment of the lighting system in which the above-described light emitting device or the light emitting device package is disposed.

11 is a view showing an embodiment of a headlamp in which a light emitting device according to an embodiment is disposed.

11, the light emitted from the light emitting module 710 in which the light emitting device according to the embodiment is disposed is reflected by the reflector 720 and the shade 730 and then transmitted through the lens 740 to be directed to the front of the vehicle body have.

The light emitting module 710 may include a plurality of light emitting devices on a circuit board, but the present invention is not limited thereto.

Since the current injection efficiency of the light emitting device according to the embodiment is improved, the light emitting efficiency of the light emitting module 710 can be improved.

12 is a diagram illustrating a display device in which a light emitting device package according to an embodiment is disposed.

12, the display device 800 according to the embodiment includes the light emitting modules 830 and 835, the reflection plate 820 on the bottom cover 810, and the reflection plate 820 disposed on the front side of the reflection plate 820, A first prism sheet 850 and a second prism sheet 860 disposed in front of the light guide plate 840 and a second prism sheet 860 disposed in front of the light guide plate 840, A panel 870 disposed in front of the panel 870 and a color filter 880 disposed in front of the panel 870.

The light emitting module includes the above-described light emitting device package 835 on the circuit board 830. Here, the circuit board 830 may be a PCB or the like, and the light emitting device package 835 is the same as that described with reference to FIG.

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

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

The light guide plate 840 scatters 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 830 is made of a material having a good refractive index and transmittance. The light guide plate 830 may be formed of polymethyl methacrylate (PMMA), polycarbonate (PC), or polyethylene (PE). An air guide system is also available in which the light guide plate is omitted and light is transmitted in a space above the reflective sheet 820.

The first prism sheet 850 is formed on one side of the support film with a transparent and elastic polymeric material, and 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 860, the edges and the valleys on one surface of the support film may be perpendicular to the edges and the valleys on one surface of the support film in the first prism sheet 850. This is to uniformly distribute the light transmitted from the light emitting module and the reflective sheet in all directions of the panel 870.

In the present embodiment, the first prism sheet 850 and the second prism sheet 860 form an optical sheet, which may be formed of other combinations, for example, a microlens array or 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 870. In addition to the liquid crystal display panel 860, other types of display devices requiring a light source may be provided.

In the panel 870, the liquid crystal is positioned between the glass bodies, and the 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 880 is provided on the front surface of the panel 870 so that light projected from the panel 870 transmits only red, green, and blue light for each pixel.

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 embodiments, but, on the contrary, This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

100: light emitting element 101: substrate
104: template layer 110: light emitting structure
112: first conductivity type semiconductor layer 114: active layer
116: second conductivity type semiconductor layer 120: first bottom electrode
120a: main electrode 120b: branch electrode
130: first top electrode 140: second electrode layer
310: package body 321, 322: first and second lead frames
330: wire 340: molding part
350: phosphor 710: light emitting module
720: Reflector 730: Shade
800: Display device 810: Bottom cover
820: reflector 840: light guide plate
850: first prism sheet 860: second prism sheet
870: Panel 880: Color filter

Claims (13)

A light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer;
A second electrode layer located in the direction of the second conductivity type semiconductor layer of the light emitting structure and electrically connected to the second conductivity type semiconductor layer;
A main electrode disposed on one surface of the second electrode layer in a direction opposite to the second conductivity type semiconductor layer; a second electrode layer branched from the main electrode and penetrating through the second electrode layer, the second conductivity type semiconductor layer, A first bottom electrode including at least one branch electrode electrically connected to the one conductivity type semiconductor layer;
At least one first top electrode positioned on the first conductive semiconductor layer; And
And a first insulating layer disposed between the first bottom electrode and the second electrode layer and between the first bottom electrode and the light emitting structure,
Wherein the branch electrode of the first bottom electrode and the first top electrode are spaced apart from each other with at least a part of the first conductivity type semiconductor layer being interposed therebetween. The method according to claim 1,
Wherein the first conductivity type semiconductor layer includes a first region corresponding to an upper portion of a branch electrode of the first bottom electrode and a second region corresponding to a lower portion of the first top electrode, And the second region is non-overlapping. The method according to claim 1,
And the branch electrode of the first bottom electrode has a width of 10 mu m to 100 mu m. The method according to claim 1,
Wherein the branch electrode of the first bottom electrode is spaced apart from the neighboring branch electrode by an interval of 20 to 500 탆. The method according to claim 1,
And the first top electrode has a width of 5 um to 100 um. The method according to claim 1,
Wherein the branch electrode of the first bottom electrode and the first top electrode are separated by a horizontal distance of 10 um to 500 um. The method according to claim 1,
And a roughness pattern is located on the surface of the first conductivity type semiconductor layer. The method according to claim 1,
Wherein at least a part of the second electrode layer is exposed to the outside of the light emitting structure, and the electrode pad is located on the exposed second electrode layer. The method according to claim 1,
Wherein the second electrode layer includes at least one of an ohmic layer and a reflective layer. The method according to claim 1,
And a second insulating layer surrounding a side surface of the light emitting structure. The method according to claim 1,
And a supporting substrate positioned adjacent to the main electrode of the first bottom electrode. The method according to claim 1,
Wherein the first top electrode is spaced apart from the neighboring first top electrode by an interval of 10 um to 500 um. delete

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