KR20130067441A - Light emitting device - Google Patents

Abstract

PURPOSE: A light emitting device is provided to improve the efficiency of light generated in an active layer by reducing the area of light blocked by an electrode. CONSTITUTION: A light emitting structure includes first and second semiconductor layers(120,140) and an active layer(130). A first electrode is electrically connected to the first semiconductor layer. A second electrode is arranged on the second semiconductor layer. A lower surface of the second electrode includes a protrusion part. The protrusion part is formed in the thickness direction of the light emitting structure.

Description

[0001]

An embodiment relates to a light emitting element.

As a typical example of a light emitting device, a light emitting diode (LED) is a device for converting an electric signal into an infrared ray, a visible ray, or a light using the characteristics of a compound semiconductor, and is used for various devices such as household appliances, remote controllers, Automation equipment, and the like, and the use area of LEDs is gradually widening.

In general, miniaturized LEDs are made of a surface mounting device for mounting directly on a PCB (Printed Circuit Board) substrate, and an LED lamp used as a display device is also being developed as a surface mounting device type . Such a surface mount device can replace a conventional simple lighting lamp, which is used for a lighting indicator for various colors, a character indicator, an image indicator, and the like.

As the use area of the LED is widened as described above, it is important to increase the luminance of the LED as the brightness required for a lamp used in daily life and a lamp for a structural signal is increased.

The embodiment provides a light emitting device in which the luminous efficiency is improved.

The light emitting device according to the embodiment includes a first semiconductor layer, a light emitting structure including an active layer between the second semiconductor layer and the first semiconductor layer and the second semiconductor layer, and a first electrode electrically connected to the first semiconductor layer. And a second electrode disposed on the second semiconductor layer, wherein a lower surface of the second electrode includes a protrusion protruding in the thickness direction of the light emitting structure, and an angle formed by the inclined surfaces of the protrusion is 120 degrees to It can be 170 degrees.

The light emitting device according to the embodiment can improve the luminous efficiency of the light emitting device by reducing the area blocking the light generated in the active layer while ensuring the contact area between the second semiconductor layer and the electrode.

In addition, since light is reflected on the inclined surface under the electrode and discharged to the outside, the luminous efficiency of the light emitting device can be improved.

1 is a perspective view showing a light emitting device according to an embodiment.
2 is a plan view illustrating the light emitting device of FIG. 1.
3 is a cross-sectional view taken along line AA of the light emitting device of FIG. 1.
FIG. 4 is an enlarged view illustrating region a of FIG. 3.
5 is a cross-sectional view illustrating an electrode according to another embodiment.
6 is an explanatory diagram illustrating a light traveling path of a light emitting device according to an embodiment.
7 is a cross-sectional view showing a light emitting device according to another embodiment.
8 is a plan view illustrating a light emitting device according to yet another embodiment.
FIG. 9 is a view illustrating a BB cross section of the light emitting device of FIG. 8.
10 is a cross-sectional view illustrating a light emitting device according to yet another embodiment.
11 to 15 are flowcharts illustrating a method of manufacturing a light emitting device according to the embodiment.
16 is a perspective view showing a light emitting device package including a light emitting device according to the embodiment.
17 is a cross-sectional view illustrating a cross section of a light emitting device package including a light emitting device according to the embodiment.
18 is a perspective view showing a lighting apparatus including a light emitting device according to the embodiment.
19 is a cross-sectional view showing a section CC ′ of the lighting apparatus of FIG. 20.
20 is an exploded perspective view of a liquid crystal display including the light emitting device according to the embodiment.
21 is an exploded perspective view of a liquid crystal display including the light emitting device according to the embodiment.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when flipping a device shown in the figure, a device described as "below" or "beneath" of another device may be placed "above" of another device. Thus, the exemplary term "below" can include both downward and upward directions. The device can also be oriented in other directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

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 and area of each component do not entirely reflect actual size or area.

Further, the angle and direction mentioned in the description of the structure of the light emitting device in the embodiment are based on those shown in the drawings. In the description of the structure of the light emitting device in the specification, reference points and positional relationship with respect to angles are not explicitly referred to, refer to the related drawings.

1 is a perspective view showing a light emitting device according to an embodiment, FIG. 2 is a plan view showing the light emitting device of FIG. 1, FIG. 3 is a cross-sectional view showing a cross section of the light emitting device of FIG. 5 is a cross-sectional view illustrating an electrode according to another embodiment, and FIG. 6 is an explanatory diagram illustrating a light traveling path of a light emitting device according to an embodiment.

1 to 4, the light emitting device 100 according to the embodiment may be largely formed by including a supporting member 110, a light emitting structure, and an electrode. The light emitting structure may include a first semiconductor layer 120, a second semiconductor layer 140, and an active layer 130 between the first semiconductor layer 120 and the second semiconductor layer 140.

The support member 110 may be formed of any material having optical transparency, for example, sapphire (Al ₂ O ₃ ), GaN, ZnO, or AlO. However, the support member 110 is not limited thereto. Further, it can be a SiC supporting member having a higher thermal conductivity than a sapphire (Al ₂ O ₃ ) supporting member. However, it is preferable that the refractive index of the support member 110 is smaller than the refractive index of the first semiconductor layer 120 for the light extraction efficiency.

On the other hand, the support member 110 may be formed with a surface concave-convex pattern for improving the light extraction efficiency.

The surface irregularities pattern is formed on the surface opposite to the surface on which the light emitting structure is to be formed, and the forming method may be formed by an etching method, and preferably, dry etching, wet etching, or the like may be used, but is not limited thereto. . That is, the light extraction efficiency is increased by preventing total reflection of the light emitted by the surface irregularities.

A buffer layer (not shown) may be disposed on the support member 110 to mitigate lattice mismatch between the support member 110 and the first semiconductor layer 120 and allow the semiconductor layer to grow easily. The buffer layer (not shown) may be formed in a low temperature atmosphere, and may be formed of a material capable of alleviating the difference in lattice constant between the semiconductor layer and the support member. For example, materials such as GaN, InN, AlN, AlInN, InGaN, AlGaN, and InAlGaN can be selected and not limited thereto.

A light emitting structure including the first semiconductor layer 120, the active layer 130, and the second semiconductor layer 140 may be formed on the buffer layer (not shown).

The first semiconductor layer 120 may be located on a buffer layer (not shown). The first semiconductor layer 120 may be formed of an n-type semiconductor layer and may provide electrons to the active layer 130. The first semiconductor layer 120 is, for example, semiconductor material having a compositional formula of _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, etc. may be selected, and n-type dopants such as Si, Ge, Sn, and the like may be doped.

Further, the semiconductor layer 120 may further include an undoped semiconductor layer (not shown), but the present invention is not limited thereto. The un-doped semiconductor layer is a layer formed for improving the crystallinity of the first semiconductor layer 120 and has a lower electrical conductivity than the first semiconductor layer 120 without doping the n-type dopant. May be the same as the semiconductor layer 120.

The active layer 130 may be formed on the first semiconductor layer 120. The active layer 130 may be formed of a single or multiple quantum well structure, a quantum-wire structure, a quantum dot structure, or the like using a compound semiconductor material of Group 3-V group elements.

An active layer 130, the well having a composition formula of, for _{example, In x Al y Ga 1 -x-} y N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1) if formed of a quantum well structure, _Have a single or multiple 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) Can be. The well layer may be formed of a material having a band gap smaller than the band gap of the barrier layer.

A conductive clad layer (not shown) may be formed on and / or below the active layer 130. The conductive clad layer (not shown) may be formed of an AlGaN-based semiconductor and may have a band gap larger than that of the active layer 130.

The second semiconductor layer 140 may be implemented as a p-type semiconductor layer to inject holes into the active layer 130. A second semiconductor layer 140 is, for example, semiconductor material having a compositional formula of _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, etc. may be selected, and p-type dopants such as Mg, Zn, Ca, Sr, and Ba may be doped.

Meanwhile, an intermediate layer (not shown) may be formed between the active layer 130 and the second semiconductor layer 140, and the electrons injected into the active layer 130 from the first semiconductor layer 120 may be formed when a high current is applied. It may be an electron blocking layer that does not recombine in the active layer 130 and prevents a phenomenon flowing to the second semiconductor layer 140. The intermediate layer has a band gap relatively larger than that of the active layer 130, thereby preventing electrons injected from the first semiconductor layer 120 from being injected into the second semiconductor layer 140 without being recombined in the active layer 130. Can be. Accordingly, the probability of recombination of electrons and holes in the active layer 130 may be increased and leakage current may be prevented.

Meanwhile, the above-described intermediate layer may have a band gap larger than that of the barrier layer included in the active layer 130, and may be formed of a semiconductor layer including Al, such as p-type AlGaN, but is not limited thereto.

The first semiconductor layer 120, the active layer 130, and the second semiconductor layer 140 may be, for example, metal organic chemical vapor deposition (MOCVD) or chemical vapor deposition (CVD). Plasma-Enhanced Chemical Vapor Deposition (PECVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), and Sputtering It may be formed, but not limited thereto.

In addition, the doping concentrations of the conductive dopants in the first semiconductor layer 120 and the second semiconductor layer 140 may be uniformly or non-uniformly formed. That is, the plurality of semiconductor layers may be formed to have various doping concentration distributions, but the invention is not limited thereto.

In addition, the first semiconductor layer 120 may be implemented as a p-type semiconductor layer, the second semiconductor layer 140 may be implemented as an n-type semiconductor layer, and the n-type or p-type semiconductor on the second semiconductor layer 140. A third semiconductor layer (not shown) including a layer may be formed. Accordingly, the light emitting device 100 may have at least one of np, pn, npn, and pnp junction structures.

On the other hand, a plurality of protrusions 112 are disposed on the support member 110, and the outer surface of the protrusions 112 may include a reflective layer 112 for coating the protrusions 112. In addition, the protrusions 112 may be spaced apart from each other. However, the present invention is not limited thereto.

The material of the protrusion 112 is not limited, but may have the same material as the material of the support member 110.

The protrusion 112 may include any one of a conical column, a cylinder, a hemisphere, and a cube. However, the present invention is not limited thereto, and the protrusion 112 may have various shapes.

Since the protrusion 112 propagates the light generated in the active layer 130 to the side surface of the light emitting device 100, the light generated by the active layer 130 is prevented from being lost in the light emitting device 100. Can improve the light extraction efficiency.

The protrusion 112 may be formed by, for example, depositing using an E-beam or partially depositing in a PR (Photo Resist) method. However, the present invention is not limited thereto, and a dry etching method or a wet etching method may also be used.

Meanwhile, referring to FIG. 1B, a reflective layer 113 may be formed on the outer surface of the protrusion 112. That is, the protrusion 112 may be coated by the reflective layer 113. The reflective layer 113 coating the protrusion 112 may include a first layer (not shown) having at least a first refractive index and a second layer (not shown) having a second refractive index different from the first refractive index.

That is, the reflective layer 113 may have a structure in which layers having different refractive indices are alternately stacked repeatedly. For example, the first layer may be a high refractive index layer, and the second layer may be a low refractive index layer, but is not limited thereto. In addition, the reflective layer 113 may be stacked in two to thirty layers. However, the present invention is not limited thereto.

On the other hand, when λ is the wavelength of light generated in the active layer 130, n is the refractive index of the medium, and m is odd, the reflective layer 113 has a first refractive index and a high refractive index having a low refractive index with a thickness of mλ / 4n. The branch has a semiconductor laminate structure in which a second layer is alternately repeatedly stacked to obtain a reflectance of 95% or more in light of a specific wavelength band λ.

Accordingly, the first layer having the low refractive index and the second layer having the high refractive index may have a thickness of λ / 4 times the reference wavelength, and the thickness of each layer may be formed from 2 μm to 10 μm, and from 1 nm to It is common to be 10 nm.

The thickness of the reflective layer 113 is not limited, but may be 100 kPa to 10000 kPa.

In addition, each layer forming the reflective layer 113 may be formed of MxOy (M: Metal, O: Oxide, X, Y: constant). For example, the reflective layer 113 may include any one of SiO _{2 ,} Al ₂ O _{3 ,} SiC, AlB, BN, and TiO ₂ . However, the present invention is not limited thereto.

For example, SiO ₂ having a refractive index of 1.4 or Al ₂ O ₃ having a refractive index of 1.6 may be used for the first layer having a low refractive index, and TiO ₂ having a refractive index of 2 or more may be used for the second layer having a high refractive index, or TiO ₂ may be used for the first layer, and SiO ₂ may be used for the second layer. However, the present invention is not limited thereto.

On the other hand, the reflectance can be made larger by increasing the refractive index of the medium between the first layer having the low refractive index and the second layer having the high refractive index.

Since the reflective layer 113 has a bandgap energy greater than the oscillation wavelength, absorption of light does not occur well, and since most of the light is totally reflected, the reflectance of the light is large.

When the protrusions 112 are coated by the reflective layer 112, some of the light generated by the active layer 130 may be refracted without being reflected by the protrusions 112, and the light generated by the active layer 130 may be prevented from proceeding. It is possible to improve the luminous efficiency of the light emitting device 100 by reflecting to the outside such as the side of the (100).

The electrode connects the light emitting device 100 to a power source. The electrode may include a first electrode 170 electrically connected to the first semiconductor layer 120 and a second electrode 180 disposed on the second semiconductor layer 140.

The first electrode 170 may be formed on the first semiconductor layer 120. The position at which the first electrode 170 is formed is not limited, and a plurality of first electrodes 170 may be formed in consideration of the size of the light emitting device 100. In addition, as shown in FIG. 2, some regions of the second semiconductor layer 140 and the active layer 130 are removed, a portion of the first semiconductor layer 120 is exposed, and the exposed first semiconductor layer 120 is exposed. The first electrode 170 may be formed on the upper surface. However, the present invention is not limited thereto, and the support member 110 may be removed and the first electrode 170 may be formed on the exposed surface of the first semiconductor layer 120.

The method of removing the top surface of the first semiconductor layer 120 is not limited, but a wet etching method or a dry etching method may be used.

The second electrode 180 may be disposed on the second semiconductor layer 140. The lower surface of the second electrode 180 may include a protrusion 10 protruding in the thickness direction of the light emitting structure, and an angle formed by the inclined surfaces of the protrusion 10 may be 120 degrees to 170 degrees.

Referring to FIG. 6, when the angles formed by the inclined surfaces of the protrusions 10 are greater than 170 degrees, the light directed to the second electrode 180 of the light emitted from the active layer 130 may not be effectively emitted to the outside of the light emitting device. When the contact area between the second electrode 180 and the second semiconductor layer 140 is reduced, and the angle between the inclined surfaces of the protrusions 10 is smaller than 120 degrees, the thickness of the second semiconductor layer 140 is increased. Excessive second electrode 180 may be formed. Therefore, an angle formed by the inclined surfaces of the protrusion 10 may be 120 degrees to 170 degrees.

In addition, the shape of the protrusion 10 may include any one of a cone, a square pyramid, and a triangular pyramid, or two or more shapes to effectively emit light to the outside of the light emitting device 100. However, the present invention is not limited thereto. In addition, the cross-sectional shape of the protrusion 10 may include a triangle.

4 and 5, the second electrode 180 is a reflective electrode layer 180b disposed on the second semiconductor layer 140 and an anti-oxidation electrode layer 180c disposed on the reflective electrode layer 180b. It may include. In addition, a bonding electrode layer 180a may be disposed under the reflective electrode layer 180b.

The inclined surface of the protrusion 10 may be rounded or have a curvature as shown in FIGS. 5B and 5C.

The depth d1 into which the second electrode 180 is inserted into the second semiconductor layer 140 may be 0.1 to 0.5 times the thickness of the second semiconductor layer 140.

The reflective electrode layer 180b may be connected to the second semiconductor layer 140, and the shape of the reflective electrode layer 180b viewed from above may have various shapes such as a circle, a triangle, and a rectangle. In FIG. 1, it is illustrated as a circle, but is not limited thereto.

The reflective electrode layer 180b may include a metal of a reflective material, for example, aluminum (Al), rhodium (Rh), tin (Sn), silver (Ag), silver (Ag) -based alloy, and silver (Ag). It may include any one selected from the group consisting of) oxide. In addition, the reflective electrode layer 180b may have a single layer or a multilayer structure. However, the present invention is not limited thereto. However, the position at which the protrusion 10 is formed is not limited, but may be preferably formed in the reflective electrode layer 180b.

Although the thickness of the reflecting electrode layer 180b is not limited, it is usually 2800 mW to 3200 mW.

The bonding electrode layer 180a may be disposed under the reflective electrode layer 180b. The shape of the bonding electrode layer 180a is not limited and may have various shapes. In this case, the protrusion 10 may be formed on the bonding electrode layer 180a.

The bonding electrode layer 180a may have a single layer or a multilayer structure, and may be formed of, for example, chromium (Cr) or titanium (Ti) as a material having excellent adhesion with the second semiconductor layer 140. . However, the present invention is not limited thereto.

Although the thickness of the bonding electrode layer 180a is not limited, it is common that the bonding electrode layer 180a is 15 kPa to 25 kPa.

The shape of the anti-oxidation electrode layer 180c is not limited and may be disposed on the reflective electrode layer 180b. The anti-oxidation electrode layer 180c serves to prevent oxidation of the reflective electrode layer 180b.

The anti-oxidation electrode layer 180c is a conductive material resistant to oxidation, for example, gold (Au), rhodium (Rh), palladium (Pd), copper (Cu), nickel (Ni), ruthenium (Ru), and iridium ( Ir) and platinum (Pt). However, the present invention is not limited thereto.

The thickness of the anti-oxidation electrode layer 180c is not limited, but is usually 2800 kPa to 3200 kPa.

The upper surface of the second electrode 180 may be flat as shown in FIG. 4, or may be formed to correspond to the protrusion 10 as shown in FIG. 5. However, the present invention is not limited thereto.

Referring to FIG. 6, when the second electrode 180 has the protrusion 10, light generated from the active layer 130 may be secured while securing a contact area between the second semiconductor layer 140 and the second electrode 180. Since the area to be absorbed is reduced, the luminous efficiency of the light emitting device 100 can be improved. In addition, the light emitted from the active layer 130 toward the second electrode 180 is reflected on the inclined surface of the protrusion 10 is discharged to the outside of the light emitting device 100 can be improved luminous efficiency.

In addition, since light emitted from the active layer 130 toward the lower portion of the light emitting device 100 is reflected by the protrusion 112 and is emitted to the outside, the luminous efficiency may be improved.

7 is a cross-sectional view showing a light emitting device according to another embodiment.

Referring to FIG. 7, there is a difference between the light emitting device 100A according to the embodiment including the transmissive electrode layer 150A and the current limiting layer 160A, compared to the embodiment of FIG. 3.

The transmissive electrode layer 150A may be included between the second electrode 180 and the second semiconductor layer 140.

The transparent electrode layer 150A includes ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrO _x , RuO _x , RuO _x / ITO, Ni / IrO _x / Au, and Ni / IrO _x / Au / ITO, and may be formed, and formed on the entire outer surface of the second semiconductor layer 140, thereby forming a current grouping phenomenon. Can be prevented.

The second electrode 180 may pass through the transparent electrode layer 150A and be connected to the second semiconductor layer 140. However, the present invention is not limited thereto.

The semiconductor device may further include a current limiting layer 160A formed in the second semiconductor layer 140 so that at least a portion of the second electrode 180 is vertically overlapped with the position where the second electrode 180 is formed.

The current limiting layer 160A includes a non-conductive or weakly conductive material. Preferably, the current limiting layer 160A may be made of aluminum nitride (Al ₂ O ₃ ) including silicon dioxide (SiO ₂ ).

The current limiting layer 160A is provided to prevent a current grouping phenomenon in which electrons are concentrated under the electrode.

In addition, the area of the current limiting layer 160A is not limited, but may be wider than that of the second electrode 180. Therefore, the current grouping phenomenon can be prevented.

8 is a plan view illustrating a light emitting device according to still another embodiment, and FIG. 9 is a view illustrating a B-B cross section of the light emitting device of FIG. 8.

8 and 9, the light emitting device 200 according to the embodiment has a difference in the structure of the first electrode 270 and the second electrode 280 compared to the embodiment of FIG. 2.

The first electrode 270 is connected to the first electrode pad 272 and the first electrode pad 272 disposed on one side of the first semiconductor layer 120 and at least one first electrode wing 374 disposed to the other side. ) May be included. However, the present invention is not limited thereto.

The second electrode 280 is connected to the second electrode pad 282 and the second electrode pad 282 disposed on one side of the second semiconductor layer 240, and at least one second electrode wing 284 disposed to the other side. , 286). However, the present invention is not limited thereto.

Here, the bottom surface of the second electrode pad 282 and the second electrode wings 284 and 286 may include a protrusion 10 protruding downward as shown in FIG. 9.

As such, when the first electrode 270 and the second electrode 280 are disposed, the light emitting efficiency of the light emitting device 200 may be improved while supplying a current to the light emitting device 200 effectively.

10 is a cross-sectional view illustrating a light emitting device according to yet another embodiment.

Referring to FIG. 10, the light emitting device 300 according to the embodiment may include a support member 310, a first electrode layer 370 disposed on the support member 310, and a first electrode disposed on the first electrode layer 370. The light emitting structure including the semiconductor layer 320, the active layer 330, and the second semiconductor layer 340, and the second electrode 380 disposed on the second semiconductor layer 340 may be included.

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

That is, the support member 310 may be formed of any one selected from a metal, for example, Au, Ni, W, Mo, Cu, Al, Ta, Ag, Pt, Cr, or may be formed of two or more alloys. The above materials can be laminated and formed. In addition, the support member 310 is Si, Ge, GaAs, ZnO, SiC, SiGe, GaN, Ga ₂ O ₃ It may be implemented as a carrier wafer such as.

The support member 310 may improve the thermal stability of the light emitting device 300 by facilitating the emission of heat generated from the light emitting device 300.

Meanwhile, a first electrode layer 370 may be formed on the support member 310, and the first electrode layer 370 may be an ohmic layer (not shown), a reflective layer (not shown), or a bonding layer. It may include at least one layer (bonding layer) (not shown). For example, the first electrode layer 370 may be a structure of an ohmic layer / reflective layer / bonding layer, a stacked structure of an ohmic layer / reflective layer, or a structure of a reflective layer (including ohmic) / bonding layer, but is not limited thereto. For example, the first electrode layer 370 may have a form in which a reflective layer and an ohmic layer are sequentially stacked on the bonding layer.

The reflective layer (not shown) may be disposed between the ohmic layer (not shown) and the bonding layer (not shown), and have excellent reflective properties, for example, Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg , Zn, Pt, Au, Hf, or a combination of these materials, or a combination of these materials or IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, to form a multi-layer using a transparent conductive material such as Can be. Further, the reflective layer (not shown) can be laminated with IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni and the like. In addition, when the reflective layer (not shown) is formed of a material in ohmic contact with the light emitting structure (eg, the first semiconductor layer 320), the ohmic layer (not shown) may not be separately formed, but is not limited thereto.

The ohmic layer (not shown) is in ohmic contact with the lower surface of the light emitting structure, and may be formed in a layer or a plurality of patterns. The ohmic layer (not shown) may be formed of a transparent electrode layer and a metal. For example, ITO (indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tin oxide) ), IGZO (indium gallium zinc oxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IrO _x , RuO _x , RuO _x / Ni, Ag, Ni / IrO _x / Au, and Ni / IrO _x / Au / ITO. The ohmic layer (not shown) is for smoothly injecting the carrier into the first semiconductor layer 320 and is not necessarily formed.

In addition, the first electrode layer 370 may include a bonding layer (not shown), wherein the bonding layer (not shown) may be a barrier metal or a bonding metal, for example, Ti, Au, Sn, or Ni. It may include, but is not limited to, at least one of Cr, Ga, In, Bi, Cu, Ag, or Ta.

The light emitting structure may include at least a first semiconductor layer 320, an active layer 330, and a second semiconductor layer 340, and an active layer 330 between the first semiconductor layer 320 and the second semiconductor layer 340. ) May be made to the published configuration.

The first semiconductor layer 320 may be formed on the first electrode layer 370. The first semiconductor layer 320 may be implemented as a p-type semiconductor layer doped with a p-type dopant. The p-type semiconductor layer contains a semiconductor material, for example, having a compositional formula of _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1) GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN and the like may be selected, and p-type dopants such as Mg, Zn, Ca, Sr, and Ba may be doped.

An active layer 330 may be formed on the first semiconductor layer 320. The active layer 330 may be formed of a single or multiple quantum well structure, a quantum-wire structure, a quantum dot structure, or the like using a compound semiconductor material of a group III-V group element.

Well active layer 330 has a composition formula 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 band gap smaller than the band gap of the barrier layer.

In addition, when the active layer 330 has a multi-quantum well structure, each well layer (not shown) may have different In contents and different band gaps.

A conductive cladding layer (not shown) may be formed on or under the active layer 330. The conductive clad layer (not shown) may be formed of an AlGaN-based semiconductor and may have a band gap larger than that of the active layer 330.

Meanwhile, an intermediate layer (not shown) may be formed between the active layer 330 and the first semiconductor layer 320, and electrons injected into the active layer 330 from the second semiconductor layer 340 may be formed when a high current is applied. It may be an electron blocking layer that prevents the phenomenon of flowing to the first semiconductor layer 320 without recombination from the active layer 330. The intermediate layer (not shown) has a band gap relatively larger than that of the active layer 330, whereby electrons injected from the second semiconductor layer 340 are injected into the first semiconductor layer 320 without being recombined in the active layer 330. The phenomenon can be prevented. Accordingly, the probability of recombination of electrons and holes in the active layer 330 may be increased and leakage current may be prevented.

On the other hand, the above-described intermediate layer may have a bandgap larger than the bandgap of the barrier layer included in the active layer 330, for example, may be formed of a semiconductor layer including Al, such as AlGaN, but is not limited thereto.

The second semiconductor layer 340 may be formed on the active layer 330. The second semiconductor layer 340 may be implemented as an n-type semiconductor layer, and the n-type semiconductor layer may be, for example, In _x Al _y Ga _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0). ≦ x + y ≦ 1), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, and the like, and for example, Si, Ge, Sn, Se, Te and The same n-type dopant may be doped.

The light emitting structure may include a third semiconductor layer (not shown) having a polarity opposite to that of the second semiconductor layer 340 on the second semiconductor layer 340. In addition, the first semiconductor layer 320 may be an n-type semiconductor layer, and the second semiconductor layer 340 may be implemented as a p-type semiconductor layer. Accordingly, the light emitting structure layer may include at least one of an N-P junction, a P-N junction, an N-P-N junction, and a P-N-P junction structure.

A light extraction structure (not shown) may be formed on the light emitting structure.

The light extracting structure may be formed in a part or the entire area of the upper surface of the second semiconductor layer 340. The light extracting structure may be formed by performing etching on at least one region of the transparent electrode layer (not shown) or the upper surface of the second semiconductor layer 340, but is not limited thereto. The etching process may include a wet or / and dry etching process, and as the etching process is performed, the top surface of the translucent electrode layer (not shown) or the top surface of the second semiconductor layer 340 may have roughness to form a light extraction structure. It may include. The roughness may be irregularly formed in a random size, but is not limited thereto. The roughness may be at least one of a texture pattern, a concave-convex pattern, and an uneven pattern, which is an uneven surface.

The roughness may be formed to have various shapes such as a cylinder, a polygonal column, a cone, a polygonal pyramid, a truncated cone, a polygonal pyramid, and the like, preferably including a horn shape.

The light extraction structure may be formed by a method such as photo electrochemical (PEC), but is not limited thereto. As the light extracting structure 284 is formed on the transparent electrode layer (not shown) or on the upper surface of the second semiconductor layer 340, the light generated from the active layer 330 is transmitted to the transparent electrode layer (not shown), or the second semiconductor layer. Since total reflection from the upper surface of the 340 may be prevented from being reabsorbed or scattered, it may contribute to the improvement of light extraction efficiency of the light emitting device 300.

The passivation 390 may be formed on the side and upper regions of the light emitting structure, and the passivation 390 may be formed of an insulating material.

A second electrode 380 electrically connected to the second semiconductor layer 340 may be formed on the second semiconductor layer 340, and the second electrode 380 may include at least one pad or an electrode having a predetermined pattern. It may include. The second electrode 380 may be disposed in the center region, the outer region, or the corner region of the upper surface of the second semiconductor layer 340, but is not limited thereto. The second electrode 380 may be disposed in a region other than the second semiconductor layer 340, but is not limited thereto.

The lower surface of the second electrode 380 may include a protrusion 10 protruding in the thickness direction of the light emitting structure, and an angle formed by the inclined surfaces of the protrusion 10 may be 120 degrees to 170 degrees.

The configuration of the second electrode 380 and the protrusion 10 is as described above.

11 to 15 are flowcharts illustrating a method of manufacturing a light emitting device according to the embodiment.

Referring to FIG. 11, first, the support member 110 is prepared.

Thereafter, the protrusion 112 is formed on the support member 110. The formation method of the protrusion 112 is not limited, but for example, the protrusion 112 may be formed by depositing using an E-beam or partially depositing in a PR (Photo Resist) method. However, the present invention is not limited thereto, and a dry etching method or a wet etching method may also be used.

Referring to FIG. 12, a reflective layer 113 is formed on the surface of the protrusion 112. The method of forming the reflective layer 113 is not limited, but may be formed by a deposition method.

Referring to FIG. 13, the light emitting structure is formed by sequentially forming the first semiconductor layer 120, the active layer 130, and the second semiconductor layer 140 on the support member 110.

The light emitting structure may be, for example, Metal Organic Chemical Vapor Deposition (MOCVD), Chemical Vapor Deposition (CVD), Plasma-Enhanced Chemical Vapor Deposition (PECVD), or Molecular Beam Growth (MBE). Molecular Beam Epitaxy), Hydride Vapor Phase Epitaxy (HVPE), and the like, but are not limited thereto.

Referring to FIG. 14, at least a top surface of the first semiconductor layer 120 may be mesa-etched on the second region S2 of the upper surface of the first region S1 and the second semiconductor layer 140. Some can be exposed.

Mesa etching may be performed by dry etching or wet etching after forming the mask.

In this case, a transparent electrode layer (not shown) may be formed on the second semiconductor layer 140.

The transparent electrode layer 150 may be formed in an entire region of the upper surface of the second semiconductor layer 140 or in a partial region.

The translucent electrode layer may be formed by any one of e-beam deposition, sputtering, and plasma enhanced chemical vapor deposition (PECVD), but is not limited thereto.

Referring to FIG. 15, the first electrode 170 is formed on the first semiconductor layer 120, and the second electrode 180 is formed on the second region S2 of the second semiconductor layer 140. The light emitting device 100 according to the embodiment may be provided.

 The first and second electrodes 170 and 180 may be formed by, for example, a deposition method or a plating method, but are not limited thereto.

16 is a perspective view illustrating a light emitting device package including a light emitting device according to an embodiment, and FIG. 17 is a cross-sectional view illustrating a light emitting device package including a light emitting device according to an embodiment.

16 and 17, the light emitting device package 500 may include a body 510 having a cavity 520, first and second lead frames 540 and 550 mounted on the body 510, and a first one. And a light emitting device 530 electrically connected to the second lead frames 540 and 550, and an encapsulant (not shown) filled in the cavity 520 to cover the light emitting device 530.

The body 510 may be made of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), liquid crystal polymer (PSG), polyamide 9T (SPS), a metal material, sapphire (Al ₂ O ₃ ), beryllium oxide (BeO), and a printed circuit board (PCB). The body 510 may be formed by injection molding, etching, or the like, but is not limited thereto.

The inner surface of the body 510 may be formed with an inclined surface. The reflection angle of the light emitted from the light emitting device 530 can be changed according to the angle of the inclined surface, and thus the directivity angle of the light emitted to the outside can be controlled.

Concentration of light emitted to the outside from the light emitting device 530 increases as the directivity angle of light decreases. Conversely, as the directivity angle of light increases, the concentration of light emitted from the light emitting device 530 decreases.

The shape of the cavity 520 formed in the body 510 may be circular, rectangular, polygonal, elliptical, or the like, and may have a curved shape, but the present invention is not limited thereto.

The light emitting device 530 is mounted on the first lead frame 540 and may be, for example, a light emitting device emitting light of red, green, blue, white, or UV (ultraviolet) light emitting device emitting ultraviolet light. But it is not limited thereto. In addition, one or more light emitting elements 530 may be mounted.

The light emitting device 530 may be a horizontal type or a vertical type formed on the upper or lower surface of the light emitting device 530 or a flip chip Applicable.

The encapsulant (not shown) may be filled in the cavity 520 to cover the light emitting device 530.

The encapsulant (not shown) may be formed of silicon, epoxy, or other resin material. The encapsulant may be filled in the cavity 520 and ultraviolet or thermally cured.

In addition, the encapsulant (not shown) may include a phosphor, and the phosphor may be selected to be a wavelength of light emitted from the light emitting device 530 so that the light emitting device package 500 may emit white light.

The phosphor may be one of a blue light emitting phosphor, a blue light emitting phosphor, a green light emitting phosphor, a sulfur green light emitting phosphor, a yellow light emitting phosphor, a yellow red light emitting phosphor, an orange light emitting phosphor, and a red light emitting phosphor depending on the wavelength of light emitted from the light emitting device 530 Can be applied.

That is, the phosphor may be excited by the light having the first light emitted from the light emitting device 530 to generate the second light. For example, when the light emitting element 530 is a blue light emitting diode and the phosphor is a yellow phosphor, the yellow phosphor may be excited by blue light to emit yellow light, and blue light and blue light emitted from the blue light emitting diode As the excited yellow light is mixed, the light emitting device package 500 can provide white light.

Similarly, when the light emitting element 530 is a green light emitting diode, the magenta phosphor or the blue and red phosphors are mixed, and when the light emitting element 530 is a red light emitting diode, the cyan phosphors or the blue and green phosphors are mixed For example.

Such a fluorescent material may be a known fluorescent material such as a YAG, TAG, sulfide, silicate, aluminate, nitride, carbide, nitridosilicate, borate, fluoride or phosphate.

The first and second lead frames 540 and 550 may be formed of a metal material such as titanium, copper, nickel, gold, chromium, tantalum, (Pt), tin (Sn), silver (Ag), phosphorus (P), aluminum (Al), indium (In), palladium (Pd), cobalt (Co), silicon (Si), germanium , Hafnium (Hf), ruthenium (Ru), and iron (Fe). Also, the first and second lead frames 540 and 550 may be formed to have a single layer or a multilayer structure, but the present invention is not limited thereto.

The first and second lead frames 540 and 550 are separated from each other and electrically separated from each other. The light emitting element 530 is mounted on the first and second lead frames 540 and 550 and the first and second lead frames 540 and 550 are in direct contact with the light emitting element 530, And may be electrically connected through a conductive material such as a conductive material. In addition, the light emitting device 530 may be electrically connected to the first and second lead frames 540 and 550 through wire bonding, but is not limited thereto. Accordingly, when power is supplied to the first and second lead frames 540 and 550, power may be applied to the light emitting device 530. Meanwhile, a plurality of lead frames (not shown) may be mounted in the body 510 and each lead frame (not shown) may be electrically connected to the light emitting device 530, but is not limited thereto.

FIG. 18 is a perspective view illustrating a lighting apparatus including a light emitting device according to an embodiment, and FIG. 19 is a cross-sectional view illustrating a C-C 'cross section of the lighting apparatus of FIG.

18 and 19, the lighting device 600 may include a body 610, a cover 630 fastened to the body 610, and a closing cap 650 positioned at both ends of the body 610. have.

A light emitting device module 640 is coupled to a lower surface of the body 610. The body 610 is electrically conductive so that heat generated from the light emitting device package 644 can be emitted to the outside through the upper surface of the body 610. [ And a metal material having an excellent heat dissipation effect.

The light emitting device package 644 may be mounted on the PCB 642 in a multi-color, multi-row manner to form an array. The light emitting device package 644 may be mounted at equal intervals or may be mounted with various spacings as required. As the PCB 642, MPPCB (Metal Core PCB) or FR4 material PCB can be used.

Since the light emitting device package 644 may have an improved heat dissipation function including an extended lead frame (not shown), reliability and efficiency of the light emitting device package 644 may be improved, and the light emitting device package 622 and the light emitting device may be improved. The service life of the lighting device 600 including the device package 644 may be extended.

The cover 630 may be formed in a circular shape so as to surround the lower surface of the body 610, but is not limited thereto.

The cover 630 protects the internal light emitting element module 640 from foreign substances or the like. The cover 630 may include diffusion particles so as to prevent glare of light generated in the light emitting device package 644 and uniformly emit light to the outside, and may include at least one of an inner surface and an outer surface of the cover 630 A prism pattern or the like may be formed on one side. Further, the phosphor may be applied to at least one of the inner surface and the outer surface of the cover 630.

Since the light generated in the light emitting device package 644 is emitted to the outside through the cover 630, the cover 630 must have a high light transmittance and sufficient heat resistance to withstand the heat generated in the light emitting device package 644 The cover 630 is preferably formed of a material including polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), or the like .

The finishing cap 650 is located at both ends of the body 610 and can be used to seal the power supply unit (not shown). In addition, the finishing cap 650 is provided with the power supply pin 652, so that the lighting apparatus 600 according to the embodiment can be used immediately without a separate device on the terminal from which the conventional fluorescent lamp is removed.

20 is an exploded perspective view of a liquid crystal display including the light emitting device according to the embodiment.

20 is an edge-light method, and the liquid crystal display device 700 may include a liquid crystal display panel 710 and a backlight unit 770 for providing light to the liquid crystal display panel 710.

The liquid crystal display panel 710 can display an image using light provided from the backlight unit 770. The liquid crystal display panel 710 may include a color filter substrate 712 and a thin film transistor substrate 714 facing each other with a liquid crystal therebetween.

The color filter substrate 712 can realize the color of an image to be displayed through the liquid crystal display panel 710.

The thin film transistor substrate 714 is electrically connected to a printed circuit board 718 on which a plurality of circuit components are mounted via a driving film 717. The thin film transistor substrate 714 may apply a driving voltage provided from the printed circuit board 718 to the liquid crystal in response to a driving signal provided from the printed circuit board 718. [

The thin film transistor substrate 714 may include a thin film transistor and a pixel electrode formed as a thin film on another substrate of a transparent material such as glass or plastic.

The backlight unit 770 includes a light emitting element module 720 that outputs light, a light guide plate 730 that changes the light provided from the light emitting element module 720 into a surface light source and provides the light to the liquid crystal display panel 710, A plurality of films 752, 766, and 764 for uniformly distributing the luminance of light provided from the light guide plate 730 and improving vertical incidence and a reflective sheet (reflective plate) for reflecting light emitted to the rear of the light guide plate 730 to the light guide plate 730 747).

The light emitting device module 720 may include a PCB substrate 722 for mounting a plurality of light emitting device packages 724 and a plurality of light emitting device packages 724 to form an array. In this case, the reliability of the mounting of the bent light emitting device package 724 can be improved.

Meanwhile, the backlight unit 770 includes a diffusion film 766 that diffuses light incident from the light guide plate 730 toward the liquid crystal display panel 710, and a prism film 752 that concentrates the diffused light to improve vertical incidence. It may be configured as), and may include a protective film 764 for protecting the prism film 750.

21 is an exploded perspective view of a liquid crystal display including the light emitting device according to the embodiment. However, the parts shown and described in FIG. 20 will not be repeatedly described in detail.

21 is a direct view, the liquid crystal display device 800 may include a liquid crystal display panel 810 and a backlight unit 870 for providing light to the liquid crystal display panel 810.

Since the liquid crystal display panel 810 is the same as that described with reference to FIG. 20, a detailed description thereof will be omitted.

The backlight unit 870 includes a plurality of light emitting element modules 823, a reflective sheet 824, a lower chassis 830 in which the light emitting element module 823 and the reflective sheet 824 are accommodated, And a plurality of optical films 860. The diffuser plate 840 and the plurality of optical films 860 are disposed on the light guide plate 840. [

LED Module 823 A plurality of light emitting device packages 822 and a plurality of light emitting device packages 822 may be mounted to include a PCB substrate 821 to form an array.

The reflective sheet 824 reflects light generated from the light emitting device package 822 in a direction in which the liquid crystal display panel 810 is positioned, thereby improving light utilization efficiency.

Light generated in the light emitting element module 823 is incident on the diffusion plate 840 and an optical film 860 is disposed on the diffusion plate 840. The optical film 860 may include a diffusion film 866, a prism film 850, and a protective film 864.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It can be seen 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 element 120 first semiconductor layer
130: active layer 140: second semiconductor layer

Claims (20)

A light emitting structure including a first semiconductor layer, a second semiconductor layer, and an active layer between the first semiconductor layer and the second semiconductor layer;
A first electrode electrically connected to the first semiconductor layer;
A second electrode disposed on the second semiconductor layer,
The lower surface of the second electrode includes a protrusion formed in the thickness direction of the light emitting structure,
An angle formed by the inclined surfaces of the protrusion is 120 to 170 degrees. The method of claim 1,
The protrusion has a shape of any one of a cone, a square pyramid and a triangular pyramid. The method of claim 1,
The cross-sectional shape of the protruding portion, the light emitting device comprising a triangle. The method of claim 1,
Wherein the second electrode comprises:
A reflective electrode layer disposed on the second semiconductor layer;
Light emitting device comprising an anti-oxidation electrode layer disposed on the reflective electrode layer. 5. The method of claim 4,
The protrusion is formed in the reflective electrode layer. 5. The method of claim 4,
The second electrode further comprises a bonding electrode layer disposed under the reflective electrode layer. The method according to claim 6,
The bonding electrode layer includes any one of chromium (Cr) and titanium (Ti). The method according to claim 6,
The bonding electrode layer has a thickness of 15 kW to 25 kW. 5. The method of claim 4,
The reflective electrode layer,
A light emitting device comprising any one selected from the group consisting of aluminum (Al), rhodium (Rh), tin (Sn), silver (Ag), silver (Ag) -based alloys and silver (Ag) -based oxides. 5. The method of claim 4,
The reflective electrode layer has a thickness of 2800 Å to 3200 발광. 5. The method of claim 4,
The anti-oxidation electrode layer includes at least one of gold (Au), rhodium (Rh), palladium (Pd), copper (Cu), nickel (Ni), ruthenium (Ru), iridium (Ir), and platinum (Pt). Light emitting element. 5. The method of claim 4,
The anti-oxidation electrode layer has a thickness of 7500 kV to 8500 kV. The method of claim 1,
The upper surface of the second electrode has a flat shape. The method of claim 1,
Wherein the second electrode comprises:
At least one second electrode pad disposed on one side of the second semiconductor layer; And
A light emitting device comprising at least one second electrode wing connected to the second electrode pad and disposed in the other direction. The method of claim 1,
A translucent electrode layer is further included between the second electrode and the second semiconductor layer.
The second electrode is connected to the second semiconductor layer through the light transmitting electrode layer. The method of claim 1,
And a current limiting layer disposed at a position vertically overlapping with the second electrode of the second semiconductor layer. The method of claim 1,
A light emitting device further comprising a support member under the first semiconductor layer. 18. The method of claim 17,
The light emitting device includes a plurality of protrusions on the support member to improve the light extraction efficiency. 19. The method of claim 18,
The outer surface of the plurality of protrusions further comprises a reflective layer for coating the plurality of protrusions. The method of claim 1,
The light emitting device further comprises a passivation formed to surround a portion of the side and the upper surface of the light emitting structure.

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