KR20130023939A - Light emitting device - Google Patents

Abstract

PURPOSE: A light emitting device is provided to increase optical extraction efficiency by using an optical extraction structure including nano holes. CONSTITUTION: A light emitting structure includes a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer. The active layer is arranged between the first conductive semiconductor layer and the second conductive semiconductor layer. The light emitting structure generates ultraviolet ray. An optical extraction structure(180) is arranged on the light emitting structure. The optical extraction structure includes a nano hole(184).

Description

[0001]

An embodiment relates to a light emitting element.

Light emitting devices such as light emitting diodes or laser diodes using semiconductors of Group 3-5 or 2-6 compound semiconductor materials of semiconductors have various colors such as red, green, blue, and ultraviolet rays due to the development of thin film growth technology and device materials. It is possible to realize efficient white light by using fluorescent materials or combining colors, and it has low power consumption, semi-permanent life, fast response speed, safety and environmental friendliness compared to conventional light sources such as fluorescent and incandescent lamps. Has an advantage.

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.

In order to obtain a high brightness light emitting diode, there are a method of improving the quality of the active layer to increase the internal quantum efficiency, and a method of increasing the light extraction efficiency by helping to emit the light generated from the active layer to the outside and collecting in the required direction.

Light extraction efficiency is determined by the ratio of electrons injected into the light emitting diode and photons emitted out of the light emitting diode, and the higher the light extraction efficiency, the brighter the light emitting diode.

In the nitride-based light emitting diode, when the light emitted from the active layer exits to the outside, total reflection condition occurs due to the difference in refractive index between the nitride-based semiconductor material and the outside, so that light incident at an angle greater than or equal to the critical angle of total reflection does not escape to the outside and is reflected And then back inside the device.

In order to solve such a problem, there is a method of forming a roughness on the surface by etching the surface of the light emitting diode, but by performing an additional etching process, the manufacturing process may be complicated and take a long time, and light emitted from the light emitting diode to the outside The total reflection at this interface and re-incident to the inside can reduce the light efficiency of the light emitting diode.

The embodiment aims to increase the light extraction efficiency of the light emitting device.

Embodiments include a light emitting structure including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer; And a light extraction structure disposed on the light emitting structure and including a nanocavity.

The light extraction structure may include a first layer in which nano irregularities are formed and a second layer disposed on the first layer with a nano cavity interposed therebetween.

In the light extracting structure, nano irregularities may be formed in the first conductive semiconductor layer or the second conductive semiconductor layer, and a second layer may be disposed with the nano irregularities and the nanocavity interposed therebetween.

At least a part of the second layer may be inserted into the nano irregularities.

The first layer may include an oxide and may include any one of ITO, SiO ₂ , Al ₂ O ₃ , ZnO, TiO ₂ , and a polymer.

Nano irregularities may be 400 nanometers to 1 micrometer in depth.

The cross section of the nano unevenness may be circular, and the diameter of the nano unevenness may be 0.1 micrometer to 0.5 micrometer.

Nano irregularities may be smaller in size than the wavelength of light emitted from the active layer.

Nano irregularities may be arranged regularly.

Nano irregularities may have a period of 0.5 to 0.7 micrometers.

The second layer can be any one of ITO, oxide, epoxy material.

The height of the nanocavity may be lower than the height of the nano irregularities.

The height of the nanocavity may be 80 to 100% of the height of the nano irregularities.

The cross section of the nanocavity is circular, and the diameter of the cross section of the nanocavity may be 0.1 micrometer to 0.5 micrometer.

The second layer may have a refractive index of 1.5 to 2.5.

The first layer may be made of the same material as the second layer.

The bottom surface of the second layer is not parallel to the bottom surface of the recessed portion of the first layer or is not parallel to the bottom surface of the recessed portion of the first conductive semiconductor layer or the second conductive semiconductor layer.

The first layer may be in contact with the second conductivity type semiconductor layer.

The light emitting structure may generate light having a wavelength in the ultraviolet region.

In the light emitting device according to the embodiment, a light extraction structure including nanocavities is formed on the surface of the light emitting structure, and the light emitted from the active layer passes through the nanocavities and is refracted at the boundary of each layer, thereby improving the light emission angle. .

1 is a cross-sectional view of a first embodiment of a light emitting element,
2 is a cross-sectional view of a second embodiment of a light emitting element,
FIG. 3A is a detailed view of region 'A' of FIG. 1,
3B is a plan view of region 'A' of FIG. 1,
FIG. 4A is a detailed view of region 'B' of FIG. 2;
4B is a plan view of region 'B' of FIG. 2,
5 and 6 are cross-sectional views of the third and fourth embodiments of the light emitting device,
7A to 7H are views showing a first embodiment of a method of manufacturing a light emitting device;
8A to 8D are views showing a second embodiment of the manufacturing method of the light emitting device,
9A to 9C are views showing a third embodiment of the method of manufacturing a light emitting device;
10A to 10F are views showing a fourth embodiment of the method of manufacturing a light emitting device,
11 is a view showing the operation of the light emitting device according to the embodiment,
12a and 12b show the light extraction structure of the light emitting device,
13 is a view showing an embodiment of a light emitting device package;
14 is a view showing an embodiment of a head lamp including a light emitting device package,
15 is a diagram illustrating an embodiment of a display device including a light emitting device package.

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, when described as being formed on the "on or under" of each element, the (up) or down (on) or under) includes both two elements being directly contacted with each other or one or more other elements are formed indirectly 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. In addition, the size of each component does not necessarily reflect the actual size.

1 is a sectional view of a first embodiment of a light emitting element.

The light emitting device 100 according to the embodiment includes a bonding layer 150, a reflective layer 140, an ohmic layer 130, a light emitting structure 120, and a light extracting structure 180 on a conductive support substrate (metal support) 160. It is made, including.

Since the conductive support substrate 160 may serve as a second electrode, a metal having excellent electrical conductivity may be used, and a metal having high thermal conductivity may be used because it must be able to sufficiently dissipate heat generated when the light emitting device is operated.

The conductive support substrate 160 may be made of, for example, a material selected from the group consisting of molybdenum (Mo), silicon (Si), tungsten (W), copper (Cu), and aluminum (Al) or an alloy thereof. Also, gold (Au), copper alloy (Cu Alloy), nickel (Ni), copper-tungsten (Cu-W), carrier wafers (e.g. GaN, Si, Ge, GaAs, ZnO, SiGe, SiC, SiGe) , Ga ₂ O _3, etc.) may be optionally included.

In addition, the conductive support substrate 160 may have a mechanical strength enough to be separated into a separate chip through a scribing process and a breaking process without bringing warpage to the entire nitride semiconductor. have.

The bonding layer 150 combines the reflective layer 140 and the conductive support substrate 160, and the reflective layer 140 may function as an adhesion layer. The bonding layer 150 is made of gold (Au), tin (Sn), indium (In), aluminum (Al), silicon (Si), silver (Ag), nickel (Ni) and copper (Cu). It may be formed of a material selected from the group consisting of or alloys thereof.

The reflective layer 140 may be about 2500 angs thick. The reflective layer 140 may include, for example, a metal layer including aluminum (Al), silver (Ag), nickel (Ni), platinum (Pt), rhodium (Rh), or an alloy containing Al, Ag, Pt, or Rh. Can be made. Aluminum or silver may effectively reflect light generated from the active layer 124 to greatly improve the light extraction efficiency of the light emitting device.

Since the light emitting structure 120, in particular, the second conductive semiconductor layer 126 has a low impurity doping concentration and a high contact resistance, and thus may have poor ohmic properties, the ohmic layer 130 may be modified to improve the ohmic characteristics. Can be formed.

The ohmic layer 130 may be about 200 angstroms thick. The ohmic layer 130 may include, for example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), or IGTO (IGTO). indium gallium tin oxide (AZO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IZO (IZO Nitride), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), ZnO , IrOx, RuOx, NiO, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, Ru, Mg, It may be formed including at least one of Zn, Pt, Au, Hf, and is not limited to these materials.

The light emitting structure 120 is formed on the second conductivity-type semiconductor layer 126 and the second conductivity-type semiconductor layer 126 and has an active layer 124 that emits light and a first conductivity-type semiconductor formed on the active layer 124. Layer 122.

The first conductivity type semiconductor layer 122 may be implemented as a group III-V compound semiconductor doped with a first conductivity type dopant, and when the first conductivity type semiconductor layer 122 is an N-type semiconductor layer, The first conductive dopant may be an N-type dopant and may include Si, Ge, Sn, Se, or Te, but is not limited thereto.

The first conductivity-type semiconductor layer 122 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 122 may be formed of any one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP, InP.

Unevenness may be formed on the surface of the light emitting structure 120, that is, the surface of the first conductivity-type semiconductor layer 122 to increase the light extraction effect. In this embodiment, the surface of the first conductivity-type semiconductor layer 122 is increased. Since the light extraction structure 180 is provided at the surface, the unevenness may not be formed on the surface of the first conductivity-type semiconductor layer 122.

The active layer 124 has an energy inherent to a material in which electrons injected through the first conductive semiconductor layer 122 and holes injected through the second conductive semiconductor layer 126 formed thereafter meet each other to form the active layer 124. It is a layer that emits light with energy determined by the band.

The active layer 124 may be formed of at least one of a single quantum well structure, a multi quantum well structure (MQW), a quantum-wire structure, or a quantum dot structure. For example, the active layer 120 may be injected with trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) to form a multi-quantum well structure. It is not limited to this.

The well layer / barrier layer of the active layer 124 may be formed of any one or more pairs of InGaN / GaN, InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, GaAs (InGaAs) / AlGaAs, GaP But are not limited thereto. 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 or under the active layer 124. The conductive clad layer may be formed of an AlGaN-based semiconductor, and may have a higher band gap than the band gap of the active layer 124.

A second conductive semiconductor layer 126 is a second conductive type dopant is doped III-V compound semiconductor, for example _{-5, In x Al y Ga 1 -x-} y N (0≤x≤1, 0≤y≤1 , 0 ≦ x + y ≦ 1). When the second conductive semiconductor layer 124 is a P-type semiconductor layer, the second conductive dopant may be a P-type dopant and may include Mg, Zn, Ca, Sr, and Ba.

In the present exemplary embodiment and other embodiments described later, the first conductive semiconductor layer 122 may be a P-type semiconductor layer, and the second conductive semiconductor layer 126 may be an N-type semiconductor layer. In addition, an N-type semiconductor layer (not shown) may be formed on the second conductive semiconductor layer 126 when the semiconductor having a polarity opposite to that of the second conductive type, for example, the second conductive semiconductor layer is a P-type semiconductor layer. Accordingly, the light emitting structure may be implemented as 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 light extracting structure 180 may be disposed on the light emitting structure 120, in particular, on the first conductive semiconductor layer 122. The light extraction structure 180 includes a nanocavity structure, wherein the second layer 186 is disposed with the first layer 182 having the nano-concave-convex and the nanocavity 184 interposed therebetween. In addition, a transparent conductive layer (not shown) such as ITO may be disposed on the light emitting structure 120, and the light extracting structure 180 may be disposed on the transparent conductive layer.

3A is a detailed view of region 'A' of FIG. 1, and FIG. 3B is a plan view of region 'A' of FIG. 1.

Since the first layer 182 and the second layer 186 may emit light emitted from the active layer 122 to the outside of the light emitting device 100, the first layer 182 and the second layer 186 may be formed of a light transmitting material.

The first layer 182 may be formed of a material having a refractive index of 1.5 to 2.5, and may include an oxide. Specifically, the first layer 182 may include any one of ITO, SiO ₂ , Al ₂ O ₃ , ZnO, TiO ₂ , and polymer. have. The second layer 186 may have the nanocavity 184 therebetween, and any one of ITO, oxide, and epoxy materials may be disposed in the first layer 182, and the same material as the first layer 182 may be disposed. It may be made, or may be made of ZnO as an example of the oxide.

The uneven structure of the first layer 182 includes a concave portion 182a and a convex portion 182b, and the concave portion 182a may be lower than the concave portion 182b. The height of the concave portion 182a is disposed 400 nanometers to 1 micrometer lower than the height of the convex portion 182b, and the above-described height is the depth of the nano concave-convex.

The nano-concave-convex structure formed on the first layer 182 may be formed by a selective deposition or etching method using a mask in addition to the method of nano printing using PDMS (polydimethylsiloxane) as described later.

The cross section of the recessed portion 182a constituting the nano-concave-convex structure may be circular or polygonal as shown in FIG. 3B. When the cross section of the recess 182a is circular, the diameter W ₁ of the cross section of the recess 182a may be 0.1 to 0.5 micrometers. When the cross section of the recess 182a is polygonal, the length of one side of the cross section of the recess 182a may be 0.1 to 0.5 micrometers.

The diameter or the length of one side of the cross section of the concave portion 182a may be referred to as the size of the nano irregularities, and the light emitted from the active layer 124 is extracted when the size of the nano irregularities is smaller than the wavelength of the light emitted from the active layer. Total reflection at the structure 180 can be prevented.

In the nano-concave-convex structure, the concave portion 182a and the convex portion 182b may be regularly arranged in the first layer 182, and the concave portion 182a and the convex portion 182b may have a period P of 0.5 to 0.7 micrometers, respectively. Can be deployed with.

3B is a cross-sectional view taken along the II ′ axis of FIG. 3A, and the period P ₁ in the first direction of each recess 182a and the period P ₂ in the second chamber perpendicular to the first direction are respectively 0.5. FIG. To 0.7 micrometers may be the same as each other.

In FIG. 3A, the height h ₂ of the nanocavity 184 is shown to be lower than the height h ₁ of the recess 182a of the nano unevenness. The depth h ₁ of the concave portion of the nano concave-convex is 200 nanometers to 1 micrometer, and the height h ₂ of the nanocavity 184 may be 80 to 100% of the height h ₁ of the nano concave-convex. That is, the second layer 186 is disposed on the first layer 182 having the nano-concave-convex structure with the nanocavity 184 interposed therebetween. A portion of the second layer 186 may be inserted into the nano-concave-convex structure. The height h ₂ of the nanocavity 184 may be lower than the height h ₁ of the nano-unevenness.

In addition, when the second layer 186 is inserted into the first layer 182, the bottom surface 186a of the second layer 186 facing the recess 182a of the first layer 182 may be It may have a specific angle without being parallel to the recessed portion 182a, and the bottom surface 186a of the second layer 186 may have a curvature. The curvature of the bottom surface 186a of the second layer 186 may be achieved when the second layer 186 is formed by sputtering or electron beam deposition, and the bottom surface of the nanocavity 184 and the second layer 186. An interface of 186 may form a specific angle to increase the light extraction effect of the light emitting device 100.

Although not shown, a first electrode may be formed on the first conductivity type semiconductor layer 122. The first electrode may be formed in a single layer or a multilayer structure including at least one of aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), copper (Cu), and gold (Au). The first electrode may be formed in contact with the first conductivity-type semiconductor layer 122, wherein the light extraction structure is formed covering both the first conductivity-type semiconductor layer 122 and the first electrode, or the first electrode is It may be formed by directly contacting the first conductivity-type semiconductor layer 122 except for the formed region.

In addition, a passivation layer (not shown) may be formed on a side surface of the light emitting structure 120. The passivation layer may be made of an insulating material, and the insulating material may be made of a nonconductive oxide or nitride. For example, the passivation layer may be formed of a silicon oxide (SiO ₂ ) layer, an oxynitride layer, or an aluminum oxide layer.

FIG. 2 is a cross-sectional view of a second embodiment of the light emitting device, FIG. 4A is a detailed view of region 'B' of FIG. 2, and FIG. 4B is a plan view of region 'B' of FIG. 2.

The light emitting device 100 according to the present embodiment is similar to the embodiment shown in FIGS. 1, 3A, and 3B, except that the light extraction structure 180 is directly formed on the first conductive semiconductor layer 122. Do. In FIG. 1, in the light extraction structure 180, the nano unevenness is formed in the first layer 182, but in the present embodiment, the nano unevenness is directly formed in the first conductivity type semiconductor layer 122.

That is, the first conductive semiconductor layer 122 is formed of the recess 122a and the convex portion 122b. The shape and size of the recess 122a and the convex portion 122b may be the same as those described with reference to FIGS. 3A and 3B. have.

The second layer 186 may be formed of any one of ITO, oxide, and epoxy material with the nanocavity 184 therebetween, and may be disposed in the first conductive semiconductor layer 122. In addition, a part of the second layer 186 may be inserted into the nano-convex and concave as in the above-described embodiment.

4B is a cross-sectional view taken along the II ′ axis of FIG. 4A, and the period P ₁ in the first direction of each recess 122a and the period P ₂ in the second direction perpendicular to the first direction are respectively. 0.5 to 0.7 micrometers may be the same as each other.

In FIG. 4A, the height h ₂ of the nanocavity 184 is shown to be lower than the height h ₁ of the nano unevenness 122a. The height h ₂ of the nanocavity 184 may be 80 to 100% of the height h ₁ of the nano-unevenness, as described with reference to FIG. 3A.

5 and 6 are cross-sectional views of the third and fourth embodiments of the light emitting device. 1 and 2 show a vertical light emitting device, while FIGS. 5 and 6 show a lateral light emitting device.

The light emitting device 100 of FIG. 5 includes a substrate 110, a buffer layer 115, a light emitting structure 120, a first electrode 170, and a light extracting structure 180.

The substrate 110 may include a conductive substrate or an insulating substrate, for example, at least one of sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, Si, GaP, InP, Ge, and Ga ₂ 0 ₃ . Can be used.

The buffer layer 115 is intended to mitigate the difference in lattice mismatch and thermal expansion coefficient of the material between the substrate 110 and the light emitting structure 120. The material of the buffer layer 115 may be formed of at least one of Group III-V compound semiconductors, for example, GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN. An undoped semiconductor layer may be formed on the buffer layer 115, but is not limited thereto.

The light emitting structure 120 includes the first conductive semiconductor layer 122, the active layer 124, and the second conductive semiconductor layer 126, as described above. A portion of the first conductivity type semiconductor layer 122 is mesa-etched, but since the electrode cannot be formed under the insulating substrate like the sapphire substrate, the first electrode 170 may be disposed in the above-described etched region. Can be.

The structure of the light extraction structure 180 is the same as the light emitting device shown in FIGS. 1 and 2. However, the light emitting device shown in FIG. 5 contacts the second conductive semiconductor layer 126 and the light extraction pattern 180 ) Is being formed. 6 shows that the nano-convex is formed in the second conductivity-type semiconductor layer 126, and the second layer (with the nanocavity interposed therebetween on the nano-convex structure of the second conductivity-type semiconductor layer 126). 186 is disposed.

The light extraction structures of FIGS. 5 and 6 are the same as the light extraction structures of the light emitting devices of FIGS. 1 and 2, respectively.

7A to 7H are diagrams illustrating a first embodiment of a method of manufacturing a light emitting device.

As shown in FIG. 7A, a light emitting structure 120 including a buffer layer 115, a first conductivity type semiconductor layer 122, an active layer 124, and a second conductivity type semiconductor layer 126 on a substrate 110. Grow).

The light emitting structure 120 may include, for example, Metal Organic Chemical Vapor Deposition (MOCVD), Chemical Vapor Deposition (CVD), Plasma-Enhanced Chemical Vapor Deposition (PECVD), and molecular beam growth. It may be formed using a method such as Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), but is not limited thereto.

The substrate 110 may include a conductive substrate or an insulating substrate, and for example, may use at least one of sapphire (Al ₂ O ₃ ), SiC, GaAs, GaN, ZnO, Si, GaP, InP, Ge, and Ga ₂ 0 ₃ . have. An uneven structure may be formed on the substrate 110, but is not limited thereto. The substrate 110 may be wet-cleaned to remove impurities on the surface.

The buffer layer 115 may be grown between the light emitting structure 120 and the substrate 110 to mitigate the difference in lattice mismatch and thermal expansion coefficient of the material. The material of the buffer layer 115 may be formed of at least one of Group III-V compound semiconductors, for example, GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN. An undoped semiconductor layer may be formed on the buffer layer 115, but is not limited thereto.

The light emitting structure 120 may be grown by vapor deposition such as metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and hydraulic vapor phase epitaxy (HVPE).

The composition of the first conductive semiconductor layer 122 is the same as described above, and is N-type using a method such as chemical vapor deposition (CVD) or molecular beam epitaxy (MBE) or sputtering or hydroxide vapor phase epitaxy (HVPE). A GaN layer can be formed. In addition, the first conductive semiconductor layer 110 may include a silane including n-type impurities such as trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and silicon (Si) in the chamber. The gas SiH ₄ may be injected and formed.

The active layer 124 has the same composition as described above. For example, the trimethyl gallium gas (TMGa), the ammonia gas (NH ₃ ), the nitrogen gas (N ₂ ), and the trimethyl indium gas (TMIn) are injected to form a multiple quantum. A well structure may be formed, but is not limited thereto.

The second conductive semiconductor layer 126 has the same composition as described above, and has a p-type such as trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and magnesium (Mg) in the chamber. Bicetyl cyclopentadienyl magnesium (EtCp ₂ Mg) {Mg (C ₂ H ₅ C ₅ H ₄ ) ₂ } including impurities may be implanted to form a p-type GaN layer, but is not limited thereto.

As shown in FIG. 7B, an ohmic layer 130 and a reflective layer 140 may be formed on the light emitting structure 120. The composition of the ohmic layer 130 and the reflective layer 140 is as described above, and may be formed by sputtering or electron beam deposition.

As illustrated in FIG. 7C, the bonding layer 150 and the conductive support substrate 160 may be formed on the reflective layer 140. The conductive support substrate 170 may be formed using an electrochemical metal deposition method, a bonding method using an etchant metal, or a separate bonding layer 150.

Then, the substrate 110 is separated as shown in FIG. 7D. The substrate 110 may be removed by a laser lift off (LLO) method using an excimer laser or the like, or may be a method of dry and wet etching.

For example, when the laser lift-off method focuses and irradiates excimer laser light having a predetermined wavelength in the direction of the substrate 110, heat energy is applied to the interface between the substrate 110 and the light emitting structure 120. As the interface is concentrated and separated into gallium and nitrogen molecules, the substrate 110 may be momentarily separated from a portion where the laser light passes, and the buffer layer 115 may be separated together.

In addition, each light emitting structure 120 may be diced by element.

As illustrated in FIG. 7E, the first layer 182 is stacked on the surface of the first conductivity-type semiconductor layer 122, and may be stacked by spin coating or the like. In this case, the material of the first layer 182 may be an imprint resin or a sol-gel solution in which nanoparticles such as TiO ₂ , ZnO, and Al ₂ O ₃ are dispersed.

As shown in FIG. 7F, nano irregularities are formed on the surface of the first layer 182. In this case, the nano-pattern 200 may press the first layer 182 to form nano-concave-convex on the surface of the first layer 182. The nano-pattern 200 is made of a material such as PDMS, and a nano-pattern is formed on the surface, and the nano-pattern of the nano-pattern 200 is transferred to the first layer 182 and nano-on the first layer 182. Unevenness may be formed. The nano irregularities may be formed of recesses and convex portions as described in FIG. 1.

In FIG. 7G, the nano-pattern 200 is removed and a deposition material is deposited on the surface of the first layer 182. The deposition material is the material of the second layer 186 of FIG. 1, and the deposition material covers the nano irregularities of the first layer 182 with the nanocavity interposed therebetween.

In FIG. 7H, the light extraction structure 180 is shown in which the deposition material covers the first layer 182 to form the second layer 186. At this time, the deposition material is deposited with the recess 182a and the nanocavity 184 differently in the nano-concave of the first layer 182 to form the second layer 186, and the first layer 182 and the first layer 182 are formed. The two layers 186 are disposed with the nanocavity 184 therebetween to form the light extraction structure 180.

8A to 8D show a second embodiment of the manufacturing method of the light emitting device. 7A to 7H, the nano-convexity is formed after the first layer 182 is disposed on the surface of the light emitting structure 120. However, in the present exemplary embodiment, the first layer 182 having the nano-convexity is formed. After preparing in advance, the first layer 182 is disposed on the surface of the first conductivity-type semiconductor layer 1222.

That is, in FIG. 8A, the first layer 182 is deposited on the surface of the nanopattern 200 by spin coating or the like. The material of the first layer 182 is as described above, and the uneven structure of the nanopattern 200 is transferred and formed on the surface of the first layer 182.

In FIG. 8B, the first layer 182 is disposed on the surface of the first conductivity type semiconductor layer 122.

In FIG. 8C, the nano-pattern 200 is removed and a deposition material is deposited on the surface of the first layer 182. The deposition material is the material of the second layer 186 of FIG. 1, and the deposition material covers the nano irregularities of the first layer 182.

In FIG. 8D, a light extraction structure 180 is shown in which the deposition material covers the first layer 182 to form the second layer 186. At this time, the deposition material is deposited with the recess 182a and the nanocavity different from each other in the nano-concave of the first layer 182 to form the second layer 186, and the first layer 182 and the second layer ( 186 is disposed with the nanocavity 184 therebetween to form the light extraction structure 180.

9A to 9C are diagrams illustrating a third embodiment of a method of manufacturing a light emitting device. The embodiment includes a process of manufacturing a light emitting device in which nano irregularities are formed on the surface of the first conductivity type semiconductor layer 122.

As illustrated in FIG. 9A, nano irregularities are formed on the surface of the first conductivity-type semiconductor layer 122 using the mask 210. In FIG. 9A, the preparation process before forming the nano irregularities using the mask 210 is the same as the process illustrated in FIGS. 7A to 7D.

The surface of the first conductivity type semiconductor layer 122 is selectively etched using the mask 210 to form nano irregularities. The structures and shapes of the recesses and convex portions of the nano irregularities are as described with reference to FIGS. 3A and 3B. Selective etching of the surface of the first conductive semiconductor layer 122 may be performed by dry etching or wet etching using an etchant.

In FIG. 9B, a second material may be formed by depositing a deposition material on a surface of the first conductivity-type semiconductor layer 122 on which nano irregularities are formed.

FIG. 9C illustrates a light emitting device in which the second layer 186 is disposed with the nanocavities 184 interposed between the nano-convexities of the first conductivity-type semiconductor layer 122 and the light extraction structure 180 is formed.

10A to 10F illustrate a fourth embodiment of the method of manufacturing a light emitting device.

First, as shown in FIG. 10A, a first layer 182 and a photo resist 220 are disposed on a surface of the first conductivity-type semiconductor layer 122. The preparation process before disposing the first layer 182 and the photoresist 220 is the same as the process illustrated in FIGS. 7A to 7D.

As shown in FIGS. 10B and 10C, a portion of the photoresist 220 is removed to form a pattern. The photoresist 220 is used as a medium for forming nano irregularities in the first layer 182. As shown in FIG. 10B, irregularities may be formed in the photoresist 220, such as photolithography. Part of the photoresist 220 may be removed by the method.

As shown in FIG. 10C, the photoresist 220 may be patterned by removing the recesses from the photoresist 220 in which the recesses and the convex portions are formed in FIG. 10B. In this process, a dry etching method using an oxygen plasma may be used to remove the recessed portions of the photoresist 220.

And, as shown in FIG. 10D, a portion of the first layer 182 may be removed using the patterned photoresist 220 to form nano irregularities. In this case, the first layer 182 may be removed by plasma etching or wet etching using Cl ₂ , BCl ₃ , CF ₄ , Ar, O ₂ , or the like.

In FIG. 10E, the photoresist 220 is removed and a deposition material is deposited on the surface of the first layer 182. The deposition material is the material of the second layer 186 of FIG. 1, and the deposition material covers the nano irregularities of the first layer 182.

In FIG. 10F, a light extraction structure 180 is shown in which the deposition material covers the first layer 182 to form the second layer 186. At this time, the deposition material is deposited with the recess 182a and the nanocavity 184 differently in the nano-concave of the first layer 182 to form the second layer 186, and the first layer 182 and the first layer 182 are formed. The two layers 186 are disposed with the nanocavity 184 therebetween to form the light extraction structure 180.

11 is a view showing the operation of the light emitting device according to the embodiment.

In the active layer 124, electrons injected through the first conductive semiconductor layer 122 and holes injected through the second conductive semiconductor layer 126 meet each other to form an active layer 124. Emits light with the energy to be determined. The light emitted from the active layer 124 may be visible light or ultraviolet light, and particularly may be ultraviolet light having a wavelength of 365 nanometers or less.

The light passing through the first conductivity-type semiconductor layer 122 among the lights illustrated by the dotted lines passes through the light extraction structure 180 and may have an extended angle. That is, light is refracted by the difference in refractive index at the interface between the first layer 182, the nanocavity 184, and the second layer 186 within the light extraction structure 180. In particular, when the nanocavity 184 is formed to a size smaller than the wavelength of light emitted from the active layer 124, it is possible to prevent total reflection of light by the nanocavity.

In the case where there is no nanocavity structure, the light extraction device may decrease light extraction efficiency due to the total reflection of light on the surface of the light emitting structure, etc. The light emitting device according to the above-described embodiments may be caused by an air gap. As the volume of the nanocavity increases, the total reflection decrease and the light scattering effect may increase.

12A and 12B show a light extraction structure of the light emitting device.

12A shows that a polymer is patterned with a nano-concave-convex structure on top of ITO to form a first layer, and ZnO is deposited on the polymer by sputtering, and a nano void is formed between the polymer and ZnO. It is becoming.

12B shows that a polymer is patterned with a nano-concave-convex structure on top of ITO to form a first layer, and ITO is deposited on the polymer by sputtering, and a nano void is formed between the polymer and ITO. It is becoming.

13 is a view showing an embodiment of a light emitting device package.

The light emitting device package 300 according to the embodiment includes a package body 310, a first lead frame 221 and a second lead frame 222 installed on the package body 310, and the package body 310. The light emitting device 100 is installed and electrically connected to the first lead frame 221 and the second lead frame 222, and a molding part 350 covering the surface or the side surface of the light emitting device 100. do.

The package body 310 may include a silicon material, a synthetic resin material, or a metal material. An inclined surface may be formed around the light emitting device 100 to increase light extraction efficiency.

The first lead frame 221 and the second lead frame 222 are electrically separated from each other, and provide power to the light emitting device 100. In addition, the first lead frame 221 and the second lead frame 222 may increase the light efficiency by reflecting the light generated by the light emitting device 100, heat generated by the light emitting device 100 It may also play a role in discharging it to the outside.

The light emitting device 100 may be installed on the package body 310 or on the first lead frame 321 or the second lead frame 322. The light emitting device 100 may be electrically connected to the first lead frame 321 and the second lead frame 322 by any one of a wire method, a flip chip method, or a die bonding method. In the present exemplary embodiment, the light emitting device 100 is connected to the first lead frame 321 and the conductive adhesive layer 330 and is bonded to the second lead frame 322 and the wire 340.

The molding part 350 may surround and protect the light emitting device 100. In addition, the maldium 350 may include a phosphor 355 to change the wavelength of the light emitted from the light emitting device 100.

In the light emitting device package 300 according to the embodiment, the light extraction structure may be disposed in the light emitting device 100 to improve the light extraction characteristics.

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

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

14 is a view showing an embodiment of a head lamp including a light emitting device package.

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

As described above, since the light extraction efficiency of the light emitting device used in the light emitting device module 401 can be improved, the optical characteristics of the entire head lamp can be improved.

The light emitting device package included in the light emitting device module 401 may include a plurality of light emitting devices, but is not limited thereto.

15 is a diagram illustrating an embodiment of a display device including a light emitting device package.

As shown, the display device 500 according to the present exemplary embodiment includes a light source module, a reflector 520 on the bottom cover 510, and a light disposed in front of the reflector 520 and emitting light emitted from the light source module. In front of the light guide plate 540, the first prism sheet 550 and the second prism sheet 560 disposed in front of the light guide plate 540, and in front of the second prism sheet 560. And a color filter 580 disposed throughout the panel 570.

The light source module comprises a light emitting device package 535 on a circuit board 530. Here, a circuit board (PCB) may be used as the circuit board 530, and the light emitting device package 535 is as described with reference to FIG. 13.

The bottom cover 510 may accommodate components in the display device 500. The reflective plate 520 may be formed as a separate component as shown in the drawing, or may be provided on the rear surface of the light guide plate 540 or on the front surface of the bottom cover 510 with a highly reflective material.

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

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

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

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

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

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

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

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

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

In the display device 500 according to the exemplary embodiment, the light extraction efficiency of the light emitting device used for the light emitting device package 535 may be improved, and thus the optical characteristics of the display device may be improved.

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

100 light emitting element 110 substrate
115: buffer layer 120: light emitting structure
122: first conductive semiconductor layer 124: active layer
126: second conductive semiconductor layer 130: ohmic layer
140: reflective layer 150: bonding layer
160: conductive support substrate 170: first electrode
180: light extraction structure 182: first layer
182a, 182b: recessed part and iron part 184: nano cavity
186: second layer 200: nano-pattern
210: mask 220: photoresist
300: light emitting device package 310: package body
321: first lead frame 322: second lead frame
330: conductive adhesive layer 340: wire
350 molding unit 360 phosphor
400: head lamp 410: light emitting element module
420: reflector 430: shade
440 lens
800: display device 810: bottom cover
820: reflector 830: circuit board module
840: Light guide plate 850, 860: First and second prism sheet
870 panel 880 color filter

Claims (21)

A light emitting structure including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer; And
A light emitting device comprising a light extraction structure disposed on the light emitting structure and including a nano cavity. The method of claim 1, wherein the light extraction structure,
A light emitting device comprising: a first layer having nanoconcave-convex formation and a second layer disposed on the first layer with a nanocavity therebetween. The method of claim 1, wherein the light extraction structure,
A light emitting device in which nano irregularities are formed in a first conductive semiconductor layer or a second conductive semiconductor layer, and a second layer is disposed between the nano irregularities and the nanocavity. The method according to claim 2 or 3,
The second layer is a light emitting device in which at least a portion is inserted into the nano irregularities. The method of claim 2, wherein the first layer,
Light emitting device comprising an oxide. The method of claim 2, wherein the first layer,
A light emitting device comprising any one of ITO, SiO ₂ , Al ₂ O ₃ , ZnO, TiO ₂ , and a polymer. The method according to claim 2 or 3,
The nano unevenness is a light emitting device having a depth of 400 nanometers to 1 micrometer. The method according to claim 2 or 3,
The cross-section of the nano-evenness is circular, the light-emitting device of the nano-evenness is 0.1 micrometer to 0.5 micrometer in diameter of the cross section. The method according to claim 2 or 3,
The nano unevenness is smaller than the wavelength of light emitted from the active layer light emitting device. The method according to claim 2 or 3,
The nano irregularities are regularly arranged light emitting device. The method according to claim 2 or 3,
The nano unevenness is a light emitting device having a period of 0.5 to 0.7 micrometers. The method according to claim 2 or 3,
The second layer is any one of ITO, oxide, epoxy material. The method according to claim 2 or 3,
The light emitting device of which the height of the nanocavity is smaller than the depth of the nano irregularities. The method according to claim 2 or 3,
The height of the nano cavity is 80 to 100% of the height of the nano unevenness. The method according to claim 2 or 3,
The cross section of the nanocavity is circular, the diameter of the cross section of the nanocavity is 0.1 micrometer to 0.5 micrometer light emitting device. The method according to claim 2 or 3,
The first layer has a refractive index of 1.5 to 2.5 light emitting device. The method of claim 2,
The first layer is a light emitting device made of the same material as the second layer. The method of claim 2,
And the bottom surface of the second layer is not parallel to the bottom surface of the recessed portion of the first layer. The method of claim 3, wherein
And a bottom surface of the second layer is not parallel to a bottom surface of a recess of the first conductive semiconductor layer or the second conductive semiconductor layer. The method of claim 2,
And the first layer is in contact with the second conductive semiconductor layer. The method of claim 1,
The light emitting structure is a light emitting device for generating light of the wavelength of the ultraviolet region.

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