KR20120078049A - Light emitting diode and method for fabricating the light emitting device - Google Patents

Abstract

PURPOSE: A light emitting diode and a manufacturing method thereof are provided to improve the reliability of a light emitting device by increasing an adhesive force between a second electrode and a current blocking layer. CONSTITUTION: A light emitting structure(120) includes a first conductive semiconductor layer, an active layer(124), and a second conductive semiconductor layer. A second electrode(155) is formed on a lower portion of the light emitting structure and includes a first area, which is touched with the light emitting structure, and a second area excluding the first area. A barrier layer is formed between the light emitting structure and the second area. The barrier layer includes an uneven shape on a side which is adjacent to the second electrode.

Description

Light emitting device and method for manufacturing the light emitting device {Light emitting diode and method for fabricating the light emitting device}

Embodiments relate to a light emitting device that enhances the adhesion of the light emitting device to improve stability and reliability.

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 white light emitting device that can replace a fluorescent light bulb or an incandescent bulb that replaces a Cold Cathode Fluorescence Lamp (CCFL) constituting a backlight of a transmission module of an optical communication means and a liquid crystal display (LCD) display device. Applications are expanding to diode lighting devices, automotive headlights and traffic lights.

The stability and reliability of such a light emitting device is a very important factor, it is necessary to improve the stability and reliability of the light emitting device.

Embodiments relate to a light emitting device that improves the bonding strength of the light emitting device to improve the stability and reliability.

Embodiments include a light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer; A second electrode formed under the light emitting structure and including a first region in contact with the light emitting structure and a second region except for the first region; And a barrier layer formed between the light emitting structure and the second region, wherein the barrier layer includes a concave-convex structure on a surface adjacent to the second electrode.

At this time, the step from the valley to the floor of the uneven structure may be formed in 0.01 ~ 0.5㎛.

In addition, the uneven structure may be formed on the second region.

In addition, the second electrode may include at least one of an ohmic layer, a reflective layer, and a bonding layer.

In addition, the ohmic layer may be formed on at least a part of the uneven structure, and the reflective layer may be formed on the rest of the uneven structure.

In addition, the barrier layer may include at least one of a channel layer and a current limiting layer.

In addition, the channel layer may include an uneven structure on a surface adjacent to the second electrode, and the current limiting layer may not include the uneven structure.

In addition, the light emitting device may include at least one first electrode formed to partially overlap the barrier layer on the light emitting structure.

The light emitting device may further include a conductive layer formed under the second electrode.

In addition, the conductive layer may include at least one protrusion toward the light emitting structure.

In addition, the second electrode may surround the at least one protrusion included in the conductive layer.

The light emitting device according to the embodiment has the effect of improving the bonding strength to improve the stability and reliability.

1 is a view showing an embodiment of a light emitting device,
2A to 2K are views illustrating a method of manufacturing an embodiment of a light emitting device;
3 is a view illustrating an embodiment in which a concave-convex structure is formed in the barrier layer, and a second electrode is formed in the concave-convex structure;
4 is a view showing another embodiment in which the uneven structure is formed in the barrier layer, and the second electrode is formed in the uneven structure;
5 is a view showing an embodiment of a light emitting device package.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In the description of the above embodiments, each layer (region), region, pattern or structures may be "on" or "under" the substrate, each layer (layer), region, pad or pattern. In the case of what is described as being formed, "on" and "under" include both being formed "directly" or "indirectly" through another layer. In addition, the criteria for the top or bottom of each layer will be described with reference to the drawings.

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

1 is a cross-sectional view of an embodiment of a light emitting device.

As shown in FIG. 1. The light emitting device of the first embodiment includes a bonding layer 150 formed on the support substrate 160, a conductive layer 170 formed on the bonding layer 150, and a second electrode 155 formed on the conductive layer 170. And a current limiting layer 135 and a channel layer 180 formed on the second electrode 155, a first conductive semiconductor layer 122, an active layer 124, and a second conductive semiconductor layer 126. The light emitting structure 120 may include a first electrode 190 formed on the first conductive semiconductor layer 122. Here, the current limiting layer 135 and the channel layer 180 formed on the second electrode 155 may be defined as a barrier layer. In addition, the second electrode 155 may include at least one of the ohmic layer 130 and the reflective layer 140.

As illustrated, the light emitting device may have a second electrode 155 formed on the coupling layer 150, the conductive layer 170, and the conductive layer 170 on the support substrate 160.

The support substrate 160 may be made of a material selected from the group consisting of molybdenum (Mo), silicon (Si), tungsten (W), copper (Cu), and aluminum (Al) or alloys thereof. For example, gold (Au), copper alloy (Cu Alloy), nickel (Ni-nickel), 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. The conductive support substrate 160 may be formed using an electrochemical metal deposition method or a bonding method using a eutectic metal.

In addition, the bonding layer 150 may be formed on the support substrate 160 to be bonded to the conductive layer 170. The bonding layer 150 is, for example, from the group consisting of gold (Au), tin (Sn), indium (In), silver (Ag), nickel (Ni), niobium (Nb) and copper (Cu). It may be formed of the material selected or alloys thereof.

The conductive layer 170 is a material selected from the group consisting of nickel (Ni-nickel), platinum (Pt), titanium (Ti), tungsten (W), vanadium (V), iron (Fe), and molybdenum (Mo). Or they may be made of an alloy optionally included.

The conductive layer 170 has an effect of minimizing mechanical damage (breaking or peeling, etc.) that may occur in the manufacturing process of the light emitting device. In addition, the conductive layer 170 has an effect of preventing the metal material constituting the support substrate 160 or the bonding layer 150 from being diffused into the light emitting structure 120.

In addition, according to an embodiment, the conductive layer 170 may include at least one protrusion toward the light emitting structure to improve the bonding strength of the light emitting device. In this case, the second electrode 155 may surround the protrusion included in the conductive layer.

The second electrode 155 may be formed on the conductive layer. The second electrode 155 may include at least one of the reflective layer 140 and the ohmic layer 130.

The second electrode 155 may be formed in a layer or a plurality of patterns under the second conductive semiconductor layer 126 for ohmic contact, and may be ohmic contact with a reflective metal or ohmic contact using a conductive oxide. .

The second electrode 155 may be formed of the metal, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), and IGTO (IGTO). among indium gallium tin oxide (AZO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrOx, RuOx, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO It may include at least one, but is not limited to such materials.

In addition, the second electrode 155 may be made of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, and a selective combination thereof. In addition, the second electrode 155 may be formed as a single layer or multiple layers of a reflective electrode material having ohmic characteristics.

In addition, the second electrode 155 may include a bonding layer (not shown), wherein the bonding layer (not shown) may be a barrier metal or a bonding metal such as Ti, Au, Sn, and Ni. It may include at least one of Cr, Ga, In, Bi, Cu, Ag or Ta.

The second electrode 155 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.

The reflective layer 140 is made of a metal layer including aluminum (Al), silver (Ag), nickel (Ni), platinum (Pt), rhodium (Rh), or an alloy containing Al, Ag, Pt, or Rh, It may be formed in multiple layers using the metal material and light transmitting conductive materials such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, and ATO. In addition, the reflective layer 140 may be laminated with IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni, or the like. In addition, when the reflective layer 140 is formed of a material in ohmic contact with the light emitting structure (eg, the second conductivity-type semiconductor layer 126), the ohmic layer 130 may not be separately formed, but is not limited thereto. The reflective layer 140 may effectively reflect the light generated by the active layer 124 to greatly improve the light extraction efficiency of the light emitting device.

The ohmic layer 130 is in ohmic contact with a lower surface of the light emitting structure (eg, the second conductivity-type semiconductor layer 126), and may be formed in a layer or a plurality of patterns. The ohmic layer 130 may be selectively formed of a light transmissive conductive layer and a metal, and may be stacked to a thickness of about 200 angstroms. The ohmic layer 130 may selectively use a light transmissive conductive layer and a metal. For example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), and indium aluminum zinc (AZO) oxide), IGZO (indium gallium zinc oxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (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, Zn, Pt, Au, can be formed including at least one of Hf, and is not limited to these materials. The ohmic layer 130 may be formed by sputtering or electron beam deposition.

The second electrode 155 may be formed under the light emitting structure 120, and may include a first region in contact with the light emitting structure 120 and a second region except for the first region.

A barrier layer, that is, a current limiting layer 135 or a channel layer 180, may be formed between the light emitting structure 120 and the second region of the second electrode 155. In this case, the barrier layer may include a concave-convex structure on a surface adjacent to the second electrode.

The current limiting layer 135 of the barrier layer distributes the flow of current flowing to the light emitting structure 120 in the horizontal direction, thereby preventing malfunction of the light emitting device due to overcurrent, thereby increasing stability and reliability of the light emitting device. .

The current limiting layer 135 may be formed between the second electrode 155 and the light emitting structure 120. The current limiting layer 135 is formed using a metal, a material having a lower electrical conductivity than the reflective layer 140, a material forming a Schottky contact with the second conductive semiconductor layer 126, or an electrically insulating material. Can be. For example, the current limiting layer 135 is formed of ZnO, SiO ₂ , SiON, It may include at least one of Si ₃ N ₄ , Al ₂ O _3, TiO ₂ , Ti, Al, Cr.

The current limiting layer 135 may include an uneven structure formed on a surface adjacent to the second electrode 155. At this time, the uneven structure may be formed periodically or aperiodic, the uneven shape is not limited. For example, the concave-convex shape includes all shapes of single or complex shapes such as square, hemisphere, triangle, and trapezoid.

The uneven structure may be formed using a wet etching process or a dry etching process, or may be formed using a wet etching process and a dry etching process.

The dry etching method may be plasma etching, sputter etching, ion etching, etc., and the wet etching process may be a PEC (Photo Chemical Wet-etching) process.

In this case, in the PEC process, the shape of the irregularities having a fine size may be controlled by controlling the etching rate difference due to the amount of the etchant and the crystallinity of the material forming the current limiting layer 135. After the mask is formed, the uneven shape may be periodically adjusted through etching.

According to an embodiment, the step from the floor to the valley of the uneven structure may be formed in various ranges of values, for example, may be formed in 0.01 ~ 0.5㎛.

The second electrode 155 may be formed under the uneven structure of the current limiting layer 135. In some embodiments, the ohmic layer 130 and the reflective layer 135 constituting the second electrode 155 may be sequentially formed under the uneven structure of the current limiting layer 135.

For example, the ohmic layer 130 may be formed on at least a portion of the uneven structure, and the reflective layer 140 may be formed on the rest of the uneven structure.

Therefore, in the embodiment, the current limiting layer 135 includes an uneven structure formed on a surface adjacent to the second electrode 155, and since the second electrode 155 is formed under the uneven structure, the current limiting layer 135 is formed. ) And the adhesion between the second electrode 155 and the second electrode 155 to prevent mechanical damage (for example, peeling) of the light emitting device due to the weakening of the adhesive force between the current limiting layer 135 and the second electrode 155, and By minimizing the mechanical damage of the device, there is an effect that can increase the stability and reliability of the light emitting device.

The channel layer 180 of the barrier layer may include at least one of a metal material and an insulating material. In the case of the metal material, the channel layer 180 may be formed of a material having lower electrical conductivity than the material forming the ohmic layer 130. ) May not be applied to the channel layer 180.

For example, the channel layer 180 may include at least one of titanium (Ti), nickel (Ni), platinum (Pt), lead (Pb), rhodium (Rh), iridium (Ir), and tungsten (W). Or at least one of aluminum oxide (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ), and titanium oxide (TiO _x ), or indium tin oxide (ITO) ), Aluminum zinc oxide (AZO) and indium zinc oxide (IZO, Indium Zinc Oxide) may include at least one, preferably titanium (Ti), nickel (Ni), platinum (Pt), It may include at least one of tungsten (W), molybdenum (Mo), vanadium (V), iron (Fe). In some embodiments, the channel layer 180 may be formed of the same material as the material forming the current limiting layer 135.

When the light emitting structure 120 is etched, the channel layer 180 protects the components disposed under the channel layer 180 from etching, and stably supports the light emitting device to protect against damages that may occur in the manufacturing process. .

In some embodiments, the channel layer 180 may include an uneven structure formed on a surface adjacent to the second electrode 155. At this time, the uneven structure may be formed periodically or aperiodic, the uneven shape is not limited. For example, the concave-convex shape includes all shapes of single or complex shapes such as square, hemisphere, triangle, and trapezoid.

The uneven structure may be formed using a wet etching process or a dry etching process, or may be formed using a wet etching process and a dry etching process.

The dry etching method may be plasma etching, sputter etching, ion etching, etc., and the wet etching process may be a PEC (Photo Chemical Wet-etching) process.

At this time, in the PEC process, by adjusting the amount of the etchant and the etching speed difference due to the crystallinity of the material constituting the channel layer 180, the shape of the irregularities of the fine size can be adjusted. After the mask is formed, the uneven shape may be periodically adjusted through etching.

At this time, the step from the floor to the valley of the uneven structure may be formed in 0.01 ~ 0.5㎛.

The second electrode 155 may be formed under the uneven structure of the channel layer 180. In this case, the ohmic layer 130 and the reflective layer may be sequentially formed below the uneven structure of the channel layer 180.

Accordingly, in an embodiment, the channel layer 180 includes an uneven structure formed on a surface adjacent to the ohmic layer 130 or the reflective layer 140, and the ohmic layer 130 or the reflective layer 140 is formed under the uneven structure. Therefore, by improving the bonding force between the current limiting layer 135 and the ohmic layer 130 or the reflective layer 140, the light emitting device due to the weakening of the adhesive force between the current limiting layer 135 and the ohmic layer 130 or the reflective layer 140 By preventing the mechanical damage (for example, peeling) of the, and by minimizing the mechanical damage of the light emitting device, there is an effect that can increase the stability and reliability of the light emitting device.

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 the first conductivity type semiconductor layer 112 may be an N-type semiconductor layer. In this case, the first conductivity type dopant may be an N type dopant and may include Si, Ge, Sn, Se, Te, but is not limited thereto.

In addition, the active layer 124 may be formed by integrating electrons injected through the first conductivity-type semiconductor layer 122 and holes injected through the second conductivity-type semiconductor layer 126 that are formed thereafter to form an active layer (light emitting layer) material. It is a layer that emits light with energy determined by the energy band.

The second conductivity-type semiconductor layer 126 may be a Group III _- V compound semiconductor doped with a second conductivity type dopant, for example, In _x Al _y Ga _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ And 1, 0 ≦ x + y ≦ 1). When the second conductive semiconductor layer 126 is a P-type semiconductor layer, the second conductive dopant may include Mg, Zn, Ca, Sr, Ba, and the like as a P-type dopant.

An uneven structure is formed on the first conductive semiconductor layer 122 to improve light extraction efficiency. In this case, the uneven structure may be formed by using a dry etching process or by etching after forming a PEC method or a mask. The dry etching method may be used such as plasma etching, sputter etching, ion etching and the like.

The uneven structure of the light emitting structure changes the incident angle of and emitted from the active layer 124 to the first conductivity type semiconductor layer 122 to reduce the total reflection on the surface of the first conductivity type semiconductor layer 122 to extract light. The effect can be increased, and the luminous efficiency of the light emitted from the active layer 124 can be reduced by reducing the absorption of the light in the light emitting structure.

The uneven structure may be formed periodically or aperiodically, and the uneven shape is not limited. For example, the concave-convex shape includes all shapes of single or complex shapes such as square, hemisphere, triangle, and trapezoid.

The uneven structure may be formed using a wet etching process or a dry etching process, or may be formed using a wet etching process and a dry etching process.

The dry etching method may be plasma etching, sputter etching, ion etching, etc., and the wet etching process may be a PEC (Photo Chemical Wet-etching) process.

At this time, in the case of the PEC process, by adjusting the amount of the etching liquid (eg, KOH) and the etching rate difference by the GaN crystallinity, it is possible to control the shape of the irregularities of the fine size. After the mask is formed, the uneven shape may be periodically adjusted through etching.

In addition, a first electrode 190 is formed on the first conductive semiconductor layer 122, and the first electrode 190 is formed of molybdenum (Mo), chromium (Cr), nickel (Ni), and gold (Au). , Aluminum (Al), titanium (Ti), platinum (Pt), vanadium (V), tungsten (W), lead (Pd), copper (Cu), rhodium (Rh) and iridium (Ir) It consists of a metal or an alloy of these metals.

Detailed description of each configuration will be described in detail with reference to FIGS. 2A to 2G.

2A to 2G illustrate a method of manufacturing an embodiment of a light emitting device.

The substrate 100 is prepared as shown in FIG. 2A. The substrate 100 may be formed of a conductive substrate or an insulating substrate. For example, sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, Si, GaP, InP, Ge, and Ga ₂ 0 At least one of _three may be used. An uneven structure may be formed on the substrate 100, but is not limited thereto. Impurities on the surface may be removed by wet cleaning the substrate 100.

In addition, the light emitting structure 120 including the first conductive semiconductor layer 122, the active layer 124, and the second conductive semiconductor layer 126 may be formed on the substrate 100.

In this case, a buffer layer (not shown) may be grown between the light emitting structure 120 and the substrate 100 to mitigate the difference in lattice mismatch and thermal expansion coefficient of the material. The material of the buffer layer may be made of a group III-V compound semiconductor, and for example, may be formed of at least one of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN. An undoped semiconductor layer may be formed on the buffer layer, but is not limited thereto.

In addition, the light emitting structure 120 may include, for example, a metal organic chemical vapor deposition (MOCVD), a chemical vapor deposition (CVD), or a plasma chemical vapor deposition (PECVD). ), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), and the like, but are not limited thereto.

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 112 is an N-type semiconductor layer, The first conductive dopant may be an N-type dopant, and may include, for example, Si, Ge, Sn, Se, or Te.

The first conductive semiconductor layer 122 may be formed of 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). It may include. For example, the first conductive semiconductor layer 112 may be formed of any one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP, InP. Can be.

The first conductive semiconductor layer 122 may include a silane gas containing n-type impurities such as trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and silicon (Si) in the chamber. SiH ₄ ) may be implanted.

The active layer 124 has energy determined by an energy band inherent in the active layer (light emitting layer) material because carriers injected through the first conductive semiconductor layer 122 and the second conductive semiconductor layer 126 meet each other. It is a layer that emits light.

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 114 may be formed by injecting 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 has a pair structure of at least one of InGaN / GaN, InGaN / InGaN, GaN / AlGaN /, InAlGaN / GaN, GaAs (InGaAs), / AlGaAs, GaP (InGaP) / AlGaP. It may be formed, but is not limited thereto. The well layer may be formed of a material having a band gap narrower than the band gap of the barrier layer.

A conductive cladding 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 band gap higher than that of the active layer 124.

The second conductivity-type semiconductor layer 126 may be a Group III-V compound semiconductor doped with a second conductivity type dopant, for example, In _x Al _y Ga _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, Semiconductor material having a composition formula of 0 ≦ x + y ≦ 1). When the second conductivity type semiconductor layer 126 is a P type semiconductor layer, the second conductivity type dopant may include Mg, Zn, Ca, Sr, Ba, or the like as a P type dopant.

The second conductivity type semiconductor layer 126 is a bicetyl cyclone containing p-type impurities such as trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and magnesium (Mg) in the chamber. Pentadienyl magnesium (EtCp ₂ Mg) {Mg (C ₂ H ₅ C ₅ H ₄ ) ₂ } may be injected to form a p-type GaN layer, but is not limited thereto.

In an embodiment, 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. have. Accordingly, the light emitting structure 110 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.

As shown in FIG. 2B, a barrier layer, that is, a current limiting layer 135 or a channel layer 180 is formed on the second conductive semiconductor layer 126.

The channel layer 180 may include at least one of a metal material and an insulating material. In the case of the metal material, the channel layer 180 is applied to the ohmic layer 130 using a material having a lower electrical conductivity than the material forming the ohmic layer 130. It is possible to prevent the current from being applied to the channel layer 180.

For example, the channel layer 180 may include at least one of titanium (Ti), nickel (Ni), platinum (Pt), lead (Pb), rhodium (Rh), iridium (Ir), and tungsten (W). Or at least one of aluminum oxide (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ), and titanium oxide (TiO _x ), or indium tin oxide (ITO) ), Aluminum zinc oxide (AZO) and indium zinc oxide (IZO, Indium Zinc Oxide) may include at least one, preferably titanium (Ti), nickel (Ni), platinum (Pt), It may include at least one of tungsten (W), molybdenum (Mo), vanadium (V), iron (Fe). In some embodiments, the channel layer 180 may be formed of the same material as the material forming the current limiting layer 135.

The channel layer 180 protects the components disposed below the channel layer 180 from etching during etching of the light emitting structure 120 to be described later, and stably supports the light emitting device to protect them from damage that may occur in the manufacturing process. There is.

The channel layer 180 is etched to form grooves. The groove may be formed by a dry etching process using a mask. In addition, the current limiting layer 135 may be formed in the formed groove. In this case, when the channel layer 180 is etched according to an embodiment, an uneven structure may be formed on the channel layer 180. The uneven structure is formed on the channel layer 180 while forming a groove using a mask. can do.

The current limiting layer 135 distributes the flow of current flowing to the light emitting structure 120 in the horizontal direction, thereby preventing malfunction of the light emitting device due to overcurrent, thereby increasing the stability and reliability of the light emitting device.

The current limiting layer 135 may be formed between the ohmic layer 130 or the reflective layer 140 and the light emitting structure 120. The current limiting layer 135 may be formed using a material having a lower electrical conductivity than the reflective layer 140, a material forming a Schottky contact with the second conductive semiconductor layer 126, or an electrically insulating material. have. For example, the current limiting layer 135 is formed of ZnO, SiO ₂ , SiON, It may include at least one of Si ₃ N ₄ , Al ₂ O _3, TiO ₂ , Ti, Al, Cr.

As shown in FIG. 2C, an uneven structure is formed on the current limiting layer 135 or the channel layer 180.

In this case, the current limiting layer 135 or the channel layer 180 may include an uneven structure formed on a surface adjacent to the ohmic layer or the reflective layer. At this time, the uneven structure may be formed periodically or aperiodic, the uneven shape is not limited. For example, the concave-convex shape includes all shapes of single or complex shapes such as square, hemisphere, triangle, and trapezoid.

The uneven structure may be formed using a wet etching process or a dry etching process, or may be formed using a wet etching process and a dry etching process.

The dry etching method may be plasma etching, sputter etching, ion etching, etc., and the wet etching process may be a PEC (Photo Chemical Wet-etching) process.

At this time, in the PEC process, by adjusting the amount of the etchant and the difference in etching speed due to the crystallinity of the material constituting the current limiting layer 135 or the channel layer 180, the shape of the irregularities of the fine size can be adjusted. After the mask is formed, the uneven shape may be periodically adjusted through etching.

According to an embodiment, the step from the floor to the valley of the uneven structure may be formed in various ranges of values, for example, may be formed in 0.01 ~ 0.5㎛.

The second electrode 155 may be formed on the uneven structure of the current limiting layer 135 or the channel layer 180. The second electrode 155 may include at least one of the reflective layer 140 and the ohmic layer 130.

The second electrode 155 may be formed in a layer or a plurality of patterns under the second conductive semiconductor layer 126 for ohmic contact, and may be ohmic contact with a reflective metal or ohmic contact using a conductive oxide. .

The second electrode 155 may be formed of the metal, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), and IGTO (IGTO). among indium gallium tin oxide (AZO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrOx, RuOx, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO It may include at least one, but is not limited to such materials.

In addition, the second electrode 155 may be made of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, and a selective combination thereof. In addition, the second electrode 155 may be formed as a single layer or multiple layers of a reflective electrode material having ohmic characteristics. When the second electrode 155 plays an ohmic role, the ohmic layer 130 may not be formed.

In addition, the second electrode 155 may include a bonding layer, wherein the bonding layer is a barrier metal or a bonding metal, for example, Ti, Au, Sn, Ni, Cr, Ga, In, Bi It may include at least one of, Cu, Ag or Ta.

The second electrode 155 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.

The reflective layer 140 is made of a metal layer including aluminum (Al), silver (Ag), nickel (Ni), platinum (Pt), rhodium (Rh), or an alloy containing Al, Ag, Pt, or Rh, It may be formed in multiple layers using the metal material and light transmitting conductive materials such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, and ATO. In addition, the reflective layer 140 may be laminated with IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni, or the like. In addition, when the reflective layer 140 is formed of a material in ohmic contact with the light emitting structure (eg, the second conductivity-type semiconductor layer 126), the ohmic layer 130 may not be separately formed, but is not limited thereto. The reflective layer 140 may effectively reflect the light generated by the active layer 124 to greatly improve the light extraction efficiency of the light emitting device.

The ohmic layer 130 is in ohmic contact with a lower surface of the light emitting structure (eg, the second conductivity-type semiconductor layer 126), and may be formed in a layer or a plurality of patterns. The ohmic layer 130 may be selectively formed of a light transmissive conductive layer and a metal, and may be stacked to a thickness of about 200 angstroms. The ohmic layer 130 may selectively use a light transmissive conductive layer and a metal. For example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), and indium aluminum zinc (AZO) oxide), IGZO (indium gallium zinc oxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (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, Zn, Pt, Au, can be formed including at least one of Hf, and is not limited to these materials. The ohmic layer 130 may be formed by sputtering or electron beam deposition.

3 is a view showing an embodiment in which the uneven structure is formed in the barrier layer, and the second electrode is formed in the uneven structure.

Referring to FIG. 3, the second electrodes 130 and 140 include a first region 101 in contact with the light emitting structure 120 and a second region 102 except for the first region 101.

Among these, the barrier layer 135 or 180 may be formed between the light emitting structure 120 and the second region 102. That is, the uneven structure of the barrier layer 135 or 180 may be formed on the second region 102 of the second electrodes 130 and 140.

In this case, the channel layer 180 or the current limiting layer 135, which is the barrier layer, may have an uneven structure on a surface adjacent to the second electrodes 130 and 140.

Second electrodes 130 and 140 may be formed under the uneven structure. For example, the ohmic layer 130 may be formed on at least a portion of the uneven structure, and the reflective layer 140 may be formed under the ohmic layer 130.

For example, the ohmic layer 130 may be formed up to d2 of the step d1 from the valley to the floor of the uneven structure, and the reflective layer 140 may be formed up to d3.

On the other hand, Figure 4 is a view showing another embodiment in which the uneven structure is formed in the barrier layer, the second electrode is formed in the uneven structure.

4 illustrates another embodiment in which a first electrode is formed in an uneven structure.

Referring to FIG. 4, the second electrodes 130 and 140 include a first region 101 in contact with the light emitting structure 120 and a second region 102 except for the first region 101.

Among these, the barrier layer 135 or 180 may be formed between the light emitting structure 120 and the second region 102. That is, the uneven structure of the barrier layer 135 or 180 may be formed on the second region 102 of the second electrodes 130 and 140.

In this case, the channel layer 180 or the current limiting layer 135, which is the barrier layer, may have an uneven structure on a surface adjacent to the second electrodes 130 and 140.

Second electrodes 130 and 140 may be formed under the uneven structure. For example, an uneven structure is formed under the channel layer 180 or the current limiting layer 135 that is the barrier layer, the ohmic layer 130 is filled in the entire uneven structure, and the reflective layer 140 is below the ohmic layer 130. ) May be formed.

For example, the ohmic layer 130 may be formed on all of the steps d1 from the valley to the floor of the uneven structure, and the reflective layer 140 may be formed under the ohmic layer 130.

3 and 4 have described the case in which the ohmic layer 130 and the reflective layer 140 are included in the second electrode, the second electrode may further include a bonding layer, but is not limited thereto.

In addition, according to the exemplary embodiment, an uneven structure may be formed on the channel layer 180 or the current limiting layer 135 which is the barrier layer, and the reflective layer 140 may be formed on the entire unevenness, but is not limited thereto.

In addition, according to the exemplary embodiment, the uneven structure may be formed only on the channel layer 180, and the uneven structure may not be formed on the current limiting layer 135.

In addition, when the uneven structure is formed only on the channel layer 180, when the groove is formed after etching the channel layer 180 of FIG. 2B, the uneven structure may be formed on the channel layer 180. At this time, the groove may be formed using a mask by a process such as dry etching, and the concave-convex structure may be formed on the channel layer 180.

Therefore, the barrier layer of the embodiment includes an uneven structure formed on a surface adjacent to the second electrode, and the second electrode is formed on the uneven structure, thereby improving the bonding force between the barrier layer and the second electrode, and thus, the barrier layer and the second electrode. By preventing mechanical damage (eg, peeling) of the light emitting device due to the weakening of the adhesion between the electrodes, and minimizing the mechanical damage of the light emitting device, there is an effect that can increase the stability and reliability of the light emitting device.

Referring to FIG. 2D, an ohmic layer is formed on a groove between the channel layer 180 or the current limiting layer 135 and an uneven structure on the channel layer 180 or the current limiting layer 135.

The ohmic layer 130 may selectively use a light transmissive conductive layer and a metal. For example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), and indium aluminum zinc (AZO) oxide), IGZO (indium gallium zinc oxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (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, Zn, Pt, Au, can be formed including at least one of Hf, and is not limited to these materials. The ohmic layer 1300 may be formed by sputtering or electron beam deposition.

As described above, the ohmic layer 130 may be formed to fill all the unevenness on the channel layer 180 or the current limiting layer 135. When the ohmic layer 130 is not completely filled, the ohmic layer 130 may reflect the remaining unevenness of the reflective layer ( 140) can be filled.

Referring to FIG. 2E, the reflective layer 140 is stacked on the channel layer 180, the current limiting layer 135, and the ohmic layer 130.

The reflective layer 140 can be formed to a thickness of about 2500 angstroms. The reflective layer 140 may be formed of, for example, a metal or an alloy including at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, or Hf. Alternatively, the metal or alloy may be formed in a multilayer using light transmitting conductive materials such as ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, and ATO, and specifically, IZO / Ni, AZO / Ag, and IZO. / Ag / Ni, AZO / Ag / Ni, Ag / Cu, Ag / Pd / Cu and the like can be laminated. 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.

As shown in FIG. 2F, the conductive layer 170 is formed on the reflective layer 140. The conductive layer 170 is selected from the group consisting of nickel (Ni-nickel), platinum (Pt), titanium (Ti), tungsten (W), vanadium (V), iron (Fe), and molybdenum (Mo). It can be made of materials or alloys in which they are optionally included.

In this case, the conductive layer 170 may be formed using a sputtering deposition method. When using the sputtering deposition method, when ionized atoms are accelerated by an electric field and collide with the source material of the conductive layer 170, the atoms of the source material are ejected and deposited. In addition, according to the embodiment, an electrochemical metal deposition method, a bonding method using a eutectic metal, or the like may be used.

The conductive layer 170 supports the light emitting structure 120 as a whole, thereby minimizing mechanical damage (breaking or peeling, etc.) that may occur in the manufacturing process of the light emitting device, and also supports the substrate 160 or the bonding. The metal material forming the layer 150 may be prevented from diffusing into the light emitting structure 120.

In addition, according to an embodiment, the conductive layer 170 may include at least one protrusion toward the light emitting structure to improve the bonding strength of the light emitting device.

As shown in FIG. 2G, the bonding layer 150 may be formed to couple the support substrate 160 to the conductive layer 170. The bonding layer 150 is, for example, from the group consisting of gold (Au), tin (Sn), indium (In), silver (Ag), nickel (Ni), niobium (Nb) and copper (Cu). It may be formed of the material selected or alloys thereof.

And as shown in FIG. 2H. The support substrate 160 may be formed on the bonding layer 150.

The support substrate 160 may be made of a material selected from the group consisting of molybdenum (Mo), silicon (Si), tungsten (W), copper (Cu), and aluminum (Al) or alloys thereof. For example, gold (Au), copper alloy (Cu Alloy), nickel (Ni-nickel), 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. The conductive support substrate 160 may be formed using an electrochemical metal deposition method or a bonding method using a eutectic metal.

In some embodiments, when holes are injected into the second conductive semiconductor layer 126 through the conductive layer 170, the support substrate 160 may be made of an insulating material. It may be made of nitride. For example, the support substrate 160 may include a silicon oxide (SiO ₂ ) layer, an oxynitride layer, and an aluminum oxide layer.

As shown in FIG. 2I, the substrate 100 is separated.

The substrate 100 may be removed by a laser lift off (LLO) method using an excimer laser or the like, or may be a dry or wet etching method.

For example, when the laser lift-off method focuses and irradiates excimer laser light having a predetermined wavelength toward the substrate 100, thermal 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, separation of the substrate 100 occurs at a portion where the laser light passes.

As shown in FIG. 2J, the side surface of the light emitting structure 120 is etched. In this case, when a material forming the channel layer 180 is detected by an endpoint detecting method, a portion of the side surface of the light emitting structure 120 may be etched by stopping the etching.

At this time, the etching position may be adjusted so that the channel layer 180 is positioned under the light emitting structure 120 to be etched.

When the light emitting structure 120 is etched, the channel layer 180 protects the components disposed under the channel layer 180 from etching, and stably supports the light emitting device to protect against damages that may occur in the manufacturing process. .

In addition, an uneven structure is formed on the first conductive semiconductor layer 122 to improve light extraction efficiency.

The uneven structure changes the angle of incidence of the light emitted from the active layer 124 to enter the first conductivity type semiconductor layer 122, thereby reducing the total reflection on the surface of the first conductivity type semiconductor layer 122, thereby increasing the light extraction effect. It is possible to reduce the absorption of light emitted from the active layer 124 in the light emitting structure, thereby increasing the luminous efficiency.

The uneven structure may be formed periodically or aperiodically, and the uneven shape is not limited. For example, the concave-convex shape includes all shapes of single or complex shapes such as square, hemisphere, triangle, and trapezoid.

The uneven structure may be formed using a wet etching process or a dry etching process, or may be formed using a wet etching process and a dry etching process.

The dry etching method may be plasma etching, sputter etching, ion etching, etc., and the wet etching process may be a PEC (Photo Chemical Wet-etching) process.

At this time, in the case of the PEC process, by adjusting the amount of the etching liquid (eg, KOH) and the etching rate difference by the GaN crystallinity, it is possible to control the shape of the irregularities of the fine size. After the mask is formed, the uneven shape may be periodically adjusted through etching.

2K, the first electrode 190 may be formed on the first conductivity-type semiconductor layer 122. In this case, the first electrode 190 may be disposed on the light emitting structure 120. It may be formed to partially overlap the barrier layer 135 or 180 vertically.

The first electrode 190 may include molybdenum, chromium (Cr), nickel (Ni), gold (Au), aluminum (Al), titanium (Ti), platinum (Pt), vanadium (V), tungsten (W), It is made of any one metal selected from lead (Pd), copper (Cu), rhodium (Rh) and iridium (Ir) or an alloy of the metals.

In some embodiments, a passivation layer may be deposited on at least a portion of the channel layer 180, the light emitting structure 120, and the first electrode 190. Here, the passivation layer may be made of an insulating material, and the insulating material may be made of an oxide or nitride which is non-conductive. As an example, the passivation layer may be formed of a silicon oxide (SiO ₂ ) layer, an oxynitride layer, or an aluminum oxide layer.

5 is a cross-sectional view of an embodiment of a light emitting device package.

As shown, the light emitting device package according to the above-described embodiments, the package body 520, the first electrode layer 511 and the second electrode layer 512 installed on the package body 520, and the package body ( The light emitting device 500 and the resin layer 540 surrounding the light emitting device 500 according to the embodiment installed in the 520 and electrically connected to the first electrode layer 511 and the second electrode layer 512. Include.

The package body 520 may include a silicon material, a synthetic resin material, or a metal material. An inclined surface may be formed around the light emitting device 500 to increase light extraction efficiency.

The first electrode layer 511 and the second electrode layer 512 are electrically separated from each other, and provide power to the light emitting device 500. In addition, the first electrode layer 511 and the second electrode layer 512 may increase the light efficiency by reflecting the light generated from the light emitting device 500, the outside of the heat generated from the light emitting device 500 May also act as a drain.

The light emitting device 500 may be installed on the package body 520 or on the first electrode layer 511 or the second electrode layer 512.

The light emitting device 500 may be electrically connected to the first electrode layer 511 and the second electrode layer 512 by any one of a wire method, a flip chip method, and a die bonding method.

The resin layer 540 may surround and protect the light emitting device 500. In addition, the resin layer 540 may include a phosphor to change the wavelength of light emitted from the light emitting device 500.

The light emitting device package may mount at least one of the light emitting devices of the above-described embodiments as one or more, but 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. The light emitting device package, the substrate, and the optical member may 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, for example, the lighting system may include a lamp and a street lamp. .

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

100: substrate
120: light emitting structure 122: first conductive semiconductor layer
124: active layer 126: second conductive semiconductor layer
130: ohmic layer 135: current limiting layer
140: reflective layer 150: bonding layer
155: second electrode 160: support substrate
170: conductive layer 180: channel layer
190: first electrode
500 light emitting element 511 first electrode layer
512: second electrode layer 520: package body
540: resin layer

Claims (11)

A light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer;
A second electrode formed under the light emitting structure and including a first region in contact with the light emitting structure and a second region except for the first region; And
A barrier layer formed between the light emitting structure and the second region,
The barrier layer includes a concave-convex structure on a surface adjacent to the second electrode. The method of claim 1,
Steps from the valley to the floor of the uneven structure is formed of 0.01 ~ 0.5㎛. The method of claim 1,
The uneven structure is formed on the second region. The method of claim 1,
The second electrode includes at least one of an ohmic layer, a reflective layer, and a bonding layer. The method of claim 4, wherein
The ohmic layer is formed on at least part of the uneven structure, and the reflective layer is formed on the rest of the uneven structure. The method of claim 1,
The barrier layer includes at least one of a channel layer and a current limiting layer. The method of claim 6,
The channel layer includes the concave-convex structure on a surface adjacent to the second electrode, and the current limiting layer does not include the concave-convex structure on the surface adjacent to the second electrode. The method of claim 1,
And at least one first electrode formed on the light emitting structure so as to partially overlap the barrier layer. The method of claim 1,
The light emitting device further comprises a conductive layer formed under the second electrode. 10. The method of claim 9,
The conductive layer includes at least one protrusion toward the light emitting structure. The method of claim 10,
The second electrode surrounds the at least one protrusion included in the conductive layer.

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