KR102501191B1 - light emitting device - Google Patents

Abstract

The embodiment relates to a light emitting device having improved reliability by preventing separation of an electrode pad and a finger, comprising: a substrate; a light emitting structure disposed on the substrate and including a first semiconductor layer, an active layer, and a second semiconductor layer; a first electrode electrically connected to the first semiconductor layer exposed by removing the second semiconductor layer and the active layer; and a second electrode electrically connected to the second semiconductor layer and including an electrode pad and a finger, wherein the finger extends from the electrode pad so that the width gradually narrows as the distance from the electrode pad increases. and a second area extending from the first area and having a constant width.

Description

Light emitting device {light emitting device}

An embodiment of the present invention relates to a light emitting device having improved reliability.

A light emitting diode (LED) is one of light emitting devices that emits light when a current is applied thereto. A light emitting diode can emit light with high efficiency at a low voltage, and thus has an excellent energy saving effect. Recently, the luminance problem of light emitting diodes has been greatly improved, and they are applied to various devices such as backlight units of liquid crystal display devices, electronic signboards, displays, and home appliances.

A light emitting diode includes a light emitting structure including an N type semiconductor layer, an active layer, and a P type semiconductor layer provided on a substrate, and includes an N type electrode and a P type electrode connected to the light emitting structure. The light emitting diode as described above may emit light through a lens.

In general, in a light emitting device, a light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer is disposed on a substrate, and first and second electrodes are electrically connected to the first semiconductor layer and the second semiconductor layer, respectively. do. Also, the first and second electrodes may be connected to a lead frame or the like using a wire.

In this case, for easy injection of carriers into the semiconductor layer, the first and second electrodes may include electrode pads and fingers extending from the electrode pads. However, since the width of the finger is generally very narrow, the electrode pad and the finger may be separated when bonding the electrode and the wire.

1A and 1B are photographs of a finger being separated from a pad.

As shown in FIGS. 1A and 1B , when a wire is bonded to an electrode, a portion where a finger extends from an electrode pad may be separated. Accordingly, the electrode pad may be separated from the light emitting structure, resulting in a defect in the light emitting device, thereby reducing reliability.

Embodiments of the present invention provide a light emitting device having improved reliability by preventing separation between a pad and a finger and preventing separation of a pad.

The light emitting device of the embodiment includes a substrate; a light emitting structure disposed on the substrate and including a first semiconductor layer, an active layer, and a second semiconductor layer; a first electrode electrically connected to the first semiconductor layer exposed by removing the second semiconductor layer and the active layer; and a second electrode electrically connected to the second semiconductor layer and including an electrode pad and a finger, wherein the finger extends from the electrode pad so that the width gradually narrows as the distance from the electrode pad increases. and a second area extending from the first area and having a constant width.

The light emitting device of the present invention has the following effects.

First, the electrode includes an electrode pad and a finger extending from the electrode pad, and includes a region having a width that gradually narrows as the finger moves away from a portion adjacent to the electrode pad, preventing separation of the finger and the electrode pad.

Second, the second electrode is in direct contact with the second semiconductor layer through the hole exposing the second semiconductor layer by selectively removing the current blocking layer and the transparent electrode layer, thereby improving the contact characteristics between the second semiconductor layer and the second electrode. . Accordingly, peeling of the second electrode can be prevented.

1A and 1B are photographs of a finger being separated from a pad.
2A is a plan view of a light emitting device according to an embodiment of the present invention.
FIG. 2B is a cross-sectional view taken along line I-I' of FIG. 2A.
FIG. 2C is a cross-sectional view taken along line II-II' of FIG. 2A.
Figure 3a is the structure of the first electrode of Figure 2b.
Figure 3b is the structure of the second electrode of Figure 2b.
4 is a diagram comparing a plan view of an electrode pad of a general light emitting device and an electrode pad of a light emitting device of the present invention.
5A to 5C are diagrams illustrating a contact area between a second electrode and a second semiconductor layer of a light emitting device according to an embodiment of the present invention.
6A to 6C are plan views of a light emitting device according to another embodiment of the present invention.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers, such as first and second, may be used to describe various components, but the components are not limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a second element may be termed a first element, and similarly, a first element may be termed a second element, without departing from the scope of the present invention. The terms and/or include any combination of a plurality of related recited items or any of a plurality of related recited items.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, the embodiment will be described in detail with reference to the accompanying drawings, but the same or corresponding components regardless of reference numerals are given the same reference numerals, and overlapping descriptions thereof will be omitted.

Hereinafter, the light emitting device of the present invention will be described in detail with reference to the accompanying drawings.

2A is a plan view of a light emitting device according to an exemplary embodiment of the present invention, FIG. 2B is a cross-sectional view taken along line II-I' of FIG. 2A, and FIG. 2C is a cross-sectional view taken along line II-II' of FIG. 2A. And, Figure 3a is the structure of the first electrode of Figure 2b, Figure 3b is the structure of the second electrode of Figure 2b

2a, 2b and 2c, the light emitting device of the embodiment of the present invention is disposed on a substrate 100, and includes a first semiconductor layer 110a, an active layer 110b, and a second semiconductor layer 110c. The first electrode 120 and the second semiconductor layer 110c electrically connected to the first semiconductor layer 110a exposed by removing the light emitting structure 110, the second semiconductor layer 110c and the active layer 110b, and It is electrically connected and includes a second electrode 130 including an electrode pad 230a and a finger 230b, and the finger 230b has an electrode pad ( 230a) includes a first region (a) extending from the first region (a) and a second region (b) extending from the first region (a) and having a constant width.

Specifically, the substrate 100 may be formed of a material selected from sapphire (Al ₂ O ₃ ), SiC, GaAs, GaN, ZnO, Si, GaP, InP, and Ge, but is not limited thereto. Although not shown, a concavo-convex pattern (not shown) may be formed on the surface of the substrate 100 to disperse light emitted from the light emitting structure 110 to improve light emitting characteristics. The concavo-convex pattern (not shown) may be a regular or irregular pattern.

Although not shown, a buffer layer (not shown) may be further formed between the substrate 100 and the light emitting structure 110 . The buffer layer (not shown) is for increasing the stability of the light emitting device by reducing the difference in lattice constant and thermal expansion coefficient between the substrate 100 and the first semiconductor layer 110a. The buffer layer (not shown) may be formed by growing an undoped nitride semiconductor, and when the first semiconductor layer 110a is grown on a buffer layer (not shown) made of an undoped nitride semiconductor, the first semiconductor layer 110a ) can improve the crystal quality of At this time, the material of the buffer layer (not shown) is not limited thereto.

The first semiconductor layer 110a may be implemented with a compound semiconductor of group 3-5, group 2-6, or the like, and may be doped with a first conductivity type dopant. For example, the first semiconductor layer 110a may be a semiconductor having a composition formula of InxAlyGa1-x-yN (0≤x≤1, 0≤y≤1, 0≤x+y≤1), Si, Ge An n-type dopant such as , Sn, or the like may be doped.

The active layer 110b generates light by energy generated during recombination of electrons and holes, which are carriers provided from the first semiconductor layer 110a and the second semiconductor layer 110c. can The active layer 110b may be a semiconductor compound, for example, a compound semiconductor of Group 3-5 or Group 2-6, and may have a single well structure, a multi-well structure, a quantum-wire structure, or a quantum dot. (Quantum Dot) structure, etc.

When the active layer 110b has a quantum well structure, a well layer having a composition formula of InxAlyGa1-x-yN (0≤x≤1, 0≤y≤1, 0≤x+y≤1) and InaAlbGa1-a-bN ( 0≤a≤1, 0≤b≤1, 0≤a+b≤1) may have a single or quantum well structure having a barrier layer. The well layer may be a material having a lower band gap than the energy band gap of the barrier layer.

The second semiconductor layer 110c may be implemented with a compound semiconductor of group 3-5, group 2-6, or the like, and may be doped with a second conductivity type dopant. For example, the second semiconductor layer 110c may be a semiconductor having a composition formula of InxAlyGa1-x-yN (0≤x≤1, 0≤y≤1, 0≤x+y≤1), Mg, Zn , Ca, Sr, Ba, etc. may be doped with a p-type dopant.

The light emitting structure 110 as described above may be formed of at least one of np, pn, npn, and pnp junction structures, and the light emitting structure 110 according to an embodiment of the present invention includes an n-type semiconductor layer and a p-type semiconductor layer. It may be a variety of structures including. In addition, doping concentrations of impurities in the first semiconductor layer 110a and the second semiconductor layer 110c may be uniform or non-uniform. That is, the doping structure of the light emitting structure 110 may be formed in various ways, but is not limited thereto.

A portion of the second semiconductor layer 110c and the active layer 110b is removed by a mesa etching process, and the first semiconductor layer (110b) is removed from the removed area. 110a) may be exposed. And, the first electrode 120 may be disposed on the exposed first semiconductor layer 110a.

The first electrode 120 is electrically connected to the first semiconductor layer 110a on the first semiconductor layer 110a. At this time, the first electrode 120 may be formed of a single layer or a multilayer structure as shown in FIG. 3A.

For example, the first electrode 120 may include sequentially stacked first layers 120a to fourth layers 120d. The lowermost first layer 120a is in contact with the first semiconductor layer 110a and may be made of Cr, Ti, or the like for ohmic contact between the first electrode 120 and the first semiconductor layer 110a. Also, the second layer 120b may be a reflective layer. The second layer 120b may be made of a metal having high reflectivity, or may be formed of Al, Ag, Ru, Pd, Rh, Pt, Ir, or an alloy of the above metal.

The third layer 120c is formed of Au, Cu, Hf, Ni, Mo, V, W, Rh, Ru, Pt, Pd, La, Ta, Ti, and alloys thereof, and is the material of the second layer 120b, which is a reflective layer. It can function as an anti-diffusion layer preventing this diffusion. If the thickness of the third layer 120c is too thin, diffusion of the material of the second layer 120b cannot be prevented, and if the thickness is too thick, the third layer 120c, the second layer 120b and the fourth The third layer 120c may be peeled off due to stress between the layers 120d. Accordingly, the third layer 120c preferably has a thickness of 250 nm to 500 nm. And, the fourth layer 120d is connected to the wire and may be formed of a metal such as Au or Ag. The structure of the first electrode 120 is not limited thereto and can be changed.

The second electrode 130 may be disposed on the second semiconductor layer 110c and electrically connected to the second semiconductor layer 110c. In this case, a transparent electrode layer 140 may be further disposed between the second electrode 130 and the second semiconductor layer 110c. The transparent electrode layer 140 may include indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), aluminum gallium zinc oxide (AGZO), indium zinc tin oxide (IZTO), and indium aluminum zinc oxide (IAZO). , Indium Gallium Zinc Oxide (IGZO), Indium Gallium Tin Oxide (IGTO), Antimony Tin Oxide (ATO), Gallium Zinc Oxide (GZO), IZO Nitride (IZON), ZnO, IrOx, RuOx, and NiO. can be chosen

The second electrode 130 may overlap the current blocking layer (CBL) 150 with the transparent electrode layer 140 therebetween. The current blocking layer 150 is to prevent carriers from being transferred only to the second semiconductor layer 110c in an area overlapping the second electrode 130 . Carriers injected from the second electrode 130 may be evenly injected into the second semiconductor layer 110c by the current blocking layer 150 .

The current blocking layer 150 may be made of a metal capable of forming a Schottky contact with the second semiconductor layer 110c. For example, the current blocking layer 150 may be formed of at least one of titanium (Ti), zirconium (Zr), chromium (Cr), gold (Au), and tungsten (W), or an alloy including at least one of them. there is. In addition, the current blocking layer 150 may be formed of a dielectric such as SiOx, SiON, or SixNy, but is not limited thereto.

Although the drawing shows that the second electrode 130 is a single layer, as shown in FIG. 3B, the second electrode 130 may also have a multilayer structure. The second electrode 130 may have a structure in which a first layer 130a to a fourth layer 130d are sequentially stacked, and the first layer 130a may contact the transparent electrode layer 140 .

Referring back to FIGS. 2A, 2B, and 2C , holes, which are carriers injected through the second electrode 130, are larger than electrons, which are carriers, which are injected through the first electrode 120. Movement speed is very slow. Accordingly, the second electrode 130 may further include a finger 230b. The finger 230b may have a structure extending from the electrode pad 230a.

However, when the width of the finger 230b is too wide, light transmittance may decrease. Therefore, in general, the width w of the finger 230b is much smaller than the diameter r1 of the electrode pad 230a.

For example, when the diameter r1 of the electrode pad 230a is large or the width of the finger 230b is wide, the contact area between the first electrode 130 and the first semiconductor layer 110a increases, so that the driving voltage However, when the diameter r1 of the electrode pad 230a is too large or the width of the finger 230b is too wide, among the light emitted from the active layer 110b, the opaque electrode pad 230 and the finger 230b As the amount of light absorbed in increases, the light output decreases. Conversely, when the diameter r1 of the electrode pad 230a is too small or the width of the finger 230b is too narrow, the driving voltage increases.

Accordingly, the diameter r1 of the electrode pad 230a may be 50 μm to 150 μm, and the width w of the finger 230b may be 3 μm to 7 μm. At this time, the diameter r1 of the electrode pad 230a and the width w of the finger 230b are not limited thereto.

However, since the width w of the finger 230b is narrow, when a wire is bonded to the second electrode 130, a portion where the finger 230b extends from the electrode pad 230a may be separated. And, accordingly, the electrode pad 230a may be peeled from the light emitting structure. In addition, since carriers are not transmitted to the finger 230b, it is difficult to uniformly emit light in the entire area of the active layer 110b, and thus light emitting efficiency may decrease.

4 is a diagram comparing a plan view of an electrode pad of a general light emitting device and an electrode pad of a light emitting device of the present invention.

As shown in FIG. 4 , the width of the finger 23b of the second electrode 13 of the general light emitting element a is constant. That is, the width of the finger 23b is the same in the area adjacent to the electrode pad 23a or at the end relatively far from the electrode pad 23a.

On the other hand, in the second electrode 130 of the light emitting element (b) of the embodiment of the present invention, the width of the finger 230b at the portion where the electrode pad 230a and the finger 230b are connected is from the electrode pad 230a to the finger ( 230b) is formed in a form in which the width (w) gradually becomes narrower toward the end. Specifically, the finger 230b extends from the first region a extending from the electrode pad 230a and the first region a so that the width w gradually narrows as the distance from the electrode pad 230a increases, and the width (w) includes a constant second region (b).

Therefore, in the light emitting device of the embodiment of the present invention, the second electrode 130 of the light emitting device of the present invention has the same length as the second electrode 130 by the second region (b) of the finger 230b, and the electrode pad 230a The area of is larger than that of the general second electrode (13 in FIG. 4(a)) having the same diameter. Specifically, the area X2 of the second electrode 130 of the length L including the electrode pad 230a and the second region b of the finger 230b is equal to the length L of the second electrode ( 13) is wider than the area (X1).

However, as the area of the second electrode 130 increases, light transmittance decreases due to the opaque second electrode 130 . Therefore, it is preferable that the relatively narrow second region (b) of the finger 230b is longer than the length of the first region (a).

In addition, the area X2 of the second region b of the electrode pad 230a and the finger 230b according to the embodiment of the present invention may satisfy Equation 1 below. In this case, light loss due to the second electrode 130 is minimized and at the same time, separation between the electrode pad 230a and the finger 230b can be prevented.

In particular, in the light emitting device according to the embodiment of the present invention, the second electrode 130 is electrically connected to the second semiconductor layer 110c through the transparent electrode layer 140 . However, in this case, contact characteristics between the second electrode 130 and the transparent electrode layer 140 are not as good as those between the first semiconductor layer 110a and the first electrode 120 .

That is, even if the first layer 120a of the first electrode 120 and the first layer 130a of the second electrode 130 include the same material, the first layers 120a and 130a are more dense than the transparent electrode layer 140. Contact characteristics are superior to those of the GaN first semiconductor layer 110a.

Therefore, in the light emitting device according to another embodiment of the present invention, the upper surface of the second semiconductor layer 110c is exposed by partially removing the transparent electrode layer 140 and the current blocking layer 150 . Also, since the second electrode 130 is disposed to directly contact the exposed upper surface of the second semiconductor layer 110c, contact characteristics of the second electrode 130 may be improved. In particular, it is preferable that the region directly contacting the second semiconductor layer 110c is the electrode pad 230a, and the finger 230b may overlap the current blocking layer 150 and the transparent electrode layer 140.

5A to 5C are diagrams illustrating a contact area between a second electrode and a second semiconductor layer of a light emitting device according to an embodiment of the present invention.

5A to 5C, the current blocking layer 150 and the transparent electrode layer 140 are partially removed to expose the second semiconductor layer 110c, so that the current blocking layer 150 and the transparent electrode layer 140 are A hole 140a exposing the second semiconductor layer 110c may be included. Also, the second electrode 130 may directly contact the exposed second semiconductor layer 110c. In the drawing, it is shown that the upper surface of the hole 140a is circular. For example, as illustrated, when the upper surface of the hole 140a is circular, the electrode pad 230a may also be formed in a circular shape.

Therefore, it is preferable that the region in direct contact with the second semiconductor layer 110c is the electrode pad 230a of the second electrode 130, and the finger 230b is provided with the current blocking layer 150 and the transparent electrode layer 140. may overlap.

In addition, an insulating layer 160 may be further disposed to surround the transparent electrode layer 150 . The insulating layer 160 may be made of an insulating material such as SiO 2 , MgO, or SiN, and may extend to the upper surface of the substrate 100 .

A portion of the current blocking layer 150 is removed to expose the second semiconductor layer 110c, and the transparent electrode layer 140 disposed on the current blocking layer 150 also exposes the second semiconductor layer 110c. Some may be removed. Also, the electrode pad 230a of the second electrode 130 may directly contact the second semiconductor layer 110c exposed by the current blocking layer 150 and the transparent electrode layer 140 .

Specifically, as shown in FIGS. 5A and 5B , an edge of the electrode pad 230a may be disposed to extend to an upper surface of the transparent electrode layer 140 surrounding the hole 140a.

In particular, in the region removed to expose the second semiconductor layer 110c, the side surface of the current blocking layer 150 and the edge of the transparent electrode layer 140 may be different from each other as shown in FIG. 5A. In this case, since the edge of the transparent electrode layer 140 completely covers the edge of the current blocking layer 150, only the transparent electrode layer 140 is exposed on the inner surface of the hole 140a.

The first interval d1 of the transparent electrode layer 140 extending to the edge of the current blocking layer 150 is preferably 4 μm or more in consideration of a process margin. In addition, the second interval d2 where the upper surface of the transparent electrode layer 140 and the electrode pad 230a overlap in the area surrounding the hole 140a increases the process margin of the transparent electrode layer 140a and the second electrode 130. Considering that, it is preferable that it is 8 μm or more.

Also, the diameter r2 of the hole 140a is preferably 25 μm or more in consideration of the bonding area between the second semiconductor layer 110c and the electrode pad 230a. Accordingly, the diameter r2 of the hole 140a may satisfy Equation 2 below. At this time, r1 is the diameter of the electrode pad 230a of the second electrode 130.

Also, the second interval d2 where the upper surface of the transparent electrode layer 140 and the electrode pad 230a overlap each other satisfies Equation 3 below.

For example, when the diameter r1 of the electrode pad 230a is 70 μm, the diameter r2 of the hole may be 46 μm.

And, as shown in FIG. 5B, the side surface of the current blocking layer 150 and the edge of the transparent electrode layer 140 may coincide with each other in the area surrounding the hole 150a. In this case, the side surface of the hole 140a may coincide with the transparent electrode layer. 140 and the current blocking layer 150 may both be exposed. Also, as shown in FIG. 5C , an edge of the electrode pad 230a may partially overlap the transparent electrode layer 140 in an area surrounding the hole 150a. At this time, the degree of overlap between the edge of the electrode pad 230a and the transparent electrode layer 140 can be easily changed.

Hereinafter, a light emitting device according to another embodiment of the present invention will be described in detail.

6A to 6C are plan views of a light emitting device according to another embodiment of the present invention.

As shown in FIG. 6A , the second electrode 130 may include two fingers 230b. In this case, the two fingers 230b may symmetrically extend to face each other on one electrode pad 230a so as to facilitate carrier diffusion. Accordingly, the two fingers 230b may maintain a uniform distance from the front surface of the light emitting device, and thus, current may flow uniformly.

Also, as shown in FIG. 6B , the first electrode 120 may also include an electrode pad 220a and a finger 220b extending from the electrode pad 220a. In this case, the finger 220b of the first electrode 120 also has a first region (not shown) whose width gradually decreases as it moves away from the adjacent portion of the electrode pad 220a and a second region (not shown) having a constant width. It can be made including.

In addition, as shown in FIG. 6C, the finger 230b extends from the first area a extending from the electrode pad 230a and the first area a so that the width gradually narrows as the finger 230b moves away from the electrode pad 230a. It may include a second area (b) having a constant width and a third area (c) extending from the second area (b) and having a gradually narrower width as the distance from the second area (b) increases. At this time, the length of the third region (c) is preferably shorter than the length of the first region (a).

In the light emitting device of the present invention as described above, the second electrode 130 includes an electrode pad 230a and one or more fingers 230b extending from the electrode pad 230a, and the finger 230b extends from the electrode pad 230a A region (a) having a width gradually narrowing as one moves away from an adjacent portion is included, so that separation of the finger 230b and the electrode pad 230a can be prevented. In addition, the second electrode 130 selectively removes the current blocking layer 150 and the transparent electrode layer 140 to expose the second semiconductor layer 110c through the hole 140a. Contact characteristics between the second semiconductor layer 110c and the second electrode 130 are improved by direct contact.

The light emitting device according to the embodiment of the present invention as described above may function as a backlight unit of a display device. In this case, the display device may include a bottom cover, a reflector, a light emitting module, a light guide plate, an optical sheet, a display panel, an image signal output circuit, and a color filter. The bottom cover, the reflector, the light emitting module, the light guide plate, and the optical sheet may form a backlight unit.

A reflector is disposed on the bottom cover, and the light emitting module emits light. The light guide plate is disposed in front of the reflector to guide light emitted from the light emitting module forward, and the optical sheet includes a prism sheet and is disposed in front of the light guide plate. A display panel is disposed in front of the optical sheet, an image signal output circuit supplies image signals to the display panel, and a color filter is disposed in front of the display panel.

In addition, the light emitting device may be applied to a lighting device such as a lamp, a head lamp, or a street lamp.

The embodiments of the present invention described above are not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible within a range that does not deviate from the technical spirit of the embodiments. It will be clear to those skilled in the art.

100: substrate 110: light emitting structure
110a: first semiconductor layer 110b: active layer
110c: second semiconductor layer 120: first electrode
120a, 130a: first layer 120b, 130b: second layer
120c, 130c: 3rd layer 120d, 130d: 4th layer
130: second electrode 140: transparent electrode layer
140a: hole 150: current blocking layer
160: insulating layer 220a, 230a: electrode pad
220b, 230b: Finger

Claims (14)

Board;
a light emitting structure disposed on the substrate and including a first semiconductor layer, an active layer, and a second semiconductor layer;
a first electrode electrically connected to the first semiconductor layer exposed by removing the second semiconductor layer and the active layer; and
A second electrode electrically connected to the second semiconductor layer and including an electrode pad and a finger,
The finger includes a first region extending from the electrode pad and a second region extending from the first region and having a constant width so that the width gradually decreases as the distance from the electrode pad increases;
A current blocking layer and a transparent electrode layer sequentially stacked between the second electrode and the second semiconductor layer are disposed,
The electrode pad is in direct contact with the second semiconductor layer through a hole formed by selectively removing the current blocking layer and the transparent electrode layer to expose an upper surface of the second semiconductor layer,
The edge of the transparent electrode layer completely covers the edge of the current blocking layer, so that only the transparent electrode layer is exposed on the inner surface of the hole, or the edge of the current blocking layer and the edge of the transparent electrode layer coincide with each other. According to claim 1,
A length of the second region is longer than a length of the first region. According to claim 1,
The first electrode has a structure including the electrode pad and a finger,
Two or more of the fingers extend from one of the electrode pads,
The two fingers extend symmetrically to face each other on the one electrode pad. According to claim 1,
An edge of the electrode pad completely overlaps the upper surface of the transparent electrode layer so as to surround the hole, or an edge of the electrode pad partially overlaps the upper surface of the transparent electrode layer. delete delete delete delete delete delete delete delete delete delete

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