KR20160081787A - Highly efficient light-emitting diode - Google Patents

Abstract

The present invention relates to a highly efficient light emitting diode. The highly efficient light emitting diode comprises: a first conductive type semiconductor layer; a mesa including a second conductive type semiconductor layer arranged on the first conductive type semiconductor layer and an active layer arranged between the first conductive type semiconductor layer and the second conductive type semiconductor layer; and a first electrode arranged on the mesa. Additionally, the first conductive type semiconductor layer comprises: a first contact area arranged near the mesa, along the outline of the first conductive type semiconductor layer; and a second contact area which is partially covered by the mesa. Meanwhile, the first electrode is electrically connected to at least parts of the first contact area and at least parts of the second contact area. Here, the line width of the area where the first contact area is in contact with the first electrode may be wider than the line width of the area where the second contact area is in contact with the first electrode. The purpose of the present invention is to provide the light emitting diode whose forward voltage is low, thereby preventing damage to the light emitting diode, caused by cracks, and improving reliability and efficiency.

Description

[0001] The present invention relates to a high-efficiency light-emitting diode

The present invention relates to a high efficiency light emitting diode, and more particularly, to a light emitting diode capable of lowering a forward voltage by adjusting a region where a first electrode and a first conductivity type semiconductor layer are in contact with each other.

Light emitting diodes (LEDs) are solid state devices that convert electrical energy into light and generally comprise an active layer of one or more semiconductor materials interposed between semiconductor layers doped with opposite conductivity type impurities. When a bias is applied across these doping layers, electrons and holes are injected into the active layer and recombined to generate light.

A forward voltage Vf is supplied to the light emitting diode to generate light, and a light emitting diode having an excellent light emitting efficiency is generally a light emitting diode capable of emitting the same amount of light at a lower forward voltage. Therefore, methods for lowering the forward voltage of the light emitting diode have been attempted.

On the other hand, in the dicing process of separating the wafer type light emitting diodes into individual light emitting diodes, cracks are likely to be generated in the insulating layer exposed on the cut surface. Such a crack can proceed inside the light emitting diode. Furthermore, interface delamination may occur where the insulating layer is separated from the semiconductor layer due to the crack. Accordingly, contaminants such as moisture or the like may penetrate into the light emitting diode along the crack or the interface between the insulating layer and the semiconductor layer, and the light emitting diode may be contaminated, and the peeling force of the layers in the light emitting diode may decrease, There is a possibility that the reliability of the apparatus is deteriorated.

Therefore, it is necessary to prevent the occurrence of cracks in the insulating layer and to improve the reliability of the light emitting diode.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light emitting diode having a low forward voltage.

Another object of the present invention is to provide a light emitting diode which can prevent damage to a light emitting diode due to cracks, thereby improving reliability and luminous efficiency.

According to an embodiment of the present invention, there is provided a light emitting diode including: a first conductive semiconductor layer; A second conductivity type semiconductor layer disposed on the first conductivity type semiconductor layer, and an active layer disposed between the second conductivity type semiconductor layer and the first conductivity type semiconductor layer; And a first electrode disposed on the mesa, wherein the first conductive type semiconductor layer comprises: a first contact region disposed around the mesa along an outline of the first conductive type semiconductor layer; And a second contact region at least partially surrounded by the mesa, wherein the first electrode is electrically connected to at least a portion of the first contact region and to at least a portion of the second contact region, And the line width of the area in which the first electrode is in contact may be larger than the line width of the area in which the second contact area is in contact with the first electrode. The area where the first electrode and the first conductivity type semiconductor layer are in contact with each other through the first contact region is increased relatively to the area of the first electrode and the first conductivity type semiconductor layer in contact with each other through the second contact region, The forward voltage Vf can be reduced. Further, the current can be more effectively dispersed in the horizontal direction, and the luminous efficiency can be improved.

The second contact area may be connected to the first contact area. Thereby, the current can be more effectively dispersed in the horizontal direction, and the luminous efficiency can be improved.

The length of the second contact region in the major axis direction may be 0.5 times or more the length of one side of the light emitting diode. In this case, since the region in which the first electrode and the first conductivity type semiconductor layer are in contact can be increased, the current flowing from the first electrode to the first conductivity type semiconductor layer can be more effectively dispersed, .

The line width of the region in which the first contact region and the first electrode are in contact may exceed 10 mu m and the line width of the region in which the second contact region and the first electrode are in contact may be 10 mu m or less.

And a first insulating layer disposed between the first electrode and the mesa, wherein the first insulating layer may partially expose the first contact region and the second contact region.

The first insulating layer may be disposed adjacent to the mesa, rather than a region in contact with the first contact region and the first electrode. Accordingly, the area of contact between the first electrode and the first conductivity type semiconductor layer can be increased without reducing the light emitting area. In addition, in the dicing process for separating the wafer-type light emitting diodes into the individual light emitting diodes, it is possible to prevent cracks from being generated in the first insulating layer disposed outside the first conductivity type semiconductor layer. Therefore, the peeling force of the first electrode or the second insulating layer, which will be described later, can be prevented from being weakened due to penetration of contaminants such as moisture through cracks, and the first electrode can be prevented from being contaminated, Reliability can be enhanced.

The first electrode may contact the first contact region and the second contact region exposed by the first insulating layer, and may expose an outer portion of the first contact region.

The thickness of a portion of the first conductive semiconductor layer that is not disposed below the first insulating layer may be smaller than a thickness of a portion disposed below the first insulating layer. A part of the upper surface of the first conductive type semiconductor layer is etched and removed, so that inert particles or the like, which deteriorates conductivity and adhesion, can be removed.

The thickness of the first insulating layer disposed on the upper surface of the second conductive type semiconductor layer may be equal to the thickness of the first insulating layer disposed on the upper surface of the first conductive type semiconductor layer. As a result, external contaminants can be prevented from penetrating into the mesa side surface.

And a second insulating layer covering the second contact region exposed by the first electrode and the first electrode.

Wherein the first electrode is a composite layer composed of a plurality of layers,

An area of the upper surface of the first electrode in contact with the second insulating layer may be a Ti layer. Accordingly, the adhesion between the first electrode and the second insulating layer is improved, and reliability can be improved.

The second insulating layer may include an opening for exposing the first electrode, and an area of the upper surface of the first electrode exposed by the opening of the second insulating layer may be an Au layer.

And a first pad in contact with the first electrode, wherein the first pad is in contact with the exposed Au layer. Accordingly, the adhesion between the first pad and the first electrode can be improved and the resistance can be reduced.

And a second electrode disposed on the second conductive type semiconductor layer and electrically connected to the second conductive type semiconductor layer, wherein the second electrode is insulated from the first electrode by the first insulating layer .

The thickness of the first insulating layer disposed on the upper surface of the second electrode may be smaller than the thickness of the first insulating layer disposed on the upper surface of the second conductive type semiconductor layer.

The second electrode may be a composite layer including a plurality of layers, and the upper surface of the second electrode may be a Ti layer in contact with the first insulating layer. Accordingly, the adhesion between the second electrode and the first insulating layer is improved, and reliability can be improved.

The first insulating layer includes an opening for exposing the second electrode, and an exposed region of the upper surface of the second electrode by the opening of the first insulating layer may be an Au layer.

And a second pad in contact with the second electrode, wherein the second pad is in contact with the exposed Au layer. Accordingly, the adhesion between the second pad and the second electrode can be improved and the resistance can be reduced.

And a growth substrate disposed under the first conductive type semiconductor layer.

The second insulating layer may cover a whole area of the side surface of the first conductivity type semiconductor layer and a part of a side surface of the growth substrate. As a result, the first conductivity type semiconductor layer can be protected from external moisture or impact, and the interface between the growth substrate and the first conductivity type semiconductor layer can be prevented from spreading, so that the reliability of the light emitting diode can be improved .

The growth substrate may include at least one modified region having a banding phenomenon extending horizontally on at least one side of the growth substrate. Accordingly, extraction efficiency of light generated in the active layer to the outside can be improved.

The second insulating layer may be spaced apart from the first conductive semiconductor layer by a predetermined distance. Thus, damage to the second insulating layer can be minimized in the step of separating into individual elements.

The mesa includes a plurality of protrusions protruding toward one side of the first conductive semiconductor layer; And a plurality of protrusions protruding toward the other side disposed opposite to the one side surface. As a result, not only in the region adjacent to one side of the first conductivity type semiconductor layer but also in the region adjacent to the other side, the current movement between the second electrode on the protrusion and the first electrode disposed on the second contact region is smooth . Therefore, the degree of light emission of the region adjacent to the other side can be improved.

According to embodiments of the present invention, the current flowing from the first electrode to the first conductivity type semiconductor layer can be effectively dispersed, so that the forward voltage can be reduced. In addition, since the first electrode can be prevented from being contaminated by cracks in the first insulating layer, the reliability of the light emitting diode can be enhanced.

1 is a plan view illustrating a light emitting diode according to an embodiment of the present invention.
2 is a cross-sectional view taken along the tear line AB-B'-A 'of FIG.
FIG. 3 is a cross-sectional view illustrating a light emitting diode according to an embodiment of the present invention taken along the perforated line C-C 'of FIG.
4 is an enlarged view of a portion I ₁ of FIG. 2;
5 is a cross-sectional view illustrating a light emitting diode and a circuit member on which the light emitting diode is mounted according to an embodiment of the present invention.
Figure 6 is an enlarged view of a portion (I ₂₎ of FIG.
FIG. 7 is an enlarged view of a portion I ₃ of FIG. 6; FIG.
8 is a cross-sectional view illustrating a light emitting diode according to an embodiment of the present invention mounted on a circuit member.
9 is a plan view illustrating a light emitting diode according to another embodiment of the present invention.
10 is a cross-sectional view taken along the tear line AB-B'-A 'in Fig.
11 is a side view of the light emitting diode of Fig.
12 is a plan view illustrating a light emitting diode according to another embodiment of the present invention.
13 is a cross-sectional view taken along the line AB-B'-A 'in FIG.
14 is a plan view illustrating a light emitting diode according to another embodiment of the present invention.
15 is a cross-sectional view taken along line A-A 'in Fig.
16 is a cross-sectional view taken along line B-B 'in Fig.
17 is an exploded perspective view illustrating an example in which a light emitting diode according to an embodiment of the present invention is applied to a lighting apparatus.
18 is a cross-sectional view for explaining an example in which a light emitting diode according to an embodiment of the present invention is applied to a display device.
19 is a cross-sectional view for explaining an example of applying a light emitting diode according to an embodiment of the present invention to a display device.
20 is a cross-sectional view illustrating an example in which a light emitting diode according to an embodiment of the present invention is applied to a headlamp.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so that those skilled in the art can sufficiently convey the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. It is also to be understood that when an element is referred to as being "above" or "above" another element, But also includes the case where there are other components in between. Like reference numerals designate like elements throughout the specification.

1 is a plan view for explaining a light emitting diode 200 according to an embodiment of the present invention, FIG. 2 is a sectional view taken along a perforated line AB-B'-A 'of FIG. 1, C-C ', and Fig. 4 is an enlarged view of a portion (I) of Fig.

1 to 4, a light emitting diode 200 according to an exemplary embodiment of the present invention includes a first conductive semiconductor layer 111, an active layer 112, and a second conductive semiconductor layer 113 And may include a mesa M, a first insulating layer 130, a first electrode 140, and a second insulating layer 150, and further includes a growth substrate 100 and a second electrode 120 can do.

The growth substrate 100 is not limited as long as it can grow the first conductivity type semiconductor layer 111, the active layer 112 and the second conductivity type semiconductor layer 113. For example, the growth substrate 100 may be a sapphire substrate, A carbide substrate, a gallium nitride substrate, an aluminum nitride substrate, a silicon substrate, or the like. In particular, in this embodiment, the growth substrate 100 may be a patterned sapphire substrate (PSS). The side surface of the growth substrate 100 may include an inclined surface, whereby the extraction of the light generated in the active layer 112 can be improved.

The second conductive semiconductor layer 113 may be disposed on the first conductive semiconductor layer 111. The active layer 112 may include a first conductive semiconductor layer 111 and a second conductive semiconductor layer 113, As shown in FIG. The first conductive semiconductor layer 111, the active layer 112, and the second conductive semiconductor layer 113 may include a III-V compound semiconductor, for example, (Al, Ga, In) N Based semiconductor, for example. The first conductivity type semiconductor layer 111 may include an n-type impurity (for example, Si), and the second conductivity type semiconductor layer 113 may include a p-type impurity (for example, Mg) have. It may also be the opposite. The active layer 112 may comprise a multiple quantum well structure (MQM). When a forward bias is applied to the light emitting diode 200, electrons and holes are combined with each other in the active layer 112 to emit light. The first conductivity type semiconductor layer 111, the active layer 112 and the second conductivity type semiconductor layer 113 are formed on the growth substrate 110 by using a technique such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE) 100). ≪ / RTI >

The light emitting diode 200 according to an exemplary embodiment of the present invention may include at least one mesa M including an active layer 112 and a second conductive semiconductor layer 113. Referring to FIG. 1, the mesa M may include a plurality of protrusions, and a plurality of protrusions may be spaced apart from each other. The present invention is not limited thereto, and the light emitting diode 200 may include a plurality of mesas M spaced from each other. The side surface of the mesa M may be inclined by using a technique such as photoresist reflow and the side surface of the inclined mesa M may improve the luminous efficiency generated in the active layer 112. [

The first conductivity type semiconductor layer 111 may include a first contact region R ₁ and a second contact region R ₂ exposed through the mesa M. [ Since the mesa M is formed by removing the active layer 112 and the second conductivity type semiconductor layer 113 disposed on the first conductivity type semiconductor layer 111, Type semiconductor layer 111 is exposed. The first electrode 140 to be described later may be electrically connected to the first conductivity type semiconductor layer 111 by being in contact with the first contact region R ₁ and the second contact region R ₂ . The first contact region R ₁ may be disposed around the mesa M along the outer periphery of the first conductivity type semiconductor layer 111 and specifically between the mesa M and the side of the light emitting diode 200 And may be disposed along the upper surface of the first conductivity type semiconductor layer. The second contact region R ₂ may be at least partially surrounded by the mesa M. [ For example, referring to FIGS. 1 and 2, the first contact region R ₁ may be disposed adjacent to the sides of the first conductive semiconductor layer 111, and the second contact region R ₂ may be disposed adjacent to the second contact region R ₁ . May be disposed between the protrusions of the mesa (M) and partially surrounded by the mesa (M). Although not shown, when the mesa is plural, the second contact region R ₂ may be disposed between the plurality of mesas. Further, the second contact region R ₁ may be completely surrounded by the mesa M. Accordingly, the current can be moved at the outer portion and the center portion of the light emitting diode 200, so that the current can be effectively dispersed.

The length of the second contact region R ₂ in the major axis direction may be 0.5 times or more the length of one side of the light emitting diode 200. In this case, the region where the first electrode 140 and the first conductivity type semiconductor layer 111 are in contact with each other can be increased, so that the current flowing from the first electrode 140 to the first conductivity type semiconductor layer 111 can be more effectively So that the forward voltage can be further reduced.

The first contact region R ₁ and the second contact region R ₂ may be formed using photolithography and etching techniques. For example, an etching region is defined by using a photoresist, and the second conductive type semiconductor layer 113 and the active layer 112 are etched by dry etching such as ICP to form first contact regions R ₁ and R ₂ 2 contact region R ₂ may be formed.

The second electrode 120 is disposed on the second conductive type semiconductor layer 113 and can be electrically connected to the second conductive type semiconductor layer 113. The second electrode 120 is formed on the mesa M and may have the same shape according to the shape of the mesa M. The second electrode 120 includes a reflective metal layer 121 and may further include a barrier metal layer 122 and the barrier metal layer 122 may cover the upper surface and side surfaces of the reflective metal layer 121. The barrier metal layer 122 may be formed to cover the upper surface and the side surface of the reflective metal layer 121 by forming a pattern of the reflective metal layer 121 and forming the barrier metal layer 122 thereon. For example, the reflective metal layer 121 may be formed by depositing and patterning Ag, Ag alloy, Ni / Ag, NiZn / Ag, and TiO / Ag layers. The barrier metal layer 122 may be formed of Ni, Cr, Ti, Pt, Au or a composite layer thereof. Specifically, the barrier metal layer 122 may be formed of Ni / Ag / [Ni / Ti] ² / Au / Ti. More specifically, at least a part of the upper surface of the second electrode 120 may include a Ti layer having a thickness of 300 ANGSTROM. When the area of the upper surface of the second electrode 120 in contact with the first insulating layer is made of a Ti layer, adhesion between the first insulating layer 130 and the second electrode 120, which will be described later, Can be improved. Thereby preventing the metallic material of the reflective metal layer 121 from being diffused or contaminated. The second electrode 120 may include a transparent conductive film such as indium tin oxide (ITO) or zinc oxide (ZnO). ITO is made of a metal oxide having a high light transmittance, so that absorption of light by the second electrode 120 can be suppressed and the luminous efficiency can be improved. The electrode protection layer 160 may be disposed on the second electrode 120 and the electrode protection layer 160 may be formed of the same material as that of the first electrode 140, However, it is not limited thereto.

The first insulating layer 130 may be disposed between the first electrode 140 and the mesa M, The first electrode 140 and the mesa M may be insulated through the first insulating layer 130 and the first electrode 140 and the second electrode 120 may be insulated. The first insulating layer 130 may partially expose the first contact region R ₁ and the second contact region R ₂ . The first insulating layer 130 may expose a portion of the second contact region R ₂ through the opening 130a and the first insulating layer 130 may be formed on the first conductive semiconductor layer 111, At least a part of the first contact region R ₁ may be exposed, covering only a part of the first contact region R ₁ between the outer portion of the first contact region R ₁ and the mesa M. 1 and 2, the first may be an insulating layer 130 is disposed along the periphery of the second contact area, a second contact region (R ₂₎ on a (R _2). At the same time, the first insulating layer 130 may be disposed adjacent to the mesa M rather than a region where the first contact region R ₁ and the first electrode 140 are in contact with each other. Specifically, the first insulation layer 130 may be disposed within the light emitting diode 200 rather than a region where the first contact region R ₁ and the first electrode 140 are in contact with each other. In this case, the contact area between the first electrode 140 and the first conductive type semiconductor layer 111 can be increased without reducing the light emitting area. In addition, in the dicing process of separating the wafer-type light emitting diodes 200 into the individual light emitting diodes 200, cracks are generated in the first insulating layer 130 disposed on the outer periphery of the first conductivity type semiconductor layer 111, Can be prevented. Therefore, the peeling force of the first electrode 140 or the second insulating layer 150, which will be described later, can be prevented from being weakened due to penetration of contaminants such as moisture through cracks, The reliability of the light emitting diode 200 can be enhanced. The first insulating layer 130 may have an opening 130b for exposing the second electrode 120, which will be described later. The second electrode 120 can be electrically connected to the pad or the bump through the opening 130b.

The first insulating layer 130 may include a preliminary insulating layer 131 and a main insulating layer 132 as shown in FIG.

The preliminary insulating layer 131 is formed on the upper surface of the mesa m and on the first conductive semiconductor layer 111 so that the region where the second electrode 120 is formed and the region of the first conductive semiconductor layer 111 exposed To cover at least a part of the region where the semiconductor device is formed. Further, the preliminary insulating layer 131 may further cover the side surface of the mesa M, and further, may partially cover the upper surface of the mesa M. The preliminary insulating layer 131 may be in contact with the second electrode 120 and may be spaced apart. When the preliminary insulating layer 131 is separated, the second conductive semiconductor layer 113 is partially exposed between the preliminary insulating layer 131 and the second electrode 120. The preliminary insulating layer 131 may be formed of SiO ₂ , SiN _x , MgF ₂ And the like. Further, the preliminary insulating layer 131 may include multiple layers and may include a distributed Bragg reflector in which materials having different refractive indices are alternately stacked.

Alternatively, the preliminary insulating layer 131 may be formed prior to the formation of the second electrode 120, may be formed after the formation of the second electrode 120, or may be formed during the formation of the second electrode 120 have. For example, when the second electrode 120 includes a conductive oxide layer and a reflective layer including a metal disposed on the conductive oxide layer, a conductive oxide layer may be formed on the second conductive type semiconductor layer 225, The preliminary insulating layer 131 may be formed before forming the preliminary insulating layer 131. [ At this time, the conductive oxide layer contacts ohmic contact with the second conductive type semiconductor layer 225, and the preliminary insulating layer 131 may have a thickness of 400 to 2000 Å. In another embodiment, the pre-insulating layer 131 may be formed prior to the formation of the second electrode 120, in which case the second electrode 120 may form an ohmic contact with the second conductive semiconductor layer 113 And may include a reflective layer formed of a metal material. In these embodiments, the preliminary insulating layer 131 is formed before the formation of the reflective layer including the metal material, thereby preventing the light reflection factor of the reflective layer from increasing due to the diffusion of the material between the reflective layer and the light emitting structure 220, can do. In addition, in the process of forming the reflective layer including the metal material, it is possible to prevent a problem such as an electric short which may occur due to the metal material remaining in another portion where the second electrode 120 is not formed.

The main insulating layer 132 may be disposed so as to cover the preliminary insulating layer 131. The main insulating layer 132 may be formed through a known deposition method such as PECVD or E-beam evaporation. The main insulating layer 132 may be formed to cover the first conductive semiconductor layer 111, the mesa M, and the second electrode 120 as a whole, and may be provided in the form of FIG. 4 through a patterning process . The patterning process may include a photolithography process or a lift-off process. The main insulating layer 132 is made of SiO ₂ , SiN _x , MgF ₂ And the like. Further, the main insulating layer 132 may comprise multiple layers and may include a distributed Bragg reflector in which materials of different refractive index are alternately stacked. In addition, the main insulating layer 132 may have a thicker thickness than the pre-insulating layer 131, and may be, for example, 1000 to 18000 ANGSTROM.

As described above, the first insulating layer 130 may be formed in the shape of FIG. 1 through FIG. 4 by an etching process. At this time, a part of the upper surface of the second electrode 120 may be removed during the etching process, so that the thickness of the second electrode 120 may be reduced. Specifically, the etching process may remove the exposed surface of the second electrode 120 exposed by the opening 130b of the first insulating layer 130 by a predetermined thickness. More specifically, the Ti layer including the exposed surface of the second electrode 120 can be removed by the etching process. Therefore, the surface of the second electrode 120, which is in contact with the first insulating layer 130, is still excellent in adhesion between the second electrode 120 and the first insulating layer 130 due to the unremoved Ti layer. have. At the same time, in the remaining region of the second electrode 120 to which the external current is applied, the connection resistance can be lowered due to the removal of the Ti layer, so that the forward voltage can be reduced.

1 to 4 by the etching process, the top surface of the exposed first conductive type semiconductor layer 111 may be further etched. More specifically, after the main insulating layer 132 is formed, an etching process can be performed on a region of the first contact region L ₁ and the second contact region L ₂ that is not covered by the first insulating layer 130 have. Accordingly, the thickness of the portion of the first conductivity type semiconductor layer 111 that is not disposed under the first insulating layer 130 may be smaller than the thickness of the portion disposed below the first insulating layer 130. Particles remaining on the exposed first conductive type semiconductor layer 111 out of particles derived from an inert gas such as CF 4 used in the etching process of the first insulating layer 130 can be removed. The adhesion between the first electrode 140 and the first conductive type semiconductor layer 111 can be improved and the connection resistance between the first electrode 140 and the first conductive type semiconductor layer 111 can be reduced.

4, the preliminary insulating layer 131 is not disposed on the second electrode 120 and extends from the upper surface of the second conductivity type semiconductor layer 113 to form the upper surface of the first conductivity type semiconductor layer 111 The thickness 130T ₁ of the first insulating layer 130 disposed on the upper surface of the second electrode 120 is greater than the thickness 130T ₁ of the first insulating layer 130 disposed on the upper surface of the second conductive semiconductor layer 113 May be less than the thickness (130T ₂ ). The thickness 130T ₂ of the first insulating layer 130 disposed on the upper surface of the second conductive type semiconductor layer 113 is greater than the thickness 130T ₂ of the first insulating layer 130 disposed on the upper surface of the first conductive type semiconductor layer 111, May be the same as the thickness (130T ₃ ). Therefore, since the first insulating layer 130 can cover the side surface of the mesa M without reducing its thickness, the damage of the first insulating layer 130 on the side of the mesa M is reduced, Can be prevented.

The first electrode 140 may be disposed on the first insulating layer 130. Specifically, the first electrode 140 may cover most of the first insulating layer 130. The first electrode 140 may contact at least a portion of the first contact region R ₁ and at least a portion of the second contact region R ₂ . And may be electrically connected to the first conductive type semiconductor layer 111. The first electrode 140 may expose an outer edge of the first contact region. 1 and 2, an area where the first contact area R ₁ and the first electrode 140 are in contact is smaller than a contact area between the first contact area R ₁ and a second insulating layer 150 May be disposed adjacent to the mesa (M). The region where the first contact region R ₁ and the first electrode 140 are in contact with each other is closer to the inside of the light emitting diode 200 than the region where the first contact region R ₁ and the second insulating layer 150, As shown in FIG. In this case, since the first electrode 140 is not exposed to the side surface of the light emitting diode 200, the first electrode 140 can be effectively protected from contaminants such as moisture from the outside. Also, the first electrode 140 may contact a portion of the second contact region R ₂ , and the contacting surface may be linear.

The first line width L ₁ which is the line width of the region where the first contact region R ₁ and the first electrode 140 are in contact is the line width of the region in which the second contact region R ₂ and the first electrode 140 are in contact And may be larger than the second line width L ₂ . As a result, the area of the first electrode 140 and the first conductive type semiconductor layer 111 contacting with each other is relatively increased through the first contact region R ₁ and the forward voltage of the light emitting diode 200 is reduced have. Further, the current can be more effectively dispersed in the horizontal direction, and the luminous efficiency can be improved. Specifically, the first line width L ₁ may exceed 10 탆, and the second line width L ₂ may be 10 탆 or less. For example, the first line width L ₁ may be 11 μm and the second line width L ₂ may be 10 μm.

The first electrode 140 may also be disposed on the second electrode 120, which will be described later, through the opening 130b, as illustrated, which corresponds to an example of the electrode protection layer 160 described above. The first electrode 140 contacting the first contact region R ₁ and the second contact region R ₂ is disposed on the second electrode 120 to be described later by the second insulating layer 150 And may be electrically insulated from the electrode protection layer 160. In this case, when the solder composed of AuSn or the like is used for electrical connection, the first electrode 140 can be prevented from diffusing the solder material into the second electrode 120, and the first electrode 140 and the second electrode The step between the electrodes 120 can be reduced, so that the light emitting diode 200 can be more stably attached to the circuit member such as the printed circuit board.

The first electrode 140 may include a highly reflective metal layer such as an Al layer and the highly reflective metal layer may be formed on an adhesive layer such as Ti, Cr, or Ni. Further, a protective layer of a single layer or a multiple layer structure such as Ni, Cr, Au or the like may be formed on the highly reflective metal layer. The first electrode 140 may have a multi-layer structure of Cr / Ti / Al / Ti / Ni / Au. Specifically, the first electrode 140 may be formed of Cr / Al / Ti / Ni] ² / Ti / Ni / Au / Ti. More specifically, the upper surface of the first electrode 140 may include a Ti layer of 100 Å thick. When the upper surface is made of a Ti layer, adhesion between the second insulating layer 150 and the first electrode 140, which will be described later, is improved, and reliability of the light emitting diode 200 can be improved. The first electrode 140 may be formed by depositing a metal material and patterning the metal material.

The second insulating layer 150 may contact a part of the first contact region Rl. Specifically, the first contact region R ₁ exposed by the first electrode 140 can be covered. In addition, the second insulating layer 150 may cover at least a part of the first electrode 140. The second insulating layer 150 may have an opening 150a for exposing the first electrode 140 and an opening 150b for exposing the second electrode 120 to be described later. The second insulating layer 150 may be disposed between the first electrode 140 and the electrode protecting layer 160 when the light emitting diode 200 includes the electrode protecting layer 160. Accordingly, insulation between the first electrode 140 and the electrode protection layer 160 can be further secured. The second insulating layer 150 may be formed by depositing and patterning an oxide insulating layer, a nitride insulating layer, or a polymer such as polyimide, Teflon, or parylene on the first electrode 140.

The second insulating layer 150 may be formed by a known deposition method such as PECVD or E-beam evaporation. In this case, the second insulating layer 150 may be formed to cover the first conductive semiconductor layer 111 and the first electrode 140 as a whole, and may be provided in the form of FIG. 1 through FIG. 4 through a patterning process. The patterning process may include a photolithography process or a lift-off process.

A part of the upper surface of the first electrode 140 may be removed during the patterning process of the second insulating layer 150 so that the thickness of the first electrode 140 may be reduced. Specifically, the etching process may remove the exposed surface of the first electrode 140 exposed by the openings 150a and 150b of the second insulating layer 150 by a predetermined thickness. More specifically, the Ti layer including the exposed surface of the first electrode 140 can be removed by the etching process. Therefore, the surface of the first electrode 140, which is in contact with the second insulating layer 150, may have a good adhesive force between the first electrode 140 and the second insulating layer 150 due to the unremoved Ti layer. have. At the same time, in the remaining region of the first electrode 140 connected to the external electrode by solder or the like, the connection resistance can be lowered due to the removal of the Ti layer, so that the forward voltage can be reduced. The entire surface of the side surface of the first conductivity type semiconductor layer 111 and a part of the side surface of the growth substrate 100 can be covered. As a result, the first conductivity type semiconductor layer 111 can be protected from external moisture or impact, and the interface between the growth substrate 100 and the first conductivity type semiconductor layer 111 can be prevented from spreading, The reliability of the light emitting diode 200 can be improved.

The second insulating layer 150 may cover at least a part of the inclined surface of the growth substrate 100. As a result, the second insulating layer 150 can be effectively attached to the growth substrate 100, so that the peeling force is increased and the reliability of the light emitting diode 200 can be improved. The inclined plane can be formed in the dicing process of dividing the wafer into individual light emitting diodes 200 in the course of laser penetrating the growth substrate.

FIG. 5 is a cross-sectional view of a circuit member on which a light emitting diode and a light emitting diode are mounted according to an embodiment of the present invention, FIG. 6 is an enlarged view of a portion I ₂ of FIG. 5, an enlarged view of the (I _3), Figure 8 is a sectional view illustrating the shape of the circuit members mounted on the light emitting diode according to an embodiment of the present invention in detail.

As shown in FIG. 5, the plurality of light emitting diodes 200 may be mounted on the circuit member 300, and further, may be used as one module. The circuit member 300 may be a printed circuit board (PCB), but is not limited thereto. The circuit member 300 may include the base 310 and the wirings 321 and 322 as shown, but the shape thereof is not limited to that shown in Fig.

6, the light emitting diode 200 may be mounted on the circuit member through the pads 170 and 180. Specifically, the pads 170 and 180 may be connected to the light emitting diode 200 and the wiring 321, 322, respectively. The pads 170 and 180 may be, but are not limited to, solder or eutectic metal. Specifically, AuSn may be used as the eutectic metal.

7, the pads 170 and 180 may be in contact with the first electrode 140 and the second electrode 120, respectively, and the electrode protection layer 160 may be disposed on the second electrode 120 The first electrode 140 and the electrode protection layer 160 can be in contact with each other. The exposed Ti layer 140a of the first electrode 140 and the second electrode 120 is etched by the etching process at the time of forming the first insulating layer 130 and the second insulating layer 150, The pads 170 and 180 can be in contact with the first electrode 140 and the second electrode 120 from which the Ti layer 140a is removed, respectively. The Au layer 140b may be exposed because the Ti layer 140a is removed from the first electrode 140 and the second electrode 120 and the exposed Au layer 140b and the pads 170, 180 can be contacted. When the electrode protection layer 160 is disposed on the second electrode 120 and the electrode protection layer 160 is formed of the same material as the first electrode 140, So that the exposed Au layer and the pad 180 can be in contact with each other.

Referring to FIG. 8, eutectic metals may be used for the pads 170 and 180. In this case, the pads 170 and 180 may be a material containing Au, for example, AuSn. As a result, the Au component of the pads 170 and 180 can contact the first electrode 140 and the second electrode 120 or the Au layer of the first electrode 140 and the electrode protection layer 160, The adhesion between the diode 200 and the pads 170 and 180 can be increased. Thus, the reliability of the circuit member on which the light emitting diode 200 is mounted can be improved.

9 is a plan view for explaining a light emitting diode 201 according to another embodiment of the present invention, FIG. 10 is a sectional view taken along the cutting line AB-B'-A 'in FIG. 9, FIG. 3 is a side view of the light emitting diode 201 of FIG. The light emitting diode 201 of FIG. 9 is similar to the light emitting diode 200 described with reference to FIGS. 1 to 4 except that the second insulating layer 150 is disposed apart from the outer periphery of the first conductivity type semiconductor layer 111 And the growth substrate 100 includes at least one modified region 100R.

Specifically, the growth substrate 100 may include at least one modified region 100R having a strip shape extending in the horizontal direction on at least one side of the growth substrate 100. [ The modified region 100R may be formed in the process of separating the growth substrate 100 and individualizing the device. For example, the modified region 100R can be formed by processing the growth substrate 100 using an internal processing method. The scribing surface can be formed inside the growth substrate 100 through the internal processing laser. At this time, the distance from the modified region 100R to the lower surface of the growth substrate 100 may be smaller than the distance from the modified region 100R to the upper surface of the growth substrate 100. Considering the light emitted to the side of the light emitting diode 201, laser processing is performed on the lower side of the growth substrate 100 to form the modified region 100R at a lower position relative to the growth substrate 100, It is possible to improve the extraction efficiency of the emitted light to the outside. In addition, if the modified region 100R is formed close to the first conductive type semiconductor layer 111, the nitride based semiconductor may be damaged during the laser processing step, thereby causing a problem in electrical characteristics. Therefore, by forming the modified region 100R so as to lie below the growth substrate 100, it is possible to prevent the reliability of the light emitting diode 201 and the degradation of the luminous efficiency due to the damage of the nitride-based semiconductor.

The second insulating layer 150 may be spaced apart from the outer periphery of the first conductive type semiconductor layer 111. [ The second insulating layer 150 may not be disposed on the side surfaces of the first conductivity type semiconductor layer 111 and the side surface of the growth substrate 100, And may be spaced apart from each other by a predetermined distance. Accordingly, in the process of separating the growth substrate 100 and individualizing the devices, the first insulation layer 150 can be prevented from being damaged by the stress applied to the interface of the individual light emitting diodes to be separated.

10 is a plan view for explaining a light emitting diode 202 according to yet another embodiment of the present invention, and FIG. 11 is a sectional view taken along a perforated line A-B-B'-A 'of FIG.

The light emitting diode 202 of FIGS. 3 and 4 is similar to the light emitting diode 200 described with reference to FIGS. 1 and 2, except that a region where the first contact region R ₁ and the first electrode 140 are in contact with each other is 1 conductive semiconductor layer is disposed along the entire outer periphery of the upper surface of the one-conductivity-type semiconductor layer. More specifically, the region where the first contact region R ₁ and the first electrode 140 are in contact with each other may be arranged to be adjacent to all four sides of the first conductivity type semiconductor layer 111, and the mesa M may be completely surrounded It can be rice. In this case, the region where the first electrode 140 and the first conductivity type semiconductor layer 111 are in contact with each other can be increased, so that the current flowing from the first electrode 140 to the first conductivity type semiconductor layer 111 can be more effectively So that the forward voltage can be further reduced.

14 is a plan view for explaining a light emitting diode 203 according to another embodiment of the present invention, FIG. 15 is a sectional view taken along line A-A 'in FIG. 14, and FIG. 16 is a cross- ≪ / RTI >

The light emitting diode 203 of Figs. 14-16 is similar to the light emitting diode 200 described with reference to Figs. 1 and 2, but differs in the form of a mesa M.

Specifically, the mesa M of the light emitting diode 200 illustrated in FIGS. 1 and 2 includes a plurality of protrusions protruding toward one side of the light emitting diode 200. On the other hand, the light emitting diode 203 of FIGS. 14 to 16 has a plurality of protrusions protruding toward one side of the first conductivity type semiconductor layer 111, as well as a plurality of protrusions protruding toward the other side And may further include a plurality of protruding protrusions.

As a result, the second contact region R ₂ partially surrounded by the mesa M can be extended. That is, a second contact region R ₂ disposed between the plurality of protrusions protruding toward the other side, which is disposed in a direction opposite to one side of the first conductivity type semiconductor layer 111, can be further secured. As a result, not only in the region adjacent to one side of the first conductive semiconductor layer 111 but also in the region adjacent to the other side, on the second electrode 120 and the second contact region R ₂ on the protrusions The current can be smoothly moved between the first electrodes 140 arranged. Accordingly, the degree of light emission of the region adjacent to the other side can be improved.

17 is an exploded perspective view illustrating an example in which a light emitting diode according to an embodiment of the present invention is applied to a lighting apparatus.

Referring to FIG. 17, the illumination device according to the present embodiment includes a diffusion cover 1010, a light emitting diode module 1020, and a body part 1030. The body 1030 may receive the light emitting diode module 1020 and the diffusion cover 1010 may be disposed on the body 1030 to cover the upper portion of the light emitting diode module 1020.

The body part 1030 is not limited as long as it can receive and support the light emitting diode module 1020 and supply the electric power to the light emitting diode module 1020. For example, as shown, the body portion 1030 may include a body case 1031, a power supply 1033, a power supply case 1035, and a power connection 1037. [

The power supply unit 1033 is accommodated in the power supply case 1035 and is electrically connected to the light emitting diode module 1020, and may include at least one IC chip. The IC chip may control, convert or control the characteristics of the power supplied to the light emitting diode module 1020. The power supply case 1035 can receive and support the power supply device 1033 and the power supply case 1035 in which the power supply device 1033 is fixed can be located inside the body case 1031 . The power connection portion 115 is disposed at the lower end of the power source case 1035 and can be connected to the power source case 1035. [ The power connection unit 115 may be electrically connected to the power supply unit 1033 in the power supply case 1035 and may serve as a path through which external power may be supplied to the power supply unit 1033. [

The light emitting diode module 1020 includes a substrate 1023 and a light emitting diode 1021 disposed on the substrate 1023. The light emitting diode module 1020 is provided on the body case 1031 and may be electrically connected to the power supply unit 1033.

The substrate 1023 is not limited as long as it is a substrate capable of supporting the light emitting diode 1021, and may be, for example, a printed circuit board including wiring. The substrate 1023 may have a shape corresponding to the fixing portion on the upper portion of the body case 1031 so as to be stably fixed to the body case 1031. [ The light emitting diode 1021 may include at least one of the light emitting diodes according to the embodiments of the present invention described above.

The diffusion cover 1010 is disposed on the light emitting diode 1021 and may be fixed to the body case 1031 to cover the light emitting diode 1021. [ The diffusion cover 1010 may have a light-transmitting material and may control the shape and the light transmittance of the diffusion cover 1010 to control the directivity characteristics of the illumination device. Accordingly, the diffusion cover 1010 can be modified into various forms depending on the purpose and application of the illumination device.

18 is a cross-sectional view for explaining an example in which a light emitting diode according to an embodiment of the present invention is applied to a display device.

The display device of this embodiment includes a display panel 2110, a backlight unit BLU1 for providing light to the display panel 2110 and a panel guide 2100 for supporting the lower edge of the display panel 2110. [

The display panel 2110 is not particularly limited and may be, for example, a liquid crystal display panel including a liquid crystal layer. At the edge of the display panel 2110, a gate driving PCB for supplying a driving signal to the gate line may be further disposed. Here, the gate driving PCBs 2112 and 2113 are not formed on a separate PCB, but may be formed on a thin film transistor substrate.

The backlight unit (BLU1) includes a light source module including at least one substrate (2150) and a plurality of light emitting diodes (2160). Further, the backlight unit BLU1 may further include a bottom cover 2180, a reflection sheet 2170, a diffusion plate 2131, and optical sheets 2130. [

The bottom cover 2180 is opened upward and can accommodate the substrate 2150, the light emitting diode 2160, the reflection sheet 2170, the diffusion plate 2131, and the optical sheets 2130. In addition, the bottom cover 2180 can be engaged with the panel guide 2100. The substrate 2150 may be disposed under the reflective sheet 2170 and surrounded by the reflective sheet 2170. However, the present invention is not limited thereto, and it may be placed on the reflective sheet 2170 when the reflective material is coated on the surface. In addition, a plurality of substrates 2150 may be arranged so that a plurality of substrates 2150 are arranged side by side, but it is not limited thereto and may be formed as a single substrate 2150.

The light emitting diode 2160 may include at least one of the light emitting diodes according to the embodiments of the present invention described above. The light emitting diodes 2160 may be regularly arranged on the substrate 2150 in a predetermined pattern. Further, a lens 2210 is disposed on each of the light emitting diodes 2160, so that uniformity of light emitted from the plurality of light emitting diodes 2160 can be improved.

The diffusion plate 2131 and the optical sheets 2130 are placed on the light emitting diode 2160. The light emitted from the light emitting diode 2160 may be supplied to the display panel 2110 in the form of a surface light source via the diffusion plate 2131 and the optical sheets 2130.

As described above, the light emitting diode according to the embodiments of the present invention can be applied to the direct-type display device as in the present embodiment.

19 is a cross-sectional view illustrating an example in which a light emitting diode according to an embodiment is applied to a display device.

The display device having the backlight unit according to the present embodiment includes a display panel 3210 on which an image is displayed, and a backlight unit BLU2 disposed on the back surface of the display panel 3210 to emit light. The display device further includes a frame 240 supporting the display panel 3210 and storing the backlight unit BLU2 and covers 3240 and 3280 surrounding the display panel 3210. [

The display panel 3210 is not particularly limited and may be, for example, a liquid crystal display panel including a liquid crystal layer. At the edge of the display panel 3210, a gate driving PCB for supplying a driving signal to the gate line may be further disposed. Here, the gate driving PCB may not be formed on a separate PCB, but may be formed on the thin film transistor substrate. The display panel 3210 is fixed by the covers 3240 and 3280 located at the upper and lower portions thereof and the cover 3280 located at the lower portion can be engaged with the backlight unit BLU2.

The backlight unit BLU2 for providing light to the display panel 3210 includes a lower cover 3270 partially opened on the upper surface thereof, a light source module disposed on one side of the inner side of the lower cover 3270, And a light guide plate 3250 for converting the light into the plane light. The backlight unit BLU2 of the present embodiment is disposed on the light guide plate 3250 and includes optical sheets 3230 for diffusing and condensing light, a light guide plate 3250 disposed below the light guide plate 3250, And a reflective sheet 3260 that reflects the light toward the display panel 3210. [

The light source module includes a substrate 3220 and a plurality of light emitting diodes 3110 spaced apart from each other at a predetermined interval on one surface of the substrate 3220. The substrate 3220 is not limited as long as it supports the light emitting diode 3110 and is electrically connected to the light emitting diode 3110, for example, it may be a printed circuit board. The light emitting diode 3110 may include at least one light emitting diode according to the embodiments of the present invention described above. The light emitted from the light source module is incident on the light guide plate 3250 and is supplied to the display panel 3210 through the optical sheets 3230. Through the light guide plate 3250 and the optical sheets 3230, the point light source emitted from the light emitting diodes 3110 can be transformed into a surface light source.

As described above, the light emitting diode according to the embodiments of the present invention can be applied to the edge type display device as in the present embodiment.

20 is a cross-sectional view illustrating an example in which a light emitting diode according to an embodiment of the present invention is applied to a headlamp.

Referring to FIG. 20, the head lamp includes a lamp body 4070, a substrate 4020, a light emitting diode 4010, and a cover lens 4050. Furthermore, the head lamp may further include a heat dissipating unit 4030, a support rack 4060, and a connecting member 4040.

Substrate 4020 is fixed by support rack 4060 and is spaced apart on lamp body 4070. The substrate 4020 is not limited as long as it can support the light emitting diode 4010, and may be a substrate having a conductive pattern such as a printed circuit board. The light emitting diode 4010 is located on the substrate 4020 and can be supported and fixed by the substrate 4020. [ In addition, the light emitting diode 4010 may be electrically connected to an external power source through the conductive pattern of the substrate 4020. In addition, the light emitting diode 4010 may include at least one light emitting diode according to the embodiments of the present invention described above.

The cover lens 4050 is located on a path through which light emitted from the light emitting diode 4010 travels. For example, as shown, the cover lens 4050 may be spaced from the light emitting diode 4010 by a connecting member 4040 and may be disposed in a direction to provide light emitted from the light emitting diode 4010 . The directional angle and / or color of the light emitted from the headlamp to the outside by the cover lens 4050 can be adjusted. The connecting member 4040 may serve as a light guide for fixing the cover lens 4050 to the substrate 4020 and for arranging the light emitting diode 4010 to provide the light emitting path 4045. [ At this time, the connection member 4040 may be formed of a light reflective material or may be coated with a light reflective material. The heat dissipation unit 4030 may include a heat dissipation fin 4031 and / or a heat dissipation fan 4033 to discharge heat generated when the light emitting diode 4010 is driven.

As described above, the light emitting diode according to the embodiments of the present invention can be applied to a head lamp, particularly a headlamp for a vehicle, such as the present embodiment.

Claims (23)

A first conductive semiconductor layer;
A second conductivity type semiconductor layer disposed on the first conductivity type semiconductor layer, and an active layer disposed between the second conductivity type semiconductor layer and the first conductivity type semiconductor layer;
A first electrode disposed on the mesa,
The first conductivity type semiconductor layer may include a first conductivity type semiconductor layer,
A first contact region disposed around the mesa along the periphery of the first conductive semiconductor layer; And
A second contact region at least partially surrounded by the mesa,
The first electrode electrically connecting at least a portion of the first contact region and at least a portion of the second contact region,
Wherein a line width of an area in which the first contact area and the first electrode are in contact is greater than a line width of an area in which the second contact area is in contact with the first electrode. The method according to claim 1,
And the second contact region is connected to the first contact region. The method according to claim 1,
Wherein the length of the second contact region in the long axis direction is 0.5 times or more the length of one side of the upper surface of the first conductivity type semiconductor layer. The method according to claim 1,
Wherein the line width of the region in which the first contact region and the first electrode are in contact is more than 10 mu m,
And a line width of an area in which the second contact region and the first electrode are in contact with each other is 10 mu m or less. The method according to claim 1,
Further comprising a first insulating layer disposed between the first electrode and the mesa,
Wherein the first insulating layer partially exposes the first contact region and the second contact region. The method of claim 5,
Wherein the first insulating layer is disposed adjacent to the mesa in a region where the first contact region and the first electrode are in contact with each other. The method of claim 5,
Wherein the first electrode is in contact with the first contact region and the second contact region exposed by the first insulating layer, and exposes an outline of the first contact region. The method of claim 5,
Wherein a thickness of a portion of the first conductive type semiconductor layer not disposed below the first insulating layer is smaller than a thickness of a portion disposed below the first insulating layer. The method of claim 5,
Wherein a thickness of the first insulating layer disposed on the upper surface of the second conductive type semiconductor layer is equal to a thickness of the first insulating layer disposed on the upper surface of the first conductive type semiconductor layer. The method according to claim 1,
And a second insulating layer covering the second contact region exposed by the first electrode and the first electrode. The method of claim 10,
Wherein the first electrode is a composite layer composed of a plurality of layers,
Wherein a region of the upper surface of the first electrode in contact with the second insulating layer is a Ti layer. The method of claim 11,
Wherein the second insulating layer includes an opening for exposing the first electrode,
Wherein a region of the upper surface of the first electrode exposed by the opening of the second insulating layer is an Au layer. The method of claim 12,
And a first pad in contact with the first electrode,
Wherein the first pad is in contact with the exposed Au layer. The method of claim 5,
And a second electrode disposed on the second conductive type semiconductor layer and electrically connected to the second conductive type semiconductor layer, wherein the second electrode is insulated from the first electrode by the first insulating layer Light emitting diode. 15. The method of claim 14,
Wherein the thickness of the first insulating layer disposed on the upper surface of the second electrode is smaller than the thickness of the first insulating layer disposed on the upper surface of the second conductive type semiconductor layer. 15. The method of claim 14,
Wherein the second electrode is a composite layer comprising a plurality of layers,
Wherein a region of the upper surface of the second electrode in contact with the first insulating layer is a Ti layer. 18. The method of claim 16,
Wherein the first insulating layer includes an opening for exposing the second electrode,
Wherein a region of the upper surface of the second electrode exposed by the opening of the first insulating layer is an Au layer. 18. The method of claim 17,
And a second pad in contact with the second electrode,
And the second pad is in contact with the exposed Au layer. The method of claim 10,
And a growth substrate disposed under the first conductive type semiconductor layer. The method of claim 19,
And the second insulating layer covers a whole area of a side surface of the first conductivity type semiconductor layer and a part of a side surface of the growth substrate. The method of claim 19,
Wherein the growth substrate comprises at least one modified region having a banding phenomenon extending horizontally on at least one side of the growth substrate. 23. The method of claim 21,
And the second insulating layer is spaced apart from a periphery of the first conductive type semiconductor layer by a predetermined distance. The method according to claim 1,
The mesa includes a plurality of protrusions protruding toward one side of the first conductive semiconductor layer; And
And a plurality of protrusions protruding toward the other side disposed opposite to the one side surface.

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