KR20180126834A - Semiconductor device - Google Patents

Abstract

An embodiment of the present invention discloses a semiconductor device including: a semiconductor structure including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer arranged between the first conductive semiconductor layer and the second conductive semiconductor layer, and including a plurality of recesses passing through the second conductive semiconductor layer and the active layer and arranged to a partial region of the first conductive semiconductor layer; a first electrode arranged inside the recesses and electrically connected to the first conductive semiconductor layer; a second electrode arranged on a first surface of the second conductive semiconductor layer; a third electrode arranged on the second electrode; a reflective layer arranged on the second electrode and the third electrode; a first conductive layer electrically connected to the first electrode; and a second conductive layer electrically connected to the second electrode through the reflective layer, in which the second electrode is an illumination electrode, the third electrode includes Al, and the area ratio of the third electrode to the reflective layer is 1 : 0.8 to 1 : 1.3.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

Embodiments relate to semiconductor devices.

Semiconductor devices including compounds such as GaN and AlGaN have many merits such as wide and easy bandgap energy, and can be used variously as light emitting devices, light receiving devices, and various diodes.

Particularly, a light emitting device such as a light emitting diode or a laser diode using a semiconductor material of Group 3-5 or 2-6 group semiconductors can be applied to various devices such as a red, Blue, and ultraviolet rays. By using fluorescent materials or combining colors, it is possible to realize a white light beam with high efficiency. Also, compared to conventional light sources such as fluorescent lamps and incandescent lamps, low power consumption, , Safety, and environmental friendliness.

In addition, when a light-receiving element such as a photodetector or a solar cell is manufactured using a semiconductor material of Group 3-5 or Group 2-6 compound semiconductor, development of a device material absorbs light of various wavelength regions to generate a photocurrent , It is possible to use light in various wavelength ranges from the gamma ray to the radio wave region. It also has advantages of fast response speed, safety, environmental friendliness and easy control of device materials, so it can be easily used for power control or microwave circuit or communication module.

Accordingly, the semiconductor device can be replaced with a transmission module of an optical communication means, a light emitting diode backlight replacing a cold cathode fluorescent lamp (CCFL) constituting a backlight of an LCD (Liquid Crystal Display) display device, White light emitting diodes (LEDs), automotive headlights, traffic lights, and gas and fire sensors. In addition, semiconductor devices can be applied to high frequency application circuits, other power control devices, and communication modules.

In particular, a light emitting device that emits light in the ultraviolet wavelength range can be used for curing, medical use, and sterilization by curing or sterilizing action.

Recently, research on ultraviolet light emitting devices has been actively conducted. However, there is a problem that it is difficult to realize a vertical type ultraviolet light emitting device, and the light extraction efficiency is relatively low.

The embodiment provides a semiconductor device with improved light extraction efficiency.

The embodiment provides a semiconductor device having excellent current spreading.

The problems to be solved in the embodiments are not limited to these, and the objects and effects that can be grasped from the solution means and the embodiments of the problems described below are also included.

A semiconductor device according to an embodiment of the present invention includes a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, A semiconductor structure including a plurality of recesses penetrating the second conductivity type semiconductor layer and the active layer and disposed to a partial region of the first conductivity type semiconductor layer; A first electrode disposed inside the plurality of recesses and electrically connected to the first conductive semiconductor layer; A second electrode disposed on a first surface of the second conductive semiconductor layer; A third electrode disposed on the second electrode; A reflective layer disposed on the second electrode and the third electrode; A first conductive layer electrically connected to the first electrode; And a second conductive layer electrically connected to the second electrode through the reflective layer, wherein the second electrode is a light-transmitting electrode, the third electrode comprises Al, and the third electrode and the reflective layer The area ratio satisfies 1: 0.8 to 1: 1.3.

The reflective layer may include a plurality of first reflective layers having a first refractive index and a plurality of second reflective layers having a second refractive index.

The reflective layer may include a DBR (Distributed Bragg Reflector).

The third electrode may be disposed between the adjacent recesses.

The third electrode may include a plurality of holes, and the plurality of first electrodes may be disposed in the plurality of holes in a plane.

The holes may have a polygonal or circular shape.

The area ratio of the first surface of the second conductivity type semiconductor layer to the reflective layer may be 1: 0.3 to 1: 0.7.

The third electrode comprises a first layer comprising Al, a second layer disposed between the first layer and the second electrode, and a third layer disposed between the first layer and the second conductive layer, And the second layer includes at least one of Cr, Ti, and Ni, and the third layer may include at least one of Ni, Ti, Ni, Pt, W, Au and Ni.

The area of the second electrode may be larger than the area of the third electrode.

The area ratio of the first electrode and the first electrode of the second conductivity type semiconductor layer may be 1: 0.08 to 1: 0.15.

A first insulating layer disposed in the recess to isolate the first conductive layer from the active layer and the second conductive type semiconductor layer, and a second insulating layer disposed between the first conductive layer and the second conductive layer, . ≪ / RTI >

The first insulating layer may include an extension extending to the first surface.

The reflective layer may be filled in a spaced-apart region between the extension and the second electrode.

The third electrode may include a plurality of end portions extending to an edge of the first surface, and a rim electrode connecting the plurality of end portions.

The active layer can emit light in the ultraviolet wavelength range.

According to the embodiment, the light extraction efficiency is improved.

Further, the current dispersion efficiency is excellent, and the light output can be improved.

The various and advantageous advantages and effects of the present invention are not limited to the above description, and can be more easily understood in the course of describing a specific embodiment of the present invention.

1 is a conceptual view of a semiconductor device according to an embodiment of the present invention,
FIGS. 2A and 2B are views for explaining a configuration in which light output is improved in accordance with the number of recesses,
3 is a plan view of a semiconductor device according to an embodiment of the present invention,
Fig. 4 is a sectional view in the AA direction of Fig. 3,
5 is a cross-sectional view of a third electrode of the present invention,
6A is a view showing a state in which the third electrode absorbs ultraviolet light,
FIG. 6B is a graph showing the reflectance of various reflection layers with respect to light having a wavelength of 280 nm,
7 is a view showing a state in which the recess is surrounded by the unit electrode,
8 is an enlarged view of a portion A in Fig. 3,
Fig. 9 is a modification of Fig. 4,
10 is a modification of the third electrode of the present invention,
11 is a plan view of a semiconductor device according to another embodiment of the present invention,
Fig. 12 is a sectional view in the BB direction of Fig. 11,
13 is a cross-sectional view of a semiconductor device according to another embodiment of the present invention,
Fig. 14 is an enlarged view in the direction B in Fig. 13,
15 is a graph showing changes in aluminum composition according to the thickness of the semiconductor structure of the present invention,
16 is a conceptual view of a semiconductor device package according to an embodiment of the present invention.

The embodiments may be modified in other forms or various embodiments may be combined with each other, and the scope of the present invention is not limited to each embodiment described below.

Although not described in the context of another embodiment, unless otherwise described or contradicted by the description in another embodiment, the description in relation to another embodiment may be understood.

For example, if the features of configuration A are described in a particular embodiment, and the features of configuration B are described in another embodiment, even if the embodiment in which configuration A and configuration B are combined is not explicitly described, It is to be understood that they fall within the scope of the present invention.

In the description of the embodiments, in the case where one element is described as being formed "on or under" another element, the upper (upper) or lower (lower) or under are all such that two elements are in direct contact with each other or one or more other elements are indirectly formed between the two elements. Also, when expressed as "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

FIG. 1 is a conceptual diagram of a semiconductor device according to an embodiment of the present invention, and FIGS. 2A and 2B are views for explaining a configuration in which light output is improved in accordance with the number of recesses. FIG.

1, a semiconductor device according to an embodiment of the present invention includes a semiconductor structure 120 including a first conductive semiconductor layer 124, an active layer 126, and a second conductive semiconductor layer 127, A first electrode 142 electrically connected to the first conductivity type semiconductor layer 124 and a second electrode 246 electrically connected to the second conductivity type semiconductor layer 127.

The semiconductor structure 120 can output light in the ultraviolet wavelength range. For example, the semiconductor structure 120 may output UV-A at near-ultraviolet wavelength band, UV-B at the far ultraviolet wavelength band, UV-B at deep ultraviolet wavelength band, C can be output. The wavelength range can be determined by the composition ratio of Al of the semiconductor structure 120. [

Illustratively, the near ultraviolet light (UV-A) may have a wavelength in the range of 320 to 420 nm, the far ultraviolet light (UV-B) may have a wavelength in the range of 280 nm to 320 nm, The light of the wavelength band (UV-C) may have a wavelength in the range of 100 nm to 280 nm.

The semiconductor structure 120 is disposed between the first conductivity type semiconductor layer 124 and the second conductivity type semiconductor layer 127 and between the first conductivity type semiconductor layer 124 and the second conductivity type semiconductor layer 127 And an active layer 126.

The first conductive semiconductor layer 124 may be formed of a compound semiconductor such as Group III-V or Group II-VI, and the first dopant may be doped. The first conductive semiconductor layer 124 may be a semiconductor material having a composition formula of In _{x 1} Al _{y 1} Ga ₁ -x ₁ -y1 N (0? _{X1? 1} , 0 _{? Y1? 1} , 0? X1 + y1? For example, GaN, AlGaN, InGaN, InAlGaN, and the like. The first dopant may be an n-type dopant such as Si, Ge, Sn, Se, or Te. When the first dopant is an n-type dopant, the first conductivity type semiconductor layer 124 doped with the first dopant may be an n-type semiconductor layer.

The active layer 126 is disposed between the first conductive semiconductor layer 124 and the second conductive semiconductor layer 127. The active layer 126 is a layer where electrons (or holes) injected through the first conductive type semiconductor layer 124 and holes (or electrons) injected through the second conductive type semiconductor layer 127 meet. The active layer 126 transitions to a low energy level as electrons and holes recombine, and can generate light having ultraviolet wavelengths.

The active layer 126 may have any one of a single well structure, a multiple well structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum dot structure, or a quantum well structure. ) Is not limited to this.

The second conductivity type semiconductor layer 127 may be formed of a compound semiconductor such as a group III-V or II-VI group, and the second conductivity type semiconductor layer 127 may be doped with a second dopant. A second conductive semiconductor layer 127 is a semiconductor material having a compositional formula of _{In x5 Al y2 Ga 1 -x5- y2} N (0≤x5≤1, 0≤y2≤1, 0≤x5 + y2≤1) or AlInN , AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, or Ba, the second conductivity type semiconductor layer 127 doped with the second dopant may be a p-type semiconductor layer.

The semiconductor structure 120 according to an embodiment includes a plurality of recesses h1. The plurality of recesses h1 may be disposed on a portion of the first conductivity type semiconductor layer 124 through the active layer 126 on the first surface 127G of the second conductivity type semiconductor layer 127. [

The first electrode 142 may be disposed inside the recess h1 and electrically connected to the first conductive semiconductor layer 124. [ The first conductive layer 165 may be disposed in the plurality of recesses h1 to electrically connect the plurality of first electrodes 142. [ The first insulating layer 131 may be disposed inside the recess h1 to electrically isolate the first conductive layer 165 from the second conductive type semiconductor layer 127 and the active layer 126. [

The first insulating layer 131 may include a first opening 21. The first electrode 142 may be disposed in the first opening 21 of the first insulating layer 131 and electrically connected to the first conductive semiconductor layer 124.

The first electrode 142 is preferably spaced apart from the side surface of the recess h1 to ensure the yield and / or reliability of the semiconductor device. The first insulating layer 131 may be disposed between the first electrode 142 and the side surface of the recess h1 within the recess h1 to secure the reliability of the semiconductor device.

Therefore, when the diameter of the recess h1 is 20 mu m or more, a process margin for disposing the first electrode 142 and the first insulating layer 131 in the recess h1 can be ensured, Can be secured. In order to secure a proper area of the active layer 126, it is preferable that the diameter of the recesses h1 is 70 mu m or less. The diameter of the recess h1 may be the maximum diameter formed on the first surface 127G of the second conductivity type semiconductor layer 127. [

2A, when a GaN-based semiconductor structure 120 emits ultraviolet light, it may include aluminum. If the aluminum composition of the semiconductor structure 120 is increased, the current dispersion characteristics may deteriorate in the semiconductor structure 120 . In addition, when the active layer 126 emits ultraviolet rays including Al, the amount of light emitted to the side of the active layer 126 increases (TM mode) as compared with a GaN-based blue light emitting device. This TM mode can mainly occur in an ultraviolet semiconductor device.

The ultraviolet semiconductor device has a lower current dispersion characteristic than the blue GaN based semiconductor device. Therefore, the ultraviolet semiconductor device needs to arrange the first electrode 142 relatively larger than the blue GaN-based semiconductor device.

The higher the composition of aluminum, the worse the current dispersion characteristics may be. Referring to FIG. 2A, the current may be dispersed only at a neighboring point of each first electrode 142, and the current density may be drastically lowered at a distant point. Therefore, the effective light-emitting region P2 can be narrowed.

The effective light emitting region P2 can be defined as a region up to the boundary point where the current density is 40% or less based on the current density at the center of the first electrode 142 having the highest current density. For example, the effective light emitting region P2 can be adjusted according to the level of the injection current and the composition of Al within a range of 40 占 퐉 from the center of the recess h1.

The current density in the low current density region P3 is low and the amount of emitted light may be smaller than that in the effective light emitting region P2. Therefore, the first electrode 142 can be further disposed in the low current density region P3 having a low current density, or the light output can be improved by using the reflective structure.

Generally, in the case of a GaN-based semiconductor device emitting blue light, it is preferable to minimize the area of the recesses h1 and the first electrode 142 because the current dispersion characteristics are relatively good. The larger the area of the recesses h1 and the first electrode 142 is, the smaller the area of the active layer 126 is. However, in the embodiment, since the composition of aluminum is high and the current dispersion characteristics are relatively low, the area and / or number of the first electrode 142 is increased even if the area of the active layer 126 is sacrificed, Or it may be desirable to arrange the reflective structure in the low current density region P3.

Referring to FIG. 2B, when the number of recesses h1 increases to 48, the recesses h1 may be arranged in a zigzag manner instead of being arranged straight in the transverse direction. In this case, since the area of the low current density region P3 can be narrowed, most of the active layer 126 can participate in light emission.

When the number of the recesses h1 is 70 to 110, the current can be more efficiently dispersed, the operating voltage can be lowered and the light output can be improved. In the semiconductor device that emits UV-C, it is preferable to dispose 70 or more recesses h1 in order to secure electrical and optical characteristics. In order to secure the volume of the active layer 126 and secure optical characteristics It is preferable to arrange them to 110 or less.

Referring again to FIG. 1, the second electrode 246 may be disposed on the first surface 127G of the second conductive type semiconductor layer 127. The second electrode 246 may include a light-transmitting electrode having a relatively small ultraviolet light absorption.

The first electrode 142 and the second electrode 246 may be ohmic electrodes. The first electrode 142 and the second electrode 246 may be formed of one selected from the group consisting of ITO (indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tin oxide), IAZO (indium aluminum zinc oxide), IGZO ), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO Nitride), AGZO ZnO, ZnO, IrOx, RuOx, NiO, RuOx / ITO, Ni / IrOx / Au or Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ru, Mg, Zn, Pt, Au, and Hf. However, the present invention is not limited to these materials.

The third electrode 247 may be disposed under the second electrode 246. The third electrode 247 may be disposed between the second conductive layer 150 and the second electrode 246 to improve current injection efficiency. The third electrode 247 may be a non-conductive electrode including a metal.

However, when the third electrode 247 is made of a highly conductive material, the third electrode 247 may be a light-transmitting electrode. The third electrode 247 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide ZnO, ZnO, IrOx, AlGaO, AlGaO, AZO, ATO, GZO, IZO, RuOx, NiO, RuOx / ITO, Ni / IrOx / Au, or Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, Ru, , Au, and Hf. However, the present invention is not limited to these materials.

The reflective layer 248 may cover a portion of the second electrode 246 and a portion of the third electrode 247. Accordingly, the reflection layer 248 can reflect light emitted from the active layer 126 to improve light extraction efficiency. The reflective layer 248 may comprise an insulating material. The reflective layer 248 may be composed of a first reflective layer having a first refractive index and a second reflective layer having a second refractive index. Illustratively, the reflective layer 248 may be, but is not necessarily, a DBR (Distributed Bragg reflector). For example, the reflective layer 248 may be an insulating material such as HfOx, SixOy, SixNy, SiON, TiOx, or the like, and may include at least one of the insulating materials.

The second conductive layer 150 may be electrically connected to the plurality of third electrodes 247 through holes disposed in the reflective layer 248. In addition, the second conductive layer 150 may include a material having good adhesion to the first insulating layer 131. Illustratively, the second conductive layer 150 may be formed of at least one material selected from the group consisting of Cr, Al, Ti, Ni, and Au, and alloys thereof, and may be a single layer or a plurality of layers Lt; / RTI >

The second conductive layer 150 may be in contact with the first insulating layer 131 in some regions. When the second conductive layer 150 and the first insulating layer 131 are in contact with each other, a material having good adhesion between the second conductive layer 150 and the first insulating layer 131 is disposed, The problem of lowering the reliability due to heat can be solved.

The first insulating layer 131 may electrically isolate the first electrode 142 from the active layer 126 and the second conductive type semiconductor layer 127. The first insulating layer 131 may electrically isolate the second conductive layer 150 from the first conductive layer 165.

The first insulating layer 131 may include a plurality of first openings 21 penetrating the recess h1 and the first electrode 142 may be disposed in the first opening 21. [ The first insulating layer 131 may include a second opening 22 for electrically connecting the second electrode pad 166 and the second conductive layer 150. The widths of the first opening 21 and the second opening 22 may be different from each other.

The first insulating layer 131 may be formed of at least one selected from the group consisting of SiO ₂ , SixOy, Si ₃ N ₄ , Si _x N _y , SiO _x N _y , Al ₂ O ₃ , TiO ₂ , However, the present invention is not limited thereto. The first insulating layer 131 may be formed as a single layer or a multilayer. For example, the first insulating layer 131 may be an insulating material such as HfOx, SixOy, SixNy, SION, TiOx, or the like and may be a DBR (distributed Bragg reflector) having a multi-layer structure including at least one of the insulating materials. However, the first insulating layer 131 may include various reflective structures without being limited thereto.

When the first insulating layer 131 performs a reflecting function, light emitted toward the side surface of the active layer 126 may be reflected upward to improve light extraction efficiency. Since the ultraviolet semiconductor device has a relatively high light emission probability in a TM (Transverse Magnetic mode) mode that emits light laterally as compared with a semiconductor device that emits blue light, when the first insulating layer 131 is disposed on the side of the recess h1 As the number of recesses h1 increases, the light extraction efficiency may be more effective.

A second electrode pad 166 may be disposed on one side edge region of the semiconductor device. The upper surface of the second electrode pad 166 may be depressed at its central portion, and the upper surface may have a concave portion and a convex portion. A wire (not shown) may be bonded to the concave portion of the upper surface. Accordingly, the bonding area can be widened and the second electrode pad 166 and the wire can be bonded more firmly.

The second electrode pad 166 may act to reflect light, so that the closer the second electrode pad 166 is to the semiconductor structure 120, the better the light extraction efficiency can be.

The second electrode pad 166 may be higher than the active layer 126. Therefore, the second electrode pad 166 can reflect the light emitted in the horizontal direction of the device from the active layer 126 to improve the light extraction efficiency and control the directivity angle.

The second electrode pad 166 may be electrically connected to the second conductive layer 150 and the second electrode 246 through the second opening 22 of the first insulating layer 131.

The width of the second opening 22 of the first insulating layer 131 may be 60% or more of the entire width of the second electrode pad 166 to secure the electrical characteristics of the semiconductor element, It may be less than 95% to ensure efficiency.

For example, the second opening 22 preferably has a width of 40 mu m or more in order to secure the electrical characteristics of the semiconductor device. Since the second electrode pad 166 is not a portion contributing to light emission in the area of the upper surface of the semiconductor element, it is preferable to arrange the second electrode pad 166 so that the area for the wire process is secured and the electrical characteristics of the semiconductor element are secured.

It is preferable that the width of the second electrode pad 166 for the wire process be 40 m or more in order to secure electrical characteristics by current injection of the semiconductor element. It is also preferable to arrange the semiconductor device so that the area of the non-emission region between the area of the semiconductor device and the area of the light emitting structure is 120 mu m or less.

At least one second electrode pad 166 may be disposed, and a width of the second electrode pad 166 may be a width of a single second electrode pad 166.

Considering the width of the second electrode pad 166, if the width of the second opening 22 is greater than 120 μm, the second conductive layer 150 may be exposed to the outside. When the second conductive layer 150 is exposed to the outside, the current injection characteristics of the second conductive layer 150 may be degraded due to external moisture or contaminants. Therefore, in order not to expose the second conductive layer 150 to the outside, it is preferable that the width of the second opening 22 is 120 μm or less.

The second insulating layer 132 may electrically isolate the second conductive layer 150 from the first conductive layer 165. The first conductive layer 165 may be electrically connected to the first electrode 142 through the second insulating layer 132.

The thickness of the first insulating layer 131 may be thicker than that of the second electrode 246 and may be thinner than the thickness of the second insulating layer 132. Illustratively, the first insulating layer 131 may have a thickness of 300 nm to 700 nm. In order to ensure electrical reliability of the semiconductor device, the thickness of the first insulating layer 131 may be 300 nm or more. In addition, when the second conductive layer 150 is disposed on the top and side surfaces of the first insulating layer 131, the step coverage characteristics of the second conductive layer 150 may be poor and may cause peeling or cracking. If peeling or cracking is caused, the electrical reliability may deteriorate or the light extraction efficiency may deteriorate. Therefore, in order to secure the electrical and optical characteristics and reliability of the semiconductor device, it is preferable that the thickness of the first insulating layer 131 is 700 nm or less.

The thickness of the second insulating layer 132 may be 400 nm to 1000 nm. The thickness of the second insulating layer 132 may be less than or equal to 400 nm because the electrical and optical reliability of the second insulating layer 132 may be lowered due to heat generated during operation of the semiconductor device or migration and agglomeration of materials constituting the electrode. May be preferred. In addition, it may be preferable to arrange the element to be 1000 nm or less in order to improve the reliability of the device due to the pressure or thermal stress applied to the device during the process, and to improve the process cost.

The first conductive layer 165 and the bonding layer 160 may be disposed along the bottom surface of the semiconductor structure 120 and the shape of the recess h1. The first conductive layer 165 may be made of a material having a high reflectivity. Illustratively, the first conductive layer 165 may comprise aluminum. When the first conductive layer 165 includes aluminum, it functions to reflect light emitted from the active layer 126 to the upper portion, thereby improving light extraction efficiency.

The bonding layer 160 may include a conductive material. Illustratively, the bonding layer 160 may comprise a material selected from the group consisting of gold, tin, indium, aluminum, silicon, silver, nickel, and copper, or alloys thereof. The bonding layer 160 may bond the substrate 170 and the semiconductor structure 120 during the LLO process.

The substrate 170 may be made of a conductive material. Illustratively, substrate 170 may comprise a metal or semiconductor material. The substrate 170 may be a metal having excellent electrical conductivity and / or thermal conductivity. In this case, the heat generated during semiconductor device operation can be quickly dissipated to the outside.

The substrate 170 may comprise a material selected from the group consisting of silicon, molybdenum, silicon, tungsten, copper, and aluminum, or alloys thereof. The substrate 170 may electrically connect the first conductivity type semiconductor layer 124 to the external electrode.

A passivation layer 180 may be formed on the top surface and side surfaces of the semiconductor structure 120. The passivation layer 180 may be in contact with the first insulation layer 131 at a region adjacent to the second electrode 246 or at a lower portion of the second electrode 246.

Unevenness may be formed on the upper surface of the semiconductor structure 120. Such unevenness can improve the extraction efficiency of light emitted from the semiconductor structure 120. The average height may vary depending on the wavelength of ultraviolet light. In the case of UV-C, the height of the unevenness is about 300 nm to 800 nm, and the light extraction efficiency can be improved when the average height is 500 nm to 600 nm.

FIG. 3 is a plan view of a semiconductor device according to an embodiment of the present invention, FIG. 4 is a cross-sectional view taken along the line AA of FIG. 3, FIG. 5 is a cross-sectional view of a third electrode of the present invention, FIG. 6B is a graph showing the reflectance of various reflection layers measured at 280 nm wavelength band. FIG.

Referring to FIG. 3, the third electrode 247 may be disposed between adjacent recesses h1 on a plane. The third electrode 247 may include a plurality of holes S1 and the plurality of recesses h1 may be disposed inside the plurality of holes S1.

The plurality of holes S1 may have a polygonal shape such as a triangle, a square, or a pentagon, or may have a circular shape. However, the present invention is not limited thereto, and a plurality of holes may have various shapes.

4, the first insulating layer 131 includes an extension 131a extending to the first surface 127G of the second conductive type semiconductor layer 127, and the second electrode 246 includes an extension 131b 2-conductivity type semiconductor layer 127 can be disposed on the first surface 127G.

A spacing W2 may be formed between the first insulating layer 131 and the second electrode 246 and the second conductive semiconductor layer 127 may be partially exposed through the spacing W2. A reflective layer 248 may be disposed in the spacing region W2 to contact the second conductivity type semiconductor layer 127. [ When the reflective layer 248 contacts the second conductive semiconductor layer 127, the reflective layer 248 surrounds the second electrode 246, thereby preventing a peeling problem between the second electrode 246 and the reflective layer 248 It is possible to improve the reliability of the semiconductor device.

The third electrode 247 may be disposed under the second electrode 246. The third electrode 247 may be disposed between the second conductive layer 150 and the second electrode 246 to improve current injection efficiency. If the second conductive layer 150 is directly connected to the second electrode 246 without the third electrode 247, since the reflective layer 248 is nonconductive, the thickness of the second electrode 246 may be thicker Should be. If the thickness of the second electrode 246 is increased, the probability that the light emitted from the active layer 126 is absorbed by the second electrode 246 may increase, so that the optical characteristics of the semiconductor device may be deteriorated.

If the thickness of the second electrode 246 is less than 1 nm, the second electrode 246 may not be properly disposed, and the electrical characteristics may be deteriorated. If the thickness of the second electrode 246 is more than 15 nm, . The thickness of the third electrode 247 may be 200 nm to 1.0 탆, but is not limited thereto.

The reflective layer 248 may include a first hole 248a exposing a portion of the third electrode 247. [ The exposed third electrode 247 may be electrically connected to the second conductive layer 150.

The width of the first hole 248a may be narrower than the width of the third electrode 247. If the width of the first hole 248a is wider than the width of the third electrode 247, a space may be formed between the third electrode 247 and the reflective layer 248 to reduce the light extraction efficiency.

5, the third electrode 247 includes a first layer 247a including aluminum and a second layer 247b disposed between the second electrode 246 and the first layer 247a can do. The first layer 247a comprising Al may also function as a reflective layer 248 that reflects ultraviolet light. However, the adhesion between Al and ITO may not be sufficient to suppress the peeling phenomenon due to heat generated during operation of the semiconductor device or agglomeration or migration of other materials. Thus, the second layer 247b may serve to bond the first layer 247a to the second electrode 246. [ The second layer 247b may include at least one of chromium (Cr) and titanium (Ti) nickel (Ni).

A third layer 247c may be disposed under the first layer 247a. The third layer 247c may serve to prevent the atoms (aluminum) of the first layer 247a from migrating to neighboring layers or to bond with other layers. The third layer 247c may include at least one of Ni, Ti, No, Pt, W, Au, and Ni.

The third electrode can reflect ultraviolet light including Al, but the second layer absorbs ultraviolet light, so that the light extraction efficiency may not be good. As the area of the third electrode 247 increases, the absorption area of the second layer 247b increases and the light extraction efficiency may decrease as shown in FIG. 6A.

Therefore, in the embodiment, the DBR reflective layer 248 having a high reflectance of ultraviolet light can be used to enhance the reflection efficiency. Referring to FIG. 6B, when the ITO light-transmitting electrode is used as the second electrode and the DBR is used as the reflective layer, the reflectivity for 280 nm ultraviolet light is higher than that for the Al reflective layer.

However, since the DBR reflective layer 248 is nonconductive, the current injection area is small and the thickness of the second electrode 246 must be increased to increase the current dispersion efficiency. If the second electrode is thickened, there is a problem that the absorption rate of ultraviolet light increases. Therefore, in the embodiment, the thickness of the second electrode 246 can be controlled to be thin by dispersing the current using the third electrode 247.

According to the embodiment, as the area of the third electrode 247 increases, the current dispersion efficiency improves, but the light extraction efficiency may decrease. That is, the current dispersion efficiency and the light extraction efficiency may be in a trade-off relationship. Therefore, the proper area ratio of the third electrode 247 may be important.

The area ratio of the third electrode 247 to the reflective layer 248 may be 1: 0.8 to 1: 1.3. Here, the area of the third electrode 247 and the reflective layer 248 may be a maximum area on a plane.

When the area ratio is larger than 1: 0.8, the area of the reflective layer 248 increases and the light extraction efficiency can be improved. When the area ratio is less than 1: 0.8 (e.g., 1: 0.6), the area of the reflective layer 248 may be reduced and the light extraction efficiency may decrease.

Further, when the area ratio is less than 1: 1.3, it is possible to secure a sufficient area of the third electrode and improve the current dispersion efficiency. If the area ratio is larger than 1: 1.3, the area of the third electrode 247 relatively decreases, and the current dispersion efficiency may decrease.

The area ratio of the first surface 127G of the second conductivity type semiconductor layer 127 to the third electrode 247 may be 1: 0.3 to 1: 0.7. When the area ratio is larger than 1: 0.3, the area of the third electrode 247 is widened to have a sufficient current dispersion efficiency. When the area ratio is controlled to be 1: 0.7 or less, the light absorption by the third electrode 247 is improved . If the area ratio is less than 1: 0.3, the area of the third electrode 247 becomes small, and the current dispersion efficiency can be reduced. In addition, when the area ratio is larger than 1: 0.7, the light absorption area of the third electrode 247 increases and the light extraction efficiency can be reduced.

The area ratio of the first surface 127G of the second conductivity type semiconductor layer 127 to the first electrode 142 may be 1: 0.08 to 1: 0.15. If the area ratio is larger than 1: 0.08, the area of the first electrode 142 is widened to have a sufficient current dispersion efficiency. If the area ratio is controlled to 1: 0.15 or less, the light absorption by the first electrode 142 is improved . If the area ratio is smaller than 1: 0.08, the area of the first electrode 142 becomes small, and the current dispersion efficiency can be reduced. When the area ratio is larger than 1: 0.7, the interval between the first electrodes 142 is narrowed, and a sufficient area of the third electrodes 247 can not be secured. Therefore, the area of the third electrode 247 is narrowed, and the current dispersion efficiency can be reduced.

The area of the third electrode 247 may be smaller than the area of the second electrode 246. 4, the ratio W3: W1 of the width W3 of the second electrode 246 and the width W1 of the third electrode 247 disposed between adjacent recesses h1 is 1: 0.4 to 1: 0.8. If the ratio of width is less than 1: 0.4, the area of the third electrode becomes smaller and the current dispersion efficiency may decrease. If the width ratio is larger than 0.8, the light absorption area of the third electrode 247 increases, can do.

The tilt angle of the reflective layer 248 may be between 20 degrees and 80 degrees. When the inclination angle of the reflective layer 248 is less than 20 degrees, the thickness of the sufficient reflective layer 248 can not be maintained and the reflectance can be reduced. In addition, when the inclination angle is larger than 80 degrees, there is a problem that it is difficult to form the second conductive layer 150 on the side surface of the reflective layer 248.

FIG. 7 is a view showing a state in which the recess is surrounded by a unit electrode, and FIG. 8 is an enlarged view of a portion A in FIG.

Referring to Fig. 7, each of the recesses h1 may be disposed inside the unit electrode 247-1. The third electrode 247 may be an aggregate of the unit electrodes 247-1 surrounding the respective recesses h1. The unit electrodes 247-1 may be integrally formed to share side walls, but are not limited thereto. Illustratively, the unit electrodes 247-1 may be disposed apart from each other.

The area ratio of the holes S1 partitioned by the recesses h1 and the unit electrodes 247-1 may be 1: 2.0 to 1: 5.0. If the area ratio is less than 1: 2.0, the area of the reflective layer 248 may be reduced and the light extraction efficiency may decrease. If the area ratio is larger than 1: 5.0, the area of the reflective layer 248 is increased instead of the area of the reflective electrode 248, There is a problem that dispersion efficiency is low.

Referring to FIG. 8, the distance d1 between the third electrode 247 and the side surface of the semiconductor structure 120 may be 1.0 탆 to 10 탆. If the separation distance d1 is smaller than 1.0 占 퐉, it may be difficult to secure the process margin. In addition, when the separation distance d1 is larger than 10 mu m, the current dispersion efficiency on the side surface may be lowered. However, the present invention is not limited thereto, and a third electrode 247 may be formed to the side surface of the semiconductor structure 120.

Fig. 9 is a modification of Fig. 4, and Fig. 10 is a modification of the third electrode of the present invention.

Referring to FIG. 9, the reflective layer 248 may extend into the recess h1 along the first insulating layer 131. Referring to FIG. According to this structure, since the reflection layer 248 is disposed inside the recess h1, the light emitted in the TM mode from the active layer 126 can be reflected upward. The second insulating layer 132 may cover the extension 248a of the reflective layer 248 extending into the recess h1.

10, the third electrode 247 includes a plurality of end portions 247b extending to the side surface of the semiconductor structure 120 and a plurality of edge electrodes 247-2 connecting the plurality of end portions 247b. .

The rim electrode 247-2 may be continuously disposed along the edge of the semiconductor structure 120. [ Therefore, the current dispersion efficiency can be improved even in the border region. However, the present invention is not limited thereto, and the rim electrode 247-2 may be divided into a plurality of portions.

FIG. 11 is a plan view of a semiconductor device according to another embodiment of the present invention, and FIG. 12 is a cross-sectional view taken along the line B-B of FIG.

Referring to FIG. 11, the semiconductor device may include a plurality of recesses h1 and a plurality of third electrodes 247 in a plan view. Each of the third electrodes 247 may be spaced apart from each other and may be surrounded by a plurality of recesses h1. The third electrode 247 according to the embodiment may be disposed at a position where some recesses h1 are omitted.

The diameter of the third electrode 247 may be larger than the diameter of the recess h1, but is not limited thereto. Illustratively, the diameter of the third electrode 247 may be equal to or less than the diameter of the recess h1. In addition, the third electrode 247 may have a planar shape in a polygonal shape.

12, the second conductive layer 150 and the second electrode 246 are electrically connected at a position where the third electrode 247 is disposed, whereas in a region where the third electrode 247 is not disposed, The second electrode 246 and the third electrode 247 may be insulated by the reflective layer 248. Therefore, the area of the reflective layer 248 increases and the light extraction efficiency can be improved.

FIG. 13 is a cross-sectional view of a semiconductor device according to still another embodiment of the present invention, and FIG. 14 is an enlarged view in a direction B in FIG.

Referring to FIG. 13, a plurality of third electrodes 247 may be disposed between the adjacent first recesses h1 and second recesses h1. That is, one third electrode 247 is not integrally formed between the neighboring first recess h1 and the second recess h1, but a plurality of third electrodes 247 may be disposed . Therefore, the current dispersion efficiency can be further improved.

15 is a graph showing changes in aluminum composition according to the thickness of the semiconductor structure of the present invention.

The second conductive semiconductor layer 127 of the semiconductor device according to the embodiment includes aluminum on the first surface (surface layer) in contact with the second electrode 246. Therefore, it is necessary to have an appropriate aluminum composition change for the formation of the ohmic.

15, the first conductive semiconductor layer 124, the barrier layer 126b, the well layer 126a, the second to the second conductive semiconductor layers 127a, 127b, and 127c Aluminum. Therefore, the first conductivity type semiconductor layer 124, the barrier layer 126b, the well layer 126a, and the second to the second conductivity type semiconductor layers 127a, 127b, and 127c may be AlGaN. However, the present invention is not limited thereto.

The electron blocking layer 129 may have an aluminum composition of 50% to 90%. The barrier layer 129 may have a plurality of first barrier layers 129a having a relatively high aluminum composition and a plurality of second barrier layers 129b having a low aluminum composition alternately. When the aluminum composition of the barrier layer 129 is less than 50%, the height of the energy barrier for blocking electrons may be insufficient, light emitted from the active layer 126 may be absorbed by the barrier layer 129, %, The electrical characteristics of the semiconductor device may deteriorate.

The electron blocking layer 129 may include a 1-1 section and a 1-2 section. The closer to the barrier layer 129, the higher the aluminum composition can be. The aluminum composition of the 1-1 section 129-1 may be 80% to 100%. That is, the 1-1 section 129-1 may be AlGaN or AlN. Or the 1-1 section 129-1 may be a super lattice layer in which AlGaN and AlN are alternately arranged.

The thickness of the 1-1 section 129-1 may be about 0.1 nm to 4 nm. If the thickness of the 1-1 section 129-1 is thinner than 0.1 nm, there may be a problem that the movement of electrons can not be efficiently blocked. Also, if the thickness of the 1-1 section 129-1 is thicker than 4 nm, the efficiency of injecting holes into the active layer may be degraded.

The first-second section 129-2 may include an undoped section. The first-second section 129-2 may prevent the dopant from being dispersed in the active layer 126.

The thickness of the second-conductivity-type semiconductor layer 127b may be greater than 10 nm and less than 200 nm. Illustratively, the thickness of the second-second conductivity type semiconductor layer 127b may be 25 nm. If the thickness of the second-second conductivity type semiconductor layer 127b is smaller than 10 nm, the resistance increases in the horizontal direction, and the current injection efficiency may be lowered. In addition, when the thickness of the second-second conductivity type semiconductor layer 127b is larger than 200 nm, the resistance increases in the vertical direction and the current injection efficiency may be lowered.

The aluminum composition of the second-second conductivity type semiconductor layer 127b may be higher than that of the well layer 126a. The aluminum composition of the well layer 126a to produce ultraviolet light may be about 30% to 50%. If the aluminum composition of the second-conductivity-type semiconductor layer 127b is lower than the aluminum composition of the well layer 126a, the second-second conductivity-type semiconductor layer 127b absorbs light, . However, it is not necessarily limited thereto. Illustratively, the aluminum composition in a section of the second-second conductivity type semiconductor layer 127b may be lower than the aluminum composition of the well layer 126a.

The aluminum composition of the second-conductivity-type semiconductor layer 127b may be greater than 40% and less than 80%. When the aluminum composition of the second conductivity type semiconductor layer 127b is less than 40%, there is a problem of absorbing light. When the aluminum composition is more than 80%, the current injection efficiency is deteriorated. Illustratively, when the aluminum composition of the well layer 126a is 30%, the aluminum composition of the second-second conductivity type semiconductor layer 127b may be 40%.

The aluminum composition of the second-first conductivity type semiconductor layer 127a may be lower than the aluminum composition of the well layer 126a. When the aluminum composition of the second-first conductivity type semiconductor layer 127a is higher than the aluminum composition of the well layer 126a, the resistance between the p-ohmic electrodes becomes high, so that sufficient ohmic can not be obtained and the current injection efficiency deteriorates .

The aluminum composition of the second-first conductivity type semiconductor layer 127a may be greater than 1% and less than 50%. If it is larger than 50%, the ohmic contact with the p-ohmic electrode may not be sufficiently performed. If the composition is less than 1%, the GaN composition is close to the GaN composition and the light is absorbed.

The thickness of the second-first conductivity type semiconductor layer 127a may be 1 nm to 30 nm, or 1 nm to 10 nm. As described above, since the composition of aluminum is low for the ohmic operation, the second-first conductivity type semiconductor layer 127a can absorb ultraviolet light. Therefore, it is advantageous from the viewpoint of light output to control the thickness of the second-first conductivity type semiconductor layer 127a as thin as possible.

However, when the thickness of the second-first conductivity type semiconductor layer 127a is controlled to be 1 nm or less, the second-first conductivity type semiconductor layer 127a May be exposed to the outside of the semiconductor structure 120. In addition, when the thickness is larger than 30 nm, the amount of light absorbed becomes too large, and the light output efficiency may decrease.

The thickness of the second-first conductivity type semiconductor layer 127a may be smaller than the thickness of the second-type conductivity type semiconductor layer 127b. The thickness ratio of the second-second conductivity-type semiconductor layer 127b and the second-first conductivity type semiconductor layer 127a may be 1.5: 1 to 20: 1. If the thickness ratio is smaller than 1.5: 1, the thickness of the second-second conductivity type semiconductor layer 127b becomes too thin, and the current injection efficiency can be reduced. In addition, when the thickness ratio is larger than 20: 1, the thickness of the second-first conductivity type semiconductor layer 127a becomes too thin, and the ohmic reliability may deteriorate.

The aluminum composition of the second-conductivity-type semiconductor layer 127b may become smaller as the distance from the active layer 126 increases. In addition, the aluminum composition of the second-first conductivity type semiconductor layer 127a may decrease as the distance from the active layer 126 increases.

At this time, the aluminum reduction width of the second-first conductivity type semiconductor layer 127a may be larger than the aluminum reduction width of the second-type conductivity type semiconductor layer 127b. That is, the rate of change of the Al composition ratio of the second-first conductivity type semiconductor layer 127a with respect to the thickness direction may be greater than the rate of change of the Al composition ratio of the second-type conductivity type semiconductor layer 127b with respect to the thickness direction.

The second-conductivity-type semiconductor layer 127b is thicker than the second-first conductivity-type semiconductor layer 127a, while the aluminum composition must be higher than that of the well layer 126a, so that the reduction width may be relatively slow. However, since the thickness of the second-first conductivity type semiconductor layer 127a is small and the variation range of the aluminum composition is large, the decrease in the aluminum composition can be relatively large.

The second and third conductivity type semiconductor layers 127c may have a uniform aluminum composition. The thickness of the second and third conductivity type semiconductor layers 127c may be 20 nm to 60 nm. The aluminum composition of the second and third conductivity type semiconductor layers 127c may be 40% to 70%.

16 is a conceptual view of a semiconductor device package according to an embodiment of the present invention.

The semiconductor device is composed of a package and can be used for curing a resin, a resist, SOD or SOG. Alternatively, the semiconductor device may be used for therapeutic medical use or for sterilizing air purifiers, water purifiers, and the like.

16, the semiconductor device package comprises a body 2 formed with a groove 3, a semiconductor element 1 disposed on the body 2, and a semiconductor element 1 disposed on the body 2 and electrically connected to the semiconductor element 1 And may include a pair of lead frames 5a and 5b connected thereto. The semiconductor element 1 may include all of the structures described above.

The body 2 may include a material or a coating layer that reflects ultraviolet light. The body 2 can be formed by laminating a plurality of layers 2a, 2b, 2c, and 2d. The plurality of layers 2a, 2b, 2c, 2d may be the same material or may comprise different materials.

The groove 3 may be formed so as to be wider as it is away from the semiconductor element, and a step 3a may be formed on the inclined surface.

The light-transmitting layer 4 may cover the groove 3. [ The light-transmitting layer 4 may be made of a glass material, but is not limited thereto. The light-transmitting layer 4 is not particularly limited as long as it is a material capable of effectively transmitting ultraviolet light. The inside of the groove 3 may be an empty space.

The semiconductor device may be used as a light source of an illumination system, or as a light source of an image display device or a lighting device. That is, semiconductor devices can be applied to various electronic devices arranged in a case to provide light. Illustratively, when a semiconductor device and an RGB phosphor are mixed and used, white light with excellent color rendering (CRI) can be realized.

The above-described semiconductor device is composed of a light emitting device package and can be used as a light source of an illumination system, for example, as a light source of a video display device or a lighting device.

When used as a backlight unit of a video display device, it can be used as an edge type backlight unit or as a direct-type backlight unit. When used as a light source of a lighting device, it can be used as a regulator or a bulb type. It is possible.

The light emitting element includes a laser diode in addition to the light emitting diode described above.

The laser diode may include the first conductivity type semiconductor layer, the active layer and the second conductivity type semiconductor layer having the above-described structure, like the light emitting element. Then, an electro-luminescence (electroluminescence) phenomenon in which light is emitted when an electric current is applied after bonding the p-type first conductivity type semiconductor and the n-type second conductivity type semiconductor is used, There are differences in the directionality and phase of light. That is, the laser diode can emit light having one specific wavelength (monochromatic beam) with the same phase and in the same direction by using a phenomenon called stimulated emission and a constructive interference phenomenon. It can be used for optical communication, medical equipment and semiconductor processing equipment.

As the light receiving element, a photodetector, which is a kind of transducer that detects light and converts the intensity of the light into an electric signal, is exemplified. As photodetectors, photodetectors (silicon, selenium), photodetectors (cadmium sulfide, cadmium selenide), photodiodes (for example, visible blind spectral regions or PDs with peak wavelengths in the true blind spectral region) A transistor, a photomultiplier tube, a phototube (vacuum, gas-filled), and an IR (Infra-Red) detector, but the embodiment is not limited thereto.

In addition, a semiconductor device such as a photodetector may be fabricated using a direct bandgap semiconductor, which is generally excellent in photo-conversion efficiency. Alternatively, the photodetector has a variety of structures, and the most general structure includes a pinned photodetector using a pn junction, a Schottky photodetector using a Schottky junction, and a metal-semiconductor metal (MSM) photodetector have.

The photodiode, like the light emitting device, may include the first conductivity type semiconductor layer having the structure described above, the active layer, and the second conductivity type semiconductor layer, and may have a pn junction or a pin structure. The photodiode operates by applying reverse bias or zero bias. When light is incident on the photodiode, electrons and holes are generated and a current flows. At this time, the magnitude of the current may be approximately proportional to the intensity of the light incident on the photodiode.

A photovoltaic cell or a solar cell is a type of photodiode that can convert light into current. The solar cell, like the light emitting device, may include the first conductivity type semiconductor layer, the active layer and the second conductivity type semiconductor layer having the above-described structure.

In addition, it can be used as a rectifier of an electronic circuit through a rectifying characteristic of a general diode using a p-n junction, and can be applied to an oscillation circuit or the like by being applied to a microwave circuit.

In addition, the above-described semiconductor element is not necessarily implemented as a semiconductor, and may further include a metal material as the case may be. For example, a semiconductor device such as a light receiving element may be implemented using at least one of Ag, Al, Au, In, Ga, N, Zn, Se, P, or As, Or may be implemented using a doped semiconductor material or an intrinsic semiconductor material.

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

120: Semiconductor structure
124: First conductive type semiconductor layer
126:
127: second conductive type semiconductor layer
142: first electrode
150: second conductive layer
246: second electrode
247: third electrode
248: Reflective layer

Claims (15)

A first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer,
A semiconductor structure including a plurality of recesses penetrating the second conductivity type semiconductor layer and the active layer and disposed to a partial region of the first conductivity type semiconductor layer;
A first electrode disposed inside the plurality of recesses and electrically connected to the first conductive semiconductor layer;
A second electrode disposed on a first surface of the second conductive semiconductor layer;
A third electrode disposed on the second electrode;
A reflective layer disposed on the second electrode and the third electrode;
A first conductive layer electrically connected to the first electrode; And
And a second conductive layer electrically connected to the second electrode through the reflective layer,
The second electrode is a light-transmitting electrode, the third electrode comprises Al,
And the area ratio of the third electrode and the reflective layer is 1: 0.8 to 1: 1.3.
The method according to claim 1,
Wherein the reflective layer comprises a plurality of first reflective layers having a first refractive index and a plurality of second reflective layers having a second refractive index.
3. The method of claim 2,
Wherein the reflective layer comprises a DBR (Distributed Bragg Reflector).
The method of claim 3,
The third electrode includes a plurality of holes,
Wherein the plurality of first electrodes are disposed in a plane within the plurality of holes.
5. The method of claim 4,
Wherein the hole has a polygonal shape or a circular shape.
The method according to claim 1,
Wherein an area ratio of the first surface of the second conductivity type semiconductor layer to the reflective layer is 1: 0.3 to 1: 0.7.
The method according to claim 1,
Wherein the third electrode comprises:
A first layer comprising Al,
A second layer disposed between the first layer and the second electrode, and
And a third layer disposed between the first layer and the second conductive layer,
Wherein the second layer comprises at least one of Cr, Ti, and Ni,
Wherein the third layer comprises at least one of Ni, Ti, No, Pt, W, Au, and Ni.
The method according to claim 1,
Wherein an area of the second electrode is larger than an area of the third electrode.
The method according to claim 1,
Wherein an area ratio of the first surface of the second conductivity type semiconductor layer to the first electrode is 1: 0.08 to 1: 0.15.
The method according to claim 1,
A first insulating layer disposed in the recess to isolate the first conductive layer from the active layer and the second conductive type semiconductor layer,
And a second insulating layer disposed between the first conductive layer and the second conductive layer.
11. The method of claim 10,
Wherein the first insulating layer includes an extension extending to the first surface.
12. The method of claim 11,
Wherein the reflective layer is filled in a spaced-apart region between the extended portion and the second electrode.
The method according to claim 1,
And the third electrode includes a plurality of end portions extending to an edge of the first surface, and a rim electrode connecting the plurality of end portions.
The method according to claim 1,
Wherein the active layer emits light in an ultraviolet wavelength range.
A first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer,
A semiconductor structure including a plurality of recesses penetrating the second conductivity type semiconductor layer and the active layer and disposed to a partial region of the first conductivity type semiconductor layer;
A first electrode disposed inside the plurality of recesses and electrically connected to the first conductive semiconductor layer;
A second electrode disposed on a first surface of the second conductive semiconductor layer;
A third electrode disposed on the second electrode;
A reflective layer disposed on the second electrode and the third electrode;
A first conductive layer electrically connected to the first electrode; And
And a second conductive layer electrically connected to the second electrode through the reflective layer,
The second electrode is a light-transmitting electrode, the third electrode comprises Al,
The third electrode includes a plurality of holes,
Wherein the plurality of first electrodes are disposed in a plane on the inside of the hole.

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