KR20200050763A - Light emitting device - Google Patents

Abstract

According to an embodiment of the present invention, disclosed is a light emitting element with excellent light emitting efficiency. The light emitting element comprises: a light emitting structure including 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 first electrode electrically connected with the first conductivity type semiconductor layer; a second electrode electrically connected with the second conductivity type semiconductor layer; a first conductive layer electrically connected with the first electrode; a second conductive layer electrically connected with the second electrode; and a cover layer disposed between the second electrode and the second conductive layer. The second conductivity type semiconductor layer includes a protrusion unit protruding toward the second conductive layer. A metal coupling layer is formed between the cover layer and the second conductive layer, and is extended to a side surface of the protrusion unit.

Description

Light emitting device {LIGHT EMITTING DEVICE}

The embodiment relates to a light emitting device.

Semiconductor devices including compounds such as GaN and AlGaN have many advantages such as having a wide and easily adjustable band gap energy, and thus can be used in various ways as light emitting devices, light receiving devices, and various diodes.

In particular, light emitting devices such as light emitting diodes or laser diodes using semiconductor group 3 or 2-6 compound semiconductor materials of semiconductors are red, green, and green due to the development of thin film growth technology and device materials. Various colors such as blue and ultraviolet light can be realized, and white light with high efficiency can be realized by using fluorescent materials or combining colors. Compared with conventional light sources such as fluorescent and incandescent lamps, low power consumption, semi-permanent life, and quick response It has the advantages of speed, safety and environmental friendliness.

In addition, when a light-receiving device such as a photodetector or a solar cell is manufactured using a semiconductor group 3 or 2-6 compound semiconductor material of a semiconductor, development of the device material absorbs light in various wavelength ranges to generate a photocurrent. By doing so, it is possible to use light in various wavelength ranges from gamma rays to radio wavelength ranges. In addition, it has the advantages of fast response speed, safety, environmental friendliness, and easy adjustment of device materials, and thus can be easily used in power control or microwave circuits or communication modules.

Therefore, the semiconductor device can replace a light emitting diode backlight, a fluorescent lamp, or an incandescent light bulb that replaces a cold cathode tube (CCFL) constituting a backlight of a transmission module of an optical communication means and a backlight of a liquid crystal display (LCD) display device. Applications are expanding to white light-emitting diode lighting devices, automobile headlights and traffic lights, and sensors that detect gas or fire. In addition, the application of the semiconductor device can be expanded 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, and sterilization by curing or sterilizing.

Recently, research on ultraviolet light-emitting devices has been actively conducted, but there are still problems in that ultraviolet light-emitting devices are difficult to implement in a vertical type, and there is a problem of low light emission efficiency.

The embodiment may provide a light emitting device having excellent light emission efficiency.

In addition, it is possible to provide a light emitting device with a low operating voltage.

The problem to be solved in the embodiment is not limited to this, and it will be said that the object or effect that can be grasped from the solution means or the embodiment of the problem described below is also included.

The light emitting device according to the embodiment may include a light emitting structure including 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 first electrode electrically connected to the first conductivity type semiconductor layer; A second electrode electrically connected to the second conductivity type semiconductor layer; A first conductive layer electrically connected to the first electrode; A second conductive layer electrically connected to the second electrode; And a cover layer disposed between the second electrode and the second conductive layer, wherein the second conductivity type semiconductor layer includes a protrusion projecting toward the second conductive layer, and the cover layer and the second A metal bonding layer is formed between the conductive layers, and the metal bonding layer extends to the side surface of the protrusion.

According to the embodiment, since the second conductivity type semiconductor layer becomes thinner and the UV light absorption rate is lowered, the luminous efficiency can be improved.

In addition, it is possible to lower the operating voltage by preventing the second conductive layer from being oxidized by the second electrode.

Various and beneficial advantages and effects of the present invention are not limited to the above, and will be more easily understood in the course of describing specific embodiments of the present invention.

1 is a conceptual diagram of a light emitting device according to a first embodiment of the present invention,
2 is an enlarged view of part A of FIG. 1,
3 is an enlarged view of part B of FIG. 2,
4A is a plan view of a light emitting device according to a first embodiment of the present invention,
Figure 4b is a partially enlarged view of Figure 4a,
Figure 5 is a modification of Figure 3,
6 is a conceptual diagram of a light emitting device according to a second embodiment of the present invention,
7 is an enlarged view of part C of FIG. 6,
8 is a cross-sectional view taken along line AA of FIG. 7,
9 is a modification of FIG. 8,
10 is a cross-sectional view of a light emitting device according to a third embodiment of the present invention,
11 is a conceptual diagram of a light emitting device package according to an embodiment of the present invention,
12 is a plan view of a light emitting device package according to an embodiment of the present invention.

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

However, the technical spirit of the present invention is not limited to some embodiments described, but may be implemented in various different forms, and within the scope of the technical spirit of the present invention, one or more of its components between embodiments may be selectively selected. It can be used by bonding and substitution.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention, unless specifically defined and specifically described, can be generally understood by those skilled in the art to which the present invention pertains. It can be interpreted as meaning, and commonly used terms, such as predefined terms, may interpret the meaning in consideration of the contextual meaning of the related technology.

In addition, the terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention.

In the present specification, a singular form may also include a plural form unless specifically stated in the phrase, and is combined with A, B, and C when described as "at least one (or more than one) of A and B, C". It can contain one or more of all possible combinations.

In addition, in describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used.

These terms are only for distinguishing the component from other components, and the term is not limited to the nature, order, or order of the component.

And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, the component is not only directly connected to, coupled to, or connected to the other component, but also to the component It may also include the case of 'connected', 'coupled' or 'connected' due to another component between the other components.

Further, when described as being formed or disposed in the "top (top) or bottom (bottom)" of each component, the top (top) or bottom (bottom) is not only when the two components are in direct contact with each other, Also included is the case where one or more other components are formed or disposed between the two components. In addition, when expressed as "up (up) or down (down)", it may include the meaning of the downward direction as well as the upward direction based on one component.

The light emitting structure according to an embodiment of the present invention may output light in the ultraviolet wavelength range. Illustratively, the light emitting structure may output light (UV-A) in the near ultraviolet wavelength range, may output light (UV-B) in the far ultraviolet wavelength range, and may output light (UV-C) in the deep ultraviolet wavelength range. Can print The wavelength range can be determined by the composition ratio of Al in the light emitting structure. In addition, the light emitting structure can output light of various wavelengths having different light intensities, and the peak wavelength of light having the strongest intensity relative to the intensity of other wavelengths among the wavelengths of light that emits light is near-ultraviolet, far-ultraviolet, or deep It can be ultraviolet.

For example, light (UV-A) in the near ultraviolet wavelength band may have a main peak in the range of 320 nm to 420 nm, and light (UV-B) in the far ultraviolet wavelength band may have a main peak in the range of 280 nm to 320 nm, Light (UV-C) of the deep ultraviolet wavelength band may have a main peak in a range of 100 nm to 280 nm. The light emitting structure may generate ultraviolet light having a maximum peak wavelength at a wavelength of 100 nm to 420 nm.

1 is a conceptual diagram of a light emitting device according to a first embodiment of the present invention, FIG. 2 is an enlarged view of part A of FIG. 1, FIG. 3 is an enlarged view of part B of FIG. 2, and FIG. 4A is a first view of the present invention. 4B is a partially enlarged view of FIG. 4A, and FIG. 5 is a modified example of FIG. 3.

1 and 2, a light emitting device according to an embodiment includes a conductive substrate 170, a first conductivity type semiconductor layer 124, a second conductivity type semiconductor layer 127, and an active layer 126 It may include a light emitting structure 120, a first electrode 142 electrically connected to the first conductivity type semiconductor layer 124, and a second electrode 146 electrically connected to the second conductivity type semiconductor layer 127. Can be.

The first conductivity-type semiconductor layer 124 may be formed of a compound semiconductor such as a III-V group or a II-VI group, and the first dopant may be doped. The first conductivity type semiconductor layer 124 is a semiconductor material having a composition formula of In _x1 Al _y1 Ga _{1 -x1 -y1} N (0≤x1≤1, 0≤y1≤1, 0≤x1 + y1≤1), for example For example, it may be selected from AlGaN, InGaN, InAlGaN, and the like. Further, 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 conductive semiconductor layer 124 doped with the first dopant may be an n-type semiconductor layer.

The active layer 126 may be disposed between the first conductivity type semiconductor layer 124 and the second conductivity type semiconductor layer 127. The active layer 126 may be a layer in which electrons (or holes) injected through the first conductivity type semiconductor layer 124 and holes (or electrons) injected through the second conductivity type semiconductor layer 127 are recombined.

The active layer 126 may generate light having a wavelength corresponding to the bandgap energy of the well layer to be described later included in the active layer 126, as the electrons and holes recombine and the electrons transition to a low energy level. The wavelength of light having a relatively greatest intensity among the wavelengths of light emitted by the light emitting device may be ultraviolet rays, and the ultraviolet rays may be the above-mentioned near ultraviolet rays, far ultraviolet rays, or deep ultraviolet rays.

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

The second conductivity-type semiconductor layer 127 is formed on the active layer 126, and may be formed of a compound semiconductor such as a III-V group or a II-VI group, and is second to the second conductivity-type semiconductor layer 127. The dopant can be doped. The second conductive semiconductor layer 127 is a semiconductor material or AlGaN having a composition formula of In _x5 Al _y2 Ga _{1 -x5- y2} N (0≤x5≤1, 0≤y2≤1, 0≤x5 + y2≤1) , AlInN, AlGaAs, GaP, GaAs, GaAsP, 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.

An electron blocking layer (not shown) may be disposed between the active layer 126 and the second conductivity-type semiconductor layer 127. The electron blocking layer (not shown) does not emit electrons supplied from the first conductivity type semiconductor layer 124 to the active layer 126 by recombination in the active layer 126, and the second conductivity type semiconductor layer 127 ) To block the flow exiting, thereby increasing the probability of recombination of electrons and holes in the active layer 126. The energy band gap of the electron blocking layer (not shown) may be larger than the energy band gap of the active layer 126 and / or the second conductivity type semiconductor layer 127.

The first conductivity type semiconductor layer 124, the active layer 126, and the second conductivity type semiconductor layer 127 may all include aluminum (Al). Accordingly, the compositions of the first conductivity type semiconductor layer 124, the active layer 126, and the second conductivity type semiconductor layer 127 may all be AlGaN. However, the composition of the semiconductor layer is not necessarily limited thereto, and may be appropriately adjusted according to the output wavelength.

The light emitting structure 120 may include a second conductive semiconductor layer 127, an active layer 126, and a recess 128 penetrating to a portion of the first conductive semiconductor layer 124. In the case where the light emitting structure 120 generates ultraviolet light, current distribution characteristics of the light emitting structure 120 may be deteriorated because it has high bandgap energy. Therefore, even if the light emitting area is sacrificed, the plurality of recesses 128 may be formed to increase the light output by arranging more of the first electrode 142.

The second conductivity-type semiconductor layer 127 may include a plurality of protrusions 127a protruding toward the conductive substrate 170 and a flat portion 127b disposed between the plurality of protrusions 127a. The configuration of the flat portion 127b may be a region other than the region where the protrusion 127a is formed. According to the embodiment, the flat portion 127b is formed to be relatively thin to reduce the absorption rate of ultraviolet light.

The second conductive semiconductor layer 127 may have a relatively low aluminum composition in order to lower the contact resistance with the second electrode 146. As a result, the second conductivity type semiconductor layer 127 can partially absorb ultraviolet light. Therefore, it is preferable to reduce the ultraviolet light absorption rate by making the thickness of the flat portion 127b that the second electrode 146 does not contact thin.

The aluminum composition may be relatively lower in the protrusion 127a in contact with the second electrode 146. The flat portion 127b may be manufactured by growing a portion of the second conductive semiconductor layer 127 as a whole and then etching a portion. As a result, the aluminum composition of the lower surface 127b-1 of the flat portion 127b may be higher than the aluminum composition of the lower surface 127a-1 of the protruding portion 127a.

The first electrode 142 is disposed inside the recess 128 and can be electrically connected to the first conductive semiconductor layer 124. Further, the second electrode 146 may be disposed on the lower surface of the second conductivity-type semiconductor layer 127 to be electrically connected.

The first electrode 142 and the second electrode 146 may be ohmic electrodes. The first electrode 142 and the second electrode 146 are indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IZAO), indium gallium zinc oxide (IGZO) ), Indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IZON (IZO Nitride), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), ZnO, IrOx, RuOx, NiO, RuOx / ITO, Ni / IrOx / Au, or Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, It may be formed of at least one of Ru, Mg, Zn, Pt, Au, Hf, but is not limited to these materials. For example, the first electrode 142 may have a plurality of metal layers (eg, Cr / Al / Ni), and the second electrode 146 may be ITO.

The second conductive layer 150 may be electrically connected to the second electrode 146 and the bonding pad 166. Accordingly, the bonding pad 166, the second conductive layer 150, and the second electrode 146 may form one electrical channel.

The second conductive layer 150 is made of a material having good adhesion with the first insulating layer 131, and is made of at least one material selected from the group consisting of materials such as Cr, Ti, Ni, Au, and alloys thereof. It may be made of a single layer or a plurality of layers.

The cover layer 147 may be disposed between the second electrode 146 and the second conductive layer 150. The cover layer 147 may prevent the second conductive layer 150 from being oxidized by oxygen diffused from the second electrode 146. The cover layer 147 may include Cr, Ni, Au, Ti, etc., but is not limited thereto. For example, the cover layer 147 may include a Cr / Ni / Au / Ti layer.

The second insulating layer 132 may electrically insulate the first conductive layer 165 from the second conductive layer 150. The first insulating layer 131 and the second insulating layer 132 may be made of the same material as each other, or may be made of different materials.

The first conductive layer 165 may include a plurality of protruding electrodes 165a that penetrate through the recess 128 and the second insulating layer 132 and are electrically connected to the plurality of first electrodes 142. Accordingly, the first conductive layer 165 and the plurality of first electrodes 142 may be defined as first channel electrodes.

The first conductive layer 165 may be made of a material having excellent reflectance. For example, the first conductive layer 165 may include metal such as Ti, Ni, and Al. For example, when the first conductive layer 165 includes aluminum, ultraviolet light emitted from the active layer 126 may be reflected upward.

The bonding layer 160 may be disposed along the shape of the bottom surface of the light emitting structure 120 and the recess 128. The bonding layer 160 may include a conductive material. For example, the bonding layer 160 may include a material selected from the group consisting of gold, tin, indium, aluminum, silicon, silver, nickel, and copper, or alloys thereof.

The conductive substrate 170 may include a metal or semiconductor material. The conductive substrate 170 may be a metal having excellent electrical conductivity and / or thermal conductivity. In this case, heat generated during operation of the light emitting device can be quickly discharged to the outside. In addition, the first electrode 142 may be supplied with a current from the outside through the conductive substrate 170.

The conductive substrate 170 may include a material selected from the group consisting of silicon, molybdenum, silicon, tungsten, copper, and aluminum or alloys thereof.

The passivation layer 180 may be disposed on the top and side surfaces of the light emitting structure 120. The passivation layer 180 may have a thickness of 200 nm or more and 500 nm or less. In the case of 200 nm or more, the device can be protected from external moisture or foreign matter to improve the electrical and optical reliability of the device, and in the case of 500 nm or less, stress applied to the light emitting device can be reduced, and the optical and electrical reliability of the light emitting device As this decreases or the process time of the light emitting device increases, a problem that the unit price of the light emitting device increases is improved.

Unevenness may be formed on the top surface of the light emitting structure 120. Such irregularities may improve the extraction efficiency of light emitted from the light emitting structure 120. The unevenness may have a different average height depending on the ultraviolet wavelength, and in the case of UV-C, the light extraction efficiency may be improved when it has a height of about 300 nm to 800 nm and an average of about 500 nm to 600 nm.

Referring to FIG. 3, a metal bonding layer 148 may be formed between the cover layer 147 and the second conductive layer 150. The metal bonding layer 148 may be formed by diffusion at an interface in the process of forming the second conductive layer 150 on the cover layer 147. The adhesion between the cover layer 147 and the second conductive layer 150 may be improved by the metal bonding layer 148. Therefore, reliability can be improved. At this time, the metal bonding layer 148 may extend to the side surface 127a-2 of the protrusion 127a. The metal bonding layer 148 formed before the LLO process may be diffused into all regions between the cover layer 147 and the second conductive layer 150. Therefore, some may spread toward the epi. Therefore, the metal bonding layer 148 may be formed on the side surface 127a-2 of the protrusion 127a. Also, in some cases, the metal bonding layer 148 may extend to the lower surface 127b-1 of the flat portion 127b.

The metal bonding layer 148 may include the composition of the cover layer 147 and the composition of the second conductive layer 150. Exemplarily, the metal bonding layer 148 may have a composition of Cr, Ni, and Al, but is not limited thereto.

The thickness T2 of the protrusion 127a may be thicker than the thickness T1 of the flat portion 127b. This is because the flat portion 127b is preferably formed thin to lower the absorption rate of ultraviolet light, and the protrusion 127a is preferably formed relatively thick to lower the contact resistance with the second electrode 146. Since the second conductive semiconductor layer 127 is designed to have a lower aluminum composition as it approaches the second electrode 146, the lower surface 127a-1 of the protrusion 127a is aluminum among the second conductive semiconductor layers 127. The composition may be the lowest. If necessary, the lower surface of the protrusion 127a may be formed of a GaN layer to improve ohmic performance.

The ratio (T2: T1) of the thickness of the protrusion 127a and the thickness of the flat portion 127b may be 1: 0.16 to 1: 0.75. When the ratio of the thickness is less than 1: 0.16 (Example 1: 0.05), the thickness of the flat portion 127b becomes too thin, and the active layer 126 may be damaged during the etching process. In addition, when the thickness of the protruding portion 127a is greater than 1: 0.75, the thickness of the flat portion 127b becomes thick, so that the amount of light absorption increases, so that the luminous efficiency may be lowered. For example, the thickness of the protruding portion 127a may be 40 μm to 60 μm, and the thickness of the flat portion may be 10 μm to 30 μm.

4A and 4B, the second electrode 146 may include a plurality of closed loops 146-1 extending in a line shape and surrounding the plurality of recesses 128, respectively. The plurality of closed loops 146-1 may be connected to each other, but are not limited thereto, and may be disposed apart from each other. The plurality of recesses 128 may be disposed at the centers of the plurality of closed loops 146-1, respectively.

The plurality of closed loops 146-1 may include a plurality of linear electrodes 146a disposed between neighboring recesses 128, respectively. The plurality of linear electrodes 146a may have a constant width W1 in the longitudinal direction. The width W1 of the linear electrode 146a may be 2 μm to 10 μm, but is not limited thereto. According to this configuration, the area of the second electrode 146 disposed between the adjacent recesses 128 becomes constant, so that the current dispersion efficiency can be improved.

The closed loop 146-1 may be defined as a region having an independent space by a plurality of linear electrodes 146a. That is, all of the linear electrodes 146a constituting the plurality of closed loops 146-1 may be connected, but only six linear electrodes 146a forming an independent space are defined as one closed loop 146-1. can do.

Any one of the plurality of recesses 128 may be surrounded by the plurality of recesses 128. In this case, the line Y1 connecting the centers of the closest recesses 128 surrounding one of the recesses 128 may have a polygonal shape.

For example, the plurality of recesses 128 may include six adjacent recesses 128 surrounding one recess 128. Accordingly, the plurality of linear electrodes 146a may be arranged in a hexagonal shape along six adjacent recesses 128.

However, the shape of the closed loop 146-1 is not necessarily limited thereto, and may be implemented in various polygonal shapes such as a square shape or an octagonal shape. That is, the shape of the closed loop 146-1 may be deformed according to the number and location of the recesses 128.

The area ratio between the first electrode 142 and the second electrode 146 may be 1: 1.28 to 1: 1.68. When the area ratio is smaller than 1: 1.28, the area of the second electrode 146 is reduced, so it may be difficult to uniformly inject current into the second conductivity type semiconductor layer. In addition, when the area ratio is greater than 1: 1.68, the area of the first electrode 142 is relatively reduced, so that the dispersion efficiency of the current injected into the first conductivity type semiconductor layer 124 may be reduced. That is, since the area of the first electrode 142 and the area of the second electrode 146 are in a trade-off relationship with each other, it is necessary to appropriately adjust the light emission efficiency.

The cover layer 147 may be disposed to surround the second electrode 146. Therefore, the cover layer 147 may be disposed to extend between the plurality of recesses 128 in a plane, and surround the plurality of recesses 128, respectively. The width W2 of the cover layer may be greater than the width W1 of the linear electrode 146a.

The protrusions 127a may extend between a plurality of recesses 128 in a plane to surround the plurality of recesses 128, respectively. The shape of the protrusion 127a may have a polygonal shape corresponding to the shape of the second electrode 146. That is, the protrusion 127a may have a plurality of closed loops surrounding the recess. The width W3 of the protrusion 127a may be greater than the width W1 of the linear electrode 146a. The second electrode 146 and the cover layer 147 may be disposed on the protrusion 127a.

The ratio of the area of the protruding portion 127a and the flat portion 127b may be 1: 2.7 to 1: 4.7. That is, the area of the protruding portion 127a may be smaller than the area of the flat portion 127b. When the area ratio is smaller than 1: 2.7 (for example, 1: 2.1), the area of the protruding portion 127a increases, and thus the absorption amount of ultraviolet light increases, so that the luminous efficiency may be lowered. In addition, when the area ratio is greater than 1: 4.7, the area of the protrusion 127a is reduced, so that the area of the second electrode 146 may be reduced. Therefore, the current injection efficiency is lowered and the luminous efficiency may be lowered.

Referring to FIG. 5, the first electrode 142 includes at least one of Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, Ru, Mg, Zn, Pt, Au, Hf Can be formed. In this case, since the first electrode 142 and the cover layer are formed of the same material, one electrode can be formed. For example, the first electrode 142 may be formed of a Cr / Ni.Au / Ti layer. According to this configuration, there is an advantage of maintaining a low operating voltage even after heat treatment. At this time, a metal bonding layer 148 may be formed between the first electrode 142 and the second conductive layer 150.

6 is a conceptual view of a light emitting device according to a second embodiment of the present invention, FIG. 7 is an enlarged view of part C of FIG. 6, FIG. 8 is a cross-sectional view taken along line A-A of FIG. 7, and FIG. 9 is a modification of FIG.

6 and 7, a light emitting device according to an embodiment includes a first conductivity type semiconductor layer 124, a second conductivity type semiconductor layer 127, and a first conductivity type semiconductor layer 124 and a second conductivity A plurality of second conductive semiconductor layers 127, the active layer 126, and a portion of the first conductive semiconductor layer 124 including the active layer 126 disposed between the type semiconductor layers 127 The light emitting structure 120 including the recess 128, the plurality of first electrodes 142 disposed in the plurality of recesses 128 and electrically connected to the first conductive semiconductor layer 124, and the second It includes a plurality of second electrodes 146a electrically connected to the conductive semiconductor layer 127.

The second electrode 146a may be smaller than the diameter of the first electrode 142. For example, the diameter of the first electrode 142 is about 20 μm to 40 μm, while the diameter of the second electrode 146a may be 5 μm to 15 μm.

The diameter ratio of the first electrode 142 and the second electrode 146a may be 1: 0.12 to 1: 0.75. When the diameter ratio is smaller than 1: 0.12 (for example, 1: 0.08), the diameter of the second electrode 146a becomes small, so that the current injection efficiency injected into the second conductivity type semiconductor layer 127 may be lowered. In addition, when the diameter ratio is greater than 1: 0.75, the diameter of the second electrode 146a becomes large, so that it is difficult to arrange a large number of second electrodes 146, and thus the current injection efficiency may be lowered.

The area ratio between the first electrode 142 and the second electrode 146a may be 1: 1.1 to 1: 1.4. When the area ratio is smaller than 1: 1.1 (for example, 1: 1.05), the area of the second electrode 146a becomes small, so that the current efficiency injected into the second conductivity type semiconductor layer 127 may be lowered. In addition, when the area ratio is greater than 1: 1.4, the area of the first electrode 142 becomes small, so that the current injection efficiency may be lowered.

At this time, each second electrode 146a may be surrounded by a cover layer 147a. Therefore, a part of the cover layer 147a may contact the lower surface 127a-1 of the protrusion 127a.

Referring to FIG. 8, a plurality of second electrodes 146a may be disposed on the lower surface 127a-1 of the protrusion 127a. Also, each cover layer 147a may be disposed to surround the second electrode 146a.

A metal bonding layer 148 may be formed between the plurality of cover layers 147a and the second conductive layer 150. At this time, the metal bonding layer 148 may extend from the side of the cover layer 147a and extend to the side of the protrusion 127a. Further, the metal bonding layer 148 may extend to the lower surface 127a-1 of the protrusion 127a between the adjacent cover layers 147a.

10 is a cross-sectional view of a light emitting device according to a third embodiment of the present invention.

Referring to FIG. 10, the light emitting device according to the embodiment includes a transparent substrate 110, a light emitting structure 120 disposed on the substrate, and a first electrode 142 electrically connected to the first conductive semiconductor layer 124. , A second electrode 146 electrically connected to the second conductive semiconductor layer 127, a cover layer 147 disposed on the second electrode, and a conductive layer 150 disposed on the cover layer. have.

The transparent substrate 110 may be formed of a material selected from sapphire (Al ₂ O ₃ ), SiC, GaAs, GaN, ZnO, Si, GaP, InP, and Ge, but is not limited thereto. The substrate 110 may transmit light in an ultraviolet wavelength band.

The buffer layer (not shown) may mitigate lattice mismatch between the transparent substrate 110 and the semiconductor layers. The buffer layer may be a combination of group III and group V elements, or may include any one of AlN, AlGaN, InAlGaN, and AlInN. In this embodiment, the buffer layer may be AlN, but is not limited thereto. The buffer layer may include a dopant, but is not limited thereto.

The structures of the first conductivity type semiconductor layer 124, the active layer 126, and the second conductivity type semiconductor layer 127 may be the same as described above. The second conductivity-type semiconductor layer 127 may include a protrusion 127a protruding in a direction opposite to the conductive substrate 170 and a flat portion 127b disposed around the protrusion 127a. The configuration of the flat portion 127b may be a region other than the region where the protrusion 127a is formed. According to the embodiment, the flat portion 127b is formed to be relatively thin to reduce the absorption rate of ultraviolet light.

The second conductive semiconductor layer 127 may have a relatively low aluminum composition in order to lower the contact resistance with the second electrode 146. As a result, the second conductivity type semiconductor layer 127 can partially absorb ultraviolet light. Therefore, it is preferable to reduce the ultraviolet light absorption rate by making the thickness of the flat portion 127b that the second electrode 146 does not contact thin.

The aluminum composition may be relatively lower in the protrusion 127a in contact with the second electrode 146. The flat portion 127b may be manufactured by growing a portion of the second conductive semiconductor layer 127 as a whole and then etching a portion. As a result, the aluminum composition of the flat portion 127b may be higher than that of the protrusion 127a.

The first electrode 142 may be electrically connected to the first conductivity type semiconductor layer 124. Also, the second electrode 146 may be electrically connected to the protrusion 127a.

The first electrode 142 and the second electrode 146 may be ohmic electrodes. The first electrode 142 and the second electrode 146 are indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IZAO), indium gallium zinc oxide (IGZO) ), Indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IZON (IZO Nitride), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), ZnO, IrOx, RuOx, NiO, RuOx / ITO, Ni / IrOx / Au, or Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, It may be formed of at least one of Ru, Mg, Zn, Pt, Au, Hf, but is not limited to these materials. For example, the first electrode 142 may have a plurality of metal layers (eg, Cr / Al / Ni), and the second electrode 146 may be ITO.

The conductive layer 150 may be electrically connected to the second electrode 146. The conductive layer 150 is made of a material having good adhesion with the first insulating layer 131, and may be made of at least one material selected from the group consisting of materials such as Cr, Ti, Ni, Au, and alloys thereof. And may consist of a single layer or multiple layers.

The cover layer 147 may be disposed between the second electrode 146 and the conductive layer 150. The cover layer 147 may prevent the conductive layer 150 from being oxidized by oxygen diffused from the second electrode 146. The cover layer 147 may include Cr, Ni, Au, Ti, etc., but is not limited thereto. For example, the cover layer 147 may include a Cr / Ni / Au / Ti layer.

A metal bonding layer 148 may be formed between the cover layer 147 and the conductive layer 150. The metal bonding layer 148 may be formed by diffusion at an interface in the process of forming the conductive layer 150 on the cover layer 147. At this time, the metal bonding layer 148 may extend to the side of the protrusion 127a.

The metal bonding layer 148 may include the composition of the cover layer 147 and the composition of the conductive layer 150. Exemplarily, the metal bonding layer 148 may have a composition of Cr, Ni, and Al, but is not limited thereto.

The first insulating layer 131 may be disposed between the first electrode 142 and the second electrode 146, and the second insulating layer 132 may include a conductive layer 150, a first insulating layer 131, and It may be disposed on the first electrode 142.

The first pad 171 penetrates the second insulating layer 132 and is electrically connected to the first electrode 142, and the second pad 172 penetrates the second insulating layer 132 to pass the conductive layer 150 ).

11 is a conceptual diagram of a light emitting device package according to an embodiment of the present invention, and FIG. 12 is a plan view of the light emitting device package according to an embodiment of the present invention.

11 and 12, the light emitting device package is a light emitting device 10 disposed on a body 2 having a groove 3, a light emitting device 10 disposed on the body 2, and a body 2 It may include a pair of lead frames (5a, 5b) that are electrically connected to. The light emitting device 10 may include all of the above-described configurations.

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

The groove 3 may be formed to be wider as it is farther from the light emitting device 10, and a step 3a may be formed on the inclined surface.

The light emitting device 10 is disposed on the first lead frame 5a and may be connected to the second lead frame 5b by a wire. At this time, the first lead frame 5a and the second lead frame 5b may be arranged to surround the side surfaces of the light emitting device 10.

The light-transmitting layer 4 may cover the groove 3. The light-transmitting layer 4 is made of glass, but is not necessarily 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 interior of the groove 3 may be an empty space.

The light emitting device can be applied to various types of light source devices. Illustratively, the light source device may be a concept including a sterilizing device, a curing device, a lighting device, and a display device and a vehicle lamp. That is, the light emitting device can be applied to various electronic devices that are disposed in a case and provide light.

The sterilizing device may include a light emitting device according to an embodiment to sterilize a desired area. The sterilization device may be applied to household appliances such as water purifiers, air conditioners, and refrigerators, but is not limited thereto. That is, the sterilization device can be applied to all of various products (eg, medical devices) that require sterilization.

Illustratively, the water purifier may include a sterilizing device according to an embodiment to sterilize circulating water. The sterilizing device may be disposed on a nozzle or discharge port through which water circulates to irradiate ultraviolet rays. At this time, the sterilization device may include a waterproof structure.

The curing device may be equipped with a light emitting device according to an embodiment to cure various types of liquids. The liquid may be a concept including all of various materials that are cured when irradiated with ultraviolet rays. Illustratively, a curing device can cure various types of resins. Alternatively, the curing device may be applied to cure beauty products such as nail polish.

The lighting device may include a light source module including a substrate and a light emitting device of the embodiment, a heat dissipation unit that emits heat from the light source module, and a power supply unit that processes or converts an electrical signal received from the outside and provides the light source module. Further, the lighting device may include a lamp, a head lamp, or a street light.

The display device may include a bottom cover, a reflector, a light emitting module, a light guide plate, an optical sheet, a display panel, an image signal output circuit, and a color filter. The bottom cover, the reflector, the light emitting module, the light guide plate, and the optical sheet may constitute a backlight unit.

The reflector is disposed on the bottom cover, and the light emitting module can emit light. The light guide plate is disposed in front of the reflector to guide the light emitted from the light emitting module to the front, and the optical sheet may include a prism sheet or the like to be disposed in front of the light guide plate. The display panel is disposed in front of the optical sheet, an image signal output circuit supplies an image signal to the display panel, and a color filter can be disposed in front of the display panel.

The embodiments have been mainly described above, but this is merely an example and does not limit the present invention, and those skilled in the art to which the present invention pertains are not exemplified above in the range that does not depart from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be implemented by modification. And differences related to these modifications and applications should be construed as being included in the scope of the invention defined in the appended claims.

Claims (15)

A light emitting structure including 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 first electrode electrically connected to the first conductivity type semiconductor layer;
A second electrode electrically connected to the second conductivity type semiconductor layer;
A first conductive layer electrically connected to the first electrode;
A second conductive layer electrically connected to the second electrode; And
And a cover layer disposed between the second electrode and the second conductive layer,
The second conductivity type semiconductor layer includes a protrusion projecting toward the second conductive layer,
A metal bonding layer is formed between the cover layer and the second conductive layer,
The metal coupling layer is a light emitting device extending to the side of the protrusion.
According to claim 1,
The protrusions are spaced apart from each other and arranged in plural,
The second conductivity-type semiconductor layer includes a flat portion disposed between the plurality of protrusions,
The thickness of the protrusion is a light emitting device thicker than the thickness of the flat portion.
According to claim 2,
The thickness ratio of the protrusion and the flat portion is 1: 0.16 to 1: 0.75.
According to claim 2,
An area ratio of the protrusion and the flat portion is 1: 2.7 to 1: 4.7.
According to claim 1,
The metal bonding layer is a light emitting device comprising aluminum.
According to claim 2,
The metal coupling layer is a light emitting device extending to the lower surface of the flat portion.
According to claim 1,
The second electrode includes ITO,
The cover layer is a light emitting device comprising at least one of Cr, Ni, Au, Ti.
According to claim 1,
The second electrode and the cover layer include at least one of Cr, Ni, Au, and Ti.
According to claim 1,
The light emitting structure includes a recess formed up to a portion of the second conductivity type semiconductor layer, the active layer and the first conductivity type semiconductor layer,
The first electrode is disposed inside the recess and electrically connected to the first conductive semiconductor layer.
The method of claim 9,
The second electrode is a light emitting device that is disposed in plurality on the lower surface of the protrusion.
The method of claim 10,
The cover layer is a light emitting device surrounding each of the plurality of second electrodes.
The method of claim 10,
The second electrode has a diameter smaller than that of the first electrode.
The method of claim 9,
The protrusion is a light emitting device surrounding the plurality of recesses, respectively.
According to claim 1,
The active layer is a light emitting device that generates light having a main peak at 100nm to 320nm.
Body; And
It includes a light emitting device disposed on the body,
The light emitting element,
A light emitting structure including 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 first electrode electrically connected to the first conductivity type semiconductor layer;
A second electrode electrically connected to the second conductivity type semiconductor layer;
A first conductive layer electrically connected to the first electrode;
A second conductive layer electrically connected to the second electrode; And
And a cover layer disposed between the second electrode and the second conductive layer,
The second conductivity type semiconductor layer includes a protrusion projecting toward the second conductive layer,
A metal bonding layer is formed between the cover layer and the second conductive layer,
The metal coupling layer is a light emitting device package extending to the side of the protrusion.

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