KR20170022671A - Light emittng device - Google Patents

Abstract

According to an embodiment, the present invention relates to a light emitting device, which comprises: a light emitting structure including a first conductive semiconductor layer, an active layer disposed on the first conductive semiconductor layer, and a second conductive semiconductor layer disposed on the active layer, and etching the active layer and to a part of the first conductive semiconductor layer from the second conductive semiconductor layer to expose the first conductive semiconductor layer; a plurality of electrodes which are arranged on an area to which the first conductive semiconductor layer is exposed; a plurality of branch electrodes which connect the plurality of electrodes in a horizontal direction; and a second electrode which is arranged on the second conductive semiconductor layer.

Description

[0001] LIGHT EMITTING DEVICE [0002]

An embodiment relates to a light emitting element.

GaN, and AlGaN are widely used for optoelectronics and electronic devices due to their advantages such as wide and easy bandgap energy.

Particularly, a light emitting device such as a light emitting diode (Ligit Emitting Diode) or a laser diode using a semiconductor material of a 3-5 group or a 2-6 group compound semiconductor has been widely used in various fields such as red, green, blue and ultraviolet It can realize various colors, and it can realize efficient white light by using fluorescent material or color combination. It has low power consumption, semi-permanent lifetime, fast response speed, safety, and environment compared to conventional light sources such as fluorescent lamps and incandescent lamps Affinity.

Therefore, a transmission module of the 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, a white light emitting element capable of replacing a fluorescent lamp or an incandescent lamp Diode lighting devices, automobile headlights, and traffic lights. In recent years, light emitting devices emitting light in the ultraviolet wavelength range have been used in various sterilizing devices.

1A is a view showing a conventional light emitting device.

The conventional light emitting device 100 includes the light emitting structure 120 including the first conductive semiconductor layer 122, the active layer 124, and the second conductive semiconductor layer 126, The first electrode 162 may be disposed on the second electrode 150 and the first electrode 162 may be disposed on the first conductive type semiconductor layer 122.

Although not shown, a passivation layer 190 may be disposed on the side and top surfaces of the light emitting structure 120.

In the light emitting device 100, electrons injected through the first conductive type semiconductor layer 122 and holes injected through the second conductive type semiconductor layer 126 meet to form an energy band inherent to the active layer 124 And emits light having energy determined by the light intensity. The light emitted from the active layer 124 may vary depending on the composition of the material forming the active layer 124.

FIG. 1B is a view showing the electrode arrangement of the light emitting device of FIG. 1A.

1B, the first electrode 162 is disposed on the first conductive type semiconductor layer 122 exposed by mesa etching, and the second electrode 166 is disposed on the surface of the second conductive type semiconductor layer 126. When electrons emitted from the first electrode 162 and holes emitted from the second electrode 166 are combined in the active layer 124, electrons and holes in the active layer 124 corresponding to the second electrode 166 This can be mainly combined.

FIG. 1C is a view showing an emission shape of the light emitting device of FIG. 1A.

In FIG. 1C, a region indicated by yellow is a region in which electrons and holes are combined to emit light in the active layer, and a region inside yellow is a region in which light is blocked in the second electrode. 1C shows a case where the second electrode is arranged in a circle, and light emission is concentrated in a region corresponding to the second electrode.

The embodiment attempts to uniformly combine electrons and holes in the entire region of the active layer of the light emitting device.

The embodiment includes a first conductive type semiconductor layer, an active layer on the first conductive type semiconductor layer, and a second conductive type semiconductor layer on the active layer, and the active layer and the first conductive type semiconductor layer Type semiconductor layer, and the first conductivity type semiconductor layer is exposed to a portion of the first conductivity type semiconductor layer; A plurality of electrodes disposed on the exposed region of the first conductivity type semiconductor layer; A plurality of branched electrodes connecting the plurality of electrodes in a horizontal direction; And a second electrode disposed on the second conductive type semiconductor layer.

And an insulating layer electrically isolating the first electrode from the second conductive type semiconductor layer.

The pitch of the branch electrodes may be between 40 micrometers and 800 micrometers.

The first conductive semiconductor layer and the second conductive semiconductor layer may include AlGaN.

And a conductive layer disposed under the second conductive type semiconductor layer.

The conductive layer may comprise GaN.

GaN may be doped with the second conductivity type dopant.

The plurality of branched electrodes may be arranged in a mesh shape.

The second electrode may be disposed in a first region of at least one corner of the light emitting structure.

The plurality of first electrodes may be disposed in a second region of the light emitting structure.

In the light emitting device according to the embodiments, the first electrode is disposed as the base layer and the contact electrode, the branch electrode extends from the contact electrode in the first conductivity type semiconductor layer, So that electrons and holes are combined in the entire region of the active layer to emit light.

1A is a view showing a conventional light emitting device,
FIG. 1B is a view showing the electrode arrangement of the light emitting device of FIG. 1A,
FIG. 1C is a view showing an emission shape of the light emitting device of FIG. 1A,
2 is a view showing an embodiment of a light emitting device,
3 is a sectional view in the direction II 'of FIG. 2,
4 is a view illustrating an embodiment of a light emitting device package in which a light emitting device is disposed.
5 is a view showing an embodiment of a sterilizing apparatus in which a light emitting element is disposed.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

In the description of the embodiment according to the present invention, in the case of being described as being formed "on or under" of each 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. In addition, when expressed by upper or lower (on or under), it is possible to include not only the upward direction but also the downward direction based on one element.

2 is a view showing an embodiment of a light emitting device.

The light emitting device 200 according to the present embodiment includes a bonding layer 256, a channel layer 270, a reflective layer 254 and an ohmic layer 252 disposed on a support substrate 258, The light emitting structure 220 may be disposed.

The support substrate 258 may be implemented as at least one of copper (Cu), gold (Au), nickel (Ni), molybdenum (Mo), and copper-tungsten (Cu-W) The supporting substrate 380 may be a carrier wafer, for example, Si, Ge, GaAs, ZnO, SiC, SiGe, Ga ₂ O ₃ , GaN, or the like.

A bonding layer 256 may be disposed on the supporting substrate 258. The bonding layer 256 can bond the reflective layer 254 to the supporting substrate 258. The bonding layer 256 may include at least one of, for example, Ti, Au, Sn, Ni, Cr, Ga, In, Bi, Cu, Ag or Ta.

A channel layer 270 may be disposed on the bonding layer 270. The channel layer 270 may be formed of a light transmitting material and may be formed of, for example, a metal oxide, a metal nitride, a transparent nitride, a transparent oxide, or a light-transmitting insulating layer. For example, the channel layer 370 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), IZO nitride, IZTO (indium zinc oxide), indium aluminum zinc oxide (IAZO) zinc oxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), SiO 2, SiO x, SiO x N y, Si 3 N 4, Al ₂ O ₃ , TiO _2, and the like.

The channel layer 270 has a groove formed thereon and a reflection layer 254 and an ohmic layer 252 are disposed in the groove so that the channel layer 270 is formed on the ohmic layer 252 on the bonding layer 256. [ And the reflective layer 254.

The reflective layer 254 may be formed of a material having excellent reflection characteristics such as Ag, Ni, Al, Ru, Pd, Ir, Ru, IZO, IZO, IGZO, IGTO, IGZO, IGZO, IGZO, IGZO, IGZO, AZO, ATO, or the like. Also, the reflective layer 260 may be laminated with IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag /

The ohmic layer 252 may be disposed on the reflective layer 254. The ohmic layer 252 may include at least 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 gallium tin oxide, AZO, ATO, GZO, IZON, AGZO, IGZO, ZnO, IrOx, RuOx, NiO, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, Ru, , Au, and Hf, and is not limited to such a material.

A first electrode 262 may be disposed on the ohmic layer 252 and the first electrode 262 may include a base electrode 262a and a contact electrode 262b protruding from the base layer 262a. The contact electrode 262b may be in contact with the first conductivity type semiconductor layer 222 through the second conductivity type semiconductor layer 226 and the active layer 224. [

In the upper region of the contact electrode 262b, a branch electrode 272 may be disposed on the side surface. Branch electrode 272 connects adjacent contact electrodes 262b to each other, and a specific configuration will be described later with reference to Fig.

The insulating layer 280 is disposed on the upper surface of the base layer 262a constituting the first electrode 262 and on the side surface of the contact electrode 262b so that the first electrode 262 is electrically connected to the second conductive semiconductor layer 226, As shown in Fig. The insulating layer 280 may also be disposed on the lower and lateral sides of the branch electrodes 272.

A conductive layer 260 made of a conductive material is disposed on the insulating layer 280. A second electrode 266 is disposed on the conductive layer 260 on the side of the light emitting structure 220, Lt; RTI ID = 0.0 > 226 < / RTI >

The conductive layer 260 may be made of GaN and the contact characteristics between the second electrode 266 and the second conductive type semiconductor layer 226 may be poor. The conductive layer 260 may be formed on the second electrode 266 The contact characteristics with the second conductivity type semiconductor layer 226 can be excellent.

The first electrode 262 and the second electrode 266 may include at least one of Al, Ti, Cr, Ni, Cu, Or a multi-layer structure.

The light emitting structure 220 may be disposed on the conductive layer 260 and may include a first conductive semiconductor layer 222, an active layer 224, and a second conductive semiconductor layer 226.

The first conductive semiconductor layer 222 may be formed of a compound semiconductor such as Group III-V or Group II-VI, and may be doped with a first conductive dopant.

More specifically, the first conductive semiconductor layer 222 is a semiconductor having a composition formula of Al _x In _y Ga _(1-xy) N (0? X? 1, 0? _Y? 1, 0? _X + Material, AlGaN, GaN, InAlGaN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP.

When the first conductivity type semiconductor layer 222 is an n-type semiconductor layer, the first conductivity type dopant may include n-type dopants such as Si, Ge, Sn, Se, and Te. The first conductive semiconductor layer 222 may be formed as a single layer or a multilayer, but the present invention is not limited thereto.

The active layer 224 is disposed between the first conductivity type semiconductor layer 222 and the second conductivity type semiconductor layer 226 and may include a single well structure, a multiple well structure, a single quantum well structure, a multi quantum well (MQW) Well structure, a quantum dot structure, or a quantum wire structure, and may be formed of, for example, a multiple quantum well structure.

InGaN / InGaN, InGaN / InGaN, AlGaN / GaN, InAlGaN / GaN, GaAs (InGaAs), and AlGaN / AlGaN / InGaN / GaN, / AlGaAs, GaP (InGaP) / AlGaP, and InGaN / AlGaN.

The well layer may be formed of a material having an energy band gap smaller than the energy band gap of the barrier layer.

The second conductive semiconductor layer 226 may be formed of a semiconductor compound. The second conductive semiconductor layer 226 may be formed of a compound semiconductor such as a Group III-V or a Group II-VI, and may be doped with a second conductive dopant. The second conductive semiconductor layer 226 may be a semiconductor material having a composition formula of In _x Al _y Ga _{1 -xy} N (0? X? 1, 0? _Y? 1, 0? _X + y? For example, the second conductivity type semiconductor layer 226 may be formed of Al _x Ga _(1-x) N. The second conductivity type semiconductor layer 226 may be formed of Al _x Ga _{y (1-x)} N.

When the second conductivity type semiconductor layer 226 is a p-type semiconductor layer, the second conductivity type dopant may be a p-type dopant such as Mg, Zn, Ca, Sr, and Ba. The second conductivity type semiconductor layer 226 may be formed as a single layer or a multilayer, but is not limited thereto.

The active layer 224 and the first conductivity type semiconductor layer 222 are etched from the second conductivity type semiconductor layer 226 to a portion of the first conductivity type semiconductor layer 222 in the plurality of regions of the light emitting structure 220, The layer 222 may be exposed and the first electrode 262, specifically, the contact electrode 262b described above, may be disposed in contact with the surface of the exposed first conductive semiconductor layer 222. [

The light emitting structure 220 is made of AlGaN in particular and is capable of emitting light in the ultraviolet wavelength range, and in particular, can emit light in the UV-BE or UV-C range. The ultraviolet rays can be classified into three types (UVA, UVB, UVC) depending on the wavelength range. UVA is an ultraviolet ray having a wavelength range of 320 to 400 nm, UVB is ultraviolet ray having a wavelength range of 290 nm to 320 nm, and UVC is ultraviolet ray having a wavelength band of 290 nm or less.

The surface of the first conductivity type semiconductor layer 222 may have irregularities to improve light extraction efficiency.

The side surfaces of the light emitting structure 220 may be inclined and the passivation layer 290 may be disposed around the light emitting structure 220 to protect the light emitting structure 220 as shown in FIG. The passivation layer 290 may be made of an insulating material, and the insulating material may be made of a non-conductive oxide or nitride. As an example, the passivation layer 290 may comprise a silicon oxide (SiO ₂ ) layer, an oxynitride layer, or an aluminum oxide layer.

3 is a cross-sectional view taken along line I-I 'of FIG.

A plurality of contact electrodes 262b are arranged in a lattice pattern, and a total of 36 contact electrodes 262b are arranged at regular intervals, six in each of the horizontal and vertical directions, but the present invention is not limited thereto.

The branch electrodes 272 are arranged in a horizontal direction connecting the contact electrodes 262b to each other. The branch electrodes 272 may be arranged in a mesh shape. As shown in FIG. 2, the branched electrodes 272 may contact the first conductive semiconductor layer 222 in the upper region, although the insulating layer 280 may be disposed around the branched electrodes 272.

In Fig. 3, the pitch d of the contact electrodes 262b may be 40 micrometers to 800 micrometers, and the pitch of the branch electrodes 272 may be the same as the pitch of the contact electrodes 262b. The pitch d may be changed according to the size of the light emitting structure 220 or the like.

The width W1 of the branch electrode 272 and the width of the insulating layer 280 may be several tens nanometers to several hundreds of nanometers and may be varied depending on the size of the light emitting structure 220 and the pitch d .

In FIG. 3, a second electrode (not shown) may be disposed on the upper right region and the lower right region of the first conductive semiconductor layer 222. In FIG. 3, the region where the branch electrodes 272 are arranged is referred to as a first region, and the region where the second electrode (not shown) can be disposed is referred to as a second region. As shown in FIG. 2, Direction.

The light emitting device 200 according to the embodiment is configured such that the first electrode 262 is disposed as the base layer 262a and the contact electrode 262b and the first electrode 262 is disposed in the first conductivity type semiconductor layer 222 at the contact electrode 262b The branch electrodes 272 can be extended. Accordingly, a current is uniformly injected into the entire region of the first conductivity type semiconductor layer 222, and electrons and holes are combined in the entire region of the active layer 224 to emit light.

4 is a view showing an embodiment of a light emitting device package in which a light emitting device is disposed.

The light emitting device package 400 may include a first lead frame 421 and a second lead frame 422 disposed in a package body 410 having a cavity and the first lead frame 421 and the second lead frame 422 The lead frame 422 is disposed through the package body 410, but may be disposed in a different shape.

The light emitting device 200 may be the same as that shown in Figs. 2 and 3, and may be electrically connected to the first lead frame 421 and the second lead frame 422 by wires 430, And the molding part 440 may include the fluorescent material 445. In addition,

In the light emitting device package 400 of FIG. 4, the light of the first wavelength range, for example, the ultraviolet wavelength range is emitted from the light emitting device 200, and the phosphor 445 is excited by the light of the first wavelength range It is possible to emit light in the second wavelength range that is longer in wavelength.

The light emitting device package may include one or more light emitting devices according to the above-described embodiments, but the present invention is not limited thereto.

The above-described light emitting device package can be used in a sterilizing apparatus or as a light source of an illumination system, for example, in an image display apparatus and a lighting apparatus.

The above-described light emitting devices may be arranged in a line on a circuit board to be used in a lighting device or as an edge type light source in an image display device.

The light emitting device may be a plurality of light emitting devices arranged on a circuit board in a plurality of rows and columns, and may be used as a light source of direct type in a video display device.

5 is a view showing an embodiment of a sterilizing apparatus in which a light emitting element is disposed.

5, the sterilizing apparatus 500 includes a light emitting module 510 mounted on one surface of a housing 501, diffusive reflecting members 530a and 530b for diffusing light of emitted deep ultraviolet wavelength band, And a power supply unit 520 for supplying available power required by the light emitting module unit 510.

The housing 501 may have a rectangular structure and may be formed as a unitary or compact structure including both the light emitting module unit 510 and the diffusive reflective members 530a and 530b and the power supply unit 520. [ In addition, the housing 501 may have a material and shape effective for discharging the heat generated inside the sterilizing apparatus 500 to the outside. For example, the material of the housing 501 may be made of any one of Al, Cu, and alloys thereof. Therefore, the heat transfer efficiency with the outside air of the housing 501 is improved, and the heat radiation characteristic can be improved.

Alternatively, the housing 501 may have a distinctive external surface shape. For example, the housing 501 may have an external surface shape that is protruded, for example, in a corrugation or a mesh or an unspecified concavo-convex shape. Accordingly, the heat transfer efficiency with the outside air of the housing 501 is further improved, and the heat radiation characteristic can be improved.

On the other hand, attachment plates 550 may be disposed on both ends of the housing 501. The attachment plate 550 means a member of a bracket function used to lock and fix the housing 501 to the entire equipment as illustrated. The attachment plate 550 may protrude from both ends of the housing 501 in one direction. Here, the one direction may be an inner direction of the housing 501 in which deep ultraviolet rays are emitted and diffuse reflection occurs.

Thus, the attachment plate 550 provided on both ends from the housing 501 provides a fixing area with the entire facility apparatus, so that the housing 501 can be more effectively fixedly installed.

The attachment plate 550 may take any of the form of a screw fastening means, a rivet fastening means, an adhesive means, and an attaching / detaching means, and the manner of these various fastening means is obvious at the level of those skilled in the art. do.

On the other hand, the light emitting module unit 510 is disposed on one surface of the housing 501. The light emitting module unit 510 emits ultraviolet rays to sterilize microorganisms in the air. For this, the light emitting module unit 510 includes a substrate 512 and a plurality of light emitting device packages mounted on the substrate 512.

The substrate 512 is arranged in a single row along the inner surface of the housing 501 and may be a PCB including a circuit pattern (not shown). However, the substrate 512 may include not only a general PCB but also a metal core PCB (MCPCB), a flexible PCB, and the like, but the present invention is not limited thereto.

Next, the diffuse reflection members 530a and 530b refer to a reflection plate type member formed to forcibly diffuse the deep ultraviolet rays emitted from the light emitting module unit 510 described above. The front surface shape and the arrangement shape of the diffusely reflecting reflection members 530a and 530b may have various shapes. (For example, a radius of curvature) of the diffusive reflection members 530a and 530b is slightly changed, the diffused deep ultraviolet rays are irradiated to overlap with each other to increase the irradiation intensity, or the width of the region to be irradiated increases .

The power supply unit 520 receives power and supplies necessary power to the light emitting module unit 510. The power supply unit 520 may be disposed in the housing 501 described above.

As illustrated in FIG. 5, the power connection 540 may be in the form of a surface, but may take the form of a socket or cable slot through which an external power cable (not shown) may be electrically connected. Also, the power cable has a flexible extension structure and can be easily connected to an external power source.

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 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.

100, 200: light emitting device 120, 220: light emitting structure
122, 222: first conductivity type semiconductor layers 124, 224: active layer
126, and 226: a second conductivity type semiconductor layer
162, 262: first electrodes 166, 266: second electrodes
252: Ohmic layer 254: Reflective layer
256: bonding layer 258: supporting substrate
260: conductive layer 262a: base layer
262b: contact electrode 272: branch electrode
280: insulating layer 290: passivation layer
400: light emitting device package 410: package body
421: first lead frame 422: second lead frame
430: wire 440: molding part
445: phosphor 500: sterilizing device

Claims (10)

A first conductive semiconductor layer, an active layer on the first conductive semiconductor layer, and a second conductive semiconductor layer on the active layer, wherein the active layer and the first conductive semiconductor layer The light emitting structure being etched to a portion of the first conductive semiconductor layer to expose the first conductive semiconductor layer;
A plurality of first electrodes disposed on the exposed region of the first conductive type semiconductor layer;
A plurality of branched electrodes connecting the plurality of first electrodes in a horizontal direction; And
And a second electrode disposed on the second conductive type semiconductor layer. The method according to claim 1,
And an insulating layer electrically isolating the first electrode from the second conductive type semiconductor layer. The method according to claim 1,
And the pitch of the branch electrodes is 40 micrometers to 800 micrometers. 4. The method according to any one of claims 1 to 3,
Wherein the first conductive semiconductor layer and the second conductive semiconductor layer include AlGaN. 4. The method according to any one of claims 1 to 3,
And a conductive layer disposed under the second conductive type semiconductor layer. 6. The method of claim 5,
Wherein the conductive layer comprises GaN. The method according to claim 6,
And the GaN is doped with the second conductive dopant. The method according to claim 1,
Wherein the plurality of branch electrodes are arranged in a mesh shape. The method according to claim 1,
Wherein the second electrode is disposed in a first region of at least one corner of the light emitting structure. 10. The method of claim 9,
Wherein the plurality of first electrodes are disposed in a second region of the light emitting structure.

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