KR20170093574A - Light emitting device - Google Patents

Abstract

An embodiment discloses a light emitting device. The light emitting device includes a light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer; a first pad electrically connected to the first semiconductor layer; a second pad electrically connected to the second semiconductor layer; and at least one first electrode disposed between the first semiconductor layer and the first pad. The first electrode includes a first region extended toward the second pad, and a second region bent along the side of the second pad. It is possible to provide a light emitting device capable of preventing a short circuit between an N-type electrode and a P-type pad.

Description

[0001] LIGHT EMITTING DEVICE [0002]

An embodiment relates to a light emitting element.

LIGHT EMITTING DEVICE is a compound semiconductor device that converts electric energy into light energy. It can realize various colors by controlling composition ratio of compound semiconductor.

The nitride semiconductor light emitting device has advantages of low power consumption, semi-permanent lifetime, fast response speed, safety, and environmental friendliness compared to conventional light sources such as fluorescent lamps and incandescent lamps. Therefore, applications are increasingly being applied to a backlight of a liquid crystal display (LCD), a white light emitting diode (LED) lighting device, and an automobile headlight.

The embodiment provides a light emitting device capable of preventing a short circuit between an N-type electrode and a P-type pad.

A light emitting device according to an embodiment includes a light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer; A first pad electrically connected to the first semiconductor layer; A second pad electrically connected to the second semiconductor layer; And at least one first electrode disposed between the first semiconductor layer and the first pad, the first electrode having a first region extending toward the second pad and a second region extending along the side of the second pad, And the second region.

Wherein the second pad comprises a first surface and a second surface facing each other and a third surface and a fourth surface facing each other connecting the first surface and the second surface, And the second region may be bent along the first surface.

The first electrode may include a third region bent along the third or fourth surface.

The first electrode may include a fourth region connected to the third region and folded along the fourth surface.

The first electrode may be folded along the second pad to form a loop surrounding the second pad.

The loop may include a plurality of branched electrodes protruding toward the second pad.

According to the embodiment, short-circuiting between the N-type electrode and the P-type pad can be prevented even when microcracks are generated due to an external impact.

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 plan view of a light emitting device according to an embodiment of the present invention,
Fig. 2 is a sectional view in the AA direction in Fig. 1,
3 is a plan view of a conventional light emitting device,
4 is a cross-sectional view taken along line BB in Fig. 3,
5 is a plan view of a light emitting device according to another embodiment of the present invention,
6 is a plan view of a light emitting device according to another embodiment of the present invention,
7 is a simulation result of measuring the light emission distribution of the light emitting device.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the embodiments of the present invention are not intended to be limited to the specific embodiments but include all modifications, equivalents, and alternatives falling within the spirit and scope of the embodiments.

Terms including ordinals, such as first, second, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the embodiments, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

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 will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

1 is a plan view of a light emitting device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along a line A-A of FIG. 1, FIG. 3 is a plan view of a conventional light emitting device, and FIG.

1 and 2, a light emitting device 100 according to an embodiment includes a light emitting structure 120 including a first semiconductor layer 121, an active layer 122, and a second semiconductor layer 123, A first pad 150 electrically connected to the first semiconductor layer 121, a second pad 160 electrically connected to the second semiconductor layer 123, and a second pad 160 electrically connected to the first semiconductor layer 121, And at least one first electrode (151) disposed between the second electrode (150).

One side of the light emitting structure 120 is covered with an insulating layer and the first pad 150 and the second pad 160 pass through the insulating layer to form the first semiconductor layer 121 and the second semiconductor layer 122, Lt; / RTI >

A plurality of first electrodes 151 are disposed on the second pad 150 and include sub electrodes 152 electrically connected to each other. The sub electrode 152 connected to the outermost first electrode 151 includes a first region 152a extending toward the second pad 160 and a second region 152b extending toward the second pad 160 along the side of the second pad 160. [ Regions 152b and 152c. That is, the sub electrode 152 does not overlap with the second pad 160 on the plane. The first electrode 151 and the sub electrode 152 may have a Cr / Ni / Au layer structure and each may have a thickness of 30/100/700 nm.

The second pad 160 may have a rectangular shape including four sides. The second pad 160 includes a first surface 160a and a second surface 160b facing each other and a third surface 160c connecting the first surface 160a and the second surface 160b and facing each other, And a fourth surface 160d. The width of the second pad 160 may be between 400 and 800 um.

The first region 152a of the sub-electrode 152 extends toward the first surface 160a. The second regions 152b and 152c are bent along the first surface 160a and are disposed between the third surface 160c and the edge 100a of the light emitting device or between the fourth surface 160d and the edges 100a As shown in FIG. The sub electrode 152 may have a width of 10 mu m to 20 mu m and a thickness of 0.1 mu m to 1.0 mu m.

For example, the distance between the second regions 152b and 152c and the second pad 160 may be narrower than the distance between the second regions 152b and 152c and the edge 100a of the light emitting device, but is not limited thereto.

The sub electrode 152 may further include a third region 152d that is bent along the third surface 160c or the fourth surface 160d to surround the second surface 160b.

3 and 4, when the N-type electrode 2 is extended and disposed on the P-type pad 1, if cracks are generated in the insulating layer due to an external impact or the like, the N-type electrode 2 and the P- The device 1 may be short-circuited and the device may be defective. If a crack is generated in the P-type pad 1, the solder may be diffused into the chip to break the chip characteristics.

Since the first electrode 151 and the second pad 160 do not overlap with each other on a plane, even if a crack occurs due to an external impact or the like, the short circuit between the first electrode 151 and the second pad 160 Can be prevented.

Referring to FIG. 5, the sub electrode 152 may be formed to entirely cover the side surface of the second pad 160, but may surround only some of the side surfaces 160b and 160c.

Referring to FIG. 6, the first electrodes 151 may include branch electrodes 153 protruding toward the second pad 160. The width of the sub electrode 152 may be 10um to 20um, and the width of the branch electrode 153 may be 3um to 10um. The distance between the branch electrodes 153 facing each other may be within 600 nm.

The second pad 160 may have a groove 162 at a portion corresponding to the branch electrode. Therefore, the branched electrodes 153 and the second pads 160 do not overlap on a plane.

Referring again to FIG. 2, the substrate 110 includes a conductive substrate or an insulating substrate. The substrate 110 may be a material suitable for semiconductor material growth or a carrier wafer. The substrate 110 may be formed of a material selected from the group consisting of sapphire (Al ₂ O ₃ ), GaN, SiC, GaAs, GaN, ZnO, Si, GaP, InP and Ge.

The light emitting structure 120 is disposed on one surface 111 of the substrate 110 and includes a first semiconductor layer 121, an active layer 122, and a second semiconductor layer 123. The light emitting structure 120 may be divided into a plurality of portions in the process of cutting the substrate 110.

The first semiconductor layer 121 may be a compound semiconductor such as a III-V group or a II-VI group, and the first semiconductor layer 121 may be doped with a first dopant. The first semiconductor layer 121 is a semiconductor material having a composition formula of In _{x 1} Al _{y 1} Ga ₁ -x ₁ -y ₁ N (0? X _{1? 1} , 0? Y _{1? 1} , 0? X 1 + _{y 1? 1} ) 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 semiconductor layer 121 doped with the first dopant may be an n-type semiconductor layer.

The active layer 122 is a layer where electrons (or holes) injected through the first semiconductor layer 121 and holes (or electrons) injected through the second semiconductor layer 123 meet. The active layer 122 transitions to a low energy level as electrons and holes are recombined, and light having a wavelength corresponding thereto can be generated. There is no limitation on the emission wavelength in this embodiment.

The active layer 122 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, Is not limited thereto.

The second semiconductor layer 123 may be formed of a compound semiconductor such as a group III-V or II-VI group, and the second semiconductor layer 123 may be doped with a second dopant. The second semiconductor layer 123 may be a semiconductor material having a composition formula of In _{x 5} Al _{y 2} Ga _{1 -x5-y 2} N (0? X 5? 1, 0? Y 2? 1, 0? X 5 + y 2? 1) , GaP, GaAs, GaAsP, and AlGaInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, or Ba, the second semiconductor layer 123 doped with the second dopant may be a p-type semiconductor layer.

Although not shown, an electron blocking layer (EBL) may be disposed between the active layer 122 and the second semiconductor layer 123. The electron blocking layer can block the flow of electrons supplied from the first semiconductor layer 121 to the second semiconductor layer 123 and increase the probability of recombination of electrons and holes in the active layer 122.

The light emitting structure 120 may have a first groove H1 through which the first semiconductor layer 121 is exposed through the second semiconductor layer 123 and the active layer 122. [ The first semiconductor layer 121 can also be partially etched by the first trench H1. The first grooves H1 may be plural. The first electrode 151 may be disposed in the first groove H1 and may be electrically connected to the first semiconductor layer 121. [ The second electrode 131 may be disposed under the second semiconductor layer 123.

The first electrode 151 and the second electrode 131 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), SnO, InO, INZnO, ZnO, IrOx, RuOx, NiO, , Cr, and an optional compound or alloy thereof, and may be formed of at least one layer. The thickness of the ohmic electrode is not particularly limited.

The protective layer 141 may isolate the first electrode 151 from the active layer 122 and the second semiconductor layer 123. The protective layer 141 may be formed entirely in the light emitting structure 120 except for a region where the first electrode 151 and the second electrode 131 are formed.

The protective layer 141 may include an insulating material or an insulating resin formed of at least one of oxide, nitride, fluoride, and sulfide having at least one of Al, Cr, Si, Ti, Zn, and Zr. The protective layer 141 may be selectively formed, for example, of SiO2, Si3N4, Al2O3, and TiO2. The protective layer 141 may be formed as a single layer or a multilayer, but is not limited thereto.

The reflective electrode layer 132 may be disposed on the second electrode 131. The reflective electrode layer 132 may be formed of a metallic or non-metallic material. The metallic reflective electrode layer 132 may be formed of a metal such as In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, W, Ti, Ag, Cr, Mo, , Ni, Cu, and WTi.

The first insulating layer 142 entirely covers the light emitting structure 120 in which the reflective electrode layer 132 is disposed. The first insulating layer 142 may include an insulating material or an insulating resin formed of at least one of oxides, nitrides, fluorides, and sulfides having at least one of Al, Cr, Si, Ti, Zn, and Zr. The first insulating layer 142 may be selectively formed of, for example, SiO2, Si3N4, Al2O3, or TiO2. The first insulating layer 142 may be formed as a single layer or a multilayer, but is not limited thereto.

The first insulating layer 142 may be a reflective layer. Specifically, the first insulating layer 142 includes a structure in which a first layer having a first refractive index and a second layer having a second refractive index are alternately stacked two or more layers, and the first layer and the second layer have a refractive index And may be formed of a conductive or insulating material between 1.5 and 2.4. Such a structure may be a DBR (distributed bragg reflection) structure. Further, it may be a structure in which a dielectric layer having a low refractive index and a metal layer are laminated (Omnidirectional Reflector).

With this structure, most of the light emitted from the active layer 122 toward the second semiconductor layer 123 can be reflected toward the substrate 110 side. Therefore, the reflection efficiency can be increased and the light extraction efficiency can be improved.

The first pad 150 may be electrically connected to the first electrode 151 through the first insulating layer 142. The area of the first electrode 151 becomes closer to the substrate 110 while the area of the first pad 150 becomes smaller as the area of the first pad 150 becomes closer to the substrate 110.

The second pad 160 may be electrically connected to the second electrode 131 and the reflective electrode layer 132 through the first insulating layer 142.

The first and second pads 150 and 160 may be formed of a material selected from the group consisting of In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, Cr, Mo, Nb, Al, Ni, Cu, and WTi.

The light emitting device of the embodiment further includes optical members such as a light guide plate, a prism sheet, and a diffusion sheet, and can function as a backlight unit. Further, the light emitting element of the embodiment can be further applied to a display device, a lighting device, and a pointing device.

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

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

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 dissipates heat of the light source module, and a power supply unit that processes or converts an electric signal provided from the outside and provides the light source module . Further, the lighting device may include a lamp, a head lamp, or a street lamp or the like.

It will be apparent to those skilled in the art that various changes, substitutions, and alterations can be made hereto without departing from the spirit and scope of the invention as defined in the appended claims. Will be apparent to those of ordinary skill in the art.

Claims (6)

A light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer;
A first pad electrically connected to the first semiconductor layer;
A second pad electrically connected to the second semiconductor layer; And
And at least one first electrode disposed between the first semiconductor layer and the first pad,
Wherein the first electrode includes a first region extending toward the second pad and a second region bent along a side of the second pad. The method according to claim 1,
The second pad includes a first surface and a second surface facing each other, and a third surface and a fourth surface which connect the first surface and the second surface and face each other,
Wherein the first region of the first electrode extends toward the first surface and the second region is bent along the first surface. 3. The method of claim 2,
And the first electrode includes a third region bent along the third or fourth surface. The method of claim 3,
And the first electrode includes a fourth region connected to the third region and being bent along the fourth surface. The method according to claim 1,
Wherein the first electrode is folded along the second pad to form a loop surrounding the second pad. 6. The method of claim 5,
And the loop includes a plurality of branched electrodes protruding toward the second pad.

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