KR20120009829A - Light emitting element - Google Patents

Abstract

The light emitting device according to the embodiment has a structure that facilitates adhesion between the passivation disposed on the side of the light emitting structure and the electrode layer disposed on the passivation, the substrate is disposed on the substrate, the first semiconductor A light emitting structure comprising a layer, a second semiconductor layer and an active layer formed between the first and second semiconductor layers, an insulating layer disposed on a portion of the upper surface of the substrate, disposed on the first semiconductor layer, It provides a light emitting device comprising a first electrode layer extending along a side surface disposed on the insulating layer, a passivation disposed between the side surface of the light emitting structure and the first electrode layer and a protective cap layer disposed on the first electrode layer. .

Description

Light-emitting device

The embodiment relates to a light emitting device, and more particularly, to a light emitting device having a structure that facilitates adhesion between a passivation disposed on the side of the light emitting structure and an electrode layer disposed on the passivation.

In general, a light emitting diode (LED), which is one of light emitting devices, is a semiconductor device that emits light based on recombination of electrons and holes, and is widely used as a light source in optical communication and electronic devices.

In the light emitting diode, the frequency or wavelength of light emitted is a function of the band gap of the material used for the semiconductor device. When using a semiconductor material having a small band gap, photons of low energy and long wavelength are generated, and a wide band gap is generated. When using the semiconductor material which has, the photon of a short wavelength arises.

For example, AlGaInP materials generate red wavelengths of light, while silicon carbide (SiC) and group III nitride based semiconductors, particularly GaN, generate blue or ultraviolet wavelengths of light.

Among them, since nitride light emitting diodes cannot form GaN bulk single crystals, a substrate suitable for the growth of GaN crystals should be used, and a sapphire substrate is typically used.

Recently, high brightness is required to use a light emitting device as an illumination light source, and in order to achieve such high brightness, research is being conducted to manufacture a light emitting device capable of increasing light emission efficiency by uniformly spreading current.

An object of the embodiment is to provide a light emitting device having a structure that is easy to improve the adhesion between the passivation disposed on the side of the light emitting structure and the electrode layer disposed on the passivation.

The light emitting device according to the embodiment includes a substrate, a light emitting structure including a first semiconductor layer, a second semiconductor layer, and an active layer formed between the first and second semiconductor layers, and a partial region of an upper surface of the substrate. An insulating layer disposed on the first semiconductor layer, the first electrode layer disposed along the side surface of the light emitting structure and disposed on the insulating layer, and disposed between the side surface of the light emitting structure and the first electrode layer. Passivation and a protective cap layer disposed on the first electrode layer.

The light emitting device according to the embodiment has an advantage of improving adhesion between the electrode layer and the passivation by disposing a protective cap layer on the electrode layer.

In addition, the light emitting device according to the embodiment has the advantage that the adhesion between the electrode layer and the passivation is improved, the reliability is improved and the light loss is reduced.

1 is a cross-sectional view illustrating a structure of a light emitting device according to a first embodiment.
2 is a cross-sectional view illustrating a structure of a light emitting device according to a second embodiment.
3 is a top view illustrating the light emitting device illustrated in FIG. 1.
4 to 9 are process charts showing the manufacturing method of the light emitting device shown in FIG.

Prior to the description of the embodiments, the substrate, each layer region, pad, or pattern of each layer (film), region, pattern, or structure referred to in the embodiment is "on", "below ( "on" and "under" include all that is formed "directly" or "indirectly" through other layers. In addition, the criteria for the top or bottom of each layer will be described with reference to the drawings.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. Thus, the size of each component does not fully reflect its actual size.

In addition, the angle and direction mentioned in the process of describing the structure of the light emitting device in the embodiment are based on those described in the drawings. In the description of the structure of the light emitting device in the specification, reference points and positional relationship with respect to angles are not explicitly referred to, refer to the related drawings.

1 is a cross-sectional view illustrating a structure of a light emitting device according to a first embodiment, and FIG. 2 is a cross-sectional view illustrating a structure of a light emitting device according to a second embodiment.

1 and 2, the light emitting device 100 includes a substrate 110, an insulating layer 130 disposed on an upper surface of an outer circumference of the substrate 110, a light emitting structure on the substrate 110, and the insulating layer 130. 140, the first electrode layer 170 and the light emitting structure 140 are electrically connected to an upper surface of the light emitting structure 140 and at least a portion of the light emitting structure 140 is disposed on the insulating layer 130. And a passivation 150 formed between the first electrode layer 170 to insulate the light emitting structure 140 and the first electrode layer 170, and a protective cap layer 180 disposed on the first electrode layer 170. have.

The light emitting structure 140 includes a first semiconductor layer 142, an active layer 144 under the first semiconductor layer 142, and a second semiconductor layer 146 under the active layer 144, which generate light. Form a structure.

The substrate 110 and the first electrode layer 170 receive power from an external power source, and provide power to the light emitting device 100.

Hereinafter, the light emitting devices 100 according to the first and second embodiments will be described in detail with reference to components.

The substrate 110 may include titanium (Ti), chromium (Cr), nickel (Ni), aluminum (Al), platinum (Pt), gold (Au), tungsten (W), copper (Cu), molybdenum (Mo) or It may be formed of at least one of the semiconductor substrate implanted with impurities.

The reflective layer 120 may be formed on the substrate 110. The reflective layer 120 may improve light emission efficiency of the light emitting device 100 by reflecting light incident from the light emitting structure 140 and increasing the amount of light emitted to the outside.

The reflective layer 120 may be formed of a metal or an alloy including at least one of silver (Ag), aluminum (Al), platinum (Pt), palladium (Pd), or copper (Cu) having high reflectance.

Although not shown, an adhesive layer (not shown) may be formed between the reflective layer 120 and the substrate 110 to enhance the interfacial bonding force between the two layers, but is not limited thereto.

An insulating layer 130 may be formed in the peripheral area of the upper surface of the reflective layer 120. The insulating layer 130 may prevent an electrical short between the light emitting structure 140 and the substrate 110.

The insulating layer 130 is electrically insulating and preferably formed of a transparent material to minimize light loss. For example, Si0 ₂ , SixOy, Si ₃ N ₄ , SixNy, SiOxNy, Al ₂ O ₃ , TiO ₂ , ITO, AZO, ZnO and the like may be formed by selecting at least one.

An ohmic layer 125 may be formed on an upper surface of the reflective layer 120 and an inner side of the insulating layer 130. The ohmic layer 125 may be formed for ohmic contact between the light emitting structure 140, which is a semiconductor layer, and the substrate 110 or the reflective layer 120. For example, ITO, Ni, Pt, Ir, Rh, Ag It may be formed to include at least one of.

In addition, when the substrate 110 or the reflective layer 120 in contact with the light emitting structure 140 is in ohmic contact, the ohmic layer 125 may not be formed.

The light emitting structure 140 may be formed on the ohmic layer 125. The light emitting structure 140 includes a first semiconductor layer 142, an active layer 144 under the first semiconductor layer 142, and a second semiconductor layer 146 under the active layer 144.

The first semiconductor layer 142 may include, for example, an n-type semiconductor layer, wherein the n-type semiconductor layer is formed of InxAlyGa1-x-yN (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + A semiconductor material having a compositional formula of y ≦ 1), for example, InAlGaN, GaN, AlGaN, InGaN, AlN, InN, or the like, may be selected, and n-type dopants such as Si, Ge, Sn, and the like may be doped.

The active layer 144 may include, for example, a semiconductor material having a compositional formula of InxAlyGa1-x-yN (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1), and both It may include at least one of a quantum wire structure, a quantum dot structure, a single quantum well structure, or a multi quantum well structure (MQW). The active layer 144 receives electrons and holes from the first and second semiconductor layers 142 and 146, and the electrons and holes are recombined in the active layer 144 to generate light energy.

For example, the second semiconductor layer 146 may be implemented as a p-type semiconductor layer. The p-type semiconductor layer may include InxAlyGa1-x-yN (0≤x≤1, 0≤y≤1, 0≤x + A semiconductor material having a compositional formula of y ≦ 1) may be selected from, for example, InAlGaN, GaN, AlGaN, InGaN, AlN, InN, and the like, and p-type dopants such as Mg, Zn, Ca, Sr, and Ba may be doped. .

However, the p-type dopant may be doped in the first semiconductor layer 142 and the n-type dopant may be doped in the second semiconductor layer 146, or a third conductive semiconductor layer may be further formed on the second semiconductor layer 146. In addition, the light emitting device 100 may include any one of np, pn, npn or pnp junction.

An isolation etching for separating the plurality of chips into individual chip units may be performed on the side surface of the light emitting structure 140. The side surface of the light emitting structure 140 may be inclined by the isolation etching, and the insulating layer 130 may be exposed.

In an embodiment, a region above the insulating layer 130 on which the first electrode layer 170 is formed may be secured by the isolation etching.

The first electrode layer 170 may be electrically connected to an upper surface of the light emitting structure 140, that is, the first semiconductor layer 142, and at least a portion thereof may be disposed on the insulating layer 130. That is, the first electrode layer 170 may extend from an upper surface of the first semiconductor layer 142 and be disposed on the insulating layer 130 along the side surface of the light emitting structure 140.

The material of the first electrode layer 170 may be electrically conductive, and may be a metal or a conductive nonmetal making ohmic contact with the first semiconductor layer 142. For example, the first electrode layer 170 may include Cu, Ti, Zn, Au, Ni, Pt, Ir, Rh, Ag, ITO, IZO (In-ZnO), GZO (Ga-ZnO), and AZO (Al-). ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrOx, RuOx, RuOx / ITO, Ni / IrOx / Au, Ni / IrOx / Au / ITO or ZnO. .

Meanwhile, in the first and second embodiments, the shape of the first electrode layer 170 may vary depending on the transparency of the material.

In this case, according to the first embodiment illustrated in FIG. 1, in order to electrically connect the light emitting device 100 to an external power source, a wire or the like may be connected to an area of the first electrode layer 170 formed on the insulating layer 130. have. Therefore, the light emitted from the light emitting structure 140 may be minimized by the wire, and the like, and damage to the light emitting structure 140 that may occur in the process of attaching the wire or the like may be prevented.

In addition, according to the second embodiment illustrated in FIG. 2, in order to electrically connect the light emitting device 100 to an external power source, a bonding metal layer bonded to the first electrode layer 170 formed on the insulating layer 130 may be used. Since it can be connected by 160, it may have the same characteristics in the first embodiment.

1 and 2, the protective cap layer 180 is disposed on the first electrode layer 170.

That is, the protective cap layer 180 is disposed to overlap the first electrode layer 170, and is disposed to expose at least a portion of the first electrode layer 170 disposed on the insulating layer 130. That is, the wire is connected to the exposed portion of the first electrode layer 170 to supply power.

Here, the protective cap layer 180 may include the same material as at least one of the passivation 150 or the insulating layer 130, but is not limited thereto.

That is, the protective cap layer 180 may include at least one of Si0 ₂ , SixOy, Si ₃ N ₄ , SixNy, SiOxNy, Al ₂ O ₃ , TiO ₂ .

The protective cap layer 180 may improve adhesion between the insulating layer 130 and the first electrode layer 170. That is, the side of the light emitting structure 140 may have an inclination by the isolation etching described above, and may expose the insulating layer 130, but may be formed between the insulating layer 13 and the light emitting structure 140. When the first electrode layer 170 is disposed due to the step, adhesion is deteriorated, and as a result, the upper surface of the first electrode layer 170 is prevented from being separated from the first electrode layer 170 and the insulating layer 130. The protective cap layer 180 may be disposed on the substrate.

As such, the protective cap layer 180 may enhance adhesion between the first electrode layer 170 and the insulating layer 130.

3 is a top view illustrating the light emitting device illustrated in FIG. 1.

Referring to FIG. 3, the first electrode layer 170 is shown to have a predetermined pattern. However, the pattern may not be formed and may be formed of a transparent or opaque material.

That is, the first electrode layer 170 may be configured to spread external power uniformly over the entire area of the upper surface of the first semiconductor layer 142 and to minimize light loss of light emitted from the light emitting structure 140. It may have a predetermined pattern.

For example, as shown in FIG. 3, the first electrode layer 170 formed on the upper surface of the first semiconductor layer 142 has a pattern such as a lattice pattern or a spiral pattern, and extends from the pattern by a thin line to emit light. It may be formed on the insulating layer 130 along the side of the structure 140. The shape of the first electrode layer 170 is not limited.

On the other hand, the first electrode layer 170 may be formed to have a multi-layer structure, but is not limited thereto.

Here, a protective cap layer 180 may be disposed on an upper surface of the first electrode layer 170 to enhance adhesion between the first electrode layer 170 and the insulating layer 130.

That is, the protective cap layer 180 is exposed to at least a portion of the first electrode layer 170, the wire is applied to the exposed first electrode layer 170, it is possible to supply power to the light emitting device 100 from an external power source. have.

As such, in the embodiment, since the wire is not attached to the light emitting structure 140 and the wire is attached to the first electrode layer 170 formed on the insulating layer 130, the light loss caused by the wire is minimized and the It is possible to prevent damage to the light emitting structure 140 that may occur in the process of attaching the wire.

The passivation 150 may be formed between the first electrode layer 170 and the light emitting structure 140, that is, the lower portion of the first electrode layer 170 to insulate the two layers. That is, the passivation 150 may be formed on the side surface of the light emitting structure 140 to prevent the light emitting structure 140 and the first electrode layer 170 from being electrically shorted.

Meanwhile, the passivation 150 may be further formed between the insulating layer 130 and the first electrode layer 170, but is not limited thereto.

The passivation 150 preferably has electrical insulation and is formed of a transparent material to minimize light loss. For example, at least one of the passivation 150 may be formed of Si02, SixOy, Si3N4, SixNy, SiOxNy, Al2O3, TiO2, or the like. Can be selected and formed.

Meanwhile, when the first electrode layer 170 has a predetermined pattern, the passivation 150 may be formed in a shape corresponding to the pattern of the first electrode layer 170.

4 to 9 are process charts showing the manufacturing method of the light emitting device shown in FIG.

Referring to FIG. 4, the light emitting structure 140 is formed on the support substrate 190.

The support substrate 190 may be formed of at least one of sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, Si, GaP, InP, Ge, but is not limited thereto.

The light emitting structure 140 may be formed on the support substrate 190. The light emitting structure 140 may be formed of a multilayer semiconductor, and may include at least a first semiconductor layer 124, an active layer 144 under the first semiconductor layer 142, and a second semiconductor layer 146 under the active layer 144. ) May be included.

The light emitting structure 140 may include metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), plasma chemical vapor deposition (PECVD), and molecular beam growth (MBE). Molecular Beam Epitaxy), Hydride Vapor Phase Epitaxy (HVPE), or the like, may be formed using, but is not limited thereto.

Referring to FIG. 5, an insulating layer 130 may be formed on a circumferential region of an upper surface of the light emitting structure 140, and a substrate 110 may be formed on the light emitting structure 140 and the insulating layer 130.

The insulating layer 130 may be formed by a deposition process and a photolithography process, but is not limited thereto.

The substrate 110 may be formed by a deposition process and a plating process, or may be bonded after being prepared as a separate sheet, but is not limited thereto.

Meanwhile, a reflective layer 120 may be formed under the substrate 110 to improve light extraction efficiency of the light emitting device 100. In addition, an ohmic layer 125 may be formed between the second semiconductor layer 146 and the support substrate 190.

5 and 6, the support substrate 190 may be removed. The support substrate 190 may be removed using at least one of a laser lift off (LLO) process and an etching process, but is not limited thereto.

On the other hand, after removing the support substrate 190, in order to polish the exposed surface of the first semiconductor layer 142 may be etched, such as ICP / RIE (Inductively Coupled Plasma / Reactive Ion Etch).

Referring to FIG. 7, an isolation etching may be performed on the light emitting structure 140 to divide the plurality of chips into individual chip units, and a passivation 150 may be formed on the side surface of the light emitting structure 140.

The isolation etching may be performed to expose the top surface of the insulating layer 130.

The passivation 150 may be formed by, for example, electron beam (E-beam) deposition or PECVD deposition.

The passivation 150 may be formed of a material having good light transmittance while having electrical insulation. For example, the passivation 150 may be formed of at least one of Si02, SixOy, Si3N4, SixNy, SiOxNy, Al2O3, and TiO2.

On the other hand, the passivation 150 is not limited to being formed on the side of the light emitting structure 140, it may be partially formed on the upper surface of the light emitting structure 140.

Referring to FIG. 8, the first electrode layer 170 may be formed to be in contact with the top surface of the light emitting structure 140 and to have at least a portion of the region disposed on the insulating layer 130. That is, the first electrode layer 170 may extend from an upper surface of the first semiconductor layer 142 and be disposed on the insulating layer 130 along the side surface of the passivation 150.

The material of the first electrode layer 170 may be electrically conductive, and may be a metal or a conductive nonmetal making ohmic contact with the first semiconductor layer 142. For example, the first electrode layer 170 may include Cu, Ti, Zn, Au, Ni, Pt, Ir, Rh, Ag, ITO, IZO (In-ZnO), GZO (Ga-ZnO), and AZO (Al-). ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrOx, RuOx, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO or ZnO have.

The first electrode layer 170 may be formed over the entire area of the light emitting structure 140 or may have a predetermined pattern, which is dependent on the design of the light emitting device 100 and the material of the first electrode layer 170. Can be determined.

Referring to FIG. 9, a protective cap layer 180 having the same pattern as the first electrode layer 170 may be disposed on the first electrode layer 170.

In this case, the protective cap layer 180 may be formed smaller than the pattern of the first electrode layer 170 to expose at least a portion of the first electrode layer 170 disposed on the insulating layer 130.

Here, the first electrode layer 170 exposed by the protective cap layer 180 may be bonded to the wire (W) to be connected to the external power source, the metal layer is in contact between the wire (W) and the first electrode layer 170 It may be formed, but is not limited thereto.

Meanwhile, although the embodiment has been described with reference to a vertical light emitting device, the present invention is not limited thereto and may be applied to a horizontal light emitting device.

In addition, at least one process in the process sequence illustrated in FIGS. 4 to 9 may be changed in order, but is not limited thereto.

The light emitting device 100 according to the embodiment may be mounted in a package, and a plurality of light emitting device packages on which the light emitting diodes are mounted are arranged on a substrate, and a light guide plate, a prism sheet, which is an optical member on an optical path of the light emitting device package, A diffusion sheet and the like can be arranged.

The light emitting device package, the substrate, and the optical member may function as a light unit. Another embodiment may be implemented as a display device, an indicator device, or an illumination system including the light emitting diode or light emitting device package described in the above embodiments, for example, the illumination system may include a lamp or a street lamp.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

In addition, the above description has been made with reference to the embodiments, which are merely exemplary and are not intended to limit the present invention, and those skilled in the art to which the present invention pertains are not exemplified above without departing from the essential characteristics of the embodiments. It will be appreciated that many variations and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to these modifications and applications will have to be construed as being included in the scope of the embodiments defined in the appended claims.

Claims (12)

Board;
A light emitting structure disposed on the substrate, the light emitting structure including a first semiconductor layer, a second semiconductor layer, and an active layer formed between the first and second semiconductor layers;
An insulating layer disposed on an upper surface of an outer circumferential portion of the substrate;
A first electrode layer disposed on the first semiconductor layer and extending along a side surface of the light emitting structure and disposed on the insulating layer;
Passivation disposed between the side surface of the light emitting structure and the first electrode layer; And
And a protective cap layer disposed on the first electrode layer. The method of claim 1, wherein the side surface of the light emitting structure,
Light emitting device having a slope. The method of claim 1, wherein the insulating layer,
A light emitting device for insulating the light emitting structure and the first electrode layer. The method of claim 1, wherein the first electrode layer,
A light emitting device comprising a conductive material in ohmic contact with the first semiconductor layer. The method of claim 4, wherein the first electrode layer,
Cu, Ti, Zn, Au, Ni, Pt, Ir, Rh, Ag, ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO Light-emitting device comprising at least one of (In-Ga ZnO), IrOx, RuOx, RuOx / ITO, Ni / IrOx / Au, Ni / IrOx / Au / ITO or ZnO. The method of claim 1, wherein the protective cap layer,
Light emitting device of the same material as the passivation. The method of claim 1, wherein the protective cap layer,
A light emitting device comprising at least one of Si0 ₂ , SixOy, Si ₃ N ₄ , SixNy, SiOxNy, Al ₂ O ₃ , TiO ₂ . The method of claim 1, wherein the protective cap layer,
At least a portion of the first electrode layer disposed on the insulating layer is exposed. The method of claim 1,
And a junction metal layer disposed on the insulating layer and disposed on the first electrode layer at least partially exposed. The method of claim 9, wherein the junction metal layer,
A light emitting device in contact with the protective cap layer. The method of claim 1,
A reflective layer disposed on the substrate; And
And an ohmic layer disposed between the reflective layer and the light emitting structure. The method of claim 1, wherein the substrate,
Light emitting device that is a conductive substrate.

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