KR102019751B1 - Light emitting device - Google Patents

Abstract

The light emitting device according to the embodiment includes a light emitting structure including a potential blocking layer, a first semiconductor layer on the potential blocking layer, an active layer on the first semiconductor layer, and a second semiconductor layer on the active layer, and the potential blocking layer Includes Al _x Ga _(1-x) N, and the composition ratio x of Al increases as the first semiconductor layer is adjacent to the first semiconductor layer.

Description

Light emitting device

The embodiment relates to a light emitting device.

As a representative example of a light emitting device, an LED (Light Emitting Diode) is a device that converts an electrical signal into a form of infrared rays, visible rays or light using characteristics of a compound semiconductor. It is used in automation equipment and the like, and the use area of LED is gradually increasing.

In general, miniaturized LEDs are made of a surface mount device type for direct mounting on a printed circuit board (PCB) board. Accordingly, LED lamps, which are used as display elements, are also being developed as surface mount device types. . Such a surface mounting element can replace a conventional simple lighting lamp, which is used as a lighting display for various colors, a character display and an image display.

As the usage area of the LED becomes wider as described above, the luminance required for electric light used for living, electric light for rescue signals, etc. is increased, and it is important to increase the luminance of the LED.

In addition, the electrode of the light emitting device should be excellent in adhesive strength and excellent electrical properties.

In addition, research is being conducted to improve the probability of recombination of electrons and holes in the active layer of the light emitting device.

There is a problem in that lattice mismatch of the semiconductor layer occurs due to different lattice constants between materials.

The embodiment provides a light emitting device that reduces strain generated between the first semiconductor layer and the active layer, improves the quality of the light emitting structure, and improves the light extraction efficiency.

The light emitting device according to the embodiment includes a light emitting structure including a potential blocking layer, a first semiconductor layer on the potential blocking layer, an active layer on the first semiconductor layer, and a second semiconductor layer on the active layer, and the potential blocking layer Includes Al _x Ga _(1-x) N, and the composition ratio x of Al increases as the first semiconductor layer is adjacent to the first semiconductor layer.

According to the embodiment, when the composition ratio x of the Al in the potential blocking layer is increased, the refractive index of the potential blocking layer is increased, so that the NFP (near-by-near-field image) in the vertical direction can be widened and the surface area of the light escape cone can be enlarged. . When the composition ratio x of Al is small, the lattice mismatch with the substrate becomes small, so that the potential blocking layer can be formed thick without problems of cracks or transitions.

Further, according to the embodiment, it is possible to block the potential while increasing the light extraction efficiency of the light emitting device.

If the potential blocking layer is formed thick, the potential is more effectively blocked, and the light generated in the active layer is not directed to the substrate, and there is an advantage in that it can be refracted to the outside of the light emitting device.

In addition, the strain relaxed buffer layer has an advantage of mitigating strain generated between the first semiconductor layer and the active layer due to the different lattice constant between the materials.

In addition, the embodiment does not rapidly change the strain in the strain mitigating layer, but the layer having tensile and compressive strain is first thinly alternately stacked and later alternately thickly, so that the strain is gradually changed. The strain between the active layer and the first semiconductor layer can be relaxed.

Further, in the embodiment, the first semiconductor layer is formed by first stacking layers having tensile and compressive strains alternately thinly and later laminating the same as the thickness of the barrier layer or the well layer, thereby creating an environment similar to the active layer in advance. And strain generated between the active layer and the active layer can be alleviated.

Further, the embodiment alleviates the lattice mismatch occurring in the semiconductor layer, and thus has the advantage of improving the quality of the semiconductor layer.

1 is a cross-sectional view showing a light emitting device according to the embodiment;
2 is an explanatory diagram showing a propagation path of light in a light emitting device according to a mounting example;
3 is an enlarged cross-sectional view of portion A of the light emitting device of FIG. 1;
4 is a sectional view showing a light emitting device according to another embodiment;
5 is a perspective view of a light emitting device package including a light emitting device according to the embodiment;
6 is a cross-sectional view of a light emitting device package including a light emitting device according to the embodiment;
7 is an exploded perspective view of a display device having a light emitting device according to the embodiment.
8 is a diagram illustrating a display device having a light emitting device according to an exemplary embodiment.
9 is an exploded perspective view of a lighting device having a light emitting device according to the embodiment.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, only the embodiments are to make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

The spatially relative terms " below ", " beneath ", " lower ", " above ", " upper " It may be used to easily describe the correlation of a device or components with other devices or components. Spatially relative terms are to be understood as terms that include different directions of the device in use or operation in addition to the directions shown in the figures. For example, when flipping a device shown in the figure, a device described as "below" or "beneath" of another device may be placed "above" of another device. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can also be oriented in other directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, “comprises” and / or “comprising” refers to the presence of one or more other components, steps, operations and / or elements. Or does not exclude additions.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. In addition, the terms defined in the commonly used dictionaries are not ideally or excessively interpreted unless they are specifically defined clearly.

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

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 constituting the light emitting device in the specification, if the reference point and the positional relationship with respect to the angle is not clearly mentioned, reference is made to related drawings.

1 is a cross-sectional view showing a light emitting device according to the embodiment, Figure 2 is an explanatory view showing the path of light in the light emitting device according to the embodiment, Figure 3 is an enlarged cross-sectional view of a portion A of the light emitting device of FIG.

Referring to FIG. 1, the light emitting device 100 according to the embodiment may be disposed on the first semiconductor layer 120 and the first semiconductor layer 120 to reduce strain generated in the semiconductor layer. 140, the light emitting structure 160 including the active layer 130 on the strain relaxed buffer layer 140 and the second semiconductor layer 150 on the active layer 130 may be included.

The potential blocking layer 117 may be further disposed below the light emitting structure 160.

Referring to FIG. 1, the light emitting device 100 may include a substrate 110 and a light emitting structure 160 disposed on the substrate 110. The light emitting structure 160 may include a first semiconductor layer 120, The strain relaxed buffer layer 140, the active layer 130, and the second semiconductor layer 150 may be included.

The substrate 110 may be formed of a material having a light transmitting property, for example, any one of sapphire (Al ₂ O ₃ ), GaN, ZnO, AlO, but is not limited thereto. In addition, the SiC support member may have a higher thermal conductivity than the sapphire (Al ₂ O ₃ ) support member. However, the refractive index of the substrate 110 may be smaller than the refractive index of the first semiconductor layer 120 for light extraction efficiency.

Meanwhile, a PSS (Patterned SubStrate) structure may be provided on the upper surface of the substrate 110 to increase light extraction efficiency. The support member 110 referred to herein may or may not have a PSS structure.

Meanwhile, a buffer layer 115 may be disposed on the substrate 110 to mitigate lattice mismatch between the substrate 110 and the first semiconductor layer 120 and to easily grow the semiconductor layer. The buffer layer 115 may be formed in a low temperature atmosphere, and may be formed of a material capable of alleviating the difference in lattice constant between the semiconductor layer and the support member. For example, a material such as GaN, InN, AlN, AlInN, InGaN, AlGaN, and InAlGaN may be selected, but is not limited thereto.

The buffer layer 115 may grow as a single crystal on the substrate 110, and the buffer layer 115 grown as the single crystal may improve crystallinity of the first semiconductor layer 120 growing on the buffer layer 115.

An undoped semiconductor layer (not shown) may be positioned on the buffer layer 115. Although the undoped semiconductor layer is not intentionally implanted with an n-type impurity, it is a nitride semiconductor layer that may have n-type conductivity. For example, the undoped semiconductor layer may be formed of Undoped-GaN.

The light emitting structure 160 including the first semiconductor layer 120, the strain relaxed buffer layer 140, the active layer 130, and the second semiconductor layer 150 may be formed on the undoped semiconductor layer.

The first semiconductor layer 120 may be positioned on the undoped semiconductor layer. The first semiconductor layer 120 may be implemented as an n-type semiconductor layer, and may provide electrons to the active layer 130. The first semiconductor layer 120 is, for example, 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 ≦ 1), for example For example, it may be selected from GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, and the like, and an n-type dopant such as Si, Ge, Sn, or the like may be doped.

The strain relaxed buffer layer 140 may be formed on the first semiconductor layer 120.

The strain relaxed buffer layer 140 may have a super lattice structure to alleviate strain generated in the light emitting structure 160.

That is, the strain relaxed buffer layer 140 relaxes the strain generated between the first semiconductor layer 120 and the active layer 130 due to different lattice constants between the materials.

The active layer 130 may be formed on the strain relaxed buffer layer 140. The active layer 130 may be formed of a single or multiple quantum well structure, a quantum-wire structure, a quantum dot structure, or the like using a compound semiconductor material of a group III-V group element.

When the active layer 130 is formed of a quantum well structure, for example, a well layer having a composition formula of In _x Al _y Ga _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1); It may have a single or multiple quantum well structure having a barrier layer having a composition formula of In _a Al _b Ga _1-ab N (0 ≦ a ≦ ₁ , 0 ≦ b ≦ ₁ , 0 ≦ a + b ≦ 1). The well layer may be formed of a material having a band gap smaller than the band gap of the barrier layer.

A conductive clad layer (not shown) may be formed on or under the active layer 130. The conductive cladding layer (not shown) may be formed of an AlGaN-based semiconductor, and may have a band gap larger than that of the active layer 130.

The second semiconductor layer 150 may be implemented as a p-type semiconductor layer to inject holes into the active layer 130. The second semiconductor layer 150 is, for example, 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 ≦ 1), for example For example, it may be selected from GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, and the like, and p-type dopants such as Mg, Zn, Ca, Sr, and Ba may be doped.

Meanwhile, a current blocking layer (not shown) may be formed between the active layer 130 and the second semiconductor layer 150, and electrons injected into the active layer 130 from the first semiconductor layer 120 when high current is applied. Does not recombine in the active layer 130 and prevents the phenomenon of flowing into the second semiconductor layer 150. The current blocking layer has a larger bandgap than the active layer 130, so that electrons injected from the first semiconductor layer 130 are injected into the second semiconductor layer 150 without recombination in the active layer 130. It can prevent. Accordingly, the probability of recombination of electrons and holes in the active layer 140 may be increased and leakage current may be prevented.

The current blocking layer may have a band gap larger than that of the barrier layer included in the active layer 130, and may be formed of a semiconductor layer including Al, such as p-type AlGaN, but is not limited thereto.

The first semiconductor layer 120, the active layer 130, and the second semiconductor layer 150 may be, for example, metal organic chemical vapor deposition (MOCVD) or chemical vapor deposition (CVD). ), Plasma-Enhanced Chemical Vapor Deposition (PECVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), and Sputtering It may be formed by, but is not limited thereto.

In addition, the doping concentrations of the conductive dopants in the first semiconductor layer 120 and the second semiconductor layer 150 may be uniformly or non-uniformly formed. That is, the plurality of semiconductor layers may be formed to have various doping concentration distributions, but is not limited thereto.

In addition, the first semiconductor layer 120 may be implemented as a p-type semiconductor layer, the second semiconductor layer 150 may be implemented as an n-type semiconductor layer, and the n-type or p-type semiconductor is formed on the second semiconductor layer 150. A third semiconductor layer (not shown) including a layer may be formed. Accordingly, the light emitting device 100 may have at least one of np, pn, npn, and pnp junction structures.

Meanwhile, a portion of the active layer 130 and the second semiconductor layer 150 may be removed to expose a portion of the first semiconductor layer 120, and the first electrode 174 may be disposed on the exposed first semiconductor layer 120. This can be formed. That is, the first semiconductor layer 120 includes an upper surface facing the active layer 130 and a lower surface facing the substrate 110, and the upper surface includes an area at least one region is exposed, and the first electrode 174 is an upper surface. It can be placed on the exposed area of the.

Meanwhile, a method of exposing a part of the first semiconductor layer 120 may use a predetermined etching method, but is not limited thereto. In addition, the etching method may be a wet etching, dry etching method.

The transparent electrode layer 180 may be formed on the second semiconductor layer 150. The transparent electrode layer 170 plays a role of uniformly spreading current in the second semiconductor layer 150.

The transparent electrode layer 180 may be formed of, for example, ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrOx. , RuOx, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO may include, but are not limited to.

In addition, a second electrode 172 may be formed on the transparent electrode layer 180.

Meanwhile, the first and second electrodes 172 and 174 may be conductive materials such as In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, W It may include a metal selected from Ti, Ag, Cr, Mo, Nb, Al, Ni, Cu, and Ti, or may include an alloy thereof, may be formed in a single layer or multiple layers, but is not limited thereto. .

The dislocation blocking layer blocks dislocations coming up from the substrate 110 and / or the buffer layer 115 and eliminates lattice mismatch with the substrate 110 or / and the buffer layer 115. In particular, the dislocations intensively generated in the pattern portion of the substrate 110 serve to flatten or terminate the rising in the direction of the light emitting structure 160. A semiconductor material of Al _x Ga _(1-x) N is included, and the composition ratio x of Al may increase as it is adjacent to the first semiconductor layer 120. That is, the composition ratio x of Al under the potential blocking layer 117 may be smaller than the composition ratio x of Al above the potential blocking layer 117.

As the composition ratio x of Al in Al _x Ga _(1-x) N increases, the refractive index of the AlGaN layer increases, so that the NFP in the vertical direction is widened and the surface area of the light escape cone is enlarged. Can be. In addition, when the composition ratio x of Al decreases, the lattice mismatch with the substrate 110 becomes small, so that the potential blocking layer 117 can be formed thick without problems of cracks or transitions.

If the potential blocking layer 117 is formed thick, the potential is blocked more effectively, and light generated in the active layer 130 may be directed to the outside of the light emitting device without directing the light to the substrate 110.

In other words, as shown in FIG. 2, when the potential blocking layer 117 is formed thick and the composition ratio x of Al of the potential blocking layer 117 adjacent to the first semiconductor layer 120 is high and the refractive index is high, the active layer 130 is formed. ) Does not direct light generated to the substrate 110 (P1), but may be guided (refractive) to the outside of the light emitting device (P2). Of course, the lattice mismatch with the substrate 110 and the potential rising from the substrate 110 may be blocked.

The thickness of the potential blocking layer 117 may have a sufficient thickness to sufficiently block the potential rising to the substrate 110 and to deflect light generated in the active layer 130 to the outside. For example, the thickness of the potential blocking layer 117 is preferably 100 nm to 400 nm.

The potential blocking layer 117 may have a super lattice structure.

The composition ratio x of Al of the potential blocking layer 117 may increase in the direction of the first semiconductor layer 120 from the substrate 110. At this time, the composition ratio x of Al of the potential blocking layer 117 may change linearly or nonlinearly.

Referring to FIG. 3, the strain mitigating layer 140 may include at least two subgroups. In FIG. 3, three subgroups 141, 143, and 145 are illustrated, but the present invention is not limited thereto. Here, the subgroups 141, 143, and 145 that are adjacent to the first semiconductor layer 120 are defined as the first subgroup 141, and the second subgroup 143 and the third subgroup 145 in the direction of the active layer 130 are defined. It is defined as.

The number of subgroups 141, 143, and 145 is not limited, but may be 2-8.

Meanwhile, the subgroups 141, 143, and 145 may be formed by alternately stacking at least two pairs of InGaN layers and GaN layers. More preferably, 3 to 8 pairs may be alternately stacked.

In addition, the thickness of each of the subgroups 141, 143, and 145 may be thicker as it is adjacent to the active layer 130. As the thickness of each of the subgroups 141, 143, and 145 increases as the thickness of the active layer 130 increases, the thickness of each of the subgroups 141, 143, and 145 becomes similar to that of the active layer 130. ), The lattice constant of the strain relaxed buffer layer 140 may be similar to that of the active layer 130, and the strain may be reduced.

Arrangements where the thickness of each subgroup 141, 143, 145 becomes thicker as the active layer 130 is adjacent may have various arrangements.

For example, the thickness of the second subgroup 143 may be thicker than that of the first subgroup 141, and the thickness of the third subgroup 145 may be thicker than that of the second subgroup 143.

The number of InGaN layers 141A, 143A, 145A and GaN layers 141B, 143B, 145B of each subgroup 141, 143, 145 is the same. For example, the number of InGaN layers 141A of the first subgroup 141 and the number of InGaN layers 143A and 145A of the second subgroup 143 and the third subgroup 145 are the same. The number of GaN layers 141B of the first subgroup 141 and the number of GaN layers 143B and 145B of the second subgroup 143 and the third subgroup 145 are the same. Further, the thicknesses of the InGaN layers 141A, 143A, and 145A and the GaN layers 141B, 143B, and 145B are preferably arranged within the subgroups 141, 143, and 145. That is, if the subgroups 141, 143, and 145 are different, the thicknesses of the InGaN layers 141A, 143A, and 145A and the GaN layers 141B, 143B, and 145B may be different.

The thicknesses of the InGaN layers 141A, 143A, and 145A and the GaN layers 141B, 143B, and 145B may be 1 nm to 1 μm, and the thicknesses of the GaN layers 141B, 143B, and 145B may be InGaN layers 141A, 143A, and 145A. May be greater than or equal to the thickness.

Another example of the arrangement in which the thickness of each subgroup 141, 143, 145 becomes thicker as the active layer 130 is adjacent is as follows. However, the above description is assumed.

For example, the thickness of the InGaN layer in the subgroup adjacent to the active layer 130 may be thicker than the thickness of the InGaN layer in the subgroup adjacent to the first semiconductor layer 120. That is, the thickness of the InGaN 143A layer in the second subgroup 143 may be thicker than the thickness of the InGaN layer 141A in the first subgroup 141 and the InGaN layer 145A in the third subgroup 145. ) May be thicker than the thickness of the InGaN layer 143A in the second subgroup 143. In other words, the thickness of the InGaN layers 141A, 143A, and 145A may be thicker as the subgroups 141, 143, and 145 are adjacent to the active layer 130. In this case, the thickness of the GaN layers 141B, 143B, and 145B of each of the subgroups 141, 143, and 145 is constant, or the thicker the GaN layers 141B, 143B, and 145B of the subgroups 141, 143, and 145 adjacent to the active layer 130 are formed. Can be.

In this case, the thickness limitation of the InGaN layers 141A, 143A, and 145A is preferably the thickness of the barrier layer or the well layer of the active layer 130. That is, the thickness of the InGaN layer of the third subgroup 145 adjacent to the active layer 130 may be the same as the barrier layer or the well layer of the active layer 130. That is, the thicknesses of the InGaN layers 141A, 143A, and 145A are initially thinly disposed, and eventually, the thicknesses of the barrier layer and the well layer of the active layer 130 are similarly disposed between the first semiconductor layer 120 and the active layer 130. It can alleviate strain occurring in the

As another example, the thickness of the GaN layer in the subgroup adjacent to the active layer 130 may be thicker than the thickness of the GaN layer in the subgroup adjacent to the first semiconductor layer 120. That is, the thickness of the GaN 143B layer in the second subgroup 143 may be thicker than the thickness of the GaN layer 141B in the first subgroup 141, and the GaN layer 145B in the third subgroup 145. ) May be thicker than the thickness of the GaN layer 143B in the second subgroup 143. In other words, the thickness of the GaN layers 141B, 143B, and 145B may be thicker as the subgroups 141, 143, and 145 are adjacent to the active layer 130. In this case, the thicknesses of the InGaN layers 141A, 143A, and 145A of the subgroups 141, 143, and 145 are constant, or the thicker the InGaN layers 141A, 143A, and 145A of the subgroups 141, 143, and 145 adjacent to the active layer 130 are formed. Can be.

In this case, the thickness limitation of the GaN layers 141B, 143B, and 145B is preferably the thickness of the barrier layer or the well layer of the active layer 130. That is, the thickness of the GaN layer of the third subgroup 145 adjacent to the active layer 130 may be the same as the barrier layer or the well layer of the active layer 130. That is, the thicknesses of the GaN layers 141B, 143B, and 145B are initially thinly disposed, and finally, the thicknesses of the GaN layers 141B, 143B, and 145B are similar to the thicknesses of the barrier layer and the well layer of the active layer 130, and thus between the first semiconductor layer 120 and the active layer 130. It can alleviate strain occurring in the

Here, the meaning of the same does not mean the exact same of the mathematical meaning, but means the same in the range including an error.

When the thicknesses of the InGaN and GaN layers of the subgroups 141, 143, and 145 increase as adjacent to the active layer 130, and become similar to those of the barrier layer or the well layer of the active layer 130, the first semiconductor layer 120 and the active layer Strains occurring between 130 are alleviated.

The embodiment does not rapidly change the strain in the strain mitigating layer 140, but first the layers having tensile and compressive strains are alternately thinly laminated and later alternately thickly, so that the strain is gradually changed. Therefore, the strain between the active layer 130 and the first semiconductor layer 120 can be alleviated.

In addition, the embodiment of the present invention creates an environment similar to the active layer 130 in advance by stacking layers having tensile and compressive strains alternately thinly at first and later laminating the same as the thickness of the barrier layer or well layer. The strain generated between the semiconductor layer 120 and the active layer 130 can be alleviated.

In In ratios of the InGaN layers 141A, 143A, and 145A may be higher in the InGaN layers 141A, 143A, and 145A of the subgroups 141, 143, and 145 adjacent to the first semiconductor layer 120. Here, In content rate means the molar ratio or mass ratio of In in InGaN.

3 is a cross-sectional view showing a light emitting device according to another embodiment.

Referring to FIG. 3, the light emitting device 200 according to the embodiment includes a support member 210, a first electrode layer 215 disposed on the support member 210, and a second semiconductor layer on the first electrode layer 215. (250), the active layer 230 on the second semiconductor layer 250, the strain relaxed buffer layer 240 on the active layer 230, the first semiconductor layer 220 on the strain relaxed buffer layer 240, and the potential blocking layer ( 217 and the second electrode layer 282.

The support member 210 may be formed using a material having excellent thermal conductivity and may be formed of a conductive material, and may be formed using a metal material or a conductive ceramic. The support member 210 may be formed in a single layer, or may be formed in a double structure or multiple structures.

That is, the support member 210 may be formed of any one selected from a metal, for example, Au, Ni, W, Mo, Cu, Al, Ta, Ag, Pt, or Cr, or may be formed of two or more alloys. The above materials can be laminated and formed. In addition, the support member 210 may be implemented as a carrier wafer such as Si, Ge, GaAs, ZnO, SiC, SiGe, GaN, Ga ₂ O ₃ .

The support member 210 may facilitate the emission of heat generated from the light emitting device 200 to improve the thermal stability of the light emitting device 200.

Meanwhile, a first electrode layer 215 may be formed on the support member 210, and the first electrode layer 215 may be an ohmic layer (not shown), a reflective layer (not shown), or a bonding layer. It may include at least one layer (bonding layer) (not shown). For example, the first electrode layer 215 may be a structure of an ohmic layer / reflective layer / bonding layer, a stacked structure of an ohmic layer / reflective layer, or a structure of a reflective layer (including ohmic) / bonding layer, but is not limited thereto. For example, the first electrode layer 215 may have a form in which a reflective layer and an ohmic layer are sequentially stacked on the insulating layer.

The reflective layer (not shown) may be disposed between the ohmic layer (not shown) and the insulating layer (not shown), and have excellent reflective properties, for example, Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg , Zn, Pt, Au, Hf, or a combination of these materials, or a combination of these materials or IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, to form a multi-layer using a transparent conductive material such as Can be. In addition, the reflective layer (not shown) may be laminated with IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni, or the like. In addition, when the reflective layer (not shown) is formed of a material in ohmic contact with the light emitting structure 260 (eg, the second semiconductor layer 250), the ohmic layer (not shown) may not be separately formed, and the like It doesn't.

The ohmic layer (not shown) is in ohmic contact with the bottom surface of the light emitting structure 260, and may be formed in a layer or a plurality of patterns. The ohmic layer (not shown) may selectively use a light-transmitting electrode layer and a metal. For example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), and indium aluminum zinc oxide (AZO) ), Indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrO _x , RuO _x , RuO _x / ITO, One or more of Ni, Ag, Ni / IrO _x / Au, and Ni / IrO _x / Au / ITO may be used to implement a single layer or multiple layers. The ohmic layer (not shown) is for smoothly injecting a carrier into the second semiconductor layer 250 and is not necessarily formed.

In addition, the first electrode layer 215 may include a bonding layer (not shown), wherein the bonding layer (not shown) may be a barrier metal or a bonding metal, eg, Ti, Au, Sn, or Ni. It may include, but is not limited to, at least one of Cr, Ga, In, Bi, Cu, Ag, or Ta.

The light emitting structure 260 may include at least a first semiconductor layer 220, an active layer 230, and a second semiconductor layer 250, between the first semiconductor layer 220 and the second semiconductor layer 250. The active layer 230 may be formed in the configuration shown.

The second semiconductor layer 250 may be formed on the first electrode layer 215. The second semiconductor layer 250 may be implemented as a p-type semiconductor layer doped with a p-type dopant. The p-type semiconductor layer is 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 ≦ 1), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN and the like may be selected, and p-type dopants such as Mg, Zn, Ca, Sr, and Ba may be doped.

 The active layer 230 may be formed on the second semiconductor layer 250. The active layer 230 may be formed of a single or multiple quantum well structure, a quantum-wire structure, a quantum dot structure, or the like using a compound semiconductor material of a group 3 to 5 element.

If the active layer 230 is formed of a quantum well structure, for example, a well layer having a composition formula of In _x Al _y Ga _1-xy N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) It may have a single or quantum well structure having a barrier layer having a composition formula of In _a Al _b Ga _1-ab N (0 ≦ a ≦ ₁ , 0 ≦ b ≦ ₁ , 0 ≦ a + b ≦ 1). The well layer may be formed of a material having a band gap smaller than the band gap of the barrier layer.

A conductive clad layer (not shown) may be formed on or under the active layer 230. The conductive clad layer (not shown) may be formed of an AlGaN-based semiconductor, and may have a band gap larger than that of the active layer 230.

The strain relaxed buffer layer 240 is formed on the active layer 230. The structure of the strain relaxed buffer layer 240 is the same as described with reference to FIG. 3, and unlike FIG. 3, only the upper and lower parts are changed.

The first semiconductor layer 220 may be formed on the strain relaxed buffer layer 240. The first semiconductor layer 220 may be implemented as an n-type semiconductor layer, the n-type semiconductor layer is, for example, In _x Al _y Ga _1-xy N (0≤x≤1, 0≤y≤1, 0≤x a semiconductor material having a compositional formula of + y ≦ 1), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, and the like, and for example, n, such as Si, Ge, Sn, Se, Te, etc. Type dopants may be doped.

 A second electrode layer 282 electrically connected to the first semiconductor layer 220 may be formed on the first semiconductor layer 220, and the second electrode layer 282 may include at least one pad or an electrode having a predetermined pattern. It may include. The second electrode layer 282 may be disposed in the center region, the outer region, or the corner region of the upper surface of the first semiconductor layer 220, but is not limited thereto. The second electrode layer 282 may be disposed in an area other than the first semiconductor layer 220, but is not limited thereto.

Description of the potential blocking layer 217 has been described with reference to FIG. 1.

The second electrode layer 282 is a conductive material, such as In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, W, Ti, Ag, Cr It may be formed in a single layer or multiple layers using a metal or an alloy selected from among Mo, Nb, Al, Ni, Cu, and WTi.

The light extraction structure 284 may be formed on the light emitting structure 260.

The light extracting structure 270 may be formed on the upper surface of the first semiconductor layer 220, or may be formed on the light transmissive electrode layer (not shown) after the light transmissive electrode layer (not shown) is formed on the light emitting structure 260. It is not limited thereto.

The light extracting structure 284 may be formed in a part or the entire area of the light transmissive electrode layer (not shown), or the upper surface of the first semiconductor layer 220. The light extraction structure 284 may be formed by performing etching on at least one region of the transparent electrode layer (not shown) or the upper surface of the first semiconductor layer 220, but is not limited thereto. The etching process may include a wet or dry etching process, and as the etching process is performed, an upper surface of the light transmissive electrode layer (not shown) or an upper surface of the first semiconductor layer 220 may form a light extraction structure 284. Roughness may be included. Roughness may be irregularly formed in a random size, but is not limited thereto. The roughness is an uneven upper surface and may include at least one of a texture pattern, an uneven pattern, and an uneven pattern.

Roughness may be formed so that the side cross section has a variety of shapes, such as a cylinder, a polygonal pillar, a cone, a polygonal pyramid, a truncated cone, a polygonal pyramid, preferably comprises a horn shape.

The light extracting structure 284 may be formed by a method such as photo electrochemical (PEC), but is not limited thereto. As the light extracting structure 284 is formed on the light transmissive electrode layer (not shown) or on the upper surface of the first semiconductor layer 220, the light generated from the active layer 230 is transmitted to the light transmissive electrode layer (not shown) or the first semiconductor layer. Since total reflection from the upper surface of the 220 may be prevented from being resorbed or scattered, it may contribute to the improvement of light extraction efficiency of the light emitting device 200.

Passivation 290 may be formed on side and upper regions of the light emitting structure 260, and passivation 290 may be formed of an insulating material.

5 is a perspective view showing a light emitting device package including a light emitting device according to the embodiment, Figure 6 is a cross-sectional view showing a light emitting device package including a light emitting device according to the embodiment.

5 and 6, the light emitting device package 500 includes a body 510 having a cavity 520, first and second lead frames 540 and 550 mounted on the body 510, and a first one. And a light emitting device 530 electrically connected to the second lead frames 540 and 550, and an encapsulant (not shown) filled in the cavity 520 to cover the light emitting device 530.

The body 510 is made of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), photosensitive glass (PSG), polyamide 9T (PA9T) ), Neo geotactic polystyrene (SPS), a metal material, sapphire (Al ₂ O ₃ ), beryllium oxide (BeO), may be formed of at least one of a printed circuit board (PCB, Printed Circuit Board). The body 510 may be formed by injection molding, etching, or the like, but is not limited thereto.

An inner surface of the body 510 may be formed with an inclined surface. The angle of reflection of the light emitted from the light emitting device 530 may vary according to the angle of the inclined surface, thereby adjusting the directivity angle of the light emitted to the outside.

As the directivity of the light decreases, the concentration of light emitted from the light emitting device 530 to the outside increases. On the contrary, the greater the directivity of the light, the less the concentration of light emitted from the light emitting device 530 to the outside.

On the other hand, the shape of the cavity 520 formed on the body 510 as viewed from above may be circular, rectangular, polygonal, elliptical, or the like, and may have a curved edge, but is not limited thereto.

The light emitting device 530 is mounted on the first lead frame 540 and may be, for example, a light emitting device emitting light of red, green, blue, white, or UV (ultraviolet) light emitting device emitting ultraviolet light. But it is not limited thereto. In addition, one or more light emitting devices 530 may be mounted.

In addition, the light emitting device 530 may be a horizontal type in which all of its electrical terminals are formed on an upper surface, or a vertical type or flip chip formed on an upper and a lower surface. Applicable

An encapsulant (not shown) may be filled in the cavity 520 to cover the light emitting device 530.

The encapsulant (not shown) may be formed of silicon, epoxy, and other resin materials, and may be formed by filling the cavity 520 and then UV or heat curing the same.

In addition, the encapsulant (not shown) may include a phosphor, and the phosphor may be selected from a wavelength of light emitted from the light emitting device 530 so that the light emitting device package 500 may realize white light.

The phosphor is one of a blue light emitting phosphor, a blue green light emitting phosphor, a green light emitting phosphor, a yellow green light emitting phosphor, a yellow light emitting phosphor, a yellow red light emitting phosphor, an orange light emitting phosphor, and a red light emitting phosphor according to a wavelength of light emitted from the light emitting element 530. Can be applied.

That is, the phosphor may be excited by light having the first light emitted from the light emitting device 530 to generate the second light. For example, when the light emitting element 530 is a blue light emitting diode and the phosphor is a yellow phosphor, the yellow phosphor may be excited by blue light to emit yellow light, and the blue light and blue light generated by the blue light emitting diode As the generated yellow light is mixed, the light emitting device package 500 may provide white light.

Similarly, when the light emitting element 530 is a green light emitting diode, a magenta phosphor or a mixture of blue and red phosphors is mixed. When the light emitting element 530 is a red light emitting diode, a cyan phosphor or a blue and green phosphor is used. For example,

Such phosphor may be a known phosphor such as YAG, TAG, sulfide, silicate, aluminate, nitride, carbide, nitridosilicate, borate, fluoride or phosphate.

The first and second lead frames 540 and 550 are made of a metal material, for example, titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chromium (Cr), and tantalum (Ta). , Platinum (Pt), tin (Sn), silver (Ag), phosphorus (P), aluminum (Al), indium (In), palladium (Pd), cobalt (Co), silicon (Si), germanium (Ge) It may include one or more materials or alloys of hafnium (Hf), ruthenium (Ru), iron (Fe). In addition, the first and second lead frames 540 and 550 may be formed to have a single layer or a multilayer structure, but the embodiment is not limited thereto.

The first second lead frames 540 and 550 are spaced apart from each other and electrically separated from each other. The light emitting device 530 is mounted on the first and second lead frames 540 and 550, and the first and second lead frames 540 and 550 are in direct contact with the light emitting device 530 or a soldering member (not shown). May be electrically connected through a material having conductivity such as C). In addition, the light emitting device 530 may be electrically connected to the first and second lead frames 540 and 550 through wire bonding, but is not limited thereto. Therefore, when power is connected to the first and second lead frames 540 and 550, power may be applied to the light emitting device 530. Meanwhile, several lead frames (not shown) may be mounted in the body 510, and each lead frame (not shown) may be electrically connected to the light emitting device 530, but is not limited thereto.

The light emitting device according to the embodiment may be applied to a lighting device. The lighting system includes a structure in which a plurality of light emitting elements are arranged, and includes a display device as shown in FIGS. 7 and 8 and a lighting device as shown in FIG. have.

7 is an exploded perspective view of a display device having a light emitting device according to the embodiment.

Referring to FIG. 7, the display device 1000 according to the embodiment includes a light guide plate 1041, a light source module 1031 that provides light to the light guide plate 1041, and a reflective member 1022 under the light guide plate 1041. ), An optical sheet 1051 on the light guide plate 1041, a display panel 1061, a light guide plate 1041, a light source module 1031, and a reflective member 1022 on the optical sheet 1051. The bottom cover 1011 may be included, but is not limited thereto.

The bottom cover 1011, the reflective sheet 1022, the light guide plate 1041, and the optical sheet 1051 may be defined as a light unit 1050.

The light guide plate 1041 diffuses light to serve as a surface light source. The light guide plate 1041 is made of a transparent material, for example, acrylic resin-based, such as polymethylmethacrylate (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin copolymer (COC), and polyethylene naphtha late (PEN) It may include one of the resins.

The light source module 1031 provides light to at least one side of the light guide plate 1041, and ultimately serves as a light source of the display device.

The light source module 1031 may include at least one, and may provide light directly or indirectly at one side of the light guide plate 1041. The light source module 1031 may include a substrate 1033 and a light emitting device 1035 according to the embodiment disclosed above, and the light emitting device 1035 may be arranged on the substrate 1033 at predetermined intervals. .

The substrate 1033 may be a printed circuit board (PCB) including a circuit pattern (not shown). However, the substrate 1033 may include not only a general PCB but also a metal core PCB (MCPCB, Metal Core PCB), a flexible PCB (FPCB, Flexible PCB) and the like, but is not limited thereto. When the light emitting device 1035 is mounted on the side surface of the bottom cover 1011 or the heat dissipation plate, the substrate 1033 may be removed. Here, a part of the heat dissipation plate may contact the upper surface of the bottom cover 1011.

The light emitting devices 1035 may be mounted on the substrate 1033 such that an emission surface from which light is emitted is spaced apart from the light guide plate 1041 by a predetermined distance, but is not limited thereto. The light emitting device 1035 may directly or indirectly provide light to a light incident part, which is one side of the light guide plate 1041, but is not limited thereto.

The reflective member 1022 may be disposed under the light guide plate 1041. The reflective member 1022 may improve the luminance of the light unit 1050 by reflecting light incident to the lower surface of the light guide plate 1041 and pointing upward. The reflective member 1022 may be formed of, for example, PET, PC, or PVC resin, but is not limited thereto. The reflective member 1022 may be an upper surface of the bottom cover 1011, but is not limited thereto.

The bottom cover 1011 may accommodate the light guide plate 1041, the light source module 1031, the reflective member 1022, and the like. To this end, the bottom cover 1011 may be provided with an accommodating part 1012 having a box shape having an upper surface opened thereto, but is not limited thereto. The bottom cover 1011 may be combined with the top cover, but is not limited thereto.

The bottom cover 1011 may be formed of a metal material or a resin material, and may be manufactured using a process such as press molding or extrusion molding. In addition, the bottom cover 1011 may include a metal or non-metal material having good thermal conductivity, but is not limited thereto.

The display panel 1061 is, for example, an LCD panel, and includes a first and second substrates of transparent materials facing each other, and a liquid crystal layer interposed between the first and second substrates. A polarizer may be attached to at least one surface of the display panel 1061, but the polarizer is not limited thereto. The display panel 1061 displays information by light passing through the optical sheet 1051. The display device 1000 may be applied to various portable terminals, monitors of notebook computers, monitors of laptop computers, televisions, and the like.

The optical sheet 1051 is disposed between the display panel 1061 and the light guide plate 1041 and includes at least one light transmissive sheet. The optical sheet 1051 may include at least one of a sheet such as, for example, a diffusion sheet, a horizontal and vertical prism sheet, and a brightness enhancement sheet. The diffusion sheet diffuses the incident light, the horizontal and / or vertical prism sheet focuses the incident light into the display area, and the brightness enhancement sheet reuses the lost light to improve the brightness. In addition, a protective sheet may be disposed on the display panel 1061, but is not limited thereto.

Here, the light guide plate 1041 and the optical sheet 1051 may be included as an optical member on the optical path of the light source module 1031, but are not limited thereto.

8 is a diagram illustrating a display device having a light emitting device according to an exemplary embodiment.

Referring to FIG. 8, the display device 1100 includes a bottom cover 1152, a substrate 1120 on which the light emitting device 1124 disclosed above is arranged, an optical member 1154, and a display panel 1155.

The substrate 1120 and the light emitting device 1124 may be defined as a light source module 1160. The bottom cover 1152, the at least one light source module 1160, and the optical member 1154 may be defined as a light unit 1150. The bottom cover 1152 may include an accommodating part 1153, but is not limited thereto. The light source module 1160 includes a substrate 1120 and a plurality of light emitting devices 1124 arranged on the substrate 1120.

Here, the optical member 1154 may include at least one of a lens, a light guide plate, a diffusion sheet, horizontal and vertical prism sheets, and a brightness enhancement sheet. The light guide plate may be made of a PC material or a polymethyl methacrylate (PMMA) material, and the light guide plate may be removed. The diffusion sheet diffuses the incident light, the horizontal and vertical prism sheets focus the incident light onto the display area, and the brightness enhancement sheet reuses the lost light to improve the brightness.

The optical member 1154 is disposed on the light source module 1160 and performs surface light, or diffuses, condenses, or the like the light emitted from the light source module 1160.

9 is an exploded perspective view of a lighting device having a light emitting device according to the embodiment.

Referring to FIG. 9, the lighting apparatus according to the embodiment may include a cover 2100, a light source module 2200, a radiator 2400, a power supply 2600, an inner case 2700, and a socket 2800. Can be. In addition, the lighting apparatus according to the embodiment may further include any one or more of the member 2300 and the holder 2500. The light source module 2200 may include a light emitting device according to an embodiment.

For example, the cover 2100 may have a shape of a bulb or hemisphere, may be hollow, and may be provided in an open shape. The cover 2100 may be optically coupled to the light source module 2200. For example, the cover 2100 may diffuse, scatter or excite the light provided from the light source module 2200. The cover 2100 may be a kind of optical member. The cover 2100 may be coupled to the heat sink 2400. The cover 2100 may have a coupling part coupled to the heat sink 2400.

An inner surface of the cover 2100 may be coated with a milky paint. The milky paint may include a diffuser to diffuse light. The surface roughness of the inner surface of the cover 2100 may be greater than the surface roughness of the outer surface of the cover 2100. This is for the light from the light source module 2200 to be sufficiently scattered and diffused to be emitted to the outside.

The cover 2100 may be made of glass, plastic, polypropylene (PP), polyethylene (PE), polycarbonate (PC), or the like. Here, polycarbonate is excellent in light resistance, heat resistance, and strength. The cover 2100 may be transparent and opaque so that the light source module 2200 is visible from the outside. The cover 2100 may be formed through blow molding.

The light source module 2200 may be disposed on one surface of the heat sink 2400. Thus, heat from the light source module 2200 is conducted to the heat sink 2400. The light source module 2200 may include a light emitting element 2210, a connection plate 2230, and a connector 2250.

The member 2300 is disposed on an upper surface of the heat sink 2400 and has a plurality of light emitting elements 2210 and guide grooves 2310 into which the connector 2250 is inserted. The guide groove 2310 corresponds to the substrate and the connector 2250 of the light emitting element 2210.

The surface of the member 2300 may be coated or coated with a light reflective material. For example, the surface of the member 2300 may be coated or coated with a white paint. The member 2300 is reflected on the inner surface of the cover 2100 to reflect the light returned to the light source module 2200 side again toward the cover 2100. Therefore, it is possible to improve the light efficiency of the lighting apparatus according to the embodiment.

The member 2300 may be made of an insulating material, for example. The connection plate 2230 of the light source module 2200 may include an electrically conductive material. Therefore, electrical contact may be made between the radiator 2400 and the connection plate 2230. The member 2300 may be formed of an insulating material to block an electrical short between the connection plate 2230 and the radiator 2400. The radiator 2400 receives heat from the light source module 2200 and heat from the power supply unit 2600 to radiate heat.

The holder 2500 may block the accommodating groove 2719 of the insulating portion 2710 of the inner case 2700. Therefore, the power supply unit 2600 accommodated in the insulating unit 2710 of the inner case 2700 is sealed. The holder 2500 has a guide protrusion 2510. The guide protrusion 2510 may include a hole through which the protrusion 2610 of the power supply unit 2600 passes.

The power supply unit 2600 processes or converts an electrical signal provided from the outside to provide the light source module 2200. The power supply unit 2600 is accommodated in the accommodating groove 2725 of the inner case 2700, and is sealed in the inner case 2700 by the holder 2500.

The power supply unit 2600 may include a protrusion 2610, a guide unit 2630, a base 2650, and a protrusion 2670.

The guide part 2630 has a shape protruding outward from one side of the base 2650. The guide part 2630 may be inserted into the holder 2500. A plurality of parts may be disposed on one surface of the base 2650. The plurality of components may include, for example, a DC converter for converting AC power provided from an external power source into DC power, a driving chip for controlling the driving of the light source module 2200, and an ESD for protecting the light source module 2200. (ElectroStatic discharge) protection element and the like, but may not be limited thereto.

The protrusion 2670 has a shape protruding to the outside from the other side of the base 2650. The protrusion 2670 is inserted into the connection part 2750 of the inner case 2700 and receives an electrical signal from the outside. For example, the protrusion 2670 may be provided to be the same as or smaller than the width of the connection portion 2750 of the inner case 2700. Each end of the “+ wire” and the “− wire” may be electrically connected to the protrusion 2670, and the other end of the “+ wire” and the “− wire” may be electrically connected to the socket 2800.

The inner case 2700 may include a molding unit together with the power supply unit 2600 therein. The molding part is a part where the molding liquid is hardened, so that the power supply part 2600 can be fixed inside the inner case 2700.

In addition, the above description has been made with reference to the embodiment, which is merely an example, and is not intended to limit the present invention. Many variations and applications are available. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

Claims (19)

Potential blocking layer;
A light emitting structure including a first semiconductor layer on the potential blocking layer, an active layer on the first semiconductor layer, and a second semiconductor layer on the active layer,
The potential blocking layer,
Al _x Ga _(1-x) N,
The composition ratio x of the Al increases as the adjacent to the first semiconductor layer,
The potential blocking layer has a thickness of 100nm to 400nm,
Further comprising a strain mitigating layer between the first semiconductor layer and the active layer to mitigate strain generated in the semiconductor layer,
The strain mitigating layer comprises at least two subgroups,
At least two pairs of the InGaN layer and the GaN layer are alternately stacked.
The InGaN layer has a compressive stress,
The GaN layer has a tensile stress (tensile stress),
The light emitting device of claim 1, wherein the number of InGaN and GaN layers of each subgroup is the same. delete delete delete delete delete delete The method of claim 1,
Wherein the InGaN layer thickness is constant within the subgroup. The method of claim 8,
The thickness of the InGaN layer in the subgroup adjacent to the active layer is thicker than the thickness of the InGaN layer in the subgroup adjacent to the first semiconductor layer. The method of claim 8,
The thickness of the InGaN layer in the subgroup is thicker as the subgroup is closer to the active layer. The method of claim 9,
And the thickness of the GaN layer in each subgroup is the same as the thickness of the GaN layer in the other subgroup. The method according to any one of claims 8 to 10,
Wherein the GaN layer thickness is constant within the subgroup. The method of claim 12,
And a thickness of the GaN layer in the subgroup adjacent to the active layer is thicker than a thickness of the GaN layer in the subgroup adjacent to the first semiconductor layer. The method of claim 12,
The thickness of the GaN layer in the subgroup is thicker as the subgroup is closer to the active layer. delete delete delete delete delete

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