KR20140099071A

KR20140099071A - Light emitting device

Info

Publication number: KR20140099071A
Application number: KR1020130011840A
Authority: KR
Inventors: 임정순
Original assignee: 엘지이노텍 주식회사
Priority date: 2013-02-01
Filing date: 2013-02-01
Publication date: 2014-08-11
Also published as: KR102020493B1

Abstract

According to an embodiment of the present invention, a light emitting device includes a substrate including Si; a buffer layer arranged on the substrate; a strain reducing layer arranged on the buffer layer to reduce a strain generated on the semiconductor layer; and a light emitting structure which is arranged on the strain reducing layer and includes a first semiconductor layer, a second semiconductor layer, and an active layer between the first semiconductor layer and the second semiconductor layer. The buffer layer includes a first buffer layer. The first buffer layer includes AIN and is doped by an n type dopant.

Description

[0001]

An embodiment relates to a light emitting element.

As a typical example of a light emitting device, a light emitting diode (LED) is a device for converting an electric signal into an infrared ray, a visible ray, or a light using the characteristics of a compound semiconductor, and is used for various devices such as household appliances, remote controllers, Automation equipment, and the like, and the use area of LEDs is gradually widening.

In general, miniaturized LEDs are made of a surface mounting device for mounting directly on a PCB (Printed Circuit Board) substrate, and an LED lamp used as a display device is also being developed as a surface mounting device type . Such a surface mount device can replace a conventional simple lighting lamp, which is used for a lighting indicator for various colors, a character indicator, an image indicator, and the like.

As the use area of the LED is widened as described above, it is important to increase the luminance of the LED as the brightness required for a lamp used in daily life and a lamp for a structural signal is increased.

In addition, the electrode of the light emitting device should have excellent adhesive force and excellent electrical characteristics.

Further, research is underway to improve the probability of recombination of electrons and holes in the active layer of the light emitting device.

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

The embodiment provides a light emitting device that mitigates strain generated between the first semiconductor layer and the substrate and improves the quality of the light emitting structure.

A light emitting device according to an embodiment includes a substrate including Si, a buffer layer disposed on the substrate, a strain relaxation layer disposed on the buffer layer to relax a strain generated in the semiconductor layer, And a light emitting structure including a first semiconductor layer, a second semiconductor layer, and an active layer between the first semiconductor layer and the second semiconductor layer, wherein the buffer layer includes a first buffer layer, Comprises AlN and is doped with an n-type dopant.

The embodiment has the advantage that the buffer layer is doped with a high concentration of Si, thereby controlling lattice mismatch in advance between the substrate and the buffer layer.

In addition, since the buffer layer is used in this embodiment, the thickness of the strain relief layer can be reduced, and the structure can be simplified, which has the advantage of shortening the manufacturing time of the light emitting device.

In addition, since the embodiment uses Si as the impurity of the buffer layer and uses the same material as the substrate, it has an advantage that it can be manufactured in one process.

In addition, the buffer layer of the embodiment includes the substrate material, and has an advantage that the quality of the light emitting element is also excellent.

In addition, the embodiment relaxes 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 illustrating a light emitting device according to an embodiment,
FIG. 2 is an enlarged sectional view of a portion A of the light emitting device of FIG. 1,
FIG. 3 is an enlarged cross-sectional view of a portion B of the light emitting device of FIG. 1,
FIG. 4 is an enlarged cross-sectional view of a light emitting device according to another embodiment of FIG. 1,
FIG. 5 is an enlarged cross-sectional view of a light emitting device according to another embodiment of FIG. 1,
6 is a perspective view of a light emitting device package including a light emitting device according to an embodiment,
7 is a cross-sectional view of a light emitting device package including a light emitting device according to an embodiment,
8 is an exploded perspective view of a display device having a light emitting device according to an embodiment.
9 is a view showing a display device having a light emitting device according to an embodiment.
10 is an exploded perspective view of a lighting device having a light emitting device according to an embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element. Thus, the exemplary term "below" can include both downward and upward directions. The elements can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size and area of each component do not entirely reflect actual size or area.

Further, the angle and direction mentioned in the description of the structure of the light emitting device in the embodiment are based on those shown 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 an enlarged sectional view of a portion A of the light emitting device of FIG. 1, FIG. 3 is an enlarged sectional view of a portion B of the light emitting device of FIG. 1, and FIG. 4 is a cross- FIG. 5 is an enlarged cross-sectional view of a light emitting device according to another embodiment of FIG. 1; FIG.

1, a light emitting device 100 according to an embodiment includes a substrate 110, a buffer layer 115 on the substrate 110, a strain relief layer 140 and a strain relief layer 140 on the buffer layer 115, Lt; RTI ID = 0.0 > 160 < / RTI >

The light emitting structure 160 may include a first semiconductor layer 120, an active layer 130, and a second semiconductor layer 150.

The substrate 110 may be formed of a material having optical transparency, for example, silicon (Si). However, it is preferable that the refractive index of the substrate 110 is smaller than the refractive index of the first semiconductor layer 120 for light extraction efficiency.

On the other hand, a PSS (Patterned SubStrate) structure may be provided on the upper surface of the substrate 110 to enhance light extraction efficiency. The substrate 110 referred to herein may or may not have a PSS structure.

A buffer layer 115 is formed on the substrate 110 to mitigate lattice mismatch between the substrate 110 and the first semiconductor layer 120 (or the strain relieving layer 140) and allow the semiconductor layer to grow easily Can be located. The buffer layer 115 will be described later.

On the buffer layer 115, a strain relaxation layer 140 is disposed to relax the strain of the semiconductor layer. The strain relief layer 140 may have a supper lattice structure to mitigate the strain generated in the light emitting structure 160. The description of the strain relief layer 140 will be described later.

An undoped semiconductor layer (not shown) may be located on the strain relief layer 140. The undoped semiconductor layer is a nitride semiconductor layer which is not intentionally implanted with n-type impurity, but can have an 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 active layer 130, and the second semiconductor layer 150 may be formed on the unprocessed semiconductor layer.

The first semiconductor layer 120 may be located on the un-doped semiconductor layer. The first semiconductor layer 120 may be formed of an n-type semiconductor layer and may provide electrons to the active layer 130. The first semiconductor layer 120 may be a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? _Y? 1, 0? _X + y? For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, and AlInN, and n-type dopants such as Si, Ge, and Sn may be doped.

The active layer 130 may be formed on the first semiconductor layer 120.

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 Group 3-V group elements.

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) And 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 and / or below the active layer 130. 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 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 may be a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? _Y? 1, 0? _X + y? For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN and AlInN, and a p-type dopant such as Mg, Zn, Ca, Sr and Ba may be doped.

A current blocking layer (not shown) may be formed between the active layer 130 and the second semiconductor layer 150, and electrons injected from the first semiconductor layer 120 into the active layer 130 May be an electron blocking layer for preventing the second semiconductor layer 150 from being recombined in the active layer 130 and flowing to the second semiconductor layer 150. The current blocking layer has a band gap relatively larger than that of the active layer 130 so that electrons injected from the first semiconductor layer 130 are injected into the second semiconductor layer 150 without being recombined in the active layer 130 . Accordingly, it is possible to increase the probability of recombination of electrons and holes in the active layer 140 and to prevent a leakage current.

On the other hand, the current blocking layer may have a band gap larger than the band gap of the barrier layer included in the active layer 130, and may be formed of a semiconductor layer containing 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 formed using a metal organic chemical vapor deposition (MOCVD) method, a chemical vapor deposition (CVD) method, ), A plasma enhanced chemical vapor deposition (PECVD) method, a molecular beam epitaxy (MBE) method, a hydride vapor phase epitaxy (HVPE) method, or a sputtering method The present invention 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 can be uniformly or nonuniformly formed. That is, the plurality of semiconductor layers may be formed to have various doping concentration distributions, but the invention is not limited thereto.

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

The active layer 130 and the second semiconductor layer 150 may be partially removed to expose a portion of the first semiconductor layer 120. The exposed first semiconductor layer 120 may include a first electrode 172, Can be formed. That is, the first semiconductor layer 120 includes a top surface facing the active layer 130 and a bottom surface facing the substrate 110, and an upper surface includes a region exposed at least one region, As shown in FIG.

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

A 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 to 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 , RuOx, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO.

The second electrode 174 may be formed on the transparent electrode layer 180.

The first and second electrodes 172 and 174 may be formed of a conductive material such as In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, And may include metals selected from Ti, Ag, Cr, Mo, Nb, Al, Ni, Cu, and Ti, or an alloy thereof and may be formed as a single layer or a multilayer .

Referring to FIG. 2, the strain relieving layer 140 may be formed by alternately stacking at least two pairs of InGaN layers and GaN layers. Preferably, the strain relief layer 140 may comprise at least two subgroups. In FIG. 2, three subgroups 141, 143, and 145 are shown, but the present invention is not limited thereto. The first subgroup 141 is adjacent to the buffer layer 115 among the subgroups 141, 143 and 145 and the second subgroup 143 and the third subgroup 145 in the direction of the first semiconductor layer 120. [ .

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

On the other hand, the subgroups 141, 143, and 145 may be formed by alternately stacking at least two pairs of InGaN layers and GaN layers. More preferably three pairs to eight pairs can be alternately stacked.

The thickness of each of the subgroups 141, 143, and 145 may be thicker toward the first semiconductor layer 120. When the thickness of each of the subgroups 141, 143 and 145 becomes thicker as the first semiconductor layer 120 is adjacent to the first semiconductor layer 120, the first semiconductor layer 120 has a structure similar to that of the first semiconductor layer 120, The lattice constant of the strain relieving layer 140 becomes closer to that of the first semiconductor layer 120 and the strain can be reduced as the stress relaxation layer 115 progresses from the first semiconductor layer 120 to the first semiconductor layer 120.

The arrangement in which the thickness of each subgroup 141, 143, 145 becomes thicker as it is adjacent to the first semiconductor layer 120 may have various arrangements.

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

The number of the InGaN layers 141A, 143A, and 145A and the number of the GaN layers 141B, 143B, and 145B in the subgroups 141, 143, and 145 are the same. For example, the number of InGaN layers 141A in the first subgroup 141 and the number of InGaN layers 143A and 145A in the second subgroup 143 and the third subgroup 145 are set to be the same And the number of the GaN layers 141B in the first subgroup 141 and the number of the GaN layers 143B and 145B in the second subgroup 143 and the third subgroup 145 are the same.

It is preferable that the thicknesses of the InGaN layers 141A, 143A, 145A and the GaN layers 141B, 143B, 145B are uniformly arranged in the subgroups 141, 143, 145. That is, the thicknesses of the InGaN layers 141A, 143A, and 145A and the GaN layers 141B, 143B, and 145B may be different 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 1 nm to 1 mu m and the thicknesses of the GaN layers 141B, 143B and 145B may be InGaN layers 141A, ) &Lt; / RTI >

Another example of the arrangement in which the thickness of each subgroup 141, 143, 145 becomes thicker toward the first semiconductor layer 120 is as follows. However, the above description is premised.

For example, the thickness of the InGaN layer in the subgroup adjacent to the first semiconductor layer 120 may be greater than the thickness of the InGaN layer in the subgroup adjacent to the buffer layer 115. That is, the thickness of the InGaN layer 143A in the second subgroup 143 may be greater than the thickness of the InGaN layer 141A in the first subgroup 141, and the thickness of the InGaN layer 145A May be thicker than the thickness of the InGaN layer 143A in the second subgroup 143. [ In other words, the thicknesses of the InGaN layers 141A, 143A, and 145A may be thicker as the subgroups 141, 143, and 145 are adjacent to the first semiconductor layer 120. At this time, the GaN layers 141B, 143B and 145B of the subgroups 141, 143 and 145 are constant in thickness or the GaN layers 141B, 143B and 145B of the subgroups 141, 143 and 145 adjacent to the first semiconductor layer 120 It can be formed thick.

As another example, the thickness of the GaN layer in the subgroup adjacent to the first semiconductor layer 120 may be greater than the thickness of the GaN layer in the subgroup adjacent to the first semiconductor layer 120. That is, the thickness of the GaN layer 143B in the second subgroup 143 may be greater than the thickness of the GaN layer 141B in the first subgroup 141, and the thickness of the GaN layer 145B May be thicker than the thickness of the GaN layer 143B in the second subgroup 143. [ The thickness of the GaN layers 141B, 143B, and 145B may be thicker as the subgroups 141, 143, and 145 are adjacent to the first semiconductor layer 120. [ At this time, the InGaN layers 141A, 143A and 145A of the subgroups 141, 143 and 145 are constant in thickness or the InGaN layers 141A, 143A and 145A of the subgroups 141, 143 and 145 adjacent to the first semiconductor layer 120 It can be formed thick.

When the thicknesses of the InGaN layer and the GaN layer of the subgroups 141, 143 and 145 are increased as they are adjacent to the first semiconductor layer 120, the strain generated between the buffer layer 115 or the substrate 110 and the first semiconductor layer 120 Relax.

The embodiment is not to change the strain abruptly in the strain relieving layer 140 but rather to alternately laminate the layers having tensile and compressive strains alternately first thinly and then thickly alternately and gradually changing the strain The strain between the substrate 110 or the buffer layer 115 and the first semiconductor layer 120 can be relaxed.

The In content of the InGaN layers 141A, 143A and 145A can be made higher as the InGaN layers 141A, 143A and 145A of the subgroups 141, 143 and 145 adjacent to the first semiconductor layer 120 are. Here, the In content means the mole ratio or mass ratio of In in InGaN.

Hereinafter, the buffer layer 115 will be described in detail with reference to FIGS. 3 to 5. FIG.

The buffer layer 115 may be formed in a low temperature atmosphere and may be made of a material capable of alleviating the difference in lattice constant between the semiconductor layer and the substrate 110.

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

The thickness of the buffer layer 115 is preferably 10 nm to 300 nm. When the thickness of the buffer layer 115 is thinner than 10 nm, there is no effect of mitigating lattice mismatch. When the thickness of the buffer layer 115 is thicker than 300 nm, the manufacturing cost is increased and the effect of mitigating lattice mismatch is insignificant.

The buffer layer 115 may have various structures, but may include a first buffer layer 115a, a second buffer layer 115b, and / or a third buffer layer 115c. For example, the buffer layer 115 may include a first buffer layer 115a and may include a first buffer layer 115a and a second buffer layer 115b on the first buffer layer 115a, A third buffer layer 115c may be formed on the buffer layer 115a and the first buffer layer 115a and a second buffer layer 115b may be formed on the first buffer layer 115a and the first buffer layer 115a, And a third buffer layer 115c may be formed on the buffer layer 115b. Figs. 3 to 5 show embodiments of the buffer layer 115. Fig.

The first buffer layer 115a may be selected from an AlN material, for example. The first buffer layer 115a can be doped with an n-type dopant, and more preferably, can be doped with an Si dopant. When doped with Si in the first buffer layer 115a, its doping concentration is preferably greater than 10e ^{19 /} cm ³ .

When the buffer layer 115 includes the first buffer layer 115a, the first buffer layer 115a is doped with a high concentration of Si so that the advantage of controlling the lattice mismatch in advance between the substrate 110 and the buffer layer 115 . Further, when Si is used as an impurity, it has the advantage that it can be manufactured in the same process with the same material as the substrate.

In addition, since the buffer layer 115 is used, the thickness of the strain relief layer 140 can be reduced, and the structure can be simplified, thereby shortening the manufacturing time of the light emitting device.

The lattice constant between the substrate 110 and the buffer layer 115 can be reduced by using the same material as the material of the substrate 110 as a dopant and the same material is included in the substrate 110 and the buffer layer 115 And the quality is also excellent.

The second buffer layer 115b includes AlN, is doped with an n-type dopant, and the doping concentration of the n-type dopant decreases as it goes toward the strain relaxation layer. More preferably, the above-mentioned n-type dopant may include Si. For example, one region of the second buffer layer 115b adjacent to the first buffer layer 115a may have a doping concentration similar to that of the first buffer layer 115a and may have a doping concentration similar to that of the second buffer layer 115b adjacent to the first semiconductor layer 120 The other region may not be doped with an n-type dopant. The doping concentration of the n-type dopant in the second buffer layer 115b may vary linearly or non-linearly. However, the present invention is not limited thereto.

When the buffer layer 115 is formed of the first buffer layer 115a and the second buffer layer 115b on the first buffer layer 115a, the doping concentration of the second buffer layer 115b linearly changes, The lattice mismatch occurring on the buffer layer 115 and the strain relaxation layer 140 or on the first semiconductor layer 120 can be further mitigated.

The third buffer layer 115c may include undoped AlN. The third buffer layer 115c serves to prevent impurities of the buffer layer 115 from diffusing into the strain relief layer 140. [ That is, the third buffer layer 115c functions to cap the buffer layer 115. [ Therefore, there is an advantage of preventing deterioration of the strain relief layer 140 and / or the first semiconductor layer 120 formed on the buffer layer 115.

FIG. 6 is a perspective view illustrating a light emitting device package including the light emitting device according to the embodiment, and FIG. 7 is a cross-sectional view illustrating a light emitting device package including the light emitting device according to the embodiment.

6 and 7, the light emitting device package 500 includes a body 510 having a cavity 520 formed therein, first and second lead frames 540 and 550 mounted on the body 510, A light emitting device 530 electrically connected to the first and second lead frames 540 and 550 and an encapsulant (not shown) encapsulated in the cavity 520 to cover the light emitting device 530.

The body 510 may be made of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), liquid crystal polymer (PSG), polyamide 9T (SPS), a metal material, sapphire (Al ₂ O ₃ ), beryllium oxide (BeO), and a printed circuit board (PCB). The body 510 may be formed by injection molding, etching, or the like, but is not limited thereto.

The inner surface of the body 510 may be formed with an inclined surface. The reflection angle of the light emitted from the light emitting device 530 can be changed according to the angle of the inclined surface, and thus the directivity angle of the light emitted to the outside can be controlled.

Concentration of light emitted to the outside from the light emitting device 530 increases as the directivity angle of light decreases. Conversely, as the directivity angle of light increases, the concentration of light emitted from the light emitting device 530 decreases.

The shape of the cavity 520 formed in the body 510 may be circular, rectangular, polygonal, elliptical, or the like, and may have a curved shape, but the present invention is not limited thereto.

The light emitting element 530 is mounted on the first lead frame 540 and may be a light emitting element that emits light such as red, green, blue, or white, or a UV (Ultra Violet) However, the present invention is not limited thereto. In addition, one or more light emitting elements 530 may be mounted.

The light emitting device 530 may be a horizontal type or a vertical type formed on the upper or lower surface of the light emitting device 530 or a flip chip Applicable.

The 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, or other resin material. The encapsulant may be filled in the cavity 520 and ultraviolet or thermally cured.

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

The phosphor may be one of a blue light emitting phosphor, a blue light emitting phosphor, a green light emitting phosphor, a sulfur 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 depending on the wavelength of light emitted from the light emitting device 530 Can be applied.

That is, the phosphor may be excited by the 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 blue light and blue light emitted from the blue light emitting diode As the excited yellow light is mixed, the light emitting device package 500 can provide white light.

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

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

The first and second lead frames 540 and 550 may be formed of a metal material such as titanium, copper, nickel, gold, chromium, tantalum, (Pt), tin (Sn), silver (Ag), phosphorus (P), aluminum (Al), indium (In), palladium (Pd), cobalt (Co), silicon (Si), germanium , Hafnium (Hf), ruthenium (Ru), and iron (Fe). Also, the first and second lead frames 540 and 550 may be formed to have a single layer or a multilayer structure, but the present invention is not limited thereto.

The first and second lead frames 540 and 550 are separated from each other and electrically separated from each other. The light emitting element 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 element 530, And may be electrically connected through a conductive material such as a conductive material. 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. Accordingly, when power is supplied to the first and second lead frames 540 and 550, power may be applied to the light emitting device 530. Meanwhile, a plurality of 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 can be applied to a lighting device. The lighting system includes a structure in which a plurality of light emitting elements are arrayed and includes a display device shown in Figs. 8 and 9, a lighting device shown in Fig. 10, and may include a lighting lamp, a traffic light, a vehicle headlight, have.

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

8, a display apparatus 1000 according to an embodiment includes a light guide plate 1041, a light source module 1031 for providing light to the light guide plate 1041, and a reflection member 1022 An optical sheet 1051 on the light guide plate 1041 and a display panel 1061 on the optical sheet 1051 and the light guide plate 1041 and the light source module 1031 and the reflection member 1022 But is not limited to, a bottom cover 1011.

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

The light guide plate 1041 serves to diffuse light into a surface light source. The light guide plate 1041 may be made of a transparent material, for example, acrylic resin such as polymethylmethacrylate (PET), polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin copolymer (COC), and polyethylene naphtha late Resin. &Lt; / RTI >

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

The light source module 1031 includes at least one light source module 1031 and may directly or indirectly provide light from one side of the light guide plate 1041. The light source module 1031 includes a substrate 1033 and a light emitting device 1035 according to the embodiment described above and the light emitting devices 1035 may be arrayed at a predetermined interval on the substrate 1033 .

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), a flexible PCB (FPCB), and the like. When the light emitting element 1035 is mounted on the side surface of the bottom cover 1011 or on the heat radiation plate, the substrate 1033 can be removed. Here, a part of the heat radiating plate may be in contact with the upper surface of the bottom cover 1011.

The plurality of light emitting devices 1035 may be mounted on the substrate 1033 such that the light emitting surface is spaced apart from the light guiding plate 1041 by a predetermined distance. However, the present invention is not limited thereto. The light emitting device 1035 may directly or indirectly provide light to the light-incident portion, which is one surface of the light guide plate 1041, but the present invention is not limited thereto.

The reflective member 1022 may be disposed under the light guide plate 1041. The reflection member 1022 reflects the light incident on the lower surface of the light guide plate 1041 so as to face upward, thereby improving the brightness of the light unit 1050. 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 house 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 a housing portion 1012 having a box-like shape with an opened upper surface, but the present invention is not limited thereto. The bottom cover 1011 may be coupled to 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 a non-metal material having good thermal conductivity, but the present invention is not limited thereto.

The display panel 1061 is, for example, an LCD panel, including first and second transparent substrates facing each other, and a liquid crystal layer interposed between the first and second substrates. A polarizing plate may be attached to at least one surface of the display panel 1061, but the present invention is not limited thereto. The display panel 1061 displays information by light passing through the optical sheet 1051. Such a display device 1000 can be applied to various types of 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-transmitting sheet. The optical sheet 1051 may include at least one of a sheet such as a diffusion sheet, a horizontal and vertical prism sheet, and a brightness enhancement sheet. The diffusion sheet diffuses incident light, and the horizontal and / or vertical prism sheet condenses incident light into a display area. The brightness enhancing sheet improves the brightness by reusing the lost light. A protective sheet may be disposed on the display panel 1061, but the present invention is not limited thereto.

Here, the optical path of the light source module 1031 may include the light guide plate 1041 and the optical sheet 1051 as an optical member, but the invention is not limited thereto.

9 is a view showing a display device having a light emitting device according to an embodiment.

9, the display device 1100 includes a bottom cover 1152, a substrate 1120 on which the above-described light emitting device 1124 is arrayed, 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 a receiving portion 1153, but the present invention 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, a horizontal and vertical prism sheet, 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 incident light, and the horizontal and vertical prism sheets condense incident light into a display area. The brightness enhancing sheet enhances brightness by reusing the lost light.

The optical member 1154 is disposed on the light source module 1160 and performs surface light source, diffusion, and light condensation of light emitted from the light source module 1160.

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

10, the lighting apparatus according to the embodiment includes a cover 2100, a light source module 2200, a heat discharger 2400, a power supply unit 2600, an inner case 2700, and a socket 2800 . Further, the illumination device according to the embodiment may further include at least one of the member 2300 and the holder 2500. The light source module 2200 may include a light emitting device according to an embodiment of the present invention.

For example, the cover 2100 may have a shape of a bulb or a hemisphere, and may be provided in a shape in which the hollow is hollow and a part is opened. The cover 2100 may be optically coupled to the light source module 2200. For example, the cover 2100 may diffuse, scatter, or excite 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 discharging body 2400. The cover 2100 may have an engaging portion that engages with the heat discharging body 2400.

The inner surface of the cover 2100 may be coated with a milky white paint. Milky white paints may contain a diffusing agent to diffuse light. The surface roughness of the inner surface of the cover 2100 may be larger than the surface roughness of the outer surface of the cover 2100. This is for sufficiently diffusing and diffusing the light from the light source module 2200 and emitting it 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 so that the light source module 2200 is visible from the outside, and may be opaque. The cover 2100 may be formed by blow molding.

The light source module 2200 may be disposed on one side of the heat discharging body 2400. Accordingly, heat from the light source module 2200 is conducted to the heat discharger 2400. The light source module 2200 may include a light emitting device 2210, a connection plate 2230, and a connector 2250.

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

The surface of the member 2300 may be coated or coated with a light reflecting material. For example, the surface of the member 2300 may be coated or coated with a white paint. The member 2300 reflects the light reflected by the inner surface of the cover 2100 toward the cover 2100 in the direction toward the light source module 2200. Therefore, the light efficiency of the illumination device according to the embodiment can be improved.

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 can be made between the heat discharging body 2400 and the connecting plate 2230. The member 2300 may be formed of an insulating material to prevent an electrical short circuit between the connection plate 2230 and the heat discharging body 2400. The heat discharger 2400 receives heat from the light source module 2200 and heat from the power supply unit 2600 to dissipate heat.

The holder 2500 blocks the receiving groove 2719 of the insulating portion 2710 of the inner case 2700. Therefore, the power supply unit 2600 housed in the insulating portion 2710 of the inner case 2700 is sealed. The holder 2500 has a guide protrusion 2510. The guide protrusion 2510 may have 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 and provides the electrical signal to the light source module 2200. The power supply unit 2600 is housed in the receiving groove 2719 of the inner case 2700 and is sealed inside 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 portion 2630 has a shape protruding outward from one side of the base 2650. The guide portion 2630 may be inserted into the holder 2500. A plurality of components may be disposed on one side of the base 2650. The plurality of components include, for example, a DC converter for converting AC power supplied from an external power source into DC power, a driving chip for controlling driving of the light source module 2200, an ESD (ElectroStatic discharge) protective device, and the like, but the present invention is not limited thereto.

The protrusion 2670 has a shape protruding outward from the other side of the base 2650. The protrusion 2670 is inserted into the connection portion 2750 of the inner case 2700 and receives an external electrical signal. For example, the protrusion 2670 may be equal to or smaller than the width of the connection portion 2750 of the inner case 2700. One end of each of the positive wire and the negative wire is electrically connected to the protrusion 2670 and the other end of the positive wire and the negative wire are electrically connected to the socket 2800.

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

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

A substrate comprising Si;
A buffer layer disposed on the substrate;
A strain relief layer disposed on the buffer layer to relax strain generated in the semiconductor layer; And
And a light emitting structure disposed on the strain relief layer and including a first semiconductor layer, a second semiconductor layer, and an active layer between the first semiconductor layer and the second semiconductor layer,
Wherein the buffer layer comprises a first buffer layer,
Wherein the first buffer layer comprises AlN and is doped with an n-type dopant.

The method according to claim 1,
And the n-type dopant of the first buffer layer comprises Si.

The method according to claim 1,
Wherein the doping concentration of the n-type dopant in the first buffer layer is greater than 10e ^{19 /} cm ³ .

The method according to claim 1,
And the thickness of the buffer layer is 10 nm to 300 nm.

The method according to claim 1,
The buffer layer may be formed,
Further comprising a second buffer layer on the first buffer layer,
The second buffer layer
And the doping concentration of the n-type dopant decreases as the doping concentration of the n-type dopant increases toward the strain relaxation layer.

6. The method according to claim 1 or 5,
The buffer layer may be formed,
Further comprising a third buffer layer on the first buffer layer,
And the third buffer layer comprises undoped AlN.

The method according to claim 1,
The strain-
Two pairs of InGaN layers and GaN layers are alternately stacked.

The method according to claim 1,
The strain-
Comprising at least two subgroups,
Wherein at least two pairs of the InGaN layer and the GaN layer are stacked in the subgroup, and the thickness of the subgroup is thicker toward the first semiconductor layer.

The method according to claim 1,
Wherein the number of the InGaN layers and the number of GaN layers in each subgroup are equal to each other.

9. The method of claim 8,
The InGaN layer has a compressive stress,
Wherein the GaN layer has a tensile stress.

10. The method of claim 9,
Wherein the thickness of the InGaN layer is constant in the subgroup.

12. The method of claim 11,
Wherein the GaN layer thickness is constant in the subgroup.

The method according to claim 1,
And the In content of the InGaN layer in the subgroup is higher as the subgroup is closer to the first semiconductor layer.

The method according to claim 1,
And the thickness of the InGaN layer and the GaN layer is 1 nm to 1 占 퐉.

The method according to claim 1,
The strain relief layer has a lattice structure.

The method according to claim 1,
And a light transmitting electrode layer for spreading a current on the second semiconductor layer.

The method according to claim 1,
A first electrode electrically connected to the first semiconductor layer, and a second electrode electrically connected to the second semiconductor layer.

A light emitting device package comprising the light emitting device according to any one of claims 1 to 17.

An illumination system comprising the light-emitting device of any one of claims 1 to 17.

A display device comprising the light-emitting element according to any one of claims 1 to 17.