KR20150113525A - Light emitting device having optical structure - Google Patents

Light emitting device having optical structure Download PDF

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Publication number
KR20150113525A
KR20150113525A KR1020140037581A KR20140037581A KR20150113525A KR 20150113525 A KR20150113525 A KR 20150113525A KR 1020140037581 A KR1020140037581 A KR 1020140037581A KR 20140037581 A KR20140037581 A KR 20140037581A KR 20150113525 A KR20150113525 A KR 20150113525A
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layer
light emitting
substrate
optical structure
emitting element
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KR1020140037581A
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Korean (ko)
Inventor
서덕일
김경완
윤여진
우상원
김지혜
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서울바이오시스 주식회사
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Publication of KR20150113525A publication Critical patent/KR20150113525A/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/10—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a light reflecting structure, e.g. semiconductor Bragg reflector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/12—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a stress relaxation structure, e.g. buffer layer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26—Materials of the light emitting region
    • H01L33/30—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table
    • H01L33/32—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table containing nitrogen

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Led Devices (AREA)

Abstract

A light emitting device according to one embodiment of the present invention includes a first conductive nitride semiconductor layer, an active layer, and a second conductive nitride semiconductor layer which are successively laminated on a substrate. Also, the light emitting device includes an optical structure which is interposed between the substrate and the active layer and includes an AlN pattern layer.

Description

[0001] The present invention relates to a light emitting device having an optical structure,

This disclosure relates to light emitting devices, and more particularly to light emitting devices having optical structures that increase the light extraction efficiency.

Generally, the light emitting element is an element including an n-type semiconductor layer, a p-type semiconductor layer, and an active layer located between the n-type and p-type semiconductor layers. Electrons and holes are injected into the active layer when a forward current is applied to the n-type and p-type semiconductor layers, and electrons injected into the active layer are recombined to emit light.

The efficiency of such a light emitting device is determined by internal quantum efficiency and light extraction efficiency. In order to increase the light extraction efficiency, a method of forming a concave-convex pattern on a substrate, such as a patterned sapphire substrate (PSS), and then growing a semiconductor layer on the concave-convex pattern has been proposed. The PSS scatters light incident on the substrate, thereby preventing light from being absorbed or lost through the substrate.

Recently, a technique has been proposed in which a dispersion type Bragg reflector layer for alternately stacking two kinds of materials having different refractive indexes is applied to the inside of the light emitting device. The scattered Bragg reflection layer may be configured to reflect light of a specific wavelength depending on physical properties of the two kinds of materials constituting the scattered Bragg reflection layer. In the case where the active layer emits light of the specific wavelength, the reflection efficiency of the light can be increased by increasing the reflection of the light using the scattered Bragg reflection layer. As an example of a recent technology for applying a distributed Bragg reflector layer to light of a specific wavelength, there is a technique disclosed in Korean Patent Laid-Open Publication No. 2014-0008093.

Embodiments of the present invention provide a light emitting device having an optical structure for performing epitaxial growth of a nitride semiconductor layer while performing a function of increasing light emission efficiency from the inside of the light emitting device.

A light emitting device according to an aspect of the present invention is disclosed. The light emitting device includes a substrate, and a first conductive type nitride semiconductor layer, an active layer, and a second conductive type nitride semiconductor layer sequentially stacked on the substrate. In addition, the light emitting device includes an optical structure interposed between the substrate and the active layer and including an aluminum nitride pattern layer.

A light emitting device according to another aspect of the present invention is disclosed. The light emitting devices include an optical structure including an oxide compound pattern layer and an aluminum nitride pattern layer disposed discontinuously on a different substrate and alternately stacked on each other. The light emitting device includes a first conductive type nitride semiconductor layer, an active layer, and a second conductive type nitride semiconductor layer sequentially stacked on the different substrate on which the optical structure is located.

According to an embodiment of the present invention, the light emitting device may include an optical structure including an aluminum nitride pattern layer. When the aluminum nitride pattern layer is disposed on one surface of the heterogeneous substrate, the nitride semiconductor layer can function as a buffer layer for epitaxially growing the nitride semiconductor layer on the substrate.

Since the optical structure has the scattered Bragg reflection layer, it is possible to effectively reflect the light moving toward the lower substrate. The optical structure can have a high reflectance for light in a wavelength range of about 400 to about 800 nm, which is a visible light region, and can accelerate reflection toward the light emitting surface with respect to incident light. As a result, the light extraction efficiency of the light emitting device can be improved.

In addition, the optical structure is arranged in the light emitting device discontinuously in the form of a pattern structure, so that the optical structure can function as a scattering center of light, so that refraction or transmission of light toward the substrate can be suppressed.

1 is a cross-sectional view schematically showing a light emitting device according to a first embodiment of the present invention.
2 is a cross-sectional view schematically showing a light emitting device according to a second embodiment of the present invention.
3 is a cross-sectional view schematically showing a light emitting device according to a third embodiment of the present invention.
4 is a cross-sectional view schematically showing a light emitting device according to a fourth embodiment of the present invention.
5 is a cross-sectional view schematically showing a light emitting device according to a fifth embodiment of the present invention.
6 is a cross-sectional view schematically showing a light emitting device according to a sixth embodiment of the present invention.
7 is a graph showing the reflectance of an optical structure according to an embodiment of the present invention.

Embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. However, the techniques disclosed in this disclosure are not limited to the embodiments described herein but may be embodied in other forms. In the drawings, the width, thickness, and the like of the components are enlarged in order to clearly illustrate the components of each device.

Where an element is referred to herein as being located on another element "above" or "below", it is to be understood that the element is directly on the other element "above" or "below" It means that it can be intervened. In this specification, the terms 'upper' and 'lower' are relative concepts set at the observer's viewpoint. When the viewer's viewpoint is changed, 'upper' may mean 'lower', and 'lower' It may mean.

Like numbers refer to like elements throughout the several views. It is to be understood that the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise, and the terms "comprise" Or combinations thereof, and does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

1 is a cross-sectional view schematically showing a light emitting device according to a first embodiment of the present invention. 1, a light emitting device 100 includes a substrate 110, a first conductive type nitride semiconductor layer 130, an active layer 140, and a second conductive type nitride semiconductor layer 130 sequentially disposed on the substrate 110, And a semiconductor layer 150. The light emitting device 100 includes an optical structure 120 interposed between the substrate 110 and the active layer 140.

The substrate 110 may be, for example, a sapphire substrate, a silicon carbide (SiC) substrate, a gallium nitride (GaN) substrate, an aluminum nitride (AlN) substrate, a silicon substrate, Other various types of substrates may be used as long as the conditions for growing the nitride based semiconductor layer such as the semiconductor layer 130 are satisfied. As an example, the substrate 110 may be made of a heterogeneous material in contrast to the nitride based semiconductor layer stacked on top. In particular, the substrate 110 may have a different lattice constant from the nitride based semiconductor layer. As an example, the substrate 110 may be a substrate having surface unevenness or curvature, such as a patterned sapphire substrate (PSS).

The optical structure 120 may be disposed on the substrate 110. As shown, the optical structure 120 may include a patterned structure that is discontinuously arranged on the top surface of the substrate 110. In one embodiment, the optical structure 120 may comprise an aluminum nitride layer. As an example, the optical structure 120 may be a layer of aluminum nitride pattern that is discontinuously arranged.

In another embodiment, the optical structure 120 may comprise an oxide compound layer and an aluminum nitride layer that are alternatively stacked together. As an example, the oxide compound layer may be a silicon oxide layer, an aluminum oxide layer, or the like. 1, the optical structure 120 may include a unit laminated structure 1200 composed of an oxidized compound pattern layer 1210 and an aluminum nitride pattern layer 1220 which are alternately stacked with each other. have. The optical structure 120 may comprise a plurality of pairs of unit laminate structures 1200. At this time, the uppermost pattern layer of the optical structure 120 may be the aluminum nitride pattern layer 1220. As an example, the optical structure 120 may be formed by stacking 10 to 100 pairs of unit laminate structures 120 having a thickness of 80 to 90 nm.

The optical structure 120 may include a distributed Bragg reflection (DBR) that reflects light incident on the optical structure 120. The scattered Bragg reflection layer may correspond to the at least one pair of unit lamination structures 1200. As a specific example, in the optical structure 120, when a unit laminate structure 1200 having a thickness of about 80 to 90 nm is laminated from about 10 to 100 layers, the optical structure 120 has a thickness of 400 nm to 800 nm A Bragg reflection layer having a reflectance of at least 90% or more with respect to the light in the wavelength range of the Bragg reflection layer. Conventionally, the technique has been related to a scattered Bragg reflection layer having a high reflectance for a specific wavelength. On the other hand, in the case of this embodiment, a technique capable of providing a scattered Bragg reflection layer having a high reflectance over the entire region of visible light to be. 1, the optical structure 120 reflects light 135 emitted in a downward direction from the active layer 140 and reflects the light emission efficiency of the light emitting device 100 through the upward light emitting surface .

The optical structure 120 may function as a scattering center for visible light incident on the optical structure 120. As shown, the optical structure 120 has the form of a pattern structure that is discontinuously arranged on the top surface of the substrate 110, thereby effectively scattering the light incident on the optical structure 120. Thus, refraction or transmission of light toward the optical substrate 110 can be suppressed.

In addition, the optical structure 120 may function to mitigate the stress caused by the lattice constant difference between the substrate 110 and the first conductive type nitride semiconductor layer 130. The optical structure 120 may be composed of the aluminum nitride pattern layer 1220 or the aluminum nitride pattern layer 1220 may be arranged in the uppermost layer. Therefore, the first conductive type nitride semiconductor layer 130 may be formed in contact with the aluminum nitride pattern layer 1220. Since the difference in lattice mismatch between the aluminum nitride and the gallium nitride layer (GaN) that can be applied to the first conductive type nitride semiconductor layer 130 is small to about 3%, the aluminum nitride pattern layer 1220 is formed on the gallium nitride layer The first conductive type nitride semiconductor layer 130 such as GaN may be epitaxially grown on the aluminum nitride pattern layer 1220. [

The first conductive type nitride semiconductor layer 130 may be disposed on the optical structure 120. The first conductive type nitride semiconductor layer 130 may be a semiconductor layer doped with an n-type or p-type dopant. In particular, when the first conductive type nitride semiconductor layer 130 is doped with an n-type dopant, the second conductive type nitride semiconductor layer 150 may be doped with a p-type dopant. In contrast, when the first conductive type nitride semiconductor layer 130 is doped with a p-type dopant, the second conductive type nitride semiconductor layer 150 may be doped with an n-type dopant. The n-type dopant may be, for example, silicon (Si). The p-type dopant may be magnesium (Mg), zinc (Zn), cadmium (Cd) or a combination of two or more thereof.

For example, the first conductive type nitride semiconductor layer 130 may include a gallium nitride layer (GaN), an aluminum gallium nitride layer (Al x Ga 1 - x N, 0 < (Al x In y Ga 1 -x- y N, 0? x, y, x + y? 1), or a combination of two or more thereof. .

As illustrated, the first electrode layer 160 may be disposed on a portion of the first conductive type nitride semiconductor layer 130 in the case of a light emitting device having a horizontal structure. The first electrode layer 160 is electrically connected to the light emitting device package through a bonding wire (not shown), thereby receiving a voltage from an external power source and applying a voltage to the first conductive nitride semiconductor layer 130 . The first electrode layer 160 may be formed of a conductive layer, for example, titanium, aluminum, or the like.

The active layer 140 may be disposed on the first conductive type nitride semiconductor layer 130. The active layer 140 generates light through coupling of electrons and holes provided from the first conductive type nitride semiconductor layer 130 and the second conductive type nitride semiconductor layer 150. According to one embodiment, the active layer 140 may have a multi-quantum well structure to enhance coupling efficiency of electron-holes. In one example, the active layer 140 is indium gallium nitride (InGaN), gallium nitride (GaN), gallium aluminum nitride (Ga 1 - a Al a N , 0 <a <1) aluminum indium gallium nitride (Al x In y Ga 1 -x- y N, 0≤x, y , x + y≤1) or may comprise a combination of two or more of these.

The second conductive type nitride semiconductor layer 150 may be disposed on the active layer 140. The second conductive type nitride semiconductor layer 150 may be a semiconductor layer doped with an n-type or p-type dopant. In particular, when the first conductive type nitride semiconductor layer 130 is doped with an n-type dopant, the second conductive type nitride semiconductor layer 150 may be doped with a p-type dopant. In contrast, when the first conductive type nitride semiconductor layer 130 is doped with a p-type dopant, the second conductive type nitride semiconductor layer 150 may be doped with an n-type dopant. The n-type dopant may be, for example, silicon (Si). The p-type dopant may be magnesium (Mg), zinc (Zn), cadmium (Cd) or a combination of two or more thereof.

As an example, the second conductive type nitride semiconductor layer 150 may include a gallium nitride layer (GaN), an aluminum gallium nitride layer (Al x Ga 1 - x N, 0 < (Al x In y Ga 1 -x- y N, 0? x, y, x + y? 1), or a combination of two or more thereof. .

A second electrode layer 170 may be disposed on a portion of the second conductive type nitride semiconductor layer 150. The second electrode layer 170 is electrically connected to the light emitting device package through a bonding wire (not shown) to receive a voltage from an external power source and provide the second conductive layer to the second conductive type nitride semiconductor layer 150 . The second electrode layer 170 may be formed as a conductive layer, and may include, for example, titanium, aluminum, and the like.

As described above, in this embodiment, the light emitting device 100 includes the optical structure 120 disposed between the substrate 110 and the first conductive type nitride semiconductor layer 130. The optical structure 120 may comprise an aluminum nitride pattern layer. Specifically, it may be a structure composed of an aluminum nitride pattern layer, or a structure in which a unit laminate structure in which an oxide compound pattern layer and an aluminum nitride pattern layer are alternately stacked is stacked in a plurality of pairs. The optical structure 120 can have a reflectivity of at least 90% or more with respect to incident incident light and can promote epitaxial growth of the nitride semiconductor layer on the aluminum nitride pattern layer.

In general, the light emitting device 100 may be designed to emit light of a specific wavelength in the active layer 140. [ However, according to the inventor, the light having a predetermined single wavelength generated in the active layer 140 may exist in the light emitting device 100 in a state of being converted into light of various wavelength ranges for various reasons. As an example, the blue light emitted from the light emitting device 100 as a chip may be wavelength-converted by an external yellow phosphor and re-incident into the light emitting device 100 in the state of yellow light. Based on the above-described phenomenon, the inventor determines that a reflective layer capable of reflecting not only the wavelength of light emitted from the active layer 140 but also light of various other visible light wavelength ranges may be requested to the light emitting element 100. The embodiment of the present invention can provide a scattered Bragg reflection layer having a sufficiently high reflectivity for the entire region of the visible light wavelength.

2 is a cross-sectional view schematically showing a light emitting device according to a second embodiment of the present invention. 2, the light emitting device 200 includes the light emitting device 100 of the first embodiment described above with reference to FIG. 1 except for the structure of the first conductive type nitride semiconductor layer 230 and the active layer 230, And its configuration are substantially the same. Therefore, in the following description, configurations differentiated from each other will be described.

Referring to FIG. 2, after the optical structure 120 is formed as a discrete pattern structure on the substrate 110, a first conductive type nitride semiconductor layer 230 may be formed on the substrate 110. At this time, the first conductive type nitride semiconductor layer 230 may be stacked along the pattern of the optical structure 120. As illustrated, the first conductive nitride semiconductor layer 230 may be formed along the shape of the optical structure 120 such that the upper surface of the first conductive nitride semiconductor layer 230 has vertical bending. Such lamination may be achieved by forming the first conductive nitride semiconductor layer 230, for example, by controlling the process temperature, the process pressure, the deposition rate, and the like.

The active layer 240 may also be formed along the curvature formed on the upper surface of the first conductive type nitride semiconductor layer 230. Since the active layer 240 has a vertical bending, the area of the active layer 240 can be increased, thereby increasing the amount of light emitted through the active layer 240.

A second conductive type nitride semiconductor layer 150 may be formed on the active layer 240. The second conductive type nitride semiconductor layer 150 may be formed to cover the active layer 240 along the curvature of the active layer 240. The configuration of the second conductive type nitride semiconductor layer 150 may be substantially the same as the configuration of the second conductive type nitride semiconductor layer 150 in the first embodiment described above with reference to FIG.

3 is a cross-sectional view schematically showing a light emitting device according to a third embodiment of the present invention. Referring to FIG. 3, the light emitting device 300 is substantially the same as the light emitting device 100 of the first embodiment described above with reference to FIG. 1, except that a buffer layer 325 is added. Therefore, in the following description, configurations differentiated from each other will be described.

The buffer layer 325 of FIG. 3 may be disposed between the substrate 110 and the first conductive type nitride semiconductor layer 130. The buffer layer 325 may function to mitigate internal stress due to the difference in lattice constant between the substrate 110 and the first conductive type nitride semiconductor layer 130. [ Thereby, the first conductivity type nitride semiconductor layer 130 can be epitaxially grown on the buffer layer 325. [ As the buffer layer 325, for example, a known nitride layer such as an aluminum nitride layer, a gallium nitride layer, an aluminum gallium nitride layer, or the like can be applied.

The optical structure 120 may be arranged in a discontinuous pattern structure on the substrate 110 and the buffer layer 325 may be formed to cover the optical structure 120.

In some other embodiments not shown, the buffer layer 325 may be stacked along the pattern of the optical structure 120. The buffer layer 325 can be formed along the shape of the optical structure 120 such that the upper surface of the buffer layer 325 has a vertical bending. The first conductivity type nitride layer 130 and the active layer 140 are formed to have a curved shape as in the first conductivity type nitride layer 230 and the active layer 240 of the light emitting device 200 of FIG. . Accordingly, the area of the active layer 140 can be increased, and the amount of light emitted from the active layer 140 can be increased.

4 is a cross-sectional view schematically showing a light emitting device according to a fourth embodiment of the present invention. 4, the light emitting device 400 has substantially the same configuration as that of the light emitting device 100 according to the first embodiment of FIG. 1 except for the configuration of the substrate 410 and the buffer layer 425 . Therefore, in the following description, configurations differentiated from each other will be described.

The light emitting device 400 includes a patterned sapphire substrate (PSS) 410 as a substrate. Accordingly, the incident light can be scattered on the surface of the patterned sapphire substrate 410, and can be suppressed from being reflected or transmitted through the substrate 410.

A buffer layer 425 may be disposed on the patterned sapphire substrate 410. The buffer layer 425 may function to mitigate the internal stress due to the difference in lattice constant between the substrate 110 and the first conductive type nitride semiconductor layer 130. The buffer layer 425 may have substantially the same configuration as the buffer layer 325 of the third embodiment of FIG.

The optical structure 120 may be disposed on the upper surface of the buffer layer 425. The optical structure 120 may be a pattern structure that is arranged discontinuously. Referring to FIG. 4, the buffer layer 425 may be formed to have a flat top surface on a concave-convex PSS. Thus, the optical structure 120 can be easily placed on a flat surface.

5 is a cross-sectional view schematically showing a light emitting device according to a fifth embodiment of the present invention. 5, the light emitting device 500 includes a light emitting device 100 according to the first embodiment of FIG. 1 except for the configuration of the substrate 410 and the buffer layers 425 and 427, same. The configuration of the light emitting device 500 is the same as that of the fourth embodiment of FIG. 4 except that a buffer layer 427 is additionally disposed on the upper surface of the optical structure. Therefore, in the following description, configurations differentiated from each other will be described.

5, the optical structure 120 is disposed on the first buffer layer 425, and the second buffer layer 427 is further disposed to cover the optical structure 120. As shown in FIG. Thereby, the optical structure 120 may be surrounded by the first and second buffer layers 425 and 427.

The materials of the first buffer layer 425 and the second buffer layer 427 may be the same or different from each other. The first buffer layer 425 and the second buffer layer 427 reduce the internal stress due to the difference in lattice constant between the first conductive type nitride semiconductor layer 130 and the first conductive type nitride semiconductor layer 130, Tex. As the first buffer layer 325 and the second buffer layer 327, a known nitride layer such as an aluminum nitride layer, a gallium nitride layer, an aluminum gallium nitride layer, or the like can be applied.

The second buffer layer 427 is disposed in contact with the first conductive type nitride semiconductor layer 130, thereby effectively reducing the internal stress caused by the difference in the pitch constant. Accordingly, the first conductive type nitride semiconductor layer 130 can be epitaxially grown on the second buffer layer 427 more easily.

6 is a cross-sectional view schematically showing a light emitting device according to a sixth embodiment of the present invention. Referring to FIG. 6, the light emitting device 600 has a structure in which the optical structure 120 is provided inside the first conductive type nitride semiconductor layers 430 and 435.

Referring to the drawings, a light emitting device 600 includes a patterned sapphire substrate 410 as a substrate. Accordingly, the incident light can be scattered on the surface of the patterned sapphire substrate 410, and can be suppressed from being reflected or transmitted through the substrate 410.

A buffer layer 425 may be disposed on the patterned sapphire substrate 410. The buffer layer 425 may function to mitigate the internal stress due to the difference in lattice constant between the substrate 110 and the first conductive type nitride semiconductor layer 130.

The first conductive type first nitride semiconductor layer 430 may be formed on the buffer layer 425. The first conductive type nitride semiconductor layer 430 has substantially the same structure as that of the first conductive type nitride semiconductor layer 130 according to the first embodiment shown in FIG.

The optical structure 120 may be disposed on the first conductive type first nitride semiconductor layer 430. The optical structure 120 may be a pattern structure that is arranged discontinuously.

The first conductive type second nitride semiconductor layer 435 may be disposed to cover the optical structure 120. [ The first conductive type second nitride semiconductor layer 435 may have the same or different material as the first conductive type first nitride semiconductor layer 430. In one example, the first-conductivity-type second layer 435, Al x (the first GaN layer (GaN), aluminum gallium nitride layer doped with n-type or p-type Ga 1 - x N, 0 < (Al x In y Ga 1 -x- y N, 0? x, y, x + y? 1), or a combination of two or more thereof. .

The active layer 140 and the second conductive type nitride semiconductor layer 150 may be sequentially disposed on the first conductive type second nitride semiconductor layer 435.

In this embodiment, the optical structure 120 can be formed so that the optical structure 120 is buried in the first conductive type nitride semiconductor layers 430 and 435. This makes it possible to arrange the optical structure 120 closer to the active layer 140. Accordingly, the light emitted from the active layer 140 can be reflected or scattered by the optical structure 120 before it is dispersed in various paths. As a result, light that is refracted or transmitted in the substrate direction can be blocked more effectively.

7 is a graph showing the reflectance of an optical structure according to an embodiment of the present invention. Referring to FIG. 7, the optical structure according to the embodiment of the present invention is constructed from the first to third embodiments. The optical structure was laminated on a non-patterned sapphire substrate and was made to include a plurality of unit laminated structures. The unit laminate structure was composed of an oxide compound film and an aluminum nitride film. In the optical structure of the first embodiment, the unit laminated structure is laminated in 61 pairs and has a total thickness of 5.35 mu m. In the optical structure of the second embodiment, the unit laminated structure is stacked in 81 pairs, and has a total thickness of 7.27 mu m. In the optical structure of the third embodiment, the unit laminate structure is stacked in 47 pairs, and has a total thickness of 4.12 mu m.

Referring to FIG. 7 again, it can be confirmed that the reflectances of at least 90% and nearly 100% are exhibited for the light of the wavelength range of about 400 to 800 nm, which is the entire visible light region, for the first to third embodiments . Accordingly, it can be seen that the optical structure according to the embodiment of the present invention effectively functions as a reflection structure for the entire wavelength of visible light.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It can be understood that

100 200 300 400 500 600: light emitting element,
110: substrate, 120: optical structure,
130: first conductive type nitride semiconductor layer, 140: active layer,
150: second conductive type nitride semiconductor layer,
160: first electrode layer, 170: second electrode layer,
325: buffer layer, 410: patterned sapphire substrate,
425: first buffer layer, 427: second buffer layer,
430: a first conductive type first nitride semiconductor layer;

Claims (20)

Board;
A first conductive type nitride semiconductor layer, an active layer, and a second conductive type nitride semiconductor layer sequentially stacked on the substrate; And
And an optical structure interposed between the substrate and the active layer and having an aluminum nitride pattern layer
Light emitting element. The method according to claim 1,
The substrate may be any one selected from the group consisting of a patterned sapphire substrate, a silicon carbide substrate, a gallium nitride substrate, an aluminum nitride substrate, and a silicon substrate
Light emitting element. The method according to claim 1,
Wherein the optical structure includes a unit laminated structure composed of an oxidized compound pattern layer and an aluminum nitride pattern layer alternately stacked
Light emitting element. The method of claim 3,
The uppermost pattern layer of the optical structure is the aluminum nitride pattern layer
Light emitting element. The method of claim 3,
The optical structure is formed by stacking 10 to 100 pairs of unit laminate structures having a thickness of 80 to 90 nm
Light emitting element. The method according to claim 1,
The optical structure includes a scattered Bragg reflection layer (DBR) reflecting light incident on the optical structure
Light emitting element. The method according to claim 6,
Wherein the optical structure has a reflectance of at least 90% or more for light having a wavelength range of 400 nm to 800 nm
Light emitting element. The method according to claim 1,
Wherein the optical structure is a pattern structure that is discontinuously arranged on an upper surface of the substrate
Light emitting element. The method according to claim 1,
And a buffer layer disposed between the substrate and the first conductive type nitride semiconductor layer,
The optical structure is a pattern structure that is discontinuously arranged on the upper surface of the buffer layer
Light emitting element. The method according to claim 1,
And a buffer layer disposed between the substrate and the first conductive type nitride semiconductor layer,
The optical structure is a pattern structure that is discontinuously arranged inside the buffer layer
Light emitting element. The method according to claim 1,
The optical structure is a pattern structure that is discontinuously arranged inside the first conductive type nitride semiconductor layer
Light emitting element. An optical structure including an oxide compound pattern layer and an aluminum nitride pattern layer disposed discontinuously on a different substrate and alternately stacked on each other; And
A first conductive type nitride semiconductor layer, an active layer, and a second conductive type nitride semiconductor layer sequentially stacked on the different substrate on which the optical structure is located,
Light emitting element. 13. The method of claim 12,
The dissimilar substrate
The substrate may be any one selected from the group consisting of a patterned sapphire substrate, a silicon carbide substrate, a gallium nitride substrate, an aluminum nitride substrate, and a silicon substrate
Light emitting element. 13. The method of claim 12,
The aluminum nitride pattern layer
And at least one of the first conductivity type nitride semiconductor layer, the active layer, and the second conductivity type nitride semiconductor layer functions as a buffer layer for epitaxial growth
Light emitting element. 13. The method of claim 12,
Wherein the optical structure includes a pair of multi-layers of a unit laminated structure composed of the oxide compound layer and the aluminum nitride layer
Light emitting element. 16. The method of claim 15,
The optical structure is formed by stacking 10 to 100 pairs of unit laminate structures having a thickness of 80 to 90 nm
Light emitting element. 13. The method of claim 12,
Wherein the optical structure has a reflectance of at least 90% or more for light having a wavelength range of 400 nm to 800 nm
Light emitting element. 13. The method of claim 12,
And a buffer layer disposed between the heterojunction substrate and the first conductive type nitride semiconductor layer,
Wherein the optical structure is disposed adjacent to the interface between the heterogeneous substrate and the buffer layer
Light emitting element. 13. The method of claim 12,
And a buffer layer disposed between the heterojunction substrate and the first conductive type nitride semiconductor layer,
The optical structure is disposed in the buffer layer or on the upper surface of the buffer layer
Light emitting element. 13. The method of claim 12,
Wherein the optical structure is disposed inside the first conductive semiconductor layer
Light emitting element.

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017119711A1 (en) * 2016-01-05 2017-07-13 엘지이노텍(주) Semiconductor device
CN113764555A (en) * 2021-07-28 2021-12-07 西安电子科技大学芜湖研究院 AlN ultraviolet light-emitting diode based on nano-pattern insertion layer and preparation method thereof

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017119711A1 (en) * 2016-01-05 2017-07-13 엘지이노텍(주) Semiconductor device
US11355672B2 (en) 2016-01-05 2022-06-07 Suzhou Lekin Semiconductor Co., Ltd. Semiconductor device
CN113764555A (en) * 2021-07-28 2021-12-07 西安电子科技大学芜湖研究院 AlN ultraviolet light-emitting diode based on nano-pattern insertion layer and preparation method thereof
CN113764555B (en) * 2021-07-28 2023-09-01 西安电子科技大学芜湖研究院 AlN ultraviolet light-emitting diode based on nano pattern insertion layer and preparation method thereof

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