KR20170063213A - Light Emitting Device and Method for the same - Google Patents

Abstract

An embodiment includes a conductive base layer; A first insulating layer disposed on the conductive base layer and including a plurality of first holes; A first semiconductor core electrically connected to the conductive base layer through the first hole, an active layer disposed on the first semiconductor core, and a second semiconductor layer disposed on the active layer, And a top surface of the first semiconductor core has a first flat surface, and a method of manufacturing the same.

Description

Technical Field [0001] The present invention relates to a light emitting device,

The embodiments relate to a light emitting device and a manufacturing method thereof.

A light emitting device (LED) is a compound semiconductor device that converts electric energy into light energy. By controlling the composition ratio of the compound semiconductor, various colors can be realized.

The nitride semiconductor light emitting device has advantages of low power consumption, semi-permanent lifetime, fast response speed, safety, and environmental friendliness compared to conventional light sources such as fluorescent lamps and incandescent lamps. Accordingly, a light emitting diode backlight replacing a cold cathode fluorescent lamp (CCFL) constituting a backlight of an LCD (Liquid Crystal Display) display device, a white light emitting diode lighting device capable of replacing a fluorescent lamp or an incandescent lamp, And traffic lights.

Recently, a light emitting device using vertically grown nanostructures has been developed. Such a nanostructure can emit light in all directions, and thus can broaden the light emitting area.

However, the vertically grown nanostructures have a problem in that a large number of leakage current paths are generated inside the nanostructures, resulting in low luminous efficiency.

The embodiment provides a light emitting device capable of reducing a leakage current.

The problems to be solved in the embodiments are not limited to these, and the objects and effects that can be grasped from the solution means and the embodiments of the problems described below are also included.

A light emitting device according to an embodiment of the present invention includes a conductive base layer; A first insulating layer disposed on the conductive base layer and including a plurality of first holes; A first semiconductor core electrically connected to the conductive base layer through the first hole, an active layer disposed on the first semiconductor core, and a second semiconductor layer disposed on the active layer, Structure, wherein an upper portion of the first semiconductor core includes a first planar surface.

And the active layer includes a second flat surface disposed on the first flat surface.

The upper portion of the second semiconductor layer may be pointed more than the upper portion of the first semiconductor core and the active layer.

And a second insulating layer disposed on a side surface of the second semiconductor layer.

The second insulating layer may be disposed at a height of 1/5 to 1/2 of the height of the second semiconductor layer.

According to another embodiment of the present invention, there is provided a light emitting device comprising: a conductive base layer; A first insulating layer disposed on the conductive base layer and including a plurality of first holes; A first semiconductor core electrically connected to the conductive base layer through the first hole, an active layer disposed on the first semiconductor core, and a second semiconductor layer disposed on the active layer, Structure, wherein an upper portion of the first semiconductor core has a different doping concentration from the conductive base layer.

The upper portion of the first semiconductor core may include a u-GaN layer.

A method of manufacturing a light emitting device according to an embodiment of the present invention includes: forming a first insulating layer having a plurality of first holes on a conductive base layer; And growing a light emitting structure including a first semiconductor core, an active layer, and a second semiconductor layer on the first hole, wherein the step of growing the light emitting structure comprises: And the upper portion of the first semiconductor core can be grown flat.

According to another embodiment of the present invention, there is provided a method of manufacturing a light emitting device, comprising: forming a first insulating layer having a plurality of first holes on a conductive base layer; And growing a light emitting structure including a first semiconductor core, an active layer, and a second semiconductor layer on the first hole, wherein the step of growing the light emitting structure comprises: It is possible to prevent the upper portion of the first semiconductor core from being doped by blocking the element.

According to the embodiment, it is possible to manufacture a light emitting device having a reduced leakage current and an excellent luminous efficiency.

The various and advantageous advantages and effects of the present invention are not limited to the above description, and can be more easily understood in the course of describing a specific embodiment of the present invention.

1 is a conceptual diagram of a light emitting device according to an embodiment of the present invention,
2 is a photograph of a conventional light emitting device,
3 is an enlarged view of a portion A in Fig. 1,
Figure 4 is a photograph of the first semiconductor layer core of Figure 1,
FIG. 5 is a photograph of the light emitting structure of FIG. 1,
6 is a conceptual diagram of a light emitting device according to another embodiment of the present invention
7 is a flowchart illustrating a method of manufacturing a light emitting device according to an embodiment of the present invention,
8 is a flowchart illustrating a method of manufacturing a light emitting device according to another embodiment of the present invention.

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

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

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

In the description of the embodiments, in the case where one element is described as being formed "on or under" another element, the upper (upper) or lower (lower) or under are all such that two elements are in direct contact with each other or one or more other elements are indirectly formed between the two elements. Also, when expressed as "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

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

FIG. 1 is a conceptual diagram of a light emitting device according to an embodiment of the present invention, FIG. 2 is a photograph of a conventional light emitting device, FIG. 3 is an enlarged view of a portion A of FIG. 1, And Fig. 5 is a photograph of the light emitting structure of Fig.

1, a light emitting device 100A according to an embodiment includes a conductive base layer 120 disposed on a substrate 110, a plurality of first holes W1 disposed on the conductive base layer 120, And a plurality of light emitting structures 140 electrically connected to the conductive base layer 120 through the first holes W1.

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

The conductive base layer 120 may be formed on the substrate 110 and provide the growth surface of the light emitting structure 140. In addition, the conductive base layer 120 may be electrically conductive to electrically connect the first electrode 171 and the light emitting structure 140.

The conductive base layer 120 may have the same composition as the first semiconductor core 141, but is not limited thereto. The conductive base layer 120 may be doped with an n-type dopant such as Si, Ge, Sn, Se or Te, but is not limited thereto.

The first insulating layer 130 is disposed on the conductive base layer 120. The first insulating layer 130 includes a plurality of first holes W to which the conductive base layer 120 and the light emitting structure 140 are electrically connected. The plurality of first holes W may be formed by a mask pattern. The first insulating layer 130 may include, but is not limited to, an insulating material such as SiO ₂ or SiN x.

The plurality of light emitting structures 140 includes a first semiconductor core 141 electrically connected to the conductive base layer 120 through a first hole W, an active layer 142 formed on the first semiconductor core 141, , And a second semiconductor layer (143) formed on the active layer (142).

The light emitting structure 140 grows in a direction substantially perpendicular to the substrate 110, and may have a nano-sized size. Light emitted from the light emitting structure 140 may be emitted in the direction of the substrate 110 and / or in the opposite direction.

The first semiconductor core 141 may grow on the surface of the conductive base layer 120 exposed by the first hole W. [ The first semiconductor core 141 may be a nano-rod, but is not limited thereto.

The first semiconductor core 141 may be a compound semiconductor such as a III-V group or a II-VI group, and the first semiconductor core 141 may be doped with a first dopant.

The first semiconductor core 141 is a semiconductor material having a composition formula of In _{x 1} Al _{y 1} Ga _{1 -x 1 -y 1} N (0? _{X 1 ? 1} , 0? _{Y 1 ? 1} , 0? _{X 1 + y 1 ? 1} ) GaN, AlGaN, InGaN, InAlGaN, and the like. The first dopant may be an n-type dopant such as Si, Ge, Sn, Se, or Te. When the first dopant is an n-type dopant, the first semiconductor core 141 doped with the first dopant may be an n-type semiconductor.

Referring to FIG. 2, the active layer grown on the pointed core may have a problem that the upper region A is partially broken. The collapsed region forms a first leakage current path. Further, a dislocation existing between the nGaN and the pGaN (B) forms a second leakage current path.

Referring to FIG. 3, the first semiconductor core 141 according to the embodiment may include a first flat surface 141a formed on the upper surface. The method of controlling the upper portion of the first semiconductor core 141 in a flat manner may vary. For example, the upper portion may be controlled to be flat by growing in a nitrogen atmosphere, or may be controlled by mechanical leveling.

The active layer 142 is disposed on the first semiconductor core 141. The active layer 142 includes the second flat surface 142a formed on the first flat surface 141a of the first semiconductor core 141. [ Therefore, the problem that the active layer 142 is sufficiently supported by the first semiconductor core 141 and the active layer 142 is collapsed can be solved.

The active layer 142 is a layer where electrons (or holes) injected through the first semiconductor core 141 and holes (or electrons) injected through the second semiconductor layer 143 meet. As the electrons and the holes are recombined, the active layer 142 transitions to a low energy level and can generate light having a wavelength corresponding thereto. There is no limitation on the emission wavelength in this embodiment.

The active layer 142 may have any one of a single well structure, a multiple well structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum dot structure, Is not limited thereto.

The active layer 142 may have a structure in which a plurality of well layers and barrier layers are alternately arranged. The well layer and the barrier layer may have a composition formula of InxAlyGa1-x-yN (0? X? 1, 0? Y? 1, 0? X + y? 1), and the energy band gap of the barrier layer Band gap.

The second semiconductor layer 143 is disposed on the active layer 142. The second semiconductor layer 143 may be formed of a compound semiconductor such as a III-V group or a II-VI group, and the second semiconductor layer 143 may be doped with a second dopant.

A second semiconductor layer 143 is a semiconductor material having a compositional formula of _{In x5 Al y2 Ga 1 -x5- y2} N (0≤x5≤1, 0≤y2≤1, 0≤x5 + y2≤1) or AlInN, AlGaAs , GaP, GaAs, GaAsP, and AlGaInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, or Ba, the second semiconductor layer 143 doped with the second dopant may be a p-type semiconductor.

An electron blocking layer (EBL) may be disposed between the active layer (142) and the second semiconductor layer (143). The electron blocking layer may be formed of a semiconductor material having a composition formula of In _{x 1} Al _{y 1} Ga _{1 -x 1 -y 1} N (0? _{X 1 ? 1} , 0? _{Y 1 ? 1} , 0? _{X 1 + y 1 ? 1} ), for example, AlGaN, InGaN, InAlGaN, and the like, but is not limited thereto.

A second insulating layer 150 may be disposed on the second semiconductor layer 143. The second insulating layer 150 may block the first leakage current path and / or the second leakage current path. The height h2 of the second insulating layer 150 may be 1/5 to 1/2 of the height h1 of the second semiconductor layer 143. [ If the height h2 of the second insulating layer 150 is less than 1/5 of the thickness of the second semiconductor layer 143, the leakage current path may not be effectively blocked. If the height h2 of the second insulating layer 150 is greater than 1/2 of the second semiconductor layer 143, there is a problem that the light emitting area is excessively reduced.

The conductive layer 160 is disposed on the light emitting structure 140. The conductive layer 160 may electrically connect the second electrode 172 and the second semiconductor layer 143. The first electrode 171 may be disposed on the exposed conductive base layer 120 and electrically connected to the first semiconductor core 141.

The light emitting structure 140 may have various shapes. Depending on the growth conditions, it may include both a pyramid shape, a nanorod shape, and a flat top shape. Referring to FIG. 4, even if the first flat surface 141a is formed on the first semiconductor core 141, the final light emitting structure 140 may have a pyramid shape as shown in FIG.

6 is a conceptual view of a light emitting device according to another embodiment of the present invention.

6, the light emitting device 100B according to the embodiment includes a conductive base layer 120, a first insulating layer (not shown) disposed on the conductive base layer 120 and including a plurality of first holes W1 And a plurality of light emitting structures 140 connected to the conductive base layer 120 through the first holes W1.

The light emitting structure 140 includes a first semiconductor core 141 electrically connected to the conductive base layer 120, an active layer 142 disposed on the first semiconductor core 141, and an active layer 142 disposed on the active layer 142 And the second semiconductor layer 143 is formed. In the present embodiment, the above-described configuration can be applied as it is except for the upper portion 141b of the first semiconductor core 141. [ That is, the general structure of the conductive base layer 120, the first insulating layer 130, the second insulating layer 150, and the light emitting structure may be applied as it is.

The upper portion 141b of the first semiconductor core 141 according to the embodiment may be controlled to have a different doping concentration from the conductive base layer 120. [ In one example, the upper portion 141b of the first semiconductor core 141 may include an undoped u-GaN layer.

According to this structure, even if the upper part of the light emitting structure 140 is collapsed, the conductive part of the first semiconductor core 141 and the second semiconductor layer 143 may not be electrically connected by the u-GaN layer. That is, the upper portion 141b of the first semiconductor core 141 can block the current leakage path. The height at which the upper portion 141b starts may be 1/5 to 1/2 point of the second semiconductor layer 143.

7 is a flowchart illustrating a method of manufacturing a light emitting device according to an embodiment of the present invention.

The method of manufacturing a light emitting device according to an embodiment of the present invention includes the steps of forming a first insulating layer 130 having a plurality of first holes W1 on a conductive base layer 120, A step of growing the light emitting structure 140 including the semiconductor layer 141, the active layer 142, and the second semiconductor layer 143 is performed.

Referring to FIG. 7A, a conductive conductive base layer 120 is formed on a substrate 110. The substrate 110 may be formed of a material selected from the group consisting of sapphire (Al 2 O 3), SiC, GaAs, GaN, ZnO, Si, GaP, InP and Ge.

The conductive base layer 120 may have the same composition as the first semiconductor core 141, but is not limited thereto. The conductive base layer 120 may be doped with an n-type dopant such as Si, Ge, Sn, Se or Te, but is not limited thereto.

Referring to FIG. 7B, a first insulating layer 130 having a plurality of first holes W1 is formed on the conductive base layer 120. Referring to FIG. The first insulating layer 130 may be a variety of insulating materials of _{SiO 2, Si 3 N 4,} Al 2 O 3, ZrSiO 4, HfSiO 4, ZrO 2, HfO 2, La 2 O 3, Ta 2 O 5, TiO 2 And the first hole W1 may be formed to have a width of 0.5 mu m or more and 3 mu m or less, but is not limited thereto.

Referring to FIG. 7C, a plurality of light emitting structures 140 are grown on the first insulating layer 130. The light emitting structure 140 may be grown by any conventional semiconductor growth method. For example, CVD processes such as MOCVD, HVPE, ALD, PECVD, LPCVD and APCVD can all be applied.

The first semiconductor core 141 can be grown on the surface of the conductive base layer 120. [ At this time, the first semiconductor core 141 may be grown in a nitrogen atmosphere to grow the first semiconductor core 141 to have the first flat surface 141a. When grown in a hydrogen and nitrogen atmosphere, a sharp top structure can be formed. When grown in a nitrogen atmosphere, an epitaxial structure having a flat top can be produced.

Thereafter, the active layer 142 and the second semiconductor layer 143 can be sequentially grown. The active layer 142 may grow along the outer surface of the first semiconductor core 141. Therefore, the active layer has the second flat surface 142. At the time of growing the second semiconductor layer 143, the tip can be controlled to be sharp by growing in hydrogen and nitrogen atmosphere.

Referring to FIG. 7D, a second insulating layer 150 may be formed on the light emitting structure 140 and the first insulating layer 130. The height of the second insulating layer 150 can be 1/5 to 1/2 of the height of the second semiconductor layer 143.

Referring to FIG. 7E, the conductive layer 160 covering the light emitting structure 140 may be formed, and the first electrode 171 and the second electrode 172 may be formed.

8 is a flowchart illustrating a method of manufacturing a light emitting device according to another embodiment of the present invention.

The method of manufacturing a light emitting device according to an embodiment of the present invention includes the steps of forming a first insulating layer 130 having a plurality of first holes on a conductive base layer 120 and forming a first semiconductor layer 141 on the first hole, The active layer 142, and the second semiconductor layer 143. The above process can be applied as it is. Hereinafter, the characteristic parts will be mainly described.

Referring to FIG. 8B, the first semiconductor core 141 may be grown on the surface of the conductive base layer 120. At this time, the first semiconductor core 141 can be grown by blocking doping element supply from the upper portion 141b. Therefore, the upper portion 141b of the first semiconductor core 141 may include a u-GaN layer. However, depending on growth conditions, a small amount of doping element may be doped.

8C, the active layer 142 and the second semiconductor layer 143 can be sequentially grown. The active layer 142 may grow along the outer surface of the first semiconductor core 141. According to this structure, even if the top of the light emitting structure collapses, the first semiconductor core 141 and the second semiconductor layer 143 may not be electrically connected by the u-GaN layer. That is, the u-GaN layer can block the current leakage path.

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

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

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

The illumination device includes a light source module including a substrate 110 and the light emitting device of the embodiment, a heat dissipation unit that dissipates heat of the light source module, and a power supply unit that processes or converts the electrical signal provided from the outside and provides the light source module can do. Further, the lighting device may include a lamp, a head lamp, or a street lamp or the like.

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

110: substrate
120: conductive base layer
130: first insulating layer
140: Light emitting structure
141: first semiconductor core
142:
143: second semiconductor layer

Claims (9)

A conductive base layer;
A first insulating layer disposed on the conductive base layer and including a plurality of first holes; And
A plurality of light emitting structures including a first semiconductor core electrically connected to the conductive base layer through the first hole, an active layer disposed on the first semiconductor core, and a second semiconductor layer disposed on the active layer, / RTI >
And an upper portion of the first semiconductor core has a first flat surface.
The method according to claim 1,
And the active layer includes a second flat surface disposed on the first flat surface.
3. The method of claim 2,
Wherein an upper portion of the second semiconductor layer is pointed more than an upper portion of the first semiconductor core and the active layer.
The method according to claim 1,
And a second insulating layer disposed on a side surface of the second semiconductor layer.
5. The method of claim 4,
And the second insulating layer is disposed to a height of 1/5 to 1/2 of a height of the second semiconductor layer.
A conductive base layer;
A first insulating layer disposed on the conductive base layer and including a plurality of first holes; And
A plurality of light emitting structures including a first semiconductor core electrically connected to the conductive base layer through the first hole, an active layer disposed on the first semiconductor core, and a second semiconductor layer disposed on the active layer, / RTI >
Wherein an upper portion of the first semiconductor core has a doping concentration different from that of the conductive base layer.
The method according to claim 6,
And the upper portion of the first semiconductor core includes a u-GaN layer.
Forming a first insulating layer having a plurality of first holes on the conductive base layer; And
And growing a light emitting structure including a first semiconductor core, an active layer, and a second semiconductor layer on the first hole,
The step of growing the light emitting structure includes:
And growing the first semiconductor core in a nitrogen atmosphere to flatten an upper portion of the first semiconductor core.
Forming a first insulating layer having a plurality of first holes on the conductive base layer; And
And growing a light emitting structure including a first semiconductor core, an active layer, and a second semiconductor layer on the first hole,
The step of growing the light emitting structure includes:
Wherein the doping element is cut off during the growth of the first semiconductor core to prevent doping of the upper portion of the first semiconductor core.

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