KR20150096044A - Light emitting device and method for fabricating light emitting device - Google Patents

Abstract

The present invention relates to a light emitting device and a method for fabricating a light emitting device. The light emitting device includes: a substrate having a penetration groove; a first conductivity type semiconductor layer which is filled in the penetration groove and is formed on the upper part of the substrate; an active layer on the first conductivity type semiconductor layer; a second conductivity type semiconductor layer on the active layer; a second electrode formed on the second conductivity type semiconductor layer; and a first electrode which touches the lower part of the first conductivity type semiconductor layer. According to the configuration, the present invention provides a light emitting device capable of improving light efficiency by increasing a surface light emitting area, and a method for fabricating a light emitting device.

Description

TECHNICAL FIELD [0001] The present invention relates to a light emitting device,

The present invention relates to a light emitting device and a manufacturing method of the light emitting device.

BACKGROUND ART Light emitting devices such as a light emitting diode (LED) or a laser diode (LD) using semiconductor materials of Group 3-5 or 2-6 group semiconductors have been developed with thin film growth technology and device materials, Green, blue, and ultraviolet rays. By using fluorescent materials or combining colors, it is possible to realize white light rays with high efficiency. Also, compared to conventional light sources such as fluorescent lamps and incandescent lamps, low power consumption, It has the advantages of response speed, safety, and environmental friendliness.

Since such a light emitting diode does not contain environmentally harmful substances such as mercury (Hg) used in conventional lighting devices such as incandescent lamps and fluorescent lamps, it has excellent environmental friendliness, and has advantages such as long life and low power consumption characteristics. .

The light emitting diode may be replaced with a transmission module of an optical communication means, a light emitting diode backlight replacing a cold cathode fluorescent lamp (CCFL) constituting a backlight of an LCD (Liquid Crystal Display) display device, a fluorescent lamp or an incandescent lamp White LED lightings, automotive headlights and traffic lights.

A conventional semiconductor light emitting device includes a sapphire substrate and an n-type semiconductor layer sequentially formed on the sapphire substrate, an active layer, and a p-type semiconductor layer. Further, the light emitting element includes an n-type electrode and a p-type electrode which are connected to the n-type semiconductor layer and the p-type semiconductor layer, respectively.

In the conventional light emitting device, two electrodes are formed on the surface of the chip, thereby reducing the surface emission area and lowering the light efficiency.

Korean Patent Application No. 10-2009-0132733

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a light emitting device and a method of manufacturing a light emitting device that can increase the light efficiency by increasing the surface light emitting area.

According to an aspect of the present invention, there is provided a light emitting device comprising: a substrate having a through-hole formed therein; A first conductive semiconductor layer formed on the substrate while filling the through hole; An active layer on the first conductive semiconductor layer; A second conductive semiconductor layer on the active layer; A second electrode formed on the second conductive type semiconductor layer; A first electrode formed in contact with a lower portion of the first conductive semiconductor layer; .

The first electrode may include a first insulating layer that is in contact with the substrate and the first conductive type semiconductor layer on one side and a second insulating layer that is spaced apart from the first insulating layer, A second insulating layer to be contacted; An ohmic layer disposed under the first conductive semiconductor layer and in contact with the first conductive semiconductor layer, the first insulating layer, and the second insulating layer; A reflective layer disposed below the ohmic layer and in contact with the ohmic layer, the first insulating layer, and the second insulating layer; A barrier layer of a metal material disposed under the substrate and the reflective layer and in contact with the substrate, the first insulating layer, the second insulating layer, and the reflective layer; .

According to another aspect of the present invention, there is provided a method of manufacturing a light emitting device, including: forming a groove in a substrate; Forming the first conductive type conductive layer on the substrate such that the first conductive type semiconductor layer fills the groove; Forming an active layer on the first conductive semiconductor layer; Forming a second conductive semiconductor layer on the active layer; Forming a second electrode on the second conductive semiconductor layer; Removing the lower portion of the substrate so that a lower portion of the first conductive type semiconductor layer is exposed; Forming a first electrode under the first conductive semiconductor layer; .

The first electrode may include a first insulating layer that is in contact with the substrate and the first conductive type semiconductor layer on one side and a second insulating layer that is spaced apart from the first insulating layer, A second insulating layer to be contacted; An ohmic layer disposed under the first conductive semiconductor layer and in contact with the first conductive semiconductor layer, the first insulating layer, and the second insulating layer; A reflective layer disposed below the ohmic layer and in contact with the ohmic layer, the first insulating layer, and the second insulating layer; A barrier layer of a metal material disposed under the substrate and the reflective layer and in contact with the substrate, the first insulating layer, the second insulating layer, and the reflective layer; .

According to the present invention, it is possible to provide a light emitting device and a method of manufacturing the light emitting device that can increase the surface efficiency of light by improving the light efficiency.

1A to 1E are views sequentially illustrating a method of manufacturing a light emitting device according to an embodiment of the present invention.
2 is a cross-sectional view illustrating a light emitting device according to an embodiment of the present invention.
FIGS. 3A and 3B are plan views illustrating a conventional light emitting device and a light emitting device of the present invention, respectively. FIGS. 3A and 3B show a conventional light emitting device and a light emitting device of the present invention, respectively.
4 is a cross-sectional view illustrating a light emitting device according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements throughout. The same reference numerals in the drawings denote like elements throughout the drawings.

1A to 1E are views sequentially illustrating a method of manufacturing a light emitting device according to an embodiment of the present invention. 2 is a cross-sectional view illustrating a light emitting device according to an embodiment of the present invention.

Referring to FIG. 1A, first, a through hole 111 (or a groove) is formed in a substrate 110. For example, sapphire (Al ₂ O ₃ ), GaN, SiC, ZnO, Si, GaP, InP, Ga ₂ O ₃ , GaAs, or the like may be used as the substrate 110. The depth of the through-hole 111 may be 10 to 1200 占 퐉. The width of the through-hole 111 may be 50 to 5000 占 퐉.

Next, as shown in FIG. 1B, the first conductive semiconductor layer 120 is formed on the substrate 110 while filling the through-holes 111 formed in the substrate 110. Next, as shown in FIG.

The first conductivity type semiconductor layer 120 may be a semiconductor having a composition formula of In _x Al _y Ga _{1 -x- y} N (where 0? _X? 1, 0? _Y? 1, 0? _X + y? 1) A material such as GaN, AlN, AlGaN, InGaN, InN, InAlGaN or the like and an n-type dopant such as Si, Ge, Sn, Se or Te can be doped. For example, the first conductivity type semiconductor layer 120 may be a GaN layer doped with an n-type dopant.

Next, the active layer 130 is formed on the first conductivity type semiconductor layer 120. The active layer 130 is formed of a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (where 0? _X? 1, 0? _Y? 1, 0? _X + y? 1) And may include at least one of a quantum wire structure, a quantum dot structure, a single quantum well structure or a multi quantum well structure (MQW). For example, the active layer 130 may be formed of an InGaN / GaN layer having an MQW structure.

The active layer 130 generates light by energy generated in the recombination process of electrons and holes provided from the first conductivity type semiconductor layer 120 and the second conductivity type semiconductor layer 140.

Next, a second conductivity type semiconductor layer 140 is formed on the active layer 130. The second conductivity type semiconductor layer 140 is a semiconductor having a composition formula of In _x Al _y Ga _{1 -x- y} N (where 0? _X? 1, 0? _Y? 1, 0? _X + y? 1) For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN and the like, and p-type dopants such as Mg, Zn, Ca, Sr and Ba can be doped. For example, the p-type semiconductor layer 150 may be a GaN layer doped with a p-type dopant.

Next, as shown in FIG. 1C, a second electrode 150 is formed on the second conductive type semiconductor layer 140. The second electrode 150 may be a p-type electrode.

Next, as shown in FIG. 1D, the lower portion of the substrate 110 is removed by lapping so that the lower portion of the first conductivity type semiconductor layer 120 filled in the through hole 111 of the substrate 110 is exposed.

Next, as shown in FIG. 1E, a first electrode 160 is formed under the first conductive semiconductor layer 120. The first electrode 160 may be an n-type electrode.

Next, a heat treatment process, a baking process, and a dicing process may be added to the electrode.

FIG. 2 illustrates a light emitting device manufactured according to the method of manufacturing a light emitting device shown in FIGS. 1A to 1E. The light emitting device 100 includes a substrate 110, a first conductive semiconductor layer 120, an active layer 130, a second conductive semiconductor layer 140, a second electrode 150, a first electrode 160, .

A through hole 111 is formed in the substrate 110. The first conductive semiconductor layer 120 is formed on the substrate 110 while filling the through holes 111. The active layer 130 and the second conductive semiconductor layer 140 are sequentially formed on the first conductive semiconductor layer 120. A second electrode 150 is formed on the second conductive semiconductor layer 140. The first electrode 160 is formed in contact with the lower portion of the first conductive semiconductor layer 120.

FIGS. 3A and 3B are plan views illustrating a conventional light emitting device and a light emitting device of the present invention, respectively. FIGS. 3A and 3B show a conventional light emitting device and a light emitting device of the present invention, respectively.

As shown in FIG. 3A, in the conventional light emitting device, two electrodes are located on the surface of the light emitting device, and the total area of the light emitting device is reduced due to the area occupied by the electrodes, thereby lowering the luminous efficiency.

The light emitting device 100 of the present invention shown in FIG. 3B has one electrode and a second electrode 150 on a surface thereof and the first electrode 160 is located on a bottom surface of the light emitting device 100. Accordingly, only one second electrode 150 is disposed on the surface of the light emitting device 100, thereby increasing the light emitting area of the light emitting device 100, thereby improving the light emitting efficiency. In addition, the manufacturing process of the light emitting device 100 is simplified, thereby facilitating fabrication and reducing the cost.

4 is a cross-sectional view illustrating a light emitting device according to another embodiment of the present invention.

The light emitting device 200 includes a substrate 210, a first conductive semiconductor layer 220, an active layer 230, a second conductive semiconductor layer 240, a second electrode 250, a first electrode 260, . The substrate 210, the first conductivity type semiconductor layer 220, the active layer 230, the second conductivity type semiconductor layer 240, and the second electrode 250 are formed on the substrate 110, Type semiconductor layer 120, the active layer 130, the second conductivity type semiconductor layer 140, and the second electrode 150, detailed description thereof will be omitted.

In this embodiment, the detailed structure is added to the first electrode 260 that is in contact with the first conductivity type semiconductor layer 220 to improve the function of the light emitting device 200.

The first electrode 260 includes insulating layers 261 a and 261 b, an ohmic layer 262, a reflective layer 263, and a barrier layer 264.

The insulating layer includes a first insulating layer 261a contacting the first substrate 210 and the first conductive semiconductor layer 220 and a second insulating layer 261b spaced from the first insulating layer 261a, And a second insulating layer 261b that is in contact with the one conductivity type semiconductor layer 220. The upper surfaces of the insulating layers 261a and 261b are in contact with the first conductive semiconductor layer 220 and the side surfaces thereof are in contact with the barrier layer 264 and the ohmic layer 262. The lower surface is in contact with the barrier layer 264, The reflective layer 262 and the reflective layer 263. The thickness of the insulating layers 261a and 261b may be 2 to 2000 nm.

The insulating layers 261a and 261b prevent the reflection layer 263 disposed below the ohmic layer 262 from contacting the first conductive semiconductor layer 220 to improve the reliability of the light emitting device 200. [

The insulating layers 261a and 261b may be made of a transparent material having a light transmittance of 80% or more. Accordingly, light emitted from the active layer 230 can be reflected by the reflective layer 263 without being absorbed by the insulating layers 261a and 261b, thereby improving the luminous efficiency.

The ohmic layer 262 is disposed under the first conductive semiconductor layer 220 and is in contact with the first conductive semiconductor layer 220, the first insulating layer 261a, and the second insulating layer 261b. The ohmic layer 262 is disposed between the reflective layer 263 and the first conductive semiconductor layer 220. The ohmic layer 262 is ohmic contacted with the first conductivity type semiconductor layer 220 to supply power from the first electrode 260 to the first conductivity type semiconductor layer 220 smoothly.

For example, the ohmic layer 262 may include at least one of In, Zn, Sn, Ni, Pt, and Ag. Further, the ohmic layer 262 can selectively use a light-transmitting conductive layer and a metal. For example, the ohmic layer 262 may include at least one of ITO (indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tin oxide), IAZO (indium aluminum zinc oxide), IGZO tin oxide, AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IrOx, RuOx, RuOx / ITO, Ni, Ag, Ni / IrOx / Au, ITO, and may be implemented as a single layer or multiple layers.

A reflective layer 263 is disposed under the ohmic layer 262 and is in contact with the ohmic layer 262, the first insulating layer 261a, and the second insulating layer 261b. Also, the reflective layer 263 is disposed on the barrier layer 264. [ The reflective layer 263 is composed of two or more spaced apart reflective layers and both ends of the reflective layer 263 may be in contact with the first and second insulating layers 261a and 261b, respectively. The reflective layer 263 reflects light incident from the first conductivity type semiconductor layer 220 to improve light extraction efficiency of the light emitting device 200. For example, the reflective layer 263 may be formed of a metal containing at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au and Hf or an alloy thereof.

The reflective layer 263 may be formed of a metal or an alloy of indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide A transparent conductive material such as AZO (aluminum zinc oxide), ATO (antimony tin oxide), or the like. For example, the reflective layer 263 may be formed of IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag /

The barrier layer 264 is disposed below the substrate 210 and the reflective layer 263 and is in contact with the substrate 210, the first insulating layer 261a, the second insulating layer 261b, and the reflective layer 263. For example, the barrier layer 264 may include at least one of Ni, Pt, Ti, W, V, Fe and Mo and may be a single layer or a multilayer.

The light emitting device 200 of the present embodiment is configured such that the first electrode 260 includes the insulating layers 261a and 261b, the ohmic layer 262, the reflective layer 263, and the barrier layer 264, The object of improving the reliability and improving the light emitting efficiency can be achieved.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention will be.

100: Light emitting element
110: substrate
120: a first conductivity type semiconductor layer
130: active layer
140: second conductive type semiconductor layer
150: second electrode
160: first electrode
261a, 261b: insulating layer
262:
263: Reflective layer
264: barrier layer

Claims (4)

A substrate having a through-hole formed therein;
A first conductive semiconductor layer formed on the substrate while filling the through hole;
An active layer on the first conductive semiconductor layer;
A second conductive semiconductor layer on the active layer;
A second electrode formed on the second conductive type semiconductor layer;
A first electrode formed in contact with a lower portion of the first conductive semiconductor layer;
. The method according to claim 1,
Wherein the first electrode comprises:
A first insulating layer in contact with the substrate and the first conductive type semiconductor layer on one side; a second insulating layer spaced apart from the first insulating layer and contacting the substrate on the other side and the first conductive type semiconductor layer;
An ohmic layer disposed under the first conductive semiconductor layer and in contact with the first conductive semiconductor layer, the first insulating layer, and the second insulating layer;
A reflective layer disposed below the ohmic layer and in contact with the ohmic layer, the first insulating layer, and the second insulating layer;
A barrier layer of a metal material disposed under the substrate and the reflective layer and in contact with the substrate, the first insulating layer, the second insulating layer, and the reflective layer;
. A method of manufacturing a light emitting device,
Forming a groove in the substrate;
Forming the first conductive type conductive layer on the substrate such that the first conductive type semiconductor layer fills the groove;
Forming an active layer on the first conductive semiconductor layer;
Forming a second conductive semiconductor layer on the active layer;
Forming a second electrode on the second conductive semiconductor layer;
Removing the lower portion of the substrate so that a lower portion of the first conductive type semiconductor layer is exposed;
Forming a first electrode under the first conductive semiconductor layer;
Emitting device. The method of claim 3,
Wherein the first electrode comprises:
A first insulating layer in contact with the substrate and the first conductive type semiconductor layer on one side; a second insulating layer spaced apart from the first insulating layer and contacting the substrate on the other side and the first conductive type semiconductor layer;
An ohmic layer disposed under the first conductive semiconductor layer and in contact with the first conductive semiconductor layer, the first insulating layer, and the second insulating layer;
A reflective layer disposed below the ohmic layer and in contact with the ohmic layer, the first insulating layer, and the second insulating layer;
A barrier layer of a metal material disposed under the substrate and the reflective layer and in contact with the substrate, the first insulating layer, the second insulating layer, and the reflective layer;
Emitting device.

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