WO2009035218A2

WO2009035218A2 - Gan-based light emitting diode and method for fabricating the same

Info

Publication number: WO2009035218A2
Application number: PCT/KR2008/004800
Authority: WO
Inventors: Jae-Eung Oh
Original assignee: Wooree Lst Co., Ltd.
Priority date: 2007-09-14
Filing date: 2008-08-19
Publication date: 2009-03-19
Also published as: KR100889569B1; WO2009035218A3; KR20090028229A

Abstract

There are provided a GaN-based light emitting diode (LED) capable of minimizing the structural defect of the GaN-based LED when a substrate is separated from the GaN-based LED and of maximizing light extraction efficiency and a method of fabricating the same. The method of fabricating the GaN-based LED may include forming a plurality of scattering inducing patterns separated from each other at uniform intervals on a substrate, growing a GaN-based semiconductor layer formed of a plurality of layers on an entire surface of the substrate including the scattering inducing patterns, removing the scattering inducing patterns to form scattering inducing grooves in the GaN-based semiconductor layer, and separating the substrate from the GaN-based semiconductor layer by a laser lift off (LLO) method in a state where the scattering inducing patterns are removed.

Description

GAN-BASED LIGHT EMITTING DIODE AND METHOD FOR FABRICATING THE SAME

Technical Field

[1] The present invention relates to a GaN-based light emitting diode (LED) and a method of fabricating the same, and more particularly, to a GaN-based LED capable of minimizing the structural defect of the GaN-based LED when a substrate is separated from the GaN-based LED and of maximizing light extraction efficiency and a method of fabricating the same. Background Art

[2] A light emitting diode (hereinafter, referred to as LED) is a semiconductor device that converts current into light. Since a red LED using GaAsP compound semiconductor was commercialized in 1962, a GaP:N based green LED has been used as the display light source of an electronic device such as an information communication device.

[3] Recently, an LED using GaN-based compound semiconductor is gaining spotlight.

This is because semiconductor layers that emit green, blue, and white light components can be fabricated by combining GaN with such elements as In and Al. The GaN-based LED is widely used for various fields such as flat panel displays (FPDs), traffic lights, indoor lightings, high resolution output systems, and optical communications.

[4] On the other hand, the GaN-based LED is generally fabricated by the following processes. After forming the GaN-based LED by performing processes of growing a GaN-based epitaxial layer and of forming electrodes on a sapphire (Al O ) substrate, the sapphire substrate is separated from the GaN-based LED to complete the GaN- based LED.

[5] In fabricating the conventional GaN-based LED, the sapphire substrate is advantageous in that it is chemically and thermally stable, has a high melting point so that a high temperature fabricating process can be performed, and has a high dielectric constant. IHbwever, because the thermal conductivity of the sapphire substrate is low, it is difficult to fabricate the GaN-based LED of high brightness.

[6] In addition, in fabricating the conventional GaN-based LED, the process of separating the sapphire substrate from the GaN-based LED is required. In order to ensure the characteristics of the GaN-based LED stably, the generation of the cracks of the GaN-based LED must be minimized when the sapphire substrate is separated from the GaN-based LED.

[7] As a method of separating the sapphire substrate from the GaN-based LED, in a conventional art, a laser lift off (LLO) method of radiating laser onto an interface between the sapphire substrate and the epitaxial layer of the GaN-based LED to separate the sapphire substrate from the GaN-based LED is used. The LLO method is presented in the US Patent No. 6,455,340 (Method of fabricating GaN semiconductor structures using laser-assisted epitaxial lift off), the US Patent No. 6,562,648 (Structure and method for separation and transfer of semiconductor thin films onto dissimilar substrate materials), and the US Patent No. 6,071,795 (Separation of thin films from transparent substrates by selective optical processing). IHbwever, the LLO method has a problem in that the epitaxial layer of the GaN-based LED deteriorates due to the high-temperature heat of the laser or in that cracks are generated in the epitaxial layer due to the difference of thermal expansion coefficients.

[8] On the other hand, in order to overcome the low thermal conductivity characteristic of sapphire, researches on applying an SiC substrate or an Si substrate instead of the sapphire substrate are performed. IHbwever, since the SiC substrate is expensive, productivity decreases. The Si substrate is cheap and has an excellent thermal conductivity characteristic. IHbwever, as the thickness of the epitaxial layer increases, the cracks generated due to the difference in the thermal expansion coefficients increase. Disclosure of Invention Technical Problem

[9] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a GaN-based light emitting diode (LED) capable of minimizing the structural defect of the GaN-based LED when a substrate is separated from the GaN-based LED and of maximizing light extraction efficiency and a method of fabricating the same. Technical Solution

[10] In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a method of fabricating a GaN-based light emitting diode (LED). The method can include forming a plurality of scattering inducing patterns separated from each other at uniform intervals on a substrate, growing a GaN-based semiconductor layer formed of a plurality of layers on the entire surface of the substrate including the scattering inducing patterns, removing the scattering inducing patterns to form scattering inducing grooves in the GaN-based semiconductor layer, and separating the substrate from the GaN -based semiconductor layer by an LLO method in the state where the scattering inducing patterns are removed.

[11] lorning the plurality of scattering inducing patterns can include laminating a scattering inducing layer on the substrate and patterning the scattering inducing layer at uniform intervals to form the plurality of scattering inducing patterns.

[12] The substrate can be formed of one of a silicon (Si) substrate, a GaAs substrate, an

MgO substrate, a sapphire (Al O ) substrate, and an SiC substrate or a template substrate obtained by laminating one of GaN, InGaN, AlGaN, and AlInGaN on one of the above substrates.

[13] The scattering inducing layer can be formed of a dielectric material or a metal. The height and the width of the scattering inducing patterns and the distance between the scattering inducing patterns can be smaller than the wavelength of light generated from the GaN-based semiconductor layer. Here, the height and the width of the scattering inducing patterns and the distance between the scattering inducing patterns can be from about 0.1 μm to about 5 μm.

[14] Growing the GaN-based semiconductor layer can include sequentially forming a buffer layer, an n-type contact layer, an n-type clad layer, a light emitting layer, a p- type clad layer, and a p-type contact layer on the entire surface of the substrate including the scattering inducing patterns.

[15] lorning a transparent electrode and a p-electrode on the entire surface of the GaN- based semiconductor layer and forming an n-electrode on the entire surface of the lower surface of the GaN-based semiconductor layer including the scattering inducing grooves can be further included after separating the substrate from the GaN-based semiconductor layer.

[16] In addition, forming a reflection plate and a p-electrode on an entire surface of the

GaN-based semiconductor layer, removing a partial region of the GaN-based semiconductor layer, and forming an n-electrode on the exposed surface of the GaN-based semiconductor layer can be further included after separating the substrate from the GaN-based semiconductor layer. The part from which the partial region is removed can include the p-type clad layer and the light emitting layer and the GaN-based semiconductor the surface of which is exposed can be the n-type clad layer.

[17] Here, when the p-electrode is formed on the upper surface of the GaN-based semiconductor layer before attaching the separation supplementary plate, only processes of forming the transparent electrode and the n-electrode can be performed. In addition, a reflection electrode can be formed instead of the transparent electrode and the p- electrode and the n-electrode may not be formed sequentially.

[18] In accordance with another aspect of the present invention, a method of fabricating a

GaN-based LED can include forming a plurality of scattering inducing patterns separated from each other at uniform intervals on a substrate, growing a GaN-based semiconductor layer formed of a plurality of layers on the entire surface of the substrate including the scattering inducing patterns, separating the substrate from the GaN-based semiconductor layer by an LLO method, and removing the scattering inducing patterns to form scattering inducing grooves in the GaN-based semiconductor layer.

[19] lorning a transparent electrode and a p-electrode on an entire surface of the GaN- based semiconductor layer and forming an n-electrode on an entire surface of the lower surface of the GaN-based semiconductor layer including the scattering inducing grooves can be further included after forming the scattering inducing grooves in the GaN-based semiconductor layer.

[20] In addition, after forming the scattering inducing grooves in the GaN-based semiconductor layer, a reflection plate and a p-electrode can be further provided on the entire surface of the GaN-based semiconductor layer and an n-electrode can be further provided on a surface of the GaN-based semiconductor layer exposed by removing a partial region of the GaN-based semiconductor layer. At this time, the part from which the partial region is removed can include the p-type clad layer and the light emitting layer and the GaN-based semiconductor layer the surface of which is exposed can be the n-type clad layer.

[21] In accordance with still another aspect of the present invention, a GaN-based LED includes a GaN-based semiconductor layer formed of a plurality of layers. A scattering inducing unit for scattering light generated from the GaN-based semiconductor layer can be provided at a lower end of the GaN-based semiconductor layer. The scattering inducing unit can include a plurality of scattering inducing grooves formed to be separated from each other at uniform intervals on a lower surface of the GaN-based semiconductor layer. The GaN-based semiconductor layer can be provided on a substrate.

[22] The height and the width of the scattering inducing grooves and the distance between the scattering inducing grooves can correspond to the wavelength of light generated from the GaN-based semiconductor layer. The height and the width of the scattering inducing grooves and the distance between the scattering inducing grooves can be from about 0.1 /M to about 5 /M, respectively.

[23] In addition, the GaN-based semiconductor layer can have a structure in which a buffer layer, an n-type contact layer, an n-type clad layer, a light emitting layer, a p- type clad layer, and a p-type contact layer are sequentially laminated.

[24] A transparent electrode and a p-electrode can be further provided on the entire surface of the GaN-based semiconductor layer, and an n-electrode can be further provided on the entire surface of the lower surface of the substrate. Alternatively, a reflection plate and a p-electrode can be further provided on the entire surface of the GaN-based semiconductor layer, and an n-electrode can be further provided on the surface of the GaN-based semiconductor layer exposed by removing a partial region of the GaN-based semiconductor layer. The part from which the partial region is removed can include the p-type clad layer and the light emitting layer. The GaN-based semiconductor layer the surface of which is exposed can be the n-type clad layer.

[25] The substrate can be formed of one of the Si substrate, the GaAs substrate, the MgO substrate, and the sapphire (Al O ) substrate or the template substrate obtained by laminating one of GaN, InGaN, AlGaN, and AlInGaN on one of the above substrates.

Advantageous Effects

[26] The GaN-based LED and the method of fabricating the same according to the present invention have the following advantageous effects.

[27] Since the plurality of scattering inducing grooves are provided under the GaN-based semiconductor layer, the light generated by the light emitting layer can be effectively scattered so that light extraction efficiency can be improved.

[28] In addition, since the scattering inducing patterns are formed on the substrate and the scattering inducing patterns are removed when the substrate is separated from the GaN-based semiconductor layer, the substrate can be easily separated from the GaN- based semiconductor layer and the generation of the defect of the GaN-based semiconductor layer can be minimized when the substrate is separated from the GaN-based semiconductor layer. Brief Description of the Drawings

[29] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[30] FIG. 1 is a sectional view illustrating a GaN-based LED according to a first embodiment of the present invention; [31] FIG. 2 is a sectional view illustrating a GaN-based LED according to a second embodiment of the present invention; and

[32] FIGs. 3 to 9 are sectional views illustrating a method of fabricating a GaN-based

LED according to an embodiment of the present invention. Mode for the Invention

[33] Hereinafter, a GaN-based light emitting diode (LED) according to an embodiment of the present invention and a method of fabricating the same will be described in detail with reference to the accompanying drawings.

[34] FIG. 1 is a sectional view illustrating a GaN-based LED according to a first embodiment of the present invention. FIG. 2 is a sectional view illustrating a GaN- based LED according to a second embodiment of the present invention. FIG. 1 illustrates a vertical type GaN-based LED and FIG. 2 illustrates a flip chip type GaN- based LED.

[35] Hrst, as illustrated in FIGs. 1 and 2, the vertical type GaN-based LED and the flip chip type GaN-based LED commonly include a GaN-based semiconductor layer 110 formed of a plurality of layers and a scattering including unit 120 is provided at a lower end of the GaN-based semiconductor layer 110. Here, the scattering induction refers to scattering the light generated from a light emitting layer which is one of a plurality of layers of which the GaN-based semiconductor layer 110 is formed. In order to induce the scattering of the light, the scattering inducing unit 120 in which scattering inducing grooves 122 are formed at uniform intervals is provided at the lower end of the GaN-based semiconductor layer 110.

[36] In order to effectively induce the scattering of the light, the distance between the scattering inducing grooves 122 and the depth and the width of the scattering inducing grooves 122 can be designed to correspond to the wavelength of the light generated from the light emitting layer. Even when the distance between the scattering inducing grooves 122 and the depth and the width of the scattering inducing grooves 122 are designed to be smaller or larger than the wavelength of the light, the scattering characteristic is improved due to reflection. In an embodiment, the distance between the scattering inducing grooves 122 and the depth and the width of the scattering inducing grooves 122 can be designed to be from about 0.1 /M to about 5 /M.

[37] As described above, the GaN-based semiconductor layer 110 is formed of the plurality of layers. Basically, an n-type clad layer 111, a light emitting layer 112, and a p-type clad layer 113 that are sequentially laminated are provided. Although not shown in the drawings, an n-type contact layer and a buffer layer can be further provided under the n-type clad layer 111 and a p-type contact layer can be further provided on the p-type clad layer 113. The buffer layer, the n-type contact layer, the n-type clad layer 111, the light emitting layer 112, the p-type clad layer 113, and the p-type contact layer can be formed of a material having the general formula In (Al Ga )N (0 < x < 1, x y 1-y

0 < y < 1). In addition, impurities such as Si and Mg can be added to the n-type contact layer, the n-type clad layer 111, the p-type clad layer 113, and the p-type contact layer to provide conductivity. Ibr example, Si can be added as impurities to the n-type contact layer and the n-type clad layer 111 and Mg can be added as impurities to the p- type clad layer 113 and the p-type contact layer.

[38] The vertical type GaN-based LED and the flip chip type GaN-based LED according to an embodiment of the present invention have the same structure as described above. That is, the GaN-based semiconductor layer 110 formed of the plurality of layers is provided and the scattering inducing unit 120 is provided at the lower end of the GaN- based semiconductor layer 110. Fbwever, the vertical type GaN-based LED and the flip chip type GaN-based LED according to an embodiment of the present invention have the following differences.

[39] As illustrated in FIG. 1, the vertical type GaN-based LED according to an embodiment of the present invention includes a transparent electrode 103 and a p- electrode 102 on the entire surface of the GaN-based semiconductor layer 110 and the transparent electrode 103 and the p-electrode 102 are electrically connected to each other.

[40] A substrate 301 is provided on the lower surface of the GaN-based semiconductor layer 110. The substrate 301 can be formed of one of a silicon (Si) substrate, a GaAs substrate, an MgO substrate, and a sapphire (Al O ) substrate or a template substrate obtained by laminating one of GaN, InGaN, AlGaN, and AlInGaN on one of the above substrates.

[41] In addition, an n-electrode 101 is provided on the entire surface of the lower surface of the substrate 301. Here, a reflection electrode can be provided instead of the transparent electrode.

[42] As illustrated in FIG. 2, in the flip chip type GaN-based LED according to an embodiment of the present invention, a reflection layer 203 is provided on the entire surface of the GaN-based semiconductor layer 110 and a p-electrode 202 is provided on one side of the GaN-based semiconductor layer 110. In addition, a partial region of the GaN-based semiconductor layer 110 is removed and an n-electrode 201 is provided on the exposed surface of the GaN-based semiconductor layer 110. Here, the part from which the partial region is removed includes the p-type clad layer 113 and the light emitting layer 112 among the plurality of layers of which the GaN-based semiconductor layer 110 is formed and the GaN-based semiconductor layer 110 the surface of which is exposed is the n-type clad layer 111.

[43] In addition, the substrate 301 is provided on the lower surface of the GaN-based semiconductor layer 110. The substrate 301 can be formed of one of the Si substrate, the GaAs substrate, the MgO substrate, and the sapphire (Al O ) substrate or the template substrate obtained by laminating one of GaN, InGaN, AlGaN, and AlInGaN on one of the above substrates.

[44]

[45] A method of fabricating the GaN-based LED according to an embodiment of the present invention having the above structure will be described as follows. FIGs. 3 to 9 are sectional views illustrating the method of fabricating the GaN-based LED according to an embodiment of the present invention.

[46] Hrst, as illustrated in FIG. 3, a substrate is provided. The substrate 301 is for providing the growth space of the GaN-based semiconductor layer 110, and can be formed of the Si substrate, the GaAs substrate, the MgO substrate, and the sapphire (Al O ) substrate or the template substrate obtained by laminating one of GaN, InGaN, AlGaN, and AlInGaN on one of the above substrates.

[47] Then, a scattering inducing layer 121 is laminated on the substrate 301. The scattering inducing layer 121 can be formed of a material having high etching selectivity compared to the GaN-based semiconductor layer 110 laminated by the following processes. For example, the scattering inducing layer 121 can be formed of a dielectric material such as silicon oxide and silicon nitride or a metal.

[48] Subsequently, as illustrated in FIG. 4, the scattering inducing layer 121 is selectively patterned using a photolithography process and an etching process to form a plurality of scattering inducing patterns 121a. At this time, the height and the width of the scattering inducing patterns 121a and the distance between the scattering inducing patterns 121a can be designed to correspond to the wavelength of the light generated from the light emitting layer 112 of the GaN-based semiconductor layer 110 laminated by the following processes. For example, when the wavelength of the light generated from the light emitting layer 112 is from about 0.3 μm to about 0.5 μm, the height and the width of the scattering inducing patterns 121a and the distance between the scattering inducing patterns 121a can be from about 0.1 μm to about 5 μm.

[49] Then, as illustrated in FIG. 5, the GaN-based semiconductor layer 110 is epitaxially grown on the entire surface of the substrate 301 including the plurality of scattering inducing patterns 121a. The GaN-based semiconductor layer 110 can be divided into a plurality of layers and the plurality of layers are obtained by sequentially laminating the buffer layer, the n-type contact layer, the n-type clad layer 111, the light emitting layer 112, the p-type clad layer 113, and the p-type contact layer. Here, the buffer layer, the n-type contact layer, and the p-type contact layer are not shown. In addition, the layers of which the GaN-based semiconductor layer 110 is formed are grown by a metal organic chemical vapor deposition (MOCVD) method or a molecular beam epitaxy (MBE) method. At this time, depending on the growth thickness of the buffer layer, the n-type contact layer, and the n-type clad layer 111, the upper surfaces of the scattering inducing patterns 121a contact one of the buffer layer, the n-type contact layer, and the n-type clad layer 111.

[50] After the GaN-based semiconductor layer 110 is formed, as illustrated in FIG. 6, a separation supplementary plate 302 can be attached onto the upper surface of the GaN- based semiconductor layer 110 using an adhesive (not shown) such as glue and epoxy.

[51] On the other hand, before attaching the separation supplementary plate 302 onto the upper surface of the GaN-based semiconductor layer 110, a p-electrode can be formed in advance on the upper surface of the GaN-based semiconductor layer 110. The p- electrode corresponds to the p-electrode of the vertical type GaN-based LED or the flip chip type GaN-based LED. As described above, when the p-electrode is formed before separating the substrate 301 from the GaN-based semiconductor layer 110 (refer to FIG. 8 and description thereabout given below), only the process of forming an n- electrode needs to be performed after separating the substrate 301 from the GaN-based semiconductor layer 110 by the following processes.

[52] After the separation supplementary plate 302 is attached onto the upper surface of the

GaN-based semiconductor layer 110, as illustrated in FIG. 7, the scattering inducing patterns 121a are removed by performing wet etching. As a result, the adhesive force between the GaN-based semiconductor layer 110 and the substrate 301 decreases. The parts from which the scattering inducing patterns 121a are removed are referred to as the scattering inducing grooves 122.

[53] Then, as illustrated in FIG. 8, the substrate 301 is separated from the GaN-based semiconductor layer 110 using the LLO method. In the conventional LLO method, laser is irradiated onto the entire surface of the interface between the substrate 301 and the GaN-based semiconductor layer 110 so that a crack is generated in the GaN-based semiconductor layer 110 due to the high-output laser. Fbwever, according to the present invention, since the scattering inducing patterns 121a are removed, the substrate 301 can be separated from the GaN-based semiconductor layer 110 with low- output laser and thermal shock caused by the laser can be minimized. That is, the parts from which the scattering inducing patterns 121a are removed restrict thermal transmission, so that the generation of the defect of the GaN-based semiconductor layer 110 is minimized. Ibr reference, although it is described that the LLO method is performed after removing the scattering inducing patterns 121a, the scattering inducing patterns 121a can be removed after performing the LLO method.

[54] Subsequently, as the separation supplementary plate 302 is removed and the following processes for the vertical type GaN-based LED or the flip chip type GaN- based LED are performed, the method of fabricating the GaN-based LED according to an embodiment of the present invention is completed.

[55] In order to fabricate the vertical type GaN-based LED, after the substrate 301 is separated from the GaN-based semiconductor layer 110 and the separation supplementary plate 302 is removed by the processes of FIG. 8, as illustrated in FIG. 9 (a), processes of forming the transparent electrode 103, the p-electrode 102, and the n- electrode 101 can be performed. At this time, as described above, when the p-electrode 102 is formed on the upper surface of the GaN-based semiconductor layer 110 before attaching the separation supplementary plate 302, only the process of forming the transparent electrode 103 and the n-electrode 101 is performed. To be specific, the transparent electrode 103 and the p-electrode 102 are formed on the upper surface of the GaN-based semiconductor layer 110 and the n-electrode 101 is formed on the entire surface of the lower surface of the GaN-based semiconductor layer 110 including the scattering inducing grooves 122 to complete the vertical type GaN-based LED. Here, a reflection electrode can be formed instead of the transparent electrode. In addition, the formation of the p-electrode 102 and the n-electrode 101 needs not be sequential in time. That is, either the p-electrode 102 or the n-electrode 101 can be formed first.

[56] On the other hand, in order to fabricate the flip chip type GaN-based LED, after the substrate 301 is separated from the GaN-based semiconductor layer 110 and the separation supplementary plate 302 is removed by the processes of FIG. 8, as illustrated in FIG. 9 (b), processes of forming the reflection layer 203, the p-electrode 202, and the n-electrode 201 are performed. At this time, when the p-electrode 202 is formed on the upper surface of the GaN-based semiconductor layer 110 before attaching the separation supplementary plate 302, only the process of forming the reflection layer 203 and the n-electrode 201 is performed. To be specific, with the formation of the reflection layer 203 and the p-electrode 202 on the upper surface of the GaN-based semiconductor layer 110, a partial region of the GaN-based semiconductor layer 110 is removed and the n-electrode 201 is formed on the exposed surface of the GaN-based semiconductor layer 110. Here, the part from which the partial region is removed includes the p-type clad layer 113 and the light emitting layer 112 among the plurality of layers of which the GaN-based semiconductor layer 110 is formed, and the GaN-based semiconductor layer 110 the surface of which is exposed is the n-type clad layer 111. In addition, like in the method of fabricating the vertical type GaN-based LED, the p-electrode 202 and the n-electrode 201 need not be formed sequentially, but either the p-electrode 202 or the n-electrode 201 can be formed first.

[57] The invention has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated by those sMlled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the accompanying claims. Industrial Applicability

[58] The present invention relates to a GaN-based LED and a method of fabricating the same, and more particularly, to a GaN-based LED capable of minimizing the structural defect of the GaN-based LED when a substrate is separated from the GaN-based LED and of maximizing light extraction efficiency and a method of fabricating the same.

Claims

[1] A method of fabricating a GaN-based light emitting diode (LED), comprising: forming a plurality of scattering inducing patterns separated from each other at uniform intervals on a substrate; growing a GaN-based semiconductor layer formed of a plurality of layers on an entire surface of the substrate including the scattering inducing patterns; removing the scattering inducing patterns to form scattering inducing grooves in the GaN-based semiconductor layer; and separating the substrate from the GaN-based semiconductor layer by a laser lift off (LLO) method in a state where the scattering inducing patterns are removed.

[2] The method as set forth in claim 1, wherein forming the plurality of scattering inducing patterns comprises: laminating a scattering inducing layer on the substrate; and patterning the scattering inducing layer at uniform intervals to form the plurality of scattering inducing patterns.

[3] The method as set forth in claim 2, wherein the scattering inducing layer is formed of a dielectric material or a metal.

[4] The method as set forth in claim 1, wherein the substrate is formed of one of a silicon (Si) substrate, a GaAs substrate, an MgO substrate, a sapphire (Al O ) substrate, and an SiC substrate or a template substrate obtained by laminating one of GaN, InGaN, AlGaN, and AlInGaN on one of the above substrates.

[5] The method as set forth in claim 1, wherein the height and the width of the scattering inducing patterns and the distance between the scattering inducing patterns are smaller than the wavelength of the light generated from the GaN- based semiconductor layer, respectively.

[6] The method as set forth in claim 1, wherein the height and the width of the scattering inducing patterns and the distance between the scattering inducing patterns are from about 0.1 /M to about 5 /M, respectively.

[7] The method as set forth in claim 1, wherein growing the GaN-based semiconductor layer comprises sequentially forming a buffer layer, an n-type contact layer, an n-type clad layer, a light emitting layer, a p-type clad layer, and a p- type contact layer on the entire surface of the substrate including the scattering inducing patterns.

[8] The method as set forth in claim 7, further comprising forming a reflection plate on an entire surface of the GaN -based semiconductor layer, removing a partial region of the GaN-based semiconductor layer, and forming an n-electrode on an exposed surface of the GaN-based semiconductor layer after separating the substrate from the GaN-based semiconductor layer, wherein a part from which the partial region is removed comprises the p-type clad layer and the light emitting layer, and wherein the GaN-based semiconductor the surface of which is exposed is the n- type clad layer.

[9] The method as set forth in claim 7, further comprising forming a reflection plate and a p-electrode on an entire surface of the GaN-based semiconductor layer, removing the partial region of the GaN-based semiconductor layer, and forming an n-electrode on the exposed surface of the GaN-based semiconductor layer after separating the substrate from the GaN-based semiconductor layer, wherein the part from which the partial region is removed comprises the p-type clad layer and the light emitting layer, and wherein the GaN-based semiconductor the surface of which is exposed is the n- type clad layer.

[10] The method as set forth in claim 1, wherein forming the scattering inducing grooves comprises removing the scattering inducing patterns by performing wet etching.

[11] The method as set forth in claim 1, further comprising mounting a separation supplementary plate on an upper surface of the GaN-based semiconductor layer between growing the GaN-based semiconductor layer formed of the plurality of layers and forming the scattering inducing grooves.

[12] The method as set forth in claim 11, further comprising forming a p-electrode on an upper surface of the GaN-based semiconductor layer before mounting the separation supplementary plate.

[13] The method as set forth in claim 1, further comprising forming one of a transparent electrode and a reflection electrode on an entire surface of the GaN- based semiconductor layer and forming an n-electrode on an entire surface of a lower surface of the GaN-based semiconductor layer including the scattering inducing grooves after separating the substrate from the GaN-based semiconductor layer.

[14] The method as set forth in claim 1, further comprising forming one of a transparent electrode and a reflection electrode and a p-electrode on an entire surface of the GaN-based semiconductor layer and forming an n-electrode on an entire surface of the lower surface of the GaN-based semiconductor layer including the scattering inducing grooves after separating the substrate from the GaN-based semiconductor layer.

[15] A method of fabricating a GaN-based LED, comprising: forming a plurality of scattering inducing patterns separated from each other at uniform intervals on a substrate; growing a GaN-based semiconductor layer formed of a plurality of layers on an entire surface of the substrate including the scattering inducing patterns; separating the substrate from the GaN-based semiconductor layer by a laser lift off (LLO) method; and removing the scattering inducing patterns to form scattering inducing grooves in the GaN-based semiconductor layer.

[16] The method as set forth in claim 15, wherein forming the plurality of scattering inducing patterns comprises: laminating a scattering inducing layer on the substrate; and patterning the scattering inducing layer at uniform intervals to form the plurality of scattering inducing patterns.

[17] The method as set forth in claim 16, wherein the scattering inducing layer is formed of a dielectric material or a metal.

[18] The method as set forth in claim 15, wherein the substrate is formed of one of a silicon (Si) substrate, a GaAs substrate, an MgO substrate, a sapphire (Al O ) substrate, and an SiC substrate or a template substrate obtained by laminating one of GaN, InGaN, AlGaN, and AlInGaN on one of the above substrates.

[19] The method as set forth in claim 15, wherein the height and the width of the scattering inducing patterns and the distance between the scattering inducing patt erns are smaller than the wavelength of the light generated from the GaN-based semiconductor layer, respectively.

[20] The method as set forth in claim 15, wherein the height and the width of the scattering inducing patterns and the distance between the scattering inducing patterns are from about 0.1 μm to about 5 μm, respectively.

[21] The method as set forth in claim 15, wherein growing the GaN-based semiconductor layer formed of the plurality of layers comprises sequentially forming a buffer layer, an n-type contact layer, an n-type clad layer, a light emitting layer, a p-type clad layer, and a p-type contact layer on the entire surface of the substrate including the scattering inducing patterns.

[22] The method as set forth in claim 21, further comprising forming a reflection plate on an entire surface of the GaN-based semiconductor layer, removing a partial region of the GaN-based semiconductor layer, and forming an n-electrode on an exposed surface of the GaN-based semiconductor layer after separating the substrate from the GaN-based semiconductor layer, wherein a part from which the partial region is removed comprises the p-type clad layer and the light emitting layer, and wherein the GaN-based semiconductor the surface of which is exposed is the n- type clad layer.

[23] The method as set forth in claim 21, further comprising forming a reflection plate and a p-electrode on an entire surface of the GaN-based semiconductor layer, removing the partial region of the GaN-based semiconductor layer, and forming an n-electrode on the exposed surface of the GaN-based semiconductor layer after forming the scattering inducing grooves, wherein the part from which the partial region is removed comprises the p-type clad layer and the light emitting layer, and wherein the GaN-based semiconductor the surface of which is exposed is the n- type clad layer.

[24] The method as set forth in claim 15, wherein forming the scattering inducing grooves comprises removing the scattering inducing patterns by performing wet etching.

[25] The method as set forth in claim 15, further comprising forming a p-electrode on an upper surface of the GaN-based semiconductor layer between growing the GaN-based semiconductor layer formed of the plurality of layers and separating the substrate from the GaN-based semiconductor layer.

[26] The method as set forth in claim 15, further comprising forming one of a transparent electrode and a reflection electrode on an entire surface of the GaN- based semiconductor layer and forming an n-electrode on an entire surface of a lower surface of the GaN-based semiconductor layer including the scattering inducing grooves after separating the substrate from the GaN-based semiconductor layer.

[27] The method as set forth in claim 15, further comprising forming one of a transparent electrode and a reflection electrode and a p-electrode on an entire surface of the GaN-based semiconductor layer and forming an n-electrode on an entire surface of the lower surface of the GaN-based semiconductor layer including the scattering inducing grooves after forming the scattering inducing grooves.

[28] A GaN-based LED comprising a GaN-based semiconductor layer formed of a plurality of layers, wherein a scattering inducing unit for scattering light generated from the GaN- based semiconductor layer is provided at a lower end of the GaN-based semiconductor layer, wherein the scattering inducing unit comprises a plurality of scattering inducing grooves formed to be separated from each other at uniform intervals on a lower surface of the GaN-based semiconductor layer, and wherein the GaN-based semiconductor layer is provided on a substrate.

[29] The GaN-based LED as set forth in claim 28, wherein the height and the width of the scattering inducing grooves and the distance between the scattering inducing grooves correspond to the wavelength of the light generated from the GaN-based semiconductor layer, respectively.

[30] The GaN-based LED as set forth in claim 28, wherein the height and the width of the scattering inducing grooves and the distance between the scattering inducing grooves are from about 0.1 μm to about 5 μm, respectively.

[31] The GaN-based LED as set forth in claim 28, wherein the GaN-based semiconductor layer has a structure in which a buffer layer, an n-type contact layer, an n-type clad layer, a light emitting layer, a p-type clad layer, and a p-type contact layer are sequentially laminated.

[32] The GaN-based LED as set forth in claim 31 , wherein a reflection plate and a p-electrode are further provided on an entire surface of the GaN-based semiconductor layer, wherein an n-electrode is further provided on a surface of the GaN-based semiconductor layer exposed by removing a partial region of the GaN-based semiconductor layer, wherein the part from which the partial region is removed comprises the p-type clad layer and the light emitting layer, and wherein the GaN-based semiconductor layer the surface of which is exposed is the n-type clad layer.

[33] The GaN-based LED as set forth in claim 28, wherein one of a transparent electrode and a reflection electrode and a p- electrode are further provided on the entire surface of the GaN -based semiconductor layer, and wherein the n-electrode is further provided on an entire surface of a lower surface of the substrate.

[34] The GaN-based LED as set forth in claim 28, wherein the substrate is formed of one of a silicon (Si) substrate, a GaAs substrate, an MgO substrate, and a sapphire (Al O ) substrate or a template substrate obtained by laminating one of GaN, InGaN, AlGaN, and AlInGaN on one of the above substrates.