KR20140059522A - Light emitting device comprising gallium-nitride substrate and light emitting diode package comprising the same - Google Patents

Abstract

Disclosed is a light emitting device including a gallium nitride substrate and a light emitting diode package including the same. The light emitting device includes a gallium nitride substrate having a lower surface and an upper surface; A light emitting structure including a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer, the first conductivity type semiconductor layer being located on a top surface side of the gallium nitride substrate; And a metal layer positioned on a lower surface side of the gallium nitride substrate, wherein the gallium nitride substrate includes a roughness formed on a lower surface thereof, and the metal layer has a lower surface that is flatter than the lower surface of the gallium nitride substrate. Meanwhile, the light emitting diode package includes the light emitting device and the base substrate, and the light emitting device and the base substrate are process bonded. Such a light emitting device and a light emitting diode package provide an improvement in reliability and an improvement in luminous efficiency and heat emission efficiency.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a light emitting device including a gallium nitride substrate and a light emitting diode package including the gallium nitride substrate. 2. Description of the Related Art [0002] LIGHT EMITTING DEVICE COMPRISING GALLIUM NITRIDE SUBSTRATE AND LIGHT EMITTING DIODE PACKAGE COMPRISING THE SAME,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device including a gallium nitride substrate and a light emitting diode package including the same, and more particularly, to a light emitting device having improved heat dissipation efficiency and a light emitting diode package including the same.

The light emitting device is a semiconductor optical device using the principle that when energy is applied to a junction between a P-type semiconductor and an N-type semiconductor, the energy released when the electrons in the N-region and the holes in the P- Particularly, a light emitting device using a III-V semiconductor such as gallium nitride (GaN) has a direct transition type energy band structure and has a high internal quantum efficiency. Therefore, gallium nitride is recently regarded as a material of a light emitting device have.

As the gallium nitride semiconductor layer growth substrate, a heterogeneous substrate such as a sapphire substrate, a SiC substrate, or a ZnO substrate is mainly used. In particular, a sapphire substrate has a hexagonal system similar to gallium nitride, is relatively inexpensive, and has high thermal stability, and is thus mainly used as a substrate for growing a gallium nitride semiconductor layer.

However, the difference in lattice constant and the thermal expansion coefficient between the sapphire substrate and the gallium nitride semiconductor layer are very large, and internal defects such as dislocation are generated at a high density in the gallium nitride semiconductor layer grown on the sapphire substrate . Due to defects in the gallium nitride semiconductor layer, the luminous efficiency of the light emitting device is lowered and the reliability is lowered. In addition, there is a demand for a light emitting device that operates at a high current density, with the demand for a high output light emitting device and a light emitting diode package increasing in recent years. However, a light emitting device manufactured by growing a heterogeneous substrate has a problem of increasing a leakage current at a high current density due to internal defects, and there is a limitation in increasing the current density.

In order to solve the above problems of the light emitting device grown on the different substrate, a technique for manufacturing a light emitting device by growing a gallium nitride semiconductor layer on the same type substrate has been developed. The light emitting device using the same substrate as the growth substrate has a very low defect density, and is excellent in efficiency and reliability.

1 shows a conventional light emitting diode package mounted with a light emitting device using a same substrate as a growth substrate. The light emitting diode package includes a light emitting device 110 for bonding a light emitting device 110, a base substrate 100 and a light emitting device 110 including a gallium nitride based light emitting structure 111 and a gallium nitride substrate 113 to a base substrate 100 And a bonding material 120. Here, the gallium nitride substrate 113 has a rough lower surface 113a, which is caused by the manufacturing process of the gallium nitride substrate 113. [ Since the lower surface 113a of the gallium nitride substrate 113 is very rough, the silver (Ag (Ag)) that can fill the concave portion of the rough lower surface 113a has been conventionally used in order to mount the light emitting element 110 on the base substrate 100 ) Paste or a silicon paste was used as the bonding material 120. [

However, in the case of a light emitting diode package using a silver paste as the bonding material 120, the light intensity of the package is lowered due to the absorption of light by the paste, and in the case of the light emitting diode package using the silicon paste as the bonding material 120, And the product characteristics are deteriorated. Therefore, it is difficult to obtain a good luminous efficiency or heat emission efficiency as a conventional bonding material when a high output light emitting diode package is manufactured.

On the other hand, it is possible to consider using process bonding (Eutectic bonding) in order to increase the heat emission efficiency of the light emitting device. However, the gallium nitride substrate 113 having the rough lower surface 113a is difficult to be bonded to the base substrate 100 using process bonding. In addition, since the rough lower surface 113a of the conventional gallium nitride substrate 113 is not roughly formed as a whole but includes a flat portion in some places, the total internal reflection is generated, and thus the luminous intensity of the light emitting device is lowered have.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light emitting device including a gallium nitride substrate capable of preventing a decrease in luminous intensity and improving heat emission efficiency, and a method of manufacturing the same.

Another object of the present invention is to provide a light emitting diode package and a method of manufacturing the same that can improve heat emission efficiency generated in a light emitting device including a gallium nitride substrate.

Another object of the present invention is to provide a light emitting device and a light emitting diode package having improved heat dissipation efficiency by providing a method of easily forming a metal layer on the lower surface side of a gallium nitride substrate.

A light emitting device according to an embodiment of the present invention includes a gallium nitride substrate having a lower surface and a top surface, a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer disposed on the upper surface side of the gallium nitride substrate And a metal layer located on a lower surface side of the gallium nitride substrate, wherein the gallium nitride substrate includes a roughness formed on a lower surface thereof, and the metal layer has a lower surface which is flatter than the lower surface of the gallium nitride substrate.

The light emitting device includes a metal layer having a flat bottom surface, thereby improving heat dissipation efficiency of the light emitting device and facilitating mounting during package manufacture.

At this time, the metal layer may include Au.

The metal layer may fill the recess of the roughness. As described above, the metal layer can fill the recess of the roughness, and the lower surface of the metal layer can be made even more flat.

In addition, the roughness may include main roughness and sub-roughness, and the sub roughness may be formed along the surface of the main roughness. At this time, the scale of the sub-roughness may be smaller than that of the mail roughness.

Further, the maximum height of the convex portion of the main roughness may be in the range of 0.5 to 3.5 mu m, thereby facilitating the formation of the metal layer covering the roughness.

The light emitting device may further include a reflective layer positioned between the gallium nitride substrate and the metal layer to increase light directed toward the side surface and the upper surface of the light emitting device.

At this time, the reflective layer may include at least one of DBR (Distributed Bragg Reflector) and Ag.

A light emitting diode package according to another embodiment of the present invention includes a base substrate, a light emitting element located on the base substrate, a bonding layer positioned between the base substrate and the light emitting element, Is one of the light emitting elements of the present invention.

The bonding layer may include an eutectic structure. Further, the bonding layer may include Au and Sn, and Au and Sn may form a process structure.

The light emitting diode package in which the light emitting device is processed and bonded to the base substrate can provide an excellent heat emission effect.

According to another embodiment of the present invention, there is provided a method of manufacturing a light emitting device, comprising: preparing a gallium nitride substrate having an upper surface and a lower surface and including roughness on the lower surface; Forming a light emitting structure including a conductive semiconductor layer, an active layer and a second conductive semiconductor layer, and forming a metal layer covering the lower surface of the gallium nitride substrate. At this time, the metal layer may include a lower surface that is flatter than the lower surface of the gallium nitride substrate.

The method further includes forming a roughness by surface-treating the lower surface of the gallium nitride substrate so as to have a surface roughness smaller than that of the lower surface of the gallium nitride substrate before forming the metal layer .

Accordingly, it is easy to form the metal layer on the lower surface side of the gallium nitride substrate in manufacturing the light emitting device of the present invention.

Further, the metal layer may include a lower surface which is flatter than the lower surface of the gallium nitride substrate after the surface treatment.

Forming the roughness by lapping the lower surface of the gallium nitride substrate and forming a main roughness on the lower surface of the gallium nitride substrate; And wet-etching the surface to form a sub-roughness formed along the main roughness surface.

Thus, the surface of the lower surface of the gallium nitride substrate can be surface-treated to easily form a metal layer without lowering the light intensity, thereby improving the heat emission efficiency of the light emitting device.

In forming the roughness, the maximum height of the convex portion of the main roughness may be in the range of 0.5 to 3.5 mu m.

The method of manufacturing a light emitting device may further include forming a reflective layer covering the lower surface of the gallium nitride substrate before forming the metal layer.

The method of manufacturing a light emitting device may further include forming a seed layer on the lower surface side of the gallium nitride substrate before forming the metal layer, and further the seed layer may be formed by electron beam evaporation.

The metal layer may be formed from the seed layer, and the metal layer may be formed by plating.

A method of manufacturing a light emitting diode package according to another embodiment of the present invention includes forming a light emitting device and bonding the light emitting device to a base substrate, It is formed by any one manufacturing method.

In the method of manufacturing the light emitting diode package, the light emitting device may be subjected to eutectic bonding on the base substrate.

The process bonding may include forming AuSn on the base substrate, heating the AuSn to an eutectic temperature or more, and cooling the AuSn to a temperature lower than the process temperature.

According to the present invention, by including the gallium nitride substrate and the metal layer having the roughness, the luminous efficiency and the heat emission efficiency of the light emitting device can be improved. In addition, since the light emitting device can be process-bonded onto the base substrate, heat emission efficiency can be greatly improved while maintaining the light intensity of the light emitting diode package.

Further, it is possible to provide a method of easily forming a metal layer on the lower surface side of a gallium nitride substrate, thereby providing a method of manufacturing a light emitting device having no reduction in brightness and improved heat emission efficiency. In addition, by providing a method of bonding a light emitting device to a base substrate through process bonding, a method of manufacturing a light emitting diode package with improved heat emission efficiency can be provided.

1 is a cross-sectional view illustrating a conventional light emitting diode package.
2 is a cross-sectional view illustrating a light emitting device according to an embodiment of the present invention.
FIGS. 3 to 7 are cross-sectional views illustrating a method of manufacturing a light emitting device according to an exemplary embodiment of the present invention. Particularly, FIGS. 3B and 5B are SEM (Scanning Electron Microscope) Pictures.
8 is a cross-sectional view illustrating a light emitting diode package and a method of manufacturing the same according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so that those skilled in the art can sufficiently convey the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. It is also to be understood that when an element is referred to as being "above" or "above" another element, But also includes the case where there are other components in between. Like reference numerals designate like elements throughout the specification.

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

2, the light emitting device includes a gallium nitride substrate 10, a metal layer 43, a first conductive semiconductor layer 21, an active layer 23, and a second conductive semiconductor layer 25, (20). The light emitting device may further include a reflective layer 41 disposed between the gallium nitride substrate 10 and the metal layer 43. The first conductive semiconductor layer 21 and the second conductive semiconductor layer 25 The first electrode 33 and the second electrode 31 may be disposed on the first electrode 33 and the second electrode 31, respectively.

The gallium nitride substrate 10 may be a polar gallium nitride substrate such as a c-plane gallium nitride substrate, or may be a nonpolar gallium nitride substrate such as an m-plane or an a-plane gallium nitride substrate. Further, the gallium nitride substrate 10 may be a semi-polarized gallium nitride substrate. In addition, the gallium nitride substrate 10 may have an inclination angle to assist growth of epitaxial layers to be grown. The gallium nitride substrate 10 may be manufactured using, for example, a hydride vapor phase epitaxy (HVPE) process.

The gallium nitride substrate 10 has an upper surface and a lower surface. At this time, the gallium nitride substrate 10 may include a roughness 11 formed on a lower surface thereof. The roughness 11 can prevent the light emitted from the active layer 23 from being totally reflected in the light emitting device and disappearing.

The roughness 11 may include irregular concavities and convexities, and may include the main roughness 11a and the sub roughness 11b.

Referring to FIG. 2, the roughness 11 is shown as having a main roughness 11a and a sub roughness 11b. As shown, the sub roughness 11b has a relatively small size as compared with the main roughness 11a. The main roughness 11a means a roughness of a relatively large scale and includes relatively large irregularities, and the sub roughness 11b means a roughness of a relatively small scale and includes relatively small irregularities. Here, the sub roughness 11b may be formed along the surface of the main roughness 11a. At this time, it is preferable that the lower surface of the gallium nitride substrate 10 has no flat surface.

The conventional gallium nitride substrate has a flat surface on the lower surface and thus has a disadvantage in that the luminous intensity of the light emitting device is lowered. However, according to the present invention, since the roughness 11 includes the main roughness 11a and the sub roughness 11b formed along the surface of the main roughness 11a, the lower surface of the gallium nitride substrate 10 The area of the flat surface can be minimized. Thus, the luminous intensity of the light emitting element can be improved.

On the other hand, the maximum height of the convex portion of the main roughness 11a may be in the range of 0.5 to 3.5 mu m. The metal layer 43 can easily cover the roughness 11 by forming the maximum height of the convex portion of the main roughness 11a within such a range. In other words, even if the metal layer 43 has a relatively thin thickness compared to the conventional one, the roughness 11 can be completely covered and the lower surface of the metal layer 43 can be formed flat.

On the other hand, the convex portion of the sub roughness 11b may be formed with a maximum height within the range of 100 to 400 nm.

As described above, the metal layer 43 may be located on the lower surface side of the gallium nitride substrate 10, and may be formed to cover the roughness 11. The lower surface of the metal layer 43 may be formed to be flatter than the lower surface of the gallium nitride substrate 10 and the roughness degree of the metal nitride layer 43 may preferably be lower than the roughness of the gallium nitride substrate 10 by the main roughness 11a Respectively.

The material of the metal layer 43 is not limited as long as it is a metal, and may be, for example, a metal including Au.

As described above, the light emitting device of the present invention includes the metal layer 43 so that the heat emission efficiency of the light emitting device can be improved. In addition, since the lower surface of the metal layer 43 is formed flat, it can be bonded to the base substrate using eutectic bonding in the light emitting device packaging process. Accordingly, the efficiency of heat emission of the light emitting device is improved, and the reliability of the light emitting device can be greatly improved.

The reflective layer 41 may be located between the gallium nitride substrate 10 and the metal layer 43. The reflective layer 41 serves as a reflector for emitting downward light emitted from the active layer 23 and may include a metal reflective material such as DBR (Distributed Bragg Reflector) or Ag. Particularly, the DBR (Distributed Bragg Reflector) can be selectively applied according to the peak wavelength of the light emitted from the active layer, and the material to be laminated to form the DBR (Distributed Bragg Reflector) is not limited.

On the other hand, the light emitting structure 20 is located on the upper surface side of the gallium nitride substrate 10. The light emitting structure 20 includes a first conductive semiconductor layer 21, an active layer 23, and a second conductive semiconductor layer 25 sequentially formed.

The light emitting device may further include an intermediate buffer layer (not shown) positioned between the gallium nitride substrate 10 and the light emitting structure 20. The intermediate buffer layer may serve to lower the internal defect density of the semiconductor layers 21, 23, and 25 grown on the gallium nitride substrate 10. The reason for this is as follows. Even when the gallium nitride epitaxial layer is formed using the same type of substrate, the grown epitaxial layer has a tendency to grow in the c-plane when the gallium nitride substrate 10 is a non-polar or semi-polar substrate. Therefore, when forming a gallium nitride semiconductor layer of a non-polar or semi-polar nature, it may be preferable to further form an intermediate buffer layer for growth of a high-quality gallium nitride semiconductor layer.

Here, the first conductivity type semiconductor layer 21 and the second conductivity type semiconductor layer 25 are different conductivity type semiconductor layers. For example, in the present embodiment, the first conductivity type semiconductor layer 21 may be an n-type semiconductor layer and the second conductivity type semiconductor layer 25 may be a p-type semiconductor layer or vice versa. The first conductive semiconductor layer 21 and the second conductive semiconductor layer 25 may be formed of a nitride based semiconductor layer. For example, the nitride based semiconductor layer may include (Al, Ga, In) N can do. The first conductivity type semiconductor layer 21 and the second conductivity type semiconductor layer 25 may be a single layer or a multilayer. For example, the first conductive semiconductor layer 21 and / or the second conductive semiconductor layer may include a contact layer and a clad layer, or may include a superlattice layer, .

The active layer 23 may include a single quantum well structure including a light emitting layer and a barrier layer, or may include a multiple quantum well structure including a plurality of light emitting layers and a barrier layer. The active layer 23 may include a nitride-based semiconductor layer whose composition and composition are controlled so as to emit light having a desired peak wavelength.

Although not shown, the electron blocking layer EBL may be further formed between the active layer 23 and the second conductivity type semiconductor layer 25 to increase the internal quantum efficiency of the light emitting device.

The semiconductor layers 21, 23 and 25 of the light emitting structure 20 may be formed using MOCVD (Metal Organic Chemical Vapor Deposition), MBE (Molecular Beam Epitaxy), or HVPE (Hydride Vapor Phase Epitaxy) A part of the first conductive semiconductor layer 21 is exposed using a photolithography process and an etching process. As shown in FIG. 2, the light emitting device of this embodiment is patterned so that the active layer 23 and the second conductivity type semiconductor layer 25 have a mesa structure. Although the mesa is shown as having a side surface perpendicular to the top surface of the first conductivity type semiconductor layer 21, the mesa may include an inclined side surface.

The first electrode 33 and the second electrode 31 are disposed on the first conductivity type semiconductor layer 21 and the second conductivity type semiconductor layer 25, respectively, and are in ohmic contact with each other. At this time, a transparent electrode (not shown) may be further disposed under the second electrode 31 and on the second conductive type semiconductor layer 25, and the transparent electrode may further facilitate current dispersion, The strength can be increased.

According to this embodiment, the light emitting device includes the roughness 11 formed on the lower surface of the gallium nitride substrate 10 and the metal layer 43 covering the roughness 11, so that the intensity of light emitted to the outside of the light emitting device is not reduced The emission efficiency can be increased. Further, by forming the lower surface of the metal layer 43 to be more flat than the lower surface of the gallium nitride substrate 10, it is possible to provide an effect of greatly improving the heat emission efficiency of the light emitting diode package including the light emitting element have.

FIGS. 3 to 7 are cross-sectional views illustrating a method of manufacturing a light emitting device according to an exemplary embodiment of the present invention. Particularly, FIGS. 3B and 5B are SEM (Scanning Electron Microscope) Pictures.

First, referring to FIG. 3A, a gallium nitride substrate 10 'having an upper surface and a lower surface is prepared. The gallium nitride substrate 10 'may be manufactured using, for example, HVPE technology.

The gallium nitride substrate 10 'may be a non-polar substrate such as an m-plane or an a-plane, a polar substrate such as a c-plane, or a semipolar substrate. The gallium nitride substrate 10 'includes a top surface and a rough bottom surface 11' on which the gallium nitride epitaxial layer is grown. The gallium nitride substrate 10 'may be provided by separating a heterogeneous substrate from a gallium nitride epitaxial layer grown on a heterogeneous substrate. In this case, the rough lower surface 11 'of the gallium nitride substrate 10' is caused by the manufacturing process of the gallium nitride substrate 10 ', and is formed of a rough The lower surface 11 'is formed.

3B is a SEM photograph showing the surface of the lower surface of the gallium nitride substrate 10 'according to one embodiment. As shown in the photograph, the gallium nitride substrate 10 'has a rough lower surface 11' including irregular concave and convex portions, and the maximum height of convex portions of the rough lower surface 11 'is approximately 1-15 μm . Since the roughness 11 'of such a scale is formed on the lower surface of the gallium nitride substrate 10', conventionally, the light emitting device is bonded to the package substrate using silver paste or silicon paste. Therefore, the conventional light emitting diode package has a problem that the heat emission efficiency is lowered or the light intensity is lowered. Thus, the inventors of the present invention have solved the above-mentioned problems through the following manufacturing method.

The first conductivity type semiconductor layer 21, the active layer 23 and the second conductivity type semiconductor layer 25 are successively grown on the upper surface of the gallium nitride substrate 10 'after the gallium nitride substrate 10' Thereby forming a light emitting structure 20. [ These semiconductor layers 21, 23, and 25 may be grown using techniques such as MOCVD, MBE, or HVPE. Although not shown, an intermediate buffer layer is formed on the gallium nitride substrate 10 'to improve the crystallinity and morphology of the semiconductor layers 21, 23 and 25 to be grown, and then the semiconductor layers 21, 23, 25) can be grown. At this time, the intermediate buffer layer may be formed to a thickness of about 2-10 nm at about 700-800 ° C.

Next, as shown in FIGS. 4 and 5A, the lower surface of the gallium nitride substrate 10 'is surface-treated to form a gallium nitride substrate 10 including the roughness 11.

Referring first to FIG. 4, the rough bottom surface 11 'of the gallium nitride substrate 10' is processed to reduce the height of the convex portion of the rough bottom surface 11 '. At this time, machining the rough bottom surface 11 'may be, for example, lapping using a diamond slurry. As described above, the roughness 11 including the main roughness 11a is formed on the lower surface of the gallium nitride substrate 10 after the lapping process. The main roughness 11a may be formed such that its maximum height is lower than the height of the roughness 11 'before machining, and preferably it is formed within a range of 0.5 to 3.5 占 퐉. However, the present invention is not limited to this, and the height of the main roughness 11a may be lower or higher.

As described above, the roughness 11 of the surface-treated gallium nitride substrate 10 has a relatively small surface roughness as compared with the rough lower surface 11 'of the gallium nitride substrate 10' before processing.

Next, referring to FIG. 5A, after the main roughness 11a is formed, the lower surface of the gallium nitride substrate 10 is etched to form the sub roughness 11b. At this time, it is preferable to use wet etching. For example, etching can be performed at about 190 ° C for 20 minutes using a sulfuric acid phosphoric acid solution in which phosphoric acid and sulfuric acid are mixed at a ratio of 1: 3. At this time, the higher the sulfuric acid ratio is, the larger the etching degree may be, but the present invention is not limited thereto, and the etching temperature, time, and solution mixing ratio can be freely selected.

The sub-roughness 11b formed using the wet etching process is generally formed along the crystal face of the gallium nitride substrate 10, but may not be formed regularly and regularly. The maximum height of the convex portion of the sub roughness 11b may be about 100-400 nm and may be formed along the surface of the lower surface of the gallium nitride substrate 10, that is, the surface of the main roughness 11a.

5B is a SEM photograph showing the surface of the lower surface of the gallium nitride substrate 10 according to one embodiment. As shown in the figure, the lower surface of the gallium nitride substrate 10 has a roughness 11, and the roughness 11 includes a main roughness 11a and a sub-surface 11a formed along the surface of the main roughness 11a. And a roughness lib. Further, as shown in the photograph, the lower surface of the gallium nitride substrate 10 has the roughness 11 as a whole without a flat surface.

As described above, by forming the sub roughness 11b having a relatively small scale relative to the main roughness 11a on the lower surface of the gallium nitride substrate 10, the entire roughness of the roughness lower surface 11 ' The roughness 11 including the dense irregularities can be provided on the lower surface of the gallium nitride substrate 10. [ As a result, the light intensity of the light emitting element can be prevented from being lowered due to the flat surface of the lower surface of the gallium nitride substrate 10, and the light intensity of the light emitting element can be improved. Further, the maximum height of the convex portion of the main roughness 11a is about 0.5-3.5 mu m, and the scale of the roughness 11 can be significantly smaller than the roughness 11 'before the surface treatment. Accordingly, the process of forming the metal layer 41 to be described later can be facilitated.

Next, as shown in FIG. 6, a reflective layer 41 and a seed layer 43 'are formed in order on the lower surface side of the surface-treated gallium nitride substrate 10.

The reflective layer 41 may be formed to reflect the downward light out of the light emitted from the active layer 23 to increase the brightness of the light emitting device. The reflective layer 41 is not limited as long as it is a reflective material, and may include a metal such as DBR (Distributed Bragg Reflector) or Ag. At this time, the DBR (Distributed Bragg Reflector) can be selected according to the light emitted from the active layer, and two or more kinds of materials can be laminated by a process such as vapor deposition. In addition, metals such as Ag can be formed using techniques such as E-beam evaporation. Meanwhile, the reflective layer 41 may be omitted if necessary.

Subsequently, a seed layer 43 'is formed under the reflective layer 41. The seed layer 43 'may serve as a seed or nucleus for forming the metal layer 43 and may therefore be formed of a material which is preferably the same as the material forming the metal layer 43. For example, the seed layer 43 'may be formed of a metal containing Au. The seed layer 43 'may be formed using an electron beam deposition technique. In the figure, the seed layer 43 'is exaggerated for clarity.

Referring next to FIG. 7, a metal layer 43 located below the reflective layer 41 is formed.

The metal layer 43 may be formed by a method such as electron beam evaporation or plating. Preferably, the metal layer 43 may be formed by a plating method using the seed layer 43 'as a seed material. Accordingly, the metal layer 43 may be formed of the same material as the material forming the seed layer 43 ', and may be formed of a metal material including, for example, Au. Since the light emitting device of the present invention includes the metal layer 43 formed on the lower surface side of the gallium nitride substrate 10, the heat emission efficiency can be improved.

In this case, the metal layer 43 may be formed to cover the roughness 11, and the lower surface of the metal layer 43 may be formed to be flatter than the lower surface of the gallium nitride substrate 10. Therefore, it is preferable that the metal layer 43 is formed to be thicker than the maximum height of the convex portion of the main roughness 11a.

When the metal layer 43 is formed to be thicker than the maximum height of the convex portion of the main roughness 11a, when the flat metal layer 43 is formed, eutectic bonding is performed when packaging the light emitting device to the base substrate, Can be used. When the two elements are bonded through the process bonding, there is an advantage in that the thermal conductivity is excellent. Therefore, the light emitting diode package using the light emitting device of this embodiment provides a significant improvement in the heat radiation efficiency.

In addition, when the metal layer 43 is formed by the plating method, the flat metal layer 43 can be formed easily as compared with the conventional case. Since the conventional gallium nitride substrate 10 'includes a roughness 11' having a scale of 1-15 μm on the lower surface thereof, it is necessary to form a metal layer having a maximum thickness of 15 μm or more in order to flatten the lower surface by plating the metal do. On the other hand, in the case of the present invention, the roughness 11 on the lower surface of the gallium nitride substrate 10 has a maximum scale of 0.5-3.5 m, so that only the metal layer 43 having the maximum thickness of 3.5 m or more is formed, The metal layer 43 having a flat bottom can be formed while covering the metal layer 11. Therefore, according to the method for manufacturing a light emitting device of the present invention, the plating process for forming the metal layer 43 is easy, and the process cost can be saved.

Thereafter, a part of the second conductivity type semiconductor layer 25 and the active layer 23 is etched to form a mesa such that a part of the first conductivity type semiconductor layer 21 is exposed. When the second electrode 31 is formed on the second conductivity type semiconductor layer 25 and the first electrode 33 is formed in a region where a part of the first conductivity type semiconductor layer 21 is exposed, Is provided.

In the present embodiment, the lower surface of the gallium nitride substrate 10 is surface-treated after the first electrode 33 and the second electrode 31 are formed. However, the present invention is not limited to this, The lower surface of the gallium nitride substrate 10 may be surface-treated. In the order of the method of manufacturing a light-emitting device, ordinary technicians can freely modify the scope of the present invention without departing from the technical idea of the present invention.

8 is a cross-sectional view illustrating a light emitting diode package and a method of manufacturing the same according to an embodiment of the present invention.

Referring to FIG. 8, the light emitting diode package includes a base substrate 200, a light emitting device 1000, a bonding layer 220, a first lead electrode 210, a second lead electrode 230, a first wire 215 A second wire 235, and an encapsulating material 250. [

The base substrate 200 is not limited as long as it is a substrate to which the light emitting device 1000 can be bonded, and may be a conductive or insulating substrate. For example, the base substrate 200 may be a PCB substrate, a Si substrate, or the like. The base substrate 200 may further include a heat sink (not shown) for more easily discharging the heat emitted from the light emitting device 1000.

Further, the base substrate 200 includes a first lead electrode 210 and a second lead electrode 230. The first and second lead electrodes 210 and 230 are electrically insulated from each other and have mutually opposite polarities.

The light emitting device 1000 may be any one of the light emitting devices according to the embodiments described above, and any light emitting device that does not depart from the spirit of the present invention may be used.

The bonding layer 220 is located between the light emitting device 1000 and the base substrate 200. The bonding layer 220 may function to bond the light emitting device 1000 to the base substrate 200.

The light emitting device 1000 may be bonded to the base substrate 200 through the bonding layer 220. For example, the process bonding is performed by forming AuSn on the base substrate, placing the light emitting device 1000 on the AuSn, heating the AuSn to an eutectic temperature or more, And may be cooled again to a temperature below the process temperature. At this time, the process temperature is about 280 占 폚 and the eutectic composition is Au: Sn = 80: 20 (wt%). Accordingly, the bonding layer 220 may include Au and Sn, and Au and Sn may form a process structure with respect to each other. Therefore, the bonding layer 220 may include an eutectic structure. However, the present invention is not limited thereto, and various heterogeneous materials having an eutectic point may be used for process bonding.

As described above, the light emitting diode package of the present invention forms the bonding layer 220 through process bonding, so that there is no problem that the adhesive rises on the sidewall of the light emitting device 1000 to cause a short circuit of the light emitting device 1000. In addition, the light emitting diode package can provide excellent heat emission efficiency without causing a decrease in luminous intensity.

The first electrode of the light emitting device 1000 and the first lead electrode 210 are electrically connected through the first wire 215 and the second electrode of the light emitting device 1000 is electrically connected to the second lead electrode 230. [ And the second wire (235).

Thereafter, an encapsulating material 250 for encapsulating the light emitting device 1000 and the wires 215 and 235 is formed on the base substrate 200. The encapsulant 250 may be formed using a known material, for example, silicon or epoxy, and the manufacturing method is not limited either. Further, the encapsulant 250 may further include a phosphor.

Since the light emitting diode package as described above is manufactured by using the light emitting element including the roughness 11 and the metal layer 43, the luminous efficiency and the heat emission efficiency can be improved, and since the process bonding is used, Reliability is improved with improvement.

INDUSTRIAL APPLICABILITY As described above, the light emitting device and the light emitting diode package of the present invention can operate at high output and can provide high efficiency and reliability at high output.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Variations and changes are possible.

Claims (22)

A gallium nitride substrate having a bottom surface and a top surface;
A light emitting structure including a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer, the first conductivity type semiconductor layer being located on a top surface side of the gallium nitride substrate; And
And a metal layer located on a lower surface side of the gallium nitride substrate,
Wherein the gallium nitride substrate includes a roughness formed on a lower surface thereof,
Wherein the metal layer has a lower surface that is flatter than the lower surface of the gallium nitride substrate. The method according to claim 1,
Wherein the metal layer fills the recess of the roughness. The method according to claim 1,
Wherein the roughness includes a main roughness and a sub roughness,
And the sub-roughness is formed along a surface of the main roughness. The method of claim 3,
Wherein a maximum height of a convex portion of the main roughness is in a range of 0.5 to 3.5 mu m. The method according to claim 1,
And a reflective layer positioned between the gallium nitride substrate and the metal layer. The method of claim 5,
Wherein the reflective layer comprises at least one of DBR (Distributed Bragg Reflector) and Ag. The method according to claim 1,
Wherein the metal layer comprises Au. A base substrate;
A light emitting element located on the base substrate;
And a bonding layer disposed between the base substrate and the light emitting device,
Wherein the light emitting device is the light emitting device according to any one of claims 1 to 7. The method of claim 8,
Wherein the bonding layer comprises an eutectic structure. The method of claim 9,
Wherein the bonding layer comprises Au and Sn, and the Au and Sn form a process structure. Preparing a gallium nitride substrate having a top surface and a bottom surface and including a roughness on the surface of the bottom surface,
Forming a light emitting structure including a first conductivity type semiconductor layer, an active layer and a second conductivity type semiconductor layer on the upper surface side of the gallium nitride substrate,
And forming a metal layer covering the lower surface of the gallium nitride substrate,
Wherein the metal layer has a lower surface that is flatter than the lower surface of the gallium nitride substrate. The method of claim 11,
Before forming the metal layer,
Further comprising forming a roughness by surface-treating the lower surface of the gallium nitride substrate so that the surface roughness of the lower surface of the gallium nitride substrate is smaller than the roughness of the lower surface of the gallium nitride substrate. The method of claim 12,
Wherein the metal layer comprises a lower surface that is flatter than the lower surface of the gallium nitride substrate after the surface treatment. The method of claim 12,
To form the roughness,
Laminating the lower surface of the gallium nitride substrate,
Forming a main roughness on the lower surface of the gallium nitride substrate,
And wet etching the lower surface of the gallium nitride substrate to form a sub roughness formed along the main roughness surface. 15. The method of claim 14,
Wherein a maximum height of the convex portion of the main roughness is in a range of 0.5 to 3.5 mu m. The method of claim 12,
Before forming the metal layer,
And forming a reflective layer covering the lower surface of the gallium nitride substrate. The method of claim 12,
Before forming the metal layer,
And forming a seed layer on the lower surface side of the gallium nitride substrate. 18. The method of claim 17,
Wherein the seed layer is formed by electron beam evaporation. 19. The method of claim 18,
Wherein the metal layer is formed by plating. Forming a light emitting element,
And bonding the light emitting device to a base substrate,
Wherein the light emitting element is formed by the manufacturing method according to any one of claims 12 to 19. The method of claim 20,
Wherein the light emitting device is subjected to eutectic bonding on the base substrate. 23. The method of claim 21,
The process bonding may include,
AuSn is formed on the base substrate,
The AuSn is heated to an eutectic temperature or higher,
And cooling the AuSn to a temperature below the process temperature.

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