KR100647814B1 - Light emitting diode device having high luminance characteristics - Google Patents

Abstract

The present invention relates to a light emitting diode device, and more particularly, to a light emitting diode device in which the structure of the semiconductor layer and the electrode is modified to improve the light extraction efficiency and the light generation efficiency.

In one aspect, a light emitting diode device includes: a substrate; N-type semiconductor layer; An active layer for generating light; A light emitting diode device comprising: a first exposure surface exposing at least a portion of the N-type semiconductor layer by etching the active layer and the P-type semiconductor layer; A first ohmic electrode formed on the first exposure surface; A mesh shape formed on the P-type semiconductor layer, the opening having a portion of the P-type semiconductor layer having a second exposure surface, wherein at least one rectangular opening is repeatedly arranged in a lattice shape, and at least one Any one of the shapes selected from the mesh shape in which the above-described trapezoidal openings are repeatedly arranged radially or the mesh shape in which zigzag branches extend in the direction of the first ohmic electrode about the opposite corner of the diagonal direction of the first ohmic electrode. A second ohmic electrode having; Random texturing is performed on the second exposed surface, which is the P-type semiconductor layer except for the first exposed surface and the second ohmic electrode forming surface, except the surface on which the first ohmic electrode is to be formed, and the first exposure surface and the P-type semiconductor are formed. Ag, Al, Au, Cr, In, Ir, Ni, Pd, Pb, Pt, Rd, Sn, Ti, W or a combination of these metals are applied to the layer and heat treated at high temperature to form metal clusters. Through the photolithography process, to remove the metal mass in the portion where the first ohmic electrode is formed on the first exposure surface and the portion where the second ohmic electrode is formed in the P-type semiconductor layer, and dry or wet using the remaining metal mass Etching includes the first exposure surface and the second exposure surface other than the formation surface of the first ohmic electrode is rough, and is formed on the second exposure surface and the second ohmic electrode of the P-type semiconductor layer Light directed from the active layer toward the semiconductor layer A flip chip bonding electrode which reflects the light to the surface; A conductive material bonded to the flip chip bonding electrode and conducting current and heat; And a sub-mount bonded to the conductive material and transferring current to the N-type semiconductor and dissipating heat generated in the active layer to the outside.

LED, light emitting, diode, high brightness

Description

LIGHT EMITTING DIODE DEVICE HAVING HIGH LUMINANCE CHARACTERISTICS}

The following drawings attached to this specification are illustrative of preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to

1 is a cross-sectional view of a light emitting diode device having a conventional mesh-shaped ohmic electrode.

2 is a cross-sectional view of a light emitting diode device having a conventional rough surface semiconductor layer.

3 is a schematic perspective view of a light emitting diode device according to an embodiment of the present invention.

4A is a cross-sectional view taken along the direction S1 of FIG. 3.

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

5A, 5B, 5C and 5D are top plan views of a light emitting diode device according to an embodiment of the present invention.

6 is a cutaway view of a light emitting diode device having a flip chip structure according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10 Light Transmissive Substrate A1 First Exposure Surface

20 N-type semiconductor layer A2 second exposure surface

30 active layer 60 light transmitting electrode

Metal pad for 40P type semiconductor layer 70 wire bonding

50 Ohmic Electrode 80 Flip Chip Bonding Electrode

50a first ohmic electrode 90 conductive material

50b second ohmic electrode 100 conductive electrode

                                        110 submount

The present invention relates to a light emitting diode device, and more particularly, to a light emitting diode device in which the structure of the semiconductor layer and the electrode is modified to improve the light extraction efficiency and the light generation efficiency.

Light Emitting Diode (hereinafter, referred to as 'LED') is a type of solid-state device that converts electrical energy into light, and is generally a semiconductor material interposed between two opposite doped semiconductor layers (N-type, P-type). It includes an active layer of. When a bias is applied across the two doped semiconductor layers, holes and electrons are injected into the active layer and then luminescent recombination therein to generate light. Light generated in the active region is emitted in all directions, and some of them escape from the semiconductor chip through the exposed surface.

 Recently, as semiconductor materials are improved, the efficiency of semiconductor devices has also been improved. The new LEDs are made of gallium nitride (GaN) -based materials that allow efficient illumination in the ultraviolet to green spectrum. As LEDs improve, it is expected to replace conventional light emitters in many applications, such as traffic signals, outdoor and indoor displays, automotive headlights and taillights, and conventional indoor lighting devices. However, the conventional LED can not emit all the light generated in the active layer is limited in its efficiency.

1 is a cross-sectional view of a light emitting diode device having a conventional mesh-shaped ohmic electrode. After the N-type semiconductor layer 20, the active layer 30, and the P-type semiconductor layer 40 are sequentially stacked on the substrate 10, a mesh-shaped ohmic electrode 50 is formed. Here, the mesh shape is a structure having an opening so that at least a part of the P-type semiconductor layer 40 is exposed. If the transmissive electrode (TP metal: TP metal) is formed without forming the ohmic electrode 50 having the opening in the P-type semiconductor layer 40, the LED is driven to generate the light generated in the active layer 30. Part is reflected from the P-type semiconductor 40 layer and the transparent electrode. Even though a part of the light penetrates the transparent electrode, the light generated in the active layer 30 is light in the visible ray region of about 4000 파장 wavelength, so the boundary condition is not satisfied in the transmissive electrode of about tens to hundreds of thin thickness. Therefore, light loss occurs. Therefore, when the ohmic electrode 50 having the opening is applied, since the light is directly transmitted from the opening to the atmosphere or epoxy and emitted to the outside, the optical loss is reduced.

While the LED having the ohmic electrode 50 has the above advantages, the LED has the following problems. Since the refractive index of typical semiconductor materials is about 2.2-3.8, it has a higher value than the atmosphere (n = 1.0) or the encapsulating epoxy (n) 1.5). According to Snell's law, light traveling from a region of high refractive index to a region having a lower refractive index at an angle larger than a certain critical angle (normal reference) does not transmit to the outside but is 100% reflected inside, that is, internal total reflection ( Total Internal Reflection (TIR). Therefore, some of the light emitted from the active layer 30 is totally reflected inside the P-type semiconductor layer 40 is not transmitted through the surface in contact with the atmosphere or epoxy and the light is continuously reflected in the LED until it is absorbed, Escape out of the surface, not the emitting surface. Therefore, a problem arises in that light extraction efficiency is lowered even in a light emitting diode device having a mesh-shaped ohmic electrode.

2 is a cross-sectional view of a light emitting diode device having a conventional rough surface semiconductor layer. The LED is roughened by random texturing on the P-type semiconductor layer 40. Light generated from the active layer 30 and reaching the rough surface is diffusely reflected in all directions according to the law of reflection. Therefore, as in the LED of FIG. 1, the light extraction efficiency is high because the internally reflected light is not guided along the surface.

However, when the transparent electrode 60 is applied to the rough surface semiconductor layer, the rough surface prevents the current from being dispersed from the wire bonding metal pad 70 to the semiconductor layer 40 and the active layer 30. Therefore, the carrier supply does not occur smoothly in the semiconductor layer, which causes a problem of lowering the light generation efficiency (Internal quantum efficiency).

The present invention has been made to solve the above problems, and an object thereof is to provide a high brightness light emitting diode device capable of increasing light extraction efficiency and light generation efficiency.

In order to achieve the above object, a light emitting diode device according to an embodiment of the present invention, a substrate; N-type semiconductor layer; An active layer for generating light; A light emitting diode device comprising: a first exposure surface exposing at least a portion of the N-type semiconductor layer by etching the active layer and the P-type semiconductor layer; A first ohmic electrode formed on the first exposure surface; A mesh shape formed on the P-type semiconductor layer, the opening having a portion of the P-type semiconductor layer having a second exposure surface, wherein at least one rectangular opening is repeatedly arranged in a lattice shape, and at least one Any one of the shapes selected from the mesh shape in which the above-described trapezoidal openings are repeatedly arranged radially or the mesh shape in which zigzag branches extend in the direction of the first ohmic electrode about the opposite corner of the diagonal direction of the first ohmic electrode. A second ohmic electrode having; Random texturing is performed on the second exposed surface, which is the P-type semiconductor layer except for the first exposed surface and the second ohmic electrode forming surface, except the surface on which the first ohmic electrode is to be formed, and the first exposure surface and the P-type semiconductor are formed. Ag, Al, Au, Cr, In, Ir, Ni, Pd, Pb, Pt, Rd, Sn, Ti, W or a combination of these metals are applied to the layer and heat treated at high temperature to form metal clusters. Through the photolithography process, to remove the metal mass in the portion where the first ohmic electrode is formed on the first exposure surface and the portion where the second ohmic electrode is formed in the P-type semiconductor layer, and dry or wet using the remaining metal mass Etching includes the first exposure surface and the second exposure surface other than the formation surface of the first ohmic electrode is rough, and is formed on the second exposure surface and the second ohmic electrode of the P-type semiconductor layer Light directed from the active layer toward the semiconductor layer A flip chip bonding electrode which reflects the light to the surface; A conductive material bonded to the flip chip bonding electrode and conducting current and heat; It is bonded to the conductive material, characterized in that consisting of a sub-mount to transfer the current in the direction of the N-type semiconductor and to discharge the heat generated in the active layer to the outside.

Preferably, the first exposure surface except for the formation surface of the first ohmic electrode is random texturized.
According to the present invention, the random texturing treatment is performed on the second exposure surface, which is a P-type semiconductor layer except for the first exposure surface and the surface on which the second ohmic electrode is to be formed, except for the surface on which the first ohmic electrode is to be formed. Ag, Al, Au, Cr, In, Ir, Ni, Pd, Pb, Pt, Rd, Sn, Ti, W or a combination of these metals are applied to the exposed surface and the P-type semiconductor layer, and then heat-treated at a high temperature. Forming a metal cluster; Removing a metal lump in a portion where the first ohmic electrode is formed on the first exposure surface and a portion where the second ohmic electrode is formed in the P-type semiconductor layer through a photolithography process; Drying or wet etching using the remaining metal agglomerates to roughly form the first exposure surface and the second exposure surface except for the formation surface of the first ohmic electrode.

According to the present invention, the second ohmic electrode has a mesh shape in which at least one or more rectangular openings are repeatedly arranged in a lattice shape, and the mesh shape or at least one trapezoidal opening is repeatedly arranged in a radial shape or the first ohmic electrode. It may be any one shape selected from among a mesh shape in which a zigzag branch extends in the direction of the first ohmic electrode with respect to the opposite corner of the diagonal direction.

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According to the present invention, the second ohmic electrode has a mesh shape extending outwardly in a spider web shape centering on the center of the P-type semiconductor layer, and the first ohmic electrode has a closed curve shape surrounding the P-type semiconductor layer. Can be.
In accordance with another aspect of the present invention, a light emitting diode device includes a substrate; N-type semiconductor layer; An active layer for generating light; P-type semiconductor layer; Transmissive electrodes; A first pad comprising a metal pad for wire bonding, wherein the active layer and the P-type semiconductor layer are etched to expose at least a portion of the N-type semiconductor layer; And a first ohmic electrode formed on the first exposed surface, wherein the first exposed surface except for the forming surface of the first ohmic electrode is randomly textured.

In accordance with another aspect of the present invention, a light emitting diode device includes a substrate; N-type semiconductor layer; An active layer for generating light; P-type semiconductor layer; Transmissive electrodes; A first pad comprising a metal pad for wire bonding, wherein the active layer and the P-type semiconductor layer are etched to expose at least a portion of the N-type semiconductor layer; And a first ohmic electrode formed on the first exposed surface, wherein the first exposed surface except for the forming surface of the first ohmic electrode is randomly textured.

According to the present invention, the P-type semiconductor layer is gallium nitride (GaN) doped with magnesium (Mg), the N-type semiconductor layer is gallium nitride (GaN) doped with silicon (Si), and the active layer is gallium nitride (GaN).

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Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

3 is a schematic perspective view of a light emitting diode device according to an exemplary embodiment of the present invention, and FIG. 4A is a cross-sectional view taken along the direction S1 of FIG. 3.

Referring to FIG. 3, in order to implement an embodiment of the present invention, an N-type semiconductor layer 20, an active layer 30, and a P-type semiconductor layer are first applied by applying an epitaxial process on a predetermined substrate 10. 40 is formed. Substrate 10 may be a light transmissive sapphire substrate may be used. The N-type semiconductor layer 20 is formed of gallium nitride (GaN) doped with silicon (Si), and the P-type semiconductor layer 40 is formed of gallium nitride (GaN) doped with magnesium (Mg). However, the present invention is not limited thereto. As the active layer 30, gallium nitride (GaN), gallium aluminum nitride (AlGaN), and gallium indium nitride (InGaN) are mainly used. The amount of aluminum (Al) and indium (In) may be adjusted according to the type of light.

Subsequently, in order to expose the N-type semiconductor layer 20, a portion of the active layer 30 and the P-type semiconductor layer 40 are etched by applying a photo lithography process. Then, the first exposure surface A1 is formed on the N-type semiconductor layer 20. Preferably, the edges of the active layer 30 and the P-type semiconductor layer 40 are etched to form a first exposure surface A1 on the outer circumference of the N-type semiconductor layer 20. Then, in order to form the first ohmic electrode 50a at one corner on the N-type semiconductor layer 20, one corner of the first exposure surface A1 has an approximately rectangular surface so as to have an active layer 30 and P. The mold semiconductor layer 40 is etched.

Thereafter, random texturing is performed on the first and second exposed surfaces A1 and A2 except for the surface on which the first ohmic electrode 50a is to be formed. Here, the second exposure surface A2 is a P-type semiconductor layer 40 except for the formation surface of the second ohmic electrode 50b and includes a surface exposed to the outside through the opening of the second ohmic electrode 50b.

Random texturing is a process of making a surface rough. There are several ways to create a random texturing structure, where N-type metals (Ag, Al, Au, Cr, In, Ir, Ni, Pd, Pb, Pt, Rd, Sn, Ti, W, or a combination thereof) are N-type. Metal clusters are formed by coating the first exposed surface A1 and the P-type semiconductor layer 40 of the semiconductor layer 20 and performing heat treatment at a high temperature. Then, a metal mass in a portion of the first exposed surface A1 where the first ohmic electrode 50a is formed and in the portion of the P-type semiconductor layer 40 where the second ohmic electrode 50b is formed through the photolithography process. After removal, the first exposed surface A1 and the second exposed surface A2 may be roughened except for the forming surface of the first ohmic electrode 50a by dry or wet etching using the remaining metal mass.

Alternatively, after the silicon mixture (SiO ₂ , Si ₃ N ₄ ) is grown roughly on the surface by a method such as porous growth, the first exposure except for the portion where the first ohmic electrode 50a is to be formed by the photolithography method. There is also a method of etching the surface A1 and the second exposed surface A2 by ICP, RIE, or the like.

In addition, a silicon mixture (SiO 2, Si ₃ N ₄ ) is grown, and metals (Ag, Al, Au, Cr, In, Ir, Ni, Pd, Pb, Pt, Rd, Sn, Ti, W or metals in combination thereof ) To form a metal cluster by heat treatment at a high temperature, and then the first exposure surface A1 except for a portion where the first ohmic electrode 50a is to be formed through the photolithography process using the metal mass. ) And the second exposure surface A2 may be selectively etched (Wet and dry).

The reason of the random texturing is to diffuse the photons generated in the active layer 30 on the first exposure surface A1 and the second exposure surface A2, which will be described later with reference to FIG. 4A. Do it.

Since the ohmic electrodes 50a and 50b are formed on the N-type and P-type semiconductor layers as described above, and then random texturing is performed, the bottom surfaces of the first ohmic electrode 50a and the second ohmic electrode 50b still maintain smooth surfaces. do. Although the material of the ohmic electrodes 50a and 50b may be formed of Ti, Al, Au, Ni, Pt, Pd, Ag, Rh or a mixture thereof, a white metal such as Al, Pt, Cr may be used. The reflectance can be increased.

After random texturing on the N-type and P-type semiconductor layers as described above, a first ohmic electrode 50a is formed at one corner of the first exposure surface A1 through a photolithography process, and the P-type semiconductor layer 40 Is formed on the second ohmic electrode 50b.

At this time, the second ohmic electrode 50b is formed in a mesh shape having an opening, where the mesh shape is a name encompassing a network structure having an opening, and a lattice pattern as shown in FIG. 3 is a representative mesh shape. Specific and various embodiments of the mesh shape will be described later with reference to FIGS. 5A to 5D.

The above is a method of random texturing the upper surfaces of the N-type semiconductor layer 20 and the P-type semiconductor layer 40 except for the portion where the ohmic electrodes 50a and 50b are to be formed before the ohmic electrodes 50a and 50b are formed. This is the description. However, first, the ohmic electrodes 50a and 50b may be formed, and then random texturing may be performed on the top surfaces of the N-type semiconductor layer 20 and the P-type semiconductor layer 40 except for the portions where the ohmic electrodes 50a and 50b are formed. In this case, the ohmic electrode acts as an aligner itself.

Through the above process, a light emitting diode device according to an embodiment of the present invention is manufactured.

Referring to FIG. 4A, a principle of high brightness of a light emitting diode device according to an exemplary embodiment will be described. Like the device shown in FIG. 3, the substrate 10, the N-type semiconductor layer 20, the active layer 30, the P-type semiconductor layer 40, the first ohmic electrode (not shown), and the second ohmic electrode 50b are formed. Equipped.

A first ohmic electrode (not shown) is formed on the first exposure surface A1 of the N-type semiconductor layer 20, and the first exposure surface A1 of the N-type semiconductor layer 20 is the first ohmic. Random texturing is performed on portions other than the surface on which electrodes (not shown) are formed. The P-type semiconductor layer 40 is also subjected to random texturing on the second exposed surface A2.

When a wire is attached to both the first ohmic electrode (not shown) and the second ohmic electrode 50b, and a bias voltage is applied to both ends, electrons and holes are respectively formed of the first ohmic electrode (not shown) and the second ohmic electrode 50b. Is introduced into the active layer 30 through, the light is generated as the electrons and holes are combined in the active layer 30. The light is emitted in all directions, and the light is directly emitted to the outside through the exposed surfaces A1 and A2 of the semiconductor layer, and the bottom of the first ohmic electrode (not shown) or the second ohmic electrode 50b. Reflected by, it is guided in the device and emitted to the outside.

Of the light emitted in all directions, the light incident at an angle greater than the critical angle based on the normal direction is totally reflected internally (TIR), but the N-type semiconductor layer 20 and P of the light emitting diode according to an embodiment of the present invention. Since the surface of the mold semiconductor layer 40 is random texturing, light is transmitted through the diffuse reflection without diffused reflection (TIR) even when incident at an angle greater than the critical angle.

Of course, the light that is totally reflected on the smooth side as in the conventional invention may be guided from the inside to be emitted to the outside through the other side, but the amount of light emitted to the outside due to light loss occurs during the guiding process inside Less. Therefore, the light extraction efficiency is higher than that of the smooth surface because a large amount of light is diffused by rough reflection on the rough surface.

In addition, the second ohmic electrode 50b has an opening, and the bottom surface of the second ohmic electrode 50b has a smooth structure. Since the random texturing treatment is performed only on the second exposed surface A2 of the P-type semiconductor layer exposed through the opening, the second ohmic electrode 50b is not affected by the rough surface. Therefore, the problem of poor current dispersion on the rough surface does not occur in the present invention.

In other words, while the second ohmic electrode 50b is applied to the semiconductor layer 40 having a rough surface, the bottom surface of the second ohmic electrode 50b has a smooth structure, so that the carrier supplied from the outside flows smoothly. Therefore, the light generation efficiency due to the combination of electrons and holes also increases.

On the other hand, when a white metal such as Al, Pt, Cr is used as the material of the electrode in order to increase the reflectance on the bottom surface of the first ohmic electrode (not shown) second ohmic electrode 50b having a smooth structure, it is generated in the active layer. As a result, the amount of light that is incident on the bottom surface of the first ohmic electrode (not shown) or the second ohmic electrode 50b and then reflects back inside increases. In this case, the amount of light emitted to the outside through the other surface of the reflected light also increases, thereby increasing the light extraction efficiency.

The light emitting diode device according to the present invention has the characteristics of high brightness because the light extraction efficiency and the light generation efficiency is high in the same principle as above.

4B is a cross-sectional view of a light emitting diode device according to another embodiment of the present invention. Comparing the light emitting diode device shown in FIG. 4B with the light emitting diode device shown in FIG. 4A, the P-type semiconductor layer 40 is not subjected to random texturing, and instead of the second ohmic electrode, the light-transmitting electrode 60 and the wire bonding may be used. The metal pad 70 is formed. 4A, random texturing is performed on the first exposed surface A1 other than the surface on which the ohmic electrode 50a of the N-type semiconductor layer 20 is formed.

According to the present embodiment, the light incident on the P-type semiconductor layer 40 at an angle greater than the critical angle is totally reflected from the light-transmitting electrode 60 to the inside, but is reflected back from the inside of the light to the N-type semiconductor at an angle greater than the critical angle. Light incident on the layer 20 is diffusely reflected and emitted to the outside.

That is, in this embodiment as well, as in the embodiment shown in FIG. 4A, the bottom surface of the first ohmic electrode 50a has a smooth shape. Therefore, the light incident on the bottom surface is reflected inside and then emitted to the outside to emit light. Contribute to.

Hereinafter, various types of second ohmic electrodes 50b according to embodiments of the present invention will be described with reference to FIGS. 5A to 5D.

5A, 5B, 5C and 5D are top plan views of a light emitting diode device according to an embodiment of the present invention.

Referring to FIG. 5A, the first ohmic electrode 50a is formed at one corner on the first exposure surface A1 of the N-type semiconductor layer 20, and the mesh-shaped material is formed on the P-type semiconductor layer 40. 2 ohmic electrodes 50b are formed. The second ohmic electrode 50b has an opening such that the P-type semiconductor layer 40 has the second exposure surface A2, and the openings are arranged in a rectangular lattice pattern. Here, the second ohmic electrode 50b may include a portion having no opening in a predetermined area on the opposite side in the diagonal direction of the corner where the first ohmic electrode 50a is formed. This is a portion for bonding wires in order to apply a bias voltage to the portion having no opening and the first ohmic electrode 50a.

Since random texturing is performed on the first exposure surface A1 and the second exposure surface A2 excluding the formation surface of the first ohmic electrode 50a, light incident at an angle greater than a critical angle is also diffusely reflected. Is released to the outside.

Referring to FIG. 5B, the first ohmic electrode 50a is formed at one corner on the first exposure surface A1 of the N-type semiconductor layer 20, and has a mesh-shaped second shape that spreads radially from the other corner. The ohmic electrode 50b is formed. The opening shape of the second ohmic electrode 50b has a trapezoidal shape, specifically, two opposite sides of the trapezoid have a fan shape, and two opposite sides of the second ohmic electrode 50b have a tapered straight shape.

In addition, as in the embodiment shown in FIG. 5A, the second ohmic electrode 50b preferably includes a portion having no opening in a predetermined area on the opposite side to the diagonal direction of the corner where the first ohmic electrode 50a is formed.

It is preferable that the said trapezoid is arranged radially from the part without the said opening part, and the said trapezoid opening part is arrange | positioned so that the right side of a linear form may mutually shift | deviate. This may cause light to be guided along a straight line when arranged in a straight line. When the straight line is shifted, the light to be guided may be reduced to increase light extraction efficiency.

As the first ohmic electrode 50a is closer to the first ohmic electrode 50a from the portion without the opening, the size of the trapezoidal opening may be increased, so that current distribution may be evenly distributed.

The second ohmic electrode 50b illustrated in FIG. 5C has a zigzag branch extending from the opposite corner of the first ohmic electrode 50a in the direction of the first ohmic electrode 50a. The corner has a polygon with no opening in a certain area for wire bonding.

The second ohmic electrode 50b shown in FIG. 5D extends outwardly in a spider web shape centering on the center of the P-type semiconductor layer 40. Here, spider web refers to a shape in which a radially extending line intersects with a plurality of substantially concentric arcs.

Since the polygon without the opening is formed in the center of the P-type semiconductor layer 40, the first ohmic electrode 50a is formed in a closed curve surrounding the P-type semiconductor layer 40 on the first exposure surface A1. desirable.

6 is a cross-sectional view of a light emitting diode device having a flip chip structure according to an embodiment of the present invention. The light emitting diode device shown in FIG. 6 is packaged in a flip chip structure in the light emitting diode device according to the exemplary embodiment of the present invention shown in FIG. 4A.

Looking at the structure, as in the light emitting diode device shown in Figure 4a, the substrate 10; N-type semiconductor layer 20; Active layer 30; P-type semiconductor layer 40; Second ohmic electrode 50b; First The ohmic electrode 50a is provided. The second ohmic electrode 50b is also a mesh shape having an opening. Further, a flip chip bonding electrode 80 is bonded to the second exposure surface A2 and the second ohmic electrode 50b of the P-type semiconductor layer 40, and a conductive material 90; Conductive electrode 100; The sub mount 110 is formed sequentially.

The flip chip bonding electrode 80 reflects light generated in the active layer 30 and incident on the P-type semiconductor layer 40 in the direction of the semiconductor layer. White metals such as Pt and Al, which have high reflectances, are suitable, and a material that is easily combined with the conductive material 90 is preferable.

The conductive material 90 physically bonds the flip chip bonding electrode 80 and the conductive electrode 100 to conduct current and heat.

The conductive electrode 100 forms an ohmic contact with the submount 110 when the submount 110 is not a complete metal (eg, a Si wafer) to facilitate current flow. As the material of the conductive electrode 100, Ti / Au or Ti / Al metal or the like is used.

The sub-mount 110 serves to conduct current and emit heat to the outside, and is made of silicon wafer (Si wafer), Cu, Al, etc. having good electrical conductivity and thermal conductivity.

In the light emitting diode device having the flip-chip structure as described above, the light emitted from the active layer 30 to the exposed surface A2 of the P-type semiconductor layer 40 is again reflected on the P-type semiconductor on the flip-chip bonding electrode 80 with good reflectivity. Diffusely reflected into layer 40. Then, the light is emitted through the light-transmissive substrate 10 to the outside, or reflected back from the inside and diffused by the diffuse reflection on the exposed surface A1 of the N-type semiconductor layer 20 to the outside.

The light emitting diode device of the flip chip structure according to another embodiment of the present invention is similar to the light emitting diode device shown in FIG. 6, except that the second ohmic electrode 50b has a discontinuous dot shape. In the flip chip structure, since the flip chip bonding electrode 80 is bonded not only to the second ohmic electrode 50 b but also to the exposed surface A1 of the P-type semiconductor layer 40, the second ohmic electrode 50 b is discontinuous. Since the problem of current flow does not occur even after that, the dot-shaped ohmic electrode 50b is also possible.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is intended by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

According to an aspect of the present invention, by introducing a random texturing structure on the surface of the semiconductor layer it is possible to increase the light extraction efficiency of the light emitting diode device by increasing the light emitted by the diffuse reflection on the rough surface.

According to another aspect of the present invention, since the second ohmic electrode having the opening is not affected by the rough surface and thus smooth current distribution is possible, the light generation efficiency of the light emitting diode device can be improved.

According to another aspect of the present invention, the bottom surface of the second ohmic electrode is made smooth and the ohmic electrode is made of a material having high reflectance, thereby increasing the amount of light reflected from the formation surface of the P-type semiconductor layer and the second ohmic electrode. Therefore, the light extraction efficiency can be improved, and a high brightness light emitting diode device can be provided.

Claims (10)

Board; N-type semiconductor layer; An active layer for generating light; In the light emitting diode device comprising a P-type semiconductor layer, A first exposure surface on which the active layer and the P-type semiconductor layer are etched to expose at least a portion of the N-type semiconductor layer; A first ohmic electrode formed on the first exposure surface; A mesh shape formed on the P-type semiconductor layer, the opening having a portion of the P-type semiconductor layer having a second exposure surface, wherein at least one rectangular opening is repeatedly arranged in a lattice shape, and at least one Any one of the shapes selected from the mesh shape in which the above-described trapezoidal openings are repeatedly arranged radially or the mesh shape in which zigzag branches extend in the direction of the first ohmic electrode about the opposite corner of the diagonal direction of the first ohmic electrode. A second ohmic electrode having; Random texturing is performed on the second exposed surface, which is the P-type semiconductor layer except for the first exposed surface and the second ohmic electrode forming surface, except the surface on which the first ohmic electrode is to be formed, and the first exposure surface and the P-type semiconductor are formed. Ag, Al, Au, Cr, In, Ir, Ni, Pd, Pb, Pt, Rd, Sn, Ti, W or a combination of these metals are applied to the layer and heat treated at high temperature to form metal clusters. Through the photolithography process, to remove the metal mass in the portion where the first ohmic electrode is formed on the first exposure surface and the portion where the second ohmic electrode is formed in the P-type semiconductor layer, and dry or wet using the remaining metal mass Etching to roughen the first exposure surface and the second exposure surface except for the formation surface of the first ohmic electrode, A flip chip bonding electrode formed on the second exposure surface and the second ohmic electrode of the P-type semiconductor layer and reflecting light generated from the active layer toward the semiconductor layer; A conductive material bonded to the flip chip bonding electrode and conducting current and heat; And a sub mount bonded to the conductive material and transferring current toward the N-type semiconductor and dissipating heat generated in the active layer to the outside. delete delete delete delete The method of claim 1, The second ohmic electrode has a mesh shape extending outwardly in a spider web shape centering on the center of the P-type semiconductor layer, The first ohmic electrode is a light emitting diode device, characterized in that the closed curve surrounding the P-type semiconductor layer. delete delete The method of claim 1, The P-type semiconductor layer is gallium nitride (GaN) doped with magnesium (Mg), the N-type semiconductor layer is gallium nitride (GaN) doped with silicon (Si), and the active layer is gallium nitride (GaN). A light emitting diode device characterized by the above-mentioned. delete

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