KR101494668B1 - light emitting diodes periodically patterned in trarnsparent electrode - Google Patents

Abstract

A light emitting diode having a periodic pattern formed on a transparent electrode is disclosed. The light emitting diode includes a substrate, an n-type semiconductor disposed on the upper surface of the substrate, a negative electrode disposed on a part of the n-type semiconductor upper surface, a light emitting layer disposed on the n-type semiconductor except for a part of the region, A semiconductor, a transparent electrode arranged on the upper surface of the p-type semiconductor, and a positive electrode arranged on the upper surface of the transparent electrode. At this time, the transparent electrode may have a periodic pattern in which the same pattern is repeatedly etched repeatedly at the rim portion adjacent to the region where the negative electrode is disposed so as to expose the p-type semiconductor, or a region where the negative electrode is arranged to expose the p- A complete etch region etched away from the adjacent border by a certain distance and a periodic pattern extending from the complete etch region and repeatedly etched in the same shape are formed.

Description

[0001] The present invention relates to a light emitting diode having a periodic pattern in a transparent electrode,

The present invention relates to a light emitting diode having a periodic pattern formed on a transparent electrode. And more particularly, to a light emitting diode having a periodic pattern formed on a transparent electrode that improves a current density distribution by patterning a transparent electrode in an area where current is excessively drawn.

Light emitting diodes (LEDs) are semiconductor light emitting devices that convert current into light. Such a light emitting diode is widely used as a light source for a variety of devices such as a cellular phone, a camera flash, and an LCD backlight as well as an optical communication and an electronic device. Recently, a light emitting diode has been increasingly used as a light source for a display, . It is also possible to realize a light emitting diode that emits white light having high efficiency by using a fluorescent material or combining light emitting diodes of various colors.

As such a light emitting diode, a light emitting diode having a pn junction structure of a unidirectional vertical structure is widely used, and studies for solving the current density unbalance of the light emitting diodes are progressing steadily.

1 is a plan view of a general light emitting diode,

2 shows a cross-sectional view of a typical light emitting diode.

Referring to FIG. 1, the upper surface of the light emitting diode includes a positive electrode 64 disposed on the upper surface of the transparent electrode 50, and a negative electrode 62 disposed on the upper surface of the n-type semiconductor layer 20.

The negative electrode 62 includes a first pad portion disposed on a part of the upper surface of the n-type semiconductor 20 and a first finger portion extending from the first pad portion.

The positive electrode 64 includes a second pad portion disposed on a part of the upper surface of the transparent electrode 50 and a second finger portion extending from the second pad portion.

Referring to FIG. 2, the light emitting diode includes an n-type semiconductor 20, a p-type semiconductor 40, and a light emitting layer 30 disposed therebetween on a substrate 10 formed below.

The n-type semiconductor 20 and the p-type semiconductor 40 are respectively provided with a negative electrode 62 and a positive electrode 64 electrically connected to an external power source.

Accordingly, current flows from the p-type semiconductor 40 through the light emitting layer 30 to the n-type semiconductor 20 through the light emitting diode. Therefore, when a positive load is applied to the positive electrode 64 of the light emitting diode and a negative load is applied to the negative electrode 62, holes and electrons are emitted from the p-type semiconductor 40 and the n-type semiconductor 20, respectively, And recombine to emit light.

The excessive current density of such light emitting diodes reduces the internal quantum efficiency and reduces the luminous efficiency. In the case of a GaN-based light emitting diode, a transparent electrode film such as ITO is formed on the p-type GaN layer in order to diffuse current. In this case, even if a constant voltage is applied to the ITO film through the (+) metal electrode, a current crowding phenomenon occurs around the (-) metal electrode where the resistance is smallest. The internal quantum efficiency is decreased. In other regions, the current distribution is relatively low. In order to overcome this, the applied voltage is increased to generate heat. Therefore, there is a demand for a light emitting diode that improves the current density distribution to solve this problem.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light emitting diode in which a periodic pattern is formed on a transparent electrode for improving a current density distribution.

According to another aspect of the present invention, there is provided a light emitting diode having a periodic pattern formed on a transparent electrode to improve internal quantum efficiency and luminous efficiency.

According to an aspect of the present invention, there is provided a light emitting diode having a periodic pattern formed on a transparent electrode according to an embodiment of the present invention includes a substrate, an n-type semiconductor disposed on an upper surface of the substrate, A p-type semiconductor disposed on an upper surface of the light emitting layer, a transparent electrode disposed on an upper surface of the p-type semiconductor, and a positive electrode disposed on an upper surface of the transparent electrode, A periodic pattern in which the same shape is repeatedly etched may be formed at a rim portion adjacent to the region where the negative electrode is disposed to expose the p-type semiconductor.

According to another embodiment of the present invention, there is provided a light emitting diode comprising a substrate, an n-type semiconductor disposed on an upper surface of the substrate, a negative electrode disposed on a part of the n-type semiconductor upper surface, Type semiconductor disposed on the upper surface of the light emitting layer, a transparent electrode disposed on the upper surface of the p-type semiconductor, and a positive electrode disposed on the upper surface of the transparent electrode, wherein the transparent electrode is arranged so as to expose the p- A complete etch region etched away by a distance from the border adjacent to the etched region and a periodic pattern extending from the etch region and repeatedly etched in the same pattern may be formed.

In addition, the periodic pattern according to the present invention is formed continuously with a triangular or trapezoidal shape, wherein the triangular periodic pattern has a width of 2 탆 to 200 탆 and a length of 2 탆 to 200 탆, and a trapezoidal periodic pattern has a width of 1um ~ 100um long and 2um ~ 200um long and 2um ~ 200um long.

In addition, the periodic pattern according to the present invention has a rectangular shape, is intermittently formed intermittently, has a width of 1 탆 to 200 탆, and a length of 1 탆 to 200 탆.

In addition, the periodic pattern according to the present invention has a semi-circular shape, semi-elliptic shape, or arc shape, and is formed continuously, having a width of 2 袖 m to 200 袖 m and a length of 1 袖 m to 100 袖 m.

In addition, the periodic pattern according to the present invention has a lattice shape and is continuously formed. The line segments having a thickness of 1 to 200 [mu] m are formed in the lattice shape with a certain interval, the vertical width between lattices is 1 [mu] The horizontal width between the grids is 1 to 200 μm.

In addition, the width or length of the periodic pattern according to the present invention may be constant, gradual, or irregular.

According to the light emitting diode having the periodic pattern formed on the transparent electrode according to the present invention, a periodic pattern in which the same shape is repeatedly etched is formed on the transparent electrode in the vicinity of the current is excessively drawn, thereby adjusting the resistance component of the transparent electrode, It is possible to provide a light emitting diode that can solve the problem.

Also, it is possible to provide a light emitting diode capable of increasing the internal quantum efficiency and luminous efficiency by patterning the transparent electrode with a periodic structure.

1 is a plan view of a general light emitting diode,
2 is a cross-sectional view of a general light emitting diode.
3 is a plan view of a light emitting diode according to a first embodiment of the present invention.
4 is a cross-sectional view of a light emitting diode structure according to a first embodiment of the present invention.
FIG. 5A is a diagram illustrating a triangular periodic pattern according to the first exemplary embodiment of the present invention. FIG.
5B is a view showing a rectangular pattern in a rectangular shape according to the first embodiment of the present invention.
FIG. 5C is a diagram showing a periodic pattern of a semicircular shape according to the first embodiment of the present invention. FIG.
5D is a diagram illustrating a periodic pattern in the form of a lattice according to the first embodiment of the present invention.
6 is a plan view of a light emitting diode according to a second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather obvious or understandable to those skilled in the art.

3 is a plan view of a light emitting diode according to a first embodiment of the present invention.

3, the negative electrode 62 includes a negative electrode pad portion 62a disposed on a part of the upper surface of the n-type semiconductor 20 and a negative electrode fingering portion 62b extending from the negative electrode pad portion 62a.

The positive electrode 64 includes a positive electrode pad portion 64a disposed on a part of the upper surface of the transparent electrode 50 and a positive electrode fingering portion 64b extending from the positive electrode pad portion 64a.

The transparent electrode 50 of the light emitting diode forms a periodic pattern P1 in which the same shape is repeatedly etched at the edge portion adjacent to the region where the cathode electrode 62 is disposed so as to expose the p-type semiconductor.

The periodic pattern P1 has a triangular or trapezoidal shape and is formed continuously. The triangular periodic pattern has a width of 2 um to 200 um and a length of 2 um to 200 um, wherein the trapezoidal periodic pattern has a short width of 1 um to 100 um, a long width of 2 um to 200 um, and a length of 2 um to 200 um.

The periodic pattern P1 has a rectangular shape and is formed intermittently and spaced apart from each other. The periodic pattern of a rectangular shape has a width of 1 to 200 μm and a length of 1 to 200 μm.

The periodic pattern P1 has a semi-circular shape, a semi-elliptical shape, and an arc shape, and is formed continuously. Semicircular, semi-elliptical, and arc-shaped periodic patterns are 2 to 200 μm wide and 1 to 100 μm long.

The periodic pattern P1 has a lattice shape and is formed continuously. In the periodic pattern, a line segment having a thickness of 1 to 200 .mu.m has a predetermined interval and has a lattice shape. The vertical width between the lattices is 1 to 200 .mu.m, and the width between the lattices is 1 to 200 .mu.m.

In the case where the patterning is not performed, the current is excessively concentrated at the edge portion of the transparent electrode 50 having the shortest reach distance from the negative electrode 62, adjacent to the region where the negative electrode is disposed. However, in the case of patterning, the ratio of the transparent electrode at the edge portion is lowered. This can increase the resistance of the rim portion of the transparent electrode 50 and reduce the amount of current that is excessively crowded at the rim portion of the transparent electrode 50. This can distribute the current of the diode to evenly distribute the density density.

4 is a cross-sectional view of a light emitting diode structure according to a first embodiment of the present invention.

4, the light emitting diode includes a substrate 10, an n-type semiconductor 20 disposed on the upper surface of the substrate 10, a negative electrode 62 disposed on a part of the upper surface of the n-type semiconductor 20, A light emitting layer 30 disposed on the upper surface of the n-type semiconductor 20 except for a part of the region, a p-type semiconductor 40 disposed on the upper surface of the light emitting layer 30, and a transparent electrode 50 And a positive electrode 64 disposed on the upper surface of the transparent electrode 50.

The light emitting diode portion may be formed by successively growing an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer on a base base by a method such as metal organic chemical vapor deposition (MOCVD). At this time, the n-type layer, the active layer and the p-type layer may be formed using a conventional gallium nitride compound known in the art such as GaN, GaAIN, InGaN, InAlGaN or a mixture thereof. In addition, the active layer may be a single quantum well structure or a multiple quantum well structure (MQW). And may include a buffer layer other than the above-described p-type semiconductor layer, light emitting layer, and n-type semiconductor layer. By controlling the composition ratio of the gallium nitride compound, light emitting diodes ranging from a long wavelength to a short wavelength can be freely manufactured and applied to all light emitting diodes.

That is, the substrate 10, the n-type semiconductor layer 20, the light emitting layer 30, and the p-type semiconductor layer 40 are sequentially deposited using a metal organic chemical vapor deposition method. A positive electrode 64 for applying a voltage to the surface of the p-type semiconductor layer 40 is formed. Also, the light emitting diode is etched from the surface of the p-type semiconductor layer to a portion of the n-type semiconductor layer, and then the negative electrode 62 is formed.

FIG. 5A is a diagram illustrating a triangular periodic pattern according to the first exemplary embodiment of the present invention. FIG.

Referring to FIG. 5A, a triangular-shaped periodic pattern is formed by successively forming a triangular shape. The width W of the triangular periodic pattern is 2 to 200 μm and the length S is 2 to 200 μm. In addition, when the length of the short width Wo occurs in the triangular periodic pattern, it becomes a trapezoid. The periodic pattern of the trapezoidal shape has a short width Wo of 1 to 100 μm, a long width W of 2 to 200 μm and a length S of 2 to 200 μm. The width or length of the triangular periodic pattern changes constantly, progressively or irregularly.

5B is a view showing a rectangular pattern in a rectangular shape according to the first embodiment of the present invention.

Referring to FIG. 5B, the rectangular pattern is formed by intermittently spacing the rectangular patterns. The width W of the periodic pattern in the rectangular shape is 1 to 200 μm, and the length S is 1 to 200 μm. The width or length of the periodic pattern of the rectangular shape may be constant, gradual or irregular.

FIG. 5C is a diagram showing a periodic pattern of a semicircular shape according to the first embodiment of the present invention. FIG.

Referring to FIG. 5C, the semicircular periodic pattern is formed in a semicircular shape continuously. The semicircular periodic pattern has a width W of 2 to 200 μm and a length S of 1 to 100 μm. It can also have semi-elliptical or arc form as well as semicircular form. The width or length of the periodic pattern of any one of semicircular, semi-elliptic, and arc shapes may be constant, gradual, or irregular.

5D is a diagram illustrating a periodic pattern in the form of a lattice according to the first embodiment of the present invention.

Referring to FIG. 5D, the periodic pattern in a lattice form has a lattice shape and is formed continuously. The periodic pattern of the lattice form is a lattice shape with a constant interval of the segments having a thickness t of 1 μm to 200 μm. In addition, the vertical width W1 between the lattices is 1 um to 200 um, and the lateral width W2 between the lattices is 1 um to 200 um.

6 is a plan view of a light emitting diode according to a second embodiment of the present invention.

6, the negative electrode 62 includes a negative electrode pad portion 62a disposed on a part of the upper surface of the n-type semiconductor 20 and a negative electrode fingering portion 62b extending from the negative electrode pad portion 62a.

The positive electrode 64 includes a positive electrode pad portion 64a disposed on a part of the upper surface of the transparent electrode 50 and a positive electrode fingering portion 64b extending from the positive electrode pad portion 64a.

The transparent electrode 50 of the light emitting diode is formed with a complete etch region P2 that is etched at a distance from the edge adjacent to the region where the negative electrode 62 is disposed so as to expose the p-type semiconductor, Lt; / RTI >

The transparent electrode 50 also extends from the complete etching region P2 to form a periodic pattern P1 in which the same shape is repeatedly etched.

The periodic pattern P1 may be formed on all or only a part of the edge portion adjacent to the region where the cathode electrode 62 is disposed. The periodic pattern P1 may be formed on all or only a part of the rim portion adjacent to the region where the negative electrode 62 is disposed, depending on the design of the electrode and the pad.

Further, the shape and the specific dimensions of the periodic pattern P1 are the same as those of the first embodiment described above, so a detailed description thereof will be omitted

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation in the embodiment in which said invention is directed. It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the appended claims.

10: substrate
20: n type semiconductor
30: light emitting layer
40: p-type semiconductor
50: transparent electrode
62: negative polarity
62a: negative electrode pad portion
62b:
64: positive polarity
64a: positive electrode pad portion
64b:

Claims (11)

Type semiconductor; a light-emitting layer disposed on an upper surface of the n-type semiconductor excluding the partial region; and a p-type semiconductor layer disposed on the upper surface of the light- Type semiconductor, a transparent electrode arranged on the upper surface of the p-type semiconductor, and a positive electrode arranged on the upper surface of the transparent electrode,
The transparent electrode may be formed in a periodic pattern formed continuously and repeatedly in the same shape at the edge portion of the etched electrode to expose the p-type semiconductor,
Wherein a width or a length of the periodic pattern is constant, gradually or irregularly changed.
Type semiconductor; a light-emitting layer disposed on an upper surface of the n-type semiconductor excluding the partial region; and a p-type semiconductor layer disposed on the upper surface of the light- Type semiconductor, a transparent electrode arranged on the upper surface of the p-type semiconductor, and a positive electrode arranged on the upper surface of the transparent electrode,
The transparent electrode may include a complete etch region etched away from the etched rim to arrange the negative electrode and a periodic pattern extending continuously from the complete etch region to be repeated in the same pattern to expose the p- And,
Wherein a width or a length of the periodic pattern is constant, gradually or irregularly changed.
3. The method according to claim 1 or 2,
Wherein the periodic pattern has a triangular or trapezoidal shape and is continuously formed.
The method of claim 3,
Wherein the triangular periodic pattern has a width of 2 um to 200 um and a length of 2 um to 200 um,
Wherein the periodic pattern of the trapezoidal shape has a short width of 1 um to 100 um, a long width of 2 um to 200 um, and a length of 2 um to 200 um.
3. The method according to claim 1 or 2,
Wherein the periodic pattern has a rectangular shape and is intermittently spaced apart from each other.
6. The method of claim 5,
Wherein the periodic pattern has a width of 1 um to 200 um and a length of 1 um to 200 um.
3. The method according to claim 1 or 2,
Wherein the periodic pattern has one of a semi-circular shape, a semi-elliptical shape, and an arc shape, and is formed continuously.
8. The method of claim 7,
Wherein the periodic pattern has a width of 2 to 200 [mu] m and a length of 1 to 100 [mu] m.
3. The method according to claim 1 or 2,
Wherein the periodic pattern has a lattice shape and is formed continuously. A light emitting diode having a periodic pattern formed on a transparent electrode.
10. The method of claim 9,
Wherein the periodic pattern has a line segment having a thickness of 1 to 200 [mu] m at a predetermined interval and has a lattice shape, a vertical width between lattices of 1 [mu] m to 200 [mu] m, and a lateral width between lattices of 1 [ A light emitting diode in which a periodic pattern is formed on an electrode.
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