KR101018936B1 - Large surface light emitting diode and method for fabricating the same - Google Patents

Abstract

The present invention relates to a large area light emitting diode and a method of manufacturing the same, wherein the grooves are etched to expose the sapphire substrate in some regions of the mesa etched N-type semiconductor layer between the plurality of light emitting region protrusions or in the inner region. By forming optical isolation parts by filling the reflective material in the grooves, the phenomenon in which light is trapped inside the device due to total reflection of light can be reduced, thereby increasing luminous efficiency.

Large area, light emitting diodes, light isolation, sidewalls, metal

Description

Large area light emitting diode and its manufacturing method {Large surface light emitting diode and method for fabricating the same}             

1 is a cross-sectional view of a large area light emitting diode according to the prior art.

FIG. 2 is a top view of FIG. 1

3a to 3e is a manufacturing process diagram of a large area light emitting diode according to the present invention

4 is a conceptual diagram illustrating a state in which light is emitted to the front through a substrate by an optical isolation part of a large area light emitting diode according to the present invention.

5 is a plan view of a state in which a light isolating portion is formed in a light emitting area according to the present invention;

6A to 6C are plan views of a state in which a plurality of light isolators are formed in a light emitting area according to the present invention.

7 is a schematic cross-sectional view showing the shape of an optical isolation portion according to the present invention.

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

100: sapphire substrate 110: N type semiconductor layer

115: active layer 120: P-type semiconductor layer                 

130a, 130b, 130c: light emitting region protrusion 140: groove

150,155: optical isolation section

160: N electrode 170a, 170b, 170c: P electrode

The present invention relates to a large area light emitting diode and a method of manufacturing the same. More particularly, a large area light emitting diode capable of reducing total reflection of light by forming an optical isolator between or inside the light emitting region and increasing luminous efficiency thereof It relates to a manufacturing method.

Recently, with the development of gallium nitride technology, the luminous efficiency of light emitting diodes has been greatly improved.

In addition, there are several attempts to implement high power light emitting diodes as light emitting diodes for illumination and display light sources.

Among them, a large area light emitting diode having a larger area than a light emitting diode commonly used has been developed, and this large area light emitting diode has been actively applied in various ways as a backlight and lighting of a display.

In addition, after forming a reflective film on the light emitting surface of the light emitting diode, the heat is better emitted by the reflecting film to the lower, thereby developing a flip chip light emitting diode to increase the light emitting efficiency.

Nevertheless, luminous efficiency still needs to be further improved to be used for lighting.

In particular, the efficiency of light emitted from the active layer region of the light emitting diode to the outside of the light emitting diode shows very low efficiency in light extraction efficiency.

Therefore, further research is required to increase the light extraction efficiency.

1 is a cross-sectional view of a large-area light emitting diode according to the prior art, in which an N-type semiconductor layer, an active layer, and a P-type semiconductor layer are sequentially formed on the sapphire substrate 10, and the N-type semiconductor layer in the P-type semiconductor layer. Mesa is etched to a portion of the plurality of light emitting region protrusions 14a, 14b, 14c, and 14d, and P is formed on each of the plurality of light emitting region protrusions 14a, 14b, 14c, and 14d. Electrodes 16a, 16b, 16c, and 16d are formed, and N electrodes 15 are formed on the mesa-etched N-type semiconductor layer 11.

Here, an active layer 12 and a P-type semiconductor layer 13 are formed in each of the plurality of light emitting area protrusions 14a, 14b, 14c, and 14d.

Since the large area light emitting diode configured as described above can emit light in the plurality of light emitting area protrusions, the light emitting area can be increased.

However, in such a large area light emitting diode, light emitted from the active layer 12 is emitted to the outside through the sapphire substrate 10, and the angle at which light is incident on the interface between the N-type semiconductor layer 11 and the sapphire substrate 10. Is more than the critical angle, the total reflection, the trapped inside the device has a problem that the luminous efficiency is lowered.

FIG. 2 is a top view of FIG. 1, in which P electrodes 16a, 16b, 16c, and 16d are formed on respective light emitting region protrusions, and N electrode 15 is mesa-etched N-type semiconductor layer 11. It is formed on the top.

The present invention provides a large-area light emitting diode and a method of manufacturing the same, which can reduce the total reflection of light by forming an optical isolator between or within the light emitting region to solve the above problems, thereby increasing the light emitting efficiency. There is a purpose.

According to a preferred aspect of the present invention, an N-type semiconductor layer, an active layer, and a P-type semiconductor layer are sequentially formed on a sapphire substrate;

Mesa is etched from the P-type semiconductor layer to a portion of the N-type semiconductor layer to form a plurality of light emitting region protrusions;

Grooves etched to expose the sapphire substrate are formed in some regions of the mesa-etched N-type semiconductor layer between the plurality of light emitting region protrusions;

Optical isolation portions formed by filling a reflective material in the grooves are formed;                         

An N electrode is formed on the optical isolation parts, and a P electrode is formed on each of the plurality of light emitting area protrusions.

Another preferred aspect for achieving the above object of the present invention comprises the steps of sequentially depositing an N-type semiconductor layer, an active layer and a P-type semiconductor layer on top of the sapphire substrate;

Mesa etching from the P-type semiconductor layer to a portion of the N-type semiconductor layer to form a plurality of light emitting region protrusions;

Etching a portion of the mesa-etched N-type semiconductor layer between the plurality of light emitting region protrusions to expose the sapphire substrate to form grooves;

Depositing a reflective material in the grooves to form optical isolation portions;

A method of manufacturing a large-area light emitting diode is provided, including forming an N electrode on a portion of an N-type semiconductor layer including an upper portion of the optical isolation parts, and forming a P electrode on each of the plurality of light emitting area protrusions. .

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

3A to 3E illustrate a manufacturing process of a large area light emitting diode according to the present invention, in which an N type semiconductor layer 110, an active layer 115, and a P type semiconductor layer 120 are sequentially stacked on the sapphire substrate 100. (FIG. 3A)

Thereafter, Mesa is etched from the P-type semiconductor layer 120 to a portion of the N-type semiconductor layer 110 to form a plurality of light emitting region protrusions 130a, 130b, and 130c (FIG. 3B).

Next, some regions of the mesa-etched N-type semiconductor layer 110 between the plurality of emission region protrusions 130a, 130b, and 130c are etched to expose the sapphire substrate 100 to form grooves 140. (FIG. 3C)

Subsequently, a reflective material is deposited inside the grooves 140 to form optical isolation portions 150. (FIG. 3D)

Finally, an N electrode 160 is formed on a portion of the N-type semiconductor layer including the light isolation parts 150, and a P electrode is formed on each of the plurality of light emitting area protrusions 130a, 130b, and 130c. 170a, 170b, and 170c are formed (FIG. 3E).

Thus, in the large area light emitting diode of the present invention, as shown in FIG. 3E, an N-type semiconductor layer, an active layer, and a P-type semiconductor layer are sequentially formed on the sapphire substrate 100; Mesa is etched from the P-type semiconductor layer to a portion of the N-type semiconductor layer to form a plurality of light emitting region protrusions 130a, 130b, and 130c; Etched grooves 140 are formed in some regions of the mesa-etched N-type semiconductor layer 110 between the plurality of emission region protrusions 130a, 130b, and 130c to expose the sapphire substrate 100. ; Optical isolation parts 150 formed by filling a reflective material in the grooves 140 are formed, and the N-electrode 160 is formed on a portion of the N-type semiconductor layer including an upper portion of the light isolation parts 150. P electrodes 170a, 170b, and 170c are formed on the plurality of light emitting area protrusions 130a, 130b, and 130c.

4 is a conceptual view illustrating a state in which light is emitted to the front surface through a substrate by an optical isolation part of a large area light emitting diode according to the present invention, wherein light emitted from the active layer of each light emitting area is a light emitting area protrusion. Since the light may be reflected by the optical isolation unit 150 existing between them, the light may pass through the sapphire substrate 100 and be emitted to the front surface of the substrate, thereby reducing the total reflection phenomenon.

In addition, as shown in FIG. 4, when the light isolator 155 is formed inside the light emitting area protrusions as the light emitting area, the light is better emitted to the front surface of the substrate, thereby reducing the total reflection phenomenon.

Therefore, the present invention has the advantage of reducing the total reflection of light by forming the light isolating portion between or within the light emitting region, thereby increasing the light emitting efficiency.

FIG. 5 is a plan view showing a light isolation portion formed in a light emitting region according to the present invention, wherein the light isolation portion 155 existing inside the light emitting region is mesa-etched from an inner region of the light emitting region protrusion to an N-type semiconductor layer. A portion of the etched N-type semiconductor layer 110 is etched to form a groove formed with a reflective material.

6A to 6C are plan views of a state in which a plurality of light isolators are formed in a light emitting area according to the present invention, and at least one light isolator may be formed inside the light emitting area, and FIGS. It is showing.

And the cut surface shape of the optical isolator is circular (155a, 155b) as shown in Figure 6a, squares (155c, 155d) as shown in Figure 6b, cross 155e as shown in Figure 6c, loop 155f and ring (155g), Moreover, the shape which synthesize | combined these is preferable.

7 is a schematic cross-sectional view showing the shape of the optical isolation unit according to the present invention. The sidewalls of the optical isolation unit 150 may be formed by etching at an inclined angle, and the inclined angle α ) Is preferably 45 to 85 °.

As a reflective material, a material with good reflectivity is used, and a high reflection coating can be applied to increase the reflectance. The reflectance shall be 50% or more.

In addition, in order to improve the electrical characteristics, it is preferable to use a metal having good conductivity and an ohmic contact with the n-type semiconductor.

As described above, the present invention can reduce the total reflection of the light by forming the light isolating portion between or inside the light emitting region has an excellent effect that can increase the light emitting efficiency.

Although the invention has been described in detail only with respect to specific examples, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims.

Claims (5)

An N-type semiconductor layer, an active layer and a P-type semiconductor layer are sequentially formed on the sapphire substrate; Mesa is etched from the P-type semiconductor layer to a portion of the N-type semiconductor layer to form a plurality of light emitting region protrusions; Grooves etched to expose the sapphire substrate are formed in some regions of the mesa-etched N-type semiconductor layer between the plurality of light emitting region protrusions; Optical isolation portions formed by filling a reflective material in the grooves are formed; A large area light emitting diode having an N electrode formed on a portion of an N-type semiconductor layer including an upper portion of the optical isolation parts, and a P electrode formed on each of the plurality of light emitting area protrusions. The method of claim 1, At least one optical isolation portion formed by mesa etching from an inner region of the light emitting region protrusion to an N-type semiconductor layer, wherein a metal is filled in a groove formed by etching a portion of the mesa-etched N-type semiconductor layer. The large area light emitting diode characterized by the above-mentioned further being formed. The method of claim 1, The side wall of the optical isolator, A large area light emitting diode, which is formed by etching at an inclination angle of 45 to 85 °. Sequentially stacking an N-type semiconductor layer, an active layer, and a P-type semiconductor layer on the sapphire substrate; Mesa etching from the P-type semiconductor layer to a portion of the N-type semiconductor layer to form a plurality of light emitting region protrusions; Etching a portion of the mesa-etched N-type semiconductor layer between the plurality of light emitting region protrusions to expose the sapphire substrate to form grooves; Depositing a reflective material in the grooves to form optical isolation portions; And forming an N electrode on a portion of the N-type semiconductor layer including the optical isolation parts, and forming a P electrode on each of the plurality of light emitting area protrusions. The method of claim 4, wherein The sidewalls of the grooves are formed by etching at an angle of inclination of 45 ~ 85 °.

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