KR100762004B1 - Method of manufacturing nitride light emitting diode device - Google Patents

Abstract

A method for fabricating a nitride-based LED(light emitting diode) device is provided to improve light extraction efficiency by eliminating the need for limiting the size and shape of a pattern and by forming a pattern on the light emitting surface of a device by an imprint method. An n-type nitride semiconductor layer(120), an active layer(130) and a p-type nitride semiconductor layer(140) are sequentially formed on a substrate. A p-type electrode(150) is formed on the p-type nitride semiconductor layer. A structure support layer(200) is formed on the p-type electrode. The substrate is removed to expose the surface of the n-type nitride semiconductor layer. A transparent conductive polymer layer(170) is formed on the exposed n-type nitride semiconductor layer. A stamp having a pattern of a predetermined shape is pressurized to the transparent conductive polymer layer to transcribe the pattern to the surface of the transparent conductive polymer layer. The transparent conductive polymer layer having the transcribed pattern is hardened. The stamp is separated from the hardened transparent conductive polymer layer. An n-type electrode(160) is formed on the transparent conductive polymer layer. The transparent conductive polymer layer can be made of one of a group composed of PEDOT(poly ethylene dioxy thiophene), polypyrrole and polyaniline.

Description

Method of manufacturing nitride-based light emitting diode device

1 is a cross-sectional view showing the structure of a vertical nitride-based LED device according to the prior art.

2A to 2F are cross-sectional views sequentially illustrating a method of manufacturing a nitride-based LED device according to a first embodiment of the present invention.

3A to 3F are cross-sectional views sequentially illustrating a method of manufacturing a nitride-based LED device according to a second embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

100: transparent substrate 110: buffer layer

120: n-type nitride semiconductor layer 130: active layer

140: p-type nitride semiconductor layer 150: p-type electrode

160: n-type electrode 170: transparent conductive polymer layer (transparent polymer layer)

200: structural support layer 300: stamp

The present invention relates to a method for manufacturing a nitride-based light emitting diode device, and more particularly, to a method for manufacturing a nitride-based LED device to improve the light extraction efficiency.

In general, a light emitting diode is a semiconductor light emitting device capable of realizing various colors of light by forming a light emitting source by changing compound semiconductor materials such as GaAs, AlGaAs, GaN, InGaN, and AlGaInP. Say.

In recent years, thanks to the rapid development of semiconductor technology, light-emitting diodes have been released from low-intensity general-purpose products, enabling production of high-brightness and high-quality products. In addition, as the implementation of high-performance blue and white diodes becomes a reality, the application value of light emitting diodes is being extended to displays, next-generation lighting sources, and the like.

In particular, compound semiconductor light emitting devices using nitrides of group III-V have attracted attention because of their direct transition type with high probability of laser oscillation and the possibility of blue laser oscillation.

On the other hand, such a nitride-based semiconductor light emitting device is a pattern of a predetermined form is formed on the light emitting surface from which light is extracted in order to improve the efficiency of the light that can be extracted from it, that is, the external quantum efficiency.

Hereinafter, a vertical nitride based LED device among the nitride based LED devices according to the related art will be described in detail with reference to FIG. 1.

1 is a cross-sectional view showing the structure of a vertical nitride based LED device according to the prior art.

As shown in FIG. 1, a structural support layer 200 is formed at the bottom of the vertical nitride-based LED device according to the prior art. The structure support layer 200 may be formed of a Si substrate, a GaAs substrate, or a metal layer.

The p-type electrode 150 is formed on the structure support layer 200. The p-type electrode 150 is preferably made of a metal having a high reflectance so as to simultaneously serve as an electrode and a reflection role.

On the p-type electrode 150, a p-type nitride semiconductor layer 140, a GaN / InGaN active layer 130 having a multi quantum well type structure, and an n-type nitride semiconductor layer 120 are sequentially formed. .

An n-type electrode 160 is formed on the n-type nitride semiconductor layer 120.

In the vertical LED device, since light is emitted to the n-type nitride semiconductor layer 120, a pattern of a predetermined shape is formed on the top surface of the n-type nitride semiconductor layer 120 to improve light extraction efficiency. A transparent electrode 170 capable of improving current diffusion efficiency is formed on the n-type nitride semiconductor layer 120 having the pattern.

By the way, the surface pattern of the conventional nitride-based LED device is formed using any one of photo lithography, E-beam lithography and laser holography process. It was.

However, when the pattern is formed by using a photolithography process, it is difficult to realize the size of the pattern to be less than the nano (nano) size, even if implemented, there is a problem that expensive equipment must be provided.

In addition, when the pattern is formed by using an e-beam lithography process, there is also a problem in that expensive equipment is required to realize the size of the pattern to a nano size or less, and when using a laser holography process, the nano size or less. It can be implemented as, but there is a problem of low reproducibility and mass production.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide a nitride-based light emitting diode device that can improve the light extraction efficiency by forming a pattern of nano size or less on the light emitting surface without expensive equipment It is to provide a manufacturing method.

In order to achieve the above object, the present invention comprises the steps of sequentially forming an n-type nitride semiconductor layer, an active layer and a p-type nitride semiconductor layer on a substrate; Forming a p-type electrode on the p-type nitride semiconductor layer; Forming a structure support layer on the p-type electrode; Removing the substrate to expose a surface of the n-type nitride semiconductor layer; Forming a transparent conductive polymer layer on the exposed n-type nitride semiconductor layer; Pressing a stamp having a pattern of a predetermined shape onto the transparent conductive polymer layer to transfer the pattern onto the surface of the transparent conductive polymer layer; Curing the transparent conductive polymer layer to which the pattern is transferred; Separating the stamp from the cured transparent conductive polymer layer; It provides a method of manufacturing a nitride-based light emitting diode device comprising; and forming an n-type electrode on the transparent conductive polymer layer.

In the method of manufacturing the nitride-based light emitting diode device of the present invention, the transparent conductive polymer layer is selected from the group consisting of polyethylene dioxy thiophene (PEDOT), polypyrrole and polyaniline. It is preferable to form using any one selected.

In addition, to achieve the above object, the present invention comprises the steps of sequentially forming an n-type nitride semiconductor layer, an active layer and a p-type nitride semiconductor layer on a substrate; Mesa-etching a portion of the p-type nitride semiconductor layer and an active layer to expose a portion of the n-type nitride semiconductor layer; Forming a p-type electrode and an n-type electrode on the p-type nitride semiconductor layer and the exposed n-type nitride semiconductor layer, respectively; Forming a transparent polymer layer under the substrate; Pressing a stamp on which a pattern of a predetermined form is formed on the transparent polymer layer to transfer the pattern onto a surface of the transparent polymer layer; Curing the transparent polymer layer on which the pattern is transferred; And separating the stamp from the cured transparent polymer layer; provides a method of manufacturing a nitride-based light emitting diode device comprising a.

In addition, in the method of manufacturing the nitride-based light emitting diode device of the present invention, the transparent polymer layer is a polycarbonate, poly methyl methacrylate (poly methyl methacrylate), cyclo polyolefin (cyclopolyolefin), and unsaturated polyester It is preferable to form using any one selected from the group consisting of (unsaturated polyester).

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like reference numerals designate like parts throughout the specification.

Now, a method of manufacturing a nitride based light emitting diode device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First Embodiment

First, a method of manufacturing a nitride based LED device according to a first embodiment of the present invention will be described with reference to FIGS. 2A to 2F.

2A to 2F are cross-sectional views sequentially illustrating a method of manufacturing a nitride-based LED device according to a first embodiment of the present invention, illustrating a method of manufacturing a vertical nitride-based LED device.

First, as shown in FIG. 2A, an n-type nitride semiconductor layer 120, a GaN / InGaN active layer 130 having a multi-well structure, and a p-type nitride semiconductor layer 140 are sequentially stacked on the substrate 100. To form a light emitting structure.

In this case, the substrate 100 on which the light emitting structure is formed is preferably formed using a transparent material including sapphire, and in addition to sapphire, the substrate 100 is zinc oxide (ZnO), gallium nitride ( gallium nitride (GaN), silicon carbide (SiC) and aluminum nitride (AlN).

In addition, the n-type and p-type nitride semiconductor layers 120 and 140 and the active layer 130 are Al x In y Ga (1-xy) N composition formula (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y). Gallium nitride-based semiconductor material having a ≦ 1), and may be formed through a known nitride deposition process such as a MOCVD process.

More specifically, the n-type nitride semiconductor layer 120 may be formed of a GaN layer or a GaN / AlGaN layer doped with n-type conductive impurities, for example, Si, Ge, Sn And the like, and the p-type nitride semiconductor layer 140 may be formed of a GaN layer or a GaN / AlGaN layer doped with a p-type conductive impurity. Examples of the p-type conductive impurity may include Mg, Zn, Use Be.

Although not shown, a buffer layer may be further formed between the substrate 100 and the n-type nitride semiconductor layer 120 to improve lattice matching between the substrate 100 and the n-type nitride semiconductor layer 120. .

Next, as shown in FIG. 2B, the p-type electrode 150 is formed on the p-type nitride semiconductor layer 140. Then, the structural support layer 200 is formed on the p-type electrode 150.

Next, as shown in FIG. 2C, the substrate 100 is removed by an LLO process to expose the surface of the n-type nitride semiconductor layer 120.

Next, as shown in FIG. 2D, the transparent conductive polymer layer 170 is formed on the exposed n-type nitride semiconductor layer 120. The transparent conductive polymer layer 170 is preferably formed using any one selected from the group consisting of polyethylene dioxy thiophene (PEDOT), polypyrrole and polyaniline. In addition, the transparent conductive polymer layer 170 may be formed by spin coating, spray, or the like. The transparent conductive polymer layer 170 serves as a transparent electrode to improve current diffusion efficiency.

Here, in the embodiment of the present invention, a pattern of a predetermined shape is formed on the surface of the transparent conductive polymer layer 170 by using an imprint method.

The imprint method is a method invented by Stephen Chou et al. Of Princeton University in the United States to prepare the required shape on the surface of a relatively strong material in advance, and pattern it by stamping it on another material as if it were painted. After forming a mold of a desired shape, or by applying a polymer material into the mold to form a pattern. The imprint method has an advantage in that a fine pattern of nano size or less can be manufactured in large quantities, and the shape of the pattern can be freely implemented.

A method of forming a pattern on the transparent conductive polymer layer 170 using the imprint method is as follows.

First, as shown in FIG. 2D, a stamp 300 prepared in advance to have a desired predetermined pattern is provided on the transparent conductive polymer layer 170. The stamp 300 is preferably made of a high strength material, such as silicon, metal, diamond or quartz glass. In addition, the pattern size (d) of the stamp 300 preferably has a size of nano or less.

Next, as shown in FIG. 2E, the stamp 300 is pressed onto the transparent conductive polymer layer 170 to transfer the pattern onto the surface of the transparent conductive polymer layer 170. In addition, the transparent conductive polymer layer 170 to which the pattern is transferred is cured in a predetermined temperature range. The curing temperature may be made in a temperature range of about 80 ℃ to 100 ℃ depending on the type of the transparent conductive polymer layer 170.

Next, as shown in FIG. 2F, the stamp 300 is separated from the cured transparent conductive polymer layer 170. Accordingly, the pattern transferred to the surface of the transparent conductive polymer layer 170 also has the same size as the size (d) of the pattern formed on the stamp 300. That is, the size (d) of the pattern formed according to the present invention will have a size of nano or less.

Here, in order to prevent the transparent conductive polymer layer 170 from sticking to the surface of the stamp 300 when the stamp 300 is separated, the surface of the stamp 300 is subjected to a release treatment. desirable. At this time, the release treatment of the stamp 300 may be performed using a self assembly monolayer (SAM) technology, or through a C ₄ F ₈ coating method.

Then, the n-type electrode 160 is formed on the transparent conductive polymer layer 170.

As described above, the present invention is not limited to the size and shape of the pattern, and the nanoscale pattern is formed as in the prior art by forming the pattern on the light emitting surface of the device by an imprint method which is relatively simple in manufacturing process and cost competitive. It is possible to form a pattern of sub-nano size without having a separate expensive equipment for.

Accordingly, the present invention can provide a nitride-based LED device that can implement high brightness by improving the light extraction efficiency.

Second Embodiment

Hereinafter, a method of manufacturing a nitride based LED device according to a second embodiment of the present invention will be described with reference to FIGS. 3A to 3F.

3A to 3F are cross-sectional views sequentially illustrating a method of manufacturing a nitride based LED device according to a second exemplary embodiment of the present invention, and illustrate a method of manufacturing a horizontal nitride based LED device.

First, as shown in FIG. 3A, the buffer layer 110, the n-type nitride semiconductor layer 120, the active layer 130, and the p-type nitride semiconductor layer 140 are sequentially formed on the light transmissive substrate 100. do.

The substrate 100 is a substrate suitable for growing a nitride semiconductor single crystal, and is preferably formed using a transparent material including sapphire. In addition to sapphire, the substrate 100 may be formed of zinc oxide (ZnO), gallium nitride (GaN), silicon carbide (SiC), and aluminum nitride (AlN).

The buffer layer 110 is a layer for improving lattice matching with the substrate 100 before growing the n-type nitride semiconductor layer 120 on the substrate 100, and is omitted according to process conditions and device characteristics. It is possible.

The n-type and p-type nitride semiconductor layers 120 and 140 and the active layer 130 may have an Al _x In _y Ga _(1-x- y) N composition formula (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0). ≦ x + y ≦ 1) and may be formed through known nitride deposition processes such as MOCVD and MBE processes.

Next, as shown in FIG. 3B, a mesa etching for removing a portion of the p-type nitride semiconductor layer 140 and the active layer 130 to expose a portion of the n-type nitride semiconductor layer 120 ( mesa etching) process. This is to form a nitride-based semiconductor light emitting device having a horizontal structure of the nitride-based semiconductor light emitting device.

Then, as shown in FIG. 3C, the p-type electrode 150 and the n on the p-type nitride semiconductor layer 140 and the exposed n-type nitride semiconductor layer 120 which are not etched by the mesa etching process. The type electrodes 160 are formed, respectively.

Next, as shown in FIG. 3D, a transparent polymer layer 170 is formed under the substrate 100. Here, in the case of a horizontal LED, the transparent polymer layer formed at the lower portion of the substrate 100 ("170" in FIG. 3D) is the same as the transparent conductive polymer layer 170 of the vertical LED. Since it does not act as an electrode, it does not need to be a conductive polymer, but only a transparent polymer that can transmit light, such as polycarbonate, poly methyl methacrylate, and cyclo polyolefin. (cyclopolyolefin), and unsaturated polyester (unsaturated polyester) is preferably formed using any one selected from the group consisting of.

Next, a stamp 300 prepared in advance to have a desired predetermined pattern is provided below the transparent polymer layer 170. Pattern size (d) of the stamp 300 preferably has a size of nano or less.

Then, as shown in FIG. 3E, the stamp 300 is pressed onto the transparent polymer layer 170 to transfer the pattern onto the surface of the transparent polymer layer 170. In addition, the transparent polymer layer 170 on which the pattern is transferred is cured in a predetermined temperature range.

Next, as shown in FIG. 3F, the stamp 300 is separated from the cured transparent polymer layer 170. At this time, the pattern transferred to the surface of the transparent polymer layer 170 also has the same size as the size (d) of the pattern formed on the stamp (300). That is, the size (d) of the pattern formed according to the present invention will have a size of nano or less. The transparent polymer layer 170 on which the pattern is transferred reduces light loss lost in the substrate 100 to improve light extraction efficiency.

In the second embodiment of the present invention, as in the first embodiment, there is no restriction on the size and shape of the pattern, and the manufacturing process is relatively simple, and by applying a cost competitive imprint method, the nano-size of the conventional It is possible to form a pattern of sub-nano size without having a separate expensive equipment for forming a pattern.

Although the preferred embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the scope of the present invention is not limited to the disclosed embodiments, but various modifications and improvements of those skilled in the art using the basic concept of the present invention as defined in the following claims also belong to the scope of the present invention.

As described above, the present invention is not limited to the size and shape of the pattern, and the pattern is formed on the light emitting surface of the device through an imprint method, which is relatively simple in manufacturing process and competitive in cost, thereby improving the light extraction efficiency of the device. Can be improved.

Accordingly, the present invention can provide a nitride based light emitting diode device capable of realizing high brightness.

Claims (4)

Sequentially forming an n-type nitride semiconductor layer, an active layer, and a p-type nitride semiconductor layer on the substrate; Forming a p-type electrode on the p-type nitride semiconductor layer; Forming a structure support layer on the p-type electrode; Removing the substrate to expose a surface of the n-type nitride semiconductor layer; Forming a transparent conductive polymer layer on the exposed n-type nitride semiconductor layer; Pressing a stamp having a pattern of a predetermined shape onto the transparent conductive polymer layer to transfer the pattern onto the surface of the transparent conductive polymer layer; Curing the transparent conductive polymer layer to which the pattern is transferred; Separating the stamp from the cured transparent conductive polymer layer; And Forming an n-type electrode on the transparent conductive polymer layer; Method of manufacturing a nitride-based light emitting diode device comprising a. The method of claim 1, The transparent conductive polymer layer is formed of a nitride-based light emitting diode using any one selected from the group consisting of polyethylene dioxy thiophene (PEDOT), polypyrrole and polyaniline (polyaniline) Method of manufacturing the device. Sequentially forming an n-type nitride semiconductor layer, an active layer, and a p-type nitride semiconductor layer on the substrate; Mesa-etching a portion of the p-type nitride semiconductor layer and an active layer to expose a portion of the n-type nitride semiconductor layer; Forming a p-type electrode and an n-type electrode on the p-type nitride semiconductor layer and the exposed n-type nitride semiconductor layer, respectively; Forming a transparent polymer layer under the substrate; Pressing a stamp on which a pattern of a predetermined form is formed on the transparent polymer layer to transfer the pattern onto a surface of the transparent polymer layer; Curing the transparent polymer layer on which the pattern is transferred; And Separating the stamp from the cured transparent polymer layer; Method of manufacturing a nitride-based light emitting diode device comprising a. The method of claim 3, The transparent polymer layer is formed by using any one selected from the group consisting of polycarbonate, poly methyl methacrylate, cyclopolyolefin, and unsaturated polyester. A method of manufacturing a nitride-based light emitting diode device, characterized in that.

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