KR100673641B1 - Vertically structured gan type light emitting diode device and method of manufacturing the same - Google Patents

Abstract

A vertical GaN based light emitting diode device and a manufacturing method thereof are provided to improve a photo-efficiency by forming additionally a reflective layer on at least one side of a structure support layer. A vertical GaN based light emitting diode device includes an N type contact pad(210), a light emissive structure under the N type contact pad, a P type electrode(270) under the light emissive structure, a structure support layer(280) under the P type electrode, and a reflective layer. The light emissive structure is composed of an N type GaN layer(240), an active layer(250) and a P type GaN layer(260). The reflective layer(300) is formed on at least one surface of the structure support layer.

Description

Vertically structured GaN type light emitting diode device and method of manufacturing the same

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

2 and 3 are cross-sectional views showing the structure of a vertical gallium nitride-based LED device according to an embodiment of the present invention.

Figures 4a to 4e is a cross-sectional view for each process for explaining the manufacturing method of the vertical structure gallium nitride based LED device according to an embodiment of the present invention.

<Description of the reference numerals for the main parts of the drawings>

200: sapphire substrate 210: n-type contact pad

220: n-type reflective electrode 230: n-type transparent electrode

240: n-type GaN layer 250: active layer

260: p-type GaN layer 270: p-type electrode

280: structural support layer 300: reflective film

310: shield

The present invention relates to a vertical structure (vertical electrode type) gallium nitride-based (GaN) light emitting diode (hereinafter referred to as "LED") device and a method of manufacturing the same, more specifically, LED chip is finally packaged The present invention relates to a vertically structured gallium nitride-based LED device and a method for manufacturing the same, which can enhance light emission efficiency to the outside of the package in the state of being made.

In general, gallium nitride-based LEDs grow on sapphire substrates, but these sapphire substrates are hard, electrically nonconducting, and have poor thermal conductivity, reducing the size of gallium nitride-based LEDs, thereby reducing manufacturing costs, or improving light output and chip characteristics. There is a limit to this. In particular, it is important to solve the heat dissipation problem of the LED because a large current is required for the high output of the LED.

As a means for solving this problem, a vertical gallium nitride-based LED device has been proposed in which a sapphire substrate is removed by using a laser lift-off (LLO; hereinafter referred to as 'LLO').

Next, a vertical gallium nitride based LED element according to the prior art will be described in detail with reference to FIG. 1.

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

As shown in FIG. 1, a structural support layer 180 is formed at the bottom of a vertical gallium nitride based LED device according to the prior art, which serves as a support layer and an electrode of the LED device. The structure support layer 180 is preferably formed using any one of a Si substrate, a GaAs substrate, and a metal layer.

The plating seed layer (not shown) and the p-type electrode 170 are sequentially formed on the structure support layer 180. Here, the p-type electrode 170 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 170, a p-type GaN layer 160, a GaN / InGaN active layer 150 having a multi quantum well type structure, and an n-type GaN layer 140 are sequentially formed.

On the n-type GaN layer 140, an n-type transparent electrode 130 for improving the current spreading phenomenon, and an n-type reflective electrode 120 for improving the light efficiency are sequentially formed. In this case, the n-type transparent electrode 130 and the n-type reflective electrode 120 may not be formed.

An n-type contact pad 110 is formed on the n-type reflective electrode 120.

However, in the vertical structure gallium nitride-based LED device according to the prior art as described above, using the Si substrate, the GaAs substrate, the metal layer, and the like as the structural support layer 180, the junction with the p-type electrode 170 and the like. However, this is only a structure designed mainly in consideration of thermal stability and process stability of the structural support layer 180 and the junction, the structure support layer 180 has a low reflection characteristics. Therefore, when the LED chip including the structural support layer 180 is finally packaged, a photon generated by the chip and not reflected directly inside the package, but reflected inside, has a low reflection characteristic at the side of the structural support layer 180. Due to the disappearance, there is a problem that the light emission efficiency to the outside of the package is reduced.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention, a vertical structure gallium nitride-based light emitting diode device that can increase the light emission efficiency to the outside of the package in the state that the LED chip is finally packaged and its It is to provide a manufacturing method.

Vertical structure gallium nitride-based light emitting diode device according to the present invention for achieving the above object,

n-type contact pads;

A light emitting structure in which an n-type GaN layer, an active layer, and a p-type GaN layer are sequentially formed below the n-type contact pad;

A p-type electrode formed under the light emitting structure;

A structural support layer formed under the p-type electrode; And

It includes a reflective film formed on at least one surface of the structural support layer.

Here, the reflective film is characterized in that formed on the side, or side and bottom of the structural support layer.

The reflective film is made of any one or two or more alloys of Al, Ag, Cr, Pd, Pt, Co, Hf, Ti, Ni, and W.

In addition, it characterized in that it further comprises a protective film formed on the reflective film.

The protective film may be any one selected from the group consisting of SiO ₂ , TiO ₂ , Al ₂ O ₃ , SnO ₂ , In ₂ O ₃ , ITO, IZO, ZrO ₃ , YAG, Y ₂ O _3, and Si _x N _y . It is characterized by consisting of one.

In addition, the manufacturing method of the vertical structure gallium nitride-based light emitting diode device according to the present invention for achieving the above object,

Sequentially forming an n-type GaN layer, an active layer, and a p-type GaN layer on the sapphire substrate;

Forming a p-type electrode on the p-type GaN layer;

Forming a structure support layer on the p-type electrode;

Removing the sapphire substrate by an LLO process;

Forming an n-type contact pad on the n-type GaN layer from which the sapphire substrate is removed; And

Forming a reflective film on at least one surface of the structure support layer.

Here, the reflective film is formed on the side, or side and bottom of the structure support layer.

The reflective film is any one selected from the group consisting of sputtering, evaporator, chemical vapor deposition (CVD), electroplating, non-plating, and laser ablation. It is characterized by forming in a method.

In addition, after the forming of the reflective film,

Forming a protective film on the reflective film is characterized in that it further comprises.

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

Embodiment of the structure of the vertical structure gallium nitride-based LED device

Referring to Figures 2 and 3 will be described in detail with respect to the vertical structure gallium nitride-based LED device according to an embodiment of the present invention.

2 and 3 are cross-sectional views showing the structure of the vertical structure gallium nitride-based LED device according to an embodiment of the present invention.

First, as shown in FIG. 2, a structural support layer 280 is formed at the bottom of the vertical gallium nitride based LED device according to an exemplary embodiment of the present invention to serve as a support layer and an electrode of the LED device. The structure support layer 280 is preferably formed using any one of a Si substrate, a GaAs substrate, and a metal layer.

The reflective film 300 is formed on at least one surface of the structural support layer 280. The reflective film 300 may be made of any one or any two or more alloys of Al, Ag, Cr, Pd, Pt, Co, Hf, Ti, Ni, and W, and is formed on the side of the structural support layer 280. It is preferable.

Although not shown in the drawing, the reflective film 300 may be further formed on the lower surface of the structural support layer 280 as well as the side surface of the structural support layer 280.

As described above, in the present embodiment, when the LED chip including the reflective film 300 is finally packaged by additionally forming the reflective film 300 on the side, or the side, and the bottom surface of the structural support layer 280, the chip Photons that are generated at and are not reflected out to the outside but are reflected by the reflective film 300 formed on the surface of the structural support layer 280 may improve light emission efficiency to the outside of the package. .

At this time, a protective film 310 may be further formed on the reflective film 300 as shown in FIG. 3. The protective layer 310 may include SiO ₂ , TiO ₂ , Al ₂ O ₃ , SnO ₂ , In ₂ O ₃ , ITO, IZO, ZrO ₃ , YAG, Y in consideration of reflection characteristics and oxidation prevention of the reflective film 300. It is preferable to form using oxides, nitrides and the like such as ₂ O ₃ and Si _x N _y .

On the structure support layer 280, a plating seed layer (not shown) and a p-type electrode 270 are sequentially formed. Here, the p-type electrode 270 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 270, a p-type GaN layer 260, a GaN / InGaN active layer 250 having a multi quantum well type structure, and an n-type GaN layer 240 are sequentially formed.

On the n-type GaN layer 240, an n-type transparent electrode 230 for improving a current spreading phenomenon and an n-type reflective electrode 220 for improving light efficiency are sequentially formed. In this case, the n-type transparent electrode 230 and the n-type reflective electrode 220 may not be formed.

An n-type contact pad 210 is formed on the n-type reflective electrode 220.

Embodiment of the manufacturing method of the vertical structure gallium nitride-based LED device

Hereinafter, a method of manufacturing a vertical gallium nitride based LED device according to an embodiment of the present invention as described above will be described.

4A through 4E are cross-sectional views of processes for describing a method of manufacturing a vertical gallium nitride based LED device according to an exemplary embodiment of the present invention.

As shown in FIG. 4A, the n-type GaN layer 240, the active layer 250, and the p-type GaN layer 260 are sequentially grown on the sapphire substrate 200 to form a light emitting structure. Among the light emitting structures, the n-type GaN layer 240 may be formed of an n-type impurity doped GaN layer or a GaN / AlGaN layer, and the active layer 250 may be an InGaN / GaN layer. Well) structure, and the p-type GaN layer 260 may be formed of a GaN layer or a GaN / AlGaN layer doped with p-type impurities like the n-type GaN layer 240.

Next, a p-type electrode 270 is formed on the light emitting structure. The p-type electrode 270 may be made of a metal having high reflectance to simultaneously serve as an electrode and a reflection role.

Next, after forming a plating seed layer (not shown) on the p-type electrode 270, the structural support layer 280 is sequentially formed on the plating seed layer by electrolytic plating or electroless plating. . The plating seed layer serves as a plating crystal nucleus in a plating process for forming the structure support layer 280, and the structure support layer 280 serves as a support layer and an electrode of the final LED device. .

Meanwhile, in the present exemplary embodiment, the plating layer formed by using the plating seed layer as the crystal nucleus as the structure supporting layer 280 is described, but the present invention is not limited thereto, and the structure supporting layer 207 is the final LED as described above. As a support layer and an electrode of the device, the device may be formed of a silicon (Si) substrate, a GaAs substrate, a Ge substrate, or a metal layer.

As shown in FIG. 4B, the sapphire substrate 200 is removed by an LLO process.

As shown in FIG. 4C, on the n-type GaN layer 240 from which the sapphire substrate 200 is removed, an n-type transparent electrode 230 for improving current spreading phenomenon, and n for improving light efficiency. The type reflective electrode 220 is sequentially formed. In this case, the process of forming the n-type transparent electrode 230 and the n-type reflective electrode 220 may be omitted.

Next, an n-type contact pad 210 is formed on the n-type reflective electrode 220.

As shown in FIG. 4D, the reflective film 300 is formed on at least one surface of the structure support layer 280. The reflective film 300 may be formed of any one or two or more alloys of a material having high reflectance, such as Al, Ag, Cr, Pd, Pt, Co, Hf, Ti, Ni, and W, which is the structural support layer. It is preferably formed on the side of 280.

Although not shown in the drawings, the reflective film 300 may be further formed on the lower surface of the structural support layer 280 as well as the side surface of the structural support layer 280. The reflective film 300 may be formed by a general thin film deposition method such as sputter, evaporator, CVD, electroplating, electroless plating, and laser ablation. The reflective film 300 may be deposited and used simultaneously on all surfaces of the structural support layer 280 including the side surface of the structural support layer 280.

According to an embodiment of the present invention, when the LED chip including the reflective film 300 is finally packaged by additionally forming the reflective film 300 on the side or all surfaces of the structural support layer 280, the chip The photons that are generated in and are not reflected directly to the outside but are reflected inside are reflected by the reflective film 300, thereby improving light emission efficiency to the outside of the package.

As shown in FIG. 4E, the protective film 310 is formed on the reflective film 300 in consideration of the oxidation prevention and reflection characteristics of the reflective film 300. The protective film 310 may be formed of an oxide or nitride such as SiO ₂ , TiO ₂ , Al ₂ O ₃ , SnO ₂ , In ₂ O ₃ , ITO, IZO, ZrO ₃ , YAG, Y ₂ O _3, and Si _x N _y . It is preferable to form using. Here, when the reflective film 300 is formed not only on the side surface of the structure support layer 280 but also on the lower surface, that is, on all surfaces of the structure support layer 280, as described above, the protective film 310 also has the structure support layer ( It may be formed on the reflective film 300 formed on all surfaces of the 280.

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 thereto, and 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 fall within the scope of the present invention.

As described above, the present invention further forms a reflective film, or a reflective film and a protective film on at least one surface of the structural support layer, so that when the LED chip including the reflective film is finally packaged, it is not generated from the chip and immediately exits to the outside. Photons reflected therein may be prevented from disappearing from the surface of the structural support layer, and may be reflected by a reflective film formed on the structural support layer. Therefore, the present invention has the effect of improving the light emission efficiency to the outside of the package.

Claims (9)

n-type contact pads; A light emitting structure in which an n-type GaN layer, an active layer, and a p-type GaN layer are sequentially formed below the n-type contact pad; A p-type electrode formed under the light emitting structure; A structural support layer formed under the p-type electrode; And And a gallium nitride-based light emitting diode device including a reflective film formed on at least one surface of the structure support layer. The method of claim 1, The reflective film is a vertical structure gallium nitride-based light emitting diode device, characterized in that formed on the side, or side and bottom of the structure support layer. The method of claim 1, The reflective film is a gallium nitride-based light emitting diode device, characterized in that made of any one or any two or more alloys of Al, Ag, Cr, Pd, Pt, Co, Hf, Ti, Ni and W. The method of claim 1, The gallium nitride-based light emitting diode device characterized in that it further comprises a protective film formed on the reflective film. The method of claim 4, wherein The protective film is made of any one selected from the group consisting of SiO ₂ , TiO ₂ , Al ₂ O ₃ , SnO ₂ , In ₂ O ₃ , ITO, IZO, ZrO ₃ , YAG, Y ₂ O ₃ and Si _x N _y . A vertical structure gallium nitride-based light emitting diode device, characterized in that. Sequentially forming an n-type GaN layer, an active layer, and a p-type GaN layer on the sapphire substrate; Forming a p-type electrode on the p-type GaN layer; Forming a structure support layer on the p-type electrode; Removing the sapphire substrate by an LLO process; Forming an n-type contact pad on the n-type GaN layer from which the sapphire substrate is removed; And And forming a reflective film on at least one surface of the structural support layer. The method of claim 6, The reflective film is formed on the side, or side and bottom of the structure support layer, the method of manufacturing a vertical gallium nitride-based light emitting diode device. The method of claim 6, The reflective film is any one selected from the group consisting of sputter, evaporator, chemical vapor deposition (CVD), electroplating, non-plating, and laser ablation. A method of manufacturing a vertical gallium nitride-based light emitting diode device characterized in that it is formed. The method of claim 6, After the forming of the reflective film, The method of manufacturing a vertical gallium nitride-based light emitting diode device characterized in that it further comprises the step of forming a protective film on the reflective film.

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