KR100858362B1 - Method for forming vertically structured light emitting diode device - Google Patents

Abstract

A method for forming a vertically structured LED device is provided to improve a yield by forming a buffer layer between a light emitting structure and a structure supporting layer. A sapphire substrate is prepared. A light emitting structure(120) including an n type gallium nitride-based semiconductor layer(121), an active layer(122), and a p type gallium nitride-based semiconductor layer(123) is formed on the sapphire substrate. A p type electrode(150) is formed on the p type gallium nitride-based semiconductor layer. A buffer layer is formed on the p type electrode. A structure supporting layer(170) is formed on the buffer layer. The n type gallium nitride-based semiconductor layer is exposed by removing the sapphire substrate. An n type electrode is formed on the exposed n type gallium nitride-based semiconductor layer. The buffer layer is formed by using the gallium nitride-based semiconductor, the structure supporting layer, and a metal having a grating constant of 1 percent and less.

Description

Method for manufacturing vertically structured light emitting diode device {Method for forming vertically structured Light Emitting Diode device}

The present invention relates to a vertical structure (vertical electrode type) light emitting diode (hereinafter, referred to as "LED") device, and more particularly, to the vertical structure that can prevent damage to the light emitting structure during the structure support layer forming process A method of manufacturing a structured LED device.

In general, LED devices grow on sapphire substrates, but these sapphire substrates are hard, electrically nonconducting, and have poor thermal conductivity, making them difficult to reduce the size of LED devices to reduce manufacturing costs, or to improve light output and chip characteristics. there was. In particular, in order to increase the output power of the LED device is required to apply a large current, it is important to solve the heat dissipation problem of the LED device.

As a means to solve this problem, a vertical structure LED device has been proposed in which a sapphire substrate is removed using a laser lift-off (LLO) technique.

Next, a method of manufacturing a conventional vertical structure LED device will be described in detail with reference to FIGS. 1A to 1E.

1A through 1E are cross-sectional views sequentially illustrating a method of manufacturing a vertical LED device according to the prior art.

First, as shown in FIG. 1A, a light emitting structure 120 made of a gallium nitride based semiconductor layer is formed on a sapphire substrate 110. In this case, the light emitting structure 120 has a structure in which the n-type gallium nitride-based semiconductor layer 121, the multi-well GaN / InGaN active layer 122, and the p-type gallium nitride-based semiconductor layer 123 are sequentially stacked. Have

Subsequently, as illustrated in FIG. 1B, a p-type electrode 150 is formed on the p-type gallium nitride based semiconductor layer 123. In this case, the p-type electrode 150 serves as an electrode and a reflective film.

Next, as shown in FIG. 1C, after forming an adhesive layer 160 for attaching a structural support layer on the p-type electrode 150 by eutectic bonding, a predetermined temperature is formed on the adhesive layer 160. The bonding process of bonding the structural support layer 170 on the adhesive layer 160 is applied by applying a pressure and a pressure. In this case, the structural support layer 170 serves as a supporting layer and an electrode of the final LED element, and mainly uses a silicon substrate.

Thereafter, as shown in FIG. 1D, the sapphire substrate 110 is removed through an LLO process.

Subsequently, as shown in FIG. 1E, an n-type electrode 180 is formed on the n-type gallium nitride based semiconductor layer 121 exposed separately from the sapphire substrate (not shown).

However, the bonding process of bonding the structural support layer 170 according to the prior art as described above, because the bonding layer 160 is bonded at a high pressure at a high temperature of 200 ℃ to 300 ℃ using a metal such as Au, the bonded When the resultant is cooled to room temperature, physical stresses such as stresses due to different lattice constants and thermal expansion coefficients of the structural support layer 170 and the light emitting structure 120 are generated, and in severe cases, the light emitting structure 120 is damaged. there is a problem.

An object of the present invention, in order to solve the above problems, in the structure support layer forming process and the laser lift-off process for removing the sapphire substrate, the manufacturing method of the vertical structure gallium nitride-based LED device that can prevent damage to the light emitting structure To provide.

In order to achieve the above object, the present invention is to prepare a sapphire substrate, and to form a light emitting structure formed by sequentially stacking an n-type gallium nitride-based semiconductor layer, an active layer and a p-type gallium nitride-based semiconductor layer on the sapphire substrate Forming a p-type electrode on the p-type gallium nitride-based semiconductor layer, forming a buffer layer on the p-type electrode, forming a structure support layer on the buffer layer, and sapphire Removing the substrate to expose an n-type gallium nitride-based semiconductor layer and forming an n-type electrode on the exposed n-type gallium nitride-based semiconductor layer, wherein the buffer layer comprises a gallium nitride-based constituting the light emitting structure. It provides a method of manufacturing a vertical structure LED device, characterized in that formed using a semiconductor and a metal having a lattice constant difference of less than 1%.

In addition, in the manufacturing method of the vertical structure LED device of the present invention, the buffer layer is preferably formed of ZrB ₂ .

In addition, in the manufacturing method of the vertical structure LED device of the present invention, it is preferable to further include forming an adhesive layer on the buffer layer before the step of forming a structure support layer on the buffer layer.

In addition, in the manufacturing method of the vertical structure LED device of the present invention, it is preferable that the structure supporting layer is formed by using a wafer bonding method or electroplating using an electrically conductive material.

In addition, in the manufacturing method of the vertical structure LED device of the present invention, the p-type electrode is preferably formed of at least one layer selected from the ohmic layer, the reflective film and the barrier layer.

The present invention has a buffer layer formed of a material having a pseudo lattice constant therebetween between the light emitting structure and the structure support layer, and when bonding the light emitting structure and the structure support layer, and then bonded at a high temperature / high pressure, and then cooling the bonded result to room temperature, It is possible to prevent a problem that the light emitting structure is damaged by different lattice constants and thermal expansion coefficients of the light emitting structure and the structure support layer.

Therefore, the present invention can improve the manufacturing yield of the vertical structure LED device.

Detailed technical configuration of the manufacturing method of the vertical structure LED device of the present invention will be clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of 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.

Example

Hereinafter, a method of manufacturing a vertical structure LED device according to an embodiment of the present invention will be described in detail with reference to FIGS. 2A to 2F.

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

First, as shown in FIG. 2A, a light emitting structure 120 made of a gallium nitride based semiconductor layer is formed on the sapphire substrate 110. In this case, the light emitting structure 120 has a structure in which the n-type gallium nitride-based semiconductor layer 121, the multi-well GaN / InGaN active layer 122 and the p-type gallium nitride-based semiconductor layer 123 are sequentially stacked Have

Herein, the p-type and n-type gallium nitride based semiconductor layers 121 and 123 and the active layer 122 may have an Al x In y Ga (1-xy) N composition formula, where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, and 0 ≦ x. gallium nitride-based semiconductor material having + y ≦ 1) and may be formed through known nitride deposition processes such as MOCVD and MBE processes.

On the other hand, the active layer 130 may be formed of one quantum well layer or a double hetero structure.

Subsequently, as shown in FIG. 2B, a p-type electrode 150 is formed on the p-type gallium nitride based semiconductor layer 123. In this case, the p-type electrode 150 may be formed to simultaneously serve as an electrode and a reflective film. Accordingly, the p-type electrode 150 may be formed of at least one selected from an ohmic layer, a reflective film, and a barrier layer.

Next, as shown in FIG. 2C, a buffer layer 200 is formed on the p-type electrode 150. In this case, the buffer layer 200 serves to buffer the physical stress caused by the difference in the lattice constant and thermal expansion coefficient of the structure support layer forming process to be described later, the light emitting structure 120 and the structure support layer to be described later It is preferable to form using a metal having a lattice constant difference of 1% or less, and accordingly, in the present embodiment, ZrB ₂ is formed.

Subsequently, as shown in FIG. 2D, an adhesive layer 160 is formed on the buffer layer 200 to attach the structural support layer by eutectic bonding. Then, the adhesive layer 160 is subjected to high temperature / high pressure. A bonding process of bonding the structural support layer 170 on the adhesive layer 160 is performed. In this case, since the structural support layer 170 preferably serves as a supporting layer and an electrode of the final LED device, a material having good thermal conductivity and conductivity, such as a silicon (Si) substrate, a GaAs substrate, a Ge substrate, or It is formed using a metal layer or the like.

In addition, the bonding layer 160 may be formed using gold (Au) or an alloy including gold (for example, AuSn).

Meanwhile, in the present embodiment, the wafer bonding method using the adhesive layer 160 as a method of forming the structure support layer 170 is described. However, the present invention is not limited thereto, and the structure support layer is a support layer and an electrode of the final LED device. As a role to serve as, it can be formed by an electroplating method using a plating nucleus layer.

Subsequently, as shown in FIG. 2E, the substrate 110 is removed through the LLO process to expose the surface of the n-type gallium nitride based semiconductor layer 121.

Then, as illustrated in FIG. 2F, the n-type electrode 180 is formed on the n-type gallium nitride based semiconductor layer 121 exposed by removing the sapphire substrate (not shown).

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.

1A to 1E are cross-sectional views sequentially illustrating a method of manufacturing a vertical LED device according to the prior art.

2A to 2F are cross-sectional views sequentially illustrating a method of manufacturing a vertical structure LED device according to an exemplary embodiment of the present invention.

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

110: sapphire substrate 120: light emitting structure

121 n-type nitride semiconductor layer 122 active layer

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

160: adhesive layer 170: structural support layer

180: n-type electrode

Claims (6)

Preparing a sapphire substrate; Forming a light emitting structure formed by sequentially stacking an n-type gallium nitride-based semiconductor layer, an active layer, and a p-type gallium nitride-based semiconductor layer on the sapphire substrate; Forming a p-type electrode on the p-type gallium nitride based semiconductor layer; Forming a buffer layer on the p-type electrode; Forming a structure support layer on the buffer layer; Removing the sapphire substrate to expose an n-type gallium nitride based semiconductor layer; And And forming an n-type electrode on the exposed n-type gallium nitride based semiconductor layer. The buffer layer is a manufacturing method of a vertical structure LED device, characterized in that formed using a gallium nitride-based semiconductor constituting the light emitting structure and a metal having a lattice constant difference between the structure supporting layer and 1% or less. The method of claim 1, The buffer layer is a manufacturing method of a vertical structure LED device, characterized in that formed by ZrB ₂ . The method of claim 1, And forming an adhesive layer on the buffer layer before forming the structure support layer on the buffer layer. The method of claim 1, The structure supporting layer is a method of manufacturing a vertical structure LED device, characterized in that formed using an electrically conductive material. The method of claim 1, The structure supporting layer is a method of manufacturing a vertical structure LED device, characterized in that formed using a wafer bonding method or an electroplating method. The method of claim 1, The p-type electrode is a method of manufacturing a vertical structure LED device, characterized in that formed of at least one layer selected from the ohmic layer, reflective film and barrier layer.

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