KR20030065884A - Light emitting diode and method for manufacturing the same - Google Patents

Abstract

PURPOSE: An LED and its manufacturing method are provided to emit high brightness light with no transparent metal for current diffusion in a defect region by using a GaN substrate grown by a SAG method(selective area growth). CONSTITUTION: A nGaN layer(16), an active layer(17), and pGaN layer(18) are sequentially deposited on a GaN substrate grown by SAG. A portion of the nGaN layer is exposed by vertical mesa etching of the pGaN, the active layer and the nGaN layer. A transparent metal(25) for current diffusion is deposited on the pGaN layer.

Description

Light emitting diode and method for manufacturing the same

The present invention relates to a light emitting diode and a method of manufacturing the same, and more particularly, using a gallium nitride substrate grown by a selective area growth (SAG) method, to form a current diffusion transparent metal in the defective region The present invention relates to a light emitting diode capable of emitting high luminance light and a method of manufacturing the same.

Recently, blue and green light emitting diodes using gallium nitride have been developed with the development of group III nitride growth technology and are widely used.

In the blue and green light emitting diodes using gallium nitride, there is an increasing demand for emitting high luminance light, and the development thereof is urgently required.

In order for the light emitting diode to emit high luminance light, the gallium nitride layer forming the diode must not contain defects.

By the way, the light emitting diode is manufactured by growing a gallium nitride layer on the sapphire (Al ₂ O ₃ ) or silicon carbide (SiC) substrate, the lattice mismatch between the substrate and the grown gallium nitride layer As a result, defects such as dislocations occur, which hinders the implementation of the high brightness light emitting diodes.

Therefore, researches for reducing the potential of the gallium nitride layer have been conducted in various ways. In one method, a high quality gallium nitride substrate is produced, and a light emitting diode is manufactured from the gallium nitride substrate, thereby eliminating the occurrence of defects. There is a method of implementing a light emitting diode of brightness.

Such high-quality gallium nitride substrates are grown using hydride vapor phase epitaxy (HVPE) or defects in selective regions using selective area growth (SAG). Gallium nitride substrates were grown.

1A to 1C show a process of manufacturing a gallium nitride substrate by a general selective region growth method. First, a gallium nitride layer 13 and a silicon oxide film 11 are sequentially grown on an sapphire substrate 10 (FIG. 1A). Some surfaces of the silicon oxide film 11 are removed to form the surfaces 13a, 13b, and 13c on which the gallium nitride layer 13 is exposed (FIG. 1B).

Next, when the gallium nitride layer is grown on the upper surface of the silicon oxide film 11 and the exposed surface of the gallium nitride layer 13 by the lateral growth method, the surface 13a, on which the gallium nitride layer 13 is exposed, A defect 14 was generated in the gallium nitride layer 13 grown on 13b and 13c, and no defect was generated in the gallium nitride layer grown on the silicon oxide film 11.

There are various methods of manufacturing a gallium nitride substrate by the selective region growth method, and it has been commercialized by being applied to a device having a small area of an active region such as a laser diode.

In addition, gallium nitride substrates produced by the hydride vapor phase epitaxial growth method described above have not yet been commercialized.

FIG. 2 is a cross-sectional view of a light emitting diode fabricated using a gallium nitride substrate grown by a general selective region growth method, wherein an nGaN layer 16 and an active layer 17 are formed on the gallium nitride substrate 12 grown by a selective region growth method. ) And pGaN layer 18 are sequentially stacked, and the pGaN layer 16, the active layer 17 and the nGaN layer 18 are mesa-etched to expose a portion of the nGaN layer 16. Let's do it.

Subsequently, a thin film of current diffusion transparent metal (T / M) 19 such as thin Ni / Au is deposited on the pGaN layer 18, and a p electrode (on the top of the transparent metal 19) is deposited. 20) and the n-electrode 21 formed on the nGaN layer 16 exposed by the mesa etching to form a light emitting diode.

In the light emitting diode manufactured as described above, defects generated in the substrate manufactured by the selective region growth method are propagated to the nGaN layer 16, the active layer 17, and the pGaN layer 18 so that the defects 28 exist in the light emitting region. It will contain the region.

Therefore, the light emitted from the active layer in the low quality region is lower than the light emitted from the active layer in the relatively high quality region, and as a result, there is a problem that the brightness of the light emitted from the light emitting diode is lowered.

Accordingly, the present invention has been made to solve the above problems, using a gallium nitride substrate grown by the selective region growth method, do not form a transparent metal for current diffusion in the defective region, the light of high brightness An object of the present invention is to provide a light emitting diode capable of emitting light and a method of manufacturing the same.

According to a preferred aspect of the present invention, an nGaN layer, an active layer, and a pGaN layer are sequentially stacked on a gallium nitride substrate grown by a selective region growth method;

The pGaN layer, the active layer and the nGaN layer are mesa-etched in a vertical direction to expose a portion of the nGaN layer;

A current diffusion transparent metal is formed on the pGaN layer except for a region having a defect propagated from the gallium nitride substrate grown by the selective region growth method;

An n-electrode is formed on the nGaN layer, and a p-electrode is provided so that a p-electrode is formed on the transparent metal for current diffusion.

Another preferred aspect for achieving the above object of the present invention comprises the steps of: sequentially depositing an nGaN layer, an active layer and a pGaN layer on top of the gallium nitride substrate grown by the selective region growth method;

Exposing a portion of the nGaN layer by mesa etching the pGaN layer, the active layer and the nGaN layer in a vertical direction;

Forming a transparent metal for current diffusion except for a region having a defect propagated from the gallium nitride substrate grown by the selective region growth method on the pGaN layer;

A method of manufacturing a light emitting diode is provided, which includes forming an n electrode on the nGaN layer and forming a p electrode on the current diffusion transparent metal.

1A to 1C are process charts for manufacturing a gallium nitride substrate by a general selective region growth method.

2 is a cross-sectional view of a light emitting diode manufactured using a gallium nitride substrate grown by a general selective region growth method.

3 is a process chart for manufacturing a light emitting diode using a gallium nitride substrate grown by the selective region growth method according to the present invention.

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4 is a top view of a light emitting diode manufactured using a gallium nitride substrate grown by a selective region growth method according to the present invention.

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

12: gallium nitride substrate grown by selective region growth method

16: nGaN layer 17: active layer

18: pGaN layer 25: transparent metal for current diffusion

26a, 26b, 26c, and 26d: defected region 30: p electrode

31: n electrode

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

3 is a process diagram for manufacturing a light emitting diode using a gallium nitride substrate grown by the selective region growth method according to the present invention, the nGaN layer 16 on the gallium nitride substrate 12 grown by the selective region growth method In addition, the active layer 17 and the pGaN layer 18 are sequentially stacked, and the pGaN layer 16, the active layer 17, and the nGaN layer 18 are mesa-etched in a vertical direction to form the nGaN layer 16. A portion of the layer is exposed and a current spreading transparent metal (T / M) 25 such as thin Ni / Au is deposited on top of the pGaN layer 18 (FIG. 3A).

Surfaces exposing the pGaN layer 18 by removing the transparent metal 25 in the region having the defect 28 propagated from the gallium nitride substrate 12 grown by the selective region growth method by a conventional photolithography method. (26a, 26b, 26c, 26d) are formed (FIG. 3B).

4 is a top view of a light emitting diode manufactured using a gallium nitride substrate grown by a selective region growth method according to the present invention, wherein a transparent metal 25 for current diffusion is formed on the top surface of the light emitting diode. The current diffusion transparent metal 25 is formed on the upper surface of the light emitting diode except for the defective areas 26a, 26b, 26c, and 26d of the light emitting diode.

The p-electrode 30 is formed on the upper surface of the current diffusion transparent metal 25, and the n-electrode 31 is formed on the nGaN layer 16 exposed by the mesa etching.

Therefore, the present invention uses a gallium nitride substrate grown by the selective region growth method, and does not form a current diffusion transparent metal in the defective region, thereby supplying current only to the region where the defect does not exist, thereby providing high luminance light. A light emitting diode capable of emitting light can be implemented.

As described in detail above, the present invention does not form a transparent metal for current diffusion in a defective region by using a gallium nitride substrate grown by a selective region growth method, and thus has the effect of emitting high luminance light. .

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 (3)

An nGaN layer, an active layer and a pGaN layer are sequentially stacked on the gallium nitride substrate grown by the selective area growth (SAG) method; The pGaN layer, the active layer and the nGaN layer are mesa-etched in a vertical direction to expose a portion of the nGaN layer; A current diffusion transparent metal is formed on the pGaN layer except for a region having a defect propagated from the gallium nitride substrate grown by the selective region growth method; An n electrode is formed on the nGaN layer, and a p electrode is formed on the transparent metal for current diffusion. The method of claim 1, The current diffusion transparent metal is a light emitting diode, characterized in that Ni / Au. Sequentially stacking an nGaN layer, an active layer and a pGaN layer on top of the gallium nitride substrate grown by the selective region growth method; Exposing a portion of the nGaN layer by mesa etching the pGaN layer, the active layer and the nGaN layer in a vertical direction; Forming a transparent metal for current diffusion except for a region having a defect propagated from the gallium nitride substrate grown by the selective region growth method on the pGaN layer; Forming an n electrode on the nGaN layer and forming a p electrode on the transparent metal for current diffusion.