KR20060077807A - Light emitting diode formed by latteral growth and method for fabricating the same - Google Patents

Abstract

The present invention relates to a side-grown light emitting diode and a method of manufacturing the same. The process of forming a dielectric thin film pattern on a sapphire substrate is simpler than a process of etching a sapphire substrate, and thus the number of processes can be reduced. Lateral growth is possible, which has an excellent effect of reducing defects such as dislocations.

Total reflection, luminescence, dielectric, pattern, defect

Description

Side-grown light emitting diodes and method of manufacturing the same {Light emitting diode formed by latteral growth and method for fabricating the same}             

1 is a schematic cross-sectional view illustrating a phenomenon in which light is totally reflected in a light emitting diode according to the prior art.

2A and 2B are cross-sectional views illustrating a process of manufacturing a light emitting diode using a patterned sapphire substrate (PSS) according to the prior art.

3A to 3E are schematic cross-sectional views illustrating a method of manufacturing a nitride semiconductor light emitting diode according to the present invention.

4 is a schematic cross-sectional view illustrating a phenomenon in which light is refracted and emitted to the outside of the device in the light emitting diode according to the present invention.

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

100 substrate 110 dielectric thin film

111 dielectric thin film pattern 120 photoresist pattern

130: buffer layer 140: light emitting diode structure

The present invention relates to a side-grown light emitting diode and a method of manufacturing the same. More specifically, the step of forming a dielectric thin film pattern on a sapphire substrate is easier than the process of etching a conventional sapphire substrate to reduce the number of steps, the dielectric The present invention relates to a laterally grown light emitting diode capable of lateral growth using a thin film pattern and to reducing defects such as dislocations, and a method of manufacturing the same.

In recent years, optical devices using nitride compound semiconductors have been widely used in various fields.

In particular, laser diodes and light emitting diodes using these materials can be said to be essential for the development of a full color display board, a display such as a signal lamp, and the development of a high density optical recording medium.

FIG. 1 is a schematic cross-sectional view illustrating a phenomenon in which light is totally reflected in a light emitting diode according to the related art. In the case where the light emitting diode structure 20 is grown on the sapphire substrate 10, the light emitting diode structure 20 may be formed in the light emitting diode structure 20. When the generated light contacts the interface of the light emitting diode structure 20 and the flat sapphire substrate 10 in a path greater than or equal to the critical angle α, the generated light is totally reflected to be absorbed by the light emitting diode structure 20.

As such, the totally reflected light is not emitted to the outside of the device and is absorbed into the device, thereby degrading optical properties.                         

On the other hand, a gallium nitride-based optical device is an essential element to grow a high quality gallium nitride thin film to improve the optical properties.

However, in recent years, it has been seen to have a greater effect in the short term through a method of properly extracting the amount of light generated inside to the outside of the optical device than to improve the optical properties of the optical device by improving the crystallinity of the gallium nitride thin film.

One of the methods introduced for this purpose is a method using a patterned sapphire substrate (hereinafter referred to as 'PSS').

2A and 2B are cross-sectional views illustrating a process of manufacturing a light emitting diode using a patterned sapphire substrate (PSS) according to the prior art. As shown in FIG. 2A, the bending pattern 11 is formed on the sapphire substrate 10. 2B, the light emitting diode structure 20 is grown on the curved pattern 11 of the sapphire substrate 10.

In other words, the PSS method patterns a sapphire substrate before the gallium nitride is grown to make a specific shape of a bend, and then proceeds to grow gallium nitride on the curved shape, and extracts it from the planar light emitting diode to the outside by total reflection. The amount of light that could not be extracted can be extracted.

In this way, the internal light amount can be extracted to the outside by designing the LED structure to have a refractive index difference in the lateral direction.

However, the sapphire substrate has a problem that it is difficult to easily etch and control the thickness as desired by conventional RIE or the like.

In order to solve the above problems, the process of forming the dielectric thin film pattern on the sapphire substrate is easier than the process of etching the conventional sapphire substrate to reduce the number of processes, side growth using the dielectric thin film pattern It is an object of the present invention to provide a laterally grown light emitting diode capable of reducing defects such as dislocations and a method of manufacturing the same.

A preferred aspect for achieving the above object of the present invention is a substrate;

A dielectric pattern formed on the substrate;

A buffer layer laterally grown on the substrate and the dielectric pattern;

There is provided a side grown light emitting diode made of a light emitting diode structure formed on the buffer layer.

Another preferred aspect for achieving the object of the present invention comprises the steps of: forming a dielectric thin film on the substrate, and forming a photoresist pattern on the dielectric thin film;

Etching the dielectric thin film using the photoresist pattern as a mask to form a dielectric thin film pattern;

Laterally growing a buffer layer on the dielectric thin film pattern;

There is provided a method for manufacturing a side-grown light emitting diode consisting of growing a light emitting diode structure on the buffer layer.

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

3A to 3E are schematic cross-sectional views illustrating a method of manufacturing a nitride semiconductor light emitting diode according to the present invention. A dielectric thin film 110 is formed on a substrate 100 (FIG. 3A), and the dielectric thin film 110 is formed. ) A photoresist pattern 120 is formed on the top (FIG. 3B).

Here, the substrate 100 is preferably any one of sapphire (Sapphire), silicon carbide (Sic), ZnO, Si, GaAs and GaN.

In addition, the thickness T1 of the deposited dielectric thin film 110 is preferably 1 to 5㎛.

Next, the dielectric thin film 110 is etched using the photoresist pattern 120 as a mask to form the dielectric thin film pattern 111 (FIG. 3C).

In this case, the dielectric thin film pattern 111 is formed of a region in which the dielectric remains and a region in which the sapphire substrate is exposed by etching the dielectric.

The dielectric thin film pattern 111 may be any one of SiO ₂ , Si _x N _y, and SiON.

Subsequently, the buffer layer 130 is laterally grown on the dielectric thin film pattern 111 (FIG. 3D).

The buffer layer 130 may be formed of a thin film made of any one of GaN, Al _X Ga _(1-X) N (0 <X <1), and In _x Ga _(1-X) N (0 <X <1). It is preferable to form.

In addition, when the buffer layer 130 is GaN, one of Si, Zn, Mg, and In may be included.

The buffer layer 130 may have a thickness of about 1 μm to about 10 μm.

In this process, the buffer layer 130 is grown on the surface of the substrate 100 exposed by the dielectric thin film pattern 111, and laterally grown on the dielectric thin film pattern 111, and eventually, the laterally grown buffer layer is coalesced. And a flat buffer layer is grown.

Finally, the light emitting diode structure 140 is grown on the buffer layer 130 (FIG. 3E).

Here, the light emitting diode structure 140 is preferably made of a laminated film of films including GaN.

As described above, the process of forming the dielectric thin film pattern on the sapphire substrate is simpler than the process of etching the conventional sapphire substrate, so that the number of processes can be reduced, and the side growth using the dielectric thin film pattern is possible. This has the advantage of reducing the same defects.

4 is a schematic cross-sectional view for describing a phenomenon in which a light is refracted by the light emitting diode according to the present invention and is emitted to the outside of the device. In the present invention, a dielectric thin film pattern 111 is present on the substrate 100, thereby providing a light emitting diode. Light emitted from the structure 140 is refracted at the interface between the buffer layer 130 and the dielectric pattern 111 and at the interface between the dielectric pattern 111 and the substrate 100 to emit light to the outside.                     

That is, when the light of the light emitting diode structure 140 is incident on the sapphire substrate, due to the bending of the dielectric pattern 111 formed on the sapphire substrate, most of the light emitting diode structure 140 is less than the critical angle is emitted to the outside without total reflection, thereby improving the light output It becomes possible.

As such, the manufactured light emitting diode may include a sapphire substrate 100, as shown in FIG. 4; A dielectric pattern 111 formed on the sapphire substrate 100; A buffer layer 130 formed on the sapphire substrate 100 and the dielectric pattern 111; The light emitting diode structure 140 is formed on the buffer layer 130.

As described above, in the present invention, the process of forming the dielectric thin film pattern on the sapphire substrate is simpler than the process of etching the conventional sapphire substrate, so that the number of processes can be reduced, and the side growth using the dielectric thin film pattern is possible. It has an excellent effect of reducing defects such as dislocations.

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 (6)

A substrate; A dielectric pattern formed on the substrate; A buffer layer laterally grown on the substrate and the dielectric pattern; A side-grown light emitting diode comprising a light emitting diode structure formed on the buffer layer. The method of claim 1, The dielectric pattern is, A side grown light emitting diode, which is any one of SiO ₂ , Si _x N _y and SiON. The method of claim 1, The buffer layer, Lateral growth, characterized in that the thin film is made of any one of GaN, Al _X Ga _(1-X) N (0 <X <1) and In _x Ga _(1-X) N (0 <X <1) Light emitting diode. The method of claim 1, The thickness of the dielectric pattern, 1 to 5 μm, The thickness of the buffer layer, Side-grown light emitting diodes, characterized in that 1 ~ 10㎛. The method according to any one of claims 1 to 4, The light emitting diode structure, A side grown light emitting diode comprising a stacked film of GaN-containing films. Forming a dielectric thin film on the substrate and forming a photoresist pattern on the dielectric thin film; Etching the dielectric thin film using the photoresist pattern as a mask to form a dielectric thin film pattern; Laterally growing a buffer layer on the dielectric thin film pattern; Growing a light emitting diode structure on the buffer layer.

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