KR20030072762A - Semiconductor light emitting diode and method for manufacturing the same - Google Patents

Abstract

PURPOSE: A semiconductor light emitting diode and a method for manufacturing the same are provided to be capable of easily forming quantum dots in an active layer by using a luminance reinforce layer. CONSTITUTION: An n-GaN layer(51), an n-AlGaN layer(52), an active layer(80), a p-AlGaN layer(53) and a p-GaN layer(54) are sequentially formed on a substrate(50). The stacked structure is etched to form mesa structure. An n-electrode(57) is formed on the etched n-GaN layer, and a transparent electrode(55) and a p-electrode(56) are formed on the p-GaN layer. At the time, the active layer(80) has repeatedly and sequentially stacked structure of a luminance reinforce layer(81,84,87), a well layer(82,85,88) and a barrier layer(83,86,89).

Description

Semiconductor light emitting diode and method for manufacturing the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting diode and a method of manufacturing the same, and more particularly, to forming a brightness reinforcing layer before growing a well layer, thereby facilitating the formation of quantum dots in the active layer, thereby increasing the light emitting efficiency of the light emitting diode. A light emitting diode and a method of manufacturing the same.

Recently, with the development of light emitting diodes and laser diode manufacturing techniques using III-V nitride semiconductor materials, light emitting devices such as ultraviolet light, blue, green, and blue violet laser diodes have been developed and commercialized.

However, in order to actually apply such light emitting devices to various fields, it is necessary to realize high efficiency and high brightness.

In particular, in the field of ultraviolet light emitting diodes in which intensive research is being conducted in order to replace fluorescent lamps and incandescent bulbs used for general lighting, the biggest problem is to greatly improve luminance.

It is important how high-brightness light emitting diodes and laser diodes grow quantum well structures composed of InGaN.

However, in order to obtain a high quality InGaN layer, InGaN having a relatively high Indium mole fraction is obtained at a high temperature because a high growth temperature is required but the vapor pressure of InN is high. Is not easy.

In addition, since there is an immiscibility gap between GaN and InN, that is, a mixture in which only 6% of In is uniformly distributed in GaN is formed at 800 ° C., and in other conditions, it is nonuniform between GaN and InN. Since a mixture is formed, it can be said that it is difficult to grow InGaN having a higher quality and higher indium content ratio.

Therefore, there is a considerable influence on the characteristics of the InGaN layer depending on the equipment and growth conditions used.

1 is a cross-sectional view of a general semiconductor laser diode, in which an nGaN layer 21, an nAlGaN layer 22, an active layer 23, a pAlGaN layer 24, and a pGaN layer 25 are sequentially formed on the semiconductor wafer 20. The semiconductor laser diode was implemented by stacking.

Of course, the n-electrode is formed on the bottom surface of the semiconductor wafer 20, the p-electrode is formed on the pGaN layer 25, and the laser light is emitted from the active layer 23 by applying a current.

However, such a light emitting device is important for the brightness performance of the light, in order to improve this, various structures have been tried.

For example, an n-type AlGaN 22 is formed between the nGaN layer 21 and the active layer 23 shown in FIG. 1, and a p-type AlGaN 24 is formed between the active layer 23 and the pGaN layer 25. Therefore, a method of increasing the recombination efficiency of electrons and holes by restricting electrons and holes efficiently in the active layer is widely used.

On the other hand, since light emission is known to occur strongly in quantum dots locally formed in the active layer, a method for generating a lot of such quantum dots is a key to improving luminance.

2 is a cross-sectional view of a basic structure of an active layer of a nitride-based light emitting diode, in which an n-gallium nitride layer 11 is grown on an upper portion of the substrate 10 and an n-gallium nitride layer 11 on an active layer ( 30 is formed, and a p-gallium nitride layer 22 is formed on the active layer 30.

The active layer 30 includes the first well layer 12, the first barrier layer 13, the second well layer 14, the second barrier layer 15,. The n barrier layer 17 is sequentially laminated.

Here, it has been announced that the formation of quantum dots is easy by depositing a thin layer of silicon or indium prior to well growth to form quantum dots.

However, in the case of silicon, it is reported that not only there are many differences in the effect of silicon doping on the light emitting device according to the growth conditions, but also, when more than one silicon doping is exceeded, it may reduce local quantum dot formation.

In the case of indium, the atomic size is larger than that of gallium, which may cause a piezoelectric phenomenon, which may cause wavelength change, and also because indium has a high vapor pressure at high temperature, it is not easy to deposit a desired amount, thus obtaining a good crystalline film. Is difficult.

Accordingly, the present invention has been made to solve the problems described above, in order to improve the luminous efficiency of the active layer when fabricating a light emitting diode using a III-V nitride system, before the growth of the active layer of silicon or indium It is an object of the present invention to provide a semiconductor light emitting diode capable of forming a quantum dot having high luminous efficiency in the active layer by pre-depositing aluminum (Aluminum) before the active layer growth to escape the deposition method in advance, and a method of manufacturing the same.

According to a preferred aspect of the present invention, an n-gallium nitride layer, an n-AlGaN layer, an active layer, a p-AlGaN layer, and a p-gallium nitride layer are sequentially formed on an upper portion of a substrate. There is;

Mesa etching from the p-gallium nitride layer to a part of the n-gallium nitride layer, an n-electrode is formed on the etched n-gallium nitride layer;

A transparent electrode and a p-electrode are sequentially formed on the p-gallium nitride layer;

The active layer is provided with a semiconductor light emitting diode in which a luminance enhancement layer, a well layer and a barrier layer are successively stacked alternately.

Another preferred aspect for achieving the above object of the present invention is a method for manufacturing a semiconductor light emitting diode comprising an active layer in which a well layer and a barrier layer are continuously stacked alternately,

Before the well layer is grown, a method of manufacturing a semiconductor light emitting diode is provided in which any one selected from an aluminum mono layer, an Al + Si alloy layer, an Al + In alloy layer, and an Al + Si + In alloy layer is grown.

1 is a cross-sectional view of a general semiconductor laser diode.

2 is a cross-sectional view of a basic structure of an active layer of a general nitride based light emitting diode.

3 is a diagram illustrating that each source is used according to time when the active layer is grown.

4 is a cross-sectional view showing in detail one well stacked structure of a nitride light emitting diode according to the present invention.

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

50 substrate 51 n-gallium nitride layer

52: n-AlGaN layer 53: p-AlGaN layer

54 p-gallium nitride layer 55 transparent electrode

56 p-electrode 57 n-electrode

81,84,87: luminance enhancement layer 82,85,88: well layer

83,86,89: barrier layer

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

FIG. 3 is a diagram illustrating that each source is used according to time when the active layer is grown, and the luminance reinforcing layer is grown in an ammonia (NH ₃ ) and aluminum atmosphere before the well layer is grown, and then ammonia, gallium (Ga) and indium are grown. The well layer and the barrier layer are grown in the atmosphere of (In).

Here, the luminance reinforcing layer is supplied to the aluminum 2 to 100 sccm at 700 ~ 1000 ℃, 1-10 aluminum monolayers (mono layer is a layer in which molecules are uniformly arranged only two-dimensional plane, 2 monolayers, in which two monolayers are stacked).

In the pre-deposited aluminum, Ga and In are grown when the well layer is grown, thereby easily forming quantum dots, and exhibiting excellent luminous efficiency when manufacturing a light emitting diode.

In addition, when aluminum and silicon and indium are simultaneously deposited to form an Al + Si alloy layer, an Al + In alloy layer and an Al + Si + In alloy layer before growth of the well layer, the formation of quantum dots becomes easier, resulting in a high luminance light emitting diode. It becomes possible to manufacture.

Here, too, the amount of Si and In supplied to be deposited is 2 sccm to 95 sccm, and the Al + Si alloy layer and the Al + In alloy layer before the well layer is grown at 1-10 monolayers at a temperature of 700-1000 ° C. An Al + Si + In alloy layer is formed.

4 is a cross-sectional view showing in detail one well stacked structure of a nitride light emitting diode according to the present invention. The n-gallium nitride layer 51, the n-AlGaN layer 52, and the active layer 80), the p-AlGaN layer 53 and the p-gallium nitride layer 54 are sequentially formed, and the mesa (Mesa) from the p-gallium nitride layer 54 to a part of the n-gallium nitride layer 51 After being etched, an n-electrode 57 is formed on the etched n-gallium nitride layer 51.

In addition, the transparent electrode 55 and the p-electrode 56 are sequentially formed on the p-gallium nitride layer 54.

In the present invention, before the well layer is grown, the structure of the active layer is selected by growing an aluminum mono layer, an Al + Si alloy layer, an Al + In alloy layer, and an Al + Si + In alloy layer, thereby smoothly forming quantum dots. can do.

Accordingly, as shown in FIG. 4, the active layer 80 may be formed of a first luminance enhancement layer 81, a first well layer 82, a first barrier layer 83, a second luminance enhancement layer 84, and a second well layer ( 85), the second barrier layer 86, ..., the n-th luminance enhancement layer 87, the n-th well layer 88 and the n-th barrier layer 89 facilitate the formation of quantum dots.

In this case, the luminance reinforcing layer is any one selected from the aluminum mono layer, Al + Si alloy layer, Al + In alloy layer and Al + Si + In alloy layer.

The luminance reinforcing layer is preferably configured by depositing a monolayer in which each molecule is horizontally arranged in one molecule thickness in a range of 1 to 10.

As described above in detail, the present invention has the effect of increasing the luminous efficiency of the light emitting diode by facilitating the formation of quantum dots in the active layer by forming the luminance reinforcing layer before growing the well layer.

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 (4)

An n-gallium nitride layer, an n-AlGaN layer, an active layer, a p-AlGaN layer and a p-gallium nitride layer are sequentially formed on the substrate; Mesa etching from the p-gallium nitride layer to a part of the n-gallium nitride layer, an n-electrode is formed on the etched n-gallium nitride layer; A transparent electrode and a p-electrode are sequentially formed on the p-gallium nitride layer; The active layer is a semiconductor light emitting diode, characterized in that the luminance reinforcing layer, the well layer and the barrier layer are continuously stacked alternately. The method of claim 1, The brightness enhancement layer is a semiconductor light emitting diode, characterized in that any one selected from aluminum mono layer, Al + Si alloy layer, Al + In alloy layer and Al + Si + In alloy layer. The method of claim 2, The brightness enhancement layer is a semiconductor light emitting diode, characterized in that the molecules are laminated in the range of 1 to 10 in a mono-layer unit uniformly arranged only two-dimensional plane. In the manufacturing method of the semiconductor light emitting diode provided with the active layer by which the well layer and the barrier layer were successively laminated alternately, Before the well layer is grown, a method of manufacturing a semiconductor light emitting diode, characterized in that any one selected from aluminum mono layer, Al + Si alloy layer, Al + In alloy layer and Al + Si + In alloy layer.