KR20150078089A - Nitride semiconductor light emitting device with v-pit and method of manufacturing the same - Google Patents

Abstract

Disclosed is a method for manufacturing a nitride semiconductor light emitting device with a v-pit. A nitride semiconductor light emitting device according to the present invention includes an n-type nitride semiconductor layer; an active layer which is formed on the -type nitride semiconductor layer and has a surface with a v-pit; a p-side intermediate layer which is formed on the active layer and has a flat surface; an electron shielding layer which is formed on the p-side intermediate layer and has a flat surface; and a p-type nitride semiconductor layer which is formed on the electron shielding layer.

Description

TECHNICAL FIELD [0001] The present invention relates to a nitride semiconductor light emitting device having a v-pit and a method of manufacturing the same. [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitride semiconductor light emitting device manufacturing technology, and more particularly, to a nitride semiconductor light emitting device having a v-pit and a manufacturing method thereof.

The nitride semiconductor light emitting device has a structure in which an active layer is formed between an n-type nitride semiconductor layer doped with an n-type impurity such as silicon and a p-type nitride semiconductor layer doped with a p-type impurity such as magnesium. In the case of such a nitride semiconductor light emitting device, electrons supplied from the n-type nitride semiconductor layer and holes supplied from the p-type nitride semiconductor layer recombine in the active layer to generate light.

On the other hand, it is known that the light extraction efficiency can be improved when the nitride semiconductor light emitting device is formed in a v-pit structure.

FIG. 1 schematically shows a part of a conventional nitride semiconductor light emitting device having a v-pit.

Referring to FIG. 1, a structure in which an active layer 120 and an electron blocking layer 130 are sequentially formed on an n-type nitride semiconductor layer 110 having an initial v-pit on a surface thereof, . The initial v-pit may be formed through growth temperature control or chemical etching of the n-type nitride semiconductor layer 110. A p-type nitride semiconductor layer (not shown) is formed on the electron blocking layer 130, and the surface of the p-type nitride semiconductor layer is generally planarized.

The electron blocking layer 130 is generally formed of p-AlGaN or p-InAlGaN. Further, the electron blocking layer is grown to have the same structure as the v-pit inclined plane as in the example shown in Fig. The reason for this is that, in the case of the electron blocking layer, the electron blocking layer needs to be relatively thin to the order of several tens nm, so that the holes supplied from the p-type nitride semiconductor layer can be smoothly transported to the active layer. For this reason, in the case of the conventional nitride semiconductor light emitting device having a v-pit, the electron blocking layer formed to be thin and having the v-pit structure becomes a leakage current path due to the potential, .

As a background art related to the present invention, there is disclosed a method of manufacturing a nitride semiconductor light emitting device having a v-pit disclosed in Korean Patent Laid-Open Publication No. 10-2010-0093872 (published on Aug. 26, 2010).

An object of the present invention is to provide a nitride semiconductor light emitting device having a structure including a v-pit and having a reverse voltage characteristic and a method of manufacturing the same.

According to an aspect of the present invention, there is provided a nitride semiconductor light emitting device including: an n-type nitride semiconductor layer; An active layer formed on the n-type nitride semiconductor layer and having a surface on which a plurality of v-pits are formed; A p-side intermediate layer formed on the active layer and having a flat surface; An electron blocking layer formed on the p-side intermediate layer and having a flat surface; And a p-type nitride semiconductor layer formed on the electron blocking layer.

At this time, the p-side intermediate layer may be formed of a p-type nitride semiconductor or a non-doped nitride semiconductor.

The p-side intermediate layer is preferably formed to a thickness of 3 to 2000 nm.

Further, the nitride semiconductor light emitting device may further include an n-side intermediate layer formed between the n-type nitride semiconductor layer and the active layer and having an initial v-pit formed surface. In this case, the n-side intermediate layer may be formed of InGaN having an indium concentration of 6 atomic% or less of the entire Group III element, a superlattice structure, or GaN. The n-side intermediate layer preferably has a thickness of 0.1 to 2 탆.

According to an aspect of the present invention, there is provided a method of fabricating a nitride semiconductor light emitting device, comprising: forming an n-type nitride semiconductor layer on a substrate; Forming an n-side intermediate layer having a surface on which an initial v-pit is formed on the n-type nitride semiconductor layer; Forming an active layer having a surface on which a plurality of v-pits are formed, on the n-side intermediate layer; Forming a p-side intermediate layer having a flat surface on the active layer; Forming an electron blocking layer having a flat surface on the p-side intermediate layer; And forming a p-type nitride semiconductor layer on the electron blocking layer.

At this time, the p-side intermediate layer may be formed in an atmosphere containing at least one of hydrogen and nitrogen. Also, the electron blocking layer and the p-type nitride semiconductor layer may be formed in a hydrogen atmosphere, and the active layer may be formed in a nitrogen atmosphere.

The p-side intermediate layer may be formed of a p-type nitride semiconductor or a non-doped nitride semiconductor.

The p-side intermediate layer may be formed to a thickness of 3 to 2000 nm.

Further, the method may further include forming an n-side intermediate layer between the n-type nitride semiconductor layer and the active layer, the n-side intermediate layer having a surface on which the initial v-pit is formed. In this case, the n-side intermediate layer may be formed of InGaN having a indium concentration of 6 atomic% or less of the entire Group III element, superlattice structure, or GaN. The n-side intermediate layer is preferably formed at a temperature of 700 to 1000 ° C. The n-side intermediate layer preferably has a thickness of 0.1 to 2 탆.

According to the method of manufacturing a nitride semiconductor light emitting device according to the present invention, a p-side intermediate layer is formed without forming an electron blocking layer directly on an active layer having a surface on which v-pits are formed, resulting in merging of v- The surface of the intermediate layer on the side of the intermediate layer can be planarized, and thus the electron blocking layer can also be formed flat, so that a nitride semiconductor light emitting device having an excellent reverse voltage characteristic can be manufactured.

FIG. 1 shows a part of a conventional nitride semiconductor light emitting device having a v-pit.
2 shows a part of a nitride semiconductor light emitting device having a v-pit according to an embodiment of the present invention.
FIG. 3 schematically shows a nitride semiconductor light emitting device including the p-side intermediate layer shown in FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish them, will become apparent by reference to the embodiments described in detail below with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Hereinafter, a method of fabricating a nitride semiconductor light emitting device having a v-pit according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 shows a part of a nitride semiconductor light emitting device having a v-pit according to an embodiment of the present invention, and FIG. 3 is a schematic view of a nitride semiconductor light emitting device including a p-side intermediate layer shown in FIG.

2 and 3, a nitride semiconductor light emitting device having a v-pit according to the present invention includes an n-type nitride semiconductor layer 110, an active layer 120, a p-side intermediate layer 210, And a p-type nitride semiconductor layer 140. Each of the nitride semiconductor layers may be formed on a growth substrate 101 such as a sapphire substrate. For the purpose of improving crystal quality and the like before the formation of the n-type nitride semiconductor layer, an undoped nitride semiconductor layer 102, .

The n-type nitride semiconductor layer 110 may be formed of a nitride semiconductor doped with an n-type impurity such as Si. The active layer 120 may be formed of, for example, a multiple quantum well (MQW) structure in which GaN quantum barrier layers and InGaN quantum well layers are alternately stacked. The electron blocking layer 130 may be formed of AlGaN or InAlGaN doped with a p-type impurity such as Mg. The p-type nitride semiconductor layer 140 may be formed of a nitride semiconductor doped with a p-type impurity such as Mg.

In the case of the present invention, the active layer 120 is formed in a shape having a plurality of v-pit formed surfaces. As described above, when the electron blocking layer is formed directly on the active layer 120, the inclination of the v-pit is formed as shown in Fig. In this case, there is a problem that the electron blocking layer becomes a leakage current path due to the potential and the reverse voltage characteristic is deteriorated.

The inventors of the present invention have found that when the intermediate layer capable of merging the v-pits is formed before forming the electron blocking layer, the electron blocking layer can be planarized, Improved. Hereinafter, an intermediate layer formed between the active layer 120 and the electron blocking layer 130 is referred to as a p-side intermediate layer 210.

When the p-side intermediate layer 210 is formed, its surface has a flat surface. As a result, the electron blocking layer 130 formed on the p-side intermediate layer 210 may have a flat surface.

At this time, the p-side intermediate layer 210 may be formed of a p-type nitride semiconductor or an undoped nitride semiconductor.

The p-side intermediate layer 210 is preferably formed to a thickness of 3 nm to 2000 nm. When the thickness of the p-side intermediate layer is formed to a thickness of less than 3 nm, the v-pitting effect is insufficient. Conversely, when the thickness of the p-side intermediate layer exceeds 2000 nm, the possibility of electron-hole recombination in the p-side intermediate layer 210 may increase.

2 and 3, the nitride semiconductor light emitting device according to the present invention is formed between an n-type nitride semiconductor layer 110 and an active layer 120, and includes an n-side intermediate layer having an initial v- (230).

The n-side intermediate layer 230 may be formed of InGaN having a indium concentration of 6 atomic% or less of the entire Group 3 element, a superlattice structure, or GaN. When the growth temperature is controlled to 700 to 1000 ° C, An initial v-pit may be formed. At this time, it is preferable that the n-side intermediate layer has a thickness of 0.1 to 2 탆. When the thickness of the n-side intermediate layer is less than 0.1 占 퐉, formation of v-pits is almost impossible. When the thickness of the n-side intermediate layer exceeds 2 占 퐉, excessive growth of v- And the luminous efficiency can be reduced.

Hereinafter, a method for manufacturing a nitride semiconductor light emitting device having a v-pit according to the present invention will be described.

First, on the substrate 101, an n-type nitride semiconductor layer 110 is formed. various functional layers such as an undoped nitride semiconductor layer 102, a current blocking layer, and a buffer layer may be formed before the formation of the n-type nitride semiconductor layer.

Thereafter, an n-side intermediate layer 230 having a surface on which an initial v-pit is formed is formed on the n-type nitride semiconductor layer. As described above, the n-side intermediate layer 230 may be formed of InGaN having an indium concentration of 6 atomic% or less, a superlattice structure, or GaN of the entire Group 3 element. In this case, the n-side intermediate layer 230 is preferably formed to a thickness of 0.1 to 2 占 퐉 at 700 to 1000 占 폚. When the growth temperature of the n-side intermediate layer 230 is less than 700 캜, the crystal quality may be largely lowered. When the growth temperature exceeds 1000 캜, the initial v-pits formed may be insufficient. When the thickness of the n-side intermediate layer is less than 0.1 탆, the possibility of forming the initial v-pit is low, and when the thickness of the n-side intermediate layer exceeds 2 탆, the initial v-pit is excessively grown, The surface can be excessively reduced.

Next, on the n-side intermediate layer 230, the active layer 120 having a surface having a plurality of v-pits is formed. The active layer 120 is formed on a flat surface between the initial v-pit slope and the initial v-pit. The active layer 120 may be formed in a nitrogen atmosphere.

Next, a p-side intermediate layer 210 is formed on the active layer 120 to form a flat surface. The p-side intermediate layer 210 may be formed of a p-type nitride semiconductor or an undoped nitride semiconductor, and may be formed to a thickness of 3 to 2000 nm.

In the case of the p-side intermediate layer 210, it may be formed in any atmosphere of a nitrogen atmosphere and a hydrogen atmosphere.

Next, an electron blocking layer 130 having a flat surface is formed on the p-side intermediate layer 210. Then, a p-type nitride semiconductor layer 140 is formed on the electron blocking layer 130.

The electron blocking layer and the p-type nitride semiconductor layer may be formed in a hydrogen atmosphere.

Table 1 shows a nitride semiconductor light emitting device (comparative example) in which a p-AlGaN electron blocking layer was formed to a thickness of 50 nm on an active layer having a surface with a v-pit formed thereon, and a p-GaN And the p-AlGaN electron blocking layer was formed to a thickness of 50 nm after forming the p-AlGaN electron blocking layer (Example). In the case of each of the nitride semiconductor light emitting devices of Comparative Examples and Examples, the same conditions were applied except for the above conditions.

The reverse voltage drop (Vr (V)) was measured at 10uA for the evaluation of the reverse voltage characteristics, and the results are shown in Table 1.

[Table 1]

Referring to Table 1, it can be seen that, in comparison with the comparative example, the embodiment exhibits excellent reverse voltage characteristics.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. These changes and modifications may be made without departing from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims.

101: substrate
102: An undoped nitride semiconductor layer
110: an n-type nitride semiconductor layer
120: active layer
130: electron blocking layer
140: a p-type nitride semiconductor layer
210: p-side middle layer
230: n-side middle layer

Claims (14)

an n-type nitride semiconductor layer;
An active layer formed on the n-type nitride semiconductor layer and having a surface on which a plurality of v-pits are formed;
A p-side intermediate layer formed on the active layer and having a flat surface;
An electron blocking layer formed on the p-side intermediate layer and having a flat surface; And
And a p-type nitride semiconductor layer formed on the electron blocking layer.
The method according to claim 1,
And the p-side intermediate layer is formed of a p-type nitride semiconductor or an undoped nitride semiconductor.
The method according to claim 1,
And the p-side intermediate layer is formed to a thickness of 3 nm to 2000 nm.
The method according to claim 1,
And an n-side intermediate layer formed between the n-type nitride semiconductor layer and the active layer and having an initial v-pit formed surface.
5. The method of claim 4,
And the n-side intermediate layer is formed of InGaN, a super lattice structure or GaN having an indium concentration of 6 atomic% or less of the entire Group III element in the n-side intermediate layer.
6. The method of claim 5,
And the n-side intermediate layer has a thickness of 0.1 to 2 占 퐉.
A method for manufacturing a semiconductor device, comprising: forming an n-type nitride semiconductor layer on a substrate;
Forming an n-side intermediate layer having a surface on which an initial v-pit is formed on the n-type nitride semiconductor layer;
Forming an active layer having a surface on which a plurality of v-pits are formed, on the n-side intermediate layer;
Forming a p-side intermediate layer having a flat surface on the active layer;
Forming an electron blocking layer having a flat surface on the p-side intermediate layer; And
And forming a p-type nitride semiconductor layer on the electron blocking layer.
8. The method of claim 7,
Wherein the p-side intermediate layer is formed in an atmosphere containing at least one of hydrogen and nitrogen.
9. The method of claim 8,
The electron blocking layer and the p-type nitride semiconductor layer are formed in a hydrogen atmosphere,
Wherein the active layer is formed in a nitrogen atmosphere.
8. The method of claim 7,
Wherein the p-side intermediate layer is formed of a p-type nitride semiconductor or an undoped nitride semiconductor.
8. The method of claim 7,
Wherein the p-side intermediate layer is formed to a thickness of 3 to 2000 nm.
8. The method of claim 7,
Wherein the n-side intermediate layer is formed of InGaN having a indium concentration of 6 atomic% or less, a superlattice structure, or GaN of the total of Group III elements.
13. The method of claim 12,
And the n-side intermediate layer is formed at 700 to 1000 ° C.
13. The method of claim 12,
Wherein the n-side intermediate layer has a thickness of 0.1 to 2 占 퐉.

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