KR20130120591A - Nitride semiconductor light emitting device and method for fabricating the same - Google Patents

Abstract

Disclosed are a nitride semiconductor light emitting device and a method for fabricating the same. The nitride semiconductor light emitting device of the present invention comprises: an N-type semiconductor layer and a P-type semiconductor layer; an active layer of a multi-quantum well structure, which is interposed between the N-type semiconductor layer and the P-type semiconductor layer, and has a plurality of quantum well layers and a plurality of quantum barrier layers that alternate with each other, wherein the active layer includes a first group and a second group, the first group made up of quantum well layers and quantum barrier layers that are formed in a region close to the N-type semiconductor layer and the P-type semiconductor layer, the second group made up of quantum well layers and quantum barrier layers that are formed in an inner region between the N-type semiconductor layer and the P-type semiconductor layer, and thicknesses of the quantum well layers and quantum barrier layers in the first group are greater than those of the quantum well layers and quantum barrier layers in the second group. In the present invention, the quantum barrier layers and quantum well layers are designed to have various thicknesses and a uniform light emitting waveform at the same time, whereby efficiency of light emission of the nitride semiconductor light emitting device is improved. In addition, film crystallization and electrical characteristics of the active layer are improved, thereby improving electron and hole mobility and current spreading from the N-type semiconductor layer and the P-type semiconductor layer to the active layer.

Description

Nitride semiconductor light emitting device and method of manufacturing the same {Nitride semiconductor light emitting device and method for fabricating the same}

The present invention relates to a nitride semiconductor light emitting device, and more particularly to a nitride semiconductor light emitting device having improved luminous efficiency and electrical characteristics.

In general, nitrides of Group III elements such as gallium nitride (GaN) and aluminum nitride (AlN) used in nitride semiconductor light emitting devices have excellent thermal stability and have a direct transition type energy band structure. It is attracting much attention as a material for optoelectronic devices in the ultraviolet region. In particular, blue and green light emitting devices using gallium nitride (GaN) have been used in various applications such as large-scale color flat panel displays, traffic lights, indoor lighting, high-density light sources, high resolution output systems and optical communication.

1 illustrates a structure of a conventional nitride semiconductor light emitting device, and FIG. 2 illustrates an active layer region of the multi-quantum well structure of FIG. 1, and FIG. 3 illustrates quantum efficiency of an active layer of a nitride semiconductor light emitting device. One drawing.

1 and 2, in the conventional nitride semiconductor light emitting device, a buffer layer 20 is formed on an insulating substrate 10, and an undoped semiconductor layer 21 and an N-type semiconductor layer are formed on the buffer layer 20. (22), the active layer 50, the P-type semiconductor layer 24, and the transparent metal layer 25 are laminated. The N-type electrode 27 and the P-type electrode 26 are formed on the N-type semiconductor layer 22 and the P-type semiconductor layer 24 exposed to the outside, respectively.

The insulating substrate 10 may be made of a material suitable for growing a nitride semiconductor single crystal. For example, the insulating substrate 10 may be formed using a material such as sapphire, and in addition to sapphire, zinc oxide (ZnO), gallium nitride (GaN), silicon carbide (silicon carbide) SiC), aluminum nitride (AlN), or the like.

The active layer 50 is a region where electrons and holes are recombined, and a plurality of quantum well layers 51 and quantum barrier layers 52 represented by a general formula of InxGa1-xN (0 ≦ x ≦ 1) are alternately formed. It has a quantum well structure. The emission wavelength emitted from the nitride semiconductor light emitting device is determined according to the kind of material constituting the active layer 50.

The active layer 50 has a single quantum well (SQW) structure having one quantum well layer and a multi quantum well (MQW) structure having a plurality of quantum well layers. Among them, as shown in FIG. 2, the active layer 50 of the multi-quantum well structure has better light efficiency compared to the current and has a high luminous output compared to the single quantum well structure.

The light efficiency of the nitride semiconductor light emitting device is basically determined by the probability of recombination of electrons and holes in the active layer, that is, internal quantum efficiency. In order to improve the internal quantum efficiency, research has been conducted mainly to improve the structure of the active layer itself or to increase the effective mass of the carrier.

However, in the multi-quantum well structure of the conventional nitride semiconductor device, as shown in FIG. 3, electrons provided from the N-type semiconductor layer 22 do not recombine with holes in the active layer 50 region as the current increases. Flow) is a problem that occurs. As shown in the figure, the probability of recombination of electrons and holes is high at low currents, and most electrons combine with holes to have high quantum efficiency characteristics, but as the current increases, the unbonded electrons increase and the quantum efficiency drops rapidly. You can see that. This lowers the light efficiency of the nitride semiconductor element.

In addition, due to the low growth temperature of the quantum well layer in the active layer, crystallinity is lowered, and due to non-radiative recombination in the active layer, the luminous recombination efficiency inside the active layer 50 is lowered, thereby lowering the internal quantum efficiency, In the case of a lateral chip, when electrons are transferred from the N-type electrode 27 to the active layer 50, electrons are not dispersed properly, resulting in electron overflow.

In addition, the active layer formed of the nitride semiconductor layers is polarized by the piezo electric field and is formed to be inclined differently from other bandgaps, which is used to perform the quantum confined stark effect (QCSE). By the quantum confinement effect, the recombination rate of electrons and holes decreases, resulting in low luminous efficiency. In addition, there is a problem that the external quantum efficiency is significantly reduced (Efficiency droop) tends to be applied when a high current is applied, which is called a droop phenomenon.

Conventionally, in order to solve this problem, a current spreading layer is formed between the N-type semiconductor layer 22 and the active layer 50 to improve light efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to provide a nitride semiconductor light emitting device having a thick quantum well layer and a quantum barrier layer adjacent to an N-type semiconductor layer and a P-type semiconductor layer to improve thin film crystallinity of an active layer, and a method of manufacturing the same.

In addition, the present invention is thicker in the region adjacent to the N-type semiconductor layer and the P-type semiconductor layer, and sequentially formed thinner in the inter-region region to the P-type semiconductor layer, so that electrons and holes from the N-type semiconductor layer and the P-type semiconductor layer to the active layer Another object of the present invention is to provide a nitride semiconductor light emitting device and a method of manufacturing the same, which improve the mobility of and improve current dispersion.

In addition, the present invention provides a nitride semiconductor light emitting device and a method of manufacturing the same, which is designed to vary the thickness of the quantum barrier layer and the quantum well layer, but the wavelength is constant to minimize the quality degradation due to the temperature difference and improve the luminous efficiency There is another purpose.

In addition, another object of the present invention is to provide a nitride semiconductor light emitting device having improved electrical characteristics by improving the quality of the boundary portion between the quantum barrier layer and the quantum well layer and improving the recombination efficiency of the injection current, and a method of manufacturing the same. .

Another object of the present invention is to provide a nitride semiconductor light emitting device and a method for manufacturing the same, which improve light emission efficiency by minimizing a quantum confined stark effect and minimize a droop phenomenon.

The nitride semiconductor light emitting device of the present invention for solving the problems of the prior art as described above, N-type semiconductor layer and P-type semiconductor layer; And an active layer interposed between the N-type semiconductor layer and the P-type semiconductor layer and having a multi-quantum well structure in which a plurality of quantum well layers and a plurality of quantum barrier layers are alternately disposed, and the active layer is an N-type semiconductor layer. And a first group of quantum well layers and quantum barrier layers formed in an area adjacent to the P-type semiconductor layer, and a second group of quantum well layers and quantum barrier layers formed in an inner region therebetween. The quantum well layers and the quantum barrier layers of the first group are thicker than the quantum well layers and the quantum barrier layers of the second group.

In addition, the method of manufacturing a nitride semiconductor light emitting device of the present invention comprises the steps of: forming a buffer layer, an undoped semiconductor layer, an N-type semiconductor layer on an insulating substrate; Forming an active layer of a multi-quantum well structure in which a plurality of quantum well layers and a plurality of quantum barrier layers are alternately disposed on the N-type semiconductor layer; Forming a P-type semiconductor layer on the active layer, the active layer comprising a first group of quantum well layers and quantum barrier layers formed in an area adjacent to the N-type semiconductor layer and the P-type semiconductor layer; It is divided into a second group consisting of quantum well layers and quantum barrier layers formed in the inner region therebetween, wherein the first group of quantum well layers and quantum barrier layers are quantum well layers and quantum well layers It is characterized in that the thickness is formed thicker than the barrier layers.

The nitride semiconductor light emitting device and the method of manufacturing the same according to the present invention have a first effect of increasing the thickness of the quantum well layer and the quantum barrier layer adjacent to the N-type semiconductor layer and the P-type semiconductor layer to improve the thin film crystallinity of the active layer. .

In addition, the nitride semiconductor light emitting device and the method of manufacturing the same according to the present invention are thick in the region adjacent to the N-type semiconductor layer and the P-type semiconductor layer, and are sequentially thinned from the interregion to the P-type semiconductor layer, thereby forming the N-type semiconductor layer. And a second effect of improving the mobility of electrons and holes and improving current dispersion from the P-type semiconductor layer to the active layer.

In addition, according to the present invention, the nitride semiconductor light emitting device and the method of manufacturing the same have various thicknesses of the quantum barrier layer and the quantum well layer, but the wavelength is constant to minimize the quality degradation due to the temperature difference and improve the luminous efficiency. 3 is effective.

In addition, the nitride semiconductor light emitting device and the method of manufacturing the same according to the present invention have a fourth effect of improving the electrical characteristics by improving the quality of the boundary portion between the quantum barrier layer and the quantum well layer to increase the effective recombination efficiency of the injection current. .

In addition, the nitride semiconductor light emitting device and the method of manufacturing the same according to the present invention have a fifth effect of improving luminous efficiency and minimizing a droop phenomenon by minimizing a quantum confined stark effect.

1 illustrates a structure of a conventional nitride semiconductor light emitting device.
FIG. 2 is a diagram illustrating an active layer region of the multi-quantum well structure of FIG. 1.
3 is a diagram illustrating quantum efficiency of an active layer of a nitride semiconductor light emitting device.
4 is a diagram illustrating an active layer structure of a multi-quantum well structure according to a first embodiment of the present invention.
5 is a diagram illustrating an active layer structure of a multi-quantum well structure according to a second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are provided as examples to ensure that the spirit of the present invention can be fully conveyed to those skilled in the art. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

The embodiments of the present invention change the structure of the active layer region around the conventional nitride semiconductor light emitting device of FIG. Accordingly, except for the structure of the active layer described below, components of the N-type electrode, the P-type electrode, and the like of the nitride semiconductor light emitting device disclosed in the prior art may be applied to the embodiments of the present invention.

4 is a diagram illustrating an active layer structure of a multi-quantum well structure according to a first embodiment of the present invention.

Referring to FIG. 4, the active layer 150 of the nitride semiconductor light emitting device according to the first embodiment of the present invention is formed in a multi quantum well (MQW) structure as follows. The first quantum well layer 151a, the second quantum well layer 151b, the third quantum well layer 151c, and the fourth quantum well layer between the N-type semiconductor layer 122 and the P-type semiconductor layer 124, respectively. 151d, the fifth quantum well layer 151e, the sixth quantum well layer 151f, the seventh quantum well layer 151g, and the eighth quantum well layer 151h, and the first quantum well layers, respectively. The quantum barrier layer 152a, the second quantum barrier layer 152b, the third quantum barrier layer 152c, the fourth quantum barrier layer 152d, the fifth quantum barrier layer 152e, and the sixth quantum barrier layer 152f. ) And a seventh quantum barrier layer 152g are formed. The active layer 150 has a structure in which quantum barrier layers and quantum well layers are alternately stacked so that electrons and holes recombine and emit light.

The quantum well layers 151a, 151b, 151c, 151d, 151e, 151f, 151g, 151h and the quantum barrier layers 152a, 152b, 152c, 152d, 152e, 152f, 152g are N-type semiconductor layers 122 And a first group formed in an area adjacent to the P-type semiconductor layer 124 and a second group formed therebetween.

The N-type semiconductor layer 122 and the P-type semiconductor layer 124 may be formed of a compound-based group III nitride semiconductor layer such as (Al, In, Ga) N. For example, the N-type semiconductor layer 122 and the P-type semiconductor layer 124 may be N-type and P-type GaN, or N-type or P-type AlGaN, respectively. Although not shown in the figure, a blocking layer may be interposed between the P-type semiconductor layer 124 and the active layer 150. The blocking layer may also be formed of a group III nitride semiconductor layer of (Al, In, Ga) N series, for example, AlGaN. Although not shown, another blocking layer may be interposed between the N-type semiconductor layer 122 and the active layer 150.

In the present invention, the quantum well layers and the quantum barrier layers are formed to have different thicknesses, and the first quantum well layer corresponding to the first group adjacent to the N-type semiconductor layer 122 and the P-type semiconductor layer 124 ( 151a), first quantum barrier layer 152a, second quantum well layer 151b, second quantum barrier layer 152b, sixth quantum barrier layer 152f, seventh quantum well layer 151g, seventh The quantum barrier layer 152g and the eighth quantum well layer 151h have a thickness of the third quantum well layer 151c, the third quantum barrier layer 152c, and the fourth group corresponding to the second group formed therebetween. The quantum well layer 151d, the fourth quantum barrier layer 152d, the fifth quantum well layer 151e, the fifth quantum barrier layer 152e and the sixth quantum well layer 151f are formed thicker than the thickness.

In the present invention, the first group of quantum well layers 151a, 151b, 151g and 151h adjacent to the N-type semiconductor layer 122 and the P-type semiconductor layer 124 and the quantum barrier layers 152a, 152b and 152f. 152g) The thickness and the thickness of the second group of quantum well layers 151c, 151d, 151e and 151f and the quantum barrier layers 152c, 152d and 152e formed therebetween are different from each other. It is formed to have a wavelength.

That is, as shown in FIG. 4, in the energy band gap of the active layer 150 of the nitride semiconductor light emitting device according to the first embodiment, the quantum well layers 151c, 151d, 151e, and 151f of the second group are N. FIG. The band gap is narrower than that of the first group of quantum well layers 151a, 151b, 151g, and 151h adjacent to the P-type semiconductor layer 122 and the P-type semiconductor layer 124, so that the emission wavelengths of all the quantum well layers are constant. Is formed.

Further, the quantum well layers 151c, 151d, 151e and 151f and the quantum barrier layers 152c and 152d in the second group of the active layer 150 of the multi-quantum well structure according to the first embodiment of the present invention. Although the thickness of 152e is thinner than the thickness of the first group of quantum well layers 151a, 151b, 151g and 151h and the quantum barrier layers 152a, 152b, 152f and 152g, it is due to the quantization phenomenon of the electron distribution function. The emission wavelengths are formed equal to each other.

The quantum barrier layers are made of Al _{x In y} Ga _(1-xy) N (0 ≦ x ≦ 1,0 <y ≦ 1,0 <x + y ≦ 1), and the quantum well layers are formed of In _z Ga _{(1- z)} N (0 ≦ _z ≦ 1). In this case, the thickness of the first group of quantum barrier layers and the quantum well layers may be formed by adjusting the composition of In. Alternatively, the thickness may be increased by increasing the growth temperature of the second group of quantum barrier layers and the quantum well layers. However, the present invention is not limited thereto, and the number of all quantum barrier layers and quantum well layers including the first group and the second group is not limited to the drawings.

Thus, the quantum well layers and the quantum barrier layers of the first group are formed thicker than the thicknesses of the quantum well layers and the quantum barrier layers of the second group, but the emission wavelength is formed uniformly, thereby improving the thin film crystallinity of the active layer. The electrons and holes injected from the N-type semiconductor layer and the P-type semiconductor layer into the active layer are formed to improve the flow of the electrons and holes and to facilitate current dispersion. In addition, the quality deterioration due to the temperature difference between the N-type semiconductor layer and the P-type semiconductor layer can be minimized.

5 is a diagram illustrating an active layer structure of a multi-quantum well structure according to a second embodiment of the present invention.

Referring to FIG. 5, the active layer 250 of the nitride semiconductor light emitting device according to the second embodiment of the present invention is formed in a multi quantum well (MQW) structure as follows. Between the N-type semiconductor layer 122 and the P-type semiconductor layer 124, the first quantum well layer 251a, the second quantum well layer 251b, the third quantum well layer 251c, and the fourth quantum well layer ( 251d), the fifth quantum well layer 251e, the sixth quantum well layer 251f, and the seventh quantum well layer 251g, and the first quantum barrier layer 252a and the second quantum barrier layer, respectively. The layer 252b, the third quantum barrier layer 252c, the fourth quantum barrier layer 252d, the fifth quantum barrier layer 252e and the sixth quantum barrier layer 252f are formed. The active layer 250 has a structure in which quantum barrier layers and quantum well layers are alternately stacked so that electrons and holes recombine and emit light.

The quantum well layers 251a, 251b, 251c, 251d, 251e, 251f and 251g and the quantum barrier layers 252a, 252b, 252c, 252d, 252e and 252f are formed of an N-type semiconductor layer 122 and a P-type semiconductor. A third group formed in the region adjacent to layer 124 and a fourth group formed therein.

The N-type semiconductor layer 122 and the P-type semiconductor layer 124 may be formed of a compound-based group III nitride semiconductor layer such as (Al, In, Ga) N. For example, the N-type semiconductor layer 122 and the P-type semiconductor layer 124 may be N-type and P-type GaN, or N-type or P-type AlGaN, respectively. Although not shown in the figure, a blocking layer may be interposed between the P-type semiconductor layer 124 and the active layer 250. The blocking layer may also be formed of a group III nitride semiconductor layer of (Al, In, Ga) N series, for example, AlGaN. In addition, although not shown in the figure, another blocking layer may be interposed between the N-type semiconductor layer 122 and the active layer 250.

In the second embodiment of the present invention, as in the first embodiment, the thicknesses of the quantum barrier layers and the quantum well layers of the third group are formed differently from the thicknesses of the quantum barrier layers and the quantum well layers of the fourth group. . That is, the first quantum well layer 251a, the first quantum barrier layer 252a, and the second quantum well layer 251b corresponding to the third group adjacent to the N-type semiconductor layer 122 and the P-type semiconductor layer 124. ), The thickness of the second quantum barrier layer 252b, the sixth quantum barrier layer 252f, and the seventh quantum well layer 251g is the third quantum well layer 251c corresponding to the fourth group formed therebetween. ), The third quantum barrier layer 252c, the fourth quantum well layer 251d, the fourth quantum barrier layer 252d, the fifth quantum well layer 251e, the fifth quantum barrier layer 252e, and the sixth quantum It is formed thicker than the thickness of the well layer 251f.

However, in the second embodiment of the present invention, unlike in the first embodiment, the thicknesses of the quantum well layers 251c, 251d, 251e and 251f are not constant, and the quantum barrier layers 252c, 252d and 252e are different. ) Is constant, but the thicknesses of the quantum well layers 251c, 251d, 251e, and 251f gradually decrease from the N-type semiconductor layer 122 to the P-type semiconductor layer 124.

That is, the thicknesses of the quantum well layers 251a, 251b and 251g and the quantum barrier layers 252a, 252b and 252f adjacent to the N-type semiconductor layer 122 and the P-type semiconductor layer 124 are the thickest, and the fourth In the group, the third quantum well layer 251c, the fourth quantum well layer 251d, the fifth quantum well layer 251e, and the sixth quantum well layer 251f are formed so as to become thinner.

The fourth group of quantum well layers may be formed in various thicknesses, but as in the first embodiment, the second quantum well layers may have the same emission wavelength in the entire active layer 250 including the third group and the fourth group. do.

That is, as shown in FIG. 5, when looking at the energy band gap of the active layer 250 of the nitride semiconductor light emitting device according to the second embodiment, the fourth group of quantum well layers 251c, 251d, 251e, and 251f are formed. The bandgap is narrower than that of the three groups of quantum well layers 251a, 251b, and 251g, and thus the emission wavelength is the same due to the quantization phenomenon of the electron distribution function of all the quantum well layers.

The quantum barrier layers are made of Al _{x In y} Ga _(1-xy) N (0 ≦ x ≦ 1,0 <y ≦ 1,0 <x + y ≦ 1), and the quantum well layers are formed of In _z Ga _{(1- z)} N (0 ≦ _z ≦ 1). At this time, by adjusting the composition of In, the thickness of the third group of quantum barrier layers and quantum well layers can be formed thick. Alternatively, the thickness may be increased by increasing the growth temperature of the fourth group of quantum barrier layers and the quantum well layers. However, this is not limited to this as one method, and the number of all quantum barrier layers and quantum well layers including the third group and the fourth group is not limited to the drawings.

Thus, as in the first embodiment, the quantum well layers and the quantum barrier layers of the third group are formed thicker than the thicknesses of the quantum well layers and the quantum barrier layers of the fourth group, but the emission wavelength is formed to be constant. The thin film crystallinity is improved, the flow of electrons and holes injected from the N-type semiconductor layer and the P-type semiconductor layer into the active layer is improved, and the current distribution is easy, and the temperature difference between the N-type semiconductor layer and the P-type semiconductor layer There is an effect that can minimize the deterioration of quality.

In addition, since the quantum well layers are sequentially thinned in the fourth group, it is possible to minimize the quantum confined stark effect and to minimize the droop phenomenon occurring at a high current. When adopted as a quantum well layer and a quantum barrier layer having a relatively narrow bandgap can reduce the quantum confinement effect can improve the recombination rate of electrons and holes.

In the manufacturing method of the nitride semiconductor device according to the first and second embodiments of the present invention, the insulating substrate is cleaned by high temperature heat treatment in a hydrogen (H ₂ ) atmosphere. At this time, the heat treatment temperature is 1000 ° C to 1200 ° C, and the formation temperature of the buffer layer is preferably 500 ° C to 600 ° C. The insulating substrate may be formed of zinc oxide (ZnO), gallium nitride (GaN), silicon carbide (SiC), aluminum nitride (AlN), and the like, which are transparent materials including sapphire.

Thereafter, the buffer layer is crystallized at a high temperature, and then an undoped semiconductor layer and an N-type semiconductor layer 122 are formed. At this time, the temperature is preferably 1000 ℃ ~ 1200 ℃, the undoped semiconductor layer is 0.5 ~ 2.0um, the N-type semiconductor layer may be formed within 2.0um.

Then, the active layer is formed in a multi-quantum well structure at a temperature lower than the growth temperature of the N-type semiconductor layer 122. Temperature is preferably 700 ℃ ~ 800 ℃, the active layer is grown so that two or more quantum well layer and quantum barrier layer intersect. At this time, the quantum well layer and the quantum barrier layer adjacent to the N-type semiconductor layer 122 and the P-type semiconductor layer 124 are grown thickest by one cycle or more, while the quantum well layer and the quantum barrier layer grow thinner than this. do. However, the emission wavelengths of all the quantum well layers and the quantum barrier layers are grown to be the same. Such a multi-quantum well structure means a quantum barrier layer and a quantum well layer described in the first and second embodiments of the present invention, and the specific design range thereof has been described in each embodiment.

As such, when the multi-quantum well structure is formed, the temperature is raised again to form the P-type semiconductor layer 124, and after the growth of the P-type semiconductor layer 124, the N-type electrode and the P-type electrode are formed to complete the nitride semiconductor device. do. In this case, a transparent metal layer may be formed between the P-type semiconductor layer 124 and the P-type electrode.

Therefore, the nitride semiconductor light emitting device and the method of manufacturing the same according to the present invention are formed by increasing the thickness of the quantum well layer and the quantum barrier layer adjacent to the N-type semiconductor layer and the P-type semiconductor layer, but the emission wavelength is the same in all areas, By improving the thin film crystallinity of the active layer and forming the quantum well layer gradually thinner from the inner region to the P-type semiconductor layer, improve the mobility of electrons and holes from the N-type and P-type semiconductor layer to the active layer and improve the current Improves dispersion. In addition, minimizing the quality degradation caused by the temperature difference when forming the N-type semiconductor layer and the P-type semiconductor layer and the active layer, improving luminous efficiency, and improving the quality of the boundary portion, improve the effective recombination efficiency of the injection current to improve the electrical characteristics. It can be improved. In addition, the luminous efficiency is improved by minimizing the quantum confined stark effect and the droop phenomenon is minimized.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

122: N-type semiconductor layer 124: P-type semiconductor layer
150,250: active layer 151,251: quantum well layer
152,252: quantum barrier layer

Claims (10)

An N-type semiconductor layer and a P-type semiconductor layer; And
An active layer interposed between the N-type semiconductor layer and the P-type semiconductor layer and having a multi-quantum well structure in which a plurality of quantum well layers and a plurality of quantum barrier layers are alternately disposed;
The active layer includes a first group of quantum well layers and quantum barrier layers formed in an area adjacent to an N-type semiconductor layer and a P-type semiconductor layer, and quantum well layers and quantum barrier layers formed in an inner region therebetween. Divided into a second group consisting of
The quantum well layers and the quantum barrier layers of the first group is thicker than the quantum well layers and quantum barrier layers of the second group. The method of claim 1,
The first group and the second group are nitride semiconductor light emitting device, characterized in that formed with a thickness having the same emission wavelength. The method of claim 1,
And the quantum well layers and the quantum barrier layers of the second group are formed to have a predetermined thickness, and the first group and the second group are formed to have the same emission wavelength. The method of claim 1,
The thickness of the quantum well layers of the second group is sequentially thinner from the N-type semiconductor layer to the P-type semiconductor layer, and the thickness of the quantum barrier layers of the second group is formed to have a constant thickness, and the first group and The second group is nitride semiconductor light emitting device, characterized in that formed with a thickness having the same emission wavelength. Forming a buffer layer, an undoped semiconductor layer, and an N-type semiconductor layer on the insulating substrate;
Forming an active layer of a multi-quantum well structure in which a plurality of quantum well layers and a plurality of quantum barrier layers are alternately disposed on the N-type semiconductor layer;
Forming a P-type semiconductor layer on the active layer,
The active layer includes a first group of quantum well layers and quantum barrier layers formed in an area adjacent to an N-type semiconductor layer and a P-type semiconductor layer, and quantum well layers and quantum barrier layers formed in an inner region therebetween. Divided into a second group consisting of
The quantum well layers and the quantum barrier layers of the first group are formed thicker than the quantum well layers and quantum barrier layers of the second group. The method of claim 5, wherein
The first group and the second group are nitride semiconductor light emitting device, characterized in that formed with a thickness having the same wavelength. The method of claim 5, wherein
The quantum well layer and the quantum barrier layer of the second group is formed to have a constant thickness, the first group and the second group is a nitride semiconductor light emitting device, characterized in that formed with a thickness having the same emission wavelength. The method of claim 5, wherein
The thickness of the quantum well layers of the second group is sequentially thinner from the N-type semiconductor layer to the P-type semiconductor layer, and the thickness of the quantum barrier layers of the second group is formed to have a constant thickness, and the first group and The second group is nitride semiconductor light emitting device, characterized in that formed with a thickness having the same emission wavelength. The method of claim 5, wherein
The quantum barrier layers of the first group and the second group are made of Al _{x In y} Ga _(1-xy) N (0 ≦ x ≦ 1,0 <y ≦ 1,0 <x + y ≦ 1) The well layers consist of In _z Ga _(1-z) N (0 ≦ _z ≦ 1),
The quantum well layers and the quantum barrier layers of the first group are formed to be thicker than the quantum well layers and quantum barrier layers of the second group by controlling the composition of In. The method of claim 5, wherein
The quantum well layers and the quantum barrier layers of the first group are formed at a higher temperature than the quantum well layers and the quantum barrier layers of the second group, thereby making them thicker than the quantum well layers and the quantum barrier layers of the second group. Forming a nitride semiconductor light emitting device characterized in that it is formed.

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