KR102212775B1 - Light emitting device and lighting system - Google Patents

Abstract

The embodiment relates to a light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system.
The light emitting device according to the embodiment includes a first conductivity type semiconductor layer; A first active layer having a first quantum wall having a first band gap energy on the first conductivity type semiconductor layer; A second active layer having a second quantum wall having a second band gap energy smaller than the first band gap energy on the first active layer; And a second conductivity type semiconductor layer on the second active layer.

Description

Light emitting device and lighting system {LIGHT EMITTING DEVICE AND LIGHTING SYSTEM}

The embodiment relates to a light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system.

A light emitting device may be generated by combining a group III and a group V element on the periodic table with a p-n junction diode that converts electric energy into light energy. LED can realize various colors by controlling the composition ratio of the compound semiconductor.

When a forward voltage is applied, the electrons in the n-layer and the holes in the p-layer are combined to emit energy equivalent to the energy gap between the conduction band and the balance band. It is mainly emitted in the form of heat or light, and when it is emitted in the form of light, it becomes a light emitting device.

For example, nitride semiconductors are attracting great interest in the development of optical devices and high-power electronic devices due to their high thermal stability and wide band gap energy. In particular, a blue light-emitting device, a green light-emitting device, and an ultraviolet (UV) light-emitting device using a nitride semiconductor are commercialized and widely used.

In the conventional light emitting device, the active layer, which is a light emitting layer, is formed by repeatedly stacking an InGaN quantum well with a small energy band gap and a GaN quantum wall with a large energy band gap, and electrons injected from the n-layer and holes injected from the p-layer. In this quantum well, they meet each other and emit light by emitting light.

On the other hand, the light emitting device of the conventional structure has a problem in that the luminous efficiency decreases when the amount of injection current increases, which is due to the low hole injection efficiency compared to the electron injection efficiency in the emission layer.

Specifically, holes have a relatively large effective mass compared to electrons and have low mobility, and the activation energy of the p-type dopant is large, so that the hole concentration in the p-layer is low.

On the other hand, since electrons have a relatively small effective mass and high mobility, the activation energy of the p-type dopant is small and the electron concentration in the n-layer is high.

Eventually, when electrons and holes are injected into the light-emitting layer, electrons effectively move in the p-layer direction in the light-emitting layer, whereas holes cannot effectively move in the n-layer direction within the light-emitting layer, so that electrons and holes are mainly adjacent to the p-layer. They meet each other in the emission layer and mainly emit light.

This charge asymmetry eventually reduces the number of quantum wells that actually participate in light emission, thereby reducing the effective light emitting area. This decrease in the effective light emitting area increases electron overflow from the light emitting layer to the p-layer, and causes a problem in that the Auger non-emission recombination phenomenon increases in the light emitting layer, so that the luminous efficiency decreases.

Therefore, in order to provide a high-efficiency nitride semiconductor light-emitting device by solving the issue of lowering the luminous efficiency that occurs when the injection current increases, holes are uniformly distributed in the light-emitting layer by effectively moving holes from the p-layer toward the n-layer in the light-emitting layer. And, through this, there is a need to develop a technology that allows all quantum wells in the light-emitting layer to participate in light emission.

The embodiment is to provide a high-efficiency nitride semiconductor light emitting device capable of solving the issue of lowering of luminous efficiency occurring when an injection current is increased, a manufacturing method thereof, a light emitting device package, and a lighting system.

The light emitting device according to the embodiment includes a first conductivity type semiconductor layer 112; A first active layer 110 including a first quantum wall 110B having a first band gap energy on the first conductivity type semiconductor layer 112; A second active layer 120 including a second quantum wall 115B having a second band gap energy smaller than the first band gap energy on the first active layer 110; And a second conductivity type semiconductor layer 116 on the second active layer 120.

The lighting system according to the embodiment may include a light emitting unit including the light emitting device.

According to the light emitting device, the manufacturing method of the light emitting device, the light emitting device package, and the lighting system according to the embodiment, the effective light emitting area is increased by making the hole distribution uniform in the active layer, and excellent luminous efficiency can be provided when high current is injected. .

1 is a cross-sectional view of a light emitting device according to an embodiment.
2 is an exemplary diagram of a band gap energy of a light emitting device according to the first embodiment.
3 is an exemplary view of distribution of holes in an active layer of a light emitting device according to the prior art.
4 is an exemplary view of distribution of holes in an active layer of a light emitting device according to an embodiment.
5 is a diagram illustrating hole mobility in an active layer of a light emitting device according to the prior art.
6 is an exemplary diagram of hole mobility in an active layer of a light emitting device according to an embodiment.
7 is a comparison diagram of the internal quantum efficiency according to the current of the embodiment and the conventional light emitting device.
Figure 8 is a comparison diagram of the internal quantum efficiency of the light emitting device of the embodiment and the prior art.
9 is an exemplary diagram of a band gap energy of a light emitting device according to the second embodiment.
10 is an exemplary diagram of a band gap energy of a light emitting device according to a third embodiment.
11 is an exemplary diagram of a band gap energy of a light emitting device according to a fourth embodiment.
12 to 14 are manufacturing process diagrams of a light emitting device according to the embodiment.
15 is a cross-sectional view of a light emitting device package according to an embodiment.
16 is an exploded perspective view of a lighting device according to the embodiment.

In the description of the embodiment, each layer (film), region, pattern, or structure is "on/over" or "under" of the substrate, each layer (film), region, pad, or patterns. In the case of being described as being formed in, "on/over" and "under" include both "directly" or "indirectly" formed do. In addition, standards for the top/top or bottom of each layer will be described based on the drawings.

(Example)

1 is a cross-sectional view of a light emitting device 100 according to an embodiment, and FIG. 2 is an exemplary diagram of a band gap energy diagram of a light emitting device according to the first embodiment.

As shown in FIG. 1, the light emitting device 100 according to the embodiment includes a first conductivity type semiconductor layer 112 and an active layer 130 on the first conductivity type semiconductor layer 112 and the active layer 130. A second conductivity type semiconductor layer 116 may be included. The first conductivity type semiconductor layer 112, the active layer 130, and the second conductivity type semiconductor layer 116 may be referred to as a light emitting structure 150.

In the embodiment, an aluminum gallium-based nitride semiconductor layer 160 is provided between the active layer 130 and the second conductive semiconductor layer 116 to increase luminous efficiency through an electron blocking function.

The embodiment may include a light-transmitting electrode 170 on the second conductivity type semiconductor layer 116, and are electrically connected to the second conductivity type semiconductor layer 116 and the first conductivity type semiconductor layer 112, respectively. A second electrode 152 and a first electrode 151 may be included.

The embodiment may be a horizontal light emitting device in which the light emitting structure 150 is disposed on a substrate 102 as shown in FIG. 1, but is not limited thereto, and may be applied to a vertical light emitting device.

The embodiment is to provide a high-efficiency nitride semiconductor light emitting device capable of solving the issue of lowering the luminous efficiency that occurs when the injection current increases.

To this end, as shown in FIG. 2, in the light emitting device according to the embodiment, the active layer 130 includes a first active layer 110 having a first band gap energy 　 having a first quantum wall 110B, and the first active layer 110. A second active layer 120 having a second quantum wall 120B having a second band gap energy smaller than the first band gap energy may be included on ).

In the light emitting device 100 according to the embodiment, the first quantum wall 110B of the first active layer 110 is a first Al _x Ga _y In _1-xy N quantum wall (however, 0 <x≤1, 0≤y 1) 115B.

The first quantum wall 110B of the first active layer 110 includes a plurality of first GaN quantum walls 111B, and the first Al _x Ga _y In _{1 -x- y} N quantum wall 115B is It may be disposed between the first GaN quantum walls 111B.

For example, the first active layer 110 includes a first In _x Ga _{1 - x} N quantum well (however, 0 <x <1) (110W), a first GaN quantum wall (111B), and a first Al _x Ga _y In _{1 -x- y} N quantum walls 115B and first GaN quantum walls 111B may be included.

The second active layer 120 may include a second In _x Ga _{1 - x} N quantum well 120W and a second GaN quantum wall 120B.

In an embodiment, the first conductivity-type semiconductor layer 112 is an n-type semiconductor layer, and the first active layer 110 is adjacent to the first conductivity-type semiconductor layer 112 compared to the second active layer 120. Can be placed.

In the embodiment, the energy band gap of the first Al _x Ga _y In _{1 -x- y} N quantum wall 115B containing Al is greater than the energy band gap of the second GaN quantum wall 120B in the second active layer 120. It can be big.

In the light emitting device according to the embodiment, a nitride semiconductor thin film layer containing Al has a material property having a higher hole mobility than a nitride semiconductor thin film layer not containing Al.

Therefore, holes injected into the active layer 130 from the second conductivity-type semiconductor layer 116, which is a p-layer, pass through the second active layer 120, and are adjacent to the first conductivity-type semiconductor layer 112, which is an n-type electron injection layer. It is possible to move more effectively to the region of the first active layer 110.

Through this, the effective light emitting area is increased by making the hole distribution in the active layer more uniform, and as a result, excellent luminous efficiency can be provided when high current is injected.

In an embodiment the number of first active layers (110) in claim _{1 Al x Ga y In 1 -x-} y N quantum wall (115B) is equal to the number of the second active layer 120 in the second GaN quantum wall (120B) Or it can be smaller.

Example In a _{1 Al x Ga y In 1 -x-} y N quantum wall (115B) comprises an Al, the thickness of about 0.5 to from about 5nm range.

In the embodiment, if the thickness of the first Al _x Ga _y In _{1 -x- y} N quantum wall 115B is less than 0.5 nm, the hole mobility cannot be effectively improved, and if the thickness is greater than 5 nm, the electron mobility is reduced. Thus, there may be a problem that the injection efficiency of electrons decreases.

In addition, in the case of a blue light emitting device according to an embodiment, the Al content in the first Al _x Ga _y In _{1 -x- y} N quantum wall 115B may be 1% to 25%. When the Al composition is at least 1% or more, hole mobility can be effectively improved, and when the Al composition exceeds 25%, there is a problem that the injection efficiency of electrons is low, and compressive stress may be caused in the quantum well.

3 is a diagram illustrating an exemplary distribution of holes in an active layer of a light emitting device according to the prior art, and FIG. 4 is a diagram illustrating an exemplary distribution of holes in an active layer of a light emitting device according to an embodiment.

As shown in FIG. 3, in the conventional light emitting device, many holes are distributed in a quantum well adjacent to the p-layer. On the other hand, a relatively small number of holes are distributed in quantum wells adjacent to the n-layer.

That is, in the prior art, the concentration of holes present in the quantum well shows that the concentration of holes decreases from the p-layer toward the n-layer.

On the other hand, in the light emitting device according to the embodiment as shown in FIG. 4, not only quantum wells adjacent to the second conductivity-type semiconductor layer 116, which is a p-layer, but also quantum wells adjacent to the first conductivity-type semiconductor layer 112, which is an n-layer. It shows that a sufficiently large number of holes are distributed in the interior.

According to the examples, the concentration of holes present in the quantum well shows that there is little decrease in the hole concentration from the p-layer toward the n-layer.

Accordingly, according to an embodiment, holes injected into the active layer 130 from the second conductivity-type semiconductor layer 116, which is a p-layer, pass through the second active layer 120, and pass through the first conductivity-type semiconductor layer, which is an n-type electron injection layer. It is possible to move more effectively to the region of the first active layer 110 adjacent to 112, thereby increasing the effective light emitting area by making the hole distribution in the active layer more uniform, and consequently, excellent luminous efficiency can be provided when high current is injected. .

5 is an exemplary diagram illustrating hole mobility in an active layer of a light emitting device according to the prior art, and shows the distribution of hole mobility in an active layer of a nitride semiconductor light emitting device having an active layer having a conventional structure.

According to the prior art, it shows that the hole mobility in the active layer as a whole is low.

On the other hand, FIG. 6 is an exemplary diagram of hole mobility in the active layer of the light emitting device according to the embodiment, and shows high hole mobility in the active layer of the nitride semiconductor light emitting device having the active layer structure according to the embodiment.

According to the embodiment, the mobility of holes in the quaternary Al _x Ga _y In _1-xy N quantum wall 115B in the first two quantum wall structures from the n-GaN layer side is relatively high.

Therefore, according to the embodiment, it means that holes injected from the second conductivity-type semiconductor layer 116 as the p-layer into the active layer can be more effectively transported in the direction of the first conductivity-type semiconductor layer 112 as the n-layer within the active layer. do.

7 is a diagram illustrating a comparison of internal quantum efficiency according to an injection current of a light emitting device in the embodiment and the prior art.

For example, at an injection current of about 100A/cm ³ , when the prior art (R) is applied, the internal emission quantum efficiency is about 0.56, whereas in the light emitting device according to the embodiment, the Al concentration is about 2% Al _x Ga _y In ₁ when _{-x- y} N quantum wall application (E1), the internal quantum efficiency was improved by about 0.67 to about 20%, Al concentration of the _{Al x Ga y in 1 -x- y} N quantum wall during application (E2) of about 15% The internal quantum efficiency was about 0.90, which was significantly improved by more than about 60%.

8 is a comparison diagram of internal quantum efficiency at an injection current of about 100A/cm ³ of a light emitting device of the embodiment and the prior art.

When the conventional technology (R) is applied, the internal emission quantum efficiency is 0.56, whereas when _one Al _x Ga _y In _{1 -x- y} N quantum wall with an Al concentration of about 15% is applied (Ea), the internal emission quantum efficiency (IQE ) Was improved by about 52% to about 0.85, and when two Al _x Ga _y In _{1 -x- y} N quantum walls with an Al concentration of about 15% were applied (Eb), the internal emission quantum efficiency (IQE) was about 0.90. It was improved to about 60%, and when four Al _x Ga _y In _1-xy N quantum walls with an Al concentration of about 15% were applied (Ec), the IQE was maintained to be about 0.90, 60% improvement. Since Al can induce compressive stress in In, the Al _x Ga _y In _{1 -x- y} N quantum wall 115B is distributed less than about 50% of the entire quantum wall of the active layer 130 to maximize the internal quantum efficiency. While minimizing the induction of stress.

9 is an exemplary diagram illustrating a band gap energy diagram of a light emitting device according to the second embodiment.

The second embodiment can adopt the technical features of the first embodiment.

In the second embodiment, the first quantum wall 110B includes a plurality of Al _x Ga _y In _{1 -x- y} N quantum walls 115B and 116B, and the Al _x Ga _y In _1-xy N quantum wall The concentration of Al in may decrease from the first conductivity type semiconductor layer 112 to the second conductivity type semiconductor layer 116.

In addition, in the plurality of Al _x Ga _y In _1-xy N quantum walls 115B, the band gap energy of the Al _x Ga _y In _1-xy N quantum wall 115B is the first conductivity type semiconductor layer 112 ) May decrease in the direction of the second conductivity type semiconductor layer 116.

For example, the first quantum wall 110B may include an A quantum wall 111B and a B quantum wall 112B from the first conductivity type semiconductor layer 112, and the A quantum wall 111B And the B quantum wall 112B may each include a first Al _x Ga _y In _1-xy N quantum wall 115B and a second Al _x Ga _y In _1-xy N quantum wall 116B.

In an embodiment, the Al concentration or bandgap energy of the second Al _x Ga _y In _1-xy N quantum wall 116B is the Al concentration of the first Al _x Ga _y In _1-xy N quantum wall 115B or It may be lower than the bandgap energy.

Through this, considering that the hole injection efficiency decreases as the distance from the second conductivity-type semiconductor layer 116 decreases, the Al concentration or the bandgap energy of the Al _x Ga _y In _1-xy N quantum wall gradually increases. , It is possible to maximize the hole injection efficiency while minimizing the occurrence of defects due to differences in lattice constants.

10 is an exemplary diagram illustrating a band gap energy diagram of a light emitting device according to a third embodiment.

The third embodiment can adopt the technical features of the first embodiment or the second embodiment.

In the third embodiment, the first quantum wall 110B may include a plurality of Al _x Ga _y In _{1 -x- y} N quantum walls 117B and 118B, and the Al _x Ga _y In _{1 -x- y} N quantum wall thickness can vary from the first conductive type semiconductor layer 112 to the second conductive type semiconductor layer (116) direction.

For example, the first quantum wall 110B has a first Al _x Ga _y In _1-xy N quantum wall 117B and a second thickness W1 from the first conductivity type semiconductor layer 112. the thickness (W2) a second Al _x Ga _y in _1-xy N may comprise a quantum wall (118B), a second thickness (W2 of the second Al _x Ga _y in _1-xy N quantum wall (118B) of ) May be greater than the first thickness W1 of the first Al _x Ga _y In _1-xy N quantum wall 117B.

In the case of the same concentration in terms of energy level, the thickness of the quantum wall is inversely proportional to the energy level.In the third embodiment, the quaternary Al _x Ga _y In _1-xy N quantum wall, for example, at least the first Al _x Ga _y In _1-xy N quantum wall (117B) by reducing the thickness of the second Al _x Ga _y In _1-xy N quantum wall (118B) by increasing the energy level, between the first binary GaN quantum wall (111B) By minimizing the distribution of the quaternary Al _x Ga _y In _1-xy N quantum walls, the hole injection efficiency can be maximized while minimizing defects.

11 is an exemplary diagram illustrating a band gap energy diagram of a light emitting device according to a fourth embodiment.

The fourth embodiment can adopt the technical features of the first to third embodiments.

In the fourth embodiment, the first quantum wall 113B may include a third Al _x Ga _y In _1-xy N quantum wall 119B, and the third Al _x Ga _y In _{1 -x- y} N The energy level between the quantum wall 119B and the first GaN quantum wall 111B may gradually change.

For example, an energy level between the third Al _x Ga _y In _{1 -x- y} N quantum wall 119B and the first GaN quantum wall 111B may be inclined.

According to the fourth embodiment, the energy level between the third Al _x Ga _y In _1-xy N quantum wall 119B and the first GaN quantum wall 111B gradually changes, thereby reducing lattice defects and improving lattice quality. As a result, the hole injection efficiency can be further increased, and the luminous intensity can be remarkably increased.

According to the light emitting device, the manufacturing method of the light emitting device, the light emitting device package, and the lighting system according to the embodiment, the effective light emitting area is increased by making the hole distribution uniform in the active layer, and excellent luminous efficiency can be provided when high current is injected. .

Hereinafter, while describing the manufacturing process of the light emitting device according to the embodiment with reference to FIGS. 12 to 14, the characteristics of the light emitting device according to the embodiment will be described in more detail.

First, as shown in FIG. 12, a growth substrate 102 is prepared. The substrate 102 may be formed of a material having excellent thermal conductivity, and may be a conductive substrate or an insulating substrate.

For example, the substrate 102 may use at least one of sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, and Ga ₂ 0 ₃ . An uneven structure may be formed on the substrate 102, but the embodiment is not limited thereto.

In this case, a buffer layer (not shown) may be formed on the substrate 102. The buffer layer may alleviate lattice mismatch between the material of the light emitting structure 150 and the substrate 102 to be formed later, and the material of the buffer layer is a group 3-5 compound semiconductor such as GaN, InN, AlN, InGaN, AlGaN , InAlGaN, AlInN may be formed of at least one.

Next, a light emitting structure 150 including a first conductivity type semiconductor layer 112, an active layer 130, and a second conductivity type semiconductor layer 116 may be formed on the first substrate 102.

The first conductivity type semiconductor layer 112 may be formed of a semiconductor compound. It may be implemented with a compound semiconductor such as Group 3-5 and Group 2-6, and may be doped with a first conductivity type dopant. When the first conductivity-type semiconductor layer 112 is an n-type semiconductor layer, the first conductivity-type dopant is an n-type dopant, and may include Si, Ge, Sn, Se, and Te, but is not limited thereto.

The first conductivity type semiconductor layer 112 may include a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0≤x≤1, 0≤y≤1, 0≤x+y≤1). I can.

The first conductivity type semiconductor layer 112 may be formed of one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP, InP.

The active layer 130 may be formed of at least one of a single quantum well structure, a multi quantum well (MQW) structure, a quantum-wire structure, or a quantum dot structure. For example, in the active layer 130, trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) may be injected to form a multiple quantum well structure. It is not limited thereto.

The active layer 130 has a pair structure of at least one of AlInGa/AlInGaN, InGaN/GaN, InGaN/InGaN, GaN/AlGaN, InGaN/AlGaN, InAlGaN/GaN, GaAs(InGaAs)/AlGaAs, GaP(InGaP)/AlGaP. It may be formed, but is not limited thereto.

The embodiment is to provide a high-efficiency nitride semiconductor light emitting device capable of solving the issue of lowering the luminous efficiency that occurs when the injection current increases.

Hereinafter, technical features of the embodiment will be described in more detail with reference to FIGS. 2, 9, 10, and 11.

As shown in FIG. 2, in the light emitting device according to the first embodiment, the active layer 130 includes a first active layer 110 having a first band gap energy 　 having a first quantum wall 110B, and the first active layer 110. A second active layer 120 having a second quantum wall 115B having a second band gap energy smaller than the first band gap energy may be included on ).

In the light emitting device 100 according to the embodiment, the first quantum wall 110B of the first active layer 110 is a first Al _x Ga _y In _1-xy N quantum wall (however, 0 <x≤1, 0≤y 1) 115B.

The first quantum wall 110B of the first active layer 110 includes a plurality of first GaN quantum walls 111B, and the first Al _x Ga _y In _1-xy N quantum wall 115B is the first quantum wall 115B. It may be disposed between the 1 GaN quantum walls 111B.

For example, the first active layer 110 includes a first In _x Ga _1-x N quantum well (however, 0<x<1) (110W), a first GaN quantum wall 111B, and a first Al _x Ga _{A y} In _1-xy N quantum wall 115B and a first GaN quantum wall 111B may be included.

The second active layer 120 may include a second In _x Ga _1-x N quantum well 120W and a second GaN quantum wall 120B.

In an embodiment, the first conductivity-type semiconductor layer 112 is an n-type semiconductor layer, and the first active layer 110 is adjacent to the first conductivity-type semiconductor layer 112 compared to the second active layer 120. Can be placed.

In an embodiment, the energy band gap of the first Al _x Ga _y In _1-xy N quantum wall 115B containing Al may be larger than the energy band gap of the second GaN quantum wall 120B in the second active layer 120. have.

In the light emitting device according to the embodiment, a nitride semiconductor thin film layer containing Al has a material property having a higher hole mobility than a nitride semiconductor thin film layer not containing Al.

Therefore, holes injected into the active layer 130 from the second conductivity-type semiconductor layer 116, which is a p-layer, pass through the second active layer 120, and are adjacent to the first conductivity-type semiconductor layer 112, which is an n-type electron injection layer. It is possible to move more effectively to the region of the first active layer 110.

Through this, the effective light emitting area is increased by making the hole distribution in the active layer more uniform, and as a result, excellent luminous efficiency can be provided when high current is injected.

In the embodiment, the number of first Al _x Ga _y In _1-xy N quantum walls 115B in the first active layer 110 is equal to or greater than the number of second GaN quantum walls 120B in the second active layer 120. It can be small.

In an embodiment, the first Al _x Ga _y In _1-xy N quantum wall 115B includes Al, and its thickness may range from about 0.5 to about 5 nm. In the embodiment, if the thickness of the first Al _x Ga _y In _1-xy N quantum wall 115B is less than 0.5 nm, the hole mobility cannot be effectively improved, and if the thickness is greater than 5 nm, the electron mobility is reduced to reduce the electron mobility. There may be a problem that the injection efficiency of is lowered.

In addition, in the case of a blue light emitting device according to an embodiment, the Al content in the first Al _x Ga _y In _1-xy N quantum wall 115B may be 1% to 25%. When the Al composition is at least 1% or more, hole mobility can be effectively improved, and when the Al composition exceeds 25%, there is a problem that the injection efficiency of electrons is low, and compressive stress may be caused in the quantum well.

4, in the light emitting device according to the embodiment, not only quantum wells adjacent to the second conductivity-type semiconductor layer 116, which is a p-layer, but also quantum wells adjacent to the first conductivity-type semiconductor layer 112, which is an n-layer. Figure shows that a sufficient number of holes are distributed.

Accordingly, according to an embodiment, holes injected into the active layer 130 from the second conductivity-type semiconductor layer 116, which is a p-layer, pass through the second active layer 120, and pass through the first conductivity-type semiconductor layer, which is an n-type electron injection layer. It is possible to move more effectively to the region of the first active layer 110 adjacent to 112, thereby increasing the effective light emitting area by making the hole distribution in the active layer more uniform, and consequently, excellent luminous efficiency can be provided when high current is injected. .

6, according to the embodiment, the mobility of holes in the quaternary Al _x Ga _y In _1-xy N quantum wall 115B in the first two quantum wall structures from the n-GaN layer side is relatively very high. Show big.

Therefore, according to the embodiment, it means that holes injected from the second conductivity-type semiconductor layer 116 as the p-layer into the active layer can be more effectively transported in the direction of the first conductivity-type semiconductor layer 112 as the n-layer within the active layer. do.

Next, as shown in FIG. 9, in the second embodiment, the first quantum wall 110B may include an A quantum wall 111B and a B quantum wall 112B from the first conductivity type semiconductor layer 112. , The A quantum wall 111B and the B quantum wall 112B are respectively a first Al _x Ga _y In _1-xy N quantum wall 115B and a second Al _x Ga _y In _1-xy N quantum wall 116B ) Can be included.

In an embodiment, the Al concentration or bandgap energy of the second Al _x Ga _y In _1-xy N quantum wall 116B is the Al concentration of the first Al _x Ga _y In _1-xy N quantum wall 115B or It may be lower than the bandgap energy.

Through this, considering that the hole injection efficiency decreases as the distance from the second conductivity-type semiconductor layer 116 decreases, the Al concentration or the bandgap energy of the Al _x Ga _y In _1-xy N quantum wall gradually increases. , It is possible to maximize the hole injection efficiency while minimizing the occurrence of defects due to differences in lattice constants.

Next, as shown in FIG. 10, in the third embodiment, the first quantum wall 110B may include a plurality of Al _x Ga _y In _1-xy N quantum walls 117B and 118B, and the Al _x Ga _y The thickness of the In _1-xy N quantum wall may decrease from the first conductivity type semiconductor layer 112 to the second conductivity type semiconductor layer 116.

For example, the first quantum wall 110B has a first Al _x Ga _y In _1-xy N quantum wall 117B and a second thickness W1 from the first conductivity type semiconductor layer 112. the thickness (W2) a second Al _x Ga _y in _1-xy N may comprise a quantum wall (118B), a second thickness (W2 of the second Al _x Ga _y in _1-xy N quantum wall (118B) of ) May be smaller than the first thickness W1 of the first Al _x Ga _y In _1-xy N quantum wall 117B, and at the same concentration, the energy level increases as the thickness decreases. In the embodiment, the thickness of the Al _x Ga _y In _1-xy N quantum wall is controlled to control the band gap energy level, and the distribution is minimized by controlling the thickness of the Al _x Ga _y In _1-xy N quantum wall to generate defects. The hole injection efficiency can be maximized while minimizing.

Next, as shown in FIG. 11, in the fourth embodiment, the first quantum wall 113B may include a third Al _x Ga _y In _1-xy N quantum wall 119B, and the third Al _x Ga _y The energy level between the In _1-xy N quantum wall 119B and the first GaN quantum wall 111B may gradually change. For example, an energy level between the third Al _x Ga _y In _1-xy N quantum wall 119B and the first GaN quantum wall 111B may be inclined.

According to the fourth embodiment, the energy level between the third Al _x Ga _y In _1-xy N quantum wall 119B and the first GaN quantum wall 111B gradually changes, thereby reducing lattice defects and improving lattice quality. As a result, the hole injection efficiency can be further increased, and the luminous intensity can be remarkably increased.

Next, as shown in FIG. 12, by forming an aluminum gallium-based nitride semiconductor layer 160 on the active layer 130, luminous efficiency may be increased through an electron blocking function.

Thereafter, the second conductivity-type semiconductor layer 116 may be formed of a semiconductor compound on the aluminum gallium-based nitride semiconductor layer 160.

The second conductivity type semiconductor layer 116 may include a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0≤x≤1, 0≤y≤1, 0≤x+y≤1). I can. When the second conductivity-type semiconductor layer 116 is a p-type semiconductor layer, the second conductivity-type dopant is a p-type dopant, and may include Mg, Zn, Ca, Sr, Ba, and the like.

In an embodiment, the first conductivity-type semiconductor layer 112 may be implemented as an n-type semiconductor layer, and the second conductivity-type semiconductor layer 116 may be implemented as a p-type semiconductor layer, but is not limited thereto.

In addition, a semiconductor, for example, an n-type semiconductor layer (not shown) having a polarity opposite to that of the second conductivity type may be formed on the second conductivity type semiconductor layer 116. Accordingly, the light emitting structure 150 may be implemented in any one of an n-p junction structure, a p-n junction structure, an n-p-n junction structure, and a p-n-p junction structure.

Thereafter, a light-transmitting electrode 170 is formed on the second conductivity type semiconductor layer 116.

For example, the light-transmitting electrode 170 may include an ohmic layer, and may be formed by stacking a single metal, a metal alloy, or a metal oxide in multiple layers so that hole injection can be efficiently performed.

For example, the light-transmitting electrode 170 is ITO (indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tin oxide), IAZO (indium aluminum zinc oxide), IGZO (indium gallium zinc oxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO Nitride), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), ZnO, IrOx, RuOx, NiO, RuOx/ITO, Ni/IrOx/Au, and Ni/IrOx/Au/ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt , Au, and may be formed to include at least one of Hf, but is not limited to these materials.

Next, as shown in FIG. 13, the light-transmitting electrode 170, the second conductivity-type semiconductor layer 116, the aluminum gallium-based nitride semiconductor layer 160, and the active layer 130 are exposed so that the first conductivity-type semiconductor layer 112 is exposed. Some of the can be removed.

Next, as shown in FIG. 14, a second electrode 152 is formed on the light-transmitting electrode 170 and a first electrode 151 is formed on the exposed first conductive semiconductor layer 112 to emit light according to the embodiment. Devices can be formed.

According to the light emitting device and the manufacturing method of the light emitting device according to the embodiment, the effective light emitting area can be increased by making the hole distribution uniform in the active layer, and excellent luminous efficiency can be provided when high current is injected.

15 is a diagram illustrating a light emitting device package in which a light emitting device is installed according to embodiments.

The light emitting device package according to the embodiment is installed on the package body portion 205, the third electrode layer 213 and the fourth electrode layer 214 installed on the package body portion 205, and the package body portion 205 A light emitting device 100 electrically connected to the third and fourth electrode layers 213 and 214, and a molding member 230 surrounding the light emitting device 100 are included.

The third electrode layer 213 and the fourth electrode layer 214 are electrically separated from each other and serve to provide power to the light-emitting element 100. In addition, the third electrode layer 213 and the fourth electrode layer 214 may serve to increase light efficiency by reflecting light generated from the light emitting device 100, and It can also play a role in discharging heat to the outside.

The light emitting device 100 may be electrically connected to the third electrode layer 213 and/or the fourth electrode layer 214 by any one of a wire method, a flip chip method, or a die bonding method.

16 is an exploded perspective view of a lighting system according to an embodiment.

The lighting device according to the embodiment may include a cover 2100, a light source module 2200, a radiator 2400, a power supply unit 2600, an inner case 2700, and a socket 2800. In addition, the lighting device according to the embodiment may further include one or more of a member 2300 and a holder 2500. The light source module 2200 may include a light emitting device or a light emitting device package according to the embodiment.

The light source module 2200 may include a light source unit 2210, a connection plate 2230, and a connector 2250. The member 2300 is disposed on an upper surface of the radiator 2400 and has guide grooves 2310 into which a plurality of light source units 2210 and a connector 2250 are inserted.

The holder 2500 blocks the receiving groove 2719 of the insulating part 2710 of the inner case 2700. Accordingly, the power supply unit 2600 accommodated in the insulating unit 2710 of the inner case 2700 is sealed. The holder 2500 has a guide protrusion 2510.

The power supply unit 2600 may include a protrusion 2610, a guide portion 2630, a base 2650, and an extension 2670. The inner case 2700 may include a molding unit together with the power supply unit 2600 therein. The molding part is a part where the molding liquid is solidified, and allows the power supply part 2600 to be fixed inside the inner case 2700.

Features, structures, effects, and the like described in the embodiments above are included in at least one embodiment, and are not necessarily limited to only one embodiment. Further, the features, structures, effects, and the like illustrated in each embodiment may be combined or modified for other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be interpreted as being included in the scope of the embodiments.

Although the embodiments have been described above, these are only examples and are not intended to limit the embodiments, and those of ordinary skill in the field to which the embodiments belong are not departing from the essential characteristics of the embodiments. It will be seen that branch transformation and application are possible. For example, each component specifically shown in the embodiment can be modified and implemented. And differences related to these modifications and applications should be construed as being included in the scope of the embodiments set in the appended claims.

The first conductivity type semiconductor layer 112, the first quantum wall 110B, the first active layer 110,
The second quantum wall 115B, the second active layer 120, the second conductivity type semiconductor layer 116,
The first Al _x Ga _y In _1-xy N quantum wall (115B)

Claims (12)

A first conductivity type semiconductor layer;
A first active layer including a plurality of first quantum walls having a first band gap energy on the first conductivity type semiconductor layer;
A second active layer having a plurality of second quantum walls having a second band gap energy smaller than the first band gap energy on the first active layer; And
Including; a second conductivity type semiconductor layer on the second active layer,
The first active layer is disposed adjacent to the first conductivity type semiconductor layer compared to the second active layer,
Each of the plurality of first quantum walls of the first active layer,
A plurality of first GaN quantum walls; And
Including a first Al _x Ga _y In _1-xy N quantum wall (where 0<x≤1, 0≤y≤1) disposed between the plurality of first GaN quantum walls,
The second quantum wall includes a second GaN quantum wall,
The band gap energy of the first Al _x Ga _y In _1-xy N quantum wall included in each of the plurality of first quantum walls is a band gap energy of the plurality of first GaN quantum walls and the second GaN quantum wall Greater than,
The band gap energy of the first Al _x Ga _y In _1-xy N quantum wall has a larger band gap energy as it is included in the first quantum wall adjacent to the first conductivity type semiconductor layer, and the second conductivity type semiconductor A light emitting device having a smaller band gap energy as it is included in the first quantum wall adjacent to the layer. The method of claim 1,
The first conductivity-type semiconductor layer is an n-type semiconductor layer. The method of claim 1,
The light emitting device is a blue light emitting device,
The thickness of the first Al _x Ga _y In _1-xy N quantum wall is 0.5 nm to 5 nm,
A light emitting device having an Al content of 1% to 25% in the first Al _x Ga _y In _1-xy N quantum wall. delete delete delete The method of claim 1,
The thickness of the first Al _x Ga _y In _1-xy N quantum wall is thinner as it is included in the first quantum wall adjacent to the first conductivity type semiconductor layer, and the first quantum wall adjacent to the second conductivity type semiconductor layer The thicker the light-emitting device is included in the wall. delete delete delete delete An illumination system comprising a light-emitting unit comprising the light-emitting element according to any one of claims 1 to 3 and 7.

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