KR20160024420A - Light emitting device and lighting system - Google Patents

Abstract

An embodiment relates to a light emitting device, a method for manufacturing the light emitting device, a light emitting device package, and a lighting system. According to an embodiment, the light-emitting device comprises: a first-conductivity-type semiconductor layer; an active layer on the first-conductivity-type semiconductor layer; an AlxGayIn(1-x-y)N layer (0<x<=1, 0<=y<=1)(122) on the active layer; an undoped AlpGa(1-p)N layer (0<=p<1) (124) on the AlxGayIn(1-x-y)N layer; and a second-conductivity-type semiconductor layer on the undoped AlpGa(1-p)N layer.

Description

[0001] LIGHT EMITTING DEVICE AND LIGHTING SYSTEM [0002]

Embodiments relate to a light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system.

A light emitting device can be produced by combining p-n junction diodes having the characteristic that electric energy is converted into light energy by elements of Group III and Group V on the periodic table. LEDs can be implemented in various colors by controlling the composition ratio of compound semiconductors.

When a forward voltage is applied to a light emitting device, the electrons in the n-layer and the holes in the p-layer are coupled to emit energy corresponding to the energy gap between the conduction band and the valance band. It emits mainly in the form of heat or light, and emits in the form of light.

For example, nitride semiconductors have received great interest in the development of optical devices and high power electronic devices due to their high thermal stability and wide bandgap energy. Particularly, blue light emitting devices, green light emitting devices, ultraviolet (UV) light emitting devices, and the like using nitride semiconductors have been commercialized and widely used.

In the light emitting device according to the related art, the active layer, which is a light emitting layer, is formed by repetitively laminating a quantum well having a small energy band gap and a quantum wall having a large energy band gap, and electrons injected from the n layer and holes injected from the p- And emits light.

On the other hand, the light emitting device of the conventional structure has a problem in that the luminous efficiency is lowered when the amount of injected current is increased. This is due to the low electron injection efficiency and hole injection efficiency in the light emitting layer.

Specifically, the hole has a relatively large effective mass relative to the electron, low mobility, and high activation energy of the p-type dopant, resulting in a low hole concentration in the p-layer.

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

As a result, when electrons and holes are injected into the light-emitting layer, electrons move effectively in the p-layer direction in the light-emitting layer, while holes do not effectively move in the light-emitting layer toward the n- layer.

As a result, electrons and holes mainly meet each other in the light-emitting layer adjacent to the p-layer and emit light mainly. This charge asymmetry eventually reduces the number of quantum wells that are substantially involved in luminescence, thereby reducing the effective luminescent area.

This decrease in the effective luminescent area increases the electron overflow from the light emitting layer to the p-layer, and causes a problem of non-luminescent recombination in the light emitting layer, resulting in a decrease in the light emitting efficiency.

Therefore, in order to solve the problem of lowering the luminous efficiency occurring when the injection current is increased, it is necessary to effectively transfer the holes from the p- layer to the n- layer in the light emitting layer in order to provide the high efficiency nitride semiconductor light emitting device, Therefore, it is required to develop a technique that allows all quantum wells of the light emitting layer to substantially participate in light emission.

Embodiments provide a high-efficiency nitride semiconductor light-emitting device capable of solving the problem of lowering the luminous efficiency occurring when an injection current is increased, a method of manufacturing the same, a light-emitting device package, and a lighting system.

The light emitting device according to the embodiment includes a first conductive semiconductor layer 112; An active layer 114 on the first conductive semiconductor layer 112; An Al _x Ga _y In _{1 -x- y} N layer (0 <x? 1, 0? _Y? 1) 122 on the active layer 114; On the Al _x Ga _y In _{1 -x- y} N layer 122, an undoped Al _p Ga _{1 - p} N layer (0? _P <1) (124); And a second conductivity type semiconductor layer 116 on the un _{- doped} Al _p Ga _{1 - p} N layer 124.

The illumination system according to the embodiment may include a light emitting unit having the light emitting element.

The embodiments can provide a high-efficiency nitride semiconductor light emitting device capable of solving the problem of lowering the luminous efficiency occurring when an injection current is increased, a method of manufacturing the same, a light emitting device package, and an illumination system.

For example, according to the light emitting device according to the embodiment, the current spreading can be improved, and the yield and the thermal characteristics can be improved.

Further, according to the embodiment, the hole mobility in the un _{- doped} Al _p Ga _{1 - p} N layer region is improved and the luminous intensity Po can be improved.

1 is a cross-sectional view of a light emitting device according to an embodiment.
2 is a first energy bandgap diagram of a light emitting device according to an embodiment.
3 is a second energy bandgap diagram of a light emitting device according to an embodiment.
4A is a composition data of a light emitting device according to an embodiment.
4B is an enlarged view of the composition data portion of the light emitting device according to the embodiment.
5A is a graph illustrating a comparison result of the second internal luminescence efficiency according to the injection current of the light emitting device according to the embodiment.
FIG. 5B is a graph illustrating the third internal light emission efficiency and the comparison example data according to the injection current of the light emitting device according to the embodiment.
6 to 8 are diagrams showing a manufacturing process of the light emitting device according to the embodiment.
9 is a sectional view of a light emitting device package according to an embodiment.
10 is an exploded perspective view of a lighting apparatus according to an embodiment.

In the description of the embodiments, each layer (film), region, pattern or structure is referred to as being "on" or "under" the substrate, each layer (film) Quot; on "and" under "are intended to include both" directly "or" indirectly " do. Also, the criteria for top, bottom, or bottom of each layer will be described with reference to the drawings.

(Example)

1 is a cross-sectional view of a light emitting device 100 according to an embodiment.

The light emitting device 100 according to the embodiment includes a first conductive semiconductor layer 112, an active layer 114 on the first conductive semiconductor layer 112, and a second conductive semiconductor Layer 116 as shown in FIG. The first conductive semiconductor layer 112, the active layer 114, and the second conductive semiconductor layer 116 may be referred to as a light emitting structure 110.

In the embodiment, an Al _x Ga _y In _1-xy N layer (0 <x? 1, 0? _Y? 1) 122 is formed between the active layer 114 and the second conductive semiconductor layer 116 And the luminous efficiency can be increased through the electron cutoff function.

The embodiment may include the light-transmitting electrode 130 on the second conductive type semiconductor layer 116 and may be electrically connected to the second conductive type semiconductor layer 116 and the first conductive type semiconductor layer 112, respectively A second electrode 152, and a first electrode 151.

As shown in FIG. 1, the embodiment may be a horizontal type light emitting device in which a light emitting structure 110 is disposed on a substrate 102, but the present invention is not limited thereto, and may be applied to a vertical type light emitting device or a flip chip light emitting device.

2 is a first energy bandgap diagram of the light emitting device according to the embodiment.

An embodiment of the present invention provides a high-efficiency nitride semiconductor light-emitting device capable of solving the problem of lowering the luminous efficiency caused by an increase in injection current.

To this end, the embodiment is characterized in that a layer of undoped Al _p Ga _{1 - p} N (where 0 _{p & lt; 1} ) is formed between the Al _x Ga _y In _{1 -x- y} N layer 122 and the second conductive semiconductor layer 116 ) &Lt; / RTI &gt;

The second conductivity type semiconductor layer 116 may include a second conductivity type semiconductor layer 116a having a first concentration and a second concentration higher than the first concentration on the second conductivity type semiconductor layer 116a having the first concentration. Of the second conductivity type semiconductor layer 116b.

As shown in FIG. 2, the undoped Al _p Ga _{1 - p} N layer may be an undoped GaN layer 124, and the second conductivity type semiconductor layer 116 may be a p-type GaN layer.

For example, the second conductivity type semiconductor layer 116 may include a p-type GaN layer 116a having a first concentration and a p-type GaN layer 116a having a first concentration on the undoped GaN layer 124, Type GaN layer 116b having a second concentration higher than the first concentration.

3 is a second energy band gap diagram of the light emitting device according to the embodiment.

In another embodiment, the un _{- doped} Al _p Ga _{1 - p} N layer may be an undoped AlGaN-based layer 125 and the second conductive semiconductor layer 116 may be a p-type AlGaN-based layer.

For example, as shown in FIG. 3, the second conductivity type semiconductor layer 116 may include a p-type AlGaN series layer 117a of a first concentration and a p-type AlGaN series layer 117a of the first concentration on the undoped AlGaN series layer 125, Type AlGaN layer 117b having a second concentration higher than the first concentration on the AlGaN-based layer 117a.

2 or 3, an Al _x Ga _y In _{1 -x- y} N layer (where 0 &lt; x &lt; _{= 1} , 0 &lt; / = y &lt; / = 1) 122 to increase the luminous efficiency through the electron blocking function.

At this time, the thickness of the Al _x Ga _y In _{1 -x- y} N layer (where 0 <x? 1, 0? _Y? 1) 122 may be about 10 nm to about 50 nm. More specifically, the thickness of the Al _x Ga _y In _{1 -x- y} N layer (where 0 <x? 1, 0? _Y? 1) 122 may be 15 nm to 30 nm, but is not limited thereto.

When the thickness of the Al _x Ga _y In _{1 -x- y} N layer (where 0 <x? 1, 0? _Y? 1) 122 is less than 10 nm, the electron blocking effect is reduced, And the yield may be lowered. When the thickness of the Al _x Ga _y In _{1 -x- y} N layer (where 0 <x? 1, 0? _Y? 1) 122 is more than 50 nm, Hole injection is difficult to occur and there is a possibility that the operation voltage VF3 rises and the light intensity Po decreases.

FIG. 4A is a composition data of the light emitting device according to the embodiment, and FIG. 4B is an enlarged view of the composition data portion P of the light emitting device according to the embodiment.

For example, as illustrated in FIG. 2, the embodiment is characterized in that the un _{- doped} Al _p Ga _{1 - p} N layer (where 0? _P <1) 124 and the undoped Al _p Ga _{1 -p} N Lt; = p &lt; 1) layer. In FIG. 4, the case where the undoped Al _p Ga _{1 - p} N layer (where 0? _P <1) 124 is the GaN layer 124 is described as an example, but the embodiment is not limited thereto.

4, the second conductivity type semiconductor layer 116 may be a p-type GaN layer, but the present invention is not limited thereto. The doping concentration of the p-type dopant may be 1 x 10 ¹⁸ to 1 x 10 ²² atoms / cm 3 ³ ).

For example, the doping concentration of the p-type dopant in the p-type GaN layer 116a of the first concentration may be 1 x 10 ¹⁸ to 8 x 10 ¹⁹ (atoms / cm ³ ). When the doping concentration of the p-type dopant in the p-type GaN layer 116a of the first concentration is less than 1 x 10 ^{18, the} hole concentration may decrease and when the doping concentration exceeds 8 x 10 ¹⁹ , the surface morphology or the quality deteriorates Which may cause a decrease in the hole mobility caused by the magnetic field.

In addition, the doping concentration of the p-type dopant in the p-type GaN layer 116b of the second concentration may be 1x10 ²⁰ to 1x10 ²² (atoms / cm ³ ), but is not limited thereto.

According to the light emitting device according to the embodiment, the _un -doped Al _p Ga _{1 - p} N layer 124 is formed between the Al _x Ga _y In _{1 -x- y} N layer 122 and the second conductivity type semiconductor layer 116 The current spreading due to hole spreading in the region of the undoped Al _p Ga _{1 - p} N layer 124 becomes smooth, and the yield and thermal characteristics can be improved.

According to the embodiment, the hole mobility in the region of the undoped Al _p Ga _{1 - p} N layer 124 is improved, and the luminous intensity Po is improved by about 10 mW or more in a high injection current region of 500 mA or more.

Accordingly, embodiments can provide a high efficiency nitride semiconductor light emitting device, a method of manufacturing the same, a light emitting device package, and an illumination system capable of solving the problem of a decrease in luminous efficiency occurring when an injection current is increased.

FIG. 5A is a graph showing the second internal light emitting efficiency E2 and the comparison data E1 according to the injection current of the light emitting device according to the embodiment. FIG. 5B is a graph showing the third internal light emitting efficiency E3) and the comparison data E1.

The _{Al x Ga y In 1 -x- y} N layer (where, 0 <x≤1, 0≤y≤1) ( 122) later, the prompt undoped Al _p Ga _{1 - p} N layer 124 and the first The total thickness of the second conductivity type semiconductor layer 116a and the second concentration type second conductivity type semiconductor layer 116b may be about 40 nm to about 150 nm to improve the hole injection efficiency and crystal quality, And more particularly from about 50 nm to about 100 nm.

When the total thickness of the un-doped Al _p Ga _{1 - p} N layer 124, the first concentration of the second conductivity type semiconductor layer 116a, and the second concentration of the second conductivity type semiconductor layer 116b is less than 40 nm, Hole concentration, and when the total thickness exceeds 150 nm, the crystal quality may deteriorate and light loss may occur due to light absorption by p-GaN.

The thickness of the second conductivity type semiconductor layer 116b may be about 10 nm to about 20 nm. If the thickness of the second conductivity type semiconductor layer 116b is less than 10 nm, hole concentration may be deteriorated. If the thickness is more than 20 nm , Light loss may occur due to a decrease in quality and light absorption by the second conductivity type semiconductor layer 116b at the second concentration.

When the second conductivity type semiconductor layer 116b having a high concentration is formed thicker than 20 nm, in order to form the second conductivity type semiconductor layer 116b of the second concentration, the p-type dopant is doped at a high concentration Point defects and dislocations by doping can cause light absorption.

The sentence prompt Al _p Ga _{1 - p} N layer 124 and the second conductivity type wherein the thickness sum of the semiconductor layer (116a) is sentenced soft Al _p Ga ₁ of the first concentration _{- p} N layer 124, the ratio occupied by the Can be about 50% or more.

For example, the thickness of the un _{- doped} Al _p Ga _{1 - p} N layer 124 may be 1.0 or more of the thickness of the second conductivity type semiconductor layer 116a of the first concentration.

When the thickness of the undoped Al _p Ga _{1 - p} N layer 124 is less than 1.0 as compared with the thickness of the second conductivity type semiconductor layer 116a of the first concentration, current spreading is disadvantageous, The internal luminescence efficiency may be drastically decreased to deteriorate droop characteristics. Droop characteristics may deteriorate at high currents of about 500 mA or more.

For example, when the thickness of the un _{- doped} Al _p Ga _{1 - p} N layer 124 is 1.0 to 1.5 with respect to the thickness of the second conductivity type semiconductor layer 116a of the first concentration, the droop characteristics Can be remarkably improved.

If the thickness ratio of both is less than 1.0, the effect of the current spreading may not be properly shown because the undoped Al _p Ga _{1 - p} N layer 124 is too thin. If the thickness ratio exceeds 1.5, the hole injection ) May not be properly performed, and the droop characteristic may be deteriorated.

5A is a graph showing the relationship between the thickness ratio (former / latter) of the un-doped Al _p Ga _{1 - p} N layer 124 and the first concentration of the second conductivity type semiconductor layer 116a in Comparative Example E1 being 0.75 And the second internal luminous efficiency E2 is droop curve data when the thickness ratio is 1.0.

As shown in Figure 5a, reduce symptoms of Comparative Example (E1) of the first embodiment the second internal luminescence efficiency (E2) than the greater the 500nmA over high current this is lowered markedly, according to the embodiment greater the high current sentence prompt Al _p Ga _{1 the} internal light emission efficiency can be increased by increasing the current spreading and the hole injection efficiency by the _{- p} N layer 124.

5B shows a case where the thickness ratio of the comparative example E1 is 0.75 and the third internal luminous efficiency E3 is the droop curve data when the thickness ratio is 1.25 as shown in FIG. 5A.

FIG. 5B also shows that the decrease in the third internal luminous efficiency E3 of the second embodiment is significantly lower than that of the comparative example E1 as the current becomes higher than 500 nmA.

The embodiment can provide a high-efficiency nitride semiconductor light-emitting device capable of solving the problem of lowering the luminous efficiency occurring when the injection current is increased.

For example, according to the light emitting device according to the embodiment, the current spreading can be improved, and the yield and the thermal characteristics can be improved.

Further, according to the embodiment, the hole mobility in the un _{- doped} Al _p Ga _{1 - p} N layer region is improved and the luminous intensity Po can be improved.

Hereinafter, a method of manufacturing a light emitting device according to an embodiment will be described with reference to FIGS. 6 to 8, and the technical features of the embodiments will be described in detail.

First, the substrate 102 may be prepared as a growth substrate as shown in FIG. 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 is a sapphire (Al ₂ O _3), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, or Ga ₂ 0 ₃ May be used. A concave-convex structure may be formed on the substrate 102 to improve light extraction efficiency, but the present invention is not limited thereto.

At this time, a buffer layer (not shown) may be formed on the substrate 102. The buffer layer may mitigate the lattice mismatch between the material of the light emitting structure 110 to be formed and the substrate 102 and the material of the buffer layer may be a group III-V compound semiconductor such as GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN.

Next, a light emitting structure 110 including a first conductive semiconductor layer 112, an active layer 114, and a second conductive semiconductor layer 116 may be formed on the first substrate 102.

The first conductive semiconductor layer 112 may be formed of a semiconductor compound. Group 3-Group 5, Group 2-Group 6, and the like, and the first conductive type dopant may be doped. When the first conductive semiconductor layer 112 is an n-type semiconductor layer, the first conductive dopant may include Si, Ge, Sn, Se, and Te as an n-type dopant.

The first conductive semiconductor layer 112 may include a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + .

The first conductive 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 and InP.

The active layer 114 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, the active layer 114 may be formed with a multiple quantum well structure by injecting trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) But is not limited thereto.

The active layer 114 may have a quantum well 114W / quantum wall 114B structure as shown in FIG. For example, the active layer 114 may include one or more of AlInGaN / AlGaN, AlInGaN / GaN, InGaN / InGaN, InGaN / AlGaN, InGaN / AlGaN, InAlGaN / GaN, GaAs / AlGaAs, InGaAs / AlGaAs, InGaP / AlGaP. However, the present invention is not limited thereto. The active layer 114 may emit ultraviolet (UV) light, but the present invention is not limited thereto.

Hereinafter, the technical features of the embodiment will be described in more detail with reference to FIG. 2 or FIG.

In the embodiment, an Al _x Ga _y In _{1 -x- y} N layer (0 <x? 1, 0? _Y? 1) 122 is formed on the active layer 114 to form electron blocking and / The light emitting efficiency can be improved by acting as cladding (MQW cladding) of the active layer.

The thickness of the Al _x Ga _y In _{1 -x- y} N layer (where 0 <x? 1, 0? _Y? 1) 122 may be about 10 nm to about 50 nm. More specifically, the thickness of the Al _x Ga _y In _{1 -x- y} N layer (where 0 <x? 1, 0? _Y? 1) 122 may be 15 nm to 30 nm, but is not limited thereto.

When the thickness of the Al _x Ga _y In _{1 -x- y} N layer (where 0 <x? 1, 0? _Y? 1) 122 is less than 10 nm, the electron blocking effect is reduced, And the yield may be lowered. When the thickness of the Al _x Ga _y In _{1 -x- y} N layer (where 0 <x? 1, 0? _Y? 1) 122 is more than 50 nm, Hole injection is difficult to occur and there is a possibility that the operation voltage VF3 rises and the light intensity Po decreases.

An embodiment of the present invention provides a high-efficiency nitride semiconductor light-emitting device capable of solving the problem of a decrease in luminous efficiency occurring when an injection current is increased. The Al _x Ga _y In _{1 -x- y} N layer 122 is provided with an undoped Al _p Ga _1- pN layer (where 0? _p &lt; 1) 124 may be formed.

Thereafter, the second conductivity type semiconductor layer 116 may be formed on the un _{- doped} Al _p Ga _{1 - p} N layer (where 0? _P <1) 124.

The second conductivity type semiconductor layer 116 may include a second conductivity type semiconductor layer 116a having a first concentration and a second concentration higher than the first concentration on the second conductivity type semiconductor layer 116a having the first concentration. Of the second conductivity type semiconductor layer 116b.

For example, as illustrated in FIG. 2, the embodiment is characterized in that the un _{- doped} Al _p Ga _{1 - p} N layer (where 0? _P <1) 124 and the undoped Al _p Ga _{1 -p} N Lt; = p &lt; 1) layer. In FIG. 4, the case where the undoped Al _p Ga _{1 - p} N layer (where 0? _P <1) 124 is the GaN layer 124 is described as an example, but the embodiment is not limited thereto.

In addition, the second conductive type semiconductor layer 116 in the embodiment as shown in Figure 4, the p-type GaN may be a layer, not limited to this, the doping concentration of the p-type dopant is 1x101 ¹⁸ to 1x10 ²² (atoms / cm ³ ).

For example, the doping concentration of the p-type dopant in the p-type GaN layer 116a of the first concentration may be 1 x 10 ¹⁸ to 8 x 10 ¹⁹ (atoms / cm ³ ). When the doping concentration of the p-type dopant in the p-type GaN layer 116a of the first concentration is less than 1 x 10 ^{18, the} hole concentration may decrease and when the doping concentration exceeds 8 x 10 ¹⁹ , the surface morphology or the quality deteriorates Which may cause a decrease in the hole mobility caused by the magnetic field.

In addition, the doping concentration of the p-type dopant in the p-type GaN layer 116b of the second concentration may be 1x10 ²⁰ to 1x10 ²² (atoms / cm ³ ), but is not limited thereto.

Alternatively, as in FIG. 3, in another embodiment, the un-Al _Pt Ga _{1 - p} N layer may be an undoped AlGaN-based layer 125 and the second conductive semiconductor layer 116 may be a p-type AlGaN-based layer .

For example, the second conductivity type semiconductor layer 116 may include a p-type AlGaN series layer 117a of a first concentration and a p-type AlGaN series layer 117a of the first concentration on the undoped AlGaN series layer 125 Type AlGaN layer 117b having a second concentration higher than the first concentration may be formed on the second p-type AlGaN layer 117a.

According to the light emitting device according to the embodiment, the _un -doped Al _p Ga _{1 - p} N layer 124 is formed between the Al _x Ga _y In _{1 -x- y} N layer 122 and the second conductivity type semiconductor layer 116 The current spreading due to hole spreading in the region of the undoped Al _p Ga _{1 - p} N layer 124 becomes smooth, and the yield and thermal characteristics can be improved.

According to the embodiment, the hole mobility in the region of the undoped Al _p Ga _{1 - p} N layer 124 is improved, and the luminous intensity Po is improved by about 10 mW or more in a high injection current region of 500 mA or more.

In addition, the _{Al x Ga y In 1 -x- y} N layer (where, 0 <x≤1, 0≤y≤1) ( 122) later, the prompt undoped Al _p Ga ₁ in Example _{- p} N layer (124 ) And the total thickness of the second conductivity type semiconductor layer 116a of the first concentration and the second conductivity type semiconductor layer 116b of the second concentration are about 40 nm to about 150 nm, the hole injection efficiency is increased and the crystal quality is improved And, more particularly, from about 50 nm to about 100 nm.

When the total thickness of the un-doped Al _p Ga _{1 - p} N layer 124, the first concentration of the second conductivity type semiconductor layer 116a, and the second concentration of the second conductivity type semiconductor layer 116b is less than 40 nm, Hole concentration, and when the total thickness exceeds 150 nm, the crystal quality may deteriorate and light loss may occur due to light absorption by p-GaN.

The thickness of the second conductivity type semiconductor layer 116b may be about 10 nm to about 20 nm. If the thickness of the second conductivity type semiconductor layer 116b is less than 10 nm, hole concentration may be deteriorated. If the thickness is more than 20 nm The optical loss may occur due to the degradation of the quality and the light absorption by the p + -GaN itself.

When the second conductivity type semiconductor layer 116b having a high concentration is formed thicker than 20 nm, in order to form the second conductivity type semiconductor layer 116b of the second concentration, the p-type dopant is doped at a high concentration Point defects and dislocations by doping can cause light absorption.

The sentence prompt Al _p Ga _{1 - p} N layer 124 and the second conductivity type wherein the thickness sum of the semiconductor layer (116a) is sentenced soft Al _p Ga ₁ of the first concentration _{- p} N layer 124, the ratio occupied by the Can be about 50% or more. For example, the thickness of the un _{- doped} Al _p Ga _{1 - p} N layer 124 may be 1.0 or more of the thickness of the second conductivity type semiconductor layer 116a of the first concentration.

When the thickness of the undoped Al _p Ga _{1 - p} N layer 124 is less than 1.0 as compared with the thickness of the second conductivity type semiconductor layer 116a of the first concentration, current spreading is disadvantageous, The internal luminescence efficiency may be drastically decreased to deteriorate droop characteristics. Droop characteristics may deteriorate at high currents of about 500 mA or more.

For example, when the thickness of the un _{- doped} Al _p Ga _{1 - p} N layer 124 is 1.0 to 1.5 with respect to the thickness of the second conductivity type semiconductor layer 116a of the first concentration, the droop characteristics Can be remarkably improved. If the ratio of the thicknesses of both layers is less than 1.0, the effect of current spreading may not be exhibited due to the fact that the un _{- doped} Al _p Ga _{1 - p} N layer is too thin. If the thickness ratio exceeds 1.5, hole injection Can not be achieved.

In an embodiment, the first conductive semiconductor layer 112 may be an n-type semiconductor layer, and the second conductive semiconductor layer 116 may be a p-type semiconductor layer.

Also, on the second conductive semiconductor layer 116, a semiconductor (e.g., an n-type semiconductor) (not shown) having a polarity opposite to that of the second conductive type may be formed. Accordingly, the light emitting structure 110 may have 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 130 is formed on the second conductive type semiconductor layer 116.

For example, the light-transmitting electrode 130 may include an ohmic layer, and may be formed by laminating a single metal, a metal alloy, a metal oxide, or the like so as to efficiently inject holes.

For example, the transmissive electrode 130 may be formed of a material selected from the group consisting of ITO (indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tin oxide), IAZO (indium aluminum zinc oxide), IGZO (ZnO), indium gallium tin oxide (AZO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IZON nitride, AGZO Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Ni, IrOx / Au, and Ni / IrOx / , Au, and Hf, and is not limited to such a material.

Next, as shown in FIG. 7, a transparent electrode 130, a second conductive semiconductor layer 116, an undoped Al _p Ga _{1 - p} N layer 124, an Al _x Ga _y In _{1 -x- y} N layer 122 and a part of the active layer 114 can be removed.

Next, as shown in FIG. 8, a second electrode 152 is formed on the transparent electrode 130, and a first electrode 151 is formed on the exposed first conductive semiconductor layer 112, Device can be formed.

The embodiments can provide a high-efficiency nitride semiconductor light emitting device capable of solving the problem of lowering the luminous efficiency occurring when an injection current is increased, a method of manufacturing the same, a light emitting device package, and an illumination system.

For example, according to the light emitting device according to the embodiment, the current spreading can be improved, and the yield and the thermal characteristics can be improved.

Further, according to the embodiment, the hole mobility in the un _{- doped} Al _p Ga _{1 - p} N layer region is improved and the luminous intensity Po can be improved.

9 is a view illustrating a light emitting device package having the light emitting device according to the embodiments.

The light emitting device package according to the embodiment includes a package body 205, a third electrode layer 213 and a fourth electrode layer 214 provided on the package body 205, A light emitting device 100 electrically connected to the third electrode layer 213 and the fourth electrode layer 214 and a molding member 230 surrounding the light emitting device 100 are included. The molding member 230 may include a phosphor 232.

The third electrode layer 213 and the fourth electrode layer 214 are electrically isolated from each other and provide power to the light emitting device 100. The third electrode layer 213 and the fourth electrode layer 214 may function to increase light efficiency by reflecting the light generated from the light emitting device 100, And may serve to discharge 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 a wire, flip chip, or die bonding method.

10 is an exploded perspective view of an illumination system according to an embodiment.

The lighting apparatus according to the embodiment may include a cover 2100, a light source module 2200, a heat discharger 2400, a power supply unit 2600, an inner case 2700, and a socket 2800. Further, the illumination device according to the embodiment may further include at least one of the member 2300 and the 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 the upper surface of the heat discharging body 2400 and has guide grooves 2310 through which the plurality of light source portions 2210 and the connector 2250 are inserted.

The holder 2500 blocks the receiving groove 2719 of the insulating portion 2710 of the inner case 2700. Therefore, the power supply unit 2600 housed in the insulating portion 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 2630, a base 2650, and an extension 2670. The inner case 2700 may include a molding part together with the power supply part 2600. The molding part is a hardened portion of the molding liquid so that the power supply unit 2600 can be fixed inside the inner case 2700.

The features, structures, effects and the like described in the embodiments are included in at least one embodiment and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects and the like illustrated in the embodiments can be combined and modified by other persons skilled in the art to which the embodiments belong. Accordingly, the contents of such combinations and modifications should be construed as being included in the scope of the embodiments.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. It can be seen that the modification and application of branches are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

The first conductive semiconductor layer 112, the active layer 114,
Al _x Ga _y In _{1 -x- y} N layers (where 0 <x? 1, 0? _Y? 1) (122)
Undoped Al _p Ga _{1 - p} N layer (where 0? _P <1) (124),
The second conductivity type semiconductor layer 116, the first conductivity type second conductivity type semiconductor layer 116a,
The second conductivity type semiconductor layer 116b of the second concentration,

Claims (10)

A first conductive semiconductor layer;
An active layer on the first conductive semiconductor layer;
An Al _x Ga _y In _{1 -x- y} N layer (0 < x &lt; = 1, 0 &lt; = y &lt; = 1) on the active layer;
An undoped Al _p Ga _{1 - p} N layer (0? _P <1) on the Al _x Ga _y In _{1 -x- y} N layer; And
And a second conductivity type semiconductor layer on the undoped Al _p Ga _{1 - p} N layer. The method according to claim 1,
The second conductivity type semiconductor layer
A second conductivity type semiconductor layer of a first concentration; And
And a second conductivity type semiconductor layer having a second concentration higher than the first concentration on the second conductivity type semiconductor layer of the first concentration. 3. The method of claim 2,
And the undoped Al _p Ga _{1 - p} N layer comprises an undoped GaN layer. The method of claim 3,
The second conductivity type semiconductor layer
A p-type GaN layer of a first concentration on the undoped GaN layer; And
And a p-type GaN layer of a second concentration higher than the first concentration on the p-type GaN layer of the first concentration. 3. The method of claim 2,
Wherein the undoped Al _p Ga _{1 - p} N layer comprises an undoped AlGaN-based layer. 6. The method of claim 5,
The second conductivity type semiconductor layer
A p-type AlGaN-based layer of a first concentration on the undoped AlGaN-based layer; And
And a p-type AlGaN-based layer of a second concentration higher than the first concentration on the p-type AlGaN-based layer of the first concentration. 3. The method of claim 2,
Wherein the thickness of the undoped Al _p Ga _{1 - p} N layer is 1.0 or more of the thickness of the second conductivity type semiconductor layer of the first concentration. The method according to claim 1,
The active layer
A light emitting device that emits an ultraviolet (UV) wavelength. The method according to claim 1,
The Al _x Ga _y In _1-xy N layer (122) is formed to a thickness of 10 nm or more and 50 nm or less. An illumination system comprising a light-emitting unit comprising the light-emitting element according to any one of claims 1 to 9.

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