KR20130024151A - Light emitting device - Google Patents

Abstract

PURPOSE: A light emitting device is provided to maintain the barrier height of an electron barrier layer and to reduce a leakage current. CONSTITUTION: An active layer(114) includes a quantum well and a quantum wall. The active layer is formed on a first conductive semiconductor layer(112). An electron barrier layer(126) is formed on the active layer. A second conductive semiconductor layer(116) is formed on the electron barrier layer. The energy band gap of the electron barrier layer gradually increases from the active layer to the second conductive semiconductor layer.

Description

[0001] LIGHT EMITTING DEVICE [0002]

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

A light emitting device is a device that converts electrical energy into light energy, and for example, various colors can be realized by adjusting a composition ratio of a compound semiconductor.

The light emitting device according to the prior art has a multi-quantum well structure composed of an N-type GaN layer, an InGaN quantum well and GaN quantum walls on a sapphire substrate, a P-type GaN layer, and electrons and P-type supplied from the N-type GaN layer. Holes supplied from the GaN layer combine with each other in the active layer to emit light.

1 is an exemplary energy band diagram of a light emitting device according to the prior art.

According to the prior art, the wurtzite GaN-based quantum well structure grown in the (001) direction on the C axis has a large internal field due to spontaneous polarization and piezoelectric polarization. field).

This polarization phenomenon deforms the energy band structure of the quantum well (A1), resulting in the spatial separation of the wave function (electron and hole existence probability) of electrons and holes from each other. Failure to confine results in a significant reduction in the radiative recombination rate.

Piezoelectric polarization is caused by structural strain. The GaN-based LED structure is composed of a plurality of growth layers, and the characteristics of each layer are modified by the addition of Al and In.

Alloys of Al and In lead to inconsistencies in the lattice constant or thermal coefficient of each layer, resulting in structural strain. Thus, each of the layers is stressed with each other, which causes the polarization.

Due to the piezoelectric polarization, the wave function of the electron and the wave function of the hole are located opposite to each other in the quantum quantum well, so that the efficiency of electron recombination of electrons and holes is proportional to the overlapping area where the two wave functions overlap. As a result, the light emission recombination efficiency of electrons and holes is reduced, and the amount of light emitted is also reduced.

As such, electrons and holes that do not recombine cross the quantum barrier and electrons leak toward the p-side electrode, and holes leak toward the n-side electrode. This phenomenon is a typical weakness of the conventional GaN-based nitride semiconductor light emitting device. It is one of the problems (so-called "Droop phenomenon") that the luminous efficiency decreases at high current. Therefore, elimination of the piezoelectric polarization phenomenon due to the difference between the lattice constant and the coefficient of thermal expansion becomes an essential requirement for manufacturing a high output high efficiency light emitting device.

In addition, the internal field causes polarization (A2) between the last quantum barrier of the quantum well and the electron blocking layer (A2), which deforms the energy band structure, which is actually designed. The band shape of the electron blocking layer is modified. As a result, the height of the energy blocking barrier is reduced, which reduces the efficiency of the electron blocking, and furthermore, prevents the efficient injection of holes.

This is generally caused by the accumulation of positive charges at the interface due to the polarization difference between the electron blocking layer made of AlGaN and the quantum barrier made of GaN.

In addition, it is necessary to secure the reliability of the light emitting device in order to develop a high output, high efficiency light emitting device.

Embodiments provide an efficient light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system by reducing an internal field resulting from a polarization difference between a quantum wall and an electron blocking layer.

In addition, the embodiment is to provide a high-efficiency light emitting device, a method of manufacturing a light emitting device, a light emitting device package and an illumination system that can increase the internal quantum efficiency.

In addition, the embodiment is to provide a light emitting device, a method of manufacturing a light emitting device, a light emitting device package and an illumination system with improved reliability.

The light emitting device according to the embodiment includes a first conductivity type semiconductor layer; An active layer formed on the first conductivity type semiconductor layer including a quantum well and a quantum wall; An electron blocking layer on the active layer; And a second conductive semiconductor layer on the electron blocking layer, wherein an energy band gap of the electron blocking layer may increase in the direction of the second conductive semiconductor layer in the active layer.

According to the embodiment, it is possible to provide a high efficiency light emitting device, a manufacturing method of the light emitting device, a light emitting device package and an illumination system by reducing the internal field resulting from the polarization difference between the quantum wall and the electron blocking layer.

In addition, the embodiment can reduce the leakage current by effectively maintaining the barrier height of the electron blocking layer and increase the hole injection efficiency by reducing the barrier at the injection hole, thereby increasing the internal quantum efficiency. A light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system can be provided.

In addition, the embodiment can provide a light emitting device, a manufacturing method of the light emitting device, a light emitting device package and an illumination system with improved reliability.

1 is an exemplary energy band diagram of a light emitting device according to the prior art.
2 is a cross-sectional view of a light emitting device according to the embodiment.
3 is an energy band gap and polarized charge distribution according to Al and In compositions in the light emitting device according to the embodiment;
4 is an exemplary energy band diagram of a light emitting device according to an embodiment;
5 is an exemplary distribution of electrons at the time of high current injection in the light emitting device according to the embodiment.
6 is a view illustrating a hole distribution during high current injection in the light emitting device according to the embodiment.
7 is a view illustrating light output according to injection current in the light emitting device according to the embodiment;
8 is an exemplary diagram illustrating internal quantum efficiency according to injection current in a light emitting device according to an embodiment.
9 is a cross-sectional view of a light emitting device package according to the embodiment.
10 is a perspective view of a lighting unit according to an embodiment.
11 is a perspective view of a backlight unit according to an embodiment.

In the description of the embodiments, it is to be understood that each layer (film), area, pattern or structure may be referred to as being "on" or "under" the substrate, each layer 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.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. In addition, the size of each component does not necessarily reflect the actual size.

(Example)

2 is a cross-sectional view of a light emitting device 100 according to the embodiment.

The light emitting device 100 according to the embodiment includes a first conductive semiconductor layer 112, an active layer 114 formed on the first conductive semiconductor layer 112, including a quantum well and a quantum wall, and the active layer. An electron blocking layer 126 and a second conductivity type semiconductor layer 116 may be included on the electron blocking layer 126.

The first conductivity type semiconductor layer 112, the active layer 114, and the second conductivity type semiconductor layer 116 may form a light emitting structure 110.

The light emitting structure 110 may be formed on the substrate 105, and the substrate 105 may be formed of a material having excellent thermal conductivity. For example, the light emitting structure 110 may be a conductive substrate or an insulating substrate. For example, the substrate 105 is a sapphire (Al ₂ O _3), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, and Ga ₂ 0 ₃ May be used.

The first conductivity type semiconductor layer 112 may be formed of a semiconductor compound. It may be implemented as a compound semiconductor, such as Group 3-5, Group 2-6, and the first conductivity type dopant may be doped. When the first conductivity type semiconductor layer 112 is an N type semiconductor layer, the first conductivity type dopant may be Si type Ge, but may include Si, Ge, Sn, Se, Te, but is not limited thereto. 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 active layer 114 may include at least one of a single and multiple well structure, a single quantum well structure, a multi quantum well structure (MQW), a quantum-wire structure, or a quantum dot structure. Can be formed. The active layer 114 will be described later in detail.

The second conductivity type semiconductor layer 116 may be formed of a semiconductor compound. For example, the compound semiconductor may be implemented as a compound semiconductor such as Group 3-5, Group 2-6, and the second conductive dopant may be doped. For example, the composition formula of the second conductive semiconductor layer 116 is _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) It may include a semiconductor material having. When the second conductivity type semiconductor layer 116 is a P type semiconductor layer, the second conductivity type dopant may include Mg, Zn, Ca, Sr, Ba, or the like as a P type dopant.

In an exemplary 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, 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 conductive type may be formed on the second conductive type semiconductor layer 116. Accordingly, the light emitting structure 110 may be implemented as 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.

Embodiments provide a light emitting device having improved reliability, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system.

In an embodiment, in order to improve reliability, an active layer 114 is formed after forming a current spreading layer 122, an electron injection layer (not shown), and a strain control layer 124 on the first conductivity-type semiconductor layer 112. As a result, the reliability of the light emitting device can be improved to provide a high efficiency light emitting device.

The current spreading layer 122 is formed on the first conductivity type semiconductor layer 112. The current diffusion layer 122 may be an undoped gallium nitride layer, but is not limited thereto. The current spreading layer 122 may have a thickness of 50 nm to 200 nm, but is not limited thereto.

Thereafter, an electron injection layer (not shown) may be formed on the current spreading layer 122.

The electron injection layer (not shown) may be a first conductivity type gallium nitride layer. For example, the electron injection layer may be the electron injection efficiently by being doped at a concentration of the n-type doping element ^{6.0x10 18 atoms / cm 3 ~ 8.0x10} 18 atoms / cm 3.

In addition, the embodiment may form the strain control layer 124 on the electron injection layer (not shown). For example, the strain control layer 124 formed of In _y Al _x Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) / GaN may be formed on the electron injection layer.

The strain control layer 124 may effectively alleviate stresses that are odd due to lattice mismatch between the first conductivity-type semiconductor layer 112 and the active layer 114.

In addition, as the strain control layer 124 is repeatedly stacked in at least 6 cycles having a composition of 1 In _{x 1} GaN, 2 In _x 2 GaN, and the like, more electrons are collected at a lower energy level of the active layer 114, and as a result, As a result, the probability of recombination of electrons and holes may be increased, thereby improving luminous efficiency.

In an embodiment, an electron blocking layer (EBL) 126 is formed between the active layer 114 and the second conductive semiconductor layer 116 to serve as electron blocking and cladding of the active layer. By improving the luminous efficiency can be improved.

For example, the electron blocking layer 126 may be formed of an In _y Al _x Ga _(1-xy) N (0 ≦ _x ≦ 1,0 ≦ _y ≦ 1) based semiconductor. It may have a higher energy band gap than the energy band gap, and may be formed to a thickness of about 100 kPa to about 600 kPa, but is not limited thereto.

The electron blocking layer 126 may efficiently block electrons that overflow, and increase the injection efficiency of holes. For example, the electron blocking layer 126 may effectively block electrons that overflow due to Mg doping in a concentration range of about 10 ¹⁸ to 10 ²⁰ / cm ³ , and increase injection efficiency of holes.

According to the embodiment, it is possible to provide a high efficiency light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system, including a current diffusion layer, an electron injection layer, a strain control layer, or an electron blocking layer.

On the other hand, the embodiment is to provide a high efficiency light emitting device, a method of manufacturing a light emitting device, a light emitting device package and an illumination system by reducing the internal field resulting from the polarization difference between the quantum wall and the electron blocking layer.

In addition, the embodiment is to provide a high-efficiency light emitting device, a method of manufacturing a light emitting device, a light emitting device package and an illumination system that can increase the internal quantum efficiency.

3 is a distribution diagram of energy band gap and polarization charge according to Al and In compositions in the light emitting device according to the embodiment.

In the light emitting device according to the embodiment, the electron blocking layer (EBL) 126 may include a quaternary material including indium (In). For example, the electron blocking layer 126 may include In _y Al _x Ga _(1-xy) N (0 ≦ _x ≦ 1,0 ≦ _y ≦ 1).

The example calculated the energy band gap and the polarization charge amount of the quaternary In _y Al _x Ga _(1-xy) N material. Uihamyeo to the calculated result, each generally used as the electron blocking layer is an Al _{0 .17} Ga _{0 .83} N and both wall polarization jeonharyangneun between ^{GaN - 0.05 Cm -2, - 0.034} Cm - was calculated to be ^2, the polarization charge amount Due to the difference of the energy band will be deformed.

Therefore, in order to match the electron blocking layer with the amount of polarized charges in the quantum wall GaN, a modification of the quaternary tone is required. However, because the change in composition also changes the band gap, in order to maintain its role as an electron blocking layer, the band gap, which is the difference in energy level between the quantum well and the quantum wall, must not be reduced. The change in should be taken into account.

In an embodiment, the composition (C) may be used on a line in which the polarization charges of GaN and the polarization charges of FIG. 3 coincide with each other to minimize the polarization charges of the energy barrier and the electron blocking layer.

If smaller than the existing energy bandgap, the role of the electron blocking layer is small, and if the Al composition is too high, the crack generation, the surface formation and the quality are worsened during epitaxial growth. While maintaining the Al composition at about 17%, the In amount may be graded from about 8% to 0% in the direction of the second conductive semiconductor layer 116 on the last quantum wall of the active layer 114. .

Therefore, the polarization charge is minimized at the interface between the energy barrier and the electron blocking layer, and the In composition decreases as the distance from the interface decreases, thereby increasing the effective electron blocking layer height.

4 is an exemplary energy band diagram of a light emitting device according to an embodiment.

According to the embodiment, due to the coincidence of the amount of polarization charge at the interface, the band drop of the conduction band due to positive charge did not occur, and the barrier of the valence band disappeared. Accordingly, the size (h) of the energy bandgap of the electron blocking layer is increased compared to the prior art structure (see FIG. 1), and thus p-GaN, which is the second conductive semiconductor layer after the electron blocking layer, is increased. The QFL (Quasi-Fermi level) of the layer was raised.

In the embodiment, the inclination of the energy band diagram may increase from the active layer 114 toward the second conductive semiconductor layer 116 when the current blocking layer 126 is injected. Meanwhile, in the related art, the slope of the energy band diagram decreases from the active layer toward the second conductive semiconductor layer during the current injection.

According to the embodiment, the effect can be expected that the quasi-fermi energy level (QFL) of electrons formed by the current is farther from the conduction band edge in the structure of the embodiment.

5 is a diagram illustrating electron distribution during high current injection in the light emitting device according to the embodiment, and FIG. 6 is a view illustrating hole distribution during high current injection in the light emitting device according to the embodiment.

According to FIG. 5, in comparison with the electron distribution A3 of the prior art, the electron distribution B3 during the high current injection is significantly reduced in the p-GaN layer after the electron blocking layer. It can be seen that the decrease.

6 shows that the injection efficiency B4 of the hole in the embodiment is improved compared to the prior art A4.

FIG. 7 is an exemplary view illustrating light output B5 according to an injection current in a light emitting device according to an embodiment compared with the prior art A5.

According to the embodiment, it is possible to provide a high output high-efficiency light emitting device by improving the "drop phenomenon" in which the luminous efficiency decreases at high current as the current density increases.

8 is a diagram illustrating an internal quantum efficiency B6 according to an injection current in a light emitting device according to an embodiment compared to the prior art A6. Can be.

According to the embodiment, compared to the prior art, the electrons overflowed in the p-GaN layer after the electron blocking layer is significantly reduced, and the injection efficiency of the hole is improved, thereby improving the light output and the internal quantum efficiency at high current injection. .

According to the embodiment, it is possible to provide a high efficiency light emitting device, a manufacturing method of the light emitting device, a light emitting device package and an illumination system by reducing the internal field resulting from the polarization difference between the quantum wall and the electron blocking layer.

In addition, the embodiment can reduce the leakage current by effectively maintaining the barrier height of the electron blocking layer and increase the hole injection efficiency by reducing the barrier at the injection hole, thereby increasing the internal quantum efficiency. A light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system can be provided.

Referring back to FIG. 2, an embodiment provides a first electrode 140 and a second electrode 130 on the transparent electrode layer 129 on the first conductive semiconductor layer 112 exposed by mesa etching. It may include. The first electrode 140 and the second electrode 130 may be formed of a material having excellent electrical conductivity. For example, the first electrode 140 and the second electrode 130 may include titanium (Ti), chromium (Cr), nickel (Ni), aluminum (Al), platinum (Pt), gold (Au), and tungsten. (W) and molybdenum (Mo) may be formed of at least one, but is not limited thereto.

The transparent electrode layer 129 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), and indium gallium tin (IGTO). oxide), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IZO (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, Hf It may be formed to include at least one of, and is not limited to these materials.

According to the embodiment, it is possible to provide a high efficiency light emitting device, a manufacturing method of the light emitting device, a light emitting device package and an illumination system by reducing the internal field resulting from the polarization difference between the quantum wall and the electron blocking layer.

In addition, the embodiment reduces the leakage current by effectively maintaining the barrier height of the electron blocking layer and increases the hole injection efficiency by reducing the barrier at the injection hole, thereby increasing the internal quantum efficiency. A light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system can be provided.

In addition, the embodiment can provide a light emitting device, a manufacturing method of the light emitting device, a light emitting device package and an illumination system with improved reliability.

9 is a view illustrating a light emitting device package 200 in which a light emitting device is installed, according to embodiments.

The light emitting device package 200 according to the embodiment may include a package body 205, a third electrode layer 213 and a fourth electrode layer 214 installed on the package body 205, and the package body 205. The light emitting device 100 is installed at and 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 is included.

The package body 205 may include a silicon material, a synthetic resin material, or a metal material, and an inclined surface may be formed around the light emitting device 100.

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 a light emitting device of the horizontal type illustrated in FIG. 2, but is not limited thereto. A vertical light emitting device may also be applied.

The light emitting device 100 may be installed on the package body 205 or on the third electrode layer 213 or the fourth electrode layer 214.

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. In the exemplary embodiment, the light emitting device 100 is electrically connected to the third electrode layer 213 and the fourth electrode layer 214 through a wire.

The molding member 230 may surround the light emitting device 100 to protect the light emitting device 100. In addition, the molding member 230 may include a phosphor 232 to change the wavelength of the light emitted from the light emitting device 100.

A plurality of light emitting device packages according to the embodiment may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, a fluorescent sheet, or the like, which is an optical member, may be disposed on a path of light emitted from the light emitting device package. The light emitting device package, the substrate, and the optical member may function as a backlight unit or function as a lighting unit. For example, the lighting system may include a backlight unit, a lighting unit, a pointing device, a lamp, and a streetlight.

10 is a perspective view 1100 of a lighting unit according to an embodiment. However, the lighting unit 1100 of FIG. 10 is an example of a lighting system, but is not limited thereto.

In the embodiment, the lighting unit 1100 is connected to the case body 1110, the light emitting module unit 1130 installed on the case body 1110, and the case body 1110 and receive power from an external power source. It may include a terminal 1120.

The case body 1110 may be formed of a material having good heat dissipation characteristics. For example, the case body 1110 may be formed of a metal material or a resin material.

The light emitting module unit 1130 may include a substrate 1132 and at least one light emitting device package 200 mounted on the substrate 1132.

The substrate 1132 may be a circuit pattern printed on an insulator, and for example, a general printed circuit board (PCB), a metal core PCB, a flexible PCB, a ceramic PCB, and the like. It may include.

In addition, the substrate 1132 may be formed of a material that reflects light efficiently, or the surface may be formed of a color that reflects light efficiently, for example, white, silver, or the like.

The at least one light emitting device package 200 may be mounted on the substrate 1132. Each of the light emitting device packages 200 may include at least one light emitting diode (LED) 100. The light emitting diodes 100 may include colored light emitting diodes emitting red, green, blue, or white colored light, and UV light emitting diodes emitting ultraviolet (UV) light.

The light emitting module unit 1130 may be disposed to have a combination of various light emitting device packages 200 to obtain color and luminance. For example, a white light emitting diode, a red light emitting diode, and a green light emitting diode may be combined to secure high color rendering (CRI).

The connection terminal 1120 may be electrically connected to the light emitting module unit 1130 to supply power. In an embodiment, the connection terminal 1120 is coupled to the external power source by a socket, but is not limited thereto. For example, the connection terminal 1120 may be formed in a pin shape and inserted into an external power source, or may be connected to the external power source by a wire.

11 is an exploded perspective view 1200 of a backlight unit according to an embodiment. However, the backlight unit 1200 of FIG. 11 is an example of the illumination system, and the present invention is not limited thereto.

The backlight unit 1200 according to the embodiment includes a light guide plate 1210, a light emitting module unit 1240 that provides light to the light guide plate 1210, a reflective member 1220 under the light guide plate 1210, and the light guide plate. 1210, a bottom cover 1230 for accommodating the light emitting module unit 1240 and the reflective member 1220, but is not limited thereto.

The light guide plate 1210 serves to surface light by diffusing light. The light guide plate 1210 is made of a transparent material, for example, an acrylic resin series such as polymethyl metaacrylate (PMMA), polyethylene terephthlate (PET), polycarbonate (PC), cycloolefin copolymer (COC), and polyethylene naphthalate (PEN). It may include one of the resins.

The light emitting module unit 1240 provides light to at least one side of the light guide plate 1210 and ultimately serves as a light source of a display device in which the backlight unit is installed.

The light emitting module unit 1240 may be in contact with the light guide plate 1210, but is not limited thereto. Specifically, the light emitting module 1240 includes a substrate 1242 and a plurality of light emitting device packages 200 mounted on the substrate 1242. The substrate 1242 is mounted on the light guide plate 1210, But is not limited to.

The substrate 1242 may be a printed circuit board (PCB) including a circuit pattern (not shown). However, the substrate 1242 may include not only a general PCB, but also a metal core PCB (MCPCB), a flexible PCB (FPCB), and the like.

The plurality of light emitting device packages 200 may be mounted on the substrate 1242 such that a light emitting surface on which light is emitted is spaced apart from the light guide plate 1210 by a predetermined distance.

The reflective member 1220 may be formed under the light guide plate 1210. The reflection member 1220 reflects the light incident on the lower surface of the light guide plate 1210 so as to face upward, thereby improving the brightness of the backlight unit. The reflective member 1220 may be formed of, for example, PET, PC, or PVC resin, but is not limited thereto.

The bottom cover 1230 may accommodate the light guide plate 1210, the light emitting module unit 1240, the reflective member 1220, and the like. For this purpose, the bottom cover 1230 may be formed in a box shape having an opened upper surface, but the present invention is not limited thereto.

The bottom cover 1230 may be formed of a metal material or a resin material, and may be manufactured using a process such as press molding or extrusion molding.

According to the embodiment, it is possible to provide a high efficiency light emitting device, a manufacturing method of the light emitting device, a light emitting device package and an illumination system by reducing the internal field resulting from the polarization difference between the quantum wall and the electron blocking layer.

In addition, the embodiment can reduce the leakage current by effectively maintaining the barrier height of the electron blocking layer and increase the hole injection efficiency by reducing the barrier at the injection hole, thereby increasing the internal quantum efficiency. A light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system can be provided.

In addition, the embodiment can provide a light emitting device, a manufacturing method of the light emitting device, a light emitting device package and an illumination system with improved reliability.

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 each embodiment may be combined or modified with respect to other embodiments by those 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.

Claims (8)

A first conductive semiconductor layer;
An active layer formed on the first conductivity type semiconductor layer including a quantum well and a quantum wall;
An electron blocking layer on the active layer; And
And a second conductivity type semiconductor layer on the electron blocking layer.
The energy band gap of the electron blocking layer is increased in the direction of the second conductive semiconductor layer in the active layer. The method according to claim 1,
The electron blocking layer is
A light emitting device comprising a quaternary material containing indium (In). The method of claim 2,
The electron blocking layer is
In _y Al _x Ga _(1-xy) N (0≤x≤1,0≤y≤1),
A light emitting device in which the composition (y) of indium (In) is graded. The method of claim 3,
Of the electron blocking layer
The composition (x) of aluminum (Al) is a constant light emitting device. 5. The method of claim 4,
And a composition (y) of indium (In) of the electron blocking layer decreases in the direction of the second conductive semiconductor layer in the active layer. 5. The method of claim 4,
Of the electron blocking layer
The light emitting device of which Al is 17%. The method of claim 6,
The In composition of the electron blocking layer is graded from 8% to 0% in the direction of the second conductivity type semiconductor layer in the active layer. The method according to claim 1,
The electron blocking layer is
And a slope of an energy band diagram increases from the active layer toward the second conductive semiconductor layer during current injection.

Images