KR20130040012A - Light emitting device - Google Patents

Abstract

PURPOSE: A light emitting device is provided to prevent electron overflowing by using an electron tunneling layer and to improve reliability and luminous efficiency. CONSTITUTION: A light emitting structure includes a first semiconductor layer(120), a second semiconductor layer(150), and an active layer(130). The active layer includes well layers(Q1,Q2,Q3), barrier layers(B1,B2.B3), and an electron tunneling layer(180). The electron tunneling layer is formed between a first area(K1) of a second barrier and a second area(K2). The band gap of the electron tunneling layer is larger than that of the barrier layer. An electron barrier layer(140) is formed between the active layer and the second semiconductor layer. The band gap of the electron barrier layer is larger than that of the barrier layer in the active layer.

Description

[0001] LIGHT EMITTING DEVICE [0002]

An embodiment relates to a light emitting element.

LED (Light Emitting Diode) is a device that converts electrical signals into infrared, visible light or light using the characteristics of compound semiconductors. It is used in household appliances, remote controls, display boards, The use area of LED is becoming wider.

In general, miniaturized LEDs are made of a surface mounting device for mounting directly on a PCB (Printed Circuit Board) substrate, and an LED lamp used as a display device is also being developed as a surface mounting device type . Such a surface mount device can replace a conventional simple lighting lamp, which is used for a lighting indicator for various colors, a character indicator, an image indicator, and the like.

As the use area of the LED is widened as described above, it is important to increase the luminance of the LED as the brightness required for a lamp used in daily life and a lamp for a structural signal is increased.

Publication No. 10-2006-0090308 discloses a light emitting device having a multiple quantum well structure. Since the mobility of holes is lower than that of electrons, in the case of a well layer spaced from the hole injection layer, the probability of recombination of electrons and holes may be lowered in the case of a well layer spaced apart from the hole injection layer.

The embodiment provides a light emitting device in which electron overflow is prevented to improve reliability and luminous efficiency.

The light emitting device according to the embodiment includes a light emitting structure including a first semiconductor layer, a second semiconductor layer, and an active layer formed between the first semiconductor layer and the second semiconductor layer, wherein the active layer is at least one well. Layer, barrier layer, and electron tunneling layer.

The light emitting device according to the embodiment may include an electron tunneling layer to prevent electron overflowing and to improve reliability and luminous efficiency.

1 is a view showing a light emitting device according to an embodiment.
FIG. 2 is an enlarged cross-sectional view of a portion A of the light emitting device according to the embodiment of FIG. 1.
3 is a diagram illustrating an energy band diagram of a light emitting device according to an embodiment.
4 is a diagram illustrating an energy band diagram and movement of electrons in the light emitting device according to the embodiment.
5 is a view showing a light emitting device according to the embodiment.
6 is an enlarged cross-sectional view of a portion B of the light emitting device according to the embodiment of FIG. 5.
7 is a diagram illustrating an energy band diagram and movement of electrons in the light emitting device according to the embodiment.
8 is a perspective view of a light emitting device package including a light emitting device according to the embodiment.
9 is a cross-sectional view of a light emitting device package including a light emitting device according to the embodiment.
10 is a cross-sectional view of a light emitting device package including a light emitting device according to the embodiment.
11 is a perspective view showing a lighting system including a light emitting device according to the embodiment.
FIG. 12 is a cross-sectional view illustrating a CC ′ section of the lighting system of FIG. 11.
13 is an exploded perspective view of a liquid crystal display including the light emitting device according to the embodiment.
14 is an exploded perspective view of a liquid crystal display including the light emitting device according to the embodiment.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when flipping a device shown in the figure, a device described as "below" or "beneath" of another device may be placed "above" of another device. Thus, the exemplary term "below" can include both downward and upward directions. The device can also be oriented in other directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size and area of each component do not entirely reflect actual size or area.

Further, the angle and direction mentioned in the description of the structure of the light emitting device in the embodiment are based on those shown in the drawings. In the description of the structure of the light emitting device in the specification, reference points and positional relationship with respect to angles are not explicitly referred to, refer to the related drawings.

Referring to FIG. 1, the light emitting device 100 may include a support member 110 and a light emitting structure 160 disposed on the support member 110, and the light emitting structure 160 may include the first semiconductor layer 120. ), An active layer 130, an electron blocking layer 140, and a second semiconductor layer 150. And,

The support member 110 may be formed of any material having optical transparency, for example, sapphire (Al ₂ O ₃ ), GaN, ZnO, or AlO. However, the support member 110 is not limited thereto. Further, it can be a SiC supporting member having a higher thermal conductivity than a sapphire (Al ₂ O ₃ ) supporting member. However, the refractive index of the support member 110 may be smaller than the refractive index of the first semiconductor layer 120 for light extraction efficiency.

On the other hand, a PSS (Patterned SubStrate) structure may be provided on the upper surface of the support member 110 to enhance light extraction efficiency. The support member 110 referred to herein may or may not have a PSS structure.

A buffer layer (not shown) may be disposed on the support member 110 to mitigate lattice mismatch between the support member 110 and the first semiconductor layer 120 and allow the semiconductor layer to grow easily. The buffer layer (not shown) may be formed in a low temperature atmosphere, and may be formed of a material capable of alleviating the difference in lattice constant between the semiconductor layer and the support member. For example, materials such as GaN, InN, AlN, AlInN, InGaN, AlGaN, and InAlGaN can be selected and not limited thereto. A buffer layer (not shown) may be grown as a single crystal on the supporting member 110, and a buffer layer (not shown) grown by a single crystal may improve the crystallinity of the first semiconductor layer 120 grown on the buffer layer .

The light emitting structure 160 including the first semiconductor layer 120, the active layer 130, and the second semiconductor layer 150 may be formed on the buffer layer (not shown).

The first semiconductor layer 120 may be positioned on the buffer layer (not shown). The first semiconductor layer 120 may be implemented as an n-type semiconductor layer, and may provide electrons to the active layer 130.

The first semiconductor layer 120 is, for example, 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), for example For example, it may be selected from GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, and the like, and an n-type dopant such as Si, Ge, Sn, or the like may be doped.

Further, the semiconductor layer 120 may further include an undoped semiconductor layer (not shown), but the present invention is not limited thereto. The un-doped semiconductor layer is a layer formed for improving the crystallinity of the first semiconductor layer 120 and has a lower electrical conductivity than the first semiconductor layer 120 without doping the n-type dopant. May be the same as the semiconductor layer 120.

The active layer 130 may be formed on the first semiconductor layer 120. The active layer 130 may be formed of a single or multiple quantum well structure, a quantum-wire structure, a quantum dot structure, or the like using a compound semiconductor material of Group 3-V group elements.

When the active layer 130 is formed of a quantum well structure, for example, a well layer having a composition formula of In _x Al _y Ga _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1); It may have a single or multiple quantum well structure having a barrier layer having a composition formula of In _a Al _b Ga _1-ab N (0 ≦ a ≦ 1, 0 ≦ _b ≦ ₁ , 0 ≦ a + b ≦ 1). The well layer may be formed of a material having a band gap smaller than the band gap of the barrier layer.

A conductive clad layer (not shown) may be formed on and / or below the active layer 130. The conductive clad layer (not shown) may be formed of an AlGaN-based semiconductor and may have a band gap larger than that of the active layer 130.

The second semiconductor layer 140 may be implemented as a p-type semiconductor layer to inject holes into the active layer 130. The second semiconductor layer 140 is, for example, 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), for example For example, it may be selected from GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, and the like, and p-type dopants such as Mg, Zn, Ca, Sr, and Ba may be doped.

Meanwhile, an electron blocking layer (EBL) 140 may be formed between the active layer 130 and the second semiconductor layer 150, and the electron blocking layer 140 may have a first semiconductor layer when a high current is applied. Electrons injected from the 120 to the active layer 130 may be prevented from flowing back to the second semiconductor layer 150 without recombination in the active layer 130. The electron blocking layer 140 has a band gap relatively larger than that of the active layer 130, so that electrons injected from the first semiconductor layer 120 are injected into the second semiconductor layer 150 without recombination in the active layer 130. The phenomenon can be prevented. Accordingly, it is possible to increase the probability of recombination of electrons and holes in the active layer 140 and to prevent a leakage current.

Meanwhile, the above-described electron blocking layer 140 may have a bandgap larger than the bandgap of the barrier layer included in the active layer 130, and may be formed of a semiconductor layer including Al, such as p-type AlGaN. Not. In addition, the thickness of the electron blocking layer 140 is not limited, but is formed to be thicker than the thickness of the electron tunneling layer 180 to prevent overflow of electrons.

The first semiconductor layer 120, the active layer 130, the electron blocking layer 140, and the second semiconductor layer 150 described above may be, for example, metal organic chemical vapor deposition (MOCVD), chemical Chemical Vapor Deposition (CVD), Plasma-Enhanced Chemical Vapor Deposition (PECVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), Sputtering Sputtering) or the like, but is not limited thereto.

In addition, the doping concentrations of the conductive dopants in the first semiconductor layer 120 and the second semiconductor layer 150 can be uniformly or nonuniformly formed. That is, the plurality of semiconductor layers may be formed to have various doping concentration distributions, but the invention is not limited thereto.

The first semiconductor layer 120 may be a p-type semiconductor layer, the second semiconductor layer 150 may be an n-type semiconductor layer, and an n-type or p-type semiconductor may be formed on the second semiconductor layer 150. [ A third semiconductor layer (not shown) may be formed. Accordingly, the light emitting device 100 may have at least one of np, pn, npn, and pnp junction structures.

On the other hand, the first electrode 174 may be formed on at least one surface of the first semiconductor layer 120. That is, the first electrode 174 is electrically connected to the first semiconductor layer 120. For example, a portion of the active layer 130 and the second semiconductor layer 150 may be removed to expose a portion of the first semiconductor layer 120, and the first electrode may be disposed on the exposed first semiconductor layer 120. 174 may be formed. That is, the first semiconductor layer 120 includes a top surface facing the active layer 130 and a bottom surface facing the supporting member 110, and an upper surface includes a region exposed at least one region, and the first electrode 174 Can be disposed on the exposed area of the upper surface. However, the present invention is not limited thereto.

Meanwhile, a method of exposing a part of the first semiconductor layer 120 may use a predetermined etching method, but is not limited thereto. The etching method may be a wet etching method or a dry etching method.

The second electrode 172 may be formed on the second semiconductor layer 150.

Meanwhile, the first and second electrodes 172 and 174 may be conductive materials such as In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, W It may include a metal selected from Ti, Ag, Cr, Mo, Nb, Al, Ni, Cu, and WTi, or may include an alloy thereof, may be formed in a single layer or multiple layers, but is not limited thereto. .

2 is an enlarged cross-sectional view of a portion A of the light emitting device according to the embodiment of FIG. 1, FIG. 3 is an energy band diagram of the light emitting device according to the embodiment, and FIG. 4 is an energy band diagram of the light emitting device according to the embodiment. And the movement of electrons.

2 and 3, the active layer 130 may include at least one well layer Q1, Q2, and Q3 barrier layers B1, B2, and B3, and an electron tunneling layer 180. The tunneling layer 180 may have a band gap larger than the barrier layers B1, B2, and B3.

The active layer 130 of the light emitting device 100 may have a multi-quantum well structure, and thus the active layer 130 may include the first to third well layers Q1, Q2, and Q3 and the first to third barrier layers B1. , B2.B3).

Here, the well layer closest to the first semiconductor layer 120, and the barrier layer are defined as a first well layer Q1 and a first barrier layer B1.

The first through third well layers Q1, Q2 and Q3 and the first through third barrier layers B1, B2 and B3 may have a structure in which they are alternately stacked as shown in FIG.

Meanwhile, in FIG. 2, the first to third well layers Q1, Q2, and Q3 and the first to third barrier layers B1, B2, and B3 are formed, respectively, and the first to third barrier layers B1, B2, B3) and the first to third well layers Q1, Q2, and Q3 are alternately formed, but are not limited thereto, and the well layers Q1, Q2, and Q3 and the barrier layers B1, B2, and B3 may be alternately formed. ) May be formed to have any number, and the arrangement may also have any arrangement. In addition, as described above, the composition ratios, band gaps, and thicknesses of the materials forming the respective well layers Q1, Q2, and Q3, and the respective barrier layers B1, B2, and B3 may be different from each other. It is not limited as shown in 2. Hereinafter, the active layer 130 will be described based on the first to third well layers Q1, Q2 and Q3 and the first to third barrier layers B1, B2 and B3.

2 and 3, the active layer 130 may include an electron tunneling layer 180, and the electron tunneling layer 180 may have a larger band gap than the barrier layers B1, B2, and B3. .

Meanwhile, the electron tunneling layer 180 may be disposed in at least one barrier layer B1, B2, B3. In FIG. 2, the electron tunneling layer 180 is disposed in the second barrier layer B2, but the present invention is not limited thereto. The electron tunneling layer 180 may include the first to third barrier layers B1 and B2. B3) may be disposed. In addition, although the electron tunneling layer 180 is formed to be formed between the first and second regions K1 and K2 of the second barrier layer B2 in FIG. 2, the present invention is not limited thereto, and the first to third barrier layers are not limited thereto. The electron tunneling layer 180 may be formed at any position of the barrier layer of at least one of (B1, B2, B3).

The electron tunneling layer 180 may have a larger Al content than the barrier layers B1, B2, and B3. For example, the electron tunneling layer 180 has a composition of Al _a2 In _b2 Ga _{(1- ( a2 - b2 ))} N (0 ≦ _a2 ≦ 1, 0 ≦ _b2 ≦ 1, 0 ≦ _{a2 + b2} ≦ 1), and a barrier. When the layers B1, B2, B3 have a composition formula of In _a1 Al _b1 Ga _{1 - a1 - b1} N (0≤a1≤1, 0≤b1≤1, 0≤a1 + b1≤1), a2 is a1 It can have a larger value.

Accordingly, as shown in FIGS. 3 and 4, the electron tunneling layer 180 may have a band gap larger than the barrier layers B1, B2, and B3.

As shown in FIG. 4, the electron tunneling layer 180 has a larger Al content and bandgap than the barrier layers B1, B2. B3, such that the electron tunneling layer 180 is formed from the first semiconductor layer 120. Some of the injected electrons can be tunneled, and some of the electrons can function as an electron controlling layer. Since the electrons injected from the first semiconductor layer 120 may be partially blocked by the electron tunneling layer 180, the electron tunneling layer 180 may have electrons not recombined in the active layer 130. It is possible to prevent the electron overflowing phenomenon.

Meanwhile, when the electron blocking layer 140 is disposed between the active layer 130 and the second semiconductor layer 150, the electron blocking layer 140 passes from the active layer 130 to the second semiconductor layer 150 by the electron blocking layer 140. As the electrons are blocked, an excessive phenomenon of electron density may occur in the well layer adjacent to the second semiconductor layer 150, for example, the third well layer B3. Since the electron tunneling layer 180 is disposed between the third well layer B3 and the second semiconductor layer 150, an excessive increase in the electron density of the third well layer B3 is prevented, and thus the light emitting device ( The luminous efficiency of 100 may be improved.

On the other hand, when the thickness of the electron tunneling layer 180 is too large, the injection efficiency of electrons is reduced, and when too thin, the electron overflow prevention effect may not be secured. Therefore, the electron tunneling layer 180 may have a predetermined thickness to secure tunneling of some electrons and block some electrons, and may have a thickness of 1 nm to 3 nm.

On the other hand, when the Al content of the electron tunneling layer 180 is too large, the band gap is formed too large, and the electron injection efficiency is lowered. When the Al content is too small, the electron overflow prevention effect may not be secured. Therefore, the Al content of the electron tunneling layer 180 may be 5% to 15%. This may be any one of a molar ratio, a volume ratio, and a weight ratio, but is not limited thereto.

On the other hand, when the electron tunneling layer 180 having a large Al content and a band gap is formed in contact with the well layers Q1, Q2, and Q3, the lattice between the well layers Q1, Q2, Q3 and the electron tunneling layer 180 Piezoelectric polariziton may occur due to the constant difference. The electrostatic field generated by the piezoelectric polarization changes the energy band structure of the quantum well structure, distorts the distribution of electrons and holes, and may hinder emission efficiency. Thus, as shown in FIGS. 3 and 4, the electron tunneling layer 180 may be formed to be formed between the first and second regions K1 and K2 in the barrier layers B1, B2, and B3. It is not limited to this.

Meanwhile, the mobility of holes is lower than that of electrons, and when the electron tunneling layer 180 having a large band gap is formed adjacent to the second semiconductor layer 150, the electron tunneling layer 180 may block the movement of holes. As such, the barrier layers B1, B2, and B3 on which the electron tunneling layer 180 is disposed may be formed to be spaced apart from the second semiconductor layer 150, for example. For example, barrier layers B1, B2, and B3 on which the electron tunneling layer 180 is disposed may be formed on the first or second barrier layers B1 and B2. That is, the first or second barrier layers B1 and B2 on which the electron tunneling layer 180 is disposed are formed, and are formed between the first or second barrier layers B1 and B2 and the second semiconductor layer 150. 3 barrier layer (B3) and at least one well layer (Q1, Q2, Q3) may be formed to be disposed, but is not limited thereto.

5 is a view showing a light emitting device according to another embodiment.

Referring to FIG. 5, the light emitting device 200 according to the embodiment includes a support member 210, a first electrode layer 220, a first semiconductor layer 230, and an active layer 250 disposed on the support member 210. And a light emitting structure 270 including a second semiconductor layer 260, and a second electrode layer 282.

The support member 210 may be formed using a material having a high thermal conductivity, or may be formed of a conductive material. The support member 210 may be formed using a metal material or a conductive ceramic. The support member 210 may be formed as a single layer, and may be formed as a double structure or a multiple structure.

That is, the support member 210 may be formed of any one selected from a metal, for example, Au, Ni, W, Mo, Cu, Al, Ta, Ag, Pt, and Cr, or may be formed of two or more alloys. The above materials can be laminated. In addition, the support member 210 is Si, Ge, GaAs, ZnO, SiC, SiGe, GaN, Ga ₂ O ₃ It may be implemented as a carrier wafer such as.

Such a support member 210 facilitates the release of heat generated in the light emitting device 200, thereby improving the thermal stability of the light emitting device 200.

A first electrode layer 220 may be formed on the support member 210. The first electrode layer 220 may include an ohmic layer (not shown), a reflective layer (not shown) and a bonding layer (not shown). For example, the first electrode layer 220 may be a structure of an ohmic layer / a reflection layer / a bonding layer, a laminate structure of an ohmic layer / a reflection layer, or a structure of a reflection layer (including an ohmic layer) / a bonding layer. For example, the first electrode layer 220 may be formed by sequentially stacking a reflective layer and an ohmic layer on an insulating layer.

The reflective layer (not shown) may be disposed between an ohmic layer (not shown) and an insulating layer (not shown), and may be formed of a material having excellent reflection characteristics, such as Ag, Ni, Al, Rh, Pd, , Zn, Pt, Au, Hf, and combinations thereof. Alternatively, the metal material and the transparent conductive material such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, . Further, the reflective layer (not shown) can be laminated with IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni and the like. In addition, when the reflective layer (not shown) is formed of a material in ohmic contact with the light emitting structure 270 (eg, the first semiconductor layer 230), the ohmic layer (not shown) may not be formed separately, and the present invention is not limited thereto. I do not.

The ohmic layer (not shown) is in ohmic contact with the bottom surface of the light emitting structure 270, and may be formed in a layer or a plurality of patterns. The ohmic layer (not shown) may be formed of a transparent electrode layer and a metal. For example, ITO (indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tin oxide) ), IGZO (indium gallium zinc oxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IrO _x , RuO _x , RuO _x / Ni, Ag, Ni / IrO _x / Au, and Ni / IrO _x / Au / ITO. The ohmic layer (not shown) is for smoothly injecting a carrier into the first semiconductor layer 230 and is not necessarily formed.

In addition, the first electrode layer 220 may include a bonding layer (not shown), wherein the bonding layer (not shown) may be a barrier metal or a bonding metal, for example, Ti, Au, Sn, or Ni. It may include, but is not limited to, at least one of Cr, Ga, In, Bi, Cu, Ag, or Ta.

The light emitting structure 270 may include at least a first semiconductor layer 230, an active layer 250 and a second semiconductor layer 260 and may be formed between the first semiconductor layer 230 and the second semiconductor layer 260 And the active layer 250 may be disposed.

The first semiconductor layer 230 may be formed on the first electrode layer 220. The first semiconductor layer 230 may be implemented as a p-type semiconductor layer doped with a p-type dopant. The p-type semiconductor layer contains a semiconductor material, for example, having a compositional formula of _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1) GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN and the like may be selected, and p-type dopants such as Mg, Zn, Ca, Sr, and Ba may be doped.

The active layer 250 may be formed on the first semiconductor layer 230. The active layer 250 may be formed of a single or multiple quantum well structure, a quantum-wire structure, a quantum dot structure, or the like using a compound semiconductor material of Group 3-V group elements.

An active layer 250, the well having a composition formula of a quantum well structure formed of a case, for _{example, In x Al y Ga 1 -x-} y N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1) It may have a single or quantum well structure having a layer and a barrier layer having a compositional formula of In _a Al _b Ga _{1 -a- b} N (0≤a≤1, 0≤b≤1, 0≤a + b≤1). have. The well layer may be formed of a material having a band gap smaller than the band gap of the barrier layer.

A conductive clad layer (not shown) may be formed on and / or below the active layer 250. The conductive clad layer (not shown) may be formed of an AlGaN-based semiconductor and may have a band gap larger than that of the active layer 250.

Meanwhile, the electron blocking layer 240 may be formed between the active layer 250 and the first semiconductor layer 230, and the electron blocking layer 240 may be formed of the active layer 250 from the second semiconductor layer 260 when a high current is applied. ) May be an electron blocking layer that prevents electrons injected into the active layer 250 from flowing to the first semiconductor layer 230 without recombination. The electron blocking layer (not shown) has a band gap relatively larger than that of the active layer 250, so that electrons injected from the second semiconductor layer 260 do not recombine in the active layer 250 to the first semiconductor layer 230. Injection phenomenon can be prevented. Accordingly, the probability of recombination of electrons and holes in the active layer 250 can be increased and leakage current can be prevented.

Meanwhile, the above-described electron blocking layer 240 may have a bandgap larger than the bandgap of the barrier layer included in the active layer 250, and may be formed of a semiconductor layer including Al, such as p-type AlGaN. Not.

A second semiconductor layer 260 may be formed on the active layer 250. The second semiconductor layer 260 may be implemented as an n-type semiconductor layer, and the n-type semiconductor layer may be, for example, In _x Al _y Ga _{1 -xy} N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x A semiconductor material having a compositional formula of + y ≦ 1) may be selected from, for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, and the like, for example, n such as Si, Ge, Sn, Se, Te, etc. Type dopants may be doped.

A second electrode layer 282 electrically connected to the second semiconductor layer 260 may be formed on the second semiconductor layer 260. The second electrode layer 282 may include at least one pad or / . ≪ / RTI > The second electrode layer 282 may be disposed in the center region, the outer region, or the edge region of the upper surface of the second semiconductor layer 260, but the present invention is not limited thereto. The second electrode layer 282 may be disposed in a region other than the upper portion of the second semiconductor layer 260, but the present invention is not limited thereto.

The second electrode layer 282 may be formed of a conductive material such as In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, W, , Mo, Nb, Al, Ni, Cu, and WTi.

Meanwhile, the light emitting structure 270 may include a third semiconductor layer (not shown) having a polarity opposite to that of the second semiconductor layer 260 on the second semiconductor layer 260. Also, the first semiconductor layer 230 may be an n-type semiconductor layer, and the second semiconductor layer 260 may be a p-type semiconductor layer. Accordingly, the light emitting structure layer 270 may include at least one of an N-P junction, a P-N junction, an N-P-N junction, and a P-N-P junction structure.

A light extracting structure 284 may be formed on the upper portion of the light emitting structure 270.

The light extracting structure 270 may be formed on the upper surface of the second semiconductor layer 260 or may be formed on a light transmitting electrode layer (not shown) after a light transmitting electrode layer (not shown) is formed on the light emitting structure 270 But not limited to,

The light extracting structure 284 may be formed in a light transmitting electrode layer (not shown), or in a part or all of the upper surface of the second semiconductor layer 260. The light extracting structure 284 may be formed by performing etching on at least one region of the light transmitting electrode layer (not shown) or the upper surface of the second semiconductor layer 260, but is not limited thereto. The etching process includes a wet etching process and / or a dry etching process. As the etching process is performed, the upper surface of the light transmitting electrode layer (not shown) or the upper surface of the second semiconductor layer 260 forms the light extracting structure 284 And may include roughness. The roughness may be irregularly formed in a random size, but is not limited thereto. The roughness may be at least one of a texture pattern, a concave-convex pattern, and an uneven pattern, which is an uneven surface.

The roughness may be formed to have various shapes such as a cylinder, a polygonal column, a cone, a polygonal pyramid, a truncated cone, a polygonal pyramid, and the like, preferably including a horn shape.

Meanwhile, the light extracting structure 284 may be formed by a photoelectrochemical (PEC) method or the like, but is not limited thereto. Light generated from the active layer 250 may be transmitted through a light-transmitting electrode layer (not shown) or a second semiconductor layer (not shown) as the light extracting structure 284 is formed on the upper surface of the light- Can be prevented from being totally reflected and reabsorbed or scattered from the upper surface of the light emitting device 260, thereby contributing to improvement of light extraction efficiency of the light emitting device 200.

Passivation (not shown) may be formed on side and upper regions of the light emitting structure 270, and passivation (not shown) may be formed of an insulating material.

6 is an enlarged cross-sectional view of a portion B of the light emitting device according to the embodiment of FIG. 5, and FIG. 7 is a diagram illustrating an energy band diagram and movement of electrons of the light emitting device according to the embodiment. However, the description overlapping with the above description is omitted here.

6 and 7, the active layer 240 may include at least one well layer Q1, Q2, and Q3, a barrier layer B1, B2, and B3, and an electron tunneling layer 290. The electron tunneling layer 290 may have a larger bandgap than the barrier layers B1, B2, B3.

The active layer 240 of the light emitting device 200 may have a multi-quantum well structure, and thus the active layer 240 may include the first to third well layers Q1, Q2 and Q3 and the first to third barrier layers B1. , B2.B3).

Here, the well layer closest to the second semiconductor layer 260 and the barrier layer are defined as the first well layer Q1 and the first barrier layer B1.

In addition, the first to third well layers Q1, Q2 and Q3 and the first to third barrier layers B1, B2 and B3 may have a structure in which they are alternately stacked as shown in FIG. 6.

The electron tunneling layer 290 may be disposed in at least one barrier layer B1, B2. B3. In FIG. 6, the electron tunneling layer 290 is disposed in the second barrier layer B2, but the present invention is not limited thereto. The electron tunneling layer 290 may include the first to third barrier layers B1 and B2. B3) may be disposed. 6, the electron tunneling layer 290 is formed to be formed between the first and second regions K1 and K2 of the second barrier layer B2, but is not limited thereto. The electron tunneling layer 290 may be formed at any position of the barrier layer of at least one of (B1, B2, B3).

The electron tunneling layer 290 may have a larger Al content than the barrier layers B1, B2 and B3. For example, the electron tunneling layer 290 has a composition of Al _a2 In _b2 Ga _{(1- ( a2 - b2 ))} N (0 ≦ _a2 ≦ 1, 0 ≦ _b2 ≦ 1, 0 ≦ _{a2 + b2} ≦ 1), and a barrier When layers B1, B2 and B3 have a composition formula of In _a1 Al _b1 Ga _{1 - a1 - b1} N (0≤a1≤1, 0≤b1≤1, 0≤a1 + b1≤1), a2 is a1 It can have a larger value.

As shown in FIG. 7, the electron tunneling layer 290 has a larger Al content and bandgap than the barrier layers B1, B2. B3, such that the electron tunneling layer 290 is removed from the second semiconductor layer 260. Some of the injected electrons can be tunneled, and some of the electrons can function as an electron controlling layer. Since the electrons injected from the second semiconductor layer 260 may be partially blocked by the electron tunneling layer 290, the electron tunneling layer 290 may have electrons not recombined in the active layer 250. It is possible to prevent the electron overflowing phenomenon.

On the other hand, when the thickness of the electron tunneling layer 290 is too large, the injection efficiency of electrons is reduced, and when too thin, the electron overflow prevention effect may not be secured. Accordingly, the electron tunneling layer 290 may have a predetermined thickness to secure tunneling of some electrons and block some electrons, and may have a thickness of 1 nm to 3 nm.

On the other hand, if the Al content of the electron tunneling layer 290 is too large, the band gap is formed too large, and the electron injection efficiency is lowered. If the Al content is too small, the electron overflow prevention effect may not be secured. Therefore, the Al content of the electron tunneling layer 290 may be 5% to 15%. This may be any one of a molar ratio, a volume ratio, and a weight ratio, but is not limited thereto.

On the other hand, when the electron tunneling layer 290 having a large Al content and a band gap is formed to be in contact with the well layers Q1, Q2 and Q3, the lattice between the well layers Q1, Q2 and Q3 and the electron tunneling layer 290 is formed. Piezoelectric polariziton may occur due to the constant difference. The electrostatic field generated by the piezoelectric polarization changes the energy band structure of the quantum well structure, distorts the distribution of electrons and holes, and may hinder emission efficiency. Accordingly, the electron tunneling layer 290 may be formed to be formed between the first and second regions K1 and K2 in the barrier layers B1, B2 and B3, but is not limited thereto.

Meanwhile, the mobility of holes is lower than that of electrons, and when the electron tunneling layer 290 having a large band gap is formed adjacent to the first semiconductor layer 230, the electron tunneling layer 290 may block the movement of holes. As such, the barrier layers B1, B2, and B3 on which the electron tunneling layer 290 is disposed may be formed to be spaced apart from the first semiconductor layer 230, for example. For example, barrier layers B1, B2, and B3 on which the electron tunneling layer 290 is disposed may be formed on the first or second barrier layers B1 and B2. That is, the first or second barrier layers B1 and B2 on which the electron tunneling layer 290 is disposed are formed, and are formed between the first or second barrier layers B1 and B2 and the second semiconductor layer 260. 3 barrier layer (B3) and the well layer (Q1, Q2, Q3) may be formed to be disposed, but is not limited thereto.

8 to 10 are a perspective view and a cross-sectional view showing a light emitting device package according to the embodiment.

8 to 10, the light emitting device package 500 may include a body 510 having a cavity 520, first and second lead frames 540 and 550 mounted on the body 510, and a first one. And a light emitting device 530 electrically connected to the second lead frames 540 and 550, and an encapsulant (not shown) filled in the cavity 520 to cover the light emitting device 530.

The body 510 may be made of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), liquid crystal polymer (PSG), polyamide 9T (SPS), a metal material, sapphire (Al ₂ O ₃ ), beryllium oxide (BeO), and a printed circuit board (PCB). The body 510 may be formed by injection molding, etching, or the like, but is not limited thereto.

The inner surface of the body 510 may be formed with an inclined surface. The reflection angle of the light emitted from the light emitting device 530 can be changed according to the angle of the inclined surface, and thus the directivity angle of the light emitted to the outside can be controlled.

Concentration of light emitted to the outside from the light emitting device 530 increases as the directivity angle of light decreases. Conversely, as the directivity angle of light increases, the concentration of light emitted from the light emitting device 530 decreases.

The shape of the cavity 520 formed in the body 510 may be circular, rectangular, polygonal, elliptical, or the like, and may have a curved shape, but the present invention is not limited thereto.

The light emitting device 530 is mounted on the first lead frame 540 and may be, for example, a light emitting device emitting light of red, green, blue, white, or UV (ultraviolet) light emitting device emitting ultraviolet light. But it is not limited thereto. In addition, one or more light emitting elements 530 may be mounted.

The light emitting device 530 may be a horizontal type or a vertical type formed on the upper or lower surface of the light emitting device 530 or a flip chip Applicable.

The encapsulant (not shown) may be filled in the cavity 520 to cover the light emitting device 530.

The encapsulant (not shown) may be formed of silicon, epoxy, or other resin material. The encapsulant may be filled in the cavity 520 and ultraviolet or thermally cured.

In addition, the encapsulant (not shown) may include a phosphor, and the phosphor may be selected to be a wavelength of light emitted from the light emitting device 530 so that the light emitting device package 500 may emit white light.

The phosphor may be one of a blue light emitting phosphor, a blue light emitting phosphor, a green light emitting phosphor, a sulfur green light emitting phosphor, a yellow light emitting phosphor, a yellow red light emitting phosphor, an orange light emitting phosphor, and a red light emitting phosphor depending on the wavelength of light emitted from the light emitting device 530 Can be applied.

That is, the phosphor may be excited by the light having the first light emitted from the light emitting device 530 to generate the second light. For example, when the light emitting element 530 is a blue light emitting diode and the phosphor is a yellow phosphor, the yellow phosphor may be excited by blue light to emit yellow light, and blue light and blue light emitted from the blue light emitting diode As the excited yellow light is mixed, the light emitting device package 500 can provide white light.

Similarly, when the light emitting element 530 is a green light emitting diode, the magenta phosphor or the blue and red phosphors are mixed, and when the light emitting element 530 is a red light emitting diode, the cyan phosphors or the blue and green phosphors are mixed For example.

Such a fluorescent material may be a known fluorescent material such as a YAG, TAG, sulfide, silicate, aluminate, nitride, carbide, nitridosilicate, borate, fluoride or phosphate.

The first and second lead frames 540 and 550 may be formed of a metal material such as titanium, copper, nickel, gold, chromium, tantalum, (Pt), tin (Sn), silver (Ag), phosphorus (P), aluminum (Al), indium (In), palladium (Pd), cobalt (Co), silicon (Si), germanium , Hafnium (Hf), ruthenium (Ru), and iron (Fe). Also, the first and second lead frames 540 and 550 may be formed to have a single layer or a multilayer structure, but the present invention is not limited thereto.

The first and second lead frames 540 and 550 are separated from each other and electrically separated from each other. The light emitting device 530 is mounted on the first and second lead frames 540 and 550, and the first and second lead frames 540 and 550 are in direct contact with the light emitting device 530 or a soldering member (not shown). May be electrically connected through a material having conductivity such as C). In addition, the light emitting device 530 may be electrically connected to the first and second lead frames 540 and 550 through wire bonding, but is not limited thereto. Accordingly, when power is supplied to the first and second lead frames 540 and 550, power may be applied to the light emitting device 530. Meanwhile, a plurality of lead frames (not shown) may be mounted in the body 510 and each lead frame (not shown) may be electrically connected to the light emitting device 530, but is not limited thereto.

Meanwhile, referring to FIG. 10, the light emitting device package 500 according to the embodiment may include an optical sheet 580, and the optical sheet 580 may include a base portion 582 and a prism pattern 584. Can be.

The base portion 582 is made of a transparent material having excellent thermal stability as a support for forming the prism pattern 584. For example, the base portion 582 is made of polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polystyrene, and polyepoxy. It may be made of any one selected from the group, but is not limited thereto.

In addition, the base portion 582 may include a phosphor (not shown). As an example, the base portion 582 may be formed by curing the phosphor (not shown) evenly in a state in which the base portion 582 is uniformly dispersed. As such, when the base portion 582 is formed, the phosphor (not shown) may be uniformly distributed over the base portion 582.

On the other hand, a three-dimensional prism pattern 584 that refracts and collects light may be formed on the base portion 582. The material constituting the prism pattern 584 may be acrylic resin, but is not limited thereto.

The prism pattern 584 includes a plurality of linear prisms arranged in parallel with one another in one direction on one surface of the base portion 582, and a vertical cross section of the linear prism in the axial direction may be triangular.

Since the prism pattern 584 has an effect of condensing light, when the optical sheet 580 is attached to the light emitting device package 500, the linearity of the light may be improved, and thus the brightness of the light of the light emitting device package 500 may be improved. have.

On the other hand, the prism pattern 584 may include a phosphor (not shown).

The phosphor (not shown) is uniformly formed in the prism pattern 584 by forming the prism pattern 584 in a dispersed state, for example, by mixing with an acrylic resin to form a paste or slurry, and then forming the prism pattern 584. Can be included.

As such, when the phosphor (not shown) is included in the prism pattern 584, the uniformity and distribution of the light of the light emitting device package 500 may be improved, and in addition to the light condensing effect by the prism pattern 584, the phosphor (not shown) may be used. Due to the light scattering effect, the directivity of the light emitting device package 500 can be improved.

A plurality of light emitting device packages 500 according to the embodiment may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, or the like, which is an optical member, may be disposed on an optical path of the light emitting device package 500. Such a light emitting device package, a substrate, and an optical member can function as a light unit. Another embodiment may be implemented as a display device, an indicator device, or a lighting system including the light emitting device or the light emitting device package described in the above embodiments, and for example, the lighting system may include a lamp or a street lamp.

FIG. 11 is a perspective view illustrating a lighting device including a light emitting device package according to an embodiment, and FIG. 12 is a cross-sectional view illustrating a C-C 'cross section of the lighting device of FIG. 11.

11 and 12, the lighting device 600 may include a body 610, a cover 630 fastened to the body 610, and a closing cap 650 located at both ends of the body 610. have.

A light emitting device module 640 is coupled to a lower surface of the body 610. The body 610 is electrically conductive so that heat generated from the light emitting device package 644 can be emitted to the outside through the upper surface of the body 610. [ And a metal material having an excellent heat dissipation effect.

The light emitting device package 644 may be mounted on the PCB 642 in a multi-color, multi-row manner to form an array. The light emitting device package 644 may be mounted at equal intervals or may be mounted with various spacings as required. As the PCB 642, MPPCB (Metal Core PCB) or FR4 material PCB can be used.

The cover 630 may be formed in a circular shape so as to surround the lower surface of the body 610, but is not limited thereto.

The cover 630 protects the internal light emitting element module 640 from foreign substances or the like. The cover 630 may include diffusion particles so as to prevent glare of light generated in the light emitting device package 644 and uniformly emit light to the outside, and may include at least one of an inner surface and an outer surface of the cover 630 A prism pattern or the like may be formed on one side. Further, the phosphor may be applied to at least one of the inner surface and the outer surface of the cover 630.

On the other hand, since the light generated from the light emitting device package 644 is emitted to the outside through the cover 630, the cover 630 should have excellent light transmittance, and has sufficient heat resistance to withstand the heat generated from the light emitting device package 644. The cover 630 is preferably formed of a material including polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), or the like. .

The finishing cap 650 is located at both ends of the body 610 and can be used to seal the power supply unit (not shown). In addition, the finishing cap 650 is provided with the power supply pin 652, so that the lighting apparatus 600 according to the embodiment can be used immediately without a separate device on the terminal from which the conventional fluorescent lamp is removed.

13 is an exploded perspective view of a liquid crystal display including the light emitting device according to the embodiment.

FIG. 13 illustrates an edge-light method, and the liquid crystal display 700 may include a liquid crystal display panel 710 and a backlight unit 770 for providing light to the liquid crystal display panel 710.

The liquid crystal display panel 710 can display an image using light provided from the backlight unit 770. The liquid crystal display panel 710 may include a color filter substrate 712 and a thin film transistor substrate 714 facing each other with a liquid crystal therebetween.

The color filter substrate 712 can realize the color of an image to be displayed through the liquid crystal display panel 710.

The thin film transistor substrate 714 is electrically connected to the printed circuit board 718 on which a plurality of circuit components are mounted through the driving film 717. The thin film transistor substrate 714 may apply a driving voltage provided from the printed circuit board 718 to the liquid crystal in response to a driving signal provided from the printed circuit board 718. [

The thin film transistor substrate 714 may include a thin film transistor and a pixel electrode formed as a thin film on another substrate of a transparent material such as glass or plastic.

The backlight unit 770 may include a light emitting device module 720 for outputting light, a light guide plate 730 for changing the light provided from the light emitting device module 720 into a surface light source, and providing the light to the liquid crystal display panel 710. Reflective sheet for reflecting the light emitted from the back of the light guide plate 730 and the plurality of films 752, 766, 764 to uniform the luminance distribution of the light provided from the 730 and improve the vertical incidence ( 740.

The light emitting device module 720 may include a PCB substrate 722 for mounting a plurality of light emitting device packages 724 and a plurality of light emitting device packages 724 to form an array.

Meanwhile, the backlight unit 770 includes a diffusion film 766 for diffusing light incident from the light guide plate 730 toward the liquid crystal display panel 710, and a prism film 750 for condensing the diffused light to improve vertical incidence. It may be configured as), and may include a protective film 764 for protecting the prism film 750.

14 is an exploded perspective view of a liquid crystal display including the light emitting device according to the embodiment. However, the parts shown and described in FIG. 13 will not be repeatedly described in detail.

14 is a direct view, the liquid crystal display device 800 may include a liquid crystal display panel 810 and a backlight unit 870 for providing light to the liquid crystal display panel 810.

Since the liquid crystal display panel 810 is the same as that described with reference to FIG. 13, a detailed description thereof will be omitted.

The backlight unit 870 includes a plurality of light emitting element modules 823, a reflective sheet 824, a lower chassis 830 in which the light emitting element module 823 and the reflective sheet 824 are accommodated, And a plurality of optical films 860. The diffuser plate 840 and the plurality of optical films 860 are disposed on the light guide plate 840. [

LED Module 823 A plurality of light emitting device packages 822 and a plurality of light emitting device packages 822 may be mounted to include a PCB substrate 821 to form an array.

The reflective sheet 824 reflects light generated from the light emitting device package 822 in a direction in which the liquid crystal display panel 810 is positioned, thereby improving light utilization efficiency.

Light generated in the light emitting element module 823 is incident on the diffusion plate 840 and an optical film 860 is disposed on the diffusion plate 840. The optical film 860 may include a diffusion film 866, a prism film 850, and a protective film 864.

Meanwhile, the light emitting device according to the embodiment is not limited to the configuration and method of the embodiments described above, but the embodiments may be modified so that all or some of the embodiments may be selectively And may be configured in combination.

In addition, while the preferred embodiments have been shown and described, the present invention is not limited to the above-described specific embodiments, and the present invention is not limited to the specific scope of the present invention as claimed in the claims. Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

100 light emitting element 120 first semiconductor layer
130: active layer 140: electron blocking layer
150: second semiconductor layer 160: light emitting structure
Q1, Q2, Q3: well layer B1, B2, B3: barrier layer
180: electron tunneling layer

Claims (11)

A light emitting structure including a first semiconductor layer, a second semiconductor layer, and an active layer formed between the first semiconductor layer and the second semiconductor layer; And
An electron blocking layer between the active layer and the second semiconductor layer,
The active layer includes at least one well layer, a barrier layer and an electron tunneling layer. The method of claim 1,
The electron tunneling layer,
A light emitting device disposed in at least one barrier layer of the barrier layer. The method of claim 1,
The electron tunneling layer has a larger band gap than the barrier layer. The method of claim 1,
The barrier layer comprises Al _a1 Ga _{(1- a1 )} N (0 ≦ _a1 ≦ _{1 )} ,
The electron tunneling layer includes Al _a2 Ga _{(1- a2 )} N (0≤a2≤1),
Wherein a2 is larger than a1. The method of claim 1,
The barrier layer includes Al _a1 In _b1 Ga _{(1- ( a1 - b1 ))} N (0 ≦ _a1 ≦ 1, 0 < _b1 ≦ 1, 0 ≦ a1 + b1 ≦ 1),
The electron tunneling layer includes Al _a2 In _b2 Ga _{(1- ( a2 - b2 ))} N (0 ≦ _a2 ≦ 1, 0 < _b2 ≦ 1, 0 ≦ _{a2 + b2} ≦ 1),
Wherein a2 is larger than a1. The method according to any one of claims 4 to 5,
A2 is 0.05 to 0.15. The method of claim 1,
The electron tunneling layer,
Light emitting device having a thickness of 1nm to 3nm. The method of claim 1,
The second semiconductor layer,
A light emitting device doped with p-type. The method of claim 1,
The barrier layer comprises a first barrier layer and a second barrier layer formed between the first barrier layer and the second semiconductor layer,
And the electron tunneling layer disposed in the first barrier layer. The method of claim 1,
The thickness of the electron blocking layer is thicker than the thickness of the electron tunneling layer. The method of claim 1,
The electron blocking layer includes AlGaN.

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