KR102163949B1 - Light emitting device - Google Patents

Abstract

The light emitting device according to the embodiment includes a first semiconductor layer, a second semiconductor layer, an active layer disposed between the first semiconductor layer and the second semiconductor layer, and an intermediate layer disposed between the active layer and the second semiconductor layer. And the intermediate layer includes InAlGaN or AlGaN, and includes a first layer adjacent to the active layer and a second layer adjacent to the second semiconductor layer, and the first layer is an undoped layer, and the first layer The second layer is doped with a dopant having the same polarity as the second semiconductor layer, and the band gap energy of the first layer is greater than the band gap energy of the second layer.

Description

Light emitting device

The embodiment relates to a light emitting device.

As a representative example of a light emitting device, LED (Light Emitting Diode) is a device that converts an electric signal into infrared, visible light, or light using the characteristics of a compound semiconductor. It is used in automation equipment and the like, and the area of use of LEDs is gradually expanding.

Usually, miniaturized LEDs are made in a surface mount device type to directly mount on a PCB (Printed Circuit Board) substrate, and accordingly, LED lamps used as display devices are also being developed in a surface mount device type. . Such a surface mount device can replace the existing simple lighting lamp, and it is used as a lighting indicator, a character display, and an image display that produce various colors.

As the area of use of the LED is expanded as described above, the luminance required for a light used in life, a light for a rescue signal, etc. increases, so it is important to increase the luminance of the LED.

An embodiment is to provide a light emitting device having increased hole injection efficiency and increased efficiency.

The light emitting device according to the embodiment includes a first semiconductor layer, a second semiconductor layer, an active layer disposed between the first semiconductor layer and the second semiconductor layer, and an intermediate layer disposed between the active layer and the second semiconductor layer. And the intermediate layer includes InAlGaN or AlGaN, and includes a first layer adjacent to the active layer and a second layer adjacent to the second semiconductor layer, and the first layer is an undoped layer, and the first layer The second layer is doped with a dopant having the same polarity as the second semiconductor layer, and the band gap energy of the first layer is greater than the band gap energy of the second layer.

In the light emitting device according to the embodiment, since the intermediate layer is disposed between the second semiconductor layer and the active layer, the piezoelectric polarization phenomenon is improved and the probability of recombination of electrons and holes is increased, and luminous efficiency may be improved.

In addition, since the first layer adjacent to the active layer is an undoped layer, and the second layer adjacent to the second semiconductor layer is doped with a p-type dopant, the amount of p-type dopant diffused into the active layer is reduced so that the light intensity of the light emitting device is not reduced. There is an advantage.

In addition, in the embodiment, since the Al content of the first layer adjacent to the active layer is greater than the Al content of the second layer adjacent to the second semiconductor layer, luminous efficiency can be improved and stress of the semiconductor layer can be reduced.

1 is a cross-sectional view illustrating a light emitting device according to an embodiment.
FIG. 2 is a partially enlarged view of an enlarged portion A of FIG. 1.
3 is a diagram illustrating an energy band diagram of a light emitting device according to the embodiment of FIG. 1.
4 is a cross-sectional view illustrating a light emitting device according to another embodiment.
5 is a cross-sectional view showing a cross section of a light emitting device package including a light emitting device according to an embodiment.
6 is an exploded perspective view of a display device including a light emitting device according to an exemplary embodiment.
7 is a cross-sectional view of the display device of FIG. 6.
8 is an exploded perspective view of a lighting device including a light emitting device according to an embodiment.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only these embodiments make the disclosure of the present invention complete, and are common knowledge in the art It is provided to completely inform the scope of the invention to those who have, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

Spatially relative terms "below", "beneath", "lower", "above", "upper", etc., as shown in the figure It may be used to easily describe the correlation between the device or components and other devices or components. Spatially relative terms should be understood as terms including different directions of the device during use or operation in addition to the directions shown in the drawings. For example, if an element shown in the figure is turned over, an element described as “below” or “beneath” of another element may be placed “above” another element. Accordingly, the exemplary term “below” may include both directions below and above. The device may be oriented in other directions, and thus spatially relative terms may be interpreted according to the orientation.

The terms used in the present specification are for describing exemplary embodiments and are not intended to limit the present invention. In this specification, the singular form also includes the plural form unless specifically stated in the phrase. As used in the specification, "comprises" and/or "comprising" refers to the presence of one or more other components, steps, actions and/or elements, and/or elements, steps, actions and/or elements mentioned. Or does not exclude additions.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used as meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. Also, the size and area of each component do not fully reflect the actual size or area.

In addition, the angles and directions mentioned in the process of describing the structure of the light emitting device in the embodiment are based on those described in the drawings. In the description of the structure constituting the light emitting device in the specification, when the reference point and the positional relationship with respect to the angle are not clearly mentioned, the related drawings will be referred to.

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

Referring to FIG. 1, the light emitting device 100 may include a substrate 110 and a light emitting structure disposed on the substrate 110, and the light emitting structure includes a first semiconductor layer 120, an active layer 130, and an intermediate layer. (180) and the second semiconductor layer 150 may be included.

The substrate 110 may be formed of a material having a light-transmitting property, for example, sapphire (Al ₂ O ₃ ), GaN, ZnO, or AlO, but is not limited thereto.

Further, the substrate 110 may be formed of a material suitable for growth of semiconductor materials, a carrier wafer. It can be formed of a material having excellent thermal conductivity, including a conductive substrate or an insulating substrate, for example, a SiC substrate having a higher thermal conductivity than a sapphire (Al ₂ O ₃ ) substrate or Si, GaAs, GaP, InP, Ga ₂ At least one of O ₃ may be used.

Meanwhile, an uneven structure may be provided on the upper surface of the substrate 110 to increase light extraction efficiency. The substrate 110 referred to herein may or may not have an uneven structure.

On the other hand, a buffer layer (not shown) may be positioned on the substrate 110 to relieve lattice mismatch between the substrate 110 and the first semiconductor layer 120 and allow the semiconductor layer to be easily grown. The buffer layer (not shown) may be formed in a low temperature atmosphere, and may be made of a material capable of reducing a difference in lattice constant between the semiconductor layer and the substrate 110. For example, materials such as GaN, InN, AlN, AlInN, InGaN, AlGaN, and InAlGaN may be included, but are not limited thereto. .

The buffer layer (not shown) can be grown as a single crystal on the substrate 110, and the buffer layer (not shown) grown as a single crystal can improve the crystallinity of the first semiconductor layer 120 grown on the buffer layer (not shown). have.

A light emitting structure 160 including a first semiconductor layer 120, an active layer 130, and a 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 formed of a semiconductor compound and may be doped with a first conductive dopant. For example, 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 n-type dopants such as Si, Ge, Sn, Se, and Te may be doped.

Further, an undoped semiconductor layer (not shown) may be further included under the first semiconductor layer 120, but the embodiment is not limited thereto. The undoped semiconductor layer is a layer formed to improve the crystallinity of the first semiconductor layer 120, except that the n-type dopant is not doped and has lower electrical conductivity than the first semiconductor layer 120. It may be the same as the semiconductor layer 120.

An 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 a group 3-5 element.

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

In addition, when the active layer 130 has a multiple quantum well structure, each well layer (not shown) may have different In content and different band gaps, which will be described later with reference to FIG. 2.

A conductive cladding layer (not shown) may be formed above or/and below the active layer 130. The conductive cladding layer (not shown) may be formed of a semiconductor, and may have a band gap larger than that of the active layer 130. For example, the conductive cladding layer (not shown) may be formed including AlGaN.

The second semiconductor layer 150 may be formed of a semiconductor compound to inject holes into the active layer 130 and may be doped with a second conductive dopant. For example, the second semiconductor layer 140 may be implemented as a p-type semiconductor layer. The second semiconductor layer 150 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, etc., and p-type dopants such as Mg, Zn, Ca, Sr, Ba, etc. may be doped.

Meanwhile, the intermediate layer 180 may be formed between the active layer 130 and the second semiconductor layer 150, and the intermediate layer 180 is injected from the first semiconductor layer 120 to the active layer 130 when a high current is applied. It is possible to prevent electrons from flowing to the second semiconductor layer 150 without being recombined in the active layer 130.

The intermediate layer 180 has a relatively larger band gap than the active layer 130, so that electrons injected from the first semiconductor layer 120 are not recombined in the active layer 130 and are injected into the second semiconductor layer 150 Can be prevented. Accordingly, the probability of recombination of electrons and holes in the active layer 130 can be increased and leakage current can be prevented.

The first semiconductor layer 120, the active layer 130, the intermediate layer 180, and the second semiconductor layer 150 described above are, for example, metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD). ; Chemical Vapor Deposition), Plasma-Enhanced Chemical Vapor Deposition (PECVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), Sputtering, etc. It may be formed using the method of, but is not limited thereto.

In addition, the doping concentration of the conductive dopant in the first semiconductor layer 120 and the second semiconductor layer 150 may be uniformly or non-uniformly formed. That is, the plurality of semiconductor layers may be formed to have various doping concentration distributions, but the embodiment is not limited thereto.

In addition, the first semiconductor layer 120 may be implemented as a p-type semiconductor layer, the second semiconductor layer 150 may be implemented as an n-type semiconductor layer, and the second semiconductor layer 150 on the second semiconductor layer 150 A third semiconductor layer (not shown) including an n-type or p-type semiconductor layer opposite to the polarity of) may be formed. Accordingly, the light emitting device 100 may have at least one of an np, pn, npn, and pnp junction structure.

A translucent electrode layer 170 may be formed on the second semiconductor layer 150.

The translucent electrode layer 170 is ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrO _x , RuO _x , RuO _x /ITO, Ni/IrO _x /Au, and Ni/IrO _x /Au/ITO. Accordingly, the light generated in the active layer 130 can be radiated to the outside, and the current clustering phenomenon can be prevented by being formed on the entire or part of the outer surface of the second semiconductor layer 150.

Meanwhile, a first electrode 172 electrically connected to the first semiconductor layer 120 may be disposed on the first semiconductor layer 120.

For example, a portion of the active layer 130 and the second semiconductor layer 150 may be partially removed to expose a portion of the first semiconductor layer 120, and the first electrode ( 172) may be formed. That is, the first semiconductor layer 120 includes an upper surface facing the active layer 130 and a lower surface facing the substrate 110, the upper surface includes at least one exposed area, and the first electrode 172 is an upper surface Can be placed on the exposed area of the. However, it 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. In addition, the etching method may be a wet etching method or a dry etching method.

In addition, a second electrode 174 may be formed on the second semiconductor layer 150.

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

Referring to FIG. 2, the active layer 130 of the light emitting device 100 may have a multiple quantum well structure, and thus the active layer 130 includes first to third well layers Q1, Q2, Q3 and first to It may include a third barrier layer (B1, B2, B3).

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. 2.

Meanwhile, in FIG. 2, first to third well layers Q1, Q2, Q3 and first to third barrier layers B1, B2, B3, and the first to third well layers Q1 and Q2 are formed, respectively. , Q3) and the first to third barrier layers B1, B2, and B3 are shown to be alternately stacked, but are not limited thereto, and the well layers Q1, Q2, Q3 and the barrier layers B1, B2, B3) can be formed to have any number, and the arrangement can also have any arrangement. In addition, as described above, the composition ratio, band gap, and thickness of the materials forming each well layer (Q1, Q2, Q3), and each of the barrier layers (B1, B2, B3) may be different from each other. It is not limited as shown in 2.

The barrier layers B1, B2, and B3 may have a larger band gap energy than the well layers Q1, Q2, and Q3. For example, the barrier layers B1, B2, and B3 may contain GaN, and the well layers Q1, Q2, and Q3 may contain InGaN.

Referring back to FIGS. 1 to 3, the intermediate layer 180 may be disposed between the active layer 130 and the second semiconductor layer 150. In addition, the intermediate layer 180 may have a larger lattice constant than the second semiconductor layer 150.

The intermediate layer 180 serves to improve the injection efficiency of holes from the second semiconductor layer 150 to the active layer 130 by mitigating the piezoelectric polarization effect between the active layer 130 and the second semiconductor layer 150.

The intermediate layer 180 may be formed to have a thickness of 20 nm to 40 nm. When the thickness of the intermediate layer 180 is formed to be thinner than 20 nm, the piezoelectric polarization phenomenon of the second semiconductor layer 150 and the active layer 130 cannot be alleviated, and when a high current is applied, the active layer ( When electrons injected into the second semiconductor layer 150 are not recombined in the active layer 130 and flow to the second semiconductor layer 150 cannot be prevented, and the thickness of the intermediate layer is formed thicker than 40 nm, the active layer in the second semiconductor layer 150 Hole injection efficiency into (130) may be reduced. However, it is not limited thereto.

In addition, the band gap energy of the intermediate layer 180 may be greater than the band gap energy of the barrier layers B1 to B3 of the active layer 130. For example, the intermediate layer 180 may include InAlGaN or AlGaN.

The intermediate layer 180 may have a structure in which a plurality of layers are stacked. For example, the intermediate layer 180 may include a first layer 181 adjacent to the active layer 130 and a second layer 182 adjacent to the second semiconductor layer 150.

Specifically, the first layer 181 may be disposed in contact with the barrier layer B3 of the active layer 130.

The first layer 181 is an undoped layer, and the second layer 182 may be doped with a dopant having the same polarity as the second semiconductor layer 150.

The first layer 181 is formed of an undoped layer. Here, the undoped layer means that the second layer 182 is not doped with the same dopant, or is doped with a very low concentration.

The second layer 182 may be doped with a p-type dopant, which is a dopant having the same polarity as the second semiconductor layer 150. Specifically, the intermediate layer 180 is doped with a p-type dopant, and the p-type dopant may include any one of Mg, Zn, Ca, Sr, and Ba. For example, the intermediate layer 180 may be doped with Mg (magnesium).

If the intermediate layer 180 is doped with a p-type dopant, the hole injection efficiency injected from the second semiconductor layer 150 to the intermediate layer 180 is improved, but the p-type dopant diffuses into the adjacent active layer 130. Diffusion) occurs. The p-type dopant diffused into the active layer 130 causes a problem of lowering the luminous intensity of the light emitting device.

Therefore, the first layer 181 adjacent to the active layer 130 is configured as an undoped layer, and when a p-type dopant is doped on the second layer 182 adjacent to the second semiconductor layer 150, the active layer 130 is formed. It has an effect of improving the injection efficiency of holes injected from the second semiconductor layer 150 to the active layer 130 without reducing the luminous intensity of the light emitting device by reducing the amount of the diffused p-type dopant.

As a result, the light emitting device of the embodiment has an effect of improving luminous efficiency without lowering the luminous intensity. In addition, the operating voltage of the light emitting device is also reduced.

For example, when Mg is doped on the second layer 182 with a p-type dopant, the doping concentration of the second layer 182 may be 5E18 to 5E19 cm ^-3 . If the doping concentration of Mg is too low, the effect of improving the injection efficiency of holes injected from the second semiconductor layer 150 to the active layer 130 is not significant, and if the doping concentration of Mg is too high, the active layer in the intermediate layer 180 This is because the amount of Mg diffused to (130) increases and the luminous intensity of the light emitting device decreases.

Meanwhile, the band gap energy of the first layer 181 and the second layer 182 may be greater than the band gap energy of the active layer 130 and the second semiconductor layer 150, and the band gap of the first layer 181 The energy may be greater than the band gap energy of the second layer 182.

Specifically, the Al (aluminum) content of the first layer 181 may be greater than the Al content of the second layer 182. Accordingly, the first layer 181 adjacent to the active layer 130 has a higher Al content than the second layer 182, so that when a high current is applied, electrons injected from the first semiconductor layer 120 to the active layer 130 are transferred to the active layer ( 130) without being recombined and flowing to the second semiconductor layer 150 can be prevented, and the Al content of the second layer 182 adjacent to the second semiconductor layer 150 is lower than that of the first layer 181 and thus excessive Stress due to Al content can be relieved.

More specifically, the Al content of the first layer 181 may be 15% to 30%. When the Al content of the first layer 181 is lower than 15%, the band gap energy is lowered so that electrons injected from the first semiconductor layer 120 to the active layer 130 are not recombined in the active layer 130 and the second semiconductor layer If the phenomenon of flowing to 150 cannot be prevented and the Al content of the first layer 181 is greater than 30%, the band gap energy is too high, and thus holes from the second semiconductor layer 150 to the active layer 130 This is because the injection efficiency may decrease.

In addition, the Al content of the second layer 182 may be 10% to 18%. When the Al content of the second layer 182 is lower than 10%, the band gap energy is lowered so that electrons injected from the first semiconductor layer 120 to the active layer 130 are not recombined in the active layer 130 and the second semiconductor layer This is because the phenomenon of flowing to 150 cannot be prevented, and when the Al content of the second layer 182 is greater than 18%, the Al content is too high and stress cannot be relaxed.

Meanwhile, the thickness of the first layer 181 may be 5 nm to 10 nm. When the thickness of the first layer 181 is formed to be thinner than 5 nm, the piezoelectric polarization phenomenon of the second semiconductor layer 150 and the active layer 130 cannot be alleviated, and the active layer 130 from the first semiconductor layer 120 When electrons injected into the active layer 130 are not recombined in the active layer 130 and flow to the second semiconductor layer 150 cannot be prevented, and the thickness of the first layer 181 is formed thicker than 10 nm, the second semiconductor layer 150 ) To the active layer 130 may reduce the hole injection efficiency.

In addition, the thickness of the second layer 182 may be 10 nm to 25 nm. When the thickness of the second layer 182 is thinner than 10 nm, electrons injected from the first semiconductor layer 120 to the active layer 130 are not recombined in the active layer 130 and flow to the second semiconductor layer 150. If the phenomenon cannot be prevented and the thickness of the second layer 182 is formed thicker than 25 nm, the hole injection efficiency from the second semiconductor layer 150 to the active layer 130 may be reduced, and the stress of the semiconductor layer may be reduced. Because it can increase.

If the band gap of the intermediate layer 180 is too low, the second semiconductor layer 150 cannot serve to confine holes supplied to the active layer 130, and if the band gap energy is too large, the second semiconductor layer 150 ) To reduce the injection efficiency of holes supplied to the active layer 130. In the semiconductor layer, a piezoelectric polarization may occur due to a difference in lattice constant between the semiconductor layers and stress due to orientation. Since the semiconductor material forming the light emitting device has a large piezoelectric coefficient, very large polarization may occur even with a small strain. The electric field caused by the two polarizations changes the structure of the energy band of the light-emitting device, thereby distorting the distribution of electrons and holes. This effect is called the quantum confined stark effect (QCSE), which induces low internal quantum efficiency in light emitting devices that emit light through recombination of electrons and holes, and emits light such as red shift of the emission spectrum. It may adversely affect the electrical and optical properties of the device. In particular, the polarization effect as described above is further increased by this strain, and the internal electric field is strengthened, and accordingly, the band is bent according to the electric field and the triangle potential well (the second semiconductor layer 150 and the active layer 130) has a sharp shape. Between them), and a shape in which electrons or holes are concentrated in this triangle potential well can occur. Therefore, the recombination rate of electrons and holes may decrease. That is, there is a problem of lowering the hole injection efficiency from the second semiconductor layer 150 to the active layer 130.

On the other hand, since the crystal defect due to the difference in lattice constant between the substrate 110 and the light emitting structure formed on the substrate 110 tends to increase according to the growth direction, the second formed at a position most spaced apart from the substrate 110 The semiconductor layer 150 may have the largest crystal defect. Considering the fact that the hole mobility is lower than the electron mobility, the decrease in the hole injection efficiency due to the decrease in the crystallinity of the second semiconductor layer 150 is the luminous efficiency of the light emitting device 100 Can decrease.

As in the above-described embodiment, when the intermediate layer 180 is disposed between the active layer 130 and the second semiconductor layer 150 and the intermediate layer 180 has a large lattice constant, the occurrence of the above-described triangle potential well is reduced. Thus, the recombination rate of electrons and holes may be increased, and luminous efficiency of the light emitting device 100 may be improved. In addition, holes exiting from the second semiconductor layer 150 have high energy and thus can pass through the triangle potential well. Accordingly, the luminous efficiency of the light emitting device 100 can be improved.

4 is a cross-sectional view illustrating a light emitting device according to another embodiment.

The light emitting device 200 according to the embodiment relates to a vertical light emitting device.

Referring to FIG. 4, the light emitting device 200 according to the embodiment includes a support member 210, a first electrode layer 220 disposed on the support member 210, and a light emitting structure disposed on the first electrode layer 220. , And a second electrode layer 282.

The light emitting structure includes a second semiconductor layer 150, an active layer 130 on the second semiconductor layer 150, a first semiconductor layer 120 and a second semiconductor layer 150 and an active layer 130 on the active layer 130. ) May include an intermediate layer 180 positioned at.

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

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

Such a support member 210 facilitates the release of heat generated from the light emitting device 200 to improve thermal stability of the light emitting device 200.

Meanwhile, a first electrode layer 220 may be formed on the support member 210, and the first electrode layer 220 may be an ohmic layer (not shown), a reflective layer (not shown), and a bonding layer. It may include at least one layer of (bonding layer) (not shown). For example, the first electrode layer 220 may have a structure of an ohmic layer/reflective layer/bonding layer, a stacked structure of an ohmic layer/reflective layer, or a reflective layer (including ohmic)/bonding layer, but is not limited thereto. For example, the first electrode layer 220 may have a form in which a reflective layer and an ohmic layer are sequentially stacked on an insulating layer.

The reflective layer (not shown) may be disposed between the ohmic layer (not shown) and the insulating layer (not shown), and a material having excellent reflective properties, for example Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg , Zn, Pt, Au, Hf, and selective combinations thereof, or by using a metal material and a transparent conductive material such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, etc. have. In addition, the reflective layer (not shown) may be laminated with IZO/Ni, AZO/Ag, IZO/Ag/Ni, AZO/Ag/Ni, or the like. In addition, when the reflective layer (not shown) is formed of a material in ohmic contact with the light emitting structure 260 (for example, the second semiconductor layer 150), the ohmic layer (not shown) may not be separately formed, but limited to this I don't.

The ohmic layer (not shown) is in ohmic contact with the lower surface of the light emitting structure, and may be formed as a layer or a plurality of patterns. For the ohmic layer (not shown), a translucent electrode layer and a metal may be selectively used. For example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO). ), 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 /ITO, It can be implemented as a single layer or multiple layers using at least one of Ni, Ag, Ni/IrO _x /Au, and Ni/IrO _x /Au/ITO. The ohmic layer (not shown) is for smoothly injecting carriers into the second semiconductor layer 150 and does not have to be formed.

In addition, the first electrode layer 220 may include a bonding layer (not shown), and in this case, the bonding layer (not shown) is a barrier metal, or a bonding metal such as Ti, Au, Sn, Ni , Cr, Ga, In, Bi, Cu, Ag, and may include at least one of Ta, but is not limited thereto.

The light emitting structure may include at least a first semiconductor layer 120, an active layer 130, and a second semiconductor layer 150, and an active layer 130 between the first semiconductor layer 120 and the second semiconductor layer 150 ) Can be made in the posted configuration.

A second semiconductor layer 150 may be formed on the first electrode layer 220. The second semiconductor layer 150 may be implemented as a p-type semiconductor layer doped with a p-type dopant. The p-type semiconductor layer is 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 GaN, AlN, AlGaN , InGaN, InN, InAlGaN, AlInN, and the like, and p-type dopants such as Mg, Zn, Ca, Sr, Ba, etc. may be doped.

An active layer 130 may be formed on the second semiconductor layer 150. 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 a group 3-5 element.

When the active layer 130 is formed in 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) and In _a Al _b Ga _1-ab N (0≦a≦ ₁ , 0≦b≦ ₁ , 0≦a+b≦1) may have a single or quantum well structure having a barrier layer having a composition formula. The well layer may be formed of a material having a band gap smaller than the band gap of the barrier layer.

A conductive cladding layer (not shown) may be formed above or/or below the active layer 130. The conductive cladding 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.

A first semiconductor layer 120 may be formed on the active layer 130. The first semiconductor layer 120 may be implemented as an n-type semiconductor layer, and the n-type semiconductor layer is, for example, In _x Al _y Ga _1-xy N (0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ x A semiconductor material having a composition formula of +y≤1), for example, can be selected from GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, etc., for example, n such as Si, Ge, Sn, Se, and Te Type dopant may be doped.

A second electrode layer 282 electrically connected to the first semiconductor layer 120 may be formed on the first semiconductor layer 120, and the second electrode layer 282 includes at least one pad or/and an electrode having a predetermined pattern. It may include. The second electrode layer 282 may be disposed in a center region, an outer region, or a corner region of the top surface of the first semiconductor layer 120, but is not limited thereto. The second electrode layer 282 may be disposed in a region other than the first semiconductor layer 120, but is not limited thereto.

The second electrode layer 282 is a conductive material, such as In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, W, Ti, Ag, Cr , Mo, Nb, Al, Ni, Cu, and WTi may be formed in a single layer or multi-layer using a metal or alloy selected from.

A light extraction structure 284 may be formed on the light emitting structure.

The light extracting structure 270 may be formed on the upper surface of the first semiconductor layer 120 or formed on the light-transmitting electrode layer (not shown) after forming a light-transmitting electrode layer (not shown) on the light-emitting structure, It is not limited to this.

The light extracting structure 284 may be formed on a light-transmitting electrode layer (not shown) or on a part or all of the upper surface of the first semiconductor layer 120. 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 first semiconductor layer 120, but is not limited thereto. The etching process includes a wet or/and dry etching process, and according to the etching process, the top surface of the translucent electrode layer (not shown) or the top surface of the first semiconductor layer 120 is rough to form the light extraction structure 284 May contain varnish. The roughness may be irregularly formed with a random size, but is not limited thereto. The roughness is a top surface that is not flat and may include at least one of a texture pattern, an uneven pattern, and an uneven pattern.

The roughness may be formed to have various shapes, such as a side cross section of a cylinder, a polygonal column, a cone, a polygonal pyramid, a truncated cone, and a polygonal pyramid, and preferably includes a horn shape.

Meanwhile, the light extraction structure 284 may be formed by a method such as photo electrochemical (PEC), but is not limited thereto. As the light extraction structure 284 is formed on the translucent electrode layer (not shown) or on the upper surface of the first semiconductor layer 120, the light generated from the active layer 130 is transmitted to the translucent electrode layer (not shown) or the first semiconductor layer Since total reflection from the upper surface of 120 may be prevented from being reabsorbed or scattered, it may contribute to improvement of light extraction efficiency of the light emitting device 200.

The passivation 290 may be formed on the side and upper regions of the light emitting structure, and the passivation 290 may be formed of an insulating material.

The structure of the intermediate layer 180 is the same as described in FIGS. 1 to 3.

5 is a cross-sectional view showing a cross section of a light emitting device package including a light emitting device according to an embodiment.

Referring to FIG. 5, the light emitting device package 300 according to the embodiment includes a body 310 having a cavity, a light source unit 320 mounted in the cavity of the body 310, and an encapsulant 350 filled in the cavity. can do.

The body 310 is made of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), liquid crystal polymer (PSG, photo sensitive glass), polyamide 9T (PA9T). ), neo-geotactic polystyrene (SPS), a metal material, sapphire (Al2O3), beryllium oxide (BeO), a printed circuit board (PCB), and may be formed of at least one of ceramic. The body 310 may be formed by injection molding, an etching process, or the like, but is not limited thereto.

The light source unit 320 is disposed on the bottom surface of the body 310, for example, the light source unit 320 may be any one of the light emitting devices illustrated and described in FIGS. 1 to 5. The light-emitting device may be, for example, a colored light-emitting device that emits red, green, blue, or white light or an ultra violet (UV) light-emitting device that emits ultraviolet rays, but is not limited thereto. In addition, more than one light emitting device may be mounted.

The body 310 may include a first lead frame 330 and a second lead frame 340. The first lead frame 330 and the second lead frame 340 may be electrically connected to the light source unit 320 to supply power to the light source unit 320.

In addition, the first lead frame 330 and the second lead frame 340 are electrically separated from each other, and reflect light generated from the light source unit 320 to increase light efficiency, and also occur in the light source unit 320 Heat can be discharged to the outside.

5 shows that both the first lead frame 330 and the second lead frame 340 are bonded to the light source unit 320 by a wire 360, but the present invention is not limited thereto. In particular, in the case of a vertical light emitting device, Any one of the first lead frame 330 and the second lead frame 340 may be bonded to the light source unit 320 by the wire 360, and the light source unit 320 without the wire 360 by a flip chip method It can also be electrically connected.

The first lead frame 330 and the second lead frame 340 are made of metal, for example, titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chromium (Cr), and tantalum. Nium (Ta), platinum (Pt), tin (Sn), silver (Ag), phosphorus (P), aluminum (Al), indium (In), palladium (Pd), cobalt (Co), silicon (Si), It may include one or more materials or alloys of germanium (Ge), hafnium (Hf), ruthenium (Ru), and iron (Fe). In addition, the first lead frame 330 and the second lead frame 340 may be formed to have a single-layer or multi-layer structure, but are not limited thereto.

The encapsulant 350 may be filled in the cavity and may include a phosphor (not shown). The encapsulant 350 may be formed of transparent silicone, epoxy, and other resin materials, and after filling the cavity, it may be formed by UV or thermal curing.

The type of the phosphor (not shown) may be selected according to the wavelength of light emitted from the light source unit 320 so that the light emitting device package 300 may implement white light.

The phosphor (not shown) included in the encapsulant 350 is a blue light-emitting phosphor, a cyan light-emitting phosphor, a green light-emitting phosphor, a yellow-green light-emitting phosphor, a yellow light-emitting phosphor, a yellow-red light-emitting phosphor, depending on the wavelength of light emitted from the light source unit 320 , An orange light emitting phosphor, and a red light emitting phosphor may be applied.

That is, the phosphor (not shown) may be excited by light having the first light emitted from the light source unit 320 to generate second light. For example, when the light source unit 320 is a blue light-emitting diode and a phosphor (not shown) is a yellow phosphor, the yellow phosphor is excited by blue light to emit yellow light, and blue light and blue light generated from the blue light-emitting diode As yellow light generated by being excited by light is mixed, the light emitting device package 300 may provide white light.

The light emitting device according to the embodiment may be applied to a lighting system. The lighting system includes a structure in which a plurality of light emitting elements are arrayed, and includes the display device shown in FIGS. 6 and 7, the lighting device shown in FIG. 8, and may include a lighting lamp, a traffic light, a vehicle headlight, an electric sign, etc. have.

6 is an exploded perspective view of a display device having a light emitting device according to an exemplary embodiment.

Referring to FIG. 6, a display device 1000 according to an exemplary embodiment includes a light guide plate 1041, a light source module 1031 providing light to the light guide plate 1041, and a reflective member 1022 under the light guide plate 1041. ), an optical sheet 1051 on the light guide plate 1041, a display panel 1061 on the optical sheet 1051, the light guide plate 1041, a light source module 1031, and a reflective member 1022. The bottom cover 1011 may be included, but is not limited thereto.

The bottom cover 1011, the reflective sheet 1022, the light guide plate 1041, and the optical sheet 1051 may be defined as a light unit 1050.

The light guide plate 1041 serves to diffuse light into a surface light source. The light guide plate 1041 is made of a transparent material, for example, acrylic resin series such as PMMA (polymethylmethacrylate), PET (polyethylene terephthalate), PC (polycarbonate), COC (cycloolefin copolymer), and PEN (polyethylene naphtha late). It may contain one of the resins.

The light source module 1031 provides light to at least one side of the light guide plate 1041, and ultimately acts as a light source of the display device.

The light source module 1031 may include at least one, and may directly or indirectly provide light from one side of the light guide plate 1041. The light source module 1031 includes a substrate 1033 and a light emitting device 1035 according to the disclosed embodiment, and the light emitting devices 1035 may be arranged on the substrate 1033 at predetermined intervals. .

The substrate 1033 may be a printed circuit board (PCB) including a circuit pattern (not shown). However, the substrate 1033 may include not only a general PCB, but also a metal core PCB (MCPCB, Metal Core PCB), a flexible PCB (FPCB, Flexible PCB), etc., but is not limited thereto. When the light emitting device 1035 is mounted on a side surface of the bottom cover 1011 or on a heat dissipation plate, the substrate 1033 may be removed. Here, a part of the heat dissipation plate may contact the upper surface of the bottom cover 1011.

In addition, the plurality of light-emitting elements 1035 may be mounted on the substrate 1033 such that an emission surface from which light is emitted is spaced apart from the light guide plate 1041 by a predetermined distance, but the embodiment is not limited thereto. The light-emitting device 1035 may directly or indirectly provide light to a light-incident portion, which is one side of the light guide plate 1041, but is not limited thereto.

The reflective member 1022 may be disposed under the light guide plate 1041. The reflective member 1022 reflects light incident on the lower surface of the light guide plate 1041 and directs it upward, thereby improving the brightness of the light unit 1050. The reflective member 1022 may be formed of, for example, PET, PC, PVC resin, or the like, but is not limited thereto. The reflective member 1022 may be an upper surface of the bottom cover 1011, but is not limited thereto.

The bottom cover 1011 may accommodate the light guide plate 1041, the light source module 1031, and the reflective member 1022. To this end, the bottom cover 1011 may include a receiving portion 1012 having a box shape with an open top surface, but is not limited thereto. The bottom cover 1011 may be coupled to the top cover, but the embodiment is not limited thereto.

The bottom cover 1011 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. In addition, the bottom cover 1011 may include a metal or non-metal material having good thermal conductivity, but is not limited thereto.

The display panel 1061 is, for example, an LCD panel, and includes first and second substrates made of transparent materials facing each other, and a liquid crystal layer interposed between the first and second substrates. A polarizing plate may be attached to at least one surface of the display panel 1061, and the structure of the polarizing plate is not limited thereto. The display panel 1061 displays information by light passing through the optical sheet 1051. The display device 1000 can be applied to various types of portable terminals, monitors of notebook computers, monitors of laptop computers, and televisions.

The optical sheet 1051 is disposed between the display panel 1061 and the light guide plate 1041, and includes at least one translucent sheet. The optical sheet 1051 may include at least one of, for example, a diffusion sheet, a horizontal and vertical prism sheet, and a brightness enhancement sheet. The diffusion sheet diffuses incident light, the horizontal or/and vertical prism sheet condenses incident light to a display area, and the brightness enhancement sheet reuses lost light to improve luminance. In addition, a protective sheet may be disposed on the display panel 1061, but the embodiment is not limited thereto.

Here, as an optical member on the light path of the light source module 1031, the light guide plate 1041 and the optical sheet 1051 may be included, but the embodiment is not limited thereto.

7 is a diagram illustrating a display device having a light emitting device according to an exemplary embodiment.

Referring to FIG. 7, the display device 1100 includes a bottom cover 1152, a substrate 1120 on which the above-described light emitting devices 1124 are arranged, an optical member 1154, and a display panel 1155.

The substrate 1120 and the light emitting device 1124 may be defined as a light source module 1160. The bottom cover 1152, at least one light source module 1160, and the optical member 1154 may be defined as a light unit 1150. The bottom cover 1152 may include an accommodating part 1153, but the embodiment is not limited thereto. The light source module 1160 includes a substrate 1120 and a plurality of light emitting devices 1124 arranged on the substrate 1120.

Here, the optical member 1154 may include at least one of a lens, a light guide plate, a diffusion sheet, a horizontal and vertical prism sheet, and a brightness enhancement sheet. The light guide plate may be made of a PC material or a polymethyl methacrylate (PMMA) material, and the light guide plate may be removed. The diffusion sheet diffuses incident light, the horizontal and vertical prism sheets condense incident light into a display area, and the brightness enhancement sheet reuses lost light to improve brightness.

The optical member 1154 is disposed on the light source module 1160 and performs a surface light source, diffusion, or condensation of light emitted from the light source module 1160.

8 is an exploded perspective view of a lighting device having a light emitting device according to an embodiment.

Referring to FIG. 8, the lighting device according to the embodiment includes a cover 2100, a light source module 2200, a radiator 2400, a power supply unit 2600, an inner case 2700, and a socket 2800. I can. In addition, the lighting device according to the embodiment may further include one or more of a member 2300 and a holder 2500. The light source module 2200 may include a light emitting device according to the embodiment.

For example, the cover 2100 may have a shape of a bulb or a hemisphere, and may be provided in a shape with a hollow and an open portion. The cover 2100 may be optically coupled to the light source module 2200. For example, the cover 2100 may diffuse, scatter, or excite light provided from the light source module 2200. The cover 2100 may be a kind of optical member. The cover 2100 may be coupled to the radiator 2400. The cover 2100 may have a coupling portion coupled to the radiator 2400.

A milky white paint may be coated on the inner surface of the cover 2100. The milky white paint may include a diffuser that diffuses light. The surface roughness of the inner surface of the cover 2100 may be larger than the surface roughness of the outer surface of the cover 2100. This is to allow light from the light source module 2200 to be sufficiently scattered and diffused to be emitted to the outside.

The material of the cover 2100 may be glass, plastic, polypropylene (PP), polyethylene (PE), polycarbonate (PC), or the like. Here, polycarbonate is excellent in light resistance, heat resistance, and strength. The cover 2100 may be transparent or opaque so that the light source module 2200 is visible from the outside. The cover 2100 may be formed through blow molding.

The light source module 2200 may be disposed on one surface of the radiator 2400. Accordingly, heat from the light source module 2200 is conducted to the radiator 2400. The light source module 2200 may include a light emitting device 2210, a connection plate 2230, and a connector 2250.

The member 2300 is disposed on an upper surface of the radiator 2400 and has guide grooves 2310 into which a plurality of light emitting devices 2210 and a connector 2250 are inserted. The guide groove 2310 corresponds to the substrate and the connector 2250 of the light emitting device 2210.

The surface of the member 2300 may be coated or coated with a light reflective material. For example, the surface of the member 2300 may be coated or coated with a white paint. The member 2300 reflects light reflected on the inner surface of the cover 2100 and returning toward the light source module 2200 toward the cover 2100. Therefore, it is possible to improve the light efficiency of the lighting device according to the embodiment.

The member 2300 may be made of an insulating material, for example. The connection plate 2230 of the light source module 2200 may include an electrically conductive material. Accordingly, electrical contact may be made between the radiator 2400 and the connection plate 2230. The member 2300 may be formed of an insulating material to block an electrical short between the connection plate 2230 and the radiator 2400. The radiator 2400 receives heat from the light source module 2200 and heat from the power supply unit 2600 to radiate heat.

The holder 2500 blocks the receiving groove 2719 of the insulating part 2710 of the inner case 2700. Accordingly, the power supply unit 2600 accommodated in the insulating unit 2710 of the inner case 2700 is sealed. The holder 2500 has a guide protrusion 2510. The guide protrusion 2510 may have a hole through which the protrusion 2610 of the power supply unit 2600 passes.

The power supply unit 2600 processes or converts an electrical signal provided from the outside and provides it to the light source module 2200. The power supply unit 2600 is accommodated in the storage groove 2719 of the inner case 2700 and is sealed inside the inner case 2700 by the holder 2500.

The power supply unit 2600 may include a protrusion 2610, a guide part 2630, a base 2650, and a protrusion 2670.

The guide portion 2630 has a shape protruding outward from one side of the base 2650. The guide part 2630 may be inserted into the holder 2500. A number of components may be disposed on one surface of the base 2650. A number of components include, for example, a DC converter for converting AC power provided from an external power source to DC power, a driving chip for controlling the driving of the light source module 2200, and an ESD for protecting the light source module 2200. (ElectroStatic discharge) may include a protection element, but is not limited thereto.

The protrusion 2670 has a shape protruding outward from the other side of the base 2650. The protrusion 2670 is inserted into the connection part 2750 of the inner case 2700 and receives an electrical signal from the outside. For example, the protrusion 2670 may be provided equal to or smaller than the width of the connection part 2750 of the inner case 2700. Each end of the "+ wire" and the "- wire" may be electrically connected to the protrusion 2670, and the other end of the "+ wire" and the "- wire" may be electrically connected to the socket 2800.

The inner case 2700 may include a molding unit together with the power supply unit 2600 therein. The molding part is a part where the molding liquid is solidified, and allows the power supply part 2600 to be fixed inside the inner case 2700.

In addition, although the embodiments have been described above, these are only examples and do not limit the present invention, and those of ordinary skill in the field to which the present invention belongs are illustrated above within the scope not departing from the essential characteristics of the present embodiment. It will be seen that various modifications and applications that are not available are possible. For example, each component specifically shown in the embodiment can be modified and implemented. And differences related to these modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

Claims (10)

A first semiconductor layer;
An active layer disposed on the first semiconductor layer;
A second semiconductor layer disposed on the active layer; And
An intermediate layer disposed between the active layer and the second semiconductor layer and including InAlGaN or AlGaN,
The active layer,
A plurality of well layers; And
And a plurality of barrier layers positioned between the well layers and having a band gap energy greater than that of the well layers,
The intermediate layer,
A first layer adjacent to the active layer and in direct contact with the barrier layer of the active layer; And
And a second layer disposed on the first layer and in direct contact with the first layer and the second semiconductor layer,
Al content of the first layer is greater than the Al content of the second layer,
The first layer is an undoped layer, and the second layer is doped with a dopant having the same polarity as the second semiconductor layer,
The band gap energy of the first layer and the second layer is greater than the band gap energy of the active layer and the second semiconductor layer,
The light emitting device having a band gap energy of the first layer is greater than that of the second layer. delete The method of claim 1,
A light emitting device having a doping concentration of the dopant of the second layer of 5E18 to 5E19 cm ^-3 . delete The method of claim 3,
Al content of the first layer is 15% to 30%,
A light emitting device having an Al content of 10% to 18% in the second layer. The method of claim 3,
The thickness of the first layer is 5nm to 10nm,
The second layer has a thickness of 10 nm to 25 nm. delete delete delete A light emitting device package comprising the light emitting device of any one of claims 1, 3, 5, and 6.

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