KR102322696B1 - Uv light emitting device and light emitting device package - Google Patents

Abstract

The embodiment relates to an ultraviolet light emitting device, a method for manufacturing an ultraviolet light emitting device, a light emitting device package, and a lighting device.
An ultraviolet light emitting device according to an embodiment includes a first conductivity type semiconductor layer, a plurality of quantum walls, and a plurality of quantum wells, an active layer disposed on the first conductivity type semiconductor layer, and a second conductivity layer disposed on the active layer type semiconductor layer, each of the plurality of quantum wells includes a plurality of first and second quantum wells, and the second quantum well is an In _x2 Al _y Ga _1-x2-y N layer (0.01≤x2≤0.04, 0.03≤y≤0.085, 0≤x2+y≤1).

Description

UV light emitting device and light emitting device package {UV LIGHT EMITTING DEVICE AND LIGHT EMITTING DEVICE PACKAGE}

The embodiment relates to an ultraviolet light emitting device, a method for manufacturing an ultraviolet light emitting device, a light emitting device package, and a lighting device.

Light Emitting Diode is a pn junction diode with the characteristic that electric energy is converted into light energy, and can be created with compound semiconductors such as Group III and V on the periodic table, and various colors can be realized by adjusting the composition ratio of the compound semiconductor. possible.

Nitride semiconductors are receiving great attention in the field of developing optical devices and high-power electronic devices due to their high thermal stability and wide bandgap energy. In particular, an ultraviolet (UV) light emitting device, a blue light emitting device, a green light emitting device, and a red (RED) light emitting device using a nitride semiconductor have been commercialized and widely used.

The ultraviolet light emitting device (UV LED) is a light emitting device that emits light in a wavelength range of 200 nm to 400 nm. The ultraviolet light emitting device is composed of a short wavelength and a long wavelength depending on the use. The short wavelength may be used for sterilization or purification, and the long wavelength may be used for an exposure machine or a curing machine.

On the other hand, the light emitting device according to the prior art has a droop problem in that the luminous efficiency is lowered when the amount of injection current is increased, which is a problem that occurs because the injection efficiency of carriers (holes or electrons) into the light emitting layer is not uniform. In order to solve this problem, it is required to develop a technology capable of allowing most of the quantum wells of the light emitting layer to substantially participate in light emission.

In addition, in the case of an ultraviolet light emitting device, a technology capable of increasing luminous efficiency is required considering that the composition of indium (In) in the quantum well is lower than that of a conventional light emitting device in the visible region such as a blue light emitting device. do.

The embodiment may provide an ultraviolet light emitting device capable of improving luminous efficiency, a method for manufacturing an ultraviolet light emitting device, a light emitting device package, and a lighting device.

The embodiment may provide an ultraviolet light emitting device capable of improving luminous intensity, a method for manufacturing an ultraviolet light emitting device, a light emitting device package, and a lighting device.

The ultraviolet light emitting device according to the embodiment includes a first conductive semiconductor layer 112; an active layer 114 including a plurality of quantum walls 114B and a plurality of quantum wells 114W and disposed on the first conductivity-type semiconductor layer 112; and a second conductivity-type semiconductor layer 112 disposed on the active layer 114, wherein each of the plurality of quantum wells 114W includes a plurality of first and second quantum wells 114W1 and 114W2, , the second quantum well 114W2 may include an In _x2 Al _y Ga _1-x2-y N layer (0.01≤x2≤0.04, 0.03≤y≤0.085, 0≤x2+y≤1).

The light emitting device package according to the embodiment may include the ultraviolet light emitting device.

The ultraviolet light emitting device of the embodiment can improve the luminous efficiency while maintaining the volume of the entire quantum well.

The ultraviolet light emitting device of the embodiment can improve the luminous intensity while maintaining the volume of the entire quantum well.

1 is a cross-sectional view illustrating an ultraviolet light emitting device according to an embodiment.
2 is a diagram illustrating a band diagram of a light emitting device according to an embodiment.
3 to 6 are views illustrating a method of manufacturing an ultraviolet light emitting device according to an embodiment.
7 is a cross-sectional view illustrating a light emitting device package according to an embodiment.

In the description of an embodiment, each layer (film), region, pattern or structure is “on/over” or “under” the substrate, each layer (film), region, pad or pattern. In the case of being described as being formed on, “on/over” and “under” include both “directly” or “indirectly” formed through another layer. do. In addition, the criteria for the upper / upper or lower of each layer will be described with reference to the drawings.

1 is a cross-sectional view illustrating an ultraviolet light emitting device according to an embodiment.

1 , the ultraviolet light emitting device 100 according to the embodiment may include a light emitting structure 110 .

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

The first conductivity type semiconductor layer 112 may be located on the active layer 114 , and the second conductivity type semiconductor layer 116 may be located below the active layer 114 .

The ultraviolet light emitting device 114 of the embodiment may include a first electrode 150 positioned on the first conductivity-type semiconductor layer 114 .

The ultraviolet light emitting device 100 of the embodiment may include a current blocking layer 161 , a channel layer 163 , and a second electrode 170 under the light emitting structure 110 .

The second electrode 170 may include a contact layer 165 , a reflective layer 167 , and a bonding layer 169 .

The ultraviolet light emitting device 100 of the embodiment may be a horizontal type light emitting device in which the first electrode 150 is positioned on the light emitting structure 110 and the second electrode 170 is positioned under the light emitting structure 110, but is limited thereto. However, it may be applied to a horizontal type light emitting device in which all electrodes are disposed on an upper portion of the light emitting structure.

2 is a diagram illustrating a band diagram of a light emitting device according to an embodiment.

As shown in FIG. 2 , the light emitting device according to the embodiment may include an active layer 114 positioned between the first and second conductivity-type semiconductor layers 112 and 116 . Here, an electron blocking layer 122 may be disposed between the active layer 114 and the second conductivity type semiconductor layer 116 , but is not limited thereto.

The active layer 114 may include a plurality of quantum walls 114B and a plurality of quantum wells 114W.

The plurality of quantum wells 114W may include a plurality of first quantum wells 114W1 and a plurality of second quantum wells 114W2. The plurality of first and second quantum wells 114W1 and 114W2 may be two or more pairs, but is not limited thereto. For example, the plurality of first and second quantum wells 114W1 and 114W2 may be 2 to 10 pairs. The plurality of first and second quantum wells 114W1 and 114W2 may have bandgap energies similar to each other. That is, the first and second quantum wells 114W1 and 114W2 may have the same bandgap energy, but is not limited thereto.

The plurality of first quantum wells 114W1 may include an In _x1 Ga _1-x1 N layer (0≤x1≤1). The plurality of first quantum wells 114W1 may have an indium (In) composition of 0.01, but is not limited thereto. The plurality of first quantum wells 114W1 may fill pits that are increased by aluminum (Al) of the plurality of second quantum wells 114W2 . Here, the plurality of first quantum wells 114W1 may fill the pit to improve the reduction in luminous efficiency due to the pit. The last layer of each of the quantum wells 114W may be the first quantum well 114W1, but is not limited thereto. For example, the first quantum well 114W1 may be in contact with the quantum wall 114B.

The plurality of second quantum wells 114W2 may include an In _x2 Al _y Ga _1-x2-y N layer (0.01≤x2≤0.04, 0.03≤y≤0.085, 0≤x2+y≤1). The plurality of second quantum wells 114W2 may have an indium (In) composition of 0.01 to 0.04, but is not limited thereto. The plurality of second quantum wells 114W2 may have an aluminum (Al) composition of 0.03 to 0.085, but is not limited thereto. In the plurality of second quantum wells 114W2, indium (In) included in the quantum wells 114W, including an aluminum (Al) composition, aggregates with each other, so that luminous efficiency may be improved.

When the indium (In) composition of the plurality of second quantum wells 114W2 is less than 0.01 and the aluminum (Al) composition is less than 0.03, the aggregation effect of indium (In) by the aluminum (Al) composition is reduced, so that the luminous efficiency is lowered. may be lowered. When the indium (In) composition of the plurality of second quantum wells 114W2 exceeds 0.04 and the aluminum (Al) composition exceeds 0.085, the crystallinity decreases due to the indium (In) composition and the fit by the aluminum (Al) composition The increase may decrease the luminous intensity Po.

The ultraviolet light emitting device of the embodiment maintains the volume of the entire quantum well 114W, and each quantum well 114W includes the first quantum well 114W1 of the _{In x1} Ga _{1-x1 N layer (0≤x1≤1) and} In _x2 Al _y Ga _1-x2-y N layer (0.01 ≤ x2 ≤ 0.04, 0.03 ≤ y ≤ 0.085, 0 ≤ x2 + y ≤ 1) of the second quantum wells 114W2 are formed in two or more pairs to increase the luminous efficiency. can be improved That is, in the embodiment, the luminous efficiency can be improved by the indium (In) aggregation effect by the second quantum well 114W2 containing indium (In) and aluminum (Al), and the second quantum well 114W2 Since the pit generated by the quantum well 114W1 is relaxed by the first quantum well 114W1, the luminous efficiency can be improved while maintaining the volume of the entire quantum well 114W.

3 to 6 are views illustrating a method of manufacturing an ultraviolet light emitting device according to an embodiment.

Referring to FIG. 3 , the buffer layer 106 may be formed on the substrate 105 .

The substrate 105 may be formed of a material having excellent thermal conductivity, and may be a conductive substrate or an insulating substrate. For example, the substrate 105 may include at least one _{of sapphire (Al 2} O ₃ ), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, and Ga ₂ 0 _{3 .} A concave-convex structure may be formed on the substrate 105 , but the present invention is not limited thereto.

The buffer layer 106 reduces the difference in lattice constant between the substrate 105 and the nitride semiconductor layer, and the material thereof is GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP. , AlGaInP may be selected. For example, the buffer layer 106 may be undoped GaN, but is not limited thereto.

The buffer layer 106 may be at least one. That is, the buffer layer 106 may be a plurality of layers of two or more.

Referring to FIG. 4 , the light emitting structure 110 including the first conductivity type semiconductor layer 112 , the active layer 114 , and the second conductivity type semiconductor layer 116 may be formed on the buffer layer 106 . .

The first conductivity type semiconductor layer 112 may be implemented with a semiconductor compound, for example, a compound semiconductor such as group II-VI or group III-V, and may be doped with a first conductivity type dopant. For example, the first conductivity type semiconductor layer 112 may include a semiconductor material having a composition formula _{of Al n} Ga _{1-n N (0≤n≤1).} When the first conductivity-type semiconductor layer 112 is an n-type semiconductor layer, the n-type dopant may include Si, Ge, Sn, Se, and Te, but is not limited thereto.

The active layer 114 may be formed on the first conductivity-type semiconductor layer 112 , and the active layer 114 may adopt the technical characteristics of the embodiment of FIG. 2 .

In the active layer 114 , electrons (or holes) injected through the first conductivity type semiconductor layer 112 and holes (or electrons) injected through the second conductivity type semiconductor layer 116 meet each other, and the This is a layer that emits light due to a difference in the band gap of an energy band according to the material forming the active layer 114 .

The active layer 114 may be formed of a compound semiconductor. The active layer 114 may be implemented, for example, by at least one of a group II-IV group and a group III-V compound semiconductor.

The active layer 114 may include a quantum well and a quantum wall. When the active layer 114 has a multi-quantum well structure, quantum wells and quantum walls may be alternately disposed. Referring to FIG. 2 , the quantum well 114W includes a _{first quantum well 114W1 of an In x1} Ga _1-x1 N layer (0≤x1≤1) and an In _x2 Al _y Ga _1-x2-y N layer ( Two or more pairs of second quantum wells 114W2 of 0.01≤x2≤0.04, 0.03≤y≤0.085, and 0≤x2+y≤1 may be formed. In the embodiment, the luminous efficiency is improved by the indium (In) aggregation effect by the second quantum well 114W2 containing indium (In) and aluminum (Al), and the pit generated by the second quantum well 114W2 is relaxed by the first quantum well 114W1, so that the luminous efficiency can be improved while maintaining the volume of the entire quantum well.

Referring back to FIG. 4 , the second conductivity-type semiconductor layer 116 may be implemented with a semiconductor compound, for example, a group II-IV and group III-V compound semiconductor, and may be doped with a second conductivity-type dopant. have. For example, the second conductivity type semiconductor layer 116 may include a semiconductor material having a composition formula _{of Al p} Ga _{1-p N (0≤p≤1).} When the second conductivity-type semiconductor layer 116 is a p-type semiconductor layer, the second conductivity-type dopant is a p-type dopant and may include Mg, Zn, Ca, Sr, Ba, or the like.

The first conductivity-type semiconductor layer 112 may be formed of a p-type semiconductor layer, and the second conductivity-type semiconductor layer 116 may be formed of an n-type semiconductor layer, but is not limited thereto.

Referring to FIG. 5 , in the ultraviolet light emitting device of the embodiment, a current blocking layer 161 , a channel layer 163 , and a second electrode 170dl may be formed under the light emitting structure 110 .

The current blocking layer 161 may _{include at least one of SiO 2} , SiO _x , SiO _x N _y , Si ₃ N ₄ , Al ₂ O ₃ , and TiO ₂ , the light emitting structure 110 and the second electrode ( 170) may be formed between at least one.

The current blocking layer 161 is disposed to correspond to the first electrode 150 disposed on the light emitting structure 110 in the thickness direction of the light emitting structure 110 . The current blocking layer 161 may block the current supplied from the second electrode 170 and spread it to another path.

The channel layer 163 is formed along the periphery of the lower surface of the second conductivity-type AlGaN-based semiconductor layer 116 and may be formed in a ring shape, a loop shape, or a frame shape. The channel layer 163 is at least one of ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, SiO ₂ , SiO _x , SiO _x N _y , Si ₃ N ₄ , Al ₂ O ₃ , TiO ₂ may include An inner portion of the channel layer 163 may be disposed under the second conductivity-type AlGaN-based semiconductor layer 116 , and an outer portion of the channel layer 163 may be disposed more outside than a side surface of the light emitting structure 110 .

The second electrode 170 may include a contact layer 165 , a reflective layer 167 , and a bonding layer 169 .

The contact layer 165 may be formed by stacking a single metal, a metal alloy, or a metal oxide in multiple layers to efficiently inject carriers. The contact layer 165 may be formed of an excellent material that is in electrical contact with the semiconductor. For example, the contact layer 165 may include indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), or indium gallium (IGTO). tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO Nitride), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), ZnO, IrOx , RuOx, NiO, RuOx/ITO, Ni/IrOx/Au, and Ni/IrOx/Au/ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, It may be formed including at least one of Hf, but is not limited thereto.

The reflective layer 167 may be positioned on the contact layer 165 . The reflective layer 167 may be formed of a material having excellent reflectivity and excellent electrical contact. For example, the reflective layer 167 may be formed of a metal or alloy including at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf.

In addition, the reflective layer 167 may be formed as a single layer or a multi-layer using the metal or alloy and a light-transmitting conductive material such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, and ATO, for example, IZO/Ni, AZO/ It can be laminated with Ag, IZO/Ag/Ni, AZO/Ag/Ni, or the like.

A bonding layer 169 is formed under the reflective layer 167, and the bonding layer 169 may be used as a barrier metal or a bonding metal, and the material is, for example, Ti, Au, Sn, Ni, Cr, at least one of Ga, In, Bi, Cu, Ag, and Ta and an optional alloy.

A support member 173 is formed under the bonding layer 169 , and the support member 173 may be formed of a conductive member, and the material is copper (Cu-copper), gold (Au-gold), or nickel. It may be formed of a conductive material such as (Ni-nickel), molybdenum (Mo), copper-tungsten (Cu-W), or a carrier wafer (eg, Si, Ge, GaAs, ZnO, SiC, etc.). As another example, the support member 173 may be implemented as a conductive sheet.

Referring to FIG. 6 , the substrate 105 and the buffer layer 106 may be removed from the light emitting structure 110 . For example, a method of removing the substrate 105 and the buffer layer 106 may use a chemical etching method.

A light extraction pattern 119 for improving light extraction efficiency may be formed on the first conductivity-type semiconductor layer 112 exposed by removing the substrate 105 and the buffer layer 106 . The light extraction pattern 119 may be formed by a method such as PEC, but is not limited thereto. The light extraction pattern 119 may be formed to have a regular shape and arrangement, or may be formed to have an irregular shape and arrangement.

The light extraction pattern 119 may improve light extraction efficiency by refracting the light generated from the active layer 114 to the outside.

The ultraviolet light emitting device of the embodiment may include the first electrode 150 .

The first electrode 150 may be positioned on the first conductivity-type semiconductor layer 112 .

Although the ultraviolet light emitting device of the embodiment is described as a vertical type, the electrodes may be applied to a horizontal type positioned on the upper surface of the light emitting structure 110 .

7 is a cross-sectional view illustrating a light emitting device package according to an embodiment.

The light emitting device package 200 according to the embodiment includes a package body part 205 , the first lead electrodes 213 and second lead electrodes 214 installed on the package body part 205 , and the package body part ( The UV light emitting device 100 installed in 205 and electrically connected to the first lead electrode 213 and the second lead electrode 214, and a molding member 230 surrounding the UV light emitting device 100 are provided. Included.

The first lead electrode 213 and the second lead electrode 214 are electrically isolated from each other, and serve to provide power to the ultraviolet light emitting device 100 . In addition, the first lead electrode 213 and the second lead electrode 214 may include a function of increasing light efficiency by reflecting the light emitted from the UV light emitting device 100, and the UV light emitting device ( 100) may include a function of discharging the generated heat to the outside.

The ultraviolet light emitting device 100 may be electrically connected to the first lead electrode 213 or the second lead electrode 214 by any one of a wire method, a flip chip method, or a die bonding method.

The ultraviolet light emitting device 100 may employ the technical features of FIGS. 1 to 6 .

The molding member 230 may include a phosphor 232 to form a white light emitting device package, but is not limited thereto.

The upper surface of the molding member 230 may be flat, concave, or convex, but is not limited thereto.

Features, structures, effects, etc. described in the above embodiments are included in at least one embodiment, and are not necessarily limited to only one embodiment. Furthermore, features, structures, effects, etc. illustrated in each embodiment can be combined or modified for other embodiments by those of ordinary skill in the art to which the embodiments belong. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the embodiments.

In the above, the embodiment has been mainly described, but this is only an example and not limiting the embodiment, and those of ordinary skill in the art to which the embodiment pertains are provided with several examples not illustrated above in the range that does not depart from the essential characteristics of the embodiment. It can be seen that variations and applications of branches are possible. For example, each component specifically shown in the embodiment can be implemented by modification. And differences related to such modifications and applications should be construed as being included in the scope of the embodiments set forth in the appended claims.

114B: quantum wall 114W: quantum well
114W1: first quantum well 114W2: second quantum well

Claims (8)

a first conductivity type semiconductor layer;
an active layer including a plurality of quantum walls and a plurality of quantum wells, the active layer disposed under the first conductivity-type semiconductor layer; and
A second conductivity type semiconductor layer disposed under the active layer,
Each of the plurality of quantum wells includes a plurality of first and second quantum wells,
The first quantum well includes an In _x1 Ga _1-x1 N layer (0≤x1≤1),
The second quantum well includes an In _x2 Al _y Ga _1-x2-y N layer (0.01≤x2≤0.04, 0.03≤y≤0.085, 0≤x2+y≤1),
The last layer of each of the plurality of quantum wells in contact with the quantum wall is the first quantum well. The method of claim 1,
In the first quantum well, x1 is 0.01 of an ultraviolet light emitting device. The method of claim 1,
The plurality of first and second quantum wells are two or more pairs of ultraviolet light emitting devices. The method of claim 1,
The plurality of first and second quantum wells are an ultraviolet light emitting device having the same bandgap energy. A light emitting device package comprising the ultraviolet light emitting device of any one of claims 1 to 4. delete delete delete

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