KR102473393B1 - Uv light emitting device and lighting system - Google Patents

Abstract

Embodiments relate to a light emitting device, a method for manufacturing a light emitting device, a light emitting device package, and a lighting device.
The light emitting device according to the embodiment includes a second electrode layer 120; a second conductivity type AlGaN-based semiconductor layer 119 on the second electrode layer 120; an active layer 117 disposed on the second conductivity type AlGaN-based semiconductor layer 119; a second AlGaN-based semiconductor layer 116 of a first conductivity type disposed on the active layer 117; a first conductivity type AlGaN series stress relieving layer 115 provided with a predetermined recess (V) and disposed on the first conductivity type second AlGaN series semiconductor layer 116; and a first conductive type first AlGaN based semiconductor layer 114 disposed on the first conductive type AlGaN based stress relieving layer 115 .

Description

UV light emitting device and lighting system {UV LIGHT EMITTING DEVICE AND LIGHTING SYSTEM}

Embodiments relate to an ultraviolet light emitting device, a method for manufacturing a light emitting device, a light emitting device package, and a lighting device.

A light emitting device (Light Emitting Device) can be produced by combining a group 3-5 element or a group 2-6 element on the periodic table with a p-n junction diode that has the characteristic of converting electrical energy into light energy, and the composition ratio of compound semiconductors It is possible to achieve various colors by adjusting.

For example, nitride semiconductors are of great interest in the field of developing optical devices and high-power electronic devices due to their high thermal stability and wide bandgap energy. In particular, ultraviolet (UV) light emitting devices, blue light emitting devices, green light emitting devices, red (RED) light emitting devices, and the like using nitride semiconductors are commercialized and widely used.

For example, in the case of an ultraviolet light emitting device, as a light emitting device that generates light distributed in a wavelength range of 200 nm to 400 nm, in the wavelength range, in the case of a short wavelength, it is used for sterilization and purification, and in the case of a long wavelength, an exposure machine or a curing machine, etc. can be used

For example, near UV LEDs are used for counterfeiting, resin curing, or ultraviolet treatment, and are also used in lighting devices that implement visible light of various colors in combination with phosphors.

On the other hand, the UV light emitting device has a problem in that light acquisition efficiency and light output are lower than that of the blue light emitting device. This acts as a barrier to the practical use of ultraviolet light emitting devices.

For example, group Ⅲ nitrides used in ultraviolet light emitting devices can be widely used from visible light to ultraviolet light, but there is a problem in that the efficiency of ultraviolet light is lowered compared to visible light. The reason for this is that Group III nitrides absorb ultraviolet rays as the wavelength of ultraviolet rays increases, and internal quantum efficiency decreases due to low crystallinity.

Accordingly, according to the prior art, in order to prevent UV absorption in group III nitrides, after sequentially growing a growth substrate, a GaN layer, an AlGaN layer, an active layer, etc., the GaN layer with the possibility of UV absorption is removed and the AlGaN layer is exposed. However, it is difficult to solve the problem of lowering the internal quantum efficiency due to the low crystallinity of the AlGaN layer.

For example, according to the prior art, when an AlGaN layer is grown on a GaN layer, tensile stress is generated in the AlGaN layer due to a difference in lattice constant, etc., and cracks occur, resulting in leakage current and lowering light output ( Po) has a problem.

In addition, according to the prior art, when cracks are generated by tensile stress in the AlGaN layer, there is a problem in that luminous flux is lowered due to crystal quality degradation due to crack transfer to the light emitting layer.

In addition, according to the prior art, a light extraction structure is formed by texturing. When an AlGaN layer is grown on a GaN layer, it is difficult to form an AlGaN layer thick due to a difference in lattice constant. It is difficult to form a light extraction structure by the light extraction efficiency is reduced.

On the other hand, since the UV LED is not originally in the visible ray region, UV is invisible, but violet light is emitted by a tail corresponding to a wavelength other than the main peak, that is, a long wavelength.

Violet light from the tail is mixed with yellow luminescence in the 550nm to 560nm region caused by the above-mentioned point defects, and color difference such as purple-white-yellow may occur in one wafer. Such a color difference may cause emotional deterioration.

Embodiments are intended to provide an ultraviolet light emitting device with improved light output, a method for manufacturing a light emitting device, a light emitting device package, and a lighting system.

Embodiments are intended to provide an ultraviolet light emitting device with improved luminous flux according to the improvement of crystal quality, a method for manufacturing a light emitting device, a light emitting device package, and a lighting system.

In addition, embodiments are intended to provide an ultraviolet light emitting device with improved light extraction efficiency, a method for manufacturing a light emitting device, a light emitting device package, and a lighting system.

In addition, embodiments are intended to provide an ultraviolet light emitting device capable of improving color difference, a method for manufacturing a light emitting device, a light emitting device package, and a lighting system.

The light emitting device according to the embodiment includes a second electrode layer 120; a second conductivity type AlGaN-based semiconductor layer 119 on the second electrode layer 120; an active layer 117 disposed on the second conductivity type AlGaN-based semiconductor layer 119; a second AlGaN-based semiconductor layer 116 of a first conductivity type disposed on the active layer 117; a first conductivity type AlGaN series stress relieving layer 115 provided with a predetermined recess (V) and disposed on the first conductivity type second AlGaN series semiconductor layer 116; and a first conductive type first AlGaN based semiconductor layer 114 disposed on the first conductive type AlGaN based stress relieving layer 115 .

In addition, the light emitting device according to the embodiment includes a second electrode layer 120; a second conductivity type AlGaN-based semiconductor layer 119 on the second electrode layer 120; an active layer 117 disposed on the second conductivity type AlGaN-based semiconductor layer 119; a second AlGaN-based semiconductor layer 116 of a first conductivity type disposed on the active layer 117; a first conductivity type AlGaN series stress relieving layer 115 disposed on the first conductivity type second AlGaN series semiconductor layer 116; and a second light extraction pattern R2 disposed on the first conductive AlGaN-based stress relieving layer 115 .

A lighting device according to an embodiment may include a light emitting unit having the light emitting element.

Embodiments may provide an ultraviolet light emitting device with improved light output, a method for manufacturing a light emitting device, a light emitting device package, and a lighting system.

Embodiments may provide an ultraviolet light emitting device with improved luminous flux according to the improvement of crystal quality, a method for manufacturing a light emitting device, a light emitting device package, and a lighting system.

In addition, embodiments may provide an ultraviolet light emitting device with improved light extraction efficiency, a method for manufacturing a light emitting device, a light emitting device package, and a lighting system.

In addition, embodiments may provide an ultraviolet light emitting device capable of improving color difference, a method for manufacturing a light emitting device, a light emitting device package, and a lighting system.

1 is a cross-sectional view of an ultraviolet light emitting device according to a first embodiment.
2 is a cross-sectional view of an ultraviolet light emitting device according to a second embodiment.
3 to 7 are cross-sectional views of a manufacturing method of a light emitting device according to an embodiment.
8 is a cross-sectional view of a light emitting device package according to an embodiment.
9 is a perspective view of a lighting device according to an embodiment;

In the description of the 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 where it is described as being formed in, "on/over" and "under" include both "directly" or "indirectly" formed through another layer. do. In addition, the criterion for the top/top or bottom of each layer is described based on the drawings, but the embodiment is not limited thereto.

(Example)

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

The ultraviolet light emitting device 100 according to the embodiment includes a second electrode layer 120, a second conductive AlGaN-based semiconductor layer 119, an active layer 117, a first conductive second AlGaN-based semiconductor layer 116, It may include a 1 conductivity type AlGaN series stress relieving layer 115 , a first conductivity type first AlGaN series semiconductor layer 114 , and a first electrode 131 . The second electrode layer 120 may include a contact layer 122 , a reflective layer 124 and a conductive support member 126 . A first light extraction pattern R1 may be formed on the first AlGaN-based semiconductor layer 114 of the first conductivity type.

For example, the light emitting device 100 according to the embodiment includes a second electrode layer 120, a second conductive AlGaN-based semiconductor layer 119 on the second electrode layer 120, and the second conductive AlGaN An active layer 117 disposed on the series semiconductor layer 116, a second AlGaN-based semiconductor layer 116 of a first conductivity type disposed on the active layer 117, and a predetermined recess V A first conductivity-type AlGaN-based stress relieving layer 115 disposed on the first conductive second AlGaN-based semiconductor layer 116 and a first conductive AlGaN-based stress relieving layer 115 disposed on the first conductive-type AlGaN-based stress relieving layer 115 A conductive first AlGaN-based semiconductor layer 114 may be included.

Embodiments are intended to provide an ultraviolet light emitting device with improved light output, an ultraviolet light emitting device with improved luminous flux due to improved crystal quality, or an ultraviolet light emitting device with improved light extraction efficiency.

On the other hand, according to the prior art, when the AlGaN layer is grown on the GaN layer, there is a problem in that cracks occur due to tensile stress generated in the AlGaN layer due to a difference in lattice constant.

In this embodiment, the AlGaN-based stress relieving layer 115 is disposed between the first conductive-type first AlGaN-based semiconductor layer 114 and the first-conductive second AlGaN-based semiconductor layer 116. It is possible to prevent cracks from occurring by relieving the stress applied to the semiconductor layer.

For example, in the embodiment, the first AlGaN-based semiconductor layer 114 is formed on the GaN-based first conductivity-type semiconductor layer 112 (see FIG. 3), and then the first AlGaN-based semiconductor layer 114 is formed. A first conductivity-type AlGaN-based stress relieving layer 115 having a predetermined recess V may be formed thereon.

The first conductivity-type AlGaN-based stress relieving layer 115 responds to threading dislocation generated between the first conductivity-type semiconductor layer 112, which is a lower GaN-based semiconductor layer, and the first AlGaN-based semiconductor layer 114. It can be formed in a V shape (Shape) by, but is not limited thereto.

In the embodiment, the first conductivity-type AlGaN-based stress relieving layer 115 relieves tensile stress between the first conductivity-type semiconductor layer 112, which is an existing GaN-based layer, and the AlGaN-based layer, thereby reducing the second When the AlGaN-based semiconductor layer 116 is formed, cracks are prevented from occurring, thereby suppressing leakage current, thereby providing an ultraviolet light emitting device having excellent electrical reliability and improved light output (Po).

In addition, according to the embodiment, by relieving Tensile Stress between the first conductivity-type semiconductor layer 112 and the AlGaN-based layer by the first conductivity-type AlGaN-based stress relieving layer 115, the second AlGaN-based stress relieving layer 115 is used. When the semiconductor layer 116 is formed, cracks are generated, and as crystal quality is improved, an ultraviolet light emitting device having improved luminous flux may be provided.

Also, in the embodiment, the recess V formed in the AlGaN-based stress relieving layer 115 may have a narrower width toward the upper side, but is not limited thereto. External light extraction efficiency may be improved by light scattering by the recess V.

In the embodiment, the composition of Al of the first conductivity-type first AlGaN-based semiconductor layer 114 is set lower than the composition of Al of the second first-conductivity-type AlGaN-based semiconductor layer 116, so that the first conductivity-type first By minimizing the difference between the AlGaN-based semiconductor layer 114 and the first conductivity-type semiconductor layer 112, which is a GaN-based layer, and Al composition, the lattice constant difference is reduced, thereby reducing the possibility of stress relaxation and cracking, thereby improving electrical reliability and optical reliability. It can improve the output and increase the luminous flux.

For example, in an embodiment, the first AlGaN-based semiconductor layer 114 of the first conductivity type may have a composition of Al _x1 Ga _{1 - x1} N (where 0≤≤x1≤≤1), and the first conductivity type The second AlGaN-based semiconductor layer 116 may have a composition of Al _x2 Ga _{1 - x2} N (where 0≤≤x2≤1). In this case, in the embodiment, the composition (x1) of Al in the first AlGaN-based semiconductor layer 114 of the first conductivity type may be 3% to 5%, and in the second AlGaN-based semiconductor layer 116 of the first conductivity type The composition (x2) of Al may be 6% to 8%, but is not limited thereto. When the Al composition is less than about 3%, light emitted from the active layer 117 is absorbed and light output is reduced.

Accordingly, according to the embodiment, the Al composition of the first conductive type first AlGaN-based semiconductor layer 114 is set lower than the Al composition of the first conductive type second AlGaN-based semiconductor layer 116, so that the lattice constant By reducing the difference, it is possible to improve electrical reliability, improve light output, and increase luminous flux by reducing the possibility of stress relaxation and crack generation.

In addition, according to the embodiment, the composition of Al in the first conductivity-type AlGaN-based stress relieving layer 115 is higher than the composition of Al in the first conductivity-type first AlGaN-based semiconductor layer 114, and the first conductivity-type AlGaN-based stress relieving layer 115 The Al composition of the second AlGaN-based semiconductor layer 116 may be higher.

The first conductive AlGaN-based stress relieving layer 115 may have a composition of Al _x3 Ga _{1 - x3} N (where 0≤≤x3≤≤1), and the first conductive AlGaN-based stress relieving layer 115 ), the composition (x3) of Al may be 8% to 10%, and accordingly, the composition (x3) of Al in the first conductivity type AlGaN-based stress relieving layer 115 is the first AlGaN of the first conductivity type. The first conductivity type AlGaN series stress relieving layer is set higher than the Al composition (x1) of the series semiconductor layer 114 and higher than the Al composition (x2) of the first conductivity type second AlGaN series semiconductor layer 116. By inducing and eliminating the occurrence of dislocation D (see FIG. 3) in (115), it can contribute to improving crystal quality and electrical characteristics.

Hereinafter, a mechanism for preventing cracks from occurring in the second AlGaN-based semiconductor layer 116 of the first conductivity type will be described in more detail.

According to the embodiment, the first conductivity-type AlGaN-based stress relieving layer 115 having a higher Al composition than the first-conductivity second AlGaN-based semiconductor layer 116 is intentionally inserted to intentionally misfit dislocations in the 11-20 direction (Misfit Dislocation). Dislocation (D) is created to relieve the existing stress, and the first conductivity type AlGaN series stress is relieved by the first conductivity type second AlGaN series first semiconductor layer 116a grown in 3D mode Cracks caused by the insertion of the layer 115 are filled to suppress generation of cracks during the growth of the second AlGaN-based semiconductor layer 116 of the first conductivity type and simultaneously improve crystal quality.

According to the embodiment, cracks generated by the AlGaN-based stress relieving layer 115 having a higher Al composition are partially filled by patterns of the second AlGaN-based first semiconductor layer 116a of the first conductivity type, and the crack is Since the non-occurring portion is the AlGaN-based stress relieving layer 115 region having a high Al composition, the lattice constant is small, and the second AlGaN-based semiconductor layer 116 of the first conductivity type having a low Al concentration, which is then grown thickly, has a tensile stress. Because it is subjected to compressive stress rather than tensile stress, generation of cracks in the first conductive second AlGaN-based semiconductor layer 116 can be suppressed.

In an embodiment, the thickness of the first conductivity-type AlGaN-based stress relieving layer 115 may be greater than that of the first conductive-type first AlGaN-based semiconductor layer 114 . For example, the first conductivity-type first AlGaN-based semiconductor layer 114 may be formed with a thickness of about 1.0 μm to less than 2.0 μm, and the first conductivity-type AlGaN-based stress relieving layer 115 may have a thickness of greater than 2.0 μm to less than 2.0 μm. It may be formed to 4.0 μm. In general, when the thickness of the AlGaN-based semiconductor layer is less than about 2.0 μm, a lot of cracks occur.

Accordingly, according to the embodiment, dislocation (D) is induced in the first AlGaN-based semiconductor layer 114 and absorbed in the V-shape recess (V) of the first conductive AlGaN-based stress relieving layer 115 By quenching, crystal quality can be improved to improve optical and electrical properties.

~약400

더 낮은 온도에서 성장됨에 따라 결정성장 속도 저하에 따라 V-Shape 형태의 리세스(V) 형성이 잘 되어 디스로케이션(D)의 흡수 소멸의 효율을 증대시킬 수 있다.In the embodiment, the first conductivity-type AlGaN-based stress relieving layer 115 is lower than the growth temperature of the first conductive-type first AlGaN-based semiconductor layer 114, for example, about 300

~about 400

As grown at a lower temperature, the formation of a recess (V) in the form of a V-shape is well formed according to the decrease in the crystal growth rate, thereby increasing the absorption and extinction efficiency of the dislocation (D).

Embodiments are intended to provide an ultraviolet light emitting device with an improved color difference.

According to the embodiment, yellow luminescence increases as the thickness of the AlGaN-based semiconductor layer increases, but it does not increase in linear proportion, and the gradient gradually decreases, resulting in saturation.

The first conductive second AlGaN-based semiconductor layer 116 may include a first conductive second AlGaN-based first semiconductor layer 116a and a first conductive second AlGaN-based second semiconductor layer 116b. have.

In an embodiment, the Al composition of the first conductivity type second AlGaN series first semiconductor layer 116a may be different from the Al composition of the first conductivity type second AlGaN series second semiconductor layer 116b. For example, the Al composition of the first conductivity type second AlGaN series first semiconductor layer 116a may be greater than the Al composition of the first conductivity type second AlGaN series second semiconductor layer 116b.

For example, the Al composition of the first conductivity type second AlGaN-based second semiconductor layer 116b may be about 3% to about 5%, and its thickness may be about 5 nm to about 15 nm. If the Al composition of the second AlGaN-based second semiconductor layer 116b of the first conductivity type is less than 3%, light absorption may occur, and if it exceeds 5%, it may not contribute to improving color gamut.

In an embodiment, when the thickness of the second AlGaN-based second semiconductor layer 116b of the first conductivity type is less than 5 nm, there may be no color difference improvement effect, and when the thickness exceeds 15 nm, light loss due to light absorption may occur.

In addition, the Al composition of the first conductivity-type second AlGaN-based first semiconductor layer 116a may be greater than the Al composition of the first conductivity-type second AlGaN-based second semiconductor layer 116b and may be about 8% or less. have. For example, if the Al composition of the first conductivity-type second AlGaN-based first semiconductor layer 116a is lower than the Al composition of the first-conductivity second AlGaN-based second semiconductor layer 116b, light absorption may occur. Optical loss may occur, and if it exceeds 8%, quality may be deteriorated.

The maximum thickness of the first conductive second AlGaN-based first semiconductor layer 116a may be thicker than that of the first conductive second AlGaN-based second semiconductor layer 116b and may be about 30 nm or less.

When the thickness of the first conductive second AlGaN-based first semiconductor layer 116a is smaller than the thickness of the first conductive second AlGaN-based second semiconductor layer 116b, an effect of improving color difference may be deteriorated. , If the thickness is about 30 nm or more, cracks may occur and quality may deteriorate.

The embodiment may be applied to a vertical UV light emitting device. For example, the light emitting structure 110 is disposed on the second electrode layer 120, and the first AlGaN-based semiconductor layer 114 of the first conductivity type is interposed with a predetermined light-transmitting electrode layer (not shown). One electrode 131 may be disposed.

The light-transmitting electrode layer includes indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO Nitride), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO) to include at least one of may be, but is not limited to these materials.

The embodiment is Al _x In _y Ga _(1-xy) N (0≤≤x≤≤1,0≤≤y≤ disposed between the second conductivity type AlGaN-based semiconductor layer 119 and the active layer 117 ≤1) series semiconductor layer (not shown). The Al _x In _y Ga _(1-xy) N (0≤≤x≤≤1,0≤≤y≤≤1) series semiconductor layer may function as an electron blocking layer, but is not limited thereto.

Meanwhile, the UV light emitting device according to the embodiment may be applied to a horizontal type UV light emitting device.

2 is a cross-sectional view of a light emitting element 102 according to a second embodiment.

The second embodiment may employ the technical features of the first embodiment, and the main features of the second embodiment will be mainly described below.

The light emitting device 102 according to the second embodiment includes a second electrode layer 120, a second conductive AlGaN-based semiconductor layer 119 on the second electrode layer 120, and the second conductive AlGaN-based semiconductor. An active layer 117 disposed on the layer 116, a second AlGaN-based semiconductor layer 116 of a first conductivity type disposed on the active layer 117, and a second AlGaN-based semiconductor layer of the first conductivity type ( 116) and a second light extraction pattern R2 disposed on the first conductive AlGaN-based stress relieving layer 115 and the first conductive AlGaN-based stress relieving layer 115.

The second embodiment may include a second light extraction pattern R2 disposed on the first conductive type AlGaN-based stress relieving layer 115 . Also, the second embodiment may include a protrusion P on the first conductive second AlGaN-based semiconductor layer 116 . The second light extraction pattern R2 may be formed by patterning the first conductive AlGaN-based stress relieving layer 115, but is not limited thereto.

In the second embodiment, the first conductivity type AlGaN-based stress relieving layer 115 may be formed to a thickness of about 100 nm to about 300 nm. When the thickness of the first conductive AlGaN-based stress relieving layer 115 is less than about 100 nm, the crack release effect may be reduced, and when the thickness exceeds 300 nm, the first conductive second AlGaN-based semiconductor layer formed thereafter The crystallinity of (116) may be lowered.

According to the second embodiment, the light output (Po) can be improved by including the protrusion (P) on the upper side of the first conductivity type second AlGaN-based semiconductor layer 116 to improve external light extraction efficiency.

In addition, the second embodiment includes the second light extraction pattern R2 disposed on the first conductive type AlGaN-based stress relieving layer 115 to increase light output by improving light extraction efficiency. Accordingly, the embodiment can provide an ultraviolet light emitting device with improved light extraction efficiency.

Hereinafter, a method of manufacturing an ultraviolet light emitting device according to an embodiment will be described with reference to FIGS. 3 to 7 . Hereinafter, description will be made based on the first embodiment, but the manufacturing method of the embodiment is not limited thereto.

First, a substrate 105 is prepared as shown in FIG. 3 . 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 sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, and Ga ₂ 0 ₃ At least one of them can be used. A concavo-convex structure may be formed on the substrate 105, but is not limited thereto.

A buffer layer (not shown) may be formed on the substrate 105 . The buffer layer can mitigate the lattice mismatch between the material of the light emitting structure 110 and the substrate 105 to be formed later, and the material of the buffer layer is a Group 3-5 or Group 2-6 compound semiconductor such as GaN and InN. , AlN, InGaN, AlGaN, InAlGaN, may be formed of at least one of AlInN.

Next, a first conductivity type semiconductor layer 112 may be formed on the first substrate 105 . For example, the first conductivity type semiconductor layer 112 may be implemented with a compound semiconductor such as group 3-5 or group 2-6, and may be doped with a first conductivity type dopant.

When the first conductivity-type semiconductor layer 112 is an n-type semiconductor layer, the first conductivity-type dopant is an n-type dopant and may include Si, Ge, Sn, Se, or Te, but is not limited thereto.

The first conductivity-type semiconductor layer 112 may be a GaN-based semiconductor layer, In _x Al _y Ga _{1 -x- y} N (0≤≤x≤≤1, 0≤≤y≤≤1, 0≤≤x +y≤≤1) may include a semiconductor material having a composition formula. For example, the first conductivity-type semiconductor layer 112 is formed of one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP, and InP. It can be.

Next, a first conductivity-type AlGaN-based first semiconductor layer 114 may be formed on the first conductivity-type semiconductor layer 112, and then a first conductivity-type AlGaN-based stress relieving layer 115 may be formed. can

In addition, as shown in FIG. 4 , a first conductivity type AlGaN series second semiconductor layer 116 may be formed on the first conductivity type AlGaN series stress relieving layer 115 .

In an embodiment, the first AlGaN-based semiconductor layer 114 of the first conductivity type may have a composition of Al _x1 Ga _{1 - x1} N (where 0≤≤x1≤1), and the first conductivity-type AlGaN-based stress relieving layer. (115) may have a composition of Al _x3 Ga _{1 - x3} N (where 0≤≤x3≤≤1), and the second AlGaN-based semiconductor layer 116 of the first conductivity type is Al _x2 Ga _{1 - x2} N (However, 0≤≤x2≤≤1) may be provided.

~약400

더 낮은 온도에서 성장됨에 따라 결정성장 속도 저하에 따라 V-Shape 형태의 리세스(V) 형성이 잘 되어 디스로케이션(D)의 흡수 소멸의 효율을 증대시킬 수 있다.In the embodiment, the first conductivity-type AlGaN-based stress relieving layer 115 is lower than the growth temperature of the first conductive-type first AlGaN-based semiconductor layer 114, for example, about 300

~about 400

As grown at a lower temperature, the formation of a recess (V) in the form of a V-shape is well formed according to the decrease in the crystal growth rate, thereby increasing the absorption and extinction efficiency of the dislocation (D).

In the embodiment, the first conductive type AlGaN-based stress relieving layer 115 is disposed between the first AlGaN-based semiconductor layer 114 and the second AlGaN-based semiconductor layer 116 formed thereafter, so that the stress applied to the AlGaN-based semiconductor layer can be relieved to prevent cracking.

For example, in the embodiment, after forming the first AlGaN-based semiconductor layer 114 on the GaN-based first conductivity-type semiconductor layer 112, a predetermined recess is formed on the first AlGaN-based semiconductor layer 114. A first conductivity type AlGaN-based stress relieving layer 115 having (V) may be formed.

The first conductive AlGaN-based stress relieving layer 115 is formed by threading dislocation generated between the first conductive semiconductor layer 112, which is a lower GaN-based semiconductor layer, and the first AlGaN-based semiconductor layer 114 ( D) can be formed in a V shape (Shape), but is not limited thereto.

In the embodiment, the first conductivity-type AlGaN-based stress relieving layer 115 relieves tensile stress between the first conductivity-type semiconductor layer 112, which is an existing GaN-based layer, and the AlGaN-based layer, thereby reducing the second When the AlGaN-based semiconductor layer 116 is formed, cracks are prevented from occurring, thereby suppressing leakage current, thereby providing an ultraviolet light emitting device having excellent electrical reliability and improved light output (Po).

In addition, according to the embodiment, by relieving Tensile Stress between the first conductivity-type semiconductor layer 112 and the AlGaN-based layer by the first conductivity-type AlGaN-based stress relieving layer 115, the second AlGaN-based stress relieving layer 115 is used. When the semiconductor layer 116 is formed, cracks are generated, and as crystal quality is improved, an ultraviolet light emitting device having improved luminous flux may be provided.

Also, in the embodiment, the recess V formed in the AlGaN-based stress relieving layer 115 may have a narrower width toward the upper side, but is not limited thereto. External light extraction efficiency may be improved by light scattering by the recess V.

In the embodiment, the composition of Al of the first conductivity-type first AlGaN-based semiconductor layer 114 is set lower than the composition of Al of the second first-conductivity-type AlGaN-based semiconductor layer 116, so that the first conductivity-type first By minimizing the difference between the AlGaN-based semiconductor layer 114 and the first conductivity-type semiconductor layer 112, which is a GaN-based layer, and Al composition, the lattice constant difference is reduced, thereby reducing the possibility of stress relaxation and cracking, thereby improving electrical reliability and optical reliability. It can improve the output and increase the luminous flux.

For example, in an embodiment, the first AlGaN-based semiconductor layer 114 of the first conductivity type may have a composition of Al _x1 Ga _{1 - x1} N (where 0≤≤x1≤≤1), and the first conductivity type The second AlGaN-based semiconductor layer 116 may have a composition of Al _x2 Ga _{1 - x2} N (where 0≤≤x2≤1). In this case, in the embodiment, the composition (x1) of Al in the first AlGaN-based semiconductor layer 114 of the first conductivity type may be 3% to 5%, and in the second AlGaN-based semiconductor layer 116 of the first conductivity type The composition (x2) of Al may be 6% to 8%, but is not limited thereto. When the Al composition is less than about 3%, light emitted from the active layer 117 is absorbed and light output is reduced.

Accordingly, according to the embodiment, the Al composition of the first conductive type first AlGaN-based semiconductor layer 114 is set lower than the Al composition of the first conductive type second AlGaN-based semiconductor layer 116, so that the lattice constant By reducing the difference, it is possible to improve electrical reliability, improve light output, and increase luminous flux by reducing the possibility of stress relaxation and crack generation.

In addition, according to the embodiment, the composition of Al in the first conductivity-type AlGaN-based stress relieving layer 115 is higher than the composition of Al in the first conductivity-type first AlGaN-based semiconductor layer 114, and the first conductivity-type AlGaN-based stress relieving layer 115 It may be lower than the Al composition of the second AlGaN-based semiconductor layer 116.

In an embodiment, the thickness of the first conductivity-type AlGaN-based stress relieving layer 115 may be greater than that of the first conductive-type first AlGaN-based semiconductor layer 114 . For example, the first conductivity-type first AlGaN-based semiconductor layer 114 may be formed with a thickness of about 1.0 μm to less than 2.0 μm, and the first conductivity-type AlGaN-based stress relieving layer 115 may have a thickness of greater than 2.0 μm to less than 2.0 μm. It may be formed to 4.0 μm. In general, when the thickness of the AlGaN-based semiconductor layer is less than about 2.0 μm, a lot of cracks occur.

Accordingly, according to the embodiment, dislocation (D) is induced in the first AlGaN-based semiconductor layer 114 and absorbed in the V-shape recess (V) of the first conductive AlGaN-based stress relieving layer 115 By quenching, crystal quality can be improved to improve optical and electrical properties.

The first conductive second AlGaN-based semiconductor layer 116 may include a first conductive second AlGaN-based first semiconductor layer 116a and a first conductive second AlGaN-based second semiconductor layer 116b. And, through this, it is intended to provide an ultraviolet light emitting device having an improved color difference.

In an embodiment, the Al composition of the first conductivity type second AlGaN series first semiconductor layer 116a may be different from the Al composition of the first conductivity type second AlGaN series second semiconductor layer 116b. For example, the Al composition of the first conductivity type second AlGaN series first semiconductor layer 116a may be greater than the Al composition of the first conductivity type second AlGaN series second semiconductor layer 116b.

For example, the Al composition of the first conductivity type second AlGaN-based second semiconductor layer 116b may be about 3% to about 5%, and its thickness may be about 5 nm to about 15 nm. If the Al composition of the second AlGaN-based second semiconductor layer 116b of the first conductivity type is less than 3%, light absorption may occur, and if it exceeds 5%, it may not contribute to improving color gamut.

In an embodiment, when the thickness of the second AlGaN-based second semiconductor layer 116b of the first conductivity type is less than 5 nm, there may be no color difference improvement effect, and when the thickness exceeds 15 nm, light loss due to light absorption may occur.

In addition, the Al composition of the first conductivity-type second AlGaN-based first semiconductor layer 116a may be greater than the Al composition of the first conductivity-type second AlGaN-based second semiconductor layer 116b and may be about 8% or less. have. For example, if the Al composition of the first conductivity-type second AlGaN-based first semiconductor layer 116a is lower than the Al composition of the first-conductivity second AlGaN-based second semiconductor layer 116b, light absorption may occur. Optical loss may occur, and if it exceeds 8%, quality may be deteriorated.

The first conductivity-type second AlGaN-based first semiconductor layer 116a may have a thickness greater than that of the first-conductivity second AlGaN-based second semiconductor layer 116b and may be about 30 nm or less.

When the thickness of the first conductive second AlGaN-based first semiconductor layer 116a is smaller than the thickness of the first conductive second AlGaN-based second semiconductor layer 116b, an effect of improving color difference may be deteriorated. , If the thickness is about 30 nm or more, cracks may occur and quality may deteriorate.

Hereinafter, a mechanism for preventing cracks from occurring in the second AlGaN-based semiconductor layer 116 of the first conductivity type will be described in more detail.

According to the embodiment, misfit dislocation in the 11-20 direction is achieved by inserting the first conductivity type AlGaN series stress relieving layer 115 having a higher Al composition than the first conductivity type second AlGaN series semiconductor layer 116. (D) is generated to relieve the existing stress, and the first conductivity type AlGaN series stress relieving layer (by the first conductivity type second AlGaN series first semiconductor layer 116a grown in 3D mode) 115) It is possible to suppress generation of cracks during the growth of the second AlGaN-based semiconductor layer 116 of the first conductivity type by filling in cracks caused by the insertion and simultaneously improve crystal quality.

The cracks generated by the AlGaN-based stress relieving layer 115 having a higher Al composition are partially filled by the patterns of the second AlGaN-based first semiconductor layer 116a of the first conductivity type. Since it is the AlGaN-based stress relieving layer 115 region having a high Al composition, the lattice constant is small, and the second AlGaN-based semiconductor layer 116 of the first conductivity type having a low Al concentration, which is then grown thickly, has a tensile stress. Rather, since it is subjected to compressive stress, generation of cracks in the first conductive second AlGaN-based semiconductor layer 116 can be suppressed.

Next, as shown in FIG. 5 , an active layer 117 and a second conductive AlGaN-based semiconductor layer 119 may be formed on the first conductive second AlGaN-based semiconductor layer 116 .

The active layer 117 may be formed of at least one of a single quantum well structure, a multi quantum well (MQW) structure, a quantum wire structure, or a quantum dot structure.

For example, the active layer 117 may be injected with trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) to form a multi-quantum well structure. It is not limited to this.

The active layer 117 may include a quantum well and a quantum wall. For example, the active layer 117 has a pair structure of one or more of AlGaN/GaN, AlGaN/AlGaN, InGaN/GaN, InGaN/InGaN, InAlGaN/GaN, GaAs/AlGaAs, InGaAs/AlGaAs, GaP/AlGaP, and InGaP AlGaP. It may be formed, but is not limited thereto.

The second conductivity-type AlGaN-based semiconductor layer 119 may be implemented with a semiconductor compound, for example, a compound semiconductor of Group 3-5 or Group 2-6, and may be doped with a second conductivity type dopant. .

For example, the second conductivity type AlGaN-based semiconductor layer 119 may include a semiconductor material having a composition formula of Al _q Ga _{1 - q} N (0≤≤q≤≤1). When the second conductive AlGaN-based semiconductor layer 119 is a p-type semiconductor layer, the second conductive dopant is a p-type dopant and may include Mg, Zn, Ca, Sr, Ba, or the like.

In an embodiment, the first conductive second AlGaN-based semiconductor layer 116 may be implemented as an n-type semiconductor layer, and the second conductive-type AlGaN-based semiconductor layer 119 may be implemented as a p-type semiconductor layer, but is not limited thereto.

In addition, a semiconductor having a polarity opposite to that of the second conductivity type, for example, an n-type semiconductor layer (not shown) may be formed on the second conductivity type AlGaN-based semiconductor layer 119 . Accordingly, the light emitting structure 110 may be implemented with any one of an n-p junction structure, a p-n junction structure, an n-p-n junction structure, and a p-n-p junction structure.

Next, a second electrode layer 120 may be formed on the second conductivity type AlGaN-based semiconductor layer 119 . The second electrode layer 120 may include a contact layer 122 , a reflective layer 124 , and a conductive support member 126 .

The contact layer 122 may be formed by stacking a single metal, metal alloy, or metal oxide in multiple layers so as to efficiently perform carrier injection. For example, the contact layer 122 may be formed of a material having excellent electrical contact with a semiconductor.

For example, the contact layer 122 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), and IGTO. (indium gallium 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, and may be formed including at least one of Hf, but is not limited to these materials.

A reflective layer 124 may be formed on the contact layer 122 . The reflective layer 124 may be formed of a material having excellent reflectivity and excellent electrical contact. For example, the reflective layer 124 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 124 may be formed in multiple layers using the metal or alloy and a light-transmitting conductive material such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, and the like. For example, IZO/Ni, AZO /Ag, IZO/Ag/Ni, AZO/Ag/Ni, etc. can be laminated.

Next, a conductive support member 126 may be formed on the reflective layer 124 .

The conductive support member 126 may be made of metal, metal alloy, or conductive semiconductor material having excellent electrical conductivity so as to efficiently inject carriers. For example, the conductive support member 126 may include copper (Cu), gold (Au), copper alloy (Cu Alloy), nickel (Ni-nickel), copper-tungsten (Cu-W), a carrier wafer (eg, GaN, Si, Ge, GaAs, ZnO, SiGe, SiC, etc.) and the like may be optionally included.

As a method of forming the conductive support member 126, an electrochemical metal deposition method or a bonding method using a eutectic metal may be used.

Next, as shown in FIG. 6 , the substrate 105 may be removed from the light emitting structure 110 . For example, as a method of removing the substrate 105, a high power laser may be used to separate the substrate or a chemical etching method may be used. In addition, the substrate 105 may be removed by physically grinding it.

For example, in the laser lift-off method, when a predetermined energy is applied at room temperature, the energy is absorbed at the interface between the substrate 105 and the light emitting structure, and the bonding surface of the light emitting structure is thermally decomposed to separate the substrate 105 and the light emitting structure. can do.

Next, as shown in FIG. 7 , the first conductivity type semiconductor layer 112 may be removed by wet etching or dry etching, so that the first AlGaN-based semiconductor layer 114 of the first conductivity type may be exposed. Thereafter, a first light extraction pattern R1 may be formed on the first conductive type first AlGaN-based semiconductor layer 114, and the first light extraction pattern R1 may be a regular pattern or an irregular pattern or a combination thereof. It may be a mixture, but is not limited thereto.

In an embodiment, the first light extraction pattern R1 has a predetermined horizontal width on the first AlGaN-based semiconductor layer 114 of the first conductivity type, and the first AlGaN-based semiconductor layer 114 of the first conductivity type ) can be formed of the same material.

Next, a first electrode 131 may be formed on the first AlGaN-based semiconductor layer 114 of the first conductivity type, and through this, an ultraviolet light emitting device according to an embodiment may be manufactured. The first electrode 131 may be formed of a metal or alloy including at least one of Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf.

UV light emitting devices are divided into UV-A ((315 ~ 400nm)), UV-B (280 ~ 315nm), and UV-C (200 ~ 280nm) in order of the longest wavelength.

According to the embodiment, according to the wavelength, the UV-A (315 ~ 400nm) area is industrial UV curing, printing ink curing, exposure machine, counterfeiting, photocatalyst sterilization, special lighting (aquarium / agricultural, etc.) ), UV-B (280 ~ 315nm) can be used for medical purposes, and UV-C (200 ~ 280nm) can be applied to air purification, water purification, sterilization products, etc.

A plurality of light emitting devices according to the embodiment may be arrayed on a substrate in the form of a package, and optical members such as a light guide plate, a prism sheet, a diffusion sheet, a fluorescent sheet, and the like may be disposed on a path of light emitted from the light emitting device package.

The light emitting device according to the embodiment may be applied to a backlight unit, a lighting unit, a display device, an indicator device, a lamp, a street light, a vehicle lighting device, a vehicle display device, a smart watch, etc., but is not limited thereto.

For example, FIG. 8 is a diagram illustrating a light emitting device package 200 in which light emitting devices according to embodiments are installed.

The light emitting device package according to the embodiment is installed on the package body 205, the third electrode layer 213 and the fourth electrode layer 214 installed on the package body 205, and the package body 205, A light emitting element 100 electrically connected to the third electrode layer 213 and the fourth electrode layer 214 and a molding member 230 surrounding the light emitting element 100 are included.

The third electrode layer 213 and the fourth electrode layer 214 are electrically separated from each other and serve to provide power to the light emitting element 100 . In addition, the third electrode layer 213 and the fourth electrode layer 214 may serve to increase light efficiency by reflecting light generated from the light emitting device 100, and It can also play a role in dissipating heat to the outside.

The light emitting device 100 may be electrically connected to the third electrode layer 213 and/or the fourth electrode layer 214 by any one of a wire method, a flip chip method, and a die bonding method.

The light emitting device 100 may be an ultraviolet light emitting device according to the first embodiment, but is not limited thereto, and may include a light emitting device 102 according to the second embodiment.

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

9 is an exploded perspective view of a lighting system according to an embodiment.

The lighting device according to the embodiment may include a cover 2100, a light source module 2200, a heat sink 2400, a power supply 2600, an inner case 2700, and a socket 2800. In addition, the lighting device according to the embodiment may further include any one or more of the member 2300 and the holder 2500 . The light source module 2200 may include a light emitting device or a light emitting device package according to an embodiment.

The light source module 2200 may include a light source unit 2210, a connection plate 2230, and a connector 2250. The member 2300 is disposed on the top surface of the radiator 2400 and has guide grooves 2310 into which a plurality of light source units 2210 and a connector 2250 are inserted.

The holder 2500 blocks the receiving groove 2719 of the insulating part 2710 of the inner case 2700. Thus, the power supply unit 2600 accommodated in the insulation unit 2710 of the inner case 2700 is sealed. The holder 2500 has a guide protrusion 2510 .

The power supply unit 2600 may include a protrusion 2610, a guide unit 2630, a base 2650, and an extension unit 2670. The inner case 2700 may include a molding part together with the power supply part 2600 therein. The molding part is a part where the molding liquid is hardened, and allows the power supply part 2600 to be fixed inside the inner case 2700 .

Features, structures, effects, etc. described in the embodiments above are included in at least one embodiment, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, and effects illustrated in each embodiment can be combined or modified with respect to other embodiments by those skilled in the art in the field to which the embodiments belong. Therefore, contents related to these combinations and modifications should be construed as being included in the scope of the embodiments.

Although the above has been described centering on the embodiment, this is only an example and does not limit the embodiment, and those skilled in the art in the field to which the embodiment belongs may find various things not exemplified above to the extent that they do not deviate from the essential characteristics of the embodiment. It will be appreciated that variations and applications of branches 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 embodiments set forth in the appended claims.

The second electrode layer 120, the contact layer 122, the reflective layer 124,
A conductive support member 126, a second conductive AlGaN-based semiconductor layer 119, an active layer 117,
A first conductive second AlGaN-based semiconductor layer 116, a first conductive AlGaN-based stress relieving layer 115,
A first conductive type first AlGaN-based semiconductor layer 114, a first electrode 131, and a first light extraction pattern R1

Claims (15)

a second electrode layer;
a second conductivity type AlGaN-based semiconductor layer on the second electrode layer;
an active layer disposed on the second conductivity type AlGaN-based semiconductor layer;
a second AlGaN-based semiconductor layer of a first conductivity type disposed on the active layer;
a first conductivity type AlGaN series stress relieving layer disposed on the first conductivity type second AlGaN series semiconductor layer; and
A first conductive type first AlGaN-based semiconductor layer disposed on the first conductive type AlGaN-based stress relieving layer;
The Al composition of the first conductivity-type first AlGaN-based semiconductor layer is lower than the Al composition of the first conductivity-type second AlGaN-based semiconductor layer;
The Al composition of the first conductivity-type AlGaN-based stress relieving layer is higher than the Al composition of the first conductive-type first AlGaN-based semiconductor layer,
The Al composition of the first conductive AlGaN-based stress relieving layer is higher than the Al composition of the first conductive second AlGaN-based semiconductor layer. According to claim 1,
The composition of Al of the first conductivity-type first AlGaN-based semiconductor layer is 3% to 5%,
The composition of Al of the first conductivity-type second AlGaN-based semiconductor layer is 6% to 8% UV light emitting device. According to claim 1,
The first conductivity type AlGaN-based stress relieving layer includes a predetermined recess,
The recess is disposed on a surface facing the second AlGaN-based semiconductor layer of the first conductivity type,
The recess is an ultraviolet light emitting device in which a width becomes narrower toward an upper side of the first conductive type AlGaN-based stress relieving layer. According to claim 1,
The first conductivity type second AlGaN-based semiconductor layer is
An ultraviolet light emitting device comprising a first conductivity type second AlGaN-based first semiconductor layer and a first conductivity type second AlGaN-based second semiconductor layer. According to claim 1,
The thickness of the first conductivity-type AlGaN-based stress relieving layer is
An ultraviolet light emitting device thicker than the thickness of the first conductive type first AlGaN-based semiconductor layer. A lighting system comprising a light emitting unit having the light emitting device of any one of claims 1 to 5. delete delete delete delete delete delete delete delete delete

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