KR20170001138A - Uv light emitting device, light emitting device package and lighting device - Google Patents

Abstract

The present invention relates to a UV light emitting device, a manufacturing method thereof, a light emitting device package and a lighting device. The UV light emitting device comprises: a substrate; a first undoped GaN layer including an upper flat side and a V fit on the substrate; a first nitride layer placed on the V fit of the first undoped GaN layer; a first undoped AlGaN-based semiconductor layer placed in the first GaN undoped layer and the first nitride layer; a second undoped GaN layer placed in the first undoped AlGaN-based semiconductor layer. The first undoped AlGaN-based semiconductor layer comprises a first part placed on the upper flat side of the first undoped GaN layer and a second part placed in the V fit of the first undoped GaN layer, and an AI composition rate of the first part can be higher than of the second part.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a UV light emitting device, a light emitting device package,

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

A light emitting device can be formed by combining a group III-V element or a group II-VI element in the periodic table with a pn junction diode in which electrical energy is converted into light energy, Various colors can be realized by adjusting.

Nitride semiconductors have attracted great interest in the development of optical devices and high output electronic devices due to their high thermal stability and wide band gap energy. Particularly, ultraviolet (UV) light emitting elements, blue light emitting elements, green light emitting elements, and red light emitting elements using nitride semiconductors are commercially available 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 has a short wavelength and a long wavelength depending on the application. The short wavelength may be used for sterilization or purification, and the long wavelength may be used for an exposure machine, a curing machine, or the like.

On the other hand, the ultraviolet light-emitting device has a problem that the light-receiving efficiency and the light output are lower than that of the blue light-emitting device. This serves as a barrier to practical use of the ultraviolet light emitting element.

For example, a group III nitride used in an ultraviolet light emitting device can be widely used from visible light to ultraviolet light, but the efficiency of ultraviolet light compared to visible light is inferior. The reason is that Group III nitride absorbs ultraviolet rays toward the wavelength of ultraviolet rays and degradation of internal quantum efficiency due to low crystallinity.

Since the In composition of the ultraviolet light emitting device is low, it is difficult to see the localization effect of In compared to the blue LED in the quantum well. Therefore, in the prior art, the control and crystallinity of the threading dislocation coming from the lower layer affects the brightness of the chip.

Embodiments can provide an ultraviolet light emitting device, a method of manufacturing an ultraviolet light emitting device, a light emitting device package, and a lighting device having improved brightness in accordance with an improvement in crystal quality.

In addition, embodiments can provide an ultraviolet light emitting device, a method of manufacturing an ultraviolet light emitting device, a light emitting device package, and a lighting device improved in defect and improved in brightness.

An ultraviolet light-emitting device according to an embodiment includes a substrate 105; A first undoped GaN layer 106a including a flat top surface and V-pits V on the substrate 105; A first nitride layer 107 disposed on a V-pit (V) of the first undoped GaN layer 106a; A first undoped AlGaN-based semiconductor layer 108 disposed on the first undoped GaN layer 106a and the first nitride layer 107; And a second undoped GaN layer (106b) located on the first undoped AlGaN-based semiconductor layer (108), wherein the first undoped AlGaN-based semiconductor layer (108) comprises a first undoped GaN layer (V) of the first undoped GaN layer (106a) and a second region (108b) located on a flat top surface of the first undoped GaN layer (106a)

The Al composition of the first region 108a may be larger than the Al composition of the second region 108b.

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

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

The embodiment can improve the crystal quality of the light emitting structure, thereby improving the brightness of the ultraviolet light emitting element.

Further, the embodiment can improve the luminous intensity of the ultraviolet light-emitting element by improving defects of the light-emitting structure.

1 is a cross-sectional view illustrating an ultraviolet light-emitting device according to an embodiment.
FIG. 2 is a cross-sectional view showing the degree of defects of an ultraviolet light-emitting device including the undoped AlGaN-based semiconductor layer of FIG. 1;
3 to 7 are cross-sectional views illustrating a method of manufacturing an ultraviolet light-emitting device according to an embodiment.
8 is a cross-sectional view illustrating an ultraviolet light-emitting device according to another embodiment.
9A and 9B are photographs of TD density comparison of Comparative Examples and Experimental Examples.
10 is a cross-sectional view illustrating a light emitting device package according to an embodiment.

In the description of the embodiments, it is to be understood that each layer (film), area, pattern or structure may be referred to as being "on" or "under" the substrate, each layer Quot; on "and" under "are intended to include both" directly "or" indirectly " do. Also, the criteria for top, bottom, or bottom of each layer will be described with reference to the drawings.

FIG. 1 is a cross-sectional view illustrating an ultraviolet light-emitting device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view illustrating the degree of defects of an ultraviolet light-emitting device including the undoped AlGaN-based semiconductor layer of FIG.

1 and 2, the ultraviolet light emitting device 100 includes a first undoped GaN layer 106a, a nitride layer 107, an undoped AlGaN-based semiconductor layer 108, a second undoped GaN layer Lt; RTI ID = 0.0 > 106b. ≪ / RTI >

The first undoped GaN layer 106a may be located on the substrate 105. [ The first undoped GaN layer 106a may be at least one or more. For example, the first undoped GaN layer 106a may be a plurality of two or more layers. The first undoped GaN layer 106a may have a plurality of V pits V by controlling a growth temperature or growth pressure. For example, the first undoped GaN layer 106a can lower the mobility of Ga by controlling the growth temperature or the growth pressure, and thus the first undoped GaN layer 106a including roughness ) Can be formed. For example, the first undoped GaN layer 106a may be formed such that at least a portion thereof has a side surface or a top surface, and the side surfaces may include a plurality of V pits V. The roughness may be formed regularly or irregularly, but is not limited thereto.

The nitride layer 107 may be located within the V-pits V. The nitride layer 107 may be formed at a lower end of the V-pit V. The nitride layer 107 may include SiNx (x> 0), but is not limited thereto. The nitride layer 107 may be formed at the V pits V of the first undoped GaN layer 106a to improve defects occurring at the lower end of the V pits V. [ For example, the nitride layer 107 is formed of an amorphous material and is formed at the lower end of the V-pit V of the first undoped GaN layer 106a so that a dislocation occurring at the lower end of the V-pit V 2 undoped GaN layer 106b can be reduced, and the path through which the defect propagates can be bended. The nitride layer 107 may be located on the upper surface of the first undoped GaN layer 106a in addition to the bottom of the V-pit V, but is not limited thereto.

The undoped AlGaN-based semiconductor layer 108 may be located on the nitride layer 107. The undoped AlGaN-based semiconductor layer 108 may be in direct contact with the nitride layer 107. The undoped AlGaN-based semiconductor layer 108 may be grown on the upper surface and the side surface (V-pit side) of the first undoped GaN layer 106a. The undoped AlGaN-based semiconductor layer 108 has a first region 108a located on the upper surface of the first undoped GaN layer 106a and a second region 108b located on the upper surface of the first undoped GaN layer 106a, And a second region 108b positioned on top of the second region 108b. The growth rate of the undoped AlGaN-based semiconductor layer 108 may be slower than that of the first region 108a and the second region 108b. As a result, the Al concentration of the undoped AlGaN-based semiconductor layer 108 can be relatively larger in the first region 108a than in the second region 108b. That is, since the Al concentration is larger in the first region 108a than in the second region 108b, the binding energy of AlGaN in the first region 108a becomes larger than that in the second region 108b, The defect propagating to the second undoped GaN layer 106b can be reduced because the defect propagating at the lower end of the second undoped GaN layer 106b is bent into the second region 108b rather than the first region 108a.

The undoped AlGaN-based semiconductor layer 108 may include a semiconductor material having a composition formula of Al _x Ga _1-x N (0.4 _{? X} ? 0.8). If the Al composition x of the undoped AlGaN-based semiconductor layer 108 is less than 0.4, the dislocation blocking of the first region 108a may be reduced. If the Al composition x of the undoped AlGaN-based semiconductor layer 108 is more than 0.8, the effect of dislocation bending in the second region 108b may be deteriorated.

The thickness of the undoped AlGaN-based semiconductor layer 108 may be 50 nm or more. For example, the thickness of the undoped AlGaN-based semiconductor layer 108 may be 5 nm to 15 nm. If the thickness of the undoped AlGaN-based semiconductor layer 108 is less than 5 nm, the defect blocking of the first region 108a may be lowered and the defect bending effect of the second region 108b may be lowered . When the thickness of the undoped AlGaN-based semiconductor layer 108 is more than 15 nm, crystallinity may be deteriorated due to a high lattice constant due to a high composition.

The second undoped GaN layer 106b may be located on the undoped AlGaN-based semiconductor layer 108. [ The thickness of the second undoped GaN layer 106b may be 800 nm or more. For example, the thickness of the second undoped GaN layer 106b may be 800 nm to 1500 nm. If the thickness of the second undoped GaN layer 106b is less than 800 nm, the defect bending effect may be deteriorated.

The ultraviolet light emitting device 100 of the embodiment may include the light emitting structure 110. The light emitting structure 110 may be located on the second undoped GaN layer 106b. The light emitting structure 110 may be in direct contact with the second undoped GaN layer 106b.

The light emitting structure 110 may include a first conductive AlGaN-based semiconductor layer 112, an active layer 114, and a second conductive AlGaN-based semiconductor layer 116.

The first conductive AlGaN-based semiconductor layer 112 may be formed of a compound semiconductor such as a Group 3-Group-5, Group-6, or the like, and may be doped with a first conductive-type dopant. For example, the first conductive AlGaN-based 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 conductive AlGaN-based semiconductor layer 112 is an n-type semiconductor layer, the n-type dopant may include Si, Ge, Sn, Se, and Te.

The active layer 114 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.

The active layer 114 is formed by injecting electrons (or holes) injected through the first conductive AlGaN-based semiconductor layer 112 and holes (or electrons) injected through the second conductive AlGaN-based semiconductor layer 116 And emits light according to a band gap difference of an energy band according to the material of the active layer 114. [

The active layer 114 may be made of a compound semiconductor. The active layer 114 may be formed of at least one of Group II-IV and Group III-V compound semiconductors.

The active layer 114 may include a quantum well and a quantum wall. When the active layer 114 is implemented as a multiple quantum well structure, quantum wells and quantum wells can be alternately arranged. The quantum well and the quantum well may be arranged in a semiconductor material having a composition formula of In _x Al _y Ga _1-xy (0? _X? 1, 0? _Y? 1, 0? _X + y? 1) But not limited to, any one or more pairs of GaN, AlGaN / AlGaN, InGaN / GaN, InGaN / InGaN, InAlGaN / GaN, GaAs / AlGaAs, InGaAs / AlGaAs, GaP / AlGaP and InGaP AlGaP.

The second conductive AlGaN-based semiconductor layer 116 may be formed of a compound semiconductor such as a Group III-V-V, a Group-VI-VI, or the like, and may be doped with a second conductive dopant. For example, the second conductive AlGaN-based 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 conductive AlGaN-based semiconductor layer 116 is a p-type semiconductor layer, the second conductive dopant may include Mg, Zn, Ca, Sr, and Ba as p-type dopants.

Although the first conductive AlGaN-based semiconductor layer 112 is an n-type semiconductor layer and the second conductive AlGaN-based semiconductor layer 116 is a p-type semiconductor layer, the first conductive AlGaN- 112 may be formed as a p-type semiconductor layer, and the second conductive AlGaN-based semiconductor layer 116 may be formed as an n-type semiconductor layer, but the present invention is not limited thereto. A semiconductor layer, for example, an n-type semiconductor layer (not shown) having a polarity opposite to the second conductivity type may be formed on the second conductive AlGaN-based semiconductor layer 116. Accordingly, the light emitting structure 110 may have 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.

Although the light emitting structure 110 of the embodiment is described as the first conductive AlGaN-based semiconductor layer 112 and the second conductive-type AlGaN-based semiconductor layer 116, the first conductive-type GaN- Type GaN-based semiconductor layer, but the present invention is not limited thereto.

The ultraviolet light emitting device 100 of the embodiment may include the light transmitting electrode layer 120 and the first and second electrodes 151 and 153.

The transmissive electrode layer 120 may be disposed on the second conductive AlGaN-based semiconductor layer 116. The transmissive electrode layer 120 may include an ohmic layer (not shown).

The first electrode 151 may be located on the first conductive AlGaN-based semiconductor layer 112.

The second electrode 153 may be located on the second conductive AlGaN-based semiconductor layer 116.

A light extracting pattern such as a roughness may be formed on the second conductive AlGaN-based semiconductor layer 116 and the transparent electrode layer 120, but is not limited thereto.

The ultraviolet light emitting device 100 of one embodiment is in contact with the nitride layer 107 and is formed by the un-doped AlGaN semiconductor layer 108 formed on the first undoped GaN layer 106a The crystallinity of the second undoped GaN layer 106b positioned below can be improved and the defect can be improved.

Referring to FIG. 2, the ultraviolet light emitting device 100 of one embodiment includes a first region 108a of the undoped AlGaN-based semiconductor layer 108 located on the upper surface of the first undoped GaN layer 106a, And a second region 108b of the undoped AlGaN-based semiconductor layer 108 located at the V-pit (V) of the 1-undoped GaN layer 106a. The growth rate of the undoped AlGaN-based semiconductor layer 108 may be slower than that of the first region 108a and the second region 108b. Accordingly, the Al concentration of the undoped AlGaN-based semiconductor layer 108 can be relatively larger in the first region 108a than in the second region 108b. That is, since the Al concentration is larger in the first region 108a than in the second region 108b, the binding energy of AlGaN in the first region 108a becomes larger than that in the second region 108b, Defects propagating at the lower end of the first undoped GaN layer 106 b may be bent into the second region 108 b rather than the first region 108 a and propagated to the second undoped GaN layer 106 b may be reduced.

The ultraviolet light emitting device 100 according to one embodiment is not limited to a horizontal type, and may be applied to a vertical ultraviolet light emitting device.

3 to 7 are cross-sectional views illustrating a method of manufacturing an ultraviolet light-emitting device according to an embodiment.

Referring to FIG. 3, the first undoped GaN layer 106a 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 use at least one of sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, and Ga ₂ O ₃ . The concavo-convex structure may be formed on the substrate 105, but the present invention is not limited thereto.

The first undoped GaN layer 106a may be at least one or more. That is, the first undoped GaN layer 106a may be a plurality of layers of two or more. The first undoped GaN layer 106a may include a plurality of V pits V by controlling the growth temperature or the growth pressure. For example, the first undoped GaN layer 106a can lower the mobility of Ga by adjusting the growth temperature or the growth pressure, thereby forming the first undoped GaN layer 106a including roughness . For example, the first undoped GaN layer 106a may be formed such that at least a portion thereof has a side surface and a top surface, and the side surfaces may include a plurality of V pits V. For example, the roughness may be formed regularly or irregularly, but is not limited thereto.

Referring to FIG. 4, a nitride layer 107 may be formed on the first undoped GaN layer 106a. The nitride layer 107 may be located within the V-pits V. The nitride layer 107 may be formed at the lower end of the V-pit V. The nitride layer 107 may include SiNx (x> 0), but is not limited thereto. The nitride layer 107 may be disposed within the V pits V of the first undoped GaN layer 106a to block defects occurring at the bottom of the V pits V. [ For example, the nitride layer 107 is formed of an amorphous material and is formed at the lower end of the V-pit V of the first undoped GaN layer 106a so that defects occurring at the lower end of the V- 106b and can bend the path through which defects propagate. The nitride layer 107 may be located on the upper surface of the first undoped GaN layer 106a in addition to the bottom of the V-pit V, but is not limited thereto.

Referring to FIG. 5, the undoped AlGaN-based semiconductor layer 108 may be located on the first undoped GaN layer 106a and the nitride layer 107. [ The undoped AlGaN-based semiconductor layer 108 may be in direct contact with the nitride layer 107. The undoped AlGaN-based semiconductor layer 108 can be grown on the upper surface of the first undoped GaN layer 106a and on the side of the V-pits V. The undoped AlGaN-based semiconductor layer 108 has a first region 108a located on the upper surface of the first undoped GaN layer 106a and a second region 108b located on the upper surface of the first undoped GaN layer 106a, And a second region 108b positioned on top of the second region 108b.

The growth rate of the undoped AlGaN-based semiconductor layer 108 may be slower than that of the first region 108a and the second region 108b. As a result, the Al concentration of the undoped AlGaN-based semiconductor layer 108 can be relatively larger in the first region 108a than in the second region 108b. That is, since the Al concentration is larger in the first region 108a than in the second region 108b, the binding energy of AlGaN in the first region 108a becomes larger than that in the second region 108b, The defect propagating to the second undoped GaN layer 106b can be reduced because the defect propagating at the lower end of the second undoped GaN layer 106b is bent into the second region 108b rather than the first region 108a.

The undoped AlGaN-based semiconductor layer 108 may be sputtered on the upper surface of the nitride layer 107 on the V-pit V side of the first undoped GaN layer 106a. Thus, the undoped AlGaN-based semiconductor layer 108 may cover the nitride layer 107. [

The undoped AlGaN-based semiconductor layer 108 may include a semiconductor material having a composition formula of Al _x Ga _1-x N (0.4 _{? X} ? 0.8). If the Al composition x of the undoped AlGaN-based semiconductor layer 108 is less than 0.4, the defect blocking effect of the first undoped AlGaN-based semiconductor layer 108 may be deteriorated. If the Al composition x of the undoped AlGaN-based semiconductor layer 108 is greater than 0.8, the defect bending effect of the first undoped AlGaN-based semiconductor layer 108 may be deteriorated.

The thickness of the undoped AlGaN-based semiconductor layer 108 may be 50 nm or more. For example, the thickness of the undoped AlGaN-based semiconductor layer 108 may be 5 nm to 15 nm. If the thickness of the undoped AlGaN-based semiconductor layer 108 is less than 5 nm, the defect blocking effect of the first undoped AlGaN-based semiconductor layer 108 may be deteriorated, and the second undoped AlGaN- 108 may be deteriorated. When the thickness of the undoped AlGaN-based semiconductor layer 108 is more than 15 nm, crystallinity may be deteriorated due to a high lattice constant due to a high composition.

Referring to FIG. 6, a second undoped GaN layer 106b may be grown on the undoped AlGaN-based semiconductor layer 108. The second undoped GaN layer 106b may be formed on the upper surface and the side surface of the un-doped AlGaN-based semiconductor layer 108. For example, the thickness of the second undoped GaN layer 106b may be 800 nm or more. The thickness of the second undoped GaN layer 106b may be 800 nm to 1500 nm. If the thickness of the second undoped GaN layer 106b is less than 800 nm, the defect bending effect may be deteriorated.

Referring to FIG. 7, a light emitting structure 110 may be formed on the second undoped GaN layer 106b. The light emitting structure 110 may include a first conductive AlGaN-based semiconductor layer 112, an active layer 114, and a second conductive AlGaN-based semiconductor layer 116.

The first conductive AlGaN-based semiconductor layer 112 may be formed of a compound semiconductor such as a Group 3-Group-5, Group-6, or the like, and may be doped with a first conductive-type dopant. For example, the second conductive AlGaN-based 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 conductive AlGaN-based semiconductor layer 112 is an n-type semiconductor layer, the n-type dopant may include Si, Ge, Sn, Se, and Te.

The active layer 114 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.

The active layer 114 is formed by injecting electrons (or holes) injected through the first conductive AlGaN-based semiconductor layer 112 and holes (or electrons) injected through the second conductive AlGaN-based semiconductor layer 116 And emits light according to a band gap difference of an energy band according to the material of the active layer 114. [

The active layer 114 may be made of a compound semiconductor. The active layer 114 may be formed of at least one of Group II-IV and Group III-V compound semiconductors.

The active layer 114 may include a quantum well and a quantum wall. When the active layer 114 is implemented as a multiple quantum well structure, quantum wells and quantum wells can be alternately arranged. The quantum well and the quantum well may be arranged in a semiconductor material having a composition formula of In _x Al _y Ga _1-xy (0? _X? 1, 0? _Y? 1, 0? _X + y? 1) But not limited to, any one or more pairs of GaN, AlGaN / AlGaN, InGaN / GaN, InGaN / InGaN, InAlGaN / GaN, GaAs / AlGaAs, InGaAs / AlGaAs, GaP / AlGaP and InGaP AlGaP.

The second conductive AlGaN-based semiconductor layer 116 may be formed of a compound semiconductor such as a Group III-V-V, a Group-VI-VI, or the like, and may be doped with a second conductive dopant. For example, the second conductive AlGaN-based 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 conductive AlGaN-based semiconductor layer 116 is a p-type semiconductor layer, the second conductive dopant may include Mg, Zn, Ca, Sr, and Ba as p-type dopants.

The first conductive AlGaN-based semiconductor layer 112 may be formed as a p-type semiconductor layer, and the second conductive AlGaN-based semiconductor layer 116 may be formed as an n-type semiconductor layer.

The ultraviolet light emitting device of the embodiment may include a light transmitting electrode layer 120, first and second electrodes 151 and 154 formed on the light emitting structure 110.

The transmissive electrode layer 120 may be formed on the second conductive AlGaN-based semiconductor layer 116. The light transmitting electrode layer 120 may include an ohmic layer (not shown), and may be formed by laminating a single metal, a metal alloy, a metal oxide, or the like so as to efficiently inject holes.

For example, the light transmitting electrode layer 120 may be formed of a superior material in electrical contact with a semiconductor. For example, the transmissive electrode layer 120 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (ZnO), indium gallium tin oxide (AZO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IZON nitride, AGZO Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Ni, IrOx / Au, and Ni / IrOx / , Au, and Hf, but is not limited thereto.

The light extracting pattern may be formed on the second conductive AlGaN-based semiconductor layer 116 and the transparent electrode layer 120, but is not limited thereto.

The first electrode 151 may be formed on the first conductive AlGaN-based semiconductor layer 112 exposed from the active layer 114 and the second conductive AlGaN-based semiconductor layer 116, 153 may be formed on the transparent electrode layer 120.

The first electrode 151 or the second electrode 153 may be formed of one selected from the group consisting of Ti, Cr, Ni, Al, Pt, Au, Molybdenum (Mo), but it is not limited thereto.

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

As shown in FIG. 8, the ultraviolet light-emitting device according to another embodiment may adopt the technical features of the ultraviolet light-emitting device according to the embodiment of FIG.

The ultraviolet light emitting device according to another embodiment includes a first undoped GaN layer 106a, a first nitride layer 107a, a first undoped AlGaN-based semiconductor layer 108, a second undoped GaN layer 106b, 2 nitride layer 107b, a second undoped AlGaN-based semiconductor layer 109, and a third undoped GaN layer 106c.

The first undoped GaN layer 106a, the first nitride layer 107a, the first undoped AlGaN-based semiconductor layer 108, and the second undoped GaN layer 106b, which include the V-pits V1, The detailed description will be omitted with reference to the ultraviolet light emitting device according to the embodiment. However, the second undoped GaN layer 106b may include a V-pit V2.

The second nitride layer 107b may be located within the V-pits V of the second undoped GaN layer 106b. The second nitride layer 107b may be formed at the lower end of the V-pit V2 of the second undoped GaN layer 106b. The second nitride layer 107b may include SiNx (x> 0), but is not limited thereto. The second nitride layer 107b may be formed at the V pit V2 of the second undoped GaN layer 106b to block defects occurring at the lower end of the V pit V2. For example, the second nitride layer 107b is formed of an amorphous material and is formed at the lower end of the V-pit V2 of the second undoped GaN layer 106b, so that defects occurring at the lower end of the V- Propagation to the undoped GaN layer 106c can be reduced, and the path through which the defect propagates can be bent. The second nitride layer 107b may be located on the upper surface of the second undoped GaN layer 106b in addition to the bottom of the V-pit V2.

The second undoped AlGaN-based semiconductor layer 109 may be located on the second nitride layer 107b. The second undoped AlGaN-based semiconductor layer 109 may be in direct contact with the second nitride layer 107b. The second undoped AlGaN-based semiconductor layer 109 may be grown on the upper surface and the side surface (V-pit side) of the second undoped GaN layer 106b. The second undoped AlGaN-based semiconductor layer 109 has a third region 109a formed on the upper surface of the second undoped GaN layer 106b and a second region 109b formed on the upper surface of the second undoped GaN layer 106b. V2) of the first region 109b. The growth rate of the second undoped AlGaN-based semiconductor layer 109 may be slower than that of the fourth region 109b in the third region 109a. Accordingly, the Al concentration of the second undoped AlGaN-based semiconductor layer 109 can be relatively larger in the third region 109a than in the fourth region 109b. That is, since the Al concentration is larger in the third region 109a than in the fourth region 109b, the binding energy of AlGaN in the third region 109a becomes larger than that of the fourth region 109b, The defect propagating to the third undoped GaN layer 106c can be reduced because the defect propagating at the lower end of the third undoped GaN layer 106c is bent to the fourth region 109b rather than the third region 109a.

The second undoped AlGaN-based semiconductor layer 109 may include a semiconductor material having a composition formula of Al _y Ga _1-y N (0.4 _{? Y} ? 0.8). If the Al composition (y) of the second undoped AlGaN-based semiconductor layer 109 is less than 0.4, the defect blocking effect of the third region 109a may be deteriorated. When the Al composition (y) of the second undoped AlGaN-based semiconductor layer 109 is more than 0.8, the defect bending effect of the fourth region 109b may be deteriorated.

The thickness of the second undoped AlGaN-based semiconductor layer 109 may be 50 nm or more. For example, the thickness of the second undoped AlGaN-based semiconductor layer 109 may be 5 nm to 15 nm. If the thickness of the second undoped AlGaN-based semiconductor layer 109 is less than 5 nm, the defect blocking effect of the third region 109a may be deteriorated and the defect bending effect of the fourth region 109b may deteriorate . When the thickness of the second undoped AlGaN-based semiconductor layer 109 is more than 15 nm, crystallinity may be deteriorated due to a high lattice constant difference due to a high composition.

The third undoped GaN layer 106c may be located on the second undoped AlGaN-based semiconductor layer 109. The third undoped GaN layer 106c may have a thickness of 800 nm or more. For example, the thickness of the third undoped GaN layer 106c may be 800 nm to 1500 nm. If the thickness of the third undoped GaN layer 106c is less than 800 nm, the defect bending effect may be deteriorated.

In the ultraviolet light emitting device according to another embodiment, the second undoped AlGaN-based semiconductor layer 109 is positioned on the second undoped GaN layer 106b and the second nitride layer 107b to further improve the crystallinity , Defects that have passed through the first undoped AlGaN-based semiconductor layer 108 can be improved.

The ultraviolet light emitting device according to another embodiment is characterized in that the first undoped AlGaN-based semiconductor layer 108 is located on the first nitride layer 107a and the second undoped AlGaN-based semiconductor layer 109 is located on the second nitride layer 107b The present invention is not limited to this, and the first undoped AlGaN-based semiconductor layer 108 and the second undoped GaN layer 106b may be formed on the first nitride layer 107a at least two And the second undoped AlGaN-based semiconductor layer 109 and the third undoped GaN layer 106c may be alternated with at least two pairs on the second nitride layer 107b.

Comparative Example Experimental Example 1
(x = 0.4, T: 5 nm) Experimental Example 2
(x = 0.4, T: 10 nm) Experimental Example 3
(x = 0.6, T: 10 nm) nAlGaN (002)
(center / edge) 158/169 154/159 145/148 120/129 nAlGaN (102)
(center / edge) 197/207 181/195 175/192 162/160

Table 1 shows a comparative example in which an undoped AlGaN-based semiconductor layer is not formed on the undoped GaN layer and a comparative example in which the undoped GaN layer is formed on the undoped GaN layer in the other embodiment of FIG. 8 including the first and second undoped AlGaN- Are data obtained by comparing the crystallinity and TDD (Threading Dislocation Density) of Experimental Examples 1 to 3 to which the ultraviolet light emitting device according to the present invention is applied. Here, the crystallinity can compare the center region and the edge region of the wafer. The XRD measurement is data obtained by measuring the 002 and 102 planes of the first conductive AlGaN-based semiconductor layer.

Experimental Example 1 includes first and second undoped AlGaN-based semiconductor layers having an Al composition (x) of 0.4 and a thickness of 5 nm, Experimental Example 2 has an Al composition (x) of 0.4 and a thickness of 10 nm And Example 3 contains first and second undoped AlGaN-based semiconductor layers having an Al composition (x) of 0.6 and a thickness of 10 nm.

It can be seen that Examples 1 to 3 have improved crystallinity because XRD FWHM is lower than that of Comparative Examples.

9A and 9B are photographs of TD density comparison of Comparative Examples and Experimental Examples.

In the ultraviolet light emitting device, the indium (In) composition of the light emitting structure is lower than that of the blue light emitting device, so that the In restraining effect is hardly observed. The ultraviolet light-emitting device causes a decrease in luminous intensity due to non-radiative recombination around the TD (Threading dislocation) of the lower layer of the light emitting structure. Therefore, the ultraviolet light-emitting device can significantly affect the chip luminous efficiency and the TD control and crystallinity of the light-emitting structure and the lower layer of the light-emitting structure.

FIG. 9A shows a TD of a comparative example in which a first conductivity type AlGaN-based semiconductor layer is formed without an undoped AlGaN semiconductor layer on the undoped GaN layer, and FIG. 9B shows a first- And the first conductive AlGaN-based semiconductor layer is formed after the AlGaN-based semiconductor layer is formed. In the embodiment, defects are bent by the undoped AlGaN-based semiconductor layer, so that TD can be remarkably reduced. Therefore, the ultraviolet light emitting device of the embodiment has a low indium (In) composition and can reduce non-radiative recombination in TD.

Therefore, the embodiment can improve the crystallinity and improve the Chip luminous intensity as compared with the comparative example by reducing the TD to form the undoped AlGaN-based semiconductor layer on the nitride layer.

The ultraviolet light emitting devices according to the embodiments may have a structure in which a plurality of the ultraviolet light emitting devices are arrayed, and may be included in the light emitting device package. The ultraviolet light emitting device according to the embodiments can be used in various fields such as curing, sterilization, special illumination, etc. according to wavelengths.

The ultraviolet light emitting device according to the embodiment can be applied to a backlight unit, a lighting device, a display device, a vehicle display device, a smart unit, but is not limited thereto.

10 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 205, a first lead electrode 213 and a second lead electrode 214 provided on the package body 205, And a molding member 230 surrounding the ultraviolet light emitting device 100 is formed on the first lead electrode 213 and the second lead electrode 214. The ultraviolet light emitting device 100 is electrically connected to the first lead electrode 213 and the second lead electrode 214, .

The first lead electrode 213 and the second lead electrode 214 are electrically isolated from each other and serve to supply power to the ultraviolet light emitting device 100. The first lead electrode 213 and the second lead electrode 214 may include a function of increasing light efficiency by reflecting light emitted from the ultraviolet light emitting device 100, 100 may be discharged 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 wire, flip chip, and die bonding methods.

The ultraviolet light-emitting device 100 may be an ultraviolet light-emitting device according to an embodiment of the present invention, but it may be an ultraviolet light-emitting device according to another embodiment.

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

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

The features, structures, effects and the like described in the embodiments are included in at least one embodiment and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects and the like illustrated in the embodiments can be combined and modified by other persons skilled in the art to which the embodiments belong. Accordingly, the contents of such combinations and modifications should be construed as being included in the scope of the embodiments.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. It can be seen that the modification and application of branches are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

105: substrate 106a: first undoped GaN layer
107: nitride layer 108: first undoped AlGaN-based semiconductor layer
106b: second undoped GaN layer 109: second undoped AlGaN-based semiconductor layer
106c: a third undoped GaN layer

Claims (8)

Board;
A first undoped GaN layer comprising a V-pit having a top surface and a side surface on at least a portion of the substrate;
A first nitride layer disposed on the V-pit of the first undoped GaN layer;
A first undoped AlGaN-based semiconductor layer disposed on the first undoped GaN layer and the first nitride layer; And
And a second undoped GaN layer located on the first undoped AlGaN-based semiconductor layer,
Wherein the first undoped AlGaN-based semiconductor layer comprises a first region located on a top surface of the first undoped GaN layer and a second region located on a V-pit of the first undoped GaN layer,
Wherein an Al concentration of the first region is larger than an Al concentration of the second region. The method according to claim 1,
Wherein the first undoped AlGaN-based semiconductor layer has an Al composition of Al _x Ga _1-x N (0.4 _{? X} ? 0.8). The method according to claim 1,
The thickness of the first undoped AlGaN-based semiconductor layer is 5 nm to 15 nm. The method according to claim 1,
And the thickness of the second undoped GaN layer is 800 nm to 1500 nm. The method according to claim 1,
Wherein at least two pairs of the first undoped AlGaN-based semiconductor layer and the second undoped GaN layer are disposed on the first waved layer. The method according to claim 1,
The second undoped GaN layer comprising a flat top surface and a V-pit, the second nitride layer disposed on the V-pit of the second undoped GaN layer;
A second undoped AlGaN-based semiconductor layer disposed on the second undoped GaN layer and the second nitride layer; And
And a third undoped GaN layer located on the second undoped AlGaN-based semiconductor layer,
The second undoped AlGaN-based semiconductor layer comprises a third region located on the upper surface of the second undoped GaN layer and a fourth region located on the V-pit of the second undoped GaN layer,
And the Al concentration in the third region is larger than the Al concentration in the fourth region. A light emitting device package comprising an ultraviolet light emitting element according to any one of claims 1 to 14. A lighting device comprising an ultraviolet light-emitting element according to any one of claims 1 to 14.

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