KR20170071906A - Uv light emitting device and light emitting device package - Google Patents

Abstract

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.
The ultraviolet light emitting device according to the embodiment includes a light emitting structure including an AlGaN-based first conductive type first semiconductor layer, an active layer, and a second conductive type semiconductor layer, a first electrode on the second conductive type semiconductor layer, And a current spreading layer in contact with the first electrode on the semiconductor layer and including the first conductive type second semiconductor layer to the first conductive type fourth semiconductor layer. The embodiment is characterized in that the current spreading layer is in ohmic contact with the second conductivity type semiconductor layer and the first electrode to improve the light absorption of the ultraviolet wavelength and to reduce current spreading by the doped first dopant and Al composition Can be improved.

Description

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

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.

The light emitting diode may 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.

Typical ultraviolet light emitting devices include a transparent contact layer for ohmic contact between the p-type semiconductor layer and the electrode. ITO is mainly used as a general transparent contact layer.

However, a general ultraviolet light emitting device has a problem that ITO, which has excellent ohmic contact characteristics, absorbs a part of light having an ultraviolet wavelength, resulting in a decrease in brightness.

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 capable of improving current spreading and electrical characteristics.

The ultraviolet light emitting device according to the embodiment includes a light emitting structure 110 including a first conductive type first semiconductor layer, an active layer, and a second conductive type semiconductor layer; A first electrode 170 below the light emitting structure; And a current spreading layer (130) in contact with the light emitting structure and the first electrode, wherein the current spreading layer includes a first conductive type second semiconductor layer to a first conductive type fourth semiconductor layer (131, 133, 135) And the first conductive type third semiconductor layer 133 may have a lower doping concentration than the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 . The embodiment is characterized in that the current spreading layer is in ohmic contact with the second conductivity type semiconductor layer and the first electrode to improve the light absorption of the ultraviolet wavelength and to improve the current spreading by the doped first dopant and the Al composition Can be improved.

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

In the ultraviolet light emitting device of the embodiment, a current spreading layer is disposed between the AlGaN-based light emitting structure and the electrode, and the current spreading layer can reduce the light absorption of ultraviolet wavelength to improve the light intensity. The current spreading layer is formed of an AlGaN-based semiconductor layer including a first conductive dopant between the second conductive semiconductor layer and the electrode, thereby improving ohmic contact and current spreading.

1 is a plan view showing an ultraviolet light emitting device according to an embodiment.
2 is a cross-sectional view of an ultraviolet light-emitting device taken along line I-I 'of FIG.
3 is a cross-sectional view showing the current spreading layer in the embodiment.
4 to 8 are cross-sectional views illustrating a method of manufacturing an ultraviolet light-emitting device according to an embodiment.
9 is a cross-sectional view illustrating an ultraviolet light-emitting device according to another embodiment.
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 plan view showing an ultraviolet light-emitting device according to an embodiment, FIG. 2 is a sectional view of an ultraviolet light-emitting device cut along a line I-I 'of FIG. 1, to be.

1 to 3, the ultraviolet light-emitting device 100 according to the embodiment may include a light-emitting structure 110.

The light emitting structure 110 may include a first conductive type first semiconductor layer 112, an active layer 114, and a second conductive type semiconductor layer 116. In the embodiment, the ultraviolet light emitting device 100 that emits light having an ultraviolet wavelength of 400 nm or less will be described as an example. For example, the light emitting structure 110 may be an AlGaN-based semiconductor.

The first conductive type first semiconductor layer 112 may be formed of a semiconductor compound, for example, a compound semiconductor such as Group II-IV or Group III-V, and may be doped with a first conductive type dopant. For example, the first conductive type first 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 type first semiconductor layer 112 is an n-type semiconductor layer, it may include Si, Ge, Sn, Se, and Te as an n-type dopant, but is not limited thereto. The first conductive type first semiconductor layer 112 may include a light extracting pattern 113 for improving light extraction efficiency. The light extracting pattern 113 may be formed by a method such as PEC, but is not limited thereto. The light extracting patterns 113 may be formed to have regular shapes and arrangements, and may have irregular shapes and arrangements. For example, the cross section of the light extracting pattern 113 may be polygonal, circular or elliptical, but is not limited thereto. The light extracting pattern 113 refracts light, which is totally reflected from the upper surface of the first conductive type semiconductor layer 112 and reabsorbed, out of the light generated from the active layer 114 to improve light extraction efficiency .

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.

Electrons (or holes) injected through the first conductive type second semiconductor layer 112 and holes (or electrons) injected through the second conductive type semiconductor layer 116 meet with each other in the active layer 114 And a band gap of an energy band according to a material of the active layer 114. The light emitting layer is a layer which emits light according to a band gap of an energy band according to a 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 wall may be arranged in a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) But not limited to, any one or more pairs of AlGaN / GaN, AlGaN / AlGaN, InGaN / GaN, InGaN / InGaN, InAlGaN / GaN, GaAs / AlGaAs, InGaAs / AlGaAs, GaP / AlGaP and InGaP AlGaP.

The second conductive semiconductor layer 116 may be formed of a semiconductor compound, for example, a compound semiconductor such as Group II-IV and Group III-V, and may be doped with a second conductive dopant. For example, the second conductive 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 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 type first semiconductor layer 112 is an n-type semiconductor layer and the second conductive type semiconductor layer 116 is a p-type semiconductor layer, the first conductive type first semiconductor layer 112, And the second conductivity type semiconductor layer 116 may be formed of an n-type semiconductor layer, but the present invention is not limited thereto. An n-type semiconductor layer (not shown) having a polarity opposite to that of the second conductivity type may be formed on the second conductivity type semiconductor layer 116, for example. 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.

The ultraviolet light emitting device 100 according to the embodiment may include a current spreading layer 130, first and second electrodes 170 and 160.

The current spreading layer 130 may be disposed on the first and second electrodes 170 and 160. The current spreading layer 130 may be disposed below the light emitting structure 110. The current spreading layer 130 may be disposed between the light emitting structure 110 and the first electrode 170. Here, the first electrode 170 may be disposed on the second electrode 160. The current spreading layer 130 may be in ohmic contact with the light emitting structure 110 and the first electrode 170. The current spreading layer 130 may include a first conductive type second semiconductor layer 131, a first conductive type third semiconductor layer 133, and a first conductive type fourth semiconductor layer 135. The current spreading layer 130 is composed of an AlGaN-based semiconductor layer, and the decrease in luminous intensity due to light absorption can be improved. For example, the current spreading layer 130 can improve light absorption of ultraviolet wavelengths. The current spreading layer 130 is formed of an AlGaN-based semiconductor layer including a first conductive dopant between the second conductive type semiconductor layer 116 and the first electrode 170 to improve ohmic contact and current spreading can do.

The first conductive type second semiconductor layer 131 may be in direct contact with the second conductive type semiconductor layer 116. The first conductive type second semiconductor layer 131 may be disposed between the second conductive type semiconductor layer 116 and the first conductive type third semiconductor layer 133. The first conductive type fourth semiconductor layer 135 may be in direct contact with the first electrode 170. The first conductive type fourth semiconductor layer 135 may be disposed between the first electrode 170 and the first conductive type third semiconductor layer 133. The first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may be formed of a semiconductor compound such as a compound semiconductor such as a Group II-IV and a Group III- A first conductivity type dopant may be doped. For example, the first conductive type dopant may include Si, Ge, Sn, Se, and Te as an n-type dopant, but the present invention is not limited thereto. The first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may include an n-type doping concentration of 1.0 x 10 ¹⁹ atoms / cm 3 or more. For example, the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 reduce the depletion region of the PN junction by an n-type doping concentration of 1.0 x 10 ¹⁹ atoms / cm 3 or more, Can be implemented. The first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may include an n type doping concentration of 1.0 x 10 ¹⁹ atoms / cm 3 to 5.0 x 10 ²⁰ atoms / cm 3 . When the n-type doping concentration of the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 is less than 1.0 x 10 ¹⁹ atoms / cm 3, the tunneling effect by the n-type dopant Can be lowered. That is, the ohmic contact between the first conductive type second semiconductor layer 131 and the second conductive type semiconductor layer 116 may not be formed well. The ohmic contact between the first conductive type fourth semiconductor layer 135 and the first electrode 170 may not be formed well. If the n-type doping concentration of the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 exceeds 5.0 x 10 ²⁰ atoms / cm 3, the crystallinity may be lowered.

The first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may include a semiconductor material having a composition formula of Al _c Ga _1-c N (0 < _c ? 0.04) . The Al composition ratio of the first conductive type third semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may be more than 0% and 4% or less, more specifically, 2% to 3% Not limited. The first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 can improve light absorption by a composition of Al exceeding zero. When the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 have a composition c of 0 and do not contain Al, that is, they are formed of GaN, they absorb light So that the light intensity may be lowered. When the composition c of Al is more than 0.04, the amount of Al increases so that the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 are electrically connected to the second conductive type semiconductor layer Ohmic contact with the first electrode 116 and the first electrode 170 may not be formed well.

The first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may have a thickness of 1 nm or more. For example, the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may have a thickness of 1 nm to 3 nm. When the thickness of the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 is less than 1 nm, the second conductive type semiconductor layer 116 and the first electrode 170, Ohmic contact may not be formed well. If the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 have a thickness of more than 3 nm, the light absorption may decrease due to light absorption.

Although the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 include the same doping concentration, Al composition and thickness, the embodiment is not limited thereto . For example, the doping concentration, Al composition, and thickness of the first and second semiconductor layers 131 and 135 may be varied within the range described above.

The first conductive type third semiconductor layer 133 of the embodiment may be disposed between the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135. The first conductive type third semiconductor layer 133 may be formed of a semiconductor compound, for example, a compound semiconductor such as Group II-IV or Group III-V, and may be doped with a first conductive type dopant. For example, the first conductive type dopant may include Si, Ge, Sn, Se, and Te as an n-type dopant, but the present invention is not limited thereto. The first conductive type third semiconductor layer 133 may include a lower doping concentration than the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135. The first conductive type third semiconductor layer 133 is disposed between the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 to form n-type doping Concentration may be required. Here, the crystallinity of the first conductive type third semiconductor layer 133 may be lowered as the n-type doping concentration is higher. More specifically, the first conductive type third semiconductor layer 133 may have a lower doping concentration than the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 disposed for ohmic contact, To improve crystallinity. The first conductive type third semiconductor layer 133 may include an n-type doping concentration of 1.0 x 10 ¹⁹ atoms / cm 3 to 5.0 x 10 ¹⁹ atoms / cm 3. If the n-type doping concentration of the first conductive type third semiconductor layer 133 is less than 1.0 x 10 ¹⁹ atoms / cm 3, the current spreading effect may be lowered. When the n-type doping concentration of the first conductive type third semiconductor layer is more than 5.0 x 10 ¹⁹ atoms / cm 3, the operating voltage may be increased and the crystallinity may be lowered due to an increase in contact resistance.

The first conductive type third semiconductor layer 133 may include a semiconductor material having a composition formula of Al _d Ga _1-d N (0.02 _{? D} ? 0.07). The composition ratio of Al of the first conductive type third semiconductor layer 133 is 2% to 7%, and may include a barrier function and a current spreading function. More specifically, the Al composition ratio of the first conductive type third semiconductor layer 133 may be 5% to 7%, but is not limited thereto. If the composition d of Al is less than 0.02, the light absorption may be lowered by light absorption. When the composition d of Al is more than 0.07, the crystallinity may be lowered. The conductive AlGaN-based third semiconductor layer 133 of the embodiment includes a constant composition of Al, but is not limited thereto. For example, the Al composition d of the first conductive type third semiconductor layer 133 can be adjusted within the composition range of Al and can be made larger or smaller as the conductive type fourth semiconductor layer 135, for example.

The thickness of the first conductive type third semiconductor layer 133 may be 10 nm or more. For example, the thickness of the first conductive type third semiconductor layer 133 may be 10 nm to 20 nm. If the thickness of the first conductive type third semiconductor layer 133 is less than 10 nm, the current spreading effect may be lowered. If the thickness of the first conductive type third semiconductor layer 133 is more than 20 nm, the operating voltage may be increased due to an increase in contact resistance, and the luminous efficiency may be lowered.

The current spreading layer 130 is disposed between the light emitting structure 110 and the second electrode 160 to form an ohmic contact between the light emitting structure 110 and the second electrode 160. [ And the current spreading effect can be improved.

The first electrode 170 may include a reflective layer 173, a capping layer 175, and a pad 177. The reflective layer 173 and the capping layer 175 may be disposed under the current spreading layer 130. The reflective layer 173 and the capping layer 175 may be disposed between the current spreading layer 130 and the second electrode 160. The first electrode 170 may be electrically connected to the second conductive semiconductor layer 116. The first electrode 170 may be electrically insulated from the second electrode 160.

The reflective layer 173 may be disposed between the current spreading layer 130 and the capping layer 175. The reflective layer 173 may be electrically connected to the current spreading layer 130 and the capping layer 175. The reflective layer 173 may include a function of reflecting light incident from the light emitting structure 110. The reflective layer 173 may improve light extraction efficiency by reflecting light from the light emitting structure 110 to the outside. The reflective layer 173 may be a metal. For example, the reflective layer 173 may be a metal or an alloy including at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Cu, .

The capping layer 175 may be disposed under the reflective layer 173. The capping layer 175 may be in contact with the reflective layer 173. For example, the capping layer 175 may be in direct contact with the bottom surface of the reflective layer 173, but is not limited thereto. The capping layer 175 may be disposed below the pad 177. The capping layer 175 may be electrically connected to the pad 177. The capping layer 175 may be in contact with the pad 177. For example, the capping layer 175 may be in direct contact with the bottom of the pad 177, but is not limited thereto. The capping layer 175 may provide the driving power supplied from the pad 177 to the light emitting structure 110. The capping layer 175 may be a conductive material. For example, the capping layer 175 may include at least one of Au, Cu, Ni, Ti, Ti, W, Cr, W, Pt, V, Fe and Mo. The edge of the capping layer 175 may be disposed outside the edge of the light emitting structure 110, but is not limited thereto.

The pad 177 may be spaced apart from the light emitting structure 110. The pad 177 may be disposed outside the light emitting structure 110. The pad 177 may be disposed on the first capping layer 175 disposed outside the light emitting structure 110. The pad 177 may include at least one of Ti, Cr, Ni, Al, Pt, Au, W, Cu, Mo, Cu-W, Be, Zn and Ge. .

The second electrode 160 may be disposed below the first electrode 170. The second electrode 160 may be electrically connected to the first conductive type first semiconductor layer 112. The second electrode 160 may include a diffusion prevention layer 161, a bonding layer 163, and a support member 165. The second electrode 160 may selectively include one or two of the diffusion preventing layer 161, the bonding layer 163, and the supporting member 165. For example, the second electrode 160 may remove at least one of the diffusion prevention layer 161 and the bonding layer 163.

The diffusion preventing layer 161 may include a function of preventing the diffusion of a material contained in the bonding layer 163 with the first electrode 170. The diffusion preventing layer 161 may be electrically connected to the bonding layer 163 and the support member 165. The diffusion barrier layer 161 may include at least one of Cu, Ni, Ti, W, Cr, W, Pt, V, Fe and Mo. The diffusion barrier layer 161 is formed on the second electrode 160, the current spreading layer 130, the second conductivity type semiconductor layer 116, and the active layer 114 by the recess 141 and the insulating layer 143, And may be electrically connected to the first conductive type first semiconductor layer 112.

The bonding layer 163 may be disposed under the diffusion barrier layer 161. The bonding layer 163 may be disposed between the diffusion barrier layer 161 and the support member 165. The bonding layer 163 may include a barrier metal or a bonding metal. For example, the bonding layer 163 may include at least one of Ti, Au, Sn, Ni, Cr, Ga, In, Bi, Cu, Ag, Nb, Pd and Ta.

The support member 165 may be a metal or a carrier substrate. For example, the support member 165 may be a semiconductor substrate (e.g., Si, Ge, GaN) doped with Ti, Cr, Ni, Al, Pt, Au, W, Cu, Mo, Cu-W, , GaAs, ZnO, SiC, SiGe, or the like), and may be formed as a single layer or a multilayer.

The first conductive semiconductor structure may be disposed between the light emitting structure 110 and the second electrode 160 to improve light intensity by reducing light absorption.

In addition, in the ultraviolet light emitting device 100 of the embodiment, the first conductive semiconductor structure may be disposed between the light emitting structure 110 and the second electrode 160 to improve the current spreading effect.

4 to 8 are cross-sectional views illustrating a method of manufacturing an ultraviolet light-emitting device according to an embodiment.

3 and 4, the light emitting structure 110, the current spreading layer 130, the reflective layer 173, and the capping layer 175 may be formed on the substrate 5.

The substrate 5 may be formed of a material having excellent thermal conductivity, and may be a conductive substrate or an insulating substrate. For example, the substrate 5 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 for improving light extraction efficiency may be formed on the substrate 5, but the present invention is not limited thereto.

The light emitting structure 110 may be formed using a metal organic chemical vapor deposition (MOCVD) method, a chemical vapor deposition (CVD) method, a plasma enhanced chemical vapor deposition (PECVD) method, a molecular beam epitaxy , Molecular Beam Epitaxy, and Hydride Vapor Phase Epitaxy (HVPE), but the present invention is not limited thereto.

The light emitting structure 110 may be formed on the substrate 5. The light emitting structure 110 may include a first conductive type first semiconductor layer 112, an active layer 114, and a second conductive type semiconductor layer 116.

The first conductive type first semiconductor layer 112 may be formed of a semiconductor compound, for example, a compound semiconductor such as Group II-IV or Group III-V, and may be doped with a first conductive type dopant. For example, the first conductive type first 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 type first semiconductor layer 112 is an n-type semiconductor layer, it may include Si, Ge, Sn, Se, and Te as an n-type dopant, but is not limited thereto.

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.

Electrons (or holes) injected through the first conductive type second semiconductor layer 112 and holes (or electrons) injected through the second conductive type semiconductor layer 116 meet with each other in the active layer 114 And a band gap of an energy band according to a material of the active layer 114. The light emitting layer is a layer which emits light according to a band gap of an energy band according to a 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 wall may be arranged in a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) But not limited to, any one or more pairs of AlGaN / GaN, AlGaN / AlGaN, InGaN / GaN, InGaN / InGaN, InAlGaN / GaN, GaAs / AlGaAs, InGaAs / AlGaAs, GaP / AlGaP and InGaP AlGaP.

The second conductive semiconductor layer 116 may be formed of a semiconductor compound, for example, a compound semiconductor such as Group II-IV and Group III-V, and may be doped with a second conductive dopant. For example, the second conductive 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 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 current spreading layer 130 may be formed on the light emitting structure 110. The current spreading layer 130 may be formed using a chemical vapor deposition (CVD) method, a molecular beam epitaxy (MBE) method, a sputtering method, or a vapor phase epitaxy (HVPE) method. The current spreading layer 130 may be formed on the second conductive semiconductor layer 116 and may be in ohmic contact with the second conductive semiconductor layer 116. The current spreading layer 130 may include a first conductive type second semiconductor layer 131, a first conductive type third semiconductor layer 133, and a first conductive type fourth semiconductor layer 135. The current spreading layer 130 is composed of an AlGaN-based semiconductor layer, and the decrease in luminous intensity due to light absorption can be improved. For example, the current spreading layer 130 can improve light absorption of ultraviolet wavelengths. The current spreading layer 130 may be formed of an AlGaN-based semiconductor layer including a first conductive dopant to improve ohmic contact and current spreading.

The first conductive type second semiconductor layer 131 may be formed on the second conductive type semiconductor layer 116. The first conductive type second semiconductor layer 131 may be in direct contact with the second conductive type semiconductor layer 116. The first conductive type second semiconductor layer 131 may be disposed between the second conductive type semiconductor layer 116 and the first conductive type third semiconductor layer 133. The first conductive type fourth semiconductor layer 135 may be disposed on the first conductive type third semiconductor layer 133. The first conductive type fourth semiconductor layer 135 may be in direct contact with the reflective layer 173 to be formed later. The first conductive type fourth semiconductor layer 135 may be disposed between the reflective layer 173 and the first conductive type third semiconductor layer 133. The first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may be formed of a semiconductor compound such as a compound semiconductor such as a Group II-IV and a Group III- A first conductivity type dopant may be doped. For example, the first conductive type dopant may include Si, Ge, Sn, Se, and Te as an n-type dopant, but the present invention is not limited thereto. The first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may include an n-type doping concentration of 1.0 x 10 ¹⁹ atoms / cm 3 or more. For example, the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 reduce the depletion region of the PN junction by an n-type doping concentration of 1.0 x 10 ¹⁹ atoms / cm 3 or more, (Tunneling) can be implemented. The first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may include an n type doping concentration of 1.0 x 10 ¹⁹ atoms / cm 3 to 5.0 x 10 ²⁰ atoms / cm 3 . When the n-type doping concentration of the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 is less than 1.0 x 10 ¹⁹ atoms / cm 3, the tunneling effect by the n-type dopant Can be lowered. That is, the ohmic contact between the first conductive type second semiconductor layer 131 and the second conductive type semiconductor layer 116 may not be formed well. The ohmic contact between the first conductive type fourth semiconductor layer 135 and the reflective layer 173 may not be well formed. If the n-type doping concentration of the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 exceeds 5.0 x 10 ²⁰ atoms / cm 3, the crystallinity may be lowered.

The first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may include a semiconductor material having a composition formula of Al _c Ga _1-c N (0 < _c ? 0.04) . The Al composition ratio of the first conductive type third semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may be more than 0% and 4% or less, more specifically, 2% to 3% Not limited. The first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 can improve light absorption by a composition of Al exceeding zero. When the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 do not contain Al, that is, GaN, when the composition c of Al is 0, the light is absorbed So that the light intensity may be lowered. When the composition c of Al is more than 0.04, the amount of Al increases, so that the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 are formed in the second conductive type semiconductor layer 116 and the reflective layer 173 may not be formed well.

The first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may have a thickness of 1 nm or more. For example, the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 may have a thickness of 1 nm to 3 nm. When the thickness of the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 is less than 1 nm, the ohmic contact with the second conductive type semiconductor layer 116 and the reflective layer 173 May not be formed well. If the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 have a thickness of more than 3 nm, the light absorption may decrease due to light absorption.

Although the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 include the same doping concentration, Al composition and thickness, the embodiment is not limited thereto . For example, the doping concentration, Al composition, and thickness of the first and second semiconductor layers 131 and 135 may be varied within the range described above.

The first conductive type third semiconductor layer 133 of the embodiment may be formed between the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135. The first conductive type third semiconductor layer 133 may be formed of a semiconductor compound, for example, a compound semiconductor such as Group II-IV or Group III-V, and may be doped with a first conductive type dopant. For example, the first conductive type dopant may include Si, Ge, Sn, Se, and Te as an n-type dopant, but the present invention is not limited thereto. The first conductive type third semiconductor layer 133 may include a lower doping concentration than the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135. The first conductive type third semiconductor layer 133 is disposed between the first conductive type second semiconductor layer 131 and the first conductive type fourth semiconductor layer 135 to form n-type doping Concentration may be required. The first conductive type third semiconductor layer 133 may include an n-type doping concentration of 1.0 x 10 ¹⁹ atoms / cm 3 to 5.0 x 10 ¹⁹ atoms / cm 3. If the n-type doping concentration of the first conductive type third semiconductor layer 133 is less than 1.0 x 10 ¹⁹ atoms / cm 3, the current spreading effect may be lowered. When the n-type doping concentration of the first conductive type third semiconductor layer is greater than 5.0 x 10 ¹⁹ atoms / cm 3, the operating voltage can be increased by an increase in contact resistance.

The first conductive type third semiconductor layer 133 may include a semiconductor material having a composition formula of Al _d Ga _1-d N (0.02 _{? D} ? 0.07). The composition ratio of Al of the first conductive type third semiconductor layer 133 is 2% to 7%, and may include a barrier function and a current spreading function. More specifically, the Al composition ratio of the first conductive type third semiconductor layer 133 may be 5% to 7%, but is not limited thereto. When the composition d of Al is less than 0.02, the light absorption may be lowered by light absorption. When the composition d of Al is more than 0.07, the crystallinity may be lowered. The conductive AlGaN-based third semiconductor layer 133 of the embodiment includes a constant composition of Al, but is not limited thereto. For example, the Al composition of the first conductive type third semiconductor layer 133 may be increased or decreased toward the first conductive type fourth semiconductor layer 135 within the Al composition range.

The thickness of the first conductive type third semiconductor layer 133 may be 10 nm or more. For example, the thickness of the first conductive type third semiconductor layer 133 may be 10 nm to 20 nm. If the thickness of the first conductive type third semiconductor layer 133 is less than 10 nm, the current spreading effect may be lowered. If the thickness of the first conductive type third semiconductor layer 133 is more than 20 nm, the operating voltage may be increased due to an increase in contact resistance, and the luminous efficiency may be lowered.

The reflective layer 173 may be formed on the current spreading layer 130. The reflective layer 173 may include a function of reflecting light incident from the light emitting structure 110. The reflective layer 173 may improve light extraction efficiency by reflecting light from the light emitting structure 110 to the outside. The reflective layer 173 may be a metal. For example, the reflective layer 173 may be a metal or an alloy including at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Cu, can do.

The capping layer 175 may be formed on the reflective layer 173. The capping layer 175 may be in direct contact with the lower surface of the reflective layer 173, but is not limited thereto. The capping layer 175 may be a conductive material. For example, the capping layer 175 may include at least one of Au, Cu, Ni, Ti, Ti, W, Cr, W, Pt, V, Fe and Mo. The edge of the capping layer 175 may be disposed outside the edge of the light emitting structure 110, but the present invention is not limited thereto.

Referring to FIG. 5, a plurality of recesses 141 may be formed in the light emitting structure 110. The recess 141 may be formed through an etching process. The recess 141 may expose a part of the first conductive type first semiconductor layer 112 to the outside. The recess 141 exposes the sides of the capping layer 175, the reflective layer 173 and the current spreading layer 130 to the outside and the side surfaces of the second conductivity type semiconductor layer 116 and the active layer 114 And can be exposed to the outside. The first conductive type first semiconductor layer 112 may be exposed on the bottom surface of the recess 141.

Referring to FIG. 6, an insulating layer 143 may be formed on the capping layer 175 and the recess 141, and a second electrode 160 may be formed on the insulating layer 143.

The insulating layer 143 may isolate the reflective layer 173 and the capping layer 175 from the second electrode 160. The insulating layer 143 may isolate the second electrode 160 from the second conductive semiconductor layer 116. The insulating layer 143 may be formed on the side of the recess 141. That is, the insulating layer 143 includes a capping layer 175, a reflective layer 173, a current spreading layer 130, a second conductive semiconductor layer 116, an active layer (not shown) exposed at the side of the recess 141 114 and the first conductive type semiconductor layer 112 may be insulated. The insulating layer 143 may expose a portion of the first conductive type semiconductor layer 112 located on the bottom surface of the recess 141. The insulating layer 143 may be an oxide or a nitride. The insulating layer 143 may be at least one selected from the group consisting of SiO ₂ , Si _x O _y , Si ₃ N ₄ , Si _x N _y , SiO _x N _y , Al ₂ O ₃ , TiO ₂ , have.

The second electrode 160 may be formed on the insulating layer 143. The second electrode 160 may be formed on the first conductive semiconductor layer 112 exposed on the bottom surface of the recess 141. The second electrode 160 may be electrically connected to the first conductive type first semiconductor layer 112. The second electrode 160 may include a diffusion prevention layer 161, a bonding layer 163, and a support member 165. The second electrode 160 may selectively include one or two of the diffusion preventing layer 161, the bonding layer 163, and the supporting member 165. For example, the second electrode 160 may remove at least one of the diffusion prevention layer 161 and the bonding layer 163.

The diffusion preventing layer 161 may include a function of preventing the diffusion of a material contained in the bonding layer 163 with the first electrode 170. The diffusion preventing layer 161 may be electrically connected to the bonding layer 163 and the support member 165. The diffusion barrier layer 161 may include at least one of Cu, Ni, Ti, W, Cr, W, Pt, V, Fe and Mo. The diffusion barrier layer 161 is formed on the second electrode 160, the current spreading layer 130, the second conductivity type semiconductor layer 116, and the active layer 114 by the recess 141 and the insulating layer 143, And may be electrically connected to the first conductive type first semiconductor layer 112.

The bonding layer 163 may be disposed under the diffusion barrier layer 161. The bonding layer 163 may be disposed between the diffusion barrier layer 161 and the support member 165. The bonding layer 163 may include a barrier metal or a bonding metal. For example, the bonding layer 163 may include at least one of Ti, Au, Sn, Ni, Cr, Ga, In, Bi, Cu, Ag, Nb, Pd and Ta.

The support member 165 may be a metal or a carrier substrate. For example, the support member 165 may be a semiconductor substrate (e.g., Si, Ge, GaN) doped with Ti, Cr, Ni, Al, Pt, Au, W, Cu, Mo, Cu-W, , GaAs, ZnO, SiC, SiGe, or the like), and may be formed as a single layer or a multilayer.

Referring to Figures 7 and 8, the substrate (5 in Figure 6) may be removed from the light emitting structure 110. The method of removing the substrate (5 in FIG. 7) may be a chemical etching method, but is not limited thereto.

A pad 177 may be formed over the capping layer 175 exposed from the light emitting structure 110. The upper surface of the capping layer 175 may be exposed from the light emitting structure 110 through an etching process and the exposed capping layer 175 may be located in at least one edge region of the light emitting device. But is not limited thereto.

The pad 177 may be spaced apart from the light emitting structure 110. The pad 177 may be disposed outside the light emitting structure 110. The pad 177 may be disposed on the first capping layer 175 located outside the light emitting structure 110. The pad 177 may include at least one of Ti, Cr, Ni, Al, Pt, Au, W, Cu, Mo, Cu-W, Be, Zn and Ge. .

The first conductive type first semiconductor layer 112 may have a light extracting pattern 113 for improving light extraction efficiency. The light extracting pattern 113 may be formed on the upper surface of the first conductive type first semiconductor layer 112 exposed by removing the substrate (5 of FIG. 6). The light extracting pattern 113 may be formed by a method such as PEC, but is not limited thereto. The light extracting patterns 113 may be formed to have regular shapes and arrangements, and may have irregular shapes and arrangements. For example, the cross section of the light extracting pattern 113 may be polygonal, circular or elliptical, but is not limited thereto. The light extracting pattern 113 refracts light, which is totally reflected from the upper surface of the first conductive type semiconductor layer 112 and reabsorbed, out of the light generated from the active layer 114 to improve light extraction efficiency .

The first conductive semiconductor structure may be disposed between the light emitting structure 110 and the second electrode 160 to improve light intensity by reducing light absorption.

In addition, in the ultraviolet light emitting device 100 of the embodiment, the first conductive semiconductor structure may be disposed between the light emitting structure 110 and the second electrode 160 to improve the current spreading effect.

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

9, the light emitting device 200 according to another embodiment includes a second electrode 260 disposed on the upper portion of the light emitting structure 110, a first electrode 260 disposed on the lower portion of the light emitting structure 110, Electrode 270 as shown in FIG. In the light emitting device 200 according to another embodiment, the current spreading layer 130 may be disposed between the first conductive type GaN first semiconductor layer 112 and the first electrode 270.

In another embodiment, the current blocking layer 145 and the channel layer 146 may be disposed below the light emitting structure 110.

The current blocking layer 145 is SiO _2, SiO _x, SiO _x N _y, Si ₃ N _4, Al ₂ O _3, TiO ₂ may include at least one of the the light emitting structure 110. The first electrode At least one may be formed between the first electrode 270 and the second electrode 270. The current blocking layer 145 may overlap the second electrode 260 disposed on the light emitting structure 110 in a direction perpendicular to the second electrode 260. When the second electrode 260 and the first electrode 270 are vertically overlapped, the second electrode 260 and the first electrode 270 have the shortest distance in the vertically overlapped region, Current crowding may occur in vertically superimposed regions. The current density may cause droop of light depending on the driving time of the light emitting device due to the combination of electrons and electrons in the local region. The current blocking layer 145 may cut off the current of the shortest distance vertically overlapping the second electrode 260 and the first electrode 270 to diffuse it to another path. In the light emitting device 200 of the embodiment, the current blocking layer 145 may be disposed in a region where the first and second electrodes 270 and 260 are vertically overlapped to improve current density and droop of light.

The channel layer 146 may be disposed along the lower edge of the light emitting structure 110. The channel layer 146 may be, but is not limited to, a top view in the form of a ring, a loop, or a frame. The channel layer 146 is an ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, SiO 2, SiO x, SiO x N y, Si 3 N 4, at least one of Al ₂ O _3, TiO ₂ And may be arranged in a single layer or in multiple layers. A portion of the channel layer 146 may be disposed below the second conductive semiconductor layer 116 and another portion of the channel layer 146 may be disposed further outward than a side surface of the light emitting structure 110 The structure of the second electrode 260 excluding the connection structure and the position between the second electrode 260 and the light emitting structure 110 corresponds to the ultraviolet light emitting device 100 of the embodiment shown in Figs. 1 to 8, .

The first electrode 270 may be disposed below the current spreading layer 130 and the second electrode 260 may be disposed over the light emitting structure 110.

The current spreading layer 130 of another embodiment may be in ohmic contact with the light emitting structure 110 and the first electrode 270. The current spreading layer 130 is composed of an AlGaN-based semiconductor layer, and the decrease in luminous intensity due to light absorption can be improved. For example, the current spreading layer 130 can improve light absorption of ultraviolet wavelengths. The current spreading layer 130 is formed of an AlGaN-based semiconductor layer including a first conductive dopant between the second conductive type semiconductor layer 116 and the first electrode 270 to improve ohmic contact and current spreading can do.

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

The light emitting device package 300 according to the embodiment includes a package body 305, a first lead electrode 313 and a second lead electrode 314 provided on the package body 305, And a molding member 330 surrounding the ultraviolet light emitting device 100 is formed on the first lead electrode 313 and the second lead electrode 314. The ultraviolet light emitting device 100 is electrically connected to the first lead electrode 313 and the second lead electrode 314, .

The first lead electrode 313 and the second lead electrode 314 are electrically isolated from each other and serve to supply power to the ultraviolet light emitting device 100. The first lead electrode 313 and the second lead electrode 314 may include a function of increasing light efficiency by reflecting the 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 313 or the second lead electrode 314 by a wire, flip chip or die bonding method.

The ultraviolet light emitting device 100 may be an ultraviolet light emitting device 100 according to the embodiment of FIGS. 1 to 8, but it is not limited thereto, and may be an ultraviolet light emitting device 200 according to another embodiment of FIG.

The molding member 330 may include a phosphor 332 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 330 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.

130: current blocking layer
131: first conductive type second semiconductor layer
133: First conductive type third semiconductor layer
135: first conductive type fourth semiconductor layer

Claims (6)

A light emitting structure including a first conductive type first semiconductor layer, an active layer, and a second conductive type semiconductor layer;
A first electrode under the light emitting structure; And
And a current spreading layer in contact with the light emitting structure and the first electrode,
Wherein the light emitting structure and the current spreading layer are made of AlGaN series,
Wherein the current spreading layer includes a first semiconductor layer of a first conductivity type, a third semiconductor layer of a first conductivity type, and a fourth semiconductor layer of a first conductivity type, The first conductive type third semiconductor layer is disposed between the second semiconductor layer and the first conductive type fourth semiconductor layer, and the first conductive type third semiconductor layer is lower than the first conductive type second semiconductor layer and the first conductive type fourth semiconductor layer And the first conductivity type third semiconductor layer has a composition formula of Al _d Ga _1-d N (0.02 _{? D} ? 0.07). The method according to claim 1,
And the thickness of the first conductive type third semiconductor layer is 10 nm to 20 nm. The method according to claim 1,
Wherein the first conductive type third semiconductor layer comprises a doping concentration of 1.0 x 10 ¹⁹ atoms / cm 3 to 5.0 x 10 ¹⁹ atoms / cm 3. The method according to claim 1,
Wherein the first conductive type second semiconductor layer is in direct contact with the second conductive type semiconductor layer,
The first conductive type fourth semiconductor layer is in direct contact with the first electrode, and the first conductive type second semiconductor layer and the first conductive type fourth semiconductor layer Al _c Ga _1-c N (0 < _c ? ). &Lt; / RTI &gt; 5. The method of claim 4,
Wherein the first conductive type second semiconductor layer and the first conductive type fourth semiconductor layer have a thickness of 1 nm to 3 nm. 12. A light emitting device package comprising the ultraviolet light emitting element according to any one of claims 1 to 11.

Images