In describing an embodiment according to the invention, in the case of being described as being formed "above" or "below" each element, the upper (upper) or lower (lower) Directly contacted or formed such that one or more other components are disposed between the two components. Also, in the case of "upper (upper) or lower (lower)", it may include not only an upward direction but also a downward direction based on one component.
1 is a cross-sectional view showing a light emitting device according to the first embodiment, Figure 2 is a plan view showing a light emitting device according to the first embodiment.
1 and 2, the light emitting device 1 according to the first embodiment may include a support substrate 10, a reflective layer 16, a light emitting structure 30, and an electrode 46.
In addition, the light emitting device 1 according to the first embodiment may further include a bonding layer 13, a current blocking layer 22, and first and second protective layers 19 and 40, but the present invention is not limited thereto. I never do that.
The support substrate 10, the bonding layer 13, and the reflective layer 16 may form an electrode layer 15. For example, a constant voltage power is supplied to the support substrate 10 and a negative voltage power is supplied to the electrode 46, so that a current flows in the light emitting structure 30, thereby generating light in the light emitting structure 30. Can be.
Therefore, the support substrate 10, the bonding layer 13, and the reflective layer 16 may be formed of at least a conductive material through which current can flow, but are not limited thereto.
The support substrate 10 may support a plurality of layers formed thereon. The support substrate 10 may be formed of a conductive metal material or a semiconductor material. Dopants may be included in the semiconductor material to have conductivity. The support substrate 10 may be formed of a material having high electrical conductivity and thermal conductivity.
As the metal material, for example, titanium (Ti), chromium (Cr), nickel (Ni), aluminum (Al), platinum (Pt), gold (Au), tungsten (W), copper (Cu), copper At least one selected from the group consisting of an alloy (Cu Alloy), molybdenum (Mo), and copper-tungsten (Cu-W) may be used, but is not limited thereto.
At least one selected from the group consisting of, for example, Si, Ge, GaAs, GaN, ZnO, SiGe, and SiC may be used as the semiconductor material, but is not limited thereto.
The support substrate 10 may be plated and / or deposited under the light emitting structure 30, or may be attached in the form of a sheet, but is not limited thereto.
The bonding layer 13 may be formed on the support substrate 10. The bonding layer 13 is a bonding layer, and is formed between the reflective layer 16 and the support substrate 10. The bonding layer 13 may serve as a medium for enhancing adhesion between the reflective layer 16 and the support substrate 10.
The bonding layer 13 may include a barrier metal or a bonding metal. The bonding layer 13 may be formed of a metal material having high adhesion and thermal conductivity. The bonding layer 13 may comprise, for example, a single layer or two or more laminations selected from the group consisting of Ti, Au, Sn, Ni, Nb, Cr, Ga, In, Bi, Cu, Ag and Ta. This is not limitative.
A barrier layer (not shown) may be additionally formed on the bonding layer 13, but is not limited thereto. The barrier layer is diffused into the reflective layer 16 or the light emitting structure 30 on which the bonding layer 13 and the material included in the support substrate 10 are formed. It is possible to prevent the electrical characteristics and / or the optical characteristics of the deterioration. The barrier layer may be formed to contact the bottom surface of the reflective layer 16, but is not limited thereto.
The bonding layer 13 may include, for example, a single layer or two or more laminations selected from the group consisting of Ti, Au, Sn, Ni, Nb, Cr, Ga, In, Bi, Cu, Ag, and Ta. However, this is not limitative. The barrier layer may include, but is not limited to, a single layer or two or more laminates selected from the group consisting of Ni, Pt, Ti, W, V, Fe, and Mo.
The upper surface of the bonding layer 13 may be formed so that the central region protrudes in the direction of the light emitting structure 30 compared to the peripheral region. In other words, although the upper surface of the central region may be located higher from the rear surface of the bonding layer 13 than the upper surface of the peripheral region, the bonding layer 13 is not limited thereto.
The reflective layer 16 may be formed on the bonding layer 13. The back surface of the reflective layer 16 may be formed to correspond to the top surface of the bonding layer 13, but is not limited thereto. The rear surface of the reflective layer 16 may be formed so that the peripheral area protrudes in the direction of the bonding layer 13 compared to the central area.
The reflective layer 16 may be formed between the bonding layer 13 and the light emitting structure 30, but is not limited thereto. If the support substrate 10 is plated and / or deposited directly on the reflective layer 16, the bonding layer 13 is not necessary. In this case, the reflective layer 16 may be formed between the support substrate 10 and the light emitting structure 30.
The reflective layer 16 may reflect light incident from the light emitting structure 30, thereby improving light extraction efficiency. In addition, the reflective layer 16 may be in ohmic contact with the light emitting structure 30 so that a current flows more easily to the light emitting structure 30.
When the reflective layer 16 does not have an ohmic contact function, an ohmic contact layer may be further formed on the reflective layer 16 in contact with the light emitting structure 30, but is not limited thereto.
The reflective layer 16 may be formed of a single layer in which the reflective material and the ohmic contact material are mixed.
At least one or more alloys selected from the group consisting of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au and Hf are used as the reflective material. I never do that. As the ohmic contact material, a transparent conductive material and a metal material may be selectively used. That is, the transparent conductive material may include, for example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), May comprise at least one selected from the group consisting of indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrOx, RuOx and RuOx / ITO, This is not limitative. As the metal material, for example, at least one selected from the group consisting of Ni, Ag, Ni / IrOx / Au, and Ni / IrOx / Au / ITO may be used.
For example, the reflective layer 16 may be formed of a multilayer including any one of IZO / Ni, AZO / Ag, IZO / Ag / Ni, and AZO / Ag / Ni.
The reflective layer 16 may be in ohmic contact with at least the light emitting structure 30. Accordingly, the light emission efficiency may be improved by smoothly supplying current to the light emitting structure 30 in ohmic contact with the reflective layer 16.
In order to reflect all the light from the light emitting structure 30, the reflective layer 16 may have an area larger than at least the light emitting structure 30, specifically, the active layer 34.
The first passivation layer 19 may be formed on the peripheral area of the bonding layer 13. As illustrated in FIG. 2, the first protective layer 19 may be formed along the circumferential region of the bonding layer 13, but is not limited thereto.
An upper surface of the reflective layer 16 and an upper surface of the first protective layer 19 may be formed at the same position, but are not limited thereto.
The reflective layer 16 may be formed inside the first protective layer 19, that is, on the central region of the bonding layer 13.
Alternatively, the reflective layer 16 may be formed on the peripheral region as well as the central region of the bonding layer 13. In this case, the reflective layer 16 may be formed between the first protective layer 19 and the bonding layer 13, but is not limited thereto.
The first passivation layer 19 may be formed of a single layer or multiple layers of a transparent conductive material, a metal material, or a transparent insulating material, but is not limited thereto. The metal material may be a material capable of ohmic contact with the light emitting structure 30 and having excellent electrical conductivity, but is not limited thereto.
Examples of the transparent conductive material include indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), and indium gallium (IGTO). At least one selected from the group consisting of tin oxide), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrOx, RuOx, and RuOx / ITO may be used, but is not limited thereto. At least one selected from the group consisting of Au, Ti, Ni, Cu, Al, Cr, Ag, and Pt may be used as the metal material, but is not limited thereto. For example, at least one selected from the group consisting of SiO 2, SiO x, SiO x N y, Si 3 N 4, and Al 2 O 3 may be used as the transparent insulating material, but is not limited thereto.
When the first protective layer 19 is formed of a transparent insulating material, the separation distance between the outer surface of the reflective layer 16 and the outer surface of the light emitting structure 30 is further increased to give the reflective layer 16 and the light emitting structure ( 30) It can prevent the electric short by the foreign material between.
When the first passivation layer 19 is formed of a transparent conductive material, current flows through the reflective layer 16 and the first passivation layer 19, so that light is also generated in the peripheral region of the light emitting structure 30. The light efficiency can be improved. In addition, the light generated by the light emitting structure 30 is reflected by the reflective layer 16 formed below the first protective layer 19 through the first protective layer 19, thereby improving light extraction efficiency. Can be.
When the first passivation layer 19 is formed of a metal material, current may be more easily supplied to the light emitting structure 30 through the first passivation layer 19, whereby light efficiency may be further improved.
In the drawing, the first protective layer 19 is formed to have the same width, but the embodiment is not limited thereto.
The first protective layer 19 may be formed in a shape that decreases in width from the outer surface to the inner surface.
Alternatively, the first passivation layer 19 may have a shape in which its upper surface is flat while its width decreases from the outer surface to the inner surface. In this case, the back and side surfaces of the first protective layer 19 may have a straight inclined shape or a round inclined shape, but is not limited thereto.
The first passivation layer 19 may include an inner region vertically overlapping the light emitting structure 30 and an outer region extending outwardly from the inner region and not vertically overlapping the light emitting structure 30. have. The outer region may be referred to as a first region, and the inner region may be referred to as a second region.
The second protective layer 40 may be formed on the outer region of the first protective layer 19, but is not limited thereto.
The light emitting structure 30 may be formed on the reflective layer 16 and the first protective layer 19. The light emitting structure 30 may include, but is not limited to, a first conductivity type semiconductor layer 31, an active layer 34, and a second conductivity type semiconductor layer 37.
The first conductive semiconductor layer 31 is formed on the reflective layer 16 and the first protective layer 19, and the active layer 34 is formed on the first conductive semiconductor layer 31. The second conductivity type semiconductor layer 37 may be formed on the active layer 34.
For example, the first conductivity-type semiconductor layer 31 may include a p-type dopant, and the second conductivity-type semiconductor layer 37 may include an n-type dopant, but is not limited thereto. That is, the first conductivity type semiconductor layer 31 may include an n-type dopant, and the second conductivity type semiconductor layer 37 may include a p-type dopant.
Another semiconductor layer may be formed below the first conductivity type semiconductor layer 31 and above the second conductivity type semiconductor layer 37, but is not limited thereto.
Sides of the light emitting structure 30 may be formed to be vertical or inclined by an etching for dividing a plurality of chips into individual chip units.
When the side surface of the light emitting structure 30 is formed to be inclined, the light generated by the light emitting structure 30 may proceed in a more upward direction. When the side surface of the light emitting structure 30 is formed to be inclined, the area is gradually increased from the second conductive semiconductor layer 37 to the active layer 34 and the first conductive semiconductor layer 31. Can be.
In the drawing, the side surface of the light emitting structure 30 is formed in a straight shape, but is not limited thereto. For example, the side surface of the light emitting structure 30 may be formed in a round shape.
The light emitting structure 30 may include a compound semiconductor material of a plurality of Group 2 to 6 elements.
The first conductivity type semiconductor layer 31 may be formed on the reflective layer 16 and the first protective layer 19. If there is no other semiconductor layer on the first conductivity type semiconductor layer 31 and the reflective layer 16, the rear surface of the first conductivity type semiconductor layer 31 is the top surface of the reflective layer 16 and the first protective layer. It may be formed in contact with the top surface of the layer (19).
The first conductive semiconductor layer 31 may be a p-type semiconductor layer including a p-type dopant, but is not limited thereto. The first conductivity type semiconductor layer 31 may be formed of a compound semiconductor of Group 2 to Group 6 elements. The first conductive semiconductor layer 31 may include, for example, one selected from the group consisting of GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. It is not limited. The p-type dopant may include one selected from the group consisting of Mg, Zn, Ga, Sr, and Ba, but is not limited thereto. The first conductivity type semiconductor layer 31 may be formed as a single layer or a multilayer, but is not limited thereto.
The first conductive semiconductor layer 31 serves to supply a plurality of first carriers, for example, holes, to the active layer 34.
The active layer 34 may be formed on the first conductivity type semiconductor layer 31.
Although not shown, an electron blocking layer may be further formed between the first conductivity type semiconductor layer 31 and the active layer 34, but is not limited thereto. The electron blocking layer may prevent electrons supplied to the active layer 34 from being transferred to the first conductive semiconductor layer 31. The electron blocking layer may be GaN, AlGaN or InAlGaN, but is not limited thereto. Therefore, more holes and electrons supplied to the active layer 34 by the electron blocking layer may be recombined, thereby improving light emission efficiency of the light emitting device 1.
The active layer 34 may include any one of a multi quantum well structure (MQW), a quantum dot structure, and a quantum line structure, but is not limited thereto. The active layer 34 may be formed in a cycle of a well layer and a barrier layer using a compound semiconductor material of Group 2 to Group 6 elements. Compound semiconductor materials for use as the active layer 34 may be GaN, InGaN, AlGaN. The active layer 34 may include, but is not limited to, a period of an InGaN well layer / GaN barrier layer, a period of an InGaN well layer / AlGaN barrier layer, a period of an InGaN well layer / InGaN barrier layer, and the like. .
The active layer 34 recombines holes supplied from the first conductive semiconductor layer 31 and a plurality of second carriers, that is, electrons, supplied from the second conductive semiconductor layer 37. In addition, light having a wavelength corresponding to a band gap determined by the compound semiconductor material of the active layer 34 may be generated.
The second conductivity type semiconductor layer 37 may be formed on the active layer 34. The second conductivity-type semiconductor layer 37 may be an n-type semiconductor layer including an n-type dopant, but is not limited thereto. The second conductivity-type semiconductor layer 37 may be formed of a compound semiconductor of Group 2 to Group 6 elements. The second conductive semiconductor layer 37 may include, for example, one selected from the group consisting of GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. This is not limitative. The n-type dopant may include Si, Ge, Sn, Se, and Te, but is not limited thereto. The second conductivity type semiconductor layer 37 may be formed as a single layer or a multilayer, but is not limited thereto.
In the growth of the light emitting structure 30, the second conductive semiconductor layer 37, the active layer 34, and the first conductive semiconductor layer 31 may be grown in this order, but are not limited thereto.
A light extraction structure 43 may be formed on the top surface of the second conductive semiconductor layer 37 for light extraction efficiency. The light extraction structure 43 may be formed in a random pattern formed by wet etching, or may be formed in a periodic pattern such as a photonic crystal structure formed by a patterning process, but is not limited thereto.
The light extraction structure 43 may have a concave shape and a convex shape periodically. The concave shape and the convex shape may have, for example, a round face or may have both inclined faces that meet at a vertex.
An electrode 46 may be formed on the second conductivity type semiconductor layer 37. Since the electrode 46 is formed of an opaque metal material that absorbs or blocks light, the area of the electrode 46 is preferably as narrow as possible. However, when the area of the electrode 46 is narrowed, the area for supplying current to the light emitting structure 30 may be reduced, so that the size of the electrode 46 preferably has a threshold. The area of the electrode 46 may be, for example, in a range of 2% to 20% of the area of the second conductive semiconductor layer 37, but is not limited thereto.
The electrode 46 may be formed in a single layer or a multilayer structure including at least one selected from the group consisting of Au, Ti, Ni, Cu, Al, Cr, Ag, and Pt.
Although not shown, a reflective layer 16 made of a reflective material may be further formed on at least the side of the electrode 46, but is not limited thereto. For example, at least one or two or more alloys selected from the group consisting of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf may be used as the reflective material, but is not limited thereto. I never do that.
Alternatively, the electrode 46 itself may be formed of a material having excellent reflectivity and excellent electrical conductivity.
The light extracting structure 43 may be formed on the upper surface of the second conductivity-type semiconductor layer 37 except for the electrode 46 or on the entire region of the upper surface of the second conductivity-type semiconductor layer 37. This is not limitative.
When the light extraction structure 43 is formed on the upper surface of the second conductivity-type semiconductor layer 37 corresponding to the electrode 46, the electrode 46 is stronger than the second conductivity-type semiconductor layer 37. It can be attached to.
The second passivation layer 40 may be formed on the light emitting structure 30. For example, a second passivation layer 40 may be formed on at least a side surface of the light emitting structure 30. Specifically, one end of the second protective layer 40 is formed in the circumferential region of the upper surface of the second conductive semiconductor layer 37, and the side surface of the second conductive semiconductor layer 37 and the active layer ( The other end may be formed on the outer region of the first passivation layer 19 via or across the side of the first conductive semiconductor layer 31 and the side of the first conductive semiconductor layer 31, but is not limited thereto.
The second protective layer 40 may prevent electrical short between the light emitting structure 30 and the support substrate 10, and may protect the light emitting structure 30 from an external impact. The second protective layer 40 may be formed of a material having excellent transparency and insulation. The second protective layer 40 may include, but is not limited to, for example, one selected from the group consisting of SiO 2, SiO x, SiO x N y, Si 3 N 4, TiO 2, and Al 2 O 3.
The second protective layer 40 may be formed of the same or different material as the first protective layer 19.
When the first and second protective layers 19 and 40 are formed of the same material, for example, the first and second protective layers 19 and 40 may be formed of a transparent insulating material. The first passivation layer 19 and the second passivation layer 40 formed of a transparent insulating material may also be formed of different kinds of materials. For example, the first protective layer 19 may be formed of silicon oxide, and the second protective layer 40 may be formed of silicon nitride, but is not limited thereto.
When the first and second protective layers 19 and 40 are formed of different materials, for example, the first protective layer 19 is formed of a transparent conductive material, and the second protective layer 40 is formed of a transparent insulating material. It may be formed, but not limited thereto.
Meanwhile, the current blocking layer 22 may be disposed to vertically overlap with the electrode 46. The current blocking layer 22 may be formed in the first conductivity type semiconductor layer 31, but is not limited thereto.
The current blocking layer 22 may be formed to protrude from the rear surface of the first conductive semiconductor layer 31 to the inside of the first conductive semiconductor layer 31.
Grooves 110 (refer to FIG. 6) recessed inward may be formed on the rear surface of the first conductive semiconductor layer 31. In the drawing, the inner surface and the bottom surface of the groove 110 are formed in an angled shape, but the embodiment is not limited thereto. The inner surface and the bottom surface of the groove 110 may be formed in a round shape.
The current blocking layer 22 may be formed in the groove 110 formed on the rear surface of the first conductive semiconductor layer 31.
A plurality of nanoparticles 25 may be formed on the bottom surface of the groove 110. That is, the nano tactic may be formed on the current blocking layer 22 in the groove 110.
The nanoparticle 25 may be a metal material having excellent electrical conductivity. For example, the nanoparticle 25 may include, but is not limited to, at least one selected from the group consisting of Al, Au, Pt, and Ag, or an alloy thereof.
When the size of the nanoparticles 25 is too large, it is preferable that particles of 5 nm to 15 nm are used because they absorb or reflect light to prevent light extraction.
The nanoparticle 25 may be formed in a dot shape, but is not limited thereto.
The nanoparticle 25 may be a medium for generating surface plasmon (wsp) by being excited by light generated in the active layer 34.
Surface plasmon (wsp) refers to the collective charge density oiscillation of electrons occurring on the metal thin film surface.
Resonance is generated in the electrons and holes of the active layer 34 in the surface plasmon (wsp) to amplify the recombination rate of the electrons and holes, so that the luminous efficiency of the active layer 34 can be significantly increased.
Surface plasmons (wsp) may be generated by the interaction between the light generated in the active layer 34 and the nanoparticles 25. Since the generated electron vibration energy of the surface plasmon (wsp) and the exciton hole-electron pair energy of the active layer 34 are similar to each other, the exciton dipole energy of the active layer 34 is nanoparticles ( 25) may be electrons to the surface plasmon (wsp).
Electron-hole recombination produces surface plasmons (wsp) instead of photons, and these surface plasmons (wsp) couple with light. The coupling process of the active layer 34 and the surface plasmon (wsp) is much faster than the recombination rate of the exciton dipoles in the active layer 34. Therefore, this new recombination method can improve the spontaneous recombination rate, that is, the spontaneous emission rate, and increase the light emission intensity due to light absorption of the light emitting device 1.
In conclusion, the internal quantum efficiency greatly depends on the spontaneous recombination rate, and the rapid increase in the spontaneous recombination can improve the light emission efficiency of the entire light emitting device.
In order for the surface plasmon (wsp) caused by the nanoparticles 25 to generate resonance in the electrons and holes of the active layer 34, the closer the distance between the nanoparticles 25 and the active layer 34 is, This is not limitative. For example, the distance d between the bottom surface of the groove 110 and the back surface of the active layer 34 may be 3 nm to 30 nm, but is not limited thereto. When the distance d between the bottom surface of the groove 110 and the back surface of the active layer 34 is 50 nm or less, an electrical short between the nanoparticles 25 and the active layer 34 may occur. When the distance d between the bottom surface of the groove 110 and the back surface of the active layer 34 is 50 nm or more, resonance of electrons and holes of the active layer 34 by the nanoparticles 25 may not occur. .
In addition, the height of the groove 110 or the thickness w of the current blocking layer 22 may be 10 nm to 100 nm, but is not limited thereto.
The distance d between the bottom surface of the groove 110 and the back surface of the active layer 34 may be smaller than the height of the groove 110 or the thickness w of the current blocking layer 22. This is not limitative.
The width of the current blocking layer 22 may be greater than or equal to the width of the electrode 46, but is not limited thereto.
The nanoparticles 25 may be formed at regular intervals or randomly formed.
The NATO particles may have a circular shape, but are not limited thereto. For example, the NATO particles may be formed in an oval shape, an polygon having an angle, a star shape, or the like.
The nanoparticle 25 is formed in a single layer, but is not limited thereto. The nanoparticle 25 may be formed in a multilayer structure.
The nanoparticles 25 may be formed in the uppermost region of the groove, and the current blocking layer 22 and the nanoparticles 25 may be alternately stacked in a downward direction, but the present invention is not limited thereto.
When the nanoparticles 25 are not present, current does not flow between the electrode 46 and the current blocking layer 22 due to the current blocking layer 22 so as to overlap the current blocking layer 22 vertically. Almost no light is generated in the active layer 34.
However, when the nanoparticle 25 is formed between the current blocking layer 22 and the first conductivity-type semiconductor layer 31 adjacent to the active layer 34, as shown in FIG. 3, the nanoparticle ( 25) surface plasmon (wsp) is generated, and the surface plasmon (wsp) facilitates recombination of electrons and holes in the active layer 34, and thus between the electrode 46 and the current blocking layer 22 Light may also be generated in the active layer 34.
However, the amount of light generated in the active layer 34 between the electrode 46 and the current blocking layer 22 is an active layer corresponding to a region where the electrode 46 and the current blocking layer 22 do not vertically overlap. It may be less than the amount of light generated in (34), but is not limited thereto. Here, the active layer 34 corresponding to the region where the current blocking layer 22 does not vertically overlap is referred to as a first light generating region, and an active layer between the electrode 46 and the current blocking layer 22 is formed. 34 may also be referred to as a second light generating region.
In the active layer 34 corresponding to a region where the current blocking layer 22 does not vertically overlap, the amount of light may be enriched by the current caused by the reflective layer 16 and the electrode 46. However, in the active layer 34 corresponding to the region in which the current blocking layer 22 vertically overlaps, the current generated by the reflective layer 16 and the electrode 46 hardly flows, so that light generation by the current is almost also generated. However, as described above, light may be generated by amplification of the recombination rate of electrons and holes of the active layer 34 by the surface plasmon (wsp) generated by the nanoparticles 25.
Therefore, by forming the nanoparticles 25 as compared to the case where there is no nanoparticles 25, the luminous efficiency of the active layer 34 can be improved.
As shown in FIG. 4, even though the current blocking layer 22 has a thickness w of 10 nm to 100 nm, as the nanoparticles 25 are disposed adjacent to the reflective layer 16, the reflective layer ( The current of 16 may be supplied to the active layer 34 through the nanoparticles 25 on the surface of the current blocking layer 22. Therefore, light may be generated not only by light generation by the surface plasmon (wsp) but also by current supplied to the active layer 34 through the nanoparticles 25, and thus the luminous efficiency may be further increased.
When the current supplied to the active layer 34 through the reflective layer 16 and the nanoparticles 25 is equal to or greater than the current between the reflective layer 16 and the electrode 46, to prevent concentration of current. Formation of the current blocking layer 22 becomes meaningless.
Accordingly, the current supplied to the active layer 34 through the reflective layer 16 and the nanoparticle 25 may be smaller than the current between the reflective layer 16 and the electrode 46.
The current blocking layer 22 may be formed at the same time as the first passivation layer 19 in a process, or may be formed separately from the first passivation layer 19.
The lower surface of the current blocking layer 22 may be formed to contact the upper surface of the reflective layer 16, but is not limited thereto.
The current blocking layer 22 may be in Schottky contact with the first conductivity type semiconductor layer 31. Accordingly, no current is supplied to the first conductive semiconductor layer 31 which is in Schottky contact with the current blocking layer 22.
Typically, current flows intensively along the shortest path between the reflective layer 16 and the electrode 46.
In order to prevent such current concentration, the current blocking layer 22 may be formed to partially overlap the electrode 46. Current may not flow completely through the current blocking layer 22 or may flow relatively small through the current blocking layer 22. On the contrary, since the current flows completely through the reflective layer 16 in contact with the first conductivity-type semiconductor layer 31, the current flows uniformly to the entire region of the light emitting structure 30, so that the luminous efficiency is improved. Can be improved.
The current blocking layer 22 has a smaller electrical conductivity than the reflective layer 16, has a larger electrical insulating property than the reflective layer 16, or forms a Schottky contact with the first conductive semiconductor layer 31. It can be formed using a material to.
The current blocking layer 22 may be formed of a transparent conductive material or a transparent insulating material, but is not limited thereto. At least one selected from the group consisting of, for example, ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, and ZnO may be used as the transparent conductive material, but is not limited thereto. The transparent insulating material may include, for example, at least one selected from the group consisting of SiO 2, SiO x, SiO x N y, Si 3 N 4, and Al 2 O 3.
The current blocking layer 22 is formed in the first conductivity type semiconductor layer 31, but is not limited thereto. That is, the current blocking layer 22 may be formed in the groove 110 or the groove formed in the reflective layer 16, or may be formed in the hole penetrating the upper and lower surfaces of the reflective layer 16, but is not limited thereto. I do not.
The current blocking layer 22 and the first and second protective layers 19 and 40 may be formed of the same insulating material. For example, the current blocking layer 22 and the first and second protective layers 19 and 40 may be formed of a transparent insulating material.
Alternatively, the current blocking layer 22 may be formed of a material different from those of the first and second protective layers 19 and 40. For example, the current blocking layer 22 and the second protective layer 40 may be formed of a transparent insulating material, and the first protective layer 19 may be formed of a transparent conductive material.
For example, the first protective layer 19 may be formed of a metal material, the second protective layer 40 may be formed of a transparent insulating material, and the current blocking layer 22 may be formed of a transparent conductive material. In this case, the reflective layer 16 has a higher ohmic contact characteristic with the first conductive semiconductor layer 31 than the current blocking layer 22, and the first protective layer 19 than the reflective layer 16. The first conductive semiconductor layer 31 may have higher ohmic contact characteristics.
5 to 12 illustrate a process for manufacturing the light emitting device according to the first embodiment.
Referring to FIG. 5, the lower second conductive semiconductor layer 37, the active layer 34, and the first conductive semiconductor layer 31 are sequentially grown on the growth substrate 100 to form the light emitting structure 30. Can be.
The growth substrate 100 is a substrate for growing the light emitting structure 30, and may be formed of a material suitable for growing a semiconductor material, that is, a carrier wafer. In addition, the growth substrate may be formed of a material having a similar lattice constant and thermal stability to the light emitting structure 30, and may be a conductive substrate or an insulating substrate.
The growth substrate 100 may be formed of, for example, at least one of sapphire (Al 2 O 3), SiC, GaAs, GaN, ZnO, Si, GaP, InP, and Ge, but is not limited thereto.
The light emitting structure 30 may include, for example, a metal organic chemical vapor deposition (MOCVD), a chemical vapor deposition (CVD), a plasma chemical vapor deposition (PECVD), and a molecular beam. Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), etc. may be formed using, but is not limited thereto.
A buffer layer (not shown) may be formed between the light emitting structure 30 and the growth substrate 100 to alleviate the lattice constant difference between the light emitting structure 30 and the growth substrate 100.
The second conductivity type semiconductor layer 37 may be formed on the growth substrate 100. The second conductivity-type semiconductor layer 37 may be an n-type semiconductor layer including an n-type dopant.
The active layer 34 is formed on the upper second conductive semiconductor layer 37 and may include any one of a single quantum well structure, a multi-quantum well structure (MQW), a quantum dot structure, or a quantum line structure. This is not limitative.
The active layer 34 recombines the holes supplied from the first conductivity type semiconductor layer 31 and the electrons supplied from the second conductivity type semiconductor layer 37 to recombine the semiconductor of the active layer 34. It is possible to produce light of a wavelength corresponding to the band gap determined by the material.
The first conductivity type semiconductor layer 31 may be formed on the active layer 34. The first conductive semiconductor layer 31 may be a p-type semiconductor layer including a p-type dopant.
Referring to FIG. 6, a groove 110 may be formed on an upper surface of the first conductive semiconductor layer 31 by etching the first conductive semiconductor layer 31.
The groove 110 may have a shape recessed from an upper surface of the first conductivity type semiconductor layer 31.
Referring to FIG. 7, a plurality of nanoparticles 25 may be formed in the groove 110, specifically, on the bottom surface of the groove 110.
The nanoparticle 25 may be formed using a deposition apparatus such as e-beam evaporation, but is not limited thereto.
Referring to FIG. 8, a current blocking layer 22 may be formed on the nanoparticles 25 in the groove 110.
In addition, the first passivation layer 19 may be formed along the circumferential region of the first conductivity type semiconductor layer 31.
The first protective layer 19 and the current blocking layer 22 may be formed simultaneously by the same process or separately by different processes, but are not limited thereto.
The current blocking layer 22 may be formed to spatially overlap at least a portion of the electrode 46 to be formed later.
The current blocking layer 22 may serve to block a current supplied to the first conductive semiconductor layer 31 or to reduce the amount of current.
Thus, the current may not flow completely through the current blocking layer 22 or may flow relatively small through the current blocking layer 22. On the contrary, since the current flows well to the first conductivity-type semiconductor layer 31 except for the current blocking layer 22, the current flows uniformly to the entire region of the light emitting structure 30, thereby improving luminous efficiency. Can be.
The current blocking layer 22 may be formed of a transparent conductive material or a transparent insulating material, but is not limited thereto. At least one selected from the group consisting of, for example, ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, and ZnO may be used as the transparent conductive material, but is not limited thereto. The transparent insulating material may include, for example, at least one selected from the group consisting of SiO 2, SiO x, SiO x N y, Si 3 N 4, and Al 2 O 3.
If the electrode 46 is formed in plural, the current blocking layer 22 may also be formed in plural to correspond to each of the electrodes 46.
The first passivation layer 19 may be formed of a single layer or multiple layers of a transparent conductive material, a metal material, or a transparent insulating material, but is not limited thereto. The metal material may be a material capable of ohmic contact with the light emitting structure 30 and having excellent electrical conductivity, but is not limited thereto.
Examples of the transparent conductive material include indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), and indium gallium (IGTO). At least one selected from the group consisting of tin oxide), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrOx, RuOx, and RuOx / ITO may be used, but is not limited thereto. At least one selected from the group consisting of Au, Ti, Ni, Cu, Al, Cr, Ag, and Pt may be used as the metal material, but is not limited thereto. For example, at least one selected from the group consisting of SiO 2, SiO x, SiO x N y, Si 3 N 4, and Al 2 O 3 may be used as the transparent insulating material, but is not limited thereto.
Referring to FIG. 9, the reflective layer 16, the bonding layer 13, and the support substrate 10 are disposed on the current blocking layer 22, the first protective layer 19, and the first conductive semiconductor layer 31. ) May be formed.
The electrode layer 15 may be formed by the reflective layer 16, the bonding layer 13, and the support substrate 10, but is not limited thereto.
The reflective layer 16 may form an ohmic contact with the first conductive semiconductor layer 31. The reflective layer 16 may be formed of an excellent reflective material capable of reflecting light. The reflective layer 16 may be formed of a metal material having excellent electrical conductivity to serve as an electrode.
The electrode layer 15 may include a single layer or a multilayer in which an ohmic contact material and a reflective material are mixed on the first conductive semiconductor layer 31.
As the reflective material, at least one or more alloys selected from the group consisting of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au and Hf are used. As the ohmic contact material, a conductive material and a metal material may be selectively used. The ohmic contact material may be at least one of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO) tin oxide, AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IrOx, RuOx, RuOx / ITO, Ni, Ag, Ni / IrOx / Au and Ni / IrOx / May be used.
The bonding layer 13 may be formed to enhance the adhesive force between the support substrate 10 and the reflective layer 16. The substrate may be attached to the reflective layer 16 by the bonding layer 13.
The bonding layer 13 may include, for example, at least one selected from the group consisting of Ti, Au, Sn, Ni, Nb, Cr, Ga, In, Bi, Cu, Ag, and Ta.
The support substrate 10 may not only support a plurality of layers formed thereon but also have a function as an electrode. The support substrate 10 may supply power to the light emitting structures 30 and 30 together with the electrode 46.
The support substrate 10 is, for example, titanium (Ti), chromium (Cr), nickel (Ni), aluminum (Al), platinum (Pt), gold (Au), tungsten (W), copper (Cu) , Molybdenum (Mo) and copper-tungsten (Cu-W).
The support substrate 10 may be plated and / or deposited on the light emitting structure 30, or may be attached in the form of a sheet, but is not limited thereto.
Referring to FIG. 10, the growth substrate 100 may be flipped 180 ° and then the growth substrate 100 may be removed.
The growth substrate 100 may be removed by a laser lift off (LLO), chemical etching (CLO, chemical lift off), or a physical polishing method, but is not limited thereto.
Subsequently, mesa etching may be performed such that the side surface of the light emitting structure 30 is inclined. By the mesa etching, the second conductive semiconductor layer 37, the active layer 34, and the first conductive semiconductor layer 31 may be sequentially removed. The mesa etching may be performed until the first protective layer 19 is exposed, but is not limited thereto.
The first protective layer 19 may serve as a stopper to stop the mesa etching. That is, some areas of the second conductive semiconductor layer 37, the active layer 34, and the first conductive semiconductor layer 31 are removed by mesa etching, but are below the first protective layer 19. The reflective layer 16, the bonding layer 13, and the supporting substrate 10 in the layer are not removed.
Referring to FIG. 11, a second passivation layer 40 may be formed on a portion of the light emitting structure 30. That is, the second passivation layer 40 is formed from the circumferential region of the upper surface of the second conductive semiconductor layer 37, on the side of the second conductive semiconductor layer 37, on the side of the active layer 34, and A portion of the upper surface of the first passivation layer 19, that is, an outer region, may be formed via the side surface of the first conductive semiconductor layer 31.
The second protective layer 40 may serve to prevent electrical short between the light emitting structure 30 and the support substrate 10. The second protective layer 40 may be formed of a material having excellent transparency and insulation. The first protective layer 19 may include, but is not limited to, one selected from the group consisting of, for example, SiO 2, SiO x, SiO x N y, Si 3 N 4, TiO 2, and Al 2 O 3.
The second protective layer 40 may be formed of the same material or the same material as the first protective layer 19 and the current blocking layer 22, but is not limited thereto.
Subsequently, an electrode 46 may be formed on the second conductive semiconductor layer 37. The electrode 46 may be disposed to vertically overlap the current blocking layer 22. The electrode 46 may be formed to be the same as or smaller than the size of the current blocking layer 22, but is not limited thereto.
The electrode 46 may be formed in a single layer or a multilayer structure including at least one selected from the group consisting of Au, Ti, Ni, Cu, Al, Cr, Ag, and Pt.
The electrode 46 may be formed first, and then the second protective layer 40 may be formed, but is not limited thereto.
Referring to FIG. 12, an etching process is performed using the second passivation layer 40 and the electrode 46 as a mask, so that the second exposed portion exposed by the second passivation layer 40 and the electrode 46. The light extracting structure 43 may be formed on the upper surface of the two conductive semiconductor layer 37. The light extracting structure 43 may be formed separately on the second conductivity type semiconductor layer 37, but is not limited thereto.
The light extracting structure 43 may scatter light passing through an upper surface of the lower second conductive semiconductor layer 37 to improve light extraction efficiency.
13 is a sectional view showing a light emitting device according to the second embodiment.
The second embodiment is similar to the first embodiment except that the current blocking layer 22a and the nanoparticles 25a are formed in the second conductivity type semiconductor layer 37. In the description of the second embodiment, the same reference numerals are given to components having the same function or the same shape as the first embodiment, and detailed description thereof will be omitted.
Referring to FIG. 13, the light emitting device 1A according to the second embodiment may include a support substrate 10, a reflective layer 16, a light emitting structure 30, and an electrode 46.
In addition, the light emitting device 1A according to the second embodiment may further include a bonding layer 13, a current blocking layer 22a, a nanoparticle 25a, and first and second protective layers 19 and 40. However, this is not limitative.
The current blocking layer 22a may protrude from the upper surface of the reflective layer 16 to the second conductive semiconductor layer 37.
The current blocking layer 22a may be formed such that a rear surface thereof contacts an upper surface of the reflective layer 16 and an upper surface thereof contacts a rear surface of the second conductivity type semiconductor layer 37.
To this end, a groove formed through the first conductive semiconductor layer 31 and the active layer 34 and formed into the second conductive semiconductor layer 37 may be formed.
The current blocking layer 22a may be formed in the groove 110.
A plurality of nanoparticles 25a may be formed on the current blocking layer 22a in the groove 110.
In order for the surface plasmon (wsp) caused by the nanoparticles 25a to cause resonance in the electrons and holes of the active layer 34, the distance d between the nanoparticles 25a and the active layer 34 is closer to each other. Advantageous but not limited to this. For example, the distance d between the nanoparticle 25a and the top surface of the active layer 34 may be 3 nm to 30 nm, but is not limited thereto. When the distance d between the nanoparticle 25a and the top surface of the active layer 34 is 50 nm or less, electrical short between the nanoparticle 25a and the active layer 34 may occur, and the nanoparticles When the distance d between the upper surface of the active layer 34 and 25a is 50 nm or more, resonance of electrons and holes of the active layer 34 by the nanoparticles 25a may not occur.
The current blocking layer 22a may be formed of an excellent transparent insulating material so that the current blocking layer 22a is not electrically shorted between the first and second conductive semiconductor layers 31 and 37. This is not limitative. For example, at least one selected from the group consisting of SiO 2, SiO x, SiO x N y, Si 3 N 4, and Al 2 O 3 may be used as the transparent insulating material, but is not limited thereto.
14 is a sectional view showing a light emitting device according to the third embodiment.
The third embodiment is similar to the second embodiment except that the insulating layer 50 is formed on the side of the current blocking layer 22a. In the description of the third embodiment, the same reference numerals are assigned to components having the same function or the same shape as the second embodiment, and detailed description thereof will be omitted.
Referring to FIG. 14, the light emitting device 1B according to the third embodiment may include a support substrate 10, a reflective layer 16, a light emitting structure 30, and an electrode 46.
In addition, the light emitting device 1B according to the third exemplary embodiment additionally includes the bonding layer 13, the current blocking layer 22a, the nanoparticles 25a, the insulating layer 50, and the first and second protective layers 19, 40) may be further included but is not limited thereto.
The current blocking layer 22a may protrude from the upper surface of the reflective layer 16 to the second conductive semiconductor layer 37.
The current blocking layer 22a may be formed as a single layer or a multilayer of a transparent conductive material or a metal material, but is not limited thereto.
Examples of the transparent conductive material include indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), and indium gallium (IGTO). At least one selected from the group consisting of tin oxide), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrOx, RuOx, and RuOx / ITO may be used, but is not limited thereto. At least one selected from the group consisting of Au, Ti, Ni, Cu, Al, Cr, Ag, and Pt may be used as the metal material, but is not limited thereto.
In this case, the first and second conductivity-type semiconductor layers 31 and 37 may be electrically shorted by the current blocking layer 22a.
Accordingly, the insulating layer 50 may be formed on the side surface of the current blocking layer 22a to prevent electrical short caused by the current blocking layer 22a.
The insulating layer 50 may be formed along the outer circumference of the current blocking layer 22a.
The insulating layer 50 is formed between the current blocking layer 22a and the light emitting structure 30, that is, the first conductive semiconductor layer 31, the active layer 34, and the second conductive semiconductor layer 37. Can be.
The back surface of the insulating layer 50 may be formed to be in contact with the top surface of the reflective layer 16 and the top surface may be in contact with the back surface of the second conductive semiconductor layer 37, but the embodiment is not limited thereto.
The insulating layer 50 may be formed to protrude into the second conductive semiconductor layer 37 from the top surface of the active layer 34 through the first conductive semiconductor layer 31 and the active layer 34. have.
The insulating layer 50 may be formed at a position higher than an upper surface of the active layer 34, but is not limited thereto.
The insulating layer 50 may include, but is not limited to, for example, one selected from the group consisting of SiO 2, SiO x, SiO x N y, Si 3 N 4, TiO 2, and Al 2 O 3.
15 is a cross-sectional view illustrating a light emitting device according to a fourth embodiment.
The fourth embodiment is similar to the third embodiment except that the second reflective layer 53 is formed on the side of the current blocking layer 22b. In the description of the fourth embodiment, the same reference numerals are given to components having the same function or the same shape as the third embodiment, and detailed description thereof will be omitted.
Referring to FIG. 15, the light emitting device 1C according to the fourth embodiment may include a support substrate 10, a first reflective layer 16, a light emitting structure 30, and an electrode 46.
In addition, the light emitting device 1C according to the fourth exemplary embodiment may further include the bonding layer 13, the current blocking layer 22b, the nanoparticles 25b, the second reflecting layer 53, the insulating layer 56, and the first and The second protective layers 19 and 40 may be further included, but are not limited thereto.
The second reflective layer 53 may be formed between the insulating layer 56 and the current blocking layer 22b.
The second reflective layer 53 may improve light efficiency by reflecting light generated by the active layer 34.
The second reflective layer 53 may be formed along the circumference of the outer surface of the current blocking layer 22b.
The second reflective layer 53 may be formed between the outer surface of the current blocking layer 22b and the inner surface of the insulating layer 56.
In order to prevent the second reflective layer 53 from being electrically shorted with the nanoparticles 25b, the top surface of the second reflective layer 53 may be formed at least at a lower position than the nanoparticles 25b. This is not limitative.
The second reflective layer 53 may be formed to be inclined with respect to the upper surface of the first reflective layer 16 in order to efficiently reflect light upward. That is, the second reflective layer 53 may have an inclined side surface.
The current blocking layer 22b and the insulating layer 56 may also have inclined side surfaces.
The second reflective layer 53 may have a shape corresponding to the inclined side surface of the current blocking layer 22b, but is not limited thereto.
The second reflective layer 53 may extend from the first reflective layer 16, but is not limited thereto.
The first and second reflective layers 16 and 53 may be formed simultaneously by the same process or separately by different processes, but are not limited thereto.
The first and second reflective layers 16 and 53 may be formed of the same material or different materials, but are not limited thereto.
Although the first reflective layer 16 may not be formed under the rear surface of the current blocking layer 22b, the present invention is not limited thereto.
The first reflective layer 16 may be formed of an excellent reflective material and / or an excellent ohmic contact material, and the second reflective layer 53 may be formed of an excellent reflective material, but is not limited thereto.
As the reflective material, at least one or more alloys selected from the group consisting of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au and Hf are used.
The ohmic contact materials include indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IZAO), indium gallium zinc oxide (IGZO), and indium gallium tin oxide (IGTO). ), Aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrOx, RuOx, RuOx / ITO, Ni, Ag, Ni / IrOx / Au and Ni / IrOx / Au / ITO At least one selected from the group can be used.
16 is a cross-sectional view illustrating a light emitting device package according to an embodiment.
Referring to FIG. 16, the light emitting device package 200 according to the embodiment may include a body 330, a first lead electrode 310 and a second lead electrode 320 installed on the body 330, and the body ( The light emitting device 1 according to the first to third embodiments installed in the 330 and supplied with power from the first lead electrode 310 and the second lead electrode 320, and the light emitting device 1 It includes a molding member 340 surrounding the).
The body 330 may include a silicon material, a synthetic resin material, or a metal material, and an inclined surface may be formed around the light emitting device 1.
The first lead electrode 310 and the second lead electrode 320 are electrically separated from each other, and provide power to the light emitting device 1.
In addition, the first and second lead electrodes 310 and 320 may increase light efficiency by reflecting light generated from the light emitting device 1, and discharge heat generated from the light emitting device 1 to the outside. You can also do
The light emitting device 1 may be installed on any one of the first lead electrode 310, the second lead electrode 320, and the body 330. It may be electrically connected to the two lead electrodes 310 and 320, but is not limited thereto.
In the embodiment, the light emitting device 1 according to the first embodiment is illustrated, and the first and second lead electrodes 310 and 320 are electrically connected through two wires 350, but the second embodiment is illustrated. In the case of the light emitting device 1 according to the present invention, the first and second lead electrodes 310 and 320 may be electrically connected without the wire 350. In the light emitting device 1 according to the third embodiment, one wire 350 may be used. ) May be electrically connected to the first and second lead electrodes 310 and 320.
The molding member 340 may surround the light emitting device 1 to protect the light emitting device 1. In addition, the molding member 340 may include a phosphor to change the wavelength of light emitted from the light emitting device 1.
The light emitting device package 200 according to the embodiment includes a chip on board (COB) type, the upper surface of the body 330 is flat, the plurality of light emitting devices 1 may be installed on the body 330. have.
