TW201705538A - Light-emitting element with high efficiency reflective structure - Google Patents

Abstract

A light-emitting element includes a reflective layer; a first transparent layer on the reflective layer, wherein the first transparent layer comprises a rod; a light-emitting stacked layer having an active layer on the first transparent layer; and multiple cavities formed in the first transparent layer; wherein the rod is surrounded by the multiple cavities.

Description

Light-emitting element with high efficiency reflective structure

The present invention relates to a light-emitting element, and more particularly to a light-emitting element having a highly efficient reflective structure.

Photoelectric elements, such as light-emitting diodes (LEDs), have been widely used in optical display devices, traffic signs, data storage devices, communication devices, lighting devices, and medical devices. In addition, the LEDs described above can be combined with other components to form a light emitting device. 1 is a schematic structural view of a conventional illuminating device. As shown in FIG. 1, a illuminating device 1 includes a submount 12 having a circuit 14; a solder 16 is located on the subcarrier 12, The solder 16 thus fixes the LED 11 to the sub-carrier 12 and electrically connects the LED 11 to the circuit 14 on the sub-carrier 12; and an electrical connection structure 18 for electrically connecting the electrode 15 of the LED 11 with the sub-carrier 12. The circuit 14 above; wherein the secondary carrier 12 can be a lead frame or a large mounting substrate.

The present application provides a light-emitting element comprising: a reflective layer; a first transparent layer on the reflective layer, comprising a protrusion; a light-emitting layer on the first transparent layer and comprising an active layer; A plurality of apertures are located in the first transparent layer, wherein the projections are surrounded by a plurality of apertures.

The present application also provides a method for fabricating a light-emitting element, comprising the steps of: providing a light-emitting layer stack comprising a second semiconductor layer, an active layer on the second semiconductor layer, and a first semiconductor layer on the active layer; Forming a first transparent layer on the first semiconductor layer; and etching the first transparent layer to form a plurality of holes and a protrusion surrounded by the plurality of holes.

The above features and advantages of the present invention will become more apparent from the following description. In the drawings or the description, the same or similar parts are given the same reference numerals, and in the drawings, the shape or thickness of the elements may be enlarged or reduced. It is to be noted that elements not shown or described in the figures may be in a form known to those skilled in the art.

Fig. 2 is a cross-sectional view showing a light-emitting element of an embodiment of the present application. As shown in FIG. 2, a light-emitting element 2 has a substrate 20; a bonding layer 22 is disposed on the substrate 20; a reflective structure 24 is disposed on the bonding layer 22; and a light-emitting layer 26 is disposed on the reflective structure 24. A first electrode 21 is disposed under the substrate 20; and a second electrode 23 is disposed above the light emitting laminate 26. The light emitting laminate 26 has a first semiconductor layer 262 over the reflective structure 24, an active layer 264 over the first semiconductor layer 262, and a second semiconductor layer 266 over the active layer 264.

The first electrode 21 and/or the second electrode 23 are for receiving an external voltage and may be composed of a transparent conductive material or a metal material. Transparent conductive materials include, but are not limited to, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide. (ZTO), gallium zinc oxide (GZO), zinc oxide (ZnO), gallium phosphide (GaP), indium zinc oxide (IZO), diamond-like carbon film (DLC), indium gallium oxide (IGO), gallium aluminum zinc oxide (GAZO) or a compound of the above materials. Metal materials include, but are not limited to, aluminum (Al), chromium (Cr), copper (Cu), tin (Sn), gold (Au), nickel (Ni), titanium (Ti), platinum (Pt), lead (Pb) , zinc (Zn), cadmium (Cd), antimony (Sb), cobalt (Co) or an alloy of the above materials.

The light emitting laminate 26 has a roughened upper surface 261 and a roughened lower surface 263, which reduces the probability of total reflection and improves light extraction efficiency. The roughened upper surface has a flat portion 265, and the second electrode 23 can be located above the flat portion 265 to enhance the adhesion between the second electrode 23 and the light emitting laminate 26, and reduce the second electrode 23 due to subsequent processes, such as wire bonding. The probability of peeling off from the light-emitting laminate 26 is also high. The material of the light-emitting layer 26 may be a semiconductor material containing more than one element selected from the group consisting of gallium (Ga), aluminum (Al), indium (In), phosphorus (P), nitrogen (N), and zinc (Zn). ), a group of cadmium (Cd) and selenium (Se). The first semiconductor layer 262 is electrically different from the second semiconductor layer 266 for generating electrons or holes. The active layer 124 may emit one or more colored lights, either visible or invisible, and may be of a single heterostructure, a double heterostructure, a double-sided double heterostructure, a multilayer quantum well or a quantum dot.

The reflective structure 24 has a reflective layer 242, a first light transmissive layer 244 and a window layer 248 from the adhesive layer 22 toward the light emitting stack 26. The window layer 248 has a roughened lower surface having a plurality of convex portions 241 and recesses 243. The roughened lower surface further has a flat portion directly under the second electrode 23 for forming an ohmic contact with the first light transmissive layer 244. At least one hole 245 is formed in the first light transmissive layer 244, and the hole 245 may extend downward from the roughened lower surface of the window layer 248 to the reflective layer 242. In another embodiment, the holes 245 may extend downward from the protrusions 241 to the reflective layer 242. The refractive index of the hole 245 is smaller than the refractive index of the window layer 248 and the first light transmissive layer 244. Since the refractive index of the hole 245 is smaller than the refractive index of the window layer 248 and the first light transmissive layer 244, the critical angle of the interface between the window layer 248 and the hole 245 is smaller than the critical angle of the interface between the window layer 248 and the first light transmissive layer 244. Therefore, after the light emitted by the light-emitting layer 26 is directed toward the hole 245, the probability of total reflection at the interface between the window layer 248 and the hole 245 is increased. In addition, the light that is not totally reflected by the window layer 248 and the first light transmissive layer 244 and enters the first light transmissive layer 244, the interface between the first light transmissive layer 244 and the hole 245 also forms total reflection. Thus, the light extraction efficiency of the light-emitting element 2 is improved. The hole 245 may have a funnel shape that is wide and narrow from the cross-sectional view. The reflective structure 24 can further include a second light transmissive layer 246 between the portion of the first light transmissive layer 244 and the window layer 248 to increase the gap between the first light transmissive layer 244 and the window layer 248. Ohmic contact. In another embodiment, the second light transmissive layer 246 can have a hole 245, wherein the hole 245 has a refractive index smaller than that of the window layer 248 and the second light transmissive layer 246. Since the refractive index of the hole 245 is smaller than the refractive index of the window layer 248 and the second light transmissive layer 246, the critical angle of the interface between the second light transmissive layer 246 and the hole 245 is smaller than the interface between the window layer 248 and the second light transmissive layer 246. The critical angle is such that after the light emitted by the light-emitting layer 26 is directed toward the hole 245, the probability of total reflection forming at the interface between the second light-transmitting layer 246 and the hole 245 is increased. In yet another embodiment, the reflective structure 24 may have no window layer 248 formed below the light emitting stack 26. At this time, the roughened lower surface 263 of the light-emitting layer 26 has a plurality of convex portions and concave portions to facilitate the formation of the holes 245.

The window layer 248 is transparent to the light emitted by the light-emitting layer 26 for enhancing the light-emitting efficiency, and the material thereof may be a conductive material, including but not limited to indium tin oxide (ITO), indium oxide (InO), and tin oxide (SnO). , cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), zinc oxide (ZnO), gallium phosphide (GaP), oxidation Indium bismuth (ICO), indium tungsten oxide (IWO), indium titanium oxide (ITiO), indium zinc oxide (IZO), indium gallium oxide (IGO), gallium aluminum oxide (GAZO), or a combination thereof. The height difference h between the concave portion 243 and the convex portion 241 of the roughened lower surface is about 1/3 to 2/3 of the thickness t of the window layer, which facilitates the formation of the hole 245.

The material of the first light transmissive layer 244 and/or the second light transmissive layer 246 is transparent to the light emitted by the light emitting layer 26 to increase ohmic contact and current conduction and diffusion between the window layer 248 and the reflective layer 242, and An Omni-Directional Reflector (ODR) is formed with the reflective layer 242. The material may be a transparent conductive material including, but not limited to, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum oxide zinc (AZO). ), zinc tin oxide (ZTO), gallium zinc oxide (GZO), zinc oxide (ZnO), gallium phosphide (GaP), indium lanthanum oxide (ICO), indium tungsten oxide (IWO), indium titanium oxide (ITiO), Indium zinc oxide (IZO), indium gallium oxide (IGO), gallium aluminum oxide (GAZO) or a combination of the above. The material of the first light transmissive layer 244 is preferably aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), zinc oxide (ZnO), indium zinc oxide (IZO) or a combination thereof. . The method of forming the first light transmissive layer 244 and/or the second light transmissive layer 246 includes physical vapor deposition, such as electron beam evaporation or sputtering. The reflective layer 242 can reflect light from the light emitting stack 26, and the material thereof can be a metal material including, but not limited to, copper (Cu), aluminum (Al), tin (Sn), gold (Au), silver (Ag), lead. (Pb), titanium (Ti), nickel (Ni), platinum (Pt), tungsten (W) or an alloy of the above materials.

The bonding layer 22 can connect the substrate 20 to the reflective structure 24 and can have a plurality of subordinate layers (not shown). The material of the bonding layer 22 may be a transparent conductive material or a metal material, and the transparent conductive material includes, but is not limited to, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide. (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), zinc oxide (ZnO), gallium phosphide (GaP), indium oxide oxide (ICO), indium oxide tungsten (IWO) ), indium titanium oxide (ITiO), indium zinc oxide (IZO), indium gallium oxide (IGO), gallium aluminum oxide (GAZO), or a combination thereof. Metal materials include, but are not limited to, copper (Cu), aluminum (Al), tin (Sn), gold (Au), silver (Ag), lead (Pb), titanium (Ti), nickel (Ni), platinum (Pt) , tungsten (W) or an alloy of the above materials.

The substrate 20 can be used to support the light-emitting laminate 26 and other layers or structures thereon, the material of which can be a transparent material or a conductive material. Transparent materials include, but are not limited to, Sapphire, Diamond, Glass, Epoxy, Quartz, Acryl, Al ₂ O ₃ , Oxidation Zinc (ZnO) or aluminum nitride (AlN). Conductive materials include, but are not limited to, copper (Cu), aluminum (Al), molybdenum (Mo), tin (Sn), zinc (Zn), cadmium (Cd), nickel (Ni), cobalt (Co), diamond-like carbon film (Diamond Like Carbon; DLC), Graphite, Carbon Fiber, Metal Matrix Composite (MMC), Ceramic Matrix Composite (CMC), Germanium (Si), Phosphating Iodine (IP), zinc selenide (ZnSe), gallium arsenide (GaAs), tantalum carbide (SiC), gallium phosphide (GaP), gallium arsenide (GaAsP), zinc selenide (ZnSe), indium phosphide (InP), lithium gallate (LiGaO ₂ ) or lithium aluminate (LiAlO ₂ ).

Figure 3 is a cross-sectional view showing a light-emitting element of another embodiment of the present application. A light-emitting element 3 has a similar structure to the above-described light-emitting element 2, but the second light-transmissive layer 246 of the reflective structure 24 has a plurality of holes 30 such that the second light-transmissive layer 246 has a refractive index of less than 1.4, preferably 1.35. As shown in FIG. 4, the hole 30 is formed by fixing the wafer 4 and depositing the second light-transmissive layer 246 by physical vapor deposition in a specific direction, for example, in a direction D perpendicular to the normal angle of the wafer. The material is on the wafer. The hole 30 is formed because the adjustment of the deposition direction D prevents the material from being deposited to a partial region. Among them, the angle θ is about 60 degrees. The refractive index of the second light transmissive layer 246 formed by the hole 30 is lower than that of the light transmissive layer having no holes, which increases the probability of total reflection between the second light transmissive layer 246 and other layer interfaces, and improves the light emitting element. 3 light output efficiency. The first light transmissive layer 244 may be formed under the second light transmissive layer 246 by a physical vapor phase method or a chemical vapor phase method, and the thickness thereof is greater than the thickness of the second light transmissive layer 246, thereby preventing the material of the reflective layer 242 from diffusing to the second layer. Light transmissive layer 246. The first light transmissive layer 244 does not have holes, and the material of the reflective layer 242 is prevented from diffusing into the holes, and the structure of the reflective layer 242 is destroyed, resulting in a decrease in the reflectance of the reflective layer 242. The first light transmissive layer 244 has a first lower surface 247, and the first lower surface 247 can be ground by chemical mechanical polishing (CMP) to have a center line average roughness (Ra) of about 1 nm to 40 nm. When the reflective layer 242 is formed under the first lower surface 247, the reflective layer 242 can form a surface having a lower centerline average roughness, thereby increasing the reflectivity of the reflective layer 242.

The light-emitting element 3 further has at least one conductive portion 32 between the light-emitting layer 26 and the reflective layer 242. In another embodiment, the conductive portion 32 can be located between the window layer 248 and the reflective layer 242. The conductive portion 32 is used to conduct current, and the material thereof may be a transparent conductive material or a metal material, and the transparent conductive material includes, but is not limited to, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), and cadmium tin oxide (CTO). ), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), zinc oxide (ZnO), gallium phosphide (GaP), indium oxide oxide (ICO), Indium oxide tungsten (IWO), indium titanium oxide (ITiO), indium zinc oxide (IZO), indium gallium oxide (IGO), gallium aluminum oxide (GAZO), or a combination thereof. Metal materials include, but are not limited to, copper (Cu), aluminum (Al), tin (Sn), gold (Au), silver (Ag), lead (Pb), titanium (Ti), nickel (Ni), platinum (Pt) , tungsten (W), germanium (Ge) or an alloy of the above materials.

In this embodiment, the material of the first light transmissive layer 244 and/or the second light transmissive layer 246 may be an insulating material, such as polybenzamine (PI), benzocyclobutene (BCB), perfluorocyclohexane. Alkane (PFCB), Magnesium Oxide (MgO), Su8, Epoxy, Acrylic Resin, Cyclic Olefin Polymer (COC), Polymethyl Methacrylate (PMMA), Polyterephthalic Acid Ethylene glycol (PET), polycarbonate (PC), polyetherimide, fluorocarbon polymer, glass, alumina (Al ₂ O ₃ ), cerium oxide (SiO _x ), titanium oxide (TiO ₂ ), lanthanum oxide (Ta ₂ O ₅ ), tantalum nitride (SiN _x ), magnesium fluoride (MgF ₂ ), spin-on glass (SOG) or tetraethoxy decane (TEOS) .

Figure 5 is a cross-sectional view showing a light-emitting element of another embodiment of the present application. As shown in FIG. 5, a light-emitting element 5 has a substrate 50; a light-emitting layer 52 on the substrate 50; a reflective structure 54 on the light-emitting layer 52; and an electrode 56 on the reflective structure 54. Above. The light emitting layer 52 has a first semiconductor layer 522 over the substrate 50, an active layer 524 over the first semiconductor layer 522, and a second semiconductor layer 526 over the active layer 524. The second semiconductor layer 526 and the active layer 524 are removed to expose the first semiconductor layer 522.

The reflective structure 54 has a window layer 540 on the light emitting layer 52; a first light transmissive layer 542 on the window layer 540; a reflective layer 544 on the first light transmissive layer 542; An insulating layer 546 is located above the reflective layer 544. The window layer 540 has a roughened upper surface 541 having a plurality of convex portions 543 and recesses 545. At least one hole 547 is formed in the first light transmissive layer 542 and is located above the roughened upper surface 541. The refractive index of the hole 547 is smaller than the refractive index of the window layer 540 and the first light transmissive layer 542. In another embodiment, the aperture 547 can extend upward from the recess 545. Since the refractive index of the hole 547 is smaller than the refractive index of the window layer 540 and the first light transmissive layer 542, the critical angle of the interface between the window layer 540 and the hole 547 is smaller than the interface between the window layer 540 and the first light transmissive layer 542. The angle, so that the light emitted by the light-emitting layer 52 is directed toward the hole 547, the probability of total reflection forming at the interface between the window layer 540 and the hole 547 is increased. In addition, the light that is not totally reflected by the window layer 540 and the first light transmissive layer 542 and enters the first light transmissive layer 542, the interface between the first light transmissive layer 542 and the hole 547 also forms total reflection. Therefore, the light-emitting efficiency of the light-emitting element 5 is improved, and the hole 547 can be an inverted funnel shape having a narrow width and a narrow shape as viewed in cross section. Because the light emitted by the light-emitting layer 52 increases the probability of total reflection at the interface between the window layer 540 and the hole 547 and the interface between the first light-transmissive layer 542 and the hole 547, the light is reduced to the electrode 56 and is replaced by the electrode 56. The probability of absorption increases the luminous efficiency of the light-emitting element 5. The first insulating layer 546 can coat the reflective layer 544 such that the reflective layer 544 does not directly contact the electrode 56, and the material of the reflective layer 544 is prevented from diffusing to the electrode 56, reducing the reflectivity of the reflective layer 544. The reflective structure 54 further includes a plurality of channels 549 formed in the first light transmissive layer 542 and the first insulating layer 546, and the electrodes 56 can be electrically connected to the light emitting stack 52 via the vias 549. The reflective structure 54 further includes a second light transmissive layer 548. The second light transmissive layer 548 is located between the portion of the first light transmissive layer 542 and the reflective layer 544. The second light transmissive layer 548 has no holes, and the reflective layer 544 can be avoided. The material diffuses into the holes, destroying the structure of the reflective layer 544, resulting in a decrease in the reflectivity of the reflective layer 544.

The electrode 56 has a first conductive layer 562 and a second conductive layer 564, wherein the first conductive layer 562 and the second conductive layer 564 are not in direct contact with each other. The first conductive layer 562 is connected to the first semiconductor layer 522 via the via 549, and the second conductive layer 564 is connected to the window layer 540 via the via 549. In another embodiment, the light-emitting element 5 further includes a first contact layer 51 between the first conductive layer 562 and the first semiconductor layer 522 to increase ohmic contact between the first conductive layer 562 and the first semiconductor layer 522; A second contact layer 53 is located between the second conductive layer 564 and the window layer 540, increasing the ohmic contact between the second conductive layer 564 and the window layer 540, reducing the operating voltage of the light-emitting element 5 to improve efficiency. The material of the first contact layer 51 and the second contact layer 53 is the same as the material of the above electrode.

Figure 6 is a schematic exploded view of a bulb, a bulb 6 having a lamp cover 61; a lens 62 disposed in the lamp cover 61; a lighting module 64 located below the lens 62; and a lamp holder 65 having a The heat dissipation slot 66 is configured to carry the lighting module 64; a connecting portion 67; and an electrical connector 68. The connecting portion 67 connects the socket 65 and the electrical connector 68. The illumination module 66 has a carrier 63; and a plurality of light-emitting elements 60 of any of the foregoing embodiments are located above the carrier 63.

7A to 7G are diagrams showing a method of manufacturing a light-emitting element according to another embodiment of the present application. Referring to FIG. 7A, the method for fabricating the light-emitting device of the present embodiment includes providing a growth substrate 701 and forming a light-emitting laminate 76 on the growth substrate 701. The light emitting laminate 76 sequentially includes a first semiconductor layer 762, an active layer 764, and a second semiconductor layer 766 on the growth substrate 701. The first semiconductor layer 762 and the second semiconductor layer 766 have different conductivity types. For example, the first semiconductor layer 762 is a p-type semiconductor layer, and the second semiconductor layer 766 is an n-type semiconductor layer. The first semiconductor layer 762, the active layer 764, and the second semiconductor layer 766 comprise a tri-five compound material, such as Al _g In _h Ga _(1-gh) P (0≦g≦1, 0≦h≦1, 0≦g +h≦1). Next, a first transparent layer 744 is formed on the light emitting laminate 76. A second transparent layer 746 may be selectively formed before the first transparent layer 744 is formed. In one embodiment, the second transparent layer 746 forms an ohmic contact with the light emitting stack 76. In another embodiment, the second transparent layer 746 increases the adhesion between the first transparent layer 744 and the light-emitting layer 76 or the ability to diffuse current. The material of the first transparent layer 744 and the second transparent layer 746 can penetrate the light emitted by the light-emitting layer 76. The material of the first transparent layer 744 and the second transparent layer 746 includes a transparent conductive material including, but not limited to, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide. (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), zinc oxide (ZnO), indium zinc oxide (IZO), indium gallium oxide (IGO) ), zinc oxide co-doped with gallium aluminum (GAZO) or a combination thereof. The material of the first transparent layer 744 and the second transparent layer 746 may further comprise gallium phosphide or diamond-like carbon (DLC). In the present embodiment, the first transparent layer 744 includes indium tin oxide (ITO), and the second transparent layer 746 includes gallium phosphide (GaP). In another embodiment, the first transparent layer 744 includes a first transparent conductive oxide, and the second transparent layer 746 includes a second transparent conductive oxide different from the first transparent conductive oxide.

Next, referring to FIG. 7B, the method further includes forming a plurality of holes 745 in the first transparent layer 744. In this embodiment, the plurality of holes 745 are formed by an etching method. The etching method includes etching along the grain boundary 745b of the first transparent layer 744, for example, using a chemical solution. The chemical solution contains a solution of an acid such as a mixture comprising oxalic acid ((COOH) ₂ · 2H ₂ O), hydrochloric acid (HCl), or sulfuric acid (H ₂ SO) and hydrofluoric acid (HF). The cross-sectional shape of the cavity 745 is substantially triangular or trapezoidal depending on the control of the etching step, such as the etching time or the composition of the etching solution. A small opening is formed around the upper side of the hole 745. In one of the cases, the width W _{3 of the} aperture 745 closer to the first portion 745w of the light emitting stack 76 is greater than the width W ₄ of the second portion 745n of the aperture 745 that is further from the light emitting stack 76. For clarity, please refer to the lower left diagram of Figure 7B, the plurality of holes 745 are in communication with each other. The first transparent layer 744 includes a plurality of protrusions 744c that are substantially separated from each other but closely arranged, and as shown in FIG. 7B, each of the protrusions 744c is surrounded by a plurality of holes 745. The plurality of holes 745 and the plurality of projections 744c form a porous structure. The shape of the projection 744c is an inverted truncated cone or an inverted pyramid. The cross-sectional shape of each of the projections 744c is substantially an inverted trapezoid. Similarly, the cross-sectional shape of the projection 744c can be adjusted by controlling the etching step such as the etching time or the composition of the etching solution. The enlarged view of the lower right side of Fig. 7B is for the purpose of clearly explaining the convex portion 744c. As shown in the cross-sectional view, the width W ₁ of the bottom base body 744cB1 of _{one of the} convex portions 744c is larger than that of the convex portion 744c. The top substrate 744cB2 has a width W ₂ of 1/3 times to maintain mechanical strength. Embodiment, when the projecting portion 744c as a truncated cone, and the cross-sectional shape comprising convex portion 744c of the width W 744cB2 trapezoidal top of the base body ₂ having a width W 744cB1 ₁ 1/3 times larger than the base body in an embodiment The total bottom area of the plurality of holes 745, that is, the total area of the bottom surface 745a of all of the plurality of holes 745 is between 50% and 90% of the area of the light-emitting stack 76. That is, the projected area of all of the plurality of apertures 745 on the light-emitting stack 76 is between 50% and 90% of the area of one surface of the light-emitting stack 76. After the etching step, the chemical solution can be rinsed away from the first transparent layer 744 using deionized water. After etching the first transparent layer 744 to form the plurality of holes 745, the method can optionally include heat treating the first transparent layer 744 to reduce the sheet resistance of the first transparent layer 744.

Next, referring to FIG. 7C, the method further includes forming a reflective layer 742 on the first transparent layer 744. Because the opening of the aperture 745 is small enough that the reflective layer 742 will not fill the aperture 745, voids will remain in the aperture 745. The reflective layer 742 comprises a metallic material such as gold, silver or aluminum. In an embodiment, the reflective layer 742 comprises a Distributed Bragg Reflector structure. The Bragg mirror structure comprises a complex Bragg mirror set, wherein each Bragg mirror set consists of a high refractive index layer and a low refractive index layer. The reflective layer 742, the first transparent layer 744, and/or the second transparent layer 746 collectively form an Omni-Directional Reflector (ODR).

Next, referring to FIG. 7D, the method further includes forming a first bonding layer 72a on the reflective layer 742. As shown in FIG. 7E, the method further includes providing a substrate 70 and forming a second bonding layer 72b on the substrate. The substrate 70 includes a conductive substrate, such as a germanium substrate. The first adhesive layer 72a and the second adhesive layer 72b include gold (Au), indium (In), tin (Sn), silver (Ag), copper (Cu), nickel (Ni), bismuth (Bi), or the like. alloy. Then, as shown in FIG. 7F, the first adhesive layer 72a and the second adhesive layer 72b are combined to form an adhesive layer 72. After the bonding, as shown in FIG. 7G, the growth substrate 701 is removed. Next, a first electrode pad 70E1 and an extension electrode 70E1' are formed on the second semiconductor layer 766. A second electrode pad 70E2 is formed on the substrate 70. The second semiconductor layer 766 can be selectively subjected to a roughening process to form a roughened surface 70R, thereby increasing light extraction efficiency. Next, a lithography process and an etch process are performed to remove the periphery of the luminescent stack 76 and expose the second transparent layer 746. A second transparent layer 746 may be over-etched. Finally, a protective layer 77 covers the roughened surface 70R and the sidewalls of the light emitting stack 76 to protect the light emitting elements from damage caused by the atmosphere. In this embodiment, the protective layer 77 also covers the plurality of sidewalls of the light-emitting stack 76 for better protection.

FIG. 7G is a schematic cross-sectional view showing the light-emitting element of the present application. The light-emitting element 7 sequentially includes a substrate 70, an adhesive layer 72, a reflective layer 742, a first transparent layer 744, a second transparent layer 746, and a light-emitting laminate 76. The light emitting stack 76 includes a first semiconductor layer 762, an active layer 764, and a second semiconductor layer 766 having a roughened surface 70R. The first electrode pad 70E1 and the extension electrode 70E1' are on the second semiconductor layer 766. The second electrode pad 70E2 is on the substrate 70. The protective layer 77 covers the roughened surface 70R and the sidewalls of the light emitting laminate 76. The first transparent layer 744 includes a protrusion 744c surrounded by a plurality of holes 745. The plurality of holes 745 and the plurality of projections 744c form a porous structure. When the light emitted by the light-emitting layer 76 reaches the first transparent layer 744, the light is reflected or scattered by the holes 745 by total reflection of the interface between the holes 745 having the voids therein and the first transparent layer 744. The light extraction efficiency of the light-emitting element 7 is increased. The detailed description of each structure of the light-emitting element 7 has been described in detail in the aforementioned FIGS. 7A to 7F.

8A to 8E are diagrams showing a method of manufacturing a light-emitting element according to another embodiment of the present application. Fig. 8F is a top view of the light emitting element. Fig. 8E is a schematic cross-sectional view showing the light-emitting element along a DD section line as shown in Fig. 8F. As shown in Fig. 8A, the method of manufacturing the light-emitting element of the present embodiment includes providing a substrate 80, such as a sapphire substrate. The method of fabricating the light emitting device further includes forming a light emitting stack 86 on the substrate 80. The light emitting stack 86 includes a semiconductor stack including a first semiconductor layer 862, an active layer 864, and a second semiconductor layer 866. The first semiconductor layer 862 and the second semiconductor layer 866 have different conductivity types. For example, the first semiconductor layer 862 is a p-type semiconductor layer, and the second semiconductor layer 866 is an n-type semiconductor layer. The first semiconductor layer 862, the active layer 864, and the second semiconductor layer 866 comprise a tri-five compound material, such as Al _x In _y Ga _(1-xy) N (0≦x≦1, 0≦y≦1, 0≦x +y≦1). Next, a lithography process and an etch process are performed to remove the first semiconductor layer 862 and the active layer 864 located in the exposed regions 86E, 86E', thereby exposing a portion of the second semiconductor layer 866. After etching, a portion of the depth of the second semiconductor layer 866 may be etched away. Next, as shown in FIG. 8B, a first dielectric layer D1 is formed substantially on the plurality of sidewalls of the light emitting stack 86. Next, a first transparent layer 844 is formed substantially on the first semiconductor layer 862. A second transparent layer 846 can be selectively formed before the first transparent layer 844 is formed. In an embodiment, the second transparent layer 846 forms an ohmic contact with the first semiconductor layer 862. In another embodiment, the second transparent layer 846 increases the adhesion between the first transparent layer 844 and the light emitting stack 86 or the ability to diffuse current. The material of the first transparent layer 844 and the second transparent layer 846 can penetrate the light emitted by the light emitting stack 86. The material of the first transparent layer 844 and the second transparent layer 846 comprises a transparent conductive material, including but not limited to indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide. (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), zinc oxide (ZnO), indium zinc oxide (IZO), indium gallium oxide (IGO) ), zinc oxide co-doped with gallium aluminum (GAZO) or a combination thereof. The material of the first transparent layer 844 and the second transparent layer 846 may also comprise gallium phosphide or diamond-like carbon (DLC). In the present embodiment, the first transparent layer 844 includes indium tin oxide (ITO), and the second transparent layer 846 includes indium zinc oxide (IZO). In another embodiment, the first transparent layer 844 includes a first transparent conductive oxide, and the second transparent layer 846 includes a second transparent conductive oxide different from the first transparent conductive oxide.

Next, referring to FIG. 8C, the method further includes forming a plurality of holes 845 in the first transparent layer 844. Similarly, the first transparent layer 844 includes a plurality of projections 844c, one of which is shown in an enlarged view in the lower right circle for clarity of illustration. The projection 844c is surrounded by a plurality of apertures 845. The detailed method of forming the holes 845 and the projections 844c and the structures of the cavities 845 and the projections 844c are substantially the same as those of the foregoing embodiments, and will not be described herein. After forming the holes 845, the first transparent layer 844 can be rinsed with deionized water. The method can optionally include heat treating the first transparent layer 844 to reduce the sheet resistance of the first transparent layer 844. Next, a reflective layer 842 is formed on the first transparent layer 844. Because the opening of the aperture 845 is small enough that the reflective layer 842 will not fill the aperture 845, voids will remain in the aperture 845. In the embodiment, the reflective layer 84 also covers the sidewalls of the first transparent layer 844 and the second transparent layer 846. The reflective layer 842 comprises a metallic material such as gold (Au), silver (Ag) or aluminum (Al). The reflective layer 842, the first transparent layer 844, and/or the second transparent layer 846 together form an Omni-Directional Reflector (ODR).

As shown in FIG. 8D, the method further includes forming a second dielectric layer D2 on the reflective layer 842, the first dielectric layer D1, and the light emitting layer 86. The second dielectric layer D2 located in the exposed regions D2E, D2E' is removed to expose the second semiconductor layer 866 and a portion of the reflective layer 842, wherein the exposed regions D2E substantially correspond to the exposed regions 86E. The method further includes forming a conductive layer M1 on the second dielectric layer D2 and the second semiconductor layer 866. The conductive layer M1 is in contact with the second semiconductor layer 866.

Next, as shown in FIG. 8E, the method further includes forming a third dielectric layer D3 on the second dielectric layer D2, the conductive layer M1, the reflective layer 842, and the second semiconductor layer 866. The third dielectric layer D3 substantially located in the bare region D2E' is removed to expose the reflective layer 842. The method further includes forming a second conductive layer on the third dielectric layer D3, the reflective layer 842, and the conductive layer M1, and then removing the second conductive layer substantially located in the region M2E to form a first electrode pad 80E1 and A second electrode pad 80E2. The first electrode pad 80E1 contacts the conductive layer M1, and the conductive layer M1 contacts the second semiconductor layer 866. In other words, the conductive layer M1 functions as an intermediate conductive material and is electrically connected to the first electrode pad 80E1 and the second semiconductor layer 866. A power supply supplies a current to the second semiconductor layer 866 via the first electrode pad 80E1 and the conductive layer M1. The second electrode pad 80E2 contacts the reflective layer 842. A power supply provides a current to the first semiconductor layer 862 via the second electrode pad 80E2, the reflective layer 842, and the first transparent layer 844.

9A to 9E illustrate a light-emitting element and a method of manufacturing the same according to another embodiment of the present application. Figure 9F shows a top view of the light emitting element. Fig. 9E is a schematic cross-sectional view showing the light-emitting element along the HIJK hatching as shown in Fig. 9F. As shown in FIG. 9A, a method of fabricating a light-emitting element includes providing a substrate 90, such as a sapphire substrate. The method of fabricating a light-emitting element further includes forming a light-emitting layer 96 on the substrate 90. The light emitting stack 96 includes a semiconductor stack including a first semiconductor layer 962, an active layer 964, and a second semiconductor layer 966. The first semiconductor layer 962 and the second semiconductor layer 966 have different conductivity types. For example, the first semiconductor layer 962 is a p-type semiconductor layer, and the second semiconductor layer 966 is an n-type semiconductor layer. The first semiconductor layer 962, the active layer 964, and the second semiconductor layer 966 comprise a tri-five compound material, such as Al _x In _y Ga _(1-xy) N (0≦x≦1, 0≦y≦1, 0≦x +y≦1). Next, a lithography process and an etch process are performed to remove the first semiconductor layer 962 and the active layer 964 located in the exposed regions 96E, 96E', thereby exposing a portion of the second semiconductor layer 966. Because the exposed regions 96E, 96E' are etched, a portion of the depth of the second semiconductor layer 966 may be etched away. Next, as shown in FIG. 9B, a current blocking layer 90CB can be selectively formed. Current blocking layer 90CB includes a dielectric material to block current flow. Next, a first transparent layer 944 is formed on the first semiconductor layer 962 and the current blocking layer 90CB. A second transparent layer 946 can be selectively formed prior to the formation of the first transparent layer 944. In an embodiment, the second transparent layer 946 forms an ohmic contact with the first semiconductor layer 962. In another embodiment, the second transparent layer 946 increases the adhesion between the first transparent layer 944 and the light-emitting layer 96 or the ability to diffuse current. The material of the first transparent layer 944 and the second transparent layer 946 can penetrate the light emitted by the light-emitting layer 96. The material of the first transparent layer 944 and the second transparent layer 946 comprises a transparent conductive material including, but not limited to, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide. (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), zinc oxide (ZnO), indium zinc oxide (IZO), indium gallium oxide (IGO) ), zinc oxide co-doped with gallium aluminum (GAZO) or a combination thereof. The material of the first transparent layer 944 and the second transparent layer 946 may also comprise gallium phosphide or diamond-like carbon (DLC). In the present embodiment, the first transparent layer 944 comprises indium tin oxide (ITO), and the second transparent layer 946 comprises indium zinc oxide (IZO). In another embodiment, the first transparent layer 944 includes a first transparent conductive oxide, and the second transparent layer 846 includes a second transparent conductive oxide different from the first transparent conductive oxide.

Next, as shown in FIG. 9C, the method further includes forming a plurality of holes 945 in the first transparent layer 944. Similarly, the first transparent layer 944 includes a plurality of projections 944c, one of which is shown in an enlarged view in the lower right circle for clarity of illustration. The projection 944c is surrounded by a plurality of holes 945. The detailed method of forming the holes 945 and the projections 944c and the structures of the cavities 945 and the projections 944c are substantially the same as those of the foregoing embodiments, and will not be described herein. It should be noted that in the present embodiment, the holes 945 are not formed in the region of the first transparent layer 944 on the current blocking layer 90CB. After forming the voids 945, the first transparent layer 944 can be rinsed with deionized water. The method can optionally include heat treating the first transparent layer 944 to reduce the sheet resistance of the first transparent layer 944. Next, the conductive layer is patterned by using a lithography process and an etching process to form intermediate conductive layers MF1, MF1E. As shown in the upper view of FIG. 9F, the intermediate conductive layer MF1E is an extended electrode extending from the intermediate conductive layer MF1 having a circular shape. At the same time, an intermediate conductive layer MF1', MF1'E is formed (MF1'E is not shown in FIG. 9C but is shown in FIG. 9F). As shown in FIG. 9F, the intermediate conductive layer MF1'E is self- An extended electrode extending in the shape of a circular intermediate conductive layer MF1'. The intermediate conductive layers MF1, MF1E are formed on the bare region 96E and on the second semiconductor layer 966. The intermediate conductive layers MF1, MF1E contact the second semiconductor layer 966. The intermediate conductive layer MF1', MF1'E is formed on the first transparent layer 944 and contacts the first transparent layer 944, wherein the intermediate conductive layer MF1 is on the current blocking layer 90CB as described above, and the intermediate conductive layer MF1'E There is no current blocking layer 90CB.

Next, as shown in FIG. 9D, the method further includes forming a reflective layer 942. Since the opening of the cavity 945 is small enough, the reflective layer 942 does not fill the cavity 945, so voids are left in the cavity 945. In the present embodiment, a Bragg reflector structure 942 is formed to cover the exposed portion of the structure, and the Bragg mirror structure 942 located in the exposed region 942E is removed by a lithography process and an etching process. The bare region 942E substantially corresponds to the position of the intermediate conductive layer MF1, MF1'. The Bragg mirror structure 942 comprises a complex Bragg mirror set, wherein each Bragg mirror set consists of a layer having a high refractive index and a layer having a low refractive index. In this embodiment, each Bragg mirror group is composed of a titanium oxide layer (Titanium Oxide, TiO _x ) and a ruthenium oxide layer (Silicon Oxide, SiO _x ).

Next, as shown in FIG. 9E, the method further includes forming a conductive layer on the Bragg mirror structure 942, and removing the conductive layer substantially located in the region M2E to form a first electrode pad 90E1 and a second electrode pad. 90E2. The first electrode pad 90E1 contacts the intermediate conductive layer MF1, and the intermediate conductive layer MF1 contacts the second semiconductor layer 966. In other words, the intermediate conductive layer MF1 serves as an intermediate conductive medium and electrically connects the first electrode pad 90E1 and the second semiconductor layer 966. In addition to this, the intermediate conductive layer MF1E serves as an extension electrode for increasing current spreading. A power supply supplies current to the second semiconductor layer 966 via the first electrode pad 90E1 and the intermediate conductive layers MF1, MF1E. The second electrode pad 90E2 contacts the intermediate conductive layer MF1', and the intermediate conductive layer MF1' contacts the first transparent layer 944. The first transparent layer 944 is electrically connected to the first semiconductor layer 962. In addition to this, as shown in Fig. 9F, the intermediate conductive layer MF1'E serves as an extension electrode for increasing current spreading. A power supply supplies current to the first semiconductor by the second electrode pad 90E2, the intermediate conductive layers MF1', MF1'E, and the first transparent layer 944 (and the second transparent layer 946, if the second transparent layer 946 is formed) Layer 962.

The above figures and descriptions respectively correspond to specific embodiments, however, the elements, embodiments, design criteria, and technical principles that are disclosed or disclosed in the various embodiments are inconsistent, contradictory, or difficult to implement together. In addition, we can arbitrarily license, exchange, match, coordinate, or merge as needed.

Although the disclosure of the present application has been described above, it is not intended to limit the scope of the application, the order of implementation, or the materials and process methods used. The various modifications and variations of the present application are not intended to be exhaustive.

1‧‧‧Lighting device
11‧‧‧LED
12‧‧‧ times carrier
13, 20, 50‧‧‧ substrates
14‧‧‧ Circuitry
15, 56‧‧‧ electrodes
16‧‧‧ solder
18‧‧‧Electrical connection structure
2, 3, 40, 5‧‧‧Lighting elements
21‧‧‧First electrode
22‧‧‧Bonded layer
23‧‧‧second electrode
24, 54‧‧‧reflective structure
241, 543‧‧ ‧ convex
242, 544‧‧‧reflective layer
243, 545‧‧ ‧ recess
244, 542‧‧‧ first light transmission layer
245, 30, 547‧‧ holes
246‧‧‧Second light transmission layer
247‧‧‧First lower surface
248, 540‧‧‧ window layer
26‧‧‧Lighting laminate
261, 541‧‧ ‧ rough upper surface
262, 522‧‧‧ first semiconductor layer
263‧‧‧ roughening the lower surface
264, 524‧‧‧ active layer
265‧‧‧flat
266, 526‧‧‧ second semiconductor layer
32‧‧‧Electrical Department
41‧‧‧shade
42‧‧‧ lens
43‧‧‧ Carrier
44‧‧‧Lighting module
45‧‧‧ lamp holder
46‧‧‧heat sink
47‧‧‧Connecting Department
48‧‧‧Electrical connector
51‧‧‧First contact layer
53‧‧‧Second contact layer
546‧‧‧First insulation
548‧‧‧The third light transmission layer
549‧‧‧ channel
562‧‧‧First conductive layer
564‧‧‧Second conductive layer
H‧‧‧height
T‧‧‧thickness
701‧‧‧ Growth substrate
90E2‧‧‧Second electrode pad
76‧‧‧Lighting laminate
762‧‧‧First semiconductor layer
764‧‧‧active layer
766‧‧‧Second semiconductor layer
744‧‧‧ first transparent layer
746‧‧‧Second transparent layer
745‧‧‧ holes
745b‧‧‧ grain boundary
745w‧‧‧Part 1
745n‧‧‧Part II
744c‧‧‧protrusion
744cB1‧‧‧ base
744cB2‧‧‧ top base
745a‧‧‧ bottom surface
742‧‧‧reflective layer
72a‧‧‧First bonding layer
70‧‧‧Substrate
72b‧‧‧Second bonding layer
72‧‧‧Adhesive layer
70E1‧‧‧First electrode pad
70E1'‧‧‧Extended electrode
70E2‧‧‧Second electrode pad
70R‧‧‧ roughened surface
77‧‧‧Protective layer
80‧‧‧Substrate
86‧‧‧Lighting laminate
862‧‧‧First semiconductor layer
864‧‧‧active layer
866‧‧‧Second semiconductor layer
86E, 86E'‧‧‧ bare areas
D1‧‧‧First dielectric layer
844‧‧‧ first transparent layer
846‧‧‧Second transparent layer
845‧‧‧ holes
844c‧‧‧protrusion
842‧‧‧reflective layer
D2‧‧‧Second dielectric layer
D2E, D2E'‧‧‧ bare areas
M1‧‧‧ conductive layer
D3‧‧‧ third dielectric layer
M2E‧‧‧ area
80E1‧‧‧First electrode pad
80E2‧‧‧Second electrode pad
90‧‧‧Substrate
96‧‧‧Lighting laminate
962‧‧‧First semiconductor layer
964‧‧‧active layer
966‧‧‧Second semiconductor layer
96E, 96E'‧‧‧ exposed areas
90CB‧‧‧current blocking layer
944‧‧‧First transparent layer
946‧‧‧Second transparent layer
945‧‧ hole
944c‧‧‧protrusion
MF1, MF1E‧‧‧ intermediate conductive layer
MF1', MF1'E‧‧‧ intermediate conductive layer
96E‧‧‧naked area
942‧‧‧reflective layer
942‧‧‧ Bragg mirror structure
942E‧‧‧naked area
M2E‧‧‧ area
90E1‧‧‧First electrode pad
W ₁ , W ₂ , W ₃ , W ₄ ‧ ‧ width

Figure 1 is a schematic view showing the structure of a conventional light-emitting device;

2 is a cross-sectional view showing a light-emitting element according to an embodiment of the present application;

3 is a cross-sectional view showing a light-emitting element according to another embodiment of the present application;

4 is a schematic view showing a material deposition direction of a second light transmissive layer in the embodiment of FIG. 3;

FIG. 5 is a cross-sectional view showing a light-emitting element according to another embodiment of the present application;

Figure 6 is a schematic exploded view of a light bulb according to an embodiment of the present application;

7A to 7G are diagrams showing a method of manufacturing a light-emitting element according to another embodiment of the present application;

8A to 8E are diagrams showing a method of manufacturing a light-emitting element according to another embodiment of the present application, and FIG. 8E is a cross-sectional view showing a light-emitting element along a DD section line as shown in FIG. 8F;

8F is a top view of the light emitting element;

9A to 9E are diagrams showing a light-emitting element and a method of manufacturing the same according to another embodiment of the present application, and FIG. 9E is a cross-sectional view showing the light-emitting element along a HIJK hatching as shown in FIG. 9F;

Figure 9F shows a top view of the light emitting element.

no.

70‧‧‧Substrate

70E2‧‧‧Second electrode pad

72‧‧‧Adhesive layer

742‧‧‧reflective layer

745‧‧‧ holes

745a‧‧‧ bottom surface

744‧‧‧ first transparent layer

744c‧‧‧protrusion

746‧‧‧Second transparent layer

762‧‧‧First semiconductor layer

764‧‧‧active layer

766‧‧‧Second semiconductor layer

76‧‧‧Lighting laminate

77‧‧‧Protective layer

70E1'‧‧‧Extended electrode

70E1‧‧‧First electrode pad

Claims (10)

a light-emitting element comprising: a reflective layer; a first transparent layer on the reflective layer, comprising a protrusion; a light-emitting layer on the first transparent layer and comprising an active layer; A cavity is located in the first transparent layer, wherein the projection is surrounded by the plurality of holes. The illuminating element according to claim 1, wherein the bulging portion has a substantially trapezoidal cross-sectional shape. The illuminating element of claim 2, wherein the protrusion comprises a base body and a top substrate on the base body, the base body having a width greater than 1/3 times a width of the top substrate. The illuminating element of claim 1, wherein one of the holes has a substantially triangular or trapezoidal cross-sectional shape. The illuminating element of claim 4, wherein the holes have a first portion and a second portion that is further from the illuminating laminate than the first portion, the first portion having a width greater than a width of the second portion. The light-emitting element of claim 1, further comprising a second transparent layer between the first transparent layer and the light-emitting layer. The illuminating element of claim 1, wherein the protrusion has an inverted truncated cone or an inverted pyramid. A method of fabricating a light-emitting device, comprising the steps of: providing a light-emitting stack comprising a second semiconductor layer, an active layer on the second semiconductor layer, and a first semiconductor layer on the active layer; Forming a first transparent layer on the first semiconductor layer; and etching the first transparent layer to form a plurality of holes and a protrusion surrounded by the plurality of holes. The method of manufacturing a light-emitting element according to claim 8, after the etching the first transparent layer, further comprising heat-treating the first transparent layer. The method of manufacturing a light-emitting device according to claim 8, further comprising etching a portion of the first semiconductor layer and a portion of the active layer to expose a portion of the second semiconductor layer before forming the first transparent layer.