TWI701847B - Light-emitting element having a reflective structure with high efficiency - Google Patents

Abstract

A light-emitting element comprises a substrate; a light-emitting stack on the substrate; a transparent layer between the light-emitting stack and the substrate; and a plurality of cavities between the substrate and the light-emitting stack; wherein from a cross section view of the light-emitting element, the transparent layer comprises a first width, and the light-emitting stack comprises a second width smaller than the first width.

Description

Light-emitting element with high-efficiency reflective structure

The present invention relates to a light-emitting element, in particular to a light-emitting element with a highly efficient reflective structure.

Optoelectronic components, such as light-emitting diodes (LEDs), are currently widely used in optical display devices, traffic signs, data storage devices, communication devices, lighting devices, and medical equipment. In addition, the above-mentioned LED can be combined with other components to form a light emitting device. Figure 1 is a schematic diagram of the structure of a conventional light emitting device. As shown in Figure 1, a light emitting device 1 includes a submount 12 with a circuit 14; a solder 16 (solder) is located on the submount 12, and As a result, the solder 16 fixes the LED 11 on the secondary carrier 12 and electrically connects the LED 11 with the circuit 14 on the secondary carrier 12; and an electrical connection structure 18 to electrically connect the electrode 15 of the LED 11 and the secondary carrier 12 The above circuit 14; wherein, the above-mentioned secondary carrier 12 can be a lead frame or a large-size mounting substrate (mounting substrate).

The present application provides a light-emitting element, which includes: a substrate; a light-emitting stack on the substrate; a transparent layer between the substrate and the light-emitting stack; and a plurality of holes located on the substrate and the substrate Between the light-emitting stacks; where viewed from the cross-section of the light-emitting element, the transparent layer has a first width, and the light-emitting stack has a second width smaller than the first width.

In the light-emitting element of the present application, the light-emitting stack exposes the transparent layer.

1: Light-emitting device

11: LED

12: Secondary carrier

13, 20, 50: substrate

14: Circuit

15, 56: Electrode

16: Solder

18: Electrical connection structure

2, 3, 40, 5: light-emitting element

21: First electrode

22: Adhesive layer

23: second electrode

24, 54: reflective structure

241, 543: convex

242, 544: reflective layer

243, 545: recess

244, 542: the first transparent layer

245, 30, 547: holes

246: second light transmission layer

247: The first lower surface

248, 540: Window layer

26: luminous stack

261, 541: Roughen the upper surface

262, 522: first semiconductor layer

263: Roughen the bottom surface

264, 524: Active layer

265: flat part

266, 526: second semiconductor layer

32: conductive part

41: Lampshade

42: lens

43: carrier

44: lighting module

45: lamp holder

46: heat sink

47: Connection

48: electric connector

51: first contact layer

53: second contact layer

546: first insulating layer

548: third transparent layer

549: Channel

562: first conductive layer

564: second conductive layer

h: height

t: thickness

701: growth substrate

90E2: second electrode pad

76: luminous stack

762: first semiconductor layer

764: active layer

766: second semiconductor layer

744: first transparent layer

746: second transparent layer

745: hole

745b: Grain boundary

745w: Part One

745n: part two

744c: protrusion

744cB1: Substrate

744cB2: Top substrate

745a: bottom surface

742: reflective layer

72a: First bonding layer

70: substrate

72b: second adhesive layer

72: Adhesive layer

70E1: the first electrode pad

70E1’: Extension electrode

70E2: second electrode pad

70R: roughened surface

77: protective layer

80: substrate

86: luminous stack

862: first semiconductor layer

864: active layer

866: second semiconductor layer

86E, 86E’: naked area

D1: The first dielectric layer

844: first transparent layer

846: second transparent layer

845: hole

844c: protrusion

842: reflective layer

D2: second dielectric layer

D2E, D2E’: naked area

M1: conductive layer

D3: The third dielectric layer

M2E: area

80E1: the first electrode pad

80E2: second electrode pad

90: substrate

96: luminous stack

962: first semiconductor layer

964: active layer

966: second semiconductor layer

96E, 96E’: naked area

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: bare area

942: reflective layer

942: Bragg reflector structure

942E: exposed area

M2E: area

90E1: first electrode pad

W ₁ , W ₂ , W ₃ , W ₄ : width

Fig. 1 is a schematic diagram of the structure of a conventional light-emitting device; Fig. 2 is a schematic cross-sectional view of a light-emitting element according to an embodiment of the present application; Fig. 3 is a schematic cross-sectional view of a light-emitting element according to another embodiment of the present application; Fig. 3 is a schematic diagram of the material deposition direction of the second light-transmitting layer in the embodiment of Fig. 3; Fig. 5 is a cross-sectional schematic diagram of a light-emitting element of another embodiment of the application; Fig. 6 is an embodiment of the application Fig. 7A to Fig. 7G are a method of manufacturing a light-emitting device according to another embodiment of the application; Figs. 8A to 8E are a method of manufacturing a light-emitting device according to another embodiment of the application, Fig. 8E A schematic cross-sectional view of the light-emitting element along the DD section line as shown in Figure 8F is shown; Figure 8F is a top view of the light-emitting element; Figures 9A to 9E show a light-emitting device and its manufacturing method according to another embodiment of the present application. Figure 9E shows a schematic cross-sectional view of the light-emitting device along the HIJK section line as shown in Figure 9F; and Figure 9F The figure shows the top view of the light-emitting element.

In order to make the above-mentioned features and advantages of the present application more obvious and understandable, the following specific examples are given in conjunction with the accompanying drawings to describe in detail as follows. In the drawings or descriptions, similar or identical parts use the same reference numerals, and in the drawings, the shape or thickness of the components can be enlarged or reduced. It should be noted that the components not shown or described in the figure may be in the form known to those who are familiar with the art.

Figure 2 is a cross-sectional view of a light-emitting device according to an embodiment of the application. As shown in Figure 2, a light-emitting element 2 has a substrate 20; an adhesive layer 22 located on the substrate 20; a reflective structure 24 located on the adhesive layer 22; a light-emitting stack 26 located on the reflective structure 24 On; a first electrode 21, located under the substrate 20; and a second electrode 23, located on the light-emitting stack 26. The light-emitting stack 26 has a first semiconductor layer 262 on the reflective structure 24; an active layer 264 on the first semiconductor layer 262; and a second semiconductor layer 266 on the active layer 264.

The first electrode 21 and/or the second electrode 23 are used to receive an external voltage, and may be made 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 alloys of the above materials.

The light-emitting laminate 26 has a roughened upper surface 261 and a roughened lower surface 263, which can reduce the probability of total reflection and improve the light extraction efficiency. The roughened upper surface has a flat portion 265, and the second electrode 23 can be located on the flat portion 265, which improves the adhesion between the second electrode 23 and the light-emitting stack 26, and reduces the subsequent processing of the second electrode 23, such as wire bonding. And the probability of peeling off from the light-emitting laminate 26. The material of the light-emitting stack 26 can be a semiconductor material, containing more than one element, and this element can be selected from gallium (Ga), aluminum (Al), indium (In), phosphorus (P), nitrogen (N), zinc (Zn) ), cadmium (Cd) and selenium (Se). The electrical properties of the first semiconductor layer 262 and the second semiconductor layer 266 are different, and are used to generate electrons or holes. The active layer 124 can emit one or more color lights, which can be visible or invisible light, and its structure can be 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 transparent layer 244 and a window layer 248 from the bonding layer 22 to the light-emitting stack 26. The window layer 248 has a roughened lower surface, and the roughened lower surface has a plurality of convex portions 241 and concave portions 243. Wherein, the roughened lower surface further has a flat portion located directly under the second electrode 23 for forming an ohmic contact with the first transparent layer 244. At least one hole 245 is formed in the first light-transmitting layer 244, and the hole 245 can extend from the roughened lower surface of the window layer 248 down to the reflective layer 242. In another embodiment, the hole 245 may extend downward from the convex portion 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 transparent layer 244. Since the refractive index of the hole 245 is smaller than the window layer 248 and the first light transmission The refractive index of the 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-transmitting layer 244, so the light emitted by the light-emitting laminate 26 is directed to the hole 245 , The probability of forming total reflection at the interface between the window layer 248 and the hole 245 increases. In addition, the light that enters the first light-transmitting layer 244 without forming total reflection at the interface between the window layer 248 and the first light-transmitting layer 244 will also form total reflection at the interface between the first light-transmitting layer 244 and the hole 245. Therefore, the light extraction efficiency of the light emitting element 2 is improved. The hole 245 can be viewed as a funnel with a wide top and a narrow bottom. The reflective structure 24 may further include a second light-transmitting layer 246. The second light-transmitting layer 246 is located between a portion of the first light-transmitting layer 244 and the window layer 248 to increase the gap between the first light-transmitting layer 244 and the window layer 248. Ohmic contact. In another embodiment, the second light-transmitting layer 246 may have a hole 245, wherein the refractive index of the hole 245 is smaller than the refractive index of the window layer 248 and the second light-transmitting layer 246. Since the refractive index of the hole 245 is smaller than the refractive index of the window layer 248 and the second transparent layer 246, the critical angle of the interface between the second transparent layer 246 and the hole 245 is smaller than the interface between the window layer 248 and the second transparent layer 246 Therefore, after the light emitted by the light-emitting stack 26 is directed to the hole 245, the probability of forming a total reflection at the interface between the second light-transmitting layer 246 and the hole 245 increases. In another embodiment, the reflective structure 24 may not have the window layer 248 and the first light-transmitting layer 244 is formed under the light-emitting stack 26. At this time, the roughened lower surface 263 of the light-emitting stack 26 has a plurality of protrusions and recesses, which facilitate the formation of the holes 245.

The window layer 248 is transparent to the light emitted by the light-emitting stack 26 to improve the efficiency of light extraction. The material can 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), oxide Indium Cerium (ICO), Indium tungsten oxide (IWO), indium titanium oxide (ITiO), indium zinc oxide (IZO), indium gallium oxide (IGO), gallium aluminum zinc oxide (GAZO) or a combination of the above materials. 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-transmitting layer 244 and/or the second light-transmitting layer 246 is transparent to the light emitted by the light-emitting laminate 26, so as to increase the ohmic contact between the window layer 248 and the reflective layer 242, as well as current conduction and diffusion, and The reflective layer 242 forms an Omni-Directional Reflector (ODR). The material can 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 zinc oxide (AZO) ), zinc tin oxide (ZTO), gallium zinc oxide (GZO), zinc oxide (ZnO), gallium phosphide (GaP), indium cerium oxide (ICO), indium tungsten oxide (IWO), indium titanium oxide (ITiO), Indium zinc oxide (IZO), indium gallium oxide (IGO), gallium aluminum zinc oxide (GAZO) or a combination of the above materials. The material of the first transparent 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 of the above materials . The method of forming the first light-transmitting layer 244 and/or the second light-transmitting layer 246 includes physical vapor deposition, such as electron beam evaporation or sputtering. The reflective layer 242 can reflect the light from the light emitting stack 26, and its material 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 alloys of the above materials.

The bonding layer 22 can connect the substrate 20 and the reflective structure 24, and can have a plurality of subordinate layers (not shown). The material of the bonding layer 22 can be a transparent conductive material or a metal material. The transparent conductive material includes 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), gallium phosphide (GaP), indium cerium oxide (ICO), indium tungsten oxide (IWO), indium titanium oxide (ITiO), indium zinc oxide (IZO), indium gallium oxide (IGO), gallium oxide Aluminum zinc (GAZO) or a combination of the above materials. 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 alloys of the above materials, etc.

The substrate 20 can be used to support the light-emitting stack 26 and other layers or structures on it, and its material can be a transparent material or a conductive material. Transparent materials include but are not limited to Sapphire, Diamond, Glass, Epoxy, Quartz, Acrylic, Alumina (Al ₂ O ₃ ), Oxidation Zinc (ZnO) or aluminum nitride (AlN), etc. 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), Silicon (Si), Phosphating Iodine (IP), zinc selenide (ZnSe), gallium arsenide (GaAs), silicon carbide (SiC), gallium phosphide (GaP), gallium arsenide phosphorus (GaAsP), zinc selenide (ZnSe), indium phosphide (InP), lithium gallate (LiGaO ₂ ), or lithium aluminate (LiAlO ₂ ).

FIG. 3 is a cross-sectional view of a light-emitting device according to another embodiment of the application. A light-emitting element 3 has a structure similar to the above-mentioned light-emitting element 2, but the second transparent layer 246 of the reflective structure 24 has a plurality of holes 30, so that the refractive index of the second transparent layer 246 is less than 1.4, preferably 1.35. As shown in FIG. 4, the formation of the hole 30 is to fix the wafer 4, and deposit the second light-transmitting layer 246 by the physical vapor method in a specific direction, for example, the direction D perpendicular to the normal line of the wafer. The material is on the wafer. Because of the adjustment of the deposition direction D, the material cannot be deposited in a part of the area, and the hole 30 is formed. Among them, the included angle θ is about 60 degrees. Refraction of the second transparent layer 246 formed with holes 30 The refractive index is lower than that of the light-transmitting layer without holes, which can increase the probability of total reflection between the second light-transmitting layer 246 and the interface of other layers, and improve the light-emitting efficiency of the light-emitting element 3. The first light-transmitting layer 244 can be formed under the second light-transmitting layer 246 by a physical vapor method or a chemical vapor method, and its thickness is greater than that of the second light-transmitting layer 246, which can prevent the material of the reflective layer 242 from spreading to the second Transparent layer 246. The first light-transmitting layer 244 does not have holes, which can prevent the material of the reflective layer 242 from being diffused into the holes, damaging the structure of the reflective layer 242, and reducing the reflectivity of the reflective layer 242. The first light-transmitting layer 244 has a first lower surface 247, and the first lower surface 247 can be polished by a chemical mechanical polishing (CMP) method so that the centerline average roughness (Ra) is about 1 nm-40 nm. When the reflective layer 242 is formed under the first lower surface 247, the reflective layer 242 can form a surface with a relatively low 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 located between the light-emitting stack 26 and the reflective layer 242. In another embodiment, the conductive portion 32 may be located between the window layer 248 and the reflective layer 242. The conductive portion 32 is used to conduct current, and its material can be a transparent conductive material or a metal material. 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 cerium oxide (ICO), Indium tungsten oxide (IWO), indium titanium oxide (ITiO), indium zinc oxide (IZO), indium gallium oxide (IGO), gallium aluminum zinc oxide (GAZO) or a combination of the above materials. 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 alloys of the above materials.

In this embodiment, the material of the first light-transmitting layer 244 and/or the second light-transmitting layer 246 may be an insulating material, such as polyimide (PI), benzocyclobutene (BCB), or perfluorocyclobutene. Alkyl (PFCB), Magnesium Oxide (MgO), Su8, Epoxy, Acrylic Resin, Cycloolefin Polymer (COC), Polymethyl Methacrylate (PMMA), Polyterephthalic Acid Ethylene Diester (PET), Polycarbonate (PC), Polyetherimide, Fluorocarbon Polymer, Glass, Alumina (Al ₂ O ₃ ), Silicon Oxide (SiO _x ), titanium oxide (TiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), silicon nitride (SiN _x ), magnesium fluoride (MgF ₂ ), spin-on glass (SOG) or tetraethoxysilane (TEOS) .

Fig. 5 is a cross-sectional view of a light-emitting device according to another embodiment of the application. As shown in FIG. 5, a light-emitting element 5 has a substrate 50; a light-emitting stack 52 on the substrate 50; a reflective structure 54 on the light-emitting stack 52; and an electrode 56 on the reflective structure 54 Above. The light-emitting stack 52 has a first semiconductor layer 522 located on the substrate 50; an active layer 524 located on the first semiconductor layer 522; and a second semiconductor layer 526 located on the active layer 524, part of which is 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 stack 52; a first transparent layer 542 on the window layer 540; a reflective layer 544 on the first transparent layer 542; and a An insulating layer 546 is located on the reflective layer 544. The window layer 540 has a roughened upper surface 541, and the roughened upper surface has a plurality of convex portions 543 and concave portions 545. At least one hole 547 is formed in the first transparent layer 542 and is located on 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 transparent layer 542. In another embodiment, the hole 547 may extend upward from the recess 545. Since the refractive index of the hole 547 is smaller than that of the window layer 540 and The refractive index of the first transparent layer 542, the critical angle of the interface between the window layer 540 and the hole 547 is smaller than the critical angle of the interface between the window layer 540 and the first transparent layer 542, so the light emitted by the light-emitting laminate 52 After shooting toward the hole 547, the probability of forming a total reflection at the interface between the window layer 540 and the hole 547 increases. In addition, the light entering the first light-transmitting layer 542 without being totally reflected at the interface between the window layer 540 and the first light-transmitting layer 542 will also form total reflection at the interface between the first light-transmitting layer 542 and the hole 547. Therefore, the light-emitting efficiency of the light-emitting element 5 is improved, and the hole 547 can be in the shape of an inverted funnel with a width at the bottom and a narrow at the top. Because the light emitted from the light-emitting stack 52 has an increased probability of forming total reflection at the interface between the window layer 540 and the hole 547 and the interface between the first light-transmitting layer 542 and the hole 547, the probability of the light reaching the electrode 56 being reduced by the electrode 56 is reduced. The probability of absorption improves the luminous efficiency of the light-emitting element 5. The first insulating layer 546 can cover the reflective layer 544 so that the reflective layer 544 does not directly contact the electrode 56 to prevent the material of the reflective layer 544 from spreading to the electrode 56 and reduce the reflectivity of the reflective layer 544. The reflective structure 54 further includes a plurality of channels 549 formed in the first transparent layer 542 and the first insulating layer 546, and the electrode 56 can be electrically connected to the light emitting stack 52 through the channels 549. The reflective structure 54 may further include a second light-transmitting layer 548. The second light-transmitting layer 548 is located between a portion of the first light-transmitting layer 542 and the reflective layer 544. The second light-transmitting layer 548 has no holes, which can avoid the reflective layer 544. The material diffuses into the holes, destroys the structure of the reflective layer 544, and causes the reflectivity of the reflective layer 544 to decrease.

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 do not directly contact each other. The first conductive layer 562 is connected to the first semiconductor layer 522 via a channel 549, and the second conductive layer 564 is connected to the window layer 540 via a channel 549. In another embodiment, the light-emitting element 5 further includes a first contact layer 51 located on the first Between the conductive layer 562 and the first semiconductor layer 522, the ohmic contact between the first conductive layer 562 and the first semiconductor layer 522 is increased; 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 reduces the operating voltage of the light-emitting element 5 to improve efficiency. Among them, the materials of the first contact layer 51 and the second contact layer 53 are the same as the material of the aforementioned electrode.

Figure 6 is an exploded schematic diagram of a light bulb. A light bulb 6 has a lamp shade 61; a lens 62 is placed in the lamp shade 61; an illumination module 64 is located under the lens 62; and a lamp holder 65 has a The heat dissipation slot 66 is used to carry the lighting module 64; a connecting portion 67; and an electrical connector 68, wherein the connecting portion 67 connects the lamp holder 65 and the electrical connector 68. The lighting module 66 has a carrier 63; and a plurality of light-emitting elements 60 of any of the foregoing embodiments are located on the carrier 63.

Figures 7A to 7G show a method of manufacturing a light-emitting device according to another embodiment of the application. Please refer to FIG. 7A. The manufacturing method of the light-emitting element of this embodiment includes providing a growth substrate 701 and forming a light-emitting stack 76 on the growth substrate 701. The light-emitting stack 76 includes a first semiconductor layer 762, an active layer 764, and a second semiconductor layer 766 on the growth substrate 701 in sequence. 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 include three or five group compound materials, 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 stack 76. Before the first transparent layer 744 is formed, a second transparent layer 746 may be selectively 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 stack 76 or the ability of current diffusion. The materials of the first transparent layer 744 and the second transparent layer 746 can allow the light emitted by the light-emitting stack 76 to penetrate. The material of the first transparent layer 744 and the second transparent layer 746 includes a transparent conductive material. 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), indium zinc oxide (IZO), indium gallium oxide (IGO) ), zinc oxide co-doped gallium aluminum (GAZO) or a combination thereof. The materials of the first transparent layer 744 and the second transparent layer 746 may also include gallium phosphide or diamond-like carbon (DLC). In this 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, for example, etching along the grain interface 745b of the first transparent layer 744 using a chemical solution. Chemical solution comprises a solution of an acid, such as oxalic acid containing _{((COOH) 2 .2H 2 O} ), hydrochloric acid (HCI), or sulfuric acid (H ₂ SO) and hydrofluoric acid (HF) is mixed. According to the control of the etching step, such as the etching time or the composition of the etching solution, the cross-sectional shape of the cavity 745 is substantially triangular or trapezoidal. A small opening is formed around the upper part of the hole 745. In one case, the width W ₃ of the first portion 745w of the hole 745 closer to the light-emitting stack 76 is larger than the width W ₄ of the second portion 745n of the hole 745 farther from the light-emitting stack 76. For clarity, please refer to the lower left diagram of Figure 7B, the plurality of holes 745 are connected to 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 protrusion 744c is surrounded by a plurality of holes 745. The plurality of holes 745 and the plurality of protrusions 744c form a porous structure. The shape of the protrusion 744c is an inverted truncated cone or an inverted pyramid. The cross-sectional shape of each protrusion 744c is substantially an inverted trapezoid. Similarly, the cross-sectional shape of the protrusion 744c can be adjusted by controlling the etching step, such as the etching time or the composition of the etching solution. The enlarged view at the bottom right of Figure 7B is to clearly illustrate the protrusion 744c. As shown in the cross-sectional view, the width W ₁ of the base body 744cB1 of _{one of the} protrusions 744c is greater than that of the protrusion 744c. The width W ₂ of the top substrate 744cB2 is 1/3 times to maintain the mechanical strength. In one embodiment, when the protruding portion 744c is a truncated cone, and the cross-sectional shape of the protruding portion 744c includes a trapezoid with a width W _{1 of the} bottom substrate 744cB1 greater than 1/3 times the width W ₂ of the top substrate 744cB2 , The total bottom area of the plurality of holes 745, that is, the total area of the bottom surface 745a of all the plurality of holes 745 is between 50% and 90% of the area of the light emitting stack 76. In other words, the projected area of all the plurality of holes 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, deionized water may be used to rinse the chemical solution from the first transparent layer 744. After the first transparent layer 744 is etched to form a plurality of holes 745, the method may 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 hole 745 is small enough, the reflective layer 742 will not fill the hole 745, so there will be a gap in the hole 745. The reflective layer 742 includes a metal material, such as gold, silver, or aluminum. In one embodiment, the reflective layer 742 includes a Bragg reflector (Distributed Bragg Reflector) structure. The Bragg reflector structure includes a plurality of Bragg reflector groups, wherein each Bragg reflector group is composed 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 together 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 silicon substrate. The first bonding layer 72a and the second bonding 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. A roughening process can be selectively performed on the second semiconductor layer 766 to form a roughened surface 70R, thereby increasing the light extraction efficiency. Then, a lithography process and an etching process are performed to remove the periphery of the light-emitting stack 76 and expose the second transparent layer 746. The second transparent layer 746 may be slightly 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 element from damage caused by the atmosphere. In this embodiment, for better protection, the protective layer 77 also covers the multiple sidewalls of the light-emitting stack 76.

Fig. 7G shows a schematic cross-sectional view of the light-emitting device of the present application. The light-emitting element 7 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 stack 76 in this order. 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 stack 76. The first transparent layer 744 includes a protrusion 744 c surrounded by a plurality of holes 745. The plurality of holes 745 and the plurality of protrusions 744c form a porous structure. When the light emitted by the light-emitting stack 76 reaches the first transparent layer 744, the light will be reflected or scattered by the holes 745 by the total reflection of the interface between the holes 745 with voids therein and the first transparent layer 744, thus 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.

Figures 8A to 8E are a method of manufacturing a light-emitting device according to another embodiment of the application. Figure 8F shows a top view of the light-emitting element. FIG. 8E shows a schematic cross-sectional view of the light-emitting device along the DD section line as shown in FIG. 8F. As shown in FIG. 8A, the manufacturing method of the light-emitting element of this embodiment includes providing a substrate 80, such as a sapphire substrate. The manufacturing method of 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, which sequentially includes 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 include three or five group compound materials, such as Al _x In _y Ga _(1-xy) N(0≦x≦1, 0≦y≦1, 0≦x +y≦1). Then, a lithography process and an etching 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 partial depth of the second semiconductor layer 866 may be etched away. Next, as shown in FIG. 8B, a first dielectric layer D1 is substantially formed 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. Before the first transparent layer 844 is formed, a second transparent layer 846 may be selectively formed. In one embodiment, the second transparent layer 846 and the first semiconductor layer 862 form an ohmic contact. 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 of current spreading. The materials of the first transparent layer 844 and the second transparent layer 846 can allow the light emitted by the light-emitting stack 86 to pass through. The material of the first transparent layer 844 and the second transparent layer 846 includes a transparent conductive material. 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), indium zinc oxide (IZO), indium gallium oxide (IGO) ), zinc oxide co-doped gallium aluminum (GAZO) or a combination thereof. The materials of the first transparent layer 844 and the second transparent layer 846 may further include gallium phosphide or diamond-like carbon (DLC). In this 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 protrusions 844c. For clarity of description, one of the protrusions 844c is shown in the enlarged view in the lower right circle. The protrusion 844c is surrounded by a plurality of holes 845. The detailed method of forming the hole 845 and the protrusion 844c and the structure of the hole 845 and the protrusion 844c are substantially the same as the content of the foregoing embodiment, and will not be repeated here. After the holes 845 are formed, the first transparent layer 844 can be rinsed with deionized water. This method It may 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 hole 845 is small enough, the reflective layer 842 will not fill the hole 845, so there will be a gap in the hole 845. In this 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 includes a metal 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 stack 86. The second dielectric layer D2 located in the exposed areas D2E, D2E' is removed to expose the second semiconductor layer 866 and part of the reflective layer 842, wherein the exposed area D2E substantially corresponds to the exposed area 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 exposed area 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 serves as an intermediate conductive material and is electrically connected to the first electrode pad 80E1 and the second semiconductor layer 866. A power supply with the first The electrode pad 80E1 and the conductive layer M1 provide a current to the second semiconductor layer 866. The second electrode pad 80E2 contacts the reflective layer 842. A power supply provides a current to the first semiconductor layer 862 through the second electrode pad 80E2, the reflective layer 842 and the first transparent layer 844.

FIGS. 9A to 9E show a light-emitting device and its manufacturing method according to another embodiment of the present application. Figure 9F shows a top view of the light-emitting element. FIG. 9E shows a schematic cross-sectional view of the light-emitting device along the HIJK section line as shown in FIG. 9F. As shown in FIG. 9A, the method of manufacturing a light-emitting device includes providing a substrate 90, such as a sapphire substrate. The method of manufacturing the light-emitting device further includes forming a light-emitting stack 96 on the substrate 90. The light emitting stack 96 includes a semiconductor stack, which sequentially includes 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 include a three-five group compound material, such as Al _x In _y Ga _(1-xy) N(0≦x≦1, 0≦y≦1, 0≦x +y≦1). Then, a photolithography process and an etching process are performed to remove the first semiconductor layer 962 and the active layer 964 in the exposed regions 96E and 96E′, thereby exposing a portion of the second semiconductor layer 966. Because the exposed regions 96E and 96E' are etched, a partial 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. The 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. Before the first transparent layer 944 is formed, a second transparent layer 946 may be selectively formed. In one embodiment, the second transparent layer 946 and the first semiconductor layer 962 form an ohmic contact. In another embodiment, the second transparent layer 946 increases the adhesion between the first transparent layer 944 and the light-emitting stack 96 or the ability of current diffusion. The materials of the first transparent layer 944 and the second transparent layer 946 can allow the light emitted by the light-emitting stack 96 to pass through. The material of the first transparent layer 944 and the second transparent layer 946 includes a transparent conductive material. 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), indium zinc oxide (IZO), indium gallium oxide (IGO) ), zinc oxide co-doped gallium aluminum (GAZO) or a combination thereof. The materials of the first transparent layer 944 and the second transparent layer 946 may also include gallium phosphide or diamond-like carbon (DLC). In this embodiment, the first transparent layer 944 includes indium tin oxide (ITO), and the second transparent layer 946 includes 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 protrusions 944c. For clear description, one of the protrusions 944c is shown in the enlarged view in the lower right circle. The protrusion 944c is surrounded by a plurality of holes 945. The detailed method for forming the cavity 945 and the protrusion 944c and the structure of the cavity 945 and the protrusion 944c are substantially the same as the content of the foregoing embodiment, and will not be repeated here. It is worth noting that, in this embodiment, the hole 945 is not formed in the region of the first transparent layer 944 on the current blocking layer 90CB. After the holes 945 are formed, the first transparent layer 944 can be rinsed with deionized water. The method may optionally include heat-treating the first transparent layer 944 to reduce the sheet resistance of the first transparent layer 944. Then, the conductive layer is patterned by using a photolithography process and an etching process to form the intermediate conductive layers MF1 and MF1E. Such as 9F As shown in the top view of the figure, the intermediate conductive layer MF1E is an extension electrode extending from the intermediate conductive layer MF1 having a circular shape. Form an intermediate conductive layer MF1' and MF1'E at the same time (MF1'E is not shown in Figure 9C but shown in Figure 9F). As shown in Figure 9F, the intermediate conductive layer MF1'E is self-contained An extension electrode extending from the intermediate conductive layer MF1' in a circular shape. The intermediate conductive layers MF1 and MF1E are formed on the exposed area 96E and on the second semiconductor layer 966. The intermediate conductive layers MF1, MF1E contact the second semiconductor layer 966. The intermediate conductive layers MF1', MF1'E are formed on the first transparent layer 944 and contact the first transparent layer 944, wherein the intermediate conductive layer MF1 is located on the current blocking layer 90CB as described above, and the intermediate conductive layer MF1'E There is no current blocking layer 90CB underneath.

Next, as shown in FIG. 9D, the method further includes forming a reflective layer 942. Because the opening of the hole 945 is small enough, the reflective layer 942 will not fill the hole 945, so there will be a gap in the hole 945. In this embodiment, a Distributed Bragg Reflector structure 942 is formed to cover the exposed part of the aforementioned structure, and the Bragg reflector structure 942 in the exposed area 942E is removed by a photolithography process and an etching process. The bare area 942E substantially corresponds to the position of the middle conductive layer MF1, MF1'. The Bragg mirror structure 942 includes a plurality of Bragg mirror groups, where each Bragg mirror group is composed of a layer with a high refractive index and a layer with a low refractive index. In this embodiment, each Bragg reflector group is composed of a titanium oxide layer (TiO _x ) and a silicon 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 middle conductive layer MF1, 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, the middle conductive layer MF1E serves as an extension electrode to increase current diffusion. A power supply provides current to the second semiconductor layer 966 through the first electrode pad 90E1 and the intermediate conductive layers MF1 and 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, as shown in Fig. 9F, the intermediate conductive layer MF1'E serves as an extension electrode for increasing current diffusion. A power supply provides current to the first semiconductor through 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 a second transparent layer 946 is formed) Layer 962.

Although the above drawings and descriptions only correspond to specific embodiments respectively, however, the elements, implementations, design criteria, and technical principles described or disclosed in the various embodiments are in conflict, contradictory, or difficult to implement together. In addition, we can refer to, exchange, match, coordinate, or merge as needed.

Although the content disclosed in this application has been described above, it is not intended to limit the scope of this application, the order of implementation, or the materials and manufacturing methods used. Various modifications and changes made to the content of this application do not depart from the spirit and scope of the content of this application.

70: substrate

70E2: second electrode pad

72: Adhesive layer

742: reflective layer

745: hole

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: luminous stack

77: protective layer

70E1’: Extension electrode

70E1: the first electrode pad

Claims (10)

A light-emitting element, comprising: a substrate; a light-emitting stack located on the substrate and including an active layer; a first electrode pad and a second electrode pad located on the light-emitting stack and on the same side of the substrate; A first transparent layer is located between the substrate and the first electrode pad; a second transparent layer is located between the first transparent layer and the light-emitting stack; and a hole is located in the first transparent layer and Not formed in the second transparent layer. The light-emitting device according to claim 1, further comprising a dielectric layer located between the first electrode pad and the first transparent layer. The light-emitting device according to claim 2, wherein the light-emitting stack has a side wall, and the dielectric layer is located on the side wall. The light-emitting element according to claim 1, wherein the first transparent layer has a first surface and a second surface, and the plurality of holes extend from the first surface but do not extend to the second surface. The light-emitting element according to claim 1, further comprising a conductive layer, wherein the light-emitting stack comprises a bare area, and the conductive layer is located on the bare area. The light-emitting element according to claim 5, further comprising a reflective structure, wherein the conductive layer has an upper surface covered by the reflective structure. The light-emitting element according to claim 1, wherein the second electrode pad is located on the reflective structure and overlaps the conductive layer in a vertical direction. The light-emitting element according to claim 1, further comprising a reflective layer covering a side wall of the light-emitting stack. A light-emitting element includes a light-emitting stack, including a first semiconductor layer, an active layer, and a second semiconductor layer, wherein a portion of the first semiconductor layer is exposed from the active layer and the second semiconductor layer A reflective layer located on the light-emitting stack; a first conductive layer located on the reflective layer; an insulating layer located between the reflective layer and the first conductive layer to electrically isolate the reflective layer and the first A conductive layer; and a conductive transparent layer located between the light-emitting stack and the reflective layer and has a plurality of protrusions. The light-emitting element according to claim 9, further comprising a second conductive layer on the reflective layer.

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