TWI635773B - Light-emitting device - Google Patents

Abstract

The present invention provides a light emitting element. The light-emitting element comprises: a light-emitting layer comprising an active layer; a transparent insulating layer on the light-emitting layer; and an electrode region comprising a first electrode on the transparent insulating layer; an electrical contact layer in the light-emitting layer And overlying the layer of the transparent insulating layer; wherein the electrode region further comprises an extended electrode covering the electrical contact layer, and the partially transparent insulating layer covers the portion of the electrical contact layer.

Description

Light-emitting element

The present invention discloses a light-emitting element and a method of fabricating the same, and more particularly to a light-emitting element having a transparent insulating layer.

The principle of light-emitting diode (LED) is to use energy difference between the n-type semiconductor and the p-type semiconductor to release energy in the form of light. This principle of illumination is different from incandescent lamps. The principle of heat generation, so the light-emitting diode is called a cold light source. In addition, the light-emitting diode has the advantages of high durability, long life, light weight, low power consumption, etc., so the current lighting market has high hopes for the light-emitting diode, and it is gradually replaced as a new generation of lighting tools. Light source, and is used in various fields, such as traffic signs, backlight modules, street lighting, medical equipment, etc.

Fig. 1A is a schematic view showing the structure of a conventional light-emitting element. As shown in FIG. 1A, a conventional light-emitting device 100 includes a transparent substrate 11, a semiconductor laminate 12 on a transparent substrate 11, and at least one electrode 14 on the semiconductor laminate 12, wherein the semiconductor laminate 12 is At least a first conductive semiconductor layer 120, an active layer 122, and a second conductive semiconductor layer 124 are included from top to bottom.

In addition, the above-described light-emitting element 100 can be further combined with other elements to form a light-emitting apparatus. 1B is a schematic view showing the structure of a conventional light-emitting device. As shown in FIG. 1B, a light-emitting device 200 includes a sub-mount 15 having at least one circuit 150; at least one solder 13 is located in the above-mentioned sub-carrier 15 , the light-emitting element 100 is bonded and fixed to the secondary carrier 15 by the solder 13 , and the substrate 11 of the light-emitting element 100 is electrically connected to the circuit 150 on the secondary carrier 15 ; an electrical connection structure 16 is electrically The electrode 14 of the light-emitting element 100 and the circuit 150 on the secondary carrier 15 are connected; wherein the secondary carrier 15 can be a lead frame or a large-sized mounting substrate to facilitate circuit planning of the light-emitting device 200. Improve its heat dissipation.

The present invention provides a light emitting element. The light-emitting element comprises: a light-emitting layer comprising an active layer; a transparent insulating layer on the light-emitting layer; and an electrode region comprising a first electrode on the transparent insulating layer; an electrical contact layer in the light-emitting layer And overlying the layer of the transparent insulating layer; wherein the electrode region further comprises an extended electrode covering the electrical contact layer, and the partially transparent insulating layer covers the portion of the electrical contact layer.

In order to make the description of the present invention more detailed and complete, please refer to the following description and cooperate with the drawings of Figures 2-3.

Fig. 2A is a top view of a light-emitting element according to a first embodiment of the present invention, and Fig. 2B is a cross-sectional view taken along line AA' of Fig. 2A. As shown in FIG. 2B, a light-emitting element 1 has a substrate 20; a bonding layer 21 is disposed on the substrate 20; a reflective layer 22 is disposed on the bonding layer 21; and a transparent conductive layer 23 is disposed on the reflective layer 22. a light-emitting layer 25 on the transparent conductive layer 23; an insulating layer 24 between the transparent conductive layer 23 and the light-emitting layer 25; an electrical contact layer 26 on the light-emitting layer 25; The insulating layer 28 is located on the light emitting layer 25 and contacts the electrical contact layer 26; an electrode region 27 is disposed on the transparent insulating layer 28 and the electrical contact layer 26 and includes a first electrode 271 and an extending electrode 272, wherein the first electrode 271 is located above the transparent insulating layer 28 and the extension electrode 272 is located above the electrical contact layer 26, wherein the surface area of the first electrode 271 away from the surface of the transparent insulating layer 28 is smaller than the surface area of the transparent insulating layer 28 away from the surface of the light emitting layer 25, transparent The insulating layer has a refractive index of between 1 and 3.4 and a transmittance (T%) of greater than 80%; and a second electrode 30 located below the substrate 20. The light-emitting layer 25 has a window layer 251 between the transparent conductive layer 23 and the electrode region 27; a first conductive semiconductor layer 252 between the window layer 251 and the electrode region 27; and an active layer 253 at the first Between the conductive semiconductor layer 252 and the electrode region 27; and a second conductive semiconductor layer 254 between the active layer 253 and the electrode region 27, wherein the second conductive semiconductor layer 254 is exposed and not electrically contacted with the layer 26, The surface in which the extension electrode 272 and the transparent insulating layer 28 are in contact is a roughened surface.

The electrode region 27 and/or the second electrode 30 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), indium tungsten oxide (IWO), zinc oxide (ZnO), aluminum gallium arsenide (AlGaAs), gallium nitride (GaN), gallium phosphide (GaP), gallium arsenide ( GaAs), phosphorus gallium arsenide (GaAsP), indium zinc oxide (IZO) or diamond-like carbon film (DLC). 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. As shown in FIG. 2A, the first electrode 271 is located substantially above the central region of the second conductive semiconductor layer 254. The extended electrode 272 has a first branch 2721 and a second branch 2722. The first branch 2721 is from the first electrode. 271 extends toward the boundary of the light-emitting element 1, and both ends of the second branch line 2722 extend from the both sides of the first branch line 2721 away from the first branch line, and the extending direction is substantially parallel to the boundary of the light-emitting element 1 closest thereto. As shown in FIG. 2B, the extension electrode 272 is over the electrical contact layer 26 and covers at least one surface of the electrical contact layer 26.

Electrical contact layer 26 is located between extension electrode 272 and light emitting stack 25 to form an ohmic contact between extended electrode 272 and light emitting stack 25. The electrical contact layer 26 is electrically identical to the second conductive semiconductor layer 254, and may be a semiconductor material containing more than one element selected from the group consisting of (Ga), aluminum (Al), indium (In), and arsenic. A group consisting of (As), phosphorus (P), nitrogen (N), and bismuth (Si).

The transparent insulating layer 28 is located between the first electrode 271 and the light emitting layer 25. In this embodiment, the partially transparent insulating layer 28 covers a portion of the electrical contact layer 26 to make the surface of the first electrode 271 away from the substrate relatively flat to avoid being transparent. When the insulating layer 28 does not cover the electrical contact layer 26, the difference in height at the junction causes the first electrode 271 to be recessed away from the surface of the substrate. The refractive index of the transparent insulating layer 28 is between 1 and 3.4. More preferably, the refractive index of the transparent insulating layer 28 is between 1.6 and 3.4. More preferably, the refractive index of the transparent insulating layer 28 is Between 2 and 3.4. The transparent insulating layer 28 has a transmittance (T%) of more than 80% of the wavelength of the light emitted by the light-emitting layer 25. Preferably, the transmittance (T%) is greater than 90%, and more preferably, The permeability (T%) is greater than 95%. In this embodiment, the penetration rate (T%) is greater than 98%. As shown in FIG. 2A, the transparent insulating layer 28 has an edge 281, and the edge 281 of the transparent insulating layer 28 is away from the center C of the second conductive semiconductor layer 254. The first electrode 271 has an edge 2711, the edge of the first electrode 271. 2711 is away from the center C of the second conductive type semiconductor layer 254, and a part of the edge 281 of the transparent insulating layer 28 protrudes from the edge 2711 of the first electrode 271. Further, the surface area of the electrode 271 away from the surface of the transparent insulating layer 28 is smaller than the surface area of the transparent insulating layer 28 away from the surface of the light-emitting layer 25. Therefore, the light-emitting efficiency of the light-emitting element 1 can be improved and the axial luminance of the light-emitting element 1 can be improved. Preferably, the surface area of the transparent insulating layer 28 is between 5% and 97% of the surface area of the active layer 253. In this embodiment, the surface area of the transparent insulating layer 28 is 7.7% of the surface area of the active layer 253. The transparent insulating layer 28 comprises an oxide material, wherein the oxide material includes, for example but not limited to, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO). Alumina zinc oxide (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), indium tungsten oxide (IWO), zinc oxide (ZnO), gallium phosphide (GaP), indium oxide oxide (ICO), oxidation Indium tungsten (IWO), indium titanium oxide (ITiO), indium zinc oxide (IZO), indium gallium oxide (IGO), gallium aluminum oxide (GAZO), or a combination thereof. In the present embodiment, the transparent insulating layer 28 is made of aluminum silicate (AZO), and oxygen is introduced during the process of forming the transparent insulating layer 28 on the light-emitting layer 25, and the oxygen permeation amount is adjusted and oxidized. The aluminum-zinc (AZO) film has a sheet resistance value and a transmittance of more than 80% and a low electron conductivity. Preferably, when the thickness of the transparent insulating layer 28 is not less than 800 Å, the film resistance of the transparent insulating layer 28 is greater than 10 Ω/□ (Ohm/Sq), and more preferably greater than 103 Ω/□. In the present embodiment, the film resistance of the transparent insulating layer 28 is greater than 10 6 Ω/□. The thickness of the transparent insulating layer 28 is, for example but not limited to, not less than 800 Å. In the present embodiment, the thickness of the transparent insulating layer 28 is 0.5 micrometers (μm).

The material of the light-emitting layer 25 may be a semiconductor material containing more than one element selected from the group consisting of gallium (Ga), aluminum (Al), indium (In), arsenic (As), phosphorus (P), and nitrogen (N). ) and the group formed by 矽 (Si). Commonly used materials are such as Group III nitrides such as aluminum gallium indium phosphide (AlGaInP) series and aluminum gallium indium nitride (AlGaInN) series, and zinc oxide (ZnO) series. The first conductive type semiconductor layer 252 and the second conductive type semiconductor layer 254 are different in electrical conductivity, polarity or dopant, and are used to provide a single or multi-layer structure of a semiconductor material of electrons and holes, respectively ("multilayer" means Two or more layers, the same as below). The electrical selection can be a combination of any of p-type, n-type, and i-type. The active layer 253 is located between the two portions of the electrical, polar or dopant, or between the semiconductor materials for providing electrons and holes, respectively, for the conversion of electrical energy and light energy or induced conversion. region. The structure of the active layer 253 is, for example, a single heterostructure (SH), a double heterostructure (DH), a double-side double heterostructure (DDH), or a multi-layer quantum well (multi- Quantum well; MQW). Furthermore, adjusting the logarithm of the quantum well can also change the wavelength of the illumination.

The window layer 251 is transparent to the light emitted by the active layer 253, and the material thereof may be a transparent conductive material, including but not limited to indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), and cadmium tin oxide (CTO). ), antimony tin oxide (ATO), aluminum oxide zinc (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), indium tungsten oxide (IWO), zinc oxide (ZnO), magnesium oxide (MgO), arsenic Aluminum gallium (AlGaAs), gallium nitride (GaN), gallium phosphide (GaP) or indium zinc oxide (IZO).

The material of the transparent conductive layer 23 is transparent to the light emitted by the light-emitting layer 25, and can increase ohmic contact between the window layer 251 and the reflective layer 22 as well as current conduction and diffusion, and form an omnidirectional mirror with the reflective layer 22 (Omni -Directional Reflector, ODR). 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), indium tungsten oxide (IWO), 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 of the above.

The insulating layer 24 has a light transmittance of greater than 90% for the light-emitting layer 25 and a refractive index of less than 1.4, preferably between 1.3 and 1.4. The material of the insulating layer 24 may include, but is not limited to, a non-oxide insulating material such as benzocyclobutene (BCB), cycloolefin polymer (COC), fluorocarbon polymer (Fluorocarbon Polymer), tantalum nitride (SiN _x ). Calcium fluoride (CaF ₂ ) or magnesium fluoride (MgF ₂ ); the material of the insulating layer 24 may comprise a halide or a compound of Group IIA and Group VII, such as calcium fluoride (CaF ₂ ) or magnesium fluoride (MgF) ₂ ). In this embodiment, the material of the insulating layer 24 is magnesium fluoride (MgF ₂ ). The refractive index of the insulating layer 24 is smaller than the refractive index of the window layer 251 and the transparent conductive layer 23, so the critical angle of the interface between the window layer 251 and the insulating layer 24 is smaller than the critical angle of the interface between the window layer 251 and the transparent conductive layer 23, so the light-emitting stack After the light emitted by the layer 25 is directed toward the insulating layer 24, the probability of total reflection at the interface between the window layer 251 and the insulating layer 24 increases.

The reflective layer 22 can reflect light from the light emitting stack 25, 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 21 can connect the substrate 20 to the reflective layer 22 and can have a plurality of subordinate layers (not shown). The material of the bonding layer 21 may be a transparent conductive material or a metal material, and 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 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 25 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, Al2O3, Zinc Oxide (ZnO) ) or aluminum nitride (AlN) or the like. 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 ).

Compared with a light-emitting element which does not include the transparent insulating layer 28 and has the same structure, the current of the light-emitting element 1 of the present embodiment is higher by about 6 to 7%, so that the light-emitting efficiency is improved. In another embodiment, the transparent insulating layer 28 has a thickness of 1 μm, and the current is higher than that of the transparent insulating layer 28 having a thickness of 0.5 μm. In still another embodiment, the thickness of the transparent insulating layer 28 is 2 μm, and the current of the light-emitting element having a thickness of 1 μm compared with the transparent insulating layer 28 is about 5% higher, so that the light-emitting efficiency is higher.

FIG. 3 is a schematic exploded view of a light bulb according to a second embodiment of the present invention. The light bulb 2 includes a lamp cover 41, a lens 42, a light-emitting module 44, a lamp holder 45, a heat-dissipating fin 46, a joint portion 47 and an electrical connector 48. The light-emitting module 44 includes a carrier 43 and includes at least one of the light-emitting elements 1 of the above embodiment on the carrier 43.

The above figures and descriptions are only corresponding to specific embodiments, however, the elements, embodiments, design criteria, and technical principles described or disclosed in the various embodiments are inconsistent, contradictory, or difficult to implement together. In addition, we may use any reference, exchange, collocation, coordination, or merger as required.

Although the invention has been described above, it is not intended to limit the scope of the invention, the order of implementation, or the materials and process methods used. Various modifications and variations of the present invention are possible without departing from the spirit and scope of the invention.

1‧‧‧Lighting elements

2‧‧‧Light bulb

11‧‧‧Transparent substrate

12‧‧‧Semiconductor laminate

13‧‧‧ solder

14‧‧‧Electrode

15‧‧‧ times carrier

16‧‧‧Electrical connection structure

20‧‧‧Substrate

21‧‧‧Bonded layer

22‧‧‧reflective layer

23‧‧‧Transparent conductive layer

24‧‧‧Insulation

25‧‧‧Lighting laminate

26‧‧‧Electrical contact layer

27‧‧‧Electrode zone

28‧‧‧Transparent insulation

30‧‧‧second electrode

41‧‧‧shade

42‧‧‧ lens

43‧‧‧ Carrier Board

44‧‧‧Lighting module

45‧‧‧ lamp holder

46‧‧‧Heat fins

47‧‧‧Combination Department

48‧‧‧Electrical connector

100‧‧‧Lighting elements

120‧‧‧First Conductive Semiconductor Layer

122‧‧‧Active layer

124‧‧‧Second conductive semiconductor layer

150‧‧‧ Circuit

200‧‧‧Lighting device

251‧‧‧Window layer

252‧‧‧First Conductive Semiconductor Layer

253‧‧‧Active layer

254‧‧‧Second conductive semiconductor layer

271‧‧‧First electrode

272‧‧‧Extended electrode

281‧‧‧ edge

2711‧‧‧ edge

2721‧‧‧first line

2722‧‧‧Second branch

C‧‧‧ Center

FIG. 1A is a schematic view showing the structure of a conventional light-emitting device, and FIG. 1B is a schematic structural view of a conventional light-emitting device.

2A is a top view of the light-emitting element of the first embodiment of the present invention, and FIG. 2B is a cross-sectional view taken along line AA' of FIG. 2A.

Figure 3 is a schematic exploded view of a bulb according to a second embodiment of the present invention.

no.

Claims (10)

A light-emitting element comprising: a light-emitting layer comprising an active layer; a transparent insulating layer on the light-emitting layer; and an electrode region comprising a first electrode on the transparent insulating layer; an electrical contact a layer on the light-emitting layer and contacting the transparent insulating layer; wherein the electrode region further comprises an extension electrode covering the electrical contact layer, and a portion of the transparent insulating layer covers a portion of the electrical contact layer. The light-emitting element according to claim 1, wherein the transparent insulating layer has a refractive index of between 1 and 3.4. The light-emitting element of claim 1, wherein the electrical contact layer comprises a semiconductor material. The light-emitting element according to claim 1, wherein the transparent insulating layer has a thickness of not less than 800 Å. The light-emitting element of claim 1, wherein the transparent insulating layer comprises an oxide material. The light-emitting element according to claim 1, wherein the transparent insulating layer has a transmittance (T%) of more than 80%. The light-emitting element of claim 1, wherein the transparent insulating layer has an edge and the first electrode has an edge, and in a cross-sectional view of the light-emitting element, a portion of the transparent insulating layer is the edge Projecting from the edge of the first electrode. The light-emitting element of claim 1, further comprising an insulating layer under the light-emitting layer. The light-emitting element of claim 8, wherein the insulating layer has a refractive index of less than 1.4. The light-emitting element of claim 8, wherein the reflective layer is located below the insulating layer.