CN101315962A - Light emitting diode device and manufacturing method thereof - Google Patents

Abstract

The present invention discloses a light emitting diode device, which includes an epitaxial stack, a micro-nano roughened structure layer and an anti-reflection layer. The epitaxial stack has a first semiconductor layer, a light emitting layer and a second semiconductor layer in sequence. The micro-nano roughened structure layer is disposed on the first semiconductor layer of the epitaxial stack. The anti-reflection layer is disposed on the micro-nano roughened structure layer. In addition, the present invention also discloses a method for manufacturing the light emitting diode device.

Description

Light emitting diode device and manufacturing method thereof

technical field

The invention relates to a light-emitting diode device with a micro-nano structure current diffusion layer and a manufacturing method thereof.

Background technique

A light-emitting diode (LED) device is a light-emitting element made of semiconductor materials. Since the light-emitting diode device is a cold light emitting device, it has the advantages of low power consumption, long component life, fast response speed, etc., and it is easy to make extremely small or array components due to its small size. Therefore, with the continuous advancement of technology in recent years, , and its application range covers indicator lights of computers or home appliances, backlights of liquid crystal display devices, traffic signs or vehicle lights.

However, the current LED devices still have the problems of poor luminous efficiency and low brightness. The reason for the poor luminous efficiency is that the light emitted by the light-emitting diode is omnidirectional, rather than a single beam focused on a certain place. In addition, only part of the light emitted by the LED can be emitted, and the rest of the light will be absorbed due to reflection. In this way, in addition to reducing the brightness of the LED device, it also increases the heat generated by it.

In general, LED devices can be in different forms such as flip-chip, vertical or front-side. In order to solve the problem of reducing light extraction efficiency due to reflection. Please refer to FIG. 1 , taking a vertical light-emitting diode device as an example, the light-emitting diode device 1 forms an n-type semiconductor doped layer 121, a light-emitting layer (active layer) 122 and a p-type semiconductor doped layer 123 in sequence on the surface of a substrate 11. Next, a current diffusion layer 13 is formed on the p-type semiconductor doped layer 123 , and the first electrode 14 and the second electrode 15 are respectively disposed on the current diffusion layer 13 and the other surface of the substrate 11 .

In the above structure, the light emitted by the light-emitting layer 122 needs to pass through the second semiconductor layer 123 and the current diffusion layer 13 before exiting the light-emitting diode device 1, and due to the refractive index of the second semiconductor layer 123, the current diffusion layer 13 and air There is no proper matching, so it will cause total reflection of light during the exit process, thus reducing the light extraction efficiency.

Therefore, how to provide a light emitting diode device and its manufacturing method that can effectively reduce the total reflection of light to increase the light extraction efficiency is one of the current important issues.

Contents of the invention

In view of the above problems, the object of the present invention is to provide a light emitting diode device capable of reducing total reflection of light and uniformly distributing current and a manufacturing method thereof.

Therefore, to achieve the above object, the present invention provides a light emitting diode device comprising an epitaxial stack, a micro-nano roughened structure layer and an anti-reflection layer. The epitaxial stack has a first semiconductor layer, a light emitting layer and a second semiconductor layer in sequence. The micro-nano roughened structure layer is arranged on the first semiconductor layer of the epitaxial stack. The anti-reflection layer is arranged on the micro-nano roughened structure layer.

To achieve the above object, the present invention further provides a method for manufacturing a light emitting diode, which includes the following steps: forming a first semiconductor layer on an epitaxial substrate; forming a light emitting layer on the first semiconductor layer; forming a second semiconductor layer on the light emitting layer layer, wherein the first semiconductor layer, the light-emitting layer and the second semiconductor layer constitute an epitaxial stack; a micro-nano roughened structure layer is formed on the first semiconductor layer of the epitaxial stack; and an anti-reflection layer is formed on the micro-nano roughened structure layer layer.

As in the above-mentioned light-emitting diode and its manufacturing method, wherein the refractive index of the micro-nano roughened structure layer is between the refractive index of the epitaxial layer and the refractive index of air, and the refractive index of the anti-reflection layer is between the micro-nano roughened structure. between the refractive index of the layer and that of air. The anti-reflection layer is composed of a plurality of micro-nano particles, and the particle size of each micro-nano particle is between 50 nanometers and 50 microns.

Based on the above, the light-emitting diode and its manufacturing method of the present invention use the micro-nano roughened structure layer and the anti-reflection layer to reduce the total reflection loss, and achieve refractive index matching through it, so as to increase the light extraction efficiency of the light-emitting diode device.

Description of drawings

FIG. 1 is a schematic diagram of a known LED device.

FIG. 2 is a flowchart of a manufacturing method of a light emitting diode device according to a first embodiment of the present invention.

FIG. 3A to FIG. 3K are schematic diagrams of the LED device matched with FIG. 2 .

FIG. 4 is a flowchart of a method of manufacturing a light emitting diode device according to a second embodiment of the present invention.

FIG. 5A to FIG. 5G are schematic diagrams of the LED device matched with FIG. 4 .

Explanation of reference signs

1, 2, 2’, 3, 3’: LED devices

11: Substrate

121: N-type doped layer

122, 212, 312: light-emitting layer

123: P-type doped layer

13: Transparent conductive layer

14, 271, 371: first electrode

15, 272, 372: second electrode

20, 30: Epitaxial substrate

21: Epitaxial stack

211, 311: the first semiconductor layer

213, 313: second semiconductor layer

22, 32: current spreading layer

23, 33: reflective layer

24: thermal insulation layer

25, 35: thermal paste layer

26, 36: Thermally conductive substrate

271, 371: first electrode

272, 372: second electrode

29, 39: anti-reflection layer

28, 38: micro-nano roughened structure layer

Detailed ways

The light emitting diode device and its manufacturing method according to preferred embodiments of the present invention will be described below with reference to related drawings.

[first embodiment]

Please refer to FIG. 2 , the method for manufacturing a light emitting diode device according to the first embodiment of the present invention includes step S10 to step S19 . Please refer to FIG. 3A to FIG. 3K simultaneously below.

As shown in FIG. 3A , step S10 forms a first semiconductor layer 211 on the epitaxial substrate 20 , forms a light emitting layer 212 on the first semiconductor layer 211 , and forms a second semiconductor layer 213 on the light emitting layer 212 . Wherein, the first semiconductor layer 211 , the light emitting layer 212 and the second semiconductor layer 213 constitute an epitaxial stack 21 . In this embodiment, the first semiconductor layer 211 and the second semiconductor layer 213 can be a P-type epitaxial layer and an N-type epitaxial layer, of course, they can also be interchanged, which is not limited here.

As shown in FIG. 3B , step S11 forms a current spreading layer 22 on the second semiconductor layer 213 . In this embodiment, the material of the current spreading layer 22 may be indium tin oxide (Indium tin oxide, ITO), aluminum doped zinc oxide (aluminum doped zinc oxide, AZO), zinc oxide (ZnO), nickel/gold (Ni /Au) or antimony tin oxide, which is not limited here, and the priority is to be able to spread the current uniformly.

As shown in FIG. 3C , in step S12 , a reflective layer 23 is formed on the current spreading layer 22 . In this embodiment, the reflective layer 23 can be a metal reflective layer. In addition to having a reflective effect, it can also provide a good heat conduction path, and its material can be selected from platinum, gold, silver, palladium, nickel, chromium, titanium, chromium /gold, nickel/gold, titanium/gold, titanium/silver, chromium/platinum/gold, and combinations thereof. In addition, the reflective layer 23 can be an optical reflective element composed of a dielectric film with high and low refractive index, a metal reflective layer, a metal dielectric reflective layer, or an optical reflective element composed of micro-nanospheres, that is, the reflective layer 23 It can be combined or stacked from various materials.

As shown in FIG. 3D , step S13 forms a thermally conductive insulating layer 24 on the reflective layer 23 . In this embodiment, the material of the thermally conductive insulating layer 24 is an insulating material with a thermal conductivity greater than or equal to 150 W/mK (watt/meter·Kelvin temperature), such as aluminum nitride or silicon carbide. In addition, the refractive index of the thermally conductive insulating layer 24 is between the refractive index of the epitaxial stack 21 and the refractive index of air.

As shown in FIG. 3E , step S14 combines the thermally conductive substrate 26 with the thermally conductive insulating layer 24 through the thermally conductive adhesive layer 25 . In this embodiment, the material of the thermally conductive adhesive layer 25 can be pure metal, alloy metal, conductive material, non-conductive material or organic material, which can be selected from gold, solder paste, tin-silver paste, silver paste and combinations thereof group. In addition, in this embodiment, the material of the thermally conductive substrate 26 may be selected from the group consisting of silicon, gallium arsenide, gallium phosphide, silicon carbide, boron nitride, aluminum, aluminum nitride, copper and combinations thereof.

As shown in FIG. 3F , step S15 turns over the LED device 2 formed in step S14 and removes the epitaxial substrate 20 .

As shown in FIG. 3G , step S16 removes part of the epitaxial stack 21, that is, it removes part of the first semiconductor layer 211, part of the light emitting layer 212 and part of the second semiconductor layer 213 to expose part of the The current spreading layer 22 .

As shown in FIG. 3H , in step S17, the first electrode 271 is electrically connected to a part of the first semiconductor layer 212, and the second electrode 272 is formed to connect with the parts exposed to the first semiconductor layer 211, the light emitting layer 212 and the second semiconductor layer 213. The current spreading layer 22 is electrically connected.

In step S18, on another part of the first semiconductor layer 211, for example but not limited to stacking process, sintering process, anodic aluminum oxide process (AAO), nanoimprint process, hot pressing process, etching process or electron beam exposure process (E- beam writer) to form a micro-nano roughened structure layer 28. The micro-nano roughened structure layer 28 can be nanospheres, nanopillars, nanoholes, nanodots, nanowires or nano-concave-convex structures. In this embodiment, the refractive index of the micro-nano roughened structure 28 is greater than the refractive index of air (about 1), and smaller than the refractive index of the epitaxial stack 31 (about 2.5), and the material of the micro-nano roughened structure 28 Can be selected from aluminum oxide (Al ₂ O ₃ ), silicon nitride (Si ₃ N ₄ ), tin dioxide (SnO ₂ ), silicon dioxide (SiO ₂ ), resin, polycarbonate (polycarbonate) and A group composed of combinations. It should be noted that the micro/nano roughened structure layer 28 may be additionally formed on the first semiconductor layer 211 , as shown in FIG. 3I . Alternatively, the micro-nano roughened structure layer 28 may be directly integrally formed on the first semiconductor layer 211 , as shown in FIG. 3J .

In addition, as shown in FIG. 3K , step S19 further forms an anti-reflection layer 29 on the micro-nano roughened structure layer 28 to form a front-side light-emitting diode device 2'. It should be noted that FIG. 3K takes the micro-nano roughened structure layer 28 shown in FIG. 3I as an example. Of course, step S19 may also take the micro-nano roughened structure layer 28 shown in FIG. 3J as an example. In this embodiment, the anti-reflection layer 29 is composed of a plurality of micro-nano particles, and the particle size of each micro-nano particle is between 50 nanometers and 50 micrometers. In addition, the refractive index of the anti-reflection layer is between the refractive index of the micro-nano roughened structure layer and the refractive index of air. Meanwhile, the anti-reflection layer 29 may be a structure formed of single-layer or multi-layer dielectric thin films.

It is worth mentioning that the above steps are not limited to this order, and the steps can be exchanged according to the needs of the process.

[Second embodiment]

Referring to FIG. 4 , the method for manufacturing a light emitting diode device (a vertical light emitting diode) according to a second embodiment of the present invention includes steps S20 to S27. Please refer to FIG. 5A to FIG. 5G in the following.

As shown in FIG. 5A , step S20 forms an epitaxial stack 31 on the epitaxial substrate 30 , and the epitaxial stack 31 is sequentially composed of a first semiconductor layer 311 , a light emitting layer 312 and a second semiconductor layer 313 . Wherein, in this embodiment, the first semiconductor layer 311 and the second semiconductor layer 213 can be a P-type epitaxial layer and an N-type epitaxial layer respectively, of course, they can also be interchanged, which is not limited here.

As shown in FIG. 5B , the results of performing steps S21 to S23 are displayed. Step S21 forms the current spreading layer 32 on the second semiconductor layer 313 . In this embodiment, the material of the current spreading layer 32 may be indium tin oxide (Indium tin oxide, ITO), aluminum doped zinc oxide (aluminum doped zinc oxide, AZO), zinc oxide (ZnO), nickel/gold (Ni/ Au) or antimony tin oxide, which is not limited here, and the priority is to be able to spread the current uniformly.

Step S22 forms the reflective layer 33 on the current spreading layer 32 . In this embodiment, the reflective layer 33 can be a metal reflective layer. In addition to having a reflective effect, it can also provide a good heat conduction path, and its material can be selected from platinum, gold, silver, palladium, nickel, chromium, titanium, chromium /gold, nickel/gold, titanium/gold, titanium/silver, chromium/platinum/gold, and combinations thereof. And the reflective layer 33 can be formed by combining or stacking various materials.

Step S23 combines the thermally conductive substrate 36 with the reflective layer 33 through the thermally conductive adhesive layer 35 . In this embodiment, the material of the thermally conductive adhesive layer 35 can be pure metal, alloy metal, conductive material, non-conductive material or organic material, which can be selected from gold, solder paste, tin-silver paste, silver paste and combinations thereof group. In addition, in this embodiment, the material of the thermally conductive substrate 36 may be selected from the group consisting of silicon, gallium arsenide, gallium phosphide, silicon carbide, boron nitride, aluminum, aluminum nitride, copper and combinations thereof.

Next, as shown in FIG. 5C , step S24 turns over the LED device 3 formed in step S23 and removes the epitaxial substrate 30 .

As shown in FIG. 5D , in step S25 , a first electrode 371 is provided on a portion of the first semiconductor layer 311 , and a second electrode 372 is provided on the surface 361 of the thermally conductive substrate 36 opposite to the thermally conductive adhesive layer 35 .

As shown in FIG. 5E , in step S26 , on another part of the first semiconductor layer 311 , for example but not limited to stacking process, sintering process, anodic aluminum oxide process (AAO), nanoimprinting process, hot pressing process, etching process or electronic The micro-nano roughened structure layer 38 is formed by a beam exposure process (E-beam writer). The micro-nano roughened structure layer 38 can be nanospheres, nanopillars, nanoholes, nanodots, nanowires or nano-concave-convex structures. In this embodiment, the refractive index of the micro-nano roughened structure 38 is greater than the refractive index of air (about 1), and smaller than the refractive index of the epitaxial stack 31 (about 2.5). The material of the micro-nano roughened structure 28 can be selected from aluminum oxide (Al ₂ O ₃ ), silicon nitride (Si ₃ N ₄ ), tin dioxide (SnO ₂ ), silicon dioxide (SiO ₂ ), resin , polycarbonate (polycarbonate) and combinations thereof. It should be noted that the micro/nano roughened structure layer 38 may be additionally formed on the first semiconductor layer 311 , as shown in FIG. 5E . Alternatively, the micro/nano roughened structure layer 38 may be directly integrally formed on the first semiconductor layer 311 , as shown in FIG. 5F .

In addition, as shown in FIG. 5G , in step S27, an anti-reflection layer 39 is further formed on the micro/nano roughened structure layer 38 to form a vertical light emitting diode device 3'. It should be noted that FIG. 5G takes the micro-nano roughened structure layer 38 shown in FIG. 5E as an example. Of course, step S27 may also take the micro-nano roughened structure layer 38 shown in FIG. 5F as an example. In this embodiment, the anti-reflection layer 39 is composed of a plurality of micro-nano particles, and the particle size of each micro-nano particle is between 50 nanometers and 50 micrometers. In addition, the refractive index of the anti-reflection layer is between the refractive index of the micro-nano roughened structure layer and the refractive index of air. Meanwhile, the anti-reflection layer 29 may be a structure formed of single-layer or multi-layer dielectric thin films.

It should be noted here that the execution of each step is not limited to the above sequence, and the steps can be exchanged according to the requirements of the process.

In summary, according to the light-emitting diode and its manufacturing method of the present invention, the micro-nano roughened structure layer and the anti-reflection layer are used to reduce the total reflection loss, and at the same time achieve refractive index matching through it to increase the light extraction efficiency of the light-emitting diode device .

The above descriptions are illustrative only, not restrictive. Any equivalent modifications or changes made without departing from the spirit and scope of the present invention shall be included in the appended claims.

Claims (19)

1, a kind of light-emitting diode assembly comprises:

Extension lamination has first semiconductor layer, luminescent layer and second semiconductor layer in regular turn; And

Micro-nano alligatoring structure sheaf is arranged on this first semiconductor layer of this extension lamination;

Wherein the refractive index of this micro-nano alligatoring structure sheaf is between the refractive index of the refractive index of this extension lamination and air.

2, light-emitting diode assembly as claimed in claim 1 also comprises anti-reflecting layer, and it is arranged on this micro-nano alligatoring structure sheaf, and the refractive index of this anti-reflecting layer is between the refractive index of the refractive index of this micro-nano alligatoring structure sheaf and air.

3, light-emitting diode assembly as claimed in claim 2, wherein this anti-reflecting layer comprises a plurality of micro-and nano-particles, wherein whenever the particle diameter of this micro-and nano-particles between 50 nanometers to 50 micron; Perhaps, this anti-reflecting layer can be the structure of the dielectric medium film formation of single or multiple lift.

4, light-emitting diode assembly as claimed in claim 2, wherein this first semiconductor layer is P type epitaxial loayer or N type epitaxial loayer, and this second semiconductor layer is N type epitaxial loayer or P type epitaxial loayer.

5, light-emitting diode assembly as claimed in claim 2, wherein this micro-nano alligatoring structure sheaf and this first semiconductor layer are formed in one, or different each other two layers.

6, light-emitting diode assembly as claimed in claim 2, wherein this micro-nano alligatoring structure sheaf comprises nanosphere, nano-pillar, nano aperture, nano dot, nano wire or nano concavo-convex structure at least, and perhaps the material of this micro-nano alligatoring structure sheaf is selected from alundum (Al, silicon nitride, tin ash, silicon dioxide, resin, Merlon, indium tin oxide, Al-Doped ZnO, zinc oxide and group that combination constituted thereof.

7, light-emitting diode assembly as claimed in claim 2 also comprises:

Heat-conducting substrate is relative with this second semiconductor layer and establish;

Heat conduction sticking layer is arranged between this heat-conducting substrate and this second semiconductor;

The reflector is arranged between this heat conduction sticking layer and this second semiconductor layer; And

Current-diffusion layer is arranged between this reflector and this second semiconductor layer.

8, light-emitting diode assembly as claimed in claim 7, some of these first semiconductor layers are exposed to this micro-nano alligatoring structure sheaf and this anti-reflecting layer, and this light-emitting diode assembly also comprises:

First electrode electrically connects with this first semiconductor layer that is exposed to this micro-nano alligatoring structure sheaf and this anti-reflecting layer; And

Second electrode electrically connects with this heat-conducting substrate.

9, light-emitting diode assembly as claimed in claim 7, also comprise the heat conductive insulating layer, it is arranged between this heat conduction sticking layer and this reflector, some of these first semiconductor layers are exposed to this micro-nano alligatoring structure sheaf and this anti-reflecting layer, or the part this second semiconductor layer be exposed to this luminescent layer, this first semiconductor layer, this micro-nano alligatoring structure sheaf and this anti-reflecting layer and this light-emitting diode assembly, also comprise:

First electrode electrically connects with this first semiconductor layer that is exposed to this micro-nano alligatoring structure sheaf and this anti-reflecting layer; And

Second electrode electrically connects with this second semiconductor layer that is exposed to this luminescent layer, this first semiconductor layer, this micro-nano alligatoring structure sheaf and this anti-reflecting layer.

10, light-emitting diode assembly as claimed in claim 9, wherein the material of this heat conductive insulating layer is the insulating material of the coefficient of heat conduction more than or equal to 150 watts/meter Degree Kelvins, as aluminium nitride or carborundum.

11, a kind of manufacture method of light-emitting diode assembly comprises:

On epitaxial substrate, form first semiconductor layer;

On this first semiconductor layer, form luminescent layer;

Form second semiconductor layer on this luminescent layer, wherein this first semiconductor layer, this luminescent layer and this second semiconductor layer constitute extension lamination; And

On this first semiconductor layer of this extension lamination, form micro-nano alligatoring structure sheaf;

Wherein the refractive index of this micro-nano alligatoring structure sheaf is between the refractive index of the refractive index of this extension lamination and air.

12, manufacture method as claimed in claim 11, after forming this micro-nano alligatoring structure sheaf, further comprising the steps of:

On this micro-nano alligatoring structure sheaf, form anti-reflecting layer;

Wherein the refractive index of this anti-reflecting layer is between the refractive index of the refractive index of this micro-nano alligatoring structure sheaf and air, and this anti-reflecting layer comprises a plurality of micro-and nano-particles, and wherein the particle diameter of each this micro-and nano-particles is between 50 nanometers to 50 micron; Perhaps, this anti-reflecting layer can be the formed structure of dielectric medium film of single or multiple lift.

13, manufacture method as claimed in claim 12, wherein this micro-nano alligatoring structure sheaf forms to pile up technology, sintering process, anodised aluminium technology, nano-imprint process, heat pressing process, etch process or electron beam exposure technology.

14, manufacture method as claimed in claim 12, it is further comprising the steps of:

On this second semiconductor layer, form current-diffusion layer; And

On this current-diffusion layer, form the reflector;

Wherein the material of this current-diffusion layer is indium tin oxide, Al-Doped ZnO, zinc oxide, nickel/gold or antimony tin, the material in this reflector is selected from the group that platinum, gold, silver, palladium, nickel, chromium, titanium, chromium/gold, nickel/gold, titanium/gold, titanium/silver, chromium/platinum/gold and combination thereof are constituted, perhaps serve as reasons optical reflection element, metallic reflector, metal and dielectric reflector that dielectric medium film with high low-refraction formed or the optical reflection element of being made up of micro-nano ball of this reflector.

15, manufacture method as claimed in claim 14, it is further comprising the steps of:

Heat-conducting substrate is combined with this reflector by heat conduction sticking layer; And

This light-emitting diode assembly overturns;

Wherein this heat-conducting substrate is electrically-conductive backing plate or insulated substrate, and the material of this heat-conducting substrate is selected from silicon, GaAs, gallium phosphide, carborundum, boron nitride, aluminium, aluminium nitride, copper and group that combination constituted thereof.

16, manufacture method as claimed in claim 15, wherein the material of this heat conduction sticking layer is selected from gold, tin cream, tin silver paste, silver paste and group that combination constituted thereof, and perhaps the material of this heat conduction sticking layer is simple metal, alloying metal, electric conducting material, non-conducting material or organic material.

17, manufacture method as claimed in claim 15, it also comprises:

Remove this epitaxial substrate;

On this first semiconductor layer of part, first electrode is set; And

With respect to the surface of this heat conduction sticking layer second electrode is set at this heat-conducting substrate;

Wherein this micro-nano alligatoring structure sheaf is arranged on this first semiconductor layer of another part.

18, manufacture method as claimed in claim 14, it is further comprising the steps of:

On this reflector, form the heat conductive insulating layer;

Heat-conducting substrate is combined with this heat conductive insulating layer by heat conduction sticking layer; And

This light-emitting diode assembly overturns.

19, manufacture method as claimed in claim 18, it is further comprising the steps of:

Remove this epitaxial substrate;

Remove the extension lamination of part, to expose this current-diffusion layer of part;

On this first semiconductor layer of part, first electrode is set; And

On this current-diffusion layer of the part that is exposed to this extension lamination, second electrode is set.

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