CN2909538Y - High efficience high brightness reflecting LED - Google Patents

High efficience high brightness reflecting LED Download PDF

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Publication number
CN2909538Y
CN2909538Y CNU200620116351XU CN200620116351U CN2909538Y CN 2909538 Y CN2909538 Y CN 2909538Y CN U200620116351X U CNU200620116351X U CN U200620116351XU CN 200620116351 U CN200620116351 U CN 200620116351U CN 2909538 Y CN2909538 Y CN 2909538Y
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layer
conductivity type
metal
light
substrate
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CNU200620116351XU
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邹德恕
张剑铭
沈光地
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Beijing TimesLED Technology Co.,Ltd.
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Beijing University of Technology
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Abstract

A high-efficiency and high-brightness total reflection light-emitting diode belongs to semiconductor optoelectronic technology field. The utility model includes in turn: a graphic electrode(517), the first conducting ohmic contact layer(304), the first conducting current spreading layer(305), the first conducting bottom confinement layer(306), an undoping active region(307), the second conducting top confinement layer(308), the second conducting current spreading layer(309), the second conducting ohmic contact layer(310), a medium layer, a metal layer(506), a metal solder layer(505), a barrier layer(402), a baseplate underlay(401), a metal electrode(518). The medium layer and metal layer (506) are combined as a reflector. The baseplate(401), barrier layer(402) and metal solder layer(505) compose a baseplate(400). This invention solves the problem that the bandwidth of DBR reflectance angle is limited and the extension underlay absorbs photons, and reduces thermal resistance, is applicable to work under high current density injection, increases luminous efficiency, carries out high power output of the light.

Description

Efficient full-bright all-reflection light-emitting-diode
Technical field
The utility model relates to a kind of light-emitting diode, and particularly efficient full-bright all-reflection light-emitting-diode and manufacture method belong to field of semiconductor photoelectron technique.
Background technology
Since the early stage appearance of AlGaInP redness, yellow light-emitting diode in generation nineteen ninety, the research and development of after a while GaN blueness, green and white light-emitting diode, these light-emitting diodes have been widely used on a lot of efficient solid-state illumination fields, for example full color screen display, lamps for vehicle, backlight, traffic lights, view and normal lighting etc.These efficient LEDs begin to replace traditional incandescent lamp and Halogen lamp LED in recent years, but because its luminous efficiency is still not high enough, are not enough to replace fluorescent lamp, metal halide lamp, high pressure and low-pressure sodium lamp.Though can be with internal quantum (Internal quantum efficiency, η in present single crystal technology Int) be promoted to 90% or even higher, external quantum efficiency (External quantum efficiency, η Ext) but have only 10% or lower.How further improving the luminous efficiency of light-emitting diode, by extracting in various modular constructions and the manufacture method, for the brightness and efficient that improve light-emitting diode, is a main research and development emphasis and technical bottleneck with the inner light that produces of light-emitting diodes.
As figure (1) is traditional usefulness metal organic chemical compound vapor deposition (MOCVD) technology epitaxially grown existing conventional AlGaInP Multiple Quantum Well (MQW) light-emitting diode 100 cross-sectional view on the GaAs substrate.This AlGaInP Multiple Quantum Well (MQW) light emitting diode construction comprises the n-GaAs substrate, n-GaAs resilient coating, n-AlInP lower limit layer (n-cladding layer), (Al of non-doping 0.15Ga 0.85) 0.5In 0.5P MQW active area, p-AlInP upper limiting layer (p-cladding layer), p type ohmic contact layer, base plane Metal Contact and upper surface electrode.Electronics and hole be at the active area recombination luminescence, the only random orientation that sends.For the light-emitting diode of this structure, several effects limit the have been arranged extraction efficiency of light: semi-conducting material and the refringence internal reflection that causes bigger than normal between the medium around it, metal electrode block GaAs substrate absorption etc.Like this, the photon of the light directive upper surface that active area sends has certain probability to extract, and the photon major part of propagating is downwards absorbed by the GaAs substrate.Therefore, even very high internal quantum is arranged, external quantum efficiency also only has 4-5%.
In order to improve the extraction efficiency of light, the photon of propagating downwards and the photon of upper surface reflected back semi-conducting material inside also can major part be extracted, reduce the absorption of GaAs substrate, people's Bragg mirror (Distributed Bragg Reflectors have grown between GaAs substrate and active area, DBRs), so that the light at the back side is reflexed to chip surface.Fig. 2 is existing AlGaInP Multiple Quantum Well (MQW) light-emitting diode 200 cross-sectional view that have high reflectance DBR.Just in the DBRs structure of having grown between GaAs substrate and active area on the basis of Fig. 1 structure, the current extending of having grown under p type ohmic contact layer also is that Window layer is come effective extend current.But because the reflectivity angle limited bandwidth of actual DBRs speculum, only big to light reflectivity near normal incidence, light reflectivity beyond this scope is sharply descended,, still have the light of considerable part to be absorbed by the GaAs substrate so can not effectively reflect to absorbing the light that substrate GaAs propagates.
In addition, because of the AlGaInP light-emitting diode to get optical efficiency very low, most of photon energy has converted heat to, and the thermal conductivity of GaAs substrate is very low, the heat that chip internal produces can not in time conduct, cause chip temperature to raise, reduce internal quantum efficiency, the AlGaInP LED that has limited this structure can only use in low power range.
The utility model content
The purpose of this utility model is to provide a kind of efficient full-bright all-reflection light-emitting-diode and preparation method thereof, to address the above problem.
The technical solution of the utility model is characterized in that referring to Fig. 3-Fig. 7: comprise pattern electrodes 517, the first conductivity type ohmic contact layers 304 successively, the first conductivity type current extension layer, 305, the first conductivity type lower limit layers 306, the active area 307 of non-doping, the second conductivity type upper limiting layer, 308, the second conductivity type current extension layers, 309, the second conductivity type ohmic contact layers 310, dielectric layer, metal level 506, the metal welding bed of material 505, barrier layer 402, substrate substrate 401, metal electrode 518.Wherein:
Dielectric layer and metal level 506 are united as reflective mirror; Substrate substrate 401, barrier layer 402 and the metal welding bed of material 505 composing bases 400.
Dielectric layer is non-conductive transparent dielectric layer 515, or dielectric layer is a conductive, transparent dielectric layer 615.
Metal level 506 is Au, AuBe, AuZnAu, Ag or Al.
The metal welding bed of material 505 is gold-tin alloy, indium metal, silver-colored ashbury metal or metallic tin.
Barrier layer 402 is Ti/TiN, Ti/Pt or Ta/TaN.
Substrate substrate 401 is heavy doping Si, GaAs, pottery or metal.
Pattern electrodes 517 is TiAu, TiAl or AuGeNi.
The figure of pattern electrodes is annular, back-shaped, slotting finger-type, star, M shape.
Metal electrode 518 is TiAu or AuGeNi.
The utility model is made the method for efficient full-bright all-reflection light-emitting-diode, comprises the manufacture method of LED epitaxial slice and substrate, it is characterized in that:
1) with the MOCVD growth technology LED epitaxial slice 300 of on the GaAs substrate, growing, comprise the first conductivity type substrate 301 successively, first conductivity type buffer layer, 302, the first conductivity type etch stop layer, 303, the first conductivity type ohmic contact layers 304, the first conductivity type current extension layer 305, the first conductivity type lower limit layer 306, active area 307, the second conductivity type upper limiting layers 308 of non-doping, the second conductivity type current extension layer, 309, the second conductivity type ohmic contact layers 310;
2) dielectric layer deposited on LED epitaxial slice 300 second conductivity type ohmic contact layers 310 when dielectric layer is non-conductive transparent dielectric layer 515, etches grid, when dielectric layer is a conductive, transparent dielectric layer 615, and etching not then;
3) deposited metal 506 on aforementioned dielectric layer, metal level and dielectric layer are united as reflective mirror;
4) growth one deck barrier layer 402 on substrate 400 substrates;
5) depositing metal solder layer 505 on barrier layer 402;
6) the aforesaid epitaxial wafer 300 that has reflective mirror of making is stacked and placed on the substrate bonding under nitrogen atmosphere in the upside-down mounting mode;
7) remove LED epitaxial slice 300 first conductivity type substrates 301, first conductivity type buffer layer 302 and the first conductivity type etch stop layer 303;
8) deposit pattern electrodes 517 on LED epitaxial slice 300 first conductivity type ohmic contact layers 304;
9) grinding and polishing attenuate substrate 400;
10) at substrate 400 bottom depositing metal electrodes 518;
11) the etching cleavage forms tube core.
After efficient full-bright all-reflection light-emitting-diode of the present utility model adopts above scheme, have following positive effect:
(1) can greatly promote and get optical efficiency.Efficient full-bright all-reflection light-emitting-diode of the present utility model, be the GaAs substrate epitaxial grow conventional P towards on LED epitaxial slice 300 bases on, made the structure (wavelength is had>90% reflectivity greater than the light of 590nm) of medium and metal reflective mirror, to replace the DBR reflective mirror of prior art, solved the band-limited problem in angle of DBR reflective mirror, when its upside-down mounting on substrate, the light that active area sends takes out from the first conductivity type ohmic contact layer, and reflective mirror can be the photon of downward propagation and the photon of the first conductivity type ohmic contact layer reflected back semi-conducting material inside provides comprehensive reflection, has improved luminous intensity greatly; Moreover having removed the GaAs substrate that absorbs photon, a large amount of photons have been avoided absorption, have further improved the extraction efficiency of light; Because of having adopted pattern electrodes on the first conductivity type ohmic contact layer, avoided the light-shading effect of front electrode pad again, increased and got light area, it is more even that electric current is injected, and gets optical efficiency and be greatly improved again.Comprehensive above factor has the AlGaInP red light-emitting diode that absorbs substrate with routine and compares, the getting optical efficiency and can improve 2~3 times of light-emitting diode of the present utility model; Have the AlGaInP red light-emitting diode that absorbs substrate and dbr structure with routine and compare, the getting optical efficiency and can improve 1~2 times of light-emitting diode of the present utility model.Concerning the chip (620nm) of 300 * 300 μ m of the present utility model, the 20mA forward current injects down, and luminous intensity can reach 160mcd.
(2) can increase optical output power, reduce thermal resistance and cost, improve device reliability.Efficient full-bright all-reflection light-emitting-diode of the present utility model has increased under the first conductivity type current extension layer, has optimized electrode pattern, makes the electric current of light-emitting diode inject even, luminous even, heating reduction, improves luminous intensity, increases optical output power; Again because of adopting inverted structure; light-emitting diode can directly pass through the metal welding bed of material and substrate contacts, because of the metal welding bed of material is the good conductor of heat, very high thermal conductivity is arranged; and substrate also can adopt the high material of thermal conductivity; so can reduce thermal resistance, under the situation that high current density injects, work, improve device reliability; further improve the luminous efficiency of light-emitting diode; can realize the high-power output of light, reduce cost, be of value to large-scale production.
Below in conjunction with drawings and Examples the utility model is described further.
Description of drawings
Fig. 1: existing conventional AlGaInP Multiple Quantum Well (MQW) light-emitting diode cross-sectional view;
Fig. 2: existing AlGaInP Multiple Quantum Well (MQW) the light-emitting diode cross-sectional view that has DBR;
Fig. 3: the utility model efficient full-bright all-reflection light-emitting-diode epitaxial wafer 300 structure charts;
Fig. 4: the utility model efficient full-bright all-reflection light-emitting-diode substrate 400 schematic diagrames;
Fig. 5: the utility model first preferred embodiment light-emitting diode 500 schematic cross-sections;
Fig. 6: the utility model second preferred embodiment light-emitting diode 600 schematic cross-sections;
Fig. 7: the utility model the 3rd preferred embodiment light-emitting diode 700 schematic cross-sections;
Among the figure: 101 is the n-GaAs substrate, and 102 is the n-GaAs resilient coating, and 103 is n-AlInP lower limit layer (n-cladding layer), and 104 is the (Al of non-doping 0.15Ga 0.85) 0.5In 0.5P MQW active area, 105 is p-AlInP upper limiting layer (p-cladding layer), and 106 is p type ohmic contact layer, and 107 is upper surface electrode, and 108 is the base plane Metal Contact;
201 is the n-GaAs substrate, and 202 is the n-GaAs resilient coating, and 203 is DBR, and 204 is n-AlInP lower limit layer (n-cladding layer), and 205 is the (Al of non-doping 0.15Ga 0.85) 0.5In 0.5P MQW active area, 206 is p-AlInP upper limiting layer (p-cladding layer), and 207 is the p-current extending, and 208 is p type ohmic contact layer, and 209 is upper surface electrode, 210 is the base plane Metal Contact;
301 is the first conductivity type substrate, 302 is first conductivity type buffer layer, 303 is the first conductivity type etch stop layer, 304 is the first conductivity type ohmic contact layer, and 305 is the first conductivity type current extension layer, and 306 is the first conductivity type lower limit layer, 307 is the active area of non-doping, 308 is the second conductivity type upper limiting layer, and 309 is the second conductivity type current extension layer, and 310 is the second conductivity type ohmic contact layer;
401 is the substrate substrate, and 402 is the barrier layer, and 505 is the metal welding bed of material;
515 is the non-conductive medium layer, and 506 is metal level, and 517 is pattern electrodes, and 518 is metal electrode;
615 is conducting medium layer tin indium oxide (ITO);
701 is sapphire (Al 2O 3), 718 for extending metal electrode.
Embodiment
Describe embodiment of the present utility model in detail below in conjunction with drawings and Examples.
Fig. 5 is the schematic cross-section of the efficient full-bright all-reflection light-emitting-diode 500 of the utility model first preferred embodiment.This efficient full-bright all-reflection light-emitting-diode structure 500 comprises the first conductivity type ohmic contact layer 304 successively, the first conductivity type current extension layer 305, the first conductivity type lower limit layer 306, the active area 307 of non-doping, the second conductivity type upper limiting layer 308, the second conductivity type current extension layer 309, the second conductivity type ohmic contact layer 310, non-conductive medium layer 515, metal level 506, the metal welding bed of material 505, substrate substrate (heavy doping N type single-sided polishing silicon single crystal) 401, barrier layer 402, pattern electrodes 517, metal electrode 518.Its manufacture method is:
1) with MOCVD epitaxial growth LED epitaxial slice 300;
2) with the PECVD growing technology on 300 second conductivity type ohmic contact layers the non-conductive transparent dielectric layer of deposit, as SiO 22000~4000 ;
3) use photoetching technique SiO 2Etch latticedly, erode the SiO at interface between nets place 2
4) vacuum thermal evaporation metal level such as AuZnAu, metal level passes through SiO 2The conductive path at grid place and the second conductivity type ohmic contact layer form ohmic contact;
5) use vacuum thermal evaporation at substrate substrate growth one deck barrier layer Ti;
6) sputter forms the metal welding bed of material such as gold-tin alloy on aforementioned barrier layer;
7) the aforesaid epitaxial wafer that has reflective mirror of making is stacked and placed on the aforementioned substrate of making in the upside-down mounting mode, puts into alloying furnace bonding under nitrogen atmosphere, 350~500 ℃ of bonding temperatures, 30 minutes time by the graphite anchor clamps;
8) mixed solution of 300 first conductivity type substrates 301, first conductivity type buffer layer 302 and the first conductivity type etch stop layer, 303 usefulness chemo-selective corrosive agent hydrogen peroxide and ammoniacal liquor is removed;
9) vacuum thermal evaporation pattern electrodes such as AuGeNi on aforementioned 300 first conductivity type ohmic contact layers 304;
10) grinding and polishing attenuate aforesaid base plate;
11) at aforesaid base plate bottom vacuum thermal evaporation metal electrode such as TiAu, aforementioned annular electrode and laminated metal electrode are positioned at the substrate both sides, form vertical electrode up and down;
12) the etching cleavage forms the tube core of 300 * 300 μ m;
By 300 * 300 μ m chips (620nm) that present embodiment is made, brightness is 160mcd when 20mA, and peak power efficient can reach 21%, forward voltage V fLess than 2.1V.
Fig. 6 is the schematic cross-section of the efficient full-bright all-reflection light-emitting-diode 600 of the utility model second preferred embodiment.The structure with efficient full-bright all-reflection light-emitting-diode 500 is identical with each layer material haply with each layer material system for the structure of efficient full-bright all-reflection light-emitting-diode 600, but the dielectric mirror in the reflective mirror system replaces non-conductive medium layer SiO with conducting medium layer tin indium oxide (ITO) 615 2515; Manufacture method is also basic identical, but saves the technology of a step photoetching grid.The chip (620nm) of 300 * 300 μ m of present embodiment, 20mA forward current inject down, and luminous intensity can reach 165mcd.
Fig. 7 is the schematic cross-section of the efficient full-bright all-reflection light-emitting-diode 700 of the utility model the 3rd preferred embodiment.The structure with efficient full-bright all-reflection AlGaInP red light-emitting diode 500 is identical with each layer material haply with each layer material system for the structure of efficient full-bright all-reflection light-emitting-diode 700, but the substrate substrate is with being sapphire (Al 2O 3) 701 replace heavy doping N type single-sided polishing silicon 401 monocrystalline, because of sapphire is an insulating material, so with extending metal electrode 718 replacement metal electrodes 518, and extension electrode 718 and pattern electrodes 517 are positioned at substrate the same side; Manufacture method is basic identical.The chip (620nm) of 300 * 300 μ m of present embodiment, 20mA forward current inject down, and luminous intensity can reach 145mcd.
The above is a specific embodiment of the utility model only, is not in order to limiting protection range of the present utility model, and all other do not break away from various remodeling and the modification of being carried out in the utility model scope, all should be included in the scope of claims.

Claims (3)

1. efficient full-bright all-reflection light-emitting-diode, it is characterized in that: comprise pattern electrodes (517) successively, the first conductivity type ohmic contact layer (304), the first conductivity type current extension layer (305), the first conductivity type lower limit layer (306), the active area of non-doping (307), the second conductivity type upper limiting layer (308), the second conductivity type current extension layer (309), the second conductivity type ohmic contact layer (310), dielectric layer, metal level (506), the metal welding bed of material (505), barrier layer (402), substrate substrate (401), metal electrode (518);
Wherein dielectric layer and metal level (506) are united as reflective mirror; Substrate substrate (401), barrier layer (402) and the metal welding bed of material (505) composing base (400).
2. efficient full-bright all-reflection light-emitting-diode according to claim 1 is characterized in that: described pattern electrodes (517) is annular, back-shaped, slotting finger-type, star, M shape.
3. a kind of efficient full-bright all-reflection light-emitting-diode according to claim 1 is characterized in that: described dielectric layer is non-conductive transparent dielectric layer (515), or dielectric layer is conductive, transparent dielectric layer (615).
CNU200620116351XU 2006-05-26 2006-05-26 High efficience high brightness reflecting LED Expired - Lifetime CN2909538Y (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104347765A (en) * 2013-08-06 2015-02-11 上海蓝光科技有限公司 Light-emitting diode and manufacturing method thereof
CN105006506A (en) * 2014-04-16 2015-10-28 晶元光电股份有限公司 Luminescence apparatus
CN107482098A (en) * 2017-09-20 2017-12-15 南昌大学 A kind of film LED chip structure
CN107958945A (en) * 2017-11-20 2018-04-24 扬州乾照光电有限公司 A kind of upside-down mounting LED chip of no deielectric-coating and preparation method thereof

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104347765A (en) * 2013-08-06 2015-02-11 上海蓝光科技有限公司 Light-emitting diode and manufacturing method thereof
CN105006506A (en) * 2014-04-16 2015-10-28 晶元光电股份有限公司 Luminescence apparatus
CN107482098A (en) * 2017-09-20 2017-12-15 南昌大学 A kind of film LED chip structure
CN107482098B (en) * 2017-09-20 2023-05-09 南昌大学 Thin film LED chip structure
CN107958945A (en) * 2017-11-20 2018-04-24 扬州乾照光电有限公司 A kind of upside-down mounting LED chip of no deielectric-coating and preparation method thereof

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Owner name: BEIJING TAISHIXINGUANG SCIENCE CO., LTD.

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Effective date: 20081017

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Address after: Branch of Beijing Economic Development Zone, two Beijing street, No. 4, building 2, 1-4 layers south, zip code: 100176

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Address before: No. 100 Ping Park, Beijing, Chaoyang District: 100022

Patentee before: Beijing University of Technology

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Address after: 100176, No. 1, Ze Bei street, Beijing Economic Development Zone, Beijing

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Address before: Branch of Beijing Economic Development Zone Beijing city two street 100176 No. 4 Building 2 layer in the south of 1-4

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