CN103872208A - Light emitting diode of vertical structure of reflector with high reflectivity - Google Patents
Light emitting diode of vertical structure of reflector with high reflectivity Download PDFInfo
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- CN103872208A CN103872208A CN201410114252.7A CN201410114252A CN103872208A CN 103872208 A CN103872208 A CN 103872208A CN 201410114252 A CN201410114252 A CN 201410114252A CN 103872208 A CN103872208 A CN 103872208A
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- 238000002310 reflectometry Methods 0.000 title claims abstract description 37
- 239000002131 composite material Substances 0.000 claims abstract description 37
- 239000000758 substrate Substances 0.000 claims abstract description 17
- 239000000463 material Substances 0.000 claims abstract description 5
- 229910000679 solder Inorganic materials 0.000 claims description 7
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 6
- 238000000605 extraction Methods 0.000 abstract description 10
- 230000031700 light absorption Effects 0.000 abstract description 4
- 238000003466 welding Methods 0.000 abstract description 4
- 238000000034 method Methods 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 206010040844 Skin exfoliation Diseases 0.000 description 2
- 230000035618 desquamation Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000001259 photo etching Methods 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 238000013517 stratification Methods 0.000 description 2
- 229910017750 AgSn Inorganic materials 0.000 description 1
- 241001025261 Neoraja caerulea Species 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
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- 230000000737 periodic effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/44—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the coatings, e.g. passivation layer or anti-reflective coating
- H01L33/46—Reflective coating, e.g. dielectric Bragg reflector
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
- H01L2933/0008—Processes
- H01L2933/0025—Processes relating to coatings
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Abstract
The invention discloses a light emitting diode of a vertical structure of a reflector with the high reflectivity. The light emitting diode of the vertical structure of the reflector with the high reflectivity sequentially comprises an electric conduction substrate, an electric conduction welding layer, a P-type layer, a light emitting layer, an N-type layer and an N electrode from bottom to top, wherein the N-type layer is provided with a roughened surface. The light emitting diode of the vertical structure of the reflector with the high reflectivity is characterized in that a composite reflector composed of an Ag-based reflector and dielectric reflectors with the lower reflectivity is arranged between the electric conduction welding layer and the P-type layer; the multiple dielectric reflectors with the lower reflectivity are evenly distributed on the upper surface of the Ag-based reflector; the superficial area occupied by the dielectric reflectors with the lower reflectivity is 20-80% of the superficial area of the composite reflector; the P-type layer, the light emitting layer and the N-type layer can be one of an AlGaInN-based material system and an AlGaInP-based material system. The physical phenomenon that visible light is totally emitted when entering the media with the lower reflectivity from the media with the high reflectivity is utilized ingeniously, absorption of light on the interface of the reflector is reduced, the effective reflectivity of the composite reflector is improved, and therefore the light extraction efficiency of an LED structure is improved.
Description
Technical field
The present invention relates to light emitting semiconductor device, especially relate to a kind of light emitting diode with vertical structure with high reflectivity mirror.
Background technology
In recent years, due to the significantly lifting of GaN base blue LED (LED) efficiency and the application in synthesize white light (blue-ray LED+yellow fluorescent powder), make LED light source become green illumination light source of new generation.Also make the application of LED from fields such as early stage video picture demonstrations, be extended to gradually general illumination field.In order to obtain higher light extraction efficiency (needs of energy-conserving and environment-protective), conventionally need to be by the primary substrate desquamation of LED film, and LED film transfer is made to light emitting diode (LED) chip with vertical structure to new supporting substrate, and be equipped with speculum and the coarse surface of high reflectance.The ruddiness of at present efficient InGaN base blue green light and AlGaInP base, all adopts this structure.
Because Ag is the highest to the reflectivity of visible ray, the conventional speculum of LED chip of vertical stratification is Ag or Ag base alloy at present, and the LED structure of vertical stratification as shown in Figure 1.The light sending from luminescent layer 105 need to be through repeatedly could be from the coarse surface outgoing of N-type layer 106 in Ag base reflecting mirror 103 reflection, and Ag base reflecting mirror 103 only has 90-93% to the reflectivity of visible ray, the light that Ag base reflecting mirror 103 can send luminescent layer 105 like this has obvious absorption, causes light extraction efficiency to decline.By way of example, suppose light that LED luminescent layer 105 sends on average will through 3 times could outgoing from LED film in 103 reflections of Ag base reflecting mirror, the reflectivity of getting Ag base reflecting mirror 103 is 93%, light loss ratio is 1-0.93 × 0.93 × 0.93=19.6%.Therefore, Ag base reflecting mirror 103 is difficult to light extraction efficiency to do very highly.In order to obtain higher light extraction efficiency, must further promote the reflectivity of speculum.
summary of the invention:
The object of the present invention is to provide a kind of light emitting diode with vertical structure with high reflectivity mirror, this light emitting diode with vertical structure adopts the composite reflector with the reflectivity higher than common Ag base reflecting mirror, reduce the absorption of light at reflector interface, improve the effective reflectivity of composite reflector, thereby promoted the light extraction efficiency of LED structure.
The object of the present invention is achieved like this:
A kind of light emitting diode with vertical structure with high reflectivity mirror, comprise successively from bottom to up conductive substrates, conductive solder layer, P type layer, luminescent layer, the N-type layer with coarse surface, N electrode, feature is: between conductive solder layer and P type layer, be provided with the composite reflector being made up of Ag base reflecting mirror and low refractive index dielectric speculum, several low refractive index dielectric speculums are evenly arranged in the upper surface of Ag base reflecting mirror, and the shared surface area of low refractive index dielectric speculum accounts for the 20-80% of the surface area of composite reflector.
Preferably, the shared surface area of low refractive index dielectric speculum accounts for the 40-60% of the surface area of composite reflector.
The medium that forms low refractive index dielectric speculum is SiO
2, vacuum or airborne one.
P type layer, luminescent layer, the N-type layer with coarse surface are the one in AlGaInN base or AlGaInP base material system.
The present invention is the speculum that adopts a kind of brand new on the basis of conventional light emitting diode with vertical structure: the composite reflector being made up of Ag base reflecting mirror and low refractive index dielectric speculum, the composite reflector of high reflectivity mirror is by Ag base reflecting mirror and low refractive index dielectric (SiO
2, vacuum or air) space arrangement by a certain percentage forms.Fig. 2 has provided the light emitting diode (LED) chip with vertical structure schematic diagram with composite reflector.Composite reflector is compared Ag speculum and is had higher reflectivity, therefore can obtain higher light extraction efficiency.
Make a concrete analysis of below: the actual reflectance of composite reflector is the weighted average of Ag base reflecting mirror 203 partial reflectances and low refractive index dielectric speculum 208 partial reflectances.At this, applicant lifts GaN base LED and illustrates the reflection problems of composite reflector.Suppose that low refractive index dielectric speculum 208 is for vacuum (refractive index is 1), with the Area Ratio in Ag base reflector be 1:1, the probability that the light that LED active layer sends is reflected by Ag base reflecting mirror 203 and low refractive index dielectric speculum 208 is respectively 50%, and light is from P type layer 204(GaN) incide low refractive index dielectric speculum 208(vacuum) the critical angle θ of reflection total reflection is 23o.As shown in Figure 2, can be reflected by three kinds of modes from the light of luminescent layer 205 outgoing, be respectively shown in Fig. 2
,
with
.In mode
under situation, incide Ag base reflecting mirror 203 surfaces be reflected from the light of luminescent layer 205 outgoing, the reflectivity of this part equals the reflectivity of Ag base reflecting mirror 203, gets 93% at this; In mode
under situation, incide low refractive index dielectric speculum 208 surfaces from the light of luminescent layer 205 outgoing, incidence angle α is more than or equal to critical angle θ, there is full transmitting and by low refractive index dielectric speculum 208 in light now, because low refractive index dielectric speculum 208 does not absorb light, therefore the reflectivity of this part reflection is 100%; In mode
under situation, incide low refractive index dielectric speculum 208 surfaces from the light of luminescent layer 205 outgoing, incidence angle α is less than critical angle θ, now light incides on the Ag base reflecting mirror 203 of 208 belows, low-refraction reflector through low-refraction reflector 208, then reflected by Ag base reflecting mirror 203, the reflectivity of this part reflection equals the reflectivity of Ag base reflecting mirror 203, gets 93% at this.The reflectivity of composite reflector 200 is exactly
,
with
the weighted average of three kinds of reflection mode reflectivity.Obtain with the available following calculating of analysis according to hypothesis above.
Reflectivity=93% of composite reflector 200 × according to ratio+100% of mode I reflection × according to mode
ratio+93% × according to mode of reflection
the ratio of reflection.
Wherein, be to have made hypothesis before 50%(according to the ratio of mode I reflection), according to mode
it is the value of critical angle θ that the ratio of reflection equals 50% × (90-23)/90=37.2%(23), according to mode
the ratio of reflection equals 50% × 23/90=12.8%.
Therefore, reflectivity=93% × 50%+100% × 37.2%+93% × 12.8%=95.6% of composite reflector 200
This still suppose light that luminescent layer 205 sends on average will through 3 times could outgoing from LED film in composite reflector 200 reflections, now light loss ratio is 1-0.956 × 0.956 × 0.956=12.6%.
Known by above analysis, by using composite reflector to make light reflection loss ratio from using 19.6% of Ag base reflecting mirror to drop to 12.6%, this will obviously promote the light extraction efficiency of LED.
It is to be noted, can not increase by the mode of unlimited increase low refractive index dielectric speculum 208 ratios the reflectivity of composite reflector 200, because it is exactly the ohmic contact layer as P type layer 204 that composite reflector 200 also has a critical function, and low refractive index dielectric speculum 208 is non-conductive, cannot realize this function, can only lean on Ag base reflecting mirror 203 to realize.Therefore must ensure that Ag base reflecting mirror 203 accounts for certain proportion in composite reflector 200.
The present invention has utilized visible ray to incide this physical phenomenon of the full transmitting of low refractive index dielectric generation dexterously in high refractive index medium, reduce the absorption of light at reflector interface, improve the effective reflectivity of composite reflector, thereby promoted the light extraction efficiency of LED structure.
brief description of the drawings:
Fig. 1 is traditional light emitting diode (LED) chip with vertical structure structural representation only with single Ag base reflecting mirror, wherein: 101-conductive substrates, 102-conductive solder layer, 103-Ag base reflecting mirror, 104-P type layer, 105-luminescent layer, 106-there is the N-type layer of coarse surface, 107-N electrode;
Fig. 2 is the light emitting diode (LED) chip with vertical structure structural representation with composite reflector provided by the invention, wherein: 201-conductive substrates, 202-conductive solder layer, 203-Ag base reflecting mirror, 204-P type layer, 205-luminescent layer, 206-there is the N-type layer of coarse surface, 207-N electrode, 208-low refractive index dielectric speculum, the light sending from luminescent layer 205 incides the incidence angle of low refractive index dielectric speculum 208 to 200-composite reflector (being made up of Ag base reflecting mirror 203 and low refractive index dielectric speculum 208) α-, θ-light incides low refractive index dielectric speculum 208 and occurs the critical angle of total reflection from P type layer 204,
Fig. 3 is the vertical view of the composite reflector in Fig. 2.203-Ag base reflecting mirror, 208-low refractive index dielectric speculum, 200-composite reflector (being formed by Ag base reflecting mirror 203 and low refractive index dielectric speculum 208)
embodiment:
Below in conjunction with embodiment and contrast accompanying drawing the present invention will be described.
There is a vertical light-emitting diode structure for high reflectivity mirror, as shown in Figure 2.Comprise successively from bottom to up conductive substrates 201, conductive solder layer 202, the composite reflector 200 being formed by Ag base reflecting mirror 203 and low refractive index dielectric speculum 208, P type layer 204, luminescent layer 205, the N-type layer 206 with coarse surface and N electrode 207.Several low refractive index dielectric speculums 208 are evenly arranged in the upper surface of Ag base reflecting mirror 203, and the shared surface area of low refractive index dielectric speculum 208 accounts for the 20-80% of the surface area of composite reflector 200.
Preferably, the shared surface area of low refractive index dielectric speculum 208 accounts for the 40-60% of the surface area of composite reflector 200.
The medium that forms low refractive index dielectric speculum 208 is SiO
2, vacuum or airborne one.
P type layer 204, luminescent layer 205, the N-type layer 206 with coarse surface are the one in AlGaInN base or AlGaInP base material system.
Further illustrate the manufacture method of this structure below with GaN based vertical structure LED.In turn include the following steps:
A, LED film growth;
B, composite reflector are made;
C, film transfer and substrate desquamation;
D, coarse surface are made;
E, N electrode fabrication.
Steps A, at primary Grown LED ray structure, starts to comprise successively resilient coating, N-type GaN layer, In from substrate
xga
(1-X)n/GaN multiple quantum well layer, P type GaN layer (P type GaN upward).Described primary substrate can be the one in sapphire, SiC or Si substrate.
Step B, P type GaN layer surface deposition one deck SiO of the LED lighting means first obtaining in steps A
2film, then utilizes the method for photoetching by SiO
2corrode into the figure of periodic arrangement, finally evaporate again one deck Ag speculum.What directly contact with P type GaN layer like this just becomes Ag and SiO
2periodic structure, formed composite reflector layer.
Step C on the basis of step B, evaporates weld metal on composite reflector, then carries out thermal compression welding with conductive substrates, and wherein in conductive substrates, also evaporation has weld metal.After welding, peel off primary substrate.So just LED film is transferred in new conductive substrates from primary substrate, thereby obtained N-type GaN structure upward.Described weld metal can be the one in Au, AuSn or AgSn.
Step D, carries out surface coarsening by the N-type GaN of the LED film after shifting.Described surface coarsening can obtain by the method for utilizing etching or chemical corrosion.Conventionally N-type GaN adopts KOH solution to carry out surface coarsening.
Step e, utilizes the method for photoetching to obtain N electrode on the N-type GaN surface of surface coarsening.Described N electrode can be the one of the N-type GaN Ohm contact electrodes such as Ti base, Al base and Cr base.
Complete above five steps and can obtain the vertical light-emitting diode structure with high reflectivity mirror as shown in Figure 2.
Above structure has utilized visible ray to incide SiO cleverly in GaN
2there is complete this physical phenomenon of transmitting in medium, has reduced the absorption of light at reflector interface, improved the effective reflectivity (concrete principle illustrates in background technology) of composite reflector, thereby promote the light extraction efficiency of LED structure.
Claims (4)
1. one kind has the light emitting diode with vertical structure of high reflectivity mirror, comprise successively from bottom to up conductive substrates, conductive solder layer, P type layer, luminescent layer, the N-type layer with coarse surface, N electrode, it is characterized in that: between conductive solder layer and P type layer, be provided with the composite reflector being formed by Ag base reflecting mirror and low refractive index dielectric speculum, several low refractive index dielectric speculums are evenly arranged in the upper surface of Ag base reflecting mirror, and the shared surface area of low refractive index dielectric speculum accounts for the 20-80% of the surface area of composite reflector.
2. light emitting diode with vertical structure according to claim 1, is characterized in that: the shared surface area of low refractive index dielectric speculum accounts for the 40-60% of the surface area of composite reflector.
3. light emitting diode with vertical structure according to claim 1, is characterized in that: the medium that forms low refractive index dielectric speculum is SiO
2, vacuum or airborne one.
4. light emitting diode with vertical structure according to claim 1, is characterized in that: P type layer, luminescent layer, the N-type layer with coarse surface are the one in AlGaInN base or AlGaInP base material system.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410114252.7A CN103872208A (en) | 2014-03-26 | 2014-03-26 | Light emitting diode of vertical structure of reflector with high reflectivity |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410114252.7A CN103872208A (en) | 2014-03-26 | 2014-03-26 | Light emitting diode of vertical structure of reflector with high reflectivity |
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| CN103872208A true CN103872208A (en) | 2014-06-18 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104134723A (en) * | 2014-08-08 | 2014-11-05 | 映瑞光电科技(上海)有限公司 | Vertical type LED chip structure and manufacturing method thereof |
| CN113066913A (en) * | 2021-06-03 | 2021-07-02 | 南昌凯迅光电有限公司 | N-surface light-emitting AlGaInPLED film chip and preparation method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102054917A (en) * | 2009-10-28 | 2011-05-11 | Lg伊诺特有限公司 | Light emitting device and light emitting device package |
| CN102214750A (en) * | 2011-04-26 | 2011-10-12 | 财团法人交大思源基金会 | Thin film light emitting diode of nano lateral growth epitaxy and its manufacturing method |
| KR101270056B1 (en) * | 2012-01-30 | 2013-05-31 | 한국광기술원 | Manufacturing method for structure of reflector and structure of reflector manufactured by the method, and light emitted diode adopting the same |
-
2014
- 2014-03-26 CN CN201410114252.7A patent/CN103872208A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102054917A (en) * | 2009-10-28 | 2011-05-11 | Lg伊诺特有限公司 | Light emitting device and light emitting device package |
| CN102214750A (en) * | 2011-04-26 | 2011-10-12 | 财团法人交大思源基金会 | Thin film light emitting diode of nano lateral growth epitaxy and its manufacturing method |
| KR101270056B1 (en) * | 2012-01-30 | 2013-05-31 | 한국광기술원 | Manufacturing method for structure of reflector and structure of reflector manufactured by the method, and light emitted diode adopting the same |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104134723A (en) * | 2014-08-08 | 2014-11-05 | 映瑞光电科技(上海)有限公司 | Vertical type LED chip structure and manufacturing method thereof |
| WO2016019860A1 (en) * | 2014-08-08 | 2016-02-11 | 映瑞光电科技(上海)有限公司 | Vertical led chip structure and manufacturing method therefor |
| GB2542542A (en) * | 2014-08-08 | 2017-03-22 | Enraytek Optoelectronics Co | Vertical LED chip structure and manufacturing method therefor |
| GB2542542B (en) * | 2014-08-08 | 2017-09-20 | Enraytek Optoelectronics Co | Vertical LED chip structure and manufacturing method therefor |
| CN113066913A (en) * | 2021-06-03 | 2021-07-02 | 南昌凯迅光电有限公司 | N-surface light-emitting AlGaInPLED film chip and preparation method thereof |
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Application publication date: 20140618 |