CN202996889U - Optimized LED graphical substrate and LED chip - Google Patents
Optimized LED graphical substrate and LED chip Download PDFInfo
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- CN202996889U CN202996889U CN 201220696530 CN201220696530U CN202996889U CN 202996889 U CN202996889 U CN 202996889U CN 201220696530 CN201220696530 CN 201220696530 CN 201220696530 U CN201220696530 U CN 201220696530U CN 202996889 U CN202996889 U CN 202996889U
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- substrate
- led chip
- led
- hexagonal pyramid
- positive hexagonal
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Abstract
The utility model discloses an optimized LED chip graphical substrate. The pattern of the substrate is composed of a plurality of identically-structured regular hexagonal pyramids distributed on the surface of the substrate, wherein the dip angle alpha of each regular hexagonal pyramid is 55-60 degrees, and the edge distance d between every two adjacent regular hexagonal pyramids is 1.0-1.2 mum. Compared with the prior art, an LED chip containing the optimized LED chip graphical substrate has higher light output efficiency than an LED chip with an ordinary substrate, available effective light is greatly increased, the external quantum efficiency of the LED chip is increased, the regular hexagonal pyramid graph conforms to the lattice structure of GaN, the epitaxial growth of high-quality GaN crystals can be facilitated, the epitaxial quality is further improved, and the internal quantum efficiency of the LED chip is increased.
Description
Technical field
The utility model relates to LED chip, particularly a kind of LED patterned substrate and LED chip of optimization.
Background technology
The light extraction efficiency of LED depends on internal quantum efficiency and external quantum efficiency.On the one hand, because there is larger difference in lattice constant and the thermal coefficient of expansion of GaN and Sapphire Substrate, having produced density in the crystal of GaN film is 10
9-10
12cm
-2Pass through dislocation, this internal quantum efficiency to GaN base LED has produced adverse influence.Yet along with continuing to optimize of GaN growth technology, the crystalloid amount of heap of stone of GaN increases, and the internal quantum efficiency of LED reaches more than 90% at present.On the other hand, GaN has higher refraction coefficient (n=2.45), the critical angle [θ of beam projecting
c=sin
-1(n
air/ n
GaN)] be only 24.6 °, cause existing between LED chip and air serious total reflection phenomenon, external quantum efficiency is difficult to improve.The improvement scheme that proposed for this problem afterwards as introducing Bragg reflecting layer, photonic crystal, surface coarsening etc., has all improved the external quantum efficiency of LED to a certain extent.And the patterned substrate technology that developed recently gets up can not only change light by the pattern inclined plane and inject direction, and light is diminished (less than the cirtical angle of total reflection) in the incidence angle of interface outgoing, more light transmissives and going out, thus external quantum efficiency is improved; Can also make GaN produce brilliant effect laterally of heap of stone when epitaxial growth, thereby reduce defect concentrations in crystals, improve the internal quantum efficiency of LED.For satisfying the requirement of device performance, the design of graph substrate is several kinds of renewals, and from initial flute profile to hexagon, taper, prismoid shaped etc., the effect of patterned substrate technology is approved.
The pattern of substrate is the key of patterned substrate technology, and underlay pattern develops so far, and LED light extraction effect and epitaxial quality are improved significantly, has become the important channel of improving the LED performance, and the light extraction efficiency of LED is played decisive role.As the direct factor that affects light path, the parameter of pattern will certainly affect (comprising the length of side, height and spacing etc.) performance of LED in the choice.The people such as J.H.Cheng utilize wet etching technique to etch the cone shaped pattern with different inclination angle on Sapphire Substrate, find that the inclination angle of cone shaped pattern produces considerable influence to the crystalloid amount of heap of stone of GaN, defect concentration, internal quantum efficiency etc.In order to reduce dislocation, should take less laterally inclined angle, but small inclination can weaken figure to reflection of light or scattering effect, therefore need to seek a balance point.It is 3 μ m that the people such as D.S.Wuu utilize wet etching technique to prepare the length of side on Sapphire Substrate, the degree of depth is the triangular pyramid figure of 1.5 μ m, adopt the mocvd method growing GaN and make chip, it is carried out optic test, the external quantum efficiency of finding the graphical sapphire substrate GaN-based LED is different because of the change of pattern density, and the power output of patterned substrate LED promotes 25% than the power output of common LED.In addition, the human nanometer embossings such as R.Hsueh prepare nano level underlay pattern on Sapphire Substrate, the light intensity of the LED chip that this substrate produces and light emission rate have improved respectively 67% and 38% all higher than common Sapphire Substrate LED, also are better than micron order graph substrate LED.But be not that dimension of picture is less, the performance of LED is just better, and the relation between dimension of picture and LED performance still needs balance.Studies show that: along with reducing of pattern-pitch, be prone at GaN and sapphire interface the cavity that has little time to heal and produce due to the GaN growth, and cause the more dislocation of epitaxial loayer, even if light extraction efficiency promotes to some extent, but the increase of epitaxial loayer dislocation can reduce its internal quantum efficiency and LED chip life-span.In addition, the nano-scale patterns manufacturing cost is high, and industrialization is more difficult, has also greatly limited it and has applied.This shows, the optimization of dimension of picture and LED performance also needs further research.
Even if patterned substrate has increased substantially the light extraction efficiency of LED, but at present still rare about the research of positive hexagonal pyramid figure, for the graph substrate take positive hexagonal pyramid as basic pattern, do not have yet achievement in research can explicitly point out the parameters such as its best pattern inclination angle, the length of side, pattern density, the application of positive hexagonal pyramid graph substrate pattern lacks the design objective of a cover system.In addition, on the optimization problem of pattern dimension, solve that size is dwindled and its balance between GaN growth quality is damaged, guarantee crystalloid amount better of heap of stone under the prerequisite that improves light extraction efficiency, accomplish raising LED aspect of performance truly, still require study.Therefore, the most optimized parameter of determining positive hexagonal pyramid patterned substrate pattern needs to be resolved hurrily.
The utility model content
For the above-mentioned shortcoming and deficiency that overcome prior art, the purpose of this utility model is to provide a kind of LED patterned substrate of optimization, has advantages of that light extraction efficiency is high.Another purpose of the present utility model is to provide the LED chip of the LED patterned substrate that comprises above-mentioned optimization.
The purpose of this utility model realizes by following scheme:
A kind of LED patterned substrate of optimization, the pattern of substrate is comprised of the identical positive hexagonal pyramid of a plurality of shapes that are arranged in substrate surface, and the inclination alpha of positive hexagonal pyramid is 55 ° ~ 60 °; The back gauge d of adjacent positive hexagonal pyramid is 1.0～1.2 μ m.
The positive hexagonal pyramid that described a plurality of shape is identical adopts the rectangular arranged mode.
The positive hexagonal pyramid that described a plurality of shape is identical adopts the hexagonal arrangement mode.
A kind of LED chip comprises the LED patterned substrate of above-mentioned optimization.
Compared with prior art, the utlity model has following advantage and beneficial effect:
(1) the utility model is by optimizing the pattern parameter of positive hexagonal pyramid patterned substrate, greatly improved the ability of reflection photon arrival LED chip top and bottom, more light reflections to chip pushes up, the bottom thereby make, greatly increased the effective sunlight that can be utilized fully, strengthen the light extraction efficiency of graphical sapphire substrate GaN base LED, thereby improve the external quantum efficiency of LED.Compare common pattern-free substrate LED, total light flux increases to 2.49 times, and the top light flux increases to 3.29 times, and the bottom light flux increases to 3.02 times.
(2) the utlity model has the light extraction efficiency more excellent than general substrate LED chip, and positive hexagonal pyramid figure meets the lattice structure of GaN crystal, be conducive to epitaxial growth high-quality GaN crystal.
(3) pattern parameter that adopt to optimize of the utility model is avoided the too large or too little of heap of stone brilliant defective that causes of Distances Between Neighboring Edge Points, has further improved crystalloid amount of heap of stone, thereby has improved the internal quantum efficiency of LED.
Description of drawings
Fig. 1 is the schematic diagram of the LED chip of embodiment 1.
Fig. 2 is the schematic diagram of patterned substrate of the LED chip of embodiment 1.
Fig. 3 is the monomer schematic diagram of the positive hexagonal pyramid figure that adopts of the patterned substrate of the LED chip of embodiment 1, and the parameter of positive hexagonal pyramid pattern comprises inclination alpha, high h and positive hexagonal pyramid length of side a.
Fig. 4 is the arrangement mode schematic diagram that the patterned substrate of the LED chip of embodiment 1 adopts.
Fig. 5 is that the total light flux of LED chip is with the changing trend diagram of the inclination alpha of positive hexagonal pyramid.
Fig. 6 is that the total light flux of LED chip is with the changing trend diagram of the length of side a of positive hexagonal pyramid.
Fig. 7 is that the total light flux of LED chip is with the changing trend diagram of positive hexagonal pyramid back gauge d.
Embodiment
Below in conjunction with embodiment and accompanying drawing, the utility model is described in further detail, but execution mode of the present utility model is not limited to this.
Fig. 1 is the schematic diagram of the LED chip of the present embodiment, as shown in Figure 1, by the patterned sapphire substrate 11 that is arranged in order, N-type GaN layer 12, MQW quantum well layer 13, P type GaN layer 14 forms.
As shown in Fig. 2 ~ 4, the patterned substrate of the LED chip of the present embodiment, the pattern of substrate is comprised of the identical positive hexagonal pyramid 15 of a plurality of shapes that are arranged in substrate surface, and the inclination alpha of each positive hexagonal pyramid is 60 °; The back gauge d of adjacent positive hexagonal pyramid is 1.0 μ m, and the back gauge of adjacent positive hexagonal pyramid is defined as the distance on adjacent facies basialis pyramidis summit; In the present embodiment, the length of side a of positive hexagonal pyramid is 1.6 μ m; The positive hexagonal pyramid that described a plurality of shape is identical adopts rectangular arranged mode as shown in Figure 4.
Embodiment 2
The patterned substrate of the LED chip of the present embodiment, the pattern of substrate is comprised of the identical positive hexagonal pyramid of a plurality of shapes that are arranged in substrate surface, and the inclination alpha of each hexagonal pyramid is 55 °; In the present embodiment, the length of side a of positive hexagonal pyramid is 2 μ m; The back gauge d of adjacent positive hexagonal pyramid is 1.2 μ m; The positive hexagonal pyramid that described a plurality of shape is identical adopts the hexagonal arrangement mode.
Test case:
Adopt optical analysis software TracePro to do simulation test to the patterned substrate of LED chip of the present utility model, the simulation test process is as follows:
(1) substrate builds: the modeling function that adopts TracePro to carry is realized the making of substrate, and substrate dimension is 600 μ m * 250 μ m * 100 μ m, is rectangular-shaped.
(2) positive hexagonal pyramid design producing: the Plotting Function of employing Solidworks is realized it is characterized in that the making of positive hexagonal pyramid pattern: the inclination alpha of positive hexagonal pyramid is 55 ° ~ 60 °; The back gauge d of adjacent positive hexagonal pyramid is 1.0 ~ 1.2 μ m, rectangular arranging.
(3) epitaxial loayer builds: the modeling function that adopts TracePro to carry is realized the making of N-type GaN layer, MQW quantum well layer, P type GaN layer, N-type GaN layer is of a size of 600 μ m * 250 μ m * 4 μ m, the MQW quantum well layer is of a size of 600 μ m * 250 μ m * 50nm, P type GaN layer is of a size of 600 μ m * 250 μ m * 3 μ m, all is rectangular-shaped.
(4) target surface builds: the modeling function that adopts TracePro to carry is realized the making of six layers of target surface, six layers of target surface are placed in respectively upper and lower, the front, rear, left and right direction of LED chip, upper and lower target surface is of a size of 600 μ m * 250 μ m * 3 μ m, forward and backward target surface (the long limit of chip relatively) is of a size of 600 μ m * 104.41 μ m * 3 μ m, and left and right target surface (minor face of chip relatively) is of a size of 250 μ m * 104.41 μ m * 3 μ m.
(5) N-type GaN layer and graph substrate contact-making surface corresponding pattern build: insert the patterned layer of Solidworks foundation on substrate layer, the difference of employing TracePro subtracts function and realizes that N-GaN layer corresponding pattern builds.
(6) setting parameter of each material layer: the refractive index of Sapphire Substrate is 1.67, and N-type GaN, MQW quantum well, P type GaN material refractive index are 2.45, four all for the light of 450nm, and temperature setting is set to 300K, does not consider to absorb the impact with extinction coefficient.
(7) the quantum well layer surface source of light is set: the quantum well layer upper and lower surface respectively arranges a surface source of light attribute, the emission form is luminous flux, and the rink corner is distributed as the luminous field pattern of Lambertian, and luminous flux is 5000a.u., several 3000 of total light, several 10 of minimum light.
(8) ray tracing: utilize the software subsidiary system that clears off, the LED chip model of above-mentioned structure is carried out ray tracing, obtain respectively the luminous flux data of top, bottom, side.
Test result is as shown in Fig. 5 ~ 7.
Fig. 5 is that (positive hexagonal pyramid length of side a is 2 μ m to LED chip, and back gauge is 6 μ m; The length of side is 2 μ m, and back gauge is 4 μ m; The length of side is 1.5 μ m, and back gauge is 4 μ m) total the logical inclination alpha changing trend diagram with positive hexagonal pyramid of light.In figure, curve tendency shows: the total light flux of positive hexagonal pyramid pattern substrate LED is with the increase at inclination angle, and is totally in rising trend, and occurs maximum when being 55 ~ 60 ° at the inclination angle.
Fig. 6 is that (just the hexagonal pyramid inclination angle is 60 ° to LED chip, back gauge is 1.0 μ m) total light flux with the changing trend diagram of positive hexagonal pyramid length of side a, show the increase along with the positive hexagonal pyramid length of side, the total light flux of positive hexagonal pyramid graph substrate LED first increases, totally be afterwards and reduce trend, and when the length of side was 1.6 μ m, total light flux had maximum 7399a.u..
Fig. 7 is that (the positive hexagonal pyramid length of side is 2.0 μ m to LED chip, the inclination angle is 60 °) total light flux with the changing trend diagram of positive hexagonal pyramid back gauge d, increase along with back gauge, the total light flux of LED chip constantly descends, back gauge between positive hexagonal pyramid pattern is less, and its total light flux is larger, and works as patterned sides apart from 1.0 ~ 1.2 μ m, the total light flux of LED chip reaches stable, illustrates that little back gauge is conducive to improve the light extraction efficiency of LED chip.
Above-described embodiment is the better execution mode of the utility model; but execution mode of the present utility model is not limited by the examples; other any do not deviate from change, the modification done under Spirit Essence of the present utility model and principle, substitutes, combination, simplify; all should be the substitute mode of equivalence, within being included in protection range of the present utility model.
Claims (4)
1. the LED patterned substrate of an optimization, is characterized in that, the pattern of substrate is comprised of the identical positive hexagonal pyramid of a plurality of shapes that are arranged in substrate surface, and the inclination alpha of positive hexagonal pyramid is 55 ° 60 °; The back gauge d of adjacent positive hexagonal pyramid is 1.0 ~ 1.2 μ m.
2. the LED patterned substrate of optimization according to claim 1, is characterized in that, the positive hexagonal pyramid that described a plurality of shapes are identical adopts the rectangular arranged mode.
3. the LED patterned substrate of optimization according to claim 1, is characterized in that, the positive hexagonal pyramid that described a plurality of shapes are identical adopts the hexagonal arrangement mode.
4. a LED chip, is characterized in that, comprises the LED patterned substrate as the described optimization of claim 1 ~ 3 any one.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220696530 CN202996889U (en) | 2012-12-15 | 2012-12-15 | Optimized LED graphical substrate and LED chip |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220696530 CN202996889U (en) | 2012-12-15 | 2012-12-15 | Optimized LED graphical substrate and LED chip |
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| Publication Number | Publication Date |
|---|---|
| CN202996889U true CN202996889U (en) | 2013-06-12 |
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|---|---|---|---|
| CN 201220696530 Expired - Lifetime CN202996889U (en) | 2012-12-15 | 2012-12-15 | Optimized LED graphical substrate and LED chip |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103035792A (en) * | 2012-12-15 | 2013-04-10 | 华南理工大学 | Optimized light-emitting diode (LED) chip patterned substrate and LED chip |
| CN104810443A (en) * | 2015-04-30 | 2015-07-29 | 华南理工大学 | Arc-shaped hexagram cone graphical LED substrate and LED chip |
-
2012
- 2012-12-15 CN CN 201220696530 patent/CN202996889U/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103035792A (en) * | 2012-12-15 | 2013-04-10 | 华南理工大学 | Optimized light-emitting diode (LED) chip patterned substrate and LED chip |
| CN104810443A (en) * | 2015-04-30 | 2015-07-29 | 华南理工大学 | Arc-shaped hexagram cone graphical LED substrate and LED chip |
| CN104810443B (en) * | 2015-04-30 | 2018-05-15 | 华南理工大学 | A kind of arc Magen David bores graphical LED substrate and LED chip |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130612 |
|
| CX01 | Expiry of patent term |