CN209822674U - Epitaxial structure capable of improving luminous efficiency under low current density - Google Patents
Epitaxial structure capable of improving luminous efficiency under low current density Download PDFInfo
- Publication number
- CN209822674U CN209822674U CN201920749003.3U CN201920749003U CN209822674U CN 209822674 U CN209822674 U CN 209822674U CN 201920749003 U CN201920749003 U CN 201920749003U CN 209822674 U CN209822674 U CN 209822674U
- Authority
- CN
- China
- Prior art keywords
- layer
- gan
- gan layer
- current
- epitaxial structure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Led Devices (AREA)
Abstract
The utility model discloses an epitaxial structure capable of improving luminous efficacy under low current density, which is used for blue light LED and comprises a first semiconductor layer, an active area and a second semiconductor layer which are arranged on a substrate in sequence; the active region comprises at least one barrier layer and at least one well layer which are arranged at intervals; the well layer comprises a first N-GaN layer, a current homogenization layer arranged on the first N-GaN layer and a second N-GaN layer arranged on the current homogenization layer; the current homogenization layer is formed by doping a high resistivity material in GaN. The utility model discloses a set up the well layer structure of N-GaN + electric current homogenization layer + N-GaN in the active area for LED epitaxial structure is under the undercurrent condition, effectively promotes the effect of blocking up of electric current, makes undercurrent can be among the well layer lateral expansion, has reinforceed the diffusion effect, thereby has reached the purpose that power is little, the light efficiency is high.
Description
Technical Field
The utility model relates to a light emitting diode technical field especially relates to a can promote luminous efficacy's epitaxial structure under low current density.
Background
Light emitting diode, abbreviated LED for english word, main meaning: compared with the traditional lighting device, the Light Emitting Diode has the advantages of long service life, high lighting effect, no radiation, low power consumption and environmental protection. At present, the LED is mainly used in the fields of display screens, indicator lamps, backlight sources and the like.
The energy saving of the LED is a great index, and in the US LM80 standard, a strict standard exists. However, under the low current driving of the LED, the current is concentrated in a part of the area, which results in the non-uniform distribution of the brightness, and the non-enhanced luminous efficacy, further affecting the industrial lighting application.
In view of the above problem, patent application 201410742580.1 proposes an LED chip, which has a transparent conductive layer and a plurality of concentric arc grooves arranged on the surface of the transparent conductive layer; and the arc groove takes the P-type electrode as a center, the closer to the P-type electrode, the larger the interval of the arc groove is, and the farther away from the P-type electrode, the smaller the interval of the arc groove is. The resistance of the transparent conducting layer is gradually increased through different spaced arc grooves, so that the current cannot be gathered in an area close to the N-type electrode when being transversely diffused in the transparent conducting layer, and the current congestion effect is reduced; therefore, the luminous efficiency of the LED chip under the action of small current is improved; however, the process for preparing the holes in the ITO layer is complex, has high requirements on the performance of the transparent conductive layer, and is not beneficial to popularization.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problem that a can promote luminous efficacy's epitaxial structure under low current density is provided, its availability factor that can promote the electric current guarantees that LED chip luminance is even, and the light efficiency is high.
The technical problem to be solved by the present invention is to provide a method for preparing the epitaxial structure capable of improving luminous efficacy at low current density, which is simple in process.
In order to solve the above technical problem, the present invention provides an epitaxial structure capable of improving luminous efficacy at low current density, which is used for a blue LED, and includes a first semiconductor layer, an active region and a second semiconductor layer sequentially disposed on a substrate; the active region comprises at least one barrier layer and at least one well layer which are arranged at intervals;
the well layer comprises a first N-GaN layer, a current homogenization layer arranged on the first N-GaN layer and a second N-GaN layer arranged on the current homogenization layer;
the current homogenization layer has a resistivity of > 2.4 x 10 by doping GaN with-6Omega cm high resistivity material.
As an improvement of the above technical solution, the high resistivity material is selected from one or more of Al, B, Mg, and silicon nitride;
the resistivity of the current homogenization layer is more than 109Ω·cm。
As an improvement of the technical scheme, the well layer comprises a first N-GaN layer, a current equalizing layer arranged on the first N-GaN layer, a U-GaN layer arranged on the current equalizing layer and a second N-GaN layer arranged on the U-GaN layer.
As an improvement of the technical scheme, the well layer comprises a first N-GaN layer, a second N-GaN layer, and at least one U-GaN layer and at least one current homogenization layer which are arranged between the first N-GaN layer and the second N-GaN layer at intervals.
As an improvement of the above technical solution, the content of the high resistivity material in the current equalizing layer is gradually changed from the first N-GaN layer to the second N-GaN layer;
the decreasing change is a continuous change, a gradient change, or a mixed gradient change.
As an improvement of the technical scheme, the content of the high-resistivity material in each barrier layer is gradually reduced from the first semiconductor layer to the second semiconductor layer;
the decreasing change is a continuous change, a gradient change, or a mixed gradient change.
As an improvement of the technical scheme, the current homogenization layer is an AlGaN layer, wherein the content of Al is less than or equal to 5 wt%.
As an improvement of the technical scheme, the resistivity of the N-GaN layer is less than or equal to 3 omega cm;
the resistivity of the U-GaN layer is 10000-50000 omega cm.
As an improvement of the technical scheme, the thickness of the first N-GaN layer and the second N-GaN layer isThe thickness of the U-GaN layer isThe thickness of the current homogenization layer is
As an improvement of the technical scheme, the thickness of the first N-GaN layer and the second N-GaN layer isThe thickness of the U-GaN layer isThe thickness of the current homogenization layer is
And 2-9U-GaN layers and 3-8 current equalization layers which are arranged at intervals between the first N-GaN layer and the second N-GaN layer.
Implement the utility model discloses, following beneficial effect has:
the utility model discloses a set up the well layer structure of N-GaN + electric current homogenization layer + N-GaN in the active area for LED epitaxial structure is under the undercurrent condition, effectively promotes the effect of blocking up of electric current, makes undercurrent can be among the well layer lateral expansion, has reinforceed the diffusion effect, thereby has reached the purpose that power is little, the light efficiency is high.
Drawings
Fig. 1 is a schematic structural diagram of an epitaxial structure of the present invention capable of improving light emitting efficiency under a low current density;
fig. 2 is a schematic structural view of a base layer in an embodiment of the present invention;
fig. 3 is a schematic view of a structure of a base layer in another embodiment of the present invention;
fig. 4 is a schematic view of a structure of a base layer in another embodiment of the present invention;
fig. 5 is a flow chart of a method for fabricating an epitaxial structure capable of increasing light emitting efficiency at low current density according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings. Only this statement, the utility model discloses the upper and lower, left and right, preceding, back, inside and outside etc. position words that appear or will appear in the text only use the utility model discloses an attached drawing is the benchmark, and it is not right the utility model discloses a concrete restriction.
Referring to fig. 1 and 2, the present invention discloses an epitaxial structure capable of improving luminous efficacy at low current density, which includes a substrate 1, a first semiconductor layer 2, an active region 3 and a second semiconductor layer 4 sequentially disposed on the substrate; the active region 3 includes at least one barrier layer 31 and at least one well layer 32 that are disposed at an interval. The barrier layer 31 comprises a first N-GaN layer 33, a circuit equalization layer 34 arranged on the first N-GaN layer 33 and a second N-GaN layer 35 arranged on the current equalization layer 34; wherein the current equalizing layer 34 is formed by doping a high resistivity material in GaN, and the current equalizing layer has a resistivity much greater than the first N-GaN layer and the second N-GaN layer. The utility model forms a high resistance value reinforced diffusion structure by arranging a well layer structure of N-GaN + current equalization layer + N-GaN in the active area and compounding the current equalization layer with high resistivity and the N-GaN layer with low resistance value; make and having the utility model discloses epitaxial structure's LED can effectively promote the effect of blocking up of undercurrent under the condition that uses the undercurrent for the undercurrent can be in the horizontal extension among the process, and the diffusion effect has been reinforceed in the dispersion distribution, thereby has reached the effect that power is little, the light efficiency is high.
Specifically, the low current density refers to a current lower than 500 mA; the high-resistivity material refers to the material with the conductivity of more than 2.4 multiplied by 10-6Omega cm. The utility model provides a high resistivity material chooses for use one or several kinds in Al, B, silicon nitride, through the doping of above-mentioned high resistivity material, makes the utility model provides a resistivity of current homogenization layer 34 > 109Omega cm, and the resistivity of the N-GaN layer is less than or equal to 3 omega cm; the large difference between the N-GaN layer 33/35 and the current equalization layer 34 results in energy level distortion, so that the overall resistance of the well layer is larger, and the current dispersion effect is better.
Preferably, the high-resistivity material is Al, and the resistivity of the AlGaN layer can be more than 1011Omega cm, and has better current dispersion effect. The Al doping process is simple, the doping temperature is less than 800 ℃, and the operation is easy; after doping, the Al content in the AlGaN layer is less than or equal to 5 wt%.
Further, referring to fig. 3, in an embodiment of the present invention, the barrier layer 31 includes a first N-GaN layer 33, a current equalization layer 34 disposed on the first N-GaN layer 33, a U-GaN layer 36 disposed on the current equalization layer 34, and a second N-GaN layer 35 disposed on the U-GaN layer 36. By growing the U-GaN layer 36 on the N-GaN layer 33/35 and then growing the current equalization layer 34, lattice mismatch can be effectively reduced, lattice holes are eliminated, and high luminous efficiency is guaranteed.
Specifically, in the embodiment, the thickness of the current equalization layer 34 is: thickness of U-GaN layer 36: N-GaN layer 33/35 thickness ═ 1-2: (2-5): (1-2), preferably (1.5-2): (4-5): 1; the barrier layer 31 structure within the thickness proportion range can better play the role of a current homogenization layer, so that the current dispersion effect is better under the condition of low current.
Specifically, the total thickness of the barrier layer 31 and the well layer 32 isWherein the first N-GaN layer 33 and the second N-GaN layer 35 have a thickness ofThe thickness of the U-GaN layer 36 isThe thickness of the current-equalizing layer 34 isPreferably, the first N-GaN layer 33 and the second N-GaN layer 35 have a thickness ofThe thickness of the U-GaN layer 36 isThe thickness of the current-equalizing layer 34 isOr the first N-GaN layer 33 and the second N-GaN layer 35 have a thickness ofThe thickness of the U-GaN layer 36 isThe thickness of the current-equalizing layer 34 is
Further, in order to enhance the optical efficiency of the epitaxial structure, in the present embodiment, the content of the high resistivity material in the current equalizing layer 34 is gradually decreased from the first N-GaN layer 33 to the second N-GaN layer 35; the degressive change is a continuous change, a gradient change or a mixed gradient change; the gradual change can effectively reduce the lattice mismatch between the current equalization layer 34 and the N-GaN layer 33/35, and improve the luminous efficiency of the LED. Specifically, the continuous variation means that the concentration of the high-resistivity material in the current uniformization layer 34 is continuously decreased from the first N-GaN layer 33 to the second N-GaN layer 34. The gradient means that the concentration of the high resistivity material is changed stepwise from the first N-GaN layer 33 to the second N-GaN layer 34, i.e., it is maintained constant in a first thickness range and is reduced to another constant concentration in a next thickness range. The mixed gradient change refers to the fusion of the two.
Alternatively, the content of the high resistivity material in each barrier layer 31 is gradually decreased from the first semiconductor layer 2 to the second semiconductor layer 3. The gradual change can effectively reduce lattice adaptation between the current homogenization layer and the N-GaN layer, and simultaneously can form a gradient diffusion structure in the small current transmission process, so that the small current is gradually diffused among different barrier layers through multi-layer induction, and the current is more favorably fully dispersed.
Referring to fig. 4, in another embodiment of the present invention, the barrier layer 31 includes a first N-GaN layer 33, a second N-GaN layer 35, and at least one U-GaN layer 36 and at least one current equalization layer 34 disposed therebetween and spaced apart from each other. The circulating structure of the U-GaN layer and the current homogenization layer is beneficial to forming a gradient diffusion structure, so that the current is gradually diffused among different current homogenization layers, and further the current is fully diffused among one barrier layer, and the effect of low current and high light efficiency is achieved.
Specifically, in the present embodiment, 2 to 9U-GaN layers 36 and 2 to 9 current equalizing layers are provided between the N-GaN layers 33/35, but not limited thereto. The resistivity of the U-GaN layer is 10000-50000 omega cm.
It should be noted that in some LED products, the chip purity needs to be high, i.e. the number of quantum wells needs to be reduced to the maximum, but at the same time, the LED chip is required to have high luminous efficiency, which puts higher demands on the current diffusivity in the barrier layer. Adopt the utility model provides a U-GaN layer and the endless barrier layer structure of electric current homogenization layer can satisfy above-mentioned user demand, the figure of the at utmost reduction quantum well.
Specifically, in the embodiment, the thickness of the current equalization layer 34 is: U-GaN layer 36 thickness ═ (1.5-3): 1; the circulating structure with the thickness proportion has the best current dispersion effect. Meanwhile, the tunneling of the well layer can be effectively avoided.
Specifically, in the present embodiment,the total thickness of the barrier layer 31 and the well layer 32 isWherein the first N-GaN layer 33 and the second N-GaN layer 35 have a thickness ofThe thickness of the U-GaN layer 36 isThe current-equalizing layer 34 has a thickness ofPreferably, the first N-GaN layer 33 and the second N-GaN layer 35 have a thickness ofThe thickness of the U-GaN layer 36 isThe current-equalizing layer 34 has a thickness of
Further, in order to give full play to the effect of the epitaxial structure in the present invention, the epitaxial structure further comprises a stress buffer layer 5 disposed between the first semiconductor layer 2 and the active region 3, and a buffer layer 6 and a U-GaN layer 7 disposed between the substrate 1 and the first semiconductor layer.
The light efficiency of the LED chip adopting the middle epitaxial structure of the utility model is tested; the effects are as follows:
it can be seen that the utility model provides an epitaxial structure has obvious promotion effect to blue light LED luminous efficiency under the undercurrent condition, especially to the product that electric current area is less, and the light efficiency hoisting rate is more obvious.
Correspondingly, referring to fig. 5, the present invention also discloses a method for preparing the above epitaxial structure, which includes:
s1: providing a substrate;
the substrate may be sapphire, but is not limited thereto;
s2: forming a first semiconductor layer on the substrate;
specifically, S2 includes:
s21: growing a buffer layer on the substrate;
s22: growing a U-GaN layer on the substrate;
s23: growing a first semiconductor layer on the U-GaN layer;
the first semiconductor layer is an N-GaN layer, but is not limited thereto.
S3: growing barrier layers and well layers in a plurality of periods on the first semiconductor layer to form an active region;
specifically, S3 includes:
s31: growing a stress buffer layer (SL-layer) on the first semiconductor layer;
s32: growing barrier layers and well layers for a plurality of periods on the stress buffer layer to form an active region;
specifically, a metal organic compound chemical vapor deposition Method (MOCVD) or a molecular beam epitaxy technology (MBE) is adopted to grow an active region;
wherein the growth temperature of the current equalization layer in the barrier layer is 500-800 ℃, and the growth pressure is 200-550 torr.
S4: growing a second semiconductor layer on the active region to obtain the epitaxial structure finished product;
the foregoing is a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements and decorations can be made without departing from the principle of the present invention, and these improvements and decorations are also considered as the protection scope of the present invention.
Claims (10)
1. An epitaxial structure capable of improving luminous efficiency under low current density is used for a blue light LED and comprises a first semiconductor layer, an active region and a second semiconductor layer which are sequentially arranged on a substrate; the active region comprises at least one barrier layer and at least one well layer which are arranged at intervals;
the well layer comprises a first N-GaN layer, a current homogenization layer arranged on the first N-GaN layer and a second N-GaN layer arranged on the current homogenization layer;
the current homogenization layer has a resistivity of > 2.4 x 10 by doping GaN with-6Omega cm high resistivity material.
2. The epitaxial structure of claim 1, wherein the high resistivity material is selected from one or more of Al, B, Mg, silicon nitride;
the resistivity of the current homogenization layer is more than 109Ω·cm。
3. The epitaxial structure of claim 1, wherein the well layer comprises a first N-GaN layer, a current-equalizing layer disposed on the first N-GaN layer, a U-GaN layer disposed on the current-equalizing layer, and a second N-GaN layer disposed on the U-GaN layer.
4. The epitaxial structure of claim 3, wherein the well layer comprises a first N-GaN layer, a second N-GaN layer, and at least one current-equalizing layer and at least one U-GaN layer spaced apart from each other between the first N-GaN layer and the second N-GaN layer.
5. The epitaxial structure of claim 3, wherein the concentration of the high resistivity material in the current-equalizing layer varies in a decreasing manner from the first N-GaN layer to the second N-GaN layer;
the decreasing change is a continuous change, a gradient change, or a mixed gradient change.
6. The epitaxial structure of claim 3, wherein the amount of high resistivity material in each barrier layer varies progressively from the first semiconductor layer to the second semiconductor layer;
the decreasing change is a continuous change, a gradient change, or a mixed gradient change.
7. The epitaxial structure of any of claims 3-6, wherein the current-equalizing layer is an AlGaN layer with Al content ≤ 5 wt%.
8. The epitaxial structure of claim 7, wherein the resistivity of the N-GaN layer is 3 Ω -cm or less;
the resistivity of the U-GaN layer is 10000-50000 omega cm.
9. The epitaxial structure of claim 3, wherein the first N-GaN layer and the second N-GaN layer have a thickness ofThe thickness of the U-GaN layer isThe thickness of the current homogenization layer is
10. The epitaxial structure of claim 4, wherein the first N-GaN layer and the second N-GaN layer have a thickness ofThe thickness of the U-GaN layer isThe thickness of the current homogenization layer is
And 2-9U-GaN layers and 3-8 current equalization layers which are arranged at intervals between the first N-GaN layer and the second N-GaN layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920749003.3U CN209822674U (en) | 2019-05-22 | 2019-05-22 | Epitaxial structure capable of improving luminous efficiency under low current density |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920749003.3U CN209822674U (en) | 2019-05-22 | 2019-05-22 | Epitaxial structure capable of improving luminous efficiency under low current density |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN209822674U true CN209822674U (en) | 2019-12-20 |
Family
ID=68883866
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201920749003.3U Active CN209822674U (en) | 2019-05-22 | 2019-05-22 | Epitaxial structure capable of improving luminous efficiency under low current density |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN209822674U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110137326A (en) * | 2019-05-22 | 2019-08-16 | 佛山市国星半导体技术有限公司 | A kind of epitaxial structure and preparation method thereof that luminous efficacy can be promoted under low current density |
| CN111987198A (en) * | 2020-08-31 | 2020-11-24 | 西安电子科技大学 | GaN-based transverse structure light-emitting diode based on Fe doping and manufacturing method |
-
2019
- 2019-05-22 CN CN201920749003.3U patent/CN209822674U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110137326A (en) * | 2019-05-22 | 2019-08-16 | 佛山市国星半导体技术有限公司 | A kind of epitaxial structure and preparation method thereof that luminous efficacy can be promoted under low current density |
| CN111987198A (en) * | 2020-08-31 | 2020-11-24 | 西安电子科技大学 | GaN-based transverse structure light-emitting diode based on Fe doping and manufacturing method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103107255B (en) | A kind of LED growing method | |
| CN105679893B (en) | LED epitaxial slice production method and LED epitaxial slice | |
| US9768351B2 (en) | Optoelectronic semiconductor device with barrier layer | |
| CN103107256B (en) | A kind of LED | |
| CN104966769A (en) | Quantum dot LED with dual photonic crystal structure | |
| CN104465898B (en) | Growing method of light-emitting diode epitaxial wafer and light emitting diode epitaxial wafer | |
| CN104538517A (en) | LED epitaxial structure with n-type superlattice structure and growth method of LED epitaxial structure | |
| CN209822674U (en) | Epitaxial structure capable of improving luminous efficiency under low current density | |
| CN102185055A (en) | Light-emitting diode and manufacturing method thereof | |
| CN103413877A (en) | Method for growing quantum well stress release layer of epitaxial structure and epitaxial structure | |
| CN105098004A (en) | Growth method for light-emitting diode epitaxial wafer and epitaxial wafer | |
| WO2017185777A1 (en) | Algainp light emitting diode | |
| CN104795476A (en) | Epitaxial structure of gallium nitride LED | |
| CN104091871A (en) | Light-emitting diode epitaxial slice and manufacturing method thereof | |
| CN102142492B (en) | Multiple quantum well structure, manufacturing method thereof and light emitting diode | |
| CN110137326A (en) | A kind of epitaxial structure and preparation method thereof that luminous efficacy can be promoted under low current density | |
| CN105140357A (en) | Epitaxial wafer with high light-emitting efficiency quantum barrier and preparation method thereof | |
| WO2013066088A1 (en) | Transparent thin film, light-emitting device comprising same and method for manufacturing same | |
| CN103035790A (en) | Light emitting diode epitaxial wafer and preparation method thereof | |
| TW201405860A (en) | Multi-quantum well structure and light emitting diode | |
| CN105098005B (en) | LED outer layer growths method and gained LED epitaxial wafer and chip | |
| CN204577452U (en) | A kind of epitaxial structure of gallium nitride light-emitting diode | |
| CN102064255A (en) | LED (Light Emitting Diode) and manufacturing method thereof | |
| CN102185053A (en) | Light-emitting diode and manufacturing method thereof | |
| CN103311389A (en) | Light-emitting diode epitaxial wafer and manufacturing method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |