CN110034215B - Method for improving leakage yield of LED chip - Google Patents
Method for improving leakage yield of LED chip Download PDFInfo
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- CN110034215B CN110034215B CN201910312987.3A CN201910312987A CN110034215B CN 110034215 B CN110034215 B CN 110034215B CN 201910312987 A CN201910312987 A CN 201910312987A CN 110034215 B CN110034215 B CN 110034215B
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/005—Processes
- H01L33/0062—Processes for devices with an active region comprising only III-V compounds
- H01L33/0066—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/005—Processes
- H01L33/0062—Processes for devices with an active region comprising only III-V compounds
- H01L33/0075—Processes for devices with an active region comprising only III-V compounds comprising nitride compounds
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier 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 semiconductor bodies
- H01L33/14—Semiconductor devices with at least one potential-jump barrier or surface barrier 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 semiconductor bodies with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
- H01L33/145—Semiconductor devices with at least one potential-jump barrier or surface barrier 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 semiconductor bodies with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure with a current-blocking structure
Abstract
The invention discloses a method for improving the leakage yield of an LED chip, which comprises the following steps: providing a substrate, forming an epitaxial layer, performing MESA etching, coating a micro-gap permeation layer, depositing a passivation layer, annealing to enable the micro-gap permeation layer and the passivation layer to be mutually stacked to form a leakage blocking layer, cleaning and removing the leakage blocking layer on the surface of the second semiconductor layer to form an electrode, and obtaining a low leakage rate LED chip finished product. The invention also discloses the low-leakage-rate LED chip prepared by the method. According to the invention, the electric leakage blocking layer is arranged on the epitaxial layer, so that the problem of electric leakage on the surface of the LED chip caused by that ITO and electrode metal enter the epitaxial layer through epitaxial defects in the process of forming the transparent conductive layer and the electrode is effectively prevented.
Description
Technical Field
The invention relates to the technical field of light-emitting diodes, in particular to a method for improving the leakage yield of an LED chip.
Background
Light Emitting Diodes (LEDs) are solid-state semiconductor devices capable of converting electrical energy into visible light, and as lighting devices, have considerable advantages over conventional lighting devices, namely long lifetime, high light efficiency, no radiation, low power consumption, and environmental protection. At present, LEDs are mainly used in the fields of display screens, indicator lamps, backlights and the like. The poor leakage current can reduce the energy consumption of the chip, so that the operation temperature is increased to burn out the components, and therefore, how to improve the leakage current and the efficiency of the product is urgent.
The main cause of LED chip leakage is defects during the LED wafer epitaxy process. Specifically, in is required In a large amount during the process of forming the quantum well, and a V-shaped notch is formed on the surface of the epitaxial layer due to the lattice difference between In and Ga atoms; in the subsequent process of the LED chip, the transparent conductive layer and the electrode metal easily enter the gap in the evaporation process, so that the surface electric leakage problem is caused, and the overall yield of the LED chip is reduced.
Disclosure of Invention
The invention aims to solve the technical problem of providing a method for improving the leakage yield of an LED chip, which can effectively prevent electrode metal from entering the defect of an epitaxial layer to cause the surface leakage problem and improve the overall yield of the LED chip.
The invention also solves the technical problem of providing an LED chip with low leakage rate.
In order to solve the technical problems, the invention provides a method for improving the leakage yield of an LED chip, which comprises the following steps:
(1) Providing a substrate;
(2) Forming an epitaxial layer on the substrate, the epitaxial layer including a first semiconductor layer, an active layer, and a second semiconductor layer;
(3) Performing MESA etching on the epitaxial layer to expose the first semiconductor layer;
(4) Coating a micro-gap permeation layer on the second semiconductor layer;
(5) Depositing a passivation layer on the micro-gap permeation layer;
(6) Annealing is carried out after the deposition is finished, so that the micro-gap permeation layer and the passivation layer are mutually stacked to form a leakage barrier layer;
(7) Cleaning by adopting a cleaning agent; removing the leakage barrier layer on the surface of the second semiconductor layer;
(8) Forming a first electrode on the first semiconductor layer; forming a second electrode on the second semiconductor layer; and obtaining a low-leakage-rate LED chip finished product.
As an improvement of the technical scheme, the micro-gap permeable layer is made of one or more of methanol, ethanol, isopropanol and acetone;
in the step (2), a spin coater is adopted to coat a micro-gap permeation layer on the surface of the second semiconductor layer.
As an improvement of the technical proposal, the passivation layer is made of SiO 2 、SiN x 、Al 2 O 3 、TiO 2 、Ti 2 O 5 One or more of them;
in the step (3), the passivation layer is deposited by adopting a plasma chemical vapor deposition method, wherein the deposition temperature is 80-150 ℃.
As an improvement of the technical scheme, in the step (6), the annealing temperature is 100-550 ℃ and the annealing time is 0.3-1h.
As an improvement of the above technical solution, the step (7) includes:
(7.1) placing the annealed LED chips into a cleaning agent to be soaked for 5-10 minutes;
(7.2) rinsing with pure water and drying.
As an improvement of the technical scheme, the cleaning agent is a mixture of hydrofluoric acid, phosphoric acid and nonionic polyacrylamide.
As an improvement of the above technical solution, the passivation layer includes a first passivation layer and a second passivation layer;
the first passivation layer is made of HfO 2 、Al 2 O 3 One of them;
the second passivation layer is made of SiO 2 、TiO 2 Is made of one of the materials.
As an improvement of the above technical solution, the thickness ratio of the first passivation layer to the second passivation layer is 1: (2-100).
Correspondingly, the invention also provides a low leakage rate LED chip, which comprises:
the substrate is provided with a plurality of holes,
the epitaxial layer is arranged on the substrate and comprises a first semiconductor layer, an active layer and a second semiconductor layer;
a leakage blocking layer disposed in the second semiconductor layer;
a first electrode disposed on the first semiconductor layer; and
a second electrode disposed on the second semiconductor layer;
the leakage blocking layer comprises a micro-gap permeation layer and a passivation layer; and the micro-gap permeation layer and the passivation layer are mutually overlapped after an annealing process to form the electric leakage barrier layer.
As an improvement of the technical scheme, the micro-gap permeable layer is made of one or more of methanol, ethanol, isopropanol and acetone;
the passivation layer is made of SiO 2 、SiN x 、Al 2 O 3 、TiO 2 、Ti 2 O 5 One or more of the above materials.
The implementation of the invention has the following beneficial effects:
1. according to the invention, the electric leakage blocking layer is arranged on the epitaxial layer, so that the problem of electric leakage on the surface of the LED chip caused by that ITO and electrode metal enter the epitaxial layer through epitaxial defects in the process of forming the transparent conductive layer and the electrode is effectively prevented.
2. The leakage barrier layer is divided into a micro-gap permeation layer and a passivation layer, wherein the micro-gap permeation layer is made of small molecular organic matters and can be fully permeated; the passivation layer can further reduce the interface state; the two are tightly overlapped through an annealing process, so that gaps with various sizes in the epitaxial layer are fully filled, and surface leakage current is restrained.
Drawings
FIG. 1 is a flow chart of a method for improving the leakage yield of an LED chip;
FIG. 2 is a schematic diagram of a low leakage LED chip according to the present invention;
fig. 3 is a schematic structural diagram of the leakage blocking layer according to the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings, for the purpose of making the objects, technical solutions and advantages of the present invention more apparent. It is only stated that the terms of orientation such as up, down, left, right, front, back, inner, outer, etc. used in this document or the imminent present invention, are used only with reference to the drawings of the present invention, and are not meant to be limiting in any way.
Referring to fig. 1 and 2, the invention provides a method for improving the leakage yield of an LED chip, comprising the following steps:
s1: providing a substrate;
the substrate 1 can be sapphire;
s2: forming an epitaxial layer on the substrate;
specifically, an epitaxial layer is formed on the substrate by a chemical deposition (MOCVD) method.
The epitaxial layer 2 includes a first semiconductor layer 21, an active layer 22, and a second semiconductor layer 23; the first semiconductor layer 21 and the second semiconductor layer 23 are both gallium nitride-based semiconductor layers, and the active layer is a gallium nitride-based active layer; in addition, the materials of the first semiconductor layer 21, the second semiconductor layer 23, and the active layer 22 provided in the embodiments of the present application may be other materials, which is not particularly limited in this application.
S3: performing MESA etching on the epitaxial layer to expose the first semiconductor layer;
specifically, an ICP or RIE etching apparatus is used to etch the epitaxial layer 2 to form a first exposed region, and the first exposed region is etched to the first semiconductor layer.
S4: coating a micro-gap permeation layer on the second semiconductor layer;
specifically, a spin coater is used to coat a micro-gap permeation layer on the surface of the second semiconductor layer. The coating amount is 0.01-0.05mL/cm 2 。
The micro gap permeable layer is made of one or more of methanol, ethanol, isopropanol and acetone; the micro gap permeation layer 31 is made of small molecular carbon-containing organic matters, has small molecular weight and low boiling point, and can rapidly diffuse into the defects of the epitaxial layer at normal temperature to fill the defects. Preferably, the micro gap permeation layer 31 is made of isopropanol and/or acetone; the viscosity of the two substances is higher than that of ethanol and methanol, so that the two substances are easy to be uniformly dispersed in the LED chip; and the volatilization speed is slower than that of methanol and ethanol, and the volatilization speed is easy to control in the subsequent annealing process.
S5: depositing a passivation layer on the micro-gap permeation layer;
specifically, the passivation layer 32 is deposited by adopting a plasma chemical vapor deposition (MOCVD) method, and the deposition temperature is 80-150 ℃; further, the deposition temperature is 90-110 ℃.
Passivation layer 32 is made of SiO 2 、SiN x 、Al 2 O 3 、TiO 2 、Ti 2 O 5 One or more of them; preferably, the passivation layer is made of SiO 2 Or SiN x Is prepared. The passivation layer has a thickness of 2 to 300nm, preferably 50 to 300nm.
Further preferably, the passivation layer 32 includes a first passivation layer 33 and a second passivation layer 34, and the second passivation layer 34 is located on the first passivation layer 33; the first passivation layer 33 is made of HfO 2 、Al 2 O 3 One of them; the second passivation layer 34 is made of SiO 2 、TiO 2 Is made of one of the materials. Preferably, the first passivation layer 33 is made of HfO 2 Made of SiO, the second passivation layer 34 2 Is prepared. Wherein, the dielectric constant of the first passivation layer 33 is higher, and the insulating property is stronger; leakage current can be effectively reduced. Meanwhile, the polarity of the raw material of the first passivation layer is strong, so that the raw material of the micro gap permeation layer 31 can be better combined with the raw material of the micro gap permeation layer.
In order to further play a role in reducing leakage current, the thickness ratio of the first passivation layer to the second passivation layer is 1: (2-100); preferably, the thickness ratio of the first passivation layer to the second passivation layer is 1 (50 to 100), and more preferably 1:80 to 100. When the first passivation layer is too thin, the insulation function cannot be sufficiently exerted. When the first passivation layer is too thick, the insulation performance is better, but the cost is higher; meanwhile, more importantly, the liquid raw material of the micro-gap permeation layer is easy to volatilize in a large amount through the first passivation layer, and the micro-gap filling effect is poor.
S6: annealing to enable the micro-gap permeation layer and the passivation layer to be mutually stacked to form a leakage barrier layer;
wherein the annealing temperature is 100-550 ℃, the annealing time is 0.3-1h, and the annealing temperature is 200-400 ℃ preferably. And annealing the raw material of the part of the micro-gap permeation layer which can be vaporized, so that the raw material is fully fused with the passivation layer, and stacking. Meanwhile, the passivation layer raw material can be changed into oxide or peroxide solid state, so that electric leakage is prevented.
It should be noted that: the prior art generally adopts SiO 2 、SiN x Or Al 2 O 3 The epitaxial layer is passivated once, but the particle size of the passivation layer is larger and the defect of the epitaxial layer cannot be completely filled by the passivation layer, so that the problem of higher leakage rate still exists. Therefore, the invention adopts liquid to carry out first filling, and mainly completes micro gap filling; then the passivation layer is adopted for secondary filling, mainly forThe middle and upper layer parts of the V-shaped notch; and the micro gap filling layer and the passivation layer are mutually stacked through an annealing process to form a leakage blocking layer with good filling effect, and gaps with various sizes in the epitaxial layer are fully filled.
On the other hand, the solid passivation layer 32 is deposited on the upper part of the liquid micro-gap permeation layer 31 and then annealed, so that the liquid raw material of the micro-gap permeation layer 31 is effectively prevented from completely volatilizing in the annealing process, and the micro-gap permeation layer 31 and the passivation layer 32 are fully permeated and stacked.
S7: cleaning by adopting a cleaning agent; removing the leakage barrier layer on the surface of the second semiconductor layer;
specifically, S7 includes:
s71: soaking the annealed LED chips in a cleaning agent for 5-10 minutes;
s72: washing with pure water and drying.
The cleaning is performed to remove the leakage barrier layer 3 on the surface of the second semiconductor layer 23, and only the leakage barrier layer 3 remains in the second semiconductor layer defect gap.
To ensure that only the leakage barrier layer 3 on the surface of the second semiconductor layer 23 is removed; the nature of the cleaning agent needs to be limited. In the invention, the cleaning agent with higher viscosity is adopted for cleaning, and the cleaning agent cannot permeate into the second semiconductor layer defect gap; the active ingredient of the cleaning agent is F or P, so that the solid raw material of the passivation layer can be effectively removed.
Preferably, the cleaning agent is a mixture of hydrofluoric acid, phosphoric acid and nonionic polyacrylamide. Nonionic polyacrylamides are effective in thickening such cleaner solutions.
Preferably, step S7 further includes:
forming a transparent conductive layer 6 (ITO layer) on the epitaxial layer 2; specifically, a transparent conductive layer can be formed by adopting an evaporation or magnetron sputtering mode;
etching the ITO layer to form a second exposed area; exposing the first exposed area; specifically, the transparent conductive layer is etched by using an ICP or RIE etching apparatus.
S8: forming a first electrode on the first semiconductor layer; forming a second electrode on the second semiconductor layer; and obtaining a low-leakage-rate LED chip finished product.
Specifically, a first electrode 4 is deposited on the first bare area, and a second electrode 5 is deposited on the second bare area.
Wherein the first electrode 4 and the second electrode 5 are made of one or more of Cr, al, ti, pt, ni, au, cu, ag. Preferably, the first electrode 4 and the second electrode 5 are made of Cr, al, ti, pt and Au, and have a Cr layer, an Al layer, a Ti layer, a Pt layer, and an Au layer sequentially provided on the Cr layer. The Cr layer has good cohesive force, prevents the alloy layer from falling off, and can form good ohmic contact with the semiconductor layer; the Al layer has good reflection performance, so that the overall performance of the LED chip is improved; meanwhile, in order to prevent migration of Al in the Al layer, a Ti layer is arranged on the upper part of the Al layer; pt and Au have the advantages of good conductivity, stability, good ductility and the like.
Preferably, the preparation method of the LED chip in the present invention further includes:
s9: forming an insulating protection layer on the first semiconductor layer, the first electrode, the transparent conductive layer and the second electrode;
specifically, the insulating protective layer 7 is formed by a vapor deposition (MOCVD) method; the insulating protective layer is made of SiO 2 、SiN x 、Al 2 O 3 、TiO 2 、Ti 2 O 5 One or more of the above materials.
S10: etching an opening on the insulating protective layer to expose the first electrode and the second electrode;
s11: grinding and thinning the thickness of the substrate;
s12: and (3) scribing the substrate by using laser and splitting by using a steel chopper to form crystal grains, thereby obtaining the LED chip finished product.
Correspondingly, the invention also discloses a low leakage rate LED chip, referring to FIG. 2, which comprises a substrate 1; an epitaxial layer 2 provided on the substrate 1, the epitaxial layer 2 including a first semiconductor layer 21, an active layer, and a second semiconductor layer 22 in this order; a leakage blocking layer 3 provided in the second semiconductor layer 22; a first electrode 4 provided on the first semiconductor layer 21 and a second electrode 5 provided on the second semiconductor layer; wherein the leakage barrier layer 3 comprises a micro-gap permeation layer 31 and a passivation layer 2; the micro gap permeation layer 31 and the passivation layer overlap each other after an annealing process to form the leakage barrier layer 3.
According to the invention, the electric leakage blocking layer is arranged on the epitaxial layer, so that the problem of electric leakage on the surface of the LED chip caused by that ITO and electrode metal enter the epitaxial layer through epitaxial defects in the process of forming the transparent conductive layer and the electrode is effectively prevented. Meanwhile, the leakage barrier layer is divided into a micro-gap permeation layer and a passivation layer, and the micro-gap permeation layer can fully permeate; the passivation layer can reduce interface states; the two are tightly overlapped through an annealing process, so that gaps with various sizes in the epitaxial layer are fully filled, and surface leakage current is restrained.
Specifically, referring to fig. 3, the leakage blocking layer 3 includes a micro gap permeation layer 31 and a passivation layer 32; wherein the micro gap permeation layer 31 is made of one or more of methanol, ethanol, isopropanol and acetone; the micro gap permeation layer 31 is made of small molecular carbon-containing organic matters, has small molecular weight and low boiling point, and can rapidly diffuse into the defects of the epitaxial layer at normal temperature to fill the defects. Preferably, the micro gap permeation layer 31 is made of isopropanol and/or acetone; the viscosity of the two substances is higher than that of ethanol and methanol, so that the two substances are easy to be uniformly dispersed in the LED chip; and the volatilization speed is slower than that of methanol and ethanol, and the volatilization speed is easy to control in the subsequent annealing process.
Passivation layer 32 is made of SiO 2 、SiN x 、Al 2 O 3 、TiO 2 、Ti 2 O 5 One or more of them; preferably, the passivation layer is made of SiO 2 Or SiN x Is prepared.
In order to further improve the leakage yield of the LED chip, two passivation layers are arranged on the micro-gap permeation layer 31; a first passivation layer 33 and a second passivation layer 34, respectively, the second passivation layer 34 being located on top of the first passivation layer 33; the first passivation layer 33 is made of HfO 2 、Al 2 O 3 One of them; the second passivation layer 34 is made of SiO 2 、TiO 2 One of them is made into. Preferably, the first passivation layer 33 is made of HfO 2 Made of SiO, the second passivation layer 34 2 Is prepared. Wherein, the dielectric constant of the first passivation layer 33 is higher, and the insulating property is stronger; leakage current can be effectively reduced. Meanwhile, the polarity of the raw material of the first passivation layer is strong, so that the raw material of the micro gap permeation layer 31 can be better combined with the raw material of the micro gap permeation layer.
In order to further play a role in reducing leakage current, the thickness ratio of the first passivation layer 33 to the second passivation layer 34 is 1: (2-100); preferably, the thickness ratio of the first passivation layer to the second passivation layer is 1:50 to 100, and more preferably 1:80 to 100. When the first passivation layer is too thin, the insulation function cannot be sufficiently exerted. When the first passivation layer is too thick, the insulation performance is better, but the cost is higher; meanwhile, more importantly, the liquid raw material of the micro-gap permeation layer is easy to volatilize in a large amount through the first passivation layer, and the micro-gap filling effect is poor.
Specifically, in order to enhance the efficiency of the low leakage rate LED chip of the present invention, a transparent conductive layer 6 (ITO layer) is further disposed on the second semiconductor layer 23; an insulating protective layer 7 is further arranged on the first semiconductor layer 21, the transparent conductive layer 6, the first electrode 4 and the second electrode 5; the insulating protective layer 7 is provided with openings at the electrodes to expose the first electrode 4 and the second electrode 5.
While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles of the invention, such changes and modifications are also intended to be within the scope of the invention.
Claims (10)
1. The method for improving the leakage yield of the LED chip is characterized by comprising the following steps of:
(1) Providing a substrate;
(2) Forming an epitaxial layer on the substrate, the epitaxial layer including a first semiconductor layer, an active layer, and a second semiconductor layer;
(3) Performing MESA etching on the epitaxial layer to expose the first semiconductor layer;
(4) Coating a micro-gap permeation layer on the second semiconductor layer; the micro-gap permeable layer is made of one or more of methanol, ethanol, isopropanol and acetone;
(5) Depositing a passivation layer on the micro-gap permeation layer;
(6) Annealing is carried out after the deposition is finished, so that the micro-gap permeation layer permeates the passivation layer to form a leakage barrier layer;
(7) Cleaning by adopting a cleaning agent; removing the leakage barrier layer on the surface of the second semiconductor layer, and reserving the leakage barrier layer in the defect gap of the second semiconductor layer;
(8) Forming a first electrode on the first semiconductor layer; forming a second electrode on the second semiconductor layer; and obtaining a low-leakage-rate LED chip finished product.
2. The method of improving leakage yield of an LED chip according to claim 1, wherein in step (4), a spin coater is used to coat a micro gap permeation layer on the surface of the second semiconductor layer.
3. The method for improving the leakage yield of the LED chip as claimed in claim 2, wherein the passivation layer is made of SiO 2 、SiN x 、Al 2 O 3 、TiO 2 、Ti 2 O 5 One or more of them;
in the step (5), the passivation layer is deposited by adopting a plasma chemical vapor deposition method, wherein the deposition temperature is 80-150 ℃.
4. The method of improving leakage yield of LED chips as defined in claim 3, wherein in the step (6), the annealing temperature is 100-550 ℃ and the annealing time is 0.3-1h.
5. The method of improving leakage yield of an LED chip as set forth in claim 4, wherein the step (7) includes:
(7.1) placing the annealed LED chips into a cleaning agent to be soaked for 5-10 minutes;
(7.2) rinsing with pure water and drying.
6. The method of claim 5, wherein the cleaning agent is a mixture of hydrofluoric acid, phosphoric acid and nonionic polyacrylamide.
7. The method of claim 1, wherein the passivation layer comprises a first passivation layer and a second passivation layer;
the first passivation layer is made of HfO 2 、Al 2 O 3 One of them;
the second passivation layer is made of SiO 2 、TiO 2 Is made of one of the materials.
8. The method for improving leakage yield of an LED chip of claim 7, wherein a thickness ratio of said first passivation layer to said second passivation layer is 1: (2-100).
9. A low leakage rate LED chip, comprising:
the substrate is provided with a plurality of holes,
the epitaxial layer is arranged on the substrate and comprises a first semiconductor layer, an active layer and a second semiconductor layer;
a leakage blocking layer disposed in the defect gap of the second semiconductor layer;
a first electrode disposed on the first semiconductor layer; and
a second electrode disposed on the second semiconductor layer;
the leakage blocking layer comprises a micro-gap permeation layer and a passivation layer; the micro-gap permeation layer permeates the passivation layer after an annealing process to form the leakage blocking layer; the micro-gap permeable layer is made of one or more of methanol, ethanol, isopropanol and acetone;
the first and second electrodes are made of one or more of Cr, al, ti, pt, ni, au, cu, ag.
10. The low leakage rate LED chip of claim 9, wherein said passivation layer is comprised of SiO 2 、SiN x 、Al 2 O 3 、TiO 2 、Ti 2 O 5 One or more of the above materials.
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