LED chip for preventing aluminum electrode migration

Abstract

The present invention discloses an LED chip for preventing aluminum electrode migration, comprising a light-emitting structure, an electrode structure arranged on the light-emitting structure, and an anti-migration structure, wherein the electrode structure comprises a first electrode and a second electrode, the first electrode comprises a Cr layer and an Al layer, the Cr layer is arranged on the light-emitting structure, the Al layer is arranged on the Cr layer, and the anti-migration structure is a single-layer structure or a single-layer stacked structure of at least three layers. The present invention arranges the anti-migration structure between the Cr layer and the Al layer of the first electrode, effectively preventing the metal in the Al layer from migrating to the light-emitting structure.

Description

Technical Field

[0001] The invention relates to the technical field of light emitting diodes, and in particular to an LED chip capable of preventing aluminum electrodes from migrating. Background Art

[0002] Aluminum electrode is a common electrode structure in LED chips. After aluminum is oxidized, an aluminum oxide layer is formed on the surface. Its stability is worse than that of gold, but better than other highly conductive metals, such as copper oxidation and silver sulfide. Because aluminum is cheap, it is often used as an electrode for LED chips.

[0003] However, aluminum itself has a high migration ability, and it often migrates to other metals or diffuses to the light-emitting area of ​​the chip due to temperature, humidity, pressure, and electricity, which can easily cause leakage of the LED chip.

[0004] Electromigration usually refers to the phenomenon that the movement of conductive ions under the action of an electric field causes the failure of components or circuits. There are two types of electromigration, such as the common silver ion migration that occurs on the surface of adjacent conductors and the metallized electron migration that occurs inside metal conductors. Electromigration of aluminum wires is metallized electron migration. Metals are crystals, and metal ions are arranged in order inside the crystals. When there is no external electric field, metal ions can change positions through vacancies in the lattice. This kind of metal ion movement is called self-diffusion. Because any ion close to the adjacent vacancy has the same probability of exchanging positions with the vacancy, the result of self-diffusion does not produce mass transport. When a direct current passes through a metal conductor, the electric field causes the metal ions to produce a directional movement, that is, the migration of metal ions. Electromigration is accompanied by mass transport. The so-called metal electromigration failure usually refers to the degradation or failure of device or interconnection performance caused by the mass accumulation (Pileup) of metal ions in the local area of ​​the metal layer due to the migration of metal ions, or the appearance of voids (Voids) due to mass loss. It is usually caused under high temperature and strong electric field. Different metals have different conditions for metallization electromigration. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an LED chip which can prevent the migration of aluminum electrodes, thereby preventing the migration of aluminum electrodes and improving the reliability of the chip.

[0006] In order to solve the above technical problems, the present invention provides an LED chip for preventing aluminum electrode migration, comprising a light-emitting structure, an electrode structure arranged on the light-emitting structure, and an anti-migration structure, wherein the electrode structure comprises a first electrode and a second electrode, the first electrode comprises a Cr layer and an Al layer, the Cr layer is arranged on the light-emitting structure, the Al layer is arranged on the Cr layer, and the anti-migration structure is a single-layer structure or a single-layer stacked structure of at least three layers;

[0007] When the anti-migration structure is a single-layer structure, the anti-migration structure is made of a first metal;

[0008] When the anti-migration structure is a laminated structure, the anti-migration structure includes 2n+1 layers, n is an integer, the odd-numbered layers are made of the first metal, and the even-numbered layers are made of the second metal;

[0009] The first metal is a metal whose atomic arrangement is hexagonal closest packing, and the second metal is a metal whose atomic arrangement is face-centered cubic closest packing.

[0010] As an improvement of the above solution, the metal activity of the second metal is less than the metal activity of Al.

[0011] As an improvement of the above solution, the first metal is titanium Ti, cobalt Co, zirconium Zr, beryllium Be or hafnium Hf;

[0012] The second metal is platinum Pt, rhodium Rh, palladium Pd, iridium Ir or nickel Ni.

[0013] As an improvement of the above solution, the first metal is titanium Ti, and the second metal is platinum Pt.

[0014] As an improvement of the above solution, when the anti-migration structure is a single-layer structure, its thickness is 30 to 300 nm.

[0015] As an improvement of the above solution, when the anti-migration structure is a stacked structure, the thickness of each odd-numbered layer is 30 to 150 nm, and the thickness of each even-numbered layer is 60 to 200 nm.

[0016] As an improvement of the above solution, the thickness of the Cr layer is 2-50 nm, and the thickness of the Al layer is greater than 1.5 μm.

[0017] As an improvement of the above-mentioned scheme, the light-emitting structure includes a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer on the multi-quantum well layer arranged on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer.

[0018] As an improvement of the above solution, the second electrode includes a first Au layer, a GeAu layer and a second Au layer, the first Au layer is arranged on the light-emitting structure, the GeAu layer is arranged on the first Au layer, and the second Au layer is arranged on the GeAu layer.

[0019] As an improvement of the above solution, the thickness of the first Au layer is 100-200 nm, the thickness of the GeAu layer is 50-100 nm, and the thickness of the second Au layer is 800-3000 nm.

[0020] The implementation of the present invention has the following beneficial effects:

[0021] The present invention sets an anti-migration structure between the Cr layer and the Al layer of the first electrode to effectively prevent the metal in the Al layer from migrating to the light-emitting structure. The anti-migration structure of the present invention is a single-layer structure or an odd-number stacked structure of at least three layers.

[0022] When the anti-migration structure is a single-layer structure, the anti-migration structure is made of a first metal, and the first metal is a metal with a hexagonal closest packing atomic arrangement. The present invention uses a hexagonal closest packing metal, a metal with the same coordination number as Al and a different atomic arrangement from Al, to prevent the migration of Al.

[0023] When the anti-migration structure is a stacked structure, the anti-migration structure includes 2n+1 layers, where n is an integer; wherein the odd-numbered layers are made of the first metal, and the even-numbered layers are made of the second metal, and the second metal is a metal whose atomic arrangement is face-centered cubic closest packing. The second metal is always sandwiched between two layers of the first metal. Since the coordination number of the second metal is the same as that of the first metal, but the atomic arrangement of the two is different, a dislocation stacking is formed, which more effectively prevents the migration of Al. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of an LED chip for preventing aluminum electrode migration according to the present invention. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0026] The present invention provides an LED chip for preventing aluminum electrode migration, comprising a light emitting structure 10, an electrode structure disposed on the light emitting structure 10, and an anti-migration structure 20. The LED chip of the present invention is a face-up structure, a flip-down structure, or a vertical structure.

[0027] The light emitting structure 10 of the present invention includes a GaAs substrate 11, an N-GaAs layer 12 disposed on the GaAs substrate 11, a multi-quantum well layer 13 disposed on the N-GaAs layer 12, a P-GaP layer 14 disposed on the multi-quantum well layer 13, and a transparent conductive layer 15 disposed on the P-GaP layer 14.

[0028] The electrode structure includes a first electrode 30 and a second electrode 40 . The first electrode 30 includes a Cr layer 31 and an Al layer 32 . The Cr layer 31 is disposed on the transparent conductive layer 15 , and the Al layer 32 is disposed on the Cr layer 31 .

[0029] The Cr layer 31 in the first electrode 30 is used as a bottom structure to increase the adhesion between the first electrode 30 and the light emitting structure 10 to prevent the first electrode 30 from falling off. The Al layer 32 in the first electrode 30 is used as a top structure to perform good conductivity and protection.

[0030] Specifically, the thickness of the Cr layer 31 is 2 to 50 nm. If the thickness of the Cr layer 31 is less than 2 nm, it is too thin to achieve adhesion, the electrode is easy to fall off, and the voltage is easy to fluctuate. If the thickness of the Cr layer 31 is greater than 50 nm, the Cr metal layer is easy to break. In order to ensure stable packaging wire bonding, the thickness of the Al layer 32 is greater than 1.5 μm.

[0031] The anti-migration structure 20 of the present invention is disposed between the Cr layer 31 and the Al layer 32 to prevent the metal in the Al layer 32 from migrating to the light emitting structure.

[0032] The anti-migration structure 20 is a single-layer structure or a single-layer stacked structure of at least three layers.

[0033] When the anti-migration structure 20 is a single-layer structure, the anti-migration structure 20 is made of a first metal, and the first metal is a metal whose atomic arrangement is hexagonal closest packing.

[0034] When the anti-migration structure 20 is a single-layer structure, its thickness is 30 to 300 nm. If the thickness of the anti-migration structure 20 is less than 30 nm, it is too thin and cannot play a blocking role; if the thickness of the anti-migration structure 20 is greater than 300 nm, it will change from a thin film structure to a block structure, so that stress will be generated between the anti-migration structure 20 and the Al layer 32 and the Cr layer 31, and it is easy to break.

[0035] When the anti-migration structure 20 is a stacked structure, the anti-migration structure 20 includes 2n+1 layers, where n is an integer; wherein the odd-numbered layers are made of a first metal, and the even-numbered layers are made of a second metal, and the second metal is a metal whose atomic arrangement is face-centered cubic closest packing.

[0036] Since the atomic arrangement of Al is face-centered cubic closest packing, the coordination number is 12, and the metal activity of Al is -1.662A / V, the present invention adopts a hexagonal closest packed metal with the same coordination number as Al, which can block the migration of Al. If a metal with a lower coordination number than Al is used as an anti-migration structure, pores will be generated between the two, and Al can penetrate into the metal through the pores to migrate. If a face-centered cubic closest packed metal with the same coordination number is used, the two will merge with each other, and Al can still migrate. Only by using a metal with the same coordination number or a higher coordination number than Al, and a different atomic arrangement from Al, can Al be prevented from migrating.

[0037] It should be noted that the metal activity of metals with a higher coordination number than Al is quite different from that of Al. Under different temperatures and currents, due to the different lattice expansions of the two, the overall structure of the first electrode will be affected, thereby affecting the conductivity and strength of the first electrode, and easily causing problems such as leakage, high voltage, and electrode drop.

[0038] Therefore, the first metal selected in the present invention has the same coordination number as Al and a metal activity similar to Al.

[0039] Preferably, the first metal is titanium Ti, cobalt Co, zirconium Zr, beryllium Be or hafnium Hf, but is not limited thereto.

[0040] When the anti-migration structure 20 is a stacked structure, the second metal is always sandwiched between two layers of the first metal. Since the coordination number of the second metal is the same as that of the first metal, but the atomic arrangements of the two are different, a dislocation stacking is formed, which more effectively prevents the migration of Al.

[0041] Preferably, the metal activity of the second metal is less than that of Al.

[0042] Preferably, the second metal is platinum Pt, rhodium Rh, palladium Pd, iridium Ir or nickel Ni, but is not limited thereto.

[0043] When the anti-migration structure 20 is a laminated structure, the thickness of each odd layer is 30 to 150 nm, and the thickness of each even layer is 60 to 200 nm. If the thickness of the odd layer is less than 30 nm, it is too thin to play a blocking role; if the thickness of the odd layer is greater than 150 nm, the voltage of the chip will increase, because the metal activity of the odd layer is high and it is easy to oxidize into a high resistance layer. If the thickness of the even layer is less than 60 nm, it is too thin to play a blocking role; if the thickness of the even layer is greater than 200 nm, it will cause waste.

[0044] The present invention inserts an anti-migration structure 20 into the first electrode 30 to prevent aluminum migration. If the anti-migration structure 20 is too thick, the chip voltage may be too high. Therefore, the present invention designs the structure of the second electrode 40 to prevent the chip voltage from being too high.

[0045] Specifically, the second electrode 40 includes a first Au layer 41, a GeAu layer 42 and a second Au layer 43, wherein the first Au layer 41 is disposed on the GaAs substrate 11, the GeAu layer 42 is disposed on the first Au layer 41, and the second Au layer 43 is disposed on the GeAu layer 42. The first Au layer 41 is used as a contact layer, and has the conductivity and stability of the connection; the GeAu layer 42 is used as an intermediate layer, and can increase the conductivity of the metal N type and reduce the resistance; the second Au layer 43 needs to be in contact with the package body, and has good stability, and further prevents the chip voltage from being too high.

[0046] Preferably, the thickness of the first Au layer 41 is 100-200 nm, the thickness of the GeAu layer is 50-100 nm, and the thickness of the second Au layer 42 is 800-3000 nm. If the thickness of the first Au layer 41 is greater than 100 nm, the diffusion of Ge is affected.

[0047] It should be noted that the second electrode structure 40 of the present invention is suitable for the epitaxial layer of GaAs and has good conductivity and stability. If the epitaxial layer of the present invention is made of other materials, the second electrode 40 can be selected with other structures accordingly.

[0048] It should be noted that the anti-migration structure of the present invention is mainly used in chips containing aluminum electrodes. Since aluminum is cheap, aluminum is generally used as an electrode in chips. The structure of the first electrode of the present invention is just a conventional aluminum electrode structure. If other aluminum electrode structures do not contain a Cr layer or contain other metal layers, the anti-migration structure of the present invention can also be used. The anti-migration structure of the present invention can be arranged between the aluminum layer and the light-emitting structure.

[0049] If the chip does not use aluminum as an electrode, such as the second electrode of the present invention, then the anti-migration structure of the present invention may not be required.

[0050] The present invention will be further described with specific embodiments below.

[0051] Example 1

[0052] An LED chip for preventing aluminum electrode migration comprises a light-emitting structure, an electrode structure arranged on the light-emitting structure, and an anti-migration structure, wherein the light-emitting structure comprises a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer arranged on the multi-quantum well layer on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer, wherein the electrode structure comprises a first electrode and a second electrode, wherein the first electrode comprises a Cr layer and an Al layer, wherein the Cr layer is arranged on the transparent conductive layer, and the Al layer is arranged on the Cr layer, wherein the second electrode comprises a first Au layer, a Ge layer, and a second Au layer, wherein the first Au layer is arranged on the GaAs substrate, the Ge layer is arranged on the first Au layer, and the second Au layer is arranged on the Ge layer;

[0053] The anti-migration structure is a single-layer structure, arranged between the Cr layer and the Al layer, made of Ti, and has a thickness of 30 nm.

[0054] Example 2

[0055] An LED chip for preventing aluminum electrode migration comprises a light-emitting structure, an electrode structure arranged on the light-emitting structure, and an anti-migration structure, wherein the light-emitting structure comprises a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer arranged on the multi-quantum well layer on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer, wherein the electrode structure comprises a first electrode and a second electrode, wherein the first electrode comprises a Cr layer and an Al layer, wherein the Cr layer is arranged on the transparent conductive layer, and the Al layer is arranged on the Cr layer, wherein the second electrode comprises a first Au layer, a Ge layer, and a second Au layer, wherein the first Au layer is arranged on the GaAs substrate, the Ge layer is arranged on the first Au layer, and the second Au layer is arranged on the Ge layer;

[0056] The anti-migration structure is a single-layer structure, arranged between the Cr layer and the Al layer, made of Co, and has a thickness of 80 nm.

[0057] Example 3

[0058] An LED chip for preventing aluminum electrode migration comprises a light-emitting structure, an electrode structure arranged on the light-emitting structure, and an anti-migration structure, wherein the light-emitting structure comprises a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer arranged on the multi-quantum well layer on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer, wherein the electrode structure comprises a first electrode and a second electrode, wherein the first electrode comprises a Cr layer and an Al layer, wherein the Cr layer is arranged on the transparent conductive layer, and the Al layer is arranged on the Cr layer, wherein the second electrode comprises a first Au layer, a Ge layer, and a second Au layer, wherein the first Au layer is arranged on the GaAs substrate, the Ge layer is arranged on the first Au layer, and the second Au layer is arranged on the Ge layer;

[0059] The anti-migration structure is a single-layer structure, arranged between the Cr layer and the Al layer, made of Zr, and has a thickness of 150 nm.

[0060] Example 4

[0061] An LED chip for preventing aluminum electrode migration comprises a light-emitting structure, an electrode structure arranged on the light-emitting structure, and an anti-migration structure, wherein the light-emitting structure comprises a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer arranged on the multi-quantum well layer on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer, wherein the electrode structure comprises a first electrode and a second electrode, wherein the first electrode comprises a Cr layer and an Al layer, wherein the Cr layer is arranged on the transparent conductive layer, and the Al layer is arranged on the Cr layer, wherein the second electrode comprises a first Au layer, a Ge layer, and a second Au layer, wherein the first Au layer is arranged on the GaAs substrate, the Ge layer is arranged on the first Au layer, and the second Au layer is arranged on the Ge layer;

[0062] The anti-migration structure is a single-layer structure, arranged between the Cr layer and the Al layer, made of Be, and has a thickness of 200 nm.

[0063] Example 5

[0064] An LED chip for preventing aluminum electrode migration comprises a light-emitting structure, an electrode structure arranged on the light-emitting structure, and an anti-migration structure, wherein the light-emitting structure comprises a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer arranged on the multi-quantum well layer on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer, wherein the electrode structure comprises a first electrode and a second electrode, wherein the first electrode comprises a Cr layer and an Al layer, wherein the Cr layer is arranged on the transparent conductive layer, and the Al layer is arranged on the Cr layer, wherein the second electrode comprises a first Au layer, a Ge layer, and a second Au layer, wherein the first Au layer is arranged on the GaAs substrate, the Ge layer is arranged on the first Au layer, and the second Au layer is arranged on the Ge layer;

[0065] The anti-migration structure is a single-layer structure, arranged between the Cr layer and the Al layer, made of Hf, and has a thickness of 250 nm.

[0066] Example 6

[0067] An LED chip for preventing aluminum electrode migration comprises a light-emitting structure, an electrode structure arranged on the light-emitting structure, and an anti-migration structure, wherein the light-emitting structure comprises a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer arranged on the multi-quantum well layer on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer, wherein the electrode structure comprises a first electrode and a second electrode, wherein the first electrode comprises a Cr layer and an Al layer, wherein the Cr layer is arranged on the transparent conductive layer, and the Al layer is arranged on the Cr layer, wherein the second electrode comprises a first Au layer, a Ge layer, and a second Au layer, wherein the first Au layer is arranged on the GaAs substrate, the Ge layer is arranged on the first Au layer, and the second Au layer is arranged on the Ge layer;

[0068] The anti-migration structure is a single-layer structure, arranged between the Cr layer and the Al layer, made of Ti, and has a thickness of 300 nm.

[0069] Example 7

[0070] An LED chip for preventing aluminum electrode migration comprises a light-emitting structure, an electrode structure arranged on the light-emitting structure, and an anti-migration structure, wherein the light-emitting structure comprises a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer arranged on the multi-quantum well layer on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer, wherein the electrode structure comprises a first electrode and a second electrode, wherein the first electrode comprises a Cr layer and an Al layer, wherein the Cr layer is arranged on the transparent conductive layer, and the Al layer is arranged on the Cr layer, wherein the second electrode comprises a first Au layer, a Ge layer, and a second Au layer, wherein the first Au layer is arranged on the GaAs substrate, the Ge layer is arranged on the first Au layer, and the second Au layer is arranged on the Ge layer;

[0071] The anti-migration structure is a laminated structure, which is arranged between the Cr layer and the Al layer. The laminated structure is Ti / Pt / Ti, and the thickness is 85nm / 100nm / 85nm.

[0072] Example 8

[0073] An LED chip for preventing aluminum electrode migration comprises a light-emitting structure, an electrode structure arranged on the light-emitting structure, and an anti-migration structure, wherein the light-emitting structure comprises a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer arranged on the multi-quantum well layer on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer, wherein the electrode structure comprises a first electrode and a second electrode, wherein the first electrode comprises a Cr layer and an Al layer, wherein the Cr layer is arranged on the transparent conductive layer, and the Al layer is arranged on the Cr layer, wherein the second electrode comprises a first Au layer, a Ge layer, and a second Au layer, wherein the first Au layer is arranged on the GaAs substrate, the Ge layer is arranged on the first Au layer, and the second Au layer is arranged on the Ge layer;

[0074] The anti-migration structure is a laminated structure, which is arranged between the Cr layer and the Al layer. The laminated structure is Co / Rh / Ti, and the thickness is 100nm / 150nm / 120nm.

[0075] Example 9

[0076] An LED chip for preventing aluminum electrode migration comprises a light-emitting structure, an electrode structure arranged on the light-emitting structure, and an anti-migration structure, wherein the light-emitting structure comprises a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer arranged on the multi-quantum well layer on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer, wherein the electrode structure comprises a first electrode and a second electrode, wherein the first electrode comprises a Cr layer and an Al layer, wherein the Cr layer is arranged on the transparent conductive layer, and the Al layer is arranged on the Cr layer, wherein the second electrode comprises a first Au layer, a Ge layer, and a second Au layer, wherein the first Au layer is arranged on the GaAs substrate, the Ge layer is arranged on the first Au layer, and the second Au layer is arranged on the Ge layer;

[0077] The anti-migration structure is a laminated structure, which is arranged between the Cr layer and the Al layer. The laminated structure is Co / Rh / Co / Rh / Co, and the thickness is 30nm / 60nm / 40nm / 70nm / 30nm.

[0078] Example 10

[0079] An LED chip for preventing aluminum electrode migration comprises a light-emitting structure, an electrode structure arranged on the light-emitting structure, and an anti-migration structure, wherein the light-emitting structure comprises a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer arranged on the multi-quantum well layer on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer, wherein the electrode structure comprises a first electrode and a second electrode, wherein the first electrode comprises a Cr layer and an Al layer, wherein the Cr layer is arranged on the transparent conductive layer, and the Al layer is arranged on the Cr layer, wherein the second electrode comprises a first Au layer, a Ge layer, and a second Au layer, wherein the first Au layer is arranged on the GaAs substrate, the Ge layer is arranged on the first Au layer, and the second Au layer is arranged on the Ge layer;

[0080] The anti-migration structure is a laminated structure, which is arranged between the Cr layer and the Al layer. The laminated structure is Zr / Pd / Be / Ir / Ti, and the thickness is 50nm / 70nm / 70nm / 60nm / 80nm.

[0081] Embodiment 11

[0082] An LED chip for preventing aluminum electrode migration comprises a light-emitting structure, an electrode structure arranged on the light-emitting structure, and an anti-migration structure, wherein the light-emitting structure comprises a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer arranged on the multi-quantum well layer on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer, wherein the electrode structure comprises a first electrode and a second electrode, wherein the first electrode comprises a Cr layer and an Al layer, wherein the Cr layer is arranged on the transparent conductive layer, and the Al layer is arranged on the Cr layer, wherein the second electrode comprises a first Au layer, a Ge layer, and a second Au layer, wherein the first Au layer is arranged on the GaAs substrate, the Ge layer is arranged on the first Au layer, and the second Au layer is arranged on the Ge layer;

[0083] The anti-migration structure is a laminated structure, which is arranged between the Cr layer and the Al layer. The laminated structure is Ti / Ni, Zr / Pd / Be / Ir / Ti, and the thickness is 30nm / 60nm / 40nm / 60nm / 60nm / 70nm / 70nm.

[0084] Comparative Example 1

[0085] An LED chip for preventing aluminum electrode migration comprises a light-emitting structure and an electrode structure arranged on the light-emitting structure, wherein the light-emitting structure comprises a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer arranged on the multi-quantum well layer on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer, wherein the electrode structure comprises a first electrode and a second electrode, wherein the first electrode comprises a Cr layer and an Al layer, wherein the Cr layer is arranged on the transparent conductive layer, and the Al layer is arranged on the Cr layer, and wherein the second electrode comprises a first Au layer, a Ge layer, and a second Au layer, wherein the first Au layer is arranged on the GaAs substrate, the Ge layer is arranged on the first Au layer, and the second Au layer is arranged on the Ge layer.

[0086] The chips of Examples 1 to 11 and Comparative Example 1 were subjected to aging tests, and the results are as follows:

[0087]

[0088]

[0089] From the above results, it can be seen that inserting an anti-migration structure into the aluminum electrode in the present application can prevent the migration of Al, reduce the attenuation efficiency and leakage value of the chip brightness, and improve the aging level of the chip. It should be noted that the aging level of the chip is ranked as Y1>Y2>Y3.

[0090] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. An LED chip for preventing aluminum electrode migration, characterized in that: The invention comprises a light-emitting structure, an electrode structure disposed on the light-emitting structure, and an anti-migration structure, wherein the electrode structure comprises a first electrode and a second electrode, the first electrode comprises a Cr layer and an Al layer, the Cr layer is disposed on the light-emitting structure, the Al layer is disposed on the Cr layer, the anti-migration structure is disposed between the Cr layer and the Al layer, and the anti-migration structure is a single-layer structure or a single-layer stacked structure of at least three layers; When the anti-migration structure is a single-layer structure, the anti-migration structure is made of a first metal; When the anti-migration structure is a laminated structure, the anti-migration structure includes 2n+1 layers, n is an integer, the odd-numbered layers are made of the first metal, and the even-numbered layers are made of the second metal; The first metal is a metal whose atomic arrangement is hexagonal closest packing, and the second metal is a metal whose atomic arrangement is face-centered cubic closest packing; The metal activity of the second metal is less than the metal activity of Al; When the anti-migration structure is a stacked structure, the thickness of each odd-numbered layer is 30 to 150 nm, and the thickness of each even-numbered layer is 60 to 200 nm; The second electrode includes a first Au layer, a GeAu layer and a second Au layer, the first Au layer is disposed on the light emitting structure, the GeAu layer is disposed on the first Au layer, and the second Au layer is disposed on the GeAu layer.

2. The LED chip for preventing aluminum electrode migration according to claim 1, characterized in that: The first metal is titanium Ti, cobalt Co, zirconium Zr, beryllium Be or hafnium Hf; The second metal is platinum Pt, rhodium Rh, palladium Pd, iridium Ir or nickel Ni.

3. The LED chip for preventing aluminum electrode migration as claimed in claim 2, characterized in that: The first metal is titanium Ti, and the second metal is platinum Pt.

4. The LED chip for preventing aluminum electrode migration according to claim 1, characterized in that: When the anti-migration structure is a single-layer structure, its thickness is 30-300 nm.

5. The LED chip for preventing aluminum electrode migration as claimed in claim 1, characterized in that: The thickness of the Cr layer is 2-50 nm, and the thickness of the Al layer is greater than 1.5 μm.

6. The LED chip for preventing aluminum electrode migration according to claim 1, characterized in that: The light emitting structure comprises a GaAs substrate, an N-GaAs layer arranged on the GaAs substrate, a multi-quantum well layer arranged on the N-GaAs layer, a P-GaP layer arranged on the multi-quantum well layer arranged on the N-GaAs layer, and a transparent conductive layer arranged on the P-GaP layer.

7. The LED chip for preventing aluminum electrode migration according to claim 1, characterized in that: The thickness of the first Au layer is 100~200nm, the thickness of the GeAu layer is 50~100nm, and the thickness of the second Au layer is 800~3000nm.

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