Light emitting diode and light emitting device

Abstract

The invention provides a light emitting diode and a light emitting device. The light-emitting diode comprises a substrate, wherein the substrate is provided with a first surface and a second surface which are oppositely arranged; a semiconductor laminated layer, a first electrode and a second electrode are arranged above the first surface of the substrate; a third electrode is arranged below the second surface of the substrate; the polarity of the first electrode is opposite to that of the second electrode, and the polarity of the first electrode is opposite to that of the third electrode; the first electrode and the second electrode are conducted with the test circuit; the first electrode and the third electrode are conducted with the working circuit. The first electrode and the second electrode are arranged on the same surface of the light-emitting diode, so that after the light-emitting diode is cut and before the light-emitting diode is packaged, a mature and popular standard spot measurement device in the industry can be used for directly carrying out rapid and lossless electric leakage test on the light-emitting diode, defective products are effectively screened out, and the yield and the reliability of the products are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor devices, in particular to a light-emitting diode and a light-emitting device. BACKGROUND

[0002] With the wide application of ultraviolet A (UVA) light-emitting diodes (LEDs) in the fields of industrial curing, sterilization and disinfection, photocatalytic purification, etc., the market has increasingly high requirements for the brightness of UVA LED chips. Especially in the design of small-size chip particles, how to achieve higher light output in a limited unit area has become an important technical challenge.

[0003] In order to improve the brightness of the chip, the industry generally uses patterned substrates (DPSS) to replace traditional flat substrates. However, the introduction of the DPSS substrate not only improves the brightness, but also causes the quality problem of increased chip leakage rate.

[0004] Due to the electrode distribution of the upper P and lower N of the super vertical structure LED design, a single chip particle cannot be directly screened for leakage defects through conventional point measurement methods after cutting. Existing solutions such as introducing a dielectric layer probe test or using a conductive film with a chip probe station not only have complex processes, but also lead to increased material and equipment costs. SUMMARY

[0005] In view of the defects and deficiencies of the prior art light-emitting diode, the present application provides a light-emitting diode and a light-emitting device to realize leakage screening without increasing costs.

[0006] An embodiment of the present application provides a light-emitting diode, comprising a substrate having a first surface and a second surface arranged opposite to each other. A semiconductor stack, a first electrode and a second electrode are arranged above the first surface of the substrate. A third electrode is arranged below the second surface of the substrate. The polarity of the second electrode is the same as that of the third electrode, and the polarity of the first electrode is opposite to the polarity of the second electrode and the polarity of the third electrode. The first electrode and the second electrode are in conduction with a test circuit, and the first electrode and the third electrode are in conduction with a working circuit.

[0007] According to another embodiment of the present application, a light-emitting device is provided, comprising a circuit board and a plurality of light-emitting elements arranged on the circuit board, wherein the light-emitting elements comprise the light-emitting diode of the present application.

[0008] As described above, the light-emitting diode and the light-emitting device of the present application have the following beneficial effects: The light emitting diode of the present application can use the mature and popular standard point measurement equipment in the industry to directly and quickly and non-destructively test the electrical property of the light emitting diode, i.e. leakage test, after cutting and before packaging of the light emitting diode, by setting the pair of electrodes, i.e. the first electrode and the second electrode, on the same surface of the light emitting diode, so as to effectively screen out defective products and improve the yield and reliability of the products. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 A top view structural schematic diagram of a light emitting diode in the prior art is shown.

[0010] Figure 2 A top view structural schematic diagram of a light emitting diode in the prior art is shown. Figure 1 A sectional view structural schematic diagram along the direction of A-A is shown.

[0011] Figure 3 A top view structural schematic diagram of a light emitting diode provided by the embodiment one of the present application is shown.

[0012] Figure 4 A top view structural schematic diagram of a light emitting diode provided by the embodiment one of the present application is shown. Figure 3 A sectional view structural schematic diagram along the direction of B-B is shown.

[0013] Figure 5 A structural schematic diagram of a light emitting diode provided by the embodiment one of the present application in a test structure is shown.

[0014] Figure 6 A structural schematic diagram of a light emitting device provided by the embodiment two of the present application is shown.

[0015] Element number explanation 10, circuit board; 20, light emitting element; 100, substrate; 200, semiconductor stack; 201, groove; 210, first semiconductor layer; 220, active layer; 230, second semiconductor layer; 310, first electrode; 320, second electrode; 330, third electrode; 340, insulator; 410, transparent conductive layer; 420, reflective layer; 430, protective layer; 440, barrier layer; 510, first insulating layer; 520, second insulating layer; 600, electrode layer; 700, bonding layer; 800, back gold layer. DETAILED DESCRIPTION

[0016] The embodiments of the present application will be described in detail by specific, concrete examples. Those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in the present specification. The present application can also be implemented or applied by different specific embodiments, and the details in the present specification can be modified or changed based on different views and applications without departing from the spirit of the present application.

[0017] The application provides a light emitting diode, comprising a substrate having a first surface and a second surface arranged oppositely; A semiconductor stack, a first electrode and a second electrode are arranged above the first surface of the substrate; A third electrode is arranged below the second surface of the substrate; The second electrode has the same polarity as the third electrode, and the first electrode has opposite polarity to the second electrode and the third electrode; The first electrode and the second electrode are connected to a test circuit, and the first electrode and the third electrode are connected to a working circuit.

[0018] The light emitting diode provided by the embodiment can be directly tested by using a standard point testing device which is mature and popular in the industry, and the test is fast and lossless, i.e. leakage test, before the light emitting diode is cut and packaged. The problem that the existing vertical structure light emitting diode cannot be directly tested by surface point testing due to the positive and negative working electrodes (the first electrode and the third electrode in the embodiment) being arranged on the upper and lower sides is overcome. The defective products are effectively screened out, the yield and reliability of the products are improved, and no expensive special testing device needs to be invested. Meanwhile, when the light emitting diode works, the current passes through the vertical path formed by the first electrode and the third electrode, so that the light emitting efficiency and service life of the light emitting diode are ensured.

[0019] In some embodiments, when the first electrode and the second electrode are connected to the test circuit, the first electrode is electrically connected to the test circuit through a first pad, the second electrode is directly electrically connected to the test circuit, and an insulator is arranged between the substrate and the third electrode.

[0020] The light emitting diode provided by the embodiment is adapted to two scenes as a common electrode, the first pad can provide a larger contact area and a more stable connection interface for the first electrode, the second electrode is only used as a test electrode and can be directly connected to the test circuit, so that an additional switching structure is saved and signal transmission loss is reduced. The first electrode and the second electrode can be directly adapted to the existing point testing device. Meanwhile, the insulator physically isolates the substrate and the third electrode during testing, so that abnormal current path is prevented from being formed due to accidental conduction of the third electrode, and the semiconductor stack in the light emitting diode is prevented from being broken down due to overcurrent. The electrode layout is reasonable, the test function is integrated without excessively affecting the light emitting efficiency, and the compactness and performance stability of the chip are maintained.

[0021] In some embodiments, when the first electrode and the third electrode are connected to the working circuit, the first electrode is electrically connected to the working circuit through a first pad, and the third electrode is electrically connected to the working circuit through a second pad.

[0022] The first electrode of the light emitting diode of the embodiment is connected with the working circuit through the first pad, and the third electrode is connected with the working circuit through the second pad, thereby providing firm mechanical fixation and excellent electrical interconnection for the final packaging, and ensuring long-term reliability of the light emitting diode in application.

[0023] In some embodiments, the ratio of the area of the semiconductor stack to the area of the first surface and the ratio of the area of the second electrode to the area of the first surface are between (0.25-0.85):(0.005-0.04).

[0024] The light emitting diode of the embodiment can ensure that the semiconductor stack (i.e., the effective light emitting area) occupies a dominant area on the first surface by limiting the area ratio range of the semiconductor stack and the second electrode, thereby avoiding the light emitting area from being squeezed due to excessive space occupation of the second electrode, preventing significant decline in core performance such as brightness and light emitting efficiency of the light emitting diode, and reserving sufficient area for the second electrode to meet the stable electrical connection requirement during testing.

[0025] In some embodiments, the ratio of the area of the first electrode to the area of the first surface and the ratio of the area of the second electrode to the area of the first surface are between (0.02-0.16):(0.005-0.04).

[0026] The light emitting diode of the embodiment can optimize the quality of the test circuit itself by limiting the area ratio of the first electrode and the second electrode to the first surface, thereby ensuring that the two test electrodes have matching current carrying capacity and contact resistance, avoiding the current bottleneck or probe contact failure caused by the small area of one electrode, and ensuring the stability, repeatability and accuracy of the test results.

[0027] In some embodiments, the ratio of the area of the semiconductor stack, the first electrode, and the second electrode to the area of the first surface is between (0.25-0.85):(0.02-0.16):(0.005-0.04).

[0028] The light emitting diode of the embodiment can ensure that the semiconductor stack (i.e., the effective light emitting area) occupies a dominant area on the first surface by limiting the area ratio range of the three, thereby avoiding the light emitting area from shrinking due to excessive space occupation of the first electrode and the second electrode; at the same time, the light emitting diode reserves an appropriate area ratio for the first electrode and the second electrode, thereby ensuring that the two can form a stable test circuit. The light emitting diode balances the spatial requirements of light emitting performance and test function, so that the light emitting diode has high efficient leakage screening capability while the core light emitting performance is not affected.

[0029] In some embodiments, the first surface of the substrate is rectangular or square, projections of the first electrode and the second electrode on the substrate are located at different corner positions of the first surface respectively, and a center of the first electrode and a center of the second electrode are located on a same diagonal line of the first surface.

[0030] The light emitting diode of the embodiment sets the first electrode and the second electrode at different corners and centers on the same diagonal line, so that the two electrodes form a clear and fixed spacing and positional relationship, which can adapt to the probe spacing design of the existing point testing device (without adjusting the probe position), and the probe can be quickly aligned with the two electrodes during testing, avoiding the probe deviation and contact failure caused by irregular electrode position. At the same time, the diagonal distribution maximizes the spacing, which can reduce the signal interference between the two electrodes during testing, and further improve the convenience of point testing operation and the accuracy of test results.

[0031] In some embodiments, the semiconductor stack includes a first semiconductor layer, an active layer and a second semiconductor layer stacked in sequence from top to bottom, and at least one recess is arranged in the semiconductor stack, the recess penetrating through the second semiconductor layer, the active layer and at least part of the first semiconductor layer. A barrier layer is arranged between the semiconductor stack and the substrate, and the barrier layer is arranged above the first surface corresponding to the area other than the area where the recess is located. The first electrode and the second electrode are both arranged above the barrier layer and are electrically connected to the barrier layer.

[0032] In the light emitting diode of the embodiment, the barrier layer is arranged in the area other than the recess, which can provide stable support and electrical connection basis for the first electrode and the second electrode, and meet the leakage detection requirement in the testing stage. In the working stage, the barrier layer can also work with the first electrode and the third electrode to ensure the stable transmission of vertical current through precise electrical conduction.

[0033] In some embodiments, a transparent conductive layer, a reflective layer and a protective layer are sequentially arranged below the second semiconductor layer from top to bottom, and the barrier layer is located below the protective layer.

[0034] The light emitting diode of the embodiment forms a multilayer stack structure of "transparent conductive layer-reflection layer-protection layer-barrier layer" from the second semiconductor layer to the barrier layer, the transparent conductive layer protects the second semiconductor layer from current concentration damage; the reflection layer protects the light emitting structure of the active layer; the protection layer prevents the reflection layer from being scratched or oxidized in the subsequent process, ensures the long-term stability of the optical performance of the reflection layer, and maintains the persistence of the light emitting efficiency of the light emitting diode; the barrier layer further separates the protection layer and the substrate to avoid the adverse interaction between the substrate and the semiconductor stack. The multilayer protection system can effectively resist physical damage, chemical corrosion and electrical interference in the manufacturing, testing, packaging and application process of the light emitting diode, which is conducive to improving the structural reliability and service life of the light emitting diode and reducing the risk of late failure.

[0035] In some embodiments, a first insulating layer is arranged between the transparent conductive layer and the reflection layer, the first insulating layer extends from the area where the semiconductor stack is located to cover the areas where the first electrode and the second electrode are located, and the side wall of the groove is provided with the first insulating layer; At least one through hole is arranged in the first insulating layer below the transparent conductive layer, and the reflection layer is arranged in the through hole to be electrically connected with the transparent conductive layer; Corresponding to the area where the first electrode is located, the first insulating layer above the barrier layer has a first discontinuous area, the first electrode is arranged in the first discontinuous area, and the first electrode is electrically connected with the barrier layer; corresponding to the area where the second electrode is located, the first insulating layer above the barrier layer has a second discontinuous area, the second electrode is arranged in the second discontinuous area, and the second electrode is electrically connected with the barrier layer.

[0036] The light emitting diode of the embodiment realizes the selective electrical connection of the transparent conductive layer and the reflection layer at the preset position by arranging the first insulating layer between the transparent conductive layer and the reflection layer and arranging the through hole in the first insulating layer, which not only ensures the vertical conduction of the current, but also completely eliminates the short circuit or leakage risk of the transparent conductive layer and the reflection layer in other areas due to direct contact, thereby improving the yield and reliability of the light emitting diode.

[0037] In some embodiments, corresponding to the area where the semiconductor stack and the first electrode are located, the second insulating layer, the electrode layer and the bonding layer are sequentially arranged between the barrier layer and the substrate from top to bottom, the second insulating layer is also arranged below the first insulating layer in the groove, the electrode layer is also arranged below the second insulating layer in the groove and the bottom wall of the groove, and the bonding layer is also arranged below the electrode layer in the groove; The barrier layer under the second electrode is electrically insulated from the barrier layer under the semiconductor stack through the second insulating layer, the electrode layer is arranged under the barrier layer under the second electrode, the electrode layer under the second electrode has a third discontinuous region, the second insulating layer is arranged in the third discontinuous region, and the barrier layer under the second electrode is electrically connected with the electrode layer under the semiconductor stack.

[0038] The light-emitting diode of the embodiment can isolate the electrode layer and the barrier layer by arranging the second insulating layer, and prevent electric leakage therebetween. The electrode layer covers the bottom wall and the sidewall under the groove, fills the structural vacancy in the groove region, enhances the connection stability of the semiconductor stack and the underlying multilayer structure, and the electrode layer in the groove is electrically connected with the first semiconductor layer, which can guide the current of the first semiconductor layer to uniformly flow into the main channel of the electrode layer below, and reduce the hot spot effect caused by current concentration. The bonding layer can improve the interfacial bonding force between the electrode layer and the substrate, and avoid interlayer separation of the light-emitting diode during packaging, soldering or thermal cycling. The coordinated coverage of the multilayer structure in the groove region effectively solves the problem of structural weakness caused by the groove, reduces the risk of light-emitting diode failure caused by structural defects, and improves the overall mechanical reliability.

[0039] In some embodiments, a back gold layer is arranged between the substrate and the third electrode.

[0040] The back gold layer in the light-emitting diode of the embodiment is arranged on the second surface of the substrate (i.e., the side where the third electrode is located), which can directly form a stable electrical connection interface with the third electrode. The back gold layer can greatly reduce the contact resistance between the third electrode and the external circuit (such as the packaging pin), reduce the loss in the current transmission process, and at the same time, the back gold layer can increase the current conduction area, so that the vertical current is uniformly distributed under the substrate, avoiding the hot spot effect caused by the excessively high local current density, and ensuring the electrical stability and light-emitting performance consistency of the light-emitting diode during operation.

[0041] Another embodiment of the present application provides a light-emitting device, which comprises a circuit board and a plurality of light-emitting elements arranged on the circuit board, and the light-emitting elements comprise the light-emitting diode provided by the present application.

[0042] The leakage of the light-emitting diode is measured, and the defective light-emitting diode is screened out, so as to improve the reliability and yield of the final product.

[0043] Figure 1 And Figure 2A light emitting diode of a super vertical structure in the prior art is shown, which includes a first electrode 310 and a third electrode 330 with opposite polarities.0042.The light emitting device includes the light emitting diode described above, and thus can also be directly subjected to point testing using existing point testing equipment. The third electrode 330, for example, the first electrode 310 is a P electrode, and the third electrode 330 is an N electrode, and the first electrode 310 and the third electrode 330 are respectively located on the upper side and the lower side of the light emitting diode. In order to improve the brightness of the light emitting diode, a DPSS substrate is generally selected to replace a flat substrate for epitaxial growth, but the introduction of the DPSS substrate brings about a particularly prominent problem of electric leakage.

[0044] Because the first electrode 310 and the third electrode 330 are respectively located on the upper side and the lower side of the light emitting diode, this structure causes a single light emitting diode to be unable to be subjected to point testing for screening of light emitting diodes with electric leakage (in contrast to a flip design, in which the P / N poles are located on the same side, facilitating relevant detection). In the production and detection link, if a dieprober machine is used for detection, conductive film needs to be used, and the use of the conductive film not only increases the complexity of the production process, but also significantly increases the production cost.

[0045] Therefore, how to effectively solve the problem of screening of chips with electric leakage after the use of a DPSS substrate without significantly increasing the cost is a problem to be solved by the present application.

[0046] Based on the background art and the technical defects described above, the present application provides a light emitting diode and a light emitting device. The following embodiments are described in detail.

[0047] Embodiment One The present embodiment provides a light emitting diode, as shown in Figure 3 and Figure 4 The light emitting diode includes a substrate 100 having a first surface and a second surface (i.e., the upper surface and the lower surface of the substrate 100) arranged opposite to each other. A semiconductor stack 200, a first electrode 310 and a second electrode 320 are arranged above the first surface of the substrate 100. A third electrode 330 is arranged below the second surface of the substrate 100.

[0048] The substrate 100 has the function of providing mechanical support for the structure on the first surface thereof, and also has the function of heat dissipation. The substrate 100 in the present embodiment can be a conductive substrate for providing electrical connection, and the material thereof can be, for example, silicon, silicon carbide, or metal, and the metal can be, for example, Ni, Au, Cu, Mo, Pd, In, W, Ta, Nb, or an alloy of the above-mentioned metal materials.

[0049] The polarity of the first electrode 310 is opposite to that of the second electrode 320, the polarity of the first electrode 310 is opposite to that of the third electrode 330, and the polarity of the second electrode 320 is the same as that of the third electrode 330. The first electrode 310 is a P electrode, and the second electrode 320 and the third electrode 330 are N electrodes in the embodiment, and the material of the first electrode 310 can be Ti, Pt, Au, Ni, Au, Sn, etc., and the material of the second electrode 320 and the third electrode 330 can be at least one metal material in Ag, Al, Cu, Au.

[0050] The first electrode 310 and the second electrode 320 are in conduction with the test circuit. The first electrode 310 and the third electrode 330 are in conduction with the working circuit.

[0051] In the light emitting diode provided by the embodiment, the first electrode 310 is a common electrode adapted to two scenes (i.e., used for electrical connection with the test circuit or used for electrical connection with the working circuit), the second electrode 320 is arranged on the same surface as the first electrode 310, and the second electrode 320 is only used for electrical connection with the test circuit. After the light emitting diode is cut and before it is packaged, the mature and popular standard point measurement equipment in the industry is used to directly perform rapid and non-destructive electrical property test (i.e., leakage test) on the light emitting diode, which overcomes the problem that the existing vertical structure light emitting diode cannot be directly surface point measured due to the separation of the positive and negative electrodes (i.e., the first electrode 310 and the third electrode 330) on the upper and lower sides. The light emitting diode provided by the embodiment can effectively screen out defective products with leakage, improve the yield and reliability of the product, and does not need to invest in expensive special test equipment. At the same time, when the light emitting diode works, the current passes through the vertical path composed of the first electrode 310 and the third electrode 330, which ensures the light emitting efficiency and service life of the light emitting diode.

[0052] In an optional embodiment, as Figure 5As shown, the first electrode 310 is electrically connected with the first pad, when the first electrode 310 and the second electrode 320 are in conduction with the test circuit, the first electrode 310 is electrically connected with the test circuit through the first pad, and the second electrode 320 is directly electrically connected with the test circuit, the first electrode 310 and the second electrode 320 can be well adapted to the existing point test equipment to screen out defective products with leakage, and the insulator 340 is arranged between the substrate 100 and the third electrode 330, thereby, when leakage screening is performed, the substrate 100 and the third electrode 330 are electrically insulated by the insulator 340, the third electrode 330 is prevented from forming an abnormal current path due to accidental conduction, and the semiconductor stack 200 inside the light emitting diode is prevented from being broken down due to overcurrent. Since the first electrode 310 is a common electrode, the first pad can provide the first electrode 310 with a larger contact area and a more stable connection interface, the second electrode 320 only serves as a test electrode and can be directly connected with the test circuit, thereby saving an additional switching structure and reducing signal transmission loss, and the first electrode 310 and the second electrode 320 can be directly adapted to the existing point test equipment.

[0053] In an optional embodiment, the third electrode 330 is electrically connected with the second pad, when the first electrode 310 and the third electrode 330 are in conduction with the working circuit, the first electrode 310 is electrically connected with the working circuit through the first pad, and the third electrode 330 is electrically connected with the working circuit through the second pad. By arranging the first pad and the second pad, a stable mechanical fixation and excellent electrical interconnection are provided for the final package, and the long-term reliability of the light emitting diode in application is ensured.

[0054] In an optional embodiment, the ratio of the area of the semiconductor stack 200 on the first surface of the substrate 100 (i.e. the area of the first surface occupied by the orthogonal projection of the semiconductor stack 200 on the first surface) to the area of the second electrode 320 on the first surface of the substrate 100 (i.e. the area of the first surface occupied by the orthogonal projection of the second electrode 320 on the first surface) is between (0.25-0.85):(0.005-0.04). When the second electrode 320 is arranged, a small part of the light emitting area will be sacrificed, that is, the second electrode 320 will occupy part of the region where the semiconductor stack 200 should be arranged, by limiting the area ratio of the semiconductor stack 200 to the second electrode 320, it can be ensured that the semiconductor stack 200 (i.e. the effective light emitting area) occupies a dominant area on the first surface, and the light emitting area is prevented from being squeezed due to excessive occupation of space by the second electrode 320, which not only prevents the core performance of the light emitting diode such as brightness and light emitting efficiency from being significantly reduced, but also reserves sufficient area for the second electrode 320 to meet the stable electrical connection requirement during testing.

[0055] In an optional embodiment, the ratio of the area of the first electrode 310 on the first surface of the substrate 100 (i.e., the area of the orthographic projection of the first electrode 310 on the first surface) to the area of the second electrode 320 on the first surface of the substrate 100 (i.e., the area of the orthographic projection of the second electrode 320 on the first surface) is between (0.02-0.16):(0.005-0.04). When detecting the leakage current of the light-emitting diode, the first electrode 310 and the second electrode 320 are a pair of test electrodes, and by limiting the ratio of the areas of the first electrode 310 and the second electrode 320 on the first surface, the quality of the test circuit itself is optimized, and it is ensured that the two test electrodes have matched current carrying capacity and contact resistance, so as to avoid that one electrode becomes a current bottleneck or causes probe contact failure due to too small area, and to ensure the stability, repeatability and accuracy of the point measurement process.

[0056] In an optional embodiment, the ratio of the area of the semiconductor stack 200 on the first surface of the substrate 100, the area of the first electrode 310 on the first surface of the substrate 100, and the area of the second electrode 320 on the first surface of the substrate 100 is between (0.25-0.85):(0.02-0.16):(0.005-0.04). By limiting the area ratios of the semiconductor stack 200, the first electrode 310 and the second electrode 320, it is ensured that the semiconductor stack 200 (i.e., the effective light-emitting area) occupies a dominant area of the first surface, and the light-emitting area is prevented from shrinking due to excessive occupation of space by the first electrode 310 and the second electrode 320; at the same time, appropriate area ratios are reserved for the first electrode 310 and the second electrode 320, so as to ensure that the two electrodes can form a stable test circuit; the spatial requirements of the light-emitting performance and the test function can be balanced, so that the light-emitting diode has high leakage current screening capability while the core light-emitting performance is not affected.

[0057] In an optional embodiment, as shown in Figure 3 , the first surface of the substrate 100 is rectangular or square, the orthographic projections of the first electrode 310 and the second electrode 320 on the substrate 100 are located at different corner positions of the first surface (i.e., at two of the four corners of the first surface), and the center of the first electrode 310 and the center of the second electrode 320 are located on the same diagonal of the first surface. In this way, the two electrodes form a clear and fixed spacing and positional relationship, which can adapt to the probe spacing design of the existing point measurement equipment, so that the probes can quickly align the two electrodes during testing without adjusting the positions of the probes, and the probe offset and contact failure caused by irregular electrode positions are avoided; at the same time, the diagonal distribution maximizes the spacing, which can reduce the signal interference between the two electrodes during testing, and further improves the convenience of the point measurement operation and the accuracy of the detection results.

[0058] In an optional embodiment, as shown in Figure 4 andFigure 5 As shown, the semiconductor stack 200 includes a first semiconductor layer 210, an active layer 220, and a second semiconductor layer 230. The second semiconductor layer 230 is formed over the first surface of the substrate 100, the active layer 220 is then formed over the second semiconductor layer 230, and finally, the first semiconductor layer 210 is formed over the active layer 220. The first semiconductor layer 210 and the second semiconductor layer 230 have opposite polarities. In this embodiment, the first semiconductor layer 210 is an N-type semiconductor layer, and the second semiconductor layer 230 is a P-type semiconductor layer. In this case, the first semiconductor layer 210 is doped with an N-type dopant to provide electrons, and the N-type dopant can be Si, Ge, Sn, Se, Te, etc. The second semiconductor layer 230 is doped with a P-type dopant to provide holes, and the P-type dopant can be Mg, Zn, Ca, Sr, Ba, etc. A rough structure (not labeled in the figure) can be formed on the upper surface of the first semiconductor layer 210. The rough structure can improve the external quantum efficiency and is beneficial to improve the light-emitting effect of the light-emitting diode. The active layer 220 is the main area for light emission of the light-emitting diode and provides radiation for electron-hole recombination. The active layer 220 can be a single quantum well structure or a multiple quantum well (MQWs) structure. The multiple quantum well layer structure is formed by alternately stacking quantum potential well layers and quantum potential barrier layers to form a periodic multilayer structure. The quantum potential barrier layer has a larger band gap than the quantum potential well layer. The quantum potential well layer and the quantum potential barrier layer can be, for example, GaN layers, AlGaN layers, or AlGaInP layers. To improve the light-emitting efficiency of the active layer 220, the depth of the quantum well, the number of layers, the thickness, and / or other characteristics of the pairs of quantum potential well layers and quantum potential barrier layers in the active layer 220 can be changed.

[0059] The semiconductor stack 200 includes at least one recess 201. The recess 201 extends through the second semiconductor layer 230, the active layer 220, and at least part of the first semiconductor layer 210.

[0060] A barrier layer 440 is provided between the semiconductor stack 200 and the first surface of the substrate 100. Specifically, the barrier layer 440 is provided below the second semiconductor layer 230 and extends to cover the area below the first electrode 310 and the second electrode 320. The barrier layer 440 is electrically connected to the first electrode 310, and the barrier layer 440 below the second electrode 320 is electrically connected to the second electrode 320. The barrier layer 440 can provide stable support and electrical connection basis for the first electrode 310 and the second electrode 320 to meet the leakage detection requirements in the test phase. At the same time, in the working phase, the barrier layer 440 can also work with the first electrode 310 and the third electrode 330 to ensure stable transmission of vertical current through precise electrical conduction. The material of the barrier layer 440 can be, for example, Ti, Pt, Au, Ni, etc.

[0061] In an optional embodiment, the second semiconductor layer 230 is sequentially provided with a transparent conductive layer 410, a reflective layer 420, a protective layer 430 and a barrier layer 440 from top to bottom.

[0062] The transparent conductive layer 410 is formed on a part of the lower surface of the second semiconductor layer 230, and the transparent conductive layer 410 is in ohmic contact with the second semiconductor layer 230. The material of the transparent conductive layer 410 is selected from transparent conductive materials, for example, at least one of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrO x , RuO x , RuO x / TO, Ni / IrO x / Au, Ni / IrO x / Au / ITO.

[0063] The reflective layer 420 is arranged below the lower surface of the transparent conductive layer 410, and has the function of reflecting the light radiated from the side of the semiconductor stack 200 towards the substrate 100, so that the light is returned to the semiconductor stack 200 and radiated from the light-emitting side, thereby improving the light-emitting effect of the light-emitting diode. The reflective layer 420 can be in direct contact with the transparent conductive layer 410, or a first insulating layer 510 can be formed on the lower surface of the transparent conductive layer 410, and a plurality of through holes can be formed on the first insulating layer 510 in the corresponding region, the through holes penetrating the first insulating layer 510, and then the reflective layer 420 is formed on the lower surface of the first insulating layer 510 in the corresponding region, and the reflective layer 420 is also filled in the through holes, forming a CBL structure to improve the distribution of current and improve the light-emitting efficiency, and also improve the heat dissipation performance. The material of the reflective layer 420 is formed of at least one metal selected from Ag, Al, Ni, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au and Hf.

[0064] The protective layer 430 is arranged on the lower surface of the reflective layer 420 and wraps the sidewall of the reflective layer 420. The protective layer 430 has the function of preventing the metal of the reflective layer 420 from diffusing to the other film layers away from the reflective layer 420 on the side of the protective layer 430, thereby affecting the reflection effect. The material of the protective layer 430 can be, for example, Pt, Au, TiW, Cr, etc.

[0065] In an optional embodiment, a first insulating layer 510 is disposed between the transparent conductive layer 410 and the reflective layer 420. The first insulating layer 510 further extends to cover the area below the first electrode 310 and the second electrode 320, and extends to cover the sidewall of the groove 201. The first insulating layer 510 is made of an insulating material to separate the P / N current. The insulating material can be, for example, SiO2, SiN, or SiO2. x N y At least one of TiO2, Si3N4, Al2O3, TiN, AlN, ZrO2, TiAlN, TiSiN, HfO2, TaO2, or MgF2.

[0066] At least one through-hole is provided in the first insulating layer 510 located below the transparent conductive layer 410. The through-hole penetrates the first insulating layer 510, and the reflective layer 420 fills the through-hole to be electrically connected to the transparent conductive layer 410. In order to improve the adhesion between the transparent conductive layer 410 and the first insulating layer 510 or between the reflective layer 420, an adhesive layer can be provided between the transparent conductive layer 410 and the first insulating layer 510, and between the transparent conductive layer 410 and the reflective layer 420. The material of the adhesive layer can be selected from aluminum oxide (Al2O3), magnesium oxide (MgO), tantalum oxide (Ta2O5), silicon nitride (SiNx), transparent conductive oxide, aluminum (Al), aluminum-silver alloy (AlAg), titanium (Ti), titanium-tungsten alloy (TiW), chromium (Cr), or nickel (Ni), etc., wherein the transparent conductive oxide can be indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), zinc oxide (ZnO), indium zinc oxide (IZO), etc.

[0067] Below the first electrode 310, the first insulating layer 510 has a first discontinuity region, which exposes the upper surface of the barrier layer 440. The first electrode 310 is disposed in the first discontinuity region to be electrically connected to the barrier layer 440.

[0068] Below the second electrode 320, the first insulating layer 510 has a second discontinuity region, which exposes the upper surface of the barrier layer 440. The second electrode 320 is disposed in the second discontinuity region to be electrically connected to the barrier layer 440.

[0069] In an optional embodiment, in the region where the semiconductor stack 200 and the first electrode 310 are located, a second insulating layer 520, an electrode layer 600 and a bonding layer 700 are sequentially disposed between the barrier layer 440 and the substrate 100 from top to bottom.

[0070] The second insulating layer 520 is also disposed below the first insulating layer 510 within the groove 201. Corresponding to the region where the second electrode 320 is located, there is a gap between the barrier layer 440 below the second electrode 320 and the barrier layer 440 below the semiconductor stack 200. The second insulating layer 520 is disposed within this gap to provide electrical insulation between the second electrode 320 and the second semiconductor layer 230. The material of the second insulating layer 520 is an insulating material, such as SiO2, SiN, or SiO2. x N y At least one of TiO2, Si3N4, Al2O3, TiN, AlN, ZrO2, TiAlN, TiSiN, HfO2, TaO2, or MgF2.

[0071] The electrode layer 600 is also disposed below the second insulating layer 520 within the groove 201 and on the bottom wall of the groove 201. Corresponding to the region where the second electrode 320 is located, the electrode layer 600 extends to cover the lower surface of the barrier layer 440 below the second electrode 320. The electrode layer 600 below the second electrode 320 has a third discontinuous region, within which the second insulating layer 520 is disposed. The length of the third discontinuous region is less than the length of the interval region; that is, the outer edge of the barrier layer 440 below the second electrode 320 is greater than the outer edge of the second insulating layer 520 below the barrier layer 440, thus providing an electrical connection between the barrier layer 440 below the second electrode 320 and the electrode layer 600 below the second electrode 320. The polarity of the electrode layer 600 is opposite to that of the first electrode 310. When the first electrode 310 is a P electrode, the electrode layer 600 uses an N electrode material. In this case, the material of the electrode layer 600 can be, for example, Al, Cr, Ti, Pt, Ni, Au, Sn, etc.

[0072] A bonding layer 700 is also disposed below the electrode layer 600 within the groove 201. The bonding layer 700 is used to bond the semiconductor stack 200 of the light-emitting diode to the substrate 100. The material of the bonding layer 700 is a metallic material, such as at least one of Ti, Ni, Sn, Au, Pt, and their alloys.

[0073] In optional embodiments, such as Figure 4 As shown, a back gold layer 800 is disposed between the substrate 100 and the third electrode 330. The back gold layer 800 is disposed below the second surface of the substrate 100 and has functions such as providing mechanical support, enhancing heat dissipation performance, shielding electromagnetic interference, and providing a ground plane. The material of the back gold layer 800 can be, for example, at least one of Ti, Ni, Pt, and Au.

[0074] Example 2 This embodiment provides a light-emitting device, such as... Figure 6As shown, the light emitting device includes a circuit board 10 and a plurality of light emitting elements 20 disposed on the circuit board 10, the light emitting elements 20 including the light emitting diode provided in Embodiment One. The light emitting diode of Embodiment One is provided with the second electrode 320, such that the second electrode 320 is located on the same surface as the first electrode 310, and the second electrode 320 is only used for electrical connection with the test circuit, and the first electrode 310 is used for electrical connection with both the test circuit and the working circuit, such that the first electrode 310 and the second electrode 320 can be directly tested by using the existing standard point test equipment, which can effectively screen out defective products with leakage, improve the yield and reliability of the product, and there is no need to invest in expensive special test equipment. The light emitting element 20 of the present embodiment uses the light emitting diode provided in Embodiment One, which can effectively screen out defective products with leakage and improve the yield and reliability of the light emitting device without significantly increasing the cost.

[0075] The above embodiments are only illustrative of the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought of the present application should be covered by the claims of the present application.

Claims

1. A light emitting diode, characterized by, The substrate has a first surface and a second surface arranged oppositely; A semiconductor stack, a first electrode and a second electrode are arranged above the first surface of the substrate; A third electrode is arranged below the second surface of the substrate; The second electrode has the same polarity as the third electrode, and the first electrode has opposite polarity to both the second electrode and the third electrode; The first electrode and the second electrode are electrically connected to a test circuit, and the first electrode and the third electrode are electrically connected to a working circuit.

2. The light emitting diode of claim 1, wherein, When the first electrode and the second electrode are electrically connected to the test circuit, the first electrode is electrically connected to the test circuit through a first pad, and the second electrode is directly electrically connected to the test circuit, and an insulator is arranged between the substrate and the third electrode.

3. The light emitting diode of claim 1, wherein, When the first electrode and the third electrode are electrically connected to the working circuit, the first electrode is electrically connected to the working circuit through a first pad, and the third electrode is electrically connected to the working circuit through a second pad.

4. The light emitting diode of claim 1, wherein, The ratio of the area of the semiconductor stack to the area of the second electrode on the first surface is between (0.25-0.85):(0.005-0.04).

5. The light emitting diode of claim 1, wherein, The ratio of the area of the first electrode to the area of the second electrode on the first surface is between (0.02-0.16):(0.005-0.04).

6. The light emitting diode of claim 1, wherein, The ratio of the area of the semiconductor stack, the first electrode and the second electrode on the first surface is between (0.25-0.85):(0.02-0.16):(0.005-0.04).

7. The light emitting diode of claim 1, wherein, The first surface of the substrate is rectangular or square, the projections of the first electrode and the second electrode on the substrate are located at different corner positions of the first surface, and the centers of the first electrode and the second electrode are located on the same diagonal of the first surface.

8. The light emitting diode of claim 1, wherein, The semiconductor stack includes a first semiconductor layer, an active layer and a second semiconductor layer stacked in order from top to bottom, and at least one recess is arranged in the semiconductor stack, which penetrates the second semiconductor layer, the active layer and at least part of the first semiconductor layer. A barrier layer is arranged between the semiconductor stack and the substrate, and the barrier layer is arranged above the first surface corresponding to the area except the area where the recess is located, and the first electrode and the second electrode are both arranged above the barrier layer and electrically connected to the barrier layer.

9. The light emitting diode of claim 8, wherein, A transparent conductive layer, a reflective layer and a protective layer are arranged in order from top to bottom below the second semiconductor layer, and the barrier layer is located below the protective layer.

10. The light emitting diode of claim 9, wherein, A first insulating layer is arranged between the transparent conductive layer and the reflective layer, the first insulating layer extends and covers the areas where the first electrode and the second electrode are located from the area where the semiconductor stack is located, and the sidewall of the recess is provided with the first insulating layer; At least one through hole is arranged in the first insulating layer below the transparent conductive layer, and the reflective layer is arranged in the through hole to be electrically connected to the transparent conductive layer; Corresponding to the region where the first electrode is located, the first insulating layer above the barrier layer has a first discontinuous region, the first electrode is arranged in the first discontinuous region, and the first electrode is electrically connected to the barrier layer.

11. The light emitting diode of claim 10, wherein, Corresponding to the region where the semiconductor stack and the first electrode are located, a second insulating layer, an electrode layer and a bonding layer are sequentially arranged from top to bottom between the barrier layer and the substrate, the second insulating layer is further arranged below the first insulating layer in the groove, the electrode layer is further arranged below the second insulating layer in the groove and on the bottom wall of the groove, and the bonding layer is further arranged below the electrode layer in the groove. The barrier layer below the second electrode is electrically insulated from the barrier layer below the semiconductor stack through the second insulating layer, the electrode layer is arranged below the barrier layer below the second electrode, the electrode layer below the second electrode has a third discontinuous region, the second insulating layer is arranged in the third discontinuous region, and the barrier layer below the second electrode is electrically connected to the electrode layer below the semiconductor stack.

12. The light emitting diode of claim 1, wherein, A back gold layer is arranged between the substrate and the third electrode.

13. A light-emitting device, characterized in that, The light emitting element includes a circuit board and a plurality of light emitting elements arranged on the circuit board, and the light emitting element includes the light emitting diode of any one of claims 1-12.

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