Light emitting diode and light emitting device

Abstract

The application provides a light emitting diode and a light emitting device. The light emitting diode is provided with a first insulating layer. A first part of the first insulating layer is arranged around a first electrode, and a second part of the first insulating layer is arranged around a sidewall between a second mesa and the first mesa and a surface of a part of the second mesa. The first insulating layer is arranged to form a duck mouth clamp structure around the first electrode and the second electrode. The structure can effectively prevent the diffusion of metal elements in the electrode into the semiconductor epitaxial stack or at the sidewall of the semiconductor epitaxial stack. The first insulating layer can also avoid the direct contact between the edge of the metal electrode and the semiconductor epitaxial stack, avoid the metal-epitaxial interface problem, effectively inhibit the migration and failure of the metal elements. The forming position of the first insulating layer can be adjusted to passivate the metal electrode or ITO contact material boundary to improve the yield.

Description

Technical Field

[0001] This invention relates to the field of semiconductor devices and apparatus, and particularly to a light-emitting diode and a light-emitting device. Background Technology

[0002] Light-emitting diodes (LEDs) have advantages such as high luminous intensity, high efficiency, small size, and long lifespan, and are considered one of the most promising light sources today. In recent years, LEDs have been widely used in daily life, such as lighting, signal display, backlighting, automotive lights, and large-screen displays. At the same time, these applications have also placed higher demands on the brightness and luminous efficiency of LEDs.

[0003] For ultraviolet LEDs, the epitaxial structure is typically made of AlGaN, a ternary crystal material. During the epitaxial growth process, inconsistent crystal orientations and difficulties in controlling defects and impurities at grain boundaries are common. When designing and fabricating the chip, the P / N electrodes are directly deposited on the surface of the epitaxial structure. The electrode sidewall material is relatively thin, significantly increasing the probability of migration failure at the AlGaN interface. This leads to deterioration of the device's appearance and further affects its performance. Especially under unstable conditions or operating conditions, the failure probability at the P / N electrode-epitaxy structure interface increases dramatically, significantly reducing device reliability. Examples of failures at the electrode-epitaxy structure interface under these unstable conditions include, but are not limited to, the following:

[0004] Heating process: P / N electrodes contain a wide range of metal elements such as Al. In particular, metal Al is prone to electromigration and failure in high-temperature processes or continuous high-current heating environments due to its low ion activation energy.

[0005] Thermal fatigue characteristics: LEDs generate heat during operation. Thermal cycling can cause fatigue and cracking of the material on the sidewalls of the electrode edge contour mesa, resulting in poor contact and causing the LED to flicker or fail to light up.

[0006] Interface failure: Poor interface quality between the electrode and the semiconductor material can lead to electron migration, interface layer peeling, or diffusion. Interface failure can severely affect the current path and luminous efficiency of an LED, potentially causing functional loss.

[0007] High current problem: During high-power operation, metal migration may cause short circuits or micro-leakage in the LED chip, resulting in LED failure or reduced efficiency.

[0008] Mechanical stress: During packaging or application, LED chips may be subjected to mechanical pressure or stress, affecting the electrode sidewall interface connection. Mechanical stress may cause the electrode sidewall interface to fracture or fail, thus causing the LED to malfunction. Summary of the Invention

[0009] In view of the deficiencies and defects in the prior art of light-emitting diodes, especially ultraviolet light-emitting diodes, caused by interface defects in electrodes and epitaxial structures, resulting in poor device yield and reliability, the present invention provides a light-emitting diode and a light-emitting device to solve one or more of the above-mentioned problems.

[0010] One embodiment of this application provides a light-emitting diode, which includes at least:

[0011] A semiconductor epitaxial stack includes a first semiconductor layer, an active layer, and a second semiconductor layer stacked sequentially; the semiconductor epitaxial stack has a first mesa and a second mesa, the surface of the first mesa is the exposed first semiconductor layer, the surface of the second mesa is the second semiconductor layer, the first mesa is lower than the second mesa and is disposed around the second mesa;

[0012] The electrode structure includes a first electrode formed on the surface of the first mesa and electrically connected to the first semiconductor layer, and a second electrode formed on the surface of the second mesa and electrically connected to the second semiconductor layer.

[0013] The first insulating layer includes a first portion and a second portion. The first portion is disposed around the first electrode on the surface of the first mesa and forms a closed structure. The second portion covers a portion of the sidewall and a portion of the surface of the second mesa. The second portion covers at least the exposed active layer on the sidewall of the second mesa and forms a closed structure.

[0014] A second insulating layer covers the first insulating layer and the surface and sidewalls of the semiconductor epitaxial stack other than the electrode structure.

[0015] Another embodiment of this application provides a light-emitting device, which includes a circuit board and a light-emitting element disposed on the circuit board, wherein the light-emitting element includes the light-emitting diode provided in this application.

[0016] As described above, the light-emitting diode and light-emitting device of this application have the following beneficial effects:

[0017] The light-emitting diode (LED) of this application has a first insulating layer. A first portion of the first insulating layer surrounds a first electrode, and a second portion surrounds the sidewall between the second mesa and the first mesa, as well as a portion of the surface of the second mesa. The first insulating layer forms a duckbill-like structure around the first and second electrodes, respectively. This structure effectively prevents the diffusion of metal elements from the electrodes into the semiconductor epitaxial stack or to the sidewalls of the semiconductor epitaxial stack. Furthermore, the first insulating layer also prevents the edge of the metal electrode from directly contacting the semiconductor epitaxial stack, avoiding metal-epitaxy interface problems and effectively suppressing the migration and failure of metal elements. The first insulating layer forms a wrapping structure around the sidewalls of the semiconductor epitaxial stack, working synergistically with the second insulating layer to further block impurities such as water vapor and electrolyte ions, helping to improve the brightness of the LED and reduce light decay. Furthermore, the formation position of the first insulating layer can be adjusted to passivate and clamp the boundaries of the metal electrode or ITO contact material to improve yield. By adjusting the thickness of the first insulating layer, the light path of the LED can be adjusted, optimizing the brightness of the LED and thus improving luminous efficiency. Attached Figure Description

[0018] Figure 1 The diagram shows a schematic representation of the structure of a light-emitting diode (LED) in the prior art.

[0019] Figure 2a The diagram shown is a top view of the light-emitting diode provided in Embodiment 1 of the present invention.

[0020] Figure 2b Displayed as along Figure 2a The diagram shows a cross-sectional view along the AA direction.

[0021] Figure 2c The diagram shown is a top view of an optional embodiment of the light-emitting diode provided in Embodiment 1 of the present invention.

[0022] Figure 3 Shown as an optional embodiment along Figure 2c The diagram shows a cross-sectional view along the AA direction.

[0023] Figure 4 Shown as another alternative embodiment along Figure 2c A schematic diagram of the cross-sectional structure along the AA direction.

[0024] Figure 5 This shows a top view of the light-emitting diode provided in Embodiment 2 of the present invention.

[0025] Figure 6 Shown as an optional embodiment along Figure 5 The diagram shows a cross-sectional view along the AA direction.

[0026] Figure 7 Shown as another alternative embodiment along Figure 5 The diagram shows a cross-sectional view along the AA direction.

[0027] Figure 8 Shown as another alternative embodiment along Figure 5 The diagram shows a cross-sectional view along the AA direction.

[0028] Figure 9 Shown as another alternative embodiment along Figure 5 The diagram shows a cross-sectional view along the AA direction.

[0029] Figure 10 Displayed as Figure 8 A magnified view of the structure at point C in the middle rectangle.

[0030] Figure 11 show Figure 1 The diagram shows a partially enlarged structural schematic of the rectangular frame C1 of the prior art light-emitting diode.

[0031] Figure 12 This shows a top view of the light-emitting diode provided in Embodiment 3 of the present invention.

[0032] Figure 13 Shown as an optional embodiment along Figure 12 The diagram shows a cross-sectional view along the AA direction.

[0033] Figure 14 Shown as another alternative embodiment along Figure 12 The diagram shows a cross-sectional view along the AA direction.

[0034] Figures 15-16 The graph shows a comparison of individual yield rates of light-emitting diodes from different embodiments of this application.

[0035] Figure 17 The diagram shown is a schematic diagram of the light-emitting device provided in Embodiment 4 of the present invention.

[0036] Component designation explanation

[0037] 11-1, N-type semiconductor layer; 11-2, active layer; 11-3, P-type semiconductor layer; 12, first electrode; 13, second electrode; 14, insulating layer.

[0038] 100, Light-emitting diode; 110, Substrate; 111, Front side; 112, Back side; 120, Semiconductor epitaxial stack; 1201, First mesa; 1202, Second mesa; 121, First semiconductor layer; 122, Active layer; 123, Second semiconductor layer; 124, Transparent conductive layer; 130, First insulating layer; 131, First portion; 132, Second portion; 140, Second insulating layer; 151, First electrode; 1511, Connecting electrode; 1512, Pad; 152, Second electrode.

[0039] 200, Light-emitting device; 201, Circuit board; 202, Light-emitting unit. Detailed Implementation

[0040] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0041] like Figure 1 As shown, in the prior art, an ultraviolet light-emitting diode includes an epitaxial stack, which includes an N-type semiconductor layer 11-1, an active layer 11-2, and a P-type semiconductor layer 11-3 stacked sequentially. A mesa exposing the N-type semiconductor layer 11-1 is formed by etching the P-type semiconductor layer 11-3 and the active layer 11-2. A first electrode 12 electrically connected to the N-type semiconductor layer 11-1 is formed on the mesa, and a second electrode 13 electrically connected to the P-type semiconductor layer 11-3 is formed above the P-type semiconductor layer 11-3. An insulating layer 14 covers the exposed surface and sidewalls of the epitaxial stack and encapsulates the sidewalls of the first electrode 12 and the second electrode 13. Figure 1 As shown, in the aforementioned light-emitting diode (LED), the first electrode 12 and the second electrode 13 are in contact with the epitaxial stack. Due to the relatively thin deposition thickness of the electrode sidewall material, the probability of migration failure at the interface between the electrode sidewall and the epitaxial stack is greatly increased, causing a deterioration in the appearance of the LED and further affecting its performance. Especially under unstable factors or operating conditions, the failure probability at the interface between the P / N electrode and the epitaxial structure increases significantly, resulting in a substantial decrease in the reliability of the LED.

[0042] To address the aforementioned deficiencies of existing light-emitting diodes (LEDs), one embodiment of this application provides an LED comprising at least:

[0043] A semiconductor epitaxial stack includes a first semiconductor layer, an active layer, and a second semiconductor layer stacked sequentially; the semiconductor epitaxial stack has a first mesa and a second mesa, the surface of the first mesa is the exposed first semiconductor layer, the surface of the second mesa is the second semiconductor layer, the first mesa is lower than the second mesa and is disposed around the second mesa;

[0044] The electrode structure includes a first electrode formed on the surface of the first mesa and electrically connected to the first semiconductor layer, and a second electrode formed on the surface of the second mesa and electrically connected to the second semiconductor layer.

[0045] The first insulating layer includes a first portion and a second portion. The first portion is disposed around the first electrode on the surface of the first mesa and forms a closed structure. The second portion covers a portion of the sidewall and a portion of the surface of the second mesa. The second portion covers at least the exposed active layer on the sidewall of the second mesa and forms a closed structure.

[0046] A second insulating layer covers the first insulating layer and the surface and sidewalls of the semiconductor epitaxial stack other than the electrode structure.

[0047] The first insulating layer creates a duckbill-like structure around the first and second portions of the semiconductor epitaxial stack, effectively preventing the diffusion of metal elements from the electrodes into the semiconductor epitaxial stack or to its sidewalls. Furthermore, the first insulating layer prevents direct contact between the edges of the metal electrodes and the semiconductor epitaxial stack, avoiding metal-epitaxy interface problems and effectively suppressing metal element migration and failure. The first insulating layer forms a wrapping structure around the sidewalls of the semiconductor epitaxial stack, working synergistically with the second insulating layer to further block impurities such as water vapor and electrolyte ions, contributing to improved brightness of the LED and reduced light decay.

[0048] Optionally, the second portion extends from the sidewall of the second countertop to the surface of the first countertop.

[0049] The second part extends to the surface of the first countertop and forms a protective layer on the sidewalls of the second countertop and the surface portion of the first countertop, further preventing the diffusion of metal elements along the sidewalls.

[0050] Optionally, the second portion extends below the first electrode and projects onto the plane where the first platform is located, and the projection of the second portion onto the plane where the first platform is located overlaps with the projection of the first electrode.

[0051] Optionally, the first portion extends below the first electrode and is projected onto the plane where the first platform is located. The projection of the first portion overlaps with the projection of the first electrode, but the projection of the first portion and the projection of the second portion do not overlap.

[0052] The first part and the second part extend below the first electrode, such that the edge of the first electrode and the first semiconductor layer of the first mesa are separated by the first insulating layer, which effectively prevents the metal in the first electrode from diffusing into the first semiconductor layer, while ensuring that the middle part of the first electrode is electrically connected to the first semiconductor layer, which is beneficial to improving the reliability of the light-emitting diode.

[0053] Optionally, the second portion extends below the second electrode and projects onto the plane where the second platform is located, and the projection of the second portion onto the plane where the second platform is located overlaps with the projection of the second electrode.

[0054] Optionally, the light-emitting diode further includes a transparent conductive layer located on the surface of the second platform, and the second electrode is located above the transparent conductive layer; when projected onto the plane where the first platform is located, the projection of the second electrode is located within the projection range of the transparent conductive layer.

[0055] Optionally, the second portion located on the second platform is located below the transparent conductive layer, or between the second electrode and the transparent conductive layer.

[0056] The first insulating layer extends below the second electrode. Whether the first insulating layer is located between the transparent conductive layer and the second electrode, or between the transparent conductive layer and the second semiconductor layer, it can prevent the second electrode from migrating to the outline boundary region of the transparent conductive layer and entering the second semiconductor layer. In other words, it blocks the path of the second electrode migrating from the outline boundary region of the transparent conductive layer into the interface between the semiconductor epitaxial layers. Therefore, it can effectively prevent the diffusion of metal elements in the electrode into the semiconductor epitaxial layer, avoid defects such as leakage and failure of the light-emitting diode caused by metal diffusion, and improve the reliability of the device.

[0057] Optionally, the projection is made on the plane where the second platform is located, and the projection outline of the second portion on the second platform is located between the projection outline of the transparent conductive layer and the projection outline of the second electrode.

[0058] Optionally, the second portion located on the second platform is located below the transparent conductive layer or above the transparent conductive layer.

[0059] The above design of the first insulating layer can prevent the second electrode from migrating to the outline boundary region of the transparent conductive layer and entering the second semiconductor layer. In other words, it blocks the path of the second electrode migrating to the outline boundary region of the transparent conductive layer and entering the interface between the semiconductor epitaxial stack. Therefore, it can effectively prevent the diffusion of metal elements in the electrode into the semiconductor epitaxial stack, avoid defects such as leakage and failure of the light-emitting diode caused by metal diffusion, and improve the reliability of the device.

[0060] Optionally, the projected outline of the second portion located on the second platform is outside the projected outline of the transparent conductive layer.

[0061] The first insulating layer wraps around the sidewall of the second platform, which can effectively prevent the migration or diffusion of metal to the sidewall; at the same time, it helps to block impurities such as water vapor and electrolyte ions from penetrating from the sidewall, which helps to improve the reliability of the light-emitting diode.

[0062] Optionally, the first electrode includes a connecting electrode located on the surface of the first mesa and an electrode pad located on the connecting electrode. The projection of the connecting electrode is located on the plane where the first mesa is located, and the projection of the connecting electrode is located within the projection range of the electrode pad. The projection outline of the first part is located between the projection outline of the connecting electrode and the projection outline of the electrode pad.

[0063] The design of the first part, on the one hand, can block the interface between the pad electrode and the first semiconductor layer, preventing the migration of metal elements into the first semiconductor layer; on the other hand, it can ensure the electrical connection between the electrode pad and the connecting electrode, ensuring that the electrical performance of the light-emitting diode is not affected.

[0064] The thickness of the first insulating layer ensures good uniformity on the exposed surface of the semiconductor epitaxial stack, especially on the sidewalls. When the first insulating layer is formed under the electrode structure or the transparent conductive layer, it does not affect the coverage uniformity and continuity of the electrode structure or the transparent conductive layer.

[0065] Optionally, the second insulating layer covers the edge regions of the first electrode and the second electrode, and the thickness of the second insulating layer is greater than the thickness of the first insulating layer.

[0066] The second insulating layer provides good protection for the LED, isolating it from the outside world and improving its reliability.

[0067] Optionally, the sidewall of the first insulating layer is an inclined sidewall, and the angle between the sidewall of the first insulating layer and the plane where the first table is located is between 50° and 70°.

[0068] The sidewalls of the first insulating layer are formed as inclined sidewalls with the aforementioned included angle. When the first insulating layer is formed below the electrode structure or the transparent conductive layer, this sidewall facilitates the adhesion of the metal material forming the electrode structure and the transparent conductive oxide forming the transparent conductive layer, improving adhesion uniformity and reliability. Furthermore, when the electrode structure is formed above the first insulating layer, this sidewall helps improve the sidewall morphology of the electrode structure and helps prevent the migration of metal into the semiconductor stack.

[0069] Another embodiment of the present invention provides a light-emitting device, which includes a circuit board and a light-emitting element disposed on the circuit board, the light-emitting element including the light-emitting diode provided in this application. This light-emitting device includes the light-emitting diode of this application, and therefore can achieve good light extraction efficiency and brightness.

[0070] Example 1

[0071] This embodiment provides a light-emitting diode, such as Figure 2a and Figure 2b As shown, the light-emitting diode 100 includes at least a semiconductor epitaxial stack 120, a first insulating layer 130, an electrode structure, and a second insulating layer 140. The aforementioned semiconductor epitaxial stack 120 comprises a first semiconductor layer 121, an active layer 122, and a second semiconductor layer 123 stacked sequentially. Referring also to… Figure 3 The light-emitting diode 100 also includes a substrate 110, which has a front side 111 and a back side 112, and a semiconductor epitaxial stack 120 is located on the front side 111 of the substrate 110.

[0072] The substrate 110 may be made of materials selected from sapphire (Al2O3), SiC, GaAs, GaN, ZnO, Si, GaP, InP, and Ge, but is not limited thereto. The substrate 110 may be a transparent substrate capable of transmitting light in the ultraviolet wavelength band, such as a sapphire substrate.

[0073] The semiconductor epitaxial stack 120 in this embodiment can be any semiconductor epitaxial stack 120 capable of radiating light under voltage. In this embodiment, the semiconductor epitaxial stack 120 can output light with an ultraviolet wavelength range. For example, the light-emitting structure can output light in the near-ultraviolet wavelength band (UV-A), the far-ultraviolet wavelength band (UV-B), or the deep-ultraviolet wavelength band (UV-C). Exemplarily, the near-ultraviolet wavelength band (UV-A) light can have a peak wavelength in the range of 320nm to 420nm, the far-ultraviolet wavelength band (UV-B) light can have a peak wavelength in the range of 280nm to 320nm, and the deep-ultraviolet wavelength band (UV-C) light can have a peak wavelength in the range of 100nm to 280nm.

[0074] When the semiconductor epitaxial stack 120 emits light in the ultraviolet wavelength band, each semiconductor layer of the light-emitting structure may include In containing aluminum (Al). x1 Al y1 Ga 1-x1-y1 N (0 ≤ x1 ≤ 1, 0 < y1 ≤ 1, 0 ≤ x1 + y1 ≤ 1) material. Among them, the Al component can be represented by the ratio of the total atomic weight including the atomic weights of In, Ga, and Al to the atomic weight of Al. For example, when the Al component accounts for 40%, the Ga component in Al 0.4 Ga 0.6 N can account for 60%.

[0075] The first semiconductor layer 121 in the semiconductor epitaxial stack 120 can be realized by a compound semiconductor such as a III-V group or a II-VI group, and can be doped with a first dopant. The first semiconductor layer 121 can be a semiconductor material with an empirical formula of In x1 Al y1 Ga 1-x1-y1 N (0 ≤ x1 ≤ 1, < y1 ≤ 1, 0 ≤ x1 + y1 ≤ 1), and can be, for example, a material selected from AlGaN, AlN, InAlGaN, etc. The first dopant can be an N-type dopant such as Si, Ge, Sn, Se, Te. When the first dopant is an N-type dopant, the first semiconductor layer 121 doped with the first dopant is an N-type semiconductor layer.

[0076] The active layer 122 is disposed between the first semiconductor layer 121 and the second semiconductor layer 123. The active layer 122 is a layer where electrons (or holes) injected through the first semiconductor layer 121 meet holes (or electrons) injected through the second semiconductor layer 123. As electrons and holes recombine and jump to a lower energy level, light with an ultraviolet wavelength can be generated in the active layer 122. The active layer 122 can have a structure selected from a single-well structure, a multi-well structure, a single quantum well structure, a multi-quantum well (Multi Quantum Well, MQW) structure, a quantum dot structure, or a quantum wire structure, but is not limited thereto.

[0077] The active layer 122 can include a plurality of well layers and barrier layers. The well layers and barrier layers can have an empirical formula of In x2 Al y2 Ga 1-x2-y2 N (0 ≤ x2 ≤ 1, 0 < y2 ≤ 1, 0 ≤ x2 + y2 ≤ 1). The aluminum component of the well layer can vary according to the emission light wavelength. As the aluminum component increases, the wavelength of the light emitted from the well layer can become smaller.

[0078] The second semiconductor layer 123 is formed on the active layer 122 and can be a compound semiconductor such as a Group III-V or Group II-VI compound semiconductor, and the second semiconductor layer 123 can be doped with a second dopant. The second semiconductor layer 123 can be a semiconductor material having an empirical formula of In x5 Al y2 Ga 1-x5-y2 N (0 ≤ x5 ≤ 1, 0 < y2 ≤ 1, 0 ≤ x5 + y2 ≤ 1), or can be a material selected from AlInN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, Ba, etc., the second semiconductor layer 123 doped with the second dopant is a p-type semiconductor layer.

[0079] Although not shown, it can be understood that an electron blocking layer (EBL) or the like can be provided between the active layer 122 and the second semiconductor layer 123. The electron blocking layer, as a confinement layer of the active layer 122, can reduce the leakage of electrons.

[0080] Referring to Figure 2b , the semiconductor epitaxial stack 120 includes a first mesa 1201 and a second mesa 1202. The first mesa 1201 is formed by removing a portion of the active layer 122 and the second semiconductor layer 123 through mesa etching to expose the first semiconductor layer 121, and the unetched semiconductor epitaxial stack 120 forms the second mesa 1202, and the second mesa 1202 is the light-emitting region of the light-emitting diode 100. Referring also to Figure 2b , the first mesa 1201 is disposed to surround the second mesa 1202.

[0081] Referring again to Figure 2a , the light-emitting diode 100 of the present embodiment further includes an electrode structure, and the electrode structure includes a first electrode 151 formed above the first mesa 1201 and electrically connected to the first semiconductor layer 121 and a second electrode 152 formed on the surface of the second mesa 1202 and electrically connected to the second semiconductor layer 123. The second electrode 152 is located above the transparent conductive layer 124. The first electrode 151 further includes a connection electrode 1511 connected to the first semiconductor layer 121 above the first mesa 1201, and an electrode pad 1512 located above the connection electrode 1511. Further, as Figure 2aAs shown, the aforementioned connecting electrode 1511 forms a closed structure around and spaced apart from the second mesa 1202 on the surface extension of the first mesa 1201. The connecting electrode 1511 forms an ohmic contact with the first semiconductor layer 121 to improve the current diffusion effect and uniformity on one side of the first semiconductor layer 121. Electrode pads 1512 are formed in a portion of the first mesa 1201 to facilitate subsequent electrical connection with the outside world.

[0082] In alternative embodiments, the same applies. Figure 2a and Figure 2b As shown, the light-emitting diode 100 of this embodiment has a first insulating layer 130, which includes a first portion 131 and a second portion 132. The first portion 131 is formed on the first mesa 1201, and the second portion 132 is formed on the sidewall and part of the surface of the second mesa 1202. Specifically, the second portion 132 covers the edge region of the second mesa 1202 that is not covered by the second electrode 152. The first insulating layer 130 can be an insulating oxide, an insulating nitride, etc. For example, it can be one or more of SiO2, Si3N4, Al2O3, TiO2, ZnO, HfO2, etc. The first insulating layer 130 can be a single structure or a multilayer structure. Its thickness is between Furthermore, given For reference Figure 10 The sidewall of the first insulating layer 130 is an inclined sidewall, and the angle α between the sidewall of the first insulating layer 130 and the plane where the first platform 1201 is located is between 50° and 70°.

[0083] In one optional embodiment of this example, refer to Figure 2c and Figure 3 The light-emitting diode 100 also includes a transparent conductive layer 124, which is formed above the second mesa 1202. Specifically, the transparent conductive layer 124 can completely cover the second semiconductor layer 123 exposed on the second mesa 1202, or it can partially cover the second semiconductor layer 123. Figure 3As shown, in this embodiment, the transparent conductive layer 124 covers a portion of the second semiconductor layer 123. There is a certain distance between the edge of the transparent conductive layer 124 and the edge of the second semiconductor layer 123; that is, the transparent conductive layer 124 is not covered above the second semiconductor layer 123 at the edge of the second mesa 1202. The transparent conductive layer 124 is formed of a transparent conductive material, including but not limited to indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), indium tungsten oxide (IWO), zinc oxide (ZnO), gallium phosphide (GaP), indium cerium oxide (ICO), indium tungsten oxide (IWO), indium titanium oxide (ITiO), indium zinc oxide (IZO), indium gallium oxide (IGO), gallium aluminum zinc oxide (GAZO), or combinations of the above materials.

[0084] As shown in Figure 3, in this optional embodiment, the first portion 131 is formed around the periphery of the first mesa 1201, i.e., outside the first electrode 151, surrounding the first electrode 151 and spaced apart from it. The second portion 132 is formed on the sidewall of the second mesa 1202 and extends from the sidewall to cover the edge region of the second mesa 1202, specifically, covering the edge region of the second mesa 1202 not covered by the transparent conductive layer 124. Figure 2c As shown, when projected onto the plane where the second platform 1201 is located, the projection E4 of the second electrode 152 lies within the range of the projection E3 of the transparent conductive layer 124, while the projection outline E52 of the second portion 132 of the first insulating layer 130 on the second platform 1202 lies outside the projection outline E3 of the transparent conductive layer 124. When projected onto the plane where the first platform 1201 is located, the projection E1 of the first portion 131 does not overlap with the projection E51 of the first electrode 151.

[0085] In one optional embodiment of this example, such as Figure 4 As shown, the second portion 132 extends from the sidewall of the second platform 1202 toward the first platform 1201, reaching the periphery of the first electrode 151, and further, it can be disposed adjacent to the first electrode 151. This arrangement can further protect the sidewall of the second platform 1202.

[0086] The aforementioned arrangement of the first insulating layer 130 causes the first portion 131 and the second portion 132 to form a duckbill-like structure around the first electrode 151 and the second electrode 152, respectively. In particular, the second portion 132 effectively prevents the diffusion of metal elements from the electrodes into the semiconductor epitaxial stack 120 or to the sidewalls of the semiconductor epitaxial stack 120. Furthermore, the first insulating layer 130 also prevents the edges of the metal electrodes from directly contacting the semiconductor epitaxial stack 120, avoiding metal-epitaxy interface problems and effectively suppressing the migration and failure of metal elements. The first insulating layer 130 forms a wrapping structure around the sidewalls of the semiconductor epitaxial stack 120, working synergistically with the subsequently formed second insulating layer to further block impurities such as water vapor and electrolyte ions, helping to improve the brightness of the light-emitting diode and reduce light decay of the device.

[0087] Refer again Figure 2b and Figure 3 The light-emitting diode 100 further includes a second insulating layer 140, which covers the first insulating layer 130 and the surface and sidewalls of the semiconductor epitaxial stack 120 excluding the electrode structure. The second insulating layer 140 can be SiO2, Si3N4, Al2O3, TiO2, ZnO, HfO2, etc. Its thickness is much greater than that of the first insulating layer 130; for example, the thickness of the second insulating layer 140 is between 0.5 μm and 5 μm, and more specifically, between 1 μm and 3 μm. The second insulating layer 140 and the first insulating layer 130 can be made of the same material, thereby increasing their adhesion and improving the reliability of the light-emitting diode. It is understood that an opening 1401 is formed above the second insulating layer 140 to expose the first electrode 151 (specifically, pad 1512) and the second electrode 152, and an external pad connecting the first electrode 151 and the second electrode 152 is formed above the second insulating layer 140.

[0088] Example 2

[0089] This embodiment provides a light-emitting diode, such as Figures 5 to 11 As shown, the light-emitting diode 100 also includes at least a semiconductor epitaxial stack 120, a first insulating layer 130, an electrode structure, and a second insulating layer 140. The aforementioned semiconductor epitaxial stack comprises a first semiconductor layer 121, an active layer 122, and a second semiconductor layer 123 stacked sequentially from top to bottom. The similarities to Embodiment 1 will not be repeated, but the differences are:

[0090] like Figure 5As shown, when projected onto the plane of the second mesa 1202, the projection E4 of the second electrode 152 lies within the projection E3 of the transparent conductive layer 124. The projection outline E52 of the second portion 132 of the first insulating layer 130 on the second mesa 1202 lies within the projection outline E3 of the transparent conductive layer 124, and the projection outline E52 of the second portion 132 lies between the projection outline E3 of the transparent conductive layer 124 and the projection outline E4 of the second electrode 152. At this time, the projection outline of the second portion 132 of the first insulating layer 130 extending to the side of the first mesa 1201 can be within the projection E1 of the first mesa 1201 or outside the projection E1 of the first mesa 1201. That is, the second portion 132 can extend onto the first mesa 1201, or it can only cover the sidewall between the second mesa 1202 and the first mesa 1201, without covering the first mesa 1201.

[0091] In one alternative embodiment, such as Figure 6 As shown, the arrangement of the first portion 131 and the arrangement of the second portion 132 near the first platform 1201 are the same as in Embodiment 1. The second portion 132, located above the second platform 1202, extends above the transparent conductive layer 124, covering the edge area of ​​the transparent conductive layer 124 not covered by the second electrode 152, and the second portion 132 is spaced apart from the second electrode 152.

[0092] In another alternative embodiment, such as Figure 7 As shown, with Figure 6 The difference in the structure shown is that the second portion 132 on the second platform 1202 extends below the transparent conductive layer 124, covering the edge portion of the second platform 1202 not covered by the transparent conductive layer 124, as well as the portion of the second platform 1202 covered by the edge of the transparent conductive layer 124.

[0093] The above design of the first insulating layer 130 can prevent the second electrode 152 from migrating to the outline boundary region of the transparent conductive layer 124 and entering the second semiconductor layer 123. That is, it blocks the path of the second electrode 152 migrating to the outline boundary region of the transparent conductive layer 124 and entering the interface between the semiconductor epitaxial stacks 120. Therefore, it can effectively prevent the diffusion of metal elements in the electrode into the semiconductor epitaxial stacks 120, avoid defects such as leakage and failure of the light-emitting diode caused by metal diffusion, and improve the reliability of the device.

[0094] In another optional embodiment of this example, such as Figure 8 and Figure 9As shown, when projected onto the plane where the first platform 1201 is located, the projection of the first portion 131 of the first insulating layer 130 overlaps with the projection of the first electrode 151. The second portion 132 of the first insulating layer 130, extending to the side of the first platform 1201, extends from the sidewall of the second platform 1202 to above the first platform 1201. The projection of the second portion 132 on the plane where the first platform 1201 is located overlaps with the projection of the first electrode 151 on the plane where the first platform 1201 is located. At the same time, the projection of the first portion 131 of the first insulating layer 130 on the plane where the first platform 1201 is located and the projection of the second portion 132 on the plane where the first platform 1201 is located do not overlap on the first platform 1201.

[0095] The first part 131 and the second part 132 extend below the first electrode 151, such that the edge of the first electrode 151 and the first semiconductor layer 121 of the first mesa 1201 are separated by the first insulating layer 130, which effectively prevents the metal in the first electrode 151 from diffusing into the first semiconductor layer 121, while ensuring that the middle part of the first electrode 151 is electrically connected to the first semiconductor layer 121, which is beneficial to improving the reliability of the light-emitting diode.

[0096] Furthermore, such as Figure 8 and Figure 9 As shown, the first portion 131 of the first insulating layer 130 is located below the pad 1512 of the first electrode 151 and is spaced apart from the connecting electrode 1511. Similarly, the second portion 132 is also located on one side of the first mesa 1201 below the pad 1512 of the first electrode 151 and is spaced apart from the connecting electrode 1511.

[0097] like Figure 8 As shown, in one optional embodiment, a second portion 132 of the first insulating layer 130 is formed on one side of the second mesa 1202 above the transparent conductive layer 124 and is spaced apart from the second electrode 152. In another optional embodiment, as... Figure 9 As shown, a second portion 132 of the first insulating layer 130 is formed on one side of the second mesa 1202 below the transparent conductive layer 124.

[0098] like Figure 8 and Figure 9The design of the first insulating layer 130 shown above can prevent the second electrode 152 from migrating to the outline boundary region of the transparent conductive layer 124 and entering the second semiconductor layer 123. That is, it blocks the path of the second electrode 152 migrating to the outline boundary region of the transparent conductive layer 124 and entering the interface between the semiconductor epitaxial stacks 120. Therefore, it can effectively prevent the diffusion of metal elements in the electrode into the semiconductor epitaxial stacks 120, avoid defects such as leakage and failure of the light-emitting diode caused by metal diffusion, and improve the reliability of the device.

[0099] like Figure 10 As shown, taking the first portion 131 above the first mesa 1201 as an example, the sidewall of the first insulating layer 130 is an inclined sidewall, and the angle α between the sidewall of the first insulating layer 130 and the plane where the first mesa 1201 is located is between 50° and 70°, and further, between 55° and 65°. Taking the first portion 131 of the first insulating layer 130 on one side of the first electrode 151 as an example, the inclined sidewall of the first insulating layer 130 is beneficial for improving the sidewall morphology of the pad 1512 of the first electrode 151 formed thereon. Figure 11 As shown, in the prior art, the first electrode 12 is directly formed on the surface of the N-type semiconductor layer 11-1. In this case, a tip 15 is easily formed between the edge of the first electrode 12 and the N-type semiconductor layer 11-1. This tip 15 easily forms a channel for metal in the first electrode 12 to diffuse or migrate into the N-type semiconductor layer 11-1. This metal migration may form a micro-leakage channel, causing current to bypass the light-emitting region (such as a quantum well), inducing leakage current; it may also cause lattice distortion or dislocations. Migrating metal impurities may introduce defects in the epitaxial stack, becoming non-radiative recombination centers for charge carriers, weakening the mechanical strength of the material, and accelerating device aging. Furthermore, metal migration or diffusion may act as donor or acceptor impurities, changing the doping characteristics of the epitaxial stack, affecting the conductivity type of the semiconductor layer (such as n-type or p-type), and thus affecting the device's performance and reliability. In this application, the sidewalls of the first insulating layer 130 are configured so that when forming the pad 1512, a path such as... is not formed above the first semiconductor layer 121. Figure 11 The pointed tip, as shown, blocks the diffusion or migration path of metal. Alternatively, the tip 150 of the pad 1512 may translate along the sidewall of the first insulating layer 130 to the space between the first insulating layer 130 and the second insulating layer 140. In this case, even if metal diffusion and migration occur at the tip 150, it will not enter the first semiconductor layer 121. Therefore, the various defects or risks caused by metal migration or diffusion mentioned above are avoided. It can be seen that the above-mentioned arrangement of the first insulating layer 130 is beneficial to improving the reliability of the device.

[0100] Example 3

[0101] This embodiment provides a light-emitting diode, such as Figures 12 to 14As shown, the light-emitting diode 100 also includes at least a semiconductor epitaxial stack 120, a first insulating layer 130, an electrode structure, and a second insulating layer 140. The aforementioned semiconductor epitaxial stack comprises a first semiconductor layer 121, an active layer 122, and a second semiconductor layer 123 stacked sequentially from top to bottom. The similarities to Embodiment 1 will not be repeated, but the differences are:

[0102] like Figure 12 As shown, the projection of the second electrode 152 onto the plane of the second mesa 1202 is within the range of the projection E4 of the transparent conductive layer 124 onto the plane of the second mesa 1202. The projection outline E52 of the second portion 132 of the first insulating layer 130 on the plane of the second mesa 1202 is within the range of the projection outline E4 of the second electrode 152 onto the plane of the second mesa 1202. The second portion 132 extends from the sidewall of the second mesa 1202 to above the first mesa 1201, and is located below the pad 1512 of the first electrode 151, spaced apart from the connecting electrode 1511. Similarly, the first part 131 also extends below the pad 1512 and is spaced apart from the connecting electrode 1511. That is, the projection of the first part 131 on the plane where the first platform 1201 is located does not overlap with the projection of the second part 132 on the plane where the first platform 1210 is located.

[0103] In one alternative embodiment, such as Figure 13 As shown, the second portion 132 located on the second platform 1202 is above the transparent conductive layer 124, and a portion of it extends between the transparent conductive layer 124 and the second electrode 152.

[0104] In another alternative embodiment, such as Figure 14 As shown, the second portion 132 located on the second mesa 1202 is located below the transparent conductive layer 124, and a portion of it extends to the part of the transparent conductive layer 124 covered by the second electrode 152. That is, the projection outline E52 of the second portion 132 of the first insulating layer 130 on the second mesa 1202 is located within the projection outline E4 of the second electrode 152 on the plane where the second mesa 1202 is located.

[0105] The first insulating layer 130 extends below the second electrode 152. Whether the first insulating layer 130 is located between the transparent conductive layer 124 and the second electrode 152, or between the transparent conductive layer 124 and the second semiconductor layer 123, it can prevent the second electrode 152 from migrating to the outline boundary region of the transparent conductive layer 124 and entering the second semiconductor layer 123. In other words, it blocks the path of the second electrode 152 migrating to the outline boundary region of the transparent conductive layer 124 and entering the interface between the semiconductor epitaxial stacks 120. Therefore, it can effectively prevent the diffusion of metal elements in the electrode into the semiconductor epitaxial stacks 120, avoid defects such as leakage and failure of the light-emitting diode caused by metal diffusion, and improve the reliability of the device.

[0106] To verify the improvement in light emission between the LED of this application and existing LEDs, Figure 3 , Figure 6 , Figure 13 ,as well as Figure 7 , Figure 14 The yield of the proposed LED was tested and compared with that of existing LEDs. The existing LEDs were used as comparative examples. Figure 3 The LED shown is sample 1. Figure 7 The LED shown is sample 2. Figure 14 The LED shown is sample 3. Figure 6 The LED shown is sample 4. Figure 13 The LED shown is sample 5. The thickness of the first insulating layer 130 in each sample and the test results are shown in Tables 1 and 2 below. The comparison results are as follows: Figure 15 and Figure 16 As shown.

[0107] Table 1. Results of reverse current (IR) single-item yield test for each sample.

[0108]

[0109] Table 2. Voltage values ​​of each sample under minute current. VF4 single-item yield test results.

[0110]

[0111] From Tables 1 and 2 above, the reverse current IR is less than 0.1μA, and VF4 is between 3V and 5V at a test current of 1μA. From Tables 1 and 2 above, and the appendix... Figure 15 and Figure 16 It can be seen that, compared to the comparative example, the thickness of the first insulating layer 130 is... The IR yield of sample 3 was improved by 2.4%, and the VF4 yield was improved by 2.5%. Compared to the comparative example, the thickness of the first insulating layer 130 was... The IR yield and VF4 yield of samples 4 and 5 can be improved by more than 1%.

[0112] Example 4

[0113] This embodiment provides a light-emitting device, such as... Figure 17 As shown, the light-emitting device 200 includes a circuit board 201 and at least one light-emitting unit 202 fixed to the circuit board 201. The light-emitting unit 202 includes any one or more light-emitting diodes provided in Embodiments 1 to 3 of this application. Because the light-emitting device includes the light-emitting diodes provided in Embodiments 1 to 3, it has good light extraction efficiency and better reliability.

[0114] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A light-emitting diode, characterized in that, At least including: A semiconductor epitaxial stack includes a first semiconductor layer, an active layer, and a second semiconductor layer stacked sequentially; the semiconductor epitaxial stack has a first mesa and a second mesa, the surface of the first mesa is the exposed first semiconductor layer, the surface of the second mesa is the second semiconductor layer, the first mesa is lower than the second mesa and is disposed around the second mesa; The electrode structure includes a first electrode formed on the surface of the first mesa and electrically connected to the first semiconductor layer, and a second electrode formed on the surface of the second mesa and electrically connected to the second semiconductor layer. The first insulating layer includes a first portion and a second portion. The first portion is disposed around the first electrode on the surface of the first mesa and forms a closed structure. The second portion covers a portion of the sidewall and a portion of the surface of the second mesa. The second portion covers at least the exposed active layer on the sidewall of the second mesa and forms a closed structure. A second insulating layer covers the first insulating layer and the surface and sidewalls of the semiconductor epitaxial stack other than the electrode structure.

2. The light-emitting diode according to claim 1, characterized in that, The second portion extends from the side wall of the second countertop to the surface of the first countertop.

3. The light-emitting diode according to claim 2, characterized in that, The second part extends below the first electrode and projects onto the plane where the first platform is located. The projection of the second part onto the plane where the first platform is located overlaps with the projection of the first electrode. The projections of the first part and the second part do not overlap.

4. The light-emitting diode according to claim 1, characterized in that, The first portion extends below the first electrode and projects onto the plane where the first platform is located, with the projection of the first portion overlapping the projection of the first electrode.

5. The light-emitting diode according to claim 1 or 3, characterized in that, The second portion extends below the second electrode and projects onto the plane where the second platform is located. The projection of the second portion onto the plane where the second platform is located overlaps with the projection of the second electrode.

6. The light-emitting diode according to claim 5, characterized in that, It also includes a transparent conductive layer located on the surface of the second platform, with the second electrode located above the transparent conductive layer; the projection of the second electrode onto the plane where the first platform is located is within the projection range of the transparent conductive layer.

7. The light-emitting diode according to claim 6, characterized in that, The second portion located on the second platform is located below the transparent conductive layer or between the second electrode and the transparent conductive layer.

8. The light-emitting diode according to claim 6, characterized in that, Projected onto the plane where the second platform is located, the projected outline of the second portion on the second platform lies between the projected outline of the transparent conductive layer and the projected outline of the second electrode.

9. The light-emitting diode according to claim 8, characterized in that, The second portion located on the second platform is either below or above the transparent conductive layer.

10. The light-emitting diode according to claim 7, characterized in that, The projected outline of the second portion located on the second platform is outside the projected outline of the transparent conductive layer.

11. The light-emitting diode according to claim 1, characterized in that, The first electrode includes a connecting electrode located on the surface of the first mesa and an electrode pad located above the connecting electrode. The projection of the connecting electrode is located on the plane of the first mesa, and the projection of the connecting electrode is located within the projection range of the electrode pad. The projection outline of the first part is located between the projection outline of the connecting electrode and the projection outline of the electrode pad.

12. The light-emitting diode according to claim 1, characterized in that, The second insulating layer covers the edge regions of the first electrode and the second electrode, and the thickness of the second insulating layer is greater than the thickness of the first insulating layer.

13. The light-emitting diode according to claim 1, characterized in that, The sidewall of the first insulating layer is an inclined sidewall, and the angle between the sidewall of the first insulating layer and the plane on which the first platform is located is between 50° and 70°.

14. A light-emitting device, characterized in that, It includes a circuit board and a light-emitting element disposed on the circuit board, wherein the light-emitting element comprises a light-emitting diode as described in any one of claims 1 to 13.

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