Light emitting diode and light emitting device

Abstract

The application provides a light emitting diode and a light emitting device. The sidewall of the light emitting diode is an inclined sidewall, which comprises a first section connected with a substrate and a second section connected with the first section, wherein the first section comprises a protruding part protruding outward from the inclined sidewall. The protruding part makes the sidewall of the light emitting diode form a multi-section reflecting surface, which can greatly increase the contact interface area of the light and the sidewall compared with a smooth sidewall with consistent inclination. Meanwhile, the protruding part can provide more reflection paths for light with different propagation directions, avoid light loss caused by a single reflection angle, and guide oblique light and scattered light, which are originally easy to be absorbed, to the light emitting surface of the chip after multiple reflections, thereby significantly improving the sidewall light extraction rate.

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) possess 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, including lighting, signal displays, backlights, automotive lights, and large-screen displays. These applications have also placed higher demands on LED brightness and chip size. Among them, flip-chip (FC) LED chips, due to their higher brightness and superior heat dissipation performance, are gradually replacing conventional chips and becoming the mainstream product in this field.

[0003] Currently, the FC LED chips used in high-power, high-efficiency lighting are mainly based on silver (Ag) structures. Early common structures included pure silver (Ag) structures and silicon dioxide + silver (SiO2 + Ag) structures. These traditional structures are relatively simple in design, but they have inherent defects in terms of low brightness and luminous efficacy, making it difficult to meet the current lighting industry's demand for higher luminous efficacy and brighter output.

[0004] To improve the brightness performance of LED chips, the industry has gradually developed composite substrate epitaxy technology and composite structures of distributed Bragg mirrors + silver (DBR+Ag). By optimizing the light reflection path and substrate performance, the luminous efficiency of the chips has been improved to some extent. However, existing LED chips based on composite substrate epitaxy and DBR+Ag structures still face bottlenecks in brightness improvement and cannot fully unleash their performance potential in high-power lighting scenarios. Therefore, a new structural design is urgently needed to further break through the limitations of existing technologies and achieve a significant increase in the brightness of FC LED chips. Summary of the Invention

[0005] In view of the defects and deficiencies of existing light-emitting diodes, especially FC light-emitting diodes, in terms of light extraction efficiency, the present invention provides a light-emitting diode and a light-emitting device to solve one or more of the above-mentioned problems.

[0006] One embodiment of this application provides a light-emitting diode, which includes at least a substrate and a semiconductor epitaxial stack, the substrate having a front side and a back side disposed opposite to each other; the semiconductor epitaxial stack is located on the front side; wherein the sidewall of the light-emitting diode is an inclined sidewall, the inclined sidewall including a first segment connected to the substrate and a second segment connected to the first segment, wherein the first segment includes a protrusion bulging outward from the inclined sidewall.

[0007] 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.

[0008] As described above, the light-emitting diode and light-emitting device of this application have the following beneficial effects: The light-emitting diode (LED) of this application has a sloping sidewall, which includes a first segment connected to a substrate and a second segment connected to the first segment. The first segment includes a protrusion extending outward from the sloping sidewall. This protrusion creates a multi-segmented reflective surface on the LED sidewall, significantly increasing the contact area between light and the sidewall compared to a smooth sidewall with a uniform slope. Simultaneously, the protrusion provides more reflection paths for light rays propagating in different directions, avoiding light loss caused by a single reflection angle. This allows obliquely incident and scattered light rays, which are easily absorbed, to be guided to the chip's light-emitting surface after multiple reflections, significantly improving the sidewall light extraction rate. Attached Figure Description

[0009] Figure 1 The diagram shown is a top view of the light-emitting diode provided in Embodiment 1 of the present invention, in which only a portion of the projected outline of the structure is shown.

[0010] Figure 2 Displayed as along Figure 1 Schematic diagram of the cross-sectional structure along line AA.

[0011] Figure 3 Displayed as Figure 2 A partially enlarged schematic diagram of the sidewall portion of the light-emitting diode in section C.

[0012] Figure 4 Displayed as Figure 2 A partial magnification of the substrate portion of the light-emitting diode in section C.

[0013] Figure 5 The diagram shown is a schematic diagram of the structure of a light-emitting diode provided in Embodiment 2 of the present invention.

[0014] Figure 6 Figure 5 A partially enlarged schematic diagram of the sidewall portion of the light-emitting diode in section C.

[0015] Figure 7 The diagram shown is a schematic diagram of the structure of a light-emitting diode provided in Embodiment 3 of the present invention.

[0016] Figure 8 Figure 7 A partially enlarged schematic diagram of the sidewall portion of the light-emitting diode in section C.

[0017] Figure 9The diagram shown is a schematic diagram of the light-emitting device provided in Embodiment 4 of the present invention.

[0018] Component designation explanation 100. Light-emitting diode; 110. Substrate; 111. Front side; 112. Back side; 113. Raised structure; 1131. First portion; 1132. Second portion; 114. Cutter track; 120. Semiconductor epitaxial stack; 1201. First mesa; 1202. Second mesa; 121. First semiconductor layer; 122. Active layer; 123. Second semiconductor layer; 124. Current blocking layer; 125. Sloping sidewall; 1251. First segment; 1252. Second segment; 12511. First 12512, second protrusion; 12513, connecting portion; 130, transparent conductive layer; 141, first insulating protective layer; 1411, second through hole; 1412, third through hole; 142, second insulating protective layer; 151, insulating reflective layer; 1511, first through hole; 152, metal reflective layer; 161, first electrode; 1611, first connecting electrode; 1612, first pad electrode; 162, second electrode; 1621, second connecting electrode; 1622, second pad electrode.

[0019] 300, Light-emitting device; 301, Circuit board; 302, Light-emitting unit. Detailed Implementation

[0020] 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.

[0021] In existing technologies, FC LED chips used in high-power, high-efficiency lighting are mainly based on silver (Ag) structures, with common structural forms including pure silver (Ag) structures and silicon dioxide + silver (SiO2 + Ag) structures. These traditional structural designs are relatively simple, but they inherently suffer from low brightness and luminous efficacy, making it difficult to meet the current lighting industry's demands for higher luminous efficacy and brighter output. Subsequent developments have focused on composite substrate epitaxy technology and composite structures using distributed Bragg mirrors + silver (DBR + Ag). This structure improves the chip's luminous efficacy to some extent by optimizing the light reflection path and substrate performance. However, existing LED chips based on composite substrate epitaxy and DBR + Ag structures still face bottlenecks in brightness improvement, failing to fully unleash their performance potential in high-power lighting scenarios.

[0022] To address the aforementioned deficiencies of existing light-emitting diodes (LEDs), one embodiment of this application provides an LED that includes at least a substrate and a semiconductor epitaxial stack. The substrate has a front side and a back side disposed opposite to each other. The semiconductor epitaxial stack is located on the front side. The sidewall of the LED is an inclined sidewall, which includes a first segment and a second segment. The first segment is located below the second segment and close to the substrate. The first segment includes an outwardly bulging protrusion.

[0023] The aforementioned protrusions create a multi-segment reflective surface on the sidewall of the LED, significantly increasing the contact area between light and the sidewall compared to a smooth sidewall with a uniform slope. Simultaneously, these protrusions provide more reflection paths for light rays traveling in different directions, avoiding light loss caused by a single reflection angle. This allows obliquely incident and scattered light rays, which are easily absorbed, to be guided to the chip's light-emitting surface after multiple reflections, significantly improving the sidewall light extraction rate.

[0024] Optionally, the angle between the inclined sidewall and the front surface is between 30° and 70°.

[0025] The sloping design of the sidewalls can increase the reflection of light by the sidewalls, which can also increase the light emission effect of the LEDs.

[0026] Optionally, there is a vertical distance D1 between the highest point of the protrusion and the extension line of the second segment of the inclined sidewall, which satisfies: 0.05 μm ≤ D1 ≤ 1 μm.

[0027] The defined vertical distance between the protrusion and the inclined sidewall ensures that the protrusion is neither too high nor too low. If it's too high, the manufacturing process of the LED might become overly complex; if it's too low, it might fail to increase light reflection. Therefore, the aforementioned design of the protrusion increases light reflection without affecting the LED's manufacturing process, thereby enhancing the LED's light emission performance.

[0028] Optionally, the protrusion includes a first protrusion connecting the second segment and a second protrusion connecting the substrate, and the first segment further includes a connecting portion connecting the first protrusion and the second protrusion.

[0029] The aforementioned protrusion configuration allows the LED to form multi-segmented and diverse sidewalls, thereby increasing the light reflection effect and enhancing the light emission effect of the LED.

[0030] Optionally, the substrate is a patterned substrate, and a periodically arranged protrusion structure is formed on one side of the front side, and the first segment of the inclined sidewall includes at least a portion of the sidewall of the protrusion structure.

[0031] The patterned structure of the substrate causes the inclined sidewalls of the light-emitting diode to form protrusions in the parts that come into contact with the patterned structure. These protrusions and the patterned structure of the substrate can work together to increase the light emission effect of the light-emitting diode.

[0032] Optionally, the protrusion structure includes a first portion having the same forming material as the substrate, and a second portion located above the first portion and having a different forming material from the substrate.

[0033] Optionally, the protrusion is located in the region corresponding to the first portion and the second portion.

[0034] The protrusion structure of the substrate consists of two parts with different material compositions. The etching parameters during the protrusion structure formation process can be controlled so that the first part and the second part have different structural features. For example, by controlling the etching parameters when etching the epitaxial layer in the LED manufacturing process, the etching rate of the epitaxial layer is made faster than the etching rate of the substrate. This causes the protrusion structure of the substrate to be exposed from the sidewall of the epitaxial layer after etching, forming the aforementioned protrusion features of the LED sidewall, thereby improving the light emission effect of the LED.

[0035] Optionally, the protrusion is located in the area corresponding to the first portion.

[0036] Optionally, the protrusion structure has the same forming material as the substrate.

[0037] Different types of substrates and different types of patterned structures on the substrates give the aforementioned protrusions on the sidewalls of the light-emitting diode different characteristics. These protrusions can increase the light reflection effect and increase the light emission effect of the light-emitting diode.

[0038] Optionally, the intersection of the first segment and the second segment has a second vertical distance D2 between it and the front side of the substrate, which satisfies: 1 μm ≤ D2 ≤ 5 μm.

[0039] This distance limit ensures that the protrusion has a certain extension length, or that the protrusion forms a significant structure, so as to ensure the light reflection effect and increase the light emission effect of the LED.

[0040] Optionally, the 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 disposed around the second mesa and is lower than the second mesa, and the inclined sidewall is the sidewall between the first mesa and the substrate.

[0041] The light-emitting diode of this application is a flip-chip light-emitting diode, with the substrate side serving as the light-emitting side. Therefore, the inclined sidewall with the protrusion is located at the end closer to the substrate, which is more conducive to reflecting more light and increasing the light-emitting effect.

[0042] Optionally, the sidewalls of the second platform are inclined sidewalls.

[0043] The second platform is designed with an inclined sidewall, which can also increase the reflection of light incident on the sidewall, thus improving the light output efficiency.

[0044] Optionally, the photodiode further includes: An insulating reflective layer is located on the surface of the semiconductor epitaxial stack and at the inclined sidewalls; A metal reflective layer is located above the insulating reflective layer at the second platform, and the metal reflective layer is electrically connected to the second semiconductor layer through a through-hole penetrating the insulating reflective layer; A first insulating protective layer covers the metal reflective layer and the exposed insulating reflective layer.

[0045] The insulating reflective layer and the metal reflective layer work together to form a total reflection system, which reflects as much light as possible and allows it to exit from the light-emitting side.

[0046] Optionally, the photodiode further includes: The second insulating protective layer is located above the first insulating protective layer; The electrode structure includes a first electrode electrically connected to the first semiconductor layer and a second electrode electrically connected to the second semiconductor layer.

[0047] The insulating protective layer provides excellent electrical insulation for the LED, preventing short circuits and other problems; it also protects the LED from moisture, impurities, and other contaminants. The electrode structure enables the LED to connect electrically to the external environment, facilitating its photoelectric conversion.

[0048] 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.

[0049] Example 1

[0050] This embodiment provides a light-emitting diode, such as Figure 1 and Figure 2As shown, the light-emitting diode 100 includes at least a substrate 110 and a semiconductor epitaxial stack 120 formed on the substrate. The semiconductor epitaxial stack 120 includes a first semiconductor layer 121, an active layer 122, and a second semiconductor layer 123 stacked sequentially. Referring also to… Figure 2 The substrate 110 has a front side 111 and a back side 112, and the semiconductor epitaxial stack 120 is located on the front side 111 of the substrate 110.

[0051] The substrate 110 can be made of materials selected from sapphire (Al2O3), SiC, GaAs, GaN, ZnO, Si, GaP, InP, and Ge, but is not limited to these. The substrate 110 is a light-transmitting substrate, such as a sapphire substrate. In this embodiment, the back side 112 of the substrate 110 is the light-emitting side of the light-emitting diode. To increase the epitaxial quality of the semiconductor epitaxial stack 120 and reduce defects such as dislocations, in this embodiment, the front side 111 of the substrate 110 is formed with a patterned structure.

[0052] In this embodiment, as Figure 4 As shown, the front side 111 of the substrate 110 has periodically arranged protrusions 113, which include a first portion 1131 and a second portion 1132 formed above the first portion 1131. In an optional example, the sidewalls of both the first portion 1131 and the second portion 1132 are formed as relatively smooth, arc-shaped sidewalls protruding outwards from the center of the protrusion structure. Furthermore, the first portion 1131 is formed as a frustum structure, and the second portion 1132 is formed as a cone structure. The formation of the protrusions 113 reduces the proportion of the epitaxial surface exposed on the front side 111 of the substrate 110, resulting in a semiconductor epitaxial stack 120 with a relatively low dislocation density, thereby improving the light extraction efficiency. Additionally, the arc-shaped sidewalls of the second portion 1132 allow light radiated from the semiconductor epitaxial stack 120 to be reflected in various directions, resulting in more uniform emitted light.

[0053] As an example, the forming material of the first portion 1131 of the protrusion structure 113 is not the same as that of the second portion 1132. For example, the first portion 1131 is part of the substrate 110 and has the same forming material as the substrate 110, such as Al2O3; while the forming material of the second portion 1132 may be one or more selected from SiO2, Si3N4, ZnO2, Si, SiC, GaAs, Ti3O5, and TiO2. As the first portion 1131 and the second portion 1132 have different forming materials, the etching parameters during the formation process of the protrusion structure 113 can be controlled, so that the first portion 1131 and the second portion 1132 have the above-mentioned different structural features. For example, the second portion 1132 may have outwardly bulging arc-shaped sidewalls.

[0054] 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 near-ultraviolet light (UV-A) with a peak wavelength in the range of 320 nm to 420 nm, far-ultraviolet light (UV-B) with a peak wavelength in the range of 280 nm to 320 nm, or deep ultraviolet light (UV-C) with a peak wavelength in the range of 100 nm to 280 nm; or blue light with a peak wavelength in the range of 440 nm to 470 nm, cyan light with a peak wavelength in the range of 480 nm to 510 nm, green light with a peak wavelength in the range of 510 nm to 570 nm, yellow light with a peak wavelength in the range of 570 nm to 600 nm, orange light with a peak wavelength in the range of 600 nm to 630 nm, or red light with a peak wavelength in the range of 630 nm to 700 nm.

[0055] Each semiconductor layer of the semiconductor epitaxial stack 120 may include an InAlGaN-based material containing aluminum (Al), or an AlGaInP-based material. The Al composition can be expressed as the ratio of the total atomic weight (including In, Ga, and Al atoms) to the Al atomic weight. For example, when the Al composition accounts for 40%, Al... 0.4 Ga 0.6The Ga component in N can account for 60%. The wavelength range of the light emitted by the semiconductor epitaxial stack 120, i.e., the color of the emitted light, can be adjusted by controlling the content of Al and In components. The wavelength range of the light emitted by the semiconductor epitaxial stack 120, i.e., the color of the emitted light, can be precisely controlled by adjusting the content of each element (In, Al, Ga) in its material system: for example, ultraviolet light is mainly achieved by controlling the content of aluminum (Al), which requires ensuring that the material contains a certain amount of Al component; blue, green, yellow, and orange light are mainly based on the InGaN system, and are achieved by gradually controlling the content of indium (In) (the In component gradually increases as the emission wavelength moves towards longer wavelengths), combined with controlling trace or no aluminum (Al) component and synergistically adjusting the gallium (Ga) component; red light can be controlled by high indium (In) component in the InGaN system, or by controlling the component ratio of aluminum (Al), gallium (Ga), and indium (In) in the AlGaInP system, ultimately achieving precise matching of emission colors in different wavelength bands. The first semiconductor layer 121 in the aforementioned semiconductor epitaxial stack 120 can be implemented using a compound semiconductor such as a III-V or II-VI group semiconductor, and can be doped with a first dopant. The first semiconductor layer 121 can be, for example, one or more materials selected from AlGaN, AlN, InAlGaN, InGaN, AlGaInP, AlInP, 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.

[0056] An active layer 122 is disposed between a first semiconductor layer 121 and a 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. The active layer 122 may have a structure selected from, but is not limited to, a single-well structure, a multi-well structure, a single quantum well structure, a multi-quantum-well (MQW) structure, a quantum dot structure, or a quantum wire structure.

[0057] The active layer 122 may include multiple well layers and barrier layers. For different material systems, the well layers and barrier layers have different material configurations. For example, for an InAlGaN material system that radiates ultraviolet light, both the well layer and the barrier layer are InAlGaN materials, with different Al compositions. The Al composition of the barrier layer is significantly higher than that of the well layer to increase the barrier height, effectively limiting carrier recombination within the well layer and preventing carrier escape. For an InGaN material system that radiates blue, green, yellow, orange, or red light, the well layer is an InGaN material of the corresponding wavelength band, and the barrier layer is a low-In or In-free GaN-based material (containing trace amounts of Al or no Al). For an AlGaInP material system that radiates high brightness, both the well layer and the barrier layer are AlGaInP materials, with the Al composition of the barrier layer significantly higher than that of the well layer, forming a high barrier to confine carriers and meet the light-emitting requirements of high-brightness red LEDs. 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 semiconductor. The second semiconductor layer 123 can be doped with a second dopant. The second semiconductor layer 123 can be, for example, one or more materials such as AlInN, AlGaN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP, and AlInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, or Ba, the second semiconductor layer 123 doped with the second dopant is a p-type semiconductor layer.

[0058] Although not illustrated, it is understood that an electron-blocking layer (EBL) may be disposed between the active layer 122 and the second semiconductor layer 123. The electron-blocking layer, acting as a confinement layer for the active layer 122, can reduce electron leakage.

[0059] Reference Figure 2 The semiconductor epitaxial stack 120 has a first mesa 1201 and a second mesa 1202. For example, the first mesa 1201 can be formed by etching away part of the active layer 122 and the second semiconductor layer 123 to expose the first semiconductor layer 121. The unetched portion of the semiconductor epitaxial stack 120 forms the second mesa 1202, which is the light-emitting region of the light-emitting diode 100. (See also...) Figure 1 The first mesa 1201 and the second mesa 1202 are arranged side by side. In an optional example, the first mesa 1201 may be an open mesa formed on one side or a corner of the light-emitting diode 100. In this embodiment, as... Figure 2As shown, the sidewalls of the light-emitting diode 100 are formed as inclined sidewalls 125. Specifically, the sidewalls of both the first mesa 1201 and the second mesa 1202 are formed as inclined sidewalls. The inclination angles of the two can be the same or different. In this embodiment, the inclined sidewalls 125 of the light-emitting diode 100 mentioned in the following description are broadly understood as the structure formed by the outermost structural layer above the front side 111 of the substrate 110 of the light-emitting diode 100, that is, the sidewalls formed by the second insulating protective layer 142 located on the outermost layer of the light-emitting diode 100. Figure 3 As shown, the angle between the inclined sidewall 125 of the light-emitting diode 100 and the surface of the front side 111 of the substrate 110 is between 30° and 70°, and further between 40° and 60° and 45° and 65°. The inclined design of the sidewall of the light-emitting diode 100 can increase the reflection of light by the sidewall, and also increase its light emission effect.

[0060] like Figure 3 and Figure 4 As shown, the inclined sidewall 125 includes a first segment 1251 connected to the front side 111 of the substrate 110 and a second segment 1252 connected to the first segment 1251, wherein the first segment 1251 includes a protrusion bulging outward from the inclined sidewall 125. As described above regarding the substrate 110, a protrusion structure 113 is formed on the front side 111 of the substrate 110. When etching and dividing the semiconductor epitaxial stack 120 to form an independent light-emitting diode 100, the etching method and etching parameters can be adjusted so that the etching rate of the semiconductor epitaxial stack 120 is faster than the etching rate of the substrate 110. This results in the protrusion structure 113 of the substrate 110 being exposed from the sidewall of the semiconductor epitaxial stack 120 after etching, so that after the subsequent deposition of the material layer, the sidewall of the light-emitting diode 100 forms a protrusion. For example, in an optional example, dry etching is used to etch the semiconductor epitaxial stack 120. During the etching process, parameters such as the type of etching gas, flow rate, etching time, and etching power are adjusted or controlled so that the protrusion structure 113 of the substrate 110 is exposed from the sidewall of the semiconductor epitaxial stack 120.

[0061] In a specific example, the protrusion on the sidewall of the light-emitting diode 100 is formed as a multi-segment structure, specifically, as shown in... Figure 3 As shown, the protrusion includes a first protrusion 12511 connecting the second segment 1252 and a second protrusion 12512 connecting the substrate 110. In a further example, the first segment 1251 also includes a connecting portion 12513 connecting the first protrusion 12511 and the second protrusion 12512, and the connecting portion 12513 can be formed as follows: Figure 3The platform structure shown is a similar platform structure. As described above, by controlling the parameters during the etching process, the first portion 1131 and the second portion 1132 of the protrusion structure 113 above the substrate 110 are exposed. The platform structure or similar platform structure is formed by the different etching rates of the first portion 1131 and the second portion 1132 during the etching process. The material layer above the second portion 1132 or a portion of the second portion 1132 forms the first protrusion 12511 of the protrusion structure, and the material layer above the first portion 1131 or a portion of the first portion 1131 forms the second protrusion 12512 of the protrusion structure. The material layer on the platform structure or similar platform structure forms a connecting portion 12513 of the platform structure or similar platform structure between the first protrusion 12511 and the second protrusion 12512.

[0062] In this example, the inclined sidewall 125 of the light-emitting diode 100 also forms a multi-segment structure. The inclination degree of each segment can be the same or different, that is, the angle between each segment and the plane containing the front surface 111 of the substrate 110 can be the same or different. For example Figure 3 As shown, the angle between the first protrusion 12511 of the first segment 1251 of the inclined sidewall 125 and the plane containing the front surface 111 of the substrate 110 is α1; the angle between the second protrusion 12512 and the plane containing the front surface 111 of the substrate 110 is α2; and the angle between the second segment 1252 of the inclined sidewall 125 and the plane containing the front surface 111 of the substrate 110 is α3. Wherein, 30°≤α1≤70°, further, 40°≤α1≤60°, 45°≤α1≤65°; 30°≤α2≤70°, further, 35°≤α2≤60°, 45°≤α2≤70°; 30°≤α3≤70°, further, 40°≤α3≤65°, 35°≤α3≤65°. Furthermore, the values ​​of α1, α2, and α3 can be the same or different. Preferably, as described above, when etching the first portion 1131 and the second portion 1132 of the protrusion structure 113 above the semiconductor epitaxial stack 120 and the substrate 110, the etching rates of each material layer are different, and the angles between each etched portion and the surface of the substrate 110 will be different. Therefore, when forming the inclined sidewall 125 of the light-emitting diode 100 above each etched portion, the values ​​of α1, α2, and α3 are also different.

[0063] As described above, the first segment 1251 and the second segment 1252 make the inclined sidewall 125 of the light-emitting diode 100 a multi-segment reflective surface. Compared with a smooth sidewall with a uniform inclination, this significantly increases the number of contact interfaces between light and the inclined sidewall 125, i.e., significantly increases the contact area between light and the sidewall. At the same time, the protrusions in the first segment 1251 can provide more reflection paths for light with different propagation directions, avoiding light loss caused by a single reflection angle. This allows oblique rays and scattered rays that are originally easily absorbed to be guided to the light-emitting surface of the chip after multiple reflections, significantly improving the sidewall light extraction rate.

[0064] Similarly combined Figure 3 The inclined sidewall 125 of the light-emitting diode 100 is formed with multiple layers of material and has a certain thickness. Therefore, on the outermost sidewall 125 (i.e., Figure 2 The outer side of the second insulating protective layer 142), the highest point of the protrusion (the highest point of the first protrusion 12511 in this example), and the extension line of the second segment 1252 of the inclined sidewall 125 have a first vertical distance D1, which satisfies: 50 nm ≤ D1 ≤ 1000 nm, and further satisfies: 50 nm ≤ D1 ≤ 800 nm, 150 nm ≤ D1 ≤ 800 nm, 100 nm ≤ D1 ≤ 500 nm, 50 nm ≤ D1 ≤ 500 nm, 200 nm ≤ D1 ≤ 500 nm, etc. Similarly, as... Figure 3 As shown, the junction of the first segment 1251 and the second segment 1252 of the inclined sidewall 125 has a second vertical distance D2 between it and the front surface of the substrate 110. The second vertical distance D2 satisfies: 1 μm ≤ D2 ≤ 5 μm, and further, 1.5 μm ≤ D2 ≤ 4 μm, 2 μm ≤ D2 ≤ 3 μm.

[0065] The aforementioned vertical distance between the protrusion and the inclined sidewall 125 of the LED 100 ensures that the protrusion is neither too high nor too low. If it is too high, the manufacturing process of the LED may become overly complex, while if it is too low, it may fail to increase the light reflection effect. Therefore, the aforementioned arrangement of the protrusion can increase the light reflection of the LED without affecting its manufacturing process, thereby improving the light emission effect of the LED.

[0066] Refer again Figure 1 and Figure 2The light-emitting diode 100 in this embodiment also includes a first insulating protective layer 141, a second insulating protective layer 142, an insulating reflective layer 151, a metal reflective layer 152, and an electrode structure. The insulating reflective layer 151, the first insulating protective layer 141, and the second insulating protective layer 142 are all located on the surface of the semiconductor epitaxial stack 120 and at the inclined sidewall 125. Specifically, they cover the surface and sidewall of the first mesa 1201 and the second mesa 1202 of the semiconductor epitaxial stack 120, and can further extend to cover the surface of the exposed substrate 110.

[0067] In an optional example, the aforementioned insulating reflective layer 151 may be a Bragg reflective layer comprising alternating layers of high-refractive-index material and low-refractive-index material. Here, "high-refractive-index" and "low-refractive-index" refer to the relative refractive indices of the stacked material layers, and do not represent specific refractive index values. The aforementioned high-refractive-index material layer and low-refractive-index material layer may be SiO2, SiN, or SiO2. x N y TiO x A dash breech-guided mirror (DBR) formed by repeatedly stacking two or more of the following materials: Si3N4, Al2O3, TiN, AlN, ZrO2, TiAlN, TiSiN, HfO2, TaO2, NbO2, or MgF2. For example, in this embodiment, the high refractive index material layer is TiO2. x Layers (e.g., TiO2, Ti2O3, or Ti3O5) or NbO y The high-refractive-index material layer (e.g., NbO2 or Nb3O5) is a SiO2 layer, and the low-refractive-index material layer is a SiO2 layer. The total number of stacked layers of the high-refractive-index and low-refractive-index material layers is between 2 and 100 layers, further between 2 and 10 layers, and even further between 2 and 5 layers. The thickness of the high-refractive-index and low-refractive-index material layers is between 100 Å and 6000 Å, and even further between 200 Å and 800 Å, 500 Å and 1000 Å, and 500 Å and 800 Å. The thicknesses of the high-refractive-index and low-refractive-index material layers are usually different.

[0068] A metal reflective layer 152 is located above the insulating reflective layer 151 above the second mesa 1202. This metal reflective layer 152 is preferably a layer of a metal material with high reflectivity, such as one or a combination of Au, Ag, Al, Cu, Cr, etc. In this embodiment, an Ag layer is preferred. The metal reflective layer 152 is electrically connected to the second semiconductor layer 123 at the second mesa 1202. Specifically, as... Figure 2As shown, an insulating reflective layer 151 has a first through-hole 1511 formed above the second mesa 1202, and a metal reflective layer 152 fills the first through-hole 1511 and is electrically connected to the second semiconductor layer 123. The insulating reflective layer 151 and the metal reflective layer 152 work together to form a total internal reflection system, which reflects as much light as possible and makes it exit from the light-emitting side.

[0069] The first insulating protective layer 141 covers the surface and sidewalls of the insulating reflective layer 151 and the metal reflective layer 152. The first insulating protective layer 141 and the second insulating protective layer 142 can be insulating oxides, insulating nitrides, etc., and can have the same or different material compositions. For example, they can be one or more of SiO2, Si3N4, Al2O3, TiO2, ZnO, HfO2, etc. Both the first insulating protective layer 141 and the second insulating protective layer 142 can be a single structure or a multilayer structure. Their thickness is between 100 Å and 30000 Å, and more specifically, between 500 Å and 20000 Å. The second insulating protective layer 142 is located above the first insulating protective layer 141. The first insulating protective layer 141 and the insulating reflective layer 151 enclose the metal reflective layer 152. The first insulating protective layer 141 and the second insulating protective layer 142 can block impurities such as water vapor and electrolyte ions, helping to protect the metal reflective layer 152 from damage, while also improving the brightness of the light-emitting diode and mitigating light decay of the device. The insulating reflective layer 151 is a stack of insulating materials. While increasing the reflection of light, it can work together with the first insulating protective layer 141 and the second insulating protective layer 142 to provide insulation protection, thereby further improving the reliability of the light-emitting diode 100.

[0070] Similarly, Figure 2As shown, the electrode structure includes a first electrode 161 and a second electrode 162. The first electrode 161 is electrically connected to the first semiconductor layer 121, and the second electrode 162 is electrically connected to the second semiconductor layer 123. The first electrode 161 includes a first connecting electrode 1611 and a first pad electrode 1612; the second electrode 162 includes a second connecting electrode 1621 and a second pad electrode 1622. The first connecting electrode 1611 and the second connecting electrode 1621 are located above the first insulating protective layer 141. The first connecting electrode 1611 is electrically connected to the first semiconductor layer 121 via a second through-hole 1411 penetrating the first insulating protective layer 141 and the insulating reflective layer 151 above the first mesa 1201. The second connecting electrode 1621 is connected to the metal reflective layer 152 via a third through-hole 1412 penetrating the first insulating protective layer 141 above the second mesa 1202. Optionally, the first connecting electrode 1611 extends from above the first mesa 1201 along the sidewall between the first mesa 1201 and the second mesa 1202 to above the second mesa 1202, and is insulated from the second connecting electrode 1621 at a distance. Optionally, as Figure 1 and Figure 2 As shown, above the second platform 1202, the first through hole 1511 and the third through hole 1412 are staggered, that is, in Figure 1 In the top view shown, the projected outlines of the first through-hole 1511 and the second through-hole 1411 are spaced apart, do not overlap, and do not intersect. The second connecting electrode 1621 is electrically connected to the second semiconductor layer 123 via the metal reflective layer 152. This arrangement ensures that the metal reflective layer 152 fully covers the surface of the second platform 1202, improving its reflective effect, especially at the first through-hole 1511 of the insulating reflective layer 151. Furthermore, it fully utilizes the conductive properties to achieve the electrical connection between the second connecting electrode 1621 and the second semiconductor layer 123.

[0071] The second insulating protective layer 142 covers the exposed surface and sidewalls of the first insulating protective layer 141, and covers the edge portions of the first connecting electrode 1611 and the second connecting electrode 1621 to electrically isolate the first connecting electrode 1611 and the second connecting electrode 1621. The first pad electrode 1612 and the second pad electrode 1622 are respectively formed above the exposed first connecting electrode 1611 and the second connecting electrode 1621, and are spaced apart from each other.

[0072] The materials of the first connecting electrode 1611 and the second connecting electrode 1621 can be selected from one or more of Cr, Pt, Au, Ni, Ti, and Al. To simplify the manufacturing process, they can have the same material composition so that they can be formed in the same process. Preferably, the underlying metal of the first connecting electrode 1611 and the second connecting electrode 1621 is a Ti metal layer or a Cr metal layer to form a stable adhesion relationship with the first insulating protective layer 141.

[0073] In the optional examples, refer to Figure 2 The light-emitting diode 100 further includes a current-blocking layer 124 and a transparent conductive layer 130. The current-blocking layer 124 is disposed between the second semiconductor layer 123 and the transparent conductive layer 130, and serves to block current. The transparent conductive layer 130 covers the current-blocking layer 124 and covers the exposed surface of the second semiconductor layer 123 at the second mesa 1202, and serves to extend current flow, further improving the electrical characteristics of the light-emitting diode 100. The thickness of the current-blocking layer 124 is between 100 and 400 μm, and the material of the current-blocking layer 124 can be silicon oxide or silicon nitride. The transparent conductive layer 130 is formed above the second mesa 1202. Specifically, it can completely cover the exposed second semiconductor layer 123 of the second mesa 1202, or it can partially cover the second semiconductor layer 123. The transparent conductive layer 130 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, but the embodiments disclosed herein are not limited thereto.

[0074] Example 2

[0075] This embodiment also provides a light-emitting diode, such as... Figure 5 and Figure 6 As shown, the light-emitting diode 100 also includes at least a substrate 110 and a semiconductor epitaxial stack 120 formed on the substrate. The semiconductor epitaxial stack 120 includes a first semiconductor layer 121, an active layer 122, and a second semiconductor layer 123 stacked sequentially. Referring also to… Figure 5 The substrate 110 has a front side 111 and a back side 112, and the semiconductor epitaxial stack 120 is located on the front side 111 of the substrate 110.

[0076] The similarities to the other embodiments will not be repeated here. The difference is that in this embodiment, by controlling the etching parameters during the dry etching process, the first portion 1131 of the protrusion structure 113 of the substrate 110 is etched until only the second portion 1132 is exposed outside the sidewall of the semiconductor epitaxial stack 120. Thus, the first segment 1251 of the inclined sidewall 125 of the light-emitting diode 100, that is, the protrusion of the light-emitting diode 100, only includes the second protrusion 12512.

[0077] At this point, the angle α2 between the second protrusion 12512 and the plane containing the front surface 111 of the substrate 110, and the angle α3 between the second segment 1252 of the inclined sidewall 125 and the plane containing the front surface 111 of the substrate 110, also satisfy the following: 30°≤α2≤70°, further, 35°≤α2≤60°, 45°≤α2≤70°; 30°≤α3≤70°, further, 40°≤α3≤65°, 35°≤α3≤65°. Furthermore, the values ​​of α2 and α3 can be the same or different. Preferably, as described above, when etching the first portion 1131 and the second portion 1132 of the protrusion structure 113 above the semiconductor epitaxial stack 120 and the substrate 110, the etching rates of each material layer are different, and the angle between each etched portion and the surface of the substrate 110 will be different. Therefore, when forming the inclined sidewall 125 of the light-emitting diode 100 above each etched portion, the values ​​of α2 and α3 are also different, and further, α2 < α3.

[0078] Example 3

[0079] This embodiment also provides a light-emitting diode, such as... Figure 7 and Figure 8 As shown, the light-emitting diode 100 also includes at least a substrate 110 and a semiconductor epitaxial stack 120 formed on the substrate. The semiconductor epitaxial stack 120 includes a first semiconductor layer 121, an active layer 122, and a second semiconductor layer 123 stacked sequentially. Referring also to… Figure 5 The substrate 110 has a front side 111 and a back side 112, and the semiconductor epitaxial stack 120 is located on the front side 111 of the substrate 110.

[0080] The similarities to other embodiments will not be repeated here. The difference lies in that, in this embodiment, the protrusion structure 113 above the front side 111 of the substrate 110 is an integral structure with the same forming material, and the protrusion structure 113 and the substrate 110 have the same forming material. At this time, by controlling the etching parameters in the dry etching process, the protrusion structure 113 of the substrate 110 is exposed outside the sidewalls of the semiconductor epitaxial stack 120. Specifically, as... Figure 7 and Figure 8As shown, the protrusion structure 113 above the substrate 110 is formed as a cone-like structure with a highest point (or the protrusion structure 113 is formed as a frustum-like structure with a platform structure at the highest point).

[0081] By controlling the etching parameters during the dry etching process, the etched semiconductor epitaxial stack 120 can be made to cover the highest point (see reference). Figure 2 or Figure 6 (as shown), or to expose the highest point of the etched semiconductor epitaxial stack 120, forming as shown Figure 7 and Figure 8 The structure is shown. When the semiconductor epitaxial stack 120 covers the highest point, the relevant features of the protrusion structure, such as the angle between the protrusion structure and the plane containing the front surface 111 of the substrate 110, the first vertical distance D1 between the highest point of the protrusion structure 113 and the extension line of the second segment 1252, the second vertical distance D2 between the intersection of the first segment 1251 and the second segment 1252 and the plane containing the front surface 111 of the substrate 110, can all be referenced. Figure 3 As shown, the angle between the protrusion structure and the plane where the front surface 111 of the substrate 110 is located is the angle α2 between the second protrusion 12512 and the plane where the front surface 111 of the substrate 110 is located.

[0082] like Figure 7 and Figure 8As shown, when the etched semiconductor epitaxial stack 120 exposes the highest point, the first protrusion 12511 and the second protrusion 12512 of the first segment 1251 of the sidewall 125 of the finally formed light-emitting diode 100 have different extension and protrusion directions relative to the highest point. The highest point is the connection portion 12513 between the first protrusion 12511 and the second protrusion 12512. The angles α1 between the first protrusion 12511 and the plane containing the front surface 111 of the substrate 110, α2 between the second protrusion 12512 and the plane containing the front surface 111 of the substrate 110, and α3 between the second segment 1252 of the inclined sidewall 125 and the plane containing the front surface 111 of the substrate 110 also satisfy the following conditions: 30°≤α1≤70°, further, 40°≤α1≤60°, 45°≤α1≤65°; 30°≤α2≤70°, further, 35°≤α2≤60°, 45°≤α2≤70°; 30°≤α3≤70°, further, 40°≤α3≤65°, 35°≤α3≤65°. Furthermore, the values ​​of α1, α2, and α3 can be the same or different. Preferably, as described above, since the protrusion structure 113 is an integral structure with the same forming material, it has a consistent etching rate. The first part 1131 and the second part 1132 of the etched protrusion structure 113 have the same angle with the surface of the substrate 110. Therefore, when the inclined sidewall 125 of the light-emitting diode 100 is formed above each part of the etched protrusion structure 113, the values ​​of α1 and α2 can be the same.

[0083] The aforementioned protrusions (first protrusion 12511 and second protrusion 12512) give the inclined sidewall 125 a richer structural feature, further increasing the contact area between light and the inclined sidewall 125. Simultaneously, the protrusions in the first segment 1251 provide more reflection paths for light rays from different propagation directions, avoiding light loss caused by a single reflection angle. This allows obliquely incident and scattered light rays, which are easily absorbed, to be guided to the chip's light-emitting surface after multiple reflections, significantly improving the sidewall light extraction rate.

[0084] Example 4

[0085] This embodiment provides a light-emitting device, such as... Figure 9 As shown, the light-emitting device 300 includes a circuit board 301 and at least one light-emitting unit 302 fixed to the circuit board 301. The light-emitting unit 302 includes any one or more light-emitting diodes provided in Embodiments 1 to 3 of this application. Because the light-emitting device includes any one or more light-emitting diodes provided in Embodiments 1 to 3, it has better reliability and good light extraction efficiency.

[0086] 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, comprising at least a substrate and a semiconductor epitaxial stack, wherein the substrate has a front side and a back side disposed opposite to each other; the semiconductor epitaxial stack is located on the front side; characterized in that, The sidewall of the light-emitting diode is an inclined sidewall, which includes a first segment and a second segment. The first segment is located below the second segment and close to the substrate, wherein the first segment includes an outwardly bulging protrusion.

2. The light emitting diode of claim 1, wherein, The angle between the inclined sidewall and the front surface is between 30° and 70°.

3. The light emitting diode of claim 1, wherein, The highest point of the protrusion and the extension line of the second segment of the inclined sidewall have a first vertical distance D1, which satisfies: 0.05 μm ≤ D1 ≤ 1 μm.

4. The light emitting diode of claim 1, wherein, The protrusion includes a first protrusion connecting the second segment and a second protrusion connecting the substrate. The first segment also includes a connecting portion connecting the first protrusion and the second protrusion.

5. The light emitting diode of claim 4, wherein, The angle between the first protrusion and the surface where the front is located is α1, the angle between the second protrusion and the surface where the front is located is α2, and the angle between the second segment and the surface where the front is located is α3. 30°≤α1≤70°, 30°≤α2≤70°, 30°≤α2≤70°, and the values ​​of α1, α2 and α3 are the same or partially different.

6. The light emitting diode of claim 1, wherein, The substrate is a patterned substrate, and a periodically arranged protrusion structure is formed on one side of the front side. The first segment of the inclined sidewall includes at least a portion of the sidewall of the protrusion structure.

7. The light emitting diode of claim 6, wherein, The protrusion structure includes a first portion having the same forming material as the substrate, and a second portion located above the first portion and having a different forming material from the substrate.

8. The light emitting diode of claim 7, wherein, The protrusion is located in the area corresponding to the first part and the second part.

9. The light emitting diode of claim 7, wherein, The protrusion is located in the area corresponding to the first part.

10. The light emitting diode of claim 6, wherein, The protrusion structure has the same forming material as the substrate.

11. The light emitting diode of claim 1, wherein, At the outermost edge of the inclined sidewall, there is a second vertical distance D2 between the junction of the first segment and the second segment and the front surface of the substrate, which satisfies: 1 μm ≤ D2 ≤ 5 μm.

12. The light emitting diode of claim 1, wherein, The 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 disposed around the second mesa and is lower than the second mesa, and the inclined sidewall is the sidewall between the first mesa and the substrate.

13. The light emitting diode of claim 12, wherein, The sidewalls of the second platform are inclined sidewalls.

14. The light-emitting diode according to claim 13, characterized in that, Also includes: An insulating reflective layer is located on the surface of the semiconductor epitaxial stack and at the inclined sidewalls; A metal reflective layer is located above the insulating reflective layer at the second platform, and the metal reflective layer is electrically connected to the second semiconductor layer through a through-hole penetrating the insulating reflective layer; A first insulating protective layer covers the metal reflective layer and the exposed insulating reflective layer.

15. The light-emitting diode according to claim 14, characterized in that, Also includes: The second insulating protective layer is located above the first insulating protective layer; The electrode structure includes a first electrode electrically connected to the first semiconductor layer and a second electrode electrically connected to the second semiconductor layer.

16. 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 15.

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