Light-emitting diodes with improved reliability and their fabrication methods

Abstract

This disclosure provides a light-emitting diode (LED) with improved reliability and its fabrication method, belonging to the field of optoelectronic manufacturing technology. The LED includes a substrate, an epitaxial layer, a current-blocking layer, a transparent conductive layer, and a first electrode. The epitaxial layer and the current-blocking layer are sequentially stacked on the substrate's bearing surface. The surface of the current-blocking layer away from the substrate has a groove. The transparent conductive layer is located on the surface of the epitaxial layer away from the substrate, the surface of the current-blocking layer, and within the groove. The first electrode is located on the transparent conductive layer and at least partially within the groove. This disclosure can increase the contact area between the electrode and the transparent conductive layer, improving the connection reliability between the electrode and the transparent conductive layer.

Description

Technical Field

[0001] This disclosure relates to the field of optoelectronic manufacturing technology, and in particular to a light-emitting diode with improved reliability and a method for its fabrication. Background Technology

[0002] Light-emitting diodes (LEDs) are highly influential new products in the optoelectronics industry. They are characterized by their small size, long lifespan, rich and colorful colors, and low energy consumption. They are widely used in lighting, displays, signal lights, backlights, toys, and other fields.

[0003] In related technologies, light-emitting diodes typically include a substrate, an epitaxial layer, a current blocking layer, a transparent conductive layer, and an electrode. The substrate, epitaxial layer, and current blocking layer are stacked sequentially. The transparent conductive layer is located on the surface of the current blocking layer and the epitaxial layer, and the electrode is located on the transparent conductive layer and above the current blocking layer.

[0004] However, the small contact area between the electrode and the transparent conductive layer makes the electrode prone to detachment, reducing the reliability of the connection between the electrode and the transparent conductive layer. Summary of the Invention

[0005] This disclosure provides a light-emitting diode with improved reliability and a method for fabricating the same, which can increase the contact area between the electrode and the transparent conductive layer, thereby improving the connection reliability between the electrode and the transparent conductive layer. The technical solution is as follows:

[0006] This disclosure provides a light-emitting diode (LED) comprising a substrate, an epitaxial layer, a current blocking layer, a transparent conductive layer, and a first electrode. The epitaxial layer and the current blocking layer are sequentially stacked on the substrate's bearing surface. The surface of the current blocking layer away from the substrate has a groove. The transparent conductive layer is located on the surface of the epitaxial layer away from the substrate, on the surface of the current blocking layer, and within the groove. The first electrode is located on the transparent conductive layer and is at least partially located within the groove.

[0007] In one implementation of this disclosure, the depth of the groove is less than the thickness of the current blocking layer.

[0008] In another implementation of the present disclosure, the depth of the groove is not less than 1 μm, and the distance between the bottom surface of the groove and the surface of the epitaxial layer away from the substrate is not less than 1 μm.

[0009] In another implementation of the present disclosure, the cross-sectional shape of the groove in the direction perpendicular to the substrate is rectangular, trapezoidal, or triangular.

[0010] In another implementation of the present disclosure, the current blocking layer is strip-shaped, the groove is strip-shaped, and the groove extends along the extension direction of the current blocking layer.

[0011] In another implementation of the present disclosure, the current blocking layer is strip-shaped and has a plurality of grooves, which are spaced apart along the extension direction of the current blocking layer.

[0012] In another implementation of the present disclosure, the first electrode includes an electrode block and a finger, one end of the finger is connected to the electrode block, the electrode block is located on the surface of the epitaxial layer, the finger is located on the transparent conductive layer, and at least partially located in the groove; there are multiple current blocking layers, the first electrode includes multiple fingers, the multiple fingers are arranged in a one-to-one correspondence with the multiple current blocking layers, one end of each of the multiple fingers is connected to the electrode block, and the multiple fingers are spaced apart.

[0013] In another implementation of the present disclosure, the first electrode has a reflective surface, which is the surface of the first electrode close to the substrate.

[0014] This disclosure provides a method for fabricating a light-emitting diode (LED). The method includes: providing a substrate; forming an epitaxial layer on the substrate; forming a current blocking layer on the epitaxial layer, wherein the surface of the current blocking layer away from the substrate has a groove; forming a transparent conductive layer on the surface of the current blocking layer, wherein the transparent conductive layer is located on the surface of the epitaxial layer away from the substrate, the surface of the current blocking layer, and within the groove; and fabricating a first electrode, wherein the first electrode is located on the transparent conductive layer and at least partially located within the groove.

[0015] In another implementation of the present disclosure, forming a current blocking layer on the epitaxial layer includes: forming a silicon dioxide layer on the surface of the epitaxial layer, etching the silicon dioxide layer, and forming the groove on the surface of the silicon dioxide layer away from the substrate, wherein the depth of the groove is less than the thickness of the current blocking layer.

[0016] The beneficial effects of the technical solutions provided in this disclosure include at least the following:

[0017] The light-emitting diode provided in this embodiment has a groove formed on the surface of the current blocking layer away from the substrate, and the transparent conductive layer is also located within the groove. Compared to a planar current blocking layer, the current blocking layer with the groove increases the effective coverage area of ​​the transparent conductive layer on the current blocking layer. Since at least a portion of the first electrode is located in the region of the transparent conductive layer located within the groove, the contact area between the first electrode and the transparent conductive layer is larger, reducing the risk of the first electrode detaching and thus allowing for a more stable connection between the first electrode and the transparent conductive layer. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a top view of a light-emitting diode provided in an embodiment of this disclosure;

[0020] Figure 2 This is a cross-sectional view of a light-emitting diode according to an embodiment of this disclosure;

[0021] Figure 3 This is a flowchart of a method for fabricating a light-emitting diode provided in an embodiment of this disclosure.

[0022] The markings in the diagram are explained as follows:

[0023] 10. Substrate;

[0024] 20. Epitaxial layer; 21. First semiconductor layer; 22. Light-emitting layer; 23. Second semiconductor layer; 24. Recessed structure;

[0025] 30. Current blocking layer; 31. Groove;

[0026] 40. Transparent conductive layer;

[0027] 51. First electrode; 511. Electrode block; 512. Finger;

[0028] 52. Second electrode;

[0029] 60. Passivation layer; 61. Via. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0031] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” “third,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the elements or objects preceding “comprising” or “including” encompass the elements or objects listed following “comprising” or “including” and their equivalents, and do not exclude other elements or objects. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” “right,” “top,” and “bottom,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0032] Figure 1 This is a top view of a light-emitting diode provided in an embodiment of this disclosure. Figure 1 As shown, the light-emitting diode includes a substrate 10, an epitaxial layer 20, a current blocking layer 30, a transparent conductive layer 40, and a first electrode 51.

[0033] Figure 2 This is a cross-sectional view of a light-emitting diode according to an embodiment of this disclosure. Figure 2 yes Figure 1 A cross-sectional view showing section line AA. (See diagram below.) Figure 2 As shown, the epitaxial layer 20 and the current blocking layer 30 are sequentially stacked on the bearing surface of the substrate 10;

[0034] like Figure 2 As shown, the surface of the current blocking layer 30 away from the substrate 10 has a groove 31, and the transparent conductive layer 40 is located on the surface of the epitaxial layer 20 away from the substrate 10, the surface of the current blocking layer 30, and in the groove 31.

[0035] The first electrode is located on the transparent conductive layer and is at least partially located within the groove.

[0036] For example, such as Figure 1 As shown, the first electrode 51 includes an electrode block 511 and a finger 512. One end of the finger 512 is connected to the electrode block 511. The electrode block 511 is located on the surface of the epitaxial layer, and the finger 512 is located on the transparent conductive layer 40 and is at least partially located in the groove 31.

[0037] The light-emitting diode provided in this embodiment has a groove formed on the surface of the current blocking layer away from the substrate, and the transparent conductive layer is also located within the groove. Compared to a planar current blocking layer, the current blocking layer with the groove increases the effective coverage area of ​​the transparent conductive layer on the current blocking layer. Since the finger of the first electrode is located in the area where the transparent conductive layer is located within the groove, the contact area between the finger and the transparent conductive layer is larger, which reduces the risk of the finger falling off, thereby allowing for a more stable connection between the first electrode and the transparent conductive layer.

[0038] Meanwhile, the contact area between the current blocking layer 30 and the transparent conductive layer 40 after the groove 31 is set is larger, which can reduce the voltage and improve the anti-static discharge capability of the light-emitting diode.

[0039] Furthermore, after the current blocking layer 30 is provided with the groove 31, the vertical distance between the first electrode 51 provided above the groove 31 and the light-emitting layer 22 in the epitaxial layer 20 becomes shorter, which can reduce the distance that photons scatter in the medium. The shorter the path that light travels, the less photons the material absorbs, thereby improving the brightness of the light-emitting diode.

[0040] Optionally, the substrate 10 may be a sapphire substrate 10, a silicon substrate 10, or a silicon carbide substrate 10. The substrate 10 may be a flat substrate 10 or a patterned substrate 10.

[0041] As an example, in this embodiment of the disclosure, the substrate 10 is a sapphire substrate 10. The sapphire substrate 10 is a commonly used substrate 10, with mature technology and low cost. Specifically, it can be a patterned sapphire substrate 10 or a flat sapphire substrate 10.

[0042] Optionally, the epitaxial layer 20 may include a first semiconductor layer 21, a light-emitting layer 22, and a second semiconductor layer 23 stacked sequentially.

[0043] In this process, one of the first semiconductor layer 21 and the second semiconductor layer 23 can be the second semiconductor layer 23, and the other of the first semiconductor layer 21 and the second semiconductor layer 23 can be the first semiconductor layer 21.

[0044] For example, the first semiconductor layer 21 may be an n-type GaN layer.

[0045] For example, the light-emitting layer 22 may include alternately grown InGaN quantum well layers and GaN quantum barrier layers. The light-emitting layer 22 may include 3 to 8 alternating stacked InGaN quantum well layers and GaN quantum barrier layers.

[0046] For example, the second semiconductor layer 23 may be a p-type GaN layer.

[0047] Optionally, the substrate 10 may have multiple protrusions on its bearing surface, forming a surface with multiple protrusions for the light-emitting structure. By providing multiple protrusions on the bearing surface of the substrate 10 for growing the epitaxial layer 20, a patterned substrate 10 is formed, which is beneficial to improving the growth quality of the epitaxial layer 20.

[0048] The bearing surface of the substrate 10 is the side surface on the substrate 10 used for growing the epitaxial layer 20.

[0049] Optionally, the current blocking layer 30 can be a silicon dioxide layer, located on the surface of the second semiconductor layer 23. Silicon dioxide has good insulating properties, preventing current from being directly conducted through the first electrode 51 and the transparent conductive layer 40 to the area directly below the first electrode 51, so that the current can be extended through the transparent conductive layer 40 to all parts of the epitaxial layer 20.

[0050] In this embodiment of the disclosure, the transparent conductive layer 40 is located between the second semiconductor layer 23 and the electrode.

[0051] Optionally, the transparent conductive layer 40 can be an indium tin oxide (ITO) film. Indium tin oxide films have good transmittance and low resistivity. Using an indium tin oxide film as the transparent conductive layer 40 allows more light to pass through, thus ensuring optimal performance. Simultaneously, due to its low resistivity, it also facilitates carrier conduction, improving injection efficiency.

[0052] For example, when the transparent conductive layer 40 is an ITO layer, the thickness of the transparent conductive layer 40 can be from 50 angstroms to 5000 angstroms.

[0053] Optionally, the transparent conductive layer 40 can be a NiAu layer. The NiAu layer has good light transmittance, which not only facilitates carrier conduction but also effectively prevents the light from being blocked from the epitaxial layer 20.

[0054] For example, when the transparent conductive layer 40 is a NiAu layer, the thickness of the transparent conductive layer 40 may not exceed 20 angstroms.

[0055] Optionally, such as Figure 2 As shown, the depth of the groove 31 is less than the thickness of the current blocking layer 30. That is, there is a gap between the bottom surface of the groove 31 and the surface of the current blocking layer 30 near the substrate 10. By setting the groove depth of the groove 31 to be less than the thickness of the current blocking layer 30, the current blocking layer 30 is always in a continuous state, so as to prevent the current from being directly conducted through the transparent conductive layer 40 to the area directly below the first electrode 51, and to allow the current to extend through the transparent conductive layer 40 to all parts of the epitaxial layer 20.

[0056] Optionally, the groove depth of the groove 31 is not less than 1 μm, and the distance between the bottom surface of the groove 31 and the surface of the epitaxial layer 20 away from the substrate 10 is not less than 1 μm.

[0057] By setting the groove depth of the groove 31 within the above-mentioned range, it is possible to avoid the groove depth of the groove 31 being too small, which would prevent it from effectively increasing the coverage area of ​​the transparent conductive layer 40 on the current blocking layer 30; and it is also possible to avoid the groove depth of the groove 31 being too large, which would prevent it from effectively isolating the first electrode 51 and the epitaxial layer 20.

[0058] For example, the groove depth of the groove 31 can be 1.5 μm.

[0059] Optionally, the cross-sectional shape of the groove 31 in the direction perpendicular to the substrate 10 is rectangular, trapezoidal or triangular.

[0060] For example, the groove 31 has a rectangular cross-sectional shape in the direction perpendicular to the substrate 10. Providing a rectangular groove 31 on the surface of the current blocking layer 30 increases the contact area between the groove 31 and the transparent conductive layer 40, reduces voltage, and improves the electrostatic discharge capability of the light-emitting diode.

[0061] For example, such as Figure 1 As shown, the cross-sectional shape of the groove 31 in the direction perpendicular to the substrate 10 is an inverted trapezoid. The dimension of the end of the groove 31 near the substrate 10 is smaller than the dimension of the end of the groove 31 away from the substrate 10.

[0062] By setting the groove wall of the groove 31 as an inclined slope, the transparent conductive layer 40 extends more smoothly from the surface of the current blocking layer 30 into the groove 31 along the inclined slope, so as to avoid the problem of the transparent conductive layer 40 breaking at the corner.

[0063] Meanwhile, compared to setting the groove wall of the groove 31 to be vertical, setting the groove wall of the groove 31 to be an inclined slope can further increase the contact area between the groove 31 and the transparent conductive layer 40, reduce the voltage, and improve the anti-static discharge capability of the light-emitting diode.

[0064] For example, the groove 31 has a triangular cross-sectional shape in the direction perpendicular to the substrate 10. The size of the end of the groove 31 near the substrate 10 is smaller than the size of the end of the groove 31 away from the substrate 10.

[0065] By setting the groove wall of the groove 31 as an inclined slope, the transparent conductive layer 40 extends more smoothly from the surface of the current blocking layer 30 into the groove 31 along the inclined slope, so as to avoid the problem of the transparent conductive layer 40 breaking at the corner.

[0066] Meanwhile, the triangular groove 31 on the surface of the current blocking layer 30 can increase the contact area between the groove 31 and the transparent conductive layer 40, reduce the voltage, and improve the anti-static discharge capability of the light-emitting diode.

[0067] In this embodiment of the present disclosure, one end of the finger 512 of the first electrode 51 is connected to the electrode block 511, and the finger 512 corresponds one-to-one with the current blocking layer 30. The orthographic projection of the finger 512 on the bearing surface of the substrate 10 is located within the orthographic projection of the corresponding current blocking layer 30 on the bearing surface of the substrate 10.

[0068] By configuring the first electrode 51 as an electrode block 511 connected to the finger 512, the current on the electrode block 511 can be transmitted to various areas of the epitaxial layer 20 through the finger 512, improving the current expansion effect. Furthermore, each finger 512 is provided with a corresponding current blocking layer 30, which prevents the current from being directly conducted through the finger 512 and the transparent conductive layer 40 to the area directly below the finger 512, allowing the current to expand to various parts of the epitaxial layer 20 through the transparent conductive layer 40.

[0069] For example, such as Figure 2 As shown, the finger 512 is strip-shaped, and correspondingly, the current blocking layer 30 is also strip-shaped. The current blocking layer 30 has a plurality of grooves 31, which are spaced apart along the extending direction of the current blocking layer 30.

[0070] By adding more grooves 31, the effective coverage area of ​​the transparent conductive layer 40 on the current blocking layer 30 can be further increased. This also increases the contact area between the first electrode 51 and the transparent conductive layer 40, allowing for a more stable connection and reducing the risk of the first electrode 51 detaching. Simultaneously, the larger contact area between the current blocking layer 30 and the transparent conductive layer 40 reduces voltage and improves the electrostatic discharge capability of the light-emitting diode.

[0071] For example, the current blocking layer 30 is strip-shaped, and the groove 31 is strip-shaped, extending along the extension direction of the current blocking layer 30.

[0072] By setting strip-shaped grooves 31 with a shape matching the current blocking layer 30, and maximizing the groove depth of the current blocking layer 30, the effective coverage area of ​​the transparent conductive layer 40 on the current blocking layer 30 can be maximized. This increases the contact area between the first electrode 51 and the transparent conductive layer 40, effectively reducing the risk of the first electrode 51 detaching. Simultaneously, the larger contact area between the current blocking layer 30 and the transparent conductive layer 40 reduces voltage and improves the electrostatic discharge capability of the light-emitting diode.

[0073] Optionally, there are multiple current blocking layers 30, and the first electrode 51 includes multiple fingers 512. The multiple fingers 512 are arranged in a one-to-one correspondence with the multiple current blocking layers 30. One end of each of the multiple fingers 512 is connected to the electrode block 511, and the multiple fingers 512 are distributed at intervals.

[0074] For example, such as Figure 2 As shown, the first electrode 51 includes two fingers 512, one end of each finger 512 is connected to the electrode block 511, and the two fingers 512 are spaced apart.

[0075] By setting two spaced fingers 512, the current on the electrode block 511 can be transmitted to various regions of the epitaxial layer 20 through the two fingers 512, thereby improving the current expansion effect.

[0076] Optionally, such as Figure 1 , 2 As shown, the light-emitting diode also includes a second electrode 52. The surface of the second semiconductor layer 23 on the epitaxial layer 20 has a recessed structure 24 that exposes the first semiconductor layer 21. The first electrode 51 is located on the surface of the second semiconductor layer 23, and the second electrode 52 is located in the recessed structure 24 and on the surface of the first semiconductor layer 21.

[0077] For example, such as Figure 1 As shown, the light-emitting diode may further include a passivation layer 60, which is located at least on the surface of the second semiconductor layer 23, within the recessed structure 24, and on the surface of the first semiconductor layer 21. The surface of the passivation layer also has vias 61 that expose the first electrode 51 and the second electrode 52, respectively.

[0078] This exposes the two electrodes outside the passivation layer, allowing them to be connected to an external power source and enabling the epitaxial layer 20 to emit light when energized.

[0079] For example, the passivation layer can be a distributed Bragg reflection (DBR layer), which comprises multiple periodically alternating layers of SiO2 and TiO2. The number of periods in the DBR layer can be between 20 and 50. For example, the DBR layer may have 32 periods.

[0080] The thickness of the SiO2 layer in the DBR layer can be from 800 angstroms to 1200 angstroms, and the thickness of the TiO2 layer can be from 500 angstroms to 900 angstroms.

[0081] In addition to its passivation function, the DBR layer also reflects light emitted from the light-emitting layer 22 toward the DBR layer back to the substrate, thereby improving the light emission effect.

[0082] Optionally, the surface of the first electrode 51 near the substrate 10 has a reflective surface, which is the surface of the first electrode 51 near the substrate 10.

[0083] For example, the metal layer on the light-emitting surface of the first electrode 51 can be a metal film layer with good reflective properties. For instance, an Au layer is provided on the side of the first electrode 51 near the substrate 10 to enhance the reflective effect of the surface of the first electrode 51 near the substrate 10.

[0084] Since the first electrode 51 is located on the groove 31, the area of ​​the surface of the first electrode 51 near the substrate 10 is also increased. Since the surface of the first electrode 51 near the substrate 10 is provided with a reflective structure, the area of ​​the side of the first electrode 51 used for reflection is also increased, thereby allowing more light to be reflected in the direction of the substrate 10 and improving the brightness of the light-emitting diode.

[0085] Figure 3 This is a flowchart illustrating a method for fabricating a light-emitting diode (LED) according to an embodiment of this disclosure. Figure 3 As shown, the preparation method includes:

[0086] S11: Provide a substrate.

[0087] S12: An epitaxial layer is formed on the substrate.

[0088] S13: A current blocking layer is formed on the epitaxial layer.

[0089] The surface of the current blocking layer away from the substrate has grooves.

[0090] S14: A transparent conductive layer is formed on the surface of the current blocking layer.

[0091] The transparent conductive layer is located on the surface of the epitaxial layer away from the substrate, on the surface of the current blocking layer, and in the groove.

[0092] S15: Fabricate the first electrode.

[0093] The first electrode is located on the transparent conductive layer and is at least partially located within the groove.

[0094] In this embodiment of the present disclosure, the first electrode includes an electrode block and a finger, one end of the finger is connected to the electrode block, the electrode block is located on the surface of the epitaxial layer, and the finger is located on the transparent conductive layer and is at least partially located in the groove.

[0095] The light-emitting diode fabricated using this method has a groove formed on the surface of the current blocking layer away from the substrate, and the transparent conductive layer is also located within the groove. Compared to a planar current blocking layer, the grooved current blocking layer increases the effective coverage area of ​​the transparent conductive layer on the current blocking layer. Since the finger of the first electrode is located in the area where the transparent conductive layer is located within the groove, the contact area between the finger and the transparent conductive layer is larger, reducing the risk of finger detachment and thus allowing for a more stable connection between the first electrode and the transparent conductive layer.

[0096] In step S11, the substrate can be a sapphire substrate, a silicon substrate, or a silicon carbide substrate. The substrate can be a flat substrate or a patterned substrate.

[0097] As an example, in this embodiment of the disclosure, the substrate is a sapphire substrate. Sapphire substrates are a commonly used substrate, with mature technology and low cost. Specifically, it can be a patterned sapphire substrate or a flat sapphire substrate.

[0098] like Figure 1 As shown, the epitaxial layer formed in step S12 is located on the bearing surface of the substrate. The epitaxial layer may include a first semiconductor layer, a light-emitting layer and a second semiconductor layer stacked sequentially.

[0099] In this configuration, one of the first semiconductor layer and the second semiconductor layer can be the second semiconductor layer, and the other of the first semiconductor layer and the second semiconductor layer can be the first semiconductor layer.

[0100] For example, the first semiconductor layer may be an n-type GaN layer.

[0101] For example, the light-emitting layer may include alternately grown InGaN quantum well layers and GaN quantum barrier layers. The light-emitting layer may include 3 to 8 alternating stacked InGaN quantum well layers and GaN quantum barrier layers.

[0102] For example, the second semiconductor layer may be a p-type GaN layer.

[0103] The process of preparing the epitaxial layer in step S12 may include the following steps:

[0104] The first step is to grow a first semiconductor layer, a light-emitting layer, and a second semiconductor layer sequentially on the substrate bearing surface to form an epitaxial layer.

[0105] The first semiconductor layer can be an n-type GaN layer.

[0106] For example, the thickness of the first semiconductor layer can be from 1 μm to 5 μm, for example, the thickness of the first semiconductor layer is 3 μm.

[0107] For example, the doping concentration of the n-type dopant in the first semiconductor layer can be 10.18 / cm 3 Up to 10 19 / cm 3 For example, a doping concentration of 5 × 10 18 / cm 3 .

[0108] The light-emitting layer may include alternating InGaN quantum well layers and GaN quantum barrier layers. The light-emitting layer may include 3 to 8 alternating stacked InGaN quantum well layers and GaN quantum barrier layers.

[0109] For example, the thickness of the InGaN quantum well can be from 2.5 nm to 3.5 nm, for example, the thickness of the InGaN quantum well is 3 nm; the thickness of the GaN quantum barrier can be from 9 nm to 20 nm, for example, the thickness of the GaN quantum barrier is 15 nm.

[0110] For example, the number of InGaN quantum well layers is the same as the number of GaN quantum barrier layers. The number of InGaN quantum well layers can be from 3 to 8, for example, the number of InGaN quantum well layers is 7.

[0111] The second semiconductor layer can be a p-type GaN layer.

[0112] For example, the thickness of the second semiconductor layer can be from 100 nm to 800 nm, for example, the thickness of the second semiconductor layer is 450 nm.

[0113] For example, the doping concentration of the p-type dopant in the second semiconductor layer can be 10. 18 / cm 3 Up to 10 20 / cm 3 For example, a doping concentration of 10 19 / cm 3 .

[0114] The second step is to etch a recessed structure on the surface of the second semiconductor layer to expose the first semiconductor layer.

[0115] Specifically, this may involve: forming a photoresist pattern on a second semiconductor layer using photolithography; then, dry etching the second semiconductor layer and the light-emitting layer that are not covered by the photoresist to form a recessed structure exposing the first semiconductor layer; and finally, removing the photoresist.

[0116] The depth of the recessed structure can be from 10,000 Å to 16,000 Å.

[0117] Step S13 may include: forming a silicon dioxide layer on the surface of the epitaxial layer, etching the silicon dioxide layer, and forming a groove on the surface of the silicon dioxide layer away from the substrate.

[0118] Specifically, the fabrication of the current blocking layer may include: forming a silicon dioxide layer on the surface of the second semiconductor layer, and transferring the pattern on the photomask onto the silicon dioxide layer through a photolithography process to form the current blocking layer.

[0119] Optionally, such as Figure 1 As shown, the depth of the groove is less than the thickness of the current blocking layer. The bottom surface of the groove is spaced from the surface of the current blocking layer near the substrate.

[0120] Optionally, the groove depth is not less than 1 μm, and the spacing is not less than 1 μm. For example, the groove depth can be 1.5 μm.

[0121] Optionally, the cross-sectional shape of the groove in the direction perpendicular to the substrate is rectangular, trapezoidal, or triangular.

[0122] The preparation of the transparent conductive layer in step S14 may include: first laying an indium tin oxide film, and then using photolithography and etching techniques to pattern the indium tin oxide film to obtain the transparent conductive layer.

[0123] After the first electrode is prepared in step S15, the second electrode may also be prepared within the recessed structure.

[0124] Optionally, both the first electrode and the second electrode comprise one or more of the following metals: gold, aluminum, nickel, platinum, chromium, and titanium.

[0125] After the electrodes are fabricated, passivation layers can also be formed in the second semiconductor layer, within the recessed structure, and on the first semiconductor layer.

[0126] The passivation layer is located at least on the surface of the second semiconductor layer, within the recessed structure, and on the surface of the first semiconductor layer. The surface of the passivation layer also has two vias that expose the two electrodes respectively.

[0127] For example, the passivation layer may be a SiO2 layer.

[0128] The process of forming the passivation layer may include: first laying a SiO2 layer, and then using photolithography and etching techniques to pattern the SiO2 layer to obtain the passivation layer.

[0129] The above is not intended to limit this disclosure in any way. Although this disclosure has been disclosed above through embodiments, it is not intended to limit this disclosure. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this disclosure. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this disclosure without departing from the content of the technical solution of this disclosure shall still fall within the scope of the technical solution of this disclosure.

Claims

1. A light-emitting diode, characterized in that, The light-emitting diode includes a substrate (10), an epitaxial layer (20), a current blocking layer (30), a transparent conductive layer (40), and a first electrode (51). The epitaxial layer (20) includes a first semiconductor layer (21), a light-emitting layer (22), and a second semiconductor layer (23) stacked sequentially. The epitaxial layer (20) and the current blocking layer (30) are stacked sequentially on the bearing surface of the substrate (10). The current blocking layer (30) has a groove (31) on its surface away from the substrate (10). The transparent conductive layer (40) is located on the surface of the epitaxial layer (20) away from the substrate (10), on the surface of the current blocking layer (30), and in the groove (31). The depth of the groove (31) is less than the thickness of the current blocking layer (30). The first electrode (51) is located on the transparent conductive layer (40) and is at least partially located within the groove (31).

2. The light-emitting diode according to claim 1, characterized in that, The depth of the groove (31) is not less than 1 μm, and the distance between the bottom surface of the groove (31) and the surface of the epitaxial layer (20) away from the substrate (10) is not less than 1 μm.

3. The light-emitting diode according to claim 1, characterized in that, The groove (31) has a rectangular, trapezoidal or triangular cross-sectional shape in the direction perpendicular to the substrate (10).

4. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The current blocking layer is strip-shaped, the groove is strip-shaped, and the groove extends along the extension direction of the current blocking layer.

5. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The current blocking layer is strip-shaped, and the current blocking layer (30) has a plurality of grooves (31), which are spaced apart along the extension direction of the current blocking layer (30).

6. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The first electrode (51) includes an electrode block (511) and a finger (512), one end of the finger (512) is connected to the electrode block (511), the electrode block (511) is located on the surface of the epitaxial layer, and the finger (512) is located on the transparent conductive layer (40) and at least partially located in the groove (31). There are multiple current blocking layers (30), and the first electrode (51) includes multiple fingers (512). The multiple fingers (512) are arranged in a one-to-one correspondence with the multiple current blocking layers (30). One end of each of the multiple fingers (512) is connected to the electrode block (511), and the multiple fingers (512) are distributed at intervals.

7. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The first electrode (51) has a reflective surface, which is the surface of the first electrode (51) near the substrate (10).

8. A method for fabricating a light-emitting diode, characterized in that, The preparation method includes: Provide a substrate; An epitaxial layer is formed on the substrate, the epitaxial layer comprising a first semiconductor layer, a light-emitting layer, and a second semiconductor layer stacked sequentially. A current blocking layer is formed on the epitaxial layer, and the surface of the current blocking layer away from the substrate has a groove. A transparent conductive layer is formed on the surface of the current blocking layer. The transparent conductive layer is located on the surface of the epitaxial layer away from the substrate, on the surface of the current blocking layer, and within the groove. The depth of the groove is less than the thickness of the current blocking layer. A first electrode is fabricated, which is located on a transparent conductive layer and is at least partially located within the groove.

9. The preparation method according to claim 8, characterized in that, The formation of a current blocking layer on the epitaxial layer includes: A silicon dioxide layer is formed on the surface of the epitaxial layer, the silicon dioxide layer is etched, and the groove is formed on the surface of the silicon dioxide layer away from the substrate, the depth of the groove being less than the thickness of the current blocking layer.

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