Light-emitting diode and light-emitting diode preparation method

Abstract

The invention provides a light emitting diode and a light emitting diode preparation method. The light emitting diode comprises an epitaxial protection structure, an epitaxial structure, a first electrode and a second electrode, the first electrode and the second electrode are respectively connected with the epitaxial structure; the epitaxial protection structure is of a cup-shaped structure, the epitaxial structure is located in an opening of the epitaxial protection structure, and the epitaxial protection structure wraps the bottom and the side wall of the epitaxial structure.

Description

Technical Field

[0001] This disclosure relates to the field of light-emitting devices, and in particular to a light-emitting diode and a method for fabricating a light-emitting diode. Background Technology

[0002] Light-emitting diodes (LEDs) can cover a wavelength range from ultraviolet to infrared. Currently, the low-resolution display market is still dominated by liquid crystal displays (LCDs), but miniature LEDs are gradually gaining attention in the low-resolution display market due to their inherent advantages.

[0003] In related technologies, the structure of a light-emitting diode during the fabrication process includes a substrate, a bonding layer, an epitaxial structure, a first electrode, and a second electrode. The first electrode and the second electrode are respectively connected to the epitaxial structure, and the epitaxial structure is bonded to the substrate through the bonding layer.

[0004] After the above fabrication of the light-emitting diode is completed, the substrate usually needs to be removed. After the substrate is removed, there is a bonding layer residue on the epitaxial structure, which will affect the brightness and reliability. Summary of the Invention

[0005] This disclosure provides a light-emitting diode (LED) and a method for manufacturing the LED, which can ensure the brightness and reliability of the LED. The technical solution is as follows:

[0006] On one hand, a light-emitting diode is provided, the light-emitting diode comprising: an epitaxial protection structure, an epitaxial structure, a first electrode, and a second electrode;

[0007] The first electrode and the second electrode are respectively connected to the epitaxial structure;

[0008] The epitaxial protective structure is a cup-shaped structure, and the epitaxial structure is located inside the opening of the epitaxial protective structure. The epitaxial protective structure covers the bottom and sidewalls of the epitaxial structure.

[0009] Optionally, the epitaxial protective structure is a film layer attached to the bottom and sidewalls of the epitaxial structure;

[0010] The epitaxial protective structure is a film formed from one of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide; or,

[0011] The epitaxial protective structure is a stack formed from multiple of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide.

[0012] Optionally, the thickness of the epitaxial protective structure is 0.1 to 5 micrometers.

[0013] Optionally, the angle between the bottom surface of the extended protective structure and the sidewall of the extended protective structure is 60 to 120 degrees.

[0014] Optionally, the light-emitting diode further includes: a passivation layer;

[0015] The passivation layer is located within the opening of the epitaxial protection structure and covers the epitaxial structure;

[0016] The surface of the passivation layer is flush with the top of the opening of the epitaxial protection structure.

[0017] On the other hand, a method for fabricating a light-emitting diode is provided, the method comprising:

[0018] An epitaxial film is formed on the first substrate;

[0019] The epitaxial film is bonded to the second substrate, and the first substrate is removed;

[0020] The epitaxial film is patterned to obtain an epitaxial structure;

[0021] An epitaxial protective structure is formed at the bottom and sidewalls of the epitaxial structure. The epitaxial protective structure is a cup-shaped structure. The epitaxial structure is located inside the opening of the epitaxial protective structure and covers the bottom and sidewalls of the epitaxial structure.

[0022] A bonding layer is formed on the third substrate;

[0023] The bottom surface of the epitaxial protection structure is bonded to the bonding layer, and the second substrate is removed. The opening of the epitaxial protection structure faces the side away from the third substrate.

[0024] Optionally, bonding the epitaxial film to the second substrate includes:

[0025] A photosensitive organic bonding layer is spin-coated onto the second substrate;

[0026] The epitaxial film is bonded together with the photosensitive organic bonding layer.

[0027] Optionally, the epitaxial film layer is patterned, including:

[0028] The epitaxial film and the photosensitive organic bonding layer are etched such that the spacing between the photosensitive organic bonding layers under the adjacent epitaxial structures is 2 to 10 micrometers larger than the spacing between the adjacent epitaxial structures.

[0029] Optionally, an epitaxial protective structure is formed at the bottom and sidewalls of the epitaxial structure, comprising:

[0030] A film layer formed of one of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide is deposited on the bottom and sidewalls of the epitaxial structure; or, a stack of multiple of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide is deposited on the bottom and sidewalls of the epitaxial structure.

[0031] Optionally, the method further includes:

[0032] Before the epitaxial film is bonded to the second substrate, a passivation layer is formed on the epitaxial film;

[0033] After the epitaxial protection structure is formed, the passivation layer is located inside the opening of the epitaxial protection structure, and the surface of the passivation layer is flush with the top of the opening of the epitaxial protection structure.

[0034] The beneficial effects of the technical solutions provided in this disclosure are:

[0035] In this embodiment, by placing the epitaxial structure within the opening of the cup-shaped epitaxial protective structure, the bottom of the cup-shaped epitaxial protective structure contacts the bonding layer during fabrication. When the substrate connected by the bonding layer needs to be removed, only the bonding layer and the epitaxial protective structure need to be separated, without affecting the epitaxial structure, thus ensuring the brightness and reliability of the epitaxial structure. Moreover, the aforementioned epitaxial protective structure covers the bottom and sidewalls of the epitaxial structure, further improving the reliability of the epitaxial structure. Attached Figure Description

[0036] 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.

[0037] Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure;

[0038] Figure 2 This is a flowchart of a method for fabricating a light-emitting diode provided in an embodiment of this disclosure;

[0039] Figure 3 This is a flowchart of another method for fabricating a light-emitting diode provided in this disclosure embodiment;

[0040] Figure 4 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode provided in this embodiment of the disclosure;

[0041] Figure 5 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode provided in this embodiment of the disclosure;

[0042] Figure 6 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode provided in this embodiment of the disclosure;

[0043] Figure 7 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode provided in this embodiment of the disclosure;

[0044] Figure 8 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode provided in this embodiment of the disclosure;

[0045] Figure 9 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode provided in this embodiment of the disclosure;

[0046] Figure 10 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode provided in this embodiment of the disclosure;

[0047] Figure 11 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode provided in the embodiments of this disclosure.

[0048] The attached figures are labeled as follows:

[0049] 10: Third substrate; 20: Bonding layer; 30: Epitaxial protective structure; 31: Bottom surface; 32: Opening; 33: Sidewall; 40: Epitaxial structure; 50: Passivation layer; 60: First electrode; 70: Second electrode;

[0050] 401: First semiconductor layer; 402: Active layer; 403: Second semiconductor layer; 501: First via; 502: Second via;

[0051] 111: First substrate; 112: Photosensitive bonding layer; 113: Second substrate; 310: Epitaxial protective material. Detailed Implementation

[0052] 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.

[0053] Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of this disclosure. See also... Figure 1 The light-emitting diode includes: an epitaxial protection structure 30, an epitaxial structure 40, a first electrode 60, and a second electrode 70.

[0054] The first electrode 60 and the second electrode 70 are respectively connected to the epitaxial structure 40. The epitaxial protection structure 30 is a cup-shaped structure, and the epitaxial structure 40 is located within the opening 32 of the epitaxial protection structure 30, covering the bottom and sidewalls of the epitaxial structure 40.

[0055] In this embodiment, by placing the epitaxial structure within the opening of the cup-shaped epitaxial protective structure, the bottom of the cup-shaped epitaxial protective structure contacts the bonding layer during fabrication. When the substrate connected by the bonding layer needs to be removed, only the bonding layer and the epitaxial protective structure need to be separated, without affecting the epitaxial structure, thus ensuring the brightness and reliability of the epitaxial structure. Moreover, the aforementioned epitaxial protective structure covers the bottom and sidewalls of the epitaxial structure, further improving the reliability of the epitaxial structure.

[0056] In this embodiment of the disclosure, the cup-shaped structure refers to the structure formed by the bottom surface 31 and the sidewall 33 of the extended protective structure 30, which has an opening 32, i.e., a groove. The cup-shaped structure can also be called a bowl-shaped structure, a barrel-shaped structure, etc.

[0057] In this embodiment of the present disclosure, the term "the outer protective structure 30 covering the bottom and sidewalls of the outer protective structure 40" means that the bottom surface 31 of the outer protective structure 30 is attached to the bottom of the outer protective structure 40, and the sidewall 33 of the outer protective structure 30 is attached to the sidewalls of the outer protective structure 40, thereby forming a covering.

[0058] In this embodiment of the disclosure, the epitaxial protective structure 30 is a film layer attached to the bottom and sidewalls of the epitaxial structure 40.

[0059] That is, the epitaxial protective structure 30 is a whole film layer attached to the epitaxial structure, and the opening 32 of the epitaxial protective structure 30 is formed by the whole film layer covering the epitaxial structure, rather than by patterned hole cutting. The whole film layer covers the bottom and sidewalls of the epitaxial structure 40, which provides better protection for the epitaxial structure 40.

[0060] For example, the epitaxial protective structure 30 is a film layer formed from one of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide; or,

[0061] The epitaxial protective structure 30 is a stack formed from multiple materials such as silicon oxide, silicon nitride, aluminum oxide, and titanium oxide.

[0062] Using the above-mentioned materials to make the epitaxial protective layer not only ensures that the epitaxial structure is not affected when the substrate is removed, but also that the above-mentioned materials have good waterproof performance and can protect the epitaxial structure from water and oxygen.

[0063] In this embodiment of the disclosure, the thickness of the epitaxial protective structure 30 is 0.1 to 5 micrometers. This thickness refers to the thickness between the inner wall and the outer wall of the epitaxial protective structure 30. This thickness can be either the bottom surface thickness or the side wall thickness.

[0064] In this implementation, the epitaxial protection structure formed by the above-mentioned thickness can achieve a good protection effect while also taking into account the miniaturization design suitable for micro LEDs.

[0065] For example, the thickness of the epitaxial protective structure 30 is 3 micrometers.

[0066] In this embodiment of the disclosure, the overall extensional protection structure 30 has a frustum-shaped structure, such as a frustum or truncated cone structure.

[0067] like Figure 1 As shown, the cross-section of the epitaxial protective structure 30 in the direction perpendicular to the light-emitting surface of the epitaxial structure is an inverted trapezoid.

[0068] In this embodiment of the present disclosure, the angle α between the bottom surface 31 of the extended protective structure 30 and the side wall 33 of the extended protective structure 30 is 60 to 120 degrees.

[0069] That is, Figure 1 The bottom angle of the cross section of the aforementioned epitaxial protective structure 30 in the direction perpendicular to the light-emitting surface of the epitaxial structure is 60 to 120 degrees.

[0070] In this implementation, the aforementioned angle design facilitates the continuous deposition of the epitaxial protective structure on the bottom and sidewalls of the epitaxial structure, thus forming the epitaxial protective structure.

[0071] For example, the angle between the bottom surface 31 of the extended protective structure 30 and the side wall 33 of the extended protective structure 30 can be 105 degrees.

[0072] See you again Figure 1 The light-emitting diode further includes a passivation layer 50.

[0073] The passivation layer 50 is located within the opening 32 of the epitaxial protection structure 30 and covers the epitaxial structure 40; the surface of the passivation layer 50 is flush with the top of the opening 32 of the epitaxial protection structure 30.

[0074] The top of the opening 32 is the side farther from the bottom surface 31, and the bottom of the opening 32 is the side closer to the bottom surface 31.

[0075] In this implementation, the passivation layer 50 works in conjunction with the epitaxial protection structure 30 to encapsulate the entire epitaxial structure 40, thus protecting the epitaxial structure 40. Furthermore, the surface of the passivation layer 50 is flush with the top of the opening in the epitaxial protection structure 30, ensuring the miniaturization of the light-emitting diode.

[0076] In this embodiment of the disclosure, the passivation layer 50 is a film formed from one of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide; or,

[0077] The passivation layer 50 is a stack of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide.

[0078] In one example, the passivation layer 50 is a reflective layer, and correspondingly, the epitaxial protective structure 30 is a transparent structure.

[0079] For example, the passivation layer 50 is a distributed Bragg reflector (DBR), which can be a stack of at least one periodic silicon oxide layer (e.g., SiO2) and titanium oxide layer (e.g., TiO2). The epitaxial protective structure 30 is a SiO2 layer.

[0080] When the passivation layer 50 is a reflective layer, the sidewalls of the epitaxial structure 40 of the epitaxial protective structure 30 can reduce the light emission from the sidewalls of the epitaxial structure 40 and enhance the brightness of the bottom light emission.

[0081] In another example, the passivation layer 50 is a transparent layer, and correspondingly, the epitaxial protection structure 30 is a reflective structure.

[0082] For example, the passivation layer 50 is a SiO2 layer. The epitaxial protection structure 30 is a DBR.

[0083] When the outer protective structure 30 is a reflective structure, due to its cup-shaped design, the reflection effect of the outer protective structure 30 is better, which can ensure the brightness of the emitted light.

[0084] In this embodiment of the disclosure, the epitaxial structure 40 includes a first semiconductor layer 401, an active layer 402, and a second semiconductor layer 403 stacked sequentially.

[0085] like Figure 1 As shown, the first semiconductor layer 401 is located at the bottom of the opening 32.

[0086] The second semiconductor layer 403 and the active layer 402 have stepped structures that extend to the first semiconductor layer 401.

[0087] In this embodiment of the disclosure, the first semiconductor layer 401 can be an N-type semiconductor layer, and the second semiconductor layer 403 can be a P-type semiconductor layer.

[0088] For example, the first semiconductor layer 401 can be an N-type gallium nitride layer, and the second semiconductor layer 403 can be a P-type gallium nitride layer.

[0089] In another example, the first semiconductor layer 401 can be a P-type semiconductor layer, and the second semiconductor layer 403 can be an N-type semiconductor layer.

[0090] In this embodiment of the disclosure, the active layer 402 can be a multi-quantum well layer, such as an InGaN / GaN multi-quantum well structure.

[0091] See Figure 1 The passivation layer 50 has a first through hole 501 and a second through hole 502. The first electrode 60 is connected to the first semiconductor layer 401 through the first through hole 501, and the second electrode 70 is connected to the second semiconductor layer 403 through the second through hole 502.

[0092] In the embodiments disclosed herein, the first electrode 60 and the second electrode 70 can both be one or more of Cr, Al, Ti, Al, Ti and Au stacked together.

[0093] Optionally, the light-emitting diode may further include a transparent conductive layer located between the second semiconductor layer 403 and the second electrode 70.

[0094] For example, the transparent conductive layer can be an indium tin oxide (ITO) layer.

[0095] Optionally, the light-emitting diode may also include a current blocking layer located between the transparent conductive layer and the second semiconductor layer.

[0096] It is worth noting that, in the embodiments of this disclosure, the structure can be selectively added or reduced based on the structure of the light-emitting diode described above, and this disclosure does not limit this.

[0097] Figure 2 This disclosure provides a flowchart of a method for fabricating a light-emitting diode (LED). See also... Figure 2 The method includes the following steps:

[0098] S11. An epitaxial film is formed on the first substrate.

[0099] S12. Bond the epitaxial film to the second substrate and remove the first substrate.

[0100] S13. The epitaxial film layer is patterned to obtain an epitaxial structure.

[0101] S14. An epitaxial protective structure is formed at the bottom and sidewall of the epitaxial structure. The epitaxial protective structure is a cup-shaped structure. The epitaxial structure is located inside the opening of the epitaxial protective structure and covers the bottom and sidewall of the epitaxial structure.

[0102] S15. A bonding layer is formed on the third substrate.

[0103] S16. Bond the bottom surface of the epitaxial protection structure to the bonding layer, and remove the second substrate. The opening of the epitaxial protection structure faces the side away from the third substrate.

[0104] In this embodiment, by placing the epitaxial structure within the opening of the cup-shaped epitaxial protective structure, the bottom of the cup-shaped epitaxial protective structure contacts the bonding layer during fabrication. When the substrate connected by the bonding layer needs to be removed, only the bonding layer and the epitaxial protective structure need to be separated, without affecting the epitaxial structure, thus ensuring the brightness and reliability of the epitaxial structure. Moreover, the aforementioned epitaxial protective structure covers the bottom and sidewalls of the epitaxial structure, further improving the reliability of the epitaxial structure.

[0105] Figure 3 A flowchart illustrating another method for fabricating a light-emitting diode (LED) according to an embodiment of this disclosure. See also... Figure 3 The method includes the following steps:

[0106] S21. A first semiconductor layer, an active layer, and a second semiconductor layer are sequentially formed on a first substrate, and the first semiconductor layer, the active layer, and the second semiconductor layer constitute an epitaxial film layer.

[0107] The first substrate can be a sapphire substrate.

[0108] In one example, step S21 includes:

[0109] The first step is to fabricate a first semiconductor layer on a first substrate.

[0110] In this embodiment of the disclosure, the first semiconductor layer is an N-type GaN layer.

[0111] The second step is to fabricate an active layer on the first semiconductor layer.

[0112] In this embodiment of the disclosure, the active layer is a multi-quantum well layer, such as an InGaN / GaN multi-quantum well layer.

[0113] The third step is to fabricate a second semiconductor layer on the active layer to obtain an epitaxial film layer.

[0114] In this embodiment of the disclosure, the second semiconductor layer is a P-type GaN layer.

[0115] In the embodiments disclosed herein, the above-mentioned semiconductor layer can be grown using a Veeco K465i or C4or RB MOCVD (Metal Organic Chemical Vapor Deposition) apparatus or an AIXTRON MOCVD apparatus. High-purity H2 (hydrogen), high-purity N2 (nitrogen), or a mixture of high-purity H2 and high-purity N2 is used as the carrier gas; high-purity NH3 is used as the N source; trimethylgallium (TMGa) and triethylgallium (TEGa) are used as gallium sources; trimethylindium (TMIn) is used as the indium source; silane (SiH4) is used as the N-type dopant; trimethylaluminum (TMAl) is used as the aluminum source; and magnesium pyrocene (CP2Mg) is used as the P-type dopant.

[0116] It is worth noting that other equipment can also be used to fabricate the aforementioned semiconductor layer, and this disclosure does not limit this.

[0117] Figure 4 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of this disclosure. See also... Figure 4 The first semiconductor layer 401, the active layer 402, and the second semiconductor layer 403 are sequentially stacked on the first substrate 111.

[0118] After the above fabrication is completed, the epitaxial film layer can be cleaned for subsequent fabrication.

[0119] S22. The epitaxial structure is patterned, and a passivation layer, a first electrode, and a second electrode are fabricated.

[0120] Figure 5 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of this disclosure. See also... Figure 5 First, a stepped structure is formed by etching, which extends from the second semiconductor layer 403 and the active layer 402 to the first semiconductor layer 401.

[0121] Then, a passivation layer 50 covering the stepped structure is fabricated. A first through hole 501 and a second through hole 502 are formed on the passivation layer 50, with the first through hole 501 corresponding to the bottom surface of the stepped structure and the second through hole 502 corresponding to the top surface of the stepped structure.

[0122] Then, a first electrode 60 and a second electrode 70 are fabricated. The first electrode 60 is connected to the first semiconductor layer 401 through a first through hole 501, and the second electrode 70 is connected to the second semiconductor layer 403 through a second through hole 502.

[0123] Optionally, a transparent conductive layer can be fabricated on the second semiconductor layer before fabricating the passivation layer 50.

[0124] In this step, although etching forms a stepped structure, it does not etch isolation trenches to separate different epitaxial structures.

[0125] S23. The epitaxial film layer is bonded to the second substrate on one side where the first electrode and the second electrode are located.

[0126] In this step, a photosensitive organic bonding layer is first spin-coated onto a second substrate; then, the epitaxial film layer is bonded to the photosensitive organic bonding layer.

[0127] The photosensitive organic bonding layer can be a photosensitive organic adhesive that can be decomposed by a 248nm or 266nm laser, which facilitates the subsequent separation of the second substrate.

[0128] The second substrate can be a sapphire substrate.

[0129] Figure 6 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of this disclosure. See also... Figure 6 After bonding, the passivation layer 50, the first electrode 60 and the second electrode 70 are bonded together with the second substrate 113 through the photosensitive bonding layer 112. At this time, there are no voids between the epitaxial film and the second substrate 113.

[0130] S24. Remove the first substrate.

[0131] In this step, the first substrate is removed by laser stripping and surface residues are removed by acid washing.

[0132] Figure 7 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of this disclosure. See also... Figure 7 After removing the first substrate 111, the first semiconductor layer 401 of the epitaxial film is exposed.

[0133] S25. The epitaxial film layer is patterned to obtain an epitaxial structure.

[0134] In this step, photoresist is applied to the surface of the first semiconductor layer, and photolithography is performed according to the die (individual LED chip) size to form a patterned photoresist pattern. The photoresist pattern exposes the predetermined walkway positions on the surface of the first semiconductor layer. Then, inductively coupled plasma (ICP) etching is performed to etch through the spaces between the dies.

[0135] During the etching process, the etching procedure is designed to utilize the etching rate difference between the photosensitive organic bonding layer and the epitaxial film and passivation layer to ensure a larger spacing between the photosensitive organic bonding layers.

[0136] That is, the spacing between the photosensitive organic bonding layers below the adjacent epitaxial structures is 2 to 10 micrometers larger than the spacing between the adjacent epitaxial structures, for example, 5 micrometers.

[0137] The spacing between adjacent epitaxial structures can refer to the distance between the contact surface of the adjacent epitaxial structure and the photosensitive organic bonding layer.

[0138] This is beneficial because when fabricating the epitaxial protection structure later, some of the epitaxial protection material will be formed on the second substrate, and can be removed together by removing the second substrate.

[0139] Figure 8 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of this disclosure. See also... Figure 8 Through etching, multiple epitaxial structures 40 are formed. These epitaxial structures 40 have a frustum-like structure, such as a frustum of a cone or a truncated pyramid. The cross-section of the epitaxial structure 40 perpendicular to the second substrate 113 is trapezoidal. The photosensitive bonding layer 112 is recessed inward by a depth d relative to the epitaxial structure 40, forming a larger spacing than the adjacent epitaxial structures 40. The recess d, i.e., the difference in spacing, is 2–10 micrometers.

[0140] S26. An epitaxial protective structure is formed at the bottom and sidewalls of the epitaxial structure.

[0141] In this step, an epitaxial protective structure is fabricated on the bottom and sidewalls of the epitaxial structure and the sidewalls of the passivation layer using plasma-enhanced chemical vapor deposition (PECVD) or ion-assisted evaporation techniques.

[0142] For example, a film formed of one of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide is deposited on the bottom and sidewalls of the epitaxial structure and on the sidewalls of the passivation layer; or, a stack of multiple of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide is deposited on the bottom and sidewalls of the epitaxial structure and on the sidewalls of the passivation layer.

[0143] Figure 9 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of this disclosure. See also... Figure 9 The epitaxial protection structure 30 is a cup-shaped structure. The bottom surface 31 of the epitaxial protection structure 30 covers the first semiconductor layer 401, and the sidewalls 33 of the epitaxial protection structure 30 wrap around the sidewalls of the epitaxial structure 40 and the passivation layer 50. The opening of the epitaxial protection structure 30 faces the second substrate 113, and the surface of the passivation layer 50 is flush with the top of the opening of the epitaxial protection structure 30.

[0144] In addition, when fabricating the epitaxial protection structure 30, part of the epitaxial protection material 310 falls onto the second substrate 113 between the photosensitive bonding layers 112. The aforementioned recessed design ensures that the epitaxial protection material 310 does not contact the photosensitive bonding layers 112.

[0145] In this embodiment of the disclosure, the thickness of the epitaxial protective structure 30 is 0.1 to 5 micrometers.

[0146] In this implementation, the epitaxial protection structure formed by the above-mentioned thickness can achieve a good protection effect while also taking into account the miniaturization design suitable for micro LEDs.

[0147] For example, the thickness of the epitaxial protective structure 30 is 3 micrometers.

[0148] In this embodiment of the disclosure, the overall extensional protection structure 30 has a frustum-shaped structure, such as a frustum or truncated cone structure.

[0149] like Figure 9 As shown, the epitaxial protection structure 30 has a trapezoidal cross-section in the direction perpendicular to the second substrate.

[0150] In this embodiment of the disclosure, the angle between the bottom surface 31 of the extended protective structure 30 and the side wall 33 of the extended protective structure 30 is 60 to 120 degrees.

[0151] That is, Figure 9 The aforementioned epitaxial protection structure 30 has a vertices angle of 60 to 120 degrees in the cross section perpendicular to the second substrate direction.

[0152] In this implementation, the aforementioned angle design facilitates the continuous deposition of the epitaxial protective structure on the bottom and sidewalls of the epitaxial structure, thus forming the epitaxial protective structure.

[0153] For example, the angle between the bottom surface 31 of the extended protective structure 30 and the side wall 33 of the extended protective structure 30 can be 105 degrees.

[0154] In this embodiment of the disclosure, the passivation layer 50 is a film formed from one of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide; or,

[0155] The passivation layer 50 is a stack of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide.

[0156] In one example, the passivation layer 50 is a reflective layer, and correspondingly, the epitaxial protective structure 30 is a transparent structure.

[0157] For example, the passivation layer 50 is a DBR. The epitaxial protection structure 30 is a SiO2 layer.

[0158] When the passivation layer 50 is a reflective layer, the sidewalls of the epitaxial structure 40 of the epitaxial protective structure 30 can reduce the light emission from the sidewalls of the epitaxial structure 40 and enhance the brightness of the bottom light emission.

[0159] In another example, the passivation layer 50 is a transparent layer, and correspondingly, the epitaxial protection structure 30 is a reflective structure.

[0160] For example, the passivation layer 50 is a SiO2 layer. The epitaxial protection structure 30 is a DBR.

[0161] When the outer protective structure 30 is a reflective structure, due to its cup-shaped design, the reflection effect of the outer protective structure 30 is better, which can ensure the brightness of the emitted light.

[0162] S27. A bonding layer is formed on the third substrate.

[0163] In the embodiments of this disclosure, the third substrate can be any one of sapphire substrate, Si substrate, SiC substrate, etc., and this disclosure does not limit the material of the substrate.

[0164] For example, the third substrate is a sapphire substrate.

[0165] In this step, an organic bonding layer is spin-coated onto a third substrate.

[0166] For example, the bonding layer is an organic adhesive material layer.

[0167] S28. Bond the bottom surface of the epitaxial protective structure to the bonding layer.

[0168] Figure 10 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of this disclosure. See also... Figure 10 The bottom surface 31 of the epitaxial protective structure 30 is bonded to the third substrate 10 through the bonding layer 20.

[0169] S29. Remove the second substrate.

[0170] In this step, the second substrate is removed by laser lift-off, and the residue between the chips is cleaned by ICP or plasma to form the desired micro LED chip.

[0171] Figure 11 This is a schematic diagram of the structure during the fabrication process of a light-emitting diode according to an embodiment of this disclosure. See also... Figure 11 After removing the second substrate 113 and the photosensitive bonding layer 112, the third substrate 10 is connected to the bottom surface 31 of the plurality of epitaxial protection structures 30 through the bonding layer 20. The epitaxial protection material 310 on the second substrate 113 is also removed together with the second substrate 113.

[0172] After step S29, the epitaxial structure and epitaxial protection structure can be separated by thinning the third substrate, dicing, or other methods.

[0173] Furthermore, the third substrate can be peeled off to remove the bonding layer. In this case, due to the protection of the epitaxial protective structure, the process will not affect the epitaxial structure.

[0174] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A light-emitting diode, characterized in that, The light-emitting diode includes: an epitaxial protection structure (30), an epitaxial structure (40), a first electrode (60), and a second electrode (70); The first electrode (60) and the second electrode (70) are respectively connected to the epitaxial structure (40); The epitaxial protective structure (30) is a cup-shaped structure, and the epitaxial structure (40) is located inside the opening (32) of the epitaxial protective structure (30). The epitaxial protective structure (30) covers the bottom and sidewalls of the epitaxial structure (40).

2. The light-emitting diode according to claim 1, characterized in that, The epitaxial protective structure (30) is a film layer attached to the bottom and sidewalls of the epitaxial structure (40); The epitaxial protective structure (30) is a film layer formed from one of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide; or, The epitaxial protective structure (30) is a stack formed from a variety of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide.

3. The light-emitting diode according to claim 1, characterized in that, The thickness of the epitaxial protective structure (30) is 0.1 to 5 micrometers.

4. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The angle between the bottom surface (31) of the extended protective structure (30) and the side wall (33) of the extended protective structure (30) is 60 to 120 degrees.

5. The light-emitting diode according to any one of claims 1 to 3, characterized in that, The light-emitting diode further includes: a passivation layer (50); The passivation layer (50) is located within the opening (32) of the epitaxial protection structure (30) and covers the epitaxial structure (40); The surface of the passivation layer (50) is flush with the top of the opening (32) of the epitaxial protection structure (30).

6. A method for fabricating a light-emitting diode, characterized in that, The method includes: An epitaxial film is formed on the first substrate; The epitaxial film is bonded to the second substrate, and the first substrate is removed; The epitaxial film is patterned to obtain an epitaxial structure; An epitaxial protective structure is formed at the bottom and sidewalls of the epitaxial structure. The epitaxial protective structure is a cup-shaped structure. The epitaxial structure is located inside the opening of the epitaxial protective structure and covers the bottom and sidewalls of the epitaxial structure. A bonding layer is formed on the third substrate; The bottom surface of the epitaxial protection structure is bonded to the bonding layer, and the second substrate is removed. The opening of the epitaxial protection structure faces the side away from the third substrate.

7. The method for fabricating a light-emitting diode according to claim 6, characterized in that, Bonding the epitaxial film to the second substrate includes: A photosensitive organic bonding layer is spin-coated onto the second substrate; The epitaxial film is bonded together with the photosensitive organic bonding layer.

8. The method for fabricating a light-emitting diode according to claim 7, characterized in that, The epitaxial film layer is patterned, including: The epitaxial film and the photosensitive organic bonding layer are etched such that the spacing between the photosensitive organic bonding layers under the adjacent epitaxial structures is 2 to 10 micrometers larger than the spacing between the adjacent epitaxial structures.

9. The method for fabricating a light-emitting diode according to any one of claims 6 to 8, characterized in that, An epitaxial protective structure is formed at the bottom and sidewalls of the epitaxial structure, including: A film layer formed of one of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide is deposited on the bottom and sidewalls of the epitaxial structure; or, a stack of multiple of silicon oxide, silicon nitride, aluminum oxide, and titanium oxide is deposited on the bottom and sidewalls of the epitaxial structure.

10. The method for fabricating a light-emitting diode according to any one of claims 6 to 8, characterized in that, The method further includes: Before the epitaxial film is bonded to the second substrate, a passivation layer is formed on the epitaxial film; After the epitaxial protection structure is formed, the passivation layer is located inside the opening of the epitaxial protection structure, and the surface of the passivation layer is flush with the top of the opening of the epitaxial protection structure.

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