Light emitting diode, semiconductor structure and display device

Abstract

The invention provides a light emitting diode, a semiconductor structure and a display device. The light-emitting diode comprises a semiconductor light-emitting laminated layer, a metal laminated layer structure and a conductive layer. The metal laminated structure includes a magnetic metal layer. The side, away from the active layer, of the second semiconductor layer of the semiconductor light-emitting laminated layer is the front face of the semiconductor light-emitting laminated layer, the side, away from the active layer, of the first semiconductor layer is the back face of the semiconductor light-emitting laminated layer, and the conductive layer is located on the back face of the semiconductor light-emitting laminated layer and is insulated from the first semiconductor layer through the U-shaped layer. The conductive layer enables the bottom of the light-emitting diode to be conductive, so that an electric field can act on the back of the light-emitting diode simultaneously, and the magnetic metal enables the front of the light-emitting diode to be subjected to interaction of magnetic force and the electric field, so that the front and the back of the light-emitting diode are stressed. The light-emitting diode is prevented from overturning during magnetic transfer, and the transfer yield is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and particularly to a light-emitting diode, a semiconductor structure, and a display device. Background Art

[0002] Micro-LED is a new generation of display technology. Compared with traditional LEDs, it has the same light-emitting principle, but the scale of a single LED is less than 100 μm, which greatly improves the difficulty of its preparation. Among them, the mass transfer technology is the key. To adapt to large-area displays, a large number of LEDs need to be transferred from a sapphire substrate to a glass plate. The traditional "pick and place" method is too inefficient to transfer a large area in a short time.

[0003] Currently, there is a chip transfer method in which a magnetic metal component is provided in the electrode structure of the chip. The chip is placed in an electric field and a magnetic field environment, and the magnetic field and electric field intensities are controlled during transfer to cause the chip to move to a fixed position on the substrate under the action of magnetic force and electric force, thereby realizing chip transfer. However, on the one hand, the magnetic metal on the existing chip is easily damaged during the chip preparation process, affecting the reliability and transfer yield of the chip; on the other hand, since the magnetic electrode is located on the electrode side of the chip, the opposite back side is usually a non-conductive adhesive material, which results in the chip being only attracted by electric force on the electrode side, and not being attracted by electric force on the back side, and thus it is easy to cause the chip to flip during the transfer process, resulting in the chip facing downwards and causing transfer failure, thereby reducing the transfer yield. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a light-emitting diode, a semiconductor structure, and a display device to ensure the reliability and transfer yield of the chip structure.

[0005] To achieve the above purpose and other related purposes, an embodiment of the present invention provides a light-emitting diode, which at least includes:

[0006] A semiconductor light-emitting stack, including a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type stacked in sequence. The side of the second semiconductor layer away from the active layer is the front of the semiconductor light-emitting stack, and the side of the first semiconductor layer away from the active layer is the back of the semiconductor light-emitting stack;

[0007] A metal stack structure, disposed on the front of the semiconductor light-emitting stack, the metal stack structure including a magnetic metal layer; a conductive layer, located on the back of the semiconductor light-emitting stack, the conductive layer being a semiconductor layer of the second conductivity type;

[0008] The U-shaped layer is located between the conductive layer and the first semiconductor layer.

[0009] Another aspect of the present invention provides a semiconductor structure, comprising:

[0010] A carrier substrate provided with a plurality of carrier portions;

[0011] A plurality of light-emitting units, each of which is carried on one of the carrier portions; wherein

[0012] The light-emitting unit includes a light-emitting diode provided in an embodiment of the present application by magnetic transfer, and the back side of the semiconductor light-emitting stack of the light-emitting diode faces the carrier portion.

[0013] According to another aspect of the present invention, there is also provided a display device, comprising a packaging substrate and at least one light-emitting diode provided on the packaging substrate, and the light-emitting diode includes a light-emitting diode provided in an embodiment of the present application by magnetic transfer.

[0014] Compared with the prior art, the light-emitting diode, semiconductor structure and display device of the present invention at least have the following beneficial effects:

[0015] The light-emitting diode of the present invention includes a semiconductor light-emitting stack, a metal stack structure and a conductive layer. The metal stack structure includes a magnetic metal layer. The side of the second semiconductor layer of the second conductivity type of the semiconductor light-emitting stack away from the active layer is the front of the semiconductor light-emitting stack, and the side of the first semiconductor layer of the first conductivity type away from the active layer is the back of the semiconductor light-emitting stack. The conductive layer formed into the semiconductor layer of the second conductivity type is located on the back of the semiconductor light-emitting stack and is insulated from the first semiconductor layer by a U-shaped layer. The conductive layer enables the bottom of the light-emitting diode to conduct electricity, so that the electric field can act on the back of the light-emitting diode at the same time, while the magnetic metal enables the front of the light-emitting diode to be subjected to the interaction of magnetic force and electric field, so that both the front and back of the light-emitting diode are stressed, preventing the light-emitting diode from flipping during magnetic transfer and improving the transfer yield. In addition, since the first metal layer in the magnetic metal layer of the light-emitting diode of the present invention is an inert metal layer, the inert metal layer can block the corrosion of the etching solution in subsequent processes, and thus can protect the metal stack structure. The top layer and the bottom layer of the metal stack structure are both the first metal layer, so that the first metal layer coats the magnetic metal layer to achieve protection of the magnetic metal layer, avoiding the peeling off of the electrode layer formed on the metal stack structure subsequently, and improving the reliability of the light-emitting diode.

[0016] The semiconductor device and display device of the present invention include the above-mentioned light-emitting diode transferred by magnetic force, and they also have good transfer yield and stability. Description of the Drawings

[0017] Figure 1 Shown is a schematic structural diagram of a light-emitting diode provided in Embodiment 1 of the present invention.

[0018] Figure 2 Shown as Figure 1 an enlarged schematic diagram at the position of the light-emitting diode S in

[0019] Figure 3 Shown as Figure 1 another enlarged schematic diagram of the metal stack structure in

[0020] Figure 4 Shown is a schematic structural diagram of a light-emitting diode provided in Embodiment 2 of the present invention.

[0021] Figure 5 Shown is a schematic structural diagram of a light-emitting diode provided in Embodiment 3 of the present invention.

[0022] Figure 6 Shown is a top-view structural schematic diagram of a light-emitting diode provided in Embodiment 4 of the present invention.

[0023] Figure 7 Shown as a cross-sectional schematic diagram along the Figure 6 A-A direction in

[0024] Figure 8 Shown is a schematic structural diagram of a light-emitting diode provided in Embodiment 5 of the present invention.

[0025] Figure 9 Shown is a schematic structural diagram of a display device provided in Embodiment 6 of the present invention.

[0026] List of reference numerals:

[0027] 101, semiconductor light-emitting stack; 1011, first semiconductor layer; 1012, active layer; 1013, second semiconductor layer; 102, conductive layer; 103, U-shaped layer; 104, first mesa structure; 105, second mesa structure; 110, front side; 120, back side; 106, first electrode; 1061, first electrode layer; 1062, first contact electrode; 1063, metal stack structure; 631, first metal layer; 632, second metal layer; 107, second electrode; 1071, second electrode layer; 1072, second contact electrode; 108, passivation layer.

[0028] 109, growth substrate; 200, bonding substrate; 201, insulating bonding layer; 202, insulating dissociation layer.

[0029] 800, semiconductor structure; 801, carrier substrate; 802, carrier portion; 803, light-emitting unit.

[0030] 900, Display device; 901, Encapsulation substrate; 902, Reflection structure; 903, Light-emitting diode. Detailed implementation

[0031] The following specific embodiments illustrate the implementation manners 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 implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0032] It should be noted that the diagrams provided in the embodiments of the present invention only illustrate the basic concept of the present invention in a schematic manner. Although only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation, the form, number, and proportion of each component in actual implementation can be changed arbitrarily, and the layout form of its components may also be more complex. The structures, proportions, sizes, etc. shown in the accompanying drawings of the specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the implementation conditions that can be implemented by this application. Therefore, they do not have technical substance significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in this application.

[0033] The inventor's research found that when a magnetic metal structure is provided in the electrode structure, and the back surface of the chip opposite to the electrode is a non-conductive material layer, when the chip with the above structure is magnetically transferred, the chip is only attracted by electricity on the electrode side, and the back surface cannot be attracted by electricity. Therefore, it is very easy for the chip to flip during the transfer process, resulting in transfer failure and reducing the transfer yield.

[0034] To solve the above technical problems in the prior art, the present invention provides a light-emitting diode, a semiconductor structure, and a display device, which can improve the reliability of the magnetic light-emitting diode, and improve the transfer yield and efficiency.

[0035] Specifically, an embodiment of the present invention provides a light-emitting diode, which at least includes:

[0036] A semiconductor light-emitting stack, including a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type stacked in sequence. The side of the second semiconductor layer away from the active layer is the front surface of the semiconductor light-emitting stack, and the side of the first semiconductor layer away from the active layer is the back surface of the semiconductor light-emitting stack;

[0037] A metal stack structure is disposed on the front surface of the semiconductor light-emitting stack, and the metal stack structure includes a magnetic metal layer;

[0038] A conductive layer is located on the back surface of the semiconductor light-emitting stack, and the conductive layer is a semiconductor layer of a second conductive type;

[0039] A U-shaped layer is located between the conductive layer and the first semiconductor layer.

[0040] As described above, in this embodiment, a conductive layer is disposed on the back surface of the semiconductor light-emitting stack of the light-emitting diode, and a U-shaped layer is disposed between the conductive layer and the first semiconductor layer, so that the bottom of the light-emitting diode can conduct electricity and is insulated from the semiconductor light-emitting stack at the same time. Thus, the electric field can act on the back surface of the light-emitting diode at the same time, and the magnetic metal makes the front surface of the light-emitting diode subject to the interaction of magnetic force and electric field. As a result, both the front and back surfaces of the light-emitting diode are stressed, preventing the light-emitting diode from flipping during magnetic force transfer and improving the transfer yield.

[0041] Optionally, the conductive layer is an AlGaInP layer doped with Mg, C or Zn.

[0042] Optionally, the P-type doping concentration of the conductive layer is between 2E18 atoms / cm 3 ~4.5E18 atoms / cm 3 .

[0043] Optionally, the first semiconductor layer is an AlGaInP layer doped with Si.

[0044] The above conductive layer is a doped layer, and the dopant is beneficial to improving its conductivity and meeting the conductive requirements. In addition, the setting of the doping concentration is also beneficial to improving its conductivity. In addition, the first semiconductor layer and the conductive layer are semiconductor layers of different conductive types, and are of the same type as the second semiconductor layer, so that the electric field can act on the conductive layer. The above conductive layer can be formed by deposition and doping processes when forming the semiconductor light-emitting stack, which is compatible with the manufacturing process of the semiconductor light-emitting stack and does not increase the manufacturing cost.

[0045] Optionally, the thickness of the conductive layer is 20%-25% of the thickness of the first semiconductor layer.

[0046] Optionally, the thickness of the conductive layer is between 0.5 μm and 1.5 μm.

[0047] The thickness setting of the conductive layer can meet its doping and conductive requirements, and at the same time control the conductive layer not to be too thick to avoid affecting the overall thickness of the light-emitting diode.

[0048] Optionally, the U-shaped layer is an undoped AlGaInP layer.

[0049] Optionally, the thickness of the U-shaped layer ranges from 0.5 μm to 1.5 μm.

[0050] By forming the above-mentioned undoped or unintentionally doped AlGaInP layer and setting its thickness as above, electrical isolation between the conductive layer and the semiconductor light-emitting stack, especially the first semiconductor layer, is achieved. On the one hand, the electric field effect is realized, and on the other hand, damage to the first semiconductor layer is avoided, which is also beneficial to controlling the overall thickness of the light-emitting diode.

[0051] Optionally, the sidewall of the light-emitting diode is an inclined sidewall, and the angle between the sidewall and the plane where the substrate is located ranges from 70° to 90°.

[0052] The setting of the angle of the sidewall of the light-emitting diode makes the upper and lower weights of the light-emitting diode not differ too much, which is beneficial to ensuring the stress uniformity of the light-emitting diode and improving the transfer yield of the light-emitting diode.

[0053] Optionally, the second semiconductor layer, the active layer, and a part of the first semiconductor layer are etched downward in sequence from a part of the surface of the front side, and the exposed first semiconductor layer after etching is formed into a first mesa structure; the unetched second semiconductor layer, active layer, and the corresponding part of the first semiconductor layer are formed into a second mesa structure, and the metal stack structure is disposed above the first mesa structure.

[0054] Optionally, the metal stack structure includes a first metal layer and a second metal layer arranged alternately; wherein, the first metal layer is an inert metal layer, and the second metal layer is a magnetic metal layer; the layers closest to and farthest from the first mesa structure in the metal stack structure are both the first metal layer, and the thickness of the layer closest to the first mesa structure is less than the thickness of the layer farthest from the first mesa structure.

[0055] The first metal layer, which is an inert metal layer, covers the second metal layer, which is a magnetic metal layer. Therefore, the inert metal layer can block the corrosion of the etching solution in subsequent processes, and thus can protect the metal stack structure.

[0056] Optionally, the cross-sectional area of the metal stack structure gradually decreases in the direction away from the first mesa structure, and the angle between the inner sidewall of the metal stack structure and the surface of the first mesa structure ranges from 30° to 50°.

[0057] The above setting of the metal stack structure can achieve better metal bonding force, buffer the structural stress at the same time, and improve the stability of the structure.

[0058] Optionally, the proportion of the volume of the magnetic metal layer in the volume of the light-emitting diode ranges from 0.4% to 1.2%.

[0059] The volume of the magnetic metal layer in the metal stack is set so as to enable effective transfer of the chip under a magnetic field or an electric field.

[0060] Optionally, the height difference between the first mesa structure and the second mesa structure occupies 1 / 3 to 1 / 2 of the height of the semiconductor light-emitting stack.

[0061] Optionally, the height difference between the first mesa structure and the second mesa structure is between 2.5 μm and 2.8 μm, and the height of the semiconductor light-emitting stack is between 3 μm and 6 μm.

[0062] The height settings of the semiconductor light-emitting stack, the first mesa structure, and the second mesa structure are also beneficial to cooperate with chip transfer and improve chip transfer efficiency.

[0063] Optionally, the light-emitting diode further includes:

[0064] A first electrode layer, disposed on the first mesa, and electrically connected to the first semiconductor layer;

[0065] A second electrode layer, disposed on the metal stack structure of the second mesa structure, and electrically connected to the second semiconductor layer.

[0066] Optionally, the materials of the first electrode layer and the second electrode layer are transparent conductive materials.

[0067] The setting of the first electrode layer and the second electrode layer and the material selection can reduce the influence of the electrode layer on light output and improve its light output effect on the premise of ensuring the normal operation of the light-emitting diode.

[0068] Optionally, the first electrode layer further extends and covers the side wall of the first mesa structure on the side away from the second mesa structure, and the end of the first electrode layer on the side wall does not exceed the interface between the U-shaped layer and the first semiconductor layer; the second electrode layer extends from the surface of the second mesa structure and covers the side wall of the second mesa structure, and the second electrode layer is insulated from the conductive layer.

[0069] The designs of the first electrode layer and the second electrode layer can be adjusted according to actual needs, which is beneficial to adapting to the circuit connection of subsequent packaging and improving the yield of the circuit design after transfer.

[0070] Optionally, a passivation layer is further disposed on the surface and side wall of the second mesa structure, and the second electrode layer is formed on the passivation layer.

[0071] The passivation layer can effectively protect the semiconductor light-emitting stack from external damage and at the same time insulate the first electrode layer from other layer structures of the semiconductor light-emitting stack.

[0072] Optionally, the light-emitting diode further includes a substrate, which is a growth substrate for the semiconductor light-emitting stack; or the substrate is a bonding substrate, and there is an insulating bonding layer between the bonding substrate and the conductive layer.

[0073] The provision of the substrate can improve the stability of the light-emitting diode and is also conducive to improving the reliability of the light-emitting diode during the transfer process.

[0074] Another embodiment of the present application provides a semiconductor structure, which includes:

[0075] A carrier substrate provided with a plurality of carrier portions;

[0076] A plurality of light-emitting units, each of which is carried on the corresponding carrier portion; where

[0077] The light-emitting unit includes a light-emitting diode according to an embodiment of the present application transferred by magnetism, and the back side of the semiconductor light-emitting stack of the light-emitting diode faces the carrier portion.

[0078] Another embodiment of the present application provides a display device, which includes a packaging substrate and at least one light-emitting diode disposed on the packaging substrate, and the light-emitting diode includes a light-emitting diode according to an embodiment of the present application transferred by magnetism.

[0079] Optionally, the light-emitting diode is fixed to the packaging substrate from the back side, the front side is the light-emitting side, and a reflection structure is further provided between the light-emitting diode and the packaging substrate.

[0080] The provision of the reflection structure can reflect the light emitted from the back side of the light-emitting diode to the front side for emission, improve the light-emitting effect of the light-emitting diode, and further improve the display effect of the display device.

[0081] The present invention will be described in detail below with specific embodiments.

[0082] Embodiment 1

[0083] This embodiment provides a light-emitting diode, such as Figure 1As shown in the figure, the light-emitting diode includes a semiconductor light-emitting stack 101, a metal stack structure 1063 located on the front surface 110 of the semiconductor light-emitting stack 101, a conductive layer 102 located on the back surface 120 of the semiconductor light-emitting stack 101, and a U-shaped layer 103 located between the conductive layer 102 and the semiconductor light-emitting stack 101. Among them, the metal stack structure 1063 includes a magnetic metal layer. The metal stack structure 1063 with magnetism is used to cooperate with the magnetic field and electric field in the transfer environment during subsequent chip transfer. The conductive layer 102 enables the back surface 120 of the light-emitting diode to conduct electricity, and thus can be affected by the electric field force. The magnetic metal layer and the conductive layer 102 make the front surface 110 and the back surface 120 of the light-emitting diode be stressed simultaneously, realizing the transfer of the light-emitting diode under the action of the magnetic field force and the electric field force. At the same time, it prevents the light-emitting diode from flipping during magnetic transfer, improving the transfer yield.

[0084] Specifically, referring to Figure 1 , the semiconductor light-emitting stack 101 is the light-emitting structure of the light-emitting diode. The semiconductor light-emitting stack 101 includes a first semiconductor layer 1011 of a first conductivity type, an active layer 1012, and a second semiconductor layer 1013 of a second conductivity type, which are stacked in sequence from bottom to top. The first semiconductor layer 1011 can be an N-type semiconductor layer, and the second semiconductor layer 1013 can be a P-type semiconductor layer. The first semiconductor layer 1011 is used to provide electrons for recombination and light emission, and the second semiconductor layer 1013 is used to provide holes for recombination and light emission. The active layer 1012 is a single quantum well or multi-quantum well structure, which is used for recombination and light emission of electrons and holes. Of course, it is also possible that the first semiconductor layer 1011 is a P-type semiconductor layer and the second semiconductor layer 1013 is an N-type semiconductor layer. In this embodiment, the side of the second semiconductor layer 1013 away from the active layer 102 is used as the front surface 110 of the semiconductor light-emitting stack 101, and the side of the first semiconductor layer 1011 away from the active layer 1012 is used as the back surface 120 of the semiconductor light-emitting stack 100.

[0085] Similarly referring to Figure 1 , the semiconductor light-emitting stack 100 is formed with a first mesa structure 104 and a second mesa structure 105. Specifically, from the partial surface on the front surface 110 side of the semiconductor light-emitting stack 101, the second semiconductor layer 1031, the active layer 1012, and a part of the first semiconductor layer 1011 are etched downward in sequence. The exposed part of the first semiconductor layer 1011 after etching is formed into the first mesa structure 104. The remaining unetched second semiconductor layer 1013, active layer 1012, and the corresponding part of the first semiconductor layer 1011 are formed into the second mesa structure 105. In this embodiment, referring to Figure 1, the second mesa structure 105 and the first mesa structure 104 are arranged side by side. In an alternative embodiment, the angle α between the sidewalls of the semiconductor light-emitting stack 101 (specifically, the sidewalls of the first mesa structure 104 away from the second mesa structure 105 and the sidewalls of the second mesa structure 105 away from the first mesa structure 104) and the plane of the back surface 120 of the semiconductor light-emitting stack 101 is between 70° and 90°, for example, 80°, 85°, etc. The setting of the sidewall angle of the semiconductor light-emitting stack 101 makes the upper and lower weights of the light-emitting diode not differ too much, which is beneficial to ensuring the force uniformity of the light-emitting diode and improving the transfer yield of the light-emitting diode. Optionally, the height difference between the first mesa structure 104 and the second mesa structure 105 occupies 1 / 3 to 1 / 2 of the height of the entire semiconductor light-emitting stack 100, and this height difference setting is also beneficial to cooperating with chip transfer and improving chip transfer efficiency. For example, the height difference H1 between the first mesa structure 104 and the second mesa structure 105 is between 2.5 μm and 2.8 μm, and the height H2 of the semiconductor light-emitting stack 101 is between 3 μm and 6 μm, for example, 3.5 μm, 4.5 μm, 5 μm, 6 μm, etc.

[0086] Similarly referring to Figure 1 , in this embodiment, the conductive layer 102 is located on the back surface 120 side of the semiconductor light-emitting stack 101, and a U-shaped layer 103 is further formed between the conductive layer 102 and the semiconductor light-emitting stack 101. The above-mentioned conductive layer 102 is a doped semiconductor layer. As described above, in this embodiment, the first semiconductor layer 1011 is an N-type semiconductor layer, specifically, an Si-doped AlGaInP layer, and the Si doping concentration is between 1E18 atoms / cm 3 to 2E18 atoms / cm 3 , the thickness H3 of the first semiconductor layer 1011 is between 1 μm and 3 μm, for example, between 1.5 μm and 2.5 μm, between 2 μm and 2.8 μm. The conductive layer 102 is a P-type doped layer, such as AlGaInP doped with Mg, C, or Zn, preferably Mg-doped AlGaInP. By performing P-type doping, the conductivity of the conductive layer 102 can be improved to meet the requirements of the electric field action. In addition, the thickness H4 of the conductive layer 102 is 20% to 25% of the thickness H3 of the above-mentioned first semiconductor layer 1011. Further, the above H4 is between 0.5 μm and 1.5 μm, for example: 0.8 μm, 1 μm, 1.2 μm. The thickness setting of the conductive layer 102 does not affect the overall thickness of the light-emitting diode, that is, it can ensure that the semiconductor light-emitting stack 101 has sufficient thickness design space. At the same time, it can ensure that the conductive layer 102 has sufficient thickness to meet the doping requirements and ensure its conductivity.

[0087] As Figure 1As shown, the U-shaped layer 103 is located between the semiconductor light-emitting stack 101 and the conductive layer 102. Specifically, it is located between the side of the first semiconductor layer 1011 away from the active layer 1012 and the conductive layer 102. The U-shaped layer 103 is an undoped AlGaInP layer with a thickness ranging from 0.5 μm to 1.5 μm, such as 0.7 μm, 1.2 μm, 1.5 μm. The setting of the U-shaped layer 103 ensures the insulation between the conductive layer 102 and the first semiconductor layer 1011. Thus, when an electric field is applied, it can ensure that the first semiconductor layer 1011 is not damaged or broken down by the electric field.

[0088] As described above, the first semiconductor layer 1011 is an N-type semiconductor layer. Specifically, it is an Si-doped AlGaInP layer. It can be understood that the first semiconductor layer 1011 is a multi-layer structure. For example, in the direction gradually away from the conductive layer 102, the first semiconductor layer 1011 includes an N-type buffer layer (such as a GaAs layer), an N-type window layer (such as Si-doped AlGaInP), an N-type cover layer (such as an Si-doped AlInP layer), and an N-type confinement layer (such as an AlInP / AlGaInP composite layer) stacked in sequence. The setting of the N-type buffer layer can reduce the lattice matching defects between the semiconductor light-emitting stack 101 and the substrate and improve the epitaxial growth quality; the N-type window layer is conducive to the lateral expansion of current on the first semiconductor layer 1011; the N-type cover layer is doped with a sufficient concentration of Si to provide electrons for photoelectric recombination; the N-type confinement layer is disposed adjacent to the active layer 1012 and can block Si from entering the active layer 1012 and affecting the performance of the active layer 1012. Similarly, in the direction away from the active layer 1012, the second semiconductor layer 1013 (i.e., the P-type semiconductor layer) is sequentially stacked with a P-type confinement layer (such as an AlInP / AlGaInP composite layer), a P-type cover layer (such as an Mg-doped AlInP layer), a transition layer (such as an AlGaInP layer), a P-type window layer (a GaP layer), and a P-type ohmic contact layer (a highly doped GaP layer). The P-type confinement layer is disposed adjacent to the active layer 1012 and can block Mg from entering the active layer 1012 and affecting the performance of the active layer 1012; the P-type cover layer is doped with Mg to provide holes required for photoelectric recombination to the active layer 1012; the transition layer connects the P-type cover layer and the P-type window layer and is conducive to improving the lattice quality of GaP; the P-type window layer is used to enhance the uniformity of current expansion and is conducive to improving the lateral expandability of current in the P-type layer; the P-type ohmic contact layer is used to form an ohmic contact with the subsequent electrode material. The active layer 1012 is a multi-quantum well structure, which includes multiple pairs of well layers and barrier layers. The materials of the well layers and barrier layers are (Al y Ga (1-y) ) z In (1-z)P, where 0 < y < 1 and 0 < z < 1. By adjusting different value ranges of y and z in the well layer and the barrier layer, a light-emitting diode structure with a green to red light-emitting wavelength of 560 - 650 nm is obtained. In this embodiment, the well layer is preferably (Al y Ga (1-y) ) 0.5 In 0.5 P, where 0 < y ≤ 0.15; the barrier layer is (Al y Ga (1-y) ) 0.5 In 0.5 P, where 0.5 < y < 1, and the emission wavelength is between 615 nm and 625 nm.

[0089] Referring again to Figure 1 , the light-emitting diode of this embodiment further includes an electrode structure, which includes a first electrode 106 and a second electrode 107. The first electrode 701 is disposed above the metal stack structure 1063 above the first mesa structure 104 and is electrically connected to the first semiconductor layer 1011 exposed by the first mesa structure 104. The second electrode 107 is disposed above the second mesa structure 105 and is electrically connected to the second semiconductor layer 1013. Specifically, the first electrode 106 includes a first contact electrode 1062 located on the first mesa structure 104 and below the metal stack structure 1063, and a first electrode layer 1061 located above the metal stack structure 1063. The second electrode 107 includes a second contact electrode 1072 located above the second semiconductor layer 1013, and a second electrode layer 1071 located above the second contact electrode 1072.

[0090] In this embodiment, the light-emitting side of the light-emitting diode is disposed on the front surface 110 of the semiconductor light-emitting stack 101 where the electrode structure is also located. Therefore, both the first electrode layer 1061 and the second electrode layer 1071 are made of a transparent conductive material to ensure light emission on the light-emitting side. Optionally, the transparent layer conductive material is ITO. The materials of the first contact electrode 1062 and the second contact electrode 1072 can be one of gold, germanium, and nickel. The selection of the above contact electrode materials can ensure that the second contact electrode 7022 has a good bonding force with the first metal layer 231 of the metal stack structure 7023.

[0091] Optionally, referring to Figure 1, the second electrode layer 1071 is formed above the second mesa structure 105 and extends to cover the sidewall of the second mesa structure 105 on the side away from the first mesa structure 104. The covering height of the second electrode layer 1071 on the above-mentioned sidewall is 1 / 3 to 1 / 2 of the sidewall height of the semiconductor light-emitting stack 101. The first electrode layer 1061 covers the metal stack structure 1063 and the first contact electrode 1062 and extends to cover the sidewall of the first mesa structure 104 on the side away from the second mesa structure 105. The first electrode layer 1061 can completely cover the sidewall of the first mesa structure 104, or can extend from the sidewall of the first mesa structure 104 to cover the sidewall of the U-shaped layer 103, but the end of the first electrode layer 1061 does not exceed the interface between the U-shaped layer 103 and the conductive layer 102 to ensure that the conductive layer will not be connected to the subsequently formed electrode layer. The settings of the first electrode layer 7011 and the second electrode layer 7021 can meet the different requirements of the backend customers, such as being applied to the circuit connection of subsequent packaging to improve the yield of the circuit design after transfer.

[0092] Optionally, a passivation layer 108 is further provided on the sidewalls (the two sidewalls away from the first mesa structure 104 and close to the first mesa structure 104) and the upper surface of the second mesa structure 105. The second electrode layer 1071 is formed on the passivation layer 108. The passivation layer 108 forms an opening at the second contact electrode 1072 so that the second electrode layer 1071 is connected to the second contact electrode 1072. Optionally, the passivation layer 108 can be any one or a combination of SiO2, SiN x and SiON. In this embodiment, the material of the passivation layer 108 is a SiO2 layer, and the thickness is between For example, The setting of the passivation layer 108 on the one hand is conducive to protecting the semiconductor light-emitting stack 100 from being damaged or polluted by external water vapor, impurities and solutions during the transfer process, and on the other hand ensures the insulation between the second electrode 107 and other structural layers of the semiconductor light-emitting stack 101.

[0093] Refer to again Figure 1 , the metal stack structure 1063 is disposed above the first mesa structure 104 and / or the second mesa structure 105. In this embodiment, in order to avoid the absorption of the light emitted by the epitaxial layer by the metal stack structure 1063, it is preferably to dispose the metal stack structure 1063 only on the first mesa structure 104. Of course, it is also possible to dispose the metal stack structure 1063 on the second mesa structure 105 by sacrificing the light output of part of the epitaxial layer for a certain purpose. The metal stack structure 1063 is disposed above the first mesa structure 104. Refer to Figure 2, the metal stack structure 1063 includes alternately arranged first metal layer 631 and first metal layer 632. Among them, the first metal layer 632 is a magnetic metal layer, and the volume ratio of the magnetic metal layer to the light-emitting diode ranges from 0.4% to 1.2%. This magnetic metal stack structure 1063 is used to cooperate with the magnetic field or electric field in the transfer environment during subsequent chip transfer, so that it can be transferred to a fixed position under the action of magnetic force or electric force. Controlling the volume ratio of the magnetic metal layer to the light-emitting diode to range from 0.4% to 1.2% can achieve effective transfer of the chip under magnetic field or electric field.

[0094] To avoid unnecessary damage to the metal stack structure 1063 during the etching process of the subsequently formed electrode structure, which may affect the bonding between the subsequent electrode and the first mesa structure 104 and prevent the electrode from falling off. Refer to Figure 2 , in this embodiment, the layer closest to the first mesa structure 104 and the layer farthest from the first mesa structure 104 in the metal stack structure 1063 are both the first metal layer 631. Moreover, the material of the first metal layer 631 is set as an inert metal material that is not easily etched by the etching solution, so as to avoid damage to the surfaces of both the metal stack structure 1063 and the first contact electrode 1062 in contact with the first mesa structure 104, and ensure the adhesion of the electrode layer. In another example of this embodiment, refer to Figure 3 , each first metal layer 631 covers all surfaces of the magnetic metal layer below it. Since the magnetic metal layer is covered by the first metal layer 631, compared with the Figure 2 metal stack structure 1063, the first metal layer 631 protects the side surface of the magnetic metal layer and will not be corroded by the etching solution, ensuring its magnetism. Optionally, the metal layer on the side farthest from the first mesa structure 104 will first contact the etching solution. Therefore, the thickness of the metal layer on the side farthest from the first mesa structure 104 is set to be greater than the thickness of the layer closest to the first mesa structure 104 to better protect the magnetic metal layer from being corroded by the etching solution.

[0095] To improve the bonding force or adhesion between the metal stack structure 1063 and the first mesa structure 104, this embodiment sets the metal stack structure 1063 as a stacked structure to relieve the structural stress of the metal stack structure 1063 and improve the bonding force. Optionally, as Figure 2 or Figure 3As shown, the number of layers of the first metal layer 631 is between 3 and 8 layers, and the number of layers of the second metal layer 632 is one less than that of the first metal layer 631. In this embodiment, the number of layers of the first metal layer 631 is 4 layers, and the number of layers of the second metal layer 632 is 3 layers. In order to control the thickness of the metal stack structure 1063 and ensure the magnetic force of the metal stack structure 1063, the thickness of the magnetic first metal layer 632 is more than 5 times, for example, 10 times, the thickness of the first metal layer 631. In a specific example, the metal stack structure 1063 is specifically a stacked structure of the first metal layer 631 / the second metal layer 632 / the first metal layer 631 / the second metal layer 632 / the first metal layer 631 / the second metal layer 632 / the first metal layer 631. Among them, the material of the first metal layer 631 is platinum, and the material of the second metal layer 632 is nickel. The thickness of the metal stack is set to For example: Of course, the material of the first metal layer 631 can also be other inert metal materials that are resistant to etching by the etching solution, and this inert metal material needs to have good adhesion to the first mesa structure 104 or the first contact electrode 1062 formed on the first mesa structure 104. In order to achieve good metal bonding force and buffer the structural stress, the cross-sectional area of the metal stack structure 1063 gradually decreases in the direction away from the first mesa structure 104. The angle between the side wall of the metal stack structure 1063 and the plane where the surface of the first mesa structure 104 is located is between 30° and 50°, for example, 40 ± 3°. And when the angle between the side wall of the metal stack structure 1063 and the plane where the surface of the first mesa structure 104 is located is between 40 ± 3°, combined with the above thickness range setting of the metal stack structure 1063, the volume of the magnetic metal can account for 0.4 to 1.2% of the volume of the light-emitting diode.

[0096] Embodiment 2

[0097] This embodiment also provides a light-emitting diode, which includes a semiconductor light-emitting stack 101, a metal stack structure 1063 located on the front surface 110 of the semiconductor light-emitting stack 101, a conductive layer 102 located on the back surface 120 of the semiconductor light-emitting stack 101, and a U-shaped layer 103 located between the conductive layer 102 and the semiconductor light-emitting stack 101. Among them, the metal stack structure 1063 includes a magnetic metal layer. The metal stack structure 1063 with magnetism is used to cooperate with the magnetic field and electric field in the transfer environment during subsequent chip transfer. The conductive layer 102 enables the back surface 120 of the light-emitting diode to conduct electricity, and thus can be affected by the electric field force. The magnetic metal layer and the conductive layer 102 cause the front surface 110 and the back surface 120 of the light-emitting diode to be stressed simultaneously, realizing the transfer of the light-emitting diode under the action of the magnetic field force and the electric field force. At the same time, it prevents the light-emitting diode from flipping during magnetic force transfer, improving the transfer yield.

[0098] The same parts as in Embodiment 1 will not be described again. The differences are as follows: As Figure 4 shown, the light-emitting diode of this embodiment also has a substrate on the back surface 120 side of the semiconductor light-emitting stack 101, and this substrate is located on the side of the conductive layer 102 away from the semiconductor light-emitting stack 101. In this embodiment, this substrate is the growth substrate 109 of the semiconductor light-emitting stack 101, and this growth substrate can be any substrate suitable for growing the above-mentioned conductive layer 102 and semiconductor light-emitting stack 101, such as a sapphire substrate, a gallium arsenide substrate, a silicon or germanium substrate, etc. In this embodiment, a gallium arsenide substrate is preferably used.

[0099] Embodiment 3

[0100] This embodiment also provides a light-emitting diode, which includes a semiconductor light-emitting stack 101, a metal stack structure 1063 located on the front surface 110 of the semiconductor light-emitting stack 101, a conductive layer 102 located on the back surface 120 of the semiconductor light-emitting stack 101, and a U-shaped layer 103 located between the conductive layer 102 and the semiconductor light-emitting stack 101. Among them, the metal stack structure 1063 includes a magnetic metal layer. The metal stack structure 1063 with magnetism is used to cooperate with the magnetic field and electric field in the transfer environment during subsequent chip transfer. The conductive layer 102 enables the back surface 120 of the light-emitting diode to conduct electricity, and thus can be affected by the electric field force. The magnetic metal layer and the conductive layer 102 cause the front surface 110 and the back surface 120 of the light-emitting diode to be stressed simultaneously, realizing the transfer of the light-emitting diode under the action of the magnetic field force and the electric field force. At the same time, it prevents the light-emitting diode from flipping during magnetic force transfer, improving the transfer yield.

[0101] The same parts as in Embodiment 1 will not be described again. The differences are as follows: As Figure 5As shown, the light-emitting diode of this embodiment further has a bonding substrate 200 on the back surface 120 of the semiconductor light-emitting stack 101, and the bonding substrate 200 is located on one side of the back surface 120 of the semiconductor light-emitting stack 101. Specifically, as Figure 5 shown, the bonding substrate 200 is located on the side of the conductive layer 102 away from the semiconductor light-emitting stack 101. An insulating bonding layer 201 is provided between the conductive layer 102 and the bonding substrate 200, and the insulating bonding layer 201 bonds the semiconductor light-emitting stack 101 provided with the conductive layer 102 to the bonding substrate. The insulating bonding layer 201 can be, for example, a BCB glue layer, etc. Optionally, in order to increase the bonding force between the BCB glue layer and the side of the conductive layer 102, an oxide layer, such as a SiO2 layer, can also be provided between the insulating bonding layer 201 and the conductive layer 102. In an alternative embodiment, the thickness of the insulating bonding layer 201 ranges from 1 μm to 3 μm, such as 2 μm, 3 μm, etc. The thickness of the SiO2 layer ranges from For example etc.

[0102] In an alternative embodiment, in order to meet the peeling requirements of the bonding substrate 200 and the insulating bonding layer 201, an insulating dissociation layer 202 can also be provided between the insulating bonding layer 201 and the bonding substrate 200. Optionally, the above-mentioned bonding substrate 200 can be a substrate with a certain strength and easy to peel, so as to be able to support the semiconductor light-emitting stack 101 temporarily bonded thereto, and at the same time be easy to peel from the semiconductor light-emitting stack 101 during the subsequent transfer process. For example, a glass substrate, a sapphire substrate, a silicon substrate, etc. The insulating dissociation layer 202 can bond well with the bonding layer 200 on the one hand, and is easy to peel the bonding substrate 200 subsequently on the other hand, while protecting the integrity of the structures of the insulating bonding layer 201 and the conductive layer 102. In this embodiment, the insulating dissociation layer 202 is a SiN x layer. Its thickness ranges from For example etc.

[0103] Embodiment 4

[0104] This embodiment also provides a light-emitting diode, which includes a semiconductor light-emitting stack 101, a metal stack structure 1063 on the front surface 110 of the semiconductor light-emitting stack 101, a conductive layer 102 on the back surface 120 of the semiconductor light-emitting stack 101, and a U-shaped layer between the conductive layer 102 and the semiconductor light-emitting stack 101. Among them, the metal stack structure 1063 includes a magnetic metal layer. The metal stack structure 1063 with magnetism is used to cooperate with the magnetic field and electric field in the transfer environment during subsequent chip transfer. The conductive layer 102 enables the back surface 120 of the light-emitting diode to conduct electricity, and thus can be affected by the electric force. The magnetic metal layer and the conductive layer 102 make the front surface 110 and the back surface 120 of the light-emitting diode be stressed simultaneously, realizing the transfer of the light-emitting diode under the action of the magnetic force and the electric force. At the same time, it prevents the light-emitting diode from flipping during magnetic transfer, improving the transfer yield.

[0105] The same parts as those in Embodiment 1 will not be described in detail. The differences are as follows: In this embodiment, referring to Figure 6 and Figure 7 , the first mesa structure 104 is circumferentially arranged around the second mesa structure 105, and the metal stack structure 1063 extends along the surface of the first mesa structure 104, also forming an annular structure. The setting of this annular structure makes the magnetic metal material evenly distributed on the surface of the first mesa structure 104, which is beneficial to improving the stability of the light-emitting diode during the transfer process. In this embodiment, the passivation layer 108 covers the surface of the second mesa structure 105 and its circumferential sidewalls.

[0106] Embodiment Five

[0107] This embodiment provides a semiconductor structure, as shown in Figure 8 , the semiconductor structure 800 includes: a carrier substrate 801 and a plurality of light-emitting units 803 located on the carrier substrate 801. Specifically, a plurality of carrier portions 802 are provided on the carrier substrate 801, and the carrier portion 802 can be, for example, a concave structure provided on the carrier substrate 801. The above light-emitting units 803 can be light-emitting diodes provided in any one of Embodiments 1 to 4 transferred magnetically. And when the light-emitting diode is the light-emitting diode in Embodiment 3, the bonding substrate 200 therein can be peeled off from the insulating dissociation layer 202 of the light-emitting diode during transfer. The above light-emitting diodes are respectively carried on the carrier portions 802, and the back surface 120 side of the semiconductor light-emitting stack 100 of the light-emitting diode faces the carrier portion 802.

[0108] Embodiment Six

[0109] This embodiment provides a display device, referring to Figure 9, the display device 900 includes a packaging substrate 901 and at least one light-emitting diode 903 disposed on the packaging substrate 901. The light-emitting diode 903 may include the light-emitting diode provided in any one of Embodiments 1 to 4 that can be magnetically transferred. And when the light-emitting diode 903 is the light-emitting diode in Embodiment 3, the bonding substrate 200 therein can be peeled off from the insulating dissociation layer 202 of the light-emitting diode during transfer. The light-emitting diode is electrically connected to the packaging substrate 901 through a first electrode 106 and a second electrode 107.

[0110] Optionally, the light-emitting diode 903 is fixed to the packaging substrate 901 from the back surface 120 side, and the front surface 110 side is the light-emitting side. A reflection structure 902 is further disposed between the light-emitting diode 903 and the packaging substrate 901. The light emitted from the light-emitting diode 903 from the back surface 120 side is reflected by the reflection structure 902 and then emitted from the front surface side, realizing front surface light emission.

[0111] The above embodiments are only illustrative of the principles and effects of the present invention and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A light emitting diode, characterized in that, At least including: A semiconductor light-emitting stack, including a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type stacked in sequence. The side of the second semiconductor layer away from the active layer is the front surface of the semiconductor light-emitting stack, and the side of the first semiconductor layer away from the active layer is the back surface of the semiconductor light-emitting stack; A metal stack structure, disposed on the front surface of the semiconductor light-emitting stack, and the metal stack structure includes a magnetic metal layer; A conductive layer, located on the back surface of the semiconductor light-emitting stack, and the conductive layer is a semiconductor layer of the second conductivity type; A U-shaped layer, located between the conductive layer and the first semiconductor layer.

2. The light-emitting diode according to claim 1, wherein, The conductive layer is an AlGaInP layer doped with Mg, C, or Zn.

3. The light emitting diode according to claim 1 or 2, characterized in that, The P-type doping concentration of the conductive layer is between 2E18 atoms / cm 3 ~4.5E18 atoms / cm 3 .

4. The light-emitting diode according to claim 1, wherein, The first semiconductor layer is an AlGaInP layer doped with Si.

5. The light-emitting diode according to claim 1, wherein, The thickness of the conductive layer is 20% - 25% of the thickness of the first semiconductor layer.

6. The light-emitting diode according to claim 1 or 5, characterized in that The thickness of the conductive layer is between 0.5 μm and 1.5 μm.

7. The light-emitting diode according to claim 1, characterized in that, The U-shaped layer is an undoped AlGaInP layer.

8. The light-emitting diode according to claim 1 or 7, characterized in that, The thickness of the U-shaped layer is between 0.5 μm and 1.5 μm.

9. The light-emitting diode according to claim 1, wherein The side wall of the light-emitting diode is an inclined side wall, and the angle between the side wall and the plane where the back surface is located is between 70° and 90°.

10. The light-emitting diode according to claim 1, wherein, Etch the second semiconductor layer, the active layer, and a part of the first semiconductor layer sequentially downward from a part of the surface of the front surface. The exposed first semiconductor layer after etching forms a first mesa structure; The unetched second semiconductor layer, active layer, and the corresponding part of the first semiconductor layer form a second mesa structure, and the metal stack structure is disposed above the first mesa structure.

11. The light emitting diode according to claim 10, characterized in that, The metal stack structure includes a first metal layer and a second metal layer arranged alternately; wherein, the first metal layer is an inert metal layer, and the second metal layer is a magnetic metal layer; the layers closest to the first mesa structure and farthest from the first mesa structure in the metal stack structure are both the first metal layer, and the thickness of the layer closest to the first mesa structure is less than the thickness of the layer farthest from the first mesa structure.

12. The light-emitting diode according to claim 10, wherein The cross-sectional area of the metal stack structure gradually decreases in the direction away from the first mesa structure, and the angle between the inner side wall of the metal stack structure and the surface of the first mesa structure is between 30° and 50°.

13. The light-emitting diode according to claim 1, 10, 11 or 12, characterized in that, The proportion of the volume of the magnetic metal layer in the volume of the light-emitting diode is between 0.4% and 1.2%.

14. The light emitting diode according to claim 10, wherein, The height difference between the first mesa structure and the second mesa structure occupies 1 / 3 - 1 / 2 of the height of the semiconductor light-emitting stack.

15. The light-emitting diode according to claim 10, characterized in that, The height difference between the first mesa structure and the second mesa structure is between 2.5 μm and 2.8 μm, and the height of the semiconductor light-emitting stack is between 3 μm and 6 μm.

16. The light emitting diode according to claim 10, characterized in that, The light-emitting diode further includes: A first electrode layer, disposed on the first mesa, and forming an electrical connection with the first semiconductor layer; A second electrode layer, disposed on the metal stack structure of the second mesa structure, and forming an electrical connection with the second semiconductor layer.

17. The light emitting diode according to claim 16, wherein, The materials of the first electrode layer and the second electrode layer are transparent conductive materials.

18. The light-emitting diode according to claim 16, wherein, The first electrode layer further extends and covers the sidewall of the first mesa structure on the side away from the second mesa structure, and the end of the first electrode layer on the sidewall does not exceed the interface between the U-shaped layer and the first semiconductor layer; The second electrode layer extends from the surface of the second mesa structure and covers the sidewall of the second mesa structure, and the second electrode layer is insulated from the conductive layer.

19. The light-emitting diode according to claim 18, characterized in that, A passivation layer is further provided on the surface and sidewall of the second mesa structure, and the second electrode layer is formed on the passivation layer.

20. The light-emitting diode according to claim 1, wherein It further includes a substrate, and the substrate is a growth substrate for the semiconductor light-emitting stack; or the substrate is a bonding substrate, and there is an insulating bonding layer between the bonding substrate and the conductive layer.

21. A semiconductor structure, characterized in that, It includes: A carrier substrate provided with a plurality of carrier portions; A plurality of light-emitting units are respectively carried on the carrier portions; Wherein The light-emitting unit includes the light-emitting diode according to any one of claims 1 to 20 transferred by magnetism, and the back side of the semiconductor light-emitting stack of the light-emitting diode faces the carrier portion.

22. A display device, characterized in that, It includes a packaging substrate and at least one light-emitting diode provided on the packaging substrate, and the light-emitting diode includes the light-emitting diode according to any one of claims 1 to 20 transferred by magnetism.

23. The display device according to claim 22, wherein The light-emitting diode is fixed to the packaging substrate from the back side, the front side is the light-emitting side, and a reflection structure is further provided between the light-emitting diode and the packaging substrate.

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