Micro-LED chip with laminated layers

Abstract

According to the Micro-LED chip provided by the invention, electrical interconnection is formed through the P-type semiconductor layers of at least two adjacent light-emitting structures, and the refractive index difference between the two P-type semiconductor layers is smaller than the refractive index between the P-type semiconductor layer and the N-type semiconductor layer, so that the photon reflection phenomenon can be well reduced, the loss of photons in the LED chip is reduced, and the light-emitting efficiency is improved. The luminous efficiency of the LED is improved, so that more light output is generated; meanwhile, the P-type semiconductor layers of the two adjacent light-emitting structures are electrically connected to replace the isolation between the upper light-emitting structure and the lower light-emitting structure, so that the influence of a chip heat effect caused by poor heat dissipation of an insulating material is eliminated.

Description

Technical Field

[0001] The present invention relates to the field of light emitting diodes, and in particular to a Micro-LED chip with stacked layers. Background Art

[0002] Light Emitting Diode (LED) is a semiconductor electronic component that can emit light. LED has the advantages of high efficiency, long life, small size, low power consumption, etc. It can be used in indoor and outdoor white light lighting, screen display, backlight and other fields.

[0003] Among them, Micro-LED is prepared by bonding the blue, green and red LED chips together. The full-color Micro-LED made in this way can be better mixed together, and because the three-color chips are stacked vertically, relative to traditional displays, for screens with the same resolution, the chip size used in its stacked structure can be three times larger. The large chip size not only improves the product yield, but also avoids the size effect to a certain extent for Micro-LED (the smaller the device, the lower the external quantum efficiency). Therefore, the stacked structure plays an important role in promoting the full-colorization of Micro-LED.

[0004] In the process of preparing Micro-LED, in order to achieve high-resolution display, it is necessary to continuously reduce the size of the chip. In this process, the performance of Micro-LED chips drops sharply, the difficulty of chip preparation increases sharply, and the uniformity of light emission will be greatly affected. Current display panels usually arrange blue (B), green (G), and red (R) sub-pixels horizontally to achieve full color, and each pixel requires three sub-pixels. This low geometric fill factor itself limits the enhancement of display panel resolution. By stacking multiple Micro-LED layers, higher pixel density can be achieved in a limited space, and only one pixel is needed to produce full color, thereby improving the resolution and image quality of the display. Compared with horizontally arranged RGB Micro-LED, stacked Micro-LED can reduce the connection between each individual Micro-LED pixel, but because the number of electrodes in the stacked structure is large and the position is close, a complex driving circuit is required for current introduction design to achieve precise control and adjustment of pixels of different colors in order to achieve accurate color reproduction.

[0005] In view of this, the inventor specially designed a Micro-LED chip with stacked layers, and this case was thus generated. Summary of the invention

[0006] The object of the present invention is to provide a stacked Micro-LED chip to simplify the electrode arrangement and connection cost of the stacked Micro-LED chip.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A Micro-LED chip with a stacked layer, comprising:

[0009] A stacked structure, the stacked structure comprising a plurality of light-emitting structures stacked in sequence; wherein each of the light-emitting structures comprises an N-type semiconductor layer, an active layer and a P-type semiconductor layer, and the P-type semiconductor layers of at least two adjacent light-emitting structures are electrically interconnected;

[0010] An electrode group, the electrode group comprising a plurality of first polarity electrodes and at least one second polarity interconnected electrode embedded in the laminated structure through a through hole;

[0011] Wherein, the second polarity interconnection electrode is electrically connected to the P-type semiconductor layer of each of the light-emitting structures, and the surface of the N-type semiconductor layer of each of the light-emitting structures is respectively provided with the first polarity electrode;

[0012] Alternatively, the second polarity interconnecting electrode is electrically connected to the N-type semiconductor layer of each of the light emitting structures, and the surface of the P-type semiconductor layer of each of the light emitting structures is respectively provided with the first polarity electrode.

[0013] Preferably, the P-type semiconductor layers of the two adjacent light emitting structures are electrically interconnected via a transparent bonding layer.

[0014] Preferably, the transparent bonding layer includes a transparent conductive layer, such as a material layer of ITO, IZO, etc.

[0015] Preferably, the stacked structure includes a first light emitting structure, a second light emitting structure and a third light emitting structure which are sequentially stacked in a stepped manner.

[0016] Preferably, the Micro-LED chip comprises a front-mounted structure LED chip, the N-type semiconductor layers of the first light-emitting structure and the second light-emitting structure are electrically interconnected, and the P-type semiconductor layers of the second light-emitting structure and the third light-emitting structure are electrically interconnected; and a reflector is provided on a surface of the first light-emitting structure facing away from the second light-emitting structure, then:

[0017] The second polarity interconnecting electrode is connected to the N-type semiconductor layer of the first light-emitting structure or the second light-emitting structure through a via hole from the surface of the third light-emitting structure, and each of the first polarity electrodes is in contact with the P-type semiconductor layer of the first light-emitting structure, the second light-emitting structure and the third light-emitting structure by being stacked on a step surface.

[0018] Preferably, there are a plurality of second polarity interconnecting electrodes, and a transparent conductive layer is provided on the surface of the third light emitting structure to electrically connect the second polarity interconnecting electrodes.

[0019] Preferably, the first light emitting structure, the second light emitting structure and the third light emitting structure are configured to emit red light, green light and blue light, respectively.

[0020] Preferably, the first light emitting structure, the second light emitting structure and the third light emitting structure are configured to emit red light, blue light and green light, respectively.

[0021] Preferably, the Micro-LED chip comprises a flip-chip structure LED chip, the N-type semiconductor layers of the first light-emitting structure and the second light-emitting structure are electrically interconnected, and the P-type semiconductor layers of the second light-emitting structure and the third light-emitting structure are electrically interconnected; and a reflector is provided on a surface of the first light-emitting structure facing away from the second light-emitting structure, then:

[0022] The second polarity interconnection electrode is connected to the P-type semiconductor layer of the second light-emitting structure or the third light-emitting structure through a via hole from the surface of the reflector, and each of the first polarity electrodes is in contact with the N-type semiconductor layer of the first light-emitting structure, the second light-emitting structure and the third light-emitting structure by being stacked on a step surface.

[0023] Preferably, there are a plurality of via holes, and the second polarity interconnection electrode is embedded in each of the via holes in a manner of being stacked on the reflector to form a connection with the P-type semiconductor layer of the second light-emitting structure or the third light-emitting structure.

[0024] Preferably, the first light emitting structure, the second light emitting structure and the third light emitting structure are configured to emit red light, green light and blue light, respectively.

[0025] Preferably, the first light emitting structure, the second light emitting structure and the third light emitting structure are configured to emit red light, blue light and green light, respectively.

[0026] Preferably, the stacked structure includes a first light-emitting structure and a second light-emitting structure which are sequentially stacked in a stepped manner;

[0027] The P-type semiconductor layers of the first light emitting structure and the second light emitting structure are electrically interconnected, and a reflector is provided on a surface of the first light emitting structure facing away from the second light emitting structure;

[0028] The second polarity interconnection electrode is connected to the P-type semiconductor layer of the first light-emitting structure or the second light-emitting structure through a via from the surface of the reflector; there are two first polarity electrodes, one of which is in contact with the N-type semiconductor layer of the first light-emitting structure by being stacked on a step surface, and the other first polarity electrode is arranged on the surface of the second light-emitting structure to form contact with the N-type semiconductor layer of the second light-emitting structure.

[0029] Preferably, the first polarity electrode disposed on the surface of the second light emitting structure is disposed on an edge of the second light emitting structure.

[0030] Preferably, the first light emitting structure and the second light emitting structure are configured to emit green light and blue light, respectively.

[0031] Through the above technical solution, it can be known that the Micro-LED chip with stacking provided by the present invention includes a stacking structure, and the stacking structure includes a plurality of light-emitting structures stacked in sequence; wherein each of the light-emitting structures includes an N-type semiconductor layer, an active layer and a P-type semiconductor layer, and the P-type semiconductor layers of at least two adjacent light-emitting structures are electrically interconnected; an electrode group, the electrode group includes a plurality of first polarity electrodes and at least one second polarity interconnection electrode embedded in the stacking structure through a through hole; wherein the second polarity interconnection electrode is electrically connected to the P-type semiconductor layer of each of the light-emitting structures, and the surface of the N-type semiconductor layer of each of the light-emitting structures is respectively provided with the first polarity electrode, or, the second polarity interconnection electrode is electrically connected to the N-type semiconductor layer of each of the light-emitting structures, and the surface of the P-type semiconductor layer of each of the light-emitting structures is respectively provided with the first polarity electrode. By forming an electrical interconnection through the P-type semiconductor layers of at least two adjacent light-emitting structures, and utilizing the fact that the refractive index difference between the two P-type semiconductor layers is smaller than the refractive index between the P-type semiconductor layer and the N-type semiconductor layer, the photon reflection phenomenon can be well reduced, the photon loss inside the LED chip can be reduced, and the luminous efficiency of the LED can be improved, thereby generating more light output; at the same time, the electrical interconnection formed by the P-type semiconductor layers of the two adjacent light-emitting structures replaces the isolation setting between the upper and lower light-emitting structures, eliminating the influence of the chip thermal effect caused by the poor heat dissipation of the insulating material.

[0032] In addition, based on the above-mentioned configuration, the second polarity interconnection electrode is embedded in the stacked structure through a through hole to connect the P-type semiconductor layer of each of the light-emitting structures or to connect the N-type semiconductor layer of each of the light-emitting structures; and by utilizing a stepped stacking technology, all of the N-type semiconductor layers or all of the P-type semiconductor layers each have an electrode access area on the corresponding step surface to achieve a stacked common N-electrode or common P-electrode design, thereby simplifying the electrode setting and connectivity cost of the stacked Micro-LED chip and saving wafer loss area while achieving independent driving of each of the light-emitting structures.

[0033] Secondly, a transparent bonding layer (such as a transparent conductive layer such as ITO\IZO) is provided on the joint surface of two adjacent light-emitting structures, thereby achieving uniform distribution of current. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0035] Figure 1 A schematic diagram of the structure of a stacked Micro-LED chip provided in Example 1 of the present invention;

[0036] Figure 2 A schematic diagram of the structure of the red light emitting structure provided in Embodiment 1 and Embodiment 2 of the present invention;

[0037] Figure 3 A schematic diagram of the structure of the blue light emitting structure provided in Embodiment 1, Embodiment 2 and Embodiment 3 of the present invention;

[0038] Figure 4 It is a schematic structural diagram of the green light emitting structure of Embodiment 1, Embodiment 2 and Embodiment 3 of the present invention;

[0039] Figure 5 A schematic diagram of the structure of a stacked Micro-LED chip provided in Example 2 of the present invention;

[0040] Figure 6 A schematic diagram of the structure of a stacked Micro-LED chip provided in Example 3 of the present invention;

[0041] Explanation of symbols in the figure:

[0042] 1. A first light-emitting structure;

[0043] 2. A second light emitting structure;

[0044] 3. A third light-emitting structure;

[0045] 1.1, 2.1, 3.1: substrate;

[0046] 1.2, corrosion stop layer, 2.2, 3.2: buffer layer,;

[0047] 1.3, 2.3, 3.3: N-type semiconductor layer;

[0048] 1.4, 2.4, 3.4: active layer;

[0049] 1.5, 2.5, 3.5: P-type semiconductor layer;

[0050] 4. Adhesive layer;

[0051] 5. Transparent bonding layer;

[0052] 6. Transparent conductive layer;

[0053] 7. Second polarity interconnection electrode

[0054] 8.1, 8.2, 8.3: First polarity electrodes. DETAILED DESCRIPTION

[0055] To make the content of the present invention clearer, the content of the present invention is further described below in conjunction with the accompanying drawings. The present invention is not limited to this specific embodiment. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0056] Example 1

[0057] like Figure 1 As shown, a stacked Micro-LED chip includes:

[0058] A stacked structure, the stacked structure comprising a plurality of light-emitting structures stacked in sequence; wherein each of the light-emitting structures comprises an N-type semiconductor layer (1.3, 2.3, 3.3), an active layer (1.4, 2.4, 3.4) and a P-type semiconductor layer (1.5, 2.5, 3.5), and the P-type semiconductor layers of at least two adjacent light-emitting structures are electrically interconnected;

[0059] An electrode group, the electrode group comprising a plurality of first polarity electrodes (8.1, 8.2, 8.3) and at least one second polarity interconnected electrode 7 embedded in the laminate structure through a through hole;

[0060] The second polarity interconnection electrode 7 is electrically connected to the N-type semiconductor layer of each of the light-emitting structures, and the surface of the P-type semiconductor layer of each of the light-emitting structures is provided with the first polarity electrodes (8.1, 8.2, 8.3) respectively.

[0061] Furthermore, in order to achieve a better uniform distribution of current, the first polarity electrodes (8.1, 8.2, 8.3) can be simultaneously disposed on both sides of the stacked Micro-LED chip.

[0062] Furthermore, the P-type semiconductor layers of the two adjacent light-emitting structures are electrically interconnected via a transparent bonding layer 5 .

[0063] Furthermore, the transparent bonding layer 5 includes a transparent conductive layer, such as a material layer of ITO, IZO, etc.

[0064] Furthermore, the stacked structure includes a first light emitting structure 1, a second light emitting structure 2 and a third light emitting structure 3 which are sequentially stacked in a stepped manner.

[0065] Based on the above, in an embodiment of the present invention, the Micro-LED chip includes a front-mounted structure LED chip, the N-type semiconductor layers of the first light-emitting structure 1 and the second light-emitting structure 2 are electrically interconnected, and the P-type semiconductor layers of the second light-emitting structure 2 and the third light-emitting structure 3 are electrically interconnected; and a reflector is provided on a surface of the first light-emitting structure 1 facing away from the second light-emitting structure 2, then:

[0066] The second polarity interconnection electrode 7 is connected to the N-type semiconductor layer of the first light-emitting structure 1 or the second light-emitting structure 2 through a via hole from the surface of the third light-emitting structure 3, and each of the first polarity electrodes (8.1, 8.2, 8.3) is stacked on the step surface to form contact with the P-type semiconductor layer of the first light-emitting structure 1, the second light-emitting structure 2 and the third light-emitting structure 3. It should be noted that an insulating layer is provided on the side wall of the via hole to prevent the second polarity interconnection electrode 7 from contacting the P-type semiconductor layer of the light-emitting structure and causing a short circuit.

[0067] In one embodiment of the present invention, there are a plurality of second polarity interconnection electrodes 7 , and a transparent conductive layer 6 is provided on the surface of the third light emitting structure 3 to electrically connect the second polarity interconnection electrodes 7 .

[0068] In one embodiment of the present invention, the reflecting mirror comprises an Ag mirror.

[0069] In one embodiment of the present invention, a first reflective structure is provided on a surface of one side of the first light-emitting structure 1 close to the second light-emitting structure 2; and the first reflective structure is used to transmit light of the first light-emitting structure 1 and reflect light of the second light-emitting structure 2 and the third light-emitting structure 3.

[0070] In one embodiment of the present invention, the first light emitting structure 1 , the second light emitting structure 2 and the third light emitting structure 3 are respectively configured as a red light emitting structure emitting red light, a red light emitting structure emitting green light and a red light emitting structure emitting blue light.

[0071] In one embodiment of the present invention, the first light emitting structure 1 , the second light emitting structure 2 and the third light emitting structure 3 are respectively configured as a red light emitting structure emitting red light, a blue light emitting structure and a green light emitting structure.

[0072] The red light emitting structure includes a gallium arsenide-based light emitting structure, which uses laser stripping to remove the substrate and other process material layers of the red light epitaxial wafer, and deposits SiO2 and TiO2 layers on the surface of the N-type semiconductor layer by plasma chemical vapor deposition (PECVD) or atomic layer deposition (ALD) to form a DBR reflection as a first reflection structure, but this application is not limited to this. Figure 2 As shown, the N-type semiconductor layer 1.3 of the red light emitting structure can be but not limited to an N-type AlGaInP layer, and correspondingly, the P-type semiconductor layer 1.5 can be but not limited to a P-type AlGaInP layer, and the substrate 1.1 includes but is not limited to a gallium arsenide substrate; and an etching stop layer 1.2 is also provided between the gallium arsenide substrate and the N-type AlGaInP layer as a process material layer, and a window layer may also be provided on the surface of the P-type semiconductor layer 1.5, but the present application does not impose any limitation on this.

[0073] The blue light emitting structure / green light emitting structure includes a gallium nitride-based light emitting structure, laser stripping is used to remove the sapphire substrate and other process material layers of the blue light epitaxial wafer, and an IZO layer / ITO layer is deposited on the surface of the P-type semiconductor layer by physical vapor deposition (PVD) and other methods as a transparent bonding layer 5, but this application is not limited to this. Figure 3 Or as shown in 4, the N-type semiconductor layer (2.3, 3.3) of the blue light emitting structure / green light emitting structure can be but not limited to an N-type gallium nitride layer, and correspondingly, the P-type semiconductor layer (2.5, 3.5) can be but not limited to a P-type gallium nitride layer, and the substrate (2.1, 3.1) includes but is not limited to a sapphire substrate; at the same time, a buffer layer (2.2, 3.2) can also be provided between the substrate (2.1, 3.1) and the N-type semiconductor layer (2.3, 3.3) as a process material layer.

[0074] Among them, the red light emitting structure is bonded to the blue light emitting structure / green light emitting structure through an adhesive layer 4, and the adhesive layer 4 includes a NOA series adhesive; the blue light emitting structure and the green light emitting structure are in contact through a transparent bonding layer 5, such as transparent conductive materials such as ITO and IZO.

[0075] It can be known from the above technical scheme that the Micro-LED chip with stacking provided by the present invention includes a stacking structure, wherein the stacking structure includes a plurality of light-emitting structures stacked in sequence; wherein each of the light-emitting structures includes an N-type semiconductor layer, an active layer and a P-type semiconductor layer, and the P-type semiconductor layers of at least two adjacent light-emitting structures are electrically interconnected; an electrode group, wherein the electrode group includes a plurality of first polarity electrodes (8.1, 8.2, 8.3) and at least one second polarity interconnection electrode 7 embedded in the stacking structure through a through hole; wherein the second polarity interconnection electrode 7 is electrically connected to the N-type semiconductor layer of each of the light-emitting structures, and the surface of the P-type semiconductor layer of each of the light-emitting structures is respectively provided with the first polarity electrode (8.1, 8.2, 8.3). By forming an electrical interconnection through the P-type semiconductor layers of at least two adjacent light-emitting structures, and utilizing the fact that the refractive index difference between the two P-type semiconductor layers is smaller than the refractive index between the P-type semiconductor layer and the N-type semiconductor layer, the photon reflection phenomenon can be well reduced, the photon loss inside the LED chip can be reduced, and the luminous efficiency of the LED can be improved, thereby generating more light output; at the same time, the electrical interconnection formed by the P-type semiconductor layers of the two adjacent light-emitting structures replaces the isolation setting between the upper and lower light-emitting structures, eliminating the influence of the chip thermal effect caused by the poor heat dissipation of the insulating material.

[0076] In addition, based on the above-mentioned configuration, the second polarity interconnection electrode 7 is embedded in the stacked structure through a through hole to connect the N-type semiconductor layers of each of the light-emitting structures; and by utilizing a stepped stacking technology, all of the P-type semiconductor layers have electrode access areas on the corresponding step surfaces to achieve a stacked common N-electrode design, thereby simplifying the electrode settings and connectivity costs of the stacked Micro-LED chip and saving wafer loss area while achieving independent driving of each of the light-emitting structures.

[0077] Secondly, a transparent conductive layer is provided on the joint surface of two adjacent light-emitting structures, thereby achieving uniform distribution of current.

[0078] Example 2

[0079] like Figure 5 As shown, a stacked Micro-LED chip includes:

[0080] A stacked structure, the stacked structure comprising a plurality of light-emitting structures stacked in sequence; wherein each of the light-emitting structures comprises an N-type semiconductor layer (1.3, 2.3, 3.3), an active layer (1.4, 2.4, 3.4) and a P-type semiconductor layer (1.5, 2.5, 3.5), and the P-type semiconductor layers of at least two adjacent light-emitting structures are electrically interconnected;

[0081] An electrode group, the electrode group comprising a plurality of first polarity electrodes (8.1, 8.2, 8.3) and at least one second polarity interconnected electrode 7 embedded in the laminate structure through a through hole;

[0082] The second polarity interconnection electrode 7 is electrically connected to the P-type semiconductor layer of each of the light-emitting structures, and the surface of the N-type semiconductor layer of each of the light-emitting structures is provided with the first polarity electrodes (8.1, 8.2, 8.3) respectively.

[0083] Furthermore, in order to achieve a better uniform distribution of current, the first polarity electrodes (8.1, 8.2, 8.3) can be simultaneously disposed on both sides of the stacked Micro-LED chip.

[0084] Furthermore, the P-type semiconductor layers of the two adjacent light-emitting structures are electrically interconnected via a transparent bonding layer 5 .

[0085] Further, the transparent bonding layer 5 includes a transparent conductive layer, such as a material layer of ITO, IZO, etc. Further, the stacked structure includes a first light emitting structure 1, a second light emitting structure 2 and a third light emitting structure 3 which are stacked in a stepped manner.

[0086] Based on the above, in an embodiment of the present invention, the Micro-LED chip includes a flip-chip structure LED chip, the N-type semiconductor layers of the first light-emitting structure 1 and the second light-emitting structure 2 are electrically interconnected, and the P-type semiconductor layers of the second light-emitting structure 2 and the third light-emitting structure 3 are electrically interconnected; and a reflector is provided on a surface of the first light-emitting structure 1 facing away from the second light-emitting structure 2, then:

[0087] The second polarity interconnection electrode 7 is connected to the P-type semiconductor layer of the second light-emitting structure 2 or the third light-emitting structure 3 through a via hole from the surface of the reflector, and each of the first polarity electrodes (8.1, 8.2, 8.3) is stacked on the step surface to form contact with the N-type semiconductor layer of the first light-emitting structure 1, the second light-emitting structure 2 and the third light-emitting structure 3. It should be noted that an insulating layer is provided on the side wall of the via hole to prevent the second polarity interconnection electrode 7 from contacting the N-type semiconductor layer of the light-emitting structure and causing a short circuit.

[0088] In one embodiment of the present invention, there are multiple via holes, and the second polarity interconnection electrode 7 is embedded in each via hole in a manner of being stacked on the reflector to form a connection with the P-type semiconductor layer of the second light-emitting structure 2 or the P-type semiconductor layer of the third light-emitting structure 3 .

[0089] In one embodiment of the present invention, a first reflective structure is provided on a surface of one side of the first light-emitting structure 1 close to the second light-emitting structure 2; and the first reflective structure is used to transmit light of the first light-emitting structure 1 and reflect light of the second light-emitting structure 2 and the third light-emitting structure 3.

[0090] In one embodiment of the present invention, the reflecting mirror comprises an Ag mirror.

[0091] In one embodiment of the present invention, the first light emitting structure 1 , the second light emitting structure 2 and the third light emitting structure 3 are respectively configured as a red light emitting structure emitting red light, a red light emitting structure emitting green light and a red light emitting structure emitting blue light.

[0092] In one embodiment of the present invention, the first light emitting structure 1 , the second light emitting structure 2 and the third light emitting structure 3 are respectively configured as a red light emitting structure emitting red light, a blue light emitting structure and a green light emitting structure.

[0093] The red light emitting structure includes a gallium arsenide-based light emitting structure, which uses laser stripping to remove the substrate and other process material layers of the red light epitaxial wafer, and deposits SiO2 and TiO2 layers on the surface of the N-type semiconductor layer by plasma chemical vapor deposition (PECVD) or atomic layer deposition (ALD) to form a DBR reflection as a first reflection structure, but this application is not limited to this. Figure 2 As shown, the N-type semiconductor layer 1.3 of the red light emitting structure can be but not limited to an N-type AlGaInP layer, and correspondingly, the P-type semiconductor layer 1.5 can be but not limited to a P-type AlGaInP layer, and the substrate 1.1 includes but is not limited to a gallium arsenide substrate; and an etching stop layer 1.2 is also provided between the gallium arsenide substrate and the N-type AlGaInP layer as a process material layer, and a window layer may also be provided on the surface of the P-type semiconductor layer 1.5, but the present application does not impose any limitation on this.

[0094] The blue light emitting structure / green light emitting structure includes a gallium nitride-based light emitting structure, laser stripping is used to remove the sapphire substrate and other process material layers of the blue light epitaxial wafer, and an IZO layer / ITO layer is deposited on the surface of the P-type semiconductor layer by physical vapor deposition (PVD) and other methods as a transparent bonding layer 5, but this application is not limited to this. Figure 3 Or as shown in 4, the N-type semiconductor layer (2.3, 3.3) of the blue light emitting structure / green light emitting structure can be but not limited to an N-type gallium nitride layer, and correspondingly, the P-type semiconductor layer (2.5, 3.5) can be but not limited to a P-type gallium nitride layer, and the substrate (2.1, 3.1) includes but is not limited to a sapphire substrate; at the same time, a buffer layer (2.2, 3.2) can also be provided between the substrate (2.1, 3.1) and the N-type semiconductor layer (2.3, 3.3) as a process material layer.

[0095] Among them, the red light emitting structure is bonded to the blue light emitting structure / green light emitting structure through an adhesive layer 4, and the adhesive layer 4 includes a NOA series adhesive; the blue light emitting structure and the green light emitting structure are in contact through a transparent bonding layer 5, such as transparent conductive materials such as ITO and IZO.

[0096] It can be known from the above technical scheme that the Micro-LED chip with stacking provided by the present invention includes a stacking structure, wherein the stacking structure includes a plurality of light-emitting structures stacked in sequence; wherein each of the light-emitting structures includes an N-type semiconductor layer, an active layer and a P-type semiconductor layer, and the P-type semiconductor layers of at least two adjacent light-emitting structures are electrically interconnected; an electrode group, wherein the electrode group includes a plurality of first polarity electrodes (8.1, 8.2, 8.3) and at least one second polarity interconnection electrode 7 embedded in the stacking structure through a through hole; wherein the second polarity interconnection electrode 7 is electrically connected to the P-type semiconductor layer of each of the light-emitting structures, and the surface of the N-type semiconductor layer of each of the light-emitting structures is respectively provided with the first polarity electrode (8.1, 8.2, 8.3). By forming an electrical interconnection through the P-type semiconductor layers of at least two adjacent light-emitting structures, and utilizing the fact that the refractive index difference between the two P-type semiconductor layers is smaller than the refractive index between the P-type semiconductor layer and the N-type semiconductor layer, the photon reflection phenomenon can be well reduced, the photon loss inside the LED chip can be reduced, and the luminous efficiency of the LED can be improved, thereby generating more light output; at the same time, the electrical interconnection formed by the P-type semiconductor layers of the two adjacent light-emitting structures replaces the isolation setting between the upper and lower light-emitting structures, eliminating the influence of the chip thermal effect caused by the poor heat dissipation of the insulating material.

[0097] In addition, based on the above-mentioned configuration, the second polarity interconnection electrode 7 is embedded in the stacked structure through a through hole to connect the P-type semiconductor layers of each of the light-emitting structures; and by utilizing a stepped stacking technology, all of the N-type semiconductor layers each have an electrode access area on the corresponding step surface to achieve a stacked common P-electrode design, thereby simplifying the electrode setting and connectivity cost of the stacked Micro-LED chip and saving wafer loss area while achieving independent driving of each of the light-emitting structures.

[0098] Secondly, a transparent bonding layer 5 (such as a transparent conductive layer such as ITO\IZO) is provided on the joint surface of two adjacent light-emitting structures, thereby achieving uniform distribution of current.

[0099] Example 3

[0100] A Micro-LED chip with a stacked layer, comprising:

[0101] A stacked structure, the stacked structure comprising a first light-emitting structure 1 and a second light-emitting structure 2 stacked in sequence; wherein each of the light-emitting structures comprises an N-type semiconductor layer, an active layer and a P-type semiconductor layer, and the P-type semiconductor layers of two adjacent light-emitting structures are electrically interconnected;

[0102] An electrode group, the electrode group comprising a plurality of first polarity electrodes (8.1, 8.2) and at least one second polarity interconnected electrode 7 embedded in the laminate structure through a through hole;

[0103] Wherein, the second polarity interconnecting electrode 7 is electrically connected to the P-type semiconductor layer of each of the light-emitting structures, and the surface of the N-type semiconductor layer of each of the light-emitting structures is provided with the first polarity electrodes (8.1, 8.2) respectively. It should be noted that the side wall of the via hole and the surface of the first light-emitting structure 1 facing away from the second light-emitting structure 2 are provided with an insulating layer to prevent the second polarity interconnecting electrode 7 from contacting the N-type semiconductor layer of the light-emitting structure and causing a short circuit.

[0104] Furthermore, in order to achieve a better uniform distribution of current, the first polarity electrodes (8.1, 8.2) may be provided on both sides of the stacked Micro-LED chip.

[0105] Furthermore, the P-type semiconductor layers of the two adjacent light-emitting structures are electrically interconnected via a transparent bonding layer 5 .

[0106] Furthermore, the transparent bonding layer 5 includes a transparent conductive layer, such as a material layer of ITO, IZO, etc.

[0107] Based on the above, in an embodiment of the present invention, the stacked structure includes a first light emitting structure 1 and a second light emitting structure 2 which are stacked in a stepped manner;

[0108] The P-type semiconductor layers of the first light emitting structure 1 and the second light emitting structure 2 are electrically interconnected, and a reflector is provided on a surface of the first light emitting structure 1 that is away from the second light emitting structure 2;

[0109] The second polarity interconnection electrode 7 is connected to the P-type semiconductor layer of the first light-emitting structure 1 or the second light-emitting structure 2 through a via hole from the surface of the reflector; there are two first polarity electrodes (8.1, 8.2), wherein one of the first polarity electrodes (8.1, 8.2) is in contact with the N-type semiconductor layer of the first light-emitting structure 1 by being stacked on a step surface, and the other first polarity electrode (8.1, 8.2) is arranged on the surface of the second light-emitting structure 2 and is in contact with the N-type semiconductor layer of the second light-emitting structure 2.

[0110] In one embodiment of the present invention, the reflector can be formed by disposing Ag on a surface of the second polarity interconnection electrode 7 close to the light emitting structure.

[0111] In one embodiment of the present invention, the first polarity electrodes ( 8 . 1 , 8 . 2 ) disposed on the surface of the second light emitting structure 2 are disposed on the edge of the second light emitting structure 2 .

[0112] In one embodiment of the present invention, the first light emitting structure 1 and the second light emitting structure 2 are configured as a light emitting structure emitting blue light and a light emitting structure emitting green light.

[0113] The blue light emitting structure / green light emitting structure includes a gallium nitride-based light emitting structure, laser stripping is used to remove the sapphire substrate and other process material layers of the blue light epitaxial wafer, and an IZO layer / ITO layer is deposited on the surface of the P-type semiconductor layer by physical vapor deposition (PVD) and other methods as a transparent bonding layer 5, but this application is not limited to this. Figure 3 Or as shown in 4, the N-type semiconductor layer (2.3, 3.3) of the blue light emitting structure / green light emitting structure can be but not limited to an N-type gallium nitride layer, and correspondingly, the P-type semiconductor layer (2.5, 3.5) can be but not limited to a P-type gallium nitride layer, and the substrate (2.1, 3.1) includes but is not limited to a sapphire substrate; at the same time, a buffer layer (2.2, 3.2) can also be provided between the substrate (2.1, 3.1) and the N-type semiconductor layer (2.3, 3.3) as a process material layer.

[0114] It can be known from the above technical scheme that the Micro-LED chip with stacking provided by the present invention includes a stacking structure, wherein the stacking structure includes a plurality of light-emitting structures stacked in sequence; wherein each of the light-emitting structures includes an N-type semiconductor layer, an active layer and a P-type semiconductor layer, and the P-type semiconductor layers of at least two adjacent light-emitting structures are electrically interconnected; an electrode group, wherein the electrode group includes a plurality of first polarity electrodes (8.1, 8.2) and at least one second polarity interconnection electrode 7 embedded in the stacking structure through a through hole; wherein, the second polarity interconnection electrode 7 is electrically connected to the P-type semiconductor layer of each of the light-emitting structures, and the surface of the N-type semiconductor layer of each of the light-emitting structures is respectively provided with the first polarity electrode (8.1, 8.2). By arranging the P-type semiconductor layers of two adjacent light-emitting structures to form electrical interconnection, and utilizing the fact that the refractive index difference between the two P-type semiconductor layers is smaller than the refractive index between the P-type semiconductor layer and the N-type semiconductor layer, the photon reflection phenomenon can be well reduced, the photon loss inside the LED chip can be reduced, and the luminous efficiency of the LED can be improved, thereby generating more light output; at the same time, the electrical interconnection formed by the P-type semiconductor layers of the two adjacent light-emitting structures replaces the isolation setting between the upper and lower light-emitting structures, eliminating the influence of the chip thermal effect caused by the poor heat dissipation of the insulating material.

[0115] In addition, based on the above-mentioned configuration, the second polarity interconnection electrode 7 is embedded in the stacked structure through a through hole to connect the P-type semiconductor layers of each of the light-emitting structures; and by utilizing a stepped stacking technology, all of the N-type semiconductor layers each have an electrode access area on the corresponding step surface to achieve a stacked common P-electrode design, thereby simplifying the electrode setting and connectivity cost of the stacked Micro-LED chip and saving wafer loss area while achieving independent driving of each of the light-emitting structures.

[0116] Secondly, a transparent bonding layer 5 (such as a transparent conductive layer such as ITO\IZO) is provided on the joint surface of two adjacent light-emitting structures, thereby achieving uniform distribution of current.

[0117] Transparent Bonding Layer Transparent Bonding Layer The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referenced to each other.

[0118] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the article or device including the above elements.

[0119] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A Micro-LED chip with a stack, characterized in that: include: A stacked structure, the stacked structure comprising a plurality of light-emitting structures stacked in sequence; wherein each of the light-emitting structures comprises an N-type semiconductor layer, an active layer and a P-type semiconductor layer, and the P-type semiconductor layers of at least two adjacent light-emitting structures are electrically interconnected; An electrode group, the electrode group comprising a plurality of first polarity electrodes and at least one second polarity interconnected electrode embedded in the laminated structure through a through hole; Wherein, the second polarity interconnection electrode is electrically connected to the P-type semiconductor layer of each of the light-emitting structures, and the surface of the N-type semiconductor layer of each of the light-emitting structures is respectively provided with the first polarity electrode; Alternatively, the second polarity interconnecting electrode is electrically connected to the N-type semiconductor layer of each of the light emitting structures, and the surface of the P-type semiconductor layer of each of the light emitting structures is respectively provided with the first polarity electrode.

2. The stacked Micro-LED chip according to claim 1, characterized in that: The P-type semiconductor layers of the two adjacent light emitting structures are electrically interconnected via a transparent bonding layer.

3. The stacked Micro-LED chip according to claim 1 or 2, characterized in that: The stacked structure includes a first light emitting structure, a second light emitting structure and a third light emitting structure which are sequentially stacked in a stepped manner.

4. The stacked Micro-LED chip according to claim 3, characterized in that: The Micro-LED chip includes a front-mounted structure LED chip, the N-type semiconductor layers of the first light-emitting structure and the second light-emitting structure are electrically interconnected, and the P-type semiconductor layers of the second light-emitting structure and the third light-emitting structure are electrically interconnected; and a reflector is provided on a surface of the first light-emitting structure facing away from the second light-emitting structure, then: The second polarity interconnecting electrode is connected to the N-type semiconductor layer of the first light-emitting structure or the second light-emitting structure through a via hole from the surface of the third light-emitting structure, and each of the first polarity electrodes is in contact with the P-type semiconductor layer of the first light-emitting structure, the second light-emitting structure and the third light-emitting structure by being stacked on a step surface.

5. The stacked Micro-LED chip according to claim 4, characterized in that: If there are a plurality of second polarity interconnecting electrodes, a transparent conductive layer is provided on the surface of the third light emitting structure to electrically connect the second polarity interconnecting electrodes.

6. The stacked Micro-LED chip according to claim 4, characterized in that: The first light emitting structure, the second light emitting structure, and the third light emitting structure are configured to emit red light, green light, and blue light, respectively.

7. The stacked Micro-LED chip according to claim 4, characterized in that: The first light emitting structure, the second light emitting structure, and the third light emitting structure are configured to emit red light, blue light, and green light, respectively.

8. The stacked Micro-LED chip according to claim 3, characterized in that: The Micro-LED chip includes a flip-chip LED chip, the N-type semiconductor layers of the first light-emitting structure and the second light-emitting structure are electrically interconnected, and the P-type semiconductor layers of the second light-emitting structure and the third light-emitting structure are electrically interconnected; and a reflector is provided on a surface of the first light-emitting structure facing away from the second light-emitting structure, then: The second polarity interconnection electrode is connected to the P-type semiconductor layer of the second light-emitting structure or the third light-emitting structure through a via from the surface of the reflector, and each of the first polarity electrodes is in contact with the N-type semiconductor layer of the first light-emitting structure, the second light-emitting structure and the third light-emitting structure by being stacked on a step surface.

9. The stacked Micro-LED chip according to claim 8, characterized in that: If there are a plurality of via holes, the second polarity interconnection electrode is embedded in each of the via holes in a manner of being stacked on the reflector to form a connection with the P-type semiconductor layer of the second light emitting structure or the third light emitting structure.

10. The stacked Micro-LED chip according to claim 8, characterized in that: The first light emitting structure, the second light emitting structure, and the third light emitting structure are configured to emit red light, green light, and blue light, respectively.

11. The stacked Micro-LED chip according to claim 8, characterized in that: The first light emitting structure, the second light emitting structure, and the third light emitting structure are configured to emit red light, blue light, and green light, respectively.

12. The stacked Micro-LED chip according to claim 1 or 2, characterized in that: The stacked structure includes a first light-emitting structure and a second light-emitting structure which are stacked in a stepped manner; The P-type semiconductor layers of the first light emitting structure and the second light emitting structure are electrically interconnected, and a reflector is provided on a surface of the first light emitting structure facing away from the second light emitting structure; The second polarity interconnection electrode is connected to the P-type semiconductor layer of the first light-emitting structure or the second light-emitting structure through a via from the surface of the reflector; there are two first polarity electrodes, one of which is in contact with the N-type semiconductor layer of the first light-emitting structure by being stacked on a step surface, and the other first polarity electrode is arranged on the surface of the second light-emitting structure to form contact with the N-type semiconductor layer of the second light-emitting structure.

13. The stacked Micro-LED chip according to claim 12, characterized in that: The first polarity electrode disposed on the surface of the second light emitting structure is disposed at an edge of the second light emitting structure.

14. The stacked Micro-LED chip according to claim 12, wherein: The first light emitting structure and the second light emitting structure are configured to emit green light and blue light, respectively.

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