Micro-LED chip with laminated layers

Abstract

According to the Micro-LED chip provided by the utility model, all the P-type semiconductor layers are respectively provided with the electrode access areas on the corresponding step surfaces by utilizing the step-shaped lamination technology, so that the first light-emitting structure, the second light-emitting structure and the third light-emitting structure can be independently driven, and the light-emitting efficiency of the LED chip is improved. The wafer area can be saved to the greatest extent to realize full color, and the production cost is reduced; meanwhile, the P-type semiconductor layer of the first light-emitting structure and the P-type semiconductor layer of the second light-emitting structure are bonded through an insulating bonding layer. Therefore, the phenomenon of incomplete etching caused by non-uniform bonding thickness in the process of bonding the first light-emitting structure and the second light-emitting structure by a polymer adhesive can be avoided.

Description

Technical Field

[0001] This utility model relates to the field of light-emitting diodes, and more particularly to a Micro-LED chip with stacked layers. Background Technology

[0002] A light-emitting diode (LED) is a semiconductor electronic component that emits light. LEDs have advantages such as high efficiency, long lifespan, small size, and low power consumption, and can be used in indoor and outdoor white light lighting, screen displays, backlights, and other fields.

[0003] Micro-LEDs are fabricated by bonding blue, green, and red LED chips together. This method allows for better mixing of full-color Micro-LEDs. Furthermore, because the three-color chips are stacked vertically, the chip size used in the stacked structure can be three times larger than that of traditional displays for the same resolution screen. The larger chip size not only improves the product yield but also, to some extent, avoids the size effect (the smaller the device, the lower the external quantum efficiency) for Micro-LEDs. Therefore, the stacked structure plays an important role in promoting the full-color development of Micro-LEDs.

[0004] However, in vertically stacked LED structures, despite the elimination of external optics, the optical performance remains unsatisfactory due to severe light loss from downward emission. Low light extraction remains the main bottleneck limiting the optical performance of stacked RGB LEDs. Metal coatings, such as Au and Al, are widely used as bottom reflectors for gallium nitride-based LEDs, but their opacity prevents their application in stacked structures. Furthermore, the main metals of the reflectors for red and blue-green LEDs differ; red is primarily Au, while blue-green is primarily Al. Therefore, using metal as surface reflectors cannot simultaneously meet the requirements of three-color chips. Additionally, after blue-green light enters the epitaxial layer of the red micro-LED, it is not only absorbed by the active region of the red micro-LED but also, due to its high refractive index, does not easily escape. Since the three colors are stacked together, when the blue micro-LED is lit, it illuminates the red micro-LED, causing the active region of the red micro-LED to absorb blue light and produce red light, resulting in abnormal device colors.

[0005] Meanwhile, the bonding layer needs to be etched during the manufacturing process of stacked chips. However, polymer adhesives can result in uneven bonding thickness. Furthermore, the current etching method for polymer adhesives is dry etching, which cannot guarantee that the entire adhesive surface can be completely etched. This can lead to the scrapping of chips in areas that are not completely etched.

[0006] In view of this, the inventors specifically designed a Micro-LED chip with stacked layers, which led to this invention. Utility Model Content

[0007] The purpose of this invention is to provide a stacked Micro-LED chip to solve the problems caused by low light extraction efficiency, color mixing, and incomplete etching of existing full-color Micro-LEDs.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0009] A stacked Micro-LED chip, comprising:

[0010] Substrate;

[0011] A stacked structure, comprising a first light-emitting structure, a second light-emitting structure, and a third light-emitting structure sequentially stacked on the surface of a substrate, wherein the stacked structure is in a stepped shape;

[0012] An insulating layer is disposed on the sidewall of the laminated structure;

[0013] A second reflective structure is disposed on the surface of the stacked structure;

[0014] The first light-emitting structure, the second light-emitting structure, and the third light-emitting structure respectively include an N-type semiconductor layer, an active layer, and a P-type semiconductor layer. All N-type semiconductor layers are interconnected by connecting the corresponding stepped surfaces through the electrode connection layer via the surface of the insulating layer. Each P-type semiconductor layer has an electrode access area on its respective stepped surface.

[0015] The P-type semiconductor layer of the first light-emitting structure and the P-type semiconductor layer of the second light-emitting structure are bonded together by an insulating bonding layer.

[0016] Preferably, the N-type semiconductor layer of the second light-emitting structure and the N-type semiconductor layer of the third light-emitting structure are bonded together by a metal bonding layer.

[0017] Preferably, the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure emit light of a first wavelength, a second wavelength, and a third wavelength in sequence, and the first wavelength is smaller than the second wavelength and the third wavelength, respectively.

[0018] Preferably, a first reflective structure is provided on the surface of the first light-emitting structure near the insulating bonding layer; and the first reflective structure is used to reflect light of the first wavelength and transmit light of the second wavelength and light of the third wavelength.

[0019] Preferably, the first reflective structure includes a DBR reflector, and a current spreading layer is provided on the surface of the first light-emitting structure facing the first reflective structure.

[0020] Preferably, the stacked Micro-LED chip further includes:

[0021] The first P electrode is in contact with the P-type semiconductor layer of the first light-emitting structure by being stacked on the stepped surface;

[0022] The second P electrode is in contact with the P-type semiconductor layer of the second light-emitting structure by being stacked on the stepped surface;

[0023] The third P electrode is in contact with the P-type semiconductor layer of the third light-emitting structure by being stacked on the surface of the stacked structure away from the substrate;

[0024] The N electrode is in contact with the electrode connection layer by being stacked on the stepped surface.

[0025] Preferably, the second reflective structure includes an insulating reflector, and the insulating reflector covers the stacked structure and exposes the first P electrode, the second P electrode, the third P electrode, and the N electrode respectively.

[0026] Preferably, the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure emit blue light, green light, and red light in sequence.

[0027] Preferably, the second reflective structure includes a DBR reflector.

[0028] Preferably, a current spreading layer is provided on the surface of the second light-emitting structure facing the first reflective structure.

[0029] This utility model also provides a method for fabricating a stacked Micro-LED chip, the method comprising:

[0030] S01. Provide three independently grown light-emitting structures on a substrate, namely a first light-emitting structure, a second light-emitting structure and a third light-emitting structure, each of which includes an N-type semiconductor layer, an active layer and a P-type semiconductor layer.

[0031] S02. A current spreading layer and a first reflective structure are sequentially formed on the surface of the first light-emitting structure;

[0032] S03. The surface of the second light-emitting structure is bonded to the surface of the first reflective structure obtained in step S02 through an insulating bonding layer;

[0033] S04. Remove the substrate of the second light-emitting structure to expose the N-type semiconductor layer of the second light-emitting structure;

[0034] S05. Remove the substrate of the third light-emitting structure to expose the N-type semiconductor layer of the third light-emitting structure;

[0035] S06. The N-type semiconductor layer of the third light-emitting structure is bonded to the surface of the N-type semiconductor layer of the second light-emitting structure obtained in step S04 through a metal bonding layer to obtain a stacked structure.

[0036] S07. The stacked structure is formed into a stepped shape by etching process; specifically, the stepped surface exposes part of the N-type semiconductor layer and part of the P-type semiconductor layer of the first light-emitting structure, and part of the N-type semiconductor layer and part of the P-type semiconductor layer of the second light-emitting structure respectively.

[0037] S08. An insulating layer is formed on the surface of the stacked structure, and an etching process is used to expose at least all N-type semiconductor layers corresponding to the stepped surface.

[0038] S09. Fabricate an electrode connection layer, wherein the electrode connection layer is connected to all N-type semiconductor layers corresponding to the stepped surface via the surface of the insulating layer;

[0039] S10. A second reflective structure is fabricated on the surface of the stacked structure, and an etching process is used to expose at least all the P-type semiconductor layers corresponding to the stepped surface and a portion of the surface of the stacked structure.

[0040] S11. Fabricate the first P electrode, the second P electrode, the third P electrode, and the N electrode;

[0041] The first P electrode forms contact with the P-type semiconductor layer of the first light-emitting structure by being stacked on a stepped surface;

[0042] The second P electrode forms contact with the P-type semiconductor layer of the second light-emitting structure by being stacked on the stepped surface;

[0043] The third P electrode forms contact with the P-type semiconductor layer of the third light-emitting structure by being stacked on the exposed surface of the stacked structure;

[0044] The N electrode forms contact with the electrode connection layer by being stacked on the stepped surface.

[0045] As can be seen from the above technical solution, the Micro-LED chip with stacked layers provided by this utility model includes a stacked structure, wherein the stacked structure includes a first light-emitting structure, a second light-emitting structure, and a third light-emitting structure sequentially stacked on the surface of a substrate, and the stacked structure is stepped; an insulating layer is disposed on the sidewall of the stacked structure; and a second reflective structure is disposed on the surface of the stacked structure; wherein the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure respectively include an N-type semiconductor layer, an active layer, and a P-type semiconductor layer, all of the N-type semiconductor layers are interconnected by connecting to the corresponding stepped surfaces through an electrode connection layer via the surface of the insulating layer, and all of the P-type semiconductor layers have an electrode access area on the corresponding stepped surface; the P-type semiconductor layer of the first light-emitting structure and the P-type semiconductor layer of the second light-emitting structure are bonded by an insulating bonding layer. Based on this, by utilizing a stepped stacking technique, each of the P-type semiconductor layers has an electrode access area on its respective stepped surface. This allows for independent driving of the first, second, and third light-emitting structures, while maximizing wafer area savings to achieve full-color processing and reducing production costs. Furthermore, the bonding of the P-type semiconductor layers of the first and second light-emitting structures through an insulating bonding layer avoids the incomplete etching caused by uneven bonding thickness during the bonding process of the polymer adhesive.

[0046] Secondly, by setting the first, second, and third light-emitting structures to sequentially emit light of a first wavelength, a second wavelength, and a third wavelength, respectively, with the first wavelength being smaller than the second and third wavelengths, and further, a first reflective structure is provided on the surface of the first light-emitting structure near the insulating bonding layer; the first reflective structure is used to reflect the first wavelength light and transmit the second and third wavelength light. Based on this, by using the first reflective structure in combination with the second reflective structure to reflect the light from each light-emitting structure of the stacked structure, the first wavelength light can be prevented from exciting the light of other wavelengths without blocking the second and third wavelength light from emanating from the substrate side, thus effectively solving the problem of independent control and color mixing in the stacked structure.

[0047] Next, a current spreading layer is provided on the surface of the first light-emitting structure and / or on the side of the second light-emitting structure facing the first reflective structure, thereby achieving a uniform distribution of current. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0049] Figure 1 This is a schematic diagram of the structure of a stacked Micro-LED chip provided in an embodiment of the present invention;

[0050] Figures 2 to 16 This is a schematic diagram of the structure corresponding to the steps of the method for manufacturing a stacked Micro-LED chip provided in the embodiment of this utility model;

[0051] Explanation of symbols in the diagram:

[0052] 1. First light-emitting structure;

[0053] 2. Second light-emitting structure;

[0054] 3. Third light-emitting structure;

[0055] 1.1, 2.1, 3.1: Substrate;

[0056] 1.2, 2.2: Buffer layer; 3.2: Corrosion stop layer;

[0057] 1.3, 2.3, 3.3: N-type semiconductor layers;

[0058] 1.4, 2.4, 3.4: Active layers;

[0059] 1.5, 2.5, 3.5: P-type semiconductor layer;

[0060] 4. Current spreading layer;

[0061] 5. First reflective structure;

[0062] 6. Insulating bonding layer;

[0063] 7. Metal bonding layer;

[0064] 8. Insulation layer;

[0065] 9. Electrode connection layer;

[0066] 10. Second reflection structure;

[0067] 11. N electrode;

[0068] 12. First P electrode;

[0069] 13. Second P electrode;

[0070] 14. Third P electrode. Detailed Implementation

[0071] To make the content of this utility model clearer, the following description, in conjunction with the accompanying drawings, further illustrates the present utility model. This utility model is not limited to this specific embodiment. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0072] like Figure 1 As shown, a stacked Micro-LED chip includes:

[0073] Substrate;

[0074] A stacked structure, comprising a first light-emitting structure 1, a second light-emitting structure 2, and a third light-emitting structure 3 sequentially stacked on the surface of a substrate, wherein the stacked structure is in a stepped shape;

[0075] An insulating layer 8 is disposed on the sidewall of the laminated structure;

[0076] The second reflective structure 10 is disposed on the surface of the stacked structure;

[0077] The first light-emitting structure 1, the second light-emitting structure 2, and the third light-emitting structure 3 respectively include an N-type semiconductor layer, an active layer, and a P-type semiconductor layer. All N-type semiconductor layers are interconnected by connecting the electrode connection layer 9 to the corresponding stepped surface of the insulating layer 8. All P-type semiconductor layers have an electrode access area on the corresponding stepped surface.

[0078] The P-type semiconductor layer of the first light-emitting structure 1 and the P-type semiconductor layer of the second light-emitting structure 2 are bonded together by an insulating bonding layer 6.

[0079] It should be noted that, in one embodiment of this utility model, the substrate is a transparent substrate, including but not limited to a sapphire substrate, and this application does not limit it.

[0080] In one embodiment of the present invention, the insulating bonding layer 6 includes, but is not limited to, a silicon oxide bonding layer.

[0081] In one embodiment of this invention, the N-type semiconductor layer of the second light-emitting structure 2 and the N-type semiconductor layer of the third light-emitting structure 3 are bonded together by a metal bonding layer 7. The metal bonding layer 7 includes, but is not limited to, one or more of Cr, Pt, Sn, and Au.

[0082] 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 emit light of a first wavelength, a second wavelength, and a third wavelength in sequence, and the first wavelength is smaller than the second wavelength and the third wavelength, respectively.

[0083] In one embodiment of the present invention, a first reflective structure 5 is provided on the side surface of the first light-emitting structure 1 near the insulating bonding layer 6; and the first reflective structure 5 is used to reflect light of the first wavelength and transmit light of the second wavelength and light of the third wavelength.

[0084] In one embodiment of this invention, the first reflective structure 5 includes a DBR reflector, and a current spreading layer 4 is provided on the surface of the first light-emitting structure 1 facing the first reflective structure 5. Specifically, the DBR reflector is a layered structure formed by periodically alternating growth of two materials with different refractive indices, and the optical thickness of each pair of high and low refractive index materials is 1 / 4 of the center wavelength. Preferably, the DBR reflector is formed by periodically alternating growth of TiO2 / SiO2, stacking a total of 15 layers, with thicknesses of 34nm, 19nm, 107nm, 15nm, 112nm, 29nm, 88nm, 21nm, 122nm, 26nm, 78nm, 30nm, 86nm, 13nm, and 160nm, starting from the first layer.

[0085] In one embodiment of this utility model, the current spreading layer 4 includes a transparent conductive layer, including but not limited to ITO.

[0086] In one embodiment of this utility model, the stacked Micro-LED chip further includes:

[0087] The first P electrode 12 is in contact with the P-type semiconductor layer of the first light-emitting structure 1 by being stacked on the stepped surface;

[0088] The second P electrode 13 is in contact with the P-type semiconductor layer of the second light-emitting structure 2 by being stacked on the stepped surface;

[0089] The third P electrode 14 is in contact with the P-type semiconductor layer of the third light-emitting structure 3 by being stacked on the side surface of the stacked structure away from the substrate.

[0090] The N electrode 11 is in contact with the electrode connection layer 9 by being stacked on the stepped surface.

[0091] In one embodiment of the present invention, the first P electrode 12, the second P electrode 13, the third P electrode 14, and the N electrode 11 include, but are not limited to, one or more of Ni, Al, Ti, and Au.

[0092] In one embodiment of the present invention, the second reflective structure 10 includes an insulating reflector, and the insulating reflector covers the stacked structure and exposes the first P electrode 12, the second P electrode 13, the third P electrode 14 and the N electrode 11 respectively.

[0093] In one embodiment of this utility model, the first light-emitting structure 1, the second light-emitting structure 2, and the third light-emitting structure 3 sequentially emit blue light, green light, and red light. It should be noted that when the first light-emitting structure 1 is used to emit blue light, the N-type semiconductor layer of the first light-emitting structure 1 can be, but is not limited to, an N-type gallium nitride layer; correspondingly, the P-type semiconductor layer can be, but is not limited to, a P-type gallium nitride layer. When the second light-emitting structure 2 is used to emit green light, the N-type semiconductor layer of the second light-emitting structure 2 can be, but is not limited to, an N-type gallium nitride layer; correspondingly, the P-type semiconductor layer can be, but is not limited to, a P-type gallium nitride layer. When the third light-emitting structure 3 is used to emit red light, the N-type semiconductor layer of the third light-emitting structure 3 can be, but is not limited to, an N-type AlGaInP layer; correspondingly, the P-type semiconductor layer can be, but is not limited to, a P-type AlGaInP layer. The substrate of the third light-emitting structure 3 includes, but is not limited to, a gallium arsenide substrate, and an etching stop layer is further provided between the gallium arsenide substrate and the N-type AlGaInP layer.

[0094] In one embodiment of this invention, the second reflective structure 10 includes a DBR reflector. Specifically, the DBR reflector is a layered structure formed by periodically alternating growth of two materials with different refractive indices, and the optical thickness of each pair of high and low refractive index materials is 1 / 4 of the center wavelength. Preferably, the DBR reflector is formed by periodically alternating growth of TiO2 / SiO2, with a total of 16 layers stacked, and the thicknesses from the first layer being 106nm, 54nm, 131nm, 53nm, 133nm, 51nm, 109nm, 52nm, 250nm, 44nm, 92nm, 52nm, 95nm, 50nm, 260nm, and 48nm, respectively.

[0095] In one embodiment of this invention, a current spreading layer 4 is provided on the surface of the second light-emitting structure 2 facing the first reflective structure 5. Specifically, the current spreading layer 4 includes, but is not limited to, ITO.

[0096] This utility model also provides a method for fabricating a stacked Micro-LED chip, characterized in that the fabrication method includes:

[0097] S01, provides three independently grown light-emitting structures on the substrate, such as Figure 2-4As shown, they are a first light-emitting structure 1, a second light-emitting structure 2, and a third light-emitting structure 3, each of which includes an N-type semiconductor layer, an active layer, and a P-type semiconductor layer.

[0098] 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 emit light of a first wavelength, a second wavelength, and a third wavelength in sequence, and the first wavelength is smaller than the second wavelength and the third wavelength, respectively.

[0099] In one embodiment of this utility model, the first light-emitting structure 1, the second light-emitting structure 2, and the third light-emitting structure 3 emit blue light, green light, and red light in sequence.

[0100] In one embodiment of this utility model, when the first light-emitting structure 1 is used to emit blue light, the N-type semiconductor layer 1.3 of the first light-emitting structure 1 may be, but is not limited to, an N-type gallium nitride layer, and correspondingly, the P-type semiconductor layer 1.5 may be, but is not limited to, a P-type gallium nitride layer. The substrate includes, but is not limited to, a sapphire substrate. A buffer layer 1.2 may also be provided between the growth substrate and the N-type semiconductor layer. When the second light-emitting structure 2 is used to emit green light, the N-type semiconductor layer 2.3 of the second light-emitting structure 2 may be, but is not limited to, an N-type gallium nitride layer, and correspondingly, the P-type semiconductor layer 2.5 may be, but is not limited to, a P-type gallium nitride layer. The substrate includes, but is not limited to, a sapphire substrate. A buffer layer 2.2 may also be provided between the growth substrate and the N-type semiconductor layer. When the third light-emitting structure 3 is used to emit red light, the N-type semiconductor layer 3.3 of the third light-emitting structure 3 can be, but is not limited to, an N-type AlGaInP layer. Correspondingly, the P-type semiconductor layer 3.5 can be, but is not limited to, a P-type AlGaInP layer. The substrate of the third light-emitting structure 3 includes, but is not limited to, a gallium arsenide substrate. Furthermore, an etching stop layer 3.2 is provided between the gallium arsenide substrate and the N-type AlGaInP layer. A window layer may also be provided on the surface of the P-type semiconductor layer, but this application does not limit this.

[0101] It should be noted that, in one embodiment of this utility model, the substrate of the first light-emitting structure 1 is a transparent substrate, including but not limited to a sapphire substrate, and this application does not limit it.

[0102] S02, such as Figure 5 As shown, a current spreading layer 4 and a first reflective structure 5 are sequentially formed on the surface of the first light-emitting structure 1. The first reflective structure 5 is used to reflect light of the first wavelength (which may be blue light) and transmit light of the second wavelength (which may be green light) and light of the third wavelength (which may be red light).

[0103] In one embodiment of this utility model, a current spreading layer 4 is also formed on the surface of the second light-emitting structure 2;

[0104] In one embodiment of this utility model, the first reflective structure 5 includes a DBR reflector; specifically, the DBR reflector is a layered structure formed by periodically alternating growth of two materials with different refractive indices, and the optical thickness of each pair of high and low refractive index materials is 1 / 4 of the center wavelength. Preferably, the DBR reflector is formed by periodically alternating growth of TiO2 / SiO2, stacking a total of 15 layers, with thicknesses of 34nm, 19nm, 107nm, 15nm, 112nm, 29nm, 88nm, 21nm, 122nm, 26nm, 78nm, 30nm, 86nm, 13nm, and 160nm, respectively, starting from the first layer.

[0105] In one embodiment of this utility model, the current spreading layer 4 includes a transparent conductive layer, including but not limited to ITO.

[0106] S03, such as Figure 6 As shown, the surface of the second light-emitting structure 2 (the side surface near the P-type semiconductor layer 2.5) is bonded to the surface of the first reflective structure 5 obtained in step S02 through the insulating bonding layer 6, thereby forming a structure as shown in the figure. Figure 7 The structure shown;

[0107] In one embodiment of the present invention, the insulating bonding layer 6 includes, but is not limited to, a silicon oxide bonding layer.

[0108] S04, such as Figure 8 As shown, the substrate 2.1 and buffer layer 2.2 of the second light-emitting structure 2 are removed to expose the N-type semiconductor layer 2.3 of the second light-emitting structure 2;

[0109] In one embodiment of this invention, the substrate of the second light-emitting structure 2 is removed by laser ablation technology.

[0110] S05, such as Figure 9 As shown, the substrate of the third light-emitting structure 3 is removed to expose the N-type semiconductor layer 3.3 of the third light-emitting structure 3;

[0111] In one embodiment of this utility model, a mixed solution of hydrogen peroxide, ammonia and water is used to remove the substrate (gallium arsenide substrate) of the third light-emitting structure 3 to expose the etching stop layer located between the gallium arsenide substrate and the N-type AlGaInP layer. Then, a mixed solution of phosphoric acid and hydrochloric acid is used to remove the etching stop layer to expose the N-type semiconductor layer 3.3 of the third light-emitting structure 3.

[0112] S06, such as Figure 10As shown, the N-type semiconductor layer 3.3 of the third light-emitting structure 3 is bonded to the surface of the N-type semiconductor layer 2.3 of the second light-emitting structure 2 obtained in step S04 via a metal bonding layer 7, to obtain the desired result. Figure 11 The layered structure shown;

[0113] In one embodiment of the present invention, the metal bonding layer 7 includes, but is not limited to, one or more of Cr, Pt, Sn, and Au.

[0114] S07, such as Figure 12 As shown, the stacked structure is formed into a stepped shape by etching process; specifically, the stepped surface exposes part of the N-type semiconductor layer 1.3 and part of the P-type semiconductor layer 1.5 (or part of the current spreading layer 4) of the first light-emitting structure 1, and part of the N-type semiconductor layer 2.3 (or part of the metal bonding layer 7) and part of the P-type semiconductor layer 2.5 of the second light-emitting structure 2.

[0115] In one embodiment of this invention, the stacked structure is formed into a stepped shape by photolithography and plasma etching processes.

[0116] S08, such as Figure 13 As shown, an insulating layer 8 is formed on the surface of the stacked structure, and an etching process is used to expose at least all N-type semiconductor layers (1.3 and 2.3) corresponding to the stepped surface of the insulating layer 8.

[0117] In one embodiment of the present invention, the insulating layer 8 includes, but is not limited to, one or more of silicon carbide, silicon nitride, or titanium oxide.

[0118] S09, such as Figure 14 As shown, an electrode connection layer 9 is fabricated, which is connected to all N-type semiconductor layers (1.3 and 2.3, or N-type semiconductor layer 1.3 and part of the metal bonding layer 7) corresponding to the stepped surface via the surface of the insulating layer 8;

[0119] In one embodiment of the present invention, the electrode connection layer 9 includes a metal conductive layer.

[0120] S10, such as Figure 15 As shown, a second reflective structure 10 is fabricated on the surface of the stacked structure, and an etching process is used to expose at least all the P-type semiconductor layers (1.5 and 2.5, or current spreading layer 4 and P-type semiconductor layer 2.5) corresponding to the stepped surface and a portion of the surface of the stacked structure.

[0121] The second reflective structure 10 can reflect light of a first wavelength (which may be blue light), a second wavelength (which may be green light), and a third wavelength (which may be red light).

[0122] In one embodiment of this utility model, the second reflective structure 10 includes a DBR reflector; specifically, the DBR reflector is a layered structure formed by periodically alternating growth of two materials with different refractive indices, and the optical thickness of each pair of high and low refractive index materials is 1 / 4 of the center wavelength. Preferably, the DBR reflector is formed by periodically alternating growth of TiO2 / SiO2, stacking a total of 16 layers, with thicknesses of 106nm, 54nm, 131nm, 53nm, 133nm, 51nm, 109nm, 52nm, 250nm, 44nm, 92nm, 52nm, 95nm, 50nm, 260nm, and 48nm, respectively, starting from the first layer.

[0123] S11, such as Figure 16 As shown, a first P electrode 12, a second P electrode 13, a third P electrode 14, and an N electrode 11 are fabricated.

[0124] The first P electrode 12 is in contact with the P-type semiconductor layer of the first light-emitting structure 1 by being stacked on the stepped surface;

[0125] The second P electrode 13 forms contact with the P-type semiconductor layer of the second light-emitting structure 2 by being stacked on the stepped surface;

[0126] The third P electrode 14 forms contact with the P-type semiconductor layer of the third light-emitting structure 3 by being stacked on the exposed surface of the stacked structure;

[0127] The N electrode 11 forms contact with the electrode connection layer 9 by being stacked on the stepped surface.

[0128] In one embodiment of the present invention, the first P electrode 12, the second P electrode 13, the third P electrode 14, and the N electrode 11 include, but are not limited to, one or more of Ni, Al, Ti, and Au.

[0129] As can be seen from the above technical solution, the Micro-LED chip with stacked layers provided by this utility model includes a stacked structure, wherein the stacked structure includes a first light-emitting structure 1, a second light-emitting structure 2, and a third light-emitting structure 3 sequentially stacked on the surface of a substrate, and the stacked structure is stepped; an insulating layer 8 is disposed on the sidewall of the stacked structure; and a second reflective structure 10 is disposed on the surface of the stacked structure; wherein the first light-emitting structure 1, the second light-emitting structure 2, and the third light-emitting structure 3 respectively include an N-type semiconductor layer, an active layer, and a P-type semiconductor layer, all of the N-type semiconductor layers are interconnected by an electrode connection layer 9 connected to the corresponding stepped surfaces through the surface of the insulating layer 8, and all of the P-type semiconductor layers have an electrode access area on the corresponding stepped surface; the P-type semiconductor layer of the first light-emitting structure 1 and the P-type semiconductor layer of the second light-emitting structure 2 are bonded by an insulating bonding layer 6. Based on this, by utilizing a stepped stacking technique, each of the P-type semiconductor layers has an electrode access area on its respective stepped surface. This allows for independent driving of the first light-emitting structure 1, the second light-emitting structure 2, and the third light-emitting structure 3, while maximizing wafer area savings to achieve full-color processing and reducing production costs. Furthermore, by bonding the P-type semiconductor layers of the first light-emitting structure 1 and the second light-emitting structure 2 together through an insulating bonding layer 6, the uneven bonding thickness that occurs during the bonding process of the polymer adhesive can be avoided, which can lead to incomplete etching.

[0130] Secondly, by setting the first light-emitting structure 1, the second light-emitting structure 2, and the third light-emitting structure 3 to emit light of a first wavelength, a second wavelength, and a third wavelength respectively, with the first wavelength being smaller than the second and third wavelengths, and further, a first reflective structure 5 is provided on the surface of the first light-emitting structure 1 near the insulating bonding layer 6; the first reflective structure 5 is used to reflect the first wavelength light and transmit the second and third wavelength light. Based on this, by using the first reflective structure 5 in combination with the second reflective structure 10 to reflect the light from each light-emitting structure of the stacked structure, the first wavelength light can be prevented from exciting the light of other wavelengths without blocking the second and third wavelength light from emanating from the substrate side, thus effectively solving the problem of independent control and color mixing of the stacked structure.

[0131] Next, a current spreading layer 4 is provided on the surface of the first light-emitting structure 1 and / or on the side of the second light-emitting structure 2 facing the first reflective structure 5, thereby achieving a uniform distribution of current.

[0132] This invention also provides a method for manufacturing a stacked Micro-LED chip, which achieves the above-mentioned beneficial effects while being simple, convenient, and easy to mass-produce.

[0133] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0134] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0135] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily 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 this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A Micro-LED chip with stacked layers, characterized in that, include: Substrate; A stacked structure, comprising a first light-emitting structure, a second light-emitting structure, and a third light-emitting structure sequentially stacked on the surface of a substrate, wherein the stacked structure is in a stepped shape; An insulating layer is disposed on the sidewall of the laminated structure; A second reflective structure is disposed on the surface of the stacked structure; The first light-emitting structure, the second light-emitting structure, and the third light-emitting structure respectively include an N-type semiconductor layer, an active layer, and a P-type semiconductor layer. All N-type semiconductor layers are interconnected by connecting the corresponding stepped surfaces through the electrode connection layer via the surface of the insulating layer. Each P-type semiconductor layer has an electrode access area on its respective stepped surface. The P-type semiconductor layer of the first light-emitting structure and the P-type semiconductor layer of the second light-emitting structure are bonded together by an insulating bonding layer.

2. The Micro-LED chip with stacked layers according to claim 1, characterized in that, The N-type semiconductor layer of the second light-emitting structure and the N-type semiconductor layer of the third light-emitting structure are bonded together by a metal bonding layer.

3. The Micro-LED chip with stacked layers according to claim 1, characterized in that, The first light-emitting structure, the second light-emitting structure, and the third light-emitting structure emit light of a first wavelength, a second wavelength, and a third wavelength in sequence, respectively, and the first wavelength is smaller than the second wavelength and the third wavelength, respectively.

4. The Micro-LED chip with stacked layers according to claim 3, characterized in that, A first reflective structure is provided on the side surface of the first light-emitting structure near the insulating bonding layer; and the first reflective structure is used to reflect light of the first wavelength and transmit light of the second wavelength and light of the third wavelength.

5. The Micro-LED chip with stacked layers according to claim 4, characterized in that, The first reflective structure includes a DBR reflector, and a current spreading layer is provided on the surface of the first light-emitting structure facing the first reflective structure.

6. The Micro-LED chip with stacked layers according to claim 4, characterized in that, The stacked Micro-LED chip further includes: The first P electrode is in contact with the P-type semiconductor layer of the first light-emitting structure by being stacked on the stepped surface; The second P electrode is in contact with the P-type semiconductor layer of the second light-emitting structure by being stacked on the stepped surface; The third P electrode is in contact with the P-type semiconductor layer of the third light-emitting structure by being stacked on the surface of the stacked structure away from the substrate; The N electrode is in contact with the electrode connection layer by being stacked on the stepped surface.

7. The Micro-LED chip with stacked layers according to claim 6, characterized in that, The second reflective structure includes an insulating reflector, which covers the stacked structure and exposes the first P electrode, the second P electrode, the third P electrode, and the N electrode respectively.

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

9. The Micro-LED chip with stacked layers according to claim 7, characterized in that, The second reflective structure includes a DBR reflector.

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