Anti-crosstalk micro-display light-emitting pixel

Abstract

The utility model discloses an anti-crosstalk micro-display light-emitting pixel, and relates to the technical field of semiconductors. The micro-display light-emitting pixel comprises a driving back plate and a display device layer on the driving back plate, wherein the display device layer comprises a light-emitting unit, an insulating layer and a groove structure; the insulating layer is formed outside the light-emitting unit in a filling manner; the groove structure penetrates through the insulating layer and surrounds the periphery of the light-emitting unit, one end of the groove structure is connected with the face, away from the driving backboard, of the light-emitting unit, and the other end of the groove structure is connected with the upper surface of the driving backboard. Based on the technical scheme provided by the invention, light emitting constraint can be carried out through the through type groove structure, and better optical crosstalk isolation is realized.

Description

[0001] This application claims priority to Chinese Patent Application No. 202311840767.0, filed on December 29, 2023, entitled "Anti-crosstalk Microdisplay Emitting Pixels and Method for Manufacturing the Same, Microdisplay," the entire contents of which are incorporated herein by reference. Technical Field

[0002] This utility model relates to the field of semiconductor technology, and in particular to a micro-display light-emitting pixel that prevents crosstalk. Background Technology

[0003] In the field of semiconductor technology, crosstalk between light-emitting pixels in microdisplays and the light emission distribution have a significant impact on display quality and the efficiency of coupled light waveguides. For example, the emission angle of a normal vertical structure light-emitting diode (LED) chip is around ±55°.

[0004] In related technologies, black matrix (BM) or microlens techniques are often used to constrain crosstalk and light emission distribution between luminescent pixels in micro-displays. In the black matrix approach, the black matrix is ​​an organic material system, which suffers from insufficient temperature resistance and mechanical strength, resulting in reliability issues. Furthermore, the black matrix absorbs light, leading to overall brightness loss. In the microlens approach, the fabricated microlenses are also made of organic materials, which also suffer from insufficient temperature resistance and mechanical strength, resulting in reliability issues. Moreover, complete optical isolation between pixels cannot be achieved. As pixel sizes continue to shrink, emission angles of ±55° can appear before entering the microlens, causing crosstalk between adjacent pixels.

[0005] Therefore, there is an urgent need to provide a new fabrication method for microdisplay light-emitting pixels that can avoid the above-mentioned defects. Utility Model Content

[0006] The purpose of this invention is to provide a micro-display luminescent pixel that prevents crosstalk, which uses a through-type groove structure to constrain light emission and achieve better optical crosstalk isolation.

[0007] To achieve the above-mentioned objectives, the present invention proposes the following technical solution:

[0008] On the one hand, a micro-display light-emitting pixel with anti-crosstalk is provided, the micro-display light-emitting pixel comprising: a driving backplate, a display device layer above the driving backplate, the display device layer comprising: a light-emitting unit, an insulating layer, and a trench structure;

[0009] A through hole is provided between the light-emitting unit and the driving back plate;

[0010] The insulating layer is formed on the outside of the light-emitting unit;

[0011] The trench structure extends through the insulating layer and surrounds the light-emitting unit. One end of the trench structure is connected to the side of the light-emitting unit away from the driving backplate, and the other end is connected to the upper surface of the driving backplate. The trench structure is filled with a metallic material, and the light-emitting unit is an inorganic compound semiconductor.

[0012] In one possible implementation, the side of the light-emitting unit closest to the driving backplate is a P-type ohmic contact layer, which is connected to a through-hole. The light-emitting unit is connected to the anode contact in the driving backplate through the through-hole filled with a metallic material.

[0013] In one possible implementation, the surface size of the through-hole is smaller than the surface size of the P-type ohmic contact layer.

[0014] In one possible implementation, the surface size of the through hole is larger than the surface size of the anode contact in the drive backplate.

[0015] In one possible implementation, the side of the light-emitting unit away from the driving backplate is an N-type ohmic contact layer, and one end of the trench structure is connected to the N-type ohmic contact layer.

[0016] In one possible implementation, the N-type ohmic contact layer includes a first portion and a second portion stacked in a direction away from the drive backplate, the second portion having a larger surface area than the first portion, and one end of the trench structure being connected to the second portion.

[0017] In one possible implementation, the second part has a roughened surface.

[0018] In one possible implementation, the trench structures corresponding to adjacent light-emitting units are interconnected;

[0019] or,

[0020] The trench structures corresponding to adjacent light-emitting units are isolated from each other by an insulating medium.

[0021] In one possible implementation, the trench pattern corresponding to the trench structure in top view includes:

[0022] One of the following: circle, rectangle, hexagon, and octagon.

[0023] In one possible implementation, the display device layer further includes: microlenses;

[0024] The microlens is disposed on the light-emitting unit and the groove structure.

[0025] In one possible implementation, the metallic material filling the trench structure includes:

[0026] Aluminum, nickel-vanadium, and copper are deposited vertically in sequence.

[0027] Or, deposited aluminum;

[0028] Or, deposited tungsten.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] By etching trench structures in the display module of microdisplay light-emitting pixels and filling the trench structures with metal materials, better optical crosstalk isolation can be achieved through the through-type trench structure. The light emission angle can be constrained by customizing the depth of the trench structure. Moreover, the design process of the trench structure is relatively mature, and mass production and yield are guaranteed.

[0031] Furthermore, the light-emitting units and trench structures in the display module belong to an inorganic material system, which has good temperature resistance and mechanical strength, and its reliability is guaranteed. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the optical crosstalk phenomenon corresponding to the relevant technologies;

[0033] Figure 2 This is a schematic diagram of the structure of a micro-display light-emitting pixel provided in an embodiment of this application;

[0034] Figure 3 This is a circuit diagram of a driving circuit provided in an embodiment of this application;

[0035] Figure 4 This is a schematic diagram of the optical crosstalk phenomenon corresponding to the embodiments of this application;

[0036] Figure 5 This is a schematic diagram of the structure of a microdisplay light-emitting pixel with a microlens provided in an embodiment of this application;

[0037] Figure 6 This is a schematic diagram of the structure of a microdisplay light-emitting pixel with a microlens provided in an embodiment of this application;

[0038] Figure 7 This is a schematic diagram of a groove pattern provided in an embodiment of this application;

[0039] Figure 8 This is a schematic diagram of the structure of a micro-display light-emitting pixel with roughened surface provided in an embodiment of this application;

[0040] Figure 9This is a flowchart of a method for fabricating a micro-display light-emitting pixel provided in an embodiment of this application;

[0041] Figure 10 This is a schematic diagram of the structure of a drive backplane provided in an embodiment of this application;

[0042] Figure 11 This is a schematic diagram of the structure of an inorganic compound semiconductor provided in the embodiments of this application;

[0043] Figure 12 This is a schematic diagram of the structure of an inorganic compound semiconductor after step etching, provided in an embodiment of this application;

[0044] Figure 13 This is a schematic diagram of the structure of an inorganic compound semiconductor after trench structure fabrication, as provided in the embodiments of this application;

[0045] Figure 14 This is a schematic diagram of the structure of an inorganic compound semiconductor filled with metal provided in the embodiments of this application;

[0046] Figure 15 This is a schematic diagram of the structure of an inorganic compound semiconductor combined with a driving backplane provided in the embodiments of this application;

[0047] Figure 16 This is a schematic diagram of the structure of an inorganic compound semiconductor after step etching, provided in an embodiment of this application.

[0048] Figure label:

[0049] 10-Drive backplane, 11-Anode contact, 21-Display device layer, 31-Light-emitting unit, 311-P-type ohmic contact layer, 312-Through hole, 313-N-type ohmic contact layer, 314-First part, 315-Second part, 316-Substrate, 317-Active quantum well layer, 41-Trench structure, 50-Microlens, 61-Insulating layer. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0051] In the description of this utility model, it should be understood that the terms "vertical," "upper," "lower," "top," "side," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0052] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0053] Traditional anti-crosstalk design schemes for microdisplay luminescent pixels have several drawbacks, such as:

[0054] The proposed anti-crosstalk design scheme for fabricating microlenses uses an organic material system, which suffers from insufficient temperature resistance and mechanical strength, resulting in reliability issues. Furthermore, complete optical isolation between pixels cannot be achieved. As pixel size continues to shrink, and the emission angle reaches ±55°, crosstalk between adjacent pixels occurs even before the light enters the microlens. Figure 1 As an example, consider a GaN Micro LED vertical structure device with a 4µm pixel size and a 2µm light-emitting unit. Its vertical structure has a minimum emission angle of ±55°, lower than the ±60-70° emission angle of horizontal and flip-chip LED devices. When the emission angle is ±55°, optical crosstalk between adjacent pixels cannot be completely isolated because the light emitted from the active light-emitting area passes through the entire light-emitting unit, becoming multi-faceted exit points. The actual light angle will be higher than... Figure 1 It is more complex because the light is refracted and reflected multiple times in the light-emitting unit, which causes more severe optical crosstalk between pixels.

[0055] For anti-crosstalk designs using black matrices, the black matrix blocks light through the light-absorbing properties of the black matrix material, achieving optical crosstalk isolation between pixels. However, black matrices are organic material systems, which have insufficient temperature resistance and mechanical strength, resulting in reliability defects. Furthermore, the light absorption of the black matrix leads to an overall brightness loss. In some solutions, a trapezoidal structure similar to the black matrix is ​​formed using metal patterning deposition and gold peeling to achieve isolation and circumvent reliability issues. However, neither the black matrix nor the metal patterning and gold peeling solution can be adapted to extremely small pixel sizes. For example, when the pixel size drops below 5µm, the resolution of the black matrix and the photoresist mask peeling problem in metal patterning and gold peeling pose challenges to yield and mass production capabilities.

[0056] To avoid the above problems, this application proposes a technical solution that uses a through-type trench structure to constrain light emission and achieve better optical crosstalk isolation.

[0057] First, the specific structure of the microdisplay light-emitting pixels proposed in this application will be described.

[0058] This application provides a micro-display light-emitting pixel (hereinafter referred to as micro-display light-emitting pixel) to prevent crosstalk, such as Figure 2 As shown, the microdisplay's light-emitting pixels include:

[0059] The driving backplate 10 and the display device layer 21 above the driving backplate 10 include: a light-emitting unit 31, an insulating layer 61, and a trench structure 41; a through hole 312 is provided between the light-emitting unit 31 and the driving backplate 10; the insulating layer 61 is filled and formed on the outside of the light-emitting unit 31; the trench structure 41 penetrates the insulating layer 61 and surrounds the light-emitting unit 31, one end of the trench structure 41 is connected to the side of the light-emitting unit 31 away from the driving backplate 10, and the other end is connected to the upper surface of the driving backplate 10; the trench structure 41 is filled with a metal material, and the light-emitting unit 31 is an inorganic compound semiconductor.

[0060] The driving backplane 10 is an active driving backplane that combines one or more of the following: thin-film transistor (TFT), low-temperature polysilicon (LTPS), CMOS integrated circuit, and high-mobility transistor (HEMT). Specifically, the driving backplane 10 is provided with a driving circuit, which has at least one anode. An exemplary circuit structure of the driving circuit is as follows: Figure 3 As shown. It should be noted that the driving circuit in this embodiment is an active drive, and the circuit diagram shown in this embodiment is only a simplified schematic diagram. The driving circuit may include active, passive, or semi-passive control circuits. All anodes included in the driving circuit can be linearly arranged or arrayed, and any anode may be located in the middle or at the edge of the driving backplate 10. This embodiment does not impose any restrictions on this.

[0061] The display device layer 21 includes a through-type trench structure 41. This trench structure 41 surrounds the light-emitting unit 31 within the display device layer 21 and is filled with a metallic material. The light-emitting unit 31 is an inorganic compound semiconductor. The overall display device layer 21 is a purely inorganic structure, exhibiting high reliability. For example,... Figure 4 As shown, the design of the trench structure 41 (i.e., the TI structure in the figure) can constrain the emission angle, thereby preventing optical crosstalk between adjacent microdisplay emission pixels.

[0062] Furthermore, such as Figure 5 , Figure 6 As shown, the display device layer 21 also includes a microlens 50; the microlens 50 is disposed on the light-emitting unit 31 and the trench structure 41. The microlens 50 can be disposed on the top of the display device layer 21. First, the trench structure 41 provides basic light emission constraint, and then the microlens 50 is used to further isolate the light emitted by the light-emitting unit 31 from optical crosstalk. The material of the microlens 50 can be a compound semiconductor, or a dielectric material such as silicon oxide or silicon nitride deposited subsequently.

[0063] Furthermore, the light-emitting unit 31 in the display module 21 is an inorganic compound semiconductor, typically a wafer or a suitably sized region cut from a wafer. Taking a wafer as an example, this wafer refers to a compound formed by two or more elements in a defined atomic ratio, possessing semiconductor properties such as a defined bandgap and band structure. Specifically, it can be a crystalline inorganic compound (such as III-V or II-VI compound semiconductors), and then an electrical contact layer is formed on the surface of the compound. During subsequent stacking of the compounds, they can be arbitrarily combined. In this embodiment, the light-emitting unit 31 involves ultraviolet, green, and blue light AlGaN and InGaN ternary material systems. Its substrate material can be GaN, Si, SiC, Sapphire, etc., as well as long-wavelength light such as red and infrared. Red light can be an InGaN ternary material system or a quaternary AlGaInP red light compound LED epitaxial layer on a GaAs substrate. Infrared light mainly includes compound epitaxial layers of InP, GaAs, and AlGaAs material systems. Furthermore, this embodiment does not limit the shape of the light-emitting unit 31 when viewed from above; it can be a circle or other polygons, such as a rectangle, hexagon, octagon, etc.

[0064] In one embodiment, when the light-emitting unit 31 includes a red light-emitting compound epitaxial layer, the red light-emitting compound epitaxial layer can be a quaternary AlGaInP or ternary InGaN material, and can be based on substrates such as GaAs, Si, Sapphire, and Ga2O3. Table 1 below shows simplified structural examples, where P-GaAs can be replaced by P-GaP and P-AlGaAs:

[0065] Table 1

[0066] Layer name Material Layer name Material P-type ohmic contact layer P-GaAs P-type ohmic contact layer P-GaN Active quantum well layer AIGaInP Active quantum well layer InGaN & GaN N-type ohmic contact layer N-GaAs N-type ohmic contact layer N-GaN Etching stop layer N-AIGaInP Etching stop layer AIN & GaN substrate N-GaAs substrate Si

[0067] In one embodiment, when the light-emitting unit 31 includes blue and green light compound semiconductors, the blue and green light compound semiconductors are InGaN ternary compounds, which can be based on substrates such as Si, Sapphire, and Ga2O3. Examples of their structures are shown in Table 2 below.

[0068] Table 2

[0069]

[0070]

[0071] In one embodiment, when the light-emitting unit 31 includes an ultraviolet compound semiconductor, the ultraviolet compound semiconductor is an AlGaN ternary compound, which can be based on substrates such as Si, Sapphire, and SiC. Examples of its structure are shown in Table 3 below:

[0072] Table 3

[0073] Layer name Material Layer name Material P-type ohmic contact layer P-GaN P-type ohmic contact layer P-GaN Active quantum well layer AIGaN & InGaN Active quantum well layer AIGaN & InGaN N-type ohmic contact layer N-GaN N-type ohmic contact layer N-GaN Buffer layer AIN & AIGaN Buffer layer AIN & GaN substrate Si substrate Sapphire

[0074] In one embodiment, when the light-emitting unit 31 includes an infrared compound semiconductor, the infrared compound semiconductor is an AlGaAs ternary compound, which can be based on substrates such as GaAs and InP. Examples of its structure are shown in Table 4 below:

[0075] Table 4

[0076] Layer name Material Layer name Material P-type ohmic contact layer P-GaAs P-type ohmic contact layer P-AlGaAs Active quantum well layer AIGaAs & GaAs Active quantum well layer AIGaAs & GaAs N-type ohmic contact layer N-GaAs N-type ohmic contact layer N-AlGaAs Etching stop layer AIGaInP Etching stop layer AIGaInP substrate GaAs substrate GaAs

[0077] As shown in Tables 1 to 4 above, different wavelengths of light-emitting devices can be obtained by selecting different compound materials to prepare devices. Based on the characteristics of different compounds, different materials can be selected as P-type and N-type ohmic contact layer materials. For example, the P-type ohmic contact layer uses ITO transparent conductive film, and the N-type ohmic contact layer uses metal In+ITO transparent conductive film, which can be used as general-purpose ohmic contact materials. Specifically, the P-type ohmic contact layer of GaN can be a single layer or stack of metals such as Ni, Au, Ag, and Al, and the N-type ohmic contact layer can be a single layer or stack of metals such as Ti, Cr, Ni, and Al. The P-type ohmic contact layer of GaAs can be a single layer, alloy, or stack of metals such as Au, Be, and Zn, and the N-type ohmic contact layer can be a single layer, alloy, or stack of metals such as Au, Ge, Ni, Pt, and In.

[0078] Furthermore, the metallic material filled in the trench structure 41 includes: sequentially vertically deposited aluminum (Al), nickel vanadium (NiV), and copper (Cu); or deposited aluminum; or deposited tungsten (W). In the trench structure 41, the filling metallic material can be obtained by plasma vapor deposition of seed layers Al and NiV followed by Cu electroplating. Al can act as a reflective metal to improve brightness, and it can also serve as an N-type ohmic contact metal etched into the N-type ohmic contact layer to achieve N-connection. NiV acts as an adhesion and barrier layer, used to adhere Al and Cu and to prevent Al migration. Cu is used for electroplating. Furthermore, NiV can be replaced by any of Ni, Ti, or TiN; the metallic material can also be a direct plasma vapor deposition at room temperature or a thermally deposited metal, such as metallic Al or metallic W. Furthermore, TiN metal deposition can be performed before Al or W deposition.

[0079] Furthermore, the groove pattern corresponding to the groove structure 41 when viewed from above includes one of the following: circle, rectangle, hexagon, and octagon. When viewed from above, the groove pattern surrounding the light-emitting unit of the microdisplay can be circle, rectangle, hexagon, octagon, etc., and this embodiment does not impose any restrictions on this.

[0080] Furthermore, the trench structures 41 corresponding to adjacent light-emitting units are interconnected; or, the trench structures 41 corresponding to adjacent light-emitting units are isolated from each other by an insulating medium. The trench structure 41 achieves the following: Figure 7 The style shown between connected pixels can also achieve the following: Figure 7 The style inside the pixel shown. Figure 7 The following is an example illustration using only circular and rectangular groove shapes.

[0081] Among them, the micro-display light-emitting pixels adopt a front trench structure design concept. In the corresponding fabrication process, the trench structure 41 is first fabricated in the display device layer 21, and then the display device layer 21 is combined with the driving backplate 10.

[0082] Specifically, such as Figure 2 As shown, the side of the light-emitting unit 31 closest to the driving backplate is a P-type ohmic contact layer 311. The P-type ohmic contact layer 311 is connected to a through-hole 312. The light-emitting unit 31 is connected to the anode contact in the driving backplate 10 through the through-hole 312 filled with metal material. The surface of the P-type ohmic contact layer 311 of the light-emitting unit 31 has a through-hole 312, which can be connected to the middle area of ​​the surface of the P-type ohmic contact layer 311.

[0083] The metal material filling the through hole 312 can be the same as or different from the metal material filling the trench structure 41, such as using the same deposited Al, NiV, and Cu.

[0084] Furthermore, the surface dimensions of the via 312 are smaller than those of the P-type ohmic contact layer 311. Furthermore, the surface dimensions of the via 312 are larger than those of the anode contacts in the drive backplane 10. Since the via 312 in the display device layer needs to be aligned and bonded to the anode contacts in the drive backplane 10, the above-mentioned dimensional design reduces the difficulty of bonding and facilitates fabrication.

[0085] Among them, the side of the light-emitting unit 31 away from the driving back plate 10 is an N-type ohmic contact layer 313, and one end of the trench structure 41 is connected to the N-type ohmic contact layer 313.

[0086] Furthermore, the N-type ohmic contact layer 313 includes a first portion 314 and a second portion 315 stacked in a direction away from the drive backplate 10. The surface size of the second portion 315 is larger than the surface size of the first portion 314, and one end of the trench structure 41 is connected to the second portion 315. The cathode electrical structure is fabricated by thinning the second portion 315.

[0087] Furthermore, such as Figure 8 As shown, the second part 315 has a roughened surface. The roughened second part 315 enhances light extraction efficiency.

[0088] The insulating layer 61 can be a single layer or a stack of dielectric layers such as silicon oxide, silicon nitride, SiC, SICN, Ti3O5, and Ni2O5. The thickness of the insulating layer 61 and the depth of the trench structure 41 are generally equal to the thickness of the light-emitting unit 31, and the depth of the trench structure 41 is limited by the thickness of the light-emitting unit 31.

[0089] Furthermore, such as Figure 5 , Figure 6 As shown, microlenses 50 can be disposed on the display device layer 21. Regarding the front trench structure design concept, in one embodiment, as... Figure 5 As shown, the microlens 50 does not cleave the N-type ohmic contact layer 313 during etching. In another embodiment, as... Figure 6 As shown, during the etching of the microlens 50, the N-type ohmic contact layer 313 is partially cut off, so that the N-type contact conducts the cathode in a certain area while completely isolating the light-emitting pixels of the microdisplay.

[0090] In summary, the micro-display light-emitting pixel provided in this application embodiment achieves better optical crosstalk isolation by etching a trench structure in the display module of the micro-display light-emitting pixel and filling the trench structure with metal material. The through-type trench structure can constrain the emission angle by customizing the depth of the trench structure. Moreover, the design process of the trench structure is relatively mature, and mass production and yield are guaranteed.

[0091] Furthermore, the light-emitting units and trench structures in the display module belong to an inorganic material system, which has good temperature resistance and mechanical strength, and its reliability is guaranteed.

[0092] The following describes the method for fabricating the micro-display light-emitting pixels described in the above embodiments. This method is used to fabricate the micro-display light-emitting pixels as described in the above embodiments. Figure 9 As shown, the method may include the following steps:

[0093] S1: Fabrication of the driving backplate.

[0094] For example, the cross-sectional structure of a single pixel driving the backplane is as follows: Figure 10 As shown, the drive backplate 10 includes a through anode contact 11, and an insulating medium is disposed around the anode contact 11.

[0095] S2: Prepare a display device layer bonded to the driving backplane. The display device layer includes a light-emitting unit and a trench structure. The light-emitting unit is connected to the anode contact in the driving backplane. The trench structure surrounds the light-emitting unit and penetrates the vertical region where the display device layer is located. The trench structure is filled with a metallic material. The light-emitting unit is an inorganic compound semiconductor.

[0096] For example, the cross-sectional structure of an inorganic compound semiconductor is as follows: Figure 11 As shown, the inorganic compound semiconductor includes at least the following layers stacked sequentially from bottom to top: substrate 316, N-type ohmic contact layer 313, active quantum well layer 317 and P-type ohmic contact layer 311.

[0097] In one possible implementation, after S2, the following step is further included: fabricating a microlens on the light-emitting unit and the trench structure. The microlens can be formed by etching, and the microlens material can be a compound semiconductor or a dielectric material such as silicon oxide or silicon nitride deposited subsequently.

[0098] Regarding the design concept of the frontal trench structure in the above embodiment, S2 may specifically include the following steps:

[0099] S211: Step etching is performed on inorganic compound semiconductors to prepare light-emitting units.

[0100] Specifically, such as Figure 12 As shown, inorganic compound semiconductors are etched stepwise using patterned etching methods such as plasma dry etching to etch down to the N-type ohmic contact layer 313, thereby fabricating the light-emitting unit 31.

[0101] S212: Use insulating material to fill the light-emitting unit with steps to form an insulating layer.

[0102] Specifically, single or stacked dielectric layers such as silicon oxide, silicon nitride, SiC, SICN, Ti3O5, and Ni2O5 are used to fill the light-emitting unit with steps, forming an insulating layer.

[0103] S213: Etch the insulating layer to form a through-hole that connects to the P-type ohmic contact layer in the light-emitting unit, as well as a trench structure surrounding the light-emitting unit.

[0104] Specifically, such as Figure 13 As shown, the insulating layer 61 is etched using patterned etching methods such as plasma dry etching to realize the via area of ​​the P-type ohmic contact layer 311 and the trench isolation around the light-emitting unit 31.

[0105] S214: The through-hole and trench structures are filled with metal material, and the light-emitting unit, insulating layer and trench structure are combined to form a display device layer.

[0106] Specifically, such as Figure 14 As shown, the through-holes 312 and trench structures 41 are filled with metal material through a metal backfilling process. For example, Al, NiV, and Cu are deposited sequentially in the through-holes 312 and trench structures 41; or Al is deposited in the through-holes 312 and trench structures 41; or W is deposited in the through-holes 312 and trench structures 41. Furthermore, after filling, chemical mechanical planarization (CMP) can be used to remove excess metal and planarize the surface of the filled metal material.

[0107] S215: Through a hybrid bonding process, the display device layer is bonded to the driving backplane. During bonding, the light-emitting unit is connected to the anode contact in the driving backplane through a through-hole filled with metal material.

[0108] like Figure 15 As shown, when combined, the through hole 312 in the display device layer 21 is connected to the anode contact 11 of the drive back plate 10, and the cathode of the display device layer 21 is connected to the common cathode of the drive back plate through the trench structure 41.

[0109] In one possible implementation, after S215, the following steps are also included: removing the compound substrate from the light-emitting unit; and roughening the surface of the light-emitting unit after removing the substrate.

[0110] The compound substrate of the first light-emitting unit after bonding is removed. By removing the substrate and thinning the compound, N-contact conduction is achieved while the cathode is thinned, reducing optical crosstalk between pixels. Furthermore, the surface of the first light-emitting unit after substrate removal is roughened to enhance light extraction efficiency.

[0111] Understandably, if the above-mentioned front groove structure design is adopted, the advantage is that it can directly form an N-type ohmic contact with the first light-emitting unit, thereby simplifying the process.

[0112] It is understandable that in steps S211 to S215 above, subsequent fabrication is based on step etching to the first N-type ohmic contact layer. In another design, this step etching can be as follows: Figure 16 The inorganic compound semiconductor, except for the substrate 316, is completely etched through. Correspondingly, a process step is added to extend the N-type ohmic contact layer and connect it to the trench structure so that the cathode of the display device layer is connected to the common cathode of the drive backplane through the trench structure.

[0113] In summary, the fabrication method of the micro-display light-emitting pixel provided in this application embodiment achieves better optical crosstalk isolation by etching a trench structure in the display module of the micro-display light-emitting pixel and filling the trench structure with metal material. The through-type trench structure can constrain the emission angle by customizing the depth of the trench structure. Moreover, the design process of the trench structure is relatively mature, and mass production and yield are guaranteed.

[0114] Furthermore, the fabrication method employs semiconductor technology, which is compatible with nanoscale operation and is more suitable for the fabrication of micro-pixel sizes.

[0115] All the above-mentioned optional technical solutions can be combined in any way to form optional embodiments of this utility model. That is, any number of embodiments can be combined to meet the needs of different application scenarios. All of these are within the protection scope of this application and will not be described in detail here.

[0116] It should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A microdisplay light-emitting pixel with anti-crosstalk feature, characterized in that, The microdisplay light-emitting pixel includes: a driving backplate and a display device layer above the driving backplate, the display device layer including: a light-emitting unit, an insulating layer, and a trench structure; A through hole is provided between the light-emitting unit and the driving back plate; The insulating layer is formed on the outside of the light-emitting unit; The trench structure extends through the insulating layer and surrounds the light-emitting unit. One end of the trench structure is connected to the side of the light-emitting unit away from the driving backplate, and the other end is connected to the upper surface of the driving backplate. The trench structure is filled with a metallic material, and the light-emitting unit is an inorganic compound semiconductor.

2. The microdisplay light-emitting pixel according to claim 1, characterized in that, The side of the light-emitting unit closest to the driving backplate is a P-type ohmic contact layer, and the P-type ohmic contact layer is connected to the through hole. The light-emitting unit is connected to the anode contact in the driving backplate through the through hole filled with metal material.

3. The microdisplay light-emitting pixel according to claim 2, characterized in that, The surface dimensions of the through-hole are smaller than the surface dimensions of the P-type ohmic contact layer.

4. The microdisplay light-emitting pixel according to claim 3, characterized in that, The surface dimensions of the through hole are larger than the surface dimensions of the anode contacts in the drive backplate.

5. The microdisplay light-emitting pixel according to claim 1, characterized in that, The side of the light-emitting unit away from the driving backplate is an N-type ohmic contact layer, and one end of the trench structure is connected to the N-type ohmic contact layer.

6. The microdisplay light-emitting pixel according to claim 5, characterized in that, The N-type ohmic contact layer includes a first portion and a second portion stacked in a direction away from the drive backplate, wherein the surface size of the second portion is larger than the surface size of the first portion, and one end of the trench structure is connected to the second portion.

7. The microdisplay light-emitting pixel according to claim 6, characterized in that, The second part has a roughened surface.

8. The microdisplay light-emitting pixel according to claim 1, characterized in that, The trench structures corresponding to adjacent light-emitting units are interconnected; or, The trench structures corresponding to adjacent light-emitting units are isolated from each other by an insulating medium.

9. The microdisplay light-emitting pixel according to claim 1, characterized in that, The trench pattern corresponding to the top view of the trench structure includes: One of the following: circle, rectangle, hexagon, and octagon.

10. The microdisplay light-emitting pixel according to claim 1, characterized in that, The display device layer further includes: microlenses; The microlens is disposed on the light-emitting unit and the groove structure.

11. The microdisplay light-emitting pixel according to claim 1, characterized in that, The metallic material filling the trench structure includes: Aluminum, nickel-vanadium, and copper are deposited vertically in sequence. Or, deposited aluminum; Or, deposited tungsten.

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