Method for reducing power consumption of red light Micro LED

Abstract

The invention discloses a method for reducing power consumption of a red light Micro LED. The method comprises the following steps: S1, preparing a film source; s2, pretreatment cleaning; s3, photoetching forming is carried out; s4, removing residual glue; s5, removing the oxide layer; s6, composite metal deposition; s7, removing photoresist and desorbing; s8, performing appearance screening; s9, annealing treatment is conducted; s10, performance verification can also be added; the core is that a physical vapor deposition technology is adopted, a composite metal film layer containing Au, Ge and Ni is deposited in a metal deposition window, a Ni layer is located between an Au layer and a Ge layer, and by combining rapid annealing under a protective atmosphere, Ge agglomeration is inhibited, and the contact resistance of an N electrode and an n-type GaAs layer is reduced; according to the invention, low contact resistance and N-side light transmittance are both considered, substrates such as Si, sapphire and the like are compatible, the process adaptability is strong, the power consumption is reduced, the reliability and batch yield of the device are improved, and the method is suitable for the fields of Mini / Micro LED display and the like.

Description

Technical Field

[0001] This invention relates to the field of Micro LED display technology, and more specifically, to a method for reducing the power consumption of red Micro LEDs. In particular, it addresses the improvement of the ohmic contact performance between the N electrode and the n-type GaAs layer in vertical AlGaInP-based red Micro LEDs. By designing a Ni-containing composite metal film layer and adapting the process, the problem of Ge agglomeration in traditional electrodes is solved, thereby effectively reducing LED power consumption. This method can be widely used in Mini / Micro LED display panels, automotive displays, wearable devices, and other fields. Background Technology

[0002] As display technology develops towards "high resolution, high brightness, and low power consumption," AlGaInP-based red Micro LEDs have become one of the core devices for Mini / Micro LED full-color displays due to their advantages such as stable emission wavelength (620-660nm), high quantum efficiency, and long lifespan. Among them, vertical AlGaInP-based red Micro LEDs are considered the preferred architecture for high-brightness display scenarios due to their large light emission angle, strong current carrying capacity, and excellent heat dissipation performance. Their typical vertical structure, from top to bottom, includes: a fully interconnected transparent electrode, an N electrode, an n-type GaAs layer, an AlGaInP transition layer, a quantum well (light-emitting layer), a p-type AlGaInP transition layer, a GaP layer, a transparent conductive layer (such as ITO), a bonding metal layer, and a substrate (such as Si or sapphire).

[0003] In the fabrication of vertical AlGaInP-based red Micro LEDs, the ohmic contact quality between the N-electrode and the n-type GaAs layer directly determines the device's electrical performance and power consumption. Currently, the industry commonly uses an Au-Ge binary metal system to fabricate the N-electrode: after depositing an AuGe film on the surface of the n-type GaAs layer via physical vapor deposition (such as electron beam evaporation or magnetron sputtering), high-temperature annealing causes AuGe to form a eutectic liquid state, allowing Ge to diffuse into the n-type GaAs layer to increase the local doping concentration. Simultaneously, Au and Ga form Au-Ga chemical bonds, thereby reducing contact resistance. However, this process suffers from the following intractable technical drawbacks: 1. Ge agglomeration leads to abnormally high contact resistance: During high-temperature annealing, the alloying reaction between Au and Ge is incomplete, and Ge elements are prone to agglomerate into spheres (see attached). Figure 1As shown, obvious Ge agglomeration spots appear on the wafer surface without Ni. Agglomerated Ge particles disrupt the continuity of the electrode-GaAs interface, increasing contact resistance by 15%-30%, directly leading to a 0.2-0.3V increase in LED operating voltage, ultimately increasing device power consumption by 18%-25%. At the same time, Ge agglomeration also causes uneven current distribution, leading to localized current congestion and increased heat generation, further deteriorating power consumption and device reliability.

[0004] 2. Difficulty in balancing transmittance and contact resistance: The N-side (n-type GaAs layer side) of AlGaInP-based red Micro LED is the main light-emitting surface. The N-electrode metal film layer needs to balance "low contact resistance" and "high transmittance". If the thickness of the existing AuGe electrode is increased to reduce resistance, it will block more than 30% of the emitted light, resulting in a decrease in luminous efficiency. If the thin film layer is reduced to improve transmittance, the contact resistance will soar due to incomplete AuGe coverage, forming a contradiction between "resistance and transmittance".

[0005] 3. Existing improvement technologies have limitations: Some related technologies attempt to add metal elements (such as Ni and Co) to the AuGe system to suppress agglomeration, but there are obvious shortcomings: For example, some patents only mention adding Ni but do not specify the specific location of the Ni layer (such as placing the Ni layer on the outermost or innermost layer, which cannot effectively block the Ge agglomeration path); some technologies do not optimize the annealing process parameters (such as annealing temperature below 320℃ leading to insufficient AuGe eutectic, or above 380℃ leading to GaAs layer decomposition); and some technologies ignore substrate compatibility, designing processes only for GaAs substrates, which cannot be compatible with mainstream substrates such as Si and sapphire, thus limiting the scope of industrial application.

[0006] 4. Poor coordination of process parameters: In traditional processes, steps such as pretreatment cleaning (e.g., cleaning with only a single solvent), residual adhesive removal (e.g., chemical treatment to excessively corrode GaAs surface), and oxide layer removal (e.g., improper concentration of acidic solution) do not match the parameters of metal deposition and annealing processes. This not only fails to solve the Ge agglomeration problem, but may also lead to a decrease in ohmic contact stability and a device batch yield of less than 70%.

[0007] In summary, the existing N-electrode fabrication process for AlGaInP-based red Micro LEDs cannot meet the application requirements of low power consumption and high reliability due to problems such as Ge agglomeration, difficulty in achieving resistance-transmittance balance, poor process synergy, and low substrate compatibility. There is an urgent need for a technical solution that can solve the above pain points from the entire process of "film design - process optimization - performance verification". Summary of the Invention

[0008] The purpose of this invention is to overcome the technical defects existing in the fabrication of vertical structures of AlGaInP-based red Micro LEDs, specifically addressing the following issues: After high-temperature annealing of traditional AuGe electrodes, Ge tends to agglomerate into spheres, leading to increased contact resistance, uneven current distribution, and increased device power consumption; the N-electrode metal film layer cannot simultaneously achieve "low contact resistance" and "high transmittance on the N-side," resulting in a performance contradiction; in existing Ni-added improvement techniques, the Ni layer position, metal deposition parameters, and annealing process have poor synergy, limiting the effect of suppressing agglomeration; and the process adaptability is low, unable to be compatible with various substrates such as Si and sapphire, and pretreatment and residual adhesive removal steps easily damage the n-type GaAs layer, affecting yield.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for reducing the power consumption of red Micro LEDs is applied to a vertical structure of an AlGaInP-based red Micro LED containing an n-type GaAs layer. The vertical structure includes at least an n-type GaAs layer, an N-electrode in contact with the n-type GaAs layer, and a semiconductor functional layer and substrate located below the n-type GaAs layer. The method includes the following steps: S1, Source preparation: Select an AlGaInP-based red Micro LED wafer that has been bonded, with the top of the wafer being an n-type GaAs layer for forming N-electrode ohmic contacts. S2, Pre-treatment cleaning, which removes contaminants from the surface of the wafer, including: ultrasonic cleaning with an organic solvent, immersion cleaning with a polar solvent, rinsing with deionized water, and finally drying. S3, photolithography: positive photoresist is coated onto the dried wafer surface and homogenized to form a photoresist film of a preset thickness; the photoresist film is exposed through a photomask with electrode patterns, and then developed using a positive photoresist developer to form the metal deposition window of the N electrode. S4, Residual Resin Removal: Use physical bombardment or chemical treatment to remove the residual photoresist film in the metal deposition window to ensure direct contact between the subsequent metal film and the n-type GaAs layer. S5, Oxide layer removal: The wafer is soaked in an acidic solution to remove the oxide layer formed on the surface of the n-type GaAs layer due to pretreatment; S6, Composite metal deposition, using physical vapor deposition technology, depositing a composite metal film containing Au, Ge, and Ni within the metal deposition window, wherein the Ni layer is located between the Au layer and the Ge layer in the composite metal film to suppress the agglomeration of Ge during the subsequent annealing process; S7, Photoresist Removal and Desorption: The wafer after metal deposition is placed in the photoresist remover solution to peel off the photoresist and excess metal from the unexposed areas. S8, Appearance screening: Observe the wafer surface with an optical microscope to screen qualified wafers that are free of residual adhesive and residual gold; S9, Annealing treatment: The qualified wafer is placed in an annealing equipment and rapidly annealed under a protective atmosphere to form an ohmic contact with low contact resistance between the composite metal film layer and the n-type GaAs layer.

[0010] In a preferred embodiment, in step S2, the organic solvent is selected from at least one of acetone, ethanol, and ethyl acetate, the ultrasonic cleaning time is 8-15 min, and the ultrasonic power is 250-400 W; the polar solvent is selected from at least one of isopropanol and methanol, and the immersion cleaning time is 8-15 min; the drying method is nitrogen blowing or vacuum drying, and the nitrogen purity is ≥99.99% when nitrogen blowing is used.

[0011] In a preferred embodiment, in step S3, the spin-coating speed of the positive photoresist is 4000-6500 rpm, the spin-coating time is 30-60 s, and the thickness of the formed photoresist film is 4-7 μm; the electrode pattern includes at least a ring-shaped pattern for testing ohmic contact performance, the exposure time is 15-30 s, the exposure gap is 15-30 μm; the development time is 3-6 min, and the wafer is continuously oscillated during the development process to ensure sufficient development.

[0012] In a preferred embodiment, in step S4, the physical bombardment is Plasma bombardment, The plasma bombardment power is 80-150W, the oxygen flow rate is 15-30sccm, and the treatment time is 25-40s; the chemical treatment is to soak in organic amine reagents for 1-5min.

[0013] In a preferred embodiment, in step S5, the acidic solution is selected from HCl solution, , The solution or a mixture thereof, wherein the concentration of the acidic solution is 25%-45% by volume, the soaking time is 40-80s, and the soaking ambient temperature is 18-35℃.

[0014] In a preferred embodiment, in step S6, the physical vapor deposition technique is selected from at least one of electron beam evaporation, magnetron sputtering, and thermal evaporation; the structure of the composite metal film is “Au layer-Ge layer-Ni layer-Au layer-Ge layer”, “Au layer-Ni layer-Ge layer-Au layer-Ge layer”, or “Au layer-Ge layer-Ni layer-Ge layer-Au layer”, and the deposition rate of each metal layer is: 0.5-2 Å / s for the Au layer, 2-5 Å / s for the Ge layer, and 2-3.5 Å / s for the Ni layer; the thickness of each metal layer is: 20-120 Å for the Au layer, 20-120 Å for the Ge layer, and 20-45 Å for the Ni layer.

[0015] In a preferred embodiment, in step S7, the main components of the desizing solution are N-methylpyrrolidone, dimethyl sulfoxide, or a mixture thereof, the purity of the desizing solution is ≥98%, the temperature of the desizing solution is 80-100℃, the soaking time is 20-40 min, and the wafer is oscillated once every 10-25 s during the soaking process.

[0016] In a preferred embodiment, in step S9, the protective atmosphere is selected from nitrogen, argon, or a mixture thereof, and the purity of the protective atmosphere is ≥99.99%; the rapid annealing temperature is 320-390℃, the heating rate is 8-18℃ / s, the holding time is 4-8min, and the annealing is followed by cooling to room temperature.

[0017] In a preferred embodiment, in step S1, the semiconductor functional layer of the AlGaInP-based red Micro LED vertical structure includes at least an AlGaInP transition layer, a quantum well, a p-type semiconductor layer, and a transparent conductive layer; the substrate is a Si substrate, a sapphire substrate, or a GaAs substrate; and the doping concentration of the n-type GaAs layer is [missing information]. .

[0018] A preferred embodiment further includes S10: performance verification, which includes: S10-1, IV test, using a DC source meter, with a test voltage range of -15~15V and a current limit of 0.5~1.5A, requiring the IV curve to show a linear relationship; S10-2, microscopic observation, using a 50-200x optical microscope or metallographic microscope, requiring no Ge agglomeration on the surface of the composite metal film and that the film uniformity meets the preset standard.

[0019] Due to the application of the above technical solution, the beneficial effects of this application compared with the prior art are as follows: 1. Completely suppress Ge agglomeration: By placing the Ni layer between the Au and Ge layers and combining optimized deposition rate and annealing parameters, the Ge agglomeration path can be completely blocked; microscopic observation shows that there are no Ge agglomeration spots on the surface of the composite metal film, and the contact resistance is reduced by 25%-40% compared with the traditional AuGe electrode.

[0020] 2. Reduced device power consumption: The reduction in contact resistance lowers the LED operating voltage by 0.15-0.25V, reduces device power consumption by 12%-18%, improves current uniformity by more than 30%, reduces local heat generation, and extends device life by 20%.

[0021] 3. Balancing transmittance and reliability: The total thickness of the composite metal film is controlled at 200-350 Å, and the light output efficiency on the N side remains above 80%; moreover, the introduction of the Ni layer increases the bonding force between the metal film and the GaAs layer by 15%-25%.

[0022] 4. Strong process compatibility: Supports multiple deposition technologies such as electron beam evaporation and magnetron sputtering, and is compatible with various substrates such as Si, sapphire, and GaAs. The parameters of pretreatment and residual resist removal steps are mild, and the wafer batch yield has been improved from 70% to over 90%.

[0023] 5. Low industrialization cost: The metals used (Au, Ge, Ni) are commonly used materials in the semiconductor industry. No new special equipment is required. They can be directly integrated into existing Micro LED mass production lines. The unit device manufacturing cost only increases by 5%-8%, which is a significant cost-performance advantage. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 Microscopic image of a conventional AuGe electrode wafer surface; Figure 2 Microscopic images of the surface of the composite metal electrode wafer using the technology of this invention; Figure 3 This is a flowchart of a method for reducing the power consumption of red Micro LED according to Embodiment 1 of the present invention. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0028] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0029] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0030] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; 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, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] Example 1 Please see Figure 2 and 3The present invention provides a method for reducing the power consumption of red Micro LEDs. The core of this method lies in designing an "Au-Ge-Ni" composite metal film (with a Ni layer located between the Au and Ge layers, blocking the Ge agglomeration path) and matching it with a fully optimized process of "pretreatment-photolithography-metal deposition-annealing," while also being compatible with multiple substrate types. The specific technical solution is as follows: S1, Source Preparation: Select an AlGaInP-based red micro LED wafer that has been bonded. The top of the wafer is an n-type GaAs layer (doping concentration of 0.5%) used to form the N-electrode ohmic contact. High doping can reduce the contact barrier through the tunneling effect); the vertical structure of the wafer from bottom to top is as follows: substrate (Si substrate, sapphire substrate or GaAs substrate), bonding metal layer (such as AuSn, CuSn alloy), transparent conductive layer (such as p-type ITO, thickness 100-200nm), GaP layer (thickness 50-100nm, used for transition between p-type AlGaInP and ITO), p-type AlGaInP transition layer (thickness 200-300nm), quantum well (InGaP / AlGaInP multiple quantum wells, periodic 5-8 layers), n-type AlGaInP transition layer (thickness 200-300nm), n-type GaAs layer (thickness 100-200nm).

[0033] S2, Pre-treatment cleaning: A multi-step contaminant removal process is performed on the wafer surface to ensure good adhesion between subsequent metal deposition and the GaAs layer. This includes: Organic solvent ultrasonic cleaning: Select at least one of acetone, ethanol or ethyl acetate (acetone has a strong dissolving power for organic contaminants, and ethanol has a good cleaning effect on residual grease). Place the wafer in the solvent and use 250-400W power for ultrasonic cleaning for 8-15 minutes (e.g., acetone ultrasonic power of 300W for 10 minutes can effectively remove photoresist residue and cutting oil stains). Polar solvent immersion cleaning: Transfer the ultrasonically cleaned wafer to isopropanol or methanol and immerse it at room temperature for 8-15 minutes (isopropanol can dissolve residual organic solvents while avoiding oxidation of the GaAs layer). Rinse and dry with deionized water: using water with a resistivity ≥18 MΩ Rinse the wafer with deionized water for 1-3 minutes to remove solvent residue; then dry it with nitrogen gas (nitrogen purity ≥99.99%, avoid contact with air). (leading to GaAs surface oxidation) or vacuum drying (vacuum degree ≤ Pa, drying temperature 40-60℃).

[0034] S3, photolithography: Metal deposition windows for forming N-electrodes on the wafer surface specifically include: Spin coating: Apply positive photoresist (such as AZ 6130 or Shipley 1813, which has the characteristics of high resolution and fast development speed) to the surface of the dried wafer. Set the spin coater speed to 4000-6500 rpm and the time to 30-60s to form a photoresist film with a thickness of 4-7μm (too thin a film can easily lead to overdevelopment, while too thick a film can easily leave residual photoresist). Exposure: Place the coated wafer in an ultraviolet lithography apparatus (such as SUSS MA8, Canon PLA-501F) and align it with a photomask containing electrode patterns. The electrode patterns include at least a CTLM ring pattern (inner ring diameter 50-200μm, outer ring diameter 100-300μm) for testing ohmic contact performance and the electrode patterns of the actual device. Set the exposure time to 15-30s and the exposure gap to 15-30μm (too small an exposure gap can easily lead to electrode short circuits, while too large an exposure gap can waste wafer area). Development: Place the exposed wafer into a positive photoresist developer (such as AZ 300MIF, CD-26) for 3-6 minutes, during which the wafer is oscillated once every 4-6 seconds (to ensure that the photoresist in the exposed area is fully dissolved and forms a metal deposition window with neat edges).

[0035] S4, Residual Adhesive Removal: Remove residual photoresist film within the metal deposition window (a 10-50nm thick film may remain after development; failure to remove it will lead to poor metal film adhesion and increased contact resistance). One of the following two methods can be used: Physical bombardment (plasma bombardment): Preferred Plasma bombardment ( It can react with the hydrocarbon components of photoresist to generate , (No residue) Set the power to 80-150W, oxygen flow rate to 15-30sccm, and treatment time to 25-40s (e.g., 100W power, 20sccm flow rate, and 30s time can completely remove the bottom film without damaging the GaAs surface). Chemical treatment: Immerse in organic amine reagents (such as tetramethylammonium hydroxide solution, diethylamine) for 1-5 minutes (organic amines can gently dissolve the photoresist substrate and avoid acidic reagents from corroding GaAs).

[0036] S5, Oxide layer removal: After the residual adhesive is removed, gallium oxide is easily formed on the surface of the n-type GaAs layer. ), arsenic oxide ( The oxide layer (5-10 nm thick) blocks the electrical contact between the metal and GaAs and needs to be removed by soaking in an acidic solution. The acidic solution is selected from HCl solution. Solution Solution or a mixture thereof (HCl to) Strong dissolving power Can inhibit (re-deposition); Solution concentrations are defined as 25%-45% by volume (e.g., 36% HCl solution, 30%...). The solution is used for soaking for 40-80 seconds at an ambient temperature of 18-35℃ (too high a temperature can lead to over-etching of the GaAs layer, while too low a temperature will result in incomplete removal of the oxide layer).

[0037] S6, composite metal deposition: A composite metal film containing Au, Ge, and Ni was deposited within a metal deposition window using physical vapor deposition (the Ni layer is located between the Au and Ge layers; the high alloying ability of N with Au and Ge and its low surface tension inhibit Ge agglomeration). Specific parameters are as follows: Deposition technology: selected from at least one of electron beam evaporation (high film purity, thickness control accuracy ±1Å), magnetron sputtering (strong film adhesion), and thermal evaporation (low cost, suitable for mass production); Membrane structure: Options include “Au layer-Ge layer-Ni layer-Au layer-Ge layer”, “Au layer-Ni layer-Ge layer-Au layer-Ge layer” or “Au layer-Ge layer-Ni layer-Ge layer-Au layer” (preferably “Au-Ge-Ni-Au-Ge” structure, where the Ni layer is in the middle and can react with the upper and lower Ge layers simultaneously, maximizing the inhibition of aggregation). Deposition rates: Au layer: 0.5-2 Å / s (too fast a rate can lead to a loose film, too slow a rate can result in low efficiency), Ge layer: 2-5 Å / s, Ni layer: 2-3.5 Å / s; Film thickness: Au layer thickness 20-120Å (lower Au layer 20-40Å, used for bonding with GaAs; upper Au layer 80-120Å, used for protective film), Ge layer thickness 20-120Å (to ensure sufficient Ge diffusion to reduce resistance), Ni layer thickness 20-45Å (too thick will block light emission, too thin will not suppress aggregation).

[0038] S7, De-adhesive removal: Remove the photoresist and excess metal from the unexposed areas to ensure that the composite metal film remains only within the metal deposition window: Photoresist remover: The main components are N-methylpyrrolidone (NMP, which has a strong ability to dissolve photoresist), dimethyl sulfoxide (DMSO, which can improve the photoresist removal speed) or a mixture thereof, with a purity of ≥98% (impurities can cause metal film contamination). Photoresist removal parameters: Photoresist removal solution temperature 80-100℃ (increasing the temperature can accelerate the dissolution of photoresist), soaking time 20-40min, during which the wafer is oscillated up and down once every 10-25s (amplitude 4-6cm to ensure that excess metal is completely removed).

[0039] S8, Appearance Screening: Observe the wafer surface using an optical microscope (magnification 50-200x) to screen qualified wafers: Acceptance criteria: No residual adhesive or residual gold in the metal deposition window (residual adhesive can cause open circuits in the electrodes, and residual gold can cause short circuits in the electrodes), and no scratches or peeling in the composite metal film layer; Non-conforming handling: If residual adhesive / residual gold is present, return to step S2 for re-cleaning; if the film layer is detached, return to step S6 for re-deposition.

[0040] S9, Annealing treatment: Rapid annealing enables the composite metal film to form an ohmic contact with the n-type GaAs layer, resulting in low contact resistance, while simultaneously suppressing Ge agglomeration. Protective atmosphere: selected from nitrogen, argon or a mixture thereof (nitrogen is low cost, argon is more inert), purity ≥99.99% (to avoid oxidation of the metal film or decomposition of the GaAs layer); Annealing parameters: Annealing temperature 320-390℃ (AuGe cannot fully eutecticize below 320℃, and GaAs is easily decomposed above 390℃), heating rate 8-18℃ / s (rapid heating can shorten the Ge agglomeration time), holding time 4-8min (to ensure that Ge diffuses fully and does not agglomerate). Cooling method: After annealing, allow the film to cool naturally to room temperature (18-35℃) to avoid stress cracking caused by rapid cooling.

[0041] S10, Performance Verification: The annealed wafers are subjected to performance testing to ensure they meet low power consumption requirements. S10-1: IV Test: Using a DC source meter (such as Keithley 2400, Agilent B2902A), contact the positive and negative terminals of the probes to the inner and outer metal layers of the CTLM ring, respectively. The test voltage range is -15~15V, and the current is limited to 0.5~1.5A. The IV curve should show a linear relationship (linearity ≥ 0.99, proving ohmic contact), and the contact resistance should be ≤ 0.03. ; S10-2: Microscopic observation: Observe the surface of the composite metal film using a 50-200x optical microscope or metallurgical microscope (such as Olympus BX53), requiring no Ge agglomeration (see attached). Figure 2As shown, the film layer is flat and free of spots. The film layer uniformity deviation is ≤5% (the thickness of different areas is measured by a film thickness gauge, and the deviation = (maximum thickness - minimum thickness) / average thickness × 100%).

[0042] Example 2 The present invention discloses a method for reducing the power consumption of red Micro LEDs, based on AlGaInP-based red Micro LEDs on Si substrates, comprising the following steps: S1, Source Preparation: A 4-inch Si substrate AlGaInP-based red micro LED bonding wafer was selected, with an n-type GaAs layer doping concentration of [missing information]. Vertical structure (from bottom to top): Si substrate (thickness 500μm) → AuSn bonding layer (thickness 500nm) → p-type ITO (thickness 150nm) → GaP layer (thickness 80nm) → p-type AlGaInP transition layer (thickness 250nm) → InGaP / AlGaInP quantum well (6 periods) → n-type AlGaInP transition layer (thickness 250nm) → n-type GaAs layer (thickness 150nm).

[0043] S2, Pre-treatment cleaning: Organic solvent: acetone; ultrasonic power: 300W; time: 10min. Polar solvent: isopropanol, soak at room temperature for 10 minutes; Rinse with deionized water for 2 minutes, then dry with nitrogen (99.999% purity).

[0044] S3, photolithography: Positive photoresist: AZ 6130, spin coating speed 5000rpm, time 40s, film thickness 5μm; Exposure: SUSS MA8 lithography instrument, CTLM circular pattern (inner ring 100μm, outer ring 200μm), exposure time 20s, gap 20μm; Developer: AZ 300MIF, development time 4 min, oscillation frequency 1 time / 5 s.

[0045] S4, Residual Adhesive Removal: Plasma bombardment: power 100W, oxygen flow rate 20sccm, time 30s, vacuum degree Pa.

[0046] S5, Oxide layer removal: Immerse in 36% HCl solution (volume fraction) at room temperature for 60 seconds.

[0047] S6, composite metal deposition: Deposition technology: electron beam evaporation, vacuum level Pa; Membrane structure: Au layer (30 Å) - Ge layer (30 Å) - Ni layer (30 Å) - Au layer (100 Å) - Ge layer (100 Å); Deposition rates: Au layer 1 Å / s, Ge layer 3 Å / s, Ni layer 2.5 Å / s.

[0048] S7, De-adhesive removal: NMP desmear solution (99.5% purity), temperature 90℃, soak for 30 minutes, shake once every 15 seconds (amplitude 5cm).

[0049] S8, Appearance Screening:

[0050] Under a 100x optical microscope, no residual adhesive or gold was observed, and the film layer showed no scratches.

[0051] S9, Annealing treatment: Nitrogen protection (99.99% purity), annealing temperature 350℃, heating rate 11℃ / s, holding for 5 min, and then naturally cooling to 25℃.

[0052] S10, Performance Verification: IV test: Keithley 2400 DC power supply, voltage -10~10V, current limit 1A, IV curve linearity 0.995, contact resistance 0.022. ; Microscopic observation: 200x metallographic microscope, no Ge agglomeration, film uniformity deviation 3.2%.

[0053] Example 3 The present invention discloses a method for reducing the power consumption of red Micro LEDs, based on AlGaInP-based red Micro LEDs with sapphire substrates, comprising the following steps: 1. Difference parameters (compared to Example 2) S1, the substrate is a sapphire substrate (400μm thick), and the n-type GaAs layer doping concentration is... ; S2, organic solvent is ethanol, ultrasonic power 320W, time 9min; polar solvent is methanol, soaking for 11min; S6, the deposition technique is magnetron sputtering, the film structure is "Au layer (25Å)-Ni layer (25Å)-Ge layer (25Å)-Au layer (90Å)-Ge layer (90Å)", the deposition rate is: Au layer 0.8Å / s, Ge layer 2.5Å / s, Ni layer 2.2Å / s; S9, annealing temperature 330℃, heating rate 9℃ / s, holding time 4.5min; S10, IV curve linearity 0.993, contact resistance 0.025 The film uniformity deviation was 4.1%.

[0054] 2. Effects The sapphire substrate has good compatibility, low contact resistance, no Ge agglomeration, and the LED operating voltage is 2.0V, with power consumption reduced by 14% compared to traditional processes.

[0055] Example 4 The present invention discloses a method for reducing the power consumption of red Micro LEDs, based on AlGaInP-based red Micro LEDs on GaAs substrates, comprising the following steps: 1. Difference parameters (compared to Example 2) S1, the substrate is a GaAs substrate (thickness 350μm), and the n-type GaAs layer doping concentration is... ; S5, acidic solution is 30%. Soak in a mixture of 36% HCl (volume ratio 1:1) for 50 seconds.

[0056] S6, the film structure is “Au layer (35Å)-Ge layer (35Å)-Ni layer (35Å)-Ge layer (35Å)-Au layer (110Å)”, with a Ni layer thickness of 35Å; S9, annealing temperature 370℃, heating rate 13℃ / s, holding time 5.5min; S10, IV curve linearity 0.997, contact resistance 0.019 The film uniformity deviation was 2.8%.

[0057] 2. Effects The GaAs substrate has the lowest contact resistance, the LED operating voltage is 1.95V, the power consumption is reduced by 18%, and the light transmittance is 85%, making it suitable for high-brightness display scenarios.

[0058] Example effect verification: The key performance of the above embodiments was compared with that of the conventional AuGe electrode process (control group), and the results are shown in the table below:

[0059] As shown in the table above, the technical solution of the present invention is significantly superior to the traditional process in terms of key indicators such as contact resistance, power consumption, light transmittance, and yield. It is also compatible with different substrates and can meet diverse industrialization needs.

[0060] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for reducing the power consumption of red Micro LEDs, characterized in that, A vertical structure for AlGaInP-based red microLEDs containing an n-type GaAs layer, the vertical structure comprising at least an n-type GaAs layer, an N-electrode in contact with the n-type GaAs layer, and a semiconductor functional layer and a substrate located below the n-type GaAs layer, the method comprising the following steps: S1, Source preparation: Select an AlGaInP-based red Micro LED wafer that has been bonded, with the top of the wafer being an n-type GaAs layer for forming N-electrode ohmic contacts. S2, Pre-treatment cleaning, which removes contaminants from the surface of the wafer, including: ultrasonic cleaning with an organic solvent, immersion cleaning with a polar solvent, rinsing with deionized water, and finally drying. S3, photolithography: positive photoresist is coated onto the dried wafer surface and homogenized to form a photoresist film of a preset thickness; the photoresist film is exposed through a photomask with electrode patterns, and then developed using a positive photoresist developer to form the metal deposition window of the N electrode. S4, Residual Resin Removal: Use physical bombardment or chemical treatment to remove the residual photoresist film in the metal deposition window to ensure direct contact between the subsequent metal film and the n-type GaAs layer. S5, Oxide layer removal: The wafer is soaked in an acidic solution to remove the oxide layer formed on the surface of the n-type GaAs layer due to pretreatment; S6, Composite metal deposition, using physical vapor deposition technology, depositing a composite metal film containing Au, Ge, and Ni within the metal deposition window, wherein the Ni layer is located between the Au layer and the Ge layer in the composite metal film to suppress the agglomeration of Ge during the subsequent annealing process; S7, Photoresist Removal and Desorption: The wafer after metal deposition is placed in the photoresist remover solution to peel off the photoresist and excess metal from the unexposed areas. S8, Appearance screening: Observe the wafer surface with an optical microscope to screen qualified wafers that are free of residual adhesive and residual gold; S9, Annealing treatment: The qualified wafer is placed in an annealing equipment and rapidly annealed under a protective atmosphere to form an ohmic contact with low contact resistance between the composite metal film layer and the n-type GaAs layer.

2. The method for reducing the power consumption of red Micro LED according to claim 1, characterized in that, In step S2, the organic solvent is selected from at least one of acetone, ethanol, and ethyl acetate, the ultrasonic cleaning time is 8-15 min, and the ultrasonic power is 250-400 W; the polar solvent is selected from at least one of isopropanol and methanol, and the immersion cleaning time is 8-15 min; the drying method is nitrogen blowing or vacuum drying, and the nitrogen purity is ≥99.99% when nitrogen blowing.

3. The method for reducing the power consumption of red Micro LED according to claim 1, characterized in that, In step S3, the spin-coating speed of the positive photoresist is 4000-6500 rpm, the spin-coating time is 30-60 s, and the thickness of the formed photoresist film is 4-7 μm; the electrode pattern includes at least a ring-shaped pattern for testing ohmic contact performance, the exposure time is 15-30 s, the exposure gap is 15-30 μm; the development time is 3-6 min, and the wafer is continuously oscillated during the development process to ensure sufficient development.

4. The method for reducing the power consumption of red Micro LED according to claim 1, characterized in that, In step S4, the physical bombardment is Plasma bombardment, The plasma bombardment power is 80-150W, the oxygen flow rate is 15-30sccm, and the treatment time is 25-40s; the chemical treatment is to soak in organic amine reagents for 1-5min.

5. The method for reducing the power consumption of red Micro LED according to claim 1, characterized in that, In step S5, the acidic solution is selected from HCl solution, , The solution or a mixture thereof, wherein the concentration of the acidic solution is 25%-45% by volume, the soaking time is 40-80s, and the soaking ambient temperature is 18-35℃.

6. The method for reducing the power consumption of red Micro LED according to claim 1, characterized in that, In step S6, the physical vapor deposition technique is selected from at least one of electron beam evaporation, magnetron sputtering, and thermal evaporation; the structure of the composite metal film is "Au layer-Ge layer-Ni layer-Au layer-Ge layer", "Au layer-Ni layer-Ge layer-Au layer-Ge layer" or "Au layer-Ge layer-Ni layer-Ge layer-Au layer", and the deposition rate of each metal layer is: Au layer 0.5-2 Å / s, Ge layer 2-5 Å / s, Ni layer 2-3.5 Å / s; the thickness of each metal layer is: Au layer thickness 20-120 Å, Ge layer thickness 20-120 Å, Ni layer thickness 20-45 Å.

7. The method for reducing the power consumption of red Micro LED according to claim 1, characterized in that, In step S7, the main components of the desizing solution are N-methylpyrrolidone, dimethyl sulfoxide or a mixture thereof, the purity of the desizing solution is ≥98%, the temperature of the desizing solution is 80-100℃, the soaking time is 20-40min, and the wafer is oscillated once every 10-25s during the soaking process.

8. The method for reducing the power consumption of red Micro LED according to claim 1, characterized in that, In step S9, the protective atmosphere is selected from nitrogen, argon or a mixture thereof, and the purity of the protective atmosphere is ≥99.99%; the rapid annealing temperature is 320-390℃, the heating rate is 8-18℃ / s, the holding time is 4-8min, and the annealing is cooled to room temperature.

9. The method for reducing the power consumption of red Micro LED according to claim 1, characterized in that, In step S1, the semiconductor functional layer of the AlGaInP-based red Micro LED vertical structure includes at least an AlGaInP transition layer, a quantum well, a p-type semiconductor layer, and a transparent conductive layer; the substrate is a Si substrate, a sapphire substrate, or a GaAs substrate; the doping concentration of the n-type GaAs layer is [missing information]. .

10. The method for reducing the power consumption of red Micro LED according to claim 1, characterized in that, It also includes S10: performance verification, which includes: S10-1, IV test, using a DC source meter, the test voltage range is -15~15V, the current limit is 0.5~1.5A, and the IV curve is required to show a linear relationship; S10-2, microscopic observation, using a 50-200x optical microscope or metallographic microscope, requiring that there is no Ge agglomeration on the surface of the composite metal film, and the film uniformity meets the preset standard.

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