A micro-led light source for medical photodynamic therapy and a preparation method thereof

Abstract

The application discloses a kind of Micro-LED light sources for medical photodynamic therapy and preparation method thereof, and its Micro-LED light source includes several rectangular array distribution Micro-LED chip and narrowband filter integrated on Micro-LED chip, the Micro-LED chip includes silicon substrate, mirror metal layer, P type GaN layer, quantum well layer and N type GaN layer arranged sequentially from bottom to top, SiO2 passivation layer is deposited on mirror metal layer and arranged to extend to N type GaN layer side wall, ohmic contact metal is respectively provided on SiO2 passivation layer and N type GaN layer, narrowband filter includes dielectric layer and filter metal layer arranged sequentially on N type GaN layer from bottom to top, and a plurality of periodic distribution circular holes are arranged in filter metal layer.The application is excited by plasmon oscillation on the surface of filter to regulate and control optical field, realizes the output of very narrow spectrum and high transmittance light;With metal mirror instead of ITO conductive layer, reduce the overall resistivity of chip, further improve luminous efficiency and brightness.

Description

Technical Field

[0001] This invention relates to the field of semiconductor light-emitting device technology, and in particular to a Micro-LED light source for medical photodynamic therapy and its preparation method. Background Technology

[0002] In the field of reproductive health, reproductive tract infections and pelvic pain in my country affect all stages of life, with an incidence rate as high as 70%. Clinical research in the medical field has found that conventional drugs have limited efficacy and significant side effects, disrupt the body's normal microenvironment, are prone to recurrence after treatment, and incur huge medical costs. Photodynamic therapy, as a simple, low-side-effect, non-drug treatment method, does not directly damage human tissues and has been proven to have significant therapeutic effects on a variety of diseases.

[0003] Photodynamic therapy (PDT) is a new technology that utilizes the photodynamic effect for disease diagnosis and treatment. The process involves using a specific wavelength of light to activate a photosensitizer that selectively remains within tumor tissue. This photosensitizer reacts with oxygen within the tumor tissue, producing highly reactive singlet oxygen and other reactive free radicals. These products interact with biomolecules, disrupting the structure and function of cells and organelles, thereby selectively killing tumor cells and achieving the goal of treating tumors. The three essential elements of PDT are: a light source, oxygen, and a photosensitizer; all three are indispensable. Because PDT targets and attacks diseased cells, it requires a narrow spectrum of light within a specific wavelength range. Therefore, traditional PDT primarily uses lasers as the light source. However, laser beams have a narrow irradiation area and can only produce a single wavelength of light, resulting in high costs, poor thermal stability, and the need for specialized equipment, thus limiting their application in medicine.

[0004] In recent years, Micro-LEDs, as a novel light source, have demonstrated significant advantages such as small size, ease of integration, high luminous efficiency, low energy consumption, long lifespan, fast response speed, and high thermal stability, giving them a unique advantage in the field of non-invasive medicine. With the development of third-generation semiconductor materials and semiconductor lighting technology, Micro-LED wavelengths can now cover almost the entire spectrum, meeting the needs of various disease treatments. How to replace lasers with Micro-LEDs as a light source for photodynamic therapy is a problem that urgently needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a high-efficiency, tunable narrow-spectrum Micro-LED light source for medical photodynamic therapy and its preparation method.

[0006] The present invention provides a Micro-LED light source for medical photodynamic therapy, comprising a plurality of Micro-LED chips arranged in a rectangular array and a narrowband filter integrated on the Micro-LED chips. The Micro-LED chip comprises, from bottom to top, a silicon substrate, a mirror metal layer, a P-type GaN layer, a quantum well layer and an N-type GaN layer. A SiO2 passivation layer extending toward the sidewall of the N-type GaN layer is deposited on the mirror metal layer. Ohmic contact metals are respectively disposed on the SiO2 passivation layer and the N-type GaN layer. The narrowband filter comprises, from bottom to top, a dielectric layer and a filter metal layer arranged on the N-type GaN layer. A plurality of periodically distributed circular holes are arranged in the filter metal layer.

[0007] The quantum well layer is an InGaN / GaN multi-quantum well layer.

[0008] The dielectric layer is an aluminum oxide layer.

[0009] The present invention provides a method for preparing a Micro-LED light source suitable for medical photodynamic therapy, comprising the following steps:

[0010] S1. Fabrication of Micro-LED chips

[0011] S11. Using MOCVD process, a U-type GaN layer, an N-type GaN layer, a quantum well layer and a P-type GaN layer are grown sequentially from bottom to top on a planar sapphire substrate to prepare a Micro-LED epitaxial material.

[0012] S12. A conductive layer with a thickness of 500 (±20) nm is fabricated on a P-type GaN layer using electron beam evaporation to form the first part;

[0013] S13. A chip metal layer with a thickness of 500 (±20) nm is deposited on a silicon substrate to form the second part;

[0014] S14. The first part is flip-bonded onto the second part using a wafer bonding machine, and the chip metal layer and conductive layer are used to form a mirror metal layer, forming the third part.

[0015] S15. The planar sapphire substrate above the third part is peeled off using laser lift-off method, and then finely polished using chemical mechanical polishing method to form the fourth part;

[0016] S16. Use dry etching to completely etch the U-shaped GaN layer in the fourth step, and etch out the chip mesa to the mirror metal layer to form the fifth step.

[0017] S17. A SiO2 passivation layer is deposited on the surface of the metal layer of the mirror and the sidewalls of the P-type GaN layer, quantum well layer and N-type GaN layer using a vapor deposition method to form the sixth part, wherein the thickness of the SiO2 passivation layer is 240 (±20) nm.

[0018] S18. Photolithographically pattern the P and N electrode patterns respectively, and prepare ohmic contact metal on the N-type GaN layer and SiO2 passivation layer by electron beam evaporation to obtain the Micro-LED chip.

[0019] S2. Integrating a narrowband filter on a Micro-LED chip

[0020] S21. Using thin film deposition technology, a dielectric layer is prepared on the surface of an N-type GaN layer, and the thickness of the dielectric layer is 200 (±20) nm.

[0021] S22. Using a spin coater, electron beam resist is uniformly coated on the upper surface of the dielectric layer, and then exposed using an electron beam etching device. After cleaning, cylindrical electron beam resist units are formed in a periodic rectangular array or in a periodic equilateral hexagonal pattern.

[0022] S23. On the sample after the pattern is exposed, a filter metal layer is deposited around the cylindrical electron beam resist unit using an electron beam evaporation machine. The thickness of the filter metal layer is 40 (±10) nm.

[0023] S24. After vapor deposition, the cylindrical electron beam adhesive units in the filter metal layer are removed, so that periodically distributed circular holes are formed in the filter metal layer.

[0024] S3. Arrange and package 16 Micro-LED chips with integrated narrowband filters in a 4×4 rectangular array.

[0025] The thin film deposition process is a plasma-enhanced chemical vapor deposition process.

[0026] The filter's metal layer is made of aluminum or silver.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. By combining surface plasmon resonance and waveguide mode resonance in a collaborative design, a narrowband filter is integrated. By exciting plasmon oscillations on the filter surface to modulate the light field, the output of light with extremely narrow spectrum and high transmittance is achieved.

[0029] 2. Replace the ITO conductive layer with a metal reflector to reduce the overall resistivity of the chip and further improve luminous efficiency and brightness.

[0030] 3. Compared to traditional LEDs, the manufacturing process is more streamlined and the manufacturing cost is lower.

[0031] 4. Integrating the narrowband filter onto the LED chip makes it easier to integrate small-sized light source devices. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the Micro-LED light source for photodynamic therapy in traditional Chinese medicine according to the present invention.

[0033] Figure 2 This is a flowchart illustrating the fabrication process of the Micro-LED chip in this invention.

[0034] Figure 3 This is a process flow diagram of integrating a narrowband filter on a Micro-LED chip in this invention.

[0035] Figure 4 This is a computer simulation of the transmission spectrum of the Micro-LED light source used in photodynamic therapy in traditional Chinese medicine according to the present invention.

[0036] The markings shown in the diagram and their corresponding component names are as follows:

[0037] 1. Planar sapphire substrate; 2. U-type GaN layer; 3. N-type GaN layer; 4. Quantum well layer; 5. P-type GaN layer; 6. Conductive layer; 7. Chip metal layer; 8. Silicon substrate; 9. Mirror metal layer; 10. SiO2 passivation layer; 11. Ohmic contact metal; 12. Dielectric layer; 13. Filter metal layer; 131. Circular hole; 14. Cylindrical electron beam adhesive unit. Detailed Implementation

[0038] from Figure 1 As can be seen, the Micro-LED light source for medical photodynamic therapy of this invention includes several Micro-LED chips arranged in a rectangular array and a narrowband filter integrated on each Micro-LED chip.

[0039] from Figure 1 and Figure 2 As can be seen, the Micro-LED chip in this invention includes a silicon substrate 8, a reflective metal layer 9, a P-type GaN layer 5, a quantum well layer 4, and an N-type GaN layer 3 arranged sequentially from bottom to top. A SiO2 passivation layer 10 extending toward the sidewall of the N-type GaN layer 3 is deposited on the reflective metal layer 9. An ohmic contact metal 11 is respectively disposed on the SiO2 passivation layer 10 and the N-type GaN layer 3.

[0040] from Figure 1 and Figure 3 As can be seen, the narrowband filter in this invention includes a dielectric layer 12 and a filter metal layer 13 arranged sequentially from bottom to top on an N-type GaN layer 3, and a plurality of periodically distributed circular holes 131 are arranged in the filter metal layer 13.

[0041] In this invention, the quantum well layer 4 is an InGaN / GaN multi-quantum well layer, and the dielectric layer 12 is an aluminum oxide layer.

[0042] The present invention discloses a method for preparing a Micro-LED light source for medical photodynamic therapy, comprising the following steps:

[0043] S1. Fabrication of Micro-LED chips

[0044] S11. Using MOCVD technology, a U-type GaN layer 2, an N-type GaN layer 3, a quantum well layer 4, and a P-type GaN layer 5 are sequentially grown from bottom to top on a planar sapphire substrate 1 to fabricate a Micro-LED epitaxial material. The thickness of the U-type GaN layer 2 is 5 μm, the thickness of the N-type GaN layer 3 is 5 μm, the quantum well layer 4 is an InGaN (2 nm) / GaN (10 nm) multi-quantum well layer with a thickness of 96 nm, and the thickness of the P-type GaN layer 5 is 100 nm. The emission wavelength of the Micro-LED epitaxial material is determined by the In composition in the quantum well layer 4.

[0045] S12. A conductive layer 6 with a thickness of 500 (±20) nm is fabricated on a P-type GaN5 layer using electron beam evaporation to form the first part;

[0046] S13. A chip metal layer 7 with a thickness of 500 (±20) nm is deposited on the silicon substrate 8 to form the second part;

[0047] S14. The first part is flip-bonded onto the second part using a wafer bonding machine, and the chip metal layer 7 and conductive layer 6 are used to form a reflective metal layer 9, thus forming the third part.

[0048] S15. The planar sapphire substrate 1 above the third part is peeled off by laser lift-off and then polished by chemical mechanical polishing (CMP) to form the fourth part.

[0049] S16. Use dry etching to completely etch the U-shaped GaN layer 2 in the fourth step, and etch out the chip mesa to the mirror metal layer 9 to form the fifth step.

[0050] S17. A SiO2 passivation layer 10 is deposited on the surface of the metal layer 9 of the mirror and the sidewalls of the P-type GaN layer 5, the quantum well layer 4 and the N-type GaN layer 3 using a vapor deposition method to form the sixth part, wherein the thickness of the SiO2 passivation layer 10 is 240 (±20) nm.

[0051] S18. An ohmic contact metal 11 is prepared on the N-type GaN layer 3 and SiO2 passivation layer 10 by electron beam evaporation to obtain a Micro-LED chip.

[0052] S2. Integrating a narrowband filter on a Micro-LED chip

[0053] S21. Using a thin film deposition process, a dielectric layer 12 is prepared on the upper surface of the N-type GaN layer 3, and the thickness of the dielectric layer 12 is 200 (±20) nm.

[0054] S22. Using a spin coater, electron beam resist is uniformly coated on the upper surface of the dielectric layer 12, and then exposed using an electron beam etching device. After cleaning, cylindrical electron beam resist units 14 are formed in a periodic rectangular array or in a periodic equilateral hexagonal pattern.

[0055] S23. On the sample after the pattern is exposed, a filter metal layer 13 is deposited around the cylindrical electron beam adhesive unit 14 using an electron beam evaporation machine. The thickness of the filter metal layer 13 is 40 (±10) nm.

[0056] S24. After vapor deposition, the cylindrical electron beam adhesive unit 14 in the filter metal layer 13 is removed, so that periodically distributed circular holes 131 are formed in the filter metal layer.

[0057] S3. Arrange and package 16 Micro-LED chips with integrated narrowband filters in a 4×4 rectangular array.

[0058] In this invention, the thin film deposition process is a plasma-enhanced chemical vapor deposition process.

[0059] In this invention, the filter metal layer 13 is made of aluminum or silver.

Claims

1. A method for preparing a Micro-LED light source for medical photodynamic therapy, characterized in that... The invention includes a Micro-LED light source for medical photodynamic therapy. The Micro-LED light source includes a plurality of Micro-LED chips arranged in a rectangular array and a narrowband filter integrated on the Micro-LED chips. The Micro-LED chips include a silicon substrate (8), a mirror metal layer (9), a P-type GaN layer (5), a quantum well layer (4), and an N-type GaN layer (3) arranged sequentially from bottom to top. A SiO2 passivation layer (10) extending toward the sidewall of the N-type GaN layer is deposited on the mirror metal layer (9). Ohmic contact metals (11) are respectively disposed on the SiO2 passivation layer and the N-type GaN layer. The narrowband filter includes a dielectric layer (12) and a filter metal layer (13) arranged sequentially from bottom to top on the N-type GaN layer. A plurality of periodically distributed circular holes (131) are arranged in the filter metal layer. The preparation method includes the following steps: S1. Fabrication of Micro-LED chips S11. Using MOCVD process, a U-type GaN layer (2), an N-type GaN layer (3), a quantum well layer (4) and a P-type GaN layer (5) are grown sequentially from bottom to top on a planar sapphire substrate (1) to form a Micro-LED epitaxial material. S12. A conductive layer with a thickness of 500±20nm is fabricated on the P-type GaN layer by electron beam evaporation (6) to form the first part; S13. A chip metal layer (7) with a thickness of 500±20nm is deposited on the silicon substrate (8) to form the second part; S14. The first part is flip-bonded onto the second part by a wafer bonding machine, and the chip metal layer and conductive layer are used to form a reflective metal layer (9), forming the third part; S15. The planar sapphire substrate above the third part is peeled off using laser lift-off method, and then finely polished using chemical mechanical polishing method to form the fourth part; S16. Use dry etching to completely etch the u-shaped GaN layer (2) in the fourth part, and etch out the chip mesa to the mirror metal layer to form the fifth part; S17. A SiO2 passivation layer (10) is deposited on the surface of the metal layer of the mirror and the sidewalls of the P-type GaN layer, quantum well layer and N-type GaN layer by vapor deposition to form the sixth part, wherein the thickness of the SiO2 passivation layer is 240±20nm. S18. Photolithographically pattern the P and N electrode patterns respectively, and prepare ohmic contact metal (11) on the N-type GaN layer and SiO2 passivation layer by electron beam evaporation to obtain the Micro-LED chip. S2. Integrating a narrowband filter on a Micro-LED chip S21. Using thin film deposition process, a dielectric layer (12) is prepared on the upper surface of the N-type GaN layer. The thickness of the dielectric layer is 200±20nm. S22. Using a spin coater, electron beam resist is uniformly coated on the upper surface of the dielectric layer, and then exposed using an electron beam etching device. After cleaning, cylindrical electron beam resist units (14) are formed in a periodic rectangular array or in a periodic equilateral hexagonal pattern. S23. On the sample after the pattern is exposed, a filter metal layer (13) is deposited around the cylindrical electron beam adhesive unit using an electron beam evaporation machine. The thickness of the filter metal layer is 40±10nm. S24. After vapor deposition, the cylindrical electron beam adhesive unit in the filter metal layer is removed, so that periodically distributed circular holes are formed in the filter metal layer (131). S3. Arrange and package 16 Micro-LED chips with integrated narrowband filters in a 4×4 rectangular array.

2. The method for preparing a Micro-LED light source for medical photodynamic therapy according to claim 1, characterized in that: The quantum well layer is an InGaN / GaN multi-quantum well layer.

3. The method for preparing a Micro-LED light source for medical photodynamic therapy according to claim 1, characterized in that: The dielectric layer is an aluminum oxide layer.

4. The method for preparing a Micro-LED light source for medical photodynamic therapy according to claim 1, characterized in that: The thin film deposition process is a plasma-enhanced chemical vapor deposition process.

5. The method for preparing a Micro-LED light source for medical photodynamic therapy according to claim 1, characterized in that: The filter's metal layer is made of aluminum or silver.

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