Bicolor mu-LED and signal acquisition integrated optogenetics nerve probe and preparation method thereof

Abstract

The invention discloses a bicolor mu-LED and signal acquisition integrated optogenetics nerve probe and a preparation method thereof, and belongs to the technical field of optogenetics nerve probes. The nerve probe sequentially comprises a flexible substrate, a GaN-based multi-quantum well layer I, a band-pass filter layer, an isolation layer I, a GaN-based multi-quantum well layer II, an isolation layer II, a collection electrode layer and a passivation layer from bottom to top, in the first GaN-based multi-quantum well layer, InGaN and GaN are used for constructing a multi-quantum well layer, and in the second GaN-based multi-quantum well layer, AlGaInP is used for constructing a multi-quantum well layer, so that the mu-LED respectively shows blue light and amber light. Mu-LED excitation and energy modules are arranged at the front end and the rear end of the first GaN-based multi-quantum well layer and the front end and the rear end of the second GaN-based multi-quantum well layer respectively, and Mu-LED excitation sources and the energy modules are the same in material and structure and are connected through metal wires. The energy module receives an external light signal, converts the external light signal into an electric signal, and provides a driving current and an excitation signal for the mu-LED excitation source.

Description

Technical Field

[0001] The present invention belongs to the technical field of optogenetic neural probes, and in particular relates to an optogenetic neural probe integrating a dual-color μ-LED and a signal acquisition system and a preparation method thereof. Background Art

[0002] The human brain, nature's most complex biological information processing system, consists of hundreds of billions of neurons connected by synapses to form a sophisticated three-dimensional neural network, responsible for core physiological functions such as perception, cognition, motor control, and advanced thinking. As a key discipline in revealing the nature of consciousness and the origins of intelligence, brain science has risen to the core of the global scientific and technological innovation strategy. Its breakthroughs will have a revolutionary impact on life sciences, artificial intelligence, and medical diagnosis and treatment. The core scientific proposition of current neuroscience research focuses on how to achieve precise regulation and dynamic analysis of specific neural circuits with millisecond-level time accuracy and micron-level spatial scales.

[0003] Since its inception, optogenetics has become a vital research tool in neuroscience thanks to its unique advantages in spatiotemporal specificity. This technology, through genetic engineering, precisely expresses light-sensitive proteins in target neurons, combined with light-controlled methods to precisely switch neural activity on and off. It has achieved breakthroughs in neural circuit analysis, the study of psychiatric disease mechanisms, and neuromodulatory treatments, earning it the title "revolutionary neuroscience technology" by Nature.

[0004] Despite significant technological advantages, traditional optogenetic systems are limited by the physical connection of optical fibers and the wired power supply mode, which severely restricts the natural behavioral paradigms of experimental animals, and it is difficult to achieve precise control of single-cell resolution with millimeter-scale light spots. To address this technical bottleneck, the new generation of wireless optogenetic systems breaks through physical constraints through miniaturized energy transmission modules (such as radio frequency power supply, ultrasonic power supply, biofuel cells, etc.), but the existing discrete architecture faces key technical challenges such as insufficient integration, excessive control delay, and limited energy density. Under the premise of ensuring no damage to neural tissue and not restricting the free movement of experimental subjects, the key research goal of highly integrated, unconstrained multi-color neural probes is to achieve remote wireless power supply, multi-mode controllable excitation, high spatial resolution multi-address stimulation, and high-density signal acquisition. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention aims to provide an optogenetic neural probe integrating dual-color μ-LED with signal acquisition and a preparation method, thereby solving the problems in the prior art.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] The optogenetic neural probe integrates a dual-color μ-LED with signal acquisition, and comprises, from bottom to top, a flexible substrate, a first GaN-based multi-quantum well layer, a bandpass filter layer, a first isolation layer, a second GaN-based multi-quantum well layer, a second isolation layer, a collection electrode layer, and a passivation layer. The first GaN-based multi-quantum well layer is constructed using InGaN and GaN, while the second GaN-based multi-quantum well layer is constructed using AlGaInP, resulting in the μ-LED exhibiting blue and amber light, respectively.

[0008] μ-LED excitation and energy modules are respectively provided at the front and back ends of GaN-based multi-quantum well layer one and GaN-based multi-quantum well layer two. The μ-LED excitation source and the energy module have the same material and structure and are connected by metal wires; the energy module receives external light signals and converts them into electrical signals, and provides driving current and excitation signals to the μ-LED excitation source.

[0009] Furthermore, the energy module and the μ-LED excitation source both include a buffer layer, and above the buffer layer and in order from bottom to top are arranged: an n-type gallium nitride layer, a multi-quantum well layer, a p-type gallium nitride layer, an ITO film, and a p-type electrode; an n-type electrode is arranged on the top of the n-type gallium nitride layer;

[0010] The n-type gallium nitride layer and the p-type gallium nitride layer serve as the electron injection layer and the hole injection layer, respectively, providing free electrons and holes for recombination in the multi-quantum well layer to release photons. The ITO film serves as a transparent conductive layer, achieving uniform distribution of holes on the surface of the p-type gallium nitride layer and reducing interface reflection. The p-type electrode and the n-type electrode form a closed loop with the external circuit to drive carrier injection. The p-type electrode is connected to the p-type gallium nitride layer, and the n-type electrode is connected to the n-type gallium nitride layer.

[0011] Furthermore, the GaN-based multi-quantum well layer 1 and the GaN-based multi-quantum well layer 2 both include an isolation layer 3, which covers the buffer layer, the n-type gallium nitride layer, the multi-quantum well layer, the p-type gallium nitride layer, the ITO film, the p-type electrode, and the n-type electrode.

[0012] Furthermore, the isolation layer 1, the isolation layer 2, the isolation layer 3 and the passivation layer are all made of SiO2.

[0013] Furthermore, the collection electrode layer is provided with electrodes for collecting neuron signals.

[0014] The method for preparing the above-mentioned optogenetic neural probe integrating dual-color μ-LED and signal acquisition comprises the following steps:

[0015] S1, preparing a GaN-based multi-quantum well layer 1 on the surface of a silicon substrate;

[0016] S2, depositing an integrated distributed Bragg reflector on an upper surface of the GaN-based multi-quantum well layer by a selective area growth method to form a bandpass filter layer;

[0017] S3, using PECVD technology to deposit SiO2 on the GaN-based multi-quantum well layer 1 to form an isolation layer 1, and covering the bandpass filter layer; then covering the surface of the isolation layer 1 with a layer of photoresist;

[0018] S4, taking a cleaned silicon substrate, sequentially growing a buffer layer, an n-type gallium nitride layer, a multi-quantum well layer, and a p-type gallium nitride layer on the silicon substrate using MOCVD; then, removing the silicon substrate by wet etching, and transfer bonding onto the first isolation layer;

[0019] S5, forming a second GaN-based multi-quantum well layer on the first isolation layer;

[0020] S6, using PECVD technology to deposit SiO2 on the surface of the GaN-based multi-quantum well layer 1 to form the isolation layer 2, and then covering the upper surface of the isolation layer 2 with a layer of photoresist and thermally curing it;

[0021] S7, depositing a metal electrode on the photoresist at the upper end of the second isolation layer by electron beam evaporation technology to form a collection electrode layer;

[0022] S8, using PECVD technology to deposit SiO2 on the upper surface of the collection electrode layer to form a passivation layer, and etching holes by RIE;

[0023] S9, defining the multi-layer probe area of the passivation layer by a nitride ICP process and etching it to the silicon substrate, and then etching the silicon substrate using a double-sided deep silicon etching process to prepare a preliminary neural probe;

[0024] S10, the preliminary neural probe is fixed using thermal release tape, removed from the silicon substrate by wet etching, and then transferred to a flexible substrate.

[0025] Furthermore, the step of preparing a GaN-based multi-quantum well layer on the surface of the silicon substrate includes:

[0026] S11, sequentially growing a buffer layer, an n-type gallium nitride layer, a multi-quantum well layer, and a p-type gallium nitride layer on a silicon substrate using an MOCVD method;

[0027] S12, defining a photonic structure on the p-type gallium nitride layer using electron beam exposure technology or focused ion beam etching technology, and then realizing the desired photonic device structure using a nitride ICP process or electron beam evaporation technology;

[0028] S13, defining the platforms of the μ-LED excitation source and the energy module respectively through the nitride ICP process, and etching to the n-type gallium nitride layer;

[0029] S14, etching the buffer layer in sections using a nitride ICP etching process;

[0030] S15, depositing an ITO thin film on the surface of the p-type gallium nitride layer;

[0031] S16, depositing a p-type electrode and an n-type electrode on the surface of the ITO thin film and the n-type gallium nitride layer respectively by electron beam evaporation technology;

[0032] S17, using PECVD technology to deposit SiO2 on the upper surface of the GaN-based multi-quantum well layer 1 to form an isolation layer 3, and opening holes using RIE etching technology;

[0033] S18, depositing metal wires through electron beam evaporation technology to define the electrode interconnection between the μ-LED excitation source and the energy module.

[0034] Furthermore, the step of preparing the GaN-based multi-quantum well layer 2 on the isolation layer 1 includes:

[0035] S51, using electron beam exposure technology or focused ion beam etching technology to define the photonic structure on the p-type gallium nitride layer, and then using nitride ICP process or electron beam evaporation technology to realize the required photonic device structure;

[0036] S52, defining the platforms of the μ-LED excitation source and the energy module respectively through the nitride ICP process, and etching to the n-type gallium nitride layer;

[0037] S53, etching the buffer layer in sections using a nitride ICP etching process;

[0038] S54, depositing an ITO thin film on the surface of the p-type gallium nitride layer;

[0039] S55, depositing a p-type electrode and an n-type electrode on the surface of the ITO film and the n-type gallium nitride layer respectively by electron beam evaporation technology;

[0040] S56, using PECVD technology to deposit SiO2 on the upper surface of the GaN-based multi-quantum well layer 1 to form an isolation layer 3, and using RIE etching technology to open holes;

[0041] S57, depositing metal wires by electron beam evaporation technology to define the electrode interconnection between the μ-LED excitation source and the energy module.

[0042] The application of the above-mentioned optogenetic neural probe integrating dual-color μ-LED and signal acquisition in collecting brain neuron signals.

[0043] An optogenetic system includes the above-mentioned dual-color μ-LED and an optogenetic neural probe integrated with signal acquisition.

[0044] Beneficial effects of the present invention:

[0045] 1. This invention achieves a high-density neural interface with minimal size and weight by stacking multicolor LED films from top to bottom and integrating the energy module with the μ-LED monolithic chip. The GaN-based multi-quantum well layer between the flexible substrate and the collection electrode layer can be vertically stacked according to the excitation wavelength band corresponding to the photosensitive protein designed in the experimental setting, without exceeding the maximum device thickness, to achieve monolithic integration of a multicolor light source array.

[0046] 2. The present invention integrates electrodes for collecting neuronal signals onto this flexible substrate, creating an optoelectronically integrated multi-color flexible probe that combines multiple adjustable excitations with signal collection. Furthermore, the multi-color flexible probe device can conform to the subject being measured, with external incident light providing energy and signals. The subject does not need to be fixed, allowing optical excitation and electrical signal collection to be achieved in a free environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0048] Figure 1 Schematic diagram of the overall structure of the optogenetic neural probe of the present invention;

[0049] Figure 2 is a top view of the GaN-based multi-quantum well layer of the optogenetic neural probe of the present invention;

[0050] Figure 3 is a top view of the collection electrode layer of the optogenetic neural probe of the present invention;

[0051] Figure 4 This is a cross-sectional view of the preparation process of the GaN-based multi-quantum well layer of the optogenetic neural probe of the present invention;

[0052] Figure 5 is a flow chart for preparing the optogenetic neural probe of the present invention;

[0053] In the figure: 1-flexible substrate, 2-GaN-based multi-quantum well layer 1, 3-bandpass filter layer, 4-isolation layer 1, 5-GaN-based multi-quantum well layer 2, 6-isolation layer 2, 7-collection electrode layer, 8-passivation layer, 9-μ-LED excitation source, 10-energy module, 11-metal wire, 12-electrode, 13-silicon substrate, 14-buffer layer, 15-n-type gallium nitride layer, 16-multi-quantum well layer, 17-p-type gallium nitride layer, 18-ITO thin film, 19-p-type electrode, 20-n-type electrode, 21-isolation layer 3. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0055] Example 1

[0056] like Figures 1 to 3 As shown, the optogenetic neural probe integrating dual-color μ-LED and signal acquisition includes, from bottom to top: flexible substrate 1, GaN-based multi-quantum well layer 1 2, bandpass filter layer 3, isolation layer 1 4, GaN-based multi-quantum well layer 2 5, isolation layer 2 6, collection electrode layer 7, and passivation layer 8;

[0057] The GaN-based multi-quantum well layer 1 2 and the GaN-based multi-quantum well layer 2 5 use InGaN / GaN multi-quantum wells and AlGaInP multi-quantum wells respectively, so that their μ-LEDs respectively display blue light (470nm) and amber light (580nm).

[0058] The front and rear ends of the GaN-based multi-quantum well layer 1 2 and the GaN-based multi-quantum well layer 2 5 are respectively provided with a μ-LED excitation source 9 and an energy module 10. The μ-LED excitation source 9 and the energy module 10 have the same structure and composition but different shapes and sizes. They are prepared on the same wafer and are connected by a metal wire 11.

[0059] A bandpass filter layer 3 is added between GaN-based multi-quantum well layers with different band gaps (GaN-based multi-quantum well layer 1 2 and GaN-based multi-quantum well layer 2 5) to filter out high-energy-level incident light incident on the narrow-bandgap energy module 10, thereby achieving optical isolation between the GaN-based multi-quantum well layers and allowing each layer to work independently; at the same time, electrodes 12 for collecting neuronal signals are integrated on the flexible substrate, and the collection electrode layer 7 collects neuronal signals by contacting neurons or adjacent tissues, thereby realizing an optoelectronic integrated multi-color flexible probe that integrates multiple adjustable excitations and signal collection.

[0060] In this embodiment, if Figure 4As shown, the GaN-based multi-quantum well layer 1 2 and the GaN-based multi-quantum well layer 2 5 have the same structure and composition, both including a μ-LED excitation source 9 and an energy module 10. The μ-LED excitation source 9 and the energy module 10 have the same material and structure composition, both including a buffer layer 14. Above the buffer layer 14 and in order from bottom to top are arranged: an n-type gallium nitride layer 15, a multi-quantum well layer 16, a p-type gallium nitride layer 17, an ITO film 18 and a p-type electrode 19; an n-type electrode 20 (n-type electrode 20) is arranged on the top of the n-type gallium nitride layer 15. The area of the n-type gallium nitride layer 15 is larger than that of the multi-quantum well layer 16, and the n-type electrode 20 is side by side with the multi-quantum well layer 16); the GaN-based multi-quantum well layer 12 and the GaN-based multi-quantum well layer 25 both include an isolation layer 3 21, which covers the buffer layer 14, the n-type gallium nitride layer 15, the multi-quantum well layer 16, the p-type gallium nitride layer 17, the ITO film 18, the p-type electrode 19, and the n-type electrode 20; and a metal wire 11 is provided on the GaN-based multi-quantum well layer to realize electrode interconnection between devices;

[0061] The n-type gallium nitride layer 15 and the p-type gallium nitride layer 17 serve as electron injection layers and hole injection layers, respectively, providing free electrons and holes for recombination in the multi-quantum well layer 16 to release photons. The ITO film 18 serves as a transparent conductive layer, achieving uniform distribution of holes on the surface of the p-type gallium nitride layer 17 and reducing interface reflection. The p-type electrode 19 and the n-type electrode 20 form a closed loop with the external circuit to drive carrier injection. The p-type electrode 19 is connected to the p-type gallium nitride layer 17, and the n-type electrode 20 is connected to the n-type gallium nitride layer 15.

[0062] External light pumping is incident on the integrated energy module 10. Under the action of the built-in electric field of the GaN-based multi-quantum well pn junction, the light-excited electron and hole pairs are collected to realize light-to-electricity conversion, supplying energy and loading signals to the μ-LED excitation source.

[0063] In this embodiment, the isolation layer 1 4 , the isolation layer 2 6 , the isolation layer 3 21 and the passivation layer 8 are all made of SiO 2 , and the thickness of the isolation layer 1 4 , the isolation layer 2 6 and the passivation layer 8 are all 500 nm, and the thickness of the isolation layer 3 21 is 200 nm.

[0064] In this embodiment, the electrode 12 is made of Ti and Pt, and has thicknesses of 10 nm and 100 nm.

[0065] The flexible substrate 1 is made of polyimide.

[0066] The buffer layer 14 is made of AlN and AlGaN.

[0067] The material of the multi-quantum well layer 16 in the GaN-based multi-quantum well layer 1 2 is InGaN and GaN.

[0068] The material of the multi-quantum well layer 16 in the GaN-based multi-quantum well layer 2 5 is AlGaInP.

[0069] The p-type electrode 19 is made of Ni and Au with thicknesses of 20 nm and 200 nm respectively.

[0070] The n-type electrode 20 is made of Ti, Al, Ni, and Au, and has thicknesses of 30 nm, 120 nm, 20 nm, and 100 nm, respectively.

[0071] The bandpass filter layer 3 is a distributed Bragg reflector (DBR).

[0072] Example 2

[0073] In this example, a method for preparing the genetic neural probe described in Example 1 is proposed, such as Figure 4 and 5 As shown, the following steps are included:

[0074] S1, preparing a GaN-based multi-quantum well layer 2 on the surface of the silicon substrate 13;

[0075] S2, depositing an integrated distributed Bragg reflector (DBR) on the upper surface of the GaN-based multi-quantum well layer 1-2 by selective area growth to form a bandpass filter layer 3;

[0076] S3, using plasma enhanced chemical vapor deposition (PECVD) technology to deposit SiO2 (500 nm) on the GaN-based multi-quantum well layer 1-2 to form an isolation layer 1-4, which can cover the bandpass filter layer 3; then, a layer of photoresist (SU8) is coated on the surface of the isolation layer 1-4 by means of a smearing method;

[0077] S4, after cleaning a silicon substrate 13, a buffer layer 14, an n-type gallium nitride layer 15, a multi-quantum well layer 16 made of AlGaInP, and a p-type gallium nitride layer 17 are sequentially grown on the silicon substrate 13 using MOCVD. Then, the silicon substrate 13 is removed by wet etching and then transfer-bonded to the isolation layer 1 4.

[0078] S5, preparing a GaN-based multi-quantum well layer 2 5 on the isolation layer 1 4;

[0079] S6, using PECVD technology to deposit SiO2 (500nm) on the surface of the GaN-based multi-quantum well layer 1 5 to form an isolation layer 2 6, and then covering the upper surface of the isolation layer 2 6 with a layer of SU8 by means of a uniform coating and thermally curing;

[0080] S7, Ti (10 nm) and Pt (100 nm) are deposited on the SU8 on the upper end of the isolation layer 2 6 by electron beam evaporation technology, and the shape is defined by metal lift-off to serve as the collection electrode layer 7;

[0081] S8, using PECVD technology to deposit SiO2 (500 nm) on the upper surface of the collection electrode layer 7 to form a passivation layer 8, and then etching holes by RIE;

[0082] S9, defining the multi-layer probe region of the passivation layer 8 by a nitride inductively coupled plasma (ICP) etching process and etching to the silicon substrate 13, and then etching the silicon substrate 13 by a double-sided deep silicon etching process to prepare a preliminary neural probe;

[0083] S10 , fixing the preliminary neural probe with a thermal release tape, removing the silicon substrate 13 by wet etching, and then transferring the probe to the flexible substrate 1 .

[0084] In this embodiment, specifically:

[0085] In S1, the steps of preparing a GaN-based multi-quantum well layer 2 on the surface of the silicon substrate 13 include:

[0086] S11, a buffer layer 14, an n-type gallium nitride layer 15, a multi-quantum well layer 16 made of InGaN / GaN material, and a p-type gallium nitride layer 17 are sequentially grown on a silicon substrate 13 using an MOCVD method; wherein the buffer layer 14 has a thickness of 0.7 μm, the n-type gallium nitride layer 15 has a thickness of 2.8 μm, the multi-quantum well layer 16 made of InGaN / GaN material has a thickness of 50 nm, and the p-type gallium nitride layer 17 has a thickness of 125 nm.

[0087] S12, using electron beam lithography (EBL) or focused ion beam (FIB) etching technology to define the photonic structure on the p-type gallium nitride layer 17, and then using nitride ICP process or electron beam evaporation technology to realize the desired photonic device structure;

[0088] S13, respectively define the platforms of the μ-LED excitation source 9 and the energy module 10 through the nitride ICP process, and etch to the n-type gallium nitride layer 15 (i.e., etching the multi-quantum well layer 16); wherein, the nitride ICP is carried out in a chlorine environment at a speed of 100nm / min.

[0089] S14, etching the buffer layer 14 (i.e., etching the n-type gallium nitride layer 15) in sections by a nitride ICP etching process, and achieving electrical isolation of the device; wherein the nitride ICP is performed in a chlorine environment at a rate of 100 nm / min.

[0090] S15, depositing an ITO film 18 on the surface of the p-type gallium nitride layer 17; wherein the deposition technology adopts PECVD technology, and the process parameters are: PECVD deposition rate is 80nm / min, and the temperature is 350°C.

[0091] S16. Using electron beam evaporation, a p-type electrode 19 and an n-type electrode 20 are deposited on the surfaces of the ITO film 18 and the n-type gallium nitride layer 15, respectively, to achieve ohmic contact. The p-type electrode 19 is made of Ni and Au, with thicknesses of 20 nm and 200 nm, respectively. The n-type electrode 20 is made of Ti, Al, Ni, and Au, with thicknesses of 30 nm, 120 nm, 20 nm, and 100 nm, respectively. The electron beam evaporation process parameters are: a deposition rate of 0.5 nm / s, vacuum operation, a pressure of 5E-4 Pa, and a temperature of 300°C.

[0092] S17, using PECVD technology to deposit SiO2 (200nm) on the upper surface of the GaN-based multi-quantum well layer 5 to form an isolation layer 3 21, and using reactive ion etching (RIE) technology to realize electrode opening; wherein, the PECVD deposition rate is 80nm / min, and the deposition time is 2min30s at a temperature of 350℃; the RIE etching rate is 200nm / min, and the etching time is 60s.

[0093] S18, depositing metal wires 11 by electron beam evaporation technology to define the electrode interconnection between the μ-LED excitation source 9 and the energy module 10; wherein, the process parameters of the electron beam evaporation technology are: evaporation rate of 0.5nm / s, carried out in a vacuum environment, air pressure of 5E-4Pa, and temperature of 300°C.

[0094] In S2, the process of preparing the bandpass filter layer 3 includes:

[0095] S21, design distributed DBR through simulation and determine the DBR photonic structure;

[0096] S22, depositing a DBR on the upper surface of the GaN-based multi-quantum well layer 2 by using a selective area growth method.

[0097] In S3, when the isolation layer 4 is deposited on the GaN-based multi-quantum well layer 2 using the PECVD technology, the process parameters are: a PECVD deposition rate of 80 nm / min, and a deposition temperature of 350° C. for 375 s.

[0098] In S4, the transfer bonding process is as follows: after removing the silicon substrate 13, the buffer layer 14, the n-type gallium nitride layer 15, the AlGaInP multi-quantum well layer 16, and the p-type gallium nitride layer 17 are transferred to the thermal release tape and pressed onto the isolation layer 4 using a steel bench vise; partially cured at 180°C for 10 minutes, the thermal release tape is released from the isolation layer 4 by heating at 150°C, and the SU8 is fully cured by clamping the sample in a bench vise and placing it in a convection oven at 250°C for 1 hour to complete the bonding;

[0099] In S5, the process of preparing the GaN-based multi-quantum well layer 5 is as follows:

[0100] S51, using electron beam lithography (EBL) or focused ion beam (FIB) etching technology to define a photonic structure on the p-type gallium nitride layer 17, and then using nitride ICP process or electron beam evaporation technology to realize the desired photonic device structure;

[0101] S52, respectively define the platforms of the μ-LED excitation source 9 and the energy module 10 through the nitride ICP process, and etch to the n-type gallium nitride layer 15 (i.e., etching the multi-quantum well layer 16); wherein the nitride ICP is carried out in a chlorine environment at a speed of 100nm / min.

[0102] S53, etching the buffer layer 14 (i.e., etching the n-type gallium nitride layer 15) in sections by a nitride ICP etching process, and achieving electrical isolation of the device; wherein the nitride ICP is performed in a chlorine environment at a rate of 100 nm / min.

[0103] S54, depositing an ITO film 18 on the surface of the p-type gallium nitride layer 17; wherein the deposition technology adopts PECVD technology, and the process parameters are: PECVD deposition rate of 80nm / min, and temperature of 350°C.

[0104] S55. Using electron beam evaporation, a p-type electrode 19 and an n-type electrode 20 are deposited on the surfaces of the ITO film 18 and the n-type gallium nitride layer 15, respectively, to achieve ohmic contact. The p-type electrode 19 is made of Ni and Au, with thicknesses of 20 nm and 200 nm, respectively. The n-type electrode 20 is made of Ti, Al, Ni, and Au, with thicknesses of 30 nm, 120 nm, 20 nm, and 100 nm, respectively. The electron beam evaporation process parameters are: a deposition rate of 0.5 nm / s, vacuum operation, a pressure of 5E-4 Pa, and a temperature of 300°C.

[0105] S56, using PECVD technology to deposit SiO2 (200nm) on the upper surface of the GaN-based multi-quantum well layer 5 to form an isolation layer 3 21, and using reactive ion etching (RIE) etching technology to realize electrode opening; wherein, the PECVD deposition rate is 80nm / min, and the deposition time is 2min30s at a temperature of 350℃; the RIE etching rate is 200nm / min, and the etching time is 60s.

[0106] S57, depositing metal wires 11 by electron beam evaporation technology to define the electrical interconnection between the μ-LED excitation source 9 and the energy module 10; wherein, the process parameters of the electron beam evaporation technology are: evaporation rate of 0.5nm / s, carried out in a vacuum environment, air pressure of 5E-4Pa, and temperature of 300°C.

[0107] In S6, when the isolation layer 26 is deposited on the surface of the GaN-based multi-quantum well layer 25 using the PECVD technology, the process parameters are: PECVD deposition rate is 80nm / min, and deposition is performed at a temperature of 350°C for 375s.

[0108] In S7, Ti and Pt are deposited on SU8 using electron beam evaporation technology to form the collection electrode layer 7, wherein the thickness of Ti is 10 nm and the thickness of Pt is 100 nm; the process parameters are: evaporation rate of 0.5 nm / s, vacuum environment, gas pressure of 5E-4 Pa, and temperature of 300°C.

[0109] In S8 , the passivation layer 8 is deposited on the upper surface of the collection electrode layer 7 using PECVD technology. The process parameters are: PECVD deposition rate of 80 nm / min, deposition time of 375 s at 350°C; and RIE etching process parameters are: RIE etching rate of 200 nm / min, etching time of 150 s.

[0110] In S9 , when defining the multi-layer probe region of the passivation layer 8 by the nitride ICP process, the process parameters are: the nitride ICP is performed in a chlorine environment at a speed of 100 nm / min.

[0111] Example 3

[0112] In this example, the neural probe in Example 1 was used in SD rats to conduct experiments to verify the effect of the neural probe of the present invention.

[0113] The experimental process includes:

[0114] 1) Male Sprague-Dawley rats (250-300 g) were anesthetized with 10% chloral hydrate (3% concentration, injection volume 1.3-1.7 mL / 100 g body weight). After adequate anesthesia, the top of the skull was shaved. The surgical area was disinfected three times with iodine and then with 75% alcohol. The animals were then fixed in a stereotaxic apparatus with the skull adjusted to a horizontal position.

[0115] 2) The coordinates of the rat's motor cortex (M1 region) were determined using a stereotaxic apparatus (1.0-2.0 mm anterior to the bregma and 2.0-3.0 mm lateral to the midline). A high-speed dental drill (0.5-1.0 mm drill bit, 800-1000 rpm) was used to drill the hole. Normal saline was continuously dripped during the drilling process to prevent thermal injury. A bone window with a diameter of 3-5 mm was created, and the bone fragment was removed using microtweezers, avoiding damage to the dura mater. The dura mater was moistened with normal saline and gently incised with a 30G needle to avoid bleeding.

[0116] 3) Using microtweezers, slowly insert the multi-color flexible probe vertically to the desired depth (e.g., DV -1.8mm in the M1 region). Use a small amount of cyanoacrylate to bond the probe shaft to the skull surface. Cover and secure the probe shaft with bone cement and dental cement. The skin wound is then closed with interrupted 5-0 absorbable sutures. Apply a topical antibiotic ointment (e.g., Neosporin) to prevent infection.

[0117] 4) Seven days after surgery, the wireless μ-LED (pulse width 5 ms, frequency 20 Hz, duration 10 s) was activated, and a high-speed camera (100 fps) was used to record the movement speed and head orientation changes before, during, and after stimulation.

[0118] The above experiments show that: using optogenetics to express ChR2 and NpHR as photosensitive proteins in SD rats, the neural probe is implanted and fixed in the brain tissue of SD rats. The neural probe can be closely attached to the detection object and vertically superimposed according to the excitation light band corresponding to the photosensitive protein, realizing multiple adjustable excitation modes to stimulate specific cells in the selected brain area with light, causing the membrane potential on both sides of the cell membrane to change, thereby achieving the purpose of selective excitation or inhibition of the cells.

[0119] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0120] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. Optogenetic neural probe integrating dual-color μ-LED and signal acquisition, characterized by: From bottom to top, it includes: a flexible substrate, a GaN-based multi-quantum well layer 1, a bandpass filter layer, an isolation layer 1, a GaN-based multi-quantum well layer 2, an isolation layer 2, a collection electrode layer, and a passivation layer. The GaN-based multi-quantum well layer 1 is constructed using InGaN and GaN, while the GaN-based multi-quantum well layer 2 is constructed using AlGaInP, resulting in the μ-LEDs exhibiting blue and amber light, respectively. μ-LED excitation and energy modules are respectively provided at the front and rear ends of GaN-based multi-quantum well layer one and GaN-based multi-quantum well layer two. The μ-LED excitation source and the energy module have the same material and structure and are connected by metal wires; the energy module receives external light signals and converts them into electrical signals, and provides driving current and excitation signals to the μ-LED excitation source.

2. The optogenetic neural probe capable of regulating μ-LED optoelectronic integration according to claim 1, characterized in that: The energy module and the μ-LED excitation source both include a buffer layer, and above the buffer layer and arranged in order from bottom to top are: an n-type gallium nitride layer, a multi-quantum well layer, a p-type gallium nitride layer, an ITO film, and a p-type electrode; an n-type electrode is arranged on the top of the n-type gallium nitride layer; The n-type gallium nitride layer and the p-type gallium nitride layer serve as the electron injection layer and the hole injection layer, respectively, providing free electrons and holes for recombination in the multi-quantum well layer to release photons. The ITO film serves as a transparent conductive layer, achieving uniform distribution of holes on the surface of the p-type gallium nitride layer and reducing interface reflection. The p-type electrode and the n-type electrode form a closed loop with the external circuit to drive carrier injection. The p-type electrode is connected to the p-type gallium nitride layer, and the n-type electrode is connected to the n-type gallium nitride layer.

3. The optogenetic neural probe capable of regulating μ-LED optoelectronic integration according to claim 2, characterized in that: The GaN-based multi-quantum well layer 1 and the GaN-based multi-quantum well layer 2 both include an isolation layer 3, which covers the buffer layer, the n-type gallium nitride layer, the multi-quantum well layer, the p-type gallium nitride layer, the ITO film, the p-type electrode and the n-type electrode.

4. The optogenetic neural probe capable of regulating μ-LED optoelectronic integration according to claim 3, characterized in that: The first isolation layer, the second isolation layer, the third isolation layer and the passivation layer are all made of SiO2.

5. The optogenetic neural probe capable of regulating μ-LED optoelectronic integration according to claim 1, characterized in that: The collecting electrode layer is provided with electrodes for collecting neuron signals.

6. The method for preparing an optogenetic neural probe integrating a dual-color μ-LED and a signal acquisition system according to claim 3 or 4, characterized in that: The following steps are involved: S1, preparing a GaN-based multi-quantum well layer 1 on the surface of a silicon substrate; S2, depositing an integrated distributed Bragg reflector on the upper surface of the GaN-based multi-quantum well layer by selective area growth to form a bandpass filter layer; S3, using PECVD technology to deposit SiO2 on the GaN-based multi-quantum well layer 1 to form an isolation layer 1, and covering the bandpass filter layer; then covering the surface of the isolation layer 1 with a layer of photoresist; S4, taking a cleaned silicon substrate, sequentially growing a buffer layer, an n-type gallium nitride layer, a multi-quantum well layer, and a p-type gallium nitride layer on the silicon substrate using MOCVD; then, removing the silicon substrate by wet etching, and transfer bonding onto the first isolation layer; S5, forming a second GaN-based multi-quantum well layer on the first isolation layer; S6, using PECVD technology to deposit SiO2 on the surface of the GaN-based multi-quantum well layer 1 to form the isolation layer 2, and then covering the upper surface of the isolation layer 2 with a layer of photoresist and thermally curing it; S7, depositing a metal electrode on the photoresist at the upper end of the second isolation layer by electron beam evaporation technology to form a collection electrode layer; S8, using PECVD technology to deposit SiO2 on the upper surface of the collection electrode layer to form a passivation layer, and etching holes by RIE; S9, defining the multi-layer probe area of the passivation layer by a nitride ICP process and etching it to the silicon substrate, and then etching the silicon substrate using a double-sided deep silicon etching process to prepare a preliminary neural probe; S10, the preliminary neural probe is fixed using thermal release tape, removed from the silicon substrate by wet etching, and then transferred to a flexible substrate.

7. The method for preparing an optogenetic neural probe integrating dual-color μ-LED and signal acquisition according to claim 6, characterized in that: The steps of preparing a GaN-based multi-quantum well layer on a silicon substrate include: S11, sequentially growing a buffer layer, an n-type gallium nitride layer, a multi-quantum well layer, and a p-type gallium nitride layer on a silicon substrate using an MOCVD method; S12, defining a photonic structure on the p-type gallium nitride layer using electron beam exposure technology or focused ion beam etching technology, and then realizing the desired photonic device structure using a nitride ICP process or electron beam evaporation technology; S13, defining the platforms of the μ-LED excitation source and the energy module respectively through the nitride ICP process, and etching to the n-type gallium nitride layer; S14, etching the buffer layer in sections using a nitride ICP etching process; S15, depositing an ITO thin film on the surface of the p-type gallium nitride layer; S16, depositing a p-type electrode and an n-type electrode on the surface of the ITO thin film and the n-type gallium nitride layer respectively by electron beam evaporation technology; S17, using PECVD technology to deposit SiO2 on the upper surface of the GaN-based multi-quantum well layer 1 to form an isolation layer 3, and opening holes using RIE etching technology; S18, depositing metal wires through electron beam evaporation technology to define the electrode interconnection between the μ-LED excitation source and the energy module.

8. The method for preparing an optogenetic neural probe integrating dual-color μ-LED and signal acquisition according to claim 6, characterized in that: The steps of preparing the GaN-based multi-quantum well layer 2 on the isolation layer 1 include: S51, using electron beam exposure technology or focused ion beam etching technology to define the photonic structure on the p-type gallium nitride layer, and then using nitride ICP process or electron beam evaporation technology to realize the required photonic device structure; S52, defining the platforms of the μ-LED excitation source and the energy module respectively through the nitride ICP process, and etching to the n-type gallium nitride layer; S53, etching the buffer layer in sections using a nitride ICP etching process; S54, depositing an ITO thin film on the surface of the p-type gallium nitride layer; S55, depositing a p-type electrode and an n-type electrode on the surface of the ITO film and the n-type gallium nitride layer respectively by electron beam evaporation technology; S56, using PECVD technology to deposit SiO2 on the upper surface of the GaN-based multi-quantum well layer 1 to form an isolation layer 3, and using RIE etching technology to open holes; S57, depositing metal wires by electron beam evaporation technology to define the electrode interconnection between the μ-LED excitation source and the energy module.

9. Use of an optogenetic neural probe integrating a dual-color μ-LED and signal acquisition as described in any one of claims 1 to 5 in collecting brain neuron signals.

10. An optogenetic system, characterized in that An optogenetic neural probe comprising the dual-color μ-LED according to any one of claims 1 to 5 and integrated with signal acquisition.

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