A method for fabricating gallium oxide photodetectors based on reactive ion etching to enhance synaptic effects.

Abstract

This invention discloses a method for fabricating a gallium oxide photodetector based on reactive ion etching to enhance the synaptic effect, comprising the following specific steps: Step 1: Growing a gallium oxide layer on a substrate; Step 2: Patterning the gallium oxide layer using photolithography; Step 3: Etching the gallium oxide layer; Step 4: Forming a gallium oxide substrate on the etched gallium oxide layer using photolithography, and depositing a stacked metal on the surface of the gallium oxide layer; after peeling the gallium oxide layer and the stacked metal from the substrate, an electrode is obtained; Step 5: Annealing the electrode to alloy it and form an ohmic contact. This invention uses reactive ion etching to etch the gallium oxide layer, inducing the formation of more oxygen vacancies within the gallium oxide layer, thereby effectively enhancing the synaptic properties of the gallium oxide photodetector in biomimetic applications; it can better meet the needs of large-scale industrial applications while reducing manufacturing costs and process difficulty.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device fabrication technology, and in particular to a method for fabricating gallium oxide photodetectors based on reactive ion etching to enhance the synaptic effect. Background Technology

[0002] With the rapid development of fields such as artificial intelligence and machine vision, the demand for information storage and computing power is constantly increasing. Traditional computer neuromorphic network systems, by simulating the connections between neurons and synapses, have significantly improved the parallelism and energy efficiency of data processing, achieving important results in applications such as large AI models, image recognition, and speech processing. However, these systems are still based on the von Neumann architecture, and the separation of computation and storage leads to bottlenecks such as high power consumption, high latency, and limited bandwidth when processing large-scale neural networks, making it difficult to meet the computing demands of more efficient intelligence. In contrast, the human brain exhibits superior information processing capabilities with its highly parallel, low-energy, strong memory, and high fault tolerance characteristics, inspiring research into brain-like neuromorphic devices. Biomimetic neural synapse devices, by simulating the dynamic plasticity of biological synapses at the physical level, achieve intrinsic parallel computing and storage fusion, becoming a key technological path to break through the limitations of traditional computing architectures and build a new generation of neuromorphic systems.

[0003] In the field of neuromorphic bionics, photodetectors have become an important research direction for brain-like visual systems due to their high responsivity, high detectivity, high signal-to-noise ratio, and excellent low-light response characteristics. Unlike traditional neuromorphic synaptic devices that input electrical signals, photodetectors can directly convert light signals into electrical signals, endowing the device with the ability to sense ambient light. Further integration with artificial synaptic elements such as memristors and ferroelectric devices enables synaptic bionic responses to parameters such as light intensity and wavelength, and simulates the plasticity of biological synapses. This empowers systems to simultaneously possess light perception, memory, and learning capabilities, driving the development of highly energy-efficient and intelligent neuromorphic visual systems.

[0004] Among them, gallium oxide-based photodetectors have attracted much attention due to their sensitive detection of the solar-blind ultraviolet band (200-280nm). Because the Earth's ozone layer blocks ultraviolet radiation with wavelengths below 280nm, almost no ultraviolet light from the sun reaches the Earth, resulting in extremely low background noise in this band, which is beneficial for achieving high-precision ultraviolet detection. Based on this, gallium oxide solar-blind ultraviolet detectors have significant application value in fields such as flame detection, short-range ultraviolet communication, biological / chemical detection, and missile early warning.

[0005] Currently, research on gallium oxide-based photodetectors in the field of neural synapse bionics mainly focuses on improving the synaptic response characteristics and sensitivity to optical signals by growing high-quality gallium oxide thin films and using doping control. High-quality thin films can effectively reduce defect density and increase carrier mobility, thereby enhancing photoelectric response and synaptic plasticity; doping control, on the other hand, achieves fine-tuning and optimization of synaptic behavior by adjusting carrier concentration and energy level structure. However, both approaches generally suffer from complex processes and high equipment and material costs. The growth of high-quality thin films requires stringent equipment and process conditions, and the uniformity and precise control of the doping process also present technical challenges, making it difficult to meet the demands of large-scale and low-cost manufacturing. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and to provide a method for fabricating gallium oxide photodetectors based on reactive ion etching to enhance the synaptic effect.

[0007] The objective of this invention is achieved through the following technical solution: a method for fabricating a gallium oxide photodetector based on reactive ion etching to enhance the synaptic effect, comprising the following specific steps:

[0008] Step 1: Grow a gallium oxide layer on the substrate;

[0009] Step 2: Photolithography is used to pattern the gallium oxide layer;

[0010] Step 3: Etching the gallium oxide layer; Boron trichloride generates boron dichloride cations under plasma excitation, which react with oxygen ions in gallium oxide to form volatile products, thereby forming oxygen vacancies; Argon ions are used as a physical sputtering source to bombard and destroy the gallium oxygen bond structure, causing oxygen atoms to detach from the lattice and thus form oxygen vacancies.

[0011] Step 4: A gallium oxide substrate is formed by photolithography on the etched gallium oxide layer, and a stacked metal is deposited on the surface of the gallium oxide layer. The gallium oxide layer and the stacked metal are then peeled off from the substrate to obtain the electrode.

[0012] Step 5: Anneal the electrodes to alloy them and form ohmic contacts.

[0013] Preferably, in step one, the gallium oxide layer is grown using any one of metal-organic chemical vapor deposition, pulsed laser deposition, or molecular beam epitaxy.

[0014] Preferably, in step three, when etching the gallium oxide layer, the flow rate of boron trichloride is 25-35 sccm, the flow rate of argon is 5-15 sccm, the etching pressure is 0.5-1 Pa, the RF power is 100 W, and the ICP power is 800 W.

[0015] Preferably, in step four, the stacked metals sequentially include a titanium metal layer, an aluminum metal layer, a nickel metal layer, and a gold metal layer.

[0016] Preferably, in step four, a multilayer metal is formed on the surface of the gallium oxide substrate by magnetron sputtering, electron beam evaporation, or thermal evaporation.

[0017] Preferably, in step five, the electrodes are annealed using a rapid thermal annealing device or a tubular annealing furnace. The annealing is carried out in a nitrogen atmosphere at a temperature of 470°C for 1 minute.

[0018] Preferably, the substrate is a sapphire substrate or a silicon substrate.

[0019] Preferably, before growing a gallium oxide layer on the substrate, the substrate is first organically cleaned. The specific method is as follows: the substrate is ultrasonically cleaned sequentially with acetone, isopropanol and deionized water, with each cleaning time being 5 minutes. After each cleaning, the substrate is dried with a nitrogen gun. After organic cleaning, the substrate is cleaned with piranha solution for 30 minutes to remove dangling bonds, surface states and contaminants on the substrate surface.

[0020] Preferably, the gallium oxide photodetector is used in information demodulation; it converts letters or symbols into binary sequences containing "0" or "1", where "0" indicates no light pulse in the corresponding time period and "1" indicates a light pulse in the corresponding time period; each binary sequence corresponds to a light pulse mode, and each light pulse mode has a specific number of light pulses and a light pulse interval; by controlling the number of light pulses and the light pulse interval, the gallium oxide photodetector generates an excitatory postsynaptic current with a specific amplitude, and each light pulse mode corresponds to a unique current response; the current response output by the gallium oxide photodetector demodulates the input binary sequence, thereby restoring and storing the corresponding letter or symbol information.

[0021] The beneficial effects of this invention are as follows: This invention etches the gallium oxide layer using reactive ion etching. Utilizing the physical sputtering (argon ion bombardment) and chemical reaction (reaction of boron dichloride cations with oxygen ions in gallium oxide) during the etching process, more oxygen vacancies are induced within the gallium oxide layer, thereby effectively enhancing the synaptic properties of the gallium oxide photodetector in biomimetic applications. The introduction of oxygen vacancies not only increases the carrier concentration but also increases the trapped state density, significantly enhancing the device's sensitivity to optical signals and synaptic plasticity. Compared to traditional methods relying on high-quality thin film growth or doping control, the process of this invention requires no additional steps or complex material systems. The process flow is simple, easy to control, and highly compatible with existing micro / nano fabrication processes. It can better meet the needs of large-scale industrial applications while reducing manufacturing costs and process difficulty. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the gallium oxide substrate.

[0023] Figure 2 The current response curve of the gallium oxide photodetector when stimulated by an ultraviolet light pulse at a time interval of 2 seconds is shown.

[0024] Figure 3 This diagram illustrates the variation of the facilitation factor (PPF) for light pulses at different time intervals.

[0025] Figure 4 The current response diagram of a gallium oxide photodetector when four optical pulses with a 0.1s interval are applied consecutively in a text information demodulation application is shown.

[0026] Figure 5 This is a schematic diagram showing the unique EPSC response corresponding to different optical pulse modes.

[0027] In the figure: 1. First interdigital electrode region, 2. Second interdigital electrode region, 3. First gallium oxide region, 4. Second gallium oxide region. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0029] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0030] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0031] like Figures 1 to 5 As shown, a method for fabricating a gallium oxide photodetector based on reactive ion etching to enhance the synaptic effect includes the following specific steps:

[0032] Step 1: Grow a gallium oxide layer on the substrate;

[0033] Step 2: Photolithography is used to pattern the gallium oxide layer;

[0034] Step 3: Etching the gallium oxide layer; Boron trichloride generates boron dichloride cations under plasma excitation, which react with oxygen ions in gallium oxide to form volatile products, thereby forming oxygen vacancies; Argon ions are used as a physical sputtering source to bombard and destroy the gallium oxygen bond structure, causing oxygen atoms to detach from the lattice and thus form oxygen vacancies.

[0035] Step 4: A gallium oxide substrate is formed by photolithography on the etched gallium oxide layer, and a stacked metal is deposited on the surface of the gallium oxide layer. The gallium oxide layer and the stacked metal are then peeled off from the substrate to obtain the electrode.

[0036] Step 5: Anneal the electrodes to alloy them and form ohmic contacts.

[0037] This invention employs reactive ion etching (RIE) to etch gallium oxide (GaO) layers. Utilizing the physical sputtering (argon ion bombardment) and chemical reaction (reaction of boron dichloride cations with oxygen ions in GaO) during the etching process, more oxygen vacancies are induced within the GaO layer, effectively enhancing the synaptic properties of GaO photodetectors in biomimetic applications. The introduction of oxygen vacancies not only increases carrier concentration but also increases trapped state density, significantly enhancing the device's sensitivity to optical signals and synaptic plasticity. Compared to traditional methods relying on high-quality thin film growth or doping control, this invention's process requires no additional steps or complex material systems. The process flow is simple, easy to control, and highly compatible with existing micro / nano fabrication processes, enabling it to better meet the demands of large-scale industrial applications while reducing manufacturing costs and process complexity.

[0038] Gallium oxide (Ga2O3) is intrinsically a wide-bandgap semiconductor with extremely low intrinsic carrier concentration and poor conductivity. Oxygen vacancies, on the other hand, are positively charged center defects: when an oxygen atom detaches from the crystal lattice to form a vacancy, it releases a free electron (either by losing an electron and leaving a hole, or by providing an electron through a defect energy level). This transforms gallium oxide from an insulator or high-resistivity semiconductor into an n-type semiconductor, significantly increasing the carrier concentration. This increased carrier concentration directly enhances the material's conductivity, ensuring more efficient transport of photogenerated carriers, reducing losses during transport, and providing a sufficient carrier basis for synaptic effects (such as the generation of excitatory postsynaptic currents).

[0039] Theoretically, fluorine-containing gases (such as CF4 and SF6) or chlorine gases can be used as reactive ion etching gases when etching gallium oxide layers. These gases have a certain reducing property and, under plasma excitation conditions, can preferentially react with oxygen in the oxide to generate volatile products such as CO and CO2, thereby introducing oxygen vacancies into the gallium oxide (Ga2O3) material. However, fluorine-based gases and Cl2 have low reactivity when etching gallium oxide, resulting in a slow etching rate and a long overall etching process, leading to the formation of argon ions (Ar... + Prolonged bombardment of the material surface can easily cause surface roughening of the gallium oxide layer, thus adversely affecting the electrical performance of the device. In this invention, using a mixture of boron trichloride and argon (BCl3 / Ar) as the etching atmosphere can significantly improve etching efficiency and optimize surface morphology. During the etching process, boron dichloride cations (BCl2) generated from BCl3 under plasma excitation... + It can react with oxygen ions in gallium oxide to produce the volatile product B3Cl3O. 3， This results in the loss of oxygen ions in the gallium oxide layer, creating oxygen vacancies. During this reaction, a non-volatile byproduct, boron trioxide (B₂O₃), may also be generated. Boron trioxide may accumulate on the surface of the gallium oxide layer, affecting the continuity of the etching reaction. Introducing argon ions solves this problem; argon gas, under plasma excitation, forms high-energy argon ions (Ar). + Argon ions, used as a physical sputtering source, bombard the material surface at high speed, effectively removing residual boron trioxide (B2O3) and maintaining the chemical etching reaction. Furthermore, the physical bombardment of argon ions can disrupt the gallium-oxygen bond structure (Ga-O), causing oxygen atoms to detach from the lattice and form oxygen vacancies. Simultaneously, Ga... 3+ Ions retained in the crystal lattice help to enhance the electronic activity and synaptic response of the device.

[0040] In this application, after obtaining the electrode, the electrode is annealed to alloy it and form an ohmic contact. An ohmic contact refers to a "barrier-free" or "low-barrier" contact formed between a metal electrode and a semiconductor material, allowing charge carriers (electrons or holes) to flow freely bidirectionally between the electrode and the semiconductor with almost no additional resistance.

[0041] During annealing, atoms on the metal electrode and gallium oxide surface interdiffusion form a stable metal-semiconductor alloy phase, which fuses at the boundary between the gallium oxide layer and the multilayer alloy. This metal-semiconductor alloy phase reduces the native potential barrier at the interface (gallium oxide surfaces often form high barriers due to defects or oxidation), resulting in a significant reduction in resistance at the boundary.

[0042] Low contact resistance ensures that photogenerated carriers (such as electrons provided by oxygen vacancies) can be efficiently transported from the gallium oxide layer to the electrode, reducing signal loss and making the amplitude of the excitatory postsynaptic current more stable and the response faster (avoiding current delay or attenuation caused by excessive resistance).

[0043] In addition, from a structural perspective, the annealing process allows the boundaries between the stacked metal and the gallium oxide layer to fuse together, resulting in a stronger bond and a more stable structure.

[0044] Specifically, in step one, when preparing the gallium oxide layer, the gallium oxide layer can be grown using any one of metal-organic chemical vapor deposition, pulsed laser deposition, or molecular beam epitaxy.

[0045] Before growing a gallium oxide layer on the substrate, the substrate is first organically cleaned. Specifically, the substrate is ultrasonically cleaned sequentially with acetone, isopropanol, and deionized water, each cleaning session lasting 5 minutes. After each cleaning, the substrate is dried with a nitrogen gun. Following organic cleaning, the substrate is cleaned with a piranha solution for 30 minutes to remove dangling bonds, surface states, and contaminants from the substrate surface. The piranha solution is composed of concentrated sulfuric acid and hydrogen peroxide in a ratio of 3:1.

[0046] Acetone, as a highly polar organic solvent, can dissolve organic contaminants such as grease, photoresist residue, and fingerprints on the substrate surface. Isopropanol further dissolves residual acetone and, through its high volatility, reduces surface water residue after cleaning. Ultrasonic cleaning (high-frequency vibration generating microbubble rupture) enhances the impact force of the liquid, causing contaminants to detach from the substrate surface; a 5-minute cleaning time is sufficient to remove most organic impurities. Nitrogen gun drying avoids secondary pollution from airborne dust during traditional air drying and prevents salt crystals from forming after moisture evaporation.

[0047] Ultrasonic cleaning with deionized water can remove residual organic cleaning fluid (such as acetone decomposition products) and inorganic dust adsorbed from the air from the substrate surface, preventing these impurities from forming "nucleation centers" during gallium oxide growth and causing uneven composition of the growth layer.

[0048] Piranha solution possesses strong oxidizing and acidic properties, capable of thoroughly decomposing trace amounts of hydrocarbons that may remain after organic cleaning, converting them into carbon dioxide and water for evaporation and removal. Furthermore, piranha solution exhibits a slight chemical etching effect on the substrate surface, removing inorganic particles (such as small silica particles) adhering to the substrate surface while smoothing out nanoscale surface protrusions.

[0049] Meanwhile, the piranha solution can passivate dangling bonds and surface states, and form a stable oxide layer by oxidizing the unsaturated bonds on the substrate surface, thereby eliminating the capture centers of charge carriers by the surface states.

[0050] In this embodiment, the substrate material can be either a sapphire substrate or a silicon substrate.

[0051] In step three, when etching the gallium oxide layer, the synergistic effect of chemical reaction and physical sputtering must be considered in the selection and proportion control of the etching gas. In this application, when etching the gallium oxide layer, the flow rate of boron trichloride is 25-35 sccm, the flow rate of argon is 5-15 sccm, the etching pressure is 0.5-1 Pa, the RF power is 100 W, and the ICP power is 800 W. ICP power refers to inductively coupled plasma power.

[0052] Experiments show that when the flow rate of boron trichloride (BCl3) is controlled at 25-35 sccm and the flow rate of argon is 5-15 sccm, the etching rate is relatively high, and the surface of gallium oxide maintains good flatness after etching, which is beneficial to the stable performance of subsequent devices.

[0053] Previous studies have demonstrated through X-ray photoelectron (XPS) spectroscopy that the oxygen vacancy content in the gallium oxide layer increases significantly after reactive ion etching (RIE). This indicates that during RIE, physical bombardment and chemical reactions can effectively break some gallium-oxygen bonds (Ga–O), promoting the removal of oxygen atoms and thus introducing more oxygen vacancies into the crystal lattice.

[0054] In step four, electrode patterns are photolithographically patterned on the etched gallium oxide layer to form a gallium oxide substrate; subsequent stacked metals will be deposited on this gallium oxide substrate.

[0055] like Figure 1 As shown, the gallium oxide substrate includes a first interdigital electrode region 1 and a second interdigital electrode region 2. The first interdigital electrode region 1 has several equally spaced first gallium oxide regions 3, and the second interdigital electrode region 2 has several equally spaced second gallium oxide regions 4. The first gallium oxide regions 3 and the second gallium oxide regions 4 are arranged alternately. Both the first gallium oxide regions 3 and the second gallium oxide regions 4 are elongated strip structures.

[0056] By using staggered gallium oxide regions, the contact interface area between electrodes is significantly increased, which facilitates charge transport and separation, thereby improving device performance. Furthermore, the staggered arrangement structure allows for a larger inter-electrode area within a limited chip area, increasing device integration density.

[0057] The spacing between adjacent gallium oxide regions is 10um-100um, and the length of the gallium oxide region is 100um-1000um.

[0058] In step four, the stacked metal on the gallium oxide surface is formed by depositing multiple different metal materials to create a multilayer metal structure. In this embodiment, the stacked metal sequentially includes a titanium metal layer, an aluminum metal layer, a nickel metal layer, and a gold metal layer.

[0059] In the preparation of multilayer metals, multilayer metals can be formed on the surface of gallium oxide substrates by magnetron sputtering, electron beam evaporation, or thermal evaporation.

[0060] In step five, the electrodes are annealed using a rapid thermal annealing device or a tubular annealing furnace. The annealing is carried out in a nitrogen atmosphere at a temperature of 470°C for 1 minute.

[0061] The gallium oxide photodetector of this application can be used in information demodulation; it converts letters or symbols into binary sequences containing "0" or "1", where "0" indicates no light pulse in the corresponding time period and "1" indicates a light pulse in the corresponding time period; each binary sequence corresponds to a light pulse mode, and each light pulse mode has a specific number of light pulses and a light pulse interval; by controlling the number of light pulses and the light pulse interval, the gallium oxide photodetector generates an excitatory postsynaptic current with a specific amplitude, and each light pulse mode corresponds to a unique current response; the current response output by the gallium oxide photodetector demodulates the input binary sequence, thereby restoring and storing the corresponding letter or symbol information.

[0062] Figure 2 The current response curve of the prepared gallium oxide photodetector is shown when it is stimulated by ultraviolet light pulses at a time interval of 2 s. Figure 3 This demonstrates the changes in the pulse pair facilitation (PPF) exponent at different time intervals. In biomimetic research on neural synapses, postsynaptic excitation current (EPSC) is a key parameter for measuring the synaptic response characteristics of devices. EPSC refers to the instantaneous current generated after a single light pulse stimulus is applied to the device. Typically, EPSC reaches its peak at the end of the light pulse and then gradually decays. This behavior is highly consistent with biological synaptic responses and can be used to assess synaptic connection strength. Notably, a longer relaxation time of EPSC indicates a stronger ability of the device to retain light stimulus memory, which helps improve the learning efficiency, memory capacity, and system stability of artificial neural networks, demonstrating good synaptic characteristics. PPF is a typical manifestation of short-term synaptic plasticity, reflecting the enhanced response capability of a device to a second stimulus under continuous double-pulse stimulation. Figure 2 As shown, the EPSC excited by the second light pulse is significantly greater than that of the first, indicating that the device possesses PPF characteristics. The PPF index is used to quantitatively evaluate this enhancement effect, and its calculation formula is as follows:

[0063] PPF = 100% × A2 / A1;

[0064] A1 and A2 represent the peak currents of the EPSC after the first and second light pulse stimulation, respectively.

[0065] from Figure 3 As observed, the PPF index decreases significantly with increasing time interval between two light pulses. This phenomenon is highly consistent with the PPF behavior in biological synapses: when the pulse interval is short, the EPSC generated by the first stimulus has not yet fully decayed, allowing for more effective current superposition during the second stimulus, resulting in a higher PPF index. However, as the time interval lengthens, the first EPSC has nearly decayed to baseline, making it difficult for the second pulse to achieve a superposition effect, thus decreasing the PPF index. The above experimental results verify that the device of this invention possesses excellent synaptic-like behavior.

[0066] Figure 4 and Figure 5 This invention demonstrates the application of the gallium oxide photodetector in text information demodulation. Using the American Standard Code for Information Interchange (ASCII), binary information of "0" and "1" can be converted into corresponding letters or symbols.

[0067] like Figure 4 As shown, the binary sequence "1111" represents the application of four consecutive light pulses with a 0.1s interval to the device. By controlling the number and interval of the light pulses, the resulting postsynaptic excitation current (EPSC) has a specific amplitude, such as... Figure 5 As shown, each optical pulse mode corresponds to a unique EPSC response. Therefore, by using the EPSC amplitude output by the device, the input binary sequence can be demodulated, and the corresponding text information can be restored and stored, realizing the neural synaptic information recognition and memory function based on optical pulse modulation.

[0068] This invention is not limited to the preferred embodiments described above. Anyone can derive other products in various forms under the guidance of this invention. However, regardless of any changes in shape or structure, any technical solution that is the same as or similar to this application falls within the protection scope of this invention.

Claims

1. A method for fabricating a gallium oxide photodetector based on reactive ion etching to enhance the synaptic effect, characterized in that, The method comprises the following specific steps: Step one: growing a gallium oxide layer on a substrate; Step two: performing a photoetching patterning process on the gallium oxide layer; Step three: etching the gallium oxide layer; boron trichloride generates boron dichloride cations under plasma excitation, which reacts with oxygen ions in the gallium oxide to form volatile products and thus form oxygen vacancies; argon ions act as a physical sputtering source to bombard and destroy the gallium-oxygen bond structure, causing oxygen atoms to separate from the lattice and thus form oxygen vacancies; Step four: performing photoetching on the etched gallium oxide layer to form a gallium oxide base, and depositing a laminated metal on the surface of the gallium oxide layer; the gallium oxide layer and the laminated metal are peeled off from the substrate to obtain an electrode; Step five: annealing the electrode to alloy it and form an ohmic contact.

2. The method of claim 1, wherein the method is characterized by: In step one, the gallium oxide layer can be grown by any one of metal organic chemical vapor deposition, pulsed laser deposition, and molecular beam epitaxy.

3. The method for fabricating a gallium oxide photodetector based on reactive ion etching to enhance the synaptic effect according to claim 1, characterized in that, In step three, when the gallium oxide layer is etched, the flow rate of boron trichloride is 25-35 sccm, the flow rate of argon is 5-15 sccm, the etching pressure is 0.5-1 Pa, the radio frequency power is 100 W, and the ICP power is 800 W.

4. The method of claim 1, wherein the method comprises: In step four, the laminated metal comprises, in sequence, a titanium metal layer, an aluminum metal layer, a nickel metal layer, and a gold metal layer.

5. The method of claim 1, wherein the method is characterized by: In step four, the laminated metal is formed on the surface of the gallium oxide base by magnetron sputtering, electron beam evaporation, or thermal evaporation.

6. The method of claim 1, wherein the method is characterized by: In step five, the electrode is annealed by using a rapid thermal annealing device or a tube-type annealing furnace; the annealing is performed in a nitrogen atmosphere, the annealing temperature is 470 DEG C, and the annealing time is 1 minute.

7. The method of claim 1, wherein the method is characterized by: The substrate is a sapphire substrate or a silicon substrate.

8. The method of claim 1, wherein the method is characterized by: Before the gallium oxide layer is grown on the substrate, the substrate is subjected to organic cleaning; specifically, the substrate is sequentially subjected to ultrasonic cleaning by using acetone, isopropyl alcohol, and deionized water, each for 5 minutes, and is dried by using a nitrogen gun after each cleaning; after the organic cleaning, the substrate is cleaned by using a piranha solution for 30 minutes to remove dangling bonds, surface states, and contaminants present on the surface of the substrate.

9. The method of claim 1, wherein the method comprises: The gallium oxide photoelectric detector is applied to information demodulation; letters or symbols are converted into binary sequences containing "0" or "1", "0" represents no light pulse in the corresponding time period, and "1" represents a light pulse in the corresponding time period; each binary sequence corresponds to a light pulse mode, and each light pulse mode has a specific number of light pulses and a specific light pulse interval time; By controlling the number of light pulses and the light pulse interval time, the gallium oxide photoelectric detector generates an excitatory postsynaptic current with a specific amplitude, and each light pulse mode corresponds to a unique current response; the input binary sequence is demodulated by the current response output by the gallium oxide photoelectric detector, and the corresponding letter or symbol information is restored and stored.

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