Gallium oxide-based fin-type solar-blind ultraviolet phototransistor and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor optoelectronic devices, in particular to a gallium oxide-based fin type solar-blind ultraviolet photoelectric transistor and a preparation method thereof. Comprising a substrate; the Ga2O3 thin film is arranged on the substrate; the periodic fin-type channel structure is located in the region of the Ga2O3 film and is formed by an etching process, the width of a single fin is the same as the interval between adjacent fins, and the height of the fins is equal to the thickness of the Ga2O3 film; the source electrode and the drain electrode are located at the two ends of the fin array of the periodic fin type channel structure respectively and form ohmic contact with the Ga2O3 thin film; the gate dielectric layer covers the surface of the periodic fin type channel structure; and the metal gate electrode covers the surface of the gate dielectric layer to form a surrounding type gate control structure. The method has the advantages that the short channel effect is effectively inhibited through the three-dimensional grid-control structure of the fin-type transistor, and extremely low dark current is kept while the submicron channel length is realized; localization and absorption of solar-blind ultraviolet light in a channel are remarkably enhanced, and quantum efficiency and photoelectric gain are improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor optoelectronic device technology, and in particular to a gallium oxide-based fin-type solar-blind ultraviolet phototransistor and its fabrication method. Background Technology

[0002] Solar-blind ultraviolet photodetectors exhibit selective response to ultraviolet light in the 200–280 nm wavelength range. Furthermore, solar radiation in this band is almost completely absorbed by the atmospheric ozone layer, resulting in virtually no background light interference in the natural environment, thus leading to extremely low background noise and false alarm rates. This unique advantage makes them promising for applications in key areas such as missile early warning, flame detection, ultraviolet communication, space exploration, and power system corona detection. In recent years, solar-blind ultraviolet detectors based on wide-bandgap semiconductor materials have become a research hotspot due to their advantages such as being all-solid-state, miniaturized, and requiring no additional filters.

[0003] Among numerous candidate materials, Ga2O3, with its direct bandgap of approximately 4.6–5.0 eV, precisely covers the solar-blind ultraviolet band, and possesses excellent thermal stability, chemical inertness, and radiation resistance, is considered one of the ideal materials for constructing high-performance solar-blind ultraviolet photodetectors. However, to achieve truly practical high-performance detectors, three core indicators must be met simultaneously: high photoelectric gain, low dark current, and fast response speed. Currently, Ga2O3-based solar-blind ultraviolet detectors mainly achieve photoelectric gain through three mechanisms: photoconductive gain, avalanche gain, and intrinsic transistor gain, corresponding to photoconductive devices, avalanche photodiodes (APDs), and phototransistors, respectively.

[0004] Photoconductive Ga2O3 devices are simple in structure and low in cost, and can achieve 10 2 ~10 3 While achieving photoconductive gain on the order of magnitude, these photodiodes generally suffer from severe persistent photoconductive effects, resulting in response times on the order of seconds. Furthermore, the lack of a built-in barrier leads to high dark current, making them unsuitable for high-speed detection. Avalanche photodiodes, although capable of achieving gains exceeding 10... 5 While Ga2O3-based phototransistors offer high gain and fast response (milliseconds), their current limitations stem from the difficulty of p-type doping in Ga2O3 materials. Existing devices often employ heterojunctions or Schottky structures, and interface defects result in dark currents generally exceeding 1 nA, limiting noise performance. In contrast, Ga2O3-based phototransistors, leveraging the intrinsic current amplification effect of transistors, have achieved gains as high as 10 nA. 5 The above photoelectric gain, combined with the ability to reduce dark current to the fA level (e.g., 27 fA) through gate voltage modulation, is significantly superior to the previous two types of devices, making it the mainstream research direction for high-gain, low-dark-current solar-blind detectors.

[0005] However, most existing Ga2O3 phototransistors employ traditional planar field-effect transistor structures, whose response speed is limited by the source-drain channel length—the longer the channel, the longer the transit time of photogenerated carriers, resulting in a slower response. Although some studies have shortened the channel to the micrometer scale, when the channel length is further reduced to submicrometer (<1 μm), the short-channel effect becomes significant. The drain electric field severely interferes with the gate's control over the channel, leading to pinch-off failure and a surge in leakage current, thus negating the advantage of low dark current. Therefore, further improving the response speed while maintaining extremely low dark current has become a key technological bottleneck for Ga2O3-based phototransistors. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a gallium oxide-based fin-type solar-blind ultraviolet phototransistor and its fabrication method.

[0007] The first objective of this invention is to provide a gallium oxide-based fin-type solar-blind ultraviolet phototransistor, comprising: Substrate; A Ga2O3 thin film disposed on a substrate; The periodic fin channel structure is located within the region of the Ga2O3 thin film and is formed by etching. The width of a single fin is the same as the spacing between adjacent fins, and the fin height is equal to the thickness of the Ga2O3 thin film. The source and drain are located at the two ends of the fin array of the periodic fin channel structure, respectively, and form ohmic contact with the Ga2O3 thin film; A gate dielectric layer covers the surface of the periodic fin channel structure; A metal gate electrode is placed on the surface of the gate dielectric layer to form a surrounding gate control structure.

[0008] Preferably, the periodic fin channel structure is etched by focused ion beam to form a fin array; wherein the width of a single fin and the interval between adjacent fins are both 100~300 nm, the fin length is 400~800 nm, and the number of fins is 10~30.

[0009] Preferably, the width of a single fin is 150 nm from the interval between adjacent fins, the fin length is 600 nm, and the number of fin rays is 25.

[0010] Preferably, the Ga2O3 film thickness is 200~500 nm; the substrate is a double-polished c-plane sapphire substrate.

[0011] Preferably, the gate dielectric layer is selected from at least one of Al2O3, SiO2, HfO2 and ZrO2; the source and the drain are selected from at least one of platinum, gold, titanium and aluminum, and are prepared by electron beam exposure and thermal evaporation deposition process.

[0012] Preferably, the thickness of the gate dielectric layer is 20~50 nm; the metal gate electrode is selected from platinum or gold, and the thickness is 30~80 nm.

[0013] Preferably, the Ga2O3 thin film has a thickness of 300 nm; the gate dielectric layer is selected from Al2O3 and has a thickness of 30 nm; the source and the drain are selected from platinum or gold; and the metal gate electrode has a thickness of 30 nm.

[0014] The second objective of this invention is to provide a method for fabricating a gallium oxide-based fin-type solar-blind ultraviolet phototransistor, specifically comprising the following steps: S1. Ga2O3 thin film is grown on a substrate by molecular beam epitaxy; S2. The Ga2O3 film is patterned by focused ion beam etching to form a periodic fin channel structure consisting of 10 to 30 parallel fin arrays; the sample is then annealed at 650 to 900 °C for 1 to 4 hours in an oxygen atmosphere. S3. Spin-coat photoresist on the surface and use electron beam exposure to define source and drain patterns at both ends of the periodic fin channel structure; form source and drain through thermal evaporation deposition and complete the fabrication through a lift-off process; S4. Spin-coat electron beam photoresist again, and define the gate dielectric layer coverage area on the surface of the periodic fin channel structure by electron beam exposure; deposit the gate dielectric layer using atomic layer deposition. S5. Metal is deposited on the surface of the gate dielectric layer by thermal evaporation, and the metal gate electrode is fabricated by a lift-off process.

[0015] Preferably, in step S1, the substrate is placed in a molecular beam epitaxy system, and a Ga2O3 thin film of 200-500 nm is grown at 600-900 °C in an oxygen atmosphere. Step S4 involves depositing a gate dielectric layer at 150°C.

[0016] Preferably, step S2 involves high-temperature annealing at 800°C for 2 hours in an oxygen atmosphere; step S4 involves depositing a gate dielectric layer at 130~180°C.

[0017] Compared with the prior art, the present invention can achieve the following beneficial effects: (1) The fin transistor structure is adopted. The three-dimensional gate wraps the channel in multiple ways, which significantly enhances the electrostatic control capability of the gate on the channel carriers. It effectively suppresses the short channel effect and the phenomenon of leakage-induced barrier reduction, so that the channel can still be effectively pinched off when the channel length is shortened to the submicron level. Thus, while maintaining extremely low dark current, the transit time of photogenerated carriers is greatly shortened, and the device response speed is improved. (2) By periodically arranging multiple fin structures to form a one-dimensional photonic crystal, its photonic bandgap characteristics and local field enhancement effect can be utilized to efficiently localize and confine almost all incident solar-blind ultraviolet light within the active channel region, significantly improving light absorption efficiency and quantum yield, thereby achieving high photoelectric gain.

[0018] In summary, this invention, by fabricating an innovative gallium oxide phototransistor structure, integrates a fin transistor and a one-dimensional photonic crystal into a Ga2O3 solar-blind ultraviolet detector for the first time. This successfully overcomes the constraints of traditional planar structures on dark current and response speed, providing a practical technical path for realizing a next-generation solar-blind ultraviolet photodetector with high gain, low noise, and high-speed response. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a gallium oxide-based fin-type solar-blind ultraviolet phototransistor provided in an embodiment of the present invention.

[0020] Figure 2 This is a cross-sectional structural schematic diagram of a gallium oxide-based fin-type solar-blind ultraviolet phototransistor provided according to an embodiment of the present invention.

[0021] Figure 3 This is the It curve of a gallium oxide-based fin-type solar-blind ultraviolet phototransistor provided according to an embodiment of the present invention.

[0022] Figure 4 This is the spectral response curve of a gallium oxide-based fin-type solar-blind ultraviolet phototransistor provided according to an embodiment of the present invention.

[0023] Figure 5 This is the transient photoresponse curve of a gallium oxide-based fin-type solar-blind ultraviolet phototransistor provided according to an embodiment of the present invention.

[0024] Figure label: 1. Substrate; 2. Ga2O3 thin film; 201. Periodic fin-type channel structure; 4. Source pole; 5. Drain electrode; 6. Gate dielectric layer; 7. Metal gate electrode. Detailed Implementation

[0025] In the following description, embodiments of the invention will be described with reference to the accompanying drawings. In the description below, the same modules are denoted by the same reference numerals. Where the same reference numerals are used, their names and functions are also the same. Therefore, their detailed description will not be repeated.

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0027] See Figures 1-2 This invention provides a gallium oxide-based fin-type solar-blind ultraviolet phototransistor, comprising: Substrate 1 serves as the basic support layer for the device; Ga2O3 thin film 2 is disposed on substrate 1; The periodic fin channel structure 201 is located within the region of the Ga2O3 thin film 2 and is formed into a fin array by an etching process; the periodic fin channel structure 201 constitutes a one-dimensional photonic crystal, providing a structural basis for the photoelectric response of the device; Source 4 and drain 5 are located at the two ends of the fin array of the periodic fin channel structure 201, and form ohmic contact with the Ga2O3 thin film 2 to realize the injection and collection of charge carriers. A gate dielectric layer 6 covers the surface of the periodic fin channel structure 201; The metal gate electrode 7 covers the surface of the gate dielectric layer 6, forming a surrounding gate control structure to achieve effective regulation of the channel current.

[0028] Specifically, substrate 1 is a double-polished c-plane sapphire substrate; Ga2O3 thin film 2 is formed on substrate 1 by epitaxial growth process; the thickness of Ga2O3 thin film 2 is 200~500 nm. In a specific embodiment, the thickness of the Ga2O3 thin film 2 is 300 nm; The periodic fin channel structure 201 is etched by focused ion beam to form a fin array; wherein the width of a single fin and the interval between adjacent fins are both 100~300 nm, the fin length is 400~800 nm, the number of fins is 10~30, and the fin height is equal to the thickness of the Ga2O3 film. In a specific embodiment, the width of a single fin and the interval between adjacent fins is 150 nm, the fin length is 600 nm, and the number of fin rays is 25. Specifically, source 4 and drain 5 are selected from at least one of platinum (Pt), gold (Au), titanium (Ti), and aluminum (Al); preferably platinum (Pt) or gold (Au), and are prepared by electron beam exposure and thermal evaporation deposition process; Specifically, the gate dielectric layer 6 is selected from at least one of Al2O3, SiO2, HfO2 and ZrO2, and the thickness of the gate dielectric layer 6 is 20~50 nm; In a specific embodiment, the gate dielectric layer 6 is an Al2O3 gate dielectric layer with a thickness of 30 nm; The metal gate electrode 7 is made of platinum (Pt) or gold (Au); it is prepared by depositing the gate dielectric layer 6 using an atomic layer deposition (ALD) system followed by thermal evaporation deposition; the thickness of the metal gate electrode 7 is 30~80 nm. In a specific embodiment, the thickness of the metal gate electrode 7 is 30 nm.

[0029] A method for fabricating a gallium oxide-based fin-type solar-blind ultraviolet phototransistor is also provided, which specifically includes the following steps: S1. Ga2O3 thin films are grown on a substrate by molecular beam epitaxy (MBE); Specifically, the substrate is placed in a molecular beam epitaxy system, and a Ga2O3 thin film of 200-500 nm is grown at 600-900 °C in an oxygen atmosphere; S2. Fabrication of periodic finned channel structures: The Ga2O3 film was patterned using a focused ion beam (FIB) system to form an array of 10-30 parallel fins. The width of each fin and the spacing between adjacent fins were 100-300 nm, the fin length was 400-800 nm, and the fin height was equal to the thickness of the Ga2O3 film. The sample was then placed in a tube furnace and annealed at 650-900 °C for 1-4 hours in an oxygen atmosphere. Specifically, the etching parameters are set as follows: Ga⁺ ion beam energy is 30 kV, and beam current is 10 pA; The etching process forms a 25-fin array, each fin being 150 nm wide, with a spacing of 150 nm between adjacent fins and a length of 600 nm. This periodic fin-channel structure constitutes a one-dimensional photonic crystal with a photonic bandgap covering the solar-blind ultraviolet band (200~280 nm). The sample was annealed at 800℃ for 2 hours.

[0030] S3. Fabrication of source and drain electrodes: Spin-coat electron beam photoresist onto the sample surface and pre-bake it on a hot plate; define source and drain electrode patterns at both ends of the fin array using an electron beam exposure system; after development, form source and drain electrodes by thermal evaporation deposition and complete the fabrication by a lift-off process; Specifically, the process involves using an acetone stripping process, ultrasonically cleaning in acetone for 5 minutes, followed by ultrasonic cleaning in ethanol and deionized water for 5 minutes each, and finally drying with high-purity nitrogen. 50 nm of Pt was thermally evaporated and deposited as the source and drain.

[0031] S4. Fabrication of the gate dielectric layer: Spin-coating electron beam photoresist again, defining the gate dielectric layer coverage area on the surface of the periodic fin channel structure using an electron beam exposure system; fabricating the gate dielectric layer using atomic layer deposition; Specifically, the sample was transferred to an atomic layer deposition (ALD) system, where a 30 nm thick Al2O3 gate dielectric layer was deposited at 150°C.

[0032] S5. Fabrication of metal gate electrode: Metal is deposited on the surface of the gate dielectric layer by thermal evaporation, and the metal gate electrode is fabricated by a lift-off process, finally obtaining a complete gallium oxide-based fin solar-blind ultraviolet phototransistor device; Specifically, 30 nm of Pt is deposited on the surface of the Al2O3 gate dielectric layer as a metal gate electrode, and the metal gate electrode is fabricated by a lift-off process.

[0033] Example 1 like Figures 1-2 As shown, this embodiment provides a gallium oxide-based fin-type solar-blind ultraviolet phototransistor, including: substrate 1 is a double-polished c-plane sapphire substrate; The Ga2O3 thin film 2 disposed on the substrate 1 is formed by epitaxial growth process and has a thickness of 300 nm. A periodic fin channel structure 201 is located within the region of the Ga2O3 thin film 2 and is formed into a fin array by a focused ion beam etching process; the periodic fin channel structure 201 constitutes a one-dimensional photonic crystal; the width of a single fin and the spacing between adjacent fins are 150 nm, the fin length is 600 nm, and the number of fins is 25. Source 4 and drain 5 are located at the two ends of the fin array of the periodic fin channel structure 201, and form ohmic contact with the Ga2O3 thin film 2 to realize the injection and collection of charge carriers; both source 4 and drain 5 are made of platinum and are prepared by electron beam exposure and thermal evaporation deposition process. Gate dielectric layer 6 covers the surface of periodic fin channel structure 201; gate dielectric layer 6 is an Al2O3 gate dielectric layer with a thickness of 30 nm; The metal gate electrode 7 is covered on the surface of the gate dielectric layer 6 to form a surrounding gate control structure, thereby achieving effective control of the channel current. The metal gate electrode 7 is made of platinum and is prepared by atomic layer deposition of the gate dielectric layer 6 followed by thermal evaporation deposition. In traditional planar transistors, the gate is only above the channel. However, the all-around metal gate electrode 7 of this invention surrounds the channel and applies electric fields from multiple directions, which significantly enhances the gate control capability. It can effectively suppress the short-channel effect, improve the switching speed, reduce leakage current, and synergistically improve the photoelectric conversion efficiency.

[0034] The fabrication method of gallium oxide-based fin-type solar-blind ultraviolet phototransistor specifically includes the following steps: S1. Epitaxial growth of Ga2O3 thin film: A double-polished c-plane sapphire substrate was placed in a molecular beam epitaxy (MBE) system, and a high-quality Ga2O3 thin film was grown at 750 °C in an oxygen atmosphere, with the film thickness controlled to be 300 nm.

[0035] S2. Fabrication of a periodic fin channel structure: The Ga2O3 thin film was patterned using a focused ion beam (FIB) system; the etching parameters were set as follows: Ga⁺ ion beam energy of 30 kV and beam current of 10 pA; 25 parallel fin arrays were formed, each fin with a width of 150 nm, an adjacent fin spacing of 150 nm, a fin length (i.e., the channel length in the source-drain direction) of 600 nm, and a fin height equal to the Ga2O3 thin film thickness (300 nm); the fin array of this periodic fin channel structure constitutes a one-dimensional photonic crystal, whose photonic bandgap covers the solar-blind ultraviolet band (200~280 nm); the sample was then placed in a tube furnace and annealed at 800℃ for 2 hours in an oxygen atmosphere.

[0036] S3. Preparation of source and drain electrodes: Spin-coat electron beam photoresist on the sample surface and pre-bake on a hot plate; define source and drain electrode patterns at both ends of the fin array using an electron beam exposure system; after development, place the sample into a thermal evaporation deposition system and deposit 50 nm Pt as source and drain electrodes; use an acetone stripping process, ultrasonically clean in acetone for 5 minutes, then ultrasonically clean in ethanol and deionized water for 5 minutes each, and finally dry with high-purity nitrogen gas.

[0037] S4. Preparation of gate dielectric layer: Spin-coat electron beam photoresist again, and define the gate dielectric layer coverage area on the surface of the periodic fin channel structure using an electron beam exposure system; transfer the sample to an atomic layer deposition (ALD) system and deposit a 30 nm thick Al2O3 gate dielectric layer at 150°C; S5. Fabrication of metal gate electrode: 30 nm Pt is deposited on the surface of Al2O3 gate dielectric layer as metal gate electrode, and the metal gate electrode is fabricated by a lift-off process to finally obtain a complete gallium oxide-based fin solar-blind ultraviolet phototransistor device.

[0038] During device testing, the test light source was incident from one side of the double-polished sapphire substrate. The device performance test results are as follows: Figure 3 The current-time (It) response curves of the gallium oxide phototransistor prepared for this embodiment of the invention under dark conditions and 255 nm ultraviolet light illumination. Test conditions: V DS =500 mV, V GS =400 mV. The results show that the device has good stability, with a dark current as low as approximately 10⁻²⁰ fA.

[0039] Figure 4 This is the spectral response curve of the device. The test was conducted at V... DS =500 mV, V GSThe experiments were conducted at 400 mV. The results show that the device exhibits a significant response in the 200-280 nm wavelength range, with a peak response at approximately 255 nm. Its solar-blind UV / visible-blind UV suppression ratio (255 nm / 365 nm) exceeds six orders of magnitude, demonstrating excellent solar-blind characteristics. Furthermore, the device's peak responsivity is approximately 3.5 × 10⁻⁶. 4 A / W, gain over 10 5 .

[0040] Figure 5 The transient optical response curve (response / recovery time test) of the device is shown. Under 255 nm pulsed ultraviolet light irradiation, the device fall time (90%~10%) is about 6 μs, indicating that the device has an extremely fast response speed.

[0041] In summary, the gallium oxide-based fin-type solar-blind ultraviolet phototransistor with a one-dimensional photonic crystal structure fabricated in this embodiment successfully achieved high photoelectric gain (>10). 5 The synergistic optimization of extremely low dark current (~fA level) and fast response verifies the feasibility and advancement of the technical solution of this invention.

[0042] It should be noted that the materials, dimensional parameters, and process conditions used in the above embodiments can be adjusted according to actual needs. For example, the source / drain / gate electrode metals can be replaced with Au or other high work function metals; the gate dielectric layer can be replaced with HfO2, SiO2, etc. instead of Al2O3; the period, width, and height of the fin structure can also be optimized in the range of 100~300 nm to match different wavelengths of solar-blind ultraviolet light.

[0043] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0044] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A gallium oxide-based fin-type solar-blind ultraviolet phototransistor, characterized in that: include: Substrate; A Ga2O3 thin film disposed on a substrate; The periodic fin channel structure is located within the region of the Ga2O3 thin film and is formed by etching. The width of a single fin is the same as the spacing between adjacent fins, and the fin height is equal to the thickness of the Ga2O3 thin film. The source and drain are located at the two ends of the fin array of the periodic fin channel structure, respectively, and form ohmic contact with the Ga2O3 thin film; A gate dielectric layer covers the surface of the periodic fin channel structure; A metal gate electrode is placed on the surface of the gate dielectric layer to form a surrounding gate control structure.

2. The gallium oxide-based fin-type solar-blind ultraviolet phototransistor according to claim 1, characterized in that: The periodic fin channel structure is etched by a focused ion beam to form a fin array; wherein the width of a single fin and the interval between adjacent fins are both 100~300 nm, the fin length is 400~800 nm, and the number of fins is 10~30.

3. The gallium oxide-based fin-type solar-blind ultraviolet phototransistor according to claim 2, characterized in that: The width of a single fin is 150 nm from the interval between adjacent fins, the fin length is 600 nm, and the number of fin rays is 25.

4. The gallium oxide-based fin-type solar-blind ultraviolet phototransistor according to claim 1, characterized in that: The Ga2O3 thin film has a thickness of 200~500 nm; the substrate is a double-polished c-plane sapphire substrate.

5. A gallium oxide-based fin-type solar-blind ultraviolet phototransistor according to claim 1, characterized in that: The gate dielectric layer is selected from at least one of Al2O3, SiO2, HfO2 and ZrO2; the source and the drain are selected from at least one of platinum, gold, titanium and aluminum, and are prepared by electron beam exposure and thermal evaporation deposition process.

6. A gallium oxide-based fin-type solar-blind ultraviolet phototransistor according to claim 1, characterized in that: The thickness of the gate dielectric layer is 20~50 nm; the metal gate electrode is selected from platinum or gold and has a thickness of 30~80 nm.

7. A gallium oxide-based fin-type solar-blind ultraviolet phototransistor according to claim 1, characterized in that: The Ga2O3 thin film has a thickness of 300 nm; the gate dielectric layer is selected from Al2O3 and has a thickness of 30 nm; the source and the drain are selected from platinum or gold; the metal gate electrode has a thickness of 30 nm.

8. The method for fabricating a gallium oxide-based fin-type solar-blind ultraviolet phototransistor according to claim 1, characterized in that: Specifically, the steps include the following: S1. Ga2O3 thin film is grown on a substrate by molecular beam epitaxy; S2. The Ga2O3 film is patterned by focused ion beam etching to form a periodic fin channel structure consisting of 10 to 30 parallel fin arrays; the sample is then annealed at 650 to 900 °C for 1 to 4 hours in an oxygen atmosphere. S3. Spin-coat photoresist on the surface and use electron beam exposure to define source and drain patterns at both ends of the periodic fin channel structure; form source and drain through thermal evaporation deposition and complete the fabrication through a lift-off process; S4. Spin-coat electron beam photoresist again, and define the gate dielectric layer coverage area on the surface of the periodic fin channel structure by electron beam exposure; deposit the gate dielectric layer using atomic layer deposition. S5. Metal is deposited on the surface of the gate dielectric layer by thermal evaporation, and the metal gate electrode is fabricated by a lift-off process.

9. The method for fabricating a gallium oxide-based fin-type solar-blind ultraviolet phototransistor according to claim 8, characterized in that: In step S1, the substrate is placed in a molecular beam epitaxy system, and a Ga2O3 thin film of 200-500 nm is grown at 600-900 °C in an oxygen atmosphere. Step S4 involves depositing a gate dielectric layer at 150°C.

10. The method for fabricating a gallium oxide-based fin-type solar-blind ultraviolet phototransistor according to claim 8, characterized in that: Step S2 involves high-temperature annealing at 800°C for 2 hours in an oxygen atmosphere; Step S4 involves depositing a gate dielectric layer at 130~180°C.

Images