Gallium oxide thin film based on gallium buffer layer and preparation method and application thereof

Abstract

The application relates to a gallium oxide film based on a gallium buffer layer and a preparation method and application thereof. The preparation method adopts an electron beam evaporation method, a gallium metal layer is prepared on a substrate, oxidation annealing is carried out on the gallium metal layer in an air atmosphere to obtain a gallium buffer layer, and finally a high-performance gallium oxide film is prepared on the surface of the gallium buffer layer by adopting a magnetron sputtering method. Compared with the prior art, the application has the advantages of simple operation, low cost, remarkable effect and the like. The gallium oxide film obtained by the application can be better applied in the fields of ultraviolet detection, light-emitting devices, solar cells and the like.

Description

Technical Field

[0001] This invention relates to the field of semiconductor material manufacturing technology, and in particular to a gallium oxide thin film based on a gallium buffer layer, its preparation method and application. Background Technology

[0002] Gallium oxide (Ga2O3) is a third-generation semiconductor material. Third-generation semiconductors have large band gaps, high breakdown strength, and strong radiation resistance, making them naturally suitable for fabricating high-voltage, high-frequency, and high-power semiconductor devices. Compared to other third-generation semiconductors such as silicon carbide (SiC) (Eg = 3.3 eV) and gallium nitride (GaN) (Eg = 3.4 eV), Ga2O3 has a larger band gap (Eg = 4.9 eV) and a breakdown voltage (8 MV / cm), which is more than 20 times that of silicon (Si) and more than twice that of SiC and GaN. Furthermore, Ga2O3 has a high Baliga value of 3214.1, which is beneficial for the fabrication of high-power, high-density integrated devices. Ga2O3 is a direct bandgap semiconductor material. Its wide bandgap gives it high transmittance in the visible light region, exceeding 80%, and excellent absorption performance in the ultraviolet (UV) band, especially in the solar-blind UV region below 280 nm, with an absorption edge around 250 nm. Therefore, it is frequently used to fabricate UV photodetectors, field-effect transistors (FETs), and Schottky diodes. Thus, Ga2O3 has significant application potential in defense, aerospace, microwave communications, and rail transportation.

[0003] The performance of devices such as ultraviolet photodetectors and field-effect transistors based on Ga2O3 depends on the quality of the Ga2O3 thin film itself. Therefore, obtaining high-performance Ga2O3 thin films is one of the keys to device applications. However, there is a significant lattice mismatch and difference in thermal expansion coefficients between Ga2O3 and common substrate materials (such as silicon and quartz), leading to a decrease in the quality of gallium oxide thin films grown directly on these substrates. Patent publication number CN107785241B discloses a method for preparing β-gallium oxide thin films on silicon substrates, in which a β-gallium oxide nanopillar array is grown on the silicon substrate as a buffer layer, and a β-gallium oxide thin film is prepared on the β-gallium oxide nanopillar array as the buffer layer. However, this method is time-consuming, has a long cycle, and involves cumbersome steps, requiring multiple annealing processes at high temperatures, and also involves multiple heating processes, which pose certain risks. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a gallium oxide thin film based on a gallium buffer layer, its preparation method, and its applications. Using electron beam evaporation and magnetron sputtering, and by selecting appropriate buffer layer annealing temperatures and thicknesses, high-performance gallium oxide thin films can be prepared. The process is simple, low-cost, and yields significant results, enabling better applications in ultraviolet detection, light-emitting devices, and solar cells.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] This invention provides a method for preparing a gallium oxide thin film based on a gallium buffer layer, comprising the following steps:

[0007] S1. Substrate treatment: The substrate is ultrasonically cleaned with acetone, methanol and deionized water in sequence, and then dried with high-purity nitrogen to obtain a clean and dry substrate.

[0008] S2. Gallium metal layer preparation: Gallium metal layer is prepared on the clean and dry substrate obtained in step S1 by electron beam evaporation.

[0009] S3. Post-annealing treatment: The substrate and gallium metal layer obtained in step S2 are subjected to post-annealing treatment. After annealing, the substrate is cooled to prepare a gallium buffer layer on the substrate.

[0010] S4. Gallium buffer layer cleaning: The gallium buffer layer obtained in step S3 is ultrasonically cleaned with acetone, methanol and deionized water in sequence, and then dried with high-purity nitrogen to obtain a clean and dry gallium buffer layer.

[0011] S5. Gallium oxide thin film preparation: Gallium oxide ceramic target is selected as the target material, and gallium oxide thin film is prepared on the clean and dry gallium buffer layer obtained in step S4 by magnetron sputtering.

[0012] Furthermore, in step S1, the substrate material includes inorganic materials or semiconductor materials.

[0013] Furthermore, in step S1, the substrate material is quartz.

[0014] Furthermore, in step S1, the ultrasonic cleaning time is 5 to 30 minutes to remove impurities and organic matter from the substrate surface.

[0015] Furthermore, in step S2, the specific operation process of gallium deposition by electron beam evaporation is as follows: the clean substrate obtained in step S1 is sent into the electron beam evaporation chamber, the metal to be deposited is gallium, and the process parameters are set to gallium process and the corresponding film thickness is set; the power of the electron beam equipment is turned on, and after preheating is completed, the power is increased at a rate of 2% to 10% per minute, and the temperature is maintained for 10 to 60 seconds, waiting for the beam to appear and adjusting the spot to be located inside the crucible without contacting the crucible wall; after the power reaches 20% to 60%, the increase rate is maintained at 1% to 5% per minute until the film deposition rate is reached. The process involves formal vapor deposition, after which a gallium metal layer is prepared on the substrate.

[0016] Furthermore, in step S2, the thickness of the prepared gallium metal layer is 10–80 nm.

[0017] Furthermore, in step S2, the thickness of the prepared gallium metal layer is 20–80 nm.

[0018] Furthermore, in step S3, the annealing temperature is 400–800°C, the annealing time is 30–120 min, and the cooling temperature is room temperature.

[0019] Furthermore, in step S3, the annealing temperature is 500–700°C.

[0020] Furthermore, in step S3, the temperature is increased at a rate ≥6℃ / min, held for 40–80 min, and then cooled.

[0021] Furthermore, in step S4, the ultrasonic cleaning time is 5 to 30 minutes in order to remove impurities generated in the gallium buffer layer during the annealing process.

[0022] Furthermore, in step S5, the gallium oxide ceramic target is a high-purity gallium oxide ceramic target with a purity of 99.99%.

[0023] Furthermore, in step S5, the specific operation process of the magnetron sputtering method is as follows: the gallium buffer layer and substrate obtained in step S4 are placed on the sample stage. After the sputtering chamber is evacuated, the substrate temperature is raised to 300-600℃. After the temperature stabilizes, argon gas with a flow rate of 15-30 sccm is introduced, and the vacuum degree of the chamber is adjusted to 5-7 Pa. The sputtering pressure and sputtering power are set to 0.4-0.5 Pa and 50-80 W, respectively. The sample tray rotation speed is ≤5 rad / min. After pre-sputtering for 10-30 min, the baffle is opened to start the formal sputtering. After the sputtering is completed, a gallium oxide thin film is prepared on the gallium buffer layer.

[0024] Furthermore, in step S5, the thickness of the prepared gallium oxide film is 100–150 nm.

[0025] The present invention also provides a gallium oxide thin film based on a gallium buffer layer, which is prepared by the above-described preparation method.

[0026] The present invention also provides an application of gallium oxide thin film based on gallium buffer layer in ultraviolet detection, light-emitting devices or solar cells.

[0027] Compared with the prior art, the present invention has the following obvious and prominent substantive features and significant advantages:

[0028] (1) This invention uses magnetron sputtering to prepare gallium oxide thin films, which is a physical vapor deposition method. An electric field is formed with the substrate as the positive electrode and the target as the negative electrode. Argon gas (Ar) undergoes glow discharge in this electric field, ionizing into Ar ions and electrons (e). The Ar ions move towards the target under the influence of the electric field and accelerate to collide with it, allowing target atoms to escape from the surface. These escaped target atoms then deposit on the substrate surface to form a thin film. The entire process only requires commercially available target materials and the correct experimental parameters to prepare the thin film. The equipment can also monitor the film thickness. Therefore, compared to other growth processes, magnetron sputtering has the advantages of simple operation, low cost, large-area preparation capability, and high feasibility for batch growth.

[0029] (2) The present invention performs high-temperature oxidation annealing of gallium metal layer at a temperature below 900°C in air atmosphere to obtain high-quality gallium buffer layer after oxidation and transformation to β phase. At the same time, high-quality β-gallium oxide film can be prepared on gallium buffer layer by increasing substrate temperature, without the need to perform high-temperature annealing at 900°C after gallium oxide film preparation.

[0030] (3) The present invention is based on the growth of gallium oxide thin film by gallium buffer layer. Since silicon (Si) in quartz substrate and gallium (Ga) in gallium oxide thin film are not elements in the same group in the periodic table, and gallium buffer layer and thin film to be prepared both belong to gallium oxide, it can not only reduce lattice mismatch, but also transfer and release thermal stress caused by stress and huge difference in thermal expansion coefficient during growth, thereby improving lattice defects. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the preparation method shown in Example 1;

[0032] Figure 2 This is a schematic diagram of the gallium metal layer fabrication apparatus shown in Example 1;

[0033] Figure 3 This is a schematic diagram of the gallium oxide thin film preparation apparatus shown in Example 1;

[0034] Figure 4Current-voltage (IV) plots of a solar-blind ultraviolet detector fabricated from gallium oxide thin films, (a) without gallium buffer layer, (b) annealing temperature of 500 °C, (c) annealing temperature of 600 °C, (d) annealing temperature of 700 °C;

[0035] Figure 5 IV images of solar-blind ultraviolet detectors fabricated on gallium oxide thin films prepared on gallium buffer layers at different annealing temperatures;

[0036] Figure 6 IV images of a solar-blind ultraviolet detector fabricated from gallium oxide thin films: (a) without gallium buffer layer, (b) gallium buffer layer with a thickness of 20 nm, (c) gallium buffer layer with a thickness of 50 nm, and (d) gallium buffer layer with a thickness of 80 nm. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments. All other embodiments obtained by those skilled in the art based on the given embodiments without creative effort are within the scope of protection of this application.

[0038] Unless otherwise specified, the reagents, methods, instruments and equipment used in this invention are conventional reagents, methods, instruments and equipment in the art.

[0039] Example 1

[0040] A method for preparing a gallium oxide thin film based on a gallium buffer layer includes the following steps:

[0041] S1, Substrate processing:

[0042] A quartz substrate with dimensions of 19.5 mm × 19.5 mm and a thickness of 1 mm was selected. The substrate was ultrasonically treated in acetone, methanol, and deionized water for 10 min each, and then dried with high-purity nitrogen to obtain a clean and dry substrate.

[0043] S2, Gallium metal layer fabrication:

[0044] The clean and dry substrate obtained in step S1 is placed into the electron beam evaporation chamber. The metal to be deposited is gallium, and the process parameters are set to gallium and the film thickness is set. The electron beam equipment is powered on, and after preheating is complete, the power is increased at a rate of 5% per minute, and the temperature is maintained for 30 seconds. The beam current is then observed, and the beam spot is adjusted to be located inside the crucible without contacting the crucible wall. After the power reaches 30%, the increase rate is maintained at 1% per minute until the film deposition rate reaches [a certain value]. The formal evaporation process was carried out, and after the evaporation was completed, a gallium metal layer with a thickness of 20 nm was prepared on the substrate.

[0045] S3. Post-annealing treatment:

[0046] The substrate and gallium metal layer obtained in step S2 are placed in a rapid annealing furnace for annealing post-treatment; the annealing temperature is 500℃ and the annealing time is 60min. After annealing, the gallium film is cooled to room temperature and then removed to obtain a gallium buffer layer with a uniform and dense structure.

[0047] S4, Buffer layer cleaning

[0048] To remove impurities generated in the gallium buffer layer during the annealing process, the gallium buffer layer obtained in step S3 was ultrasonically cleaned for 10 minutes with deionized water, acetone, methanol, and deionized water, respectively, and then dried with high-purity nitrogen to obtain a clean and dry gallium buffer layer.

[0049] S5, Gallium oxide thin film preparation

[0050] The target material was selected as a high-purity gallium oxide ceramic target with a purity of 99.99%. The gallium buffer layer and substrate obtained in step S4 were placed on the sample stage. After the sputtering chamber was evacuated, the substrate temperature was raised to 400℃. After the temperature stabilized, argon gas with a flow rate of 25 sccm was introduced, and the vacuum degree of the chamber was adjusted to 5 Pa. The sputtering pressure and sputtering power were set to 0.4 Pa and 60 W, respectively, and the sample tray rotation speed was ≤5 rad / min. After pre-sputtering for 30 min, the baffle was opened to start the formal sputtering. After the sputtering was completed, a gallium oxide thin film with a thickness of 100 nm was prepared on the gallium buffer layer.

[0051] Example 2

[0052] A method for preparing a gallium oxide thin film based on a gallium buffer layer includes the following steps:

[0053] S1, Substrate processing:

[0054] A quartz substrate with dimensions of 19.5 mm × 19.5 mm and a thickness of 1 mm was selected. The substrate was ultrasonically treated in acetone, methanol, and deionized water for 10 min each, and then dried with high-purity nitrogen to obtain a clean and dry substrate.

[0055] S2, Gallium metal layer fabrication:

[0056] The clean and dry substrate obtained in step S1 is placed into the electron beam evaporation chamber. The metal to be deposited is gallium, and the process parameters are set to gallium and the film thickness is set. The electron beam equipment is powered on, and after preheating is complete, the power is increased at a rate of 5% per minute, and the temperature is maintained for 30 seconds. The beam current is then observed, and the beam spot is adjusted to be located inside the crucible without contacting the crucible wall. After the power reaches 30%, the increase rate is maintained at 1% per minute until the film deposition rate reaches [a certain value]. The process involves formal evaporation, and after evaporation, a gallium metal layer with a thickness of 50 nm is prepared on the substrate.

[0057] S3. Post-annealing treatment:

[0058] The substrate and gallium metal layer obtained in step S2 are placed in a rapid annealing furnace for annealing post-treatment; the annealing temperature is 500℃ and the annealing time is 60min. After annealing, the gallium film is cooled to room temperature and then removed to obtain a gallium buffer layer with a uniform and dense structure.

[0059] S4, Buffer layer cleaning

[0060] To remove impurities generated in the gallium buffer layer during the annealing process, the gallium buffer layer obtained in step S3 was ultrasonically cleaned for 10 minutes with deionized water, acetone, methanol, and deionized water, respectively, and then dried with high-purity nitrogen to obtain a clean and dry gallium buffer layer.

[0061] S5, Gallium oxide thin film preparation

[0062] The target material was selected as a high-purity gallium oxide ceramic target with a purity of 99.99%. The gallium buffer layer and substrate obtained in step S4 were placed on the sample stage. After the sputtering chamber was evacuated, the substrate temperature was raised to 400℃. After the temperature stabilized, argon gas with a flow rate of 25 sccm was introduced, and the vacuum degree of the chamber was adjusted to 5 Pa. The sputtering pressure and sputtering power were set to 0.4 Pa and 60 W, respectively, and the sample tray rotation speed was ≤5 rad / min. After pre-sputtering for 30 min, the baffle was opened to start the formal sputtering. After the sputtering was completed, a gallium oxide thin film with a thickness of 100 nm was prepared on the gallium buffer layer.

[0063] Example 3

[0064] A method for preparing gallium oxide thin films based on gallium buffer layers, such as... Figure 1 As shown, it includes the following steps:

[0065] S1, Substrate processing:

[0066] A quartz substrate with dimensions of 19.5 mm × 19.5 mm and a thickness of 1 mm was selected. The substrate was ultrasonically treated in acetone, methanol, and deionized water for 10 min each, and then dried with high-purity nitrogen to obtain a clean and dry substrate.

[0067] S2, Gallium metal layer fabrication:

[0068] like Figure 2As shown, the clean and dry substrate obtained in step S1 is placed into the electron beam evaporation chamber. The metal to be deposited is gallium, and the process parameters are set to gallium and the film thickness is set. The electron beam equipment power is turned on, and after preheating is completed, the power is increased at a rate of 5% per minute, and the temperature is maintained for 30 seconds. The beam current is then observed, and the beam spot is adjusted to be located inside the crucible without contacting the crucible wall. After the power reaches 30%, the increase rate is maintained at 1% per minute until the film deposition rate reaches [value missing]. The process involves formal evaporation, and after evaporation, a gallium metal layer with a thickness of 80 nm is prepared on the substrate.

[0069] S3. Post-annealing treatment:

[0070] The substrate and gallium metal layer obtained in step S2 are placed in a rapid annealing furnace for annealing post-treatment; the annealing temperature is 500℃ and the annealing time is 60min. After annealing, the gallium film is cooled to room temperature and then removed to obtain a gallium buffer layer with a uniform and dense structure.

[0071] S4, Buffer layer cleaning

[0072] To remove impurities generated in the gallium buffer layer during the annealing process, the gallium buffer layer obtained in step S3 was ultrasonically cleaned for 10 minutes with deionized water, acetone, methanol, and deionized water, respectively, and then dried with high-purity nitrogen to obtain a clean and dry gallium buffer layer.

[0073] S5, Gallium oxide thin film preparation

[0074] The target material was selected as a high-purity gallium oxide ceramic target with a purity of 99.99%, such as... Figure 3 As shown, the gallium buffer layer and substrate obtained in step S4 are placed on the sample stage. After the sputtering chamber is evacuated, the substrate temperature is raised to 400℃. After the temperature stabilizes, argon gas with a flow rate of 25 sccm is introduced, and the chamber vacuum degree is adjusted to 5 Pa. The sputtering pressure and sputtering power are set to 0.4 Pa and 60 W, respectively, and the sample tray rotation speed is ≤5 rad / min. After pre-sputtering for 30 min, the baffle is opened to start the formal sputtering. After the sputtering is completed, a gallium oxide thin film with a thickness of 100 nm is prepared on the gallium buffer layer.

[0075] Example 4

[0076] A method for preparing a gallium oxide thin film based on a gallium buffer layer includes the following steps:

[0077] S1, Substrate processing:

[0078] A quartz substrate with dimensions of 19.5 mm × 19.5 mm and a thickness of 1 mm was selected. The substrate was ultrasonically treated in acetone, methanol, and deionized water for 10 min each, and then dried with high-purity nitrogen to obtain a clean and dry substrate.

[0079] S2, Gallium metal layer fabrication:

[0080] The clean and dry substrate obtained in step S1 is placed into the electron beam evaporation chamber. The metal to be deposited is gallium, and the process parameters are set to gallium and the film thickness is set. The electron beam equipment is powered on, and after preheating is complete, the power is increased at a rate of 5% per minute, and the temperature is maintained for 30 seconds. The beam current is then observed, and the beam spot is adjusted to be located inside the crucible without contacting the crucible wall. After the power reaches 30%, the increase rate is maintained at 1% per minute until the film deposition rate reaches [a certain value]. The formal evaporation process was carried out, and after the evaporation was completed, a gallium metal layer with a thickness of 20 nm was prepared on the substrate.

[0081] S3. Post-annealing treatment:

[0082] The substrate and gallium metal layer obtained in step S2 are placed in a rapid annealing furnace for annealing post-treatment; the annealing temperature is 600℃ and the annealing time is 60min. After annealing, the gallium film is cooled to room temperature and then removed to obtain a gallium buffer layer with a uniform and dense structure.

[0083] S4, Buffer layer cleaning

[0084] To remove impurities generated in the gallium buffer layer during the annealing process, the gallium buffer layer obtained in step S3 was ultrasonically cleaned for 10 minutes with deionized water, acetone, methanol, and deionized water, respectively, and then dried with high-purity nitrogen to obtain a clean and dry gallium buffer layer.

[0085] S5, Gallium oxide thin film preparation

[0086] The target material was selected as a high-purity gallium oxide ceramic target with a purity of 99.99%. The gallium buffer layer and substrate obtained in step S4 were placed on the sample stage. After the sputtering chamber was evacuated, the substrate temperature was raised to 400℃. After the temperature stabilized, argon gas with a flow rate of 25 sccm was introduced, and the vacuum degree of the chamber was adjusted to 5 Pa. The sputtering pressure and sputtering power were set to 0.4 Pa and 60 W, respectively, and the sample tray rotation speed was ≤5 rad / min. After pre-sputtering for 30 min, the baffle was opened to start the formal sputtering. After the sputtering was completed, a gallium oxide thin film with a thickness of 100 nm was prepared on the gallium buffer layer.

[0087] Example 5

[0088] A method for preparing a gallium oxide thin film based on a gallium buffer layer includes the following steps:

[0089] S1, Substrate processing:

[0090] A quartz substrate with dimensions of 19.5 mm × 19.5 mm and a thickness of 1 mm was selected. The substrate was ultrasonically treated in acetone, methanol, and deionized water for 10 min each, and then dried with high-purity nitrogen to obtain a clean and dry substrate.

[0091] S2, Gallium metal layer fabrication:

[0092] The clean and dry substrate obtained in step S1 is placed into the electron beam evaporation chamber. The metal to be deposited is gallium, and the process parameters are set to gallium and the film thickness is set. The electron beam equipment is powered on, and after preheating is complete, the power is increased at a rate of 5% per minute, and the temperature is maintained for 30 seconds. The beam current is then observed, and the beam spot is adjusted to be located inside the crucible without contacting the crucible wall. After the power reaches 30%, the increase rate is maintained at 1% per minute until the film deposition rate reaches [a certain value]. The formal evaporation process was carried out, and after the evaporation was completed, a gallium metal layer with a thickness of 20 nm was prepared on the substrate.

[0093] S3. Post-annealing treatment:

[0094] The substrate and gallium metal layer obtained in step S2 are placed in a rapid annealing furnace for annealing post-treatment; the annealing temperature is 700℃ and the annealing time is 60min. After annealing, the gallium film is cooled to room temperature and then removed to obtain a gallium buffer layer with a uniform and dense structure.

[0095] S4, Buffer layer cleaning

[0096] To remove impurities generated in the gallium buffer layer during the annealing process, the gallium buffer layer obtained in step S3 was ultrasonically cleaned for 10 minutes with deionized water, acetone, methanol, and deionized water, respectively, and then dried with high-purity nitrogen to obtain a clean and dry gallium buffer layer.

[0097] S5, Gallium oxide thin film preparation

[0098] The target material was selected as a high-purity gallium oxide ceramic target with a purity of 99.99%. The gallium buffer layer and substrate obtained in step S4 were placed on the sample stage. After the sputtering chamber was evacuated, the substrate temperature was raised to 400℃. After the temperature stabilized, argon gas with a flow rate of 25 sccm was introduced, and the vacuum degree of the chamber was adjusted to 5 Pa. The sputtering pressure and sputtering power were set to 0.4 Pa and 60 W, respectively, and the sample tray rotation speed was ≤5 rad / min. After pre-sputtering for 30 min, the baffle was opened to start the formal sputtering. After the sputtering was completed, a gallium oxide thin film with a thickness of 100 nm was prepared on the gallium buffer layer.

[0099] Example 6

[0100] It is almost identical to Example 1, except that the thickness of the gallium metal layer in step S2 is 10 nm.

[0101] Example 7

[0102] Most of the components are the same as in Example 1, except that the thickness of the gallium oxide film is 120 nm in step S5.

[0103] Example 8

[0104] Most of the components are the same as in Example 1, except that the thickness of the gallium oxide film is 150 nm in step S5.

[0105] Comparative Example 1

[0106] A quartz substrate measuring 19.5 mm × 19.5 mm with a thickness of 1 mm was selected. The substrate was ultrasonically treated in acetone, methanol, and deionized water for 10 min each, and then dried with high-purity nitrogen to obtain a clean and dry substrate. A high-purity gallium oxide ceramic target with a purity of 99.99% was selected. The substrate was placed on the sample stage, and after evacuating the sputtering chamber, the substrate temperature was raised to 400℃. After the temperature stabilized, argon gas was introduced at a flow rate of 25 sccm, and the chamber vacuum was adjusted to 5 Pa. The sputtering pressure and sputtering power were set to 0.4 Pa and 60 W, respectively, and the sample tray rotation speed was ≤5 rad / min. After 30 min of pre-sputtering, the baffle was opened to begin the formal sputtering. After sputtering was completed, a gallium oxide thin film with a thickness of 100 nm was prepared on the gallium buffer layer.

[0107] Performance testing

[0108] I. Study on the Influence of Gallium Buffer Layer Annealing Temperature on Gallium Oxide Thin Film and Solar-Blind Ultraviolet Detection Performance

[0109] The solar-blind ultraviolet detection performance of the gallium oxide thin films obtained in Examples 1, 4, 5 and Comparative Example 1 was analyzed. In Example 1 (annealing temperature of 500℃), Example 4 (annealing temperature of 600℃), Example 5 (annealing temperature of 700℃) and Comparative Example 1 (without gallium buffer layer) were coated with titanium / chromium (Ti / Cr) composite electrodes. The thickness of titanium (Ti) and chromium (Cr) was 50 nm. Solar-blind ultraviolet detectors were prepared and were designated as samples TG500J, TG600J, TG700J and TG0J, respectively.

[0110] The electrical performance of solar-blind ultraviolet detectors fabricated from gallium oxide thin films prepared by magnetron sputtering on buffer layers at different annealing temperatures was tested in a dark environment under irradiation with 254 nm solar-blind ultraviolet light and 365 nm ultraviolet light. The test results are as follows: Figure 4As shown, comparing the light and dark IV curves of the detector under darkness, and under 254nm solar-blind ultraviolet light and 365nm ultraviolet light illumination, it can be seen that the IV curves of the solar-blind ultraviolet detector TG0J without a gallium buffer layer are almost identical under 365nm light illumination and in darkness, indicating that this detector has almost no response to 365nm light. Under 254nm light illumination, the current increases slightly, but the response is also very weak. The light-dark current ratio was calculated with a bias voltage of 10V. The light-dark current ratio I of the detector TG0J without a buffer layer is... 254 / I dark It is 1.75.

[0111] The light and dark current response curves of the solar-blind ultraviolet detector fabricated from gallium oxide thin films with the addition of a gallium buffer layer showed significant changes, with a substantial increase in the light-to-dark current ratio. Calculations using a bias voltage of 10V revealed that at an annealing temperature of 500℃, the detector's light-to-dark current ratio I... 254 / I dark The detector's light-to-dark ratio is 2947.51 at an annealing temperature of 600℃. 254 / I dark The detector's light-to-dark ratio I is 4797.12 at an annealing temperature of 700℃. 254 / I dark The value is 1440.93. The addition of the buffer layer greatly improves the light-dark current ratio of the detection device. After adding the buffer layer, the light-dark current ratio of the ultraviolet detector is greatly improved compared with the original device, by three orders of magnitude.

[0112] like Figure 5 As shown, comparing the dark currents of ultraviolet detectors fabricated from gallium oxide films annealed at different temperatures reveals that detectors annealed at 500℃ and 600℃ exhibit lower dark currents. This is because annealing at lower temperatures reduces the lattice mismatch between the gallium oxide film and the substrate, decreasing leakage current at the heterojunction and resulting in lower dark currents. Conversely, detectors annealed at 700℃ exhibit higher dark currents. This is likely because at excessively high annealing temperatures, the difference in thermal expansion coefficients between the buffer layer and the substrate leads to greater thermal stress and physical defects after annealing, thus increasing the dark current.

[0113] II. Study on the Influence of Gallium Buffer Layer Thickness on Gallium Oxide Thin Film and Solar-Blind Ultraviolet Detection Performance

[0114] The solar-blind ultraviolet detection performance of the gallium oxide thin films obtained in Examples 1, 2, 3 and Comparative Example 1 was analyzed. The solar-blind ultraviolet detectors prepared in Examples 1 (gallium buffer layer thickness of 20 nm), 2 (gallium buffer layer thickness of 50 nm), 3 (gallium buffer layer thickness of 80 nm), and Comparative Example 1 (without gallium buffer layer) were respectively designated as samples SG20J, SG50J, SG80J and SG0J.

[0115] The electrical performance of solar-blind ultraviolet detectors fabricated from gallium oxide thin films prepared by magnetron sputtering on buffer layers of different thicknesses was tested in a dark environment under irradiation with 254 nm solar-blind ultraviolet light and 365 nm ultraviolet light. The test results are as follows: Figure 6 As shown, it can be observed that the solar-blind ultraviolet detector SG0J without a buffer layer has almost no response under 365nm wavelength light illumination, and the response is also very weak under 254nm wavelength light illumination. Calculations of the light-dark ratio at a bias voltage of 10V reveal that the light-dark ratio I of the detector SG0J without a buffer layer is... 254 / I dark It is 1.75.

[0116] After introducing a buffer layer, the response of the solar-blind ultraviolet detector under illumination showed a significant improvement. Different thicknesses of the buffer layer also resulted in significantly different gains for the ultraviolet detector. Calculations of the light-dark ratio at a bias voltage of 10V revealed that when the buffer layer thickness was 20nm, the detector's light-dark ratio I... 254 / I dark When the value is 8.35 and the buffer layer thickness is 50 nm, the detector's light-to-dark ratio I 254 / I dark When the detector's light-to-dark ratio is 4797.12 and the buffer layer thickness is 80 nm, the detector's light-to-dark ratio I is... 254 / I dark The value was 37.76. Therefore, it was found that the addition of the buffer layer greatly improved the photocurrent-to-dark-current ratio of the detection device.

[0117] Regarding the UV-Vis suppression ratio, the UV-Vis suppression ratio I of each detector was measured at a bias voltage of 10V. 254 / I 365 Calculations revealed that the suppression ratio I of ultraviolet detectors with buffer layer thicknesses of 0nm, 20nm, 50nm, and 80nm was [missing information]. 254 / I 365 The values ​​were 1.58, 9.56, 1043.30, and 19.99, respectively. Among them, a buffer layer thickness of 50 nm significantly improved the suppression ratio.

[0118] In summary, the addition of a gallium buffer layer significantly improves the quality of the prepared gallium oxide thin film, while the thickness of the gallium buffer layer and the annealing temperature affect the extent of the quality improvement. This invention utilizes a gallium buffer layer to prepare a high-performance gallium oxide thin film. The gallium oxide thin film of this invention is prepared by radio frequency magnetron sputtering, which is simpler to operate, lower in cost, and can be prepared on a large area with high feasibility for batch growth compared to other growth processes.

[0119] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for producing a gallium-oxide thin film based on a gallium buffer layer, characterized by, It comprises the following steps: S1, substrate processing: the substrate is sequentially cleaned with acetone, methanol and deionized water, and dried with high-purity nitrogen to obtain a clean and dry substrate; S2, gallium metal layer preparation: the clean and dry substrate obtained in step S1 is coated with gallium by electron beam evaporation to prepare a gallium metal layer on the substrate; S3, annealing post-processing: the substrate and gallium metal layer obtained in step S2 are subjected to annealing post-processing, and after annealing, the gallium buffer layer is prepared on the substrate after cooling; S4, gallium buffer layer cleaning: the gallium buffer layer obtained in step S3 is sequentially cleaned with acetone, methanol and deionized water, and dried with high-purity nitrogen to obtain a clean and dry gallium buffer layer; S5, gallium oxide film preparation: a gallium oxide ceramic target is selected as the target material, and a gallium oxide film is prepared on the clean and dry gallium buffer layer obtained in step S4 by using a magnetron sputtering method; In step S2, the specific operation process of electron beam evaporation of gallium is as follows: the clean and dry substrate obtained in step S1 is sent into the electron beam evaporation cavity, the evaporation metal is set to gallium, the process parameters are loaded as gallium process and the corresponding film thickness is set; turn on the power of the electron beam device, wait for preheating, increase the power at a rate of 2% to 10% per minute, and keep warm for 10 to 60 seconds, wait for the beam current to appear and adjust the spot to be located in the crucible without touching the crucible wall; keep the growth rate at 1% to 5% per minute after the power reaches 20% to 60%, until the film deposition rate is greater than or equal to 0.6 angstrom per second, then start evaporation, and a gallium metal layer is prepared on the substrate after evaporation is completed; In step S3, the annealing temperature is 400 to 800℃, the annealing time is 30 to 120 minutes, and the cooling temperature is room temperature.

2. The method of claim 1, wherein the gallium buffer layer is formed by a method comprising: depositing a gallium layer on a substrate; and annealing the gallium layer at a temperature of 300-600 °C in an atmosphere containing oxygen. In step S1, the substrate material includes inorganic material or semiconductor material.

3. The method of claim 1, wherein the gallium buffer layer is formed by a method comprising: depositing a gallium layer on a substrate; and annealing the gallium layer at a temperature of 300-600 °C in an atmosphere containing oxygen. In step S2, the thickness of the gallium metal layer prepared is 10 to 80 nm.

4. The method of claim 1, wherein the gallium buffer layer is formed by a method comprising: depositing a gallium layer on a substrate; and annealing the gallium layer at a temperature of 300-600 °C in an atmosphere containing oxygen. In step S3, the temperature is raised at a rate of greater than or equal to 6℃ / min, and the temperature is kept for 40 to 80 minutes before cooling.

5. The method of claim 1, wherein the gallium buffer layer is formed by a method comprising: depositing a gallium layer on a substrate; and annealing the gallium layer at a temperature of 300-600 °C in an atmosphere containing oxygen. In step S5, the specific operation process of the magnetron sputtering method is as follows: the gallium buffer layer and the substrate obtained in step S4 are placed on the sample stage, the substrate temperature is raised to 300 to 600℃ after the sputtering cavity is evacuated, the argon gas flow is adjusted to 15 to 30 sccm after the temperature is stable, and the cavity vacuum degree is adjusted to 5 to 7 Pa; the sputtering pressure and the sputtering power are set to 0.4 to 0.5 Pa and 50 to 80 W respectively, the sample tray rotation speed is less than or equal to 5 rad / min, the shutter is opened after pre-sputtering for 10 to 30 minutes to start formal sputtering, and a gallium oxide film is prepared on the gallium buffer layer after sputtering is completed.

6. The method of claim 1, wherein the gallium buffer layer is formed by a method comprising: depositing a gallium layer on a substrate; and annealing the gallium layer at a temperature of 300-600 °C in an atmosphere containing oxygen. In step S5, the thickness of the gallium oxide film prepared is 10 to 80 nm.

7. A gallium oxide film based on a gallium buffer layer, which is prepared by the preparation method of any one of claims 1 to 6.

8. The application of a gallium oxide film based on a gallium buffer layer in ultraviolet detection, light emitting devices or solar cells.

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