An epsilon-ga2o3 thin film, a metastable phase gallium oxide ultraviolet detector and a preparation method thereof

Abstract

This invention belongs to the field of wide bandgap semiconductor fabrication technology, and discloses a... e The invention relates to a Ga2O3 thin film, a metastable gallium oxide ultraviolet detector, and their fabrication method, comprising the following steps: heating a cleaned pretreated substrate to 550-610°C, introducing a mixture of carrier gas and dilution gas into the substrate for a set time, and epitaxially performing low-doped... e -Ga2O3 thin film; after growth, the temperature inside the reaction chamber is heated to 620-700℃, and highly doped epitaxial film is grown. e -Ga₂O₃ thin film. The combination of a bilayer structure and doping helps alleviate lattice mismatch and promotes... e - The formation of Ga2O3. During Ge doping, Ge... 4+ Successfully replaced Ga 3+ This leads to a decrease in the lattice constant, thereby relieving the compressive stress on the thin film, making... e The crystal quality of the Ga2O3 epitaxial film has been improved.

Description

Technical Field

[0001] This invention relates to the field of wide bandgap semiconductor fabrication technology, specifically to a... epsilon -Ga2O3 thin film, metastable gallium oxide ultraviolet detector and its preparation method. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Deep ultraviolet (DUV) detectors operate in the 200-280 nm wavelength range and possess advantages such as resistance to environmental interference, high signal-to-noise ratio, and high precision. They are widely used in fields such as flame detection, missile tracking, solar blind imaging, and ultraviolet communication. Ga2O3, a semiconductor material, is an ideal material for DUV detectors due to its ultra-wide bandgap, high breakdown electric field strength, and high Barley figure of merit. epsilon Ga2O3, with its higher symmetry, strong polarization effect, and deeper intrinsic ultraviolet response, offers more possibilities for novel detector structures.

[0004] However, currently due to epsilon -Ga₂O₃ heteroepitaxial growth exhibits significant lattice mismatch, leading to a rotating domain structure in the film and significantly reducing its crystallinity. Furthermore, traditional UIDs... epsilon Ga2O3-based photodetectors exhibit low photocurrent and slow response speed, which severely limits their application. epsilon The ability of Ga2O3-based photodetectors to monitor weak signals hinders the realization of multifunctional applications and makes it difficult to meet the stringent performance requirements of high-performance electronic devices.

[0005] Although there are methods for preparing n-type doped materials... epsilon While there has been research on Ga2O3 thin films, the doping technology is not mature, and the performance of the prepared semiconductor devices is difficult to meet the requirements. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a... epsilon -Ga2O3 thin film, metastable gallium oxide ultraviolet detector and its preparation method.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] In a first aspect, the present invention provides epsilon The method for preparing Ga2O3 thin films includes the following steps: heating a cleaned and pretreated substrate to 550-610℃, introducing a mixture of carrier gas and dilution gas into the substrate for a set time, then atomizing and adding a low-doped gallium oxide precursor solution with a Ge doping concentration of 1-5%, and epitaxially...epsilon -Ga2O3 thin film;

[0009] After the growth is completed, the temperature in the reaction cavity is heated to 620-700 DEG C, the atmosphere is kept unchanged, the high-doped gallium oxide precursor solution with Ge doping concentration of 5-8% is atomized and added, and the high-doped gallium oxide is epitaxially grown on the low-doped gallium oxide film. epsilon -Ga2O3 thin film.

[0010] In the second aspect, the present application provides a method for preparing a metastable phase gallium oxide ultraviolet detector. epsilon -Ga2O3 thin film prepared by the preparation method.

[0011] In the third aspect, the present application provides a metastable phase gallium oxide ultraviolet detector, which comprises a C-surface sapphire substrate, a low-doped gallium oxide film attached to the surface of the C-surface sapphire substrate, epsilon -Ga2O3 thin film and a high-doped gallium oxide film attached to the surface of the low-doped gallium oxide film. epsilon -Ga2O3 thin film and a high-doped gallium oxide film attached to the surface of the low-doped gallium oxide film. epsilon -Ga2O3 thin film and a high-doped gallium oxide film attached to the surface of the low-doped gallium oxide film. epsilon -Ga2O3 thin film and a high-doped gallium oxide film attached to the surface of the low-doped gallium oxide film.

[0012] The beneficial effects achieved by one or more embodiments of the present application are as follows:

[0013] epsilon -Ga2O3 is a semiconductor wafer, and at present epsilon The existence of the metastable phase gallium oxide hetero-epitaxial rotation domain makes the film quality poor and the epitaxial doping immature, resulting in a poor performance of the solar blind detector prepared thereby, a long response time and a low light-dark current, which seriously limits the possibility of detecting weak signals and realizing multifunctional applications.

[0014] The present application first proposes a method combining a double-layer structure with a doping process to relieve lattice mismatch and promote the formation of epsilon -Ga2O3. In the Ge doping process, Ge 4+ successfully replaces Ga 3+ , resulting in a smaller lattice constant and relieving the film compressive stress, so that epsilon -Ga2O3 epitaxial film has improved crystal quality, and the film defects are reduced, which is beneficial to the improvement of device performance.

[0015] In addition, by alternating epitaxy of low-temperature low-doping and high-temperature high-doping, efficient Ge doping is realized, the film carrier concentration is improved, and the device photocurrent is improved. A low-dark-current, high-detection-rate solar blind photodetector is prepared.

[0016] The preparation method of the present application has the advantages of simple preparation process, flexible operation and low cost, and has a good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application and are incorporated herein in

[0018] Figure 1 SEM image of the double layer Ge doped epsilon XRD rocking curve of the (002) plane of the Ga2O3 film;

[0019] epsilon SEM image of the double layer Ge doped Figure 2 SEM image of the double layer Ge doped

[0020] epsilon XPS Ge3d spectrum of the double layer Ge doped Figure 3 XPS Ge3d spectrum of the double layer Ge doped

[0021] epsilon Structure diagram of the ultraviolet detector provided by the present application;

[0022] Figure 4 I-V test diagram of the device prepared in Example 1 of the present application;

[0023] Figure 5 I-V test diagram of the device prepared in Example 2 of the present application;

[0024] Figure 6 I-V test diagram of the device prepared in Example 3 of the present application;

[0025] Figure 7 I-V test diagram of the device prepared in Comparative Example 1 of the present application;

[0026] Figure 8 I-V test diagram of the device prepared in Comparative Example 2 of the present application;

[0027] Figure 9 I-V test diagram of the device prepared in Comparative Example 3 of the present application. DETAILED DESCRIPTION

[0028] It should be noted that the following detailed description is merely illustrative and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0029] In a first aspect, the present application provides a method for preparing a Ga2O3 film, comprising the following steps: Figure 10 In a first aspect, the present application provides a method for preparing a Ga2O3 film, comprising the following steps:

[0030] The clean pretreated substrate is heated to 550-610 DEG C, and a mixed gas of carrier gas and dilution gas is introduced into the substrate for a set time, then a low-doped gallium oxide precursor solution with a Ge doping concentration of 1-5% is atomized and added, and a low-doped epsilon -Ga2O3 film is epitaxially grown.

[0031] After the growth is completed, the temperature in the reaction cavity is heated to 620-700 DEG C, the atmosphere is kept unchanged, a high-doped gallium oxide precursor solution with a Ge doping concentration of 5-8% is atomized and added, and a high-doped epsilon -Ga2O3 film is epitaxially grown.

[0032] The doping concentration of Ge is the doping ratio of germanium element to gallium element.

[0033] The substrate can be a C-sapphire substrate, an aluminum nitride substrate, or a gallium nitride substrate, etc.

[0034] The n-type doping of gallium oxide is usually doped with Si, Sn, etc., but the doping effect is not good. By comparing the density Nd1 and Nd2 of each dopant and two donor energy levels, it is found that the donor energy level density caused by Ge doping is larger, which further shows that for the similar doping concentration of Ge and Si, the doping effect of Ge is better.

[0035] Ge-doped epsilon -Ga2O3 films are epitaxially grown on C-sapphire by using a Mist-CVD method. Compared with traditional doping, not only the preparation cost is significantly reduced, but also high-efficiency n-type doped films are prepared by using suitable dopants, which provides a scheme for preparing high-performance solar blind detectors.

[0036] Under normal pressure, argon is used as the carrier gas, oxygen is used as the dilution gas, the solution is ultrasonically atomized and then delivered to the surface of the pretreated substrate, a low-temperature low-doped layer is first formed at 550-610 DEG C, then the temperature is raised to 620-700 DEG C to epitaxially form a high-temperature high-doped layer, and a double-layer Ge epsilon -Ga2O3 film is obtained. The doping not only relieves the lattice stress and improves the film quality, but also improves the device performance through effective doping.

[0037] In some embodiments, the clean pretreatment method is that the substrate is sequentially ultrasonically cleaned with isopropyl alcohol, ethanol, and deionized water, and then dried with nitrogen.

[0038] In some embodiments, the concentration of gallium acetylacetonate in the low-doped gallium oxide precursor solution and / or the high-doped gallium oxide precursor solution is 0.01-0.1 mol / L.

[0039] Preferably, the concentration of gallium acetylacetonate is 0.03-0.07 mol / L, preferably 0.05 mol / L.

[0040] In some embodiments, the Ge dopant is germanium iodide.

[0041] In some embodiments, the epitaxial low-doped Ga2O3 film has a thickness of 3-7 μm. epsilon The epitaxial high-doped Ga2O3 film has a thickness of 1.5-2.5 μm and a temperature of 630-660 °C. epsilon The epitaxial high-doped Ga2O3 film has a thickness of 1.5-2.5 μm and a temperature of 630-660 °C.

[0042] Preferably, the epitaxial low-doped Ga2O3 film has a thickness of 3-7 μm. epsilon The epitaxial high-doped Ga2O3 film has a thickness of 1.5-2.5 μm and a temperature of 630-660 °C. epsilon The epitaxial high-doped Ga2O3 film has a thickness of 1.5-2.5 μm and a temperature of 630-660 °C.

[0043] In some embodiments, the carrier gas is argon and the diluent gas is oxygen.

[0044] In a second aspect, the present application provides a method for preparing a metastable phase gallium oxide ultraviolet detector. epsilon The metastable phase gallium oxide ultraviolet detector is prepared by the method.

[0045] In some embodiments, the epitaxial low-doped Ga2O3 film has a thickness of 3-7 μm. epsilon The epitaxial low-doped Ga2O3 film has a thickness of 3-7 μm and a rocking curve half-height width of 0.53°.

[0046] In a third aspect, the present application provides a metastable phase gallium oxide ultraviolet detector, comprising a substrate, a low-doped Ga2O3 film attached to the surface of the substrate, epsilon a high-doped Ga2O3 film attached to the surface of the low-doped Ga2O3 film, epsilon a high-doped Ga2O3 film attached to the surface of the low-doped Ga2O3 film, epsilon a high-doped Ga2O3 film attached to the surface of the low-doped Ga2O3 film, epsilon an electrode attached to the surface of the high-doped Ga2O3 film.

[0047] The substrate can be a C-plane sapphire substrate, an aluminum nitride substrate, or a gallium nitride substrate, etc.

[0048] In some embodiments, the electrode is a titanium-gold electrode, the thickness of the titanium layer is 15-25 nm, and the thickness of the gold layer is 20-40 nm.

[0049] Preferably, the titanium-gold electrode is an interdigital electrode.

[0050] The device of the interdigital electrode has 13 pairs of interdigital electrodes, the length of which is 500 μm, the finger spacing is 10 μm, and the effective irradiation area is 1.25 x 10 -3 cm 2 .

[0051] The method achieves a high efficiency of 60%-80% Ge dopingepsilon -Ga2O3 thin film, and the film quality is high, with a rocking curve as low as 0.35°.

[0052] The present invention will be further described below with reference to the embodiments.

[0053] Example 1

[0054] s1: Substrate pretreatment

[0055] The C-side sapphire substrate was ultrasonically cleaned sequentially with isopropanol, ethanol, and deionized water for 2 minutes each time to remove any impurities. After each chemical cleaning, the substrate was dried using high-purity nitrogen gas (purity ≥ 99.999%) to ensure the substrate surface was dry and free of watermarks.

[0056] s2: Precursor solution preparation

[0057] First, prepare a 1% Ge-doped precursor solution. This requires accurately weighing 1.85 g of 99.99% pure gallium acetylacetonate and 0.029 g of 99.99% pure germanium iodide (the doping concentration refers to the ratio of germanium to gallium; the gallium solution ratio is 0.05 mol / L, so to prepare 1% germanium iodide relative to gallium acetylacetonate, the molar concentration of germanium iodide is 0.0005 mol / L, and its molecular weight is 580.26. To prepare 100 mL of solution, the calculated value is m = 0.0005 × 0.1 × 580.26, which is 0.029 g; the same applies below). Dissolve these powders in 100 mL of deionized water and add 1.52 mL of 36% concentrated hydrochloric acid to promote the dissolution of gallium acetylacetonate. Next, prepare a 5% Ge-doped precursor solution. Accurately weigh 1.85 g of 99.99% pure gallium acetylacetonate and 0.145 g of 99.99% pure germanium iodide, respectively. Dissolve these powders in 100 mL of deionized water, and add 1.52 mL of 36 wt% concentrated hydrochloric acid to promote the dissolution of gallium acetylacetonate. Stir the beaker with a magnetic stirrer at room temperature for 6 hours to ensure all powders are completely dissolved. After stirring, allow the solution to stand for at least 2 hours to allow insoluble impurities to settle for later use.

[0058] s3: CVD epitaxial growth

[0059] Secure the sapphire crystal in the upper connecting rod and adjust its height to ensure the distance between the substrate and the reaction source is precisely controlled at 15mm. Set the reaction chamber heating temperature to 600℃. Once the target temperature is reached, set the argon flow rate to 2L / min and the oxygen flow rate to 0.3L / min, precisely controlled by a mass flow controller. Before starting atomization, maintain the carrier gas path for at least 1 hour to ensure the gas fills the entire reaction chamber.

[0060] Subsequently, the precursor solution with 1% Ge doping concentration was added into the ultrasonic atomization tank and the atomization was started, the gas transported the atomized liquid into the reaction chamber for deposition growth for 2h.

[0061] Then the temperature was raised to 640℃ and kept for 1h, after ensuring the stability in the reaction chamber, the precursor solution with 5% Ge doping concentration was introduced, the atomization was started for 2h, and the double-layer Ge-doped epsilon -Ga2O3 film was obtained.

[0062] s4: device preparation process

[0063] After spin-coating photoresist on the epitaxial wafer, a mask with a specific pattern was placed for photoetching of the MSM structure electrode pattern, wherein the exposure time was set to 7s; after the end, it was placed in the developing solution for 30s for development, the sample was rinsed and dried with a nitrogen gun; then, the titanium / gold electrode was evaporated on the thin film with the photoetching pattern by electron beam evaporation technology, the thickness of the titanium layer was 20nm, and the thickness of the gold layer was 30nm, wherein the evaporation rate was 2Å / s; finally, the colloidal mask was removed by ultrasonic. The prepared device was annealed at 500℃ in a nitrogen atmosphere for 3min to promote the ohmic contact between the thin film and the electrode; I-V test was performed by using a direct current probe table.

[0064] Example 2

[0065] The difference from Example 1 is that steps s2 and s3, and the rest are the same as Example 1.

[0066] s2: precursor solution configuration

[0067] First, the precursor solution with 2% Ge doping concentration was configured, 1.85 grams of gallium acetylacetonate with a purity of 99.99% and 0.058 grams of germanium iodide with a purity of 99.99% were accurately weighed, and the powders were dissolved in 100 milliliters of deionized water, and 1.52 milliliters of 36wt% concentrated hydrochloric acid was added to promote the dissolution of gallium acetylacetonate. Secondly, the precursor solution with 5% Ge doping concentration was configured, 1.85 grams of gallium acetylacetonate with a purity of 99.99% and 0.145 grams of germanium iodide with a purity of 99.99% were accurately weighed, and the powders were dissolved in 100 milliliters of deionized water, and 1.52 milliliters of 36% concentrated hydrochloric acid was added to promote the dissolution of gallium acetylacetonate. Both beakers were stirred at room temperature for 6 hours using a magnetic stirrer to ensure that all the powders were completely dissolved. After the stirring was completed, the solution was left to stand for at least 2 hours so that the insoluble impurities could settle for later use.

[0068] s3: CVD epitaxial growth

[0069] The sapphire is fixed in the upper connecting rod, and the height of the upper connecting rod is adjusted to ensure that the distance between the substrate and the reaction source is accurately controlled at 15 mm. The heating temperature of the reaction chamber is set to 600°C, and after reaching the target temperature, the argon flow is set to 2 L / min and the oxygen flow is set to 0.3 L / min, which is accurately controlled by the mass flow controller. Before starting the atomization, keep the carrier gas path ventilated for at least 1 hour to ensure that the gas fills the entire reaction chamber.

[0070] Subsequently, the prepared precursor solution with a Ge doping concentration of 2% is added to the ultrasonic atomization tank and the atomization is started, and the gas transports the atomized liquid into the reaction chamber to deposit and grow for 2 hours.

[0071] Then the temperature is raised to 640°C and kept for 1 hour, and after ensuring the stability of the reaction chamber, the precursor solution with a Ge doping concentration of 5% is introduced, and the atomization is started for 2 hours to obtain a double-layer Ge-doped epsilon -Ga2O3 film.

[0072] Example 3

[0073] The difference from Example 1 is that steps s2 and s3, and the rest are the same as Example 1.

[0074] s2: Preparation of precursor solution

[0075] First, prepare a precursor solution with a Ge doping concentration of 5%, accurately weigh 1.85 grams of gallium acetylacetonate with a purity of 99.99% and 0.145 grams of germanium iodide with a purity of 99.99%, and dissolve these powders in 100 milliliters of deionized water, and add 1.52 milliliters of 36wt% concentrated hydrochloric acid to promote the dissolution of gallium acetylacetonate. Second, prepare a precursor solution with a Ge doping concentration of 5%, accurately weigh 1.85 grams of gallium acetylacetonate with a purity of 99.99% and 0.145 grams of germanium iodide with a purity of 99.99%, and dissolve these powders in 100 milliliters of deionized water, and add 1.52 milliliters of 36wt% concentrated hydrochloric acid to promote the dissolution of gallium acetylacetonate. The beakers are stirred at room temperature using a magnetic stirrer for 6 hours to ensure that all the powders are completely dissolved. After stirring is complete, the solution is left to stand for at least 2 hours to allow insoluble impurities to settle for later use.

[0076] s3: CVD epitaxial growth

[0077] The sapphire is fixed in the upper connecting rod, and the height of the upper connecting rod is adjusted to ensure that the distance between the substrate and the reaction source is accurately controlled at 15 mm. The heating temperature of the reaction chamber is set to 600°C, and after reaching the target temperature, the argon flow is set to 2 L / min and the oxygen flow is set to 0.3 L / min, which is accurately controlled by the mass flow controller. Before starting the atomization, keep the carrier gas path ventilated for at least 1 hour to ensure that the gas fills the entire reaction chamber.

[0078] Subsequently, the prepared precursor solution with 5% Ge doping concentration was added into the ultrasonic atomization tank and atomization was started, and the gas transported the atomized liquid into the reaction chamber for deposition growth for 2 h.

[0079] Then the temperature was raised to 640°C and kept for 1 h, and after ensuring the stability of the reaction chamber, the precursor solution with 5% Ge doping concentration was introduced, and atomization was started for 2 h to obtain a double-layer Ge-doped epsilon -Ga2O3 film.

[0080] Comparative Example 1

[0081] s1: Substrate pretreatment

[0082] The C-plane sapphire substrate was sequentially subjected to ultrasonic cleaning with isopropanol, ethanol, and deionized water for 2 minutes each. After each chemical cleaning, the substrate was dried with high-purity nitrogen (purity above 99.999%) to ensure that the substrate surface was dry and free of water marks.

[0083] s2: Preparation of precursor solution

[0084] First, the precursor solution was prepared by accurately weighing 1.85 grams of gallium acetylacetonate with a purity of 99.99% and dissolving it in 100 milliliters of deionized water, and adding 1.52 milliliters of 36wt% concentrated hydrochloric acid to promote the dissolution of gallium acetylacetonate. The beaker was stirred at room temperature for 6 hours using a magnetic stirrer to ensure complete dissolution of all powders. After stirring, the solution was left to stand for at least 2 hours to allow insoluble impurities to settle for later use.

[0085] s3: CVD epitaxial growth

[0086] The sapphire was fixed in the upper connecting rod, and the height of the upper connecting rod was adjusted to ensure that the distance between the substrate and the reaction source was accurately controlled at 15 mm. The heating temperature of the reaction chamber was set to 600°C, and after reaching the target temperature, the argon flow was set to 2 L / min and the oxygen flow was set to 0.2 L / min, which were accurately controlled by mass flow controllers. Before starting atomization, the gas path was ventilated for at least 1 hour to ensure that the gas filled the entire reaction chamber.

[0087] Subsequently, the prepared precursor solution was added into the ultrasonic atomization tank and atomization was started, and the gas transported the atomized liquid into the reaction chamber for deposition growth for 2 h to obtain an unintentionally doped epsilon -Ga2O3 film.

[0088] s4: Device preparation process

[0089] After spin-coating photoresist on the epitaxial wafer, a mask with a specific pattern is placed for the photolithography of the MSM structure electrode pattern, where the exposure time is set to 7 s; after the end, it is placed in the developing solution for 30 s to develop, and the sample is rinsed and dried with a nitrogen gun; then, the titanium / gold electrode is evaporated on the thin film with a lithographic pattern using electron beam evaporation technology, where the evaporation rate is 2 A / s; finally, the colloidal mask is removed by ultrasonic.

[0090] The prepared device is annealed at 500°C in a nitrogen atmosphere for 3 min to promote the ohmic contact between the thin film and the electrode; the I-V test is performed using a direct current probe table.

[0091] Comparative Example 2

[0092] s1: Substrate pretreatment

[0093] The C-surface sapphire substrate is sequentially ultrasonically cleaned with isopropanol, ethanol, and deionized water for 2 minutes each to remove any impurities. After each chemical cleaning, the substrate is blown dry with high-purity nitrogen (purity above 99.999%) to ensure that the substrate surface is dry and free of water marks.

[0094] s2: Preparation of precursor solution

[0095] First, a 5% Ge-doped precursor solution is prepared by accurately weighing 3.7 grams of 99.99% pure gallium acetylacetonate and 0.29 grams of 99.99% pure germanium iodide, and dissolving these powders in 200 milliliters of deionized water. Then, 3.04 milliliters of 36wt% concentrated hydrochloric acid is added to facilitate the dissolution of the gallium acetylacetonate. The beaker is stirred at room temperature using a magnetic stirrer for 6 hours to ensure complete dissolution of all powders. After stirring is complete, the solution is allowed to stand for at least 2 hours to allow insoluble impurities to settle for later use.

[0096] s3: CVD epitaxial growth

[0097] The sapphire is fixed in the upper connecting rod, and the height of the upper connecting rod is adjusted to ensure that the distance between the substrate and the reaction source is accurately controlled at 15 mm. The reaction chamber heating temperature is set to 640°C, and after reaching the target temperature, the argon flow is set to 2 L / min and the oxygen flow is set to 0.3 L / min, which are accurately controlled by mass flow controllers. Before starting the atomization, the gas path is kept open for at least 1 hour to ensure that the gas fills the entire reaction chamber.

[0098] Subsequently, the 5% Ge-doped precursor solution is added to the ultrasonic atomization tank and the atomization is started, and the gas transports the atomized liquid to the reaction chamber for deposition and growth for 4 hours to obtain a single-layer Ge-doped Ga2O3 thin film. epsilon

[0099] s4: Device preparation process ​

[0100] After spin-coating photoresist on the epitaxial wafer, a mask with a specific pattern was placed for the photolithography of the MSM structure electrode pattern, with an exposure time of 7 s; after the end, it was placed in the developing solution for 30 s of shaking for development, and the sample was rinsed and dried with a nitrogen gun; then, the titanium / gold electrode was evaporated on the thin film with a lithographic pattern using electron beam evaporation technology, with an evaporation rate of 2 A / s; finally, the colloidal mask was removed by ultrasonic.

[0101] Comparative Example 3

[0102] The difference from Example 1 is that steps s2 and s3, and the rest are the same as Example 1.

[0103] s2: Preparation of precursor solution

[0104] First, a precursor solution with a Ge doping concentration of 1% was prepared by accurately weighing 3.7 grams of gallium acetylacetonate with a purity of 99.99% and 0.058 grams of germanium iodide with a purity of 99.99%, and dissolving these powders in 200 milliliters of deionized water, and adding 3.04 milliliters of 36wt% concentrated hydrochloric acid to promote the dissolution of gallium acetylacetonate.

[0105] The beaker was stirred at room temperature using a magnetic stirrer for 6 hours to ensure that all the powders were completely dissolved. After the stirring was completed, the solution was left to stand for at least 2 hours to allow the insoluble impurities to settle for later use.

[0106] s3: CVD epitaxial growth

[0107] The sapphire was fixed in the upper connecting rod, and the height of the upper connecting rod was adjusted to ensure that the distance between the substrate and the reaction source was accurately controlled at 15 mm. The heating temperature of the reaction chamber was set to 600°C, and after reaching the target temperature, the argon flow rate was set to 2 L / min and the oxygen flow rate was set to 0.3 L / min, which were accurately controlled by mass flow controllers.

[0108] Before starting the atomization, the gas circuit was kept open for at least 1 hour to ensure that the gas filled the entire reaction chamber. Then, the precursor solution with a Ge doping concentration of 1% was added to the ultrasonic atomization tank and the atomization was started, and the gas transported the atomized liquid to the reaction chamber for deposition growth for 4 hours.

[0109] epsilon For the double-layer Ge-doped Figure 1 Ga2O3 film prepared in Example 3, the (002) plane XRD rocking curve of the Ga2O3 film was at a low level of 0.35°, confirming that a high-quality Ga2O3 film was obtained. epsilon

[0110] ​epsilon The double-layer Ge-doped material prepared in Example 3 Figure 2 SEM image of the Ga2O3 thin film. The image shows a clear boundary between the substrate and the film, and the film is uniform with a thickness of 5 μm, indicating a relatively fast growth rate of 1.25 μm / h.

[0111] epsilon This is for the preparation of bilayer Ge doped material in Example 3. Figure 3 XPS Ge3d images of Ga2O3 thin films, from epsilon The presence of Ge elements is clearly visible, and analysis reveals double-layered Ge doping. Figure 3 The Ge content on the surface of the Ga2O3 thin film is 4%, which proves that 80% efficient doping has been achieved.

[0112] epsilon The diagram below shows the structure of the ultraviolet detector provided in Embodiment 1 of the present invention. The device has 13 pairs of interdigitated electrodes, each 500 μm in length, with a spacing of 10 μm between the electrodes, and an effective irradiation area of ​​1.25 × 10⁻⁶. -3 cm 2 .

[0113] Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 The images show the IV test patterns of the devices prepared in Examples 1-3 and Comparative Examples 1-3, respectively. It can be seen that the bilayer Ge-doped devices prepared in Examples 1-3... Figure 10 epsilon Ga2O3 thin films exhibit higher photocurrent, with a photo-dark current ratio reaching 10. 7 Meanwhile, Examples 1, 2, and 3 exhibit responsivity as high as 132.4, 407.2, and 508 A / W, respectively, and a response time of 2.62 × 10⁻⁶. 16 9.59×10 16 1.77×10 16 Jones's detectivity. In comparison, the detectivity of Comparative Examples 1-3 were 4.53, 38.68, and 0.59 A / W, respectively, and the responsivity was 8.73 × 10⁻⁶. 13 4.89×10 12 7.26×10 12 Jones.

[0114] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A kind ε The method for preparing Ga2O3 thin films is characterized by: Includes the following steps: The cleaned and pretreated substrate is heated to 550-610℃, and a mixture of carrier gas and dilution gas is introduced into it for a set time. Then, a lightly doped gallium oxide precursor solution with a Ge doping concentration of 1-5% is atomized and added, and the low-doped precursor is epitaxially grown. ε -Ga2O3 thin film; After growth, the temperature inside the reaction chamber is heated to 620-700℃, and the atmosphere is kept constant. A highly doped gallium oxide precursor solution with a Ge doping concentration of 5-8% is then atomized and added. The highly doped epitaxial growth is then carried out. ε -Ga2O3 thin film.

2. As described in claim 1 ε The method for preparing Ga2O3 thin films is characterized by: The cleaning pretreatment method is as follows: the substrate is ultrasonically cleaned sequentially with isopropanol, ethanol and deionized water, and then dried with nitrogen.

3. As described in claim 1 ε The method for preparing Ga2O3 thin films is characterized by: In the low-doped gallium oxide precursor solution and / or the high-doped gallium oxide precursor solution, the concentration of gallium acetylacetonate is 0.01-0.1 mol / L.

4. As described in claim 1 ε The method for preparing Ga2O3 thin films is characterized by: The Ge dopant is germanium iodide.

5. The method according to claim 1 ε The method for preparing Ga2O3 thin films is characterized by: Epitaxial low doping ε The curing time for Ga2O3 thin films is 1.5-2.5 h; epitaxial high-doping ε The curing time for the Ga2O3 thin film is 1.5-2.5 h; Epitaxial low doping ε The temperature for Ga2O3 thin films is 580-610℃; epitaxial high-doping ε - The temperature range for Ga2O3 thin films is 630-660℃.

6. The method according to claim 1 ε The method for preparing Ga2O3 thin films is characterized by: The carrier gas is argon, and the diluent gas is oxygen.

7. A kind ε -Ga2O3 thin film, characterized in that: It is prepared by any one of the preparation methods described in claims 1-6.

8. The method according to claim 7 ε -Ga2O3 thin film, characterized in that: ε The thickness of the Ga2O3 film is 3-7 μm, and the half-width at half-maximum of the rocking curve is 0.53°.

9. A metastable gallium oxide ultraviolet detector, characterized in that: Including the substrate and the low-doped material of claim 1 attached to the surface of the substrate. ε -Ga2O3 thin film and attached to low-doped ε -The highly doped Ga2O3 thin film surface as described in claim 1 ε -Ga2O3 thin film, highly doped ε - An electrode is attached to the surface of the Ga2O3 thin film.

10. The metastable gallium oxide ultraviolet detector according to claim 9, characterized in that: The electrode is a titanium-gold electrode, with a titanium layer thickness of 15-25nm and a gold layer thickness of 20-40nm.

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