A method for preparing a <010> preferentially oriented beta-Ga2O3 film
By using laser chemical vapor deposition on a quartz glass substrate and adjusting the deposition parameters, it was prepared... <010> Preferred-oriented β-Ga2O3 films solve the problem of difficult preparation on heterogeneous substrates, realize the preparation of low-cost, highly oriented films, and broaden the application range.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WUHAN UNIV OF TECH
- Filing Date
- 2022-10-19
- Publication Date
- 2026-04-10
AI Technical Summary
Current technology has not yet been able to fabricate on heterogeneous substrates. <010> Preferred orientation of β-Ga2O3 polycrystalline thin films limits their application range and increases costs.
β-Ga₂O₃ thin films were prepared on quartz glass substrates using laser chemical vapor deposition (laser chemical vapor deposition). The orientation of the films was controlled by adjusting deposition parameters such as temperature, pressure, and laser wavelength. <010> A dense structure composed of preferentially oriented β-Ga2O3 columnar crystals.
Successfully fabricated on a low-cost quartz glass substrate <010> Preferred orientation of β-Ga2O3 polycrystalline thin films broadens their application range.
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Figure CN116516315B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of single crystal growth technology, specifically relating to a... <010> A method for preparing preferentially oriented β-Ga2O3 thin films. Background Technology
[0002] β-Ga₂O₃ is a novel wide-bandgap semiconductor material with a bandgap of approximately 4.9 eV. This large bandgap enables β-Ga₂O₃ to be used in the fabrication of high-voltage, high-power, low-loss power devices and deep-ultraviolet optoelectronic devices. Furthermore, β-Ga₂O₃ is widely used in high-temperature gas sensing, photoelectrolysis, and LED lighting. β-Ga₂O₃ is a monoclinic crystal with a space group of C² / m and a lattice constant of [missing value]. With α = β = 90° and γ = 103.82°, the extreme asymmetry in its structure leads to anisotropy in its properties. For example, β-Ga₂O₃ single crystals... <010> Thermal conductivity in the directional direction (27.0 W / m²) -1 K -1 The conductivity is approximately 2 to 3 times that in other directions, and the electrical conductivity (38Ω) is... -1 cm -1 Approximately <001> Twenty times greater in the direction, the two-photon absorption coefficient TPA (1.2 cm / GW) is much higher than... The two-photon absorption coefficient of β-Ga2O3 is 0.6 cm / GW. Currently, the cost of high-quality β-Ga2O3 single crystals remains high, while polycrystalline thin films with preferred orientation can also exhibit anisotropic characteristics. Therefore, research on the theory of preferred orientation in polycrystalline materials can not only broaden the application range of polycrystalline materials, but also reduce the demand for expensive single crystals.
[0003] Current research often uses single-crystal substrates with low mismatch rates to restrict the orientation of crystalline thin films, and high-quality films have been successfully fabricated on heterogeneous substrates. <100> , <001> and Oriented β-Ga2O3 thin films. However, <010> Crystal plane symmetry is low, and <010> Heterogeneous substrates conforming to epitaxial relationships for oriented β-Ga₂O₃ thin films have not yet been discovered, while homogeneous substrates are expensive and have poor electrical and thermal conductivity; in addition, <010> The surface energy of the surface is relatively high (approximately 2.78 J / m). 2), at the deposition temperature (less than 1100 DEG C) of the traditional preparation method, the reaction atoms cannot obtain enough energy to arrange along the high-energy surface to form <010> preferred orientation. Based on the above reasons, no researchers have prepared <010> preferred orientation of the beta-Ga2O3 polycrystalline thin film on the hetero-substrate, which limits the development of the high-orientation beta-Ga2O3 polycrystalline thin film. Therefore, exploring a method for preparing <010> preferred orientation of the beta-Ga2O3 polycrystalline thin film has very important significance for widening its application range. SUMMARY
[0004] The technical problem to be solved by the present application is to provide a method for preparing a <010> preferred orientation of a beta-Ga2O3 thin film.
[0005] The technical problem to be solved by the present application is to provide a method for preparing a <010> preferred orientation of a beta-Ga2O3 thin film.
[0006] To solve the above technical problems, the technical scheme provided by the present application is:
[0007] The present application provides a method for preparing a <010> preferred orientation of a beta-Ga2O3 thin film, and the specific steps are as follows:
[0008] 1) Put the precursor into the raw material tank of the cold-wall laser chemical vapor deposition equipment, then put the glass substrate into the deposition cavity after pretreatment, adjust the position of the glass substrate to make it in the laser coverage range, and vacuumize the deposition cavity to below 10 Pa;
[0009] 2) introduce the dilution gas into the deposition cavity to reach the deposition pressure, close the dilution gas, then heat the precursor in the raw material tank to the sublimation temperature, open the laser to irradiate the surface of the glass substrate, make the glass substrate reach the deposition temperature, at the same time, introduce the carrier gas and the reaction gas into the deposition cavity for deposition, then close the carrier gas, the reaction gas and the laser in turn after the deposition is completed, and naturally cool to room temperature, so as to deposit the <010> preferred orientation of the beta-Ga2O3 thin film on the glass substrate.
[0010] According to the above scheme, the precursor in step 1) is powder-shaped gallium acetylacetonate (Ga(acac)3). The sublimation temperature of the precursor gallium acetylacetonate is 200 DEG C.
[0011] According to the above scheme, the glass substrate in step 1) is a quartz glass substrate, and the pretreatment method of the glass substrate is: ultrasonic cleaning the glass substrate in acetone and ethanol in turn, then rinsing with deionized water, and finally blowing the surface of the glass substrate dry with N2.
[0012] According to the above scheme, the dilution gas in step 2) is Ar, and the purity of Ar is more than 99.999 vol%, and the flow rate of Ar is 100-500 sccm.
[0013] According to the above scheme, the deposition pressure in step 2) is 100-10000 Pa.
[0014] According to the above scheme, the laser wavelength in step 2) is 800-1200 nm.
[0015] According to the above scheme, the carrier gas in step 2) is Ar, the flow rate is 100-200 sccm, and the purity is greater than 99.999 vol%; the reaction gas is O2, the flow rate is 100-500 sccm, and the purity is greater than 99.999 vol%.
[0016] According to the above scheme, the deposition process conditions in step 2) are: deposition temperature 850-1100℃, deposition time 5-20 min.
[0017] According to the above scheme, the deposition growth rate of the β-Ga2O3 thin film in step 2) is 10-45 μm / h.
[0018] The present application also includes the <010> preferentially oriented β-Ga2O3 thin film obtained according to the above preparation method, which is a dense structure composed of <010> preferentially oriented β-Ga2O3 columnar crystals. The thickness of the thin film can be adjusted according to the deposition time.
[0019] The present application selects a quartz glass substrate and uses laser chemical vapor deposition (LCVD) to prepare a highly oriented β-Ga2O3 polycrystalline thin film, and controls the orientation of the β-Ga2O3 crystal by adjusting parameters such as pressure and temperature. Laser chemical vapor deposition is used because the excitation of a high-energy laser beam can accelerate the thermodynamic and kinetic processes of reaction gas decomposition, adsorption, and film formation. Under different deposition conditions, the growth rate (i.e. formation energy) of different crystal faces is different, and the high-speed growth of the crystallographic crystal face will quickly cover other oriented crystal faces. At this time, the result of the competition between multiple crystal faces is that the crystal grows along a certain specific crystal direction. Experimental results show that when the quartz glass substrate is selected and the deposition temperature is between 850-1100℃, the thin film is composed of a large number of <010> preferentially oriented β-Ga2O3 columnar crystals to form a high-density structure.
[0020] The present application has the beneficial effect that: the present application uses laser chemical vapor deposition to control the orientation of the thin film by adjusting experimental parameters, and successfully prepares a <010> preferentially oriented β-Ga2O3 polycrystalline thin film on the surface of a low-cost quartz glass substrate, which has great significance for widening the application range of the β-Ga2O3 polycrystalline thin film. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 The XRD pattern of the <010> oriented β-Ga2O3 thin film prepared in Example 1 of the present application;
[0022] Figure 2 The one prepared in Example 1 <010> SEM image of oriented β-Ga2O3 thin film;
[0023] Figure 3 The one prepared in Example 2 <010> XRD pattern of oriented β-Ga2O3 thin film;
[0024] Figure 4 The one prepared in Example 2 <010> SEM image of oriented β-Ga2O3 thin film;
[0025] Figure 5 The product prepared for Comparative Example 1 XRD pattern of oriented β-Ga2O3 thin film;
[0026] Figure 6 The product prepared for Comparative Example 1 SEM image of oriented β-Ga2O3 thin film;
[0027] Figure 7 The image shows the XRD pattern of the non-preferred-orientation β-Ga2O3 thin film prepared in Comparative Example 2.
[0028] Figure 8 The image shows a SEM image of the non-preferred-orientation β-Ga2O3 thin film prepared in Comparative Example 2. Detailed Implementation
[0029] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.
[0030] Example 1
[0031] A sort of <010> The specific steps for preparing the preferred-oriented β-Ga2O3 thin film material are as follows:
[0032] 1) The quartz glass substrate (10mm×10mm×1mm) was ultrasonically cleaned in acetone for 10 minutes, ultrasonically cleaned in ethanol for 5 minutes, rinsed with deionized water, and finally dried with N2.
[0033] 2) Grind 0.5g of gallium acetylacetonate precursor into powder with a particle size of 1-10μm, place it in the raw material tank of the cold wall laser chemical vapor deposition equipment, put the cleaned quartz glass substrate into the deposition chamber of the laser chemical vapor deposition equipment, adjust the position of the quartz glass substrate so that it is within the laser coverage area, and evacuate the deposition chamber to 10Pa and maintain it for 5min.
[0034] 3) After the deposition chamber is filled with dilution gas Ar with a flow rate of 500 sccm and a purity of 99.999 vol%, the deposition pressure is 7000 Pa, the dilution gas is turned off, the raw material tank is heated to 200°C, the laser irradiates the quartz glass substrate with a wavelength of 808 nm, the surface temperature of the quartz glass substrate is raised to 850°C, and the deposition is carried out in the deposition chamber by introducing carrier gas Ar and reaction gas O2, wherein the flow rate of Ar is 200 sccm, the purity of Ar is 99.999 vol%, the flow rate of O2 is 200 sccm, the purity of O2 is 99.999 vol%, the deposition time is 10 min, the carrier gas Ar and O2 are turned off in sequence after the deposition, and then the laser is turned off. The quartz glass substrate is naturally cooled to room temperature, and a <010> preferentially oriented β-Ga2O3 thin film is obtained on the surface of the quartz glass substrate.
[0035] The X-ray diffraction pattern and the field emission scanning image of the β-Ga2O3 thin film material prepared in this example are shown in Figure 1 and Figure 2 . Figure 1 The X-ray diffraction pattern of the β-Ga2O3 thin film is compared with the standard PDF card. The (010) diffraction peak at 61° is higher than other peaks, while the strongest peak in the standard PDF card (JCPDS 76-0573) is the (111) diffraction peak at 35.2°, which means that the β-Ga2O3 thin film prepared in this example is significantly <010> preferentially oriented. Figure 2 (a) is the surface morphology of the β-Ga2O3 thin film, Figure 2 (b) is the cross-sectional morphology of the β-Ga2O3 thin film. It can be seen that the thin film material prepared in this example is a dense structure composed of large-size β-Ga2O3 columnar crystals, which is one of the typical characteristics of highly oriented polycrystalline thin films. The thickness of the thin film is 6.2 μm, and the growth rate is 38.4 μm / h.
[0036] Example 2
[0037] A <010> preferentially oriented β-Ga2O3 thin film material, and the specific steps of the preparation method are as follows:
[0038] 1) The quartz glass substrate (10 mm x 10 mm x 1 mm) is sequentially ultrasonically cleaned in acetone for 10 min, ultrasonically cleaned in ethanol for 5 min, then rinsed with deionized water, and finally dried with N2;
[0039] 2) The precursor 0.5 g of gallium acetylacetonate is ground into a powder with a particle size of 1-10 μm, and placed in the raw material tank of the cold-wall laser chemical vapor deposition equipment. The cleaned quartz glass substrate is placed in the deposition chamber of the laser chemical vapor deposition equipment, the position of the quartz glass substrate is adjusted so that it is within the laser coverage, and the deposition chamber is evacuated to 10 Pa and maintained for 5 min.
[0040] 3) After the deposition chamber is filled with dilution gas Ar with a flow rate of 500 sccm and a purity of 99.999 vol%, the deposition pressure is 7000 Pa, the dilution gas is turned off, the raw material tank is heated to 200°C, the laser irradiates the quartz glass substrate, the laser output wavelength is 808 nm, the quartz glass substrate surface is heated to 1100°C, the deposition chamber is filled with carrier gas Ar and reaction gas O2 for deposition, the flow rate of Ar is 200 sccm, the purity of Ar is 99.999 vol%, the flow rate of O2 is 200 sccm, the purity of O2 is 99.999 vol%, the deposition time is 10 min, the carrier gas Ar and O2 are turned off in sequence after the deposition is completed, and then the laser is turned off. The quartz glass substrate is naturally cooled to room temperature, and a <010> preferentially oriented β-Ga2O3 thin film is obtained on the surface of the quartz glass substrate.
[0041] The X-ray diffraction pattern and the field emission scanning image of the β-Ga2O3 thin film material prepared in the example are shown in Figure 3 and Figure 4 . Figure 3 The X-ray diffraction pattern of the β-Ga2O3 thin film is compared with the standard PDF card. The β-Ga2O3 thin film prepared in the example is similar to that in Example 1, and both exhibit a significant <010> preferential orientation. Figure 4 (a) is the surface morphology of the β-Ga2O3 thin film, and the grain Figure 4 (b) is the cross-sectional morphology of the β-Ga2O3 thin film. As can be seen from the figure, the thin film material prepared in the example is also a dense structure composed of β-Ga2O3 columnar crystals, but compared with Example 1, the higher growth temperature makes the size of the crystal grains increase. The thickness of the β-Ga2O3 thin film prepared in the example is 6.8 μm, and the growth rate is 41.1 μm / h.
[0042] Comparative Example 1
[0043] The β-Ga2O3 thin film material is prepared by using a MgO substrate, and the specific steps are as follows:
[0044] 1) The <111>-MgO substrate (10 mm x 10 mm x 0.5 mm) is sequentially ultrasonically cleaned in acetone for 10 min, ultrasonically cleaned in ethanol for 5 min, then rinsed with deionized water, and finally dried with N2;
[0045] 2) The precursor 0.5 g of gallium acetylacetonate is ground into a powder with a particle size of 1-10 μm, which is placed in the raw material tank of the cold-wall laser chemical vapor deposition equipment. The cleaned MgO substrate is placed in the deposition chamber of the laser chemical vapor deposition equipment, the position of the MgO substrate is adjusted so that it is located in the laser coverage range, the deposition chamber is vacuumed to 10 Pa and maintained for 5 min;
[0046] 3) Diluent gas Ar is introduced into the deposition chamber at a flow rate of 500 sccm and a purity of 99.999 vol%. The deposition pressure is 7000 Pa. The diluent gas is then turned off. Simultaneously, the raw material tank is heated to 200°C, and the laser is turned on to irradiate the MgO substrate at a wavelength of 808 nm, raising the surface temperature of the MgO substrate to 1100°C. Carrier gas Ar and reactive gas O2 are then introduced into the deposition chamber for deposition at a flow rate of 200 sccm and a purity of 99.999 vol%. The O2 flow rate is also 200 sccm and a purity of 99.999 vol%. The deposition time is 10 min. After deposition, the carrier gases Ar and O2 are turned off sequentially, followed by the laser. The MgO substrate is allowed to cool naturally to room temperature, resulting in a deposit on the MgO substrate surface. Preferred orientation of β-Ga2O3 thin film.
[0047] The X-ray diffraction pattern and field emission scanning imaging pattern of the β-Ga2O3 thin film material prepared in this comparative example are shown below. Figure 5 and Figure 6 As shown. Figure 5 This is a comparison of the X-ray diffraction pattern of the β-Ga₂O₃ thin film with the standard PDF card, where the pattern located at 18.9° is shown. The diffraction peak is the strongest, located at 38.2°. The diffraction peak is the second strongest peak, which means that the β-Ga2O3 thin film prepared in this comparative example exhibits significant... The best approach. Figure 6 The surface and cross-sectional morphology of the β-Ga₂O₃ thin film are shown. It can be observed that the β-Ga₂O₃ thin film consists of large frustum-shaped β-Ga₂O₃ grains, with a distinct layered structure on both the surface and cross-section. The growth rate of the β-Ga₂O₃ thin film prepared in this comparative example is 30.48 μm / h.
[0048] Comparative Example 2
[0049] β-Ga2O3 thin films were prepared at a deposition temperature of 800℃, and the specific steps are as follows:
[0050] 1) The quartz glass substrate (10mm×10mm×1mm) was ultrasonically cleaned in acetone for 10 minutes, ultrasonically cleaned in ethanol for 5 minutes, rinsed with deionized water, and finally dried with N2.
[0051] 2) Grind 0.5g of gallium acetylacetonate precursor into powder with a particle size of 1-10μm, place it in the raw material tank of the cold wall laser chemical vapor deposition equipment, put the cleaned quartz glass substrate into the deposition chamber of the laser chemical vapor deposition equipment, adjust the position of the quartz glass substrate so that it is within the laser coverage area, and evacuate the deposition chamber to 10Pa and maintain it for 5min.
[0052] 3) After the deposition chamber is filled with dilution gas Ar with a flow rate of 500 sccm and a purity of 99.999 vol%, the deposition pressure is set to 7000 Pa, the dilution gas is turned off, the raw material tank is heated to 200°C, the laser irradiates the quartz glass substrate with a wavelength of 808 nm, the surface of the quartz glass substrate is heated to 800°C, and the deposition chamber is filled with carrier gas Ar and reaction gas O2 for deposition, the flow rate of Ar is 200 sccm, the purity of Ar is 99.999 vol%, the flow rate of O2 is 200 sccm, the purity of O2 is 99.999 vol%, the deposition time is 10 min, and after deposition, the carrier gas Ar and O2 are turned off in sequence, the laser is turned off, and the quartz glass substrate is naturally cooled to room temperature, thereby obtaining a non-preferred orientation β-Ga2O3 film on the surface of the quartz glass substrate.
[0053] The X-ray diffraction pattern and the field emission scanning image of the β-Ga2O3 film material prepared in the present comparative example are shown in Figure 7 and Figure 8 As shown in Figure 5 , the X-ray diffraction pattern of the β-Ga2O3 film shows typical polycrystalline characteristics without obvious preferred orientation. Figure 8 (a) and Figure 8 (b) are the surface and cross-sectional morphology of the β-Ga2O3 film, respectively, and it can be seen that the β-Ga2O3 film material prepared at a low deposition temperature in the present comparative example is a dense structure composed of a large number of flat β-Ga2O3 platelet-shaped small particles without preferred orientation.
[0054] The above specific examples further illustrate the purpose, technical solutions, and beneficial effects of the present application. For those skilled in the art, the present application can be modified and changed in various ways, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be within the scope of protection of the present application.
Claims
1. A kind <010> A method for preparing preferentially oriented β-Ga2O3 thin films, characterized in that, The specific steps are as follows: 1) Place 0.5g of precursor in the raw material tank of the cold-wall laser chemical vapor deposition equipment. The precursor is powdered gallium acetylacetonate. Then, after pretreatment, place the glass substrate into the deposition chamber. The glass substrate is a quartz glass substrate. Adjust the position of the glass substrate so that it is within the laser coverage area, and evacuate the deposition chamber to below 10 Pa. 2) A dilution gas is introduced into the deposition chamber to reach the deposition pressure. The dilution gas is then shut off. The precursor in the raw material tank is heated to the sublimation temperature. The laser is then turned on to irradiate the surface of the glass substrate, bringing it to the deposition temperature. Simultaneously, a carrier gas and a reactive gas are introduced into the deposition chamber for deposition. The reactive gas is O2, with a flow rate of 200 sccm. The deposition temperature is 850~1100℃. After deposition, the carrier gas, reactive gas, and laser are sequentially shut off, and the substrate is allowed to cool naturally to room temperature, thus depositing the desired product on the glass substrate. <010> Preferred orientation of β-Ga2O3 thin film.
2. As described in claim 1 <010> A method for preparing preferentially oriented β-Ga2O3 thin films, characterized in that, Step 1) The pretreatment method for the glass substrate is as follows: the glass substrate is placed in acetone and ethanol in sequence for ultrasonic cleaning, then rinsed with deionized water, and finally the surface of the glass substrate is dried with N2.
3. As described in claim 1 <010> A method for preparing preferentially oriented β-Ga2O3 thin films, characterized in that, Step 2) The diluting gas is Ar, with a purity of 99.999 vol% or higher and a flow rate of 100~500 sccm.
4. As described in claim 1 <010> A method for preparing preferentially oriented β-Ga2O3 thin films, characterized in that, Step 2) The deposition pressure is 100~10000Pa.
5. The method according to claim 1 <010> A method for preparing preferentially oriented β-Ga2O3 thin films, characterized in that, Step 2) The laser wavelength is 800~1200nm.
6. The method according to claim 1 <010> A method for preparing preferentially oriented β-Ga2O3 thin films, characterized in that, Step 2) The carrier gas is Ar, with a flow rate of 100~200 sccm and a purity of 99.999 vol% or higher, and the reaction gas has a purity of 99.999 vol% or higher.
7. The method according to claim 1 <010> A method for preparing preferentially oriented β-Ga2O3 thin films, characterized in that, Step 2) Deposition process conditions: deposition time 5~20 min.
8. The method according to claim 1 <010> A method for preparing preferentially oriented β-Ga2O3 thin films, characterized in that, Step 2) The β-Ga2O3 thin film deposition growth rate is 10~45μm / h.
9. The preparation method according to any one of claims 1-8 yields... <010> Preferred-oriented β-Ga2O3 thin films, characterized in that, The thin film is <010> A dense structure composed of preferentially oriented β-Ga2O3 columnar crystals.