Preparation method of silicon carbide-based lithium niobate film
The lithium niobate layer is grown on the silicon carbide substrate through magnetron sputtering process and annealing treatment, which solves the problems of complex and high cost in the ion slicing process in the prior art, and achieves low-cost and high-quality silicon carbide-based lithium niobate film preparation.
Patent Information
- Application Number
- CN202510163051.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-14
- Publication Date
- 2025-06-06
AI Technical Summary
The prior art transfer bonding of lithium niobate film to a silicon carbide substrate through an ion slicing process, which is complex and costly, limiting the application of lithium niobate on silicon carbide.
The lithium niobate layer was grown on the silicon carbide substrate by magnetron sputtering process and annealed at a temperature of 600-900°C to improve the crystallization quality.
The high-quality silicon carbide-based lithium niobate film was achieved at low cost, which simplified the process route, reduced the preparation difficulty, and controlled the stoichiometric ratio of lithium niobate.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of semiconductors, and in particular relates to a method for preparing a silicon carbide-based lithium niobate film. Background Art
[0002] With the rise of the Internet of Things and the new era of 5G, people have put forward higher requirements for signal propagation, exploration and modulation. Photons have a faster response speed than electrons and have higher capacity and lower crosstalk in the field of information propagation, which makes optical integrated devices gradually become a hot topic of research.
[0003] Lithium niobate on insulator (LNOI) has a strong limiting effect on the light field due to its extremely thin lithium niobate film thickness, which can improve the efficiency of electro-optic modulation and has important applications in integrated electro-optic modulation devices and high-speed electro-optic switches. Silicon carbide (SiC) has good thermal conductivity. Choosing silicon carbide as the insulating substrate in LNOI can increase the heat dissipation during the application of the device. And as one of the representatives of the third generation of semiconductors, silicon carbide has a wide range of applications in the field of power electronics. It is relatively easy to integrate lithium niobate on silicon carbide into silicon carbide integrated devices, which helps to realize multifunctional silicon carbide integrated devices and has important research value.
[0004] The prior art transfers and bonds a lithium niobate film to a silicon carbide substrate through an ion slicing process. However, the ion slicing process is complex and costly, which greatly limits the application of lithium niobate on silicon carbide. Summary of the invention
[0005] In order to solve the above problems existing in the prior art, the present invention provides a method for preparing a silicon carbide-based lithium niobate film. The technical problem to be solved by the present invention is achieved by the following technical solution:
[0006] The present invention provides a method for preparing a silicon carbide-based lithium niobate film, comprising the following steps:
[0007] S1: growing a lithium niobate layer on the surface of a silicon carbide substrate by magnetron sputtering;
[0008] S2: Annealing is performed at a temperature of 600 to 900° C., and after cooling, a silicon carbide-based lithium niobate film is obtained.
[0009] In one achievable manner, the magnetron sputtering process includes: a laser magnetron sputtering process, a high-power pulsed magnetron sputtering process, an ion beam enhanced magnetron sputtering process or a radio frequency magnetron sputtering process.
[0010] In one achievable manner, the magnetron sputtering process is a radio frequency magnetron sputtering process; the growth temperature of the radio frequency magnetron sputtering process is 500-700° C., the sputtering power is 50-60 W, and the sputtering time is 120-240 min.
[0011] In one achievable manner, the sputtering atmosphere of the radio frequency magnetron sputtering process is argon or nitrogen.
[0012] In a feasible manner, the annealing time is 30 to 120 minutes, the annealing atmosphere is argon, and the heating rate is 5 to 15° C. / min.
[0013] In one achievable manner, a crystal plane of the silicon carbide substrate is a (0001) plane.
[0014] In one achievable manner, the annealing device includes: a tubular annealing furnace, a box annealing furnace, a vacuum annealing furnace or an atmosphere annealing furnace.
[0015] In one possible implementation, S1 also includes:
[0016] The silicon carbide substrate is pretreated to remove contamination and damage on the surface of the silicon carbide substrate.
[0017] In one achievable manner, the pretreatment includes: chemical mechanical polishing, cleaning and hydrogen etching performed in sequence.
[0018] In one achievable manner, the temperature of the hydrogen etching is 1400-1600° C., and the time is 20-30 min.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] The method for preparing a silicon carbide-based lithium niobate film provided by the present invention grows a lithium niobate layer on the surface of a silicon carbide substrate by a magnetron sputtering process, and improves its crystal quality by annealing, thereby realizing the preparation of a high-quality silicon carbide-based lithium niobate film by a magnetron sputtering process, effectively reducing the manufacturing cost of the silicon carbide-based lithium niobate film, and providing a method for preparing a high-quality silicon carbide-based lithium niobate film at a low cost. The process route of the magnetron sputtering combined with annealing provided by the present invention is simple, and allows the stoichiometric ratio of lithium niobate to be controlled during the magnetron sputtering process, and can achieve a relatively low deposition temperature, reducing the difficulty of preparing the silicon carbide-based lithium niobate film. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 It is a flow chart of the steps of a method for preparing a silicon carbide-based lithium niobate film provided in an embodiment of the present invention.
[0022] Figure 2a to 2eThis is the Raman spectrum of silicon carbide-based lithium niobate film;
[0023] Figure 3a to 3e This is the X-ray diffraction (XRD) pattern of silicon carbide-based lithium niobate film. DETAILED DESCRIPTION
[0024] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.
[0025] See also Figure 1 , Figure 1 It is a flow chart of the steps of a method for preparing a silicon carbide-based lithium niobate film provided in an embodiment of the present invention.
[0026] This embodiment provides a method for preparing a silicon carbide-based lithium niobate film, comprising the following steps:
[0027] S1: A lithium niobate layer is grown on the surface of a silicon carbide substrate by magnetron sputtering.
[0028] Specifically, the magnetron sputtering process includes: laser magnetron sputtering process, high power pulse magnetron sputtering process, ion beam enhanced magnetron sputtering process or radio frequency magnetron sputtering process.
[0029] In this embodiment, the magnetron sputtering process is a radio frequency magnetron sputtering process, the growth temperature of the radio frequency magnetron sputtering process is 500-700°C, the sputtering power is 50-60W, and the sputtering time is 120-240min. The sputtering atmosphere of the radio frequency magnetron sputtering process is argon or nitrogen. The target material of the magnetron sputtering process is a lithium niobate target material. The vacuum degree of the sputtering chamber is 10 -4 ~10 - 5 Pa. Exemplarily, the growth temperature of the RF magnetron sputtering process is 500° C., 550° C., 600° C., 650° C. or 700° C., the sputtering power is 50 W, 55 W or 60 W, and the sputtering time is 120 min, 150 min, 180 min, 200 min, or 240 min.
[0030] In one possible implementation, S1 also includes:
[0031] The silicon carbide substrate is pretreated to remove contamination and damage on the surface of the silicon carbide substrate.
[0032] In this embodiment, the pretreatment includes: chemical mechanical polishing, cleaning and hydrogen etching performed in sequence. The temperature of hydrogen etching is 1400-1600° C., and the time is 20-30 minutes. The crystal plane of the silicon carbide substrate is the (0001) plane. Exemplarily, the temperature of hydrogen etching is 1600° C., and the time is 25 minutes.
[0033] In this embodiment, the specific steps of cleaning are:
[0034] The silicon carbide substrate is cleaned using concentrated sulfuric acid, aqua regia, hydrofluoric acid and deionized water in sequence.
[0035] S2: Annealing is performed at a temperature of 600 to 900° C., and after cooling, a silicon carbide-based lithium niobate film is obtained.
[0036] Specifically, the annealing time is 30 to 120 minutes, the annealing atmosphere is argon, and the heating rate is 5 to 15°C / min. Optionally, the annealing device includes: a tubular annealing furnace, a box annealing furnace, a vacuum annealing furnace or an atmosphere annealing furnace. Exemplarily, the heating rate is 5°C / min, 10°C / min or 15°C / min.
[0037] Specifically, due to the large lattice constant mismatch between lithium niobate and SiC, the crystal quality of lithium niobate directly grown on SiC is poor and difficult to meet application requirements. Therefore, the prior art prepares silicon carbide-based lithium niobate films by ion slicing. In this embodiment, a lithium niobate layer is grown on the surface of a (0001) silicon carbide substrate by a magnetron sputtering process, and by observing the crystal quality of the lithium niobate layer grown by the magnetron sputtering process, the crystal state of the lithium niobate layer on silicon carbide obtained by magnetron sputtering is improved by annealing, thereby achieving high-quality silicon carbide-based lithium niobate films by magnetron sputtering, effectively reducing the manufacturing cost of silicon carbide-based lithium niobate films. In addition, the process route of magnetron sputtering combined with annealing provided in this embodiment is simple, and allows the stoichiometric ratio of lithium niobate to be controlled during the magnetron sputtering process, which can achieve a relatively low deposition temperature and reduce the difficulty of preparing silicon carbide-based lithium niobate films.
[0038] Furthermore, during the annealing process, the lithium niobate film undergoes recrystallization, the grains aggregate, and the grain size increases. A lower annealing temperature can reduce the stress in the crystal and improve the crystallization performance of the film. A higher annealing temperature helps to eliminate defects in the crystal and improve the optical and electrical properties of the film. Therefore, when selecting the annealing temperature, it is necessary to comprehensively consider the application requirements of the film and the limitations of the preparation process. In the preparation method provided in this embodiment, the annealing temperature is 600-900°C. When the annealing temperature is lower than 600°C, the temperature is too low and lithium niobate cannot be recrystallized, and the effect of improving the crystal quality cannot be achieved. When the annealing temperature is higher than 900°C, lithium niobate will decompose. The remaining process parameters can be selected according to actual production needs.
[0039] In this embodiment, the specific operation of S2 is:
[0040] Clean the interior of the annealing furnace to prevent residual substances in the annealing furnace from contaminating the film. Put the sample obtained in S1 into the cleaned annealing furnace and evacuate the annealing furnace to 10 -4 ~10 -5 Pa to reduce the influence of air on the annealing process. Then, argon or nitrogen is passed into the annealing furnace at 50-90 sccm for 5 minutes to further avoid the influence of air on the annealing process. After passing argon or nitrogen, the annealing time, annealing temperature, annealing atmosphere and heating rate are set, and the various parameters in the annealing are controlled by manual operation or computer setting program. After the annealing is completed, the sample is taken out of the annealing furnace after natural cooling to obtain a silicon carbide-based lithium niobate film.
[0041] Furthermore, under the process conditions of a RF magnetron sputtering process with a growth temperature of 600°C, a sputtering power of 50 W, a sputtering time of 240 min, an argon atmosphere, and a sputtering pressure of 5 mTorrr, a plurality of lithium niobate layers located on the surface of the silicon carbide substrate were grown, and argon was used as the annealing atmosphere. Annealing was performed under different annealing parameters to obtain a plurality of silicon carbide-based lithium niobate films, which are recorded as Example 1, Example 2, Example 3, Example 4, and Example 5. The specific annealing parameters of Example 1, Example 2, Example 3, Example 4, and Example 5 are shown in Table 1, and the obtained silicon carbide-based lithium niobate films were characterized to further illustrate the preparation method of the silicon carbide-based lithium niobate film provided in this embodiment.
[0042] Table 1: Annealing parameters of Examples 1 to 5
[0043] Annealing time Annealing temperature Heating rate Argon flow rate Example 1 120min 600℃ 10℃ / min 90sccm Example 2 120min 850℃ 10℃ / min 90sccm Example 3 120min 900℃ 10℃ / min 90sccm Example 4 30min 850℃ 10℃ / min 90sccm Example 5 60min 850℃ 10℃ / min 90sccm
[0044] The results of characterization of the silicon carbide-based lithium niobate films obtained in Examples 1 to 5 are as follows: Figure 2a to 2e and 3a to 3e, where: Figure 2a to 2e The Raman spectra of the silicon carbide-based lithium niobate films obtained in Examples 1 to 5 are respectively, Figure 3a to 3e They are X-ray diffraction (XRD) patterns of silicon carbide-based lithium niobate films obtained in Examples 1 to 5, respectively. Within the process parameter range of annealing temperature of 600 to 900°C and annealing time of 30 to 120 minutes, the crystal quality of the obtained silicon carbide-based lithium niobate film is effectively improved compared to the lithium niobate layer on silicon carbide obtained by magnetron sputtering, and the quality of the annealed silicon carbide-based lithium niobate film meets the application requirements. The characterization results of the silicon carbide-based lithium niobate film obtained in Example 2 are used as an example for illustration. Figure 2b This is the Raman spectrum of the silicon carbide-based lithium niobate film obtained in Example 2. Figure 2b The Raman characteristic peak 1TO (153 cm -1 ), 2TO(237cm -1), 3TO(264cm -1 ), 4TO(332cm -1 ), 5TO(369cm -1 ), 7TO(433cm -1 ), 8TO(583cm -1 ) are more obvious, among which the half-peak width of the 1TO peak is 45.56cm -1 It is a smaller value, indicating that the lithium element loss after lithium niobate annealing is less, and the obvious Raman characteristic peak and the small half-peak width of the 1TO peak indicate that the quality of lithium niobate film is good; Figure 3b is the XRD pattern of the silicon carbide-based lithium niobate film obtained in Example 2, Figure 3b The XRD characteristic peaks of lithium niobate crystals are very complex. The main characteristic peaks of lithium niobate are Figure 3b The peaks in the graph are all reflected, including (1 0 4) peak (23.7°), (1 1 0) peak (32.8°), (0 0 6) peak (34.9°), (1 1 3) peak (39.1°), (2 0 2) peak (40.2°), etc., and the half-peak widths of the characteristic peaks in the figure are all small, and there are no extra impurity peaks, indicating that the purity of lithium niobate in the film is high and the quality is good. Figure 2a , Figure 2b and Figure 2c as well as Figure 3a , Figure 3b and Figure 3c It can be seen that when the annealing temperature rises from 600℃ to 850℃, the recrystallization effect of lithium niobate is effectively improved and the film quality is improved; when the annealing temperature rises to 900℃, the recrystallization effect is almost constant, and the difference between 850℃ and 900℃ in improving the crystallization quality of the film is not obvious. Considering the saving of unnecessary energy consumption, 850℃ is a better annealing temperature. Figure 2b , Figure 2d and Figure 2e as well as Figure 3b , Figure 3d and Figure 3e It can be seen that with the increase of annealing time, the recrystallization effect of lithium niobate is effectively improved and the quality of the film is improved.
[0045] The method for preparing a silicon carbide-based lithium niobate film provided in this embodiment grows a lithium niobate layer on the surface of a silicon carbide substrate by a magnetron sputtering process, and improves its crystal quality by annealing, thereby realizing the preparation of a high-quality silicon carbide-based lithium niobate film by a magnetron sputtering process, effectively reducing the manufacturing cost of the silicon carbide-based lithium niobate film, and providing a method for preparing a high-quality silicon carbide-based lithium niobate film at a low cost. The process route of the magnetron sputtering combined with annealing provided in this embodiment is simple, and allows the stoichiometric ratio of lithium niobate to be controlled during the magnetron sputtering process, which can achieve a relatively low deposition temperature and reduce the difficulty of preparing the silicon carbide-based lithium niobate film.
[0046] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.
Claims
1. A method for preparing a silicon carbide-based lithium niobate film, characterized in that: The following steps are involved: S1: growing a lithium niobate layer on the surface of a silicon carbide substrate by magnetron sputtering; S2: Annealing is performed at a temperature of 600 to 900° C., and after cooling, a silicon carbide-based lithium niobate film is obtained.
2. The method for preparing a silicon carbide-based lithium niobate thin film according to claim 1, characterized in that: The magnetron sputtering process includes: a laser magnetron sputtering process, a high-power pulse magnetron sputtering process, an ion beam enhanced magnetron sputtering process or a radio frequency magnetron sputtering process.
3. The method for preparing a silicon carbide-based lithium niobate thin film according to claim 1, characterized in that: The magnetron sputtering process is a radio frequency magnetron sputtering process; the growth temperature of the radio frequency magnetron sputtering process is 500-700° C., the sputtering power is 50-60W, and the sputtering time is 120-240min.
4. The method for preparing a silicon carbide-based lithium niobate thin film according to claim 3, characterized in that: The sputtering atmosphere of the radio frequency magnetron sputtering process is argon or nitrogen.
5. The method for preparing a silicon carbide-based lithium niobate thin film according to claim 1, characterized in that: The annealing time is 30 to 120 minutes, the annealing atmosphere is argon, and the heating rate is 5 to 15° C. / min.
6. The method for preparing a silicon carbide-based lithium niobate thin film according to claim 1, characterized in that: The crystal plane of the silicon carbide substrate is a (0001) plane.
7. The method for preparing a silicon carbide-based lithium niobate thin film according to claim 1, characterized in that: The annealing device includes: a tubular annealing furnace, a box annealing furnace, a vacuum annealing furnace or an atmosphere annealing furnace.
8. The method for preparing a silicon carbide-based lithium niobate thin film according to claim 1, characterized in that: Before S1, it also included: The silicon carbide substrate is pretreated to remove contamination and damage on the surface of the silicon carbide substrate.
9. The method for preparing a silicon carbide-based lithium niobate thin film according to claim 8, characterized in that: The pretreatment includes: chemical mechanical polishing, cleaning and hydrogen etching performed in sequence.
10. The method for preparing a silicon carbide-based lithium niobate thin film according to claim 9, characterized in that: The temperature of the hydrogen etching is 1400-1600° C., and the time is 20-30 minutes.