A high-performance water-soluble sacrificial material and its preparation method and application

Abstract

The present invention provides a high-performance water-soluble sacrificial material and a preparation method and application thereof. The chemical formula of the water-soluble sacrificial material is A2B2Al2O7 or M4Al2O7; wherein A is one of Ca and Ba; B is Sr; and M is one of Ca, Sr, and Ba. The present invention is a water-soluble sacrificial material of the (Ca, Sr, Ba)4Al2O7 system, which has good universality in the preparation of self-supporting films; the water-soluble sacrificial layer of the present invention has high crystallinity and a smooth surface, providing an excellent platform for the high-quality growth of subsequent target films; the water-soluble sacrificial material of the present invention can be epitaxially grown with high quality on many substrates, thereby obtaining a self-supporting film with high crystallinity and high integrity.

Description

Technical Field

[0001] The invention relates to the technical field of water-soluble sacrificial materials, and in particular to a high-performance water-soluble sacrificial material and a preparation method and application thereof. Background Art

[0002] Oxide films have many fascinating properties, such as ferromagnetism, ferroelectricity and superconductivity, but their application and research on their intrinsic properties are sometimes constrained by the substrate. In the prior art, the oxide film is peeled off from the substrate by technical means, which can eliminate the influence of the interface and stress on the oxide film, and after being freed from the constraints of the substrate, the film can be further transferred, which greatly facilitates the application of oxide films.

[0003] In recent years, the technology of stripping oxide films using water-soluble sacrificial materials has developed rapidly. The main water-soluble sacrificial materials used are (Ca, Sr, Ba)3Al2O6 systems. Although the self-supporting films prepared using this material have good integrity and surface flatness, their crystallinity is far inferior to some traditional van der Waals materials such as graphene. The cracks formed on the self-supporting films due to stress release and human manipulation during the stripping process also seriously limit their further application. Researchers continue to optimize the growth conditions of the film and improve the film stripping and transfer techniques, but the results obtained are still far from satisfactory. In order to achieve the goal of obtaining high-quality self-supporting films, a suitable water-soluble sacrificial layer is extremely important for the growth of high-quality double-layer / multilayer films (sacrificial layer and target film). Summary of the invention

[0004] The technical problem to be solved by the present invention is how to improve the performance and adaptability of water-soluble sacrificial materials.

[0005] The present invention solves the above technical problems through the following technical means:

[0006] The first aspect of the present invention provides a high-performance water-soluble sacrificial material, the chemical formula of which is A2B2Al2O7 or M4Al2O7; wherein A is one of Ca and Ba; B is Sr; and M is one of Ca, Sr, and Ba.

[0007] Beneficial effects: The present invention is a water-soluble sacrificial material of the (Ca, Sr, Ba)4Al2O7 system, which has good universality in the preparation of self-supporting films; the water-soluble sacrificial layer of the present invention has high crystallinity and a smooth surface, providing an excellent platform for the high-quality growth of subsequent target films; the water-soluble sacrificial material of the present invention can be epitaxially grown with high quality on many substrates, thereby obtaining a self-supporting film with high crystallinity and high integrity.

[0008] Preferably, the lattice constant of the water-soluble sacrificial material is in the range of

[0009] Beneficial effect: The present invention controls the ratio of Ca, Sr and Ba in the water-soluble sacrificial material so that the lattice constant of the water-soluble sacrificial material is It is adjustable, and can reduce stress by adjusting the lattice constant of the water-soluble sacrificial material, thereby reducing wrinkles and cracks generated during the peeling and transfer of the self-supporting film. Therefore, it has good universality in the preparation of self-supporting films in the field of oxides.

[0010] The second aspect of the present invention provides a method for preparing the above-mentioned water-soluble sacrificial material. There are three preparation methods, namely, pulsed laser deposition, molecular beam epitaxy or magnetron sputtering to prepare high-performance water-soluble sacrificial materials.

[0011] Preferably, when pulsed laser deposition and magnetron sputtering are used, the raw materials for preparing Ca4Al2O7 are CaCO3 and Al2O3 in a molar ratio of 4:1; the raw materials for preparing Ca2Sr2Al2O7 are CaCO3, SrCO3, and Al2O3 in a molar ratio of 2:2:1; the raw materials for preparing Sr4Al2O7 are SrCO3 and Al2O3 in a molar ratio of 4:1; the raw materials for preparing Ba2Sr2Al2O7 are BaCO3, SrCO3, and Al2O3 in a molar ratio of 2:2:1.

[0012] Preferably, when the pulsed laser deposition method and the magnetron sputtering method are used, the raw materials are first batched, mixed, ground, pre-calcined, pressed into shape, and sintered according to a molar ratio to obtain a ceramic target.

[0013] Preferably, when the pulse laser deposition method and the magnetron sputtering method are used, the pre-calcination temperature is 900-1300° C., and the heat preservation time is 6-12 hours; the sintering temperature is 1300-1500° C., and the heat preservation time is 12-24 hours.

[0014] Preferably, when the pulse laser deposition method is adopted, a KrF gas laser is used to bombard the ceramic target material to deposit the water-soluble sacrificial material on the surface of the single crystal substrate.

[0015] Preferably, when pulse laser deposition is used, the temperature of the single crystal substrate is 600-800°C and the oxygen pressure is 10 -5 Pa~30Pa.

[0016] Preferably, the laser frequency is 1-8 Hz, and the laser energy density is 0.8-4.2 J / cm 2 .

[0017] Preferably, when the magnetron sputtering method is adopted, under the action of the electric field, high-energy particles bombard the surface of the ceramic target material, sputter out the coating particles and deposit the water-soluble sacrificial material on the surface of the single crystal substrate.

[0018] Preferably, when the magnetron sputtering method is adopted, the argon pressure in the chamber during the deposition is 1-10 Pa, and the sputtering power is 10-60 W.

[0019] Preferably, when the magnetron sputtering method is adopted, the prepared water-soluble sacrificial material is subjected to a post-annealing treatment, and the post-annealing temperature is 600-1000°C.

[0020] Preferably, when the molecular beam epitaxy method is adopted, the flux ratio of Ca and Al is controlled to be 2:1 when preparing Ca4Al2O7; the flux ratio of Ca, Sr and Al is controlled to be 1:1:1 when preparing Ca2Sr2Al2O7; the flux ratio of Sr and Al is controlled to be 2:1 when preparing Sr4Al2O7; the flux ratio of Ba, Sr and Al is controlled to be 1:1:1 when preparing Ba2Sr2Al2O7; the flux ratio of Ba and Al is controlled to be 2:1 when preparing Ba4Al2O7; and a water-soluble sacrificial material is grown on a single crystal substrate.

[0021] Preferably, when the molecular beam epitaxy method is used, the temperature of the single crystal substrate during the deposition process is 600-800°C, and the oxygen pressure is 10 -5 Pa~10Pa.

[0022] Preferably, the single crystal substrate is lanthanum aluminate (LaAlO3), neodymium gallate (NdGaO3), strontium titanate (SrTiO3), strontium tantalate aluminate [(LaAlO3) 0.3 -(SrAl 0.5 Ta 0.5 O3) 0.7 ], one of dysprosium scandate (DyScO3), potassium tantalate (KTaO3), lanthanum strontium aluminate (LaSrAlO4), and lanthanum strontium gallate (LaSrGaO4).

[0023] Beneficial effects: The high-performance water-soluble sacrificial material prepared by the present invention dissolves faster than the (Ca, Sr, Ba)3Al2O6 system, and the high-performance water-soluble sacrificial material prepared by the present invention is dissolved in deionized water. The dissolution process will not corrode and damage the target film and substrate, and will not introduce other impurities. Therefore, the self-supporting film used for preparation is more complete and clean, and the substrate after peeling can be used multiple times.

[0024] The water-soluble sacrificial material system prepared by the present invention adjusts the lattice constant of the material by controlling the Ca / Sr / Ba ratio, thereby being able to adapt to more single crystal substrates and target films.

[0025] The third aspect of the present invention provides the use of the above-mentioned high-performance water-soluble sacrificial material or the high-performance water-soluble sacrificial material prepared by the above-mentioned preparation method in the preparation of a self-supporting film material.

[0026] The advantages of the present invention are:

[0027] The present invention is a water-soluble sacrificial material of the (Ca, Sr, Ba)4Al2O7 system, which has good universality in preparing self-supporting films; the water-soluble sacrificial layer of the present invention has high crystallinity and a smooth surface, providing an excellent platform for the high-quality growth of subsequent target films; the water-soluble sacrificial material of the present invention can be epitaxially grown with high quality on many substrates, thereby obtaining a self-supporting film with high crystallinity and high integrity.

[0028] The present invention controls the ratio of Ca, Sr and Ba in the water-soluble sacrificial material so that the lattice constant of the water-soluble sacrificial material is within It is adjustable, and can reduce stress by adjusting the lattice constant of the water-soluble sacrificial material, thereby reducing wrinkles and cracks generated during the peeling and transfer of the self-supporting film. Therefore, it has good universality in the preparation of self-supporting films in the field of oxides.

[0029] The high-performance water-soluble sacrificial material prepared by the present invention has a faster water dissolution rate than the (Ca, Sr, Ba)3Al2O6 system, and the high-performance water-soluble sacrificial material prepared by the present invention is dissolved in deionized water. The dissolution process will not corrode and damage the target film and substrate, and will not introduce other impurities. Therefore, the self-supporting film used for preparation is more complete and clean, and the substrate after peeling can be used multiple times.

[0030] The water-soluble sacrificial material system prepared by the present invention adjusts the lattice constant of the material by controlling the Ca / Sr / Ba ratio, thereby being able to adapt to more single crystal substrates and target films. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The X-ray diffraction 2θ-ω diagram and reciprocal space diagram of the Sr4Al2O7 (SAO) film grown on the LSAT (001) substrate in Example 1;

[0032] Figure 2 X-ray diffraction 2θ-ω diagrams and reciprocal space diagrams of the Ca2Sr2Al2O7 (CSAO) film and the NdNiO3 (NNO) film grown on the LAO (001) substrate in Example 2;

[0033] Figure 3 These are the X-ray diffraction 2θ-ω diagram and reciprocal space diagram of the Ba2Sr2Al2O7 (BSAO) film grown on the KTO (001) substrate in Example 3. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0036] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0037] Example 1

[0038] This embodiment provides a Sr4Al2O7 water-soluble sacrificial material and a preparation method thereof. The preparation method is a pulsed laser deposition method, and the specific steps are as follows:

[0039] (1) According to the molecular formula of the water-soluble sacrificial material Sr4Al2O7, the raw materials are SrCO3 and Al2O3; the molar ratio is 4:1, and then the materials are mixed and ground, and pre-calcined at 1000-1300°C for 3 times, each time for 12 hours, and then pressed into shape, and finally sintered at 1400°C for 24 hours to obtain the Sr4Al2O7 ceramic target.

[0040] (2) KrF gas laser was used to bombard Sr4Al2O7 ceramic target, and Sr4Al2O7 single crystal water-soluble sacrificial material was deposited on the surface of strontium tantalum lanthanum aluminate (001) oriented [LSAT (001)] single crystal substrate. During the deposition process, the surface temperature of the single crystal substrate was maintained at 650°C, and the oxygen pressure of the deposition environment was maintained at 1Pa; the energy density of the pulsed laser was 2.5J / cm 2 , spot size is 2mm 2 ; The frequency of the pulse laser is 5 Hz and the deposition time is 8 min.

[0041] In this embodiment, the prepared Sr4Al2O7 single crystal water-soluble sacrificial material is an orthorhombic phase with a thickness of 60 nm. Figure 1 The X-ray diffraction 2θ-ω linear scan results and reciprocal space map (RSM) of the water-soluble sacrificial material prepared in this embodiment. The clear Laue oscillation indicates the high-quality growth of the water-soluble sacrificial material, and the thickness of the water-soluble sacrificial material can be calculated to be about 60nm. From the RSM, it can be seen that the Sr4Al2O7 water-soluble sacrificial material is in an epitaxial relationship with the LSAT (001) substrate and is subjected to the biaxial strain of the substrate.

[0042] Example 2

[0043] This embodiment provides a Ca2Sr2Al2O7 water-soluble sacrificial material and a preparation method thereof. The preparation method is a molecular beam epitaxy technology, and the specific steps are as follows:

[0044] (1) In this embodiment, the flux ratio of Ca, Sr, and Al is controlled to be 1:1:1 by controlling the temperature of the molecular beam source, and Ca2Sr2Al2O7 water-soluble sacrificial material is epitaxially grown on the surface of LaAlO3(001) [LAO(001)] single crystal substrate. The Ca2Sr2Al2O7 water-soluble sacrificial material is deposited to a thickness of 30 nm and then annealed in situ for 5 min.

[0045] (2) After in-situ annealing, a NdNiO3 thin film with a thickness of 30 nm is epitaxially grown on the Ca2Sr2Al2O7 water-soluble sacrificial material.

[0046] Figure 2 The X-ray diffraction 2θ-ω linear scan results and reciprocal space map (RSM) of the water-soluble sacrificial material prepared in this example. In the 2θ-ω linear scan results, there are clear Laue oscillations near the two film peaks, indicating the high-quality growth of the Ca2Sr2Al2O7 water-soluble sacrificial material and the NdNiO3 film. From the RSM, it can be seen that the NdNiO3 film and the Ca2Sr2Al2O7 water-soluble sacrificial material are co-grown on the LAO (001) substrate; the in-plane lattice constant of the Ca2Sr2Al2O7 water-soluble sacrificial material is

[0047] Example 3

[0048] This embodiment provides a Ba2Sr2Al2O7 water-soluble sacrificial material and a preparation method thereof. The preparation method is a magnetron sputtering method, and the specific steps are as follows:

[0049] (1) According to the molecular formula of the water-soluble sacrificial material Ba2Sr2Al2O7, the raw materials are BaCO3, SrCO3 and Al2O3; the molar ratio is 1:1:1, and then the materials are mixed and ground, and pre-calcined at 1000-1300°C for 3 times, each time for 12 hours, and then pressed into shape, and finally sintered at 1400°C for 24 hours to obtain the Ba2Sr2Al2O7 ceramic target.

[0050] (2) Using a Ba2Sr2Al2O7 ceramic target, the argon pressure in the chamber was adjusted to 1 Pa, the sputtering power was adjusted to 30 W, the baffle was opened, and Ba2Sr2Al2O7 water-soluble sacrificial material was deposited on a KTaO3(001) [KTO(001)] substrate.

[0051] (3) The prepared water-soluble sacrificial material is placed in a muffle furnace and annealed at 700° C. for 5 hours to improve the crystallinity of the water-soluble sacrificial material.

[0052] Figure 3 The X-ray diffraction 2θ-ω linear scan results and reciprocal space map (RSM) of the water-soluble sacrificial material prepared in this embodiment. From the 2θ-ω linear scan results, it can be seen that the Ba2Sr2Al2O7 water-soluble sacrificial material has good single crystallinity. From the RSM, it can be seen that the Ba2Sr2Al2O7 film and the KTO (001) substrate are in an epitaxial relationship, and the in-plane lattice constant of the Ba2Sr2Al2O7 water-soluble sacrificial material is

[0053] The present invention is a water-soluble sacrificial material of the (Ca, Sr, Ba)4Al2O7 system, which has good universality in preparing self-supporting films; the water-soluble sacrificial layer of the present invention has high crystallinity and a smooth surface, providing an excellent platform for the high-quality growth of subsequent target films; the water-soluble sacrificial material of the present invention can be epitaxially grown with high quality on many substrates, thereby obtaining a self-supporting film with high crystallinity and high integrity.

[0054] The present invention controls the ratio of Ca, Sr and Ba in the water-soluble sacrificial material so that the lattice constant of the water-soluble sacrificial material is within It is adjustable, and can reduce stress by adjusting the lattice constant of the water-soluble sacrificial material, thereby reducing wrinkles and cracks generated during the peeling and transfer of the self-supporting film. Therefore, it has good universality in the preparation of self-supporting films in the field of oxides.

[0055] The high-performance water-soluble sacrificial material prepared by the present invention has a faster water dissolution rate than the (Ca, Sr, Ba)3Al2O6 system, and the high-performance water-soluble sacrificial material prepared by the present invention is dissolved in deionized water. The dissolution process will not corrode and damage the target film and substrate, and will not introduce other impurities. Therefore, the self-supporting film used for preparation is more complete and clean, and the substrate after peeling can be used multiple times.

[0056] The water-soluble sacrificial material system prepared by the present invention adjusts the lattice constant of the material by controlling the Ca / Sr / Ba ratio, thereby being able to adapt to more single crystal substrates and target films.

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-performance water-soluble sacrificial material, characterized in that: The chemical formula of the water-soluble sacrificial material is A2B2Al2O7 or M4Al2O7, wherein A is one of Ca and Ba; B is Sr; and M is one of Ca and Ba.

2. The high performance water-soluble sacrificial material according to claim 1, characterized in that: The lattice constant of the water-soluble sacrificial material is in the range of 3. The method for preparing a high-performance water-soluble sacrificial material according to claim 1 or 2, characterized in that: The high-performance water-soluble sacrificial material is prepared by pulse laser deposition, molecular beam epitaxy or magnetron sputtering.

4. The preparation method according to claim 3, characterized in that: When pulse laser deposition or magnetron sputtering is used, the raw materials for preparing Ca4Al2O7 are CaCO3 and Al2O3, and the molar ratio is 4:1; the raw materials for preparing Ca2Sr2Al2O7 are CaCO3, SrCO3, and Al2O3, and the molar ratio is 2:2:1; the raw materials for preparing Ba2Sr2Al2O are BaCO3, SrCO3, and Al2O3, and the molar ratio is 2:2:

1.

5. The preparation method according to claim 4, characterized in that: When the pulse laser deposition method or the magnetron sputtering method is used, the raw materials are firstly batched, mixed, ground, pre-calcined, pressed into shape, and sintered according to a molar ratio to obtain a ceramic target.

6. The preparation method according to claim 5, characterized in that: When using pulsed laser deposition, a KrF gas laser is used to bombard a ceramic target to deposit a water-soluble sacrificial material on the surface of a single crystal substrate.

7. The preparation method according to claim 5, characterized in that: When the magnetron sputtering method is used, high-energy particles bombard the surface of the ceramic target under the action of an electric field, sputtering out coating particles and depositing on the surface of the single crystal substrate to form a water-soluble sacrificial material.

8. The preparation method according to claim 3, characterized in that: When the molecular beam epitaxy method is used, the flux ratio of Ca and Al is controlled to be 2:1 when preparing Ca4Al2O7; the flux ratio of Ca, Sr and Al is controlled to be 1:1:1 when preparing Ca2Sr2Al2O7; the flux ratio of Ba, Sr and Al is controlled to be 1:1:1 when preparing Ba2Sr2Al2O7; the flux ratio of Ba and Al is controlled to be 2:1 when preparing Ba4Al2O7; and a water-soluble sacrificial material is grown in a single crystal substrate.

9. The preparation method according to any one of claims 6 to 8, characterized in that: The single crystal substrate is one of lanthanum aluminate, neodymium gallate, strontium titanate, strontium tantalate lanthanum aluminate, dysprosium scandate, potassium tantalate, strontium lanthanum aluminate, and strontium lanthanum gallate.

10. Use of the high-performance water-soluble sacrificial material according to claim 1 or 2 or the high-performance water-soluble sacrificial material obtained by the preparation method according to any one of claims 3 to 9 in the preparation of a self-supporting film material.

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