Method for processing probe direct-writing atomic layer on surface of FCC (Fluid Catalytic Cracking) crystal material

Abstract

The invention relates to a method for processing a probe direct-writing atomic layer on the surface of an FCC (fluid catalytic cracking) crystal material, and relates to the technical field of ultra-precision manufacturing, the processing method comprises the following steps: selecting a scanning probe as a processing tool; and carrying out scribing processing from the position of the FCC crystal material with the dangling bond to the direction without the dangling bond according to a preset processing track. According to the probe direct-writing atomic layer processing method provided by the invention, the processing application range of the scanning probe can be widened to a blocky FCC crystal material, and the limitation that only a silicon dioxide tip can be utilized to remove a two-dimensional material in a traditional scanning probe processing method is solved; atomic-scale precision manufacturing of the ionic crystal material of the face-centered cubic structure can be achieved, and the application range of the scanning probe machining method is widened. Meanwhile, the application material range of the scanning probe can be widened, and besides active materials such as silicon and silicon oxide, inert materials can also be adopted, so that the selection range of machining tool materials is widened.

Description

Technical Field

[0001] The present invention relates to the field of ultra-precision manufacturing technology, and specifically to a probe direct writing atomic layer processing method for the surface of FCC crystal materials. Background Art

[0002] Atomic-level manufacturing refers to a cutting-edge manufacturing technology that acts on atoms with energy and advances the controllable amount of manufacturing to the atomic and atomic elemental levels to achieve a leap in product performance and function. Currently, the main method for realizing atomic layer removal is Atomic Layer Etching (ALE). This method uses an etching gas to undergo a self-limiting reaction with the target material to generate reactive substances, and then uses low-energy argon ions to directionally remove the reaction products, thereby exposing a new layer of the target material. The ion energy needs to be precisely controlled so that it only removes the reaction layer without attacking the underlying unchemically adsorbed substrate material. By continuously repeating this cycle, the purpose of atomic-level etching is ultimately achieved. However, this method mainly uses specific chemical reactions to achieve atomic-level removal of materials, and it is difficult to ensure that chemically inert materials can also undergo the above self-limiting reaction. Therefore, the applicability of this method is not strong.

[0003] Another method is scanning probe processing, which uses mechanical action or tribochemical reactions to achieve micro-nano scale removal of materials. However, currently, it is only recorded that the surface of two-dimensional materials such as graphene can use this method to achieve ultimate processing of a single atomic layer or atomic-level precision surface, and currently, the scanning probe usually requires strong surface chemical activity, which limits the application range of this solution. Summary of the Invention

[0004] The purpose of the present invention is to provide a probe direct writing atomic layer processing method for the surface of FCC crystal materials, aiming to explore a wider application range of scanning probe processing.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A probe direct writing atomic layer processing method for the surface of FCC crystal materials, comprising the following steps:

[0006] Select a scanning probe as the processing tool;

[0007] Scratch and process from the position with dangling bonds on the FCC crystal material in the direction without dangling bonds according to a preset processing trajectory.

[0008] In a preferred embodiment, the material of the scanning probe is one of diamond, alumina, silica, silicon, cerium oxide, and silicon nitride.

[0009] In a preferred embodiment, the shape of the scanning probe is one of spherical, conical, square, rhombic, and triangular.

[0010] In a preferred embodiment, the scanning probe is mounted on a scanning probe processing device.

[0011] In a preferred embodiment, the scanning probe processing device is used to characterize the surface topography of the FCC crystal material and locate the positions of dangling bonds according to the surface topography.

[0012] In a preferred embodiment, the accuracy of the scanning probe processing device is above sub-nanometer displacement accuracy.

[0013] In a preferred embodiment, the preset processing trajectory is parallel to the (001) crystal plane or the (010) crystal plane or the (100) crystal plane.

[0014] In a preferred embodiment, the air humidity of the processing environment is set above 20%.

[0015] In a preferred embodiment, the positions of the dangling bonds include material defect positions and step edge positions.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. The probe direct writing atomic layer processing method provided by the present invention can broaden the application scope of scanning probe processing to bulk FCC crystal materials, solve the limitation that the traditional scanning probe processing method can only use silicon dioxide tips to achieve two-dimensional material removal, and based on the stress corrosion effect, can achieve atomic-level precision manufacturing of ionic crystal materials with a face-centered cubic (FCC) structure (such as CaF2, NaCl, MgO, etc.), thus broadening the application scope of the scanning probe processing method.

[0018] 2. The present invention takes the positions of the dangling bonds in the FCC crystal material as the starting positions of the etching process, and makes full use of the interaction between the probe and the unstable and highly chemically active dangling bonds, and can achieve atomic-level precision removal of the surface of the ionic crystal material with an FCC structure;

[0019] At the same time, the etching process is carried out according to the processing trajectory parallel to the (001) crystal plane or the (010) crystal plane or the (100) crystal plane of the FCC crystal material. By using the characteristics of these three planes, which are mainly van der Waals forces, lack strong ionic bonds or covalent bonds, and the highly symmetric crystal structure can limit its polarization effect, resulting in a lower surface energy and obvious electron localization, the stress corrosion effect is most likely to remove in these three plane directions.

[0020] 3. By adopting the above special etching process for the FCC crystal material, the present invention can simultaneously broaden the application material range of the scanning probe. In addition to active materials such as silicon and silicon dioxide, inert materials such as diamond can also be used, increasing the selection range of processing tool materials. Brief Description of the Drawings

[0021] Figure 1 Schematic diagram of the single crystal CaF2 atomic lattice in Embodiment 1 of the present invention;

[0022] Figure 2 Surface morphology of the CaF2 crystal material after etching in Embodiment 1 of the present invention;

[0023] Figure 3 is Figure 2 Cross-sectional curve of the white solid line area in;

[0024] Figure 4 is Figure 2 Lattice image of the surface scan after removing the atomic layer in the white wireframe area in;

[0025] Figure 5 Surface morphology of the BaF2 crystal material after etching in Embodiment 2 of the present invention;

[0026] Figure 6 Surface morphology of the MgO crystal material after etching in Embodiment 3 of the present invention;

[0027] Figure 7 Surface morphology of the CaF2 crystal material after etching in Embodiment 4 of the present invention;

[0028] Figure 8 Surface morphology of the CaF2 crystal material after etching in Comparative Example 1 of the present invention;

[0029] Figure 9 is Figure 8 Cross-sectional curve of the white solid line area in;

[0030] Figure 10 Surface morphology of the CaF2 crystal material after etching in Comparative Example 2 of the present invention;

[0031] Figure 11 Surface morphology of the SiC crystal material after etching in Comparative Example 3 of the present invention;

[0032] Figure 12 is Figure 11 Cross-sectional curve of the white solid line area in. Detailed Description of the Invention

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention.

[0035] The present invention discloses a method for probe direct writing atomic layer processing on the surface of an FCC (face-centered cubic structure) crystal material, comprising the following steps:

[0036] Select a scanning probe as the processing tool;

[0037] According to the scanned surface topography of the material, starting from the position where the FCC crystal material has dangling bonds, scribing and processing are carried out in the direction without dangling bonds according to a preset processing trajectory to remove the surface layer atoms of the material.

[0038] Specifically, in the present invention, the material of the scanning probe can be an active material or an inert material. Exemplarily, the material of the scanning probe is one of diamond, alumina, silica, silicon, cerium oxide, and silicon nitride.

[0039] The shape of the scanning probe is one of spherical, conical, square, rhombic, and triangular.

[0040] In practical applications, the scanning probe needs to be installed on a scanning probe processing device, which is used to characterize the surface topography of the FCC crystal material and locate the position of the dangling bonds of the FCC crystal material according to this surface topography. The accuracy of the scanning probe processing device is above the sub-nanometer displacement accuracy to achieve precise control of the mechanical stress applied to the crystal material. By precisely controlling the applied mechanical stress, material spalling and delamination at the atomic level on the surface of the ionic crystal can be achieved.

[0041] It should be noted that when mechanical force acts on the area of the material surface without dangling bonds, a force that causes the material surface to yield needs to be applied to achieve the material removal behavior. At this time, the amount of material removed is uncontrollable, generally in the nanometer or micrometer range. In addition, it will also cause defects such as cracks, dislocations, and lattice damage on the material surface and subsurface. Therefore, in the present invention, starting from the position of the FCC crystal material with dangling bonds, scribing processing is carried out in the direction without dangling bonds according to a preset processing trajectory to remove the surface layer atoms of the material. The present invention starts from the inherent defects or step edges of the material surface with dangling bonds, and by precisely applying mechanical stress to it, using the interaction (mechanical or tribochemical action) between the probe and the unstable and highly chemically active dangling bonds, atomic-level precision removal of the surface of the ionic crystal material with an FCC structure can be achieved. In addition, since the applied stress acts on the plane as pure elastic deformation, it will not cause damage to the lower plane, thus ensuring the integrity of the lower surface structure. Compared with the pure mechanical removal directly acting on the plane, the mechanical stress removed by the method provided by the present invention is extremely low, and can significantly reduce by 1-2 orders of magnitude. This method can overcome the problem that the amount of material removed is difficult to accurately control in the traditional method, and also ensures the integrity and high precision of the surface crystal structure after processing.

[0042] In the present invention, the positions of the dangling bonds include but are not limited to the material defect positions and the step edge positions.

[0043] Furthermore, in the present invention, scribing processing is carried out from the position of the FCC crystal material with dangling bonds in the direction without dangling bonds according to a preset processing trajectory, and the preset processing trajectory is parallel to the (001) crystal plane or (010) crystal plane or (100) crystal plane of the FCC crystal material. In the FCC crystal material, the (001) crystal plane, (010) crystal plane, and (100) crystal plane are mainly van der Waals forces, lacking strong ionic bonds or covalent bonds. The highly symmetric crystal structure limits the polarization effect, making its surface energy relatively low and the electron localization obvious, which makes the stress corrosion effect most likely to remove in the direction of these three planes.

[0044] In the present invention, the air humidity of the processing environment needs to be set above 20%. Specifically, the electrostatic shielding effect of water molecules can weaken the electrostatic interaction between ions on the material surface and promote the dissolution of the ionic crystal surface; at the same time, during the sliding of the tip of the scanning probe, the mechanical stress effect can further reduce the energy barrier for ionic bond breaking and accelerate the release and dissolution of surface ions.

[0045] The following further elaborates on the present invention in combination with embodiments. Similarly, it should be understood that the following embodiments are only used to further illustrate the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the protection scope of the present invention.

[0046] Example 1

[0047] In this example, the FCC crystal material is CaF2;

[0048] The scanning probe is made of silicon nitride material, the radius of curvature of the tip is 15 nm, and the elastic coefficient is 0.7 N / m;

[0049] Atomic-level removal conditions on the material surface:

[0050] Load: 150 nN (contact pressure: 5.4 GPa), scratching speed: 2 μm / s, number of scratching times: 1 time.

[0051] Scratching range: 500 * 500 nm 2 , Removal depth: 0.32 nm (F-Ca-F atomic layer), and the surface is not damaged.

[0052] Removal starting area: Defect area.

[0053] In this example, the probe direct writing atomic layer processing method on the surface of the FCC (face-centered cubic structure) crystal material includes the following steps:

[0054] Select the above-mentioned scanning probe made of silicon nitride material as the processing tool;

[0055] According to the surface topography of the CaF2 material scanned, starting from the defect area of the material, the tip slides along the direction parallel to the (001) crystal plane for scratching processing to remove the surface layer atoms of the material.

[0056] Basic principle of atomic-level removal on the material surface: There are a large number of highly chemically active CaF2 single-layer or several-layer atomic edges at the surface defects of single-crystal calcium fluoride. In CaF2, the electronegativity of Ca is about 1.0, while the electronegativity of fluorine F is about 4.0, and the difference in their electronegativities is very large (Δχ≈3.0). This difference far exceeds the typical range for forming covalent bonds (usually Δχ<1.7 is more inclined to covalent bonds). Therefore, the connection between Ca and F is mainly ionic bonds. When mechanical stress is applied to the edge of this single-layer or several-layer atoms, an interfacial bridge bond can be formed between the outermost layer atoms of the tip-CaF2. Under the action of the bridge bond, atomic-level removal can be achieved by applying mechanical stress lower than the plane destruction.

[0057] Figure 1 is a schematic diagram of the atomic lattice of single-crystal CaF2, Figure 2 shows the surface topography of the CaF2 crystal material after scratching in this example. The scratched area is within the black dotted line frame; Figure 3 is Figure 2 the cross-sectional curve of the white solid line area in, and it can be seen from this figure that only the F-Ca-F single-layer atoms are removed in the scratched area; Figure 4 isFigure 2 The lattice image of the surface after atomic layer removal in the white wireframe area. It can be seen from this image that the lattice resolution is well - shown, indicating that the surface lattice is complete after removal and there is almost no subsurface lattice damage.

[0058] Example 2

[0059] In this example, the FCC crystal material is BaF2;

[0060] The scanning probe is made of alumina material, the curvature radius of the tip is 1250 nm, and the elastic coefficient is 16 N / m;

[0061] The atomic - level removal conditions on the material surface:

[0062] Load: 2 μN (contact pressure: 0.59 GPa), scratching speed: 1 μm / s, number of scratching times: 10 times.

[0063] Scratching range: 500 * 500 nm 2 , Removal depth: 0.4 nm, and the surface is undamaged.

[0064] Removal starting area: step edge.

[0065] In this example, the probe - direct - writing atomic layer processing method on the surface of the FCC (face - centered cubic structure) crystal material includes the following steps:

[0066] Select the above - mentioned alumina scanning probe as the processing tool;

[0067] According to the scanned surface topography of the BaF2 material, starting from the step - edge area of the material, the tip slides along the direction parallel to the (010) crystal plane for scratching processing to remove the surface - layer atoms of the material.

[0068] The basic principle of atomic - level removal on the material surface in this example is similar to that in Example 1, and it will not be elaborated here.

[0069] Figure 5 The surface topography of the BaF2 crystal material after scratching in this example is shown. It can be seen from this attached figure that the surface topography of the scratched crystal material is flat.

[0070] Example 3

[0071] In this example, the FCC crystal material is MgO;

[0072] The scanning probe is made of silicon oxide material, the curvature radius of the tip is 1250 nm, and the elastic coefficient is 16 N / m;

[0073] The atomic - level removal conditions on the material surface:

[0074] Load: 1.2 μN (contact pressure: 0.56 GPa), scratching speed: 500 nm / s, number of scratching times: 1 time.

[0075] Scratching range: 500 * 500 nm 2 , removal depth: 0.5 nm, no surface damage.

[0076] Removal starting area: step edge.

[0077] In this embodiment, the probe direct writing atomic layer processing method on the surface of the FCC (face-centered cubic structure) crystal material includes the following steps:

[0078] Select the above-mentioned silicon oxide scanning probe as the processing tool;

[0079] According to the surface topography of the scanned MgO material, starting from the step edge area of the material, the tip slides along the direction parallel to the (100) crystal plane for scratching processing to remove the surface layer atoms of the material.

[0080] The basic principle of atomic-level removal of the material surface in this embodiment is similar to that of Embodiment 1, and will not be elaborated here.

[0081] Figure 6 The surface topography of the MgO crystal material after scratching in this embodiment is shown. It can be seen from this figure that the surface topography of the scratched crystal material is flat.

[0082] Embodiment 4

[0083] In this embodiment, CaF2 is used for the FCC crystal material;

[0084] The scanning probe uses diamond material, the curvature radius of the tip is 20 nm, and the elastic coefficient is 100 N / m;

[0085] Atomic-level removal conditions of the material surface:

[0086] Load: 0.5 μN (contact stress: 6.3 GPa), scratching speed: 2 μm / s, number of scratching times: 1 time.

[0087] Scratching range: 500 * 500 nm 2 , removal depth: 0.20 nm.

[0088] Removal starting area: defect area.

[0089] In this embodiment, the probe direct writing atomic layer processing method on the surface of the FCC (face-centered cubic structure) crystal material includes the following steps:

[0090] Select the scanning probe made of the above-mentioned diamond material as the processing tool;

[0091] According to the surface morphology of the CaF2 material scanned, starting from the defect area of the material, the tip slides along the direction parallel to the (001) crystal plane for scribing processing to remove the surface layer atoms of the material.

[0092] The basic principle of atomic-level removal of the material surface in this embodiment is similar to that in Embodiment 1, and will not be elaborated here.

[0093] Figure 7 The surface morphology of the CaF2 crystal material after scribing in this embodiment is shown. It can be seen from this figure that the surface morphology of the scribed crystal material is flat.

[0094] Comparative Example 1

[0095] The difference between this comparative example and Embodiment 1 is that the starting area for removal is: a non-defect area and not other positions with dangling bonds.

[0096] Specifically:

[0097] In this comparative example, the FCC crystal material is CaF2;

[0098] The scanning probe is made of silicon nitride material, the curvature radius of the tip is 15 nm, and the elastic coefficient is 0.7 N / m;

[0099] Atomic-level removal conditions of the material surface:

[0100] Load: 150 nN (contact pressure: 5.4 GPa), scribing speed: 2 μm / s, scribing times: 1 time.

[0101] Scribing range: 500 * 500 nm 2 , removal depth: 0 nm.

[0102] Starting area for removal: non-defect area, and the tip slides along the direction parallel to the (001) crystal plane for scribing processing.

[0103] Figure 8 The surface morphology of the CaF2 crystal material after scribing in this comparative example is shown. The scribed area is within the black dashed box; Figure 9 is Figure 8 the cross-sectional curve of the white solid area in, and it can be seen from this figure that no removal occurs in the scribed area.

[0104] It can be seen from the comparison between Comparative Example 1 and Embodiment 1 that setting the starting area for scribing to non-defect areas and other positions without dangling bonds of the FCC crystal material will make it difficult to produce a scribing effect.

[0105] Comparative Example 2

[0106] The difference between this comparative example and Example 1 is that, according to the surface topography of the CaF2 material scanned, starting from the defect area of the material, the tip slides along the (110) direction (not the 001, 010, 100 crystal planes) for scribing to remove the surface layer atoms of the material.

[0107] Specifically:

[0108] In this comparative example, the FCC crystal material is CaF2;

[0109] The scanning probe is made of silicon nitride material, the curvature radius of the tip is 15 nm, and the elastic coefficient is 0.7 N / m;

[0110] Atomic-level removal conditions of the material surface:

[0111] Load: 150 nN (contact pressure: 5.4 GPa), scribing speed: 2 μm / s, scribing times: 1 time.

[0112] Scribing range: 500*500 nm 2 , Removal depth: 0 nm.

[0113] Removal starting area: Defect area, the tip slides along the (110) direction for scribing.

[0114] Figure 10 This is the surface topography of the CaF2 crystal material after scribing in this comparative example. It can be seen from the comparison between Comparative Example 2 and Example 1 that if the tip of the scanning probe cannot scribe along the three plane directions of the (001) crystal plane, (010) crystal plane, and (100) crystal plane, due to the existence of strong ionic bonds or covalent bonds in other plane directions of the FCC crystal material, it is difficult to produce a good scribing effect even if the defect area is used as the starting area for removal.

[0115] Comparative Example 3

[0116] The difference between this comparative example and Example 1 is that this comparative example uses a non-FCC crystal material.

[0117] Specifically:

[0118] In this comparative example, the crystal material is bulk SiC;

[0119] The scanning probe is made of silicon nitride material, the curvature radius of the tip is 15 nm, and the elastic coefficient is 0.7 N / m;

[0120] Atomic-level removal conditions of the material surface:

[0121] Load: 150 nN (contact pressure: 5.4 GPa), scribing speed: 2 μm / s, scribing times: 1 time.

[0122] Scratching range: 500 * 500 nm 2 Removal depth: 0 nm.

[0123] Removal starting area: defect area, the tip slides along the direction parallel to the (001) crystal plane for scratching.

[0124] Figure 11 The surface morphology of the SiC crystal material after scratching in this comparative example is shown. The scratched area is within the black dashed box; Figure 12 is Figure 11 the cross-sectional curve of the white solid area in. It can be seen from this figure that no removal occurs in the scratched area.

[0125] It can be seen from the comparison between Comparative Example 3 and Example 1 that if the crystal material is a non-FCC material, it is difficult to produce a scratching effect.

[0126] Combining each example and comparative example, it can be seen that in Examples 1 to 4, by using an FCC crystal material, and taking the position with dangling bonds in the FCC crystal material as the starting position of the scratching process, and scratching along the processing trajectory parallel to the (001) crystal plane or (010) crystal plane or (100) crystal plane of the FCC crystal material towards the direction without dangling bonds, good scratching effects can be achieved.

[0127] In Comparative Example 1, the starting area of the scratching is set at a position without dangling bonds such as the non-defect area of the FCC crystal material, and in Comparative Example 3, a non-FCC bulk material is used. Both are difficult to produce a scratching effect. In Comparative Example 2, the tip of the scanning probe slides along a direction other than the (001) crystal plane, (010) crystal plane, and (100) crystal plane of the FCC crystal material, and its scratching effect is also difficult to meet the expectation.

[0128] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A probe direct writing atomic layer processing method on the surface of an FCC crystal material, characterized in that It includes the following steps: Select a scanning probe as the processing tool; From the position with dangling bonds in the FCC crystal material, perform scribing processing in the direction without dangling bonds according to a preset processing trajectory.

2. The probe direct writing atomic layer processing method on the surface of the FCC crystal material according to claim 1, characterized in that The material of the scanning probe is one of diamond, alumina, silica, silicon, cerium oxide, and silicon nitride.

3. The probe direct writing atomic layer processing method on the surface of the FCC crystal material according to claim 1, characterized in that, The shape of the scanning probe is one of spherical, conical, square, rhombic, and triangular.

4. The probe direct writing atomic layer processing method on the surface of the FCC crystal material according to claim 1, wherein Mount the scanning probe on a scanning probe processing device.

5. The probe direct writing atomic layer processing method on the surface of the FCC crystal material according to claim 4, characterized in that, The scanning probe processing device is used to characterize the surface morphology of the FCC crystal material and locate the position of dangling bonds according to the surface morphology.

6. The probe direct writing atomic layer processing method on the surface of the FCC crystal material according to claim 4, characterized in that, The accuracy of the scanning probe processing device is above sub-nanometer displacement accuracy.

7. The probe direct writing atomic layer processing method on the surface of the FCC crystal material according to claim 1, characterized in that, The preset processing trajectory is parallel to the (001) crystal plane or the (010) crystal plane or the (100) crystal plane.

8. The probe direct writing atomic layer processing method on the surface of the FCC crystal material according to claim 1, wherein The air humidity in the processing environment is set above 20%.

9. The probe direct writing atomic layer processing method on the surface of the FCC crystal material according to claim 1, characterized in that, The positions of the dangling bonds include material defect positions and step edge positions.

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