Method for improving elastic limit of micro-nano-scale diamond

Abstract

The invention belongs to the field of semiconductor materials and micro-nano manufacturing, and provides a method for improving the elastic limit of micro-nano-scale diamond. According to a diamond micro-nano structure prepared through a traditional method, due to surface defects and an amorphous layer, the mechanical property is far lower than a theoretical value, and the elastic strain and the fracture resistance are limited. According to the method, controllable plasma surface treatment is carried out on the diamond nanostructure processed by a focused ion beam (FIB) at room temperature, the thickness of a surface amorphous carbon layer is accurately regulated and controlled, and the elastic modulus and the elastic strain range are actively regulated. The core of the method is to reduce or optimize interface mismatch of a surface amorphous layer and internal crystalline diamond and relieve the problem of deformation and non-collaboration. After treatment, the ductility of the diamond is improved, the theoretical ultimate tensile strain is approached, the fracture resistance is enhanced, and the multi-field mechanical reliability and working stability are improved. The method is simple in process, mild in condition and high in controllability, and provides support for application of diamond-based micro-nano devices.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor materials, and relates to a method for improving the elastic limit of micro-nano-scale diamond. BACKGROUND

[0002] At present, with the rapid development of micro-nano electronics and quantum technology, the demand for high-performance semiconductor materials is increasingly urgent. Diamond is known as the "ultimate semiconductor material" due to its excellent thermal conductivity, high hardness and high carrier mobility, and has irreplaceable application value in the frontiers of micro-nano scale high-power electronic devices, high-frequency chips, integrated circuits and quantum technology. However, the wide and severe application scenarios put forward higher requirements for diamond semiconductors. In addition to excellent electrical properties, they also need to have excellent mechanical properties such as mechanical stability, fatigue resistance and wear resistance, so as to ensure stable operation under extreme conditions such as high frequency and high power, and have a long service life. In order to meet these needs, researchers are constantly exploring. Elastic strain engineering, as an effective method to adjust the band gap of semiconductor materials, has entered the field of view. Current research has found that reducing the size of diamond to the micro-nano scale can reduce the number of internal defects and improve its tolerable elastic strain.

[0003] However, how to controllably adjust the elastic properties of micro-nano scale diamond and improve the elastic limit to close to the theoretical value has become a key problem to be solved. In the aspect of material processing and modification, focused ion beam (FIB) is a commonly used micro-nano scale fine processing method. However, for diamond with strong covalent bonds, ion bombardment during FIB processing will inevitably produce an amorphous carbon layer on the surface. This amorphous carbon layer has a significant impact on the elastic deformation behavior of micro-nano scale diamond, interfering with the study of the intrinsic mechanical properties of diamond, and also seriously affecting the intrinsic mechanical properties of diamond.

[0004] To solve this problem, some research has reported the use of thermal oxidation method to remove the amorphous carbon layer, but this method has a long etching time, a narrow process temperature window, and more importantly, a high-temperature environment that can easily damage the diamond body, making the method severely limited in the regulation of the mechanical properties of diamond. SUMMARY

[0005] In view of the problems in the prior art, the application provides a method for improving the elastic limit of micro-nano scale diamond, thereby solving the technical problem that the amorphous damage layer generated during the FIB processing of diamond samples affects the elastic strain properties of diamond.

[0006] The application is realized by the following technical solutions: A method for improving the elastic limit of micro- and nano-scale diamond is proposed by controlling the elastic modulus and elastic strain of diamond by adjusting the thickness of the amorphous layer on the diamond surface.

[0007] Preferably, the process of controlling the thickness of the amorphous layer on the diamond surface specifically involves controlling the thickness of the amorphous layer on the diamond surface through a plasma etching process.

[0008] Preferably, the plasma is oxygen plasma.

[0009] Preferably, when using oxygen plasma etching to control the thickness of the amorphous layer on the diamond surface, the power of the oxygen plasma generator is 35~45W, and the processing time is 0~30min, not 0min.

[0010] Preferably, when the thickness of the amorphous layer on the diamond surface is controlled by the oxygen plasma etching process, the oxygen pressure in the oxygen plasma generator chamber is 35~45 Pa.

[0011] Preferably, when using oxygen plasma etching to control the thickness of the amorphous layer on the diamond surface, the etching temperature is room temperature.

[0012] Preferably, when using oxygen plasma etching process to control the thickness of the amorphous layer on the diamond surface, the power of the oxygen plasma generator is 40W, the processing time is 5~25min, and the oxygen pressure in the oxygen plasma generator chamber is 40Pa.

[0013] Preferably, the diamond is a nanoscale diamond, with a length of 200~2000nm, a width of 50~400nm, and a thickness of 50~400nm.

[0014] Preferably, the nanoscale diamond is prepared by focused ion beam processing.

[0015] Preferably, the thickness of the amorphous layer on the surface of the nanoscale diamond is controlled to be 0~25nm, the elastic modulus of the nanoscale diamond is controlled to be 500~1000GPa, and the strain is controlled to be 6%~12.2%.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a method for improving the elastic limit of micro / nano-scale diamond. This method utilizes oxygen plasma etching to precisely remove the amorphous damage layer remaining after focused ion beam processing. By strictly controlling parameters such as etching power and gas pressure, excessive etching damage to the diamond substrate can be avoided, keeping the amorphous layer thickness within a controllable range. This allows for stable control of the elastic modulus within 500–1000 GPa and strain within 6%–12.2%. This method not only eliminates the destructive effect of the original amorphous damage layer on the elastic limit but also optimizes elastic properties through directional control of the amorphous layer thickness, fundamentally solving the technical problem of the amorphous damage layer affecting the elastic limit of diamond caused by focused ion beam processing. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a transmission electron microscope image of the tensile testing process of the PI 95 nanomechanical testing system in this invention, showing the tensile testing process. Figure 2 The elastic strain changes of the specimen in Comparative Example 1 during the tensile test (a) and the elastic strain changes of the specimen in Example 2 during the tensile test (b) are shown. Figure 3 The elastic modulus and elastic strain test results are for the nanoscale diamond sample prepared by FIB process in Comparative Example 1 and the nanoscale diamond samples prepared in Examples 1-2 after oxygen plasma treatment. Figure 4 The thickness test results of the non-film layer on the surface of the untreated nanodiamond samples and the nanodiamond samples after plasma treatment in Examples 3-4 of this invention; Figure 5 The thickness of the amorphous film layer on the surface of the diamond samples prepared in Examples 5-6 of this invention before oxygen plasma treatment, and after oxygen plasma treatment for 10 min and 20 min. Figure 6 This invention relates the thickness of the amorphous film on the surface of a diamond sample and the elastic strain under different oxygen plasma treatment states (completely clean, treated, untreated). Detailed Implementation

[0019] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0020] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0021] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0022] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0023] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0024] This invention provides a method for improving the elastic limit of diamond at the micro-nano scale. This method controls the elastic modulus and elastic strain of diamond by adjusting the thickness of the amorphous layer on the diamond surface.

[0025] More specifically, the process of controlling the thickness of the amorphous layer on the diamond surface involves controlling the thickness of the amorphous layer through plasma etching to achieve controllable nanoscale control. The core technical idea is to precisely control the thickness of the amorphous layer on the diamond surface, thereby achieving directional control of the elastic modulus and elastic strain of the diamond, and significantly improving its elastic limit. While micro / nanoscale diamond possesses inherent advantages such as ultra-high hardness and excellent thermal conductivity, it is prone to elastic failure due to surface defects under extreme mechanical environments. This method, by constructing a controllable surface amorphous layer structure, can both compensate for the adverse effects of surface defects on mechanical properties and optimize the overall elastic performance through the synergistic effect of the amorphous layer and the crystalline substrate, providing technical support for the demand for high-performance diamond components in fields such as micro / nano electromechanical systems and precision sensing.

[0026] The plasma used is oxygen plasma. Specifically, the process of controlling the thickness of the amorphous layer on the diamond surface is achieved using plasma etching. This process features high etching precision, minimal surface damage, and easily controllable process parameters. It can precisely control the uniformity of the amorphous layer thickness, avoiding problems such as increased surface roughness and crystal structure damage caused by traditional mechanical processing or chemical etching methods, thus ensuring that the inherent superior performance of the diamond substrate is not significantly affected. The core reason for choosing oxygen plasma is that it has extremely high reactivity, capable of reacting with carbon elements on the diamond surface to generate gaseous CO or CO2, which then detaches from the surface, achieving precise etching and transformation of the surface crystal structure. Simultaneously, oxygen plasma etching does not introduce other impurity elements into the diamond surface, ensuring the purity of the amorphous layer and avoiding the negative impact of impurity doping on the mechanical properties of diamond. Compared to other plasmas such as argon and nitrogen, oxygen plasma has stronger etching selectivity and superior amorphization conversion efficiency on the diamond surface.

[0027] When using oxygen plasma etching to control the thickness of the amorphous layer on the diamond surface, the power of the oxygen plasma generator is 35~45W, the processing time is 0~30min (excluding 0min), the oxygen pressure in the oxygen plasma generator chamber is 35~45Pa, and the etching temperature is room temperature. In other words, to ensure controllable and uniform amorphous layer thickness without damaging the diamond substrate crystal structure, strict limitations are imposed on the process parameters when using oxygen plasma etching to control the thickness of the amorphous layer on the diamond surface: the power of the oxygen plasma generator is set to 35~45W. This power range ensures sufficient activity of the oxygen plasma to achieve surface etching and amorphization, while avoiding excessively high power leading to an excessively fast etching rate and difficulty in controlling the amorphous layer thickness, or excessively low power leading to low etching efficiency and poor amorphous layer uniformity; the processing time is 0~30min (excluding 0min). If the processing time is too long, the thickness of the amorphous layer will exceed the controllable range, or even over-etch and damage the diamond substrate. Therefore, the maximum processing time is limited to ensure that the thickness of the amorphous layer is within the target range. The oxygen pressure in the oxygen plasma generator chamber is controlled at 35~45Pa. This pressure range can ensure that the oxygen plasma is evenly distributed in the chamber, so that the etching effect on each area of ​​the diamond surface is consistent, thereby ensuring the uniformity of the amorphous layer thickness. The etching temperature is set at room temperature, which eliminates the need for additional heating or cooling equipment, reduces the complexity and cost of the process, and avoids the phase transition of the diamond crystal structure caused by the high temperature environment, which would affect its inherent mechanical properties.

[0028] In a preferred embodiment, when using oxygen plasma etching to control the thickness of the amorphous layer on the diamond surface, the oxygen plasma generator has a power of 40W, a processing time of 5-25 minutes, and an oxygen pressure of 40Pa within the oxygen plasma generator chamber. This set of parameters represents the optimal combination obtained through multiple orthogonal experiments. Under these parameters, the activity and distribution of the oxygen plasma achieve the best balance, enabling the formation of a uniform, high-purity amorphous layer on the diamond surface while minimizing the impact on the substrate's crystal structure. Testing shows that diamonds treated with these parameters exhibit the most significant improvement in elastic limit compared to untreated samples, and the process demonstrates strong stability and good repeatability, making it suitable for large-scale applications.

[0029] Preferably, the diamond is nanoscale diamond, with a length of 200-2000 nm, a width of 50-400 nm, and a thickness of 50-400 nm. This size range of nanoscale diamond is chosen primarily based on two considerations: Firstly, diamond within this size range retains the size effect of nanomaterials, enabling a significant improvement in the elastic limit through surface amorphous layer control, while also possessing sufficient structural integrity and mechanical load-bearing capacity to meet the practical application requirements of micro / nano devices. Secondly, this size range has a high degree of precision matching with existing micro / nano fabrication processes, facilitating large-scale fabrication and subsequent device integration. If the size is too large, it is difficult to demonstrate the performance advantages of the micro / nano scale, and the difficulty of surface amorphous layer control increases; if the size is too small, it will result in insufficient mechanical strength, making it difficult to withstand the mechanical loads in practical applications.

[0030] Furthermore, the nanoscale diamond in this invention is fabricated using focused ion beam (FIP) technology. FIP technology offers advantages such as high processing precision, strong controllability, and the ability to process complex three-dimensional structures. The specific process involves using high-quality diamond bulk as raw material. First, a mask representing the target pattern is prepared on the diamond surface using photolithography. Then, a focused ion beam is used to precisely etch the diamond, removing material outside the mask-covered area, ultimately obtaining a nanoscale diamond structure that meets the required dimensions. This process can precisely control the dimensional accuracy of the nanoscale diamond while ensuring low surface roughness, laying a solid foundation for the precise control of the subsequent amorphous layer. Compared to traditional chemical mechanical polishing (CMP) and laser etching processes, FIP processing effectively reduces surface defects in diamond, further enhancing its mechanical performance potential.

[0031] This method adjusts the mechanical properties of diamond by controlling the thickness of the amorphous layer on the diamond surface after FIB processing, reduces the deformation incompatibility between the amorphous film and diamond caused by the material modulus, and significantly improves fracture resistance and mechanical stability.

[0032] In this invention, the thickness of the amorphous layer on the surface of the nanoscale diamond is controlled to be 0~25nm, the elastic modulus of the nanoscale diamond is controlled to be 500~1000GPa, and the strain is controlled to be 6%~12.2%. This controllable range can meet the differentiated requirements of diamond elastic properties in different application scenarios, thereby realizing the customized design and application of diamond components.

[0033] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0034] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0035] Comparative Example 1 A nanoscale diamond sample with dimensions of 800 nm in length, 150 nm in width, and 150 nm in thickness

[001] was fabricated using a focused ion beam microscope (FIB). A 25 nm thick amorphous film remained on the surface of the nanoscale sample. The diamond sample was then placed in a JEM 2100F transmission electron microscope, and an in-situ tensile test was performed using a Bruker PI 95 nanomechanical testing system. The elastic modulus of the nanoscale diamond was measured to be 550 GPa, and the elastic strain was 6.88%.

[0036] In this invention, "elastic modulus" reflects a material's ability to resist elastic deformation, i.e., its stiffness. A higher value indicates greater resistance to compression or stretching. A high elastic modulus allows diamond to withstand high stresses in micro / nanoelectronic devices without easily deforming. The theoretical elastic modulus of diamond is approximately 900-1000 GPa, but the experimental value in this comparative example is lower due to the 25 nm thick amorphous carbon layer on the sample surface. Amorphous carbon has a lower elastic modulus (typically 100-500 GPa), and its presence reduces the overall measured value and may introduce interfacial stress or defects, affecting measurement accuracy.

[0037] In this invention, "elastic strain" refers to the recoverable deformation that occurs when a material is subjected to external force. The mechanism of elastic strain at the atomic level is that the external force causes a slight change in the interatomic spacing within the material, but the chemical bonds between atoms are not broken. Therefore, when the external force is removed, the interatomic interaction forces restore the material to its original state.

[0038] In this invention, "elastic limit" refers to the maximum stress at which a material can undergo fully recoverable elastic deformation under stress. Exceeding this limit, the material enters an irreversible plastic deformation stage and cannot return to its original state even after unloading. According to Hooke's Law, σ... e =E·ε e , where σ e ε is the elastic limit, which refers to the maximum stress a material can withstand during the elastic deformation stage. Beyond this value, the material will undergo irreversible plastic deformation. E is the elastic strain, corresponding to the strain value at the elastic limit, i.e., the relative deformation of the material at the elastic limit. e Elastic modulus reflects a material's ability to resist elastic deformation. That is, the elastic limit is equal to the product of the elastic modulus and the elastic strain.

[0039] In this invention, “

[001] direction” is a symbol used in crystallography to describe the direction of the arrangement of atoms in a crystal lattice, representing the positive z-axis direction or equivalent crystal axis direction of a cubic crystal cell.

[0040] Example 1 A nanoscale diamond sample with dimensions of 800 nm in length, 150 nm in width, and 150 nm in thickness was processed using a focused ion beam microscope (FIB). The sample surface of the nanoscale sample had a residual amorphous film with a thickness of 25 nm.

[0041] Then, an oxygen plasma generator with a power of 40W and an oxygen pressure of 40Pa was used to partially process the amorphous film layer, and the thickness of the amorphous film layer after processing was 6.5nm.

[0042] The treated diamond sample was placed in a JEM 2100F transmission electron microscope and an in-situ tensile test was performed using a Bruker PI 95 nanometer mechanical testing system. The elastic modulus of the treated diamond was measured to be 784 GPa and the elastic strain was 12.2%.

[0043] Example 2 A nanoscale diamond sample with dimensions of 800 nm in length, 150 nm in width, and 150 nm in thickness was processed using a focused ion beam microscope (FIB). The sample surface of the nanoscale sample had a residual amorphous film layer with a thickness of 25 nm.

[0044] Then, an oxygen plasma generator with a power of 40W and an oxygen pressure of 40Pa was used to completely process the amorphous film layer (~0nm), that is, to retain the thickness of the amorphous film layer at about 0nm.

[0045] The treated diamond sample was placed in a JEM 2100F transmission electron microscope and an in-situ tensile test was performed using a Bruker PI 95 nanometer mechanical testing system. The elastic modulus of the treated diamond was measured to be 953 GPa and the elastic strain was 7.66%.

[0046] Example 3 A nanoscale diamond sample with dimensions of 800 nm in length, 150 nm in width, and 150 nm in thickness was processed using a focused ion beam microscope (FIB). The sample surface of the nanoscale sample had a residual amorphous film layer with a thickness of 30 nm.

[0047] Then, the amorphous film was treated with an oxygen plasma generator with a power of 40W and an oxygen pressure of 40Pa for 10 minutes. After treatment, the thickness of the amorphous film on the surface was about 15nm.

[0048] The treated diamond sample was placed in a JEM 2100F transmission electron microscope and an in-situ tensile test was performed using a Bruker PI 95 nanometer mechanical testing system. The elastic modulus of the treated diamond was measured to be 820 GPa and the elastic strain was 8.5%.

[0049] Example 4 A nanoscale diamond sample with dimensions of 800 nm in length, 150 nm in width, and 150 nm in thickness was processed using a focused ion beam microscope (FIB). The sample surface of the nanoscale sample had a residual amorphous film layer with a thickness of 30 nm.

[0050] Then, the amorphous film was treated with an oxygen plasma generator with a power of 40W and an oxygen pressure of 40Pa for 20 minutes. After treatment, the thickness of the amorphous film on the surface was about 0.6nm.

[0051] The treated diamond sample was placed in a JEM 2100F transmission electron microscope and an in-situ tensile test was performed using a Bruker PI 95 nanometer mechanical testing system. The elastic modulus of the treated diamond was measured to be 980 GPa and the elastic strain was 7.0%.

[0052] Example 5 A nanoscale diamond sample with dimensions of 800 nm in length, 150 nm in width, and 150 nm in thickness was processed using a focused ion beam microscope (FIB). The sample surface of the nanoscale sample had a residual amorphous film layer with a thickness of 20 nm.

[0053] Then, an oxygen plasma generator with a power of 40W and an oxygen pressure of 40Pa was used to treat the amorphous film layer for 10 minutes. After treatment, the thickness of the amorphous film layer on the surface was about 7nm.

[0054] Example 6 A nanoscale diamond sample with dimensions of 800 nm in length, 150 nm in width, and 150 nm in thickness was processed using a focused ion beam microscope (FIB). The sample surface of the nanoscale sample had a residual amorphous film layer with a thickness of 20 nm.

[0055] Then, the amorphous film was treated with an oxygen plasma generator with a power of 40W and an oxygen pressure of 40Pa for 20 minutes. After treatment, the thickness of the amorphous film on the surface was about 0.7nm.

[0056] Example 7 A nanoscale diamond sample with dimensions of 500 nm in length, 100 nm in width, and 100 nm in thickness was processed using a focused ion beam microscope (FIB). The sample surface of the nanoscale sample had a residual amorphous film layer with a thickness of 20 nm.

[0057] Then, the amorphous film was treated at room temperature using an oxygen plasma generator with a power of 35W and an oxygen pressure of 35Pa for 5 minutes. After treatment, the thickness of the amorphous film on the surface was 16nm.

[0058] The treated diamond sample was placed in a JEM 2100F transmission electron microscope and an in-situ tensile test was performed using a Bruker PI 95 nanometer mechanical testing system. The elastic modulus of the treated diamond was measured to be 805 GPa and the elastic strain was 8.2%.

[0059] Example 8 A nanoscale diamond sample with dimensions of 1500 nm in length, 300 nm in width, and 300 nm in thickness was processed using a focused ion beam microscope (FIB). The sample surface of the nanoscale sample had a residual amorphous film layer with a thickness of 20 nm.

[0060] Then, the amorphous film was treated at room temperature using an oxygen plasma generator with a power of 45W and an oxygen pressure of 45Pa for 20 minutes. After treatment, the thickness of the amorphous film on the surface was 0.4nm.

[0061] The treated diamond sample was placed in a JEM 2100F transmission electron microscope and an in-situ tensile test was performed using a Bruker PI 95 nanometer mechanical testing system. The elastic modulus of the treated diamond was measured to be 950 GPa and the elastic strain was 7.2%.

[0062] Figure 1 This is a transmission electron microscope (TEM) image of the tensile testing process of the PI 95 nanomechanical testing system in this invention. During the tensile test, the sample to be tested is fixed on a special sample holder and stretched under the observation of a transmission electron microscope using a diamond puller. Figure 2 The figures show the elastic strain changes of the Comparative Example 1 specimen (a) and the Example 2 specimen during the tensile test (b). As can be seen, during the tensile test, the Comparative Example 1 specimen showed relatively gradual deformation as the strain increased from 0% to 6.8%, eventually fracturing, indicating a relatively limited elastic strain capacity. In contrast, the Example 2 specimen exhibited different deformation characteristics during the tensile test from 0% strain to 7.6% strain, demonstrating better elastic deformation capacity under the same strain increment. The comparison shows that the Example 2 specimen, after complete oxygen plasma treatment, exhibited altered mechanical behavior and improved elastic limit properties during the tensile test compared to the Comparative Example 1 specimen, demonstrating the positive effect of oxygen plasma treatment on improving the tensile properties of nanoscale diamond specimens.

[0063] Figure 3 The figures show the elastic modulus and elastic strain test results of the nanoscale diamond sample prepared by FIB processing in Comparative Example 1 and the samples prepared by oxygen plasma treatment in Examples 1 and 2. As can be seen from the figures, the elastic modulus of the untreated sample is 550 GPa, the elastic strain is 6.88%, and its elastic limit is 37.84 GPa. In Example 1, after partial oxygen plasma treatment, the amorphous film thickness was reduced to 6.5 nm, the elastic modulus increased to 784 GPa, the elastic strain significantly increased to 12.2%, and its elastic limit was 95.65 GPa. In Example 2, after complete treatment, the amorphous film was almost completely removed, the elastic modulus further increased to 953 GPa, but the elastic strain slightly decreased to 7.66%, and its elastic limit was 73.00 GPa. This method effectively removes the amorphous film layer on the surface or changes its structure through oxygen plasma treatment. Therefore, the elastic limit of diamond can be effectively adjusted through oxygen plasma treatment. This method has a significant effect on optimizing the mechanical properties of nanoscale diamond, and provides the possibility for its application in high-performance electronic devices and other fields.

[0064] Figure 4The figures show the thickness test results of the amorphous film layer on the surface of the untreated nanodiamond samples and the nanodiamond samples treated with plasma in Examples 3-4 of this invention. As can be seen from the figures, as the oxygen plasma treatment time increased from 10 min to 20 min, the thickness of the amorphous film layer on the surface of the nanodiamond samples decreased significantly, from about 15 nm to nearly 0.6 nm. Therefore, oxygen plasma treatment has a significant impact on both the thickness of the amorphous film layer and the elastic properties of nanodiamonds.

[0065] Figure 5 The thickness of the amorphous film on the surface of the diamond samples prepared in Examples 5-6 of this invention before oxygen plasma treatment, and after oxygen plasma treatment for 10 min and 20 min, is shown in the figure. Before treatment, the thickness of the amorphous film is 20 nm. After treatment for 10 min, the amorphous film is 7 nm. After treatment for 20 min, the amorphous film is completely removed. The thickness of the amorphous film on the surface of nanodiamond can be effectively controlled by plasma treatment.

[0066] in addition, Figure 6 This paper presents the relationship between the thickness of the amorphous film on the surface of diamond samples and their elastic strain under different oxygen plasma treatment states (completely clean, treated, and untreated). As shown in the figure, the untreated diamond samples have a relatively large amorphous film thickness, approximately 20 nm, and their elastic strain is generally low, around 6%–7%. After oxygen plasma treatment, the elastic strain exhibits different characteristics depending on the thickness of the amorphous film. Samples with completely cleaned amorphous film (thickness approaching 0 nm) also have low elastic strain, approximately 7%. Controlling the thickness of the amorphous film within a certain range can effectively regulate the elastic strain of the diamond, even bringing it close to the theoretical maximum value (around 13%). This indicates that oxygen plasma treatment has a significant impact on the thickness of the amorphous film on the diamond surface, thus affecting its elastic strain performance. In practical applications, other factors such as the elastic modulus can be considered comprehensively to fully evaluate the improvement effect of oxygen plasma treatment on diamond performance.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for improving the elastic limit of micro / nano-scale diamond, characterized in that, The elastic modulus and elastic strain of diamond can be controlled by adjusting the thickness of the amorphous layer on the diamond surface.

2. The method for improving the elastic limit of micro / nano-scale diamond according to claim 1, characterized in that, The process of controlling the thickness of the amorphous layer on the diamond surface is specifically as follows: the thickness of the amorphous layer on the diamond surface is controlled by plasma etching process.

3. The method for improving the elastic limit of micro / nano-scale diamond according to claim 2, characterized in that, The plasma is oxygen plasma.

4. The method for improving the elastic limit of micro / nano-scale diamond according to claim 3, characterized in that, When using oxygen plasma etching to control the thickness of the amorphous layer on the diamond surface, the power of the oxygen plasma generator is 35~45W, and the processing time is 0~30min, not 0min.

5. The method for improving the elastic limit of micro / nano-scale diamond according to claim 3, characterized in that, When using oxygen plasma etching to control the thickness of the amorphous layer on the diamond surface, the oxygen pressure in the oxygen plasma generator chamber is 35~45 Pa.

6. The method for improving the elastic limit of micro / nano-scale diamond according to claim 3, characterized in that, When using oxygen plasma etching to control the thickness of the amorphous layer on the diamond surface, the etching temperature is room temperature.

7. The method for improving the elastic limit of micro / nano-scale diamond according to claim 3, characterized in that, When using oxygen plasma etching to control the thickness of the amorphous layer on the diamond surface, the power of the oxygen plasma generator is 40W, the processing time is 5~25min, and the oxygen pressure in the oxygen plasma generator chamber is 40Pa.

8. The method for improving the elastic limit of micro / nano-scale diamond according to claim 1, characterized in that, The diamond is a nanoscale diamond, with a length of 200~2000nm, a width of 50~400nm, and a thickness of 50~400nm.

9. A method for improving the elastic limit of micro / nano-scale diamond according to claim 8, characterized in that, The nanoscale diamond was prepared by focused ion beam processing.

10. A method for improving the elastic limit of micro / nano-scale diamond according to claim 8, characterized in that, The thickness of the amorphous layer on the surface of the nanoscale diamond is controlled to be 0~25nm, the elastic modulus of the nanoscale diamond is controlled to be 500~1000GPa, and the strain is controlled to be 6%~12.2%.

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