Method for measuring thickness of film on surface of crystal material

Abstract

The invention discloses a method for measuring the thickness of a surface film of a crystal material, which belongs to the technical field of precision measurement, and comprises the following steps: establishing a physical model of the crystal material, and calculating theoretical values of X-ray relative diffraction intensity of surface films with different thicknesses; the diffraction peak intensity ratio M of the surface film to the base material is used as a horizontal coordinate, the thickness d of the surface film is used as a vertical coordinate, and a relational expression between M and d is constructed according to data point fitting; carrying out X-ray diffraction scanning on the to-be-tested piece, extracting independent diffraction peak intensity, and correcting the independent diffraction peak intensity; according to the corrected independent diffraction peak intensity, a representative diffraction peak is selected, the diffraction peak intensity ratio is substituted into the relational expression, and the thickness of the corresponding surface film is calculated. The method can be used for measuring the thickness of metal, ceramic, organic and other crystal films on the surface of a crystal material, influence factors such as the initial state, preferred orientation, surface / interface roughness and the like of the material can not be considered, the method can be used for a plane / special-shaped surface, the applicability is high, and nondestructive testing is effectively carried out.

Description

Technical Field

[0001] This application belongs to the field of precision measurement technology, and in particular relates to a method for measuring the thickness of a thin film on the surface of a crystal material. Background Technology

[0002] In modern society, utensils, instruments, and equipment made of metals and alloys permeate every aspect of life. These items are easily corroded by environmental atmospheres and solutions during long-term storage, use, and service, causing structural changes, gradual performance degradation, and even material failure leading to accidents. To slow down the corrosion process, people usually coat metal surfaces or perform surface modification treatments. Corrosion and corrosion prevention have become important topics in the research and application of metallic materials. Non-destructive measurement of the thickness of corrosion layers and protective layers is a key step in studying material properties, optimizing process parameters, and evaluating product quality. Currently, common non-destructive measurement methods for thin film thickness include X-ray methods, eddy current methods, ultrasonic methods, and optical methods, each with its unique application scenarios and applicable scope.

[0003] The conventional X-ray diffraction substrate intensity method calculates film thickness by measuring the diffraction intensity I1 of the substrate before and after film coating. While simple, this method has significant limitations in obtaining accurate results. First, data on the substrate in its uncoated state is required, making it difficult to measure materials with existing films using this method. Second, the two measurement locations must perfectly coincide, and the preferred orientation and microstructure must remain consistent, which is difficult to achieve in most cases.

[0004] X-ray total internal reflection (XRR) measures film thickness by reflecting the oscillation period at the film surface and interface. This method offers high accuracy and is primarily used for measuring the thickness of epitaxially grown films on single-crystal substrates. However, this method places extremely high demands on the sample surface and interface, requiring a distinct interface between the film and the substrate, a certain difference in electron density between the two materials, and nanoscale roughness at the surface and interface—requirements that are difficult to meet for most samples.

[0005] Variable-angle X-ray diffraction (rocking curve method) calculates film thickness by measuring the effect of different absorption paths of X-rays within the film on the intensity of a single diffraction peak in the substrate. This method does not require the initial diffraction intensity of the substrate, but it is highly sensitive to the preferred orientation of the substrate and can only be used for the analysis of samples without a preferred orientation.

[0006] Reflectance spectroscopy measures film thickness by measuring the reflection of visible light at surfaces and interfaces. This method is fast, but it can only measure transparent films and cannot be used to measure opaque films.

[0007] The FIB combined with SEM method involves using focused ion beam sputtering to penetrate a thin film of approximately tens of micrometers in length on the sample surface, followed by direct observation of the film thickness using a scanning electron microscope. While this method allows for direct measurement of film thickness, it is a destructive method with low efficiency, expensive equipment, and is limited to small sample sizes, making it difficult to measure large workpieces. This method is typically used for comparison and verification of nondestructive testing techniques.

[0008] In summary, existing non-destructive testing techniques for measuring the thickness of thin films on the surface of crystalline materials are limited by factors such as the initial state of the sample, preferred orientation, and surface / interface roughness, and are not well applicable to the measurement of thin film thickness of crystalline materials. Summary of the Invention

[0009] This application aims to solve the technical problem of how to better apply the measurement of surface thin film thickness of crystalline materials. To this end, this application provides a method for measuring the surface thin film thickness of crystalline materials, which can be used to measure the thickness of crystalline thin films of metals, ceramics, organic materials, etc. on the surface of crystalline materials. It can disregard the influencing factors such as the initial state of the material, preferred orientation, and surface / interface roughness, and has strong applicability, effectively performing non-destructive testing of the surface thin film thickness of crystalline materials.

[0010] This application provides a method for measuring the thickness of a thin film on the surface of a crystalline material. The method is used to measure the thickness of the crystalline material, referred to as the test piece, and includes:

[0011] Establish a physical model of the substrate and surface thin film of the crystalline material, and calculate the theoretical values ​​of the relative X-ray diffraction intensity of the crystalline material corresponding to surface thin films of different thicknesses;

[0012] Plot the corresponding data points with the ratio of diffraction peak intensity M between the surface film and the substrate, and the thickness d of the surface film as one of the horizontal and vertical axes, respectively, and fit and construct the relationship between M and d.

[0013] X-ray diffraction scanning was performed on the test piece to extract the intensity of the independent diffraction peaks of the substrate and the surface thin film, and the intensity of the independent diffraction peaks was corrected.

[0014] Based on the corrected independent diffraction peak intensities of the substrate and the thin film, representative diffraction peaks are selected, and the ratio of the diffraction peak intensities of the surface thin film to those of the substrate is substituted into the formula to calculate the corresponding thickness of the surface thin film.

[0015] In some implementations, plotting the corresponding data points specifically includes:

[0016] From the theoretical values ​​of relative diffraction intensity, select typical diffraction peaks of the surface film and the substrate, or the sum of the intensities of multiple diffraction peaks, and calculate the ratio of the relative diffraction intensity of the surface film and the substrate.

[0017] List the thickness of the surface film and the corresponding ratio of the diffraction intensity to form data points. Plot the corresponding data points in the coordinate system with the ratio of the diffraction peak intensity M of the surface film to the substrate as the x-axis and the thickness d of the surface film as the y-axis.

[0018] In some implementations, the specific method for fitting the relationship between M and d is as follows: based on each data point, the least squares method is used to fit the theoretical curve.

[0019] In some implementations, after the relation is constructed, if an observable defect appears in the surface film, the relation is modified. During the modification, the actual measured value of the test piece is compared with the theoretical value, so that the curve corresponding to the relation is close to the curve corresponding to the actual measured value.

[0020] In some embodiments, when performing X-ray diffraction scanning on the test piece, if the test piece has a preferred orientation, the number of independent diffraction peaks covering the substrate and surface film in the scanning range is greater than or equal to 3; if the test piece does not have a preferred orientation, the number of independent diffraction peaks covering the substrate and surface film in the scanning range is greater than or equal to 1.

[0021] In some embodiments, extracting the independent diffraction peak intensities of the substrate and the surface film includes: extracting the independent diffraction peak intensities of the substrate and the surface film using software or calculation methods.

[0022] In some implementations, when extracting the independent diffraction peak intensities of the substrate and the surface film:

[0023] If software is used, the diffraction peak intensities of the substrate and the surface film are integrated, and the integrated intensity is taken as the independent diffraction peak intensity.

[0024] If a calculation method is used, the intensity of an independent diffraction peak is determined by multiplying the intensity value at the apex of the diffraction peak by the peak width at half the height of the diffraction peak.

[0025] In some implementations, and when correcting for the intensity of individual diffraction peaks, the following formula is used:

[0026] y i =a i x i / b

[0027] Among them, y i To correct the intensity of the independent diffraction peaks, x i Related to the initial intensity of the diffraction peak, the multiplicity factor, and the relative diffraction intensity factor, a i is a parameter related to the multiplicity factor, and b is a coefficient related to the relative diffraction intensity factor.

[0028] In some implementations, selecting a representative diffraction peak means that the selected diffraction peak is consistent with the diffraction peak selected when plotting the corresponding data points.

[0029] In some embodiments, the physical model includes a two-layer structure of a substrate and a surface film, or a multi-layer structure including a substrate and multiple surface films, or a multi-layer structure including a substrate, a hybrid layer, and a surface film; the surface film includes a nitride film, an oxide film, a metallic or non-metallic film.

[0030] As can be seen from the above technical solution, the beneficial effects of this application are as follows:

[0031] This application, through theoretical modeling and calculation, establishes theoretical curves for different surface film thicknesses and relative diffraction intensity ratios. Based on the curve fitting function corresponding to each data point, the X-ray diffraction scanning data of the test piece is processed. The intensity of independent diffraction peaks is corrected based on data comparison. Substituting the corrected data into the function, the surface film thickness is calculated, enabling rapid measurement and verification of surface film thickness. This transforms measurement from direct measurement into a correction problem between theoretical and actual measured values, making the measured value closer to the true value. By deriving and substituting the relationship, the surface film thickness can be determined. This technology plays a crucial role in various fields such as surface film thickness measurement, thickness uniformity assessment, and quantitative calculation of phase content, contributing significantly to process parameter optimization, film performance control, and product quality assurance. Therefore, this application can be used to measure the thickness of crystalline films on the surface of crystalline materials such as metals, ceramics, and organic materials. It disregards the influence of initial material state, preferred orientation, and surface / interface roughness, making it highly applicable and effective for non-destructive testing of surface film thickness in crystalline materials. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced one by one below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other embodiments and drawings can be obtained based on these drawings without creative effort. The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined. Therefore, the actual execution order may change according to the actual situation.

[0033] Figure 1 A schematic flowchart of an embodiment of the method for measuring the thickness of a thin film on the surface of a crystalline material according to the present invention is shown;

[0034] Figure 2 A schematic diagram of the X-ray path in a crystalline material is shown.

[0035] Figure 3 A schematic diagram illustrating an embodiment of the statistical data points and fitting of the present invention is shown;

[0036] Figure 4 A comparison diagram of the measurement results of two nitride layer thicknesses and the measurement results of the destructive method in embodiments of the present invention is shown;

[0037] Figure 5 A comparison chart showing the measurement results of the corrosion layer thickness in an embodiment of the present invention and the measurement results of the destructive method is shown. Detailed Implementation

[0038] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application. The described embodiments are only a part of the embodiments of this application, not all of them. Based on the embodiments in this application, they can be arranged and designed in various different configurations. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] This application is described below with reference to the accompanying drawings and specific embodiments:

[0040] Please refer to Figure 1 The embodiments of this application provide a method for measuring the thickness of a thin film on the surface of a crystal material. The method is used to measure the crystal material, which is referred to as the test piece. The crystal material in this application refers to a polycrystalline material. Due to the large grain size or preferred growth of the polycrystalline material, the diffraction intensity of a certain diffraction plane deviates significantly from the diffraction intensity of a random orientation.

[0041] Measurement methods include:

[0042] S1. Establish a physical model of the substrate and surface thin film of the crystalline material. Based on the physical model, calculate the theoretical values ​​of the relative X-ray diffraction intensity of the crystalline material corresponding to surface thin films of different thicknesses. The relative diffraction intensity can be calculated using the relative intensity ratio method. For example... Figure 2Let I0 be the incident X-ray, I1 be the incident X-ray in the surface thin film, I2 be the diffracted X-ray in the surface thin film, I be the diffracted X-ray of the crystalline material, α be the angle between the incident X-ray and the surface thin film, β be the angle between the diffracted X-ray and the surface thin film, and 2θ be the angle between the incident X-ray and the diffracted X-ray. Since the diffraction intensity and attenuation of the crystalline material under X-ray irradiation are related to the path of the X-rays within the material, in a bilayer structure of thin film and substrate, on the one hand, the diffraction peak intensity of the thin film is directly related to its thickness; on the other hand, due to the attenuation of X-rays by the surface thin film, the diffraction intensity of the substrate is also related to the thickness of the surface thin film. Moreover, these two influences have a definite functional relationship, based on which the thickness of the surface thin film can be measured non-destructively.

[0043] S2. Select typical diffraction peaks for the surface film and the substrate. Typical diffraction peaks are independent diffraction peaks that can represent the relative intensity of the film and the substrate. Determine the thickness of the surface film and the ratio of the relative diffraction intensity of the surface film and the substrate diffraction peaks as data points. Plot the corresponding data points with the ratio of the diffraction peak intensity M of the surface film and the thickness d of the surface film as the ordinate, or with M as the ordinate and d as the abscissa. Fit each data point to determine the corresponding curve and construct the relationship between M and d. The curve corresponding to this relationship is called the working curve. The working curve is the curve corresponding to the functional relationship that combines theoretical calculations and actual verification. The relationship is related to the parameter selection in the working curve plotting process. The working curve can be non-linear or linear.

[0044] S3. Perform X-ray diffraction (XRD) scan on the test piece. Before scanning, inspect the surface of the test piece to confirm that there are no contaminants. The commonly used mode is conventional symmetrical scanning (other scanning methods are also possible, but the theoretical calculations need to be modified accordingly). The scan should include the intensity of multiple independent diffraction peaks of the substrate and surface film as much as possible. After scanning, extract the intensity of the independent diffraction peaks of the substrate and surface film and correct the intensity of the independent diffraction peaks.

[0045] S4. Based on the corrected independent diffraction peak intensities of the substrate and the film, select a representative diffraction peak. A representative diffraction peak refers to a typical diffraction peak among multiple diffraction peaks, such as the diffraction peak with the highest peak value. Calculate the ratio of the diffraction peak intensities of the surface film to that of the substrate, and substitute it into the relationship in step S2 to calculate the thickness of the corresponding surface film.

[0046] Existing non-destructive testing techniques, limited by conditions such as initial sample state, preferred orientation, and surface / interface roughness, are not well-suited for measuring the thickness of thin films in crystalline materials. This application, through theoretical modeling and calculation, establishes theoretical curves relating different surface film thicknesses to relative diffraction intensity ratios. Based on the curve fitting function corresponding to each data point, the X-ray diffraction scan data of the test piece is processed. The intensity of independent diffraction peaks is corrected based on data comparison. Substituting the corrected data into the function, the surface film thickness is calculated, enabling rapid measurement and verification of surface film thickness. This transforms measurement from direct measurement into a correction problem between theoretical and actual measured values, ensuring the measured value approximates the true value. By deriving and substituting the relationship, the surface film thickness can be determined. This technology plays a crucial role in various fields such as surface film thickness measurement, thickness uniformity assessment, and quantitative calculation of phase content, contributing significantly to process parameter optimization, film performance control, and product quality assurance. Therefore, this application can be used to measure the thickness of crystalline thin films such as metals, ceramics, and organic materials on the surface of crystalline materials. It can disregard factors such as the initial state of the material, preferred orientation, and surface / interface roughness, making it highly applicable and effective for non-destructive testing of the surface thin film thickness of crystalline materials.

[0047] This application utilizes conventional XRD pattern data to obtain accurate results. Besides measuring surface film thickness, it can also be used for quantitative analysis of mixed phases, expanding the application areas of XRD technology and demonstrating significant potential in scientific research, industry, and commerce. This application also imposes no additional restrictions on the sample's transmittance, conductivity, or flatness, further broadening the functional scope of X-ray diffraction. Furthermore, based on theoretical X-ray diffraction data, this application can refer to X-ray diffraction PDF databases (PDF: Powder Diffraction Card Database) or relevant quantitative simulation software to obtain the relative diffraction spectra or relative diffraction peak intensities of the surface film and substrate. Then, using X-ray diffraction scanning patterns and based on diffraction and absorption theories, the individual diffraction peak intensities are determined, ultimately calculating the surface film thickness. This approach offers advantages such as being non-destructive, accurate, efficient, and reliable.

[0048] In some implementations, plotting the corresponding data points specifically includes:

[0049] From the theoretical values ​​of relative diffraction intensity, select typical diffraction peaks of the surface film and the substrate (select the strongest peak among the independent diffraction peaks), or the sum of the intensities of multiple diffraction peaks, and calculate the ratio of the relative diffraction intensity of the surface film and the substrate; that is, use a typical single diffraction peak or the sum of multiple diffraction peaks.

[0050] List the thickness of the surface film and the corresponding ratio of the diffraction intensity to form data points. Plot the corresponding data points in the coordinate system with the ratio of the diffraction peak intensity M of the surface film to the substrate as the x-axis and the thickness d of the surface film as the y-axis.

[0051] In some implementations, the specific method for fitting and constructing the relationship between M and d is as follows: based on each data point (the ratio of the relative diffraction intensity of the surface film and the substrate diffraction peaks, and the thickness of the surface film) as the points in the above coordinate system, the least squares method is used to fit the theoretical curve to obtain the functional relationship, such as:

[0052] d = A + B / (1 + M) P (1)

[0053] Where d is the thickness of the surface film; A, B and P are coefficients obtained by fitting, which are related to the selected thickness range, intensity ratio, etc.; M is the ratio of the diffraction peak intensity of the surface film to that of the substrate.

[0054] In some implementations, after establishing the relationship, if observable defects appear within the surface film, such as porosity or voids, the relationship is modified. This modification involves comparing experimental measurement data and actual values ​​with theoretical values ​​from a small number of typical test samples to verify and correct the functional relationship. This ensures the curve corresponding to the relationship closely matches the curve corresponding to the actual measured value, establishing a functional relationship that better matches the actual situation. This results in more accurate applications of the relationship. If no defects are observed, no modification is needed, and the functional relationship from step S2 can be used to calculate the surface film thickness.

[0055] In some embodiments, when performing X-ray diffraction scanning on the test piece, if the test piece has a preferred orientation, the number of independent diffraction peaks covering the substrate and surface film in the scanning range is greater than or equal to 3. During scanning, the scanning range should include data from 3 or more independent diffraction peaks of the substrate and surface film, typically 4-7. If the test piece does not have a preferred orientation, the number of independent diffraction peaks covering the substrate and surface film in the scanning range is greater than or equal to 1, i.e., the number can be appropriately reduced.

[0056] In some embodiments, extracting the independent diffraction peak intensities of the substrate and the surface film includes: extracting the independent diffraction peak intensities of the substrate and the surface film using software or calculation methods.

[0057] In some implementations, when extracting the independent diffraction peak intensities of the substrate and the surface film:

[0058] If software is used, the diffraction peak intensities of the substrate and the surface film are integrated, and the integrated intensity is used as the independent diffraction peak intensity; software such as Highscore and Jade can be used.

[0059] If a calculation method is used, the intensity of an independent diffraction peak is determined by multiplying the intensity value at the apex of the diffraction peak by the peak width at half the peak height, i.e., peak height multiplied by half the peak width.

[0060] In some implementations, the following formula is used when obtaining independent diffraction peak data for the substrate and surface film, and when correcting the intensity of the independent diffraction peaks:

[0061] y i =a i x i / b (2)

[0062] Among them, y i To correct the intensity of the independent diffraction peaks, x i Related to the initial intensity of the diffraction peak, the multiplicity factor, and the relative diffraction intensity factor, a i is a parameter related to the multiplicity factor, and b is a coefficient related to the relative diffraction intensity factor.

[0063] In some implementations, selecting a representative diffraction peak means that the selected diffraction peak is consistent with the diffraction peak selected when plotting the corresponding data points.

[0064] In some embodiments, the physical model includes a two-layer structure of a substrate and a surface film, or a multi-layer structure including a substrate and multiple surface films, or a multi-layer structure including a substrate, a hybrid layer, and a surface film; the surface film includes a nitride film, an oxide film, a metallic or non-metallic film.

[0065] In some implementations, in step S2 above, corresponding data points are plotted, and each data point is fitted to determine the corresponding curve. The data points are shown in Table 1 below. Based on the data points in Table 1, a curve is plotted in the coordinate system and fitted with the relationship expression, as shown below. Figure 3 As shown (the thickness range varies depending on the material of the surface film).

[0066] Table 1. Diffraction intensity ratio between surface film and substrate, and statistical table of surface film thickness.

[0067] Diffraction intensity ratio Thickness (nm) Diffraction intensity ratio Thickness (nm) 0.03 20 5.18 800 0.16 100 6.77 900 0.42 200 8.72 1000 0.8 300 11.09 1100 1.32 400 14 1200 1.99 500 17.58 1300 2.84 600 21.99 1400 3.89 700 27.49 1500

[0068] The embodiments of this application are as follows:

[0069] Example 1: Measurement of nitrided layer thickness on the surface of a certain material

[0070] 1) Calculate the theoretical diffraction patterns of the substrate with different thicknesses of nitride layers, select the strongest independent diffraction peaks of the nitride and the substrate with different thicknesses of nitride layers, and calculate and obtain a series of relative intensity ratios between the two.

[0071] 2) Plot the theoretical Md curve with the relative intensity ratio M of the diffraction peaks as the abscissa and the nitride layer thickness d as the ordinate (see...). Figure 3 By fitting the data, the functional relationship d = 2900 - 3000 / (1 + M) is obtained. 0.6 );

[0072] 3) The sample was scanned using an X-ray diffractometer to obtain XRD data. In this example, the scanning range contained 4 and 7 independent diffraction peaks for the thin film and the substrate, respectively.

[0073] 4) Process the data using Highscore software to obtain the integrated intensity of the diffraction peaks of the thin film and the substrate;

[0074] 5) Use formula (2) to optimize the selected diffraction peaks of the film and substrate to obtain corrected intensity data;

[0075] 6) Substitute the corrected intensity data into the functional relationship established in step 2 above to calculate the corresponding film thickness d (the results are listed in...). Figure 4 );

[0076] 7) In this example, the FIB+SEM method was used to perform destructive measurement of the sample film thickness (see results). Figure 4 This is used to verify or correct the functional relationship in step 2. Wherein, FIB: Focused Ion Beam, SEM: Scanning Electron Microscope.

[0077] from Figure 4 As can be seen, the nitride layer thickness measured by this method is very close to the actual thickness (destructive measurement value). Therefore, the theoretical function relationship (step 2) established in this example does not need further correction (equivalent to the working curve). This function relationship can be used to perform non-destructive measurement of the nitride layer thickness on the same material surface or to inspect products with the same process.

[0078] Example 2: Measurement of oxide layer thickness on the surface of a certain material

[0079] After long-term corrosion, the material forms an oxide layer of a certain thickness on its surface. The thickness measurement steps are similar to those in Example 1, but the theoretical relationship needs further modification.

[0080] 1) Calculate the theoretical diffraction patterns of the material surface when it is covered with oxide layers of different thicknesses. Select the second strongest diffraction peaks of the oxide and the substrate when the oxide layers are of different thicknesses, and calculate and obtain a series of relative intensity ratios between the two.

[0081] 2) Plot the theoretical Md curve with the relative intensity ratio M of the diffraction peaks as the abscissa and the nitride layer thickness d as the ordinate (see...). Figure 3 By fitting the data, the corresponding functional relationship can be obtained (similar to Example 1);

[0082] 3) The sample was scanned using an X-ray diffractometer to obtain XRD data. The scanning range contained 5 and 6 independent diffraction peaks for the substrate and thin film, respectively.

[0083] 4) Process the data using Highscore software to obtain the integrated intensity of the diffraction peaks of the thin film and the substrate;

[0084] 5) Use formula (2) to correct the measured diffraction peak intensity to obtain corrected data;

[0085] 6) Substitute the corrected data into the functional relationship established in step 2) to calculate the corresponding film thickness (the results are listed in...). Figure 5 );

[0086] 7) In this example, the FIB+SEM method was used to perform destructive measurement of the sample film thickness (see results). Figure 5 ), used to verify or correct theoretical curve functions.

[0087] from Figure 5 As can be seen, the calculation results of steps 1-6 differ somewhat from the measured values ​​of the destructive method. The main reason for the difference is that the functional relationship established in step 2 is a theoretical result, and the thickness value calculated from this functional relationship is the thickness under the condition of dense corrosion products, which is the ideal thickness and the intrinsic thickness; while the thickness measured by the destructive visualization method includes not only oxides but also their internal gaps and pores, which is the comprehensive thickness and the apparent thickness.

[0088] from Figure 5 As can be seen, the corrosion layer contains obvious interlayer gaps and pores, indicating loose tissue. Measurements show that observable gaps account for approximately 15% of the total measured thickness. It is reasonable to believe that there are even finer loose tissues within the corrosion layer. If this looseness contributes 5% to the measured thickness increase, then the increase in oxide layer thickness due to looseness is approximately 20%, which is the actual difference between the thickness values ​​obtained from the two measurement methods. Therefore, in this example, to obtain the apparent thickness of the corrosion layer using this method, the initial function needs to be further corrected using the thickness change caused by the looseness of the corrosion layer. That is, as mentioned earlier, a more accurate working curve is obtained by correcting the function relationship using a typical sample. After considering a 20% thickness increment, the corrected working curve yields results that closely match the directly observed thickness of the corrosion layer. This working curve can then be used to measure or evaluate the oxide layer thickness on samples or workpieces with similar conditions.

[0089] Regarding the specific implementation methods of this application, it should be noted that:

[0090] In the description of this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, or readable storage medium that comprises a list of elements includes not only those elements but also other elements not expressly listed that conform to the concept of this application, or elements inherent to such a process, method, apparatus, or readable storage medium. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of additional elements in the process, method, apparatus, or readable storage medium that includes said element.

[0091] In the description of this application, the use of terms such as "some embodiments," "optional embodiments," "example," "specific example," "optional example," or "optional embodiment," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application, but does not imply that these embodiments illustrate and describe all possible forms of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0092] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments; the above description should not be construed as a limitation of the present invention. Technical solutions between various embodiments can be combined with each other, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application. Although embodiments of the present application have been shown and described, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application. Those skilled in the art will understand that various other specific changes and combinations of embodiments based on the technical teachings disclosed in this application, without departing from the essence of the present application, are still within the scope of protection defined by the claims of the present invention and their equivalent technical solutions.

Claims

1. A method for measuring the thickness of a thin film on the surface of a crystalline material, characterized in that, Used for measuring crystalline materials, denoted as the test piece, including: Establish a physical model of the substrate and surface thin film of the crystalline material, and calculate the theoretical values ​​of the relative X-ray diffraction intensity of the crystalline material corresponding to surface thin films of different thicknesses; Using the ratio of diffraction peak intensity M between the surface film and the substrate, and the thickness d of the surface film as one of the horizontal and vertical axes, respectively, the corresponding data points are plotted, and the relationship between M and d is fitted and constructed. X-ray diffraction scanning was performed on the test piece to extract the intensity of the independent diffraction peaks of the substrate and the surface film, and the intensity of the independent diffraction peaks was corrected. Based on the corrected independent diffraction peak intensities of the substrate and the thin film, representative diffraction peaks are selected, and the ratio of the diffraction peak intensities of the surface thin film to those of the substrate is substituted into the aforementioned formula to calculate the thickness of the corresponding surface thin film.

2. The method for measuring the thickness of a thin film on the surface of a crystalline material according to claim 1, characterized in that, The specific steps involved in drawing the corresponding data points are: From the theoretical values ​​of relative diffraction intensity, select typical diffraction peaks of the surface film and the substrate, or the sum of the intensities of multiple diffraction peaks, and calculate the ratio of the relative diffraction intensity of the surface film and the substrate. List the thickness of the surface film and the corresponding ratio of the relative diffraction intensity to form data points. Plot the corresponding data points in the coordinate system with the ratio M of the diffraction peak intensity of the surface film and the substrate as the abscissa and the thickness d of the surface film as the ordinate.

3. The method for measuring the thickness of a thin film on the surface of a crystalline material according to claim 2, characterized in that, The specific method for fitting and constructing the relationship between M and d is as follows: based on each of the data points, the least squares method is used to fit the theoretical curve.

4. The method for measuring the thickness of a thin film on the surface of a crystalline material according to any one of claims 1-3, characterized in that, After constructing the relationship, if an observable defect appears in the surface film, the relationship is modified. During the modification, the actual measured value of the test piece is compared with the theoretical value, so that the curve corresponding to the relationship is close to the curve corresponding to the actual measured value.

5. The method for measuring the thickness of a thin film on the surface of a crystalline material according to claim 1, characterized in that, When performing X-ray diffraction scanning on the test piece, if the test piece has a preferred orientation, the number of independent diffraction peaks covering the substrate and surface film in the scanning range is greater than or equal to 3; if the test piece does not have a preferred orientation, the number of independent diffraction peaks covering the substrate and surface film in the scanning range is greater than or equal to 1.

6. The method for measuring the thickness of a thin film on the surface of a crystalline material according to claim 1, characterized in that, The extraction of independent diffraction peak intensities of the substrate and surface film includes: extracting the independent diffraction peak intensities of the substrate and surface film using software or calculation methods.

7. The method for measuring the thickness of a thin film on the surface of a crystalline material according to claim 6, characterized in that, When extracting the independent diffraction peak intensities of the substrate and the surface film: If software is used, the diffraction peak intensities of the substrate and the surface film are integrated, and the integrated intensity is used as the intensity of the independent diffraction peak. If a calculation method is used, the intensity of the independent diffraction peak is determined by multiplying the intensity value at the apex of the diffraction peak by the peak width at half the height of the diffraction peak.

8. The method for measuring the thickness of a thin film on the surface of a crystalline material according to claim 6, characterized in that, When correcting the intensity of independent diffraction peaks, the following formula is used: y i =a i x i / b Among them, y i To correct the intensity of the independent diffraction peak, x i Related to the initial intensity of the diffraction peak, the multiplicity factor, and the relative diffraction intensity factor, a i is a parameter related to the multiplicity factor, and b is a coefficient related to the relative diffraction intensity factor.

9. The method for measuring the thickness of a thin film on the surface of a crystalline material according to claim 2, characterized in that, The selection of representative diffraction peaks means that the selected diffraction peaks are consistent with the diffraction peaks selected when plotting the corresponding data points.

10. The method for measuring the thickness of a thin film on the surface of a crystalline material according to any one of claims 1-3 and 5-9, characterized in that, The physical model includes a two-layer structure of substrate and surface film, or a multi-layer structure including substrate and multiple surface films, or a multi-layer structure including substrate, hybrid layer and surface film; the surface film includes nitride film, oxide film, metal or non-metal film.

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