A high-precision spectral detection method for real-time detection of CVD diamond deposition

Abstract

The present invention proposes a high-precision spectral detection method for real-time detection of CVD diamond deposition, comprising the following steps: S1: fixing the optical fiber probe of the spectral diagnostic device to the quartz observation window of the CVD equipment, and adjusting the angle of the optical fiber probe to achieve high-precision positioning of the optical fiber probe at different radial positions of the deposition platform; S2: collecting background signals at different radial positions of the plasma and spectral signals at different radial positions of the plasma during the diamond deposition process in the CVD equipment; S3: identifying characteristic peaks in the spectral signals and using the intensity of the spectral characteristic peaks to detect and determine the stability of the CVD diamond deposition process; S4: using the characteristic values ​​of different ionic groups to detect and evaluate the effective deposition range and deposition quality of CVD diamond under this process. The detection method proposed by the present invention is convenient and fast, and can achieve high-precision detection of the stability and effective deposition area of ​​CVD diamond deposition during the deposition reaction.

Description

Technical Field

[0001] The present invention relates to the technical field of diamond detection, and in particular to a high-precision spectrum detection method for real-time detection of CVD diamonds. Background Art

[0002] Diamond has extremely excellent mechanical, thermal, optical and electrical properties, such as extremely high hardness, high thermal conductivity, wide optical transmission band, large bandgap and high carrier mobility. It has broad application prospects in important fields such as power electronics, aerospace, military and national defense. MPCVD has the advantages of no electrode contamination, high plasma density, stable discharge and wide deposition range. It is the first choice for preparing high-quality diamond self-supporting films. In the past few decades, there have been a lot of research on the preparation of diamond self-supporting films, but due to the limitations of chemical vapor deposition technology and equipment, high-grade diamond films have not been widely used. The preparation process of large-scale, high-grade diamond films is difficult and costly. In addition to overcoming growth process problems such as uniformity, integrity and internal defects, the distribution of plasma excited by the electric field inside the equipment is also crucial. This feature greatly increases the threshold for the preparation of large-scale, high-grade diamond films.

[0003] The microwave electric field and plasma distribution within the reaction chamber are uneven, and the radical concentration gradually decreases from the center of the plasma toward the edge. When the radical concentration is too low, high-quality diamond cannot form, indicating that the effective deposition range has been exceeded. Diamond film deposition typically takes dozens or even hundreds of hours. Regulating the deposition range and quality by inspecting the post-growth morphology and crystal quality often has a lag, resulting in long testing cycles and high costs. Furthermore, the MPCVD diamond deposition reaction is highly complex. Carbon-containing gases and hydrogen, under microwave action, form a complex plasma containing more than a dozen carbon-containing radicals. The radical types and their concentrations vary and continuously change with variations in gas type, pressure, and power. Because the reaction process is constantly changing and measurement errors due to ambient light and probe heating are difficult to avoid, optimizing the testing method to improve the accuracy of the test results is crucial. Spectral diagnostics can be used to monitor the effective deposition area during the deposition reaction to determine the stability of the deposition process. This allows for a wider effective deposition area and enables the production of high-quality, large-scale diamond films.

[0004] For example, the invention patent with application number 202010973478.8 provides a method for detecting the grade of diamond micropowder using Raman spectroscopy and its application in the detection of diamond micropowder grade. The method includes detecting the fluorescence intensity value and Raman spectrum intensity value of the diamond micropowder sample; then according to the formula The diamond powder grade is calculated. This method can accurately detect the grade of diamond powder, enabling quality control of diamond powder, and is particularly helpful for its effective use. This method is convenient and quick, with excellent application results. However, after the method is applied to diamond production, it cannot monitor the diamond during the production process. Summary of the Invention

[0005] In response to the technical problem that existing diamond detection cannot achieve real-time monitoring during the production process, the present invention proposes a high-precision spectral detection method for real-time detection of CVD diamond deposition stability and effective deposition area, which can achieve high-precision detection of CVD diamond deposition stability and effective deposition area during the deposition reaction process.

[0006] In order to achieve the above object, the technical solution of the present invention is implemented as follows: a high-precision spectral detection method for real-time detection of CVD diamond deposition comprises the following steps:

[0007] S1: Fix the optical fiber probe of the spectral diagnostic device on the quartz observation window of the CVD equipment, and adjust the angle of the optical fiber probe to achieve high-precision positioning of the optical fiber probe at different radial positions of the deposition table;

[0008] S2: Collect the background signals at different radial positions of the plasma and the spectral signals at different radial positions of the plasma during the diamond deposition process in the CVD equipment to obtain the background spectrum intensity S d and the measured spectral intensity S m ;

[0009] S3: Using the background spectrum and the measured spectrum to identify the characteristic peaks in the spectral signal, and using the intensity of the spectral characteristic peaks to detect and determine the stability of the CVD diamond deposition process;

[0010] S4: Using the characteristic values ​​of different ionic groups, the effective deposition range and deposition quality of CVD diamond under this process are tested and evaluated.

[0011] The spectral diagnostic device in step S1 includes a laser pointer, a fiber optic probe, a fiber optic spectrometer and a data processing system. The data processing system, the spectrometer and the fiber optic probe are connected in sequence. The laser pointer is connected to the data processing system. The fiber optic probe is fixed to the quartz observation window of the CVD device through a probe fixing device. The laser pointer is set at the top window of the CVD device.

[0012] The specific method of adjusting the angle of the optical fiber probe in step S1 to achieve high-precision positioning of the optical fiber probe at different radial positions of the deposition table is as follows: first adjust the laser pointer so that it is aligned with the center of the deposition molybdenum table, and then rotate the angle of the optical fiber probe so that the center point of the deposition table calibrated by the laser pointer, the quartz observation window and the optical fiber probe are located in the same straight line, thereby achieving high-precision positioning of the optical fiber probe.

[0013] The specific method of collecting background signals and spectral signals in step S2 is:

[0014] S21: Place a light shield between the quartz observation window and the optical fiber probe to collect background signals at different radial positions of the plasma to obtain background spectra;

[0015] S22: Remove the light shield between the quartz observation window and the optical fiber probe, collect spectral signals at different radial positions of the plasma during the diamond deposition process, and obtain a measured spectrum.

[0016] The shading sheet is made of double-sided matte black PET material.

[0017] During the diamond deposition in step S22, the ratio of CH4 / H2 is 4-8%, the reaction temperature in the CVD equipment is 800-1000°C, the gas pressure is 100-140 torr, and the power is 5-10kW.

[0018] The method for detecting the stability of the CVD diamond deposition process using the intensity of the spectral characteristic peak in step S3 is:

[0019] When CH4 is introduced into the CVD device, spectral data collection begins. When the time after CH4 is introduced t≤20min, measurement is performed every 2-4min; when the time after CH4 is introduced t>20min, measurement is performed every 1-2min, and the number of measurements n satisfies 10≤n≤20.

[0020] The method of using the background spectrum and the measured spectrum to identify the characteristic peaks in the spectral signal in step S3 is:

[0021] When using the data processing system to identify the characteristic peaks in the spectral data, H α The characteristic peak intensity S corresponding to the emission spectrum of the active group C As the eigenvalue, S C is the measured spectral intensity S m The intensity of the C2 characteristic peak S mC and background spectrum intensity S d The intensity of the C2 characteristic peak S dC The difference, that is, S C =S mC -S dC .

[0022] Step S3 is to determine the stability of the CVD diamond deposition process by using the experimental standard deviation s r (S c ) to evaluate the repeatability of the measurement results, the formula is as follows:

[0023]

[0024] Where S Ci is the measured value of each measurement, n is the number of measurements, is the arithmetic mean of n measurements, 10≤n≤20; when s r When (Sc) < 0.2, the data repeatability is good and meets the test requirements; when s r When (Sc)≥0.2, it is necessary to extend the reaction time and re-collect the spectral data, and re-collect the background spectrum before the spectral test.

[0025] The specific steps of step S4 for detecting and evaluating the effective deposition range and deposition quality of CVD diamond are as follows:

[0026] S41: First, the measured spectral intensity S collected by the spectrometer m and background spectral intensity S d Perform normalization processing,

[0027]

[0028] Where t is the integration time during the test, and ε is the calibration coefficient;

[0029] S42: Select H α The peak value I of the characteristic peak corresponding to the emission spectrum of the active group and the C2 active group H and I C As the characteristic value, the center point of the deposition table in the CVD equipment is used as the reference, and points are taken every 10 mm along the diameter direction for testing, which are recorded as 0, 1, 2, ... i, i+1 respectively;

[0030] S43: With H α Characteristic peak intensity of active group I H0 As the benchmark, when H α Characteristic peak intensity of active group I Hi with I H0 The ratio I Hi / I H0 ≥0.8, and H at the i+1th test point α Characteristic peak intensity of active group I Hi+1 with I H0 The ratio I Hi+1 / I H0 When <0.8, the effective deposition area S of CVD diamondq =(10×i) 2 ×3.14;

[0031] S44: The characteristic peak intensity of the C2 active group at the center of the plasma I C0 As the benchmark, when the i-th test point is I C0 The characteristic peak intensity I Ci >I C0 When the deposition rate V0 is compared with the deposition rate at the center of the plasma, the carbon-containing active particles have a higher concentration and chemical activity at the test point to promote diamond growth. The deposition rate V i >V0.

[0032] The technical solution provided by the present invention has the following advantages:

[0033] 1. To address the problems of dynamic changes in the reaction process, differences in ambient light, and probe heating that can distort test results when performing chemical group diagnosis using emission spectroscopy, the method of collecting spectral signals by defining sampling time and repeatability evaluation can effectively improve the accuracy of test results and avoid the increase in measurement errors caused by these factors.

[0034] 2. In view of the complex reaction types and multiple types of carbon-containing groups in the diamond vapor deposition process, the present invention establishes a correspondence between the characteristic emission lines of active groups and the effective deposition range of CVD diamond. This provides a scientific and effective method for detecting the effective deposition range under this process during the CVD reaction, greatly improving the timeliness of detection.

[0035] 3. The spectral diagnostic method performs real-time in-situ detection of changes in chemical group concentrations during the reaction process, which can reflect the true information of gas-phase species and chemical reactions during the deposition process. By measuring the repeatability of spectral characteristic values, it can effectively monitor the stability of the deposition process, which is more conducive to achieving stable deposition and growth of diamonds in production. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 Schematic diagram of the positioning system of the present invention;

[0038] Figure 2 This is the principle diagram of plasma emission spectrum measurement;

[0039] Figure 3 is the plasma emission spectrum of the reaction system;

[0040] Figure 4 H α The intensity of the C2 spectral line varies along the radial direction of the plasma;

[0041] Figure 5 These are SEM images of diamond growth morphology at positions P0, P2, P4, and P5. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0043] Example 1

[0044] like Figure 1 As shown, a high-precision spectral detection method for real-time detection of CVD diamond deposition stability and effective deposition area is provided. The specific method is as follows:

[0045] S1: Fix the optical fiber probe of the spectral diagnostic device on the quartz observation window of the CVD equipment, adjust the angle of the optical fiber probe, and achieve high-precision positioning of the optical fiber probe at different radial positions of the deposition table.

[0046] Specifically, the spectral diagnostic device includes a laser pointer, a fiber optic probe, a fiber optic spectrometer and a data processing system. The data processing system, the spectrometer and the fiber optic probe are connected in sequence, and the fiber optic probe is fixed to the quartz observation window through a probe fixture. The laser pointer is connected to the data processing system, and the laser pointer is set in the top window of the CVD equipment. The laser pointer is equipped with a position adjustment device. When in use, first adjust the laser pointer to align it with the center of the deposition molybdenum table, and then rotate the angle of the fiber optic probe so that the center point of the deposition table calibrated by the laser pointer, the quartz observation window and the fiber optic probe are on the same straight line, thereby achieving high-precision positioning of the fiber optic probe. The probe fixture is set on the quartz observation window of the CVD equipment, and the distance between the probe and the quartz observation window is 4-6mm.

[0047] The spectral diagnostic device is used to monitor the diamond deposition stability and effective deposition area in the CVD equipment in real time, effectively improving the accuracy of the test results.

[0048] S2: Collect background signals at different radial positions of the plasma and spectral signals at different radial positions of the plasma during CVD diamond deposition. The specific steps are:

[0049] S21: Place a light shield between the quartz observation window and the fiber optic probe to prevent the reaction light signal and ambient light in the CVD equipment cavity from entering the fiber optic probe, and collect background signals at different radial positions of the plasma.

[0050] When using a spectrometer to collect background signals at different radial locations in the plasma, a light shield should be placed between the quartz observation window and the fiber optic probe to prevent ambient light from being captured by the probe. To ensure effective light shielding, the light shield should preferably be made of double-sided matte black PET with a thickness of 3-5 mm.

[0051] S22: Remove the light shield between the quartz observation window and the optical fiber probe to collect spectral signals at different radial positions of the plasma during the diamond deposition process.

[0052] During CVD diamond deposition, the CH₄ / H₂ ratio is 4-8%, the reaction temperature is 800-1000°C, the pressure is 100-140 Torr, and the power is 5-10 kW. After removing the light shield, spectral signals are collected at different radial positions of the plasma during the CVD diamond deposition process.

[0053] S3: Identify the characteristic peaks in the spectral signal and use the intensity of the spectral characteristic peaks to determine the stability of the CVD diamond deposition process.

[0054] The method for monitoring the stability of the deposition process is as follows: spectrum data is collected starting from the time CH4 is introduced. When the time t after CH4 is introduced is ≤ 20 min, measurement is performed every 2-4 min; when the time t after CH4 is introduced is > 20 min, measurement is performed every 1-2 min, and the number of measurements n satisfies 10 ≤ n ≤ 20.

[0055] When using the data processing system to identify the characteristic peaks in the spectral data, H α The characteristic peak intensity S corresponding to the emission spectrum of the active group C As the eigenvalue, S C is the measured spectrum S m The intensity of the C2 characteristic peak S mC With the background spectrum S d The intensity of the C2 characteristic peak S dC The difference, that is, S C =S mC -S dC .

[0056] When judging the stability of the deposition process, the experimental standard deviation s is used. r (S) Evaluate the repeatability of the measurement results using the following formula:

[0057]

[0058] Where S Ci is the measured value of each measurement, n is the number of measurements, is the arithmetic mean of n measurements, 10≤n≤20. r When (Sc) < 0.2, the data repeatability is good and meets the test requirements; when s r When (Sc) ≥ 0.2, the background signal is distorted due to unstable internal reaction state or probe heating. It is necessary to extend the reaction time and re-collect the spectral data, and re-collect the background spectrum before the spectral test.

[0059] S4: Using the characteristic values ​​of different ionic groups, the effective deposition range and deposition quality of CVD diamond under this process are tested and evaluated.

[0060] First, the emission peak intensity values ​​collected by the spectrometer are normalized using the following formula:

[0061]

[0062] Among them, S m is the measured spectral intensity during the deposition process, S d is the background spectrum intensity, t is the integration time during the test, and ε is the calibration coefficient.

[0063] Select H α The peak value I of the characteristic peak corresponding to the emission spectrum of the active group and the C2 active group H and I C As a characteristic value, the C2 active group has multiple emission spectrum characteristic peaks, and the peak with the strongest peak is selected as the characteristic peak, and the strongest peak is the characteristic peak.

[0064] Taking the center point of the deposition platform as the reference, test points were taken at intervals of 10 mm along the diameter direction and recorded as 0, 1, 2, ...i, i+1 respectively.

[0065] H α Characteristic peak intensity of active group I H0 As the benchmark, when H α Characteristic peak intensity of active group I Hi with I H0 The ratio I Hi / I H0 ≥0.8, and H at the i+1th test point α Characteristic peak intensity of active group I Hi+1 with I H0 The ratio I Hi+1 / I H0 When <0.8, the effective deposition area S of CVD diamondq =(10×i) 2 ×3.14. (Unit: mm 2 )

[0066] The characteristic peak intensity of the C2 active group at the center of the plasma is I C0 As the benchmark, when the i-th test point is I C0 The characteristic peak intensity I Ci >I C0 When the deposition rate V0 is compared with the deposition rate at the center of the plasma, the carbon-containing active particles have a higher concentration and chemical activity at the test point to promote diamond growth. The deposition rate V i >V0.

[0067] In the field of CVD diamond preparation, this detection method uses the online real-time detection method of optical emission spectroscopy for quality detection, and the spectral detection results can be used to determine the effective deposition range. In vapor deposition preparation technology, compared with the conventional method of determining the effective deposition range by quality detection of deposited samples, optical emission spectroscopy has the advantages of being fast and low-cost.

[0068] Example 2

[0069] Under the deposition conditions of a CH4 / H2 ratio of 4%, a reaction temperature of 950°C, a gas pressure of 130 torr, and a power of 10 kW, a spectrometer was used to detect the deposition process stability, effective deposition range, and deposition quality during the CVD diamond deposition process.

[0070] Determination of the stability of the deposition process:

[0071] The optical fiber probe of the spectrometer was fixed on the quartz observation window of the CVD equipment, with a distance of 6 mm between the probe and the quartz observation window. The probe was adjusted to the center of the deposition platform using the positioning system, and this position was marked as P0. A 5 mm thick black matte PET light shielding sheet was placed between the quartz observation window and the optical fiber probe to shield the optical fiber probe and collect background signals. After removing the light shielding sheet, the spectrum signal at the center position was collected after CH4 gas was introduced. Within 20 minutes after CH4 was introduced, the signal was collected every 2 minutes. After more than 20 minutes, the signal was collected every 1 minute. A total of 20 signals were collected, and the obtained H α The difference S between the measured intensity of the characteristic peak and the background spectrum intensity H As shown in Table 1. After calculation, the standard deviation of 10 test results within 20 minutes after CH4 was introduced is s r (S)=139.881, does not meet s r <0.2 experimental requirements; standard deviation of 10 test results after CH4 is introduced for more than 20 minutes s r (S) = 0.169, satisfying sr The experimental requirement of <0.2 indicates that the reaction state inside the cavity tends to be stable after CH4 is introduced for more than 20 minutes, and there is no problem of probe heating causing background spectrum distortion, so there is no need to repeat the background spectrum test.

[0072] Table 1

[0073]

[0074] Effective deposition range detection:

[0075] Rotate the fiber optic probe angle A to align it with different positions (such as 0mm, 10mm, 20mm, 30mm, 40mm, and 50mm) from the plasma center. Figure 2 As shown, the distances from the plasma center are 0 mm, 10 mm, 20 mm, 30 mm, 40 mm, and 50 mm, respectively, marked as P0, P1 / P1', P2 / P2', P3 / P3', P4 / P4', and P5 / P5'), and the background signals and deposition process spectral signals at different positions are collected. Figure 2 In the figure, R1 is the distance from the optical fiber probe to the observation window, R2 is the distance from the observation window to the center of the plasma in the microwave resonant cavity, and R3 is the plasma radius for spectral signal collection.

[0076] The emission peak intensity values ​​collected by the spectrometer are normalized based on the background signal, the deposition process spectrum signal, the integration time and the calibration coefficient. The plasma spectrum data obtained by the full spectrum scan are as follows: Figure 3 As shown, there are mainly C2 groups at 563nm, 606nm, 612nm, and 619nm, and H at 656nm. α Spectral lines. The spectral peaks at 563nm and 656nm are respectively taken as C2 and H α The characteristic peaks of the active groups are plotted to draw the curve of the characteristic peak intensity at different radial positions of the plasma (P1', P2', P3', P4', P5', P0, P1, P2, P3, P4, P5). Figure 4 As shown, H at P4 α The characteristic peak intensity I H4 with I H0 The ratio I H4 / I H0 >0.8, but H at P5 α The characteristic peak intensity I H5 with I H0 The ratio I H5 / I H0 <0.8, indicating that the concentration of active groups at P5 cannot meet the concentration requirements for diamond deposition. After calculation, the effective deposition area S of CVD diamond at this time q=(10×4) 2 ×3.14=5024mm 2 .

[0077] like Figure 5 As shown, the diamonds at position P5 transform from large, fully grown grains to small, delayed-growth, and noticeable growth defects, with grain sizes no larger than 50μm. Diamonds at positions P0, P2, and P4 are mostly composed of hexahedral and octahedral grains. Due to competitive growth between the grains, a small number of incompletely grown fine grains are interspersed between the relatively large, fully grown grains. The relatively fully grown grains are approximately 100-200μm in size, while the incompletely grown grains are approximately 10-50μm in size.

[0078] By measuring the growth thickness of the diamond film, the growth rates of the diamond film at positions P0, P2, P4, and P5 were found to be 2.2μm / h, 2.8μm / h, 3.0μm / h, and 0.7μm / h, respectively. The change in growth rate corresponds well to the trend of change in the C2 spectral line intensity along the radial direction of the plasma.

[0079] Other structures and principles are the same as those in Example 1.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-precision spectral detection method for real-time detection of CVD diamond deposition, characterized in that: The following steps are involved: S1: Fix the optical fiber probe of the spectral diagnostic device on the quartz observation window of the CVD equipment, and adjust the angle of the optical fiber probe to achieve high-precision positioning of the optical fiber probe at different radial positions of the deposition table; S2: Collect the background signals at different radial positions of the plasma and the spectral signals at different radial positions of the plasma during the diamond deposition process in the CVD equipment to obtain the background spectrum intensity S d and the measured spectral intensity S m ; S3: Using the background spectrum and the measured spectrum to identify the characteristic peaks in the spectral signal, and using the intensity of the spectral characteristic peaks to detect and determine the stability of the CVD diamond deposition process; S4: Using the characteristic values ​​of different ionic groups, the effective deposition range and deposition quality of CVD diamond are tested and evaluated; The specific steps of step S4 for detecting and evaluating the effective deposition range and deposition quality of CVD diamond are as follows: S41: First, the measured spectral intensity S collected by the spectrometer m and background spectral intensity S d Perform normalization processing, Where t is the integration time during the test, and ε is the calibration coefficient; S42: Select H α The peak value I of the characteristic peak corresponding to the emission spectrum of the active group and the C2 active group H and I C As the characteristic value, the center point of the deposition table in the CVD equipment is used as the reference, and points are taken every 10 mm along the diameter direction for testing, which are recorded as 0, 1, 2, ... i, i+1 respectively; S43: With H α Characteristic peak intensity of active group I H0 As the benchmark, when H α Characteristic peak intensity of active group I Hi with I H0 The ratio I Hi / I H0 ≥0.8, and H at the i+1th test point α Characteristic peak intensity of active group I Hi+1 with I H0 The ratio I Hi+1 / I H0 When <0.8, the effective deposition area S of CVD diamond q =(10×i) 2 ×3.14; S44: The characteristic peak intensity of the C2 active group at the center of the plasma I C0 As the benchmark, when the i-th test point is I C0 The characteristic peak intensity I Ci >I C0 When the deposition rate V0 is compared with the deposition rate at the center of the plasma, the carbon-containing active particles have a higher concentration and chemical activity at the test point to promote diamond growth. The deposition rate V i >V0.

2. The high-precision spectral detection method for real-time detection of CVD diamond deposition according to claim 1, characterized in that: The spectral diagnostic device in step S1 includes a laser pointer, a fiber optic probe, a fiber optic spectrometer and a data processing system. The data processing system, the spectrometer and the fiber optic probe are connected in sequence. The laser pointer is connected to the data processing system. The fiber optic probe is fixed to the quartz observation window of the CVD device through a probe fixing device. The laser pointer is set at the top window of the CVD device.

3. The high-precision spectral detection method for real-time detection of CVD diamond deposition according to claim 2, characterized in that: The specific method of adjusting the angle of the optical fiber probe in step S1 to achieve high-precision positioning of the optical fiber probe at different radial positions of the deposition table is as follows: first adjust the laser pointer so that it is aligned with the center of the deposition molybdenum table, and then rotate the angle of the optical fiber probe so that the center point of the deposition table calibrated by the laser pointer, the quartz observation window and the optical fiber probe are located in the same straight line, thereby achieving high-precision positioning of the optical fiber probe.

4. The high-precision spectral detection method for real-time detection of CVD diamond deposition according to claim 2 or 3, characterized in that: The specific method of collecting background signals and spectral signals in step S2 is: S21: Place a light shield between the quartz observation window and the optical fiber probe to collect background signals at different radial positions of the plasma to obtain background spectra; S22: Remove the light shield between the quartz observation window and the optical fiber probe, collect spectral signals at different radial positions of the plasma during the diamond deposition process, and obtain a measured spectrum.

5. The high-precision spectral detection method for real-time detection of CVD diamond deposition according to claim 4, characterized in that: The shading sheet is made of double-sided matte black PET material.

6. The high-precision spectral detection method for real-time detection of CVD diamond deposition according to claim 5, characterized in that: During the diamond deposition in step S22, the ratio of CH4 / H2 is 4-8%, the reaction temperature in the CVD equipment is 800-1000°C, the gas pressure is 100-140 torr, and the power is 5-10kW.

7. The high-precision spectral detection method for real-time detection of CVD diamond deposition according to claim 6, characterized in that: The method for detecting the stability of the CVD diamond deposition process using the intensity of the spectral characteristic peak in step S3 is: When CH4 is introduced into the CVD device, spectral data collection begins. When the time after CH4 is introduced t≤20min, measurement is performed every 2-4min; when the time after CH4 is introduced t>20min, measurement is performed every 1-2min, and the number of measurements n satisfies 10≤n≤20.

8. The high-precision spectral detection method for real-time detection of CVD diamond deposition according to claim 7, characterized in that: The method of using the background spectrum and the measured spectrum to identify the characteristic peaks in the spectral signal in step S3 is: When using the data processing system to identify the characteristic peaks in the spectral data, H α The characteristic peak intensity S corresponding to the emission spectrum of the active group C As the eigenvalue, S C is the measured spectral intensity S m The intensity of the C2 characteristic peak S mC and background spectrum intensity S d The intensity of the C2 characteristic peak S dC The difference, that is, S C =S mC -S dC .

9. The high-precision spectral detection method for real-time detection of CVD diamond deposition according to claim 8, characterized in that: Step S3 is to determine the stability of the CVD diamond deposition process by using the experimental standard deviation s r (S c ) to evaluate the repeatability of the measurement results, the formula is as follows: Where S Ci is the measured value of each measurement, n is the number of measurements, is the arithmetic mean of n measurements, 10≤n≤20; when s r When (Sc) < 0.2, the data repeatability is good and meets the test requirements; when s r When (Sc)≥0.2, it is necessary to extend the reaction time and re-collect the spectral data, and re-collect the background spectrum before the spectral test.

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