Method, system and device for detecting iron doping concentration in iron-doped gallium nitride crystal

Abstract

The application discloses a kind of iron-doped gallium nitride crystal iron-doped concentration detection method, system and equipment.The method comprises: obtaining the image of iron-doped gallium nitride crystal, and correcting pre-processing to the image;Calculate the chromaticity-brightness coordinate of the image after correction pre-processing in CIExyY color space;Wherein, chromaticity-brightness coordinate represents the chromaticity information and brightness information of iron-doped gallium nitride crystal;According to the pre-set correlation model, the iron-doped concentration corresponding to chromaticity-brightness coordinate is calculated;Wherein, correlation model is the mapping model containing the mapping relationship between the representation chromaticity information and iron-doped concentration and the mapping relationship between the representation brightness information and iron-doped concentration.The present application can realize the rapid nondestructive testing of iron-doped concentration in iron-doped gallium nitride crystal, and it is simple and easy to operate, low in cost.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor material doping concentration detection, and more specifically, relates to a method, system and equipment for detecting iron doping concentration in iron-doped gallium nitride crystals. Background Technology

[0002] Iron-doped gallium nitride (Fe:GaN) is an important wide-bandgap semiconductor material. Compared to traditional unintentionally doped GaN, the superior properties of Fe:GaN make it an ideal substrate material for high-power microwave devices, deep ultraviolet optoelectronic devices, and sensors resistant to extreme environments.

[0003] Fe doping concentration is a key parameter of Fe:GaN materials, and it has a significant effect on the regulation of GaN's optoelectronic properties. For example, Fe doping concentration is located in the low concentration region (10). 16 cm -3 ~10 18 cm -3 When GaN is used for medium- and low-voltage photodetectors and blue LED substrates, Fe doping is located in the medium concentration region (10). 18 cm -3 ~5×10 19 cm -3 When GaN is used in high-power devices, Fe doping is suitable for high-concentration devices (5×10⁻⁶). 19 cm -3 ~10 20 cm -3 When Fe clusters induce lattice distortion, leading to a significant decrease in carrier mobility, the high defect density can be applied to special devices such as X-ray detectors and radiation-hardened devices; when the Fe doping concentration exceeds 10... 20 cm -3 In extreme cases, the material's structure may deteriorate significantly, leading to a comprehensive decline in electrical and optical properties. It may even trigger phase transitions or the precipitation of other phases, affecting the reliability and lifespan of the device. In summary, Fe doping concentration is a core indicator of Fe:GaN materials, and real-time, convenient, and non-destructive detection of Fe doping concentration is of great significance in its material preparation and related device manufacturing processes.

[0004] Doping concentration detection is a fundamental characterization and analysis method for semiconductor materials, and there are many related techniques. These include secondary ion mass spectrometry, Rutherford backscattering spectroscopy, X-ray photoelectron spectroscopy, photoluminescence spectroscopy, Hall effect testing, inductively coupled plasma mass spectrometry, and electrochemical capacitance-voltage method. However, all of these doping concentration detection techniques require expensive, specialized, and high-end equipment, have high operational and analytical barriers, and some techniques cannot be performed non-destructively. Summary of the Invention

[0005] The main objective of this invention is to provide a method, system, and device for detecting the iron doping concentration in iron-doped gallium nitride crystals, so as to overcome the shortcomings of the prior art.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] The first aspect of this invention provides a method for detecting the iron doping concentration in an iron-doped gallium nitride crystal, comprising: acquiring an image of the iron-doped gallium nitride crystal; performing correction preprocessing on the image; calculating the chromaticity-luminance coordinates of the corrected preprocessed image in the CIExyY color space; wherein the chromaticity-luminance coordinates represent the chromaticity information and luminance information of the iron-doped gallium nitride crystal; and calculating the iron doping concentration corresponding to the chromaticity-luminance coordinates according to a preset correlation model; wherein the correlation model is a mapping model that includes a mapping relationship representing the mapping relationship between chromaticity information and iron doping concentration and a mapping relationship representing the mapping relationship between luminance information and iron doping concentration.

[0008] Preferably, the process of establishing the correlation model includes: preparing multiple gallium nitride crystal samples with different iron doping concentrations N; acquiring sample images of each gallium nitride crystal sample and performing correction preprocessing on each sample image; calculating the coordinates (x, y, Y) of the corrected sample image in the CIExyY color space; where x represents red primary color information, y represents green primary color information, and Y represents brightness information; and establishing mapping relationships between x and N, y and N, and Y and N based on the multiple sets of corresponding N and (x, y, Y) obtained.

[0009] Preferably, the mapping relationship between x and N is as follows:

[0010] ;

[0011] And / or, the mapping relationship between y and N is:

[0012] hour:

[0013] ;

[0014] hour:

[0015] ;

[0016] And / or, the mapping relationship between Y and N is:

[0017] ;

[0018] in, , , , , , , , , , , , , , , , , These are the parameters obtained from the fitting.

[0019] Preferably, for iron doping concentrations of 10... 16 cm -3 ~10 20 cm -3 The method further includes: calculating 10 iron-doped gallium nitride crystals within the range of the correlation model. 16 cm -3 ~10 20 cm -3 Chromaticity-luminance coordinates corresponding to multiple different iron doping concentrations within a range are obtained, and corresponding color blocks are prepared based on the obtained chromaticity-luminance coordinates; a color scale colorimetric card is designed based on the prepared color blocks; the color scale closest to the chromaticity and luminance of the iron-doped gallium nitride crystal is selected from the color scale colorimetric card, and the iron doping concentration corresponding to this color scale is the iron doping concentration of the iron-doped gallium nitride crystal.

[0020] Preferably, a color scale color chart is designed based on the multiple color blocks obtained, specifically including: arranging the corresponding color blocks sequentially according to the increasing or decreasing trend of iron doping concentration to obtain a discrete color scale color chart; or, based on the multiple color blocks obtained, using interpolation to generate continuous color levels and corresponding iron doping concentrations to prepare a continuous gradient color scale color chart.

[0021] Preferably, calculating the chromaticity-luminance coordinates of the pre-processed image in the CIExyY color space specifically includes: calculating the RGB values ​​of the gallium nitride crystal in the pre-processed image; performing normalization and gamma correction on the RGB values ​​sequentially to obtain standard sRGB values; converting the standard sRGB values ​​into CIE-XYZ chromaticity coordinates in the CIE-XYZ color space; and converting the CIE-XYZ chromaticity coordinates into chromaticity-luminance coordinates in the CIExyY color space.

[0022] Preferably, calculating the RGB value of the gallium nitride crystal in the image after correction and preprocessing specifically includes: uniformly selecting multiple sampling points along the diagonal within the effective region surrounding the center of the iron-doped gallium nitride crystal in the image after correction and preprocessing, and taking the average of the RGB values ​​of the selected multiple sampling points as the RGB value of the iron-doped gallium nitride crystal.

[0023] Preferably, the method can also be used to detect the iron doping concentration in iron-doped gallium nitride materials, and the method further includes preparing iron-doped gallium nitride crystals before acquiring the image.

[0024] A second aspect of the present invention provides a system for detecting the iron doping concentration in an iron-doped gallium nitride crystal, comprising: a colorimetric chart, wherein each color level of the colorimetric chart is labeled with the iron doping concentration in the gallium nitride crystal, and the labeling principle is consistent with the correlation model used in the method for detecting the iron doping concentration in the iron-doped gallium nitride crystal; and a detector for selecting from the colorimetric chart the color level that is closest to the chromaticity and brightness of the iron-doped gallium nitride crystal, wherein the iron doping concentration corresponding to the color level is the iron doping concentration of the iron-doped gallium nitride crystal.

[0025] A third aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for detecting iron doping concentration in an iron-doped gallium nitride crystal as described above.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] (1) This invention provides a method, system, and device for detecting the iron doping concentration in iron-doped gallium nitride crystals. It discovers that different Fe doping concentrations in Fe:GaN crystals lead to visually perceptible color variations. Based on this discovery, a pre-defined correlation model is designed to characterize the mapping relationship between color-brightness information and iron doping concentration. When subsequently detecting the Fe doping concentration in Fe:GaN crystals, only the color-brightness information of the Fe:GaN crystal needs to be detected, thus achieving rapid and non-destructive detection of the Fe doping concentration in Fe:GaN crystals. The method is simple to operate and low in cost. It can even detect the Fe doping concentration with the naked eye.

[0028] (2) The present invention designs a color scale colorimetric card. The color scale colorimetric card standard has the Fe doping concentration of Fe:GaN crystal corresponding to each color scale, so that ordinary technicians in the preparation of Fe:GaN materials and the production of related devices can quickly carry out Fe doping concentration detection without the need for precision instruments, thereby improving production yield, reducing costs, and promoting the large-scale application and development of Fe:GaN. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a flowchart of a method for detecting iron doping concentration in an iron-doped gallium nitride crystal, provided in an embodiment of the present invention.

[0031] Figure 2 These are photographs of GaN crystals with different Fe doping concentrations under D65 standard light source illumination.

[0032] Figure 3 This is a photograph of Fe:GaN and a 24-color classic test card placed simultaneously on a neutral gray card.

[0033] Figure 4 The correlation function between the Fe:GaN chromaticity coordinate x and the Fe doping concentration is fitted.

[0034] Figure 5 The correlation function between the Fe:GaN chromaticity coordinate y and the Fe doping concentration is fitted.

[0035] Figure 6 The correlation function between the brightness information component Y of Fe:GaN and the Fe doping concentration is fitted.

[0036] Figure 7 This is a discrete colorimetric chart provided in an embodiment of the present invention.

[0037] Figure 8 A continuous gradient color chart provided for embodiments of the present invention.

[0038] Figure 9 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0039] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0040] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0041] Furthermore, in the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "horizontal," "vertical," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0042] In the description of this specification, the references to terms such as "an embodiment," "a particular embodiment," or "the embodiment" indicate 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 the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] Figure 1 For a flowchart of the method for detecting iron doping concentration in an iron-doped gallium nitride crystal provided in an embodiment of the present invention, please refer to [link / reference]. Figure 1 The detection method includes operations S100-S300.

[0044] Operate S100 to acquire an image of an iron-doped gallium nitride crystal, and perform correction preprocessing on the image.

[0045] Operation S200 calculates the chromaticity-luminance coordinates of the pre-processed image in the CIExyY color space; where the chromaticity-luminance coordinates represent the chromaticity and luminance information of the iron-doped gallium nitride crystal.

[0046] Operate S300 to calculate the iron doping concentration corresponding to the chromaticity-luminance coordinates based on the preset correlation model; wherein, the correlation model is a mapping model that includes the mapping relationship between chromaticity information and iron doping concentration and the mapping relationship between luminance information and iron doping concentration.

[0047] The iron doping concentration obtained in operation S300 is the iron doping concentration in the iron-doped gallium nitride crystal.

[0048] In a preferred embodiment, the process of establishing an association model is included before operation S100, specifically including the following operations SA1-SA4.

[0049] Using SA1, multiple gallium nitride crystal samples with different iron doping concentrations (N) were prepared.

[0050] Use SA2 to acquire sample images of each gallium nitride crystal sample, and perform correction preprocessing on each sample image.

[0051] Operation SA3 calculates the coordinates (x, y, Y) of the pre-processed sample image in the CIExyY color space; where x represents the red primary color information, y represents the green primary color information, and Y represents the brightness information.

[0052] Operation SA4 establishes the mapping relationships between x and N, y and N, and Y and N respectively, based on the multiple sets of corresponding N and (x, y, Y) obtained.

[0053] Preferably, the mapping relationship between x and N is as follows:

[0054] ;

[0055] Preferably, the mapping relationship between y and N is as follows:

[0056] hour:

[0057] ;

[0058] hour:

[0059] ;

[0060] Preferably, the mapping relationship between Y and N is as follows:

[0061] ;

[0062] in, , , , , , , , , , , , , , , , , These are the parameters obtained from the fitting.

[0063] In this invention, the above-mentioned association model can be established, for example, in the following manner.

[0064] Method 1: A deep learning-based neural network model is used to establish the aforementioned correlation model. Specifically, a large amount of sample data is collected in advance, with each set of sample data representing a corresponding N and (x, y, Y). This sample data is used to train the neural network model, thereby establishing the aforementioned correlation model. For any iron-doped gallium nitride crystal with an unknown iron doping concentration, an image of the iron-doped gallium nitride crystal is acquired. The image undergoes correction preprocessing, and the chromaticity-luminance coordinates of the corrected image in the CIExyY color space are calculated. These chromaticity-luminance coordinates are then input into the optimized neural network model to obtain the iron doping concentration of the gallium nitride crystal. The neural network model trained in this method only needs to input the chromaticity-luminance coordinates of the gallium nitride crystal into the model to automatically output the accurate iron doping concentration. Verification shows that compared to existing mature, highly accurate, and costly detection methods (this invention uses secondary ion mass spectrometry for comparison and verification), the detection accuracy error of this method is no greater than 1.2%.

[0065] Method 2: Based on the principle of nonlinear curve fitting, a polynomial fitting method is used to establish the above-mentioned correlation model. Specifically, multiple sets of corresponding N and (x, y, Y) are pre-collected, and the above-mentioned correlation model is obtained by fitting the collected data. For any iron-doped gallium nitride crystal with unknown iron doping concentration, an image of the iron-doped gallium nitride crystal is acquired, the image is pre-processed for correction, and the chromaticity-luminance coordinates of the pre-processed image in the CIExyY color space are calculated. Substituting these chromaticity-luminance coordinates into the above-mentioned correlation model, the iron doping concentration can be obtained. In this embodiment, 30 sets of corresponding N and (x, y, Y) are collected to fit the above-mentioned correlation model. After verification, compared with existing mature, highly accurate, and costly detection methods (the results measured by secondary ion mass spectrometry are used for comparison and verification in this invention), the detection accuracy error of this method is no greater than 2.1%. It should be noted that the more sets of corresponding N and (x, y, Y) that are collected in advance, the more accurate the fitted correlation model will be. When more sets of corresponding N and (x, y, Y) are collected, the above error will be further reduced.

[0066] In a preferred embodiment, for iron doping concentrations of 10 16 cm -3 ~10 20 cm -3 For iron-doped gallium nitride crystals within the specified range, the method includes the following operations S100'-S300'. Performing operations S100'-S300' can also obtain the iron doping concentration of the iron-doped gallium nitride crystal.

[0067] Operation S100' calculates 10 based on the correlation model. 16 cm -3 ~1020 cm -3 Chromaticity-luminance coordinates corresponding to multiple different iron doping concentrations within a range were determined, and corresponding color patches were prepared based on the obtained chromaticity-luminance coordinates.

[0068] Operate S200' to design a color scale comparison chart based on the multiple color patches obtained.

[0069] Operate S300' to select the color level that is closest to the color luminance of the iron-doped gallium nitride crystal from the color scale color chart. The iron doping concentration corresponding to this color level is the iron doping concentration of the iron-doped gallium nitride crystal.

[0070] In a preferred embodiment, operation S200' specifically includes: arranging the corresponding color blocks sequentially according to the increasing or decreasing trend of iron doping concentration to obtain a discrete colorimetric card. The colorimetric card is a discrete colorimetric card.

[0071] In another preferred embodiment, operation S200' specifically includes: generating continuous color levels and corresponding iron doping concentrations based on the multiple color patches obtained through interpolation, so as to prepare a continuous gradient colorimetric card. The colorimetric card is a continuous gradient colorimetric card.

[0072] Common Fe doping concentration windows are concentrated around 10. 16 cm -3 ~10 20 cm -3 Compared to unintentionally doped GaN crystals, Fe:GaN crystals within this Fe doping concentration range exhibit a pale orange-yellow color easily visible to the naked eye, with the color deepening continuously as the concentration increases. According to the relationship curve between the human eye's hue resolution threshold and wavelength, the human eye has the strongest hue resolution in the 560nm~600nm orange-yellow band, reaching 0.8nm~1.2nm. The pale orange-yellow color of Fe:GaN crystals falls precisely near the wavelength of strongest hue resolution for the human eye, providing a theoretical basis for naked-eye colorimetric Fe doping concentration detection, and also making the construction of the Fe:GaN colorimetry-doping concentration correlation model a feasible application prospect. This colorimetric card can be applied to production lines, allowing production line operators to initially screen products with concentrations that clearly do not meet the requirements. Figure 2 Taking the product shown as an example, the production line is for producing crystals in the second row and first column (Fe doping concentration 6.2 × 10⁻⁶). 18 cm -3 For example, when the color of a certain product produced is like... Figure 2 If the crystal is shown in the first row and first column or the fourth row and fourth column, the operator can determine the product is defective by naked-eye colorimetry, and thus select it to improve the production yield.

[0073] In a preferred embodiment, operation S200 specifically includes the following sub-operations S210-S240.

[0074] Sub-operation S210 calculates the RGB values ​​of the gallium nitride crystal in the image after correction and preprocessing.

[0075] Preferably, within the effective region surrounding the center of the iron-doped gallium nitride crystal in the image after correction and preprocessing, multiple sampling points are uniformly selected along the diagonal, and the average of the RGB values ​​of the selected multiple sampling points is taken as the RGB value of the iron-doped gallium nitride crystal.

[0076] Sub-operation S220 performs normalization and gamma correction on the RGB values ​​sequentially to obtain standard sRGB values.

[0077] Sub-operation S230 converts standard sRGB values ​​into CIE-XYZ chromaticity coordinates in the CIE-XYZ color space.

[0078] Sub-operation S240 converts the CIE-XYZ chromaticity coordinates to chromaticity-luminance coordinates in the CIExyY color space.

[0079] The method provided by this invention can also be used to detect the iron doping concentration in iron-doped gallium nitride (GaN) materials. When used to detect the iron doping concentration in GaN materials, the method further includes preparing an iron-doped GaN crystal before performing operation 100. The iron doping concentration in the iron-doped GaN crystal is the iron doping concentration in the iron-doped GaN material.

[0080] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0081] Taking the preparation of a colorimetric chart for detecting the Fe doping concentration in Fe:GaN crystals as an example, combined with... Figures 2-8 The present invention further explains the method for detecting iron doping concentration in iron-doped gallium nitride crystals.

[0082] Step 1: Prepare and process a series of high-quality Fe:GaN crystals.

[0083] A high-quality GaN buffer layer film of 2 μm was grown on a 2-inch sapphire substrate using metal-organic vapor phase epitaxy (MOE) at a growth rate of approximately 4 μm / h. Using this high-purity GaN buffer layer as a seed substrate, high-quality millimeter-scale (above 1 mm) GaN films were rapidly grown using hydride vapor phase epitaxy at a growth rate of approximately 150 μm / h. FeCl2 gas, generated from Fe and HCl at 850°C, was used as the dopant source and transported by a mixed N2 and H2 carrier gas. The Fe doping concentration was controlled by the HCl gas flow rate.

[0084] The Fe:GaN layer was separated from the sapphire substrate using a laser lift-off system, the oxide layer was removed by etching, and the sample to be tested was obtained with dimensions of 10mm×5mm×1mm by processes such as grinding, cleaving, laser cutting, and double-sided grinding and polishing.

[0085] Macroscopic morphology, crystal quality, and doping concentration were observed, analyzed, and verified using a microscope, X-ray diffractometer, and secondary ion mass spectrometer, respectively. The screening error density was less than 10. 4 cm -2 And (0002) and Samples to be tested that meet the quality standards are those with a half-peak width of less than 35 arcseconds and 30 arcseconds respectively in the rocking curve of X-ray double crystal diffraction.

[0086] To facilitate the explanation of the specific implementation process of the iron doping concentration detection method in iron-doped gallium nitride crystals, this example prepares eight sets of Fe:GaN samples. The example uses the pre-collection of eight corresponding N and (x, y, Y) sets to fit the aforementioned correlation model. The eight sets of prepared Fe:GaN samples are shown below. Figure 2 As shown. It should be noted that the selection of 8 Fe:GaN samples in this example is solely for illustrating the calculation process and is not the only possible approach. See also... Figure 2 From left to right, the four samples in the first row (labeled as Sample 1, Sample 2, Sample 3, and Sample 4) have Fe doping concentrations of 0, 1×10⁻⁶, and 1×10⁻⁶, respectively. 17 cm -3 1×10 18 cm -3 5×10 18 cm -3 The GaN samples, the four samples in the second row (labeled as sample 5, sample 6, sample 7, and sample 8), have an Fe doping concentration of 6.2 × 10⁻⁶. 18 cm -3 1×10 19 cm -3 3×10 19 cm -3 5×10 19 cm -3 GaN samples.

[0087] Step 2: Image acquisition and preprocessing of Fe:GaN crystal.

[0088] Illumination was performed using a LE009 reflective surface light source in a standard optical imaging laboratory. Each Fe:GaN crystal was placed sequentially on an 18% neutral gray card along with a 24-color classic test card, centered horizontally and aligned accordingly. Figure 3 As shown. After the image stabilizes, three sample images are captured consecutively at a resolution of 29 megapixels (6576×4384). The captured images are then calibrated and adjusted for white balance, exposure, contrast, and color.

[0089] Step 3: Image color space conversion.

[0090] For each preprocessed image, RGB values ​​of the GaN sample to be tested were acquired. Specifically, six sampling points (denoted as RGB1~RGB6) were evenly selected along the diagonal within an 80% effective region surrounding the sample center. The arithmetic mean of these sampling points was taken as the RGB value of the sample. avg The RGB values ​​of Fe:GaN with different doping concentrations are as follows.

[0091] Sample 1: Fe doping concentration 0, RGB values ​​(210.3, 204.7, 207.5).

[0092] Sample 2: Fe doping concentration 1×10 17 cm -3 RGB values ​​(200.8, 187.2, 174.0).

[0093] Sample 3: Fe doping concentration 1×10 18 cm -3 RGB values ​​(215.8, 193.5, 160.5).

[0094] Sample 4: Fe doping concentration 5×10 18 cm -3 RGB values ​​(219.7, 193.0, 136.8).

[0095] Sample 5: Fe doping concentration 6.2 × 10⁻⁶ 18 cm -3 RGB values ​​(210.2, 181.2, 107.5).

[0096] Sample 6: Fe doping concentration 1×10 19 cm -3 RGB values ​​(217.3, 185.7, 103.8).

[0097] Sample 7: Fe doping concentration 3×1019 cm -3 RGB values ​​(199.5, 115.7, 44.2).

[0098] Sample 8: Fe doping concentration 5×10 19 cm -3 RGB values ​​(181.2, 90.5, 50.8).

[0099] The RGB values ​​of each GaN sample were normalized and gamma-corrected to obtain standard sRGB values. Using the transformation matrix between CIE-XYZ chromaticity coordinates and standard sRGB values, the 1931 CIE-XYZ chromaticity coordinates of each GaN sample were obtained:

[0100] ;

[0101] The XYZ coordinates of Fe:GaN samples with different doping concentrations were calculated as follows.

[0102] Sample 1: Fe doping concentration 0, XYZ coordinates (60.62, 61.81, 51.63).

[0103] Sample 2: Fe doping concentration 1×10 17 cm -3 XYZ coordinates (50.67, 51.25, 35.89).

[0104] Sample 3: Fe doping concentration 1×10 18 cm -3 XYZ coordinates (55.62, 55.86, 31.45).

[0105] Sample 4: Fe doping concentration 5×10 18 cm -3 XYZ coordinates (55.23, 55.63, 24.00).

[0106] Sample 5: Fe doping concentration 6.2 × 10⁻⁶ 18 cm -3 XYZ coordinates (47.94, 47.75, 15.72).

[0107] Sample 6: Fe doping concentration 1×10 19 cm -3 XYZ coordinates (50.52, 49.91, 15.62).

[0108] Sample 7: Fe doping concentration 3×10 19 cm -3 XYZ coordinates (31.50, 25.07, 4.15).

[0109] Sample 8: Fe doping concentration 5×10 19 cm -3 XYZ coordinates (24.06, 17.53, 3.93).

[0110] Normalize X, Y, and Z, and denote the corresponding values ​​as x, y, and z, respectively:

[0111] ;

[0112] ;

[0113] ;

[0114] The coordinates (x, y, Y) containing chromaticity and luminance information of Fe:GaN with different doping concentrations are obtained as follows.

[0115] Sample 1: Fe doping concentration 0, xyY coordinates (0.348, 0.355, 61.81).

[0116] Sample 2: Fe doping concentration 1×10 17 cm -3 The xyY coordinates are (0.368, 0.372, 51.25).

[0117] Sample 3: Fe doping concentration 1×10 18 cm -3 The xyY coordinates are (0.390, 0.391, 55.86).

[0118] Sample 4: Fe doping concentration 5×10 18 cm -3 The xyY coordinates are (0.409, 0.412, 55.63).

[0119] Sample 5: Fe doping concentration 6.2 × 10⁻⁶ 18 cm -3 The xyY coordinates are (0.430, 0.428, 47.75).

[0120] Sample 6: Fe doping concentration 1×10 19 cm -3 The xyY coordinates are (0.435, 0.430, 49.91).

[0121] Sample 7: Fe doping concentration 3×10 19 cm -3 The xyY coordinates are (0.519, 0.413, 25.07).

[0122] Sample 8: Fe doping concentration 5×10 19 cm-3 The xyY coordinates are (0.529, 0.386, 17.53).

[0123] Step 4: Correlation between chromaticity and doping concentration N and model construction.

[0124] Based on the principle of nonlinear curve fitting, a functional expression of the chromaticity coordinate x as a function of the doping concentration N is fitted, and the correlation square R is used as a basis. 2 A simplified chi-square statistic is used to evaluate the goodness of fit. The fitting results are as follows: Figure 4 As shown, the expression is as follows:

[0125] ;

[0126] The fitting parameters obtained by fitting the 8 sets of corresponding N and (x, y, Y) are as follows: , , , R 2 R is 0.9616. 2 It can reflect the quality of the fit.

[0127] Based on the principle of nonlinear curve fitting, a functional expression of the chromaticity coordinate y as a function of the doping concentration N is fitted, and the correlation square R is used as a basis. 2 A simplified chi-square statistic is used to evaluate the goodness of fit. The fitting results are as follows: Figure 5 As shown, the expression is as follows:

[0128] hour:

[0129] ;

[0130] hour:

[0131] ;

[0132] The fitting parameters obtained by fitting the 8 sets of corresponding N and (x, y, Y) are as follows: , , , , , , , , , , , R 2 R is 0.95858. 2 It can reflect the quality of the fit.

[0133] Based on the principle of nonlinear curve fitting, a functional expression of the brightness information component Y as a function of the doping concentration N is fitted, and the correlation square R is used as a basis. 2 A simplified chi-square statistic is used to evaluate the goodness of fit. The fitting results are as follows: Figure 6 As shown, the expression is as follows:

[0134] ;

[0135] The fitting parameters obtained by fitting the 8 sets of corresponding N and (x, y, Y) are as follows: , , R 2 R is 0.91357. 2 It can reflect the quality of the fit.

[0136] After verification, combined with the corresponding obtained R, 2 The data shows that the detection accuracy error of the association model obtained by fitting 8 sets of corresponding N and (x, y, Y) is no greater than 8%. Correspondingly, the detection accuracy error of the association model obtained by fitting more sets of corresponding N and (x, y, Y) will be further reduced. For example, the detection accuracy error has been reduced to 2.1% when there are 30 sets.

[0137] A quantitative correlation expression for the chromaticity and brightness information coordinates (x, y, Y) of Fe:GaN crystal and the Fe doping concentration N was obtained, and a bidirectional prediction model for the chromaticity and brightness information coordinates and the Fe doping concentration N was constructed, namely the correlation model.

[0138] Step 5: Preparation of a colorimetric card for naked-eye detection of Fe:GaN crystal doping concentration.

[0139] Using the quantitative correlation expression between the chromaticity and brightness information coordinates (x, y, Y) of Fe:GaN crystal and the Fe doping concentration N, the Fe doping concentrations of Fe:GaN crystals at 0 and 1×10⁻⁶ can be inversely deduced. 17 cm -3 1×10 18 cm -3 5×10 18 cm -3 6.2×10 18 cm -3 1×10 19 cm -3 3×10 19 cm -3 5×10 19 cm -3The eight chromaticity and luminance coordinates are used to draw eight corresponding color blocks. These color blocks of equal size are arranged in ascending order of doping concentration, and the corresponding doping concentration values ​​are labeled below each color block to obtain a discrete colorimetric chart, such as... Figure 7 As shown.

[0140] Alternatively, select the Fe doping concentration range [0, 5 × 10⁻⁶]. 19 cm -3 Using the quantitative correlation expression between the chromaticity-luminance information coordinates (x, y, Y) of Fe:GaN crystal and the Fe doping concentration N, the chromaticity and luminance information coordinates corresponding to the upper and lower limits of the doping concentration range are inversely derived. A continuous color scale is generated using interpolation, and 0, 5×10 are sequentially labeled along the horizontal direction. 16 cm -3 1×10 17 cm -3 5×10 17 cm -3 1×10 18 cm -3 1×10 19 cm -3 5×10 19 cm -3 Key doping concentration values ​​are used to obtain a continuous gradient colorimetric chart, such as... Figure 8 As shown.

[0141] Step 6: Use a colorimetric card to detect the Fe doping concentration.

[0142] Place the self-supporting Fe:GaN crystal to be tested and the colorimetric card under the same lighting environment; compare the colorimetric brightness with the naked eye, select the color level that is closest to the colorimetric card, and read the Fe doping concentration value marked on the corresponding color card, which is the Fe doping concentration of the Fe:GaN crystal to be tested.

[0143] This example demonstrates the preparation of a series of high-quality Fe:GaN crystals with varying Fe doping concentrations. Images were acquired under a standard light source and converted into CIE-xyY chromaticity coordinates. A quantitative correlation model between chromaticity parameters and doping concentration was established using nonlinear fitting, leading to the creation of discrete or continuous colorimetric charts. Subsequent Fe doping concentration detection leverages the significant variation in Fe:GaN crystal chromaticity with doping concentration and the high resolution of the human eye in the corresponding wavelength bands, enabling rapid, non-destructive testing without the need for sophisticated instruments. The process is simple, cost-effective, and readily applicable to ordinary employees in Fe:GaN material preparation and device manufacturing, allowing for real-time and convenient assessment of doping concentration, improving production yield, and promoting its large-scale application in high-power microwave devices, deep-ultraviolet optoelectronic devices, and other fields.

[0144] Compared to the method of using a colorimetric card to detect the Fe doping concentration of Fe:GaN crystals provided in the above example, another implementation method is to use machine learning or other solution methods to solve the correlation model and obtain more accurate Fe doping concentration detection results. This can meet more precise detection requirements and also does not require precision instruments, making it simple to operate and low in cost.

[0145] Based on the same inventive concept, and corresponding to any of the above-described embodiments, this invention also provides a system for detecting the iron doping concentration in iron-doped gallium nitride (GaN) crystals, including a colorimetric chart and a detector. Each color level on the colorimetric chart is labeled with the iron doping concentration in the GaN crystal, and the labeling principle is consistent with the correlation model used in the aforementioned method for detecting the iron doping concentration in GaN crystals. The detector is used to select the color level from the colorimetric chart that is closest to the chromaticity and brightness of the GaN crystal; the iron doping concentration corresponding to this color level is the iron doping concentration of the GaN crystal.

[0146] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the method for detecting iron doping concentration in iron-doped gallium nitride crystals as described in any of the above embodiments.

[0147] Figure 9 This embodiment illustrates a more specific hardware structure of an electronic device, which may include a processor 910, a memory 920, an input / output interface 930, a communication interface 940, and a bus 950. The processor 910, memory 920, input / output interface 930, and communication interface 940 are interconnected internally via the bus 950.

[0148] The processor 910 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0149] The memory 920 can be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 920 can store the operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program code is stored in the memory 920 and is called and executed by the processor 910.

[0150] The input / output interface 930 is used to connect input / output modules to enable information input and output. Input / output modules can be configured as components within the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Input devices may include keyboards, mice, touchscreens, microphones, various sensors, etc., while output devices may include displays, speakers, vibrators, indicator lights, etc.

[0151] The communication interface 940 is used to connect the communication module (not shown in the figure) to enable communication between this device and other devices. The communication module can communicate via wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0152] Bus 950 includes a pathway for transmitting information between various components of the device, such as processor 910, memory 920, input / output interface 930, and communication interface 940.

[0153] It should be noted that although the above-described device only shows the processor 910, memory 920, input / output interface 930, communication interface 940, and bus 950, in specific implementations, the device may also include other components necessary for normal operation. Furthermore, those skilled in the art will understand that the above-described device may only include the components necessary for implementing the embodiments of this specification, and not necessarily all the components shown in the figures.

[0154] The electronic device described in the above embodiments is used to implement the iron doping concentration detection method in the iron-doped gallium nitride crystal in any of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0155] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for detecting the iron doping concentration in an iron-doped gallium nitride crystal, characterized in that, The method comprises the following steps: obtaining an image of the iron-doped gallium nitride crystal, and performing correction preprocessing on the image; calculating chrominance-brightness coordinates of the image after the correction preprocessing in a CIExyY color space; wherein the chrominance-brightness coordinates represent chrominance information and brightness information of the iron-doped gallium nitride crystal; calculating an iron-doped concentration corresponding to the chrominance-brightness coordinates according to a preset correlation model; wherein the correlation model is a mapping model containing a mapping relationship between the chrominance information and the iron-doped concentration and a mapping relationship between the brightness information and the iron-doped concentration; the process of establishing the correlation model comprises: preparing a plurality of gallium nitride crystal samples with different iron-doped concentrations N; obtaining sample images of the gallium nitride crystal samples, and performing correction preprocessing on the sample images respectively; calculating coordinates (x, y, Y) of the sample images after the correction preprocessing in the CIExyY color space; wherein x represents red primary color information, y represents green primary color information, and Y represents brightness information; establishing a mapping relationship between x and N, a mapping relationship between y and N, and a mapping relationship between Y and N respectively according to the obtained multiple groups of N and (x, y, Y) corresponding to each other; the mapping relationship between x and N is: ； the mapping relationship between y and N is: Time: ； ： ； the mapping relationship between Y and N is: ； wherein , , , , , , , , , , , , , are the parameters obtained from the fit.

2. The method of claim 1, wherein the concentration of iron doping in the iron-doped gallium nitride crystal is detected by measuring the intensity of the X-ray fluorescence spectrum of the iron-doped gallium nitride crystal. For iron doping concentration of 10 16 cm -3 ~10 20 cm -3 The method further includes: iron-doped gallium nitride crystals within the specified range. calculating 10 16 cm -3 ~10 20 cm -3 corresponding to different iron doping concentrations in the range, and preparing corresponding color blocks according to the obtained chrominance-brightness coordinates. designing a color step color chart according to the prepared multiple color blocks; selecting a color step in the color step color chart that is closest to the chrominance and brightness of the iron-doped gallium nitride crystal, and the iron-doped concentration corresponding to the color step is the iron-doped concentration of the iron-doped gallium nitride crystal.

3. The method of claim 2, wherein the concentration of iron doping in the iron-doped gallium nitride crystal is detected by measuring the intensity of the X-ray fluorescence spectrum of the iron-doped gallium nitride crystal. designing a color step color chart according to the prepared multiple color blocks, specifically comprising: arranging the corresponding color blocks in turn according to the increasing or decreasing trend of the iron-doped concentration to obtain a discrete color step color chart; or, generating continuous color steps and corresponding iron-doped concentrations by using an interpolation method according to the prepared multiple color blocks to prepare a continuous gradual color step color chart.

4. The method of claim 1, wherein the concentration of iron doping in the iron-doped gallium nitride crystal is detected by measuring the intensity of the X-ray fluorescence spectrum of the iron-doped gallium nitride crystal. calculating the chrominance-brightness coordinates of the image after the correction preprocessing in the CIExyY color space, specifically comprising: calculating the RGB value of the gallium nitride crystal in the image after the correction preprocessing; performing normalization processing and gamma correction on the RGB value in turn to obtain a standard sRGB value; converting the standard sRGB value into CIE-XYZ chrominance coordinates in a CIE-XYZ color space; converting the CIE-XYZ chrominance coordinates into chrominance-brightness coordinates in a CIExyY color space.

5. The method of claim 4, wherein the concentration of iron doping in the iron-doped gallium nitride crystal is detected by measuring the intensity of the X-ray fluorescence spectrum of the iron-doped gallium nitride crystal. calculating the RGB value of the gallium nitride crystal in the image after the correction preprocessing, specifically comprising: uniformly selecting a plurality of sampling points along the diagonal in the effective area around the center of the iron-doped gallium nitride crystal in the image after the correction preprocessing, and taking the mean value of the RGB values of the selected plurality of sampling points as the RGB value of the iron-doped gallium nitride crystal.

6. The method of claim 1-5, wherein the concentration of iron doping in the iron-doped gallium nitride crystal is detected by measuring the intensity of the X-ray fluorescence spectrum of the iron-doped gallium nitride crystal. The method can also be used to detect the iron-doped concentration in the iron-doped gallium nitride material, and the method further comprises the following step before obtaining the image: preparing the iron-doped gallium nitride crystal.

7. A system for detecting iron doping concentration in iron-doped gallium nitride crystals, characterized in that, The method comprises the following steps: A color step color card, each color step of which is marked with the iron doping concentration in a gallium nitride crystal, and the marking principle is consistent with the correlation model used in the method for detecting the iron doping concentration in the iron-doped gallium nitride crystal according to any one of claims 1-6; A detector for screening out the color step closest to the color and brightness of the iron-doped gallium nitride crystal from the color step color card, and the iron doping concentration corresponding to the color step is the iron doping concentration of the iron-doped gallium nitride crystal.

8. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the method for detecting the iron doping concentration in the iron-doped gallium nitride crystal according to any one of claims 1-6 when executing the program.

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