Silicon carbide parameter measuring method and device and computer equipment

Abstract

The invention relates to a silicon carbide parameter measuring method and device and computer equipment. The method comprises the following steps: calculating a complex dielectric constant of each film layer based on dispersion model parameters and the number of film layers of a target material; calculating an amplitude reflectivity coefficient of each film layer based on the complex dielectric constant of each film layer; calculating a fitting reflection spectrum of the target material based on the complex dielectric constants, the amplitude reflectivity coefficients and the thickness parameters of the multiple film layers; performing iterative optimization on the dispersion model parameter and the thickness parameter based on an actually measured reflection spectrum and the fitting reflection spectrum; and determining the carrier concentration, mobility and thickness of the target material based on the dispersion model parameters and thickness parameters after iterative optimization. The method can improve the flexibility of silicon carbide parameter measurement.

Description

Technical Field

[0001] The present application relates to the field of measurement technology, and in particular to a method, device and computer equipment for measuring silicon carbide parameters. Background Art

[0002] As a wide bandgap semiconductor material, silicon carbide has been widely used in high-temperature, high-frequency and high-power electronic devices. Among them, carrier concentration is one of the key parameters of silicon carbide materials. The current measurement methods usually use Hall effect measurement, CV characteristic measurement and other methods. However, the above methods will damage the sample itself due to contact measurement, and the measurement is complicated and time-consuming. Traditional technology provides a non-contact measurement method, but this method can only analyze single-layer structures and does not have the ability to measure multi-layer structures, so the measurement flexibility is low.

[0003] Therefore, the current SiC parameter measurement method still has the problem of low measurement flexibility. Summary of the invention

[0004] Based on this, it is necessary to provide a silicon carbide parameter measurement method, device and computer equipment that can improve the flexibility of silicon carbide parameter measurement in order to address the above technical problems.

[0005] In a first aspect, the present application provides a method for measuring silicon carbide parameters, the method comprising: Calculate the complex dielectric constant of each film layer based on the dispersion model parameters and the number of film layers of the target material; Based on the complex dielectric constant of each film layer, the amplitude reflectivity coefficient of each film layer is calculated; Calculating a fitted reflection spectrum of the target material based on complex dielectric constants, amplitude reflectivity coefficients and thickness parameters of multiple film layers; Iteratively optimizing the dispersion model parameters and the thickness parameters based on the measured reflection spectrum and the fitted reflection spectrum; Based on the iteratively optimized dispersion model parameters and thickness parameters, the carrier concentration, mobility and thickness of the target material are determined.

[0006] In one embodiment, the calculating the complex dielectric constant of each film layer based on the dispersion model parameters and the number of film layers of the target material comprises: Get the initial values ​​of dispersion model parameters; The complex dielectric constant of each film layer is calculated based on the initial values ​​of the dispersion model parameters and the dispersion model of the target material.

[0007] In one embodiment, calculating the amplitude reflectivity coefficient of each film layer based on the complex dielectric constant of each film layer includes: Calculate the refractive index and extinction coefficient of each film layer based on the complex dielectric constant and dielectric function model of each film layer; The amplitude reflectivity coefficient of each film layer is calculated based on the refractive index and extinction coefficient of each film layer.

[0008] In one embodiment, the measured reflection spectrum is obtained by measuring the target material at oblique incidence, the amplitude reflectivity coefficient includes a vertical polarized light reflectivity coefficient and a parallel polarized light reflectivity coefficient, and the calculation of the amplitude reflectivity coefficient of each film layer based on the refractive index and extinction coefficient of each film layer includes: Based on the refractive index, extinction coefficient and oblique incident angle of each film layer, the vertical polarized light reflectivity coefficient and the parallel polarized light reflectivity coefficient of each film layer are calculated respectively.

[0009] In one embodiment, the calculating the fitted reflection spectrum of the target material based on the complex dielectric constant, the amplitude reflectivity coefficient and the thickness parameter of the plurality of film layers comprises: Determine the complex refractive index value of each film layer based on the complex dielectric constant of each film layer; Get the initial value of the thickness parameter of each film layer; Recursively calculating the reflection coefficient value of the target material based on the complex refractive index values, amplitude reflectivity coefficients and initial thickness parameter values ​​of the plurality of film layers; Based on the reflectance value of the target material, a fitted reflectance spectrum of the target material is obtained.

[0010] In one embodiment, the amplitude reflectivity coefficient includes a vertical polarized light reflectivity coefficient and a parallel polarized light reflectivity coefficient, the reflectivity value of the target material includes a vertical polarized light reflectivity value and a parallel polarized light reflectivity value, and obtaining the fitted reflectivity spectrum of the target material based on the reflectivity value of the target material includes: Based on the vertically polarized light reflection coefficient value, obtaining the vertically polarized light reflectivity of the target material; Based on the parallel polarized light reflection coefficient value, obtaining the parallel polarized light reflectivity of the target material; Obtaining a total reflection spectrum of the target material based on an average value of the vertically polarized light reflectivity and the parallel polarized light reflectivity; The total reflection spectrum is taken as the fitted reflection spectrum of the target material.

[0011] In one embodiment, before iteratively optimizing the dispersion model parameters and the thickness parameters based on the measured reflection spectrum and the fitted reflection spectrum, the method includes: Based on the infrared spectrum measurement system, the reflection spectrum under the plane mirror is measured to obtain a first reflection spectrum; The plane mirror is replaced by the target material, and the reflection spectrum under the target material is measured to obtain a second reflection spectrum; obtaining a relative reflection spectrum based on the first reflection spectrum and the second reflection spectrum; The relative reflection spectrum is taken as the measured reflection spectrum.

[0012] In one embodiment, the dispersion model parameters include a free carrier damping constant and a free carrier plasma frequency, and the determining of the carrier concentration, mobility and thickness of the target material based on the iteratively optimized dispersion model parameters and thickness parameters includes: Calculating the carrier concentration of the target material based on the free carrier plasma frequency, effective mass, electron charge and high frequency dielectric constant; Calculating the mobility of the target material based on the free carrier damping constant, effective mass and electron charge; The thickness parameter of each film layer after iterative optimization is used as the thickness of each film layer in the target material.

[0013] In a second aspect, the present application provides a silicon carbide parameter measurement device, the silicon carbide parameter measurement device comprising: Complex permittivity calculation module, used to calculate the complex permittivity of each film layer based on the dispersion model parameters and the number of film layers of the target material; An amplitude reflectivity coefficient calculation module, used for calculating the amplitude reflectivity coefficient of each film layer based on the complex dielectric constant of each film layer; A reflection spectrum fitting module, used for calculating the fitting reflection spectrum of the target material based on the complex dielectric constant, amplitude reflectivity coefficient and thickness parameters of multiple film layers; A parameter optimization module, used for iteratively optimizing the dispersion model parameters and the thickness parameters based on the measured reflection spectrum and the fitted reflection spectrum; The parameter determination module is used to determine the carrier concentration, mobility and thickness of the target material based on the iteratively optimized dispersion model parameters and thickness parameters.

[0014] In a third aspect, the present application provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the above-mentioned method when executing the computer program.

[0015] The above-mentioned silicon carbide parameter measurement method, device and computer equipment calculate the complex dielectric constant of each film layer through the dispersion model parameters and the number of film layers of the target material, and then calculate the amplitude reflectivity, and obtain the fitted reflection spectrum. By comparing with the measured reflection spectrum, the parameters are iteratively optimized to obtain the dispersion model parameters and thickness parameters that best match the target material, thereby determining the accurate carrier concentration, mobility and thickness of the target material, and realizing parameter calculation of multiple film layers, thereby achieving the effect of improving the flexibility of silicon carbide parameter measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A diagram showing an application environment of a method for measuring silicon carbide parameters in an embodiment; Figure 2 Schematic diagram of a process of measuring silicon carbide parameters in one embodiment; Figure 3 A schematic diagram of the structure of a device for applying a method for measuring parameters of silicon carbide in one embodiment; Figure 4 is a schematic flow chart of a method for measuring silicon carbide parameters in another embodiment; Figure 5 is a schematic diagram of a reflection spectrum in another embodiment; Figure 6 is a reflection spectrum diagram after fitting in one embodiment; Figure 7 is a structural block diagram of a silicon carbide parameter measurement device in one embodiment; Figure 8 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0018] The silicon carbide parameter measurement method provided in the embodiment of the present application can be applied to Figure 1In the application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be integrated on the server 104, or it can be placed on the cloud or other network servers. The terminal 102 obtains the measured reflection spectrum stored in the server, and the number of film layers of the target material, and calculates the complex dielectric constant of each film layer based on the dispersion model parameters and the number of film layers of the target material; based on the complex dielectric constant of each film layer, the amplitude reflectivity coefficient of each film layer is calculated; based on the complex dielectric constant, amplitude reflectivity coefficient and thickness parameters of multiple film layers, the fitting reflection spectrum of the target material is calculated; based on the measured reflection spectrum and the fitting reflection spectrum, the dispersion model parameters and the thickness parameters are iteratively optimized; based on the iteratively optimized dispersion model parameters and thickness parameters, the carrier concentration, mobility and thickness of the target material are determined. Among them, the terminal 102 can be, but is not limited to, various personal computers, laptops, smart phones, tablet computers and Internet of Things devices, and the Internet of Things devices can be smart testing equipment, etc. The server 104 can be implemented with an independent server or a server cluster consisting of multiple servers.

[0019] In one embodiment, Figure 2 As shown, a method for measuring silicon carbide parameters is provided, and the method is applied to Figure 1 The terminal 102 in the example is used as an example to illustrate, and the following steps are included: Step S100, calculating the complex dielectric constant of each film layer based on the dispersion model parameters and the number of film layers of the target material.

[0020] The target material may be a single-layer or multi-layer material. When the target material is a single-layer material, the number of layers of the target material is 1. When the target material is an N-layer material, the number of layers of the target material is N, where N is a positive integer.

[0021] The dispersion model may be a mathematical model for describing the relationship between the dielectric properties of the target material and the frequency, and further, may be a model for the relationship between the complex dielectric constant of the target material and the frequency and dispersion model parameters. The dispersion model parameters may be parameters required for the dispersion model calculation.

[0022] In this embodiment, the initial dispersion model parameters may be obtained in advance, and then the complex dielectric constant of each film layer is calculated based on the initial dispersion model parameters and the number of film layers of the target material, and in the subsequent iteration process, the complex dielectric constant of each film layer is recalculated based on the dispersion model parameters adjusted by the measured reflection spectrum and the fitted reflection spectrum, so that iterative optimization of the parameters can be achieved. The dispersion model parameters of each film layer may be different, and the thickness parameters may also be different.

[0023] It can be understood that calculating the complex dielectric constant of each film layer based on the dispersion model parameters and the number of film layers of the target material may be calculating the complex dielectric constant of each film layer at different frequencies, and the frequency in this embodiment may be the angular frequency.

[0024] Step S200, calculating the amplitude reflectivity coefficient of each film layer based on the complex dielectric constant of each film layer.

[0025] Among them, the amplitude reflectivity coefficient is also called the amplitude reflection coefficient, which reflects the ratio of the intensity of the reflected light to the intensity of the incident light when the light is incident from one medium to another, that is, the ratio of the radiation flux of the reflected light to the incident light.

[0026] Since the complex dielectric constant is a complex number that describes the electrical response characteristics of a material in an alternating electric field, it can be calculated using electromagnetic field theory. The complex dielectric constant can be used to determine the optical parameters of the material, such as the refractive index, and the optical parameters can be substituted into the electromagnetic field theory to obtain the amplitude reflectivity coefficient.

[0027] Exemplarily, the electromagnetic field theory can be calculated using Fresnel's theorem, the optical parameters of the target material can be calculated using the complex dielectric constant, and the optical parameters can be substituted into Fresnel's theorem to calculate the amplitude reflectivity coefficient.

[0028] Step S300, calculating a fitted reflection spectrum of the target material based on the complex dielectric constants, amplitude reflectivity coefficients and thickness parameters of multiple film layers.

[0029] The fitted reflection spectrum is a theoretical reflection spectrum calculated based on the complex dielectric constant, amplitude reflectivity coefficient and thickness parameters of multiple film layers, and may include the corresponding reflectivity at different wavelengths. An optical model can be constructed through the complex dielectric constant, amplitude reflectivity coefficient and thickness parameters to simulate the theoretical reflection spectrum of the target material within a given wavelength.

[0030] The fitted reflection spectrum of the target material can be calculated by recursively calculating the reflectivity of each film layer based on the complex dielectric constant, amplitude reflectivity coefficient and thickness parameter of each film layer, so as to fit the fitted reflection spectrum corresponding to the current dispersion model parameters and thickness parameters. It can be understood that the obtained fitted reflection spectrum is the reflection spectrum obtained by fitting under the dispersion model parameters and thickness parameters of each film layer.

[0031] Step S400: iteratively optimizing the dispersion model parameters and the thickness parameters based on the measured reflection spectrum and the fitted reflection spectrum.

[0032] Among them, based on the measured reflection spectrum and the fitted reflection spectrum, the dispersion model parameters and the thickness parameters are iteratively optimized. It can be based on an optimization algorithm, such as traversal, particle swarm algorithm, unconstrained optimization algorithm, and according to the difference between the measured reflection spectrum and the fitted reflection spectrum, the dispersion model parameters and the thickness parameters are adjusted, and then the steps of step S100 to step S300 can be repeated according to the adjusted dispersion model parameters and thickness parameters, and the optimization algorithm is repeated to perform analysis and parameter adjustment based on the measured reflection spectrum and the fitted reflection spectrum, so as to achieve iterative optimization of the dispersion model parameters and the thickness parameters.

[0033] Step S500, determining the carrier concentration, mobility and thickness of the target material based on the iteratively optimized dispersion model parameters and thickness parameters.

[0034] Among them, after the iterative optimization is completed, if the fitted reflection spectrum is the same as the measured reflection spectrum or the same area, it means that the current dispersion model parameters and thickness parameters match the optical characteristics of the target material, so that the carrier concentration, mobility and thickness of the target material can be calculated based on the current dispersion model parameters and thickness parameters.

[0035] Exemplarily, for silicon carbide materials, the dispersion model parameters may be converted to obtain carrier concentration and mobility, respectively.

[0036] It can be understood that the carrier concentration, mobility and thickness of the target material can be the carrier concentration, mobility and thickness of each film layer.

[0037] The present embodiment provides a method for measuring parameters of silicon carbide. The complex dielectric constant of each film layer is calculated through dispersion model parameters and the number of film layers of the target material, and then the amplitude reflectivity is calculated, and a fitted reflection spectrum is obtained. By comparing with the measured reflection spectrum, the parameters are iteratively optimized to obtain the dispersion model parameters and thickness parameters that best match the target material, thereby determining the accurate carrier concentration, mobility and thickness of the target material, and realizing parameter calculation of multiple film layers, thereby achieving the effect of improving the flexibility of silicon carbide parameter measurement.

[0038] In one embodiment, the calculating the complex dielectric constant of each film layer based on the dispersion model parameters and the number of film layers of the target material comprises: Get the initial values ​​of dispersion model parameters; The complex dielectric constant of each film layer is calculated based on the initial values ​​of the dispersion model parameters and the dispersion model of the target material.

[0039] In order to start the calculation process, the initial values ​​of the dispersion model parameters may be set. For example, for silicon carbide materials, the initial values ​​of the dispersion model parameters may include parameters such as plasma frequency and damping constant.

[0040] The initial values ​​of the dispersion model parameters can be set based on prior knowledge, such as literature, experience, experimental data, etc. Selecting reasonable initial values ​​can help speed up subsequent iterative optimization and improve the accuracy of the results.

[0041] Furthermore, the complex dielectric constant of each film layer may be calculated based on the initial value of the dispersion model parameter and the dispersion model of the target material. For silicon carbide material, for example, the complex dielectric constant may be calculated using a Drude model, a Lorentz model, etc.

[0042] The present embodiment provides a method for measuring silicon carbide parameters, which obtains initial values ​​of dispersion model parameters, performs preliminary calculation of complex dielectric constants, and optimizes dispersion model parameters after subsequent fitting of reflection spectra. This ensures the smooth progress of the calculation process and adapts to the measurement requirements of multilayer structure materials, thereby achieving the effect of improving the flexibility and applicability of the measurement method.

[0043] In one embodiment, calculating the amplitude reflectivity coefficient of each film layer based on the complex dielectric constant of each film layer includes: Calculate the refractive index and extinction coefficient of each film layer based on the complex dielectric constant and dielectric function model of each film layer; The amplitude reflectivity coefficient of each film layer is calculated based on the refractive index and extinction coefficient of each film layer.

[0044] After the complex dielectric constant is obtained, the refractive index and extinction coefficient of each film layer can be calculated according to the relationship between the complex dielectric constant and the refractive index and extinction coefficient.

[0045] In a specific embodiment, the relationship between the complex dielectric constant, the refractive index and the extinction coefficient is as follows: ε(ω) / ε ∞ =(n-ik) 2 Where ω is the angular frequency, ε(ω) is the complex dielectric constant, and ε ∞ is the high-frequency dielectric constant, n is the refractive index, and k is the extinction coefficient. ∞ In this case, the refractive index n and extinction coefficient k can be calculated.

[0046] Furthermore, the amplitude reflectivity coefficient of each film layer may be calculated based on the refractive index and extinction coefficient of each film layer.

[0047] In a specific embodiment, the Fresnel theorem can be used to calculate the amplitude and phase changes of the reflected and transmitted light at the interface. The complex refractive indices n1 and n2 are obtained by the refractive index and the extinction coefficient, and then the amplitude reflectivity coefficient of a single film layer is calculated by bringing the complex refractive indices n1 and n2 into the Fresnel theorem.

[0048] The present embodiment provides a method for measuring silicon carbide parameters, which can accurately describe the optical properties of the material by extracting the refractive index and extinction coefficient from the complex dielectric constant, thereby accurately calculating the amplitude reflectivity coefficient of each film layer, providing reliable data support for subsequent reflection spectrum fitting and parameter optimization, thereby achieving the effect of improving the flexibility and applicability of the measurement method.

[0049] In one embodiment, the calculating the amplitude reflectivity coefficient of each film layer based on the refractive index and extinction coefficient of each film layer comprises: Based on the refractive index, extinction coefficient and oblique incident angle of each film layer, the vertical polarized light reflectivity coefficient and the parallel polarized light reflectivity coefficient of each film layer are calculated respectively.

[0050] The measured reflection spectrum is obtained by measuring the target material at oblique incidence. The amplitude reflectivity coefficient includes a vertical polarized light reflectivity coefficient and a parallel polarized light reflectivity coefficient.

[0051] It can be understood that, through the measurement and fitting of oblique incidence, the influence of different polarization directions on the reflectivity can be fully considered, thereby improving the accuracy of the measurement.

[0052] Based on the refractive index, extinction coefficient and oblique incident angle of each film layer, the vertical polarized light reflectivity coefficient and the parallel polarized light reflectivity coefficient of each film layer are calculated respectively. The complex refractive index of each film layer can be determined based on the refractive index and the extinction coefficient, and then the vertical polarized light reflectivity coefficient and the parallel polarized light reflectivity coefficient are calculated respectively according to the complex refractive index and the oblique incident angle.

[0053] In a specific embodiment, at oblique incidence, the vertically polarized light reflectivity coefficient r s and the reflectivity coefficient of parallel polarized light r p The formulas are: ,

[0054] in, and is the complex refractive index of a single film layer, which can be calculated from the refractive index n and the extinction coefficient k. is the incident angle, is the refraction angle, where It can be calculated using Snell's law.

[0055] A silicon carbide parameter measurement method provided in this embodiment calculates the vertical polarized light reflectance coefficient and the parallel polarized light reflectance coefficient of each film layer based on the refractive index, extinction coefficient and oblique incident angle of each film layer, respectively, so that the calculation result can be more in line with the actual situation, improve the accuracy and reliability of the measurement, effectively handle the measurement requirements of multi-layer structures, and achieve the effect of improving the flexibility and applicability of the measurement.

[0056] In one embodiment, the calculating the fitted reflection spectrum of the target material based on the complex dielectric constant, the amplitude reflectivity coefficient and the thickness parameter of the plurality of film layers comprises: Determine the complex refractive index value of each film layer based on the complex dielectric constant of each film layer; Get the initial value of the thickness parameter of each film layer; Recursively calculating the reflection coefficient value of the target material based on the complex refractive index values, amplitude reflectivity coefficients and initial thickness parameter values ​​of the plurality of film layers; Based on the reflectance value of the target material, a fitted reflectance spectrum of the target material is obtained.

[0057] Wherein, based on the complex dielectric constant, the complex refractive index value of each film layer is determined. The refractive index and extinction coefficient can be calculated by the complex dielectric constant, and then the complex refractive index is obtained based on the refractive index and extinction coefficient. This embodiment will not be described in detail here.

[0058] The initial value of the thickness parameter of each film layer is obtained, wherein each film layer may be set with the same initial thickness value, or may be set based on preliminary measurement or prior knowledge.

[0059] Based on the complex refractive index values, amplitude reflectivity coefficients and initial thickness parameter values ​​of the multiple film layers, the reflectivity value of the target material is recursively calculated. After obtaining the amplitude reflectivity coefficient, the reflectivity value of the target material is recursively calculated in sequence by combining the complex refractive index value, amplitude reflectivity coefficient and initial thickness parameter value of each film layer. Further, when the incident light is obliquely incident, the reflectivity value may include the reflectivity value of vertically polarized light and parallel polarized light.

[0060] In a specific embodiment, the reflectivity coefficient of each film layer may be calculated from bottom to top in sequence according to the film layers of the target material by a recursive method, and finally the total reflectivity, ie, the reflectivity value, may be obtained.

[0061] A silicon carbide parameter measurement method provided in this embodiment can effectively process the reflection coefficient of a multilayer structure, improve the flexibility and applicability of measurement, and adapt to different wavelengths by recursively calculating the reflection coefficient value of the target material based on the complex refractive index values, amplitude reflectivity coefficients and initial values ​​of thickness parameters of multiple film layers, thereby further optimizing the dispersion model parameters and thickness parameters, thereby achieving the effect of improving the flexibility and applicability of measurement.

[0062] In one embodiment, obtaining the fitted reflection spectrum of the target material based on the reflection coefficient value of the target material includes: Based on the vertically polarized light reflection coefficient value, obtaining the vertically polarized light reflectivity of the target material; Based on the parallel polarized light reflection coefficient value, obtaining the parallel polarized light reflectivity of the target material; Obtaining a total reflection spectrum of the target material based on an average value of the vertically polarized light reflectivity and the parallel polarized light reflectivity; The total reflection spectrum is taken as the fitted reflection spectrum of the target material.

[0063] The amplitude reflectivity coefficient includes a vertical polarized light reflectivity coefficient and a parallel polarized light reflectivity coefficient, and the reflectivity value of the target material includes a vertical polarized light reflectivity value and a parallel polarized light reflectivity value.

[0064] Based on the vertical polarized light reflection coefficient value, the vertical polarized light reflectivity of the target material is obtained. The vertical polarized light reflection coefficient value may be squared to obtain the vertical polarized light reflectivity of the target material.

[0065] Similarly, based on the parallel polarized light reflection coefficient value, the parallel polarized light reflectivity of the target material can be obtained by calculating the square of the parallel polarized light reflection coefficient value to obtain the parallel polarized light reflectivity of the target material.

[0066] The present embodiment provides a method for measuring parameters of silicon carbide, which obtains the vertical polarized light reflectivity and the parallel polarized light reflectivity based on the vertical polarized light reflectivity value and the parallel polarized light reflectivity value, respectively, and obtains the total reflection spectrum of the target material based on the average value of the vertical polarized light reflectivity and the parallel polarized light reflectivity. The total reflectivity of the target material at different wavelengths can be accurately calculated to obtain a fitted reflection spectrum, thereby providing reliable data support for subsequent parameter optimization and performance evaluation, thereby achieving the effect of improving the flexibility and applicability of the measurement.

[0067] In one embodiment, before iteratively optimizing the dispersion model parameters and the thickness parameters based on the measured reflection spectrum and the fitted reflection spectrum, the method includes: Based on the infrared spectrum measurement system, the reflection spectrum under the plane mirror is measured to obtain a first reflection spectrum; The plane mirror is replaced by the target material, and the reflection spectrum under the target material is measured to obtain a second reflection spectrum; obtaining a relative reflection spectrum based on the first reflection spectrum and the second reflection spectrum; The relative reflection spectrum is taken as the measured reflection spectrum.

[0068] Exemplarily, the infrared spectrum measurement system may be implemented using a Fourier transform infrared spectrometer (FTIR), and when measuring silicon carbide materials, a Pike stage may be used for wafer testing.

[0069] In this embodiment, the reflection spectrum can be measured by using a plane mirror as a control group to obtain a first reflection spectrum, and then the plane mirror is replaced with a target material to obtain a reflection spectrum under the target material as a second reflection spectrum.

[0070] Based on the first reflection spectrum and the second reflection spectrum, a relative reflection spectrum can be obtained, and the relative reflection spectrum can be obtained by calculating the ratio of the first reflection spectrum to the second reflection spectrum.

[0071] The present embodiment provides a method for measuring parameters of silicon carbide, which obtains a relative reflection spectrum based on the first reflection spectrum and the second reflection spectrum; using the relative reflection spectrum as the measured reflection spectrum can effectively eliminate the influence of background noise and instrument response of the measurement system itself, improve the accuracy of the measured reflection spectrum, more truly reflect the optical properties of the target material, ensure the comparability of measurement results between different laboratories, improve the degree of standardization of measurements, and thus achieve the effect of improving the flexibility and applicability of measurements.

[0072] In one embodiment, determining the carrier concentration, mobility and thickness of the target material based on the iteratively optimized dispersion model parameters and thickness parameters comprises: Calculating the carrier concentration of the target material based on the free carrier plasma frequency, effective mass, electron charge and high frequency dielectric constant; Calculating the mobility of the target material based on the free carrier damping constant, effective mass and electron charge; The thickness parameter of each film layer after iterative optimization is used as the thickness of each film layer in the target material.

[0073] Wherein, the dispersion model parameters include a free carrier damping constant and a free carrier plasma frequency.

[0074] It is understandable that the dispersion model parameters after iterative optimization often characterize the same parameters as the target material. Therefore, the carrier concentration and mobility can be calculated through the free carrier damping constant and the free carrier plasma frequency.

[0075] The carrier concentration can be calculated by using the relationship between the free carrier plasma frequency and the carrier concentration.

[0076] In a specific embodiment, the relationship between the free carrier plasma frequency and the carrier concentration is as follows:

[0077] in, ω p is the free carrier plasma frequency, N is the carrier concentration, e is the electron charge, is the effective mass, ε ∞ is the high frequency dielectric constant.

[0078] The mobility can be calculated using the relationship between the free carrier damping constant and the mobility.

[0079] In a specific embodiment, the relationship between the free carrier damping constant and the mobility is as follows:

[0080] in, is the free carrier damping constant, μ is the mobility, e is the electron charge, is the effective mass.

[0081] The present embodiment provides a method for measuring silicon carbide parameters. The carrier concentration of the target material can be accurately calculated through the free carrier plasma frequency, effective mass, electron charge and high-frequency dielectric constant. The mobility of the target material can be accurately calculated through the free carrier damping constant, effective mass and electron charge, thereby realizing the measurement of silicon carbide parameters and achieving the effect of improving the flexibility and applicability of the measurement.

[0082] In order to more clearly illustrate the technical solution of the present application, the present application also provides a detailed embodiment.

[0083] In one embodiment, a method for measuring silicon carbide parameters is provided, which is applied to a measuring device as follows: Figure 3As shown, the measuring device includes: Fourier infrared spectrometer (FTIR), Pike stage for wafer testing. The device specifically includes: infrared light source, fixed plane mirror, aperture, beam splitter, moving plane mirror (moving mirror), Pike stage and detector, and the fixed plane mirrors are M1, M2 and M3 respectively. The light emitted by the infrared light source propagates as shown in the optical path diagram, and is eventually reflected to the detector by the plane mirror or wafer on the Pike stage. After processing, the reflectivity spectrum that characterizes the characteristics of the wafer can be obtained.

[0084] like Figure 4 As shown, the silicon carbide parameter measurement method includes: (1) Spectral data collection: When a plane mirror is placed on the stage 9, the background spectrum of the air can be collected on the detector. When the plane mirror on the stage is replaced with a wafer sample, the light reflected back to the detector will carry the thickness and electrical parameter characteristics of the sample, which can be obtained by analyzing the relative reflectivity of the sample. The relative reflectivity of the sample can be obtained by dividing the reflected light intensity of the sample with the reflected light intensity of the background.

[0085]

[0086] in, is the reflected light intensity of the sample, is the reflected light intensity of the plane mirror, is the relative reflectivity of the sample.

[0087] By using the relative reflectivity spectrum obtained by the system, combined with the modified classical dielectric function (MDF) model, and considering the influence of the multilayer film structure and the incident angle on the reflectivity, the reflectivity can be solved by the Fresnel theorem and the recursive method. By comparing the difference between the simulated relative reflectivity and the measured reflectivity, the carrier concentration and mobility corresponding to the minimum error and the thickness information of each film layer structure can be analyzed using least squares or other loss functions.

[0088] (2) Model parameters and recipe initialization: Figure 5 The sample reflection spectrum results obtained by the system include the measurement curves with wave number as the x-axis and reflectance as the y-axis. It can be seen that the reflection spectrum contains the result of LO-TO phonon oscillation, that is, a stronger reflection band; as well as the interference fringe information caused by the thickness of the film.

[0089] To obtain the electrical parameters and thickness to be measured by fitting, it is necessary to know the values ​​of the refractive index n and extinction coefficient k of the sample at different frequencies. The refractive index n and extinction coefficient k can be calculated by the dielectric function model of the material.

[0090] The dispersion model of SiC material can be characterized by the following function:

[0091] in, is the high frequency dielectric constant, and are the transverse optical (TO) and longitudinal optical (LO) phonon frequencies, and are the TO and LO phonon damping constants, is the free carrier damping constant, is the free-carrier plasma frequency. is the optical constant value corresponding to different frequencies. The dispersion model of each layer of SiC can be expressed by this optical constant. The difference is that the setting of the above parameters for different layers will be determined according to the actual situation of the film. Its value has the following relationship with the refractive index n and the extinction coefficient k:

[0092] Therefore, through and Get the values ​​of refractive index n and extinction coefficient k.

[0093] Furthermore, in order to obtain the carrier concentration value of the sample to be tested, it is necessary to use the plasma frequency To convert, the expression is:

[0094] Where N is the free carrier concentration, e is the electron charge, is the effective mass.

[0095] Free carrier damping constant is the scattering time The reciprocal of the free carrier mobility It can be obtained through the following relationship:

[0096] Therefore, the reflection spectrum is fitted to achieve and By solving the problem, the carrier concentration and mobility can be calculated. In the calculation process, it is necessary to first give the estimated values ​​of the initial carrier concentration and mobility of different layers of the SiC material according to the actual situation of the sample to be tested, as the initial values, and then solve them through the process of parameter optimization. For one layer of substrate, 7 parameters are needed. After adding one epitaxial layer, the number of parameters becomes 14. When more layers are added, the parameters are similar. In a specific embodiment, a 6-layer structure can be included.

[0097] (3) Fresnel theorem is used to calculate the amplitude reflectivity of each medium surface: In order to obtain the reflectivity, the amplitude reflectivity of each dielectric surface can be calculated by the Fresnel theorem to solve the amplitude reflectivity of each dielectric surface of the wafer to be tested. The Fresnel theorem describes the reflection and transmission of light on the dielectric interface. For vertical incidence and oblique incidence, the amplitude reflectivity coefficients are: At vertical incidence:

[0098] At oblique incidence:

[0099] in: and is the complex refractive index of the medium, satisfying , is the angle of incidence, The refraction angle can be calculated according to Snell's law. In the system, the angle of incidence will be adjusted according to the needs, and then the amplitude reflectivity coefficient of different models needs to be selected to solve the formula. This system uses oblique incidence to illuminate the sample, and the combined effect of s light and p light needs to be considered. Among them, s light is vertically polarized light, and p light is parallel polarized light.

[0100] (4) Calculate reflectivity In addition to the dielectric reflectivity coefficient of each layer, the thickness of each layer needs to be introduced in the process of solving the reflectivity. Assume that the thickness of each layer of the wafer to be tested is , the complex refractive index value calculated using the dispersion model For a multilayer film structure, the recursive method can be used to calculate the absolute reflectivity of each layer of the medium from bottom to top, first calculating the reflectivity coefficient of each medium surface, and then calculating the total reflectivity. The following is an implementation method for calculating the reflectivity value of the i+1th layer under the recursive method:

[0101] in, is the phase shift of light propagating in the i-th layer, and its relationship with the thickness of the i-th film is:

[0102] in, For n-layer thin films, it is necessary to calculate r12, r23...r(i-1,i)...r(n-1,n) of each dielectric interface separately, and then derive the total s-light and p-light reflection coefficient values.

[0103] Finally, the total reflectivity can be calculated as follows: ,and

[0104] in, R s and R p They are the reflectivity of s light and p light respectively. When incident at a small angle, the average of the two can be taken. is the total reflectivity.

[0105] Determine whether the current medium surface is air. If not, continue to calculate the reflection coefficient value. If so, calculate the root mean square value of the theoretical spectrum value and the actual measured spectrum as the fitting error.

[0106] The parameter values ​​are adjusted by the optimization algorithm to obtain the parameters corresponding to the minimum error between the actual measured reflection spectrum and the fitted reflection spectrum. The specific calculation process is:

[0107] Where err is the objective function of the optimization calculation, is the actual measured reflectance spectrum, is the reflectance spectrum fitted by the model.

[0108] In this embodiment, the optimization algorithm that can be used is traversal, particle swarm algorithm, and unconstrained optimization algorithm, which iterates the dispersion model and thickness parameter values ​​to achieve the optimal carrier concentration and thickness solution. When the film layer structure is increased, it means that more parameters need to be set. In the spectral fitting range, different intervals are selected according to the situation of the multilayer film structure to achieve parameter analysis.

[0109] Determine whether the fitting error satisfies the optimization result. If not, continue to perform the optimization step. If yes, output the optimal parameter value and the target thickness value to be measured. In a specific embodiment, the reflection spectrum of a target material after fitting is as follows: Figure 6 As shown, including the measurement curve and the fitting curve with wave number as the x-axis and reflectance as the y-axis, after fitting, the thickness of the epitaxial layer is 5.5666um, the substrate carrier concentration is 4.8074e+18cm-3, the epitaxial layer carrier concentration is 7.5585e+15cm-3, and the goodness of fit is 0.9925.

[0110] The present embodiment provides a method for measuring silicon carbide parameters. The complex dielectric constant of each film layer is calculated by the dispersion model parameters and the number of film layers of the target material, and then the amplitude reflectivity is calculated, and the fitting reflection spectrum is obtained. By comparing with the measured reflection spectrum, the parameters are iteratively optimized, and the dispersion model parameters and thickness parameters that best match the target material can be obtained, so as to accurately determine the carrier concentration, mobility and thickness of the target material, and the parameter calculation of multiple film layers can be realized, so as to achieve the effect of improving the flexibility of silicon carbide parameter measurement. By obtaining the initial value of the dispersion model parameter, performing a preliminary calculation of the complex dielectric constant, and optimizing the dispersion model parameters after the subsequent fitting reflection spectrum, the smooth progress of the calculation process can be ensured, and the measurement requirements of multi-layer structure materials can be adapted, so as to achieve the effect of improving the flexibility and applicability of the measurement method. By extracting the refractive index and extinction coefficient from the complex dielectric constant, the optical properties of the material can be accurately described, so as to accurately calculate the amplitude reflectivity coefficient of each film layer, and provide reliable data support for the subsequent reflection spectrum fitting and parameter optimization, so as to achieve the effect of improving the flexibility and applicability of the measurement method. By calculating the vertical polarized light reflectivity coefficient and the parallel polarized light reflectivity coefficient of each film layer based on the refractive index, extinction coefficient and oblique incident angle of each film layer, the calculation results can be made more in line with the actual situation, the accuracy and reliability of the measurement are improved, the measurement requirements of the multilayer structure are effectively handled, and the flexibility and applicability of the measurement are improved. By recursively calculating the reflectivity value of the target material based on the complex refractive index value, amplitude reflectivity coefficient and initial value of thickness parameter of multiple film layers, the reflectivity of the multilayer structure can be effectively handled, thereby further optimizing the dispersion model parameters and thickness parameters, and the flexibility and applicability of the measurement can be improved. By obtaining the vertical polarized light reflectivity and the parallel polarized light reflectivity based on the vertical polarized light reflectivity value and the parallel polarized light reflectivity value, and obtaining the total reflection spectrum of the target material based on the average value of the vertical polarized light reflectivity and the parallel polarized light reflectivity, the total reflectivity of the target material at different wavelengths can be accurately calculated, and the fitting reflection spectrum can be obtained, which provides reliable data support for subsequent parameter optimization and performance evaluation, and the flexibility and applicability of the measurement can be improved. By obtaining a relative reflection spectrum based on the first reflection spectrum and the second reflection spectrum; and using the relative reflection spectrum as the measured reflection spectrum, the background noise of the measurement system itself and the influence of the instrument response can be effectively eliminated, the accuracy of the measured reflection spectrum can be improved, the optical properties of the target material can be more truly reflected, and the comparability of measurement results between different laboratories can be ensured, and the degree of standardization of the measurement can be improved, thereby achieving the effect of improving the flexibility and applicability of the measurement.The carrier concentration of the target material can be accurately calculated through the free carrier plasma frequency, effective mass, electron charge and high-frequency dielectric constant. The mobility of the target material can be accurately calculated through the free carrier damping constant, effective mass and electron charge, thereby realizing the measurement of silicon carbide parameters and achieving the effect of improving the flexibility and applicability of the measurement.

[0111] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0112] Based on the same inventive concept, the embodiment of the present application also provides a silicon carbide parameter measurement device for implementing the silicon carbide parameter measurement method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more silicon carbide parameter measurement device embodiments provided below can refer to the limitations of the silicon carbide parameter measurement method above, and will not be repeated here.

[0113] In one embodiment, Figure 7 As shown, a silicon carbide parameter measurement device is provided, and the silicon carbide parameter measurement device comprises: The complex dielectric constant calculation module 100 is used to calculate the complex dielectric constant of each film layer based on the dispersion model parameters and the number of film layers of the target material.

[0114] The amplitude reflectivity coefficient calculation module 200 is used to calculate the amplitude reflectivity coefficient of each film layer based on the complex dielectric constant of each film layer.

[0115] The reflection spectrum fitting module 300 is used to calculate the fitting reflection spectrum of the target material based on the complex dielectric constant, amplitude reflectivity coefficient and thickness parameters of multiple film layers.

[0116] The parameter optimization module 400 is used to iteratively optimize the dispersion model parameters and the thickness parameters based on the measured reflection spectrum and the fitted reflection spectrum.

[0117] The parameter determination module 500 is used to determine the carrier concentration, mobility and thickness of the target material based on the iteratively optimized dispersion model parameters and thickness parameters.

[0118] In one embodiment, the complex dielectric constant calculation module 100 is further used for: Get the initial values ​​of dispersion model parameters; The complex dielectric constant of each film layer is calculated based on the initial values ​​of the dispersion model parameters and the dispersion model of the target material.

[0119] In one embodiment, the amplitude reflectivity coefficient calculation module 200 is further used for: Calculate the refractive index and extinction coefficient of each film layer based on the complex dielectric constant and dielectric function model of each film layer; The amplitude reflectivity coefficient of each film layer is calculated based on the refractive index and extinction coefficient of each film layer.

[0120] In one embodiment, the measured reflection spectrum is obtained by measuring the target material at oblique incidence, the amplitude reflectivity coefficient includes a vertical polarized light reflectivity coefficient and a parallel polarized light reflectivity coefficient, and the amplitude reflectivity coefficient calculation module 200 is further used to: Based on the refractive index, extinction coefficient and oblique incident angle of each film layer, the vertical polarized light reflectivity coefficient and the parallel polarized light reflectivity coefficient of each film layer are calculated respectively.

[0121] In one embodiment, the reflection spectrum fitting module 300 is further used for: Determine the complex refractive index value of each film layer based on the complex dielectric constant of each film layer; Get the initial value of the thickness parameter of each film layer; Recursively calculating the reflection coefficient value of the target material based on the complex refractive index values, amplitude reflectivity coefficients and initial thickness parameter values ​​of the plurality of film layers; Based on the reflectance value of the target material, a fitted reflectance spectrum of the target material is obtained.

[0122] In one embodiment, the amplitude reflectivity coefficient includes a vertical polarized light reflectivity coefficient and a parallel polarized light reflectivity coefficient, the reflectivity value of the target material includes a vertical polarized light reflectivity value and a parallel polarized light reflectivity value, and the reflection spectrum fitting module 300 is further used to: Based on the vertically polarized light reflection coefficient value, obtaining the vertically polarized light reflectivity of the target material; Based on the parallel polarized light reflection coefficient value, obtaining the parallel polarized light reflectivity of the target material; Obtaining a total reflection spectrum of the target material based on an average value of the vertically polarized light reflectivity and the parallel polarized light reflectivity; The total reflection spectrum is taken as the fitted reflection spectrum of the target material.

[0123] In one embodiment, the device further comprises a reflection spectrum measurement module, which is used to: Based on the infrared spectrum measurement system, the reflection spectrum under the plane mirror is measured to obtain a first reflection spectrum; The plane mirror is replaced by the target material, and the reflection spectrum under the target material is measured to obtain a second reflection spectrum; obtaining a relative reflection spectrum based on the first reflection spectrum and the second reflection spectrum; The relative reflection spectrum is taken as the measured reflection spectrum.

[0124] In one embodiment, the dispersion model parameters include a free carrier damping constant and a free carrier plasma frequency, and the parameter determination module 500 is further used to: Calculating the carrier concentration of the target material based on the free carrier plasma frequency, effective mass, electron charge and high frequency dielectric constant; Calculating the mobility of the target material based on the free carrier damping constant, effective mass and electron charge; The thickness parameter of each film layer after iterative optimization is used as the thickness of each film layer in the target material.

[0125] Each module in the above silicon carbide parameter measurement device can be implemented in whole or in part by software, hardware and a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each module above.

[0126] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 8As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for measuring silicon carbide parameters is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0127] Those skilled in the art will understand that Figure 8 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0128] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the silicon carbide parameter measurement method of any of the above embodiments is implemented: Calculate the complex dielectric constant of each film layer based on the dispersion model parameters and the number of film layers of the target material; Based on the complex dielectric constant of each film layer, the amplitude reflectivity coefficient of each film layer is calculated; Calculating a fitted reflection spectrum of the target material based on complex dielectric constants, amplitude reflectivity coefficients and thickness parameters of multiple film layers; Iteratively optimizing the dispersion model parameters and the thickness parameters based on the measured reflection spectrum and the fitted reflection spectrum; Based on the iteratively optimized dispersion model parameters and thickness parameters, the carrier concentration, mobility and thickness of the target material are determined.

[0129] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the silicon carbide parameter measurement method of any of the above embodiments is implemented: Calculate the complex dielectric constant of each film layer based on the dispersion model parameters and the number of film layers of the target material; Based on the complex dielectric constant of each film layer, the amplitude reflectivity coefficient of each film layer is calculated; Calculating a fitted reflection spectrum of the target material based on complex dielectric constants, amplitude reflectivity coefficients and thickness parameters of multiple film layers; Iteratively optimizing the dispersion model parameters and the thickness parameters based on the measured reflection spectrum and the fitted reflection spectrum; Based on the iteratively optimized dispersion model parameters and thickness parameters, the carrier concentration, mobility and thickness of the target material are determined.

[0130] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0131] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0132] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0133] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for measuring silicon carbide parameters, characterized in that: The silicon carbide parameter measurement method comprises: Calculate the complex dielectric constant of each film layer based on the dispersion model parameters and the number of film layers of the target material; Based on the complex dielectric constant of each film layer, the amplitude reflectivity coefficient of each film layer is calculated; Calculating a fitted reflection spectrum of the target material based on complex dielectric constants, amplitude reflectivity coefficients and thickness parameters of multiple film layers; Iteratively optimizing the dispersion model parameters and the thickness parameters based on the measured reflection spectrum and the fitted reflection spectrum; Based on the iteratively optimized dispersion model parameters and thickness parameters, the carrier concentration, mobility and thickness of the target material are determined.

2. The method for measuring silicon carbide parameters according to claim 1, characterized in that: The calculation of the complex dielectric constant of each film layer based on the dispersion model parameters and the number of film layers of the target material includes: Get the initial values ​​of dispersion model parameters; The complex dielectric constant of each film layer is calculated based on the initial values ​​of the dispersion model parameters and the dispersion model of the target material.

3. The method for measuring silicon carbide parameters according to claim 1, characterized in that: The calculation of the amplitude reflectivity coefficient of each film layer based on the complex dielectric constant of each film layer includes: Calculate the refractive index and extinction coefficient of each film layer based on the complex dielectric constant and dielectric function model of each film layer; The amplitude reflectivity coefficient of each film layer is calculated based on the refractive index and extinction coefficient of each film layer.

4. The method for measuring silicon carbide parameters according to claim 3, characterized in that: The measured reflection spectrum is obtained by measuring the target material at oblique incidence, the amplitude reflectivity coefficient includes a vertical polarized light reflectivity coefficient and a parallel polarized light reflectivity coefficient, and the amplitude reflectivity coefficient of each film layer is calculated based on the refractive index and extinction coefficient of each film layer, including: Based on the refractive index, extinction coefficient and oblique incident angle of each film layer, the vertical polarized light reflectivity coefficient and the parallel polarized light reflectivity coefficient of each film layer are calculated respectively.

5. The method for measuring silicon carbide parameters according to claim 1, characterized in that: The calculating the fitted reflection spectrum of the target material based on the complex dielectric constant, the amplitude reflectivity coefficient and the thickness parameter of the plurality of film layers comprises: Determine the complex refractive index value of each film layer based on the complex dielectric constant of each film layer; Get the initial value of the thickness parameter of each film layer; Recursively calculating the reflection coefficient value of the target material based on the complex refractive index values, amplitude reflectivity coefficients and initial thickness parameter values ​​of the plurality of film layers; Based on the reflectance value of the target material, a fitted reflectance spectrum of the target material is obtained.

6. The method for measuring silicon carbide parameters according to claim 5, characterized in that: The amplitude reflectivity coefficient includes a vertical polarized light reflectivity coefficient and a parallel polarized light reflectivity coefficient, the reflectivity value of the target material includes a vertical polarized light reflectivity value and a parallel polarized light reflectivity value, and obtaining the fitted reflectivity spectrum of the target material based on the reflectivity value of the target material includes: Based on the vertically polarized light reflection coefficient value, obtaining the vertically polarized light reflectivity of the target material; Based on the parallel polarized light reflection coefficient value, obtaining the parallel polarized light reflectivity of the target material; Obtaining a total reflection spectrum of the target material based on an average value of the vertically polarized light reflectivity and the parallel polarized light reflectivity; The total reflection spectrum is taken as the fitted reflection spectrum of the target material.

7. The method for measuring silicon carbide parameters according to claim 1, characterized in that: Before the iterative optimization of the dispersion model parameters and the thickness parameters based on the measured reflection spectrum and the fitted reflection spectrum comprises: Based on the infrared spectrum measurement system, the reflection spectrum under the plane mirror is measured to obtain a first reflection spectrum; The plane mirror is replaced by the target material, and the reflection spectrum under the target material is measured to obtain a second reflection spectrum; obtaining a relative reflection spectrum based on the first reflection spectrum and the second reflection spectrum; The relative reflection spectrum is taken as the measured reflection spectrum.

8. The method for measuring silicon carbide parameters according to claim 1, characterized in that: The dispersion model parameters include a free carrier damping constant and a free carrier plasma frequency, and the determination of the carrier concentration, mobility and thickness of the target material based on the iteratively optimized dispersion model parameters and thickness parameters includes: Calculating the carrier concentration of the target material based on the free carrier plasma frequency, effective mass, electron charge and high frequency dielectric constant; Calculating the mobility of the target material based on the free carrier damping constant, effective mass and electron charge; The thickness parameter of each film layer after iterative optimization is used as the thickness of each film layer in the target material.

9. A silicon carbide parameter measurement device, characterized in that: The silicon carbide parameter measuring device comprises: Complex permittivity calculation module, used to calculate the complex permittivity of each film layer based on the dispersion model parameters and the number of film layers of the target material; An amplitude reflectivity coefficient calculation module, used for calculating the amplitude reflectivity coefficient of each film layer based on the complex dielectric constant of each film layer; A reflection spectrum fitting module, used for calculating the fitting reflection spectrum of the target material based on the complex dielectric constant, amplitude reflectivity coefficient and thickness parameters of multiple film layers; A parameter optimization module, used for iteratively optimizing the dispersion model parameters and the thickness parameters based on the measured reflection spectrum and the fitted reflection spectrum; The parameter determination module is used to determine the carrier concentration, mobility and thickness of the target material based on the iteratively optimized dispersion model parameters and thickness parameters.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 8 is implemented.

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