CN112595673B - Method for measuring optical constant of monocrystalline diamond substrate - Google Patents
Method for measuring optical constant of monocrystalline diamond substrate Download PDFInfo
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/21—Polarisation-affecting properties
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/21—Polarisation-affecting properties
- G01N21/211—Ellipsometry
- G01N2021/213—Spectrometric ellipsometry
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Abstract
The inventionThe invention discloses a method for measuring optical constants of a monocrystalline diamond substrate, which comprises the following steps: respectively measuring the monocrystal diamond substrate by adopting a transmission type ellipsometry mode and a reflection type ellipsometry mode; the transmission spectra (ψ) were obtained by the above measurement, respectively t 、Δ t ) And reflectance spectrum (ψ) r 、Δ r ) The method comprises the steps of carrying out a first treatment on the surface of the According to the measurement, spectrum data are obtained, and a Cauchy model is adopted to calculate respectively so as to obtain substrate optical constants, wherein the optical constants at least comprise a substrate refractive index n and an extinction coefficient k; evaluating the fitting error sigma, and optimizing the optical model or the dielectric function when the fitting error exceeds a preset condition; and comparing the fitting errors of the optimized models, and selecting a model and a measuring mode to determine the optical constant of the diamond substrate. It has the following advantages: the optical constant measurement is more accurate.
Description
Technical Field
The invention relates to the technical field of optical constant measurement, in particular to a method for measuring optical constants of a monocrystalline diamond substrate.
Background
The existing ultra-wideband optical constant testing method for the optical film, such as CN106706521A, comprises the following steps: s1, firstly, depositing an optical film with a preset thickness on a silicon substrate; s2, measuring the transmission spectrum of the ultraviolet to near infrared band elliptical polarization spectrum and the infrared band of the deposited optical film; s3, selecting a transparent region of a section of film according to the spectrum data of the optical film, and calculating to obtain a film refractive index n and a thickness d1 of the wave band range by adopting a Cauchy model; s4, an optical constant model with an optical constant ranging from ultraviolet to infrared is established, a dielectric constant oscillator model is added in an absorption spectrum region, the center frequency of the oscillator is the absorption position, and the amplitude and the width of the oscillator are adjusted according to spectrum data; s5, taking an ultraviolet-to-near infrared band elliptical polarization spectrum and an infrared band transmission spectrum as composite targets, and carrying out inversion operation on the film optical constant in the range from ultraviolet to infrared full spectrum, wherein the initial value of the thickness is set to d1, an evaluation function MSE is preset, the MSE is the mean square error of a measured value and a theoretical model calculated value, and the MSE is fitted to ensure that the smaller the MSE is, the better the MSE is; s6, according to MSE fitting results, obtaining each parameter of a dielectric constant model, and further obtaining the optical constants of the film in the ultraviolet-infrared ultra-wideband spectral range, including the refractive index n, the extinction coefficient k and the physical thickness d of the film. The measurement method only measures and obtains a result according to an ellipsometry mode, so that the accuracy of obtaining a constant is required to be enhanced.
Disclosure of Invention
The invention provides a method for measuring optical constants of a monocrystalline diamond substrate, which overcomes the defects of an ultra-wideband optical constant testing method for an optical film in the background technology.
In order to solve the technical problems, the invention provides a method for measuring optical constants of a monocrystalline diamond substrate, which comprises the following steps:
s1, respectively measuring a monocrystal diamond substrate by adopting a transmission type ellipsometry mode and a reflection type ellipsometry mode;
s2, obtaining transmission spectrums (psi, delta) respectively through the measurement t ) And reflectance spectrum (ψ) r 、Δ r ) The amplitude ratio of the outgoing light to the incoming light is denoted by ψ, the phase difference of the outgoing light and the incoming light is denoted by Δ, the transmission ellipsometry is denoted by subscript t, and the reflection ellipsometry is denoted by subscript r;
s3, obtaining spectral data according to the measurement, and respectively calculating by adopting a Cauchy model to obtain substrate optical constants, wherein the optical constants at least comprise a substrate refractive index n and an extinction coefficient k;
s4, evaluating a fitting error sigma, and optimizing an optical model or a dielectric function when the fitting error exceeds a preset condition;
s5, comparing the fitting errors of the optimized models, and selecting a model and a measuring mode to determine the optical constants of the diamond substrate.
In one embodiment: in this step S2, the transmission spectrum (ψ) t 、Δ t ) The definition is as follows:
reflection spectrum
The definition is as follows:
t represents a polarization amplitude transmission coefficient, r represents a polarization amplitude reflection coefficient, and subscripts p and s represent p-polarized light and s-polarized light decomposed from a beam of natural light, respectively.
In one embodiment: in the step S3, the Cauchy model calculation formula is:
wherein n is refractive index, A n 、B n And C n Is a Cauchy model parameter, lambda is wavelength, and extinction coefficient k is represented by A k 、B k And E is b Description of three parameters, E b ＝1240/λ b ，E b In relation to the substrate material. .
In one embodiment: in the step S4, the calculation formula of the fitting error σ is:
ρ=tan Φexp (iΔ), M is the number of measurement points, P is the number of parameters, subscript ex represents experimental data, subscript cal represents fitted calculation data.
In one embodiment: in step S3, spectral data is obtained from the above measurements using the Cauchy modeCalculated separately to obtain substrate optical constants for the band range, the optical constants further including substrate thickness d t 、d r 。
In one embodiment: the wave band range is 210 nm-1650 nm.
In one embodiment: in this step S4, the optimized optical model comprises a multilayer structure.
In one embodiment: the multilayer structure includes a roughness layer calculated using Bruggeman Effective Media Approximation (EMA) theory.
Compared with the background technology, the technical proposal has the following advantages:
1. through two measurement modes of transmission type and reflection type of ellipsometer, the monocrystal diamond substrate is measured respectively to obtain transmission spectrum and reflection spectrum, then calculation is carried out according to an optical model established by combining the transmission spectrum and the reflection spectrum, the final optical constant of the monocrystal diamond substrate is obtained through fitting analysis, more information can be extracted, and the optical constant is more accurate.
2. The transmission spectrum is defined as
The reflectance spectrum is defined as
The Cauchy model has a calculation formula of +.>
The calculation formula of the fitting error sigma is +.>
The optical constant obtained by modeling through the five formulas is more accurate.
Detailed Description
In order to further explain the objects, technical solutions and features of the present invention, a method for measuring an optical constant of a single crystal diamond substrate will be described in further detail with reference to specific examples.
A method for measuring optical constants of a single crystal diamond substrate, comprising:
s1, respectively measuring a monocrystal diamond substrate by adopting a transmission type ellipsometry mode and a reflection type ellipsometry mode, wherein the measurement mode can be measured by adopting an ellipsometer, and the ellipsometer is an optical measurement instrument for detecting the thickness, optical constants and material microstructure of a film;
s2, obtaining transmission spectra (psi) by the above measurement t 、Δ t ) And reflectance spectrum (ψ) r 、Δ r ) The amplitude ratio of the outgoing light to the incoming light is denoted by ψ, the phase difference of the outgoing light and the incoming light is denoted by Δ, the transmission ellipsometry is denoted by subscript t, and the reflection ellipsometry is denoted by subscript r; wherein:
transmission spectrum (ψ) t 、Δ t ) The definition is as follows:
the reflectance spectrum (ψr, Δr) is defined as:
in formulas (1) and (2): t represents a polarization amplitude transmission coefficient, r represents a polarization amplitude reflection coefficient, and subscripts p and s represent p-polarized light and s-polarized light decomposed by a beam of natural light, respectively;
s3, obtaining spectral data according to the measurement, and respectively calculating by using a Cauchy model (Cauchy model) to obtain substrate optical constants, wherein the optical constants at least comprise the substrate refractive index n t 、n r ；
The Cauchy model calculation formula is:
in formula (3): n is refractive index, A n 、B n And C n Is a Cauchy model parameter, lambda is a wavelength,
in formula (4): the extinction coefficient k is represented by A k 、B k And E is b Description of three parameters, E b ＝1240/λ b Associated with the substrate material;
s4, evaluating a fitting error sigma, and optimizing an optical model or a dielectric function when the fitting error exceeds a preset condition;
the calculation formula of the fitting error sigma is as follows:
in formula (5): ρ=tan ψexp (iΔ), M is the number of measurement points, P is the number of parameters (one point is measured multiple times, the number of measurement times corresponds to the number P), subscript ex represents experimental data, subscript cal represents fitted calculation data; wherein: in ellipsometry, the corresponding parameters are represented and analyzed by means of a matrix, the measurement times are related to the number of matrix elements, and if the matrix is a Mueller matrix of 4*4, the parameters are solved by measuring at least 16 times;
s5, comparing the fitting errors of the optimized models, and selecting a model and a measuring mode to determine the optical constants of the diamond substrate.
If necessary, in this step S4, the optimized optical model comprises a multilayer structure comprising a roughness layer calculated using Bruggeman' S Effective Medium Approximation (EMA) theory.
In this embodiment: whether the error exceeds a predetermined condition such as: judging the coincidence degree of the fitting curve and the measuring curve, wherein the error is large if the coincidence degree is large, and the error is small if the coincidence degree is small; or calculating an MSE value of the evaluation index, and judging whether the MSE value is larger than a preset value, wherein the error is large if the MSE value is larger than the preset value, and the error is small if the MSE value is smaller than the preset value.
According to the need, in the step S3, spectral data is obtained according to the above measurement, and the Cauchy model is used to calculate the optical constants of the substrate in the band range, for example, the surface of the substrate has other film layers, and the thickness d of the surface film layer can be obtained by fitting. The band range is 210nm to 1650nm, and the film thickness d is fitted as a variable parameter with A, B, C of the cauchy model.
The foregoing is only a preferred embodiment of the present invention, but the design concept of the present invention is not limited thereto, and any person skilled in the art will be able to make insubstantial modifications of the present invention within the scope of the present invention disclosed herein by this concept, which falls within the actions of invading the protection scope of the present invention.
Claims (5)
1. A method for measuring optical constants of a monocrystalline diamond substrate is characterized by comprising the following steps of: comprising the following steps:
s1, respectively measuring a monocrystal diamond substrate by adopting a transmission type ellipsometry mode and a reflection type ellipsometry mode;
s2, obtaining transmission spectra (psi) by the above measurement t 、Δ t ) And reflectance spectrum (ψ) r 、Δ r ) The amplitude ratio of the outgoing light to the incoming light is denoted by ψ, the phase difference of the outgoing light and the incoming light is denoted by Δ, the transmission ellipsometry is denoted by subscript t, and the reflection ellipsometry is denoted by subscript r; in this step S2, the transmission spectrum (ψ) t 、Δ t ) The definition is as follows:
the reflectance spectrum (ψr, Δr) is defined as:
t represents a polarization amplitude transmission coefficient, r represents a polarization amplitude reflection coefficient, and subscripts p and s represent p-polarized light and s-polarized light decomposed by a beam of natural light, respectively;
s3, obtaining spectral data according to the measurement, and respectively calculating by adopting a Cauchy model to obtain substrate optical constants, wherein the optical constants at least comprise a substrate refractive index n and an extinction coefficient k; in the step S3, the Cauchy model calculation formula is:
wherein n is refractive index, A n 、B n And C n Is a Cauchy model parameter, lambda is wavelength, and extinction coefficient k is represented by A k 、B k And E is b Description of three parameters, E b ＝1240/λ b ，E b Associated with the substrate material;
s4, evaluating a fitting error sigma, and optimizing an optical model or a dielectric function when the fitting error exceeds a preset condition; in the step S4, the calculation formula of the fitting error σ is:
ρ=tan ψexp (iΔ), M is the number of measurement points, P is the number of parameters, subscript ex represents experimental data, subscript cal represents fitted calculation data;
s5, comparing the fitting errors of the optimized models, and selecting a model and a measuring mode to determine the optical constants of the diamond substrate.
2. A method for measuring optical constants of a single crystal diamond substrate according to claim 1, wherein: in step S3, spectral data is obtained according to the above measurement, and substrate optical constants in the band range are calculated by using Cauchy model, the optical constants further including the substrateBottom thickness d t 、d r 。
3. A method for measuring optical constants of a single crystal diamond substrate according to claim 2, wherein: the wave band range is 210 nm-1650 nm.
4. A method for measuring optical constants of a single crystal diamond substrate according to claim 1, wherein: in this step S4, the optimized optical model comprises a multilayer structure.
5. A method for measuring optical constants of a single crystal diamond substrate according to claim 4, wherein: the multilayer structure includes a roughness layer calculated using Bruggeman Effective Media Approximation (EMA) theory.
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| CN113654995B (en) * | 2021-07-08 | 2022-06-21 | 南京大学 | Method for measuring elliptical polarization spectrum under packaging condition |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102680410A (en) * | 2012-05-03 | 2012-09-19 | 中国科学院宁波材料技术与工程研究所 | Method for non-destructively, quickly and accurately characterizing bonding structure of tetrahedral amorphous carbon film |
| CN103743349A (en) * | 2013-12-30 | 2014-04-23 | 中国科学技术大学 | Method and device for measuring nano film |
| CN106706521A (en) * | 2016-12-12 | 2017-05-24 | 天津津航技术物理研究所 | Optical film ultra wide band optical constant testing method |
| CN107275244A (en) * | 2017-05-10 | 2017-10-20 | 昆山国显光电有限公司 | A kind of chip detection method and device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| EP1406080A4 (en) * | 2001-05-22 | 2006-03-15 | Horiba Ltd | Thin-film characteristic measuring method using spectroellipsometer |
| JP5461020B2 (en) * | 2008-03-05 | 2014-04-02 | 株式会社堀場製作所 | Spectroscopic ellipsometer |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102680410A (en) * | 2012-05-03 | 2012-09-19 | 中国科学院宁波材料技术与工程研究所 | Method for non-destructively, quickly and accurately characterizing bonding structure of tetrahedral amorphous carbon film |
| CN103743349A (en) * | 2013-12-30 | 2014-04-23 | 中国科学技术大学 | Method and device for measuring nano film |
| CN106706521A (en) * | 2016-12-12 | 2017-05-24 | 天津津航技术物理研究所 | Optical film ultra wide band optical constant testing method |
| CN107275244A (en) * | 2017-05-10 | 2017-10-20 | 昆山国显光电有限公司 | A kind of chip detection method and device |
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