Convergence and precision characteristics of finite difference time domain method for the analysis of spectroscopic ellipsometry data at oblique incidence

Foo, Yishu; Zapien, Juan Antonio

doi:10.1016/j.apsusc.2016.12.165

Cited by 4 publications

(2 citation statements)

References 16 publications

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“…The basic components of a simulation for ellipsometry data analysis by using FDTD Solutions are: (1) Bloch boundary conditions (BBC) used in the four boundaries normal to the sample surface, (2) perfect matching for the top and bottom boundaries layer (PML), (3) a plane wave source with an incident angle θ, (4) a data monitor for recording the far-field projected electromagnetic field to calculate the ellipsometric parameters Ψ and ∆, (5) controlling the progress and end of the simulation conditional time monitor, and (6) sample structure [39][40][41].…”

Section: Simulation Resultsmentioning

confidence: 99%

FDTD-Based Study on Equivalent Medium Approximation Model of Surface Roughness for Thin Films Characterization Using Spectroscopic Ellipsometry

Cui

Bian

et al. 2022

Photonics

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Spectroscopic ellipsometry (SE) is an effective method to measure the optical constants of thin film materials which is very sensitive to the surface topography of thin films. When performing ellipsometric measurements of the optical constants of solid materials with rough surfaces, the equivalent medium approximation (EMA) model is often used to characterize the surface topography. The EMA model is determined by two parameters of equivalent thickness dEMA and the void volume fraction f. In most applications, the void volume fraction parameter f is always set to an empirical 50% without any instructions, and then the thickness parameter dEMA is determined by fitting. In order to improve the accuracy of the fitting results, it is necessary to validate the construction law of the EMA model in the ellipsometry analysis considering characteristic parameters of the actual surface topography. In this paper, the influence of the surface topographical parameters on EMA model is analyzed. The method of FDTD (finite difference time domain) is employed to simulate the SiO2 films with different topographical parameters and EMA model are carried out on these samples. The analysis results show that the EMA model constructed with dEMA = σ + 0.80 h (σ: the root mean square height, h: the average height) can better fit the SE parameters. The proposed method can facilitate a better understanding and utilization of the EMA model in SE application.

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Section: Simulation Resultsmentioning

confidence: 99%

FDTD-Based Study on Equivalent Medium Approximation Model of Surface Roughness for Thin Films Characterization Using Spectroscopic Ellipsometry

Cui

Bian

et al. 2022

Photonics

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“…The polarized reflection characteristics from planar multilayer structures can be calculated using Fresnel equations and a matrix transfer algorithm. [16,17,41,42] The FDTD method applied to spectroscopic ellipsometry, [43][44][45] is capable of simulating the ellipsometric response of multilayer structures with sub-nm accuracy when appropriate care is done in using realistic dispersion relationships [n(𝜆), k(𝜆)], calculated from ellipsometry measurements and minimizing well-identified potential sources of errors that include convergence and numerical stability issues present in the FDTD method at large angles of incidence. Using this strategy, we also investigate the conventional SPR and uncoupled optical waveguide configurations, which are compared with our proposed MDM coupled system in Note 2 (Supporting Information).…”

Section: Strong Coupling Of Plasmonic and Photonic Modesmentioning

confidence: 99%

Vernier Ellipsometry Sensing with Ultralow Limit‐of‐Detection and Large Dynamic Range by Tuning of Zero‐Reflection Points

Zhang,

Phoo,

Foo

et al. 2024

Laser & Photonics Reviews

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Optical sensors using zero‐reflection points (ZRPs) enable excellent sensitivity due to the accompanying phase singularities and the steepest slope of the reflectivity curve. Here, the collaborative manipulation of three ZRPs in a simple platform formed by a lithography‐free, metal‐dielectric‐metal structure with unsurpassed, experimentally demonstrated, limit of detection ≈2 × 10−8 refractive index unit is reported. The sensor relies on: i) strong coupling between p‐polarized surface plasmon polariton and photonic waveguide, leading to reflection suppression, Rabi splitting and phase singularities; ii) simultaneous implementation of two orthogonally polarized ZRPs, enabling spectral overlap of s‐polarized photonic modes (Rs) with the coupled p‐polarized resonances (Rp); and iii) ellipsometry‐based sensing where the s‐polarized ZRPs provide a stable reference to boost the sensor performance in terms of the amplitude ratio and phase difference of Rp and Rs thereby naturally forming a refinement measuring scale akin to a Vernier scale. Remarkably, the precise manipulation of ZRPs enables resetting the sensor to its optimal sensing point. The capability has been demonstrated for a biosensor of SARS‐CoV‐2 spike (S2) protein that can track the full functionalization process then reset to perform dose‐dependent detection of the S2 protein. This work provides a new strategy for the development of optical sensors and perfect light absorbers.

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Neural network assisted multi-parameter global sensitivity analysis for nanostructure scatterometry

Meng

Jiang

2021

Applied Surface Science

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Convergence and precision characteristics of finite difference time domain method for the analysis of spectroscopic ellipsometry data at oblique incidence

Cited by 4 publications

References 16 publications

FDTD-Based Study on Equivalent Medium Approximation Model of Surface Roughness for Thin Films Characterization Using Spectroscopic Ellipsometry

FDTD-Based Study on Equivalent Medium Approximation Model of Surface Roughness for Thin Films Characterization Using Spectroscopic Ellipsometry

Vernier Ellipsometry Sensing with Ultralow Limit‐of‐Detection and Large Dynamic Range by Tuning of Zero‐Reflection Points

Neural network assisted multi-parameter global sensitivity analysis for nanostructure scatterometry

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