Optimisation of the envelope method for characterisation of optical thin film on substrate specimens from their normal incidence transmittance spectrum

Minkov, Dorian; Gavrilov, G. M.; Angelov, George; Moreno, José Manuel Díaz; Vázquez, C; Ruano, Susana Maria Fernandez; Márquez, E.

doi:10.1016/j.tsf.2017.11.003

Cited by 20 publications

(45 citation statements)

References 24 publications

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“…The optimizing envelope method (OEM) [ 28 ] determines optimized values of the above mentioned three parameters, and employs them in the computation of

, ∆d, and the spectral dependencies of the refractive index n ( λ ) and the extinction coefficient k ( λ ) of the film illustrated in Figure 1 .…”

Section: Introductionmentioning

confidence: 99%

“…The smoothed normal incidence transmittance spectrum T sm ( λ ) of the specimen from Figure 1 was formulated in [ 28 ] as:

where:

where T u ( λ ) represents the transmittance of a uniform film on the same substrate, x ( λ ) is the absorbance of the film, and the subscript ‘s’ refers to the respective known substrate characteristics. It is assumed in Equation (1) that the film thickness d has a continuous uniform distribution in the interval (

− ∆d,

+ ∆d) over the light spot on the film surface, as the light passing through the film is considered to be coherent.…”

Section: Introductionmentioning

confidence: 99%

“…Main advantage of the envelope methods (EM) is that they do not employ and dispersion model, as a result of using the interference fringes equation [ 19 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]:

…”

Section: Introductionmentioning

confidence: 99%

“…The AOEM is executed in two stages, as at the end of its first stage are computed both the average thickness

, and the thickness non-uniformity ∆d ≥ 0 of the film over the light spot, as well as the first interference order m 1 (max( λ t )) [ 28 , 29 ]. This is achieved by minimization of an error metric.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Optical Characterization of AsxTe100−x Films Grown by Plasma Deposition Based on the Advanced Optimizing Envelope Method

et al. 2020

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Three AsxTe100−x films with different x and dissimilar average thickness d ¯ are characterized mainly from one interference transmittance spectrum T(λ = 300 to 3000 nm) of such film on a substrate based on the advanced optimizing envelope method (AOEM). A simple dual transformation of T(λ) is proposed and used for increasing the accuracy of computation of its envelopes T+(λ) and T−(λ) accounting for the significant glass substrate absorption especially for λ > 2500 nm. The refractive index n(λ) of As40Te60 and As98Te2 films is determined with a relative error <0.30%. As far as we know, the As80Te20 film is the only one with anomalous dispersion and the thickest, with estimated d ¯ = 1.1446 nm, ever characterized by an envelope method. It is also shown and explained why the extinction coefficient k(λ) of any of the three AsxTe100−x films is computed more accurately from the quantity Ti(λ) = [T+(λ)T−(λ)]0.5 compared to its commonly employed computation from T+(λ). The obtained results strengthen our conviction that the AOEM has a capacity for providing most accurate optical characterization of almost every dielectric or semiconductor film with d ¯ > 300 nm on a substrate, compared to all the other methods for characterization of such films only from T(λ).

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“…The optimizing envelope method (OEM) [ 28 ] determines optimized values of the above mentioned three parameters, and employs them in the computation of

, ∆d, and the spectral dependencies of the refractive index n ( λ ) and the extinction coefficient k ( λ ) of the film illustrated in Figure 1 .…”

Section: Introductionmentioning

confidence: 99%

“…The smoothed normal incidence transmittance spectrum T sm ( λ ) of the specimen from Figure 1 was formulated in [ 28 ] as:

where:

− ∆d,

+ ∆d) over the light spot on the film surface, as the light passing through the film is considered to be coherent.…”

Section: Introductionmentioning

confidence: 99%

…”

Section: Introductionmentioning

confidence: 99%

“…The AOEM is executed in two stages, as at the end of its first stage are computed both the average thickness

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Optical Characterization of AsxTe100−x Films Grown by Plasma Deposition Based on the Advanced Optimizing Envelope Method

et al. 2020

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show abstract

“…On the other hand, when they are deformed, in general, they do not have fringes due to the variation in their thickness, causing destructive interference in the light output of the film. For this reason, research [16,17,[21][22][23][24][25] to propose improvements in the method proposed by Swanepoel for increasingly accurate measurement of the thickness and optical properties of thin films are increasingly common, regardless of how these films were produced.…”

Section: Introductionmentioning

confidence: 99%

Optical-Electrical Properties and Thickness Analysis of TiO2 Thin Films Obtained by Magnetron Sputtering

Sobrinho¹,

Neto

Lima

et al. 2020

Braz J Phys

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The study of thin films with properties that meet specific needs and improve people's quality of life has been the focus of many researchers. However, knowing and controlling the production techniques of these films have been a challenge for the industry of optical-electronic devices, functional coatings, and energy conservation. The thickness of thin films is a parameter that influences the optical and electrical characteristics of these materials, thus being one of the most important information in the plasma deposition process. Because of the need for precision in measuring the thickness of thin transparent films, this work proposes to evaluate the Swanepoel methods (envelope) and the PUMA, computational method, from optical transmittance curves and compare them with the measurements directly made by microscopy. Scanning electronics for thin films of TiO 2 deposited by magnetron sputtering in different conditions. The results of this study showed that the PUMA method is capable of calculating film thicknesses of a few hundred nanometers and with few interference fringes. The PUMA method showed convergence with high precision for films produced with 30 and 60 min of treatment and a difference of 17% for films with 120 min of deposition concerning the measurements made by microscopy.

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Experimental and computational analysis of the Linear and Nonlinear optical properties of Magnesium bis-(8-hydroxyquinoline) thin film

Lougdali

Kouari

Zazoui

et al. 2022

Journal of Alloys and Compounds

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Optimisation of the envelope method for characterisation of optical thin film on substrate specimens from their normal incidence transmittance spectrum

Cited by 20 publications

References 24 publications

Optical Characterization of AsxTe100−x Films Grown by Plasma Deposition Based on the Advanced Optimizing Envelope Method

Optical Characterization of AsxTe100−x Films Grown by Plasma Deposition Based on the Advanced Optimizing Envelope Method

Optical-Electrical Properties and Thickness Analysis of TiO2 Thin Films Obtained by Magnetron Sputtering

Experimental and computational analysis of the Linear and Nonlinear optical properties of Magnesium bis-(8-hydroxyquinoline) thin film

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