Comparative study of the accuracy of characterization of thin films a-Si on glass substrates from their interference normal incidence transmittance spectrum by the Tauc-Lorentz-Urbach, the Cody-Lorentz-Urbach, the optimized envelopes and the optimized graphical methods

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

“…The OEM [ 28 ] was developed for increasing the accuracy of characterization of a thin film on a substrate from interference T ( λ ) of the specimen, by optimization of the three parameters of the IEM from [ 27 ], accounting for possible non-uniformity of the film and substrate absorption. It was demonstrated in [ 34 ] that the OEM from [ 28 ] provides most accurate characterization of a-Si films with dissimilar thicknesses compared to the OGM [ 35 ], TLUM [ 36 ], and CLUM [ 37 ] selected as the most likely methods for accurate characterization of these films. Further increasing the characterization accuracy was achieved by the AOEM [ 29 ] based on: external smoothing of T ( λ ) offsetting the influence of light scattering, enhanced computation of the envelopes using both iteration and extra points, and computation of n ( λ ) and k ( λ ) by optimized curve fitting.…”

“…Based on using FOM from Equation (7), it was shown in [ 28 ] that the OEM provides more accurate film characterization compared to the FEM and the IEM, for all specimens studied there. Furthermore, FOM s were compared in [ 34 ] for characterizations of sputtered a-Si thin films with dissimilar average thicknesses by the OEM, the optimizing graphical method (OGM) [ 35 ], the Tauc–Lorentz–Urbach model method (TLUM) [ 36 ], and the Cody–Lorentz–Urbach model method (CLUM) [ 37 ]. These four film characterization methods were selected as most likely to provide accurate characterization of the a-Si films.…”

“…These four film characterization methods were selected as most likely to provide accurate characterization of the a-Si films. The results from [ 34 ] showed that the OEM provided most accurate characterization of the films, among the four different characterization methods. The superior performance of the OEM was explained considering that it does not assume particular band tails shapes, unlike the TLUM and CLUM, and it does not assume existence of a wide spectral region of film transparency as an initial approximation, unlike the OGM [ 34 ].…”

“…The results from [ 34 ] showed that the OEM provided most accurate characterization of the films, among the four different characterization methods. The superior performance of the OEM was explained considering that it does not assume particular band tails shapes, unlike the TLUM and CLUM, and it does not assume existence of a wide spectral region of film transparency as an initial approximation, unlike the OGM [ 34 ]. Importantly, the accuracy of characterization of the same a-Si films was further increased in [ 29 ] by using the AOEM, compared to the OEM from [ 28 ].…”

Further Increasing the Accuracy of Characterization of a Thin Dielectric or Semiconductor Film on a Substrate from Its Interference Transmittance Spectrum

“…An EM for T ( λ ), providing and using optimized values of these three parameters, was presented in [ 43 ]. Moreover, a comparative study [ 44 ] showed that the EM for T ( λ ), from [ 43 ], furnishes the most accurate characterization of two a-Si films (with very different average thicknesses ( ) amongst four methods, selected as most likely to render accurate characterization of such films. Furthermore, corrections of the envelopes of T sm ( λ ) obtained as in the case of the transparent substrate, only at λ t corresponding to notable substrate absorption, resulted in increasing the accuracy of the characterization of these films [ 45 ].…”