Measurement of optical constants of thin a-C:H films

Souza, Danilo Rodrigues de; Soares, Leandro L.; Cescato, Lucila; Alves, Marco Túlio Santana; Braga, Edmundo S.

doi:10.1016/s0026-2692(99)00111-1

Cited by 10 publications

(5 citation statements)

References 6 publications

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“…As substrates, we used (i) aluminum-coated glass substrates for reflection−absorption measurements, (ii) KBr disks for transmission measurements, and (iii) silicon wafers for thickness and refractive index measurements. Film thicknesses were determined using a profilemeter (Veeco-Dektak3), and the refractive indices were measured using the Abèles method employing the 632.8 nm line of a He−Ne laser . The deposition conditions were labeled as S1, S2, S3, and S4 according to an increasing flow rate of oxygen in the discharge.…”

Section: Methodsmentioning

confidence: 99%

LO−TO Splittings in Plasma-Deposited Siloxane Films

2003

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The present work presents LO and TO functions in the mid-infrared region for thin films deposited from glow discharge plasmas of tetramethylsilane (TMS) diluted either in Ar or O2 or in mixtures of these two gases. These functions were calculated through the Kramers−Krönig analysis of transmittance spectra of the films supported on KBr disks. To correlate structural aspects of the films with the observed LO−TO splittings, a group frequency analysis based on the literature was made. Such an analysis indicated that the films deposited from the TMS−Ar mixture were formed mainly by a polycarbosilane skeleton, whereas those deposited from TMS−O2 and TMS−O2−Ar were formed by a random network of four types of distorted tetrahedra: (CH3)3SiO0.5, (CH3)2SiO, (CH3SiO1.5), and SiO2. From the LO−TO splitting for the asymmetrical stretching mode of Si−O−Si groups, the density and the presence of defects in samples obtained from TMS−O2 and TMS−O2−Ar mixtures were evaluated. The number of defects increased as the Ar-to-O2 flow rate decreased. We also report for the first time LO−TO splittings for bands related to the bending of CH3 and to the stretching of the Si−C bond in Si(CH3) x groups. The knowledge of such splittings is very important for a correct evaluation of the infrared reflection−absorption spectra taken at oblique incidence of thin films containing Si−O bonds and Si(CH3) x groups deposited on metals.

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Section: Methodsmentioning

confidence: 99%

LO−TO Splittings in Plasma-Deposited Siloxane Films

2003

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“…Therefore, the optical constants ðn; a; kÞ can be determined from the reflectance and transmittance measurements by solving Eqs. (1)-(4) [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] at various combination conditions (the measurements from the front or back side, the normal or oblique or multiple angles incidence, the perpendicular or parallel polarized or unpolarized radiation). For three-layer semi-transparent structure, the measurements of the target layer were affected by two side window layers.…”

Section: Radiative Transfer Modelmentioning

confidence: 99%

“…The spectrophotometric method was wildly used to determine the optical constants of thin films from the reflectance and transmittance measurements based on the minimization process of the difference between the calculated and the measured values [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], or based on the interference fringe patterns process [24][25][26][27][28][29][30]. And various combinations of measured quantities at various conditions (the transmittance, the reflectance from the front or back side, the normal or oblique or multiple angles incidence, the perpendicular or parallel polarized radiation) can be used.…”

Section: Introductionmentioning

confidence: 99%

Measurement method for high-temperature infrared optical constants of ZnS crystal materials in a multi-layer structure

Liu

2015

Infrared Physics & Technology

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“…This parameter was obtained from its transmittance spectra. Once its thickness is known, it is possible to use the Lambert-Beer law (21,22), taking into account the reflections of the three interfaces:…”

Section: Ecs Transactions 39 (1) 439-446 (2011)mentioning

confidence: 99%

Process Modeling and Fabrication of Microlens Array in Thick Photoresist

2011

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In this work, the design and fabrication of a low f-number cylindrical microlens array is presented. The lenses were fabricated in thick photo resist of 12 μm thickness, using a contact printer exposure through a mask with a repetitive 6 μm line - 4 μm space pattern. Numerical calculations based on scalar diffraction theory were employed to model the light propagation inside the resist, determining the aerial image as a function of its thickness. Than the resist response characteristics, expressed by its contrast curve, and absorption rate were used to obtain a cross section profile. A good match between numerical and experimental results were found.

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Measurement of optical constants of thin a-C:H films

Cited by 10 publications

References 6 publications

LO−TO Splittings in Plasma-Deposited Siloxane Films

LO−TO Splittings in Plasma-Deposited Siloxane Films

Measurement method for high-temperature infrared optical constants of ZnS crystal materials in a multi-layer structure

Process Modeling and Fabrication of Microlens Array in Thick Photoresist

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