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Li, D., Zhang, W. & Goullet, A. (2020) Influence of PECVD-TiO2 film morphology and topography on the spectroscopic ellipsometry data fitting process. Mod. Phys. Lett. B, 34 2050228.
Added by: Richard Baschera (2020-11-17 13:20:20) Last edited by: Richard Baschera (2020-11-17 13:25:28) |
| Type de référence: Article DOI: 10.1142/S0217984920502280 Numéro d'identification (ISBN etc.): 0217-9849, 1793-6640 Clé BibTeX: Li2020 Voir tous les détails bibliographiques  |
Catégories: INTERNATIONAL, PCM Créateurs: Goullet, Li, Zhang Collection: Mod. Phys. Lett. B |
Consultations : 1/707
Indice de consultation : 11% Indice de popularité : 2.75% |
| Liens URLs https://www.worlds ... /S0217984920502280 |
| Résumé |
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TiO 2 films of different thickness are deposited on silicon substrate at low temperature and pressure by a Helicon-PECVD reactor. The evolution of film morphology and topography is observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), meanwhile the spectroscopic ellipsometry (SE) measurements are performed to investigate the film growth mechanism and optical constants. The SEM and AFM observations show that all the films exhibit a columnar structure, moreover all the columns are vertical grown and well-organized when the thickness below [Formula: see text][Formula: see text]80 nm. As the thickness is increased to [Formula: see text][Formula: see text]150 nm, 250 nm and 450 nm, the column size is increased in the top layers, the whole film morphology becomes inhomogeneous, which leads to a decreased density and rougher surface. By fitting the SE measurements, a suitable gradient physical model is found to describe the film morphologies, the model consists of a native SiO 2 layer on Si substrate, a mediate layer mixed TiO 2 with void whose concentration gradient changed from bottom to top, and a top roughness layer. For thick films ([Formula: see text][Formula: see text]450 nm), the absorption and scattering on the rough surface is considered in order to keep the precision of SE fits. It is found that the optical index is decreased with film thickness, which is related to the evolution of structure in the top layers.
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