Structural and ellipsometric study on tailored optical properties of tantalum oxynitride films deposited by reactive sputtering - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Physics D: Applied Physics Année : 2014

Structural and ellipsometric study on tailored optical properties of tantalum oxynitride films deposited by reactive sputtering

Résumé

Oxynitride materials, which offer the possibility of merging oxide and nitride properties, are increasingly studied for this reason. This paper focuses on assessing the optical properties of tantalum oxynitride thin films deposited by pure tantalum target sputtering in an Ar/O2/N2 reactive atmosphere. First, by changing the oxygen to reactive gas flow rate ratio, and using thermal post-treatment, we deposited films with elemental compositions studied by Rutherford backscattering spectroscopy, ranging from a nitride (close to Ta3N5) to an oxide (close to Ta2O5) with various structures analyzed by x-ray diffraction. Their optical properties were investigated in depth by spectroscopic ellipsometry and UV-visible spectroscopy. For the ellipsometry investigation, we propose a model combining the Tauc–Lorentz law and additional Lorentz oscillator: the first contribution is linked to a semi-conductor or insulator film matrix, and the second one to the presence of conductive TaN crystals. Ellipsometry thus appears as a powerful tool to investigate complex materials such as tantalum oxynitrides. Moreover, we demonstrated that using this deposition method we were able to finely tune the film refractive index from 3.4 to 2.0 (at 1.96 eV) and the optical band gap, specifically from 1.3 to 2.7 eV.

Domaines

Chimie
Fichier non déposé

Dates et versions

hal-01080842 , version 1 (06-11-2014)

Identifiants

Citer

Angélique Bousquet, Fadi Zoubian, Joël Cellier, Christine Taviot-Gueho, Thierry Sauvage, et al.. Structural and ellipsometric study on tailored optical properties of tantalum oxynitride films deposited by reactive sputtering. Journal of Physics D: Applied Physics, 2014, 47, pp.475201. ⟨10.1088/0022-3727/47/47/475201⟩. ⟨hal-01080842⟩
92 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More