Ion impingement effect on the structure and optical properties of Ti_xSi_1−xO₂ films deposited by ICP‐PECVD

Abstract

TixSi1−xO2 films are grown by plasma‐enhanced chemical vapor deposition from oxygen‐rich O2/titanium tetraisopropoxide/hexamethyldisiloxane radiofrequency inductively coupled plasmas at low pressure. By applying a substrate bias of −50 V, the ion energy is increased from 15 to 75 eV, which has almost no effect on the by‐products, whereas the deposition rate is decreased and the Ti/Si atomic ratio in the film is increased. For the lowest hexamethyldisiloxane fraction in precursor, applying a −50 V bias leads to the formation of TiO2 in rutile phase in the film. The film optical properties (optical index and band gap) are shown to be mainly governed by the film chemical composition.

Unravelling local environments in mixed TiO2–SiO2 thin films by XPS and ab initio calculations

“…Considering how the model was constructed, one is of course curious what is the thermodynamic temperature T corresponding to the observed disorder. An estimate of E is necessary, which can be obtained by fitting the formation energy dependencies on composition [30] by formula (9). For the amorphous phase, which is probably the most relevant, we obtain E 0.17 eV, giving T 2400 K. Although this temperature may seem high at the first sight, it is consistent with similar approaches also considering only configurational entropy.…”

“…The mixed oxides serve as base components for complex nanomaterials with applications in photoluminescence [4], electrochemical sensors [5] or catalytic hydrogenation [6] dehydrogenation [7] and hydrodeoxygenation [8]. There are also multiple possible optical application for those coatings [9], with demonstrated use in waveguides [10,11], laser mirrors [12] and rugate filters [13].…”