Micro-nanostructuring by optical lithography and nitridation of photo-patternable TiO2 sol-gel to obtain micro-nanostructured TiN

Titanium nitride (TiN) combines plasmonic properties in the visible and near infrared spectral region with good mechanical properties, high thermal and chemical stability making it a very promising alternative to noble metals for optical applications at high temperature or in extreme environments. The most common processes for the fabrication of TiN coatings are chemical and physical vapor deposition. Unfortunately, due to their good hardness and chemical resistance, TiN layers are very difficult to microstructure directly after deposition. Another method of deposition TiN film is the nitridation of a titanium oxide (TiO2) layer. It consists in heating the TiO2 at more than 800 degrees C for several hours under ammonia gas. At this temperature TiO2 layer will react with ammonia forming a TiN film. The authors present a new easy and fast process for the elaboration of micro-nanostructured TiN layers from a photo-patternable TiO2 sol-gel and a nitridation process, by rapid thermal annealing (RTA). This sol-gel is photo-patternable by optical lithography, it allows to easily and quickly produce patterned TiO2 layers. Afterwards, micro-nanostructured TiO2 is converted into micro-nanostructured TiN in a few minutes by RTA process under ammonia gas. This presentation will introduce this new process. Preliminary results will be presented through several microstructured TiN demonstrators obtained from the microstructuring process based on TiO2 sol-gel layers. The produced layers have been characterized by X-ray diffraction, (Scanning) Transmission Electron Microscopy, Raman spectroscopy.. The optical properties have also been investigated and the stability of TiN films over time will be presented.