Versatile Micro and Nano Patterning Technique for TiO2 and TiN-Based Sol-Gel Thin Films

This paper describes a tailored and versatile technology route to achieve micro and nanopatterning of both TiO2 and TiN thin films using a direct photo patternable sol-gel approach combined with a rapid thermal annealing and nitridation process. The approach consists in multi-scale structuring TiO2 using laser direct writing or mask/colloidal lithography on a wide range of substrates including materials and of diverse geometry. These patterned TiO2 layers can subsequently be converted into a micro-structured metallic TiN layer using a direct rapid thermal nitridation process that results in metallic thin films (TiN). This work demonstrates the versatility of this complete chain of soft chemistry based new process for patterning TiO2 and TiN thin films thereby avoiding expensive processes such as etching and lift-off, while preserving their diffractive properties and high thermal stability, that is, up to 1000 degrees C under vacuum. The process is compatible with different kinds of substrates of different shapes and sizes. These results pave the way for developing a cost-effective and time-saving approach to different cutting-edge applications such as metasurfaces, sensors, and applications in the luxury and decoration sector.