Micro-nanostructured plasmonic TiN layer produced using rapid thermal nitridation of a nanoimprinted TiO₂ sol-gel

Abstract

Titanium nitride (TiN) is a very promising new plasmonic material to replace traditional plasmonic materials like gold and silver, especially thanks to its thermal and chemical stability. However, its chemical resistance and its hardness make TiN difficult to microstructure. An alternative approach is to micro-nanostructure a titanium dioxide (TiO2) coating and then to use a nitridation reaction to obtain a micro-nanostructured TiN coating. This is an easy, rapid and cost-effective structuring process. In this paper, we demonstrate that rapid thermal nitridation (RTN) can be combined with nanoimprint lithography (NIL) to rapidly micro-nanostructure a TiN layer. This innovative approach is applied to a micro-nanostructured TiN layer for plasmonic response in the near infrared range. Experimental and theoretical approaches are compared.

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

“…A recent method has been proposed from a complete sol-gel process. It involves TiO2 sol-gel film that can be first photo-patterned and converted into TiN using thermal nitridation in an ammonia atmosphere [22][23][24][25][26] . The main benefit of using a sol-gel based process is the ability to produce submicron structures with various reproducible shapes, such as gratings 22,27, or pillars [28][29][30][31] , on large surface areas 28 without shape restrictions 32,33 .…”

Micro-nanostructuring of ZrO2 sol-gel by optical and nanoimprint lithography on various substrate for optical applications

“…Another option for producing ZrO2 thin films is the sol-gel method [26][27][28][29][30][31] . The sol-gel method allows the micro-nanostructuring of thin films through techniques such as optical 29,[31][32][33][34] and nanoimprint lithography [35][36][37] . Optical lithography has the advantage of being able to micro-nanostructure a wide range of substrates of different shapes 29,30,38 and sizes 39,40 without the need for etching processes.…”

“…This can be achieved through masking lithography, which uses a mask to expose a pattern, or colloidal lithography, which utilizes silica nano-spheres to create photonic nanojets that enhance the incident field and enables thin film micro-structuring. Nanoimprint lithography (NIL) is an other method that involves a stamp which is pressed onto a layer to create a pattern 36,41,42 . This method is fast, low-cost, and can be used on a wide range of substrates and patterns, but it requires a sol-gel solution that can be stabilized by thermal or UV treatment.…”

Innovative Process to Obtain Thin Films and Micro-Nanostructured Zrn Films from a Photo-Structurable Zro2 Sol-Gel Using Rapid Thermal Nitridation

“…In the current state of the art, nitridation of ZrN requires a long reaction time at high temperature with a reductant. In previous studies, we succeeded in obtaining obtain titanium nitride (TiN) thin film using an innovative Rapid Thermal Nitridation (RTN) technique with ammonia gas and a titanium oxide (TiO 2 ) photo-structurable sol-gel [22][23][24]. In this paper, we present a new RTN process that produces ZrN from a ZrO 2 photo-structurable sol-gel by nitridation with ammonia gas.…”