TiO2 sensoric structures with controlled extension of their active area by electron-beam lithography and reactive ion etching techniques

Abstract

Metal-oxide nanostructures with precisely controlled geometries can play an important role in the technological improvement of sensors for gas detection. In this article we deal with the preparation of sensoric structures of sputtered TiO2 film the aim of which is for detection of environmental gases such as COx, NOx or NH3 and the like. Thin polycrystalline TiO2 deposited on a resistive layer of SiO2 was patterned by Electron-Beam Lithography (EBL) and subsequently Reactive Ion Etching (RIE) etched to obtain controlled geometrical extension of its active area. The increase and enhancement of the TiO2 active area was also controlled by its annealing and Ion Coupled Plasma (ICP RIE) etching through a Hydrogen Silsesquioxane (HSQ) resist mask or eventually an aluminum mask.