Growth, characterization and processing of VO2 thin films for micro-switching devices

摘要

Single-phase vanadium-dioxide (VO2) thin films have been deposited on various substrates by means of a reactive pulsed-laser-deposition technique. While the preferred orientation is (011) monoclinic for the films deposited on silicon substrates and (020) monoclinic for those deposited on sapphire substrates, the thermochromic properties of the VO2 layers is found to be fairly independent of the substrate type. It is further shown that W doping and Ti-W co-doping significantly improve the thermochromic properties. Following growth, VO2 layers were used in the context of the development of micro-switching devices. For this purpose, patterning of the VO2 layers was investigated using a high-density argon magnetoplasma. Highly anisotropic features have been produced with a high etch rate and a good selectivity over resist. The etch rate for VO2/AI2O3 samples is found to be higher than that for VO2/Si samples, which is due to the higher number of surface dangling bonds in the (020) phase as compared to the (011) phase.