Room temperature growth of ultra porous hot-wire deposited tantalum pentoxide

¹Institute of Nanoscience and Nanotechnology, NCSR Demokritos POB 60228, Agia Paraskevi, Attiki, 153 10, Greece

²Department of Chemical Engineering, University of Patras, Patra, 26500, Greece

Adv. Mater. Lett., 2019, 10 (6), pp 395-399

DOI: 10.5185/amlett.2019.2283

Publication Date (Web): Jan 14, 2019

Copyright © IAAM-VBRI Press

E-mail: g.papadimitropoulos@inn.demokritos.gr

Abstract

Tantalum pentoxide films were deposited on Si substrates at room temperature, by heating metallic filaments at temperatures below 600 ^oC, at a pressure of 1 Torr in O₂ environment. This deposition method can be applied for all metallic oxides having higher vapor pressure than the corresponding metal. These (hwTa₂O₅) films were composed by amorphous material (as revealed by XRD measurements) and were found to be highly transparent within the range 350-1000 nm. Spectroscopic ellipsometry measurements have shown that the real part of the refractive index (n) of hwTa₂O₅ films depends on the deposition time and has a value below 1.5. As shown by scanning electron microscopy (TEM) measurements, these grains were composed by others with dimensions near 5 nm and with voids between them. The above microscopy measurements explain the high porosity of hwTa2O5 films. Moreover, hwTa₂O₅ films were also characterized by XPS and UPS measurements and the stoichiometric composition of the deposited films was determined.

Keywords

Thin film, hot-wire deposition, tantalum pentoxide, room temperature growth.