PECVD of amorphous TiO2 thin films: effect of growth temperature and plasma gas composition

Amorphous TiO2 thin films are grown using a r.f. plasma-enhanced chemical v apour deposition process at substrate temperatures between 393 and 523 K us ing titanium tetraisopropoxide as a precursor, and Ar or N-2, pure or mixed with O-2, as the plasma gas. All films are smooth and adherent, their roug hness slightly increases by increasing the substrate temperature or if oxyg en is added to the plasma gas. Films grown in the presence of oxygen result transparent in the visible region and highly resistive, as expected for pu re titanium dioxide. Films grown in an oxygen-free plasma appear grey-blue and fairly conductive suggesting the presence of Ti(III) species. The opera ting conditions provide high deposition rates, up to 37 nm/min in the prese nce of oxygen. (C) 2000 Elsevier Science S.A. All rights reserved.