Structure and electric properties of TiO2 films prepared by cold plasma torch under atmospheric pressure

A torch-like plasma generator we developed to make low temperature material processing possible in open air conditions was employed lor the deposition of TiO2 films on substrates exposed to air. Ti(OEt)4 or Ti(O-iPr)4 vapor was fed into the plasma generated in an insulator nozzle lining the inner surface of a grounded cylindrical anode and containing a metal needle cathode at the center. The homogeneous plasma with Tc of 1.8 eV and Tg of 2()0 °C. respectively, could decompose Ti(OR)4 to flush decomposition species onto a substrate placed in air. The film thus prepared was stoichiometric and amorphous TiO2, but contained short-range crystallinity. The phase structure of the films changed by the admixing of hydrogen in the plasma. The TiO2 film deposited from a TEOT H2 mixture had a high breakdown electric field (1.2 MV cm −1) as well as a high dielectric constant (ɛ= 54) even in amorphous phase.