Deposition of titanium dioxide from TTIP by plasma enhanced and remote plasma enhanced chemical vapor deposition

Photocatalytic materials, and especially titanium dioxide, have gained wide popularity in recent years in reason of their interesting properties which can be useful in various fields of application, in particular as self-cleaning materials. When submitted to an illumination (in most cases UV-light), the surface of a photocatalytic material becomes chemically active and simultaneously displays a photo-generated hydrophilic activity (PSH effect).Classically, photocatalytic properties are displayed by crystalline titanium dioxide. In this paper we detail the chemical vapor deposition of TiO2 carried out in two experimental set-ups: one is plasma enhanced reactor and the other is remote plasma enhanced reactor. Both experiments were carried out with titanium(IV) isopropoxide (TTIP). Titanium(IV) tetrachloride (TiCl4) and titanium(IV) ethoxide (TEOT) were also used in the first setup.In RF-diode plasma reactor, titanium dioxide films were deposited in amorphous form and crystallization of amorphous films was obtained with the help of thermal post-treatments, since seeding and under-layers appeared unable to trigger the crystallization of films. In the remote plasma CVD reactor, allowing high plasma density and ion energy, deposition of crystalline anatase titanium dioxide was achieved at a deposition temperature of 400 °C.Conclusions are presented and suggest control mechanisms for the stoichiometry of titanium dioxide films.