Self-Limiting Deposition of Anatase TiO2 at Low Temperature by Pulsed PECVD

The self-limiting deposition of anatase TiO2 was accomplished by pulsed plasma-enhanced chemical vapor deposition (PECVD) using a simultaneous delivery of TiCl4 and O-2. The amorphous to anatase phase transition was examined as a function of temperature, plasma power, and film thickness. Films deposited at T=120 degrees C, with the plasma power set at 100 W were amorphous, containing residual amounts of chlorine. At 200 W, the films displayed an anatase structure, and no chlorine was detected by X-ray photoelectron spectroscopy. Spectroscopic ellipsometry, Fourier transform infrared, and X-ray diffraction measurements concur that a minimum film thickness of similar to 25 nm is required for the formation of the anatase phase.