| AVS 56th International Symposium & Exhibition | |
| Thin Film | Tuesday Sessions |
| Session TF2-TuA |
| Session: | ALD/CVD: Oxides and Barriers |
| Presenter: | N.G. Kubala, Colorado School of Mines |
| Authors: | N.G. Kubala, Colorado School of Mines C.A. Wolden, Colorado School of Mines |
| Correspondent: | Click to Email |
Titanium dioxide thin films were deposited using pulsed plasma-enhanced chemical vapor deposition at low temperature (Ts <200 ºC). Self-limiting deposition (~1 Å/cycle) was accomplished via simultaneous delivery of TiCl4 and O2. TiCl4 is shown to be inert with molecular oxygen at process conditions, making it a suitable precursor for pulsed PECVD. The process was examined as a function of TiCl4 exposure, plasma power, and substrate temperature. Crystalline anatase formation was observed at temperatures as low as 120oC. Depositions at high power also had a significantly greater refractive index. For process conditions, digital control over film thickness is demonstrated. Film uniformity is exceptional, with thickness variations less than 1% across 100 mm silicon wafers. Photocatalytic activity has been examined using methylene blue decomposition experiments, UV-VIS spectroscopy, and electrochemical analysis. Mott-Schottky plots show that the band edge position of these thin films is in agreement with measurements from anatase single crystals. The photocatalytic activity of these films for both hydrogen production and organic remediation is assessed. We also plan to present new results on the production of the titania-vanadia alloys with enhanced light response in the visible regime.