1. Atomic Layer Deposition, Characterization, and Growth Mechanistic Studies of TiO2 Thin Films
- Author
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Mikko Kaipio, Marco Gavagnin, V Valentino Longo, Christian Dussarrat, Jaakko Niinistö, Esa Puukilainen, Yoann Tomczak, Mikko Ritala, Heinz Dr. Wanzenböck, Venkateswara R. Pallem, Markku Leskelä, and Timothee Blanquart
- Subjects
010302 applied physics ,Anatase ,Materials science ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,Surfaces and Interfaces ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,chemistry.chemical_compound ,Atomic layer deposition ,chemistry ,X-ray photoelectron spectroscopy ,Rutile ,0103 physical sciences ,Titanium dioxide ,Electrochemistry ,Physical chemistry ,General Materials Science ,Thin film ,0210 nano-technology ,Spectroscopy ,Titanium - Abstract
Two heteroleptic titanium precursors were investigated for the atomic layer deposition (ALD) of titanium dioxide using ozone as the oxygen source. The precursors, titanium (N,N'-diisopropylacetamidinate)tris(isopropoxide) (Ti(O(i)Pr)3(N(i)Pr-Me-amd)) and titanium bis(dimethylamide)bis(isopropoxide) (Ti(NMe2)2(O(i)Pr)2), exhibit self-limiting growth behavior up to a maximum temperature of 325 °C. Ti(NMe2)2(O(i)Pr)2 displays an excellent growth rate of 0.9 Å/cycle at 325 °C while the growth rate of Ti(O(i)Pr)3(N(i)Pr-Me-amd) is 0.3 Å/cycle at the same temperature. In the temperature range of 275-325 °C, both precursors deposit titanium dioxide in the anatase phase. In the case of Ti(NMe2)2(O(i)Pr)2, high-temperature X-ray diffraction (HTXRD) studies reveal a thickness-dependent phase change from anatase to rutile at 875-975 °C. X-ray photoelectron spectroscopy (XPS) indicates that the films have high purity and are close to the stoichiometric composition. Reaction mechanisms taking place during the ALD process were studied in situ with quadrupole mass spectrometry (QMS) and quartz crystal microbalance (QCM).
- Published
- 2014
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