Atomic Layer Deposition, Characterization, and Growth Mechanistic Studies of TiO2 Thin Films

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• 作者：Mikko Kaipio ; Timothee Blanquart ; Yoann Tomczak ; Jaakko Niinist枚 ; Marco Gavagnin ; Valentino Longo ; Heinz D. Wanzenb枚ck ; Venkateswara R. Pallem ; Christian Dussarrat ; Esa Puukilainen ; Mikko Ritala ; Markku Leskel盲
• 刊名：Langmuir
• 出版年：2014
• 出版时间：July 1, 2014
• 年：2014
• 卷：30
• 期：25
• 页码：7395-7404
• 全文大小：478K
• ISSN：1520-5827

文摘

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鈥?diisopropylacetamidinate)tris(isopropoxide) (Ti(OⁱPr)₃(NⁱPr-Me-amd)) and titanium bis(dimethylamide)bis(isopropoxide) (Ti(NMe₂)₂(OⁱPr)₂), exhibit self-limiting growth behavior up to a maximum temperature of 325 掳C. Ti(NMe₂)₂(OⁱPr)₂ displays an excellent growth rate of 0.9 脜/cycle at 325 掳C while the growth rate of Ti(OⁱPr)₃(NⁱPr-Me-amd) is 0.3 脜/cycle at the same temperature. In the temperature range of 275鈥?25 掳C, both precursors deposit titanium dioxide in the anatase phase. In the case of Ti(NMe₂)₂(OⁱPr)₂, high-temperature X-ray diffraction (HTXRD) studies reveal a thickness-dependent phase change from anatase to rutile at 875鈥?75 掳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).