Kaipio Mikko, Blanquart Timothee, Tomczak Yoann, Niinistö Jaakko, Gavagnin Marco, Longo Valentino, Wanzenböck Heinz D, Pallem Venkateswara R, Dussarrat Christian, Puukilainen Esa, Ritala Mikko, Leskelä Markku
Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki , P.O. Box 55, FI-00014 Helsinki, Finland.
Langmuir. 2014 Jul 1;30(25):7395-404. doi: 10.1021/la500893u. Epub 2014 Jun 18.
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).
研究了两种杂配钛前驱体用于以臭氧作为氧源的二氧化钛原子层沉积（ALD）。前驱体，三异丙醇钛（N，N'-二异丙基乙酰胺）（Ti(O(i)Pr)3(N(i)Pr-Me-amd)）和双（二甲基酰胺）双异丙醇钛（Ti(NMe2)2(O(i)Pr)2），在高达325℃的最高温度下表现出自限性生长行为。Ti(NMe2)2(O(i)Pr)2在325℃时显示出0.9 Å/循环的优异生长速率，而Ti(O(i)Pr)3(N(i)Pr-Me-amd)在相同温度下的生长速率为0.3 Å/循环。在275 - 325℃的温度范围内，两种前驱体都沉积锐钛矿相的二氧化钛。对于Ti(NMe2)2(O(i)Pr)2，高温X射线衍射（HTXRD）研究表明在875 - 975℃存在从锐钛矿到金红石的厚度依赖性相变。X射线光电子能谱（XPS）表明薄膜具有高纯度且接近化学计量组成。利用四极杆质谱（QMS）和石英晶体微天平（QCM）对ALD过程中发生的反应机理进行了原位研究。
