In Situ Reaction Mechanism Studies on the New tBuN=M(NEt2)3 -Water and tBuN=M(NEt2)3 - Ozone (M = Nb,Ta) Atomic Layer Depositio

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• 作者：Yoann Tomczak ; Kjell Knapas ; Markku Sundberg ; Markku Leskel盲 ; Mikko Ritala
• 刊名：Chemistry of Materials
• 出版年：2012
• 出版时间：May 8, 2012
• 年：2012
• 卷：24
• 期：9
• 页码：1555-1561
• 全文大小：349K
• 年卷期：v.24,no.9(May 8, 2012)
• ISSN：1520-5002

文摘

In this work, quartz crystal microbalance (QCM) and quadrupole mass spectrometry (QMS) have been used for in situ investigations of the D₂O and ozone processes at 250 掳C for ^tBuN=Nb(NEt₂)₃ and ^tBuN=Ta(NEt₂)₃. In the D₂O processes, the ligand exchange reaction is demonstrated by the formation of D₂N^tBu and DNEt₂ as byproduct. For ^tBuN=Nb(NEt₂)₃, one out of three -NEt₂ ligands is exchanged during the precursor pulse, whereas for ^tBuN=Ta(NEt₂)₃, it is 1.7 -NEt₂ ligands and 0.3 =N^tBu ligand that are exchanged during the ^tBuN=Ta(NEt₂)₃ pulse. This difference in the reaction mechanism of the two structurally similar precursors can be explained by the differences in their bond polarities as shown by our quantum chemical calculations. Regarding the ozone processes, QCM results point to a molecular adsorption of ^tBuN=Nb(NEt₂)₃ and an exchange of at least two ligands for ^tBuN=Ta(NEt₂)₃. QMS indicates a typical ozone combustion byproduct, such as CO₂ (m/z = 44), CO (m/z = 28), H₂O (m/z = 18), and NO (m/z = 30) or N₂O (m/z = 44, 30). A major fragment of both types of ligands (m/z = 58) is also observed. Precise quantification of these byproduct is rendered impossible due to overlapping of different species with the same m/z value. However, careful examination of the data reveals general information on the different contributions to the signal.

Keywords:

atomic layer deposition (ALD); mass spectrometry; quartz crystal microbalance (QCM); niobium oxide; tantalum oxide