Synthetic and Spectroscopic Study of the Mechanism of Atomic Layer Deposition of Tin Dioxide

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• 作者：Matthew S. Weimer ; Bo Hu ; Steven J. Kraft ; Roy G. Gordon ; Carlo U. Segre ; Adam S. Hock
• 刊名：Organometallics
• 出版年：2016
• 出版时间：May 9, 2016
• 年：2016
• 卷：35
• 期：9
• 页码：1202-1208
• 全文大小：378K
• 年卷期：0
• ISSN：1520-6041

文摘

This study details the surface reaction chemistry relevant to the vapor deposition mechanism of SnOub>2ub> thin films by atomic layer deposition. The mechanism was elucidated by combining different spectroscopic studies. Initial nucleation of cyclic Nup>2up>,Nup>3up>-di-tert-butylbutane-2,3-diamidotin(II) (1) consists of surface SiOH protonation of ligands as shown by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). This SiOub>2ub>-surface-bound stannylene was further characterized by X-ray absorption (XAS) and resonance Raman spectroscopy. XAS, DRIFTS, and Raman spectroscopy were then used to follow the further reaction of the surface-bound stannylene with different oxygen sources and a second equivalent of 1. It was observed that water does not oxidize the initial surface-bound tin site, and a well-defined, three-coordinate tin(II) species, with two surface oxygen bonds and one coordinated water molecule, was characterized. Treatment of the surface stannylene with protic oxidants such as Hub>2ub>Oub>2ub> or tBuOOH fully oxidizes tin to 4+, and coordination of additional oxygen ligands is observed. When a second equivalent of 1 is added to surface-bound Snup>4+up>, the resulting surface tin is also found to be in the 4+ oxidation state, contrary to the nonoxidative nucleation step. As such, surface peroxide species provide a probable growth mechanism of SnOub>2ub> through oxidation, while nucleation occurs through protic ligand exchange.