Atomic Layer Deposition of Al2O3 onto Sn-Doped In2O3: Absence of Self-Limited Adsorption during Initial Growth by Oxygen Diffusion from the Substrate and Ba

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• 作者：Thorsten J.M. Bayer ; Andr茅 Wachau ; Anne Fuchs ; Jonas Deuermeier ; Andreas Klein
• 刊名：Chemistry of Materials
• 出版年：2012
• 出版时间：December 11, 2012
• 年：2012
• 卷：24
• 期：23
• 页码：4503-4510
• 全文大小：372K
• 年卷期：v.24,no.23(December 11, 2012)
• ISSN：1520-5002

文摘

The growth of Al₂O₃ onto Sn-doped In₂O₃ (ITO) by atomic layer deposition (ALD) was studied in situ using X-ray photoelectron spectroscopy. Significant diffusion of oxygen from the substrate destroys the self-terminated monolayer adsorption of the metal precursor and results in a nominal initial growth per cycle of >1 nm. The observed mechanism precludes the preparation of monolayer thick Al₂O₃ films on ITO substrates by ALD. The energy band alignment at the ITO/Al₂O₃ interface is significantly different from that obtained when magnetron sputtering is used for the deposition of Al₂O₃ onto ITO [Gassenbauer et al., Phys. Chem. Chem. Phys.2009, 11, 3049]. The difference is attributed to a pinning of the Fermi level in the ALD-Al₂O₃ layer close to midgap, which is attributed to the incorporation of hydrogen in the film during growth.

Keywords:

indium鈭抰in oxide; AL₂O₃; atomic layer deposition; initial growth; interface properties; band alignment; hydrogen impurity