On adsorption of aluminium and methyl groups on silica for TMA/H2O process in atomic layer deposition of aluminium oxide nano layers

Bulletin of Materials Science - Tập 33 - Trang 97-102 - 2010
Anu Philip1, K. Rajeev Kumar1
1Department of Instrumentation, Cochin University of Science and Technology, Cochin, India

Tóm tắt

A detailed chemisorption mechanism is proposed for the atomic layer deposition (ALD) of aluminium oxide nano layers using trimethyl aluminum (TMA) and water as precursors. Six possible chemisorption mechanisms, complete ligand exchange, partial ligand exchange, simple dissociation, complete dissociation via ligand exchange, complete dissociation and association, are proposed and related parameters like ligand to metal ratio (L/M), concentrations of metal atoms and methyl groups adsorbed are calculated and compared against reported values. The maximum number of methyl groups that can get attached on the surface is calculated in a different way which yields a more realistic value of 6·25 per nm2 substrate area. The dependence of the number of metal atoms adsorbed on OH concentration is explained clearly. It is proposed that a combination of complete ligand exchange and complete dissociation is the most probable chemisorption mechanism taking place at various OH concentrations.

Tài liệu tham khảo

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