Atomic Layer Deposition of Metal oxides

Scherer, Double-Gymid-Structured Functional Materials, Springer Theses, DOI 10.1007/978-3-319-00354-2 8, 

Despite committing a respectable amount of time to this project, we have not yet succeeded to obtain crystalline double-gyroid-structured Ti02 films. Based on the here represented results we are planing to test a homebuilt ALD which is currently under construction and was especially designed for high precursor concentrations 

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Wang, X., S.M. Tabakman, and H. Dai, Atomic layer deposition of metal oxides on pristine and functionalized graphene. Journal of the American Chemical Society, 2008.130(26) p. 8152-8153. 

Raeisaenen P.I., Ritala M., Leskelae M. Atomic layer deposition of AI2O3 films using AICI3 and Al(0 Pr)3 as precursors. J. Mater. Chem. 2002 12 1415-1418 Rahtu A., Ritala M., Leskelae M. Atomic layer deposition ofzirconium titanium oxide from titanium isopropoxide and zirconium chloride. Chem. Mater. 2001 13 1528-1532 Ritala M., Kukli K., Rahtu A., Raisanen P.I., Leskela M., Sajavaara T., Keinonen J. Atomic layer deposition of oxide thin films with metal alkoxides as oxygen sources. Science 2000 288 319-321... 

High-vacuum dry-processes, such as chemical vapor deposition (CVD) and molecular beam epitaxy (MBE), have made it feasible to control precisely the thickness of metal oxide thin films. In these techniques, the preparative conditions like pressure and substrate temperature can be widely varied, and the elemental composition in individual atomic layers is controllable by sequential supply of precursor gases [1]. The dense, defect-less oxide films thus prepared are frequently used as underlayers of microelectronics devices. 

This chapter is intended to cover major aspects of the deposition of metals and metal oxides and the growth of nanosized materials from metal enolate precursors. Included are most types of materials which have been deposited by gas-phase processes, such as chemical vapor deposition (CVD) and atomic layer deposition(ALD), or liquid-phase processes, such as spin-coating, electrochemical deposition and sol-gel techniques. Mononuclear main group, transition metal and rare earth metal complexes with diverse /3-diketonate or /3-ketoiminate ligands were used mainly as metal enolate precursors. The controlled decomposition of these compounds lead to a high variety of metal and metal oxide materials such as dense or porous thin films and nanoparticles. Based on special properties (reactivity, transparency, conductivity, magnetism etc.) a large number of applications are mentioned and discussed. Where appropriate, similarities and difference in file decomposition mechanism that are common for certain precursors will be pointed out. 

Reductive UPD is the major atomic layer deposition process used in EC-ALE to form atomic layers (Eq. 1). Many metals can be obtained in a soluble oxidized form, from which atomic layers can be deposited at underpotentials. Control points are the concentration of the reactant, the potential used for the deposition, the pH, and the presence of other additives or complexing agents, which can change the activity of the reacting species. 

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