Beiträge zur Chemie flüchtiger Metallverbindungen für die chemische Gasphasenabscheidung: Hydrazin-basierte N-Donor-Liganden und neue Synthesestrategien

The aim of this thesis was the syntheses of highly volatile molecules for potential application as precursors in chemical vapour deposition processes to generate thin films of elements or element nitrides. Besides moderate thermal stability, the developed compounds should exhibit a high volatility and a low vapour phase decomposition temperature. By designing appropriate ligand systems the characteristics of the novel complexes are attempted to be controlled in a way that they have a low melting temperature, ideally being liquid at room temperature. Within this work a large number of nitrogen rich complexes based on tert-butylhydrazine, N-amino-amidinato- and guanidinato- as well as N,N'-dialkylated triazenido-ligands was investigated. It was shown that the variation of the ligand backbone has a strong influence on the thermal behavior. The hydrazine unit as a predetermined breaking point for thermal decomposition at low temperatures in combination with reducing equivalents leads to the elemental metal as deposition product. Moreover new synthesis strategies of established precursors for chemical vapour deposition processes within industry-related and application-oriented research were developed. Besides technically attractive synthetic routes to tungsten(VI)-oxo-alkoxides and tungsten(VI)-amido-amides, different substituted aluminates were investigated as transfer reagents. With the help of these substituted aluminium metallates it was possible to transfer dimethylamido groups to refractory metal chlorides. Furthermore the established phosphorus source for chemical vapour deposition processes tert-butylphosphine was synthesized in a technically attractive one-pot synthesis in a high yield. This thesis represents the combination of fundamental research to develop potential precursor molecules and technologically research for established precursors.