2. Molecular engineering of ALD precursors

Combining volatility, thermal stability and reactivity in a single molecule is a real challenge, as it depends on the molecule's three-dimensional structure and the strength of intra- (chemical bonds) and intermolecular (hydrogen or van der Waals-type) interactions. This structure/properties linkage of molecular precursors for ALD must therefore take into account the various atomic parameters of the metal (radius, charge, degree of oxidation) and those of the ligand, such as its steric hindrance, the presence of fluorine atoms, its asymmetry and/or its electronic properties (donor or acceptor).

Finding the most appropriate coordination sphere for efficient ALD deposition is a field of research that has been addressed since the 1990s by several major international groups and/or prestigious world universities, most often in connection with the microelectronics industry....