Layer-Engineered Functional Multilayer Thin-Film Structures and Interfaces through Atomic and Molecular Layer Deposition

Atomic layer deposition (ALD) technology is one of the cornerstones of the modern microelectronics industry, where it is exploited in the fabrication of high-quality inorganic thin films with excellent precision for film thickness and conformality. Molecular layer deposition (MLD) is a counterpart of ALD for purely organic thin films. Both ALD and MLD rely on self-limiting gas-surface reactions of vaporized and sequentially pulsed precursors and are thus modular, meaning that different precursor pulsing cycles can be combined in an arbitrary manner for the growth of elaborated superstructures. This allows the fusion of different building blocks — either inorganic or organic — even with contradicting properties into a single thin-film material, to realize unforeseen material functions which can ultimately lead to novel application areas. Most importantly, many of these precisely layer-engineered materials with attractive interfacial properties are inaccessible to other synthesis/fabrication routes. In this review, the intention is to present the current state of research in the field by i) summarizing the ALD and MLD processes so far developed for the multilayer thin films, ii) highlighting the most intriguing material properties and potential application areas of these unique layer-engineered materials, and iii) outlining the future perspectives for this approach.