Atomic layer deposition: State-of-the-art and research/industrial perspectives

Interest on nanometric conformal coatings is currently growing across a wide range of applications, from electronic components to corrosion protection, chemical barriers or even wear decrease. Currently, atomic layer deposition (ALD) is one of the most promising nanometric deposition technologies: it offers the possibility to obtain conformal coatings even on very complex tridimensional substrates, with a strict thickness tolerance. During an ALD cycle, only one molecular layer is deposited on the substrate surface, enabling the theoretical possibility to tailor the composition of the deposit up to molecular resolution. In the fi rst part of this review, a brief history of ALD is presented to better understand the evolution of the technique during the past fi ve decades; in the second part, a short description of the main ALD techniques is given, considering their main advantages and drawbacks. In the third part, a short review about ALD applications is presented, and in the fourth part the most useful and used instruments for the analysis and characterization of ALD are listed; some results are discussed and particular emphasis on the corrosion protection of different metallic alloys of common industrial interest is given.