Development and application of vapor deposition technology in atomic manufacturing

With the development of future information devices towards smaller size, lower power consumption and higher performance, the size of materials used to build devices will be further reduced. Traditional “top-down” technology has encountered a bottleneck in the development of information devices on a nanoscale, while the vapor deposition technology has attracted great attention due to its ability to construct nanostructures on an atomic scale, and is considered to have the most potential to break through the existing manufacturing limits and build nano-structures directly with atoms as a “bottom-up” method. During molecular beam epitaxy, atoms and molecules of materials are deposited on the surface in an “atomic spray painting” way. By such a method, some graphene-like two-dimensional materials (e.g., silicene, germanene, stanene, borophene) have been fabricated with high quality and show many novel electronic properties, and the ultrathin films (several atomic layers) of other materials have been grown to achieve certain purposes, such as NaCl ultrathin layers for decoupling the interaction of metal substrate with the adsorbate. In an atomic layer deposition process, which can be regarded as a special modification of chemical vapor deposition, the film growth takes place in a cyclic manner. The self- limited chemical reactions are employed to insure that only one monolayer of precursor (A) molecules is adsorbed on the surface, and the subsequent self- limited reaction with the other precursor (B) allows only one monolayer of AB materials to be built. And the self- assembled monolayers composed of usually long- chain molecules can be introduced as the active or inactive layer for area- selective atomic layer deposition growth, which is very useful in fabricating nano- patterned structures. As the reverse process of atomic layer deposition, atomic-layer etching processes can remove certain materials in atomic precision. In this paper we briefly introduce the principles of the related technologies and their applications in the field of nano- electronic device processing and manufacturing, and find how to realize the precise control of the thickness and microstructure of functional materials on an atomic scale.