Physical deposition of atomic layers and growth of extremely thin films: four-decade series of the refractory metal-silicon system studies

The article is devoted to the author's four-decade series of studies on growing extremely thin films (ETF) in the refractory metal-silicon system. To obtain ETF, it was necessary to develop a new growth method — physical atomic-layer deposition (PALD), which uses the technique of pulsed evaporation of adsorbate from a flat source located parallel to the substrate. Compared to the traditional molecular beam deposition (MBE) method, PALD reduces the vapor temperature, produces thinner layers, and expands the range of materials produced. The study showed that, with PALD using reduced substrate and vapor temperatures, not only two-dimensional surface phases (2D-SP) can form, but also two-dimensional (2D-SWL) and, subsequently, nanophase (ν-SWL) wetting layers (SWL). The series investigated the growth of ETFs Cr, Co, Fe, Cu and their silicides on Si (111) and Si (001), as well as the growth of Si on Si (111)7×7 and CrSi₂ (0001). Single-layer and multilayer (Co-Cu-Fe-Cu) nanofilms were obtained. The main causes of phase transitions in SWL have been identified, and the role of vapor pressure and substrate temperatures in the structure and composition of SWL and the boundary layer of the substrate has been shown. The study showed that the films obtained by the PALD method have unique electrical, optical and magnetic properties and are promising for use in micro- and nanoelectronics nanodevices.