Al-Si/AlN nanomultilayered systems with reduced melting point: Experiments and simulations

Abstract The melting behavior of Al Si nanolayers with two different thicknesses (4 and 6 nm) confined by thin AlN layers (thickness: 3 nm) was investigated experimentally and simulated using molecular dynamics. The experimental study showed a noticeable decrease in the melting temperature of both systems, resulting in the presence of Si-enriched Al Si protrusions on the free nanomultilayer surface, forming at temperatures of T ≥ 673 K for 4 nm and T ≥ 723 K for 6 nm Al Si nanolayers, respectively. To study the mechanism of melting, as well as to explain the experimental observations, molecular dynamics simulations were performed. These revealed that silicon plays a great role in the melting process (melting always starts at the Al/Si interface and is strictly controlled by the diffusion of silicon atoms). Based on calculated non-equilibrium concentration of Si in melted Al Si nanolayers, the phase diagram for confined Al Si nanolayers was derived. Also, a mechanism of liquid outflow was proposed to explain the localized character of the melting observed experimentally.