Molecular dynamics simulations of Al-Cu thin film growth processes

Abstract

MD simulation is a powerful tool to interpret the thin film growth behavior by deposition process, which is widely used in semiconductor industry for last few decades. Among the several thin film growth behaviors, Al and Cu deposition process are needed to be understood for further applications in semiconductor industry. In order to understand the mechanism of Al and Cu deposition process, the atoms with various kinds of energy were deposited on substrate in order to calculate the efficiency of deposition using by ion bombardment. The threshold energy of sputtering is about 25eV and most of atoms would be deposited on substrate without sputtering because most atoms have less energy than 20eV. The intermixing behaviors between Al atoms on Cu substrate atoms and the reverse case were observed. This is due to different characteristic of Al and Cu. To investigate the key factors determining intermixing behavior, many deposition processes were executed at various conditions, such as various incident energy, various substrate temperature and substrate orientation. The information about the dynamics of the deposition process was obtained by tracing the evolution of atoms with time. This simulation procedure proved the layers do not grow layer-by-layer. Considering these results, experimental data of Cu/Al/Cu trilayer was used to reproduce. To reduce the gap between experiment and simulation, flawed substrate was made by same atoms deposition process. These results are coincident with experimental data and the intermixing length was increased and more atoms penetrate into substrate. Annealing process was adapted to prevent the intermixing behavior between Al atoms and Cu substrate atoms and the reverse case. In this thesis, the Al and Cu deposition mechanism are studied and compared with experimental result. The simulation results of Al and Cu deposition were well matched with experimental results. Based on these simulation results, MD simulation is one of th...