Ab Initio Molecular Dynamics Simulation on Structure and Strength of Si/Al Interface

It is of great importance to clarify the atomic structure and strength of interfaces between metal and Si substrate in an electronic device. While interaction between atoms near the interface is complicated, ab initio molecular dynamics makes it possible to analyze such properties of interface. In this study, in order to evaluate structure and strength of Si/Al interface, evaporation process of Al atoms onto Si substrate and its tensile deformation are examined by ab initio molecular dynamics simulation. Al atoms are precipitated from above the Si(001) surface. The adhesive strength of the Al atom in the 1st layer on the surface is evaluated as 1.3nN by the tensile simulation. The 2nd layer of Al atoms are formed about 0.1nm above the 1st layer. The interval between the layers are about half of that between (111) planes in the Al single crystal lattice.