Modelling of the interface evolution during Si layer growth on a partially masked substrate

High-quality thin Si layers obtained from the solution by epitaxial lateral overgrowth (ELO) can play a crucial role in photovoltaic applications. The laterally overgrown parts of the layer are characterized by a lower dislocation density than that of the substrate. The height and width of the layer depend on several factors, such as the technological conditions of liquid phase expitaxy (LPE), growth temperature, cooling rate and the geometry of the system (mask filling factor). Therefore, it is crucial to find the optimal set of technological parameters in order to obtain very thin structures with a maximum width (high aspect ratio). This paper presents a computational study of Si epilayer growth on a line-pattern masked silicon substrate from Si-Sn rich solution. To solve this problem, a mixed Eulerian-Lagrangian approach was applied. The concentration profile was calculated by solving the two-dimensional diffusion equation with appropriate boundary conditions. The growth velocity was determined on the basis of gradients of concentration in the border of the interface. Si interface evolution from the opened window was demonstrated.