Film forming properties of silicon nanoparticles on SixNy coated substrates during excimer laser annealing

Abstract

In this article we investigate the film forming properties of excimer laser annealed silicon nanoparticles on non-silicon substrates. In contrast to their film forming properties on oxide free silicon substrates, the nanoparticle thin film tends to dewet and form a porous µ-structure on the silicon nitrite covered glass model substrates considered for our investigation. This is quantified using a SEM study in conjunction with image processing software, in order to evaluate the µ-structure size and inter µ-structure distance in dependence of the laser energy density. To generalize our results, the film forming process is described using a COMSOL Multiphysics ® fluid dynamics model, which solves the Navier Stokes equation for incompressible Newtonian fluids. To account for the porous nanoparticle thin film structure in the simulation, an effective medium approach is used by applying a conservative level set one phase method to our mesh. This effort allows us to predict the Si melt film formation ranging from a porous Si µ-structure to a compact 100% density Si thin film in dependence of the substrate / thin film interaction, as well as the laser energy used for the nanoparticle processing.