(422h) Investigation of Film Surface Roughness and Porosity Dependence On Lattice Size in a Porous Thin Film Deposition Process

Thin film growth processes are significant in many areas, e.g., manufacturing of microelectronic devices and solar cells. To understand the mechanisms and further improve the operating conditions and yield, extensive research work has focused on the study of thin film growth processes via both experiments and simulations. Due to the limitations of the currently available computing power, numerical methods cannot provide microscopic simulation results that can access realistic wafer dimensions. However, simulation results with finite lattice-size systems provide insights to the growth processes and evolution of film microstructure.

This work carries out a thorough study of the dependence of film surface roughness and porosity on lattice size in a porous thin film deposition process. Specifically, a porous thin film deposition process which includes atom adsorption and migration is considered and is modeled via kinetic Monte Carlo simulation on a triangular one-dimensional lattice. Extensive numerical simulations are carried out to determine the variation of the film surface roughness and porosity with the lattice size. We find that for sufficiently large lattice size the steady-state value of the expected film porosity has a weak dependence on the lattice size and the steady-state value of the expected surface roughness square varies linearly with lattice size. A theoretical analysis based on stochastic PDE descriptions of film morphology is carried out to support and explain the computational findings.