Pathway for a low-temperature deposition of α-Al2O3: A molecular dynamics study

Thin films of α-Al2O3 are of high interest because of their mechanical properties. Previously, the preparation of Al2O3 has been described in terms of extrinsic process parameters, such as total pressure, oxygen partial pressure or substrate bias potential. In this paper, the growth of Al2O3 is studied by atom-by-atom molecular dynamics simulations, focused on intrinsic process parameters such as ion energy, ion fraction in the particle flux, growth temperature and growth template. While the preparation of α-Al2O3 by currently available techniques requires temperatures of around 1000 °C (well above the typical softening temperature of tool steel substrates), the paper presents a narrow window of intrinsic process parameters which leads to an uninterrupted epitaxial growth or growth of previously nucleated α-Al2O3 at low temperatures.