Silane gas-source atomic layer epitaxy

Silicon atomic layer epitaxy (ALE) has been performed on Si(100) by utilizing a self-limiting adsorption of silane at room temperature and a thermal reactivation of the surface for further adsorption. The presence of the self-limiting adsorption was confirmed through a saturation of the adsorbed molecules above 8000 L of silane dose. This saturation is shown to be caused by surface hydrogen atoms, which on annealing up to 700°C all desorb from the surface, converting the desorbed surface to an active one for further adsorption. By repeating the silane-adsorption/thermal-desorption processes, Si epitaxial growth with a unit of 0.25-0.33 ML has been realized. Mechanisms for self-limiting adsorption of silane and for sub-monolayer growth unit in ALE are also discussed.