Reactions of Y2O3 films with (001) Si substrates and with polycrystalline Si capping layers

Abstract

We use electron energy-loss spectroscopy in scanning transmission electron microscopy to investigate interfacial reactions of chemical vapor deposited ${\mathrm{Y}}_2{\mathrm{O}}_3$ films with the Si substrate and with in situ polycrystalline Si (“poly-Si”) capping layers after postdeposition annealing. We find that in situ capping layers significantly reduce the formation of ${\mathrm{SiO}}_2$ at the interface with the substrate, but silicates form at the substrate and the capping layer interfaces. Predeposition nitridation of the Si surface can impede the reaction at the substrate interface, resulting in crystallization of ${\mathrm{Y}}_2{\mathrm{O}}_3$ in the film interior. Possible mechanisms of the silicate formation are discussed.