Synthesis of Ge nanocrystals in thermal SiO 2 films by Ge + ion implantation

Abstract

Ge-nanocrystal-embedded SiO 2 films were fabricated by Ge + implantation into SiO 2 films thermally grown on crystalline Si wafers, and were examined by Fourier transform infrared absorption spectroscopy, Raman spectroscopy, and X-ray photoemission spectroscopy. Due to Ge + ion implantation, the SiO 2 film moved off stoichiometry, and there were Ge oxides formed in it. The precipitation and growth of Ge nanocrystals (nc-Ge) were found to be related to some thermodynamical reductions of the Ge oxides during annealing. The average size of nc-Ge increases from ∼3 nm to ∼6 nm when the annealing temperature increases from 400°C to 1100°C.