Fabrication of Ge nanocrystals in SiO2 films by ion implantation: control of size and position

Abstract We have fabricated Ge nanocrystals in SiO 2 films by ion implantation and thermal annealing. A uniform Ge depth-concentration profile in the SiO 2 layer is achieved by sequential Ge + -ion implantation at different kinetic energies (multi-energy ion implantation). After thermal annealing, the produced Ge nanocrystals have a narrow size distribution. In addition, low-energy ion implantation produced Ge nanocrystals in a very narrow region in the thin SiO 2 layer. The size fluctuation of nanocrystals produced by low-energy and multi-energy ion implantation is much smaller than that by conventional single-energy ion implantation and co-sputtering techniques. It is demonstrated that these improved ion implantation methods are useful for the control of the size and position of nanocrystals formed in dielectric materials.