Formation of narrow nanocluster bands in Ge-implanted SiO sub(2)-layers

The paper describes the formation of Ge nanocrystals in thin thermally grown SiO sub(2)-layers (d sub(ox) less than or equal to 100 nm) using implantation of 10 super(15)-2x10 super(16) Ge super(+)/cm super(2) and subsequent annealing. Although the implanted Ge depth profile is distributed over almost the whole SiO sub(2) layer, a very narrow band (typical width 5 nm) of Ge nanoclusters very close but well-separated to the Si /SiO sub(2)-interface is formed by self-organization under specified annealing conditions. A possible mechanisms for this self-organization process is discussed including nucleation phenomena, Ostwald ripening and defect-stimulated interface processes. Simple MOS-structures were prepared and the effect of charge storage inside the clusters has been derived from C-V characteristics.