GERMANIUM-CARBON MULTILAYER FILMS PREPARED BY MAGNETRON SPUTTERING - STRUCTURE AND THERMALLY-INDUCED FORMATION OF GE-NANOCRYSTALS

The investigated amorphous germanium-carbon multilayers are a novel sy stem for the synthesis of germanium nanocrystals. The structure of the multilayers was studied by cross-sectional TEM and X-ray reflection. With increasing distance from the substrate, an increase of the interf aces roughness is detected. Roughening of interfaces is mainly ca;sed by germanium growth, whereas carbon smoothes the interfaces. Taking th ese effects into consideration, the simulated X-ray reflection spectra agree well with measured spectra. After annealing at 870 K, crystalli zation of the germanium sublayers is observed. The crystallite size is equal to the thickness of the Ge-layer in the range from 25 nm down t o 3 nm, what is confirmed by X-ray diffraction and TEM. (C) 1997 Elsev ier Science S.A.