GOLD CLUSTERS PRECIPITATION AT THE INTERFACE BETWEEN NI(AU) SILICIDESAND (111)SILICON

The solid-state reaction between a nickel (7 at. % gold) film and a si licon substrate at temperature lower than the gold-silicon eutectic te mperature (370 degrees C) is examined by transmission and scanning ele ctron microscopy and by Rutherford backscattering spectrometry. Epitax ial NiSi and preferentially oriented Ni2Si are present and gold precip itation occurs at the inner interface. This gold precipitation leads t o a peculiar backscattering spectrum which is analyzed taking into acc ount morphological information. The driving forces leading to gold red istribution are interpreted in terms of surface energies and chemical interactions with silicon. (C) 1995 American Institute of Physics.