Metal–metal epitaxy on silicon: Cu/Ni/Cu ultrathin films on 7×7-Si(111)

Cu/Ni/Cu heterostructures have been in situ deposited on the 7×7 reconstructed Si(111) surface. A number of complementary techniques, such as in situ low-energy, medium-energy and Kikuchi electron diffraction and ex situ X-ray diffraction, were used in order to characterise the growth process and the structural properties of the films. It is found that the growth mode of metallic films is characterised by the presence of twinned islands induced by the 7×7 reconstruction of the Si(111) substrate. This work can stimulate further application of the metal–metal epitaxy on silicon to grow high quality ultrathin magnetic films to be integrated in microelectronic devices.