Channeling study of structural effects at the Al(111)/Si(111) interface formed by ionized cluster beam deposition

Epitaxial Al(111)/Si(111) films grown by the ionized cluster beam technique have been studied using the high-energy He+ channeling technique. No observable strain has been detected between the Si substrate and the Al layer despite their large (∼25%) lattice mismatch. Displaced Al atoms have been observed in the Al film, which increases with the depth and reaches 30% near the Al/Si interface. A large step increase of dechanneling occurs at the Al/Si interface which might be accounted for by the existence of ‘‘semicoherent’’ interface in which four Al planes are matched to three Si planes.