Growth and thermal annealing of Cu on HfSiO4

The interface between Cu and HfSiO4 films synthesized using physical vapor deposition (PVD) at 300 K has been examined with in situ low-energy ion scattering (LEIS), in situ X-ray photoelectron spectroscopy (XPS), and ex situ atomic force microscopy (AFM). Cu deposited on HfSiO4 at 300 K is adequately described by a two stage model in which a single layer forms up to ∼85% of completion, at which point 3D clusters form in a process involving partial de-wetting of previously deposited, as well as added, Cu. XPS simulations, based on cluster structures consistent with LEIS data, are used to determine optimum structural models. During annealing at 573 K, there is compelling evidence for Cu restructuring but no evidence for chemical changes. During 20 min at 573 K, a Cu film with an ensemble average thickness of 0.56 nm comprising small clusters undergoes extensive restructuring to larger clusters with average diameter and height of 26 (±3) and 2.3 nm, respectively. The relatively narrow diameter distribution may be attributed, in part, to a self-limiting growth originating in the as-deposited strain fields at Cu-HfSiO4 interface