Experiments on the formation of Cu-rich particles at the surface of high-quality thin films of this material were carried out. The films, deposited onto (001)LaAlO3, were grown by using in situ off-axis sputtering methods. The particle formation which was observed could be described in terms of classical thin-film nucleation and growth models which were based upon the concept of capture zones. On the basis of the results, the activation energy for the surface diffusion of the Cu atoms which formed the particles was estimated to be equal to 1.5eV at temperatures ranging from 670 to 750C.

Z.Han, T.I.Selinder, U.Helmersson: Journal of Applied Physics, 1994, 74[4], 2020-5