Pulsed electron beam deposition of oxide thin films

Abstract

In this work we studied the pulsed electron beam deposition (PED) method using a channel-spark discharge as the electron source. In order to estimate the potential of the PED method, thin films of zinc oxide, zirconium tin titanate, barium strontium titanate and biocompatible oxides were grown and investigated taking into account two important points: the surface morphology and the film composition. We showed that PED leads to films free from micrometre size droplets and by a careful optimization of the beam parameters it is possible to drastically reduce the density and size of nanoparticulates. In fact, by studying the relationships between the discharge parameters, electron beam characteristics and surface morphology of films we evidenced that a decrease in the beam energy leads to a drastic reduction in the nanoparticulate density. The composition of the various oxide thin films investigated in this work is close to that of the target, as in the case of pulsed laser deposition, even in the case of complex oxide compounds. Hence, smooth and dense thin films preserving the composition of the bulk target can be obtained by the PED method. The study by fast imaging of the expansion of the plasma plume produced by the pulsed electron beam interaction with the target indicates that the kinetic energy of the species emitted by the target is roughly in the 10–50 eV range.