Effect of energy on direct ion beam deposition of carbon thin films: induced defects and graphitization

Abstract

The direct deposition of ions at low energy enables fine control of the fundamental processes of thin film formation. Using a source of carbon and nickel ions with energy ranging from a few tens to a few hundreds of electron volts, combined with an ultra-high vacuum scanning electron tunneling microscope, we have studied the formation of thin films for thicknesses equivalent to less than one atomic layer. We have revealed the influence of ion-induced defects on the formation mechanisms of the thin film as a function of ion energy using the dynamic scaling analysis of the roughness of the thin film terminal surfaces. In the case of carbon ions we acknowledge the formation of an sp2 bonded layer at 300°C, that is above the critical temperature where the formation of a diamond-like carbon sp3 layer recess as described by the subimplantation model [4].