High-fluence Co implantation in Si, SiO2/Si and Si3N4/Si Part III: heavy-fluence Co bombardment induced surface topography development

The surface topography development of Si(1 0 0), Si(1 1 1), oxide/Si and ni tride/Si structures under high normal fluence (1 x 10(16)-2.6 x 10(18) ions cm(-2)) keV Co metal vapour vacuum are (MEVVA) irradiation has been invest igated by scanning electron microscopy (SEM). The results show that for nor mal fluences up to similar to 10(17) ions cm(-2), the surface topography re mains flat. As the fluence increases, pores develop and grow to form a colu mnar structure. At even higher fluences the columns are eroded to form an a cicular structure. Deposition of a silicon dioxide or nitride layer on the Si surface leads to a significant suppression of the onset fluence for the formation of a rough surface. The porous surface could not be transformed t o the network of acicular structures or a flat surface by high temperature annealing. (C) 1999 Elsevier Science B.V. All rights reserved.