Cones formed during sputtering of InP and their use in defining AFM tip shapes

• Published in: Applied surface science 1999-04, Vol.144, p.151-155
• Main Authors: Seah, M.P, Spencer, S.J, Cumpson, P.J, Johnstone, J.E
• Format: Article
• Language: English
• Subjects: AFM; AFM tip shape; Condensed matter: structure, mechanical and thermal properties; Electron, ion, and scanning probe microscopy; Exact sciences and technology; Indium phosphide; Physics; Scanning probe microscopy: scanning tunneling, atomic force, scanning optical, magnetic force, etc; Solid surfaces and solid-solid interfaces; Sputter cones; Structure of solids and liquids; crystallography; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Topography
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/S0169-4332(98)00794-6

Small structures, formed on InP surfaces during sputtering, cause loss of depth resolution in sputter-depth profiles but may be conveniently incorporated into a method for studying AFM tip shapes to define resolution in AFM images. The sputtered structures formed here are filaments, often called cones, whose indium tips have a radius of about 10 nm. By sputtering with argon ions in the energy range, 4 keV to 8 keV, it is shown that the height of the filaments is critically dependent on the sample temperature. At room temperature, or below, the height is very small but, at 260°C, they grow to 200 nm. An Arrhenius plot for several temperatures indicates growth, probably by a stress-induced diffusion mechanism driven by charging of the indium cap by the ion beam. AFM images of these structures may be averaged to give reliable pseudo-reconstructions of the AFM tip.