Mechanism of sputtering of solid surfaces by ion-impact

Abstract

SECONDARY electrons and particles are ejected from a solid surface when it is struck by a beam of high energy ( ≥25 eV) ions. The majority of the ejected particles are neutral atomic and molecular species but a small proportion (typically 0.01% to 1%) carry a positive or negative charge. Two main theories have been advanced to explain the process; the ‘hot spot’ theory¹ and the ‘momentum transfer’ theory². We propose here a new theory in which bombarding species electronically excite the surface atoms of the target hence reducing the bonding energy of the species to the target.