A novel method to determine the ion sputter coefficient of dilute segregating impurities

Abstract

A combination of linear programmed heating (LPH) and 3 keV Ar +- ion sputtering was used to obtain Sn sputter coefficients at room and elevated temperatures using a novel new method. At room temperature the determined value agrees well with the elemental sputter yield, Y Sn=2.5, if sputter yield amplification (SYA) of a submonolayer thin Sn film on a Cu(1 1 1) surface is taken into account. However, at high temperature the sputter coefficient decreases to 1.1. This decrease can be explained if it is assumed that not all Sn atoms are removed from the surface into the vacuum by the sputtering process, but knocked on into the bulk of the Cu matrix. At elevated temperatures these Sn atoms segregate back to the surface and can be sputtered once again.