Selected area, stationary beam cratering for high sensitivity depth profiling with a computerized Auger microprobe

Abstract

The use of improved methods of “crater edge profiling” as a viable alternative to conventional depth profiling by sputter etching and Auger analysis is discussed. The emphasis is placed upon utilizing a stationary ion beam (full width at half- maximum, about 200 μm) from a differentially pumped gun, the beam of which can be selectively positioned on the sample surface for localized cratering. A variety of samples of Au/Cu, Au/Zr, Ag/Si and silicon either uncoated or coated in situ with metal were used for demonstrating different aspects of this experimental approach and for mapping with Auger, secondary and elastically backscattered electrons. A thin oxide layer on silicon ( d OX ≈ 1.2 nm) was very easily detected and measured by line scans across shallow craters (tan α ≈ 10 -5).