A matched filter technique for Auger depth profile sensitivity enhancement

Abstract

A matched filter technique is described which provides near-optimal enhancement of the signal-to-noise ratio for Auger depth profiling. This technique provides effective background suppression and is easier to implement than other recently described techniques, but does not deal as efficiently with spectral interferences. A simple BASIC subroutine is sketched and is applied to simulated Auger data. Experimental data from a ramped AlGaAs structure profiled simultaneously by Auger and SIMS (secondary ion mass spectrometry) are also analyzed. As compared with the standard peak-to-peak method, sensitivity is typically increased by a factor of two to four. It is shown that standard smoothing techniques offer comparable, though somewhat inferior improvements in sensitivity. A useful estimate for the maximum obtainable signal-to-noise ratio is also described.