Optimization of quantitative depth profiling with glow discharge mass spectrometry. Part 1. Optimization studies on crater shape and time–depth conversion

Abstract

Investigations have been performed using glow discharge mass spectrometry to determine the effect of glow discharge parameters such as voltage, current and pressure on the sputter rate and sputtered crater shape. Optimization of these parameters has been carried out on a multi-layer sample and is shown to produce a flat-bottomed sputter crater and a depth profile resolution as good as 0.03 µm (300 A). Sputter rates can be controlled to within ± 10%, and by establishing a library of such values for a wide variety of materials, the crater depth can be calibrated against analysis time to provide accurate depth quantification. Different sputter rates can be used for routine depth profiling of various coating thicknesses from 0.1 to 200 µm.