Quantitative depth profile analysis by glow discharge

The development of dc glow discharge spectrometry for depth profile analysis is reviewed. Different approaches to quantification of depth profile measurements into elemental concentrations vs depth are discussed. Methods for quantitative glow discharge optical emission spectrometry (GD-OES), based on the concept of emission yield (emission intensity/sputtered weight), are described in detail. The alternative quantification method developed at the Swedish Institute for Metals Research, which also incorporates compensation for variations in excitation parameters, is presented. Current work on GD mass spectrometry (GD-MS) for quantitative depth profile analysis is briefly reviewed. Several applications of quantitative GD spectrometry to metallic and non-metallic surface layers are presented. Some of the remaining problem areas with regard to quantification are discussed; reference materials, accuracy of the depth determination, influence of released gaseous species, and correction for background signals.