Thin-layered surface depth profiling by using dc voltage modulation technique in glow discharge optical emission spectrometry (GD-OES)

摘要

Up to now, glow discharge optical emission spectrometry has been applied as a very useful method for a bulk analysis of conducting or non-conducting solid samples. Recently, a number of glow discharge users begin to interest in the analysis of thin-layered materials by using glow discharge optical emission and mass spectrometry. The dc voltage modulation technique has been used for analysis of trace elements in the steel samples with a good precision and sensitivity. Conventional glow discharge plasma can be easily modulated by means of superimposing of an alternating voltage on the dc bias voltage. The intensity of emitted light will be varied according to the applied alternating component, so that only the modulated component can be detected selectively by using a lock-in amplifier. In this study we had some parametric studies on emission characteristics of the dc voltage modulation glow discharge plasma, and then we measured a depth profile of a 100-nm-order of Ni-electroplated steel sample, and some favorable results were obtained.