''The effect of discharge conditions on the resolution attainable for in-depth profile analysis of metallic thin layers by glow discharge optical emission spectrometry''

In a further attempt to understand the influence of physical variables governing depth profile analysis by direct current glow discharge (dc-GD) a study of the parameters affecting the etched craters has been carried out, The evaluation has been performed in terms of sputtering rate, shape of the crater (which limits the resolution in the in-depth profile analysis) and redeposition effects. Galvanneal(R), which consists of a galvanized coating of about 10 mu m on steel, followed by annealing to form ZnFe intermetallic phases, has been used as a model sample material. In order to allow for a better in-depth resolution and for higher time periods of stability in the discharge, some modifications in the classical Grimm-type source have been introduced and the effect of cathode - anode distance, the influence of voltage and the role of discharge pressure were studied, Results showed that using discharge voltages of 1200 V, pressures between 1.07x10(2) -2.67xl0(2) Pa and anode - cathode distances in the interval 0.5 - 0.6 mm in such modified dc-GD device highly flat crater profiles, with low redeposition effects, were obtained. The relative depth resolution obtained in the proposed system was 0.33.