Preliminary study of the role of discharge conditions on the in-depth analysis of conducting thin films by radiofrequency glow discharge optical emission spectrometry

Abstract

A radiofrequency glow discharge (rf GD) device was evaluated for the in-depth profile analysis of thin conducting films by optical emission spectrometry. Samples consisted of steel with Al–Zn coatings of approximately 20 µm thickness. The role of the discharge conditions, including rf generator power, pressure in the discharge chamber and the limiting orifice (anode) diameter on the temporal evolution of the intensity of Zn I 334.5 nm emission and on the shape and depth of the craters produced were investigated. These studies provide information about the variations in the in-depth resolution and sputtering rates when the discharge conditions are varied. Results show the critical role of the internal diameter of the anode upon the crater shape and the penetration depth as well as a strong dependence of the etching rate with rf power and gas pressure of the discharge. The shapes of craters obtained after different sputtering times (from 3 to 60 min) were also measured, with a linear relationship between penetration depth and the sputtering time verified.