On glow-discharge sputtering of iron and steels in a commercial deposition plant

The sputtering rates of iron films and various steels exposed to argon–hydrogen pulsed-DC glow discharges in a commercial plasma-assisted chemical vapour deposition plant have been studied experimentally. The sputtering rate of iron was obtained from measurements of the film thickness before and after glow-discharge exposure, using Rutherford backscattering spectrometry, and the sputtering rates of the steels were obtained from shifts of positions of implanted Xe markers in Rutherford backscattering spectra. Through anode-catcher experiments, the dependence of the sputtering rate on the oxygen partial pressure was measured. To investigate any influence of the background oxygen pressure on the plasma (the cathode ion bombardment), energy spectra of the ions hitting the cathode were also recorded. With finite oxygen background pressures, iron sputtering rates much smaller than the ones corresponding to sputtering yields of iron oxides were measured. In fact, due to these low rates, it was only possible to establish upper limits to the iron and steel sputtering rates in glow discharges in the commercial chamber.