The substrate table was positioned in the middle of the cylindrical vacuum chamber, 90 mm below the hollow cathode orifice. A substrate bias (Vp) of 60 V was applied to the substrate table during all measurements to mimic the process conditions of the e-CVD process. FeCp2 was kept in a stainless-steel evaporator, heated to 75 °C using a heating jacket. The FeCp2 was then delivered to the vacuum chamber using Ar as carrier gas (4.2 SCCM) through heated (100 °C) vacuum lines to avoid precursor condensation.