Cathode spots in a magnetically steered arc source were studied under low-pressure noble gas (Ar) and reactive gas (N2, O2) atmospheres. The plasma was observed using a streak camera coupled with a long-distance microscope to study the evolution of cathode spots with high temporal and spatial resolution. We find two well-known types of cathode spots: “type 1” for less bright spots eroding the compound layer on the cathode surface and bright “type 2” spots on (clean) metallic surfaces. Cathode spots are characterized by a sequence of microexplosions that give the impression of a moving spot, which, in the presence of a magnetic field, is generally in the retrograde direction. However, the apparent displacement can also go in the opposite, the Amperian direction, especially when nitrogen is present. In oxygen, spot ignition often happens in approximately the same location repeatedly. For type 2 spots, we detected an apparent motion mainly in the retrograde direction with distinct jumps to new locations. Via the effects of spot appearance, we note the competing effects of cathode cleaning by spot-induced material removal (erosion) and compound formation in the presence of reactive gas. The streak images were analyzed by fast Fourier transformation, and we found that the arc fluctuations are stochastic without specific frequencies. The colored random noise (CRN) index tends to be reduced in the presence of a compound layer, indicating an enhanced spot ignition probability. A reduced CRN index implies reduced feedback (influence) of previously active spots, which is most apparent in the presence of elevated oxygen pressure.

We study the conversion of two polymeric silicon precursor compound layers (perhydropolysilazane and polydimethylsiloxane) on a silicon wafer and polyethylene terephthalate substrates to silicon oxide thin films using a pulsed atmospheric pressure plasma jet. Varying the scan velocity and

Process stability and reproducibility are essential for highly precise manufacturing with reactive ion beam etching (RIBE) in optics industry. Therefore, the ion beam source characteristic must be well known. For this study, a Kaufman-type broad beam ion source operated with CHF3 and O2 is characterized with energy selective mass spectrometry and Faraday measurements. These results are compared with etching experiments on SiO2, Si, and AZ®1505 photo resist. The influence of the source setup and process conditions on ion beam composition, ion energy distribution, and the etch selectivity are discussed. It was found that etch selectivity applying different ion beam currents at a fixed feed gas composition correlate with resulting ion beam composition. Due to a change in ion beam composition, selectivity also changes with the total volumetric mass flow of the feed gas at a fixed ion beam current and constant mixing ratio of CHF3 and O2.

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