Spoke behaviour in reactive HiPIMS
| Authors | |
|---|---|
| Year of publication | 2021 |
| Type | Article in Periodical |
| Magazine / Source | Plasma Sources Science and Technology |
| MU Faculty or unit | |
| Citation | |
| Web | https://doi.org/10.1088/1361-6595/abfbc5 |
| Doi | http://dx.doi.org/10.1088/1361-6595/abfbc5 |
| Keywords | reactive sputtering; spokes; reactive high power impulse magnetron sputtering |
| Description | Plasma in high-power impulse magnetron sputtering discharge, similarly to other discharges utilising E × B field (Hall thrusters, homopolar devices), undergoes self-organisation into the ionisation zones predominantly rotating in the E × B direction, called spokes. Many studies were conducted focussing on the characterisation of their appearance, mode number, rotational velocity, merging and splitting events in different experimental conditions. Nevertheless, only very little research has been conducted in the case of reactive sputtering, where only the general spoke characteristics were evaluated. A dual-image fast camera screening was utilised to capture plasma emission on 3'' Nb target in a reactive mixture of nitrogen and argon. Spoke characteristics were evaluated while overall pressure and supplied power was kept constant and the content of nitrogen in N2/Ar mixture was varied. The shape, velocity and spoke mode number were significantly affected by the higher content of N2 in the mixture. To distinguish between the effects of the modified target surface state and reactive gas present in the plasma volume on spokes experiments with compound NbN target were also performed. Surprisingly, no real differences of spoke behaviour between Nb and NbN targets were observed. |
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