Distribution of implanted current on trench-shaped targets in plasma-based ion implantation and deposition

The ion current at each position of a trench-shaped target was observed in plasma-based ion implantation and deposition (PBII&D), where a titanium cathodic arc at a nitrogen pressure of 8 Pa was used as a plasma source. The width and height of the trench were varied. The arc current and voltage are 80 A dc and 20 V. The ion current distribution inside trench was investigated under a strong flow of the plasma species. It was experimentally found that the ion current decreases at the bottom and at the side wall of a narrow width trench, while the target voltage increases. The distribution of ion current is caused by evolution of the ion sheath and the plasma density inside the trench.