Study on the treatment capability of a plasma-based ion implanting trench-shaped target

Abstract

The treatment capability of a plasma based ion implanting two-dimensional trench-shaped target has been discussed through particle-in-cell simulation. By analysing time-dependent expansion of the plasma sheath and the ion implantation parameters during a high voltage pulse, we found that the sidewall of the trench could not be implanted effectively. Trenches with the same depth and three different widths were simulated in this paper. Simulation results show that the plasma sheath conforms to the target better in the case of a wider trench, but it tends to expand as a plane for the majority of the pulse. The ions accelerated in such a sheath would impinge vertically on the upper surface and the bottom of the trench with the converging at the convex corner and diverging at the concave corner, but neglecting the sidewall. After the short initial stage of the pulse when the sheath is conformal to the target well (about 1/10 of the pulse duration), the ions impact the sidewall of the trench with grazing angle, lowest ion impact current, and lowest ion impact energy. All the above three factors would induce a severe sputtering effect, reduce ion implantation depth and decrease retained dose. Increasing the width of the trench would alleviate this effect, but to a slight extent. The plasma based ion implantation process in trench cases is similar to ion beam implantation with a large beam and would not get the effective implantation for all the surfaces of the trench.

Microstructure and cutting performance of V-C based coatings deposited by HIPIMS/UBM

“…In the case of cutting tools, the plasma sheath compresses near sharp edges as shown in fig.4.1. This enhances the electric field at the vicinity of the edge, which causes higher material removal at cutting edges than in the centre of the substrate [132,133]. This may lead to edge blunting.…”

“…Effect of Pulse Energy on the Ion Etching Figure 4.1: Sheath edge curves around a square corner (after [132] and [133]).…”