Simulation of N2 microhollow cathode discharge and cathode sputtering by using a PIC/MC model

Abstract

The nitrogen microhollow cathode discharge and Ti cathode sputtering, bombarded by ions (N2+, N+), have been studied using a two-dimensional PIC/MCC model. The behavior of ions (N2+, N+) and sputtered atom (Ti), and the thermalization process of the sputtered atoms in a nitrogen microhollow cathode discharge are simulated. The results show that hollow cathode effect is due to electron oscillations in the overlapping negative glow under our simulation condition. The densities of ions (N2+, N+) in the microhollow cathode discharge are two orders in magnitude greater than that in the conventional hollow cathode discharge; but the distributions and sizes of the mean energy of the ions (N2+, N+) are almost the same. The density of N2+ is fivefold as much as that of N+ in the microdischarge space; however, the maximum of mean energy of the latter is twice larger than the former. For various parameters (P, T, V), the densities of ions(N2+, N+) bombarding the cathode internal surface are almost uniformly distributed, and their mean energy are almost the same. When these atoms are 0.15 mm away from the cathode. The sputtered atoms are almost thermalized completely.