The characteristics of fast electrons (e-) and heavy particles (N2+, N+, N2f, Nf) in the cathode dark space (CDS) of nitrogen dc glow discharge are simultaneously studied by Monte Carlo simulation. The calculated energy and angular distributions of these particles at different positions from the cathode provide a clear picture of their transport behaviours within the CDS. The density and mean energy of these particles indicate that the electrons and the atomic ions (N+) are the main high-energy species and the molecular ions (N2+) are the major ions in the CDS. It can be seen from the energy distributions of the bombarding particles at the cathode surface that the molecular ions and the fast atoms (Nf) are the main active species participating in the cathode nitride material synthesis process. The influence of the backscattering of the electrons from the negative glow to the CDS is also investigated. All the calculated results provide good information on the spatial characteristics of the particles considered in this paper and also their internal connections in the CDS of nitrogen dc glow discharge.

Grid-enhanced plasma source ion implantation (GEPSII) is a newly proposed technique for inner surface modification of materials with cylindrical geometry. In this paper, a collisional fluid model is used to investigate the ion sheath dynamics between the grid electrode and the inner surface of a cylindrical bore during the GEPSII process. Assuming the initial ion density along the radial direction is not uniform but determined by diffusion mechanisms, the effects of grid electrode radius, target radius and ion–neutral collisions on the ion dose and impact energy are investigated by solving fluid equations for ions coupled with Boltzmann assumption for electrons and Poisson's equation. The results show that small gap distance between grid electrode and target is favourable to increase the ion dose and impact energy on the target. In addition, ion–neutral collisions can reduce both the ion dose and impact energy.