The role of backscattered energetic atoms in film growth in reactive magnetron sputtering of chromium nitride

Abstract

In this work the impact of backscattered energetic atoms on film growth in reactive sputtering of CrN x (x 1) is manifested. We use film and plasma characterization techniques, as well as simulations in order to study the dynamics of the target-discharge-film interactions. The results show that the primary bombarding species of the growing film are N + 2 plasma ions, which are neutralized and backscattered by the target in the form of atomic N. It is shown that the backscattered N atoms have energies which are significantly higher than those of other bombarding species, i.e. the backscattered Ar atoms, the sputtered atoms and the plasma ions. Moreover, it is found that CrN films exhibit compressive stresses of 2.6 GPa and a density close to the bulk value. We attribute these properties to the bombardment by backscattered energetic atoms, in particular N. Pure Cr films are also studied for reference.

Sputter deposited NbCxNy films: Effect of nitrogen content on structure and mechanical and tribological properties

“…We attribute the increased compressive stress upon introduction of N 2 in the processing gas to N 2 + -ions that are implanted in the growing film, occupy interstitial sites, and cause compressive stress; while the majority of implanted Ar + ions will diffuse to the surface, causing less pronounced stress. In addition, backscattered N-atoms have a higher energy than backscattered Ar and, in turn, can cause larger layer densification and compressive stress [49,50]. The reduction in the compressive stress for y N 0.44 is attributed to the increasing fraction of the amorphous matrix phase, as evidenced by the larger C-C and C-N bond fraction measured by XPS, which may provide pathways for stress relaxation through diffusion of interstitial C and N from the Nb-carbonitride phase to the amorphous matrix phase as well as plastic shear deformation within the amorphous matrix.…”

A comparative study of CrAlN films synthesized by dc and pulsed dc reactive magnetron facing target sputtering system with different pulse frequencies

“…It has been shown that film properties, such as high compressive stresses and high roughness can be explained by the energy of the incident species on the surface of the growing film [30,31]. It is shown that when the energy of the incident species on the film surface is low, their energy transfers to the surface of the growing film and affects the surface roughness [5,31,32].…”

“…It is shown that when the energy of the incident species on the film surface is low, their energy transfers to the surface of the growing film and affects the surface roughness [5,31,32]. On the other hand, the species are supplanted into the film when their energy increases, which, in turn, forms higher internal stresses [33][34][35][36].…”

Structure of high-reflectance La/B-based multilayer mirrors with partial La nitridation

“…9 To find out the nitrogen pressure required during the deposition, modelling of the reactive sputtering process could be employed, for instance as developed by S. Berg et al 11 However, without precise values of the La and LaN sputtering yields (reactive deposition), the sticking coefficient of nitrogen to lanthanum, without taking into account nitrogen ion implantation into the target, etc., accurate calculations seem to be impossible. Moreover, in the plasma N • , N + , and N + 2 are produced via various electron-impact reactions, 12 and positively charged species impinge the La target, neutralize (with certain probability) and reflect back, in the direction of the growing La layer, 13 performing additional nitridation of deposited La. Modern advanced models of reactive deposition, for instance 14 require extraction of certain parameters by fitting the experimental data, 15 which is time consuming.…”