Mass‐to‐charge ion composition of plasma in a magnetron discharge with reactive sputtering of titanium target

Abstract

In this study, we have analyzed the ion mass‐to‐charge composition of the plasma of a magnetron discharge with a titanium target operating in various gases: argon, nitrogen, oxygen, and their mixtures. The addition of nitrogen and oxygen to argon significantly affects the ion spectrum in the magnetron discharge plasma. The increased fraction of nitrogen in the mixture of more than 15% contributes to the dominance of atomic nitrogen ions in the spectrum and leads to a strong decrease in both the plasma density and the metal (titanium) ion fraction in the plasma. The addition of more than 10% oxygen leads to the complete absence of metal ions in the spectrum. These effects are associated with the formation of nitride and oxide layers on the titanium target surface, thus inhibiting the introduction of metal ions in the plasma.

Mass Spectra Fitting as Diagnostic Tool for Magnetron Plasmas Generated in Ar and Ar/H2 Gases with Tungsten Targets

“…It is widely used to identify elements, atoms, molecules, and their ionization states, and to determine the plasma species' molecular weight and their isotopic abundances. By injecting small amounts of solid or liquid materials such as polymers, proteins, and lipids in plasma via spraying, vaporization, ablation [1], or sputtering [2], the variety of sample types that can be analyzed using this method increases tremendously. Mass spectrometers are used in analytical systems in combination with a large range of ionization methods [3,4] (such as discharges, ions bombardment of surfaces in secondary ion mass spectrometry (SIMS), photoionization, electrospray ionization, and matrix-assisted laser desorption ionization (MALDI)).…”

“…For example, peaks with similar shapes and large widths have previously been reported in the literature. Tyunkov et al presented in [2], the ion mass-to-charge composition of the plasma generated by magnetron discharge with a titanium target and the study of the modification of the spectra when various gases are introduced in the discharge. The existence of five stable isotopes of Ti (with adjacent mass values) produces a superposed spectrum in which the area of each peak cannot be easily separated to obtain the concentration of each isotope.…”