Pressure dependence of Ar${\hspace{0pt}}_2^+$ , ArTi⁺, and Ti${\hspace{0pt}}_2^+$ dimer formation in a magnetron sputtering discharge

Abstract

Formation of Ar+ and Ti+ monomers and of Ar, ArTi+, and Ti dimer ions in a magnetron sputtering discharge with a Ti cathode and at argon gas pressures of 0.3–2.1 Pa was investigated by means of energy-resolved mass spectrometry. An unbalanced 2 inch magnetron operated in direct current mode with a power of 150 W (typical operation voltage V) was employed. Energy spectra of Ar+ and Ti+ ions show distinct features which are related to the specific formation processes taking place at the Ti cathode or resulting from gas phase reactions. Formation of Ar, ArTi+, and Ti dimer ions show pronounced pressure dependencies which can be attributed to distinct formation and loss processes. Ti ions originate from direct sputtering of Ti2 dimers and the subsequent ionization in the plasma region above the cathode.

Ion formation in an argon and argon-oxygen gas mixture of a magnetron sputtering discharge

“…Energy distributions of singly charged Ar + and Ti + and doubly charged Ar 2+ and Ti 2+ ions are displayed in figure 2 for six different gas pressures ranging from 0.3 Pa to 5.5 Pa. The present measurements extend recent results for singly charged ions to larger pressures [20]. All energy distributions are plotted as a function of the scaled energy E E q = , where E is the kinetic energy and q the charge number.…”

“…The experimental set-up has been described in detail before [20][21][22]. The experiment is performed in a vacuum chamber which is pumped to a base pressure of less than 10 −5 Pa. Argon (purity 99.999%) and oxygen gas OPEN ACCESS RECEIVED…”

“…In this paper we investigate the ion composition in a magnetron sputtering discharge with a titanium target. Recent measurements for pure argon gas are extended to larger gas pressures up to 5.5 Pa providing a clearer picture of the pressure dependency [20]. Positively and negatively charged ions are observed for an argon/oxygen gas mixture, resulting from gas phase collisions and from interaction with the sputtering target.…”

“…Energy-resolved mass spectrometry is performed with a commercial Hiden EQP 1000 mass/energy analyzer (Hiden Analytical Ltd., UK). Further details of the instrument and of the analyzer's settings can be found elsewhere [20]. The instrument is mounted opposite to the magnetron's race track at a distance of 45mm from the cathode.…”

New Insight into the Gas Phase Reaction Dynamics in Pulsed Laser Deposition of Multi-Elemental Oxides

“…The background gas Ar has a similar mass (40 amu) and kinetic diameter (340 pm, spherical) to O2 (32 amu, 346 pm elliptical) but is considered to be chemically inert with a comparable geometrical cross section [17]. Chemical reactions with Ar are known, but none of these known products have yet been detected [18,19]. The measured IEDs were the result of both elastic and inelastic collisions during the plume expansion in the respective atmospheric environment.…”