Analysis of the Transport of Ionized Titanium Atoms in a Highly Ionized Sputter Deposition Process

Abstract

This paper deals with the transport of metallic ions in a highly ionized sputter deposition process, usually called high power pulsed magnetron sputtering (HPPMS) device. The space and time variations of titanium ions density were determined by time-resolved optical absorption spectroscopy (TROAS) and the electron density by Langmuir probe technique. We studied the influence of an additional radio frequency (RF) plasma generated by a one-loop coil in the HPPMS post-discharge. Measurements showed that the transport of titanium ions was accelerated when the RF power applied on the coil was increased. These experimental data are quite well fitted by results obtained from a simple one-dimensional ambipolar diffusion model, indicating that this acceleration is due to the increase in the ambipolar diffusion coefficient when increasing the RF power.