Study of the transport of titanium neutrals and ions in the post-discharge of a high power pulsed magnetron sputtering device

This paper deals with the diagnostics of a high power pulsed magnetron sputtering device (HPPMS). The HPPMS plasma was spatially and temporally characterized in the post-discharge using optical absorption spectroscopy and Langmuir probe time resolved measurements. A circular titanium target was used, the buffer gas was argon and the pressure was fixed at 4 Pa. The titanium densities (neutrals and ions) were measured by a pulsed resonant absorption spectroscopy technique. We found an ionization degree higher than 0.5. Comparison beetween the experimental results and a simple one-dimensional model of diffusion shows that in these conditions, the transport of neutral and ionized sputtered atoms is mainly controlled by diffusion (ambipolar diffusion for ions).