Spatial characterization of Ar–Ti plasma in a magnetron sputtering system using emission and absorption spectroscopy

Abstract

We present experimental results of the spatial distribution of Ar and Ti optical emission and absorption lines in Ar?Ti plasma during sputtering of Ti. Measurements were performed in a dc magnetron reactor with movable planar magnetron using optical emission/absorption spectroscopy. A study was made for two different working pressures: 0.5 and 4?Pa. The results show that the intensity of emission lines decay exponentially with the increase in the distance from the target with two different decrements which correspond to the different parts of the discharge, namely the plasma region with a steep decay (up to about 1.5?cm from the target) and the 'far' region with a slow decay (more than 2?cm away from the target). Ti absorption data reveal similar behaviour. The emission decrement values which correspond to the steep decay of intensity lie in the range 1.4?3?cm?1, whereas those for slow decay group around 0.3?cm?1.