Phasic discharge characteristics in high power pulsed magnetron sputtering

Abstract

As one of the burgeoning physical vapor deposition (PVD) techniques, high power pulsed magnetron sputtering (HPPMS), which boasts high ionization rates of sputtered materials and does not suffer from macro-particles, has been investigated extensively recently. Herein, a new method to break down the discharge current into different characteristic components is employed to study the changes of the various parameters as the target voltage is increased at different pressure. Results show a phasic HPPMS discharge when the target voltage is increased, exhibiting an alternate rise of the peak and the platform of the target current. A small change at the discharge stage is observed with increasing pressure, and some stages are missing in some instances. Five discharge stages are found to correspond to the discharge of Ar atoms, Cr atoms, Ar ions, Cr ions, as well as multiply-charged Ar and Cr ions, respectively, according to the optical emission spectra obtained from the HPPMS discharge plasma. Adjacent discharge stages are also found to overlap under certain discharge conditions.