The oxygen dynamics in a reactive Ar/O2high power impulse magnetron sputtering discharge hasbeen studied using a new reactive ionization region model. The aim has been to identify thedominating physical and chemical reactions in the plasma and on the surfaces of the reactoraffecting the oxygen plasma chemistry. We explore the temporal evolution of the density of theground state oxygen molecule O2ðX1RgÞ, the singlet metastable oxygen molecules O2ða1DgÞandO2ðb1RgÞ, the oxygen atom in the ground state O(3P), the metastable oxygen atom O(1D), thepositive ions Oþ2and Oþ, and the negative ion O. We furthermore investigate the reaction ratesfor the gain and loss of these species. The density of atomic oxygen increases significantly as wemove from the metal mode to the transition mode, and finally into the compound (poisoned) mode.The main gain rate responsible for the increase is sputtering of atomic oxygen from the oxidizedtarget. Both in the poisoned mode and in the transition mode, sputtering makes up more than 80%of the total gain rate for atomic oxygen. We also investigate the possibility of depositingstoichiometric TiO2in the transition mode.
QC 20170410