Glow discharge mass spectrometry study of the deposition of TiO2 thin films by direct current reactive magnetron sputtering of a Ti target

The properties of titanium oxide thin films deposited by direct current mag netron sputtering of a Ti target are strongly dependent on the sputtering c onditions. The aim of the present work is to investigate the discharge para meters such as plasma potential, discharge voltage, deposition rate, and io n composition of the discharge as a function of the oxygen partial pressure . The plasma potential, relative to the ground, is determined from the ion energy distribution. Working in the constant current discharge mode, we obs erve, with increasing oxygen partial pressure, a drop of the plasma potenti al, an increase of the discharge voltage, a drop of the deposition rate, an d an inversion of the Ti+-TiO+ intensities. For a given discharge current a nd pressure, the drop of the plasma potential and the increase of the disch arge voltage occur at the same gas composition while the drop of the deposi tion rate and the ion intensity inversion happen at an oxygen richer gas co mposition. Both transitions are linearly correlated and depend on the disch arge current. For larger oxygen partial pressure, a third transition appear s corresponding to an inversion between TiO+ and TiO2+ intensities. These r esults lead us to consider three regimes in the reactive sputtering of a Ti target. (C) 1999 American Vacuum Society. [S0734-2101(99)00606-5].