Mass and energy analyses of substrate-incident ions in TiO2 deposition by RF magnetron sputtering

Mass-resolved measurements of substrate-incident ion (SII) current and ion kinetic energy distributions (IEDs) were carried out for TiO2 deposition by rf (13.56 MHz) magnetron sputtering. Substrate-incident ion current was mainly composed of Ar+, O-2(+) and O+. Several minor ions, such as Ti+,TiO+; ArO+ and Ar-2(+) were also detected. The dominant species of substrate-incident ion was O-2(+) at a total pressure higher than 20 mTorr, while Ar+ was dominant one at a total pressure of 2 mTorr with which rutile TiO2 grew on a non-heated substrate. Variations in IEDs for Ar+ and O-2(+) against total gas pressure, oxygen Bow rate and applied rf power were presented. The energy with peak intensity in IED and the mean ion energy increased with both decreasing pressure and increasing rf power. Strong correlation between IEDs and the growth of crystallized TiO2 were observed. Finally we discussed the growth condition of rutile TiO2 films based on the results including the de self-bias voltage.