Study on fluorine-doped indium oxide films deposited by RF magnetron sputtering

Fluorine-doped In2O3 films were deposited by rf magnetron sputtering using an In2O3 target at substrate temperatures from RT to 300 degreesC under Ar gas pressure of 1.0 Pa. The fluorine doping was carried out by the following two methods, (1) placing InF3 pellets on the erosion area of the In2O3 target, and (2) introducing CF4 gas into the sputtering chamber. In both cases a systematic increase in carrier density (n) was observed, i.e. in case (1): n increased from 3.1 x 10(19) to 2.9 x 10(20) cm(-3) by placing optimum number of InF3 pellets and in case (2): n increased from 3.1 x 10(19) to 1.1 x 10(20) cm(-3) by introducing CF4 gas at CF4/Ar flow ratio of 4%. The fluorine content of the fluorine-doped films was estimated by electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS), where the inclusion of fluorine was observed to increase by about 30% (F/In at. %) in both cases.