In this paper, supersonic RF induction plasma deposition of Yttria Stabilized Zirconia (YSZ) has been developed in order to produce dense solid electrolyte membranes for Solid Oxide Fuel Cells (SOFC). Different RF induction plasma torch configurations were tested. The results show that high density layers could be obtained using a supersonic Laval nozzle integrated on a standard torch. 50 to 100 um YSZ coatings with porosity of near 1% could be obtained using this technique at relatively high deposition rates (10g/min.). Attention has been given to the thin coating porosity measurement by using a proper calibration and back scattered electron micrographs of the deposit cross-section coupled with image analysis. Absolute porosity has been measured by using this technique described in another paper of the same conference.