ION ASSISTED DEPOSITION FOR RARE-EARTH OXIDE BASED THIN FILM COATINGS ON PROCESS RINGS

A ring shaped body includes a top flat region, a ring inner side and a ring outer side. The ring inner side comprises an approximately vertical wall. A conformal protective layer comprising 40 mol % to less than 100 mol % of Y2O3 and above 0 mol % to less than 60 mol % of ZrO2 is disposed on at least the top flat region, the ring inner side and the ring outer side of the ring shaped body by ion assisted deposition. The protective layer has a first thickness of less than 300 μm on the top flat region and a second thickness on the vertical wall of the ring inner side, where the second thickness is 45-70% of the first thickness.