A method includes performing ion beam sputtering with ion assisted deposition to deposit a protective layer on a surface of a body. The protective layer is a plasma resistant rare earth-containing film of a thickness less than 1000 μm. The porosity of the protective layer is below 1%. The plasma resistant rare earth-containing film consists of 40 mol % to less than 100 mol % of Y2O3, over 0 mol % to 60 mol % of ZrO2, and 0 mol % to 9 mol % of Al2O3.